Bulletin of the United States Geological Survey--Methods and Costs of Gravel and Placer Mining in Alaska

Name: Bulletin of the United States Geological Survey--Methods and Costs of Gravel and Placer Mining in Alaska
Author: Purington, Chester Wells

Purington, Chester Wells

Bulletin of the United States Geological Survey--Methods and Costs of Gravel and Placer Mining in Alaska

Purington, Chester Wells · 1905 · Historical

Washington, D. C, February 15, 1905. Sir: I transmit herewith a report by Mr. C. W. Purington on Methods and Costs of Gravel and Placer Mining- in Alaska

Public-domain full text preserved in the Mountain Man Mining Library. Original source: archive.org.

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Bulletin No. 263

Series A, Economic Geology, 55

Department Of The Interior

United States Geological Survey

CHARLES D. WALCOTT, Director

Methods And Costs

Of

Gravel And Placer Mining In Alaska

By

Chester Wells Purington

Washington

Government Printing Ofeice

Digitized by the Internet Archive in 2013

http://archive.org/details/bulletinofunited263puri

4 Contents.

Hydraulic mining — Continued. page.

Storage reservoirs 127

Pipe lines 128

Giants and nozzles 134

Sizes and prices 134

Methods of piping to sluice 136

Bank-head water 137

Duty of miner' s inch 138

Handling of bowlders 141

Sluices and gold-saving appliances in hydraulic operations 142

Tailings 150

The hydraulic elevator 151

Dredging 157

Introduction 157

Description of operations 160

Cost of dredging 1 67

Notes on dredging, by J. P. Hutchins 1 73

Sluices and gold -saving appliances, excluding hydraulic operations 190

Cleaning, retorting, and melting 205

Fineness of gold 207

Labor 21C

Lumber and fuel 21S

Timber 211

Coal 21,

Roads and road building in Alaska 21'

Introduction 21'

Cost and method of constructing highways 22!

South Coast province 22 .

Atlin district and Yukon Territory 22

Central Yukon province 22

Seward Peninsula province 22

Freight rates 22

Freight rates from the States 22

Local freight and passenger rates '. . . 22

Customs regulations 24

Telegraph rates 24

Tables of distances and prices of mining supplies

Legal conditions in 1904 21

Introduction 211

Application of present mining law to Alaska 2!'|

Discovery 21 1

Subsequent annual labor I

Boundaries 2

Bibliography : 2

Index 2 1

Illustrations.

Page.

Plate I. Rock-cut on Miocene ditch line, Seward Peninsula 13

II. General map showing area traversed 14

III. A, Churn drill mounted on scow, Snake River; B, Winter dumps,

Klondike 40

IV. A, Set-up of boxes for shoveling-in, American Creek; B, China

pump, Klondike 56

V. A, Yukon placer miner; B, Dam for booming, American Creek... 58 VI. A, Steam scraping on Walker Fork, Alaska; B, Dumping to sluices,

Klondike -. 62

VII. A, Derricking at Fairbanks, dumping; B, Derricking at Fairbanks,

loading 64

VIII. A, Skids for derricking; B, Derrick bucket 66

IX. A, Dumping bucket; B, Rough bed rock and bowlders piled in

pit 68

X. Plan of derricking plant, Ophir Creek, Seward Peninsula 70

XI. A, Steam shovel, Anvil Creek; B, Steam shovel, Bear Creek, Klondike 74

XII. A, Stationary washing plant, Klondike; B, Cocoa matting and expanded metal riffle 80

XIII. A, Adit to drifting operations; B, Thawing ahead of shovel, Eldorado Creek 84

XIV. A, Old drift timbers in hydraulic pit, Klondike; B, Application of

the steam point in open-cut work 86

XV. A, Drift mining on Fairbanks Creek; B, Hydraulicking, Silver

Bow basin 92

XVI. A, Topography, South Coast province; B, Treadwell ditch line at

Lawson Creek, Douglas Island 114

X VII. A, Pressure box in Treadwell ditch; B, Method of staying pressure

box, Silver Bow basin 116

XVIII. A, Flume of Jualpa Mining Company, Silver Bow basin; Typical

South Coast topography, Gold Creek 118

XIX. A, Typical interior topography, Mastodon Creek, Birch Creek district; B, Ditch building, head of Nome River, Seward Peninsula. 120 XX. A, Miocene ditch, Glacier Creek; B, Flume of Hot Air Company,

Ophir Creek 1 24

XXI. A, Pier for trestle, Hot Air ditch line, Ophir Creek; B, Small storage dam, Bonanza Creek, Klondike 1 26

XXII. A, Settling pond, Anvil Creek, Seward Peninsula; B, Pipe Yun\

Pine Creek, Atlin, British Columbia 128

XXIII. A, Set-up of hydraulic pipe line, McKee Creek, Atlin, British

Columbia; B, Hydraulic pit, Klondike benches 132

6 Illustrations.

Page. Plate XXIV. A, Bed-rock sluice, Klondike benches; B, Blocks of frozen

gravel in hydraulic pit, Klondike 136

XXV. A, Sluice below elevator, Ophir Creek; B, Retaining dams,

Bonanza Creek, Klondike 148

XXVI. A, Hydraulic elevator in pit, Glacier Creek; B, Gravel in pit,

Glacier Creek 152

XXVII. A, Hydraulic elevator; B, Open cut worked by tramming to

bed-rock sluices 154

XXVIII. A, Single-lift dredge, 40-foot ground at Atlin, coarse gold; B,

Buckets, Atlin dredge 160

XXIX. A, Trommel and gold-saving tables, New Zealand type, Bonanza Creek, Klondike; B, New Zealand dredge, Bonanza

Creek, Klondike 162

XXX. A, Dredge of New Zealand type at Oroville, Cal., Leggett No. 3;

B, Buckets, dredge at Council

XXXI. A, Digging on spud; B, Stacker, New Zealand type of dredge

California No. 1 176

XXXII. Buckets: A, California No. 3; B, El Oro; C, Indiana No. 2; D,

Lava BedsNo. 2. 17m

XXXIII. A, Lower tumbler, California No. 3; B, Digging ladder at low

angle, Oroville, Cal 18(

XXXIV. A, Uncompleted belt stacker, Oroville, Cal.; B, Troughed belt

stacker, Oroville, Cal 18' J

XXXV. A, Oroville, Cal., practice in pond dredging; B, Pilot house,

upper deck, starboard side 18' ]

XXXVI. A., Winter dumps, showing previously erected sluice boxes,

Klondike; B, Mud box, used in string of boxes 19! J

XXXVII. A, Mud box on Gold Run, Klondike; B, Oroville riffles used

at Atlin, British Columbia

XXXVIII. A, Road in Fairbanks district; B, Road in Atlin district, British

Columbia 22

XXXIX. A, Ogilvie Bridge, Klondike River; B, Six-mule team drawing

8,000 pounds, Klondike 22

XL. A, Six-horse team drawing 3,300 pounds, Cleary Creek, Fairbanks; B, Creek topography, Fairbanks district 22

XLI. A, Pack train, Birch Creek district; B, Trestled flume in Eagle

district 22.

XLII. Topography, Seward Peninsula province 24

Fig. 1. Map showing American Creek drainage, Eagle district A-

2. Map of part of Birch Creek district

3. Map of part of Fairbanks district

4. Map of part of Seward Peninsula

5. Klondike rocker

6. Small steam scraper, Klondike

7. Set-up of scraper, Klondike

8. Bottomless steam scraper

9. Plan of track-and-incline system

10. Plan of steam-shovel operations, Anvil Creek

11. Plan of steam-shovel operations, Galesburg, 111

12. Pulling-up device for steam shovel

13. Rig for small drifting operation

14. System of opening drift mine

15. Hidden Treasure system of timbering drift mine

'"

Illustrations. 7

Page.

16. Plan of drifting operations on Solomon Hill, Klondike 85

17. Details of steam point and erosshead 90

18. Dawson self-dumping carrier 94

19. Map of portion of Juneau district, Alaska 114

20. Section of ditch in construction 122

21. Map of Miocene ditch 124

22. Method of nesting made-up hydraulic pipe for shipment 129

23. Various forms of pipe fittings 131

24. Device for reenforcing joints of pipe 132

25. Device for setting pipe by battering 132

26. Pipe wrench for setting and upsetting hydraulic pipe 133

27. Bracing hydraulic pipe on steep slope , 133

28. Method of bracing giant 136

29. Method of hydraulicking frozen gravel, Klondike benches 137

30. Sluice box used on McKee Creek, Atlin, British Columbia 143

31. Tightener used in making sluice boxes, Atlin, British Columbia 146

32. Rail riffle used in Seward Peninsula 149

33. Hood in head box of tail sluice 153

34. Angles for upper tumbier 179

35. Tailings well stacked 183

36. Tailings poorly stacked 183

37. Spud digging 185

38. Spud digging 186

39. Spud digging 187

40. Mud box 192

41. Modified Caribou undercurrent 194

42. Improved Hungarian riffle used at Oroville 195

43. " Kulibinka ' ' sluice and undercurrent used in Siberia 196

44. Modified Siberian pan for handling clayey gravel 198

45. Pole riffle fitted with knives for breaking clay 200

46. Riffle to hold divided sheet of quicksilver 202

47. Special block riffle for saving porous gold 202

48. Iron grate riffle, Seward Peninsula 203

49. Method of constructing road over frozen muck, Klondike 225

Tables

Page.

1. Average capacity and cost of gold gravel mining and operations in north-

western America 38

2. Rainfall in Alaska 48

! . A verage dates of last spring and first fall frosts 49

4. Average dates of opening and closing of the Yukon 49

5. Table of temperature 49

Table of stream volumes 52

7. Table of stream grades along important sections of their courses, Alaska.. 54

8. Table of ditches and flumes 104

9. Data necessary in ordering hydraulic pipe 130

10. Water required and effective work of double-jointed hydraulic giants, with

table of sizes, volumes and heads of water, weights, and prices 135

11. Duty of miner's inch in northern placer mining 139

12. Water required in hydraulic elevators 155

13. Fineness of gold by districts and creeks 207

14. Scale of wages in Alaskan camps, including Dawson, Yukon Territory, and

Atlin, British Columbia 211

15. Cost of firewood and flume lumber in Alaskan camps, including Dawson,

Yukon Territory, and Atlin, British Columbia 215

16. Cost of road construction 221

17. Ocean freight and passenger rates for 1904 from Seattle to Alaskan coast

points, including lightening when necessary 230

18. Through freight and passenger rates for 1904 from Seattle to interior Yukon

points, via White Pass route, rail and water, season June 15 to September 15 233

19. Through freight and passenger tariff for 1904 between San Francisco,

Seattle, and Yukon, Koyukuk, and Tanana points via St. Michael 234

20. Local freight and passenger rates for 1904 via river steamer from Dawson

to points on Yukon and Tanana rivers 235

21. Local passenger and freight rates on the Tanana 235

2. Local passenger tariff on Koyukuk River, 1904 236

3. Packing rates from Rampart, Alaska, to creeks, 1 904 237

1. Freight rates from Circle, Alaska, to creeks, winter and summer 238

5. Freight rates from Fairbanks, Alaska, to creeks, winter and summer 238

ii. Local freight and passenger rates in Seward Peninsula, with rates of lightening cargo at Nome 240

7. Distances between towns in Alaska, excluding Seward Peninsula 246

8. Local distances between points on Seward Peninsula 247

9. Distances from main supply points in Alaska to neighboring creeks 247

30. Prices of mining supplies in the North 249

Letter Of Transmittal

Department of the Interior,

United States Geological Survey,

Washington, D. C, February 15, 1905. Sir: I transmit herewith a report by Mr. C. W. Purington on Methods and Costs of Gravel and Placer Mining- in Alaska, and recommend its publication as a bulletin.

Placer mining1 in Alaska is affected by conditions which are not combined in any other field familiar to American miners. Hence new methods of operating must be substituted for those which are employed in other regions if the greatest success is to be obtained. In too many cases this fact has not been sufficiently recognized and many enterprises have therefore failed when they should have succeeded. These failures have tended to deter capital from entering a field which still presents many opportunities for profitable investment. Some of the factors which increase the cost of production of placer gold in Alaska, such as high rates for transportation, are changing for the better; others, such as the inadequate water supply and low-stream gradients which prevail in many localities, are permanent and must be met by properly applied methods of exploitation. It is these facts which led to the investigation so successfully carried out by Mr. Purington, the results of which are here presented.

It is believed that this report will stimulate the mining industry by making available, in compact form, the accumulated results of the experience of mining men in this field and by directing attention to those mining methods developed in older districts which appear to be adapted to the conditions prevailing in Alaska. While many of the figures presented, showing cost of labor, transportation, and fuel, are subject to fluctuation, with a general tendency to decrease, yet, as a comparative study of mining methods, this report will form a valuable permanent contribution to mining literature. Very respectfully,

Alfred H. Brooks, Geologist in Charge Division of Alaskan Mineral Resources. Hon. Charles D. Walcott,

Director United States Geological Survey.

Methods And Costs Of Gravel And Placer Mining In Alaska.

By C. W. Purington.

Introduction.

Owing to the fact that numerous requests have been received by the Geological Survey during the last three years for information regarding the cost of operating gold-bearing alluvial deposits in Alaska and the best means of working the claims in the various districts, the preparation of a report embodying such information, in so far as is possible from data at present obtainable, was. decided on.

I was requested, in the spring of 1904, by Mr. Alfred H. Brooks, geologist in charge of the division of Alaskan mineral resources, to proceed to some of the most important placer fields of Alaska during the open season of 1904 and to collect data for an economic report. I was asked also to visit the neighboring British fields of Atlin and Klondike for the purpose of comparison. Mr. Sidney Paige was assigned as my assistant for the field and office duties, and has rendered most efficient aid during the entire progress of the work.

In the north the Juneau, Atlin, Klondike, Birch Creek, Fairbanks, and Seward Peninsula districts were successively visited, and on the return a short stay was made at the gold-dredging field of Oroville, Cal. (See PI. .II, p. 14, general route map.) Data concerning the districts not visited — the Porcupine, Chistochina, Cook Inlet, Fortymile, and Rampart, and remote parts of Seward Peninsula — have been collected from reliable sources, especially from members of the Geological Survey who have made investigations in those portions of Alaska.

Itinerary.

A start was made from Seattle May 26. Five days, from May 30 to June 3, were spent in the vicinity of Juneau, Alaska, where the placers f Silver Bow basin and the power plant of the Alaska-Tread well mines

ere inspected. Six days, June 11 to 16, inclusive, were spent in the itlin district of British Columbia, where ten plants were visited on Pine, Willow, Boulder, Spruce, and McKee creeks and Gold Run. Twenty-two days, June 25 to July 16, inclusive, were spent in the Klondike district of the Yukon Territory, where 32 operations were

14 GKAVEL AND PLACER MINING IN ALASKA. [bull. 263.

visited on Gold Run, Sulphur, Upper Dominion, Bonanza, Eldorado, Hunker, Last Chance, Bear, and Gold Bottom creeks. Three days, July 17 to 19, inclusive, were spent in the vicinity of Eagle, Alaska, two operations on American Creek being visited. At Circle the regular route of transportation via Yukon River was departed from. On July 22 the party started west With a pack train and reached Deadwood Creek, in the Birch Creek district, on July 24. This day and the next were spent on Deadwood Creek, where 6 operations were inspected. On July 26, 5 operations on Mammoth and Mastodon creeks were visited. On July 27, 4 operations on Eagle Creek were visited.

The route was then pursued westward over the ridge trail to Fairbanks Creek. From August 1 to 5, inclusive, nearly all the operations in the recently opened Fairbanks district were visited, including 35 operations on Fairbanks, Chatham, Cleary, Twin, and Pedro creeks. On Fairbanks Creek a junction was made with Mr. L. M. Prindle's party, and it is due to the fact that the two parties worked together in the Fairbanks district that all the operations were visited in the few days available. During the few succeeding days as much information as possible was collected in the town of Fairbanks concerning the new gold finds of the Xanana, and my party then proceeded via the Xanana, Yukon, and St. Michael to Nome, arriving there August 20. From August 21 to September 4, inclusive, 21 operations were inspected on Anvil, Glacier, and Dexter creeks and Grass Gulch, and on Newton, Peluk, and Dry creeks.

On September 5 the party proceeded to Ophir Creek via Cheenik and Council, and from September 5 to 17, inclusive, inspected 29 operations on Ophir, Crooked, Warm, Gold Bottom, Penelope, and Big Hurrah creeks and Solomon River.

After returning' to Nome a week was consumed in completing at the offices of the mining companies the data already partially obtained on the creeks and in gathering all possible information concerning operations in portions of Seward Peninsula not visited. Xhe party arrived in Seattle October 2, and after a few days spent at Oroville, Cal., returned to Washington.

Field Methods.

Every operation in a district was not visited, but enough representative claims were examined to give a fair estimate of the cost, utility, and adaptability of each method of mining.

For assistance in obtaining the data necessary a blank, a copy of which is given on pages 17-20, was sent to all the placer miners of Alaska whose addresses were known. Xhis blank was accompanied by a circular letter, and in many cases by a personal letter, explaining the purpose of the investigation. Xhe fact that replies have been received from all parts of the Territory, in many cases from the most remote

Bulletin No. 263 Pl.

Showing Area Traverse!

n RiNGTON.] INTRODUCTION. 15

camps, shows that the mine operators take an interest in contributing ;o the preparation of the work in hand.

At the operations visited by myself or b}r Mr. Paige more detailed nformation was collected regarding costs, the handling of water, the jetting up of the plant, and the mechanical appliances. Forms 1, 2, 5, 4, or 5 (pp. 17-25) were used, according to the character of the )perations. Photographs were taken of all the operations visited. Dver 400 excellent photographs have been obtained by Mr. Paige, some of which are reproduced in this report.

In each district a study has been made of the water resources, the nost important factor in placer and hydraulic mining, and of the cost )f building and maintaining ditches, flumes, and storage reservoirs for lie purpose of using water under pressure. The important devel- >pment of ditch building in Seward Peninsula has been especially considered.

The quantity and quality of timber in the mining districts has been considered with reference to its use for fuel, for building flumes and sluice boxes, and for timbering drift mines. It is an unwelcome fact ihat the important placer districts of the Northwest do not contain a rreat amount of timber, and the mining communities of the interior nust use with discretion the scant supply of native timber at their command.

The questions of wages and cost of living have been considered from lie standpoint of both the laborer and his employer. Temporary conlitions govern wages in Alaska to a notable degree, and the table of vages applying in 1904 must be understood to have only present value. WThile the rate of pay for miners appears attractively high, the cost of iving and of transportation to and from the country must be considered, as well as the shortness of the active season and the low rate of winter wages. Alaska presents a small field for those whose aim is imited to the earning of a day wage. On the other hand, men who ire willing to work for wrages during the summer, and actively and ntelligently prospect during the winter with the money so earned, lave always the chance of finding and locating a pay streak for themelves. The main object has been the determination of the cost and most xpeditious means of getting out the auriferous material — gravel, and, or bed rock; of the cost of obtaining its valuable contents; of he best methods of h}7draulic mining; of the cost of removing overurden under each set of conditions, and of handling the tailings; of he capacity and cost of installing mechanical methods; of the cost, apacity, and adaptability of the methods employed to thaw frozen ravel; and of the most feasible method of mining in little-developed districts.

16 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Care has been taken to avoid the publication of figures which were accompanied by the request that they remain confidential. It may, in general, be said that the detailed data furnished have been used mainly for the purpose of compilation, and have not been herein specifically transcribed.

In addition to matters relating directly to the operation of placer mines, attention has been given to means and cost of freight and passenger transportation. Whoever contemplates engaging in mining in the northwest portion of America, especially in the interior Alaska country, can not devote too much attention to the study of the cost of transportation of supplies. For the benefit of those who must depend on local supply points in the north for their needs, a table is given showing present costs, at each principal point, of the articles most necessary to the miner.

As regards transportation facilities, care has been taken to collect and embody in this report all available data and statistics relating tq the construction of wagon roads in the Northwest. The neighboring fields of British Columbia and the Yukon Territory, in Canada, have afforded excellent opportunity to obtain costs and methods of road construction applicable to the Alaska interior. Recommendation regarding the most practical and serviceable routes for road construe-] tion in Alaska have been made in a previous report Mr. Alfred HJ Brooks/' The need of these roads can not be urged too strongly, and the expenditure of $1,000,000, as suggested by Mr. Brooks, would be! man}7 times repaid the resulting development and increased gold production. Already over 300 miles of wagon road have been built. by the Canadian government in the Yukon Territory and the Atliqi district of British Columbia, while over 600 miles of sled roads have been made in the Yukon Territory. The fact that in the summl wagons and vehicles of all descriptions, and even bic}Tcles, may be seen daily about Dawson, the Klondike creeks, and Atlin, in Britishl Columbia, while the winter roads in Canadian territory afford continuous easy routes for horse sleds down the Yukon to Dawson, is evi-i dence of the success of the Canadian road-building enterprise. Obi the other hand, there are in Alaska less than 50 miles of well-built' wagon roads, and these have been constructed by private enterpriser

No attempt has been made to give a detailed account of the topographic and geologic conditions in the districts visited, except where* such conditions have a direct bearing on the method to be employed in working the ground. The Geological Survey has already published many exceedingly valuable reports and maps, most of whicl : are distributed free of charge. A list of the Survey publications or Alaska is given at the end of this bulletin. Any prospector who h unprovided with the reports concerning the region in which he h working lacks an important part of his equipment.

a Placer mining in Alaska: Bull. U. S. Geol. Survey No. 225, 1903, p. 57.

purington.] CIRCULAR LETTER SENT TO PLACER MINERS. 17

It should be distinctly understood that the purpose of the expedition on which this report is based was not the sampling- of gold-gravel deposits. Sampling is the business of the mining engineer acting in a private capacity, and is neither practicable nor permissible for officers of the Federal Government.

Information concerning the tenor of the gravels worked was frequently given by operators whose claims were visited, and such statements have been considered in the estimates of the average tenor in gold of the gravels.

On the following pages are reprinted the circular letter and the forms which were sent to miners in Alaska:

Circular letter sent to placer miners.

Your kind cooperation is earnestly requested in the preparation of the report on the placer mining methods of Alaska, which has been undertaken by this Office under the supervision of Mr. Alfred H. Brooks, geologist in charge of division of Alaskan mineral resources.

Mr. Chester W. Purington has been detailed to investigate some of the principal placer districts of the Northwest during the coming summer, and will personally obtain as much information as possible. It being impracticable, however, to visit each operator, you are requested to assist in the preparation of this report by furnishing such data concerning your placer and the methods employed in operating it as are asked for on the accompanying blank form. The information furnished will materially aid the investigation and will insure the inclusion of all the districts in the final report, which it is expected will be distributed in 1905.

Methods of operating are improved and rendered more effective by a community of interest, and while data furnished by you and made use of in the report may assist some other operator, you also may derive benefit from it through the suggestions of others.

The results already attained in placer mining in Alaska and neighboring territory will be made use of for the purpose of outlining the most advisable methods to be followed in each of the principal placer districts. Especial attention will be given to gold dredging, hydraulic placer mining, the employment of elevators for obtaining artificial grade, and the determination of the best methods for the thawing of frozen gravel. A special feature of the report will be a comparison of costs of operation by various methods in all parts of the placer fields. It is evident that for carrying out the plan full data are necessary concerning the character of the ground, the local conditions, and the methods at present in use.

As the value of these reports depends largely upon the promptness of their publication, an early reply is earnestly requested. Please answer the questions on the schedule as far as possible. If you can not give the exact figures in all cases, make the replies as approximately correct as possible.

A copy of the report will be sent to each operator furnishing a statement, An addressed envelope is inclosed, which requires no stamp.

Form No. 1, sent to gold-placer miners of Alaska.

It is hoped that even in cases where the operator does not care to give full data concerning his property and operations he will furnish at least a part of the information requested. Very few of the facts obtained will be embodied directly in the report, but from the sum of them will be drawn conclusions and suggestions which it is hoped will be of value to the gold-mining community as a whole. Bull. 263-05 2

18 GRAVEL AND PLACER MINING IN ALASKA. [btjll.263.

1. What is the name and post-office address of firm, corporation, or individual

making this report?

2. What is the name of mine?

3. What is the location of mine, and in what district? (Note. — Give name by

which district is commonly known, such as "Birch Creek," "Ophir Creek," etc.)

4. By whom is the property owned?

Address:

5. By whom is the mine managed ?

Address:

6. (a) How long has the mine been operated, and what was date of opening?

(b) How many ounces of gold has it produced ?

(c) What was the gold worth per ounce?

7. What is the character of the deposit? (Creek, bench, river bar, seabeach, or

gravel plain.)

8. (a) How many acres does it contain?

(b) What are its approximate dimensions?

9. How many men are employed, and how much are they paid?

10. How many shifts are worked, and how many men on each shift?

11. Between what dates is gravel extracted?

12. Between what dates is it washed?

13. (a) Is there timber on the property?

(b) If so, how much, and of what kinds and average size?

(c) What does sawed lumber cost per thousand?

(d) Where is sawed lumber obtained?

14. (a) If gravel is in a stream bed, what is the grade of the stream per mile, in:

feet? (6) How many miner's inches or cubic feet of water are used in mining operations, and for how many months in the year?

15. How much, in dollars or cents, must the gravel contain per cubic yard to pay?]

16. How far below the surface does the pay gravel lie?

17. Will you please describe a section of the overburden, giving the succession and

thickness of turf, soil, sand, round or angular gravel, clay, etc.?

18. (a) Does pay lie directly upon bed rock? (b) If not, upon what does it rest,"

and what is beneath ?

19. How wide and thick is the pay?

20. Does it follow any definite channel or channels?

21. Is there more than one pay streak?

22. Is the pay gravel sandy or clayey?

23. (a) Is the gravel rounded or angular?

(b) What is the usual diameter of the stones?

(c) What per cent are over 6 inches in diameter?"

(d) What per cent are over 18 inches in diameter?

24. (a) Is ground frozen ? (6) If so, to what depth?

25. (a) Is bed rock hard or soft?

(b) What kind of rock?

(c) If slate, or thinly bedded rock, what is its angle or dip?

26. (a) Is bed rock excavated in mining? (6) To what depth?

27. (a) Do you get coarse or fine, flaky or shot gold? (6) Are nuggets found?

(c) Of what size?

Purington.]

(a)

(b)

(c)

(a)

(6)

(a)

(b)

(a)

(b)

Forms Sent To Miners. 19

Is gold smooth or rough?

Rusty or bright?

Flat or chunky?

Does nature of gold vary from grass roots to pay or in different parts of the pay streak?

If so, in what way? Please describe.

What amount of black sand is caught per cubic yard of gravel washed?

What amount of other materials?

Are other valuable minerals caught besides gold?

If so, what are they and in what amount? V2. Under which of the following heads do your operations come, and will you briefly describe the important features? (Operations: tundra, beach, creek, or bench mining. )

53. How many cubic yards of gravel are washed per day during the season?

54. How many cubic yards of overburden are stripped during the season?

Prospecting Ground.

1. Has ground been prospected by pits or by drill holes? (b) If by pits, what was the size and depth?

2. (a) How many were dug? (6) What did they cost?

3. (a) Did they need timbering?

(b) If so, how closely and how heavily?

4. If ground was prospected by drilling, what size, depth, and number of holes

were used?

5. (a) What was the cost per foot?

(6) What was the cost of equipment?

6. What difficulties were encountered?

7. How did the results from mining compare with the probable results as indi-

cated by prospecting?

Hydraulic Operations And Equipment.

1. How much water is used, and how is it distributed in the operations?

2. What is the length, capacity, and grade of ditches, and head and tail flumes?

3. What is the length and size of pipe lines, and of what is pipe made?

4. Will you kindly describe giants, as to size, make, capacity, effectiveness, etc.?

5. How are bowlders handled?

6. What and how much material is consumed, such as lumber, quicksilver,

powder, etc.?

7. What is the effectiveness of a giant upon frozen gravel?

8. How much gravel is moved in 24 hours, and what does it cost?

9. Are elevators used, and if so, what has been your experience with them?

10. How much water do they use?

11. Of whose make are they, and will you kindly describe them?

12. How large stones will they handle?

DREDGING. [Note.— If blueprints or photographs are furnished, they will be returned if desired.]

1. Will you kindly give a general description of dredge: Maker, type, size, esti-

mated capacity, cost, and some details of construction; especially of new features that have proved advantageous.

2. How are bowlders handled?

20 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

3. How deep will buckets or dipper dig?

4. What is capacity of buckets?

5. What are arrangements for moving dredge and holding it in place?

6. How is gravel sized?

7. Are plates or quicksilver used?

8. What is the life of wearing parts?

9. What kind of power and engines are used?

10. What fuel is used, and what is its cost?

11. What type of pumps are used, and what is their capacity?

12. How many cubic yards of gravel have been handled in a given time from past record?

13. What special difficulties are encountered?

14. What is cost of dredging under local conditions?

15. Is frozen ground encountered, and if so, how does dredger work in it?

In case of special operations not covered by the above summary, will you kindly give brief descriptions, especially of apparatus which has proved successful in handling placer gravel under northern conditions?

The following space is left blank in order that any special description of the property may be given.

You are requested to fill out this schedule as soon as possible and return in the inclosed envelope which requires no stamps.

Forms 2, 3, 4, 5, 6, contained the first thirty-four questions in form 1, and the questions in form 1 regarding prospecting ground. In addition the following data were asked for, a separate form being used according as the operations came under the heads of hydraulic mining, dredging, open cutting, or drift mining.

Form 2. — Hydraulic mining. Size of head-gate.

Dimensions, grade, length, capacity, and cost of head ditch. Cost of maintaining. Length of flume, if any.

Dimensions, grade, and size of lumber in bottom, sides, and battening; size an( length of posts and sills in head flume; number of collars to box.

Amount of wrestling and cost of same. Size of sills, posts, and stringers.

Is flume or ditch covered to prevent freezing? Describe method.

Number of relief gates in ditch line.

Are inverted siphons used? If so describe.

Amount of water available.

Size pressure box and size lumber used.

Head of water in feet.

Length of pipe line from pressure box.

If more than one pressure box or pipe line, describe.

Size, gage, cost, and nature of pipe employed.

Where obtained.

Kind of joints.

Kind and number of air valves.

Method of setting and upsetting pipe.

Size of pipe at giant or giants.

Is water diverted for other purposes beside giant?

If so, how much, and for what purposes?

Number and angles of elbows in main pipe line.

purington.] FOKMS SENT TO MINERS. 21

Size, make, and cost of giant or giants used.

Size nozzle used, with or without deflector.

How often is giant moved ?

What height of bank is operated on ?

What modifications adopted in system of piping owing to frozen gravel?

Does giant clean bed rock ?

If not, how is bed rock cleaned ?

How much gravel is moved per shift?

If bankhead or by wash water used, how much ?

How are bowlders handled, derricking or shooting?

Cost of handling bowlders.

Size, capacity, and cost of derrick and plant; cost to operate.

At what distance is head box of tail sluice from giant?

Dimensions, grade, and length of boxes in tail sluice.

Number of boxes.

Size of lumber in bottom, side, and lining boards.

Method of making sluice box, size of posts and sills.

Cost and time to make and put in place one box.

Life of lining boards.

Largest stones put through sluice.

Average cost of shooting bed rock to keep*sluice on grade.

Kind of riffles employed in the sluice — distribution.

Cost and life of same — preference of riffles.

Amount of quicksilver used.

Amount of quicksilver consumed.

Are undercurrents used ? Description, number, distribution, area of each, grade, results.

Per cent of gold saved in different parts of sluice.

Per cent of gold saved in undercurrents.

Per cent of gold lost.

Is gravel forked in the sluice ?

Is dump moved after leaving end sluice box ?

If so, by what power and to what distance ?

Are tailings impounded? If so, for what reason?

Method and cost of impounding.

Cost of breaking down, moving, and washing gravel per cubic yard.

Improvements contemplated or suggested.

If hydraulic elevator is used — make, size, weight, and cost of elevator-.

Depth of sump.

Effective lift of elevator.

Pressure necessary to obtain lift.

Size of throat, upcast pipe, and nozzle.

Weight, thickness, material, life, and cost of throat.

Method of joining upcast pipe.

Shape, material, and life of hood.

Largest stones handled.

Amount of water handled by elevator.

Amount of gravel handled by elevator.

Amount of water fed to nozzle.

Are auxiliary water lifts used?

Is any method beside piping used for feeding gravel to elevator? What method.

Describe sluice boxes before elevator, if any — number of boxes, grade, dimensions, riffles. 1 Describe tail sluice — length, grade, dimensions, riffles.

22 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263

Per cent of gold caught before and after elevator. Frequency, time, and cost of moving elevator. Difficulties encountered in its use.

Form 3. — Dredging.

Make and cost of dredge.

Estimated and actual capacity of dredge in cubic yards per twenty-four hours.

Is dredge in a river or in self-made pond?

Depth to which buckets dig, and height of bank above water level.

Where was hull constructed and of what material?

Feet of lumber in hull and cost of hull.

Dimensions and draft of hull, loaded.

Weight of machinery.

Power used, nature, amount, cost per day.

Height, size, method of bracing, and inclination of gauntrees.

Size, weight, position, and description of spuds, if used.

Size, number, position, and use of winch drums.

Position of lever house.

Size, number, and length of cables.

Does dredge dig on spud or head line?

Length, width, weight, material, of digging ladder.

Material and weight of tumblers.

Number, capacity, arrangement, weight, shape, and cost of buckets.

Material, life, and cost of bucket lips, pins, and bushings.

Are teeth used on any buckets?

How far in front of bow will buckets dig?

What size of stones are handled?

Do buckets clean bed rock?

Describe save-all, if used.

Is nozzle used for cleaning buckets?

Is trommel or shaking screen used? Preference.

Dimensions and life of trommel; size holes.

Is side chute used for large stones? Describe grizzly.

Is sluice box with auxiliary float used? If so, describe.

Is stacking ladder used? Length, how driven, steel-link belt, or rubber belt, width.

Height and distance from stern stacked.

Life, efficiency, and cost of stacker belt.

Treatment of fines, area, grade, and description of tables; kind of riffles most successful, amount of quicksilver used.

Is sand pump used? How often?

Clean up, how often? State method used and time consumed.

Size, make, and cost of pump used for supplying sluice water; height of lift.

Distribution of power; how much to each operation.

Size and capacity of boilers and engines or dynamos used; describe connections pulleys, and clutches.

Special difficulties owing to northern conditions.

Most frequent breakages.

What kind of ground does dredge work best in?

What kind of ground does dredge have most difficulty in?

If in pond, is water pumped in? How much? From what source?

Cost per cubic yard of digging and washing gravel.

n kington.] FORMS SENT TO MINERS. 23

Form 4- — Open cut {not worked by hydraulicking).

Depth of overburden stripped.

Method of stripping; by ground sluicing, hydraulicking, scraping, or booming. Cost per cubic yard of stripping; amount stripped in a given time. Source of water.

Amount of water in miner's inches. Length of ditch or flume and dimensions.

If water is pumped for sluicing, kind of pump used and cost of pumping per cubic yard of gravel handled. Dimensions and grade of sluice boxes and number used. Is mud box used? Dimensions. Disposal of large stones.

Size of lumber used; one or more strings of boxes. System of joining and setting up boxes. Kind of riffles, cost and life.

Dimensions of pit worked with one set-up, frequency of new set-ups, and time consumed in changing.

How is seepage water handled, by pump or drain?

Dimensions, length, grade, capacity, cost, and method of constructing drain; difficulties with drain. Is China pump used? Capacity; cost of pumping. Is power pump used? Capacity; cost of pumping. Describe system of dams, if used, method of construction and cost. How are tailings handled? If scraped by horses, cost of scraping. Per cent of gold saved in boxes, if known. The following special queries apply to open-cut work: If men shovel into boxes —

To what height do men throw?

Are platforms used?

Depth of ground shoveled in.

Amount of ground handled per shift per man in cubic yards. If horse scrapers scrape into boxes —

How many cubic yards per day will one team scrape into boxes?

Cost per day of team and driver.

Per cent of gold saved. If steam scraping is employed, in handling pay or tailings —

Describe plant and cost, cost of operation, capacity, and difficulties encountered.

Amount and kind of fuel used.

Number of men required to scraper.

Distance to which material is conveyed, and height elevated. If derricking is employed —

Describe capacity of plant, give cost, system of operating, amount and distribution of power and labor. If inclined track and car system is used —

Number and capacity of cars handled per shift; number and length of tracks in use.

Length of tram to bottom of incline.

Number of men to a car.

Length of incline and vertical height of dumping platform above bed rock.

Amount of power to elevate; system of elevating, automatic devices used. If steam shovel is used —

Size, make, capacity, and cost of shovel.

Power used, amount, and how generated.

Capacity of dipper.

24 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

If steain shovel is used —

Length of boom.

Weight of machine.

On track or skids.

Height of bank on which it will operate.

Does it clean bed rock, or do men clean bed rock after it?

Efficiency in digging the material at hand.

Does it dump into cars or sluice boxes?

Is conveying system equal in capacity to shovel?

Difficulties encountered.

Cost per cubic yard of digging.

Elevation to which gravel is hoisted in cars, power necessary for hoisting.

Describe track system for returning empty cars. If more than one of the above systems is in use for working open cuts on the same claim, give comparative efficiency and cost.

Form 5 — Drift mining. Dimensions of shaft. Cost and rate of sinking per foot. Is shaft timbered? Method of timbering shaft. Depth of shaft to bed rock. Unfrozen gravel —

Method of drifting.

What width of face is carried?

Are pillars left, what dimensions?

Height of posts, length of caps.

Are false sets used?

Method of filling or caving worked-out ground.

Are timbers recovered? Frozen gravel —

Rate and cost of sinking shaft by steam point.

Diameter of steam pipe entering shaft.

Length, diameter, and cost of points.

Pressure of steam, size of cross-head.

How far apart are points placed in face?

Is hot water used in starting points? Preference.

Horsepower per point.

How long are points left in face?

Cubic yards of gravel thawed by each point in given time.

System of mining and hoisting.

If gravel thawed by hot-water hydraulicking, describe method.

Size, capacity, and cost of pump.

Position of pump.

Temperature of and method of heating water.

Amount of water used.

Size nozzle used.

Cubic yards of gravel thawed per shift, Boiler — kind, make, cost. Kind, amount, cost of fuel burned per day. Distribution of power, to thawing, to hoisting and conveying. If gravel thawed by wood fires, describe method; give cost and capacity. Describe system of tramming, wheeling, or skidding to shaft. Describe system of hoisting. Is self-dumping carrier used? Kind, efficiency.

PUMngton.] GENERAL STATEMENT OF CONDITIONS. 25

To what distance and height above the collar of shaft does it transport the gravel?

Capacity of the plant.

Cost per cubic yard of mining, hoisting, and washing.

What area of ground is worked from one shaft?

If winter dumps are taken out and washed in spring —

Size of dump.

Method of sluicing.

Cost of sluicing.

Is dump rethawed?

Method and cost of rethawing.

Method of sampling dump, if any.

Acknowledgments.

Acknowledgments for assistance rendered and courtesies extended to the party would, if made in detail, fill a volume of themselves. I especially extend thanks to the operators of the Atlin and Klondike districts, and to the officers of the British Columbia and Yukon Territory administration for their hospitable reception to a foreign expedition. To the citizens of Alaska, in whatever capacity they may be employed, the party is indebted for uniform courtesy and assistance as well as unstinted hospitality. Without the cooperation of the miners the work attempted would have been impossible. I also wish to express my thanks to members of the Geological Survey who have furnished me with the valuable results of their Alaska investigations.

I wish to acknowledge indebtedness for assistance in preparing the description of ditch construction in Seward Peninsula to Messrs. G. A. R. Lewington, J. W. Davidson, A. H. More, and William West, of Nome.

Thanks are due to Mr. J. P. Hutchins, a gold-dredging engineer of long experience, who has contributed to the report an authoritative treatise on that subject.

The writer is indebted to Mr. Henry C. Perkins, of Washington, for many suggestions made during the final preparation of the manuscript, especially of that portion dealing with hydraulic mining.

General Statement Of Conditions.

Placer mining is that form of mining in which the surficial detritus is washed for gold or other valuable minerals. When water under pressure is employed to break down the gravel, the term hydraulic mining is generally employed. There are deposits of detrital material containing gold which lie too deep to be profitably extracted by surface mining, and which must be worked by drifting beneath the overlying barren material. To the operations necessary to extract such auriferous material the term drift mining is applied.

As nearly all mining in alluvial deposits comes under the head of gravel mining, that term has been adopted in the main for operations ijdescribed in the report of which the following chapter is a summary.

26 GBAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Occasionally, however, the precious mineral sought lies in a matrix of fine sand, or even entirely in the crevices of the bed rock on which the alluvial deposit rests. Obviously the term gravel mining does not cover the cases in which detrital gold is extracted from such matrices, and the general term placer mining0 has been, therefore, added in the title of this report for want of a name which shall include all operations considered.6 When in the subsequent matter the terms gravel deposit, gravel washing, and gravel mining are employed they must be understood, for the sake of brevit}T, to include the consideration of all classes of deposits in which gold of detrital origin is found.

The term " elluviaV has been applied to placer deposits formed by the rotting of rock in place to greater or less depth.6' Such deposits do not occur in the portions of Alaska visited, and may be excluded from consideration.

In regard to the valuable contents of the deposits, it should be stated that in all the cases here considered gold is the mineral sought. Platinum or any minerals of the platinum group have not been found in paying quantity in any part of Alaska. Alluvial tin has been found and mined in the western portion of Seward Peninsula. The deposits were not, however, visited by the present expedition/7

a Placer, according to a Spanish definition, is a place near the bank of a. river where gold dust is found. Lindley on Mines, sec. 419, makes the following comments:

"Dr. R. W. Raymond (Glossary of mining and metallurgical terms, Trans. A. I. M. E., vol. 9, p. J 164) defines the word placer as a deposit of valuable mineral found in particles in alluvium or diluvium, or beds of streams. He adds to the definition the statement that, by the United States Statutes, all deposits not classed as veins or rock in place are considered placers. As was said by the Supreme Court of the United States (Reynolds v. Iron S. M. Co., 116 U. S., 687-695; 6 Sup. Ct. Rep., 601), in distinguishing the two classes of deposits: 'Placer mines, though said by the statutes tol include all other deposits of mineral matter, are those in which this mineral is generally found in the softer material which cover the earth's surface, and not among the rocks beneath.' "

It is evident that the term placer mining as used in the present report covers a much more limited field than would be the case were the term placer used in its broad legal sense.

b The term alluvial mining, used in Australia, is not generally employed in the United States.

cEng. and Min. Jour., vol. 77, May 5, 1904, p. 722.

dSee the report of A. J. Collier (Bull. U. S. Geol. Survey No. 229, 1904) for an exhaustive account of the York tin deposits.

furington] GENERAL STATEMENT OF CONDITIONS. 27

Classification Of Alluvial Gold Deposits In Alaska.

The alluvial gold deposits of Alaska may be classified as follows: Classification of alluvial deposits in Alaska.

Creek placers . . Hillside placers

Bench placers

River-bar placers.

Gravel-plain (t u n r a) placers.

Sea- beach placers

Lake-bed placers.

Placers in, adjacent to, and at the level of small streams.

Placers on slopes, intermediate between creek and bench claims.

Placers in ancient stream deposits from 50 to 300 feet above present streams.

Placers on gravel flats in or adjacent to the beds of large streams.

Placers in the coastal plain of Seward Peninsula.

Placers adjacent to the seashore to which the waves have access.

Placers accumulated in the beds of present or ancient lakes; generally formed by landslides or glacial damming.

The methods of working the alluvial gold deposits are shown in the following table:

Methods of working alluvial gold deposits of Alaska.

Class of placers.

Method of working.

Creek placers

Hydraulicking.

Hydraulicking with hydraulic elevator.

Dredging.

Open cutting, separate stripping, and shoveling in.&

Open cutting, separate stripping, and horse scraping.

Open cutting, separate stripping, and steam scraping.

Open cutting, separate stripping, wheeling, and cable tram.

Open cutting, separate stripping, and steam shovel.

Open cutting, separate stripping, track and incline system.

Open cutting, separate stripping, track system, with hydraulic elevator.

Open cutting, separate stripping, track system, with derricking.

Open cutting, separate stripping, skidding, with derricking.

Shaft, drifting, and timbering.

Shaft, thawing, and drifting.

Hillside placers

By the same methods as creek claims.

a Charged to independent account. The stripping generally consists of frozen "muck," a mixture [>f silt and ice, which is ground-sluiced off. '. Includes rocker work.

o Detritus varying from 3 to 60 feet in thickness.

28 GRAVEL AND PLACER MINING IN ALASKA. [bull. 268.

Methods of working alluvial gold deposits of Alaska — Continued.

Class of placers.

Method of working.

Bench placers a

Hydraulicking.

Open cutting, separate stripping, and shoveling in.

Open cutting, separate stripping, and horse scraping.

Shaft or adit, drifting, and timbering.

Shaft or adit, thawing, drifting, little timbering.

River-bar placers &

Hydraulicking with hydraulic elevators.

Dredging.

Open cutting, steam shovel.

Gravel-plain (tundra) placers. c

Hydraulicking with hydraulic elevating.

Open cutting, separate stripping, and shoveling in.

Shaft, thawing, and drifting.

Sea-beach placers d

Digging shallow pits and shoveling in. e

Dredging.

Special devices.

Lake-bed placers

Hydraulicking.

a Detritus varying from 5 to 150 feet in thickness; in parts of Seward Peninsula to 230 feet.

b Detritus from 3 to 60 feet in thickness.

c Detritus from 15 to 150 feet in thickness.

d Detritus from 1 to 6 feet in thickness.

e The greater part of the gold from the beach sands has been obtained by rockers.

The above classes are based on operations actually seen during the season of 1904. Suggestions concerning the application of other methods to certain forms of deposits are given in the body of the main report.

In the districts (PL II,. p. 14) visited the deposits under exploitation as above classified were as follows:

Classes of deposits worked in districts visited.

Province.

District.

Class of placer worked.

South Coast

Juneau . .

Creek and lake-bed placers.

Interior

Atlin . .

Creek and bench deposits.

Creek, hillside, and bench placers.

Creek and bench placers.

Creek, hillside, and river-bar placers.

Creek placers.

Klondike

Eagle

Birch Creek

Fairbanks

CLASSIFICATION OF ALLUVIAL DEPOSITS. Classes of deposits worked in districts visited — Continued.

Province.

District.

lias of placer worked.

Seward Peninsula

Nome

Creek, hillside, bench, gravel plain, and seabeach placers.

Creek, hillside, and river bar placers.

Creek and river bar placers.

Council

Solomon

In the districts not visited the classes of deposits are as follows

Classes of deposits 'worked in districts not visited.

Province.

District.

Class of deposit worked.

South Coast

Porcupine

Nizina

Creek and bench placers. Do.

Chisna

Creek placers. Do.

Sunrise

Interior

Fortymile

Rampart

Creek and bench placers. Do.

Seward Peninsula

Topkok

Port Clarence ...

Fairhaven

Creek, gravel plain, and seabeach placers.

Creek and bench placers.

Do.

Kougarok

Do.

Methods Of Mining, And Conditions.

The mining of placer gold in Alaska is carried en for the most part during June, July, August, and September. The gold-bearing gravel mined during the remainder of the year by winter drifting does not exceed 15 per cent of the total annual amount extracted. The gold can not be washed from this gravel until the cessation of winter conditions liberates the water in spring for sluicing purposes. The sluicing of the "winter dumps" takes place during the latter part of May.

Many of the methods of mining have been developed within the last ten years to suit the unusual conditions existing in the northern gold fields. Gravel miners from other parts of the world found that in Alaska much of their previous experience proved of no special benefit. On the other hand, men without previous experience in mining, but possessing ingenuity, have occasionally adopted devices which have proved efficient and adequate to meet the northern conditions. Methods which had been condemned or tried with ill success in other bountries have given good results in Alaska, while the attempts to apply hydraulic or mechanical methods of established reputation elsewhere have frequently resulted in ignominious failure.

30 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Mining operations have been made difficult by the short available season, the lack of grade to the streams, poor water supply, poverty of timber resources, high cost of labor and transportation, concentration of gold on and in the bed rock, and comparatively large thickness of barren overburden, the frozen, or worse still, half-frozen condition of the gravel, lack of wagon roads, and inadequate mining and police regulations. In spite of these obstacles the wide and fairly uniform distribution of alluvial gold over large areas of Alaska, hitherto unexploited, the uniformly healthy and even enjoyable climate of the country, and the near proximity of the phenomenally rich gold fields of the British Yukon Territory, offer a certain justification for the present energetic prospecting and mining for gold over so extensive an area.

The main impressions derived from an inspection of the placer gold fields of the north are as follows: (1) Operations requiring the installation of expensive plants are frequently undertaken before adequate sampling of the ground has been done; (2) the methods of mining and conveying the auriferous material, while often leaving much to be desired from the standpoint of economy, are, in the main, developing along favorable lines; (3) the gold- washing and gold-saving appliances in use are, in numerous cases, inexcusably crude and inefficient.

The winning of gold from alluvial material is a business difficult both to learn and to conduct successfully. The careful miner, like the careful manufacturer, will give as much attention to one part of his business as to another, irrespective of the scale on which it is conducted. The extensive but not remarkably rich gold-bearing area of Alaska offers a field for men who propose to conduct their operations with energy, intelligence, and economy. To others it can afford only ultimate poverty and despair.

The South Coast province is characterized by heavy grades, abundant water supply, and good timber. Gold-bearing gravels are, however, distributed in small quantity and, however good the conditions for the installation of hydraulic plants, the province remains an unimportant producer of alluvial gold.

The Interior province promises to continue for many years a fairly important producer. Geographically considered, the phenomenal Canadian deposits of the Klondike come under this province. No gravels approaching the Klondike deposits in richness have been found on the American side, but a large area yet remains to be prospected.

Owing to the topographic conditions, low grades to creeks, and insufficient water supply at an available elevation, hydraulicking on any but the smallest scale is impossible. Many of the creek deposits are shallow, and, besides the primitive method of shoveling into sluice boxes so largely in practice, there is a considerable field for the installation of horse-scraping methods and the installation of simple mechan-

pr rim; ton.] METHODS OF MINING, AND CONDITIONS. 31

ical plants. Solidly frozen creek deposits exceeding 15 feet in depth can be most economically worked by drifting methods, as heretofore. Experience gained in the Klondike has been invaluable to the miners now developing the new Fairbanks field. There is room, however, for considerable improvement and redaction of expense in the methods employed.

The natural conditions prevailing in the Alaska interior gold field imply great age and erosion subsequent to any deposition beneath sea level. Topographic conditions exercise a remarkable control over the methods which can profitably be employed in gravel mining, and the prospective miner neglects a vital part of his preparation if he does not study the topographic features of a given district in detail before entering upon his operations. In California and Australia the geologic and topographic conditions favor the placer miner. In other countries, notably Siberia, Alaska, and the Yukon Territory, they are inimical to his success. In Alaska, as a rule, alluvial gold is almost entirely lacking where timber and water are plentiful, grades are steep, and the ground is unfrozen. Where gold is distributed in paying quantity, water supply is inadequate, timber is poor or altogether lacking, the miner must provide grade for his boxes and dump for his tailings artificial means, and must meet the formidable obstacle of solidly frozen alluvium. Bench deposits, where gravel can be moved on natural grade, occur in both the Forty mile and Rampart districts of interior Alaska, and have been made to produce a small amount of gold by the hydraulic method. Although it is not impossible that extensive and valuable bench deposits may yet be found, no deposit comparing either in extent or in richness with the famous " White Channel "of the Klondike has been discovered. In that portion of the Alaska interior lying between Circle, on the ukon, and Fairbanks, on the Tanana, the mountains rise to heights of rom 1,500 to 2,000 feet above the level of the streams, have rounded ops, and slope to the intervening valleys at angles which do not exceed 0 degrees, and often are not greater than 10 degrees. The streams nd valleys are on a gently descending plain, the grade of which does ot exceed 3 per cent, except in the upper one-half mile, and frequently not over 1 per cent. The mountains are referred to by the inhabiants as " domes," and the word fairly well describes them. They resent what corresponds most nearly to the upper segment of a great lipsoid except in places where the erosion has not been sufficient accomplish the obliteration of a still more ancient topography. jihis ancient surface, remnants of which are visible on the tops of the ighest mountains, was evidently a base-leveled plain, which was bproximately 2,500 feet above the present drainage plain. Although ae base-leveling is apparent to the eye, it is not evinced by the resence of rounded gravel on its surface. The lack of gravel is

32 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

accounted for by the fact that the second denudation has progressed for a great period, and the comparatively small amount or vertical section of gravel which existed subsequent to the elevation has been worn away.

