Transactions of the AIME (American Institute of Mining Engineers)

AIME · 1871 · Industry Journal

The premier US mining engineering technical journal from 1871 onward. Hundreds of volumes covering every major US mining district, technical innovation, and…

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LAWRENCE SCIENTIFIC SCHOOL, Engineering Department.

Tranfarred

*O.Eapn. &e6\ Lib .

Transactions

or THE

xbiERiCAN Institute of Mining

Engineers.

Vol. XXXIII.

CONTAXRINO THB PaPBRS AND D1SCUS8ION8 OP 1902.

NEW YORK CITY: PUBLISHED BY THE IN8TITUTI; ▲T TBI onrcB or thx secretaby.

LAcaiec/iMa

8ee Biographical Notice p. 619.

i - - i X s A T i ( ,' s

KV(i].\i;i:i;s

Vol XXX I II.

'.I IM<t

I'h

Transactions

Op The

American Institute of Mining

Engineers.

Vol. XXXIIL

CoHTAINIJiO THE PaPBRS AND DISCUSSIONS OF 1902.

New York City: Published By The Institute,

At Tiie Ovficb Of Tuk 8Kcretary.

XSl'l

Mar 6 1904

Tranferreta it-fitoa, Gox, Lib,

Preface.

Ik the final preparation of this volume for publication, I bave to acknowledge the valuable aid of Dr. Joseph Struthere, for many years Editor of The Mineral Industry and now As- aiBtant Editor of the TVansactions of the Institute.

R. W. Raymond.

Contents.

Page

OrviccBs, . . . , ix

HONOKARY MSMBKRfi, X

LUT OF MKETI1908, xi

PuBiiCATiONs, xiii

iULES, XVi

Pkoceedinqs.

lew York (Annual) Meeting, February, 1903, xxi

Philadelphia Meeting, May, 1902,

New Haven Meeting, October, 1902 xlvii

Papers.

The Tombstone, Arizona, Mining District. By John A Chubcm, ... 3

Diatom -Earth in Arizona. By W. P. Blake, 38

Tlie Mineral Crest, or the Hydrostatic LeTcI Attained by the Ore-Depositing Solutions, in Certain Mining Districts of the Great Salt Lake Basin. By

Walter P. Jeknky (Discussion, p. 1060), 46

The Reactions of the Ziervogel Process and Their Temperature-Limits. By

BoBEST Henby Bbadfobd, 50

The Auditing of a Mining Company's Accounts. By Chables V. Jenkins, 91 The Effect of Be-Heating upon the Coarse Structure of Over-Heated Steel. By

Fbedebik Gobannskn, 107

Oold Mining in McDnffie County, Georgia. By W. H. Flukeb, . .119

The Direct Cyaniding of Wet-Crushed Ores in New Zealand. By Hamilton

WiNGATE, 125

}(otes on the Treatment of Zinc- Precipitate Obtained in Cyaniding New Zeal- and Ore. By Hamilton Winoate, 136

The Calculation of the Weight of Castings with the Aid of the Planimcter. By

C. M. Schwebin, 142

Determining the Size of Hoisting-Plants. By Edwabd B. Durham, . .145

The Present Situation as to the Specifications for Steel Hails. By William R.

Websteb, 164

Specifications for Steel Forgings and Steel Castings. By William R. Websteb

(Discussion, p. 1042), 170

The Metallurgy of Titanium. By Auouste J. Rossi, 179

The Manganese Industry of the Department of Panama, Republic of Colombia.

[ By K G. Williams, 197

The Mining Industry of the CoBnr d'Alenes, Idaho. By J. R. Finlay, . 235

I Coking in Bee-Hive Ovens with Reference to Yield. By Chables Catlktt, . 272

; Notes on Brazilian Gold-Ores. By Obtille A. Debby, 282

A OoDSideration of Igneous Rocks and their Segregation or Differentiation as

' Belated to the Occurrence of Ores. Ry J. E. Spubb (Discussion, p. 1063), . 288 I Principles Controlling the Geologic Deposition of the Hydrocarbons. By

Gkoboe L. Adams (Discussion, p. 1053), 340

Amarillium. By William M. Coubtis, 347

Vi Contents.

Page

Ore-Deposits of the San edro District, New Mexico. By Mobbison B. Yung

and RiCHABD S. McCaffeby, 350

The Beaumont Oil-Field, with Notes on Other Oil-Fields of the Texas Region.

By BoBEBT T. Hill, 363

The Qold-Field of the State of Minas Geraes, Brazil. By Hebbebt Kilbubn

Scott, 406

The Chemistry of Ore-Deposition. By Walteb P. Jenney (Discussion, p. 1065), 445 The Gamp Bird Mine, Ouray, Colorado, and the Mining and Milling of the Ore.

By Chbsteb Wells Pubington, Thomas H. Woods and (todfbey D.

Doveton, 499

Paddled Iron and the Mechanical Means for its Production. By James P. Bob

(Discassion, p. 1041j, 551

The Original Southern Limit of the Pennsylvania Anthracite-Beds. By Ben- jamin Smith Lyman, 561

The Veins of Boulder and Kalgoorlie. By T. A. Rickabd, 567

The Lodes of Cripple Creek. By T. A. Rickabd, 578

Biographical Notice of Clarence King. By R. W. Raymond, 619 Mining and Metallurgy at the St. Louis World's Fair, 1904. By Joseph A.

Holmes, 650

The Elimination of Arsenic, Antimony and Bismuth from Copper. By Allan

Gibb, 653

The All-Fire " Method for the Assay of Gold and Silver in Blister-Copper. By

Walteb G. Perkins 670

Track-Support for Furnace-Bottoms. By Henby A. Matheb 675

The Copper-Deposits of the Sierra Oscara, New Mexico. By H. W. Tubneb, . 678

The Effect of Tellurium on Brass. By Edwin S. Spebby, 682

Basaltic Zones as Guides to Ore-Deposits in the Cripple Creek District. By

E, A. Stevens, 686

Igneous Rocks and Circulating Waters as Factors in Ore-Deposition. By James

F.Kemp, 699

Ore-Deposits near Igneons Contacts. By Walteb Habvey Weed (Discussion,

p. 1070), 715

Ore-Deposition and Vein-Enrichment hy Ascending Hot Waters. By Walteb

Habvey Weed 747

Silver-Mining and Smelting in Mongolia. By Yang Tsang Woo (Discus- sion, p. 1038) 755

The Development of the Modern By-Product Coke-Oven. By Chbistopheb G.

Atwateb, 760

The Valuation of Mines of Definite Average Income. By H. D. Hoskold, . 777 The Geological Features of the Gold Production of North America. By Wal-

demab Lindgren (Discussion, p. 1077), 790

The Development of the Bessemer Process for Small Charges. By Bbadlky

Stoughton, 846

Geology of Southwestern Texas. By E. T. Dumble, 913

The Blake Stone- and Ore-Breaker: Its Invention, Forms and Modifications,

and its Importance in Engineering Industries. By William P. Blake, . 988

Discussions.

Of Mr. Scotts' Paper on the Evolution of Mine-Surveying Instruments (see

Tratis., xxviii., 679; xxix., 931 ; xxx., 783, 803; xxxi., 25, 716, 884 and 921), . 1035

Of Mr. Woo's Paper on Silver-Mining and Smelting in Mongolia (see p. 755), . 1038

Of Mr. Roe's Paper on Puddled Iron and the Mechanical Means for its Produc- tion (see p. 551), 1041

Of Mr. Webster*s Paper on Proposed Standard Specifications for Steel Forgings

and Castings (see p. 170) 1042

CONTENTS. Vll

Paok

Of Mr. Adama' Paper on Principles ContTolling the Geologic Deposition of the

Hydrocarbons (see p. 340), 1063

Of Mr. Brnmona' Paper on the Secondary Enrichment of Ore-Deposits (see

3Vn., XXX., 177), 1055

Of Mr. Weed's Paper on Section Across the Sierra Madre Occidental of Mexico

(see SVaiM., xxxii., 444), 1069

Of Mr. Jenney's Paper on The Mineral Crest, or the Hydrostatic Level Attained by the Ore- Oepoei ting Solutions, in Certain Mining Districts of the Great Salt LAke Basin (see p. 46), 1060

Of Mr. Sporr's Paper on A Consideration of Igneous Rocks and their Segrega- tion or Differentiation as Related to the Occnrrence of Ores (see p. 288), . 1063

Of Mr. Jenney's Paper on The Chemistry of Ore-Deposition (see p. 445), . . 1065

Of Mr. Weed's Paper on Ore-Deposits Near Igneons Contacts (see p. 715), . T 1070

Of Mr. Landfcren's Paper on the Geological Features of the Gold Prodnction of

North America (see p. 790) 1077

Officers.*

For year endio February, 1903.

Preeibent.

EBEN R OIX)OTT, New York City.

CARIjOS F. x>e LANDERO , Pachuca, Mexico.

JOHN E. HARDMAN Montreal, Canada.

JOHN HAYS HAMMOND New York City.

(Tenn expires February, 1908.)

S. F. EMMONS Waahingion, D. C.

JAMES GAYLEY New York City.

J. HENRY LEE Baltimore, Md.

(Term expires February, 1904.)

Managers.

B. H. BACON Soudan, Minn.

E. V. lyiNVILLIERS Philadelphia, Pa.

WILLIAM KENT. Passaic, N. J,

(Term expires February. 1903.)

OEORGE A. CROCKER New York Citv.

HORACE V. WINCHELL Butte, Mont.

CXEMENS C. JONES Richmond, Va.

(Term expires Februar>-, 1904.)

E. W. PARKER Washington, D. C.

JAMES W. NEILL Salt Lake City, Utah.

M. D. VALENTINE Woodbridge, N. J.

(Term expires Februarj', 1905.)

Becretarg. areasurer.

R W. Raymond, Theodore D. Rand,

99 John St., New York City. Philadelphia, Pa.

The following officers were elected at the Annual Meeting, February, 1903. PrmdetU, Albert R. Ledoux, N. Y. City; Vice-Presidents (to serve two years), John Markle, Jeddo, Pa. ; Philip W. Moen, Worcester, Mass. ; James F. Kemp, N- Y. City. Managers (to serve three years), Heinrich Ries, Ithaca, N. Y.; B. R Lawrence, N. Y. City; F. Klepetko, Butte, Mont.; jPreasurerj Theodore D. Band, PhUadelphia, Pa.; Secretary, R. W. Raymond, N. Y. City. (Note.— Mr. Band resigned hia position as Treasurer shortly before his death in April, 1903, and Mr. Frank Lyman, N. Y. City, was appointed his successor. )

Iionorart Members.

Honorary Members.

Pbof. Richard Akkrman Stockholm, Sweden.

Sir Lowthian Bell Middlesborough, England.

Dr. Thomas M. Drown South Bethlehem, Pa.

Prop. Haton de la Goupilliere Paris, France.

Prof. Hans Hcefer Leohen, Austria.

Prof. Dr. Bruno Kerl Berlin, Germany.

Prof. J. P. Lesley* Philadelphia, Pa.

M. Floris Osmond Paris, France.

Sir William C. Roberts- AustenI London, England.

Prof. Dr. Hermann Wedding Berlin, Germany.

Prof. Dimitry Constantin Tschkrnopf St Petersburg, Russia.

Died June 1, 1903. t Dietl November 28, 1902.

List Of Meetings. Xi

U8T OF THE MEETINGS OF THE INSTITUTE AND THEIR LOCAL- ITIES FROM ITS ORGANIZATION TO OCTOBER, 1902.

Transactions. Kunber. Place. Date. Vol. Page

L WUkea-Barre, Pa.* May, 1871 i. 3

n. Bethlehem, Pa. August, 1871 i. 10

in. Troy, N. Y November, 1871 i. 13

IV. Philadelphia, Pa. February, 1872 L 17

V. New York, N. Y.* May, 1872 i. 20

VI. Pittsbnrg, Pa. October, 1872 i. 26

VII. Boston, Mass February, 1873 i. 28

VIIL PhUadelphia, Pa.* May, 1873 ii. 3

IX. Easton, Pa, October, 1873 ii. 7

X. New York, N. Y February, 1874 ii. 11

XL St, Louis, Mo.* May, 1874 iiL 3

XIL Hazleton, Pa October, 1874 iii. 8

XIII. New Haven, Conn February, 1875 iii. 16

XIV. Dover, N. J.* May, 1876 iv. 3

XV. Cleveland, O October, 1875 iv. 9

XVL Washington, D. C February, 1876 iv. 18

XVIL Philadelphia, Pa.t June, 1876, v. 3

XVIIL Philadelphia, Pa October, 1876 v. 19

XIX. New York, N. Y February, 1877 v. 27

XX. Wilkes-Barre, Pa.* May, 1877 vi. 3

XXL Amenia,N. Y October, 1877 vi. 10

XXIL Philadelphia, Pa. February, 1878 vi. 18

XXin. Chattanooga, Tenn.* May, 1878 vii. 3

XXIV. Lake George, N. Y October, 1878 vii. 103

XXV. BalUmore, Md.* February, 1879 vii. 217

XXVL Pittsburg, Pa May, 1879 viii. 3

XXVII. Montreal, Canada September, 1879 viii. 121

XXVIIL New York, N. Y.* Februaiy, 1880 viii. 276

XXIX. Lake Superior, Mich., August, 1880 iz. 1

XXX. Philadelphia, Pa.,*. February, 1881 ix. 276

XXXL Staunton, Va, May, 1881 x. 1

XXXII. Harrisburg, Pa October, 1881 x. 119

XXXIIL Washington, D.C.* February, 1882 x. 226

XXXIV. Denver, Col August, 1882 xi. 1

XXXV. Boston, Mass.* February, 1883 xi. 217

XXXVI. Roanoke, Va, June, 1883 xii. 3

XXXVII. Troy,N.Y October, 1883 xii. 176

XXXVIIL Cincinnati, O.* February, 1884 xii. 447

XXXIX. Chicago, HI May, 1884 xiii. 1

XL. Philadelphia, Pa September, 1884 xiii. 286

XLL New York, N. Y.* February, 1885 xiii. 686

Anniial meeting for the election of officers. The rules were amended at the Chattanooga HMethiK. 31*7. 1878, changing the annual election from May to February, t Began In May at Easton, Pa., for the election of officers, and adjourned to Philadelphia.

Xll LIST OF MBBTINOS.

Trantaotions.

Number. Place. Date. VoL Fage

LII. Chattanooga, Tenn May, 1885 ziy. 1

XLIII. Halifax, N. 8 /. September, 1885 xiv. 807

XLIV. Pittsburg, Pa.* February, 1886 xiv. 687

XLV. Bethlehem, Pa May, 1886 xy. Ixiii.

XLVI. St. Louis, Mo October, 1886 xv. Ixx.

XLVII. Scranton, Pa.* February, 1887 xv. Ixxvii.

XLVIII. Utah and Montana July, 1887 xvi. xvii.

XLIX. Duluth, Minn July, 1887 xvi. xxiv.

L. Boston, Mass.*. February, 1888 xvi. xxviii.

LI. Birmingham, Ala. May, 1888 xvii. xix.

LIL Buffalo, N. Y October, 1888 xvii. xxiv.

Lin. New York, N. Y.* February, 1889 xvii. xxxi.

LIV. Colorado June, 1889 xviii* xvii.

LV. Ottawa, Canada October, 1889 xviiL xxiv.

LVI. Washington, D.C.* February, 1890 xviii. xxx.

LVIL New York, N. Y September, 1890. xix. vii.

LVIIL New York, N. Y.* February, 1891 xix. xxv.

LIX. Cleveland, O June, 1891 xx. xvi.

LX. Glen Summit, Pa October, 1891.. xx. Ixi.

LXL Baltimore, Md.* Febniary, 1892 xxi. xix.

LXII. Platteburgh, N. Y June, 1892 xxi. xxxiii.

LXIIL Reading, Pa. October, 1892 xxi. xliv.

LXIV. Montreal, Canada* February, 1893 xxi. Hi.

LXV. Chicago, 111 August, 1893 xxii. xiii.

LXVI. Virginia Beach, Va.* February, 1894 xxiv. xvii.

LXVn. Bridgeport, Conn October, 1894 xxiv. .

LXVIIL Florida! March, 1895 xxv. xix.

LXIX. Atlanta, Ga October, 1895 xxv. xxxiii.

LXX. Pittsburg, Pa.* February, 1896 xxvi. xvii.

LXXI. Colorado September, 1896 xxvi. xxix.

LXXn. Chicago, 111 February, 1897 xxvii. xvii.

LXXm. Lake Superior July, 1897 xxvii. xxx.

LXXIV. Atlantic City, N. J.* February, 1898 xxviii. xvii.

LXXV. Buffalo, N. Y October, 1898 xxviii. xxxvi.

LXXVI. New York City* February, 1899 xxix. xvii.

LXXVn. California September, 1899 xxix. xlix.

LXXVIIL Washington, D. February, 1900 xxx. xix.

LXXIX. Canada August, 1900 xxx. xlv.

LXXX. Richmond, Va.* February, 1901 xxxi. xix.

LXXXI. Mexico November, 1901. .xxxi. and xxxii. cxviii.

LXXXIL Philadelphia, Pa.t May, 1902 xxxiii.

LXXXIU. New Haven, Conn October, 1902 xxxiii.

Annual meeting for the election of officers.

t Begun in Febniary at New York City, for the election of officem, and adjourned to Florida.

X " " " " " 'to Philadelphia.

Publications.

The publications of the Institute comprise :

Pamphlets.

1. The minutes of the Proceedings of each Meeting.

2. Such of the papers presented or read by title at each Meeting as are furnished by the authors and approved by the Council for full publication. (In nearly all cases in which papers, the titles of which appear in the Proceedings, are not subsequently published,. they have been withdrawn by the authors.) These papers are pub- lished separately in pamphlet form, and are marked subject to- revision." Beyond the edition distributed, without charge, to mem- bers and associates not in arrears, a small supply is retained to meet subsequent demand. There are no copies on hand of papers read before 1880. The stock is nearly complete from 1880. These papers are for sale at the office of the Secretary, or are sent to pur- chasers by mail or express, charges paid, on receipt of the price, as follows :

No. OP Pages. I Single Copies. 10 Copies.

8orle ! 10 10 10 60

9 to 12 indufiive 0 10 0 80

IS to 16 i 0 12 I 100

17 to 20 0 16 I 1 25

21 to 21 0 20 I 1 50

to 40 " 0 25 I 2 00

41 to 56 " 0 80 I 2 50

57 to 72 " 0 85 I 8 00

73 to " 0 40 I 8 25

to 104 0 45 ! 8 50

106 to 120 " I 0 50 I 8 75

20 Copies.

Pftpers with folders and inserted plates subject to special price.

Transactions. The volumes of Transactions which are published annually, con- tain the list of oflScers, rules, etc., the Proceedings, and the papers- revised for final publication. (In this revision, after the prelimi- nary publication, authors are permitted to use the largest liberty ; and the changes and additions made in papers are sometimes im- portant. It should be borne in mind by those who study or quote a paper in the preliminary edition, that they may not have in that form the ultimate and deliberate expression of the author's views. It should be added, however, that in the majority of cases there are no important changes.) These volumes are for sale as follows, in* paper covers :

Xiv Publications.

Vols. I. to IV., inclusive, each, $3 OO

Vols. V. to VIII., inclusive, each, 4 OO

Vols. IX. and X. (a small supply only on hand), . . 10 OO

Vols. XI. to XXIX., inclusive, each, 5 OO

Vols. XXX. and XXXI., each, 6 OO

Vol. XXXII., 5 OO

Half-morocco binding, $1 extra per volume.

Indexes and Special Editions. Index, Vols. XVI. to XX., inclusive, paper, . . . . $1 00 Index, Vols. XXI. to XXV., inclusive, cloth, . . 1 25

Index, Vols. XXVI. to XXX., inclusive, cloth, . . . 1 60 Indexes, Vols. I. to XV.,XVL to XX., XXL to XXV.,

XXVI. to XXX., bound in one volume, cloth, . 4 00 "The Genesis of Ore-Deposits," comprising the famous treat- ise of the late Professer Franz Posepny, with the suc- cessive discussions thereof by Le Conte, Blake,Winchell, Church, Emmons, Becker,Cazin, Rickard and Raymond (all of which were published in Volumes XXIII. and XXIV. of the Transactions of the Institute, and subse- quently in the special Posepny Volume," issued by the Institute) ; also, later papers by Van Hise, Emmons, Weed, Lindgren,Vogt, Kemp, Blake, Rickard and others, and the discussions of these papers by De Launay, Beck, and many others (some of these were included in Vol- ume XXX. and the balance will appear in Volume XXXI.) ; also a complete bibliography of the Institute papers and discussions on this subject from 1871 to the present time.

The original Posepny volume comprised 265 pages, and was sold for $2.50, at which price the edition was long since exhausted. The present volume is an octavo of 825 pages, bound in " book-linen," of the same color as the standard binding of the Transactions, . . . $6 00

Half-morocco bound copies, 7 00

Evolution of Mine-Surveying Instruments." This is a volume of about 400 pages, issued in the same style as the foregoing, and containing the original paper of Mr. Dunbar D. Scott on that subject {Transactions, XXVIII.), first published in 1898, together with later papers, continuing the same subject, and discussions thereof, by Hoskold, Lyman, Davis and many others. Memorial of Alexander L. HoUey, with portrait, cloth, . 1 00 Olossary of Mining and Metallurgical Terms (1881), cloth, . 60

List of Members, Rules, etc., paper, 50

Publications.

Authors' Editions of Pamphlets.

Extra copies, when ordered before the printing of the pamphlet edition, are furnished to authors, under Rule VII., at the following rates:

No. OF Paobs.

I 4orleBft

' 5 8 inclusive

9 to 12 -

17 to 20 "

25 to 28 "

29toS2 "

Oovexs (including print- ing on first page of the

I Copies.

fl25

100 Copies.

$150

250 Copies.

I Each addi- jtlonallOOoopiee I above 250.

Papers with folders and inserted plates subject to special price.

All communications and remittances should be addressed to R. W. Raymond, Secretary, 99 John St., or P. O. Box 223, New York City.

Rules

ADOPTED MAY, 187S. AMENDED MAY, 1J376, 1877, AND 1878, FEBRUARY, 1880, 1881,. 1887, 1890, 1896 AND 1903.

Objects.

The objects of the American Institute of Mining Enoineers are to promote the arts and aciences connected with the economical production of the useful min- erals and metals, and the welfare of those employed in these industries, by meana of meetings for social intercourse, and the reading and discussion of professional papers, and to circulate, by means of publications among its members and asso- ciates, the information thus obtained.

Membership.

The Institute shall consist of Members, Honorary Members, and Associates. Members and Honorary Members shall be professional mining engineers, geolo- gists, metallurgists, or chemists, or persons practically engaged in mining, metal- lurgy, or metallurgical engineering. Associates shall include all suitable persons desirous of being connected with the Institute, and duly elected as hereinafter provided. Each person desirous of becoming a member or associate shall be pro- posed by at least three members or associates, approved by the Council, and elected by ballot at a regular meeting (or by ballot at any time conducted through the mail, as the Council may prescribe) upon receiving three-fourths of the votes cast, and shall become a member or associate on the payment of his first d ues. Each person proposed as an honorary member shall be recommended by at least ten members or associates, approved by the Council, and elected by ballot at a regular meeting (or by ballot at any time conducted through the mail, as the Council may prescribe) on receiving nine-tenths of the votes cast ; Provided, that the number of honorary members shall not exceed twenty. The Council may at any time change the classification of a person elected as associate, so as to make him a member, or vice versa, subject to the approval of the Institute. All members and associates shall be equally entitled to the privileges of membership ; Provided, that honorary members shall not be entitled to vote, and members or associates whose post-office address shall be outside of the United States, Canada and Mexico shall not be entitled to vote by mail, except upon proposed amendments to the Rules.

Rules. Xvu

Anj member or associate may be stricken from the list on recommendation of the Comicil, by the vote of three-fourths of the members and associates present at any annual meeting, due notice haying been mailed in writing by the Secretary to the said member or associate.

Dues.

The dues of members and associates shall be ten dollars, payable upon their election, and ten dollars per annum thereafter, payable in advance on the first day of each calendar year. Honorary members shall not be liable to dues. Any member or associate not in arrears may become, by the payment of one hundred and fifty dollars at one time, a life-member or associate, and shall not be liable thereafter to annual dues. Any member or associate in arrears may, at the discre- tion of the Council, be deprived of the receipt of publications, or stricken from the list of members when in arrears for one year ; Providedy that he may be re- stored to membership by the Council on payment of all arrears, or by re-election after an interval of three years.

Officers.

The affairs of the Institute shall be managed by a Council, consisting of a Presi- dent, six Vice-Presidents, nine Managers, a Secretary and a Treasurer, who shall be elected from among the members and associates of the Institute at the annual meetings, to hold office as follows :

The President, the Secretary, and the Treasurer for one year (and no person shall be eligible for immediate re-election as President who shall have held that office subsequent to the adoption of these rules, for two consecutive years), the Vice-Presidents for two years, and the Managers for three years ; and no Vice- President or Manager shall be eligible for immediate re-election to the same office at the expiration of the term for which he was elected. At each annual meeting a President, three Vice-Presidents, three Managers, a Secretary, and a Treasurer shall be elected, and the term of office shall continue until the adjournment of the meeting at which their successors are elected.

The duties of all officers shall be such as usually pertain to their offices, or may be delegated to them by the Council or the Institute ; and the Council may in its discretion require bonds to be given by the Treasurer. At each annual meeting the Council shall make a report of proceedings to the Institute, together with a financial statement

Vacancies in the Council may occur by death or resignation ; or the Council may, by a vote of the majority of all its members, declare the place of any officer vacant, on his failure for one year, from inability or otherwise, to attend the Council meetings or perform the duties of his office. All vacancies shall be filled by the appointment of the Council, and any person so appointed shall hold office for the remainder of the term for which his predecessor was elected or appointed ; Prtmded, that the said appointment shall not render him ineligible at the next annual meeting.

Five members of the Council shall constitute a quorum ; but the Council may appoint an Executive Committee, or business may he transacted at a regularly called meeting of the Council, at which less than a quorum is present, subject to

B

XVlll RULBS.

the appiOTal of a majority of the Council, subflequently gien in writing to the Secretary, and recorded by him with the minutes.

Elections.

The annual election shall be conducted as follows : Nominations may be sent in writing to the Secretary, accompanied with the names of the proposers, at any time not less than thirty days before the annual meeting ; and the Secretary shall, not less than two weeks before the said meeting, mail to eyery member or asso- ciate (except honorary members) a list of all the nominations for each office so received, together with a copy of this rule, and the names of the persons ineligible for election to each office ; and if the Council, or a Committee thereof, appointed for the purpose, shall have recommended any nominations, such recommendation may also be sent to members and associates with the said list of all nominations made, but not upon the same paper. And each member or associate, qualified to Tote, may vote, either by striking from or adding to the names of the said list, leav- ing names not exceeding in number the officers to be elected, or by preparing a new list, signing said altered or prepared ballot with his name, and either mail- ing it to the Secretary or presenting it in person at the annual meeting ; Provided that no member or associate in arrears since the last annual meeting shall be allowed to vote until the said arrears shall have been paid. The ballots shall be received and examined by three Scrutineers, appointed at the annual meeting by the presiding officer ; and the persons who shall have received the greatest num- ber of votes for the several offices shall be declared elected, and the Scrutineers shall so report to the presiding officer. The ballots shall be destroyed, and a list of the elected officers, certified by the Scrutineers, shall be preserved by the Secretary.

Meetings.

The annual meeting of the Institute shall take place on the third Tuesday of February, at which a report of the proceedings of the Institute and an abstract of the accounts shall be furnished by the Council. Other meetings shall be held in each year, at such times and places as the Council shall select, and notice of all meetings shall be given by mail, or otherwise, to all members and associates, at least twenty days in advance.

Every question which shall come before any meeting of the Institute, shall be decided, unless otherwise provided by these Rules, by the votes of a majority of the members then present Any member or associate may introduce a stranger to any meeting ; but the latter shall not take part in the proceedings without the consent of the meeting.

vn.

Papers And Publications.

The Council shall have power to decide on the propriety of communicating to the Institute any papers which may be received, and they shall be at liberty, when they think it desirable, to direct that any paper read before the Institute shall

Rules. Xix

be printed in the Tranaaetiona, Intimation, when practical, shall be given, at eich general meeting, of the subject of the paper or papers to be read, and of the questions for discussion at the next meeting. The reading of papers shall not be delajed beyond such hour as the presiding officer shall think proper ; and the election of members or other business maybe 'adjourned by the presiding officer, to permit the reading and discussion of papers. The published papers and vol- Mines of TranaacHons shall be distributed to all members and associates not in ineaia, and may be sold to the public upon such conditions as the Council shall prescribe ; but the Ck>uncil may, in its discretion, omit sending to members and laociates outside of the United States, Canada and Mexico, special circulars, uileaBthe same contain proposed amendments to the Rules.

The copyright of all papers conmiunicated to, and accepted by, the Institute, ghall be vested in it, unless otherwise agreed between the Council and the author. The author of each paper read before the Institute shall be entitled to twelve copies, if printed, for his own use, and shall have the right to order any number Of copies at the cost of paper and printing, provided said copies are not intended for sale. The Institute is not, as a body, responsible for the statements of fact or opinion advanced in papers or discussions at its meetings, and it is understood that papers and discussions should not include matters relating* to politics or purely to trade ; nor shall the Council or the Institute officially approve or dis- approve any technical or scientific opinion or any proposed enterprise outside the management of the meetings, discussions and publications of the Institute, as pro- vided in these Bules ; Provided however, that committees may be appointed by the Goandl or the Institute to make investigations and submit reports at meetings ci the Institute ; but no action shall be taken binding the Institute for or against the oondosions of any such reports.

Amendments.

These Rules may be amended at any annual meeting by a two-thirds vote of the memberB present ; Provided that written notice of the proposed amendment shall have been given at a previous meeting ; and Provided alsOf that the amendment or amendmentB so adopted shall be printed upon a ballot and sent, not later than the next distribution of printed matter, to all members and associates not in arrears for the preceding year (except honorary members and foreign members elected before February, 1880), and each person receiving the same shall be requested to return it to the Secretary with his written vote of Yes or No to each amendment, and his signature ; and the President shall appoint as Scrutineers three members associates, who shall examine all of the said ballots which shall have been re- turned within one month from the date of their distribution, and shall report the re:ialt ; and the Secretary shall publish and distribute to members, not later than the next distribution of printed matter, an announcement of the said result so re- ported, together with the text of the additional or amended rule or rules so adopted ; and the amendment or amendments approved by the majority of the ballots so zetunied and reported shall become part of these Bules from and after the publication of said announcement by the Secretary.

-- iel:ity-Second (Thirty- Second Annual)

New Vox-i City, February, 1902.

-ncetiS' the above time and place are con-

cero -p,o\e VI., on February 18, 1902, at the office of

ggribed 99 John Street, New York City, for the coun1>

Q0Xic\ for tbiB arrangement were stated in the Secre-

_-cot Meeting of the Institute was one of great international, as

ibe generosity of other citizens throughout the Republic, as well as

labor on the part of the officers of the Institute, and still entails an

ljxo amonnt of publication and correspondence upon this office. It is

ly impracticable to organize another meeting for February next

Council has, therefore, directed that the meeting of the Institute shaU

£ stngli purely formal session, to be held, as prescribed by Rule VL,

18, 1902, at noon, in the office of the Secretary, 99 John Street, New

r-tT pnrpoae of the counting of ballots and the presentation of the

I Bepo Council, which will be subsequently printed and distributed,

1 The titles of all papers accepted will also be presented, and these papers

jyjj distributed for discussion at a later meeting, or adjourned

. bearing the same number, as may be hereafter decided, which will take

~fi the %, at a time and place to be hereafter announced."

The session began at the time and place above-named. lAeBBTS' Anton Metz, B. Dunham and P. F. O'Rourke were appointed Scrutineers.

The Annual Report of the Council was presented, as follows : Annual Report of the Council. accordance with the Rules, the Council makes the foUow-

financial statement of the Secretary and the Treasurer

ceipts from all sources for the year endinsc December

onl /'including the balance of J1478.12 on hand December

— " Moevaent waa substantially repeated in Circular No. 1 of 1902.

XXll PROGBBDINGS OF NEW YORK MEBTINO.

31, 1900), of $89,059.55, and expenditures of $84,321.26, leav- ing $4748.30 cash on hand. No account is taken in this state- ment of the increased value of the assets of the Institute in back- volumes of the Transactions office-furniture, etc. In addition to the cash on hand, the Institute possesses invested ftinds of the par value of $19900 and market value of more than |20,000, yielding about $950 interest annually ; and on December 31st there were no bills payable, or outstanding obligations. The detailed statement is as follows :

Receipts.

Balance from statement of December 31, 1900, $1,478 12

Annual dues, $26,648 32

Life membership, 3,761 17

Binding of TnvMOJcdoM 2,492 63

Sale of publications, 3,664 60

Electrotypes, 48 02

Interest on bonds and deposits, 975 39

Miscellaneous, 1 40

37,591 43

$39,069 55 DiSBURSBMBNTS.

Printing volume xzz. of TrauMdicfiM of 1900, . $3,561 72

pamphlet edition of papers, 3,824 53

" new volume on Ore-Deposits, . 1,105 80

'' circulars and ballots, 280 27

Binding volume xxz. and miscellaneous volumes

of TrauBouituyn 2,642 83

exchanges, 208 20

Engraving and electroty ping, ' . . . . 1,002 14 Secretary's department, including clerks, stenog- raphers, and expenses of editing and

proof-reading, 8,980 00

Postage, including post-office box rent, . . 2,332 37

Stationery, 757 70

Rent, 2,500 00

Express and freight charges, 1,420 83

Telephone, 137 22

Telegrams, cablegrams and car fare, ... 68 34

Office equipment, 131 06

Assistant Treasurer's department, . 3,672 03

Storage of TranKuAions 112 84

Special stenographers and expenses of meetings, . 583 70

Office supplies and repairs, 464 82

Insurance, 26 98

Collection charges, 7 52

Extra clerical help, 106 32

Library addition and catalogist, 393 03

34,320 25

$4,749 30

PROCBBDINGS OF NEW YORK MBBTING. XXlll

Volume XXX. of the Transactional an octavo of 1157 pages, iBraed and distributed daring the year, is one of the largest ever printed by the Institute, and is unquestionably equal to any of its predecessors in the value of its contents.

It is but fair to mention, as contributing to the labors and expenses of Ae year, the preparation of two special additional volumes of considerable size, both of which will be issued in 1902, viz. :

1. The special volume on the genesis of ore-deposits, a republi- cation of the former " Posepny " volume (containing the mem- orable treatise contributed to the Transactions in 1893 by the late Franz Posepny, and the discussion thereof by numerous con- tributors), together with important papers and discussions of later date by many eminent European and American authori- ties, and constituting a summary of the present state of the science of ore-deposits. Although the several contributions included in this volume are accessible to members in the vol- umes of our Transactions for the last 8 years, it is believed that this coUection of them in one book, duly indexed, will be wel- comed by instructors, students, and active mining engineers.

2. The special volume on mine-surveying instruments, con- taining the original paper of Mr. Dun\)ar D. Scott on this sub- ject, with much valuable criticism and additional information, contributed by experts in other countries as well as in the United States.

Moreover, it should be added that a consolidated index to Volumes XXVI.— XXX., inclusive, was prepared during the year, and will be issued to members early in 1902. It is, per- haps, unnecessary to say that the preparation of such analytical indexes, at intervals of five years, has been believed, and has proved itself, to be a most important means of making our Tranaactions a convenient cyclopsedia of practice and progress for all students of modern mining and metallurgy.

Two meetings have been held during the year : the LXXXth (XXXIst Annual) meeting, in February, and the LXXXIst, in the City and Republic of Mexico, in November. The published Proceedings of these meetings, with the appended description of the entertainments and excursions connected therewith, ob- viate the necessity of any further comment in this report. Vols. XXXl. and XXXH. of the Transactions will sufficiently prove

Proceedings Of New York Meeting.

the amount, variety and value of the technical contributions elicited ; and it is sufficient to say, here that the year 1901 has rather raised than lowered the standard of pleasure and profit set up in previous years for the meetings of the Institute.

The exceptional labor and responsibility devolved upon the Secretary of the Institute in connection with the meetings and the publications of the year was doubled by the death of his son, who had been for many months his chief editorial assist- ant. At a meeting of the Council, held Dec. 17, the following minute was adopted :

' ' The Council desires to place on record its deep sense of the loss sustained, not only by the Secretary himself, but also by the American Institute of Mining Engineers, through the death, October 28, 1901, of Mr. Alfred Baymond, the only son and for many months past the efficient editorial assistant, of Dr. B. W. Baymond, Secretary of the Institute.

At successive meetings of the Institute, and in correspondence or personal in- tercourse with its members, Mr. Baymond had won a wide and hearty recognition of his brilliant talents and charming personal character. His removal by death in the prime of his useful and most promising career deprives hb parents of the dearest of sons, his innumerable friends of a cherished companion, the Institute of an esteemed and beloved servant, and the world of a devoted, generous and active lover of mankind."

Changes in membership have taken place during the year as follows : 301 members and 25 associates have been elected ; 6 associates have become members ; the deaths of 24 members and 7 associates have been reported ; 40 members and 1 asso- ciate have resigned, and 24 members and 3 associates have been dropped from the roll by reason of non-payment of dues, loss of correct address, etc.*

At date of Inst report

Gains: By Election

" Change of Status- Losses : By Besignation

Change of Status..

" " Death

H. M.

F. M.

gain

Total Josses

Present membership 10

M.

A.

Totala.

Many of these, no doubt, will be reinstated, as has been the case in former years.

Procbbdinos Of New Tork Meeting. Xxv

The list of deaths reported during the year comprises the Mowing names Honorary Member. Joseph Le Conte (1895). Members and Associates. — Carl Angstrom (1885), C. S. Batter- man (1901), R. C. Chambers (1886), S. S. Chisholm (1897), Frank E. Corbett (1899), Albert Conro (1888), E. C. Darley (1888), W. H. Emanuel (1881), Mario Escobaji (1898), Albert tt Haider (1891), Mellen S. Harlow (1895), W. E. Johnson (1898), Clarence King (1899), Porter King (1897), W. J. Koehler (1891), G. A. Kornberg (1895), James F. Lewis (1875), E. K Lindsay (1900), Duncan M. Maclaren (1898), Charles A. Macy 2d (1894), Thomas S. McNair (1877), James E. Mills (1877), James Moore (1875), S. Fisher Morris (1874), Frank Owen (1894), R. P. Rothwell (1871), William Van Slooten (1884), Joseph R. Walker (1885), Edward Walsh, Jr. (1874), William Watson (1897), Frank Williams (1888).

Biographical Notices of Joseph Le Conte, Clarence King, James F. Lewis and R. P. Rothwell have been prepared sepa- rately, and will be published in the Transactions. Concerning the remainder of the above list, such data as the Secretary has been able to obtain are given below, in the alphabetical order of the names. Any appropriate biographical data concerning these names, or others of the above list, which may be received hereafter, will be included in the next annual report.

Christopher S. Batterman was born in 1859 at Placerville, Cal., and educated at the University of California, from which he was graduated in 1879 as mining engineer — a profession towards which he naturally inclined, his father having been a mine-superintendent on the Comstock lode, Nevada, in the days of its greatest glory. He was subsequently employed as a mine-surveyor or manager in Mexico, Arizona, Nevada, Colorado and Montana. As the designer of an improved mining-transit, he is mentioned in our l}ransactions.-\ Mr. Bat- terman frequently appeared in mining lawsuits as an expert witness. He became a member of the Institute only a few months before his death, which occurred Oct. 7, 1901, at Butte, Montana. At the time of his death he was Chief Engineer of the Amalgamated Copper Company and Superintendent of the

The figures in parenthesis indicate the year in which t]ie persons named were elected by the Institute. t Trans,, xxviii., 728.

Xxvi Proceedings Of New Tore Meeting.

mines of the Boston and Montana Cons. Copper and Silver Mining Co. of Butte.

a. C. Chambers became a member of the Institute in 1886. He died in April, 1901, at Salt Lake City, where he had been for many years prominent as a mine-manager, mine-owner, and expert adviser of wealthy capitalists engaged in mining ven- tures. The celebrated Ontario mine, in Utah, is but one of the properties selected by his judgment, and developed by him or under his advice, which have proved for long periods profit- ably productive. Indeed, for many years the " Chambers Syndicate," represented by him, was regarded throughout the Rocky Mountain region as a combination of capital sagaciously directed in its investments, bold in its enterprises, and not easily discouraged, or thwarted by lack of means, in their exe- cution.

Frank E. Corbetiy born in 1864, died at Butte, Montana, March 14, 1901. He was a native of Virginia, and a graduate of the law department of the famous University of that State, planned and established by Thomas Jefferson. In 1889, at the early age of 25, he took up his residence in Butte City, where he engaged in the practice of law. His refined nature, winning personality, intellectual power, professional skill and wide cul- ture, both securing and holding for him an important clientage, soon made him eminent and successful. On one side or the other, he appeared as counsel in nearly all the important min- ing lawsuits tried in Butte after his arrival there ; and it may be added that this statement covers a period during which that place was the scene of contests probably exceeding, in the aggre- gate value of the interests at stake, the contemporaneous sim- ilar litigation in all other parts of the United States.

Like other leaders of the Western bar called to deal with the intricate problems raised by the obscure, inadequate and inconsistent features of the U. S. mining law, Mr. Corbett ap- preciated fully the value of the contributions made in the Transactions of this Institute to the science of ore-deposits; and in 1899 be became an Associate of the Institute, in order to avail himself of the new light thus afforded to the legal as well as to the technical student of such subjects.

Not only at the bar, but also in politics, he achieved an early distinction, without sacrifice of honor or reputation. He was

PROCBBDINGS OF NEW YORK MEETING. XXVll

Speaker of the Seventh Legislative Assembly of Montana, which adjourned but six days before his death ; and when he pwsed away, in the full vigor of his prime, after a short attack of {neum(Hiia (that awfully frequent and swiftly fatal scourge of h%h altitudes), friends and foes alike joined to praise and to mourn him.

Edward C. Darley was born in 1846 in New York City ; be- came a mechanical and constructing engineer, and was for many years connected with James T. Witherow and Co., of Pittsburg, Pa. In this capacity he superintended the con- struction of the blast-furnaces of the Watts Iron and Steel Co., Middlesboro', Ky. ; the Oswego Iron and Steel Co., Oswego, Oregon; the Ashland Iron Co., Ashland, Wisconsin; and the Vulcan Iron Works, St. Louis, Mo. He died at Chicago in April, 1901.

William H. Emanuel was born in 1860 in Catasauqua, Pa., where he died May 8, 1901. After a preliminary public-school education he entered Lafayette College, Easton, Pa., where he was graduated in 1881. Subsequently he was for two or three years chemist of the Hepauno Chemical Company, manufac- turers of high explosives, at Repauno, N. J., not far from CSiester, Pa., and the Du Pont Powder Company of Wilming- ton, Del., both of which were under the direction of Mr. E. J. Do Pont (afterwards killed by an explosion at the latter works). In 1885, by reason of his health, he went to Colorado, where, in 1886, he succeeded his father as the agent for that region ot the Laflin A Rand Powder Company, to which business was soon added the agency for the Rand Drill Company. His en- ergy and success in these positions led to his appointment (with the consent, and, indeed, at the suggestion, of Mr. A. C. Rand), as agent for Frazer & Chalmers, the well-known makers of mining, milling and metallurgical machinery. It is strong proof of his ability and loyalty, and of the confidence reposed in him, that he acted for years as agent, at one and the same time, for all three of the concerns mentioned, neither of which had reason to feel that it would be better served by a repre- seDtative giving his whole time to its interests alone. His labors in this triple capacity involved much travel and a wide acquaintanceship ; so that he was personally known and highly esteemed in New York and London, as well as in Denver and

XXVlll PROCEEDINGS OF NEW YORK MEETING.

San Francisco, and throughout the Pacific coast States and Territories.

Albert Herbert Holder who died in London, June, 1901, was a fellow of the Royal Institution of British Architects and a member of the Federated Institute of Mining Engineers, the Austrian Institution of Civil Engineers and Architects, and the American Institute of Mining Engineers. He joined the Institute in 1891, and after that date was engaged as a mining engineer in Rhodesia and the Transvaal, in South Africa, and in British Columbia. He returned to South Africa at the end of 1900, but apparently was not then able to resume work in the mining district; at least, his final .residence, whether re- sumed by reason of illness or for some other cause, was London.

William Ellery Johnson was born in 1856 at Hopkinton, Mass. His parents moved in 1857 to Iowa Falls, Iowa, where he received a public-school education, which he supplemented with a college course at the State University, Iowa City. In 1878 Mr. Johnson went to Southern Colorado, where he wa engaged in railway-surveys in the neighborhood of Alamosa. In 1879 he settled at Canon City, where he started the Canon City Water Co., and pushed its works to completion. In 1880 he took charge of the operations of the Colorado Fuel and Iron Co. in Gunnison and Garfield counties, and of the building of the Aspen and Western railroad to the coal-mines of that com- pany. In 1885 he and his associates established at Florence, Colo., the Florence Oil and Refining Co., one of the earliest rep- resentatives in the State of that productive and useful industry. About 1892, induced by the dawning importance of the Cripple Creek district, he conceived the plan of the Florence and Cripple Creek railway — a line, forty miles long, which involved great engineering difficulties, but, once constructed, became, and has remained ever since, one of the most profitable, in pro- portion to its length, in the world. In these and other like enterprises in railway-building, mining, smelting, etc., he accumulated an ample fortune for himself, and, at the same time contributed greatly to the development of the mineral resources of his adopted State, in which he cherished an en- thusiastic faith.

Walter J. Koehler died from heart-failure on the 24th of

Pbocbbdikgs Of New York Mbeting. Xxix

April, 1901, at the Bellevue mine, Mount Sir Samuel, West Aastralia. He was graduated from the Massachusetts Institute of Technology, Boston, Mass., in 1881, with the degree of S.B.,. and for two years thereafter was chemist of the Pueblo Smelt- ing and Refining Co., Pueblo, Colo. In 1888 he became assistant metallurgist of the same company. From 1885 to 1888 Mr. Koehler was employed by the Graphite Mining and Smelting Company of Socorro, N. M., and at Parral, Chihuahua,, Mex, In 1888 he went to Broken Hill, New South Wales, as assistant superintendent of the smelting-works of the Broken: Hill Proprietary Co., and became successively assistant, and: afterwards chief metallurgist, of that company. During 1899,. 1900 and 1901 he was general manager of the Western Aus- tralian Smelting Co. at Preemantle, and afterwards at Beacons- field. At the time of his death he was interested in the treat- ment of the complex gold-ores of the Bellevue mine at Mt Sir Samuel, West Australia.

Charles A. Macy 2d, born at New York City in 1874, be- came an associate of the Institute in 1894, while still an under- graduate student at the Columbia School of Mines in New York. By reason of impaired health, he did not graduate in 1895 with hifl class, but subsequently received in 1899 his de- gree as mining engineer, and in that year became a member of the Institute. Unfortunately, he never recovered his strength, and, after years vainly spent for this purpose in travel and rest, he died August 28, 1901, without having fulfilled by actual achievements the promise of his youth.

Thomas S. McNair, born 1824, in Hanover, Pa., studied at Williams College, Mass., and subsequently taught school for a number of years, but ultimately adopted the profession of en- gineering- He was connected with the construction of the Raritan and Passaic Canal from Easton to Perth Amboy ; was assistant division-engineer under W. F. Shunk (one of the most famous men of his time in that line) in the building of the North Penn railroad between Bethlehem and Philadelphia; and was also employed as an engineer in the construction of the Lehigh canal.

About 1854, while still a young man, he made Beaver Meadow, Pa., his residence. Somewhat later, together with

Xxx Proceedings Of New Tork Meeting.

the late W. R. Maffet, he built that part of the North Branch canal which, extending from Wilkes-Barre to the New York boundary, was subsequently transferred to the Lehigh Valley Railroad Co., and abandoned. Many such early internal water- ways have long since become of subordinate importance, or have disappeared altogether, in competition with later means of transportation. But in their time they aided mightily in the commercial development of the country; and their constructors were the leaders of American engineering.

A little later, Mr. McNair moved to Hazleton, Pa., where he resided until his death on July 26, 1901. The occasion of this change was his acceptance of the position of chief engineer of the Hazleton, subsequently merged into the Lehigh Valley, railroad. Under both administrations, he retained his position until 1898. Under his direction the tunnel between Hazleton and Jeddo and the link between Hazleton and Pottsville were constructed. The Harleigh canal and the famous Jeddo tun- nel are witnesses of his skill as an engineer. He became, in 1871, and remained until his death, a member of the Institute.

Jarnes E. Mills was born in Bangor, Me., February 13, 1834, and died July 25, 1901, at San Fernando, Durango, Mexico. At the age of eighteen he went to Cambridge, Mass., and spent six years in the Lawrence Scientific School of Harvard Univer- sity, where, after taking his degree as Bachelor of Science, he became an assistant in the laboratory of Prof. Agassiz. Here he met Joseph Le Conte, who just preceded him in graduation from the scientific school. Subsequently, at the suggestion of Agassiz, he made a careful geological survey of the Sierra Ne- vada in Plumas county, Cal. ; and the results of his labor exist in accurate detailed maps, showing the formation of the Sierra, the changes of its water-courses, and the causes therefor. He was connected until his death with various mining interests ; and his last work was the development of the great gold-mine at San Fernando, in Durango, Mex., and the design and con- struction of one of the most perfect milling-plants of its size in the world. At the time of his death he was, as he had been since 1895, consulting geologist of the Anglo-Mexican Min- ing Co.

Samuel Fisher Morris born at Pottsville, Pa., in 1848, was a lineal descendant of Robert Morris, the eminent financier of

Progsbdings Of Nbw York Meeting. Xxxi

the American Revolationary period, and belonged to a family closely connected, during following periods, with the mining ftod iron industries. It was therefore natural that he should adopt engineering as a profession, and associate himself with various enterprises directed to the development of the mineral resources of the United States. He was at one time superin- tendent of the mines and furnaces at Quinnimont, W. Ya., sod, somewhat later, an assistant of Mr. J. H. Bramwell in the important and fruitful pioneer work with which Mr. Bram well's Dame is associated. For some years he was an engineer of the New Croton Aqueduct Commission of New York.

Mr. Morris was honored at different times by difterent gov- ernors of West Yirginia with appointment as a member of public commissions requiring professional knowledge and practical judgment. He was an intelligent and fluent writer, and contributed, in 1880, to the Transactions of the Institute an able paper on the " New River Coal Field of West Yirginia." At the time of his death, from heart-failure, which occurred June 13, 1901, at Eckman, W. Ya., he was superintendent of the mines of the Pulaski Iron Co. of that place. Mr. Morris was universally esteemed as an engineer of accomplished skill, wide experience and absolute integrity.

Frank Owen was born at London, Eng., in 1869. He re- ceived his early education at the Whitgift School, Croyden, Surrey, and later he attended the Royal School of Mines, Lon- don, graduating therefrom in 1889. His first professional work was at the Frontino and Bolivia mines, near Remedies, Anti- oqoa, Colombia ; he then went to the El Callao mines, Yene- zuela, and remained there several years. He then returned to England, and subsequently was engaged in the examination of mining properties in South Africa, West Australia, Siam, Straits Settlements, Norway, Spain and the United States. In November, 1900, Mr. Owen took charge of an expedition to ex- plore for gold in West Africa, and shortly after his arrival at Gold Coast he contracted a fatal illness, and died on July 13, 1901. His contributions to the TVansationSj though only in the way of discussion of the papers of other authors, were both versatile and valuable, as the following list of subjects will in- dicate: Accumulation of Amalgam on Copper Plates (xxvi., 1049); Mining in Colombia (xxviii., 804) ; Mines of the Fron-

XXXll PROCEEDINGS OF NEW YORK MEETING.

tino & Bolivia Co. (xxviii., 908) ; Equipment of Camps and Ex- peditions (xxix.,, 1030); Evolution of Mine-Surveying Instru- ments (xxx., 795). He wrote also for the IXth volume of The Mineral Industry a very thorough and able review of the Tin Industry of the Malay Peninsula, to the end of 1899.

Edward Walsh Jr., born in 1849, died in 1901, en route from his home in St. Louis, Mo., to the Hot Springs of Virginia. At the time of his death he was one of the leading citizens of St. Louis, President of the Mississippi Glass Works, and con- nected as officer or director with numerous social or commer- cial organizations. At one time he had served his city as Water Commissioner.

Mr. Walsh became a member of the Institute in 1874, at which time he was specially interested in the manufacture of charcoal-iron. At the St. Louis meeting, October, 1886, he presented an elaborate and important paper* on " The Irregu- larities of the Blast-Furnace Process, and the Best Way to Avoid Them," to which he added, at the New York meeting, February, 1889, a " Supplementary Note on Blast-Furnace Lines.'' These papers must be ranked among the most credit- able of the contributions to the metallurgy of iron (or, more precisely, to the theory and practice of the iron blastfurnace) elicited from American sources by the scientific treatises of Lowthian Bell and other authorities. They evince a famil- iarity with the literature of the subject, as well as the details of actual practice ; and, although the later blast-furnace prac- tice, with its immensely increased dimensions of stack, pres- sure and temperature of blast, speed of smelting, and conse- quent amount of daily product, has radically changed both the problems and the factors with which Bell and his pupils and critics had to deal, these papers, like others of their kind to be found in our TVansaxitions for that period, are still worthy to be studied as specimens of the scientific method, candid temper, patient industry and spirit of hearty co-operation with which, in every epoch of technical progress, the pregnant questions o'f that epoch can be most fruitfully handled. In the manufacture of glass, to which Mr. Walsh, during later years, contributed much of his time and scientific and administrative ability, he

!ZVafM., XT., 419.

PBOCBEBINOS OF NEW TOBK MBBTING. XXXlll

evinced the same personal qualities and powers. The works with which he was connected were among the first to practice the making of glass in gas-heated reverberatories, substituting buge hearths for crucibles; and they remained to the last models of modern method and construction.

The following papers were read by title, for subsequent pub- lication and discussion :

Diatom-Earth in Arizona, by William P. Blake, Tucson, Ari- zona.

The Auditing of a Mining Company's Accounts, by Charles V. Jenkins, Kossland, British Columbia.

Notes on Brazilian Gold Ores, by Orville A. Derby, Sao Panio, Brazil.

Truck-Support for Furnace-Bottoms, by Henry A. Mather, New York City.

The Camp Bird Mine, Ouray, Colorado, and the Mining and Milling of the Ore, by C. W. Purington, Thos. H. Woods and Godfrey D. Doveton, Ouray, Colo.

Basaltic Zones as Guides to Ore-Deposits in the Cripple Creek District, Colorado, by E. A. Stevens, Victor, Colo.

A Consideration of Igneous Rocks and their Segregation or Differentiation as Related to the Occurrence of Ores, by Joeiah Edward Spurr, Constantinople, Turkey.

The Mining Industry of the Coeur d'Alenes, Idaho, by Jame& Ralph Finlay, Colorado Springs, Colo.

The Tombstone, Arizona, Mining District, by John A. Church, New York City.

Notes on the Cost of Hydraulic Mining in California, by W. E. Thome, Georgetown, Cal.

The Original Southern Limit of the Pennsylvania Anthra- cite-Beds, by Benjamin Smith Lyman, Philadelphia, Pa.

Determining Size of Hoisting-Plants, by Edward B. Dur- ham, Trenton, N. J.

Further Discussion of Scott's paper on The Evolution of Mine-Surveying Instruments, by E. A. H. Tays and Bennett H. Brough.

A notice of an amendment to the rules was offered as follows :

Rule in., Paragraph III., to read : " Any Member or Asso-

Proceedings Of New Yore Meeting.

ciate, not in arrears, may become, by the payment of (150.00 at one time, a Life-Member or Life-Associate, and shall not be liable thereafter to any dues."

This amendment changes the amount from $100.00 to (150.00. It will be presented at the annual meeting in February, 1903 for discussion and adoption, subject to a subsequent vote of the members and associates of the Institute by postal ballot.

The Scrutineers, appointed for this purpose under Rule V., reported that the following officers had been elected :

PRESIDENT. E. E. Olcott, New York City.

VICE-PRESIDENTS, (To serve two years.)

S. F. Emmons, Washington, D. C.

James Gayley, Pittsburg, Pa.

J. Henby Lee, Carbon Hill, Ala.

MANAGERS, (To serve three years.)

E. W. Pabkeb, New York City.

James W. Neill, Salt Lake City, Utah.

M. D. Valentine, Woodbridge, N. J.

TREASURER. Theodore D. Band, Philadelphia, Pa.

SECRETARY. BossiTEB W. Raymond, New York City.

The session was then adjourned, with the understanding that the meeting would be continued by further sessions at Philadelphia, Pa., in accordance with official notice to be given later.

Proceedings of the Eighty-Second Meeting, Part II., Philadelphia, May, 1902.

Local GmuniUee.— John Birkinbine, Chairman; Edward H. Sanborn, Secretary; George F. Baer, Cyrus Borgner, Arthur Brock, Theron I. Crane, George DaTis, James M. Dodge, Theo. N. Ely, R C. Felton, F. Lynwood Garrison, H. L Haldeman, E. V. IVInvilliers, Jawood Lnkens, E. H. McCullough, Henry G. ilorris, Henry G. Morse, T. D. Band, Percival Roberts, Jr., P. G. Salom, Bichard H. Sanders, C. R Stafford, Henry T. Townsend, S. M. Yaaclain, John P. WetherUl, Walter Wood.

Ofaal Headquarter* and Bureau of Information. — The Manufacturers' Club, 1409 Walnut Street

Hotd-JTeadquariersi. — The Hotel Walton, Broad and Locust Streets.

Thk first session was held at the Manufacturers' Club on Tuesday afternoon, May 13th. After a brief address of wel- come by Mr. Birkinbine, Chairman of the Local Committee, and an appropriate reply by President Olcott, the following paper was presented by title to be read in full at the next meeting.

Biographical Notice of Clarence King, by R. W. Raymond, James T. Gardiner, S. F. Emmons and James D. Hague.

This paper being still incomplete, Dr. Raymond accompanied the reading of the title with remarks and interesting anecdotes concerning Mr. King.

The following papers were presented by their authors, in oral abstract, accompanied with numerous lantern-illustrations :

The Use of Ordinary Cameras in Accurate Photographic Surveying, by Howard W, DuBois, Philadelphia.*

Puddled Iron and Mechanical Means for its Production, by James P. Roe, Pottstown, Pa.

The second session was held Tuesday evening. May 13th, at the same place.

President E. E. Olcott delivered the Presidential Address.

The following paper was presented by the author, in oral abstract, accompanied with numerous lantern-illustrations :

The Cement Industry of the United States, by Richard L. Humphrey, Philadelphia.*

Not furnished for publication.

XXXVl PROCEEDINGS OF PHILADELPHIA MEETING.

The third session — a joint session of the Institute and the Mining and Metallurgical Section of the Franklin Institute of Philadelphia, Mr. P. Lynwood Garrison, Chairman of the said Section, presiding — was held Wednesday evening. May 14th, at the same place.

The following papers were presented by their authors, in oral abstract, accompanied with numerous lantern-illustra- tions:*

Presented to this Institute :

The Development of the Bessemer Process for Small Charges, by Bradley Stoughton, Columbia University, New York City.

Presented to the Franklin Institute :

Steel Rails : Relations Between Structure and Durability, by Robert Job, Chemist for the Philadelphia and Reading Railway Company, Reading, Pa.t

The following papers were read by title :

(JFbr the Franklin Institute.) The Beaumont Oil-Field, with Notes on Other Oil-Fields of the Texas Region, by Robert T. Hill, Washington, D. C.

The Metallurgy of Titanium, by Auguste J. Rossi, New York City.

{For the Institute of Mining Engineers,)

Growth of the Pig-iron Production during the Past Thirty Years, by John Birkinbine, Philadelphia, Pa.t

The Effect of Re-Heating Upon the Coarse Structure of Over-Heated Steel, by Karl F. Goransson, Sandviken, Sweden.

The fourth session, held at the Manufacturers' Club, Thurs- day forenoon. May 15th, was devoted to a discussion of specifi- cations for steel rails, forgings and castings, with reference to papers read at previous sessions, and the following, presented in print on this occasion :

Specifications for Steel Forgings and Steel Castings, by Wil- liam R. Webster, Philadelphia, Pa.

The Present Situation as to the Specifications for Steel Rails, by William R. Webster, Philadelphia, Pa.

By agreement of the two societies, each was authorized to publish in whole or in part, any of the papers presented to the other society at this session. t Not furnished for publication.

PROCEEDINGS OF PHILADELPHIA MEETING. XXXVll

Bemarks were made by Messrs. H. H. Campbell, Robert Job, William R. Webster, C. B. Dudley, William Kent, Gus C. Hen- ning. Prof. G. Lanza and R. W. Raymond.

The fifth and final session was held in Houston Hall, at the University of Pennsylvania, Thursday afternoon. Dr. Edgar F. Smith, Vice-Provost of the University, in a felicitous and in- teresting address, welcomed the visiting members, and indicated the various departments, museums, etc., of special interest to them, which were open to their inspection. In the absence of President Olcott, Mr. E". V. D'Invilliers, Vice-President of the histitute, made a suitable response, and took the chair for the ensuing session. The following papers were read by their authors, and discussed :

Gold-Mining in McDuflie County, Georgia, by W. H. Fluker, Tatham, Ga.

Principles Controlling the Geologic Deposition of the Hydro- Carbons, by George I. Adams, Washington, D. C.

The following paper was presented in print by the Secretary, in the absence of the author, and discussed :

The Mineral Crest, or the Hydrostatic Level Attained by the Ore-Depositing Solutions in Certain Mining Districts of the Great Salt Lake Basin, by Walter P. Jenney, Salt Lake City, Utah.

The following papers, not mentioned above, were read by title for future publication and discussion :

The Calculation of the Weights of Castings with the Aid of the Planimeter, by Clarence M. Schwerin, New York City.

Silver-Mining and Smelting in Mongolia, by Yang Tsang Woo, Tong Shan, China.

The Gold-Field of the State of Minas Geraes, Brazil, by Herbert Kilburn Scott, London, England.

The Reactions in the Ziervogel Process and their Tempera- ture-Limits, by Robert Henry Bradford, New York City.

The Effect of Tellurium on Brass, by E. S. Sperry, Bridge- port, Conn.

Procbedinqs Of Philadelphia Mebtino.

Members and Associates Elected.

The following persons were elected members or associates by postal ballots of January 18, April 2, and April 80, 1902.

Honorary Members.

Dimitry CoDstantine TschemofiF, Manael Maria Gontreras,

St Petersburg, Russia. Mexico City, Mexico.

Members.

Thomas Adams, . Harry W. Althouse, Edward Bailey, . Dudley fiaird, James H. Baker, . JosBalta, . Henry A. Barren, J. Mackintosh Bell, John Bermingham, Jr., S. Haldeman Bigler, Thomas O. Bishop, Edwin W. Bonwick, Cyrus Borgner, . Anton Bosch, Francis W. Bosoo, Herbert Bottomly, James K Bowden, William S. Boyd, John Boyt, . R H. Bradford, . R J. Bradley, Walter W. Bradley, Frederick Bradshaw, R D. Bushnell, . William A. Caldecott, John R Carey, . Wayne Choate, Burton I. Ceilings, JayA.Czizek, Albert C. Dart, Jr., Orville A. Derby, Herald Thomas Dickinson, Ambrose A. Diehl, Cleveland H. Dodge, R)ger H. Downer, Gustavus A. Duncan, Henry Thomas Durant, William Durbrow, Howard Eckfeldt, Walter L. Ehrich,

New York City, N. Y. Potteville, Pa. Harrisburg, Pa. Campo Seco, Cal. Steeple Bock, N. M. Lima, Peru, So. Am. Cleveland, Ohio. Ottawa, Canada. Pinole, Cal. Kobesonia, Pa. Wellington, New Zealand. Auckland, New Zealand. Philadelphia, Pa. Berlin, Germany. Denver, Colo. Johannesburg, So. Africa. Idaho Springs, Colo. New Castle, New So. Wales. La Follette, Tenn. New York aty. Auckland, New Zealand. Robinsons, Cal. Chihuahua, Mexico. Telluride, Colo. Johannesburg, So. Africa. Chihuahua, Mexico. Detroit, Mich. London, England. Salt Lake City, Utah. Idaho Springs, Colo. Sao Paulo, Brazil, So. Am. Kimberley, So. Africa. Duquesne, Pa. New York City. Ouray, Colo. Salt Lake City, Utah. Dayton, Nevada. San Francisco, Cal. Bethlehem, Pa. Colorado Springs, Colo.

Pboceedings Of Philadelphia Meeting.

iryxiy

a B. Elbert, Hugh F. E]lard, . Alan J. FairiMdm, Wilfrid B. Field, . Fernando Carlos Fuchs, Jesos de la Fuente, A. de Gennes, Henderson Gilbert, William A. Groodspeed, William H. Gregson, . James William Hambleton, H. W. Haidinge, Willaid F. Harris, W. & Harvey, . J. E. Haverstick, Frederick W. Hoar, . F J. Hobson, James S. Hollings, Taylor Holt, James F. Hopkins, Edwin F. Houston, Charles £. Holick, Arthar Curtis James, . Frank W. Janes, . Arthar Jarman, . Thomas H. Jenks, Archibald Johnston, . Wayerley Keeling, Alexander G. Keiller, . George A. Kennedy, . Jeremiah Joseph Kennedy, Joseph F. Kent, . Austin J. King, . Kuneon T. Kochkine, . Jerome Baker Landfield, William Lander, . Alexander Leggat, Edward M. Lengle, Hamilton Lindsay, Michael E MacDonald, Max McMorray, . Herbert H. McNamam, James S. Mann, . Herman Mattem, E. A. Merton, Darid Irving Miller, . Philip Mixsell, . Ambrose Monell, . Charles K. Murdoch, . fiobert Balfonr Nicholson, WUtcm Landis Oglesby,

Idaho Springs, Colo.

Ironwood, Mich.

Denver, Colo. . New York City.

Lima, Pern, So. America.

Madadores, Coahuila, Mexico.

Paris, France.

Harrisburg, Pa. . Longacre, W. Va. . New Castle, New South Wales. . Mexico City, Mexico. . Denver, Colo. . Ouray, Colo. . Phihidelphia, Pa. . Philadelphia, Pa. . Globe, Arizona. . Mexico City, Mexico. . Brymbo, North Wales. . Sombrerete, Zacatecas, Mexico.

Parral, Mexico. . Philadelphia, Pa. . Easton, Pa. . New York Qty.

Melbourne, Australia. . Sydney, New South Wales. . Albuquerque, N. M.

Bethlehem, Pa.

Juneau, Alaska.

Denver, Colo.

Silverton, Colo. . New York Qty.

Horr, Mont

Pocahontas, Va.

Kostow-on-the-Don, So. Russia. . Bingham pton, N. Y.

Biddlesburg, Pa. . Butte, Mont. . New York City. . Sault Ste. Marie, Ontario. . New York City. . Cleveland, Ohio.

Duluth, Minn. . Tucson, Arizona. . Hombrook, Cal. . Santiago, Dnrango, Mexico. . Sheffield, Ala. . Denver, Colo. . Pitteburg, Pa. . Contact, Montana.

Boulder, West Australia. . Bobinson's, Utah.

Procebdinqs Of Philadelphia Meeting.

Edwin L. Oliver, . Alexander Orr, Willard J. Parker, Frederick M. Paasow, John C. Percy, Arthar Philbrick, Clement EL Pollen, Augustus L. J. Queneau, Ivan Ragaz, Huntley B. S. Randall, Albert M. Bedfearn, Edward J. Roberts, Francis W. Scarborough, F. Schniewind, Herman Otto Schulze, Clarence £. Schwartz, Linn W. Searles, . Joseph B. Settle, . William Llewellyn Shaffer, Harry J. Sheafe, . William McG. Shins, Frederick S. Shirley, Gilbert C. Simpson, J. C. Skinner, George Otis Smith, Egbert Smit, Louis A. Stadtler, Robert G. Stanley, Robert Sterling, . Gerald B. Street, . Ernest A. Strout, . Alan Sullivan, H. N. Tod, . W. H. Tomlinson, John Treweek, Nat. Tyler, Jr., . Titus Ulke, . George D. Van Arsdale. Walter H. Virgoe, H. R Wagner, . Albert M. Walsh, George J. Wanless, Bruce R Warden, William J. Weatherby, Utley Wedge, James Walker Wells, Shelton Ring Wheeler, €k)rdon Wilson, .

. Oakland, CaL

Sydney, New South Wales.

Mexico City, Mexico. . Santa Rita, Mexico.

. Wheeling, W. Va.

Portland, Oregon.

. Fort Steele, B. C, Canada. . New York City.

Sierra Mojada, Mexico.

Monterey, Mexico. . Sultepec-Mexico, Mexico.

Spokane, Wash.

Richmond, Va. . New York Qty. . Rolla, Mo. . Desloge, Mo. . La FoUette, Tenn. . London, England. . Idaho Springs, Colo. . Seattle, Wash. . Pittsburg, Pa.

Buckingham, Queensland, Aost. . Chihuahua, Mexico. . Denver, Colo. . Washington, D. C. . Guanajuato, Mexico.

Butte, Mont. . New Brighton, N. Y.

Wardner, Idaho. . Salt Lake City, Utah. . Rossland, B. C. . Port Arthur, Ontario, Canada. . Denver, Colo.

Sault Ste. Marie, Ontario, Can. . Salt Lake City, Utah. . Washington, D. C.

Sault Ste. Marie, Ontario, Can. . New York City.

Mexico City, Mexico. . Denver, Colo.

Amador City, Cal. . El Paso, Tex. . Ferguson, B. C, Canada. . Cooney, N. M. . New York City.

Belleville, Ontario, Canada. . New York City. . Mexico City, Mexico.

PROCEEDINQS OF PHILADELPHIA MEETING. xU

Associates.

Henry Thornton Bowles, Walter aLysle, . Heginald Meeks, . Myron A. Pattiaon, James L. Robertson, Cbas. B. Van Nostrand, L. Webster Wickes, . Francis & Yoang,

New York City. New York City. New York City. New York City. Kobe, Japan. New York City. New York City. Boston, Mass.

Change of Status, from Associate to Member.

Theodore Dwight, . . New York City.

Charles W. Howard, Jr., . Spencevilie, Cal.

L, H. Taylor, Jr., . . . Philadelphia, Pa.

Excursions and Entertainments.

The session of Tuesday evening was followed by a " Camp- fire of Veterans," at which Dr. T. M. Drown and Mr. E. C. Pechin gave entertaining reminiscences of the early days of the Institute, and President Olcott, himself a " veteran " (hav- ing joined the Institute in 1874), made, upon request, a few remarks concerning the island of Martinique, which he had visited, and the city of St. Pierre, the recent awful destruction of which, by a volcanic eruption from Mt. Pelee, was engrossing the sympathies of all. A most picturesque and pathetic touch in this description deserves to be recorded, namely, Mr. Olcott's mention of the fact that each of the gaily-dressed native women of St Pierre, in accordance with a sentiment universal among them, wore, in the form of ear-rings or necklace, ornaments of sufficient value to pay for her suitable burial. The contrast between this pious forethought and the tragic death and burial of all these simple daughters of the doomed island needed no comment.

The proceedings of the " Camp-fire " might have lasted mach longer, to the interest and profit of the crowded audi- ence, but for the superabundant provision for entertainment made by the Local Committee. It seems to have been expected that, while the " veterans " were talking, the younger members and guests would amuse themselves in the ball-room, or in par- taking refreshments. But the young ones liked too well to listen to the old ones ; orchestra and ice-cream pleaded, the one melodiously and the other dumbly, but both in vain ; and at

Xlii PROCBEDINQS OF PHILADELPHIA MEETING.

last the veterans were forced to adjourn, in order to save the rest of the programme from destruction. However, it is said to be the highest art to stop when everybody wishes to go on ; and, measured by this standard, the " Camp-fire " was a triumph of good management

Wednesday, May 14th, was spent in an excursion to the Edison Cement Works, near Philipsburg, N. J. A special train, furnished by the Pennsylvania R. R. Co., left Philadel- phia at 9 A.M., and proceeded, via Trenton and the Belvidere Division, to Philipsburg, where it was transferred to the track of the Delaware, Lackawanna and Western R. R., and hauled to the works of the Cement Company. The plant was not yet in regular operation; but parts of it were operated for the information of the visitors, who inspected with much interest the ingenious and elaborate machinery for crushing, conveying, calcining and handling crude material and product. Refresh- ments were served in one of the new buildings.

Thursday afternoon. May 15th, before the session, a luncheon was given to the members and guests of the Institute, at the Houston Club, University of Pennsylvania. After the session, the library, museums and laboratories (including especially the engineering laboratory and the new Morgan physical labora- tory), the Botanical Garden, Aquaria, and other departments of the University, were inspected with great interest and pleasure.

Thursday evening. May 15th, a reception to the oflBcers, vis- iting members and guests of the Institute was given by the Local Committee at the Academy of the Fine Arts. The magnificent staircases, halls, rooms and picture-galleries of the Academy are peculiarly adapted for such entertainments ; and the occasion, graced by the presence of many eminent repre- sentatives of the science and society of Philadelphia (including numerous ladies), was brilliantly picturesque, as well as thor- oughly delightful. As may be inferred from the registry given below, the attendance of members and guests, and of the ladies accompanying them, was exceptionally large, and justified, by its numbers, character and cordial enthusiasm, the signal social recognition and entertainment provided in this reception.

Friday was devoted to an excursion on the Delaware river, including visits to the famous ship-yard of the William Cramp

PROCEEDINGS OF PHILADELPHIA MEETING. xliii

t Sons* Ship- and Engine-Building Co., the new yard and plant of the New York Ship-Building Co., and the League Island U. S. Navy-yard. The intensely interesting nature of these professional inspections was supplemented by a planked-shad " Inncheon at Washington Park, on the Delaware, and the de- fights of the day were crowned with balmy weather. Indeed, the whole week of the meeting was signally blest in this re- spect

Besides the formal excursions and entertainments recorded above, visiting members were, individually and collectively, the recipients of numerous invitations and courtesies from the in- stitations, clubs, societies, manufacturers and citizens of Phila- delphia, which contributed not a little to their comfort and eDJoyment.

Members and Guests Registered.

The following persons, together with about one hundred ladies accompanying them, were registered at headquarters :

Greorge I. Adams, Washington, D. C.

Taylor Alderdice, Pittsburg, Pa.

Bobert Allison, Port Carbon, Pa.

W. S. Ayres, Hazleton, Pa.

F. E Bachman, Port Henry, N. Y.

Stephen Badlam, Bteelton, Pa.

Geo. F. Baer, Philadelphia.

B, N. Bailey, Philadelphia.

Chester S. Batchelder, Spokane, Wash.

Ir?ing M. Bean, Milwaukee, Wis.

Lodns S. Bigelow, New York City.

John Birkinbine, Philadelphia.

Cyras Borgner, Philadelphia.

James Bowron, Birmingham, Ala.

a A. Bragg, Philadelphia.

Samuel D. Bridge, Monterey, Mex.

Arthur Brock, Philadelphia.

Albert Broden, Beading, Pa.

Bichard T. Brooks, Swarthmore, Pa.

Amoe P. Brown, Philadelphia.

Wm. Bumham, Philadelphia.

H. H. Campbell, Steelton, Pa.

J. A. Oeipp, Schenectady, N. Y.

G. H. darner, Philadelphia.

Edward T. Clymer, Philadelphia.

William J. Coane, Philadelphia.

Albert Ladd Colby, South Bethlehem, Pa.

Verplanck Colvin, Albany, N. Y.

0. L Conlcy, New York Ciij.

Xliv PROCEEDINGS OF PHILADELPHIA MEETING.

Torbert CJoryell, Lambertville, N. J.

Theron I. Crane, Philadelphia.

Q. C, Crawford, McKeesport, Pa.

J. D. Darling, Philadelphia.

George C. Davis, Philadelphia.

David T. Day, Washington, D. C

W. S. De Qimp, New York City.

J. H. Devereux, Aspen, Colo.

Edward V. D'lnvilliers, Philadelphia.

James M. Dodge, Philadelphia.

Thomas M. Drown, South Bethlehem, Pa.

Howard W. DuBois, Philadelphia.

Charles B. Dudley, Altoona, Pa.

A. J. Dull, Harrisburg, Pa.

Edward B. Durham, . . . . . Trenton, N. J.

Theodore Dwight, New York City.

Thomas A. Edison, Orange, N. J.

A. EileFS, Brooklyn, N. Y.

Theodore N. Ely, Philadelphia.

Arthur Henry Eyles, Addingham, Pa.

Thomas W. Eynon, Philadelphia.

B. F. Fackenthal, Jr., Biegelsville, Pa.

S. E. Fairchild, Jr., Philadelphia.

Albert H. Fay, New York City.

Edgar C. Felton, Philadelphia.

Thomas Fisher, Philadelphia.

J. M. Fitzgerald, . . . . . Catasauqua, Pa.

W. H. Fluker, Tatham Mines, (Ja.

Stanton S. Freeman, Parryville, Pa.

Edmund L. French, Syracuse, N. Y.

F. Lynwood Garrison, Philadelphia. Horace L. Haldeman, Philadelphia.

G. W. Hamilton, Philadelphia.

Joseph Hartshorne, Pottstown, Pa.

J. E. Haverstick, Philadelphia.

G. C. Henning, New York City.

A. C. Higgins, Worcester, Mass.

Thos. Hobson, Philadelphia.

W. Hochschild, Mexico City, Mexico.

Willard C. Hosbach, Philadelphia.

Edwin J. Houston, Philadelphia.

George S. Humphrey, New York City.

W. S. Hungerford, Jersey City, N. J.

O. A. Ihlseng, Carthage, Mo.

Wm. A. Ingham, Philadelphia.

Waller M. James, Philadelphia.

George N. Jepson, Worcester, Mass.

Bichard M. Jesup, New York City.

W. J. Johnston, New York City.

Washington Jones, Philadelphia.

F. J. Keeley, Philadelphia.

H. A. Keller, San Francisco, Cal.

PROCEEDINGS OF PHILADELPHIA MEETING. xlv

John S. Kennedy, Stanhope, N. J.

Jnlian Kennedy, Pittsburg, Pa.

William Kent, Passaic, N. J.

Thos. M. King New York City.

Charles Kirohhoff, New York City.

6. F. Knapp, Cleveland, Ohio.

Fletcher H. Knight, Hokendauqoa, Pa.

Edward K. Landis, Philadelphia.

H. M. Lane, Scranton, Pa.

I. H. Lee, Baltimore, Md.

N. Llllienberg, Philadelphia.

John Lilly, Lambertville, N. J.

R C Lindsay Philadelphia.

W, W. Lindsay, Philadelphia.

A. F. Lncas, Washington, D. C.

A. F. Lucas, Jr., Washington, D. C.

Jawood Lukens, Conshohocken, Pa.

Benj. Smith Lyman, Philadelphia.

W. H. McCallum, Philadelphia.

Henry McCormick, Jr., . . . Harrisburg, Pa.

A. S. M'Creath, Harrisburg, Pa.

Leslie M'Creath, Harrisburg, Pa.

Edmund H. McCullough, Philndelphia.

John McLeavY, Punxsutawney, Pa.

Simon & Martin, Sparrow's Point, Md.

Chas. A. Matham, . ' . . . AUentown, Pa.

E. P. Mathewson, Montreal, Can.

Chas. C. Mattes, Scranton, Pa.

W. F. Mattes, Scranton, Pa.

DeCoursey May, Philadelphia.

August A. Miller, Philadelphia.

Fred J. MUler, New York City.

Bobert Mitchell, Philadelphia.

Richaixl G. G. Moldenke, New York City.

A. S. Morris, Philadelphia.

Henry G. Morris, Philadelphia.

William H. Morris, Philadelphia.

Edwin Morrison, Addingham, Pa.

Henry G. Morse, Camden, N. J.

Wm. G. Neillson, Philadelphia.

E. R Olcott, New York City.

George Ormrod, A Hen town, Pa.

R R Patterson, Philadelphia.

Edirard W. Parker, New York City.

D. M. Parry, Indianapolis, Ind.

Edmund C. Pechin, Torega, Va.

D. D. Pendleton, Pittsburg, Pa.

lUchard Peters, Jr., Chester, Pa.

Stephen Minot Pitman, Providence, R. I.

J. Wesley Pullman, Philadelphia.

A. Raht, Salt Lake City, Utah.

Theodore D. Rand, Radnor, Pa.

Xlvi PROCEEDINGS OF PHILADELPHIA MEETING.

R. W. Raymond, Brooklyn, N. Y.

M. Alton Richards, South Bethlehem, Pa.

William H. Richmond, Scranton, Pa.

T. A. Rickard, Denver, Colo.

Wm. Barrett Ridgley Washington, D. C.

C. O. Ripley,

Percival Roberts, Jr., Philadelphia.

James P. Roe, Pottstown, Pa.

C. W. Roepper, Philadelphia.

Pedro G. Salom, Philadelphia.

Edward H. Sanborn, Philadelphia.

Richard H. Sanders, Piiiladelphia.

H. J. Seaman, Catasauqua, Pa.

Charles Schaffer, Philadelphia.

E. J. Schmitz, New York City.

H. H. Seabrooke, Washington, D. C.

Fred H. Sharpless, Philadelphia.

J. M. Sherrerd, High Bridge, N. J.

H. E. Smith, Milwaukee, Wis.

Oberlin Smith, Bridgeton, N. J.

Percival H. Smith, Bridgeton, N. J.

T. Guilford Smith, Buffalo, N. Y.

George E. Somers, Bridgeport, Conn.

Erwin S. Sperry, Bridgeport, Conn.

C. Edward Stafford, Chester, Pa.

W. M. Stein, Philadelphia.

Bradley Stoughton, New York City.

Knox Taylor, Bound Brook, N. J.

L. H. Taylor, Jr., Philadelphia.

W. J. Taylor, Bound Brook, N. J.

George E. Thackray, Johnstown, Pa.

Edwin Thomas, CatasMuqua, Pa.

H. G. Torrey, New York City.

Henry T. Townsend, Philadelphia.

S. W. Traylor, New York City.

Samuel M. Vauclain, Philadelphia.

John A. Walker, Jersey City, N. J.

Willard P. Ward, New York City.

Wm. R. Webster, Philadelphia.

John Price Wetherill, . . . . Philadelphia.

S. Bowman Wheeler, Philadelphia.

George A. White, New York City.

Maunsel White, Bethlehem, Pa.

John F. Wilcox, Cleveland, O.

William H. Wiley, New York City.

Oliver Williams, Catasauqua, Pa.

Frank S. Witherbee, New York City.

Walter Wood, Philadelphia.

H. H. Yard, Philadelphia.

James E. York, Brooklyn, N. Y.

Frank M. Zeller, Philadelphia.

p-occcdiogs of the Eighty-Third Meeting, New Haven,

. V. T'lTsaon, Profeasor of Physical Geology, Secretary ; W. H. Brewer, of Agi<5uUure;C. E. Beecher, Profeasor of Paleontology; F. L. Bige- p!ident of the BigeW Boiler Works ; Theodore A. Blake ; Wm. P. Blake, low, School of Mines, University of Arizona ; G. J. Brush, Professor of Emeritus ; A. J. DuBois, Professor of Civil Engineering ; H. W.

Mioerft of PoUUcal Economy ; H. E. Gregory, Assistant Professor of VeasoT of Physics; 8. L, Fenfield, Professor of Mineralogy ; J. K. Pun- -d'Eogin'" Haven and Westville Electric Railway Co. ; C. B. derfo T feeaoT of Mechanical Engineering ; H. B. Sargent, Vice-President HichftTd -

Xc

Thb session was held Tuesday evening, October 14th. THrector K- H. Chittenden of the Sheffield Scientific School, as hairnian of the Local Committee, called the meeting to order, aod after a few words of greeting, introduced Arthur T. Had- lev lAj'T-y President of Yale University, who delivered an ad- dress of cordial welcome, to which President E. E. Olcott of the Institute made an appropriate reply, making incidental ref- erence to the brief visit of the Institute to New Haven (in con- nection with the Bridgeport meeting of October, 1894). The Secretary added some reminiscences of the meeting of the Institute, held at New Haven in February, 1875, when the library of the Sheffield School was large enough to accommo- date the sessions.*

In vietr of the lapse of nearly twenty-eight years between the two New Haven Bteetings, it is interesting to note the important nature of many of the papers pre- sented at the earlier meeting, and the large number of the authors there repre- ented who were present at this meeting, or still survive in active usefulness. For iDsUnoe, Mr. Oloott, now President of the Institute, then presented an im- portant paper on The Ore- Knob Copper-Mine and the Hunt and Douglas Copper Prijcev ; Pr. Kayniond, now Secretary, delivered on that occasion the Presiden- tial Address, 00 the History of the Relative Values of Gold and Silver — a subject deoed to become, politically as well as economically, during the two following deades a '*haming question"; Mr. (now Prof.) H. M. Howe read a paper on

xlviii PROCEEDINGS OF THE NEW HAVEN MEETING.

A Biographical Notice of Clarence King by R. W. Ray- mond (assisted by Messrs. S. F. Emmons, James T. Gardiner and James D. Hague) was then read by Dr. Raymond.

The second session was held Wednesday morning, October 15th, when the following papers were presented in print or in printed abstracts :

Notes on the Treatmentof Zinc-Precipitate Obtained in Cyanid- ing New Zealand Ores, by Hamilton Wingate, Bristol, England*

The Direct Cyaniding of Wet-Crushed Ores in New Zealand, by Hamilton Wingate, Bristol, England.

Coking in Bee-Hive Ovens with Reference to Yield, by Charles Catlett, Staunton, Virginia.

Ore-Deposition and Vein-Enrichment by Ascending Hot Waters, -by Walter Harvey Weed, Washington, D. C.

Ore-Deposits Near Igneous Contacts, by Walter Harvey Weed, Washington, D. C.

The following paper was presented in oral abstract by the Secretary, in the absence of the author :

The Valuation of Mines of Definite Average Income, by H. D. Hoskold, Buenos Aires, S. A.

Prof. J. A. Holmes, St. Louis, Mo., read a paper on Mines and Metallurgy at the St. Louis World's Fair, 1904.

The following papers were read by title for subsequent pub- lication and discussion :

Blaat-Farnace Economy — the first of a long series of contribations to technical literature which reflect credit, not only upon their author, but upon the Institute which constituted from the beginning his appreciative audience ; Mr. W. P. Blake ( now Director of the School of Mines of the University of Arizona) presented a paper on Provisions for the Health and Comfort of Miners ; and George J. Brush, then active and now Emeritus Professor of Mineralogy in the Sheffield School, delivered, in the name of that school, the address of welcome to the Institute. All these gentlemen were present in person at this 83d meeting. Among the papers pre- sented in 1 875 by persons who still remain among us, having fulfilled in useful lives the promise of their youth, the most important, perhaps, was that of Mr. H. S. Drinker on The Musoonetcong Tunnel — out of which paper grew his classic and authoritative imperial octavo on Tunneling. Other important papers were presented by Anton Eilers, Persifor Frazer, E. C. Pechin, Prof. Frederick Prime, Jr., Walter McDermott, and Prof. R. H. Richards. The list of those who con- tributed to the proceedings of the first New Haven meeting, and have since died, includes the names of Prof. Thomas Egleston, Martin Coryell, Peter Ritter von Tunner, Prof. Henry Wurtz, Gen. Henry Pleasants, Prof. Henry Newton, and J. L. Jemegan. R. W. R.

PROCEEDINGS OF THE NEW HAVEN MEETING. xHx

The Lodes of Cripple Creek, by T. A. Eickard, Denver, Colorado.

The Veins of Boulder and Kalgoorlie, by T. A. Rickard, Denver, Colorado.

The Geology of Southwestern Texas, by E. T. Dumble, Hous- ton, Texas.

The Copper-Deposits of Sierra Oscura, New Mexico, by H. W. Turner, San Francisco, Cal.

Amarillium, by Wm. M. Courtis, Detroit, Mich.

The Manganese Industry of the Department of Panama, Republic of Colombia, by E. G. Williams, Colon, S. A.

An "All-Fire" Method for the Assay of Gold and Silver in Blister-Copper, by Walter G. Perkins, Grand Forks, B. C.

Elimination of Arsenic, Antimony and Bismuth from Cop- per, by Allan Gibb, Mount Perry, Queensland, Australia.

The Chemistry of Ore-Deposition, by Walter P. Jenney, Salt Lake City, Utah.

The Geological Features of the Gold-Production of North America, by Waldemar Lindgren, Washington, D. C.

Igneous Rocks and Circulating Waters as Factors in Ore- Deposition, by J. F. Kemp, New York City.

The Ore-Deposits of the San Pedro District, New Mexico, by Morrison B. Yung and Richard 8. McCaftery, San Pedro, New Mexico.

The third session was held on Wednesday evening, October 15th, when the following papers were presented :

The Development of the Modern By-Product Coke-Oven, by Christopher G. Atwater, New York City (illustrated with kntem-slides).

The Blake Stone- and Ore-Breaker : Its Invention, Forms and Modifications, and its Importance in Engineering Indus- tries, by William P. Blake, Tucson, Arizona.*

Prof. Blake, who is a nephew of £U W. Blake, announced at the beginning of this paper the establishment of the '' Blake Stone- Breaker Prize," a more <letailed account of which is given in the following trust-deed :

**K]iow all men by these presents, that I, Henry T. Blake, of the City of 'ev Haven and State of Connecticut, representing the heirs of Eli W. Blake, l*te of 8aid City and State, do hereby transfer, assign and set over to the Board Tnistees of the Sheffield Scientific School certain securities to the amount of iz hoadred dollars in par value, the said donees and their successors to have ttd to hold the said securities and their income and the accumulations and re-

D

t 1 PROCEEDINGS OF THE NEW HAVEN MEETING.

The fourth and concluding session was held on Thursday morning, October 16th.

The following paper was read :

An address on The Geology of the New Haven Region, illus- trated with lantern-slides, was delivered by Prof. H. E. Gregory, of the Sheffield Scientific School.*

Members and Associates Elected. The following persons were elected members or associates by postal ballots of August 12 and September 22, 1902, and have formally accepted their election :

Members.

Mason T. Adams, Linares, Mexico.

Lawrence Addicks, Perth Amboy, N. J.

investments thereof in trust for the following uses and purposes and under the following provisions :

1st. The said Board shall have the charge, custody and control of the prop- erty herein donated for the specific object in view, and shall have power to sell and re-invest said property at their discretion.

Said Board shall use the income of said property from time to time, as said income shall accumulate to a sufficient amount, or so much of said accumu- lated income as shall be necessary, to confer a money prize — said prize to be known as the Blake Stone-Breaker Prize— of not less than fifty dollars in gold coin, on the author of any treatise deemed worthy of such award on some subject connected with Mining or Civil Engineering, and preferably with some branch of those pursuits in which the use of broken stone or ores is a material feature. In the award of said prize, preference shall be given to the work of students, grad- uate or undergraduate, in the Sheffield Scientific School of Yale University.

''3d. Said Board shall appoint from the Governing Board of the Sheffield Scientific School three of its members, professors of engineering, who shall recommend the persons upon whom the said prize shall be conferred.

''4th. Said Board shall establish the regulations and conditions concerning the award of said prize, and shall cause a notice of each award to be published among the Transactions of the American Institute of Mining Engineers or in some other leading Industrial Publication.

"5th. In the diploma awarding said prize, suitable reference shall be made by name to the inventor of the Blake Stone-Breaker, Eli Whitney Blake of New Haven, Connecticut, as a memorial to whom this prize is hereby established.

"New Haven, August 1st, 1902.

"Henry T. Blake.'*

Since the reading of Prof. Blake's paper, the Secretary has received official notice that "The Board of Trustees of the Sheffield Scientific School have made the first award under these regulations, conferring a prize of $50 in gold upon Prof. William P. Blake, for this paper."

This admirable address, intended chiefly as guide and introduction to the inspection, during the afternoon of the same day, of the geological features which it described and explained, will not be published- B. W. R.

PROCBBDINQS OF THE NEW HAVEN MBETINQ. Il

Robert L. Ahles, Oxford, N. J.

H. a Badger, Isaac Harbor, N. S.

Heoiy Acrojd Barker, Hedges, Cal.

Felton Bent, Chester, Pa.

SeTmour K. Bradford, Tonopah, Nevada.

Bobert K Brooke, Birdsboro, Pa.

Arthur H. Brown, Dolores, Canada.

Walter S. Brown, Victor, Colo.

Geoige Tyler Burroughs, Minidora, Idaho.

James M. Clark, Kanawha Falls, W. Va.

Harrison Edward Clement, Bingham Canyon, Utah.

Henry E. Crawford, New York City.

Clarence M. Dickerson, La Colorado Sonora, Mex.

Charles W. Dickson, New York City.

Otto Doeltz, Clausthal, Germany.

Edgar Satchwell Dorman, Missoula, Mont

George H. Dnggan, Sydney, Nova Scotia.

Adolf Ekman, Oroville, Cal.

Augustus B. Emery, Bossland, B. C, Canada.

David L. L. Eynon, Philadelphia, Pa.

Albert Hill Fay New York City.

Robert Forrester, Salt Lake City, Utah.

Floyd J. Foster, Villadama, Mexico.

Charles D. Garfield, Juneau, Alaska.

Joseph L. Giroux, Jerome, Ariz.

Arthur G. Greenameyer, Leetonia, O.

Frank Wood Griffin, San Francisco, Cal.

Maurice Edward Griffin, San Francisco, Cal.

Herbert Haas, Torreon, Mexico.

W. H. Hackett, New York City.

Ernest Ames Haggot, Prescott, Ariz.

Everett J- Hall, New York City.

Thomas M. Hamilton, Helena, Mont.

T. F. Hartman, Boulder, Western A us.

J. L. Hayward, Colombia, So. America.

Arthur H. Jameson, Providence, R. I.

Ellas M. Johnson, Spuyten Duyvil, N. Y.

Owen Johnson Smuggler, Colo.

Ralph IngeraoU Johnson, Denver, Colo.

William A. Kelley Denver, Colo.

Waseley A. KousnetzofT, Yiadivostock, Russia.

Charles Edward Krebe Kanawha Falls, W. Va.

Frank Welton Lehmer, Omaha, Neb.

Henry A. B Leipner, Mt. Morgan, Queensland.

N. E Maccallum, Phoenix ville, Pa.

William Bradford McKinlay, New York City.

Alfred F. Main, £1 Oro, Mexico.

Walter a Morley, Berkeley, Cal.

Charles R Morrison, . Butte, Mont.

Duvid B. Muir, Kennett, Cal.

James J. Murray, Keswick, Cal.

Arthur Charles Nahl, Berkeley, Cal.

lii PROCBEDINQS OF THE NEW HAVEN MEBTINQ.

John B. Naa, Canton, O.

Phil. Budolph de Nenfville, Frankfort, Germany.

George W. Nicolson, Silverton, Colo.

Edmund D. North, Los Angeles, Cal.

Tasker Lowndes Oddie, Tonopah, Nevada.

Ernest V. Orford, De Lamar, Idaho.

Areli C. Overpeck, Rapid City, So. DakoU.

Joseph Sazton Pendleton, Beading, Pa.

John J. Pilgerrin, Eureka, Utah.

Charles Lawrence Poindezter, Tombstone, Arizona.

Charles L. Batliff, San Pedro, New Mexico.

Stuart Lamar Rawlings, San Dimas, Mexico.

Charlei* William Renwick, Isabella, Tenn.

Motaro Sakikawa, Niihama, I70, Japan.

Hex Robert Seeber, Painesdale, Mich.

Frederic John Siebert, Butler, Nevada.

Hoval A. Smith, Bisbee, Ariz.

Howard D. Smith, Berkeley, Cal.

H. fitaehler, Halberstadt, Germany.

Dr. Alfred Stansiield, Montreal, Canada.

William H. Staver, Freeport, III.

James N. Stower, Plattsburg, N. Y.

Seth Russell Swain, El Paso, Tex.

Howard H. Utley, Wilton, Ky.

William E. Wainwright, Broken Hill, N. S. Wales.

Etheredge Walker, Gazelle, Cal.

John L. Wentz, Philadelphia, Pa.

John S. Wentz, Philadelphia, Pa.

Willis R. Whitney, Schenectady, N. Y.

Frederick B. Wilder, Reno, Nev.

David Wilkinson, Johannesburg, So. Africa.

Henry Ide Willey, New York City.

Frederick Tuttle Williams, Victor, Colo.

Associates.

Robert E. Brewer, Cambridge, Mass.

Harold L. Coombs, Globe, Ariz.

Arthur Campbell McCallum, Victoria, B. C, Canada.

Howard Harry Osborn, Mysore, South India.

Charles O. Ripley, Newark, N. J.

Aurelio Sandoval, Nogales, Ariz.

Prospero Sandoval, Nogales, Ariz.

Philip E. Wright, Philadelphia, Pa.

Change from Associate to Member.

Walter R. Crane, Lawrence, Kaus.

Howard R. Stewart, New York City.

William Q. Wright, San Francisco, Cal.

Change from Life-Member to Life-Associate.

Rev. Richard J. Morris, Philadelphia, Pa.

proceedings of the new haven meeting. hil

Excursions and Entertainments.

At all times during the meeting, the buildings, collections, etc., of the Sheffield Scientific School and other departments of Yale University were open to inspection by the visiting mem- bers and guests of the Institute, each of which received also, as a souvenir, a complete illustrated guide to the City and the University, containing much historical, statistical and descrip- tive information of permanent value, as well as immediate use- fulness.

On Wednesday afternoon, October 15th, through the courtesy of the Yale Foot-Ball Association, the visiting members and guests of the Institute enjoyed the spectacle of a foot-ball game between the representatives of Yale University and those of the University of Vermont.

On Thursday afternoon, October 16th, through the courtesy of the Fair Haven and Westville Electric Railway Co., a geo- logical excursion was made to West Rock, where many points of scientific, scenic and historic interest (including, under the last head, the famous " Cave of Regicides ") were inspected.

On Thursday evening, a social reception was given by the Local Committee at the Yale Art School.

Friday was occupied by many of the visiting members and guests in more leisurely examination of the University building and collections — especially the Peabody Museum. Prof. S. L. Penfield pointed out objects of special interest in the mineral- ogical department (comprising the Yale University and Brush collections), and Prof. C. E. Beecher described the exhibition of Dinosaurs and other extinct forms of animal life.

Members and Guests Registered.

The following list (doubtless incomplete) comprises the names actually registered at hotel headquarters, omitting those of about twenty ladies accompanying members :

Lftwreoce Addicks, Perth Amboj, N. Y.

Cbrutopher G. Atwater, New York, N. Y.

Chaa. R Beecher, New Haven, Conn.

F. L. BigeloWf New Haven, Conn.

Theo. Bhike, New Haven, Conn.

WiD. P. Blake, Tucson, Ariz.

W, H. Brewer, New Haven, Conn.

6. J. Bmaby New Haven, Conn.

liv PROCfiEDINGS OF tHB NSW HAVBN MBETING.

Irving C. Bull, New York, N. Y.

R. H. Chittenden, New Haven, Conn.

W. S. de Camp, Fulton Chain, N. Y.

Wm. A. Doble, San Francisco, Cal.

A. J. DuBoifl, New Haven, Conn.

Theo. Dwight, New York, N. Y.

H. W. Farnam, New Haven, Conn.

Albert H. Fay, New York. N. Y.

A. W. Fiero, Chicago, 111.

W. H. Fluker, Tatham, Ga.

Henderson Gilbert, Harrisburg, Pa.

H. E. Gregory, New Haven, Conn.

Thomas Guffey, Pittsburg, Pa.

Alfred £. Hammer, Branford, Conn.

John Hays Hammond, New York, N. Y.

Dana Harmon, San Francisco, Cal.

Frank H. Hartung, Tucson, Ariz.

C. S. Hastings, New Haven, Conn.

C. W. Hayes, , Washington, D. C.

J. A. Holmes, St. Louis, Mo.

Henry M. Howe, New York, N. Y.

W. S. Hungerford, Jersey City, N. J.

Edwin C. Johnston New York, N. Y.

W. J. Johnston, New York, N. Y.

Julian Kennedy, Pittsburg, Pa.

Wm. Kent, " New York, N. Y.

P. S. King, NewYork, N. Y.

I. N. Knapp, Philadelphia, Pa.

Robert G. Leckic, Sudbury, Ont

J. H. Lee, Baltimore, Md.

John Lilly, Lambertville, N. J.

Edwin Ludlow, Las Esperanzas, Mex.

Lesley McCreath, Harrisburg, Pa.

E. E. Olcott, New York, N. Y.

George Ormond, Allentown, Pa.

E. W. Parker, New York, N. Y.

S. L. Penfield, New Haven, Conn.

L. V. Pirsson, . New Haven, Conn.

J. K. Punderford, New Haven, Conn.

R. W. Raymond, Brooklyn, N. Y.

C. B. Richards, New Haven, Conn.

T. A. Rickard, New York, N. Y.

Chas. O. Ripley, Newark, N. J.

J. C. Roberto, . . Niagara Falls, N. Y.

H. B. Sargent, New Haven, Conn.

J. M. Sherrerd, High Bridge, N. J.

Henry Souther, Hartford, Conn.

E. G. Spilsbury, Trenton, N. J.

Thos. W. Stiles, New York, N. Y.

H. H. Stock, Scranton, Pa.

Bradley Stoughton, New York, N. Y.

PROCEEDINGS OF THE NEW HAVEN MEETING. 1v

M. F. Tyler, New Haven, Conn.

Leonard Waldo, New York, N. Y.

W. H. Weed, Washington, D. C.

H. L WelU, New Haven, Conn.

Olaf Wenstrom, Boston, Mass.

Eli Whitney, New Haven, Conn.

£. G. Williams, Colon, Colombia, S. A.

£. H. Williams, Sharon, Pa.

H. S. Williams, New Haven, Conn.

P A P E R S.

Vox* Xxxiii. — 1

The Tombstone, Arizona, Mining District.

BY JOHN A. CHURCH, NEW YORK CITY. (New York and Philadelphia Meeting, Febraary and May, 1902.)

Twenty years ago Tombstone was the most noted mining camp in Arizona. It presented a combination of fissure-veins and bedded deposits in relations which were most puzzling, and impossible to make out until tiie extensive development of the mines permitted every detail of the structure to be observed. These details have been studied with great success by W. F. Staunton, now Manager of the Congress mine, in Arizona, and subsequently by H. J. Gray, and the facta upon which the fol- lowing description is based are mostly the discovery of Mr. Staunton, though confirmed by my own examination.

Tombstone is situated in a country that contains several im- portant mines. On the south, at Bisbee, are the Copper Queen, which Prof. Douglas has described in our Transac- tions* and other valuable mines; on the east the Common- wealth gold-mine and the recently opened copper-mines at Turquoise, or Gleeson, and the older Middlemarch and Black Diamond. Northeast are the Peabody copper-mines. The wolfram discoveries of two years ago were in the Dragoon mountains, towards which Tombstone looks on the north and east

Though the town has no railroad at present, it lies but ten miles from Fairbanks, through which place both the Southern Pacific and the El Paso and Southwestern railways run, and it is expected that in a few months a cut-off on the latter road, between Fairbanks and College Peak, passing through Tomb- stone, will place the camp practically on the main line.

Its general situation is shown in the accompanying map. It lies on the Gadsden Purchase, and is in Cochise county, 25 miles from the Mexican line. The San Pedro river, at Fair- banks and Charleston, afforded an ample supply of water to

♦ Trans,, xxix.,511.

4 The Tombstone, Arizona, Mining District.

the old mills, and the water-supply of the town is drawn from the Huachuca mountains through a pipe-line about 25 miles long.

Considered as a whole, the formation consists of sedimentary beds in contact with an extensive eruptive mass of granodiorite; but with two exceptions (the Lucky Cuss and Knoxville) the best mines are not near the contact, and the eruptive rock does not underlie the productive part of the measures, unless at a depth greater than 3000 feet.

The Lucky Cuss claim has a fissure-vein within 800 or 400 ft. of the granodiorite, and has yielded nearly a million dol- lars; the West Side, another fissure-vein, is 2000 ft. from the contact, and has produced a million and a half; and the prin- cipal fissure of the district, which passes through the Grand Central, Contention and Head Center mines, and has yielded about twelve million dollars, is 4000 ft;, from the eruptive rock. A few of the minor bedded deposits are 600 to 900 ft. from the contact, but their total product did not exceed $900,000 while the principal deposits of this type which have produced more than six million dollars are half a mile distant.

In a district like Tombstone, where surface-deposits of small extent have been opened at a great many points, exception can be taken to almost any statement that can be made, on the ground that ore has been found under conditions that do not agree with the general statement ; but the preponderance which I have expressed in values could be given also in tonnage, if the books of all the mining companies had recorded the output by weight, and it is clearly shown by the comparative extent and permanence of the stopes and veins. It is by the study of the leading mines that the facts of the formation have been ob- tained. They show that the deposition of the ore has an intimate and interesting relation to the structure and dynamical history of the sedimentary rocks.

The observable measures of Tombstone consist of 2850 ft. of sedimentary strata, an intrusive mass of granodiorite and a surface-flow of rhyolite.

The Sedimentary Rooks.

At the bottom of the sedimentary series is the Randolph limestone, numbered I. in Fig. 1, so called from the mine of that name in the Charleston side of the district. A thickness

The Tombstone, Arizona, Mininq District.

Map Of

Tombstone

JohnsonTlUfl FMtodfiUne

MEXICAN BOU N DARY V,- NaCO

6 The Tombstone, Arizona, Mining District.

of 300 ft. is allotted to it, as it is certainly more than 200 ft. thick. It has not been an important producer of ore.

Above it is the Ajax quartzite, EL., a strong anticlinal in this rock forming Ajax hill, the highest elevation in the district, rising 900 ft. above the town. The Mamie and other mines have been producers from this rock, which is 500 flL thick.

Over the quartzite is the Emerald limestone, HL, 420 ft. thick. About the Emerald, the most important mine in it, this stratum consists of thin limestones interleaved with thinner shales. At other localities it is made up of thicker and purer limestones, with thicker beds of quartzite ; but wherever seen it indicates variable conditions of formation. It contains sev- eral mines.

Next in the series is the Lucky Cuss limestone, IV., which has several productive mines besides the prominent one that gives it its name. Its thickness is taken at 400 ft;., but in the southern part of the district it covers a great extent of country, and undoubtedly thickens rapidly, indicating steady and long continued subsidence. It is often fossiliferous, but metamor- phism has made it difficult to obtain satisfactory fossils in any variety. It is full of crinoid fragments and imperfectly exposed corals, the crinoids being most abundant.

Upon this limestone rests the Herschel quartzite, V., which varies in thickness, but in the section given is taken at 270 ft., a minimum. At the surface it has a shaly structure, but in the East Side crosscut is found to be mostly a dense, fine-grained quartzite.

Above it is the first of the more important ore-strata, the White Lime, VI., 60 ft. thick. This rock, which has produced some of the most valuable ore-bodies in the district, has the usual appearance and softness of pure limestones, but in the ore-bodies and their neighborhood becomes very siliceous — so much so that Prof. Kemp, though deciding it to be limestone, found that the specimen sent him resembled a quartzite with lime intrusions. Its character as a limestone is undoubted; and the siliceous intrusion which characterizes it is probably to be ascribed to the solutions which brought in the ore, for it is not present away ft*om the ore-bodies.

Above the white limestone lies the Toughnut quartzite, Vii., 120 to 140 ft. thick. It is one of the three rocks first recog-

Thb Tombstone, Arizona, Mining District. 7

nized in Tombstone as belonging to the most prolific ore- measures. It appears to have shared in the silicification due to sol&taric action ; for, though a quartzite of very fine grain, it gives to one familiar with it the impression of a rock that is not altogether elastic. Prof. Kemp, who examined the rock Oder the microscope, confirmed this impression, as he reported that, in addition to fragments of quartz, it has much cherty

Fig. 1.

Geological Sketch-Map of Tombstone District, Arizona.

silica, and little veins run all through it. The specimen sub- mitted to him was taken in the heart of the mass, and was not near ore. In the mine it appears a massive, tine-grained rock, but not composed of impalpable siliceous paste, like some of the quartzites in the shales.

This rock sometimes contains ore, but not abundantly. There is one small ore-body in it that seems to be connected

8 Thb Tombstone, Aeizona, Mininq District.

with low vertical stopes in a crevice or crevices, and another that shows some limestone, and may have formed in a limited bed of this rock. Another, which unites the Quarry and Girard anticlinal ore-bodies, lies on the Quarry dike, and extends vertically for 40 ft. There are other small irregular stopes near the same dike. Thus, though ore can make in the quartz- ite, special preparation seems to be needed for it. Of occurrences where ore makes in it in contact with an ore-body in limestone it is not necessary to speak. Such exceptions occur in all mines.

Over the quartzite is the third of the original ore-series, the Blue Lime, VIII., 90 ft. thick. Unlike the white limestone, this is a soft, deep-blue rock, a typical limestone ; and it is remark- able, considering the silica imported into the lower members, that this rock haa been unchanged, except in definite lines like veins or in limited areas. In general, the rock is pure.

In the places excepted, there is a dark-blufe silicified fossilifer- ous limestone, evidently an alteration of the parent rock, in which no original characteristic except hardness has been disturbed. The blue limestone has been one of the best ore-carriers in the district, as might be expected from its softness and purity.

Finally, we reach the highest stratum with which we have to deal, known in Tombstone as the shale, IX., to which I will add the name Contention, as that mine has been the principal producer from it. It contains a heavy bed of quartzite, and many thin limestones and thin quartzites ; but the ore-bodies of the fissure-veins go down through all its constituents, and it is sufficient to regard it as a single, though a composite, member. The Grand Central pump-shaft has penetrated it vertically for 681 ft., and is supposed to be still 160 ft. above the blue lime- stone. It forms the surface over most of the productive area, and its thickness there may be taken as 700 ft.

These four rocks — the shale, blue limestone, quartzite and white limestone — will sometimes be spoken of as the Toughnut series, from the mine where these leading members of the Tomb- stone formation were first recognized.

The limestones are non-magnesian, and often fetid, even when bleached nearly white.

Few recognizable fossils were found, though all of the lime- stones are fossiliferous. Fusulina cylindrica was found in the

The Tombstonk, Arizona, Mining Distriot. 9

uartzite above the Lucky Cuss limestone and Spirifer rocky- mmianus in the blue limestone. An undetermined Ghceteies And a Productus were the only other fossils obtained.' The indi- <tions are that the Tombstone beds belong to the higher measures of the Lower Carboniferous, and, perhaps, to the Carboniferous.

The sedimentary rocks are folded into a synclinal about 4000 ft, wide, measured on the center line of the Toughnut claim, with a nearly east and west axis, which pitches from the gran- odiorite eastward. The outcrops lie in an irregular horseshoe which has a deformation near the point of the curve that sug- gests pressure against the granodiorite. They have not been traced beyond a point east of the San Diego mine, but the Lucky Cuss limestone continues there in a line of prominent hills eastward. Except the three Toughnut rocks, this is the only one of the series that can be found near the town — Com- stock hill, a mound 100 ft. high, being composed of it.

The composition of these rocks shows that the geologic his- tory of Tombstone was mostly a very quiet one. There are two or three pebbly limestones, and two or three conglomer- ates with quartz pebbles like walnuts, but nearly all the other rocks are of extremely fine grain. The Ajax quartzite and the thick one included in the shale series are of ordinary visi- ble grain, but the others are mostly of shaly fineness though siliceous in composition. The land mass which furnished the material for these rocks probably lay to the north and west, and sufiiciently distant to send only fine sediments to the local- ity under consideration.

The massive fine-grained quartzites of Tombstone seem to be nearly pure silica, the coarser kinds often containing a large proportion of highly crystalline feldspar, opaque and pink in color. As the quartz grains of the granular quartzites are often perfectly limpid, the combination of these rounded glassy grains with well-developed feldspar makes a product that re- sembles closely one of the dike eruptives. Other quartzites, less frequently found, have much hornblende. These impure rocks resist erosion better than the pure. Sometimes they have a linear direction like dikes, and I suspect these are to be affili- ated with the lines of silicified limestone as a result of the ac- tion of hot water or hot gases.

10 The Tombstonb) Arizona, Mining District.

Elevation succeeded the formation of the rocks, and the steep dips in places where it can hardly be attributed to subsequent history indicate that this movement was not insignificant.

The Eruptive Rocks.

The next step in the process of preparing Tombstone for its mineral wealth was the intrusion of an extensive mass of gran- odiorite. It has a maximum width of about 10,000 ft., and a length of 16,000 from its contacts on the south to the line where it disappears towards the north, under the gravel of the 12- mile-wide valley which separates Tombstone from the Dragoon mountains. It may have some relation to the granitic rock which forms the front of Cochise's stronghold in those moun- tains, and reaches several miles out in the floor of the valley.

This mass intruded somewhere below the lowest of the known measures, and faulted the rocks at the southern contact, lifting a block from which the sedimentary rocks have been mostly removed by erosion ; but patches of them, and in one case a considerable hill, are found scattered over its surface. These patches are mostly limestone which contained a decided propor- tion of silt, if we may judge from the products of contact-meta- morphism. Sometimes quartzite is found, and the composition of these remnants recalls the Randolph and Emerald limestones.

It is evident that the eruptive rock has suffered but little erosion except towards the valley. N'ear the southern contact it is possible often to walk on the original surface. This fact permits the minimum thickness to be calculated, for the upper surface is now on a level with the Herschel quartzite, and the granodiorite has risen 1600 to 1800 ft. above the level of its en- trance, even if it intruded directly under the Randolph limestone.

The eastern face of this mass, on which the ore measures abut, is, so far as it can be observed, a sheer fault. At the Lucky Cuss a crosscut on the 140-ft. level reaches the grano- diorite at a point vertically under the contact, and on the 340- ft. level a crosscut directly underneath failed to reach the erup- tive rock, though pushed nearly to the same distance. The mine is nearly 700 ft. deep, but the dip of the vein takes the openings at the bottom about 600 ft. away from the granodi- orite.

Northward from the Lucky Cuss the surface is covered by

Thb Tombstone, Arizona, Mining District.

gravel, and the eruptive rock is exposed only in gulches on its eastern aide ; bat the conditions indicate that the whole of this side, for a distance of nearly a mile, is a faultrface, and the presence of this vertical face of rigid rock has been one of the factors in Tombstone's history. The western side is also a &alt, and abuts on the Ajax quartzite, the width of the block being about 4000 ft, opposite the mines.

The surface-distribution of the rocks in the Tombstone barin is shown in Fig. 1. Fig. 2 is a section taken in a NE.- SW. line through, and nearly parallel to, the Grand Central mine, on a line north of the area where the extreme thickening of the Lucky Cuss limestone begins. The ore-bodies of the

Fig. 2.

Oaano Central

NE.-SW. Section on Line Shown in Fig. 1, through Grand Central.

Grand Central are indicated in longitudinal section, to show their position in the so-called shales.

Fig. 3 shows the ore-measures from the outcrop at the town to the Contention mine, being a section taken at right angles to that in Fig. 2. The position of the dikes is indicated, and two of the ore-bodies of the Contention in cross-section. This is the region of the bedded deposits in limestone where the struc- ture is exhibited by extensive mine-openings, and the section is confined to the rocks that outcrop here.

The last addition to the surface-rocks of the district was a flow of rhyolite, which covers an extensive field lying entirely on the Charleston side of the divide which separates that de-

The Tombstone, Arizona, Mining District.

fuiict town from Tombstone. Not even fragments of it can be found on the surface of the latter's territory. It rests on the Ajax quartzite, at least on its eastern side, and reaches from Ajax hill, which will be fouod on the map, northwest beyond Fairbanks and southwest to the hills on the San Pedro river, through which the Huachuca pipe-line passes.

Great numbers of dikes are found in the granodiorite, in the sedimentary rocks and in the rhyolite. In the first-named eruptive rock they run in all directions, and are remarkable only for their occasional small size. One of granophyre was

Fig. 3.

. Intcrvcnor Wet Sim I

Cohtemtion

NW.-SE. Section on Line Shown in Fig. 1.

4 in. thick and 60 ft. long. The sedimentaries are especially rich in dikes at their contact with the granodiorite.

In that part of the sedimentary rocks where the ore-deposita Are found the dikes are very regular in strike, parallel, and probably a mile and a half long, and they owe this regularity, probably, to the influence of the fault-face of the granodiorite. The fault runs nearly N., the dikes K 23° E., dipping W. 80°. Against this fault-face, also, folds of the strata have been devel- oped, whatever beginnings they had before, and the dips are teeper near it than elsewhere.

In the area traversed by the five dikes of the mines there are

Thb Tombstone, Arizona, Mining District. Is

none in other directioiis ; but in the Lucky Cuss limestone and eastern part of th.e basin there are quartz-felsite dikes 150 ft. thick, striking N. 70 E.

The materials of the very thin dikes are always granophyre usually a pink variety, with well-marked granitic texture, and these are abundant in the granodiorite, as also are dikes, usually mneh thicker, of a dark granophyre with large feldspars. It is- the latter variety -which is found exclusively in the dikes of the ore-ground, except one diabase dike in the Northwest and Vi- nn& mines. Several diorite dikes are found in limestone near the contact, and though several feet in thickness, they are often very short. It may be that there is an uneroded portion in the limestone. They are probably a portion of the great eruptive mass in dike form, and have not been found at any great dis- tance from it.

The two varieties of granophyre are not infrequently asso- ciated in one dike. The distinction made between them here id due to the absence of the pink variety from the ore-meas- ures. An interesting occurrence of minette in granodiorite near its contact with Lucky Cuss limestone is referred to in connec- tion with the mine of that name. In the rhyolite, dikes of quartz-augite-porphyrite and mica-hornblende-porphyrite were noticed. Erosion, of course, has been strong, for whatever mass WBB lifted up by the granodiorite has been removed almost completely ; and this has been done since the rhyolite eruption, for the summits of that rock now stand 1000 ft. above the granodiorite and within half a mile of it. That flow would certainly have poured into the Tombstone basin, and left its traces there, if it had not been restrained by some lofty barrier.

It is to be hoped the United States Geological Survey will turn its attention to this interesting field, which is too exten- sive to be studied by private enterprise alone. The formations of the Whetstone, Dragoon and other mountains that en- circle Tombstone stand in evident relations with each other and with the developments of eruptive rocks, which form a more extensive series than I have indicated. If properly studied, this would probably be found to be one of the simpler types of structure in Arizona.

14 the tombstone, arizona, mining district.

Position op the Ore.

There is nothing in Tombstone that indicates the original seat of the metals which formed the ore ; but the structural conditions point strongly to some underlying source from which they have risen, through fissures, to be deposited in the fissures and in strata which had been prepared by folding for the entrance of solutions. The granodiorite has not acted except by its inertness, and the role of the dikes has been almost equally inferior. The rocks owe their ores almost entirely to the two results of pressure — folding and fissuring.

The folding is in two directions, producing anticlinals, with axes varying in direction from S. 15° E. to S. 65° E. from their outcrops, and monoclinal flexures which lie across the anticli- nals. They are usually of gentle slope while the anticlinals are often highly compressed, and, in two or three instances, faulted. The level parts of the monoclinals sometimes rise a little, instead of descending ; but the rise is too unimportant to destroy the contrast between the folds in the two directions.

The bedded deposits lie in the anticlinals, sometimes on the flank, sometimes in the apex; but the synclinals are barren. The monoclines do not seem to have limited the deposition of ore, which is found both where they dip strongly and where they are nearly horizontal. The com- pound surface produced on any stratum by these cross-folds, with their varying direction of axes and steepness of dip, is of unending variety, and undoubtedly has been a controlling factor in the distribution of ore, which is found in all shapes, from long, narrow tongues to broad sheets. There is nothing like the superposed saddle formation, made familiar to us by Rickard and others. In the Goodenough incline, especially, there are as many as three sheets of ore at different levels in the blue limestone, and they coincide vertically for portions of their extent ; but they differ in the direction of their axes and dips. The simple anticlinal structure of the saddles is dis- turbed by the monoclinals.

Fig. 4 shows the anticlinal folding along the line of the West Side vein and across the Toughnut and Goodenough claims where the flat ore-bodies have been most important. It will be seen that there are two principal anticlinals, one in the West Side and one at the Quarry in the Toughnut. On the

Thb Tombstone, Arizona, Mining District.

O Id

Si

(I)

o

o P

16 The Tombstone, Arizona, Mining District.

flanks of these are subordinate folds, which constitute the other anticlinals shown in Fig. 6.

One of the monoclinal flexures across these anticlinals has been plotted in Fig. 5, showing the irregular stopes in the Northwest mine of the Toughnut claim, which have received the name of Hoodoo. On this line there are great numbers of small, vertical crevices, which have sometimes received enough ore to join two overlying bodies together. In the section of this figure the ore-body B occupies the flank of an anticlinal which dips towards the spectator. A and all the others are seen in true section.

Compression-Fissures.

Two lines of vertical fissures are found lying across this system of anticlinals. On one, which has a strike of N. 15° E., the Grand Central, Contention, Head Center and Tranquillity mines are opened, while the other, striking N. 42° E., con- tains only the West Side mine. Their positions with relation to the anticlinal deposits are shown in Fig. 11.

The anticlinals are persistent from their outcrops on the Vizina, Goodenough and Toughnut claims, near the town, to the Contention and Grand Central, and in the fissure-veins we find the distinctive peculiarity of Tombstone, which binds the bedded deposits and fissures in one system. The largest ore- bodies of the fissures are found within the lines of these anti- clinals, whether the fissure has been deep enough (as in the West Side mine) to reach the blue and white limes, which are the rocks that contain the bed deposits, or are still in the overly- ing shale (as in the Contention and Grand Central). The water- level in the last-named two mines is calculated to be 160 ft. above the blue limestone, which contains the highest ore- bodies of the Toughnut series ; but the influence of the anti- clinals upon the deposition of ore in the fissures is as marked in the overlying shales through which the fissures pass in their upper levels as in the limestones of the bedded deposits.

The second result of dynamic action was the production of these vertical veins, which I regard as compression-fissures. They have been studied most thoroughly in the West Side mine, where the principal ore-body of the fissure was confined to a strongly compressed anticlinal about 450 ft. long. This

The Tombstone, Arizona, Mining District.

fold is succeeded on the north by a broad and barren synclinal and on the south by a narrow synclinal and a gently rising anticlinal. The fissure passes through shale for the first 200 ft. of its depth, and there is a small ore-body within the syncli- nal in the shale. It does not extend into the blue limestone below, and is probably due to secondary deposition.

There are at least three known paraDel fissures within a width of 400 ft. at the West Side, two of which have yielded ore, though the West Side is the only important producer. The walls do not indicate faulting; and though a cross-fault of small throw is observable, it is probably a dislocation of slabs rather than of a section of the country.

Fio. 6.

Showing Monoclinal

Hoodoo Stores

Northwest Mine

Flan and Section of Monodinal Flexnre.

In Fig. 4 the ore-bodies shown in the West Side mine are all in the fissure, the anticlinal deposits stretching away from the vein on the side opposite the spectator. The ore-bodies of the Goodenough and Toughnut, on the other hand, are exclusively anticlinal. In order to show the grouping of the ore-bodies on the anticlinal, it was necessary, in a drawing on this scale, to project the flat bodies on their entire dip. The figure is faulty, flierefore, in showing the ores of the fissure in section and the ores of the anticlinal in projection. Still, the figure exhibits the anticlinal deposition both in the beds and fissures, and the synclinal barrenness. Of the two ore-bodies in the West Side, VOL. . — 2

18 The Tombstone, Arizona, Mining District.

the one Jying in the sharp anticlinal is markedly superior, both in size and grade of ore. The inferior one occupies the fissure where it passes through strata of gentle dip, and here there is no deposition along the anticlinal axis, as there is in the sharp fold.

Although the Contention and Grand Central mines are not yet sufficiently cleaned up from the effects of the fires which closed them to permit examination, the extent of their ore- bodies is shown in a report made about 1890, by the late H. G. Howe, who was for many years the leading surveyor at Tomb- stone. He gives sections of the ore-bodies, reproduced in Fig. 8, which are taken from the south end of the Grand Central to about the center of the Contention. They show very clearly the combination of inclined' anticlinal deposits and a vertical vein; and the relation of the two is more striking here than elsewhere in the district, because the two classes of deposits dip in opposite directions — the vertical to the west, the anticlinal to the east

What is called commonly the Contention vein is a series of nearly vertical ore-bodies which extend northerly through the Grand Central, Contention, Head Center, Tranquillity and Sil- ver Thread claims, a distance of nearly a mile. There was no one continuous vein along this line, but a series of large indi- vidual ore-bodies lenticular in cross-section, dipping to the west (with the dike) and pitching to the north. Thus, it is not to be supposed that the upper ore-body in Sec. 3, Fig. 8, has given out abruptly in full width. The figure shows a vertical section through an inclined mass, but the latter did not reach to the. next section 320 ft. north.

There were several of these bonanzas in the 400 feet of shales that separate the Contention and Empire dikes, and in the shale east of Contention dike. Mr. Howe says the Grand Central had four " of these chimneys of ore," the Contention three, Head Center one and Tranquillity two. The largest of these is figured in Sec. 4, Fig. 8. Mr. Howe says it outcropped on the surface and extended to the 600-ft. level, pitching to the north ; but the section shows that it was formed by three fissures in echelon. On the 300-ft. level it was more than 400 ft. long, and had a max- imum width of 80 ft. A hundred feet lower it was 200 by 40 ft. These are large dimensions for so rich an ore. The sections

The Tombstone, Arizona, Mining District.

show that the ore-bodies lay in echelon, several of them appearing in some of the cross-sections, only one in others. It is probable that the parallel crevicing found in the West Side mine is pres- ent here also. Three sections show anticlinal deposits. Of that in Sec. 2, Fig. 8, Mr. Howe says : " This ore-body was discovered on the 800-ft. level, and followed up by a raise for 50 ft., where a large body of ore was discovered which lay almost flat; and development also showed that it pitched to the east, and a winze was sunk for 60 or 70 ft., following down upon its dip; but no drift was run along this ore-body at the bottom of the winze, and its extent is not known." No effort was made

Fio. 6.

Subordinate Anticlinalfl, etc, as Belated to Ore-Bodies.

to croflsnt to this ore from lower levels. The three sections showing anticlinal ore-bodies are not successive sections, being separated by two others, in which only vertical bodies are shown. The meaning of this cannot be determined from the old maps, and partly for the reason that the anticlinal ores were not mined or even drift;ed upon, except one below the water-level, though the grade was good. The " East bodies " shown by Mr. Howe are opposite the anticlinals mined in the Toughnut series further north. The largest of the anticlinals ha been followed on ore for 1150 ft. from the West Side vein, or aboot half the distance to the Contention. The disposition of ore-bodies along anticlinals was not generally known when

20 The Tombstone, Arizona, Mining District.

Mr. Howe made his sections, and it is probable that the Grand Central and Contention system consisted of nearly vertical ore- bodies along or near the dikes, and of others, more gently in- clined, in anticlines crossing from one dike to another and be- yond. The west dip of the vertical shoots and the east dip of the flatter deposits is strong evidence of this. The vertical ore- bodies were found in the center of the ground, between the dikes as well as under them.

This series of ore-bodies was the most productive of the Tombstone mines, and the explorations in depth are anticipated with great interest. When the great ore-formations of the dis- trict, the blue and white limestones, are reached by the 'Con- tention-Grand Central vein in the next 200 to 300 fk., it is expected that the conditions of maximum dynamic effect will coincide with the presence of the most favorable ore-rocks the district has had.

These compression-fissures are one of the most important features of the formation, and have probably been the most prominent factor in the introduction of ore, as the anticlinals have been in its distribution.

Until the Contention and Grand Central are opened suffi- ciently to allow of careful inspection, it will not be possible to say whether their ore-bodies occupy similar fissures ; but the occurrence of ore in the middle ground between the Contention and Empire dikes, which are about 400 ft. apart, leads to the supposition that compression-fissures will be found there. The Head Center fault which cuts the Contention vein and dike is parallel to the West Side fissure.

Nowhere in the district is ore found in the shale except in the fissures, but its presence there proves that this rock was not unfitted for the reception of ore, by whatever method it was formed. The mobility of shale under pressure is supposed to prevent the maintenance even of minute openings, and the general absence of ore from this formation is new evidence of the controlling necessity of crevices as a preparation for ore. In Tombstone there is a contrast between the behavior under pressure of bed-seams and vertical crevices in the shale that is worthy of note. The weight of the rocks, which may not have been more than 500 or 600 ft. thick, was suflicient to close the bed-seams, but not to crush the vertical fissures, and the

Thb Tombstonb, Arizona, Miking District. 21

delicacy of this difference is shown by the fact that a limestone 2 ft thick has been mineralized for hundreds of feet on its dip, while the shale in which it is inclosed is barren. If such a stratom is what Mr. Bailey Willis calls " competent " enough to protect and keep open a bed-seam, the pressure of the over- lying rock must have been small.

There is another kind of firacture which is found very abun- ilantly in the blue and white limestones, and to some extent in die Toughnut quartzite, but not in the shale. Cracks of this class occurring in limestone often end abruptly at the contact with quartzite, and I suspect that is the rule, and that these crevices have been produced by a force that affected each rtratam of rock for itself, without necessarily producing the same effects in other strata.

Torsion-Cracks.

The most important of these cracks is the Defence vein, which strikes N. 57® E. It is in outcropping blue limestone, and does not enter the underlying quartzite. Another is the Way Up crack, which has most of its length in the Good- enough. Its strike is about N. 65° E. Near it are two minor vertical stopes in the Qoodenough incline, one striking E. and the other 8. 88® E. On the 200-ft. level of the same mine there is one with strike N. 67° E., which has yielded more ore than any other except the Defence. None of these penetrate the shale, and tiie few stopes in quartzite nearly on the line of the Way Up crack are close to the Quarry dike, and probably due to its influence. There are some small vertical stopes in the quartzite on the Toughnut claim where the Hoodoo stope enters it; but here, as elsewhere in the quartzite, these crevices are few and insignificant, in comparison to those in the limestones.

The restriction of these crevices to the limestones and quartzite points to an origin diflFerent from that of the cora- pression-fisBiires which penetrate rocks of all kinds and have vertical continuity. I am inclined to ascribe these inferior cracks to the results of torsion accompanying the deformation of the strata by pressure at an acute angle against the grano- diorite,the results being produced in each stratum independently of the others. Being Confined to the firm rocks, it might be €ipected that the brittle quartzite would show them most

22 The Tombstone, Arizona, Mining District.

prominently, which is contrary to the actual conditions; but the quartzite occasionally shows crushed areas where the rock has been broken to a mass of breccia, entirely non-coherent, for several feet in thickness, and these may show how this rock adjusted itself to a strain which made crevices merely in the limestones.

The crevices are most abundant in the area of Fig. 7, and especially toward the Defence vein, which is just outside the figure, below the lower left-hand corner. Fig. 7 is but a poor representation of the number and diversity of strike of those at the northern end of the Hoodoo stopes lying in that quarter. Probably not half of them were noted. Many are barren cracks ; others make small vertical stopes confined to one or more layers in the limestone. The crevices here are not long, continuous cracks, though some run for a few hundred feet ; and it is noteworthy that these are not the best carriers of ore, probably for the reason that their length and direction take them out of the narrow limits of anticlinal deposition.

Though the Defence vein is in blue limestone exclusively, the crevices shown in the same line in Fig. 7 are in the lower white limestone, the upper stratum being entirely eroded at this point, and they depart strongly from the strike of the Defence, the line curving until it is nearly east and west. Ore has been mined from the outcrop of the overlying quartz- ite, but it is obviously of secondary origin, and has no contin- uance in depth.

These cracks are found throughout the area of Fig. 7, but they are more abundant near the line of the Defence vein, which is in the area of greatest deformation, and on the line of the West Side fissure, which is 500 ft. or more below the right-hand half of the figure. There is no fissure passing through these places, no continuity in the cracks, parallelism or other connection between them. The whole Defence system belongs to what I will style these torsional crevices, and they are also strongly developed in the line of greatest com- pression in that neighborhood, the line of the West Side

fissure.

Relation of the Dikes to Orb.

The third factor in the forces which* have made the Tomb- stone formation is the series of dikes, the filling of which has

Thb Tombstonb, Arizona, Mining District.

been determined as granophyre and diabase. Nearly all the ore derived from it has been taken from the 2500 ft. of ground ly- ing between the Northwest dike on the west and the Contention dike on the east ; but the deposition of ore is not confined to the space included between these two dikes. It has been mined in the Defence 500 feet and in the IngersoU 1000 feet west of the Northwest dike, and in the Tranquillity some distance east

of the Contention dike.

Fjo. 7.

Plan and Section of Torsion-Cracks, Northwest Mine.

Fig. 3 shows that one of the principal vertical ore-bodies of the Contention and Grand Central is east of that dike. At least one of the anticlinal ore-bodies in these mines has the same position.

These facts show that the dikes did not have a limiting effect upon the passage of ore solutions. Locally they have modi- fied deposition, but in general their presence was so inert that we must look elsewhere for the controlling factor, and that, as already said, is probably the two results of pressure — folding and

24 The Tombstone, Arizona, Mining District.

fissuring. All these elements of the problem, except the fis- sures, are combined in Fig. 6, which shows the ore-bodies (in outline) of the blue and white limestones, the axes of the anti- clinals, the directions of some of the crevices, and the positions of the dikes. It shows that along the Quarry dike there is ore connecting the deposits of the Quarry and Girard anticlinals, and that on the Hawkeye dike there is some spreading of the ore in No. 6 anticlinal. The Combination and other ore-bodies begin at the Northwest dike ; one small deep-lying ore-body in white limestone ends at the Hawkeye dike. These occurrences are, however, very inferior in importance to the deposition along the crevices and anticlinals.

This figure covers the territory of the Toughnut and Q-ood- enough mines, with a portion of the Hawkeye and Empire. The names given to the different elements of the figure re- fer, of course, to mines and particular openings in mines. The Northwest and Quarry are both on the Toughnut. Combina- tion, No. 6, Goodenough and Way Up are all on the Good- enough. The crevices are named from the places of their prin- cipal development. Each class of occurrences exhibits more or less parallelism in its members, but there is no parallelism between different classes.

In no case that I have found has a dike been a seat of orig- inal ore-deposition. The ore-body in the Toughnut quartz- ite along the Quarry dike is in the slabbed ground by its side, though the dike is thoroughly decomposed. The dikes have been drifted on and cross-cut in the anticlinals, and in all other situations, and the trivial amount of ore they have yielded must be attributed in part to secondary deposition, aided, perhaps, by the quickly diminishing influence of some crevice. In the Con- tention and Grand Central, where it is probable the deposition of ore has been determined by strong fissuring, the dikes may have been more affected than elsewhere ; but all that is known about those mines indicates that their ore-bodies lay near, but not in, dikes.

On the surface the dikes often retain their original character unchanged, and their outcrops can be distinguished at a glance. Underground they are completely decomposed, and it is often impossible to distinguish between the rocks derived from them and from the quartzite. On the other hand, in the fissures it

26 The Tombstone, Arizona, Miking District.

is common to find an ordinary appearing quartzite where there- should be none of that rock, and with curious frequency the- phenomenon is found on one side of the vein and not on the other, though in a few feet more the crossing of a stratum dis- proves the possibility of faulting. Apparently the vein, before its decomposition, acted as a dam, on one side of which silici- fication took place, while the other side was free from it.

It is odd that the conditions of dike-decomposition men- tioned are not found outside of the especial ore area. The Comet mine has passed through decomposed to unchanged dike- in 400 fib. In the granodiorite many of the dikes have suffered so much surface decomposition that they are now oxides of iron, calcite, etc., in a feldspathic magma. They resemble altered limestone, but in a few feet their original texture returns, re- versing the conditions found in the Toughnut and Contention*

Ore-Deposition in Limestone.

It is evident that the Tombstone ores are the product of re- placement, both in the crevices and the anticlinals. In the latter, especially, alteration-products, of the sort usually found in limestones, are common and are often rich in metals. The capriciousness of the attack of the ore-bearing waters upon the- limestone is sometimes extraordinary, especially in the region? of torsional fracturing. An example is shown in Fig. 9, Sees* 1 to 15, made from careful measurements of the 50- to 150-ft ore-body in the Northwest mine on the Toughnut claim, where- torsional cracking is especially strong. This body, or series- of ore-bodies, extends almost from the surface to near the 150- ft level, and the sections, taken from A to B, on Fig. 6, cover a length of 250 ft. The ore is entirely in the white limestone with the overlying quartzite showing in a surface cut in Secs 13, 14 and 15. The ore-bodies that lie in one vertical plane- are enclosed in a panel numbered for each section.

The ore began near the shaft in a vertical fissure which i& marked A throughout the series of sections. In Sec. 2 three flat ore-bodies, marked B, C and D, came in below the vertical, and Sec. 3 shows that one of these joins the vertical, which drops- down about 40 ft. in a horizontal distance of 15 ft., while the other two stopes have coalesced.

In Sec. 4 the vertical stope has disappeared, and A marks- the position of a drift along the crack. Now all three of the:

Thb Tombstone, Arizona, Mining District. 2T

flat stopes have run together, and form an inclined body with a steep dip, but not vertical. In Sec. 5 the vertical comes in again, joining the highest of the three flat stopes in Sec. 2, and in Sec. 6, only 6 ft. distant, the vertical stope has gained no less that 40 ft. in height Meanwhile the two lower ore-bodies, C and D of Sec. 2, have disappeared, and do not appear again until we reach Sec. 9 ; but in Sec. 6 a new ore-body, E, comes in,, which continues through seven sections. Only one of the flat ore-bodies has marked persistence. B of Sec. 2 continues through a variety of changes to Sec. 14, and it is notable that the whole series begins and ends with the vertical stope A standing alone, though it has frequently disappeared entirely in intermediate sections, and in Sec. 15 looks like a flat stope. In Sec. 10 a new ore-body, F, comes in, which is the beginning of the Hoodoo ore-body along the Quarry anticlinal, Figs. & and 6.

A study of these sections shows that there is nothing like a vertical vein in this place. There is verticality in certain stopes along one line for a short distance ; but as an ore-body it is ftJly as irregular as the most variable of the flat stopes, and it is less persistent than one of the latter. It is entirely probable that the vertical arrangement which the flat stopes assume when they coalesce is due to the existence of other cracks in their path. The deposition of ore may have changed from one crack to another, limiting itself to a certain width, within which lie the flat stopes which show by their dip that their ehape and position have been determined by the anticlinal folds.

This is well shown in Fig. 5, which is a plan and section of the Hoodoo stope, in the same Northwest mine. Its beginning is the stope F of Sees. 10 and 11, Fig. 9. The position of Sec. 10 is shown on Fig. 5 at F. The strike of these two series of ore-bodies is nearly at right angles. On the lower edge of the plan. Fig. 5, beginning at F, narrow stopes will be noticed following one general horizontal direction. This is the line of the Hoodoo crack, which is ore-bearing only at isolated points. Whether it is one continuous crevice or a series of nearly par- allel cracks crossed or touched in slight echelon by the flat stopes cannot be determined. The general conditions of the creviced area incline me to believe that the ore is not always in the same crack. As in Fig. 9, the vertical deposition of ore

28 Thb Tombstone, Abizona, Mining District.

18 very limited. Besides the Hoodoo crack, there are several others at various angles that show vertical deposition for small heights.

The silicified fossiliferous blue limestone already mentioned is another product of this fissuring, and also of replacement. It is found on the surface and underground in lines of limited length, appearing like veins, and in the mines areas 100 ft. wide have been passed through. They consist of this silicified rock, with scores of open crevices several inches wide. If othing like this is known in the white limestone. This replacement was not accompanied by metalliferous deposition, except to a feeble extent. Assays of 1 to 8 ounces of silver are sometimes had from the rock, but not always. There is no recognizable relation of this rock to the ore-bodies. It is found both near to and distant from them, and is, perhaps, the only rock in the district that shows no sign of yielding to the influence of sec- ondary deposition. This may be due to the filling of the pores in the original rock by silica before the replacement began.

Some of the thin limestones lying in the shale have been ore-carriers in the vertical veins and anticlines, and the richly mineralized layer which was called the East body of the Con- tention was probably one of these shale limestones.

Manganese of the Luckt Cuss Mine.

Of the mines in the lower measures, the Lucky Cuss, Fig. 10, is the most interesting. It lies within 400 ft of the grano- diorite, and outcrops about 350 ft from a dike which Prof. A. A, Julien determined to be a minette, and which lies in the granodiorite close to the contact with limestone. A mass of this rock, 16 ft. thick, encountered below the 850-ft. level, is attributable to an apophyse from the dike. A section from it showed some chlorite, which seems to be absent from the dike. Similar occurrences are found in the Combination ore-body and elsewhere, but none so far from a dike as this.

The Lucky Cuss has had two principal ore-bodies, connected by a cross-shoot at about the fourth level, and several pipes of manganese ore, of which only one is shown in Fig. 10. Most of them are of limited depth ; but this one, though otherwise of small dimensions, had a vertical depth of 350 ft.

The origin of the manganese in this mine, and also in the Knoxville and others, is a question of great interest, and was

Thb Tombstone, Arizona, Mining District.

discussed by C. W. Goodale in a paper before the Institute.* The subject received enlightenment when, under the tongue of minette on the 350-ft. level of the Lucky Cuss, a mass of rock was found which was rich in alabandite, or manganese fiulphide, mingled with galena and pyrite. In this position, protected by the dike-rock from the infiltration of surface- waters, the original form of the manganese seems to have been preserved. It is difficult to believe, however, that all the man- ganese-oxide deposits, which usually form pipes disposed in an erratic manner over the surface of the limestone, represent old deposits of alabandite in place. I am disposed to regard some or all of them as secondary depositions derived from masses or impregnations of the sulphide in the limestone, and prob-

Fio. 10.

Section Of Ore Bodies

Lucky Cuss Mine

SCALE : l"= 400'

bly, in part, from its eroded portion. There is some manga- nese-oxide in all or most of the Tombstone mines, but the quantity is small in the strata above the LuckyjCuss limestone. This and the Emeraldjijmestojie produce basic ores wherever opened; bat, as Mr. Goodale has pointed out, the true mapgar ne86K)re8 are confined to two localities. The first comprises a series of mines, the Knoxville, Wedge, Lucksure and Lucky , lying very near the contact of the granodiorite. The second group, containing the Emerald, Bunker Hill, Rattle- snake and Mammoth, is about a mile S. of E. from the contact, and the C!omet is still farther away. This group yields basic ore, bnt the proportion of iron and lime is greater, and of manga-

IVans., xviL, 767, and zviiL, 910, with section of ore-bodies.

The Tombstone, Arizona, Mining District.

nese much less, than in the mines near the granodiorite. In both groups the manganese seems to decrease with depth.

The most extensive deposits of manganese are those of the Lucky Cuss and Knoxville. The Lucky Cuss has a fissure with chamber deposits of small extent reaching from it into the limestone walls. The Knoxville is described by Mr. Q-ood- Ale as a series of four ore-shoots lying in the line of a contin- uous closed crack. The relation of these two mines to the anodiorite is shown in Fig. 11.

The distinctive manganese deposits are the only ones in the

Fig. 11.

Plan, Showing Relation of the Contention and West Side Fissares to the Anticlinal Deposits, and of the Lack Cuss and KnoxviUe Mines to the Granodiorite.

district that indicate by their position an intimate connection with the granodiorite. The mines in the Randolph limestone, which also yield a basic and somewhat manganiferous ore, are :about 3000 ft. from the contaet. The presence of alabandite under an apophyse which is derived from a dike in the grano- diorite, and the occurrence of the Comet ore under a grano- phyre dike, are indications that the entrance of manganese did not follow immediately upon the intrusion of granodiorite. It must therefore be ascribed to aqueous deposition. There is strong evidence that the bodies of oxide are depositions from .solutions, but it cannot be determined whether they always oc-

The Tombstone, Abizona, Mining District. 31

<!npy the position of original sulphide bodies, which they have enlarged, or have sometimes entered barren cracks and replaced the limestone walls. The Lucky Cuss ore, which was so rich at the sur&ce that slags made from it contained 43 per cent. MnO, gradually lost manganese and gained silica and lead. This vein undoubtedly received large accessions of oxide as a condary deposition. Something of the same kind seems to have taken place in the Knoxville, where, Mr. Goodale says, the ore-pipes had a siliceous center, surrounded by a richly manganiferous shell next the limestone.

All the manganese-ores were very poor in gold at the sur- fiwe, and I believe the Knoxville did not chauge ; but the Lucky Cuas improved so much that the ore below the water-level con- tained $12 per ton of this metal. The alabandite of the Lucky Cuss was not a solid mass of that mineral, but a local enrichment of the sulphides of manganese, lead and iron, the greater portion of the mass being silica and limestone, though there were masses of the manganese sulphide several hundred poands in weight.

The Comet mine, the largest of the manganese deposits, is an instance of the wide extent of ore-deposition in the district, lying 2200 ft. east of the Grand Central. Active deposition has taken place over an area in the Tombstone basin about 10,000 ft. long from north to south and 7500 fti from east to vest. This does not include tlie mines on the Charleston slope.

The Comet vein lies under and in contact with a granophyre dike 60 ft. thick, and has been mined for a length of 2000 ft., and to the 400-ft level. Its ore is valuable for its fluxing qual- ity, besides the silver.

Mines in thb Rhyolite.

A mine of great interest from its position in the rhyolite is the State of Maine. The rhyolite on the side nearest Tomb- ne is poured out on the Ajax quartzite. In the State of Maine there are two nearly parallel veins in the rhyolite which reach down to the underlying quartzite, 375 ft. deep on the in- cUnation of the shaft and 240 ft. vertically. The quartzite has been cracked by the heat to a shaly condition, or at this point one of those changes of composition which are frequent and sodden in this district may have occurred.

The sedimentary rocks are folded, and at one point appear

82 Thk Tombstone, Arizona, Mining District.

to be broken. It is possible that the rhyolite takes the form of a dike there, about 60 ft. thick, but the question cannot be de- termined until greater depth is reached or the rhyolite is cross- cut. The veins are from 2 to 7 ft. thick, and quite irregular in strike, so that they come to a junction with an angle between them of 20°. AVTien parallel they are about 50 ft. apart, and both dip ITW, 45°. These interesting veins have been very profitable for the amount of metal they have yielded, which was probably $600,000. The mine is not now in condition for proper examination, but the stopes resemble strongly those in limestone. The hanging is a smooth continuous wall of rhyo- lite, the veins very soft and decomposed, and apparently they carried ore in individual ore-bodies rather than a continuous vein. Their average strike is N. 35° E., and dip of the incline 40° K 55° W. The dip varies from about 88° to 48°, with much larger variations for short distances. The ore was man- ganiferous and rich in silver.

There are many other openings in the rhyolite, and the min- eralization of this rock appears to have been quite extensive, though the number of profitable mines was small. The Maine was the most successful, and the San Pedro, near it, probably stands next in productiveness. The Bronco, near Charleston, 7 miles away, is in siliceous schists, entirely surrounded by rhyolite. It is the oldest mine in all this region, having been a developed property before the outcrops of Tombstone were found. It has had a most checkered history, and is now- worked with more vigor than ever before. In general, I be- lieve the veins in the rhyolite have had rich ore, but have been

small and irregular.

Faults.

One of the curiosities of Tombstone is a fault in Emerald gulch with shale on one side and caliche on the other. Its strike is N"..82° E., dip E. 80°. A shaft in it is 20 ft. deep, with- out disclosing the ftill extent of the throw. This interesting fault is shown in Fig. 12. It is marked by the usual zone of laminated or crushed material, which contains both caliche and shale fragments. As the caliche is entirely a product of local erosion and modern calcareous cementing, and must have been formed since the time of powerful erosion, this fault, which seems to be equal in throw to others in the district, must be quite recent.

Thb Tombstone, Arizona, Mining District.

Fio. 12.

On the hill back of the Grand Central mine there is an open ereviee which is said to have opened, or at least enlarged, within recent years. It is therefore commonly attributed to the caving of the stopes in that mine, its strike, N. 32° E., being about the same as that of the ore-bodies. This explanation is not satis- factory, for the thickness of rock between it and the stopes would, in this locality of shaly quartzites, be sufficient to fill the widest stopes of the Grand Central without producing any effect upon the surface. The paral- lelism between this open fissure and the caliche fault is suggestive. They are about 3000 ft. apart, the crack being nearly due north from the fault

There are several faults in the district, but none of moment. The largest vertical fault known is in the Empire part of No. 6 anticlinal, oO ft. The Quarry anticlinal is faulted 35 ft. Of cross-faults, the best known is on the Contention- Head Center line, where the dike and vein have been shifted 120 ft. horizontally. There is also a small horizontal throw of 20 ft in the Empire dike, and others noticeable in the outcrops of the shale lime- gtones- The anticlinal faulting pre- ceded the deposition of ore. In the Empire there is ore under the shale on the upthrow side, but none on

the downthrow side. In the Quarry fault there is ore on both rides, but here we have not only one of the strongest anticlinals in the district, but a dike just through the outcrop. There is no sign of an ore-body faulted after its deposition. The dikes do not seem to have caused faulting, no instance of it being known. The torsion-crevices, on the contrary, frequently faulted the ground. In the Hoodoo stopes there is occasionally a jomble of limestone and quartzite blocks, but with small throw. The Head-Center fault is interesting because it is ▼oi. xTxm. — 3

Fault between Shale and Caliche in Emerald Gulch.

84 The Tombstone, Arizona, Mining District.

closely parallel to the West Side compression-fissure and crosses the Contention vein at an angle of 80°.

"With this example of faulting in a crevice, it is somewhat remarkable that the West Side fissure shows no faulting, but abundant disproof of it. There is some slipping of slabs on each other, but very little, and the bedding-lines across the drifts prove that there has been no general movement. The West Side and Contention represent the strong lines of com- pression-fissuring, and no faulting along their lines is known.

Ratio of Gold and Silver.

The entire yield of Tombstone is estimated at 168,000 ounces of gold, 21,500,000 ounces of silver, and 5000 tons of lead. The losses by pan-amalgamation, which was the method by which most of the product was obtained, would require an addition of 15 per cent, to the gold and silver to obtain the gross total of these metals, making somewhat more that 187,000 oz. gold, and 22,500,000 oz. silver. The proportion of gold was, therefore, only 0.827 of one per cent., by weight, of the pre- cious metals.

The total value of all products as marketed was about $25,000,- 000, to which about $4,000,000 must be added for losses, and somewhat for unreported product. Some mines report only their net returns, leaving the expenses of marketing to be sur- mised, though they belong to the net yield.

The mines varied extremely in their proportions of gold and silver. The Contention and Grand Central produced about 20 gold to 80 silver, by value, which corresponds to about 1 ounce gold to 80 ounces silver, as the latter metal was worth about at that time. Other mines show a much smaller proportion, the Tombstone Mill and Mining Company having 1 gold to 180 silver, and in mines which were confined entirely to superficial deposits in limestone the proportions may have fallen to 1 : 400 by weight.

The relative proportions of gold and silver in the ore forms one of the most interesting and important problems of the dis- trict, and there are indications that a favorable change is taking place with depth. The gold value was greater in the fissure- veins than in the aitticlinal deposits, and it improved in both going downward.

In the Contention, a drift run for a length of 140 ft. about

The Tombstone, Arizona, Minino District. 85

SO ft. below the water-level gave an average assay of more than |100 per ton in gold, and this was in an anticlinal deposit The condition in the vertical bodies is not reported. In the West Side the ore found at the lowest points mined in the an- ticlinal, 1150 ft. from the vertical vein, yielded $17.20 per ton 88 the average of 55 shipments, which is probably four times the average of the West Side vein near the surface.

The same increase is found in both vertical and fiat deposits. The Lucky Cuss, which had little more than a trace at the sur- face, produced ore worth $12 a ton below the water-level, and the last two shipments contained 1.7 ounces, or $85 a ton. The lowest ore of No. 6 anticlinal yielded 1.63 ounces, or $33.58 per ton, as the average of 71* shipments. The ore now mined in the Tranquillity is also rich in gold.

While these are merely specific instances, we obtain from the books of the Tombstone Mill and Mining Company a com- parison of the product by periods, which is more exact and also more instructive. From June, 1879, to March, 1884, inclusive, that company produced 10,931 ounces of gold and 3,459,555 ounces of silver, or 1 : 317. From March, 1884, to December, 1893, the product was 26,745 ounces gold and 3,247,603 ounces silver, or 1 : 121, the proportion being 2.6 times as high in the second period as in the first. The only mine opened from the grass roots in the second period was the Lucky Cuss. All others were opened in the first period, and had their deep mining in the second period. This company mined two fissures and nearly all the anticlinals in the camp, and its results must be received as representative of the true conditions in the district This increase of gold with depth is as interesting in a scientific sense as it is important to the future prosperity of the district. If I understand Prof. Com stock* correctly, he ascribes this increase in gold tenure to impregnation following an ancient uplift and folding, which was succeeded by a later uplift that brought in silver, the latter being geologically higher than the ores of the first deposition.

Confining myself to this district, without considering evidence to be obtained from other districts in Arizona, I do not find fiu2tB at Tombstone to sustain his view. There have been two well-marked periods of folding there. One preceded the

"The Geology and Vein-Phenomena of Arizona,'* IVans,, xzx., 1038.

86 The Tombstone, Arizona, Mining District.

intrusion of the granodiorite ; the other came after the intrusion, and crowded the strata against the eruptive mass, producing effects strongly marked in its neighborhood ; but I see no evi- dence of different ore-depositions after these- events. The en- trance of all the ore was later than the second folding. The difference of level in the Goodenough incline between the poorer gold-ores of the surface and the richer of the Empire is less than 300 ft., the continuity of the ore is complete, and the ore itself is as uniform in character as oxidized ores ever are.

Roughly speaking, about half the gold and silver produced in Tombstone has been taken from the upper shales, about a third from the blue and white limes, and most of the remainder from the Lucky Cuss limestone at various points of its exten- sive outcrop. The quartzites over and under the white lime have carried the least ore, but neither of them has been reached in the larger fissure-veins which have had richly paying ground in the quartzite included in the upper shale. The Toughnut quartzite was ore-bearing in the West Side mine.

The town of Tombstone occupies a flat gravel mesa, or table, quite level for a width of a third of a mile from north to south, and sloping gently to the west for a mile and a half. The gravel lies on the anticlinal shown on the extreme left of Fig. 4, and the white limestone of Combination and No. 6 antieli- nals outcrops on the southern side of the town. Toughnut gulch is a natural boundary on that side, and, with the excep- tion of Comstock hill, the rock exposures stop at the gulch. Some do not reach it, being covered by gravel. To the north is a waste of gravel, which a shaft near the town penetrated for 800 ft. without reaching rock.

After lying idle for several years, the reopening of the Tombstone mines has been undertaken by gentlemen who were prominent in the early mining of the district. A new shaft, with two hoisting compartments 4 by 7 ft. and two pump compartments 5 ft. 9 in. by 7 ft., has been sunk near the Con- tention fissure, and has reached the water-level at a depth of 569 ft;. This work was done and the shaft strongly timbered in less than five months. Pumps to throw 1750 gallons a minute will be installed. It may seem remarkable that pumps of such capacity should be needed in a region that is not only

The Tombstonb, Arizona, Mining District. 37

arid, but one where the underlying rocks receive an unusually small part of the rain that falls. The caliche which Prof. Blake deBcribed in a recent paper* covers a large part of the district and sheds the surface-water, and the run-off is abnor- mally large. The calculations are made on the results of pumping done in 1884, when about 1,500,000 gallons a day were thrown out The water has never returned to its old level by 6 or more feet; and, though there is a great body of water in the ground, it is believed that, when once removed, the rocks will be permanently dry.

The water-level on the west side of the granodiorite is about 250 ft. higher than on the Tombstone side, which may indicate a great depth of rhyolite between the mines there and the San Pedro river, 6 miles distant and 400 ft. lower.

One of the principal objects of my examination of the Tomb- stone district was to ascertain what measures are likely to be encountered below the water-level. The presence of the "granite" formerly led to the supposition that it underlaid the town and ore-bearing rocks ; but the evidence contradicts that impression. The mines still have about 2000 ft. of known sedimentary rocks under them, and perhaps much more.

The revival of these mines is a matter of more than usual interest, for it is based upon convictions derived from a knowledge of the structural geology of the district, and this knowledge is in no sense a theory nor an ordinary scientific explanation, of facts. The mines in the anticlinals were man- aged for years in the light of this knowledge, and thousands of feet of drifting was done to reach anticlinals at the contacts of their rocks. The work began on a theory of Mr. Staunton's, but repeated successes soon lifted it from the plane of reason- ing to the solid basis of experience.

It is this experience which will guide operations in future, and the projectors have the greatest faith in their successful outcome. All the fissure-veins, all the most productive mines in anticlinals, and many of second importance, have been con- solidated in one ownership, as was necessary before a company could be formed to pay for draining the entire district.

Trans, f xxxL, 220.

88 Diatom-Barth In Arizona.

Diatom-Earth in Arizona.

BY W. P. BLAKE, F.O.S., DIRECTOR OF THE ARIZONA SOHOOL OF MINESr

Tucson, Arizona.

(New York and Philadelphia Meeting, February and May, 1902.)'

General Description.

Forty-five years have passed since I discovered the exten- sive and remarkable diatom-earth beds at Monterey, California and now I have the satisfaction of bringing to notice still another wonderful deposit in the heart of Arizona. The Mon- terey beds were described at the Philadelphia Academy,* and specimens were sent to Prof. J. W. Bailey, West Point, N. Y.,. at that time the leading American authority upon such micro- scopic relics of organic life.

The earth from both localities is snow-white and pulverulent.. It rubs ofl' like soft chalk upon the fingers when handled, and has the general appearance of chalk. But, unlike the Monte- rey beds, these newly-discovered deposits consist largely of vol- canic ash, through which the siliceous shells of the diatoms are distributed.

These deposits are in the central portion of the San Pedro- valley,t in the southeastern corner of Pinal county. The region of their greatest development is a few miles south of the mining town of Mammoth, on the east bank of the stream, and near Redington, some 40 m. N. of Benson, on the Southern Pacific railway. The altitude is about 2600 ft. above tide. This portion of the San Pedro valley lies between the high Catalina and Bincon ranges on the west and the G-aliuro mts* on the east The Catalinas are composed chiefly of crystalline

Proc PhxUu Acad, Nat /Sbi., vol. viL, p. 328 (1854-66); alao, Brt Oeol, conn, in Oalifomia in 1863 (4to., 1866 ; and in Poc. BR. Surv.f vol. v.).

t The Bio San Pedro of the early explorers and fathers is the Bio Qaiburi of the aborigines. The valley was explored in 1697 by two Spanish parties, united for the purpose, and accompanied by 30 Indian auxiliaries. They marched down the river to the Gila, and thence to Gasa Grande, returning up the Santa Craz. (See Bomcroffs History, vol. xvii., p. 365.)

Diatom-Earth In Arizona. 39

and gneiflsic rocks, and the Galiuros of rhyolite and volcanic tufiis. Both ranges are flanked by broad slopes and accumu- latioDfi of detrital materials, covering an older series of hori- zontal deposits, apparently of lacustrine origin, which are ex- posed in the eroded channels of the river and its chief lateral tributaries. At times of heavy rain-fall, the " wash " from the mountains often reaches the center of the valley, and over- whelms the bottom-lands and cultivated areas with a destructive avalanche of boulders, gravel and sand.

The diatomite beds are horizontal ; do not appear to have suffered any disturbance since their deposition ; and form the almost vertical walls of the chief lateral canons, attracting the eye by their snowy whiteness, especially where any recent ex- cavation or falling down of the cliff exposes a fresh surface. Dust and disintegration clouds the surface somewhat ; but the beds are always distinct in appearance from the red clays above and below them.

Xo distinct planes of deposition or stratification appear; and the specimens collected give no evidence to the eye of the existence of layers of stratification. They show a uniform white surface. But when the deposit is seen en masse in the arroyos and blufis along the canons, a difference in hardness, and probably in fineness, is shown by the unequal weathering. Evidently some of the beds are soiter than others, and yield more readily to erosion, thus disclosing a straticulate structure otherwise obscure. The lower portions of the deposit appear to be coarser than the upper layers, and to have more distinct partings of thin layers of clay; but these partings are not numerous.

It is not easy to determine the total thickness of the deposit, emce there does not appear to be any place where it is exposed in a continuous series from top to bottom. It disappears under the bottom of the canon ; and the upper surface appears to have been considerably worn away. The greatest thickness noted from the floor of the canon to the top of the beds was estimated at 100 ft This includes argillaceous beds at the base, and a few feet of superficial wash-gravel at the top. The beds in which the relics of the diatoms most abound are not less than 25 ft. thick.

Blocks of seemingly homogeneous snow-white diatomite can

40 Diatom-Earth In Arizona.

be quarried out, though the unweathered beds are somewhat tough. It can be easily cut up into slabs with a saw or knife. It is light and porous. Several blocks cut as nearly as possible into one-inch cubes were found to average 221 grains, or 14.335 grammes in weight, and to absorb as much as 75 per cent, of their weight of water. When wet, the material loses its white- ness and assumes a mottled greenish-gray color.

These determinations were made upon specimens from one of the lower and coarser layers.

Although to the unaided eye there is no apparent difference in the size of the particles from the different levels, all the specimens being white and soft, yet the touch reveals some coarser grains ; and particles of grit are found when a block is cut by a saw, and there is evidently a considerable difference in the degrees of fineness at different levels. By brushing the surface with a soft brush, the finer particles are gradually re- moved, and the coarser are left standing in relief, palpable to the touch and visible through a pocket-lens.

Under the microscope, the material is seen to consist, for the most part, of nearly colorless vitreous particles. It is appar- ently a volcanic ash or dust — or, rather, a comminuted volcanic glass — in minute transparent angular flakes, generally not more than 0.1 mm., but ranging from 0.1 down to 0.005 mm., and aver- aging, perhaps, about 0.05 mm. in diameter. Here and there in the mass, as spread out in the field of the microscope, appear particles, showing brown or dark-green color by transmitted light. These may be bits of obsidian, or possibly augite or hornblende. Since they can be readily concentrated by levi- gation, they are clearly heavier than the colorless glass-like particles. There are also small scales, apparently of a silvery mica.

Paljbontological Determinations.

In the midst of the finely divided vitreous particles, the higher powers of the microscope bring into view the beautiftil forms of the siliceous remains of diatoms.

Full suites of samples of this new deposit have been sent to eminent specialists, amongst them Dr. D. B. Ward, of Pough- keepsie, N. Y., Dr. Arthur M. Edwards, of New Jersey, and Mr. C. L. Peticolas, of Richmond, Va., all of whom express great interest in the material, and find in it many new forms.

Diatom-Barth In Arizona. 41

The Monterey deposit Dr. Edwards declares to be marine,* and similar in most of its characters to the celebrated stratum underlying the city of Richmond, Virginia.

In June, 1899, Mr. C. L. Peticolas, of Richmond, Va., wrote acknowledging the receipt of samples, and saying that they con- tained some undescribed forms and interesting variations from well-known ones ; also, that the earth resembled, in difficulty of treatment, certain apparently similar earths " from the far East which have been subjected to volcanic disturbances, and are probably mixed with sulphate of lime."t another place he said : " I have a sample from a deposit (recent) from Mobile hay which resembles that from Arizona."

Chemical Composition.

A chemical examination shows that the white earthy portions are chiefly silica with water, aluftiina, and a little lime. Carbonic acid is not present A quantitative analysis by Mr. H. A. Mann, Assistant in the Laboratory of the Arizona School of Mines, gave the following results :

Per cent.

Loas by ignition, chiefly water, 5.07

Insolable (SiO,), 82.81

Iron oxide, t 1*10

Alnmina, 4.84

Sodiam chloride, 0.45

Gaiciam oxide, 2. 10

Magnesia, trace.

Organic matter undetermined,

The loss by ignition varies in different samples. One determi- nation gave as little as 3.43 per cent.

The analysis of the Kichniond, Va., diatomite showed the presence of 8.37 per cent, of moisture, 75.86 of silica, and 9.88 of alamina. The diatomite of Storey county, Nevada (presum- ably the so-called "electro-silicon"), showed the presence of 18.44 per cent, of water (lost at red heat), 81.08 of silica, and no alumina. §

i4er. Jour. Sei., xlii. (Nov., 1891), p. 383.

t As to thia obeeryation, it is fair to Bay that tests of my Arizona material fail to show any sulphate of lime. t Determined as metallic iron and calcalated as FeOs. i Biart of the Eleventh Census of the U. 5.—'' Mineral Industries,'' p. 708.

42 Diatom-Earth In Arizona.

In the upper portion of a part of the Arizona deposit there is a siliceous layer of light olive-green opaline silica, very com- pact and dense, occurring in the midst of the white earth very much as flint occurs in chalk. It is nodular in form, and very irregular in its thickness. Upon ignition at a red heat, it gives- off water and loses 5.7 per cent, of its weight. Specific grav- ity, 2.08. It breaks with a conchoidal fracture, and is translu- cent on the thin edges. Before the blowpipe it blackens, and gives off an empyreumatic bituminous or smoky odor, indica- tive of organic matter. It decrepitates explosively, and, when heated to redness with access of air, gradually assumes a red color, due, no doubt, to the oxidation of the ferrous to ferric iron.

Diatoms a Possible Sourcb of Pbtroleum.

The occurrence in this deposit of diatoms of compact vitre- ous hydrous silica (opal-silica) the more interesting, inasmuch as layers of similar silica occur in the great diatomite beds at Monterey, and other points along the coast of California. I found there several layers of such silica, and noted also the fact that they were bituminous, yielding bitumen, as well as- water, by distillation in a tube.* Other compact siliceous masses of a darker color, thrown up by the waves on the beach at San Pedro, were recognized as bituminous and infusorial in origin, and as indicative of a submarine development of beds- like those at Monterey.f The possible diatomitic origin of bitumen and petroleum was thus suggested. The idea receiver support and confirmation by the recent discovery of petroleum in globules in the substance of diatoms at a locality in Texas,, described by Dr. Phillips, the Director of the Texas Geologi- cal Survey.

Samples of marine ooze, collected off the Sabine Pass, gen- erally showed the presence both of living diatoms and empty shells. In one sample, a large number of living diatoms were found. These were mainly of one species of Navicular with one of Pleurosigma. Both of these species contained relatively large globules of oil in their plasma. These oil-globules, espe-

Report of a Oeoloffical Reeonnainanee in Galiforma (W. P. Blake, 4to, 1855), pp. 178-179. t Ibid., pp. 181-182.

t ''Texas Petroleum/' by Wm. fiattle Phillips, Ph.D. No. d of the Univ. of Tex. (1901), pp. 20-28.

Diatom-Earth Ik Arizona.

dally abandant in the Navicular were of various sizes and irreg- ularly distributed throughout the body of the diatom. Mr. Wm. W. H. Long, Jr., who made the microscopical examina- tion and a report, says : On the death of the diatom the oil- globules seem to separate from the other contents of the shell,. and finally to pass out of it"

Befeiring to the experiments of Kraemer and Spilker, and to the extraction by them of a brownish-black wax-like mass together with sulphur, from peat. Dr. Phillips observes :

It shows that the power of certain diatoms to secrete oil is clearly allied with the power to secrete organic compounds of salphur ; the salphar and the oil being present together. Furthermore, this power of selective absorption of oil sod salphur by these diatoms may be compared with the absorption of nitro- gen and nitrogenous compounds by baeiUi attached to the roots of certain plants, such as doTer, peas, etc In the case of the fixation of nitrogen by bacillij we bsTe one of the most beantifnl illustrations of the power of obscure forms of life to influence Tegetable growth, and even to condition it. In the case of the diatoms which absorb oil and sulphur compounds we have a fruitful suggestion of the origin of petroleum and its association with sulphur.''

Lacustrine Origin.

The lacustrine origin of the Arizona diatomite deposits is shown by the diatoms and the fineness of the volcanic ash, proving the absence of strong currents and the existence of quiet and. deep water. The thickness of these beds of ex- tremely fine materials indicates also a long period of quies- cence, and the absence of floods of muddy water. It is scarcely conceivable that such accumulations of clean, white volcanic ash could have been made by the transporting power of water; for currents which could have carried the ash could at the same time have carried considerable fine clay. Moreover, the mate- rial would have undergone a sorting action, to which it does not appear to have been subjected. Heavy and light particles tre intermingled, though easily separable by slight washing.

The source of the ash must have been eolian. There must have been copious and long-continued showers of volcanic ashes, to form a deposit of such great extent and thickness. I have elsewhere noticed the evidences of lacustrine conditions along the San Pedro valley, and stated the probability that the extensive red-clay-deposits were laid down in a lake, or in a nearly land-locked estuary far in the interior, remote from

44 Diatom-Earth In Arizona.

active tidal action. In such an estuary there would be a ming- ling of salt and fresh water, permitting such a mingling of salt- and fresh-water forms as we find in the deposits.

K this is the correct view of the former conditions, the drainage of the valley, as of other nearly parallel valleys in Arizona, was the result of a general or epirogenic elevation in the late Tertiary or Quaternary, such as drained the great in- terior valley of California.

Other Localities of Volcanic Ash with Diatoms.

For a description of extensive beds of volcanic ash over a wide area, reference may be made to a paper by E. H. Bar- bour,* who describes beds in Wyoming, Nebraska and KauBas, several feet in thickness, containing also diatom-frustules and sponge-spicules. These beds underlie the loess, and extend throughout the Miocene (Oligocene) up to, and through, the Loup Fork beds.

The material is white and fine in texture, and is used locally for polishing purposes, and as a scouring-soap, or as a substi- tute for pumice. The figures given by Mr. Barbour show that the forms of the particles are like those of the Arizona de- posits, being sharp, angular, flake-like chips, generally less than one millimeter in diameter.

Thick beds of soft, white diatomite are quarried in Nevada, near the old road from Carson to Virginia City.

Extensive beds, occurring in Alaska, have been noted by Schwatka, McConnell and Russell. The ash on the Upper White river has been specially studied by Dawsonf and Hayes, t The latter estimates the area of distribution of the tufaceous ash to be more than 52,000 sq. m. The greatest thickness ob- served was between 75 and 100 ft. Brooks§ found this white volcanic ash on the White river, where a bed a few inches thick was overlain by 6 in. of soil. On the Snag river he found a thickness of 3 feet. He describes the material as a finely- comminuted white ash, seemingly made up entirely of vol-

Both well' 8 Mineral Industry vol. vi., p. 22.

t " Report on an Exploration in the Yukon District,** Oeol, and Nal. Hist. Sur- vey of Canada vol. iii., Part I., Report B (1887).

t "An Expedition through the Yukon District,*' Nati. Qeog, Mag. iv., 147.

J Reconnaissance in the Tanana and White River Basins, Alaska, in 1898," by Alfred Hulse Brooks, U, S, Qed. Sur., Twentieth Ann. Rq)Lf Part VII., p. 475.

Diatom-Earth In Arizona. 45

canic glass. The coarsest grains varied from 0.5 to 1 mm. in diameter.

Uses and Value.

Diatomite and the associated volcanic ash have a variety of economic uses. Diatomite (known also as infusorial earth, or diatomaceous earth, and by the Germans as kieselguhr) is usu- ally classed among the abrasives, such as tripoli, rotten-stone, etc. It is largely used as a polishing-powder. The white earth from near Carson, Nevada, sold under the trade-name of "Electro-Silicon," is an example. The Arizona earth, if cleaned by elutriation from coarser materials, such as grit and the larger flakes of volcanic glass, makes an excellent polish- ing-powder for metals, including silver.

Its use in the manufacture of dynamite as an absorbent or "dope" for nitro-glycerine is well-known. It has been suc- cessfully employed as a non-conductor of heat for coating steam- pipes and boilers ; and could doubtless be used to advantage in the manufacture of safes. It is applied in coating steam-pipes by the California Anti-Caloric Co., and is valued for that mar- ket at per ton on the surface at the mine, and f 18 per ton at the works in San Francisco. In 1897, a deposit was opened at Lompoc, Cal., and about 500 tons were shipped from there.*

The production of diatomite in the U. S. ranges in the neighborhood of 3000 tons annually.

Secbbtart's Note. — For more exact and detailed paleonto- local descriptions, with figures by Dr. Ward, etc., the reader may be referred to a paper by Prof. Blake, about to be pub- lished (June, 1902) in the Transactions of the Wisconsin Academy of Sciences. — R. W. R.

IlKneral Industry yol. vi., p. 16.

46 Htdrostatio Lbvbl Attained By Orb-Dbpositing Solutions.

The Mineral Crest, or the Hydrostatic Level Attained by the Ore-Depositing Solutions, in Certain Mining Dis- tricts of the Great Salt Lake Basin.

BY WALTER P. JENNEY, E.M., PH.D., SALT LAKE CriY, UTAH. (New York and Philadelphia Meetinjc, February and May, 1902.)

In the limestone area of Tintic and other mining districts of the Great Basin region of Utah, it has been observed that surface-outcrops of ore occur but seldom, and are mainly con- fined to points of relatively low elevation, where the veins cross some basin or ravine. Nowhere does a considerable body of -ore outcrop on the tops or high up on the slopes of the hills.

Mining operations, on the other hand, have shown that large -and continuous ore-deposits frequently occur in depth in the limestone, beneath large masses of barren rock. Such ore- bodies, when followed upward in the lodes, are found to termi- nate at well-defined levels, without reaching the surface. Yet the minerals-bearing fissures themselves extend above the top of the ore, being often traceable, though barren of all valu- able minerals, for hundreds of feet above the stopes in the mines, and even observable in outcrops at the surface.

This abrupt cessation of the ore at a uniform horizon does not appear to be connected with any change in the country- rock adjacent to the lodes. The strata above and below this horizon seem to be in every way equally favorable to ore-depo- sition. Explorations above it have developed an open-fissured country, barren not only of ore, but also of indications that minerals bearing gold, silver, lead or copper were ever deposited in the strata at that elevation.

The height reached by the ore, while usually constant throughout the length of a given lode, may vary in particular sections, from the operation of local causes. Each lode in a district has its own distinct horizon, above which the ore- deposits do not extend. Where the ore-bodies are continuous

fiTDEOSTATIC LEVBL ATTAINED BY ORB-DBPOSITINO SOLUTIONS. 47

for a long distance on the strike, and other conditions are uni- form, the top or apex of the ore is nearly level or gently undu- lating; but more commonly its upper surface is broken into a of peaks and pinnacles, alternating with flat summits and wave-like crests, reaching up from the main ore-channel to practically the same relative altitude, and forming the ore- terest or mineral crest of the lode.

Examination discloses in these mines many evidences that the terminal edge of the ore nearest to the surface represents, sabstantially, the height to which the mineral-depositing solu- tions ascended in the fissures during the period of ore-formation; an other words, that the present ore-crest is the high-water mark, or ultimate level, reached as the result of the ascensional force of the heated ore-bearing waters.

In some instances, lines of extinct mineral-vents, nearly over the ore-bodies, on the surface, mark the course of the lode. These are small local outcrops of quartz, chalcedony, siderite, ankerite, barit, and other gangue-minerals, seldom carrying more than traces of the precious metals. It is not improbable that, during the period of ore-deposition, these vents were geyaer-like pipes or channels, extending from the ore-deposits, hundreds of feet below, up through the non-mineralized strata to the surface, and constituting points of escape for steam and gases liberated by the chemical reactions incident to the formar tion of the ore. Surface-explorations of some of them indi- <ate that they were channels of up-flow for the waste waters expelled by the pressure of the steam and gases, after the depo- sition of the ores in the deeper strata. Among other evidence supporting this view is the occurrence in thick, banded sheets, lining crevices and open channels in these outcrops, of white, translucent chalcedony, a mineral deposited by hot silica-bear- ing waters.

To better understand these peculiar phenomena, it is neces- sary to consider the conditions attendent upon their formation. The earlier volcanic disturbances of the region are regarded as the direct cause of the elevation of the districts and the up- turning of the sedimentary rocks, producing the numerous small mountain ranges and solitary island-like upheavals which illustrate the varied types of the Basin Range structure.*

Bee Lake BonncviUe," by G. K. Gilbert and others, Monograph I. (1890) ; alio other monographs of the U. S. Geological Sarvey.

48 Hydrostatic Lbvbl Attained By Orb-Dbpositing Solutions.

These earlier disturbances were followed by a long period of comparative rest, during which a wet climate prevailed and an extensive erosion of the exposed strata occurred, carving the surface of the districts to nearly their present contour. There were the same low mountain ranges, with spurs projecting like promontories into the sands of the desert, their steep slopes deep-cut by narrow, rocky ravines, or scooped out in basin- formed gulches.

Later disturbances, deep-seated in the earth's crust, formed the vein-fissures and induced the deposition of the ores, at a time when the topography of many of these mining districts varied little from the present surface. The recent erosion, which has taken place since the deposition of the ores, has probably not removed, even on the more exposed slopes, more than 100 to 200 or 800 ft. in depth of rock-surface. This preservation of the ancient topography has been due, in great part, to the change in climate. In the present extremely dry period, surface-erosion is reduced to a minimum. So little are the outcrops of the ore-bodies eroded, that the conclusion seems inevitable that the present arid climate has prevailed continu- ously since their formation.

In such districts, the outcrop, or intersection of the vein- fissures with the old surface-erosion, would be, in profile, an irregularly broken or serrated line, rising from the lowest points, where the fissures crossed some deep ravine or basin, to summits where the fissure-belt cut through the tops of the hills or divides. Under these conditions, the mineral solutions, forced upward in the fissures, found outlets of escape at places of relatively low elevation along their course, with a consequent reduction of head or hydrostatic pressure so great that, no matter how open the fissures, or how favorable the ground, no considerable deposits of ore could be formed above a certain level, depending upon the elevation of the outlets and the vol- ume of the discharge, through them, of the heated waters, with the accompanying steam and gases.

Not only has the hydraulic head been controlled by outlets to the surface, but the escape of the solutions from the fissures into the walls and into the country-rock adjacent, especially in mines in limestone, has also acted to some extent in the same way. The slow circulation of the mineral-depositing solutions

Htdbostatic Level Attained By Ore-Depositing Solutions. 49

through large caves or chambers, or through the interspaces iu great masses of brecciated rock, from the extent of surface exposed and the free escape of steam and gases, has caused a reduction of both temperature and initial pressure.

During the long period of ore-deposition, fluctuations caused bj any increase or diminution of pressure or of temperature in the ascending waters would naturally occur in the hydrostatic level. It must have been subject to various accidents, such as the opening of new outlets at lower levels, or the choking or closing, by any cause, of outlets long in action. Moreover, the upflow through the fissure would be modified by crustal move- ments opening or closing its channels, and thus affecting both its volume and its pressure. Many other factors — for instance, the specific gravity of the solutions and the proportion of steam and gases mingled with them — must have had their effect.

The mixture of a liquid with a gas reduces the weight of a given column; and, when this column is under a hydraulic head not thus affected, this reduction of its weight is equivalent to an increase of pressure, in augmenting its flow. Friction pro- duces a loss of eflective head, which rapidly increases in con- tracted or tortuous channels, and must become very great where the solutions spread out and transverse the interspaces of frac- tured or brecciated rocks.

Since the completion of the primary ore-deposition, oxida- tion and re-formation of the minerals have tended to move the ore-crest downward in the fissures; but the quartz and other giuigue-minerals remain, together with oxidized ores in such quantity that there is usually little difi[iculty in determining the original crest-level.

In most mining regions erosion has been so great, since the period of mineral-deposition closed, that many hundreds and often thousands of feet of strata have been removed, destroy- ing all record of what occurred in the upper parts of the veins. 80 far as observed by the writer, mineral crests such as have been described above occur only in those districts in the Basin Region where, at the time the ores were deposited, the surface was deeply cut by erosion, and the later climatic conditions have been such as to preserve the old surface with little altera- tion— a combination of conditions which must be regarded as exceptional.

Vol. .— 4

50 Thb Beactions Of Thb Zibrvogbl Pr0Cb8S

Now that attention has been drawn to this subject, it is not improbable that like occurrences will be found in other mining regions of the world ; and we may certainly look for the dis- coveries of similar deep-seated ore-crests not formed and deter- mined chiefly, or at all, by the position of surface-outlets, but due to the inadequacy of the initial pressure of the heated waters to force them to the surface — a condition comparable to that of many artesian basins, where flowing wells do not exist, because the hydrostatic level is underground.

The observations of the writer indicate that ore-crests are not confined to veins or lodes of replacement in limestone, but may occur in fissure-veins in quartzite, and in lodes traversing eruptive granitic rocks.

The Reactions of the Ziervogel Process and Their Temperature-Limits.*

Bt Bobbbt Henrt Bradford, B.S., Universftt Of Utah, Salt Lake

Cfty, Utah.

(New York and Philadelphia Meeting, Fehraary and May, 1902.)

This investigation was undertaken at the suggestion of Prof. Henry M. Howe, of the Department of Metallurgy, Columbia University, who, in a letter to the author, dated October 23, 1900, wrote as follows, suggesting the subject of this disser- tation :

''The extraction of silver from copper mattes by either the Ziervogel or the Augustin process depends upon converting the silver into silver sulphate by means of the sulphuric anhydride evolved from the decomposition of ferrous sul- phate and cupric sulphate, which are formed during the roasting operation itself from the iron and copper sulphides present.

" It occurred to me, some time prior to the autumn of 1897, that these pro- cesses might be made much easier by adding to them, at the proper stage, fer- rous or cupric sulphate, or both, in the form of green or blue vitriol. That is, instead of having to rely solely on our ability to generate these sulphates in this very delicate roasting operation, my idea was that we could add a small quantity of already- prepared sulphate at the proper state of roasting, viz., at or before the period when the sulphatizing of the silver occurs.

This paper was submitted as a thesis for the degree of Doctor of Philosophy at Columbia University, New York City ; and at the same time accepted by the American Institute of Mining Engineers for publication in the TranBodioM of that Society.

And Thbir Temperature-Limits. 51

"Besides iron and copper snlphates, I have also thought of the addition of slkilioe sulphates for the same purpose, especially of sodium sulphate, which ii been used for sulphatizing copper in roasting.

'4t seems to me that the Ziervogel process, either alone or jointly with the AognstiD prooeasy would form a very useful and interesting subject for your thesis, especiaUy if studied with a view to determining the ranges of temperature and other conditions most favorable to the formation, and those which cause the decomposition, of ferrous, cupric and silver sulphates respectively ; including in joor investigation this idea of facilitating the sulphatization of the silver by the addition of green or blue vitriol or sodium sulphate, or two or all of them.

"In doing this I should like it distinctly understood that the work is to be done purely for the advancement of science, and that, if any useful result is xeKhed by the experiments, it is not to be patented by either of us, but is to be poUished at once for public benefit.''

The author would express the deepest gratitude to Prof. Howe for the constant interest he has taken in the progress of the work, and for the valuable counsel he has given on lines of investigation.

The Ziervogel Process.

The Ziervogel process was invented in 1840* by Hiitten- meister Ziervogel, of the Gottesbelohnungshutte, and was first brought into use in 1844, at Mansfeld, Prussia, by its inventor. Since that time it has been applied more or less continuously at Mansfeld, and at various other places in Europe and in this country, for extracting silver from copper-mattes.

This very simple, though delicate, process depends upon the fact that the silver in copper-mattes is converted into silver sul- phate by means of the sulphuric anhydride evolved from the decomposition of iron sulphate and copper sulphate, which are formed daring the roasting operation from the iron and copper sulphides present in the mattes. The process consists in roast- ing the sulphides in excess of air, so that they are oxidized partly to sulphates, which are then heated sufficiently to de- compose the sulphates of iron and most of the sulphates of cop- per, while the silver remains sulphatized, and may be dissolved out with boiling-water and subsequently precipitated on metal- lic copper. Simple as it appears, this process is extremely dif- ficult to execute, for it requires a very high degree of skill to aeize the exact period when the iron and copper sulphates are converted into their insoluble higher oxides and none of the silver sulphate is decomposed.

Lamborn, MetaUurgy of Copper p. 147.

52 the reactions of the zibrvogel process

Object op This Investigation.

This investigation was undertaken with the view (1) to deter- mining the conditions most favorable to the formation and those which cause the decomposition of the sulphates of iron copper and silver respectively ; and (2) to finding out if these processes might not be made much easier by adding at the proper stage ferrous or cupric sulphate or an alkaline sulphate. Instead of having to rely solely on our ability to generate and control the sulphates in this very delicate roasting operation, could we not add a small quantity of some sulphate at the proper stage of the process, and thereby get the desired results ?

Steinbeck's Experiments.

Steinbeck,* in 1862, carried out a series of most valuable ex- periments on the chemistry of the Ziervogel process as then operated at Mansfeld ; and his dissertation is to this day consid- ered classic. He attempted to ascertain approximately the tem- perature at the various stages of the operation, but the lack of suitable means for accurately measuring high temperatures made it impossible for him to get reliable results. To show the limitations under which he worked, I quote from Steinbeck :f " Lacking a pyrometer, with the help of which high tempera- tures could be determined with certainty, I contented myself in approximately determining the temperature of the heating charge by means of metals with well-known melting-points. These were exposed continuously for 5 to 5J hours during the roast in the upper hearth in a spoon 2" x 2", made of sheet- iron. By means of a cover made of a non-conducting substance, the heat from the gases near the arch of the furnace was kept out. The cover was made of two concave pieces of porcelain placed together, with their concave sides toward each other and with wood-ashes between them, the two parts being held to- gether by wire. The fusion was thus accomplished through the temperature of the roasting mass, as the crucible was continu- ously moved back and forth in the roasting-material." Table I. gives the metals and their melting-points used by Stein-

ChemiachrAnalytitehe Unterauchungen uber die Verdnderungmf weleke der Jfons- fdd&r Kup/erstein bei seiner Boshing bekvfs EnisHherung dureh die Ziervogscke Ex- tracHowmethode erleidet Dr. G. V. A. Steinbeck. Also, ZeiUehr fur das Berg- Huttetif und SaUnenwesen in dem Preussiehen Staate, vol. xi.. No. 2, p. 95.

t Oumisch-Analytisehe Untersuehungenf etc., p. 48.

And Thbir Temperaturb-Limits. 53

Table I. — MdHng-Points.

t I Tin.

rd by Steinbeck 235'' C

Obtained with improved pyrom- 1

Bismuth. Lead. 1 Zinc. I Antimony.

C. I 426 C. C. 630° C.

beck, and also the melting-points as determined by the use of improved pyrometers.

With some of the metals no grave difference is noticed on comparing the melting-points employed in his experiments with those recently determined ; but in the case of antimony the error is seen to be more than two hundred degrees. Hav- ing adopted so low a melting-point for antimony, Steinbeck was led to erroneous conclusions as to the temperature in various stages of the roasting operation, as instanced by the following statements : " At the expiration of one hour and fif- teen minutes the entire roast was of a dull-red color ; yet it was not able to melt antimony (425° C), while zinc melted readily. Also, at the last stage of the roast in the upper hearth, antimony was not fused; after three hours roasting, and after keeping the pan one-half hour in the roasting mass, antimony was still brittle, and could be broken with the pincers, and no trace of fiision was perceivable. On the other hand, zinc could be readily melted to the last moment the matte remained in the upper hearth. From these results, it follows that the tempera- ture which the roast attains in the upper hearth lies between the melting-point of zinc and antimony, and consequently can- not rise above 425° C."

Undoubtedly the temperature had risen above 600° C. during the roasting in the upper hearth, instead of remaining below 425° C; for the temperature of" dull red " referred to is given as 550-625° C. by Prof. H. M. Howe,t and 566°-635° C. by White and Taylor. J Concerning the higher temperatures in the lower hearth, he says : " After the mass had been in the lower hearth, whose arched ceiling and side-walls glowed with a bright-red heat from the Feuerungsperiod ' of shortly before, for ten minutes,

Le Chatelier and Boudonaidi Meaure dea TemprcUures UevieSy p. 11. Also, Bigk Temperature Measvremenis (a translation of the above by Burgess), p. 208.

t H. M. Howe, Eng. aiid Jfin. ,, Jan. 20, 1900, p. 75.

J i4iiL Soc. Meek, Enffineers, Dec., 1899, or Eng. and Min, Jour., Dec 23,

54 The Reactions Of The Ziervogbl Process

antimony (425° C.) was easily brought to fusion. This tem- perature was greatly exceeded with the roasting mass, but could not be determined, even approximately, for want of metals or alloys with suitable melting-points, but allow it to be approxi- mately estimated at 500° to 550° C." He found that, when antimony was first melted, dehydrated copper sulphate placed in a closed crucible was not decomposed, but retained its white color. Later, this sulphate was decomposed readily on the side of the hearth next the fire.

Apparatus Employed in the Present Experiments.

The improvements in pyrometry of the last few years have made it possible to determine accurately the temperature at any stage of the roasting process. The pyrometer employed ia this investigation was the Le Chatelier thermo-electric couple connected up with a d'Arsonval galvanometer mounted on a stone slab arranged on brackets against the wall of the labora- tory. The telescope with graduated scale was mounted on the same slab, two meters distant from the galvanometer. The ac- curacy of this type of pyrometer at high temperatures, and it& adaptability for use with small quantities of the substance heated, made it especially applicable to the work in hand.

The Howe electric furnace* used in this investigation was of inestimable value in many of the experiments. It furnished a means of controlling perfectly the temperatures of the heated substances. The material under treatment could be held at a definite temperature for an unlimited time simply by keeping the current through the furnace constant. The rheostats em- ployed in connection with the furnace are described below. Fig. 1 represents the furnace with crucibles prepared for the pyrometer couple and the substance to be heated ; and all parts- are shown in actual size. The body of the furnace was made up of two hemi-cylindrical blocks of magnesium oxide which, when placed together, formed a cylinder with a cup-shaped depressioix extending from the upper side. Inside of this depression the cylinder was grooved spirally. The platinum wires (two No. 1& Browne & Sharp gauge, twisted together) were wound into a spiral to fit this groove. Inside this spiral of heating-wire was

"An Electric-Resistance Magnesia Crucible-Furnace for Laboratory Use/*' by Dr. H. M. Howe, Trans., zxzi., £68; also Eng, and Min, Jour., Nov. 16 1901, p. 636.

And Their Tempbraturb-Limits.

placed the magnesium oxide crucible. Two shoulders forming an annular ring around the top of the furnace supported the cap or stopper. The pyrometer couple passed through the cap to the crucibles below. The furnace-body and auxiliary parts were of magnesium oxide. Powdered magnesium oxide formed the bed in which the inner platinum or porcelain crucible was placed.

Fig. 1.

Howe's Electric- Eesistance Magneeia Cracible-Fumace. A, Magnesia fomace-bodj ; B, Magnesia shoulders ; C, Magnesia cap or stopper ; E, Magnesia crucible ; G, Powdered magnesia ; B, Interior porcelain crucible.

The resistance of the furnace-wires varied with the temperature, ranging from 0.18 ohm at ordinary temperature of the room to 0.35 ohm at 1200° C. To maintain a temperature of 700° C. required a current of 27 amperes, while for 1000° C. a current of 32 amperes was necessary. The electric furnace was used almost every day, for a period of six months, without any ap-

The Reactions Of The Ziervogbl Process

parent deterioration of the platinum wire, the outer walls, or the inner crucible.

The current was obtained from the direct-current dynamo which supplied the electricity for general use through the buildings of the University. The voltage (115) was much higher than required by the furnace, so additional resistance was introduced. Two rheostats were employed. One was of the cylindrical type designed and used by the Electrical Engi- neering Department of Columbia University, having a shifting- contact, to furnish steps. This rheostat consisted of 240 coils of " climax " resistance-wire of 8 mm. diameter, wound six coils to the linear inch around a length of 5-in. gas-pipe which had been previously covered with an insulating layer of mica and

Fig. 2.

Wan of Room

ArniDgement of Furnace and Rheostats.

asbestos. The ends of the resistance-wire were connected with binding-posts suitably insulated. An iron rod of f-in. diameter running longitudinally above the gas-pipe, and attached to the same by a support at each end, carried a sliding-brush in con- tact with the coils of the rheostat and with a binding-post above. The whole was mounted on four legs, and stood a few inches from the floor. The maximum resistance of this one was 0.8 ohm at the temperature of the room. In con- nection with the necessary additional constant resistance, this rheostat with sliding contact was used to adjust the tempera- ture between the limits employed. The additional constant resistance was supplied by 72 ft. of German silver ribbon, 0.5" wide by 0.008" thick, strung back and forth from cross-pieces, 12 ft. apart, erected along the wall above the furnace. At one

And Their Tbmpbraturb-Ltmits.

cross-piece each end of the ribbon and each fold was con- nected by a large copper wire to its binding-post in the cross- piece. AdjustmentB could easily be made so that two, or four, or six of these lengths were in the circuit. With a current of 40 amperes, the ribbon diu not attain a temperature of visible

Fig. 3.

Gras Oven-Fumace.

redness, and did not oxidize to any extent. This simple and inexpensive rheostat was in use almost every day for six months, and was then in good condition. Fig. 2 shows diagrammati- the arrangement of the rheostats and the electric furnace. The furnace employed to roast the argentiferous matte was

58 The Rb Actions Of The Ziervogel Process

the American Gas Furnace Co.'s No. 4 Oven-Furnace. It shown in perspective in Fig. 8. The dimensions of the inner hearth were 18" x 24".

Methods Employed.

The experiments were begun upon pure sulphates of the metals iron, copper, and silver, respectively. In order to deter- mine at what temperatures these substances begin to decom- pose at atmospheric pressure by the agency of heat alone, each was taken separately and heated in the electric furnace until decomposition commenced. The thermo-electric couple of the- pyrometer was placed in direct contact with the sulphate under treatment. The dissociation of the compound was attended with the absorption of heat. This absorption caused the arrest or retardation in the rate of change of temperature of the sub- stance and couple, and the retardation was readily detected by the slower rate of movement of the galvanometer mirror of the- pyrometer. The pyrometer having been previously calibrated, — Le.j the relation of the amount of deflection of the galvanom- eter to the temperature of the thermo-couple having been ascertained, — the temperature at which the retardation oc- curred, which was the temperature at which the dissociation began, was thus easily recognized. As part of the sulphate was volatilized on dissociating, it was possible to confirm the results in each case gravimetrically. To confirm in this way, it was only necessary to take a fresh quantity of the sulphate and heat to a temperature just below the point indicated by the re- tardation, hold the temperature constant for some time, then cool and weigh. The balance, revealing no loss in weighty showed no change to have taken place. This was then heated a second time, this time to a temperature just above retarda- tion, and maintained there for a few minutes. The loss in weight showed definitely that dissociation had taken place. In some cases analyses were made of the residues, to give further evidence of the decomposition.

In order to determine what were the products of the dissoci- ation which began at a certain temperature, the substance wa& held at a temperature just a few degrees above that at which the reaction was seen to commence, until no further loss in weight was revealed. A constant temperature was maintained

And Thbir Tbmpbratu Re-Limits. 59*

ia the famace during this time, and the crucible and contents weighed at intervals. Many hours were often required for this condition of constant weight The amount of loss indicated the products of the change, and analysis of the residue con- firmed these indications.

It was found desirable to operate with small quantities in catching the exact temperature of retardation with the pyrom- eter. The couple could then be more conveniently placed in the layer of the sulphate next the crucible, in which layer the action of dissociation commenced. If the position of the point of contact of the couple in the sulphate was any appre- ciable distance from this first decomposing layer, the tempera- ture of beginning dissociation came high; this effect being due to the influence of the atmosphere of sulphuric anhydride which surrounded the particles of the mass after the layer next the crucible began to decompose.

Experiments with Copper Sulphate.

A quantity of neutral copper sulphate or blue-vitriol crystals, was dehydrated by heating to 850° C. and holding at that tem- perature for some time. The dehydrated salt was white, and remained so when kept in a stoppered bottle. A small amount of this dehydrated sulphate (CuSO) was placed in a crucible with thin walls and inserted into the electric furnace. The magnesia crucible of the furnace was filled half full of powdered mag- nesium oxide, and tde small porcelain crucible imbedded up to the rim in this powder (see Fig. 1), the idea being to get uni- form heating around the sides of the crucible. The contact of the couple of the pyrometer was made as short as possible, in order that the uppermost point of the contact should be im- bedded in the small amount of sulphate used. When the couple was in place, the heating-current of the furnace was turned on. Records of time and deflections of galvanometer were taken on blanks provided by the Metallurgical Depart- ment, as shown in Table 11.

If the conditions of the experiment were carefully arranged,. the retardation was decidedly marked, as is shown in the table. If for any cause the couple was not properly placed, the re- tardation came high, as already explained. As an average of a large number of such tests, the temperature of the first

Tue Reactions Of The Ziervogbl Process

Table II. — TmieDeflection Readings for OuSO.

Series 3. Nos. 1 and 2. Date, March 6, 1902. Object, Dissociation of CuSO. Beading hy R. H. Bradford. Record by R. H. Bradford.

Zero and

Cold Junction.

Interval.

Time Rising.

Deflec- tion.

Zero and

Cold

1 Junction.

Interval.

Time Rising.

Min. SecT

Deflec- tion.

Sec.

Min. Sec.

Galv. Deg.

sec.

Galv. Deg.

66

22 4-07

.7 '

36 57

retardation for dehydrated copper sulphate (CuSO) was found to be 653° C, and the inference was that this was the tempera- ture at which sulphate of copper (CuSO) begins to decompose by the application of heat alone.

In order to confirm this result, a weighed quantity (237 milligrammes) of the white dehydrated sulphate was placed in a small porcelain crucible, and the crucible and contents were introduced into the electric furnace and heated slowly to a temperature of 620° C. A constant temperature of 620° C. was maintained for five minutes ; then the crucible and contents were removed, cooled and weighed. No loss of weight was observed, and the mass was still white. Again it was heated slowly, and the temperature of 645° C. maintained for a few minutes. No loss of weight, and no change of color to be seen. At the next heating the temperature of 650° to 655° C. was maintained for fifteen minutes, and on cooling a change in color from white to yellow was to be seen near the sides of the crucible, and a loss in weight of 13.1 per cent, of the original sulphate was revealed by the balance. Fumes of sulphuric anhydride were seen to rise out of the annular opening around the couple at the top of the cap of the furnace during the last heating. From these tests dissociation was seen to commence at a temperature between 650° and 655° C. ; and the results con- firmed those obtained by the retardation of the pyrometer.

And Their Temperature-Limits. 61

To ascertain just how much of the sulphate would be vola- tilized at the temperature of 658° C, and in this way to deter- mine what the products of the dissociation were, 244 milli- grammes of the white dehydrated sulphate were placed in a small platinum crucible and heated to 655° C. to 670° C. for two hours, and until no white salt remained and no further loss could be gotten. The substance had changed color from white to yellow. The loss in weight was 60.5 milligrammes, or 24.8 per cent, of the original weight The experiment was repeated a number of times, and the average of the percentages of loss dne to the dissociation, which began at 653° C, was 25.04 per cent. The yellow salt did not change its color nor increase in weight from absorption of moisture from the atmosphere dur- ing four days that the substance was kept under observation. The yellow residues from two of these heatings were analyzed, and gave 53.5 per cent, and 53.12 per cent, copper respectively, with an average of 53.31 per cent It was practically insoluble in distilled water, changing to a green color after a few min- utes' time. From these tests the yellow residue was determined to be the basic copper sulphate of the formula CuO,Cu804, or

in which the percentage of copper is 53.13 per cent The the- oretical loss in weight of two molecules of the neutral sulphate in changing to the basic salt is 25.07, as compared with 25.04 per cent determined in these experiments. With the electric fiimace it was possible to control the temperature so perfectly as to get all the white neutral salt changed to the yellow basic sulphate before any black oxide of copper was produced. This method of obtaining the yellow basic sulphate of copper from the white neutral sulphate had been previously attempted, but without succe88.t This may be accounted for by the facts that the dissociation proceeds very slowly when the temperature is raised but a few degrees above the point at which the change begins; and that, at a temperature less than 50° higher, the yellow basic salt begins to dissociate with the formation ot black oxide of copper and sulphuric anhydride.

Itoseoe A Schoriemmer, voL iL, pt. i., p. 339.

t S. U. Pickering, Chemical Newt, vol. xlvii., p. 182.

Thb Rbactions Of The Ziervoobl Process

The speed of dissociation was much slower when the furnace was kept closed, so that the atmosphere within the crucible was -one of sulphuric anhydride, than when the furnace was open at the top, allowing the ingress of air. Even with an open fur- nace, considerable time was required for the action to become complete. If the material was heated rapidly, it was possible to raise the temperature many degrees above the point at which the decomposition commenced without effecting a complete change. If the gaseous products of the dissociation were rap- idly removed, the effect was to greatly hasten the operation. In roasting the argentiferous copper-mattes — especially was this noticed in the muffle-furnace — the speed of dissociation was* eatiy increased by providing for the rapid removal of the gaseous products.

Treatment of the YeUow Basic Sulphate.

Experiments were carried out with the yellow basic sulphate, obtained by decomposing the white neutral salt, in a manner similar to that already described for the dehydrated blue vit- riol. Small quantities were taken in a porcelain crucible and heated in the electric furnace with a uniformly rising tempera- ture. The point of contact of the thermo-couple was imbedded in the yellow powder next the crucible. The time-deflection readings are illustrated in Table III.

Table III. — Tme-Deflection Readings for CuOCaSO.

Series 4. Nos. 8 and 4. Date, March 8, 1902 Beading by R H. B. Eecord by R. H. B.

Object, CuO,Cua

O4 to CuO.

Zero and

Cold Junction.

Interval.

Time RiBlnR.

Deflec- tion.

Zero and

Cold Junction.

Interval.

Time Rising.

Deflec- 1 tlon.

Sec.

Min. Sec.

&-02

fr-07

Galv. Deg.

Sec.

Min. Sec.

Galv. Deg.

40 1 0-97

And Their Tempbrature-Limits. 63

Six different trials with the basic sulphate gave the tempera- tures of retardation as follows: 700° C, 703° C, 701° C, C, 700° C. and 703° C, giving an average of the six as C.

To confirm these results, a weighed quantity of the yellow alt was heated for ten minutes at a temperature of 690°-695° C, then cooled and weighed. No change of weight had oo- corred, and the color remained the same. This was heated again, this time to 705°, for 10 minutes. On cooling, a layer of black oxide was to be seen next to the crucible, and a loss in weight showed that the temperature of dissociation had been reached. A number of continued heatings at temperatures of 705**-720° C. showed that it was only necessary to allow suf- ficient time to effect complete change to the black oxide, as was indicated by the loss in weight and change in color, and con- firmed by analyses of the residues. Time was found to be an important factor in effecting the complete dissociation ; but, as wonld be expected, the time required was less, the greater the temperature of beginning dissociation was exceeded. With but one gramme of the basic sulphate in the crucible, the mass could be raised to 750° C, and still have the change to oxide incomplete. With 4 or 5 grammes of the substance, the tem- perature could be brought to 850° C. and higher, without com- plete change taking place. If the neutral sulphate were heated more or less rapidly, the dissociation into basic salt began at €53° C. ; but while this change was taking place, the atmos- phere of sulphuric anhydride evolved retarded the change of the basic sulphate to the oxide, so that a temperature above 702° C. could be obtained without the appearance of any black oride.

From these experiments on blue vitriol (CuSO + 5Aq), it is aeen that the neutral sulphate commences to change te the basic sulphate at the temperature of 653° U., and that cupric oxide begins to form at a temperature of 702° C. If these tempera- tures be but slightly exceeded, and if the sulphuric anhydride 18 not readily removed, the change is slow. A higher temper- Mure and a more open furnace effects a more rapid action.

JSxperiments with Ferrous Sulphate. A crystal of chemically pure green vitriol (PeSO + 7Aq), weighing 840 milligrammes, was heated in a small porcelain

The Reactions Of The Ziervogel Process

crucible arranged in the furnace in the same manner as de- scribed for copper sulphate. After dehydrating, the mass was pressed down onto the bottom of the crucible, and the junction of the thermo-electric couple was imbedded in the powder. The heating-current of the furnace was turned on, and the tem- perature rose slowly, though not so uniformly as in the case of the sulphates of copper. As a temperature of 585° C. was reached, a ret&rdation in the rate of heating was indicated, as shown in Table IV.

Table IV. — Time-Deflection Readings for FeSO.

Zero and

Cold Junction.

Interval.

Time Rising.

Deflec- tion.

Zero and

Cold Junction.

Interval.

Time Rising.

Deflec- Uon-

Sec.

Min. Sec.

Galv. Deg.

Sec.

MIn. Sec.

Galv. Deg.

51 1 .6 1

7-03 . .7 '

17 ! .8 32 .9 47 6.0 8-02 .1 17 .2 34 .3

The retardation is seen to be slight ; yet, from a number of concordant results, the retardation was observed to occur regu- larly at the same temperature of 590° C.

Attempts to confirm this result by heating weighed quanti- ties of the ferrous salt in an open crucible and noting the tem- perature at which loss in weight was first observed were not successful, owing to the fact that the ferrous sulphate tends to oxidize when heated in the presence of air. It was found that, after dehydrating, if the substance were heated to successive temperatures above 300° C, and held for half an hour, an in- crease in weight was observed in every case, until a tempera- ture of about 535° C. was reached. Above this temperature a reduction in weight was revealed. The amount of increase in weight for half an hour at 515° C. was only 1.03 per cent. A

And Their Temperature-Limits. 65

portion heated to 535° for twelve minutes showed absolutely no change in weight, and, when heated to 540° C for two and a half hours, gave a decrease of 5 per cent, of the original fer- rous salt employed. The rate of decrease was slightly greater at 550° C, and at 565° still greater. The tendency of the fer- rous salt to become oxidized in air accounts for the increase in weight referred to. The reduction in weight which began klow 590° C. was undoubtedly due to the fact that the ferric sulphates formed by the partial oxidation of the ferrous sul- phate dissociate at a lower temperature than does the ferrous salt itself.

To overcome the difBculty of oxidation which takes place in an open vessel, a sample of the ferrous sulphate was heated in a glass bulb-tube, three inches long, and drawn out at a point near the substance to an internal diameter of J of an inch. The bulb containing the substance was placed in the powder within the magnesia crucible of the furnace, and the other end of the tube extended up through the cap of the fiirnace. In this tube the oxidation was inappreciable. The weight remained con- stant, as shown by the balance after each successive heating of 10 to 20 minutes to temperatures between 500° and 585° C. When a temperature of 590° C. was reached, fumes of SO, ap- peared at the mouth of the tube. The tube was kept at 590° C. for 30 minutes, and then cooled and weighed, and a loss of weight showed the dissociation to have commenced. The loss was very slight, but a sublimate of sulphuric anhydride, which rapidly changed to sulphuric acid, was observed near the cooler end of the tube. The dissociation was extremely slow in this tube, as instanced by the fact that when the temperature was held at 625°-685° C. for 2 hours, a loss of weight of only 3 per cent, was effected. This showed the decided effect on the rate of dissociation of a dense atmosphere of the sulphuric an- hydride evolved.

Silver Sidphate.

Silver sulphate was prepared by dissolving pure metallic silver in boiling sulphuric acid and evaporating to dryness or until every trace of free acid was removed. A porcelain evap- orating dish was used, and care was taken not to allow the gas flame of the Bunsen burner to play over the dish. In the pres- ence of reducing-gases, the sulphate of silver was decomposed VOL. xxxni. — 6

66 The Reactions Of The Ziervogel Process

at a very moderate heat, metallic silver being deposited* Three grammes of the silver sulphate thus prepared were placed in a Eoyal Meissen porcelain crucible and heated in the electric furnace. The junction of the couple of the pyrometer was placed in direct contact with the salt for investigations up to a temperature near 850° C. For higher temperatures the couple was enclosed in a porcelain tube of f -in. internal diameter, 4 in. long, closed at lower end. The temperature rose uniformly until 660° C. was reached, when the substance melted, causing a decided arrest or retardation of the pyrometer. On cooling, the freezing-point of the sulphate was readily indicated in a similar way. The freezing-point came at 655° C.,* a few de- grees below the melting-point in every case. No further irregu- larity in the rate of heating and no disturbance in the liquid sulphate could be observed until a temperature of 1095° C. was attained. Here the liquid filled with bubbles, and quanti- ties of sulphuric anhydride were evolved. If the temperature were held at 1095 C, the evolution of gas proceeded rapidly until all was decomposed, leaving molten metallic silver in the crucible. But if the furnace was allowed to cool a few degrees, the reaction ceased, and the liquid sulphate again became qui- escent. The experiment was repeated a number of times, and the rapid evolution of gas commenced in each case at 1095° C. In the next experiments, to determine if any decompo- sition occurred when the sulphate was heated to, and main- tained at, temperatures below that of this rapid dissociation, 1.195 grammes of the sulphate were heated to 866° C. for five minutes. No metallic silver appeared, and the balance in- dicated no appreciable loss in weight. On heating to 970° C. for five minutes, the loss in weight amounted to 3.5 milli- grammes, or J of 1 per cent Again the mass was heated, this time to 1050° C, for five minutes. The loss was 25 milli- grammes, or over 2 per cent., and metallic silver appeared in globules around the crucible. A fresh quantity of the salt weighing 2.966 g. was heated for one hour and twenty minutes to a temperature of 900° C. On cooling, particles of metallic silver adhered to the sides of the vessel. The analytical bal- ance showed a loss of weight of 46 milligrammes, or 1.6 per

Caraelley gives the melting-point of the sulphate of silver as 654 ii= 2. Journal of the Chemical Sotndy vol. zxxii. (1878), p. 279.

And Thbir Temperature-Limits.

cent. On heating the same mass to 920 C. for an hour and thirty minutes, a thin layer of metallic silver covered the un- changed sulphate, which layer became somewhat thicker after heating to 945° C. for one hour. The loss in weight had now reached 6 per cent., showing one-fifth of the sulphate to be de- composed.

In order to determine whether the reduction of metallic jiilver at temperatures as low as 900° C. was not due to the re- action of the sulphate on the porcelain of the crucible, these experiments were repeated in a platinum vessel. The results with the platinum vessel confirmed those with the porcelain crucible, and are given in Table V., along with those with the porcelain crucible.

Table V. — JRcUe of Dissociation of AgSO at Different Temperatures.

, 1 Kind of I4.I Crucible.

Temp, to which

SubstaDoe

was

Heated.

.

1.1*5

asoid

a743

Time during which the

Temperature Remained Constant

Deg.C.

Pladnum.

i(

86Oo-86O

880°-890

Porcelain.

((

it

(C

((

10 min. 10 " 15 " 40 3 hours.

5 min.

5

5 " 1 hr. 20 min. 40 min.

Loss

in

Weight.

30 min. 1 hr. 20 min.

Grm. N0I068 trace.

;o.oo9

Percent- age Loss.

Remarks.

Per Cent.

No ailver.

(C

Much silver.

Globules of silver.

Globules of silver.

After maintaining the silver sulphate in the platinum vessel at temperatures of 825° C, 860° C. and 850° C, respectively, for periods of time amounting in all to one hour and five min- utes, the total loss in weight was less than 0.6 per cent, and no metallic silver could be found. After fifteen minutes at 900° C. the loss amounted to more than double that which had oc- vrurred during the whole hour at the lower temperatures, and metallic silver was to be seen around the vessel. After three hours at 880°-890° 0. the loss had reached nearly 12 per cent,

The Reactions Of The Ziervogel Process

showing 40 per cent, of the sulphate to be decomposed. The loss in weight by continuous heating could be detected at any temperature above its melting-point (655° C). Below 860°— 870° C. this loss was extremely small, and no metallic silver appeared even after an hour's time, so that the loss seemed to be due to the evaporation of the molten sulphate as such rather than to the dissociation of the salt At temperatures of 860°— 870° C, and above, the loss in weight was much more rapid, and the deposition of metallic silver indicated the decom- position of the silver sulphate. But not until 1095° C. was reached was there any agitation of the liquid due to the forma- tion of bubbles of gas throughout the substance.

In roasting argentiferous copper mattes the silver sulphate formed is associated with the oxides of iron and copper. To de- termine whether these oxides have any effect on the dissociation of the sulphate of silver, the sulphate was heated with (1) cupric oxide, (2) silica, and (3) ferric oxide. The reduction of metal- lic silver was found to be much more rapid when either of these oxides was present, as shown in Tables VI., Vii. and Viil. In each case the reduction commenced at the same tempera- ture, and this temperature corresponded with that at which the dissociation began when the sulphate was heated alone, viz., 860°-870° C. When heated to 870°-890° C. for three hours with four times its weight of cupric oxide, the sulphate was all reduced ; while the sulphate alone, for an equal time, at the same temperature, showed a loss of only 10 per cent., corresponding to a decomposition of but J of the sulphate present. When heated with either silica or ferric oxide, the decomposition above 860°-870° C. was fully as rapid as with cupric oxide. (See Tables VH. and Vm.)

Table VI. — Results of Heating Sulphate of Silver and CuO.

Quantltyof SubBtances.

Kind of Cnicible.

Temp, to

which Sutetance

was Heated.

Time during which the

Temp. Remained Constant.

in Weight.

Percentage Loss.

Remarks.

Gramme. /Ag-SO 0.3285

CuO 0.8155

(( (t ti

Porcelain. it

tt

I>eg.C.

5 min.

Grm.

875 1 5 " 0.009 875 i 15 " jO.018 870 ! 56 " 0.0625

Ihr. 20 m.

AllAg,

Decomposed.

And Their Temperature-Limits.

Table Vii, — Sulphate of Silver and Silica.

Quantity of Substances.

Temp, to Time during' Kind of which I which the i Loss Crucible. Substance Temp. I in

was , Remained Weight.

Heated. I Ck)n8tant.

I Gramme. ,

Deg.C.

870-900 .

30 min.

6 "

6 "

5 "

2 "

Orm.

None.

None. None. None.

Remarks.

Much metallic silver. Much metallic silver.

Table VJJLL. — Sulphate of Silver and Ferric Oxide.

Quantit J- of Substances.

Kind of Crucible.

I Temp, to Time during! I which I which the jSubstance; Temp, was Remained Heated, i Constant.

Gramme.

Deg.C.

10 min.

10 min. 1 hr. 30 m.

Remarks.

No silver.

Some metallic silver. Much silver.

Cuprous Oxide.

If cuprous oxide (CuaO) is added to a solution of silver sul- phate in water, metallic silver is reduced and appears as spangles according to the following equation : AgSO + Cu,0 CuO + CuSO, + 2Ag* (called the spangle reac- tion). Since silver sulphate is in the molten condition above 655® C, it was thought that the presence of cuprous oxide in the roast might cause a reduction of silver from the molten sulphate. It was impossible to ascertain by the loss-of-weight method just when the sulphate of silver began to decompose on being heated with cuprous oxide, as some of the lower oxide of copper became oxidized to the higher oxide by the oxygen of the atmosphere, with a corresponding in- crease in weight. This increase could have more than oftsct the loss due to the reduction of the sulphate of silver. It was therefore necessary to adopt some other method of ascertaining just when this change commenced, providing it did occur.

Balling, MetaUurgwehe Chemie, p. 58. Plattner, Orillae.

The Reactions Of The Ziervooel Process

After each heating, some of the mixture was removed from the crucible and examined with a microscope for particles of metal- lic silver. No indication of the metal could be found until the temperature rose to the point at which the change began with the sulphate alone, or with the sulphate in the presence of the other oxides, viz., 860°-870° C. Tabulated results of these heatings are given in Table IX.

Table IX. — Sulphate of Silver with Cuprous Oxide.

Quantity of Substances.

Kind of Crucible.

Gramme. {titi' Porcelain.

Temp, to whicli

Substance

was

Heated.

~Deg. C.

Time during! which the

Temp. Remained Constant.

((

ti

5 min.

Increase

in Weight.

Grm.

Loss

Remarks.

No metallic silver.

Metallic silver appears Much metallic silver.

Owing to the reduction above described, there must be no cuprous oxide in the roasted matte when ready for leaching. During the earlier stages of the roast, while considerable sul- phur in the sulphide condition is present, more or less of the cupric oxide is reduced to the cuprous state through the reduc- ing action of these sulphides. This lower oxide must be reoxi- dized by continuing the roasting operation with excess of air before leaching is begun. It is also known that cupric oxide is reduced to cuprous oxide by heat alone* at a high temperature. To determine at what temperature this reduction to cuprous oxide occurs, a series of experiments were carried out.

A quantity of crystallized copper sulphate was dehydrated, and then heated to a temperature ot 840° C. until the whole was decomposed to black oxide, as indicated by its color and by the loss in weight. A weighed portion of this cupric oxide was heated in a porcelain crucible in the electric furnace. The couple of the pyrometer was placed in direct contact with the

Favre and Maumen, Oomptes Bendusy 18, 658. Bendusj 99, 583.

Debray and Joannis, OompUs

And Their Temper Atu Re-Limits. 71

black powder. The heating current of 36 amperes was turned on, and the temperature rose rapidly. Readings of time and deflections of the galvanometer were recorded after the tem- perature rose above 840° C. The mirror of the galvanometer moved regularly up to 1050° C, where a slight retardation was detected. The change in rate of movement of the galvanom- eter mirror was very slight, but repeated experiments seemed to indicate some change at this temperature. To determine whether this was the temperature at which dissociation of cu- pric oxide into cuprous oxide and oxygen commenced, the gravi- metric method was employed. Three hundred and thirty- eight milligrammes of cupric oxide were heated to 900° C, then cooled and weighed. The analytical balance revealed no loss in weight. Again to 945° C, 1000° C. and 1045° C. respec- tively, with the same results. The heated oxide was cooled slowly in the furnace in some instances, and in others rapidly in open air. No loss in weight could be obtained up to 1045° C. After heating to a temperature slightly above 1050° C, the highest point being 1065° C, a loss in weight of IJ per cent indicated a partial change to have taken place. The loss was increased to 4.5 per cent, by heating again to the same temperature for ten minutes. The Royal Meissen crucible gave most uniform results. With some other makes of crucible the oxide of copper seemed to react with the crucible at tempera- tares below 1060° C, occasioning at times a loss in weight. The experiments were repeated a number of times with a plat- inum dish in place of the porcelain one. Some results with the platinum dish are as follows : 611 milligrammes of cupric oxide were heated to 1000° C. for fifty minutes, and cooled rap- idly out of the furnace. No change in color nor loss in weight. Again to 1035°-1045° C. for three hours, with like results. No change could be effected up to 1045° C. After heating again to 1050°-1060° C, a loss in weight indicated a partial reduction to the lower oxide.

Fusion of the Reduced Oxide. — The reduction was found to proceed slowly at temperatures but slightly above that at which it began. If the temperature were raised much above 1050° C. not only a reduction but fusion occurred. When the sub- stance was heated rapidly, so that time was not given for re-

72 The Reactions Of The Zibrvogel Process

duction to become complete, a temperature as high as 1150° C was obtained without fusion. If time were allowed for com- plete reduction to take place but slightly above 1050° C, the reduced mass fused at a temperature of 1065° C. This fused oxide solidified at a temperature near 1050°, the temperature at which reduction begins. This melting-point and freezing- point of the reduced oxide were found to remain constant, as revealed by the retardation of the pyrometer ; but if time were not given for complete reduction to be effected before fusion occurred, a mixture of the cupric and cuprous oxides, with a higher melting-point, would result.

In every case, after this reduction to the lower oxide, the upper portion of the mass was again oxidized to cupric oxide when cooled in air. From this action the question was sug- gested : Did the reduction begin at a lower temperature than that indicated by the above experiments, and escape detection by the balance because of reoxidation ? Fresh portions of the higher oxide were heated to and held at temperatures ranging from 800° C. to 1100° C, and cooled in an atmosphere of nitrogen.

Methods of Preparing and Using Nitrogen.

The nitrogen gas was prepared by passing air through heated ammonia-water and then over heated shot-copper con- tained in a glass combustion-tube. This tube was two feet long, and was kept red-hot by an ordinary combustion-furnace. From the tube the gas was conducted through two wash-bot- tles, one containing sulphuric acid and the other an alkaline solution of pyrogallic acid, and then into a gas-tank. After the copper in the tube was heated to redness, the apparatus was connected up and the current of air and ammonia passed through. The necessary suction was produced to draw the gases through the apparatus by operating a siphon from the inner side tube of the gas-tank. Oxidation began at the inlet end of the tube, and a portion of the copper-shot was coated with red oxide. The oxide of copper reacted on the ammonia, extracting its hydrogen and setting nitrogen free, the cuprous oxide being reduced by the reaction to metallic copper.

2NH. + 3Cu,0 N, + 3H,0 + 8Cu,.

And Their Temperature-Limits. 73

This reducing action of the ammonia gave fresh surfaces of metallic copper for extracting the oxygen from the current of air. The excess of ammonia and the water formed in the process were collected by the sulphuric acid in the first wash- bottle. The alkaline solution of pyrogallic acid was provided to take up any oxygen which the metallic copper did not ex- tract The nitrogen collected came partly from the air and partly from the ammonia.

It was found to be necessary to operate slowly, in order that the reaction in the tube should be complete. As a ftirther pre- caution, the tank of nitrogen collected was again passed through the tube of heated copper and through fresh solutions, to make sore that every trace of oxygen was removed. No trace of either oxygen or ammonia could be detected in the nitrogen from this second tank.

All the openings and joints of the electric furnace were luted with fire-clay except the annular space around the porcelain tube which carried the couple through the cap, after the cruci- ble with the cupric oxide had been placed in position. The oxide was heated to the desired temperature and held there for ?ome minutes ; then the porcelain tube and couple were re- moved, and a similar tube, open at both ends, was placed in the opening through the cap, the lower end of the tube coming next to the heated oxide. This tube was connected with the gas-tank (nitrogen had been passed through the rubber tubing and porcelain tube to remove the air from them) and the nitro- gen was turned on. The heating-current was cut off and the famace and contents allowed to cool. In this way the cooling oxide was continuously surrounded by an atmosphere of ni- trogen.

A brief description of these tests, and the results of the &aine,are here given: 1.735 grammes of cupric oxide were heated to 950 C. for fifteen minutes, then cooled in an atmosphere of nitrogen as above described. The analytical balance revealed DO loss in weight, and the color remained black. No change had occurred at this temperature. Another sample was heated to 1035° C. for ten minutes, and cooled in nitrogen. No change in color and no loss in weight could be detected. On heating the same again to 1065° for ten minutes, and cooling in a similar manner, the color had changed to reddish brown.

74 The Reactions Of The Zibrvogel Process

and the balance revealed a loss in weight of 8 per cent. After heating for twenty minutes to the same temperature, and cool- ing in nitrogen again, the loss was found to be increased to 9 per cent., out of a possible 10 per cent., which is the calculated loss for a complete change of cupric into cuprous oxide.*

These results confirmed those without the nitrogen, except that the reductions as shown by the balance for temperatures above 1050° C. were greater for corresponding lengths of time. This was due to the absence of reoxidation in the atmos- phere of nitrogen. No reduction to the lower oxide was found for temperatures below 1050° C.

The dissociation of the higher oxide of copper into the lower oxide was found by the above-described experiments to occur at 1050° C, a temperature nearly 50 degrees below that at which the rapid reduction of silver sulphate begins, but nearly 200 degrees above that temperature at which silver sulphate commences to decompose slowly when alone, and more rapidly in the presence of the oxides of copper and iron. This reduc- tion of cupric to cuprous oxide by heat alone is, therefore, not of importance in the Ziervogel process, as it is eflfected only at a temperature two hundred degrees above that at which the roasting mass can safely be heated, because of other reactions.

Magnetic Oxide of Iron,

Magnetic oxide of iron reduces metallic silver from a solution of silver sulphatef according to the following equation : 4Fe80 + AgSO, 6Fe,0, + SO, + 2 Ag. This reaction is much less rapid than that of the reduction of the metal by cuprous oxide. The reaction is so slow that the presence of small quantities of the magnetic oxide in the roasted matte is not fatal to the leach- ing process, as is shown by the following experiment: 50 milligrammes of silver sulphate were placed in each of two small beakers and dissolved in hot water. To one was added one gramme of finely powdered magnetic oxide of iron. The oxide employed was magnetite from Port Henry, N. Y. The solution, with the powdered magnetite, was heated for ten minutes near the boiling-point of water. This solution was

2CuO Cu,0 + 0

(160)= (144) (16). t Plattner, Qrillage, p. 141, par. 3. Balling, MeicJlurgische ChemUf p. 57.

And Their Temperature-Limits. 75

then filtered and washed, and both the solutions of sulphate were titrated with ammonium-sulpho-cyanate. The results of the titration showed 7.6 e.c. for the solution which had been treated with the magnetic oxide, and 7.8 c.c. for the other 3olu- tion. The loss due to the magnetic oxide was only 2.56 per cent.

When ferric oxide (FejOj) is subjected to a high temperature it is reduced to magnetic oxide (FeO). To determine at what temperature this reduction occurred, providing it came within the limits of temperature allowable in the Ziervogel process, a series of experiments were carried out in a manner similar to those described for cupric oxide. It was found that no reduc- tion to magnetic oxide was effected until a temperature above 1100** C. was reached. The exact temperature at which dis- gociation commenced was not definitely determined. The tests, however, showed that the change of ferric to magnetic oxide by heat alone, coming at so high a temperature, was not of importance in the roasting process.

Oxidation of the Sulphides. The temperature at which the sulphide begins to oxidize in a current of air was not determined for each individual sul- phide. It was found on roasting copper mattes in the oven- furnace that, owing to the large amount of sulphur in them, as soon as rapid oxidation commenced, the temperature rose rap- idly to 450° to 500° C. Since an excess of air is desirable to get the oxidation to the sulphate* instead of the formation of SO, and the oxides of copper, this rapid rise in temperature cannot be readily prevented. The principal part of the oxida- tions occurs above 450° C.f The exact temperature at which oxidation commences is of little consequence in the process.

Roasting of Argentiferous Copper Mattes. The operation of roasting the argentiferous mattes was car- ried on in the gas oven-furnace described and illustrated in Fig. 3. Temperatures up to 900° C. could be readily obtained in the furnace, and by regulating the gas and blast, the heat

"The Metallurgy of Argentiferous Copper Compounds.** H. M. Howe.. Pndudum Oold and Silver in the U, S,, Burchard, Washington, 1883, p. 757. t Steinbeck, Chan.'Analy. Untersuchungen, p. 49.

76 The Rbactions Of The Ziervogel Process

was easily kept under control. Cast-iron trays were employed to receive the matte, and these were placed directly upon the fire-brick hearth. The trays were 20 in. long and 5 in. wide by |-in. deep, inside dimensions; and the sides and bottom were of uniform thickness of f-in. Rakes and rabbles of such size as could be worked through the two port-holes in the fur- nace-door were used to stir the roasting charge. An iron spoon attached to the end of a f " rod, and small enough to be inserted into the port-holes, served for taking samples at the various stages of the roast.

The platinum and platinum-rhodium wires of the pyrometer were strung through a doubly-perforated fire-clay tube, |-in. external diameter. At the end of this long tube, next the junction of the wires, was arranged a short length of doubly- perforated tube of somewhat smaller diameter. By means of this short length, the junction of the couple could be readily raised and lowered, in the material whose temperature was sought, without disturbing the longer tube. When the fiirnace- door was open, the tubes were passed into the furnace through the open door. If it was necessary to close the door, the tubes were run in through one of the port-holes. The water-bottle containing the cold junctions of the pyrometer was placed on a stand near the fiirnace-door. The thermo-electric couple was kept within the furnace during the entire time the matte was roasting.

A number of mattes with varying amounts of iron, copper, and silver, were treated, and the samples taken at the different stages of the process analyzed. The matte with which most of the experimental work was done had the composition given in Table X. It was obtained from the Orford Copper Works at Bergen Point, N. J., and its silver content enriched to 100 oz. per ton.

Table X. — Composition of the Argentiferous Matte.

Per cent.

Copper, 60.80

Iron, 22.64

Sulphur, . . . . . .26.80

Silver, 0.31 (100 oz. to ton)

Lead, trace.

Gold, trace.

Arsenic, trace.

Antimony, trace.

And Their Temperature-Limits. 77

This was ground fine enough to pass through a GO-mesh screen, and pounds of the finely-ground material placed in the east-iron tray, and the tray introduced into the oven-fur- nace. The furnace was lighted, and the gas and blast so regu- lated as to cause the temperature to rise slowly. After the eipiration of one hour, the temperature had reached 325° C. At this stage the sulphur of the matte began to burn off, and owing to the heat of this combustion the temperature rose rapidly. In fifteen minutes the degree of heat of the charge ranged from 470° C. underneath to 535° at the surface where the oxygen of the air supported the combustion of the sulphur. Continuous stirring was required at this stage to prevent frit- ting or caking of the particles of the upper layer of the charge. As the matte -was stirred, the temperature rose slowly, and at the end of the second hour the material was uniformly heated throughout to C. Until now, the upper portions had been hotter than those below. By this time the major part of the sulphur had heen oxidized, and the heat from this source began to decline, so that from this time on the temperature of the upper layer was less than that underneath. At the end of another half-hour the temperature had fallen considerably, and was brought up again only by turning on more gas and blast. The door of the furnace was closed a little later. The highest temperature attained during the four hours the matte was roasting was 750, and this was attained only at the bottom layer of the matte next the pan, just before the gas was turned off.

The operation was stopped at this stage while the matte had the composition shown in sample 'No. 7 of Table XI., and continued next day. About J of the partially roasted matte was taken in a roasting-dish of Denver fire-clay and heated in a gas muffle-furnace. The furnace was heated to 720° C, and the dish and contents introduced. The mouth of the muffle was closed by a fire-clay door. In half an hour the tempera- ture had risen to 750° C, and considerable sulphate still re- mained, as shown by sample No. 9. On removing the door and adjusting the flame so that the muffle did not cool down, a draught was established in the muffle, and heavy fumes of snJphuric anhydride appeared at the top of the flue, indicating a rapid dissociation of the copper sulphate in the furnace. At

78 The Reactions Of The Zibrvogel Process

the end of 45 minutes every trace of neutral sulphate of cop- per had disappeared. (See sample No. 10.) There was seen to be a great increase in the rate of dissociation at any tempera- ture with a strong draught through the muflBle, over that with closed muffle. This corresponds to the phenomenon observed in connection with the dissociation experiments in the electric furnace. After all the sulphates of copper had been decom- posed, the charge was heated to 850*, to determine whether any material loss in silver sulphate occurred below the tem- perature to which it was found to be safe to heat the pure sulphate of silver in the experiments with the electric furnace. Samples were taken at intervals of 15 to 30 minutes, and these were put into convenient receptacles, labeled, and set aside for analysis.

Methods of Analysis.

Soluble Sulphates of Iron and Copper.

Each sample was analyzed for (1) sulphates of iron and cop- per which were soluble in water, (2) insoluble or basic sulphates, (3) silver sulphate, and (4) total copper. Total silver was deter- mined in a few cases. To ascertain the amount of iron and copper sulphates soluble in boiling water, two grammes of the sample were weighed out on the analytical balance and added to 150 c.c. distilled water in a No. 3 lipped beaker. The eon- tents of the beaker were heated on an iron plate to boiling and allowed to remain at that temperature for a few minutes. The solution was filtered into a No. 4 beaker and the residue washed by decantation several times with boiling water, which water served for washing the filter. To the clear solution was added a piece of sheet aluminum, 2'' x 2" x and a few drops of sulphuric acid. The solution was boiled again on the hot plate until all the copper was precipitated and the ferric iron reduced to the ferrous condition. The color-test with ammonium- sulpho-cyanate served to indicate when no ferric salt remained. The solution was decanted through a filter and the precipitated copper washed thoroughly by decantation with hot water, the wash-water being passed through the filter to prevent the loss of any particles of copper poured off. The filtrate was titrated for iron with a standardized solution of potassium perman- ganate.

And Their Tbhpbratube-Limits.

The copper in the beaker and on the aluminum plate was dissolved in dilute nitric acid. A few drops of the dilute acid were poured onto the particles of copper on the filter and allowed to pass into the vessel containing the dissolved copper, and the filter was thoroughly washed with distilled water. Ammonia was added in excess, and the blue solution titrated with a standardized potassium cyanide solution. The results of these analyses, given in percentage of the two grammes em- ployed, are shown in columns 4 and 6 in Table XI.

Table XI.—

5a of

:f&mple

;

Time.

After 75 min.

120 "

140 "

235 "

245 "

265 "

310 "

320 "

;

340 "

Direct Results of Analysis of Samples.

Tempera- ture.

Deg.C.

Cuas

Feaa I FeSO*.

Per cent. Per cent.

585-d95

None.

trace. None.

Basic Sulphates.

Per cent

None. JB.534 None. None.

Silver.

Oz.perT. - i Per cent. I of Total I Silver.

The residues from all the samples except the last two, after treatment with boiling water, were of a decided green tinge, owing to the presence of particles of hydrated basic sulphate of copper,* which is of a green color. Portions of the resi- daes were heated in a porcelain crucible in the electric furnace, and after dehydration the basic salts were found to com- mence to decompose by heat alone at 700° C. This tempera- ture corresponds with that at which the basic sulphate CuO,CuSO decomposes.

To determine the amount of basic sulphates present, the method used by Steinbeckf was employed. To the residue from the two grammes taken for the previous analyses was added three times its weight of sodium bicarbonate (NallCOj)

Wattif9 Dietumary of Chemigtry, Muir & Morley (1894). Also Boscoe & Sch., ToL iL, pL i , p. 339. t Chemisehe-ATialytiache TJnUrmchungen etc

80 The Reactions Of The Zieryooel Process

and enough water to dissolve most of the soda. This was allowed to stand for twenty-four hours with occasional shaking. The solution was filtered and the residue washed by decanta- tion and finally on the filter, to remove every trace of dissolved sulphate. This solution was acidified with hydrocljloric acid and the carbon dioxide removed by boiling. Barium chloride was added in slight excess, and the whole was boiled a few minutes and set aside for twelve to twenty hours. The barium sulphate was determined gravimetrically, and from this the percentage of SO from the basic sulphate in the sample calcu- lated. Table XI. gives, in percentage of the two grammes of sample originally taken, the SO obtained by this method. The method is similar to the one given by Fresenius for the deter- mination of lead sulphate. It was adapted by Steinbeck to ascertaining basic sulphates in samples from roasting matte. By careful tests he found that the sodium bicarbonate reacted with all the sulphate present, and had no efiect on the sulphides.

Analysis for Silver Sulphate.

For silver sulphate determinations, 0.2 assay ton from each sample was taken and treated with hot water in a similar man- ner to that employed for the other soluble sulphates. If the cop- per in the solution amounted to more than 1 to 2 per cent, of the quantity of matte taken, the following method was employed To the solution of sulphates was added sodium chloride of about " normal " strength, to precipitate the silver as chloride. Lead acetate and sulphuric acid were added to form a heavy precipi- tate to carry down the silver chloride. The whole was allowed to stand for six to twelve hours, when the clear liquid was de- canted through a filter, and finally the precipitate was removed to the same filter. The precipitate was scorified and cupelled for silver.

If the amount of copper present was less than 1 per cent, the silver in the hot>-water solution was determined by titration with standardized ammonium-sulpho-cyanate solution according to " Volhard's method."t

The silver insoluble in hot water was ascertained by treating

Manual of Practical Aaaaying, Funnan, pp. 250-251.

t Liebig's Ann d, ,, cxc, 1. Sutton, Volumdric Analysis 8th ed., p. 155.

And Tieir Tbmpbraturk-Limits. 81

the tidne from the solution containing the silver sulphate with strong nitric acid and allowing the solution to stand on the hot plate until the red fumes were driven oft' The silver wag deterniined by the combination method given by Furman.* The silver obtained from the residue was added to that from the hot-water Bolution, to give the total silver in any sample. In Table XI. the silver-content is given in ounces per ton, and since the original matte contained 100 oz. to the ton the figures in column headed "Silver" represent also the percentage of total silver.

Reducing Factors.

The data in Table XI. are not in a condition for direct com- parison of the quantities of the sulphates at the various steps in the process. During the roasting operation much oxygen of the air was taken up in the formation of sulphates without a corresponding loss in sulphur. The weight of the charge in- creased as the sulphates continued to rise in amount, and decreased as these compounds were decomposed. The volume also increased and diminished, as was readily seen within the tray in the furnace. In analyzing the samples taken at succes- sive stages in the process, the same weight of each sample was taken. Because of the rapidly changing weight of the roast- ing-charge, the amount of copper-, or iron-, or silver-sulphate in these equal weights of samples did not represent the relative amounts of these compounds in the charge at these stages in the process. To enable one to compare the analytical data in Table XI., it was necessary to ascertain quantitatively the change in weight of the roasting-charge.

Tlie total amount of copper in the charge did not change during the operation. The amount determined in equal weights of the respective samples varied through considerable limits. From these varying percentages of copper present in the differ- ent samples the change in weight of the charge was ascertained. For a decrease in the percentage of copper an increase in the weight of the charge must have taken place, and for an increase in copper-content of a sample a diminution in the weight of the charge. In other words, the relative weights of the charge

Manual of Pr€Lctieal Assaying. VOL. ZXXIII. — 6

The Reactions Of The Zibbvogbl Process

at different stages are in inverse ratio to the copper-content of equal weights of samples taken at these stages. Table XTT. gives the percentage of copper present in each sample taken. Sample 7 shows the lowest percentage of copper. At the time this sample was taken, the weight of the charge was a maxi- mum. Reference to Table XI. shows the maximum total sul- phates in sample 7.

Putting the weight of the original matte, before roasting commenced, as unity, we obtain the weight at any step in the operation, as follows :

1 : X : : 89.00 (per cent. Cu in sample 7) : 50.8 (per cent. Cu in

original matte).

X 1.303, which is the ratio of the weight of the charge at the time sample 7 was taken to the weight before roasting commenced. Table XTT. gives such a ratio or reducing factor " for each sample.

Table XII. — Total Copper and Reducing Factor

No. of Sample.

Total Copper.

Inverse Ratio or Reducing Factor.

Per cent.

Original Matte.

By the aid of these " reducing factors " the data of Table XI. may be brought into a condition for direct comparison. By multiplying the percentages of the different sulphates in each sample, as obtained by analysis, by the reducing factor for that sample, one obtains percentages which represent the rela- tive amounts of these sulphates in the entire charge at the time the sample was taken. A table of corrected results may thus be obtained.

and thbir temperature-limits. 83

Total Copper. One gramme of each sample was treated with 7 c.c. nitric acid and 5 c.c. sulphuric acid in a flat-bottomed flask of 400 c.c. capacity. This was heated until the nitric acid was expelled and the sulphuric acid was boiling freely, then cooled and di- lated with 50 c.c. distilled water. Ammonia was added in excess, and the solution transferred to a 500 c.c. flask, and fur- ther diluted to exactly 500 c.c. The flask and contents were allowed to stand until the precipitate of hydroxide of iron had subsided. The time required was from two to five minutes. By means of a pipette, an aliquot part of the blue solution, free from the brown precipitate, was taken out and titrated for cop- per with standardized potassium cyanide. This method was much shorter than the one ordinarily employed, wherein the copper is removed from the solution containing the iron and copper salts by means of metallic zinc or aluminum. The re- sults from the two methods were found to check very closely. Comparative results on the hot-water solution of some of the samples are given below :

Table XLIl. — Soluble Copper Sulphate.

Sunple, No. 6.

Perct.

Aliquot part method, 11.7

Alaminnm precipitation, . . . . 11.8

Discussion of Results of Analyses. Sulphate of Iron. Table XlV. gives the corrected results of analyses of twelve samples, taken at as many different stages of the process. At a temperature of about 850° C. the sulphur of the sulphides bgan to bum off, and the temperature rose rapidly until it rtched a point near that at which the sulphate of iron is decom- posed. The tendency to the formation of this sulphate would not '>e strong at a point so near the dissociation temperature. The small amount of the sulphate of iron shown in the table may W explained by this fact. The maximum amount of sulphate of iron present would not be sufficient to assist very materially in forming copper sulphate by the evolution of its sulphuric arihydride daring dissociation, though it is stated in all the text-books that consider the Ziervogel process, that the copper

No. 7.

No. 8.

No. 10.

Perct

Per ct.

Per ct.

The Reactions Of The Ziervogel Process

Table XIV.—

Corrected Results of Analyses of Samples.

No. of Sumple.

Time.

Tempera- ture.

Cu as I Fe as CUSO4. FeS04.

Basic Sulphates.

SDver. '

After 76 min. 106 " " 120 " " 140 " 190 " " 265 " 310 " 320

Deg. C. 565-70

Percent. 1 4.858 I 0.404 8.803 ' 0.67 10.413 0.71 12.071 0.49 13.890 0.49 14./)34 0.32 11.774 None.

Per cent. 8O4. None.

None.

Or. per T. Per cent, of Total Silver.

trace.

4.526 !

None. 1

None.

None. '

sulphate is formed through the action of the sulphuric anhy- dride evolved from the decomposing sulphate of iron. To fur- ther ascertain if the iron sulphate played any particular roU. in the formation of copper sulphate, a matte containing no iron was prepared and roasted in the manner described above. The rapid accumulation of copper sulphate at temperatures corresponding to those at which this compound appeared in the iron-copper matte showed that the iron sulphate was not es- sential to the operation of sulphatizing the copper compounds. The rise in the sulphate of copper is a gradual one, and is not dependent on the action of the gaseous products of the disso- ciation of the sulphate of iron.

The maximum amount of soluble iron sulphate was obtained in sample 3, taken at a temperature of 570°, immediately below that at which ferrous sulphate begins to decompose (viz., 590° C). This iron sulphate decreased from this time until, at a temperature of 700° C, only a trace remained.

Soluble Sulphate of Copper.

The soluble sulphate of copper reached its maximum at a temperature — measured with the contact of the couple below the upper layer — slightly above that at which its dissociation begins. The surface of the roast at this stage (sample 6) was cooler than the layers underneath the surface ; and, while the dissociation had begun below the surface, because of its high temperature, the upper layer, where the sulphate really formed, had not reached the decomposing point, and was supplying the

And Their Temperature-Limits. 85

material that was dissociating underneath. At temperatures near 656° C. — that at which the neutral sulphate begins to decompose — the change in amount of neutral sulphate was not rapid.

After sample 6 was taken the operation was carried on with the furnace-door closed, in order to keep the temperature as uniform aa possible, and the gaseous products of dissociation were not readily removed. The result was that the dissocia- tion was slow, though it was continuous, and at a temperature of 750® to 760° (sample 9) about 4 per cent, of the soluble sul- phate remained. Fifteen minutes afler sample 9 was taken, when the door of the muffle-furnace was opened and a strong draught established, the rate of dissociation was greatly in- creased. Inside of thirty minutes after the door was opened no soluble copper sulphate remained, as shown by sample 10.

Basic Copper Sulphate.

The basic copper sulphate results not alone from the decom- position of the neutral sulphate, but also from the action of the sulphides and sulphur dioxide on the sulphatizing roast* It appeared as a trace in sample 2, and increased in amount from that time until it reached a maximum in sample 7. The tem- perature at the time sample 7 was taken was somewhat above that at which the basic salt (CuO,CuS04) begins to dissociate. The fact that the surface was cooler than the temperature in- dicated by the pyrometer may account for this apparent dis- crepancy ; but, as has been shown on page 63, if the neutral sulphate present is decomposing with the evolution of sulphuric anhydride, the dissociation of the basic salt, may not begin until a temperature a few degrees above 700° C. is reached. The results in the oven- and muffle-furnaces with the roasting matte confirm those obtained in the electric furnace. The diminu- tion in amount of basic sulphate is continuous from the time of taldng sample 7. Rapid action is shown by the table to have occurred when the furnace-door was opened — between the sam- ples 9 and 10.

Sulphate of Silver.

'So sulphate of silver was found in samples 1, 2, and 3, and but a faint trace in 4. From that time on, the amount increased

Steinbeck, CkenL-AnaL, etc,, p. 54.

86 The Reactions Of The Ziervogel Process

until sample 11 was taken, at a temperature slightly above 750°, when the maximum was shown. No trace, of either neu- tral or basic sulphate of copper remained in sample 11. The roasted matte was finally heated to 850° C, to determine whether the temperature could be safely raised to that point, as was shown to be true in the electric furnace. In this par- ticular roast there was no necessity for proceeding beyond the time of sample 11, since, at that time, there remained no sul- phates of copper to decompose. The loss due to the excessive heat was small, as seen by comparing the silver in samples 11 and 12.

The whole time occupied in the operation was 5 hours and 40 minutes : One hour in heating the furnace and matte to 350°, two hours and twenty minutes in forming sulphates, two hours in decomposing the sulphates of copper, and twenty min- utes in heating to 850° C. after all the copper sulphates had disappeared.

Results of Roast No. 2.

Another roast of one and a half pounds of the same matte was carried through, and the entire operation effected in the oven-furnace. The temperature was raised more rapidly than in the former case, and the time during which the roasting pro- ceeded was but three hours and ten minutes, a little more than half the time occupied in the previous operation. The roasting was completed in one operation. Two hours were taken to form sulphates, and these corresponded in amount to the simi- lar compounds formed in the previous roast. Less than one hour was required to decompose the copper sulphates, the tem- perature during the dissociation period being much higher than it was during the same period in the former operation. Care was taken, however, not to heat the matte above 850° G. After all the copper sulphates had disappeared the charge was heated above 850° C. for fifteen minutes, the highest point reached being 910° C. The maximum silver sulphate occurred in sample 11 at 835°-845° C. This decreased rapidly after 850°-860° C. was attained; and in sample 13, taken at 910° C, the soluble silver compound amounted to less than one-half of that soluble at 845° C. in sample 11. Table XV. gives the direct results of the analyses of samples from this roast. Total copper and the reducing factors are shown in Table XVI., and the corrected results of analyses in Table XVII.

And Thbir Temperature-Limits. 87

Table XV. — Direct Results of Analyses of Samples.

Xo.of . Sample.'

Time.

Tempera- ture,

Deg.C.

Per cent.

After 30 min.

11 .*2

n.7

None.

None.

Cuas C0SO4.

Feaa

Basic

Silver.

FeSO*.

Sulphates.

Oz. per Ton.

Per cent.

Per cent. 9O4.

trace.

trace.

trace.

n.68

None.

trace.

None.

Table XVI. — Total Copper and Beducing Factors.

Na of Sample.

Total Copper.

Reducing Factor.

Per cent.

Original Matte.

Table XVH. — Corrected Results of Analyses of Samples.

Time.

Is

After 30

znin.

" 45

It

" 80

€t

" 90

" 100

ti

" 130

It

" 140

tt

" 150

" 160

it

ft

€€

190

it

Tempera- ture.

Cuas CU8O4.

Per cent.

None. None.

Feas FeSOi.

Per cent. trace.

Basic

Sulphates.

Per cent.

trace.

None.

Silver 02. per Ton Perct.

trace.

88 The Reactions Of The Zibrvogel Process

Basic Sulphate of Copper.

The basic sulphate of copper is practically insoluble in dis- tilled water, hot or cold ; but in water containing neutral cop- per sulphate in solution this basic salt is soluble to a considera- ble degree. This fact partly accounts for the maximum soluble sulphate coming at a temperature above that at which the neu- tral sulphate begins to decompose (viz., 653° C). The basic salt increases rapidly from the time the temperature of disso- ciation of the neutral salt is reached (sample 4); and the solu- tion of neutral sulphate, acting upon this increased quantity of basic sulphate, gives the maximum soluble sulphate at a stage when the actual amount of neutral salt in the roasting mass has passed its maximum. This explanation applies to the other roasts, whose analyses are given in this paper.

Roasting of Matte Free from Iron.

Copper sulphide was prepared by treating a solution of cop- per sulphate with hydrogen sulphide from a generator. The sulphide was collected and dried. To 175 grammes of this black sulphide was added a small quantity of silver sulphide, prepared by precipitation from a solution of silver nitrate. These sulphides were mixed and placed in a fire-clay crucible, and fused in a gas crucible furnace. The molten matte was poured into cold water contained in an earthen jar of 5 gallons capacity. The granulated mass was ground in a mortar to pass through a 60-mesh screen. The silver and copper contents were as follows : Copper, 74.8 per cent. ; silver, 235 oz. to the ton. One hundred grammes of this matte was placed in a fire- clay roasting-dish and heated in the muffle-furnace. The couple of the pyrometer was placed within the roasting-charge. Though but forty minutes was occupied in reaching the tem- perature of maximum copper sulphates, and no iron sulphate was present to assist in forming these compounds, still the amount formed, as shown in sample 1, was considerable. Table XVin. gives the corrected results of analyses of samples taken at successive stages in the process. The results of this roast on copper matte free from iron correspond with those of the iron-copper matte given in Tables XIV. and XVII.

In the operation of roasting the argentiferous copper mattes

And Their Temperaturb-Limits.

Table XVITT. — Corrected ResvUs of Analyses of Samples.

Time.

§.S I Total SS Copper.

' Reduc- , iDg Fac- "m tor. eg

Dejf. C. Per ct.

On ginal Malte 74.80

1 After 40 min. 675-685 65.13

750-760i 66.68

790-800 67.12

810-815 69.53

845-850 75.00

870-875 77.31

890-9001 77.30

Per cl. ofwh'le

Per ct. I Oa. per 8O4. Ton.

8.44 1 trace

trace

Ccs

Per ct.

6S

Oz. per Ton. I

it was found desirable to have an excess of air,* not only to facilitate the production of sulphates, but also for the removal of the gaseous products of their decomposition. The more rapid the dissociation, the less the time during which the roast- ing matte is held at a high temperature, and consequently the less the loss in silver. Above 655° C. the sulphate of silver is in the liquid state, and experiments seem to indicate a slow but continuous loss — possibly by volatilization as sulphate — after the substance is thoroughly fused, even though the temperature is not raised to the point at which it decomposes.

On the whole, the results of the roasting operation confirmed the facts determined with the electric furnace. To decompose the sulphates of copper, a temperature above 700° C. was re- quired. The rate of decomposition of the sulphates was more rapid as the temperature was raised above 700° C. ; but there was found to be no necessity for heating the charge above 800° C. to complete the process. Care needed to be taken not to allow the furnace in any part to become heated above 850° C.

By the aid of a reliable pyrometer, and with a range of 150° C. 270° F.) between the temperature at which the basic sulphate of copper begins to change to copper oxide and the temperature to which silver sulphate can be safely heated, the workman in charge of the furnace should be able to conduct the operation of roasting, in the Ziervogel process, without un- due loss of silver. Having in mind the facts set forth in this

"The Metallurgy of Argentiferous Copper Compounds," by H. M. Howe, in PndMdifm of OoldandSHver in the United States Burchard, 1883, p. 757.

90 Thb Reactions Of The Ziervogbl Process, Etc.

paper, the superintendent should be able to get good results in the Ziervogel process without the aid of expensive skilled labor in the management of the roasting-furnace.

Resulphatizing the Metallic Silver Resulting from the

Decomposition of the Silver Sulphate by

Excessive Heating.

The iron-copper matte of the composition, given on page 76 was roasted in the oven-furnace until all the sulphates of iron and copper were decomposed. The temperature was allowed to rise to 905° C, and, as a result, much of the silver sulphate was decomposed, with a corresponding precipitation of metallic silver. Analysis of the dead-roasted charge showed but 35.2 per cent, of the entire silver to be soluble as sulphate.

A portion of this roasted material was mixed with 5 per cent, of its weight of dehydrated ferrous sulphate, and heated in a roasting-dish in the muffle-furnace for fifteen minutes. The temperature was allowed to rise slowly above 590° C, and the highest point attained was 750° C.

0.6 A.T. of the material was weighed out, and the sulphate of silver dissolved by means of hot water, as already described. The solution was titrated for silver with ammoniam- sulpho-cyanate of such strength that 1 c.c. corresponded to 0.0047 g. of silver. 11.6 c.c. of the solution was required, showing 0.0545 grammes of silver, soluble as sulphate, in the 0.6 A.T. of the roasted matte, or 90.8 oz. per ton.

The percentage of soluble sulphate was thus increased from 35.2 to 90.8 by means of the ferrous sulphate added to the charge.

A second experiment was carried through with a quantity of the same dead-roasted matte, containing 35.2 oz. silver per ton, soluble in hot water. A relatively larger amount of ferrous sulphate was added to the charge, and the roasting occupied more time. The results of the titration with ammonium- sulpho-cyanate showed 93.8 oz. silver per ton, soluble in hot water.

Another sample of the 100-oz. matte which had been dead- roasted, but which had been heated only to a temperature of 880° C. and contained 64.4 oz. of silver soluble as sulphate, was heated in the same manner as described above. After the re-

The Auditing Of A Mining Company'S Accounts. 91

sulphatizing by the ferrous sulphate, the percentage of silver soluble as sulphate had been raised from 64.4 to 91.3.

From these experiments it is seen that the metallic silver, in the finely-divided condition in which it exists in the over- roasted matte, is readily resulphatized by the sulphuric anhy- dride evolved from the decomposing ferrous sulphate. No doubt other decomposable sulphates would accomplish similar results, providing their dissociation occurs at a sufficiently low temperature. The sulphates of sodium and potassium, as such, do not readily decompose by heat alone. Ferrous sulphate is a convenient compound to employ, not only because of its com- parative cheapness, but because it begins to decompose at a temperature far below that to which the sulphate of silver can be safely heated. Though it begins to decompose below 600° C, the decomposition is not rapid until 650° to 700° C. is at- tained. If the mixture of over-roasted matte and ferrous sul- phate be rapidly heated to a temperature near 700° C. — i.e. that at which the basic sulphate dissociates — there will be little cupric sulphate formed, but the sulphuric anhydride fumes will react directly upon the metallic silver. There will, therefore be no necessity for raising the temperature or prolonging the time in order to decompose the sulphates of copper, and thereby running the risk of again depositing the silver of the sulphate in the metallic state.

The Auditing of a Mining Company's Accounts.

BY CHARLES V. JENKINS, ROSSLAND, BRITISH COLUMBIA. (New York and Philadelphia Meeting, February and May 1902.)

The comprehensive audit of the accounts of a mining com pany is extremely important in its relations to the legal situation and obligations of the corporation, the personal liability of the directors, and the interests of the investing public. A consider- ation of the subject as affecting the professional duties and fixing the responsibility of a mining engineer engaged in the expert examination of a mine or in charge of mining opera- tions, is equally important, though this phase of the question is not often presented systematically.

92 The Auditing Of A Mining Company'S Accounts.

Business customs have pretty clearly established the purposes and principles of an audit. But in the absence of statutes compelling strict periodic investigation of their financial affairs, many companies of excellent repute do not avail themselves of the advantages afforded by such an audit. On the other hand, the failure of many companies to make public the true state of their affairs by means of an adequate financial audit is the frequent cause of loss to investors. The value to both parties of a systematic and thorough examination of company accounts is becoming, however, more and more generally appreciated ; and it is to be hoped that this may result in suitable legislation, requiring an annual audit of the accounts and financial affairs of all private corporations, and providing for the license and registration of competent, professional accountants. Such a rule would tend to eliminate that element of fraud and the consequent danger of loss to which the stockholder is exposed, when he is forced to rely upon officials for information relative to the standing of the company in which he is interested. True, a financial audit offers no protection against the false or erroneous statements of the condition of the mine itself. Nor will it assist stockholders in penetrating the mysterious reti- cence or paradoxical ambiguity with which boards of directors muzzle and muffle their reports regarding the present condition and future prospects of their mines — a policy of concealment and of mystification which operates, as positively as tangible fraud, to enhance the element of speculation present, in vary- ing degree, in all mining enterprises.

But it is safe to say that in a mining venture, where risk is always expected, capital will more readily seek investment, and stockholders will more cheerfully assume risk and more will- ingly support any reasonable policy of a board of directors, if good faith and frankness are shown by regular and comprehen- sive reports and audits.

The Value of an Audit.

The value of a commercial or general business audit depends upon its purpose, its minuteness of detail, the authority and responsibility of the auditor, and the scope of his instructions. The duties of an English chartered accountant, acting as an auditor, are defined, and, to a certain extent, specified by the

The Auditing Of A Mining Company'S Accounts. 98

" Companies Act " of 1862, which compels an annual audit of all registered joint-stock companies. The United States law has a similar provision, compelling the examination of all na- tional banks by qualified government examiners. But so far 86 other corporations of private enterprise are concerned, an auditor's duty consists in performing that for which he is era- ployed, and he is responsible to his employer only. If his ap- pointment depends upon the good will of the company's officials, the presumption is that he will act as their agent rather than as the agent of the stockholders ; or, if he be engaged to ex- amine accounts and report upon some particular question, it is not likely that he will take it upon himself to extend his ex- amination and report to cover more than that question. For instance, if he is asked to ascertain whether a reported reserve- fand is real, or exists upon paper only, and how the said fund is invested, or to say whether, in his opinion, the working- capital is sufficient, he would discharge his duty by a partial examination of the accounts and a report upon the one ques- tion submitted to him. But when a complete audit of the ac- counts of a mining company is required for the purpose of pre- senting to the stockholders a statement exhibiting the financial position of the company, and furnishing data which may pos- sibly assist in deciding upon future operations, the auditor, if employed as the agent of the stockholders, will exhaustively examine and check all books of account and all the financial affiiirs of the company.

Inspection op Accounts by Mining Engineers.

In examining a mining property for clients who contemplate purchase, the mining engineer often finds it necessary to make an exhaustive search through the accounts and records previously kept by the owners of the mine. This is, perhaps, most frequently the case when it is desired to ascertain the actual cost of mining at a prodacing mine. If such a mine has been operating suf- ficiently long to have established a fairly uniform cost, he may be warranted in accepting the figures given by the owners, supplemented by only a cursory inspection of the accounts. But in cases of doubt or suspicion it may be desirable to verify the figures given. While some mining companies, in calcu- lating the cost per ton of the ore extracted, include all expenses

94 The Auditing Of A Mining Company'S Accounts.

of dead-work, development, exploration, etc., many others state as the cost of extraction-work the actual expenditure for stoping and hoisting only, treating the developmentwork, especially in shaft-sinking, as a " capital " expenditure. Practice in classi- fying expenditures in this respect, and the arrangement of ac- counts relative to mine-costs, is so varied that an engineer can satisfy himself only by an examination of the books, if he would know what items are included in the costs. Particularly in considering a " low-grade " proposition, where accurate data are absolutely necessary, it is an immense advantage to be able to determine in detail, by personal investigation, the actual fects.

Of course, the present worth of a mine cannot be determined by the amount of its past dividends ; yet, in many instances, the gross earnings, as represented by the tonnage and value of ore already produced, may have a signal importance in con- sidering the future relation of profits to operating-expenses.

The value of the product of the various stopes, as shown by the record of ore-sales, affords the closest possible check upon the values obtained by sampling the several ore-bodies from which ore has been shipped. A determination of the tonnage and value of " ore in sight " is naturally the first consideration of the engineer. But in his judgment of the mine as an in- vestment, the item of costs is a factor of equal importance. Prom no other source can he obtain such accurate detailed in- formation relative to the costs and charges of mining as from the books and past records of the mine under examination.

The Conduct of an Audit.

Since the mining business is so radically subject to local conditions, it is to be expected that the forms of records and accounts will be varied to suit each special case. And, although the principles of accounting are fixed, there exists almost as great a diversity in the systems of accounts in use as in the forms and registers employed. With due appreciation of the difficulties likely to arise from this lack of uniformity, the following general suggestions are offered as to the manner of conducting a practical audit of mining accounts.

In the majority of instances, a mine is owned and operated by a corporation, the main or financial office of which is far

The Auditing Of A Mining Company'S Accounts. 95

from the mine. This makes it practically necessary to con- sider two sets of accounts : those conducted at the mine, which directly concern the mine-management ; and those belonging to the province of the secretary, which constitute the perma- nent financial records of the company. The mine-office ac- counts, in fall detail, together with vouchers, are usually for- warded at regular intervals to the main office, where a general audit is made, there being at the mine-office but a local audit or checking of the accounts. For the present purpose, how- ever, it may be assumed that all the records are kept and all the accounts conducted in the office at the mine.

lAst of Sooks. — In order to plan an intelligent dissection of the accounts, it is necessary to know how they are put together. To this end it will be well, first, to secure from the person in charge an explanation of the system employed, with a list and description of the books used. Indispensable, of course, to the double-entry set of books usually kept at a mine, are the cash- book, journal and general ledger. In addition to these, and to the several subordinate record-books, blotters, etc., which con- venience demands, a well-regulated system of mine-accounts ought to include books of ore-shipments and of mining-costs. The former should show in detail the lots of ore sold at the mine or shipped, identifying each lot by number, and giving date of shipment, date of payment, weights, terms of settlement, values, and net returns, and also specifying the stope or head- ing in the mine from which the lot was mined. The costs- book, in the nature of an independent or special ledger, is kept to relieve the general ledger of the burden of the many accounts necessary when accurate record is made of the costs chargeable to each separate place of working in the mine. Cost-keeping is one of the niost important departments of mine-accounting; and the costs-book, when properly con- ducted, is a regular monthly statement and analysis of costs, itemizing the cost of labor, material and supplies, and dis- tributing the power- and operating-charges, and the indirect or fixed and general expenses. Moreover, it is also a special ledger, containing an account with each place of working, in which are charged monthly the itemized costs as above, and from which are carried, by journal-entry, the totals only of the month's expenses to a " Costs of Mining " account in the general ledger.

96 The Auditing Of A Mining Company'S Accounts.

The general ledger is considered the principal book, being the source from which is obtained all classified information relative to the financial condition of the business. But it may- be well to suggest that, although this book is the receptacle for all transactions, in whatever book the entries may originate, the ledger itself is generally ignored by courts of law. The " book of original entry," legally defined as that in which the preliminary record or entry of a transaction is first written, is accepted as authority on all questions involved in a transaction or in a series of transactions.

Capital-Stock; TVeasury-Stock ; Working-Capital. — The capital- stock comprises the full amount of the capital authorized to be raised by the charter or articles of incorporation. The treas- ury-stock is the stock, over and above the amount subscribed and paid for when the company is organized, which is set aside and held by the treasurer, to be sold for the purpose of secur- ing funds to carry on operations. If the entire capital-stock was subscribed and the whole amount paid in was absorbed in the purchase of the mine and the necessary equipment, and further capital is needed to carry on work, the stockholders may, by agreement among themselves, instead of increasing the capital-stock, donate pro rata a certain number of shares to be held and sold by the treasurer for working-capital. A working-capital account is sometimes opened with a credit of a certain amount of the subscribed stock or capital, this sum being set apart for use in prosecuting the development of the mine, etc. These accounts should probably receive first atten- tion. An examination of all entries should be made from their origin in the auxiliary books to their final posting in the gen- eral ledger. The principal books auxiliary to the general account-books of a corporation are the subscription-book, in- stallment-book, transfer-book and stock-ledger. The stock- ledger is used solely for carrying accounts with stockholders of their respective holdings in the company. All the other books mentioned are books of original entry, subsidiary to the stock-ledger. Examination of these books should establish the fact that the capital-stock account in the general ledger is cred- ited with the full amount of the authorized capital, whether paid up or not. If it has not been fully paid, an open subscrip- tion-account will probably be found in the ledger, exhibiting

The Auditing Of A Mining Company'S Accounts. 97

the amount of stock subscribed and not paid for. The amount issued and paid in should correspond with the aggregate hold- ings as shown on the stock-ledger. A close scrutiny of the treasury-stock account, or working-capital account, if either exist, should be made, to ascertain the character of the account, and how it was created. If there is treasury-stock on hand, carried as an asset, the amount should be noted.

Cash' Receipts. — complete audit involves a careful and sys- tematic checking of each and every individual transaction during the period under audit. The opening and subsequent entries covering cash-receipts for capital-stock subscriptions paid, and for treasury-stock sold, should be examined and checked. The records of sales of treasury-stock should be critically examined, and the entries traced to their final exhibit on the books. If stock is sold at par, " Cash " will, of course, show the proper debit-entry for the amount received. If dis- posed of at less than par, or if sold at a premium, the entries covering the balance or difference between the amount received and the nominal or par value of the stock, as well as the cash entry, should be carefully investigated. Strictly speaking, the discount on stock sold at less than par is not a loss, nor is the premium on stock sold above par a gain, of the business proper; and the amount in either case will probably be covered into the working-capital rather than the profit-and-loss account. Fre- quently, however, especially if a profit has been realized on- such sale, the amount is carried directly into Profit and Loss Practice varies considerably in the conduct of accounts relat- mg to treasury-stock and working-capital. But in whatever manner transactions of this nature are recorded, an audit will prove its efiiciency if it determines that fictitious values are not given in the accounts representing resources, actual lia- bilities, expenses, or any other account aflfecting profit and loss.

Practically, the only revenue of a mine is derived from the sale of its product, in whatever form (crude ore, concentrates, matte, bullion, etc.) it may be marketed. All items of cash, as hown on the cash-book, should be checked ; but this one principal item should be verified by comparing the receipts, as entered, with the ore-shipment register, and with the settle- ment-sheets or statements rendered by the smelter or other VOL. .— 7

98 Thb Auditing Of A Mining Company'S Accounts.

purchaser. Such a statement is rendered for each shipment separately by all ore-purchasers, or, in the case of a company smelting the ores from its own mine to crude bullion or matte, by the refinery to which this product is sold.

Cash Disbursements. — All items of cash disbursement should be checked and compared with the vouchers or proofs of pay ment.

If the " voucher-system " is employed, and transactions are recorded by classification in a voucher-journal, from which the totals of like debits and credits, instead of individual items, are posted, the work of checking and comparing the itemized expenditures will be confined to this book of first entry. The footings of this journal are then verified, and the posting of aggregate totals is regularly checked.

A critical examination of the vouchers should be made to ascertain whether the payments made were properly authorized and certified.

Pay-rolls should be examined to see that they are properly and duly signed by employees, and that the totals of each are correctly entered.

The balance of cash shown by the books should agree with the amount of cash on hand and in bank, less the amount of outstanding checks not yet presented for payment.

After the purely mechanical checking of all entries in and postings from the cash-book, journal, etc., and the verification of their arithmetical accuracy, the next, and essentially the most important, step is to trace each entry from its inception to its final posting, with the view of detecting errors and irregu- larities, whether of ignorance or of intentional fraud.

This critical examination is of considerable moment, par- ticularly if the audit is made under conditions exacting a close discrimination between expenditures of capital and of revenue.

Capital, — Capital-expenditure accounts are debited with all disbursements which result in the acquirement of something of permanent value.

Such entries require very careful inspection, not merely to prove clerical accuracy in recording the transactions, and the vouchers and receipts covering them, but also the legitimacy of their classification as capital-expenditures. A systematic in-

The Auditing Of A Mining Company'S Accounts. 99

Festigation of the amounts carried to capital, and of all entries of amounts expended and covered into the accounts of build- ings, plants, machinery, equipment, air-pipe lines, water-mains, etc., etc., should aflbrd an approximate verification of the cor- rectness of these property-accounts, and put to proof the fair- ness of the valuation of the several plants carried as assets.

These accounts should be also scrutinized, to see that they are duly credited with amounts written off, from time to time, for depreciation. Such amounts, taken out of income for* deterioration of plant, are usually debited to profit-and-loss direct, bat are sometimes carried by a charge to a depreciation- account

A close discrimination between expenses properly chargeable to capital and to revenue, respectively, is of vital importance ; for it is apparent that if too great a portion of the expense of iny year be charged against capital, then the current expense will appear smaller and the profit correspondingly greater. On the other hand, if the entire cost of plant and equipment, or "f improvements, which, for all practical purposes, may be considered of permanent value, is charged against the operating- trxpense or cost of mining of any year, a true profit with respect to the ordinary working-expenses and receipts may be made to appear as a loss. If the whole, or any portion, of the develop- ment-work of a mine for any year be charged to capital and the current operating-expense be relieved of this cost, the apparent profit will be unduly increased.

In the business of mining, custom has not yet established a iniform method of treating expenditures for renewals and re- firs of machinery, plant and equipment. In fact, the question ''f distinguishing between capital and revenue for sums ex- funded in the original purchase, enlargements and improve- nents of plants is a matter of individual concern and choice. Some companies treat every expenditure for machinery and 'luipment as fairly chargeable to the cost of mining for the jear during which the purchase was made. Practically, this cnahod may be said to be correct; since the sums so expended part of the expense of mining, and must eventually be re- paid by the revenue derived from the sale of the mine's product Other companies are too prone to treat as capital not only the original purchase-price, but all sums expended for

100 The Auditing Of A Mining Company'S Accounts.

improvements, and for renewals and repairs as well. And some companies do, while others do not, make provision for depreciation. In any event, an examination of the accounts should prove that the aggregate amount appearing in capital- accounts as expended for machinery, equipment, etc., is repre- sented by plant of that value, maintained in efficient repair.

As stated, an approximate verification of these amounts can be arrived at by tracing from their source all entries for items so charged. For example, in case a mining-plant is purchased and erected under contract, it is easy to determine its original value by reference to the contract. The erection of plants, the installing of machinery, etc., when done by a company by day's labor, involve a careful consideration of the cost of labor, as well as of material and supplies.

It must be confessed that the wages-account is the most diffi- cult of all to check eflfectually, especially in trying to distin- guish between capital- and revenue-expenditures, when mining operations and construction are carried on simultaneously, and more especially when a company has no system of keeping and correctly recording amounts expended for wages. Where such a system exists, and where the records of one department are examined and checked by another and independent department, it will not be so troublesome to arrive at a comparatively accu- rate proving of the correctness of all wages charged to capital.

Revenue. — In a mining enterprise of any magnitude the debit-side of this account represents the expenditure of con- siderable money. An audit to determine the actual amount, and the correctness of the entries, of expenditure of revenue must be very comprehensive.

The vouchers and receipts, in addition to the checking on the cash-book, must be critically inspected, and the classification and distribution of the expense represented by each voucher must be verified.

Mining-supplies purchased are charged to revenue when used, not necessarily when paid for. This requires an exhaust- ive investigation into the nature and conduct of the stores- accounts, and a complete checking of these accounts, to make sure that all supplies taken from stores are properly charged, when credited to the stores-account. The entries covering

these transactions should be gone into pretty thoroughly. The prices charged for supplies consumed should be compared with the parchase-price and the cost as stated in inventory. An 'mventOTj ought to be taken of all material and supplies on hand, the valaes being compared with the purchase-prices, and the total with the aggregate of the various stores-accounts on the books.

Wages, salaries, and all fixed and general expenses, such as taxes, insurance, etc., are direct cash-disbursements. All these itemsy with the possible exception of wages, can be effectually tested by comparing with the vouchers, and by reference, when neee?ary, to the authority for the payment. For example, the correctness of salaries paid could be ascertained from the direc- tors who had the fixing of salaries ; and of taxes, by comparing the payments with the demands of the government, etc.

In the matter of ages it is impracticable to verify all the items on the pay-rolls which go to make up the aggregate ex- penditure for labor. The distribution and legitimate " expens- ing" of the cost of labor can be fairly tested as explained; but an auditor may be obliged to rely to a considerable extent upon the system of inter-staff corroboration referred to above, and upon the certificate of an official in authority, as to the ve- racity of the various pay-rolls.

If all accounts representing the operating-, fixed and general expense of the business are carried into one account, " Costs of Mining," at regular intervals, a comparison of the entries in this account with the mining-costs book will facilitate a veri- fication of the aggregate expenditure chargeable to revenue.

Personal Accounts. — Personal accounts, accounts and bills receivable, and accounts and bills payable, should be examined carefully. In the business of mining, accounts of this nature are not frequent, and liability of loss from bad debts or doubt- ful accounts is limited. Such accounts, and the contingency of such loss, however, should be considered. The amount of accounts due and bills payable, as shown on the books, should be verified and taken into calculation in determining the gains or losses for the period under audit.

Financial StatemmL — The task of checking and verifying all book-transactions being completed, the footings of all accounts in the ledger, whether closed or still operative, should be tested,

102 Thb Auditing Of A Mining Company'S Accounts.

balances verified, and a trial-balance taken. This trial-balance proving the correctness of the ledger, it is now in order to pre- pare a statement of assets and liabilities, and a statement of profit and loss.

The financial condition of the company should be very clearly set forth in this financial statement, the balance-sheet exhibiting :

Property and Assets.

1. Property, showing mines and min- eral claims, and other real property.

2. ImprovemeniSf showing buildings, machinery, plants, equipment, etc. ; also stores and supplies on hand.

Capital and LiahUities.

1. Capital Stock, showing in detail the number of shares ; amount paid up ; amount, if any, remaining unpaid ; amount and nature of arrearof calls, particulars of forfeited shares, etc.

2. Debts and LiMlitiejs of the com- pany, showing the amount of debts owed by the company, enumerating the same, and distinguishing actual from contingent liabilities, etc These contingent liabilities, such as claims against the company not acknowl- edged as debts, or moneys for which the company is contingently liable, should be stated ; but only the amount of acknowledged debt is carried out as a liability.

3. Cash and Investments showing amount of cash on hand and in bank, the nature of investments, rates of inter- est, etc

4. Debts Owing to the Company showing all debts, accounts and bills receiv- able.

3. Reserve- Fundy showing the amount set aside from profits to meet contin- gencies.

4. Profit and Loss, showing the dispos- able balance for payment of divi- dends, etc.

The statement of profit and loss should state specifically upon what accounts losses have been sustained, and detail the accounts through which profits have been realized. In calcu- lating the gains and losses, it must be borne in mind that the loss or gain of a mining-venture for any given period is not merely the difference between the receipts for ores sold and the costs of mining. Depreciation must always be taken into con- sideration.

the auditing of a mining company's accounts. 103

Redemption op Capital.

In connection with an audit it is essential that the questions of depreciation, dividends, surplus and redemption of capital be taken into account. Most industrial enterprises involve the same elementary principles. But there are considerations in mining which do not affect other kinds of business.

A mine cannot be said to be a permanent source of wealth. Every ton of ore mined and marketed involves a depreciation in the value of the property which cannot be repaired. Hence, during the life of a mine, not only must interest be realized apon the capital invested, but the capital itself must be recov- ered, if the venture is to prove successful. In this respect, de- preciation and dividends may be considered as different causes operating to the same end, namely, the diminution of the value of the property.

Depreciation. — Generally speaking, the loss upon assets which are diminishing in value is called depreciation. As applied to plants, equipment, mining machinery, etc. (provided the origi- nal cost of these items is not treated as a portion of the current operating-expense, and so charged at time of purchase), a cer- tain sum, estimated upon the life of the plant, should be charged against the gross revenue of each year, to replace the capital destroyed or reduced by wear and tear. The method of treat- ing sums expended for plant as current expense is manifestly unfair, both to the management desirous of making a record in the matter of mine-costs and to the present stockholders ; for, in the early stages of a mine, when most of the equipment is purchased, costs will be exaggerated, and dividends which might otherwise be paid may be deferred, by reason of this abnormal increase in the current-expense account. But, since the life of mining machinery is comparatively short, and there is practically no residual value, in case the mine is abandoned as worked out, or the machinery has to be replaced by a plant of greater capacity, it is not only prudent but absolutely necessary that some provision be made to redeem its cost.

Depreciation, as applied to the redemption of the capital in- vested in a mine, provides for the writing off of a certain sum each year, estimated upon the life of a mine, to accumulate a sinking-fund for this purpose.

In the business of mining, however much may be said in

104 The Auditing Of A Mining Company'S Accounts.

favor of some method of accumulating a sinking-fund, such a fund is seldom, if ever, provided for. The individual stock- holder usually thinks that he would prefer to have his capital returned to him as fast as it may be taken from the mine, rather than await the accumulation of a fiind sufficient to re- deem the whole capital. To this end the custom prevails, and will probably be considered the better method, so far as mining is concerned, of repaying capital by dividends. By means of dividends, or, as they might properly be called, enlarged divi- dends, the stockholder, after calculating a fair interest on his investment, can consider the sums received over and above this interest as repayments of the principal of his investment.

This method may be subject to some question, since there are few (except those who have given special thought to the matter) who properly appreciate the difference between a divi- dend which is purely a distribution of profits and a dividend which is intended to repay capital. Then there is this contin- gency to face : in the case of a successful mining enterprise it may be found that the full amount of the company's capital is carried as a liability, when, in fact, it has all been repaid in the shape of dividends; while, on the other side of the balance-sheet, the mine, valued at its original cost and worth, is still shown.

The amount paid in dividends in this way each year may be estimated, or rather will depend, upon the amount of output and the profit realized upon the sale of product.

Dividends. — The term dividend, as generally accepted, means a sum which a corporation sets aside from its profits to be di- vided among its members. It is a fundamental rule that divi- dends shall not be declared or paid when a company is insol- vent, or the payment of which renders a company insolvent. A dividend must be declared from realized, and not from esti- mated, profits. The violation of this rule is not common. But it too frequently happens that when profit does not follow on the heels of promise the directors of a company, anxious to appease the importunity of stockholders, are led to ignore one of the most important precepts of financial prudence. Under this constraint they declare and pay dividends without first having provided a surplus or reserve-fund ; that is, a special fund of profits set aside for the purpose of meeting contingen- cies, or of equalizing dividends.

The Auditing Of A Mining Company'S Accounts. 105

BeserveFund. — If such a fund, set apart from current in- come, or created by withholding a small percentage of the annual net earnings, is shown upon the books, this account should be examined by the auditor, and its accuracy should be tested. The amount should be held, either in actual cash on hand, or on special deposit in bank, or invested in safe and readily convertible securities. A reserve-fund once established dhould be drawn upon only in case of urgent necessity, or to meet exceptional and temporary reverses in profits.

The history of the raining industry is replete with records of companies wrecked by adverse circumstances, by reason of the lack of means with which to carry exploration to a proba- ble successful issue, — means which might have been provided at a time when the mine was earning regular profits. But with working-capital exhausted ; stockholders reluctant to pay assessments or to render themselves personally liable for bor- rowed capital ; the ore-reserves of the mine worked up to their limit, and no reserve-fund to meet the exigency, the mine is abandoned. And thus is recorded another mining failure which a little forethought and business prudence might have averted.

Again, it may occur that a mine in the full flush of prosper- ity is compelled to discontinue dividends for a period. There would be fewer disappointed stockholders, in this respect, if the policy of providing a surplus were rigidly insisted upon. Regu- lar dividends could be continued, and a most distressing period in the afiairs of a mining company could be safely tided over if, daring its most profitable period, provision had been made for such a crisis.

General Remarks.

As has been observed, and will no doubt be confirmed by the experience of most mining engineers, there is a noticeable lack of uniformity in the systems of keeping mine-accounts. Such irregularity in the matter of registering and recording the routine of business details at the mine may be attributed to arbitrary local conditions. But the absence of uniform sys- tem in the more important departments of accounting, espe- cially in the treatment of expenditures and in respect to mine- corts, must be ascribed, in part at least, to the scarcity of practical literature on the subject, and to the lack of active

106 The Auditing Of A Mining Company'S Accounts.

discussion of the questions involved by those most vitally inter- ested. In all other important productive industries, a consider- able degree of conformity, not only in general system, but in details of shop-organization, cost-keeping, etc., has been estab- lished. This uniformity obtains, to a greater or less extent, even in manufacturing and mercantile pursuits, where processes and mechanical methods, locality, competition, and other con- flicting influences, affect trade-conditions.

It is not intended to insist pedantically upon similarity of forms, methods, and like details, nor is it deemed necessary-, on the other hand, to formulate the reasons for a generally uniform practice with respect to mine-accounts ; but it may not be amiss to offer the opinion that in no other way can uniformity be secured except by concerted effort on the part of those who are actively interested in all that pertains to the economy of modern mining.

If, in connection with the many discussions relevant to the science and practice of mining, the business side of the ques- tion could receive the attention it deserves ; if the interchange of ideas and opinions by those whose authority and interest are unquestioned were more frequent and general, reforms in this direction could be induced. By urging the adoption of a few conservative rules and principles of business which would tend to safeguard the commercial interests of mining, and by- pressing the importance of a practicable uniformity in system and method, the engineering profession could increase the credit which it has already earned by what it has done to ad- vance the business of mining from the plane of mere speculative gambling to its present high rank among the prosperous pro- ductive industries.

Effect Of Re-Heating On Over-Heated Steel. 107

The Effect of Re-Heating upon the Coarse Structure of Over-Heated Steel.*

BY K. FREDRIK OORANSSON, 8ANDVIKEN, SWEDEN. (New York and Philadelphia Meeting. February and May, 1902.)

Introduction.

The structure of steel, when rendered coarse by over-heating, is made fine by re-heating to a certain temperature, the deter- mination of which has received much attention from eminent metallnrgieal authorities. Among these, I may particularly mention Prof. D. Tschernoff* [Chernoff] , who, about thirty years ago, studied this question in connection with his investigations on the structure of steel in general.!

Some years later, Mr. J. A. Brinell took up the inquiry, and arrived at many important conclusions, stated in his well-known rales on the treatment of steel. J

These two gentlemen, however, based their reasoning chiefly upon the aspect of fractures — a method which, though it affords valuable information, does not readily reveal the different steps by which a change in structure takes place.

For fiirther light on the subject, we owe much to more recent microscopic investigations, which have made us better ac- quainted with the internal structure of metals. Such an in- vestigation, closely connected with the present subject, and made by !Mr. John E. Stead a few years ago, was first published in 1898. §

Secbetaby's Note. — This paper is substantially a thesis presented by the Butlior in May, 1901, to the Faculty of Science of Columbia University, in New York. By consent of the Council, it is published also in the Swedish language by the Jemkcntoret of Sweden. Members of the Institute will be interested to know that the author is the grandson of G. F. Goransson, whose experiments and improTements contributed essentially to the first practical success of the Bessemer process. (See the paper of Prof. Akerman, Tram., xxii., 265.) R W. R.

t "On the Manufacture of Steel and the Mode of Working It." (May, 1868.) Truislated in Proc. Inst. Mech, Eng., April, 1880, p. 286.

X '*The Changes in the Texture of Steel on Heating and on Cooling," Jemk. Amu, 1885, vol. xL, pp 9-38. Abstracted in Jour. I. and S. Inst., 1886, No. 1, pfk. 365-367. German translation in Stahl u. Eisen vol. v., 611.

i "The Crystalline Structure of Iron and Steel," Jour. I. and S. InsL, 1898, 5o. 1, pp. 145-189; also, The Metallographiit, vol. i., p. 289, Oct., 1898.

108 Effect Of Re-Heating On Over-Heated Steel.

Regarding the cause of the disappearance of the coarse struc- ture, as the result of annealing, Mr. Stead's observations led him to conclusions somewhat modifying, or, at least, rendering more complete, those of earlier investigators.

Mr. Brinell found that the refinement of structure takes pljuje at the same temperature as the transformation of the cements carbon into hardening-carbon, and concluded that the very violence of the transformation destroys all previous crystalliza- tion.

Mr. Stead, however, in examining the micro-structure of a piece of over-heated iron, containing 0.11 per cent, of carbon, which had been re-heated to 830° C, and then slowly cooled, found evidences of another factor, namely, the diffusion of the carbon into the grains of ferrite. He says:*

. . . The pearlite was redistributed between the grains, and it could be

easily seen to what point the carbon had diffused Where the carbon has

diffuJsed into the ferrite, its coarse structure is broken up. We conclude from these results that the breaking up of the coarse structure in carbon-steels is not due only, as Brinell maintains, to the coincident change of cement- to hardening-carbon, but also to the carbon diffusing after such a change has been effected."

The aim of my investigation has been to collect additional facts which might be useful in the further study of this prob- lem.

The steel I studied was a Swedish Bessemer steel, rolled to bars of by in. It contained :

Percent.

Carbon 1.200

Phosphorus, 0.028

Silicon, 0.030

Sulphur, 0.002

Manganese, 0.230

The plan pursued in the investigation was : 1. To find the critical range of the steel ; 2. To over-heat it, in order to get a coarse structure ; 3. To re-heat it to various temperatures, at and about the critical range ; 4. To study the effect of these heatings upon the micro-structure.

I. Heating- and Cooling-Curves. In order to find the critical range of the steel, several heating- and cooling-curves were plotted. Some of these curves are

Loc cU., p. 166.

Effect Of Re-Hbating On Ovbr-Heated Steel.

shown in Figs. 1 and 2. Only one retardation-point could be detected within the range of the experiment (575° to 1060° C). This retardation took place at 740° to 755° C. in heating, and at 690° to 700° C. in cooling, and seems to indicate the point " A„ ;" that is, the temperature at which the eutectic pearlite changes into martensite, and vice versa.*

Fig. 1.

Tima in Seconds

Heatiog-Corves of Steel, Containing 1.20 Per Cent. Carbon.

n. Over-Heating. For over-heating, the bar was cut up into pieces of 3 in. in length, heated to about 1270° C, and then cooled slowly with the furnace, reaching a black heat after three-quarters of an hour. The over-heated steel was then cut into lengths of 1.5 in., and re-heated to the following temperatures :

In ooDDection with these curves, I would say that in tbe case of one of the rauiiiigi for the heating-carve (corve 6, Fig. 1), the pyrometer indicated a fall of temperAtoie at the retardation-point Th movement of the pyrometer was steady ; sod I do not think this apparent fall was caused by any defect of tlie instrument. In this special case Aci seems to have been somewhat delayed ; and perhaps tliis fKt caused the transformation to be more violent than usua].

I do not think it would be proper to make general inferences from the appear- aaee of these few carves ; but I desire to point out that in those cases (6 and r, Fig. 1) where the retardation began at a comparatively high temperature, it was completed at a comparatively low temperature.

110 Effect Of Re-Heating On Over-Heated Steel.

T.max Treatment.

C, Immediately cooled.

887° Immediately cooled.

850° " Immediately cooled.

816° " Immediately cooled.

790° " Immediately cooled.

765° Kept at 760° for 1.5 h.

760° " Immediately cooled.

748° " Immediately cooled.

(AcO

726° Kept at 725° for 2 h.

726° Immediately cooled.

712°** Kept at 695° for 1.5 h.

680° " Kept at 660° for 2 h.

675° Immediately cooled.

675° Kept at 670° for 2 h.

626° Kept at 625° for 2 h.

575°" Kept at 575° for 2 h.

The coolings w.ere made naturally, in the air.

In examining the micro-structures, it was found that the over-heating had changed the original fine structure into a coarse net-work of cementite, enclosing large polygons of pearl- ite. The size of these polygons varied very much. In general, they were smallest in the center of the bar ; but, even in a given region of the same specimen, the variation was considerable. This fact made accurate measurings of the size of the grains rather difficult.

The internal structure of the grains* showed well-laminated flakes of pearlite, with, here and there, isolated lumps and lines of cementite, which, in some specimens, had the form of straight needles, crossing each other apparently at an angle

of 60°.

III. Rb-Heating.

Re-heating to points below ACi seemed to have no effect on the shape and size of the over-heated grains. Their internal structure, however, was slightly changed in specimens "soaked " for a couple of hours at a temperature closely below Ar, (but not at lower temperatures). This change consisted in the formation of rings of cementite, isolating small lumps of pearlite in the interior of the grains. It would seem that these rings were

Secretary's Note. — The original text of this paper was accompanied with micro-photographic, which have not been reproduced for this publication of it. Thej are given in the version published in Jei-nkonloreis AmutUr, June, 1902.

EFFECT OF RE-HEATING ON OVER-HEATED STEEL. Ill

caused by a flow of the cementite, which, during the soaking, might have had more time to arrange itself than it had during the continuous cooling of the over-heated piece. The rings had collected in certain parts of the grains, leaving other parts ap- parently unchanged. The laminated aspect of the peariite was apparently the same after this soaking as before.*

When the re-heating passes Ac the changes are more pro- nounced. A t\vo-fold transformation seems to take place : (a) a sudden change in the internal structure of the grains ; and (6) a gradual change in their boundaries.

Fig. 2.

Time in Minutes .

Cooling-Curves of Steel Containing 1.20 Per Cent. Carbon.

a. The previous lamination of the peariite is broken up and the new peariite is rather badly laminated, if it can be called

AboDt nine months after the completion of the experiment here described, a fHoe of over-heated, but not re-heated, steel, which had not exhibited such rings opon the first examination, was re-examined, and was then found to contain them, ihhoogh to a smaller extent than was shown in the re-heated specimens. The Qolrnew manipulation which this piece had undergone was repolishing and re- etehing— the latter being performed with dilute nitric acid, in the same manner as before. ThL observation, if confirmed by similar ones, would indicate that the formation of the cementite rings takes place in cold steel, if sufiicient time be ailoved for it.

112 Effect Of Rb-Hbatinq On Over-Heated Steel.

laminated at all. Etching with 20-per-cent. nitric acid makes it appear as a dark mass, covered with a multitude of small dots of cementite, looking like pin-holes. These dots are pretty uniformly distributed over the surface, but many of them show a tendency to arrange themselves into rings and short rows. In some places, even, the dots unite, making con- tinuous lines instead of dotted ones ; but this is not generally the case. Only when the re-heating temperature passes 800° C. do they show a stronger tendency to melt together. In that case, the union of some of the dots may effect a more definite lamination of the pearlite, while others form a net-work of ce- mentite, enclosing a new set of grains inside the old ones. These new grains are rather small and irregular ; but, as the temper- ature rises, they grow larger, and assume a polygonal form, ac- companied by a more regular lamination of the pearlite.

b. As to the changes produced in the boundaries of the old grains, it may be said that, if re-heating barely passes the retardation point, it has no appreciable effect upon the old net- work of cementite ; but, as the temperature rises still higher, the net-work becomes disconnected and loses itself in the finer net-work of the new grains above described. This change is very gradual, and is not completed until jsl temperature more than 100° C. above the retardation point has been reached. That the transformation is a question of temperature, rather than of time, is shown by the fact that, in specimens soaked at 760° C. for 1.5 h., the old network was still well-preserved.

IV. Theoretical Inferences.

The above observations seem to indicate that the destruc- tion of the coarse net-work of cementite is caused by its carbon being dissolved in the martensite, and that the net-work sur- rounding the new grains is formed by the expulsion of cemen- tite from the martensite as it is being cooled.

It is important to distinguish between the formation of the grains and the formation of the net-work of cementite between them, for it is probable (and is generally held) that the grains exist in the martensite even at the highest temperatures, and that they are caused by a tendency of the particles of marten- site to arrange themselves in certain directions. It also seenis that, the higher the temperature, the more effect has this ten- dency, and the larger are the resulting grains.

Effect Of Rb-Heating On Over-Heated Steel. 113

Daring the cooling, cementite is expelled from the marten- sitp aod seems to collect between the grains, broaden the boundaries, and enable us to detect them by the microscope.

Xow, the cementite expelled in the over-heated steel forms a much coarser net-work than that expelled in the re-heated steel. This fact may indicate that the polarization of the martensite into coarse grains has been destroyed between the two processes of expulsion.*

When should this destruction of the polarization have taken place ? It seems to me that we have two possibilities : Either the destruction of the polarization might have taken place when the re-heating reached Acj — in which case we approach the view held by Mr. Brinell ; or the destruction of the polariza- tion might have already taken place when the over-heated steel, during its cooling, passed the recalescence-point. According to this hypothesis, the coarse net-work of cementite was then already formed, and served to preserve the coarse structure of the steel, even though the polarization of the particles no

longer existed, f

V. Practical Conclusions.

To the practical question. What re-heating temperature is needed in order to break up the coarse structure ? the reply, on the above theory, would be that we have to heat the steel to the point where aU the cementite has been dissolved by the martensite. And this seems to be, in fact, the case ; for, in the experiments here described, where the steel had been re- heated to 850° C, there were many of the old large grains remaining; but where the re-heating had reached 887° C, the large grains had completely disappeared.

According to the curves of Sir W. C. Roberts- Austen and of Prof. Roozeboom,J the cementite of a 1.20-per-cent. carbon-

A fact which poesibly might indicate a destruction of this polarization is the dotted or imperfectly laminated aspect of pearlite formed in cooling from temperatares slightly above the retardation-point. We do not yet know the cause of the lamination of pearlite ; but if it has something to do with a polariza Hod of the martensite, it would seem natural that an imperfect polarization, such might be produced at the lower temperatures, would go hand-in-hand with an imperfect lamination of the pearlite.

t This soppoaition is favored by the rearrangement of the cementite, already nentinmed, in specimens re-heated to points closely below Acj and kept there for umetime.

I The MtiaUognsphUt, vol. iv., p. 154, April, 1901. Toi* xxxin.— 8

114 Effect Of Rb-Hbating On Over-Heated Steel.

steel begins to fall out from the martensite at about 870° to 880° C, that is, at a temperature intermediate between the re-heating temperatures of 850° C. and 887°C., determined in these experiments.

Whether this theory is valid for hypo-eutectic steels also, future experiments must decide. It may, however, be of inter- est to point out that Mr. Stead, in the experiments on the crys- talline structure of iron and steel, reported in his paper already cited, found a refinement of the grains at 900° C. for steel of 0.01 per <;ent., and at 870° C. for steel of 0.11 per cent, carbon, and that these two points correspond to the temperatures at which, for such steels respectively, the ferrite begins to fall out from the martensite.

POSTSCRIPT. By Henry M. Howe, New York City.

The work described in this paper was undertaken as a step toward studying the coarsening of the grain of steel which takes place as the temperature is progressively raised above the critical range, and the refining of the grain by re-heating to that range. A recapitulation of the points shown by the investigation will facilitate an explanation of their significance.

When steel, the grain of which has been made extremely coarse by greatly over-heating it, is cooled and subsequently re-heated (for instance, as a step in annealing), the following changes occur :

1. Segregation below Ac. — At a temperature slightly below Acj, cementite seems to segregate into rings, apparently be- cause of surface tension. Mr. Goransson has furnished, so far, only slight hints as to this action.

2. Behavior of the Net- Work of Cementite. — If the temperature is carried above Acj, the cementite net-work is progressively- re-absorbed by the grains of martensite which it surrounds. A part of Roberts-Austen's diagram, reproduced in Fig. 3, shows that, in the cooling of such hyper-eutectic steel from about 950° (Arg) to 690° (Ar2.i), in which range the mass of the material is in the condition of martensite, the solvent power of this mar- tensite for cementite progressively diminishes, so that cementite progressively separates out within the martensite, forming itself

Eppect Of Bb-Hbating On Over-Heated Steel.

ioto a net-work, the coarseness of which is proportionate, roughly speaking, to the temperature to which the steel had been previously heated, or, in other words, to what I have been in the habit of calling " T. max." Ifow, the re-absorption of the net-work of cementite, which

Fig. 3.

J100

l?1

! 800

nil

t;

I'

Iron

y

\t.

Tensite Is Hef

E Resolved

i Ar2 ! 70O

Oc

Iron

; Arl

i60O

Into Eutectic

Pearlite

Pearli Oc Feri

Fe 1 :Ite 1

Pear

.Ite Ntite

-1,

QLl

CoolingOarres of Hyper- Eutectic Steel, Modified from Roberts- Austen' s Diagram. i The abscissas refer to percentage of carbon.

Mr. Goransson has observed, is simply the converse of this. Aa the temperature rises from Ac,.! toward Acj the solvent power of the martensite progressively increases ; that is, the inartenflite is able to re-dissolve more and more of the pre- sly-formed cementite net-work. This progressive increase

116 Effect Of Re-Heating On Over-Heated Steel.

in the solvent power of the martensite for cementite, and the simultaneous increase in the ease of diffusion with rise of tem- perature, suffice to explain readily the progressive re-absorption and final disappearance of the net-work of cementite. Mr. Goransson's observations in this respect confirm earlier (un- published) observations of my own.

When hyper-eutectic steel is heated above the critical range, and thus passes into the condition of martensite, and is then subsequently cooled, and thus changed back into pearlite and cementite, the net-work of the cementite is coarser, the higher the temperature to which the steel has been heated. It is an important question, whether this progressive coarsening of the cementite net-work is due to progressive change in the polarization of the martensite or in that of the cementite itself. It is true that in martensite which is free from this net-work of cementite, it has not yet been found possible to distinguish exactly this form of progressive coarsening. In my opinion, however, this is only because we have not yet learned how to detect this change in the martensite. So far as Mr. Gorans- son's observations go, there is nothing to show that the cause of coarsening is not a progressive change in the polarization of the cementite, corresponding to the temperature at which the cementite begins to separate out of the martensite in cooling. This temperature would be T. max., provided that T. max. does not rise above Ac, — as may indeed have been the case in his experiments. However, in the steel which Mr. Sauveur and I examined,* we found that this coarsening continued at tem- peratures far above Acj, — at temperatures, consequently, at which no cementite existed. In my opinion, this shows that the progressive coarsening of the grain is due to a change in the polarization of the martensite and not of the cementite, since the temperature at which the cementite would begin to form in cooling would be one and the same, viz., Ar„ no matter whether T. max. has been only slightly, or very far, above Acj.

8. The Formation of a New Net- Work of Cementite Obsem-ed by Mr. Goransson. — When the over-heated and then cooled steel is re-heated to between Acj. and Acj, for instance to 800° C. part of the cementite, which in the former cooling had become insoluble and had therefore separated out between 800 and

See Eng. andMin. Jour., vol. Ix., Dec. 7, 1896, p. 537.

Bfpect Of Rb-Heating On Over-Heated Steel. 117

Afj,,, again re-dissolves and diffuses into the surrounding mar- tensite. When the steel is now again cooled, the solvent power of the martensite for cementite again decreases ; hence the cementite which had been re-absorbed is now re-expelled, and in this new expulsion forms a new net-work. It is in accordance with the views which I have just expressed that the coarseness of this new net-work of cementite increases with T. max.

4. Blurring and Subsequent Re-Clearing of Pearlite, — Mr. Gor- ansson observes that if the steel be heated only slightly above Ac,.,, the pearlite found in it after re-cooling is blurred. If, however, the heating be carried somewhat higher, the pearlite i? again cleared. An obvious explanation suggests itself. The original pearlite was formed through slow cooling from downward, which splits up the martensite into alternate layers of ferrite and cementite. On re-heating past Acj.j, these tend to re-combine to form martensite again ; but at the relatively low temperature at which this occurs, and in the relatively rigid state of the metal, the re-combination and diffusion of the sheetlets of ferrite and cementite into each other are rela- tively slow. If we arrest the heating when the temperature has passed only very little above Ac,, this diffusion is incom- plete, so that traces of the former pearlite structure remain in red-hot metal. When this now cools below Ar.,, and the mar- tensite formed by this imperfect diffusion again resolves itself into pearlite, we can hardly expect that the new pearlite will be well laminated ; for such good lamination should occur only when the original mass in which the pearlite forms is approxi- mately homogeneous. Under the conditions which we have been assuming, the structure of the old pearlite may be expected to cross that of the new. Consider two adjoining sheetlets of the original ferrite and cementite ; suppose that, with the heat- ing past Ac,, they had diffused so far that but one-quarter of them had re-constituted martensite of the pearlite composition (viz., 0.80 per cent, carbon), but that on either side of this band there were regions of hyper-eutectic and hypo-eutectic marten- site respectively. In their recombination, then, these two sheet- lets will have formed at this moment a flake of martensite of very heterogeneous composition; and this heterogeneousness i:3 quite sufficient to explain why, when the martensite again splits up into pearlite, that pearlite should be irregular, as re- ported by Mr. Goransson, instead of being well-laminated.

118 Effbot Of Re-Hgatixg On Oveb-Heated Steel.

As the distance above Acj.j to which the re-heating is carried is progressively increased, so should the difiusion of the ferrite and cementite, and the homogeneousness of the resultant mar- tensite, increase ; and so should the regularity of the pearlite, which, in turn, results from the re-decomposition of that mar- tensite on again cooling, increase. Thus may the blurring and re-clearing of the pearlite be explained.

The explanation of the clouding and clearing of the pearlite can be tested in a simple way, which will probably be carried out in my laboratory. It is as follows : Heat a series of speci- mens of steel to temperatures varying progressively from barely above Ac to a temperature high enough to bring about the clearing of the pearlite; but, instead of cooling them slowly so as to form new pearlite, quench them in water. If my ex- planation is correct, then those quenched from temperatures only slightly above Acj-i should exhibit traces of the old pearlite structure, whereas those quenched from higher temperatures should show no such traces. Osmond has given the first indications in this direction in his masterly Methode GinireUe* in which he figures the diffusion of the ferrite and cementite into each other in passing through the stage of sorbite.

5. Mr. Goransson's observation, that the polygons are smaller in the center than toward the outside of the specimens, agrees with older observations on fracture, and tends to bring fracture and micro-structure into harmony.f

BuU, Soe. d? Encouragement May, 1895, pp. 36-61 of extract; see preferably the reprint in the 'Contribution a T Etude des AUiages," {SocUU d? Eneouragnnent 1901, p. 277.

t CJompare Discussion of Metcalf, Trans, Am. Soc, Civ. Eng., zvi., p. 388, and the writer's Metallurgy of Steel, p. 176.

Gold Mining In Mcduffie County, Georgia. 119

Gold Mining in McDuffie County, Georgia.

By W. H. Flukbr, Tatham, Georgia.

(New York and Philadelphia Meeting, Febraary and May, 1902.)

McDuFFiE COUNTY, ODce a part of Columbia county, lies in the eastern part of central Georgia, about 20 miles west of the Savannah river, and bounded on the northwest by Little river. Wrightsboro, now almost forgotten, was one of the principal towns of Georgia before the Revolutionary war, and much of the land hereafter described as belonng to one of the princi- pal gold-bearing sections of the South had been taken up by the early agricultural settlers, and was already under cultiva- tion. Indeed, some of the present mining companies can trace their chain of title back to the original grant of King George EL, made in 1771. The first discovery of gold in Georgia, however, was not made until 1823, when two English miners, who had emigrated to this country and were traveling as ped- dlers through this section, discovered quartz, rich in gold, on what ia now known as " the 40-acre lot," and owned by the Columbia Mining Co. These men had no money to buy the lands, and not being able to stake oS a claim and begin work, as is the custom in other places, they were forced to seek the aid of the native farmers. In this we are told that they were for a long time unsuccessful ; the farmers and land-owners not know- ing or caring anything about gold mining.

In 1826, Jeremiah Griffin, a wealthy farmer, became inter- ested with them, and they did some prospecting and located several rich veins. Mr. Griffin soon became enthusiastic, and bought about three thousand acres of supposed gold-lands, lying along Little river. This purchase was unfortunate for the mining industry, as it effectually shut out all other pros- pectors, and confined entirely to Mr. Griffin and his associates the mining development of the whole region. As a conse- quence, the ground was never covered, and there are virgin lands in this section now, which offer to the prospector as

120 GOLD MINING IN McDUPPIE COUNTY, GEORGIA.

much hope of reward as the unexplored lands of any part of the world that I know of.

The gold-belt is about two miles wide, and extends from Hancock county on the southwest, through Warren, McDuffie and Lincoln counties in Georgia, and, crossing the Savannah river, through South and N'orth Carolina. The country-rock is usually hydromica-schist on both walls, although some of the principal veins lie along the line of contact between the hydro- mica-schist and the granite and gneiss, which constitute the country-rock of the region lying ]S W. of the belt

AVhile no geologist has yet decided to what particular geological period these veins and rocks belong, it is believed that they are of entirely diflferent and much more recent forma- tion than those of the Dahlonega district

The gold occurs in fissure-veins, which usually strike about K". 50° E. (the general strike of the formation), and usually dip, with the formation, about 60° NW.

They frequently continue in an almost unbroken line, with regular dip and strike, for several miles, although, of course, they vary in thickness from mere gravel seams to zones many feet wide. The material, a hard, massive quartz, occurs, not in lenses, but in shoots, which pitch to the north, and continue downward with uniform thickness as deep as any work has yet been done. The veins are separated from the country-rock by the usual few inches of gouge, and frequently show a ribbon or banded structure ; it is often along the faces formed by the banding that the finest specimens of free gold are found. Whether this banding occurs or not, however, the gold is found, as a general rule, thoroughly distributed throughout the entire vein. Auriferous pyrites occurs in all the veins, par- ticularly below water-level, and the concentrates of this char- acter show by assay a value of from $100 to J300 per ton. The minerals which nearly always accompany the gold, and are usually regarded as indications of it, are iron and copper pyrites, g*alena, and pyroniorphite — the latter being considered a sign of very rich ore.

The quartz is usually very clean, and the gold is coarse. The absence of slimes in the crushed product makes both amalgamation and concentration simple and easy.

Almost from the date of discovery, these mines have been

GOLD MINIKG IN McDUFFIB COUNTY, GEORGIA. 121

successfully and profitably worked. Exceptions there have been, of course ; but they are by no means so numerous as to make the McDuffie mines difierent in this respect from other gold-mines of the world.

In 1833, Jeremiah Griffin purchased the rights of his asso- ciates, who had up to this time confined their work to placer- mining on a small scale. He erected a stamp-mill, the old mortars of which can now be seen, near the point on Little river where the mill was first used in 1833. They were rec- tangular in shape, 10 in. wide by 14 in. deep and 30 in. long. Xo dies were used, and there was no discharge. The stamps, of which there were three, consisted each of a square cast-iron shoe, with a square tapering neck, about 8 in. long. The neck was driven into a hole mortised in the end of a wooden stem 6 in. square and 7 ft. long, around which was placed a heavy iron band, to prevent splitting. The cam-shaft was a solid piece of wood 26 in. in diameter, with blocks, which served as cams, mortised into it. These, in revolving, came ' a con- tact with other blocks, serving as tappets, which were fast- ened to the wooden stem by means of iron bands and wooden pegs or dowel-pins. The mill was driven by an under-shot water-wheel, the shaft of which was a continuation of the cam-shaft. The mortars described above were soon replaced by wooden mortars provided with a discharge and screen, sim- ilar to those used at the present time, and having a single cast- iron die, which extended the entire length of the mortar. With such a mill, which was probably the first stamp-mill erected in America, Jeremiah Griffin, in the year 1837, cleared $80,000.00. The ore that he milled was nearly all taken from what is now called the Columbia vein on " the 40-acre lot," — a vein which is still profitably worked.