In the Klondike recent streams have cut the old Pleistocene channels and have reconcentrated the gold.a The gold is about equally distributed in the old and in the new gravels. From the miner's standpoint, therefore, in the Klondike region there are two great classes of mining to be considered, namely, creek mining and bench mining. Outside of these two classes there is no mining in the Klondike of productive importance.

In the Birch Creek district, especially on Deadwood Creek, there is a very small amount of gravel in low benches which may be termed hillside deposits. The bulk of the mining, perhaps 90 per cent of it, is creek mining in its various forms. The terms bench deposit, hillside deposit, and the like are very loosely applied by the miners of the Northwest, and names are given to classes of mining to which they do not in any sense apply. This looseness of nomenclature is apparent in the Fairbanks district, where the term bench mining is applied on. Cleary Creek to operations in progress on the left bank of the stream at a place one-fourth mile above the junction of Cleary and Chatham creeks. But whereas the depth to bed rock in the main creek at this point is 18 feet, the depth on the so-called bench, 700 feet to the left, is 53 feet, and the level of the bed rock at which the gravel is found is practically the same. In the one case, namely, in the creek working, the overburden is 6 feet of muck, while in the "bench" to the left the overburden is over 45 feet of muck. The gently sloping side of the valley at this point is unbroken in outline.

Observations along the various producing creeks and from the hilltops have failed to distinguish any traces of bench topography in the Fairbanks district. Such placer mining as is carried on there comes under the head of creek mining. Geological evidence, however, suggests that bench deposits occur in the region lying between the Fairbanks and Rampart districts.

The methods applicable to bench mining at Dawson can not be used in the Fairbanks district, and all thought of applying them must be eliminated. The country being in every sense of more gentle topography, there is no room for the disposal of tailings from bench operations conducted by hydraulicking.

On Pedro and Twin creeks there are about 2 miles of ground less ! than 15 feet in depth which can be worked by open cutting, either by shoveling into sluice boxes or by derricking. On a portion of this ground it is possible to handle the water by bed-rock drain. Open cut mining has also been successful on Chatham Creek near its June

a See McConnell, R. G., Preliminary report on the Klondike gold fields: Geol. Survey Canada, 1900. a

>urington] METHODS OF MINING, AND CONDITIONS. 33

bion with Cleary. In all other portions of the district, so far as leveloped, drift mining according- to the Klondike system of thawing either by steam or hot-water hydraulicking, hoisting, and conveying by means of the self -dumping bucket on cable tram Avill probably be found most economical. I would suggest the method of underground tiot-water hydraulicking to the miners of Cleary Creek, while on Fairbanks Creek steam thawing appears to be advisable. The efficiency of the hot-water method as used in the Klondike is from 5 X) 6 cubic yards per horsepower generated in the boiler as against 3 cubic yards with steam. The method can, however, be applied only inder pertain favorable conditions.

In Seward Peninsula the greater rainfall, larger catchment areas it the heads of the long rivers, and the comparative cheapness with which ditches can be constructed has led to the investment of much capital in long water conduits. For example, a ditch system of 54 piles, built at an expenditure of $300,000 and costing $15,000 annually to maintain, supplies 2,000 miner's inches of water at 360 feet head for Pour months in the year. Approximately 200 miles of ditches have been built in various parts of the peninsula. Excavations of earthwork for ditch building in the peninsula average $1 per cubic }rard. Hydraulicking without the use of hydraulic lifts is economically impossible, except in extremely rare cases. Bench gravels in the front of Anvil Mountain, facing the sea, can be hydraulicked if water it a sufficient head can be obtained at an expense which is not prohibitive. The remarkable ancient gravel channel which cuts the southern portion of the peninsula from east to west, extending from Fish River along Casadepaga and Kuzitrin rivers to Port Clarence, lies at so low a level that the present streams have not cut through t to bed rock. Except where subordinate pay streaks exist in it ibove the present stream, therefore, the physiographic conditions will forbid its gravels being hydraulicked, while any other form of )pen cutting is manifestly impossible. It has been little explored, ,nd portions of it may be found rich enough to drift. Horse scraping, steam or power scraping, derricking, and the appliation of the mechanical shovel, accompanied in most cases by ground icing of the frozen muck, should receive consideration from the reek operators in Seward Peninsula, where the deposits are less tian 15 feet in depth. The low price of winter labor ($2.50 a day and oard) should permit of an increasing amount of winter drifting work iroughout the peninsula.

It will doubtless eventually be found that the power of water under

essure can be more successfully applied to the working of the

Jrerage Seward Peninsula placer by generating electric power and

{implying it to various mechanical devices. While it can not be denied I Bull. 263—05 3

34 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

that some of the hydraulic elevator installations are handling* the gravel at a profit, the contrivance is a makeshift, and its use forms no part of bona fide hydraulic mining.

Cost Of Mining.

The average value of fuels in Alaska as shown by present operations

is as follows:

Cost of fuels available for use in Alaska.

Bituminous coal, price at Nome $17 per ton (2,000 pounds)

Crude oil at Nome $3 per barrel

Spruce wood, average price in the interior $12 per cord

Experience in the Nome district indicates that California crude oil is the most economical fuel available in the southern part of Seward Peninsula. In the interior of Alaska the price of imported crude oil renders its use prohibitive for mining operations.

The recently exhibited tests of the adaptability and efficiency of gas-producing engines should receive attention from operators who] contemplate the installation of mechanical plants in any part of Alaska. There is no question that bituminous coal and lignite can be utilized for gas producers, giving proportionately better results than anthracite. An engineer operating a large pumping plant in the Klondike is of the opinion that even the poor spruce wood available for fuel im interior Alaska can be utilized in the gas-producer engine. The prejudices which exist againt the explosion type of engine in the United States are fast disappearing. They have been due to faulty construction of the engines and lack of knowledge of their principle among those who attempt to operate them. The present valid objections to installing gas and gas-producer engines are that these engines are undergoing a process of evolution, and the standard has not been attained. According to Mr. M. R. Campbell, the Government coaltesting plant at St. Louis has demonstrated that a gain of from 30 to 50 per cent of efficiency is attainable in the gas-producing compared with the steam-producing engine.

The comparatively low cost of California crude oil at Nome renders it a valuable fuel for the mining operations in that vicinity. The satitj isfactory results from one type of gas engine at St. Louis showed thai crude oils of widely varying composition can be used with a higher efficiency in generating gas for explosive engines than in generating 1 steam.

The purchase of water for hydraulic or sluice purposes is no general in Alaska. In Seward Peninsula water under natural hea( or pumped water is sold to miners to a limited extent. The averag< price is $1 per miner's inch, twenty-four hours' service, for wate under head and 50 cents for sluice water. The inch used correspond to 1.2 cubic feet per minute. This measure of the miner's inch i not accepted in this report. The miner's inch, according to its bes

Purington.

Cost Of Mining. 35

definition, which is followed in this report, corresponds for all practical purposes to a flow of 1.5 cubic feet per minute. Il is he hoped that if the Federal Government ever succeeds in establishing* an adequate code of. mining law for its possessions a definition of the miner's inch will be included.

The data in the table on page 38 were compiled from statistics collected during an inspection made in the summer of 1901 of the placer fields in Alaska, Yukon Territory, and northern British Columbia. Of the statements furnished by operators, only those which are considered reliable have been used. The work attempted had no relation to the sampling or valuing of mining properties, and time did not permit, except in a few cases, the measuring of the ground.

Owing to the varying conditions governing the cost of mining in the North, the Territory has been divided into three provinces. The South Coast province includes the Juneau, Porcupine, and Sunrise districts of Alaska. The Interior province includes the Atlin district of British Columbia, the Klondike district of Yukon Territory, and the Fortymile, Eagle, Birch Creek, Fairbanks, and Rampart districts of [Alaska. The Seward Peninsula province includes the Nome, Council and Solomon districts of Alaska.

The Nizina district of the South Coast province and the Port Clarence, Fairhaven, and Kougarok districts of Seward Peninsula, none of which were visited, are separately considered.

In preparing the sheet the working costs of 118 different operations

were first tabulated with reference to the method employed and to

situation. A second table was then prepared, in which the working

?ost was augmented by an amount per cubic yard based on allowance

or depreciation of plant. In general, six years was taken as the aver-

ige life of an individual property, and, except in the case of winter

rifting operations, one hundred and twenty days as the working sea-

on. It was then assumed that five annual payments are made to a

epreciation fund. The fund is equivalent to the cost of plant and

laintenance during the life of the property plus six years' simple

titerest on the investment at 5 per cent. Each annual payment was

ivided by the season's output in cubic yards, and the amount thus

btained was added to the daily working expenses, to get the total

ntput cost per yard, as far as possible. Prices paid for mining

roperty are not considered, as they represent an unknown factor.

In cases where expensive plants have been installed the amortiza-

on was calculated separately for each case.

In cases of shoveling-in and small mechanical plants, the installation

d maintenance cost was taken at an average amount for a group of

rations in each district. Where the operation implies an additional

ripping of overburden, which is always separately charged, the cost

distributed and added to the gravel extraction cost.

36 GRAVEL AND PLACEE MINING IN ALASKA. [bull. 263.

From the second table, where the costs were reduced to one figure for each district, a third (table 1, p. 38) was prepared, giving as nearly as possible the average cost for each of the seventeen separate methods considered in one or more of the three provinces. Where the operations from which the averages are derived exceed two in number, the fact is so indicated in the table.

The attempt has been made to reject figures which were evidently not representative. The final figure arrived at is not, however, always satisfactory. For example, under No. 5 (the method of working open cut by shoveling into wheelbarrows, wheeling to bucket, hoisting and conveying to sluice by self -dumping carrier on cable) $2.14 is representative for the Klondike, where seepage water is generally pumped from the pit, and many operators pump the water for sluicing. On the other hand, at a plant in the Birch Creek district of Alaska, mining only 22 cubic yards per day and handling the water by a drain, the cost of operation was $1.50 per cubic yard. In No. 13 (drifting solidly frozen ground, steam or hot- water thawing, hoisting and conveying with the use of the self -dumping bucket) the cost in the* Klondike is $1.95, while the higher figure given is arrived at by combining the expensive American camps of Fortymile and Fairbanks, where the cost is $4.63 and $3.56, respectively.

The high cost of hydraulicking with use of hydraulic lift in Seward Peninsula is caused by the difficulty of moving the gravel to thd bed-rock sluice a and the expense of the ditches and installations. Hydraulicking by means of water under natural head without the use of the hydraulic lift, or some other means of elevating the material, was not seen by me in Seward Peninsula. It is understood that a hydraulic plant is in successful operation at Bluff, 50 miles to the east of Nome, but there are no data at hand concerning it.

In the interior only bench gravels are hydrau licked. Steeper grades for sluices can be obtained, and the gravel is more easily moved. The high duty of the miner's inch in the Klondike is a large factor in bringing down the cost of No. 1 and No. 16.

It should be distinctly understood, if hydraulicking costs in the, interior appear attractively low, that the water supply is exceedingly; variable, and that no reliable estimate can be made beforehand of th( output of a given season's operations. Furthermore, while much o\A the bench gravel was originally rich, the pay streaks have beenlargeh drifted out, and the gold is not disseminated through the upper por j tion of the gravel to the extent that it is in the California grave banks. With regard to the pumping of water for hydraulicking pur poses, the practice can not be too strongly condemned. He is a bol< man who attempts it, and a singularly fortunate one who makes a finan cial success of it.

a This is caused not only by the exceedingly gentle grades of the streams, but also by the shingl character of the material handled.

Ptjrington.] Cost Of Mining. 37

Mr. Stephen Birch, operating in the Nizina district of Alaska, has courteously furnished for this report a summary of the costs of working placer ground on Dan Creek. These figures are given separately (p. 39) after the table, as they imply a total charge of invested capital in addition to working costs against one season's operations. They are worth the attention of prospective placer miners.

The cost of shoveling into sluice boxes in the remote parts of Seward Peninsula is at present from $3 to $5 per cubic yard. Some drifting operations have been carried on in the Kougarok and Fairhaven districts, on which figures are not at hand.

Dredging estimates furnished by reliable interior operators place the cost at 80 cents per cubic yard where gravel must be thawed by points ahead of the dredge. In Seward Peninsula it is estimated that if the property is sufficiently large for a ten-year life, a dredge can be operated at the cost of 30 cents per cubic yard. The field for dredges in placer mining in Alaska is extremely limited. In Seward Peninsula it is not impossible that some of the wide, shallow creek deposits will be worked successfully by means of the steam scraper. The cost of an experimental operation on Ophir Creek was reported to be under 20 cents per cubic yard.

The costs of operating by two mechanical systems in Seward Peninsula (involving the labor of men in shoveling into cars and tramming to the bottom of an incline, or into a bed-rock sluice leading to hydraulic elevator throat) are unfortunately not available for publication. The derricking system, No. 7, however, both in the interior and in Seward Peninsula, appears to be superior in point of cost to either of the above mentioned methods for working the average Alaska open cuts.

Frozen ground can not be attacked with success by the steam shovel. £ven where it digs the gravel successfully, if men follow it to clean bed rock by hand, the cost of operating is sometimes doubled. The steam shovel has, however, a field in northern placer mining.

Regarding mechanical operations in general, the important principle should be emphasized that the main expense is getting the material into the receptacle which conveys it to the sluice or washing plant. Tramming even for a long distance, and to a considerable elevation, idds a very small proportionate amount to the total cost of working, he establishment of a permanent washing plant, economically situated s regards water supply and dump, should be considered by every Uaskan miner who proposes working the shallow creek deposits which characterize that country. The isolation of the washing operaions, together with the adoption of the most economical system of ramming possible, will go far toward attaining the ends of adequate Irrade and room for tailings, which are the essential features of successful gravel mining.

Gravel And Placer Mining In Alaska.

[Bull. 263.

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purington.] PROSPECTING. 39

Mr. Stephen Birch, in a letter, gives the cost of placer work on Dan Creek, Nizina district, Alaska, as follows:

By ground sluicing through 20-inch flume: 6,803 cubic yards, $8,781.44, or $1,143 per cubic yard.

By use of 8-inch cotton pressure-hose and nozzle through 20-inch flume: 1,600 cubic yards, $1,457, or $0.91 per cubic yard.

By use of pick and shovel only, through 10-inch sluice box: 2,320 cubic yards, $5,100, or $1,875 per cubic yard.

A 273-foot tunnel, 6 feet by 6 feet, timbered: $1,017, or $3,725 per running foot, or 407 cubic yards of gravel removed, which costs $2.50 per cubic yard.

While the cost given above may seem high, it is because of the fact that it includes the cost of the tools and material now on hand, which were necessary to remove this gravel. Now, if this work is continued on for a number of years, the depreciation of the tools, etc., could by charged proportionately. These prices may not be a criterion for future operations in that country but were our first cost of operation, and any strangers going into that section of country would be apt to run up' their costs to these figures.

Prospecting.

Creek claims must be prospected by shafts, open cuts, or drill holes. Shafts are generally used and are most practicable for the Alaska miner. Open cuts are not practicable, except in very shallow ground. Drilling requires expensive equipment, the machines costing from $3,500 to $4,000 delivered in Alaska. As a means of prospecting auriferous gravels drilling is very satisfactory, but it is generally employed only in deep gravel beds, where dredging is contemplated. a In such ground excess of water prohibits the sinking of shafts. The cost of drilling with a 6-inch core churn drill is $2.50 per foot in California, and the tests of the deep gravels of the coastal plain have shown it to be practically the same in the vicinity of Nome, on Seward Peninsula. The cost of drilling depends on the price of labor and fuel, and will probably be about $3.50 per foot in the interior of Alaska. Unless contractors are found already equipped to do the work, drilling is more expensive than sinking pits, the cost of which varies from $3 to $8 in Alaska placer fields.

In the solidly frozen ground encountered in northern placers it is not necessary to sink the casing around the pipe as in ordinary drilling. In partly frozen ground, where the casing is necessary, much difficulty has been found in pulling it up. A driller of the churn type is shown in PL III, A (p. 40), mounted on a scow for prospecting the bed of Snake River, Seward Peninsula. b The results obtained by drilling when compared with actual tenor of the ground are variable.

jln testing the bed of Solomon River the results were found to run 7

.

a See a further description of prospecting by drill holes, by Mr. J. P. Hutchins, in the chapter on '.jjdredging, later in this report.

&For description of drilling operations in testing placer ground see Knox, N. B., Dredging and valuing dredging ground at Oroville, California: Trans. Inst. Mining and Metallurgy, June 18, 1903. Rilso Smith and Stebbins, Gold dredging at Oroville: Eng. and Min. Jour., Dec. 8, 1904.

40 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

per cent lower. In all parts of Alaska drill holes should be not less than 100 feet apart, on account of the unequal distribution of the gold. Geologic conditions at Oroville, or in other dredging fields of floodplain character, are radically different. There the ratio of holes is 1 to an acre or 1 to 5 acres.

Shallow bench gravels can occasionally be prospected by diverting a high stream or water from a ditch in a direction transverse to the gold-bearing channel. The water will ground sluice a trench to bed rock, thus crosscutting the ground. Such prospecting is done in the Fortymile district, and an example of it was seen on Gold Bottom Creek, in the Council district of Seward Peninsula.

Bench gravels covered by heavy overburden are usually prospected by drifts. Drifts require timbering and are more expensive than shafts, but give a more satisfactory test of the ground. In rich pay streaks the running of prospect drifts often more than pays the cost. Owners of claims sometimes get their ground partly prospected by letting out the right to drift to two or more men, who pay a royalty on the gold they take out. In the Nizina district a 20 per cent royalty is charged on prospect work.

When ground is prospected by shafts the distance between the shafts varies, although the variation is not so great as when the prospecting is none by drill holes. The practice in Alaska varies according to the work, the resources of the owner, and the depth of the ground. Where the gold has not traveled far and in consequence the values are spotted, shafts should be sunk 30 to 50 feet apart, but such close work is never done. Twenty shafts to a 20-acre claim are common. Shallow ground, 6 to 18 feet deep, can be well and cheaply prospected in the winter months. Deep ground, as in the Fairbanks field, is expensive to prospect, and the prospect shafts do not average four to a claim. The cost of sinking shafts in the various camps is given below.

Twenty shafts, by 6 feet and 12 feet in depth, timbered in thawed ground, or untimbered in frozen ground, cost from $1,200 to $2,000. If steam thawing is employed, the outfit, consisting of a 6-horsepower boiler, three or four steam points, steam hose, and pipe connections, will cost from $300 to $500. Hot stones, hot water, and wood fires are more generally employed in prospecting ground in the remote camps. The hardest ground to prospect is that which is partly frozen. For example, in the Birch Creek and Fortymile districts shafts 15 to 25 feet in depth penetrate frozen ground and require no timbering until they are within 5 feet of bed rock, when a rush of water is frequently encountered. The entire labor of sinking the shaft through the overlying barren material may be lost, as the shaft may be flooded before pay gravel is reached.

U. S. Geological Survey

BULLETIN NO. 263 PL. Ill

.1. Churn Drill Mounted On Scow, Snake River, Alaska.

#. Winter Dumps, Klondike.

purington] PROSPECTING. 41

Cost Of Prospecting In Different Localities.

In the Juneau district prospect shafts must be square set, and cost on an average $6 a foot, and in heavy landslide $20 a foot. In the Porcupine district the cost of a cut 25 by 12 feet and 40 feet deep is $50 per foot, and that of an 8- by 8-foot shaft is $20 per foot. In the Sunrise and Chisna districts ground is prospected by open cuts. A cut 50 feet in length is reported to cost $2,000.

At Atlin ground is prospected mostly by drifting. On McKee Creek tunnels, timbered and lagged, cost $3.50 per foot. On Spruce Creek the cost of posts and caps, 10 inches thick and 6 feet long, is 50 cents each; lagging, 10 cents each. On Gold Run thirty 6-inch holes are said to have been drilled to a depth of 32 feet by a churn drill (cost, $3,500, laid down),. at the rate of $1 a foot.

In the Klondike drifts to prospect the bench gravels cost $7 to $8 a foot, timbered, and shafts from $5 to $10 a foot. In timbering, three sets of posts, sill, cap, and lagging are put in for $6, and as one-half cord of wood is used to a set the whole cost is $7 per set. In frozen creek ground two men, working three shifts, sunk a pit 5 feet square, 28 feet deep, using about 2-horsepower steam during thirty hours.

On Fortymile Creek, thawing ten hours, two men take out on an average 4 feet a day, the shaft being 5 feet by Si feet in dimensions. On American Creek prospecting is very difficult, as running water is always encountered at bed rock, even in the coldest weather.

In the Fortymile district shafts averaging 3i by 6 feet, untimbered, ost from $3 to $5 per foot. Seven shafts! by 8 feet and 23 feet deep iost $2,000. A shaft 7 by 3£ feet and 20 feet deep cost $5 per foot, ;he thawing being effected by means of wood fires and steam.

In the Birch Creek district shafts thawed down by wood fires to a depth not exceeding 20 feet cost $5 per foot. On Mastodon Creek, in his district, 11 pits 3 by 6 feet and 20 feet deep cost $650. Twenty pits 3 by 6 by 13 feet cost $7 per foot. The differences in cost here ire due to the varying amount of permanent frost in the ground, prosacting always being cheapest in solidly frozen ground. On Mammoth reek 100 pits 10 feet deep cost $5 per foot. Wood fires were used,

I feet being sunk each day. No timbering was required, and labor pas paid $10 a day.

In the Fairbanks district the prospect shafts cost from $7 to $10 per loot. Timbering is generally necessary, but very light poles are used ||ther as lagging or cribbing. The best S3stem is to put in 6-foot .sets f 3-inch poles, and outside of these to lag with 2-inch poles vertically, lling in solidly between the poles and the muck or gravel with moss. hafts cribbed with poles horizontally are more likely to get out of umb. Four shafts sunk on lower Fairbanks Creek cost $5 per foot, Hid were 32, 44, 53, and 54 feet deep. On Cleary Creek a shaft 4 by

I I feet and 75 feet deep (hillside claim), cribbed with 3-inch poles, cost

42 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263

Wood fires were used in thawing. On Pedro Creek 19 pit* 3£ by 7 by 12 feet cost $1,140, and on an adjoining claim pits 3 by ( feet and 18 feet deep cost $6 per foot. The light timbering and mosf filling used in the Fairbanks mines is to prevent the muck walls f ron thawing and caving.

In the Rampart district 30 pits 3 by 6 feet and 20 feet deep cosi from $75 to $100 each. The ground was parti thawed, but requirec no timbering.

In the Nome district, on account of the entire lack of native timber shafts are cribbed with 1 or 2 inch planking, set close together, no sets being used. On the Snowflake bench claim, on Anvil Creek, the crib bingwas reenforcedby 2 by 4 inch posts in the corners. Five dollar] per foot is the average cost of 4 by 5 shafts, timbered, in unfrozen oi partially frozen ground.

On Bonanza Creek, near Nome, pits in the shallow creek bed, 3 by j feet and 7 feet deep, are said to cost 50 cents per f oot.a The ground is only lightly frozen and requires no timbering. On Ophir Creek, ir the Council district, it costs on an average $5 to sink pits 7 feet deep

In the northern part of Seward Peninsula the ground is solid} frozen. In the Kougarok district pits 35 feet in depth, with stean thawing, cost $8 per foot, and require no timbering.

In the Candle or Fairhaven district, adjacent to Kotzebue Sound, 2£ pits 12 to 15 feet deep cost $4 a foot. It was necessary to thaw tc bed rock. The equipment cost $500.

Results Of Prospecting.

Numerous reports from many parts of Alaska indicate that the amount of gold obtained per cubic yard from prospect shafts does no equal that extracted subsequent actual mining. The reverse is very rarely true. It is difficult to assign a reason for this discrepancy othe: than that, owing to the frozen condition of the gravel, some of th< gold escapes when small lots are washed in the winter. Frozen grave 1 does not easily disintegrate, even in hot water, and unless the residuin from panning or rocking is saved and re washed, losses very likelfl occur.

It is needless to urge the importance of prospecting ground in i thorough manner before expensive machinery is installed. The man; failures through the long history of mining which have resulted from precipitate expenditure to exploit supposed valuable properties presen an open page of admonition to him who cares to read.

The sampling of winter dumps as they are extracted does not appea to have received the attention which it deserves. A method used b; I Mr. Kelley, of Dominion Creek, in the Klondike, is as follows:

The ordinary conical dump of frozen gravel, PI. Ill, B (p. 10)

a This work is probably done in the winter with labor at $2.50 a day and board.

ptjrington.] WATER SUPPLY. 43

assumes a somewhat steeper angle than that of loose material. One measured in the Klondike had a slope of 40°. From experience it has been found that if the ground is of uniform richness, 80 per cent of the values are contained in the upper two-thirds of the dump, which has a content of approximately 8,000 cubic yards. The apex of the dumps is generally 30 to 40 feet above the base. Four times each day 5 pans are taken in sampling — one from each quadrant of the clump one-half way down from the top — and one pan from the apex. The results of the 20 pannings are put together before weighing, and 50 per cent of the result is taken for the average value of what has been taken out during the day.

Neglect to appty some form of sampling to the dumps has caused manv lamentable failures in the Klondike. Winter operators of the Fairbanks district should keep themselves assured by constant sampling that the gravel they are getting out at such a cost carries values.

Water Supply.

Climatic Conditions.

Land areas in high northern latitudes are characterized by distribution of their natural resources that is unfavorable to economic use. In Alaska the great forests that characterize the south coast are replaced by stunted growths of spruce in the gold fields of the interior and by willow copses in Seward Peninsula. During a normal year the rainfall at Juneau, as may be seen from table 2 (p. 48) compiled by Dr. Cleveland Abbe, jr., is over eight times as great as at Eagle, on Yukon River. The catchment area at Juneau is only 4 square miles, and, as the grades of the hillsides are precipitous, the rainfall quickly runs off. A small amount of the water is used for power in connection with milling operations and for mining placer gold. The lort, steep creeks and rivers of the south coast have small catchment Dasins, and even were there any use for the water for placer-mining purposes, there would be difficulty in impounding it after the melting )f the snows in June and July.

Large catchment basins exist in the interior of Alaska, but the water o fill them is unfortunately lacking. At Eagle, where the annual ainfall is 11.4 inches in a normal year, the drainage area of Mission reek and its tributaries which flow into the Yukon is nearly 200 square ailes. Of the amount of water caught in a given area, however, very ttle is available for mining purposes. As an illustration take the ase of American Creek, a tributary of Mission Creek. The only lacer mining on it is done at a point about 12 miles distant from its louth, atan elevation of 1,600 feet. As the use of water for hydraulic lining requires a head of 200 feet, and as the height of the divides hich surround American Creek does not exceed 3,000 feet, it is evient that the only catchment area available is that lying between 1,800

Gravel And Placer Mining In Alaska.

[Bull. 263.

and 3,000 feet, and between the mine and the head of the creek, or its short tributaries. Of a total catchment area of nearly 75 square miles for American Creek, only 15 square miles are available for the operations at the point referred to. If it were possible to catch all the water, say 11.4 inches in depth, which fell on this area during a season, and use it in hydraulic mining, it would amount to 1,500 miner's inches available for one hundred and twenty days, and would move gravel at the rate of 1 cubic to the inch of water. As in practice it is not possible to utilize at head over one-third of that theoretically available in the catchment area, the capacity of the water power available is reduced in proportion. (See tig. 1.)

Fig. 1. — Map showing American Creek drainage, Eagle district.

In certain parts of the Fortymile region it is not impossible that water conduits from 10 to 15 miles in length can be constructed to* bring water to the placer diggings. The Glacier Mountains, lying, west of the upper portion of Mission Creek, rise to heights of 6,000' feet, or 3,000 feet higher than the general level of the interior country, and should afford a more promising water supply than any other area adjacent to the interior placer mining districts. The great drainage system of the South Fork of Fortymile Creek may also be available to a less extent for obtaining water under pressure. Miners should

Urington.

Climatic Conditions.

jear in mind, however, that even if the water is at hand and the gravel deposit extensive, the attempt to work by the hydraulic method where i grade of 6 inches to 12 feet can not be obtained will probably fail. In the Fairbanks and Birch Creek districts the rainfall may be assumed to be no greater than that at Eagle. The catchment area that ies at an elevation sufficient to supply the placer ground with water it a proper head for hydraulic operations is insignificant. Even were jhe auriferous gravels in that district so situated as to be hydraulicked, water for that purpose could not be obtained. The small amount of water which runs in the creek bottoms is available at heads not ex- 3eeding 25 feet, by means of ditches, for sluicing purposes. It is of variable quantity, however, and must be husbanded with the greatest jare. The promiscuous cutting of timber and stripping of moss, which are the inevitable accompaniments of the exploitation of the

liberie-,

Scale

smiles

Fig. 2.— Map of part of Birch Creek district.

Dlacers, will tend to gradually diminish the supply of water. (See figs. 2 i,nd 3.)

Of the interior districts the Rampart and Fortymile appear to be post copiously supplied with water, and these are the only districts n the hitherto developed interior where considerable bench deposits iave been found. It seems not improbable that a survey with reference to locating the larger catchment areas at sufficient elevation may esult in obtaining water for hydraulicking the bench gravels.

No data are at hand with reference to the rainfall in Seward Peninula. It may be assumed to be larger than that of the interior, and s probably fairly represented by the figure given for St. Michael, 8.1 inches, which fell during the summer of 1904. This amount, owever, was much less than that of the year before, and the gold roduct of the peninsula was thereby materially reduced. The facilies for making use of the water for mining purposes are better on

Gravel And Places Mining Aska.

[Buu . 263.

Seward Peninsula than in theinterior. Theavailable catchment areas on the peninsula are larger, and the construction of water conduits, owing to peculiar conditions which will be described, can be under* taken more cheaply. The Kigluaik Mountains and the Bendelebeu Range, lying roughly parallel to, and at a distance of 25 miles north ot the important gold fields of the South Coast, rise to heights ranging from 2,000 to 4,000 feet, and afford, as has been proved, a fairly continuous water supply during the open season. The York Mountains.

in the western portion of the peninsula, will doubtless furnish a sn ilar water supply should occasion require. Already the extensiv ditch system of Nome River. Ophir Creek, and Solomon River atfor an aggregate of 5,000 miner's inches of water in the drier portions o the open season. (See fig. 4. The expenditure for this work alread; made will probably not fall far short of a million dollars. Project' for the construction of water conduits are in contemplation whic compare favorably with, and even exceed in magnitude, those alread completed.

piRiN.noN] CLIMATIC CONDITIONS. 47

That the expense attendant on ditch construction in Seward Peninsula is justifiable in certain cases is not to be denied. That the most profitable method of converting the water into power has always been applied is, however, decidedly open to question. The subject will be further discussed under the head of ;i Hydraulic mining."

The average annual rainfall in California at various points on the west slope of the Sierras is approximately as follows:

Inch.-.

Sacramento 19

A.ul >urn - - - 20

3olfax 54

Disco 60

Summit 48

jo 28 miles

Fig.

-Map of part of Seward Peninsula.

Toward the north the rainfall increases in amount, and toward the puth it decreases. Table 2, giving the rainfall in Alaska, shows that there is a difference

rainfall between the coast and the interior gold districts that is too riking to need comment. Comparison of the interior rainfall may

made with that at St. Michael's station, which is the nearest point mailable representing Seward Peninsula conditions, yet the annual

Iiount of rainfall at St. Michael is still very small compared with at in California.

Gravel And Placer Mining In Alaska.

[Bull. 26?

The accompanying tables, compiled by Cleveland Abbe, jr., on th dates of opening and closing of interior water navigation and of tern perature, are here inserted because they have a direct 'bearing oi mining operations. In general, though the fact is contrary to popu lar opinion, it can be stated that climatic conditions, so far as tern perature is concerned, form the least of the hardships with which th miner has to contend. It is safe to say that no more generally health; climate can be found in any portion of the known world. Data i regard to the length of season available for use of running water wi] be found in the tabulated list of water conduits. (See table 8, p. 104.

Table 2. — Rainfall in Alaska.

[Compiled by Cleveland Abbe, jr.]

Rainfall In Inches.

Station.

Jan.

Feb.

Mar.

Apr.

May.

June.

July.

Aug.

Sept.

Oct.

Nov.

Dec.

Year.

Lengt recorc

Juneau

Skagway

Fort Liscum

Kenai

St. Michael

Camp Davidson. . . Eagle

[13.4]

Yr. m

Camp Colonna

Fort Adams

Fort Gibbon

>.2

Dawson, Y. T.

aAuthority: Inspector of Fisheries, Yukon Territory. NUMBER OF RAINY DAYS.

Station.

Jan.

Feb.

Mar.

Apr.

May.

June.

July.

Aug.

Sept.

Oct.

Nov.

Dec.

Yea:

Juneau

20]

[151. 9'

Fort Liscum

Kenai

St. Michael

Camp Davidson . .

Eagle

Circle

Camp Colonna . . .

7!

Fort Adams

Mil

Fort Gibbon

>io

Nulato

Anvik

Copper Center

Numbers in [ ] s Numbers preced

ire tot ed by

lis ma

de up knowr

from i l to be

nonth toosu

sin di lall.

fferent

year

l'l R.INGTON.]

Climatic Conditions.

Table 3. — Average dates of last spring and first fall frosts. [Computed by Cleveland Abbe, jr. Dates marked (?) arc from a single observation.]

Juneau

Ikagway

Fort Liscum

Kenai

St. Michael

Point Hope

Camp Colonna . . Camp Davidson.

Eagle

Circle

Fort Yukon

Place.

Last killing frost.

(?) Apr. 10 (?)

(?)

(?) June 1 (?)

(?)

(?) Junel5(?) May 10 (?)

(?)

Last spring frost.

Apr. 15 (?) June 1 (?)

(?)

Apr. 30 (?)

(?) (?) (?) (?)

First fall frost.

Sept. 20 Aug. 30

(?) Aug. 15 Sept. 15 Sept. 13 (?)

(?)

Sept. 1 (?) Aug. 20 (?) Sept. 30 (?)

First killing frost.

Sept. Sept. Sept. Aug. Sept. Oct. Oct. Aug. Sept. Nov. Oct.

30 (?)

15 (?)

Table 4. — Average dates of opening and closing of Yukon and Kenai rivers. [Dates marked (?) are from a single observation.]

Place.

Yukon River:

Fort Reliance .

Eagle

Circle

Fort Yukon . . .

Fort Gibbon...

Tanana

Nulato

Anvik

Kenai River:

Kenai

Ice breaks.

May

(?)

May

Mar. 18 (?)

River clear.

(?) May 15

(?) May 20

(?) May 22

Mar. 29 (?)

Ice running.

Oct. 20

Oct. 5

(?)

Oct. 3 Oct. 25 (?)

Oct. 15

(?)

Oct. 25

Dec. 5 (?)

River closed.

Nov. 5

Nov. 10

(?)

Oct. 26

Nov. 6 (?)

Oct. 20

Oct. 31

Dec. 15 (?)

Table 5. — Table of temperatures, Fahrenheit.

1 Station.

Jan.

Feb.

Mar.

Apr.

May.

June.

July.

Aug.

Sept.

Oct.

Nov.

Dec.

Length record.

Juneau

L7alden

Yrs. Mos. 5 a 18 0 10

pt. Michael

Sagle

11 -(12 1 0

i a Nonconsecutive months.

Stream Volumes.

i THE MINER'S INCH.

Before discus

p consider the

ceived so man

Bull. 263—0,

sing unit y va

the matter of stream volumes it will be necessary ; of measurement, the ''miner's inch," which has rying definitions in different mining districts.

50 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

On this subject0 Mr. Hamilton Smith makes the following statements:

Soon after the discovery of gold in California in 1848 associations or incorporated companies were formed for the purpose of building ditches and storage reservoirs for the supply of water to the placer mines. The amount of capital invested in these hydraulic works aggregated many millions of dollars, and a single company often sold water to hundreds of mining claims. The cost of water was by far the most important item in the miner's bill of costs, and hence it became necessary to have a standard measure, not only accurate but also so simple that the amount of discharge could be readily computed by the common miner.

This was accomplished by the discharge of the stream of water sold to each customer through a rectangular, square-edged, vertical orifice, with free discharge into the air and having a constant head. In different parts of the State the standard opening varied, the width varying from 2 to 4 inches and the head above the top of the opening from 4 to 7 inches. Each square inch of the opening was called "a miner's inch;" hence in a locality where the standard opening was 2 inches wide, if the miner wished a flow of 50 miner's inches, the orifice was 25 inches long, and if only 10 inches was needed the length was reduced to 5 inches.

This method is analogous to the pouce d'eau used in southern France, and was probably first introduced or suggested in California by some French or Mexican miner; the simplicity of this mode of measurement, combined with a sufficient degree of accuracy, soon brought it into general use on the Pacific coast wherever water was sold for mining, irrigation, etc.

The standard which had been in use since 1852 or 1853 in the mining districts supplied by the Eureka-Lake, Bloomfield, and Milton water companies in Nevada County, Cal., was an opening 50 inches long, 2 inches wide, with constant head above opening of 6 inches; the flow from this was called 100 miner's inches. Generally the miners bought water for ten hours per diem at an agreed price per inch; for example, a miner using 350 miner's inches, for ten hours each day, at the rate of 15 cents per inch, paid the water company $52.50 per diem, and received the amount of water which would flow through an orifice having an aggregate length of 175 inches, a width of 2 inches, with a head of 6 inches above the top of the opening, during a period of ten hours.

When water was used for the whole twenty-four hours of the day the flow was termed "a miner's 24-hour inch," and, of course, meant 2.4 times the amount of discharge of "a miner's 10-hour inch."

In California, as larger amounts of water eame into use, wider openings were adopted, one being 12 inches high, 12f inches long, with a constant head of 6 inches above the top of the opening.

Experiments made in California by A. J. Bowie, esq.,6 to determine the value of the miner's inch, defined as the one two-hundredth part j of the quantity of water which would flow through the last-named aperture in a l-inch board under head of 6 inches above the top of the discharge, showed that 1 miner's inch discharged in —

Cubic feet.

1 second 0. 02499

1 minute 1. 4994

1 hour 89. 9640

24 hours ; 2, 159. 1460

" Hydraulics, 1886, p. 277.

Bowie, A. J ., jr., A Practical Treatise on Hydraulic Mining, 1885, p. 126

rington.] STREAM VOLUMES. 51

Experiments on a single aperture of this form, used in determining Le North Bloomlield standard made by Hamilton Smith, jr.,a gave a scharge (a mean of two different openings) of 302.7 cubic feet per inute, or 2,179.4 cubic feet per miner's inch in twent}-four hours. The miner's inch used in this report is one two-hundredth part of te amount of water which will flow through an opening 12 inches gh by 12f inches wide in a l-inch plank, under a constant head of inches above the top of the discharge. This may be taken for 1 practical purposes as equivalent to 1.5 cubic feet of water per in iitc, or, in other words, 1 cubic foot per second equals 40 miner's ches.

A simple means of ascertaining the approximate number of miner's ches in an open conduit is to select a straight portion of the ditch or ime where the water runs quietly and where no accelerated velocity is been imparted to it. One hundred and ten feet measured along le bank should be called 100 feet. Floats made by weighting empty irtridge shells with shot or small stones and fitting into them cylindrical wooden plugs 4 or 6 inches long are then placed in the canal as lietly as possible. Note the average time which it takes several of iem to traverse the distance, divide the distance in feet by the averse time in minutes, and the result will be the velocity in feet per inute; this multiplied by the area in square feet will give the num- E of cubic feet of water flowing per minute. To get the number of iner's inches, multiply the cubic feet per minute by 2 and divide P3.

California, Colorado, and Montana have, by State law, made the ifinitions shown below:

Value of second-foot ( cubic foot per second) in miner's inches.

Miner's inches.

lifornia 40. 0

|lorado 38. 4

ntana 40. 0

([The measure is of great value and should be defined by Federal law, slice at present it is used in an indefinite sense. The placer miner gnerally assumes, when he is buying water, that he is getting 1.5 ethic feet per minute for each inch, or the inch measured under 6-inch bad above the top of the discharge, whereas, in reality, the inch sold hn is equal only to 1.2 cubic feet per minute, being measured under l|ead of 4 inches above the center of an orifice 2 inches wide/

Tydraulics, p. 282.

[over, A. P., California Journal of Technology, quoted in Eng. and Min. Jour., May 26, 1904.

The legal definition of the miner's inch in use in the Yukon Territory, as given to the writer by MA. J. Beaudette, the Government mining engineer, is one-twelfth the amount of water that will lirough an orifice 2 inches high by 6 inches wide under a constant head of inches above the ceer of the orifice.

Gravel And Placer Mining In Alaska.

[Bull. 263.

Table Of Stream Volumes.

Table 6, below, showing stream volumes in miner's inches, represents an attempt to combine at least approximate data relating to the amount of water which flows in northern auriferous streams during the open season. The few gagings that were made during the course of the trip were by Price current meter. It was found that variations from day to day in all parts of the country were exceedingly frequent, the volume on one day being sometimes from one-third to one-half that of the succeeding da}r after rain. Where a range between two amounts is given, the smaller figure may be taken as representing the most frequent condition.

Table 6. — Approximate stream volumes, in miner's inches.

District and stream.

Gagings.

Volumes in miner's inches.

Time.

Authority.

Remarks. 1

Juneau district:

Gold Creek

500-20, 000

4, 000-8, 000

1,000

500-2, 000

1,000

500-15, 000

55, 000-300, 000

68-17, 641

Open season.

This report

...do .

Low to flood.

Above mean. Low.

Mean. Do. Below mean.

Below forks.

Atlin district:

do

...do

do

Klondike district:

Klondike River

do

Canadian government engineer.

do

July

do...

Gold Run

Canadian government engineer.

Eagle district:

Discovery Fork

Circle district:

do

70, 000

do

July

do

Junction of Eagle Creek and Mastodon Fork.

Rampart district:

Minook Creek

July '

1, 000-10, 000

50-1, 000 600-4, 000 500-3, 000 200-2, 000 200-2, 000 100-1, 000 200-1.000

Open season.

do

Members of Geological Survey.

do

Ruby Creek

do

Slate Creek

do

...do

Pioneer Creek

do

Purixgton.]

Stream Volumes.

Table 6. — Approximate stream volumes, in miner's incites — Continued.

District and stream.

Gagings.

Volumes in miner's inches.

Time.

Authority .

Remarks.

Rampart district — Cont'd. Glen Gulch

Open sea son.

do

Members of Geological Sun ey. do

do

do ...

do

...do

do .

do

Fairbanks district:

August ... do

do

Wolf Creek...

do

do ...

do

Creek.

Nome district:

300-1,000

12, 000-20, 000

8, 000-18, 000

500-2, 000

100-1, 000

250-2, 000

3, 000-20, 000

200-1,000

800-4, 000

6, 000-50, 000

500-2,000

1,000-5,000

Open season .

do

Members of Geological Survey.

do

Gilmore and Pedro.

do

do ...

do

...do .

do

Council district:

do

...do

do

feolomon district:

do

Grades Of Streams.

No subjects are of greater importance for the consideration of the )lacer miner than the grade available for moving his gravel and the rertical space which he can obtain for a tailings dump. Neglect to carefully consider the natural grade of the ground on which the pro-

f)sed operation is to be undertaken will generally result in financial lure. Alaska is not characterized by steep grades in the parts which are ich in alluvial gold. In fact, with the exception of the relatively mall placer districts of the South Coast province, the long-continued

54 GEAVEL AND PLACER MINING IN ALASKA. [bull. 26

conditions of erosion have produced surprisingly low gradients in tt streams. Table 7, below, gives the grades of streams in the gol< producing districts of the north. For the sake of showing the defee of Alaska in the important requirements of grade, the lowest figure ] the table gives what is frequently referred to by gravel miners i " sluice-box grade." If the sluice boxes are carried on a grade lowc than 6 inches to the 12-foot box, the gravel can not be economical] moved through it except by employing an excessive quantity of wate By comparing the sluice-box grade with those of the various Alasfe creeks, it becomes evident that in nearly every case the material, eittl before entering or after leaving the tail sluice, must be artificial] elevated in order that the sluice may have sufficient grade. Tl various devices in use for accomplishing this elevation will be di cussed under proper headings.

Table 7. — Stream grades along important sections of their courses.

Average fall Juneau district: in feet per mi

Gold Creek 2!

Nizina district:

Dan Creek 2(

Atlin district:

Pine Creek

McKee Creek 41

Klondike district:

Eldorado Creek i

Bonanza Creek

Gold Run J

Fortymile District:

Wade Creek '

Chicken Creek

Walker Fork f

Eagle district:

American Creek

Circle district:

Deadwood- Creek

Mastodon Creek

Mammoth Creek

Eagle Creek 1

Fairbanks district:

Fairbanks Creek

Chatham Creek 2 ''

Cleary Creek

Pedro Creek 'j

Rampart district:

Little Minook Creek

Hunter Creek

Nome district:

Anvil Creek j '

Glacier Creek 'j

Purington.]

Open-Cut Mining.

. Average fall

Council district: In feet per mile.

Ophir Creek 25

Melsing Creek 50

Solomon district:

Solomon River 20

Shovel Creek 90

Average sluice-box grade 220 ( or 6 inches to 1 2 feet) .

Open-Cut Mining.

Introduction.

Under this heading will be discussed the various methods of mining by which gravel is taken out of open cuts — either simple pick-andshovel methods or methods involving the use of mechanical contrivances. Hydraulic methods will be considered in a later section. The simplest of the open-cut methods dominated throughout the province up to within a few years, to the practical exclusion of all others except winter drifting, which will be considered below. To-day probably 60 per cent of the placer-mining operations in Alaska are confined to

Fig. 5.— Klondike rocker.

open-cut methods, and this investigation has brought the proof that, when combined with proper mechanical devices, these form often the most economical mode of exploitation.

Open-cut methods can be conveniently grouped under various headings, but the underlying principle of excavating and transporting the material to the washing apparatus, either by hand labor or by some mechanical means, remains the same. It therein differs from hydraulic mining, where the gravel is moved by water under pressure. There are, of course, various intermediate processes, which will not require separate consideration.

Rocker And Long Tom.

The simplest method of work which the miner adopts after he has passed the stage of panning is that of shoveling from the bank and washing the gravel in a rocker. The use of the rocker is too well known to need description. The form employed in the Klondike, where its use has been nearly discontinued in mining, is shown in

56 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

fig. 5. Two men are necessary to use the rocker properly, while only 3 to 5 cubic yards of gravel can be washed in ten hours.

At no place was the long torn seen in use in the north, although it was formerly employed to some extent in washing the Nome beach placers.

Shoveling Into Sluice Boxes. Conditions For Shoveling.

Conditions throughout many of the northern placer districts favor this well-known, simple, and cheaply installed method of placer mining, for in many localities the pay streaks are thin, ranging from 2 to 4 feet in thickness, rarely exceeding 5 feet. It is often applicable where conditions of transportation prohibit the installation of more elaborate plants.

When the total depth to the bottom of the pay streak does not exceed 12 feet, the overlying barren material can generally be " ground sluiced" oil', even where the grade does not exceed 1 per cent, at an expense varying from 7 to 20 cents per cubic }rard. The frozen muck which composes this overburden is from 50 to 75 per cent water, and the solid residue of silt or fine clay is easily carried away at any time of slight rise in the stream. The method of groundsluicing the muck is described under the heading "Hydraulic mining," on page 141. PL IV, A, shows the ordinary method of setting up a string of sluice boxes on a creek placer. This method is used in an elaborate form on Anvil Creek, where 5 strings of boxes and 120 shovelers give a twenty-hour capacity of 1,080 cubic yards.

The handling of the water is important. Even when the gravel has been solidly frozen .previous to stripping and sun thawing, there are generally from 15 to 25 miners' inches of seepage water, which work into the pit floor. This must be disposed of either by draining or by pumping. If sufficient water (50 miners' inches) is available, a ' c China pump" can be rigged up, as shown in PI. IV, B. This device is not economical in its use of water, for the water is generally of more value for other purposes in Alaska mining.

Dams.

As in all other forms of creek mining, great care must be taken to keep the creek water out of the working pits Iry means of dams. Dams constructed of sod walls lined with sacks have been found cheaper in the Klondike than those built of sod and brush. Pile driving is not advisable in the north, but in case timber is abundant cribbing is desirable, as illustrated in PI. V, B, showing a dam built across Discovery Fork of American Creek to impound water for " booming." The ends of the logs were set in frozen ground on both sides and the muck was allowed to ref reeze around them. The dam, 40 feet long, consists of 12-inch timbers, from 9 to 18 feet long, laid up in two rows, 5 feet apart, earth and rock filled, and braced with

U. S. Geological Survey

Ulletin No. 263 Pl.

A. Set-Up Of Boxes For Shoveli Ng-I N, American Creek

China Pump, Klondike.

purington.] OPEN-CUT MINING. 59

The duty of a man shoveling is variously estimated in different districts of the North. This form of mining- having been nearly discontinued in the Klondike region, very little information concerning it was obtainable. The extensive shoveling operations on upper Bonanza Creek were not visited. In one case, where a platform was used, 2 men shoveling, in two stages, a total of 9 feet lift, 2 feet of pay were shovTeled into the boxes at the rate of cubic yards per ten-hour man.

In the Birch Creek district the duty of a man shoveling from an average of 12 operations is 5 cubic yards in ten hours, the depth of pay averaging 4.41 feet, and the lift never exceeding 0 feet.

In American Creek, where the bowlders were large and men had to stop work to get them out of the way, the duty was 2-f cubic yards. On Discovery Fork of this creek the duty was 4 cubic yards, the depth being 5 feet.

In the Fairbanks district, where shoveling-in operations are few, owing to the depth of ground, the average of three seen was 7% cubic yards dut}, the depth shoveled being 3 feet of pay, part gravel and part bed rock. In no case was there a lift of over 5 feet.

In the Nome region 5.76 cubic yards duty is probably very near the average on a bank from 5 to 7 feet in height. In the case of the large operations of the Pioneer Mining Company, on Anvil Creek, the work has been so systematized that on the 3-foot bank handled the duty is 9 cubic yards per ten-hour man.

One operation on Solomon River, where the lift was high, and the bed rock irregular, 3.75 cubic yards was the on a 3- foot bank.

In the Council district of Seward Peninsula, including operations on Ophir, Crooked, Warm, Gold Bottom, Camp, and Penelope creeks, the duty of a man averages 6.63 cubic yards on an average height of bank of 3.5 feet. This average is affected by one case where on a limestone bed rock, with double lift, the duty was 3.5 yards; also by another where with eight-hour shifts, working on 3-foot bank with 5-foot lift, the extraordinary duty of 12 cubic yards per man was vouched for.

The method of working shallow placers by shoveling into boxes has much to commend it, especially when the water is drained from the cut, either with or without a covered drain. In Alaskan gravels exceeding $3 in gold tenor to the cubic yard of material handled by shoveling, frequently from one-half to two-thirds of the gold lies in the crevices of the upper 18 inches or 2 feet of the bed rock. Men directly shoveling this material can thoroughly clean the bed rock by the shoveling-in method. On the other hand, if horse scrapers, steam scrapers, or steam shovels are used, the bed rock is frequently not cleaned, and a gang of men must go over the ground a second time to pick up the auriferous material which has been left. This point is

60 GEAVEL AND PLACER MINING IN ALASKA. [bull.263.

of the first importance. No operator should contemplate the installation of mechanical excavators for working gravel without taking full account of it.

In considering methods of mining by water or mechanical power, the cleaning of bed rock by men may be permissible from an economic standpoint in exceptional instances, as, for example, where a thick overburden is cheaply removed by hydraulicking and a very thin rich pay streak remains. When, however, a mechanical method of removing overburden and low-grade gravels costs from 50 cents to $1 & yard, and the whole area has to be gone over again by men to wheel the rich pay to the sluice, the gravel must be extraordinarily rich to* pay a profit. The lowest cost of handling gravel by the method of shoveling in was found to be $1 per cubic yard on one of the creeks of Seward Peninsula, while the cost may reach $5 on some of the isolated interior creeks of Alaska. a From 10 cents to $1 per square yard of area worked must be generally added to the shoveling cost to cover the cost of stripping muck or overburden. Ground which exceeds 12 feet in depth of combined stripping and pay will rarely pay if handled by the method of shoveling into the sluice.