In 1842, Mr. Griffin, still actively engaged in mining, was accidentally killed, and left a large fortune to his numerous heirs, who continued to work the mine until 1851, when it was sold to the Columbia Mining Company, which worked it with great success until the beginning of the Civil War, which put an end to this and all like industries in the South. The men, and such of the machinery as could be used, were required in the flenice of the Confederate Government, and the entire equip- ment was confiscated and moved away during the war.

122 GOLD MINING IN McDUPPIE COUNTY, GEORGIA.

At the close of the war, the South was left in an impover- ished and helpless condition. In the preceding period, slaves belonging to the various mining companies had been worked in the mines. After the war, these slaves were free ; and even if the money and machinery for reopening the mines could have been obtained, there was no labor. As a result of these conditions, most of these mines have until recently been prac- tically abandoned. A few, however, have been worked contin- uously in spite of all difficulties.

The Parks mine was owned and operated successfully by Col. J. Belknap Smith until his death, in 1888, after which the work was continued dthout interruption by his widow, under whose personal management the business was profitably con- ducted until 1899, when she leased it to a company of western miners. The principal work done on this property by her was in sinking the Parks shaft to the depth of 150 ft., and running drifts to a considerable distance in each direction, along the vein. This vein lies northwest of the center of the belt, strikes almost at right angles to the general strike of the formation, and is nearly vertical. It varies in thickness from 2 to 11 ft., and in value from $10 to J200 per ton. The average free- gold value of ore mined for three years in this vein was $34.60 per ton ; and assays show that fully half the total value of the ore was contained in the sulphides, which for about 40 years have been allowed to flow into the river below the mill. Little or no improved machinery was employed by Mrs. Smith. The ore had been so rich in free gold, and had been so easily treated, that it never seemed to her to be necessary to go to the trouble and expense of concentration ; and she made no attempt to save anything but the free gold.

This property, which contains 105 acres, is traversed by numerous other veins. Several of them have been worked with profit to a depth of from 60 to 120 ft. Below this depth, the values are largely contained in the sulphides and it has not been found profitable to work the lower ground for fi'ee old only.

James Frank, on what is now known as the National mine, was also very successful, developing several veins to the depth of fi'om 50 to 75 ft., and finding free-gold values, varying from $4 to $20 per ton. Mr. Frank made no attempt to concentrate

GOLD MINING IN McDUFFIE COUNTY, GEORGIA. 12S

his ore; and when he reached the point below water-level where the sulphides were no longer decomposed and the values could not be obtained by amalgamation, he, like all the rest,, concluded that the ore was worthless, and abandoned that working to begin again on some other vein. In 1893, Mr. Frank sold his mine to Gen. Joseph H. Porter of New York, who did considerable development-work on the property, sink- ing the Egypt and Brock shafts to the depth of 110 ft. The ore was found satisfactory, aijd he began the erection of a modern mill, but died before its completion. In 1897 the property was sold to the Four Oaks Mining Co., and in 1899 to the National Mining Co. of Chicago. This company now has a modern 20-stamp miill practically complete, in which one Wilfley and one Bartlett concentrator are used, and are said to give excel- lent results. The company has sunk the Brock shaft to about 140 ft., and drifted about 75 ft. along the vein. The vein at this level is 4 ft. thick; and an average sample assayed $21.40 per ton.

The Tatham mine, though not now worked, has several years of profitable operation to its credit; and it is understood that preparations are now making to reopen the Slate shaft, which was worked by Tatham Brothers of Philadelphia for a number of years, and has the reputation of having supplied ore that yielded $2000 per ton by amalgamation. There is a 10-stamp mill, with Wilfley concentrators, on this property.

The Landers mine is a new discovery and has only been worked a few months. Two veins varying from 6 in. to 18 in. in thickness have been located on the property, and are said to assay from f 20 to $30 per ton. No machinery has been put on this property and none of the ore has been milled.

The Woodall mine is now idle on a<5count of litigation ; but, when shut down, it was yielding ore said to be worth $50 per ton, from a vein averaging 16 in. in thickness, and at a depth of 100 ft.

The 40-acre lot of the Columbia mine has been, both before and since the Civil War, the most extensively worked property in McDuffie county. As the place of the first discovery of gold in Georgia, it has naturally been a center of operations ; and the success of Jeremiah Griffin, John and Lewis Parks, Henry Leitner, J. Belknap Smith and others bears witness to the rich-

124 GOLD MINING IN McDUFFIB COUNTY, GEORGIA.

ness and continuity of the veins. Although 200 ft. is the great- est depth reached by any of these miners before the war, records kept by Col. Smith show that more than $2,000,000 has been extracted from ore mined on this property. The 40-acre lot is almost square, and, like the Parks, lies slightly NW. of the center of the belt. It is traversed by what, at the depth thus far attained, seems to be two systems of veins, the Columbia and the Bell. The Bell is farthest north, and is now worked at the depth of 140 ft. by the Columbia Mining Co. The ore is found to be valuable both in free gold and in sulphides. Ore from this vein is now yielding in free gold about $17 per ton, which is about half the assay-value. The foot-wall of the vein is hydro-mica slate. The hanging-wall is gneiss, and is sepa- rated from the quartz by from 1 to 3 in. of gouge, while the slate in the foot-wall seems almost blended with the quartz, and is impregnated with cubes of pyrite, which give the slate a gold-value of about $4 per ton for a distance of 10 ft. from the vein, which is as far as prospecting has gone. This vein fol- lows the general strike of the country-rock, about N. 50° E., and dips 60° ISTW. It has been drifted on for 565 ft, showing a continuous vein of almost uniform values.

The Columbia vein lies about 600 ft. S. of the Bell, and is the larger of the two. It is nearly parallel to the Bell, but dips 45° NW. Both walls are hydro-mica schist, and are sepa- rated from the quartz by the usual thickness of gouge. The foot-wall is regular and unbroken, while numerous spurs branch out from the hanging-wall towards the Bell. The vein varies in thickness from 2 to 20 ft, and in value from $2 to $100 per ton. The deepest work has been done by the present own- ers in an incline shaft, now 325 ft. deep, at the bottom of which the vein is 5 ft thick and assays $32.20 per ton. Drifts have been run on the vein at several points. At the 175-ft level the drift is 720 ft. long, and shows a continuous ore-body. From other cuts and shafts on the surface along the line of strike, this vein is known to continue for a long distance on each side of the shaft. Thus far, the work of the Columbia Mining Co., which has been operating the mine since June 1, 1899, has been done for the purpose of developing the prop- erty. Numerous shafts have been sunk, and pay-ore has been found in most of them. The work has been done in a substan-

The I>Ikect Cyaniding Of Wet-Crushed Ores. 125

tial and permanent manner, and it is proposed to extend the present incline shaft to a depth of 1000 ft. The companj- has erected on its property a 10-stamp mill with Wilfley concen- trators, and lias run constantly for the past two years on ore that has averaged $9.20 per ton in free gold. The concen- trates have not yet been turned into money, but are stored at the mine, and vrill probably be shipped to a smelter for treat- ment. One lot of these concentrates, shipped to the Southern smelter at Atlanta, Ga., netted about J82 per ton.

There are numerous other veins and prospects, not only in McDnffie, but also in Warren and Lincoln counties, some of which are worked profitably at this time, but nearly always on a limited scale. Inexperience and lack of capital are the two drawbacks to the prosperity of mining in this section. When these shall have been overcome, McDuffie county will take its place among the great gold-producing districts of the United States.

The Direct Cyaniding of Wet-Crushed Ores in New

Zealand.

BT HAMILTON WINGATE, B.SC, AUCKLAND, N. Z. (New Haven Meeting, October, 1902.)

Until recently, the universal practice in New Zealand was dry-crushing and direct cyaniding. "With ores containing no mineral sulphides, and little or no coarse gold, this method, in spite of its many disadvantages, gave excellent results, and was by far the best one available, pending the solution of the slimes-problem. But the situation has now been changed. The SQccessfiil treatment of the slimes, enabling the mines not only to do away with dry-crushing, but also to deal with the miner- alized ores of the lower levels, which are, for obvious reasons, quite nnsuited to that method of treatment, has made wet- cmshing universal ; and this may be taken as satisfactory proof of its superiority over the former practice.

In the lack of accurate information from plants operating sacoessfully, particulars of experimental trials carried out on a working-scale at the Waitekauri Extended mine, Maratoto,

126 The Direct Cyaniding Of Wet-Crushed Ores.

K". Z., while the writer was in charge of the cyanide- works, may be interesting to members of the Institute.

At this mine the usual method of kiln-drying, dry-crushing and subsequent cyaniding, for which the plant had been spe- cially designed, was the system in vogue ; but while the ex- traction was high, the working-costs were heavy; and the treatment, though applicable to the oxidized surface-ores, was not suited to those of deeper levels. The ore being, moreover, of low grade, a change of treatment became imperative. The experiments here described were consequently made after such alterations in the plant as were necessary and practicable.

The choice of a satisfactory process depended on the suc- cessful treatment of the slimes, which formed a large propor- tion of the crushed ore, and, as was subsequently discovered, also contained the larger part of the total value. The use of lime, successfully introduced on the Rand by Mr. Williams, was found to satisfy this condition ; and the results, in view of the somewhat refractory nature of the ore, are interesting.

Nature of the Ore, — The ore is an extremely hard, flinty, bluish quartz, intermixed with finely-divided iron pyrites, the gold-contents being pretty uniformly distributed in an exces- sively fine state of division, and silver being present as sul- phide. Analysis showed the quartz to contain 5 per cent, of iron pyrites, with traces of calcium and manganese, the aver- age value being from 6 to 8 dwt. of gold and about 1 oz. 15 dwt. of silver per ton of 2240 lbs. The high cost for shoes and dies, as shown below in the table of working-expenses, will convey some idea of the very hard nature of the ore, which, owing to the fine state of division of the gold, had to be crushed through a 40-mesh screen in order to secure an ade- quate extraction. A prolonged amalgamation-test on a large amount of ore gave a very small percentage of the total bul- lion-contents. This being the case, and the ore carrying no visible gold, all attempts at amalgamation were discarded.

The association of the gold- and silver-contents with the mineral sulphides of the ore is shown by the two following ex- periments :

A. Blanketings weighing 72 lbs., obtained from 7.5 tons of ore, and crushed through a 40-me8h screen, assayed as follows per ton :

The Direct Cyaniding Of Wbt-Crushbd Ores. 127

Oz. Dwt. Gr.

Gold, 1 11 0

aWer, 3 8 14

B. Clean mineral, obtained from the concentration of a large tonnage of slimes in the main slimes-launder, assayed as follows per ton :

Oz. Dwt. Gr.

Gold, 4 18 0

SUvep, 10 12 8

This raised the question whether concentration would be necessary; but after experiments, both in the laboratory and on a working-scale, it was decided to classify the pulp into two classes only, namely, sands and slimes.

The largest proportion of the mineral sulphides in the ore crashed to slimes. This accounts for the higher value of the bullion-contents of the slimes as compared with the sands.

After cyanide treatment of the sands, average samples of clean mineral, obtained by concentration from the residues, assayed as follows per ton :

Oz. Dwt. Gr.

Gold 0 4 21

Silver, 1 6 2

This shows a high extraction from the contained mineral sul- phides. In experimenting on the mineral concentrates in the laboratory, it was not found possible, even by using a solution of higher strength, to get the residues below 4 dwt. per ton in gold without first crushing them finer.

With reference to the mineral-contents of the slimes, one of the initial difiBculties was the tendency of the mineral sulphides to separate out during agitation and settle on the bottom of the vat These assayed as follows per ton :

Before treatment :

Oz. Dwt Gr.

Gold, 1 7 18

SUrcr 5 9 10

After treatment :

Gold, 0 9 18

Sflrer, 2 17 4

Experiments showed that the poor extraction was due to want of proper agitation. It is essential that the agitators be

128 The Direct Cyaniding Of Wet-Crushed Ores.

SO constructed that when in motion they will sweep the bottom of the vat perfectly clean. The agitator adopted consists of a central revolving shaft, which can be raised or lowered as re- quired, and carries two parallel fixed wooden arms, set 3 ft. apart, the lower arm reaching within 9 in. of the bottom of the vat. Holes are bored through the arms at regular intervals of 6 in., and wire-rope (some old |-in. aerial cable being used), cut into 5.5-ft. lengths, was passed through them and keyed into position, the ends next the bottom of the vat being teased out so as to act as a sweeper.

This was an effective agitator. The assays of the mineral- ized portion of the slime-residues, in two successive charges, were as follows per ton :

Charge No. 1 :

Oz. Dwt. Gr.

Gold, 0 2 10

Silver, 1 6 2

Charge Xo. 2 :

Gold, 0 2 0

Silver, 1 2 10

These results show a good extraction from the contained sulphides.

General Description of the Treatment. — The mortar-boxes, which had the double discharge for dry-crushing, were altered to single discharge for wet>crushing; but even after this change were obviously unsuited to the work. This fact, no doubt, in- creased the percentage of slimes ; but it was found in actual practice much easier to get a good extraction from the slimes than from the sands. A number of sizing-tests on the sand- residues showed that the greater part of the gold which they retained was in finely-divided form in the coarser quartz parti- cles.

. The ore was crushed through a 40-mesh screen. The clas- sification of 656 tons crushed gave 355 tons, or 54.11 per cent., of sand, and 301 tons, or 45.89 per cent., of slimes. A sizing- test of the sands taken during this period is shown in the table on page 129.

It thus appears that, taking the sands and slimes together, 70 per cent, of the pulp, on an average, was crushed fine enough to pass through the 80-mesh sieve, this being the fine-

Thb Direct Ctakiding Of Wbt-Crushed Ores.

Mesh.

Per Cent.

Through.

On.

; 40

1 50

Loas

' 100.0

nesB, as determined by experiment, requisite for a good extrac- tion.

The crashed passed direct from the mill to a spUzkastenj 5 ft. square at the top, coming to a point 5 ft. deep, and pro- vided with a 2.5-in. cock at the apex to regulate the discharge of the sand-pulp. A rose, connected with a 1.5-in. high-pres- sure pipe, passing down the center of the spitzkdsteriy reaches to within a few inches of the bottom. The inclined sides only of the rose are perforated. When the spitzkasten is at work, this throws an upward spray of water under pressure.

The success of the treatment depends largely on good clas- eification, since any slimes carried over with the sands are apt to be lost in the overflow from the sand-vats ; while, on the other hand, any fine sands present in the slimes will cause a portion of the slime-pulp to set hard at the bottom of the vat, in a mass too tough to be affected by the agitator. There is in this case a consequent loss in the ultimate cyaniding through non-treatment. It was only on the addition of the rose to the spitzkasten that a satisfactory separation was obtained.

The resulting products were treated quite separately. The discharge from the spitzkasten passed to a sand-vat, where it was discharged through a Butters distributor ; and the over- flow of the spitzkasten constituting the corresponding slime- charge, passed to one of the agitator-vats.

Treatment of the Sands.

The average charge was 80 tons, the vats being circular, 20 ft- in diameter and 4 ft. deep. The sands were treated in the

Toi* . — 9

180 The Direct Ctaniding Of Wet-Crushed Ores.

ordinary way, after a preliminary alkaline wash according to requirements, followed by a wash from the "No. 2 weak" sump, in order to reduce the initial consumption of cyanide on the first contact of the strong solution with the ore. An 0.5- per-cent. solution of cyanide for the dissolution of the gold- and silver-contents was followed by the usual washes from the strong and the weak sumps, with a final water-wash to displace the cyanide-solution. The sands being a perfectly clean, uni- formly leachable product, quite free from slimes, presented no special difficulties in treatment.

Treatment of the Slimes.

The slime-vats were circular, 22 ft. in diameter and 7 ft. deep, and the average charge (corresponding to a SO-ton charge of sands) was 25 tons of slimes per vat. The overflow from the spiizkasten being carefully run in at one end of the vat, the clear liquor was allowed to flow away at the other ; and when the vat had been charged, the slimes were allowed to settle, and the water was drained off by means of an inside siphon-pipe, leaving a pulp which contained, after draining, from 42 to 58 per cent, of dry slimes. The agitator was now started, being- at the same time gradually lowered. The value of the charge was ascertained by means of dip-samples, taken during agita- tion, which we found to give most accurately the value of the total bullion-contents. Lime was now added in sufficient quan- tity to coagulate the slimes (14 lbs. per ton of dry slimes being the average amount required), and the charge was agitated for an hour in order to neutralize the eftect of the free acid and other " cyanicides " present in the ore.

In order to economize cyanide, and prevent the volume of the sump-solutions from becoming unmanageable (our sump- accommodation, during these experiments, being limited), the amount of dry slimes and of water in the pulp was carefully estimated in the sample of the slimes-charge, and the required amount of cyanide, dissolved in 5 tons of No. 1 " strong sump,** was added, in order to bring up the total solution present in the charge to 0.16 per cent, of cyanide. This strength of solution, found in actual practice necessary for the effective solu- tion of the gold and silver, was higher than the preliminary laboratory-experiments had indicated. These, however, were

Thb Direct Ctaniding Of Wet-Crushed Orbs. 131

not made under exactly similar conditions. The charge of slimes-pulp, which occupied a depth of from 3 ft. to 4 ft. in the vat, was now agitated at the rate of 40 revolutions per minute for 3 hours (the time necessary to obtain a satisfactory solution of the bullion-contents) ; solution from No. 1 strong slimes- sump was then pumped on, and agitation was continued until the slimes-charge was complete, the pulp now occupying a total depth of 6.5 ft. The agitator was now raised, and the slimes allowed to settle, after which decantation began.

The arrangement for drawing oft' the cyanide-liquors con- sisted of a 2-in. wired rubber hose, fixed inside the vat, and connected at the bottom and close to the side of the vat with the solution-pipe to the extractor-boxes. The end of the hose is held firmly in an iron xjoUar, to which is attached an arm of J-in. square iron. This arm passes through a guide, which can be moved freely along a 1 J by |-in. iron-bar, 3 ft. long, which is bolted to the inside edge of the top of the vat. A thumb- screw through the guide holds the arm in position; and, as the hose is lowered, the guide can be moved along the fixed iron- bar and the arm securely clamped. When not in use, the arm is raised and clamped, and the hose, being drawn up close to the side of the vat, is clear of the agitator.

Since there was no intermediate storage-tank, and the solu- tions had to be drawn off direct from the vats to the extrac- tor-boxes, this was found to be the safest arrangement. Care was taken not to set the mouth of the hose too close to the level of the slimes, as on draining off, the pressure of the top solution being removed, they rise. Automatic floats were found nnsatisfactory, as they were both difficult to adjust and required a considerable amount of watching; while, with the arrange- ment described, once the hose-pipe is properly set, it only re- quires lowering occasionally, and there is no risk that slimes will pass along with the liquors into the extractor-boxes. After drawing off the first wash, agitation with sump-solutions, fol- lowed by decantation, was continued, until a satisfactory ex- traction was obtained. Additional lime was added, if required ; but the preliminary coagulation was usually suflicient.

From four to eight washes were required, according to the size of the charge and the nature of the slimes-pulp, which was at some times more bulky than at others. The total weight of

The Direct Cyaniding Of Wet-Crushbd Ores.

the washes required was from three to four times that of dry slimes present in the charge.

Each wash was in every case passed through the extractor- boxes before being returned to the slimes-vats. The precipita- tion was satisfactory even in the most dilute solutions. The rate of flow through the extractors was regulated to 2 tons of solution per hour per cub. ft. of zinc-shavings.

The following is a summary of the results obtained during the experiments, on a working-scale, upon 1440 tons of differ- ent classes of ore, taken from the mineralized portion of the reef at the lower levels.

Summary of Working Results. Report No. 1.

During the period from August 27 to October 4, 1900, quartz from the north end of the Low level only was crushed, the ore being, as already described, extremely hard, and con- taining 5 per cent, of finely-divided iron pyrites. The amount of ore crushed was 656.1 tons.

Classification : The separation by the spiizkasten was as fol- lows :

355 tons passed to the sands-yats 54. II per cent.

301.1 '' 656.1 tons.

slimes- " =45.8

The total gold was divided as follows: in the sands, 46.9 per cent. ; in the slimes, 53.1 per cent.

Of the total silver, 41.28 per cent, was in the sands and 58.72 per cent, in the slimes.

Extraction. — The following tables show the extraction :

Gold.

Tons To

of

2240 lbs. 0.

tal Gold.

Gold Per Ton.

Percent- age

Dwt.

Or.

Oz. Dwt. I Gr. Oz.

Dwt.i Gr.

8 ! 13 1 18

10 ! ;

Oz. Dwt. Gr. 1 10

; 1 1 s

1 1 7

ExtTHC-

tion.

Sands 355 107

SUmes 801.1 121

6 1 25 8 1 2 17

6 23 42

86.0&

Total 656.1 229

Thb Bib.Bct Cyaniding Of Wet-Crushed Ores. 133

Silver,

Tons Total Silver.

Percent- Extrac- tion.

22401bs.

Oz. Dwt.| Gr.

Oz. Dwt.

1 6

Or.

Oz.

Dwt.

Or. Oz.

8 , 1

Dwt.l Gr.

Sands.

- 355 1 477 12 I 8

- 301.1 I 6f79 8 I 22

ToUL

.. 656.1 |ll56: 16 6

1 ' 15

Working- Casts. — The working-costs for milling and cyaniding are included in the cost-sheet for the total 1440 tons treated.

Beport iVo. 2.

During the period from October 4 to November 22, 1900, two differeut classes of ore were crushed, namely :

L 467.9 tons from the north end of the Low level, the na- ture of the ore being similar to that dealt with in the last re- port, and having an average value of £1 105. lOrf. per ton.

(Jassijication :

245 tons passed to the sands-vats 52.34 per cent. 222.9 " slimes- " 47.66 "

n. 315.9 tons from the south end of the Low level, the na- ture of the ore being much softer, more mineralized, and show- ing a greater tendency to crush to slimes, and having an aver- age value of £2 Ss. 9d. per ton.

Classification :

148 tons passed to the sands- vats 46.86 per cent. 167.9 " " slimes- =63.14 "

The classification for the total 783.8 tons of ore crushed was as follows :

393 tons passed to the sands-vats 50.26 per cent. 390.8 " " slimes- =49.74

783.8 tons.

Of the total gold, 46.9 per cent was in the sands and 68.1 per cent in the slimes.

Of the total silver, 88.8 per cent, was in the sands and 61.2 cent in the slimes.

Eriraction. — The following tables show the extraction :

Thb Direct Ctaniding Of Wet-Crushed Ores.

Gold.

Tons

of

2240 lbs.

Total Gold.

Gold Per Ton.

Gold in Resi- dues.

Gold Per Ton.

Percent- 1

Os.

Dwt.

Gr. Oz.

Dwt

Gr.

Oz.

Dwt.

Gr.

Oz.

Dwt.

Gr.

Extrac- tion.

Sands

. Slimes

135' 9

75.1 .

Total

Silver.

Tons of

Silver Per Ton.

Percent- 1

Extrac- tion.

2240 lbs.

! 1 1 Dwt. Gr. Oz. Dwt. Gr.

Oz.

Dwt.

Gr.

Oz.

Dwt.' Gr.

14 1 19 6 9

Sands

Slimes

6 ; 18 2 1 18

14 ' 15

Total

It will be noticed that the extraction during this period was lower than that shown in Report No. 1. In the ce of the sands, this was found to be due to the retention of a larger proportion of the gold in the coarser quartz particles, owing to the richer nature of the ore from the south end. In the case of the slimes, the unexpectedly increased quantity to be dealt with, and the more highly mineralized nature of the ore, made this product more difficult to treat. The lower extraction of silver, which is intimately associated with the contained min- eral sulphides, as compared with the sands-extraction, was due to imperfect agitation, owing to the increased amount of slimes produced from the south-end ore, which contained a greater proportion of associated mineral sulphides.

The crushed ore was sampled before entering the spitzkasten as a check against the sands- and slimes-samples. All the sands- and headings-samples were ground in a Park-Lacy fine crusher to an impalpable powder before asay. The final clean- up showed the actual bullion yield to be about 3 per cent, lower than that indicated by assay.

Working-Costs. — The working-costs for both periods under review, during which a total of 1440 tons of ore were treated, are embodied in the following table. Water-power is in use

The Bikect Cyaniding Of Wbt-Crushbd Ores.

at this mill, but owing to a shortage, due to dry weather, the item for wages is higher than would otherwise have heen the case; because, during a part of the time, it was possible to run only 10 stamps out of the total number of 20 which had been altered for wet-crushing.

Cost of Treatment of 1440 Tons of Ore.

'Cyanide, 2.7 lbs. per ton..

Zinc, .76 " " " ..

Cansticsoda, .76 " .. j Lime, 7 " " ..

! Milling and cyaniding wages..

Filter cloths

Screens

I Shoes and dies Oils Assaying and melting Manament

Snndnes, including royalty

Total cost per ton of 2240 lbs..

8. d. 3

Oi

7J

The necessity of using stronger solutions, owing to the na- ture of the ore, and in order to obtain an adequate extraction of the silver (which is an important part of the total bullion value), makes the consumption of cyanide on these ores a good deal higher than the general average.

Conclusions.

In view of the foregoing results, it is doubtful if the higher extraction which could be obtained by concentrating out and treating separately the mineral sulphides from both sands and climes would compensate for the extra working-costs which such a treatment would involve — to say nothing of the initial expenditure which would be necessary. Otherwise, this would seem at first sight to be the ideal method of treating such an ore. Several of the mills here crush with a cyanide-solution of about 0.1 per cent., thus obtaining a rapid solution of the bullion-contents during crushing, sometimes amounting to as mach as 60 per cent, of the total value of the ore ; but owing to the difficulty of preventing a large consumption of cyanide when the ore is mineralized, this method of treatment was not tried in the case here discussed.

136 Trbatmbnt Op Zinc-Peboipitatb Obtainbd In Ctaniding.

Notes on the Treatment of Zinc-Precipitate Obtained in Cyaniding Nev Zealand Ore.

BY HAMILTON WINGATE, B.SC, AUCKLAND, N. Z. (New Haven Meeting, October, 1902.)

In view of the fact that the fineness of the resultant bullion varies with the particular treatment to which the zinc-precipi- tate is subjected, and since there are considerable losses attrib- uted to both methods, the following notes on the results obtained at the Waitekauri Extended mine, Maratoto, N. Z., may be of interest.

The ordinary method of roasting the vacuum-dried precipitate was adopted instead of the treatment with sulphuric acid, the necessary facilities for the latter method not being available. Moreover, provided the ordinary method is carried out with the necessary care, it is questionable if it is not the most satis- factory where large quantities of precipitate have to be handled, and where (as is generally the case in this district) a consider- able amount of silver is present.

All the precipitate was first washed through a 40-me8h sieve. If it was necessary to recover the bullion at once from the ac- cumulated short zinc, it was oxidized and melted separately ; but, as a general rule, being heavily charged with bullion, it was placed on the bottom of the trays at the top end of the ex- tractor-boxes, where it acted as an excellent precipitant, the bullion being recovered at the next clean-up.

After drying on a filter with the aid of a vacuum-pump, the precipitate was weighed and removed to the oxidizing fur- nace, which is similar to that generally in use in New Zealand, consisting essentially of an ordinary square tray of cast-iron, with 6-in. sides, built over a brick furnace. Wood is used as fuel. The tray is hooded over with sheet-iron, fitted with a sliding- door, and the fumes pass through a flue at the top into a dust-chamber, then into the open air.

Oxidation of the Precipitate. — The oxidation was conducted first at a low temperature, which was gradually raised, until

t&SATMSKT OF ZIKC-PRBCIPITATB OBTAINED IN CYANIDINQ. 187

finally the iron tray was at a very dull-red heat, the precipitate being kept broken up with a suitable rake, and great care being exercised to avoid loss by dusting, especially as the last stage was reached. After cooling, the precipitate was carefully weighed, the time occupied in oxidizing being from two to four hoors.

Mdting of the Oxidized Precipitate. — The oxidized precipitate was fluxed as follows : 100 parts of oxidized precipitate ; 50 parts of anhydrous borax; 15 parts of anhydrous sodic carbon- ate ; and, after mixing, carefully charged into a No. 50 plum- bago cruciblCyand melted at a moderate heat, the pot being kept carefully covered during ftision, and recharged in each case before ftision was quite complete. When three-quarters fiiU, the temperature was raised, the slag, now thoroughly liquid, was ladled off into moulds, and the crucible recharged as before, until about two-thirds full of molten bullion.

The bullion was now poured into moulds, each bar being again melted in a crucible of smaller size, an skimmed, if necessary, before pouring. After washing, the bars were then sampled and weighed.

The following table gives the particulars of eight consecu- tive clean-ups, and the fineness of bullion obtained :

Xo. Weight of

of Vacm. Dried

MelL Precipitate.

LfasAToir.

I Percent. WttiirKfrif ' Yield of

Precipitate.

Lbs. AToir.

TouL 833 I 466.25

Bnllion from Oxi- dized Pre- cipitate.

Total

Weight of

Bullion

Obtained.

Fine Gold j Fine Silver; Contained Contained in Bullion. I in Bullion.

Oz. Troy.

Oz. Troy.

3710.70 807.60

'Fineness of

Bullion

PerlOOO

Parts in

Gold and

Silver.

Oz. Troy.

XoTE. — In the case of Nos. 1, 8, 5 and 7 only the top par- titions of the extractor-boxes, containing the most of the pre- cipitate, were cleaned out, whilst in the case of Nos. 2, 4, 6 and S a complete clean-up of the extractor-boxes was made. The

138 Cost Op Hydeaulic Mining In California.

bullion was recovered from ore all of which had been wet- crushed.

The fineness of the bullion obtained was mainly due to the passing of the precipitate through the 40-me8h sieve, thus elimi- nating the " short zinc." It is impossible to oxidize such zinc, scattered throughout a mass of bulky precipitate. Its presence causes both mechanical losses and losses through volatiliza- tion, and it is most important that it be either eliminated or oxidized, if subsequent losses in melting are to be avoided.

Sampling of the Bars. — The bars so obtained were of very uniform composition, and the drillings from a hole right through the bar gave very accurately its actual value. The base metals present were zinc, together with lead, iron and copper, in small quantities, the latter being derived most prob- ably from the fulminate-caps used in the mine, as no trace could be detected of its presence in the ore.

SlagSy Etc. — These were crushed in the mill, giving a return equal to IJ cent, of the total bullion recovered, the tail- ings, as bagged for shipment to the smelter, being worth, ac- cording to careful sampling, £25 per ton. The sweepings from the dust-chamber and flue resulted in the recovery of bullion of a total value of £9 after the oxidizing of some £6000 worth of precipitate, showing the loss from this source to have been small.

Notes on the Cost of Hydraulic Mining in California.

BY W. E. THORNB, GEORGETOWN, CAL. (New York and Philadelphia Meeting, Febraary and May. 1902.)

In his paper on the hydraulic mining of a low-grade gravel in California,* Mr. W. H. Radford expresses the hope that other members of the Institute will contribute, for the benefit of all, their experience in similar lines. In these notes I shall describe the conditions and results of the operation of the Gold Bug Mining Co., of Cleveland, 0., at Georgetown, Eldorado county, Cal,

2VofM., mi., 617.

Cost Of Hydraulic Mining In California. 13

This district drains into the American and Sacramento rivers, and is thus subject to the U. S. Debris Commission, which requires from every hydraulic mine the building of a dam to impound the tailings.

The property of the company lies in a narrow canon, 1 J m. long, with an average width of 200 ft, and a maximum depth, at the upper end, of 23, and a minimum depth, at the lower end, of 7 fl- This difference of depth is due to the existence, at the upper end", of " seam-diggings,'' which have been depos- iting their tailings in the canon for the past 50 years. These tailings have been carried down and scattered over our ground by every freshet, until, at the present time, they constitute about 60 per cent, of our gravel.

The ground is worked through bed-rock sluices, mostly 8 ft. wide on the bottom, and laid in a cut having at the lower end the maximum depth of 25, and at the upper end the minimum depth of 4.5 ft. At the lower end, each 12-ft. box has a fall of 4 in. ; at the upper end, the fall is but 1 in. per 12-ft. box. There is 1300 ft. of the 8-ft. sluice and 200 ft. of 4-ft. sluice, making a total of 1500 ft. of bed-rock sluice.

The mud-sills at the head of each box, 6 by 6 in. in size, are held in place by a drifl>-pin of in. round iron, driven into bed- rock horizontally, at each end. The intermediate mud-sills are 4 by 6 in. pieces, placed on edge, and held in the same way as the end-sills. The bottom is of 2 by 12 in. stuff, with a center-board 1.5 by 18 in., placed on edge, so that at low water one side will carry the water while the other is being cleaned up.

The sides, 36 in. high, are made up of two 1.5 by 18 in. boards on each side, and have a batter of 1 in. in 6 in., making the sluice 1 ft. wider at top than at bottom. The sluices are paved with 6 in. blocks, set on end.

This construction cost from (4 to $150 per linear foot. Hand- drilling in hard diorite, which constituted a part of the forma- tion at the lower end, was the cause of the maximum cost. Most of the cut is through Mariposa and Calaveras slates.

Our grade became so light (1 in. to 12 ft.) at the upper end that we liad to depend on the maximum flow of the creek (about 3000 miners' inches, which continues for only about 15 days in the year) for our sluice-head. Our head for the Giant

140 Cost Of Hydraulic Mining In California.

we obtained, at a cost of 0.5 cent per hour per miners' inch, from a ditch owned by another company. "We used, through a 3-in. nozzle, 200 miners' inches, under a head of 180 ft. Our average of material moved was 43.5 cub. yd. per hour — a very low duty, due to our working up-stream.

The value saved per yard, and other data of that kind, I am not at liberty to give. Such particulars, belonging to the pri- vate business of a given company, and involving, as a factor, the value of its mining ground, has really little or no technical value. It may satisfy curiosity, but it does not benefit science or practice. The percentage of recovery or loss, calculated upon trustworthy sample-assays of the crude material, would be, indeed, valuable as a guide to possible improvements in ap- paratus or operation. But such a calculation is not practicable in hydraulic mining. I give, therefore, all that I have which seems likely to be useful, namely, a statement of the working- costs, so classified as to permit comparison, item by item, with those of similar enterprises.

Working-Costs per Cubic Yard of Material Hydraulically Moved.

Water, $0,030

Labor, 0.015

Debris dams,* 0.030

Moving of pipe, etc., 0.005

" Crevicing " and cleaning bed-rock, 0.006

Taxes, salaries, etc,t 0.007

Blacksmithing, 0.003

Lumber, 0.030

Labor on sluices, 0.040

Powder, fuse, etc., 0.017

Total, $0,183

Our supplies, delivered at the mine, cost as follows : Lum- ber (rough), $14 to $16 per M.; powder, 12 to 13 cts. per lb. in ton-lots; fuse (triple tape), by the case, 50 to 55 cts. per 100; caps (N'o. XXX.), 60 to 65 cts. per 100; round iron (J in. diam.), 8.5 cts. per lb.; nails (cut and wire, by the keg), 3.5

This item represents the total cost of such work, divided by the total capa- city in tons of the reservoirs thus created.

t This item is exceptionally large, because of the short season of 15 days, upon which the calculation is based, and the consequently small amount (7500 cu. yds. ) of material moved. The other items are more nearly a fair average ; though, of course, the short season of operation had in many ways an indirectly unfavorable effect on costs.

Cost Of Hydraulic Mining In California. 141

to 4.5 cts. per lb. The wages of miners were $2.50 per day of 10 hours.

The method above described was in operation when I took charge of the mine ; and, to my request for permission to sub- stitute a dredge or hydraulic elevator, it was replied that as the existing system had been installed under the advice of expe- rienced placer-miners, I must give it a trial. The result, as the statement of cost might lead an expert to expect, was not eco- nomically satisfactory; and we are now installing a hydraulic elevator, of which I hope to have something to say in the near future.

Two under-currents were tried. No. 1 was placed about 700 ft. below the lower end of the bed-rock sluice. (It should have been at the sluice and connected with it.) It cost about |1500, and saved about enough gold to pay the taxes and in- terest on that investment, together with the cost of cleaning it up. No. 2, placed 1500 ft. below the lower end of the bed-rock sluice, cost $1700, and has never caught enough gold to pay the cost of cleaning.

I have ven the foregoing statement, showing our maximum costs, as a companion-piece to Mr. Radford's notes, in order that those who contemplate investments in hydraulic mining may not be led to believe that all enterprises of that kind can be operated as cheaply as the one of which he writes.

In the instance here described the company was misled, by reports of exceptional cases, into the belief that this property, like others of which they had read, could be handled with Giants and ground-sluices at very low cost. As the foregoing statement shows, the costs turned out, on the contrary, to be very high.

Mr. Radford's opinion that, " under fairly favorable condi- tions gravel of quite low grade can be worked at a profit," calls for a further definition of what would constitute fairly favor- able conditions." According to my knowledge of hydraulic mining in California, one of these conditions must necessarily be that the property must lie outside of the drainage-basin of the Sacramento; for, within that area, the cost of the required impounding dams alone would almost equal the value of the gravel he describes.

Most men write of their successes only. Why not, once in a while, tell of a failure, as I have here done ?

142 Calculation Op Weight Of Castings With Planimetbr.

The Calculation of the Weight of Castings- with the Aid of the Planimeter.

BY C. M. 8CHWERIN, E.M., CHICAGO, ILL. (New York and Philadelphia Meeting. February and May. 1902.)

The object of this graphic method is to estimate the weight of the casting, which is to be made from a given pattern, -when the cross-section is not a uniform geometrical figure. Such an estimate is a very important guide to the foundryman, who would otherwise guess at the probable weight of a casting of new design, and, in trying to be on the safe side, would proba- bly melt an unnecessary amount of iron. It is also an aid to the designer of a new car-wheel pattern, who must otherwise estimate from general experience the probable weight, have test-wheels made, and correct the pattern afterwards, so as to obtain the weight prescribed.

For the method here described, an accurate drawing of the pattern is employed. This gives a closer result than a drawing of the wheel itself, for the following reasons :

1. Calculations based upon the actual dimensions of the wheel involve the erroneous assumption that the specific gravity of the casting is uniform throughout ; and upon that basis the calculated weight would be wrong, because the amount of metal poured has shrunk in the mould, acquiring the highest density in the outside chilled portion, and growing less dense through the mottled to the gray portions.

2. Calculations based upon the dimensions of the pattern or " chiller " assume that the cooled metal will not have shrunk, but will have the volume of the pattern and a uniform density.

These assumptions, though erroneous, counterbalance ea<5h other. For instance, the patterns and the chiller which give a wheel 33 in. in diameter when cold, are respectively 88.5 in. in diameter. This shows a shrinkage for wheel-iron of about A in. (ordinary gray pig is commonly assumed to shrink about J in.) per foot. Wheels cast in 33.5-in. chillers do not always have the

Calculation Of Weight Op Castings With Planimbtbr. 143

same diameter. They may vary J in. either way by reason of differences in composition, pouring-temperature, duration of pouring, and probably also slight variations in cooling. But the average diameter is 33 in. ; and it is found that a calcu- lation based upon the 38.5-in. pattern, and the assumed uni- form density of 0.26 lb. per cub. in. of molten wheel-iron, as it fills the mould, gives correct weights of the wheels, even though the latter vary in size, as before explained.

For a casting of uniform specific gravity, either the draw- ing of the casting, or that of the pattern, could be used. If the latter, then a percentage for shrinkage must be sub- tracted.

Fig. 1 shows, in reduced size, half the cross-section of the pattern of an ordinary cast-iron car-wheel. From the fuU-

FlG. 1.

CzoaB-Section of Half the Pattern. L M N, Cross-section of pan-core. G H P, CroaB-aecdon of bracket. E F C D, Cross-section of plates, tread and flange. J P K, Top of brackets. J K, Circle of flange. C V, Circle of rim. O O, Center-line of wheel axis.

sized drawing, divided as shown in the figure, the areas A B C D and E F B A are taken with the planimeter, and the area L M N, similarly determined, is subtracted from their sum. The remainder is the area of the half-section of the pat- tern, exclusive of the brackets. Let this area (in sq. in.) be called A.

A blue-print is then made pasted on card-board, cut out along the lines D E F C D and L M N L, and then balanced on a pin-pomt, to determine the center of gravity of the irregular figure. This point (o in Fig. 1) is located on the tracing, and its distance from the center-line of the wheel-axis, 0 0, is meas- ured. Let this distance (in inches) be R. If w (0.26 lb.) be taken as the weight of the metal per cub. in., and W as the

144 OAiiCULATION OP WEIGHT OF CASTINGS WITH PLANIMETER.

weight of the wheel, then W=2?rRxAxw + weight of brackets and letters, minus weight of metal displaced by the core-legs of the pan-core.

The following calculation for two wheels is given as an example :

The calculation for 2 7t R X A X w was as follows :

No.1. No. 2.

Area of EF CD, 2.38 gq. in. 53.17 sq. in.

Area of L M N, . . . . 12.42 sq. in. 9.60 sq. in.

Net area (A), . . . . 39.96 sq. in. 43.57 sq, in.

B, - 9.38 in. 9.25 in.

Cubiccontent8ofpattern23rRXA, 2853.6 cub. in. 2531 cnb. in.

Weight (cub. cont X 0.26), . . 61 1.95 lbs. 658 lbs.

! n.

The requisite addition for weight of brackets is approxi- mately calculated as follows :

No.i.

No. 2.

Area,GPH, . . . .

2.24 sq. in.

2.30 sq. in.

Assumed average, J G P H, .

1.12 sq. in.

1.15 sq. in.

Average length, measured on curve.

10.5 in.

10.25 in.

Volume of one bracket,

11.8 cub. in.

11.8 cub. in.

Weight (vol. X 0.26), .

3.06 lbs.

3.06 lbs.

Weight of 13 brackets, .

39.78 lbs.

Weight of 15 brackets, .

45.9 lbs.

Note.— The 660-lb. wheels have 13, and the 700-lb. wheels, 15 brackets.

m.

The weight of the letters was obtained by weighing the same letters cast in lead, and taking seven-tenths of the result as correct for iron. This gave, for each wheel, 1.2 lbs.

The amount to be subtracted for the metal displaced by the core-legs was calculated as follows :

Thickness (x y) of bottom plate, . Approx. av. diam. of core-legs, . Area of base of equiv. cylinder, . Volume of equiv. cylinder, . Weight (vol. X 0.26) for 1 core-leg. Weight (vol. X 0.26) for 3 core-legs,

No. 1.

No. 2.

Hin.

lA in.

4.4 sq. in.

5.9 sq. in.

4 cub. in.

6.5 cub. in.

lib.

1.7 lbs.

3 lbs.

5.1 lbs.

Determining The Size Of Hoisting-Plants. 145

The final net weight for each wheel was determined as fol- lows:

Xo. 1. 611.95 + 39.78-1-1.2 — 3 =649.931bfl.

No. 2. 668 + 45.9 + 1.2 — 5.1 700.00 lbs.

The calculation for No. 1 was made from the pattern-draw- ing for a 650-lb. wheel ; that for No. 2 from the pattern-draw- ing for a 700-lb. wheel. The cleaned wheels made from these patterns are averaging 655 and from 700 to 705 lbs. respectively.

Since a variation of 2 per cent, above or below the regular weight can be easily caused by variable moulding in the mak- ing of a car-wheel, it will be seen that the foregoing method of calculation gives reliable results. For castings of soft iron, and of more regular shape than car-wheels, even better results oould be obtained.

Determining the Size of Hoisting-Plants.

BY EDWARD B. DURHAM, E.M., TRENTON, N. J. (New York and Philadelphia Meeting. February and May, 1902.)

It is often necessary to calculate the size of a hoisting-plant required to raise a given quantity of material, either as a pre- liminary to' the detail design of the machinery, or to decide whether machinery on hand or offered by a manufacturer is adapted to the work to be done.

The first element of the problem to be determined is the load to be raised. In a mine that is already developed, this is limited by the size of car that can be hoisted out of the mine and that will pass through the underground gangways. If these place no limits on the design, the size of the load will legend on the output desired per day, and on the number of hoists that can be made per day. The latter are fixed by the time required per hoist and the number of hours available for boiting, after deducting from the working-day the time re- quired for raising and lowering men, sending down supplies, and for the many small delays in handling cars. It mast also Uf decided whether the hoisting is to be done in one shift or in afl of them.

VOL. XXXill. — 10

146 Determining The Size Of Hoisting-Plants.

As an example, assume an output of 400 tons per 10 hours : shaft, with two compartments, 1000 ft. deep; hoisting in bal- ance ; time available for hoisting, 6 h. ; engine can hoist load in 1.5 min., and time to change cars 0.5 min. (the change at top and bottom of shaft being made at the same time). Then, 30 cars can be raised per hour, or 180 cars in 6 hours. This would require cars of 400 180 2.22 tons capacity, to handle the desired output.

With a single shaft, the time to raise one load is the time to change or load cars at the bottom, hoist loads, change cars or dump at the top, and lower the empty cars ; while, in a double shaft, two cars could be handled while the above programme was being carried out in a single shaft, as the second load would be raised while the first empty was going back down, and changing of cars at the top and bottom would be going on simultaneously.

Ropes. — Having settled the size of the useful load to be hoisted, the size of the rope must be determined. This must be strong enough to hoist the total load, including its own weight, and to withstand the starting-stresses due to picking up the load suddenly when the rope is slack. Experiments have shown that, in starting with six inches of slack rope, the stress in the rope is about double that due to picking up the load gently.

Expressing these stresses in a formula, let

K stress in rope in pounds, at the head sheave, at the in- stant of picking up the load.

W weight of gross load in pounds.

E weight of rope in pounds.

F friction in pounds weight of all moving parts mul- tiplied by f.

f coefficient of friction.

Then K 2 W+ R + P. (1) ,

This stress should not exceed of the ultimate strength of the rope. The coefficient of friction, f, may be taken as .01 for vertical shafts, and as .02 to .04 for inclined shafts with rope well supported on rollers.

As an example, required to find size of rope necessary to hoist a total load of 5000 lbs. from a vertical shaft 1500 ft. deep. Assume, for a trial solution, that rope weighs 2 lbs. per

Determining The Size Of Hoisting-Plants. 147

ft. From equation 1, K=5000 lbs. X 2 + 1500 X 2 lbs. + .01 X 8000 lbs. 13,080 lbs., and ultimate strength of rope should be 7 X 13,080 91,560 lbs., which would require a 1 J-inch- diameter flexible cast-steel rope, having an ultimate strength of 100,000 lbs., and weighing 2.45 lbs. per ft. This weight would increase R in above equation, and make 7 x K 96,285, which is still less than the ultimate strength of the rope chosen. If a rope of lighter weight is desired, a plow-steel rope could be used instead of the cast-steel.

If the shaft is inclined, the stress in the rope due to the weight hoisted will vary with the sine of the angle of inclina- tion, thus :

(2 W + R) sin a: + F, (2)

in which x is the angle of inclination. Here the friction is also aftected by the slope, and varies with the cosine of x, or F f (W-f R) cos X ; t may be taken as .02.

In the following discussion the loads will be considered as being hoisted from vertical shafts, as the principle remains the same for both classes, the only difference being that the stresses in the rope and on the engine and other parts of the machinery change with changes in the slope.

Drums. — The minimum diameter of the drums is determined by the size of the rope used, and the larger the drums the smaller will be the bending-stresses and the more strength will be available for useful work.

Mr. William Hewitt has shown that, when the diameter of the sheave or drum is 44.5 times the diameter of a 19-wire cast-steel rope, the bending-stresses are f and the remaining nseful strength is J of the maximum safe load " that the rope will carry. The " maximum safe load " is taken as J the ultimate strength. This is well below the elastic limit of the wire. Thus the available strength is only of the ultimate. In order to cut down the bending-stresses so as to leave of the ultimate strength of the rope available for useful work, the sheaves must be about 80 times the diameter of the rope. Other grades of rope require different diameter of drums, as will be seen by studying Tables I. and II.

Table 11. is based on the formula k , in which

2.06 + C

Determining The Size Of Hoisting-Plants.

Table I. — Hoisting-Ropes of 6 Strands of 19 Wires Each.

Iron.

Sap

f

156,000

124,000

96,000

72,000

62,000,

50,0001

34,000

26,000

18,600

11,000

8,800

6,800

5,000

3,400

2,400

62,000

41,333

82,000

28,000

24,000

20,667

16,667

14,000

11,333

8,667

6,467

3,667

2,933

2,267

1,667

1,133

Cast-Steel.

Extra Strong Cast-Steel.

Plow-SteeL

is

'

1;

4)

i

pproxlro Breakln in lbs.

s

I 312,000

1248,000

192,000

168,000

144,000 ;

124,000 ,

100,000!

84,000

68,000

52,000

88,800

22,000

17,600

13,600

10,000

6,800

4,800

104,000 82,667 56,000 41,333 38,383 28,000 22,667' 17,333 12,983 I 9,067 I 7,3331 5,867 4,583 2,267 , 1,600 I

361,000

288,000

224,000

194,000

168,000

144,000

116,000

98,000

60,000

31,600

25,400

20,200

15,600

11,560

8,100

5,400

F

£ n

-5

121,333

96,000

74,667

64,667

48,000

38,667

32,667

26.00U

20,000

14,667

10,583

8,467

6,783

5,200

2,700

1,800

330,000

256,000

192,000

164,000

184,000

112,000

88,000

68,000

50,000

29,000

17,700

13,100

St

If

138,667'

110,000

85,333

74,000 i;

64,0001

54.667 1.

44,667'

29,333 ;

22,667 ;

16,667

12,000;;

7,600

6.900;

4,367'

5h

'5,000 to

90,000 lbs.

150,000 to

200.000 lbs.

1 190,000 to

I 225,000 lbs.l

225.000 to

275.000 lbs.

k represents the bending-stress in pounds, E the modulus of elasticity 28,500,000, a the aggregate area of the wires in square inches, R the radius of the bend in inches, d the diain- eter of the individual wires in inches, and C a constant de- pending on the number of wires in the strand. The values of d and C are, for 19-wire hoisting-rope : diameter of rope, and 45.9.*

As an example, required the working-load of a 1-in. cast- steel rope running over a 6-ft. sheave. From Table 11. the bending-stress is found to be 9937 lbs., and from Table I. the " maximum safe stress " is found to be 22,667 lbs. The dif- ference, 12,730 lbs., is the working-load.

The size of the rope fixes the minimum diameter of the

Tables I. and II. were calculated by-r. William Hewitt, and are publislied here hj his permissioD. The originals, with other data on wire ropes, appeared in a pamphlet entitled Wire Hope and its Application to Power Transmission, " 1901, issued by Trenton Iron Co., Trenton, N. J., from whom copies can be ob- tained.

Determining The Size Op Hoisting-Plants.

Table II. — BrndingStresses of 19-wire Rope.

I>iam. of Bend.

6 I 8 10 I 12 14 16 18 20 22 24 26

Diam.of J4

Rope.

1.801 1,S90 1,131 965 3,308 2,568 2,098 1,774

3,776 '3,094 2,620

I 5,351 4,546

6,609

1,5361 1,355 2.273; 2,006 3,951 3,494 5,7551 5,096 8,337| 7,393! 11,56510,270 |l3,360!

"I"

1,212' 1,796 3,132j 4,573 6,642' 9,237i 12,027 15,309

1,096 1,626, 4,147 6,029 8,392 10,936 13,932 21,403

,000

,485

,594

,793

,519

,t5S9

,027; 9

,782111

,66218

366 1,265 389, 2,214 4951 3,241 089 4,721 095: 6,586 257 1 8,597 807:10,971 183116,910 612 25,707 35,620

DUm. of Bend.

28 I 30

S"

DiazD.ofRope.

1 "

%

I 2,06:?

4,4f>;-t ' 6,H5

ll5.S<i:i 24,04

1,102 924

1,31, l,e20

2,4i29 2,376

4ji5 3,4G8

9.609 SJOi; r'.]55

'J.:ll l<t,n;l 14,Ail4!

Ljo

:; I'sol

1 42,06 Sf.6?Ci'J7.lOOi 22

i J 4S.lim;iTj28 30,

, , Jl, 238 17,-29 38,

I ,... ..,. 7 J. -551 60,

88,

..! :i26,

1

270,

708;

1,212

1,042;

1,773

2,485

8,

977 4, 724 6, 830j 9 500, 13,

,257 ,173 ,481 937, 872'

239! 18

096 25,8501 21 -

436 1 32

152' 40

"I

,403

,6291 a.

,919l 41 ,3791 53 ,795' 61 ,265 9. ,24612

V"38 1,-76 -J, 159 :m53 in... 23 I m I:m72 :;'i.i03 IT. I -.39 SI . !28 lit.. -.46

1,1911

2,809

4,371 1

6,714

9,8871

12,682

22,030

27,6641

35,048

42,606!

51,160,

72,908

99,951

1,074

1,506

1,976

3,943

6,059

8,4741

11,452

15,545l

19,906

25,005

31,689

38,5341

46,285!

66,0021

90,540

Jrum, but questions of speed and length of drum also influ- ence the final choice of the diameter.

The maximum length of a drum, aside from question of room, is controlled by the allowable fleet-angle, that is, the acute angle included between two lines drawn from the ends of the drum to the head sheave. This angle should not exceed 3', in order that the rope may lead well on to the head sheave, and so that one rope will not grind or mount the next one in winding onto the drum. It is usual to place the drum far erjough back from the head sheave to keep the fleet-angle within the limit ; but where it cannot be done, it is necessary T. guide the rope onto the head sheave and onto the drum by rollers or sheaves running on vertical spindles. The bisectrix of the fleet-angle should strike the middle of the drum.

Tpes of Hoisting-Engines. — Single-cylinder engines are used in mining to replace man- or animal-power for light work.

150 Determining The Size Of Hoisting-Plants.

They are always geared and provided with a fly-wheel on the crank-shaft. They must be started to a fair speed, in order that the fly-wheel may develop suflicient momentum to carry the crank over the center, before the friction is thrown in to pick up the load. The cylinder should have 75 per cent, more power than is necessary simply to raise the load, in order that speed may be maintained.

Double-cylinder engines are used for all the regular work of mining. They may be divided into the following classes : I. Geared: — Single Cylindrical Drum. Double Cylindrical JDruia. Double Conical Drum. n. Direct Acting : — Single Cylindrical Drum.

Double Cylindrical Drum.

Double Conical Drum.

Koepe System.

Reels for flat rope. Each of these has a field of its own to which it is best adapted. Thus, the geared engine is used mostly for shallow depths and small outputs per day, while the direc1>acting engine is used where the output is large. There are many cases near the dividing-line in which either type of engine will give equally good results, and it is largely a matter of personal choice as to which is used.

Geared engines are made with small cylinders, and the engine proper runs at a speed of 100 to 200 r. p. m. The gearing usually gives a reduction of 'to so that the drum revolves at a moderate speed. The small cylinders make the first cost lower than that of a direct-acting engine ; but the gearing for large hoists is a serious objection. The main gear has about the same diameter as the drum, so as to keep the pressure on the teeth as low as possible; and hence it has a circumferential speed equal to the speed of hoisting. Gearing, under very favorable conditions, should not run at a speed over 1200 ft. per min., and with the large cast gears and the rough work to which hoisting-engines are subjected, the speed should probably not exceed 900 ft.per min. If the av- erage speed of hoisting is kept at about of this maximum, the average speed will not exceed 600 ft. per min. This speed will allow the use of moderate-sized drums and keep the piston- speeds within the limits of good practice.

Determining The Size Of Hoisting-Plants.*

That gearing ia liable to cause trouble and make consider- able noise when run at a high speed, has been forcibly impressed on the mind of the writer by his experience in charge of a geared hoister, made by a reliable manufacturer, having cylin- ders each 18 in. dia. by 24 in. stroke, and two drums, each 7 ft. 6 ia. dia. by 5 ft. face, on which three main gears, between 7 and 8 ft. dia., 3 in. pitch, and 9 in. face, were broken inside of nine months. The gears cost about $300 each, besides the labor of replacing and the loss of 24 hours in changing the old for a new

Fig. 1

Single Cylindrical Drum Engine

one. The engine was hoisting from a shaft 1000 ft. deep in about 1 J min. The load of ore was 2J tons.

Direct-acting engines should not be used for hoisting-speeds if less than 500 ft per min., as the piston-speed will be too slow for economy. They can readily be run at an average speed of 1500 ft. per min., and the largest engines can be run as much as 2500 ft. per min., if the shafts are deep.

Single-drum engines are limited to small outputs per day, or to places where the first cost of the plant is so important as to outweigh the loss in increased operating-expenses. This type

Bbtermining The Size Of Hoisting-Plants.

of engine has many applications, as for sinking winzes, and for other inside work ; also for shaft-sinking, and for working coal- mines on a small scale, where the cost of fuel is small, as waste material is burned. They are largely used in the Joplin, Mo., district, where the hoisting is from vertical shafts 100 ft. deep, the output often only 25 to 60 tons per day, and the ore is raised in buckets without guides, thus keeping the dead weight small, as compared with weight of ore raised. They are not adapted for regular mining work on a large scale, as the work

Fig. 2

Double Cylindrical Drum Engine

expended in raising the cage, car and rope, each trip, would ex- ceed the work of raising the ore.

Double-drum engines overcome the dead-work of hoisting the ore-carriers by balancing the weight of the cage and car in one compartment against those in the other. They are thus more economical to operate than a single-drum engine, and the cost of installing will probably not be over 50 per cent, greater than for a single-drum engine. The cost of sinking a shaft large enough for two hoisting-compartments and a manway is not much more than that of a shaft with only one hoisting-compart-

Detbrmining The Size Of Hoisting-Plants.

ment and a manway ; the head buildings must be nearly the same in either case; and the double-drum engine will have smaller eyKnders, thus partly offsetting the cost of the second drum.

With cylindrical drums, the ropes in the two compartments, from the cages to the head sheaves, are of constantly varying lengths, and are in balance only when the cages are passing at the center. With double conical drums, the work on the en- gine 18 kept constant by giving the cage at the bottom the short leverage of the small end of the drum, and the cage at the top the longer leverage of the large end of the drum.

The Koepe system, as applied to a double-compartment shaft, has a tail-rope passing from the bottom of one cage down and

Fig. 3

D-

Rl

Position A

Position B

c+o

c+o

Rl

Double Conical Drum Engine

around an idle sheave at the bottom of the shaft, and up to the other cage. Thus the weight of the rope in the two compart- ments is exactly equal, and the whole hoisting mechanism is in balance at all points of the trip.

The flat-rope system of hoisting attempts to equalize the work on the engine by coiling a rope of rectangular cross-sec- tion on a reel, like a surveyor's linen tape ; so that the diameter of the reel increases and the leverage of the load increases as the weight of the constantly shortening rope decreases. Thus the work on the engine is kept constant, when the rate of in- crease of leverage and decrease of weight are in inverse pro- portion to each other. The flat ropes, however, are heavier

Determining The Size Of Hoisting-Plants.

than round ropes of the same strength, are shorter-lived, and cost more at first and for subsequent care. The flat-rope sys- tem is very largely used in Montana, and in some other districts which have followed the Montana practice.

The peculiarities of the diflferent types of engines are brought out more fully by the calculation of the size of their cylinders when equipped with the different arrangements of drums.

Calculation of the Oylinders, — The maximum work on the en- gine is in picking up the load and in overcoming its inertia.

FiC. 4

Flat Rope Reel

At this time one crank may be on a dead center, so that all the work must be done by the other. At this part of the hoist, steam will be admitted for the full stroke and at its maximum th rottle-pressure.

Hoisting-engines belong to the slow-speed type of engines. Their valves are simple slide-valves in all but the largest sizes, and then they are usually of the Corliss class. They seldom have governing-devices, their speed being determined by the hoisting-engineer by means of the throttle, the link-motion and the brake.

Dbtermining The Size Op Hoisting-Plants. 155

With these classes of engines the piston-speed may be taken at 200 to 400 ft. per min. for engines of 12- to 24-in. stroke, and from 400 to 600 ft. per min. for those with 24- to 72-in. strokes. Very high-grade engines, with other valve-gearing, may run at higher piston-speeds.

At the instant of starting, the power in one cylinder acting on the crank, in the top or bottom position, must have a mo- ment equal to or greater than the moment of the unbalanced load pulling from the circumference of the drum. Aftier start- ing, the other cylinder comes in to accelerate the speed, and the two together are able to hoist the load with steam partially cut oflF and still maintain the full speed.

In all the following equations, let

W weight of unbalanced load in pounds.

C weight of cage and car, O weight of ore, and

R weight of rope, all in pounds.

D diameter of drum in feet.

P M E P mean eftective steam-pressure in cylinder in lbs. per sq. inch.

A area of cylinder in sq. inches.

L length of stroke in feet.

S speed of hoisting in ft. per min.

N" number of revolutions of engine per min.

F friction in pounds,

f coeflGlcient of friction.

r ratio of diameter of piston to length of stroke, both being

in feet or both in inches, - .

diameter

d diameter of piston in inches.

e efficiency of engine.

. diameter of gear

Then, for a single-drum, direct-acting engine. Fig. 1, the moment of the load (W + F) and the moment of the en- gine (P X A X e)— . Placing these equal to each other,

(W + F)D PxAxLxe /x

2 2 ' '

If the drum is geared, the engine will make g revolutions to

156 Determining The Bizb Of Hoisting-Plants.

one of the drum, or the leverage of the engine is increased to g times what it would be if directly connected, and the equation becomes

This is the general equation for all hoisting-engines. If they are directly connected, the ratio of gearing, g, equals 1.

When the weight of the load, size of the drum, and steam pressure are given to determine the size of the cylinders, there are two unknown quantities in the equation, viz. : A and L. Here L can be assumed and the equation solved for A, from which the diameter can be obtained. The usual practice is so to proportion the cylinder that the length of travel is 1 J to 2 J times the diameter of the piston. K the value of L chosen for trial gives a ratio of stroke to diameter outside of these limits, another value must be taken for L, and another solution made. If the ratio is decided upon first, then the area can be expressed in terms of the stroke, and there is only one unknown quantity in

the equation. Thus rd 12L or d (12L being the length

14t4JJ of the stroke in inches), and A tt — — ; which, substi- tuted in equation 5, gives

Having obtained the size of cylinders, and knowing the peed of hoisting and size of drum, the speed of the engine can be obtained, and the speed of the piston can be investi- gated. The speed of hoisting, in feet per min., divided by the circumference in feet, will give the number of revolutions of the drum per minute. If the drum is geared, the engine will make g times as many r. p. m. (revolutions per minute) as the drum,

The piston-apeed in feet per min. 2L x N, or

Lg

:. 2LS Fiston-speed g. (8

Determining The Size Of Hoisting-Plants. 157

Where the engine is direct-acting, g 1 in both equations, T and 8.

The horse-power available for hoisting when the engine is running at full speed will be expressed by the formula :

H. P. of engine x e, (9)

and the horse-power required to raise the load will be :

In the examples here given the weight of the car is taken afr and the weight of the cage as of the weight of the ore hoisted. These together make the dead load, C, equal to the weight of the ore, 0. These are suflSciently close to the usual practice for an illustration of the method of using the formulas.

As an example, take a double-cylinder engine geared to a single drum, to find the size of cylinders required under the following known conditions : Vertical shaft is 400 ft. deep, cage to be hoisted in one minute ; the weights are, cage 900 lbs., car 600 lbs., ore 1500 lbs., rope 400 lbs. ; steam pressure, P, is 60 lbs., e 0.7, g f .01 (assumed), D 4 ft. and L may be taken as 1 J ft. for a trial solution ; then,

W=C + 0-hR (600 + 900) + 1500 + (400 x 1) 3400 lbs.

F Wf 34 lbs. Substituting in equation 5,

(W + F)2 PxAxoXexg, we have

(3400 -h 34) I 60 X A x Y X 0.7 X 4, whence A 54.6, and d 2 JA 8.33 ; say 8J in.

The stroke, L, was taken as 18 inches for a trial solution,, and this gives a well-proportioned cylinder, viz., 8 J in. in dia. X 18 in. stroke.

The speed of the piston can be tested by equation 8 :

which is within the limits for these engines.

158 Pbtermining The Size Of Hoistino-Plants.

From equations 9 and 10 combined, the mean effective-pres- sure required in the cylinders to perform the work can be de- termined. Substituting the known values in these equations, placing one equal to the other, and solving, we have

3434x400 2x66.75 / 400x4

whence, P 45,

which, with 60 lbs. at throttle, corresponds to a cutoff of about J. As both cylinders are in use, the area has been doubled in the above calculation.

With double-drum bolsters, where the descending cage and car counterbalance the ascending ones, the general equation 5 still applies, but the value of W and F are changed. Referring to Fig. 2, when a loaded car is to be started from the bottom of the shaft and an empty car is being lowered at the same time,

W=(R+C + 0) — C R + 0, and F=(R + 2C + 0)f,

which values must be used in the first member of equation .5.

As an example, take a bolster raising a load from a double- compartment shaft 2000 ft. deep in one minute : 0 5000 lbs., C 5000 lbs., R 6000 lbs., D 8 ft., P 60 lbs., engine directly connected (hence g 1), f 0.01, e 0.7. Taking L 4 ft. for a trial and substituting in equation 5 to find the size of cylinders,

(W + F)? PxAx|xexg,

(11000 + 210) I 60 X A X I X 0.7 X 1, A =534, d=2 J:_=26Jin.

This gives a cylinder 26 J in. in diameter by 48 in. stroke. Determining the piston-speed by equation 8,

Determining The Size Of Hoisting-Plants. 159

While the proportions of the cylinders follow the usual practice, the piston-speed exceeds the limits previously set for this class of engines, viz., 400 to 600 ft. per min. This speed can be re- duced by choosing a smaller value for L in equation 5, which will give a cylinder larger in diameter. Thus, if the length had been taken as 44 in., or L 3f ft., d would have been 27

in., and the ratio— 1.6 +, and the piston-speed 584 ft.

per min.

Or, instead of shortening the stroke, the number of revolu- tions can be cut down by increasing the diameter of th0 drum ;

thus, if D 9 ft. and L 4 ft., d will be 27f in., the ratio -g-

1.73, and the piston-speed 566 ft. per min.

Conical drums, as already noted, are intended to equalize the varying load on the engine, due to the change in length and weight of the rope as the cage ascends and descends. As these engines are used where every economy is desirable, they are usually direct-acting and fitted with double drums.

The minimum diameter of the drums is determined by the size of the rope.

Referring to Fig. 3, let D represent the small diameter of the drum in feet ;

y diameter of large end of drum in feet.

C weight of cage and car in pounds.

O weight of ore in pounds.

RZ weight of the long length of rope when cage is at the bottom of the shaft.

Rs weight of the short length of rope when cage is at the top of the shaft.

Then,

D V

(C -f O + RZ) (C + R5) - moment of the resistance

when the load is at the bottom. Fig. 3, position A, and (C+O+R5)

y D

— (C + RZ) moment of the resistance when the load is at the top, Fig. 3, position B. The object of the conical drums

160 Detbrmining Thb Sizb Of Hoistinq-Plants.

being to keep this moment constant, these two values must be equal, and

(C + O+EOD — (C + R)y=(C + 0 + R?)y — (C + IM)D(11)

Solve for y. Then, taking either end case, say when the load is at the bottom, the moment of the resistance of the loads, with friction added, must equal the moment of the power of the engine. This, following the same form as equation 5, gives :

(C + O + RO (1 + f ) 2 - (C + R) (1 - f ) I

PxAx-xexg. (12)

Taking as an example the one used for the engine with double cylindrical drums, depth of shaft 2000 ft. plus 38 J ft. to head sheave above landing, S 2000 ft. per min., 0 5000 lbs., C 5000 lbs., Rl. 6100 lbs., lis. 100 lbs., D 7 ft, P 60 lbs., g 1, f .01, e 0.7, L for trial 4 ft., to find diameter of cylinder.

From equation 11,

(C + O + ROD — (C + R)y (C + 0 + Ity)y— (C + IM)D, (16100 X 7) — (5100 y) (lOlOOy) — (11100 x 7),

whence, y 12.52 ft. diameter of large end of drum. Substituting in equation 12,

C + 0 + 5000 + 5000 +6100 =16100 lbs.,

1 + f 1.01,

C + 5000 + 100 5100 lbs.,

1 — f 0.99, we have

7 12 'i2 4

(16100x1.01 x)— (5100x0.99 x- 2-)=60xAx2X

0.7 X 1, 56914 — 31607 84 A, whence A 301, and

d 2 J4 19f

in.

From equation 8

A 2Ls 2 X 4 X 2000 , .„ .

"2 D being taken here aB the mean diameter.

Determining The Size Of Hoisting-Plants. 161

There must be a division left between the ropes on a conical drum in order to furnish positive grooves for the rope, so that the large coils cannot slip down over the smaller ones ; hence the drum must be longer than those of the cylindrical design, even when the mean diameter of the conical drum is the same as the diameter of a cylindrical one.

In the Koepe system, as applied to a double-compartment shaft, there is a tail-rope of the same weight as the hoisting-rope fas- tened to the bottom of one of the cages, passed around a sheave in a pit at the bottom of the shaft, and attached to the bottom of the other cage. Then, in whatever position the cages are in the shaft, there is the same weight of rope hanging in each compartment. Thus the entire weight of the hoisting mechan- ism is in perfect balance at all times, and the engine only has to raise the weight of the ore and overcome the friction of the moving parts. The main rope may be wound on a pair of cylindrical drums, or it can be wrapped back and forth over a pair of multiple-grooved sheaves, as is done in rope drives for many purposes. It is essential that a positive grip is taken on the rope by the driving mechanism, or else its creeping on the driving-sheaves will make the indicators show a false position for the cages, and make accidents of overwinding a great source of danger.

The calculation of the size of the engines required can be made by equation 6. The engines would usually be direct- acting.

As an example, assume the same conditions as have been used before :

S 2000 ft. per min. 0 5000 lbs. C 6000 lbs. R 6000 lbs. P 60 lbs., e 0.7, f 0.01, g 1, D 8 ft, L 4 ft., for trial.

(W + F) PxAx5;xexg. (5)

W O 5000 lbs. F f (0 + 2C -f- 2R) 0.01 x 27000

(5000 + 270)|= 60 X A x|x 0.7 x 1. A 251.

3r

18 in.

Vol. Xxxiii. — 11

162 Dbtbbmiking Thb Sizb Of Hoistinq-Plants.

This is a rather small diameter for a cylinder of this length, as its length is 2f times the diameter, which exceeds the ratio already recommended. If L were taken as 36 inches, the area would be 835 sq. in., corresponding to 20f in. diameter, which gives a cylinder with better proportions.

The piston-speed can be obtained from equation 8, and the mean eflfective-pressure required, when hoisting at full speed, can be found from equations 9 and 10 combined.

It is interesting to compare the sizes of the three types of engines, hoisting the same load at the same speed. These tabulated are :

Cylindrical Druma, 9.76 69198 29

Conical Drums, 9.76 24669 19|

Koepe System 9.76 26727 19}

The conditions in all of the above were the same as used in former examples, except that the diameters of drums are all taken as 9.76 ft., which is the mean diameter of the conical drums. The engines are direct-acting, the shaft has double compartments, and the cages work in balance ; C 5000 lbs., O 5000 lbs., R 6100 lbs., P 60 lbs., L 4 ft., f .01, e 0.7, g 1, S 2000 ft. The piston-speed is 522 ft. per min. in each case.

The table shows that cylindrical drums are not as economical to operate as either the conical drums or the Koepe system. The conical drums are expensive to make, as the grooves have to be formed spirally and with an increasing radius, and each problem requires a specially-designed drum, so there can be little use made of stock patterns. They are only used where the rope is heavy, and the economy of accurate counter-balanc- ing is clearly indicated, and will offset the extra cost of manu- facture.

The Koepe system is a simple method of counter-balancing, and the principle could often be applied to existing plants with cylindrical drums by adding a tail-rope aud an idle sheave at the bottom of the shaft, provided there is suflSlcient sump-room for the sheave and its slide. The objection to the Koepe sys- tem, where used without drums, is the liability of the ropes to creep on the sheaves, causing the indicators to give a false rec- ord and so increase the danger of overwinding.

Dbtbrmining The Sizb Of Hoisting-Plants. 163

Flat ropes of rectangular cross-section are wound on a reel like a tape. When the load starts from the bottom of the shaft the rope winds on the center of the reel, which is of small diameter, and then, as the load rises, the successive layers increase the diameter of the coil on the reel ; thus the leverage of the load increases and the weight decreases. If the original diameter of the barrel of the reel and the thickness of the rope are properly chosen, the moment of the resistance will be constant.

The proportions of the reel can be found as follows :

Let D diameter of the barrel in feet.

y diameter of coil of rope, when cage is at the top, in ft

C weight of cage and car, O weight of ore, and R weight of rope, all in pounds, as before.

1 length of rope or depth of shaft in feet.

t thickness of rope in inches.

n number of layers of rope in coil.

y+D (y D) 12

Then, referring to Fig. 4, w x n 1, and — n.

Substituting the latter value of n in the first equation gives

y±P,v(yizP)l?_i

(y*-D') l. (13)

From equation 18, knowing t, the value of y can be obtained,

or having decided on y, the equation can be solved for t. The

minimum diameter of the barrel, D, depends on the thickness

of the rope, and can be calculated from Mr. Hewitt's equation,

Ea previously given : k in which bending-stress in

2.06 + C, d

pounds, E modulus of elasticity 28,500,000, a aggre- gate area of the wire in sq. in., K radius of the bend in inches, d diameter of individual wires, and C a constant depending on the number of wires in a strand. With flat rope, d J the thickness of the rope, and C 27.54.

The moment of the resistance at starting the load would be the moment of the weight, C + 0 + R plus the friction, acting

with the lever arm as in equation 5.

164 Situation As To Specifications For Steel Rails.

The ideal case would be one in which the work of hoisting was constant at every part of the hoist ; but the thickness of the rope may be such that the leverage of the load increases faster or slower than the weight of the load decreases, thus making the work on the engine to vary during the trip. In such a case, the design must be tested with the cage at various points, to make sure that the engine has sufficient power to handle the loads at the desired speed at all points. For this, equations 9 and 10 may be used.

Generally these hoists are arranged in pairs, so that one cage ascends while the other descends. Then the necessary large diameter of the reel, to make the work constant on the engine, can be found by equation 11, used for conical drums, and the size of the engine from equation 12. After this the thick- ness of the rope can be found by equation 13.

K the reels cannot be made of such diameter as to make the work of hoisting uniform throughout the trip, with a reasonable thickness of rope, then the case must be considered by itself, and the design must be tested with the cage in positions suf- ficiently numerous to prove that the engine that will start the load is strong enough to handle it at all points.

The Present Situation as to Specifications for Steel Rails.

By William R. Webster, Philadelphia, Pa.

(New York and Philadelphia Meeting, February and May, 1902.)

At the Richmond meeting in February, 1901, 1 presented for discussion the jproposed rail-specifications of Committee No. 1 of the American Section of the International Association for Testing Materials, with a review of their work, and other mat- ters relating to the heat-treatment and chemical composition of steel ( Trans. xxxi., 455). In order to bring out the views of our members on the important points referred to, I oflered for discus- sion the following questions and comments (TVans., xxxi., 972) :

1. The advantages to be gained by using more metal in the flanges and web of the heavier sections of rails.

Situation As To Specifications For Steel Bails. 165

" 2. The advantages and diaadvantages of using a higher-carbon steel than that called for in the specifications under consideration in this discussion.

''3. The amount of shrinkage in a 80- ft rail, to be specified as an accurate check on the finishing-temperature in rolling.

'' 4. The advisability of requiring a drop-test on each blow of steel.

"I appreciate that it is not onlv the finishing-temperature which must be con- sidered, but that sufiicient work roust be put on the steel at a temperature low enough to break up the coarse structure and produce the tough steel desired. This is recognized by some who are rolling rails direct from the ingot ; and they claim that better results are produced by this method than by re-heating the bloom. This might be considered another point for discussion.''

We had, on the points thus raised, a very good discussion, bringing out clearly their value and mutual bearing, and un- doubtedly exerting an important influence on the general study of the subject. All these points have been taken up since that meeting by other technical societies and by railroad companies, and have been either recognized in commercial specifications, or made subjects of further investigation.

In March, 1901, the Rail-Committee of the American Rail- way Engineering and Maintenance of Way Association sub- mitted, as a matter of information, to the annual convention of that Association at Chicago, these rail-specifications, with my Richmond paper. The Committee reported in favor of using 33-ft., instead of 30-ft., rails, since cars were now built long enough to carry them, and 10 per cent, of the joints would be saved by their use. As to the proposed change of section, the Report said :

"We feel hesitancy in suggesting new sections ; hut if all rails hereafter are to be rolled at a lower temperature, we think the section should be modified, and that the sooner the change is made the better for all concerned. This matter has been developed so recently that we are not prepared to submit new sections. How- ever, the A. S. C R sections are not the only ones that will have to be modified on account of this change in finishing-temperature ; but other sections will have to be modified in the same way — that is, by providing additional metal in the flange."

In the discussion the point was made that it might be a mis- take, in rolling with steel of the present carbon-tenor, to rely altogether on the lower finishing-temperature for securing a better quality of rail, thus sacrificing the advantages of the higher carbon, which could be used with safety in rails finished at a lower temperature, so as to realize the advantages of both high carbon and low heat.

166 Situation As To Specifications For 8Tekl Bails.

This led to my coramunication of March 25, 1901, to the American Society of Civil Engineers, requesting the appoint- ment of a committee to investigate and report on standard rail-sections, and giving the reasons why the matter should be taken up.

The Board of Direction of that Society made the following report at the annual convention of June 25, 1901 :

**AiiotJin5NT8 IN Favor.

1. The American Society of Civil Engineers has already recognized this sub- ject as a proper one for consideration and report by a Special Committee.

2. The Special Committee, thus authorized, became convinced that experience in the use of steel rails had reached a stage at which standard patterns were not only feasible but desirable, and accordingly, in August, 1893, recommended a series of rail-sections for given weights per yard.

3. The result of the report of the Special Committee may be indicated by these two facts : 1. That in February, 1881, the rail-mills in this country had 188 different patterns which were considered standard, and that 119 patterns of 27 different weights per yard were regularly manufactured. 2. That in 1899, or six years after the publication of the report of the Special Committee, fully 75 per cent, of all the rails rolled in the United States were of the pattern recom- mended in that report.

4. It would seem, therefore, that a suggestion that these sections are in any respect unsatisfactory should not be disregarded ; for if the sections now recog- nized as standard are to be modified in any respect, such modification should have an endorsement of significance equal to that given to the original sections.

'5. To investigate and report upon engineering matters which are of general interest to the profession is a distinctly proper function of this Society. It is submitted that a report from a Special Committee on Rail-Sections should sum- marize the present state of the art of raU-making, and cover an investigation of all questions relating thereto, whether of section, composition of the material, or processes of manufacture ; and that such a report, whether it recommended a change in any of the sections heretofore established or not, would be of great value.

"Arguments Aoainst.

''1. The rail-sections recommended by the Special Committee of the Society in 1893 have been very generally adopted, and are now recognized as standard.

''2. Well-established standards should not be questioned without good reasons, and no Special Committee should be appointed to reconsider the present standard sections unless upon evidence that a change of section is necessary or advisable.

*'3. No such evidence has been placed before the Society or the Board of Direction.

"4. In any case, it does not appear that a Special Committee, if appointed, should be limited by its instructions to the consideration of proposed changes in section alone, as questions of composition and manufacture may be quite as influential in any failure of the present standard sections' to meet requirements which may be demonstrated.

Situation As To Specifications For Stbbl Rails. 167

'' Recommendation.

" After careful oonaideration, the Board of Direction, believing that the resuions in fayor of the appointment of the proposed Committee outweigh those against sach appointment, makes the following recommendation :

"That a Special Committee be appointed, as provided in the Constitution of the Societj, for the foUowing purposes :

"1. To report upon the results obtained in the use of rails of the sections pre- sented to the Society in Annual Convention, August 2, 1893, by a Special Committee appointed for that purpose.

To report whether any modification of any of said sections is advisable, and, if so, to recommend such modification.

"3. To report upon the recognized practice as to chemical composition and mechanical treatment used in the manufacture of rails, and the manner of inspec- tion of the same.

" 4. To report upon the advisability of the establishment of a form of specifi- cation covering the manufacture and inspection of rails.

" 5. If found advisable, to recommend a form of specification for the manufac- ture and inspection of rails."

This report was discussed ; and the result of the subsequent postal ballot was greatly in favor of the appointment of the Committee. This appointment has recently been made ; and the Committee has been instructed to report on the five points rec- ommended by the Board of Direction.

There is no intention to change the section of the rails, if the mills, by changing their methods of rolling, can produce better structural results in heavier rails. On the other hand, if this cannot be done, and if, by a change of section, the manufac- turers can produce a much better rail, the engineers are willing to meet them half-way, and decide the matter on its merits.

At their annual meeting in Niagara Falls, in June last, the American Section of the International Association for Testing Materials adopted their rail-specifications.

On October 1, 1901, the Pennsylvania Railroad Company embodied in its new rail-specifications the minimum shrinkage clause for a 30-ft. rail, as follows :

" The number of passes and speed of train shall be so regulated that on leav- ing the rolls at the final pass the temperature of the rail will not exceed that which requires a shrinkage-allowance at the hot-saws of more than in. for 85- Ib. and in. for 100-lh. rails ; and no artificial means of cooling the rails shall be used between the finishing-pass and hot-saws."

They also made a new departure in the chemical composition of their steel, decreasing the carbon and manganese when the

168 Situation As To Specifications For Stkbl Rails.

phosphorus is over 0.07 per cent., in order to give steel of equivalent hardness and avoid getting steel too hard and brittle. The clause is as follows :

''The steel of which the rails are rolled shall contain not less than 0.40 nor more than 0.55 of 1 per cent of carbon, where the phosphorus exceeds 0.07 of 1 per cent Where the phosphoros is 0.07 of 1 per cent or less, the carbon shall not be less than 0.45 nor more than 0.60 of 1 per cent The manganese in no case shall exceed 1.20 per cent; and where the phosphorus exceeds 0.07 of 1 per cent., the manganese shall not be higher than 1 per cent. Also, in no case shall the phosphorus exceed O.IO of 1 per cent"

In addition to the above, the company now advocates higher carbons, since its drop-tests show that rails finished at a lower temperature give a greater deflection than formerly, when fin- ished at the higher temperature. They also find that higher carbons can be used with safety when the proper check is kept on the lower finishing-temperature. They specify a deflection of not more than 3f in. for 100-lb. rails after the first blow.

In March, 1902, the Rail-Committee of the American Rail- way Engineering and Maintenance of Way Association re- ported to the annual convention several modifications in rail- specifications, the most important of which were a drop-test from each heat of steel, instead of one from each fifth heat, and the introduction of a minimum-shrinkage clause. They did not specify the amount of shrinkage, as they desire to in- vestigate this matter further.

The height of drop specified for the heavier weights of rails was thought by some of the members to be too small in com- parison with the height for the lighter rails. This point will be investigated and reported on.

The specifications, with the modifications referred to (and some other minor ones), were adopted by the Association as its Standard Rail-Specifications.

In the same report, the Committee said :

" The rail-mills have furnished the percentage of their total output of rails rolled to A. S. G. E. Section during 1901, as follows :

Per cent.

National Steel Co., . . . 95.0

Pennsylvania Steel Co., 93.2

Illinois Steel Co., 70.0

Cambria Steel Co., 73.5

Carnegie Steel Co., 72.0

Maryland Stel Co., 52.1

Ickawanna Steel Co., 37.2

Situation As To Specifications For Stbkl Rails. 169

" The low percentage of A. S. Q E. output from the Maryland Steel Co. is ex- plained hy the fact that a large amount of rail of special pattern was rolled for export ; also that the Pennsylvania lines east of Pittshurg, and the Baltimore & Ohio Bailroad Co., used special patterns.

' ' The Lackawanna Steel Company rolled a large tonnage of the Dudley pattern for the New York Central lines.*'

The next step will be for Committee No. 1 of the American Section of the International Association for Testing Materials to take up for consideration the modifications of its specifica- tions made at Chicago, and report them at the annual meeting in Atlantic City, K J., on June 12, 18 and 14, 1902. A cor- dial invitation will be extended to the members of all Commit- tees and Associations who have discussed these rail-specifica- tions to attend and take part in the discussion. There is little doubt that the modified specifications will be approved by the American Section.

I have stated the present situation in detail, because the subject is one of the most important now before us, and con- tributions from all quarters will be pertinent, useful and wel- come. The work thus far done will naturally form a basis for the new Rail-Committee of the American Society of Civil Engi- neers, which has been directed to report a form of rail-specifica- tion covering both the manufacture and the inspection of rails. That body will, no doubt, improve on the present specification, and bring matters up to date in every particular. When this has been done, the other societies will, no doubt, accept the result ; and it is not too much to expect that we shall soon have in use American standard rail-specifications reflecting credit upon all who have assisted in this important work.

The International Railway Congress meets at Washington, D. C, in 1905 ; and the presentation on that occasion of such specifications, expressing a general agreement in American theory and practice, would, without doubt, greatly influence the action of the Congress in this department.

170 Specifications For Steel F0Rgino8 And Steel Castings.

Specifications for Steel Forgings and Steel Castings.

BY WILLIAM R. WEBSTER, PHILADELPHIA, PA. (New York and Philadelphia Meeting, Febraary and May, 1902.)

In view of the good results which have followed the wide discussion of the rail-specifications of the American Section of the International Association for Testing Materials, I now offer for discussion its specifications for steel forgings and steel castings. It is not necessary to emphasize the importance of reaching definite conclusions on these subjects. Engineers, consumers and manufacturers are alike interested in securing good, reliable, uniform steel.

In this connection, I would call particular attention to the important paper read by Mr. C. H. Ridsdale, last September, before the Iron and Steel Institute, as bearing on them ; and, for convenience of reference in the discussion, I append the Table in Section VI. of his paper, on " Manifestations, Classified un- der Heads of Faults of Different Types, appearing after Treat- ment by the User, for Tracing their Probable Source."*

The discussion of these specifications will be practically a con- tinuation of our former discussions on " The Physics of Steel."

We have passed through a period in which the chemical composition of steel has received the greatest prominence ; but failures of steel forgings and castings of the best chemical com- position have shown that we could not control the quality of the finished product by the chemical composition alone. It must be admitted that differences in the physical properties of the steel, greater than those due to small variations in composi- tion, are produced by heat-treatment, both in connection with the mechanical work of forging and otherwise. The present result is a strong tendency to deem the heat-treatment more impor- tant than the chemical composition. I think the mean course is the safer. We should give them equal importance ; for we know that to produce the best results we must start with a good

Jour. L and S. Inst., No 2, pp. 94, 95.

Spbcipications For Stebl Foroinqs And Stbbl Castings. 171

uniform material, and employ also, under intelligent supervision th6 best methods of manufacture and subsequent working.

The annealing of forgings and castings is much neglected The manufacturers who are doing the highest class of work for our Government and other customers, under rigid specifications, assert that all such work should be annealed. Other manufac- turers of a cheaper class of work claim that annealing is not necessary, and, in some cases, even go so far as to say it is in- jurious. They adduce results to prove their assertions. But it is only necessary to repeat the annealing under proper con- ditions, to prove that the source of such alleged injury was in the method of annealing used. In many cases, attempts are made to anneal forgings that have been finished at too high a temperature, without first allowing them to cool down below the critical point. This is merely slow cooling, and makes the material much worse than it would be if allowed to cool in the air.

In consideration of such controversies, I would suggest that discussion be directed towards the heat-treatment of steel, with an endeavor to decide some of the disputed points, and thus to improve the methods of manufacture.

Appendix.

Standard Specifications for Steel Forgings.

Process of Manufadwe.

1. Steel for forgings maybe made by the open-hearth, crucible or Bessemer process.

Chemical Properties.

2. There will be four classes of steel foldings which shall conform to the following limits in chemical composition :

orgi"g> of

rbon steel.

-tempered

annealed.

orgings of ckel steel, -tempered annealed.

s

So

s o o

Per cent.

Per cent.

Per cent.

Per cent.

Phosphorus shall not exceed... 0.10

Sulphur " ... 0.10

Nickel

3.00-4.00

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8Pbcifigati0N8 For Stsel Forqings And Steel Castings. 175

Physical Properties.

3. The ininimnin physical properties required of the different-sized forgings of each class shall be as follows :

J5

Pounds per square inch.

58,000 29,000

Per cent.

Soft Steel or Lmo-Oarhon Steel.

For solid or hollow forgings, no diameter or thickness of section to exceed 10 in.

75,000

37,500

80,000

Elastic limit.

75,000 70,000

37,600 35,000

Oarhon-eel Not Annealed,

For solid or hollow forgings, no diameter or thickness of section to exceed 10 in.

Carhon-SUel Annealed.

For solid or hollow forgings, no diameter or thickness of section to exceed 10 in.

For solid forgings, no diameter to exceed 20 in. or thickness of section 15 in.

For solid forgings, over 20 in. in diameter.

90,000 55,000

Tensile strength.

Elastic limit.

Elongation

In 2 in.

Contraction of

area.

Pounds per square inch.

Per cent.

85,000 50,000

80,000 45,000

Carbon-Stedf Oil-Tempered.

For solid or hollow forgings, no diameter or thickness of section to exceed 3 in.

OarbonSteel, Oil-Tempered.

For solid forgings of rectangular sections not exceeding 6 in. in thickness, or hollow forgings the walls of which do not exceed 6 in. in thick- ness.

For solid forgings of rectangular sections not ex- ceeding 10 in. in thickness, or hollow forgings the walls of which do not exceed 10 in. in thickness.

80,000

60,000

80,000

46,000

80,000

45,000

Nickel-SUel Annealed.

For solid or hollow forgings, no diameter or thickness of section to exceed 10 in.

For solid forgings, no diameter to exceed 20 in. or thickness of section 15 in.

For solid forgings, over 20 in. in diameter.

176 Specifications For Stbbl Forgings And Stbbl Castings.

Nickd'Sudf Oil-Tempered, For solid or hollow forgings, no diameter or 95,000 65,000 21 50 thickness of section to exceed 3 in.

For solid forgings of rectangular sections not exceeding 6 in. in thickness, or hollow forgings the walls of which do not exceed- 6 in. in thick- 90,000 60,000 22 50 ness.

For solid forgings of rectangular sections not exceeding 10 in. in thickness, or hollow forgings the walls of which do not exceed 10 in. in thick- 85,000 55,000 24 45 ness.

4. A specimen 1 hj 0.5 in. shall hend cold 180° without fracture on outside of bent portion, as follows :

Around a diameter of 0.5 in., for forgings of soft steel.

Around a diameter of 1.5 in., for forgings of carbon-steel not annealed.

Around a diameter of 1.5 in., for forgings of carbon-steel annealed, if 20 in. in diameter or over.

Around a diameter of 1 in. , for forgings of carbon-steel annealed, if under 20 in. in diameter.

Around a diameter of 1 in., for forgings of carbon-steel oil-tempered.

Around a diameter of 0.5 in., for forgings of nickel-steel annealed.

Around a diameter of 1 in., for forgings of nickel-steel, oil-tempered.

Tei-Pieee9 and Methods of Testing,

5. The standard turned test-specimen, one-half inch (0.5) diameter and 2 in. gauged length, shall be used to determine the physical properties specified in paragraph No. 3.*

6. The number and location of test-specimens to be taken from a melt, blow, or a forging shall depend upon its character and importance, and must, therefore, be regulated by individual cases. The test-specimens shall be cut cold from the forging or full-sized prolongation of same parallel to the axis of the forging and half-way between the center and outside, the specimens to be longitudinal— i.e., the length of the specimen to correspond with the direction in which the metal is most drawn out or worked. When forgings have large ends or collars, the test- specimens shall be taken from a prolongation of the same diameter or section as that of the forging back of the large end or collar. In the case of hollow shaft- ing, either forged or bored, the specimen shall be taken within the finished sec- tion prolonged, half-way between the inner and outer surface of the wall of the forging.

7. The specimen for bending-test, 1 by 0.5 in., shall be cut as specified in paragraph No. 6. The bending-test may be made by pressure or by blows.

8. The yield-point specified in paragraph No. 3 shall be determined by the careful observation of the drop of the beam, or halt in the gauge of the testing- machine.

9. The elastic-limit specified in paragraph No. 3 shall be determined by means

The specifications contain a diagram of the proposed section, omitted here. R W. R.

Specifications For Steel Foroings And Steel Castings. 177

of an extensometer, which is to be attached to the test-specimen in manner as to show the change in rate of extension nnder uniform rate of loading, and will be taken at that point where the proportionality changes.

10. Tamings from the tensile-specimen or drillings from the bending-specimen or drillings from the small test-ingot, if preferred by the inspector, shall be used to determine whether or not the steel is within the limits in chemical composition specified in paragraph No. 2.

Finish.

11. Forgings shall be free from cracks, flaws, seams or other injurious imper- fections, and shall conform to dimensions shown on drawings furnished by the purchaser, and be made and finished in a workmanlike manner.

Initpeetion.

12. The inspector representing the purchaser shall have all reasonable facili- ties afiPorded to him by the manufacturer to satisfy him that the finished material is furnished in accordance with these specifications. All tests and inspections shall be made at the place of manufacture, prior to shipment

Standabd Specific ations fob Steel Castinos.

Process of Manufacture,

1. Steel for castings may be made by the open-hearth, crucible or Bessemer process. Castings to be annealed or unannealed as specified.

Chemical Properties.

2. Ordinary castings, those in which no physical requirements are specified, shall not contain over 0.40 per cent, of carbon, nor over 0.08 per cent, of phos- phorus.

3. Castings which are subjected to physical test shall not contain over 0.05 per cent, of phosphorus, nor over 0.05 per cent of sulphur.

PhycaL Properties,

4. Tested castings shall be of three classes : '' hard,'' medium," and soft." The minimum physical qualities required in each class shall be as follows :

Tensile strength, lbs. per sq. in., Yield-point, lbs. per sq. in.. Elongation, per cent in 2 in., . Contraction of area, per cent, .

5. A test to destruction may be substituted for the tensile test, in the case of small or unimportant castings, by selecting three castings from a lot This test shall show the material to be ductile and free from injurious defects, and suitable for the purposes intended. A lot shall consist of all castings from the same melt or blow, annealed in the same furnace charge. ▼OLu zxziii. — 12

Hard

Medium

Soft

castings.

castings.

castings.

85,000

70,000

60,000

38,250

31,500

27,000

178 Specifications For Steel Forgings And Steel Castings.

6. Large castings are to be suspended and hammered all over. No cracks, flaws, defects nor weakness shall appear after such treatment.

7. A specimen 1 in. x 0.5 in. shall bend cold around a diameter of 1 in. without fracture on outside of bent portion, through an angle of 120° for ''soft'' castings, and of for '' medium '' castings.

Test-Pieces and Methods of Testing,

8. The standard turned test-specimen, 0.5 in. diameter and 2 in. gauged length, shall be used to determine the physical properties specified in paragraph No. 4.*

9. The number of standard test-specimens shall depend upon the character and importance of the castings. A test-piece shall be cut cold from a coupon to be molded and cast on some portion of one or more castings from each melt or blow or from the sink-heads (in case heads of sufficient size are used). The coupon or sink-head must receive the same treatment as the casting or castings, before the specimen is cut out, and before the coupon or sink-head is removed from the casting.

10. One specimen for bending-test 1 in. x 0.5 in. shall be cut cold from the coupon or sink-head of the casting or castings as specified in paragraph No. 9. The bending-test may be made by pressure, or by blows.

11. The yield -point specified in paragraph No. 4 shall be determined by the careful observation of the drop of the beam or halt in the gauge of the testing- machine.

12. Turnings from the tensile specimen, drillings from the bending-specimen, or drillings from small test-ingot, if preferred by the inspector, shall be used to determine whether or not the steel is within the limits in phosphorus and sulphur specified in paragraphs Nos. 2 and 3.

Finish.

13. Castings shall be true to pattern, free from blemishes, flaws or shrinkage- cracks. Bearing surfaces shall be solid, and no porosity shall be allowed in posi- tions where the resistance and value of the casting for the purpose intended will bo seriously afiFected thereby.

Inspection.

14. The inspector representing the purchaser shall have all reasonable facili- ties afforded to him by the manufacturer to satisfy him that the finished material is furnished in accordance with these specifications. All tests and specifications shall be made at the place of manufacture, prior to shipment.

The specifications contain a diagram of the proposed section identical with that in the article on "Steel Forgings," and here omitted.— B. W. R.

The Mbtallurgt Op Titanium. 179

The Metallurgy of Titanium.

Br AUGU8TE J. ROSSI, NEW YORK CITT. (New York and PfiUadelphia Meeting, February and May. 1902.)

Wb cannot expect, within the limits of this paper, to treat this subject exhaustively, but will endeavor, in the following, to present it in as concise a manner as is consistent with a clear exposition of its importance.

Ores of titanium, titaniferous iron-ores (that is, iron-ores con- taining a notable amount of titanic acid, TiOj, say not less than 5 per cent, generally 10 to 20 per cent., and frequently more, up to 40 per cent, or thereabout), occur all over the world in immense quantity, " in mountain masses," constituting in some localities, as in Sweden, Norway, Canada, the Adiron- (lacks (N. T.), in North Carolina and other States of the Union, the geological formation itself, the igneous rocks having, in many places, been so permeated with the metallic oxides as to justify their being called iron-ores.

As a rule they are Bessemer ores, quite free from phos- phorus and sulphur, though not invariably so. When the per- centage of titanic acid is very high, that of the iron is low, but the proportions do not necessarily vary in the same ratio ; that is, a rich ore may contain more titanic acid than one lower in iron. The percentage of iron varies, being as low as 85 to 36 per cent in real ilmenite. It is more generally not less than 50 to 55 per cent, reaching often an average of 58 to 60 per cent, and as high as 63 to 65 per cent

It is obvious that if these ores were to be considered in the same light as other iron-ores, equally rich in iron, they would form an excellent stock for blast-furnaces for years to come, as their supply might be called inexhaustible, and they could

Becsjitart's Note.— This paper was prepared for the Franklin Institute, and presented at a joint session of the Mining and Metallurgical Section of that Society with this Institute, held May 15, 1902, at the Manufacturers' Cluh, Philadelphia.

180 The Metallurgy Of Titanium.

take the place, in part or wholly, of other iron-ores free from titanium, of which the exhaustion, in a comparatively short time, in certain districts can be foreseen, owing to the tremen- dous demands made on them by our modern monster blast- furnaces. In this sense we are justified in saying that the met- allurgy of titanium is one of pre-eminent importance, as it implies the use of these ores, which may justly be called the resources and reserves of the future, whn they will be appre- ciated at their full value, and the prejudices against them will be removed, as gradually they are getting to be. " The verdict against them," as has been said by others than ourselves in the discussion of some of our papers on the subject, read before the American Institute of Mining Engineers, " is unjust, based on entirely insufficient grounds, and far from creditable to the progressive spirit of American metallurgy."

Generally low in silica, free from impurities, such as phos- phorus and sulphur, they are particularly well adapted in the blast-furnace for the production of a stock well suited for the open-hearth process (either acid or basic), which is gradually supplanting, at least competing more seriously with, its rival, " the pneumatic or converter process."

Some of the objections raised against the use of these ores in the blast-furnace are so unreliable, so contradictory, so much in opposition to actual facts, that it is really puzzling to find out on what ground they were originally founded.

Opinions in this respect seem to have been taken already made, without any personal control or even desire to ascertain the authenticity, reality or importance of certain statements, and handed down from one to another.

We have not been able to find one metallurgist who could tell us he had used these ores, or that, using them, he had ex- perienced any trouble thereby. They have brought forward the stereotyped objections and rested there : " Sit pro ratione voluntas .'"

These objections have appeared in many scientific publica- tions (easily quoted), and often simultaneously with their refu- tation by actual experiments on the subject. For instance, to mention one of them, it has been stated that the presence, in a blast-furnace slag, of 1 per cent, of titanic acid, or thereabout, was sufficient to render it so inftisible as to transcend the heat

The Metallurgy Of Titanium. 181

capacity of the blast-furnace, the slag being so pasty as to render its tapping impossible, or practically so ; and still, slags con- taining 25 to 35 per cent, of titanic acid have been run for over twenty years from blast-furnaces put up in the Adiron- dack wilderness some fifty years ago, and thousands of tons of such slags, which we have seen and analyzed, form, at the present day, an embankment around the cast-house of the old furnace, of 15 tons daily capacity, still standing as a testimony that this statement as to infusibility of titanic slags cannot in any manner be sustained.

For seven years blast-furnaces have been run in England, at Xorton-on-Tees, with ores containing 40 per cent, of titanic acid and 35 to 36 per cent, of iron, making 200 tons of pig- iron per week. Analyses of the slags have been published by the chemist in charge, as well as all the dta as to composition of ores, charges in coke, ore and fluxes. The slag contained, on an average, 36 per cent, of titanic acid.

We ourselves have run for several months a small blast- furnace of 3 to 4 tons capacity, put up at Bufl:alo, to demon- strate the economy of the smelting of this class of ores when properly dealt with. We have tapped hundreds of tons of slags containing 32 per cent, of titanic acid, which ran 50 feet from the furnace perfectly liquid. In crucible tests that we have made in a furnace with " natural draft," compounds containing 63 to 64 per cent, of titanic acid were obtained, which we have been able to cast in molds.

We give below an analysis of the slags mentioned above as an illustration :

Silica, .

15.90 to 17.50

Titanic acid, .

. 36.18

lame,

Alamina,

Magnesia,

Oxide of iron, .

I. Slag ran at Norton-on*Tees from Norwegian ilmenite containing 40 per cent of titanic acid, 35 to 36 per cent. iron. Analysis by chemist in charge. Wm. iL Bonnron.*

IL Slag ran in Adirondacks in 1856. Average specimen from several hundred poonds of slags picked up from the cinder-bank in 1893 by A. J. Bossi. Analy- br Ledoax & Co.

♦ Trans, y xi., 159.

182 The Metallurgy Op Titanium.

III. Slag run in the small BaiTalo furnace, put up in 1896, at the New York Car- Wheel Works, by A. J. Bossi. Analysis by the chemist of the works.

IV. Compound made in crucible in a furnace with natural draft and poured out in molds. The ores used contained 15 per cent, of TiO,, and on an average 58 per cent, of iron.

Other objections, such as " titanium deposits in the boshes, according to some, in the hearth, according to others, have been advanced against the use of these ores ; and to accept the " sworn testimony " of some blast-furnace managers in a suit in which we were called as expert, " of 1 per cent.," " J of 1 per cent," mere " traces " of titanic acid in an iron-ore, are as sure to produce these deposits as larger percentages. I had been for twelve years technically in charge of the blast-furnaces of Fuller, Lord & Co. (called the Boonton Iron Works), and left in 1876. Our ores contained normally from f of 1 per cent, to 1.25 per cent, titanic acid, and never did we observe such de- posits in our two furnaces. We did not even at that time attach importance enough to the presence of titanic acid in the ores to determine it in our analyses otherwise than as a curiosity.

As regards larger percentages of titanic acid, the successful and continuous running of the Adirondack furnaces for twenty years, that of the English furnace at N'orton-on-Tees for seven years (as attested by a mention of this furnace in a paper read before the British Iron and Steel Institute at their annual meet- ing in 1894), and that of our own small blast-furnace at Buffalo for some months, ought to dispose of these objections, or at least limit them to special cases, as when, by accident, the ob- jectionable phenomena might have been observed in an ab- normal and deranged working of a furnace, smelting, possi- bly unknowingly, a mixture of ores in which titanic acid was present; and it might well be asked whether such derangement was not post hoc rather than propter hoc.

It is well known that obstructions of a similar character, and composed almost entirely oi lime, have been observed in the smelting of ores free from titanium. One of these infu- sible blocks in a blast-furnace was stated to weigh 30 tons. The cause of their formation has been attributed to the excess of limestone charged as flux and of lime in the cinder, very basic silicate of lime being quite infusible per se. In such con- ditions titanium deposits may have contributed to the obstruc- tion without being the cause of it.

The Metallurgy Of Titanium. 183

Some twenty-five or thirty years ago the chemist was a luxury in a blast-furnace plant. A good practical rule of thumb was followed with sufficiently constant success with ores varying but little year after year ; but when the demands of industry justified an increase in the number and size of furnaces, and consequently necessitated a more abundant supply of ores, new ores had to be mixed with those generally used ; and the pres- ence of titanic acid being likely ignored, as well as the manner of dealing with it properly, fluxes may have been indiscrimi- nately added, causing trouble, and the titanic acid was conve- niently made the scapegoat. When we say fluxes, we mean ealcite, as, for many years, limestone (calcite) was considered the only admissible or safe flux in a blast-furnace. Indeed, Percy himself, in his admirable and classic book on metal- lurgy, states that, " as magnesia increases the infusibility of a slag, dolomite as a flux, instead of limestone, should obviously be avoided."

This is another prejudice which has lasted for years, and has been exploded only within the last twenty years, or thereabout. As every metallurgist knows now, dolomite is preferable to cal- cite as a flux, as it increases the fluidity and fusibility of the slag, at the same time removing sulphur fully as efficaciously if not actually better than lime.

Titanate of lime is more infusible still than silicate of lime, and the addition of lime in excess, on general principles, may possibly, with ores very low in silica and containing a large amount of titanic acid in the mixture, have caused the slag to prove less fusible ; but we should not forget, however, that a silico-titanate of lime, containing about equal percentages of silica, titanic acid and lime, — " sphene," as it is called, — is as fusible in a blast-furnace as any good foundry-iron slag, and considerably more fusible than silicate of lime; so that the presence of titanic acid should have increased the fusibility, if a sufficient amount of silica was present, instead of diminish- ing it. We may refer to Analysis ITo. I. of the slags run at Norton-on-Tees as an example.

As to "titanium deposits," strictly so called, that is, for- mations of nitrides and cyano-nitrides of titanium of a cop- per-red color, or of a metallic titanium, as it was claimed by some, they may have been possible in a serious derangement

184 The Metallurgy Of Titanium.

of the working of a blast-furnace occurring under circum- stances independent of its presence, and due to causes entirely foreign to it ; the titanic acid being then an " accessory after the deed," and conveniently assumed to be the principal cause of the mischief.

We have seen in Pittsburg a very fine large specimen of such titanium deposit ; it was copper-red and kept religiously under a glass case. But the well-known metallurgist who had it was conscience-stricken, and owned frankly to us that he had had the curiosity to have it analyzed, and that it was found to con- tain 98J per cent, of copper. As is well known, for many years, and until the researches of Wohler, it was believed that titanium was a red metal, like copper.

In short, titanic acid, properly dealt with in the blast-furnace, will not necessarily prove the cause of trouble. Slags contain- ing some 35 per cent, of titanic acid will run as fluid as silica slags; and.if in an iron-ore the titanic acid be treated as so much silica, and be depended upon and calculated to form one of the principal elements of the slag, with such amount of silica as will be necessarily and tiuavoidably contributed to the slag by the limestone, the ores and the ashes of the fuel, and if a dolomitic stone be used as flux instead of a calcite, titano-silicates of lime, alumina and magnesia will be found to form a very fluid fusible and good slag, and no titanium will remain in the furnace to cause any trouble in a normal or ordinary running.

It is this addition of dolomite as a flux, instead of calcite, that we have successfully experimented with in our small furnace at Buflfalo. (See analysis of slag III.) Both in the Adirondacks (analysis 11.) and in England (analysis I.) at Norton-on-Tees, the composition of the slag was difterent, in this sense, that titanic acid was present to nearly an equal per- centage with lime and silica, reproducing practically the com- position of the mineral sphene perfectly fusible in the blast- furnace— a silieo-titarmte of lime.

In England it was obtained by the addition to the ore, of which the composition is given below, of siliceous flux, in the shape of old bricks, besides the calcite addition, considered indispensable at the time.

The Metallurgy Op Titanium. 185

Ore Used at Nor ton-on- Tees — Norway Ilmenite,

Titanic acid, (average of cargo) 39.20

Silica, 5.70

Ferric oxide, 18.59

Ferroua oxide, 80.00

Manganese oxide, 0.60

Alamina, 2.89

Magnesia, 2.80

Iron, 36.34 per cent.

In the Adirondacks, siliceous fluxes were also added, but they were furnished by the Labrador feldspar, costing nothing, and saving a corresponding amount of limestone. The ore, on on average, contained :

Silica 2.50

Titanic acid, 13.50

Alumina, 1.50

Magnesia, 0.90

Oxide of manganese, 0.13

Phosphorus, 0.020

Sulphur, 0.052

Oxide of iron, 81.90

Metallic iron, 58.43 per cent.

We have published on these questions several papers,t to which we refer the reader for more complete information. In one of them will be found all the data of the run of the small experimental furnace erected at Buffalo.

We should remark, here, that all that we have said above ap- plies to ores really titaniferous, containing, say, not less than 5 per cent, titanic acid, smelted alone. As to ores containing 1 per cent of titanic acid or thereabout, our practice of twelve years in Boonton, N. J., and that of other furnace-men who bought from us ores like those we used (or similar ones of Morris county, in which the average of titanic acid is from 0.55 to 1 per cent., such as those of the Hibernia mine, Mount Pleasant), and are using yet, cannot leave any doubt that per cent, to 1 per cent, of titanic acid in the ore mixture can be com-

Analysis by \Vm. M. Bowron, chemist in charge. See Bo wrongs paper quoted above, 2Vo7w., xi., 160.

t ''Titaniferous Ores in the Blast-Furnace," Trans., vol. xxi., p. 832. ''Smelting of Titoniferous Ores," Ir&n Age, Feb. 6 and 20, 1896.

186 Thb Mbtallurgt Of Titanium.

pletely ignored, so far as affecting in any manner the run of the furnaces or the charges.

But, even assuming an inferior limit of 0.50 per cent, of titanic acid admissible in a mixture, it is difficult to conceive why ores from North Carolina and elsewhere, containing 64 per cent, of iron and 5 per cent, of titanic acid, cannot be used to the extent of 10 per cent, in mixture with ores free from titanic acid, since by so doing the mixture would contain onty 0.50 per cent, of titanic acid, an amount present in the charges of a number of blast-furnaces we could quote, and immense deposits of excellent ores thus be made available as blast-ftir- nace stock.

But prejudices are difficult to eradicate when they are deeply rooted, even if arithmetic is resorted to to demonstrate their fallacy.

There is another objection, more specious than real, which has been raised against the smelting of titaniferous iron-ores, namely, that of the relative economy offered. There is no doubt that, with such ores as were used in England at Norton- on-Tees, and which contained only 36 per cent, of iron with 40 per cent, of titanic acid and 10 per cent, of other gangue (in all, 50 per cent, of barren materials), the addition, as flux, of as much lime and as much silica as there was titanic acid in the ores, there must have been about 4J tons of slag to melt per ton of iron smelted, and the process may not have proved economical as to fuel ; but would it have been any more so with ores free from titanium but containing such an amount of gangue and 40 per cent, of silica ? In the Adirondacks, the ores being much richer and containing so much less titanic acid (15 per cent, instead of 40 per cent), the addition of rock as flux did not very materially affect the economy ; but in our small furnace at Buffalo, as no other flux but dolomite was added (the titanic acid being treated as so much silica), the smelting proved as economical (as the record of the run showed) as that of any other ore free from titanium and con- taining the same amount of silica as the Adirondack ores con- tained of titanic acid.

But this question of economy of fuel, even assuming it were real when dealing with such ores as we might contemplate smelting without admixture, that is, rich ores containing a mod- erate amount of titanic acid, is of but little importance, if, as

Thb Metallurgy Op Titanium. 187

we shall presently see, the properties of the pig-metal yielded by this class of ores are such that it commands a much higher price on the market than an ordinary good foundry-iron.

It is the consensus of opinion, admitted even by those most obstinate in their prejudices, that the pig-iron smelted from really titaniferous ores smelted alone, or in important propor- tions with other ores, is " strong," " wonderfully good," " a splendid iron," " all that can be desired," for such are the ex- pressions met with at every step when one is referred to the literature of the subject. The iron made at Norton-on-Tees in 1869-1876, it is said in the Journal of the Iron and Steel Insti- tute "went to Sheffield for armor-plates on account of the toughness that this iron not only possesses but imparts to others in admixture."

It is essentially an open-hearth stock. Analyses of the pig- iron made by us at Buffalo and that of the Adirondacks (the same ores were used in both cases) showed phosphorus, traces ; silicon, 0.11 to 0.18 ; carbon, from 1.86 to 8.50, practically all combined ; the fracture had very much the appearance of that of steel. It is eminently a chilling-iron, well adapted for car- wheel mixtures. Introduced in such mixtures, not only does it increase the strength of the metal constituting the body of the wheel, but it gives at the tread a deep, strong and hard chill, resisting attrition and shocks remarkably well, as was attested by parties interested in this line of manufacture, and for whom and with whom we have made extensive tests with this special iron.

Briefly stated, the results were as follows : The addition of 5 per cent, of titaniferous pig to a normal mixture for wheels increased the chill on chill-blocks from 1.062 inches to 1.875 inches, and the transverse strength from 3250 pounds to 3775 pounds per square inch. The addition of 10 per cent, of titanif- erous pig brought the chill to 1.562 inches, with a transverse strength of 3600 pounds per square inch ; and the addition of 25 per cent, of this titaniferous pig, white or mottled white as it was, without affecting the original strength, raised the depth of chill to 1.750 inches.

In another establishment the wheel-mixture showed a tensile strength of 24,500 pounds, and a transverse strength of 2500 pounds per square inch. The addition of 10 to 15 per cent, of

188 The Mbtallurqt Of Titanium.

titaniferous pig to a cheap grade of foundry pig, showing only 18,500 pounds tensile strength and 1900 pounds transverse, raised the strength to 25,500 pounds and 2780 pounds, respec- tively, per square inch, with a much deeper chill than in the wheel-mixture, and at a cost of several dollars less per ton.

Strange as it may appear at first, this titaniferous pig-iron does not contain titanium to any important extent. Rarely does it contain more than a few tenths of 1 per cent. ; more generally only a few hundredths of 1 per cent. The influence of titanium in the smelting would seem thus to be one of puri- fication, by eliminating obnoxious elements, more than a direct one ; but we shall see later on that it is not necessarily always so. Titanic acid is not reduced by carbon at the temperature attained in a blast-furnace, contrary to what happens with sili- con. It requires the high heat of the electric furnace to secure such a reduction. If titanium is found in the pig-iron, to some small extent it is due to certain special reactions, pos- sibly to the presence of alkaline cyanides formed in the vicinity of the tuyeres, forming small quantities of cyano- nitride of titanium, which, is carried out by the iron, coating it superficially as has been observed in some furnaces, and giv- ing to the pig-metal a copper-colored hue. This may possibly explain why titanium is found in such small percentages, and why it is not found in the free metallic state in the analysis, but as carbide and cyano-nitride, or both. That titanic acid is not reduced directly by carbon in the blast-furnace, and, if at all, but to a very small amount, seems to be proved by the fact that ores containing as much as 40 per cent, of titanic acid yielded a pig-iron containing titauium 0.00 to 0.03 per cent, (analysis of pig-iron smelted from ilmenite, made at the School of Mines of Paris), while the pig-iron smelted from the Adirondack ores containing 13 to 15 per cent, of titanic acid (TiO,) analyzed 0.07 to 0.12 per cent, of titanium. The conditions of running of the furnace in both cases seem to have had more to do with the reduction, small as it was, than the percentage of titanium in the ores.

The question suggests itself: Since pig-iron smelted from titaniferous ores, though containing but very small amounts of titanium, and that not in the metallic state, but as carbide or combined with nitrogen and carbon as cyano-nitride, what

The Metallurgy Of Titanium. 189

would be the eflTect of the presence of titanium as metal, in more important percentages, in such products as cast-iron or steel?

We know that nickel added to steel, to the extent of 3 to 5 per cent, imparts to it valuable properties; that added even ta cast-iron it increases the strength, though at a material increase of cost. We know, also, that chromium and molybdenum have special influences on the properties of steel. Could not titanium, as a metal, impart valuable though different or similar properties ? But since pig-iron does not appear to contain ti- tanium to any available extent, and the amount present is not in the form of free titanium, and since, whatever this' quantity may be, it disappears in the process of refining pig-iron for mak- ing steel, the only way to secure the presence of titanium to any important extent in pig-iron or steel is to add it to the finished product in the state of alloy, as ferro-titaniumy in the same manner as ferro-chrome or ferro-nickel or ferro-manganese is used to incorporate these metals in steel. Such alloys we have manufactured last year by the ton, and of this manufacture we will now briefly speak :

Professor Moissan, in his well-known experiments on the re- duction of refractory metallic oxides, has been able to obtain small quantities of metallic titanium by the reduction of puri- fied rutile (titanic acid, TiOJ by carbon, in a lime or magnesia crucible, under the influence of the heat secured by a powerful electric current. Moissan's method of using a small furnace, with horizontal electrodes, between which the electric arch was started above the materials to be reduced, and not in contact with them, has become classical. But the product obtained contained carbon, and was indeed carbide of titanium for a great part, and had to be purified by repeated treatment with fresh quantities of titanic acid. Such experiments, although of great interest in the laboratory, could not, of course, form the basis for the production of commercial titanium alloys, as the low price of a product is a sine-qua-non of its practical use. Furthermore, titanium carbide, as obtained by Moissan experi- mentally, on a small scale, and which can be obtained on a larger scale much more easily than the metallic titanium, con- tains titanium combined with carbon in definite proportions. It has special properties, principally of hardness, which it may

190 The Metallurgy Of Titanium.

impart to raixtures ; but however valuable these may be, they are quite different from such properties as could be expected from titanium introduced in a metal (such as cast-iron and steel) in the free metallic state, as is nickel, for instance.

By the method we have followed we have manufactured alloys of titanium and iron containing from 10 per cent, to 76 per cent of titanium, and either practically free from carbon or, if containing carbon, containing it in the graphitic state; so that the titanium was present as free metal alloyed with iron, and not in the state of carbide.

As the percentage of titanium in these alloys increases, their fusibility diminishes. Thus, 10-per-cent. titanium alloys do not melt at the temperature of fusion of cast-iron and steel, and they are incorporated in the molten mass by a sort of dis- solution, just as platinum, infusible at the above-mentioned temperatures, " will fuse in contact with steel at a temperature at which even the steel itself is not affected, alloying in all proportions with iron," as shown by the results obtained by Faraday and Stoddart. Ten-per-cent. titanium alloys contain- ing carbon (graphite) present the appearance of a No. 1 graphitic pig-iron, the particles of graphite shining brilliantly through the mass ; they are soft under the hammer, forging and flattening, though quite resisting. However, when once torn apart, so to speak, in small fragments, they flatten to such an extent as to admit of their being easily pulverized. The powder, sifted through an 80-mesh sieve, showed by analysis the same percentage of titanium as the solid piece itaelf, thus demonstrating a very even dissemination of the graphite through the mass. As the percentage of titanium increases, the grain of the fracture becomes closer, the other characteris- tics remaining the same.

The titanium alloys, free from carbon, are of a silver-white color, exhibiting a coarse crystalline structure, when the tita- nium is low (about 10 per cent.), the grain becoming finer as the titanium percentage increases. With 86 per cent, of titanium the fracture is that of a solid mass, showing no crystallization, at least to the naked eye. The color is of a dull silver-white when the alloy contains over 45 per cent, to 50 per cent of titanium.

All these alloys, the carbon alloys as well as the others,

The Mbtallurqy Of Titanium. 191

are much lighter than cast-iron, their specific gravities varying with the amount of titanium. We have found it to be 5.60 for a 26- to SO-per-cent. alloy free from carbon, and about the same (5.74) for a 10- to 12-per-cent. alloy with carbon ; metallic titanium having a specific gravity of 4.87, cast-iron one of about 7.00, and wrought-iron one of 7.788.

It would carry us too far to describe in detail the manufac- ture of these alloys, and we refer the reader to the article on this subject which has appeared in Vol. IX., Mineral Industry 1901. We will briefly recapitulate its salient points :

The electric furnace we used was of the well-known type of the Siemens furnace of 1879, modified to some extent for our purpose. It consisted essentially of a large block or parallelo- piped of agglomerated graphite. A cavity in the block formed the crucible or hearth ; and in this cavity, by means of a proper system of chains, pulleys, etc., the vertical carbon electrode, or cathode, formed of one or several carbons bunched together, could be worked up and down. The graphite block was con- nected at its lower part with one of the terminals of the cur- rent and formed thus the anode, while the vertical carbon, by means of flexible cables, was connected with the other pole ; the materials to be reduced being charged in the cavity of the furnace,- and the vertical carbon lowered to almost a contact, the arc was started through the materials of the charges, and the reduction proceeded until completed. The product could be removed at the end of the operation, or the alloy (when liquid) tapped off.

According to size of cavity or crucible, intensity of current and percentage of titanium desired, we could make from 150 to 260 pounds of alloy in about two hours with about 200 horse- power. When making alloy containing carbon, the charges consisted of the titaniferous oxides mixed with the proper amount of carbon, the materials being used in powder and strongly compressed. Some of the ores used were the Adi- rondack ores mentioned above, which could yield readily an alloy containing from 12 to 13 per cent, of titanium. By using Canadian ores containing 85 per cent, of titanic acid and about 36 per cent of iron, we obtained alloys containing as much as 36 per cent, of titanium. The use of rutile— natural TiOj-

192 The Metallurgy Op Titanium.

nearly pure, and containing about 90 to 96 per cent, of TiOj, would, of course, have given us alloys as high in titanium as might have been desired; but, until the late discoveries of special, extensive and geologically interesting deposits of rutile in Virginia about one year ago, its cost, $250 to $350 a ton, excluded its use, from the standpoint of economy. Even now, and though rutile has fallen in price to half of what it was, its price is still considerably higher than that of titan- iferous ores high in titanium (40 per cent, of titanic acid), which can be had at the cost of ordinary iron ores.

We have obtained from the Adirondack ore containing 58 per cent, of iron and 15 per cent, of titanic acid (TiO,), or say 9 per cent, of titanium, alloys of 75 to 80 per cent, of titanium by the special method which we have followed, — sort of igneous concentration, as we call it. The method consisted in submitting in our furnaces a mixture of these Adirondack ores with a quantity of carbon sufficient to reduce the iron oxides, but not the titanic acid, it contained, to a heat but a little higher than that attainable in the blast-furnace, adding to the ore a small quantity of lime or good limestone, so as to form practically, with the titanic acid of the ores, a titanate of lime, with such small amount of magnesia and alumina (or silica) as the Adirondack ores could contribute to the slag. We thus obtained, as a by-product, a titaniferous pig-iron, containing but a few hundredths of 1 per cent. (0.032 per cent.) of titanium and possessing all the valuable properties of the metal smelted in the blast-furnace from this class of ores, and at the same time, as slag, a concentrate of the titanic acid of the ore to the extent of 56 to 58 per cent of TiO (corresponding in round numbers to 33 or 35 per cent, of titanium) with no more iron than is ordinarily met in a blast-ftirnace cinder, that is, about 2 per cent. Thus, by treating 100 parts of this concentrate as we did the ore, we could theoretically obtain an alloy containing, say, 31 parts titanium, 2 parts iron, or 94 per cent, titanium ; or, by mixing it with proper quantities of iron-ore, secure an alloy containing any percentage of titanium desired. But, as we shall see, this concentrate proved of particular value in the making of alloys free from carbon.

All the alloys made with carbon, as reducing agent, contained from 7.50 to 8.50 per cent, of carbon, and occasionally even 9 per

The Metallurgy Of Titanium, 193

cent., of which 0.10 per cent, or less was combined carbon, the remainder graphitic carbon. In order to obtain alloys free from carbon, or practically so, we used a method based on the well-known property of aluminum to reduce metallic oxides. This property has formed the subject of many experiments in the laboratory for over fifty years ; but it has been considered necessary, for success, to use the aluminum in the form of an impalpable powder, and to mix it, in that state, with the pow- dered oxide to be reduced.

In recent years Dr. Goldschmidt has succeeded in utilizing industrially, to a certain extent, the reducing power of alumi- num in pulverulent form. His method consists, after having mixed intimately together the powdered aluminum and the powdered oxide, in placing in the mass a primer formed of powdered aluminum and an oxide capable of readily yielding a portion of its oxygen, such as sodium or barium peroxide, and starting the primer itself by igniting an inserted ribbon of magnesium. The heat of formation of alumina (in the primer), the aluminum oxidizing at the expense of the oxygen of the oxides, is so intense that, by contiguity, it is imparted to the whole mass, and the reduction proceeds instantaneously, so to speak, often tumultupusly and dangerously so, without the intervention of any external heat. It is not for us to discuss the value of this process any further than to say that the rapid- ity of the reaction itself creates in the metal or alloy obtained a certain uncontrollable amount of aluminum which cannot be removed without a remelting of the product, and that some of the materials of the vessel in which the operation is carried on also pass into the product — silica, if a clay vessel be used ; carbon, if a graphite one be resorted to ; it cannot be claimed that strictly pure alloys or metals are produced. But the main drawback to its industrial use on a large scale, aside from the manipulations required, is the original cost of the aluminum in powder, which is several times that of aluminum in ingots or scrap.

We have found that it is not necessary to use the aluminum in powder to secure the reducing action, but that if a bath of aluminum be maintained at the proper temperature, in an elec- tric furnace, for instance, like the one mentioned above, the metallic oxides (in this case the titanic acid and the iron oxides

Vol. Xxxiii. — 13

194 The Metallurgy Of Titanium.

charged in the bath) will be reduced, the temperature rising from the heat of formation of alumina to such an extent as to allow the moderation of the external source of heat first applied until the reduction is complete, or nearly so. The metal or alloy obtained can then be kept liquid by increasing the inten- sity of the current before being tapped, and easily deprived, by a fresh addition of oxide of iron, of the aluminum it may con- tain, or by proper additions, of any other impurities it may be considered desirable to remove.

Furthermore, in the Goldschmidt process, if titaniferous iron-ores are used as raw materials, the amount of powdered aluminum to be added must be such as to reduce also the oxides of iron, which is paying rather dear per pound of iron reduced (as it requires nearly one-half pound of aluminum per pound of iron), and if rutile be used, then its price comes in as a very important factor.

By using, in starting, the titanic concentrate mentioned above as containing about 30 per cent, of titanium and only 2 or 8 per cent, of iron, we have to add aluminum to reduce the titanic acid only, and if lower alloys are wanted, dilute, so to speak, the high alloy obtained, in a bath of iron. In this way we have manufactured alloys of titanium containing from 10 to 75 per cent, of titanium and from 0.10 to 0.60 per cent of carbon, or thereabout, at a cost not materially higher than for carbon alloys.

In the tests we have made of the titanium alloys for season- ing cast-iron, we have invariably used the carbon alloys, and, hy preference, alloys containing 10 to 18 per cent, of titanium. In an experiment with steel we have used the alloys reduced with aluminum and practically free from carbon.

We have added the carbon alloy to cast-iron in the crucible in lumps ; in the ladle in small pieces or in powder; in the cupola in large lumps, and also in powder, and the results have been practically the same. An addition of 2 to 3 per cent, or there- about of a 10-per-cent. titanium alloy appears to be amply suf- ficient to secure such results as an increase of 20 to 30 per cent, in the tensile strength of cast-iron, and proportionately as much in transverse strength. Results of such tests have ap- peared in papers read by us before the American Society of Mechanical Engineers (Milwaukee Meeting, May, 1901, Vol. XXII. of Transactions) and at the Annual Meeting of the

The Metallurgy Op Titanium. 195

American Foundrymen's Association, June, 1901, Buffalo (Vol. X., Transactions Part I.), to which papers we refer the reader.

Since then we have made other equally successful tests in different establishments, car-wheel works and others. We will briefly recapitulate them :

In general, the results of tests of 100 square bars 1 by 1 by 12 inches between bearings, and round bars in. in diameter by 18 inches in length, or thereabout, showed that by adding in the cupola, in good-sized lumps, 8 per cent, of a 10-per-cent. alloy, or the same amount in powder in the ladle, we could bring the original strength of a good No. 2 coke-iron, showing 24,500 pounds tensile and 2450 pounds transverse strength per square inch, up to that of an excellent Scotch charcoal pig-iron or higher (in fact, 28,800 pounds tensile and 2900 pounds transverse); and that by a similar addition of alloy to this Scotch charcoal pig we could bring the strength to some 82,- 500 pounds tensile and nearly 3800 pounds transverse strength. As the price of this charcoal pig-iron was $29 a ton, while that of the coke-iron was $15 at the time, and as they were used in mixture for special foundry purposes, it is clear that a mixture of the coke-iron treated with the alloy and of the coke-iron itself not treated could be used with great advantage as to cost of mixture for the same strength secured ; the addition of the alloy to the extent mentioned to the coke-iron increasing the cost of the latter but a fraction of the difference of prices ($15 and $29) between the two original pig-irons.

Our tests with steel have so far been limited to crucible steels, and enough has been observed to show that the influence of titanium, introduced into steel in the metallic state, has been to increase considerably the ductility, as proved by the remark- able elongation, contraction of area and limit of elasticity ob- served in high-carbon steels containing 1.25 per cent, and even 2 per cent, of carbon. The quantity of titanium found in the steel by analysis varied from 0.89 per cent, and 1.01 per cent, to 0.10 per cent. As the effect of even such small quantities as the latter (0.10 per cent.) was very marked, and as, in these cases, 0.10 per cent, did not represent what could have been expected from the addition of the alloy, the question arises : Has not titanium, when thus added to steel, an indirect action besides a specific one ?

196 The Metallurgy Of Titanium.

It has been suggested that, in the same manner as manganese removes oxygen from steel in the Bessemer process, and also in the open-hearth and even in crucible steel, titanium may act not only as a deoxidizing agent, much more powerful still than manganese, but may also remove from the steel the nitrogen it undoubtedly contains, and which has an unfavorable influence on its strength. (The odor of ammonia so noticeable in the open-hearth process proves the presence of nitrogen very de- cidedly; and as is well known, titanium burns in nitrogen at 800° C. with incandescence, just as iron burns in oxygen.) If this is so, a use for the alloy, even when containing carbon, might well be found in the open-hearth as also in the converter, since it could be used as a recarburizer, on account of the high percentage of carbon it contains ; as a deoxidizer (with or without ferro-manganese) ; and as a denitrogenizer, so to speak ; and, in the case of small converters for steel castings, the heat of formation of titanic acid, which is much higher than that of silica, would prove of advantage in raising the temperature of the bath even were but a small percentage of titanium to re- main ultimately in the finished product. If by such use open- hearth and converter steel could be so improved as to compare better as to strength with crucible steels, and the latter be also improved to the extent it appears to have been in our first tests, there would be opened for these alloys a large field of use- ftilness, and for these titaniferous ores a very important appli- cation.

In tests made in some establishments we have used simulta- neously the titaniferous pig and the alloy in the cupola, with such a resulting toughness combined with a remarkable hardness and strength of chill in car-wheels that it has justified the statements of some manufacturers as to the importance of these products in the iron industry, when better known. To obtain them cheaply — and we mean by that at such a price that their use would prove economical in view of the results secured — has been our aim.

We may remark here, that if the thickness of a casting can be diminished without impairing its strength — on the contrary, leaving it stronger — the cost of the material which has secured such a result may well be compensated for, and more, by the advantages obtained.

Manganese Industry Of Department Of Panama. 197

We are continuing our tests along these lines for different establishments, and we may be justified in saying, as a conclu- sion, that if these tests and those carried on by outside parties (to whom we are willing to extend all facilities to make them), justify our claim, as those already made have done, the im- portance of the metallurgy of titanium cannot be ignored or overlooked much longer, and that these titaniferous ores, as we said at the outset, will constitute a valuable resource and reserve for the future, both for blast-furnace stock for the man- ufacture of pig-iron and for metallurgy in general for the pro- duction of valuable alloys. Titanium may be found to form alloys with other metals than iron, or with iron and other metals possessing special and valuable qualities. We have had no trouble, by following our aluminum method, in making alloys of titanium and copper, as well as ferro-tungsten, ferro-chro- mium, ferro-molybdenum (practically free from carbon), and compound alloys of chromium-titanium-iron, etc., of which we are now studying the properties.

The Manganese Industry of the Department of Panama, Republic of Colombia.

BY E. G. WILLIAMS, COLON, COLOMBIA, 8. A. (New Haven Meeting, October, 1902.)

General Description.

Manganese-ore has been found upon the Isthmus of Panama throughout a region of nearly three hundred square miles, over the greater part of which, however, it is known only in small bodies without commercial value.

Only six mines, controlled by two companies, have actually shipped ore, although a large area has been taken up in mining- claims.

The ore-bearing region extends along the coast of the Carib- bean Sea, beginning on the west near Puerto Bello and extending easterly about 85 miles toward Point San Bias. Ore has been discovered in the interior, at a maximum distance of about 10 m. from the coast. Fig. 1 is a map of a portion of the Isthmus

198 Manganese Industry Of Department Of Panama.

of Panama, compiled from the map of Lucien N". B. Wyse, pub- lished by the Panama Canal Co., from Government charts, and from surveys of the Caribbean Manganese Co., and showing the manganese-bearing area and the location of the working mines.

The last known ore-deposit to the east is upon the border of the country of the San Bias Indians ; and further prospecting in that direction is at present impracticable, on account of their hostility toward strangers. It is probable that the boundaries of the ore-bearing area given above may be <;onsiderably ex- tended by future work.

The first shipments from the region were made in 1871, from the village of Viento Frio. This early mining was of a primi- tive character, and consisted in breaking up surface boulders near the sea and packing the ore down to the coast upon men's backs. Probably 1000 tons of ore was shipped in small ves- sels, mostly to England, between 1871 and 1875, when the loss of a schooner near Viento Frio cstused the abandonment of the work.

In 1880 the manganese properties in the immediate vicinity of Viento Frio were acquired by Mr. W. L. Rathburn, now of Xew York City.

Mr. Rathburn worked the property for about a year, ship- ping small lots of ore in schooners, which he had engaged in the cocoanut trade between the Isthmus and New York. The largest shipment was one of 80 tons. This, however, never reached its destination, the schooner foundering at sea.

A shipment to England of 40 tons of high-grade ore showed on analysis 57.87 per cent, of metallic manganese.

The ore shipped to the United States was ground and sold for chemical purposes.

The ore in sight at that time consisted entirely of surface boulders. An examination of the property by an English engineer engaged by Mr. Rathburn failed to show any suit- able ore reserve ; and, acting upon the engineer's report, Mr. Rathburn disposed of the property.

The persons who acquired it did not attempt to mine any ore, and nothing further was done until 1890.

Then the discovery, upon the surface about 5 miles south of

Manganese Industry Of Department Of Panama. 199

200 Manganese Industry Of Department Of Panama.

Viento Frio, of large boulders of high-grade ore, which had been unknown to the early miners, caused a revival of interest in manganese-mining in the locality, and led to the formation of the Caribbean Manganese Company of Baltimore to exploit the deposits.

In 1894 and 1895 the Caribbean Manganese Co. constructed, from the shipping port of Nombre De Dios to the base of the range upon which its principal mine was located, a railroad of 8-ft. gauge, nine miles in length, with maximum grades of 5 per cent, in favor of the traffic, and maximum curves of 40 degrees.

Aside from this company, the only shippers from the region have been the firm of Brandon, Arias & Filippi. The Carib- bean Manganese Co. has shipped ore from four properties — the Viento Frio, Carano, Concepcion, and Soledad. The firm named has shipped from the La Guaca and Culebra mines. All the mines mentioned are near the railroad ex-cept Culebra, which is situated upon a small island about 12 miles east of Nombre De Dios. Some ore has been mined at Meamar, about midway between Nombre De Dios and Culebra, but none of it has been shipped. Fig. 2 shows the location of the mines adja- cent to the railroad.

The total product of the region to date has exceeded 60,000 tons. On account of the revolution in the country, the work has been conducted under great difficulties during the last two years, and at times has been entirely suspended. The restora- tion of peace will undoubtedly cause a revival of interest in mining throughout the entire country.

The earlier history of manganese-mining in this region has been fully given by Mr. E. J. Chibas in a paper presented be- fore the Institute in 1897,* and the present paper deals mainly with later developments.

Topography op the Manganese Region.

On entering the Isthmus of Panama, the Western Cordillera of the Andes, which follows the Pacific coast-line of Colombia, divides into a series of parallel ranges which reach a maximum

Trans., xxyii,, 63.

Manganese Industry Op Department Of Panama. 201

height of about 3000 ft. Fig. 1 shows in the region of the ore-deposits a series of parallel rivers on the Atlantic side, flowing north into the Caribbean Sea; on the Pacific side a series of parallel rivers flowing south into the Pacific Ocean,

Fig. 2.

MAP 5HOWING LOCATION OF MINES- CARIBBEAN MANGANESE CO. 5C/M.C r- 8oo'

while the center of the Isthmus is drained by the Chagres and its tributaries, flowing in this portion of their courses in a general westerly direction.

In general, the manganese-deposits are found within the

202 Makganbsb Industry Of Dbpaktment Of Panama.

draiuage-areas of the first set of rivers mentioned, flowing- north into the Caribbean ; although in one instance, at least, a considerable deposit exists within the Chares drainage-area.. All the ore-deposits are upon the Atlantic slope.

At some points within the manganese-bearing area the high- land approaches the sea, but often (as around Nombre De Dios)- lowland, enclosing swamps and lagoons, extends back from the shore a quarter of a mile or more to the foothills.

The hills rise in a series of parallel ranges, each higher than its predecessor, toward the interior, and the country is very rough and diflBcult of access. No roads of any description exist; and the usual way of reaching the interior is to paddle up a river as far as a canoe will float, and then wade up in the river-bed to the head of the stream.

The surface-rock has been decomposed to a considerable depth, and the heavy rainfall upon the resulting clay mantle which covers the country has aflforded great opportunities for the modelling of the surface by erosion. After a few hours of mountain climbing in the interior, one is usually convinced that Nature has taken full advantage of these op- portunities. The streams, except for short distances near the coast, flow in narrow gorges with steep side-slopes, which stand at practically the angle of repose of the surface soil. This is shown, apart from the slope angle, by the numerous landslides after heavy rains, when the soil is saturated to a greater degree than usual. The summits of the divides between the streams are often so narrow as to allow only a footpath upon them.

The manganese-deposits occur upon the comparatively low lands near the sea as well as upon the summits of the hills in the interior, and the Culebra mine is upon an island — a rem- nant of the mountain spur which here approaches the sea.

Rocks Associated with the Ore-Deposits.

The clay which everywhere covers the surface makes the work of tracing the formations very difficult. Occasional out- crops, through the clay, of rock hardened by metamorphic action, furnish the only evidence.

The rocks immediately associated with the manganese- deposits are all sedimentary formations, but are now so greatly decomposed as to render their original character doubtful,

Manganese Industry Of Department Of Panama. 203

though, when first formed, they were probably shales. In the vicinity of some of the ore-deposits they have been metamor- phosed into a jasper, and thus preserved.

In the bed of the Mamey river, skirting the base of the Sole- dad mountain, upon which the principal ore-deposit of the re- gion is located, occurs the only rock in the vicinity of any such deposit which appears, even at first sight, to be of igneous ori- gin. But this, upon microscopic examination, proves to be a metamorphosed sedimentary rock, composed of a mixture of volcanic ash and particles of other sedimentary material, ap- parently derived from the decomposition of an andesite. The rock is highly silicified, and also decayed by weathering, thus making its determination somewhat difficult.

The surface-days are usually light yellow. Where associated with ore in place, however, the clay is generally bright red ; but it is found in all shades from red to white, the varying colors resulting from the various stages of oxidation and hydra- tion of the manganese and iron contained in the clay.

The rocks associated with the ore will be described in greater detail in the description of the various mines. The writer is indebted to Professors S. L. Penfield and L. V. Pirsson, of Yale University, for assistance in the rock-determinations.

Character op the Ore.

The ore occurs as oxides. The principal variety, furnishing the greater part of the commercial ore, is psilomelane. Pyro- lusite and braunite also occur. The psilomelane and pyrolu- site are intimately associated, one oxide blending into the other without any visible line of separation. It is not uncommon to find in massive psilomelane small cavities filled with pyrolusite, and clusters of pyrolusite crystals have been found radiating from a base of psilomelane. The psilomelane is massive and very hard. It varies in color from black to steel-gray, the steel-gray ore being usually the hardest, and having a con- choidal fracture. The massive psilomelane in large bodies shows numerous fracture-planes (slickensides), and the two adjacent surfaces are often hardened above the general hard- nesB of the ore for a depth of one or two inches, so that it is extremely difficult to temper drill-steel so that it will stand work in them.

204 Manganese Industry Op Department Of Panama.

The ore classified as braunite is of infrequent occurrence, and consists of small masses made up of numerous small crys- tals, the whole showing a well-defined crystalline structure, with an irregular fracture. The crystals are iron-gray in color, the color resembling the steel-gray of the massive psilomelane, but not having so brilliant a metallic luster on a fresh fracture. The pyrolusite occurs in fibrous crystals, usually about one-half in. in length, radiating in clusters from a massive base. It also occurs as a granular mass, made up of numerous small crys- tals. As a source of commercial ore it is not important. Of the crystalline ores, pyrolusite belongs to the orthorhombic system of crystallization, and braunite to the tetragonal.*

An analysis received by the writer jast at the time it was necessary to send this paper to the United States for publication raises a presumption that a portion, at least, of the hard, massive ore described throughout this paper as psilomelane may prove to be a hitherto undiscovered manganese oxide, having the formula Mn0.2MnO„ or MnjOj.

Some samples of the purest ore of the Soledad mine were sent to Prof. S. L. Penfield, of Yale University, for a complete analysis, to accompany this article, as representing the character of the high-grade ore of the region. The ore was supposed to be psilomelane, which in appearance it resembles.

The analysis was made by Mr. W. E. Ford, assistant to Prof. Penfield, and gave the following result, as the mean of two analyses which ciieck each other very closely :

Manganese protoxide (MnO), 78.25

Available oxygen (O), 11.83

Copier oxide (CuO), 0.67

Quartz (SiOj), 2.00

Soluble silica (SiO), . . 2.67

Iron sesquioxide (FeaOg), 0.40

Alumina (A1A) 0.21

Lime (CaO\ 1.32

Magnesia (MgO), 0.16

Potash (KjO), 0.10

Soda(Na20), 0.38

Water (H.,0), 1.70

Phosphoric acid (PPs), 0.03

Metallic mangnnese, 60.60

Mr. Ford remarks, concerning the analysis :

If all the available oxygen in the ore is calculated as belonging to MnOj we should have 64.32 per cent, of MnOj and 25.76 of MnO. If we consider it in this way, we have the ratio of MnO. : MnO as 0.739 : 0.363 or as 2.00 : 0.98, which equals very nearly 2 : 1. Under this assumption the manganese oxide of the ore has the following formula : MnO.iMnOj, or MnOj. If, on the other hand, we <calculate the manganese in the ore as occurring in the form of MnOa. we have 87.06 per cent, of MnO., and an excess of 3 per cent, of oxygen.*'

Manqansse Industry Of Department Of Panama. 205

The physical features of the ore vary greatly, and the differ- ent oxides apparently blend in all shades of gradation, so that it ie nsaally difficult to identify the mineral species when it is ancrystallized.

Pockets of soft ore, which can be worked without drilling, are sometimes, but not often, found in the hard ore-bodies. Bodies of red clay and ore, interstratified, are found ; and ore is also found, but rarely, interstratified with jasper. Occasion- ally, small masses of concretionary origin occur.

Some of the mines show massive ore almost entirely; in others the ore shows plainly a stratified structure, in which case it is osaally of somewhat lower grade than the massive. Where metamorphic action has taken place (as shown by the conversion of the shale to a jasper), the ore is almost invariably massive ; and the stratified form, on the other hand, is almost invariably found with the unaltered shale. Hence the massive form it prohably the result of a consolidation of the stratified masses by metamorphic action. The higher grade of the massive de- posits is probably due to secondary chemical changes. Where manganese oxide which has been subjected to metamorphic ac-

Prof. Penfield, writing of the mineral, sajs :

''The mineral is not like taiy of the well-known manganese species. It is hard, like psilomelane, hat contains too little water and too little oxygen. Leav- in|( the small amount of water out of consideration, the mineral agrees very well with the composition Mn0.2MnO,, or Mnfi The close agreement with the formula may he in part accidental, as the material is not crystallized ; hut, if the specimen sent represents a fair sample of what you are mining, my helief is that joo are at work on an ore which deserves a name as a distinct mineral species."

Prof. Penfield also calls attention to the somewhat similar composition of chal- cophanite, a hydrous oxide of manganese and zinc, found at Franklin Furnace, X. J., the composition of which, as given hy Dana, is (MnZn)0.2Mn02-2H20. In this mineral the ratio of (MnZn)O to MnO, is the same as that existing in the Apecimens analyzed from the Soledad mine. In the analyses of chalcophanite gven hy Dana the proportion of MnO to ZnO is ahout 1 : 3. But for the rephicement of part of the manganese hy zinc, chalcophanite could be considered a hydrous form of the oxide described above. Additional samples of the purest ore ohtainable have been sent to Prof. Penfield for a more detailed examination. As the existence of a new manganese oxide cannot be considered as fully estab- lished by the two analyses made, and as the results of further investigations now in progress mu.<it be awaited, the designation of the massive ore ns psilomelane, preTiotisly adopted, has not been changed, especially as psilomelane does occur in the region as a common ore, and the similarity in appearance between it and the new oxide would allow the same general description of physical characteristics to apply to both.

206 Manganese Industry Op Department Of Panama.

tipn is of high grade, or at least is low in silica, it is to be inferred that a low temperature accompanied the change, since, under a high temperature, the ore would have taken up silica from the surrounding rock. There is but little difference in the siliceous contents of the massive and the stratified ore of the region, the former being slightly higher in silica, and also in manganese.

The ore usually requires hand-picking, to keep the silica con- tents below the allowable limit of 8 per cent., above which the ore has to pay a slight penalty for each additional unit of silica. The siliceous ore is easily recognized by its appearance. The ore is low in phosphorus, never exceeding in the massive form 0.07, and usually, in cargo-lots, running below 0.05 per cent - In the stratified form the phosphorus contents usually run a trifle higher than in the massive ore, but never exceed 0.09 per cent.

The different ores will be described in more detail, and anal- yses given, under the descriptions of the several mines.

The Mines of the Caribbean Manganese Company. The Soledad Mine.

This mine, the most important of the region, is about 6.5 miles in a direct line, or 9 miles by railroad, SE. of the port of Nombre De Dios. The first discovery here was of large and small boulders of manganese-ore scattered over the westerly and northerly slopes of the Soledad mountain. Large quantities of ore were in sight upon the slopes of four small streams that head upon the mountain and flow into the Mamey river, as also in the river itself where it skirts the base of the mountain. The boulders were all upon the surface, or at slight depths below. The surface-soil was yellow clay formed from the de- composition of a shale. In shallow excavations the clay became harder, and the original lines of stratification were usually vis- ible, although the decomposition extended to a much greater depth. The boulders of manganese were invariably contained in the thoroughly decomposed surface-rock, and extended in- vestigation failed to show any ore in the lower strata.

It was at first believed that these boulders represented dis- tinct pockets of ore, originally contained in the shale, some being still in their original position, surrounded by the clay formed in situ by the decomposition of the shale, while others

Manganese Industry Of Department Of Panama. 207

had been left exposed upon the surface by the erosion of the <5lay, or naturally concentrated, after such erosion, in the beds of the streams. In some portions of the Panama region, as in other manganiferous areas where the ore is found in scattered masses with no apparent source of origin, it is undoubtedly true that each boulder was originally a distinct ore-pocket in the containing rock, or, at any rate, was first contained in the rock in the remains of which it is now found. The ore comprising the boulders in these cases was probably contained in the orig- inal rock generally in small particles, and, on the decomposition of the rock, large masses were formed by the resulting ore-con- centration and the action of surface-waters charged with man- nese oxides and carbonates.

The difficulty of applying this theory to the Soledad boulders lay in the fact that they were all contained in the completely decomposed rock on the surface, while the same rock at a small depth contained only traces of ore. This fact, combined with confinement of the boulders within a fan-shaped area converg- ing toward the mountain summit, and the angular form of many of them, which seemed to indicate that they had been recently broken oft' from larger masses, led to a thorough exploration of the upper portion of the mountain, upon the theory that the boulders were " float " from a parent deposit above. The discovery in 1896, and the subsequent development, of a large body of ore in place nearly upon the summit of the mountain, about 700 ft. above sea-level, proved the truth of this theory.

The contour-map. Fig. 3, shows the topography of the Soledad region, and the manner of occurrence both of the ore in the parent-deposit and of the float. More than 10,000 tons of high- grade ore were obtained from the scattered boulders. In one instance more than 600 tons were secured from one boulder.

At the main ore-body the accompanying rock is a decomposed shale, in many places (especially south of the body) changed to jasper. This rock is highly impregnated with oxides of iron and manganese, and also highly silicified. It varies in color from red to yellow, and shows numerous fracture-planes, often baving afilm of manganese oxide between two adjacent portions. It is also intersected by many small seams of quartz. When the strata are visible, they are often much disturbed and con- torted, afid sometimes thrown into short folds. They are gen-

208 Manganese Industry Of Department Of Panama.

Fig. 3.

Map Showing Topography Manganese Region, Soledad Mine

SCALE r'mOO'

±J.I I I I i III 1 1 1 i I 1 I 1 1

Njote.

COINTOUf CLEV>STlONS ABOVE StA UtVEU. PRCdENCe OF MANOANCSC DOULDCPIS

SHOWN TMU5 + -t + ORE. irPUACt SHOVVN THUS

Manganese Industry Of Department Of Panama. 209

erally tilted from 70 to 80 deg., dipping SW. The general strike of the ore-bearing strata from the coast inland is S. 5° E. Near the Soledad mine, where the first considerable upheaval took place, the strike varies from that shown further north, the strata here following the direction of the range of foothills about S. 70° E.

The ore-bodies generally follow the bedding-planes, being occasionally interstratified with the rock, but usually constitut- ing a series of lenticular or irregular masses, connected by small stringers of ore. A red clay, occurring in large masses within the ore-bearing area, and intimately associated with the ore, probably represents a completely decomposed rock, originally deposited with the ore. In width, the ore-bodies vary from a maximum of about 50 ft. down to a few inches. As they fol- low, generally, the stratification-planes, the unaltered bodies dip about 80 deg.

The rock on the SW., forming the so-called hanging-wall, is a highly silicified jasper, passing by blended gradations in the upper level to the original shale. On the KE. side there is usually a stratum of red clay of variable thickness in contact with the ore ; and a bed of volcanic ash from 2 to 8 ft. thick is next encountered, followed by the shale.

Both the manganese-ore and the jasper show numerous frac- ture-planes, partly caused, no doubt, by the general upheaval of the region, but probably due, in the main, to the subsequent adjustment of the rocks, resulting from the change of volump which followed the secondary concentration and enrichment of the manganese deposit from the surrounding rock.

The Soledad ores comprise braunite, pyrolusite and psilo- melane, — principally the last. The greater part of the ore is massive, varying in color from a steel-gray to a bluish black, and usually showing a conchoidal fracture. It is rarely strati- fied ; but there are some bodies of interstratified soft ore and clay. Pockets of ore, soft enough to be mined without explo- sives, are occasionally, but not often, found in the massive ore.

Fig. 4 presents horizontal sections of one of the principal ore-bodies at various elevations, including (on account of the great irregularity of the ore-body) intermediate points as well as the mine-levels. Fig. 5 gives a longitudinal section of tho same ore-body, and cross-sections are shown in Figs. 6 and 7 ; VOL. .— 14

210 Manganese Industry Of Department Of Panama.

Fio. 4.

NOTt

ELEVATIOfM5 OF StCTIONS ABOVe ftfcA LEVfeU 7'0

S7

St NOT neT&KMlNCD.

B

SOL.EDAD MANGANESE DEPOSIT HORIZONTAU ECTIONS SCALE r-4'

ujf .r .jLLj;

Manganese Industry Op Department Of Panama.

the section-planes being indicated on the plan in Fig. 4. The cross-section shown in Fig. 6 is found only near the outcrop of the ore-body ; and the excess of ore in the upper portion is probably due to a secondary concentration, following weather- ing and partial erosion at the outcrop. A large portion ot the Soledad deposit has been removed by erosion. As already ob- served, more than 10,000 tons of high-grade ore was mined from the float. Nearly 20,000 tons of all grades was in sight

Fio. 5.

90LC0A0 MANGANESE DtPOMT tONOITUOlNAL SECTION ON tlNC (SCI fH.AN).

r.r.T.T

when work began. The plan and sections shown cover only a small portion of the ore-bearing area.

The depth to which the ore extends is unknown. It is seen continuing below the lowest level of the mine, which is about 230 ft. below the summit of the hill. Of this depth, about 110 ft. 18 represented by the underground workings, and about 120 ft. by an open cut.

About 30,000 tons have been mined from the ore in place. This does not include the ore mined from the boulders on the slopes of the hill, which were originally included in the de-

212 Manganbsb Industry Of Department Op Panama.

posit. Including the surface-boulders, upwards of 40,000 tons has been fiirnished by this ore-body.

The best cargo-lot ever shipped from this property was one

Fig. 6.

Soledad Manganese Deposit

CROSS SECTION ON CD ( StE PLAn). 5CALB r- 4-0'

I r.TiTiT.T

of about 1500 tons, which contained, according to sample- analysis, metallic manganese, 57.50; silica, 4.18; and moisture, 2.73 per cent.

MANaANBSB INDUSTRY OF DEPARTMENT OF PANAMA. 213

Fig. 7.

QR<aO!M

Soledao Manganese Deposit Cross Section On Line Ef Cee Plan)

SCALt r-4-o'

L.>l...it I I I T I I I I

214 MANaANESB INDUSTRY OP DEPARTMENT OF PANAMA.

Other large lots, of equal grade within fractional percent- ages, have been shipped. Of the total of more than 40,000 tons shipped from this property, complete analyses are not at hand ; but the average analysis of about 23,000 tons was : me- tallic manganese, 53.74; silica, 8.68; and phosphorus less than 0.06 per cent.

This fairly represents the high-grade ore in cargo-lots. No washing or other preparation is necessary for the best lump ore. It is shipped as it comes from the mine, except that it is hand-picked, to remove the siliceous pieces. The fine ore re- quires washing.

Besides the high-grade bodies, there are large bodies of sili- ceous ore carrying about 47 per cent, of manganese, and from 18 to 30 per cent, of silica. These are not worked at present, but will undoubtedly be utilized hereafter, since the greater part of the silica is not in chemical combination with the ore, and can be removed by crushing and jigging. The percent- age of phosphorus in these siliceous ores is always under 0.075.

Method of Mining. — The discovery outcrop is about 100 ft. below the summit of the hill. An open cut was begun about 20 ft. below the outcrop and carried in until the walls were 100 ft. high. The mountain, rising faster than the ore-body, gave a constantly increasing over-burden to remove; and this, with the difficulty of holding the side-walls, led to the abandonment of open-cut work and the beginning of underground mining in 1898. A tunnel was driven into the ore-body from the open-cut level. From the same level a shaft was sunk 110 ft. and two levels were opened. The mine is drained by a tunnel on the bottom level connecting with the shaft.

The ore is usually stoped for the entire width of the deposit, both heavy timbering and supplementary filling being required. At some points it is necessary to leave pillars of ore in place, to be extracted when the stope is about to be finally abandoned. The ground is difficult to hold, because of the decomposed rocks surrounding the ore and the large masses of clay associated with it. Occasionally a pocket of clay is opened which is under heavy pressure from the surrounding rock or ore. As soon as an outlet is furnished, the clay begins to flow into the stope in a plastic mass ; and great difficulty is often experienced in checking this flow. The most satisfactory method of work-

Manganese Indu8Trt Of Department Of Panama. 215

ing — indeed, the only one by which the soft clay walls can be lield — is to keep the stopes filled to within about 7 ft. of the roof. The ore-shoots and man-ways are built up from the level below, as the filling is carried up. The material for filling, apart from what is furnished from waste in the mine, is obtained outside, on the open-cut level.

Square-set timbering has been used in large stopes, but it has l>een found better and cheaper, where the filling system was employed, to support the roof with cribs of round logs, which accommodate themselves, without damage, to the shrinkage of the newly-filled material and the pressure from the ore.

The ore from the lower levels is hoisted to the open-cut level by a gasoline hoist, which was installed on account of the dif- ficulty of obtaining a supply of water through the dry season. The ore is hand-picked on the open-cut level, the large pieces going direct to the tramway which connects the mine with the railroad, while the small pieces and finely-powdered ore are transported separately, taken to the log washer, and screened after washing.

The size above 0.5-in. mesh is hand-picked and shipped; the finer portion being reserved until a suitable concentrating-plant shall have been erected. This care in sorting the ore is ren- dered necessary by the presence of particles of jasper in the ore, which, if not removed, subject the ore to a penalty for silica.

The ore is stored on the upper level in a 50-ton bin at the loading terminal of a Bleichert tramway. This tramway, about one-third of a mile in length, has its upper terminal 420 ft. above the railroad to which it conveys the ore. At the railroad there is a 300-ton ore-bin, from which the railroad cars are loaded. The tramway is operated by gravity, the descending loaded buckets developing 6 H.P. All mine-supplies, timber, etc., are brought up to the mine on the tramway, which has a capacity of 25 tons per hour.

Hand-drilling was used until the present year, when, on ac- count of the difficulty of obtaining laborers during the revolution in the country, an air-compressor was installed, driven by a 35- H.P. gasoline-engine, and power-drills are now used.

The Concepdon Mine,

The Concepcion mine of the Caribbean Manganese Co. is about 2 m. north of the Soledad. The ore at this point

216 Manganese Inbustrt Of Department Of Panama.

Manganese Industry Of Department Of Panama. 217

was first discovered as boulders in the bed of a small stream flowing into the Concepeion river. A little development showed the boulders to be close to the original body from which they had been derived, the stream having cut through the ore-de- posit. Prospecting in the vicinity led to the discovery of other ore-bodies in place, until, within an area of 1100 by 600 ft., more than a dozen distinct ore-deposits had been found. The map, Fig. 8, shows their relative position. About 12,000 tons has been mined here ; the largest ore-body furnishing about 4000 tons.

The ore is associated with a decomposed sedimentary rock, either interstratified with it, or following, as a series of irregular bodies, the general direction of the bedding-planes. The rock is of the same general character as that surrounding the Sole- dad ore-deposit, except that it shows little evidence of meta- morphic action. The strata are upturned at angles of from SO to 60 deg., and the strike is about S. 3® E.

The ore is usually somewhat lower in grade than the Soledad ore, although, in one of the deposits, more crystallized pyro- lusite is found. In most cases the ore is plainly stratified, nearly black in color, and much softer than the massive ore of the region. There is often a narrow seam of clay between two strata of ore. On account of the clay in the ore, the greater part requires washing.

The ore-deposits often have the general mushroom shape, shown in vertical section by Fig. 9. This is caused by the weath- ering of the upper portions of the upturned strata, the manga- nese being broken up and redeposited over a considerable area, while the stratum of ore lower down retains its original position in the enclosing rock.

The ore is worked both by open-cuts and underground, but none of the workings have reached the depth of 100 ft. The lowest workings are below the bed of the Concepeion river, and there is considerable water to handle. A steam-pump and two hoisting-machines are in operation.

The mine is connected with the railroad by a Bleichert tram- way 5600 ft. long, with a carrying-capacity of 15 tons per hour. The terminals are at nearly the same level, and the tramway is operated by a steam-engine of 10 H.P., located at the discharg- ing terminal. The various workings of the mine are connected

218 Manganese Industry Of Department Of Panama.

with the tramway by a portable railroad-line of 0.5 meter gauge. The ore is hoisted from the pits in buckets holding about one ton each, which are placed upon cars and hauled to the tramway-terminal, where the ore is hoisted and dumped into a 50-ton bin, from which the tramway-buckets are loaded.

The log washer, which serves both mines, is located at the

Fig. 9.

Section Of Ore Deposit

CONCEPCION MINE SHOWING Concentration of orc bv erosion scAuc 4-0'

? '? V 3P 4;0 8tL

discharge-terminal of this tramway. The ore which requires washing is here washed, and then taken to the shipping-port. No screening of the small sizes is necessary, as at the Soledad mine, since the only impurity is a soft clay, which is easily removed by washing.

Analyses of Ore. — Samples of ore from diflFerent deposits on the property gave the following analyses :

MANGANESE INDUSTRY OF DEPARTMENT OF PANAMA. 219 Percent Per Cent. Percent Per Cent Per Cent Percent

Metallic manganese,

. 46.97

Iron,

Silica, .

Phosphoras, .

. 0.083

Lime, .

The analysis in the last column is that of a selected speci- men.

Washed ore in cargo-lots will average nearly 50 per cent, of manganese and about 8 per cent, of silica. In cargo-lots, with- out washing, the ore contains enough clay to reduce the manga- nese contents to 44 per cent, and increase the silica to 12 or 14 per cent.

Transportation and Shipping. — From the bins at the railroad the ore is loaded by gravity into small side-dumping cars, of about 8 tons' capacity, and hauled to the shipping-port. Here it is dumped from a trestle upon the stock-pile. There is storage here, without rehandling, for about 8000 tons. The ore is shipped in steamers which are loaded alongside the Com- pany's wharf. It is loaded into tubs, holding about 1800 lbs. each, which rest on small trucks running on a track of 0.5 meter gauge. There are two endless tracks, one on each side of the ore-pile, extending onto the wharf. The ore-trucks make a continuous circuit, the loaded tubs being hoisted and their contents dumped into the steamer's hold, and replaced empty upon the truck, which then returns to the ore-pile to reload. Each track serves a separate hatch on the steamer ; and the ore is loaded at the rate of 400 tons or more daily.

The Carano Mine.

The Carano mine of the Caribbean Manganese Co. is about 1 m. north of the Concepcion, and about 2 m. from the coast. The geological formation here is similar to that at the Concep- cion mine, and a number of ore-deposits in place have been partially developed. Some of these would yield a consider- able tonnage. The ore is usually stratified, and the deposits lie in bodies parallel to the bedding-planes of the rock, except where they have been concentrated on the surface by erosion and weathering. The strike and dip of the stratified rocks is the same as at the Concepcion.

220 Manganese Industry Op Department Of Panama.

About 200 tons of ore was mined here in 1892, and trans- ported to the coast on pack-mules ; but lack of transportation facilities have prevented any extensive operations since.

The ore is of the same general character and grade as that of the Concepcion mine.

Viento Frio Mine.

This mine, belonging to the Caribbean Manganese Co., is about 1.25 m. north of the Carano, and near the coast. No large ore-deposits in place have been found at this point, as at the mines previously described. The ore occurs as boulders in a fitiff clay, varying in color from red to white. The country is comparatively level ; and these boulders are probably the rem- nants of a stratified deposit obliterated in the wearing down of the surface.

As some of the boulders show a stratified structure, and as their location is directly upon the strike of the formation pro- duced north from the Carano mine, it is probable that they are the remains of an ore-deposit similar to those previously de- scribed. It is, of course, possible that the boulders were origi- nally contained, largely in their present form, in the rock from whose decomposition the clay was derived ; but the history of the other deposits of the region and the stratified form of the T)oulders make the first supposition more probable.

About 1500 tons has been mined at this point, the greater part between 1870 and 1873 by the early miners, and the rest since the acquisition of the property by the Caribbean Manga- nese Co. The ore is similar to the Carano and Concepcion ores. Here, as at the Carano mine, lack of transportation facilities has prevented any extensive work.

Mines op Messrs. Brandon, Arias and Filippi.

La Guaca Mine.

La Guaca mine, of Brandon, Arias and Filippi, is about 2 miles northwesterly from the Soledad mine.

The ore occurs in large and in small boulders originally ex- posed in the beds of the streams and upon the adjacent slopes of the mountains.

About 1000 tons of high-grade ore was obtained from one

Manganese Indijstrt Of Department Of Panama. 221

boulder at this point. The original source from which the ore was derived is not known. It is, of course, possible that the boulders represent small deposits of ore exposed by the decom- position and erosion of the surrounding rock.

The rocks associated with the ore are the same as at the Sole- dad mine ; and it seems most probable from the history of other deposits in the region, and the close resemblance in the geologi- cal structure and character of the ore, that the boulders are float from some large deposit upon the mountain as yet undiscov- ered ; or possibly the parent deposit may have been entirely eroded, leaving only the boulders to bear evidence to its exist- ence. The heavy clay mantle which covers the country makes prospecting very difficult and expensive.

The ore at this point is of high grade and closely resembles the Soledad ore, being very hard and steel-gray to black in color, with a conchoidal fracture.

A portable railroad of 0.5 meter gauge, about half a mile in length, connects the mine with the railroad. 'About 2000 tons has been mined at this point.

Culebra Mine.

All the mines previously described are adjacent to the rail- road of the Caribbean Manganese Company. The Culebra is situated upon a small island, about 14 m. east of Sombre De Dios, and half a mile from the mainland, opposite the village of Culebra. The island rises abruptly from about five fathoms of water, and its highest point is about 40 ft. above sea-level. It is about 200 ft. long and 150 ft. wide, the direction of the longer axis being NNE. and SSW.

Apart from the ore-body, the island is composed of the meta- morphosed sedimentary rock previously described as jasper in the Soledad mine. The strata are tilted at an angle of about 80 deg., which corresponds with the dip of the ore-formation at the Soledad mine, and the strike is approximately NNE. and SSW., corresponding to the longer axis of the island, and only varying about 20 deg. from the strike of the ore-formation in the mines to the west.

The manganese-bearing strata are said to be about 80 ft. thick ; and the ore occurs in lenticular or irregular bodies along the bedding-planes. One body of large size has been worked

222 Manganese Industry Op Department Of Panama.

in an open pit, 60 by 45 ft. in area, which was carried 15 ft. below sea-level ; the ore extending into the sea, and a rim of ore being left in place as a sea-wall. During the prevalence of the NE. trade-winds, great difficulty was experienced in work- ing, on account of the heavy seas breaking over the sea-wall and flooding the pit. A shaft is now being sunk from the highest point of the island, and has been carried to a depth of 47 ft. below sea-level. The open workings have been aban- doned.

Ore has been found by borings under the sea upon the direc- tion of the strike about 150 ft. from the island, and is also found upon the mainland about 2 miles SSW. from the island, in the direction of the strike.

The ore is usually hard, although bodies of soft ore are occa- sionally found. The greater part of the ore is a hard black or steel-gray ore closely resembling that at the Soledad mine. It is chiefly psilomelane and pyrolusite, and of high grade.

Both the ore-deposits at this point and the associated rocks are similar to those occurring in the mines to the west, the dip and strike of the formation closely corresponding.

It is therefore probable that they were formed in a similar manner and represent a parallel formation.

About 4000 tons of high-grade ore has been produced here.

The ore is loaded directly into steamers from a wharf built out for a short distance from the island.

The writer is indebted to Mr. M. Filippi, of Brandon, Arias and Filippi, for information concerning the La Guaca and Cu- lebra mines.

The Meamar Mine.

The Meamar mine is about 7 m. E. of Nombre De Dios, and about half a mile from the village of Meamar, or about half- way between the first series of mines described and the Culebra mine.

A small amount of work has been done here by a French company, but no ore has been shipped.

The ore is found, as at other points along the coast, in boulders in a stiff clay of varying color. Boulders of jasper are found with the ore ; and the formation seems to be similar to that of the other deposits described above. A small strati- fied deposit has also been found, dipping at a high angle.

Manganese Industry Of Department Of Panama. 223

The ore appears to be of slightly lower grade than at any of the properties before mentioned.

About' 300 tons has been mined and stored, awaiting some method of transportation to the coast.

Origin and Occurrence of the Ore-Bodies.

As already observed, the rocks associated with the ore- formation are all of sedimentary origin, and the ore-deposits are also undoubtedly a sedimentary formation. As Fig. 2 shows, the four mines of the Caribbean Manganese Company, the Viento Frio, Carano, Concepcion, and Soledad, lie ap- proximately in a straight line, running about S. 3° E. This is also the direction of the strike of the exposed strata at the three mines nearest the sea; and the Soledad mine lies upon the same line, although the strike changes at that point, follow- ing the axis of the foothill range. It is therefore probable that, as the rocks associated with the ore are the same, these four mines are upon the same ore-bearing strata, which consist of decomposed sedimentary rocks, probably shales, though now so decomposed that their original character cannot be decided with certainty. Upon the surface over this area only the clay resulting from the rock decomposition is visible, except where the rock has been preserved by metamorphic action, but at slight depths the original bedding-planes can usually be seen. The maximum thickness of the ore-bearing formation from east to west is about 600 ft., and the strata are sharply upheaved, approaching the vertical. In the lowest workings of the Sole- dad mine, about 230 ft. below the surface, the ore still extends downward.

It is probable that the other mines of the region are upon parallel formations. The strike of the Culebra ore-formation, varying only about 20 deg. from that strike of the formations further west, makes this seem plausible.

The original source of the manganese was probably in the older rocks of the region. Upon the decomposition of these rocks by atmospheric influences, the manganese existing in them in the form of silicate was taken into solution by surface- waters and redeposited as a constituent of the resulting sedi- mentary rocks, or, where conditions were exceptionally favor- able, as bodies of manganese-ore in the form of oxide or car-

224 Manganese Industry Of Department Of Panama.

bonate. The Panama deposits were probably laid down as oxides. No carbonate has been found in the regidn, even in the deepest workings. It is, of course, possible that 6re origi- nally deposited as a carbonate was afterwards converted to an oxide ; in fact, this would probably occur in any portion of the deposit exposed to atmospheric influences. In speaking of the deposition of ore, R. A. F. Penrose says

" When waters containing manga niferous solutions are in rapid motion, as at the mouths of springs, or in rivers and creeks, they are freely exposed to oxidation, and, consequently, the part of the manganese that is precipitated is usually in the oxide form. The part that is not precipitated, however, is carried on to the body of water to which the streams are tributary, and there precipitated, sometimes as oxide and sometimes as carbonate. When the manganiferous solutions in the form of surface-waters are protected from oxidation by being in the presence of a reducing agent, such as veg table or animal matter, they are often precipitated as carbonate. The bicarbonate or other salts of manganese that are in solution, , however, are so easily oxidized that, unless the protection from oxidation is very complete, the manganese is precipitated as oxide/'

When the ore was deposited as a constituent of sedimentary rocks, subsequently upheaved and decomposed, other ore-de- posits may have been formed or existing ones enriched by chemical changes or additions from mineralizing solutions, or by concentration resulting from the weathering of the upper portion of a rock containing ore, thus concentrating in one re- sultant body the ore originally contained in all the portion de- composed above.

The decomposition of the ore-bearing formation in the Pan- ama region was probably hastened by the high angle at which the strata are upturned, allowing free access to surface-waters.

The result of this natural concentration on small ore-deposits, or on rocks containing ore, has often enabled the miner to work profitably the upper portion of a manganese-deposit, while his hopes were suddenly shattered when, at a small depth, the de- posit converged to a narrow stratum of ore, or a mass of lean ore-bearing rock.

The manganese-deposits of the Panama region are probably of Tertiary origin, as will be shown later ; and it is most prob- able that the deposition of ore took place in lagoons along the coast line.

Annual Meport of the Qedhgical Survey of Arkansas for 1890, vol. i., pp. 552, 553.

Makqanbsb Industry Of Dbpartment Of Panama. 225

The geological age of the deposits and the origin of the ore have been discussed by Mr. E. J. Chibas in the paper previ- ously referred to. The conclusions arrived at by him are sub- stantially similar to those of the present paper, except on some points of ore-formation and occurrence depending on the ex- istence of the large deposits in place and the float derived from them. The existence of the deposits in place, in the Soledad mine at least, was unknown when the paper of Mr. Chibas was written.

Probably the most favorable condition that could exist for the formation of a manganese-deposit upon a large scale, where the surface-waters hold manganese in solution, would be the condition that exists to-day along the coast of the manganese- region, where many of the rivers flow into lagoons, and the waters cover a large area of shallow depth. In most of these lagoons no outlet exists to the sea. Some of the water finds its way through to the ocean by filtration, and part is evapo- rated. Under these conditions the solution is concentrated by evaporation ; and, as the water remains in the lagoon for a long period, the oxidation and precipitation of substances held in solution is rendered possible to a greater extent than under most other conditions aflforded by Nature. In addition to the metalliferous solution, the water would hold in suspension the finely-powdered insoluble portions of the disintegrated rock. If conditions were favorable for the deposition of this sus- pended matter at the same time with the chemical precipitation of the ore, the resulting formation would vary from a sedi- mentary rock containing ore to an impure ore. When, how- ever, the conditions favored chemical precipitation only, the result would be a deposit of comparatively pure ore.

In the case under consideration, it is probable that, before the streams reached the lagoons, the greater part of the in- soluble matter originally held in suspension had been deposited, and the conditions were thus more favorable for the formation of a body of pure ore than in the upper portion of the river, nearer to the disintegrated rock. It is probable, except in the case, mentioned elsewhere, of metamorphism accompanied by a high temperature (under which condition the ore would have taken up silica from the surrounding rock, and, if not con- verted into a manganese silicate, would yet have become so VOL. xxxni.— 15

226 Manganbse Industrt Of Dbpartmbnt Of Panama.

siliceous as to be valueless as ore), that the secondary changes in the ore-deposits, after upheaval, were usually in the direc- tion of concentration and enrichment.

The deposition of the ore as an oxide in both rivers and lagoons can be plainly seen in the region at the present day. Pebbles coated with manganese oxide can be found in rivers near the ore-formation. In some places the bed-rock of a stream is covered with a stratum of oxide an inch or more in thickness. In prospecting, it is sometimes necessary to break the loose rocks in the beds of the streams with a hammer, as all have the black coating of oxide, and it is impossible to tell by inspection the manganese-pebbles from the rock-pebbles. Again, a conglomerate made by the cementing of the river- pebbles with manganese oxide is sometimes found in a stream- bed.

In the lagoons along the coast nodules of manganese are often found, in some places very abundantly ; and a deposition of oxide upon a conglomerate occurring near the sea has been noticed.

The deposition of ore in this region is undoubtedly going on at the present day, precisely as in the past, though probably more slowly, because of the smaller amount of manganese in the present sedimentary rocks, and the consequent more dilute character of the metalliferous solutions.

Analyses of Rocks Associated with the Orb-Deposits.

Complete analyses of the rocks associated with the Soledad ore-bodies were made by Dr. C. H. Warren, of Tale University. The rocks are designated by the names under which their occurrence has been previously described at the Soledad mine, viz., shale, jasper and clay.

The results of the analyses were as follows :

Shale.

Jasper.

Claj.

Percent.

Per Cent.

Percent.

Silica (SiO,)

. 74.56

Titanium dioxide (TiO,), .

. 0.48

Trace

Alumina (A1,0s)i

. 9.09

Iron sesquioxide (FejO,), .

Iron protoxide (FeO),

Manganese seequioxide (MnAl

". 1.39

Manganese protoxide (MnO),

Lime(CaO), . . . .

. 0.13

Manganesb Industry Of Dbpartmbnt Of Panama. 227

Baryta (BaO), . Magnesia (MgO), Potash (K,0), . Soda (Na,0), . Water (H,0) at 115 Water (H,0) above 115 Phosphoric acid (PjOj),

Shale. Jasper. Clay.

Per Cent. Per Cent. Per Cent.

0.67 4.68

0.85 0.10 3.18

0.34 0.19 1.76

1.96 3.73

3.20 0.21 4.90

100.12 100.48 100.66

The discussion of the analyses which follows involves the repetition of some facts and theories stated in the preceding pages, which the analytical work appears to confirm.

The rocks are, unfortunately, so decomposed as to afford little clue to their original character. From the descriptions previ- ously given, it is evident that all are of sedimentary origin. Dr. Warren remarks, of the shale, that it is a greatly decom- posed siliceous sedimentary rock, with some of the alumina probably in combination with alkalies and SiO, as some feld- spathoid mineral, and the rest combined as a hydrous alumi- num silicate. The analysis of the jasper gives no clue as to the original rock. It is strongly impregnated with iron oxide, and to a smaller extent with manganese oxide, and highly sili- cified. The clay, he says, as far as the analysis shows, might be the remains of either a basic, igneous, or a sedimentary rock. Some of the SiOj is probably in combination with the alkalies, and part of the AlO,, as a feldspathoid mineral ; some with Al,Oa and H,0 as a hydrous aluminum silicate ; and some, possibly, with magnesium and water as a hydrated magnesium silicate. The clay represents in all probability a rock, now completely decomposed, originally laid down with the manga- nese. This is shown by its position in the ore-bodies, and is confirmed by the chemical analysis, which shows a concentra- tion of metallic contents as the ore-body is approached. The close relation of the clay to the ore is shown by the high per- centage of iron and manganese oxides contained in it, and by the presence of baryta, usually an accessory constituent of psilomelane, of which the ore-body is partly composed. Potr ash is also usually found in psilomelane ; and the greater per- centage of this in the clay than in the other rocks is noticeable. Some authorities classify psilomelane as baryta-psilomelane or

228 Manganese Industry Of Department Of Panama.

potash-psilomelane, according to the predominance of the accompanying mineral. Dana says {System of Mineralogy) that a part of the manganese in psilomelane is replaced by barium or potassium.

It is impossible to determine from the analyses the original character of any of the three rocks ; but it is probable that the shale and jasper were originally identical sedimentary rocks, and that the jasper is the metamorphosed shale. This is indi- cated by the physical appearance of the rocks and the blend- ing of the jasper into the unaltered shale, both vertically and horizontally.

There was no general regional metamorphism ; but during the uplifting of the country volcanic forces were active, and local metamorphism of the sedimentary rocks occurred from the effects of the eruption of igneous rocks, as well as from the general dynamic eff*ects of the elevation of the country.

In general, the metamorphism of the rock probably caused no great change in the character of the ore. A low tempera- ture usually accompanied the process, as is shown by the fact that the ore remained, even in contact with the metamorphosed shale, as an oxide low in silica. Under this condition, the ten- dency of the metamorphic action was to consolidate the ore, and convert it from the stratified to the massive form. On the contrary, where a high temperature accompanied local meta- morphic action, the manganese oxide was changed to a silicate, or at least took up a large amount of silica from the rock. A good example of this is shown in one portion of a deposit in the region where it has been subjected to a high temperature from a volcanic eruption. The ore is covered by volcanic ash and fragments of lava, and has been converted into a light, scoriaceous mass, strongly impregnated with silica, while an area of surrounding shale has been converted to jasper.

A somewhat similar instance of the metamorphism of shales to jaspers in the coast ranges of California is described by G. F. Becker.*

The high silica contents of the jasper shown by the analy- sis are noticeable. This may possibly be due, in part (aside from the original metamorphic action), to the action of miner- alizing solutions from surface-waters flowing along the steeply-

Geology of the Quicksilver Deposits of the Pacific Slope U. S. Geol. Survej, 1888.

Manganese Industry Of Department Of Panama. 229

inclined strata of the decomposing shale, and causing, after the upheaval, a secondary enrichment of the manganese deposit. To these ore-bearing solutions, the mineral contents of which were derived from the decomposition of the sedimentary rock, the jasper, by virtue of its position on the north of the deposit, and its more compact structure after metamorphism, acted as a dam, against which the deposition of ore from the solutions took place upon the existing deposit, while the rock under- went more thorough silicification. The jasper and shale can thus be considered to have been originally identical.

The clay, on the other hand, as already observed, was prob- ably deposited simultaneously with the ore at periods or in places where the conditions favored the deposition of the in- soluble suspended particles of the disintegrated original rock, instead of the chemical precipitation of the ore-bearing solu- tions derived from the same source.

The original of the clay would therefore have been a sedi- mentary rock, probably somewhat similar in character to the shale, but with a greater amount of manganese contents, due to its closer relationship to the ore. When deposited, the clay represented the insoluble constituents of the primary rock ot the region, the original source of the manganese. From the breaking down of these rocks, the manganese deposits and re- lated sedimentary rocks were formed.

Age of the Manganese Deposits.

It is believed by geologists that the Isthmus was submerged until after the close of the Paleozoic era. Th6 Western Cor- dillera of the Andes, which comprises the ranges on the Isth- mus, probably first appeared above the sea in the Jurassic period. Of the three branches of the Andes, the Eastern, Cen- tral and Western Cordilleras, the Central is probably the oldest. Its upheaval has been placed by J. C. F. Randolph* at the end of the Triassic or the beginning of the Jurassic era, and he considers that the Western Cordillera was ele- vated at some period during Jurassic or Triassic time. A slow but gradual upheaval continued ; but, as late as the Cretaceous, the waters of the Atlantic and Pacific probably blended in a shallow sea studded with islands.

♦ Trans,, xriii., 209.

230 Manoanebe Industry Of Department Of Panama.

Prof. J. D. Dana says, in hie Manual of Geology that a shal- low water-connection across the Isthmus probably existed as late as the Cretaceous, as has been inferred from the parallel series of representative species now existing on the two sides.

At the close of the Cretaceous, Hermann Karsten* considers that the Western Cordillera had only the summits of its peaks above the sea, as a chain of islands. In his geological map of Colombia, Karsten shows the Isthmus in the immediate Panama region, as in the area covered by the manganese-deposits, as entirely of Tertiary and Quaternary formation, with numerous small isolated areas of igneous rock, the result of eruptions through the stratified deposits. He describes the region as dotted with numerous cones of dolerite, trachyte and basalt, associated with tuffs and a volcanic conglomerate — the igneous rocks occurring in a Tertiary shell-breccia, and in sandstone of the same geological period.

The elevation of the country extended throughout the entire Tertiary period; and it is believed by some geologists that slight additions to the land-area were made during the Quater- nary.

The manganese-deposits, which are considered to have been formed in lagoons along the coast, were, if the theory is cor- rect, laid down along the coast-line of the Tertiary sea, and subsequently upheaved in the general elevation of the country. In fact, whether deposited as suggested or not, it is difficult to place them elsewhere than in the Tertiary period.

Many of the present workable deposits were probably en- riched during the present geological age by chemical changes and processes of secondary concentration previously discussed.

No fossils have been found in any of the workings, and it is therefore not possible to confirm any theory of the period of their formation by paleontological evidence.

Climate and Rainfall.

The heat-equator or line of maximum temperature intersects the Isthmus of Panama at about 8 deg. N. latitude. The aver- age daily temperatures are high, and there is but little variation in temperature throughout the year.

QMogie de Pcmcienne CMomJbie BoUvarimnef etc.

Manganese Industry Of Department Of Panama. 281

Becords kept for two years at the Soledad mine, aboat 700 ft. above Bea-level, show the average of the maximum daily temperatures for. that period to be about 87 deg., and the min- imum daily average to be between 72 and 73 deg. The tem- perature at the coast probably ranges from 2 to 8 deg. higher than this. The highest monthly average of maximum daily temperatures recorded at the mine was 90 deg.; the lowest monthly average of minimum daily temperatures was between 71 and 72 deg. The heat is rendered more oppressive by the excessive humidity. For the period under consideration no hygrometer-reading was taken showing less than 88 per cent, of humidity. The average daily humidity recorded was 89 per cent.

The rainfall is very high, probably averaging at the mines about 175 in. annually. Records fortwo years at the Soledad mine gave an annual fall of 176.08 in. Nearly all of the rain falls in the nine months of the wet season. The dry season usually extends from January 15 to April 15, and in this period very little rain falls.

The greatest monthly fall recorded was about 85 in. The greatest rainfall recorded in 24 hours was 15.49 in. During this deluge 8.84 in. fell in the first 5 hours, and 14.85 in. the first 11.5 hours.

The average of the maximum daily fall each month for the two years is 8.06 in. The greatest intensity of fall recorded is 1 in. in 18 min., or at the rate of 8.88 in. per hour; and an actual rainfall of 8 in. in 1 hour has been noted.

The rainfall at the coast is somewhat less than at the mines, the greater precipitation occurring on the first range of foot- hills. This heavy rainfall has had a great efiect, during the present geological period, in moulding the topography of the country.

The Panama climate has a bad reputation abroad, which is not wholly deserved. Yellow fever is unknown in the country districts. A malarial fever is common along the coast, but it rarely assumes a dangerous form. A person living in a settled district, where good food and shelter are obtainable, should have no difliculty, with an occasional trip to a cooler climate, in pre- serving his health. An engineer's work usually calls him to the wilder parts of the country, where he has to endure many

282 Manganese Industry Of Department Of Panama.

hardships ; and even in the settled portions, his position usually calls for greater exposure to the climate and its enervating ef- fects than falls to the lot of those engaged in ptiercantile life in the towns. Even under these unfavorable conditions, men of good constitution, who observe the proper laws of living, find no great difficulty in keeping in good physical condition.

Timber-Supply.

The country is covered with a dense forest, but most of the trees are of soft woods, of little durability, and altogether un- suitable for building-purposes or mine-timbers. Mine-, bridge- and wharf-timbers, railroad-ties, etc., are all cut in the country, but only the heavier and harder growths are used. The most desirable woods for general work, aside from piles in salt water exposed to the teredo have been found to be rdspero a hard red-wood of great durability, and coutaro and black giiia- carty varieties of lignum vitcB. These woods all sink in water, and are so hard that a nail cannot be driven into them. All the holes for the spikes in railroad-ties have to be bored with an auger of slightly smaller diameter than the spike. Ko wood in the country fit to use for a railroad-tie, into which a spike can be driven, is known to the writer.

In wharf-work in salt water the hardest and most compact woods are riddled by the teredo more quickly than the softer varieties, unless they possess some essential quality of bitterness, or astringency, that causes the teredo to avoid them. It has been found by experience in this latitude that it is a waste of money to select valuable woods for piles, as they are destroyed by the teredo long before decay attacks them. Palms, and other fibrous, loose-grained woods, survive the longest, but have not sufficient strength for heavy wharf-structures. The partial exemption of the fibrous woods is due, as shown by Mr. Charles H. Snow,* to the dislike of the teiedo to a wood with cracks or a fibrous struc- ture, because of the greater difficulty of keeping intact the calcareous lining-tube of the tunnel it bores. The writer tried many woods, and found two which are partially exempt, so that they can be safely counted on for a life of from 2 to 3 years, namely, the red mangrove {mangle Colorado) and the alcarato. The

♦ Tram. Am, Sac C. R, vol. xl., p. 178, Marine Wood-Bopers."

Manganese Industry Of Department Of Panama. 283

former wood grows in lagoons and low, swampy land along the seacoast and has highly astringent properties. The pounded bark is thrown by the natives into pools and small streams to poison fish. It is difficult to procure this timber in pieces of sufficient size and straightness for heavy piles. The cdcarato piles are intensely bitter, and both woods appear to be shunned by the teredo until long immersion has extracted their astringent and bitter properties. All the other woods tested, except the palms, which are unsuitable for heavy structures, can only be counted on for a life of from six months to a year. The Santa Maria wood, quoted by Mr. Snow from a work of Mr. T. A. Britton as partially exempt, has not been found to be so by the writer. The woods tested in wharf-structures exposed to the teredo embrace all the woods in common use in the country for structural purposes. It would appear that no native woods are sufficiently exempt to be of any great value ; and it is better to import creosoted piles, or, better still, to use iron or steel piles, in a wharf designed as a permanent structure.

It is the general belief of the natives of the country .that timber must be cut in the period after the full moon and before the new moon, or otherwise it will soon decay. This belief is always regarded by strangers in the country as a superstition ; but experience shows it to be based on fact. With the hardest varieties of wood in use, such as black gviacan or nispero little difference is noticed, whether the rule is kept or violated ; but, with the exception of a few of the harder varieties, the woods, if cut during the waxing moon, begin to rot almost im- mediately, and also become infested with a borer that riddles the outer sap-wood. The fact has been noticed by many ob- servers doing work in the country.*

Mr. Woakes advances the theory that there is a greater amount of sap present in the wood during the waxing moon, and its fermentation and decomposition hasten the decay of the wood when cut during this period. Perhaps the most striking illustration of the fact is given in the thatched-roof houses common in the country, where the thatch is composed of a species of palm-leaf. The leaves cut during the first phases of the moon become useless in fifteen days, being literally eaten

See the paper of Ernest R. Woakes, '' Modem Qold-Mining in the Darien," SVofw.., xxix., 249.

284 Manganese Industry Of Department Of Panama.

up by worms, while the same leaves, cut during the last quar- ter of the moon, do good service as roofing for a year. What- ever the cause, the facts are as stated, although the writer does not expect Imybody unaccustomed to the country to believe them. As an actual test is always sufficient to convince the most skeptical, he hopes, for their own sakes, if they are ever called upon to erect in this latitude timber-structures of native wood,, they will make some experiments as to the influence of the time of cutting upon the durability of the wood before pro- ceeding with their work.

Careful inspection of all timber-structures is necessary, to preserve them from destruction by the white wood-ant. If left undisturbed, these ants will soon destroy any structure, taking out almost the entire interior of a stick of timber, and leaving a shell on the outside of apparently good wood. Fortunately, they find lignum vitce and nispero difficult boring; and, until these woods begin to soften through decay, they do not attack them beyond destroying the sap-wood.

Mining Laws and Labor-Supply.

The mining laws of Colombia are just and liberal. It is an easy matter for either a foreigner or a native to take up a mining claim upon Government land, and a complete title can be secured at a small expense.

For the last three years the country has been distracted by a revolution, and business has been greatly interrupted. In normal times the stranger will find that the establishment of any new industry will be cordially welcomed.

In the interior of the country a large part of the population are supported by the mining industry ; but the natives along the coast do not take kindly to underground work, and it is usually necessary to employ laborers from the West Indies.

For any enterprise in the Department of Panama, there is usually an available supply of laborers domiciled along the line of the Panama Canal.

MINING INDUSTRY OF THB C(EUR d'ALBNES, IDAHO. 235

The Mining Industry of the Cceur d'Alenes, Idaho.

BT J. B. riNLAY, COLORADO SPRINGS, COLO. (New York and PhiUdelphia Meeting. February and May. 1902.)

I. General Description.

The Cceur d'Alene silver-lead mining district of northern Idaho is probably best known to the general public as a seat of labor-troubles. So far as the writer is aware, little has been written and little is known about its geology and resources. People interested in lead-smelting are, of course, cognizant of the economic importance of the region, but they have not com- municated much of their knowledge to the public.

Exact figures as to the total output of the district are not obtainable, but the following estimates, covering the entire out- put of the 15 years during which the mines have been operated, are believed to be approximately correct :

Group of Mines. Product.

Wardner Group, including the Bunker Hill and Sul- livan, Empire State-Idaho, Last Chance, Sierra Nevada, Goeur d'Alene Development Co., . $17,600,000

Cafion Creek Group, including the Gem, Fruco Con- solidated, Granite, Standard, Mammoth, Hecla, Tiger-Poorman, Custer and Bell, 35,000,000

Mullan Group, including the Morning, You Like and Gold Hunter, 7,500,000

$00,000,000

This output covers the period of discovery and early strug- gles, and several periods of stagnation caused by strikes and other serious labor-troubles. In 1900 the output of the dis- trict was fully 110,000,000, and this figure would have been considerably increased in 1901 had not a curtailment of produc- tion been forced by the condition of the lead-market. In 1901 the product was about 150,000 tons of concentrates, with a gross value of 18,250,000.

286 MINING INDUSTRY OF TUB GCBUR d'ALBNSS, IDAHO.

The accompanying map (Fig. 1) shows the principal mining claims in this region. The numbers on the map indicate the locations, as follows :

Ve

1. Manila.

52. San Carlos.

102. Emma.

2. Sonny.

53. Likely.

103. Kruger.

3. O. K. Western.

54. Skookum.

104. Cuban Mines.

4. Whippoorwill.

55. Jersey Fraction.

105. Silver.

5. Mabel.

56. McLellan.

106. Johannesburg.

lui

6. 0. K.

57. Lilly May.

107. Forest BeUe.

7. Johnuj.

58. Deadwood.

106. Bunker Hill Mines.

8. Danish.

59. Sought Again.

109. Bunker Hill.

9. Beeres.

60. Coxey.

110. Important.

Ml 1

10. Packard.

61. Debs.

111. Phil. Sheridan.

11. Royal Knight.

62. Carter.

112. Chestnut.

12. Queen.

63. Josie.

113. Ivanhoe FnoUon (?).

8C*

13. Eareka.

64. AlUe.

114. Blue Bird.

IWCti

14. Crown Point.

66. Jack Ass.

115. Geyser (t).

15. Heary.

66. Sold Again.

116. Susie.

16. SiWer King.

67. Kirby.

117. Maple.

17. Senator Stewart.

68. Shoshone.

118. Rookery.

18. Quaker.

69. Summit.

119. Homestake.

19. Silver Ossket.

70. Miles.

120. Butternut.

20. Oalifomia.

71. Teddy.

121. African Reef.

21. Idaho.

72. Republican.

122. Mary.

22. Legal Tender.

73. Tyler.

123. Benlah.

23. Harrison.

74. King.

124. Zululand.

24. Princess.

75. Pitt.

125. Matabela-Und.

25. Sagar.

76. Cheyenne.

126. Stopping.

26. Fifty-Three.

77. Wasp.

127. Buckeye.

27. Florence.

78. Wheel Barrow.

128. Reed.

Of

28. No. Five.

79. New Era.

129. Sullivan.

29. No. One.

80. Bee.

130. Small Hopes.

30. No. Two.

81. Hornet.

131. Lackawanna.

t.

31. No. Three.

82. Hawk.

132. Alia.

32. No. Four.

83. Caledonia.

133. Mashonaland.

j

33. Ontario.

84. O'Connor.

134. Mabundaland.

34. Ontario Fraction.

85. Omaha.

135. No Name.

35. Carbonate.

86. Scorpion.

136. Miners Delight.

36. Sierra Nevada.

87. Oregon.

137. East*

37. Tip Top.

88. Combination.

138. Sullivan Fraction.

38. Apex.

89. Holman.

139. RoUing Stone.

39. Rambler.

90. Butler.

140. Daisy.

40. OakUnd.

91. Kaintuck.

141. Fair View.

41. Excelsior.

92. Dakota.

142. Schofleld.

42. Cariboo.

93. Capetown.

143. OUieMcMiUen.

43. Good Luck.

94. Emma A Last Chance

144. Bonanza.

44. Butte.

Mines.

145. Iron Hill.

45. Hard-Cash.

95. Puriten.

146. La CrosBe.

46. Hamilton Fraction.

96. Idaho.

147. Summit

47. Hamilton.

97. Utah.

148. Justice.

48. Nevada.

96. Last Chance.

149. Jessie.

49. Link.

99. Sampson.

150. Comstock.

50. Arisona.

100. Helen Mar.

151. Ophir.

51. Viola.

101. Stem Winder.

152. Dandy.

FINLAY.— Fig. 1.

ver:

Ho

', '

rtJ

riii< ;/! e-f' qiflenwoT

/ J

K

r:.non

1

A

f.

MINING INDUSTRY OF THE CCEUR D'aLBNBS, IDAHO. 237

153. Jolia.

154. Wall Walla.

155. Midday.

156. No. 1.

157. Lncky Chance. 156. Bonnie Jean. 150. Toagh Nut 100. Inka.

161. Milo.

162. Fannie May.

163. Protection.

164. Alhambra.

165. Dawn.

166. MoKinley.

167. Monte Gristo.

168. Crescent

169. Brile Mines.

170. Soathem Cross.

171. Omega.

172. Polaris.

173. 8tep-and-a-Half.

174. Chester.

175. Protection.

176. Hanna.

177. McKinley.

178. Bartlett.

179. Emma Nevada.

180. Ccenr d'Alene Nellie.

181. Argentine.

182. Argentine Fraction.

183. Keystone.

184. Lee.

185. Brewery Mines.

186. Brewery.

187. Electric Light Co.'8

Grounds.

188. Big Medicine. 180. Union Mines.

190. Vermont.

191. Ore-Or-No-Qo Mines.

192. Bine Tanlk.

193. Brother.

194. Sister.

195. Oro Fine.

196. Silver Wave.

197. Sanshine Mines.

198. Black Cload Mines.

199. Sanshine.

200. Iowa. 20L Monarch.

202. Black aond.

203. Psciflc.

204. Ninety-Nine.

205. Contact

206. Mountain Chief. gO?. Shamrock.

206. Black Prince. 200. Divide.

210. Marietta.

211. Hornet.

212. Idaho.

213. Panhandle.

214. Ohio.

215. Bonanza.

216. Nngget Placer.

217. Johnny Placer.

218. Figard.

219. Banner.

220. Lucky Boy.

221. Iron Mask.

222. Idaho Mint

223. Lucky Boy Fraction.

224. Yellow Jacket

225. Free Coinage.

226. Speckled Trout

227. Anna.

228. Topeka.

229. Pierce.

230. Mell.

231. Custer Mines.

232. Star.

233. Treasure Vault

234. Mingo Chief.

235. Kola.

236. Belle of the West

237. Tugela.

238. Belle Fraction.

239. Trade Dollar.

240. Granite.

241. Denver.

242. Crystal.

243. Empire State.

244. Manila.

245. Manila Fraction.

246. Old Hickory.

247. Daisy.

248. Patuzent.

249. American Eagle.

250. Eagle Fraction.

251. Bi-Metallic.

252. 16-to-l.

253. Hawaiian.

254. Ambitious.

255. Lucky Jim.

256. Yew.

257. Miller.

258. Aspen.

259. Jenkins.

260. Chilcot

261. Bosa.

262. Bosa Fraction.

263. Mase.

264. Mascot

265. Blarney Stone.

266. Knapp.

267. May Flower.

268. Protection.

269. Dobson Jim.

270. White Quarts.

271. Estelle.

272. Virginia Placer.

273. Idaho.

274. North Star Mines.

275. Grace.

276. Minneapolis.

277. Sunlight Placer.

278. Fidelity.

279. CcBur d'Alene Chief.

280. Morning Light.

281. Emma A.

282. Fanny Peak.

283. Faithful.

284. HopeAil.

285. Security.

286. Dorothy Hill.

287. Cariisle.

288. President

289. Lucy.

290. Merrimac.

291. Monitor.

292. Monitor Fraction.

293. Manhattan Fraction.

294. Mountain Goat

295. Amazon.

296. New York.

297. Staten Island.

298. Ajaz.

299. Father.

300. Diamond Fraction.

301. Chloride Queen.

302. Switch Back.

303. Boy.

304. Boy Fraction.

305. Live Oak.

306. Tough Nut

307. Colwyn.

308. Toscumbia.

309. West

310. Parallel.

311. Sitting Bull.

312. Silver Tip Fraction.

313. Parrot

314. Mule Deer.

315. Silver Tip.

316. Bed Dragon.

317. Son Set

318. Big Bug.

319. Ula.

288 MINING INDUSTRY OF THE CCEUR d'aLBNBS, IDAHO.

320. Try Me.

321. NiluB.

322. Leonard.

323. Polly.

324. Tamarack.

325. Tamerlane.

326. Chesapeake.

327. Carbon.

328. Caster.

329. Paoiflc.

330. Timber Line.

331. Boee.

332. Diamond.

333. Green Hill.

334. Cleveland.

335. Green Hill Fraction.

336. Grey Eagle.

337. Head Light.

338. Mammoth.

339. Tariff.

340. Mammoth Fraction.

341. Little Chap.

342. Snow Line.

343. Saturday.

344. Walter McKay.

345. Bonaparte.

346. Sancho.

347. Crown Point.

348. Fairview Fraction.

349. Sherman.

350. Union Fraction.

351. Union.

352. Bengal Tiger Fraction.

353. Hidden Treasure.

354. Burke Tiger.

355. Stanley.

356. Silver Chief No. 2.

357. Wide West.

358. Shoo Fly.

359. Tiger.

360. Sheridan.

361. Bullion.

362. Galena.

363. Bullion Mines.

364. Liebes Fraction.

365. Reeves Mines.

366. Diamond Hitch.

367. Seattle.

368. Wellington.

369. Banner Fraction.

370. Banner.

371. Silver Queen.

372. Anchor.

373. Toungstown.

374. Bonanza.

375. Sandwich.

376. Sullivan.

377. Standard. 377a. Combination.

378. Gray Copper Fraction.

379. Gray Copper.

380. Crown Point.

381. Tom Reed.

382. Selkirk.

383. Akron.

384. Broad Gauge.

385. Narrow Gauge.

386. Chief.

387. Josie.

388. Qem of the Mountains.

389. San Francisco.

390. Esler.

391. Yankee Doodle.

392. Esler Fraction.

393. Apex.

394. Cape Horn.

395. Idaho.

396. Black Bear.

397. Badger.

398. Gem Fraction.

399. So Mote It Be.

400. Moon Light.

401. Grover Cleveland.

402. Black Bear Fraction.

403. Protection.

404. Queen of the Hills.

405. Grubstake.

406. Grubstake Fraction.

407. Bell.

408. Contention.

409. Bell Fraction.

410. aimax.

411. Iron Silver.

412. Josephine.

413. Tuff Nut No. 2.

414. Tuff Nut.

415. Exchequer.

416. Mountain Fraction. 417.. Muulton.

418. MounUin View No. 2.

419. MounUin View.

420. Senator.

421. Senator Fraction.

422. Parrott Fraction.

423. Buffalo Fraction.

424. Denver.

425. Ore-or-No-Go.

426. Hecla.

427. Sunday.

428. Poor Man.

429. Burke.

430. Ella.

431. Fuller.

432. Protection.

433. Green Mountain.

434. Got-'em-Now.

435. Mat.

436. Parrott.

437. Sonora Mines.

438. Modock.

439. Sonora Fraction.

440. Sonora.

441. Alameda.

442. First Chance.

443. Great Hope.

444. First Chance Fraction.

445. May Flower.

446. Clark.

447. O'Neil. 447a. Columbia.

448. Mond.

449. Russell. 460. Ironside.

451. Consolidated Ext.

452. Katie May.

453. Orphan Boy.

454. Orphan Girl.

455. Muscatine Fraction.

456. Burlington.

457. CroBsus.

458. Muscatine.

459. Star.

460. Leadville Fraction.

461. Leadville.

462. Ore-or-No-Go Fraction.

463. Dipper.

464. San Jos4.

465. Little Strike.

466. Iron Crown.

467. Iron Crown Fraction.

468. Lauren J.

469. Hickory.

470. Grouse.

471. Noon Day.

472. Morning.

473. Silver King.

474. Evening.

475. Midnight.

476. You Like.

477. Bummer.

478. Silver Queen.

479. Park.

480. Independence.

481. Fanny Gremm.

482. Still Water.

483. Lucretia.

484. Key.

485. Contact.

Mining Industry Of The Ccbur D'Albnbs, Idaho.

486. Qettysbarg.

487. Trae Blae.

488. Buckeye.

489. WarDftuce.

490. Victor.

491. Lost Wonder.

492. Victor Fraction.

493. Jersey Minor.

494. Pay Master.

495. Ada.

496. Tolande.

497. Ida.

496. Clear Grit.

499. America.

500. Coban Bepoblic.

501. Mary Norem.

502. Commander.

503. Gold Hnnter.

504. Away Up.

505. Joe Dandy.

506. Enterprise.

507. Bullion. 506. Pine Tree.

509. Defiance.

510. Mullan.

511. True Blue.

512. West Mullan.

513. Midnight No. 2. 514.' Hennessey Mines.

515. Ryan Mines.

516. Thos. Brenan Mines.

517. P. M. Kavana. 51& Central.

519. Cape Nome.

520. Crown Mines.

521. Morning Miues.

522. Evening Mines.

523. Hattie.

524. Klondike.

525. 8now Flake.

526. Club.

527. Gold Queen.

528. Hammerfest.

529. May Flower.

530. Cape Nome.

531. Surprise.

532. Sunshine.

533. Sunshine Fraction.

534. Gold Drop.

The central point of the district is the town of Wallace (see Pig. 10), which is reached from the east by a branch of the Northern Pacific railroad from Missoula, Mont, and from the west by a branch of the Oregon Railroad and Navigation Co.'s line from Tekoa, Wash. From Wallace to Missoula is 185, to Spokane, 129 miles.

The main feature of the topography is the low range locally termed the Cceur d'Alene mountains, which are merely the northern extremity of the Bitter Root range. The highest summits in the neighborhood of the mines scarcely exceed 6000 ft. in altitude. The mountains are rather the remnants of a deeply-eroded broad plateau than a well-defined range. The mines are all within the drainage of the South Fork of the Cceur d'Alene river. The veins have been found outcropping, at altitudes varying from 2400 ft. at the extreme west to 6000 ft. at the eastern and northern extremities, along the various streams which empty into this river. The country was once covered with a dense forest of fir, pine, cedar and tamarack. Near the mines a good deal of the original forest has been de- stroyed by fire or axe ; but everywhere a new growth keeps the hills green.

The climate is healthful and pleasant. The residents live at an average altitude of about 3000 ft. There are no great ex- tremes of heat or cold. The mercury rarely goes below zero F. in the winter or above 80® F. in the summer. In the val- leys, the snow generally lasts from November to March ; on the summits, from October to June. Violent wind-storms are un-

240 MINING INDUSTRY OF THE CCBUR d'aLENBS, IDAHO.

known. Occasional snowslides on the steep sides of the val- leys have caused some interruption of travel and some loss of life. (See Pig. 20.)

The geology of the-Coeur d'Alenes has never been thor- oughly studied, and practically no details of it can be given.. A vast formation of slates, greywackes and quartzites, thrown into east and west folds, covers the entire region. These rocks are all fine-grained, no conglomerates or even moderately coarse sandstones being seen anywhere. True vitreous quartz- ites are rare. The rocks in which the lead-bearing veins occur are usually light-colored, and could be best described as fine- grained greywacke, or something between slate and quartzite There is only a mild regional metamorphism. As a rule, very little formation of new minerals has taken place in the rocks. They are generally nicely banded, though the stratification is often obscured by dynamic action. Rarely, however, is there a well-developed cleavage. The movements in the rocks have only produced a strong jointing in a direction usually par- allel to the neighboring fissure-veins. This jointing is so pronounced in places as to give a schistose character to the rocks.

Igneous intrusions are rare. Only two kinds have been ob- served. The most important is a syenite or quartzless granite, which makes an enormous boss or dike on tjie ridge between Canon and Nine Mile creeks. This mass has produced a well- marked contact-metamorphism in the slates and greywackes which surround it, and has exercised an important influence on the vein-formation of its neighborhood. The important mines on Canon creek are all within a mile of it ; and silver-lead veins of more or less value occur at intervals along its whole per- iphery, and even within its borders. It is well known to the miners of the country as " the granite."

At a number of places there are basic dikes, usually narrow, producing little or no metamorphism in the sedimentary rocks, dark-green in color, heavy and unaltered. Most of them are probably basalt. In some cases they cut through the lead- bearing fissures, with no effect whatever on the values or the mineralization of the veins. But in one important instance the Hecla vein follows a narrow dike of basalt for its entire length. The mineralization has taken place along the walls of the dike,

MINING INDUSTRY OF THE C(EUR d'ALENBS, IDAHO. 241

and in many places the basalt seems to have been, to some ex- tent, actually replaced by galena.

n. Veins and Ore-Dbposits.

All the ores of the region come from typical fissure-veins, in which argentiferous galena is associated with large quantities of siderite. The fissures occupy fault-planes, on which the amount of movement is indeterminate, but probably, in some cases, considerable. The fissure is usually well marked by a streak of gouge, between walls which are slickensided and often beautifully polished. As a general rule, only one prin- cipal plane of fissuring can be found in each vein. This is very apt to occur near the middle of the vein, but often forms one wall of the lode. Two defined walls, marked by planes of movement, are extremely uncommon.

The principal minerals of the lead-bearing lodes are quartz, siderite, galena, zinc-blende and pyrite. Near the surface, oxi- dation has produced lead carbonates, iron oxides, manganese oxides and native silver.

The minerals in some veins are scattered somewhat indis- criminately through the mineralized zone ; but they are more apt to be arranged in streaks or zones parallel to the master- fissure. It is noticeable that, along the actual fissure-plane, the galena and other minerals are nearly always fine-grained, while at some distance from it they are apt to be much coarser. The probable reason is, that the movements along the fissure continued during the process of mineralization, breaking up the minerals after their deposition, and allowing the deposition of fresh material in the interstices.

In some veins the minerals are found to be well segregated in individual streaks, the argentiferous galena, for instance, forming seams containing from 60 to 80 per cent, of lead. In other veins, or even in other parts of the same vein, the various minerals are intimately mixed in the same ore-streak, greatly diminishing its value. In different mines, and even in the same mine, the proportion of silver in the galena varies greatly: say, from 0.25 to 2 oz. of silver to 1 per cent, of lead. Ordinarily this variation follows some fixed law in each de- posit ; but the law is seldom the same in two deposits. In some mines the silver-values increase or diminish longitudinally voT xxxni. — 16

242 Mining Industry Of The Ccbur D'Albnbs, Idaho.

along the vein ; in others, they diminish proportionately with depth.

The ore-bodies occur in every conceivable position, from horizontal to vertical. Some of them are very large, containing millions of tons of concentrating-ore. Three of the most valu- able deposits in the district do not reach the surface at all, their apexes lying several hundred feet below it. Two of these are, and the third is not, quite below the limits of oxidation. It does not appear that leaching by surface-waters has in many cases destroyed the lead-values, but there are instances where this has happened. The workable deposits, as mined, carry from 5 to 25 per cent of lead. The average values for the district are perhaps 10 per cent of lead and 7 oz. per ton of silver.

The following are descriptions of some of the typical lodes.

The Bunker Bill Lode. (See Figs. 2, 3 and 14.)

This remarkable fissure diflfers notably from the other veins of the Coeur d'Alenes. It seems to be the sole source of the ore in the Wardner district. For 6000 ft. from the eastern end of the workings of the Bunker Hill and Sullivan to the Viola claim of the Empire State-Idaho, the workings are continuous. From the Viola northwestward to the Crown Point the continuity of the fissure is not so clearly established ; but all the ore that has been found follows the same extended line, and the workings on the Silver King and Crown Point display a fissure with the same dip, strike and general charac- teristics as in the Bunker Hill.

In the greater part of the course of the vein the fine-grained quartzites dip S. 60° to 70°, and strike K 70° W.; but in places anticlines and synclines are cut through. It is quite probable that these folds are subsidiary to the grand fold of the neighborhood, but no detailed study has thus far determined this to be a fact.

The fissure strikes K 30° W. and dips 40° SW., thus cut- ting the stratification at a considerable angle, both on the dip and strike, — a fact which is considered to have had a great in- fluence on the deposition and arrangement of the ores.

It is a remarkable fact that all the mineralization has taken place on the hanging-wall side of the fissure, which therefore

HDTIMa INDt'STRY OF THE 0<EUR d'aLBNKS, IDAHO. 243

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forms the foot-wall of the lode. A characteristic white " gouge " of thoroughly crushed and altered rock lies upon the unchanged country quartzite of the foot-wall. Lying upon this white gouge is a strongly mineralized zone, which begins with a streak of bluish or black gouge containing galena, always very fine-grained. The lamination of the rocks paral- lel to the fissure-plane is strongly marked for only a moderate distance (from 5 to 50 ft.) from it; but within this zone of parallel lamination the minerals, valuable or otherwise, are in- variably fine-grained. The lamination in this foot-wall zone has reduced the rock to the condition of gouge-material only for a foot or two next the foot-wall.

Passing outward from the fissure, find the mineralization

Fig. 3.

Sketch, Showing in Vertical Section the Relation of the Sierra Nevada and Bunker EQll Lode.

extending far into the hanging-wall, which has undergone much fracturing. For from 100 to 300 ft. from the fissure, the joints and seams in the quartzite are apt to be filled with galena, with subsidiary quartz and iron carbonate. Further from the foot-wall, the quartz, siderite and pyrite predominate, to the final exclusion of the galena. These minerals give the rocks towards the hanging-wall a silicified appearance ; and in the outer zone of mineralization they make the rock much harder than the country-rock of the hanging-wall or the vein itself, nearer the foot-wall, and sometimes the lode forms great bluffs. For this reason, the prominent outcrops represent this portion of it.

The quartz, siderite and pyrite in their turn diminish in amount until at, usually, not more than 400 ft. from the foot-

MINING INDUSTRY OF THE C(EUR d'ALENES, IDAHO. 245

wall, all mineralization has disappeared, and the country quart- zite of the hanging- wall resumes the appearance of the foot-wall quartzite.

The workable ore-bodies in the Bunker Hill lode are simply those portions which contain enough galena to pay for work- ing. Ordinarily, such bodies lie partly in the laminated zone next to the foot-wall or fissure, and partly in the fractured rock in immediate contact with this zone, on the hanging-wall. In almost every case, ore-bodies appearing in some places to be at a considerable distance from the foot-wall have been found, when followed up, to connect with it There are, however, three conspicuous ore-bodies, the " workable " connection of which with the foot-wall has never been established. Two of these (the Curtis-Hatton body in the Bunker Hill, and the hanging-wall stopes in the Last Chance claim) seem to follow

FiQ. 4.

Sketchy Showing the Sierra Nevada Vein in Longitudinal Vertical Section.

channels made in some way by the fracturing of the hanging- wall in a course essentially parallel to the foot-wall, but at some distance from it ; and the third, the Sierra Nevada deposit, is a unique occurrence, which merits a more extended description. As a general fact, however, it may be declared that the main foot-wall fissure was the source of all the mineral deposition along the lode ; that the ore-bearing solutions have enriched portions of the hanging-wall country wherever a favorable channel existed ; and that these channels may have been cross- fractures or local branch-fissures, regions of extensive crevice openings due to jointing, or openings along the bedding-planes of the rocks.

The Sierra Nevada Lode. (See Figs. 3, 4 and 5.)

This is a peculiar and highly specialized example of a branch-vein. It is a fissure with the shape of a broad anticline

246 Mining Industry Of The Cceur D'Alenes, Idaho.

MINING INDUSTRY OP THE CGBUR d'aLENBS, IDAHO. 247

which dips very gently SW., nearly at right-angles to the strike of the great fissure. The actual intersection of this an- ticlinal deposit (which would be termed in Australia a " saddle- reef ") with the fissure has been destroyed by the erosion of Deadwood gulch ; but the deposit obeys in a general way the rule governing the other deposits along the Bunker Hill lode. From a point on the surface on the crest of the anticline, nearest the line of the main fissure, it slopes gently away down the crest and sides of the anticline, and, as it does so, it loses its ore, becomes more quartzose and ferruginous until, as in other deposits, nothing remains in it but quartz and iron.

This remarkable deposit, covering an area of 6 acres, has been worked out. The old mine-levels show the contours of the anticline. The ore was all oxidized, rich in silver, and from 6 in. to 6 ft. thick.

The Canyon Greek Lodes,

These are very different from the Bunker Hill. The fissures are much smaller, simpler, and more uniform. They are nearly vertical, rarely dipping less than 75° N". or S.

The Mammoth'Standard Vein. (See Figs. 6, 7, 16 and 17.)

This important lode has produced lead and silver of the gross value of about f 11,000,000, yielding at least $3,000,000 in dividends. It has been traced from the W. end-line of the Mammoth claim eastward to about 900 ft. E. of the line be- tween the Mammoth and the Standard, at which point it has been cut off by a considerable fault, and the continuation has not yet been found. The lode has proved productive for a length of 2400 ft ; and, by a curious coincidence, its richness seems to increase until its abrupt termination by the fault- plane above-mentioned. (See Fig. 6.)

The fissure strikes N. 65° W. (true), and dips about 77° K The quartzites along the fissure dip W. at a moderate angle, so that the vein cuts the formation nearly at right angles.

The fissure is a fault of moderate displacement. A well-de- fined plane of movement can always be found in the vein, some- times on one side, sometimes on the other, and often in the middle. As in the Bunker Hill lode, the ore immediately next the fissure shows a finer grain than that deposited further away.

248 MINING INDUSTRY OF THE C(EUR d'ALBNBS, IDAHO.

Fig. 7 shows the arrangement of the ore-hodies on the Stand- ard and Mammoth, as developed on the Campbell tunnel-level.

In the Standard mine, the vein has always two, and often three or more, well-marked ore-streaks ; but west of the Stand- ard ore-shoot there is seldom or never more than a single streak.

The ore-body mined on the Standard varies from 5 to 50 ft., and averages about 17 ft., in width. There are no defined lode- walls, the fissure invariably lying within the mineralized zone, and the mineralization having aftected the sheared rocks on either side. As a general rule, the rock on each side of the ore-body is sheared and crushed, for 3 ft. or more from the outer-

Fio. 6.

Sketch-Plan of the Mam moth -Standard Vein, and the Fault in the Standard

Ground.

most ore-streaks, to such a degree as to render the ground some- what loose and unstable. Beyond the limit of the sheared zone the country-rock is firm and unaltered except where it is affected by transverse faults. The parallel zones of sheared rock on each side of the ore make the walls very heavy and practically impossible to hold by timbering.

The Frisco Lode.

This interesting deposit has been disturbed by a number of cross-faults. The fissure proper is nowhere well marked, but the whole mass is firmly cemented together and the mineral is " frozen " to the walls.

MINING INDUSTRY OF THE C(EUR d'ALENES, IDAHO. 249

Methods of Operation.

The mining industry of the Cceur d'Alenes may be consid- ered under three heads : (1) The extraction of the ore from the ground, or actual mining; (2) the concentration or milling, which, at every property in the district, with two exceptions, includes transportation of several miles from mine to mill ; and (8) the shipment and sale of the concentrated ore.

In general terms, there is a loss in concentration of from 20

Fig. 7.

CroflB-Section, Showing Structure of Ore-Bodies in the Shear-Zone of the

Standard and Mammoth.

1. Gountrj-rock ; 2. Sheared rock outside of ore-body ; 3. Parallel streaks of

coarse galena and iron carbonate ; 4. The fissure carrying fine-grained galena ;

5. Streaks of barren, but silicified, country-rock lying within the vein. The

maximum and minimum widths of the shear-zone are 100 ft. and 15 ft. respectively.

to 30 per cent, of the gross values ; and the freight- and treat- ment-charges amount to 40 per cent, of the gross selling-price of the concentrates, leaving the mine-owner from 42 to 48 per -cent, of the gross value in the ore to cover the cost of mining and milling.

For example, I have said above that the ores mined in the district would average by assay about 10 per cent, in lead and 7 oz. silver per ton. The lead and silver are sold to the smelters,

250 MINING INDUSTRY OF THE C(EUR D'aLBNES, IDAHO.

say at " brokers' quotations," the smelters paying for 90 per cent, of the lead and 95 per cent of the silver in the ore. At present prices the gross value of the above-mentioned ore would be:

90 per cent, of 200 lbs. 180 lbs. lead, at 3.5 cts., . . $6.30 96 per cent, of 7 02. =6.66 oz. silver, at 56 cts., . . . 3.66

Totol $9.96

Of this total gross value, after deducting concentration-lossea and freight- and treatment-charges, the mine-owners' residuum of 42 to 48 per cent, amounts to from J4.20 to $4.80 per ton. The cost of mining and milling will be, under varying circum- stances, $2.60 to $3.50 per ton, and the net profit remaining will be, therefore, from $0.70 to $2.30 per ton.

Mining.

At least 70 per cent, of all the ore thus far mined in the Coeur d'Alenes has been extracted through tunnels without hoisting or pumping. Of the remaining 30 per cent., which has been hoisted, at least two-fifths has been hoisted through underground shafts, to be subsequently hauled out through tunnels. The Tiger-Poorman is the only mine which has al- ways been operated by shafts from the surface. This large proportion of tunnel-work has been a great advantage to the district.

There are many long and well-constructed tunnels, designed to serve for the final exploitation of the mines. The principal ones are : the Sweeney (Wardner, about 6000 ft. long) ; the Reed (Wardner, about 6600 ft.) ; the Kellogg (Wardner, about 12,000 ft.); the Frisco (Gem, about 1200 ft); the Standard (Mace, about 3000 ft.) ; the Mammoth No. 6 (Black Bear, about 3600 ft.) ; the Hecla No. 3 (Burke, about 2400 ft.) ; the Morn- ing No. 5 (MuUan, about 3000 ft.) ; and the Morning No. ft (MuUan, now being driven, 10,000 ft.).

Each of the mines operating the above tunnels has a num- ber of other adits, some of them of great length ; but these are of earlier and less elaborate construction, and serve for the working of upper levels.

The principal shafts of the district are the following : The Tiger-Poorman (sunk from surface 1700 ft.); the Hecla (80ft

MINING INDUSTRY OF THE C(EUR D'aLENES, IDAHO, 251

ft.) ; the Standard (in Campbell tunnel, 8000 ft. from the sur- face, and 850 ft. deep); and the Frisco (in Frisco tunnel, 1200 ft from surface, and 1400 ft. deep).

Measured vertically below the outcrops, the Tiger-Poorman the Standard and the Frisco mines are nearly of the same depth, 2000 ft. or more.

These three mines are equipped with Corliss hoisting-engines of the same make and size, which were made by Fraser & Chalmers, with 20 by 60 in. steam-cylinders, flat ropes and reels, designed to hoist as much as 2500 ft. They can be run with or without counter-balance, and are very good machines.

No mechanical devices of special interest are peculiar to the district, with the exception of an electric-light hoist-signal sys- tem, recently installed at the Standard mine by Doerr, Mitchell 4 Co., of Spokane. It is possible that this device may in time become more widely known and extensively used. It consists of a signal-box in the hoisting-room and at each station in the shift. Electric lights are placed in these boxes behind ground glasses, on which are marked the desired signals. Switch- boards placed near the boxes enable the station-tenders to turn on the signal lights, which burn until they are turned off by the engineer with a throw-out device. The chairs for landing the cages in the shaft are provided with an attachment which, when the chairs are thrown out to receive the cage, automati- cally turns on, in plain view of the engineer, a warning light, marked with the number of the level, at which the chairs are out. The signal-lights burn both in the stations from which the signals are given and in the engine-room. This enables the station-tender instantly to see and correct any false signal. It is practically impossible for the engineer to receive a false sig- nal ; and, as he knows the exact position of any chairs which may be out in the shaft, there is no excuse for his smashing cages.

Three methods of mining are used in the district : (1) back- stoping and timbering; (2) back-stoping, timbering and fill- ing ; and (3) back-stoping and filling without timbering. A description of the methods used at one or two representative mines will perhaps be more instructive than any general ac- count.

At the Bunker Hill and Sullivan, the most interesting fea-

252 MINING INDUSTRY OF THE GCBUR D'aLENES, IDAHO.

ture of the underground mining is the extraction of wide bodies of low-grade ore by stopes which are filled, as the work pro- gresses, with waste rock sorted from the broken ore. There is usually more than enough of such material to keep the stopes fall, and provision has to be made for tramming the surplus waste away. Sometimes this back-stoping is done without any timbering, other than an occasional prop to support a sus- picious-looking piece of ground in the roof; 'but more com- monly the stopes are timbered with light square sets. (See Fig. 8.)

In stoping the ore at the Standard (see Fig. 9), it has been found necessary to fill up the stopes with barren material from the vein. This is done by the simple process of sorting out part of the waste rock from the barren streaks and from the walls, and throwing it down among the timbers below. It is quite easy, in most parts of the mine, to secure in this way enough filling to keep the stopes full within two or three floors of the back. As the levels are 200 ft. apart, it is necessary, to build massive cribbed chutes up through the timbers.

The timbers are of two kinds — square sets and stuU-sets. The square sets are 9 by 5 by 6 ft., and are built in the usual way. The stull-sets are merely caps, cut, if possible, long enough to reach from wall to wall, set horizontally and sup- ported by two posts. If the vein is over 15ft. wide, the cap is made in two sections, joined together on a third post. Three- inch plank is used for flooring or lagging.

The timbering has always been massive and elaborate. Only the abundant supply of cheap timber, which is one of the ad- vantages of the region, renders such heavy timbering econom- ical.

Every facility is provided for the easy handling of the tim- bers inside and outside of the mine. Each level is equipped with two good hoists, operated by compressed air, to hoist the pieces into the stopes. To provide for these hoists and for the ropes and sheaves, the first floor above the track floor is left open and free from filling.

In the Mammoth mine, the ore almost invariably lies in a single streak in immediate contact with the fissure. The shear-zone is much narrower than elsewhere ; and the mining is simpler, in that no filling on an extensive scale is required.

MINING INDUSTRY OF THE CCEUR D'aLENBS, IDAHO. 253

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Sketch, Showing Method of MiniDg at the Standard Mine, Idaho, by Means of Stall-Sets and Filling.

Mining Industbt Of Thb C(Eur D'Alenbs, Idaho. 255

All the material broken is sent to the mill as concentrating-ore. The timbering consists entirely of stull-sets, with 6 ft. posts (instead of 8 ft., as in the Standard). The chutes are built of planks, instead of the cribbing which is necessary when the stopes are to be filled.

At the Tiger-Poorman, Hecla, Frisco and Morning mines, all the stoping is done with stull-sets, about as in the Mam- moth. Very little efibrt is made to sort the ore before concen- trating, or to fill the stopes systematically. It is an open ques- tion whether it would not pay better to give more attention to sorting and filling, and less to timbering. With closer sorting the concentrates might be obtained by the milling and trans- portation of less material ; and, as an additional advantage, the stopes would be left in a safer condition.

Use of Water-Power.

All the mines make more or less extensive use of the excel- lent water-power of the region. An enterprise is now on foot to supply any deficiency of power by means of a 90-mile electric transmission from Spokane Falls. It is expected that, in view of the high cost of coal, this will prove cheaper than steam power. Practically all the power fi*om the neighboring streams is now utilized for running mills, generating electric power, and compressing air.

At three of the principal properties elaborate and interest- ing water-power plants have been installed ; but, by reason of the variation in the water-supply during the year, each plant is, to a greater or smaller extent, supplemented by steam- power.

At the Tiger-Poorman mine, on Canyon creek, electric power, generated by water-power, is used for pumping on a large scale. The pumping-station is more than 1500 ft. below the surface, and the pumps raise the water through that distance in one lift. The plant was built by Nordberg, of Milwaukee, and consists of two independent pumps, which can be run either by steam or electricity, or both. The steam-engines are 18 by 30 by 36 in. cross-compound condensing-engines. The electric motors are each 200 H. P., alternating, 40-cycle, induc- tion-motors, using a current of 2300 amperes, which is brought down the shaft to the machines by a 2{-in. submarine cable.

256 MINING INDUSTRY OF THE CCEUR d'aLENES, IDAHO.

The pumps are geared, have by 36-in. plungers, and fly- wheels, 16 ft. in diameter, which carry 30-in. belts. These pumps have eflTected a vast economy in the operation of the mine. They raise from 400 to 1200 gallons (averaging about 500 gallons) of water per minute.

The Morning Mining and Milling Company (see Fig. 15) employs in exploitation a thoroughly well-planned power-sys- tem, most of which is used for making compressed air. The water is gathered from various streams high up on the moun- tains above the compressor-site, and conveyed to the wheels by three pipe-lines of 1400-, 1200- and 130-ft. head, respectively. The 1400-ft. and 1200-ft. heads are delivered by separate noz- zles on a Pelton wheel 32J ft. in diaineter. The 130-ft. head is used to drive two 11-ft. Pelton wheels, one on each side of the big one and on the same shaft. There are two compressors, one on each end of the water-wheel shaft. They have com-, pound 18 by 32 J by 42 in. cylinders, with intercoolers. The air is compressed to 28 lbs. in the low-pressure cylinder, and delivered by the high-pressure cylinder at 90 lbs. Running at full speed, these machines compress about 6000 cub. ft. of free air per minute. The pipes which convey this air to the mine cost more than the machinery. They comprise 9200 ft. of 12J- in. pipe, to No. 6 tunnel, at which point the air is divided into two lines of 9-in. pipe, one entering No. 6 tunnel, which will be 2 miles long, and another leading 4J miles to No. 5 tunnel.

The Bunker Hill and Sullivan Mining and Concentrating Company also uses water-power to help run its large compres- sor at Kellogg.

Milling.

The process employed is substantially the same at all the mines, and consists of coarse crushing and separation by jigs. Most of the ores contain the galena in segregated streaks of practically clean material, which separates under crushing and is easily caught. The difficulty increases greatly when the galena is intimately mixed with iron carbonate, zinc-blende and quartz. Such ores require much finer crushing, and the use of a much greater number of vanners, buddies, shaking- tables, etc., to separate the slimes. Fig. 18 is an outside view of the Mammoth mill, and Fig. 19 shows the Helena and Frisco mills. The following description of the process at the Stand-

MINING INDUSTRY OF THE CCEUR D'aLENES, IDAHO. 257

258 MINING INDUSTRY OF THE CCEUR d'aLENES, IDAHO.

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Mining Industry Of The Cceur D'Albnbs, Idaho. 269

ard mill will serve as a concrete example of the best current practice :

The crude ore from the mine is dumped from railroad-cars into a bin of about 600 tons' capacity, whence it is fed by gravity to a No. 5 Gates crusher, which reduces it to something ovei 1 in., diam. From the crusher a 15-in. beltrconveyor car- ries it to another bin, whence it passes by gravity to the rough- ing-roUs, which reduce it to pieces of J to f in. diam. From the roughing-rolls it is elevated to a double set of trommel- screens, which size it into an " oversize " of more than 15 mm. diam., and into sizes which pass through 15, 10, 7 and 3 mm. screens. The fines which pass the 3 mm. screens are not jigged, but go at once to V-boxes or hydraulic classifiers. The slimes passing over the V-boxes go to settling-tanks, where the heavier material is caught and sent to Wilfley tables and Frue vanners. All the tailings from Wilfleys and vanners, together with the overflow from the settling-tanks, go to a " canvas plant of 52 tables of 6 sq. yd. each. Material caught on the canvas-tables is reconcentrated on two Wilfley tables.

Returning to the coarse material classified by the trommels, the oversize, or what passes over the 15 mm. screens, goes to the coarse or " bull '' jigs, and what passes through the 16, 10 and 7 mm. screens goes to finer jigs.

Part of the tailings from the coarse jigs is retained as " mid- dlings," to be further treated, and part is allowed to go directly to the creek as worthless. The middlings thus saved are passed through fine rolls and then to Huntington mills, which reduce the pulp until it passes a 40-me8h screen.

The finer jigs, Le. the 15, 10, 7 and 5 mm. jigs, also select a percentage of " middlings," which are likewise passed through fine rolls, in three sets, according to the coarseness of the ma- terial. Thence this material passes to the " middling " jigs, which take out some clean ore. All of the tailings from these " middling " jigs are reground in another set of Huntingtons to 40-mesh. All the material ground by the Huntington mills goes to the Wilfley tables and Frue vanners with the slimes from the settling-tanks and V-boxes above described.

This mill concentrates about 500 tons of crude ore per day; Its machinery consists of the following : a No. 5 Gates crusher ; two 15-in. belt-conveyors; six sets of 15- by 26-in. belt-rolls.;

Vol. Xxxmi.— 17

270 Mining Industry Op The Cceur D'Albnbs, Idaho.

four 6-fl. Huntington mills; twenty-eight Hartz jigs, arranged in 14 pairs ; 2 lines of trommels ; an " oversize " trommel, for middlings; 4 elevators; 18 Wilfley tables; three 4-ft. Frue vanners ; and 52 canvas tables.

Power for the main mill is derived from two Pel ton wheels, one of 4 fk. diam. under a 82-ft. head, and one of 6 ft. diam. under 285.ft head. A third (24-in.) Pelton, under 285-ft. head, runs a dynamo for electric lighting, and a fourth runs the Gates crusher.

TransporiaMon.

The transportation of crude ore to the mills is a problem of considerable importance to all the mines except the Tiger-Poor- man, the Frisco and the Crown Point, each of which has its mill at the place where the ore reaches the surface. The ore from the Standard, Hecla, Mammoth and Empire State is hauled to the mills by the Northern Pacific and Oregon Railway A Navigation Co. railroads, which reach the mine, and do the work for a reasonable price. The Bunker Hill and Sullivan has a Bleichert tramway (see Fig. 14) about 2J miles long. The Morning Mining and Milling Company (see Fig. 1 5) has a railroad of its own, several miles long, built on a 7 per cent, grade, and operated by means of Shea geared locomotives. It has proved very successful, hauling the ores to the mill for less than ten cents a ton, inclusive of delivery of all timber and other sup- plies to the mine.

The cost of transportation varies from 8 to 20 cents per ton at the various mines.

Fig. 21 shows one of the eftects of the labor-troubles in this region, any recurrence of which is earnestly to be deprecated by all parties. This is not the place to discuss the merits of such controversies ; but the condemnation of such destructive and lawless violence as is here illustrated should certainly be endorsed by citizens of all political parties and schools of polit- ical economy or sociology.

Progress and Prospect of Development.

It is reasonable to expect that the CoBur d'Alene district will be able to maintain its present, and perhaps an increased, out- put for many years to come. Within the past two years three new properties have been opened up and brought to the divi-

Mining Industry Of Thb C(Bur D'Albnbs, Idaho. 271

dend-paying stage, while several others have shown more or less ore, and are likely to develop satisfactorily.

The Hercules, which is the latest discovery of great im- portance, promises to become a mine of the first rank. This vein is at the upper end of Canyon creek, high on the side of Tiger peak. Near the surface the lead-values have apparently been destroyed by leaching ; but at the depth of some 400 ft. the ores are found to be very rich both in lead and silver. This is a good instance of that reconcentration of values near the surface which is beginning to be recognized by students of ore-deposits as an important feature in the value of many metal-mines

Up to date the Hercules has not reached the point of con- centrating its ores, but ships them crude, at a very handsome profit

NoTB. — With regard to the probable extension of the Bunker Hill lode northwestward to the Crown Point, I wish to say that since the body of the text was written a more careful study of the conditions leads me to think that the lode does not pass westward of Dead wood gulch. In saying this, I mean to refer to the lode as a well-defined structural feature. Certain min- eralization is found along a course extending between the Viola and the Crown Point; but this is in isolated, disconnected places, and should be considered more properly as belonging to a mineral district than to a distinct vein.

272 Coking In Bbe-Hive Ovens With Reference To Yield.

Coking in Bee- Hive Ovens with Reference to Yield.

BY CHARLES CATLETT, STAUNTON, VA. (New Haven Meeting, October, 1902.)

My attention having been called several years ago to the possibility of increasing the yield of coke per ton of coal, as obtained in certain bee-hive ovens, I called the attention of the Institute to the matter at the New York meeting in 1899. I have had occasion since to witness the indifference with which this matter is ordinarily considered, and, on the other hand, the marked improvement which comes from even a most per- functory effort in that direction ; and I am almost tempted to say that nothing in connection with the coking of coal is at present so important. There are other factors, which are fun- damental and necessary; but they have been considered al- ready ; while the question of yield is, as a rule, absolutely ignored, or some figure is taken as the result of a special burn- ing of one or two ovens, and the assumption is made that the whole battery is yielding at that rate. The uncertainty of this assumption I may illustrate by saying that, in my own observa- tion, the burning of a single oven in a battery frequently gives, by actual weight, as much as 69 or 70 per cent, of merchants able coke, while the battery as a whole was yielding only an average of 63 per cent.

Only from careful records, checked at least once a month, ot the weight of the coal going to the ovens and the weight ot coke produced, can any correct idea of the actual yield be gained, or methods be modified so as to produce good results ; yet, as a rule, the crudest estimates are usually the only avail- able data. In many cases there are reasons for this loose prac- tice. The coal is mined by measurement; the payment for drawing the ovens is in proportion to the amount of coal which goes to them ; and, not uncommonly, the royalty is so much a ton of coke, not of coal. The mine-manager is tempted to in- crease the volume of coal mined which is paid for as a ton, and to do the same thing in charging the ovens. Nor does he

Coking In Bbb-Hive Ovens With Reference To Yield. 278

wish the royalty-charge to be changed in any way. The result is that often his records do not truly show within quite a large percentage the actual weight of coal mined and charged in his ovens. Yet until he has accurate information on this point, he cannot tell what is the amount of loss under present methods, or how to improve on them. I venture the assertion that the owners of many plants in the Connellsville region, otherwise well managed, who complacently accept Mr. Fulton's statement that the yield of the Connellsville coal in coke is 66 per cent, would be astonished should they ascertain what is their actual yield.

The eflFect of a slight increase in the yield per cent, is greater than is usually realized. For instance, if a battery of ovens is yielding 60 per cent., and the yield is increased to 61 per cent., there has been an absolute saving of one-sixtieth, or 1.66 per cent, of the toted value of the coke formerly produced less the cost of loading, — since all the other expenses remain the same. I have never yet examined a battery of ovens, where the attention of the management had not been called to the yield, in which it was not possible to make an increase of from 8 to 5 per cent. If, for purposes of illustration, we assume that the former yield was 60 per cent, (which figure does not vary greatly from the general practice), the saving of 8 per cent, would mean a total saving of of the output, and a saving of 5 per cent, would mean a total saving of of the output. Enormous as this dif- ference may seem, it is exceedingly common, and at times is greatly exceeded. I know of a coking-district which, as a whole, is only yielding 55 or 56 per cent., though the coal could readily be made to yield from 65 to 70 per cent.

The loss of the by-products in the 63,000 bee-hive coke- ovens in this country is an appalling waste of natural supplies, and has been a fruitful source of discussion as to the waste- ftilness of our methods. If, however, I am right in my belief that my own experience fairly represents the conditions at the majority of the ovens in operation, there are at least 1,000,000 to 2,000,000 tons of coke annually consumed and lost in our bee-hive ovens which, by anything like reasonable care and attention, could be saved. As the average value of coke in 1901 was more than (2 per ton, this represents a very large money value.

274 Coking In Bbe-Hivb Ovens With Reference To Yield.

This waste is worse than useless. The excess of heat avail- able from the gases, as shown by tests of a great variety of coals in the retort-ovens and ordinary tests of single bee-hive ovens, demonstrates to my mind that there is not a good coking-coal which could not be coked in bee-hive ovens by the heat derived from the combustion of its gases alone, and that the burning up of any coke, which has already been formed, is therefore a positive, unnecessary loss.

But more than that : the burning of a portion of the coke necessarily results in the deposition of ash on the remainder. This retards the transmission of heat from the hottest portion of the oven (just above the coke) to the unburnt portion of the coke toward the bottom of the oven ; and, moreover, when the oven is watered down, this ash is washed through the pores of the coke and retained there, thus increasing the ash beyond its normal and proper proportion. A careful examination will disclose this ash in the pores of the coke. I have known cases, where the coal was naturally high in ash (and therefore the ash- content was a matter of the greatest importance), in which enough coke was consumed to add 4 per cent, of ash to the entire product. In nearly all cases the increase of ash due to the burning of coke is conspicuous.

The theoretical yield of the coke can be determined within a fair degree of exactness from the proximate analysis of the coal. The coke carries all the ash and fixed carbon, and, even under the best work, a certain portion of volatile matter and moisture. The sulphur will probably be distributed in the coke, as indicated in the analysis. In other words, a coal of the following composition : Moisture, 1.25 ; volatile matter, 26.30; fixed carbon, 66.05; and ash, 6.40; total, 100— may be expected to give a theoretical yield of 66.05 + 6.40 72.45 per cent, of coke. To this should be added at least 1 per cent, for the moisture and volatile matter, which are retained by average " good coke," so that the theoretical yield of coke made from the above coal can be assumed to be 78.45 per cent Dividing the fixed carbon, ash and 1 per cent, of moisture and volatile matter by that figure, we would get, for the coke made from this coal: Fixed carbon, 89.92; ash, 8.71; volatile matter and moisture, 1.86 ; total, 99.99.

In careftilly-burned ovens, the ash should not be increased

Coking In Bbb-Hivb Ovens With Repbrbnce To Yield. 276

or the carbon reduced by more than 0.5 per cent from the figures obtained by calculations like the above, and the volatile matter and moisture may both be reduced below the above figures, though they are often greater. There are various mod ifying factors, the exact measure of which cannot be accurately determined. Among these is the deposit of carbon from de- composition of the gases. The amount of ash is inversely pro- portional to the yield, so that increase in the yield at the same time decreases the ash. It is not uncommon to claim an ad- vantage from an increase in a coke, up to a certain point, of ash of suitable composition, as a means of hardening the structure ; but I suppose no one will claim any advantage from the ash which does not form part of the structure, but is simply de- rived from outside sources, either by collection or otherwise. This latter ash is simply paid for as coke, and then must be got rid of. It must not be confounded with that which enters into the structure.

Aftr the coal goes to the ovens, there are several ways in which the ash in the coke produced may be increased above the theoretical amount. A portion may be derived from the dirt-filling around the tunnel-head ; a portion from forking the coke from a dirty yard ; a small amount from impure water used in quenching ; but by far the larger amount comes from the aahes of the coke burnt up in the oven. As the latter is almost in reverse proportion to the yield, it is obvious that the advantage of yield is not confined entirely to the saving of coke, but goes hand in hand with improved quality.

The " commercial " yield will be determined by local con- ditions and the character of the particular coal. It is the theo- retical yield, less the losses in burning and of fine coke in handling, and increased by the ashes and dirt gathered as noted above.

In good coking-coals, high in volatile matter, the "breeze'* or fine coke will run 2 or 8 per cent., and the commercial yield should not be more than from 8 to 5 per cent, below the theo- retical. It is possible to do better, but anything less good may be considered bad practice. With higher fixed carbon in the coal, and particularly when the coal is low in ash, and will burn or " cut " readily by small leaks admitting air, the difference between the theoretical and the commercial yield may be

276 Coking In Bbe-Hivb Ovbns With Rbfbbbnce To Yield.

between 5 and 10 per cent. ; but first-class work should approx* imate the former figure.

The question of yield is involved to a greater or less extent in all the operations connected handling the coke-ovens. The conditions which permit of the greatest regularity of drawing and charging, in which the leveling is done as it should be, the ovens are watered down to the best advantage, and are worked to their capacity, etc., are all factors affecting the yield. A plant in which the discipline and management is good will naturally have a better yield than where the manage- ment is lax; but after all this is said, there still remains the difference due peculiarly to a special effort, or want of effort, in the way of handling the draft and the oven with special reference to this point.

The principal thing which affects the question of yield is the care and skill with which the drafting, or admission and exclu- sion of air to the oven, is controlled.

The object and purpose of the drafting is to secure a satisfac- tory degree of heat at the right time, and as nearly as possible to secure this heat from the gases which are driven off during the process of coking, and which would otherwise be entirely wasted. The more nearly it is possible to completely burn out the coke at a satisfactory temperature, and leave the ovens in first-class condition for the next charge, without burning any of the coke which has been formed, the more nearly do we attain perfect results. The mistake is commonly made of as- suming that at all stages of the process, whatever may be the condition of the oven, an increase of draft means an increase of temperature and a decrease of draft a decrease of tempera- ture. The most casual examination will show that this is not the case. At the first stage of the burning, before the gases which will add to the heat by their combustion have com- menced to come off, it is possible to cool the oven by excessive draft; and it is common and advisable practice to cover the ovens immediately after drawing, and re-cover them after charging, with a view to their " catching-up " more rapidly. By this means the heat stored in the walls finds its way to the inside of the oven. There is apt to be a time, within the first twelve hours after an oven has " caught-up," when the amount of gas formed is in excess of the ability of anything like an

GOKINa IN BEE-HIVE OVENS WITH REFERENCE TO TIELD. 277

ordinary draft-orifice to fiirnish the necessary air to retain the oven at a temperature for perfect combustion. During this time, also, the tunnel-head of ordinary size has great difficulty in disposing of the products of combustion. Later in the pro- cess, this condition is reversed, and the amount of air is apt to be in excess of what is necessary to burn the gases which are ooming off; and, finally, if the draft is not changed, it becomes greatly in excess of the requirements of the ovens. ¥tom this stage to the end of the burning it is thoroughly possible for an oven to continue to cool, even with the admission of a large volume of air. In other words, the heat furnished by the small amount of gas which is coming off, and from the con- sumption of a portion of the coke, is less than the lowering of temperature caused by the loss of heat from the tunnel-head and from radiation ; and this difference is increased by increas- ing the draft. The attempt to hurry an oven which has been allowed to cool, and which is continuing to cool, while exhibit- ing a number of " candles," by giving to it an excess of draft, is often indulged in ; but it will be found very much better to endeavor to burn the oven so as to keep the heat up to a max- imum towards the end of the blast, at the time when it is needed most to reach the coal at the bottom of the oven, rather than to try to replace the heat by an effort to burn a portion of the coke. This effort is always disappointing in results. As a general proposition, I should say that, in nine times out of ten, the drafting is too heavy, and the oven can be brought out in better shape by a more uniform drafting extending over a longer period. As a rule, from 20 to 26 sq. in., in the form of circular draft at the top of the door (which may be as much as 40 in. high), will be ample for the largest oven which it may be desirous to burn out, while this should be reduced by at least one, or possibly two, changes as the oven is burnt out, so that the amount of air shall at no time be greatly in excess of what is necessary to completely and clearly burn off the -escaping gas.

As a rule, I should say that the tendency is to make the tuBuel-heads too large. Of course, they have to be large enough to take with sufficient promptness the coal from the larries ; but the standard forms of larry will readily discharge into an opening 12 in. in diameter, and I have never yet seen

278 Coking In Bbb-Hive Ovens With Reference To Yield.

an oven or a coal which would not give better results with an orifice of that size than with a larger one. Yet larger sizes are common. I know of one manufacturer whose standard size is 16 in., or nearly twice the area of a 12-in. tunnel-head. The latter is abundantly able to carry off, under the best con- ditions of drafting, the products of combustion ; and any excess above this very materially increases the loss of heat, and inter- feres with the efficiency of the oven.

The small-sized opening may be slightly inadequate at the beginning of the blast; but as the gases come off in smaller quantity and more slowly, it is invaluable in retaining the heat so much needed at the later stage. The smallest tunnel-head I have tried for a 12-ft. oven was 11 in. in diameter; and the results were fairly good. The ordinary difficulties connected with prompt charging limit the size to 12 in. and upward, and I believe that the smallest size that can be readily handled by the charging facilities will be found the best.

The use of lids is extremely desirable. Properly handled,, they mean a great deal as regards the matter of yield. The retention of heat in the oven is, of course, of the Utmost im- portance. The ovens should be covered as soon as drawn. They should be covered when charged until they are " caught up;" and as soon as the oven is practically burnt out, the draft should be cut off entirely, and the tunnel-head partially or entirely closed. This will aid in retaining the ovens in the best possible condition, and will prevent the burning up of a large amount of coke. Particularly should the doors and jambs be kept tight, and the smallest cracks stopped. The consumption of coke from this cause is enormously larger than would be supposed at first sight.

It is almost impossible to make any improvement in the matter of yield without keeping records in such shape as to- show what are the good or bad results of any method of treat- ment. It is absolutely necessary, therefore, that arrangements be made to calculate, from either the railroad- or the larry- weights, to within at least 0.25 per cent, of the actual yield, within one or two days from the end of each month. With this, there is the strongest incentive to endeavor to improve ; and without it, there is the strongest reason for making no change,, since it cannot be known whether a change is advantageous or

Ookinq In Bbb-Hive Ovens With Rbfbrbncb To Yield. 279

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280 Coking In Beb-Hivb Ovbns With Reference To Yield.

not. It is impossible to give a form for such a record, because it will vary with each plant ; but I would call attention to the fact that that portion of the coke and coal on the yard or in bins, or in transit at the beginning and end of each month, if carefully estimated, cannot introduce a large error; and any such error which is made one month is balanced in the suc- ceeding months ; so that, if actual weights be taken of the coal that goes to the ovens and the coke that is shipped away in each month, the other amounts being estimated, the results will be very close.

I submit the form on page 279 as a valuable one for keeping the monthly record and comparing the work month by month. It is a copy of a report from a plant in actual operation.

The monthly efficiency-record will be found by multiplying the efficiency per cent of yield ; the efficiency per cent of coal; and the efficiency per cent, of the number of ovens drawn, and will no doubt astonish some coke-makers when they apply this form to their own operations. The theoretical yield is determined as explained above; and the practical yield is something smaller, depending on the tendency to make fine materials or " breeze," the composition of the coal, the condition of the ovens and equipment, etc.

As promptness and regularity in all the steps of the coke- manufacture are essential for high yield, the following form of daily report will be found of service in locating promptly weak points in the work. It should be transferred to a scratcher in the office in such form that the percentage for each day follows that of the previous day in a vertical column, and changes can be noticed at a glance.

Coke Department — Daily Efficiency-Record.

Efficiency-Record.

Drafting :

Required.

Actual.

Per cent

Ovens burnt out on time,

. A

B

Ovens ready to draw, .

D

Ovens standing over, .

. E

F

Drawing :

Number of ovens, .

. G

H

Promptness (hours),

J

Coal Supply :

1

Number of larries,

. K

Charging :

Number of larries,

. M

N

Promptness (hours),

P

Coking In Bee-Hive Ovens With Reference To Tield. 281

Loading Coke : Required. Actual.

Gars famiflhed, Q R

Cars loaded, S T

Loaders, U V

A. The number of ovens charged to come out to-day.

B. The number of ovens charged to come out to-day, which came out in th& proper time.

C The ovens charged to come out to-day and those brought over from previous days.

D. All ovens ready to pull at the proper time. K Is always zero.

F. The ovens ready to pull at the proper time which were not pulled.

G. All ovens ready to puU at the proper hour. The number is the same as D. H. Number of ovens pulled.

I. Number of hours from the time the first oven is started until the last is finished.

K. The number of larries of coal needed to supply the ovens that should have- been drawn that day. L, the number available.

M. The number of larries of coal needed to charge the ovens drawn that day.

O. The number is the same as I. The larries used in charging start later, but should not take a greater number of hours than are required for drawing.

Q. The number of cars asked for from the railroad company. It is seldom less,, and is often more than the number required for one day's output of coke.

B. The number of cars furnished.

S. The number of cars to be loaded— evidently the same number as R.

U. Is the number of loaders required to load B.

V. The actual number of loaders.

Note. — The "efficiency-record percent." maybe illustrated as follows: Sup- pose A is 100 and B 75 ; then the efficiency-record of ovens burnt out on time " is 75. If 25 ovens were left over from the previous day, the full number which should have been ready to draw to-day (C) would be 100 -f 25 125 ; but as 25 ovens were not burnt out, D is only 100, and the record percent of " ovens ready to draw '' is 80. '' Ovens standing over " may be due to defective drafting, failure to draw, or other causes. As E is always zero, it is not practicable to represent the ratio between £ and F by percentage. Under "drawing,'' G to-day is 100, and if only 65 (H) are drawn, the percentage efficiency on this line would be 65. If I should be 8 hours and J is 10 hours, the efficiency-record per cent, for " prompt- ness '' would be only 80. The coal-supply should always be enough for the regu- lar number of ovens due each morning, or 100 (K), but if there is only coal enough for 90 (L), the efficiency-record per cent, of coal-supply would be only 90. The total amount of coal actually needed on any day might be more or less than the normaL To-day M would be only 65, and if N is 65, the charging efficiency- record per cent, is 100. O should in this case be 8, and if P were 12, the " ef- ficiency-record per cenf of promptness in charging would be only 66.66. If Q is 10, and B is 5, the car-supply for the day is only 50 per cent, of what it should be, and if S is 5 and T is 3, then the loading of cars furnished is only 60 per cent, of what it should be. IT and V simply enable the superintendent to know whether th failure in loading is due to want of men or from some other cause. The effi- ciency for the day is in the following order : Car-supply, 50 ; loading cars, 60 ; drawing, 65 ; promptness in charging, 66.66 ; ovens burnt out on time, 75 ; prompt- ness in drawing, 80 ; normal coal-supply, 90 ; charging, 100. The weakest points in the actual operation of the ovens are " Drawing '' and " Ovens burnt out and the normal coal-supply and promptness should also be looked after. As the coke- bofls is usually not strong at figures, the report should be turned in, and the per- centage calculated at the office.

282 Notes On Brazilian Gold-Ores.

Notes on Brazilian Gold-Ores.

BT ORVILLE A. DERBY, SlO PAULO, BRAZIL. With Introduction by Prof. J. F. Kemp, New York City. (New York and Philadelphia Meeting, Febraary and May, 1902.)

Introduction.

These notes, received by me from the author, who is not at present a member of the Institute, are presented as having a special interest for students of the genesis of ore deposits. The statements of Mr. Derby under the head of " Gold in Granitic Apophyses " show that, in Brazil, certain pegmatites are metal- liferous. In the United States, pronounced dikes or veins of this type have not been found productive.* — J. F. K.

In view of the recent important discussions before this In- stitute on the genesis of metalliferous deposits, certain features in the occurrence of gold which seem to be more clearly developed in Brazil than elsewhere can hardly fail to be of interest. As the observations here recorded have necessarily been of a somewhat cursory character, they will be presented in the form of brief notes, without any attempt to draw con- clusions as to their genetic significance.

GMd in Gneiss. — The statement made by me many years agof that in the districts of Campanha and Sao Gon9alo, in southern Minas Geraes, gold occurs in gneiss, can now be re- affirmed in the most positive manner, on the strength of a recent examination of fresh material, confirmed by the testi- mony of an experienced mining captain fipom the Morro Velho mine, who, being skeptical on this point, made a prospecting- tour in the district. The specimens examined, though so far decomposed as to be readily disaggregated, were clearly of

See Lindgren on "The Character and Genesis of Certain Contact-Deposits/' Trans., xxxi., 242. t Am, Jour. Sou, 1884,- vol. cixviii., p. 443.

Notes On Brazilian Gold-Orbs. 283

typical gneiss, with the characteristics of a sheared granite, composed principally of feldspar and quartz, nearly free from mica, and showing no evidence of having contained more pyrites than the infinitesimal proportion usual in such rocks. Test-pieces, broken with the greatest care from the center of large blocks, so as to give perfectly fresh fractured surfaces, and to be free from open joints and quartz veins (even micro- scopic ones), were crushed and washed in porcelain vessels to avoid all possibility of any foreign admixture. Under these circumstances, samples of the size of a butternut were gener- ally found sufficient to give distinct colors of gold in very fine, but often beautifully crystallized granules.

The heavy residue was composed principally of zircon, in beautifully sharp and splendent crystals, showing no signs of wear — a character which confirmed the supposed granitic origin of the rock. The iron oxides, magnetite and ilmenite, which usually occur in such rocks, were unusually scanty in amount; and no pyrite, either fresh or altered to limonite, could be detected under the microscope. The amount of gold in the specimens examined was calculated at from 5 to 10 grammes per metric ton ; but from the extent of the old work- ings it is evident that much richer rock occurs in the district, which at one time rivaled in production the more celebrated auriferous districts of the same State, which are characterized by sulphide ores. This mode of occurrence, independent of sulphides, and more or less independent of quartz-veins as well, seems to predominate throughout the district.

Grold in Granitic Apophyses, — Aside from the well-known ex- ample of the Passagem Lode, so minutely studied by Dr. Hus- sak, a number of others of somewhat different character occurring in the same range have been briefly discussed else- where by the writer.* These, having the appearance of ordinary quartz- veins, are characterized by included patches of kaolin- ized feldspar, or of mica, carrying one or more of the charac- teristic granitic accessories, zircon, monazite and xenotime, and are evidently extreme phases of granitic (pegmatitic) dikes and stringers. Throughout the Diamantina district it is rare to see an outcrop of these veins which does not show signs of having

Am. Jour. Sci., 1899, vol. clvii., p. 343.

284 Notes On Brazilian Gold-Ores.

been worked, or at least prospected, for gold. The only one examined t"hat is certainly gold-bearing was close to the great diamond-working of Sao Joao da Chapada, in which a fine example of the quartz-kaolin type is presented. This cuts a somewhat sheared diabase, and consists of vein-quartz of the ordinary aspect, with partings and patches of green muscovite, which give an abundant residue of rutile and monazite. A lode which has been quite extensively worked at Bandeirinha about 20 miles to the southward, is believed to be of this char- acter, since the concentrated sand gives an abundSance of beau- tifully fresh monazite of the peculiar prismatic type described in the above-mentioned paper. Unfortunately, this mine could not be examined.

Gold in Lodes of Sulphides and Carbonates. — The great mine of Morro Velho, in the Sabard district of Minas Geraes,* is of this character, as are also the adjacent mine of Raposos and that of Cuyabd (at least as regards its main lode), about 10 miles distant. All these belong to the St John del Rey Mining Co. The sulphides are pyrite, pyrrhotite, arsenopyrite and chalco- pyrite — zinc-blende and galena occurring only as great rarities. The gangue is a finely granular mixture of carbonates of iron, magnesia and lime (siderite, dolomite and calcite, apparently in this order of abundance), with quartz and apparently also a feldspar, albite, which in the mass of the ore is distinguishable with difficulty from the quartz, but appears in great perfection and beauty in the vugs. Typical vein-quartz occurs only in subordinate amounts and local developments.

The country-rock at all three mines is a highly-sheared calc- schist, which, on account of the development of micaceous or chloritic elements, has generally been taken for a micaceous schist, and in which it is interesting to note that the pre- dominant carbonate is that of lime — those of magnesia and iron being very subordinate in amount, if not entirely absent. The gold-tenor runs about 12 to 20 grammes per ton at Papo- sos and Cuyab4, and about twice as much at Morro Velho. The lodes are characterized by great size, particularly in width , that of Morro Velho, which has been more fully opened up, having been worked for about 600 ft. in length with a very

An excellent account of this mine will be found in the Eing. and Min. Jour., vol. Ixxii., p. 485, Oct. 19, 1901.

Notes On Brazilian Gold-Orbs. 285

uniform cross-section, having a mean width of about 45 ft., to the depth of more than a mile on the dip, or 3100 ft. vertically below the shaft-mouth.

According to notes kindly furnished, from a considerable series of analyses, by Mr. Wilder, the chief metallurgist at Morro Velho, the ore contains 30 to 40 per cent of sulphides, 30 to 40 of carbonates, and 20 to 30 of quartz. Pyrrhotite is the predominant sulphide ; siderite the predominant carbonate. In an assay-sample, representing the ore put into the bins dur- ing a period of several months, the pyrrhotite was determined by Mr. Wilder at 28.5 per cent. The other sulphides were calculated as follows: arsenopyrite, 5.04; pyrite, 2.50; chalco- pyrite, 0.66 per cent., giving 36.70 per cent, for the total sul- phides. In this sample the residue insoluble in acids (mainly quartz) amounted to 24.10, leaving 39.20 per cent, for the car- bonates. In the lean portions of the ore the carbonates increase in proportion at the expense of both the sulphides and the quartz; and the miners consider that a fair amount of silica, shown by small, scattered eyes of smoky quartz, is a favorable indication of good ore. When, however, the quartz becomes excessive, and the lode-stuft' takes on the appearance of ordinary vein-quartz, the contents in sulphides and gold run low. Also, when the pyrite runs high, the gold-value seems to sink.

To test the prevailing impression that an abundance ot arsenopyrite is a favorable indication for gold-value, Mr. Wilder constructed the gold- and arsenic-curves of a large number of assays, with the result that he found divergences quite as frequent as coincidences.

A certain proper mixture of the various sulphides and of the carbonates and quartz of the gangue seems to give the best values. A thin line, characterized by lead sulphide, gave most extraordinary values ; but it soon ran out, and no other like it has been known within the experience of the present staff.

At Morro Velho the ore, except as to variations in the rela- tive amounts of the various constituents, presents no well- marked differences in structure and composition throughout the immense mass. At the other two mines, a considerable part of the lodes is constituted by an exceedingly hard, jaspery VOL. .—lB

286 Notes On Brazilian Gold-Obes.

mixture of carbonate and quartz, banded black-and-white, and comparatively free from eulphides, which envelopes the mass of structureless, workable ore, and is known as coco (potsherds), by reason of its somewhat slaty character. Except for its banded structure, and the presence of a certain amount of graphitic matter, this material shows nothing in microscopic sections to distinguish it from the leaner portions of the Morro Velho ore. Graphite occurs in the Morro Velho lode also, but is there confined to a slicken-sided zone on the contact of the eastern end of the lode with the country-rock. This zone, known as " the slide," has been a constant feature from the surface down to the bottom of the present workings, and recalls a somewhat similar zone, also graphitic, described by Hussak,* in the Passagem mine.

A singular feature, now appearing in one part of the Cuyabd lode, is a considerable mass of a coarse-grained greenish rock of granite texture, composed essentially of plagioclase feldspar, thickly sprinkled with arsenopyrite, and showing irregular fracture-zones, filled with green chlorite. This mass, which carries a little zincblende, occurs in the width of the better ore, with which it appears to have a genetic connection. This also recalls a feature of the Passagem lodcf

Feldspar, in the form of beautiful crystals of albite, is com- mon in the vug-linings at Morro Velho, and is evidently a con- stituent of the gangue as well, though, owing to the fineness of the grain and the absence of observable twinning, it is dis- tinguishable with difficulty from the quartz. A test-sample freed, as far as practicable, from soluble and heavy constitu- ents by means of acids and a heavy solution of such specific gravity as barely to float quartz, gave alumina and soda cor- responding to nearly half of the residue thus purified.

Small proportions of titanium, iron, magnesia, potash and lime, in this analysis, indicate the presence in the ore of other minerals, which, for lack of time, have not been identified. A large water-filled vug was recently struck in the lowest level

ZeiLf. PnH, Oeol., Oct., 1898, p. 345.

t By chance, a specimen is at hand from the Sugar Loaf lode at Goolgardie, W. Anstralia, which resembles this rock in appearance, but is so fine-grained that the character of the feldspar cannot be made out without an analysis. This rock is highly micaceous, and aplitic rather than granitic in texture.

Notbs On Brazilian Gold-Ores. 287

of the Morro Velho mine, under circumstances which indicate that it waa most probably a sealed flask, containing original lode- water. The walls of the vug presented, instead of the usual lining of beautiful crystallizations of carbonates, quartz, sul- phides and albite, a thin earthy coating of gelatinous silica with calcite, and an easily soluble foliated iron silicate (non- tronite?). On dissolving these elements, extremely minute cubes of pyrite and irregular magnetic grains of pyrrhotite were obtained. The water, of which a complete analysis will be presented elsewhere, contains, in the form of silica, carbon- ates and sulphates, a residue of the elements from which this coating was derived, and — with the possible exception of arsenic and gold — all the elements of the lode itself.

This type of ore-body, exemplified by the Morro Velho lode, presents the following characteristics, which must be consid- ered in any discussion regarding its mode of origin :

1. Notable width, combined with a lenticular or stock-like form of the cross-section.

2. Notable constancy in form, mineral composition and bullion-value, throughout a great length of lode.

3. The predominance of carbonates in the gangue and of pyrrhotite among the sulphides.

4. The presence of a feldspar in the gangue.

5. The presence of free carbon, either disseminated through- out the ore or segregated in zones of movement.

6. The aplitic texture of the ore.

7. The presence of confined mine-water, containing in solu- tion all, or nearly all, the chemical elements of the ore-body, and forming by secondary deposition all, or nearly all, of its characteristic minerals.

8. The absence in the ore-body, and in the country-rock im- mediately adjoining it, of well-characterized eruptive rocks, unless the peculiar type of feldspar rock of the Cuyabd lode can be taken as such.

288 Ignbous Rocks As Related To Occurrence Of Ores.

A Consideration of Igneous Rocks and their Segregation or Differentiation as Related to the Occurrence of Ores.

BY J. E. SPURR, CONSTANTINOPLE, TURKEY, f

(New York and Philadelphia Meeting, February and May, 1902.)

Contents.

Pa.Oe

Introduction, 289

L The Reition of Okm-Deposits to Igneous Rocks in General, 290 U. The Distribution of Metals in Sedimentary Rocks, . . 291 in. The Segregation or Differentiation of Igneous Rocks, . 296 IV. The Order of Crystallization of Minerals in Igneous Rocks, 300 V. The Formation of Mineral Segregations in Molten Masses, . 301 VI. The Unknown Finer Laws of Rock-Segregation, . . . 302 VII. The Presence of Metals in the Igneous Rocks, . . . 303 VIIL The Concentration of Commercially-Valuable Minerals by Segregation within Molten Masses, Previous to their Con- solidation, 304

1. Iron, 304

2. Chromiuni, 304

3. Nickd, 305

4. OobaU, 306

5. Platinum, 306

6. Copper, 307

7. Gdd, 308

IX. The Origin of Certain Gold-Quartz Veins, 308

1. Evidence oa to the Origin of Quartz- Veins aa Afagmatic SegregcUionSf . 312

2. The Genetic Connection of Gold-Quartz Veins with Siliceous Igneous Bocks, 316

3. The Subordinate Connection of Gold-Quartz Veins with Basic Igneous Bocks, 321

X. RisuMi: of the Evidence Concerning the Preference of Cer-

tain Metals to Accumulate, by Magmatic Segregation, in Certain Rock-Types of the Established Classification, . 321

1. Basic Bocks, 322

2. Siliceous Bocks, 322

XI. The Relation between Ore-Deposits Due to Magmatic Seg- regation AND Other Ore- Deposits, 323

XII. The Sequence of Volcanic Eruptions, Considered in Connec- tion WITH THE SeQUEICE OF METALLIFEROUS VeINS, . . 325

XIII. The Persistence of Petrographic Provinces, Considered in

Connection with the Persistence of Metalliferous Prov- inces, 328

XIV. Conclusion, 336

Postscript, 338

Published by permission of the Director of the U. S. Geological Survey. t Since returned to the United States, and now again in the service of the U. S. Geological Survey.— R. W. R

igneous rocks as related to occurrence of ores. 289

Introduction.

In a new field like that of the study of ore-deposits, it is hard to keep all sides of the question in sight at once ; to real- ize that the laws worked out for certain types of ore-deposits in one region do not apply to deposits of apparently similar ores the world over. Thus have arisen our most hotly-con- tested controversies, over such questions, for instance, as: Whether bedded ores are mechanical sediments formed at the same time with the enclosing rock, or were introduced later by solution ; Whether metals have been deposited by ascending or by descending waters ; Whether they are derived from the immediate wall-rock, from the rocks of the whole district in which they occur, or from the " barysphere " ; Whether they are deposited in pre-existing cavities or are replacements ; and so on.

The researches of the past score of years or so have rather dampened the heat of these discussions. Investigators have been led to recognize in nature a complexity which permits most of the advocated theories to find their place as factors mutually co-operating to constitute the intricate system which determines the occurrence of ores as we now find them. I think most of us agree with Prof. Van Hise,* that " for many ore-deposits a complete theory must be a descending, lateral-se- creting, ascending, descending, lateral-secreting theory." In- deed, all this — and more !

Van Hise's discussion of the work of underground water in forming ore-deposits seems to me the best general contribution of recent years, not excepting the famous treatise of Posepny. A masterly discussion like this fills, for the moment, the whole mind of the reader, and he might thus fail to consider the im- portance of principles which the author has purposely omitted. Kemp, Lindgren and Vogt, in their discussions of Van Hise's paper, have called attention to certain of these principles, espe- cially those involving the connection of igneous rocks with ore- deposition, or ore-segregation, as I would like to call it.

It is concerning this part of the field that I wish to present some considerations, limited in extent and detail by my lack of

"Some Principles Controlling the Deposition of OreS)" 2Vafw., xzx., p. 173. Omesis of Ore-Depodts, p. 428.

290 Igneous Rocks As Rblatbd To Occurrence Of Ores.

access to a wide range of literature, and by the difficulty of the subject itself. With most of Van Hise's conclusions, I may remark, I fully agree.

For the ideas herein set forth I can claim, of course, only a certain amount of originality. It will be seen that my views (which I have previously announced, although not in such com- pact form as this*) resemble, more or less, those of Lindgrenf and KempJ in this country, and De Launay, Beck and Vogt§ in Europe, but especially the last named.

I. The Relation op. Ore-Deposits to Igneous Rocks in

General.

Two important points have come to be agreed upon by most of the best writers on ore-deposits, namely : (1) That ores in general were originally derived from igneous rocks ; and (2) that present ore-deposits are closely associated with actually-ex- posed eruptives.

Probably at least nineteen out of twenty important ore-de- posits (excepting those of iron) are acknowledged to have a genetic connection with associated rocks of igneous origin. Especially well-marked is the connection of ore-regions or zones with areas or belts of igneous activity. The interdependence of eruptive rocks, hot springs and many ore-deposits has at last attained the dignity of a general law.

The hot springs often owe their heat, and hence their up- ward propulsion, to igneous masses, while the ore-deposits are the direct work of both the other two, the material being largely derived from the rocks and the concentration being effected by the waters. Moreover, the lines of weakness (of

J. E. Spurr, "Economic Greology, Mercur Mining District, Utah," 16M An- nwd BpL XL 8. Oeol. Sun\, Part IL, pp. 395, 449 ( 1895) ; " Geology of the Yukon Gold-District," ISth Annual Rpt. U. S, Oeol. Sw,, Part III., p. 297 (1898); Quartz-Muscovite Rock, from Belmont, Nevada," Am, Jour, of ScLj 4th series, vol. X., Nov., 1900, p. 355.

t Waldemar Lindgren, "Character and Genesis of Certain Con tact- Deposits," 2Van., xxzi., p. 226, and Genesis of Ore-DepositSy p. 716.

t J. F. Kemp, "The Ble of the Igneous Rocks in the Formation of Veins," Trans., xxxi., p. 169, and Genesis of Ore-Deposits, p. 681.

2 J. H. L. Vogt, "Problems in the Geology of Ore-Deposits," Trans,, xxxi., p. 125, and Genesis of Ore-Deposits, p. 636.

II J. F. Kemp, "The R61e of the Igneous Rocks in the Formation of Veins," Trans,, xxxi., 196, 197, and The Genesis of Ore-Deposils, pp. 707-709.

Igneous Rocks As Related To Ogcurrenoe Of Orbs. 291

faulting, etc.) determined by, or at least coextensive with, the intrusion of the molten masses, frequently form the channels of the springs, and thus operate to restrict the ore-deposits to the eruptive zones.

The broad explanation of this association is plainly contained in the proof which we now possess, that the eruptive rocks con- tain in varying amounts the rarer elements (among them, most of the metals), in addition to the common ones.

In the stratified rocks, on the other hand, the metals, though present, seem to be in general less abundant.*

II. The Distribution of Metals in Sedimentary Rocks.

All sediments were probably derived in the beginning from the destruction of igneous rocks, but the elements thus de- rived attain through mechanical and chemical surface agencies a degree of concentration hardly equalled in the igneous rocks themselves. Thus calcium becomes concentrated into lime- stones, and silicon into great volumes of sandstone or quartzite. Among the commercially valuable minerals, salt, gypsum, phosphate of lime, borax and others' have thus become con- centrated. These facts indicate that metals also must be sim- ilarly dissolved out and dispersed. In the case of some of the metals, we know that they are re-deposited in concentrated form. By chemical and mechanical action, iron is concen- trated in bogs, in greensands, and in ferruginous shales and sandstones, there to yield, after some further concentration, such notable deposits as the iron-ores of the Lake Superior region. By chemical action, manganese is concentrated, not only in bogs, but on a large scale in marine sediments, such as shales and limestones, so that most of the commercially im- portant deposits are derived, through the medium of further concentration, from these sources. By mechanical and chemi- cal action such rarer metals and minerals as gold, platinum, diamond, tin-ore, monazite, garnet, etc., are" very highly con- centrated in river channels and in marine shore-deposits. Ex- amples of the enormous efiiciency of surface concentration in producing valuable deposits of the rare metals are furnished

J. F. Kemp, ''The K6le of the Igneous Bocks in the Formation of Veins," IVoiu., xzzi., p. 175, and The Oenesis of Ore-DepoaitSy p. 686.

292 Igneous Bocks As Related To Occurrence Of Ores.

by the world's gold-placers, the Cape Nome beach-sands, and (according to some authorities) the South African auriferous beds. As regards platinum, nearly all the known concentra- tions, so complete as to be commercially valuable, have been effected by surface-agencies.

But, on the one hand, iron and manganese are common ele- ments; and, on the other hand, gold, platinum, tin-stone, etc., are relatively insoluble ; and thus their concentration may be explained. Concerning the metals (such as silver, copper, lead, zinc, arsenic, antimony, etc.), which are at the same time rela- tively rare and relatively soluble, no such satisfactory conclu- sion has been reached. That, upon disintegration of the igneous rocks, these metals largely go into solution in sur- face-waters, there is no doubt. These waters (apart from those which pass underground, where we know that the metals are frequently precipitated in concentrated form*) find their way into lakes, and especially into the oceans. What becomes of the metals which they hold in solution ?

Are they precipitated either in concentrated or in evenly dis- seminated form, or do they remain in solution ? K it be true, as I think it is, that a sedimentary rock, as a rule, contains much smaller proportions of the metals than an igneous rock,t we must conclude that these metals are not evenly precipitated. Yet I find it impossible to believe that all of these metals con- tained in the igneous rocks which have been, ever since the solid world began, going to pieces to form the enormous bulk of known sediments, can have been stored in the sea-water and are there still.

Most of the elements — especially silver, copper, iron, man- ganese, and gold — have been chemically detected in sea-water ; but they are present only in minute traces; whereas the total amount of metals which has passed into the sea in solution during the ages of erosion and deposition must be

C. R Van Hise, "Principles Controlling Deposition of Ores,*' 7}ran8,f xxx., p. 138, et seq.t and The Oenesis of OreDepositSt p. 393.

t J. F. Kemp, "The B61e of the Igneous Bocks in the Formation of Veins," 2Van8., xxxi., 174, says it appears, from analyses of both the sedimentary and the igneous rocks of Missouri for lead and zinc, that the igneous rocks are, as a rule, richer by one place of decimal than the former. F. Posepny, in The QenesU of Ore-Deposits, p. 122, says that innumerable analyses of marine sediments and precipitates, especially of limestones, have failed to show traces of metals.

Igneous Bocks As Related To Occurrence Of Ores. 293

many times in excess of the solvent power of the water at any one time, and vastly in excess of the dissolved amount now contained therein. We must, therefore, confess that, be- sides the metals mechanically laid down in slates and conglom- erates, derived directly from the abrasion of igneous rocks, the same metals have been chemically precipitated somewhere from marine and other surface-waters. Indeed, the researches of Malaguti, Bibra and Forchhammer* long ago established the fact of such precipitation by finding traces of metals in the ashes of marine plants, and in the hard parts of marine ani- mals, such as corals. Among the metals mentioned above as having the question of their concentration at the surface still undecided, lead, zinc, cobalt and nickel have been thus de- tected.

Since, therefore, the metals in question (notably lead, zinc, silver and copper), which are both relatively soluble and rela- tively rare, after being extracted from the igneous rocks during the process of weathering, transportation and sedimentation, have neither been uniformly deposited in the sediments nor accumulated in solution, I am forced to believe that, like the commoner elements (among them the commoner metals) already mentioned, they have been (probably by chemical precipitar tion) deposited in certain places as concentrations y which are, as a rule, relatively richer than the igneous rocks in which the said substances were originally disseminated.

The hypothesis that bedded ores have sometimes been de- posited contemporaneously with the enclosing sediments has been, of late, distinctly out of fashion, and justly so, in te exclusive sense in which it has sometimes been held. Bischof, reasoning from the traces of metals in sea-water, believed that their precipitation as sulphides was possible, and thus ex- plained the occurrences of copper and silver sulphides in the Permian KupferscUefer, and of lead sulphide in the Buntsand- stein.

Groddeck advocated the same idea, and advanced the theory that certain horizons are especially ore-bearing, f Hoefer has applied this explanation to the lead- and zinc-deposits of Upper

♦ CkenL It. Phys, GeoloffU, vol. i., Bonn, 1863, pp. 446-7. C. G. Bischof. t Posepny, Oenesis qf Ore-DeposiUf first edition, p. 112, etc. ; second edition, p. 122.

294 Igneous Rocks As Related To Oocurrenob Of Orbs.

Silesia and other districts, which occur in Triassic marine limestone. In Bohemia and the Urals, as in the German Kupferschiefer district, the Permian rocks contain copper in many places; in Utah and New Mexico (in the Silver Reef and Nacimiento districts, etc.) the Triassic sandstones con- tain copper and sometimes silver; in the Permian of Texas there are three copper-bearing zones, extending over three counties.*

These are examples of numerous deposits which have been described by some able investigators as due to deposition con- temporaneous with the enclosing beds, while, in every case, this conclusion has been repeatedly and vigorously contested. The fact is that in every one of these instances the ore-deposits have an evident genetic connection with fissures, joints, dikes, etc., of later age than the rock; and hence it is argued that the ores (including those disseminated in the rock) have been in- troduced through these fissures.

I need hardly point out that this conclusion is not logically valid. I confess that, after visiting the Mansfeld deposits, I was so impressed by the evident connection of the faults with the ore-bodies, and by the frequent proofs of the formation of min- erals more recent than the country-rock, that I came away quite satisfied that the idea of contemporaneous deposition was old- fashioned and untenable. Yet neither there nor elsewhere does this opinion certainly follow from the observed facts. The present ore-bodies in most of these districts — perhaps in all — are largely secondary concentrations, due to percolating waters, a#d are hence found along water-channels, as held by Posepny and others ; but this does not affect the question whether these waters brought up the metals with them " from below " or con- centrated them from disseminations contemporaneous in depo- sition with the strata. In view of what I have stated above, I am now inclined to hold the latter view.

Among the detrital rocks, slates are known to contain marked quantities of the metals in question. Frick, Forch- hammer and Sandberger found copper, zinc, lead, arsenic, anti- mony, tin and cobalt in clay-slates. These are, very likely, to a large extent, mechanical concentrates from the rocks by the

Kemp, Ore- Deposits of the United StateSy third edition, p. 224, etc.

Igneous Rocks As Related To Occurrence Of Ores. 295

destruction of which the slates originated; yet they are prob- ably also, in some degree, chemical precipitates.

The Mediterranean has been found to contain copper in solu- tion in the proportion of at least 0.01 gramme to the cubic meter. Phillips* says that " the black and usually very sul- phurous matter deposited in basins where searwater has been left to itself constantly contains copper, and the same is gen- erally true with regard to the dark-colored gypseous muds of all ages."

Most chemically precipitated rocksf certainly seem to be much poorer in original metallic contents than the fragmental ones. The limestones of the Mississippi valley have been shown to contain lead and zinc, disseminated in small quantity ; and it is the conclusion of Whitney, Chamberlin, Winslow and others that the ore-deposits have been concentrated from these disseminations. But these limestones appear to contain the metals in smaller quantity than do the older igneous rocks of the region, so that the dissemination in the limestones can hardly be regarded as a concentration. (See footnote, p. 292.)

With these and other facts in mind, we cannot safely give up the idea that metals have been concentrated by surface agencies in favorable places and times, and, consequently, that certain strata (possibly also, and restrictedly, certain geologic periods) are, by reason of their original metallic contents, more favor- able than others to the occurrence of ore-deposits. I would even hesitate equally to deny or to affirm that there is a con- nection between the Triassic and Permian red sandstones and certain copper-deposits. Yet we must be careful not to rush into any such hasty generalization as that of Sir Roderick Murchison, who believed that most auriferous rocks are of Si- lurian age,I — an obsolete idea which I have nevertheless found in one of our latest works on the metallurgy of gold.§

The concentration of metals by surface agencies, though a fascinating study, is out of place in the special inquiry to which this paper is devoted — that of concentration by segregation within molten rocks.

♦ Phillips and Louis, Treatise on Ore-Depontay 1896, p. 132. t This phrase is meant to include limestones of organic origin. X See Kickard's Review," Eng, Min, Jour., Oct 19, 1901, p. 491. i Eisfller, MeiaUurgy of Gold, 1900, p. 31.

296 Iqneous Rocks As Related To Occurrence Of Ores.

ni. — The Segregation or Differentiation of Igneous

Rocks.

Having pointed out the generally-admitted fact that the larger number of ore-deposits have direct genetic connection with ig- neous rocks, I wish to describe one of the chief processes by which the different kinds of igneous rocks originate, which I believe has an important bearing upon the segregation of ores.

While it is known that igneous rocks may be formed directly from the fusion of sediments (in which case their composition is determined by the selective action of surface agencies), yet it is now widely accepted that many, perhaps most, of them owe their peculiarities of composition to a process of segrega- tion which goes on within the molten masses of the earth's in- terior. The evidence for this process, and some of the details of it, have been pretty fully stated by the writer elsewhere,* and only a few points will be mentioned here. The line of argu- ment is best seen if we proceed from examples on a small scale to successively larger ones. Thus, in the laboratory, materials intimately mingled in solution may separate into distinct crys- tals, or into segregated bunches of like crystals ; and in veins the different minerals are often found bunched in the same way. Nearly every igneous rock shows irregularities of composition due to a similar clustering together of like minerals. These aggregations increase from microscopic size to the size of a man's head ; and from these relatively small patches there is a gradation to larger rock-masses, which have marked differ- ences in structure and composition from the rest of the igneous body, of which they, nevertheless, form integral portions. For example, the borders of dikes are freciuently less siliceous, and contain more iron (and associated elements) than the interior of the same bodies. In still larger igneous masses, it is found that different portions have slightly different chemical, miner- alogical and structural characters, while they all grade into one another. Again, it has been observed that in a given district different igneous rocks (such as volcanic rocks erupted at differ- ent times) are often closely related, and pass into one another.

"Geology of the Yukon Gold-District,*' ISth Ann, Rep, U, S. Ged. Surv, Part III., p. 300.

Ignbous Rocks As Related To Occurrence Of Ores. 297

Finally, modern petrographic research and comparison have shown that the rocks of a large region, taken collectively, often present constant differences from those of neighboring regions.

All these phenomena may be explained by the observed fact that in the molten masses, as well as in solutions, there is a force inducing like elements to group themselves together.

Concerning the exact process by which the materials of the molten rocks are enabled to make such important migrations in order to cluster together, there is no certainty; and, indeed, for the purposes of this paper, it is hardly necessary to inquire. Until recently, it was common to appeal to Soret's principle of molecular flow, namely, that molecular concentration may be caused by differences of temperature. Mr. G. P. Becker,* however, has argued against the applicability of this law, on account of the slowness with which it operates. Mr. Beckerf and the writer, independently and at about the same time, called attention to the probable importance of convection cur- rents in producing segregation. By these currents the miner- als which first crystallize (namely, the heavier minerals, such as magnetite, olivine, hornblende, pyroxene, etc.) would be, to a greater or less extent, concentrated in the outer portions of igneous rock-masses, where they are actually often found.

The small segregations in igneous rock are usually either more siliceous or less siliceous (more " acid '' or more " basic ") than the enclosing rock; and extremely acid and extremely basic segregations are often found in close association. This ten- dency of the molten mass to segregate its highly siliceous con- stituents from the rest has also been studied on a large scale, chiefly from the order of succession of lavas erupted at suc- cessive periods in the same district, or of dikes successively introduced. Brogger and Geikie,§ from extensive studies of eruptive rocks in Norway and in Scotland, respectively, both concluded that the rocks progressed from the more basic to the more acid varieties.

"Some Queries On Rock Differentiation/' Am. Jour, Set., Jan., 1897, 4th series, vol. iii., p. 21.

t "Fractional CrystaUization of Rocks," Am, Jour, Sci.y Oct, 1897, p. 267.

J "Geology of the Yukon Gold-District," ISth Ann, Eep, U. S, Oed, Surv,, Part lU., p. 306.

i J. P. Iddings : "The Origin of Igneous Rocks," BulL PhU. Soe, Wa,, Tol. xil., pp. 122, 145, 146.

298 Igneous Rocks As Related To Occurrence Of Ores.

Iddings's* work goes to show the normal law to be that a rock of intermediate composition is followed by rocks progres- sively higher and, at the same time, by others progressively lower in silica, the more basic and the more acid varieties being associated and contemporaneous; so that the series begins with a mean and ends with extremes. This has been considered by the writer to hold good for the dike-rocks of the Forty-Mile district, Alaska,t and (a problem on a much larger scale) for the petrographic province of which the great basin of Nevada forms a portion. J In the case of the Forty- Mile dikes, the most siliceous varieties were found to be later than the most basic ones.

The laws thus deduced agree in this : that a molten rock- mass, under favorable conditions, tends to separate (segregate) into a more acid and a more basic portion ; while the fact that the acid (siliceous) rocks characteristically follow rather than precede the basic (less siliceous) at any one period, joined with the other known principles of segregation, indicates that the change is effected at each stage by the separation and crystalli- zation of the more basic constituents, leaving the more sili- ceous residue unconsolidated.

That the basic minerals in general crystallize first in a cool- ing rock has been proved by microscopic study. If the segre- gation is limited in time, and is broken into by such an occur- rence as eruption and consolidation, the differences attained may be comparatively slight; but under favorable circum- stances extremes may be reached. Thus, rocks consisting almost entirely of olivine, pyroxene, or hornblende, together with iron oxides and sulphides, may originate. On the other hand, rocks made up essentially of quartz and alkali feldspars (ala8kites)§ may be formed, and these may pass by gradual transitions into quartz-veins, as will be dwelt upon later. An illustration of these different results is found in the

Op, cU.

t "Geology of the Yukon Gold-District," ISlh Ann. Bep. U. S, Geol, Starr., Part III., p. 234.

t ''Succession and Relation of Lavas in the Great Basin Kegion,'' Journal of Geology f yoI. viii., p. 621.

2 J. £. : "Classification of Igneous Bocks,'' Am. OedogUtf Apr., 1900, vol. XXV., p. 229.

I6Nb0Us Rocks As Related To Occurrence Of Orbs. 299

dikes of the Forty-Mile region,* which consist of rocks closely related, being made up chiefly of hornblende, quartz and feld- spar. Yet by gradual changes in the proportions of these minerals, rocks of all degrees of basicity and acidity are pro- duced, terminating, on the one hand, in hornblendites (com- posed almost entirely of hornblende) and pyroxenites, contain- ing pyrite, pyrrhotite, ilmenite and other metallic minerals; and, on the other hand, in alaskites, growing gradually more siliceous until they pass, with no break, into quartz-veins.

In the progress of segregation, we have seen that in the acid-gaining portion there is a continuous increase of silica, due to the constant precipitation and removal of the basic por- tions. There is also an attendant increase in the amount of water.

As is shown by microscopic and chemical study, all rocks contain water, but the molten material contains much more than the resulting rock. Most of this water is expelled at the moment of solidification, together with certain gases and a great variety of other materials held in solution.f When rocks cool at the surface, this escaping water forms the clouds of steam, highly charged with gases and minerals, which issue from fissures and other vents ; but when they solidity below the sur&ce the waters and gases are forced into the enclosing rock, producing the recrystallization and rearrangement of its con- stituents, called contact-metamorphism. This is chiefly confined to the contacts of siliceous igneous rocks, being especially re- markable around intrusive masses of granite, where it occu- pies a zone which, in extreme cases, may be several miles in width.

It seems, therefore, that the molten material from which siliceous rocks solidify contains more water than the basic ma- terial. Therefore, we may believe that by the progressive sep- arating out of the more basic constituents the residual portion of a molten mass becomes more aqueous and more siliceous. Thus the peculiar form (often in lenses, not visibly communi- cating with large bodies of igneous rocks) and coarse crystalli- zation of pegmatites are explained ; for these rocks are near the end-product of the siliceous series; and the pegmatitic

"Geology of the Yukon Gold-District," 18t Ann, Bep, U, S. OeoL Surv,, Part III., p. 233. t Danbi Oiohffie ExpimenkUe, Paris, 1879, p. 152.

300 I6Nb0Us Rocks As Related To Occurrence Of Ores.

rocks, by the disappearance of feldspar and mica, grade into pure quartz-veins, which show by their structure that they have been deposited from solutions so attenuated that they may best be described as waters highly heated and charged with mineral matter in solution.

By this process of rock-diflPerentiation concentration is continu- ally effected, through the segregation of like materials. Most of these materials are not commercially valuable. Thus the fre- quent segregation of masses of nearly pure hornblende, pyrox- ene or quartz has no lively interest for the miner. But when (as often happens) such segregations are feldspar or mica, they may acquire economic importance. And if the commonest of rock-constituents may be thus concentrated, other substances may be, also. In the basic Forty-Mile dikes, mentioned above, there was so large a proportion of ilmenite, magnetite, pyrrho- tite and other metallic minerals that small pieces of the rock were drawn by the magnet. A slight further concentration would give commercially valuable masses ; and there is good evidence that, in other districts, many such masses have origi- nated in this way.

IV. The Order of Crystallization of Minerals in Igneous Rocks.

The process of segregation, which we have considered on a large scale, with the progressive precipitation of basic ingre- dients and the leaving behind of the siliceous ores, is recorded on a small scale in the internal structures of igneous rocks, as studied under the microscope.

Under this head I cannot do better than quote Prof. J. F. Kemp,* who says :

Microscopic study of the igneous rocks has shown that, with few exceptions, the rock-making minerals separate from a fused magma on cooling and crystal- lizing in a quite definite order, f Thus the first to form are certain oxides, mag- netite, specular hematite, ilmenite, rarely chromite and picotite, a few silicates, unimportant in this connection (zircon, titanite), and the sulphides, pyrite and pyrrhotite. Next after these metallic oxides, etc , the heavy, dark-colored basic sil- icates, olivine, biotite, augite, and hornblende, are formed. All these minerals are characterized by high percentages of iron, magnesium, calcium and aluminum.

Ore-DepogiU of the United States cmd Canada 4th ed., p. 33. t H. Rosenbusch, " UAer das Wesen der komigen und porphyriBehen Struetur M MoMengesteinen,** Neues Jahrhueh, 1882, ii., 1.

laNEOUS ROCKS AS RELATED TO OCCURRENCE OF ORES. 301

Thej are very generally provided with inclusions of the first set. Following the bisilicates in the order of crystallization come the feldspars, and after these the residnal silica, which remains uncombined| separates as quartz. "

V. The Formation of Mineral Segregations in Molten

Masses.

It has been shown that in the process of segregation in molten masses there is a recognized tendency to split up into more siliceous and less siliceous portions. The basic materials thus concentrated may be the almost exclusive constituents of the resulting rocks. Thus there are not uncommonly rocks made up essentially of the dark, heavy, basic, ferro-magne- sian minerals, biotite, olivine, pyroxene and amphibole, with metallic minerals, such as magnetite, ilmenite, etc., in smaller amounts. The acid materials likewise may form rocks without important admixture of the basic ones, as in quartz alkali- feldspar rocks (alaskite), or in rocks made up almost entirely of alkali-feldspar (sanadinite, albitite, etc.). Further, as already pointed out, the constituent minerals may separate out from the mixture and the like crystals may group themselves together. Thus, there are rocks consisting almost entirely of olivine alone (dunite), of hornblende alone (hornblendite), of pyroxene alone (pyroxenite), of orthoclase feldspar (sanadinite), of sodarfeldspar (anorthosite), and of lime-feldspar (anorthite rock). This completes the roll of the commonest rock con- stituents, save the micas and quartz. Although mica forms small segregations in igneous rocks, the writer is not aware that it occurs as the only essential mineral in any considerable mass of such rock. Quartz also appears at first sight to be an exception ; but the writer will try to show later that this is not so, and that many considerable masses and veins of quartz are the result of segregation from the same molten material that produces other igneous rocks.

Besides these commonest original or primary minerals, there are others which are commonly present in marked quantity in almost every fragment of igneous rock. Perhaps the most important of these is magnetite, which is found in nearly all rocks. Besides this, there are other common metallic min- erals, such as pyrite, ilmenite and pyrrhotite — all iron minerals, Chromite is rarer. Among the non-metallic accessory min- voL. . — 19

302 Igneous Bocks As Belated To Oooubbence Of Obes.

erals, zircon, titanite and apatite are perhaps the most impor- tant. All of these less common minerals (as well as others not mentioned) are known to segregate, to a certain extent at least, so that they are many times more abundant in some rocks than in others.

This being the case, it is natural that the still rarer minerals and elements should also segregate, and should be found in certain rocks in far larger quantity than in others ; and, indeed, this is known to be the fact.

VT. The Unknown Finer Laws of Rock-Segregation.

If there were invariable associations between certain rocks and certain valuable minerals, prospectors and miners would probably have detected it long ago, especially as regards the metals. But in the majority of cases the exceptions, to any rule we may be tempted to construct, are so numerous that we abandon the attempt. That this fact, however, does not contra- dict the conclusions above reached in regard to the preferential segregation of these minerals into certain rocks will appear when we consider how we name and distinguish the rocks themselves. The existing classifications of rocks are all based upon the rel- ative content of the common constituents, the rarer ones being necessarily disregarded. The divisions, granite, syenite, dunite, diabase, basalt, phonolite, and the whole legion of others, are (apart from considerations of structure, age, mode of occur- rence, etc., which have for the moment no bearing on this dis- cussion) founded upon the presence and relative proportions of the ordinary minerals quartz, the various feldspars and felds- pathoids, olivine, mica, amphibole and pyroxene. Even in classifications based upon the chemical composition of the whole rock, the component minerals being lumped together for analysis, only certain ordinary elements are taken into account, and the rock is assigned to its place upon the basis of the rela- tive proportions of silicon, aluminum, iron, calcium, magne- sium, sodium and potassium. Rock-divisions based on these elements do not necessarily connote the presence or absence of any others. For example, a petrographer finding a certain igneous rock, knows at once that this rock is unusually rich in calcium, sodium, aluminum or silicon; but he does not know if it contains more or less than the average quantity of lead.

Ignbous Rocks As Rblatbd To Occurrence Of Orbs. 308

silver or mercury. Each element follows its own independent law of segregation, and disregards the established rock-classifi- cation. Even with the commoner minerals and elements upon which this classification is roughly based, the variations are so wide as to lead the petrographer into grave difficulties. Thus, among the rocks which have been called gabbro we may find some consisting almost entirely of feldspar, and others made up chiefly of pyroxene. One of the commonest chemical divi- sions of the rocks is into acid, basic and intermediate kinds, essentially according to the proportion of silica present; but rocks of different mineralogical composition may have the same acidity. The basic rocks are rich in ferro-magnesian silicates, and so should be exceptionally strong in magnesia ; but occa- sionally cases may be found where gabbro shows less magnesia than granite.

We can hardly expect, therefore, that the identification of a rock-species, under the accepted classification, will be of much help in guiding us to a knowledge of the relative con- tent of the rarer elements. To arrive at such a knowledge, we should have a classification based principally upon the content of these rarer elements, and recognizable in practice by easy physical and chemical marks. But this is clearly impracticable.

In this difficulty, we may be helped to some extent by the prin- ciple which underlies the laws of chemical affinity and the asso- ciation of minerals. Elements and minerals have tendencies to cluster in groups marked by some common characteristics ; each element or mineral prefers to associate with certain elements or minerals rather than with others. This law of selective asso- ciation has long been recognized by the geologist and the chemist. So it seems reasonable that among the rare elements and minerals not considered in rock-classification, some may have such strong preferential association with certain of the commoner rock-constituents on which this classification is based that we may be able to see some connection, even if a rude one, between these rarer constituents and the established rock-types.

vn. Thb of Metals in the Igneous Rocks.

Iron is present — often in high percentage — in nearly every igneous rock. It occurs not only in the dark ferro-magnesian

304 Igneous Oces As Relatbd To Ocgurrencb Of Ores.

silicates, but also as oxides and sulphides, as hematite, magne- tite, ihnenite, pyrite and pyrrhotite.

Chromium, in the form of chromite and picotite, chrome- diopside, etc., occurs in marked quantities as an original con- stituent of many basic igneous rocks. Manganese is present in nearly every igneous rock, as a not unimportant constituent of the ferro-magnesian silicates. The rarer metals, lead, cop- per, zinc, tin, antimony, arsenic, nickel, cobalt, silver, gold, and the still rarer ones, have all been repeatedly found in fresh igneous rocks, particularly in the dark bisilicates.

Vm. The Concentration of Commercially-Valuable Min- erals BY Segregation within Molten Masses, Previous TO THEIR Consolidation.

1. Iron. The fact that iron is unequally distributed in igneous rocks is well known. Many highly siliceous rocks (acid granites, alaskites, etc.) have only a trifling quantity (often 1 per cent, or less), while the basic rocks may contain 10, 15, and even 20 per cent, of iron oxide. Of this iron, a part is generally in the form of magnetite, a mineral shown by the microscope to be thickly disseminated in many basic rocks. It is generally titaniferous, and grades into ilmenite. From the highly mag- netiferous phases of ordinary basic rocks to a phase where the magnetite becomes the principal constituent is an easy step. Such are the occurrences at Cumberland, Rhode Island, at Taberg, in Sweden, and in many other places. At some of these localities the iron mineral may gradually increase so as to almost exclude the other constituents, as at Taberg; or it may quite do so, as in the anorthosites of Minnesota and else- where, forming masses of iron-ore. As to the origin of these ores by segregation within the molten masses previous to cool- ing, there is a practical unanimity of opinion.

2. Chromium. Like iron, chromium has a very manifest uneven distribution in igneous rocks, being rare in the siliceous ones, while in many of the basic ones it forms a not insignificant constituent, espe- cially in rocks containing olivine.* In these rocks its relations

Zirkel, Lehrbuch der Petrographie, 2d ed., voL i., p. 426.

Igneous R0Ck8 As Belated To Occurrence Of Ores. 305

to other minerals show that, like magnetite, it is one of the earli- est to crystallize during consolidation. That the chromite may, in some portions of these rocks, become so abundant as to form the principal constituent, the rock being nevertheless in nearly the state in which it cooled from fusion, is an occurrence which we might expect from our knowledge of the selective segregation of other constituents, and one which has been repeatedly ob- served. Vogt* has described a fresh peridotite from Norway which was almost or quite rich enough in chromite to be worthy of exploitation. The most important occurrences of chrome- ore occur in serpentines, which can generally be shown to be the product of decomposition of basic igneous rocks, chiefly peridotites (olivine rocks) ; and these deposits are considered by Vogt to be the result of segregation while the mass was molten (magmatic segregation), although they had been ex- plained by others as due to after-actions which took place dur- ing the alteration of the fresh rock to serpentine, or even to pneumatolytic (vaporous) action at the time of the rock's con- solidation. J. H. Pratt, after studying the chrome-ores of North Carolina, arrived at the same conclusion as Vogt for other regions, namely, that the ores were actually magmatic segregations. Kempt favors the same origin for .other chromite- deposits in the United States. The writer, after examining the chromite-deposits near Saloniki, Turkey (Macedonia), and also in Asia Minor, inclines to the belief that most of these deposits have originated as magmatic segregations from the enclosing peridotitic rock.

3. Nickel

Nickel occurs as an original constituent of some olivinesj in basic igneous rocks. It is also found in more considerable amount in pyrrhotite, a sulphide of iron which is frequently a primary mineral in igneous rocks and one of the first to crys- tallize on consolidation. Nickel occurs also as an alloy with native iron, in meteorites and in basalt.

In certain igneous rocks — as, for example, in the peridotites of Douglas county, Oregon, and of Webster, North Carolina — nickel is much more abundant than in others of the same petro-

Quoted by J. F. Kemp, Ore-Deponts of the U. S. and Canada, 4tb ed., p. 413. t Op. eU.j p. 415. Dana, System of Mineralogy, 6th ed., p. 453.

306 Igneous Rocks As Related To Occurrence Of Ores.

graphical character. In the instances named, the nickel, upon the weathering of the rock, separated out as nickel silicate, and became concentrated sufficiently to be of possible economic im- portance.

Although these ore-deposits are immediately due to circulat- ing surface-waters, which have accomplished a second concen- tration, the first and most important concentration was that which brought together unusual quantities of nickel in these particular rocks, and this was plainly done by magmatic segre- gation.

It has already been noted that pyrrhotite, like the other early crystallizing metallic minerals, may become abundant as a primary constituent of igneous rocks — as, for example, in the case of the Forty-Mile creek dike, already mentioned.* Cases where niccoliferous pyrrhotite in basic igneous rocks, evidently a primary constituent, gradually increases so as to form com- pact masses and to become a valuable ore, have been described on the best authority.

Of such origin (partly, at least) seem to be the niccoliferous pyrrhotites of Sudbury, Ontario, and those of the Gap mine, Lancaster, Pennsylvania, f

4. Cobalt

This metal has the closest associations with nickel, and the general conclusions arrived at for the one are probably to a considerable degree good for the other. Like nickel, cobalt is present in perceptible quantity in certain basic igneous rocks, where it has been identified as occurring in olivine, and, al- loyed with native iron, nickel and copper, in Greenland basalt.

As yet, however, we have not sufficient reliable data to de- termine whether any important cobaltores are formed princi- pally by magmatic segregation.

5. Platinum.

Platinum, in perhaps the majority of cases, is found closely associated with chromite or nickel, or both. Like these min- erals, it is almost invariably genetically connected with basic

See p. 300.

t J. F. Kemp, Ore- Deposits of the United StcUea and Canada, 4th ed., p. 431.

X Dana, System of Mineralogy 6th ed., p. 453.

Igneous Books As Relatbd To Oocubrenge Of Ores. 307

olivine rocks, or with the serpentine-rocks arising from the alteration of these. As an original constituent in basic igne- ous rocks, it is said to have been found by both Daubree and Engelhardt. More recently, native platinum has been discov- ered in igneous rocks in the Urals, in the Nizhni-Tagil district, and the Goroblagodat district These are extremely basic peri- dotitic rocks, containing large amounts of magnetite and chro- mite, besides platinum. According to Inostranzeff, the plati- num occurs as grains and leaves in the chromite. In the Goroblagodat district, while the peridotites contain by far the larger amount of platinum, Saytzeff found the metal as an original constituent in other igneous rocks also, such as porphy- rite, gabbro-diorite, and syenite-gneiss. Mr. C. W. Purington also obtained, on crushing and panning the peridotite of this district, many fine colors of platinum.* The writer has also had the privilege of visiting the district, and of collecting some of the platinum-bearing peridotite.

The Ural occurrence, both by reason of the presence of the platinum disseminated in basic igneous rocks and its connec- tion with chromite and magnetite of acknowledged igneous origin, must be admitted to be a product of magmatic segrega- tion ; and how powerful this segregation has been we learn from the fact that assays of the ferrous blebs (the most basic segregations) in the Nizhni-Tagil rocks gave a figure corre- sponding to $50 per ton.f

That in this region the platinum has been remarkably con- centrated, as compared with similar rocks in other places, is shown by the observation of Saytzeff that even rocks elsewhere not known to be platiniferous — " porphyrite, gabbro-diorite and syenite-gneiss" — contain it. J

6. Copper. Copper, as an original constituent, is known to enter into the composition of the dark ferro-magnesian silicates of the igneous rocks. It occurs also in meteorites, and, alloyed with

C. W. Purington, "Platinum Deposits of the Tura River-System," Trans., xxix., p. 8. t Purington, op. ci&, p. 8.

X A note in the Etig. and Min. Jour,, November 16, 1901, p. 632, says that samples of rock from the State of Washington contain, according to Prof. J. F. Kemp, from 0.375 to 0.5 oz. of platinum per ton. The nature of the rock is not stated.

308 Igneous Books As Rblatbd To Ogourrbnob Of Orbs.

native iron, in the Ovifak (Greenland) basalt The segrega- tions of pyrrhotite before noted in connection with nickel, and believed to have formed in the distinctly ante-consolidation period, are frequently cupriferous, and even contain copper pyrites, as at Sudbury, Ontario. The magmatic segregation ot the pyrrhotite being granted, the copper also has probably been chiefly concentrated in the same way.*

According to some observers, even high-grade copper-ores in various districts have had. this origin, f

7. Gold.

Pyrrhotite frequently, and chalcopyrite generally, contains gold. Some masses of auriferous pyrrhotite and chalcopyrite have been thought to have originated like the niccoliferous pyrrhotite above mentioned. Such is the case at Rossland, B. C, where the ores have been considered by many writers to be magmatic segregations, while other observers, equally reliable, believe them to be secondary replacement deposits or fissure- veins. The hypothesis of a first concentration by magmatic segregation and a second by circulating waters may possibly be the key to the problem.

Native gold, probably as an original constituent, has been found in granite,J in eurite§ (alaskite), in quartz-trachyte, and in gabbro.lf

IX. Thb Origin op Certain Gold-Quartz Veins.

As remarked in the preceding paragraph, native gold has been found in both basic and acid rocks. It has also been de- tected in the dark ferro-magnesian silicates of rocks of all de- grees of acidity. The commercially- valuable concentrations of gold are generally connected, now with basalt or gabbro, now with diorite, now with phonolite, rhyolite, or granite. They occur also in many different forms, as replacement-de-

J. F. Kemp, OreDeposUs of the U, S. and CanadOy 4th ed., pp. 436-7. t Vogt, Problems in the Geology of Ore-Depoaite," IVaTw., zxzi., p. 131. Cfen- eU of Ore-DepontSf p. 642.

X G. P. Merrill, Am, Jour. Sci, April, 1896, 4th series, vol. i., p. 309.

G. W. Card, Records OeoL Surveys of N. S, TT., 1895, p. 164.

II W. Moricke, Tsehermak, Min. MiUh., zii., p. 195.

Cited by J. F. Kemp, Ore-DeposiU of the United Stoics and Canada, 4th ed., p. 36.

Igneous Rocks As Related To Oggurrbngb Of Ores. 309

posits in limestone; as disseminations in igneous and sedi- mentary rocks ; as contact-deposits near intrusive masses ; and in fissure-veins. Most of the known processes by which ore- deposits are found have probably been active in producing gold- ores. A possible case of origin by segregation in a basic magma has judt been noted (at Rossland). But the writer believes that most frequently the metal is concentrated in siliceous magmas.

After studying the Yukon gold-quartz veins in 1896-7, the writer announced a theory of their formation as the end- product of rock-segregation in the region where they occur.* In this connection a brief outline of the theory will be given, with a few additional observations, since made, which tend to strengthen it.

Under a previous heading, in considering the segregation (differentiation) of igneous rocks, the conclusion has been reached that many magmas segregate by a repeated concentra- tion and consolidation of the basic constituents, leaving a more siliceous residue.

Just as this process may result in rocks of extreme basicity, such as olivine, hornblende and augite rocks, and even in seg- regated masses of the metallic minerals which ordinarily are accessory constituents, so, at the other end of the series, very siliceous rocks arise. From the siliceous granites the transi- tion is gradual (and may often be observed in a single rock- mass) to more siliceous rocks, consisting almost entirely of quartz and alkali-feldspar without important admixture of the dark ferro-magnesian minerals.