Horse Scraping Into Sluice Boxes.

Ground which can be worked by men shoveling into sluices can, under certain conditions, be worked satisfactorily by horse scraping, and at an expense of one-third of that necessary to shovel in. The most important governing condition is the degree of looseness in the gravel and in the underlying auriferous bed rock. Two horses, or, better, mules, hauling a scraper, with driver, will cost from $17 to $23 a day, and in the ordinary small gravel of the Alaska placers, with soft schist bed rock, the team will scrape into the boxes from 30 to 40 cubic yards of gravel a day over a distance of 75 feet. On Penelope Creek, in Seward Peninsula, it was said that the team would handle as much as 10 men could shovel, the cost per cubic yard being 30 cents.

One common breaking plow with a team of horses suffices to break up enough ground for four scrapers. The method requires an inclined platform built up to a height of 10 to 15 feet above the bed rock, over* the head box of the sluice. A rectangular opening in this platform serves as a chute to the dump box. Generally the horses travel in an elliptical track, passing the end of the tail box and scraping the tailings from it, then entering the pit, scraping up the pay, and afterwards delivering it to the sluice. In Seward Peninsula the cost of this method can be brought as low as 25 cents per cubic yard, and in no part of the interior will it exceed 50 cents, exclusive of top stripping.

a See cost sheet, table No. 1.

Urington.]

Open-Cut Mining.

% cable

Many deposits were seen now worked by shoveling into sluices vhere at least an experimental trial of this method is to be recomnended. One of the strongest points in its favor is the cheapness of nstallation and the mobility of the apparatus used.

Steam Scrapers.

In view of the economical showing which the steam scraper has made

n handling tailings from the creek-mining operations of the Klondike

t is remarkable that so few at-

;empty have been made with it

:o scrape the alluvium from its

>riginal position. The ordinary

scrapers used in steam-scraping

operations on tailings in the

Klondike have a capacity of from

>ne-third to one-half cubic yard,

>perated by double drum, 2-cylin-

ler hoist; 16-inch drums, 25 to

horsepower capacity, handling

an average 250 cubic yards

loose material in twenty-four

tours, at an average expense of

:9 cents per cubic yard. The

manipulations of the scraper, con-

idered as a unit of the plant, take

I to 4 men on shift — a fireman, a

[joistman, and either 1 or 2 men to

ill, guide, and dump the scrap-

jr. The form and rigging up of

jpe scraper, with the system of heaves, pulling, and drawback xibles, is shown in figs. 6 and 7.

I(i the practice seen the scrapers rag the material from the pit to

lie dump, a distance measured prizontally from 100 to 300 feet

ijid vertically from 20 to 50 feet, pe scrapers are not always provided with teeth like the one shown i the figure, but this is advisable. A rigid bale should never be

as flat stones catch between it and the body of the scraper. 'he plants average $3,500 in cost.

,The rig shown in PI. VI, A (p. 62), is situated on Walker Fork, Forty - ijile district, Alaska, where a body of gravel 60 feet in width and 5 let in depth, with little or no stripping, was being mined. According to information obtained by Mr. L. M. Prindle the gravel was only

Fig. 6. — Small steam scraper, Klondike.

Gkavel And Placek Mining In Alaska.

[Bull. 263.

partially free, and little or no stripping was required. As a rule the scraper was found to clean the schist bed rock satisfactorily. The scraper used had a capacity of one-fifth cubic yard, being an ordinary horse scraper rigged for steam with pulling and drawback cables. A 6-horsepower hoist operated the scraper, giving a capacity of 100 cubic yards in twenty-four hours. The 10-horsepower boiler also furnished steam to operate the bucket elevator which lifted the gravel to the sluice from the hopper, to which it was dumped by the scraper. A conservative estimate places the cost of handling gravel with rig, 3

Pole/

§"sheave with !2"conic9l plate beneath

'double drum

Position of scraper can be j v altered by lengthening or .shorten/ng line to anchor

Anchor

Fig. 7.— Set-up of scraper, Klondike.

men being employed and one-half cord of wood burned in ten hours, at 40 cents per cubic yard. The operations were meeting with financial success.

The plant contains the elements of a device which, it is not unlikely, may be applied to the working of the wide, shallow creek deposits of Seward Peninsula, or of such creeks of the interior as Mammoth, in the Birch Creek district, or lower Pedro, in the Fairbanks district. If circumstances warranted, the sheave anchor (a rock-filled crib) shown in PL VI, A, could be made more easily movable by mounting it on a truck running on track, it being made fast by cable and dead-

U. S. Geological Survey

3Ulletin No. 263 Pl. Vi

Steam Scraping On Walker Fork, Alaska.

B. Dumping To Sluices, Klondike.

ington.] OPEN-CUT MINING. 63

in when occasion might require. The bucket elevator employed is t recommended, as the use of such contrivances for handling gravel, less they are specially and expensively constructed — as on large Bges — is condemned by experience. In place of this, the scraper 3uld be dragged entirely to the point of final discharge to the sluice

an inclined platform. The operation will necessitate the building

a more elevated sluice or washing plant, surmounted by a hopper, i gravel being fed from this in order that the feed may be as nearly atinuous as possible. Assuming that the elevation of the head box

the sluice shown in the illustration is 12 feet above the surface of i ground, the scraper could be dragged to double this elevation at a it not exceeding 10 per cent above that necessary to haul it up to 1 12-foot elevation. One of the types of washing plants described pages 193 et seq. would be applicable with modifications to a steam aping plant.

[t may be well to consider here the reasons why, in wide, shallow >ek deposits, steam scraping appears to be preferable to other ichanical methods. In general, it may be said that this method is plicable to operations on schist bed rock, but is entirely impracti- )le on limestone or other hard bed rock. This is also true of the am-shovel and dredging methods. Grant that bed-rock conditions j suitable, and consider a solidly frozen deposit of characteristic all gravel with muck and moss overburden, 150 feet width of pay i 7 feet in total depth from grass roots to bottom of pay. After moss is plowed up, the 3 feet depth of muck can be ground sluiced

in the ordinary manner at an expense of, say, 15 cents per cubic rd. The ground sluicing should be done at the earliest possible >ment in the open season or, preferably, late in the fall. The erator now has to deal with a stripped block of frozen gravel and riferous bed rock 4 feet in depth, carrying pay, or the material rich it is desired to sluice. A vertical bank of this material can not

attacked by any mechanical appliance yet devised, but if left covered for six weeks it will thaw to bed rock. The operator, wever, wishes to take advantage of the continual thawing of the rface by the sun, and to do this he must attack not a vertical but horizontal surface. The rate of natural thawing varies from 6 ;hes to 1 foot a week. The scraper armed with teeth rigged so as make a series of transverse cuts, say for 300 feet lengthwise of the mnel, will attack the ground, scraping off the thawed material :ter than an}' other mechanical appliance.

fhe sluice boxes or washing plant built to a height of 25 feet above surface of the ground can now be approached by a broad incline

form, or, if desired, the scraper may dump to cars which convey material by gravity to an isolated and conveniently situated washplant. The system adopted will depend on the magnitude of the

64 GRAVEL AND PLACER MINING IN ALASKA. [bull.2(

operations. In only very exceptional cases should the expense handling, after the material is once dumped from the scraper, 1 allowed to exceed 5 cents to the cubic yard.

The plant above suggested implies the use of a scraper of lar capacity and should handle the gravel at a total cost, including depr ciation charge and added cost of stripping, not to exceed 40 cents cubic yard in Alaska, provided that 700 cubic }rards of gravel a ds are sent to the sluice. In order to accomplish this a scraper, prefer bly of the bottomless, self -dumping type, of 6 yards theoretical capa ity, should be used. It will be found that actually 3£ yards will 1 delivered each time by such a scraper. The operations will require 60-horsepower boiler and doable-drum hoist, and the services of sev( men on a shift. The total running expense of the plant should a exceed $150 a day of 24 hours.

The double-drum hoist operating the scraper will have a position c the side of the sluice opposite that of the cut, and can be mount< on skids so that it can be easily moved by means of a sheave and dea< man if necessary. The sheave through which the drawback cable rui may be anchored to a weighted car running on 200 feet of track la parallel with the cut on the side opposite that occupied by the slui< and hoist. If it is desired to keep the drawback cable out of the it may pass through two sheaves, one anchored to traveling anchor ai one to deadman, the cables thus forming a triangular arrangement two of whose angles will as the car is moved to cover varioi parts of the ground. The car may be moved as often as desired, ai thus one furrow after another may be made by the scraper over a ti angular area as the ground thaws. By means of a rearrangement the sheaves it is found that nearly all of the ground can be covere A plant erected for the Klamath River Gold Mining Company a is pr vided with two li-yard scrapers, which travel back and forth alte nately, both cables acting as pulley and drawback cables. Two sheav are used on the side of the excavation opposite to the washing plar " These sheaves are attached to a spreader which keeps them spaced given distance apart, and to each end of the spreader is attachec tackle which runs back at an angle to deadmen to which they a securely anchored."

The type of bottomless scraper shown in fig. 8 (p. 65) was seen successful operation stripping loam at a reservoir excavation ne Portland, Oreg. It has a theoretical capacity of 6 yards, and actua I handles a little over half this amount. Measurements of a spoil ba i showed that in seven ten-hour days, stripping to 4 feet in depth, 4 cubic yards per shift had been handled. The scraper was maki i furrows over 300 feet in length. A 60-horsepower boiler was us< (

a Yeatman, J. A., Automatic excavator for placer mining: Min. and Sci. Press, Dec 17, 1904.

U. S. Geological Survey

A. Derricking At Fairbanks, Dumping.

B. Derricking At Fairbanks. Loading.

Open-Cut Mining,

but only one cord of wood at $2 per cord was burned. The double irum hoist was provided with 10 by 12 inch cylinders and was geared to 1. Four men, a winchman, a fireman, and two scraper men were employed, at $2.50 a day. It was said that under these conditions the operations cost 5 cents per cubic yard. It was estimated that in a aaul of from 150 to 200 feet the scraper would deliver loam to the spoil heap at the rate of 2 cubic yards per minute.

The above suggestions regarding the use of self -dumping scrapers n northern placer mining will doubtless be looked on with considerable skepticism. No direct application of the method has, so fails known, been made in Alaska. The form of plant outlined is inexpensive as compared with many already installed in Alaska, having a capacity not exceeding 700 cubic yards. The sum of $10,000 should ample to install an entire scraper and washing plant in Seward Peninsula. Even should some form of steam scraping be found appli-

Bottomless steam scraper.

3able to the wider shallow deposits, the installation of elaborate cableways, traveling towers, and the like, is not advisable, as in most cases their cost would be prohibitory.

Self-Dumping Carriers.

The conditions in the Klondike district appear to have necessitated he adoption of this expensive method of placer mining. Outside the Klondike held the method was not seen except at one place on Mastolon Creek, in the Birch Creek district. The method is adopted to vork rich gravels where conditions do not permit working by ordinary hallow open-cut methods, and where drifting is impossible or nadvisable.

In considering the economic success of this method, a study of the ost sheet given in this report (table 1, p. 38), is most instructive. In he first place the average depth from eight Klondike operations con-

dered, namely 17.5 feet, is greater than that economically advisable Bull. 263—05 5

66 GRAVEL AND PLACER MINING IN ALASKA. [bull.2

(namely, 15 feet) for open-cut operations in general. The operate adopts this method because there are thawed streaks and channe in his deposit. If such ground is drifted, the chances are that he w increase his expense to a prohibitive amount through excessive tir bering and through pumping of seepage water, whereas by the ope cut method the water is handled by drain. The cost sheet shows th whereas $2.14 is the average cost of the above-mentioned 8 operatic in the Klondike, 7 drifting operations in similar deposits, with average depth of 25.3 feet, gave an average cost of $1.95 per cub yard, the depth of the pay or thickness of gravel actually sent to tl sluice being almost exactly the same in both cases, and the capacity the drifting being only 17.5 cubic yards less in twenty-four houi Granting, however, that in a given deposit carrying $3 to the cub yard of pay, the depth being 16 feet, drifting is impossible, and tl rich pay, 75 feet in width, must be worked by open cut. Whatev method be adopted the moss must first be plowed up and about 6 fe of muck ground sluiced off at a cost of 17 cents per cubic yard. Ne 6 feet of barren gravel or sand must be removed, either b}7 hor scrapers at 60 cents per cubic yard, or, if the plant warrants the opei tion, by steam scraper at 49 cents per cubic yard. The 4 feet of pj being laid bare, what method shall be adopted to get it into the sluice On account of the necessarily short life of the operations, a pla whose first cost exceeds $5,000 is out of the question. The greate expense will then result from the hand shoveling in the pit. The g( ting of the material into the receptacle in which it is conveyed to t sluice is the principal item of expense in the operation. It is thei fore necessary that the high-priced shovelers get as much gravel in the wheelbarrows or buckets as possible. The bucket, 37 inches squa on top, 35 inches square on bottom, and 25 inches deep, holding thirds of a cubic yard, is dropped into a crib built in the bottom the pit, to which the shovelers wheel their dirt in wheel barrow From 4 to 6 wheelbarrows are necessary to fill the bucket. The is no mobility to the bucket; it must always rise and fall to t same spot. Men instead of occupying all their time in shoveling m employed nearly half of it in wheeling and dumping. Five operatic are necessary to get the gravel from the bank to the sluice, name (1) shoveling into wheelbarrows, (2) wheeling to bucket, (3) dump to bucket, (4) raising bucket to carrier. a (5) conveying and dumping sluice. (See PL VI, B.)

This may now be compared with the derricking system. On Pec Creek, Fairbanks district, an open cut 15 feet of depth with 9 feet pay gravel is worked by derricking. The plant has a capacity of £ cubic yards a day, which is handled at a co*t of $1.75 per cubic yd The plant costs no more than the average price of a self-dump

The Dawson self-dumping carrier and its use is described under the heading " Drift raining," p

U. S. Geological Survey

Bulletin No. 263 Pl. Viii

' v1- "*rfBBi /iJJ

.1. Skids For Derricking.

Bf

Ii P

p

JUjl

i:

i

p

'

t apt '. eLBCV '

B. Derrick Bucket.

nmiNGTON.] OPEN-CUT MINING. 67

sarrier plant of daily capacity not exceeding 200 yards. The first cost bi all, including a 30-horsepower boiler, was said to be $4,500. Here jhe gravel is shoveled into buckets holding 8 cubic feet. These buckets are trammed on small trucks running on wooden tracks, hooked >nto by the derrick cable and lifted and conveyed at same time to lie sluice. The derrick boom has a radius of reach of 40 feet, and a nuch smaller proportion of time is consumed by the shovelers in jamming than when the fixed bucket on cable is used/' The expense vas increased in this plant by the necessity of continually thawing with 24 points. PI. VII, A and B (p. 64), shows the operation of the dericking plant.

As against the 5 operations of the cable tram system, there are mly 3 in the derricking system if properly handled. The proof hat the derricking system is superior to the wheeling and cable ram system is evident from the comparative cost. The services of a nan at the dump box are generally necessary in all cases under the present sluicing practice, so that the self-dumping arrangement of the mcket helps but little.

It should be noted that the Fairbanks operator was working under higher prices generally than the Klondike miners, both for labor (at >10 a day, as against $7.50 a day) and for general supplies, and he also lad an excessive amount of steam thawing. His lower cost depended u'imarily on his increased capacity, resulting for the most part from he increased of each shoveler, owing to the expeditious and daptable system of hoisting and conveying afforded by the derrick. derricking system in use on Seward Peninsula will be separately described.

The conclusion is that while the cable tram system, using the Dawon carrier, is excellent for drifting work, it is not to be recommended or open-cut work where it is possible to obtain space for installing a lerrick.

Derricking.

The plant described below is located on Ophir Creek, in the Council lining district of Seward Peninsula. The stream has been turned dde and work is proceeding in the old bed. The distinctive feature

the plant is the use of derricks in overcoming exceptional difficulties icountered in the character of the deposit. Hand labor is used in ccavation, while transport of material to be washed and disposal of

ilings are accomplished by derricks.

The pit in which work is being done depends for its shape and size aon the method of working and length of the derrick boom. An

ea of 30 feet beyond the end of the derrick boom is worked. A pit,

uglily circular, having a diameter of 140 feet, is the result, since the

a See also special description of derricking, pp. 67-71.

68 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

boom reaches approximately 40 feet in its sweep, and the buckets are hauled 30 feet from the bank. Under a stratum of sand and soil] varying" from 4 to 5 feet in thickness, the gravel, in places considerably mixed with sand and clay, descends to bed rock, usually 30 feet below the surface. The gravel is entirely unfrozen, rounded, and for the most part small, not over 10 per cent exceeding 6 inches in diameter, while no bowlders are found above 18 inches. Bed rock is a massive limestone, extremely irregular in its position, and causes the greatest difficult} in the extraction of much of the gold, though this same feature must have played an important part in the enrichment of the claim. (See PI. VIII, p. 66.) In places deep holes have been made by action oi water, and the depth to which work is carried in the recovery of the gold depends entirely upon the economy with which it is extracted. There is no doubt that much gold remains below, to obtain which would not be profitable under present conditions.

Excavation is accomplished entirely by pick, the gravel being shoveled into the derrick buckets. These buckets are hauled by the derrick line, guided by hand, upon wooden skids (see PI. VIII, A), to a point directly beneath the end of the boom, where they are hoisted and carried to the dump box.

The buckets are of 11 cubic feet capacity, and are so practical as to warrant detailed description. They are made of crude oil drums or gasoline tanks, cut to a height of 2 feet 8 inches, and are 2 feet 5 inches across the top. (See PI. VIII, B.) Two lugs to hold the bale are set opposite each other one-fourth distance up from the bottom. The bale is made from the original hoops of the drum. Th( bottom edge is strengthened by the original flange of the tank, whilt on the upper edge has been riveted the flange originally at the top o: the tank. The bale is supplied with a catch which, when the bucke is traveling, rests in a notch constructed on its edge, which holds thn bucket in an upright position. On reaching the dump box, a man on the platform with his shovel frees the catch, and the bucket dump| in turning bottom upward. (See PL IX, A.) In fitting the lugs hold j ing the bale, a piece of iron 9 inches square is riveted to the inside om1 the material composing the drum, which is one-eighth of an inch thiols To the outside of the drum a strip 9 inches long, 2i inches wide, am one-half inch thick is also riveted, and to this the lug (2 inches long) i i welded, making a very strong construction. These buckets weigh 14 pounds and, including labor, blacksmith fuel, and original price ( drum, cost about $25.

The skids upon which the buckets are hauled are ordinary smooth timbers, and are not fastened down. This admits of rapid change i accommodating the hauls to the advancing work. It is desirable i have these timbers as much as possible in a radius of the circ described by the derrick, as this gives a straight haul on the boom.

!

U. S. Geological Survey

Bulletin No. 263 Pl.

A. Dumping Bucke

B. Rough Bed Rock And Bowlders Piled In Pit.

jrington.] OPEN-CUT MINING. 69

The derrick in use at this plant is of a very simple and practical sign, there being but one haulage line, which with gravity utilized i the lean of the derrick accomplishes the desired work. The derrick sans toward the pit in which excavation is taking place — i. e., when t rest the boom swings away from the hoisting engine. (See PL L) The hauling line passes through a block at the foot of the mast ad a few feet in front of it, or toward the direction of haul. In this osition immediately upon receiving a hauling strain the boom tends ) move toward the dump box, and once there, having disposed of its >ad, returns by gravity to the pit. To the end of the boom is attached rope by which a man in the pit giving his entire attention to this peration can regulate the swing of the boom to a nicety. By snubing this line about a post set firmly in the ground, hauls can be made 1 any direction with no inconvenience from the swinging of the boom, rid the dumping of the load on the platform can be accurately ijusted. The derrick on an average lift raises material about 25 feet nd carries it approximately 85 feet to the sluices. The amount of laterial handled is generally 500 cubic yards in twenty -two hours, 'ower is obtained from a 15-horsepower boiler and 8-horsepower ouble engine hoist, which burns one-half cord of wood in twenty - mv hours at $15 a cord. The derricks are of Washington fir, both oom and mast being 40 feet long. The hauling line, one-half inch i diameter, is of crucible steel wire, plow-share steel not bending isily enough, and the guy lines, three-eighths inch in diameter, also f steel, are tightened by watch tackles.

Stones over 12 inches in diameter are not sent through the sluices, eing piled by hand in the center of the pit. Larger stones and owlders of bed rock are handled by the derrick and piled in the same tanner. (See PL IX, i>, p. 68.) The removal, however, of stones sceeding 2 tons in weight is not attempted with the derrick. A love is necessary each thirty days, and in advancing the entire plant pproximately 110 feet eighteen hours are generally consumed. An nxiliary flume and dump box must of necessity be used to permit ich rapid change.

The dump box, which is furnished with a platform sufficiently large prevent spilling of material, is from 6 to 12 feet above the ground, is 16 feet long and has a grade of 14 inches. Below it are 132 feet boxes, 20 inches deep and 16 inches wide, with a grade of 7 inches the box length (12 feet). These are furnished with pole riffles ade 2 inches square, capped with iron, and will last two seasons. t the end of the string is a very efficient undercurrent, invented on e ground. It consists of an ordinary sluice box furnished with iron dts approximately three-eighths or one-half of an inch in diameter, nning lengthwise with the box and placed side by side. Beneath ese bars, held by Hungarian riffles, is a quantity of quicksilver,

:i

70 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

which catches any gold that may have passed the preceding string. Such an arrangement, though of considerable use when gold is generally coarse, will not serve when fine gold is encountered. An undercurrent of greater surficial area and greater grade, carrying the water in a thin sheet, would then be demanded.

In washing the gravel 150 miner's inches are used. The water is brought from Ophir Creek in a ditch 1£ miles long. It is 6 feet onj the bottom, 9 feet on top, and has a grade of one-tenth inch to 100.1 feet. It cost $8,000.

Tailings are handled by a derrick and a self-dumping scraper. Power is supplied to the latter by hauling directly from the derrick boom, and its operation is directed by two men. In this case the derrick leans toward the dump pile, to which it carries its load by gravity, being hauled back by the steam winch. To the scraper is attached a rope which, on tightening as the derrick swings, dumps the load at itsj destination. . (See PI. X.) Both the derrick boom and mast are lOj feet long and are arranged like the excavation derrick, except that] the mast leans in the opposite direction. A 15-horsepower boiler and] 8-horsepower winch are used, and there are three men on each shift. The tailings derrick is not occupied more than one-fourth the working time of the pit derrick.

In all from 55 to 60 men are employed about the plant. A man is] continually needed at the mud box to trip the bucket and to feed tfl gravel as regularly as possible to the sluices from the platform. A winch man is needed at each derrick. A man in the pit devotes his entire attention to the snubbing line, while two men are necessary ori the scraper. The latter feature could possibly be improved by some mechanical method not requiring the hand labor. Wages are 50 cents an hour, with board, and work is continued eleven hours each shift.

Besides the derrick plant above described another, seen on Ophir Creek, made use of iron skips of li cubic; 3ard capacity, which werej run on trucks to the working face and, after loading, were trammed within reach of the derrick and lifted to the sluice. As nearly ascould be learned, while the capacity of this plant was from 15 to 20 per cent higher than the one previously described the work was not being done so cheaply. In the last case it was necessaiy to pump the seepage water from the pit, while in the first case all seepage water was naturally disposed of by draining into the peculiar cavernous limestone bed rock. In derricking plants in general, large rather than small buckets or skips are to be recommended, but the various elements of the plant should be so coordinated that the capacity of the derrick is not above that of the shoveling and tramming or of the sluice.

The derricking plant seen on Pedro Creek, in the Fairbanks district, has been described in connection with the method of using* the cable

U. S. Geological Survey

'/'c yards

bucket 25 feet

Efera t/on to s

Urington.]

Open-Cut Mining.

ram and self-dumping bucket in open-cut work. Its efficiency was found to be high and Us cost low in comparison with this well-known Klondike method. In general it nay be said that derricking is a simple, efficient, adaptable, and comparatively cheap method of forking open cuts whore gravel nust be shoveled into the first 'eceptacle by hand and the bed *ock cleaned b}r men.

Tracks And Inclines.

The track and incline working it No. 8, Anvil Creek, Nome district, is fairly representative of )pen-cut work by this system. See tig. 9.) A special feature of lie plant, however, is the removal )f the overburden, in all 7 feet )f muck and 5 feet of barren gravel, by hydraulicking. Seven mndred miner's inches are used hrough a giant, under a pressure )f 200 feet obtained by pumping. Aiter the barren ground has been removed the remaining gravel, iveraging about 6 feet in depth, s shoveled into cars, pushed to lie foot of an incline, elevated, ind washed. The tailings are mpounded on the claim, being

craped from the end of the

juices by 2-horse scrapers. At the time of observation 6

ars were in use, though this

umber can be varied to suit the

onditions in hand. Two men

re employed with each car.

'hey take turns in shoving the

ar to the incline, one remaining

t the bank with pick. The cars

t this plant were of a capacity

f 22£ cubic feet, though larger

nes might be found more eco-

omical. From 250 to 300 cars are run up each 10-hour shift. The material is lifted 30 feet to the mud box and there clumped by

72 GRAVEL AND PLACER MINING IN ALASKA. [bull. 26

hand. A man is continually employed for this duty. He also watch large bowlders and prevents jamming in the flume. However, ver few large stones are allowed to pass through, for in the work of exes vation the larger rocks are piled at one side of the track.

One man is employed at the hoisting winch and does his own firing Three 114-pound sacks of coal are consumed each shift. A 15-hors< power boiler is used with vertical engine, and a five-eighths inch cab] hauls the cars.

The dump box is 24 feet long, 4 feet wide, and 3 feet high, and hi a grade of 1 inch to 1 foot. Following this are 240 feet of boxes wit a grade of three-fourth inches to 1 foot. The boxes are 16 inch* wide and 14 inches high, and are supplied with cast-iron grate riffle These are 16 inches square and can be used either as Hungarian c longitudinal riffles. In washing, 125 miner's inches are used, a obtained by gravity from a claim above. After being used the wat€ is caught in a retaining dam, settled, and carried by flume to a low* claim, where it is sold. Two 2-horse scrapers are used to keep tai ings clear, and all gravel is impounded by a brush dam upon the clain

A little gold is caught in the entire string, though by far the great] proportion is retained in the mud box and that following. In tt mud box a perforated iron sheet laid over the riffles aids the movin of material and prevents clogging. In the center of this sheet : placed a heavy iron plate which receives the heavy fall from the cai and saves the bottom of the mud box.

Bed rock on this claim is mica-schist, though in places the pay underlain by a stiff clay. The gold sinks in the broken schist aboi 2 feet, but not at all in the clay.

A bed-rock drain, 250 feet long, has been cut nearly level, which joined by small drains from various parts of the pit. Only about 1 miner's inches of water were running from the drain at the time observation. Men are paid $5 a day, with board.

The advantages of the car-and-incline system are not especial pronounced. The method of stripping used in the above-describl plant, or at any plant where water under pressure is available ci hardly be improved upon. Where the overburden is thawed or whe: frost is encountered only in spots, as in the claim under discussion hydraulicking has been found the most economical and efficient mea: of removing material. The car system, however, has little of sol economic advantage to recommend it. In order to increase capaci more men must be employed to shovel. In this system an undi proportion of time is consumed in tramming the cars to the top of tl incline. A mechanical system, such as derricking or steam scraping ; has many advantages over the track-and-incline. In the Klondike, far as could be learned, the track-and-incline system does not make economical a showing as other methods of working open cut, althoug 1 the opportunity for comparison of efficiency was limited.

purington.] OPEN-CUT MINING. 73

The Steam Shovel.

Where the ground exceeds V2 feet in depth and is unfrozen, certain conditions justify the installation of a mechanical excavator of large capacity, say 1,000 cubic yards or more in twenty-four hours. It will seldom be found advisable to install so large and so cumbersome a machine as the steam shovel in the creek diggings of Alaska, for the ground is rarely deep enough to justify the expense of installation. On bench diggings, however, where the pit can be drained by gravity, the steam shovel has a value which has probably been underestimated. The fact that water under pressure is difficult or impossible to obtain for the hydraulicking of benches raises the question whether these bench gravels can not be excavated by other means. The value of the steam shovel lies in the fact that it performs for the earth worker that portion of his work which would otherwise be most expensive.

The ground which the shovel is to move must possess certain favorable conditions. In the first place, it must be entirely free from permanent % frost when the dipper lip of the excavator attacks it. If the ground holds a certain amount of permanent frost and this can be thawed by ground-sluicing the muck off at a period far enough ahead, the shovel may still have a profitable field, but its operations are likely to be more expensive. Heavy gravel and bowlders are easily handled by the mechanical excavator. It is safe to say that no quality or state of the Alaska gravels makes them unfit to be dug by the dipper except the frozen condition.

The bed rock must be of sufficient softness to allow the dipper lip to dig far enough into it to recover all the gold; otherwise a gang of men will have to follow the shovel to clean bed rock, and a large part of the value of the shovel will be lost. In one attempt to operate with a steam shovel in the interior of Alaska it was found that as many men had to be employed in cleaning the bed rock as in the entire remainder of the plant.

A prime essential to success, as has been proved by experience, is that the washing plant shall be isolated, the gravel being conveyed from the dipper to the sluice by some form of tramming. If cars are used, they should be large — 2 yards capacity, or even larger. Under ideal conditions the dipper will dump into cars which run by gravity to the hopper of the washing plant, the water being brought to the sluice also by gravity. The full cars would in this case carry the empties back to the pit. It is rarely possible, however, to find an auriferous gravel deposit in which such eminentl} fit conditions exist Ifor work. The tramming, even when it must be up an incline to a jheight of 35 feet above the pit floor, adds proportionately little to the expense, as will be seen by figures following. It is a common fault in iill steam-shovel operations that the shovel is ahead of the car discharge.

74 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

A partly idle steam shovel, however, is not so serious a fault as idle men, since the shovel draws no pay.

As to capacity, it is likely that a 2-yard shovel, fitted with extra long boom and li-yard dipper, will be found most economical. A 25- foot bank can be dug and caved. If the sluice and tramming capacity is 700 cubic yards a day, the shovel will easily supply the material if no frost is encountered.

PI. XI, A, shows one of the steam shovel plants in Alaska, operating on Anvil Creek. The work done by this shovel is considered satisfactory, though its installation is experimental, and a larger one is planned. It supplanted a hydraulic-elevator system which was condemned. The 25-ton shovel (three-fourths-yard dipper) is working on an 18-foot face. It has not reached the bottom of the gravel, and must make another cut 7 feet lower vertically before all the pay is extracted. It is said that from July 23 to September 1, 1904, 25,000 cars of li cubic yards capacity were dug and moved to the sluice boxes at a working cost of 12 cents a yard. The low bench is sufficiently above the level of the present creek to permit the pit to be

— "t — .,gmr — i Zliiux " — TnrijflljNsft Grade sluice 8 to/2 for Ist 30. remainder 7 rtn

.jgffSggQU"*1- MiiiiiiinnhYft ujpCOE First II boxes, iron riffles,— remainder 3j/' scraper

ajBBBBn'v/'--''%->C3Ct . $/ /5>Vaa, blank iron plates

W£$ 15 HR boiler

Fig. 10. — Plan of steam-shovel operations, Anvil Creek.

drained, the seepage water being handled by bed-rock drain. The workings were visited a. second time three weeks after the present cut was made. A complete section of the bank to bed rock is given below:

Feet. Muck 3

Fine gravel and sand 5

Fine subangular gravel 5

Large subangular schist and limestone fragments, stained with iron oxide, with a few bowlders up to 3 feet in diameter '. . 15

The upper 3 feet of muck was ground-sluiced; the remainder was moved by the steam shovel.

This frozen ground illustrates the peculiarly trying conditions with which the Alaska placer miner has frequently to deal. None of the ground encountered in 1904 was frozen. In the early part of the season of 1903, however, on account of the light snowfall during the preceding winter, the sides of a cut operated on were frozen to a depth of 8 feet and to a distance of 15 feet into the bank. This was annual

U. S. Geological Survey

Bulletin No. 263 Pl. Xi

A. Steam Shovel, Anvil Creek.

B. Steam Shovel, Bear Creek, Klondike.

[TRINGTON.l

Open-Cut Mintng.

nd not permanent frost. Had the attempt been made to work the round at that time with the shovel the operations would have been Teatly delayed. In PI. XI, A, one of the frequent defects of the team-shovel system is apparent— the shovel idle and waiting- for cars, n this plant, after the shovel had worked to a considerable distance rom the bottom of the incline, the li-yard cars, 3 in number, were rammed to the bottom of the incline by horses and hoisted to sluice y a I5-horsepower hoist. The tramming may be more cheaply ecomplished, where there are several years' work ahead, by a small x'omotive in the pit running to the bottom of the incline or, under ivorable conditions, directly to the washing plant. Fig. 10 shows a Ian of the operation under discussion.

The tramming system illustrated by tig. 11, used at Galesburg, 111., i one of the shale pits of the Purington Paving Brick Company, is ansidered highly economical in steam-shovel work. As may be

w

I5°cable inch Spring switch

Hopper No. I

2 cars taken each time by incline

Switch to R R track

30 abore pit Incline 150' long

4empty J

ready for hopper No. t

I when filled go to hopper No. 2 mlumifaniiiimiini nam

Locomotive

I 90-ton steam shovel

Fig. 11.— Plan of steam-shovel operations, Galesburg, 111.

3en, the locomotive occupies a position intermediate between the vo trains of cars, which deliver two ways to the bottom of two lclines leading to the hoppers of the clay machines at each end i the pit. In placer operations, if conditions admit of dividing le water to two washing plants, this system is to be recomlended, as it allows of rapid delivery of the cars from the shovel. p. this plant the locomotive keeps 20 cars goin, each of 2 ards capacity, tramming them alternately, in trams of 6 and 4, wo ways to the ends of the pit, whence they are hauled, two at a pie, to the hoppers. When empty they run down and are switched pomatically to the empty tracks. The 90-ton shovel, of 5-}ard dippr capacity but fitted with 2-yard dipper, is ahead of the capacity of clay machines, but must be used owing to the difficulty of digging e firm shale which composes the bank. The actual yardage moved, rking nine hours a day, is 670, or at the rate of 1,488 yards in

Gtcavel And Placer Mining In Alaska.

[Bull. 2G3.

twenty hours. It is estimated that this is less than one-half the amount that could be handled were the shovel digging loose gravel. As it now works, the shovel is digging only one-third the time.

For moving up the cars within reach of the dipper as each one isj filled the device shown in fig. 12 is used. This was devised by Mr. W. S. Purington, and has been in successful use at this plant for five! years. The long cylinder, made with casting to attach to the shovel, I here shown on the near side, contains a piston of equal length, which! is supported on suspended track and wheel as it leaves the end of the cylinder. To the near end of the piston a cable passing over a sheave] is attached. The other end of the cable is hooked to the corner of the gravel car, steam is turned into the near end of the cylinder, and

t Steam

Body of steam shoi/et

Steam

fxhaust'f-

£

3-r Sheave

14 feet —

Trolley .Track

Fig. 12.— Pulling-up device for steam shovel.

as the piston travels back toward the forward end of the shovel cajl the gravel car is hauled by the cable an equal distance, from 5 to I feet, as may be required. Steam is then turned into the cylinder, allowing the piston to return and the cable to free itself; the cable iji unhooked and pulled by the car man to the following car and hooked in readiness to pull it along. The amount of steam and the time consumed in the operation are so small as to be almost negligible. Ity passing the cable around the body of the shovel car over a second sheave the cars on the opposite side of the shovel can be moved, when the relative position of the shovel is reversed.

Dipper chains are generally preferable to cables in placer operations, as illustrated by the experience of the shovel dredge in Solomon

purington.'j OPEN-CUT MINING. 77

River, elsewhere described. A link in a chain can be repaired where a wire cable can not.

The moving of the shovel as the digging progresses must be brought down to the most economical and rapid system possible. In the Galesburg operations wooden skids of 6-inch timber, 3 by 3 inches in dimensions, are hung from the jack frames by chains, and thus require no attention when the shovel is moved up. On these skids rest 6-inch blocks, 2 by 2 feet, on which the jack shoes bear.

In the Anvil Creek plant the present arrangement for dumping the pars at the sluice is unsatisfactory, and will be changed. Self -tripping two-way dumping cars will be substituted for the man who trips the cars. The sluice presents no new features. It is 500 feet long by 32 inches wide, by 36 inches high at the dump box, and narrows to 26 inches wide by 24 inches high, in 10-inch grade, and is furnished with angle iron rimes. The cost of digging, tramming, and dumping the gravel to sluice is said to be 12 cents per cubic yard.

The cost of steam-shovel operations in Alaska is not evident from the cost sheet (table 1, p. 38), as the figures there given cover the sluicing, often with purchased water, stripping, amortization, etc. In the Anvil Creek operation the actual working cost of digging the gravel, tramming and hoisting, and tripping the cars to the sluice box is given 3elow, as estimated by the superintendent, the figures covering 810 yawls in twenty-four hours, and including superintendence on the ground, labor, crude oil fuel at $3 a barrel, lubricants, etc.

( 'ost of steam-shovel work at Anvil Creek, Alaska, per cubic yard.

digging $0. 045

["ramming to incline 025

loisting 018

Jumping 011

Proportionate superintendence on ground, and incidentals 021

Cost per cubic yard 120

Figures showing the cost at the Galesburg plant, above referred to, ,re available in detail, for handling 17,422 cubic yards of shale per nonth of 26 nine-hour days, digging from 50-foot bank with a shovel fitted with 2-yard dipper, delivering to 20 two-yard cars trammed 2 gtys, 1,500 and 2,000 feet, respectively, to bottom of 2 inclines, misted by cable to hoppers at elevation of 20 feet above the track and lumped to hoppers.

Cost per month of steam-shovel work at Galesburg, III.

Bngineer, shovel $110. 00

crane man 85. 00

fireman, at 22 £ cents per hour 52. 65

trackmen, 17 cents per hour (shovel) 128. 85

locomotive engineer 80. 00

78 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Cost per month of steam-shovel ivork at Galesburg, III. — Continued.

1 switchman, at 20 cents per hour $46. 80

2 hoist men, at 20 cents per hour (hoist men dump the cars) 93. 60

1£ tons coal for shovel, at $2 78. 00a

ton coal for locomotive 26. 00:

1 ton coal for 2 hoists 52. 00

Total 752. 90

Cost per cubic yard 0432sj

Charges for superintendence, oil, waste, and incidentals are omitted from the above. Including these the cost is practically 5 cents a yard. The comparison below, however, is based on the figure of 10.0432.

If two of the trackmen be charged to the shovel, the digging operation and transfer from bank to car costs $0.0236, or 54.6 per centof the operation considered. In other words, the digging here costs little more than the long tram, hoisting, and dumping, and thus the object of using mechanical appliances is attained. A striking comparison is afforded by the cost of operating a placer which uses the car-and-incline system and the labor of men to fill the cars. If the duty of a man shoveling gravel into a car is taken at 12 cubi yards in nine hours, and the men are paid the lowest wage given the above tables, namely $42.85 per month, 56 men, say, would beJi eniplo3red filling the cars, and the monthly cost would be $2,305, or $0,132 per cubic yard, 5.6 times as great as that with the shovel, ol S4.8 per cent of the entire operation considered. In Alaska where wages for shovelers are from four to six times as great, the percent!! age of cost would be much greater.

Although the cost of 12 cents on Anvil Creek appears attractively low, it must be remembered that it does not take into account the> labor of shovelers cleaning bed rock after the shovel. This operation, unfortunately, can rarely be dispensed with, at least in por-i tions of the ground, and it will naturally increase the cost of getting the auriferous material into the cars. In some places m Alaska the slabs and leaves of bed rock must be scraped with brooms in order to recover all the gold. The prospective steam-' shovel miner should keep in mind the fact that a machine which will handle a large quantity of material, however cheaply, is of no avail unless it can succeed in extracting a large percentage of the values. 1

The steam-shovel plant at the junction of Bear Creek and Klondike River occupies the flood plain of the latter stream, a fact thai influences greatly the economical excavation and disposal of material, since both lack of grade for washing gravel and dump for disposal oi tailings must be supplied artificially.

This steam shovel (see PI. XI, B) digs in a pit 20 feet below the sur ; face of the flat. The dipper empties into cars which are pushed b) I hand to the foot of an incline and raised by steam winch to the plat

purington.] OPEN-CUT M1NIN(J. 79

form of the washing frame, where they are dumped by hand into a hopper. The material passes through a trommel, and the oversize falls into a self-dumping carrier and is elevated to dump. The undersize passes over tables and through sluices, and the lines are also raised by steam, a scraper being employed to secure dumping ground. There are, therefore, four distinct elevations, viz, by the shovel, the gravel by the tram, the coarse tailings by the bucket, and the fines by the steam scraper.

The pit in which the shovel works varies in depth from 20 to 24 feet. The gravel lies beneath 3 feet of muck, is generally mixed with considerable sand, and extends to bed rock. The material is well rounded and contains very few stones (but 1 per cent) that are over 18 inches in diameter. Considerable black sand is found in the clean-up. In spots the ground is frozen, necessitating the occasional use of steam points. Steam is conveyed across the cut in a covered steam pipe hung from a stretched cable. A schist bed rock, generally hard, is excavated for about 2 feet the shovel.

The shovel weighs 35 tons and revolves 360u upon a turntable. The dipper holds 1 cubic yard, and the machine has a capacity of 1,000 yards in ten hours, though this can not be obtained owing to inadequate cramming facilities. Its cost on the ground is about double that charged by the manufacturer. The boom, when horizontal, reaches 22 feet beyond the bow, but when at level of track only about 11 feet, three-quarter-inch cables are used in transmitting power. The faults )f cables in steam-shovel practice in inaccessible localities have been commented on above. The dipper contains no new features. Prongs ire added to save lip, the central one being longer than those adjacent. The machine has 3 engines and uses in all about 10 horsepower.

For conveying material three cars of 2 yards capacity each are used, mining on a 3-foot gage track with 16-pound rails. The cars are pushed hand to the foot of an incline, which has an angle of 22° and extends 00 feet, and thence elevated by cable connected to a 40-horsepower oist. Two hundred and fifty cars are usually raised in ten hours. )n reaching the platform the cars are dumped by hand and returned -*y gravity to the foot of the incline.

From the hopper into which the cars dump the gravel is fed into a evolving trommel 16 feet long and 3 feet in diameter supplied with

wrorm upon the inner surface and punched with holes varying from ne-half to inches in size. The rate of feed is regulated by hand,

gate being raised and lowered when necessary. Water is supplied

the trommel by a 6-inch longitudinal pipe. All oversize passes directly over a sheet-iron chute into a square hopper, from which it

lis by gravity into a self -dumping carrier and is elevated approximately 40 feet upon a dump. A 10-horsepower winch does this duty, t he hopper is furnished with a heavy iron gate, raised by the steam

80 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

winch running the self-dumping carrier, and is lowered by- its own weight. The fines (the material passing through the trommel) fall directly on gold-saving tables similar in design to those used on many gold dredges. These tables (see PI. XII, A), which are fed by two 4-inch pipes, are six in number (three on each side of the trommel) and have a gold-saving surface of 80 square feet. They are fitted with expanded metal and cocoa-matting riffles, which prove to be very efficient, the greater part of the gold being caught near the upper end of the first table. (See PI. XII, B.) The material then passes to a longitudinal sluice which consists of eight boxes 22 inches wide furnished with Hungarian riffles constructed of 1- by 3-inch inclined cleats capped with three-sixteenths-inch iron. The tailings are removed by a steam scraper and elevated upon a dump. The winch for the scraper is 30 horsepower and elevates 400 4-wheelbarrow units 15 feet in ten hours, seven-eighths-inch cable being used. It will be seen that the above double elevation of material must be costly, using, as it does, not only much power, but also additional men on separate winches.

The greater part of the water for sluicing, 300 inches, is brought by flume from Bear Creek. The remainder, amounting to 100 inches, is raised from the pit by a series of pumps. A No. 6 centrifugal pump raises the water to the foot of the washing apparatus, from which it is lifted 25 feet by a No. 8 centrifugal and used for sluicing. A 35-horsepower engine does the latter work. An additional pulsoineter pump is occasionally used in the pit.

The power plant contains two 60-horsepower boilers and one 50- horsepower boiler, wood being used for fuel. Sixty men are employed about the plant, the daily wage of the laborer being $4 and board. The men work two 10-hour shifts throughout the working season.

The above-described plant will undergo considerable change in the near future, improvements designed to effect greater economy being contemplated. It is planned to haul all material excavated a distance of 2,000 feet by locomotive, in trains of 6 cars, to a washing plant on the banks of Klondike River, where the ground is 8 feet below the upper edge of the pit, and then wash it by gravity water from Bear Creek. High water in the Klondike will greatly economize the handling of tailings, and it is hoped the full capacity of the shovel may be utilized.

A machine run on principles radically different from those described above is illustrated by a steam shovel on Eldorado Creek, in the Klondike region. In this case the use of a tramming system is entirely avoided by so arranging the plant as to allow direct dumping by the dipper into the sluice boxes. In this case the shallowness of the ground and the use of a 50-foot boom permit such an arrangement. The work lies in the crev.k bed proper and cuts are made longitudi-

U. S. Geological Survey

Bulletin No. 263 Pl. Xii

A. Stationary Washing Plant, Klondike.

A-

B. Cocoa Matting And Expanded Metal Riffle.

UKiNGTON.] OPEN-CUT MINING. 81

iall3r along- the stream, the sluice boxes being" moved every three or bur days, following the progress of the shovel. This practice alone nvolves both good and bad features. The practice of dumping lirectly into the sluice is, theoretically, much to be desired, embodyng, as it does, only one elevation of the gravel, an arrangement which onsumes the least power and time — two all-important factors. The Qoving of the sluice boxes, however, in this case consumes much inn — from one to two days for each move — and, wages being $6 a lay and the season very short, constitutes a serious drawback, greatly educing the capacity of the plant. The boom of the machine, as tated, is 50 feet long and hoists the gravels 30 feet above the cut. If n arrangement facilitating the moving of the boxes could be devised, o as to avoid the long delays caused by this operation, a very satisfacory result might be effected. Such a system requires a relatively hallow bank, however, and it is doubtful whether it is available for team-shovel operations in general.

In this instance the gravel to be taken out is frozen, and continuous hawing must accompany the advancing work. In this work 15 steam joints are driven into the bank to bed rock, where the}" remain wenty-four hours, the process consuming during that time 3 cords of rood. A 25-horsepower boiler is used for this duty. (See PI. XIII, B.)

Water is very scarce at this plant and is used repeatedly, being raised fom the pit by a centrifugal pump and carried back to the sluice oxes in a flume. The pump also serves to drain the pit. The sluice oxes have a grade of 9 inches to 12 feet, but, with the water at hand, re unable to keep pace with the capacity of the machine.

I The shovel carries a one-yard dipper operated by chains. It is aimed that 1 cubic yard is moved every two minutes. Bed rock of slaty nature is taken up to a depth varying from 2 to 5 feet. The problem of disposal of tailings is a difficult one and has not 3en solved economically. A steam scraper is used and all tailings ust be scraped to one side and elevated. Not only is the expenditure t wood an item, but a man must be constantly attending the scraper hile another handles the steam winch.

A tramming system which would convey the material to be washed I such a point as would admit of the disposal of tailings by gravity, |en if a thousand feet or more distant, would be a more economical irangement, saving, as it would, not only all elevation of tailings, lit also all delay in moving the washing apparatus. Ten men are employed about the plant each shift, occupied in sraping tailings, forking gravel in dump box, running shovel, Blending steam points, and in cleaning bed rock at places where the coper could not effectually work. Bull. 263—05 6

Gravel And Placer Mining In Alaska.

[Bull. 203.

The shovel is moved by rollers running on skids, power being obtained from the shovel winch. The dipper is furnished with soft

steel prongs which wear very rapidly.

Drift Miking.

Introduction.

Northern gold-gravel deposits, that are sufficiently rich to war! rant the method, can generally be exploited by- drifting beneath the overburden at all times of the year. In drift mining creek deposits the gravel is hoisted through shafts, and where bench gravels are worked it is generally trammed through adits. In all portions § of the interior of Alaska and in

1 the Klondike the drifting of aurifte erous gravels has been carried § on with fully as much activity ini

2 the winter as in the summer. As a may be seen by the cost sheet, o the expense of winning the gold by winter drifting and spring thaw- [ ing is greater by over $1 per cubic yard than that of summer work. This increase is due to the necessity

of rehauling and, in many cases, oi<

rethawing the dumps in the sepa-i

rate process of sluicing. In con

sequence, only the richer ground

running from $6 to $10 to thi1

cubic }7ard, can be profitably j

drifted. The price of labor dur* 1

ing the winter in the interior i

only 25 per cent less than in sumij

mer, so that this does not afford

great offset to the increase of cos j,

from other causes. In Sewar 9

Peninsula, where the price fo j

winter labor is only $2.50 a da 1

and board, as against $5 in summer 9

it would seem that winter drifting can be undertaken more generall ]

than heretofore. A reliable operator of Nome is of the opinion thf

Purington.]

Drift Mining,

winter drifting operations should be continued in that vicinity where timbering is necessary but thawing is not, and where the gravel can be trammed to surface through adit for $3 per cubic yard, including all expenses of extraction and sluicing-up in the spring. This is less than double the cost of drift mining in the Forest Hill divide region of California, where conditions are eminently favorable.

Neglect to sample is the worst possible practice, as many lamentable failures have resulted from overconfidence in the value of the ground taken out, and the miner who confidently waits for the big wash-up before thoroughly knowing the amount of gold in the material he is handling is frequently doomed to disappointment. The method of sampling the dump, given under the heading" "Hydraulic mining" (p. 118), is to be highly recommended for all work of this nature.

Where timber is scarce and costly, and wood for fuel has to be hauled from a distance, it is advisable to consider the entire abandon-

Fig. 14. — System of opening drift mine.

ment of attempts at winter work. The amount of gravel which can be hauled is less, and the cost per cubic yard is greater. The time spent in sluicing the winter dump ma}r frequently be more profitably employed in preparing for the summer. The ordinary small rig for drifting operations without timbering is shown in fig. 13.

Drifting And Timbering.

Drift mining, whether the workings are approached by shaft or adit, can be most economically conducted by adopting the system which proved so successful in California. The mine is opened by a main tunnel or runway, 6 by 6 feet, which generally requires timbering, with logs 8 by 8 inches, 6 feet long, the sets having 5-foot centers. This runway is continued out to the end of the block of ground which it is proposed to work, say from 50 to 100 feet in ordinary Alaska operations. It is assumed that the runway occupies the longer dimension of the ground and approximately the center of the streak, say 75 or 100 feet in width. From the main tunnel drifts are run ransversely each way to the outer edges of the pay. These generally lo not require timbering in frozen ground. Fig. 14 illustrates the ystem of main runway and drifts. The gravel can now be breasted )ut, a face being carried the full width of the pay and the work being continued in two or more of the drifts, as desired, the breasts being lways carried toward the shaft or adit mouth. The drifts may be

Gravel And Placer Mining In Alaska.

t

[Bull. 263.

timbered either with sets, where ground is heavy, with single posts and caps in moderately firm ground, or left entirely un timbered, as in solidly frozen ground. Fig. 15 shows the manner of timbering closely and rock filling behind when breasting out faces of loose gravel in the Hidden Treasure gravel mine in California. The sketch is made up in part from report of Mr. Ross E. Browne/ and in part from the writer's own observations. The system oi filling behind with quartz stones is impracticable for Alaska mining; instead of this timbers should be pulled and the ground allowed to cave. This form of timbering is in use in the drift mines of Solomon Hill, Klondike, except that instead of separate base blocks sills are used. Fig. 16 shows a portion of the drift operations which were prosecuted on Solomon Hill in the early years of the Klondike exploita tion. The plan of the workings is here reproduced by courtesy of Mr, George T. Coffey, manager of the Anglo-Klondike Mining Company'}

Floor of channel

Fig. 15.— Hidden Treasure system of timbering drift mine.

operations. The drifting operations in the southern portion of th ground are still in progress. PL XIII, B, shows the mouth of ori of the adits leading to the operations.