These rocks are regarded by the writer as far more wide- spread and important than has generally been recognized, and to the group he has applied the general term "alaskite.f These alaskites may pass gradually into quartz- veins.

In the multitudinous and varied dike-rocks of Forty-Mile creek, Alaska, where most of the observations were made which led up to the theory in question, every stage in the in- creasing acidity was observed. J The rocks which here occur

J. E. Sporr, "Geology of the Yukon Gold-District," 18 Ann, RepU U. & QtoL Surv., III., p. 312.

t J. £. Spurr, ''Classification of Igneous Kocks," Am. Geologist, April, 1900, p. 229.

t J. R Spurr, "Geology of the Yukon Gold-District," \%th Ann, Eepi. U. S. Geol. Survey, Part III., p. 282.

310 Igneous Rocks As Related To Occurrence Of Ores.

in greatest bulk are hornblende granites and hornblende dio- rites, both of medium acidity. From these rocks the change is very gradual to the extremely basic rocks before mentioned. We will, however, not dwell on this phase of the segregation, but turn to the development of the siliceous rocks, which is equally well displayed.

The basic hornblende granite, which forms the greatest rock masses, contains subordinate quantities of biotite. By a very gradual transition the hornblende diminishes in amount as the proportion of biotite increases, so that the rock becomes a biotite-granite ; and in many dikes the amount of biotite be- comes less and less, giving rise to an extremely siliceous granite, in which the biotite is an insignificant constituent as compared with the quartz and feldspar. With further diminu- tion of the biotite the granites change into essentially quartz- alkali feldspar rocks — alaskites. These rocks are sometimes fine-grained, or may be coarse, like granites, but have a nearly uniform structure and composition. In the alaskite series the change is continued by a relative increase in amount of quartz and decrease of feldspar. One remarkable phase studied is a porphyritic dike rock whose ground-mass consists almost entirely of quartz in small interlocking grains, giving, both in the hand-specimen and under the microscope, the exact appear- ance of a quartzite. Yet this rock contains scattered but regu- larly distributed porphyritic crystals of feldspar. It is thus not only related by the closest ties to similar slightly less sili- ceous alaskites of the same district, but it is only removed by its scattered porphyritic crystals from being a typical quartz- vein. Moreover, the superabundant quartz in these very sili- ceous dikes tends to segregate into bunches, which may become large, and which have all the characteristics of ordinary vein- quartz. With the progressive increase in silicification the quartz begins to occupy an important portion, and finally the larger portion, of the dike. The feldspar becomes restricted to certain places, sometimes occurring irregularly, sometimes collecting near the walls, while the quartz lies in the center.*

This distribution is in accordance with the theory of segregation by the aid of convection currents Yukon Gold-District," \SthAnn, Rep. U. S, Oeol. Surv.y Part III. , p. 306 ), by which the least siliceous and first-precipitated minerals are concentrated near the cooler dike-walls.

Iqnbous Rocks As Belated To Occurrence Of Ores. 311

Finally, by the disappearance of the feldspar, the dike becomes an ordinary quartz-vein.

In one and the same dike the change from a coarse alaskite to a typical quartz-vein may be seen in all its stages.

The quartz-veins generally contain pyrites, as do all the other dikes of the region ; they contain occasional biotite, and some segregated calcite, as do also the coarse alaskites. It may be remarked, in connection with the calcite, that epidote, the silicate of lime, aluminum and iron, is a constant and impor- tant mineral in all the rocks of the Forty-Mile region, from the homblendites and pyroxenites to the most siliceous alaskites.

These veins contain pyrite, argentiferous galena, and free gold. From them a portion of the Yukon placer-gold is probably derived, much of the remainder coming from older quartz- veins which, by reason of the shearing and metamorphosis they have undergone, do not offer plain evidence as to their origin.

Therefore it has been concluded that certain quartz-veins in the Yukon district (part, at least, of which are auriferous) have originated by a process of magmatic segregation, which has separated them from other materials while in a state of aqueo-igneous fusion (the condition of molten rock in general), and that they represent the siliceous extreme of that process. From this standpoint, they are a variety of the igneous rocks. But it has been shown that as magmas become more siliceous they also contain more water ; so, when the stage of quartz- veins is reached, the magma is believed to be so attenuated that it may best be described as water highly heated and heavily charged with mineral matter in solution. There would thus be no great difference (save in their associations, and very likely in the selection of the mineral matters which they con- tain) between these solutions and others where the water may have had, say, an atmospheric origin ; and a quartz- vein origi- nating by magmatic segregation might often not be distinguish- able from one formed in the many other ways which are possi- ble. The main point of interest, so far as this discussion is concerned, is, as the writer believes, that veins originating by magmatic segregation are especially apt to contain gold (with- out the admixture of so great proportions of the commoner metals as is usual in ore-deposits), and that thus an important class of typical gold-quartz veins has been formed.

312 Igneous Rocks As Related To Occurrence Of Ores.

Having briefly stated the evidence and formulated the theory for the Yukon district, let us recite some of the evidence bear- ing on it elsewhere.

1. Emdence as to the Origin of Quartz- Veins Magmatie Segregations.

Pegmatites are coarsely crystalline rocks which show close relationships with ordinary igneous rocks, such as granites, on the one hand, and with veins such as are known to be due to precipitation from aqueous solution, on the other. Hence there has been much perplexity and contention, some referring them to the " igneous " rocks and calling them dikes others in- sisting that they were "aqueous" and true veins. But the latest and best essays on the subject* agree that pegmatites are formed under conditions intermediate between those which govern the formation of siliceous " igneous " rocks like granite, and those under which quartz-veins are formed. There is, in short, no line of demarcation in nature, corresponding to our artificial and arbitrary one, between igneous rocks and certain aqueous veins — between granites and certain large masses of quartz.

Transitions of pegmatite- to quartz-veins, showing absolute and uniform gradation from one to the other, have been noted by Crosby and Fuller, Williamsf and Van Hise, J and transitions or evident close and constant relations between pegmatites and granites have been noted by Crosby, Brogger, Van Hise and Williams.

Professor C. W. Hall§ has furnished notes on Eastern and Central Minnesota, where, in connection with intrusions ot hornblende-biotite granite, are shown " granitic veins." These are " locally pegmatitic, with coarse and well-developed feld- spar individuals imbedded in a matrix of hornblende and bio- tite, while elsewhere they are finely textured, possess a reddish

"Origin of Pegmatite/' by W. O. Crosby and M. L. Fuller, Amer. Oeoloffist, vol. xix. (1897), p. 147; Die Mineralien der Syenit-pegmatitgdnge der sSdnorwe- gischm Augit- und Nephdin-syenUe,*' by W. C. Brogger, Zeitaeh, JurKrysL, vol. xvi., 1890, pp. 215-236. " Origin of the Maryland Pegmatites," by G. H. Williams, Ibih Ann, Report U. S. Oeol, Sur., 1896, p. 675. f OpciLfp. 679.

t IM Ann. Report U. S, Ged. Sur,, Part I., 1896, p. 688.

i Keewatin Area of Eastern and Central Minnesota, Bull, OeoL Soc Amer.f vol. xii., pp. 367-8-9 (1901).

Igneous Books As Rblatbd To Occtjrrbnce Of Ores. 313

color, and are highly siliceous in composition." Associated with these are veins of quartz. In the St. Louis river-district the veins, when wide, become pegmatitic. The veins some- times carry segregated sulphides and siderite. One, on Kettle river, has been explored for gold.

Professor J. F. Kemp* observes that on the north shore of Long Island Sound " pegmatites are abundantly developed in connection with granites, and all grades are shown up to prac- tically pure quartz." One of the largest quartz-veins, which Professor Kemp thinks belongs to the pegmatitic series, car- ries, in portions, ferruginous minerals and traces of gold.

Dr, E. Hussakf has described an auriferous quartz-vein in Brazil which he regards as an ultra-acid granitic dike. Mr. Waldemar Lindgren, however, dissents from this conclusion. J

According to Phillips and Louis, § at Timbarra, in New South Wales, " gold is found in granite ; these gold-fields consist of a granitic tableland, traversed by dikes of eurite|| and pegma- tite, also occasionally showing veins of auriferous quartz, which may possibly be segregation deposits."

At Silver Peak, Nevada, the writer noticed transitions from the granitic rock (which is there intrusive in Cambrian lime- stones) into quartz-veins. Mr. H. W". Turner, who studied this region more in detail, made the same observation independ- ently, and communicated it subsequently to the writer. Accord- ing to him, these segregated veins seem to be connected in some way with the Silver Peak ore-deposits, which are gold- quartz veins.

On the Mojave river, in Southern California, the writer ob- served one of the most rapid and complete transitions from quartz-veins into granite which he has ever seen. Here Pale- ozoic limestones and quartzites (considerably metamorphosed) are cut by intrusive granite, whose dikes grade into pegmatite, and these to quartz-veins. In a single dike he observed, within the length of not many yards, a complete transition from a

♦ " The Rfile of the Igneous Rocks in the Formation of Veins," Trans.f xxxi., p. 182. Oenegis of Ore-DepodiSj p. 693.

t ZeiUchr Jur prakt, Oeoloffie, 1898, p. 345.

X ''Metasomatic Processes in Fissure- Veins," Ih-ans.f xzz., 642, and Genesis of Ore-DepogiUj p. 562.

i Ore-DepositBy second edition p. 649. Alaskite. — J. R S.

314 Igneous Rocks As Rblated To Occurrence Of Ores.

fine-grained pegmatite to a typical quartz-vein. Gold is found in this locality (Oro Grande), but, unfortunately, he did not remain long enough to find whether it is in these quartz- veins.

The writer has also studied the transition of granite and alaskite through pegmatitic stages to quartz-veins, in the Walker river range, in northwestern Nevada, near the Indian reservation ; and again in the Mojave desert, southeast of Ran- deburg, California.

At Belmont, in Nevada, the writer has made a brief study of an interesting dike-rock and its associated phenomena.* The dike is one of the outlying offshoots from a large body of sili- ceous granite ; it is nearly half a mile wide, and cuts Silurian slates and limestones. Near the contact the slates and lime- stones have been transformed into jasperoidf by the introduc- tion of silica ; in part they have also been altered to micaceous schists, often containing disseminated small bundles of yellow and red metallic oxides. In this rock occur quartz-veins which carry rich antimonial silver-ores.

The dike-rock varies greatly in texture and composition. One specimen collected, classed as a siliceous muscovite-biotite granite, is remarkable for the irregular arrangement of its con- stituent minerals, the quartz often segregating into bunches a quarter of an inch in diameter, with all the characteristics ot vein-quartz. A coarser-grained biotite granite at some little distance has the same peculiarity, and in this place the blotches of quartz, mosaics of intergrown grains, are from one-third of an inch to one-half an inch in diameter. But the rock of chief interest is one which looks like a micaceous quartzite, and, indeed, consists essentially of muscovite and quartz. Micro- scopic study reveals it in the presence of the feldspar albite, and proves that the muscovite has largely been derived from the alteration of orthoclase. Yet the rock is fresh and hard, and th change has not been affected by surface weathering.

The process must be regarded as one of endomorphism, and as connected and probably contemporaneous with the exomorphism indicated by the alteration of the siliceous limestone of the wall-rocks to jasperoid and mica schist

J. E. Spurr, Am. J, Sci, 4th series, vol. x., p. 351 (1900) : Quarts-Mus- covite Bock from Belmont, Nev., the Equivalent of the Eussian Beresite." t J. E. Spurr, "Geology of Aspen District," Mon. xxxi., U. S. O. &, p. 219.

Igneous Rocks As Related To Occurrence Of Ores. 815

''In both the intrusive and the intraded rock the result of the metamorphism has been the same, producing quartz and muscovite at the expense of the ortho- clase on the one hand, and of the calcite and subordinate minerals on the other. In the case of the wall-rock the metamorphism, being apparently, from its dis- tribution, dependent upon the intrusion, evidently took place after this intrusion, and was brought about by the solutions which accompanied the igneous rock, or were residual from its solidification. Within the dike the similar alteration was probably contemporaneous vrith that in the country-rock."*

White quartz-veins, often several feet in width, occur in the immediate vicinity of this intrusive mass. For these the con- clusion is reached that :

These quartz- veins are probably contemporaneous with those already de- scribed as occurring in irregular form within the dike-rock itself, and as evi- dently representing the final product of the residual solution of the general magma. In these quartz-veinsf the metallic minerals [chiefly stetefeldtite, an argentiferous ore of antimony, with some lead, copper and iron] are scattered in bunches or disseminated particles, rarely in banded form

"The metallic minerals being, from their habit, plainly contemporaneous with the quartz- veins which enclose them, it is evident that the deposition of these minerals, the formation of the quartz-veins, the metamorphism of the country- rock to jasperoid and muscovite schist, and the endomorphism of the muscovite- granite to quartz-muscovite rock were contemporaneous occurrences, all brought about by the same agencies, which were the solutions representing the end- product of the differentiation of the granitic intrusive rock.''

This Belmont quartz-muscovite rock acquires additional in- terest as the equivalent of the so-called beresite of the Urals, which the writer has had the privilege of studying in the field. After considerable investigation and discussion, the Ural beres- ite (composed of quartz and muscovite) has been shown by Arzruni to be an alteration from a muscovite-granite in the same way as the Belmont rock. The analogy between the Bel- mont phenomena and those of Berezovsk is still more striking when we consider the close connection of the beresite with gold-quartz veins. This rock forms intrusive dikes from 2 to 40 meters wide, cutting schists. Previous to all scientific in- vestigation, these dikes were recognized by the miners as the surest guides to gold. The auriferous veins are found in the dikes, and only rarely extend into the country-rock. They gen- erally stretch across the dikes at right angles to the walls, and have been considered as filling " fissures of contraction " by

Op. eitf p. 366.

t According to 8. F. Emmons, "Geol. Expl. of 40th Parallel," vol. iii. (Mining Industry), p. 398.

316 Igneous Books As Related To Ocourrenge Of Orbs.

Posepny.* This is probably correct, for the veins follow the same lines as the " columnar jointing " of dikes, which are due to contraction.

At Belmont the important point in determining the age of the quartz-veins is their contemporaneity with the contact- metamorphosis of the wall-rocks, which fixes their period of formation as during the final stage of the consolidation of the granite. We have not suflicient data to announce this same criterion for Berezovsk, and in the study of ore-deposits one must ever beware of reasoning too closely from analogy ; but the fact that the " beresite " has, like the Belmont quartz-mus- covite rock, originated not by surface alteration, but through deeper-seated solutions,t that this alteration seems a part of that which produced the gold-quartz veins,J and that the latter are confined to the dikes or their immediate vicinity, — all these are in favor of the hypothesis of the origin of the veins as the last and most siliceous and most fluid segregation product of the granitic magma.

2. The Genetic Connection of Oold-Quartz Veins with Siliceous Igneous Rocks.

We have reviewed a number of cases of the actually ob- served transition from siliceous igneous rocks to quartz-veins, with or without a pegmatite stage, and in most of these the veins contain disseminated metals, notably gold. When mining engineers and geologists begin to look more carefully for such transitions, it is probable that numerous others will be found; Meantime, the number of instances in which gold-quartz veins are intimately associated with siliceous intrusive rocks is really remarkable.

On the Pelly river, in British Columbia (a part of the Yukon gold-belt). Dr. G. M. Dawson § found evidence to show that the development of quartz-veins had occurred contemporaneously with the upheaval of the granites, and probably by some action superinduced by the granite masses themselves while still in a formative condition.

Oenesis of Ore-Deposits first edition, p. 70 ; second edition, p. 76. t The beresite is deeply decomposed by surface agencies, but this is inde- pendent of the agency by which the first rock originated.

X The beresite itself contains gold in small quantity (50 drachms to the ton). Amu Rep. GeoL Nat HiaL Survey Canada, yol. iii., Part I., p. 35 B.

Ignbous Rocks As Related To Occurrence Of Ores. 317

In the Cook Inlet region, Alaska, gold is found in aplite* dikes, according to Mr. W. C. Mendenhall. In the Nome re- on, Messrs. Schrader and Brooksf report veins containing sul- phides, quartz and calcite, catting metamorphic marble and schists. A large area of granite is also reported.

In the Slocan District, British Columbia, according to W. A. Carlyle,J the typical gold-quartz veins, as well as quartz-veins carrying argentite, native silver and gold, appears to be con- fined to granite, while veins containing argentiferous galena, blende, siderite, tetrahedrite, etc., are found both in stratified rocks and granites. In California, Whitney§ noted that, while the granite itself is not metalliferous, its appearance seems to be closely associated with the metamorphism of the adjacent sedimentary rocks, while this latter condition is, as a general rule, the concomitant of the occurrence of minerals or metal- liferous veins. Prof. J. F. Kemp|| remarks : " The enormous introduction of silica is one of the most extraordinary features of the geology of the Sierras, and indicates a remarkable ac- tivity of circulating waters. The igneous intrusions doubtless promoted, if they did not cause, the circulations." In the Lake of the Woods district, schists, early granite, and gneiss are cut by later granite. The veins are found in the schists, but favor the portions near the contact with the granite or gneiss.

In the gold-bearing region of Nova Scotia, metamorphosed sedimentary rocks containing quartz-veins are cut by many eat intrusions of granite.**

In Madison county, Montana, gold-quartz veins occur in granite ; in Beaverhead county, at the contact between lime- stone and granite; in Lewis and Clarke county, in granite and slates, etc. ft

In Rhode Island, quartz-veins are frequent around the great inclusions of granite. Traces of gold have been met. J J

♦ "Aljwkite."— J. E. a t Trans,, xxx., p. 238.

t Quoted by J. F. Kemp, Ore-Deponts of the United States and Canada 4th ed., p. 395.

The Aunfenmi OraveU of the Sierra Nevada, p. 363. II Ore-Depoaits of the United States and Canada, 4th ed., p. 370. f Kemp, op. ci(., p. 386. Kemp, op. cit., p. 397.

ft Kemp, op. eiL, p. 320. Jt Kemp, op. cit, p. 383.

vol* xxxni.— 20

818 Igneous Rocks As Related To Occurrence Of Ores.

In the Appalachian gold-quartz region are numerous intru- sions of granitic rocks, and pegmatite is abundant.*

In British Guiana, gold-quartz veins " occur mostly in meta- morphic schists and gneiss; and nearly all the streams and rivers that traverse regions occupied by the above rocks, or by granite, are gold-bearing."t

In the Sutherland gold-fields in Scotland, the rocks are gran- ites, gneiss, mica-schist, and quartzite, and, in a few localities only, quartz-veins. On the stream called the Kildonan, " the miners preferred working either in the vicinity of masses of granite, or in the neighborhood of a partially decomposed greenish schist"

No gold has been found in situ in this district, but the drift is entirely composed of fragments of purely local rocks, while quartz pebbles are almost entirely wanting.

Influenced by these and similar considerations, Messrs. Joass and Cameron are disposed to ascribe a granitic origin to the gold of this area. I

On the island of Bommel, in Norway, the chief country- rock is " gabbro," in which large dikes of " quartz-porphyry," passing into granite, and of altered diorite, occur ; on the south of the district is a large tract of slate, in which are non-aurif- erous quartz-veins. The " quartz-porphyry " dikes, and those of diorite, contain strong gold-quartz veins, whose general contemporaneity with the period of igneous intrusion is shown by their being older than some dikes and younger than others. §

In the Kotchkar district, in the Urals, the gold-quartz veina as seen by the writer on the occasion of a brief visit, are imme- diately the results of circulating waters subsequent to the con- solidation of the country-rock ; but they occur in and are prob- ably primarily dependent upon the granite. There are analo- gies in many ways between this district and that of Monte Cristo, Washington State, TT. S. A., where, according to the writer's study, the ore-deposits (chiefly replacements of igneous rocks by auriferous sulphides), while immediately the work of ordinary circulating waters, yet are closely dependent upon

Phillips and Loais, Ore-DepoeitSy 2d ed., pp. 786-7. t Phillipe and Louis, op, ciL, pp. 887, 888. t PhillipB and Louis, op. ciL p. 320. i Phillips and Louis, op. cU., p. 519.

Igneous Rocks As Related To Occurrence Of Orbs. 819

great intrusive bodies of tonalite in which thejirsi concentration has probably been effected by magmatic segregation.

In India, it has been stated by Mr. King that the so-called quartz-reefs of the Travancore State " are not really veins, but merely the outcrops of beds of quartzite, associated with feld- spar, which run with the foliations of the gneiss. Although minute traces of gold may sometimes be detected in these rocks by assay, the amount present is far too small to render them of any commercial value as a source of that metal." The phrase "beds of quartzite, associated with feldspar," strongly suggests fine-grained siliceous alaskite dikes. In the Wynaad district, " the gold-bearing area consists of granite, gneiss, and various metamorphic rocks, traversed by veins of quartz, which, with their branches, are auriferous."*

In China, the reported gold-quartz veins occur almost en- tirely in granite, as at Ninghai, the Chao-Yuen district, and Yeshui in Mongolia, f

In Siberia, the connection of the gold with granite and gran- ititej has been observed in more than one place. §

Turning to Australia, we find a relation of the gold to silice- ous igneous rocks quite as striking as in California and Alaska. In Victoria,

"GK)ld is not only found in veins traversing granite, felsite and diorite, but is also sometimes disseminated throughout the rocks themselves.

I quote from Phillips and Louis :Tf

"In a paper read before the Geological Societyof London in April, 1872, Mr. Richard Daintree drew attention to the fact thMt the auriferous Devonian districts of Queensland are entirely confined to such as are penetrated by certain eruptive rocks, principally pyritous diorites. In these diorites, and near the point of their intersection with the Devonian strata, veins of quartz, calc-spar and iron-pyrites had been examined and found rich in gold, while the extensions of such veins at any considerable distance from the intrusive rocks were found to be barren. In- stances were also adduced to show that the pyrites sporadically distributed through the diorites was occasionally distinctly auriferous, and had, by its decom- position and disintegration, produced drifts containing gold in paying quantities.

"In a subsequent communication, Mr. Daintree states that since the date of

Phillips and Louis, Ore-Deposits, pp. 662-3.

t Phillips and Louis, op. ciL, p. 618. t Ahiskite."— J. R a

2 Quoted by DeLaunay, GoBtribntion k Ttude des Gites MdtaUifdres,'' AnnaUs d. Ifmes, August, 1897, 9tb series, vol xii., p. 224.

t Phillips and Ixmia, Ore- Deposits, p. 620. Op cit,, p. 641-2.

320 Igneous Rocks As Related To Oogurrencb Of Ores.

his first paper he had leaned from Mr. C. Wilkinson, then Government Geolo- gist of New South Wales, that the same facts hold good for the New South Wales gold-fields lying in Upper Silurian or Devonian areas ; and Mr. G. H. F. Ulrich, the Curator of the Technological Museum in Melbourne, in his catalogue of the rocks in that institution, gives details which go to show that the Upper Silurian rocks of Victoria owe their auriferous character to the same cause.

He describes the diorites of Victoria as occurring mostly as dikes, varying in thickness from a few feet to several hundred, traversing Upper Silurian strata, and presenting nearly all the ordinary varieties of structure and composition of that rock. They are nearly always impregnated with auriferous pyrites, and are either traversed by or associated with quartz-veins. According to Mr. Ulrich, by far the greater proportion of the quartz-gold furnished by the gold-fields occu- pied by Upper Silurian rocks is derived from dikes of diorite. . . .

The question as to when the auriferous pyrites was deposited in these diorites is of much interest, and one that it will be somewhat difficult to solve. It is, however, probable that in the majority of cases the pyrites was contemporaneous with the consolidation of the rock in which it occurs, although it is also possible that it may have occasionally owed its origin to the subsequent passage through the rock of metalliferous solutions. . . .

"Below the water-level, which usually very nearly coincides with the zone of decomposition, veins of a class which, on the whole, have proved very misleading to the miner, although often rich in gold, usually disappear. These follow the lines of jointing of the rock, and are probably due to the decomposition of auriferous pyrites and the re-deposition, from solution, of a portion of its material in local fissures. . . . Besides the veins above referred to, there are, associated with the intrusive auriferous rocks, others which Mr. Daintree considers as being of far greater practical importance, from being generally of greater width and more likely to be persistent in depth. These he regards as the result of hydrothermal agen- cies which preceded and accompanied the protrusiony* and which in some cases con- tinued long after the intrusive rock had cooled down.''

Again, I quote the following if

"Daintree, Hacket, Wilkinson and others have shown that a large portion of the gold in Victoria and Queensland is due to the agency of intrusive dikes of felstone, elvan and diorite, so that reefs of quartz in Silurian rocks are not, as was at one time supposed, the exclusive source of Australian gold.

At Timbarra, gold is found in granite ; these gold-fields consist of a granitic tableland, traversed by dikes of eurite and pegmatite, also occasionally showing veins of auriferous quartz, which may possibly be segregation deposits, i The weath- ered granite is sluiced, and very fine gold, to the extent at times of 5 dwt. to the ton, is obtained. Oold has been found to occur here in unaUered granite, and in eurite, as well as in the decomposed granite.''

In the Transvaal, in the Lydenburg district, a quartz-vein in a diorite dike was worked at Waterfall creek,T[ and at Ophir Hill is a silicified bed of dolomite, which has been —

The italics are mine.— J. E. S. f Op. cf<., p. 649.

t " Alaskite."— J. E. S. § The italics are mine.— J. E. S.

II The italics are mine. — J. E. S. Phillips and Louis, op. eiLy pp. 734-5.

lONBOUS ROOKS AS RBLATBD TO OCGURRBKGE OF ORBS. 821

"mineralized by gold-bearing solutions, wbich are in some way connected geneti- cally with the numerous dioritic dikes that traverse the district." In the De Kaap district the rocks, both stratified and granitic, are traversed by dikes of di- orite and pegmatite. ... In the neighborhood of the granite, these rocks occa- sionally cany small ferruginous intercalated deposits, which are generally aurif- erous. . . ."

3. The Subordinate Connection of Gold-Quartz Veins with Basic

Igneous Bocks.

To avoid misunderstanding, I wish to say here that I recog- nize the fact that gold-quartz veins may occur in or near basic intrusives, and may, indeed, be genetically dependent on them. In the Kolar gold-field in India, for example, the auriferous veins invariably occur in a band of " greenstone trap."* In Western Australia the veins are reported to occur chiefly in diorite and diabase, f But certainly an overwhelming majority of gold-quartz veins occur in connection with rocks of the dioritic and granitic families, — that is to say, with the two most siliceous families of the three which make up most igneous rocks; and of these granite-diorite rocks, the veins show a decided preference for the more siliceous groups, such as quartz-diorite (tonalite), granite and alaskite. On the other hand, the intimate genetic connection of these typical gold- quartz veins with distinctly basic rocks, such as those of the diabasic family, may be safely called exceptional.

Therefore, the statement may be formulated that although gold is present in all igneous rocks, and may be unequally distributed in any of them, yet the conditions for concentration by magmatic segregation become rtuyre favorable in proportion as the rock becomes more siUceous and become most favorable in vjhat has been shown to be the extreme siliceous product of rock-differentiation — in quartz- veins or dikes.

The explanation of this is a problem for future study.

X. Rbsumb op the Evidbnce Concerning the Preference OF Certain Metals to Accumulate, by Magmatic Seg- regation, IN Certain Rock-Types of the Established Classification.

I have already pointed out that if the rarer elements, which have been disregarded in establishing the classification of igne-

PhiUipe and Louis, op, eiL, p. 568. f Phillips and Louis, op, city p. 700.

322 Igneous Rooks As Related To Occurrence Of Ores.

0U6 rocks, find themselves, as a result of magmatic segregation,' more closely associated with certain of these rock-types than with others, it is not due to any merit in the classification, but because of the association of these elements with the commoner ones on which the classification is based. In proportion as this association is strong, the preference of a metal for a cer- tain rock becomes more marked. These, then, are some of these preferences :

1. Basic Rocks.

Iron, as is well known, is most abundant in basic rocks, and iron-ore deposits formed directly by magmatic segregation are mostly confined to such rocks.

Chromium ore-deposits, due to magmatic segregation, are chiefly confined to the most basic rocks (peridotites) and their alteration products (chiefly serpentine).

Platinum. — Platinum also is characteristic of the most basic rocks (peridotites and serpentine).

Nickel is frequently closely associated, as the product of magmatic segregation, with iron, chromium and platinum, and is especially found in the most basic rocks.

Vanadium is chiefly found in basic rocks.*

Copper. — On account of its easy mobility, copper occurs in many different rocks, and as the result of many varied pro- cesses. Yet it seems to be especially connected with, and at home in, basic rocks. De Launay saysif "Copper is geologically close to nickel, with which it is frequently met, notably in the peridotites of Canada, for, like nickel, it is, above all, a metal of the basic rocks. ..."

2. Siliceous Rocks.

Molybdenum is chiefly found in connection with the siliceous igneous rocks.

Tin is seldom met with except in connection with granite.

Tungsten has practically the same associations as tin.

The rarer elements in general seldom occur in notable amount, except in pegmatites and granitic rocks. J

BSmnU by J. F. Kemp, Ore- of the United States and Oanaddy 3d edi- tion, p. 36.

t 'Contribution d, Ttude des Gttee Mtallifdres,'' Annales des MineSf Aagost, 1897, 9th series, vol. xii., p. 191.

I Kemp, Ore-DeposiU of the United Stales and Oanada, 3d edition, p. 36.

Igneous Rocks As Related To Occurrence Of Ores. 328

Gold, as has just been argaed, while a mobile metal and widely distributed, seems to show a preference for the siliceous igneous rocks.

XI. The Relation between Orb-Deposits Dub to Magmatic Segregation anp Other Orb-Deposits.

In nature there are no hard and fast lines. So we find that ore-deposits originating, b& argued, by magmatic segregation, pass by transition stages into others whose characteristics de- ' mand a different interpretation.

Especially close is the connection between certain magmatic segregations, certain contact-deposits, and certain deposits of gaseous-aqueous (pneumato-hydatogenic) origin.

Magmatic segregations take place while the rock, as a whole, is yet liquid; they are due to the mobility of elements or crys- tallizing minerals in this liquid, and may be conveniently con- ceived as taking place through the action of convection-cur- rents.

Upon the cooling of an igneous intrusive rock, however, what might be called a forced segregation takes place. As the rock becomes solid, those materials which are " left-over " are expelled, and find their way into the neighboring rock, or along the fissures of the igneous rock itself. These " left-over " ma- terials consist chiefly of water, which is usually highly silice- ous, and contains a great variety of other mineral matters in solution, and also, very commonly, an unusual quantity of gases. In these excretions the proportion of gaseous to liquid constituents appears to vary as widely as possible — dependent, probably, partly on the nature of the cooling rock, partly on the conditions or rate of cooling, etc. According as the gase- ous or the liquid elements preponderate, there result ore-de- posits (for these expelled solutions often contain metals), which, from the internal evidence they offer as to their mode of for- mation, may be classed as pneumatogenic (pneumatolytic), pneumato-hydatogenic (gaseo-aqueous), or hydatogenic. To the first class belong the ores deposited by volcanic fumaroles, and the writer has referred the gold-ores of Mercur, Utah, to the same general division. The second and third classes are

J. R Sparr, Economic Geologj of the Mercur Mining District/' I6ih Ann. RpL v. & GeoL Survey, Part IL, p. 462.

324 Iqnbous Rocks As Related To Occurrence Of Ores.

of great importance. To the second belong the tin-veins, and to the third the " contact-deposits " proper.*

The gold-quartz veins, such as have been considered to be formed by magmatic segregation, the veins of the tin-group, and the contact-deposits proper, are perfectly distinct in char- acteristics and origin ; yet between the first and the second, and the second and the third, there are all transitions, indicat- ing transitions in the conditions which produced them. In all three cases the mineralizing agents may be described as highly- heated water heavily charged with silica, and containing metals and other mineral matters, all being directly derived from an igneous rock in its last stages of consolidation from a molten condition. All are characteristic of the more siliceous intru- sives. Tin-veins seem to be confined to granitic rocks ; gold- quartz veins prefer granite, and after that diorite ; while con- tact-deposits, like contact-metamorphism in general, are chiefly characteristic of the more siliceous rocks, granite or diorite. Yet the first may be conceived of as quietly segregating under pressure in a mobile though probably slowly congealing magma, the second as escaping from a cooling-rock into fissures or other channels, with relief of pressure and the consequent assump- tion of diflferent form and proportion, and the third as also escaping from a cooling-rock, but under pressure and penetrat- ing largely by capillary or osmotic action into the rock in con- tact with the igneous body. Each of these processes involves a different selection of elements by the solutions — Whence tin- veins and gold-quartz veins are generally quite distinct.

Many pegmatites are closely related to tin-veins. They not infrequently contain cassiterite, and are characterized by fluor and boron compounds, indicating gaseo-aqueous origin. Such pegmatites, like the true tin-veins, are not likely to contain gold, and cannot be taken as ah indication of probable gold- quartz veins. On the other hand, pegmatites containing slight evidence of pneumatolytic origin may be closely related to and associated with gold-quartz veins. In some pegmatites gold has been found. But the quartz-veins that pass into relatively

J. H. L. Vogt, "Problems in the Geology of Ore-Deposits," Trans,, xxzi., pp. 139, 140. Oenena of Ore-Deposits, pp. 650, 661. Waldemar Lindgren, "Char- acter and Genesis of Certain Contact-Deposits,'' Trans., xzxi., p. 226. Omesis of Ore-Deposits, p. 716.

Ignbous Rocks As Related To Oogurrengb Of Orbs. 825

fine-grained, highly siliceous igneous rocks, with slight display of coarse-grained pegmatite, have probably been formed under the most favorable conditions for the segregation of gold in them, i.e., comparative freedom from the pneumatolytic actions which are so unusually important in forming the cassiterite veins. Yet the occasional presence of tin and its close asso- ciate, tungsten, as well as tourmaline, fluorite, etc., in gold- quartz veins shows that one set of conditions may pass gradu- ally into the other. The occasional presence of tourmaline, fluorite, wolframite, tin, etc., in zones of contact-metamor- phosis and in contact ore-deposits, contrary to the usual occur- rence, is an illustration of the same principle.*

Xn. The Sequence of Volcanic Eruptions Considered in Connection with the Sequence of Metalliferous Veins.

It has already been described how, in a certain volcanic field, the rocks erupted or intruded at different periods are of quite different character, and how dissimilar rocks may be most closely associated. Extremely acid and extremely basic rocks are often almost or quite contemporaneously intruded or erupted in the same locality. From this, and from the ob- served sequences, rough laws of succession have' been de- duced. These diffier somewhat, according to the district in which observations were made in each case ; but they practi- cally agree in indicating that magmas tend to segregate into more basic and more acid (more and less siliceous) portions. The writer, following Professor J. P. Iddings, believes that an initial rock of intermediate composition ordinarily passes, by magmatic segregation, into rocks which are progressively more acid and more basic, till extremely siliceous and extremely basic varieties are obtained. According to this, if the rocks were regularly intruded or erupted at stated intervals, we might expect to find the law of segregation fully illustrated in the succession of rocks. Sometimes, indeed, this is the case ; but very often the eruptions have taken place irregularly, so that the normal succession is hardly recognizable.

Prof. J. P. Kemp has called attention to cases of successive

Compare J. H. L. Vogt, PioblemB in the Geology of Ore-Deposits," Trans., zxxL, p. 139. Genegie of Ore-DepositSf p. 650.

826 Igneous Rocks As Related To Occurrence Of Orbs.

vein-formations of quite different characteristics in a single district, and has supported the idea that new intrusions of igne- ous rock, of a character different from the preceding intrusions (rather than new fractures, as has often heen assumed), are responsible for the differences, the metals extracted from one igneous rock being different from those derived from another.* With this idea the writer is in general accord, and would add the suggestion that also the difference in the veins at different periods may often depend upon the progress of rock-segrega- tion (differentiation) in a still unconsolidated magma, from which the metals, directly or indirectly, are derived. By apply- ing the idea of the change of segregated metals with the prog- ress of general rock-segregation, some light on mineral asso- ciation and succession may possibly be obtained. For example, in many districts of the world gold and platinum are closely associated in placers. In these districts it is usual to find ex- tremely acid and extremely basic rocks (complementary varie- ties) intimately associated, representing apparently an extreme stage of rock-segregation ; and frequently, as in the Urals, the platinum is found to be derived from the basic rocks (perido- tites), and the gold chiefly from gold-quartz veins in the sili- ceous ones (granite). This is one of the simplest cases. In an earlier stage of the rock-segregation, when the extreme rock- types had not originated, we would not find any platinum- segregations, and the occurrence of gold-quartz veins would be less probable. A similar example of mineral association, probably dependent upon rock-segregation, is the occurrence in the gold-quartz district of Forty-Mile creek, Alaska, of an ore containing nickel, iron, chromium and magnesia, and no gold.f Just as the gold-quartz veins here are intimately asso- ciated with the ultra-siliceous dikes, so this ore is probably con- nected with the ultra-basic ones; and, as the two sets of dikes have been considered complementary and due to a single pro- cess of segregation, the contrasted ore-formations must be considered in the same light.

In many districts it has been noted that the veins of different

Igneous Bocks in the Formation of Veins," Trans., xzxi., p. 180. Oenesis of Ore-Deposits, p. 691.

t J. K Spurr, " Geology of the Yukon Gold -District," 18 Ann. Bep, U. 8. (?. 5L,PartIIL, p. 295.

Ignbous Rocks As Related To Occurrence Of Orbs. 327

periods have different contents. Professor Kemp* has called attention to the San Juan region in Colorado, where the differ- ent veins have been classified by T. B. Comstock as follows : 1. The northwest system with tetrahedrite. 2. The east and west with bismuth, and less often nickel and molybdenum. 8. The northeast with tellurides and antimony, and sulphur-com- pounds of the precious metals.

The same writer cites, in this connection, the Telluride dis- trict in Colorado, where a heavy vein is cut out and faulted by a later one of different metalliferous character. He also re- calls an occurrence near Freiberg, Saxony, where seven sets of veins have been recognized, distinct from one another min- eralogically, and probably introduced at different periods. At Butte, Montana, there are two distinct sets of veins, one con- taining silver and no copper, and the other containing copper, silver and gold.

At Mercur, Utah, the writer has described two ore-bearing zones which are parallel and lie about 100 to 150 ft. from one another. t They are of different ages: the oldest, the " Silver Ledge," contains silver with only traces of gold, while the younger, the " Gold Ledge," contains gold to the exclusion of silver, together with cinnabar and realgar, minerals not found in the Silver Ledge.

This list might be amplified, but will serve to show the main features of the problem.

It is not safe or reasonable to refer such differences in veins to any one universal cause. In the Mercur case, the writer has reasoned that the Gold Ledge is essentially a pneumatogenic deposit, due to gases ascending along fissures; and that the Silver Ledge is a contact-deposit, due to waters occluded in cool- ing from the intrusive sheet of rhyolite porphyry at whose con- tact it occurs. In such cases the different nature of the miner- alizing solutions is sufficient to produce entirely different com- binations of vein-minerals derived fi*om a single magma, al- though a change in this magma itself by segregation, or the

" Igneoos Bocks in the Fonnation of Veina,'' Tram., xxzi., p. 179. Also Ort'Depodts cf United States and Oanada fourth edition, p. 288. Oeneais of Ore- Deponls, p. 691.

t J. R Span*, " Economic Geology of the Mercur Mining District, Utah,'' I6lh Ann, Rep, U, S. OeoL Survey, Part IL, p. 403.

328 Igneous Rocks As Related To Occurrence Of Orbs.

intrusion of a rock of a new kind is, of course, not improbable. In other cases the different character of rocks traversed by the same mineralizing solutions might operate to cause the precipi- tation in one rock of a different combination of minerals from that precipitated by another. Where, however, the different veins are in the same rock, and belong in the same category of ore-deposits (from the standpoint of the process of formation), the assumption of a change in the character of the igneous rock below, whether by new intrusions (mechanical change) or by segregation (chemical change), will probably be often justified. The fact that the different veins often occupy frac- tures of different trend and age is far from opposing this theory, for it is only by the aid of mechanical accidents like fracturing that new solutions can rise, and by their effects bear witness to the change that would otherwise not be known.

XTTT. The Persistence of Pbtrographic Provinces, Consid- ered IN Connection with the Persistence of Metal- liferous Provinces.

While an igneous rock of a certain kind is not necessarily limited to a certain part of the earth's surface, yet the rocks of a given district generally show marked and persistent differ- ences, taken as a whole, from the rocks of other, even adjoin- ing, regions. To these districts, showing within themselves, no matter how varied the rocks they contain, a certain " kin- ship " or " consanguinity " between the different rocks, the term petrographic provinces has been assigned.

For example, many of the rocks of northern Minnesota, es- pecially the granites, show a constant excess of soda over pot- ash, producing the variety soda-granite, which appears to be characteristic of this region.* Other regions have a large de- velopment of rocks especially high in the alkalies, — phonolites, nepheline-syenites, etc., rocks which in most regions are want- ing. Rocks characterized by an especially great proportion of magnesia, such as peridotites, occur in certain regions and are wanting in others.

The differences which give rise to these petrographical prov- inces are evidently due to the unequal distribution of the com-

2l9t Ann. Rep. Minn,, OeoL, and Nat, Hist Survey, PP* 41, 42.

IGNBOTTS BOCKS AS RELATED TO OCGUfiRBNGB OF ORBS. 829

moner rock-forming elements, upon which rock-classification is based, in different portions of the earth's crust. In one region sodium is especially abundant, in another both sodium and potassium, in another magnesium, in another aluminum, etc. Some petrographic provinces show mineralogical differ- ences which are wonderfully slight, considering their persist- ence— in one the granites may be chiefly hornblende granites, for example, and in another almost entirely biotite granites, owing to constant, slight differences in the proportions of alu- minum, magnesium, calcium, potassium, etc., present in each. The existence of these petrographic provinces, characterized by different proportions df the commoner rock-forming ele- ments, has been explained by extending the theory of rock- segregation or differentiation so as to make it applicable on a large scale, and by supposing that in great internal reservoirs (presumably connecting, or at least once connected) certain ele- ments, by reason of their affinity, become more or less concen- trated in certain portions. We are quite in the dark as to what might be a possible cause for this (as yet) hypothetical process, for certainly the theory of concentration by convection-cur- rents on cooling has slight application here ; but in science the apprehension of the fact very commonly runs ahead of the explanation, and this idea is at least a good working hypothe- sis, which has much to recommend it. By this theory all igne- ous rocks (in so far as they are not formed by fusion of sedi- mentary rocks or by mixing of already different magmas) have originated chiefly by segregation from an original universal magma.*

If one accepts as a working hypothesis {as the writer has done) this theory that the unequal distribution or the relatice concentration of the commoner rock-forming elements in certain parts of the eartKs crust {giving rise to distinct petrographic provinces and rock-types) has been effected by magmatic segregation ofnje cannot avoid accepting the same theory for the less common rockforming elements.

If one accepts this for the distribution of sodium, potassium, aluminum, magnesium, titanium and phosphorus, he must ac- cept it for manganese, barium, chromium, nickel, strontium, lithium, chlorine and fluorine; and if he applies it to these

J. P. IddingB, " The Origin of Igneous Bocks," PhUosoph, Soc Wash,, vol. xiL, p. 185.

830 Igneous Rocks As Rblatbd To Occurrence Of Orbs.

latter, he must extend it to tin, bromine and cobalt; to lead, zinc, copper, arsenic, antimony, wolfram ; to. mercury, silver, bismuth, vanadium, tellurium and thorium ; to gold and plati- num, and even to iridium, ytterbium and germanium.*

Following this idea, and observing that some regions are especially rich in sodium, some in magnesium, and some in titanium (petrographic provinces), we should expect to find some especially rich in chromium, some in nickel, some in tin, some in lead, some in copper, some in mercury, some in gold, some in platinum, etc. This is well known to be the case, and these regions, characterized by special combinations or amounts of the rarer, especially the commercially- valuable, metals, I de- sire to call metalliferous provinces.

A metalliferous province does not necessarily coincide with a petrographic province, for the reason that I have already pointed out — namely, that the petrographic province and its contained rocks is classified solely on the basis of the com- moner rock-forming elements ; while the rarer ones, upon the distribution of certain of which metalliferous provinces may be distinguished, follow independent laws of segregation, which, nevertheless, may sometimes partly coincide with the laws of segregation of some of the commoner elements, by virtue of an affinity or preferential association between a rare element and a common one.

The helpfulness (to the investigator) and yet the final unre- liability of these affinities will be at once seen upon considerar tion. Platinum, for example, is undeniably most abundant in basic rocks — peridotites ; that is to say, it prefers the company of elements like magnesium, calcium or iron, and objects to that of silicon ; yet all peridotites do not contain platinum, at least in equal amount. It is only in certain metalliferous prov- inces that platinum is sufficiently abundant in peridotites to be- come commercially interesting. The same remarks apply to chromium, nickel, etc. On the other hand, tin seems to prefer the society of silicon, and is always found in close connection with siliceous igneous rocks, chiefly granites; yet not all granites contain tin in notable quantities. The variation is

For the reUdye propoTtion of the elements in the earth's crust, see F. W. aarke, BtUL U, S. Q. S,, Nos. 78 and 148 ; also J. H. L. Vogt, Ueber die xela- tiye Verbreitung der Elemente/' ZeiUeh. fur praktitche OeoLf 1898, p. 226.

Igneous Rocks As Related To Occurrence Of Orbs. 331

enormous. So a study of the distribution of granite gives only a slight clue to the distribution of tin, and a knowledge of the occurrences of peridotite is only the first step toward a knowl- edge of the occurrences of chrome or nickel deposits. This principle is of wide application. Igneous rocks have long been recognized as the ultimate sources of many, if not most, ore-deposits. Yet not all igneous rocks are connected with ore-deposits. One mass of diorite, for example, may be con- nected with rich ore-bodies (formed, it is needless to say, in most cases, finally through the concentrating action of circulat- ing waters), while an exactly similar diorite in another region may have no ores at all associated with it. One may explain this by assuming that in the first-mentioned case there have been abundant circulating waters, especially heated ones, and plentiful faults, fractures and zones of weakness permitting the passage of these mineralizing agents ; and that in the second case these conditions for concentrating the disseminated metals have not been so favorable. The writer recognizes these con- siderations as of vast and universal importance ; and yet a com- parison of regions equally favored with igneous intrusives, with abundant circulating waters, with the necessary channels for circulation and permeation, and with rocks favorable for the precipitation of the metals held in solution in the circulating waters (such as limestones, carbonaceous shales and porous sandstones), may show an utter difference in the amount and nature of the minerals concentrated. Moreover, the same type of rock — a diorite, for example — may be associated with chiefly silver-ores in one region, with copper in a second, and with gold in a third.

Detailed investigations concerning the less abundant metals in igneous rocks, although they have rendered the science of ore-deposits the inestimable service of proving the presence of these rarer' elements, afford little ground for more extended conclusions, on account of their being so few and (necessarily, from the minute quantities dealt with) so inaccurate.

Yet it seems that they also corroborate the conclusion that the metals are very unevenly distributed.

Professor J. F. Kemp remarks:*

" Tbe K61e of the Igneous Bocks in the Formation of Veins," Tram., p. 172 ; also, Oenesis of Ore-DepoaiiSy p. 684.

382 Igneous Bocks As Rblatbd To Ogourrence Of Ores.

'' Neyertheleas, it is a fact of the greatest importance that the presence of the metals* in the igneous rocks has been established. Not all igneous rocks have yielded such results on assay. The general experience has been that when sam- ples of several varieties have been collected in a given district, some have proved barren ; and it must be admitted that some negative results have been obtained. As a rule, however, they are decidedly fewer than the positive results. It is likewise true that not all igneous districts contain veins of ore.''

To this quotation the writer adds the suggestion that most of the assays made have been of igneous rocks in metalliferous districts, where we should a priori (according to the ideas pre- viously set forth) expect a greater proportion of the metals ; and that, if assays of rocks in non-metalliferous districts were made, the proportion of negative results might be decidedly in excess — although then, as now, the term negative results" would probably only mean that the metals sought for were in quantities too small to be detected by chemical methods.

The chemical determinations of the presence of the more abundant of the relatively rare metals give results fully con- firming the conclusions reached as to their unequal distribu- tion in similar rocks. Nickel, for example, is recognized . as especially at home in the most basic rocks — peridotites and py- roxenites; but Vogtf gives a table of nickel determinations in 82 rocks of this kind, which vary all the way from a trace to 0.6 per cent.

Petrographic provinces may be relatively small in extent, or they may be enormous. The writer has made a study of the volcanic region of the Great Basin,! where an area whose limits are not determined, but which extends as far east as Salt Lake, west into the Sierra Nevada, north into Idaho and Oregon, and south into California, shows the same types and the same general succession of Tertiary lavas. From later studies by the writer in the Monte Cristo mining district, Washington, it appears that the Tertiary eruptions here also correspond in types, age and general succession to those of Nevada ;§ similar rocks, age and succession have been ob-

Beferring, of course, to the least abundant metals. — J. E. S.

t ''Relative Verbreitung der Elemente/' Zeiisch, fur prakL Oeol., July, 1898, p. 236.

X Journal of OeoLy voL viii., p. 621.

i See article by author on "The Ore-Deposits of Monte Cristo, Washington," 22d Ann, BepL U, S. OeoL Survey, Part II., pp. 711-865.

Igneous Bocks As Rblatbd To Ocgurbencb Of Orbs. 383

served on the Southern California coast;* and as far away as Mexico the studies of Ordonezf have established the fact that the principal rocks, their succession and age, remain the same. Without being in danger of carrying this correlation to excess, I may point out that the Pliocene olivine-basalts of the Sierra NevadaJ are abundantly present in Oregon and Washington; that the British Columbia basalts are approximately, at least, of the same period ;§ and that throughout the whole of Alaska and into the Behring Sea occur olivine-basalts of Pliocene age.||

Again, the abundance of basic andesites (typically augitic, often hypersthene-bearing, and verging towards basalts), all belonging to one epoch (very late Pliocene-Pleistocene), in a continuous belt in Alaska, running the whole length of the Aleutian Islands and peninsula, turning the same angle as the chief orographic and topographic features, and running down the coast past Sitka ;T[ the occurrence of the same rocks, be- longing to the same age, in Washington and Oregon (Mt. Rainier, etc.); the extension of the belt through the Sierra Nevada and along the western part of the Great Basin ; finally its extension into Mexico,** — this is all striking, and deserves recognition. Moreover, this belt of late Pliocene-Pleistocene augite (hypersthene) andesites extends through Central and South America, in the Andes.ft In Alaska and in the Andes some of the cones of this epoch are still active ; but the ma- jority have become extinct.

It appears, then, that the whole extreme western part of the western hemisphere (the Pacific coast of the Americas) is a zone occupied by what (at some periods, at least) is and has been a single petrographic province.

It remains to be seen whether this province is not continued

I regret I have not at hand the paper of Mr. Smith in a recent U. S. Geol. Surrey Ann. Beport, in order to give an exact reference. (Santa Catalina Island.)

t '' Las Bhyolitaa de Mexico," Boletin del IrutUuto Oeoloffico de Mexico, No. 14.

J J. E. Sporr, Jour, QeoLj vol. viii., No. 7, chart, p. 643.

G. M. Dawson, Ann, Rep, OeoL Nat HisL . Canada, vol. iii., Part I., p. 37 B. ; also, Trans, Boyal Soc (hnada, vol. viii.. Sec 4, p. 15.

II J. RSpurr, "Geology of the Yukon Gold-District," ISth Ann, Bep, U, S. QtoL ., Part III., p. 250.

f J. R Spurr, ''Reconnaissance in Southwestern Alaska," 2(Hh Ann, Bep, 17. 8, QeoL Surv,, Part YIL, Map 13.

Esequiel Ordofiez, op, cU,, p. 66.

ft Zirkel, LekHmeh der Petrographie, 2d Edition, Vol. ii., pp. 831-2. voi*. xxxni. — 21

334 Igneous Books As Belatbd To Ocoubbence Of Obes.

into Asia with the change of orogenic trends in Alaska from northwest to southwest. The line of late Tertiary-Pleistocene volcanoes, which extends along the Aleutian Islands to Kam- chatka, is represented by 16 or 20 cones in this peninsula; this line, following the general orogenic trend, runs southwest through the Kurile Islands, the islands of Japan, and the Phil- ippines, into the East Indies. Andesites — largely pyroxene andesites, and frequently hypersthene andesites — are character- istic of this chain also, as far as the famous volcano of Kraka- tua. This investigation might profitably be carried still fur- ther, but this is hardly the place for it.

Turning from these examples of petrographic provinces on enormous scales, we find that metalliferous provinces may also be of light extent, or may be exceedingly large. Taken broadly, they often coincide more or less roughly with petro- graphic provinces, just as these ane apt to show some corre- spondence in their position and trends with zones of folding and fracture in the crust, with mountain ranges and the bor- ders of continents. A metalliferous province which I have been studying somewhat lately is the rich chrome-bearing province of Turkey, which, with its center at the western coast of Asia Minor, extends across the gean Sea and includes Macedonia and Eastern Greece, and in the other direction stretches over the western and southern portions of Asia Minor. This metal- liferous province is connected with a petrographic province marked by ultrarbasic igneous rocks and serpentines, with which the ore is associated; yet similar rocks are found in other regions, without the corresponding abundance of chrome.

Taking a larger example, compare, in North America, the Appalachian with the Cordilleran region. That there is a cer- tain kinship among the ores of the Appalachian chain and its allied ranges has long been recognized by mining men. It is recognized that the metals though present are constantly far less abundant than in the Cordilleran region. Every now and then one hears of veins found in this region which give rich results on assay; but the discovery, though heralded in the news- papers, makes no disturbance in the mining world, for the mining man knows, from long experience with such discoveries, that the vein will directly " peter out." Gold-bearing veins

Ignbous Rocks As Related To Ogourrenge Of Ores. 835

are pretty thoroughly scattered along this zone from Nova Scotia to Georgia ; but the uncertainty and the relative poverty of these gold-deposits is proverbial.

Taking the western Cordilleras, on the other hand, we may remember that the California miners followed new finds north- westward, along the trends of the mountain ranges, into the Frazer river country, the Caribou district, the Omenica, the Cassiar, the Pelly, and the Yukon, until the slow progress has brought them to the neighborhood of the Behring Straits (the Nome district). It seems exceedingly probable, also, that this true " mineral zone " extends into Siberia. For I do not hesi- tate to call it a mineral zone, although the gold-quartz veins of the Yukon are far different in age from those of California. In fact, the existence of rich gold-ores along this zone, in deposits of various ages, and made under various conditions and in various rocks, only serves to emphasize the conclusion that this zone is essentially a metalliferous province, marked ty greater proportion of gold (considering the question of the gold alone) than the earth's crust in general.

Concerning metalliferous sub-provinces within the Cordil- leras, I quote the following from Phillips and Louis,* not having access to the original authorities :

" Mr. R W. Raymond, t in a paper on the mining districts of tbe United States, recaUs the fact that W. P. Blake, in a note to his OcUalogue of Oalifomia Minerais first pointed out that the mining districts of the Pacific slope are arranged in parallel zones, following the prevailing direction of the mountain ranges. More recently, Clarence King has summarized these phenomena nearly as follows: The Pacific coast ranges carry, on the west, quicksilver, tin and chrome iron-ores. The next belt is that of the Sierra Nevada and of the Cas- cade mountains of Oron, which, upon their western slope, carry two distinct zones, a foot-hill chain of copper-mines, and a middle line of gold-deposits, which extend into Alaska. Lying to the east of this zone, along the eastern base of the Sierras, and stretching southward into Mexico, is a chain of silver-mines which are frequently included in volcanic rocks. Through Central Mexico, Ari* zona, Central Nevada and Middle Idaho there is another line of silver-mines which more often occur in the older rocks. Through New Mexico, Utah and Western Montana lies another zone of argentiferous galena lodes ; and again, to the east, the New Mexico, Colorado, Wyoming and Montana gold-belt forms a well-defined and continuous chain of deposits. Raymond agrees that this paral- lelism exists, though in a somewhat irregular way, and that it is chiefly referable, as Blake and King have shown, to the structural features of the country.''

This quotation the writer makes without deciding his belief

Ore-DeposiU, 2d ed., p. 740. f Trans,, i., p. 33 (1873).

336 Igneous Rocks As Related To Occurrence Of Ores.

for or against the divisions as claimed. Undoubtedly the later discoveries within this region have been so varied as to make some of the distinctions doubtful ; yet a careful consideration of the Cordilleran ore-deposits of western North America would probably result in the determination of definite metal- liferous sub-provinces, which might or might not coincide with those specified. That Nevada, in general, is part of such a sub-province, characterized especially by the abundance of sil- ver, with other minerals subordinate, is strikingly illustrated by the fact that thte vigorous mining industry of this State, so exceedingly rich in ore-deposits, was permanently prostrated by the decline in the price of silver, while other regions, differ- ing from this in the nature of their metallic wealth, have pros- pered.

XIV. Conclusion.

Our inquiries lead us to the hypothesis that by magmatic seg- regation the metals of commercial valtiCy as well 05 the other rock- forming elements, are irregularly and to a certain extent independently concentrated in certain portions of the earths crust. Such portions, characterized by the relative abundance of certain metals, may be called metalliferous provinces. It is in these provinces that ore- bodies will generally occur. The provinces may or may not be closely identified with petrographic provinces (divisions based on the relative abundance of the commoner metals and other elements), although, by reason of the chemical affinity which exists between certain of the rarer metals and certain of the commoner elements, they probably generally do so, to a certain extent at least. Moreover, within these metalliferous provinces (as is the case within the petrographic provinces) magmatic segregation produces sub-provinces, secondary, perhaps, in theoretical importance to the grander divisions, but of more practical interest to miners. To limit, again, the scope of our views, by magmatic segregation the rarer metals (like the commoner elements, again) are in many cases preferentially concentrated into certain rocks in a given sub* province. Finally, vAthin these rocks the metals may be segregated chiefly into certain portions, even producing, in the case of the com- moner metals {iron, chrome, nickel, etc.), workable ore-deposits with- out further concentration ; and, in the case of the less common ones, either directly producing workable deposits {certain gold-quartz veins, certain tin-veins, possibly certain platinum segregations — Urals — )

Igneous Rocks As Related To Occurrence Of Orbs. 837

or jyroducing rocks relatively so rich that it requires only the concen- trating action of other agents {chiefly circulating waters) to create " ore-bodies" It is the writer's belief that the origin of metal- producing districts as contracted with barren districts is in most cases due primarily to magmatic segregation, and that an important class of ore-deposits is due directly to this.

Added to this initial process, there are the varied effects pro- duced by gases and liquids occluded by cooling igneous rocks, and the enormous work of waters, surface and underground, which, by continued solution and deposition as well as by me- chanical concentration, may, under favorable conditions, operate to bring the disseminated metals within smaller and smaller compass. Underground, these waters may be hot or cold ; they may be ascending, descending, or moving laterally ; they may transport their metallic load only a fraction of an inch, a few rods, or miles. Their final effect is to create directly what is, perhaps, the most important type of ore-deposits. The study of ore-deposits is a study in concentration — the concentration of some of the finely-disseminated rarer rock-forming elements into more or less compact masses. This concentration is ef- fected chiefly by these processes : (1) magmatic concentration ; (2) concentration by occluded gases and liquids from consoli- dating magmas; (3) concentration by the action of hot-spring waters (generally ascending) ; (4) concentration by the action of cold surface-waters penetrating underground (generally de- scending); and (5) concentration by the effects (chiefly me- chanical, though largely chemical) of surface-waters at the surface.

Any one of these processes may be chiefly responsible for a given ore-body, but in many cases two, three or more of them may be important. Moreover, the history of an ore-deposit may comprise cycles, or repetitions of the same processes at different intervals, before the final concentration is sufficiently complete. Take, for example, the Nome beach-sands, where the gold is concentrated from the concentrates of older beach- sands, now transformed into land by a crustal uplift.*

On Napoleon creek, a branch of Forty-Mile creek, Alaska, there was found a strip of rich stream gold-placer ground in

Schimder and Brooks, TrauR,, xzx., p. 242.

338 Igneous Rocks As Related To Occurrence Of Orbs.

a district where working was not otherwise profitable. 'The gold was apparently derived from a conglomerate of probable Cretaceous age which formed a belt crossing the stream at this point. The composition of the conglomerate showed that it was derived from the rocks and quartz-veins of the ancient ( Algonkian ?) gold-bearing series. In this ancient series, as al- ready explained, the gold is believed to have been concentrated by magmatic segregation. Here, therefore, we have three dis- tinct processes of concentration: (1) magmatic segregation (Algonkian ?) ; (2) mechanical concentration by surface-waters (beach-sands — Cretaceous?); (3) mechanical concentration by surface-waters (stream-placers — Pleistocene). And it was only after the third process that the metal was sufficiently concen- trated to become workable with profit — to become an ore-de- posit, properly speaking.

Postscript.

Since the above was written, the writer has received the in- teresting paper of Mr. Luther Wagoner on " The Detection and Estimation of Small Quantities of Gold and Silver."* Mr. Wagoner gives a series of delicate assays of California rocks, remote from mineral deposits, for gold and silver.

Four specimens of granite gave respectively the following weights in milligrams per ton: Gold, 104, 137, 115, 1130; silver, 7660, 1220, 940, 5590. One specimen of syenite showed gold, 720 ; silver, 15,430. A sample of diabase contained gold, 76 ; silver, 7440 ; and one of basalt, gold, 26, silver, 547. The sedimentary rocks tested were three specimens of sandstone from different localities, and two of marble (one of the latter from Italy). The sandstones gave respectively, in gold, 39, 24 and 21 ; in silver, 540, 450 and 320. The California marble showed gold, 5; silver, 212; the Italian sample, gold, 8.63; silver, 201. Several assays of San Francisco bay-mud (contain- ing some organic material) gave gold from 45 tp 125. Two assays of sea-water gave a mean of gold, 11.1 ; silver, 169.5.

These results are suggestive ; and, although too few to base final conclusions on, the writer would" like to call attention to some striking facts. On reckoning up the means of the re- sults, we find that the granite averaged 371.5 gold and 3852.5

IVaiM., xxxL, p. 798.

Igneous Rocks As Rblatbd To Oocurrencb Of Orbs. 839

silver; the sandstone, 28 gold and 436 silver; the marble, 6.8 gold and 206.5 silver; and the bay-mud, 85 gold.

The relative proportion of the precious metals in the sedi- mentary and in the igneous rocks first claims attention. The mean of all the igneous rocks assayed in gold 329, and silver 5546; of the sedimentary rocks (sandstones and marbles, not the bay-mud), 17.5 gold and 344.4 silver. That is to say, the mean of the igneous rocks assayed shows about 19 times as much gold and 16 times as much silver as the mean of the sedimentary rocks.

The relative proportion of the metals in the diflferent sedi- mentary rocks is another point. The sandstones average 4 times as much gold and over twice as much silver as the mar- bles ; while bay-mud (which on hardening would become shale) contains nearly 13 times as much gold as the marbles.

Take, next, the relative proportion of the metals in the differ- ent igneous rocks. We have in the list siliceous or acid rocks (granite and syenite) and basic rocks (diabase and basalt).

Diabase and basalt are, generally speaking, chemical and mineralogical equivalents, differing in their texture and struc- ture. If we compare the average of the granites with that of the diabase-basalt, we find that the former is 371J gold and 3852 silver, while the latter is gold 51 and silver 4008 ; that is, the granites contain nearly times as much gold as the diabase-basalt, but only about the same quantity of silver. If we add the syenite assay (probably unusually high) to those of the granites, and again compare the result with the diabase- basalt contents, we find that the acid rocks contain 9 times as much gold and times as much silver as the basic ones.

In spite of the small quantity of data, these results are in accordance with the theoretical conclusions arrived at in this paper. One of these conclusions was concerning the higher content of precious metals in the igneous rocks as com- pared with the sedimentaries. A second conclusion was in regard to the relative concentration of the metals in the dif- ferent sedimentaries — least in the limestones, which are calcium concentrations effected largely chemically from the sea-water through organic agencies ; more abundant in the sandstones, which are silica concentrations, but effected mechanically and containing much dibris from all sorts of rocks; and most

840 Gbolooic Deposition Of The Htdrooarbons.

abundant in the bay-mud, which is a fine ground-up mixture of all rocks, and contains, besides, organic matter which is known to be a precipitant of metals from solution. A con- tinuance of these experiments is highly desirable, to fix the point as to whether the order of richness in gold and silver of the sedimentary rocks is really 1, shales; 2, sandstones; 3, limestones.

Thirdly, as regards the igneous rocks, the uniformly superior gold content of the siliceous or acid rocks, as compared with the basic rocks, is noticeable. One must remark, also, that the same does not hold good for silver ; for, although the basalt con- tains the least and the syenite the most, yet the diabase has a large amount. This, as far as it goes, is in accordance with the theory above advocated, that during the process of mag- matic segregation the gold (jiot the silver) seeks the siliceous rocks by preference.

Principles Controlling the Geologic Deposition of the Hydrocarbons.*

BY GEORGE I. ADAMS, WASHINGTON, D. G. (New York and Philadelphia Meeting, Febraary and May, 1902.)

There is an extensive literature relative to gas, oil, and the more solid hydrocarbons ; but when it has all been digested and summarized, the resulting information is far from being satisfactory. The problems which have received the most attention are naturally those which relate to the successful exploitation and utilization of the deposits. Prom what is known of their geologic occurrence, theories have been formu- lated and rules laid down for the guidance of prospectors. The technology of the products has been made the subject of spe- cial chemical investigations. The geologic interrelation of the hydrocarbons, however, has not been considered in a broad manner, and the principles which have governed the origin of the economic bodies have been but imperfectly expressed.

On the other hand, metalliferous deposits have been widely

Published by permission of the Director of the U. S. Greological Surrey.

Gbologig Deposition Of The Hydrocarbons. 341

studied, and the broader principles of ore-deposition are for- mulated. The paper by Van Hise,* on " Some Principles Controlling the Deposition of Ores," in which the origin of the larger part of the ore-bodies is ascribed to the work of underground water, may be cited as a comprehensive explana- tion of the most important class of metalliferous deposits. A similar explanation of the origin of the hydrocarbons must ultimately be formulated.

It is not purposed here to attempt the formulation of such a theory. The facts are altogether too few or too imperfectly known to admit of it. If, however, we follow the lines of reasoning suggested by the principles controlling ore-deposits we shall be led to fruitful inquiry, and experimentation will be suggested which should ultimately be taken up.

Accepting the organic origin of the natural hydrocarbons, we may divide all noteworthy deposits of such materials in the earth's crust into :

(1) Those resulting from sedimentation.

(2) Those accumulated through underground circulation. As accumulated bodies, resulting from sedimentation, may

be mentioned coals, lignites and fossil gums. The dissemi- nated hydrocarbons of this class are found in carbonaceous shales, pyroschists, bituminous limestones and other sedimen- tary rocks with which they were deposited, and from which they have not been transferred; they include shale. gas, marsh gas, and the small quantities of solid and fluid hydrocarbons which are of little economic importance.

The hydrocarbons which have accumulated through under- ground circulation are natural gas and petroleum in reservoirs, and maltha and asphalt in fissures and openings. The dissem- inated occurrences of this class are the hydrocarbons found impregnating sedimentary and occasionally igneous and meta- morphic rocks, which originally held no such material. They are in solid, liquid or gaseous form.

It is appropriate to mention here the forms of carbon, — natural coke, graphite and diamond, — which are chemically the simplest products of the same general processes which produce the complex hydrocarbons, and which, like them, may have organic matter as their original source.

Trans. f xxzi., p. 284, and Oenegis of OrerDeposiU, 282.

342 Geologic Dbpobition Of Thb Hydrocarbons.

This discussion deals more particularly with those deposits of hydrocarbons which have resulted from underground circu- lation. As it is proposed to emphasize the fact of circulation, those substances which are more readily transferable will be especially considered. These are natural gas and petroleum, or, as they are more commonly termed, gas and oil. The physico-chemical relations of gas and oil to the other hydro- carbons should not be forgotten, and it is not intended here to consider them as separate classes of deposits, as has been too commonly done.

The following brief statements are given as a summary of the points upon which writers are quite generally agreed :

1. The source of gas and oil is the organic matter which was deposited in the sedimentary formations.

2. The manner in which they are formed is perhaps only vaguely understood, but is commonly stated to be a process of decomposition and distillation.

For their existence in economic quantities the following con- ditions are essential :

1. A formation which, because of its more or less porous nature, will serve as a conductor and reservoir, and which is favorably located with respect to the source of supply.

2. Structure which is favorable to their accumulation.

3. An impervious cover which will hold them in.

The reservoirs are rocks, such as sandstones and limestones, which have fracture-spaces or open texture. The cover is commonly a shale. A favorable structure is an anticline or upward arching of the formation. Arrested anticlines and terraces are the less symmetrical forms of this structure.

Accumulation within the reservoir proceeds in accordance with hydrostatic laws, and the oil and gas arrange themselves in the openings in the rocks in accordance with their specific gravities. Since oil and gas are lighter than water, when they are present in a permeable stratum, the oil and gas will be dis- placed upward.

There are two causes of the pressure of oil and gas in the rocks : the hydrostatic force exerted upon them by circulating water, and the expansive power of the gas present.

While the above summary may appear to be an adequate statement of facts, a knowledge of which is essential to the

Gbologic Dbposition Of The Htdrocarbons. 343

exploitation of the deposits, it is far from being a satisfactory explanation of the origin of the deposits. On the chemical side it has been demonstrated that the hydrocarbons are deriv- able from organic matter. The chemical changes which they may undergo within the earth have, however, not been care- fully studied. The more general physical laws have been accepted as controlling their accumulation, but the processes have been neglected. There are, moreover, physico-chemical problems which are more elusive and difficult.

From the principles which are considered as controlling the deposition of ores, certain corollaries may be drawn which are applicable to the hydrocarbons. They are as follows :

1. Oil and gas and the related hydrocarbons are derived from matter originally deposited by the processes of sedimen- tation within the sedimentary rocks.

2. Their concentration as economic deposits is the result of circulation.

3. In their movements they have been influenced chiefly by gravity.

4. Other factors which influence their movement are tem- perature and pressure.

6. Their movements have been through capillary and super- capillary openings, but principally through capillary openings.

6. During their movement through the rocks they have been in intimate relation with underground water.

7. Water, in its circulation, issues at a lower level than its intake. The tendency of oil and gas is apparently to issue at a higher level than its source of origin.

In explaining the origin of ore-deposits it has been shown that the metals are carried in solution by underground water. The solubility or miscibility of the hydrocarbons in water has not been a subject of special research. If the sedimentary rocks were deprived of their water contents, the gaseous hy- drocarbons would readily escape to the surface unless held by the structure of the rocks. The liquid hydrocarbons would follow a path similar to that which water does. Water, how- ever, may be considered as always present. Very little is known concerning the relation of the hydrocarbons to water within the earth's crust. In the case of the transfer of the metals they are in solution in the circulating water; in the

344 Gbologic Deposition Of The Hydrocarbons.

case of tke transfer of the hydrocarbons, the relation is one of mechanical mixture and, to some extent, solution. Oil and water are commonly regarded as not miscible ; but there is reason to believe that, with the varying conditions of temperar ture and pressure, solution of certain of the hydrocarbons takes place ; and, if it occurs only to a limited extent, it is a potent factor in their transfer. Where the relation is one of mechanical mixture (or where, as in accordance with the popu- lar notion, the hydrocarbons float upon or are suspended in the water), the movement of the hydrocarbons, where water is descending, would be in the reverse direction from that of water. K solution takes place, or if the hydrocarbons are in any degree miscible, their movement will be with the water.

The deposits of hydrocarbons which are found within the same geologic horizon vary in composition with the locality. It is not improbable that they may have been derived from the same broadly disseminated organic matter. In accounting for the difference in their composition, we may appeal to the vicis- situdes which they have undergone since their formation. The heavier and lighter hydrocarbons are readily separable in the laboratory. It remains for us to discover what processes effect this separation within the earth. Factors which may there be appealed to are differences of temperature and pressure, which will effect the solution of the hydrocarbons in water and of heavier hydrocarbons in the lighter ones.

As helpful to an understanding of the origin of deposits of oil and gas, we may discuss the geologic conditions which maintain in the Cretaceous formations outcropping in the foot- hills of the Rocky mountains in Colorado, and, extending east- ward under the Plains region, are found again outcropping in central Kansas. The shales contain notable amounts of dis- seminated hydrocarbons wherever they have been seen in out- crops or have been reached by deep borings. Economic de- posits of oil and gas, however, have thus far been found only at a few localities; — for example, the recently-discovered field at Boulder, Colorado. In the series of Cretaceous rocks is the porous Dakota sandstone, which is a well-known water-bearing horizon, and which has been extensively studied, since it is a source of artesian flows. It is generally stated that the water enters this formation at the foothills and finds issuance in the

eBOLOGIC DBPOBITION OF THE HTDROGARBONS. 845

Plains region. The circulation of underground water, which takes place to a much more limited extent within the less porous formations which contain hydrocarbons, obeys the same general law. Accepting, now, the statement that the hydro- carbons are not miscible or soluble in water, the effect of the movement of underground water under hydrostatic pressure would be to cause the oil and gas to be displaced upward, i.e., to ascend along the strata, toward the foothills. They would eventually find issuance, unless held at some intermediate point where the structure is such as to arrest their progress. If, on the other hand, the hydrocarbons are in any degree miscible with water, or are soluble in it, we should expect that the movement of the water from the foothills to the plains would carry certain of the hydrocarbons with it ; also, that they would find issuance with the water through springs and fissures, or be accumulated at intermediate points.

As a third possible condition, certain of the hydrocarbons may be displaced upward against the flow of water, while others may be carried with it Under these circumstances the conditions of circulation would result in the separation of the various hydrocarbons into distinct reservoirs, and subse- quently, with changed conditions, the transfer of certain of the hydrocarbons from the reservoirs in which they had accumu- lated. As an example of the last condition, we may suppose a reservoir of hydrocarbons accumulated under an anticline through gravitative movement. If, for any reason, the tempera- ture or pressure is changed, the power of water to dissolve cer- tain fractions might be increased. The long-continued move- ment of water and hydrocarbons in contact would thus result in the transfer of these fractions, and the composition of the contents of the reservoir would be accordingly changed.

I desire here to call attention to a form of underground reser- voir such as is found to contain oil and gas in some fields. This form of reservoir has not been sufficiently described or sufficiently emphasized, although it has been recognized by some writers. Usually, anticlinal structure is considered essen- tial to the formation of a reservoir. The upper marginal por- tion of a sealed-in porous stratum, however, answers all the re- quirements for holding the hydrocarbons. If the bed is inclined, liie hydrocarbons will irravitate upward. In case the bed is

346 Geologic Dbposition Of The Hydrocarbons,

discontinuous before reaching the surface, or changes in char- acter so that it is not porous, the oil and gas will be held as efficiently as under an anticline, provided that the adjacent strata are impervious. Reservoirs of this type apparently occur in the Kansas-Indian Territory field, and at Corsicana, Texas.

Asphalt bodies occurring in fissures are a class of deposits quite distinct from the hydrocarbons found within the rocks. They are considered as being derived from the more liquid hydrocarbons through oxidation and the loss of the volatile fractions. I desire to speak of them here in order to call attention to certain conditions which obtain in their accumu- lation. Fissures are the result of the fracturing of a rock- mass, but they may widen and be extended gradually. It seems to me more reasonable, in most instances, to suppose that the asphalt may have accumulated gradually, and with the de- velopment of a fissure. The hydrocarbons, in a stratum which supplies the material to fill a fissure, follow the laws controlling circulation through rocks until they find issuance into the fis- sure. On entering the fissure the material is in a semi-fluid form, and in the presence of water will rise in the fissure. If water were not present, it would not rise above the level of the supplying stratum, since there would be no hydrostatic force actuating its flow. The process of solidification is probably slow, and may or may not keep pace with the supply. Obvi- ously, the process of oxidation may vary with the conditions of filling of the fissure and with the circulation of water in the rocks adjacent to the mass. Where the asphaltic material is not brought into the presence of atmospheric oxygen, oxidation is effected through the agency of the ground-water. The loss of the lighter hydrocarbons from the mass must take place by transfer through water. Here pressure and temperature are important factors. Accordingly, we may appeal to the same causes in accounting for the differences in composition of the asphalt as in the case of the petroleums. After solidification of the asphalt has occurred in a fissure, it may be subjected to stress like any rock. The adjustment of stresses and strains is evidenced in the structure of the asphalt veins. Such ac- commodation may possibly be attended with changes in com- position.

There is a popular notion that asphalt in veins is the result

Amarillium. 847

of intrusion, i.e. that it has been forced into fissures in some such manner as igneous intrusions are formed. This idea, however, cannot be supported, since the material, before it finds issuance into the fissures, exists within the pores and cavities of the rocks, and is not subject to stresses other than the hydrostatic pressure acting upon it. Stress in the rocks which would be capable of expelling the hydrocarbons from the pores or cavities would necessarily be great enough to de- form the rock, and such a force cannot be appealed to in the fields where asphalt deposits occur.

In conclusion, I desire to call attention to the fact that in filtering oils through fuller's earth, the separation of the lighter oil from the heavier is obtained in a manner somewhat similar to. that accomplished by fractional distillation. It is possible that in the underground circulation of the hydrocarbons the structure of the rocks through which they pass may be an im- portant cause of variation in composition. Attention has been called to this fact by Dr. David T. Day in a paper read by him before the First International Petroleum Congress in Paris.

Amarillium.

BT WILLIAM M. COURTIS, DETROIT, MIGHIQAN. (New Haven Meeting, October, 1902.)

While assaying some copper carbonate ore from the Prazer claims, Similakameen, B. C, I noticed that on parting the gold button a deep orange solution was formed. The button gave off pink bands in the nitric acid, which became deep orange at a short distance from it; and as it traveled over the surface of the porcelain dish, it left a deep orange track behind. As the button brightened in the cupel, it appeared to have a bronze color; but I have since found that when amarillium is in large excess of the gold, the button is a very dark gray. The button parted easily. To the orange solution I added a salt (NaCl) solution, shook in a silver test- bottle, and filtered. With H,S I obtained a precipitate, which I supposed due to platinum. However, on further tests, it did

848 Amarillium.

not act like a platinum-precipitate, but fused and united some- what with the surface of the porcelain cup. On testing it fur- ther with soda I obtained a button of metal (amarillium). This strange result led me to a careful examination of the ore and a repetition of the assays, remembering the highly em- phatic instructions of my talented instructor in assaying, the late Professor Fritzsche, of the Royal School of Mines, Saxony.

The ore is a friable copper carbonate, containing quite a large quantity of magnetic iron. It is probably an altered, micace- ous, igneous rock, impregnated with decomposed chalcopyrite. This ore carries 1.4 ozs. of gold, 2 ozs. of silver and 3 ozs. of amarillium to the ton ; so that at first, as I had only 1 oz. of the ore to work with, I had but 3 milligrams of amarillium with which to make all my determinations. I then secured 8 lbs. of the ore, from which I obtained about 160 milligrams of amarillium ; but through an accident this was all lost except 14 milligrams, on which the following tests have been made. They were made September 27, 1901, and the results I commu- nicated to Dr. Drown, of Lehigh TIniversity, Bethlehem, Pa., and to Prof. Pettee, of the University of Michigan, Ann Arbor, Mich.

I prepared the ore by dissolving out the copper in strong nitric acid, and, after the first action was over, boiled the solu- tion low, diluted with a large amount of hot water, and filtered. I added salt (NaCl) solution to the filtrate and filtered a second time. I then burnt the two filter papers together and smelted the residue in crucibles, as I would any oxidized ore. The metal in this ore was reported by eastern assayers as platinum and palladium ; but, as can be seen from the tests, it shows, also, many characteristics of cobalt and nickel, and appears like a link between these two groups.

My tests gave results as follows : At times the button ap- peared malleable, at others very brittle, so that I thought it might have taken up, in the course of the work, some im- purity like sulphur or carbon. In the brittle state it cuts steel. It is magnetic, and, as near as I could tell from a 10- milligram button, considering the plus and minus errors, its specific gravity is 8.2. It cupels out with the precious metals, but, when alone, goes into the cupel. Also, when alone, it goes into the slag in a crucible assay. It is easily reduced with soda

Amarillium. 349

by the blow-pipe ; it melts into a button, but not readily, and much of it is in the form of spangles, which, however, can be collected in a button by continuing the blowing. This button gives off a white coating on the charcoal, which burns away with a bluish flame. In a borax bead, in the oxidizing flame, a small bit of the metal gives off brown streaks as it oxidizes, and finally makes the bead enamel white and opaque. In the reducing flame the bead becomes clear and has a deep cobalt blue color, but when held in the gas-light the shade of blue looks somewhat different from that of cobalt. The borax bead, reduced by tin, gives a black or dark blue color. In salt of phosphorus, in the oxidizing flame, the bead is blue, lighter than the borax bead, and in the reducing flame is crimson-lake. Of course it is possible that my button was not pure, but was alloyed with other metals, traces of copper, silver and lead being probable. In the main, these reactions are manifested in all my testing.

On examination of the ore, I found that the mineral from which this metal came occurred in arrow-head points, probably as sulphide. It is insoluble in boiling nitric acid, but soluble in Aqua Regiay and on heating the concentrates, sulphur is given off. As nearly as I could determine from the quantity I had, the ore appeared like sperrylite. I called it courtisite. I then carried the solution from the button through all the usual tests of qualitative analysis. I could not determine the valence of the metal, as the button seemed to have taken up carbon and left a black skeleton, which was not gold. The chemical examination shows that the metal is thrown down by HS in an acid solution, and that the sulphide so obtained is soluble in sodium or ammonium sulphide, from which it is pre- cipitated by boiling, or by making the solution acid. The ammonium-sulphide solution looks like a solution of nickel. Ammonia gave a cloudy precipitate (not examined). In its other reactions the meta.1 seems to follow platinum, precipitat- ing on zinc, and starting a strong ebullition in a weak acid solution with zinc. There is no cobalt in it, for on dissolving in nitric acid, evaporating to dryness and taking up with hy- drochloric acid, the solution still remains deep yellow.

I had not intended to publish these results at present, as I have sent to the mine for 500 lbs. of the ore on which to vol*, xxxni.— 22

850 Orb-Dbposits Of San Pedro District, Nbw Mexico.

make more thorough tests, but the recent discovery of what is called " josephinite," from Josephine county, Oregon, led me to believe that amarillium had been found in quantity, as the account I read described the metal as lying between platinum and nickel. I, therefore, decided to give these results as an aid to anyone in making their determinations, and establish, if I could, the fact that I had really first discovered this metal, should that reported by others prove to be identical with mine. So far this summer I have had only 9 lbs. of ore from the mine. It was a hard ore, and seemed to carry only small traces of amarillium or gold, not being the same kind as that sent before. I expect to receive a large amount of the ore, and to fur- nish later results in a more carefully prepared paper.

The Ore-Deposits of the San Pedro District, New Mexico.

Bt Morrison B. Yunq And Richard S. Mooaffery, San Pedro, New Mexico.

(New Haven Meeting, October, 1902.)

In the southern part of Santa Fe county, New Mexico, there are three groups of mountains, each of which penetrates the Carboniferous and Cretaceous sedimentary strata as a unit, and presents, in the main, the same characteristics and appear- ance. , They extend in a north and south line, and, in order from the north, are the Ortiz, the Tuertos and the South moun- tains. The region has long been known for its mineral wealth.

The mountains present one of the features which first at- tract attention as one approaches the district over the plains from the east. They resemble each other so closely in appear- ance and height that the question naturally arises. Are not the three in some way related geologically ? To the north is the Ortiz group, a cluster of sharp cone-like peaks, formed by the breaking of the eruptive syenite-porphyry through the flat beds of limestone and sandstone of the Carboniferous and Cretaceous age. These beds have been slightly lifted by the intrusion, and slope away from the mountains with a gentle and even dip. Four miles to the south is the Tuerto or San Pedro group, the geology of the western portion of which is the one

Exico. 351

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Orb-Deposits Of Sa1< Pbdro District, New Mexico. 851

exception to the rule of this trio. This western part consists of San Pedro mountain proper, the greater part of which is formed of tilted sedimentary beds ; but the eastern part of the group, including Oroquai mountain, consists entirely of the eruptive syenite-porphyry, with its sharp topography similar to the Ortiz group. Again, 3 miles farther south, is South mountain, which really includes several peaks and numerous spurs. This is also formed by an intrusion of syenite-por- phyry, and shows the same topography as the first two groups. Some miles north of the Ortiz mountains, but beyond the area of eruptives, is situated the colliery-town of Madrid, where the Colorado Fuel and Iron Co. is working beds of both bituminous and anthracite coal. In the foothills north- east of the Ortiz mountains is the ancient mining village of Dolores. On the west side of the Tuerto group is Golden, a small adobe town inhabited mostly by Mexicans, who work in the neighboring mines or who dry-wash the placers in the vicinity. About 2 miles south of Golden is San Pedro, built up chiefly by the development of the copper properties there- about. Although the region has been known for a very long time, there are only a few mines which have reached any considerable development in their underground workings, so that in many cases the interpretation of the geological phe- nomena of the ore-deposits is dilficult.

General Geologt.

The general geology of the region is outlined on the accom- panying map. Fig. 1, the topography being from the San Pedro sheet of the U. S. Geological Survey.

These mountains, rising from the nearly flat sedimentary plain, are formed of an eruptive rock containing both ortho- clase and plagioclase feldspars. These feldspars vary in tex- ture from porphyritic on the outskirts to granitic at the core of the igneous mass. Syenite-porphyry is the name probably best suited to it. Each group of mountains was once an enormous laccolith, but the sedimentary strata both above and around the intruded masses have been entirely eroded, so that now, with the exception of the western end of the Tuertos, there remains nothing but the igneous rock. From the

352 Orb-Beposits Of San Pedro District, New Mexico.

physical characteristics of these eruptive rocks it is evident that they are not surface flows, hut are intrusions into the sedimentary heds. Erosion, amounting to at least 2000 ft., has gone on quite rapidly, as is shown by the present condi- tions, in which the soft sandstone beds of the surrounding plains are being trenched by deep arroyos. Just how near these intruded syenite-porphyries came to the surfece it is impossible to tell, since the specimens taken from the present peaks show scarcely any diflference, in the conditions of cooling, from those taken at points which must have been deep below the original surface.

Fig. 2 is a photograph of the three mountain groups taken from the eastern plains, and immediately below it is an ideal section through them. The region to the west of these groups extends for several miles in a gradually descending plain, which is cut by arroyos of various sizes from 6 ft. to 100 ft. in depth, and with precipitous sides. These all merge into a large central basin of a mile in width. Both in the tributary arroyos and in the central basin is a fine exposi- tion of the beds composing the plain. These beds are chiefly pure sandstone, and are cut in several places by large dikes of andesite, which seem to extend toward the Ortiz mountains, although it is impossible actually to trace them thus far, as they are lost under the surface.

There are also, in the central basin, several peculiar hills composed of sandstone beds, with an igneous cap which lies conformably on the sedimentary strata, and which is responsi- ble for the prominence of the hills. Their relative positions are such as to show, beyond a doubt, that they were once a con- tinuous sheet, which, by faulting and erosion, has attained its present form. They face the west with abrupt cliffs of the an- desite cap, below which is a talus that partially conceals the underlying sandstone strata.

The lowest of the beds yet exposed is a hard, shaly, reddish- brown sandstone, known as the " red-beds." Above this, and conformable with it, is a soft yellow sandstone 60 ft. thick; then comes an unconformity, beautifiilly shown in some of the north and south gulches. After the unconformity a soft red sandstone follows, above which is a soft conglomerate bed, 10 to 12 ft. thick, which seems to be a cemented placer-deposit

Orb-Deposits Of San Pedro District, New Mexico. 353

k;

Si

'1

854 Ore-Deposits Of San Pedro District, New Mexico.

The constituents of this last vary in size from small pebbles tO' boulders a foot in diameter, and represent all the varieties of rock found in the neighboring mountains. Particular interest is attached to this bed on account of the values in gold which it carries. Unfortunately, these are not uniformly dis- tributed, a condition which is necessary for the successful working of such a low-grade deposit. The gold-value varies all the way up to per ton. Several companies are now testing these beds for a successful economic treatment of them, and one has erected a thirty-stamp mill.

A very interesting feature of the general geology of this region is a line of hills lying to the west of the San Pedro- and South mountain groups, and extending in a northeasterly direction. They are composed of a remarkably pure bluish- white quartzite, and probably belong to the Cambrian period ;. at any rate, they are far older than the surrounding strata. These hills extend to the northeast as far as Golden, and, with many breaks, as far southwest as Tijeras canon. Between this range of low hills and South mountain there is a small area of coarse pink granite, bordered in places by a typical mica schist. This pink granite closely resembles the granite forming the axis of the Sandia mountains 12 miles to the west, but no connection between the two has as yet been determined. On the west flanks of the San Pedro and South moun- tains are several hundred feet of Carboniferous limestone which forms the foothills; above this, on South mountain, is a. band of red sandstone which circles the entire mountain. This sandstone belt is not found on the San Pedro group of moun- tains, but a ove the limestone is a complicated series of baked shales and metamorphosed sediments which will be spoken of later. To the south and east of the three groups of mountains a flat plain of Cretaceous shales and sandstones extends for many miles. The northern portion of this plain contains con- siderable coal, and is cut by andesite dikes which seem to emanate from the Ortiz mountains. Some of these dikes are large and of very striking appearance. They rise out of the flat plain for 100 to 250 ft., and extend across the country like huge barriers. Many of them are covered with old Indiaa hieroglyphics.

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354 Ore-Deposits Of San Pedro District, New Mexico.

The constituents of this last vary in size from small pebbles te- boulders a foot in diameter, and represent all the varieties of rock found in the neighboring mountains. Particular interest is attached to this bed on account of the values in gold which it carries. Unfortunately, these are not uniformly dis- tributed, a condition which is necessary for the successful working of such a low-grade deposit. The gold-value varies all the way up to J2 per ton. Several companies are now testing these beds for a successful economic treatment of them, and one has erected a thirty-stamp mill.

A very interesting feature of the general geology of this region is a line of hills lying to the west of the San Pedra and South mountain groups, and extending in a northeasterly direction. They are composed of a remarkably pure bluish- white quartzite, and probably belong to the Cambrian period ; at any rate, they are far older than the surrounding strata These hills extend to the northeast as far as Golden, and, with many breaks, as far southwest as Tijeras canon. Between this range of low hills and South mountain there is a small area of coarse pink granite, bordered in places by a typical mica schist. This pink granite closely resembles the granite forming the axis of the Sandia mountains 12 miles to the west, but no connection between the two has as yet been determined. On the west flanks of the San Pedro and South moun- tains are several hundred feet of Carboniferous limestone,, which forms the foothills; above this, on South mountain, is a band of red sandstone which circles the entire mountain. This sandstone belt is not found on the San Pedro group of moun- tains, but a ove the limestone is a complicated series of baked shales and metamorphosed sediments which will be spoken of later. To the south and east of the three groups of mountains a flat plain of Cretaceous shales and sandstones extends for many miles. The northern portion of this plain contains con- siderable coal, and is cut by andesite dikes which seem to emanate from the Ortiz mountains. Some of these dikes are large and of very striking appearance. They rise out of the flat plain for 100 to 250 ft., and extend across the country like huge barriers. Many of them are covered with old Indian hieroglyphics.

0be-dbp0sit8 of san pbdro district, nbw mexico. 855

Orb-Dbposits.

The ore-deposits may be divided into four classes : (1) Con- tact-deposits of copper; (2) Lead-silver chimneys; (3) Gold- veins; and (4) Gold-placers.

Under the first head come the deposits worked for copper in the immediate neighborhood of San Pedro. As mentioned before, the western portion of the Tuertos is formed of syenite- porphyry with a crown of limestone and shales, which are in- tensely metamorphosed, and which contain the copper-ores. The deposits are of the class recently described by Lindgren* as contact-deposits. The origin of the ore is certainly due to the pneumatolytic action resulting from a very forcible intru- sion of a molten magma from the earth's interior among beds of limestone. Gases and vapors were liberated and caused to penetrate into the cracks and crevices of the superincumbent mass. The limestone has been replaced by massive garnet, which is in some cases 150 ft. thick. In intimate association with this garnet the ore occurs as chalcopy rite ; while its asso- ciated minerals are specular hematite, epidote, vesuvianite, woUastonite, quartz, and calcite. The ore is always accom- panied by garnet, although the garnet does not in all places carry ore. When the garnet carries the ore, the chalcopyrite is disseminated throughout it mass, and appears to be of syn- chronous origin.

Pigs. S and 4 show the way in which the limestones and shales are underlain by the syenite-porphyry and penetrated by many andesite dikes. Closely following the' contact, and but slightly above it, and also closely following the largest andesite dikes, are the mineralized zones where the limestone has been replaced by the garnet and ore. The limestone left in contact with the garnet is always more siliceous than the limestone further removed from the ore-body. A little below the outcrop, the deposit has been enriched by circulating sur- face-waters, but below this zone there is no evidence whatever of any such action ; on the contrary, all the facts strengthen the belief that the deposit is due to the action of gases and vapors.

The intruded syenite-porphyry has entered like a wedge

Trans., xzxL, p. 226, and OenesU of Ore-DeposiUf p. 716.

;v,-,-;t-il

0rb-dbp0sit8 of san pedro district, new mexico. 855

Ore-Deposits.

The ore-deposits may be divided into four classes : (1) Con- tact-deposits of copper; (2) Lead-silver chimneys; (8) Gold- veins ; and (4) Gold-placers.

Under the first head come the deposits worked for copper in the immediate neighborhood of San Pedro. As mentioned before, the western portion of the Tuertos is formed of syenite- porphyry with a crown of limestone and shales, which are in- tensely metamorphosed, and which contain the copper-ores. The deposits are of the class recently described by Lindgren* as contact-deposits. The origin of the ore is certainly due to the pneumatolytic action resulting from a very forcible intru- sion of a molten magma from the earth's interior among beds of limestone. Gases and vapors were liberated and caused to penetrate into the cracks and crevices of the superincumbent mass. The limestone has been replaced by massive garnet, which is in some cases 150 ft. thick. In intimate association with this garnet the ore occurs as chalcopyrite ; while its asso- ciated minerals are specular hematite, epidote, vesuvianite, woUastonite, quartz, and calcite. The ore is always accom- panied by garnet, although the garnet does not in all places carry ore. When the garnet carries the ore, the chalcopyrite is disseminated throughout itfl mass, and appears to be of syn- chronous origin.

Figs. 8 and 4 show the way in which the limestones and shales are underlain by the syenite-porphyry and penetrated by many andesite dikes. Closely following the" contact, and but slightly above it, and also closely following the largest andesite dikes, are the mineralized zones where the limestone has been replaced by the garnet and ore. The limestone left in contact with the garnet is always more siliceous than the limestone further removed from the ore-body. A little below the outcrop, the deposit has been enriched by circulating sur- face-waters, but below this zone there is no evidence whatever of any such action ; on the contrary, all the facts strengthen the belief that the deposit is due to the action of gases and vapors.

The intruded syenite-porphyry has entered like a wedge

Trans. f xxxi., p. 226, and Oenesis of Ore-Deposits, p. 716.

356 Orb-Deposits Of San Pedro District, New Mexico.

m

under the western end of the mountain, tilting the strata about 13 degrees to the east. The stratum in immediate contact with the intrusive is a lime- stone, varying from massive to shaly, and to the action of the syenite-por- phyry on this limestone is due the for- mation of the ores. Above the lime- stone belt is a series of baked shales and calcareous sandstones, all showing the effects of metamorphism. The shales are both white and black; the black variety, owdng to its hardness, forms prominent ridges which run around the hill. The sandstones also show considerable variety ; there is, for example, a clear, hard sandstone com- posed of quartz-grains cemented by siliceous material. Then there is also an impure, fine-grained, calcareous sandstone, in which metamorphic ac- tion on the lime is plainly shown in many places by the formation of gar- net, wollastonite, and other contact minerals. Lastly, there is a very coarse sandstone strongly resembling a granite. These beds are not clearly defined along their outcrops for any great distance, but, in many instances, pinch out and merge into one another.

Just above the limestone belt is an interbedded flow of andesite, which comes across the hill with the general dip of the beds. It is difficult to say just how much effect, if any, this flow has had upon the main ore-body, which lies 160 fl. below it; but it is undoubt- edly responsible for numerous minor ore-bodies which have been opened up along the limestone belt just beneath it.

Orb-Dbposits Of San Pedro District, New Mexico. 357

From the main syenite-porphyry contact on the west of the hill a dike extends to the east and appears at intervals along the crest, where it has been exposed by erosion, thus indicating the presence of the main body of the syenite-porphyry under the entire hill. The fact that a small area of the same syenite- porphyry is exposed at the eastern foot of the hill also bears out this theory.

The ore-body lies in the hill conformably with the strata, and shows the greatest inequality in the distribution of the ore. It has been worked at three different levels, which are separated from each other by lean places, and not by a wall- rock. The ore carries low values in gold and silver. Oxi- dized ores of copper and iron are occasionally found in the deposit There are various other minor contact-deposits on this hill, and, in every case, they occur in a mass of garnet in the vicinity of the contact of the syenite-porphyry with the limestone. They exhibit the same gangue minerals and char- acteristics as the deposits just described.

The second class of ore-deposits, those of lead-silver in lime- stones, has several representatives and has not been very im- portant commercially. They consist of chimneys of ore which swell and pinch along a fractured zone in the limestone, which has become a channel for the circulation of underground waters. The ore consists of galena, sphalerite, alabandite, pyrite, and a small amount of chalcopyrite. There are also present cerus- site, limonite and the oxidized manganese minerals. The best example of this type of deposit is the Lincoln-Lucky mine, which is on such a chute or chimney. The chute follows the dip of the limestone, and is more or less circular in cross- section and about 60 ft. in diameter. The ore was taken out by underhand stoping and hoisted on an incline through the deposit.

Under the third head come the gold-veins, which are, in number, far greater than all the other deposits combined. They may be roughly divided into deposits along crushed and fissured zones, and deposits which fill fissure-veins and are of banded structure. The first occur either in the igneous rock itself or in the sedimentary strata above it and in close proximity to it. The crushed zone usually lies in an almost vertical plane, and the general direction of these zones is east and west; they

358 Orb-Deposits Of San Pedro District, New Mexico.

have no definite walls, but merge into the solid country-rock. The width varies from a single fracture of an eighth of an inch to 5 or 6 ft. Quartz and pyrite have entered the shattered belts and have formed a network of cross veinlets. The gold, which is usually coarse, occurs with these minerals, and occa- sionally furnishes fine specimens of wire- and sheet-gold. The gold-values are contained almost entirely in the cracks and secondary veinlets, while the rock itself is practically barren. Values from 40 cents to 80 cents per ton have been obtained

Fig. 6.

Cross-section of Gold-Vein in Crushed Zone in Syenite-porphyry.

from this rock, but it is probable that these values came from vein-matter clinging to thie rock-particles. The seams and veinlets will average from $80 to $60 per ton, with occasional pockets of richer values. In the oxidized parts of the veins the cracks are filled with soft gouge-matter and the pyrite is changed to the usual oxidized minerals.

There are a great number of these crushed gold-bearing zones, but they are all small, isolated, pockety, and unreliable. In spite of the fact that there has been a great deal of pros- pecting on this class of deposits, and considerable money ex-

Ore-Dbposits Of San Pedro District, New Mexico. 859

pended on miDing and milling plants, no successfal mine has been developed. The aggregate of the gold in these deposits is undoubtedly enormous, an<J they are the source of the gold in the extensive and rich placers of the district; but the gold occurs in such a way in the veins as to make their economic exploitation out of the question. Fig. 5 is the cross-section of the vein in a mine of this class in a crushed or fractured zone in the syenite-porphyry. Its width averages 4 ft., and the de- velopment of the secondary cross-veins is shown. These vary in width from an eighth of an inch to 8 in., and they carry almost the entire gold-values. Pyrite begins to come in at a depth of 100 ft. At the bottom of the shaft, where the rock is harder and the fractured zone less pronounced, the gold- values stop altogether.

Another mine, in the Ortiz mountains, shows considerable variation from this type. The hill in which the ore-bodies lie is composed of a hard, white sandstone, cut by two dikes of porphyry, which come from the main mass of the Ortiz moun- tains. The porphyry shows peculiar concentric discolorations, which are described by the local name " coon-tail porphyry." These dikes strike into the side of the hill, and do not reach the surface on the other side. The hill, especially at its south- ern end, seems to be penetrated by many intrusive sheets and dikes, which are probably offshoots from the two main dikes. The sandstones at the south end of the hill have been thor- oughly shattered and cracked. Decomposition has resulted along these cracks, and has led to the formation of iron oxides and other secondary products, so that the rock looks like a coarse breccia composed of large fragments of sandstone. The southern dike, where it enters the hill, is much shattered and decomposed, and one of the principal mine-openings is at this point. The rock-fragments carry very low values, if any, while the cracks and fissures of all sizes and lengths carry con- siderable gold. At different places in the sandstone, where the shattering ha rendered the rock easily permeable to ore- bearing solutions, rich bodies of ore are found in connection with considerable secondary quartz and oxidized iron salts. Fig. 6 is a cross-section of this deposit.

A neighboring mine closely resembles this deposit, but the igneous contact is probably more deep-seated than at the

360 Orb-Dbposits Of San Pedro District, New Mexico.

former. It has not yet been exposed by erosion, although out- crops of the syenite-porphyry are not far distant. The ore- bearing solutions have risen alon a bed of sandstone that was more porous than the adjacent beds, and the gold was deposited

Fig. 6.

Mineralized Section of Ore- Body. Syenite-porphyry shoot penetrating sand- stone. Cracks in disintegrated portion are filled with iron oxide which carries gold- values.

in a plane parallel to the sedimentary bedding. Fig. 7 is a cross-section through this ore-body.

The second subdivision of the gold-veins embraces the fis- sure-veins with banded structure. This class of deposit, with one exception, is of small importance in the district. Through-

Ore-Deposits Of San Pedro District, New Mexico. 861

out all three groups of mountains are found occasional small veins exhibiting a filling whose minerals are arranged in layers with comb-structure at the center. Quartz and calcite are the principal gangue minerals, and the ore is auriferous pyrite with occasional chalcopyrite. By far the best example of this class of veins is the Ortiz mine, which is a typical fissure-vein 4 to 5 ft. in width in the main mass of the syenite-porphyry. This is probably the oldest lode-mine in the United States, it having been worked by the Indians previous to the coming of the Spaniards.

Under the fourth head come the gold-placers. While the gold-veins are not, as a rule, persistent, pockets in some of them

Fig. 7.

Cross-Bection Showing Gold-bearing Sandstones near Igneous Contact.

have been enormously rich, and in the fan-shaped placers, at the foot of each mountain arroyo is collected the gold brought down by erosion. The placer-grounds extend from the foot of the mountains in all directions for several miles, comprising in all, probably 20 to 30 sq. miles. Certain places, generally at the foot of a valley or opposite a break in the mountains, are richer than others, but all the gravel carries gold in small quanti- ties. The gravel is very coarse at the immediate foot of the mountains, and becomes somewhat finer in the remoter por- tions. It varies from sand to boulders a foot in diameter, and lies from 20 to 30 ft. deep on the bed-rock. During the greater part of the year this material is perfectly dry. The

862 Orb-Deposits Of San Pedro District, New Mbxioo.

gold is mostly very coarse and little water-worn, and in many cases appears in wire and in flat scales, just as it came from the vein. The richest streak is naturally next to the bed-rock ; and, judging from a great number of working-tests, this will run about $1 per cu. yd., while the surface will not average over 30 or 40 cents per cu. yd. K sufficient water could be obtained for washing, or a successful dry-washer be invented to treat the gravel on a large scale, these placers would prove im- mensely profitable. As it is, a great many dry-washers have been tried here with more or less success (generally less), but for one reason or another none have survived, except the small hand-machines used by the Mexicans. In these they first screen the dirt and pass the sittings over a fine inclined screen, through which is blown the air from a small centrifugal fan worked by hand. The air-blast carries the finer particles down the screen, while the heavier grains of gold are retained in shallow riffles on its upper side. The riffles are cleaned from time to time, and the resulting material is dry-panned, the re- sult of the day's work being from 60 to 80 cents. One of these small machines will treat about a cu. yd. a day. Frequently rich strikes are made which will net the workers from f40 to (50 per week.

The authors wish to thank Professor James P. Kemp for the microscopical determination of rock specimens of this region, and are glad to say that their own independent investigations result in conclusions in accord with his views as set forth in his paper, " The R81e of the Igneous Rocks in the Formation of Veins.''*

Trans., xxzi., p. 169, and OenesU of Ort-DepovUsy p. 680.

Thb Beaumont And Othbr Oil-Fiblds Of Tbxas. 868

The Beaumont Oil-Field, with Notes on Other Oil-Fields of the Texas Region.

Br ROBERT T. HILL, WASmNGTON, D. C. (New York and Philadelphia Meeting, Febmary and May, 1902.)*

Introductory.

The successful completion, January 10, 1901, by Capt. A. F. Lucas, of a well, near Beaumont, Texas, whereby an enormous flow, estimated at 75,000 barrels a day, was obtained, opened a new oil-field in the United States, kindled a frenzy of ex- ploitation and speculation, revolutionized the fuel industry of a large region, and brought gain to thousands of people.

Even to-day, it is impossible to cast up the present results or to prognosticate the future influence of this event. It has caused the revival of attention in other localities where oil had been suspected, and exploration for oil throughout the Texas region. It has attracted notice to the mineral resources of the Texas region, and created an interest in the geological conditions of that great State.

This State, which has increased in population and wealth, as recorded by every succeeding census, with leaps and bounds such as are exhibited by no other part of the Union, now stands fifth in population and first in productive wealth jper capita. Its fields, pastures, forests and mines teem with raw material. The whole economic evolution of the State has gravitated toward a focal point, where these products were available for the coming ot the kiln, the machine and the fiactory.

The only drawback to the prosperity of the State was the lack of an economic fuel, inferior coal costing an average of $5.00 per ton at the time of the Beaumont discovery. This

Secret aby' 8 Note. — This paper was prepared for the Franklin Institute, and presented at a joint session of the Mining and Metallurgical Section of that Society with this Institute, held May 15, 1902, at the Manufacturers' Gluh, Phil- adelphia.

364 The Beaumont And Other Oil-Fields Of Texas.

prevented the successful operation of any one of the thousands of minor industries upon which other communities ordinarily depend for prosperity. As by a touch of magic, this great fuel- supply burst forth in a single day, thanks to Capt Lucas, who, aided by the wise laws of the railway commission, placed at the fireside of every citizen, at every quarry, clay bank, sand pile, mine and mill, the cheapest and best of fuels.

With these factors in hand, who can even grasp the signifi- cance of the great industrial development which is to take place within that empire during the next decade ? Who can conceive the countless wheels to be set in motion, who can reckon the prospective increase in population, the municipal development, the opening of brickyards, factories, shops and mills ? Never before in history has there been such a culmina- tion ; never again will such opportunities be presented for the man of energy and means as are now presented in Texas.

The Limitations of Geological Interpretation of Oil- Phenomena.

In endeavoring to interpret the geological occurrence of oil, the geologist is confronted by the fact that science has not yet solved the problem of fts origin, which lies at the root of the subject.

Among the theories in this field are those of inorganic chemical origin, resulting from reaction of one mineral upon another ; the generation of oil in living microscopic organisms, such as diatoms ; and the generation of oil from the decomposi- tion and deterioration of dead organic matter, animal or vege- tal, preserved in the rocks. There are facts in nature which can be made to conform to any one of these theories ; but for the present we must consider oil as a material in the rocks, the origin of which is still unexplained.

Concerning this occurrence, we can only say that each field where it is discovered presents a peculiar group of data, some of which may, or may not, be presented in others. It is well- known that certain strata, like shales, with large admixture of organic matter, are nearly always more or less bituminous, and are probably the locus of the original formation of oil from de- composition of the organic matter. On the other hand, the oil in commercial quantities is usually found in some adjacent bed,

The Beaumont And Other Oil-Fields Of Texas. 365

like an overlying stratum of sand, which forms a more porous receptacle. Where such shales and sands are in proximity, the oil is practically indigenous; and such occurrences may be termed sheet-oil. In other cases, oil is found in pockets, in strata which do not contain sufficient bituminous matter to jus- tify the reference of its origin to them. Such occurrences may be termed pocket-oil.

Science has ascertained much concerning the underground circulation of water, but we know very little concerning the laws controlling the underground circulation of oil. The few elementary physical facts concerning the behavior of oil and water teach us some lessons. Prom the antithetic behavior of the water and the oil upon the surface, we can with safety presume that these substances will not act in an entirely harmonious manner underground. We know that oil will float upon water, and therefore that circulating underground waters, if ascending, may gather oil from places of its origin, and transport it and store it in remote underground reservoirs. On the other hand, oil differs from water in capacity for permeation and osmosis. Oil stored in a tightly-sealed bottle will pass by osmosis through the glass more rapidly than water. The question of the under- ground migration of oil is one of the profound fields for future research.

The principal deductions from the world's experience con- cerning the occurrence of oil are :

1. The chemical origin of oil is as yet unexplained.

2. Oil may occur in stratified rocks of any age from the old- est Paleozoic (as in Pennsylvania) to the latest Tertiary (as in Texas).

8. Oil usually occurs in terrigenous (land-derived) marine deposits, such as sands and clays, in which there is a mixture of organic matter, and is not common in rocks of deeper-sea origin, such as many of the foraminiferal limestones, or igneous rocks.

4. The circulation of oil in rocks is different from that of water.

5. The structure or arrangement of the rocks influences the collection and storage of oil ; and hence the knowledge of ge- ological structure aids in the determination of favorable or un- favorable conditions for the underground storage of oil.

866 Thb Beaumont And Othbb Oil-Fields Of Texas.

6. Some underground bodies of oil are known to be stored in, or even to be derived from, definite strata. The trained geologist can indicate the underground extent (" embed ") of such strata.

7. Other underground oils are stored in favorable loci more or less remote from the strata in which they originated, and accumulated in folds or pockets, like water in a rubber blanket (the blanket being inverted).

The above facts indicate what the geologist can and cannot tell concerning oil-fields. The first thing he can do in the great region is to eliminate or cancel broad areas of unfavorable strata, leaving certains fields of probability and improbability. Within a determined field of probability it is impossible to predict the actual point where oil can be found. The cost and credit of developing the oil-field must always ultimately fell upon those who boldly risk labor and money upon what is largely a game of chance.

The practical geologist has to deal primarily with the strata igraphic location of oil ; the deformations of strata favoring the collection of this oil in geological receptacles ; and the laws of underground circulation of oil in the rocks.

Where a determined oil-field is underlaid by sheet-oil, the probabilities of success are greater, and the geologist can assist the practical man with some confidence. On the other hand, where the oil-field consists of pockets, no one knows as yet how to locate these pockets beneath the surface.

The oil-bearing strata of the Beaumont oils are entirely dif- ferent from those of the Oorsicana oil-field (where the oils are derived from the Upper Cretaceous strata) ; from the Indian Territory oil-fields (where the oils are derived from the Carbon- iferous strata) ; and from the oil-fields of Pennsylvania, Ohio and West Virginia (which receive their oil from the still older Paleozoic rocks, such as the Trenton).

The prospector in the Beaumont oil-field must be prepared to cast aside previous conceptions based upon the structure and age of the earlier-known oil-fields.

Geography of the Texas Region. In a recent paper* the author presented an outline of the physiographic features of the Texas region, as shown on a map

Topog. Atlas of the U, S,, Folio 3 ; Phys, Gecg. of the Texas Begion, U. & O. &,

The Beaumont And Other Oil-Fields Of Texa8.

therewith, and defined its earliest primary natural subdivisions, as a basis for more detailed discussion and differentiation of the various phenomena.

The Greater Texas region includes, practically, all the country

Fig. 1.

Brown Wood Field

Corsicana Field

Nacogdoches Field

Beaumont Field

Trans-Pecos Field

OIL WELLS OPOSSIBLEOIL H-OlLSIPES ASPHALTUM

Map of the Texas Oil-Region and adjacent OU-bearing Territory.

east of the Rio Grande and south of the northern boundary of New Mexico. The area thus defined consists of a peculiar group of physiographic units, composed of mountains and plains belonging to the four greater natural provinces of the United States, to wit: the Cordilleran region, the Great Plain region, VOL. xxxin.— 23

368 Thb Bbaumont And Othbr Oil-Fiblds Of Tbxas.

the Appalachian region, and the Atlantic Coastal Plain. The characteristic features of these regions as they extend into the State present local modifications. There are also in the central portion extensive stretches of country which have no counter- part elsewhere.

It is impossible to give here the details of the varied geo- graphical features of this vast area, which includes nearly one- tenth (Texas proper embracing one-twelfth) of the present area of the United States. In another paper* I showed the rapid evolution which the economic features of Texas have undergone in the past twenty years from the pastoral to the industrial con- ditions, and declared that the one great need of the State was an economic fiiel. Almost coincident with the publication of that paper was the completion of the great oil-wells at Beau- mont.

The already ascertained oil-yielding territory of the State with its probable extension into adjacent States is indicated on accompanying sketch map. Fig. 1.

Sedimentary Rocks of the Texas Region Connected with THE Oil-Problem.

Most of the surface of Texas is formed of sedimentary rocks, igneous formations covering a smaller area. There are also extensive formations composed of wind-blown dSbriSy chemical precipitates, and upland drift.

The sedimentary rocks are alone pertinent to the present paper. They lie one above another in more or less orderly succession, and are of two general classes : (1) marine forma- tions, originally laid down upon the marginal bottoms of the sea ; (2) superficial formations, deposited upon the slopes of the land or at local deposition-levels, such as lakes, rivers or other bodies of water within the land-area.

The marine sedimentary rocks laid down on the searbottoms are of all ages from Cambrian to Recent, with the possible ex- ception of the Devonian. They aggregate about 25,000 feet in I thickness, as shown in the vertical section. Fig. 2. The strata vary in hardness ; are tilted steeply in the mountainous areas,

See Forum, Augost, 1900, and Encydopaodia Britannica, London Times SappU- maU, 1902.

Fig. 2.

a o

Uj

s!

O ui o

(A

O

cr u

o

UpfMf

Lower TriM?

Ptrmian

Ordovician

Cambrian

Algonkian Archean

u e!

mi

Oockum

Montana

Colorado OakoU

Washita

Pradoriokabuig

Double Mountain

Clear Fork

Wichita

Coletnan

Waldrip Brownwood

Richland

Bend

Section showing the geology of the Texas region.

370 THE BEAUMONT AND OTHER OtL-FIELDS OF TEXAS.

and are nearly horizontal in the plains. They are of two general classes, differing in occurrence and importance :

1. An older or fundamental series of Paleozoic formations. The structural arrangement of these formations in anticlines and synclines is discordant with that of the later formations of the Coastward Slope. The series represents the remains of an an- cient topography, which was base-leveled during Jurassic and Cretaceous time, prior to the invasion of the Cretaceous seas, which completely buried it with later sediments. These older rocks, except in the mountains, are now seen only where areas of the later strata have been worn away. In the structure of this group is written an interesting pre-Cretaceous history, in- volving the growth and decay of relief-features quite different in detail from those of the present time.

2. Formations of the Coastward Slope from Cretaceous to Recent age. Most of these rocks were once marginal deposits of the Gulf of Mexico, laid down when it extended much far- ther inland than it does to-day ; and they were elevated as the Gulf receded from the Rocky Mountain front to its present position. All these strata now incline toward the sea. In some instances the inclination coincides with the surface-slope, while in others it is slightly greater.

The Paleozoic rocks may be divided into two groups — the earlier and the later Paleozoic. The first includes the Cam- brian and Ordovician ; the second, the Carboniferous and Per- mian, or Permo-Triassic. The same names characterize four primary lithologic subdivisions. Of these, the first two are usually more or less associated in geographic occurrence in limited areas, and by reason of their hardness produce allied features of topographic relief. The third and fourth, forming the surfaces of large areas, have each individual features.

The pre-Cambrian and older Paleozoic rocks are the founda- tions upon which all the other rocks were laid down, and are still, in the main, covered by them. Their outcrops are ex- ceptional and restricted in area; they occur in small districts in the Wichita range of the Ouachita mountain system, in some of the trans-Pecos mountains, especially between the and 82d parallels, and in a limited territory in the southern end of the Central Province, known as the Burnet country.

The Cambro-Silurian rocks are indurated clays, sandstones,

Thb Beaumont And Othbr Oil-Fields Of Texas. 871

and limestones. They usually occur in geographic association with the pre-Cambrian and Carboniferous rocks, in the south- ern part of the Indian Territory and central Texas.

The Carboniferous rocks are the chief formations of the Ouachita mountains, the eastern border of the Central Prov- ince in Indian Territory and Texas, and certain mountains of trans-Pecos, Texas. The Permian, or Red Beds, prevail in the greater part of the Central Province and in the Pecos and Canadian valleys. The Carboniferous and Permian rocks pro- duce somewhat allied but difterent topographic forms. The Carboniferous (east of the Pecos), largely made up of soft, im- pure shales, alternating with harder, coarse brown sandstones and conglomerates, produces ridge-like mountains and a broken belt of country along the eastern margin of the Central Prov- ince, called " flats." The Permian Red Beds, some 7000 ft. in thickness, consist largely of unindurated arenaceous clays, with only a few hard strata. They weather into extensive flat re- gions with occasional scarp-lines attended by " bad-land " slopes. They occupy the western and greater part of the Cen- tral Province, extend beneath the Plateau of the Plains, and outcrop in Pecos valley against the eastern front of the Cor- dilleras.

The existence of the early Mesozoic (Triassic) is doubtful, although possible. Rocks referred to this period overlie the Permian along the western part of the Central Province, and appear in small areas around the border of the Plateau of the Plains, but are not pertinent to our present subject. Jurassic limestone strata of the Mexican type have been found in only a limited area in the basin-ranges of the interior desert, west of the Cordilleran front, and are not known on the Atlantic slope or in the series of the Texas Coastal Plain.

The Coastward Gulf slope consists of vast sheets of sea- made sediments, from Cretaceous to Pleistocene age, inclusive, and of aggradational deposits of upland wash, and stream and lacustral alluvium of Tertiary and later age, all of which, ex- cept the Lower Cretaceous, are mostly unconsolidated terranes of clay, sand, marl, and loam. Of this later group, the marine Cretaceous, Tertiary and Pleistocene rocks are the chief forma- tions, especially east and south of the Central Province. These rocks occur in belts sub-parallel to the coast.

372 The Beaumont And Other Oil-Fields Of Texas.

The Cretaceous rocks are divisible into an older or lower and a newer or upper series. They occur along the western border of the Coastward Slope plain. The older formations consist of hard limestones alternating with clays, and are underlaid by sands ; they produce dip plains, cut plains, and low scarps. The Upper Cretaceous strata consist largely of unindurated clay marls, with a few indurated scarp-making strata all under- laid by sands, and weathering into low, undulating areas.

These Cretaceous strata, underlying the Coastal Plain of Texas, in the Black and Grand Prairie countries, have been minutely described by the writer in many papers, especially Part Vil. of the Twenty-first Annual Report of the Director of the United States Geological Survey. These consist of nearly four thousand feet of shales and sands, and limestones; probably one-half of the section is made up of marine near- shore clays and sands, and the remainder of deeper water lime- stones. The Cretaceous strata constitute the floor or founda- tion upon which the Tertiary and Pleistocene sediments were deposited, and most probably underlie the whole Coastal Plain of Texas, at great depth, their base being not less than 10,000 feet deep along the coast at Galveston.

For present purposes the Tertiary may be divided into two great groups, a lower and an upper, which may be termed the Eocene and Neocene respectively.

The Eocene strata consist of a series of unconsolidated sands and clays, accompanied by fossil shells and beds of lignite and about 3000 ft., more or less, in thickness. They have been considerably studied in a manner to make known their strati- graphy and character ; but the nomenclature and classification are still susceptible of refinement. The writer prefers for the present to divide the rocks of the epoch into two series. For the older, including all the rocks from the base to the Nacog- doches oil-formation, he has already used the name Camden series. For the rocks above the horizon, the term Angelina may be used. While paleontologists are disagreed in their de- terminations, these names are good for tentative use.

The Camden series includes many beds of clays, sand and lignite (underlying the East Texas timber-belt), for which vari- ous names have been proposed.*

See various reports of the Texas Suue Oeologuxd Survey.

Thb Bbaumont And Othbr Oil-Fields Of Texas. 873

The Angelina series, above the so-called marine beds of the Camden series, which are the first classified deposits immedi- ately north of the Beaumont oil-field, have been described by Kennedy, in descending order, as follows :

1. The Lufkin deposits (Tegua), made up chiefly of dark-blue gypseous clays, and gray sands containing quantities of saline matter. These beds also contain lignite, in many places, in beds or deposits of considerable extent.

2. The Fayette sands, made up of soft sandstones, light-col- ored clays, sandy clays, and sands with occasional remains of vegetable life. These deposits approach in texture and mode of occurrence the typical Grand Gulf formations, as described by Hilgard, in Mississippi, and by Hopkins, in Louisiana. The plant- remains, such as palms, etc., are also in close correspondence.

3. The Fleming beds (Frio clays) consist of heavy deposits of clays of various colors, some of them containing concretions of lime, and gray sands. The plant-remains of these sands are chiefly wood, and often occur in large pieces and considerable quantities. The Frio clays are considered Eocene in Kennedy's later publications.

The sections made by Kennedy give the general character and sequence of the formations along a general section from Nacogdoches county to the Gulf.*

The thickness of the later Eocene (Angelina series) sections, as given by Kennedy, aggregates 1407 ft.

Above the Frio clays of supposed Eocene age follows a series of unconsolidated sands and clays of Neocene, Pleistocene and Recent age, which constitute the formations of the Coast Prairie. These will be further discussed on a succeeding page, under the head of the -Beds.

Summarized, the postCarboniferous strata beneath the Cen- tral Plain of Texas, and which by dip should be beneath the Coast Prairie, are as follows :

Pl

Post-Eocene, 1000 to 2,500

Eooene, 3,500

Upper Cretaceous, 2,000

Lower Gretaceoos, 2,000

Total, 10,000

Third Annual Rep. Oeol Surv. , 1891, A Section from Terrell, Kaufman county, to Sabine Pass on the Gulf of Mexico," by Wm. Kennedy, pp. 53, 55, 61, 62, 63.

374 the beaumont and other oil-fields of texas.

Structure of the Sedimentary Rock-Sheets.

In general, the Paleozoic rocks of the northern border of the Ouachita mountains of Indian Territory and the mountains of trans-Pecos, Texas, are greatly tilted as a result of the Appa- lachian revolution. Between the mountains the Paleozoic rocks in Texas occupy a great synclinal basin, dipping westward from their exposed eastern outcrops, and eastward from their exposed western outcrops.

Over this synclinal basin, after a long land-period, the rocks of the coastal-plain, the base of the Cretaceous upward, were laid down unconformably. This unconformity is the most radical structural feature in the whole Texas sequence. It is not necessary for our present purpose to go further into the de- tails of the structure of the Paleozoic rocks.

As a whole, these Cretaceous and Tertiary rock-sheets of the Texas Coastal Plain may be collectively discussed as the systems of the coastward incline, and their structure is very simple ; the strata being characterized by their unconsolidated nature, their regularity of sequence, simplicity of arrangement, and gentle dip coastward.

One who begins at the coast and travels across this region, along any line radial to the coast, will find that, while the sur- face constantly ascends above the level of the sea at a slight gradient, it presents a descending geologic sequence in succes- sive belts of country, each with its peculiar soil, rock, and flora, due to the diiFerences in the rock-sheets of which it is formed. The outcrops of the various strata, owing to their physical and chemical composition, have weathered into diverse characters of country — forest and prairie, broken or level — exactly as the substructure permits.

There are few, if any, breaks in the continuity of deposition of the 10,000 ft. of sediments, of Cretaceous and later age, consti- tuting the coastward incline. One of these apparently occurred at the middle of the Cretaceous, but without any special strati- graphic discordance. Another is supposed to have taken place at the close of the Cretaceous, but is not proved.

According to Kennedy, at the close of the period occupied by the deposition of the last of the marine beds of the Eocene, a break of considerable extent occurred ; and extensive erosion, implying elevation, appears to have taken place prior to the de-

The Bbaumqnt And Other Oil-Fields Of Texas. 375

position of the succeeding deposits. Strong proof of this ero- sion can be seen almost anywhere along the line of contact, where the succeeding denudation has carried off the overlying mantle of sand and gravel of the Angelina series. He says that this want of conformity is everywhere visible, and the clays and ' sands of the Grand Gulf frequently extend in long narrow strips for several miles into the region occupied by the Eocene marine formations, and at other places are found bold headlands made up of the deposits of that age. Kennedy also informs the writer that there is a similar break at the top of the Angelina series.

So far as known, there are no strong folds or basins in the strata of the Coastal Plain, such as exist in the Ohio and Penn- sylvania oil-fields, although there are probably some very low anticlines or swells, which materially bear upon the storage of the oil in reservoirs, or oil-containing strata. In general, the structure of the Coastal Plain is monotonously monoclinal.

The formations of the Coastal Plain are all marginal sedi- ments of the Gulf of Mexico ; and the present tilt coastward may be considered the algebraic sum of several periods of ele- vation and subsidence since the beginning of Cretaceous time, the net result of which is a sinking of over 10,000 ft. at the present coast-line.

It is well known that in the epochs from the Pliocene to the present there have been several movements of elevation and subsidence, during which the shore-line of the Gulf of Mexico migrated back and forth. At times this shore-line was far in- ward from its present site, while at other times it may have been considerably seaward.

It is also probable that the stress resulting from the vertical movements of these strata caused faults, some of which are already known to have taken place along the western margin of the Coastal Plain.

Oil-Fields of the Texas Region.* While the phenomena of the Beaumont field have attracted great attention, many are not aware of the fact that in the State of Texas there are several other oil-fields (productive or pros- pective) entirely distinct from the Beaumont field, and from one

See also JBuUetin U. S. Geological Survey, No. 184, by George I. Adams, Waahington, 1901.

376 The Beaumont And Other Oil-Fields Op Texas.

another, in geological and geographical conditions. One of these has been productive for many years, while the others may some day give profitable returns.

One of these fields is already a large producer of a high-grade illuminating oil, supplying nearly 1,000,000 barrels per year of oil as good as that of the Washington county. Pa., field. There are also many localities where bitumen occurs as asphaltum.

The typical oil and asphaltum horizons of Texas are as fol- lows:

The Beaumont.

Nacogdoches.

CorsicanarSan Antonio (Uvalde asphalt).

The St. Jo (asphalt).

The Brownwood-Henrietta.

The Trans-Pecos.

The Buckhorn (asphalt). Of these, one asphalt-field is found in the Ordovician rocks ; two oil-fields (the Brownwood-Henrietta and the Trans-Pecos) in the older (Carboniferous) rocks of the Coastal Plain ; and the others in the Cretaceous and Tertiary. I shall briefly de- scribe each of these fields in ascending stratigraphic order, which also corresponds to their relative importance.

In the southern Indian Territory there are, in Ordovician and Carboniferous formations, many asphalt springs and bitumin- ous rocks which show the presence of a great amount of bitu- minous material. These asphaltic deposits have been recently described in detail by the United States Geological Survey in a paper entitled " The Asphalt and Bituminous Rock Deposits of the United States," by George H. Eldridge.*

The Pecos Oil-Field. In Reeves, Pecos and El Paso counties, Texas, and in Eddy, Otero and Chaves counties, of southeastern New Mexico, there is a prospective field in which many " seeps " have been found, and oil in small quantities has been struck in wells. This re- gion lies immediately west of the Pecos river, and extends north of the Southern Pacific R. R., far into southern New Mexico, and adjacent to the eastern slope of the Guadaloupe mountain uplift.

See 22d Annual Report of the Director of the U. S. Geological Survey, 1900-1901, Part L, p. 209.

Thb Bbaumont And Other Oil-Fiblds Of Texas. 877

The geological series seems to have, primarily, a great thick- ness of indurated Carboniferous limestones at the base ; then a series of sands and bituminous shales; then another vast thickness of Upper Carboniferous and Permian limestones; then shales and clays of Permian or Triassic age ; then the basement sands and limestones of the Comanche Cretaceous ; the whole being largely obscured toward the Pecos valley by large quantities of wash and desert dSbris. The geological structure consists of a long monoclinal uplift dipping, from the western crest of the Guadaloupe-Sacramento range and the Comanche range, eastward toward the Pecos river. This monocline is waved by numerous secondary anticlines and syn- clines, and steep faults to the west By reason of the ease with which the many low secondary anticlines and synclines can be made out, this structure is apparently more propitious for the location and extraction of oil than that of any other Texaa field.

Most of this area lies upon the eastern slope of the mono- clinal mountains of the Comanche and Guadaloupe-Sacramento range. A few oil-indications have been found further west, in the Salt Basin flat.

Within the area mentioned, oil, asphaltum and sulphur have been encountered at numerous places in wells or springs, and upon the surface ; and while the region has not yet been mi- nutely studied, there is every indication that by scientific study aud exploration it can be developed into an oil-field. Unfor- tunately, the only drawback, up to date, is the fact that the oil thus far encountered is of a very inferior quality, containing, as shown by Prof. Phillips,* a residue of 45 per cent, of as- phaltic material, and only about 25 per cent, of all grades of illuminants.

The Hbnribtta-Brownwood Field.

In this field, coincident with the Carboniferous outcrops in northern central Texas and the southern Indian Territory, numerous finds of oil have been made in small quantities, notably at Henrietta, Clay county, and in Brown and Coleman counties.

These Carboniferous formations are of great thickness (over

BuUeHna Nos, 1 and 2 the Mineral Survey of Textu, Aostin, Tez., 1901, 1902.

378 The Beaumont And Other Oil-Fields Of Texas.

7000 ft. in Texas), and apparently contain many oil-bearing horizons. They also furnish some of the maltha springs of the Chickasaw Nation in the Indian Territory, and the oil and gas of the northern Indian Territory and Kansas. No oil in commercial quantities has as yet been found in this field; but the quality of that hitherto found has been good. Exploitation is proceeding rapidly.

Bituminous Horizons in the Base of the Cretaceous.

The basement-beds of the Comanche series of Texas and the southern Indian Territory are bituminous in several places, notably between Emmet and Caddo, I. T. ; at Matubby springs, about 5 m. NW. of Caddo ; at Oakland, 16 m. 8W. of Emmet; and at Marietta.* At these localities the basement- sand of the Cretaceous is impregnated horizontally. Crossing Red river to the southward, rich bituminous impregnations are similarly found in the basement-sands near St. Jo, Montague county. Some 200 m. further S., in Burnet county, asphalt is again found in the vicinity of the town of Burnet, impregnat- ing small breccia at the base of the Cretaceous.

There are several minor beds of shale and clay in the Cre- taceous, which have furnished traces of petroleum and asphalt. A mile or two west of Austin, a little petroleum was found in the Del Rio clays. Traces of petroleum have frequently been found in the Eagle Ford shales, notably at Watter's station, K. of Austin, and in the N W. in Grayson county, on Red river.

The Corsicana Oil-Field.

Since 1891, illuminating oil has been produced in the vicin- ity of Corsicana, where the Standard Oil Co. has had a refin- ery. In 1900, the production of this district was 829,660 bbk The oil is of fine quality, analogous to that of the Washington county. Pa., field, and has a paraffine base. The wells are not gushers, but are pumped from depths averaging about 1100 ft.

Unlike the oil of the Beaumont field, that of Corsicana is distinctly a sheetroil, that is, it occurs in a definite geological stratum, namely, a horizon in the bituminous sandy clay shales of the Navarro beds, of the upper portion of the Gulf series of

See paper by Eldridge, previously cited.

The Beaumont And Other Oil-Fields Of Texas. 379

the Cretaceous. The geological position is closely near that of the Florence and Boulder oil-fields of Colorado.

An interesting feature of the Corsicana field is the fact that the Upper Cretaceous strata from which the oils are derived contain at least two distinct oil-bearing horizons; the upper- most has an asphaltum base, while the lower is of a parafline nature. The upper bed is encountered at Powell, about 20 m. E. of Corsicana; and I estimate that it is from 500 to 1000 ft. above the lower, which supplies the Corsicana wells.

These strata extend, with very slight variation, completely across Texas, from near Boston on Red river to near Eagle Pass on' the Rio Grande, in a curved line 750 m. long. An oil-asphaltum has been found in them at several places, notably a trace in the well at Bremond; a trace in eastern Travis county; near Elgin, near Lytton in Caldwell county; a few miles east of San Antonio ; and on the Sabinal in Medina county. The asphaltum-beds of Uvalde and Kinney counties are derived from practically the same strata. It is the writer's opinion that when the continuity of this bituminous formation across the State has been fully appreciated and exploited in a scientific manner, many productive spots, similar to the Cor- sicana basin, may be found.

The Nacogdoches Oil-Field.

A number of years ago, oil was struck at shallow depths in wells in southern Nacogdoches county, about 100 m. W. of N. from Beaumont. According to the studies of various geolo- gists, the horizon of this oil-field is near the top of the Clai- borne Eocene of the Tertiary.

A fine-grained quartz-sand, saturated with oil, which on the outcrop is a semi-asphalt, is apparently the source of the oil. It lies immediately below a green horizon, the outcrop of which is easily traceable by its blood-red soil, a product of the oxidation of glauconite.

Since the discovery ot oil at Beaumont, renewed interest has been awakened in Nacogdoches, and several wells are being drilled.

At many other localities throughout the outcrop of the Eocene Tertiary of Texas, traces of oil have been found. Much interest is now shown in the vicinity of Sutherland Springs,

880 Thb Bbaumont And Other Oil-Fields Of Texas.

Wilson county. A good oil is also reported 14 m. S. of Camp- bellton, near the junction of Atascosa, McMullen and Live Oak counties.

The Beaumokt Oil-Field.

This name the writer prefers to use for the oil-producing dis- trict within the area of the Coast Prairie of the Texas, Louisi- ana and Mexican region.

Discovery. — Before the first white man came, it was known that oil existed in small quantities in western Louisiana and Texas, within 100 m., more or less, of the present site of Beau- mont. It was a matter of rumor for many years that oil floated upon the sea just W. of Port Sabine. Petroleum springs ex- isted at several places, notably Lake Charles, Louisiana. It had also been encountered in the well-borings in western Louisiana, E. of Beaumont. As early as 1862, unprofitable attempts at drilling had been made at Sour Lake. Even at Beaumont, similar attempts failed. Until 1901, no man had obtained the oil in commercial quantities.

The finding of oil at Beaumont was not an accident, but, like all other great discoveries, the dramatic culmination of long and extensive research and many experiments, each of which was an important factor in the final result Capt. A. F. Lucas, to whom the glory of the crowning achievement is fairly due, had been, since 1892, carefully studying the geology of the coastal plain of western Louisiana and eastern Texas, with the view of developing its salt, sulphur, and petroleum. With the aid of every recorded observation which he could obtain, supplemented by his own experience and reasoning, he concluded that the structure and stratigraphy of Beaumont gave the best prospect of oil. Previous failures at this place were, in his judgment, due to mechanical difliculties, which could be overcome — an opinion which he fully confirmed by his work.

Capt. Lucas, a native of Austria, and graduate of the Polytechnic School of Gratz and of the Imperial Austrian naval school, had been for some ten years actively engaged in this country as a mining engineer, especially in the develop- ment and operation of the salt-mines of Louisiana.'*'

See hifl paper on '' Bock-Salt in Louisiana,'' 2Va9w.| zxiz., 402.

Thb Beaumont And Othbb Oil-Fields Of Texas. 381

In connection with this work, he found in one or two places indications of oil, and also of sulphur (of the existence of which, in that region, the famous Calcasieu deposit is a proof). Con- ceiving the plan of a systematic exploration for oil, he finally chose Beaumont, Texas, as the scene of operations. His first well, begun in 1899, was 575 ft. deep in March, 1900, and showed a trace of oil at the bottom, when the casing broke, and the well had to be abandoned. !N'ot daunted, he com- menced in October, 1900, another well beside the old one. The public will never realize the obstacles and difficulties which had to be overcome. One of Capt. Lucas's greatest technical achievements was the putting of a drill-hole through 1100 ft. of clay and quicksand. The methods and contrivances used by him made possible the other wells which have fol- lowed. This second well, which "came in" Jan. 19, 1901, was the famous " Lucas Gusher."

JSconomic Conditions. — The Beaumont oil, when first discov- ered, was found to be of a different quality from that of any other field, and many doubts arose as to its value and uses. Having a heavy base of asphaltum, and being thoroughly im- pregnated with sulphur, it was supposed to have no value as an illuminant, and many believed that the excess of sulphur would so corrode boilers that it could not be used as a fuel. This sul- phur was so apparent that on occasions, as on March 4, 1902, it filled the atmosphere, leaving a coating of sulphur on many of the houses in Beaumont, some 8 m. from the oil-field.

The chemical analysis of the oil is as follows :

Composition of Beaumont Oil. From Chemical Analyses by Prof.

F. a Thiele.

Per cent.

Kerosene, 36.00

Light lubricating oil, 21.05

Medinm labricating oil, 21.05

Heayy lubricating oil, 10.52

Asphalt, 6.34

LoM and gases, including sulphur, 5.04

Color of crude oil : brown, opaque. Sp. Gray., 0.9206 ; equivalent to 22 B. at 62.57 Fahr.

382 The Beaumont And Other Oil-Fields Of Texas.

Naphtha, 6.46"

Kerosene, . . . 35.00'

Lubricating oil, 43.90

Residue and gases, 14.65

Test of obtained kerosene :

Color, Prime white.

Sp. Grav., . . 0.872, equivalent to 30® B. at 65.5** Fahr.

Flash-point, . . . Fahr.

Fire-test, . . . 150° "

It was soon realized that, if fit for no other uses, this was an excellent fuel. After a year of experiment, it is now generally conceded that the oil has many excellent qualities, and that, after refining for the kerosenes, the remainder is as good a fuel and gas-making material as can be desired. Upon the basis of elaborate refinery, chemical and fuel-tests, made on large quantities, the following facts may be stated as estab- lished: (1) The Beaumont oil has a low flash-point of Fahr., which renders it an unsafe, or at least undesirable, cargo in tank-ships ; (2) refined by first distillation, it produces 80 per cent, of export illuminating-oil, leaving a residuum of good fuel-oil, which can be transported with perfect safety ; (3) the sulphur can be extracted if necessary, but when left in the oil has no injurious effect whatever upon the boilers, while it adds to the fuel value; (4) as a fuel, three barrels of this oil can be delivered by rail in any city in Texas at a price of $2.70, the price of bituminous coal being $5, and that of an- thracite coal JIO per ton. The oil may be laid down in New York, Philadelphia or Boston at 75 cents a barrel.

The flash-point Of the crude oil is too low for marine insur- ance, but this defect can be obviated by a profitable prelimi- nary refining, whereby the naphtha and kerosene are ex- tracted, and the flash-point is raised to a standard for safe shipment.

Immediately after the discovery at Spindle Top every acre within 50 m. was leased, and wells were started everywhere. Since it then took from three to six months to put down one of these costly wells, some time was required to show by exper- iment that all the oil in the immediate vicinity of Beaumont

Ths Bbaumont And Other Oil-Fields Of Texas. 383

was confined to Spindle Top hill, within an area of less than 300 acres,*

This was at first seriously discouraging. Many thought that if the oil was confined to this one small locality it would soon be exhausted, and the business would be at an end. Prudent operators at Spindle Top did not feel justified in making long- time contracts; and railways and factories, with the risk of an exhausted supply, before them, naturally hesitated to make the expensive changes required for the use of this fuel.

The " coming in " of Jennings, Sour Lake and Saratoga re- moved the fear of inadequate supply ; and no one now appre- hends an early cessation of production, even if Spindle Top should soon be exhausted, which has not been proved prob- able.

When the Beaumont well was discovered, the writer, aware that similar conditions existed over a wide area, ventured the following prophecy :

" It is entirely within the limit of probability that oU will be found at many places throughout the Coastal Prairie, especially in its southern extension toward the Bio Grande and in the northeastern State of Mexico at Tamaulipas. The outcrop of the Tertiary formations in southwest Texas, in Wilson, Atascosa, McMullen, Duval and other counties, is naturally rich in oil ; and the practical oil-men are risking their money in experimenting in this region. As the oil-bearing Tertiary strata extend east of the Missi|sippi into Mississippi and Alabama, it is not beyond possibility that oil may be found in these States."

The following data, showing the results of one year's exploi- tation, sufficiently confirm this declaration, which was received at that time with incredulity :

At Jennings, Louisiana, 160 m. east of Beaumont, a good flow of oil has been encountered. This well is 1830 ft. deep, and is described as a mild sort of " gusher." In the morning it spouts about 35 ft., and at other times just high enough to make a good flow. Although this oil is accompanied by a great deal of sand which chokes up the well, it demonstrates the broad geological fact which I asserted. Practical oil-men have such faith in the locality that a dozen or more well-rigs

The exact extent of the productive ground of Spindle Top hill has not yet been determined, because several of the largest corporations own large tracts on one side of the hill, where the limits have not been exploited. It is known that this field certainly exceeds 200 acres ; and most of the oil-men think it will reach 300 or 325 acres. It is still occasionally widened by new wells. TOii. XXXIII.— 24

384 The Beaumont And Other Oil-Fields Of Texas.

are at work. The sand-problem is a mechanical difficulty which all are confident will be overcome.

Proceeding west from Jennings toward Beaumont, oil has been found in varying quantities at Lake Charles, near Crowley, and in one or two other places.

At Sour Lake, 25 m. NW. of Beaumont, oil has been known to exist since 1 862 ; and a dozen years ago many pumping-wells were operated, and a small refinery was established. The field was abandoned ; but after the Beaumont discovery numerous well-rigs were set up to penetrate to greater depths. From seven to eleven different oil-strata were passed through, and in August, 1901, a well, similar to that at Jennings, was obtained by the Guffey people. Its product has not been reported.

On March 7, 1902, anotjier great oil-strike was made at Sour Lake, at a depth of 686 ft., by the Atlantic and Pacific Com- pany. It is said that the oil shot 150 ft. into the air, and was of better quality than that at Beaumont.

Twelve miles N. of Sour Lake, at the village of Saratoga, where the oil outcrops at the surface as maltha, it is said that a good oil-well has been obtained, flowing several thousand barrels per day.

Rockland, N. of Saratoga, is the next place where oil-deposits are found, and experimental boring has been going on here for some time. The sand-rock near the surface is completely im- pregnated with oil.

Between Sour Lake and Houston, 50 m. farther west, many experiments are in progress, but no success has been reported. In the city of Houston, I was informed by Major Cave, of the Houston and Texas Central Railway, that a small flow of oil had come from his well for many years.

Fifty miles S. of Houston, near the mouth of the Brazos river, in Brazoria county, there is a field which, according to Captain Lucas and the geological evidence which we possess, gives excellent indications for oil. There were no less than fourteen expensive well-rigs set up in this and Brazoria county, four of which were upon the remarkable hill known as Da- mon's Mound, one or two at Big Hill, and one at Keyser's Mound.

The wells on Damon's Mound encountered small flows of oil at depths of from 400 to 600 ft., exactly as at Beaumont;

The Beaumont And Other Oil-Fields Of Texas. 385

but SO far they have been unsuccessful in securing a commercial flow.

At Keyser's Mound, in the same county, about 6 m. north of Damons, and near the Brazos river, a flow of oil was struck at about 400 ft. ; but unfortunately the drillers were unable to cut ofi a tremendous flow of artesian water which was encoun- tered just above it; and, as a result, the well produces to-day a remarkable emulsion of oil and water.

The well at Velasco (Bryan Heights) struck, at about 600 ft., a flow of gas so violent that its roar could be heard for miles. As a gas-well, this was as remarkable a phenomenon as were the Spindle Top oil-" gushers." The flow of gas could never be controlled ; the well had to be abandoned ; and a new hole, started beside the old one, is now giving every indication of securing oil.

Proceeding southward throughout the vast desert of the Lower Rio Grande, small quantities of oil have been encoun- tered at several places, while still farther southward, at the end of our Coastal Plain, some miles from Beaumont, authentic reports have recently been received that flowing wells have been developed at Tampico, Mexico. Even as far south as the State of Tobasco, two flowing wells are reported. These results of a single year, although still fragmentary, are sufficient to rein- force our belief that in the future years the Beaumont field will furnish other profitable localities of commercial oil beside Spindle Top.

A Yearns Development — On January 10, 1902, one year from the date of the discovery of oil, there were 136 wells on Spindle Top. Operations for the first three months of the second year show a great increase ; the number of " gushers " has grown from 186 to 214, and more wells are drilling at present than at any previous time.

Three pipe-lines have been finished, two to Port Arthur (19 miles) and one to Sabine (24 miles). Pipe-lines jfrom Beau- mont to New Orleans and Beaumont to Galveston, Houston, and other Texas points, are contemplated.

On March 1, the tank-storage exceeded 5,000,000 barrels. Among the tanks of 37,500 bbl. capacity and over were 22 at El Vista, 28 at Gladys, and 33 at Port Arthur.

The demand for tank-cars has constantly increased. In Feb-

The Beaumont And Other Oil-Fields Of Texas.

ruary, 1902, 500 cars were added, making a total at that time of 1500. The Southern Pacific Railway has since purchased 250 tank-cars of 12,850 gallons capacity each, and many of the cars have already arrived at the loading tracks. Many com- panies now have ample shipping-facilities. In addition to the regular tank-car lines, there are between 800 and 1000 tank- cars owned by local oil-companies. A huge tank-car factory is being erected at Beaumont to supply the demand.

Tank-steamers also have been in great demand. Many ships have cleared from Port Arthur; but the supply nowhere ap- proximates the demand. The Guflfey Co. is constructing five steamers, one of which, to carry 60,000 ., is the largest ever made in America, and will equal any in the world.

The Gufiey Co. already has two refineries completed at Port Arthur, and another approaching completion. Work on five other refineries is progressing rapidly. Guifey Refinery No. 3, at Port Arthur, will have, a capacity of 2500 barrels per day. This company will ship no crude oil, but will bring the flash- point up from 120° to 145° and 150°, by taking out naphtha and kerosene, before shipment.

Within a year from its discovery, Beaumont oil is burning in Germany, England, Cuba, Mexico, New York and Philadel- phia. By its energy steamers are being propelled across the ocean, trains are hastening across the continent, electricity generated and artificial ice frozen in New York, ores ground and stamped in Mexico, Portland cement manufactured in Havana and Texas, and gas enriched in Philadelphia ; and this, too, while half the world is either unaware or incredulous of the value of this fuel.

A strong demand for the oil comes from the manufacturers of illuminating-gas. In March, this demand from New York and Philadelphia was great enough to justify a daily steamer from Port Arthur to those cities. The oil is also being sent to Atlanta and other cities for this purpose.

Many of the great railway-lines of Texas have changed or prepared to change from coal to oil as fuel for their locomo- tives. The oil is also being used in hundreds of small factoriess in Texas, such as breweries, brickyards, etc. Even the farmers are using it as a fuel sufliciently inexpensive to permit of pumping for irrigation.

The Beaumont And Other Oil-Fields Of Texas. 387

The prodaction of the Beaumont oil-field during its first year was limited for the lack of means of distribution. It is estimated, however, that 6,500,000 barrels were actually drawn from the great reservoir — one-half of which was stored in tanks and the remainder consumed, shipped or wasted.

The shipments for 1901 were 1,750,000 . ; for the first three months of 1902 they exceeded that total, those for March alone being more than 800,000 . The field will probably ship 20,000,000 . in 1902.

It is estimated that the development of this field has cost f 7,000,000, of which about $1,250,000 has been paid for labor. The tubing and well-drill rigs have cost, approximately, another million. Pipe-lines, lumber for derricks, and tanks for storing the oil, have consumed the remainder.

The average cost of sinking a well at Spindle Top is $7249. The 215 wells that are " in," together with the adjacent " dust- ers," have cost fully $2,000,000. Probably $50,000,000 more has been expended for purchases of land, transportation facili- ties, and other legitimate purposes. The capitalization of the 200 companies in the field is placed at $200,000,000.

Before Capt. Lucas's well came in, land could be purchased anywhere in the Coast Prairie country for less than $4.00 an acre. Millions of acres have since changed hands at fabulous prices, while every foot has been leased for favorable consid- erations. Thousands of acres of this land 150 miles from Beaumont have sold for as much as $1000 per acre. Land within the proved field has sold for nearly $1,000,000 an acre ; $900,000 having recently been paid for one acre. No sales were made for less than $200,000 per acre. Spindle Top to- day may be justly assessed at a valuation of $500,000 an acre, or $100,000,000. Two years ago it could have been bought for less than $10 an acre.

The 214 wells upon the field are owned by about one hun- dred companies. It is estimated that 120 of the wells are located upon 15 of the 200 acres of productive territory. These wells are in the hands of nearly as many individual companies, mostly small organizations without means for operation or facilities for outlet and transportation. The re- mainder of the territory is within the hands of four or five legitimate operators, who not only possess wells, but tank-

388 The Beaumont And Other Oil-Fields Of Texas.

cars, pipe-lines, refineries, etc., for handling and marketing the oil.

The Geology of the Beaumont Field.

The Codst Prairie. — This belt of prairie-land, from 10 to 60 miles wide, which borders the Gulf of Mexico for nearly 400 miles from the Mississippi in western Louisiana through Texas into Mexico, is one of the newest made and least understood of our American geographic provinces. It is a grass-covered constructional plain, newly reclaimed from the Gulf of Mexico. In general character it resembles very much the New Jersey flats of our northern coast, with which it has many features of age and mode of origin in common.

Topographically, it is almost level, sloping seaward at the rate of about one foot to the mile; its interior margin rises scarcely 100 ft. above the sea. It is impossible with present knowledge to delineate the interior border with exactness ; for belts of timber constantly encroach upon it. Its almost level surface is broken by a few low drainage-grooves. There are deep drowned bayous in Louisiana and east Texas ; but these become fewer and more faintly developed toward the Rio Grande.

No topographic surveys have ever been made of any portion of the Coast Prairie, and hence the slight irregularities of its contour are discernible only with difficulty. Until Capt. Lucas's investigations, certain low elevations, which have since become the most important features of the landscape, were hardly noticed. I allude to low swells or hills such as Spindle Top, which occur here and there, and now attract attention from their supposed relation to the occurrence of oil beneath them. These mounds or hills are in reality gentle swells.

Until the past decade this country, which is swampy in places and in its southwestern extension semi-arid, was considered good only for cattle-raising. For fifty years, immigration passed beyond it to the more fertile portions of the State. Prior to the recent oil boom, however, it was acquiring a great impetus through the development of rice-culture, and to-day it is one of the most active industrial sections of the Union.

Geology of the Coast Prairie, — The low relief of the Coast Prairie, the absence of extensive natural or artificial cuttings and the mantle of vegetation render difficult the study of the

The Bbaumont And Other Oil-Fiblds Of Texas. 389

problems of its stratigraphy and structure. We know that this prairie is underlaid to an indefinite depth by a series of sea-muds and sands similar to the present marginal deposits of the Gulf. On a previous page I have given the geological series which should underlie the prairie, and called attention to the difficulty of classifying the later beds. These late Tertiary (Neocene) and Pleistocene formations which succeed the Frio clays of Kennedy (the top of the Angelina series), underlie the Coast Prairie, and contain the oil, have never been classified, and may be called the X beds until a definite classification is made. In addition to very recent alluvium and loam, they may include the formations described in Louisiana as the " Hud- son " and Grand Gulf." Paleontologists have also identified shells from the Galveston and Beaumont wells, which they re- ferred to the Miocene ; but no geologist has ever identified for- mations of this age outcropping at the surface in the Texas series.

No proof has been obtained of the total thickness of the X beds nor the depth of the top of the Eocene Tertiary, beneath the Coast Prairie. In fact not one of the drill-holes in the Coast Prairie, the deepest of which was the well at Galveston, Texas (8050 ft.), has ever penetrated to it. According to the section of this well, there are 2920 ft of such strata beneath the Texas Coast Prairie of Recent, Pleistocene and Miocene age.

Some sections have been published which convey an idea of the material of the unconsolidated beds. They are composed almost entirely of unconsolidated material, which weathers into a mantle of soil. One section at Beaumont shows the strata down to the oil-bearing rocks. Another, of the deep well at Galveston, Texas, includes the equivalents of all the strata passed through in the Beaumont well, together with 2000 ft. of lower, and probably from 100 to 8000 ft. of higher, beds.

A third section is that of the Louisiana Petroleum and Coal Oil Co.'s well, 1280 ft. deep, in Calcasieu parish, on one of two small islands in the marsh which forms the head of the Bayou Choupique. The section, originally given by Hilgard, is re- published in the Geological Survey Report of Louisiana for 1899, page 25.

A fourth section is that of the wells at Belle Isle, given in the Louisiana Geological Survey Report for 1899, Plate XXII.

390 The Beaumont And Other Oil-Fields Of Texas.

Some information concerning the formation of the Coast Prairie, with a risumi of previous work, is found in a prelimi- nary report of the geology of Louisiana, transmitted in Novem- ber, 1899, but without date of publication on the title-page (probably 1900). On the map accompanying this report, it is remarked that the distribution of the post-Eocene deposits is based mainly on previous surveys.

A few fragmentary data concerning the character of the formation have been given by Dr. Loughridge in the special report on cotton production for the Ninth Census ; but, as a whole, the Neocene, Pleistocene and Recent formations imme- diately underlying the Coast Prairie are still unstudied and un- correlated.

Several of these sections would lead the reader to infer that the bottom of the JT beds had been reached when the bodies of salt, sulphur and gypsum were encountered, and that these materials are of Cretaceous age. Evidence will be presented later to show that this may not be the case.

According to a special report by Hilgard for the Louisiana Geological Survey, the Five Islands are the erosion-formed out- liers of a Cretaceous ridge or backbone which traverses Louisiana from its NW. corner in the direction of Vermilion Bay ; and many geologists have referred the salt- and sulphur- beds to the Cretaceous.

A sifting of all the evidence upon the subject affords no proof of the Cretaceous age of the salt islands, which has been asserted solely on lithologic grounds, paleontologic evi- dence being entirely lacking. It is true that there is a change of material in several of the drill-holes, as, for instance, from the salt of the salt island and Damon's Mound, and the dolo- mite of Big Hill ; but if these materials have originated by secondary replacement, as I maintain may have happened, they may be of post-Tertiary age.

Structure of the Coast Prairie. — The Coast Prairie is topo- graphically monotonous and so near to sea level, and the geological formations so unconsolidated and indeterminate, that there are no surface factors to enable one to determine the elementary features of structural deformation, such as the anticlines and synclines, which are so easily traceable in other regions where indurated rocks abound. Notwithstanding its

The Bbaumont And Other Oil-Fields Of Texas. 391

apparent simplicity, however, there are some knotty problems in the underground structure of the Coast Prairie, which pre- sents a peculiar exception to all the rest of the Coastal Plain. As already observed, the outcrops of lower and lower beds occur in succession from the coast inward. But this is not true of the X beds. There is distinct evidence that, among these, newer beds overlap older formations, which do not out- crop at the surface anywhere in the Coastal Plain. Thus, Miocene fossils have been recognized in the Galveston and Beaumont wells, where no formations of this age are known to outcrop anywhere at the surface. The stratigraphic unconform- ities noted by Kennedy between the Camden and Angelina series, and the Angelina series and the X beds, also have an important bearing on this question.

There is some evidence that the Coast Prairie overlaps con- ceal a line of serious deformation, which may be a sharp fold, with an increased dip coastward, or a zone of faulting. The normal dip of the Eocene strata immediately W. of the Coastal Plain is from 10 to 20 ft. per mile. If this rate of inclination continued to the coast, these strata would be buried only from 500 to 1000 ft. But, as I have shown, they are prob- ably more than 3000 fl below the surface, showing either a rapid change in dip to 60 ft. per mile, or a downthrow-fault.

If such faulting or deformation exists beneath the Coast Prairie, overlapped and buried by later surface formations, the fact is most important. I shall recur to it later.

The Louisiana part of the prairie is acknowledged to be a subsiding area, as attested by actual bench-marks, the drowned character of the bayous, and the circle of cypress growth on the swamps. I know of no actual previous observations bear- ing upon the isostasy of the Texas portion of the prairie. McGee, in a recent article in the National Geographic Magazine assumes that it is likewise subsiding ; but observations made within the past year lead me to believe that west of the Trinity river, at least as far south as the mouth of the Colorado — be- yond which we know nothing — the plain is rising. Between the Trinity and the Colorado all the streams have new-cut chan- nels, characteristic of rising land, while the Brazos is actually cutting down through its own alluvium at sea-level, and for many miles above its mouth.

392 The Beaumont An0 Other Oil-Fields Of Texas.

In the generally monotonous monoclinal structure there are a few wrinkles or small swells, likely to escape the eye of even the trained observer, and yet of a character which may have an important bearing on the oil-problem. These are the circular and oval mounds already described, which were first recognized by Capt. Lucas. When he pointed out Spindle Top hill to me, my eye could hardly detect it; for it rises by a gradual slope only 10 ft. above the surrounding prairie plains. I was still more incredulous when he insisted that this mound, only 200 acres in extent, was an uplifted dome. But Capt Lucas said that I would be convinced of the uplift if I could see Damon's Mound in Brazoria county. In August, 1901, I visited that place, and then returned for a second look at Spindle Top, and was convinced that, if these hills are not recent quaquaversal uplifts, no other known hypothesis will explain them.

Damon's Mound is an elliptical hill, a mile or more in greater diameter, rising 90 ft. above the surrounding level. Its profile is everywhere convex, and it is not a hill of erosion or of vol- canic material. Furthermore, a bed of limestone follows the contour of its surface, showing deformation. The ascent of the plain will not carry the latter to the height of this mound for 100 m. interior-ward.

Phenomena Accompanying the Oil in the Beaumont Field. — By studies and drill-sections of the Coast Prairie, the following facts have been developed :

1. The oil is closely associated with the mounds, occurring on their slopes or summits.

2. The mounds are usually anticlinal or quaquaversal in structure.

3. Most of the chemical phenomena of the Lucas group occur in all these mounds in varying proportions.

4. In some localities, hot water has been struck below the oil.

5. In the original Lucas well, the oil itself is hot.

The oil seems to occur, not in any definite, continuous stratum, but in spots of many strata, under varying conditions. At several places, notably Rockland, Saratoga and Sour Lake, it is found at the surface as a maltha or asphaltum, impregnat- ing spots in beds of sand, which are indurated by it. At Jen- nings, Beaumont, Sour Lake, and other localities, several — at

The Beaumont And Other Oil-Fields Of Texas. 393

Sour Lake, for instance, eleven — " seeps " of oil have been encountered.

Gas in immense quantities, and frequently under such pres- sure as to wreck the wells, has been struck before reaching the oil. This has occurred several times at Spindle Top, twice at Sour Lake, and once at Velasco, where the destructive effect was terrific.

Sulphur and sulphuretted hydrogen gas occur in intimate association* with the Beaumont oil. In fact, the oil itself is said to contain from 1 to 2 per cent, of sulphur, and the fumes of sulphuretted hydrogen are strong in the vicinity of the wells.

Captain Lucas early noticed that sulphuretted hydrogen, es- caping from the earth under certain conditions, deposited sul- phur in crevices near the surface. Such phenomena he observed at Spindle Top before commencing his well. At High Island, Galveston county, work was temporarily suspended on a well- hole, and the orifice was stopped with hay, in order to prevent obstruction from debris. Afterwards, when this plug was with- drawn, the hay was found to be imbedded in a matrix of sul- phur, undoubtedly deposited from the escaping gas. At Da- mon's Mound, Brazoria county, sulphur was found near the sur- face only, in small joints and fissures ; and a clay impregnated with it, used as an ointment by the Indians who formerly in- habited the coast country, was subsequently mined and sold as a medicine by a company of Americans.

Underground bodies of sulphur, associated with the oil by natural processes, have been found in many localities. The Calcasieu section of Hilgard shows at 540 ft. in depth solid sulphur rock,'' similar to that encountered at 1040 ft. in the Beaumont well. At Damon's Mound a bed of sulphur from 10 to 40 ft, thick was encountered above the salt. Crystals of free sulphur also occur in cap-rock overlying the Spindle Top oil.

The following is reported of the well bored by Boughton & Wynn for the Higgins Oil Co. at Spindle Top, about 800 ft. from the Lucas well. I cannot vouch for the correctness of the state- ment:

'' The drillers claim that the oil-pool struck by their well is 40 ft deep, and that the oil rests upon a bed of sulphur. After the oil was struck, the borers per- mitted the pipe to sink until it struck bottom, which it did at the distance of 40 ft. The drillers then claim to have bored 4 ft into a bed of pure sulphur."

894 Thb Beaumont And Other Oil-Fields Of Texas.

The bodies of sulphur are probably a by-product of the for- mation of the oil, which, at Spindle Top, is not only highly sat- urated with sulphuretted hydrogen, but contains by chemical analysis from 1.5 to 3 per cent, of sulphur. It was Capt. Lucas who discovered the relation between the sulphuretted hydrogen fumaroles, gas-springs and sulphur incrustations at the surface, and the bodies of subterranean oil ; and it was his belief in this association that led him to seek for oil on Spindle Top hill.

The bodies of salt discovered beneath the hills of the Coast Prairie are of remarkable size, thickness and purity, — notably those in Louisiana, and one discovered within the past few months at Damon's Mound, in Brazoria county, Texas.

The salt islands of Louisiana were described by Captain Lucas in the Transactions of the American Listitute of Mining En- gineers before his discovery of oil at Beaumont.* These so- called islands, rising from 80 to 250 ft. above the surrounding marshes of the Coast Prairie, are hills beneath layers of strati- fied clay and sand. They belong to the same group of topo- graphic phenomena as Spindle Top hill at Beaumont.

By sinking through the superstructure of sand and clay, Capt. Lucas located the salt-bodies and determined their horizontal extent, developing also the important fact that, though limited in diameter, they were of great depth, — that of Jefferson Island having been penetrated for 2100 ft. without reaching bottom.

Another important fact pointed out in Capt. Lucas's paper was that the substrata of the southeastern part of Belle Isle, above and down to the rock-salt, were heavily impregnated with petroleum. Several calcareous strata containing sulphur were also encountered, suggesting to him that more thorough exploration might develop a sulphur-deposit like the great Cal- casieu deposit, and showing the association of these three ma- terials.

All geologists who have expressed an opinion have com- mitted themselves to the theory that these salt-masses were originally deposited in the sea and covered with later sediments. Capt. Lucas also accepted this hypothesis. The theory as stated by Adamsf was that, " near the close of the Cretaceous period, beds of rock-salt and gypsum were evidently precipitated in the land-locked remnants of the retreating sea."

♦ Trans., xibc., 462 et aeq. f U- S, QeoL Sur., BuUetin No. 184, p. 49.

Tab Beaumont And Other Oil-Fields Of Texas. 395

The sediments of the lagoons which in former times, as to- day, bordered the Gulf of Mexico, were undoubtedly very sa- line ; but we have no instances at present to lead us to suspect or believe that there have ever been conditions for the accumu- lation, by surface evaporation in such lagoons, of the enormous thickness of flalt now found beneath the Coast Prairie mounds of Louisiana and Texas.

These vast salt-bodies are intimate historic associates of the oil, and record the past location of the circulation of saline waters, which were transporting agents in the distribution of the oil.

Since studying the phenomena of the Beaumont field, the writer has gradually developed another hypothesis, namely, that these salt bodies are the result of secondary replacement in the strata through the agency of the ascending circulation of saturated briny waters, as elsewhere explained.

Still another interesting phenomenon is the occurrence of dolomite. The oil of Spindle Top is said to occur in a cavern- ous mass of this material. At Big Hill, Jefferson county, which is one of the most conspicuous of the mounds, the drill, after going down 300 ft, penetrated a mass of solid, coarsely crys- talline dolomite, in which it continued to nearly 1375 ft. At 900 ft. a small seep of oil was struck in the dolomite. This would suggest, at first glance, that a boss of ancient crystalline rock had been encountered ; but such is probably not the case, as I shall endeavor to show.

In only one well, so far as I am able to ascertain, has the hot salt water been encountered, which would be expected to follow the oil. This was in the Sour Lake field, where, as I am informed by the owner, a heavy flow of hot salt water was struck at about 1400 ft. — a lower level than that of the " gusher "- oil of that vicinity.

The fact that the oil in the original Lucas gusher had a tem- perature of over 110® F. is most important. This phenomenon seems to have been overlooked heretofore by those who have studied the field.

Explorations have shown the following downward series in the quaquaversal hills : (1) a matrix or overlay of the typical Coast Prairie formations; (2) oil-phenomena, consisting of sulphuretted hydrogen gas, escaping superficially, and secon-

396 Thb Beaumont And Other Oil-Fields Of Texas.

dary deposits of sulphur in the strata through which the sul- phuretted gas has ascended ; (3) oil, mixed with considerable sulphur and sulphuretted hydrogen ; (4) sulphur, as a precipi- tate or sediment of the oil ; (5) sodium chloride and magnesian lime carbonate, as after-products of the oil ; and (6) hot salt water, under great hydrostatic pressure.

Geological Source and Distribution of the Oil.

The ablest geological experts and practical oil-men have found the conditions in the Beaumont field different in every detail from those of all previously discovered fields, especially those of Ohio, California, West Virginia and Pennsylvania. The magnificent work of Orton in Ohio, White in Virginia, and Lesley and others in Pennsylvania, is inapplicable in this field.

The writer, like other geologists, assumed at first that the oil-deposit was more or less of the sheet or blanket type, and for a while proceeded upon that theory, until it was upset by experiments around Spindle Top. A year ago I was inclined to believe that the Beaumont oil was, like that of the Trenton, Berea and Corsicana fields, indigenous to certain strata. But we are unable to define and describe such strata; and all evi- dence now tends to disprove that proposition.

While science has said, frankly, " We do not know, but we shall learn," fakirs of every imaginable kind and well-meaning practitioners from other fields have given advice in abundance. The man with the divining-switch ; the boy who could see underground streams blindfold in the night; the electrical- indicator man; the Pennsylvania oil-driller who recognized Pleistocene and Recent gravels on the surface as identical with the Paleozoic conglomerates of his native State ; and a host of quack-geologists, have reaped a rich harvest in this field through the foolish and fruitless expenditure of much money.

Before the discovery at Spindle Top, there was only one man whose ideas, although not yet co-ordinated into a theory, ap- proximately fitted the observed conditions. Of course I refer to Capt. Lucas, who, in his explorations of the Coastal Plain, seeking successively salt, sulphur and oil, had observed the association of oil, sulphur, sulphuretted hydrogen gas, gypsum, dolomite and salt, constituting collectively what might be termed

Thb Beaumont And Other Oil-Fields Of Texas. 897

the oil-phenomena, representing a group of secondary products, as distinguished from the mother-strata or sediments out of which they had heen produced. Moreover, so far as I am aware, he first pointed out the existence of anticlinal hills in the Coast Prairie, and their connection with the oil-phenomena. Concerning the origin and geology of the oil, however, he pre- sented no opinions.

Capt. Lucas also attached much significance to certain sur- face-phenomena, indicating that the sulphuretted hydrogen, es- caping upward, either acidulated the surface-waters or deposited incrustations of sulphur in the soil. He inclined to believe that the mounds themselves were in some manner the result of the gas-pressure ; and I think he favored the notion of hori- zontal distribution along lines of strike.

An Explanatory Hypothesis.

The writer has in mind a hypothesis, not hitherto advanced, BO far as he is aware, which co-ordinates Capt. Lucas' data and explains that which he omitted, the source and distribution of the oil, salt-islands, sulphur, sulphuretted hydrogen gas, and dolomite. This hypothesis is offered with hesitation, not as a final explanation, but iti the hope that it may serve as a basis for discussion, through which the truth may be reached. I think it fully interprets the Lucas group of phenomena, and accounts for the mystery of Spindle Top far more satisfactorily than any other thus far presented, and that it may also account for the independent origin of the sulphur, sulphuretted hydro- gen and gypsum, regardless of their association with the oil.

This hypothesis is as follows : The oilr and salt-pockets of the Texas Coastal Plain are probably not indigenous to the strata in which they are found but are the resultant products of columns of hot saline waters which have ascended under hydrostatic pressure at points altmg lines of structural weakness through thousands of feet of stialcj sandy and marine littoral sediments of the Coastal Plain sectioUy through which oil and sand are disseminated in more or less minute quantities. The oily loith sulphur may have been floated upward on these waters and the salt and dolomite may have been crystallized from the saturated solution.

The channels of thee ascending waters may have been in places of structural weakness, such as fissures, which probably atone time con-

398 The Beaumont And Other Oil-Fields Of Texas.

tinned to the surface but may have been sealed by the deposition of the later overlapping strata now capping the oil-pools. Such features when occurring under gentle anticlines may explain the collection of oil beneath the surface in pools.

The following known data may be adduced in support of this hypothesis : (1) The absence, at the depth of the Beaumont wells, of any local sheet or stratum from which it is probable that the tremendous body of oil could have been generated ; (2) the probable existence of nearly 10,000 ft. of Cretaceous, Tertiary, Quaternary and Recent unconsolidated sediments beneath the surface of the Coastal Plain, as demonstrated by the deep well at Galveston, and studies of the outcrops farther inland : (3) the dip of these strata beneath the Coast Prairie at, a low angle, from the interior coastward ; (4) the oil dissem- inated in small quantities in many of these strata ; (5) the ex- istence of seven or eight distinct reservoirs of artesian water in this series of strata, at depths which increase coastward ; (6) the fact, demonstrated by artesian wells, that the water becomes hotter and more saline with increasing depth, thereby increas- ing its capacity for the collection and flotation of oil ; (7) the intense hydrostatic pressure in these water-bearing strata, which apparently continue beneath the Coastal Plain; (8) the fact that this water has risen in spots along lines of fissure which are probably later, and are capped by 1000 ft. or more of the still later strata of the Coastal Prairie.

The evidence of these statements is as follows :

1. Experiments at Spindle Top, Saratoga, Jennings, Sour Lake and Velasco show that the accumulations of oil sufficient to produce gushers are not indigenous to the particular stratum in which they are found, but have been collected there as a result of other causes. It is also certain that the oil occurs in under- ground pools, which are related to the supposed anticlinal mounds in the new-made Recent Coast Prairie.

The main supply of oil at Spindle Top averages 1000 ft. in depth, and may be in strata of Pliocene or allied Miocene age. But that this stratum in which the oil occurs is not continu- ously impregnated as a widespread sheet is testified by the barren ground developed all around Spindle Top. Nor do the many drill-holes bored up to this date reveal any formation in the upper portion of the Coastal Plain capiable of generating

The Bbaumont And Other Oil-Fields Of Texas.

the vast quantity of oil found at Spindle Top, whatever its ori- gin. These oils are not associated with extensive beds of either plant or animal remains from which the oil might have been generated. At one place, Saratoga, where they outcrop, they apparently occur in ferruginous sands.

A faint trace of oil is usually encountered at from 400 to 600 ft. in depth, throughout the entire three hundred miles from Damon's Mound to Jennings. This was probably the first " seep " oil struck at about 600 or 700 ft. in the Lucas well, and has been encountered at many other places. It may be a local horizon ; but it has not been found to be always un- derlaid by a great " gusher " stratum, or by any signs of such a thing. That there are shallow strata beneath the Coastal Plain which are oil-bearing is apparent ; but the product of all of these put together would not supply one " gusher."

2. The now classical section of the deep well at Galveston, only a short distance from Beaumont, shows that there are at least 8000 ft. of unconsolidated Gulf littoral sediments, of later age than the Eocene Tertiary.

Beneath this, there is every reason to believe (from its out- crop to the westward and dip toward the Gulf Prairie) that there must be an additional 300 ft. of Eocene Tertiary sands and clays. Similarly, west of the Tertiary, and dipping beneath it, geologists have measured at least 4000 ft. of marine Creta- ceous formations, also dipping directly beneath the Coastal Plain.

If all these strata do (and no evidence has been as yet pre- sented to show that they do not) extend beneath the Coast Prairie, then we have beneath it at least 10,000 ft. of Creta- -ceous and later sediments, known to be (with the exception of 1000 ft. of consolidated limestones) almost entirely composed of more or less littoral, terrigenous, bituminous and ferruginous clay and sand.

8. The dip of the buried portion of the strata of the Cre- taceous and Eocene series beneath the present coast prairie is evident from the minute studies of the outcrops of these strata towards the interior. The Cretaceous strata dip toward the Coast Prairie from 25 to 40 ft. per mile, as shown with great minuteness in the authors monograph of the Cretaceous forma- tions.* The dips of the Eocene Tertiary, from 30 to 10 ft. per

2l8i Ann. Bep. 17. S, Oeol, Surv., Part VII. VOL. XXXIII. — 26

400 The Bbaumont And Other Oil-Fields Of Texas.

mile, are given in the various reports of the Texas Surveys. While no one can say positively that these strata are beneath the Coast Prairie, induction leads to no other conclusion, and absolutely no reason can be advanced to prove that they are not.

4. Of the 22,000 ft. of sedimentaries in the Texas section, all but less than 2000 ft. are unconsolidated clays and sands, which may be more or less bituminous. Some of the lime- stones are also bituminous. Oil or bitumen has been found in at least a dozen horizons of the section. The older or Paleo- zoic group contains one in the Ordovician, and two or three in the Carboniferous (as at Brownwood, and at Henrietta, in In- dian Territory). Of the strata comprising the later grand group underlying the Coastal Plain, there are five oil horizons in the Cretaceous : one in the base of the lower Cretaceous (at St. Jo and Burnet) ; one in the Del Rio clays at Austin ; one in the Eagle Ford clays in Grayson county ; two in the Navarro beds of Corsicana; several in the Eocene — notably that at Nar cogdoches — and several in the post-Eocene at Beaumont.

In two instances, in Texas, bituminous matter (asphaltum) is found in apparently indigenous beds of lime-shell conglomerate. One of these is the shell-breccia bed of the Travis Peak formar tion at Port Mountain, in Burnet county ; the other is the shell- breccia in the upper Cretaceous at Cline, from which the Uvalde asphaltum is obtained.

The oil of the Corsicana field and that of San Antonio is derived from the shales of the Upper Cretaceous. The same strata which produce oil at Corsicana would, if continued, probably be embedded at least 4000 or 5000 ft. beneath Beau- mont.

.The strata of the Eocene Tertiary present every favorable condition for the generation of petroleum, whether this ma- terial be derived from the decomposition of marine organisms, as alleged by some, or from the hydro-carbons generated by vegetable matter, as believed by others. There are vast accu- mulations of both materials in eastern Texas.

It is an interesting fact that asphalts and oils rich in asphal- tum occur in terrigenous (land-derived) sediments of the nature, age and general character of the East Texas Eocene,

The Beaumont And Other Oil-Piblds Of Texas. 401

around the entire perimeter of the Qalf of Mexico and the Caribbean Sea. The asphaltB of Tamaulipas in Mexico, Vera Cruz, the Isthmus of Panama and Cuba, as well as the great asphalt-deposits of Trinidad, Barbados and Venezuela, all come from beds of this character.

The oil from the Nacogdoches well is derived from near the top of the lignitic formations (Claiborne beds) of the Eocene Tertiary, the position of which has been definitely ascertained by geological study.

The Xbeds (post-Eocene) of the Coast Prairie are apparently rich in oily spots.

If a drill-hole could be continued to a depth of 10,000 ft. below Beaumont, it should encounter : first, the Nacogdoches oil-stratum ; next, the bituminous shales of the Eocene ; next, the oil-shales of the Corsicana field; next, the Eagle Ford (Colorado) bituminous shales ; then the bituminous beds which furnish the asphaltum of St. Jo and Burnet ; and, finally, the oil-shales of the Carboniferous. None of these strata were en- countered within 3000 ft. of the surface in the deep wells at Gal- veston, or in any of the wells of the Coastal Plain. Between the Eocene or Claiborne stratum of Nacogdoches and the upper- most Pleistocene stratum of Beaumont there are thousands of feet of gypsiferous clays and sands in which nature may now be distilling oil.

5. That the strata dipping beneath the Coast Prairie contain many beds (reservoirs) of artesian water is proved by extensive records and observations. These horizons are fully described in the writer's paper on the " Artesian W.aters of Black and Orand Prairies.*

6. This water increases in temperature with depth, and in its capacity for taking in solution the solvent salts and for upward flotation of the oil gathered in particles from the various strata through which it passes in greatest quantity. The fact that the water increases in temperature and salinity is conclusively proved by a line of wells, 100 m. in length, between Comanche and Marlin, in the lower portion of the Cretaceous series. The

♦ 21rf Anm Bep. U. S. QtoL ,, Part VIL, p. 387, Washington, D. C,

402 The Bbaumont And Other Oil-Fields Of Texas.

same stratum whicli furnishes water at both places outcrops at Comanche and supplies good potable water at almost every atmospheric temperature. At Marlin, 100 m. eastward, this water comes from a depth of 3200 ft., has a temperature of nearly 140° F., and is excessively saline and sulphurous. Should the rate continue from Marlin to Galveston, this stratum would be, at the latter place, nearly 1000 ft. below the surface, and intensely heated and saline.

7. If the lowest water-sands of the Cretaceous of Texas are embedded beneath the Coastal Plain, several thousand feet below their outcrop, they must be under tremendous hydro- static pressure. Their water must ever pass upward, and would take advantage of any structural weakness in the overlying beds to do so.

8. In the discussion of the geology of the Coast Prairie, I have given some evidence of the existence of a strong mono- clinal fold or faulting beneath the Coast Prairie.

There is much evidence that the present and former Coastal Plains of Texaa, marking the recedence of the old shore-line of the Gulf of Mexico from the Rocky Mountain region to its present site, has experienced periods of pause, producing a series of concentric shore-lines, accompanied by faulting. It is a singular fact that in another part of Texas, adjacent to a region which was at one time a coast-line of the Gulf of Mexico, there existed such a line of weakness. The great Balcones fault, which the writer has frequently described, is of this char- acter. It is very probable that, along the present coast-line, similar faulting took place in Neocene time, and that the evi- dence thereof has been obscured by overlapping of the Grand Gulf and later formations, which veil the Coast Prairie.

It is also true that there are unconformities in the coastal section, such as the one described by Kennedy, which might have overlaid such fault-fissures in the Coast Prairie with more recent deposits.

K these deeply embedded water-bearing strata under tre- mendous hydrostatic head exist beneath the Coast Prairie, thir waters would pass through any natural channels, such as fault-fissures, through all of the known sheet-oil horizons of Texas, except those of the Carboniferous formation. Such

The Beaumont And Other Oil-Fields Of Texas. 408

hot water would gather from the rocks, which are known to contain them, oil, salt, lime, sulphur and gypsum ; and the oil gathered from these strata would be floated on the ascending saline waters.

If ascending columns of oil and water of this character should meet resistance near the surface, we could well con- ceive of the formation of such a pool as that beneath Spindle Top hill. To produce such a formation, which would be prac- tically like the end of a " mushroom " bullet, there must be resistance ; and this resistance would naturally come from an impervious formation. The overlap of the upper X beds of the Coast Prairie, stopping the free exit of the water upward through the fault-lines, would produce such a resistance ; and this overlap we believe to have taken place.

At any rate, should such a column of ascending water, with oil on top of it, reach a resistance near the surface, a subter- ranean pool of oil would result, such as we find at Spindle Top. Furthermore, the reaction which would take place in the column of water below the oil could theoretically account for all of the after-phenomena of the Coast Prairie mounds, such as the salt- islands of Louisiana and Damon's Mound, and the dolomite of Big Hill.

It is a remarkably interesting fact that in the mammoth ar- tesian springs of the Balcones fault-zone, between Austin and Del Rio, we have an analogous group of data, showing the rise of subterranean water in spots along a line of faulting. Along this line great columns of water are now rising, not continu- ously, but in spots, like the supposed ancient artesian springs of the Coast Prairie. I allude to the series of springs at Aus- tin, San Marcos, New Braunfels, San Antonio, Fort Clark and Del Rid.*

It is true that these waters do not bring any perceptible oil to the surface; but this is easily explained, since they pass mostly through limestones and non-bituminous strata. On the other hand, had they been, as the old structure of the Coast Prairie has been, overlapped by more recent formations, they

See "(Geology of the Edwards Plateau, with Beference to the Ckscurrence of Underground Waters," \%ihAnn, Bep, U, 8, Qed. Surv,, Part II., p 193.

404 The Beaumont And Other Oil-Fields Of Texas.

would constitute columns of suppressed water like those we have theoretically supposed beneath the Coast Prairie.

A remarkable discovery has been made within the past few weeks, indicating the correctness, from a scientific point of view, of Capt. Lucas's theory that the mounds were the loci of his groups of oil-phenomena, and supporting the hypothesis of ascending waters. In Brazoria county, Texas, some 350 m. west of Belle Island, Louisiana (almost as far as Philadelphia from Cleveland), the lonely mound known as Damon's Mound, similar to those of the Louisiana salt-islands, rises out of the prairie. This has been penetrated, and proved to be an anti- clinal dome similar to that of Belle Isle, with a similar strati- graphic section: Pleistocene sand and clay, with traces of sulphur in the surface-layers; oil; then sulphur; and, for its lower 700 ft., pure rock-salt, with occasional traces of oil, demonstrating the occurrence of the latter substance, but not in commercial quantities.

Now the question arises, is Damon's Mound a fossil-oil hill, beneath which the oil once existed but has passed away? If so, why not also the Five Islands, and other palt-islands of Louisiana ?

Postscript.

(February 14, 1903.)

Since the above paper was written, nearly a year ago, many events have taken place in the Beaumont oil-field. Jennings, Louisiana, and Sour Lake' and Saratoga, Texas, have become productive fields. Oil is also reported in commercial quantities from several other localities. The wells of Spindle Top Hill, on the other hand, have mostly ceased to flow and are now pumped, a result which was naturally to have been expected from the drilling of nearly three hundred (300) wells within a limited space of 160 acres. All in all, the development of the field has been satisfactory ; and it is safe to say that the Beau- mont oil-field, as a whole, notwithstanding the hundreds of experimental failures, has developed as rapidly as any other field ever discovered, and it is reasonable to expect that new localities will be found as years roll by.

The use of the crude oil has steadily increased until this ma-

The Beaumont And Other Oil-Fields Of Texas. 405

terial, which, at the time of its discovery, was pronounced to be unfit for any purpose, is now refined, and sells for as high as 60 to 70 cents a barrel. All of the railways of Texas are using oil, and the Southern Pacific Railway has recently pur- chased the entire Saratoga fields, and runs its engines from the Atlantic to the Pacific with the Texas material. The legitimate investors have made money and the honest companies are pay- ing dividends. The field has subsided from the condition of frenzied excitement and " wildcat " speculation which marked the first days of its discovery, and has settled down to one of systematic business organization and production. Pipe-lines, refineries and tank-cars are now in great abundance. The sta- tistics are not available for the production of the whole field, but the following, taken from the Engineermg and Mining Jour- nal for February 7, 1903 (p. 239), shows the production of Spindle Top Hill for 1902 :

Beaumont Oil-Production in 1902. — Shipments, January 1 to June 80, 3,768,000 .; July, 850,000; August, 915,000 September, 828,815 ; October, 916,979 ; November, 844,791 December, 1,004,569 ; total shipments, 1902, 9,128,154 . local consumption, 500,000 . ; waste, 1902, 400,000 . Increased oil in store over December 31, 6,105,000 . ; total production, 1902, 16,133,154 .

" Total production, 1901, 4,190,000 .

Total production of field, 20,323,154 .

" Iron tankage completed, 7,280,000 . ; earthen res- ervoirs completed, 7,100,000 . ; total tankage, 14,380,000 .

" Oil in store December 31, 1902, 7,105,000 ; prices for crude in 1902 varied from 2 to 50 cents a bbl. in tanks.''

406 Golb-Fibld Of Thb Statb Of Minas Gbraes, Brazil.

The Gold-Pield of the State of Minas Geraes, Brazil.

BY HERBERT KILBURN SCOTT, LONDON, ENGLAND. (New York and Philadelphia Meeting, February and May, 1902.)

The information in this paper was collected by the author during a five years' residence in the State of Minas Geraes. Outside the State itself, very little is known of the gold-field. Such accounts as have been published are antiquated and con- tained in publications mostly out of print. The increased at- tention now attracted to the natural resources of Brazil, and the probability that American capital will be, in the near future, largely invested there, will make an up-to-date account specially useful at this time.

I. Historical and General.

Soon after the Jesuits founded what is to-day the city of SSo Paulo, gold was discovered in the streams of the neighborhood ; and this incited the natives, known as pavUstas to look for it farther afield. After many expeditions into the interior, gold was found in quantity in placer-deposita in the vicinity of Ouro Preto, in 1699, by a prospecting party headed by Antonio Dias. The name of Ouro Preto (black gold) was given because of the superficial dark coating of the gold, and the inhabitants of the district were known as mineiros (miners). Later on, the placers of Cuiaba, in the State of Matto Grosso, were discovered in 1718, and those of the State of Goyaz in 1724. All this terri- tory was at the time a private colony, but on account of its in- creasing importance it was taken over by the Crown, and in 1739 a royal governor was appointed, with his nominal capital in Sao Paulo, though for a number of years the real capital was Ouro Preto. In 1711 Ouro Preto was raised to the rank of a city, with the name of Villa Rica de Ouro Preto (" rich city of black gold ") ; and in 1720, by reason of administrative diffi- culties, Minas Geraes was constituted a separate colony from S5o Paulo, with Villa Rica as its capital. The site of this city

Gold-Field Of The State Of Minas Gerabs, Brazil. 407

was decided by the position of the gold-workings on the pre- cipitous sides of a mountain. (Fig. 10.) The wish to ex- plore, and frequent quarrels amongst themselves, caused many miners to " take to the woods ;" and in this way gold was dis- covered at Marianna, Sahara, Caethe, etc., and in 1720 at Itabira do Matto Dentro. Owing to its virgin forests, the country was at first almost impassable ; but in time it became thickly populated and most prosperous, as is proved by the ex- tensive remains of abandoned mining villages.

The Portuguese Government and the Mines. — The Crown of Portugal considered the mineral products of the country its property by royal right, and in 1700 a decree was promulgated to regulate the division of the lands and impose taxes. The auriferous ground was divided into datas or claims, measuring 80 by 40 Portuguese yards, and assigned as follows : one data to the discoverer ; one to the Crown ; and one to the mine Gov- ernor— the rest being distributed by lot. That of the Crown was sometimes sold to the highest bidder and sometimes worked for Government account. The tax, known as the quinto (20 per cent, of the value of the gold), was always a fruitful source of trouble between the miners and the Government, since, aside from the large percentage, it was collected in a very arbitrary manner by the Portuguese authorities from the owners and miners, who were generally paulistas or mineiros. (Pigs. 2 and 3.) According to official figures, the total amount of gold received by the Government on account of this tax was 7131 arrobaSy or nearly 107 tons, equal to about £18,000,000 sterling {arroba =15 kilos). The epoch of greatest prosperity was between 1751 and 1781, when the tax amounted to 100 arrobas or 1500 kilos of gold per year.

In 1810, Baron von Eschwege, a Prussian military engineer, was engaged by the Government to examine into the state of the mining industry and initiate modern methods of mining, and it is in his reports that the most reliable information of early mining operations is found. Unfortunately, the natives were opposed to systematic improvements ; but he managed to induce the Government to make laws permitting the forma- tion of national and foreign mining companies. In 1817 he commenced work at the Passagem mine, near Marianna, erect- inaf the first gold-milling stamps employed in Brazil. On the

408 aOL]>-FIBLD OF THB STATE OF MINAS GERABS, BBAZIL.

declaratioD of the independence of Brazil, in 1822, he returned to Europe, and wrote extensively of his travels, the mines, and the geological features of the district

II. Situation of the Deposits.

The auriferous zone is situated in great part on the Serra do Espinha90, which crosses the central part of Minas Geraes, and constitutes the watershed between the rivers Do5e and Sao Francisco. The limits of the gold-field are Sta. Lucia on the north, Brumado on the south, Ponte Nova on the east and Paraopeba on the west (Fig. 1.)

The diamantiferous region is situated farther north, but is also in part on the Serra do Espinha90. The district is served by the Central railway of Brazil, an excellent line of more than 1000 kilom., operated by the Government. The gauge is wide (1.6 m., 5.25 ft.) as far as Lafayette, 463 kilom. fipom Rio; but from this point onwards it is only 1 m., on account of the mountainous character of the country. The principal mines are east of the railway, and in no case more than 12 kilom. from it. The height of the country varies in altitude between 1000 and 1700 m. above tide, the two highest points being Piedade (1620 m.) and Itacolumi (1713 m.). The climate is healthy, the temperature ranging between the extremes of 36® and 8° C. The average rainfall is about 200 centim. per year, the greater part of which falls during January and February; the rainy season being from October to April, and the dry season from June to September.

m. Geological Features.

With our present geological knowledge it is somewhat diffi- cult to determine the age of the rocks of the district, though it is certain they are very old — according to Dr. Derby, of the Cambrian or Lower Silurian age. (Figs. 4, 5, 6.)

The order of the rocks as seen in the Ouro Preto district is as follows : (1) gneisses and granites ; (2) micaceous and tal- cose schists ; (3) schistose quartzites ; (4) argillaceous schists ; (5) itabirites with jacutinga (sandy micaceous iron-ore); (6) limestones ; (7) upper micaceous schists.

1. Gneisses and Granites. — These rocks appear in immense thickness at the base of nearly all the mountains of the aurif-

Gold-Field Of The State Of Minas Gbraes, Brazil. 409

erous zone, such as Ouro Preto, Gongo Socco, Cara9a, Cocaes, etc. They are often found in an advanced state of decompo- sition, but rise to a considerable height, at times — never, how- ever, forming the highest peaks. Sometimes they are aurifer- ous, as, for instance, at the Candongo gold-mines,* where grains of gold were found in the granitic mass. At other places gold has also been found in the ferruginous granites.

Dr. Derby, in his notes on Brazilian gold-ores, presented to this Institute, notices some auriferous gneiss found in the dis- trict, and carefully examined by him.

2. The Micaceous and Talcose Schists. — These vary greatly in thickness and composition, partaking of the nature of the rock beneath, and becoming micaceous or talcose, and containing mica or talc in quantity. Though in themselves not auriferous, they are often traversed by quartz-veins of varying thickness, carrying gold. These rocks are generally decomposed to a great depth, and give rise to irregular ravines all over the dis- trict, known as sbarancados. The predominant type of mica in these rocks is a finely-divided sericite, giving an unctuous aspect that has led to their reference, by most of the travelers who have visited the region, to the talcose group of rocks. True talcose schists certainly occur, but not nearly so promi- nently as has been supposed.

3. The Schistose Quartzites. — These are composed of quartz and mica, being very resistant, and with their planes of strati- fication well defined. They are often used for building pur- poses, taking the name otpedra dos lages (flagstones). At Ouro Preto they are much traversed by quartz-veins, which are auriferous, and especially so at the contact with the enclosing rock. The quartz-lode of the Catta Branca gold-mine crosses these quartzites.

4. The Argillaceous Schists. — These vary greatly in thickness, and sometimes almost disappear. In the vicinity of Ouro Preto the early miners drove through them in exploring the quartz-bodies between the quartzites and the itabirites. In some places these schists become chloritic in character, and en- close large quantities of quartz, which is generally aurif- erous.

Described in Kenwood's MetaUerous DepasiiSf pp. 175, 320. Also, Trans. Boy. Soc OonwaU vol. viii.

410 Gold-Field Of Thb State Of Minas Gbrabs, Brazil.

5. The Itahirites with JacuMnga consist of quartz (generally disintegrated) and micaceous iron-ore, in layers varying be- tween 1 and 8 centim. in thickness, with the accessory min-

FiG. 2.

wxxxamsN yxtfx XKK K xMiimuricxinii

DtftaCafr

de ouro.de quefe-tirou de quintopM a Fazcmda Real gradt oiut> e o mais fe fundio, e delle fe fez huinabmaVHpczou -=ssr- marco, onra oitav .e ptr\t9&j de ourp de vintc quccUc fc fea, cjelhe entregou naCafadc F\rr- S

Melting-House Certificate. [Translatiok : Joas Pereira de Nascimento de Joaquin Alvez has handed into this house one ounce of gold dust, which after deducting the government tax of one-fifth, one oitava and forty-three grains, has been cast into a bar, which weighs 6 oitavas 36 grains of gold of 22 carats 3 grains fineness, verified bj assay, and given to him in this melting house of Villa Rica on the 28th of April, 1809.

SOUZA. Ck)RI>OZA.]

Fig. 3.

Bar of Gold Cast in Ouro Preto in 1809. Natural Size.

erals, manganese-ore, scaly talc and iron-glance, in varying proportions. Sometimes, in this rock, the quartz is replaced entirely by oxide of iron, forming a very pure iron-ore, named

aOLD-FIXLD OF THB STATE OF MINA8 GERABS, BRAZIL. 411

locally pedra deferro (ironstone). The thickness of these rocks varies between 20 and 100 m., their outcrops, as well as parts of the surrounding surface, being often covered by a crust of iron-ore conglomerate between 2 and 10 m. in thickness, called canga. This iron formation has been proved to be slightly auriferous in many places, but the gold has only been found in payable quantities in the bands of sandy micaceous iron-ore known as jacutinga. This gold-bearing formation consists of sandy micaceous and by d rated iron-ore, associated with some yellowish talc and an earthy oxide of manganese, the whole having an unctuous touch, and running conformably to the en- closing itabiritic rock, in lines between 2 and 20 centim. thick. Though not easily distinguished from the enclosing rock by those unacquainted with the formation, the miners recognize it without difficulty. Jacutinga gold is usually of high fineness. The mines of Gongo Socco and Maquin6 are the two most im- portant which have been worked in this formation.

6. The Limestones. — These rocks are generally found imme- diately above the iron-formation, as at Ouro Preto, Gongo Socco, etc. They are usually dolomitic in character and highly siliceous, owing to the inclusion of material from the adjoining micaceous schists. There is no record that they have at any time been found auriferous.

7. The Upper Micaceous Schists. — These strata are immensely thick, and in many places are traversed by a network of small quartz-veins. They are very often auriferous, and were worked on a large scale in the early history of mining in the State. Sometimes the thin veins give place to more important bodies of auriferous ore, consisting of quartz, with large quantities of limonite.

.IV. Occurrence of Qold.

The gold occurs either in alluvial deposits or in lodes. The early miners divided the alluvial deposits into three classes : veiaSy or ri ver- washings ; iaboleiros, or lower bench-deposits; and grupiarasj or higher bench-deposits.

Of the alluvial deposits, only the beds of the more important rivers remain intact. The bench-deposits were worked out by the early miners; and the rough rubble which covered the auriferous gravel can be seen in huge piles along the slopes of the mountains and sides of the streams.

412 Gold-Field Of The State Of Minas 6Brabs, Brazil.

The lodes may be classified as contact-lodes; lodes in the schists ; lodes in the quartzites ; lines of jacutinga in itabirite.

a. Contact-Lodes. — These are situated along the Ouro Preto mountain range, stretching from about 2 kilom. W. of that city to 4 kilom. on the NE. side of Marianna; and in them the early workers probably did their first lode-mining. The most im- portant mines now working on these lodes are the Passagem and Morro Santa Anna; but Vellosa, Peluias, Tassara, etc., near the city of Ouro Preto, enjoyed in other times a certain amount of prosperity. The lodes consist of lenticular shoots of quartz,* varying in thickness from 1 to 16, and in length from 10 to 100 m., and interstratified between the itabirites and the underlying quartzites, from which, in some places, they are separated by the argillaceous schist. The shoots are much longer along the dip than on the strike, which necessitates, in mining, some unprofitable driving of levels through the hard quartzites. Some parts of the lode are richer than others, the contents varying between 2 and 200 grammes of gold per ton. This last figure is only attained when the gold is associated with a large quantity of arsenical pyrites. The average gold con- tents in working the whole of the lode vary very little, the re- sults of the working of the Passagem mine not showing more than 10 per cent, difference in the assay value from year to year. The gold is sometimes visible in the oxidized ore of the old workings near Ouro Preto. At the Passagem mine the shoots are often divided along the strike by horses of the argillaceous schist, easily mistaken for the foot-wall.

6. Lodes in the Schists. — These include by far the greater number of the known mines. They consist of lenticular shoots of quartz varying in size between the large body of the Morro Velho mine, and thin lines in many places alternating with layers of the country-rock. They follow the stratification of the enclosing rock ; and the quartz is often associated with or- dinary arsenical and magnetic pyrites, as well as limonite, and at some places, like Morro Velho, with the carbonates of lime and magnesia and iron. Sometimes large quantities of visible gold are found in the smaller lodes, though generally these rich

Dr. HuBsak foond, on examining the Passagem lode, that it contained patches of kaolinized feldspar ; and Dr. Derby has confirmed this, concluding that it is essentially a granitic apophysis.

Golb-Fibld Of The State Of Minas Oeraes, Brazil. 413

zones are not very extensive. As far as can be seen, the gold contents of the lodes are constant in depth. That of Morro Velho, for example, has been worked to a depth, on the dip, of about 1700 m. without showing any appreciable difference in size or gold-value.

c. Lodes in the QuarizUes. — These are not very important, and at present no mine is in operation upon them. The Catta Branca mine was on a quartzite lode ; but no work has been done there for the last 50 years.

d. The Jacuimga Lines in Itabirites. — These are generally not more than a few centimeters in width ; and what gold occurs in them is always coarse. In the once famous mine of Gongo Socco, and in others of minor importance, laminated masses of

jacutinga and gold have been found, weighing many pounds. The huge ravines existing along the mountain-side between Ouro Preto and Marianna are presumed to be the result of the ancient mining of B,xxnfeToxi& jacutinga in the itabirite.

V. Early Methods of Work.

When gold was first discovered, the batea or washing-pan was almost exclusively used ; but later the auriferous gravel in the stream-beds was recovered by the erection of coffer-dams at the sides and in the deeper parts, by the use of a small hand-drag. In view of the periodical heavy rains, it is probable that these methods were not very successful.

The lower bench-deposits were worked by cattas (rounded pits) dug into the gravel, with sides sufficiently sloped to pre- vent slips. The miner generally began by sinking a small test- pit; and, if this gave satisfactory results, the hole was widened out, the gravel being piled up around it. To give some idea of the importance of this work, it may be mentioned that in some places cattas were dug to the depth of 10 to 15 m. If possible, water was brought by flume to these bench-deposits, as it facil- itated greatly the uncovering of the auriferous gravel. The higher bench-deposits naturally required for this purpose the constructionof very long flumes (sometimes more than 20 kilom.). In breaking down the gravel by water-power, the gold was roughly concentrated at the foot of the hill by a series of sluices, or by large mondeos or settling-pits, some of which may still be found in good repair. All these works were necessarily sus-

414 Gold-Fibld Of Thb Statb Of Minas Gbraes, Brazil.

pended during the rainy season ; and it was the custom to clean up the concentrates when more extensive operations were pre- vented by the weather.

When the placers had been almost worked out, attention was

Section through Ouro Preto Mountain

Section through the Morro Sta. Anna and Maquine' Mountains

Section through the Go ago Socco Mountains

tuiL Gneiss or Granite

Micaceous and Talcose Schists

Schistose Quartzites

Auriferous Quartz Lode

Argillaceous Schists

2, Itabirite

Lines of Auriferous Jacutinga in Itabirite

Canga, or Iron Ore Conglomerate

Geological Sections in Minas Geraes, Brazil

called to the auriferous lodes ; and the operators, having at that time no knowledge of mining proper, treated the outcrops of these for some time as they had the alluvial deposits. The dif- ficulty of following the lodes in depth, however, obliged them

Gold-Field Of The State Of Minas Geraes, Brazil. 415

to resort to mining. Cross-cuts were run in from the hillside ; and, the lode being reached, it was excavated in irregular chambers from below upwards by a sort of overhand stoping, pillars being left to secure the hanging-wall. No timbering was employed, the levels being made with the section of a gothic arch ; and it is interesting to note that the itabirite, cut in this way, has stood unaltered to the present day. The lode- stuft was burnt, to oxidize any pyrites present; thrown into water while hot, to make it more fidable ; and then crushed by abrasion between two pieces of the hard quartzite.

In this way the whole length of auriferous ground between

Section througrh Passagem Mine

Iron Or Conglomeratt Ittbirittt

Argillaoaout Schist* Quartz Lodtt SchiVtoM Quartzilet Micacaous and Talcosa Schitts

(The strata occur in the order named, beginning at the top.)

Ouro Preto and Marianna, several kilometers in extent, was worked out above water-level by the early miners. (Fig. 11.) At some points, towards the summit of the mountain, cross-cut levels were driven ; and there is reason to believe that some of these were used as dwellings. The concentrates from both al- luvial and underground workings were treated in a sort of long tom, known as the canoa still much used by the river-washers, and consisting, in its simplest form, of a sluice about 2 m. long, and inclined at about 20°, on which is laid a blanket of native manufacture held in position by two sticks. A stream of water is allowed to run over this ; and, the concentrated auriferous VOL. XXXIII.— 26

416 aOLD-FIBLD OF THB STATE OF MINAS GBRABS, BRAZIL.

gravel being agitated at the head of the sluice, the earthy matter is carried over and the gold caught by the blanket. A final

.5 ti

o S

Co

A(l/i

n I

liK

washing in the batea of the gold caught on the blankets leaves with it only a small quantity of magnetic oxide of iron, which is separated by a small magnet

Gold-Field Of The State Of Minas 6Eraes, Brazil. 417

Figs. 12, 13 and 14 show an abandoned mine and primitive methods of working.

VI. Descriptions of Individual Mines.

1. The Grongo Socco Mine.

The decadence of the gold-mining industry towards the end of the eighteenth century was doubtless due, in great part, to the ignorance of the natives regarding proper mining methods. In 1820, an English company began to work the Gongo Socco mine ; and the great success of this first venture caused quite a

Fig. 9

Filling

Horizontal Section A- B

KSJ Filling

m; Lode

Vertical Section through Faria Mine

boom in gold-mining. Many other foreign companies came into existence, the majority of which, having been for various reasons unsuccessful, do not merit special mention. The Gk)ngo Socco mine, however, was of such importance that a short description of it may be interesting.

Gongo Socco is situated on the Central railway of Brazil, about 80 kilom. east of Sahara, and about 1000 m. above sea- level. The gold was found in jacutinga seams in friable itabi- rite rock. The mountain containing the outcrop runs E. and W., and consists of granite overlaid with micaceous schists, quartzites, itabirites, and limestones — all dipping about 45° S. This geological section, it may be mentioned, agrees well with that in the neighborhood of Ouro Preto. The auriferous jacu- tinga varied in width from extreme thinness up to 15 centim..

418 Gold-Field Of The State Of Minas Gbrabb, Brazil.

and in the wider parts the center was found to be composed in great part of laminated masses of gold, weighing firom a few grammes up to several kilos. Two-thirds of the gold extracted was found in masses, plates and threads, and one-third dis- seminated through the adjoining matrix. Captain Lyon, the manager, reported in 1830 that one man had taken out a cap- ful of stuff which yielded 10 kilos of gold. Other remarkable finds were reported as follows :

Period. Gold, kilogrammes.

From January 19 to 24, 1829, 63.8

From Febraary 26 to 26, 1829, 47,6

From September 22 to 28, 1829, 193.0

From January 21 to 22, 1830, 62.6

The whole of the itabirite formation was found to be slightly auriferous, but not sufficiently so to be profitably worked. The jacutinga seams analyzed (Henwood, op. ciLy p. 261) as follows :

Per cent

Peroxide of iron, 97.00

Silica, 1.60

Alumina, 1.10

Oxide of manganese, 0.60

The richest part of the mine, known as the eastern shoot, seems to have furnished the greater part of the gold. Ap- parently the mine was not rationally worked, the absence of all filling rendering the consumption of wood enormous. The most resistant timbers were crushed by the pressure of the friable itabirites, and had to be renewed continually. The richer portions of the auriferous seams were simply washed in the batea and the " run of mine " was put through the mills. These were of native manufacture. The stamp-heads and dies (made in the Catalan forges near by) weighed 130 kilos each, and ran at 60 blows per minute, crushing 3 tons of ore per head per day. The gold was collected on strakes covered with uncured hides and laid at an inclination of 7 per cent., the concentration being finished, as usual, by hand in bateas.

This mine was sold to the English company for £90,000; and notwithstanding the high price, and the almost proverbial extravagance and robbery attending the operation, it was very prosperous for a time. Between 1826 and 1839 eleven tons of gold (worth £1,300,000) were taken out. Dr. Gardner, a traveler

Gold-Fibld Of The State Of Minas 6Eraes, Brazil. 41

Fio. 10.

The City of Ouro Preto, Brazil.

Fig. 11.

Old Open-cast Gold- Workings, Ruins of Villa Rica in the Distance.

420 Gold-Field Of Tub State Of Minas 6Erabs, Brazil.

Tig. 12.

View of the Crush of 1845, which Caused the Abandonment of the Catta Branca Mine.

aOLD-FIELD OF THE STATE OF MINAS GERAES, BRAZIL. 421 Fig. 13.

The Pary Mine, Native Mill.

Fig. 14.

The Pary Mine, Amalgamating Plant.

422 Gold-Field Of The State Of Minas 6Eraes, Brazil.

visiting the mine in 1840, found the two lower levels under water ; and it is more than probable that the lack of proper pumping-applianees was finally responsible for its shutting down.

Table I. gives the yield in gold from 1826 to 1856.

Table I. — Productiov of Gold at the Gongo Socco Mines 1826-1856.

Gold Prodvction.

Depth of Mine.

At the Wosh-

At the

Total.

Year.

Xo. of Men.

ing-House. Kilos.

Stamp-mill. Kilos.

Fathoms.

Kilos.

1,421

1,564

1,047

1,185

1,132

1,029

1,568

! 447

1,115

' 268

j 198

Total

8,725

4,162

1 12,887

Mode

ni Mines.

The most important mines in operation at the present time are as follows :

(1) Morro Velho, owned by The St. John del Key Gold Min- ing Co.

Brazil. 423

(2) Passagem, owned by The Ouro Preto Gold Mining Co. Pigs. 7 and 8.

(3) Faria, owned by The Faria Gold Mining Co. Fig. 9.

(4) Sao Bento, owned by The SSo Bento Gold Estates Co.

(5) Sta. Quiteria, worked by The Anglo Brazilian Gold Min- ing Co.

(6) Morro St. Anna, owned by The Ouro Preto Gold Min- ing Co.

(7) Itabira, owned by Companhia Braziliera das Minas de Itabira.

(8) Carrapato, worked by Carrapato Gold Mining Co.

(9) Juca Vieira, owned by Lathom Gold Mining Co., Ltd.

(10) Florisbella, owned by Companhia Aurifera de Minas Geraes.

The companies Nos. 7 and 8 are native; all the rest are English.

(1) The Morro Velho Mine.— The St. John del Rey Gold Mining Co., Ltd., was originally formed with a capital of £165,000 to work a property near the town of that name. In 1834 this property was abandoned and that of Morro Velho acquired. The Morro Velho lode is in the form of an oval column, and consists of quartz, magnetic iron pyrites, calcite and dolomite, with some pyrites and mispickel. It runs down in the midst of (according to Dr. Derby) a highly sheared calc schist, with a dip of 45°, an E.-W. strike, a thickness varying between 1 and 35 m. in width, and a length of more than 170 m. It appears to have been worked from the very earliest times, although the only reliable information concerning it dates from the end of the eighteenth century, when it was worked by a Catholic priest, named Freitas. It gave very good results ; but, like the ma- jority of the native mines, it was, by reason of the ignorance of rational mining methods, stopped early in the last century. Auguste de St Hilaire, the famous French traveler, passing, in 1818, through the village of Congonhas, now known as Villa Nova de Lima, wrote in his Journal :

'' Congonhas doit sa/ondation a des mineurs aUiris par Vor que Von trouvait dans les aUnUmrSj et son hidoire est edU de taiU d'autres bourgades. Le preeieux metal s'est epuisS, les traaiux sont devenus plus difficUes, et Congonhas announce actueUement que la dioadence et Pabandon,**

This conclusion was somewhat hasty, for the history of Morro

Velho during the last 70 years has proved that the former aban- donment of amine in Minas Geraes does not by any means prove that it was worked out. The early work of the English company which purchased the mine in 1834 simply followed the method of its predecessor, and resulted in the formation of an immense chamber, the hanging-wall being held up by huge timbers and pillars of low-grade ore. In 1867 a fire caused heavy falls, which resulted in the temporary abandonment of the mine. During this first period the mine produced about 28.5 tons of gold from a mineral assaying 26.5 grammes per ton, of which only 15.5 grammes were recovered. On the paid-up capital of £185,000, the dividends between 1842 and 1867 were at the rate of 25 per cent, per year, a total amount of £896,000 being distributed. Later, it was decided to reopen the mine ; and to this end the capital was raised to £288,000, and two vertical shafts were sunk to the lode. These were completed in 1874, but the system of work followed was little better than before. It consisted in leaving pillars of low-grade ore, or, when this was not possible, putting in huge stuUs to hold up the hanging-wall. As the mine became deeper the pressure on the timber increased enormously, and the stulls were crushed daily. During 1886, the pressure became so great that a part of the hanging-wall fell, destroying the mine again. From the date of the reopening to the time of the crush, 80 tons of gold had been produced, and between 1875 and 1884, dividends amounting to 80 per cent, per annum were declared, a total amount of £556,600 being distributed. The total value of the gold extracted from 1834 to 1884 was £5,500,000.

After this new disaster, the present manager, Mr. Chalmers, suggested the reopening of a new mine below the old one; and two vertical shafts were sunk, 17 m. apart and 48 m. from the lode, in order to keep the exit safe in case of accident. They were completed in about 3 years to the depth of about 686 m., a rate of 24 m. per month being attained. An adit-level 364 m. long, crossing the shafts 98 m. from the surface, was run for connection and haulage. In the first part of the adit-level, and for 45 m. in the shafts, the enclosing schist was decomposed and soft, so that lining was indispensable. All drilling was done by hand, machines not proving successful, by reason of the nature and dip of the rock.

Gold-Field Of Thb State Of Minas Oerabs, Brazil. 425

It was decided to adopt in the new mine overhand stoping and filling. Prom the shafts, levels are run the entire length of the lode, and connected vertically by winzes.

Owing to flattening of the lode, underlie-winzes have been adopted, which follow the course of the lode. The whole width of the lode is excavated to the height of about 5 m., after which the level is arched over with brick and concrete. Over- hand stoping is then carried on, filling being introduced regu- larly, to keep the men up to the working-face. The filling from the surface was first raised into the stopes by the heavier de- scending mineral, actuating a counter-balance hoist governed by a friction brake ; but now suitable double- and single-drum engines are employed for hauling and winding. It was the custom at one time to return the ore, after treatment, to the mine as filling ; but the oxidation of the pyrites generated so much heat that this practice was abandoned. It is an interest- ing fact that while, in the old mine, water constituted one of the chief difliculties of working, the present mine is perfectly dry.*

To the unwatering of the old mine, which contained at times more than 20,000 tons of water, Mr. Chalmers, the manager, early gave particular attention. At first he employed a bailing arrangement, but as this only handled the water above the crush, he proceeded to erect hydraulic machinery to unwater the old mine through the new one. The hydraulic arrange- ment for actuating the pumps is driven by water brought down the shaft to the adit-level in a 30-centim. pipe, under a head of 150 m. The pump-rods are 16 centim. in diameter at the top and 11 at the bottom, and their total length is 652 m. The counter-balance boxes carry 85 tons each, the total weight of the pump-rods, etc., being calculated at 70 tons. The pump makes 6 strokes of 3.3 m. per min.

The tapping of the overlying body of water was eflfected by an air-driven diamond drill, fixed in a specially-designed can- non, which permitted satisfactory drilling, while at the same

The impoitanoe of this fact cannot he overestimated, as although in the deeper levels the cost of haulage will increase, that of pumping decreases. It is interesting to note that in this respect this Brazilian mine is similar to those in the Transvaal, according to Mr. J. Hays Hammond in his paper on "Gold Mining in the Transvaal,'' Trans., xxxL, 817.

426 Gold-Field Of The State Of Minas Gebabs, Brazil.

time guarding against disaster due to an unexpected in- rush of water. From a dead heading on the sixth horizon, 4 holes of an average length of 41 m. were driven upwards to where the old excavation was supposed to exist. They trav- ersed, for the most part, ore and micaceous schists, but none of them cut into the old mine. The progress of the drill varied greatly : in pure quartz it did not exceed 5 centim. per day, though in the schists sometimes as much as 4.5 m. were drilled in 24 hours. The fifth hole encountered water 96 m. from the stuffing-box, in May, 1896 ; the pressure verified on that occa- sion being 45.5 kilos per sq. centim., or 629 lbs. per sq. in. In a comparatively short time the water was emptied down to the bore-hole; and in July, 1901, the old mine had been com- pletely drained, and was kept well in hand by the pumps.

Except in the case of the enclosed electric-motor fans, which are placed in permanent roadways, and consequently in pro- tected positions, all power underground is given by air com- pressed at the mouth of the adit. This general substitution of compressed air for electricity (first used) was made (though the compressed air is the more costly of the two) on account of the electric motors which were installed being affected by the heavy blasting-operations.

The winding-engine is a hydraulic one, driven by hurdy- gurdy wheels under a head of 60 m. Although originally de- signed for an output of 6000 tons per month, it is actually handling more than double that output. The drums are par- allel, 3.35 m. in diameter, and the rope is a 2.5-centim. "lock coil."

The journey in the shaft occupies about 2.5 minutes. The stone leaves the adit in the cars which are filled in the stopes. They are taken up an endless-chain incline, and, after weighing, are discharged by a tipple to a 7-centim. grizzly, the large pieces being picked off and thrown into a large Blake-Marsden rock-breaker. The broken stone, together with that from underneath the grizzly, enters a trommel with 5- centim. holes ; and the fine ore passing through this goes direct to the bucket-elevators. The coarse stone falls upon a revolv- ing-table, where it is picked over by women, the rejected pieces being placed on the extreme edge, and, as the table revolves, swept off into a car which goes to the dump. The good min-

Gold-Field Of Thb State Of Minas Gbrae8, Brazil. 427

eral is raked off into three small Blake-Marsden rock-breakers, with apertures 85 mm. wide, and from these it passes by chutes to two bucket-elevators, which deliver into a saddle-back car. This latter distributes the ore to the storage-bins, which are of the usual type, fitted with " Challenge " feeders. The mill constructed by Messrs. Fraser k Chalmers has 120 stamps, weighing 840 kilos each. The drop and speed vary according to the class of ore, but may be taken as averaging 20 centim. drop and 90 blows per minute. From 2.5 to 8.25 tons per head are crushed per day, or say 10,000 to 13,500 tons per month. The mortar has a double discharge, through a 60-mesh gauze, the screens being corrugated, to give strength and larger area. The pulp leaving the screens passes into distribution- boxes, which deliver it by spouts, through which the feed can be regulated, to the three-decker strake-frames. These are hung on centers over a sloping cement floor, on which the con- centrates fall as the mechanical washer removes them from the canvas. This washer is a traveling siphon, which tilts the frame from the horizontal to the vertical position, and, by means of a row of flat jets, completely cleans each strake in a few seconds, the supply of pulp being automatically cut oft' while the strakes are being washed. By this arrangement one man and two boys can attend to some 80 frames, arranged in two lines. The tailings from the first row are led by pipes to the second row, while the concentrates run off the floor and are led away to be treated on similar strakes at a lower level, until the bulk is reduced to about 1 per cent. The concentrates from the second row are reserved for further treatment by the " oxygen " process, while the slimes, which constitute 70 per cent, of the total weight, are rejected. The rich concentrates (formerly treated by barrel-amalgamation) are now passed over small tables, until the gold is sufficiently pure for melting into bullion. The mechanical arrangements and general plan are such that all these operations of concentration are carried out with the minimum expenditure of power and labor. About 65 per cent, of the gold-contents are removed mechanically, and 15 per cent, by the oxygen process, the remaining 20 per cent. being at the present time lost, though it will be treated in the future, if the value of the mineral remains the same.

The " oxygen " process was elaborated by Messrs. Chalmers

428 Gold-Field Of Thb State Of Minas Oerabs, Brazil.

& Wilder at Morro Velho, after they had tried other well- known processes and found them inapplicable to this refrac- tory ore. The writer is not permitted to make public the de- tails of this process ; but it may be described briefly as a modification of the cyanide process, with agitation and air forced through the liquid to facilitate the solution of the gold.

All the machinery connected with the mill is driven by a Pelton wheel 2.36 m. in diam., actuating a wire rope 2 centim. in diam., which travels at a velocity of 1600 m. per minute. The tension on the rope, usually obtained by a guide pulley at the expense of much loss in friction and damage to the rope, is in this instance effected by the Pelton wheel, with its driving-pulley, being mounted on a sliding bed-plate, and the water-jet being telescopic. By simply releasing a few bolts holding the bed-plate and actuating a screw, any required ad- justment can be attained for the requisite tension on the rope.

Power for driving the machinery at the mine is obtained :

1st. By the utilization of power from the water-courses (60 miles in extent) bringing water direct to the plant

2nd. From three electrical transmission-plants, two of which are continuous-current, transmitting 250 H. P., and one high tension three-phase, transmitting about 150 H. P.

8rd. From semi-portable steam-engines, using wood as fuel, and only employed when the supply of water falls off.

The three-phase alternating-current has proved much more satisfactory than the continuous-current ; and it has now been decided to lay down an additional high-tension three-phase plant of about 300 H. P. It was at one time intended to trans- mit at low tension ; but this had to be abandoned, on account of the cost of the copper cables. Another more important scheme, to transmit electrically about 1500 H. P., has been left in abeyance for the present, owing to the necessity of hav- ing as soon as possible an increase of power to take the place of the steam-engines. The superintendent, however, is of opinion that the scheme must eventually be carried out, if the mine is to be worked to a great depth economically, and all hand-drilling replaced with power-drills. The cost per H. P. per day, with wood as fuel, is 2. 3., and with water, only 3rf.

The ore is very irregular in its gold-contents. The pure quartz is seldom auriferous, and the pure pyrites (unless it be

Gold-Field Of The State Of Minas Geraes, Brazil. 429

arsenical) hardly ever rich. A mixture of quartz with arseni- cal pyrites and pyrrhotite, in the presence of the carbonates, dolomite, etc., seems to be the most favorable matrix for the gold. The enclosing rock, though generally pyrites-speckled, contains only a small quantity of gold at the contact, equivalent to about from 3 to 5 grammes per ton. Although Henwood declared that the ore became poorer in depth, this has been proved to be a fallacy by the results obtained since the reopen- ing of the mine. They compare favorably with those of 1858 and 1860, which may be considered as typical, and in which the assay-value ran from 20 to 28 grammes per ton of ore, the extraction then being 11 to 18 grammes per ton, or about 60 per cent, of the gold-contents. An analysis of the ore gives the following result :

Per cent.

Silica, as quartz, 24. 10

Iron, in pyrites, pyrrhotite, etc., 31.47

Arsenic, in mispickel, 2. 32

Sulphur, in pyrites and pyrrhotite, 13.52

Alumina, in clay-slate, 3.00

Oxide of manganese, 1.30

Lime, in dolomite, calcite, etc., 3.08

Magnesia, in dolomite, etc., 6.51

Copper, in copper pyrites, 21

Carbonic acid and oxygen in dolomite, etc., . . . .14.49

The proportion of pyrrhotite or magnetic pyrites in the ore averages 28.5 per cent. The bullion is worth 645. to 705. per ounce, and is .790 to .810 fine, the rest being silver.

The consumption of lode-ground per annum is about 30 m. of vertical height. For the year ending March, 1900, the average yield was about 28 grammes of bullion per ton, equiv- alent to 585. 2.5d., of which 4l5. 5.5rf. was recovered on the strakes, and II5. 9d. by the oxygen process. The cost of ex- traction for the same period was 3l5. 11.25rf., made up of 255. 2.5rf. for working-cost, and 65. 8.75d. for plant-renewals. The recovery was 81 per cent. For the year ending March, 1901, the value of the gold extracted per ton of ore was 465. 6.5cf., of which 375. 3.75d. was recovered by the strake process, and 95. 2.7 bd. by the oxygen process. The total cost of extraction was 305. 5.5rf., of which 255. 1.5rf. was working-cost, and 55. 4rf. plant-renewals. The working-cost may be divided as follows :

430 Gold-Field Of The Stats Of Minas Qbrabs, Brazil.

Mining department, Beduction department, . Engineer's department, . Stores, offices, etc., .

s.

d.

25 1.5

The somewhat lower results of 1901 are due in a great meas- ure to a barren piece of lode which replaced the rich ore be- tween the eighth and ninth levels. This occurrence is not of very great importance, since the same thing happened in 1882 at a higher level.* The ore has already been found to be of average value below the tenth level; so that there is little doubt of its continuing normal in the future. Another fact that contributed to the lower yield was the smaller percentage of ore rejected at the mill, namely, only 4.6 per cent., as against 7.4 per cent, in 1900. In every other respect the year ending March, 1901, was a record one; 152,238 tons of ore being raised, and 140,855 tons crushed, and the extraction amount- ing to 99,197 oz. Troy, equivalent to £327,663, or an average of 0.7 oz. Troy per ton of ore.

Some time ago an underlie-shaft was started to follow the lode along its dip, and serve for hauling from the lower levels. It has been found, however, that the inclination of the lode has become appreciably less, and consequently the shaft would, if continued, run into the lode. It will now only be used for handling the ore down to the twelfth level, and a hauling-level and vertical shaft will be made to handle the ore from all levels below that. The total depth of the mine from the mouth of the shaft to the twelfth level is 1030 m. The large ore-body and its uniform quality, together with the present excellent manage- ment, augurs well for tho future of this mine, which is a model of its kind, and a monument to the engineering skill and or- ganizing ability of Mr. Chalmers.

(2) The Passagem Mine. — This mine (Figs. 7 and 8), belong- ing to the Ouro Preto Gold Mining Co., and situated about 7 kilom. E. of Ouro Preto, is the one which Von Eschwege worked early in the eighteenth century. The ore occurs in shoots of

The distinguiBhed American GeologiBt, Dr. Orville A. Derby, who has made a life-study of Brazilian mineral formations, is distinctly of opinion that there has been no evidence as yet of the lode pinching out.

Gold-Field Of The State Of Minas Gbrabs, Brazil. 431

quartz and arsenical pyrites, with smaller quantities of magnetic and ordinary pyrites, intercalated between friable itabirite on the hanging-, and schistose quartzites on the foot-wall. The latter are sometimes interposed in the lode, and occasionally replace it altogether. The lode strikes NE.-SW., dips 20° SE., ranges in thickness between 2 and 15 m., and contains varying propor- tions of gold. Near the foot-wall, where arsenical pyrites and tourmaline abound, it runs as high as 200 grammes, while the poorer ore yields only 2 to 3 grammes, of gold per ton. Min- ing is now done through two inclines sunk on the dip ; and a third, approaching completion, will open up the lower and more easterly part of the main shoot. The levels, 16 m. ver- tically (or 50 m. on the dip) apart, are run along the hanging- wall of the ore-bodies. The ore is extracted from overhand stopes, afterwards filled with material from the schistose quartzites, a considerable quantity of which is necessarily broken down in the ordinary operations of mining. In order to let the filling rest directly on the foot-wall, it is the custom first to mine, by underhand stoping, the triangular piece of ore below the level and between it and the footrwall ; after which, the lode is taken out to the full height of the level from hang- ing- to foot-wall. The foot-wall side of the level is then built up, roads being left to the foot-wall, at intervals, for the extraction of the stone from the stopes below. Stoping is then carried upwards (chutes and pockets being made in the filling for the ore excavated) till a height of 8 m. is reached, when another small road is made to the foot-wall, and the second half of the stope is worked out in the same way as the first. This double handling of the ore from the upper half of the stope is necessary because the inclination of the lode is not great enough to enable the ore to fall by gravity to the tramming-levels. All the roads, chutes, pockets, etc., are built of the stone from the schistose quartzites. This system of filling, introduced by the superintendent, Mr. Giffbrd, in place of the old chamber-and-pillar system, which left the worked-out parts of the mine often in a dangerous state, has been found economical and satisfactory, dispensing altogether with the use of timber in the mine. Where the lode is very wide, the filling and piling becomes somewhat expensive — waste material having to be brought from the more distant

432 Gold-Field Of The State Of Minas Gbraes, Brazil.

parts of the mine. In the tramming-levels a narrow-gauge track (40 centim.) is used, which permits the introduction of very sharp curves, necessitated by the irregular-shaped ore- bodies. Air power-drills are used in driving the levels, but hand-drills do better in the stopes. The ore trammed from the levels is fed into pockets over the inclined shaft, and from there hauled to the surface. The lowest levels are now some 600 m. below the surface, along the incline ; and 6000 tons per month are excavated, carrying from 12 to 15 grammes of gold per ton.

This ore must be classed as refractory, the gold being con- tained mostly in arsenical pyrites. The mineral is trammed from the shaft-mouth to the picking-floor, where about 10 per cent, of the rock is rejected. The rest passes through Blake crushers, and is then distributed to an 80-stamp Californian mill. The pulp from the batteries is passed over a short length of blanket-strakes, to retain the rough free gold, and over 32 Frue vanners, which separate the pyritic concentrates containing the finer gold. Owing to the arsenical nature of the pyrites, amalgamation was very unsatisfactory and had to be aban- doned. The product from the blanket-strakes is re-concen- trated to a small bulk, and the rough gold is separated in bateas. All the residues from the re-concentrates and from the bateaSy together with the concentrates caught in the Frue van- ners, are then roasted in reverberatory furnaces, and the gold is extracted by the barrel-chlorination process. By reason of the high cost of roasting, cyaniding, without roasting the raw concentrates, was attempted, but for a long time without satis- factory results. Recent trials of a modified cyanide process, including agitation, have had much better success ; and the latest information indicates that, in the near future, this pro- cess will replace chlorination.

For the year ending June, 1900, the yield in gold-bars from 63,644 tons of ore was 11.3 grammes per ton, as against 9.45 grammes for the previous year; or, expressed in money-value, 265. 10.5rf. as against 225. 3.5rf. per ton. The total extraction was 83.3 per cent. The expenses per ton of ore increased dur- ing the same period (largely, however, by reason of a rise in Brazilian exchange) from 205. 8d. to 225. 6d. The cost of treating the ore during the year under consideration was di- vided as follows :

Gold-Field Of The State Of Minas Gerabs, Brazil. 483

Cost of Treatment per Ton of Ore June, 1899, to June 1900.

AdminiBtration, 0 6

Mlniog, including development, 13 I

Milling and concentrating, 3 11

Gblorination, 1 10

Gold-tax, 11

Maintenance and repairs to plant, 15

Incidental expenses, 0 8

22 6

From April, 1884, to December, 1900, the yield of 617,129 tons of ore treated was 6,862,572 grammes of gold, an average of 11.12 grammes per ton.

During the year ending Dec, 1901, profits were diminished by the increase in the value of the National currency (in which, of course, expenses were mostly paid). The gold-value ex- tracted was 275. 2d. per ton, as compared with 265. 10.5rf. for the previous year ; but the cost, by reason of the higher ex- change, was 255. 2d. as compared with 225. Qd. per ton.

(3) The Faria Mine. — This mine (Fig. 9) is situated near the station of Honorio Bicalho, on the Central railway of Brazil. The ore-body ia a chimney or oval column, like that at Morro Velho, intercalated between micaceous schists. It strikes NE.- 8W., dips 60° BE., is from 2 to 10 m. wide and 50 m. long, and consists of quartz and auriferous pyrites, with a certain amount of hydrated oxide of iron and argillaceous schist. An incline following the dip, sunk in 1897, has reached a vertical depth of 150 m., or 250 m. on the incline. The hoisting is eftected by electrical power. The mine was opened up by levels run in along the center of the lode from end to end, and connected by rises. Overhead stoping followed, the ore being taken out in slices about 2 m. thick. The friable nature of the hanging-wall makes it necessary, sometimes, to work the slice in sections, with filling introduced from outside, and kept tightly packed up — only a road being left along the foot-wall to serve as communication from one part of the stope to the other. Powerful pumps, with cylinders 35 centim. in diam. by 2.1 m. stroke, working at 7 strokes per minute, were erected when the shaft was sunk, and were able at the time to handle all the water ; but as sinking has gone on, the quantity has so increased as to overpower them at times. An adit-level, which will serve

434 Gold-Field Of Thb State Of Minas Gbraes, Brazil.

to drain the mine, will probably be driven in the near future to a point on the lode 100 m. below the present working-level.

The method of reduction first adopted was almost identical with that in use at the Passagem mine ; but after a little expe- rience in milling the ore it was found that, although it con- tained from 20 to 25 grammes of gold per ton, only about 48 per cent, of this was extracted, by reason of the argillaceous char- acter of the gangue and the consequent formation of a large quantity of slimes which carried off the gold. To remedy this trouble, a cyanide-plant was erected to treat the tailings by per- colation, and the slimes by Johnston filter-presses and agitators. This process has given satisfactory results, though some diffi- culty has been caused by slow filtering. The j)ulp is first passed over amalgamated plates, and then into two spUzlutten, which separate the concentrates from the tailings, the former going to boxes. The contents are allowed to dry somewhat be- fore being cyanided. The tailings are passed through 2 spitz- kasteny which separate the slimes ; and these pass to settling- tanks for treatment by the Johnston filter-press process, the tailings, together with the concentrates, being treated by the ordinary percolation process. The writer is informed by the present manager, Mons. A. Triana, that good results are ob- tained— the extraction of gold per ton for the month of No- vember, 1901, having been as follows:

Extraction per Ton.

Per cent.

On the amidganiated plates, 29.08

Bj the cyanide percolation process, 51.62

By the Johnston filter-press process, 4.57

Total, 85.27

The extraction by the cyanide treatment reached 90 per cent, on the sands and 55 per cent, on the slimes; and the propor- tions of concentrates, tailings, and slimes may be taken as 20 per cent., 30 to 35 per cent, and 45 to 50 per cent, respec- tively.

(4) The Sao Bento Mine. — This mine is situated near Santa Barbara. The lode, which is intercalated in the micaceous schists, is composed of a series of shoots which outcrop for 2

Gold-Fibld Of The State Of Minas Geraes, Brazil. 485

miles along the ridge of the S5o Bento moantain. It strikes NE.-fiW., and dips 66° SE. The lode-matter is siliceous mica- ceous iron-ore, with interstratified bunches of schist, ferrugi- nous quartz, earthy iron-ores and limonite. It is about 13 m. wide, and although all of it carries low values in gold, only from 0.5 to 2.5 m., containing from 8 to 80 grammes per ton, is available for milling. The pay-mineral is found in one or more branches in the lode, the highest values being in a ferru- ginous saccharine quartz in the higher levels, and associated with arsenical and ordinary pyrites in the lower levels — the former being, no doubt, a result of the decomposition of the latter. Owing to the irregularity of the pay-ore, frequent assays are necessary to control exploitation.

Since the lode stands in a hill of considerable height, it has been possible to mine it hitherto by cross-cut levels, driven from the hillside, about 80 m. apart, vertically. Overhand stoping and filling is practised ; and the ore is trammed to the mill situated at the foot of the valley.

The oxidized character of the ore, the argillaceous gangue and the finely divided state of the gold would probably cause, in any treatment by a wet process, the formation of a large quantity of slimes. Hence a plant was erected for dry-crushing and direct cyanide-treatment. The ore is passed through Blake crushers and Gates rolls, and, after drying in a revolving dryer, passes through a mesh-opening of 1.5 mm. This coarse crushing has given satisfactory results, the extraction being about 86.6 per cent. It is open to doubt whether the process will work equally well with the sulphide-ore which will re- place the oxidized mineral in the lower levels, though it has been found that the small quantity of sulphides encountered at present has no appreciable eflfect on the percentage of gold extracted. The average yield of gold per ton of ore, since the commencement, has been 18 grammes, equivalent to 32. 4d.

Owing to the short time that mining operations have been carried on, and the consequent small output, the costs per ton of ore treated are somewhat abnormally high, as the following statement shows :

VOL. xxxni.— 27

436 aOLD-FIELD OF THE STATE OF MINAS GBRABS, BRAZIL.

Cost of Treatmmt per Ton of Ore.

AdminiBtration, 4 0

Datj and charges on gold, 1 11

Mine-deyelopment, 4 10

Stoping and mine-maintenance, . . , 10 7

Transporting ore to mill, 0 9

Milling (steam-power), 2 10

Cyaniding, 3 0

Maintenance, 15

Total 29 4

The production of the mine has hitherto been about 1500 tons per month ; but this will soon be increased to 3000 tons or more, and the costs per ton will consequently be appreciably diminished.

Although the use of steam-power, from wood as fuel, is often convenient and economical during the opening of a mine, it constitutes afterwards an ever-increasing expense, in consequence of the progressive exhaustion of timber in the vicinity. The cost of wood at the SSo Bento mine is now about £80 per month ; and it is therefore proposed to replace steam with power transmitted electrically from a neighboring waterfall.

(5) The Sta. QuUeria Mine. — This mine is situated a short distance from the SSo Bento. The lode is composed of limon- ite and quartz, and resembles that of 83o Bento, of which, in fact, it seems to be a continuation. It is interstratified between the talcose and graphitic schists, strikes NE.-SW., dips 45° SE., and varies in thickness between 2 and 10 m., of which only about 2 m. is pay-ore. The mineral is distributed ir- regularly in the lode. The ore of the highest value is a con- cretionary limonite, no doubt a product of the decomposition of pyrites which will be encountered at a lower level. The method of working hitherto pursued has been to follow the richer lines of the lode by means of levels extended from the hillside, in order to avoid the expense of haulage and pump- ing,— ventilation being effected by air-shafts to the surface. Hauling- and pumping-plants are now building, for the purpose of working below drainage-level. The mineral is trammed from the mine to a lO-stamp California mill, which (by reason of the friable character of the ore) crushes as much as 4 tons per head per day. The pulp is passed through a 80-mesh

Gold-Field Of The State Of Minas Geraes, Brazil. 437

screen, which has been found sufficiently fine to get a satisfac- tory extraction, while avoiding the formation of slimes. The gold is recovered by amalgamation with copper-plates in the mill and outside on tables. Of the copper-plates on the tables, two are silver-plated and two plain. Comparative tests, under similar conditions, show that the silver-plated plates give the best results* The tailings from the tables are passed over blanketstrakes, to separate any gold not caught on the tables, and the blanketconcentrates are treated by barrel-amalgama tion. The complete process gives an extraction of about from to 90 per cent., divided approximately as follows : 40 per cent, inside the mills, 35 to 40 per cent on the tables, and 5 to 10 per cent on the blanket-strakes, the total recovery being about 14 grammes of gold per ton of ore. The output of the mine is at present only about 1200 tons of ore per month, but it will soon be largely increased by an inclined shaft, which it is proposed to sink to the deeper levels.

(6) Morro St Anna and Maqumi Mines, — company was formed in 1862 to work the Morro St Anna property, situated near Marian na. The lode carries quartz, with arsenical and or- dinary pyrites, and occupies the same geological position as that of the Passagem mine, distant about 6.5 kilom., of which it is supposed to be the continuation. Soon after it was opened a rich outcrop was discovered near by, at Maquine, where the gold was found to be contained in jacutinga lines like that of Oongo Socco. This auriferous ground had a strike of NE,- SW,, and an inclination of 27° SE. Although it carried values over a width of from 10 to 20 m., the greater part of the gold was contained in a few thin seams oi ih jacutinga ore. During 1868, two and a half tons of gold were extracted (one lot of 108 tons of ore gave 127 kilos of gold), the average gold-value of the ground being about 15 grammes per ton. In 1867-68 the company distributed over 100 per cent, in dividends; but shortly afterwards difficulties were encountered in working the mine, owing to the friable character of the itabirite and the lack of a proper filling system to counteract it StuUs of huge -dimensions and of the most resistant wood were easily crushed by the non-cohesive mass of hanging-wall. Moreover, the mine was very wet, and, in the absence of adequate pumping machin- ery, was inundated several times. It was finally abandoned, at a

438 Gold-Field Of The State Of Minas Qbraes, Brazil.

depth of 212 m. on the dip. The rich gold-bearing seams which were distributed at the surface throughout the lode, had shown a tendency to concentrate in depth. This mine had much in common with Gongo Socco ; indeed, the history of one may be taken as that of both. They were the only two jacutinga mines successfully worked by English capital.

Upon the abandonment of the Maquine mine, attention was. again directed to the original Morro St Anna property proper; and, for the treatment of the ore, a plant, consisting of 20 Cali- fornia stamps, with Prue vanners for the concentration of the sulphurets, was erected ; also a 5-ton Plattner.chlorination-plant. Unfortunately, the capital of the company was not sufficient to- develop the mine satisfactorily, and it was sold to the Oura Preto Gold Mining Co., which is now taking steps to open up the large quantity of ore known to exist above water-level. The value, thickness, length, etc., of the lode are much the same as- those of the Passagem mine, already described.

(7) The Itabira Mine. — The General Brazilian Mining Asso- ciation was formed in 1868 to acquire, near the city of Itabira do Matto Dentro, three properties, all of which had been worked with great profit during the eighteenth century. The principal mine is that of Itabira, in which the gold is contained in thin seams of auriferous jacuiingay interstratified between the siliceous iron-schist and an enormous mass of massive ita- birite, which forms the summit of the Pico de Itabira. The seams outcrop near the summit of the peak, strike NE.-SW.,. and dip 30° SE., gradually flattening in depth.

The above-named Mining Association did not succeed in reaching the auriferous seams, and went into liquidation in 1874, when the property was acquired by some of the original owners, who continued the work and crossed the seams a few months later. In 4 months thereafter, the small force em- ployed extracted 20,626 oitavas (2,292 oz. Troy) of gold, worth £6000. Unfortunately, a heavy fall of rock in the shaft stopped operations, and the mine was abandoned.

The gold was nearly all found in very rich stringers of jacvr- tinga the ore from which was treated on small canvas strakes and in bateas. The poorer parts of the seam were treated in a stamp-mill of native manufacture.

The mines are now being worked by a syndicate; and a.

Gold-Field Of The State Of Mina8 Gbraes, Brazil. 489

shaft is being sunk with the intention of cutting the seams of jacutinga in depth.

(8) The Carrapato Mine. — This mine is situated near Caethe. Its lodes are for the most part of quartz and auriferous arsenical and ordinary pyrites, interstratified between talcose schists. The strike is about E.-W., and the dip 89°.

The highest gold values are found in a series of lenticular masses of quartz, varying in thickness from 0.5 to 8 m., and often containing visible gold at the contact with the country- rock, and samples from these taken by the writer gave 78 grammes per ton of ore. The largest lode, varying in thick- ness between 2 and 5 m., assayed, in an average sample, 12 grammes per ton.

(9) The Juca Vieira Mine. — This mine is near the last de- scribed; and its gold-bearing formation has much the same character, though it contains more visible gold and some sul- phide of antimony. It is at present worked by the Lathom Gold Mining Co., which is erecting machinery for the econom- ical treatment of the mineral.

(10) The FlorisbeUa Mine. — This mine is near the station of Honorio Bicalho. It has several lodes of quartz, interstratified in the micaceous schists, striking N"E.-SW., and dipping 45° S£. A sample taken from a shaft running through one of the shoots gave the high gold-contents of 157 grammes per ton; but the general run of the ore varies only between 8 and 20 grammes.

Note. — AU the lodes in the last three mines have a tendency to be " bunchy," very rich mineral being found in places, while the average of the ore runs between 10 and 15 grammes. Al- though the lodes seem to be fairly constant in depth, their longitudinal extension is generally not very great.

Vn. River-Dredging.

A detailed investigation of the alluvial deposits and the old methods of working them has made it clear to the writer that the important deposits in the beds of the rivers are to all intents and purposes still virgin. To the early explorers, the task of exploiting the beds of rivers was well-nigh impossible ; but to- day there is nothing to prevent the overcoming of all difficul- ties by up-to-date machinery.

440 Gold-Field Of The State Of Minas Gbrab8, Brazil.

Gold, undoubtedly, exists in considerable quantity in the beds of the rivers. Almost everywhere, the faiscadores {batea washers) gain a livelihood by working the river banks during the dry season, and coffer-dams, constructed in the shallow mar- gins of the rivers, enabled the early miners to get at some of the gold. In the majority of cases, however, three-fourths of the total area of the river-beds remained untouched.

The writer is decidedly of opinion that river-mining would be profitable, if carried on with the aid of suitable modern machinery. Owing to the depth of water and the irregular size of the gravel, the hydraulic elevator or centrifugal pump would not be applicable ; but a modification of the bucket- dredger should prove successful. Large boulders and dead tree-roots, the bugbears of river-mining, are not likely to be en- countered ; whilst fuel suflicient for the necessities of the ma- chinery could be easily obtained — or power could be transmitted electrically from some neighboring waterfall. Great care, how- ever, would be required in prospecting the rivers and studying the conditions of work, in order to have the apparatus thor- oughly fitted to local needs.

Several concessions have already been granted by the State Government to work the river-beds in the auriferous zone ; and it is probable that in the near future a number of dredges will be set to work.

Vm. Land-Tenure.

The lands in the interior of Minas Geraes were originally the property of the Crown, and were distributed to oflicials as gifts or concessions in return for political services. But all minerals were regarded as the exclusive property of the Sov- ereign, and all the deeds contained clauses reserving the min- eral rights. The data or claim, already mentioned, and estab- lished by the Government at the commencement of the in- dustry, served as a unit of title while the work was confined to placer-deposits ; but when lode-mining began, it was decreed that the grants of datas should remain in force only so long as regular work was done on them. During the crisis, at the be- ginning of the last century, when all mining of importance was abandoned, the concessions were allowed to lapse, and only in a few cases renewed. Abuses of all kinds crept in; and, generally speaking, the mining code became a dead letter.

Gold-Field Of The State Of Minas 6Eraes, Brazil. 441

On the proclamation of the Republic, an article of the Con- stitution (copied in great part from that of the United States) declared all land freehold. The freehold tenure of land may be beneficial in many places ; but in a new country like Brazil it has had the effect of creating almost innumerable difficulties in the development of the mining industry, because it placed in the hands of the owners of the freehold (often illiterate men) the power to decide whether mining should be carried on or not Frequently the owners refuse to negotiate at all, or, with extravagant ideas, born in great measure of ignorance and sus-t picion, ask an altogether impossible sum for the mining right or freehold title. Under the old rigime nothing of this kind obtained.

Any prospector, once he possessed the necessary license from the Crown, had the right to explore and mine anywhere provided he indemnified the owner of the surface for any dam-* age done to crops, etc., and paid him the percentage of the net profits prescribed by the Government.

Another source of difficulty is the fact that very often a property is owned in common by a number of heirs or part- ners, who prefer to leave it undivided rather than incur the expense of a judicial division, and who must therefore all join in any grant of permission to mine.

Mining properties may be acquired in the following ways :

1st. By Option of Purchase at a Term and Price Fixed. — This is the arrangement usually adopted by the prospector, who ar- ranges to carry out all the exploratory work while the term of the option is running. To ensure the faithful performance of this contract a penal, clause obliges the vendor to give up his property to the buyer, who, in turn, deposits a sum of money with the vendor, to be forfeited in case of the non-fulfilment of his covenant.

2d. By Simple Leasing of the Land for a Number of Years with Payment of a Fixed Royalty per Ton of Ore Excavated, — Though very common, this method is not recommended, because of the legal difficulty of enforcement. There is a possibility that the owner may sell the property without regard to his contract or lease ; and in that case the lessee can only claim against the proprietor with whom he made the contract, and not against the new proprietor.

442 aOLD-FIBLD OF THB STATE OF MINAS OERAES, BRAZIL.

8d. By the Leasing of the Land for a Short Period with the Op- tion of Purchase. — This is a satisfactory way for a prospector to acquire a property, as it enables him to explore it thoroughly; and his only loss, if the contract is not carried out, is that rep- resented by the amount spent in labor and machinery, the lat- ter of which generally reverts to the owner of the land.

4th. By the Purchase of the Mineral Bights Only. — In Brazil this is not often done ; because separate ownership of the soil and the mineral right is so very likely to cause much friction and bad feeling.

5th. By the Purchase Outright of th£ Freehold. — This practice is most generally followed ; but it is well to note that there is always a possibility of having the title contested, if the negotia- tions are hurried through too quickly. Special care must be taken to see that the boundary-lines are correctly marked, as this has often been a source of contention. In case of a con- test, it is always preferable to avoid litigation and come to some compromise.

At present, the average prospector works at a disadvantage. Very often it is only after making a find that he can enter into negotiations with the owner of the property, who then spreads far and wide the news that mineral has been found on his land, and thus attracts the attention of a capitalist, who may purchase outright, as the prospector cannot afford to do. The capitalist has no knowledge of the property, and no reason for buying it, except the fact that a prospector has found some- thing there indicating mineral value, and a notion that what a prospector desires to get by option or lease is good enough for another man to buy at a venture. In other words, a prospector may be entirely unable to effect an agreement with the land- owner before any discovery ; and after a discovery, the fact that he made it gives him no preference.

It is now suggested that the underground mineral right shall be made to revert to the Government, unless the land- owner shall have registered a mineral discovery, and performed thereon a certain minimum amount of work annually. This would protect the rights of discoverers, operating under Gov- ernment licenses, as is done in Mexico, for instance.

After a property has been acquired, complete freedom from contest may be secured by proceeding at once to have it regis-

Gold-Field Of The State Of Minas Geraes, Brazil. 443

tered under what is known as the " Torrens Register." As soon as these proceedings are satisfectorily concluded, the Gov- ernment takes upon itself the responsibility of defending the title and indemnifying any third parties for loss, if such be proved. The documents required in support of the petition are simple, and consist of plans and description of the property, as well as the titles. The district judge duly publishes the peti- tion, and, if no objection is received within a certain time, he orders the registration to be made. In case protest is made, the suit which follows is specially abbreviated — an important consideration for any company about to begin mining opera- tions.

The Government-tax on contracts is merely nominal, but the tax on transmission of title is generally high — amounting in Minas Geraes to 6 per cent.

It is particularly necessary that prospectors or others operat- ing in Brazil should know the language thoroughly. It is one thing to mine or explore in one's own country, and quite an- other in the interior of Brazil, where language, customs and people are so entirely different.

IX. The Government and the Future of the Mining

Industry.

At the beginning of the last century the gold-tax was 25 per cent., but it was gradually reduced, and finally withdrawn, as the decadence of the industry became general. By reason of the economic crisis caused by the depreciation in value of the staple product of the country — coffee — both the Federal Gov- ernment and the Government of the State of Minas Geraes have begun to give much more attention to the encouragement of mining. All machinery and material for mines may now be im- ported free of duty, and the tax on gold exported has been re- duced from 5 per cent, (at which figure it stood for some years) to 3 per cent. A commission appointed by the Government is now studying the mining laws of various parts of the world, in order to frame a code which will meet the legitimate needs of the industry, and afford assistance to engineers and others visiting the State to examine the conditions of mining, etc.

The ores of Minas Geraes certainly belong to the low-grade -class; but the gold-field possesses many natural advantages.

444 Gold-Field Of The State Of Minas Geraes, Brazil.

Buch as healthy and moderate climate, permitting work at all seasons; facility of transport, abundance of water-power, cheap labor, and good timber, to say nothing of a sympathetic Gov- ernment.

Of failures, this State, like every other gold-field in the world, has had not a few. Most of them, however, can be traced to incompetent technical or business management and the lack of adequate appliances. The rapid rise in Brazilian exchange last year, due to the economic attitude of the present Government, has indirectly caused some loss to the mining companies by increasing the gold-value of mining costs ; but this was only natural, as the price of labor cannot adjust itself immediately to new conditions. In the writer's opinion, when the transition-stage has been passed, the general conditions will be more favorable than before.

The gold-product for tlie last few years is given in Table IL

Table II. — Gold-Product of Minos Geraes.

Year. Oramines.

1896, 1,962,767

1897, 2,071,243

1898, 3,267,080

1899, 3,973,710

1900, 4,811,031

1901, 6,000,000 (approximately.)

It will be seen that the production has more than doubled in 5 years. According to the official returns of the gold taxed up to 1820, and similar data from the modern companies, the total product of Brazilian gold has exceeded £85,000,000 — not a bad record.

The President of the State of Minas Geraes, in his recent message to the Congress, said he was convinced that the mining industry was destined to take the rank formerly held by the coftee-culture, and contribute largely to the financial regenera- tion of the State.

The Chemistry Of Ore-Deposition. 445-

The Chemistry of Ore-Deposition.

BY WALTER P. JENNEY, E.M., PH.D., SALT LAKE CITY, UTAH. (New Haven MeeUng, October, 1002.)

Cx3Ntents.

I. The Beductng Action of Carbon and of Hydrocarbons, Protective Action of Carbon and of Hydrocarbons, III. Contributory Action of Carbonic Acid Gas,

IV. The Stability of Carbonic Acid and of Water, , V. Occurrence of Carbon and the Carbon-Compounds, VL The Occurrence of Carbon, Alone, YII. The Occurrence of Carbon Combined with Hydrogen, Vni. The Belative Beducing Power of Minerals,

I. The RBDUciNa Action of Carbon and of Hydrocarbons*

Carbon has long been recognized as one of the most power* fdl reducing agents in the deposition of ores. Investigations made by myself, of the zinc- and lead-deposits in Southwest Missouri, in the region centering about Joplin,, where the formation of the metallic sulphides has been due to the action of bitumen, carbonaceous shales and bituminous coal, have af- forded abundant evidence that the solid oxygenated hydrocar- bons, particularly when in fine powder and in suspension in the waters circulating through the ore-bodies, are the most energetic and powerful reducing agents known.

Bitumen, liberated by the decomposition of the ore-bearing limestone, is found in the Joplin mines in all degrees of fluid- ity and hardness, dependent on the amount of oxidation it has undergone. From semi-fluid maltha it grades into partly oxi- dized mineral-pitch, which, by further oxidation, changes to hard asphalt, finally breaking up, from continued absorption of oxygen, into a fine powder resembling in appearance powdered coal. In this condition oxidized bitumen, from its light grav- ity, is transported readily in suspension in the underground circulating-waters.

Bituminous coal and black carbonaceous clays and shales occur as surface formations, often in intimate association with

446 Thb Ghbmistby Of Ore-Dbpositiok.

the ore-deposits, and when broken up, crushed, and faulted by <;ru8tal movements, furnish organic matter in a state of fine division. This is borne by the surface-waters and redeposited, often in large masses, in the chaniiels and spaces in the ore- bodies.

Apparently the only pure form of carbon occurring in the ore-deposits of the Joplin region is the charcoal, which is found in inconsiderable quantity in the bituminous coal ; all other -carbon is combined with hydrogen, oxygen and nitrogen.

All these hydrocarbons readily absorb oxygen from the air <3ontained in the subaerial waters, and undergo at ordinary temperatures, even below ground-water level, a slow combus- tion, the ultimate product being carbonic acid and water. They deoxidize the circulating waters by consuming all the free oxy- gen ; and they reduce to sulphides any sulphates that may be in solution. Even ferrous and ferric sulphates, on coming in contact, in solution, with any of the solid hydrocarbons, are at once re-formed as pyrite or marcasite — minerals that reduce all other metallic sulphates, first, by being oxidized to ferrous sulphate, and then, by further absorption of oxygen, to ferric sulphate and limonite.

Bain, writing of these mines, says, " The widespread presence of bitumen has been already emphasized. The ground-water is one great reducing solution."* Nearly every observer in this field has recorded the association of bitumen with the zinc- and lead-ores.

In my paper on " The Lead- and Zinc-Deposits of the Missis- sippi Valley "t I called attention to the reducing action of bitumen and bituminous shales in the formation of the ore- deposits of the Joplin District, and noted the influence of or- ganic matter in the rocks upon the selective deposition of the ores in certain beds in the Cambrian and Silurian of Central and Southeastern Missouri, and also of the Upper Mississippi lead-region.

In limestones containing organic matter, especially if the rock be easily dissolved by waters carrying carbonic acid, the -efficiency of even so minute a quantity as a fraction of one per

The Lead' and Zine-Depotits of the Ozark BegUM, by H. F. Bain, p. 169. t Trafw., xxii., 171-225.

The Chemistry Of Ore-Deposition. 44T

cent, of bituminous substances, in inducing the precipitation and crystallization of the ores, is very great. Small as the proportion of the carbonaceous matter may be, it is liberated by the rapid subterraneous erosion of the lime-strata, in quan- tity more than is required to consume the free oxygen in the ore-forming solutions, and to reduce all sulphates to sulphides* In limestones highly soluble in carbonated waters, two-tenth& of one per cent, of any strongly deoxidizing material, as bitu- minous coal or bitumen, disseminated in the rock, appears to be ample to effect the reduction of the metals, and to induce the deposition of the ores in the special geological formation.

Compared with carbon, hydrogen has far greater reducing power, measured by the amount of oxygen consumed, for hy- drogen, in the production of water, combines with three times the weight of oxygen that unites with carbon in forming car- bonic acid. In fact, hydrogen stands first in reducing power,, accomplishing nearly nine times the work of pyrite, the most efficient metallic sulphide in the redeposition of ores. Sulphur,, oxidizing to sulphuric acid (SO3), requires less than one-fifth the oxygen that combines with an equal weight of hydrogen in forming water.

For illustration, the relative reducing power of hydrogen,, carbon and sulphur may be compared with the heat generated by their combustion, although their calorific values do not run parallel with their respective powers in the deoxidation of min- eral solutions.

A calory being the quantity of heat necessary to raise 1 lb. avoirdupois of water 1° C, the heat generated by the combus- tion of 1 lb. of the following substances is :

Calories.

Hydrogen, 34,462

Carbon, 8,140

BitaminouB coal, 8,750 to 7,800

Lignite 7,300 to 4,600

Sulphur, 2,250

On account of the calorific value of the contained hydrogen,, the heating-power of the highest grade of bituminous coals is greater than that of pure carbon.

It is not improbable that the bituminous coals occurring in association with the ore-deposits of the Southwest, on account of their purity and high percentage of hydrogen, have a some-

448 The Chemistry Op Orb-Dbposition*

what greater reducing power than pure carbon, and are ex- ceeded in power and intensity of action only by bitumen. The lignitic or finely divided coaly matter, disseminated in the black clays and shales, may be regarded for the purpose of this discussion as a form of highly impure bituminous coal. An- thracite may be classed with the bituminous coals, as it con- tains from 1 to 8 per cent of hydrogen and 1 to 8.5 per cent, of oxygen.

The hydrocarbons may be divided into the petroleums, or fluid non-oxygenated compounds of carbon and hydrogen ; the bitumens and asphalts, solid oxidized hydrocarbons, soluble in chloroform or other solvents of the resins ; and the pyro-bitu- mens, which also contain oxygen and nitrogen, including an- thracite, bituminous coal, lignite, etc.

The Oxygenation of Petroleum.

Experiments made by the author on the oxidation of petro- leum show that the heavy hydrocarbon oils unite very slowly with oxygen, when first exposed to its action, even at tempera- tures as high as 150° C. ; but after the action is once started, by the combination of even a little oxygen with the hydrocar- bon, the further oxidation then proceeds with constantly in- creasing energy. By aspirating a current of air for ten days through heavy petroleum oil, at 140° to 155° C, there were formed solid hydrocarbons, resembling certain natural asphalts. Very little water was formed ; the oil " cracking and the hy- drogen being removed in the form of light naphthas and non- condensable gases, containing a greater percentage of hydrogen than the original oil, and leaving oxidized hydrocarbons, with less hydrogen and a greater proportion of carbon.* The asphalts made in the above experiments absorbed oxygen from the air at ordinary temperatures ; the rapidity of the absorption being increased if the asphalt was in a fine powder. Dana refers to these results as the manufacture of grahamite from petroleum, t

The oxides of lead, zinc and manganese, and certain salts of

''On the Formation of Solid Oxidized Hydrocarbons Besembling Natural Asphalts hy the Action of Air on Refined Petroleum,'' by W. P. Jenney, American Chemist, vol. v. (AprU, 1875), pp. 369-362.

t System of Mineraloffy edition of 1898, p. 1020.

Thb Chbmistrt Of Orb-Dbpobition. 449

the metals, notably manganese-borate, are powerful driers of the vegetable oils, such as linseed oil. Even in solution, many salts of the metals have a drying action if agitated with the oil. In the case of the vegetable oils, these metallic oxides and salts appear to exert a catalytic action in accelerating the combina- tion of oxygen with the hydrocarbon.*

Experiments by the writer indicate that oxides of lead and manganese have a similar action in promoting the union of oxygen with petroleum ; and that the asphalts produced retain 2 per cent, or more of lead-oxide, even after treatment with boiling acetic acid and purification by solution in chloroform or ether.t

From this point of view, it is probable that the oxidation of bitumen, in effecting the re-formation of the sulphides, is accel- erated, and the intensity of the reducing action increased, by the catalytic influence of ferrous and ferric sulphates and by the various sulphates, carbonates, chlorides and oxides of lead, zinc, copper and manganese, which are always present in greater or less amount in the ore-deposits. With petroleum having a paraffin base, the union with oxygen would be ex- tremely slow, were not the chemical activity stimulated in some way. Petroleum with an asphalt base, owing to the heavy hy- drocarbons in the oil being combined with oxygen, and ap- proaching fluid bitumen or maltha in composition, would prob- ably absorb oxygen more rapidly.

That the natural asphalts and bitumens, when wet, are more subject to the action of oxygen than when dry, has been ob- served in the wear of asphalt pavements, which rapidly disinte- grate in spots where surface-water accumulates.

The Chemical Reactions that Take Place.

In the reduction of metallic sulphates to sulphides, by car- bon, the action in each case is deoxidation, wiUi formation of carbonic acid, according to the following reactions :

ZnSO, + 2H,0 + 20 ZnS + 2H,C0„

PbSO, + 2H,0 +20= PbS + 2H,00,.

Catalytic action ie nndentood to be the action of a subetance which, bj its presence, accelerates or retards the chemical activity, and may induce a chemical reaction that would otherwise not occur, or would take place only with extreme slowness. t Op, eit., pp. 359-362.

450 The Chemistry Of Ore-Deposition.

The complete reduction of ferrous sulphate to pyrite or to marcasite requires that free sulphuric acid be present :

2PeS0, + 2H,80, + 5H,0 + 7C 2PeS, + 7H,C0,.

The carbonates of lead, zinc and iron, in the presence of alka- line sulphates, are reduced by carbon to the corresponding sul- phides, galena, blende and pyrite :

PbCO, + Na,SO, + 2H,0 + 2C PbS + Na,CO, + 2H,C0,.

ZnCO, + CaSO, + 2H,0 + 2C ZnS + CaCO, + 2H,C0,.

2FeC0, + 4CaS0 + 5H,0 + 7C 2Fe8, +4CaC0, + 5H,C0,.

Chalcopyrite, CuFeS,, is formed by the double reduction ot cupric sulphate and ferrous sulphate :

CuSO, + FeSO, + 4H,0 + 4C CuFeS, + 4H,C0,.

The reactions which take place where the hydrocarbons form the reducing agents are more complex. The hydrocarbons at first lose hydrogen and gain oxygen, until disintegration occurs ; then they rapidly oxidize to carbonic acid and water. With bitumen and coal, it is probable that practically all the carbon is finally converted into carbonic acid, and the hydrogen into water. In the oxidation of petroleum some " cracking " may occur, and a portion of the hydrogen and carbon may escape in the form of light hydrocarbon gases, as did take place in the experiments described above.*

Oxygen seems to be needed to complete the reaction in the reduction by petroleum of the paraffin series :

12ZnS0, + C,,H3, + 0 12ZnS + 16H,C0, + H,0.

Where the petroleum is partly oxidized, ferric sulphate forms pyrite in the presence of an excess of free sulphuric acid. The reaction may be written as follows :

3Fe,(S0,), + 3H,80, + CUJ), 6FeS, + 16H,CO, + 2H,0.

To illustrate the partial reduction of ferric sulphate to pyrite

See p. 448.

The Chemistry Of Ore-Deposition. 461

with formation of ferrous sulphate, the formula of an oxidized hydrocarbon nearly corresponding to humus acid is assumed, as in the following equation :

4Fe,(S0,), + 8H,0 + C„H„0, 4FeS, + 4Fe804 + 16H,C0,.

The complete reduction of ferrous sulphate to pyrite or to marcasite by an oxygenated hydrocarbon, such as gilsonite, Cj, HO, also requires the presence of jfree sulphuric acid :

6FeS0, + C„H,oO + 5H,S0, + 3H,0 6FeS, + ISHCO,

+ 5H,0.

n. Protective Action op Carbon and of Hydrocarbons.

Hydrogen and carbon have affinities for oxygen stronger than those of any other chemical elements, under conditions normally occurring in ore-bodies. By consuming the free oxy- gen in the circulating-waters, they act to preserve and shield from decomposition all metallic sulphides. Otherwise stated, all forms of carbon, and of the fluid and the solid hydrocar- bons, when present in excess, owing to their superior affinity for oxygen, prevent the oxidation of the ores ; although many of the minerals in the ore-bodies under other conditions, where carbon and its compounds are absent, or present only in a sub- ordinate degree, are powerful deoxidizing agents.

In the mines at Joplin, Mo., the metallic sulphide-ores, blende and galena, and the associated minerals, chalcopyrite, pyrite, and even marcasite, are protected from decomposition below ground-water level by the bitumen and the bituminous shale contained in the wall-rock and present in the ore-bodies. Near water-level, on the boundary between the zones of oxida- tion and reduction, these hydrocarbons are consumed in places ; although, a few feet distant in the same ore-body, they may occur in great excess. In such places the metallic sulphides undergo oxidation, only to be re-formed anew on coming in contact with the hydrocarbon.

This protective action has long been understood with respect

to the rocks which contain organic matter. In the black-band

iron-ores, and in many bituminous shales, the iron occurs as the

proto-carbonate (siderite), and is preserved from oxidation by

Vol. .— 28

432 The Chemistry Of Ore-Deposition.

the hydrocarbon. In the outcrop, such rocks are bleached by weathering, and the iron is oxidized to limonite or hematite. That organic matter preserves the strata from oxidation is a fact familiar to persons engaged in collecting fossils, particu- larly fossil-plants. The beds of black and gray shales, where the iron occurs as carbonate or sulphide, are carefully searched, while bright-colored strata, in which the iron is peroxidized, are given only a slight examination.

in. Contributory Action of Carbonic Acid Gas.

In the formation of ore-deposits, carbonic acid gas may, un- der special conditions, displace and expel the air from the cav- ities, channels and interspaces in the rocks, and in this way, by mechanically excluding the air, materially aid the reduction and precipitation of the ores by the ordinary deoxidizing agents. Conditions also occur in the oxidation and re-formation of an ore-body, particularly at those points where the zones of oxi- dation and reduction merge one into the other, under which carbon dioxide would be an efficient auxiliary in the process of reduction.

The specific gravity of carbonic acid gas, compared with air as the standard, is 1.524. Its action in displacing air is not unlike that of water ; a rise in the ground-water from any cause, as is often observed, drives out the air from all the openings in the ore-bodies and checks the oxidation of the minerals.

In the Parker mine. Wood River, Idaho, the country-rock is a lime shale, heavily charged with graphite. Above the per- manent water-level all the seams and joints in the rock are filled with carbonic acid gas, produced by the oxidation of the carbon. Carbon dioxide is found in a zone reaching from ground-water level to within 100 ft. of the surface ; in this zone it fills all the rock-openings as perfectly as water fills similar openings below.*

Sulphuretted hydrogen gas, which has a specific gravity of 1.19, may act in much the same manner in excluding the air, although in itself it is a strong precipitating and reducing agent

See pages 459 and 460.

Thb Chemistry Of Orb-Dbposition, 458

Natural gas, notwithstanding its low specific gravity (0.668), may be held under pressure in the strata in much the same way as it occurs sealed in the interspaces of the Trenton lime- stone of the Ohio and Indiana gas-field.

At the Silver-Islet mine, Lake Superior, pockets filled with hydrocarbon gas were struck in drifting on the vein on the 8th (440 ft. vertical depth) and 10th levels (610 ft. depth). The gas was held confined in the seams of the slate and in the openings in the vein under a water-pressure of from 440 to 600 ft, equal to a pressure of from 190 to 266 lbs. per square inch.*

Observations at many gas-wells show that the pressure greatly exceeds that which would be due to a water-column equal in height to the depth of the gas-producing strata. There is no record of any measurement of the gas-pressure at Silver-Islet

IV. The Stability of Carbonic Acid and of Water.

Carbonic acid when combined with a base is a weak acid, readily displaced by a stronger, as sulphuric, hydrochloric or phosphoric acid, and also by sulphur and by many of the organic acids. But the molecule of carbonic acid is never broken up, is never separated into its component elements under conditions ordinarily subsisting in the earths crust, at least not at the depths reached in the underground circulation of meteoric water.

Volcanic action alone, or an earth-temperature far above normal, furnishes the physical conditions in which carbon dioxide is dissociated, or the conditions that admit of its being reduced to the monoxide by carbon, or by other deoxidizing agents.

Carbonic acid is a permanent refuge of oxygen ; once locked up in combination with carbon, oxygen remains inert for all time, in a condition of stable equilibrium, inactive, and chemi- cally indifferent to all the complex changes taking place in the depths of the earth.f Even in ore-deposits undergoing oxida-

''The Silver-Islet Mine and Its Present Development," by Francis A. Lowe, Enff. and Min. Jour,, vol. xxxiv., pp. 320-323. See, also, p. 486, this paper, "Sil- ver-Islet Mine, Lake Superior" (author unknown, with Supplement No. 1, by W. M. Courtis), Eng. and Min, Jour,, vol. xxvL, p. 438.

f Carbonic acid gas contains : Carbon, 27.27 per cent ; oxygen, 72.73 per cent.

454 The Chemistry Of Orb-Deposition.

tion and re-formation, carbonic acid, once formed, is itself in- susceptible to chemical change. Neither hydrogen, carbon, sulphur, or the most powerful deoxidizing metallic sulphides, can decompose it at ordinary temperatures. This immutability, however, is maintained only under the conditions subsisting in the depths of the strata, where life does not exist ; the carbonic acid in the soil and in the atmosphere readily gives up its oxy- gen and carbon to plant-life.

Water almost equals carbonic acid in stability. It is true that water is decomposed by electrolysis and in many chemical reactions in the laboratory ; yet, at temperatures approaching the normal, water is probably not dissociated, except in a very limited way, in any of the processes incidental to ore-for- mation.

In the complex chemical changes that take place in the oxi- dation and re-formation of ores, it is possible that water may be decomposed; but, quantitatively, such dissociation must be insignificant. Practically, water may be regarded as chemi- cally stable under ordinary conditions and temperatures. The fact that, in the presence of the deep-circulating underground waters that contain no free oxygen, the complex sulphides forming the ore-bodies have been preserved unaltered for ages, is evidence that water is chemically inert to all the elements present in the depths of the strata.

Among minerals, many oxygen compounds, as, for example, quartz, corundum, cassiterite, rutile and zircon, resist decompo- sition, as do also the silica, the alumina and the other acid rad- icals in silicates, aluminates, borates, phosphates, titanates, tan- talates, tungstates and chromates. Minerals containing oxides of the alkalies and the alkaline earths, while usually perma- nent, may have their oxygen displaced by sulphur and by the halogens, chlorine, bromine, iodine and fluorine. In the greater number of the refractory minerals and permanent oxygen-compounds, the chemical union of the elements with oxygen may probably date back to the primal origin of the earth.

Carbon and hydrogen alone, of all the elements, unite with oxygen under conditions now subsisting in ore-deposits, to form fixed compounds, that, sealed in the rocks, can endure to the end of time.

The Chemistry Of Orb-Deposition. 455

V, Occurrence op Carbon and the Carbon-Compounds.

Carbon occurs as graphite in the metamorphic rocks and in the gangue of certain mineral-veins. It is also found, practi- cally free from hydrogen, as graphitic anthracite, and, in small quantities, as native charcoal. In all cases carbon is the re- sidual element in the decomposition of the organic matter de- posited in the original sediments; the hydrogen, oxygen, nitro- gen and sulphur with which it may have been combined have been eliminated.

Far more commonly, carbon, when in association with min- eral-deposits, is combined with hydrogen and oxygen, usually in the form of bituminous coal or bitumen in the wall-rocks, or filling the ore-bearing fissures ; in some instances, as in the Joplin, Mo., mines, it is distributed generally throughout the ore-bodies. In most carbonaceous shales, in the mining re- gions, the organic matter is mainly in the form of finely dis- seminated bituminous coal.*

It is somewhat remarkable, considering the almost universal distribution of petroleum, that the non-oxygenated hydrocarbon oils are found so seldom, either in the ore-deposits or in the ore-bearing formations. In a few instances, marsh-gas and other similar hydrocarbons which are gases at ordinary tem- peratures and pressures have been found in association with mineral-deposits.

VI. The Occurrence of Carbon, Alone.

Graphite,

In the metamorphic area of the Black Hills of South Dakota many large, irregular deposits of pyrrhotite occur, associated with belts of graphitic shales. Masses of crystalline pyrrhotite are encased in soft, black, shaly gangue-rock, carrying a large percentage of graphite. As observed by the author, these graphitic shales appear to form a specially favorable gangue for pyrrhotite, associated with ores of nickel and copper, and also for pyrite and arsenopyrite.

An analysis of the Hudson-Biver slates (Lower Silurian) gave 5 per cent, of fixed carbon and 3 per cent, of volatile oombostible matter, or nearly in the pro- portion of carbon, 62.5 per cent ; volatilCi 37.5 per cent. ; corresponding to the composition of the best gas-coals. "Classification of Goals," by Persifor Frazer, Jr., TraiM, vi, 448.

456 The Chemistry Of Orb-Deposition.

Pyrrhotite is mined in the vicinity of Deadwood, S. D., for flux in pyritic smelting* The mineral shows on assay an aver- age value of $1.00 to $2.00 per ton in gold, with usually less than 0.25 per cent, of copper. Many of the deposits of pyrrho- tite in the region lying easterly and northeasterly from Har- ney's Peak carry a small percentage of nickel and copper. Dr. Carpenter says that assays of the nickeliferous pyrrhotite from this region, made at the Dakota School of Mines, show an average of 1.5 per cent, nickel, though samples carrying 8 per cent have been found.*

F. M. F. Cazin describes the occurrence, in the Vermont copper-mine, of deposits of the sulphides of iron and copper in intimate association with graphite.f

Prof. F. Kemp notes that graphite, or some closely re- lated carbon mineral, is not uncommon in the ore of the Mary mine, at Ducktown, Tenn. He says, " It must have been in- troduced as some gaseous or very mobile liquid hydrocarbon, which has penetrated into minute cavities and filled larger cracks, and has been subsequently changed to graphite."J

Von Cotta, in his " Treatise on Ore-Deposits," cites many in- stances of the influence of carbon on the localization of ore-de- posits. A single quotation is selected: "Near Freiberg the veins . . . are enclosed in mica schist which contains an irregu- lar layer of black graphitic schist. . . . The veins have only been found productive in the black schist. In the common mica schist they are very poor."§

iver Islet. — In the Silver-Islet mine. Lake Superior, graphite was found associated with native silver, silver-glance, tetrahe- drite, argentiferous galena and a number of rare silver miner- als, in a gangue of quartz, calcite and rhodochrosite. The geo- logical formation is gray slate, nearly horizontal in bedding, traversed by steeply dipping, parallel dikes of diorite and other igneous rocks. The vein cuts vertically across the dikes and

" Ore-Deposits of the Black Hills of Dakota," by Franklin R Carpenter, Traru,, xvii., 582.

t Genesis of Ore-DeposiUy pp. 207-209; Trans, , zxiii., 605,606. See, also, on this subject, "The Origin of the Gk>ld- Bearing Quartz of the Bendigo Reefs, Aus- tralia/' bj T. A. Bickard, TVam., xzii., 314, 315.

X "The Deposits of Copper-Ores at Ducktown, Tenn,'' by J. F. Kemp, Tram,, xzzi., 261.

i Treatise on Ore-DeposUsy Prime's Translation, pp. 46, 47.

The Chemistry Of Ore-Deposition. 457

the belts of slate included between them, but was ore-bearing only where it faulted the main dike of diorite. This dike, about 200 ft. in width, was in certain places strongly impreg- nated with graphite.* Intersecting fissures appear also to have had an influence on the localization of the ore. Two bonanzas were discovered : (1) The main ore-shoot (that produced over $2,000,000) extending from the surface to a depth of 330 a, nearly to the 7th level, and formed at the intersection of a cross-vein with the main lode ; (2) the rich body of native sil- ver on the 3d and 4th levels, south (that yielded 800,000 oz. of silver), occurring near the junction of the two branches of the vein. Graphite was not found in the slates, or in any dike of the igneous belt intersected by the vein-fissure, with the excep- tion of this particular dike, which in its limited outcrop above the surface of the lake, at the point where the lode cut through it, formed Silver Islet. The vein in no place carried workable ore-deposits, either in the slates or in the normal diorite. Be- fore the mine wa closed down, a small body of ore (that pro- duced about $30,000) was struck on the 13th level, south. Like the larger ore-bodies in the upper-levels, the ore was found to occur in association with graphite. McDermott, writ- ing of this mine, says : " The fact most striking, to one who ex- amines the parts of the vein from which the most valuable ore has been extracted, is the evident connection of the deposit of the silver with the region of graphite impregnation of the wall-

rock."t

Graphitic Anthracite.

An extensive deposit of graphitic anthracite, associated with antimonial silver-lead ores, was found in the Parker mine, in

''The trap-dike has usaaUy been called diorite, but is determined to be norite by Wadsworth, BvU. No. 2, Minn, OeoL Sur.j p. 92, and gabbro by Irving, Mono- graph v., U, & OeoL Sur., pp. 378, 379." Ore-Deposits of the U. S. and Oanada, by J. F. Kemp, p. 283.

t Silver-Islet Vein, Lake Superior," by Walter McDermott, Eng, and Min. Jour. J vol. xxiii., pp. 54, 55 and 70, 71.

"The Silver-Islet Mine and Its Present Development," by Francis A. Lowe, Eng. and Min, Jour,, vol. xxxiv., pp. 320-823.

''Silver Islet," by Thomas Macfarlane, Trans,, viii., 226-253.

"The North Shore of Lake Superior as a Mineral-Bearing District," by W. M. Courtis, Tram,, v., 473-487.

"Silver-Islet Mine, Lake Superior" (author unknown, with longitudinal sec- tion of the mine. Supplement No. 1, by W. M. Courtis), Eng. and Min, Jour,j vol. xxvi., p. 438.

458 The Chemistry Of Ore-Deposition.

Idaho. The vein occurred in a belt of graphitic lime-ehales, about 600 ft. in width, included between two intrusive sheets of andesite ; the whole formation — the vein and the igneous sheets bounding the shales above and below — dipping into the moun- tain at an angle of 40 degrees. The ores were galena and polybasite, averaging (in car-lots) from 75 per cent, of lead and 125 ounces of silver to 45 per cent, of lead and 680 ounces of silver per ton. The gangue was an intimate mixture of white crystalline calcite and quartz. An intersecting vein, coming in from the foot-wall, carried crystallized pyrite and blende, with only traces of silver. The mine produced $365,000. At a vertical depth of 800 ft. from the surface a flat fissure was en- countered, filled with graphitic anthracite with a little white quartz intermixed. It formed a flat sheet, 2 to 6 ft. in thick- ness, and was explored over an area 200 ft. square. The coal was heavily slickensided, crushed and compacted into a hard, granular mass. It was mined with difficulty with a pick, and often required blasting, owing to the stringers of quartz dis- tributed through it. Analysis gave, excluding ash, 90 per cent, of fixed carbon and 10 per cent, of volatile matter, mostly water from the clay contained in the ash. Owing to admixture of quartz and earthy material from the walls, the ash varied from 10 per cent, to 50 per cent. This coal had evidently been formed by the destructive distillation of asphalt or petro- leum, filling the fissure. The intrusion of the sheets of vol- canic rock enclosed the shale stratum as if in a retort. There is evidence, in the large amount of graphite in these shales, that they were originally highly charged with bituminous matter. The hydrocarbons, first distilled by the heat accom- panying the intrusion, were condensed and accumulated in the fissure as heavy petroleum or asphalt, and, by further action of heat, carbon was deposited, hydrocarbon oils being driven off in the same way as in the distillation of petroleum-tar in the manufacture of lubricating oils. Subsequently the deposit was crushed by faulting movements of the beds, and at a still later date the ore-deposits were formed in the intersecting vein-fissure. In places the ore lies against and extends into the coal. Natu- ral gas was not encountered, though conditions were favorable for its formation, probably because the workings were near the surface. Heavy flows of carbonic acid gas were, however, fre-

Thb Chbmistrt Of 0Re-Dbp08Iti0N. 459

quently encountered in the mine ; and during occasional periods of low atmospheric pressure the outflow of gas from the seams and fissures in the country-rock was so much increased that the miners were often driven from parts of the mine that were not well ventilated.*

J. B. Farish notes that the seams in the limestones at New- man Hill, near Rico, Col., were filled with carhonic acid gas.f

Charcoal.

Native charcoal, or mineral-charcoal, as it is termed, is prob- ably never pure carbon, yet the amount of hydrogen contained is so small that in the discussion of its reducing power it may be classed with graphite. Observation shows that charcoal, from its soft, porous structure, and from the great surface it exposes to chemical action, is one of the most energetic deoxi- dizing agents in the formation of ore-deposits.

Small pockets filled with charcoal were found at a depth of 800 ft. in the ore-chimney of the Bassick mine, near Silver Cliff, Colorado. This remarkable occurrence of charcoal in an eruptive formation is set forth in detail in the paper by L. R. Grabill-t

In the discussion of this paper, the occurrence of charcoal in anthracite was described by C. A. Ashburner ; and of char- coal in Oregon, formed by the carbonization of the leaves and twigs of plants in the layers of mud between successive over- flows of lava, by Dr. R. W. Raymond. §

President Rothwell remarked : " Charcoal has also been found in the silver-bearing sandstones of Southern Utah. These sandstones are a simple sedimentary formation, and contain trunks of trees, some finely silicified, ... I have also found there pieces of lignite, with the structure of the wood still quite evident. . . . Other portions of the carbonaceous matter have almost the character of charcoal; the carbon has not become hard, nor taken on the form of lignite. The woody

♦ "Graphitic Anthracite in the Parker Mine. Wood River, Idaho," by W. P. Jenney, School, of Mines Quarterly (1888-89), vol. x., pp. 313-316.

t *'0n the Ore-Deposits of Newman Hill, near Rico, Colorado," Proceedings of the Colorado Scientific Soeietyf vol. iv., p. 153.

t ''On the Peculiar Features of the Bassick Mine," by L.R. Grabill, Trans.y xi., 110-120.

I Ibid., p. 119.

460 The Chemistry Op Ore-Depositiok.

fiber of ordinary charcoal can be traced in it very clearly. . . In the silver-bearing portions of the beds, the charcoal, the lignite, or the silicified wood, as the case may be, is impreg- nated with chlorides or sulphides of silver, and is in many cases quite rich."*

The deposits of silver-ore in sandstone at Silver Reef, Utah, are mainly due to the reducing action of wood and plant remains, more or less perfectly altered to lignite, and are treated in more detail under that head.f

VII. The Occurrence of Carbon Combined with Hydrogen.

Bituminous Coal.

Blende and galena have been deposited in coal in the outly- ing basins of the Coal Measures, scattered along the broad, northern marginal belt of the Ozark Uplift.

Near the reservoir at Sedalia, Mo., a basin in the Second Magnesian Limestone carries a little coal of fair quality, in which dark brown crystalline blende occurs in small irregular bunches and in sheets filling both the vertical and horizontal seams and joints. The greater part of the blende is in sheets, J to IJ in. thick, made up of agglomerated imperfect crystals, compressed or flattened between the layers of the coal. Some specimens show blende in thin parallel seams, not thicker than a sheet of paper and to in. apart, distributed regu- larly through the coal. About 2 tons of blende were mined at this locality.

In Morgan and Moniteau counties. Mo., in a number of places, blende and galena are found in similar deposits of coal. At Martin's coal-bank, near Versailles, Mo., the coal has evi- dently been disturbed since its deposition, and vertical seams in the coal, J in. to 1 in. in , are filled with sheets of crystal- line blende and galena in a gangue of calcite and white tallow- clay. The strike of the lines of disturbance of the coal, pro- longed 500 to 1000 feet southerly, crosses an extensive tract of old surface-workings in the Second Magnesian Limestone. The ground is thickly covered by shallow pits, dug in search of lead-ore. These deposits of lead were apparently formed

Ihid,, pp. 117, lis. t See pp. 462-467.

The Chemistry Of Orb-Deposition. 461

through the agency of the same system of fissures that intro- duced the ore in the coal.

Blende and galena were formerly mined at Simpson's coal- bank, in Moniteau county. The coal is a hard cannel, filling a basin in the Second Magnesian Limestone ; the ores occur in seams, seldom more than an inch in thickness, in the joints of the coal. The ore incidentally obtained in mining the coal afforded an occasional shipment to the smelters.

Vanadium is found in a lignite coal in the province of Men- doza, Argentine Republic. The ashes of this coal carry van- adic acid, . It also occurs in anthracite mined near Yauli, Peru.*

Gold has been repeatedly reported in the ash of the Creta- ceous coals of the West. H. M. Chance records that the coal of the Cambria Coal Co. near Newcastle, Wyoming, is said, by the chemist of the company, to carry gold.t Mr. H. Rive& Ellis, of Salt Lake City, informs the writer that he obtained an average of 60 to 80 cents gold per ton of ash from the Pleasant Valley, Utah, and Kemmerer, Wyoming, coals. In this con- nection, the paper by G. A. Koenig and M. StockderJ is of interest, although the coal described appears to be more nearly an infusible hydrocarbon, such as might result from the par- tial oxygenation of albertite.

Mr. Henry Sewell describes the occurrence of antimonial silver-ores, in association with strata, carrying beds of bitu- minous coal, in the mineral caves of Huallanca, Peru, located at an elevation of 14,700 ft. above the sea. These silver-mines are situated in a coal-formation, upturned on edge by an out burst of porphyry, the upheaval forming immense backbones, with the stratification standing almost perpendicular. A bed of coal is mined for blacksmithing purposes within a distance of 150 yards of the ore-bearing beds. The ore is tetrahedrite, with about 800 ounces of silver per ton, and occurs lining cav-

21e Annual Bepart of U, S. Oeol, Sur,, 1899-1900, Part VI.; Mineral Re- smtrees of the U. S,, p. 315.

t Discovery of New Gold Districts," by H. M. Chance, Trans, , xxix.

t the Occurrence of Lustrous Coal with Native Silver in a Vein in Por- phyry, in Ouray County, Colo.,'' Trans,, ix., 650. See, also, "Modes of Oc- currence of Pyrite in Bituminous Coal," by Amos T. Brown, 2Vaw., xvi.

462 Thb Chemistry Of Orb-Dbposition.

ems, in beds of sandstone. 8ome of these caverns are 25 to 30 ft. long and of nearly equal height, their inner surfaces covered with a coating 2 to 8 in. thick of crystallized silver-ores, mostly tetrahedrite. Silver-ores also occur in the shale beds adjacent to the sandstone.*

Lignite.

At Silver Reef, Utah, silver has been deposited in lignitic- sandstones, determined by Newberry to be of Triassic age.f The mines since 1885 have only been worked by leasers in a small way. During the height of production in 1877-79, the total output was 2,122,471 ounces of silver.J The ore-bearing beds were 30 to 40 ft. in thickness, of which usually only 16 ft. was pay-ore. The ore occurred in flat shoots that were, in some places, 300 ft. wide, and extended 400 to 500 ft. deep on the dip of the formation. The ore was richest near the out- crop, and, as it was followed in depth, gradually got poor. Near the surface the silver was in the form of chloride, associated in places with the blue and green carbonates of copper in very small quantity. As the ore was followed in depth, the chloride gave place to silver-sulphide, and scales of native silver came in, especially in the branches of trees and distributed in the plant-shales. No other ores were found, and the gangue-min- erals usually occurring in ore-deposits, as quartz, calcite, barite, etc., were absent. When, following the inclination of the strata, the workings attained a vertical depth of 400 to 500 ft., the ore changed, becoming low-grade and difficult to amal- gamate in pans; the ore-shoots at the same time contracted, becoming narrow, and only 2 or 3 ft. in height. Exploration was continued for several years, but finally all search in depth for pay-ore was abandoned. §

"The Silver Caves of Peru,'* by Henry Sewell, Eng, and Min. Jour. vol. XX i v., p. 292. Abstract taken from the London Mining Journal.

t "Report on the Properties of the Stormont Silver-Mining Company at Silver Reef, Utsih,** by J. S. Newberry, Eng, and Min, Jour., vol. xxx., p. 269. See, also, "The Silver Reef Sandstones," by J. S. Newberry, Eng, and Min. Jour., vol. xxzL, p. 4.

t Eng. and Min. Jour., vol. xxix., p. 26.

i "Silver Reef District, Southern Utah" (author unknown), Eng. and Min. Jour., vol. xxix., pp. 25-26, 46-46, 69-60, 79-80, and 96.

"The Silver Sandstone District of Utah," bv C. M. Rolker, Trans., ix., 21.

" The Peculiar Features of the Bassick Mine ;" Discussion by R. P. Rothwell, Trans., xi., 117-119. Oenegis of Ore-Depogits, pp. 130, 131.

The Chemistry Of Ore-Deposition. 46&

Many writers report that traces of silver and copper occur in the extension of these same sandstone reefs, which can be traced by their outcrop for a distance of 10 to 20 miles to the southwest. An unknown autlor, in the early development of the district (May, 1877), thus describes the peculiar occurrence of the ore : " The formation is a beautifully stratified red and white sandstone, but greatly broken up and eroded. Where the strata have been undisturbed they rise to a height of per- haps a thousand feet above the adjacent valley, in table-moun- tains, alternately banded in red and white, and plainly showing the former height of the whole country. The numerous ex- tinct volcanoes and the vast quantities of volcanic rock found throughout southern Utah, and particularly this section, point to at least one agent, and, no doubt, a powerful one, which served to produce the numerous foldings and contortions of the strata, while the great sandy deserts, covered with sage and cactus, bear abundant evidence to the erosion. On the north- ern side of what was once a vast basin, lying between several ranges of high mountains of old rock, where the erosion of an anticlinal has left ridges of reefs cropping out at various an- gles, are situated the mines. . . . The sandstone consists of red and white deposits, carrying some lime as a cementing ma- terial, with occasional layers of clayey or shaly rock, and con- siderable carbon scattered throughout. This carbon, which is evidently from the decomposition of drift material, of which the impression in the rock and even the plant itself is yet dis- tinct, occurs in important layers in places. . . . Petrifactions, even of the size of large trees, are not uncommon, some of which form a valuable ore. The white sandstone, which ap- pears to be of a somewhat finer texture than the red, seems so far, to have carried the ore. . . . These veins, as they are there called, are entirely conformable with the strata, and in no case do they cut across the adjacent layers of rock. They appear to be richest where there is the most carbon, which evidently has acted as a reagent to precipitate the silver from solution and to deposit it, sometimes as flakes of metallic silver, in its midst. In some cases the form of the plant, of apparently a reedy nature, is yet distinct, in which the cells are yet visible, but to a great extent filled with valuable ore. Other beds carry considerable copper in the form of blue or green

464 The Chemistey Of Ore-Deposition,

carbonate, and also iron in nodules which run very high in sil- ver. ... A light sandstone, containing streaks or fine layers of a dark material, which elsewhere would not attract atten- tion, is there found, sometimes, run from $50 to $100 a ton ; while the darker rock, containing considerable carbon, copper, or iron-nodules, will at times run into the hundreds, or even thousands."*

Mr. Watson M. Nesbit, who was connected with mining oper- ations at Silver Reef from 1878 to 1888, gives the author the fol- lowing statement of the manner of occurrence of the ore: In the Barbee and Walker mine, water was struck at a depth of about 500 ft. vertically. Near that point the ore changed in appear- ance and character, and gave great trouble in amalgamation, the extraction being very low. The ore was treated hot, in pans ; a thick scum rose on the pans, like heavy petroleum oil, and had to be removed from time to time during the amalgama- tion. From a charge of tons of ore, as much as a gallon of this oily material would be obtained. The ore at water-level, if carefully stoped, averaged 12 to 16 oz. of silver per ton ; but only a part of the silver could be saved in pans. A very little pyrit appeared at water-level — the first seen in the mines. About 100 to 200 ft. above water-level, on the slope of the beds, the ore was in places very rich ; and small bunches of lignite coal, 4 to 10 in. across, were found imbedded in the soft sand- stone, with native silver deposited in thin scales on the joints of the coal. Most of the ore at this depth was silver-sulphide* At one place a tree-trunk, 18 in. in diameter, was found ; the heart-wood was silicified and very hard, and carried 8 to 10 oz. of silver per ton. The sap-wood and bark, 8 to 6 in. in thick- ness, were altered to soft, crumbling lignite, ftiU of silver-sul- phide ; it assayed 6000 oz. of silver per ton. The ores from the Silver Reef mines never showed any gold by assay ; but in leaching the ore by the Russell process, the silver-sulphides produced contained a trace of gold.

Review of the Phenomena at Silver Reef. — Light is thrown on the change in the mineral character of the ore at water-level, and on the difficulty experienced in amalgamation, by the dis-

The Silver Sandetoneg of Utah," by C. F. A., Salt Lake City, Bag. atid Min. Jour.f vol. zxiii., p. 317.

The Chemistry Of Ore-Deposition. 465

cover announced by Newberry* that the ores carried selenium, — the average of four analyses giving selenium, 0.28 per cent., and silver, 0.26 per cent. The selenium in one specimen amounted to 90 ounces per ton.

Whether the silver was deposited at the same time the sedi- ments were laid down, or was introduced by solutions upflow- ing through faulting-fissures in a later geological age, has been a much debated question. Without dwelling upon this point, — for, in either event, the primary deposition of the ore was due to the hydrogen and carbon of the plantremains enclosed in the sandstones, — certain peculiar features of the occurrence deserve notice. The structure at Silver Reef may be stated as a broad anticlinal arch, broken up by faults coursing northerly and southerly, rudely parallel to the axis of the fold. A basin, nearly 8 miles across, occupied by the valley of the Virgin river, was eroded through the crest of the arch, leaving the two clifls . facing one another, the strata dipping away from the basin on the two sides. The total area of the several ore-producing belts of sandstone-outcrop, left by erosion, covered less than 500 acres.

Silver Reef conforms to the general law of areal distribution of mining-districts, namely, that " Ore-deposits have been formed ordy in local areas of disturbance. Between and surrounding such areas of mineralization extend broady barren tracts of undisturbed strata "1i and also conforms to the law of mineral occurrence, namely, that " All workable deposits of ore occur in direct associa- tion faulting-fissures traversing the strata and with zones or beds of crushed and brecciated rocks produced by movements of disturbance. The undisturbed rocks are everywhere barren of oreJX The de- scriptions apply to a mineral area which, prior to the recent erosion of the basin, may have possibly covered four or five square miles, with pay-ore found in no place outside this special area.

A writer notes that only the fractured, jointed and perme- able portions of the bed are rich ; where undisturbed and massive, the sandstone is barren. Also that vertical fault-

♦ "The SUver Reef Sandstones," by J. 8. Newberry, Eng, and Min, Jour., vol. zxxi., p. 5.

t "Lead- and Zinc-Deposits of the Mississippi Valley,'* by W. P. Jenney,

466 The Chemistry Of Orb-Deposition.

planes frequently bound the ore.* These are conditions that are found in impregnated beds of zinc- and lead-ores in Southwest Missouri and Northern Arkansas, and also in the flat deposits of gold, associated with tellurium, in the Cambrian sandstone near Deadwood, South Dakota.

Selenium usually occurs with minerals believed to have been formed by highly-heated vapors and solutions and in direct association with igneous disturbances. Its presence at Silver Reef seems to favor the theory of the deposition of the silver through the fissures. It appears that secondary enrichment has taken place on an extensive scale, and that the silver was deposited originally in the sandstone in combination with sele- nium and probably with sulphur by the reducing action of the lignitic matter. Afterwards, these primary ore-bodies were en- riched by the secondary precipitation of silver-sulphides, by the agency of descending surface-waters, aided greatly by the pro- gressive erosion of the basin. In this migration of the ore — the outcrop of the sandstone gradually disintegrating and wear- ing away from exposure to weather — to the deposits of silver- sulphides, re-formed at deeper levels on the dip of the same beds, the reducing agent has been the organic material distrib- uted through the ore-horizon. Later, these reinforced ore& were, near the outcrop, altered to silver-chloride, cerargyrite, the trace of copper occurring with the silver forming the car- bonates, azurite and malachite. When the mine-workings passed below this zone of enrichment there were found only small bodies of ore, that had remained unaltered since the first deposition of silver in the beds.

Similar occurrences have been described of copper-ores re- placing the wood of trunks and branches of trees, and encrust- ing the leaves and stems of fossil-plants, in the Triassic sand- stones of New Mexico,t and in the Permian sandstones of Russia.

E. J. Schmitz writes of the occurrence of copper-ores as

**Silver Reef District, Southern Utah," by B. P. RothweU or Thom Couch (?), Eng, andMin, Jour., vol. xxix., pp. 25-26.

t " The Origin of Ck)ppep- and Silver-Ores in Triassic Sand-Rock," by F. M. F. Cazin, Etig, and Min. Jour., vol. xxz., p. 381. ''The Silver Beef Sandstones" by J. S. Newberry, Eng, and Min, Jour., vol. xxxi., pp. 4-5.

t Transit ix., p. 33.

The Chbmistrt Of Ore-Dbposition. 467

pseadomorphic replacement of wood and branches of trees in bitaminous clay-slate in the Permian of Texas.* In the dis- cussion of this paper, Mr. Henry Louis describes deposits somewhat analogous in the Permian of Nova Scotia, at New Annan, where the ore occurs in nodules of chalcopyrite, chalco- cite, and iron-pyrites,t associated with plant-remains converted into anthracite.

Posepny also describes remarkable specimens of tree-trunks altered to galena from the Vesuvius mine, Freihung, Bavaria.

Bituminous Shales.

Rich deposits of blende, formed in great part by the second- ary enrichment of smaller, or lesB mineralized, primary ore- bodies, are found near the surface in the Joplin, Mo., district, in the vicinity of Carthage, Lehigh, Central City and Reding's Mill. At these localities the ore occurs in two ways : in the beds of soft, decomposed carbonaceous shales in the Coal Meas- ures, occupying shallow basins in the Subcarboniferous lime- stone of the region ; or, more commonly, in horizontal chan- nels eroded in the underlying limestone and filled with soft, dark mud, intermixed with bituminous matter, derived from these same shales, crushed by faulting movements and washed into the openings by surface-waters. Without regard to the character of the enclosing formation, these forms of ore-deposit are known to the miners as " mud-runs." These occurrences are seldom far from the surface ; the deepest " run " of this character observed, near Reding's Mill, was at a depth of 90 ft. At Lehigh, similar deposits were found in the bottom-lands along the stream, within a few feet of the surface, where the permanent water-level came near to the top of the ground.

The ore occurs in minute crystals, thickly disseminated through the soft, shaly gangue, or enveloped in semi-fluid black mud. In some of the deposits the crystals of blende are agglomerated, forming irregular masses and sheets of pure ore. The crystals are of uniform size, usually from to of an in.

♦ "CoppeiOres in the Permian of Texas,*' by E. J. Schmitz, Trans,, xxvL,

t "Copper-Ores in the Permian of Texas ;'' Discussion by Henry Louis, Trans. xxTi., 1061, 1052.

X Oenesis of Ore-DepwiU, pp. 129, 130. VOL. XXXIII.— 29

468 The Chemistry Of 0Rk-Dbp08Iti0N.

in diameter, transparent, resin-yellow in color, with a shade of red, resembling in appearance the small garnets found in some placer gold-bearing gravels. The small size of the crystals is probably due to the concentration of the solutions from which they were deposited, and to their rapid formation. In some instances blende forms crystals in these shaly beds from in. to more than an inch in diameter, presumably from a slower and more prolonged growth. In all the deposits of this type, the reducing agent has been bituminous matter acting upon surface-waters, which carried in solution the sulphates of the metals leached from ore-bodies at higher levels, that were un- dergoing oxidation. The following equation shows the char- acter of the change :

ZnSO* + 2CH + H,0 + 0 ZnS + 2H,C0,.

It has been observed that these shallow mud-runs usually occupy synclinal basins or troughs, and that surface-erosion has ojften removed a considerable depth of the ore-bearing forma- tions from the immediate vicinity; the deposits being located where they have received the drainage from surrounding min- eral-areas.

At the Britton mine. Central City, the ore occurs at a depth 40 to 50 ft. from the surface, in a broad, flat, compound-run, 75 to 150 ft. wide and 6 to 12 ft. high, developed on its course for a length of 560 ft., northerly and southerly.* The ore is granular, crystallized blende in a stratum of soft, black mud and broken chert. The particles of blende are less than in. in diameter, deep garnet-red in color, and, although thickly distributed in the mud, are not agglomerated. A number of similar deposits are developed in the vicinity.

Ore-deposits of this character are easily mined with pick and shovel ; powder is only used to break up an occasional boulder in the ore-body. The ore requires very little crushing and readily concentrates, yielding from 12 to 20 per cent, of clean blende. The product is very pure, assaying from 62 to 64 per cent, of metallic zinc.

Reding's mine, about 4 miles southeast of Joplin, is situated

For a definition of these forms of ore-deposits, see Lead- and Zinc* Deposits of the Mississippi Valley/' by W. P. Jenney, Trans. xzii., 189, 190.

The Chemistry Of Orb-Deposition. 469

in a shallow basin in a low range of hills, bordering the north side of the valley of Shoal creek. At the time of the exami- nation, this mnd-run was opened 75 ft. in length, north and south, with a width of 86 ft., and a height of 12 to 18 ft. The ore occurs in dark-brown mud, in finely disseminated crystals, and in crystallized masses and sheets of galena and blende. Beautiful specimens of galena are found in very perfect cubical crystals, 1 to 2 in. on a side. The upper part of the run is mostly crystallized galena, while the lower part is blende, with a smaller proportion of galena. Boulders of flint and black clay-shales are found in the ore, together with much coarsely crystalline rotten dolomite.

This ore-deposit is remarkable for its extreme richness. To the date of my examination, the yield of the mine, estimated upon all material extracted, had been 15 to 20 per cent of clean ore. When first formed, it was evidently a small run of blende and galena in dolomite ; subsequently, surface-waters eroded a cavern-like channel following the course of the run. Material washed from the surface formations of broken and crushed bituminous shale filled this channel and enveloped the ore-body. Finally, the ore primarily deposited was greatly reinforced by secondary position, both galena and blende being crystallized in the fluid mud by the reducing action of the hydrocarbon.

A small basin of coal-shales, near Belleville, Jasper county, Mo., carried beautifully preserved fossil-plants. The outer surface of the mass of shales, for a depth of about a foot, con- tained scattered crystals of blende, from J to f in. in diameter, mingled with a few crystals of galena and pyrite. The central portion did not carry any mineral, the mass having been min- eralized from the outside, toward the interior, as far only as the mineral-bearing waters could penetrate the dense plastic clay. The crystals, in their growth, have distorted otherwise perfect fossil-plants, crowding parts of the fern-fronds to one side ; giving evidence that the deposition of the minerals was of later date than the preservation of the plant-remains. These plants were determined by David White to belong to a hori- zon near the middle, or the upper part, of the Lower Coal- Measures.*

Flora of the Outlying Carboniferous Basins of Southwestern Missouri," Bulletin of U. 8, Oeol. Sur., No. 98.

470 The Chemistry Of Ore-Deposition.

On the Mine La Motte grant, in Southeast Missouri, deposits of disseminated galena in black shale of Cambrian age outcrop at the surface, and were worked for lead during the early period of raining in that region. The galena occurs in crystal- line nodules, from i to in. in diameter, thickly distributed in bands through the shale. This shale-bed appears to be a local formation. The ore-deposits closely resemble in mode of occur- rence those of disseminated lead in the Cambrian limestone in the belt extending from Mine La Motte, through the Flat River district, to Bonne Terre.

The secondary formation of metallic sulphides is now taking place in the Missouri mines ; blende and galena, oxidizing to sulphates in the ore-deposits near the surface, are carried in solution by the subaerial waters to the deeper horizons, and there regenerated by the deoxidizing action of bituminous matter. The subject is too extensive to admit of discussion here, and must be left for a future paper.

A single instance, however, may be cited of the reproduction of blende from mine-waters. An old tunnel, driven through bituminous shale on the Banker's Tract, near Joplin, became filled with water draining from adjoining mines on which work had been suspended. The tunnel remaine< closed and submerged for ten or twelve years, until the mines were un- - watered in 1898. When reopened, the surface of the shales, on the roof and sides of the tunnel, was found to be thickly encrusted with minute crystals of blende, one- or two-hun- dredths of an inch in diameter. In places, the blende was de- posited on the pick-marks made when the tunnel was run.

The paper of T. A. Rickard, on " The Enterprise Mine, Rico, Colorado,"* shows the existence of a strongly-marked resem- blance between the occurrence of the flat ore-deposits at Rico, carrying silver and gold, and the ore-formation of Southwest Missouri, where galena and blende occur in simple runs, and also in compound runs, formed in like manner, in the favorable beds, by mineral-depositing solutions introduced through ver- tical fissures from an unknown source in depth, and where bituminous matter, contained in the ore-bearing strata, has likewise been the precipitating agent in the deposition of the ore.

♦ !ZVan., xxvi., 906-980.

The Chbmistry Of Orb-Dbposition. 471

Experiments made in the laboratory, to determine the re- ducing action of the black shale associated with the ore-bodies, are described by Rickard, as follows :

" A piece of the Rico shale was put into a weak solution of sulphate of silver (Ag,804) containing some free acid intended to neutralize the lime (CaCO,) in the shale. The precipitation of metallic silver became visible in three days. The parallel experiment with gold was more interesting. A piece of ore {assaying 1147 oz. of gold per ton) obtained from Cripple Creek, was taken, and its gold was extracted by a solu- tion containing ferric sulphate (Fe,0j,8S0,), common salt (NaCl) and a little free acid (H,SOJ. This Cripple Creek ore car- ried the black oxide of manganese (MnO,) in visible quan- tity, and thus the chlorine used to form the gold-solution was liberated in a manner simulating natural conditions. Of the gold, 99.91 per cent, was extracted and subse- quently precipitated on the Rico shale by inserting the latter in the solution thus formed. The gilding of the black shale by the deposit of gold became visible within four hours.''*

"W. Nicholas has made a series of similar experiments in the precipitation of gold by black carbonaceous shales from the Victorian quartz-reefs, f

The peculiar vein-formation known as the " Indicator " is an example of the localization of rich deposits of free gold, due to the reducing a<;tion of carbonaceous shales. Rickard defines the Indicator as " a very thin thread of black slate, which is remarkable on account of its extraordinary persistence, and also because the quartz seams which cross it are notably en- riched at the point of intersection.'' It is also referred to by Dr. Don.§ The Indicator is the most important member of a series of thin seams of black shale, more or less impregnated with pyrite and arsenopyrite, traversing the slate and sandstone formation of the district.

Different views have been expressed as to whether the car-

♦ Ibid,, pp. 978, 979.

t The OrigiD of the Gold-Bearing Quartz of the Bendigo Beefs/' bj T. A. Bickard ; Discoasion, Trans. , zxii., 762-763.

" The Origin of Gold in Certain Victorian Quartz-Beefs/' by William Nichohis, JBng. and Min, Jour., vol. xxxvi., pp. 367, 368.

t ''The Indicator Vein, Baliarat, Australia," Tram., xxx., 1010.

I The Genesis of Certain Auriferous Lodes," Tram., xxvii., 56&-572.

472 Thb Chemistry Of Ore-Deposition.

bon or the pyrite in the Indicator seam was the reducing agent in the formation of the rich bunches of gold-ore. But pyrite was deposited in the black shale by the reducing action of the organic matter ; so that, in any event, it was the presence of carbon compounds which, directly or indirectly, caused the local accumulation of the gold.

Owing to the far more powerful action of the hydrocarbons, reduction by pyrite contained in carbonaceous shales must al- ways be subordinate, even where local conditions, such as the presence of free oxygen and oxidized metallic salts, admit of the pyrite being decomposed. Any ferrous sulphate produced, at once re-forms pyrite, giving up its oxygen to the carbon. In the depths of the strata, below water-level, wherever any form of carbon is in excess, it absolutely protects the pyrite by con- suming all the free oxygen.*

Many instances might be cited to illustrate the influence of the organic matter contained in bituminous shales upon the formation of ore-deposits.

A stratum of black shale in the Mono silver-mine, Dry Canon, Utah, formed the hanging-wall of the rich ore-shoot, from which large masses of horn-silver and high-grade sulphide- ores were mined, carrying from 500 to 3000 oz. of silver per ton. It is reported that a carload of ore from this mine yielded over $55,000.

Emmons says: 'Most famous, in view of the enormous values taken from them, are the rich silver-bodies of the MoUie Gibson and Smuggler mines of Aspen, Colo. ; but, in their case, there is suflSicient organic matter present to explain the reduc- tion of the oxidized solutions to sulphides. They occur along a vertical fault, formed since the original mineralization of the district, and consist of great masses of polybasite and pink barite, which, in places, have been further reduced to native- silver. On one wall of the ore-body is the limestone, of which it is a replacement, and on the other a black bituminous

shaTe."t

Rickard, discussing this subject, writes : " The idea of the

This subject is discussed in more detail, under the sub-head, Protective Ac- tion of Carbon and of Hydrocarbons, AnUf p. 451.

t 'The Secondary Enrichment of Ore-Deposits,'' Trans,, zzx., 195. See, also,. QenetM of Ore- pp. 460, 4ol.