The main adits are timbered with 4-inch timbers, in sets with 5i-fo< centers, at a cost of $1.75 for framing and putting in per foot of tui j nel run. The entire cost of driving the tunnel 5J feet high, includir steam thawing, excavating, tramming, timbering, and laying track 12-pound rail, was $6.25 per foot. Transverse drifts were run fro j the main adits, and the ground was always breasted out in the directk f of the adit mouth. The irregularity of the workings in a portion the ground is accounted for by the fact that a certain amount of unsy tematic work had been done previous to the purchase of the ground 1 the present company.

The ground is solidly frozen and had to be thawed by steam point The rate of speed with which the work was carried on may be judg from the fact that two men, working a shift in running a strain

a The ancient river beds of the Forest Hill divide: Tenth Ann. Rept. State Min. Cal., 1890, p. 4

U. S. Geological Surve

Ulletin No. 263 Pl. Xiii

A. Adit To Drifting Operations.

B. Thawing Ahead Of Shovel, Eldorado Cree

Purington.]

Drift Mining.

tunnel after the points had been left in fourteen hours, averaged Sifeet, including taking- out the points, putting in timbers, keeping up the track, and driving in other points to a distance of 5 feet. The average height to which the gravel was taken out in a representative block was 4 feet. PI. XIV, A (p. 86), shows the remnants of old drift timbers in ground which has been hydraulicked subsequently to the drifting of the rich bed-rock pay. The cost of mining was $5.50 per

Fig. 16. — Plan of drifting operations on Solomon Hill, Klondike.

quare yard of area worked. In drifting out the ground it was found hat three points in a face 6 feet wide, allowed to thaw twelve hours nd then withdrawn, the ground being wC sweated" twelve hours longer, would thaw all the ground. The sluicing was conducted in the ordinary way of piling up the dump and afterwards caving and hydraulickng with a nozzle into the boxes. The actual working cost of washing yas about 18 cents per square yard of area worked.

86 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

In drifting operations on a bench of Anvil Creek, Seward Peninsula, a main long adit was run 4 by 6 feet 6 inches in the clear, at a cost of $4 a foot, untimbered, for the entire width of the ground in a direction transverse to that of the creek. This was 500 feet in length and was 10 feet below the surface of the schist bed rock. The average depth of the ground was 20 feet, being 2 feet of muck, 11 feet of wash gravel containing almost no gold, and 7 feet of pay dirt, the last consisting of 5 feet of pay gravel and 2 feet of bed rock, which contained the best pay. This was the thickness drifted. The adit served as a drain for the workings. The ground was only partially frozen, and it is likely, as has been found in parts of the Alaska interior, that the constant draining of the ground assisted in a gradual thawing of the frozen parts. From the end of this main adit, a long tunnel (600 feet) was run for the length of the ground which was to be drifted, at a level of 8 feet above that of the adit floor. This was timbered with 6- by 6-inch posts, 8- by 8-inch caps, sets with 4-foot centers, lagged with 2- by 6-inch plank, top and sides. From this long drift cross drifts were run in a direction parallel to that of the main adit, at intervals of 100 feet, and with lengths of 40 feet on each side of the main longitudinal drift. The ground was then breasted, carrying a 40-foot face toward the adit. The Hidden Treasure system of timbering, using false sets, was employed. Track was laid both in the main adit and in the upper workings, and cars of 21 cubic feet capacity were employed in I tramming, 4 in the main adit and from 15 to 20 in the upper workings. The stopes never exceeded 20 feet in back and forward dimensions. The timbers used were 8- by 8-inch posts, 7 feet long; 10- by 10-inch caps, 11 feet long; 5-foot centers, all ways, between posts. Boards were laid down to shovel on. The ground was so heavy it was found impossible to save the timbers, but the track was all recovered. In extracting 21,000 cubic yards, timbering cost $14,000, with lumber at $50 per thousand.

The gravel was trammed to surface and distributed on a long dump 40 feet on each side of a previously constructed 24-inch .sluice 500 i feet long. As usual, planks were laid on top of the sluice, and when spring opened the gravel was caved and horse scraped into the sluice. In distributing the gravel on the dump 3 men and a horse scraper had to be employed most of the time in keeping the snow off', on account of especially heavy snowfalls when the work was being done. When completed, the dump measured 700 by 80 by 20 feet, approximately. The drifting work consumed nearly eleven months, and the sluicing about two months, being delayed on account of frost in the gravel.

Labor employed averaged 45 men in two shifts of ten hours, at i winter wage of $2.50 a day and board. A shift in the drifting operations consisted of 10 men shoveling into cars, averaging 8 cubic yards to the man; 3 to 4 trammers took care of the dirt shoveled. In sluic-

U. S. Geological Survey

Bulletin No. 263 Pl. Xiv

' liiil iJR '

J. Old Drift Timbers In Hydraulic Pit, Klondike.

B. Application Of Steam Point In Open-Cut Work.

[ibington.] DRIFT MINING. 87

rig, 10 men and two 2-horse scrapers were used to a shift. The iroduct of the operations was $160,000; and the cost, including preiminary prospecting, was 59 per cent of the output. The work was one in 1901-2, and the opinion was given by the operator that the ost could be decreased 20 per cent under present conditions.

In drifting operations on high benches lying between Anvil and )exter creeks near Nome the gravel must be hoisted through shafts. t is said that powder is efficient in extracting the frozen ground, "his is contrary to experience in the Alaska interior, and is doubtless ue to the fact that the gravel is not nearly so solidly frozen. In fact, b is said that the powder is used for only a portion of the time, rom the main shaft, which must be in some cases 230 feet deep to each the second pay streak, a drift is run the length of the pay round. From this, transverse drifts are run at alternate intervals of 0 feet in each side of the main drift. Some operators sink the shaft n the side rather than in the center of the ancient channel, as by this aethod the shaft is less likely to u squeeze." The shafts are 3 by 6 eet, timbered with 2- by 12-inch plank laid up on the sides, with 2- by -inch timbers set vertically on the corners inside.

The face can be carried from 50 to 100 feet in length in the winter, s the constant slight freezing renders the gravel less heavy. In sumler, on the other hand, the ground must be worked in small blocks. Vith the methods of timbering in use, 6- by 6- to 10- by 10-inch sawed lost are put in, on base block, and with a short 4- 12-inch plank ap, posts having 3-foot centers in all directions. A space of 3 sets in width is generally carried before the ground is allowed to cave. When he ground is ready to cave a bulkhead is nailed to the second set, the fibers are pulled with ropes from the third, and the caved ground is aught by the bulkhead. The breast is then carried forward as before, (o lagging is used except in the shaft and the main runway. In summer work the area of bed rock exposed in one stope rarely exceeds 10 eet square.

In sluicing tlie dumps from winter operations on the high Anvil ►enches, the expedient is adopted of building small dams of sod and recting snow fences behind them to catch snowdrifts, so that sluicng water may be afforded in the spring from the melting snow. The remarkable phenomenon of deep-lying pay streaks on the Anvil enches has been considered by Mr. A. J. Collier a in his geological count of the Nome district.

On Eagle Creek, in the Birch Creek district, an interesting drifting Operation was seen. It is especially difficult to work the creek claims iy drifting on account of the partially thawed character of the gravel. L bed-rock drain was run in winter at one side of and parallel with the

a The placer deposits of Seward Penuisula: Bull. U. S. Geol. Survey, in preparation.

88 GRAVEL AND PLACER MINING IN ALASKA. [bull. 26l

pay streak, and low enough to drain all the ground which it was proposed to work. The drain was covered and lagged with poles and! thus rendered permanent. A shaft was then sunk at the lower end ofi the ground, 4 by 8 feet in dimensions and 20 feet deep. This waa timbered only for the upper 14 feet, and was sunk in three days by 2j men. A tunnel was then run upstream the length of the ground, wide enough to admit 8-foot caps. Posts were 5 feet long, all timber] being 9 inches square. Sets had 4-foot centers, and the tunnel was lagged overhead with 2-inch flattened poles. A set of timbers delivered cost $4, there being 34 caps to a cord of wood. Lateral drifts! 8 feet wide were driven at intervals of 8 feet, 4J feet in thickness oi gravel being taken. The gravel was wheeled to the shaft and windlassed to surface, about 25 cubic yards being raised in ten hours. The lamentable lack of any tramming arrangement for transporting the gravel to a distance resulted occasionally in the caving in of the ground from the added weight of the dump. The gravel so laboriously] raised was thus lost. Some idea of the difficulties of operating on Eagle Creek may be seen from the following figures: Wood was $10 a cordj not excessive high; lumber, $180 a thousand; and freight-packing rates from Circle on the Yukon, 25 cents a pound in summer and 8 cents in winter. Considering the remoteness of the district, the won carried on was remarkably good and systematic.

Thawing.

One who has never visited the interior of Alaska finds it difficult to conceive the formidable condition of solidly and perpetually frozen alluvium which is there encountered by the placer miner. The quantity of water in the form of ice which occurs in the frozen gravel averages about 25 per cent; while in the overlying fine, black silt which forms the overburden the quantity of ice varies from 50 to 75 per cent. Whatever may be the physical composition of the material, it forms a mass as solid and as difficult to penetrate as solid stone, andj can be disintegrated only by exposure to the sun's rays or by the longcontinued application of some form of energy artificially applied.

In any open-cut operations the dense blanket of moss, from 12 to 18 inches in thickness, which covers the frozen ground, must be broken into and turned over either by adzes or plows before the action of sun and water can take any effect on the underlying muck. As has been said, this effect is remarkably rapid when the water is allowed to run over the exposed black and icy mass.

A curious condition exists in the treeless areas of Seward Peninsula. Wherever a growth of stunted willows occurs, the ground beneath is found to be thawed, and wherever the willows are replaced by moss the ground is frozen solid. The rule is not without exceptions, but has been found to have rather general application. The distribution

Pubington.] Drift Mining. 89

of the willows and moss-covered patches in the creek bottoms and along the low valleys appears to be entirely irregular. For further notes on the frozen and half-frozen conditions existing in the interior reference may be made to the matter presented under the heading, "Prospecting."

Drifting operations in the creek deposits of the Klondike, Birch Creek, Fortymile, and Fairbanks districts of the interior are nearly always carried on in solidly and perpetually frozen ground. A necessary accompaniment of the work is the thawing of the ground by artificial means. Mr. Greenleaf W. Pichard has thoroughly investigated for this report the possibilities of using any form of the electric furnace for thawing the frozen gravel, and has reached the conclusion that electric thawing is impracticable. The thawing of ground which lies open to the air, by the combined agencies of sun and water, will be considered under the heading "Hydraulic mining." Artificial power, through the agency of the steam point, is only in rare cases applied in open-cut work. The Klondike district afforded a few examples of this application of power, notably in connection with dredging operations on Bonanza Creek, the steam-shovel operations on Bear Creek, and in two open cuts on Upper Dominion and Hunker creeks. PL XIV, B (p. 86), shows an application of the steam point to open-cut mining on Hunker Creek. It is difficult to determine the efficiency in open work, as, naturally, a portion of the thawing is done by the sun. From the data collected, however, it does not appear to be any greater than its underground efficiency, which will be presently discussed.

The method of thawing gravel underground by wood fires is expensive and, unless the conditions are very exceptional, is not used in those districts where transportation facilities permit the bringing in of boilers.

According to experience on Deadwood Creek, Birch Creek district,

the efficiency of a wood fire in creek ground was as follows: A fire

taking three-fifths cord of wood (at $12 a cord) is built against the

Pace of the bank. The pile of wood will be 18 inches wide, 2 feet

ligh, and 25 feet long. Stones are laid up over the pile and a space

s left to light the fire. The fire is lighted at 5 p. m. and left to burn

intil 8 a. m. the next day. The stones, which quickly get hot, are

egarded as most efficient in thawing. On a 4-foot thickness of pay

;his amount of fire will thaw, in the time specified, from 5 to 6 cubic

v arc Is of gravel. This is at the rate of 9.2 cubic yards thawed to the

ionl of wood, which is considerably less efficient than the method of

gnawing with steam. Time, delays, and awkwardness of the method,

jnoreover, make wood-fire thawing the most expensive that can be

jtdopted. The figures per foot for shaft sinking range from $3.16 to

Iip7.50 in taking gravel from prospect shafts. The efficiency given in

Gravel And Placer Mining In Alaska.

[Bull. 263.

the above-cited case on Deadwood Creek appears to be very nearly the same as that given by Mr. E. D. Levattt for the operations in eastern Siberia.

t

7

a

E

o

ly steam hose machinery steel

jn £ /

to

]

The direct application of jets of dry steam to the gravel bank through the agency of driven pipes has been found to be the most etii-

aL'Or en Siberie orientale. The formula used is: Each breadth of 1 inch of wood applied at the foot of the face thaws an equal width oi gravel.

pjBiNGTON.] DRIFT MTNING, 91

>ient method in general practice for thawing frozen gravel. The imount of moisture contained in steam can be judged by the color of l jet of steam issuing from a small brass pet cock. If it is transient or whitish near the orifice it contains less than 2 per cent of moisture; if pure white, the moisture is above 2 per cent.

Fig. 17 shows the details of the steam point and some of the fittings vhich its use entails.

In creek claims exceeding 15 feet in depth where solidly frozen ground occurs, as, for example, in the new Fairbanks district of Llaska, the method of drifting with the use of the steam point is as folows: A 20-horsepower boiler, capable of running 10 steam points, is put the ground, and frequently one or two extra long points are provided or sinking holes. These long points, from 10 to 12 feet in length, are ot so strongly made as the 5-foot points used in the drifting operaions. In some cases pieces of one-half-inch hydraulic pipe are used, 'he point is set up on the ground and steam or hot water is turned n. The time for sinking a hole by this method to bed rock is from wenty-four to forty-eight hours. If large, flat stones are encoun- Bred in the gravel underlying the muck it is sometimes advisable to se strong, specially made points to prevent breaking. The average radius of a vertical shaft thus thawed by a single point is 2 feet, and le hole when cleaned out has a cylindrical or tube shape.

If timbering is required after the shaft is sunk it is generally found sat the hole will thaw sufficiently to allow the shaft to be carried 4 by

feet or 4 by 6 feet inside the timbers. As a rule, however, winter hafts are not timbered. When bed rock is reached a tunnel or runray is run for a distance varying from 50 to 100 feet from the tunnel ingthwise of the claim. From this central drift, which is generally [inhered, lateral drifts are run to a distance not exceeding 50 feet, or rom this down to 10 feet, or the width of the pay streak. Two tunels parallel with the central runway are carried at the ends of the ross drifts and connections made from them to the shaft. These are a rely timbered.

The frozen condition of the overburden allows a firm roof to stand without timbering while the gravel is being extracted. This is a great d vantage and in part offsets the difficulties attending the breaking p of the frozen gravel. The ground is now ready for working. The rifts and main ways are run as low as possible in cases where the ip&y i thin, but a height of feet is the lowest that can be worked with conomy.

During the night shift sufficient gravel is thawed to occupy the len in extracting it in the daytime. In handling, not only the picklg and shoveling from the bank must be allowed for, but the wheeling ) the shaft, the time of return to the face, and the hoisting of the

92 GRAVEL AND PLACER MINING IN ALASKA. [bull. 268

gravel to the surface and conve}Ting to the dump. The face expose( b3T the cross drift at the far end of the runway is worked back towar the shaft, and the gravel is trammed in wheelbarrows to the shaft anc hoisted. Points 5 feet in length are used to thaw the gravel, and are generally used in "batteries" or "crossheads" of four (see fig. IT, p. 90). The points are supplied with steam from a orosshead of irongas pipe, three-fourths inch in diameter, fitted with elbows and short pieces of one-half inch pipe leading to the steam hose, to which the points are attached. The valves are generally set in these short pieces of pipe. The points are driven in with a mallet b}T the point man working on the night shift. The points are left in the bank from ten to fourteen hours. The thawing is nearly always done on the night shift, the onhT men occupied being the point man below and the fireman at the boiler above. Each point thaws a block of gravel on an average 6 feet into the bank, 18 inches on each side of the point and -1 feet high. The crosshead is laid on the floor of the drift, at a distance of 10 feet away from the face, and the steam hose connecting each cock of the crosshead with the individual points must be long enough to reach the desired distance for placing the point in the bank. The cross pipe to which the hose clamp attaches the hose, should be carried through the steel head and brazed on the opposite side so that it will not break oft' by a chance blow from the mallet.

It is considered good practice as a rule to start the points with hot water turned through the hose. The points must be driven carefully and slowly, and for 10 points distributed along a face the average time needed is from one to three hours. The amount of steam required for each point has been found to vary in amount from 1 to 2 boiler horsepower. One and one-half may be taken as a safe average. The amount of gravel which a point will thaw appears to vary with the length of the point, and this is regulated somewhat by the character of the gravel. The 5-foot point has been found the most economical size for the small operator.

A typical illustration of the efficient} of the points in the Fairbanks district is the experience at No. 8, below Fairbanks Creek. Points of Dawson manufacture, 5 feet long, costing $15 each laid down, were used in crossheads of four. They were put in at distances of from 2 feet 6 inches to 3 feet apart. The points were started with hot water, and it took three hours to drive them in. A 12-horsepower boiler supplied the steam for 10 points, three-fourths of a cord of wood being burned on the night shift, when the thawing was done. In twelve hours the 10 points thawed a block of gravel 30 feet in length by 5 feet in height by 6 feet into the bank— an average of 3.3 cubic yards to the point.

The above is a little high for the average duty in the Fairbanks district, but is low for the Klondike creek drifting operations. A typical

U. S. Geological Surve1

Bulletin No. 263 Pl. Xv

A. Drift Mining On Fairbanks Creek.

1',. Hydraulicking, Silver Bow Basin.

lirington.] DRIFT MINT NG. 93

esult on Hunker Creek, where li to 1£ horsepower was usd for each i-foot point running ten hours, was 4£ cubic yards. PL III, B p. shows a winter drifting operation in the Klondike, and PI. CV, A (p. 92), shows a drifting operation during summer on Fairanks Creek. PL XIV, /?, shows a battery of steam points thawing round in the open in preparation for excavating by a steam shovel, liree cords of wood, at $13 per cord, were burned in twenty-four ours to generate steam for operating 15 of these points 10 feet long, 'hese thawed ground 14 feet deep to bed rock. As 4 cords of wood mre burned in addition on the steam shovel, and 20 men, at $6 a rere employed in the twenty-four hours to get out less than 500 cubic ards a day, the operations were not economical. In connection with dredging operation the thawing by means of steam conducted through as pipe in 11-foot lengths was estimated to add 40 cents per yard to tie ,cost of working the ground.

The only drifting and steam-thawing plant at Nome gave an effiiency for each point of only cubic yards. The points were using i this case a little less than 1 horsepower each and were run only for ight hours. Moreover, the gravel was small and was mixed with mch ancient beach sand, which in a frozen condition is extremely ifficult to thaw with steam.

The method of thawing with hot water by means of a force pump 3t in the underground workings, which forces hot water through a mall nozzle against the bank, has been tried successfully in the Klonike district. At a claim on Gold Run, where it was desired to extract

3- foot pa}r streak of gravel capped by 27 feet of barren gravel at a epth of 50 feet below the surface, a small force pump of the ram patirn, with outside packed valves, was placed in the main runway near tie shaft. It drew water from a 6-foot sump near at hand, to which tie workings drained. The pump had 4-inch intake, 3-inch discharge hoked to 2£-inch, and the water was pumped to the face by means of otton hose and discharged through a 1-inch brass nozzle at 40 pounds ressure. Six thousand gallons of water were used over and over, nd by discharging the exhaust from the pump into the suction the rater was kept at a temperature of 150° F. In a shift of ten hours le pump, using 30 horsepower, thawed and broke down ready for the bovelers 175 cubic yards of gravel. This is vastly superior to the verage Klondike dut}r of the l-horsepower steam point, even allowlg 4 cubic yards to the point, as the 30 horsepower would supply only 0 points and the maximum duty would be 80 cubic yards.

Only under certain very favorable conditions, however, can the hotrater method be used. There must be no silt in the gravel, otherwise le water becomes thick and can not be settled in the sump. If the ed rock is in large flakes, and the pay sinks into it, the hydraulic

Gravel And Placer Mining In Alaska.

[bull. 263.,

method is inefficient in thawing the valuable ground. The method is worthy of the serious attention of the Fairbanks placer miners, however, as will be pointed out in the discussion of that district (p. 97).

Hoisting.

For hoisting and conveying, say to a distance not exceeding 200 feet, the Dawson self -dumping carrier, with accompanying bucket, cables, etc., and steam hoist, must be used in order that the most economical work per man employed can be done. This device, which is shown icj fig. 18, is without doubt the best system of handling gravel from a shaft of shallow depth now in use in the Northwest. It is strong and compact, and is simple in operation. Those parts which by their position receive the most strain and iar can be made sufficiently durable tq withstand hard usage.

Fig. 18. — Dawson self-dumping carrier.

No springs are used in the construction, for the reason that at lo temperature, say of 40° F. below zero, metals are very brittle, anc the constant jar, a necessary accompaniment of the work of thif apparatus, renders springs and any light metallic member unsafe.

As fig. 18 shows clearly the construction of the carrier, only a fev words need be said of its operations.

It may be stated that three distinct operations are accomplished two of which are performed by the carrier, the third being effected bj an auxiliary rope used in dumping the bucket. The first consists ii engaging the bucket as it arrives from the shaft and carrying it to tb dump box, the second in returning the bucket to the head of the shaf and there dropping it to the bottom. As the carrier returns dowi

?urington.] DRIFT MINING. 95

the seven-eighths inch cable, the hook to which is attached the bucket occupies the position indicated by the solid line. The cam, A, lies horizontally and is held firmly in this position by the dog, B, the weight of the bucket pressing the notch of the cam against the point ;>f the dog, f. When the carrier reaches the head of the shaft the 3nd, c, of the dog strikes the block, D, and frees the point of the dog from the notch of the cam. The front of the cam now occupies the position indicated by the dotted line, and, as the bucket sinks into the shaft, is pressed against the block, since the carrier tends to move backward. Thus as the bucket sinks with the hook on the one-half inch cable the carrier is held firm.

As the bucket rises from the shaft or pit, the strain is toward the engine, and the lower end of the dog, e, still prevents the apparatus from moving.

When, however, the cam, A, by the upward movement of the bucket, reaches the horizontal position indicated by the solid lines, the point of the dog, y, jumps into the notch, lowering at the same time the point, e, which allows the carrier to move up the sevengighths inch conveying cable, and also once more secures the cam in its horizontal position.

The block attached to the cable is held in a vertical position by a suspended log or block, which insures its engaging with the dog.

By this system of working, if the self-dumping rig handles 250 of the 30-pan buckets in ten hours or, roughly, 60 cubic yards, the plant will necessitate the employment of 12 men, namely, 2 firemen, 1 hoist man, 1 point man, and 6 men shoveling and wheeling, beside the foreman. The ordinary set-up of the self-dumper is shown in fig. 13. The boiler used for generating the steam for points at night is used for running the hoist in the daytime. In running from 15 to 20 points at night it will burn a cord of wood, and. in hoisting in the daytime will burn from one-half to 1 cord more. The total daily twenty-four-hour expense can not be brought below $130 and will probably amount to $150. It is evident that with such a plant the enor of the gravel must amount to at least $2.60 to the cubic yard to ay any profit at all, exclusive of washing in the spring, and should e 4 cents to the pan, or $5.20 to the yard, to pay a profit which condensates for operating in so remote and expensive a country. The ost of washing in the spring is in general from 50 cents to per iubic yard.

The winter dumps are piled in a conical heap around the gin pole, :o which the trolley cable of the self-dumper has been attached while pie dumping is in progress. In laying out the space for the dump, he string of boxes in which the gravel is to he washed during the ollowing spring is so laid that it will bisect the proposed cone, having ts proper grade and length. When the spring opens the dump is

96 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263J

easily shoveled into the boxes, from both sides, beginning at the lowest point and working upward. Boards are generally laid over the top of the boxes, and a portion of the gravel rests on these. The boards are taken off as the work of shoveling in progresses.

The expenses of winter work are much greater than those for summer, and the tenor of the gravel must in consequence be much higher. In the first place it is to be remembered that the gravel dumped in winter must be all rehandled in the spring. In thawing also the amount of steam used in winter is greater than in summer, and al] pipes and hose conveying steam both above and under ground must be coated with asbestos or other nonconducting material. On the other hand, labor is generally cheaper in winter than in summer, and the possibility of striking thawed streaks of ground is much less.

Drifting In The Fairbanks District.

As has been stated, the only mining practiced at Fairbanks is creek mining. In the open season, although the bulk of the ground can be worked by drifting, a smaller proportion is workable by open cutting. B}' far the larger portion of the ground must be worked by drifting on account of the depth to bed rock and, in many cases, the thinness of the pay. The ground is in the main frozen, but thawed streaks occur. The gravels are of the angular and subangular character which marks all the gravels deposited in recent time in the northwest. The angularity is more pronounced than in the Birch Creek district or the Klondike.

One characteristic feature of the Fairbanks gravel has an important bearing on the method of thawing the frozen gravel. This is the fact that while the la}er of so-called muck is comparatively thin, from % to 7 feet in the workings on the creeks themselves, exclusive of the slopes, the gravels, which are from 6 to 15 feet in thickness, do not carry pay throughout their section, but only in the lower part. The pay is sometimes as thin as 6 inches in the gravel, and rarely exceeds! 8 feet. It is then frequently necessary to take only a portion of the: gravel down, and to run the drifts as low as possible, i. e., not to exceed 3£ feet. To do this economically, and so that the top and bar-i ren gravel will not be continually caving and falling during the drifting, the ground must either be timbered or the method of steami thawing must be abandoned. Another reason why the method oi steam thawing has a limited application in the Fairbanks district is the fact that the gravel is very argillaceous in its pay portion, and the thawing and drying with the steam result in a baking of the ground. Thus the gravel which was frozen becomes in its dry state cemented, and the difficulty of getting it out is not avoided but only lessened. A

Thawing by means of hot water driven through a force pump and conducted to the bank by means of cotton hose and piped against the

PJBington.] DRIFT MINING. 97

bank by menus of a small fireman's nozzle is the most successful method pphich has been so far tried to thaw ground under the above-mentioned jonditions. As regards the heating of the water, the system adopted it Fairbanks is to conduct the exhaust steam of the pump back into lie suction of the pump as it draws water from a sump alongside of it. rhis has been found more effective than simply turning the exhaust ripe directly into the sump itself. The water used is sometimes supplied in sufficient quantity from the mere seepage from the ice mixed vith the thawed gravel. But sometimes it will have to be introduced n the pit in small quantity. On the other hand, especially where hawed streaks occur naturally in the gravel, the water must be pumped >ut. This is done by the same pump used for the hydraulicking, with- >ut changing its position.

This method of thawing by hot water piped against the bank has two advantages. The strongest appears to be the fact that gravel thawed )y this method can, as it were, be selected in the face, and no higher gravel than may be profitable need be taken down. The portion of he gravel above the part taken down remains solidly frozen, and conequently the roof of the drift or wide stope does not cave any worse han does the roof of solid muck in drifting operations where all the gravel in its complete vertical section is extracted. Another advanage is that the gravel is moved from its original position farther than )y steam, and if it contains clay the clay has less opportunity to bake .nd cake than with steam thawing, and the amount of hand work in ricking down the gravel is lessened.

A serious objection to thawing by hot water may justifiably be raised

n cases where the bed rock consists of large slabs of schist, into which

he gold sinks from 1 to 4 feet and even more. In such a case the

yater can not be piped to reach all the frozen gold-bearing material.

Although I am not aware that a combination of the hot-water and

iteam-thawing methods has been tried in such a case as the above, it

eems not impossible that such a combination would be the most eco-

lomical. On the other hand, where the bed rock consists of finely

pmminuted schist or softened, thoroughly rotten rock, even should the

[old be found in it to the depth of 2 feet, there can be no valid objec-

on to the hot-water hydraulicking method. In the Nome district

f Seward Peninsula, where the hot- water method was tried, it was

und that the water finally became too thick with sediment to be used

the pump, and the system was abandoned.

A minor recommendation for the use of the hot-water method is the ct that all the unpleasantness of the steam method, which fills the orkings with steam, creates dampness, etc., is obviated, and the walls id roof of the drifts are dry, while ditches cut in the bed rock on rade to the pump sump can be so cut as to prevent the floors from Bull. 263—05 7

98 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

being wet. The obscurity of the air in the workings by steam, especially in the early part of the day shift, is frequently a source of danger, as the roof can not be watched so closely as it could were the air clear, and consequently slabs of the roof that are ready to fall can not be easily seen, so that the liability that men will be crushed is greater.

I should especially recommend the method of hot-water thawing to the consideration of the miners of Cleary and Pedro creeks, while on Fairbanks Creek, as hitherto developed, the method of thawing with steam points seems more applicable.

In the Fairbanks district shafts sunk for work in the summer time are in nearly all cases timbered, either wholly or partially. In very, deep shafts, as, for example, on the left bank of Cleary Creek near the junction with Chatham, where 40 feet or more of solid muck is encountered, timbering does not appear to be always necessary throughout the whole of the shaft. The muck forms a wall which resembles in its consistency a wall of solid ice, and in working throughout a season of four months, with the shaft in constant use, there will be little caving of the walls. All shafts that extend 20 feet or less, however, especially where gravel composes half or more of the section — shafts intended for working out a block of ground, conducting steam] connections, pump connections, and connections for hoisting — should be securely timbered.

In view of the local conditions, the following method of timbering appears the most satisfactor}. After the hole is sunk to the required depth by thawing, a square set with 6-foot centers — or should the shaft be 4 by 6 feet, of this dimension — is put in at the bottom. Threeinch pole lagging, with cross sets of 0-inch timbers inside at 6-foot intervals, is carried up to the collar. Inside the sets 6- or 12-foot poles, 3-inch, are nailed in the four corners to the cross sets. Moss is laid up outside the pole lagging, as dry as possible, and packed against the gravel or muck walls. In cases where it is impossible to sink without timbering as the shaft is sunk the timbering is carried down, and the lagging is driven as each set progresses, the square set being put in at the bottom on the completion of the shaft. Shafts timbered ia this manner have been found to stand for periods of from one to two years, as long as the work in the Fairbanks district has been in progress, and there is no reason why they should not stand much longer.! Timbering of this sort can be done for the most part with the ordinary cord wood delivered for fuel, and this is much the cheapest method available.

The cribbing method is sometimes adopted, accompanied by the same packing, with moss outside the cribbing. It is, however, more expensive, and in a shaft of considerable depth is much more likely to get out of plumb in this frost-ridden country.

pukington.] HYDRAULIC MINING. 99

In the Fairbanks district it has not yet been found necessary to timber the underground workings to any great extent. The main runway, if it is to be used for the whole season or for a period exceeding a month, should be timbered for safety. Six-foot sets of posts and caps only, with lagging over the roof, are generally sufficient. Pole lagging is cheaper and more advisable than split lagging. The caving system, working always toward the shaft, allows the faces to be carried forward without timbering of the stopes. The elaborate timbering methods necessary in the Klondike benches and in many parts of California in drifting operations are happily not needed in this portion of Alaska, and are not likely to be required in any extension of the Tanana area. No case has been seen in the operations, as thus far developed, where false sets were carried in taking out the gravel. When the operations at Fairbanks become more extensive, however, and drifting is carried on more systematically with wide faces, it is very likely that the workings will require timbering. At present it is not possible to give the cost of this work, as the figures were not obtainable.

Hydraulic Mining.

General Remarks.

The hydraulic method of working gold gravel deposits is the most economical method from the standpoints of power, capacity, and labor. It is, on the other hand, exceedingly wasteful of water, and the topographic conditions under which it may be successfully and profitably onductedarenot of common occurrence, even in mountainous districts.' The hydraulic method of mining was invented by Edward E. Matteon, a native of Sterling, Conn., and applied by him to the auriferous ravels in California in 1852. b One or more jets of water under respire are thrown from a pipe or pipes with great velocity against he face of a gravel bank, and the gravel is loosened by the stream so hat it falls or "caves." The gravel is struck with sufficient force to disintegrated and broken up so that it can be carried by the current nto the sluice if the bed rock has a sufficient grade. For assistance in aoving and washing the gravel after it leaves the bank, additional

The amount of water used in hydraulicking is shown by the following illustration: Three hunred million gallons of water a day are used at present for the supply of Greater New York City, or 5,666 miner's inches, of twenty-four-hour service. Taking the duty of an inch at 2 cubic yards, and tenor of 15 cents in gold per cubic yard, the above amount would supply only 13 hydraulic mines, tch using 2,000 miner's inches under head. The total amount of gravel washed would be 52,000 ibie yards per day, and the product $7,800; or (with a season of one hundred and twenty days) inually, 6,210,000 cubic yards, and a product of $936,000, an amount not startlingly large, consider g the magnitude of the operations involved.

lit is to be expected that persons with a limited knowledge of hydraulic mining will object to the w capacity and short season assumed in the above, bul operators of long experience will realize at the conditions and results are assumed, if anything, more favorable than is found in average lactice. Whitney, J. D., The auriferous gravels of the Sierra Nevada of California: Mem. Mus. Comp. Lol. Harvard Coll., vol. 6, 1SS0.

100 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

water is frequently used under slight head, and is known as ""bank head" or " by-wash" water. Various devices for more easily disintegrating the bank and for disposal of the large bowlders and of tailings where natural grade is lacking will be later discussed.

In California the application of hydraulic mining spread with great rapidity, especially within the drainage basins of San Joaquin and Sacramento rivers. This method was adopted also in other portions of the western United States and in other parts of the world, particularly in Australia and New Zealand. In the part of California referred to, extensive operations ceased, not because the gravel deposits were exhausted, but because of economic considerations other than those of] mining. The passage of an act of Congress in March, 1893, entitled "An act to create the California Debris Commission and regulate lrydraulic mining in the State of California," sounded the death knell of the huge mining operations which had changed the topography and blanketed many square miles of arable lands in the San Joaquin and Sacramento valleys with gravel tailings.

The comments of J. D. Whitney, a written in 1880, concerning the application of hydraulic mining to California conditions, are as fellows:

It is owing to a happy combination of favorable circumstances that the system of hydraulic mining has been so successful on the slopes of the Sierra Nevada. That the peculiar set of conditions which makes hydraulic mining possible is not often . met with is sufficiently proved by the fact that this system, which seems so admirably adapted to the needs of the Californian gravel miners, has hardly been at all successful in any other region. It has been tried again and again in the southern United States with almost unvarying loss; and even in Australia, where the mode oq occurrence of the gold is in many respects so similar to what it is in California, thereS are few districts where the hydraulic method can be applied.

The first great need of the hydraulic miner is an abundance of water and with a considerable "head," so that the stream may issue with sufficient velocity from the pipes.

An abundance of water can not be secured without extensive engineering operations and the expenditure of a large amount of money. Extensive reservoirs must be constructed by building dams across the outlets of the mountain valleys, so as to impound the water coming from the melting of the winter's snow on the high Sierra, and the necessary canals — or ditches, as they are universally called by the miners — must be excavated to carry the water to the points where it is needed for use. The long, rapid, and rather uniform slope of the Sierra, in the mining districts, makes it possible almost everywhere to carry the ditches with such a grade and in such a position as to allow the water to be taken from them at a sufficient elevation to give the necessary head at the point of working. The great elevation of the important gravel masses and the deep canyons into which the whole mining region is cut up, afford, in almost every locality, the necessary facilities for arranging the sluices and disposing of the tailings.

A need equally as great, not sufficiently emphasized by Whitney, is adequate grade or slope of the bed rock for the moving of material. Experience has shown that the lightest grade of stream bed upon

aLoc. cit., p. 62.

i?ukington.] HYDRAULIC MINING. 101

which hydraulic operations may safely be undertaken is 220 feet to the mile.

The above statements regarding hydraulic mining are as worthy of consideration to-day as when they were written. Bench deposits, as already defined, are those above all others to which the hydraulic method is most likely to be successfully applied, because adequate grade for the disposal of tailings can be secured. Deposits in the beds of present streams, on the other hand, are exploitable by hydraulicking to a far less extent. In Alaska extensive bench deposits do not occur, even in the alpine districts of the south coast, and, moreover, where auriferous benches are found they are not backed by high mountains from which the water under pressure can be obtained. The bench deposits of Alaska are not characterized by great thickness as are those of California. A depth of 10 feet of auriferous gravel with 20 feet of overlying barren silt, or a total of 30 feet, is a not uncommon condition in Alaska, while in California gravel banks of 75 to 500 feet in thickness occur and have been worked by hydraulicking. The hydraulic operation shown in PI. XV, B (p. 92), is on a lake bed, locally formed in a portion of Silver Bow basin, Juneau district.

The hydraulic principle implies the breaking down of all the alluvial material by water under pressure, the cheapest power. It is evident that unless the gold is distributed throughout the vertical section of the alluvial deposit, as well as on and in the bed rock, the greatest amount of material is hydraulicked off at a loss. In general the dirt in Alaska composes less than 15 per cent of the bank, measured vertically. In California gravels, on the other hand, much more frequently a small amount of gold occurs throughout the whole bank.

In Alaska attempts have been made to work very shallow ground, in some cases of 5 feet section, by hydraulic methods involving the construction of ditches and installation of machinery at a cost of $100,000 and over. Unless the gravels worked were much richer than previous workings in the vicinity, it was impossible to see how the enterprise could by any means be profitable. Simple mechanical plants, requiring a comparatively small investment, could have handled the small body of gravel fully as fast and in the long run more cheaply. It is undoubtedly true that many men are deterred from installing really economical plants of a mechanical nature by the desire to apply the spectacular methods of the hydraulic miner, without regard to the existing conditions.

A word should be said about the application of power to produce pressure for hydraulicking." Several plants where this principle is applied have been visited in Alaska and the neighboring British territory. Nine plants were seen and it was not clear that any plant pump-

a These statements do not refer to the hot- water method of hydraulicking frozen gravel.

102 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

ing water for hydraulic mining was making expenses. Some Nome operators are of the opinion that if crude oil can be obtained for $2 a barrel the gas engine can be profitably used to hydraulic certain rich patches of the coastal plain gravels, using 50 to 60 pounds pressure at the nozzle. Only under the most exceptional conditions would such an application of the hydraulic method be profitable. It may be truly said that 95 per cent of all attempts to pump water in hydraulic gravel mining, in whatever portion of the world they have been tried, have been failures. The miner who contemplates such an operation in a remote region where coal costs $30 a ton or wood $15 a cord had better first exhaust the possibilities of all other methods of moving gravel which circumstances or ingenuity can suggest.

It must not be assumed that the tenor of the gravel in Alaska is greatly above that of the auriferous gravels formerly worked so extensively in California, especially where it is necessary, as in hydraulicking, to distribute the value contained in the thin-bottom pay streak throughout the whole of the vertical section of gravel which must be moved. a There is a widespread opinion, amounting to a dictum, that the hydraulic method should be installed in preference to others wherever there is the slightest chance for its success. That this chance is small in the hitherto developed portions of Alaska the present account will make clear. Capital invested by the miner in expensive water conduits in Alaska is not recoverable except from the profit on his operations. The ditch builder can not enter the domain of commerce and sell his water or the power generated thereby, as do many of the water companies in populous agricultural and industrial communities. In rare instances only can he even sell it to miners. On the exhaustion of his own auriferous ground, his ditch and plant becomes practically valueless.

While hydraulicking river and creek beds in Alaska with the necessary accompaniment of some form of lifting operation for the tailing! is not to be entirely decried, it should be undertaken with extreme caution. The ever-present danger of floods and the expense of wing dams must be considered. The tailings will be raised by the water lift primarily, and the method of using this in gravel mining will be fully described. The operator should bear in mind, however, that the introduction of the water lift decreases by over CO per cent the duty of the unmodified hydraulic method as above described; also that the

"For example, Whitney states (loe. cit., p. 118) that the area hydraulicked off at Todds Valley, Placer County, Cal., was 1 mile by one-fourth mile in area, and the gravel from 35 to 75 feet in thickness, a total of nearly 9,000,000 yards, with an estimated yield of $4,000,000, or about 44 cents per cubic yard.

At the Excelsior claim, near Placerville, Eldorado County, Cal., 20 acres of ground were washed off with an average thickness of from 40 to 60 feet of pay gravel. The yield was estimated at $5,000,000, about half of which was taken out by drifting and the other half by hydraulicking. Mr. Alderson, the principal proprietor, estimated that the yield of the Excelsor gravel was per cubic yard. A single placer claim of 20 acres, containing so large an amount of gold as the Excelsior claim, has yet to be discovered in Alaska.

p.iuN.rroN.] HYDRAULIC MINTNU. 103

use of the ingenious device entails a new set of difficulties with which his previous experience in hydraulic mining will hardly have fitted him to deal. An unfortunate instance was seen in one of the remote districts of Alaska, where a hydraulic elevator of 5 tons weight had been imported at a cost of nearly $2,000 and was found useless because insufficient water to operate it was obtainable, although a ditch and flume line had been constructed at a cost of $15,000. The elevator lay on the bank, and a makeshift had been improvised from a piece of sheet-steel pipe and a fireman's brass nozzle.

That hydraulic operations are and have been successfully prosecuted in Alaska is not to be denied. The cautionary remarks which have been made will serve as a reminder, however, that the moving of large bodies of gravel by water under natural head is not always as cheaply accomplished as a casual inspection of such operations would induce one to believe. In any event, a hydraulic installation, under conditions where the cost of leading water runs into the thousands of dollars per mile, should not be undertaken until due consideration as to the possibility of using other methods has been given.

Ditches, Flumes, And Reservoirs

In table 8 an attempt has been made to show in concise form the principal facts regarding the construction of water conduits in Alaska and the North. So great was the extent of territory covered that opportune for measurements and calculations was only occasional. The statements of operators were generally accepted; they were rejected only when they were palpably misleading. When not otherwise indicated, the data shown were supplied by the operators. When the data Avere based on subsequent estimates, the figures are starred.

It can not be too strongly stated that the tables in this report are based on statements of operators and are not the result of detailed investigation of properties. The collection of data for this report necessitated the covering of a vast extent of territory in four months1 time. The data are as complete and as nearly accurate as the circumstances allowed. Estimates based on the cost of water conduits as given below, and the amount of water available, should take into consideration the degree of authority which attached to the compilation.

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Long conduits are used in order that the difference in elevation between the source of the water and the point where it is used may afford the pressure. The length of the conduit will depend on the slope or grade of the surface. In regions of low mountains and gentle slopes, long ditches or flume lines are necessary. In steep mountain regions the same results are attainable with short conduits.

In the gravel-mining districts of Alaska examples of the two extremes are found. It is an unfortunate, but at the same time natural, result of the governing geological conditions, that to obtain the use of water under head ditches must be the largest in the richest and most promising placer districts of Alaska. A long head ditch is expensive both to construct and to maintain. That the expense of such undertakings has not deterred miners from attempting them is evidenced by early California operators, where single companies sometimes built more than 100 miles of ditch line. Each mile of ditch line or other form of conduit adds from $2,000 to $15,000 to the initial capital necessary to start the hydraulicking operation, and increases the annual cost of ditch maintenance.

Some of the precautions which apply equally well to an}r country regarding the construction of water conduits, found in the text-books on hydraulic mining, may well be repeated here.

Van Wagenen" says:

When the miner has measured the stream from which he is to draw his water supply, and has determined the point where he will tap it, he is prepared to conrider the question of water channels. These may be of three kinds — the ditch, the wooden flume, and the iron pipe. It is generally desirable to have the east possible fall in a water channel, or, in other words, to bring the water to as high i point of the ground to be worked as circumstances will allow. As the friction of ;he sides and bottom of a channel retards the flow, and necessitates a higher grade ;han would be necessary if there were none, it becomes of importance to decrease his element as much as possible. On this score wood and iron waterways present lecided advantages, owing to their comparative smoothness. In any case, however, the quantity of friction developed depends upon the wet perimeter of the hannel used. The following law will therefore be found to be of service:

The least wet perimeter that will hold or carry a given volume is attained when the width f bottom is from one arid three-fourths to two and. one-fourth times the depth of the sides.

For example, a channel having a cross section of 510 square inches will develop the >ast amount of friction when its dimensions are 15 by 34 or 17 by 30, or somewhere x'tween these measurements. A knowledge of this fact will be found serviceable in instructing flumes. The least perimeter, of course, requires the least lumber, and nan v thousand or million feet may be saved in a long flume by building in the cored proportions.

I Bowie6 says:

All water courses on the line of the ditch should be secured. Their supply pariallv counteracts the loss by evaporation, leakage, and absorption, and frequently prnishes an additional quantum of water during several months of the year.

a Van aenen, T. F., Manual of Hydraulic Mining, 1880, p. 51.

Bowie, A. J., jr., A Practical Treatise on Hydraulic Mining in California, 1885, p. 135.

112 GRAVEL AND PLACER MINING IN ALASKA. [bull. 268.

At proper intervals waste gates should be arranged, so as to discharge the water when necessary without risk of damage to the ditch. In regions of heavy snowl these wasteways should be provided at intervals not greater than one-half mild Ditches poorly built in the beginning subsequently require large and constant expenditure, and lose considerable amounts of water

George H. Evans a says:

At the different points along the line of race where fluming has to be resorted to, allowance should be made for an increase in grade, in order that the flume can be constructed of much smaller dimensions than the ditch and yet carry all the water required. It will be well to remember that practical results have demon-

strated that in ordinary ground the water should travel at the rate of from 180 to 200 feet per minute. Then the grade will.be determined by the dimensions of the ditch and its intended carrying capacity.

The above quotations may be considered as of genera) application, but many modifications in the hitherto accepted practice of ditch building have been found advisable in Alaska, and will be referred to, especially in the description of the practice in Seward Peninsula. Regarding the capacity of open conduits, Bowie makes the following statement:

In the mining districts of California ditches are constructed badly, with steep grades and on irregular lines with numerous sharp curves. The cross sections, originally uniform, became more or less varied. Absorption, percolation, evaporation, and leakage reduce the flow. A distinct, reliable factor for each of the sources of loss can not well be incorporated in the coefficient of discharge. The simple formula Q=ac\/rs expresses more fitly the result of experience in such cases wherein:

Q is the quantity of water which the ditch is capable of carrying in cubic feet per second.

a, the effective area of cross section of ditch, as originally constructed, in square feet.

r, the hydraulic mean depth in feet.

s, the fall of surface in a unity of length.

c, a coefficient covering all common losses.

Statistics derived from experience on the Milton, La Granger, and Bloomfield ditches in California led to the adoption of values of the coefficient c varying from 31 to 45, in estimating the capacity of ditches in heavy grades of 40 miles' length flowing from 60 to 80 cubic feet per second.

The Texas Creek branch ditch (of the North Bloomfield ditch) is about seventenths of a mile long. Its sectional area is 13.5 feet and the grade is 20 feet per mile. The sides are rough and the curves sharp. With a flow of 32.8 cubic feet per second, the ditch runs about full. The value of c=33. In connection with this ditch there is a rectangular flume 2.67 feet wide by 2.83 feet deep, made of unplaned boards, set on a grade of 32 feet per mile. The flume has some sharp but regular curves, and the water from the ditch runs nearly full at these points. With the discharge 32.8 cubic feet per second, c=59.

Although the losses in leading water in Alaska have not been determined by exact experiments, it is likely that they are less than in California. In the interior the value of c for ditches would be slightly

a Evans, G. H., Practical Notes on Hydraulic Mining, San Francisco, 1898.

Hydraulic Mining.

higher than in California, while in the ditches made on gentle slopes I Seward Peninsula c would be considerably higher. Its value can lot be known until accurate experiments have been conducted on the arious ditch lines.

Examples of the discharge of ditches in California, given by Bowie, re as follows:"

Locality.

Grade.

Size.

Discharge.

iorth JBloomfield . . . )utch Flat

Miles.

1(> feet per mile

13J feet per mile

7 to 8 feet per mile.

8.65 feet top by 5

feet bottom by

feet deep. feet top by 4 feet

deep. 9 feet top by 6 feet

bottom by 4 feet

deep.

Miner's inches. 3,200

3, 150

,a G range

2,400

In considering ditches and ditch building, the three provinces of laska, namely, the South Coast, Interior, and Seward Peninsula, will e taken up in succession.

South Coast Province.

In the South Coast province of Alaska the topography permits a

ipid increase of head in short distances. (See PI. XVI, A, p. 114.)

le ditch line of the Alaska-Treadwell Gold Mining Company, 14 miles

length, delivers water from the penstocks above the mill — to which

supplies power— at an elevation of 480 feet. As may be seen from

le map (fig. 19), the ditch heads in Fish Creek 1,000 feet above the sea.

he water at the upper penstock, midway on the ditch between Doug-

s and Treadwell, is taken out at an elevation of 600 feet above the

. The distance from the penstock to the nozzle is only 1,500 feet

slope, and it may easily be seen what advantage is gained from the

eep topography. The grade of the mountain, nearly 30 feet in 100,.

such that were a sufficient amount of water available in one of the

sar-by creeks no ditch at all would be required. The water could be

$d out by a few hundred feet of flume to a penstock, and a pipe line

Id directly from this to the mill. The Treadwell ditch line is com-

Iksite, so far as its contained water is concerned, since it taps suc-

ssively Fish, Eagle, Cowee, Lawson, Paris, Bullion, and Ready

J illion creeks. Its length is not extreme considering the amount of

Uter obtained, but it is considerably greater than would have been

ijcessary if all the wrater could have been obtained from a single creek

c river.

"Bowie, op. cit., p. 139.

Bull. 263—05-

Gravel And Placer Mining In Alaska.

[bull.

The apparent extraordinary fall of the Tread well ditch (over 20 ft to the mile) may be accounted for by the fact that it has, at each ere which it taps in its course, a drop off of 6 to 7 feet, and reservoir, which are relief gates, as illustrated in the photograph of the ditch Lawson Creek. (See PL XVI, B.) One of the waste gates sho on PI. XVI, B, is 5 feet 4 inches wide; the other is 6 feet 7 inct wide and 3 feet 3 inches deep. There is a smaller auxiliary gs 4 feet 6 inches wide and 2 feet deep.

The Treadwell main ditch is 14 miles in length, and is supplement by 4 miles of subsidiary ditches/' The main ditch heads in Fi Creek, and its supply of water is obtained successively from Eag Cowee, Lawson, and Paris creeks, while an additional ditch brings wat

Fig. 19.— Map of portion of Juneau district.

Is Us

from Ready Bullion and Bullion creeks. In summer the water for running 760 of the 880 stamps of the mills, but in winter it is r used for power purposes.6

The main ditch has a width of 7 feet on top and 6 feet on the torn, and a depth of 5 feet. In 1904 construction was going on portions of the ditch line as follows: Twelve-inch posts, in sets wi* 5-foot centers, were being placed along the inside of the ditch, leavi space 5 feet in the clear at bottom and feet in the clear at top, wi* 7-inch cap logs 4J feet between shoulders. Lagging split 3 inct thick and 1£ feet wide was laid inside the posts. Moss and sod w€

"See Kinzie, R. A , The Treadwell group of mines, Douglas Island, Alaska: Trans. Am. Inst. IV: Eng., vol. 34, 1901, p. 374. ''It is to be regretted that full data regarding the Treadwell ditch are not at hand.

U. S. Geological Survey

Bulletin No. 263 Pl. Xvi

A.. Topography, South Coast Province.

B. Treadwell Ditch Line At Lawson Creek, Douglas Island.

purington.] HYDRAULIC MINING. 115

then tilled in between the lagging and the side of the ditch, poles laid lengthwise over the caps, and sod laid over i\w whole. Fluming has been found very unsatisfactory at the Treadwell. The flume was banked with sod on sides and top. Anchor ice in winter collected in the bottom of the flume, and was removed with great difficulty.

The Treadwell ditch for long distances is bridged with poles and brush, which in many places are covered with sods. Sodding is said to be the besk preventive against freezing, not only here, but in all parts of Alaska.

The pressure boxes are connected with the ditch by flumes 35 feet long, 5 feet wide, and 3 feet deep. The water first enters a gravel tank which is cleaned twice a year. This tank is built of 2-inch lumber and is 8 feet wide by 9 feet long and 14 feet deep. From the tank the water flows through a 4-foot section of flume 3 feet 3 inches wide, the bottom of which is only 5 feet below the top of the tank, into the main penstock. This is 11 feet long by 9i feet wide, inside measurement, and 14 feet deep. It is built of 3-inch lumber, with 8- by 10-inch posts, sills, and caps, with 4-foot centers. The penstock is fitted with a wooden inclined grizzly to catch any leaves or refuse that pass the ."ravel trap. The penstock and sand trap combined make a structure >A) feet 6 inches long by 10 feet 10 inches wide by 14 feet deep, outside measurement. The penstock, as illustrated in PL XVII, A, is ranked halfway up the sides with sod, and the pipe line leading from t is covered with sod. The sand trap is provided with a sluicing-out rate on the side opposite that shown by the photograph. a

PL XVII, B, illustrates a method of guying the pressure box on teep slope, in use by the American Gold Mining Company in Silver 3owr basin, Alaska. The intake of the pipe line is protected by shed rom heavy snows.