The Chbmistkt Of Ore-Dbposition. 473

precipitation of the ore through the agency of carbonaceous matter has been advanced in connection with ore-deposits in other regions. I may quote, as instances, the black Silurian slates of Bendigo, Victoria; the Devonian slates of Gym pie, Queensland ; the Jurassic slates of the ' Mother Lode ' region in Calaveras and Amador counties, California; the black shale enclosing the gold-specimen ores of Farncomb Hill, Brecken- ridge. Summit county, Colorado ; . . . and the celebrated Indi- cator series of Ballarat, Victoria."*

In this connection, reference is made to the well-known oc- currence of copper-ores at Mansfeld, Prussia, in beds of bitu- minous slate and bituminous limestone. Certain of the lower limestone beds are fetid. These copper-bearing formations extend over a large districtf The ore contains so much bitu- minous matter that only a little brushwood is required in roasting the ores in piles.

Limestones Containing Organic Matter.

In mining-regions where the ores occur in limestone, it is observed that in most instances the largest and most produc- tive mines are in belts or zones of crystalline limestones which are either exceptionally pure lime-carbonates or, more fre- quently, dolomites with only a small amount of insoluble mat- ter. Such formations, peculiarly favorable for ore, are rocks easily crushed by movements of disturbance, readily permeated by circulating-waters, and, from their chemical composition, rapidly attacked by solutions carrying carbonic acid. Where situated at the surface, they are cavern-forming limestones. Further, it is noted that both the magnesian limestones and the pure lime-carbonates usually contain some form of organic matter which, though small in amount, appears to have strongly influenced the deposition of the minerals in the strata.

Otherwise stated, ore-deposits in limestone, irrespective of the nature of the minerals constituting the ores, conform to the general law of selective deposition, namely, that " Some geological formutions appear to be everywhere barren of ore ; others occasionally carry snuill deposits workable where the conditions are

"The Enterprise Mine, Rico, Colorado," Trans., xxvi., 978. t Von Cotta, Treatise on Ore-DeposUsy Prime's Translation, p. 164.

474 The Chemistry Op Orb-Deposition.

exceptionally favorable ; but in each mining region certain strata are ore-bearing in a degree exceeding aU other formations coTnAined"*

Among the causes that have induced the concentration and deposition of the ores in special formations, prominence may rightly be given to the deoxidizing action of the bitumen, bi- tuminous coal, lignite, or other form of carbonaceous matter disseminated in the rock.

In Southeastern Missouri, the lead-ore now mined is mostly from deposits of disseminated galena in the dark-colored mag- nesian limestone, rich in bituminous matter, of the Cambrian formation at Bonne Terre and the Flat River mines. Prac- tically all the zinc-ore, and the greater proportion of the lead, produced in the Joplin region, in the southwest part of the State, is yielded by the Cherokee limestone, the upper division of the Subcarboniferous.f The Cherokee is a soft, crystalline, pure lime-carbonate, carrying bitumen. Its average composi- tion, from a number of analyses, is as follows :

Lime, 55.00

Magnesia, 0.23

Alumina, 0.10

Protoxide of Iron, 0.05

Protoxide of Manganese, . . . . . 0.02

Bitamen and insoluble, 1.00

Carbonic acid, 43.60

In the Upper Mississippi lead-region the productive formar tion has been the Galena limestone, the upper member of the Trenton. It is a soft, crystalline dolomite ; bituminous matter is present in relatively small amount, yet apparently more than sufficient to effect the precipitation of the metals and preserve the ores from oxidation below water-level. The deposits of blende in the mines near Mineral Point and ShuUsburg, Wis- consin, occur in the underlying " Blue " limestone of the Tren- ton, and the ores are concentrated about the intersection of the mineral-bearing fissures with thin strata of brown shale, sat- urated with petroleum, — the " Oil-rock" of the miners. J

The Lead- and Zinc-Deposits of the Mississippi Valley,'' by W. P. Jenney, Trawi., xxii., 187-188.

t "The Lead- and Zinc-Deposits of the Mississippi Valley," by W. P. Jenney, IVorw., xxii., 188.

t William P. Blake, Discussion of "The Lead- and Zinc-Deposits of the Mis- sissippi Valley," Trans. y xxii., 631.

The Chemistry Of Orb-Deposition. 475

A summary review of the occurrence of zinc- and lead-ores in the Mississippi valley shows that the formation of the de- posits has been due to solutions of normal temperature ; and that the chief agent in the primary deposition, and in the sec- ondary enrichment of the ores, has been the bituminous sub- stances contained in the strata in which the deposits are found. The larger part of the minerals constituting the ores has been deposited either by crystallization or by crystalline growth in the lime-rock or dolomite of the walls, or has impregnated the beds of specially favored geological formations.

In the limestone-area at Tintic district, Utah, the productive mines occur in two distinct belts in the Carboniferous forma- tion ; one, extending through the central part of the district, of dark-colored, magnesian limestones; the other, travers- ing Godiva mountain, on the eastern border of the lime-area, formed by beds of gray limestone with only a trace of mag- nesia.

On the central belt are situated the Gemini, Bullion-Beck, Eureka Hill and Centennial Eureka mines ; and farther south, also in magnesian limestones, are located the Grand Central and the Mammoth. A number of these mines have been worked continuously since the early development of the district in 1870-71. All have reached a depth of 1000 to 1750 ft. ; the Mammoth is now 2100 ft. deep.

It is not necessary to discuss the occurrence of the ore, be- yond its relation to the magnesian limestones in which the de- posits are found. Locally, these limestones vary somewhat in character ; they are hard, crystalline, bluish-gray to bluish-black dolomites, the color being due to organic matter. In certain places the beds are filled with nodules and thin bands of hard, black chert. The average composition, from 7 analyses, of the limestones in the vicinity of the Bullion-Beck mine is (the organic matter and loss being estimated by difference) :

Calcium carbonate, 48.76

Magneeinm carbonate, 35.43

Ferrous carbonate, 2.61

Silica, 9.67

Alumina, 3.00

Organic matter and lo8S, 0.53

In a number of analyses the silica varied from 6.75 per cent.

476 The Chemistry Of Ore-Deposition.

to 13 per cent., and the total insoluble matter from 16 per cent, to 18 per cent.

The amount of silica and insoluble matter is remarkable for there is every evidence in the mines that these dolomitic limestones are rapidly decomposed and eroded by carbonated waters. The explanation of this marked solubility of the dolomite, notwithstanding the large proportion of impurities, is probably to be sought in the structure of the rock. In the upper levels of the Bullion-Beck and the Eureka Hill mines, where the subterraneous erosion by surface-waters has been greatest, large masses of residual dolomite sand, which have resulted from the disintegration of the fissured and shat- tered beds, occur, filling cavern-spaces or chambers in the lime- stone. Beneath the heavy wash of boulders filling the gulch,, the limestone beds, for a depth of near 100 ft., without change in the stratification, are decomposed and altered in situ into soft, sandy dolomite, stained with iron and manganese oxides. Analyses showed that this decomposed rock had substantially the same composition as the loose deposits of sand; being dolomite, with the residual silica, clay, oxidized iron and man- ganese contained in the original formation. Surface-waters, carrying carbonic acid, appear first to attack the calcareous cement between the crystalline grains of dolomite, at the same time oxidizing the carbonates of manganese and iron present, and in this way rapidly disintegrate the rock.

Many caverns, mostly of small size and usually more recent in formation than the ore-bodies, occur in the limestone. It is noted that they are generally located along the course of the vertical faulting-fissures, which have been the channels fol- lowed by the solutions depositing the ore, the shattering and brecciation of the beds, due to the faulting movement, in- creasing the action of surface-waters in the erosion of the rock.

In a few instances the ore actually fills pre-existing caverns. The largest of these caverns in the Bullion-Beck mine, formed before the minerals were introduced in the primary deposition, was filled with argentiferous galena, in great part deposited by crystallization. The rock-floor of the cavern was covered by a horizontal stratum of chert nodules, overlain by sand-beds, 10 to 15 ft. in thickness, with disseminated pyrite and galena, the

Thb Chemistry Of Orb-Dbposition. 477

massive crystalline lead-ore resting on the sedimentary beds. The flat-beds covering the clay floor were unquestionably formed from the residual sand and chert contained in the rock, dis- solved away by the circulating-waters in making the cavern. Such occurrences of ore deposited by crystallization are rare in these mines ; practically all the quartz, and nearly all the lead- and copper-ores, are formed by replacement.

The limestones are much purer in the Grand Central and Mammoth mines. An average of 6 analyses gave (ferrous car- bonate, alumina and organic matter not determined) :

Calciam carbonate) 55.88

Magnesium carbonate, 42.84

Saica, 0.66

Undetermined and loss, 1.18

This is a bluish-gray, brown, or bluish-black, crystalline dolo- mite, free from chert. The weathered outcrop of certain beds shows the rock to be made up of the broken and water-worn joints of minute crinoid stems, one- to three-hundredths of an inch in diameter, with fragments of shells and an occasional small coral. The stratification is generally preserved ; in some places the rock is cross-sheeted by movements of disturbance, and locally the beds have been brecciated and recemented by their own attrition material into a massive rock, with but traces of bedded structure.

This limestone, even where not mineralized, is easily distin- guished by the appearance and fracture of the rock, — being dark-colored and crystalline, with spots and small vugs of cal- cite and stains of iron and manganese oxides on the joints. It is often sonorous, giving a clear metallic ring when struck with a pick. It crumbles under a blow into small, ragged, rough fragments, having the fracture of loaf sugar.

The beds are thin, brittle, easily shattered and crushed by fault- ing-movements. On account of the absence of clay in the rock, the breccias and attrition-material produced are permeable to circulating-waters; even small fissures and fractures in the lime keep open. Caves of considerable size are not infrequently encountered in the formation, but appear to have been formed subsequent to the ore. It is noteworthy that deposits of loose

478 The Chemi8Trt Of Ore-Deposition.

dolomite-Bands are seldom formed in this pure dolomite; neither is the rock usually altered in place to iron-stained rotten crlo- mite. The action of surface-waters is to dissolve the rock com- pletely, and not to disintegrate the rock by attacking the calca- reous cement between the grains.

The ore-bodies afford evidence that this limestone, especially where fissured and fractured, is easily replaced by silica and by the other gangue-minerals, ankerite, siderite, barite and calcite. Not only has the limestone been metasomatically replaced by primary sulphide-ores, carrying lead, copper, iron, arsenic, silver and gold, but the complex products of their oxidation and redeposition have, also, more or less perfectly replaced the rock. It is observed that the darker and coarsely crystalline lime-beds are highly favorable for ore, — beds made up of com- minuted fossil-remains, crinoid stems, broken corals and shells.

Eliminating the highly impure sediments, which seldom carry workable deposits, the structure of the rock appears to be far more important than the chemical composition in de- termining whether certain strata are ore-bearing or barren. Analyses of the magnesian limestones over a broad belt show that they vary but little in composition. The beds which have been found to be unfavorable for ore are usually dense, finely crystalline and impermeable; the rock generally breaking under a blow of a hammer with a " dead " sound, and a smooth, splintery fracture, like the fracture of quartzite. Organic mat- ter is not at all prominent in this limestone, although it gives the color to the rock.

The principal ore-bearing formation in Godiva mountain is a stratum, 200 to 400 ft. in thickness, of massive, gray, very coarsely crystalline limestone. It is a pure lime-carbonate, carrying some undetermined form of bituminous material, which gives to the rock, when broken, a sulphurous, fetid odor. On dissolving the limestone in acid, the bitumen sepa- rates in clots. An analysis of this limestone gave (the organic matter and loss being estimated by difference) :

Calcium carbonate, 98.76

Alumina and iron-oxides, 0.40

Silica, 0.20

Magnesia, trace.

Organic matter and loss, 0.65

The Chbmistrt Of Orb-Deposition. 479

The weathered outcrop of the gray limestone is, in many places, bluish-black from the concentration of the bitumen in the surface of the rock. The beds are formed of water-worn grains and broken fragments of small shells. A coral (zaphren- tis), 1 to 2J in. long, is its characteristic fossil. It exceeds in chemical solubility all other ore-bearing limestones in this sec- tion of the district The perfect manner in which great masses of the rock are replaced by the ore is evidence of this.

The gray-limestone formation extends northerly and south- erly through the whole length of Godiva mountain, bounded on either side by limestones more or less magnesian in charac* ter. Many of these magnesian limestones, interbedded in the series, are highly impure sediments, with 25 to 85 per cent, of silica, 5 to 10 per cent, of iron and alumina, 6 to 12 per cent, of magnesia, and 20 to 30 per cent, of lime. These formations- have been found unfavorable for ore.

On this gray-lime belt are located the Uncle Sam, May-Day and Yankee Consolidated mines, — properties developed since 1897. The deepest workings have attained a depth of 800 ft. The Uncle Sam mine has been noted for its large output of high-grade lead-ore, carrying silver, in a gangue mainly com- posed of lime-carbonate.

Quartz-ores prevail in the other mines of the belt, with lead, silver, and usually a small amount of gold.

The ores have been introduced in the strata through belts of nearly vertical faulting-fissures. Along the course of these fissures the ore-bodies have formed in the limestone. In some places the ore-deposits take on the form of fissure-veins, the ore being confined within the walls of the fissure and deposited in a more or less tabular sheet, pitching like the ore-shoots in quartz-veins in the metamorphic rocks. More commonly the faulting movements forming the fissures have so fractured the beds timt the mineral deposits are not limited by the fissure- walls and extend irregularly into the limestone. The largest ore-bodies have formed in spaces of multiple fissuring, where the belt of master-fissures cuts through lime-beds, broken and rifted in different directions by the complex intersection of sheeted belts, due to cross-fissures and to diagonal fissures.

The ores of primary formation are mostly deposited by re- placement of the limestone. Quartz occurs in many varied

480 The Chbmi8Try Of Ore-Dbposition.

forms, — from maseive limestone, more or less completely altered to quartz, with little change in structure, to the white, crystal- line mineral, grading insensibly into soft, crumbling, pulveru- lent quartz, in appearance resembling granulated sugar.

In certain places in these mines the limestone appears to have been sheeted and broken into large, thin and sharp frag- ments before it was replaced by the ore ; the sharp edges of the pieces of limestone were not rounded in the conversion ; there has not been any solution of the rock without the per- fect pseudomorphic replacement of its structure by the min- erals.

This has occurred not only in the replacement of the lime- stone by quartz, but also in its replacement by massive argentif- erous galena, as fine-grained in its crystalline structure as steel. The galena reproduces the shape of the original lime- stone fragments, so that they are fossilized by lead-sulphide, as wood is petrified by the infiltration of silica, only less per- fectly.

The largest body of galena of this character occurred in the Uncle Sam mine. The ore-body, 50 ft. long, 18 to 20 ft. wide, and 50 to 60 ft. high, was formed entirely of pure lead-sulphide, with no other minerals except calcite and the lime wall-rock. The ore averaged 75 per cent, of lead and 50 oz. of silver per ton. In this ore-body the massive limestone, prior to its min- eralization, had been fractured vertically in large, sheeted frag- ments, some of which would measure 10 to 15 ft. long and 10 to 25 ft. high, but only 6 to 16 in. thick. Even the largest masses of rock were altered throughout to steel-galena. Nu- merous vertical open seams and fractures, from the thickness of a knife-blade to 2 in. in width, separated these irregular sheets of ore one from another. A vertical fracture, 12 to 18 in. wide, passed through the ore-body ; it was more recent in formation than the primary ore and was filled with coarsely crystalline galena, with cleavage faces 2 to 8 inches across, de- posited by crystallization.

In general, in the mines on Gk)diva mountain, fine-grained galena, replacing the limestone, is of primary origin, while coarsely crystalline galena is usually secondary ; although some of the lead-ore deposited by crystallization (or crustifi cation) appears to be primary.

The Ghbmistrt Of Ore-Deposition. 481

Review of the Phenomena of the Deposition of Ores in Limestone. — A study should be made of the structure of the ore-bearing limestones, with the special object of determining the causes that have made certain strata favorable for ore, while other beds in the same geological formation, having an almost iden- tical chemical composition, and so situated that they are trar versed by the same fissures, through which the mineral-depos- iting waters have been introduced, have remained barren. In many instances the productive and the barren strata are inter- bedded and so situated that the ore-bearing fissures cut through all the beds alike, without any change in this selective deposi- tion of the ores.

Analyses of thede ore-producing limestones are needed to determine the amount and character of the carbonaceous sub- stances present, and also the minute traces of other elements, some of which may be found to have had an influence on the formation of the deposits. That such an influence may have been exerted seems probable, when we consider the enormous masses of the highly soluble limestones that have been dis- solved or replaced in the creation of the ore-bodies. It has been shown, for example, that the small percentage of bitu- men or other hydrocarbon contained in the rock, and set free by its dissolution, has strongly aided in the deposition of the ore.

Prof. Church, discussing the deposition of ores in limestone, says: "The operation of solutions whose composition we do not know can be judged only by their eflects. When metaso- matic replacement takes place in limestone, it is generally as- sumed that lime-carbonate goes into solution, while its place is taken by the ore-substances, — that is to say, that the action is molecular substitution, and not atomic ; but it is conceivable that the change should begin by an interchange of acidic ele- ments— that SiOj should drive out COj. Subsequent changes might remove the lime-silicate by another process of substitu- tion, since it is more soluble than silica;* but the point is that COj would be liberated, and, though the original ore-solution were free from CO,, it would immediately become charged

In the Tintic mines, lime-silicate does not appear to have been formed ; the silica directly replacing the lime-carbonate, or the carbonate of lime and magne- sia, as the case may be.

482 The Chemistry Of Ore-Deposition.

with that agent and exert the well-known dissolving power of carbonic acid solutions. In this way a solution which would have but feeble power in other rocks may in limestone set up a chain of reactions that would intensify its effects. . . . Lime- stone contains the elements for self-destruction, since the breaking-up of one lime-carbonate molecule may cause the solution of another; and as this cannot be said of any other rock, we reach a possible explanation of the comparative fre- quency of ore-bodies in limestone. The dolomites would, of course, present similar reactions." Prof. Church continues, respecting " The selection of a favored stratum for ore-deposi- tion. In some situations the solutions, before reaching the stratum of actual ore-deposition, must have passed several strata suitable for their action, if they had possessed from the beginning the power of solution which they showed ultimately. . . Ore-solutions exhibit a selective power which is extraordi- nary in a water fully supplied with dissolving qualities, but quite explicable in a solution which lacks this power."*

Many contributory causes have in all probability co-operated in the deposition of the ore, such as decrease of pressure and reduction in the temperature of the solutions, the mingling of mineral-bearing waters of different chemical composition enter- ing the limestone formation through distinct fissured belts, etc.; but the important factor appears to have been the great solu- bility of these limestones and dolomites in the waters which brought in the minerals, joined with the chemical activity of the contained hydrocarbons released in the dissolution of the rock.

In the solution of the limestone, the incidental liberation of large volumes of carbonic acid, ever dissolving more and more of the rock, set free a constantly renewed supply of car- bonaceous matter, whose function was to remove all free oxy- gen and reduce the sulphates in the waters to sulphides. At the same time, the calcium- and magnesium-carbonates, when dissolved, neutralized the acids and destroyed the chemical equilibrium, so that the mineral-saturated waters could no longer hold the metals in solution, after the addition of the elements derived from the limestone. The combined action of

Ometis of Ore-Deponta, pp. 196, 197. Trans,, vol. xxiii., 696, 696.

The Chbmistry Of Ore-Dbposition. . 488

the carbon, hydrogen, lime and magnesia contained in the rock was to deoxidize the solutions and bring them to the "critical-point," when deposition of the ores rapidly took place.

In conclusion : The ores of primary formation in the Tintic mines have been, in most of the occurrences, deposited from highly heated solutions by the metasomatic replacement of the limestone; only in relatively subordinate amount have the metallic sulphides been formed by crystalline growth in the rock, or by crystallization in the interspaces of the ore- bodies.

In the instance cited, in the Uncle Sam mine,* in the large body of steel-galena, without quartz, replacing the fractured lime strata, the deposition seems to have been from solutions either free from silica, or more probably of so low a tempera- ture that the chemical reaction in the substitution of quartz for the lime-carbonate could not take place.

In Tintic, the limestones, when unaltered, retain the included carbonaceous matter deposited with the sediments. In the ore- bodies, all forms of the hydrocarbons have been destroyed, either in the primary formation of the minerals or in the sub- sequent oxidation; the deepest mines in the district (1700 and 2100 ft, vertical depth) not having reached ground-water level.

Whatever may have been the r6le of the volatile hydrocar- bons in the original creation of the deposits, no evidence has been found of their ever having been present. Tintic district has been a center of intense volcanic activity, and it seems almost inevitable that, with the presence of notable quantities of bituminous matter in the rocks, volatile hydrocarbons would have been formed.

Many examples might be given of limestones, especially of magnesian limestones, which carry more or less organic matter and constitute the favored geological formations in the selective deposition of the ore. The zinc- and lead-deposits of Missouri and the lead- and copper-ores of Tintic District, Utah, carrying silver and gold, were chosen, owing to the author's more de- tailed acquaintance with the ore-deposits of those regions.

See anUj p. 480. VOL. XXX in. —30

484 The Chbmistrt Of Ore-Dbposition.

Petroleum.

The occurrence of petroleum in the Redington quicksilver- mine, New Idria, California, is reported by Luther Wagoner.* He says : Mineral-oil occurs in considerable quantity, a barrel of forty gallons being collected in one drift. It was used for lubrication of the machinery."

. Prof. Egleston, writing of the quicksilver-mines in northern California, says : At the Rattlesnake mine, near Pine Flat, where large quantities of metallic mercury are found, the rock contains so much petroleum that it has been necessary to make special arrangements to burn the carbides of hydrogen, since the distillation of the petroleum causes an extra quantity of poor soot to be formed in the condensation-chambers. "f

At the zinc- and lead-mines near Shullsburg, Wisconsin, thin partings or beds of brown shale, highly charged with petro- leum, are found in the Trenton limestone. Prof. Blake, dis- cussing the peculiar occurrence of this shale, known as the " oil- rock," says : " We find that this petroleum-shale, this horizon of hydrocarbons, is to-day the chief lower horizon of deposi- tion of the lead- and zinc-org s. Certainly, if this shale did not influence or determine the original primary accumulation of the ores, it appears to have exerted a very important influence upon the secondary or later deposition, from solutions perco- lating downwards."!

In the mines at Silver Reef, Utah, an oily substance, sup- posed to be petroleum, is reported to have occurred in the re- fractory ores at water-level. §

Rudolf Keck notes the association of organic matter with ore-deposits. He says : " Organic matter occurs in the state of asphaltum in the cinnabar mines in the Bavarian Palati- nate ; in that of petroleum, in the mines of California, Ievada and Hungary ; in that of anthracite and graphite, in mines in Transylvania, Portugal, Derbyshire, Calcutta, Saxony, Baden,

Geology of the QuicksUver- Mines of California,*' by Luther Wagoner, Eng. and Min, Jour. , vol. xxziv. , p. 334.

t Notes on the Treatment of Mercury in North California," by T. Egleston, Trans,, iii., 273.

I William P. Blake, Discussion of the Lead- and Zinc-Deposits of the Missis- sippi VaUey," Trans., xxii., 631. See anU, pp. 462-466.

II '' The Genesis of Ore-Deposits,'' by Rudolf Keck, Eng, and Min, Jour., vol. XXXV., p. 3.

The Chemistry Of Orb-Dsposition. 485

Bitumen.

The occurrence of bitamen, and its influence in the forma- tion of the zinc- and lead-deposits in the Cherokee limestone, in Southwest Missouri, has already been discussed.*

Becker notes the existence of bitumen in the Manhattan, Knoxville, Phoenix, Oathill, Manzanita, Great Western and Great Eastern quicksilver-mines, and also at Sulphur Bank, California. At the Phoenix mine, a peculiar non-oxygenated hydrocarbon (napalite), with 90 per cent, of carbon and 10 per cent, of hydrogen, occurs quite abundantly, f

Luther Wagoner, in an article on the geology of the quick- silver-mines of California, says : " Oil (petroleum), more or less oxidized, is observed in all mines of quicksilver on this coast, and in general is found as bitumen or a thick tar.'* J

Prof. Christy thus describes the occurrence of bitumen at New Almaden, Cal. : " The ore at New Almaden is cinnabar. Native quicksilver occurs also ; but, as a rule, in small quanti- ties only. Pyrite occasionally accompanies the ore. Bitumen is quite common, sometimes as a fragile, black, lustrous solid, resembling soft bituminous coal, but melting easily, like tar ; at other times it occurs in the vugs of the gangue, in a liquid state, like coal-tar. I have found lumps of apparently pure cinnabar from the New Almaden to give a voluminous residue of pulverulent charcoal, when subjected to sublimation out of contact with the air. This would seem to show that the bi- tuminous substance is intimately associated with the cinna- bar." §

Marsh-Gas (CH,).

In the quicksilver-mines of California marsh-gas was discov- ered by Becker. In the Phoenix mine, on the 150- and 300-ft. levels, inflammable gas, mainly composed of marsh-gas, issues from cracks in the rock.|| At Sulphur Bank, California, 79

See anU, pp. 445, 446.

t "Geology of the Quicksilver-Deposits of the Pacific Slope/' by Geo. F. Becker, U. S, Oed, Sturv,, Monograph xiii., pp. 371, 372.

t ''The Geology of the Quicksilver-Mines of California," by Luther Wagoner, Eng, and Min, Jour.f vol. zxxiv., p. 334.

I " Quicksilver-Beduction at New Almaden," by Samuel B. Christy, 2Van., xiiL, 547-.548.

II ''Geology of the Quicksilver- Deposits of the Pacific Slope,'' by George F. Becker, p. 373.

486 The Chbmi8Trt Of Orb-Deposition.

parts of marsh-gas were found in 1000 parts of the gases es- caping with the ore-depositing waters.*

Flows of gas under heavy pressure were struck in the deeper levels of the Silver-Islet mine, Lake Superior. Subsequently,, in extending the levels, vugs and cavities in the vein were found, lined with crystals of galena and calcite, in which the gas had probably been stored. In sinking the shaft, gas wa also encountered in the slate, and it appears to have per- vaded the country-rock below the 8th level (440 ft., vertical depth). The gas was associated with small flows of strong, acrid mineral-water, carrying much calcium chloride. It burned with a purple, blue, or yellowish flame, and was sup- posed to be light carburetted hydrogen, but it was never analyzed, t

Small quantities of hydrocarbon-gas are stated by Mr. B. Tibbey to have been struck in following the vein on the 300-ft level of the Illinois mine, Walkerville, Butte City, Montana. The gas burned with a bright-yellow flame, like ordinary il- luminating gas. This occurrence is remarkable, as the vein occurs in granite.

Review of the Action of Volatile Hydrocarbons. — In the Joplin, Mo., mines, the greater part of the bitumen set free by the ex- tensive subterraneous erosion of the lime strata is still pre- served in the ore-bodies below water-level, owing to the primary deposition having been effected by mineral-solutions of normal temperature. The same is also true of the petroleum occurring with the zinc-ore in the oil-rock in the Trenton limestone in Wisconsin, to which reference has been made. But in many ore-deposits in other mining-regions the heat accompanying the deposition has been so great, and the chemical activities so intense, that every trace of volatile hydrocarbons has been de- stroyed.

Petroleum contained in the strata may be decomposed by (1) destructive distillation, due to the earth-temperatures or ta the heat of the ascending mineral-solutions ; (2) by oxidation, the carbon and hydrogen forming carbon-dioxide and water ; and (3) by the action of sulphur, which dehydrogenizes the oil.

Ibid,y p. 258.

t ''The Silver- Islet Mine and Its Present Development/' by Francis A. Lowe,. Eng, and Min, Jour., vol. xzziv., pp. 320-323. See also anUf p. 453.

The Chemistry Of Ore-Deposition. 487

Petroleum and similar hydrocarbons, when heated and sub- jected to the action of sulphur at temperatures (in the case of the heavier oils) far below that at which distillation occurs, are rapidly decomposed, with formation of sulphuretted hydrogen and of oils with a greater proportion of carbon than the original oil ; or, if the sulphur be in excess, carbon is in some instances deposited.

The rSU of the volatile hydrocarbons in the primary forma- tion of mineral-deposits, especially where the deposition is due to igneous disturbances, has not received the attention it de- serves. Investigation is needed of the action that marsh-gas and other hydrocarbon-gases exert in the deposition of ores ; particularly in the formation of deposits of cinnabar, which are frequently associated with bituminous shale, bitumen and vola- tile hydrocarbons.

Marsh-gas has a theoretic reducing power one-half that of hydrogen and fifty per-cent. greater than that of pure carbon. In the formation of ore-deposits, directly induced by igneous action, temperatures must inevitably occur in the depths of the strata, such that gaseous hydrocarbons would act with great energy in the deoxidation and precipitation of the metals. Under like conditions, petroleum, and the volatile carbon com- pounds with high boiling-points, would exert a reducing power but little inferior, and, from the high specific gravity of their vapor, would displace steam and all other gases of less relative weight.

Vni. The Relative Reducing Power of Minerals.

Calculation of the Theoretic Reducing Powers of Various Organic and Inorganic Mineral Substances usually Occurring in Association mth Ore-Deposits Based upon the Weight of Oxygen Consumed,

The quantitative value, or amount of work accomplished in the formation of ore-deposits by the various reducing sub- stances, is measured by the weight of oxygen with which they unite. This work of deoxidation may be termed the of the reducing agent..

In calculating this duty for the more common organic and inorganic minerals which occur in ore-bodies or in strata in which ores were formed, or into which they were intro-

488 The Chemistry Of Orb-Deposition.

daced by the waters, either in the original deposition or in the secondary enrichment of the deposits, it has been found more convenient to make the values relative, assuming hydrogen, the most powerful deoxidizing agent, to have a value of 100. Let jR represent the relative reducing power, or duty, of anj mineral substance. Q be the weight of oxygen consumed by one part of the

mineral. S be the weight of the mineral required to unite with one

part of oxygen. P be the weight of hydrogen which combines with 100 parts of oxygen. The value of Q may be determined in each case from the chemical reactions which take place. Thus, for hydrogen,

2H+ 0 H,0, 2 + 16=18,

whence, by proportion, the weight of oxygen consumed by 1 part of hydrogen is determined.

2: 16:: 1 : Q=8.00.

R has been assumed for hydrogen as 100. In the case of carbon, the reaction is

C+0, Co„ 12 + 32 44,

whence, 12 : 32 : : 1 : Q 2.6666.

The relative power, or duty, of carbon compared with hydro- gen is

8: 2.6666:: 100: i?= 33.83.

For oxygen the value of P is determined from the weight of hydrogen that unites with one atom of oxygen :

0 + 2H H,0, 16: 2:: 100: 12.5.

P is a constant and always a minus quantity ; the oxygen combined with a mineral substance diminishing its reducing power.

The Chehistrt Of Ore-Dbpositiok. 489

Jt, Q and S are determinable by the following formulas:

8-' -"106' " C'

whence, by substitutioD,

From the above it is seen that in assuming, for convenience, the value of B for hydrogen as 100, it was equivalent to multi- plying the corresponding value of Q S) by 12.5. Conse- quently the several values of i?, being calculated for equal weights of the mineral substances, are in each instance the weight of oxygen which is consumed by 12.5 parts of the reducing agent. Thus, 12.5 parts of carbon consume 33.33 parts of oxygen, etc.

The " duty " of any compound substance is the sum of the reducing powers of the elements of which it is composed. Thus, for the hydrocarbons :

Let a the percentage of carbon, " " " hydrogen,

" " " oxygen.

Then B (33.33 a + 100 b) — 12.5 c.

By a formula of this kind B can be calculated directly from the percentage-composition of any substance. Even in the com- plex metallic sulphides, arsenides, etc., jR may be calculated from the composition by substituting in the formula the value of -ft for sulphur, arsenic, etc.

For carbon-monoxide the value of B may be calculated from the percentage-composition: carbon, 42.86; oxygen, 57.14.

0.4286 X 83.33 14.28 Less 0.5714 X 12.5 7.14

7.14 B. Or from the equations and proportions :

Co + 0 Co„

28 +16 44.

28: 16:: 1: (2=0.5714,

8: 0.5714:: 100: i2 7.14.

490 Thb Ohbmistry Of 0Be-Bbp08Iti0N.

MarshrOnSjCR. — Marsh-gas (methane) belongs to the paraffin series of volatile hydrocarbons ; its composition is

Carbon, 76.00

Hydrogen, 26.00

By oxidation, marsh-gas forms carbonic acid and water, :

Ch, + 0, H,Co, + H,0.

16 : 64 : : 1: 4.00. 8 : 4 : : 100 : J2 50.00. Or, calculated from the composition,

33.83 X 0.75 25.00. 100.00 X 0.25 25.00.

50.00 R.

Petroleum. — American petroleum is in great part a mixture of hydrocarbon oils of the paraffin series, represented by the formula CnH2n+2. The heavier oils average, approximately, carbon, 85 per cent. ; hydrogen, 15 per cent. ; corresponding very nearly to the formula, Assuming that the carbon is completely oxidized to carbonic acid, and the excess of hydro- gen to water:

C,.H„ + 0„ 16H,C0, + H,0,

from which R 43.36.

Bitumen. — With bitumen is included mineral-tar, maltha, and the solid oxygenated hydrocarbons, such as grahamite. Their composition, while variable, usually falls within the limits of the analyses No. 1 and No. 2 :

No. 1. No. 2. No. 3.

Carbon, 80.00 89.00 81.00

Hydrogen, 14.00 11.00 10.00

Oxygen, 6.00 0.00 9.00

100.00 100.00 100.00

The value of R for analysis No. 1 39.92, and for analysis No. 2 40.67. Analysis No. 3, of grahamite (gilsonite), with but 10 per cent, of hydrogen, gives a value for R of 35.88. In the above analyses it is probable that some nitrogen and sul- phur are included with the oxygen, so that the deduction made for oxygen is slightly too great.

The 0Hemi8Try Of Ore-Deposition. 491

Bituminous Coal. — The average composition of bituminous coal may be stated as falling within the limits of the analyses 1 and 2:

No. 1. No. 2.

Carbon, 81.00 88.00

Hydrogen, 4.00 7.00

Oxygen, 15.00 .6.00

100.00 100.00

The duty calculated from the composition in the above anal- yses is, for coal No. 1, J? 29.13 ; and for coal No. 2, iJ

Lignite. — The composition of lignite is extremely variable and is much affected by the amount of decomposition it has under- gone. Assuming that the analyses given below represent the ordinary limits of composition, the value of B for lignite No. 1 is 19.50, and for No. 2, 28.83.

No. 1. No. 2.

Carbon, 60.00 73.00

Hydrogen, 4.00 7.00

Oxygen, 36.00 20.00

100.00 100.00

Native Hwmis Acid. — Dana gives the composition of humus

acid from Bohemian brown-coal as which corresponds

to:

Carbon, 65.31

Hydrogen, 4.61

Oxygen, 40.08

998 : 1440 : : 1 : § 1.4428. 8 : 1.4428 : : 100 : J2 18.04.

Or, calculated from the composition,

0.5531 X 33.33=18.44

0.0461 X 100.00 61

Less 0.4008 X 12.5 5.01

18.04 R.

Sulphur. — Sulphur in ore-deposits may oxidize under cer- tain conditions to sulphurous acid, but usually sulphuric acid is formed.

492 The Chemistry Op Orb-Deposition.

S + O, SO, ; whence, It 12.50

rB 18.75

S + O, SO,; whence J Q 1.50

is 0.667.

Combined sulphur may, for convenience in calculating the duty of sulphides, be regarded as oxidizing to SO ; as if all the oxygen combined with the sulphur and none with the base giving the values B 25.00 ; Q 2.00 ; S 0.50.

Sulphuretted Hydrogen. — The complete oxidation of sulphu- retted hydrogen forms sulphuric acid, H,S + H,S04, from which iZ 23.53. When oxygen is deficient, water is formed with separation of sulphur. The reaction then is :

H,S + 0 S + 11,0 ; whence, B 5.88.

Pyrite and Marcasite. — Three distinct reactions may occur in the oxidation of pyrite and marcasite (FeS,) :

(1) With liberation of sulphur, and formation of ferrous-sul- phate—

FeS, + O, S + FeSO*; whence, B 6.67 ; Q 0.533 ;

1.876.

(2) With formation of ferrous sulphate and free sulphuric acid, one atom of sulphur may be regarded as oxidizing to SOs, the other to SO,—

FeS, 4- O, + H,Oi= FeSO, + HSO,; whence, B 11.67; Q 0.933; A? =1.072.

(3) When the oxidation of pyrite takes place with excess of air, ferrous sulphate is first formed, and by a complicated series of reactions, with further absorption of oxygen, the final result is the formation of limonite and sulphuric acid. The equation may be written :

4FeS, + 0, + 11H,0 2Fe,03,3H,0 8H,S0

Giving 12.50; 1.00; 1.00.

In the substitution of blende and galena for pyrite in secondary deposition, the reactions corresponding to equation (1) may be expressed :

The Chemistry Op Ore-Deposition. 498

FeS, + ZnSO ZnS + FeSO, + S. FeS, + PbSO, PbS + FeSO, + S.

Pyrite also deoxidizes sulphuric acid, with the formation of sulphuretted hydrogen and sulphur :

FeS, + H,SO, H,S + S + FeSO,.

The reduction of zinc- and lead-sulphate and lead-carbonate by pyrite is shown by the following equations, corresponding to equation (2) :

FeS, + ZnSO, + HO + 0, ZnS + FeSO, + H,SO,. FeS, + PbSO, + H,0 + 0, PbS + FeSO, + H,SO,. FeS, -f PbCO, + HO + O3 PbS + FeSO, + H,CO,.

In the presence of an excess of air, reactions, corresponding to equation (3), take place in the reduction of these soluble salts of zinc and lead, as follows :

4FeS,+ ZnSO,+ 11H,0 + 0„= ZnS + 2Fe,03,3H,0 + 8H,S0,. 4FeS, + PbSO, + 11H,0 + PbS + 2Fe,0„8H,0 + 8H,S0,. 4FeS, + PbC0, + IIHO + =PbS + 2FeA,3H,0 + H,CO,

H- 7H,S0,.

Arsenic and Antimony. — The values of B for arsenic and anti- mony are obtained from the following equations :

2As + 0, AsjO,; whence, 6.67. 2Sb + 0,= Sb,0,; whence, E 2.50.

Arsenopyrite. — The composition of arsenopyrite, FeAsS, is as follows :

IroQ, 34.30

Arsenic, 46.00

Sulphur, 19.70

The value of -B may be calculated either from the reaction, the arsenic oxidizing to AsjO,, or from the composition, as follows :

2FeAsB + 0„ AsjO, + 2FeS0,.

494 The Chkmistbt Of Orb-Dbposition.

326 : 208 :: 1 : Q 0.( 8 : 0.6S8 : : 100 : J? 7.98.

0.197 X 25 4.92 0.46 X 6.67 3.06

7.98 Jj.

Miargite. — For enargite, CuA.8S„ or 3Ca,S, A8,S„ the com- position and the computations are as follows :

Copper, 48.3

Anenic, 19.1

Sulphur, 32.6

3Cn,S, A8,S, + 2H,0 + 0„ As,0, + 6CuS0 + 2H,S0,.

One-fourth of the sulphur, or 8.15 per cent., is oxidized to SO,, and the remainder (24.45 per cent.) to S0.

786.4: 560 ::1 : Q 0.7121. 8 : 0.7121 :: 100: i2= 8.90.

0.0816 X 18.75 1.63 0.2446 X 25.00 6.11 0.191 X 6.67 1.27

8.91 It.

Stibmte. — For stibnite, Sb,Sj> the composition and the compu- tations are as follows :

Antimony, 71.4

Sulphur, 28.6

Dana gives the product of the oxidation of stibnite as valen- tinite, Sb,Oj.

Sb, -h 0„ + 3H,0 Sb,0, + 3H,S0,. 336: 192:: 1 : 0.5714.

8 : 0.5714 : : 100 : i? 7.15. Or, calculated from the composition,

0.286 X 18.75 5.36 0.714 X 2.50 18

The Chemistrt Of Ore-Deposition. 495-

Pyrrhotite. — Similarly for pyrrhotite, PeuS,, :

Fe,,S„ + 0„ +H,0 llFeSO, + H,SO„

Giving J? =9.40; 0.752.

Ferrous Sulphate. — The reactions in the case of ferrous sul- phate, FeS04, are as follows :

In the oxidation of pyrite and marcasite, a mixture of ferrous sulphate and free sulphuric acid is first formed. Weed* gives the products of the further absorption of oxygen as

H,80„Fe(0H), and FeSO,),.

The reaction that takes place may be written :

6FeS0, + 2H,S0, + 4H,0 + O, 2(H,S0„ Fe(0H)3) + 2(Fe,(SOJ3) -t- H.O.

Six parts of ferrous sulphate absorb 3 parts of oxygen ; or by reduction, 2 parts of ferrous sulphate absorb 1 part of oxygen.

304: 16 :: 1: 0.05263.

8: 0.05263:: 100: i2=0.66. 5=19.1.

Summary.

The following table of comparative reducing powers gives the quantitative value, or gross amount, of the work done by each of the deoxidizing agents. It is necessary, however, to supplement these theoretic results by observations in the field,, especially of ore-deposits undergoing decomposition and re- formation ; and also by experimental research in the labora- tory, in order to estimate accurately in each particular instance the chemical energy, or velocity with which the action takes place.

Fortunately, with respect to the greater number of the more important reducing substances commonly occurring in ore- deposits, the gravimetric power, or duty, and the chemical

"The Enrichment of Gold- and Silver Veins," by Walter H. Weed, Oenesis of OreI>epant8y p. 478 ; Trans., xxx., 429, 430.

496 The Chemistrt Of Ore-Deposition.

energy run nearly parallel ; so that one may be taken as the measure of the other.

The results of these calculations confirm the observations made in the zinc- and lead-mines of the Joplin, Mo., region, in the investigation of the secondary formation of the ores, of the relative order of the reducing powers of the principal de- oxidizing agents, viz. : 1, bitumen ; 2, bituminous coal and car- bonaceous shales ; 3, marcasite and pyrite ; 4, blende ; 5, ga- lena.

Ferrous sulphate appears to be exceptional ; notwithstanding the extreme low duty (0.66), and notwithstanding that, in form- ing ferric sulphate, 19.1 parts of the salt combine with only one part of oxygen, yet in the zone of oxidation, where the chemical activities have full play in the breaking-up of an ore- body, it fulfils a special mission, at once oxidizing and reduc- ing. Its chemical energy is such that it reduces cuprous oxide to the metallic state ; a change which none of the other deoxi- dizing agents usually found in ore-bodies are able to accom- plish.* Further, its field of operation is the zone of oxidation and that border-land where the zone of oxidation merges into the zone of reduction.

This low quantitative-value is in many instances more than offset by the large amount of ferrous and ferric sulphates con- tinuously supplied by the progressive oxidation of the pyrite in the ore-deposits. The mine-waters lixiviating the decom- posing ore, although the volume of the flow may be consider- able, are frequently strongly acid from the free sulphuric acid and iron sulphates held in solution.

In conclusion, the hydrocarbons, combining the highest quantitative deoxidizing power with an intense chemical activ- ity, are the most powerful of all reducing agents. The action of the solid oxygenated hydrocarbons, bitumen, bituminous coal, and the lignitic matter finely disseminated in shales, is greatly accelerated by the facility with which these carbon- compounds, when in powder, are carried by the circulating waters into every part of the ore-bodies.

" Enrichment of Gold- and Silver- Veins," by Walter H. Weed, Trans., xxx., 431 ; QenesU of Ore-DeponUf p. 480.

The Chemistry Of Ore-Deposition.

Table.

The Relative Reducing Power, J?, or Duty, of Equal Weights of the Organic and Inorganic Mineral Sub- stances Usually Occurring in the Ore-Bodies, or in THE Wall-Rock, or Introduced with the Circulating Waters; Hydrogen Being Assumed as 100.

Hydrogen (occurs combined with carbon), oxi- dized to H,0,

MarshrgaSj CH (carbon 75 per cent., hydrogen 25 per cent.), oxidized to H,C0s+H,0,

Petroleum CnH2n+2 (carbon 85 per cent., hydro- gen 15 per cent.),

Bitumen (carbon 89 per cent., hydrogen 11 per cent., oxygen 0 per cent),

Bitumen (carbon 80 per cent., hydrogen 14 per cent., oxygen 6 per cent.),

Bitumen (grahamite) (carbon 81 per cent., hydro- gen 10 per cent, oxygen 9 per cent).

Bituminous Coal (carbon 88 per cent, hydrogen 7 per cent., oxygen 5 per cent.),

Bituminous Coal (carbon 81 per cent, hydrogen 4 per cent., oxygen 15 per cent), .

Carbon (graphite, etc.), oxidized to COj,

Carbon oxidized to CO,

Lignite (carbon 73 per cent, hydrogen 7 per cent, oxygen 20 per cent),

Lignite (carbon 60 per cent., hydrogen 4 per cent, oxygen 36 per cent),

Native Humus Acidy (carbon 55 per cent, hydrogen 5 per cent, oxygen 40 per cent),

Sulphur (combined), oxidized to SO, .

Sulphur, oxidized to SO,,

Sulphur, oxidized to SOj,

Sulphuretted Hydrogen, H,8, oxidized to HSO,

Sulphuretted Hydrogen, HS, oxidized to H,0+S,

/oxidation of Fe to\

Pyrite and Marcasite, FeS, (2Fep,,3H,0 ; and S

\to SO, /

498 The Chbmi8Trt Of Orb-Deposition.

Pyrite and Marcasite oxidation to FeSO*, . . 11.6T

Pyrite and Marcasite oxidation to FeSO and S, . 6.67

PyrrhotUe, Fe„S„, oxidized to FeSO, and H,SO, 9.40 Enargite OujAsS*, oxidized to AsjO, CuSO and

H.'S0„ 8.9a

Chakopyrite, CuFeS,, oxidized to CuSO and

FeSO,, 8.72

CoveUite, CuS, oxidized to CuSO, . . . 8.89

Blende ZnS, oxidized to ZnSO, 8.25 Arsenopyrite FeAsS, oxidized to and

FeSO,, 7.98

Calcium Disulphide CaS, oxidized to CaSO and S, 7.69

Stibnite, Sb,8„ oxidized to Sb,0, and H,SO, . 7.1&

Carbon Monoxide CO, oxidized to CO,, . . 7.14 BarrdUj Cu,Fe8„ oxidized to CujSO, CuSO, and

FeSO,, 7.01

Arsenic oxidized to AsO, 6.67

Tetrahedriiey 4Cu,8.SbjSs, oxidized to Cu,SO,

CuSO, andSbA, 6.39

Iron, oxidized to Fep,, 5.86

Iron, oxidized to Fe,0, 4.76

Iron, oxidized to FeO, 3.58

Chalcocite, CujS, oxidized to Cu,80, . . . 5.04

Galena, Pb8, oxidized to Pb804, 3.85

Tellurium, oxidized to TeO„ 8.20

Copper, oxidized to CuO, 8.15

Copper, oxidized to Cu,0, 1.58

Antimony, oxidized to 8b,03, 2.50

Rhodochrosite, MnCO,, oxidized to Mn0„ . . 1.75

Sideriie, FeCO,, oxidized to Fe,0„ . . . 0.86

Ferrous Sulphate, FeSO,, oxidized to Fe,(SOJ„ . 0.66

Magnetite, Fe,0, oxidized to Fe,0,, . . . 0.46-

THB OAMP BIRD MINB, OURAY, COLORADO. 49ft

The Camp Bird Mine,* Ouray, Colorado, and the Mining and Milling of the Ore.

BY CHESTER WELLS PURINGTON, THOMAS H. WOODS AND GODFREY D. DOVETON, OURAY, COLORADO.

(New York and Philadelphia Meeting, Febraary and May, 1902.)

The Camp Bird Mine, Mining and Orb-Transportation.

By Chester Wells Parington.

JSituation, — The Camp Bird mine is in Imogene basinf (Pig. 1) at the bead-waters of Caiion creek, a branch of the Gunnison in the southern part of Ouray county, Colorado, towards the northern edge of the region known as the San Juan mountains, and about 10 miles W. of the continental divide. It is 8 miles by wagon-road from Ouray, the terminus of a branch of the Rio Grande Southern railway. The distance from Denver to Ouray is 887 miles by rail. In an air-line, the mine is 190 miles SW. of Denver. The altitude of the town, tunnel and buildings is 11,200 ft, and level No. 2 is 11,500 ft., and No. 1 is 11,670 ft., above sea-level. The lowest point of the lode-outcrop, which crosses the basin E. and W., has an elevation of 11,850 ft., and that of the highest point, on the divide between Imogene and Tomboy basins, is 13,250 ft. On the eastern slope of the Imo- gene basin (towards Ironton) the vein is less clearly defined on the surface.

Ownership and Extent — At the time of the writing of this paper, the property is owned by Mr. Thomas F. Walsh, and operated under the management of Mr. J. W. Benson. It

Since the receipt of this MS. by the Secretary, but prior to publication, the mine has been sold to an English company, and is known as the Gamp Bird, Limited.

t The map of the north-west portion of the Silverton Quadrangle accompanying this paper is a reproduction of a portion of that accompanying Bulletin 182 of the United States Geological Survey, 1901, Beport on the Economic Geology of the Silyerton Quadrangle, Colorado/' by Frederick Leslie Ransome. This work will be frequently referred to in the following description. The map is here repro- duced by permission of the Director of the Geological Survey.

X I wish to acknowledge many courtesies extended by the manager and his staff, enabling me to collect the data for this paper. VOL. xzxin. — 31

/;rr:'iiikiVi,iH.Miii

rbin

4J VanJtr

ICNCOwS ROCKS FAULT

eOCBNt AND NEOCCNC ,

MOMONITE POUPHYHY / WOir-SSOHf S

Wto.. Kr.U O °"'"

THAN LOOeS, CMIIFLV STOCM

Vcntical Loocs

Scale Of Miles

%m

mi

Qtiitr ft C9.,ll.t

Map Showing Situation of the Camp Bird Mine. Reproduced from Bulletin 182, United States Geological Survey. By Frederick Leslie Ransome. Geology by Whitman Cross.

For names of mines indicated by numbers on this map, see foot-note on opposite page.

The Camp Bird Mine, Ourat, Colorado. 501

comprises 129 patented mining-claims, covering more than 1000 acres, and a mill-site, 2 miles from the mine, in the canon towards Ouray.

History and Present Improvements, — The Camp Bird claim was located in 1896 hy Mr. Walsh, who in the same year bought the adjoining claims from H. W. Reed and others. The first work was done in the upper part of the present workings, A few men were kept working during the winter; and the fol- lowing season the old 10-stamp " U. S." mill, a mile down the canon, was utilized for milling the ore. The product steadily increased, and successive improvements were made as fast as development warranted. In 1898, buildings were erected at the present No. 2 level, and a 20-8tamp mill, the nucleus of the present 60-stamp mill, was built on the Camp Bird mill-site. The present extensive surface-plant, consisting of the compres- sor-house, electrical station, aerial tram and large boarding- house, was erected in 1899 at the tunnel-, or No. 8-level, where a cross-cut tunnel (to be described under the head of Under- ground Development) was driven 2200 ft., to cut the vein 800 ft. below the surface.

Climate. — The San Juan region has a dry and healthy cli- mate, the temperature ranging from 75° F. in summer to — 25° P. in the coldest winter weather. Much snow generally falls in winter, but the rainfall is not excessive at any season.

Topography. — Toward the northern edge of the San Juan mountains a rmsa country obtains, having a general elevation of 7000 ft., a part of the great basin draining into the Gulf of California. An abrupt rise of this plateau to heights of over 13,000 ft. is characteristic of the country about Ouray and to the south. The mountain country is, properly speaking, a par-

Kames of mines indicated by n ambers on Camp Bird map. Fig. 1 : 2. Revenue Tunnel. 8. Wheel of Fortune. 4. U. S. Depository. 5. Gamp Bird, Main Adit. 6. Camp Bird, Upper Workings. 7. Hidden Treasure. 8. Hancock. 9. Japan. 10. Tomboy, Main Adit 11. Tomboy, Upper Tunnel. 12. North Chicago. 13. Barstow. 14. Silver Bell. 15. Paymaster. 16. Amer- ican Girl. 17. White Cloud. 18. Guston. 19. Scotch Girl. 20. Kobinson. 21. Yankee Girl. 22. Grand Prize. 23. Midnight. 24. Carbonate King. 25. Alexandra. 26. National Belle. 27. Lake (Red Mountain). 28. Charter Oak. 29. Hudson. 30. Webster. 31. Galena Queen. 32. Mineral King. 33. Hen- rietta. 34. Carbon Lake. 36. Congress. 36. St. Paul. 37. Silver Ledge. 55. Poughkeepsie. 65. Mammoth. 88. Meldrum Tunnel. 89. Hammond TunneL Genesee-Vanderbilt 91. Summit. 94. Little Candies.

502 The Gamp Bird Mine, Ouray, Colorado.

tially eroded plateau, the numerous streams cutting down their valleys with a canon-like topography, forming precipitous slopes, and descending in torrents and cascades.

The heads of streams are found in comparatively flat hasius or cirques of glacial origin, the ice-action responsible for their formation being entirely local, extremely recent, and, in places, still in progress. The timber-line is at about 11,500 ft., and the cirques lying above this altitude are treeless.

The sharp descents (Figs. 2 and 7) of the mountains from 18,500 to 7000 ft. are of great advantage in mining operations. Exposures, for the most part perfectly bare, of the sedimentary and volcanic rocks, offer special facilities for prospecting and exploitation.

The valley of Canon creek, he.ading in Imogene basin, is thoroughly typical of the San Juan topography. From its source at 12,900 ft. down to an elevation of 9000 ft., 1 mile below the Camp Bird mill-site, the stream has an average fall of more than 800 ft to the mile. The amount of depth gained by the No. 3 level of the Camp Bird, i.e., approximately 1 ft. of depth for every 4 ft. of tunnel driven, may be taken as a fair average of the stoping facilities of the San Juan in general. It has rarely been necessary to resort to sinking in the mining operations of the region.

A remarkable feature, to which I have already referred,* is the presence, in the mountain-combs forming the divides, of jagged gaps, formed in large part by the weathering of the veins which cross them at various angles. Metalliferous zones so indicated do not, however, always prove to be of economic importance.

Geology of the District — quote from the paper already re- ferred to,t in order to give a general idea of the rocks and their relations :

'The San Juan mountains rise on the northern edge of the great plateau region which has such widespread development in southwestern United States. This plateau is composed throughout of nearly flat sedimentary heds, extending in geological age from those lying directly on the Archean to the latest Tertiary. This vast formation has heen in places tilted up, deformed, injected, and hroken through hy igneous rocks, the relics of whose activity have aided in making up the

Preliminary Report on the Mining Industries of the Telluride Quad- rangle," U, 8, O. S,, ISth Annual Bepart, Part III., p. 761. t Op. ciL,p, 768.

The Camp Bird Mine, Oitrat, Colorado. 503

immense areas of rock which erosion, far-reaching and long-continued, has now ex- posed to view. In the San Juan region particularly, flows of volcanic lava are strongly developed, while dikes and sheets of rock of dioritic type have been in- truded into and are intercalated with the sedimentary beds, and deep-seated maatifi or laccoliths of diorite have deformed and rent the clastic beds with which they are associated. The San Juan mountains owe their origin and present elevation to the igneous agencies referred to above.*'

In the mountains surrounding Imogene basin (Fig. 3), and in the cliffi bordering the canon below, the relations which the sedi- ments bear to the overlying volcanics are illustrated typically and graphically on a stupendous scale.

Since the horizon of the sedimentary beds is at least 2000 ft. vertically below the present workings of the Camp Bird mine, this paper has little concern with them. Mr. Whitman Cross has most thoroughly studied the geology of the San Juan, and the reader is referred to his many able publications in the re- ports of the United States Geological Survey and elsewhere for detailed information along this line.*

The Ouray limestones exposed in the vicinity of Ouray are of Devonian age, and have an exposed thickness of 200 ft. in Canon creek.

Overlying the Ouray limestone, forming cliffs with nearly vertical escarpments above the town of Ouray, lies the Her- mosa formation of the Upper Carboniferous, which consists of alternating limestones, grits and sandstones, with a prevailing reddish color. The Dolores red-beds, conglomerates, sandy and shaly layers of the Triassic formation, overlie the Her- mosa beds. The representatives of these two formations are not easy to distinguish without special examination, but, accord- ing to Messrs. Cross and Ransorae, the Hermosa series has the greater development in Canon creek. The total thickness of the two is not far from 2000 ft. These sediments, dipping gently to the west, are overlain directly by the unconformable Telluride conglomerate, which dips east. This conglomerate, easily recognized by the large and well-rounded included peb- bles, attains on the walls of CaSon creek a thickness of only 100 ft. The pebbles are of many kinds — granite, schist, quartzite, red sandstone and eruptive rocks. Occasionally

Especially to be consulted is the sketch of the geology of the Silverton Quadrangle, furnished by Mr. Whitman Gross, to accompany Mr. Bansome's monograph, BvU, U, S. G, S., 182, p. 30, et wq.

i04> THE CAMP BIRD MINE, CURAT, OOLORAPO.

they are over a foot in diameter. The formation becomes gradually thicker toward the west, attaining to nearly 1000 ft. in the Mt Wilson district of the Telluride quadrangle.* The rocks with which this paper has mostly to deal are the complex series of volcanic flows, tuffs and breccias which overlie con- formably the San Miguel formations.

The San Juan Breccias. — The first of them, in Imogene basin and the gorge of Canon creek below it, is the San Juan series of andesitic breccias. This formation, dipping slightly to the east, and having a thickness of something over 2000 ft., ap- pears in its lowest manifestation in the valley of Canon creek at an elevation of about 9600 ft. The contact between it and the overlying intermediate series of andesites lies at an eleva- tion in Imogene basin of approximately 11,750 ft. The series is recognized by its prevailing mottled appearance, with dull- red and green colors. It contains fragments, generally angu- lar, of different andesites in a tufaceous matrix. Its origin ia attributed by Mr. Cross partly to igneous agencies, while por- tions of its layers show a water-laid arrangement which implies the presence of lake- or stream-conditions during its forma- tion. This heavy series of breccias and ash-beds is the most extensively developed in the San Juan mountains, and at its horizon most of the present productive mines of the district are situated.

The Silverton Series, — This formation, which was formerly known as the Intermediate, f overlies the San Juan breccias. It is a comprehensive group of andesitic and rhyolitic flows and tuffs. It has a thickness in Imogene basin of about 1000 fb. rapidly thinning toward the west and thickening toward the east. Mr. Cross says that its lowest member in most places is a rhyolitic flow or flow-breccia of peculiar character. Its largest masses, however, are said to be lavas of rhyolitic base containing many inclusions of both rhyolite and andesite.J Andesitic flows with prevailing dark color are very character- istic of the Silverton series. The upper contact between this series and the overlying Potosi series of rhyolites is often

Geologic Atiaa of the United StateSj Telluride Folio, Cross and Purington U.S. (?. aS:,1899. t TeUuride Fdio, U. S, 0. S., 1899. t Buttetvn 182, U S. G. S., p. 32.

The Camp Bird Mine, Ouray, Colorado; 506;

marked topographically by well-defined benches in the upper parts of the basins.

The Potosi Rhyoliies, — Above these benches the rhyolite, ridges and peaks of the mountains, in the country about Imo gene and the surrounding basins, make precipitous escarpments. The rhyolite cliffs of Imogene basin are ornamented by impoB-, ing rows of columns from 50 to 150 ft. in height, due to structure of the glassy rhyolite, brought out by the intense weathering of these high altitudes. The effect of the various horizons of sedimentary and volcanic rocks on the fissuring and the ore-bearing veins of the district will be discussed later,

A large mass of monzonite-porphyry forms a prominent out-, crop on the north side of the wagon-road to Ouray, 2 milea below the Camp Bird mills.

The Camp Bird mine-workings exhibit, in both the upper and the lower levels, toward the west end, occurrences in the form of dikes which resemble rather the Silvertou type of andesite than the breccias. The horizon of the andesite-flows has apparently not been reached in the upper level of the mine, as the upper cross-cut is evidently in the breccias. These oc- currences, therefore, seem to be somewhat abnormal.

In the adit-level, No. 3, at a point in the west drift 100 ft. west of Wo. 10 chute, blackish andesite, comparatively free from fragments, appears, at intervals, in the hanging-wall for the en- tire 1000 ft. of this drift. Such contacts as are traceable be- tween this and the normal breccia appear to have an approxi- mately NE. direction.

In the No. 2 level, 300 ft. above, in the west drift, at a point 1760 ft. from the junction of the cross-cut with the vein, an inclusion of rhyolite, the diameter of which did not exceed the height of the drift, was found in the hanging-wall ; and for 300 ft. west of this point the dark andesite, characterized by con- choidal fracture, was continued, and was then suddenly cut off, the normal pink and green breccia taking its place. For 1000 ft. farther along the drift, dikes of the andesite appear at inter- vals in the walls.

In the extreme west end of the No. 1 level, above, the same rock, of dark color, but containing numerous fragments, has recently been found. In all other parts of No. 1 drift, and in the stopes above, the rock resembles the San Juan breccia.

506 Thb Camp Bird Mine, Ouray, Oolorado.

Judging from these occurrences, it is likely that there is, at the general level of the Camp Bird workings, a somewhat complicated mingling of the San Juan formation with this purer andesite. Perhaps it is allowable to suggest that here and farther to the west there exists a stock of the interm diate andesite, one of the sources of this upper series of lavas. The rhyolitic flow, mentioned above as the characteristic lower member of the Silverton series, was not identified in the mine* workings.

The Veins and Mssuring. — My views concerning the origin and nature of the fissure-systems in this portion of the Saa Juan country have been set forth at some length in a paper on the Telluride district* I have seen no reason to change the opinion that most of the ore-deposits of this region have been formed in pre-existing open fissures. A recent study of the mining district north of Silverton and east of Telluride lends strong confirmation to this opinion. The neighboring de- posits of Red Mountain, as Mr. Ransome has pointed out, ex- hibit what is very likely " a local modification of the general fissuring of the region."t

The Telluride quadrangle shows four prevalent directions of fissuring, along which the productive ore-bodies have been de- veloped. These systems are found to be approximately (1) E.-W., (2) NE.-SW., (3) KS., and (4) NW.-SE. The E.-W. system of fissures is the one exemplified in the Camp Bird ore- deposit. The vein has an average direction not far from N. 80° W., and, like the majority of the prominent veins of this im- mediate section, dips south. The dip varies within small limits in difterent portions of the workings, averaging 70° from the horizontal. The Camp Bird vein follows, in the main, two feets of fissures, one striking IT. 87° W., and one striking N. 72° W. Subordinate to these is a set striking K 51° W. The dip of all these systems is to the south. By reference to the Telluride bulletin it will be seen that the N. 87° set of fissures is prominent throughout the district to the east of Imogene basin, extending even as far as Mt. Wilson.. It is the direction taken by the Pandora vein, J prominent in the

♦ Op, cU., pp. 764, €L Beq. f BvU, 182, U, S. O. &, p. 108.

X Mr. Ransome concludes that the Camp Bird and the Pandora are probably the same lode.

Thk Camp Bird Minb, Ouray, Colorado. 507

workings of the Smuggler-XJnion mine, and it is also the direc- tion of several prominent veins in Bear creek to the southeast of Telluride. A strong fissure-zone bearing this direction was also noted in the Virginius basin. The N. 61° W. direction which the Camp Bird vein occasionally assumes corresponds to one of the prominent directions of the Tomboy vein, which is not far away,*

I think that the fissures of the San Juan mountains are separated by alternating narrow and wide intervals ; that, in a ven system, these alternations occur in more or less rhyth- mical sequence ; that wide belts of crushed material have re- sulted from the intersections at narrow angles of the narrowly separated zones, representing separate systems of fissures ; and, finally, that the position of the larger ore-deposits of the dis- trict was determined by the situation of such intersections, — it being adopted as a necessary hypothesis that the present veins represent filled fissure-zones. The Camp Bird vein has -evidently been formed by the intersection of three closely spaced zones on the three sets of fissures above specified, its direction being mainly determined by the first two. To this fact it owes its remarkable width. Illustrations of the feature mentioned in connection with the Tomboy vein, namely, that of the ore following its previous direction for a distance in one direction after its switching to another, are frequent and well-marked. At chute No. 10, level 3, on the vein turning to N. 87° W. from N. 72° W., a number of small stringers continue in the first direction. In the east end of No. 3 level a set of joints, car- rying more or less ore, strike N. 51° W., and continue into the hanging-wall after the vein takes a N. 72° W. direction.

Occasionally it is difficult to tell in which direction to drift at the intersection of two sets of fissures, as at No. 6 chute in the east drift, 3d level, where a false lead was followed for 200 ft., N. 87° W., after the main lead had switched to N. 72° W. Even in close proximity to the andesitic mass which is referred to below, where there was a tightening and practical oblitera- tion of the fissures for over 500 ft., the western continuation of the lead afiTords illustration of the constancy of the fissuring tendencies along definite lines.

Telluride Report, U. S. O.8., p. 778.

508 The Camp Bird Mine, Ouray, Colorado.

The Camp Bird is an illustration of the larger type of vein. Its average width, from 6 to 7 ft., is somewhat greater tlian that of the San Juan veins in general, which are characterized rather by permanency in longitudinal and vertical dimensions. Smooth walls are not a feature of the Camp Bird deposit, a well-defined flat surface on either foot- or hanging-wall being the exception. Slickensides, striations, groovings or caruncu- lated surfaces have not been observed. The presence of finely- comminuted and re-cemented fragments of the vein-matter, re- ferred to below, may indicate that relative motion of one wall on the other has at some former period taken place ; but there is no evidence of recent motion of such a character.

With perhaps one or two insignificant exceptions, there is no- indication of faulting subsequent to the formation of the ore. Near No. 11 chute, in the west end of the lower level, a normal fault was seen ; the south side of a small stringer having moved down about 3 inches. Other such cases have been observed ; but the throw was always small. On the No. 2 level, 1750 ft. west of the cross-cut, there is a local pinch of the vein, which does not appear either in the lower or the upper level, and which there is no evidence to connect with any faulting of the vein. On No. 2 level the pinch was nearly coincident with the body of dark andesitc already described. This rock was harder than the normal country- rock, and broke with a conchoidal fracture. As the vein retained its normal width both above and beloWy it may be suggested that the andesitic magma here crystallized into a hard and dense bleb, rendering any widening of the first fissure difficult. After passing through the area of andesite and mingled andesite breccias described above, a distance of nearly 900 ft., the vein resumed its normal width.

It has not been found that the width of the veins of thi& region suflfers, as a general rule, any consistent change as they pass from the San Juan series into the intermediate andesites, or vice versd. Both these formations gave way to the fissuring forces with practically the same facility. In the Potosi rhyo- lites, however (the rocks now appearing on the tops of the mountains), the vein's are generally small, and sometimes diffi- cult to trace. The rhyolite is often referred to as " cap-rock,'* and the veins are said to be " cut oft'" on entering it; but this expression is misleading, since, in every case that has come

The Camp Bird Mine, Ouray, Colorado. 509

under observation, the fissuring is continued, though with much smaller manifested results, through the rhyolite to the tops of the mountains.*

The Vem-FiUing. — The Camp Bird vein does not offer a great variety, either of gangue-minerals or metallic sulphides. Of the values, which consist of gold, silver and lead, 96 per cent, are gold. This occurs both free in quartz and combined me- chanically with other metallic minerals. Unmistakable evi- dence of the presence of tellurium has been found in tests on the richer portions of the ore. The lead occurs as galena, which contains also all the silver, outside of that which is neces- sarily associated with the gold. Silver sulphides and sulph- arsenites, generally present in the upper portions of neighbor- ing San Juan veins, are, so far as known, entirely lacking here.

The principal gangue-mineral is white, opaque, generally crystalline quartz. White, massive quartz is found on the edges of the main vein, interlaminated with country-rock, and often sprinkled with crystals of pyrite and galena, and flakes of chalcopyrite. . Within the vein, the quartz which is richest in gold has a dull luster, and consists of closely-packed crystals, often showing spherical aggregates, in which the pyramidal terminations of the ore at the center of the sphere and the striations characteristic of the prism-faces of this mineral are very strongly marked upon the radiating crystals, as if there had been breaks in the continuity of crystallization from aque- ous solutions. A typical example of rich Camp Bird ore is described by Mr. Eansome (p. 89, Bull. 182), and is reproduced in an accompanying drawing in a remarkably beautiful and graphic manner. The centers of these spheres, which are com- monly 8 in. in diameter, are frequently occupied by more or less impure rhodonite.

Open cavities are also very frequent, varying from almost microscopic size to a diameter of 10 ft. A remarkable one, found in a stope at the west end of No. 3 level, was 10 flb. across, 12 ft. high, and lined with quartz crystals, together with a crystalline mass of calcite, and possibly some siderite, the

Mr. Bansome has arrived at concluaions somevrhat different from mine regard- ing the nature of the fiflsoring in the area ander consideration. BvlL 182, (7. O./&,p.208.

510 The Camp Bird Minb, Ouray, Colorado.

whole being coated with oxides of iron and manganese. Quartz crystals 5 in. in length are sometimes found in these cavities.

Calcite occurs throughout the ore, though never in large quantity. In vugs in the stope near the east end of No. 3 level were found beautiful masses of pink crystals of " dog- tooth " spar.

Rhodonite, remarkable for its color and its curious associa- tion with the quartz and metallic minerals, occurs abundantly — never in large masses, but generally in lamellse from 1 in. down to microscopic width. Fig. 4 represents a typical occurrence of the rhodonite, quartz and calcite, with their relations to the metallic minerals. Fluorite is mentioned by Mr. Ransome.

Chlorite, usually associated with good values, is present to a small extent.

Of the metallic sulphides, the principal is normal pyrite, either finely crystalline or massive, and either associated with quartz and rhodonite, or impregnating the bands of country- rock included in the vein or constituting the walls. It cannot in general be said to play an important part as a matrix for the gold, since, as is shown by Messrs. Woods and Doveton in the succeeding portions of this paper, an interesting feature is the increase in the amount of pyritic impregnation which the wall- rock undergoes in passing from west to east. Whether it car- ries a corresponding increase in gold-values has not been fully determined.

Zinc-blende is very rarely seen in the ore ; but the presence of zinc is proved by the analyses given in the following part of this paper.*

Magnetite, a somewhat unusual constituent of gold- and silver-veins, has been shown by laboratory tests to be present in considerable quantity in the Camp Bird, although it cannot be recognized by the inspection of hand-specimens of the ore. It occurs intimately mixed with galena in the white quartz which is commonly free from other metallic minerals except gold. The mixture of galena and magnetite produces in the quartz wavy lines, or indistinct cloudy bands, which are an almost in-

Mr. BanBome mentions its occurrence in connection with the dark hands ao- -coiiipanjing the rich ore.

The Camp Bird Mine, Ourat, Colorado. 511

fallible indication of accompanying high gold-values. The exceeding fineness of the particles of these minerals makes it impossible to distinguish either the galena or the magnetite by their physical characters. Fig. 4 illustrates a common occur- rence of this mixture in bands in connection with the parallel bands of rhodonite and the accompanying finely crystalline quartz. This structure is not unlike the California vein-ma* terial ordinarily referred to as " ribbon-rock."

Of the ore-minerals, properly so-called, galena, containing silver as well as lead, is the most conspicuous. As already noted, it is associated with magnetite in a peculiar manner. Most of it, however, occurs in bands from 1 to 4 in. wide, and crystallized with a fair degree of coarseness in solid masses, which generally follow with regularity, for considerable dis- tances, one or the other of the walls. Galena also occurs, sprinkled in the white quartz with streaks of rhodonite.

Chalcopyrite occurs, according to its habit in the veins of the San Juan, in irregular spots and blotches through the vein. If there be any special peculiarity in its occurrence here, it is that it appears to be associated rather with the in- cluded portions of the country-rock than with the quartz. As will be seen in the chapter on milling operations, which follows, the amount of chalcopyrite must be small, since the percentage of copper in the ore is insignificant.

Arsenic has been recognized in traces by Mr. W. F. Harris in the assay-ofiice, but no compounds of this metal have ever been seen in the ore.*

Gold and Silver. — As already observed, the gold of the Camp Bird vein is associated with mixtures of galena and magnetite, and to a less extent with pyrite. Pure white quartz, with na visible metallic minerals, is found to contain good values in gold. The gold occurs finely divided, and is rarely seen in the ore. Its fineness is .740, the chief impurity being silver.

The silver occurs with galena, and as an alloy with the gold. It is possible that silver sulphides and sulph-arsenites occur in the ore, but hitherto they have not been found.

I am indebted to Mr. G. W. Pickaid, of Boston, for much assistance in the mineralogical and chemical determinations.

512 The Camp Bird Minb, Ouray, Colorado.

Secondary JSfiwerafe.— Under this term are included the prod- ucts of decomposition, induced, for the most part, by the per- colation of surface-waters. They are few, and oflTer no features of special interest Limonite, due to the decomposition of pyrite, is found in the more weathered parts of the vein, and lead and iron carbonates are also present in small quantity. Wad and the other oxides of manganese are found to a limited extent, mostly as coatings on the ore. A substance resembling kaolinite, perfectly white and pure, with a soapy feel, was found near the center of the vein, in the stope over No. 8 chute, in the Blue Bird level.

The deposit here described is of the normal fiUed-fissure type. Countless examples may be seen, in the mine-workings, of perfectly angular fragments of country-rock included in the vein-matter. Yet certain features which it possesses have caused the writer to question whether " spaces of dissolution do not exist. The large cavity or chamber once referred to (shown in Fig. 5) appears, from the section shown (a drawing from a face exposed by recent shots in the stope), to have been cut out of a previously-formed portion of the vein. The walls of the cavity were as rounded as those formed in lime- stone by percolating waters, and the bottom was occupied by 2 ft. of bluish and white clayey material, arranged in layers, and containing fragments of quartz-combs and separate crys- tals.

It is assumed that the original deposition of the ores in me- chanically formed fissures was through the agency of heated waters. It is not pertinent to the discussion of the case in point whether these waters were of meteoric or of deep-seated origin. Granting that they entered the open fissures penetrat- ing the plutonic, volcanic and sedimentary rocks of the region at a conceivably moderate depth,t still they were charged with the minerals in solution necessary for the formation of the ore and gangue minerals of the future veins. The waters, contain- ing alkaline carbonates, were solvents for all the metals, earths and SiOa encountered in their passage through the rock-mass, but not, to any extent, at the earth's surface ; this took place

Posepny's term.

t Lindgren, " Qold-Quartz Veins of Nevada City and Grass Valley," Ann. Bept. U. S. GeoL Survey, 1895-96, Part II., page 176.

The Camp Bird Mink, Ouray, Colorado. 613

under extraordinary conditions of heat and pressure which, it is generally conceded, must exist at the deep-lying vein- forming horizon. The solution finally entered the fissures in part as sulphides, and partly as alkaline carbonates partially charged with sulphides.

Moreover, such circulating waters were in large, rather than small quantities. Conceive a portion of an open fissure, situated at the deep region,* into which water (which has traversed, by capillary action, the interstices of a rock-mass of unknown lateral and vertical dimensions) finds entrance. This water will, as Posepnyt states, mount in the open channel, cooling and depositing its mineral load during the ascent.

It is admissible that the whole of the fissure may not be filled by the material precipitated from the water passing through it at a certain period ; that at periods, separated from one another by no great time intervals, pulses of heated water may find access to and ascend in the fissure successively; and that pauses may occur in the circulation, allowing, temporarily, the still conditions which Mr. RansomeJ suggests. It is also conceivable that varying conditions may obtain in difterent portions of the rock-mass which contributes its mineral load to the waters. Thus at one period the water may enter the fissure with more power to dissolve ; at another period, with more ability to precipitate or leave its load, which is already in solution.

It is therefore proposed, in explanation of the occurrence illustrated by Fig. 4, that the space or vug may have been dis- solved out of the normally formed vein at a period shortly after the original deposition of the ore ; and that the agent respon- sible for this solutive action was water, whose solvent powers for SiOj and metallic sulphides were not wholly exhausted at the period of its migration from the capillary interstices of the rock-mass to the comparatively open space offered by the fissure.

That the passage of water through rocka is of a capillary nature is interest- ingly illustrated hy the researches of sanitary engineers. For example, Mr. John Thresh {Water and Water-Supplies, Phila., 1901, p. 351) says, that even in fis- sured strata, water collected from deep wells is remarkahly free from bacteria, these haying been removed from the water in its passage downward, by the rock acting as a capillary filter.

t Posepny, The Qenene of OrerDeponte, 1892, p. 24 ; 2d ed., 1901, p. 27.

t BuUetin 182, U, S, Q. S., p. 136.

514 Thb Camp Bird Mine, Ourat, Colorado.

Such water, in ascending, would first part with the silica and some of the silicates. The deposit of clay-like material found in the bottom of this cavity, in stratified arrangement, may have resulted either soon after the cavity was formed or at a period considerably later. It is likely that this material con- sists largely of kaolinite and sericite. Quartz crystals, small and well formed, are found in it.

There is considerable evidence in different portions of the deposit of a re-arrangement and re-cementing, by secondary silica and by calcite, of the original constituents of the vein. It is not easy to see, however, what agencies could have been at work to produce by dissolution, in material commonly regarded as insoluble, under conditions which obtain at or near the earth's surface, cavities of such size as the one cited. If the occurrence has any bearing on the question of secondary changes and arrangement in ore-deposits, it seems to indicate that such changes as occurred in this particular deposit took place far below the earth's surface. In other words, that this re-arrangement of the ore is not a surface-phenomenon, but a concomitant or approximately immediate result of the condi- tions controlling the original deposition of the ore.

Origin of the Ore. — am not at present prepared to enter into this subject with regard to the Camp Bird vein. I have found nothing in the course of my examination to justify a conclusion as to the source of the ore different from that already expressed in the Telluride Bulletin.* Certain features of this deposit, notably the different character of its ore and values from many of the veins in the neighboring portion of the Telluride quad- rangle, render it possible that a full investigation of the sur- rounding conditions would throw further light on the age of this deposit, with reference to those about it. Unfortunately, such an investigation was not possible before the preparation of this paper.

A somewhat remarkable occurrence may be mentioned at this point, which was brought to the writer's attention by Mr. Laurence Cronin, the mine-superintendent. It was a jagged and angular inclusion in the vein (in the stope over No. 4 chute in No. 3 level), about 12 in. long and 6 in. broad, and consist-

Op, eU.y p. 824.

The Camp Bird Mine, Ouray, Colorado.

ing of a mixture of very finely crystalline and amorphous silica, of laminated structure and slightly pinkish tinge. Closely examined, it was seen to contain very small druses lined with quartz crystals. Hydrochloric acid causes efterves- cence in all parts of the specimens taken. Two other similar but smaller inclusions were observed in the center of the vein (here 6 ft. wide), near the one described. In the largest mass,

Fio. 2.

Looking up Cafion Creek from below Imogene Basin.

the laminations were nearly at right angles to the dip of the vein.

These inclusions had, in fact, all the appearance of fragments of silicified sedimentary rock ; and their position at this hori- zon seems almost inexplicable. An analogous occurrence was, however, found, several months ago, by Mr. Arthur Collins, manager of the Smuggler-Union property, in the upper work- ings of that mine, and consequently at a horizon fully as high as in this case. That was even more remarkable; since the

616 The Camp Bird Mine, Ouray, Colorado.

Fio. 3.

Imogene Basin, looking south.

THE CAMP BIRD MINE, OURAY, COLORADO. Fig. 4.

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Portion of yoin in East drift, Level No. 3, showing Mineral association.

Fig. 5.

Thb Camp Bird Mine, Ouray, Colorado.

Fio. 6.

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The MacDouough Stamp-Guide.

The Camp Bird Mine, Ouray, Colorado. 519

Fig. 7.

Mill Water-Power ; summer conditions.

520 The Camp Bird Mine, Ouray, Colorado.

. Fig. 8.

Dam Built to Form Reservoir for Collecting Slimes.

Fig. 9.

Camp Bird Mills.

The Camp Bird Mine, Ouray, Colorado. 521

inclusions, though smaller, were, to all appearance, metamor- phosed limestone, containing what appeared to be fossil crinoid stems. Mr. Collins kindly allowed me to examine the speci- mens shortly' after their discovery.

The writer is unwilling to adopt, without further evidence, the opinion that these fragments have been brought up from below. Yet from what nearer source they could have been <lerived it is impossible to see. It is hoped that this point will be discussed by members who have observed similar phe- nomena.

FiQ. 10.

Camp Bird Mills. Looking down Cafion.

The Vqin in Depth, — Judging from experience in working neighboring veins, it appears likely that the Camp Bird will continue in depth with undiminished width to approximately 2000 ft. below the present level of the lowest workings. Nor there reason to expect that its values will decrease within this distance. The San Juan ore-deposits are exceedingly young, geologically ; and, to put it briefly, it is the fops, and not the stumps, of veins which are now exposed to view. The mine under consideration lies in the upper portion of the heavy 'Sin Juan formation, which is known to have a thickness of at least 2000 ft. in this district. General experience here has j*liown no impoverishment of the veins which carry the bulk of their values in gold, in passing from the upper to the lower

522 The Gamp Bird Mine, Ourat, Colorado.

portions of this formation. In the case of many of the silver- bearing veins, the rich sulphides and sulpharsenites of silver found at the upper levels have not continued in depth. On the other hand, cases have occurred where values have increased with depth.

The influence of the country-rock on the width of veins in this district is well known. In the underlying sediments, de- posits as valuable as those found in the breccias are not likely In the San Miguel conglomerate, veins operated in the Telluride and Silverton districts have been proved fairly valuable. The thickness of this rock, however, where it underlies Imogene basin, must be less than 100 ft. ; and therefore its influence on the vein has no great importance.

In the Carboniferous and underlying sediments in the vicinity of Ouray, deposits of the precious metals have been worked at a profit for several years. It may not, therefore, be assumed that the values in the Camp Bird vein will not continue through the Triassic beds. Should the mine be worked to the depth of the underlying limestones, there is a possibility that heavy bedded sulphide-deposits will be encountered along the line of the vein.

Occurrence of the Ore in the Vein. — As in most typical fissure- veins, shoots of ore occur in the Camp Bird deposit. Hitherto,, however, these shoots have not been found to have a definite pitch in the plane of the vein ; at least, very little correspond- ence appears to exist in the directions taken by their boun- daries. Shoots have been worked continuously in the mine from the surface to the depth of 800 ft, which is that of the lowest present workings ; and there is no indication that they do not continue farther down. Since they vary in horizontal length, it seems fair to assume that the greatest dimension i& measured on the dip of the vein.

This portion of the San Juan region is not characterized by a definite arrangement of the ore in the veins. In some indi- vidual cases a succession of shoots has been found ; but there is no agreement in this regard between one vein and another. For example, Mr. Arthur Winslow* mentions the fact that in the Liberty Bell mine, near Telluride, the results of sampling

Trans.y xxix., 296.

The Camp Bird Minb, Oukat, Colorado. 523

proved that the vein, so far as developed, was practically one shoot of low-grade ore 2000 ft. in length. This occurrence is not to be correlated with the neighboring veins in Marshall basin, nor do those veins among themselves present any uni- form arrangement of ore.

The development of the Camp Bird vein has not afforded, thus far, evidence of local secondary enrichment or impoverish- ment. The secondary enrichment of veins, recently the sub- ject of no little discussion, has been lately studied in the San Juan region by Mr. Ransome, who concludes that the phe- nomenon has there a limited manifestation. If , as I under- stand from the paper by Mr. Walter Harvey Weed on " The Enrichment of Gold and Silver Veins,"* such enrichment below the " iron hat " depends on the presence of a large amount of pyrite in the ore, it would scarcely be expected that the phenomenon would play a great part in the veins of the San Juan in general. If it has any manifestation in the dis- trict, observations thus &r seem to indicate that those veins carrying silver values in excess of gold have been the ones subject to it In the Camp Bird vein, the uniformity of values hitherto encountered in going from higher to lower levels seems to preclude the belief that there has been a transfer of values from one horizon of the deposit to another.

Development. — The main cross-cut, 2200 ft. long, at level No. S, runs south to cut the vein. The two upper levels, also, are opened by cross-cuts. The total length of development-work, including cross-cuts, drifts on the vein, stopes, raises, mill- holes, shafts and winzes, is between 5 and miles. In the west end of the workings, over 1500 ft. of depth beneath the top of of the mountain has been gained.

The main cross-cut at No. 3 level is 7 by 7 ft. in the clear, and timbered for the first 420 ft from the entrance (that is, so long as the tunnel is in the " slide-rock ") with square sets (posts and caps 12 in. square). After entering the solid rock, no timbering is required. The upper cross-cuts, also, are timbered only in the slide-rock. In general, it may be said that, throughout the mine-workings, timbering is required only in the chutes or mill-holes, raises, winzes, and the floors of stopes.

Trans., xxi., 424. VOL. . — 32

524 The Gamp Bird Mine, Ourat, Colorado.

The ground in the mine stands remarkably well, several stopes from 10 to 20 ft. wide having required no timbering.

The main cross-cut is lighted with incandescent lights 100 ft. apart In the No. 2 and No. 8 levels and cross-cuts, the 30-lb. steel-rail track is 22 in. wide. Compressed air is conducted into the main cross-cut by a 6-in. pipe, the size of which is successively cut down as the air passes through the different workings to various parts of the mine. A 2- by 1-ft. ditch for water is cut in the lower cross-cut; and there are smaller ditches in the levels.

From the upper level, and stopes above, the ore is handled entirely by gravity, through chutes, to the lower level, then trammed by mules to the ore-bins at the mouth of the main adit, and dropped into the tram-buckets, which run by gravity over the aerial tram-line, 9000 ft. long, to the mill. From all other parts of the mine the ore is similarly handled. No ore is trammed out to the surface at the No. 2 or No. 3 levels. From the lower level, 9 end-dumping cars, of a little over 1 ton capacity each, are run in a train. The installation of electric tramming is now under consideration. The average quantity of ore trammed out is a little over 200 tons per day. Shafts are now being sunk on the vein from the lower level, and one of these is already 200 ft. deep. Part of the tonnage making up the daily mill-run is taken from this shaft.

In chutes and raises, stulling with 5-ft centers is used. Mill- holes are put in at intervals of 60 ft. ; and, as oft;en as neces- sary for getting the ore from the upper levels, these are con- tinued upward as raises. Every alternate chute is supple- mented with a man-way and slide for steel.

In stoping, it has been the custom to stuU and lag over the top of the drift, forming a floor for the power-drills. Recently there has been put in practice, where ground is suflEiciently solid to warrant it, a system introduced by Mr. Cronin, the mine-superintendent. When a new stope is to be started, a raise is put up from 6 to 10 ft., according to the solidity of the ground, and timbered as usual. From the top, the vein is run on as if a drift were being started. The machine-men thus stand on a solid block of ore in place, instead of stulls and lagging. The pillar thus formed is lengthened as far as it is desired to carry the stope, say 50 ft., to the place of the next

Thb Camp Bird Mine, Ourat, Colorado. 525

chute, and the broken ore falls on the solid pillar, the timber- ing being thus practically replaced. The pillar is, of course, always accessible as ore, when its extraction is desired.

The mine is at present well off for timber, the lower level being situated below timber-line, and there being a fairly heavy growth of spruce on the side of the mountain near by. Spruce timber is plenty along the mountain sides from the mine-work- ings to the mill.

It is the practice in all the mining operations to take out only about 40 per cent, of the ore broken in stoping, allowing the rest to remain in the mine. It is found that this 60 per oent. of broken ore very nearly fills the space occupied by the total original ore in place. An advantage of this system is that there is no necessity for going into the walls for waste to fill the stopes, since these are continually filled with broken ore. For the most part, levels, raises, chutes and winzes have been run in ore; and at present the percentage of waste trammed out is very small.

Cross-cuts and main levels are carried 7 ft. above the track, with a grade of 4 in. to 100 ft.

All drifting and breaking is done by machine-drills, operated by compressed air* from the compressor-plant at the mouth of the main cross-cut. This consists of two 75-H.P. cross-com- pound compressors, with air-cylinders of 19- and 12-in. diam. respectively, and 16-in. stroke; and one 200-H.P. compressor (2-stage type), driven by a cross-compound Corliss engine. This has air-cylinders of 22-in. and 18-in. diam., and 36-in. stroke. At present, 19 machine-drills are used in the mine, the size most in favor having 3J-in. cylinder. More of these will soon be installed. Hercules powder of 40 per cent, strength is used. Holes are fired just before 4 o'clock, leaving 8 hours for the mine to clear of smoke. The two 8-hour shifts go on at 7 o'clock, night and morning. Natural ventilation, supple- mented by that supplied by the air from the drills, affords ex- ceedingly good air in nearly all parts of the workings.

Electrical power for the compressors is furnished by the Telluride Power Transmission Co., from the line which comes over the mountains from the Ophir Loop station (a distance

The writer is indebted to Mr. William Scheele, the master mechanic, for data conoeniing the oompressed-air plant.

526 The Gamp Bird Minb, Ourat, Colorado.

along the line of 21 miles), which carries 10,000 volts of 8- phase alternating current, and " steps down " at the mine trans- former-house to a voltage of 400. The upper floor of the com- pressor-house carries the three Westinghouse 3-phase induction- motors : two of 100-H.P. each, and one of 200-H.P., which are connected severally by pulleys with the three compressors. '

A supplementary steam-plant is provided in the compressor- house, by which the compressors can be run, if necessary.

Labor, — About 200 men are now employed in and about the mine, the day-shift comprising 180, and the night-shift 70* There are very few outside men. Wages are as follows, per day:

Large-machine men, $4.50

Large-machine helpers, 4.00

SmaU-machine men, 4.00

Blacksmiths, 4.00

Blacksmiths' helpers, 3.25

Timbermen, 4.00-4.50

Timbermen's helpers, 3.00

Shovellers, 3.00

Tramway men, 3.50

Trammers, 3.00

Engineers, 4.50

A large boarding-house at the mouth of the lower cross-cut, lighted by electricity, heated by steam, provided with baths, and supplied in all parts with running-water, under 80 lbs. pres- sure, provides comfortable lodgings for $1 a day. Much atten- tion is given to maintaining proper sanitary conditions.

Tram, — The Bleichert aerial wire-rope gravity-tram, which transports the ore from the tram-bins to the mill, has been in op- eration without breakage of any sort for over three years. The entire length is slightly over 9000 ft., — the vertical distance between the two terminal stations being 1350 ft. The tram- line is in two sections, the angle-station being at about two- fifths the distance from the upper station to the mill. Tension- boxes are provided at both the angle-station and the mill-station. This line was constructed, including all towers, in the short space of 48 days. More than 200,000 tons of ore have already been transported on it. All supplies for the mine are trans- ported over the tram, the weight of the loaded ore-buckets sup- plying the power.

The Camp Bird Mine, Ouray, Colorado. 527

Water. — The quantity of water encountered in the Camp Bird mine-workings is variable. In winter, as might be ex- pected in a region where frost penetrates the ground to such an extent, the amount of water is much smaller than in sum- mer. The three levels are drained separately ; and in Jan- uary, 1902, less than 100 gals, a minute was issuing from the lower cross-cut, while a proportionately smaller amount came from the No. 2 and No. 1 levels. In summer, on the other hand, it is said that as much as 2500 gals, per minute some- times flows out.

As an example of the winter-conditions, the shaft now being sunk from the lower level on the vein makes only 1500 gals, of water in 24 hours, or but little over 1 gal. per minute.

A few words concerning the level at which ground-water is encountered may be appropriate. Where the ground remains frozen to a considerable depth during six months of the year, as may be said to be the case here, the decomposing influences of the atmosphere are much retarded. Outcrops of veins, therefore, frequently present perfectly fresh metallic sulphides. Consequently, the presence of unoxidized sulphides cannot be, as in a flat country, a criterion for determining the level of the ground-water. This level, if it may be so-called in this rugged region, doubtless has the form of a plane more or less con- formable with the configuration of the overlying topography, and lying at a considerable distance beneath the surface. It is not possible to believe that anything but surface-waters have been encountered as yet in the workings of the Camp Bird ; and in the surrounding district, where a similarly variable quantity of water is encountered, it is extremely likely that all is surface- water. That there is a considerable amount of ground-water in this region, however, can hardly be doubted, in view of the evidence furnished by the mine-workings at lower altitudes. Mr. H, C. Lay* has recently made some valuable observations in regard to this point.

So far as the writer has observed in this portion of Colorado, the greater the depth to which mines have been worked, the more water has been encountered. Since, in some cases, from 2500 to 8000 ft. of depth below the surface has been reached

''Recent Geological Phenomena in the Telluiide Quadrangle," etc., 2Va9u., zzxi., 558.

528 The Camp Bird Mine, Ourat, Colorado.

without getting below the level of the present valleys, it i& reasonable to suppose that, when further sinking is undertaken water will be encountered in even greater amount. The ob- served facts here are hardly in accordance with those noted in connection with the examples of deep mines, cited by Prof. J. F. Kemp,* in which little water is encountered.

Postscript.

(January 25, 1903.)

The. writers are indebted to The Camp Bird, Limited through the courtesy of Mr. John Hays Hammond, Consulting Engineer for the Company, for the following data concerning the history and product of the Camp Bird mine from October 81, 1896, to January 1, 1908. Mr. A. Chester Beatty, who kindly transmitted the data at Mr. Hammond's request, states that the records for the month of December, 1902, were not available, and, in consequence, an estimate was necessary in order to bring the total production up to January 1, 1908 :

Total tons milled and smelted, 195,461

Total gross value recovered, $6,530,430.00

Gross value recovered, per ton, . . 33.41

Profits, 4,316,798.00

Expended on construction and purchase of properties, . 696, 000. 00

The Camp Bird was transferred from Thomas F. Walsh to its present owners. The Camp Bird, Limited (an English com- pany). May 12, 1902.

The Camp Bird Mill. By Thomas H. Woods and Godfrey D. Doveton.

The output of the Camp Bird mine may be considered ideal milling-ore, yielding its values readily to amalgamation, vanner- concentration, and subsequent cyanide treatment of the tailings. The method of treatment, while it offers few new features, is of interest as an example of the reduction of a docile ore. The following is a synopsis of the method employed : (1) Breaking

"The R61e of the Igneous Bocks in the Formation of Veins,'' Trans, , zxxi., p. 169, and Oenms of OreDeponts, p. 681.

The Camp Bird Mine, Ouray, Colorado. 529

with Blake crushers, (2) pulverizing with stamps, (8) copper- plate amalgamation, (4) vanner-conceutration, and (5) the direct treatment of the tailings by cyanide.

The Breaking of the (h*e. — The loaded tram-buckets, after leav- ing the tramway-terminals, are trammed on suspended tracks to the crusher-house and dumped on sets of grizzlies. Each ore-bin, of which there are three, is equipped with a grizzly at each end, the fines passing directly through the bars to the main bins, while the coarse falls to the crusher-jaws, and thence to the ore-bins. The grizzlies, 12 ft. long, set at an angle of 45°, pass all material under 2 in. The rock-breakers, Blake pattern, 9 by 15 in., set at 2 in., are placed directly under the center of the ore-bin. This arrangement insures a comparatively good mixture of the fine and the coarse rock.

Ore-Bins. — Each of the bins ha a capacity of one hundred and eighty tons. The floors are set at an angle of and lined with in. boiler-iron. The chutes, from the bins to the automatic feeders, are controlled by a rack-and-pinion gate. In addition to these ore-bins there is a large reserve storage con- taining sufficient ore to run the mill for six days.

The Stamp-Battery — Foundations. — Trenches, 10 ft. in depth, are blasted out of the solid rock, and the mudsills placed in the bottom are securely wedged against the sides of the pit, and then packed with concrete. Upon these the mortar-blocks, of 2-in. plank set on end, are spiked and bolted together. Two sets of binders, front and back, are bolted to the mortar-block, but not to the battery-timbers. The writers are of opinion that less jar is transmitted to the battery-timbers when they are not bolted to the mortar-blocks, because then they do not get the jar due to the impact of the stamps.

The mortar rests upon a rubber-gasket, in. thick, and is bolted to the mortar-block with 4 anchor-bolts, front and back. The battery-frame timbers are made of the best grade of dressed Oregon fir. The king-posts are bolted to the street-sills with 1 J- in. bolts of Norway iron. All bolts in the framing are of Norway iron, since cast-iron is of little use when subjected to such vibra- tion. The king-post is also bolted to the ore-bin above and below the cam-shaft floor. The mortars are of the Homestake pattern, but amalgamation is not conducted inside. It has been found advantageous here to use the battery as a pulverizing

580 The Gamp Bird Mine, Ourat, Colorado.

machine only, for a very perfect amalgamation is secured on the apron-plates.

The cam-shafts are of hammered steel, 6 in. in diameter and 14 ft. long, fitted with Blanton cams. Both steel and cast-iron cams are used, but steel cams have given the most satisfaction.

Babbitted journal-boxes are still in use, although two cam- shafts are running in bearings without babbitt. In the writers' experience, however, babbitted boxes are to be recommended, for the following reasons :

(1) The alignment of the shaft can be more easily kept true with a babbitted bearing, because, no matter how careftiUy the battery foundations are erected, a small amount of settling is sure to take place. This increases the difficulty of shimming up a cam-shaft bearing or a battery-post.

(2) In replacing a broken shaft with a new one, more perfect bearings can be obtained. Bearings without babbitt have a tendency to wear to a greater or less extent.

During the last four years, with an average of 46 stamps per shaft, four cam-shafts have been broken. This remarkably clean record is due in great part to the excellency of the bat- tery foundations. Extra cam-shafts are, however, always kept on hand ready for use.

The Stamps. — The stamps weigh 850 lbs. each, and drop 100 times per minute. The speed has recently been changed from 90, with the result that the capacity has been greatly in- creased, a better splash obtained, and a consequent reduction in slimes observed. The order of drop is 1, 4, 2, 5, 3. The drop is set at 6 in., and, as the shoes and dies wear, re-set at 8.

The even distribution of the weight in stamps is a matter frequently overlooked by machinery-manufacturers, too much weight being often apportioned to the stem and boss, with a tappet too light for the work it has to do.

The stems are made of soft steel, 14 ft. in length and 3J in. in diameter, and weigh 380 lbs. When broken at both ends they are sent to the machine-shop, thoroughly annealed, turned in a lathe, and again put into service. The tappets weigh 80 lbs., and are made of both cast-iron and steel. The latter is much preferred ; the steel tappets rarely break, have a much longer life, and seldom require facing.

The automatic feeders are mostly of the Challenge type, but

The Camp Bird Mine, Ouray, Colorado. 581

four are of the suspended type. The latter are much pre- ferred, as they take up but little space, and allow free move- ment around the mortars. The feed-tappets are attached to the middle stamp-stem. Solid feed-collars have been in use until recently, but are now replaced by a sectional feed-collar. By its adoption a great deal of time is saved in replacing a broken feed-stem, as no chipping of the broken stem is re- quired. The bosses are of cast-iron, weigh 250 lbs., and are attached to the stem in the usual manner. The plugs are re- moved with careful charges of giant powder.

The shoes weigh 140 lbs. when new, and are attached to the bosses with hard-wood shims. Soft wood has been found use- less for this purpose. Three kinds of shoes are in use in the mill at present, and a comparative table showing the cost, life nd wear of iron per ton of ore crushed may be of interest :

Chrome Steel.

rorged Steel.

CasMron.

Cost per lb. at the mill, . 8 cents.

cents.

Si cents.

Weight when new, . 140 lbs.

137 lbs.

135 lbs.

Weight when discaided, 35 lbs.

40 lbs.

40 lbs.

Actual life, . 106 days.

72 days.

41 days.

Wear of iron per ton of

ore crashed, . . .3181b.

.431b.

.75 lb.

The cost of iron per ton of ore milled was, with the chrome- steel shoes, 2.5 cents; with the forged-steel, 2.75 cents; and with the cast-iron, 2.4 cents.

As the result of the above experiments, and taking every- thing into consideration, the chrome shoe was ultimately de- <5ided upon as the most economical at the present time. Forged- flteel, chrome-steel and cast-iron dies have been in use.

The chrome-steel dies were of the sectional type, which pos- sess some advantages in being readily removed from, and re- placed in, the mortar. They also give a more constant depth of discharge. On account of the short life of the die-top, how- ever, and the annoyance caused by chips of steel from the mine getting between the top and the base, they were discarded for a solid forged-steel die. The relative wear of the different dies is shown in the following table :

532 The Camp Bird Mine, Ouray, Colorado.

Chrome Steel.

Forged Steel.

Castrlron.

Cost per lb. at the mill,

Scents.

cents.

cents.

Weight when new,

76 lbs. (tope).

143 lbs.

140 lbs.

Weight when discarded,

22 lbs.

50 lbs.

50 lbs.

Actual life, .

41 days

80 days.

42 days.

Wear of iron per ton of

ore crushed,

.42 lb.

.36 lb.

.76 lb.

Cost of iron per ton of

ore crushed,

3.36 cents.

2.30 cents.

2.4 cents.

Chuck-blocks, 4 in., 8 in. and 1 J in., are employed to keep the depth of discharge as constant as possible. The height of dis- charge is normally 5 in., and at this the sliming is reduced to a minimum and the maximum crushing capacity is attained. Forty-mesh slot-screens have been in use until recently, but have been replaced by 25-mesh No. 29 wire-cloth. The wire- screen is infinitely superior and cheaper, having a greater dis- charge area, and the constant annoyance experienced by chips when the slot-screen was in use is entirely abolished. The bat- teries can also be fed very much lower than formerly, with desirable results.

The cost of a slot-screen at the mill is 1.49, and that of a wire-cloth screen {0.85. The former has a life of three days, or 46 J tons of ore, the latter a life of six days, which corresponds to the crushing of 98 tons of ore. Thus the slot-screen costs 8.2 cents per ton of ore crushed, while the wire-cloth screen costs- but .9 of a cent.

The discharge-area of the screens is 50 in. by 8 in. The stamp-duty is at present 8.11 tons (dry ore) per stamp per day. Sectional guides are in use on 40 heads of stamps. This type of guide was designed by Mr. W. MacDonough, superintendent of construction. It is a quick guide in turning stems, and is very firm and rigid in construction. As may be seen in the drawing (Fig. 6), specially-cast washers (d, d) are used, instead of the ordinary round washers, for the purpose of more securely holding the guide over its full width. The one-half inch bolt& (c, c) are put in crosswise, in order to prevent the splitting of the guides. On 20 of the stamps the Fargo guide is in use, but is not so satisfactory.

The water (20 gallons per minute) is supplied to the mortar through the feed-slot with 1 J-in. pipe. This method of feeding- the water insures a thorough mixture with the ore. For some

The Camp Bird Mine, Ouray, Colorado. 533

unaccountable reason, fewer stems have been broken since the back-feeding has been adopted. When front-feed was in use here (the water being supplied through five small pipes), fre- quent annoyance was experienced through the tendency of the pipes to jar loose and leak. They were also much in the way when repair-work was in progress.

Amalgamating-Praciice. — The plates are 16 ft. long, 58 in. wide, of raw annealed copper, J in. thick, and have a fall of 1 J in. per ft. They are delivered to the mill in 4-ft. sections. The method of preparing the plate for service is as follows : The sur- face is scoured thoroughly, by vigorous rubbing with tailings or a piece of brick, to remove all traces of oxide and expose the bright surface of the metal. Strips of blanket are placed on the table along the sides and across the line of junction, and the sections of copper securely screwed to the table with brass screws counter-sunk. Iron screws rust so rapidly that they are of little use for this purpose. The plate is now thoroughly washed with hot water, and again with a strong solution of lye. The quicksilver is applied a little at a time, and the plate thoroughly amalgamated by vigorous rubbing with a blanket-brush. A little dilute cyanide is used during this operation. A new plate, during the first few days it is in service, is dressed usu- ally every two hours, and little or no amalgam is removed, except, perhaps, from the head, until a coating has accumu- lated.

Geavrup and Dressing. — The methods pursued in the daily clean-up of the mill are as follows : The battery being hung up, the plate is carefully washed, the amalgam at the head (sometimes hard and crystalline, due, in the writers' opinion, to the manganese present in the ore) is slightly softened by sprinkling with a small quantity of quicksilver and rubbing with scrubbing-brushes, after which the amalgam, commencing at the bottom and working upwards, is removed by means of rubber scrapers. Knives are seldom used, except possibly at the very head. After the amalgam is removed the plates are again sprinkled with mercury, which is thoroughly spread and worked into the copper. Following this operation the plates are brushed with very fine whitewash-brushes, and riffled crosswise. During this latter operation the mercury is slightly drawn to the sides of the plate, consequently the brushes are

534 The Camp Bird Minb, Ouray, Colorado.

drawn lengthwise along the sides, from the bottom to the top. This finished, the feed-water is turned on and the stamps again dropped. The time of cleaning up and dressing is about 20 minutes to each plate. The plates are cleaned the full length at the morning clean-up, while in the evening the top only is cleaned, unless the ore is unusually rich.

The plates are dressed every three hours, and no mercury is fed into the mortar. Weak solutions of lye and potassium cyanide are employed while dressing, and lime is occasionally supplied to the batteries to neutralize the acidity of the feed- water and the ore. No difficulty is experienced in keeping the plates free from verdigris by these methods. An average extraction of 75 per cent, is obtained at this stage of the milling, with a resulting loss of only .142 to .166 oz. quicksilver per ton.

The amalgam recovered in the mill is immediately conveyed to the amalgam-room, and there cleaned and retorted. The impurities which adhere to the plates are very tenacious, and on this account it is necessary to grind the crude amalgam in mortars, for the purpose of mechanically separating the sul- phurets and sand. The clean-ups are submitted to two sepa- rate grindings. In the first, after softening with additional mercury and grinding for a time in hot water, the batch breaks, and the partially clean amalgam sinks to the bottom, while most of the impurities float on the top and are skimmed oK The amalgam remaining is then squeezed through canvas bags and freed from excess of mercury. It is then further cleaned by a second grinding, so that very few impurities remain. After being subjected to a further squeezing, the amalgam is retorted. The yield is about 40 per cent., and the fineness of the gold thus recovered is .740.

The sulphurets and other impurities in the ore have a ten- dency to foul the mercury, and it is therefore necessary to retort all of it before using it again in the mill. The gold is weighed and shipped daily to the mint.

The pulp from each ten stamps, after leaving the plates, is run to traps — simply wooden boxes, 12 by 15 by 8 in. — suspended on iron hangers, with a motion given them similar to that of a vanner. They make 180 strokes, of j-in. throw, per minute. On the discharge side they are fitted with long copper lips con-

The Gamp Bird Mine, Ourat, Colorado. 635

nected with the vanner-launder. The pulp is delivered to the center of the trap, and this and the reciprocating motion of the box prevents the settling and packing of the sands and concentrates, allowing ample opportunity for the amalgam and mercury, which escapes from the plates, to deposit.

The traps have proved very efficient, and at no time has the presence of mercury been detected in the cyanide solutions. Once a week the traps are cleaned and 50 oz. of mercury dis- tributed among the six.

The pulp, on leaving the plates and passing through the traps, is delivered to thirty-six concentrators. Sizing is carried on in pointed boxes, the pulp from each 20 stamps running to 6 machines ; and, as double concentration is in vogue, it is ele- vated and treated again on a second row of vanners.

The final tailings are delivered to the cyanide-works.

Concentration. — The concentrator equipment consists of 30 six-foot Frue vanners, and six Wilfley tables. The first row of vanners is fitted with amalgam-savers in the form of copper plates fitted to the pulp-distributors. The vanners are set up and anchored to massive sills which run the entire length of the building.

Too much care cannot be given to the erection of the con- centrators, if good results are to be obtained, the least lost motion in the machines being very noticeable in the results, both at the front and back end of the table. The machines on the coarse side run 190 revolutions per minute, and are given an inclination of 3 J in. in their entire length. On the slime side a speed of 182 revolutions is allowed, with an inclination of 2J in. The speed and inclination are based upon careful experi- ments. Corrugated belts are in use on the head machines in the front row. They give very good satisfaction in handling the coarsest of the pulp and have a much greater capacity, al- though the tailings have a slightly higher value and the result- ing concentrates are not quite so clean. However, in view of the second concentration, they are to be recommended.

The Wilfley tables have a speed of 240 revolutions per minute. They give good satisfaction, especially in regard to capacity, which is much greater than that of the Frue vanners.

All these vanners are equipped with sulphuret rollers, and the mud-boxes of each machine are connected with settling-tanks.

536 The Camp Bird Mine, Ouray, Colorado.

Little trouble is experienced from the belt elevators, which travel at a speed of 410 ft. per minute, lifting 15 ft. The pul- leys are key-seated and set-screwed, and an 8-ply belt is used, having a life of 14 months.

Lines of track are run in front of each row of vanners, to facilitate handling the sulphurets, which are trammed direct to the dryer-building. The dryer proper consists of iron- lined shoots or bins, set at an angle of 45°. They are 4 ft. wide and are fitted at the bottom with iron gates, for withdrawing the dried concentrates. In the center of each bin are coils of pipe heated with exhaust steam from the mill-engine. The concentrates remain in the dryer from three to four days, and by that time the moisture is reduced to about 8 per cent.

Concentration is carried on at a ratio of about 15 to 1, and the average extraction in the concentrating department is about 10 per cent of the whole, giving an average total saving, in the stamp-mill alone, of 85 per cent

The average composition of the concentrates during an ex- tended period has been :

Per cent.

Silica, 18.00

Galena, 7.04

Copper pyrites, 8.20

Iron pyrites, 30.15

Magnetite, 7.00

Blende, 16.60

Bbodonite, 4.80

CJalcite, 9.00

The analysis of the ore from which these concentrates were produced is as follows :

Per cent.

Silica and insolublea, 85.20

Galena, 60

Copper pyrites, 80

Iron pyrites, 6.60

Magnetite, 50

Blende, aOO

Rhodonite, 2.50

Alumina, 1.50

The analyses of the concentrates and the ore were made for the writers by Mr. W. F. Harris.

The Camp Bird Minb, Curat, Colorado. 537

The cost of milling the ore in summer is from 48 to 54 cents per ton ; in winter, from 68 to 72 cents per ton.

Power. — The boiler equipment consists of a battery of three Babcock and Wilcox 150-H.P. water-tube boilers, supplying steam to a 250-H.P. tandem compound Corliss engine. To this the main stamp-mill line shaft is direct-connected. By means of a counter-shaft, a 100-H.P. Westinghouse generator is con- nected, which, in turn, furnishes power to the cyanide mill, machine shop and carpenter shop. The Telluride Power Trans- mission Co. has erected a station for reserve electrical power, from which power can be obtained in case of emergency.

In summer (Fig. 7) a 7-ft. Pelton water-wheel, working un- der 175 lbs. pressure, supplants the steam equipment. During the latter part of the winter, when the water-supply is de- creased, owing to natural conditions, a dam (Fig. 8) is used for settling the water. The slimes accumulated by this dam are treated during the summer months by cyaniding.

The mills, shops, boarding-houses and offices are lighted by electricity. The exhaust steam from the engine, which has never over lbs. back pressure, is utilized for heating the mills by a system of radiators, as well as for running the dryer, the water of condensation being returned, by means of pumps, to the boilers.

A common store-house, both for the mine and mill, forms part of the plant equipment, all supplies being charged sepa- rately to the various operations.

Costs of Milling Per Ton of Ore.

CruBhing or break-. ( Labor, (0.065

ing, . . I Bepairs and maintenance, 0.006

Labor, 0.059

Wear of iron, 0.048

Screens, 0.009

Bepairs and maintenance, 0.065

Lubricants and sundries, . 0.002

Labor, 0.090

Amalgamation, . Quiclwilver, 0.007

Chemicals and sundries, . 0.001

Labor, 0.042

Repairs, 0.030

V 1.* J I L*bor, 0.042

steam neat, . Lubricants and sundries, . 0.006

Superintendence, day and night, 0.075

Total cost of milling, 0.707

Pulverizing,

Concentration,

I:

588 The Camp Bird Mine, Ourat, Colorado.

In these costs the separate treatment of the concentrates, per ton of ore milled, is not included.

Cyanide - Works and Treatment of TaUings.

General Description. — The cyanide-works (Figs. 9 and 10) are arranged for the direct treatment of the vanner-tailings They have a capacity of about 200 tons per day, but at the present time they treat 150 tons daily. Owing to the position of the mill, the tailings have to be elevated a height of 40 ft.,, and this is accomplished by a No. 4 centrifugal sand-pump, running at 650 revolutions. The column-pipe is 4 in. in di- ameter, and 315 gals, of pulp are delivered to the settling-vats per minute. The linings of the pump are of manganese-steel, and undergo erosion quickly, so that the life of a lining aver- ages about six, and under favorable circumstances eight to ten, weeks. A duplicate pump is kept in reserve, ready for immediate use. When worn out, the pump is removed to the machine shop, re-lined, and new collars, if necessary, are fitted on the shaft. The master mechanic, Mr. William Scheele, has arranged an excellent device for controlling the .suction opening; it is a sliding valve, of boiler-plate, set in a frame, and attached to the suction-nipple by set-screws. The slide is attached to a lever, which, in turn, is connected to a float. As the water rises in the settling-box the valve is opened wider, and vice versa. This arrangement makes it im- possible for the pump to take air, and the pump works very smoothly. A Cornish float was formerly in use, but it was not a success.

The cost of elevating the pulp, which settles in the leaching- vats, amounts to a total of 3f cents per ton, of which 3J cents is for power and cent for maintenance and repairs. A tail- ings-wheel for elevating the tailings is under consideration, and, though the first cost will be large, the writers are convinced that this will spieedily be balanced by the reduction in cost of power, and the greater freedom from wear and tear.

The pulp. is distributed in the vats by Butters and Mein dis- tributors, which have been found satisfactory, the slimes pass- ing off at three slime-gates (fitted with slats 4 in. deep, set in a groove), placed at equal distances round the circumference of the vat. No attempt ifl made to classify the pulp before de- livery to the vats, owing to the impracticable nature of the

Thb Camp Bird Minb, Ourat, Colorado. 539

ground. The separation of the slimes takes place in the leach- ing-vats, from which they are conducted and settled in the slimes-dam (Fig. 8), and stored for subsequent treatment during the summer months. The leaching-vats in the older portion of the mill are arranged for double treatment, and there are four sets of 100-ton vats and one set of 200-ton vats.

The bottom of the upper vat is set 4 ft. 6 in. above the top of the lower. It rests on girders of channel-iron, which, in turn, are supported on steel columns in the center and round the circumference.

A series of experiments were conducted on 100-ton and 200- ton charges, to determine the adaptability of these tailings to single direct treatment, and the results were so flattering that, in a recent addition made to the mill, two vats, 40 ft. in diameter, with a 6-foot stave, arranged for single treatment, were installed.

In the future additions to the mill, vats of even greater di- ameter, probably 60 ft., will be installed, for single treatment.

Some comparative notes relative to single and double treat- ment are given on page 545.

Grading-Tests. — A grading test of the product settled in the vats may be of interest :

(1) Product settled in a 24-ft. vat, 100-ton charge.

(2) Product settled in a 80-ft. vat, 200-ton charge.

(3) Product settled in a 40-ft. vat, 300-ton charge. Grading-Test (1). — Two of these vats are filled at once, each

vat getting about half the pulp.

Per cent.

Betained on 40 mesh, 12.60

60- " 22.90

80- " 12.60

100- 0.90

120- " 19.10

200- " 11.60

Passed 200- 20.30

Qradivg-Test (2). — This vat is filled alone.

Per cent.

Retained on 40-me8h, 17.60

" 22.60

" 14.80

" 1.60

.' 16.80

" 16.00

" 20.60

Passed

VOL. xxxin

.—33

640 The Camp Bird Minb, Ourat, Colorado.

Grading'Test (8). — The two vats, used for single treatment, are filled singly.

Percent.

Retained on 40'me8hy 11.80

" " 60- " 22.60

" " 80- " 12.fc0

" 100- " 1.00

" " 120- " 19.20

" " 200- " 10.00

Paaeed 200- 22.60

The leaching-vats are fitted with a filter-bed consisting of pine slats in. in width and 2 in. deep, placed in. apart In the wooden vats the slats are simply nailed to the bottom, and abut against an annular ring slightly rounded on the periphery, and placed one inch from the staves. The slats are also rounded on the top, and, to admit of free circula- tion of the solution, crozed on the bottom at regular inter- vals. Over the slats is tecked a layer of cocoa matting, 2 in. smaller in diameter than the floor of the vat. A 12-oz. duck filter-cloth, about 6 in. larger than the floor, is stretched over the mattiog, and firmly grouted down with an inch rope be- tween the ring and the staves. In the upper series of vats a heavier duck is required, the friction of the shovels being suffi- cient to wear out the cloth in about 5 months. In the lower series, however, an 8-oz. duck will wear for 15 to 18 months. The matting will last a considerable time, — 4 or 5 years.

A No. 4 centrifugal pump is used for returning the solution from the sumps to the storage-vats, or directly to the leaching- vats. Zinc shavings are used as a precipitant, and the pre- cipitating plant consists of four extractor-boxes, containing the strong solution. Each of these boxes is divided into six compartments, 36 in. long, 24 in. wide and 28 in. deep. Three boxes, each with seven compartments, 30 by 30 in. and 86 in. deep, are employed on the weak solution. The waste solution, before leaving the mill, is passed through two zinc boxes of seven compartments each. All the boxes are fitted with side-launders for the delivery of the zinc-gold slimes to the reduction-tAnk. The gold liquor is drawn off from the top of the tank thoroughly clear, and no filters are required in the zinc boxes.

Sulphuric acid is used for the treatment of the precipitates.

Thb Camp Bird Mine, Curat, Colorado.

and after a thorough washing and drying they are melted into bars on the premises. The system employed in cleaning up and smelting to bullion is described on page 546.

The Oyanidaiion.

(a) Double Treatment — Aft;er the charge has been sampled, leveled, and the requisite quantity of lime (found from acidity test on 100 gms. of pulp) added, the cyanide solution is ap- plied and allowed to percolate through the ore. A copy of the mill diary-notes, taken during the treatment of a charge of tailings, will illustrate the current practice. It is to be under- stood that the treatment varies as changes in the nature of the ore are manifest.

Charge No. 127. Vat No. 5 (upper). Ore, 200 Tons.

Tom KCN.

Strength of KCN.

Da.

Hoar.

.07 per cent.

June 9

10 A.M.

.26 "

" 10

3 a.m.

.25 "

" 10

5 p.m.

" 11

2 a.m.

1a.m.

.26 "

8 P.M.

At 3 P.M., June 13th, the charge was shoveled to the lower vat (No. 5). This required 6 men 8 hours.

Charge No. 127. Vat No. 5 (lower). Ore, 200 Tons.

Tons

Strength

Kcn.

of KCN.

1 23

.30 per cent

.25 "

Tons W t r

Day.

Hour.

June 14

1a.m.

" 14

3 p.m.

a 14

11 p.m.

" 15

8 a.m.

10 P.M.

" 16

11 A.M.

" 17

2 p.m.

The charge was then allowed to drain until 2 a.m., June 18th. The residues, after sampling, were discharged by 10 A.M., Jui\e 19th.

Thb Camp Bird Mine, Ourat, Colorado.

Samples taken from the charge during the leaching period showed the following per cent, of extraction :

Day.

Hour.

Per Cent, of Extraction.

June 10 " 11 " 12 " 13

3 p.m. 3 p.m. 2 p.m.

2 P.M.

The charge was then allowed to macerate 12 hours with a. .80 per cent. KCN solution, and gave extraction as follows :

Day.

Hour.

Per Cent, of Extraction.

June 15 " 18

7 a.m. 2 a.m.

76.5 1

A final tailings sample was taken, just before discharging,, which showed an extraction (by assay) of 77.25 per cent. The rate of leaching, in the upper vat, varied from 11 gals, to 7 J gals, per minute. It was about 15 gals, per minute in the lower vat (No. 5).

The values, as will be noticed, yield rather slowly to the solvent action of the solution. This is no doubt partially due to small particles of coarse gold, which are apt to be enclosed in the larger grains of sand. The system employed in charging the vats is to fill two of the 100-ton vats at once and the 30-ft. and two 40-ft. vats singly. A good deal of concentration goes on in vat No. 5, and the extraction-percentage is corres- pondingly decreased. The extraction cited in charge No. 127 is below the average of the 100-ton vat extractions. It is due entirely to the elimination of a great percentage of the slimes,, and is very much below the average extractions obtained in single treatment in the larger vats. The percolating solutions- from all the vats are regularly titrated for free cyanide, and,, when required, for total cyanide, at least once every eight hours, and frequently several times in a shift. The titrations- serve as a guide in controlling the treatment of each vat charge. A few of the titrations made on the outgQing solu- tion from charge No. 127 showed :

The Camp Bird Mine, Ourat, Colorado. 543

At 8 A.M. on the 10th of June, .01 per cent, free KCN and ,03 per cent, total cyanide.

At 8 A.M. on the 11th of June, .09 per cent, free KCN and ,15 per cent, total cyanide.

At 8 A.M. on the 13th of June, .19 per cent, free KCN and ,195 per cent, total cyanide.

The large quantity of double cyanide found in the weaker solutions first coming from the charge is probably due to the nascent HON, liberated from the action of acid salts unit- ing with the zincate of potash contained in the working solu- tion, and forming zinc potassium cyanide.

The gold-values in the solution show a gradual rise from a few cents at .005 per cent, test to their maximum value at .22- ,24 per cent., again declining to 20-35 cents per ton when the solution falls in cyanide to .03-. 04 per cent, when the residue are discharged.

A total consumption of cyanide of from 1 lb. to 1.25 lbs. is found in double treatment; 0.7 to 0.8 lb. is consumed by the cyanicides (chiefly copper minerals), about .125 lb. is discharged with each ton of tailings, and about as much more, per ton of ore, is run to waste out of the mill, the combined gold being removed, in part, by the waste zinc boxes. A small amount is rendered inert, of course, during the precipitation of the bullion in the zinc-extractor boxes, but a portion of the cyanide con- tained in the double salt of zinc is regenerated, when leaching, as potassium or sodium cyanide. The consumption of cyanide due to zinc precipitation is usually so small that it is scarcely appreciable.

A great deal of cyanide is consumed after the charge has been shoveled to the lower vat, and the solution applied. This is probably due to the oxidation of some of the cupriferous minerals. The consumption in the single direct treatment system is approximately 0.7 lb. per ton, about .35 to .45 lb. of which is due directly to the presence of cyanicides in the tail- ings ; the remainder is lost by dilution and by the discharging of a certain amount with the residues. The lower consump- tion is solely due to the fact that there is no shoveling, and consequent aeration and oxidation of the baser minerals.

Exhaustive experiments on a large scale have recently been carried put with a view of recovering the cyanide contained in

544 The Camp Bird Mine, Oubat, Colorado.

the waste solutions. It was clearly demonstrated that a large percentage of the free cyanide, and that combined with the zinc, could be recovered with ease and profit, and converted into an effective extracting solution.

The cyanide that combined with the copper could also be recovered cheaply, but, in view of the low chemical consump- tion obtaining, it was not deemed advisable to install a " Re- covery " plant.

(b) Single Treatment. — The treatment of the tailings is carried on much in the same manner in single as in double treatment. The solution, usually 0.26 per cent. KCN, is kept in circulation for seven or eight days, or until the assays of the samples, taken at regular intervals from the charge, show that an adequate ex- traction has been obtained. When the vat is filled, care is taken pot to drain the charge of water more than is necessary to en- able the sampling and leveling to be done comfortably. It seems important to allow the particles of sand to be surrounded with a " water-cushion," which is subsequently displaced by a " solution-cushion." If the charge is completely drained be- fore applying the solution, the sand packs tightly, and subse- quent leaching operations are much retarded. No vacuum is employed in either of the systems, as no difficulty occurs in obtaining a good rate of percolation.

An example, illustrating the single treatment, is copied from the mill diary, and the percentage-rate of extraction after cer- tain periods may be of interest.

The charge— No. 267, vat No. 6, 300 tons— was filled at 9 A.M. on Dec. 29, 1901, and, after sampling and leveling and adding the requisite lime, 40 tons of .06 per cent. KCN were applied at noon, and also at 10 p.m. of the same day. A .25 per cent, solution of KCN was then applied, and kept in circu- lation for seven days, with occasional periods of maceration. The charge was then allowed to remain in contact for 12 hours, drained partially, and weak washes of .06 per cent KCN, amounting in all to 60 tons, were applied. (The solu- tion washes are run on till the vat is filled to the brim, thus making use of the slight head obtained to aid percolation.) When the weak solution had drained sufficiently, about 86 tons of water were applied, and by midnight of Jan. 8, 1902, sufficient cyanide was removed to allow of the residues being

Thb Camp Bird Mine, Ourat, Colorado. 545

sampled and discharged. The actual time of treatment was 11 j days, and assays taken from the pulp during that time, at intervals, show the following rate of extraction :

Per Cent.

Extraction.

No. Time.

Gold.

Silver.

(1) 1 P.M. Dec. 30, .

. 12.40

(2) 3 P.M. Jan. 1, .

. 68.60

(3) 2 P.M. Jan. 3, .

. . . 68.00

(4) 2 P.M. Jan. 5, .

. . . 77.60

(5) 4 P.M. Jan. 7, .

. 86.00

(6) 12 M. Jan. 8,

. 86.70

63.00— Pinal tailings.

The rate of percolation on this vat-charge was about 17 gals, per min. for the first two days, and gradually slackened to from 10 to 12 gals, near the end of the treatment. The total quantity of solution received, including water-washes, was 840 tons, or 1.18 tons per ton of tailings.

Comparison of Single and DovJble Treatment.

Referring to the grading-tests on page 589, it will be seen that the material settled in the 800-ton vat had a greater fine- ness than that settled in the 200-ton vats, and was also slightly finer than the material caught in filling two of the 24-ft. vats at once. To this fact may partially be attributed the increased extraction in the single treatment. A comparison of the results obtained on a large number of vat-charges indicates that an increase of 15 per cent, is found in the quantity of leachable material deposited in a given time, and an increase of 5 per cent, in the gold-extraction in 20 per cent, longer time.

At the same time there is a decrease of cost in labor of 9 cents per ton, and in the cyanide-consumption of 10 cents per ton ; and, taking into consideration the increase in cost of con- structing a plant for double treatment, the advantages of single treatment on these tailings are so obvious that further argument would be superfiuous.

The tailings are discharged by sluicing throughout the year. A pressure-pump is used in winter, however, to pump the slimy water from the dam to the hose-line. With a 8-in. hose, IJ-in. nozzle, and a pressure of 60 lbs., one man can discharge 100 tons and clean the filter-bottom in two hours. Bottom-discharge doors are used.

546 The Camp Bird Mine, Ouray, Colorado-

The Precipitation of the Bullion.

The zinc used in the precipitating-boxes is received in sheets, 7 ft. long and 18 in. wide, costing 7.66 cents per lb., and are cut in the machine-shop to a thickness of in. A Hampton lathe is used, and, winding 5 or 6 sheets on the man- drel at once, a man can cut 140 lbs. per day, about one-half lb. of which is waste. The consumption of zinc per ton of ore treated is .45 lb. ; the greater part of this is consumed by the refining process, and but a small proportion is dissolved in the boxes. The cost of cutting the shavings is 2.7 cents per lb., bringing the total cost at the mill to 9.36 cents per lb., or 4.66 cents per ton of ore. The precipitation of the bullion offers few difficulties, and is usually very perfect.* Occasionally, how- ever, when the solution carries much copper, the degree of pre- cipitation will be poorer, especially in the weak boxes, and cases will sometimes be observed when the weak solution has re-dissolved the precipitated gold, running out of the boxes many times higher in value than when entering.

The remedy for this is periodical flooding of the weak boxes with a stronger gold-bearing solution ; frequent re-arrang- ing of the zinc in the compartments ; and, perhaps, occasionally entirely removing the zinc from the boxes, placing it in the strong boxes, and putting in its place zinc coated with a metal- lic film of lead or mercury. ISo effort is now made to prevent the depositing of the copper on the zinc with the gold, as it was found that, when pains were taken to keep the copper out of the extractors, the solutions speedily became over- charged, and eventually the copper would come down in such a strong coating that the bullion was almost if not quite ex- cluded. The overcharging of the solutions with the double cyanide of copper has a most vitiating effect on their dissolving power, and a solution thus fouled will take very much longer to make the same extraction than would a fresh solution ; and in some cases the same extraction cannot be attained at all, even with a prolonged contact. A solution fouled in this way is usually very low in its dissolved oxygen-content, and it is probable that this influences the rate of extraction to some ex- tent. A little copper in the solution is undoubtedly a very effi-

Normally the sumps carry from 1 or 2 grains to 4 or 6 grains of gold per ton.

The Camp Bird Mine, Ouray, Colorado. 547

-cient aid in precipitation, and it is only when the copper is allowed to accumulate that difficulties are encountered here in the extractors. The sump solutions usually carry .015 to .020 per cent, copper; and, as long as this is kept fairly constant, sat- isfactory results ensue. An average of a number of analyses on the incoming and outgoing solutions shows :

Per cent. Cu. Per cent. Zn. Strong gold tank solation, . . . ' . .025 .073

Weak gold tank solution, 0188 .036

Strong sump solution, 018 .0745

Weak sump solution, 017 .037

The solutions, before pumping to the leaching-vate, are Aerated for an hour. This raises the dissolved oxygen-content <jon8iderably, but, on standing for some time after aeration, some of the dissolved oxygen diffuses in the atmosphere.

Estimations of the dissolved oxygen in the solution at various stages in the process are :

(1) Solution in sump before aerating and standardizing, 2.30 . per liter.

(2) Solution as pumped to leaching-vats after aeration,* 7.85 . per liter.

(8) Solution after standing on vat-charge for one hour, 6.80 . per liter.

(4) Solution after leaving the vat at gold tank, 2.22 . per liter.

(5) Solution after leaving the zinc-boxes, 0.82 mgm. per liter.

The weak solution contains about the same amount of dis- solved oxygen in all cases except when leaving the zinc-boxes, where it is slightly higher than the. strong solution, containing, in several cases, 1.50 . per liter.

Clean-up of the Zinc-Boxes. — This is made monthly. The cyanide solution is displaced by running a stream of water through the boxes, which thoroughly washes the zinc in each compartment; the fine sludge is then screened, sluiced down the side-launders, and settled in the reduction-vat. The re- maining zinc is replaced in the upper compartments, the lower end of the box being replenished with fresh zinc, and the solu- tion, strengthened for a few hours with a little cyanide at the head of the box, is again turned in. There is no handling of the valuable precipitates, everything being sluiced by gravity

548 Thb Camp Bird Mine, Ouray, Colorado.

to the settling-vat. When all the extractors have been deprived of their zinc-gold slimes, the vat is allowed to remain undis- turbed for a few hours. The supernatant liquor being siphoned off as closely as possible, sulphuric acid (sp. gr. 1.84, and cost- ing 1.80 cents per lb. at the works) is applied, with constant stirring, till all action ceases. The vat is then filled with water settled, the liquor siphoned ofl* into a settling-tank directly under the reduction-vat, and a succession of water-washes ap- plied as rapidly as possible, siphoning off as soon as sufficiently clear. The small amount of values contained in the wash-set- tling vat is cleaned up at long intervals. It is desirable to leave a portion of the sulphates behind, in order that a regulus or matte may be formed in melting. A considerable quantity of the copper is matted off in this way, leaving a comparatively fine bullion.

After washing, the slimes are partially dried on a blanket- filter and removed to a hearth furnace (hearth 6 ft. by ft.), and subjected to calcination for four hours at a dull red heat. When cooled, the product is transferred as required, mixed with a suitable flux, and smelted in graphite crucibles, in two wind furnaces (20 in. by 20 in. by 28 in.). The flux found to be most suitable is composed of borax, 4J parts; soda, 2 J parts ; carb. potash, J part ; silica, 2 J parts. The flux is mixed with the calcined precipitates in the proportion of 1 to 2.

No niter is used in the preliminary melt, as it is preferable to combine the base metals with sulphur, rather than attempt to remove them as oxides. The corrosion of the crucibles i& also slighter than when niter is used. When the charge is thoroughly quiet and fluid, the slag is skimmed off repeatedly with a drop-forged iron ladle, fitted with a handle bent almost at right angles, to save the attendant from the heat of the fire. The crucible, when sufficiently filled with molten metal, is re- moved, and the contents poured into moulds. The casts are quickly emptied and thrown into a tub of water, to facilitate the removal of the matte. The latter, in addition to some bullion value, contains about 60 per cent, of copper and a small per cent, of zinc. The bars from the first melt are freed from matte with a few blows of the hammer, and are re-melted in No. 20 crucibles, refined with a little niter and bone-ash, and carefully cast into bars of 500 oz. weight, pickled in dilute acid,

The Gamp Bird Mine, Ouray, Colorado. 549

cleaned, and packed ready for shipment. The first pouring is conducted at a high temperature, to insure the ready and clean removal of the matte on chilling. The final melt is, however, poured at a much lower temperature, and the finished bars are very tough and quite malleable. The slag and matte are bagged, and shipped to the smelter.

In a recent clean-up, in which over 5000 oz. of bullion was obtained, 800 oz. of matte was formed in melting, containing .345 per cent, of the total value, and 7200 oz. of slag in which .62 per cent, of the total value was locked up for a time. The average value retained by the matte and slag may be safely es- timated at a trifle over 1 per cent, of the value contained in the precipitate.

The matte carries a greater silver value (usually 2 to 1) than gold, while, in the slag, values are about equally divided.

The labor involved in cleaning the extractors, tending acid refining and subsequent drying, calcining and melting, the sulphuric acid used, and the fluxes, crucibles and fuel, cost altogether (on an average of a number of clean-ups) one cent for each dollar in bullion produced.

The total working-costs per ton are given in the following table :

The Cost of Treatment per Ton.

Labor, 10.2026

Cyanide, 0.2860

Zinc 0.0466

Lime, 0.0140

Elevation of pulp, 0.0375

Cleaning ap, refining and melting, labor, supplies, . 0.0437

Sundries: Filters and sbovels, etc., 0.0065

Chemical supervision and assays, 0.0850

Total cost, S0.7218

These costs are for the combination of single and double treatment at present in vogue here ; should all of the mill be changed to single treatment, as is probable, the future working- costs would be reduced 16 to 18 cents per ton, on the same monthly tonnage.

The plant for the treatment of dam slimes is at work dur- ing the four summer months, and has a capacity of 60 to 76 tons per day.

550 the camp bird minb, ourat, colorado.

Postscript.

(February 20, 1903.)

Since writing the above, a filter-press has been installed to facilitate the cleaning up of the zinc-gold slimes. The press is an open-delivery, two-eyed pattern, with flush-plates and dis- tance-frames, forming a cake 1 inch thick. Each press-charge of twenty-four cakes weighs, when dry, about 350 pounds. The cakes are 19 inches square, and are formed between layers of heavy woollen filter-cloth covered with filter-paper!

During the clean-up of the precipitation-boxes, the liquor in the reduction-vat is continually* siphoned into a small sump, And elevated by a Pohle air-lift 5 feet into a montejus and from theuce forced by air-pressure through the press, to remove any solid matter. The contents of the press are added to the slimes remaining in the vat, and the mass subjected to treatment with sulphuric acid, with constant mechanical stirring.

When the reduction has been completed, the refined slime and acid liquor is delivered to the monteJuSy and kept, by com- pressed air, at a pressure of 60 lbs. for two or three hours. This contact under pressure with dilute sulphuric acid removes much of the copper, leaving a very pure product for subse- quent melting. The contents of the montejus are forced into the press, and the liquor, heavy with copper and zinc, re- moved ; the press-cakes are washed by water under pressure to remove sulphates, and finally partially dried with compressed air. When removed to the melting-room, for drying and melting, the cakes contain about 17 per cent, moisture, and are tolerably free from sulphates.

The filter-press, with the montejus has proved a very valuable aid in the monthly clean-up, rendering the mechanical loss of gold practically impossible, and saving considerable time.

The writers are in receipt of " The Camp Bird Gold Mine and Mills," by Mr. H. A. Titcomb, reprinted from the School of Mines Quarterly, New York, November, 1902. It is regretted that this publication was received too late for detailed reference in the body of this paper.

Production Op Puddled Iron By Mechanical Means. 551

Puddled Iron and Mechanical Means for its Production.

BY JAMES P. ROE, POTTSTOWN, PA. (New York and Philadelphia Meeting, Febroary and May. 1902.)

Steel has occupied such a prominent position in most minds during the last thirty years, particularly since the introduction of the basic open-hearth process (by which the field from which the raw material could be obtained has been so widened), that little attention has been made to improvements in puddling iron. In fact, the general tendency seems to have been to ac- cept the prediction that puddled iron is doomed. Events have in a measure justified such a forecast, due in large part to the introduction of mechanical appliances and operations with large units in the manufacture of steel, from which much lower costs have resulted. But this general tendency has met checks in certain directions. This is notably the case where the fin- ished product is a welded one, or is subject to oxidation, to shock or to vibration ; and, as far as the writer's observation goes, the bond (which is largely a mechanical one) is not as close and lasting between steel and tin or zinc as between iron and the same materials. The field still open for puddled iron is, therefore, a large one, provided the low costs of steel-manu- facture can be approached.

The process of puddling is one of the most interesting in ihe metallurgy of iron, as the reactions and the changes effected are apparent. The subject has had the strongest fascination to the writer from boyhood, and has led, not unnaturally, to a close study, which long ago resulted in the conviction that it could be successfully carried out with large units and by me- chanical means. That others have also drawn these conclu- sions is shown by many undertakings, though there have been few such attempts during the last twenty-five or thirty years.

Puddling consists, essentially, in the removal of most of the carbon and silicon, and part of the phosphorus and sulphur

652 Production Of Puddled Iron By Mechanical Means.

from pig-iron by agitation, while molten, in the presence of suitable cinder and gases of the right composition and temper- ature. These are, broadly, the conditions up to the period of balling, which final operation will, of necessity, differ when car- ried out by manual or mechanical means.

The process developed by the writer is being carried out in the machine or furnace illustrated by Figs. 1, 3 and 4.

The general framing consists of two side-plates, suspended from a trunnion on each side, carrying the whole machine, and these trunnions rest upon roller-bearings supported by an ele- vated framework. The side-plates are extended underneath, forming segments of circles, to which the operating-racks are secured. These gear into pinions driven by a reversing-engine. Between the side-plates are four distance-pieces, which form rders from one trunnion to the other. The stack-bases and the angles under the bottom also serve both to form part of the framework and to strengthen it.

The bottom, consisting of a series of water-cooled parts, rests upon the angles referred to and supports the working-bottom of magnesite brick. This material is also used to line the end and sides, up to the wash-line of the cinder ; the sides above the <jinder-line, the roof, and the lining of the four stacks being built of fire-brick.

At present, the furnace is fired by means of crude oil and blast; but coal or gas can be used, should convenience or eco- nomical reasons require it. Oil was adopted in the present in- stance on account of convenience of application and ease of reg- ulation. The fuel is introduced through the two trunnions, which form eflicient combustion chambers, and the flames di- rectly impinge on each other at the middle line of the furnace, thus producing a most intense and thorough combustion. The flames then pass to the four converging stacks, two of which are at each end of the furnace, and by this means a complete filling of the chamber is assured.

The whole of one end of the furnace is closed by a door, built up of removable sections, and suspended from a shaft running across the furnace. The door is opened and closed by two side connecting-rods, which connect the bottom girder of the door to a cross-head operated by a hydraulic cylinder under the furnace. Parallel motion in the cross-head is assured

Production Of Puddled Iron By Mechanical Means. 553

by means of piuious at each end, engaging in racks fastened to the side-plates of the machine. The closed door is locked by means of wedges, operated by hydraulic cylinders, which pass through the side-plates and the connecting-rods. The wedges also aid in making tight the joints of the door.

The top-, bottom- and side-edges of the door are made with a J-inch radius in order to crush and grind out any cinder left on the sill, lintel or jambs at the time of discharging the ball. The sill and lintel are formed with water-cooled convex surfaces (extra heavy pipe), to chill the cinder in making the joint before charging, and to make it crush and part more easily when the door is closed after discharging.

The bottom is rectangular in plan, being about 20 ft. by 8 ft. 8 in. in the clear, while the sides and ends are straight and stand at right angles to the bottom. The form of the furnace is, therefore, the simplest possible, and the one which is the most easy to maintain. The high roof in the middle gives room for flame development. It slopes down, to direct the flame against the bottom, and rises again to allow sufficient space for the wash of the bath at the ends.

The machine can swing through about 65 degrees on each side of the center line of the trunnions. It is, therefore, a puddling-furnace in which the necessary agitation for produc- ing an intimate mixture of the molten metal and oxides is ob- tained by allowing them to run down-hill, first in one direction and then in the other, and suddenly arresting them at the bottom. The subsequent balling of the iron, when it has come to nature, is produced by precisely the same means.

It has been sought to embody in the present eflbrt, as far as possible, the general practice in steel-works ; since there is but one period in the production of iron (that from the beginning of crystallization to the squeezing of the mass) where the change from pig-iron to wrought is necessarily different from that to steel.

The bottom, sides and ends of the furnace, being formed as described, are intended to possess relatively permanent charac- teristics, thus differing radically from the cinder bottom and sides, fixed with ore, from which much of the cinder necessary for puddling is obtained in the ordinary furnace. It is neces- sary, therefore, to charge into the puddling-machino, as an

554 Production Of Puddled Ibon Bt Mbchaxical Mban8.

equivalent, molten cinder which is melted in an auxiliary fur- nace designed for the purpose. The tap-cinder from the ordi- nary furnace is used for this purpose, and is not an active puddling-agent. It serves principally to seal the door-Joints ; cover and protect the hottom in a measure; to present a me- dium for retaining the phosphoric acid ; to form a lubricant as the iron comes to nature and is massed ; and, finally, to act as a welding-cinder in the ball. Roll-scale is added during the process, to act as the principal puddling agent

It is intended to use molten iron from a blast-furnace by charging it into a mixer, and drawing the iron from that as needed by the puddler. At present a cupola is used. This latter, however, is open to two objections : greater cost and in- creased difficulty in obtaining low sulphur.

The molten iron (in the existing machine varying from 300Q to 4000 pounds) is poured through the charging-hole immedi- ately after the cinder, and as soon as the iron is charged the machine is oscillated two or three times. Then the oxidizing agent (roll-scale or easily reduced iron-ore) is added by means of a long spoon (made of a piece of pipe, cut in two longitudi- nally), which is run in through one of the end peep-holes,, given half a revolution and withdrawn, thus evenly distributing the scale through the bath. This is continued between oscilla- tions until sufficient scale has been added. This stage is indi- cated by free iron ceasing to run on the bottom, or the bath rising for the high boil. This latter is much more active than in an ordinary puddle-furnace. Large volumes of carbonie oxide are emitted, which burns above the surface of the bath to carbonic acid, materially raising the temperature of the fur- nace and the bath without additional fuel. During the periods- of scaling and boiling, as the bath descends the inclined hearth,, it is thoroughly agitated and uniformly mixed : in part, by the lower strata being retarded by friction on the bottom, thus al- lowing the upper strata to flow over the lower ; and, more largely, because, as the direction of the bath is suddenly ar- rested at the end, it turns over upon itself precisely as an ocean, wave does.

As the iron comes to nature and thickens, the progress down the hearth from end to end- becomes slower, so that the clusters pass slowly through the zone of highest temperature and

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Production Of Puddled Iron By Mechanical Means. 555-

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acquire the heat necessary for thoroughly welding the whole together in the ball. This massing, or balling, is accomplished by increasing the angle of the hearth so that the mass slides with sufficient momentum to compress and solidify itself. This mass, or ball, has a length about equal to the width of the machine, a width of about 3 ft. 0 in., and a height of 24 to 30

in. When the balling is completed, the side-rod wedges are

Fio. 1.

Hi

(ieneral View of Roe's Puddling-Machine.

withdrawn. As the front end of the machine descends, the door is opened and the mass is discharged by gravity directly into the squeezer. Any free cinder that may exist is discharged ahead of the mass, and falls in front of the squeezer. The door is then closed and locked, the cinder is poured in, and the machine is ready for the next heat.

Before following the puddled mass further, it is desirable to- call attention to the squeezer.

556 Production Of Puddled Iron By Mechanical Means.

The coffee-mill squeezer is almost universally used to-day, in conjunction with the ordinary process of puddling iron and working with balls weighing about 180 pounds. Although it is in this case probably as effective a mechanical device for a given end as was ever designed, it is not equally well-fitted for handling masses now weighing 4000 pounds, and which, in the future, probably will weigh 10,000 pounds, since the product sought is to be of square or rectangular section.

Hence a special squeezer had to be designed to meet the

Fig. 2.

Hear View of Hydraulic Squeezer.

conditions, and it took the form shown in Fig. 2. Hydraulic power was selected. The pressure is applied in one horizontal direction, by means of a front girder operated by the cylinder in the rear; and, at right angles to this, it is applied by means of the two end-cylinders. At present the bloom has a fixed length of 54 in. and a width of 24 in. The vertical pressure is applied by means of the top-cylinder. In order to increase the final pressure, an intensifier is mounted on the squeezer, which raises the pressure from the initial 600 pounds to 2500 pounds per square inch, thus giving a pressure of 1800 tons on

Production Of Puddlbd Iron Bt Mechanical Mbans. 557

the top area of the bloom. All of the facing-plates which come in contact with the mass are Bcctional, and have spaces between them for the egress of the cinder as it is squeezed out of the bloom.

The return motions of the various parts are eifected by

Fig. 3.

Longitudinal Section of Boe's Paddling-Machine. Scale same as Fig. 4.

smaller hydraulic cylinders, and, by similar means, the bloom is pushed from under the head-piece to the open front.

The whole is mounted upon four wheels, which run on rails extending in front of and parallel to a series of puddling-mar chines. One squeezer, therefore, would take the balls from all the furnaces and deposit them at a point convenient to the blooming-mill.

VOL. xxxni.— 34

d58 PRODUCTION OF PUDDLED IRON BY MBGHANIGAL MEANS.

The specific object in having a movable squeezer is to avoid any delay at this important period, as it is vital that the iron shall be put together before the projecting clusters cool. Be- sides this, rapid oxidation takes place when the ball is exposed to the atmosphere, thus causing a loss, and producing an infu- sible oxide, which tends to prevent welding and a thorough removal of the cinder.

Fig. 4.

Cross-Bection of Boe's Puddling-Machine.

The squeezer has proved very effective in shaping and solidi- fying it product There has been some trouble in freeing all of the blooms from cinder; but, judging from the number which have been so freed, and from the fact that the trouble is not in an aggravated form in any, it is believed that, by giving the cinder more freedom for egress, the result will be fully as satisfactory in this direction as in the others. All the opera-

Production Of Puddled Iron Bt Meohanigal Means. 559

tions on the bloom, after it has left the squeezer, are identical with those now applied to steel, thereby extending the economy of production to the finishing-mills.

Comparison seems so essential to many conclusions that it is almost necessary to point to some features in the Cort process, as improved by Rogers, in order to obtain a just conception of the present effort.

The conditions throughout the bath, or heat, in manual pud- dling, lack uniformity. This is recognized by all practical puddlers when they select a bar for testing. This lack of uni- formity is cured, in a large measure, at the finishing-mills by piling the good, bad and indifferent together, thus producing a mean that meets requirements. Hence, apart from the ina- bility of manual means to furnish a mass of suflicient size to finish direct, the product so made would vary so much that the proportion of inferior material would condemn the whole. On the other hand, the product of the machine under discus- sion is relatively uniform throughout a given heat, and is, therefore, well-fitted to roll directly into a finished product. This can be done, provided there is work enough, that is, a sufficient number of reductions in section from the squeezer- bloom to such product. The samples of iron plates and an etched section of squeezed puddle-ball, made by this process, go far to combat the usual statement that repeated working and heating of iron is necessary to produce a good product. This statement is illogical. It is impossible to conceive that there can be any inherent virtues in a second or third heating and piling, other than accomplishing something that had not been done in the prior heatings.

The requirements in the material for good results in rolling or forging iron or steel are homogeneity, mass enough to give opportunity for the necessary work (reduction of section) and to retain the temperature, and pressure enough (heavy and effective machinery) to accomplish the desired end before the heat is dis- sipated. This has been confirmed in modern steel production.

The puddler and squeezer, although presenting some of the shortcomings inevitably associated with being the first of their kind, have, in the main, fulfilled their mission of development satisfactorily, as is shown by the following summary of results in conjunction with the samples obtained.

560 Production Of Puddled Iron By Mechanical Means.

The pig-iron used has varied in composition as follows :

Sulphur, 0.03 to 0.26 percent.

Phosphorus, 0.50 " 1.35 "

Snicon, 0.60 " 1.40 "

Many of the heats have shown a satisfactory elimination of phosphorus, and, as was to be expected, this elimination has been found to depend upon the composition and condition of the cinder and the manipulation of the bath during the period before the iron comes to nature.

Some elimination of sulphur has been shown, but, as a gen- eral rule, this element should be kept as low as possible in the iron charged. Those heats which have been made with iron taken directly from the blast-furnace have shown the special advantage of such a practice in this respect The cinder used has a normal composition of about sulphur 0.30, phosphorus 1.73 and silica 20 per cent. Ordinary roll-scale was used for the additions.

The weight of pig-iron charged has generally been between 3000 and 4000 pounds, although some heats as low as 250& pounds have been made. The average is 3500 pounds.

The weight of cinder has varied considerably. It has been found that about 500 pounds per ton of iron (22 to 25 per cent.) is the proper amount. The amount of scale used has run from 350 to 550 pounds and depends entirely upon the individual characteristics of the heat, such as the character of the pig- iron, the temperature of the bath, etc., just as it does in the or- dinary process.

The time required to make a heat has, of course, varied very much, especially at first, running from 24 to 102 minutes. The average duration is 48 minutes, but it is believed that 40 min~ utes for a 4000-lb. charge will be the average under regular running conditions. This would mean from 15 to 18 heats per turn of 12 hours, or a product of from about 27 to 32 tons of rolled slabs or blooms.

While some heats have shown a loss, and others a gain, be- tween pig and slab, the indications are that the weight of the rolled slab will be about equal to that of pig-iron charged, or will only slightly exceed it. The loss from slab to finished plate, however, runs from 5 to 6 per cent., thus slightly exceed-

Southbrn Limit Of Pennsylvania Anthracitb-Bbds. 561

ing that of steel, the diflTerence being due to the iron being heated to a higher temperature. The difterence in finishing- loss is, however, more than compensated for by the fact that all of the iron made is in the slab, there being no crop-ends, such as are necessary when steel-slabs are rolled from ingots. The loss from pig to finished plate, when using the ordinary puddling-furnace and piling muck-bar, is about 16 per cent.

The physical tests made on this material show better results than those from plates of similar analysis made from ordinary puddled iron. For instance, the samples obtained from plates containing sulphur 0.016, phosphorus 0.10 and carbon 0.05 per cent, give an ultimate strength of 51,000 pounds per square inch, with an elongation of 24 per cent, in 8 inches; while that from a plate containing sulphur 0.019, phosphorus 0.13 and carbon 0.10 per cent, gives an ultimate strength of 62,000 pounds per square inch, with an elongation of 23 per cent, in 8 inches. The latter is a material which may again open to iron the large field of shipbuilding. The above results, together with the entire absence of blisters, show the high grade of product obtained.

It is, of course, somewhat difficult to estimate the probable cost in a properly organized plant from data obtained in work- ing a single machine under experimental conditions ; but the indications are, and it is confidently believed, that slabs and billets, and probably the finished product, will be produced at a cost not exceeding that of ordinary steel.

The Original Southern Limit of the Pennsylvania Anthracite- Beds .

BY BENJAMIN SMITH LYMAN, PHILADELPHIA, PA. (New York and Philadelphia Meeting, February and May, 1902.)

The question of the original extent of the anthracite-beds of Pennsylvania has often been raised ; and even discussed with reference to the probability of their present existence under the New Red, a matter of immense practical importance. So high an authority as my revered master, J. P. Lesley, Honorary

562 Southbrk Limit Of Pennsylvania Anthracitb-Bbds.

Member of our Institute, has repeatedly supposed that they once extended over a great part of the southeastern corner of the State, at least over the Azoic core of the South Mountain range, and, say, as far southeast as Trenton, N". J. yet (on the occasion of his last attendance at a meeting of the Acad- emy of Natural Sciences), he argued unanswerably against the smallest probability of their present existence beneath the Mesozoic rocks of that region. But, notwithstanding his sup- position as to the original extent of the anthracite, he would be the last man to maintain that the question is beyond fur- ther discussion, or to admit, what some exacting spirits seem occasionally to have believed, that our State geological sur- veys ought to have discovered by this time every geological fact and the complete solution of every geological problem within their field. No man would more generously welcome additional light upon such matters, even if the result should not altogether corroborate his former views. It is in emula- tion of his spirit, and without the slightest trace of a conten- tious inclination, that this paper is presented, in the hope that he may find opportunity to correct, however briefly, any error in its statements, logic or conclusions.

Lesley urgesf that the occurrence of No. III. (Hudson river) slates at Limeport, in the South Mountain region, is of great im- portance, as going to show that the erosion of that range began after the Coal age. He seems soon to have become somewhat less strongly inclined to that view; for a few months later he says, with less positiveness, that " the existence of patches of No. in. slates, overlying the limestones south of the gneiss mountains, . . . suggests that perhaps the entire series of Paleozoic formations, including the Coal-measures, extended continuously far to the south of their present outcrop-lines."! Do not these patches seem rather to prove merely that the ero- sion began after the deposition of No. III., quite in agreement with the indications of the topography and other circum- stances ?

It seems, indeed, possible that the topography of the southern region, the pebbles of the Pottsville Conglomerate, and perhaps

♦ Second Oeol. Surv. of Pcu, 1883, A A, p. xxi.

t Second Ged. Surv. ofPcu, D, vol. i.. p. xi., May, 1883.

J Second Oeol, Sw. of Pa. D, vol. ii., p. vii., October, 1888.

Southern Limit Op Pennsylvania Anthracite-Beds. 563

the geological structure to the south, may all indicate that the anthracite field never extended far to the southward of Sharp Mountain, and, at any rate, not south of the Lehigh river.

1. In his memoir on " Five Types of Topography,"* Lesley pointed out the striking difference in topographical form of five regions between Cincinnati and the sea, giving, in illustra- tion, a shaded topographical map of an area southward from Pennsylvania. His topographical map of Pennsylvania shows four of the five kinds of topography. The two northwestern types, of the " blue grass " country and the great Cumberland- AUeghany-Catskill, or Western Pennsylvania, plateau, and the southeastern tidewater type do not concern our present purpose. But the decided contrast between the two others (as seen in the map of eastern Pennsylvania herewith reproduced) may have a bearing upon our question. The southern one of these two includes the South Mountains in Adams county, and north- ward, and the Reading and Durham Hills ; and he describes it as the "Blue Ridge, Highland and Green Mountain belt, full of short, sharp ridges, in parallel order, but echelon ar- rangement, with irregular summit lines, rising into knobs and peaks from 8000 to near 7000 ft. above the sea." The great limestone valley seems to belong with this region, being, how- ever, by reason of the greater softness of its material, destitute of mountains. The space covered by the New Red in Bucks and Montgomery counties, and southwestward, appears to have been also a part of this region, and low for the same reason. The next topographical region northwestward, including the anthracite and other coal-fields, he calls " the belt of the Appa- lachians, composed of interminably long and narrow barrow- mountains, with level summits, seldom 1000 ft. in height, looped and goffered in an intricate and artificial style, with lens-shaped coves in the northern part; and on the other hand, in the Southern States, terminating in pairs of perfectly straight ridges, cut oft' short by faults."

The difference in topography of the two regions must clearly be occasioned by the unlike composition and unlike geological structure of the rock-beds, and by the unequal length of their exposure to erosion.

Trans. Am. Phil Society , yoL xiii., May, 1866, pp. 305-312.

564 Southern Limit Of Pennsylvania Anthkagite-Bbds.

The rocks of the more southeastern of the two regions are highly metamorphosed, and therefore, in general, very hard, firmly coherent and not easily eroded, compared with the rocks in the northwest The higher metamorphism appears to be the result of stronger and longer-continued horizontal com- pression, caused by the shrinking of the earth's crust in cool- ing. The compression has abundantly produced very, steep and overturned dips, and extremely numerous fractures, joints and fissures, promoting the easy circulation of water and the consequent progress of metamorphism, and, in many cases, the cementing of the particles together again by the strongest sili- ceous binding-material. The resulting hard rocks are eroded much more slowly than the less fully, or not at all, metamor- phosed rocks of the more western region, and a merely equal elevation of the hills of the hard materials would consequently indicate a longer exposure to erosion ; while greater elevation would be the natural result of the greater height to which the rock-folds have been raised by the stronger and longer, or more frequently repeated, compression. The generally shorter length of the ridges of the southeastern region may come partly from the fitct that the strong compression and fracturing has made it possible in more numerous places for the streams to cut across the ridges ; but the greater number of such crosscuts or gaps seems still more to be the result of a longer time during which the erosion has been going on. It appears, then, that the rocks of this southeastern region, compared with the next north- western one, have been longer undergoing compression, have been thereby more strongly compressed, and metamorphosed and hardened, and have repeatedly had the tops of their folds raised to greater elevation, and yet, in great part, reduced again by erosion to nearly about the same height as the north- western mountains, and to a somewhat more gently rounded shape ; so that the erosion must have taken a vastly longer time, and, consequently, the resulting forms have the appear- ance of greater age than those lying to the northwest It seems probable, therefore, that this region was already dry land, subject to erosion, while the later portions of the Paleozoic were still forming in the yet undisturbed northwestern region, of which the coal-fields are now a part

2. Again, the pebbles of the great Pottsville Conglomerate,

Southern Limit Op Pennsylvania Anthracite-Beds. 565

at the base of the Coal-measures, are so thoroughly rounded and waterworn as to make it evident that, hard as they are,

A Topographical Map of Eastern Pennsylvania,

Copied from the Map by J. P. Lesley in Report Z, on the Terminal Moraine, State

Geological Survey of Pennsylvania. Scale, 30 miles to an inch.

they must have been carried down streams for a great number of miles ; and therefore that the sea-shore must have been well to the north of their source. On the other hand, the rapid

566 Southern Limit Of Pennsylvania Anthracite-Beds.

diminution in size of the pebbles, northward and northwest- ward from the southern edge of the anthracite-field, and the quickly increased coarseness of the pebbles at the southern -edge, show that the shore of the Carboniferous sea, which laid them down, must have been near at hand and not far south of Sharp Mountain, the present southern boundary of the coal, the line of steep ridges close south of Pottsville and Mauch Chunk. As the diminution in size of the pebbles and in the thickness of the beds is radial, and not from one point alone, but several rather distant ones, the pebbles must have come into the sea at several points ; that is, must have come down rivers, with large accumulations near their mouths; and so could not, in any case, be the result of sea-shore erosion along numerous almost continuous cliiFs. The sand and shales also seem to have come from rivers. The pebbles, then, indicate that the original southern edge of the anthracite-region could not have been far south of Sharp Mountain, or, at any rate, not farther south than the lower part of the Lehigh valley.

3. One more fact may perhaps be urged as further evidence of the separate and unequal compression and folding, uplifting and erosion of the two regions. The (to say the least) not im- probably Paleozoic, Permian, age of the lower part of the Xew Red of Bucks and Montgomery counties has already been pointed out,* making beds there to appear contemporaneous Avith beds in West Virginia and the southwestern corner of Pennsylvania. These western beds have partaken of the fold- ing of the main Appalacliian region; but the Montgomery county ones have apparently never been disturbed, except by the gentle tilting, uplifting especially the southern border, that has taken place since the deposition of the New Red. It seems, therefore, as if this southeastern region had not been affected by folding at the time when, after the end of the Paleozoic, the anthracite region was strongly crumpled.

It appears probable, therefore, that the anthracite-region never could have extended far south of its present limits; that broad highlands originally bounded it on the south, supplying the pebbles, sand and shales that formed the Coal-measures; that these highlands emerged from the sea at some time before

Proc. Am, Phil. Society y voL xxxiii., p. 9 (Jan., 1894), and p. 215 (May, 1894) ; also, Finnl Report Second Geol. , of Pa., vol. iii., part ii., p. 2614.

The Vbins Of Boulder And Kalgoorlie. 567

the end of the Silurian epoch (say, after the deposition of No. in,, the Hudson river slates) ; that by strong and long-con- tinued compression they became highly metamorphosed, and had their rock-folds repeatedly raised higher ; and that they have been eroded for a much greater length of time than the anthracite-region and the rest of the main Appalachians.

The Veins of Boulder and Kalgoorlie.

By T. A. Rigkard, Denver.

(New Haven Meeting, October, 1902.)

Comparisons frequently do good service by affording a means of distinguishing the features which are essential from those which are merely accidental. When one reads of the lode-structure of a new, and perhaps distant, gold-field, there arises the desire to compare the characteristics mentioned with those of the regions with which one is already familiar. It will therefore be interesting to refer to the other districts with which Cripple Creek has been likened.

A. The Veins of Boulder County, Colorado.

Telluride-ores have been mined in Colorado since 1872. Previous to 1891, when Cripple Creek was discovered, the principal localities for such ores were the La Plata mountains and Boulder county. The former district is situated in the extreme southwestern part of the State. Boulder is about 90 miles due north of Cripple Creek, in that part of Colorado which was first opened up by the pioneers of 1859. The prevailing rock is the granite-gneiss of the Front range. The veins are notably associated with bands of chloritic gneiss, to which the French geological term of " protogine " was formerly applied. Dikes of quartz-porphyry and quartz-andesite occur at frequent intervals. In this respect Boulder resembles the adjacent well-known district of Gilpin county, but the ore- occurrence does not appear to be as intimately connected with the dikes as it undoubtedly is in Gilpin.

568 Thb Veins Of Boulder And Kalgoorlie.

The veins of Boulder appear to be bands of crushed rock accompanying lines of fracture which have been healed by the impregnation of ore. Fig. 1 will illustrate this characteristic type. The Enterprise is the principal lode of the El Dora dis- trict, on the western border of the county. The enclosing formation is granitoid-gneiss, traversed by belts of protogine and mica schist. In this instance a band, 8 inches thick, of clay, called " gouge " by the miners, and consisting of rock crushed to the condition of mud, follows the hanging-wall, which ap- pears as a distinct parting, separating the lode, A C, B D, from the enclosing country-rock. Next to the " gouge " comes a well- defined strip, 3 to 4 inches wide, of casing, which is made up of brecciated gneiss so laminated as to resemble a shale. The foot-wall is not very distinct, because the lode-matter merges insensibly into the country-rock. The ore, G H, appears in the form of dark threads of flinty quartz arranged in parallel lines amid the lode-stuff, which is essentially a granular matrix of partially-crushed granite-gneiss. The dark quartz carries finely-disseminated tellurides, chiefly petzite, which renders a width of 2 to 2J feet suflSlciently rich to yield an average of 2 ounces of gold per ton.

The Monongahela vein, shown in Fig. 2, occurs at Sunshine, in the central part of Boulder county, and resembles a score of similar lodes to be seen in the small mines which yield the bulk of gold from this interesting region, and are intermittently worked under lease by parties of experienced miners. Fig. 2 represents the eastern face of the 100-ft. level in the Monon- gahela workings as seen in April, 1897. The most prominent feature of the section is a dark band (A E, C H) of " horn- stone," or flinty quartz, which, on closer examination, is found to be composed of two separate streaks, A F-C Gr and F E-G H, in both of which specks of petzite are clearly distinguish- able. The upper portion, 3 inches wide, has numerous cavities, "vughs," lined with crystalline quartz and marcasite (white iron pyrites). The lower one, 2J inches wide, is more com- pact. Between the pay-streak (A E, C H) and the foot-wall (B D) there is a thickness of 7 inches of dark-gray quartz, through which patches and streaks of granular protogine are distributed. This band carries only traces of gold. It marks

The Veins Of Boulder And Kaloooblie.

T,j_,j_,j ..'V-r;.'.- -.I'lu.! ill ' I-, : Vi Mi-VV

Cale 1 Foot B

Granitoid Gneiss

0 TAJt IWl

til!

Cuing

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Crushed Rook

Quartz

Enterprise Vein. El Dora, Colo.

570 The Veins Of Boulder And Kalooorlie.

the transition between ore and country-rock. There is no dis- tinct hanging-wall. A narrow width of crushed country, A C, separates the pay-streak from the enclosing roclc The latter is traversed by several dark threads of flinty quartz, which may be regarded as feeders to the vein proper.

A little further west the pay-streak splits into two dark fila- ments of hornstone, separated by mottled quartz, and the lode becomes more valuable. This change is illustrated in Fig. 3. The band (E B, H D, in Fig. 2) of quartz containing inclusions of country-rock has thinned out, and finally disappeared. The double streak of ore (A F-C G and F E-G H in Fig. 2) has separated into two threads (E K and F L in Fig. 3) of banded hornstone, containing frequent cavities lined with quartz-crys- tals. Between these two threads there is a width of 6 inches of dark mottled hornstone, containing tellurides, and forming, therefore, rich ore. The small thickness, A C, of altered country to be seen on the hanging-wall side in Fig. 2 has be- come amplified in Fig. 3 to a 3-inch casing, C G, of crushed rock, and a further width, D H, of 6 inches of breccia, con- sisting of fragments of protogine cemented by brown quartz. The lode, which may be considered as extending from C to F and from G to L, is in protogine, and consists of that rock in variously altered condition, graduating from crushed country-rock, C G, to crushed rock impregnated with quartz, D H, and finally into a clean, dark, siliceous matrix, E F, K L, to which the term " hornstone can be fitly applied. The nature of the ore-occurrence can be further inferred from the gold-contents of the various portions of the lode. Thus, C G was poor, that is, it contained of an ounce so of gold per ton; H D carried 8 ounces of gold per ton; and the main streak, E F, K L, was worth, at the time of my visit, from f 2.50 to $5 per pound. The band H D becomes at times so impreg-

The miners, by evident confasion, called the dark, flinty veinstone horn- blende,'' instead of " hornstone/' and in the same manner they had converted vugh-hole" into bug- hole." Hornstone is good Anglo-Saxon, horn meaning resembling horn in being caUous or hard, as in 'homy-handed son of toil." The word chert " is nearly a mineralogical equivalent for hornstone. Chert is Irish, and originally meant " pebble."

THE VBINS OF BOULDER AND KALaOORLIE.

PiOA F .£ B

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w

Protogin*

)'

H D

Horns tone

Quartz

Monongahela Vein, Boulder Colo.

372 The Veins Of Boulder And Kalooorlie.

nated with dark quartz as to merge into the main streak of ore.

There is no selvage separating the ore-streak, E F, K L, from the enclosing rock. The seam of black hornstone, F L, is "frozen" to the foot-wall. This "hornstone" is a characteristic feature of the telluride-bearing streaks of Boulder county. It is essentially massive, compact silica, otherwise chalcedony or flinty quartz, darkened by the presence of finely disseminated particles of iron pyrites (chiefly marcasite) and the tellurides of gold and silver (either petzite or sylvanite). The richer portions are frequently characterized by the presence of prochlorite and roscoelite. The latter, which is a vanadium- mica, of a brownish-green color, is so notably associated with the valuable ores of Boulder that the miners have got into the way of considering it an essentially gold-bearing mineral. It occurs in the lodes of Kalgoorlie, in West Australia, and quite recently it has been found in the "Last Dollar," "Mary McKinney," and other mines in the Cripple Creek district*

B. The Lodes of Kalgoorlie, West Australia.

Kalgoorlie shares with Cripple Creek the honor of having brought tellurides to the front rank among the ores from which gold is won. The two districts have been likened, but erro- neously. Their geological unlikeness is their most interest- ing feature.

The veins occur in chloritic schist, the vein-stuff being essen- tially the same as the encasing country-rock, but more schistose in structure and more calcareous in composition. There has been much discussion among petrographers concerning the original character of the country enclosing the veins. f The alteration in the rock induced by extreme metamorphism has

See 'The Telluride-Ores of Cripple Creek and Kalgoorlie," Trans,, toL xzx., pp. 708-718. Fine specimens of roscoelite have been lately obtained from the Logan mine, near Crisman, in Boulder county. Boscoelite is named after Sir Henry K Boscoe, the celebrated chemist.

t Most of the evidence on this mooted point b well summarized by Mr. Geoige W. Card) in vol. vi., part i., "Records of the Geological Survey' of New South Wales/' 1898.

The Veins Op Boulder And Kalgoorlie.

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The Yeinb Of Boulder And Kalgoorlib.

rendered the conclusionfl of observers anything but unanimous. In the district itself the term " diorite " is loosely employed by the mine-managers to describe the prevailing formation, but microscopic sections exhibit a good deal of quartz and no horn-

Pig. 4 B

M "M v'M\M

p T A a. 1807

'N(JSchi$toe Rock

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A kALGOORLIE LODE

blende, and therefore prove that term to be inappropriate. Some feldspar can be detected. Titaniferous iron and mica are present. From sections which I secured in 1897, Prof. Judd, P.RS., concluded that the prevailing rock was a highly altered

The Vbins Of Bouldbr And Ealqoorlie. 575

quartz-andesite. As the formation appears underground it is a fine-grained foliated rock or schist with a silvery-green sheen and a fissile structure. It is rendered tough, and also soft, by reason of the calcite and sericite (or hydrous mica) which it carries.

A typical lode is illustrated in Fig. 4, which shows the face of the 270-ft. level in the Great Boulder Main Reef mine, on Oct. 18, 1897. It is a schistose band of rock with a well- defined line of parting, A F. This east wall," as it is termed, forms one boundary of the gold-bearing rock, that is, the lode, which has no defined limit on the west, but graduates into the country-rock on that side. There is an evident struggle between two systems of fracture ; the rock which is ore-bearing, A C, D F, is sheeted along lines which are nearly upright and paral- lel to the parting, A F, while the surrounding country has a contrary cleavage. The ore differs further from the surround- ing rock in being traversed by veinlets of calcite and granules of quartz arranged along the lines of fracture. Iron pyrites is also liberally scattered through this calcareous vein-stuff. Petzite and calaverite gave the lode here illustrated an average value of 8 J ounces of gold per ton.

The telluride-ores of Kalgoorlie appear sometimes to occur in long, overlapping lenses, as is illustrated in Fig. 5, which represents a series of ore-bodies cut at the third level of the Lake View Consols mine. It is said that the original owners of this now famous property followed the line of one of these long, torpedo-like lenses, and, not knowing the nature of the occurrence, their workings ran out into barren country so as to necessitate a cross-cut, which, unfortunately, was put out on the wrong side, with the final result that they concluded, as a Comishman would say, **that the lode had just naturally petered out." The ore tends to spread from one plane of folia- tion in the schist to the next one on the right, with the result that tle longer axis of each lens makes a small angle with the strike of the country, and the successive lenses follow one another m echelon, An occasional " wall " may be prominent

A military term descriptive of the movement of troops advancing in diagonal step-like succession.

Vol. Xxxiii.— 36

The Veins Of Boulder And Kalgoorlie.

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Thb Veins Of Boulder And Ealooorlib. 577

and the ore may follow it for a short distance, but it will leave it for another, equally well-marked. The " walls " or planes of parting do not limit the ore-channel ; some of them are within it, some extend beyond it, to become faint as they are followed into the surrounding country. In the space separating the lenses there are stringers and small seams of ore which serve as connecting threads of discovery. They act as " leaders,"* guiding the observant miner from one ore-body to another.

The description of veins in two districts so far apart on the map as Boulder in Colorado and Kalgoorlie in West Australia -emphasizes the diversity of structure characteristic of the lodes which carry gold. Both types of veins occupy fractures which have been healed by mineral solutions ; the Boulder type is dis- tinctly a segregation of amorphous quartz in the form of flint, with a cementing of the adjacent granite, which had been hrecciated at the time of the formation of the vein-fracture ; the Kalgoorlie type represents a sheeting of the schistose coun- try without any clean-cut Assuring and without a brecciation of the country, which, being more tough than a granular rock such as granite, and less fissile, exhibits the effects of strain in a system of parallel sympathetic partings, along which calcite and quartz have been deposited, and, with them, the tellurides of gold. In the Boulder type the tendency is to produce tab- ular ore-bodies known as " shoots " ; in the Kalgoorlie type the struggle between schistosity and sheeting, along a sheer zone, produces " lenses."

This is an Australian term which is worthy of adoption. Leader is from the A. & Ifedan, to gnide, just as lode is from lad, a path. A lode is the occurrence of ore which guides or leads a miner.

578 The Lodbs Of Cbipple Creek.

The Lodes of Cripple Creek.

BY T. A. RICKABD, DENVER, COLORADO. (New Haven MeetiBg, October, 1902.)

A. Introductory.

In a former paper* the writer has described the essential features of the general geology of the Cripple Creek region. In the present account it is intended to examine into the oc currence of the ores, the value of which has made this district the most important among existing American gold-fields. The production of Cripple Creek from its discovery, in 1891, to the close of 1901, has reached a valuation of fully $125,000,000* During the past year (1901) the output amounted to $17,285,- 470. In 1900 it was $18,174,681.

The first discoveries, which led to the development of the district, were made in the spring of 1891, but it was not until 1893 that vigorous work was commenced. A great im- petus was then given to the exploration for gold on account of the sudden drop in the marke1>price of silver, caused by the closing of the Indian mints in the summer of that year* This induced an energetic population from the older silver- mining camps of Colorado to go to the new gold-field, which was then beginning to attract attention. Prospecting, at first, was hindered by the comparative absence of outcrops, due to the fact that the surface of the hills is covered with a consid- erable thickness of shattered rock, resulting from the action of frost at a high altitude ; but so much indiscriminate digging was done that a number of rich veins were uncovered, and this stimulated the search for others. The advanced condition of the mining industry of Colorado offered unusual facilities for exploration and reduction ; progress was therefore rapid, with the result that the district soon achieved great prominence.

*'The Cripple Creek Volcano,'* IVan*., XXX., 367-403. It is proper that refer- ence should also be made to the more authoritative monograph on the Geology and Mining Industries of the Cripple Creek District,'* by Whitman Cross and B. A. F. Penrose, Jr., XL 8, 0, 51, Uth Ann. BepL, Part 2 (1896), pp. 1-209.

The Lodbs Of Cripple Creek. 579

B. Geological Character of the District.

The geological environment of the gold-bearing veins can be outlined briefly. The district occupies the ground-floor of a volcano, the superstructure of which has been removed by ero- sion. This basal wreck of material erupted during the Tertiary period now survives as a complex of volcanic rocks, filling the hollows and occupying the plug of a basin which is surrounded by the granite of Pike's Peak. The volcanic area of Cripple Creek occupies about nine square miles, and consists, for the most part, of breccia, in which andesite predominates. Pene- trating the breccia in every direction are numerous dikes, composed of various rocks, those of basalt and phonolite being the most notable, on account of their close association with the occurrence of ore.

The mine-workings have reached a maximum depth of 1400 ft. Added depth appears to have affected the persistence of the ore to the same extent as experience elsewhere would lead one to expect. The veins situated near the edge of the breccia have in several cases been followed downward in their penetra- tion of the underlying granite, and it has been demonstrated that some of the ore-bodies have continued from the upper into the lower geological horizon. The distribution of these ore-bodies offers the same perplexing problems as in other gold-fields. Ex- tensive developments, due to very successful mining, have, how- ever, afforded a great deal of interesting evidence, the consid- eration of which may contribute toward the better understand- ing of the economic geology of the district.

The mines exhibit examples of a great diversity of lode- structure. This diversity is mainly traceable to the complexity of the enclosing rocks. The variations in ore-occurrence due to this fact explain the vicissitudes which marked the early history of the district, and the recognition of them should pro- mote the success of future exploratory work.

During the past five years, while examining a dozen of the principal mines, the writer has gathered many examples of vein-structure which are herewith submitted as testimony bear- ing upon the ever-fascinating problem of ore-occurrence. As a poor witness may sometimes furnish a good lawyer with an illuminating bit of evidence, so the writer hopes that this testi- mony may be of service to the geological philosophers who are engaged in the study of ore-deposits.

90 The Lodes Of Cripple Creek.

without any lens. Thus I possess a piece of ore characterized by large crystals of pinkish feldspar (or orthoclase) and a little silvery mica (muscovite) held together apparently in a cavern- ous mass of quartz, through which bright specks of calaverite are scattered. The quartz contains spots of green, earthy <3hlorite and a very few minute cubes of fluorite. White quartz, as a distinct veinstone, does not characterize these lodes to the extent usually observable in gold-lodes elsewhere, although secondary quartz is everywhere found penetrating the altered veinstone. Pyrite is also a constant companion of the gold- bearing tellurides, and fluorite is readily to be seen save where, near the surface, it has been decomposed. The occurrence of flu- orite has suggested many theories, but the fact that it forms an original constituent of the granite of the Pike's Peak region and the prevalence, in the same neighborhood, of such fluorine- bearing minerals as cryolite and topaz,* renders it dangerous to draw inferences connecting it with the ore-forming agencies. There is the appearance of probability about the idea that the secondary fluorite of the lodes was derived by the circulating waters from the granite of a lower horizon, and it may be men- tioned that Fouque showed that hydrofluoric acid in a liquid state has a notable effect on silica and silicates by first de- composing the uncrystallized silicates, or glasses, and then act- ing similarly on feldspars and other acid silicates, then on quartz, and lastly upon the basic silicates. Whether hydroflu- oric vapor acts similarly is an open question. Under such cir- oumstances, quartz might be attacked before feldspar.

F. Veins in Andbsitb and Andbsitb Breccia.

The andesite of Cripple Creek is usually an augite-mica- andesite. It is distinguished by having apatite as one of its constituent minerals. Although this andesite forms the prin- cipal element of the breccia, the latter is notably irregular in its composition. Phonolite is sometimes locally predominant, and near the edge of the volcanic area the breccia contains a large proportion of fragments of granite. The breccia, since

Florissant and the Pike's Peak region generally are celebrated for specimens of topaz. W. S. Stratton, the discoverer and former owner of the Independence mine, was prospecting for cryolite, as a source of aluminum, just previous to his first trip to Cripple Creek.

The Lodes Of Cripple Creek. 581

C. A Type of Lode-Structure.

A small section of a single vein will sometimes typify the lode-structure of an entire region. Such I believe to be the case in the occurrence which is illustrated in Fig. 1. It repre- sents the vertical section of a portion of the Independence vein as it appeared just south of the station at the second level from the No. 1 shaft. The scale indicates that the space covered is about 10 ft. high by 16 ft. wide. The country-rock is the pink, coarsely crystalline Pike's Peak granite ; the vein, A K, L C, appears as a band of iron-stained, decomposed granite along- side of a phonolite dike, A B, C D, which throws out a nearly horizontal tongue, E F, G H, into the rock on the west. This oflshoot from the dike is crossed by the vein, and it affects the distribution of the ore. Thus, while the decom- posed gold-bearing granite, constituting the lode, is about 1-1 J ft. wide both above and below this intrusion of phonolite, it is broken up at the place of crossing into a few stringers cutting through the phonolite ; so that, while the lode maintains its continuity, it does so with difficulty. An important feature of the section is the evidence obtainable as to the relative age of the phonolite and the joint-planes in the granite. The pho- nolite is, of course, younger than the granite which it pene- trates. But this is not all ; it is also apparent that the joints in the granite are more recent than the dike. Observe how the joint-planes, E F and G H, cut through the protruding sinuosi- ties of the outer edge of the phonolite. It remains to add that there is a distinct division, but no selvage, between the hang- ing-wall, A C, of the vein and the dike which it accompanies, while on the other side, K L, the vein is not marked by any clear line, but graduates, by the lessening of the evidences of decomposition, into the outer granite. The east wall, B D, of the dike exhibits a marked selvage, and it is also accompanied by traces of ore. On the joint-plane, G H, which is nearly horizontal, there is a slight, but evident, selvage.

The story told by this section is that the phonolite penetrated the granite ; that, subsequently, a line of fracture was estab- lished alongside the phonolite ; that this afforded a passage-way for ore-bearing solutions ; that the impregnation of ore was less where the solutions passed through the protruding tongue of phonolite, because there, the rock being closer-grained and

Thb Lodbs Of Cripple Creek.

Fig. 7 A e

5"

I 5C4La

, 1 Foot

AN0£5IT£ BflECCIA

IpHVORlTE SELVAoe

The Lodes Of Cripple Creek. 583

very probable that the jointing of the granite and the fractur- ing now identified with the lode were contemporaneous, both being the result of mechanical stresses connected with the arth-movements which followed the last stages of volcanic activity in the district.

D. General Characteristics of the Veins.

The foregoing example will serve as a text for a preliminary statement. The lodes of Cripple Creek are essentially lines of fracture accompanied by a variable width of rock, the constitu- ents of which have undergone replacement by fluorite, quartz, pyrite and other gangue, together with gold-bearing tellurides. The width and distribution of the ore depends upon the extent and character of the fracturing; the study of the latter is there- fore of vital importance to the miner. Owing to the number of volcanic rocks occurring in the district, the veins differ greatly in appearance ; but this difference is traceable to diverse structural conditions rather than to diversity of origin. In all the lodes which I have examined, the ore is essentially rock in place, however much altered ; the lodes are to be regarded as bands of replacement, rather than the filling of open fissures or crevices; nor is there any departure from the rule that the lodes were formed during a late period in geological history, for the ore is, in every case, as far as I know, subsequetit to the intrusion of the eruptives which penetrate the breccia, itself of late Eocene or early Miocene age. While these eruptives cut across each other and thereby evidence their relative succession in geological time, they do not appear to cut across the ore- veins, which, on the contrary, pursue their course amid varying petrographic conditions, unchecked but not unchanging, for to the changes due to this variable rock-environment we owe the extremely interesting variations in ore-occurrence.

The lodes have originated from lines of fracture formed sub- sequent to all the members of that volcanic complex which con- stitutes the gold-field. These fractures are the outward mani- festation of lines of weakness, or of such comparative weakness as is the equivalent of least resistance ; therefore, it is not at all surprising that the veins frequently follow the planes of contact between rocks which are unlike in hardness, and especially the very close-grained eruptives when these traverse the coarse- i;extured breccia.

The Lodbs Of Cripple Creek.

la.'

4 .

.o

p .'

ATi

fc''/-J BRECCIA

/

Fracture

#

Ore.

IMPREGNATION ALONG fARALLtLTRACTURCS

iron* and the liberation of the gold in a brown amorphous condition, resembling yellow paint which has become tarnished.

This alteration product has a definite chemical composition, as has been de- termined by F. C. Knight See "A Suspected New Mineral from Cripple Creek," Proceedings of the Colorado Scientific Society vol. v., pp. 66-71, October 1, 1894. Mr. Knight's analysis gave a percentage of Fe,Os, 32.72 ; TeO,, 65.45 ; and HgO, 1.83. The physical characteristics ascertained were, a light-brown color, a dull luster, a brilliant and uneven fracture, a hardness between 3 and 4, and a bright yellow streak.

Thb Lodes Of Cripple Creek. 585

For this reason phonolite is closely related to the occurrence of ore, — so much so, indeed, as to be often confounded with the origin of that ore. The later dikes of basalt are also notably connected with important lodes. It is possible to generalize further and state that the dikes, especially the very numerous dikes of phonolite, spread outward toward the edges of the volcanic area, and, as a consequence, the strike of the principal veins also has a radiated distribution. The latter are dependent in their strike upon structural relations coincident with the dike system, the arrangement of which points to the approxi- mate position of the volcanic vent, or vents, supposed to be situated somewhere in the central portion of the district.

Prom these preliminary considerations it is evident that the study of the district, from the point of view of the miner, re-- solves itself into the endeavor to understand the structural re lations of the ore-deposits as affected by the fracturing of the rocks. Questions of origin may be of greater interest, because they appeal to the scientific imagination, but they do not have any direct bearing on the economics of mining. To those who conduct mining operations it is not so much a question of " Where did the gold come from ?" as " What are the condi- tions which determine the distribution of it among the rocks now penetrated by mine-workings?" Therefore, the patient deciphering of complicated systems of fracture will be of more immediate help to the miner than the broad philosophic con- siderations which render the science of ore-deposits so fascinat- ing to all of those who are interested, even indirectly, in mining.

Before discussing the matter any further it will be well to pass in review more of the evidence afforded by the examina- tion of the lodes as seen underground. For the sake of con- venience, it is considered advisable to divide the lodes accord- ing to their encasing rock, which is also their matrix.

E. Lodes in Granite. The granite which surrounds, and partially underlies, the breccia of the volcanic area of Cripple Creek forms a part of the mass of Pike's Peak, the great mountain which overlooks the district from the northeast, and has given its name to the rock. The country near the mines, however, is not the same as

586 The Lodes Of Cripple Crbek.

the Pike's Peak granite, orthoclase replacing, to a large extent, the microcline of the typical rock. The Cripple Creek granite may be described as a pink, rather coarsely crystalline rock, the most prominent constituents of which are biotite (black mica) and orthoclase (feldspar), the latter occurring in large, tabular crystals. The color of the rock is due to that of the orthoclase which has been stained red by iron oxide. Flu- orite occurs sparingly, but it is interesting on account of its association with the ores of the district. In different portions of the district the granite presents variations, the most im- portant of which is a very fine-grained rock that, in the form of dikes, penetrates the coarser variety, and is evidently of more recent date than the basal rock of the region.*

Fig. 2 illustrates a gold-bearing lode in granite. It repre- sents the heading of the 160-ft. level in the Hallett. and Ham- burg claims, near Victor, as seen in April, 1897. The ore ap- pears as an ill-defined band, B B, about 1 ft. wide, which is wholly in granite, but at the same time is only 2 ft. distant from a, large phonolite dike, A A. The alteration of the granite, which marks the course of the ore, follows a series of short, overlapping seams, parallel to the line of the dike, and also ex- tends into the surrounding rock along the cross-joints, C C. The width of 2 ft. of granite which separates the vein from the dike exhibits partial alteration along the seams, D D, and car- ries a feeble scattering of ore. The granite under the vein is fresh and unaltered. In the ore-bearing rock the mica is nota- bly absent, the granite is honeycombed by decomposition, and of the two constituent feldspars, oligoclase and orthoclase, the former is kaolinized. Iron pyrite bespatters the gold- bearing portion, and, by its partial oxidation, stains it dark red.

Fig. 3 exhibits the Independence lode in the Washington -claim, which is a portion of the Stratton's Independence prop- erty. The lode, which farther north traverses the breccia and is closely associated with a phonolite dike, is seen here as a band of decomposed granite subdivided equally by a central thread of quartz. The ore is essentially granite. The por- tion A C, D F, is 4 ft. wide, and carries a little over 3 ounces

This is discussed by Whitman Cross on page 23 of the ''Geology and Mining Industries of the Cripple Creek District, Colorado.

THE LODES OF CRIPPLE CREEK. Fio. 6.

Anaconda Ix)de as seen in an Cut in 1897.

588 The Lodes Of Cripple Creek.

of gold per ton. The width of 4 ft. which carries gold, and is therefore ore, has no parting or wall separating it from the outer rock, which is granite, and is regarded as waste, but i& distinguished from the latter in many ways. The outer granite is fresh and unaltered, exhibiting with great clearness its con- stituent minerals, reddish quartz, black biotite-raica and pink orthoclase-feldspar. The inner gold-bearing rock is much altered by decomposition and replacement; the orthoclase- alone appears to have survived the general destruction; the mica has been removed, and, in its stead, chlorite can be seen in green patches ; the original crystalline quartz is largely gone, and the presence of purple fluorite suggests that hydro- fluoric acid may have been a primary agent in that removal ; secondary hydrous quartz fills many of the interstices between the crystalline constituents of the rock;* in iron-stained cavi- ties free gold can be seen by the aid of a pocket-lens, and the gold is observed to have the dark, lusterless appearance which characterizes it when derived from the oxidation of tellurides* The entire width of this gold-bearing decomposed granite is heavily iron-stained by the oxides resulting from the disintegra- tion of the small crystals of iron pyrites, which can still be seen, in an unaltered condition, scattered throughout the same lode, at lower levels. In the center of the band of ore there is a distinct parting, B E, which is separated from a persistent thread of white quartz, only about a quarter of an inch in , by a slight selvage of red clay. At a distance, the lode appears as a distinct broad band of iron-stained granite, and it is only by closer examination that the boundaries of it are seen to consist, not of " walls " or of any such evident demarkation,. but merely of a transition from decomposed into undecom- posed granite.

The Independence vein is illustrated again in Fig. 4, which was obtained on the same level as Fig. 3, but 300 ft. farther to the north, where the vein lies against a phonolite dike, A B—

This description is founded on the examination of hand-specimens by the aid of a pocket-lens. To those who desire to go into the matter further, there is the detailed description of Mr. Lindgren, together with microscopic sections of this very ore (made from specimens which I gave to Mr. Emmons in 1900), to be found in that most important contribution entitled '' Metasomatic Processes in Fissure- Veins," by Waldemar Lindgren, Trans. y xxx., 578-692, especially page 655.

The Lodes Of Cripple Greek. 589

D E. The thread of quartz, shown at B E in Fig, 3, is to be seen again as a larger, but less regular seam, B E, in Fig. 4. In this case it is characterized by cavities, or " vughs," as the miners call them, which gave evidence,* at the time they were first encountered by the workings, that they had served a& water-holes along a line qf underground circulation. This may be considered as marking the line of the original fracture which determined the course of the lode. In Fig. 3 it was in the center of the ore ; in Fig. 4 it marks the western limit, and separates the ore-bearing granite from the phonolite. The lat- ter is 20 inches wide, and regular. The lode consists, as in the preceding instance, of highly-altered granite, which is richest along the contact with the dike, and shades off eastward (from B E toward C F) along an irregular wavy line, C F, which in no case has any of the characteristics of a " wall " or defined separation between what is gold-bearing ore and what is barren rock.

These characteristics are repeated in other sections which I have sketched underground. The lodes in the granite are fre- quently remarkable for absence of definition, as was instanced in Fig. 4, this being due to the evenly granular texture of the rock. Within the zone of oxidation the boundaries of a gran- ite lode are made manifest by the red-brown stain, due to the decomposition of iron pyrites ; but below the zone of surface- waters it becomes difficult to distinguish country- rock from ore without frequent assays. When the granite has undergone impregnation it is usually porous, by reason of the removal of the microcline and some of the quartz of the original rock. Whatever biotite, hornblende and epidote it contained are ab- sent from the ore, and their decomposition-product, chlorite, is in evidence. Microscopic sectionsf indicate that secondary valencianite (a form of orthoclase feldspar) and sericite (hy- drous mica) have been formed, and that iron pyrites, fluorite and the tellurides have been deposited within the cavities pro- duced by the removal of parts of the granite, and also along the cracks which traverse the rock. Occasional specimens, ob- tained from the stopes, exhibit these changes on a scale visible

By containing water and by being lined with slime.

t See Lindgren, Trans., xzx., 656, and Genesis of OreDeposiUj p. 576.

590 The Lodes Of Cripple Creek.

without any lens. Thus I possess a piece of ore characterized hy large crystals of pinkish feldspar (or orthoclase) and a little silvery mica (muscovite) held together apparently in a cavern- ous mass of quartz, through which bright specks of calaverite are scattered. The quartz contains spots of green, earthy <5hlorite and a very few minute cubes of fluorite. White quartz, AS a distinct veinstone, does not characterize these lodes to the extent usually observable in gold-lodes elsewhere, although secondary quartz is everywhere found penetrating the altered veinstone. Pyrite is also a constant companion of the gold- bearing tellurides, and fluorite is readily to be seen save where, near the surface, it has been decomposed. The occurrence of flu- orite has suggested many theories, but the fact that it forms an original constituent of the granite of the Pike's Peak region and the prevalence, in the same neighborhood, of such fluorine- bearing minerals as cryolite and topaz,* renders it dangerous to draw inferences connecting it with the ore-forming agencies. There is the appearance of probability about the idea that the secondary fluorite of the lodes was derived by the circulating waters from the granite of a lower horizon, and it may be men- tioned that Fouque showed that hydrofluoric acid in a liquid state has a notable effect on silica and silicates by first de- composing the uncrystallized silicates, or glasses, and then act- ing similarly on feldspars and other acid silicates, then on quartz, and lastly upon the basic silicates. Whether hydroflu- oric vapor acts similarly is an open question. Under such cir- cumstances, quartz might be attacked before feldspar.

F. Veins in Andesite and Andbsitb Breccia.

The andesite of Cripple Creek is usually an augite-mica- andesite. It is distinguished by having apatite as one of its constituent minerals. Although this andesite forms the prin- <;ipal element of the breccia, the latter is notably irregular in its composition. Phonolite is sometimes locally predominant, and near the edge of the volcanic area the breccia contains a large proportion of fragments of granite. The breccia, since

Florissant and the Pike's Peak region generally are celebrated for specimens of topaz. W. S. Stratton, the discoverer and former owner of the Independence mine, was prospecting for cryolite, as a source of aluminum, just previous to his first trip to Cripple Creek.

The Lodes Of Cripple Creek. 591

it was laid down as a product of violently explosive volcanic eruption, has become decomposed and cemented. According to Whitman Cross, the decomposition has led to the " total de- struction of the dark silicates," such as the augite, hornblende and biotite present in the original fragments, and in the re- moval, by leaching, of the compounds resulting from this de- composition.* The result has been to change the breccia from dark crumbling material into a bleached compact mass which, in process of time, by reason of pressure and waters contain- ing kaolin, silica and other cementing substances, has become consolidated into a hard, massive rock. In the vicinity of the lodes the effects of siliceous solutions are rendered apparent by the impregnation of quartz to such a degree as to obscure the original fragmentary nature of the rock and make the finer-grained breccia, or tuff, resemble phonolite in texture And appearance. The variations in the andesite and andesite- breccia are responsible for corresponding changes of lode- structure, as will be presently illustrated.

Fig. 6 is a photograph of the Anaconda lode, as seen in an open-cut, in July, 1897. The lode at this place forms a part of an andesite dike traversing the breccia. The dike exhibits a multiplication of fractures parallel to its walls, and along these lines of cleavage there occur seams of quartz and fluorite car- rying tellurides.t In the surface-workings, liie gold liberated from the tellurides occurred pseudomorphic after sylvanite, distributed in yellow patches amid purple fluorite, affording specimens of great beauty.

When, as rarely happens at Cripple Creek, the lode consists of massive ore notably separated from its encasing rock, it will be found that such definition of structure is due to the presence of fluorite and secondary quartz which have so filled up the interstices of the decomposed breccia as quite to obscure its original character. Fig. 7 represents the main lode of the Gold Bang mine, in Poverty Qulch. At the time the drawing

"Geology and Mining Industries of the Cripple Creek District, Colorado," page 52.

t The general characteristics of the ores of this district have been separately described. " The Telluride Ores of Cripple Creek and Kalgoorlie,*' by T. A. Rickard, ,, xxx., 708-718.

t See " Farther Notes on Cripple Creek Ores/' by Richard Pearce, Proe, Ooh. Sdeniific Society vol. v., pp. 11-16.

THE LODBS OF CRIPPLE CREEK. Fig. 7

S

t SCAL& , 1 FOOT

0 jy

An0£5It£ Breccia

. The Lodes Of Cripple Greek. 593

was made the stopes had a maximum width of 12 to 18 ft. The rock, owing to partial oxidation, seemed, at first glance, to be structureless and homogeneous, but on closer investigation, prompted by contradictory assays, it was found that in the middle of the section afforded by the stopes, which were (for- tunately for the purpose of observation) unencumbered with timbering, there was to be seen a compact dark band, A B- C D, from which small seams, E E, went out, almost at right angles, into the surrounding breccia. This band, which was the vein proper, also consisted of breccia, but so impregnated with purple fluorite and so interpenetrated by secondary quartz as to hide the fact. Throughout the massive vein-stuff fine iron pyrites was scattered, and with the pyrite were crystals of calaverite, rendering it very rich. At intervals, small cavities lined with crystalline quartz occurred, as is indicated at H, H, in Fig. 7. In these cavities occurred crystals of native gold pseudomorphic after calaverite. Owing to their dull, rusty exterior, they looked like bits of rotten wood, and it required close observation, especially underground, to detect them. When scratched, they gave instant testimony of their precious nature. Minute stringers of ore, rendered noticeable by the color of the fluorite, followed the cross-fractures or joints in the surrounding breccia, and, aa delicate threads, accompanied the central vein, A B-C D, the boundaries of which were further marked by a granular selvage along A C.

Fig. 8 is very characteristic of Cripple Creek veins in brec- cia. It represents the breast of a level following one of the branches of the Bobtail lode, in the Independence mine, on Battle mountain. The Bobtail lode itself is similar, but its true structure is less evident on account of a more diffused im- pregnation of ore. The oxidation of the pyrite accompanying gold-bearing tellurides marks the course of the ore-streaks, A B and C D. They look, at a distance, like mere stains ; but closer observation discloses the fact that they are partings along the lines of fracture in the breccia, each of which forms the center of a narrow band of oxidized pyrite and very minute, bright specks of calaverite. The latter is seen, under the mag- nifying glass, to be in process of decomposition, the oxidation of the tellurium of the telluride in the presence of decompos- ing pyrite having resulted in the formation of the tellurite of VOL. xxxin.— 36

The Lodbs Of Cripple Creek.

IMPREGNATION ALONG fARALL€L.rRACTaReS

iron* and the liberation of the gold in a brown amorphous condition, resembling yellow paint which has become tarnished.

This alteration product has a definite chemical composition, as has been de- termined by F. C. Knight See "A Suspected New Mineral from Cripple Creek," Proceedings of the Colorado Scientific Society, vol. ▼., pp. 66-71, October 1, 1894. Mr. Knight's analysis gave a percentage of FejO,, 32.72; TeO,, 65.45 ; and H,0, 1.83. The physical characteristics ascertained were, a light-brown color, a dull luster, a brilliant and uneven fracture, a hardness between 3 and 4, and a bright yellow streak.

The Lodes Of Cripple Greek. 595

The tributary streaks, along the cross-joints of the breccia, are also gold-bearing for a short distance away from A B and C D.

Such parallel partings as have been shown in Fig. 8 are sometimes so multiplied as to become zones of sheeting. An -example is exhibited in Fig. 9, which represents a lode in the Moon- Anchor mine. This type of ore-occurrence is thoroughly characteristic of the mines in that part of the district known as Gold Hill. The breccia is fine-grained. The partings are -about a quarter of an inch apart. They are followed by minute seams of red, gritty clay in which the tellurides can be distin- guished. The individual seams are united by transverse im- pregnations which collectively make a pocket or small body of ore, in which it is not unusual to encounter patches consisting of an almost solid aggregate of crystalline calaverite and kren- nerite.* This sheeted structure dies out into the enclosing country-rock by the process of a gradual widening of the space intervening between each successive parting.

Fig. 10 represents the Emerson vein at the fourth level of the Independence mine. Here, also, the country is andesite- breccia. A central thread, B E, of fluorite and quartz, is fol- lowed by a band, A C-D F, about 3 ft. in width, of decomposed rock, which is gold-bearing, and therefore regarded as a lode. This lode appears as a band of bleached rock amid the dark- gray breccia. It is marked by thin veinlets of quartz, and is sparingly honeycombed with small, spongy cavities, containing iron pyrites and fluorite. The ore has no defined boundaries, but in the space from A to C and D to F it averages 2J oz. of gold per ton.

The breccia and tuflF exhibit the eftects of the thermal waters which have penetrated them during the quiescent stage of the volcano. Kaolinization of the feldspars was the most evident result; the dark silicates also are entirely gone, and are re- placed by white mica.t During the subsequent period, when the ore-deposits were in process of formation, these decomposed fragmentary rocks, already partially cemented by their kaolini- zation, became further consolidated by siliceous solutions, so as

Krennerite is a telluride of gold, approximating calarerite as regards compo- sition, but differing from the latter in possessing a perfect cleavage. It was named after Professor J. A. Krenner, of Buda-Pesth.

t As observed both by Lindgren and by Cross.

The Lodes Op Cripple Creek.

to be changed into a compact hard rock. Underground, near the veins, by reason of the bleaching, due to decomposition, the

Fw. 9.

'IShE: ./FOOT

AMDCtlTC ftftcccM

Ore Along Sheeted Zone

breccia has the mottled look which the miners recognize by the term " porphyry." As in the case of the granite, secondary minerals are readily found wherever the breccia has been

The Lodes Of Cripple Creek. 597

changed into ore and the ground-mass of the rock is seen to have undergone substitution by fluorite and pyrite. The former enters into the ground-mass so thoroughly, sometimes, as to make it a purple rock spotted with bits of bleached ande- ite. It is a feature of the breccia that the ground-mass of it has undergone mineralization more extensively than the rock- fragments which it coYitains, — an observation which illustrates the selective action of the circulating waters. As a conse- quence, even when it is changed into ore, the included pieces of andesite are conspicuous, and are often edged with the ore- forming minerals, such as pyrite, fluorite and the tellurides. However, the most important change which the breccia has undergone, in the vicinity of the lode-fractures, is its silicifica- tion by impregnation with quartz. This is not so apparent as would be imagined, because it does not occur in the form of bands of white quartz or dark hornstone, but rather as an ill- defined width following the dominant lines of fracture. For this reason the ore is often harder than the country-rock, and the workings on the lode require less timbering than the cross-cuts.

G. Veins in Phonolite. Phonolite is in many respects the most characteristic rock of the gold-field because of the comparative rarity, elsewhere, of this species of eruptive, and its marked association with the occurrence of ore in this particular mining district. The essen- tial constituents of phonolite are nepheline and that glassy variety of feldspar termed sanidine. Sodalite, nosean, and a variety of augite called aegirine, are common to the Cripple Oreek phonolite, which, typically, appears as a dull greenish- gray, dense, very hard rock, distinguished from the other erup- tives in the district by a schistose structure* that gives it a sherd-like fracture. In the vicinity of the lodes the greenish tint (due to augite and allied minerals) has been obliterated by bleaching, and a speckled or porphyritic appearance is given by white spots of decomposed nosean.f

Due, according to Whitman Cross, to the fluidal arrangement of the tabular feldspars. Op, eU,, p. 33.

t This is especially a characteristic of the so-called Independence dike, as seen at the third and fourth levels of that mine. Professor Judd, F.B.S., from speci- mens which I sent to him, labelled this rock distinctively a "nosean phonolite.'' For further discussion of the varieties of phonolite occurring in the region, the reader may refer to Dr. Whitman Cross's interesting descriptions in the " Geol- ogy and Mining Industries of the Cripple Creek District, Colorado,'' pp. 34 to 41.

The Lodes Of Cripple Creek.

Phouolite is normally a fine-grained close-textured rock, and for this reason the alteration which it has undergone, wherever it has been in the passage-way of the ore-depositing agencies,

PiG.T*

IMPfe6NATI0N FOLLOVilliO'A SlU&LE FRfCTWE..

is rendered more striking. The Independence dike, which ac- companies a very rich vein, has been so corroded by the solu- tions as to be a spongy-looking porphyritic rock, especially

Thb Lodes Of Cripple Creek. 599

wherever it happens to have lain in the path of the ore-bearing solutions which found a way along the vein-fracture. Where not thus altered by impregnation, the phonolite is often so cleaved by cracks parallel to its walls, and to those of the accompany- ing lode, as to resemble a shale. At such places it is usually mineralized by the occurrence of pyrite and tellurides along the faces of the cracks.

The phonolite occurs not only within the central mass of breccia, but also outside the immediate boundaries of the vol- canic area, penetrating the granite in dikes and in large, irreg- ular, intrusive masses, one of which forms Mt. Pisgah, so cele- brated in connection with the early history of the Pike's Peak region.*

In the distribution of ore, phonolite plays an important part, as the sequel will show. It has already appeared in Fig. 4, but not in so direct a relation as, for instance, in Figs. 5 and 11, now to be described.

Fig. 11 is especially interesting when taken in connection with Figs. 8, 4 and 5, because it represents the same vein amid a different geological environment. The dike in Fig. 4 is the same as the one, B C-E F, in this drawing, while the body of phonolite to the left is a tongue from a large mass of brecciat-ed phonolite occurring in this part of the mine. The feature to which it is desired to draw attention is the distribution of ore at this point. The dike, B C-E F, is the traversing breccia. The main ore-streak consists of the width of breccia, 26 inches across, separating the phonolite at B E from that at A D. There is some ore also in the phonolite dike, especially along C F, where it is so shattered as to resemble a shale. Threads of ore also occur along the other cleavage-planes in the phonolite, and are (observe G G) widely distributed through the breccia to the easty so as to form a large mass of comparatively low- grade ore. By way of summary, it may be said that the ore is scattered through the breccia and is concentrated near the edge of the phonolite, occurring in the body of the latter only where it happens to be shattered.

In Fig. 5 the Independence vein is again illustrated, as it

The Mt. Pisgah story is told in my earlier paper, "The Cripple Creek Gold- field," Proeeedings of the InstUution of Mining and MeiaUurgy London, voL yiii.', pp. 50-51.

The Lodes Of Cripple Creek.

appeared in the raise between the 800-ft. and the 700-ft. levels, in June, 1899. The same dike of phonolite, E P-G H, having

t:

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/

—

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gg BfeCClA 0R€ fg] PHONOLITE

here a width of from 18 to 20 inches, occupies the center of the band of gold-bearing granite, A C-B D, which is the lode.

The Lodes Of Cripple Creek. 601

When sampling the ore, previous to shipment, it was found that the dike only yielded fines or " screenings," indicating that the fine particles, which came off the cleavage-planes, carried whatever gold there was in the phonolite. In the case of the granite, on the contrary, the bulk-ore was the best. The lode extends from A to C ; the left-hand portion is about 2 ft. wide, is traversed by streaks of fluorite, and is richest . along the contact with the dike. This is also true of the right-hand por- tion, which is 2 J ft. wide and similar in character. The richest parts follow the dark streaks composed of purple fluorite asso- ciated with iron pyrites, accompanied by the tellurides, sylvan- ite and calaverite.* The walls, A A and B B, are clean and defined, with a slight selvage. The outer rock is a fresh pink granite, the inner lode-granite being kaolinized and otherwise altered.

Pig. 12 was obtained at the fourth level of the Independence mine, at a place where a part of the Bobtail vein, in its north- ward course, penetrates a mass of phonolite, which, apparently, is only a local enlargement of another dike crossing the breccia at a slight angle with the vein. The main streak of ore, even at this point, is in breccia, so that it is only the enlargement of the Bobtail lode, 5 to 6 ft. wide, which is considered to reach into the phonolite. The planes of fracture are well-marked. Where the ore occurs, the rock is sheeted along lines which are parallel to the lode, and accompanying these ftactures there are found small threads of extremely rich material. That marked A A is the largest ; it is only from a quarter to half an inch thick, and consists of little crystals of iron pyrites, which, by reason of their partial oxidation, give the ore-streak a dull-red color, and render very distinct its passage through the light-gray rock. Tellurides accompany the pyrite, and are the cause of the high gold-contents of the ore. The other €treaks are similar, though smaller. The surrounding phono- lite is peppered over with minute cubes of purple fluorite, which darken it. Many of the planes of fracture are lined with the same material. The whole mass, from A A, and across C C, for a width of 6 ft., assayed 3 to 4 ounces of gold per ton.

And especially a massive granular telluride, found, hy Mr. W. E. Ford, to be a variety which, as regards composition, is intermediate between calaverite and sylvan! te.

The Lodes Of Cripple Creek.

H. Veins in Basalt, Trachytic Phonolite, etc.

Numerous dikes of nepheline basalt, the last product of the Cripple Creek volcano, occur in the district, especially in its southwestern portion. The Raven, Elkton, Anna Lee, Black

Fig. 12

0 FLuoRtre. / PXRiT Auore.LL0fi06.s

RICH STfEAK5 J IH PHONOLil E.

Diamond, Moose, Bertha, Trail and other mines contain lodes- which are an integral portion of such dikes. They are usually much decomposed, by reason of their basic constitution, and do not make any showing at the surface. Of the several lodes associated with these basalt dikes, the Elkton is the most inter-

The Lodes Op Cripple Creek. 603

esting. A characteristic section is given in Fig. 13, which illustrates this lode as seen in the stopes above the fifth level, in May, 1899. The dike is nearly 4 ft. wide, from A C to B D, and traverses the andesitic breccia of Raven Hill. It shows a distinct lamination parallel to the walls. This is very strong along the outer edges of the basalt, where it is also bleached and decomposed. The central portion of the dike appears as a hard, dark-gray mottled rock, marked by evident cross-jointing. The dike is nearly vertical, inclining slightly to the east The cross-joints dip northward at an angle of about 20°, and facilitate stoping. The basalt exhibits the eflTects of mechanical stress by its lamination, which is suffi- ciently pronounced in places to give the rock the character of shale and to render mining dangerous.

Evidences of chemical alteration are apparent, and they co- incide with the occurrence of ore. The latter usually follows the west wall, but occasionally it is found on both walls, and more rarely in a scattering through the mass of the dike. The total width of ore in these particular stopes averaged about 18 inches.

A remarkable feature of the section is the inclusion, within the dike, of fragments of granite. The largest of these (at Q) is 4 inches wide. In the neighboring stopes such inclusions were frequently seen. This suggests the vicinity of the basal granite. In fact, the level above which this drawing was made leaves the breccia and enters the outer granite at a point only 850 ft. from the place here illustrated. At an intermediate point, where the Elkton dike is not ore-bearing, I secured the section shown in Fig. 15; here larger fragments of granite are in- cluded within the basalt, and the breccia itself is seen to con- tain numerous fragments of the older rock.

In Fig. 13, which is a characteristic section of the lode, the main streak of ore is seen to follow the western boundary of the dike, and to include the rock on either side of that line, so as to obscure it. There is no parting or selvage to mark the line of division between the basalt and the breccia ; that is, it is, as a miner would express it, " a frozen contact" The ore spreads across into both. Both alike exhibit the destruction of their original soluble constituents and the replacement by veinstone, especially fluorite. The breccia is bleached by the

The Lodes Of Cripple Creek.

kaolinization of the feldspar, and is honeycombed with cavi- ties which contain water-quartz in various forms, especially hyalite. The tellurides, sylvanite and calaverite, are scattered through this decomposed breccia and extend into the adjoin-

m

ing basalt. This latter is also bleached to a dull gray, and is seamed with ore along the faces of the cleavages. Although neither the walls of the dike nor the ore-streaks themselves are indicated by selvages, it is noteworthy that several very dis- tinct partings, followed by clay-seams, traverse the basalt in

The Lodes Op Cripple Creek.

60&

lines parallel to its strike. They are shown at G M, H N" K O and L P.

This section presents another interesting feature. It will be noticed that on the east side the breccia is brecciated ; that is the fragmentary rock has been broken again into fragments by a later movement which took place along the course of the dike. It is likely that the other side was similarly aftected, but

Fio. 15

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+: GRNlTt

lA [IT] BASALT

Elkton Dike

I could not determine the fact with certainty, owing to the de- composition of the rock and the deposition of ore. That this movement bears some relation to the period of ore-formation is most likely; that it occurred subsequent to the complete consolidation of the dike is rendered certain by another sec- tion, shown in Fig. 16, obtained in a neighboring level of the same mine. Here a lateral offshoot, A B, of basalt is seen ta

The Lodes Of Cripple Creek.

be clearly broken by vertical movement. The central portion of the dike is dark green, with secondary chlorite, and is speckled by feldspar phenocrysts. The dike, C D-E F, only 11 inches wide at this point, also exhibits a banded structure along the sides, suggesting a differentiation between the core and its

Fkj. 16

Elkton Dike

edges, due to a less complete crystalline development, conse- quent upon rapid cooling at the time of intrusion into the breccia. The latter is seen to contain numerous fragments of granite, for this section, also, was secured at a distance of 500 feet only from the granite rim.

The Lodes Of Cripple Greek.

Another section is illus- trated in Fig. 14, obtained in the same stopes as Fig. 13, but about 50 ft. farther north. The dike, A C-F E, is 3 ft. 10 inches wide. It has a very distinctly laminated structure, and in places it breaks like shale. It is spotted with vesic- ular cavities which are lined with zeolites and hydrous quartz. The ore occurs along each wall of the basalt, spread- ing over into the encasing breccia. No selvage divides the dike from the outer rock, but the bands of decom- posed ore-bearing basalt, A B-C D, and L F-M E, are separated from the central mass of the dike by distinct clay-partings, B D and L M. The ore-bearing edges of the dike are rich in tellurides. That part of the ore-streak which consists of mineralized breccia, F H-E G, appears as a kaolinized rock darkened by spots and streaks of purple fluorite. It is from 2 to 6 inches wide, and is fairly well distinguished from the outer gray breccia by the contrast of color. The enclosing rock is a fairly coarse breccia, marked by sintery spots, due to altera- tion. These are frequently ore-bearing, by reason of tel- lurides. The slips or parallel fractures, S S, also carry a little ore upon their faces, and

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wm

B

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608 The Lodes Of Cripple Greek.

permit the rock to be mined at a profit, because it yields " screenings " or fines, which are rich enough to be sent to the smelter.

In Fig. 17 there is given a characterization of the chief fea- tures of the Elkton lode-structure. The vein is remarkably straight ; in the breccia it appears as one or more small frac- tures carrying tellurides, accompanied by chlorite; when the vein encounters the basalt dike, it follows the latter as long as the basalt maintains a direction similar to the strike of the vein ; when the basalt is crossed by a later dike of phonolite the vein-fractures persist across the phonolite, and spread so as to make a large width of gold-bearing rock.

The trachytic phonolite of Cripple Creek occurs in large intrusive masses, which are penetrated by later dikes of phono- lite and basalt It has a decided porphyritic habit by reason of the occurrence of large orthoclase crystals in a dense ground- mass. The workings of the Legal Tender (or Golden Cycle) property are in this rock, and aftbrd examples of lode-structure. In Pigs. 18 and 19 the Harrison vein is illustrated as it is seen in this mine.

The Harrison vein consists of a band of shattered coun- try in the trachytic phonolite ; the center of it is marked by a leader, usually very rich, bordered by firactured rock having a very variable width. This leader is shown at B E in Fig. 18 and A B in Fig. 19.

In the first example, secured just above the 6th level, B E appeared underground as a streak of crushed rock, 8 to 4 inches wide, and dark-red in color by reason of the oxidation of pyrite* The band of brecciated and bleached rock on the hanging-wall side, from A to B and from E to D, contained numerous little threads and spots of pyrite, accompanied by just sufficient gold tellurides to make it low-grade ore. The corresponding band on the foot-wall, from B to C and from E to F, was less decomposed and exhibited more clearly a defined system of fractures, the latter being lined with fine-grained iron pyrites. In Fig. 19, A B appeared underground as a seam, 1 to IJ inches wide, of white, gritty mud, very rich in gold. The hang- ing-wall, from A to C and from B to D, is brecciated and ore-bearing, as is the corresponding band, A E-B F, on the foot-wall; but the latter, being less fractured, is also less rich than the other side of the lode.

Thb Lodes Of Cripple Creek.

-f- X X -h X t/ X X + X -H X /.

X K -h X -f-/ I

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HARRI.SON VEfN

The widest ore found on the Harrison vein is found at places where spurs or subordinate veins joined the main lode. VOL. xxxni.— 37

J

10

The Lodes Of Cripple Creek.

Fia. 19

fX . 1-

t- X i- X "H X. 1- / +-7-* X , 4- X i- -h X +

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H/iRRlSON VEIN. Hoh

This gives the ore-bodies a disconnected character, a series of linked enlargements, rather than the appearance of a piersistent

The Lodes Of Cripple Greek.

Teak ; when the ore-body narrows, the line of the lode nes indistinct, being indicated merely by a group of irreg- Tactures scarcely different from the fractures to be seen in rosscuts, and not recognized as " veins " simply because do not carry pay-ore.

Fia. 30

.-J-J

. 4

Vein Traversing a Sheet of Pbonolite.

1. Vein Crossing a Sheet of Phonolite.

le occurrence recorded in Fig. 20 represents the Orizaba on Beacon Hill, as seen in September, 1899. The coun- j granite, which, in this part of the district, is penetrated iveral sheets and intrusive cores of phonolite. The Orizaba cuts through at least two of these flat intrusions, and in 5 so presents several interesting features. Fig. 21 illus- s the relation between the geological structure and the

The Lodes Of Cripple Greek.

mine-workings at 220 ft. below the surface. The phonolite is from 9 to 11 ft. thick, dipping flatly both northward and west- ward. At the south winze the phonolite is cut at a point 4J ft. down, and is found to extend thence to a depth of 18J ft. The remainder of the winze, to the bottom, at 28f ft., is in granite. The north winze, which is 77 ft. distant from the other, penetrates phonolite at 13 ft., and strikes granite again at the bottom, 23 ft. down. The phonolite is faulted about 14 in., B to C and D to E, Fig. 20, by the fracture which marks the line, A B D F, of the vein. In the granite the vein ap- pears as a narrow seam, but in its passage through the phono- lite it opens out and forms a series of cavities which are lined with long prismatic crystals of sylvanite, encrusted with quartz, affording specimens of great beauty, and, of course, of extra- ordinary richness. The tellurides also impregnate the rock encasing the fracture,

rig. 21

This shows the Belation of the Phonolite Sheet (Fig. 20) to the Workings.

In crossing the phonolite, the lode-fracture straightens up ; in leaving it, and passing into the granite again, it flattens. While traversing the 9- to 10-ft. sheet of phonolite, and for a farther distance of 15 to 20 ft. into the granite above the phonolite, the vein carries very rich ore, forming a flat body, the pitch of which conforms to the dip of the phonolite. Farther up, the vein becomes impoverished, until, at a point 85 ft. above the 220-ft. level, it encounters another flat sheet of phonolite, characterized by a repetition of the conditions just described. In the stopes above the 220-ft. level the granite is mined not only for the 4 or 5 inches of vein proper, but also for as much as 5 or 6 ft. into the hanging-wall, which is tra- versed by telluride threads, parallel to the line of the vein. In the phonolite the vein is characterized by " vughs " or cavities, 2 to 8 inches wide, yielding an average of about 5 inches of rich ore. This rich ore does not continue downward into the

Thb Lodes Of Cripplb Greek. 618

grauite under the phonolite ; the vein thins out, becoming a mere thread amid a series of parallel seams, which give the granite a schistose character for a width of one foot.

J. General Observations.

The occurrence of ore in the Cripple Creek district is inti- mately related to the distribution of fractures. As a rule, the veins, in their strike and dip, exhibit an evident sympathy with the dikes, more particularly those of phonolite, which are also the most numerous. It is true that the locality of Bull Hill is crowded with a very large number of veins which appear to be independent of dikes, but it is a fact, proved by the experience of mining in the district, that these numerous veins are less persistent and carry ore-bodies which are more uncertain than those, for example, of Battle Mt. and Raven Hill, where the veins are obviously connected with dikes. It is possible to go further and state that the explorations carried out in the ex- treme eastern and western parts of the region, such as the eastern part of Gold Hill and the corresponding slope of Big Bull, both of which are still well within the volcanic area, have tended to prove that the absence of dikes means the want of a factor usually very favorable to the finding of ore. Nor is this a matter of surprise. The veins are obviously the sequel to the volcanic activity which occurred in this region, and it is a reasonable deduction that the agency of ore-precipitation was linked to that of the thermal waters which marked the last stage of the dying volcano.

The principal veins, such as those which have made rich mines out of the territory controlled by the Independence, Portland, Strong, Gold Coin, Granite, Anaconda, Elkton, Gold King and other companies, either follow dikes or have a course lying closely parallel to them. It is noticeable that the later fracture constituting the vein is apt to be straighter than the older line of fracture occupied by the dike ; so that the vein may be compared to a road, alongside a river, which avoids the excessive bends of the latter and keeps a course as straight as is consistent with a given general direction, namely, that of the river. The Independence main lode illustrates this observa- tion, as the accompanying plan will indicate. (See Fig. 22.) This exhibits a portion of the first level where the vein is mostly in the granite. It will be seen that when the vein-

The Lodes Of Cripple Creek*

fracture encounters the phonolite dike it follows the latter; or looking at the occurrence from the opposite standpoint, when the phonolite makes a sharp turn to the west, the vein main* tains its general strike. Near No. 1 shaft the vein crosses the

o

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O

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O

dike. This is shown in greater detail in Fig. 23, at E D, where it is evident that the vein-fracture persists in its course despite the fact that it has to cross the sharp bend made by the dike. Afr the place of crossing, E D, there are one or two small stringers of ore which serve to connect the lode on either side of the pho-

The Lodes Of Cripple Creek.

e. Between C and E the ore, here 4 ft. wide, narrows 1I5 by steplike euocession, from one joint-plane in the grant D the next. Beyond the No. 1 shaft, as will be seen in

22, the lode widens until, at the contact, it is 10 to 15 ft. ss. At this contact, where the overlying breccia rests on j[ranite, the ore is in decomposed granite, having no marked idaries save where, on the east, it lies against the dike. lediately north of the contact the vein narrows and crosses ;>honolite only to disappear. At lower levels it has been id much farther northward.

iie obvious connection between phonolite dikes and veins led to the idea that phonolite itself is notably an ore-

JNtjePETNOENCE. GROSSIMO OfKE

ier. This is scarcely true. The details of lode-structure ribed earlier in this account indicate that the gold-ore ob- ?d from the phonolite comes mainly from the places where jre-bodiea in the granite or in the breccia are in immediate act with the dikes ; or, if ore is found within the phonolite

f, it is at. isolated spots, where the line of a lode crosses a and makes a scattering along the fractures produced by

crossing. Mistakes in this connection have been made by omiding phonolite with certain finer-grained breccias and

which, by impregnation with quartz, have put on the ap- ance of a close-textured crystalline rock. This happens uenth in the mines on Gold Hill. Where valuable ore is ly taken from phonolite, it will be found that its true char- r is sufficiently indicated by the fact that it is secured in

form of " screenings." The fine, powdery material ob- ed by passing the ore over a wire-screen (which separates

616 The Lodes Of Cripple Creek.

all the larger fragments, and concentrates the small proportion of rich ore), occurs as an encrustation, of fluorite and tel- lurides, which lines the numerous cracks of a phonolite dike. That shattering of the dense, fine-grained siliceous rock ap- pears to be an essential factor in the deposition of the ore. In this connection it is a notable fact that the phonolite dikes are found occasionally to widen into tongues or cores of large dimensions, which, if they lie on the strike of a series of veins, are so much shattered as to permit of a generous dis- semination of ore. Such an ore-body, of noteworthy size and richness, occurs in the Independence mine at the second, third and fourth levels, pitching northward more flatly than the con- tact with which it was originally supposed to coincide, causing a confusion of ideas very detrimental to the development of the mine.

The chief characteristic of the ore-bodies of Cripple Creek is that they are essentially impregnations spreading outward from lines of fracture ; therefore, it is not surprising that the distribution of ore is aftected by the changes in country. Prof. Penrose has pointed out that " the character of the fissures of the district is much affected by the nature of the rocks they intersect,"* and it is but a further step to connect this observa- tion with the distribution of ore. In discussing this aspect of the inquiry it is preferable to avoid the use of terms such as " fissure," with its old associations of open crevasses and gaping cavities, and to risk the weariness of iteration by employing the word " fracture," which goes no further than to suggest dislocation or breaking without necessarily bringing in the idea of an open space, because the experience of mining in the Cripple Creek district is all against the theory that open spaces are the necessary adjuncts to ore-deposition ; and Mr. Becker's well-known dictum, made in connection with the Comstock lode, that "the first condition for a deposit of ore is the formation of an opening,"! is daily contradicted by the under- ground workings of this district, as it has been by many others with which I am familiar. The open spaces which are fre- quently encountered, especially in the mines situated on the

Geology and Mining Industries of the Cripple Creek District," p. 143. t U. S. OeoL Survey, Monograph iii., p. 287.

The Lodes Of Cripple Creek. 617

south slope of Bull Hill and on Ironclad Hill, are, as a rule,* notably unfavorable to the finding of ore ; and while certain veins, among which the Bobtail, in the Independence mine, may be instanced, are indeed marked by frequent " vughs " or cavities, these cavities do not contain ore, nor is their presence a factor in connection with the distribution of good ore ; quite otherwise, all such "pot-holes" are disliked by the mine- foremen, because they coincide with lean places ; and by this is understood not only poverty in respect of gold-bearing min- erals, but also an absence of gangue, such as quartz, fluorite, and the other constituents of the ores of the region. This all oes to show that the term "fissure" and the associations which go with it are to be avoided in an attempt to convey the real nature of the lode-structure, because it cannot be empha- sized too much that the ores of the district occur as a dispersion into the rock where it is traversed by lines of fracture, not only in the fracture itself, which is often only a mere parting, but also along the minor cracks and porosities of the enclosing rock.

The physical and chemical characters of the rock — the first more than the second — are, consequently, a primary factor in determining the shape and extent of the impregnation which <Jonstitutes the lode. Close-grained rocks are apt to be more fissile and less porous ; coarse-textured rocks are likely to break in a larger, more irregular manner, but they are often more penetrable by solutions. The phonolite and the breccia exhibit extreme divergence in this respect. Granite resembles the breccia because it is coarsely granular, but its jointings are more regular ; basalt resembles the phonolite in texture, but, on account of its basic composition, the weak places in it are more readily searched out by corroding waters.

This " structural dependency " (as it may be termed) of the lodes in relation to the rock is manifested not only by the char- acter of the vein-fractures, but also in the manner of their im- pregnation by ore. Thus, while the bands of ore in granite are often wanting in walls, yet on the whole they are less lack-

An interesting exception was recently encountered on the seventh level of the Elkton mine, where a cavity, having maximum dimensions of 20 x 20 x 35 ft, was found to contain ore and water. The latter was struck in such quantities as seriously to impede operations ; the ore occurred in a mass of brecciated rock, lining the fractures and penetrating the shattered country, especially near the periphery of the mass. It looked like a thermal spring which had become choked before reaching the surface.

618 The Lodes Of Cripple Creek

ing in definition than the breccia, because structural lines in the granite, such as jointplanes, have served as barriers to in* definite impregnation. On the other hand, the breccia, not being composed of a crystalline granular material, but being built up by fragments which are confusedly mingled together, has no defined system of joints, and the width of the impreg- nation which constitutes the ore will be determined by purely local conditions of fracture ; the lodes may have no walls, and, when they are limited by such boundaries, these are apt to be cracks sympathetic with the main vein-fractures and parallel to them. In the phonolite the limits are set up by the sheeting of that rock ; the ore, which is infrequently found in phonolite, occurs then as a lining or powdery encrustation upon the faces of the laminae, and not, as a rule, within the 'matrix of the rock itself. As the lamination is parallel to the walls of these dikes, the width of ore also has a shape conforming to them.

Faulting on a large scale is conspicuously absent in the mine- workings ; that is to say, there is no evidence of extensive movement since the ore was deposited. Penrose has recorded his opinion that " the fissures represent fault-planes of slight displacement."* The amount of this displacement is not meas- urable, because, as a matter of fact, the multiplicity of the fracturing and the subsequent precipitation of ore has obscured it most effectually, and it is this character of multiple fracture which pervades the entire structure of the volcanic area. To what extent these fractures are merely shrinkage-cracks and to what extent they represent radical movements due to the readjustment around a volcanic orifice, I cannot say. In so far as the question concerns ore-deposition, one can emphasize the fact that all breaks, from a crack to a crevasse, are the outward and visible signs of displacement; for without displacement the fracture is only latent, and a latent fracture has no possi- bilities for ore-deposition and does not concern the mining ge- ologist. Since the ore was formed conditions of comparative rest must have supervened, for this is a direct inference from the comparative absence of faults. This fact, taken with the known age of the volcano, which broke out so late in geological time as the end of the Eocene or early in the Miocene period, points to the recency of the agencies which made the ore-deposits.

"Geology and Mining Industries of the Cripple Creek District," U. S. Geol* Survey y p. 153.

Biographical Notice Of Clarence King. 619

Biographical Notice of Clarence King.

By R. W, Raymond, New York City.*

(New Haven Meeting, October, 1902.)

Clarence King was born January 6, 1842, at Newport, R. His ancestors on both sides were New Englanders, of English blood, and among them not a few distinguished themselves in art, science, politics or commerce. His grandfather, Samuel Vernon King (partner in 1803 in the house of Talbot, Oly- phant & King, later known as King & Co.), was a pioneer in the China trade, and four of his sons succeeded him in the business. Three of the four died in the far East ; and one of

In the preparation of this paper I have heen assisted by Messrs. James T. Gardiner and James D. Hague, of New York City) and S. F. Emmons, of Wash- ington, D. C, each of whom is better equipped by personal knowledge than I am, to give a comprehensive account of Clarence King's life, work, and charac- ter. It was, indeed, my desire that one of these intimate friends of his should write this notice, and that I might be permitted to add my personal tribute, with such recollections and impressions of my own as it might comprise. This plan proving to be impracticable, I suggested, and they accepted, the sdieme of a joint authorship. But the work grew under my hands until it came to comprise much for which I alone was fairly responsible, and, in justice to them, I can now only assume that responsibility, thanking them for the cordiality with which they have freely placed at my disposal much material, both unpublished and published. Under the latter head I may mention the articles by Mr. Emmons in the Eng, and Min, Jaur.y Dec. 28, 1901, and Am, Jour, of Sciy March, 1902 ; and those of Mr. Hague in the Overland Monthly Nov. , 1873, and the N. Y. Evening Posty Dec. 28, 1901.

I would express also my thanks to Prof. Wm. H. Brewer, of the Sheffield Scientific School of Yale University, for many facts and reminiscences concerning King's earlier career, of which I have made good use, both by direct quotation and otherwise.

This paper was read by title at the Philadelphia meeting of the Institute, May, 1902 ; but it was not completed until just before the New Haven meeting, in Oc- tober, at which it was read in full. In view of this fact, and the other fact that Clarence King was a graduate of the scientific school connected with Yale Col- lege (now known as the Sheffield Scientific School of Yale University), it has been deemed proper to withdraw the title of the paper from the Proceedings of the Philadelphia meeting, and make it in name, as in fact, a part of the proceedings of the New Haven meeting. — R. W. R.

620 Biographical Notice Of Clarence Kino.

these was James, the father of Clarence, who was obliged, in order to take the place of his elder brother, to leave his young wife before the birth of his son. He died in 1848, leaving his property invested in the business ; and in 1857 the house of Xing & Co. was ruined by the loss of one of its steamers, car- rying a large amount of specie. The young mother, widowed in her twenty-third year, devoted herself to the education of her only son, pursuing for herself many studies, that she might teach him ; and becoming at the outset, as she remained always, his sympathetic and competent intellectual companion. On his part, he began as a " mother's boy " — best of all beginnings ! — and as a mother's boy, maintaining still in undiminished fervor and unstained purity the filial reverence and affection of child- hood, he ended — best of all endings !

His early years were spent at Newport. At about thirteen he entered the High School at Hartford, Conn. He had already shown the characteristic qualities of physical strength and ac- tivity; love of nature and the natural sciences (exercised in hunting, fishing and botanizing during summer vacations in the Oreen Mountains) ; an almost equal passion and appreciation for literature and art ; . great powers of entertaining conversa- tion ; singularly quick observation and wonderful memory, and (as the poet Stedman lately said of him) " the gift of friend- ship " — a gift which Mr. Gardiner, his schoolmate at Hartford, declares to have been as marked in him at fifteen as at fifty. I cannot do better in this connection than quote his friend's sum- mary description of King at that period :

*'0n Saturday, we usuaUv spent the whole day walking in the country. If any question arose as to any object seen during the day, whether we had particularly noticed it or not, King could always describe it from memory with great minute- ness. He seemed to photograph unconsciously everything that passed before his eyes, and to be able to recall the picture at will. He studied enthusiastically the botany, the bird and animal life, and the rocks, of the regions over which we rambled.

" Already at fifteen he wrote beautifully, having been trained in literary judg- ment and skill by his mother, who possessed in high degree both the faculty of expression and power to inspire enthusiasm. From her he received also, besides his literary and artistic tastes and critical perceptions, an ardent hatred of slavery, and a clear foresight of the impending irrepressible conflict' of the Civil War."

In 1859, at the age of seventeen, King entered the Sheffield Scientific School at New Haven. At that time the material

Biographical Notice Of Clarence Kino. 621

facilities and endowments of this institution (or, for that matter,, of any other American technical school) were such as we should now regard as ludicrously inadequate to the demands of modern scientific and industrial training. But the Shefiield school had great teachers, who were able to inspire, as well as instruct,, many strong leaders of the next decade. Munificent endow- ments can accomplish much, no doubt. They can create (as they have created, many times within the last half-century), in magical growth like that of Aladdin's palace, splendid build- ings and apparatus, rivalling if not excelling the slowly accu- mulated educational " plants " of the Old World ; but money cannot evoke at a word such men as James D. Dana and others like him — pioneers, prophets, leaders, organizers and creators, as well as patient toilers — always learning, while always teach- ing, and winning fame because they did not think about it, but simply deserved it At the time when King entered the Shef- field school I was pursuing my own studies in a similar direc- tion abroad ; and I remember well the thrill of patriotic pride with which I heard my instructor in mineralogy — himself a man of world-wide reputation — declare that in that department the best book ever published was the wonderful Mineralogy of Dana.

But I must not wander too far — yet this is scarcely wander- ing ; for it was Dana, and his worthy assistant (and afterwards successor), George J. Brush, under whom King, with such classmates as 0. C. Marsh, Arnold Hague and Samuel Parsons,, as well as many others before and after them, received the impulse and training which have borne fruitful results in American history. For such men as these, not less truly than the soldiers of the Republic, discharging the duty devolved upon them by the most critical and glorious half-centnry of re- corded time, effected the preservation of a nation, the industrial conquest of a continent, and the scientific as well as the com- mercial leadership of America.

During his college course. King was not only active in scien- tific field-work, but also (as might have been expected) a leader in athletic sports — captain of a base-ball team and stroke-oar of a racing-crew. In 1862 he was graduated as B.S., — a de- gree which his class was the first to receive from Yale college then just waking to the worthy academic rank, as well as ma- terial value, of a scientific course.

622 Biographical Notice Of Clarence King.

During the following winter he studied glaciology under Agassiz, and was an active member of an art-club, which studied with enthusiasm the eloquent dissertations of Ruskin, and the work of the American pre-Raphaelitic school.

In May, 1863, together with his friend Gardiner, whose health had been somewhat impaired by over-study, he started for California, intending to make the journey on horseback from St. Joseph, Mo., then the most western railway-terminus. On this journey his faculty of universal sympathy and conse- quent power of winning friends was strikingly illustrated. On the cars, his kindly attention to the children of a family of emigrants led to the adoption of himself and Gardiner as mem- bers of the party in its trip across the plains. The two young men, mounted upon their own horses, were able, by reason of the slow progress of the wagons, to make numerous detours upon excursions of exploration, though not without danger from hostile Indians. The party followed the " old Fremont route," up the North Platte, and down the Humboldt in Ne- vada, thus traversing the transcontinental belt which King was afterwards to survey ; and in this way he gained, no doubt, that general impression of its varied geological features and mineral resources which led him to select it as a fruitful field of study. After crossing the Nevada deserts, the two friends left the party, to visit the already famous Comstock lode. The very night of their arrival at Virginia City the house in which they lodged took fire, and all their personal property was de- stroyed. They took the situation with light-hearted courage, and worked as laborers in one of the quartz-mills until they had saved enough money for further traveling-expenses. Then they made their way on foot across the Sierra Nevada and down to Sacramento, where they took steamer for San Francisco.

This adventurous journey, taken in connection wath King's subsequent career, reminds me irresistibly of a feature in the life of General William T. Sherman — a man possessed of the same tireless activity, hunger for new knowledge and faculty of perceiving, comprehending, retaining and, at need, effec- tively utilizing, any facts he had encountered, however casually. When asked, in his old age, how he had dared to cut loose

Biographical Notice Of Clarence King. 623

from his base of supplies and risk his whole army in the bold march from Atlanta to the sea, Sherman replied that he would not have dared it, in the absence of detailed maps and other in- formation, but for the circumstance that many years before, as a young Lieutenant of the Engineer Corps, serving in the South, he had studied every stream, hill and road in that re- gion, and learned, never to forget, the difficulties and resources of the country; so that in undertaking what seemed to others a blind and hazardous venture, he " knew what he was about." We shall see that King's great scientific exploration from the Missouri to the Sierra was rendered practicable, at the particular period of its execution, by reason of the early reconnaissance which he had made in person.

On their way to the Golden Gate, the two friends accident- ally made the acquaintance of Prof William H. Brewer (an -assistant in the Geological Survey of California); and both were drawn into the service of that survey, then recently organized under Prof J. D. Whitney.

From a private letter of Prof. Brewer's, I make the following interesting quotation :

'I first met Clarence King and his intimate friend, James T. Gardiner, on Aug. 30, 1863. I had been making, that summer, a reconnaissance in the Sierra Nevada, beginning in the extreme southern part, at Tejon, and zigzagging six or €ight times across the divide, my last crossing having been from the northern end of Lake Tahoe to Forest Hill. My party had been reduced by sickness and other causes until, during the last four crossings, I had with me my packer only. It was my desire to continue the reconnaissance northward as far as Lassen peak ; but another man, at least, was needed — especially as the Indians were reported to have broken out from Lassen peak to the Shasta valley. So I had left my ani- mals with my packer at Forest Hill and started for San Francisco to see my chief, Prof. J. D. Whitney, with regard to the necessary assistance, and to inter- view the Indian agent and the military authorities concerning the reported Indian war.

On the Sacramento river steamer I noticed two young men conversing to- gether in low tones, and curiously glancing from time to time at me, attracted, no doubt, by my costume and appearance, which indicated that I was engaged in rough mountain- or forest-work of some kind, yet not that of the hunter or the miner. Presently they drew near, and the younger one (King) asked, Is your name Brewer?* Yes,' I replied. Belong to the California Geological Sur- vey?* Yes.' Well ; I had a letter of introduction to you from Prof. Brush ; bat it was burned up the other day !' He went on to say that he had been for three years at the Yale Scientific School (as it was called when he entered it) ; and that he and his friend had crossed the plains, the interior basin, and the Sierra, since leaving New Haven. Of course, we began at once an acquaintance which soon liecame, and always remained, a cordial friendship. Many years after, he wrote

624 Biographical Notice Of Clarence King.

on the fly-leaf of the second edition of his Mountaineering in the Sierra Nevada (the most brilliant and fascinating of books on mountain-climbing), these words, which I treasure with affectionate pride : To Professor W. H. Brewer, my earli* est and kindest Sierra friend, to whose friendly guidance I owe my first and my most charming mountaineering, with the unchanging regard of the Author.'

I may be permitted to introduce here a reminiscence which is likewise most gratifying to me, as showing the part which I unconsciously took in bringing Clarence King to California, and thus initiating the career which was to makis him illustrious.

'' Both during our earliest conferences and on several later occasions. King told me that Mount Shasta was the magnet that had drawn him irresistibly to the Pacific coast. This magnificent mountain then possessed a pre-eminence io popular estimation which it no longer possesses. It was believed to be the high- est peak in North America. Its altitude had been variously reported at from 14,000 to 18,000 ft From the first, the members of the California Survey looked forward with eager anticipation to a thorough examination of it. We had two barometers made with scales which would show an altitude of 18,000 ft, and after collecting all available information, I was expecting to ascend Shasta in September, 1862. It was a very malarial year, and nearly all my party came down with fever. Of those who were able to work, some had to be distributed to observe station-barometers, for the subsequent comparison with the summit-read- ings. The rest, accompanied by Prof. Whitney, who came from San Francisco for the same purpose, proceeded to the western base of Shasta, and made the ascent to the summit Sept. 2, 1862. It was the first time that the altitude of a mountain in the United States, more than 14,000 ft. high, had been accurately measured ; and we were naturally proud of the achievement A few days later I wrote to a very old friend and classmate. Professor George J. Brush, an enthu- siastic account of our adventure, emphasizing not only the scientific interest, but also the sublime and majestic scenery connected with it. To Clarence King, who happened to call upon him soon after the receipt, Prof. Brush read this letter ; and, as King told me many times, that settled it' He resolved to see California, and, in particular, Mount Shasta.

''To return to my narrative: I liked King from the first ; he gave me much comparatively recent information concerning my old friends at Yale ; I told him my plans ; and we arranged to meet in San Francisco. And, at my invitation, he called several times at the office of the Survey in that city, deepening on each occasion my growing affection and esteem for him. I was intensely anxious to get into the Lassen peak region. The year before, I had passed it, going up and down the great valley west of it, and had traced the Cretaceous formation, finding it, at one point, overlain with lava. I now wished to get into some of the cafions which cut through both the lava and auriferous series. All this could be done with safety ; butthe Indian agent said it would be madness to try to go through, north of Lassen peak, to Shasta valley. I decided to start anyhow, and go as far as I could. King wanted to go with me, as a volunteer without pay. The possible danger of the trip was an additional temptation to him. And Prof. Whitney (who was likewise captivated by his light and ardent nature) authorized me to engage him.

''Clarence King was then in his 22d year, but looked much younger. Of course, he was not so thoroughly informed or so deeply interested in geological problems as he afterwards became. In fact, he stood on the threshold of that fascinating study, saturated chiefly with Auskin and Tyndall. The remarks of the latter on the glaciers of the Alps were constantly upon his lips.

Biographical Noticm Of Clarence King* 625

The trip was notable in many respects, and suggested many topics of inquiry which afterwards bore fruit in King's receptive, retentive and intensely active mind. Lassen peak was reported to have been, only a few years before, an active volcano, and offered an opportunity for the study of recent eruptive rocks. The possible glaciers upon Shasta were discussed, as was also the age of the gold-bear- ing rock-zone of the Sierra, and the desirability of a geological section across the range. Incidentally, the larger sclieme of a transcontinental section was men- tioned. This had been the dream of Whitney in 1862, when the construction of the Pacific railways was actively begun. He thought that when once a section across California had been completed the railroad companies might be inclined to pay for making one along their lines, across the interior basin and the Rocky mountains, to the great plains.

'' We ascended Lassen peak twice, on the 26th and 29th of September, 1863. The first time the day was unpropitious for good barometric work. There was a fierce wind on the summit ; a storm was approaching, and the barometer was fall- ing rapidly ; and the whole Pitt river valley was fiUed with clouds, hiding every- thing below the altitude of 8000 or 9000 ft. But all was clear above, and Shasta, 80 miles away, with the tops of the adjacent mountains only, rose from the white mountain of cloud, projected against an intensely blue sky. King's exclamation was, ' What would Buskin have said, if he had seen this P

On the way back he wanted to try a glissade down one of the snow-slopes. I objected strongly, being uncertain whether it would be practicable for him to stop before reaching the rocks at the bottom. But he had read Tyndall ; and what was a mountain climb without a glissade f So he had his way, and came out of the ad- venture with only a few unimportant bruises.

Three days later, after the end of an uncomfortable storm of rain, snow and sleet, we made a second ascent of the peak, going up in the night, by bright moon- light, and arriving before sunrise at the summit, where we spent ten hours. The sky was cloudless, and the atmosphere transparent in the highest degree. For a short time after sunrise we could see Mt. Hamilton in the south — normally below the horizon, but ' looming up ' long enough and plainly enough for satisfactory identification. This is the longest distance at which, so far as I know, I have ever seen a terrestrial object. Another spectacle of unique perfection and grandeur observed on that occasion was the shadow of the peak projected on the west- em sky. Although I have often reached greater altitudes, that day stands out in my memory as one of the most impressive of my life.

''It will easily be imagined with what satisfaction and delight these experiences were shared with such a companion as Clarence King, to whose glowing enthusi- asm they were new as well as grand. Again, he was fascinated by Shasta. Three days before, the snow upon it had been in patches and streaks ; now the snow had covered with unbroken white — save here and there a protruding rock — the upper 4000 or 5000 feet of the mountain. The lower limit of this cap was a sharply- defined 'snow-line.' The great white cone standing upon the dark base, against a background of intense blue, was a memorable picture, and deserved King*s rhapsodies of admiration.

"It was in the earlier part of this expedition that the first discovery of the Jurassic and Triassic fossils in place in the auriferous zone of California was made in the Genesee valley, Plumas coimty. (See Am, Jour. ScL 2d ser., vol. xli, p. 353; also, Oed. Survey of Oal., "Geology," vol. i., pp. 308, 482.)

" The next year, King and I passed around the eastern base of Shasta. The reconnaissance of this mountain had been made by the California Survey in 1862, VOL. zxxni. — 38

626 Biographical Notice Of Clarbncb King.

after a winter noted for the heaviest rains and snows since the acquisition of Cali- fornia. And we had then announced that, while there was much snow on the mountain, there were no glaciers. King had never seen glaciers; I had seen them only in Switzerland.

'We forded one day at the base of Shasta a small stream, turbid with ash- colored mud, which came from a snow-field far above. I said that, if we were in Switzerland, I should consider it a typical, glacier-fed stream. Why is it not?" insisted King. I told him I had been, only a year before, on the upper part of that very snow-field, and that it showed neither ice nor crevasses, I thought the turbidity of the water was due to volcanic dust.

Six years later, in 1870, King discovered actual glaciers on Shasta, and in 1871 described them in the Atlantic Monthly imd in the American Journal Science. Two years later, or ten years after our fording the turbid stream, he said to me, 'That stream haunted me for years, until I got on Mt. Shasta and found the glaciers !'

''That was an illustration of the way in which his retentive as well as percep- tive mind stored up, and ultimately used, the facts and suggestions it had once received. Another occurs to me. On our trip, in 1863, 1 talked much about the value of large photographs in geological surveys. I had taken a fancy to stere- optical views especially ; and I thought the broken country about Lassen peak should be photographed, and could not be shown satisfactorily by drawings. In later years King was the first to carry out these ideas on a grand scale ; and now the camera is an indispensable part of the apparatus of field-work in such surveys. Many similar instances might be given in which King did the things of which others had dreamed.''

The foregoing reminiscenceB of his friend and, at that time, his immediate chief, abundantly indicate the qualities of ambi- tion, energy and endurance which soon won for the young athlete of Yale recognized leadership in the field. The story of his ascent of Mt. Whitney (14,898 ft. above tide), the highest peak in the United States, outside of Alaska, affords an inter- esting and, in some respects, amusing illustration.

The whole somewhat complicated story is told in an article by Mr. Hague in the Overland Monthly for Nov., 1873, from which it appears :

That the name of Mt Whitney was given in 1864 to the highest of a noble cluster of peaks at the head-waters of the Kern and King rivers by a party of the California Geological Survey, under the direction of Prof. Brewer, and including Clarence King, which was at work in that region during the summer of that year, and some of whom (including King, of course — when was he ever left out, if an adventure was on the programme ?) ascended a peak which they called Mt. Tyndall, and from which they saw two others, still higher, to the loftier of which they gave the name of Whitney, their distinguished

Biographical Notice Of Clarence King. 627

cliief ; that later in the same year, after the party had been withdrawn, King made an unsuccessftil attempt to reach this topmost summit; that in 1871 (when no longer connected with the California Survey) he returned, with characteristic perti- nacity, to this endeavor, and climbed to what he supposed to be the top of Mt. Whitney, but was prevented from identifying his position by " dense, impenetrable clouds;"* that in July, 1873, Mr. W. A. Goodyear, formerly of the California Survey, with a companion, ascended the summit last named, and clearly saw another and higher one, which was the true Mt. Whitney, already located by observations from other mountain stations, and located upon official maps. This truly highest summit has since been reached by many parties.

Whoever cares to unravel the intricacies of this narrative %vill find in Mr. Hague's article, already cited, an efficient guide. To me, I must confess the only important and interesting item in the series is the circumstance that in 1873, as soon as he had heard of the observations of Mr. Goodyear, Clarence King, though no longer connected with any public work re- quiring from him further attention to the matter, left New York, and, at his own expense, traveled without a moment's delay to the locality concerned, and ascended the true Mt. Whitney, simply to settle, for his own satisfaction, the question which (to use the felicitous phrase quoted above by Prof. Brewer) would otherwise have " haunted him."

Another incident of his work in California deserves mention — namely, his discovery in January, 1864, on the Mariposa es- tate, of fossils determining the Jurassic age of the gold-bearing slates of California. There was at the time a controversy over the question of "priority" in this settlement of a scientific question. Prof. W. P. Blake had undoubtedly found paleon- tological evidence tending to the same conclusion. After a laborious study of the contemporaneous documents, I am led to believe that the discovery in placCy in 1863, of Jurassic and Triassic fossils in the Genesee valley, in Plumas county (men- tioned on p. 625), was the earliest well-authenticated and decisive one, and that the credit of this discovery belongs to Prof. Brewer, though it was, in Whitney's subsequent official re- ports, attributed to him and his assistant King jointly. But

♦ This aBcent is described in King's book, MomUaineering in the Sierra Nevada.

628 Biogbaphical Notice Of Clarence King.

it was not regarded as decisive by Whitney, because it did not include the observation of actual gold-bearing veins in the same rock. The Mariposa discoveries made by Blake and King in the country-rock of known gold-mines were conclu- sive. The question of priority as to these discoveries, involv- ing, as it does, the date not only of the discovery, but also of the first public announcement and the first publication thereof, is really trivial ; at least, it will not be discussed here. The record of science is not that of a patent law-suit, in which mere priority governs important rights of property; and neither Blake nor King needed to rest his claims to scientific recognition upon a controversy so unimportant.

His connection with the California survey lasted until the end of 1866 ; but during that period he was twice loaned, so to speak, for other service — once to the Mariposa Mining Company and once to the United States. The latter episode occurred in the winter of 1865-66, when he acted as scientific assistant of Gen- eral McDowell in a reconnaissance of the desert regions of Southern California and part of Arizona. His friend Gardiner was detailed to the same expedition. That it was not free from danger, no one acquainted with the condition of Arizona and the temper of the Apache tribes at that time need be told, and others may learn from the following anecdote, which I heard from Mr. King himself, and which Mr. Gardiner con- firms:

One day, on the road to Prescott, Ariz., the two friends, ab- sorbed in their work, had ridden ahead, beyond sight of their cavalry escort, when suddenly a couple of Apaches sprang from the bushes, under the very noses of their horses, with arrows aimed at their breasts, drawn to the head, and each held from fatal flight by a single hand. Gardiner's first im- pulse was to draw his revolver; but King restrained him, divining instantly that the two visible assailants were not alone, and that resistance would be useless. Sure enough, at a signal given, some fifty Apaches emerged from the chapparal and surrounded them. They were ordered by signs to dismount and disrobe. Intent on saving precious time, during which the cavalry might come to their rescue. King distracted the atten-

Bioqraphical Notice Of Clarence King. 629

tion of the savages for several minutes by exhibiting to them his cistern-barometer, and explaining, in Spanish and by signs, that it was a new-fangled gun of very long range. The delay thus gained, however, did not prevent their captors from pre- paring thongs for their captives, and lighting a fire to be placed upon their breasts, Apache fashion, after they should have been laid, naked and bound, upon the earth. Indeed, they were already half-stripped when the cavalry became visible, and, perceiving the situation at a glance, charged the Indians with such vigor and speed as to capture two of them and scatter the rest. (The two thus taken were released, because the troops were not strong enough to fight the whole Wallapai tribe, as they would have had to do if they had attempted to hold their prisoners.) There is no doubt that King's presence of mind, coolness and ingenuity saved the lives of his friend and him- self.

However keenly he enjoyed such explorations of new re- gions, he realized, as an employee of the California Survey, the importance, as a matter of policy, if no more, of preserving the popular approval and securing the most immediately useful fruits of that great work, by giving greater special attention and prompter publication to the economic features of it. In 1866 he secured the promise of this change, and also (through his personal acquaintance and persuasive personality) assisted largely, if not decisively, in obtaining the necessary legislative support. At one time, I think, he expected to be put in charge of this department, or, at least, of some important division thereof. But circumstances led him to resign from the Cali- fornia survey, and to attempt a larger undertaking on his own account.

Concerning the reflections and considerations which pre- ceded this step, Mr. Gardiner contributes the following inter- esting reminiscence :

'' In the summer of 1866 King and I were working together on a suryej of the region east of the Yosemite VaUej. I had previously developed and tested methods of topographical work, based on triangulation from peak to peak without signals, and gradually expanding the scale of the triangles, until I believed that the system could be applied to very large areas in a country where peaks were sharp, so that the closure of the triangles could be made very accurate, compared

630 Biographical Notice Of Clarbnce King.

/ with what had been done in reconnaissance-work. During that summer we dis- cussed the possibility of carrying across the whole Rocky Mountain system a sur- vey based on rapid triangulation without signals, checked with astronomical work, and with topographical work following the methods which were used in the Yosemite Valley survey and field-work of 1866.* We believed that by the applica- tion of these improved methods in topography a geological survey was possible which would be far in advance of anything done in the geological survey of Cali- fornia, or any other geological work previously done in the western mountain- system.

''Sitting on the high peaks of the Sierra, overlooking the deserts and ranges of Nevada to the eastward, we worked out the general outlines of the 40th-paral- lel survey-work. It was the natural outgrowth of our jouruey across the plains our experience on the California survey, and our exploration of Arizona, coupled with King's great aggressive energy and consciousness of power to persuade men to do the thing that he thought ought to be done.

''Our study of the structure of the continent in our journey of 1863 across the plains, and in our Arizona trip of 1865, led us to feel that the survey of Oili- fomia and the problems to be solved there were but a part, and possibly a minor part, of the great problems of the structure, topographical and geological, of the whole mountain-system of western America from the plains to the Pacific, and it was from this point of view that the great continental cross-section on the 40th parallel was planned. If King had taken charge of the department of economic geology in the California survey, the execution of this wider plan might have been delayed ; but the plan itself was conceived without reference to our tempo- rary California work."

The new scheme was nothing less than a transcontinental topographical and geological survey, for which, with sublime audacity, King undertook to obtain, from the Executive and from Congress, the authority and the means.

Yet the idea was not so chimerical as might have been supposed, and King's intuition of its practicability was truer than any judgment founded upon tradition or a priori reason- ing. He had already reconnoitered on horseback a large part of the proposed zone of territory ; and he had acquired in Arizona and California a lield-experience equipping him for all the difficulties of the enterprise. More important still, he had evolved from personal observations and experience the one argument which, backed by his magnetic person- ality, could, and did, command the support of patriotic legis- lators.

The building of the first transcontinental railroads had been liberally encouraged as a measure of military and political ne- cessity, for the consolidation of the Union, and the final termi- nation of the minor Indian wars. It secured both these ends. California, which had been barely prevented from seceding in

Biographical Notice Of Clarence King, 631,

1861, when it was isolated in space and interest from the States of the East, lost both the power and desire for such schemes when the railroads tied it in a vital connection with the rest of the country. The Indian tribes could no longer make war. when the railroads enabled the army to concentrate rapidly at threatened points, and to make swift and thorough winter cam- paigns, not dependent upon grass for the cavalry horses or slow, wagon-trains for the conveyance of camp supplies from some far-distant base.

But still another step was needed to complete the great work of the railroads. It was not enough to traverse the vast wilder- ness of barren mountains and deserts, or to make its ways safe for the pioneer. The mountains and deserts must be trans- formed from barriers to be surmounted into sources of wealth and homes of industry, so as to make the nation, not two comi munities, bound together in artificial connection, but one con- tinuous empire, from sea to sea. To this end the first requisite was to disclose the natural resources of the region between the Missouri and the Sierra Nevada — above all, its mineral re- sources ; for mining is the great pioneer industry, in the train of which all others follow. There never was, and probably there will never again be, such an amazingly rapid conquest of a continent as has been effected in forty years under what may be called the American system — the mining prospector going in the van as an irregular scout ; the disciplined army of rail- road-builders, surveyors, geologists and engineers close behind ; and the representatives of agriculture, manufactures, education, political organization, social culture and religion following so swiftly that the whole army might almost be described as an advance without a rear-guard.

This spectacle, now familiar to us, was foreseen by a young man who could say, and make men believe, " The mountains of our great vacant interior are not barren, but full of wealth ; the deserts are not all desert; the vast plains will produce something better than buffalo, namely, beef; there is water for irrigation, and land fit to receive it. All that is needed is to explore and declare the nature of the national domain."

And the same man could speak from personal knowledge of the region to which he called attention, and could appeal to the Engineer Department of the Army for testimony as to his

682 Biographical Notice Of Clarence King.

ability to carry out the work he proposed. The result, sur- prising then, and surprising still, was a generous appropriation by Congress for the geological survey of a strip of 100 miles on each side of the 40th parallel of latitude ; in other words, of the belt containing the first Pacific railroad. The work was to continue three years, and was placed expressly under the charge of Clarence King (then 25 years old), subject only to the administrative control of Gen. A. A. Humphreys, Chief of Engineers of the U. S. Army — a brilliant topographical en- neer as well as military commander, who appreciated the young explorer too thoroughly to interfere with his plans and methods.*

The difliculties and dangers of this work were not small. King's party, reaching California by way of Panama, spent three months in preparing its . outfit and reaching its field. Many times it seemed as if portions of the scheme must be abandoned ; but the leader's enthusiasm, energy and resource inspired his associates, and made them invincible. At the end of three years the work was not finished ; but its success and value had been so brilliantly demonstrated that the period was extended to seven years, by the unsolicited action of Con- gress.

An incident reported by Mr. Emmons illustrates the cour- age and decision which belonged to King as one " born to command."

In 1868, during his field-work in ISTevada, annoyed by fre- quent desertions from his cavalry escort — a small detail, under the charge of a sergeant — King resolved to make an example of the next case of the kind. The occasion was provided by a specially " bad man," who, while the party, engaged in their day's work, were absent from camp, fitted himself out with equipments belonging to the Survey, and " struck " for the Pacific coast, nearly twelve hours before he was missed. King and the sergeant started at once in pursuit. At about sunset

The first legislation of Congress did not cover all this. It was simply a brief provision in an appropriation- bill, authorizing the application of certain unex- pended remainders of former appropriations in the continuance of surveys for a transcontinental wagon-road. Upon this modest beginning, King won both pop- ular and legislative recognition of his great enterprise.

Biographical Notice Of Clarence King.

of the next day the trail was seen to be heading for a natural pass in the next range (one of the short meridional ranges characteristic of Nevada). Leaving the trail, King and his companion, by a hard night-ride, made a detour over the moun- tain, and reached at sunrise the western outlet of the pass. Here he saw the fugitive's horse picketed near a willow thicket, which surrounded a spring, and in the middle of which the man himself was preparing his breakfast. King left his horse in the sergeant's charge and entered the thicket alone, with his " hair-trigger " Colt revolver. He afterward confessed that the situation required all his " nerve." The man, who was known as a desperate character, might have heard him coming and made preparation to shoot him at sight. But, after a minute of suspense, the climax was tame enough. The deserter, taken by surprise, was marched at the muzzle of King's pistol back to camp, and thence sent under guard to the military prison at Alcatraz — and there were no more desertions from that party. As for King's " nerve," it must have been little, if at all, disturbed ; for a man cannot long keep his finger still on a hair-trigger, if he is agitated !

The following account of another of King's adventures is given by Mr. Emmons, an eye-witness and a participant :

At the close of the field-work of 1871, King joined my partyi which had been engaged through the summer in the Uinta mountains, for a tour of inspec- tion along the northern frontier of that range. One day, as we were starting on an untried route across a piece of bad-land ' country, we spied, soon after break- ing camp, a grizzly bear in the distance ; and all hands at once gave chase. The bear at first disappeared in a region of sand-dunes, where the party got scattered. After some hours' trailing, King, Wilson and I, with a couple of soldiers, ran the trail into a typical net-work of bad-land ravines — a series of narrow gullies with perpendicular walls, quite inaccessible for horses. Tying the heads of our five animals together (for tliere wasn't a bush big enough to hitch them to), we followed the huge, human-looking tracks down one ravine and up another on foot, each with rifle in hand, and King in the lead. (There was a pretended, but not thoroughly heartfelt, emulation to occupy this place !) Not only were we con- stantly turning sharp corners, but the trail would run into caves made by changes in the course of the dry stream-bed, which would continue for some distance under a bend in the wall of a gully. The bear evidently ran into many of these caves, passing out of each at the other end. Finally, four hours after starting, we had run him to ground. We had found a cave with his track going in at one end and not coming out at the other ; and, by putting our ears against the bank, we could hear his labored breathing. The cave was unusually long— perhaps 30 or 40 ft. Its upper end, by which the bear had entered, was hardly more than a foot high ; the other opening was high enough to be entered on hands and

634 Biographical Notice Of Clarence King.

knees. The grizzly could be only heard, not seen ; but the sound indicated that he was nearer the upper end. Various attempts at dislodgment by smoking, etc, were unsuccessful ; and finally King, who had poked his head far enough in at the upper end to see in the dark, said he could distinguish the animal's eyes, and would go in and shoot him. So I was stationed at the lower opening in case the bear should come out that way, and King wriggled himfelf into the little hole at the upper end, until he was far enough in to raise his body on one elbow and put his rifle to his shoulder. Even then he could not distinguish the form of the bear in the darkness ; but he could see th gleam of its two eyes and feel its hot breath. Nor could he, at first, distinguish the sights of his rifle ; but, after accustoming himself somewhat to the darkness, he aimed as best he could between the eyes, and fired. The big soldier who had been stationed for that purpose behind him, at once dragged him out by the heels, and, in his excitement, kept on dragging long after he had got his man out. As a result. King's face was badly scratched in the sand. We were not absolutely sure that the bear was dead ; but, as there was no sound, I went into my end of the cave, and succeeded in getting a strap round its neck, by means of which and the combined and slow tugging of all hands we succeeded in dragging it into daylight. We then saw that King's ball had struck true, and penetrated the brain."

Mr. Hague contributes another reminiscence of King's self- possession under exciting circumstances. He was pursuing an elk, which finally turned and charged upon him. For a moment he was in considerable personal danger; but he came out victor, as usual. Listening, some time after, to King's story of the adventure, Hague said, " King, how did that elk look to you at the critical moment ?" " Like a first-class hat-rack on a mule !" was the instant reply.

It was in the first or second year of my field-work as United States Commissioner of Mining Statistics that I made the ac- quaintance of Clarence King. He was at that time camped with a small party on a terrace overlooking the Salt Lake Val- ley, and invited me to dine with him in his camp. I had just come from a very rapid examination of some of the canons in the Wasatch range, and he had been traversing the Uintah mountains further east. I remember the surprise with which I found him maintaining in the field, as far as possible, the decencies and elegancies of city life. Knowing of him as an explorer, hunter and athlete already famous, I could scarcely recognize my own expectation in the polished gentleman who, in immaculate linen, silk stockings, low shoes, and clothing without a wrinkle, received me at a dinner, simple enough in its material constituents, but served in a style which I had not found west of the Missouri. When I attempted to

Biographical Notice Of Clarence King. 63&

make fun. of him for " roughing it " in this way, he replied seriously : " It is all very well for you, who lead a civilized life nine or ten months in the year, and only get into the field for a few weeks at a time, to let yourself down to the pioneer- level, and disregard the small elegancies of dress and manners which you can afterwards easily resume, because you have not laid them aside long enough to forget them. But I, who have been for years constantly in the field, would have lost my good habits altogether if I had not taken every possible opportunity to practice them. We don't dine this way every day, but we do so whenever we can." I had abundant opportunity in after years to see King at work as well as at rest ; and I never knew a man more eager, tireless and reckless in field-work above or underground, while at the same time he maintained always the instinct and practice of refined manners. It was, indeed, al- most invariably his custom to have with him a personal attend- ant, who looked after his clothing, etc. One such, who was with him for years, came to be an invaluable assistant in geo- logical underground work, observing with great acuteness, although without scientific knowledge, indications which more learned men might have overlooked. I cannot forbear an an- ecdote told me by King of another valet of his, whose life was in his work, and who judged of all things in the world by their relations to it. At a gentleman's country-seat, with good servants, accommodations, ample facilities for blacking boots and brushing clothing, well-trimmed lawns and genteel society, he was in Paradise; but experience in the muddy or dusty wilderness half paralyzed his usefulness and wholly quenched his enjoyment. On one occasion, attended by this man only, King made his way to the Grand Canon of the Colorado, and stood for some time dumb upon its brink, overwhelmed with the vastness and the glory of the sublime and brilliant scene. At last it seemed to him that he must speak ; and, as he turned away, he said, " "Well, Joe, how does it strike you ?" " It is no place for a gentleman, sir!" was the reply.

The most famous incident of the Fortieth Parallel Survey was the exposure by King of the " Diamond Swindle " of 1872. A full account of this episode will be found in the Engineering and Mining Journal of Dec. 10, 1872, together with my own editorial comments, based upon private knowledge as well as

636 Biographical Notice Of Clarence King.

published reports. The whole affair reflected the greatest credit upon King's personal honor and loyal friendship — its most creditable feature being the way in which he managed the ex- posure so as to prevent further loss by innocent investors, and, at the same time, to avert unmerited disgrace from equally in- nocent promoters and experts. By a sudden and sensational disclosure he might have won cheap distinction for himself, at the cost of cruel injustice to others.

Returning to the more serious and permanent significance of this part of King's career, I quote from Emmons's article in the American Journal of Science the following excellent summary :

In recognition of the legitimacy of the public demand for a direct application of the results of government geological work, King pushed first to completion a scientific study of the ore-deposits of the region surveyed ; more particularly of the great Comstock Lode, whose enormous silver product was then disturbing the monetary system of the country. This work, written conjointly by himself and James D. Hague, appeared as early as 1870 under the title of Mining Industry. It was described by one of its most capable critics as by itself a scientific manual of American precious metal mining and metallurgy.' It is considered classic among works in its line, and has served as a model for similar monographs which have since been published under government auspices and done so much to raise the mining industry of America to its present high position.

'' In 1870 he discovered on the slopes of Mt. Shasta the first actual glaciers known to exist in the United States ; and in their study made observations that are credited with first suggesting the true origin of the kettle-holes and kames of New England. His later discovery in the summer of 1874, that a line of islands along the southern cosst of New England were a part of its terminal moraine, had much influence in inducing the later systematic studies of the Continental glacier.

" The field-work of the Survey was completed in 1873, but it was 1877 before the respective specialists had been able to work up the amount of material gath- ered, for it was one of King's fundamental principles that abundant collections should be made in the field to illustrate all the natural phenomena observed, and the lithological collections alone numbered about five thousand specimens.

'In 1874 he sent one member of his corps to Europe to study the. methods of European geological surveys and to obtain the best and latest geological literature, with which at that time American libraries were but scantily provided. He also instructed him to confer with Prof. Zirkel, then the greatest microscopical petrographer of the day, and to induce him, if possible, to visit America and study in the presence of the collectors their collection of rock specimens, for at that time no American geologist had any practical knowledge of this new branch of geology. From this visit resulted Zirkel' s volume on microscopical petrogra- phy, which marked the opening of a new era in geological study in the United States.

King reserved for himself the final summarizing of the work of his assistants and the drawing of general conclusions and theoretical deductions therefrom. This he wrote in the winter of 1877-78, and published in a quarto volume of

Biographical Noticb Of Clarbnce King. 637

more than 800 pages under the title of Sytiematic Geology. It has been character- ized as the most masterly summary of a great piece of geological field-work that has ever been written, and is used to this day by university professors of geology as a model for their advanced students.*'

After two years of field-work had demonstrated the practica- bility of making geological maps in the unsettled regions of the west, another survey was inaugurated by the Engineer De- partment under the direction of Lieutenant George M. Wheeler,, and the Hayden survey, already existing under the Department of the Interior, began the making of topographical maps as a basis for their geological work, and employed for this purpose the topographers of King's party after their term in that party had expired. These two surveys were not limited by law, like King's, to any particular region of the country, and each de- sired to get the most interesting part of the great west for its portion, partly because the survey of a district containing strik- ing natural phenomena or exceptional mineral richness would bring special fame to the conductor, but also because the re port of such a survey would constitute a very interesting public document, highly prized by congressmen for distribution ta their constituents, and would powerfully assist in obtaining further appropriations from Congress for that particular work. This rivalry in the field and in the capital became at last so intense that there was serious danger of a reaction in Congress,, cutting off all government aid for geological work. Mr. Emmons says :

''It was mainly through King's influence among the leading scientific men of the country and his tactful management of affairs in Congress that this crisis was averted. The question was referred to the National Academy of Sciences, and their recommendations, which were on lines laid down by him, were finally adopted by Congress, and on March 3, 1879, a law was passed establishing the United States Geological Survey as a bureau of the Interior Department. Presi- dent Hayes, after consultation with the best scientists of the country, appointed Clarence King as the first director of the new Bureau. King accepted the ap- pointment with the distinct understanding that he should remain at its head only long enough to appoint its staff, organize its work, and guide its forces into full activity. At the dose of Hayes's term he offered his resignation, but at the President's request he held over until after the inauguration of Garfield. The latter accepted it on March 12, 1881, in an autograph letter, expressing in the warmest terms his appreciation of the efficiency of King's service and his regret that he did not find it possible to remain longer in charge of the Geological Bureau.

638 Biographical Notice Of Clarence King.

" Brief as was the duration of his administration, his influence, being exercised at the critical period of the Survey's existence, left a lasting impress upon it He outlined the broad general principles] upon which its work should be conducted, and its subsequent success has been in a great measure dependent upon the faith- fulness with which these principles have been followed by his successors.

"Foreseeing the important part that the development of its mineral resources was destined to play in the future progress of the country, he judged that, while not neglecting the more purely scientific side, its work should be primarily de- voted to the direct application of geological results to the development of these resources. It has been because the people at large have realized its practical success in this line that the Survey has been more richly endowed, and thus better able to carry on its purely scientific work, than any organization of its kind in the world.

''King set the very highest standard for its work, and showed remarkable judgment and knowledge of character in his selection of the men who, in their respective branches, were best fitted to keep it up, as nearly as possible, to this standard. In his establishment of a physical laboratory for the determination of the physical constants of rocks, he took a step in the direction of the application of methods of exact science to geological problems so far in advance of the average standards of the day that its importance was not generally realized until long after.

''In all his after life he maintained a lively interest in the work of the Sarvey, and kept closely in touch with his successors in office, who frequently consulted him on important questions of policy.''

In another place, Mr. Emmons has spoken of the same period as follows :

"Although, owing to failing health, consequent upon the severe strain, both mental and physical, of nearly 20 years' strenuous work, he felt obliged to retire to private life in the second year of his directorship, he maintained the liveliest interest in the work and organization of the Survey up to the very last . . . His belief was that a geological survey of a great industrial country, while not neglecting the more purely scientific side of its work, should occupy itself pri- marily with the direct application of geological results to the development of the mineral resources of the country.

" Under his direction were carried on the examinations of the Comstock, Eureka, Leadville and other mining districts, whose importance is to be meas- ured not solely by the accurate information which they afforded of these particu- lar regions, but in far greater degree by their influence upon the whole body of mining engineers, in teaching them the practical importance of a study of the geological relation of ore-deposits.

"He also planned and supervised the collection of statistics of the precious metals for the Tenth Census, a work which has never been equaled in detail or scientific accuracy, and whose logical result was the annual collection of statistics of all the mineral resources of the United States, which has been carried on by the Geological Survey ever since the completion of the work of the Tenth Census."

The great success and popularity of the United States Geo- logical Survey has been due, without doubt, not only to the

Biographical Notice Of Clarence King. 639

liberal support of Congress, which King, more than any other one man, was able to influence, and to the wise organization and far-reaching plans which he impressed upon this institu- tion in its creation, but also to the ability, loyalty, activity and intelligent enthusiasm of the young men who received their training under him during the Fortieth Parallel Survey, and many of whom have since won high reputation by their inde- pendent researches. The recent volume on " Ore-Deposits," published by this Institute, bears testimony to the extraordinary advance in that department of geological science in which American observers may fairly be said to have taken the lead. No doubt they have won this distinction largely by reason of three exceptionally favorable conditions, namely : the vast and rich field for investigation offered by the territory of the United States ; the active development of this field by mining ; and the liberal expenditures, both State and Federal, which have been made for the study of economic geology. But these favorable conditions would have amounted to nothing without the men competent to take advantage of them, and the wise provision made for such investigations by the first Director of the U. S. Geological Survey.

King's important contributions to scientific literature, apart from his work on the two public surveys already mentioned, were very few. Probably the most important were his address at the Sheffield Scientific School, in June, 1877, on " Catastro- phism and the Evolution of Environment," and his paper on " The Age of the Earth," published Jan., 1893, in the Am. Jour, of Science.

The first of these was a quasi protest against the extreme uniformitarianism of the followers of Lyell, which he described (perhaps not quite fairly) as a theory that all geologic changes had taken place at " the harmless undestructive rate of to-day, prolonged backward into the deep past." I do not think Sir Charles Lyell would have controverted his main proposition that the evolution effected by the constant operation of known causes might, nevertheless, produce, and had in fact produced, more or less catastrophic changes. (To elucidate, by illustra- tions of my own, my notion of his meaning, I may cite the

640 Biographical Notice Op Clarence King.

eftect of gradual increments of heat upon ice, which, at a cer- tain point, suddenly turns into water, — or upon water, which likewise, at a certain point in the " uniformitarian " process, suddenly becomes steam. Or, as a general mathematical ex- pression of the same law, the curve corresponding to a given formula may be " uniformitarian " up to a given point, and may then, in accordance with the same formula, present an abrupt and complete change of direction.)

This general proposition was so true as to be almost trite ; but King gave it originality by illustrating it from the geologi- cal history of the American Cordilleran system, as developed by the Fortieth Parallel Survey.

As to " hypogeal fusion," King's hypothesis was that of a " critical " shell or couche surrounding (or forming the outer portion of) the permanently solid interior mass of the earth, and having a temperature which would fuse it, but that its fusion is prevented (i.e., its fusion-point is raised) by the pres- sure of the overlying rock. It would follow that when this pressure was diminished (as by rapid removal of the overlying weight) the rock thus relieved would become liquid, without necessary increase of its previous temperature, and local lakes of fusion would be thus created. Perhaps this ingenious suggestion might be called an application of TyndalPs well- known geyser-theory (which deals with the sudden vaporizer tion of a liquid) to a case of sudden transit from the solid to the liquid form. Unfortunately, Tyndall's theory is not so perfectly satisfactory as it once was ; and, besides, it includes a special sudden release of pressure (through the surface over- flow from the geyser-column) which is not conceivable as part of an analogous process affecting solid rock.

Since the only general agency by which superincumbent rock could be removed was that of denudation (upheaval, in most cases, would not do, because it is not altitude, but the amount of weight preventing fusion, which can be effective under King's theory), the criticism was at once advanced by some of us that this theory practically involved the assumption that denudation (a process scarcely conceivable as catastrophically sudden) can go on at a greater rate than the cooling of a given buried layer of rock — which we thought highly improbable, though (somewhat to our surprise) we could not prove it to be

Biographical Noticb Of Clarence King. 641

80. This objection King accepted with characteristic frank- ness— and relapsed into a significant silence, so far as public discussion was concerned. The secret (which he took no pains to explain to the scientific public) was, that he intended, before supporting his hypothesis by further argument, to provide him- self with the precise data as to the rate of cooling by conduc- tion through rock. We all knew (none better than he) that ice and congealed lava had lain for generations, perhaps for centuries, interstratified upon the slope of Etna; that "ice- caves " of the State of Washington showed how completely liquid lava could be protected from congelation by a rock-cover of moderate thickness ; that the immense lava-streams of the Sandwich Islands, similarly protected by their own congealed sheaths, ran quietly for long distances under the sea ; above all, that the interior cosmic heat of the earth is escaping at a very slow rate indeed. But, though all these observations point to an extremely small transmission of heat through rocks, nobody had fixed the actual rate of cooling for given condi- tions of weight and thickness of overlying rock.

In the chapter on Orography of his volume on " Systematic Geology " in the Fortieth Parallel series. King suggested his theory of the " critical shell," and said (p. 729), concerning it :

can plainly see that, were the critical shell established, its reactions might thread the tangled maze of phenomena successfully ; but I prefer to build no further until the underlying physics are worked out"

In pursuance of this conception, he established, in organiz- ing the TJ. S. Geological Survey, a laboratory for terrestrial physics, contributing from his private means to its installation and continuance. The subtle and brilliant investigations pur- sued in that laboratory by Barus and Hallock are a part of the history of science, and have secured for these skillful observers much honor, well-deserved.* But, unless I am seriously mis- taken, they have not yet determined for us the data which King desired as to the phenomena of the fusion and the heat- conductivity of rocks, under varying conditions of tempera-

For instance, I have high authority for saying that modern scientific pyrom- etry is now wholly based on the platinum-rhodium and platinum-iridium couples, first described in the monographs from this laboratory. See, also, as a specimen of delicate work in terrestrial physics, Mr. Barus' s paper, Traiw., xiii., 417, on Electrical Activity of Ore-Bodies." VOL. xxxin.— 39

642 Biographical Notioe Of Clarence King.

ture and pressure. At all events, I am not aware that King ever brought forward, in confirmation of his Sheffield address of 1877, any precise data of that kind. Meanwhile, the stand- point of his theory of a " critical shell " has been, perhaps, left behind in the progress of science — but on that head I need say nothing here. A man is not to be judged in the light of knowledge later than his own ; and I heartily adopt the lan- guage of Mr. Iddings, who, in his Origin of Igneous JRockSy says of Clarence King that, by the breadth of his treatment, and by better and fuller data, he advanced the problem of the origin of the various kinds of igneous rocks far beyond the point reached by any of his predecessors.

King's intuition was not at fault when he recognized the igneous rocks as those concerning which existing scientific knowledge and opinion was least definite, and American geol- ogy could furnish most valuable information.* Not only in- tercourse with his friend Richthofen, a famous pioneer-observer in this field, but also his own wide travels in all parts of the United States and Mexico, as well as Europe, the Sandwich Islands, and Cuba, had made him specially acquainted with volcanic and cognate phenomena, and their results ; and it was in this department of dynamic geology that he hoped to attach his name to a theory equally novel and fundamental.

So far as I am aware, the only result which he lived long enough to make known, of all this observation, study, prepara- tion and patience, was his paper on " The Age of the Earth," already mentioned. This, I believe, he considered as a begin- ning of a series of geological applications of laboratory results, which he hoped to make. Mr. Emmons summarizes the treatise as follows :

In 1873, speaking to the German Congress of Miners and Geologists at Vienna, President of the American Institute of Mining Engineers (and under the profound impressions made upon me hy a recent reconnaissance of the great lava-plains of Oregon, Washington and Idaho, including the remarkable series of successive igneous and aqueo-igneous deposits of Cape Horn on the Columbia, the bluffs of the Des Schutes, and the long basaltic cafion of the Snake river), I told them plainly that no true perspective could be established for geology until the message of America concerning the plutonic rocks had been heard, verified, and incorporated among the fundamental bases of the science. The proposition, thus somewhat loosely and oratorically announced, was recognized much more intelligently by King, and has been confirmed and illustrated by American geol- ogists, in the laudatory mention of whom, however, Vogt and Briigger of Norway must not be ignored.

Biographical Notice Of Clarence King. 643

''This was an attempt to adyance to new precision Kelvin's estimate of the earth's age deduced from terrestrial refrigeration. It consists mainly of a mathe- matical discussion of the earth's thermal age as determined from various postu- lates presented bj Laplace, George H. Darwin, and Lord Kelvin, and based on Barus's determinations of the latent heat of fusion, specific heat, melted and solid, and volume of expansion between the solid and melted state, of the rock diabase. This is followed by a critical examination of other methods of determining the earth's age — by tidal retardation, by sun-age, and by variations of eccentricity. After a careful scrutiny of all the data on the effect of pressure on the tempera- ture of consolidation. King concluded that, without further experimental data, ' we have no warrant for extending the earth's age beyond 24 millions of years,' an estimate which, as the result of a somewhat more extended discussion, was afterwards confirmed by Lord Kelvin himself {Smithsonian Ann, Rept.y 1897, p. 345).

I know that King considered the praise of this work by Lord Kelvin as one of the greatest honors ever bestowed upon him.

To general literature he contributed one delightful book, Mountaineering in the Sierra Nevada," and a few magazine articles. The book describes the scenery and the people en- countered by him in his early California experiences, and has never been surpassed as a gallery of vivid, graceful, and imaginative yet accurate sketches of nature and men. Bret Harte's admirable work is more romantic, more artificial, less delicately humorous, and less perfect in style. Indeed, con- sidering the relatively small amount of King's literary work, his mastery of style was wonderful. Perhaps the most perfect specimen of it was his fanciful sketch, " The Helmet of Mam- brino," published in the Century.

Doubtless one reason why he did not publish more was, as Mr. Emmons suggests, his fastidious taste, which led him to be dissatisfied with anything less than the best work. But this is not, to me, a full explanation. The possessor of such a gift of expression, and so rich a repertory of knowledge, and sugges- tions waiting for utterance, usually feels, also, the spontaneous impulse to make use of them. King was not an exception. He talked often of things he would like to write, and intended to write, some day. But he never found time for such labors, partly because of the exigent social demands made upon him ; partly because of the necessity for more active and arduous occupation, to which he was repeatedly, if not continuously, subject. A man can do literary work in his stolen leisure, and yet be a darling of society, shining brightly in the club and at

644 Biographical Notice Of Clarence King.

the dinner-table; or he may be active in business and pro- fessional engagements, and still keep enough time and strength for quieter pursuits. But he cannot be and do all three. King, especially, could not do this, because his brilliiant talk exercised and fatigued the same faculties as if it had been pen-work. If he felt the impulse of utterance he wore it out in talking, and often threw away upon the transitory entertainment of a few what might have been the enduring delight of a multitude. An instance was furnished by a dinner-party in Washington, just before the outbreak of the late Spanish war, at which King was present, and expressed with vivacity his views and expectations. He had lived in Cuba, was intimate with some of the patriot leaders there, and was thoroughly acquainted* with their plans and campaigns.* But he had also sailed the Pacific, and had an intelligent notion of the situation in the far East, of which few of us were specially thinking at that time. And his prediction was this : " If war is declared with Spain, the first thing to happen will be that George Dewey will go into Manila harbor and sink the whole Spanish fleet !" If he had put that day's talk in print, with what prophet's glory it would have crowned him ! Long after, he said to me, " I was a little startled to have the thing so quickly and completely come to pass ; yet I made the remark upon good reasons. I had lived with Dewey, and knew him well ; I knew where he was, and that he could not stay there after a declaration of war ; if he had to go somewhere, he would be sure to go where the Spanish fleet was ; and if he found it, he would sink it ! You see, the argument was complete!"

After all, the chief hindrance to King's literary activity was the necessity of earning money in his profession. Several times in the course of his life he suffered financial reverses, which forced him practically to begin over again, and to work as a mining engineer in the field — sometimes directing or ad- vising, sometimes valuing, sometimes buying and selling. Of three companies which opened respectively, — the Las Prietas

See his Forum articles, "ShaU Cuba be Free?'* and "Fire and Sword in Cuba."

Biographical Notice Of Clarence King. 645

mine, in Sonera, the Las Tedras, in Sinaloa, and the Sombre- rete, in Zacatecas, — he was the president ; and he was actively connected with the Richmond, at Eureka, Nevada, and other American mines.

On many occasions he was engaged as an expert witness in mining law-suits. I need hardly say that, while he was in the service of the United States, he gave no such assistance to pri- vate interests. Indeed, he was quick to perceive that the members of the public scientific surveys must be kept free from any suspicion of utilizing, for the benefit of any party smaller than the whole of a mining community, the knowledge gained in that capacity; and he exacted from every subordinate a pledge in this particular, corresponding with his own practice. But when not thus honorably bound, he repeatedly acted as ad- viser, or gave expert testimony, for clients. In this line, having both encountered Mr. King as an opponent and benefited by his assistance as a colleague, I may claim to be qualified as a critic of his work — or rather of his character, as shown by his work.

In the first place, he was, as I think an expert witness ought to be, an honest partisan. He did not carry to the witness- stand the doubts or uncertainties which he might have felt during his previous study of the case. He came forward with a theory already deliberately adopted, and for that theory (in the absence of new evidence disproving it) he was prepared to fight.

But this final tamper and attitude had the indispensable safeguard of an inexhaustible curiosity and candor in previous inquiry. I have known, in my time, many mining experts, and their personal methods of studying mining cases. But I never met Kings equal in insatiable desire to find out before- hand anything that anybody else knew or could know, whether it were relevant and important to the case in hand or not. I can remember him as going into a mine at early morning, taking his lunch with him ; coming out late in the afternoon ; bathing and dressing for dinner ; then, aroused by some casual table-talk, putting on his underground clothes again, and spend- ing the greater part of the night in the mine, just to " settle the point " — though the point was not perceptibly pertinent to the immediate case in which he was engaged.

646 Bioorapuigal Notice Of Clarence King.

In general, his exhaustive preparation and wonderful general knowledge, reinforced by his alert self-possession, ready wit and unfailing good-nature, made him a most effective expert witness and a terror to cross-examiners.

After retiring from the U. 8. Geological Survey, King spent three years (1882, '83 and '84) studying the geology of Scotland, Switzerland and Central Europe, occasionally visiting a mining district, like Bilbao, Rio Tinto or Almaden, and enjoying the social courtesies eagerly extended to him by the leaders of scientific thought, to whom his work had already made him known and his charming personality soon endeared him.

At a later period, after recovery from a severe illness, he spent a winter in Cuba, at the country-house of an American friend, and became deeply interested not only in the politics, but also in the general and economic geology of that island, examining particularly some of the important iron and man- ganese deposits of the Santiago district. He conceived a high opinion of the mineral wealth of Cuba ; and it was at least his dream, if not his definite intention and hope, that some day, when Cuba should be free, he would organize for that field, as he had done for a greater, a national geological survey.

I notice that Mr. Emmons* dates the final illness of Clarence Bang from an attack of pneumonia in 1901. From personal knowledge, I would put the beginning further back. During the spring of 1900 I was associated with King in the long trial of a case at Butte, Montana. The season was unusually mild, and the atmosphere of Butte unusually clear. Perhaps these balmy conditions tempted people to imprudent exposure. At all events, the town was afflicted with a veritable pestilence of pneumonia. In popular rumor the fatality was 90 per cent. ; in actual statistics it was 54 per cent, of all the victims attacked. Among the counsel, parties and witnesses in our case, or in their families, eleven died during the trial. King prepared himself with his usual pertinacity and industry, spending many hours underground, and taking prudent pre- cautions against chills; but he had an annoying hoarseness,

In his article in the Am, Jour. o/Scu, already cited, p. 287.

Biographical Notice Of Clarence King. 647

which he could not shake off. After giving his testimony he made a rapid trip to Salt Lake, for change of air and altitude, and in a couple of weeks returned, still uncomfortable, though not alarmed. But by that time the rest of us were anxious for him, and, against his will, made him consult a physician, who put him to bed instantly. This prompt measure saved him from a serious illness ; but the escape was a narrow one, as he . was willing to acknowledge after a few days' confinement. He was not allowed to take further part in the trial, and it was over before he was able to leave his room. When he told me that he expected to go to the Klondike that summer, I felt a thrill of apprehension, and ventured a remonstrance. But, like all habitually healthy people, he thought nothing more of a temporary illness, once it was over ; and to the Klondike he went, with the seeds of pulmonary trouble already sown in him. And after the exposures of the Klondike trip he had a second and severe attack of pneumonia, brought on in 1901 by a fresh exposure during the examination of a mining property in inclement weather. From that time, the progress of tuber- culosis was rapid and irresistible. With superb courage and calmness he fought to the end the hopeless battle, seeking in vain, at Prescott and Los Angeles, cure of his malady, and finally returning from Southern California to Phoenix, Arizona, where he died without pain, December 24, 1901. With char- acteristic unselfishness he had refused all offers of companion- ship from friends or relatives, and made his last brave fight alone.

Many, no doubt, have had ampler and more continuous as- sociation with Clarence King than I enjoyed during the one- third of a century covered by our unbroken friendship. He was one who could pick up, after any lapse of time, however long, the associations and reciprocities of the past, and make the intervening separation seem not to have been at all. How- ever one might have been offended by his neglect to answer letters, or let himself be heard from in any way, five minutes of his presence was enough to show that the old friend, un- changed, had come to see the old friend, expecting an un- changed welcome. And what he expected, he received. I never heard of anybody who refused to forgive Clarence King

648 Biographical Notice Of Clarence King.

for neglect of conventional obligations — and I fancy all who knew him had occasion for such forgiveness. My own theory of the matter is, that he was so universally beloved, and re- sponded so easily to congenial companions, as to make it im- possible for him to keep up, by the usual means of visits, letters, etc., the innumerable ties which he thus formed, without sacri- ficing all the more serious labors and ambitions of his life. A man can forswear society altogether and do his life's work ; or he can give himself up to society and let his work go. King took a middle course, continuing to study and to labor, while he freely gave and received social enjoyment, but defied the en- grossing demands of formal etiquette. And " society " forgave him, because it could not have him on any other terms.

But perhaps it was given to me, in hours of unconstrained communion, to gain a deeper glimpse into his character than many days of mere superficial association could have given. And I found him clean to the bottom ; full of noble scorn for things trivial, vile and selfish ; alive to the highest ideals ; ready for the service of human needs.

It was in such an hour that he told me (veiling with a trans- parent whimsical humor of narration his earnest feeling) of his " Sunday-school " in London, where he used to meet, on Sun- day afternoons, the girls employed in Crosse & Blackwell's famous pickle-factory, and talk to them in fashion " not quite orthodox, perhaps, but then, again, not so awfully heterodox either !" — and how, finding his Sunday-school utterly ignorant of the beauties and joys of green grass and fiowers, he organ- ized an excursion for them, securing, by unlimited use of his aristocratic acquaintances, unprecedented privileges for it, so that his delighted proteges, conveyed and convoyed by him on a special train, not only had afternoon tea on the lawn in Wind- sor Park, but the dear old Queen herself came out of the palace, walked among them, and accepted a cup of tea from a proud member of the company ! King's witty account of his " happy hen-party " I cannot undertake to reproduce. But there was for me something dearer and deeper in it than its sparkling surface.

Few among those who have achieved distinction in the labors or the literature of science have also impressed upon their gen-

Biographical Notice Of Clarbncb King. 649

eration a vivid sense of their own personality. In the majority of instances, I think, such men have hid themselves in their work, sacrificing to it the varied enjoyments and associations through which they might have become better known to their contemporaries. Perhaps we might say that, in this age, sci- entific distinction must be won, as a rule, in some specialty, and at the cost of an exclusive devotion to that one department ; so that the great specialist, however versatile he might have be- come, if all his original endowments had been utilized, is at last, to the eyes of men, simply the impersonal representative of one idea or sphere. On this point we have the frank, pa- thetic confession of Darwin, that many aesthetic faculties and tastes, once his, became atrophied in the course of years de- voted to a single study. After the death of such a man, a sympathetic biographer may lift the veil and show to all what had been known before to few, — his personal traits and charms ; thus filling up with detail and color the hard, meager outline of him presented by his special work alone.

Clarence King did not thus sacrifice himself to his work. His buoyant personality dominated his whole career. Gay, versatile, debonair, irresistible, gentle, honorable, " tender and true," he was greater and dearer than his work. We shall have, as we have had, many prophets and pioneers of science ; but the King is dead — and there is no King to follow !

The following list comprises the principal published works of Clarence King :

Mountaineering in the Sierra Nevada," Boston, 1870.

"Mining Industry" (by James D. Hague, with geological contributions by Clarence King), vol. iii. of the Fortieth Parallel Reports — Government Printing Office, Washington, 1870.

" Active Glaciers within the United States." Atlantic Monthly, March, 1871.

" On the Discovery of Actual Glaciers on the Mountains of the Pacific Slope," Am. Jour. Sci., 3d Ser., vol. L, p. 157, 1871.

Notes on Observed Glacial Phenomena and the Terminal Moraine of the N. E. Glacier," Proc. Boston Soc. Nat. Hist., vol. xix., p. 60, 1876.

'Paleozoic Subdivisions on the Fortieth Parallel," Am. Jour. Sci., 3d Ser., vol. xi., p. 475, 1876.

Notes on the Uinta and Wahsatch Banges," Ibid., p. 494.

" Gatastrophism and Evolution," Am. Nat., vol. xL, p. 449, 1877.

"Systematic Geology," vol. i. of the Fortieth Parallel Keports, Government Printing Office, Washington, 1878.

650 Mining And Metallurgy At St. Louis World'S Fair, 1904.

"First Annual Report of the U. S. Geological Survey," Govemment Printing Office, Washington, 1880.

"Physical Constants of Rocks," U. S. GeoL Survey, 3d Ann. Report, p. 3, Government Printing Office, Washington, 1883.

"Style and the Monument," North Am. Review, Nov., 1885. (An article on the proposed Grant monument — anonymous, but known by friends of Mr. King to have been written by him. )

" Artium Magister," North Am. Review, Oct, 1888.

"The Age of the Earth," Amer. Jour. Sci., 3d Ser., vol. xlv., Jan., 1893.

"The Helmet of Mambrino," Century, p. 164, May, 1886.

"The Biographers of Lincoln," Century, p. 861, Oct., 1886.

"The Education of the Future," Forum, p. 20, March, 1892.

"Shall Cuba be Free?" Forum, p. 60, Sept, 1896.

"Fire and Sword in Cuba," Forum, p. 31, Sept, 1896.

Mining and Metallurgy at the St. Louis World's Fair, 1904.

BY PROP. JOSEPH A. HOLMES, ST. LOUIS, MO. (New Haven Meeting, October, 1902.)

The public is already familiar with the general fact that the scope and the financial resources of the approaching St. Louis- World's Fair are much larger than those of any of the preced- ing great expositions ; and both the visitor and the exhibitor when he comes to St Louis in 1904, will find it to be a real World's Fair, with exhibits and visitors from every known country.

Passing over the subject, as to the general Exposition, with this brief statement, I ask your attention to the consideration of a few important facts connected with the proposed mining exhibits at this Exposition. First of all, I may say that read> ing- and writing-rooms and library facilities will be furnished in the Mines Building for miners and mining engineers, and it is expected that when they visit the Exposition they will make these rooms their headquarters, and give the Chief of the De- partment and his assistants an opportunity to extend to them such courtesies as may be possible.

One of the exhibits in the Mines Department will consist of models and maps arranged to show the nature and extent of the mining operations in the United States at the time of the purchase of the Louisiana Territory in 1803, the event which

Mining And Metallurgy At St. Louis World'S Fair, 1904. 651

this Exposition commemorates. Of course, the industry waa then in its infancy, and the exhibit will necessarily be a small one. But since that time the United States has expanded underground almost as rapidly as it has above ground. It will be one of the great purposes of the Mines Department of the Exposition to show the nature and extent of this under- ground expansion, the equipment used in the mining opera- tions of to-day, and the metallurgical equipment and processes employed in the preparation of these mineral products for use by the people at the present time. Hence, the larger part of the exhibits in the American section of the Mines Department will be arranged so as to show the condition of the mineral in- dustry as it is to-day, and to illustrate its development during the intervening century. Of course many of these processes are so complicated and extensive that they can only be repre- sented by models and photographs, but all those which will lend themselves to treatment on a small scale will be shown at the Exposition in actual operation.

The exhibits of the Department will be divided into five groups, and these, in turn, are divided into fifty-three classes.

In the first of these groups it is intended to show equipment and processes connected with the working of mines, ore-bed& and stone-quarries. This will include equipment and methods used in prospecting for mineral deposits ; in making geological surveys ; in testing and assaying ores and other mineral sub- stances; in opening up, timbering, draining and ventilating mines ; and equipment for underground and aboveground trans- portation for ores.

The second of these groups of our classification will contain the collections of rocks and minerals, supplemented by exhibits illustrating the equipment and processes employed in preparing this material for actual use, and the products into which they are manufactured. Another group of exhibits will illustrate the whole subject of metallurgy, including the processes em- ployed in the transformation of these ores into their respective metals. In this, special prominence will be given to the metal- lurgy of iron and steel ; but prominence will also be given to- other important metals, and to the alloys of these various metals. Some of these exhibits will also endeavor to illustrate general foundry equipment and processes, and the processes

€52 Mining And Metallurgy At St. Louis World'S Fair, 1904.

connected with the use of electricity, gas, petroleum and other fuels in metallurgical operations ; and the equipment and pro- cesses connected with electro-plating, and other uses of elec- tricity in mining and metallurgy.

The two remaining groups of exhibits will include models, maps and photographs of mines, quarries, metallurgical and mining equipment, and the literature relating to quarrying, metallurgy, geology, etc.

The exhibits of specimens of rocks and minerals and ores illustrating the resources of this and other countries will be made largely under the official Government and State Com- missions, as heretofore ; but we shall require that every such specimen brought into the Mines Building at the Exposition must be accompanied by labels, maps, photographs, charts, -etc., giving accurate information as to the real ore or mineral- deposits which such specimens represent; and, in order to ac- complish this result in the most satisfactory manner, we are endeavoring to secure the active co-operation of the State and other local geologists and mining engineers with the State Commission in the collection and preparation of these ex- hibits.

The exhibits illustrating the metallurgical and other processes through which these metals and other minerals and stone are utilized will be made largely by individuals and private cor- porations, and we are endeavoring to have these as complete and elaborate as possible. Thus, for example, in connection with the lead industry, all the important processes will be shown from the crushing of the ore down to the manufacture of shot. For zinc, copper and gold, the metallurgical processes will be shown in practically the same degree of completeness. In the iron and steel industry, the more important actual metallurgi- cal operations cannot, of course, be shown, but these will be indicated by specimens, models, photographs, charts, etc., in a way becoming this greatest of our mineral industries.

The Mines Building at the Exposition will cover about nine acres; and it is so well arranged that practically the entire space, except that occupied by walls, is easily available for ex- hibits. It promises to be the most beautiful building on the grounds, and its location is in every way satisfactory. On one side of it, for a considerable portion of its length, the ground

Elimination Of Arsenic, Antimony And Bismuth. 65S

rises gently to a height of 40 ft. above its floor; and under- ground tunnels can be run into this hill to illustrate methods of tunneling, timbering, and the underground transportation and handling of ores in the most satisfactory manner. On the ground adjacent to the building is an additional area of ten acres for such out-of-door exhibits as will illustrate the drilling of oil-wells, the operation of stamp-mills, the hydraulicking of placer-deposits, etc.

In brief, as far as this may be possible of attainment, these exhibits are all planned and will be installed with a view of having them tell the whole story as to our mineral resources ; bow they are mined and brought to the surface ; how they are transformed by the metallurgist and manufacturer, and thus made ready for use by the people.

In the mineral and mining exhibits from each foreign coun- try, we are asking that special prominence shall be given to those branches of mining industry which are prominent in that special country, and also those which are largely exported from that country. And in the metallurgical exhibits from each of these countries, we are asking that each country's ex- hibit shall show especially the processes and products in those branches of metallurgy which are being largely promoted and developed in that country.

The Elimination of Arsenic, Antimony and Bismuth from

Copper.

By Allan Qibb, Mount Perry, Queensland, Australia.

(New Haven Meeting, October, 1902.)

The ores of copper are usually associated with minerals con- taining arsenic, antimony and bismuth. Whatever the means adopted for extracting the copper, these metals are usually found, to a greater or less extent, in the product. There is, however, usually some elimination in the various metallurgical operations to which the ores are subjected, and some attempt is made here to determine the degree to which this elimination is effected.

654 Elimination Of Arsenic, Antimony And Bismuth.

The degree, as well as the cause, of the elimination varies -considerably with the amount of impurity in the material under treatment, and the results given here can only be taken as con- -clusive in the case of such materials as have come under the writer's observation. The conclusions have, however, been drawn from the study of large quantities of materials that may be considered as fairly typical.

Elimination may take place in the smelting operations by ficorification, volatilization, or, under special treatment, by pro- cesses of concentration. Owing to the great variety of mate- rials that are treated in economical metallurgy, it is rarely pos- sible to obtain exact weights from any particular operation. It is, consequently, a matter of some difficulty to obtain data that will show how elimination has taken place. In much of the following work the writer has had to be satisfied with deter- mining the relative elimination of the impurity under consid- eration. In only a few cases have I been able to obtain exact weights, etc., of products.

Roasting of Copper-Ores.

This operation may be carried on in heaps or stalls, when the ore is treated in the form of lumps, or in closed furnaces into which the ore is introduced in the form of a powder. The ac- tion of heat and air in the elimination of the elements under consideration appears to be the same in either case.

Arsenic, when present in sulphides, in arsenides, or in the metallic state, volatilizes at incipient redness as arsenious sul- phide or as metal, or it is oxidized to arsenious oxide, which is readily volatilized. Arsenates, mainly those of iron and copper, are formed by the oxidation of both elements of the metallic arsenides, and by the action of atmospheric oxygen and arsenious oxide upon metallic oxides. These salts, as well as any similar compounds that may be present in the ores under treatment, are fixed at the highest temperatures. Ar- senates may possibly be reduced by the action of sulphur and sulphides with the production of sulphides, arsenides or arsen- ites, and under the action of air these may be volatilized. But as this reducing action is in every case endothermic, it is very unlikely to take place under the conditions of low temperature and oxidation pertaining to the roasting operation. In point of

Elimination Of Arsenic, Antimony And Bismuth, 655

fact, the arsenic remaining in calcined ores consists largely of metallic arsenates.

Antimony is, to a great extent, similar to arsenic in its occur- rence in copper-ores, and also in its deportment when subjected to the action of heat and air. It volatilizes as a sulphide and as metallic antimony, but to a less extent than the corresponding compounds of arsenic. Metallic antimonates are probably formed in greater proportion to the amount of the impurity present than in the case of arsenic, and are fixed at all temper- atures.

Bismuth may be present in the metallic state or in sulphides, arsenides and antimonides. The metal and sulphides are vola- tile at the roasting temperatures, but much less readily than in the cases of arsenic and antimony. The minerals containing bismuth are readily oxidized to fixed compounds.

The roasting of copper-ores preparatory to smelting is always incomplete. Arsenic, antimony and bismuth may remain in the roasted product in the same combinations in which they occurred in the ores, a<;companying the fixed compounds that are formed during the operation.

The degree of elimination of these impurities in this opera- tion varies, necessarily, with the minerals in which they occur, as well as the copper-ore, and the conditions under which the operation is carried on. The following analytical data show the elimination from fairly typical ores when roasted in heaps and in closed furnaces.

Roasting Ores — Elimmation of Arsenic Antimony and Bismuth.

Raw Ore.

Calcined Ore.

RliTnlnAtlon

Total Percentage of Elimina- tion.

Per Cent. Actual.

Percent.

Relative.

Copper=100.

Per Cent. Actual.

Per Cent.

Relative.

Copper=100.

per 100 Of Copper.

Copper.

Arsenic

Antimony... Bismuth

Copper

Arsenic

Antimony... Bismuth

656 Elimination Of Arsenic, Antimony And Bismuth.

'So. 1 was a cupreous iron pyrites which was roasted in heaps and subsequently smelted in a blastrfurnace. No. 2 was a dressed ore containing copper, mainly in the form of copper pyrites, with smaller proportions of bornite and copper-glance. It was calcined in a reverberatory furnace.

In both ores, as is usually the case with sulphuretted ores, the proportion of arsenic is much larger than that of either an- timony or bismuth. From the table it will be seen that the elimination of arsenic is considerably greater, in proportion to the original amount contained, than is the case with either an- timony or bismuth.

Smelting Calcined Ores.

In this operation there is a distinct difference in the action of the reverberatory and the blast-furnace. The atmosphere in the reverberatory furnace is always oxidizing, and the reac- tions that take place in melting calcined ores are (except in so far as they form a continuation of the roasting operation) only such as take place between the constituents of the ore. Ar- senates heated strongly with silica are decomposed with the formation of metallic silicates, oxygen and arsenious oxide. Silica usually being present in the furnace-charge, arsenic may be eliminated by this action. Ter-sulphides of arsenic and bis- muth remaining in the calcined ore may be volatilized when heated to the smelting temperature. Arsenates or antimonates and fixed oxides of these elements combine, in notable propor- tions, with the slag-forming elements. Arsenic and antimony are often present in considerable proportions in the slags from reverberatory furnaces smelting calcined ores.

The conditions are different in the blast-furnace when smelts ing calcined ores, as the gases are of a reducing character. The larger part of the arsenates and antimonates are probably reduced to arsenides and antimonides. These combine with the sulphides of iron and copper, forming the regulus, while the resulting slags contain none, or only minute traces, of these elementB. Arsenic and antimony are probably volatilized as sulphides, but the greater part of both is concentrated in the resulting regulus. Bismuth and its sulphides, which may be reduced from the oxides and sulphates formed in the calcina- tion, are volatilized in considerable proportions during the

Elimination Of Arsenic, Antimony And Bismuth. 657

smelting operation. Furnace slags, whether produced in the blast-ftirnace or in reverberatory furnace are, so far as they have come under the writer's observation, practically free from bismuth. The following analytical data were obtained from cal- cined ores and the regulus resulting from smelting in the two classes of furnaces.

Smelting Calcined Ores in Reverberatory Furnaces — Elimination of Arsenic, Antimony and Bismuth.

Caloined Ore. Coarse MeUl.

ElimlnaUon per 100 of Copper.

Total

of Elimina- tion.

Per Cent Actual.

Percent. p-nnt Per Cent.

Relative, i SSSS ' ReUtive.

Copper=100.| Actual. ctopper-lOO.

Copper.

Arsenic

Antimony... Bismuth

100.00 , 37.0 100.00 0.96 , 0.132 1 0.357 0.236 ' 0.037 0.10 0.094 ' 0.028 , 0.075

1 1

"62.8"

Copper.

Arsenic

Antimony... Bismnth

100.00 35.28 100.00 2.29 1 0.185 0.524 0.347 0.04 , 0.113 0.097 0.025 0.070

Smelting Calcined Ores in Blast-Furnaces — MiminatUm of Arsenic Antimony and Bismuth.

Calcined Ore.

Percent STiiifJ?*- Per Cent

[Copper. 10.60

Arsenic 0.102

Antimony... I 0.026