As water is in use for placer mining only during the open season, ew instances were seen in Alaska of attempts to sod up the ditches nd connections to prevent freezing in winter. At the Treadwell, owever, the water is used for generating power. Pipe lines, specially in Seward Peninsula, are frequently sodded over, as much or protection against rust as to prevent freezing. In Silver Bow basin, east of Juneau, ditching has been found impraccable and all conduits are flumed. In general in southeastern Alaska using will be found cheaper than ditching, as ditches would have to e cut in solid rock for the most part, and in numerous places the lountain slopes are so steep as to render their construction impossible.

a See Bowie, A. J., jr., A Practical Treatise on Hydraulic Mining in California, 1885, p. 177, for plan id elevation of North Bloomfield pressure box.

116 GRAVEL AND PLACER MINING IN ALASKA. [bull .263.

The flume of the Jualpa Company," one- half mile northeast of Juneau, is shown on PL XV1I1, A. The water is taken from Gold Creek, the head gate being 9 by 8 feet. The flume is 4,600 feet in length, and has a grade of inches in 16 feet, or 34.3 feet to the mile. It is 4 feet 8 inches square, inside measure; the bottom and side boards are 2 inches thick, planed inside, and battened with 3- by -inch lumber; there are 4 collars to a box of 12 feet; each alternate collar consisting of a 5- by 5-inch sill, 8 feet long; two posts 4 by 6 inches by feet high, with a gain of one-half inch into sill, and two caps of 2- by 4-inch pieces nailed to the sides of the posts above the cover boards. The yokes are braced with 2 by 12's. These collars have 6-foot centers, and alternately between them are }>okes consisting of a 3- by 5-inch sill, and two 4- by 4-inch posts, uncapped. The flume is covered with boards by 12 inches by 5 feet, laid crosswise, and nailed. Each box contains approximately 425 board feet of lumber. The cost of the flume is said to have been $2.20 per foot, or $11,616 per mile, including lumber and labor. This did not include the cost of shooting rock for the flumeway, which was as high as $5 per foot in places. A head of 225 feet is obtained, and the capacity of the flume is said to be 5,000 miner's inches.

The pressure box to which the flume leads is 12 by is feet by 11 feet deep. It is built of 1-inch lumber, and has collars of 8- by 8-inch timber. The pipe at the intake end is 36 inches in diameter.

In building flumes about Juneau wrestling frequently has to be resorted to, thus adding greatly to the expense. In general it may be said that the cost of building a 4-foot flume in the So <th Coast province will not fall greatly below $10,000 per mile, and will occasionally be double this amount.

For small flumes, Bowie gives the following specifications:

Specifications for flu in r feet wide, feet deep; 12-foot box.

Feet.

3 caps, 4 feet by 3 by 4 inches 12j

6 posts, 3 feet by 3 by 4 inches 18

9 planks, 12 feet by by 6 and 12 inches 135

3 sills, 4i feet by 4 by 4 inches 18

2 stringers, 12 feet by 4 by 6 inches 48

6 battens, 12 feet by 3 inches by 1 inch 14

1-foot plank, 12 feet by 10 by inches 15

Total lumber in one box 264

Number of boxes per mile, 440.

a Recent information (Mining and Scientific Press, December 31, 1904), states that elaborate preparations for operating this property were made the last summer. These include the interception of the water of Gold Creek above the property by a dam, and its diversion to a flume to carry it past the hydraulic pit. The flume is 20 feet wide by 9 feet deep, and 4,250 feet long, 2,250 feet being trestled. It contains 1,200,000 feet of lumber, 6,000 linear feet of hewed timber, and 20 tons of nails and .bolts.

&Op. cit., p. 149.

U. S. Geological Sure

Bulletin No. 263 Pl.

A. Pressure Box In Treadwell Ditch.

B. Method Of Staying-Pressure Box, Silver Bow Basin.

HimiNirroN.] HYDRAULIC MINING. 11?

Reckoning the cost of lumber for a box at $4 and the labor of 1 man at $5 for one day to each box, such a flume would cost $4,000 per mile, exclusive of survey, rock work, and trestles. Jt is difficult to see how the cost of building even small flumes can fall below $7,000 per mile in the South Coast province of Alaska.

Interior.

In the interior Yukon and Tanana fields ditching is practicable and Is recommended in preference to mimes. There are difficulties, but they are not insurmountable. In the interior no large ditch enterprise similar to those of Seward Peninsula has been undertaken. The Atlin field has afforded data regarding building of ditches, but conditions are hardly comparable with those in the Yukon region. With the exception of the small amount of bench mining in the interior only a small amount of gravel is handled daily, and ordinarily water under very low heads is used.

The future of hydraulic mining in the Klondike, Birch Creek, Fortymile, Eagle, and Tanana mining districts is not promising. The gentle slopes of the mountains, the low grade of the creek valleys, and the sparse amount of water are unfavorable to obtaining a sufficient amount of water for hydraulicking at a working head. A peculiar drawback, depending on the geological history of the region, is the fact that the level tops of the Yukon and Tanana mountains represent a partially eroded peneplain of very wide extent — 300 miles from east to west and from north to south, approximate. This area, in which the placer fields of the Y'ukon-Tanana rectangle are situated, is, as it wrere, a table-land, the top of which tilts slightly to the south, and into which the modern streams have cut, rounding off the residual parts between them into low dome-shaped mountains, averaging 3,000 feet in height, and varying from 6,000 to 2,000 feet.

A comparison of the topography of the South Coast province with

|:hat of the interior is illustrated by Pis. XVIII, B, and XIX, A. In

the interior there are no sharp declivities, no waterfalls, no sudden

descents in the surface. The grades of creek valleys are seldom er

B feet in KM) and are commonly 1 foot in 100. (See table 8, p. 104.)

If 2 per cent is taken as an average grade and it is assumed that a ditch

must be three times as long as the creek on which it is to furnish

vater under head at a lower point, it is evident that only 300 feet

iiead would be obtained by 10 miles of ditch. Such a ditch taken

'rom one stream would afford only 200 miner's inches of water, a fair

iverage for the region during the four months of the summer season.

WitJiin leading distance there are no high mountains from which to

lrawT a supply. The alpine peaks of the Alaska Range lie to the south

the Tanana, and could not by any possibility be made to afford

yater to be used for hydraulicking. (See PI. XLI, B.)

118 GRAVEL AND PLACER MLN1NG IN ALASKA. [bull. 263

Ditches and flumes for conveying- water must, as hitherto, be of small size. They will deliver a small amount of water at a low head. J 00 miner's inches of water at 75-foot head being about what may be obtained under favorable conditions.

Special difficulties encountered in the interior of Alaska and the North generally have been found to be as follows:

At Atlin the action of frost causes the ditch to enlarge after construction. The opinion was expressed that steel-pipe conduits do not freeze as quickly as flumes. In a 19- by 40-inch flume of L,960 feet in length it was found that the frost heaved the flume and put it out of grade each season, but even then it was regarded as more economical than a ditch. The flumes on McKee Creek have to be gone over every spring to restore the grade. Sills are set in 4 inches of blocking on the stringers so that the grade can be regulated. It was also said that the native Atlin lumber is preferred for the flumes and sluices, as imported Pacific coast lumber warped badly. If native lumber is used, 8 inches is the greatest width available. Notwithstanding the cost of maintenance, ditches are much used at Atlin, one company operating 10 miles of ditch.

In the Klondike district, where nearly all ground is solidly and permanently frozen, it is said that three years after construction must be allowed to get a ditch into condition to stand. Various estimates have been made and projects formulated in this field for bringing in water from a distance for the purpose of working the remaining gravels of the benches (the so-called ''White Channel") which lie at an average elevation of 270 feet above the rich bottoms of Bonanza, Eldorado, and Hunker creeks. The building and maintenance of a ditch having its source in some of the higher tributaries of Klondike River and affording water at a sufficient head is not regarded as an impossible engineering feat, but up to the present the cost has been considered prohibitive. Dry seasons alternate with wet ones, and in consequence the amount of water available during a given season might vary from, say, 1,000 inches to 5,000 inches. No calculations based on the full capacity of the ditch could be made in advance, therefore, regarding the season's product.

Recent information concerning the Acklen ditch, led along the north side of Klondike River near Dawson for the purpose of hydraulieking high benches bordering that stream, has been embodied in the table. It is stated that the cost of the earth excavation of this ditch, 7 by 4 by 2i feet deep and 41,500 feet in length, was $34,000.

Small storage reservoirs are used by many of the Klondike operators to impound the small and variable amount of water available for working the benches of the White Channel. On Hunker Creek a small ditch 3 by 2 feet and 4 miles long is in excellent condition after

U. S. Geological Surven

Bulletin No. 263 Pl.

Flume Of Jualpa Mining Company, Silver Bow Basin.

11. Typical South Coast Topography, Gold Creek.

ptJBiNGTON.] HYDRAULIC MINING. 119

four years' service. The annual cost of maintenance is $1,000, or per cent of the original cost.

In ditching in bad ground it has been found beneficial not to remove the moss carpet, but to cut it in 4-foot lengths, transverse to the line of ditch, then to roll it back along the lower edge, and after the ditch is dug to let it drop so as to cover the side of the ditch.

In the region adjacent to Eagle, Alaska, it has been found that where the topography did not admit of ditching the maintenance of Humes is very expensive and that the use of steel-pipe conduits is preferable.

A useful suggestion for flume building was obtained on Deadwood Creek, in the Birch Creek district. Flat timbers obtained in the neighborhood were used, and the flume, 3 feet by 1 foot, was calked with moss inside. The cost was only 25 cents a foot, and the flume is said to be good for ten years. In this locality it is almost impossible to secure sawed lumber at any price unless the operators whipsaw it themselves. In all northern latitudes the moss is an excellent calking material.

Through the interior country it has been found that ditches on the south slopes of the mountains can be made with much more success than on the north slopes. In fact, the north slopes are frequently bare rock, while on the south slopes a good deposit of earth has accumulated.

The presence of crystosphenes, a which are found on the slopes as well as in the creek valleys in all parts of the north where perpetual frost prevails, is the ditch maker's greatest obstacle. Mr. Tyrrell sajs: As a rule they [the crystosphenes, or so-called 'glaciers'] occur as more or less horizontal sheets of clear ice, from 6 inches to 3 feet in thickness, lying between layers of 'muck' or fine alluvium, usually where the cmuck' is divided horizontally by a thin bed of silt or sand; and most of them, as far as my observation goes, are from 2 to 1 feet below the surface, though some are deeper. They approximate closely Ito the slope of the surface, under which they lie." These sheets are from 25 to 150 feet in diameter, generally somewhat oblong. They arc explained by Mr. Tyrrell as due to the freezing of seepage water, pausing a gradual accretion to the mass annually. Mr. J. P. Tolmachof6 has examined similar occurrences in northeast Siberia, and explains them as fossil snowbanks. Whatever their explanation, they ire exceedingly common both in the interior and in Seward Peninsula. They are found not only in creek beds, but on the slopes, and show no regularity in distribution.

Tyrrell, J. B., Crystosphenes, buried sheets of ice, in the tundra of northern America: Jour. }eol., vol. 12, 1904. ''Ground ice of Berezovka River: Proc. K. Russ. Min. Soc., St. Petersburg, 1903.

120 GRAVEL AND PLACER MINING IN ALASKA. [bull. 26*

Where such a mass of ice is met sod and moss must be extensively used, and both the first construction and annual maintenance will be much greater than in other portions of the ditch. For an account of the method of dealing with such ice sheets see the description of ditch building in Seward Peninsula.

In the Fairbanks district so little ditching has been done that no results gained from experience were available. The frozen ground has, however, been found so bad for ditching that the cost of annual maintenance is from one-fourth to one-half as much as the first cost of construction. Such expedients as patching with canvas have been adopted as a temporary makeshift. The small ditches which have been constructed are run with as flat a grade as possible to avoid cutting out. Here as elsewhere in the interior the use of sod for lining the sides of the ditches can not be too highly recommended.

Small reservoirs in the creek beds for impounding sluice water are in use and will be described in connection with open-cut mining.

Seward Peninsula.

The following notes regarding the building of ditches have been contributed by Mr. Guy A. R. Lewington, of Nome, Alaska, manager of the mining properties belonging to the North American Transportation and Trading Company:

Ditch building in Seward Peninsula has become one of the most serious questions with reference to economical mining and the general stability of the whole mining industry. Water under pressure for hydraulic mining is the all-important condition, and to this end I submit the following, which may be of some interest to> those contemplating investment in this section.

The necessary equipment consists of plows, scrapers, and graders of the usual kind in use in the States, and, of course, a camp outfit of tents, both for living and stable purposes.

The conditions to be contended with in this country are different in almost all respects from those which have come under my observation elsewhere. The most serious of these is the building of a tight and strong ditch over "glacier," of which much is encountered wherever ditches have been constructed. Under this condition it has been found best to dig as shallow and broad a ditch as possible, not digging much below the moss, and to build the outer bank of the ditch up to the required height by the use of the sod which covers the whole country. This sod in a short while settles and knits itself together, and thus becomes a very serviceable bank. It will not cut or wear out, and the older it gets the better it becomes. When, however, it becomes evident that the bottom of the ditch is cutting and wearing away, sod again must be resorted to, and by lining the bottom of the ditch with it the trouble may soon be overcome. In this way a ditch can be made over perpetually frozen ground where otherwise it would be impossible. Much ditch has to be constructed over loose stones with little or no sediment between them. In this case the ditch must be lined with sod and all holes must be filled by tamping sod into them as far as possible. This being done it will be found that the water traveling through the

a The buried ice sheets.

U. S. Geological Surve

Bui I Etin No. 263 Pl.

A. Typical Interior Topography, Mastodon Creek. Birch Creek District.

U. DiTCH BUILDING, HEAD OF NOME RIV

Peninsula.

Weington.] HYDRAULIC MINING. 121

ditch will deposit sediment over the sod and level it up, and that after a little while it will become tight. Puddling, of course, will help any ditch here or elsewhere. Those two conditions are the only serious ones to be contended with in ditching ground.

A strong plow drawn by 2-horse team is the first implement used. (See PI. XIX, B, p. 120.)

All being ready, the driver is instructed to plow a single furrow, following as closely as possible from one survey peg to the next, following the natural contour of the country. This he does for say a distance of one-half mile, thus establishing the ditch line. The plowing is continued to a width sufficient so that, allowing plenty of slope for the inner bank, the required depth of ditch may be obtained. The grader is next used for the purpose of removing what has been plowed to the outer bank of the ditch. This being done the ditch wTill look much like a wagon road. Then the plow is used again, plowing as before a single furrow, following as nearly as possible the first furrow plowed, which is plainly visible. This second plowing being done, the scraper is resorted to, and the loose plowed material is scraped from the ditch to the outer bank, building it up. This work is repeated until the ditch is almost completed. All that remains to make an excellent ditch is to level up the bottom and to slope the ditch to required dimensions. This work is done by hand with pick and shovel. The plow and scraper should do almost all the work, however, so that as little as possible remains to be done by hand. After completion of the ditch only a small head of water should be allowed to flow through it for a few days, until it has become well soaked; then the head may be gradually increased a ittle daily until the full capacity is reached.

All water should be turned out of the ditch before the freeze-up in the fall, and he ditch made as dry as possible by the opening of all waste gates, of which there hould be one at least every one-third of a mile. These waste gates should be left pen, to enable the water during the spring thaw to run out of them instead of filing the ditch with water and overflowing its banks. These waste gates should be learned of all snow and ice at the first approach of a thaw in the spring, in order that the water may have a free outlet. This is very important. In the spring no water should be allowed to run through the ditch until at least 2 to 3 inches in depth pf the ditch has thawed, and then only a small head to start with, as frozen ground 3iits very rapidly. If this work is carefully done I have no doubt that the ditch will be ready for work by the time it becomes possible to mine.

) Considering the remoteness of the country and its high latitude, ditch building ?an be done at a cost surprisingly low. The entire absence of timber, small amount pf rock work, generally good soil, and gentle slopes of the hillsides are conditions vhich make ditch building very feasible in the auriferous portions of Seward Peninsula.

; Fluming should not be employed unless absolutely unavoidable, as frost and snowin winter play havoc with flumes, and the swelling and contracting of the ground, lue to alternate freezing and thawing, continually keep the flume off grade. There ire few instances where it is necessary to use a flume.

Much of the ditch construction at Nome is now done by contract. The following information was supplied for this report by one of the litch contractors at Nome:

In the construction of ditches on Seward Peninsula the following hree types of machines are used, all being drawn by horses: The >rdinary road grader, the horse scrapers, which are so extensively ised in California, and an ordinary breaking plow.

122 GKAVEL AND PLACER MINING IN ALASKA. [bull. 2G3.

After the ditch line has been surveyed and staked 30 men and k20 horses, for example, with plows and scrapers, are put to work. The plows proceed ahead of the grader, and the cutting- is continued until the uphill side of the ditch bottom is nearly cut to grade. At this' stage, which is represented ideally by fig. 20, it will be seen that the contents of the cut A, B, C has been thrown up to form the bank C, D, E on the outer side of the proposed ditch. The remaining work consists in removing the earth in the portion B, F, H, which is partially uncut and partially built up by the grader. The most economical work is done when the portion removed by the grader is sol balanced as to demand the least cutting by the scrapers in throwing up the necessary bank. It will be seen from the above statements' that the burden of the work falls on the first plows and on the grader, though the subsequent work of the scrapers and hand finishing is just as important.

Four horses and 1 man are usually used to a grader, though 8 horses are often used. The scrapers use from 2 to 4 horses, depending upon

Fig. 20. — Section of ditch in construction.

the size of the ditch. Four horses are not generally used to a scraper unless the ditch is to be 7 feet or more wide. The plows breaking first ground usually need 4 horses each. It may be said that where a slope is steep very little or no cutting is needed on the lower side of the ditch, since the dirt necessary for the bank can all be obtained in reducing the upper side to grade.

Special methods are necessary when the ditch passes through sections underlain by ground ice, as previously described, or runs over sections of rock. Very careful work is needed when the rock is broken and fractured. It has been found bad practice to cut through the stringy moss which overlies the masses of ground ice, generally referred to as "glacier;" in fact it is disastrous to the permanency of that section of the ditch, and is the beginning of never-ending repairs, since the ice continues to thaw, causing constant leakage. The best practice is to build sod walls on the lower side, leaving the moss undisturbed. All rock work must be done by hand, and where the ditch

purington.] HYDEAULIC MINING. 123

passes through fractured material all cracks must be filled with moss. Too much care can not be observed in the latter detail, and, especially during the first weeks of use, men must be kept constantly traversing and repairing those sections where leaks are apt to occur. The stir ringup of the water by men walking along the bottom of the ditch is a good practice in the early stages, for silt, in addition to the sod, is a most valuable factor in filling the cracks.

A scraper will work to great advantage in decayed schist, which needs no lining, as it holds water better than any other ground encountered and cuts out less. Fluming does not pay when there is a possibility of ditch building. In fact, it has been often stated by men familiar with ditch construction, that where possible, it is profitable both as regards first cost and subsequent maintenance to build a ditch in place of fluming, even if the distance necessary to be covered by the former be ten times that of the latter. Many slopes apparently not permitting a ditch cut, owing to the presence of broken rock and talus slides, on close examination are found to be favorable, for if 2 or 3 feet of this loose material is moved there are excellent opportunities for comparatively cheap rock cuts.

When, however, it is deemed impracticable to construct a ditch, and where a flume must be built crossing a gully, a very efficient foundation can be made by digging shallow holes, filling with gravel, and placing on top a wide plank to distribute the load. If the trestle rests an such foundations, and the underlying ice is not disturbed, much trouble from settling will be avoided. The following are a few of the sosts representative of ditching in various materials:

Cost of ditch in g in nirious materials.

Soft muck and tundra, per cubic yard $0. 75

jrravelly dirt, per cubic yard .65

decayed schist, per cubic yard 40 to .60

3,ock work, fairly solid, per foot 1 . 75

Schist in place, per cubic yard 1 . 00

..oose rock, per cubic yard h 25

Ditching in muck which heaves is very expensive, and no general igure can be given.

A ditch carrying 1,000 miner's inches will cost, under fail' condiions, $2,000 per mile, One with the capacity of 4,000 miner's inches vill cost between $4,000 and $5,000 per mile. Though much affected varying local conditions a conservative estimate for general work s $1 per cubic yard throughout.

The following account of the construction of the extensive water onduits built by the Miocene Ditch Company was obtained from dr. J. W. Davidson, the company's consulting engineer.

The water is taken from Nome River and its tributaries for the most >art, although a small portion is taken from Snake River. At the

Gravel And Placer Mintng In Alaska.

[Bl'I.L. 2(.

intake near the head of Nome River the elevation is 572 feet." At

Hobson Creek a large head dam has been constructed entirely of sod. The dam was started at bed rock and is 20 feet in width by 130 feet in length and is provided with a waste gate 10 feet wide and 10 feet deep in the center. It has been found entirely satisfactory. The ditch, with its branches and laterals, is 54 miles in length. Of this, the main ditch is 31i miles from Hobson Creek to the tunnel. This ditch, as far as the "X," was made 10 feet on the bottom, 14 feet on top, with a depth of 3 feet. It has a grade of 3.37 feet to the mile. Seventeen miles of ditch were made from the head of Nome River to Hobson Creek, with the dimensions 8 feet wide on the bottom, 11 feet on the top, and 3 feet in depth, with a grade of 4. 5 feet to the mile. From the "X" to the tunnel, as represented on the map, the ditch has the same - dimensions as the upper end, and a grade of 0.5 feet to the mile. The ditch was constructed to carry 3,000 miner's inches of water below Hobson Creek, and at the upper end to carry 2,500 miner's inches. The actual amount of water available under average conditions is said to be 2,000 inches. The ditch was begun on July 6, 1901, at the "X." (See tig. The following year 75 horses and the necessary equipment—

1 . — Map of Miocene ditch.

21.)

a According to levels by U. S. Geol. Survey.

U. S. Geological Survey

Bulletin No. 263 Pl.

A. Miocene Ditch, Glacier Creek.

B. Flume Of Hot Air Company, Ophir Creek.

purington.] HYDRAULIC MINING. 125

plows, graders, and scrapers — were brought in and the ditch was completed to Hobson Creek. In 1903 the ditch was completed to the head of Nome River and a branch ditch was constructed to tap Snake River. Sixty-eight days were consumed in building the ditch from Hobson Creek to Dexter Creek, forty-eight days from Hobson Creek to Nome River. This latter figure includes the enlargement of the originally built Hobson ditch and the building of the Snake River ditch.

The method of construction has been described above. A plow was used for breaking the furrows and the grader was used for bringing the cut to grade, 1 horses being used to a team. The ditch making was carried on at the rate of one-half mile per day, taking the triangular section off down to a level. This operation was followed by a second plowing. The grade stakes were set at a certain distance down the hill from the lower bank, and the men were directed to push the dirt so as not to reach beyond the line of stakes. From 60 to 70 men were employed all the time, and the number of horses varied from 50 to 100. The cost was reckoned at $100 for each horse for a period of eight months, and the wage of a man was reckoned at $7.50 per day. Two 1-horse teams were employed all the time to haul feed. (See PL XX, A.)

The grading gang consisted of one 1-horse breaking plow and a grader, with 2 men and 8 horses. A scraping gang consisted of 2 plows and 9 scrapers. There are thus 11 drivers, 2 men plowing with 2-horse plows, 9 scraper men, and a foreman, beside the grader. The general cost of the smaller ditch is given at $2,300 per mile. It is to be noted that in this construction the upper bank was not sloped at all, as it was found that this sloping is very little use in the northern regions, the soil standing very well at various angles.

The difficulties with ground ice were very great. At one place 800 feet of such an ice sheet was found, and here the cost of maintenance is exceedingly high. The only way to maintain the ditch is to haul clay down the ditch in boats and dump it in. It is found that if sufficient clay is dumped on top of the ice it stops thawing, but this operation has to be annually repeated. At another point 1,100 feet of flume (8 feet by 33 inches, with double grade) were built over an ice sheet, and so far the ground has settled very little. One and one-half inch lumber is used in construction, at a cost of $200 per thousand feet. For each mud sill cuts were made into the ice from 2£ to 3 feet. After the sills were in position the moss and tundra were rammed back over the ice. The cost of construction of this flume was $1,500, exclusive of the lumber. It is stated that the construction cost much more than it would at present.

At another point, across Manila Creek, an inverted siphon 1,000 feet in length, of hydraulic riveted steel pipe, 40 inches in diameter, ,11 gage, is used for 1,000 feet, at a cost of $10,000. It has a dip of

126 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

150 feet in the center, and the difference between the ends is 4 feet vertically. The allowance for friction made in this siphon was for 3,000 miner's inches of water. At the upper end the water discharges from a penstock 12 by 12 by 14 feet. Another inverted siphon line 300 feet in length, of 21-inch, 11-gage, riveted steel pipe, is laid across Dorothy Creek.

Around Cape Horn there was a considerable stretch of rock work, 1,300 feet in marble. This had to be blasted with powder, and cost $12,000. There are 5 miles of rock work in all along the ditch line. Between Snow Gulch and Glacier Creek a tunnel 1,800 feet in length has been run through the divide to carry the ditch water. Its dimensions are 4 by 6 feet, and it is timbered in places. The top of the tunnel is level with the top of the water on the entrance side, the bottom of the tunnel being run at a low level so as to completely fill the tunnel. All the rock work in the tunnel was done by hand drilling, and in the winter. The rock was found to be frozen 90 feet vertically below the surface. The elevation of the penstock for ' c No. 1 Below Discovery," Glacier Creek, where the bulk of the water was used in 1901, is 113 feet, the surface of the water being about 2 feet lower, the available head at No. 1, below Glacier, being 330 feet. The greatest head of water attainable by this ditch on ground now being worked is said to be 360 feet on No. 2, below Glacier Creek.

The complete cost of the ditch and all accessories, including maintenance for four years, is stated to be upward of $300,000. It is the practice to keep 15 men on the whole length of the ditch system during the four months of the working season. This company, besides the use which it makes of the water for its own mining operations, sells some of its water to the miners on Glacier, Anvil, and Dexter creeks at the rate of $1 per miner's inch under pressure, and at 50 cents per inch for water that has been once used/' According to measurements made with a Price current meter August 23, 1904, the Miocene ditch afforded 1,074 miner's inches above the No. 1, below penstock on Glacier Creek, and 1,752 miner's inches at a point on Glacier Creek above the tunnel leading a portion of the water to Anvil Creek, the inch equal to 1.5 cubic feet per minute.

In the whole of Seward Peninsula there are approximately 175 miles of water conduits, for the most part ditches actually constructed, and fully 100 miles more are reported as under construction or in contemplation. It is safe to say that the work has averaged in cost over $4,000 to the mile, although it is undeniable that with the advantage of experience the operators can build their ditches for less money in future.

Ophir Creek, in the Council district, has been the scene of the greatest activity in ditch construction, as may be seen by the table. There

The miner's inch in this case is reckoned as equivalent to 1.2 cubic feet per minute.

U. S. Geological Surve

Lletin No. 263 Pl

A Pier For Trestle, Hot Air Ditch Line, Ophir Creek.

It. SMALL STORAGE DAM, BONANZA CREEK, KLONDIKE.

purington.] HYDRAULIC MINING. 127

is estimated to be a total of 55 miles of ditches in this basin, including the ditch which taps Pargon River, across the divide. The largest ditch on this creek carries from 1,200 to 3,000 miner's inches, and is through rock and earth for over 18 miles. It was commenced in August, 1901, and work has been done on it at intervals up to the beginning of the season of 11J04. It is estimated by the Wild Goose Mining and Trading Company that on Ophir Creek, in ordinary ground, a mile of ditch a week of this size, 16 by 10 by 3 feet, can be built with 32 head of horses and 70 men. In the 5 miles of rock work which were made along the line black powder was used for blasting. The sod walls were found preferable to rock walls in this ditch, as in the one built by the Miocene Company. The water is used for working several claims, a portion being distributed to each; the head attained varies from 170 to 200 feet in the different operations.

In the construction of the Hot Air Company's ditch line on Ophir Creek several long trestles (see PI. XX, B) were found necessary where the ditch crossed and recrossed the many meanders of the creek. It was necessary to sink the posts of the wrestling in rock-tilled cribs or piers in the creek bed, as shown in PI. XXI, A.

The use of inverted siphons is common in many of the Alaska ditch lines, but presents nothing new over the California practice. The ordinary rules to be observed in conducting water under pressure in pipes, the use of large-diameter pipe to prevent excessive friction, the calculation of the pressure, resistance, the loss of head, and the distribution of air valves are as important as in the case of all pipe lines.

Storage Reservoirs.

Lack of water and of sites at a sufficient elevation to afford head render the building of extensive storage reservoirs in Alaska impracticable. The broad, flat valleys, frozen soil, impervious schist bed rock, and the excellent sod material for dams offer conditions which appear attractive. On the other hand, the small and variable amount of rain and snow (see table 2, p. 18) makes it certain that the expensive surveys and construction necessary for reservoirs whose capacity runs into the millions of cubic feet would never be justified by results.

Small storage reservoirs have been successfully built and have given satisfactory results. The capacity of one built by the Anglo- Klondike Mining Company is 400,000 cubic feet, or sufficient to supply 300 miner's inches for fifteen hours for hydraulicking at a head of 150 feet. The dam is 15 feet high and the reservoir is filled from the supply ditch in from a few hours to three days, according to the rains, which are exceedingly variable. This reservoir, which is built at the elevation of the top of the ancient base-level above the highest gravels, is representative of the best that can be accomplished in this line in the interior

128 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Yukon-Tanana field. Mr. J. P. Hutchins a states that during the summer of 1904 a reservoir was built in the Klondike which has a capacity of 26,000,000 gallons and requires a dam 40 feet in height.

Many small reservoirs (see -PI. XXI, B) are used in the North, affording from 50 to 100 inches of water for a run of a few hours. Reservoirs for the providing of sluicing water for winter dumps have been built on Anvil Creek for catching snow water. In some cases even snow fences have been erected behind the dams to increase the size of the snowdrifts.

The Alaskan miner has at hand the vegetable sod or peat, a material which has proved efficient under Alaska conditions for the building of small dams. The construction of dams is discussed on pages 56-57. In building small storage reservoirs for hydraulicking, it is as necessary in Alaska as elsewhere to determine the proper elevation, to select as large a catchment area as possible, and to take into consideration absorption, evaporation, and the character of the ground and underlying bed rock. The angle of slope for a peat dam, as given by J. T. Fanning,6 is 2.75 horizontal to 1 vertical. Experience has shown that in Alaska, owing to the permanent frost, such dams will stand at a smaller angle, especially if brush is laid alternately with sod. The cost of storage dams in the interior may be reckoned at $1.75 per cubic yard of earthwork, and in Seward Peninsula at $1 per cubic yard.

The expedient of building settling ponds must be resorted to in places where a small amount of sluice water is used over and over for successive operations, as on Anvil Creek, in Seward Peninsula. Two such dams for retaining sediment, one of which is shown in PI. XXII, A, are in. use on Anvil Creek. The water is drawn off from these as often as possible. In the second case it is drawn off at intervals of ten hours to the supply Hume.

Pipe Lines.

In hydraulic mining the water is distributed from the pressure box to the monitors and elevators by means of wrought-iron or, more generally, steel-riveted pipe, usually made up in sections 17 to 19 feet in length. Sheet steel is used, from 8 to 16 U. S. standard gauge, bent, each plate, 30 or 36 inches in length, being riveted in double rwws lengthwise and single on the ends. The sizes used in Alaska vary from 8 to 36 inches. The pipe is shipped by the manufacturers either made up and riveted, as above, ready to be laid with slip joints, or the material is supplied in short plate sections, bent, punched, and furnished with necessary rivets, baled and nested for transportation, ready to be cold riveted on the ground. Fig. 22 shows a form of ship-

Eng. and Min. Jour., Jan. 5, 1905.

Treatise on Water Supply and Engineering, p. 345.

U. S. Geological Survey

Bulletin No. 263 Pl. Xxii

.1. Settling Pond, Anvil Creek, Seward Peninsula.

B. Pipe Line, Atlin Creek, British Columbia.

Jurington.] HYDRAULIC MINING. 129

ping made-up pipe of different diameters which renders it secure from bending or injury in transport. The iron bolt can afterwards be used in the blacksmith shop.

Pipe made up beforehand is coated by immersing it in a bath of asphaltum preparation. This is highly important, and if the operator rivets his pipe on the ground he should dip the pipe in such a bath before laying. Bowie gives the following formula for a bath:

Per cent.

Crude asphaltum 28

Coal tar ( free from oily substances) 72

The advantages of using sheet steel, commonly called " hydraulic" pipe, are its cheapness of construction, adaptability for crossing depressions (as in inverted siphons), the facility with which its position can be changed, and, when slip joints are used, the ease with which the line can be laid. Many engineers do not recommend the use of slip joints — that is, the slipping of the end of one length of pipe 3 inches into the end of the next to form the joint. With average tonography,

wood cap

'- -- !7fT. H

Fig. 22. — Method of nesting made-up hydraulic pipe for shipment.

however, experience has proved that such joints stand great pressure, and the practice is nearly universal among hydraulic miners. Pipe is used for the three following purposes:

(1) As a water conduit, replacing ditches and flumes. Pipe is not recommended for this purpose except where siphoning is necessary or where conditions are particularly difficult for ditching and fluming.

(2) For leading water from the pressure box to the claim.

(3) For leading the water from the gate of a Y to its various points of discharge, as to giants, elevators, and impulse or tw hurdy-gurdy " wheels.

The discharge pipe is generally a nozzle, either manipulated by means of a swivel-jointed tapering pipe called a giant or monitor or fixed within a larger pipe (the contrivance known as an elevator), or acting on the buckets of a wheel.

The thickness of the iron or steel employed is determined by the pressure of the water and the diameter of the pipe. Table 9 gives information concerning a few of the sizes used in Alaska. Prices are those prevailing in San Francisco. Bull. 263- 05 9

130 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263,

Table 9. — Doable-riveted sheet steel slip-joint hydraulic pipe.

Diameter

in inches.

Thickness,

U.S. gage.

Thickness in

fractions of

an inch.

Head, in

feet, pipe

will safely

stand.

Pressure in pounds per square inch due to head.

Weight per foot in pounds.

Price per ! foot, San Francisco,

$0. 23

T6

A

6¥

.,60

T6

A

&

6T

Sh

tl

tV

A

Pipe-reducing sections, Y's, forks, and elbows, and the method of "nesting" pipe for shipment are illustrated by tig. 23 (p. 131). Sections of pipe are put together, as above stated, by slipping, or by flange or lead joints. If it is advisable to reenforce a slip joint, the simple device shown in fig. 24 (p. 132), which can be made quickly in the blacksmith shop, will be found useful. The sleeve, lugs, and key should be made of soft steel.

The disadvantage of diverting water from a straight pipe line may be illustrated by the experience of one of the Alaska operators. It was found that diverting the water from an 18-inch plugged pipe by means of 6-inch Y branch gave an efficient} of 2, while in using the same water through the direct 18-inch pipe choked to 6 inches the - efficiency was 3.

In laying pipe from the pressure box to the claim the line should be started at the lower end and the joints slipped in down the slope. Various methods of "setting" the pipe are in use. The device shown j in fig. 25 is used by Mr. F. H. Brackett, of Atlin, British Columbia. It consists of a square block of timber 3 by 3 feet by 9 inches, faced with one-sixteenth inch steel plate, to which is bolted a disk-like wooden plug the diameter of the pipe inside. Two men batter the timber with

Hvdkailic Mining.

the mallet. Another device used in Oregon for assistance in setting and upsetting pipe is shown in fig. 26. The wrench is made with reversible parts, so that the position of the leverage can be changed for the different operations. Either of these devices can be easily made on the ground.

In cold climates it has been found good practice to lay the pipe line in a slight lateral curve down a slope, so that subsequent contraction of the units may be remedied by pushing the pipe into a more nearly straight line.

In laying the pipe line a funnel-shaped section of pipe for the water to run into is usually provided at the pressure box. This is of light gage and is 6 feet long and from 40 to 30 inches at its larger end. From this the pipe is generally of uniform diameter as far as the Y or iron gate, from which the water is distributed to various parts J of the operations. The pipe should be laid* as j nearly straight as conditions will allow, and elbows 'and bends of small radius should be avoided.

Lead joints are seldom necessary in Alaska operations, but where there are sharp declivities pipe joints must be braced and Strengthened by means of Jugs and wiring, as illustrated in fig. 27. It is seldom possible to lay pipe on the " hydraulic grade line."0 This is "an maginary straight line, extending from a point on the side of the ivater box or reservoir, denominated the velocity head, to the mouth )f the nozzle." When the pipe line departs greatly from the hydraulic £rade line, allowances based on formulas given in the various text )ooks on hydraulic mining must be made for the difference in pressure.

Fig

Forms of pipe fittings.

Pipe cut, formed, ant. punched, to be rivited on ground; 2, pipe nested for shipment; 3, reducing length: 1, circular bend; 5, angular bend; 6, short angular bend; 7, T discharge; 8, angular T discharge;

'.), two-way Y; 10, three-way Y.

"Van Wagenen, op. cit., p.

Gravel And Placer Mining In Alaska.

[Bull. 263.

Where 22- to 30-inch pipes are used it is not advisable to employ less

than 14 gage, even under low heads, as lighter pipe will not bear

handling. The practice of burying pipe, or at least sodding it over,

where the line is to be in place for more than a

season, is recommended in Alaska even more

than in other countries.

Air valves, which can be simply made of leather, hinged to the inside of 3-inch openings in the pipe, should be not more than 300 feet apart. These allow the air to escape when the pipe is being filled and prevent the collapse of the pipe when suddenly emptied of water. Leakage in joints may frequently be stopped by slowly feeding sawdust or manure in at the upper end. In case of collapse of a pipe line, experience has shown that by turning on the water slowly, after closing the lower end, the collapsed sections may be restored to shape for temporary use. The experiment is risky.

PL XXII, B, shows the set-up of a hydraulic pipe line on McKee Creek, Atlin. As may be seen, the line is well braced and rock ballasted, and on steep places the joints are held by lugs and wire guys. The line, which is one of three in use on this propert}r, is of 12-gage steel, is 1,200 feet in length, has a 30-inch mouthpiece at the penstock, and is successively reduced to 18, 16, and 12 inches, the last discharging through the giant. At full capacity the discharge was said to be 700 miner's inches at 170-foot head. The discharge was through a No. 4 Vancouver giant, using 6-inch nozzle, the average twenty-four hour duty being 4 cubic yards of gravel. Along the pipe line side ditches were cut for a short distance to take care of leakage. PL XXIII, A, shows a pipe line led down a hillside on Pine Creek, Atlin.

Fig. 24.— Device for reenforcing joints of pipe.

Wood

)

Wood

r

)

©

hSh

Fig. 25. — Device for setting pipe by battering.

An important fact regarding the flow of water in pipes is the loss of effective pressure at the nozzle due to friction, owing to the use of pipes of too small diameter. The friction of water in pipes increases

U. S. Geological Survey

A. SET-UP OF HYDRAULIC PIPE LINE, McKEE CREEK, ATLIN, BRITISH COLUMBIA.

B. Hydraulic Pit, Klondike Benches.

Hydraulic Mining,

as the square of the velocity and also depends on the condition of the pipes. Even the rivet heads in a pipe Line cause friction and conse quent loss of head. As Mr. George II. Evans a points out, it makes no difference whether the water is flowing up hill or down, or the pressure great or small, the total friction will be materially the same.

zzl

Fig. 26. — Pipe wrench for setting and upsetting hydraulic pipe.

In wooden pipes the friction is nearly double that in iron or steel

pipes. Cox's formula for finding the friction head, which must be

subtracted from the actual head to give the effective head, is as follows:

H=i25bx<4xV!+5V-2>

H =friction head in feet, '/diameter of pipe in inches. L —length of pipe in feet. V=velocity of water in feet per second.

Pig 27.— Method of bracing hydraulic pipe on steep slope

The loss in head of a pipe line 12 inches in diameter, discharging 400 miner's inches, and 5,000 feet in length, is computed by Mr. Evans to be 246.44 feet. Or, if the actual head is 500 feet, the effective head s reduced to 253.56 feet, or an original pressure of 217 pounds per square inch to 110 pounds. To find the velocity in feet per minute in

((Practical Notes on Hydraulic Mining, San Francisco, 1898, p. 25.

134 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263

a pipe, multiply the number of cubic feet of water discharged pe minute by 144, and divide the product by the area of the pipe in square inches. The velocity in feet per second can then be found.

Experiments by Mr. Hamilton Smith a appear to demonstrate that with new and carefully coated pipes, with velocit} as high as 11 feet per second, the loss of head is not significant. Nevertheless, the numerous conditions which enter into the laying of pipe lines on placer mines render the rule that the velocity should not exceed 3 feet per second in the pipe a very safe one to follow. It is a common fallacy among men inexperienced in hydraulicking that an increase in head will increase the amount of gravel which can be moved to the sluice. It must be remembered that the force of the water imparted by head is entirely expended in piping against the face, while the sluice is the governing factor in the moving of gravel after it leaves the face. The aid given by the water in moving gravel to the sluice, and in it is dependent on the grade over which it runs. In small hydraulic operations water is conducted to the pit from the head ditch or penstock by means of canvas hose, known as flume hose, which is from 6 to 14; inches in diameter and weighs from S to 15 ounces per foot. This is used mainly on account of its cheapness and, as a less important con] sideration, because of the ease with which it may be moved about. It is used also for conveying water with very low head, for sluicing purposes.

Flume hose is at best a makeshift and its use is not recommended, except in operations of primitive character in very remote districts. It should never be used to handle more than 100 inches of water or for a head greater than 50 feet.

Giants And Nozzles. Sizes And Prices.

The practice in using hydraulic discharge pipes, known as monitors, giants, and nozzles, does not differ in Alaska from that pursued elsewhere.

Table 10 gives the principal facts necessary for the miner to know about hydraulic giants of the size most applicable for Alaskan work.

"Smith, Hamilton, Hydraulics, 1XS6, p. 314.

Purington.]

Hydraulic Mining.

Table 10. — Water required, effective ivork, sizes, volumes, and heads of water, weights and prices of double-jointed hydraulic giants.

[Prices include two nozzles to each machine and are subjecl to discount.]

s

'So

© P

B

ft

'S,

a

si

ft

w3

"n

N

o

a

o

N

Go

0)

ft

O

©

o

0)

W

©

O)

bo '3

/.

to "8

bo

'Eh ft

List price,

Volumes of water necessary for effective work.

2 be 7*0;

o2

S

o d

3 & o

In.

[ 100

Miner's inches. 1-inch nozzle.

Miner's inches. lj-irich nozzle.

/As-.

l,li

[ 200

r 100

2-inch nozzle.

3-inch nozzle.

$100

$85

2,3

r 100

3-inch nozzle.

4-inch nozzle.

3,4

r 100

3-inch nozzle.

4-inch nozzle.

3,4

r 100

4-inch nozzle.

6-inch nozzle.

4,6

1,000 1,270 1,460

1, 075

About 70 giants of several different makes were in operation in the territory visited during the summer, of which 58 per cent were of size No. 2, using commonly a 3-inch nozzle. In the Juneau and All in districts size No. 4, using 4- and 6-inch nozzle, is used as a rule, while in the interior and Seward Peninsula the sizes 0, 1, and 2, using from 2- to 4-inch nozzle, are preferable. The double-jointed, ball-bearing giant is the favorite type. Deflectors are not commonly used with

Gravel And Placer Mining In Alaska.

[Bull. 26;

sizes below No. 2, while in working on the Klondike benches the prac tice is in favor of butt ends even with larger giants.

The giants used in Alaska are almost exclusively of California man ufacture, although in the Atlin and Klondike districts some of Cana dian make are used. The importance of using water as free ai possible from solid matter in suspension should be considered an( great care should be taken to trap all foreign material at the pressure box. The rifling in the barrel of the monitor and the boring of th< nozzle are also of the first importance, and operators will find i expensive to use other than standard and well-tried makes of giants A method of bracing giant is shown in fig. 28. In soft schist bed rock however, it is frequently necessary to brace with deadman and cable

Scafe

24 f nchea

bed rock

Fig. 28.— Method of bracing giant.

Methods Of Piping To Sluice.

It has been found that some operators in the north are in favor o setting the giant on the top of the bank and piping downstream. ThL is the practice on McKee Creek, Atlin district, and in the Nome anc Council districts. Although the duty attained by the miner's inch does not prove this to be advantageous, it should be remembered tha i the height of bank to be operated on is generally small — from 15 to 5( feet. There is little caving to be done with the pipe, and except ii the case of the rounded gravels of the Klondike " White Channel,'' i is thought that the water under pressure assists in moving the materia to the sluice. Experience does not indicate that the attempt to drive the gravel with the nozzle is very effective.

The various precautions concerning keeping the gravel bank square the prevention of dangerous caves, and the necessity of continuous work during the short season are well known to the hydraulic minei in any country. In working the shallow gravel banks of Alaska r should be borne in mind that the giants must be frequently movec and the tail sluice extended. These operations consume time, and th( most expeditious system possible for performing them should be adopted at the commencement of the short season.

Fig. 29 shows the method of rigging up a hydraulic mine on one of the narrow benches of White Channel gravel bordering Bonanza Creek in the Klondike, and PI. XXIII, B, shows a portion of the ground which has been worked as indicated in the sketch.

,1. Bed-Rock Sluice, Klondike Benches.

B. Blocks Of Frozen Gravel In Hydraulic Pit, Klondike.

Purington.]

Hydraulic Mining.

In piping against a 40-foot bank of frozen gravel, us here illustrated, it has been found good practice to use the giant against a certain part of the bank from two to six hours a day, and allowing the gravel to thaw the remainder of the twenty-four hours. Piping continuously against a frozen bank is awasteof water and power. (See PI. XXIV, B.) The use of powder is of no avail. Even if the gravel is broken off and moved to the sluice in frozen chunks it can not be washed nor can the gold be extracted from it. A combination of water under pressure and of the action of the sun, rightly adjusted, is most effective in thawing frozen gravel. Mr. J. P. Hutchins says that for 200 to 250 miner's inches of water a face covering 50,000 square feet should be allowed on the shady side of hills, while a much less surface will suffice on a sunny slope.

Tail race Fig. 29. — Method of hydraulieking frozen gravel, Klondike benches.

It will be noticed that in the Klondike operations here figured deep trenches or "ground sluices " are cut in the bed rock leading from the face to the head of the tail sluice. The cutting and constant extension of such trenches is a necessity in almost any hydraulic operation, to a greater or less extent, and forms a considerable item of expense. At the time here figured four men in twenty-four hours were employed all the time in blasting out the bed-rock cuts, the expense amounting to not less than $50 a day. In some cases the bench miners have sunk a shaft at a central part of the ground and run a long tunnel on the grade of the sluice, to which all the gravel is moved. Although such tunnels carrying the tail sluice will be from 200 to 500 feet in length, and will cost from $3,000 to $10,000, they will generally be found less expensive than the constant cutting of trenches to connect with the main sluice carried as shown in the plant.

BANK-HEAD WAT Kit.

In no case seen in the North has the amount of bank-head water been excessive. This is a useful accessory to the mining operations, and where it is available should be used. The width of tail sluices should be great enough to allow for excess water, as at times of local rains such water can frequently be obtained and a larger amount of gravel thereby assisted in reaching the sluice.

138 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

PI. XV, B (p. 92), shows hydraulic operations in Silver Bow basin, Alaska, and illustrates the use of the bank-head water.

Duty Of A Miner'S Inch.

This term is applied to the quantity of material moved by 1 inch of water in twenty-four hours. It depends on quantity of water, character of material washed, height of bank, size and grade of sluice, and kind of riffle. many mines the gravel ma}- be easily broken down and carried to the sluice, but may be very hard to move through the sluice on account of a light grade, disproportionate width of box, or the use of obstructive riffles. Thus, according to Bowie, in the North Bloomfield mine the varied from 3.86 to 4.8 cubic yards, withi 100 to 265 feet of bank, sluice 6 feet wide by 32 inches deep, grade 6i inches in 12 feet. At La Grange mines, on the other hand, the duty was from 1.08 to 1.82 cubic yards, height of bank 50 to 80 feet, sluice 1 feet wide, 30 inches deep, and grade 3 inches in 12 feet. In both case* the riffle pavement was principally blocks.

Table 11 (p. 139) is instructive as showing the variation in duty of the miner's inch under the different governing conditions in the North. The duty of the miner's inch in the Klondike is large, estimated at cubic yards in twenty-four hours in the operation described on page 137, with water under 130-foot head and a grade of 12 inches to 12 feett in the sluice boxes, a variable amount of bank-head water from 25 to 100 miner's inches being used. The high duty is accounted for by the fact that the material washed is well rounded, by the absence of large stones, heavy grades to sluices, and the fact that block riffles are generally employed.

The low duties at Nome are accounted for principally by the fact that one-half to two- thirds of the water is generally diverted for use in the hydraulic tailings lifts, and partly by the fact that the gravel is flat and rough. Iron riffles are generally used, but this factor playl little part on account of the short sluices in use.

Purington.]

Hydraulic Mining.

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Gravel And Placer Mining In Alaska,

[Bull. 263.

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pubington.] HYDRAULIC MINING. 141

The duty given above is based entirely on statements made by the operators, and owing to the short amount of running time which has furnished the data, no particular case can be considered of high authority. It will be seen, however, that the different operations in each separate province present a certain amount of agreement.

In stripping operations where the ''frozen muck" is removed by water, ground sluicing appears to be nearly as efficient as the use of water through the nozzle, both iu the interior and Seward Peninsula. This peculiar material, from 50 to 75 per cent ice, is easily thawed when exposed to the atmosphere and to flowing water. It appears rather to be melted than cut away, therefore the impact of a hydraulic stream adds little to the efficiency of a given quantity of water.

It is stated by the Klondike operators that were the "White Channel" gravels unfrozen the duty of the inch would be twice as large. This is not impossible, as the bench gravel presents most favorable characteristics for easy handling. In its frozen state, however, the bank has the consistency of fresh granite.

In Seward Peninsula the instances tabulated are mostly those where hydraulic lifts are employed. The duty has been given in terms of the total amount of water used, including bank head, monitor, and elevator water. In the cases where elevators are used the grade and dimensions refer to the bed-rock sluice leading to the throat, and do not refer to the tail sluice.

Handling Of Bowlders.

The handling of large bowlders in northern hydraulic operations does not present serious problems. Where hydraulicking is possible it is generally found that all the material is small enough to go through the sluice. In the districts visited during the season's work the Atlin district, of northern British Columbia, was characterized by gravels containing large bowlders, which had to be derricked out or sledged in the pit. The practice of "bulldozing" or "plastering" bowlders to break them, by placing sticks of powder on top, covered with a mud cap, is not to be recommended on account of the expense of powder. Sledging into pieces small enough to be sent to the sluice will generally be found the cheapest method, especially as bowlders consisting of hard and tough rocks are not frequently encountered.

Mr. J. D. Hauer, in a recent article,0 states that in general contract work under given conditions the cost of sledging sandstone bowlders varied from 1 to 9 cents per cubic yard; " mud capping" or "bulldozing" costs from 18 cents to as much as 51 cents; "blocking," or breaking by drilling and blasting, costs from 11 to 18 cents; while the method of placing the powder charge under the bowlders costs from

a Engineering News, quoted in Mining and Scientific Press, Feb. 9, 1905.

142 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

15 to 17i cents per cubic }Tard. He recommends the method last mentioned as against bulldozing, or placing charge on top, as powder is saved and there is the additional advantage that much of the rock is thrown out of the cut.

The practice of installing large and expensive derricks as an adjunct to hydraulic mining is not generally recommended for Alaskan work.

Sluices And Gold-Saving Appliances In Hydraulic

Operations.

In the South Coast region the plant of the American Gold Mining Company in Silver Bow basin is characteristic. This sluice, while not in use during the season of 1904, has been operated since 1901, and is typical of the most favorable conditions under which hydraulic tail sluices can be constructed in southeast Alaska.

A 9- by 10-foot tunnel, 3,300 feet in length, was driven through a spur of the mountain from the bank of Gold Greek to tap the gravel pit at the proper depth for reaching the lowest sag in the bed rock. The grade of the tunnel, like that of its contained sluice, is 4 inches to 12 feet. It was driven with air at the rate of 8 feet a day in slate, at a cost of $20 per foot. No timbering is used, with the exception of a few sets near the ends.

The sluice running through the tunnel is 4 feet wTide and 4 feet 10 inches deep, inside measure, of 2-inch native lumber, lined with 1-inch "sand" or lining boards, all lumber planed and sized. The sills are! laid on bed rock, and are 6 inches square and 5 feet long, the posts being also of the same size. Posts and sills are braced by 1 by 8 inch pieces. The sluice is 3,700 feet long from the tunnel entrance and extends for 900 feet up the bed of the pit through the worked-out ground. Bowlders as large as 10 inches in diameter are handled in -j this sluice without difficulty. The amount of water used varies according to the season, but averages 2,500 inches. Riffles are 12- by 12- by 12-inch spruce blocks set on end, separated by If- by 2-inch strips, set on edge and nailed with headless nails. The duty of miner's inch of water is 2 cubic yards per twenty-four hours. The amount of lumber necessary for constructing one box of a sluice, such as the above, approximately 1,100 feet, is probably excessive for the needs of the case. Local conditions in the North frequently result in increased expenditure for the sake of hastening work. About 25 , pounds of nails were consumed to each box, and $10 worth of labor. The cost will not fall greatly below $30 per box of 12 feet, exclusive of cost of tunneling and shooting out the bed rock to grade in carrying up the boxes through the pit. The annual cost of maintenance, including renewal of riffle blocks, which last two years, and renewal of lining boards, is approximately $1,000 a year.

Ptjrington.]

HYDKAULIT MlINTINd

In the saving of the gold, which is fine and rough, 23 Husks of quicksilver are distributed in the boxes. One flask of quicksilver is consumed per month.

Six undercurrents are placed near the end of the sluice, within a length of from 300 to 500 feet of the end. They are transversely arranged, 21 by 14 feet in dimensions, and on a grade of 10 inches to 12 feet. They are furnished with Hungarian riffles — wooden strips with Hat strap iron nailed to the top.

sluice are cleaned up month- .

ly, and in this length 75 per cent of the gold is said to be saved. The remainder of the sluice is cleaned up once a year. The experience with the undercurrents was not satisfactory, as very little gold was caught in them.

It should be especially noted that in the South Coast province the placer gold is of recent origin, is not removed more than a mile from its original source, is low in fineness (in the present case $16.50), and is bright and rough. However finely divided, such gold is easy to save, and the advantage of undercurrents may be questioned. In the interior of Alaska the case is different, as will be seen.

In the Atlin district of

ptlsh Columbia the grades ittainable in the tail sluices ire generall}7 low, from 3 to ) inches to the box length of 12 feet. McKee Creek forms an exception to this rule, the grade being 8 inches in the sluices of both the slants now operating there. The practice of the Amalgamated McKee greek Mining Company on this creek is as follows:

The sluices, of which there are two, are 600 and Too feet long. The rade is 8 inches to 12 feet, and the inside dimensions of the sluice, exclusive of lining boards, are 29 inches wide by 3Sj inches deep, as

lustrated in fig. 30.

OOEZXil

;

Fig. 30.— Sluice box used on McKee reek, Atlin, British Columbia.

144 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

The amount of lumber in a sluice box like that figured is as follows:

8 posts, 4 by 4 inches by feet. 4 sills, 4 by 6 inches by 6 feet. 16 braces, 1J by 4 inches by 1 foot. 1 top rail, 1£ by 8 inches by 12 feet. 16 post straps, H by 2 by 4 inches.

3 bottom boards, 1£ by 8 inches by 12 feet.

1 bottom board, 1£ by 4 inches by 12 feet.

4 side boards, 1 by 8 inches by 12 feet. 6 side boards, 1? by 8 inches by 12 feet.

2 lining boards, 1£ by 8 inches by 12 feet. 48 riffle blocks, 8 by 8 by 12 inches.

16 riffle strips, 1 by 3 by 28 inches.

Each box, with riffle blocks, contains approximately 540 feet of lumber.

The use of 8-inch lumber is a necessity if native timber is used, 12- inch lumber being very scarce and the expense of employing it prohibitive. The cost of each box, including riffles, averages $25, sluice lumber being $45 per thousand and the riffle blocks costing $6 per box length. The setting of the riffle blocks with alternate spacing, as represented, is said to be advantageous, causing a cross circulation and consequent stirring action. The riffles are nailed in sets of three to a riffle strip outside the flume, and are piled up ready to be put in position as occasion demands. Pole riffles, 12 feet in length, made of 3- by 3-inch strips, set with a right-angle uppermost and shod with angle iron, are used in a portion of the boxes. A space is left between the lowest angle and the bottom of the box, the long strips being set with a gain into cross strips, 6 feet apart. The blocks are being gradually replaced by this type of pole riffle. The gold is coarse, and il is said that undercurrents would be of no advantage. In the first bos 85 per cent of the gold is caught. In the first five boxes all the gold is caught which pays to clean up. In one clean-up $25,000 wa caught in the first box, as against $1,900 in the remainder of the 700 foot sluice. The clean-up of the upper two boxes takes place once h two weeks. In this sluice the miner's inch is said to have a duty of i yards. A new box is put on the end of the tail sluice ever}T tw( days. When the end of the sluice is spread into Y's, a hinged gate with steel plates on both sides, is used for diverting the water an( tailings into one or the other branches.

Experience on McKee Creek appears to show that the gold is savec in a comparatively short distance. Yet gravel miners in Californii maintain, and with apparent reason, that the longer the sluice th< more gold will be saved. For example, at the Hidden Treasure drif mine, in Eldorado County, Cal., it was stated to the writer that tin 2,500 feet of sluice boxes, 19 by 21 inches in the clear, with iron ca wheel and rack riffles, and an undercurrent attached, were insuflicien

pubington.] HYDRAULIC MININO. 145

to save the gold. The sluice has a grade of 14 inches to 12 feet, and 90 pounds of quicksilver were used in charging the sluice.

The percentage of gold in the upper 120 feet of the sluice was as follows:

Per cent.

In upper 1 foot 75. 0

In upper 10 feet 8. 4

In next 50 feet 9. 6

In next 60 feet 2. 0

This portion of the sluice was cleaned up monthly, and was furnished with old car wheels, regarded as the best riffle, and with iron Hungarian riffles.

The upper 1,000 feet of the sluice was cleaned up once in three months, and the whole sluice and undercurrents annually. Five per cent of the total product was obtained from the lower 2,380 feet paved with quartz stones, and it is estimated that an amount equal to 2 per cent of the total product escaped into the canyon below. It was stated that one-half mile of this canyon was leased to the Chinese for $5,000 per annum, who cleaned up at a profit the gold which had escaped. The undercurrent was not regarded as of great value, except for the saving of excessively fine gold and free quicksilver and gold with quartz attached.

Mr. W. M. Johnson informed the writer that in Nevada County, Cal., in the case of a sluice miles in length, the first live out of a total of seven undercurrents proved an economic success, the last two hardly paying to clean up. It was found best to clean the five undercurrents at intervals of two weeks.

The experience on Pine Creek, Atlin, in the matter of saving gold is not so satisfactory as on McKee Creek, according to operators' statements. PL XXIII, A (p. 132) shows one of the 120-foot sluices of the Pine Creek Power Company. It is 5 feet b}7 40 inches, has a grade of 5 inches in 12 feet, and is paved with block riffles. The undercurrent, 14 by 24 feet, on a 10-inch grade, was one of the few installations of the kind seen in the northwest. It was understood to be but the beginning of experiments aiming to save the fine gold that escaped with an excessive amount of black sand. The amount of gold recovered is 43 cents per cubic yard, as stated, and the Opinion was expressed that a large percentage of fine gold escapes. The undercurrent itself had not been installed a sufficiently long time to determine its efficiency.

The Atlin gold is derived from older gravels through which the present streams cut. The gold is for the most part coarse, but is well rounded. That a certain percentage of it is tine, specimens collected show. It is very probable that an undue proportion of such bench |gold will escape from a sluice of the short dimensions figured. Bull. 263—05 10

Gravel And Placer Mining In Alaska.

[Bull. 263.

Dropoffs are not used in any of the sluices seen in Alaska or the North. Grade is lacking-, it is true, yet in the case above mentioned there was a space of 25 feet vertically between the end of the sluice and the creek bed which served as the floor of the dump. One or two drops of 6 inches in the short sluice would seem entirely practicable, and would certainly be advisable. Cemented gravel does not occur generally at Atlin, but layers of clay are found in the pay streak. Such clay can not be properly disintegrated in a short sluice, but will roll in balls through the entire string of boxes, carrying with it not only the gold inclosed in its mass, but picking up gold already lying at rest.

A useful device to tighten the bottom boards of sluice boxes before nailing is shown in fig. 31. It is claimed that no tongue and groove are necessary with this appliance.

In the Atlin district the mining operations are hindered by heavy floods in the early part of June. At the property of the Societe Miniere on Bowlder Creek, it is the practice to cover the sluice with

Fig. 31.— Side-board tightener used in making sluice boxes, Atlin, British Columbia.

a series of small protective dams, so that the debris brought down by the annual flood may not injure the boxes. This debris is afterwards piped off, at the cessation of the high water, and the dams are then removed.

The following details of this plant were kindly furnished by M. Henri Maluin, of the Societe Miniere de la Colombie Britannique, and will be of interest:

The property on Bowlder Creek operated by the Societe" Miniere de la Colombie Britannique is situated in the Atlin mining division of the Cassiar district, British Columbia,' 12 miles from the town of Atlin, on Atlin Lake. Operations were started in June, 1901, and the property has been worked continuously during the open season up to the present time. The product of gold has been 3,440 ounces, worth $16.63 per ounce. The gold is rather coarse, and nuggets up to 10 ounces in weight are found. Work is carried on both in the present bed of Bowlder Creek ami on benches lying at approximately the same level as the creek bed. The gold-bearing channel is about 150 feet wide, the grade of the creek bed varying from 6 per cent to as high as 10 in the upper end. Where work is now carried on it is 6.1 per cent.. The depth of ground averages from 25 to 50 feet, of which the lower 6 feet is consid-

puringtojt.] HYDEAULIC MINING. 147

ered the pay. The bedrock is a soft slate of greenstone variety, although granite occurs at the head of the creek. The gravel to be moved is rather heavy in character, stones from 18 to 30 inches in diameter composing 50 per cent of the mass, though the usual diameter of the stones approximates 6 inches.

In the season of 1904, a season being reckoned at 100 days, with 400 miner's inches of water available, 40,000 cubic yards of gravel were moved, at a cost not far from 50 cents per cubic yard. It is expected that mining will be done in the future for 40 cents per cubic yard, including all expenses. Mr. Maluin states that 35 cents would be a low estimate for the Atlin district, in general, for hydraulic work under the conditions obtaining on Bowlder Creek. Dirt is occasionally moved for 10 cents a cubic yard, and again patches of hard gravel are encountered which cost over a dollar.

An average of 25 men are employed during the summer season at wages of $3 per day of ten hours, and board. The season is open from June 1 to September 15. Spruce and pine are obtainable on the property, though it is difficult to obtain boards wider than 8 inches. Sawed flume lumber costs $40 per thousand.

The water for hydraulicking purposes is brought to the claim from higher up in Bowlder Creek by a flume 3,000 feet in length, size 24 by 24 inches, having a grade of 1 inch in 12 feet, It has an estimated capacity of about 700 miner's inches, but actually 400 inches is generally available at 150-foot head. The pipe line is 16-inch steel to the Y, then 14-inch to the two giants. Vancouver pipe is used, but the giants are California make. The average height of bank is 50 feet, and the giants have no difficulty in cleaning bed rock.

The sluice is 1,400 feet in length and cost $6,000. It is 24 inches wide on a grade

of 4 per cent, corresponding very nearly to 6 inches to the 12 feet. Bottom boards

are 1£ inches thick, sides H inches thick, while sills and posts are 4 by 6 inches.

It is possible to keep a drop below the end box of 35 feet for dump. In piping,

the head box is kept within 30 feet of the bank, and four men for one-half day are

teeded to place a new box at the head. Block riffles are used at the head of the

luice followed by rails. Very little quicksilver is necessary, and it is found that no

old is recovered beyond 250 feet of boxes. Undercurrents are not used. Bowlders

ire removed from the pit by flat hand cars running on a steel track. If too large for

his, which is seldom the case, they are plastered and shot with 75 per cent dyna-

nite. The company is now in good shape to operate for a period of years, and esti-

nates that the cost will not exceed 40 per cent of the product.

The company leases a portion of its ground where the situation is not advantageous or hydraulicking, and this is drifted. Although the drifting operations are carried under great difficulties and require close timbering, the work is said to have been >rofitable.

In the hydraulic mining of the "White Channel" bench gravels of he Klondike, the small amount of water available, generally from 100 200 miner's inches, necessitates steep grades to the sluices. The fold is recovered with comparative ease because the bench gravels, fter being thawed, are easily disintegrated and washed, and clay is bsent from the pay streaks. The sluice shown on PI. XXIV, A, is arried in a cut in the outer rim rock, on u grade of L2 inches to the ox length of 12 feet. Twelve to fourteen boxes are ordinarily used. 'he details of the sluice are as follows: 24 inches wide by inches eep, bottom of 2-inch and sides and lining of 1-inch lumber; posts rid sills 2 inches square; sills set in bed rock; riffles of spruce blocks I inches high and 9 inches square. These cost 25 cents apiece and last

148 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

one season. Through this sluice 1,000 cubic yards are washed in twenty-four hours with 250 miner's inches of water. It is stated that 90 per cent of the gold is saved in the upper 6 boxes, only 1 per cent of the total gold being lost. The gold is mostly coarse and rough, but very fine gold is found.

In the case of another operation working the Bonanza Creek benches it was stated that gold was found the entire length of a 2,000-foot bed-rock sluice, followed by 500 feet of 2-foot wooden sluice, on grade of 11 inches to the box length. Block riffles were used in the wooden sluice. A small nugget was picked up 2,000 feet from the head of the sluice. Another operator, using 360 feet of 20-inch sluice boxes, on 12-inch grade, with iron-shod pole riffles, said that 2 per cent of his gold was escaping, and he was of the opinion that the installation of anundercurrent would pay.

In a hydraulic operation using 500 feet of boxes, 2 feet wide, 12- inch grade, with block riffles, and working a portion of the ''White Channel" gravels where the gold is very fine, bright, and smooth, it was said that 80 per cent was caught in the top box, 85 per cent inside the first 15 boxes, and that none was found in the two end boxes.

In a bench hydraulic operation on Last Chance Creek, Klondike, a .small undercurrent with cocoa-matting riffles had been put in after 400 feet of 2-foot sluices, with 12-inch grade, using block riffles. The undercurrent had given very satisfactory results, and a larger one was being constructed in addition. a

The above data indicate that where hydraulicking is possible in the Klondike, the gold-saving appliances are fairly adequate to the needs of the operations. As all hydraulic mining in that region is limited to i ancient channels lying at an elevation of 200 feet or more above the present streams, water is exceedingly scarce, and sluicing methods must be adapted to this condition. These methods also depend on the necessity of impounding tailings on steep hillsides (see PL XXV, B), . the high cost of labor ($7.50 a day), and of lumber ($80 per thousand feet), the necessity of making quick and frequent clean-ups, and the different economic ratio which obtains in recovering gold from small patches of rich gravel as distinguished from large bodies of low-grade gravel. When it is well established, therefore, that no great percent-' age of gold is escaping, it is likely that the extra cost of installing and maintaining complicated saving appliances would overbalance the increase in gold recovered. The use of drops in the sluices, and lessening of grade, might, it is likely, result in an increased saving, with no extra expense of maintenance, except in the wear of riffles at certain points in the sluices.

aSee Bowie, A. J., jr.: A Practical Treatise on Hydraulic Mining in California, p. 231, for full description of undercurrents and the method of leading gravel to them from the main sluice.

U. S. Geological Survey

Bulletin No. 263 Pl. Xxv

A. Sluice Below Elevator, Ophir Creek.

B Retaining Dams, Bonanza Creek, Klondike.

PrRIN'GTON.l

Hydraulic Mining.

In hydraulic elevator practice as pursued in various parts of Seward Peninsula, Alaska, short sluices are in use. I [ere, as elsewhere, a sluice is generally set in bed rock on a grade of inches to 12 feet, or near this grade. On Ophir Creek, in the ( ouncil district, Alaska, the practice is to use from 10 to 12 boxes of 12 feet length, 24 inches wide and LG inches deep, with wooden rail or pole rimes, shod with strap iron. This leads to the elevator sump, 10 feet deep. The position of the elevator with reference to the sluice below it is shown in PI. XXV, J. The tail sluice following the elevator in the case specified is 28 feel higher than the head sluice. The tail sluice consists of five 24-foot boxes, 4 feet wide, and the practice is to give the first box either no grade, or a grade not exceeding 2 inches. The other boxes are graded from 2 to 5 inches successively, a 5 inch grade being retained for all below the fifth box, if more are added. On Ophir Creek, where there are six elevator plants in operation, iron rimes are generally used in the discharge sluice. A type of riffle which is used in the head box is made of railroad iron, cut in short pieces and set transversely in

It

-- 6ft-

Scale

2 feet

Fig. 32.— Rail riffles used in Seward Peninsula.

the box, forming a Hungarian riffle. Another kind in much favor throughout Seward Peninsula is composed of a set of T rails, in sets of 4 laid lengthwise (see fig. 32). These are made with a locking attachment, and are put in the sluice upside down. T angle-iron riffles, made in 1-foot square castings, laid in the- sluice so that the slots set longitudinally, and with the flat side uppermost, are also very satisfactory and durable, and on account of their lightness facilitate, the clean-up.

The proportion of gold caught in the head and tail sluices varies according to the practice. At Claim No. 2, below Glacier Creek, the gravel is run through 250 feet of iron boxes, only the two lower of which, next the elevator sump, contain riffles. These iron boxes are 10 feet long, 31 inches wide at the top, 27 inches at the bottom, and 8 inches deep, of a single bent sheet of iron, lapping 2 inches at the ends and fastened together with two bolts. The material slides easily through the cut in these, which are laid on 6-inch grade to the elevator. It is said that 50 per cent of the gold is caught in the last two of these, and 50 per cent is caught in the tail sluice after the elevator.

150 GRAVEL AND PLACER MINING IN ALASKA. [btjll. 263]

In the elevator operations on Ophir Creek and on Basin Creek, in the Nome district, it is said that 75 per cent of the gold is caught before the elevator, and in one case no gold was caught below the firs! four boxes of the tail flume. The experience in Seward Peninsula has shown that tin1 gold is for the most part rough, and even crystalline, and even when finely divided is saved with ease. One marked exception was seen at Anvil Creek, where a 500-foot string of boxes on tti-inch grade caught gold for the entire length.

Tailings.

It has been said that the most important part of the equipment of a hydraulic mine is the dump. It has been found that the amount of material which can be moved is governed primarily by the grade of the sluice boxes. Reference to table 11 (p. 139), shows that there is a fairly constant ratio between the grade of the tail sluice and the amount of gravel moved through it per twenty-four hours per miner's inch of water used.

Since it is a prime necessity in hydraulic mining operations that as large an amount of gravel as possible shall be delivered through the tail sluice and disposed of on the dump, it is evidently of the highest importance that a steep grade, 12 inches in 12 feet if possible, and on no account less than 6 inches to 12 feet, should be available for the sluice. It is manifestly impossible to secure this grade if the natural slope of the ground or creek bottom over wdiich the material is run is less than that required for the sluices. The grade of the surface must in fact be more than that of the sluice, in order that there may be ample vertical space below the end of the lowest box for the tailings.

In hydraulic operations on bench gravels, as, for example, in the Klondike region, the conditions for obtaining grade for the sluices are more favorable than in any other Irydraulic operation of the North. The gravels of the Klondike White Channel benches are easily moved after they are thawed. This is fortunate, as on account of the small amount of water available hydraulic mining on the benches would otherwise be impossible. The expense of keeping up dams for impounding tailings, however, is considerable. Naturally the barren tailings, consisting of white quartz stones of the size of paving stones, can not be allowed to wash and slide down to the creek bottom. Were this permitted, the creek miners would soon find their cuts flooded and their ground covered with thousands of tons of useless debris. Therefore impounding dams for tailings must be constructed of the strongest available materials, in order to resist the weight of the stones. The cost of building tailings dams of brush and poles, 20 feet high, in the Klondike, is $5 per linear foot. Retaining dams along Bonanza Creek in the Klondike are shown on PI. XXV, B.

purington.] HYDRAULIC MINING. 151

In California hydraulic mines the dump, even after a scries of dropoffs 25 feet in height, was sometimes in a canyon hundreds of feel vertically below the end of the sluice. The remarkable topographic conditions which allowed of such a phenomenal dump probably can not be found in another placer country, and certainly not in those portions of Alaska here considered. Even in California, however, it was often found necessary to distribute the dump by means of Y\s near the end of the tail sluice. One such system is in practice on McKee Creek, Atlin, and has already been referred to. In hydraulic operations where 1,000 cubic yards or more a day are handled with low dump two carpenters have frequently to be employed at least half of the time in adding boxes to the tail sluice. If the dump be properly spread in delta form, the operation can be carried on in places where otherwise it might be impossible.

Where hydraulic operations are conducted in creek beds of low grade, below the so-called "sluice-box grade," or 6 inches in 12 feet, some expedient must be adopted to get rid of the accumulation of tailings below the end of the sluice. If the topography is such that the water runs off and only the solid residue of the tailings accumulates, the expedient is sometimes adopted of "piping" the dump away with an extra giant set in a convenient position for the work. This giant generally requires the services of one man, and, although used only a portion of the time, may be figured under Alaska conditions to add from 2 to 5 cents to the cost of handling the gravel. The efficiency of the plant is detracted from by so much power as is required to push the tailings out of the It can not be too strongly insisted on that when this or any other device is used to move or elevate the tailings, the strict principle of hydraulic mining is departed from. The use of the steam or horse scraper in removing the tailings of small plants is discussed on pages 70-72.

If the grade of the creek bed is lower than that necessary for the sluice, the tailings must be elevated and the water pumped from the pit. Mechanical elevators with the addition of a bed-rock drain are sometimes used, though not with success, so far as known. In one case on Mastodon Creek of the Birch Creek district the installation of a steam scraper for lifting the tailings from the hydraulic pit was contemplated, the water being bandied by a bed-rock drain, which had been installed at great expense.

The Hydraulic Elevator.

The hydraulic elevator is too well known to need elaborate description. The principle is the same as that of the injector. Water under pressure discharged through a nozzle set w it hi n a steel jacket creates a vacuum and causes Avater — about one-half the quantity used by the elevator — and accompanying solid material to rise to a height corre-

152 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

sponding to approximately 10 per cent of the head under which the water acts. Many elevators have been used, and they all act on the same principle. One of the necessities is the constant admission of air with the tailings, which, by being compressed, aids in the elevatingprocess. Those elevators are considered best which admit air most freely .

An exceedingly simple form of hydraulic elevator — the so-called "open" elevator — is in use in southern Oregon. The gravel is piped directly into an inclined box 8 by 30 feet in dimensions, which has a false bottom of punched iron plates. All the fines run back on the plank floor of the box to the undercurrent, the oversize falling to the tailings pile at the raised end of the box. The contrivance is a makeshift, but is said to be successfully used in the flat stream beds of southern Oregon.

A hydraulic elevator will sink a pit in a flat piece of ground containing no large stones. In starting new work on placer ground it is, in fact, the practice to sink the pit with the elevator. The portion of the hydraulic elevator shown in PI. XXVI, A, is in position in the bottom of a pit 40 feet deep, on Glacier Creek, Seward Peninsula. This pit, which is 90 by 60 feet in dimensions, was sunk in ten days by a 7-inch elevator, smaller than the one shown in the picture, using 325 miner's inches of water at 360 feet head. At the claim next higher up the creek a similar elevator was in use, and a description of its operation will be of interest. Seven hundred and sixty miner's inches, under 330 feet pressure, were used in the operations. The water is afforded by the Miocene ditch, described on pages 123-126. The grade of Glacier Creek does not exceed 50 feet to the mile in its lower portion, where this property is worked. The gravel deposit, which is wide and 20 feet in depth to bed rock (see PL XXVI, B), can not be worked by the hydraulic method on account of the impossibility of disposing of the tailings. Therefore a long cut is ground-sluiced off to the depth of 6 or 7 feet below the surface. The elevator sump, which must be about 5 by 5 feet and 10 feet into the bed rock, is sunk in the bottom of the large pit. The elevator, which, with the head above given, lifts 36 feet, is set in position. For this ground a No. 1 elevator, having a 10-inch throat and using 4-inch nozzle, is employed.

The hydraulic elevator, like the one shown in the photograph, is by no means simple. It consists of 15 large parts, some of them very heavy, and a number of rods, bolts, bands, and wooden staves. The cost of the one shown is approximately $750 in San Francisco, and the weight is 2,000 pounds. A pipe is led from the supply pipe to feed the nozzle of the elevator. It is connected to this by means of the ball joint. This joint, shown in the photograph, is exceedingly convenient, as it allows the pipe to enter the pit from one of several directions. Where the upcast pipe joins the top casting of the elevator it

U. S. Geological Survey

Bulletin No. 263 Pl. Xxvi

A. Hydraulic Elevator In Pit, Glacier Creek.

B. Gravel In Pit, Glacier Creek.

Pitrington.

Hydraulic Mining.

should be made to fit over and outside of this casting, so that there will be' no leak. The casting should be rimmed outside to a depth of 2 inches. The jacketing of the nozzle is considered very good practice, as it prevents smothering with gravel. In the type of elevator here shown the advantage is claimed that the various parts, lining, hacking, first section above throat, top section, etc., are separate and merely lit together, being held by a ring of wooden staves, as shown in PI. XXV, A. This obviates the use of heavy castings. The upcast pipe is made of lap-welded steel, one-eighth inch in thickness, and either lead or flange joints can be used. In the plant described the pipe was in 18£-foot lengths and the joint was made by bolting together wooden blocks, 10 by 12 by 24 inches, with a half-round cut made to admit the pipe. The upcast pipe should be set at an angle of 60°.

By far the most important parts of the elevator as regards wear are the throat and the hood which receives the impact of the gravel in the

!

iPL

r—

°\m

1 ! !

ni\ 'K iH

if

2 feet

Fig. 33.— Hood in head box of tail sluice.

head box of the tail sluice above. These two parts are manganese steel castings, and if the gravel is very sharp and siliceous may wear out in one season. For the 10-inch elevator the throat weighs 400 pounds and the hood 600 pounds (price 16 cents per pound in San Francisco). The manner of setting the hood in the head box of the tail sluice is shown in fig. 33. The upcast pipe is laid against an inclined framework of four lengths of 2-inch plank 2 feet wide, and extends directly into the bottom of the tail sluice. (See PI. XXVII, .1.) Leading to the throat of the elevator directly above the nozzle is a sluice box, which conducts the gravel either from the boxes preceding it or from a bed-rock sluice, which is carried back on grade in the pit bottom as fast as the gravel is piped down. On Glacier Creek the gravel is led to the elevator in 24-inch iron boxes on 6-inch grade, with or without rail rimes. After leaving the discharge of the upcast pipe the gravel passes through eight or nine 36-inch boxes, with T-rail rimes. The first

154 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

two boxes have 4-foot .sides, reinforced inside and out with sheet iron, and are set high on a trestle to give the desired elevation for maintaining the dump. The grade is either 0 or 1 inch in 12 feet for the head box, 2 inches for the second, 3 inches for the third, 4 inches for the fourth, and 5 inches for the succeeding boxes. It is proposed to supplant wooden sluice boxes on this claim with iron boxes 8 to 10 feet long and from 2 to 3 feet wide, of one-fourth-inch sheet iron, weighing from 500 to 600 pounds each and costing" from $15 to $20 in San Francisco. Five hundred and twenty miner's inches of water are used for the elevator and 240 inches are used through the 3-inch nozzle of the giant. The water is distributed from the suppty pipe by 11-inch pipe to the two nozzles. By this arrangement 500 cubic yards of gravel can be handled in ten hours. It is said that the elevator is not handling over one-half the gravel that could be put through it if the larger amount could be moved to the throat. Experiments with scrapers operated by water power are in progress.

The practice here is first to run back with a narrow cut 250 feet up the creek from the elevator throat, then to come forward toward the elevator, breaking- down the sides.

If the cut is 150 feet wide, 250 feet long, and 25 feet deep, a new set-up must be made every thirty-four days, assuming that the plant is run all the time at its full capacity. To make the new set-up of boxes and to build the trestle requires $400 worth of lumber and the labor of 5 men for five days. In addition, it takes the whole crew of the placer one day to take the elevator from its old position and place it again. The total extra expense is, then, nearly $1,000 in money and at least one full day out of the short working season each time that the elevator is moved.

In Seward Peninsula the handling of bowlders gives little trouble with the elevator. A 10-inch throat will take a 9f -inch bowlder. It is not uncommon to see the men near at hand throwing small stones down at the throat of the elevator. This is because stones are jammed in the throat. The elevator for the moment is not clearing the pit, and the small stones artificially fed will act as small cannon balls to break the obstruction.

It should be noted that a very large amount of water is used for the elevator as compared with that used for the giant. It has been found most economical to distribute the water one-third to the giant and two-thirds to the elevator. If the elevator is too large for the water used, the employment of a choked nozzle or smaller nozzle will obviate the difficulty, while the larger throat does no harm. One of the most common difficulties with the hydraulic lift is the fact that it will choke if required to raise too much seepage or pipe water.

Elevator practice in hydraulic mining has been so limited in its application, and has met with so little success, that definite rules for

U. S. Geological Survey

Bulletin No. 263 Pl. Xxvii

A. Hydraulic Elevator.

B. Open Cut Worked By Tramming To Bed-Rock Sluices.

156 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

claim, with almost precisely similar geological conditions, where gravel was being handled by shoveling into li-yard derrick skips trammed on trucks to the derrick, lifted to a sluice, and washed with gravity water. Now, grant that the cost of the derrick plant was $10,000 while that of the elevator plant was only $5,000. The water for the elevator, however, 500 miner's inches, represented one-tifth of that obtained by an elaborate ditch system, the proportionate charge of installation of which was $60,000. It is very unlikely that the life of either of these properties will exceed six years, and it can be easily seen that the amortization charge for cost of plant must be, less interest allowance, $17,000 in the elevator plant, as against $10,000 in the derrick plant.

It would be unfair to entirely decry the use of the hydraulic elevator in Alaska. On the other hand, it is a deplorable spectacle to see cases where expenditures of from $25,000 to $200,000 have been made to secure the use of water at a head, where the elevator is installed, and where it finally becomes apparent that loss will result in the operations because gravel can not be moved to the elevator in sufficient quantity.

To take a very typical Alaskan case, assume a body of material which, handled at the rate of 700 cubic yards a day, can be worked out in six seasons; that the section consists of 2 yards of muck and of yards of gravel which has a tenor of $3 per cubic yard. This material can be all handled by the hydraulic method at an expense of 50 cents per cubic yard, actual working cost, including superintendence. In order to make this hydraulic method available a ditch carrying 1,000 miner's inches of water at lowest stage must be built at a cost of $100,000. Let this cost include the hydraulic equipment. Simple interest charge on the investment and maintenance of ditch and plant will amount to $90,000 additional. Allowing nothing for purchase of property, the five annual payments to amortization of plant fund will amount each to $38,000. Allow one hundred days each season actual working time. Then the amount per cubic yard which must be added to cover payment to the sinking fund will be 0.542 cents per cubic yard, or a total of $1,042.

This cost will not be regarded as extreme by those who have had experience in similar undertakings. The operator has a choice of mechanical plants, by using one of which he could work the ground with great economy. In other words, the use of the h}- draulic elevator in Alaska frequently defeats the object for the attainment of which the hydraulic method of mining is employed.

purington.] GEAVEL AND PLACER MINING IN ALASKA. . 157

dim: DOING.

Introduction.

The opportunities for gold dredging in the far Northwest are not by any means numerous. Perhaps no part of the gold-mining industry is dependent on so many conditions for its financial success as the dredging of auriferous gravel deposits for gold. Some years ago, in connection with Mr. J. B. Landfield,® I published a review, setting forth the geological conditions which are necessary for the success of gold dredging, the consideration of which is frequently neglected by those contemplating the installation of dredges. The portions of that paper which deal with the present case are here quoted. The prime consideration is that conditions of a peculiar character are a necessary accompaniment of the values in any locality where it is proposed to win gold by dredging. Recent experience has proved that the greatest attention must be given to topographic and geologic conditions in the country in which the enterprise is to be inaugurated, otherwise success in the operations is not to be looked for. The following explanation of the conditions necessary for dredging is therefore pertinent:

Taking the country about Oroville, Cal., as the best example in the United States, let the geological conditions be considered. To the north and east the erosion of a vast extent of mining country, whose rocks are penetrated by gold-bearing veins, has contributed little by little through geologic ages to the mass of detritus now occupying the bed of Feather River. The wearing down of mountains, originally very much higher than at present, through a vast amount of time has caused the formation of a valley of extraordinary width but of no great depth. The massing of stream detritus is also responsible for a decrease in the gradient and a slowing down almost to a topographical equilibrium of the formerly swift current of the river. The stream, unable under these conditions to cut its way by virtue of the material which it carried in suspension, has for a long time been depositing its load, filling its wide valleys with sand and gravel, together with the less destructible of the metallic particles, and notably gold. Geologically speaking, the rate of deposition of the river's material may be said to be on the increase and the current of the water, still of considerable velocity, to be greatly lessening in swiftness. Later in its geologic cycle Feather River will doubtless assume, on a smaller scale, the present character of the Mississippi, forming oxbow curves, cut-offs, and, as it were, losing its way among constantly shifting sand bars.

The accompanying residual gold, as it travels to a greater and greater distance from its original source in the veins of the mountains, becomes more and more finely divided, even to microscopic dimensions, and increases in purity, and the degree of evenness with which the particles are distributed in the gravel becomes a phenomenon of constantly increasing definiteness and importance.

Such a set of conditions as that obtaining on Feather Iiiver is the exception rather than the rule in the western part of the I Fnited States, and even in California. The above explanation has been entered into in order to present in some measure the reasons why, on the California river referred to, the conditions are not only favorable but eminently suited to gold dredging. Shallow gravels- that is, those less than

" Purington, C. W., and Landfield, .7. B., jr., The gold-dredging fields of eastern Russia: Eng. Mag., vol. 22, 1901, pp. 398-407.

158 . GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

40 feet in depth — are an essential in dredging enterprises. Thus broad rather than narrow, gorge-like valleys must he sought. Bed rock of a soft, decomposed character, which can be easily cut into by the dipper or bucket of the dredge, is a necessity, since placer gold, by virtue of its gravity, often sinks from 1 to 2 feet into the crevices of the rock underlying. It is hardly necessary to state that the amount of gold increases in geometrical ratio the lower it lies in a given bed of gravel. Thus old rather than young valleys are favorable for dredging.

Additional reasons of great weight why geologically old valleys should be looked for are that the size of bowlders is greatly decreased, gravel becomes by long abrasion uniform in size, the angularity of the fragments disappears, and a bed of pebbles, round and easily handled, is the result.

The even distribution of the gold which, as mentioned above, is an invariable accompaniment of old and wide valleys, is a point in favor of this sort of mining, looked at from the standpoint of a business enterprise. At the same time it is evident that the finely divided state in which such gold is found necessitates the highest skill in recovering it, For example, at Oroville, although some of the operators are saving gold the subdivision of whose particles is almost microscopic, it is thought with good reason that a considerable percentage of values is lost in the water used for the washing.

The conditions on Yuba River in California are, from the dredging standpoint, as favorable as those at Oroville.

The conditions above mentioned as important to the success of gold dredging should be taken account of as much by the men who contemplate installing dredges in Alaska, as in any other part of the world. While it is true that there are in Alaska broad valle}rs, such as those of Yukon River and its larger tributaries, and that they have been found to be to a certain extent gold bearing, yet peculiar and formidable conditions serve as a barrier to the exploitation of these streams by dredging. A remarkable illustration of this fact came to my notice during the last summer. In a small island facing the settlement of Eagle, in the interior Yukon country, a shaft sunk through rolled stream gravel to a depth of about 40 feet in winter penetrated perpetually frozen ground until near the limit of its depth. At this point an underflow of water was encountered so strong as to prevent further prospecting. It was said that good values in gold, even up to $1 to the yard, were found in sinking this shaft. If this be true it would imply that considerable areas of the underlying immensely wide gravel flats of Yukon River are gold bearing. Under other conditions portions of the ground might be found workable by gold dredges. Experience has shown that in Alaska the permanent frost which exists in much of the river country renders the exploitation of the gravel by ordinary mechanical means absolutely impossible. It is the opinion of those who have attempted the dredging of frozen gravel in the Klondike that, while the devising of a dredge strong enough to dig frozen gravel is not impossible, the undertaking has not yet reached

a Since the above was written the enlarging and strengthening of dredges has resulted in successful digging (on Yuba River, California) to the depth of 60 feel . 1 1 should be noted, however, that the upper 25 feet of the Yuba gravel section consists of loose tailings.

pubington.] DREDGING. 159

even the experimental stage. In the interior the cost of dredging unfrozen ground is 40 cents per cubic yard, while the dredging of frozen ground by thawing ahead of the dredge with steam points requires an expenditure of 40 cents additional. It will be recognized by those familiar with dredging that such a cost is prohibitive of the exploitation of the average dredging gravels.

River-bed gravels seldom average over 20 cents to the cubic yard in gold, locally enriched area from side tributaries necessarily being, excluded. It has been frequently stated by engineers that the average tenor of the Oroville gravels is not above 15 cents to the cubic yard. I see no reason to believe that the gravels cf the Alaska rivers, the Yukon, Tanana, Koyukuk, Kuskokwim, and their larger tributaries should be any higher. It is likely that only in very restricted areas will the tenor in gold of these streams be as high as 15 cents. It should be distinctly understood that Solomon River, Snake River, and streams of similar size in Seward Peninsula are not properly called dredging streams. They do not by any means fulfill the conditions implied in the foregoing geological description. While it is undeniable that in certain isolated cases streams having the character of Solomon River may be profitably dredged, the enterprise must be considered as lying outside the legitimate province of the golddredging industry as developed in California and New Zealand.

A recent study of the dredging fields of California has led to the conclusion that while dredging is possible to a greater depth than formerly (60 feet in Yuba River), there has been little reduction in the general costs of work. Eight cents per cubic yard is the lowest cost which may be safely counted on at Oroville, the principal field.

No special devices have been put into practice for breaking up cemented gravel, and some of the dredgers at Oroville are compelled to use powder to shake the bank in front of the dredge. Such practice would have no beneficial effect in handling frozen gravel. The use of hydraulic nozzles attached to the ladder frame at the lower tumbler seat has several times been suggested by engineers for assistance in thawing frozen gravel as the dredge operates." Experience in hydraulicking frozen bench gravels in Alaska has proved that such a device would be of no avail, since it is mainly the action of the sun and not that of the water which thaws the gravel face. The possible method of steam thawing is to drive long pipes from the surface into the ground ahead of the dredge (the practice in Bonanza Creek in 14-foot ground). The cost of this would probably be prohibitive when the depth of the ground exceeds 15 feet.

The onl}r manner in which heat can be applied directly to the part of the gravel face where the buckets are digging is by means of elec

Levat, E. D., L'Or en Siberie orientate.

160 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

trically heated water thrown against the bank. The fact that hydraulicking with water heated to 50° and applied directly to the face through a nozzle in Klondike drifting- operations is remarkably effective in thawing frozen gravel suggests possibilities in regard to dredging. This possibility is extremely remote, but might under certain circumstances be applicable where the dredge is operated by electric power generated by water under head.

The fact the dredge is the only appliance used in placer mining which transports its sluices and continually provides new room for its tailings renders it attractive in the consideration of the shallow northern placers.

In Seward Peninsula there are some river deposits which contain gold sporadically distributed and in which frozen and unfrozen areas alternate. Extensive prospecting has resulted in the discovery of a certain amount of ground which appears to warrant the installation of dredges of special design. More of these areas may be found, and I it is probable that some of them may be in the interior. It is not believed that dredges can be operated successfully in any of the area included in the South Coast provinces, as there the geological conditions are almost the exact opposite of those outlined at the beginning of this section.

Description Of Operations.

Notwithstanding the difficulties encountered in the interior of Alaska, the possibility of dredging in this field under certain favorable conditions is not to be denied. A small dredge for prospecting purposes was being operated cheaply in Stewart River in the Yukon Territory, not far from the international boundary, during the season of 1904. It subsequent operated in Klondike River. This dredge has 39 open connected 2i-foot buckets, and handles 750 cubic yards in twent}-four hours. It digs to 30 feet, and in Stewart River very little frozen gravel was encountered. A crew of 6 men is employed I and the daity working cost alone is said to be 7 cents a cubic yard. The hull was built at White Horse, of 4-inch planks of imported! Vancouver fir, and cost $5,000.

A complete description of this dredge has been published by the designer, Mr. A. W. Robinson."

A dredging installation was also visited on Gold Run, in the Atlin district of British Columbia. The power plant was situated on Pine Creek, 5 miles below the dredge. A flume and ditch line 1£ miles in length supplied 1,500 inches of water, at 187 feet head, to 2 Victor turbine wheels of 500 horsepower each. It was said that 80 per cent of this efficiency was available at the dredge. The current was delivered at 1,100 volts to the transformer and this was stepped up to

aThe Stewart River gold dredge: Canadian Mining Institute, March 4, 1903.

U. S. Geological Survey

BULLETIN NO. 263 PL. XXVill

A. Single-Lift Dredge, 40-Foot Ground At Atlin, Coarse Gold.

B. Buckets, Atlin Dredge.

purington.] DREDGING. 161

22,000 volts before its conduit over No. 6 copper wire 3-phase system to the dredge transformer, where a step-down to 500 volts was made. The turbines have 21-inch intake and 30-inch discharge, and the gates weigh 2j tons each. The water is available from April 1 to November 15. The power plant cost $50,000, not including an outlay of $10,000 for a 5-mile pole line, 3 copper wires, and 20 telephone wires.

The pole line was built by contract requiring that the poles should be 6 inches in diameter at top, 21 feet above and 5 feet below the ground, and that timber should be cut for a width of 10 feet, all at a cost of $2,250 for 7 miles.

A general view of the dredge is shown in PI. XXVIII, A. The cost, installed on the ground, was $200,000. It is of the close-connected, 3-foot bucket, single-lift type, arranged with trommel and pivoted sluice box, and tables carried on separate float. This type of dredge was considered necessary on account of the presence of coarse gold in the deposit. That by all dredging engineers the occurrence of coarse gold is not thought prohibitive of the use of the stacker dredge is apparent from Mr. Hutehins's remarks on this subject (see pp. 173-190). The arranging of the entire tail sluice to turn in an arc, operated by stern lines, permits the distribution of the dump. The system of digging is against a spud and not a headline. Operations had only begun when the dredge was visited; its estimated capacity is 2,500 cubic yards in twenty-four hours, digging to an average depth of 11 feet. The dredge is equipped with 5 motors, and a total of 200 horsepower is used. The total weight is 100 tons.

The hull was built in a pit on the ground, of Vancouver fir, and afterwards floated in the pond shown. It has a draft, loaded, of feet, !and is 90 by 36 feet in dimensions.

The winches are controlled by levers directly above in the pilot house on the starboard side of the upper deck. The 7 drums operate |ithe 1 side lines, main ladder line, and 2 spud lines.

The digging ladder is 90 feet long, 3 feet wide and 2 feet deep in the center, and is braced by steel trusses. The tumblers are of pentagonal form and of steel, with manganese steel plates riveted on, wTith ]8-inch shaft. There are 96 buckets that hold 3 cubic feet each, have [the shape shown in PI. XXVIII, B, and are equipped with manganese steel lips, pins, and bushings. As shown by PL XXVIII, A, a jbowlder weighing 1,500 pounds rode one of the buckets and was taken off on the upper deck. The buckets will dig 40 feet in front of the bow, and a bank 8 feet above water can be handled. The rate of wear jjm bucket lips had not been determined. A nozzle is used to clean the buckets as they pass the upper tumbler. No save-all is used. The pprocket wheels and chain are of steel, the diameter of the upperwheel being 10 feet. Bull. 263—05 11

162 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

The motors are of the following rated capacity:

Horsepower.

For digging 100

For 10-inch centrifugal pump 50

For 6-inch centrifugal pump 20

For screen 20

For raising ladder and operating lines 30

The gravel is raised 27 feet above the water. The trommel is 5 by 12 feet on 8 per cent grade, punched with holes that are inches in diameter in the upper plate, 7 inches in the middle plate (enlarged from smaller size), and 1-inch holes in the lower plate. Thirty-five per cent of the material is oversize and is dumped directly from the end of the trommel into 2 side chutes overboard. The trommel has 6-inch spray pipe, supplied by the 6-inch pump with water under 40 pounds pressure. It is estimated that the trommel plates will last one season.

From the trommel the undersize falls directly to a sluice connected by means of a pivoted box to the main sluice in the auxiliary float. This sluice is 4 feet wide, 120 feet long, and 2 feet deep, is of steel, has a grade of 8 per cent, and is provided with Oroville Hungarian riffles and grizzlies to allow the material to pass to undercurrent tables, which have an area of 1,000 square feet (see p. 195). The dump of the main sluice is 8 feet above the water. Two hundred pounds of quicksilver are kept in the sluice and tables.

The cost of dredging at this plant is estimated at 8 cents per cubic yard for the capacity above given, only actual labor, supplies, and superintendence on the ground considered.

A dredge of the New Zealand type was operating on Bonanza Creek in the Klondike district. It is shown in PI. XXIX, B. The boat had been in service for several years, having been first installed on Lewes River. It had then been towed and hauled by cables down Yukon River to the mouth of the Klondike and then taken apart and reerected on Bonanza Creek, where its operations have continued during the open months since July 1, 1903. A crew of 24 men operate the dredge and thaw the gravel in front of it. The thawing is done by means of 11-foot pieces of gas pipe, 12 in number, driven vertically into the ground. The bed rock here is a sericite-schist and the dredge is said to clean it well. The capacity of the dredge working under present conditions is 500 cubic yards in twenty-four hours, The bucket line is equipped with thirty 3i-foot buckets, open con nected. The ladder is 50 feet in length and will dig 28 feet below the surface of the water. At present the dredge is digging to a deptr of 14 feet and 8 feet in front of the bow. The stacking ladder carry ing a steel-bucket conveyor is 38 feet long, and carries all materia over inches in diameter, the size of the largest holes in the trommel, The lips of the digging buckets are of manganese steel and last foul

U. S. Geological Survfy

Bulletin No. 263 Pl

A. TROMMEL AND GOLD-SAVING TABLES, NEW ZEALAND TYPE, BONANZA CREEK, KLONDIKE.

B. New Zealand Dredge, Bonanza Creek, Klondike.

purington.] DREDGING. 163

months in use. New buckets cost $22 landed. The dredge digs on a 1-inch headline with five-eighths inch side lines, no spuds being used, and appeared to dig the gravel very satisfactorily after it was thawed. There is not over 2 per cent of the gravel which is over 18 inches in diameter. The hull is 71 by 30 feet in dimension and draws -1 feet of water; 55,000 feet of Oregon fir was used in its construction. The bow and ladder gauntrees are 15 feet high and are built of timbers 12 inches square. The dredge is operated by steam power. One vertical engine of 50 horsepower operates the dredge exclusive of the winches, which employ a separate 10- horsepower engine. The boiler carries 110 pounds of steam and in twent}-four hours burns 3 cords of native spruce wood, which costs $10 a cord. The winches are on the starboard bow side, the winchman's position being on the lower deck.

Since the trommel was built its length has been increased and is now about 15 feet, with T\-inch holes in the upper plate and 1-inch holes in the lower. The trommel was extended so that none of the nuggets, which are worth from $12 to $200, would be lost. The trommel distributes the fines to 8 tables, 12 by 30 inches in dimensions (see PI. XXIX, A), the distribution being regulated by iron gates. The tables, fitted with cocoa matting and expanded metal, have a grade of li inches to the foot, and are followed by 2 sluice boxes 20 feet long 2 feet wide, with angle-iron riffles, which discharge at the stern, as shown in the illustration. An inevitable difficulty with the dredge is the banking up of this material at the stern. Three thousand gallons of water per minute are pumped by a 10-inch centrifugal pump. The tables are cleaned up every day; sluices, once a month. The season for operating is from May 15 to October 1. It is understood that the dredge was successfully operated during the season of 1904 on ground which had been previously drifted.

The cost of the dredge laid down originally in Lewes River was

A shift sheet used in this dredge, devised by Mr. J. M. Elmer, is there appended and may be of interest to those engaged in or contemplating dredging operations.

Date,

Gravel And Placer Mining In Alaska.

Shift sheet of Lewes River Mining and Dredging Company.

[bull. 2(>3.

Number of shift, Winchman,

Lost time.

Ladder and bucket line

Stacker

Winches

Screen

Pumps

Lines

Clean ups

Oiling

Boiler

Condenser

Line shaft

Engine

Materials used.

Remarks.

Hours.

Minutes.

Character of ground,

. Total running time,

Total lost time,

Depth of ground, feet, Foreman, .

No dredging operations were in progress in the interior of Alaska during the summer of 1904.

In Seward Peninsula two dredges were operated in Solomon River and two land dredges were in operation in the vicinity of Nome, while another dredge was being constructed in Snake River near Nome, and a dredge was operating in a small way in Niukluk River, 1 mile above Council.

About one-fourth mile east of the town of Nome a small land dredge was operating on beach sand in the maritime strip. The section oi which the dredge operated was 12 feet in thickness, and consisted of 6 feet of beach sand, 4 feet of clay, 2 feet of gravel, and 2 feet of underlying broken .schist.

The dredge, which cost $5,500 in Seattle, was operated with a 6- horsepower gasoline engine. In addition, power was furnished to a centrifugal pump, which had the suction pipe led 60 feet out into the sea water. Eighteen gallons of gasoline, costing 40 cents a gallon, werei burned in ten hours. The dredge was mounted on trucks surmounted by a turntable, allowing it to turn on a circular track. The average capacity was said to be 200 cubic yards a day. This represents one of the many attempts which have been made to dredge the Nome beach sands, none of which, so far as known, have met with any success. This material is unfrozen, but many difficulties are encountered. Storms which render the beach uninhabitable are causes of long delay, and the attempt to pump the sea water is a cause of constant trouble on account of the seaweed and wreckage which cloo-s the screen.

PtmiNGTON.] DREDGING. 165

A small land dredge running on a 40-foot track, and digging a canal beneath for the purpose of Laying a long bed-rock drain, was operating on Bourbon Creek, one-fourth mile north of Nome, The work was in an experimental stage, and a large dredge of tin1 same type, of 500 cubic yards daily capacity, was under construction.

A floating dredge of the dipper type, with sluices arranged on a separate hull, was under construction in Snake River, one-half mile from Nome, but the data relating to it are not available for publication.

A small bucket dredger so arranged that the digging ladder can turn through an angle of 20° has been operating in Solomon River, 3 miles north from the coast for the last two seasons.

In the operations of 1903 a 60-foot width of the channel of Solomon River was worked and was found to be unfrozen; the gravel averaged 5 feet in thickness and rested on schist bed rock. The tenor is said to have been $1.13 per cubic yard. The greatest thickness encountered from the surface of water to bed rock was 12 feet. One and one-half feet of the schist bed rock was taken up by the dredge. The bed rock is generally soft, but has hard reefs. The largest stones found were 1 foot in diameter. The dredge was operated by 5 men on 2 shifts, the amount of running time being from twelve to twenty hours out of the twenty-four. The men are said to have made a profit, paying a royal} of 25 per cent on the output. The dredge is of 16- horsepower capacity and handles an average of 150 cubic yards in twenty -four hours. The operations consume two to three cases of gasoline a day, the average for fuel being $12.50. The total expense is figured at $30 a day. The experience with the pay is that the ground is very spotted, being in places rich and in places barren. There are 32 buckets of 1 cubic foot capacity- on the ladder. A cut of 30 feet across is made in one setting. The ladder is made of 1-inch cast-iron pipe and can be lengthened by adding pipe and buckets. In 11)01 the dredge was being operated lyy 2 men on a shift, one man running the winches, and one man attending to the engine and picking out the large bowlders and throwing them overboard. The bucket lips are made of tool steel.

The sluices into which the buckets dump directly are fitted with punched-iron screen of the ''Caribou11 pattern, described elsewhere, followed by Hungarian riflles. The sluice is feet in length, 23 inches wide, and 12 inches deep, with a grade of 15 inches in 12 feet. The end of the sluice is 3 feet above the deck, and extends 6 feet beyond the end of the boat. Quicksilver is used in the upper box es. Seventy-five per cent of the gold is caught in the first 6 feet, and the balance in the next 8 feet. The tailings are frequently panned, but no gold found.

The description of this dredge, the cost of which should not exceed $25,000, laid down, is given in detail, as it is reported on good author-

166 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

ity to have been successful in its operations. It presents a strong confirmation of the views expressed by Mr. Hutchins concerning the advisability of installing prospecting dredges for Alaska practice.

During the season of 1903 and 1904 a dredge of the dipper t}7pe was operated in Solomon River, near the one above described. The dredge was constructed originally with a stacker, but this system was abandoned and a separate hull was built on which a hopper and sluice were erected.

The dredge cost $33,000 on the ground, and weighs, barges and all, 400 tons. It is equipped with one yard dipper, which digs three-fourths cubic yard of material each time on an average. During 1904 the dredge was in operation fifty days of twenty hours each, and handled 21,000 cubic yards, or an average of 420 cubic yards a day.

The ground dredged is 9J feet in average depth, and was all handled by the dipper. No permanent frost was found in the river bed, but the annual frost did not leave the ground until July 15, delaying the commencement of operations until that date. Thirty days at the end of the season were lost on account of the breaking of the main cable operating the dipper, and there was no chance to repair it.

The experiences with the ground in this dredging operation were especially interesting. It was found that in places the gravel in the river itself was frozen all summer. On July 20 there were 7 inches in depth of frost within 2 feet of the surface. This disappeared with the first heavy rain. The dipper cleaned the bed rock successfully where it was black schist. Where the bed rock was limestone the ground was drifted in the winter with much more satisfactory results than the dredging gave.

The dredge employed in the two shifts seven men, at $7 a day, and one man, at $9.50 a without board. In twenty hours 3 tons of coal, costing $26 per ton, were consumed.

The cost of dredging in 1904, including repairs to and maintenance of plant, was 50 cents per cubic yard. As in the case of the small dredge, the pay over a width of 200 feet, which was worked in places, was found to be spotted, varying from 30 cents to $12 to the cubic yard.

It is said that the clay in the gravel prevented the water from sluicing gold from the bottom of the dipper, and tests showed that a saving of 95 per cent was made. The sluice was paved with Hungarian riffles, and quicksilver was used.

The general opinion expressed by these operators was that dredges having a capacit} of not to exceed 1,000 cubic yards daily will pay in Solomon and similar rivers of Seward Peninsula if operated by electricity generated from a central water-power plant. The employment of gravity-sluicing water was made a necessary condition. While

purikgton.] DREDGING. 1()7

this is possible, it should be borne in mind that the employment of gravity- sluicing water on a dredge entails numerous and largely untried difficulties.

Some of the special difficulties actually experienced in the operations above described were distance from any repair shop, sudden rises of the river after two da}7s' storm that prevented persons from crossing and endangered the dredge, and repairs which were necessary at the beginning of the season, and which included chopping ice out of the inside of the hull.

The dredge shown on PL XXX, B, in Niukluk River, was operating only in prospecting work during the season of 1904:. It has 5-foot buckets, open connected. Its rated capacity is 2,000 cubic yards in twenty-four hours, but the actual capacity can not be given. The dredge was fitted with a rubber belt conveyor for the stacker. This is said to give much trouble, as when it begins to freeze at night in September the belt continually slips. It was said that in previous operations the dredge in ten hours used 5 cords of spruce wood, costing $12 a cord, and handled 800 cubic yards of material. Eight men were employed at $7 a day, gross. In the Niukluk River banks the bed rock, which is schistose limestone, is 10£ feet below the surface, and is overlain by 1 foot of moss or willow roots, 2- feet of sand or muck, and 7 feet of rounded river wash mixed with angular limestone fragments. Willows grow on the unfrozen ground and moss covers the solidly frozen ground. No regularity in the distribution of the two is apparent.

The success of dredging operations in the Niukluk appears to be extremely problematical. So far as the physical nature of the gravel goes, no difficulty should be experienced. Frozen areas, hard bed rock, uneven depth, and irregular distribution of the alluvial gold are, however, serious if not insurmountable obstacles to the success of a dredging operation which in a superficial examination of the ground may appear attractive.

Cost Of Dredging.

It is manifestly impossible to give detailed statements of operating expenses in a work of this character, especially when dredging has been conducted in a desultory fashion and for a limited period. The costs given on page 38 include a certain amount each year for the amortization of the plant and the ground. Bearing this in mind, those having the slightest familiarity with the subject will probably admit that the figures, namely, 49 cents per cubic yard for unfrozen, 80 cents for frozen ground in interior Alaska, and -13 cents per cubic yard for Seward Peninsula, are not excessive.

For purposes of comparison there is given the following statement of the cost at Oroville, Gal., quoted in the Mining and Scientific Press, February IS, 1905, from the report of the Oroville Dredging and

Gravel And Placer Mining In Alaska,

[Bull. 263.

Exploration Company to the stockholders for the year ending December 31, 1904, by F. W. Bradley, president. The figures given represent merely operating expenses, and do not include allowance for depreciation of the plants and of the ground. It should be remembered, however, that even adding these items of expense to the operating cost per cubic yard the number of yards handled per season is so large, as compared with that possible in northern operations, that the total California cost is not greatly increased. Eight cents per cubic yard is believed to be a safe estimate for the present total cost of gold dredging at Oroville.

The table of lost time in the following quotation is especially interesting1 as showing: that even under the favorable California conditions the actual dredging time of a presumably representative dredge amounted to only 67.2 per cent of the whole.

Dredging At Oroville, Cal.

Our No. 1, or $45,000 dredge, made the following record: Cubic yards dredged

493, 150

Gold yield per cubic yard, $0.1232; operating costs, $0.0562; operating profit, $0,067, or $32, 905. 7S

Improvement, taxes, insurance, legal, and all other working expenses

(except construction of No. 2 dredge) 7, 166.

Surplus 25, 738. 91

Our No. 2, or $75,000 dredge, should be ready to begin work next month (January, 1905). Figuring on the data now available, the two dredges should make the fol lowing average annual record:

Dredge No. 1 (first cost $45,000) Dredge No. 2 (first cost $75,000)

Total or average

Improvements, taxes, and all other working expenses

Total

Dredged.

( 'ubic yards. 520, 000 780, 000

1,300,000

Operatingcost.

Per cu. yd'.

$0. 0530

Probable yield.

Percu. yd.

$0. 095

Surplus.

$0. 035

Or a yearly surplus of $45,500. Our prospect information indicates that after rejecting that portion of our land of doubtful value the property should have a life of from thirteen to fourteen years at the above estimated rate of dredging.

C. H. Munro, superintendent, makes a detailed report of the company's (iterations, from which the following is taken:

Extraction. — The prospect value of the area dredged, based on the average value of the holes in and near the dredged area, was 16.64 cents. The extraction table herewith attached, which is computed on these figures, makes the extraction 74 per cent of the prospect value.

The extraction amounted to 76.37 per cent of the prospect value, based on the proportional or fractional areas as influenced by each prospect hole.

U. S. Geological Surve1

Bulletin No. 263 Pl

A. Dredge Of New Zealand Type At Oroville, Cal, Leggett No. 3.

B. Buckets, Dredge At Council.

Pueington.]

Dkkduino.

It would therefore be fair to call the extraction 75. IS per cent of the prospect value, which is the average of the two methods of computation above referred to.

During the year just ended, Biggs No. 1 dredged LI. 85 acres, handling 493, 150 cubic- yards, which yielded a gross bullion return of $60,738.52, or an average yield of 12.32 cents per cubic yard, as compared with a gross bullion return of f>36,525.25, or an average yield of 8.45 cents per cubic yard for 1908.

Costs. — The operating cost has been 5.62 cents per cubic yard, and the total cost, including all improvements, repairs, taxes, insurance, legal, office, and other expenses (excepting Biggs No. 2 construction account), has amounted to 7.06 cents per cubic yard.

Comparing the capacity of the dredge and the cost of operation for 1904 with 1903, the capacity has increased from 39,551 cubic yards per month to 41,090 cubic yards per month, while the cost of operation has decreased from 6.48 cents per cubic yard to 5.62 cents per cubic yard, and the total expense from 7.71 cents to 7.06 cents per cubic yard.

The bullion yield has increased from 8.45 cents per cubic yard to 12.32 cents per cubic yard.

Repairs. — Aside from the ordinary repairs on the dredge, a new revolving screen was installed at a cost of $1,600, and the 1-horsepower motor used for priming the water pumps and cleaning up was replaced by a 3-horsepower motor at a cost of

$1:

)5.

Flame repairs. — During the floods last February 500 feet of the flume and trestle were washed away. The rebuilding of the flume and trestle and repairs at the pump station cost $357.40.

Improvements. — The blacksmith shop equipment has been enlarged at a cost of $547.45 by installing a 5-horsepower motor, with transformer, a forge, blower, emery wheels, grindstone, and small drill press.

Biggs No. 2 construction. — The hull of Biggs No. 2 is completed and the dredge was floated the first of the year. The contractors are now installing the machinery, and the dredge will probably be ready for operation about the middle of February, 1905.

Bullion table.

Month.

January . . . February . .

March

April

May

June

July

August

September October

November. December .

Cubic yards bank measurement dredged.

Total oraver-

20,840 32, 000 41,160 50, 760 47, 700 40, 750 44, 880 89, 800 41,600 48, 460 40,300

46,400

Bullion yield.

493, 150

$3, 120. 87

3, 408. 59

7, 732. 02 9, 600. 10

8, 072. 1 7 3,704.36 4,271.03 4,27.°.. 81

4, 265. 74 4, 645. Os

3, 874. 92

4, 269. 73

60, 738. 52

Operating expenses.

Yield per cubic yard.

Operating

cost per

cubic

yard.

$2, 077. 00 2,418.94

1 , 854. 69

2, 238. 4 1 2,013.97 2, 272. 30 2,471.91 2,392.09 2, 620. S3 2,340.96 2,831.31

'nils.

Is. 91 10.2") S. 37

Ct tits.

5. Ss

5. Si

27,832.5:;

Operating profit peicubic yard.

Ct uls 2,

(i. 70

Gravel And Placer Mining In Alaska,

Extraction table.

[bull. 263.

Month.

Dredged.

T3 3

Q

as

3 oj

O

So cd

a

0)

o .

O

U "

Ox!

k,3

go,

Character of ground dredged.

January

February

March

April

May

June

July

August

September

October

November

December

Total or average..

'Ik

20, 340 32, 000

41,160 50, 760

47,700 40, 750

44, 380

39, 300

41,600 48, 460

40, 300

46, 400

Cts.

Per cent.

493, 150

Coarse gravel to surface; dredging across slough.

10 feet top soil; 2 feet of grave1 on bed rock; hard digging.

10 feet soil ; gravel coarse, and hard digging.

12 feet top soil; 15 feet coarse gravel; 3 feet on bed rock; hard digging.

12 feet top soil; gravel coarse.

10 feet soil; gravel firm, and sand on north side of cut.

4 feet top soil; coarse gravel on west side cut; sand streak on eastside.

6 feet top soil; sand streak on west side of cut; all fine gravel; easv digging.

6 feet top soil; sand on west side of cut; all fine gravel; easy digging.

6 feet top soil; sand in center of cut; remainder fine gravel; easy digging.

7 feet top soil ; east side cut in sand; remainder of cut fine, and coarse gravel.

7 feet top soil; coarse and fine gravel full width of cut.

Dredging.

The figures for the several items of expense in the following tables varied from month to month throughout the year, and the averages for the entire year only are given:

Operating and all other costs.

Operating expense Biggs No. 1 and superintendence

General expense, Oroville and San Francisco

General plant

Bullion expense

Taxes

Warehouse

Insurance

Legal

Total

Total for year.

Total expense per cubic yard.

Cents.

$27, 832. 53

1, 788. 62

1, 262. 78

1,942.66

1, 070. 50

34, 999. 41

'.06

Details of operating costs.

Labor:

Operative

Repair

Superintendence

Power:

Dredge

Pumps

Hardware:

Supplies, tools, oils, etc

-.Repair parts, etc

Freight, express, and hauling

Steel cables

Lumber

Electric supplies and work...

Clearing ground

Sundry expenses

Total

Total for year.

$6, 435. 20 4, 690. 41 1 , 875. 00

4, 902. 81

1,109.77

6, 768. 23

27, 832. 53

Per cent of total.

Per cent.

Cost per cubic yard.

Cents.

172 GRAVEL AND PLACER MINING IN ALASKA. [bull.263.

Repair table showing cost of labor and material on different parts of the dredge.

Total for year.

Grand total.

Ladder:

Labor

$492. 63

1,328.07 3, 237. 35

1, 125. 04

1,498.57

31 1. So

1,307.59

Material

$1 , 089. 06

Bucket line:

Labor

Material

4, 565. 42

Stacker:

Labor .

Material

2, 019. 70

Winches:

Labor

Material

Screen :

Labor

Material „

2, 220. 99

Pumps:

Labor .'

Material

Power:

Materia 1 .

Lines:

Labor

Material

Gold tables and clean-ups:

Labor

Material

226, 74

( lontingent repairs:

Labor

Material

2,108.15

Table of lost time.

Ladder per cent. .

Bucket line do. . .

Winches

Screen

.do. .do. .do.

Pumps ;

Power.. do.

Lines ta do.

Clean-up do .

Other causes do .

pip.iN.ToN.] DREDGING. 173

Total lost time per cent. . 32. 8

Dredging time do 67. 2

Average number of cubic yards dredged per day of running time 2, 005

Actual average number of cubic yards dredged per day of twenty-four hours. . 1, 347

Summary of costs in cents per cubic yard, 1904.

Dredge crew and power 2. 69

Repair labor 94

Repair supplies 1 . 61

Superintendence 38

Oroville and San Francisco general expense 36

Taxes and insurance 48

Bui lion expense 05

Grand total, all costs 6. 51

For three $45,000 dredges these items would have been as follows:

Dredge crew and power 2. 69

Repair labor 66

Repair supplies 1. 61

Superintendence ...'. 17

Oroville and San Francisco general expense 12

Taxes and insurance 27

Bullion expense 05

Grand total, all costs 5. 57

Mr. J. P. Hutehins, of San Francisco, who has had long experience in the dredging fields of Oroville and has recently worked in the Klondike, has courteously furnished for this report an account of the present status of the industry, with suggestions regarding the forms of dredges most applicable to Alaska conditions.

Notes On Dredging.

By J. P. Hutchins.

Dredge mining of placer gold has been one of the most attractive fields for investments of capital in recent }Tears. Prospecting methods in use to determine the values of the areas thought to be available for profitable exploitation by dredging are not complicated. Until recently well-drilling machines have been used almost exclusively in this work, and in many cases the results of such sampling have led to large investments of capital in dredging ground and dredging machinery; These drilling machines have much to recommend them. They are cheap and mobile, can be operated on floating scows to sample river, lake, or sea bottoms (see PL III, J., p. 40), or used to sample a deposit where a large volume of water near the surface would make shaft sinking very costly. Numerous holes can be drilled in a short time and at a comparatively small cost. In many cases shafts have been sunk with the drill holes for centers, and the results of the two methods of prospecting checked well.

It was first held that the results of dredging could be relied upon to equal about 50 per cent of what drill prospecting would indicate the

174 GEAVEL AND PLACER MINING IN ALASKA. [bull. 263.

values to be. The disparities were in part accounted for by attributing them to spilling, leakage, faulty discharge of buckets, incomplete excavation apparatus, incomplete disintegration during washing in screening, and to losses in the gold-saving apparatus. It seemed, however, as if these losses should be only about 10 per cent, and the other 40 per cent was explained by the well-known general statement that "prospecting results are always high."

Up to the time that considerable areas previously prospected with numerous drill holes were dredged, the results of drill prospecting were believed to be absolutely reliable, making the allowance, however, of about 50 per cent for values to be recovered by the dredge. After these areas had been worked, however, the dredge managers found much to surprise them, for where ground had prospected well it had dredged poorly, and vice versa. It is asserted that in these instances both the drilling and dredging were so conducted that no great reliability could be attached to the results, but this explanation is far from satisfactory.

In the use of the drilling machine to sample alluvion, as in all other prospecting, unusual care must be exercised to obtain results that shall give a correct idea of the values and of the other characteristics of the ground under examination. It is unquestionably true that careless sampling has been the cause of many failures in dredging operations. The seeming simplicity of this prospecting method has, as in other apparently simple determinations, resulted in crude manipulation and misleading results. In some instances there has been a misleading affectation of accuracy in tabulating results of drill prospecting. Careless location and distribution of drill holes have given faulty results. Nevertheless, the percussion drilling machine is peerless for testing most areas that may be available for exploitation by the dredging method.

The drilling machines are used for several purposes. It is necessary to determine whether the material is too hard to make dredging profitable, and for this purpose drilling machines are not entirely satisfactory. In several areas prospected ))y drilling machines and thought suitable for dredges the material proved to be so hard that a machine different from the one designed was required for successful exploitation. Jf the prospecting had been done with more care this unfavorable condition would have been learned.

Reliable results call for the determination of the presence and distribution in the vertical section of any considerable content of tenacious clay and large bowlders, and here again the drill does not yield entirely satisfactory results. The depth of material must be ascertained and, where the bed rock is a so-called "false," the greatest care is necessary in order to determine its position. The character, hardness, and roughness of the bed rock must be learned, and the drill unfortunately

purington.] DREDGING. 175

still leaves much to be desired in connection with this phase of the investigation. In spite of these drawbacks the percussion drilling machine has no superior as a preliminary means of prospecting alluvions thought to be suitable for working by the dredging method, and this is particularly true where large volumes of water may be encountered near the surface. The sinking of shafts is to be preferred, however, where not too costly.

In several projects, where a large expenditure of money is in contemplation, so-called prospecting dredges have been used. These machines are small but complete dredges, and perform, on a small scale, the functions of the ordinary type. Their design is such that the}7 may be readily moved, for they are equipped with lightly constructed machinery and hulls and are of light draft. If, as is frequently the case, the area to be prospected is traversed by a river or sloughs, such a light dredge is easily moved from place to place. Where there are no waterways, a still smaller dredge, to be moved on rollers or skids, can be employed.

Though the cost of installation and operation of such prospecting dredges is considerably more than that of drilling machines, the reliability of the results will often justify the additional expenditures, particularly where large areas are being prospected. By their use the values per cubic yard, character of material, presence of large bowlders and clay, and depth and character of bed rock can be accurately ascertained. There is an additional advantage of great importance in the fact that the cost of operating a large dredge can at the same time be closely determined.

The number of gold dredges in successful operation in the United States has greatly increased during the past decade, and especially in the last six years. The first successful one was operated at Bannock, in Montana, and was of the so-called "double-lift " type. The material was excavated by a chain of buckets and discharged from an elevation of about 15 feet above the deck into a trommel, which had perforations about 5 inches in diameter. Stones of larger diameter were discharged over the side of the dredge; the " lines" were elevated by a 12-inch centrifrugal dredging pump to a sluice and discharged about 100 feet astern. This type of dredge is still advocated by some managers, and unquestionably has a number of advantages over other types. It is especially good for handling material which has a clay content or which is so tenacious that gold is lost by incomplete disintegration and insufficient washing in the screens and sluices of the other types of gold dredges. The passage of the tines through the centrifugal pump of the double-lift dredge tends to disintegrate the material thoroughly and to completely liberate any particles of gold held in clay or other tenacious substances.

176 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

The particular problem at Bannock was to evolve a dredging pump to stand the wear and tear of handling the fines of about 2,000 cubic yards every twenty -four hours. The first pump was worn out after seventy hours' use, but another of excellent construction, designed by the dredge manager, was installed and used for several years. After a seven months' run, when the fines of over 400,000 cubic yards had passed through it, it was estimated that the costs of repairs and renewals of the pump had been only* about $150.

With a view of eliminating the dredging pump the so-called singlelift dredge was designed by Montana men. This type discharges the material about 28 feet above the deck into a trommel with perforations 5 inches in diameter. As in the "double-lift" dredge, the coarse material was deposited over the side, while the fines dropped into a sluice and were discharged about 100 feet astern. The greater height of discharge of buckets made a secondary lift of the fines unnecessary. This form of construction introduced a new set of problems, as the higher position of the upper tumbler necessitated longer ladders, more and heavier buckets in a longer bucket chain, larger hulls, and heavier construction throughout. Some of the first u single-lift" dredges were very unstable because of the high position of center of gravity. This type of dredge is now in more general use than the " double-lift" machines.

The dredge which had been used so successfully in New Zealand was not introduced into the United States until after the extensive operation of these two types. The first New Zealand dredge was installed in the Oroville district of California, and after a few modifications to suit. local conditions was and is still operated successfully. This was followed by the building of a number of similar dredges in; California, Colorado, Idaho, Oregon, Montana, and elsewhere (see Pis. XXX, A, and XXXI, B).

These dredges were essentially different in design and manipulation from those of the double and single lift types. While the bucket of the New Zealand was evolved entirely for gold-dredging purposes, the bucket previously used in this country was but a slight modification of the one used for harbor and canal dredging. In both t}rpes, but more notably in the bucket evolved in harbor and canal dredging, the first made were deficient in the strength of the digging apparatus.

The New Zealand t}rpe of gold dredge discharges the material about 16 feet above the deck into a trommel, the largest perforations of which are about one-half inch in diameter. A stacker (see PI. XXXI, B) made of a chain of steel buckets elevates all material not passing through perforations of trommel and discharges it astern of the dredge at a height sufficient to allow for the expansion of the tailings. The fines pass over the gold-saving devices and are dis-

U. S. Geological Survey

Bullftin No.

Pl. Xxxi

ft

fit

A. Digging On Spud.

B. Stacker, New Zealand Type Of Dredge. California No. 1.

Iurington.] DREDGING. 177

charged about 10 to 15 feet astern of the dredge. On the double and single lift dredges no stackers were necessary, because the larger perforations of the trommels allowed the comparatively small percentage of- stones to be discharged over the side without shoaling the water too much.

The gold-saving apparatus introduced with the New Zealand type was also essentially different. The hydraulic mining undercurrent, which is a wide sluice with steep grade, and which spreads the material over a broad surface in a shallow sheet after all stones of diameter greater than 2 inches have been removed by a grizzly, was evolved in California but had been successfully used in New Zealand in hydraulic operations. A very slightly modified form of this device was used on a number of the dredges, with the difference that cocoa matting instead of riffles charged with quicksilver was used to catch the gold (see PL XXIX, A, p. 162).

The double and single lift gold dredges depended principally, and in some cases entirely, on a comparatively narrow sluice with riffles charged with quicksilver. The material passed over the riffles in a deep sheet, a condition not conducive to a high percentage of saving, where the gold is in the form of very finely divided particles.

"There is a. marked difference in the manipulation of the several types of dredges. The New Zealand boat in digging is held to the face of the bank by a headline run out over the bow to an anchorage, and the buckets are lowered in a vertical plane, the material beingcaved by undermining at the bottom. The other types are held to the face by a pivotal stern spud (see PI. XXXI, J.), the buckets beingside fed horizontally through an arc of 120°. The cut is begun at the surface and the digging ladder lowered about 1 foot at the completion of each arc, no attempt being made to undermine or cave the material excavated.

Several shovel dredges were built at Oroville at about the time the New Zealand type was installed. On these the hydraulic-mining undercurrent, almost the same as that of the hydraulic miner in California, and a shaking screen, similar in action to the rocker of the early-da}T California miner, are used. Belt stackers were also installed. The shovel dredges proved costly of operation and have, with few exceptions, been discarded.

Next in order of development came a dredge with the bucket evolved in canal and harbor dredging. The machine was very much strengthened, however, and was provided with shaking screen, belt stacker, and hydraulic-mining undercurrents, called " gold-saving tables." In this type is found a combination of the belter features of the double and single lift and shovel gold dredges. Small buckets were first used, but the tendency}7 had been toward increased capacity. This dredge was an improvement, but it had a fault common to all the Bull. 263—05 12

178 GRAVEL AND PLACER MINING IN ALASKA. |bull. 263.

dredges at that time and still often found — a lack of coordination of capacity in the four processes of which gold dredging consists, namely, excavating, screening, sluicing, and tailing.

The next improvement was the building of a dredge in which coordination of capacities received more attention, for in this the screens, tables, stacker, and pumps were enlarged. It was designed to work either on spud or headline, with a slightly higher discharge of material to permit of a greater elevation of coarse tailings and a stacking of them at a distance from the stern. The pivotal spud was placed inboard so as to make the digging and the tailing arcs of more equal lengths when working on a spud. The difficulties encountered when these arcs were of very unequal length were thus eliminated. The disposition of the tailings had formerly been a continual source of difficulty and expense, but this improved dredge was so designed as to allow both working on a headline and side feeding through an arc of long radius. This permitted the working of a wide cut and the disposition of tailings without covering adjacent virgin ground, for previously much untouched territory had been wasted being covered with tailings. Impact riffles charged with mercury, i. e., those where the fines are dropped to effect amalgamation, and larger gold-saving areas were also introduced.

There have been no radical changes in the design or construction of gold-dredging machinery of late, and efforts have been directed toward the strengthening and bettering of machinery and hull and the lowering of operating expenses.

The excavating apparatus (see PL XXXII; PL XXVIII, B, p. 160, and PL XXX, B, p. 168) used in gold dredging has been very much improved since the first installations. Bucket forms have been modified so as to prevent losses by spilling. This is accomplished by reducing the angle made by the bucket lip with the line through the centers of the two bucket pins. With the earlier design a considerable loss by spilling, except when buckets were working at maximum depth, was noticed. In the earlier design the bucket was long, narrow, and deep, and a clean discharge was not effected, especially when working in sticky or sandy material. Recent design provides a short, wide, and shallow bucket which discharges more perfectly. The use of jets of water to wash any adhering material from both inside and outside of buckets into the hopper and save-alls is now common and accomplishes a considerable increase in the gold saving. The capacity of buckets has been largely increased, but the economical limit has not been reached nor will it be reached in the near future.

With the increase of size of buckets there has not been a proportionately greater strength, but this defect is being gradually remedied. The use of various alloys of steel in bucket parts, as well as in other

U. S. Geological Survey

Bulletin No. 263 Pl.

BUCKETS. A, California No. 3; B, El Oro; C, Indiana; I), Lava Beds No. 2.

Dked(In(J.

parts of the dredging machinery where there is severe wear and tear, has been in most eases successful.

The design of the upper and lower tumblers has been modi lied and all parts subject to wear are now easily replaceable. In earlier installations the tumblers were of such design and construction that the wearing out of one part sometimes necessitated the loss of the whole. Some trouble has been caused by the working loose of the " wearing plates." Tumblers with more numerous faces are now also used. In early practice the square upper tumbler was supposed to be superior to the one with more faces, it being assumed that the square tumbler was more capable of firmly holding the buckets and preventing the danger of its revolving without moving the bucket chain. The hexagonal upper tumbler is now in successful operation, and it is safe to predict that heptagonal and possibly octagonal upper tumblers will be

Fig. 34.— Angles for upper tumbler.

used, particularly on the smaller dredges. The objection that they will not hold is not good. Even if true, an arrangement making the i relation of bucket to tumbler that of chain to sprocket would solve the difficulty. The use of the heptagonal and octagonal upper tumblers introduces a new set of problems, involving larger tumblers and shaft ing, different arrangement of chute to hopper, and modified forms of save-alls. These modifications are necessary because of the resulting longer period of discharge of the bucket. It is probable, however, that saving in wear of the bucket pins and bushings due to lesser deflection in turning tumblers of more numerous faces will compensate for the extra expense involved in construction.

Fig. 34, above, shows the relative size and different deflection angles made by the buckets in turning the square, pentagonal, hexagonal,

180 GRAVEL AND PLACER MINING IN ALASKA. [bull. 26:

heptagonal, and octagonal tumblers and per cent of saving of vvea over the square type. The wear and tear of bucket pins and bush ings is almost entirely the result of the deflection of the buckets i rounding the tumblers. A slight amount of wear is occasioned b deflections back of the lower tumbler as the buckets come in contac with the material. These last deflections, however, would be prevent by rollers such as are suggested in a paragraph on page 184 discussing. the respective merits of the spud and headline.

If, instead of square upper and lower tumblers, pentagonal, hexagc nal, heptagonal, or octagonal tumblers are used the saving of wear o bucket pins and bushings would be approximately 40, 66, 86, and 10 per cent, respectively.

There is but one serious objection to the use of a lower tumbler o more numerous faces, i. e., greater size and weight. The great savin in wear of the bucket pins and bushings will, when fully appreciated result in the use of both upper and lower tumblers of more numerou I faces. (See PL XXXIII, .4.)

One dredge manager of much experience has suggested the use o a round lower tumbler of large diameter with buckets of short pitch claiming that buckets seldom lie flat on tumbler faces when excavat ing, but frequently ride the corners between the faces. This difficult; ; has been observed by the writer on many Occasions. A too rapi . feeding of buckets resulted in considerable spilling of material upo. the buckets about to round the lower tumbler. The spilled materia; lodged between the buckets and the tumbler faces and destroyed, tern porarily, their proper relation. The use of the round lower tumble would have the additional advantage of preventing surging (se p. 184).

Until recently it has not- been generally regarded as good practic to lower the digging ladder to more than 45° from the horizonta because of supposed disadvantages in such manipulation. Recen : installations provide an idler at the rear end of the well to preven the buckets from dragging on the chutes and the save-all gratings a the ladder is lowered more than 45° from horizontal. This devic permits greater working depths with a given length of ladder am makes deeper ground available for the dredge. PI. XXXIII, B illustrates diggings at a low angle. There is a marked diversity opinion among managers as to the relative merits of the trommel am shaking screen. The trommel advocates have claimed better mechan ism, cheaper maintenance, more efficient screening when material is a all tenacious, and economy in power. The advocates of the shaking screen have claimed larger capacity with given weight, higher per centage of gold saving because of better opportunities for amalgama tion by impact, and easier and better distribution of material over th< gold-saving surfaces.

U. S. Geological Survey

Ul/.Etin No. 263 Pl. Xxxiii

A. Lower Tumbler, California No. 3.

B. Digging Ladder At Low Angle, Oroville, Cal.

ITKlNGTON.j DK EDGING. 181

The trommel (sec PI. XXIX. J, p. 162) is a better mechanism, requires less power for operation, and gives much less trouble in maintenance than the shaking screen and does cleaner screening, particularly when the material is at all indurated or tenacious. Trommels have almost without exception been too small, and all late installations are larger. Amalgamation by impact is now accomplished by a special arrangement of the gold-saving apparatus, and distribution of water is no longer a difficult problem on dredges where trommels are used. One of the most recent installations by a company which has extensively employed both devices includes a trommel. At present in most cases the trommel is in high favor among Oroville operators.

Where there is an overburden of any considerable depth the use of a device to blank the trommel or screen will be a distinct improvement. By its use all barren material can be stacked well back of dredge and usually at a more rapid rate than if handled in the ordinary way. Overburdens, which it is always necessary to dispose of as quickly and cheaply as possible, usually consist of a fine loam or sand which can be run but slowly over the gold-saving devices because of clogging when handled rapidly. A blanking device was used for a time at Oroville and worked well, but, because of bad design, required too much time in blanking and unblanking the screen. Its use, however, allowed the beginning of dredging operations, on interior ground, without the use of a sand pump and the immediate excavation to a depth of 30 feet, with a consequent minimum wasting of dredging ground. The use of such a device involves a large discharge of material from screen or trommel to the stacker where a troughed belt is used. The incline of the stacker must not be so steep as to permit the material, which is often a thin mud, to run back to the end.

The use of a device to blank the hopper which shunts the material into the well has been tried, but has not been entirely successful. In this case also, bad design rather than bad principle was responsible for failure. The disposition of an overburden by this method is to be heartily recommended, especially where dredges work on headlines, as they are thus enabled to distribute the barren material across most of the width of the cut.

The gold-saving apparatus, after many experimental modifications, including the introduction of various magnetic and intricate devices, has returned to the hydraulic-undercurrent type with the mercury riffle. For saving clean gold the mercury riffle is probably best. When, however, for &ny reason there is imperfect amalgamation, the use of some form of woven material to enmesh particles of rusty gold is good practice.

The increase of the area of gold-saving surface has met with good results. Steeper grades are now used for gold-saving tables than for

182 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

merly, and arrangements are such as to allow a better distribution ol sluicing water to various parts of the gold-saving areas. Gold-savinc surfaces are now generally arranged in a number of drops, and th< material impinges upon riffles charged with mercury and is amalgamated by impact.

Much thought has been recently given to the perfecting of save -alls, and a surprisingly large amount of gold, sometimes 10 per cent of all saved, is recovered in this way. The design of save-alls in the earlier practice was somewhat neglected, but in the general refinement of working methods a considerable improvement is being effected. A device for keeping under lock and key parts of the gold-saving apparatus where the largest proportion of gold is caught has been introduced.

The t roughed belt stacker seems to be generally regarded as superior to the bucket stacker (see PI. XXXIV, B) because of greater economy of operation and less weight for a given length. Stacker belts are a source of large expenditure because of the rapid wear due to the insufficient thickness and inferior quality of the material which covers the woven part of belt and which gives the belt its wearing qualities.

Nearly all the recently installed stackers have the driving pulley on the outboard end, and electric dredges have the driving motor, as well, on the outboard end. (See PI. XXXIV, A.) This arrangement has eliminated a number of troublesome features. If the stacker isj driven by rope or sprocket chain from a motor on the dredge, there is much trouble due to wear, slipping, and stretching of ropes and of sprocket chains. If the driving pulley is at the inboard end of the stacker, the load is pushed uphill on the slack side of the belt, and there is much trouble from slipping and stalling. A belt stacker driven the inboard pulley requires more power than one operated by the outboard pulley.

At one time it was generally thought that when coarse gold occurred in the material dredged, either the double or single lift type of dredge must be used. Stacker dredges are now used and have at the lower end of the trommel perforations large enough to pass material up to H inches in diameter. This material and water run through a sluice where gold is saved and are then deposited in the stacker buckets. With such a device under ordinal conditions a troughed belt stacker could not be used, as it could not handle the water. Any device that would remove water and deposit pebbles on the belt without too many complications would allow the use of the belt stacker. (See PI. XXXV, A, p. 184.) It would not be expedient to use a double or single lift dredge where ground is deep. To effect disposition of tailings while operating the double and single lift dredges it is necessary to keep the pond nearly full and to use very long digging ladders

U. S. Geological Survey

Bulletin No. 263 Pl. Xxxiv

A. Uncompleted Belt Stacker, Oroville, Cal.

B Troughed Belt Stacker, Oroville. Cal.

1'Ukin<;ton.

Dredging.

Stackers and tail sluices are of greater length than formerly. In early installations, without a single exception, stackers and tail sluices were too short, and difficulties due to improper disposition of tailings were of constant occurrence. Considerable areas of rich dredging ground, particularly when deep, have not been thoroughly worked, and much virgin ground has been covered by tailings to such a degree as to make it unworkable. The short stacker does not allow the coarse tailings to be discharged at a sufficient distance from the stern and at the proper height. There is consequently lack of room for fine tail-

Top of tailings

A Surface of ground

Fig. 35.— Tailings well stacked.

ings. In consequence the sand pump was brought into use, and the fines were discharged in such a way that much adjacent ground was covered by them. Valuable dredging ground, even now, is beingwasted in this way, as also by faulty manipulation of the dredge. The tailings have not been stacked with enough care to keep them well away from the sides of the cut when there is virgin ground on one or both sides.

Fig. 35 shows the cross section of tailings so piled as to waste no ground. It is assumed that the side slope of the cut is 45°, but this is

Top of tailings

Surface of ground]

Fig. 36.— Tailings poorly stacked.

the case only when ground is very free. "B" in the sketch is the boundary of the cut on bed rock. "A" is the boundary of slope to 45°. F G is equal to 2 F H. Tailings, as a general rule, should be so stacked that the distance from the tailings to the side of the cut at the surface of the water is about twice as great as the depth to which the dredge is digging.

A cross section showing the result of stacking tailings badly is indicated in fig. 36. This cut has been filled with tailings to point A', the boundary of the cut at the surface. In excavating the cut, of

184 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

which A', L, K, J is a part of cross section, it would not be possible to dredge beyond the point L in the direction of IV without having" to dig tailings in section IV, A', M, N. If the material in the triangular section is assumed to be loose and to stand at an angle of 45°, angle A', L, IV, the undredged ground in section PV, L, A' would be lost.

At first the relative merits in the use of a pivotal spud or a headline were considered almost wholly from the standpoint of actual excavation, and the difficulties of disposing of the tailings did not receive nearly the attention their importance demanded. In the opinion of the writer the pivotal spud should be used only by dredges of the double and single lift type whose sluices are sustained by auxiliary scows. Several dredges of these types in Montana, having broken a number of pivotal spuds while dredging a tenacious material, have substituted a system of rope anchorages which does not recommend itself to the writer, as it appears better to make use of stronger spuds. The rigging consists of four wire ropes leading- from a high frame at the stern to anchors ashore. The pivotal spud appears to be more effective in holding- the dredge wjien excavating- indurated material and prevents its surging and ramming the bank. Attempt has been made to prevent this movement in headline dredges by placing the buckets closer together and thus bringing about greater continuity of contact between the buckets and the dredging surface. This, however, has not been entirely successful. It is possible that the introduction of a number of rollers on the lower side of the bucket ladder and behind the lower tumbler would result in holding several buckets firmly against the material being excavated and prevent surging, as it is probable that this movement, in digging hard material, is caused by the alternate taking hold and letting go of the buckets, as only one bucket at a time is held firmly by the lower tumbler. The buckets behind the lower tumbler dig by their weight only, Avhich is insufficient to force them into hard material. The use of some such device as above suggested, if successful, would probably make it possible for a headline dredge to excavate indurated material with the very important advantages of mobility and the better distribution of tailings.

The use of lower tumblers of more numerous faces causes more buckets to dig at a time and results in less surging. It is possible that the use of a round tumbler of large diameter might entirely eliminate the surging, for there would then be no raising and lowering of the buckets as there is during the revolution of the tumbler of few faces.

The use of the pivotal spud introduces a number of problems in the disposition of tailings. The spud should be so located as to make the radius of the arc described by the buckets in digging as long as possible, thus permitting the excavation of a wide cut — an obvious advantage. This demands the placing of the spud at or near the stern. The

U. S. Geological Survey

Bulletin No. 263 Pl. Xxxv

A. Practice In Pond Dredging, Oroville, Cal.

B. Pilot House, Upper Deck, Starboard Side.

Purington".

Dredging.

older boats were provided with short stackers and tail sluices, which resulted in the narrow distribution of all the tailings, but more particularly the lines. Under these conditions the stern of the dredge was frequently aground, unless kept clear by the use of a sand pump. This difficulty has been remedied to a certain degree by the lengthening of stackers and tail sluices, but will always be much more serious for the pivotal-spud dredge than for the headline dredge. The headline dredge can use the maximum amount of tailing area. For example, in unusual cases, as in dredging a pay streak of defined boundaries, tailings can be deposited on barren ground outside of the cut. To accomplish the same result with a pivotal-spud dredge numerous changes of position would have to be made, an expedient likely to result in much loss of time and some loss of ground because of the difficulty of relocating the pivotal points. The wasting of unworked ground bj7 the faulty discharge of tailings is well illustrated by fig. 37. In this the distance from the pivotal point to the lower end of bucket ladder excavating at the maximum depth, called the digging length, is 90 feet. Here P x and P y represent the distances from the pivotal point to the point of discharge of the stacking ladder and are called "tailing lengths." Here the discharge is at points marked z and z' ', which are, respectively, only 18 feet and 5 feet from boundaries of cut, whereas they should be not less than 40 feet awa}, if the dredge be digging in ground 20 feet deep. It also shows that in some methods of manipulation too long a stacker is detrimental. This illustration is taken from two dredges now in operation.

In tig. 38 a method in general use is shown to prevent the covering

with tailings of unexcavated material adjacent to cut, To bring this

about it is necessary to move the dredge from P to P' as often as the

distances from C and C to x, while moving ahead in excavating arc

A, B, C, and in the advancing of tailings in arc x, y, z, become so short

as to make it difficult, as approaches P, and x approaches F, to

move to and dig in the other half of the cut. The changing of the

! dredge from one half to the other half of the cut is generally made

every few days and consumes considerable time. There is, moreover,

Spud digging with tailings piled too near unworked ground.

Gravel And Placer Mining In Alaska.

[bull. 263.

the constant danger of the dredge not being located with the pivotal point in the right place and thus, when changing from one half cut to the other, there is a consequent loss of ground. In this figure it is assumed that the dredge is digging %) feet below the surface of a pond on a bank 30 feet deep.

In fig. 39 the result of keeping the lines of advance of the pivotal points too close together is shown. The dumping of tailings at x' and x would result in grounding the dredge. In this case the distances from z and z' to sides of cut are unnecessarily great. It is evident that if the lines of advance of the pivotal points are kept too far apart ground adjacent to the cut will be wasted. In general, it may be said that where the material to be dredged is free, the headline method is

Fig. 38. — Correct spud digging from two pivotal spuds.

superior, and also, if by the introduction of some device, surging can be prevented, the headline method would be superior in dredging indurated material, for there the problem of the disposition of the tailings is much simpler. This permits of the use of shorter stacker and tail sluices and, therefore, smaller hulls and lighter construction.

There is a marked tendency now toward stronger hull construction, and longitudinal bulkheads or fore and aft keelsons are often introduced. Traverse water-tight bulkheads at the bows would be advantageous in dredges working in torrential rivers where there is danger of collision with floating trees; or, in rivers like those in Alaska, where ice may be encountered.

In some instances machinery too heavy for the size of the hull has been installed, and, as a result, there has been a lack of stability of the

Purington.]

dredge, with consequent disturbance of the grades of the gold-saving devices. Hulls are now generally made with overhanging houses, which give more deck room and permit of the location on board of a small though very convenient shop. The crowning of decks has resulted in cleaner and drier dredges.

Stronger gauntrees have been introduced in the late installations. The bow gauntree, at first considered merely as a support for the outboard end of the digging ladder, is made much heavier, as it is now designed also to tie together the bow pontoons.

The main gauntree, on which are sustained the upper tumbler and its driving gear and the inboard end of the digging ladder, is made much stronger than formerly, particularly when the upper tumbler has a gear drive and a good alignment becomes therefore essential. In

Fig. 39.— Sketch showing danger of grounding boat in tailings when pivotal points are too close

together.

dredges recently constructed the main gauntree has been made the vertical post in longitudinal and transverse trusses which tend to prevent the distortion of the hull, due to the great weights of the digging and tailing machinery, which are sustained respectively at extreme bow and extreme stern. Stern gauntrees have not been much modi tied, but have been strengthened and made somewhat higher, so as to sustain longer stackers.

The introduction of some form of derrick or crane, at the bow, to move stumps and other obstructions and to hoist machinery, is now common. The use of traveling cranes over driving and other machinery is not so general as it should be, for such devices save time and labor when, as is frequently the case, renewals or repairs are necessary. The machinery is now generally housed.

188 GKAVEL AND PLACER MINING IN ALASKA. [bull. 263.

The location of operating- levers, controllers, and switches is still a mooted question. Some operators prefer them on the lower deck close to the driving machinery; others in the pilot house, which is located near the forward end of the upper deck. In some installations they are placed in a pilot house just aft of the upper tumbler. With the first arrangement the winch man is among the driving machinery and can watch it, but unless he leaves his station he sees little of anything else and gets a poor view of the whole length of buckets. With the second arrangement the winch man can see the buckets better, all bowlines, but little else. With the third arrangement the winch man sees the buckets, the lines at bow and stern, the hopper, the screen, and enough of the gold-saving apparatus to know whether the riffles are clear, and with the aid of mirrors can also see the stacker and tail sluices. The objection to this arrangement and, in a measure, also to the second is that the winch man is isolated and therefore inaccessible (see PI. XXXV, B, p. 184). The type of dredge and height of upper tumbler should determine the position of the operating levers, controllers, and the switches, but in general it would appear that the advantage would lie with a location behind the upper tumbler.

Loss of time has always been a serious factor in the use of gold dredges. The first installed in the United States operated less than 50 per cent of the time. This was due to several causes, but principally to the time consumed in making repairs and renewals and the difficulties brought about by the faulty arrangements for disposition of tailings. Minor causes, such as lack of cranes and derricks, can be overlooked, being unimportant by comparison. The writer, however, has seen the removal of troublesome stumps consume hours when, almost without exaggeration, it may be said that minutes should have sufficed for this purpose. It is noteworthy that many operations are hampered by lack of a sufficient number of lights for doing night work on or near the dredges.

All dredges should be equipped with devices for hoisting and moving the driving, screening, and pumping machinery, but these are now often lacking. The belting, both for stacking and driving, has caused much loss of time — a result due both to the poor quality of belts and to the attempt to make belts do work for which were not intended. Friction clutches, hoppers, and screens of bad design and inaccessibility of parts of equipment have also brought about a serious loss of time. This is specially true of renewals of such pans as baffle plates of hoppers and perforated sheets of screens.

Cleaning up also consumes much time, and any arrangement that will permit continuous running during clean-ups of riffles charged with quicksilver will be of great value. Of late some managers have employed rather large crews to minimize lost time, though many dredges are still operated with but two men per shift.

Purington.] DREDGING. 189

The now general use of variable-speed motors on electric dredges has had good results. Constant-speed motors on headline dredges working in indurated material had brought the headline method of dredging into bad favor, whereas variable-speed motors permit a chain speed suitable for indurated material, with less surging and breakages. Under these conditions about the same amount of material is excavated, as a slow chain speed with low theoretical capacity has often in tenacious gravel a greater actual capacity than a high chain speed with high theoretical capacit}. This is due to the incomplete tilling of the buckets when running at too great a-chain speed.

In Alaska, where much frozen ground is encountered, the conditions are not favorable for the successful operation of gold dredges, especially as the long winter reduces the number of working days to about one hundred and thirty a year. Nearly all the deposits of auriferous alluvions are frozen, though some areas, notably in the beds of rivers, are unfrozen. Such unfrozen zones are easily dredged and large volumes can be cheaply handled. The depths to bed rock are moderate, but the bed rock is generally unfavorable for easy excavation, and the ground is characterized by a great concentration of values near and in it. Lateral concentration also is great and the pay streaks are often narrow. High costs of installation and operation are other drawbacks in regions far from the coast, to which freight charges are high. Considerable areas of so-called i4 worked out" ground in this northern field, particularly in the Klondike district of the Yukon Territory, would furnish excellent dredging ground if the material were not frozen. Steam thawing now costs about 40 cents a cubic yard, but a cheaper method of thawing would make much ground available for highly profitable dredging. It is probable that if wide cuts were made the banks might thaw as rapidly under exposure to the sun as they could be removed by the dredge. Another factor which may be of importance is that ground which has once been worked does not freeze to any great depth. It is evident that the chief problem of gold dredging in this northern province is in the thawing of the material, for many of the other conditions are favorable for profit - able exploitation by this means.

Had gold dredges been used in tne North when the first mining was done on the richer creeks much more gold would have been recovered and the cost would have been less, for the earlier methods were exceed ingly wasteful and costly. The overburden of muck could have been easily sluiced off and the thawing of the underlying gravels would have been easy when aided by exposure to sun and air.

In this northern region, because of the small vertical section and absence of much line sand in the gravels, dredges with short digging ladders and stackers can be used. This equipment demands only small, light hulls and machinery. Large volumes of thawed materi-.il can be

190 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

handled, but screening devices for saving coarse gold are essential. Bucket rather than belt stackers are preferable, for ice on the faces of the driving pulleys would cause slipping. The climatic conditions demand that the dredges should be completely housed, and that those driven by electricity should be equipped with electric heaters to supply hot water to the gold-saving appliances and thus permit continuing operations after cold weather has put a stop to hydraulicking and open-cut mining.

Open connected buckets will do better work in the heavy bed rock usually encountered in Alaska, and teeth on bucket lips will probably be effective. The use of several powerful digging teeth in the bucket chain, instead -of toothed buckets, to excavate heavy bed rock, was suggested by a manager of wide experience, and has worked well in several instances. A larger factor of safety should be allowed in designing dredging machinery intended for Alaska, and strenuous efforts made to minimize lost time in every feature of the construction, so that full advantage may be taken of the short available season.

Sluices And Gold-Saving Appliances, Excluding Hydraulic Operations.

Creek miners in the Klondike and Alaska placer fields have met, with extraordinary vigor and a considerable amount of success, the peculiarly difficult conditions attendant on mining operations in the Northwest. Inventive genius has been called largely into pla}r, since, except in parts of Seward Peninsula, tdraulic mining in working the creek deposits is not practiced. It is evident, however, to one who visits the Klondike district, that the methods there in vogue for working the rich creek deposits have been developed with special attention to the economical mining and conveying of the material to the sluice, while the washing of the gravel in the sluice is not, as a rule, conducted with a view to the saving of the greatest economic amount of the gold. Whereas in the hydraulic-sluicing methods the benefit of long experience has resulted in generally commendable practice, the smaller hand and mechanical creek operations frequently exhibit gross carelessness in the matter of gold-saving appliances.

The method of shoveling by- hand into a string of sluice boxes is naturally the one first tried by the miner in a remote district, working in shallow ground, after he has passed the panning and rocking stage. In these operations the cost, even under present northern conditions, varies from $1.25 to $2.50 per cubic yard (averaging $1.63), the capacity per man per shift averaging 5i cubic }ards. The most primitive appliances are the most economical. From three to six boxes, 12 or 14 inches in width by 12 inches deep by 12 feet long, on a grade of 6 or 7 inches to the box length, fitted with 6-foot 3-inch pole riffles made of saplings, form the customary rig in the interior where timber

purington.] SLUICES AND GOLD-SAVING APPLIANCES. 1H

is at hand. From 30 to 60 miner's inches" of water are used. Opera tions of this kind, where from three to twenty men shoved in, are to be found on all the gold-hearing- creeks exploited in Alaska, though in the Klondike they have been largely supplemented by methods employing less hand labor. As none but rich gravel can be so worked, exigency permits a loss of fine gold. It is rare that placer miners will admit that they are losing gold, but it is safe to estimate that in the interior, where two to five boxes are in use for saving, and where drop-oil's are not used, or are only such as are caused by the telescope connection of the boxes, from 10 to 20 per cent of the gold lifted into the boxes is allowed to return to the creek bed.

It would seem that heavy losses must occur in connection with the sluicing of the winter dumps taken out in drifting operations. The strings of sluice boxes are erected at as small an elevation as possible, in order that the greater proportion of the material will not have to be rehandled when the spring sluicing is done. PI. XXXVI, A, shows one method of dumping, in the winter, over previously erected sluices. Boards are laid over the sluices, and when sluicing is resumed the water is turned through the sluice, and, beginning at the lower end, the boards are successively removed. As much of the gravel as possible is caved in, sometimes with the assistance of a nozzle, and the remainder is shoveled, Avheeled to, and dumped into the sluice. Small bunkers or hoppers are sometimes built over the sluices, but no hoppers of large capacity, like those in use in Plumas County, Cal., were seen in the north. On Anvil Creek, in Seward Peninsula, a large winter dump was handled in this way, with the exception that those portions which could not be caved to the sluice were conveyed to it and dumped in by means of horse scrapers. Though loss of gold may be permissible in primitive operations of small capacity, it should become proportionally less when larger mechanical installations are made and the capacity of the plant is increased.

One of the early difficulties which the miner in the interior encountered was the presence of sticky clay and mud in the rich pay dirt. The difficulty was partly overcome by the introduction of the mud box, or puddling box, which was set in the middle or at the upper end of the string. Into this the men shoveled, or a bucket or car dumped. PI. XXXVII, A (p. 194), shows the form of the mud box used in the Klondike, and fig. 40 shows its position in the line of boxes. Its grade is generally made steeper than that of the rest of the string; 12 inches is common. The services of an extra man as stirrer, who also forks out the large stones, are required.

Where men shovel into boxes the mud box is used merely as a wide part of the sluice. In larger plants, where buckets, cars, or

a The term miner's inch used in this paper signifies an amount of water equivalent 1J cubic feet per minute.

Gravel And Placer Mining In Alaska.

[bull. 263.

derrick skips dump into the mud box, a platform, inclined at an angle of about 50°, 9 feet square, and built up of timber floored with rough scantling, is erected on the side of the box for the gravel to fall on.

The capacity of the sluice is cut down rather than increased by the use of the mud box, and the expense is increased by the cost of the man. A greater saving of gold is made, but at best the operation is expensive and of small and variable efficiency. In some shoveling-in operations the use of the mud box is advisable, but where mechanical self -dumping buckets are used, it is possible that some other form of agitator might be advantageously employed.

The developments of the open-cut and drifting methods of gravel mining have necessitated an enlarging of the sluicing capacity. With

Plan

Lmj

uu

w

A

Grade ,6 to 12" in 12' Side elevation

Front elevation

Rear elevation

Scale

O 1

i feet 1

Flume intake

i i i i

G. 40. — Mud box.

the enlarging of the capacity, however, there has not been a proportionate improvement in the construction of the gold-saving appliances. In other words, instead of drawing on the experience of the hydraulic miner and the dredge miner for the adoption of gold-saving methods, the creek miners of the Klondike have continued the method of the long, narrow sluice used for shoveling-in operations, amplifying its error and suffering the inevitable losses of fine gold which its use entails.

The average capacity of a small placer operation where hand labor is employed is 40 cubic yards a day of ten hours. Grant that the narrow sluice of 36 feet in length with pole riffles is most economical for the needs of such a mine. Now take an average summer drifting

U. S. Geological Survey

Bulletin No. 263 Pl. Xxxvi

A- Winter Dumps, Showing Previously Erected Sluice Boxes, Klondike.

B. Mud Box, Used In String Of Boxes.

purington] SLUICES AND GOLD-SAVING APPLIANCES. 193

plant, where the gravel is dumped into the mud box by means of the cable tram and self-dumping- carrier, like that illustrated in PI. XXXVII, A. The capacity is 175 cubic yards in twenty-four hours, and the cost is approximately $1.50 per yard. After it is hoisted from the shaft the material is elevated to a height of 25 feet above the surface of the ground. Water is pumped to this height for sluicing. The sluice consists of a mud box 16 feet long and 30 inches wide, on a 12-inch grade, tapering to the 14-inch sluice boxes which follow. There are eight of these, set on grade of 10 inches to 12 feet, furnished with pole riffles, which last three weeks only and cost $3 per box length to renew. The man forking in the mud box costs $6.50 a day of ten hours. At this plant the gold is in part very finely divided, and it is impossible to believe that the sluice in use is operating with economy.

Proof of the losses now going on in the Klondike was seen on a neighboring creek. At a plant somewhat larger than the one above described, where 240 cubic yards a day were handled at a cost of $1 a cubic yard, a small undercurrent had been installed, at the end of ten 16-inch boxes, 12-inch grade, pole riffles. The undercurrent was fed through a small iron grizzly, and consisted merely of one 16-inch sluice box, 12 feet in length, with a riffle of cocoa matting and expanded metal. It cost $20 to construct this device, which was saving an average of 5 per cent of the product each day. A sample of the gold was taken, and although some of it is too fine for handling, such particles as could be weighed and counted gave a result of 280 colors to the cent, the gold being worth $15.60 per ounce. Gold of finely divided but never flaky character was seen in all the large producing creeks of the Klondike, and at the new Fairbanks district of Alaska.

The plants above referred to represent the average capacity of the creek mines of the interior of Alaska, where the hoisting of material, and frequently the pumping of sluice water are necessary. It costs from $3,000 to $5,000 to rig up such plants, which are used for three seasons or longer. To install a washing plant in such a case as the above would add little to the first cost, and the additional expense would probably be justified by the results.

Before entering on suggestions as to the use of washing plants, I wish to emphasize the fact that the methods of sluicing in use in Alaska, especially in the Birch Creek, Fortymile, and Fairbanks districts, and to a certain extent in Seward Peninsula, have been, and will continue to be, influenced by the Klondike developments. Though many of the methods developed in the Klondike are excellent and are worthy of imitation in any country where conditions are similar, at the same time the Alaskan miners should note the wrong principle of the primitive sluice box which has been continued there. The entire Bull, 263—05 13

Gkavel And Placer Mining In Alaska.

absence of screening or use of grizzlies, other than the rough, expensive hand method employed, renders valueless much ground which could be worked. A plant costing $5,000, designed to thaw, excavate, hoist, convey, and wash 150 cubic yards a day at a cost of $1 a yard, could, by an addition of from $500 to $2,000 to the first cost of the plant and an addition of 10 cents per yard to the cost of washing, recover at least 10 per cent more value in gold from a cubic yard of material.

It may be said that the fine gold found in the Klondike does not occur in the Alaska creeks. This is disproved by experiments made on small parcels taken from pannings on the various creeks. Fine gold from Fairbanks Creek, in the Tanana district, runs 500 colors to the cent, the gold being worth $17.70 per ounce. A small proportion of gold from Ophir Creek, in Seward Peninsula, was found to run

O 0

Oop

Punched holes 3/a"

Punched holes 3/e' Alo.9 Iron or steel

Cross section of a hole h plate

ifeet

Fig. 41.— Modified Caribou undercurrent.

170 colors to the cent, the gold being worth $18.50 per ounce. No means of knowing the proportionate amount of this gold is possible, as with the methods at present employed very little of it is recovered. Five per cent is considered a fair average of the total gold represented by the above fineness of division. This gold, which is not flaky in spite of its tine character, could easily be saved with the proper appliances, and there is no doubt that much coarser gold is lost.

The question will be asked, Can a cheap and efficient washing plant be installed, where gravel must be elevated by power, which will not add greatly to the cost, and the parts of which can be easily and quickly made with the materials at hand?

On the principle that gold is best saved in the thinnest sheet of water which will carry the tailings away, it is evident that for fine gravel a wider sluice is better than a narrow one. In narrow sluice boxes,

U. S. Geological Survey

Bulletin No. 263 Pl. Xxxvii

A. Mud Box On Gold Run, Klondike.

B. Oroville Riffles Used At Atlin, British Columbia.

Purington.

Sluices And Gold-Saving Appliances.

full or nearly full of water running with great velocity, fine gold will be carried along. Lengthening the sluice will not help matters. In fact, a short sluice with drops or undercurrent attachment is frequently more effective than a long sluice without it.

In a given case assume that the ordinary 14-incn boxes are widened to 24 inches, and that 5 boxes, with a grade of 9 inches to the box, fitted with the ordinary sapling-pole riffles, as at present, are succeeded by 3 boxes with the form of screen represented in fig. 41, the grade being made adjustable by means of blocking. An addition of 19 inches to each of the 3 boxes would compensate for the loss of grade consequent on the uptilting of the screens. The whole drop in the string of boxes would be 103. 5 inches as against 108 inches were 12 boxes used with 9-inch grade. Under the punched iron plates riffles of one or more kinds as described below, charged with quicksilver, should be used. The riffle shown in fig. 42 will be found satisfactory. Mats, plush, or blankets may under certain conditions be found more economical. A short transverse table following the last box, arranged under a grizzly from which the large material is discharged to the dump, will enable the operator to determine whether losses are occurring in the main sluice and screening boxes.

The above installation is in principle a series of undercurrents combined in the main sluice. Its advantages of cheapness, adaptability to conditions, and simplicity recommend it. No extra power or water is required. On the other hand, the use of the mud box is not obviated. " Regarding the use of punched plates in working New Zealand gold-bearing marine deposits, Mr. H. W. Young" says:

LThe best size of perforation for hopper plates has been a matter for experiment by y self and others, variations from one-fourth inch to five-eighths inch having been put

Scale of feet

Fig. 42. — Improved Hungarian riffle used at Oroville.

a Report of New Zealand Minister of Mines, 1902, p. 21.

Gravel And Placer Mining In Alaska.

[Bull. 263.

to working tests. It is proved that holes of less than three-eighths inch diameter unduly limit the discharge through the plates, are liable to choke, and that there is no advantage whatever to be gained by their use. The discharge through sevensixteenths inch holes is sufficient in amount, and the fine shingle particles which pass through with the sands and seldom exceed one-fourth inch in diameter are not troublesome in their size and quantity. In fact, many consider that they are of benefit in keeping lively the sands on the tables. With holes exceeding sevensixteenths inch in diameter, the size and quantity of small shingle become excessive, and the water passes away so rapidly as to prevent material from being carried forward over the plates.

The above remarks are of somewhat general application for the use of punched iron screens in any form of undercurrent where it is assumed that a portion of the gold, including any nuggets which may occur,

Plan

Pole riffles

Punched

iron plate

%"h\o/es

Pole riffles

Punched iron plate 3/Q" holes

Hungarian riffles (see fig. 14)

Longitudinal section of both main sluice and undercurrent

Section on line A -B Fig. 43.— Kulibinka sluice and undercurrent used in Siberia.

has been previously saved. In northern deposits where dredges have been installed, as in the Klondike and on Stewart River, punched iron screens used in revolving trommels have large holes, up to 11 inches, even when a tailings stacker is used, while the average size in Oroville dredging practice is three-eighths inch.

A screen installed in one box of the main sluice of a plant on Ophir Creek, Seward Peninsula, consisted of a number of longitudinally disposed round iron rods, acting as a grizzly, fitted above the bottom of the box, the gold being saved on mats below. This box, which was placed at the end of a 120-foot sluice, was said to save much fine gold.

When it is desirable to introduce the principle of the undercurrent,

purington.] SLUICES AND GOLD-SAVING APPLIANCES. 197

separate from the main sluice, the following device, adapted from one used in Siberia, as described by Mr. E. D. Levat," may be adopted. Its capacity is given as 172 cubic yards per shift. The principle of the undercurrent is here introduced, but the discharge, of both coarse and line, is to the same heap. This contrivance uses no power, and the method of handling- accumulations of tailings will be more expensive than in plants already in use. Where the steam scraper is so generally employed, however, as in the Klondike for handling tailings, the innovation of the modified "kulibinka" here figured (fig. 43) would not add over $1,000 to the expense of installation, while the efficiency in saving the values would be greatly increased.

It has been shown that the Klondike sluice generally necessitates a man forking. The object of this forking is to take out the stones, from 6 to 18 inches in diameter, after their surface is washed. Mechanical devices for accomplishing this would be advantageous. Experience with gold dredges has proved that the revolving screen or trommel, inside of which play powerful jets of water, accomplishes this screening process most successfully. The trommel is, however, expensive, and its various parts and castings must be specially made at elaborately equipped works. Therefore it is worth while to consider whether simpler and cheaper devices will not accomplish nearly as good results for the Alaskan miner.

A plant to accomplish good washing results with sticky clay and gravel, and which can be built of materials at hand, is shown in fig. 11. This type of plant, founded on the idea of the Siberian pan, has a capacity of from 100 to 200 cubic yards in ten hours, and can be built in the winter months. Assuming that steam power is already at hand, it requires no outside material beyond the iron shoes and simple castings and the punched steel plate which forms the floor of the pan. Its operation will require 10 horsepower, and if the material is conveyed to it by the self -dumping carrier, the services of two men are sufficient to take care of the tailings. The machine will not only break up and thoroughly wash clayey gravel, but with properly arranged tables below will save the bulk of the fine gold which has been set free from its matrix. The cost of a pan of the dimensions here figured will not exceed $2,000, including the tables and sluices. The device for automatically clearing the bottom of the pan of large stones is not used in Siberia, where hand labor is cheap enough to dispense with it, the large stones being periodical removed b}T the lifting of gates in the periphery of the pan. The amount of water used in such a machine does not exceed ordinarily 125 miner's inches.

The drawing of this machine is made diagramatically, since the manner of its construction will depend on local conditions. A four-armed casting, keyed to the shaft and bolted to the horizontal timbers, is

aLevat, E. D., L'Or en Sib6rie orientale, Paris, 1897.

Gravel Ant) Placer Mining In Alaska.

[Bull. 263.

advisable. As used in remote districts in Siberia, the central shaft is frequently a wooden beam, and instead of the iron shoes, heavy stones dragged with chains, as in the arrastre, may supplant them.

The above suggestions are made with reference to working the rich gravels of the shallow northern placers. Gravel containing less than $2 to the cubic yard is rarely worked by the method of the cable and

Sections on line Y-Y

stee/ plate inclined toward shute with gradepf3"in 8'and [ punched with '/e"to l*'ho/es

Fig. 44.— Modified Siberian pan for handling clayey gravel.

traveling bucket. Lack of natural grade makes it necessary that the miner shall elevate his material, and the impossibility of getting water under head makes the use of steam power imperative. The point is that when such elevation is attained, it should be made available to thoroughly wash the gravel. At present this is not done. Perhaps the suggestions here offered may be of benefit to some operators.

tURiNGToN.] SLUICES AND GOLD-SAVING APPLIANCES. 199

In the construction of washing plants of a larger and more expensive kind, the operator has the benefit of the experience developed in gold dredging. This now rather important industry has brought into service devices for gold saving, in the use of which one of the main objects is to utilize to the best advantage all available vertical and areal space.

The employment of large mechanical excavators for placer mining has a held in the Northwest. Such operations necessitate one or more permanent washing plants to receive the gravel from each machine. It has been demonstrated that the dredge is the only form of excavator which can economically transport its sluices as it moves. Therefore a plant, situated as safely as possible with reference to danger from floods, and economically with reference to tramway, dump, and water supply, must.be constructed frequently at a considerable expense.

The shaking screen, although it has received a thorough trial on gold dredges, does not find as much favor as the trommel. It is not impossible that modifications of the principle of the shaking screen and of the shaking table may be developed which will act more efficiently in saving gold than the trommel. Mr. Felix Francois a has recently figured and described a " shaking sluice-box " system of gold saving, for installation either in stationary washing plants or in dredges. He claims a very high percentage of saving, and as additional advantages the elimination of the use of quicksilver and the employment of a small amount of water. He does not give the cost of the plant, however, nor any actual results of its operation in practice.

The use of the trommel in a stationary washing plant is illustrated in PI. XII, A (p. 80), a plant erected in the Klondike in connection with a steam shovel and incline operation. A short description of this plant is appended, but it should be understood that for the average miner the installation of such a plant is impracticable on account of first expense and the difficulty of getting the complicated machinery. The plant used 125 miner's inches of water, led by a ditch from Bear Creek; the capacity was said to be 500 cubic yards in ten hours. The material elevated to the platform at the upper end of the trommel was dumped into a hopper feeding the trommel. The water was led into the lower end of the trommel and fed through a perforated pipe. The largest holes in the revolving screen were 1 inch in diameter, and all oversizes passed through and into the hopper below the lower end, whence the tailings were hoisted in a self -dumping carrier, on a cable, for a horizontal distance of 200 feet and a vertical distance of 60 feet. The fines passed over 80 square feet of riffle tables, floored with expanded metal and cocoa matting, on a grade of 12 inches to 12 feet, followed by sluices with iron Hungarian riffles. PI. XII, i>, shows the

a Bull. Soc. de Industrie minerale, vol. 3, 1894, p. 785.

200 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

expanded-metal form of riffle table, which has given good satisfaction. The f-nes were, after passing out of the 96 feet of sluice boxes following the tables, elevated by a steam scraper to a pile 200 feet distant and 15 feet high. The expense of installation of such a plant will be not less than $5,000, and will more likely be $10,000 in any part of the interior of Alaska.

In arranging a number of gold-saving tables to receive the discharge from a screen, great care should be taken to distribute the material equally to these tables, so that the duty of each may be the same. This in the best Oroville practice is done by leading a small sluice trough from the main receiving sluice beneath the screen to each of the tables. In case of a second sizing, as in the Atlin dredge described below, the distribution is necessarily accomplished by a series of grizzlies in the main sluice. If small ducts or troughs are used, they should be provided with gates, the whole made of wood, like those used for distributing the pulp to the tables in concentrating mills. The attempt to distribute the fines directly from the trommel by means of iron gates is considered less satisfactory.

Riffles for the saving of fine gold in sluices are of many kinds and are of very ancient origin. Humboldt (Asie Centrale) refers to the

Scale of feet

Fig. 45.— Pole riffle fitted with knives for breaking clay.

method in use of working the placers of Colchis — that of employing wool in the sluices — as a possible explanation of the legend of the "Golden Fleece." It was in fact known that the kings of Imeret in the eighteenth century used wool for collecting gold in Tskinitskali and Abacha rivers in the Caucasus, while Turkish gypsies use goatskin for gold saving on Belichta River.

The pole riffle made of saplings, with or without strap iron nailed to the top, has long been in favor in small placer operations in the United States, and is to-day employed in the primitive shoveling-in operations throughout the northern territory. An improvement on this riffle, simply made, aiding in the disintegration of clay, was seen by Mr. Frank L. Hess in the Rampart district of Alaska, and a sketch furnished by him is shown in fig. 45. Small squares of sheet iron one-sixteenth inch by 2 by 2 inches are driven cornerwise into the poles.

A development from the wooden pole riffle is the iron or steel rail, laid longitudinally in the sluice box. One type of rail riffle used in Seward Peninsula is shown in fig. 32. It will be noted that the T lies with its horizontal extension uppermost, that the rails are joined

purington.] SLUICES AND GOLD-SAVING APPLIANCES. 201

in gangs of four, and that a locking device is employed to prevent the gangs from coming up. Rail riffles of this kind are primarily intended for hydraulic operations and give excellent satisfaction, but can be recommended for creek placers only where the capacity warrants expensive installation.

At the present day the saving of fine gold is receiving marked attention on gold dredges, as the product of these machines frequently consists largely of gold in an exceedingly fine state of division. Fig. 42 and PI. XXXVII, B, represent a sluice table now in use at Oroville, Cal. The grade of the table on the dredge at Atlin, British Columbia, is 12 per cent, corresponding nearly to 18 inches to 12 feet. These tables are set transversely beneath the main sluice, which is fed directly from the trommel, the main sluice having a grade of 12 inches to 12 feet. The quicksilver charge of the sluice and table is 200 pounds. The largest material passing over the sluice is 4 inches in diameter, while grizzlies do not permit over-J-inch sizes to go over the undercurrent tables. The total area of sluices and tables is from 600 to 1,000 square feet, from 500 to 700 miner's inches of water being used for an amount of material which will probably average 1,500 cubic yards per twenty-four hours.

The type of riffle here figured is used extensively at Oroville at present. It is stated by one of the operators who has experimented with the gold in that field, that from 15 to 20 per cent of the gold recovered with quicksilver, using this riffle, will pass 150-mesh sieve.

The expanded metal and cocoa matting riffle is also used with success at Oroville.

The Oroville gold contains a much larger proportion of fine colors than the northern fields. From the undercurrent sample of Klondike gold above described, assuming that this represents 5 per cent of the total recovery, screening tests appear to indicate that under 1 per cent of the Klondike gold, and under 2 per cent of the Fairbanks Creek gold, will pass 150 mesh.

The fineness of the gold on Sulphur Creek is shown by the tabic below :

Fineness of gold from Sulphur Creek. Mesh. Per eent.

Under 150 10

150-100 00

100-80 20

Moreover, the gold, whatever its fineness of division, is generally round and shot-like and not flaky. Under such conditions, in view of the Oroville experience, losses such as undoubtedly occur in the northern practice are inexcusable.

The riffle shown in fig. 46 is designed to hold a divided sheet of quicksilver. Another form is made by boring 1-inch augur holes to

Gravel And Placer Mining In Alaska.

[bull. 263,

the depth of one-half inch. Some operators claim that a recurring quick jar imparted to the fine gold tables by means of an eccentric or other device aids the saving of the gold. The efficiency of this principle is questionable.

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i i i i

l l l 1 i 1

i i i i

i i i i i i

i ill

I 1 1 l I i

h

— 2 feet

Fig. 46.— Riffle to hold divided sheet of quicksilver.

H

On the Snowfiake claim, a bench claim, worked by drifting, situated between Anvil and Dexter creeks, much of the gold sluiced from the winter dump was porous, occurring in lumps one thirty-second to onefourth inch in diameter, resembling dentist's gold. A peculiar riffle shown in fig. 47 was devised, consisting of sawn blocks nailed to riffle strips.

vn x

7 rv n r~7

Fig. 47.— Special block riffle for saving porous gold.

This riffle used in 14-inch boxes, on 8-inch grade, with 50 miner's inches of water, was said to be the only one of many tried which would catch this gold.

Puris'Otok.]

Sluices And Gold-Saving Appliances.

m

[

Fig. 48 shows an excellent iron riffle used in the smaller sluices of Seward Peninsula for saving gold of average fineness. The castings are light, can be easily handled, and can be set in the sluices so that the long dimension of the slots lies either transversely or longitudinally. The longitudinal arrangement has been found to be the better.

The use of quicksilvered copper plates is not likely to give increased saving in Alaska placer operations. Blankets, mats, or other fabrics are not generally used on account of their expense.

Mr. H. W. Young a has designed for the Waiwhero Sluicing Company, of New Zealand, a form of apparatus for the saving of fine gold which is used in New Zealand beach deposits where the gold is accompanied by an excessive amount of black sand. A few of Mr. Young's remarks are here quoted:

The modern fine gold washing plant, as used on the West Coast, consists of three main essential parts. The first is the hopper box with stone shoot, which receives the water and gravels from the tail race connecting with the sluicing face, and separates the stones and shingles from the water and sands. The second comprises the "sand box" or "boil box," with its discharge ducts and other accessories, intermediate between the hopper and the tables. The third comprises the washing tables and their accessories. The three essential parts deal with the stuff from the face, and reduce it to concentrated gold and heavy sand ready for amalgamation.

The introduction of a sand box or agitation box, in which the material is kept in agitation by being made to pass over and under a system of baffle boards before passing to the tables, as described by Mr. Young, is of obvious advantage in connection with the plant described. The principle will undoubtedly be of use in some of the washing plants of Alaska, as it provides a moderate stirring action without the use of mechanical power. The quantity of water economical for such a plant as the one described, with material screened to seven -sixteenths inch size on tables with a grade of 12 inches to 12 feet, is in the proportion of 40 miner's inches to each 10 feet of width of table. As at Oroville, the value of separate ducts from the feeding or sand box to each table has been proved.

The clearing of the gold from the accompanying minerals of high specific gravity is often difficult. In the creek workings on Bonanza

6 inches

Fig. 48.— Iron-grate riffle, Seward Peninsula.

i Report of the New Zealand Minister of Mines, 1902, p. 20.

204 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Creek, Klondike, for example, of the total weight of gravel handled, 1 per cent of black sand, mostly magnetite, is caught with the gold in the clean-up. In American Creek, Alaska, the clean-ups are impeded by the presence of large quantities of barite pebbles. In the Fairbanks district red garnets and rutile, in some cases in quantity up to one-third of 1 per cent of the total material washed, are caught with the gold. In the Birch Creek district there is enough rutile in the auriferous sand to cause trouble in the clean-up. In Seward Peninsula the magnetite is in comparatively small amount. Garnets occur in the creek diggings up to 5 pounds to the cubic yard of gravel. In the beach and so-called "tundra" gold sands of the coastal plain from 3 per cent up to as high as 61 per cent of garnets occur/7

The use of quicksilver in the northern operations of America is limited. Even allowing for the extra expense and time consumed in the use and recovery of quicksilver, it is surprising that this important agency for saving fine go\d is not more generally employed. It has been shown that the proportion of fine gold in the interior fields is large. The neglect to use quicksilver in attempting to save such gold can be considered only as a penny-wise-pound-foolish polkyy. It is needless to say that in all of the appliances above suggested for the saving of fine gold the use of quicksilver is imperative. Carelessness in the use of quicksilver, however, may result in increasing rather than diminishing the loss of fine gold. According to Bowie/' float quicksilver containing microscopic gold particles has been taken from the surface of the water 20 miles from the place where the amalgam entered the stream. A single flask of quicksilver is ample for the needs of the average creek operation of the Klondike or interior Alaska, and even with wasteful handling would last a season.

Whether quicksilver is used or not, it will be found advantageous to get the gold and amalgam as clean as possible on the floor of the sluices or tables before removing the valuable product. The comparatively small amount of heavy concentrates accompanying the creek gold of Seward Peninsula makes this possible in the frequent clean-ups of] the tailrace. Skillful manipulation will accomplish the same result in the interior except where excessive quantities of magnetite occur. In one case on Bonanza Creek, Klondike, the fine concentrates which could not be removed with the magnetite after drying were skillfully separated by dry-panning.

Black sand or other concentrates have occasionally been found rich enough to pay for sacking and shipping to smelters after cleaning. Exaggerated reports of high assays in gold obtained from black sand frequently find credence. Nevertheless, whenever this concentrate

a Brooks, A. H., Mendenhall, W. C, Collier, A. J., and Richardson, G. B., Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in l'JOO, I), g. ftepV. Survey, 1901, p. 87. b A Practical Treatise on Hydraulic Mining in California, 1885, p. '244.

purington.] CLEANING, RETORTING, AND MELTING. 205

accumulates in the sluices or tables in an}r considerable amount, it should be sampled and assayed to ascertain the amount of finely divided gold which still remains in it.

Cleaning, Retorting, And Melting.

If amalgam is to be treated, it should be well stirred, either in buckets or large porcelain mortars, and the base material — sand, scraps of iron, etc. — which comes to the surface should be skimmed off.

This residue (which holds considerable amalgam) is concentrated by washing in pans or rockers, and the concentrations ground in iron (or porcelain) mortars and treated with more quicksilver. Any base material which floats on the surface of the bath is melted by itself to a base bullion. The remainder is added to the fine amalgam. The amalgam is strained from the quicksilver through drilling, and the dry amalgam is retorted in iron retorts.

In cleaning the placer gold, when no quicksilver is used, a magnet inside a cotton sack passed through the dust will remove all the magnetite. Minerals of high specific gravity not attractable by the magnet are not easil}' removed by mechanical means. Rutile, garnets, and ilmenite are examples of these occurring in Alaska. In small operations the gold dust is roughly cleaned from these minerals by blowing and dry-panning. Where the amount of gold is considerable, a melting plant is advisable. In retorting amalgam, small hand retorts will in general be found adequate.

Before the amalgam is put in the retort the interior is coated with a thin wash of clay, which prevents the amalgam from adhering to the iron.

The amalgam should be carefully introduced and evenly spread. The iron pipe which connects the back end of the retort with the condenser must be clear of all obstructions, and under no circumstances should the amalgam be spread so that the pipe can possibly become choked, as in that case an explosion would probably ensue.

To avoid any danger arising from this source after the cover has been put on, lined with either clay or a mixture of clay and wood ashes, and securely clamped, the fire is lighted and the heat gradually raised, a dark-red heat being all that is necessary to thoroughly volatilize the quicksilver. Toward the end of the operation the heat is raised to a cherry-red color, at which it is kept until distillation ceases. The retort is allowed gradually to cool, and when cold is opened.''

A stream of cold water should be always flowing through the jacket which incloses the condensing pipe, so that by no possibility can mercurial vapor pass into the receiving vessel in which the lower end of the pipe terminates. The discharge end of the pipe should be kept under water during the retorting operation.

When gold accumulates in sufficient quantities to make the shipment of the dust inconvenient, the metal may be melted on the ground and molded into bricks. Both for convenience of shipment and facility in guarding against losses, this practice is to be recommended. A brief description of the essential features of this work follows.

a Bowie, op. cit., p. 249. & Bowie, op. cit.

206 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

In melting, a gasoline 2-jet furnace may be used. Gasoline under a pressure of 30 pounds enters a heating coil attached to the burner. The heating coil is so arranged and fed that liquid gasoline burning on the outside of the main feed vaporizes the gasoline which is used within the furnace. With the 30 pounds pressure used a very hot flame is the result. The gasoline supply should be stored without the building and brought in through pipes, so as to reduce the danger of explosion. An air barrel connected with the supply line and supplied Avith a small hand pump serves to keep the gasoline pressure as high as may be necessary. The furnace is made of sheet iron and lined with fire brick. A cover of asbestos and iron serves to retain heat. This should be so constructed as to allow the bolting on of new iron plates, as they burn off with the great heat generated. The operator should be supplied with asbestos gloves.

Crucibles are of various sizes. A No. 30 crucible, costing between $2 and $2.50, will hold from 900 to 1,000 ounces of impure gold or bullion with the necessary fluxing charge. They are composed of a mixture of line clay and graphite, and to prevent breaking certain precautions should be observed. A new crucible should stand near the furnace, at least during two melts, and when first used should be heated gently. This precaution is not necessary when a crucible has once been used. After a crucible has been used five or six times it can not be depended on and it would be economy to discard it, as breaking during a melt is a source of great inconvenience and loss of time.

It is necessary to have an iron table near the furnace, upon which can be placed gold pans, shovels, tongs, etc.

Before the gold is placed in the crucible it should be accurately weighed and cleaned with a magnet, as above described.

In melting 900 to 1,000 ounces, three-fourths of a pound of borax should first be melted in the crucible as a flux. After the dust is : poured in, one-fourth pound of soda with one-half pound of borax should be placed on top. The soda unites with the silica of the sand, but in perfectly clean gold is not needed. The borax unites with the iron occurring with the gold. When the dust is mixed with considerable iron pyrite it is well to add a small quantit} of scrap iron. This, in uniting with the sulphur, forms iron sulphide, which comes off in the slag. If this precaution be not taken a hard matte, very difficult to remove, forms upon the brick.

During the melt it is necessary several times to skim the slag from the gold. A special instrument is used for this purpose, essentially a long rod bearing at its lower end an enlargement to which the slag will stick. After gathering a small quantity upon the skimmer it is brought out, and by rolling on the iron table is made into a smooth, diskshaped mass upon the end of the rod. This operation is continued until the slag collected upon the skimmer becomes unwieldy, when it is cooled by plunging it in water and broken off. When the gold is

Pl'RINGTON.]

Fineness Of Alaskan Gold.

reached it may he readily detected by its greater weight. A second flux of borax alone is then added, and when this has melted the product is ready for pouring.

A small crane to lift the crucible from the furnace and to pour the gold into the mold should be rigged overhead. Special tongs for lifting the crucible are made.

Though the mold should not be heated too much, it should always be raised to such a temperature that oil will burn on contact with it.

On removing the bullion brick from the mold it is placed in a pickle of three to four parts of water to one of nitric acid, which serves to clean the gold of surlicial deposit. By using a hammer and a steel slag brush the brick is made ready for shipment.

Fineness Of Gold.

The following table shows the fineness of Alaskan gold: Table 13. — Fineness of gold by districts and. creeks.

District.

Fineness.

Authority.

Juneau :

Per ounce.

Gold Creek

$17.50

Operator. Do.

Windfall Creek

Lemon Creek

Do.

Porcupine:

McKinlev Creek . .

Members U. S. Geological Survey. Do.

Porcupine Creek

Nizina:

Chittitu Creek

Operator.

Dan Creek

Do.

Chisna:

Miller Gulch

Do.

Slate Creek

Do.

Headwaters of Copper River

Do.

Sunrise:

Sixmile Creek

Members U. S. Geological Survey. Do.

Crow Creek

Atlin:

Pine Creek

Operator. Do.

Willow Creek

Spruce Creek

Do.

McKee Creek

Do.

Birch Creek

Do.

Gold Run

Do.

Klondike:

Bonanza Creek:

(a ) High bench

Bank British North America.

( b ) Creek

Do.

208 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Table 13. — Fineness of gold by districts and, creeks — Continued.

District.

Fineness.

Authority.

K londike — Continued.

Hunker Creek:

Per ounce.

(a) Bench

$17. 75

Bank British North America.

(6) Creek

Do.

Dominion Creek

Do.

Gold Run

Do.

Sulphur Creek

Do.

Bear Creek

Do.

Last Chance Creek:

(a) Bench

Do.

(6) Creek

Do.

Forty mile:

Wade Creek

Do.

Walker Fork

Operator. Do.

Chicken Creek

Stone House Fork

Do.

Irene Gulch

Do.

Eagle :

American Creek

Bank British North America.

Mission Creek

Do.

Circle district:

Dead wood Creek

Do.

Mastodon Creek

Operator. Do.

Mammoth Creek

Miller Creek

Do.

Eagle Creek

Bank British North America.

Mastodon Fork

Operator. Do.

Woodchopper Creek

Fairbanks:

Fairbanks Creek

Bank British North America.

Cleary Creek

Do.

Pedro Creek

Operator.

Bank British North America.

Chatham Creek

Twin Creek

Operator.

Rampart:

Little Minook Creek

Bank British North America.

Little Minook, jr., Creek ..

Members U. S. Geological Survey.

Hunter Creek

Do.

Baker Creek

(a) Bench

Do.

Thanksgiving Creek

Do.

Glen Gulch

Operator. Do.

Gold Run

purington.] FINENESS OF ALASKAN GOLD. 209

Table 13. — Fineness of gold by districts and creeks — Continued.

District.

Nome:

Anvil Creek

(a) Bench

(6) Creek

Glacier Creek

Dexter Creek

Dry Creek

(a) Creek

(6) Bench ...

Beach diggings

High benches

Grass Gulch

Peluck Creek

Hastings Creek . . .

Basin Creek

Bonanza Gulch . . . Council:

Ophir Creek

Crooked Creek

Mystery Creek

Solomon:

Solomon River

Big Hurrah Creek Port Clarence:

Gold Run Creek .

(a) Bench

{b) Creek

Anikovik River.

Sunset Creek

Fairhaven:

Bear Creek

Hannum Creek . . .

Inmachuk River . .

Candle Creek

Kougarok:

Gold Run

Alder Creek

Kougarok River. . .

Homestake Creek .

Fineness.

Per ounce.

$18. 60

Authority.

Bank of Cape Nome. Do. Do. Do.

Operator.

Do. Bank of Cape Nome.

Do.

Do. Operator.

Do.

Bank of Cape Nome. Do. Do.

Do. Do.

Operator. Do. Do. Do.

Members U. S. Geological Survey.

Do. Bank of Cape Nome.

Do.

Do. Do. Do. Operator.

Bull. 263—05 14

210 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Labor.

The following table (14) shows the average wages paid for labor in the mining districts of Alaska and adjacent Canadian territory during the summer of 1904. When the prices for winter work were available such have been added. The prevailing wages have been placed under the names of the districts as these are generally known, it being understood that the name of the nearest town, as, for example, Nome, stands for the creeks in the vicinity. Timbermen, carpenters, blacksmiths, and others whose pay is generally higher than that of ordinary laborers in the United States, are rarely paid more in Alaska. In districts where steam-thawing methods are employed engineers include pointmen. Hoistmen are not classed as skilled laborers, and where special prices for engineers obtain the men are usually in charge of large engines or pumps.

Two shifts are worked on most of the mines, especially in the summer. In hydraulic operations at night only one-third or one-fourth as many men are employed as on the day shift. In steam -thawing operations, where thawing is done at night, one or two pointmen and a fireman on the night shift generally take care of all the thawing, which will employ from 10 to 20 men in excavating, tramming, hoisting, and washing during the following day shift.

Ten-hour shifts are the rule throughout the northern placer fields. In large hydraulic operations the pipemen, as in other regions, generally work twelve hours. At only a few places were men seen working an eight-hour shift. At one of these, where men were shoveling into sluice boxes, it was proved by actual measurement of the ground that the number of yards shoveled per shift per man was greater than on adjacent claims where ten -hour shifts were in practice. In one instance on Ophir Creek, in Seward Peninsula, two elevenhour shifts were worked, the men being paid 50 cents an hour and board. Experience has proved that the eight-hour shift for hard plvysical work is most economical in the operations in Alaska, where a large number of men are employed in shoveling and where every moment of the short season is valuable, and it would seem that the division of labor into three shifts of eight hours cheapens rather than increases the cost of handling material.

In some of the camps of Seward Peninsula a hospital fee of $2 per man per month is charged. This gives the laborer the services of a competent physician in case of sickness. Alaska is a singularly healthy country at all times of the year, and, although detailed statistics are not available, the proportion of deaths and illness to the total population would seem to be remarkably small.

Furington.]

Labor.

Table 14. — Scale of wages in Alaskan camps, including Dawson, Yukon Territory, and

.I/Mi, British Columbia.

Laborers.

Foremen.

Engineers.

Juneau

$3.50 to $4, without board; pipemen, $5.

$5 to $10 a day; some $12.50; some $90 to $150 per month.

$100 a month and board. .

$5, without board.

$5 a day, without board.

Chisna

Nizina:

Copper Creek . . . Dan Creek

$7.50 a day

Sunrise

$4 a day, no board

Porcupine

$3 and board

$4 and board...

Atlin

$3.50 to $4.50 and board; $5 to $6.50, (pipemen), without board.

$3.50 to $5 and board; winter, $3 and board.

$5 and board ; $8, no board .

$4 and board.

Dawson

$10 a day, no board.

$4 to $6 and

Fortymile

Eagle

board.

$5 and board

Rampart

$5 a day and board

Birch Creek:

Dead wood Creek Birch Creek

Fairbanks

$10 a day, no board

$8 a day, no board; $6 to $8 a day, no board, is average.

$10 a day, no board, general wages.

$5 and board .

$14 a day, no board; some $6 and board; some $10 and board.

$12, no board;

Some claims on Cleary Creek.

Some claims on Creek.

some $8 and board.

$6 and board

Summer, $5 a day and board; winter, $2.50 a day and board.

Summer, $5 a day and board ; winter, $3 a day with board.

$5 and board

$180 to $200 a

Council

$10 a day and board.

$7. 50 and board.

month and board.

Solomon

Kugruk

$6 a day and board .

$5 and board ; some at $100 per month.

$5 a day and board; $8 without board.

212 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

LUMBER AND FUEXu

Timber.

The areal distribution of timber in Alaska does not by any means coincide with that of the placer gold. The South Coast region, in which there are extensive forests/ does not contain the most extensive alluvial gold deposits. The Juneau, Porcupine, and Sunrise districts are the only placer-gold fields developed within the area of heavy timber. In these three districts the large timber may be taken advantage of for local use. Under present conditions of transportation, however, this coastal timber forms no more of an asset in the consideration of the interior and the Seward Peninsula placer fields than as if it did not exist.

Spruce is commonly the timber on which the gold miner of the interior has to rely. It is very poor, both for fuel and for lumber, and in steam-producing quality a cord is the equivalent of not more than 700 pounds of Pennsylvania bituminous coal. The diameter of the spruce of the interior Yukon Valley rarely exceeds 18 inches, and. averages 10 inches. The timber line varies from 2,000 to 3,000 feet above the sea, and many of the low- lying river valle}7s are fairly well forested.- In the Tanana Valley and its tributaries near Fairbanks is found an exceptionally good growth of spruce timber, up to 18 inches in diameter, while birch, aspen, and cottonwood occur in less amount.

In the Fortymile district spruce trees up to 18 inches in diameter occur, but in general the growth does not differ from that found along the Yukon and Tanana bottoms.

At the head of the Tanana and White rivers the timber line reaches 3,000 feet, and there is a fairly good growth of spruce, birch, aspen, and cottonwood. The Kuskokwim and Koyukuk River valleys are also timbered with spruce.

The Sunrise and Chisna districts, which are nearer to the coastal strip than the regions mentioned above are better supplied with timber, spruce from 18 to 24 inches being common.

Those portions of Seward Peninsula which have attained importance from a placer-mining standpoint possess no timber except stunted willows. All mining operations must therefore depend on a foreign supply.

The prices for lumber in table 15 are for native or imported lumber, according to the timber resources of the district. In general all the interior camps make use of the native lumber. One of the difficulties experienced is to get good clear bottom boards for sluice boxes.

Sawmills are in operation at all the principal centers, Atlin, Dawson, White Horse, and Fairbanks. At Central House in the Birch Creek

a Brooks, A. H., The geography and geology of Alaska: Prof. Paper U. S. Geol. Survey No. — (in preparation), forestry map, PI. — .

purington] LUMBER AND FUEL. 213

district a sawmill was formerly in operation, but has been abandoned. At Fairbanks, in the summer of 1904, two sawmills with a total daily capacity of 25,000 board feet were in operation.

Timber fires are frequent in the interior and are sometimes very destructive in dry seasons. There being no system of policing the forests for purposes of fire protection, the probability is that an increasingly large amount of timber will, as the population increases, be annually destroyed by fire.

Coal.

Though there are extensive a coal fields in Alaska, practically none of them have been exploited. Much of the coal is of a lignitic character, but some very good bituminous coals have been found. In the South Coast province good coal occurs 20 miles from the coast near Controller Bay6 and in the Matanuska basin c 50 miles from the head of Cook Inlet. Neither of these fields are yet within reach of transportation. Lignitic coals are present at many localities along the Pacific coast, but these, too, are undeveloped.

In the interior coal has been mined along the Yukon, but has not yet furnished a local fuel supply. The Yukon d coals include the lignite beds of the upper river and a better grade of bituminous coals which outcrop along the Yukon below Nulato. Lignite coal has also been found along the Koyukuk and on the Cantwell, a southern tributary of the Tanana. Though these coals may in the future furnish fuel for placer-mining operations they are an unknown factor.

Lignite has been found in the eastern part of Seward Peninsula, but its commercial value is unproved. A small mine has, however, been in operation in the Fairhaven district near Kotzebue Sound,6 and has found a ready market for its output, which is of a Hgnitic character.

Near Cape Lisburne, 200 miles north of Nome/ bituminous coal occurs in commercial quantities, but has not yet been mined to any extent. It is still an open question whether it can compete with the imported coals.

The fuel question in Alaska may take a new phase with the introduction of gas-producing engines, for these lignites are found to be very effective power producers.

The following brief statement concerning recent? tests with the gas producer at the United States Geological Survey coal-testing plant,

a Brooks, A. H., The coal resources of Alaska: Twenty-second Ann. Kept. U. S. Geol. Survey, pt. 3, 1901, pp. 515-571.

b Martin, G. C, Petroleum fields of Alaska and Bering River coal fields: Bull. U. S. Geol. Survey No. 225, pp. 371-376.

cStone, R. W., Coal resources of southwestern Alaska: Bull. U. S. Geol. Survey No. 259, pp. 151-171.

d Collier, A. J ., The coal resources of the Yukon: Bull. U. S. Geol. Survey No. 218.

eMoffit, F. H., The Fairhaven gold placers, Seward Peninsula, Alaska: Bull. U. S. Geol. Survey No. 251, p. 67.

/ Collier, A. J., Coal fields of the Cape Lisburne region: Bull. U. S. Geol. Survey No. 259, pp. 172-185.

214 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

St. Louis, has been courteously furnished for this report by Mr. Marius R. Campbell:

The results of tests made during the past season at the United States Geological Survey coal-testing plant at the Louisiana Purchase Exposition at St. Louis proved conclusively that producer gas of such a quality that it may be used directly in a gas engine can be made from bituminous coals and lignites as well as from the highly carbonized fuels, such as anthracite, coke, charcoal, and wood, that alone have been used in the past for this purpose, and strange as it may appear, the lignites and lignitic coals have yielded better results than those ordinarily classed as bituminous. This means that the low-grade coals of the western half of the United States may have a value for the production of power equal to that of the best West Virginia coal as it is used at the present time.

The equipment by which these results were obtained consists of a Taylor gas producer with economizer, scrubber, tar extractor, purifier, and gas holder, furnished by R. D. Wood & Co., of Philadelphia, and a gas engine of 235 B. H. P., furnished by the Westinghouse Machine Company, of Pittsburg. The great difficulty in the past in using bituminous coals in the producer has been the extraction of the tarry matter from the gas. With the above equipment the tar and sulphur in the gas is almost completely removed, so that these substances give little or no trouble in the gas engine.

It appears, then, that the interior must for the present depend for fuel on its timber resources, such as they are. The camps of Seward Peninsula will probably adopt crude oil as the most economical fuel if the price can be brought down to $2 a barrel delivered at Nome. There appears to be a need at Nome and some of the other large camps of an oil-tank and pipe-line system by which the oil can be cheaply transferred from steamers, stored, and pumped to the various producing creeks adjacent to the coast. The native spruce timber will afford a fuel supply to the region east of Niukluk River, if gold discoveries are made there.

For any of the camps in the South Coast region there is an abundant supply of fuel, as wood may be had for the cutting, and coal can be had at a comparatively low cost.

Purington.]

Lumber And Fuel.

Table 15. — Cost of firewood awl flume lumber in Alaskan camps, including Dawson, Yukon Territory, and Atlin, British Columbia.

Fuel.

Lumber per M,

planed on one side

unless otherwise

stated.

Juneau district:

Windfall Creek

$10. 00

Gold Creek

12. 50-15. 00

Chisna district:

Headwaters of Copper River

Slate Creek

Daisy Creek

Nizina district:

Chititu Creek

Copper Creek

Dan Creek

Sunrise district:

Crow Creek

25. 00-35. 00

Resurrection Creek

Porcupine district:

Porcupine Creek

McKinley and McCoon creeks

Atlin district:

Pine Creek . .

40. 00-50. 00

Boulder Creek

Spruce wood, $7 cord

40. 00-50. 00

McKee Creek

35. 00-40. 00

Birch Creek

35. 00-40. 00

Dawson district:

Bonanza Creek

Eldorado Creek

Spruce wood, $15 cord..

70. 00-90. 00

Gold Run

Spruce wood, $11.50cord .

70. 00-100. 00

Sulphur Creek

Upper Dominion Creek

Hunker Creek

Spruce wood, $11 cord..

60. 00-90. 00

Wade Creek

a 175. 00

Walker Fork

a 100. 00

Chicken Creek

200. 00-250. 00

Eagle district:

American Creek .

a 75. 00

Discovery Fork

Rampart district:

Gold Run Creek

a Rough.

216 GEAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Table 15. — Cost of firewood and flume lumber in Alaskan camps, etc. — C*itinued.

Fuel.

Lumber per M,

planed on one side

unless otherwise

stated.

Circle district:

Dead wood Creek

Spruce wood, $12 cord..

$100. 00-125. 00

Independence Creek

Mastodon Creek

Mammoth Creek

Eagle Creek

Spruce wood, $10 cord..

Miller Creek

Woodchopper Creek

Fairbanks district:

Fairbanks Creek

Spruce wood, $10 cord..

220. 00-250. 00

Cleary Creek

Chatham Creek

Spruce wood, $10 cord.. Spruce wood, $7 cord. . .

Pedro Creek

100. 00-150. 00

Gold Stream

Nome district:

Anvil Creek

Bituminous coal from $17 to $30 per ton.

Crude oil at Nome, $3 per barrel.

Gasoline distillate at Nome, $3.50 per 10- gallon case.

Wood, $12 cord on the Niukluk River.

/ 50. 00

Dexter Creek

50. 00-60. 00

Glacier Creek

50. 00-60. 00

Bourbon Creek t

Dry Creek

Peluk Creek

' 50. 00

Basin Creek

Council district:

Ophir Creek

60. 00-100. 00

Melsing Creek

Crooked Creek

Solomon district:

Solomon River

Kassan Creek . .

Kougarok district:

Homestake Creek

Fairhaven district:

Candle Creek

100.00-150.00

Inmachuck River

Kugruk River

Port Clarence district:

Anikovik River

Gold Run

Buck Creek

"Rough.

purington.] GRAVEL AND PLACER MINING IN ALASKA. 217

Roads And Road Building In Alaska.

Introduction.

The means of getting- from one part of the Territory to another and from the various towns and supply points to their tributary mining camps are very bad. The data concerning road construction, which were courteously furnished me officers of the Canadian government based on Klondike experience, indicate that road building on an extensive scale is entirely feasible in the northern latitudes, and that roads can be constructed and maintained at moderate cost. In all probability Alaska is worse equipped with those improvements which contribute to progress and prosperity than any other area of like size lying in the domain of a civilized people.

Highway construction in Alaska is of the highest importance to the development of the Territory. The product of the gold-bearing gravels which have been already exploited is sufficient to support a considerable number of persons and to maintain towns of important size. The gold mining which has been done in the interior of Alaska has been conducted in spite of difficulties of transportation which would hardly be credible were they not substantiated figures obtained in parts of the Territory from responsible men.

It must not be assumed that the ordinary miner of Alaska is of a provident disposition. Many men of great energy, to whom is due the credit of having developed and opened large portions of this hostile country, are little disposed to take care for the future; yet they possess pluck and determination which is deserving of the highest praise. Outside of geologic and topographic exploration and making of excellent maps, and the furnishing of postal and telegraphic service, the miner, until the present session of Congress (1905), has been very little assisted.

An act of Congress was passed April 27, 1901, authorizing the appointment of road overseers and the creation of road districts in the Territory of Alaska, but this proving impracticable after a year's trial Congress has met the urgent demands for road building by the recent enactment of a statute which in two of its sections provides for the limited building and maintenance of wagon roads and trails.0 Following are the first two sections of the said act:

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That all moneys derived from and collected for liquor licenses, occupation, or trade licenses outside of the incorporated towns in the district of Alaska shall be deposited in the Treasury Department of the United States, there to remain as a separate and distinct fund, to be known as the ; 'Alaska fund," and to be wholly devoted to the purposes hereinafter stated in the district of Alaska.

aAn act to provide for the construction and maintenance of roads, the establishment and maintenance of schools, and the care and support of insane persons, in the district of Alaska, and for other purposes.

218 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

One-fourth of said fund, or so much thereof as may be necessary, shall be devoted to the establishment and maintenance of public schools in said district; five per centum of said fund shall be devoted to the care and maintenance of insane persons in said district, or so much of said five per centum as may be needed; and all the residue of said fund shall be devoted to the construction and maintenance of wagon roads, bridges, and trails in said district.

Sec. 2. That there shall be a board of road commissioners in said district, to be composed of an engineer officer of the United States Army, to be detailed and appointed by the Secretary of War, and two other officers of that part of the army stationed in said district, and to be designated by the Secretary of War. The said engineer officer shall during the term of said detail and appointment abide in said district. The said board shall have the power and it shall be iheir duty, upon their own motion or upon petition, to locate, lay out, construct, and maintain wagon roads and pack trails from any point on the navigable waters of said district to any town, mining or other industrial camp or settlement, or between any such town, camps, or settlements therein, if in their judgment such roads or trails are needed and will be of permanent value for the development of the district; but no such road or trail shall be constructed to any town, camp, or settlement which is wholly transitory or of no substantial value or importance for mining, trade, agriculture, or manufacturing purposes. The said board shall prepare maps, plans, and specifications of every road or trail they may locate and lay out, and whenever more than five thousand dollars in i he aggregate shall have been expended on the construction of any road or trail, contract for the work shall be let by them to the lowest responsible bidder, upon sealed bids, after due notice, under rules and regulations to be prescribed by the. Secretary of War. The board may reject any bid if they deem the same unreasonably high, or if they find that there is a combination among bidders. In case no responsible and reasonable bid can be secured, then the work may be carried on with material and men procured and hired by the board. The engineer officer of the board shall in all cases supervise the work of construction and see that the same is properly performed. As soon as any road laid out by the board has been constructed and completed they shall examine the same and make a full, detailed report of the work done on the same to the Secretary of War, and in such report they shall state whether the road or trail has been completed conformable to the maps, plans, and specifications of the same. It shall be the duty of said board, as far as practicable, to keep in proper repair all roads and trails constructed under their supervision, and the same rules as to the manner in which the work of repair shall be done, whether by contract or otherwise, shall govern as in the case of the original construction of the road or trail. The cost and expenses of laying out, constructing, and repairing such roads and trails shall be paid by the Secretary of the Treasury out of the road and trail portion of said " Alaska fund " upon vouchers approved and certified by said board. The Secretary of the Treasury shall, at the end of each month, send by mail to each of the members of said board a statement of the amount available of said "Alaska fund" for the construction and repair of roads and trails, and no greater liability for construction or repair shall at any time be incurred by said board than the money available therefor at that time in said fund. The members of said board shall, in addition to their salaries, be entitled to receive their actual traveling expenses paid or incurred by them in the performance of their duties as members of said board.

It will be of interest to state that during the twelve months ending June 30, 1904, the total amount collected from license fees outside of incorporated towns was $145,043.65. a

MacLennan, M. F., Receipts and disbursements of the United States for the fiscal year ending June 30, 1904, Treasury Department, p. 14.

Purington.1 Roads And Road Building In Alaska. 219

As a little less than three-fourths of this amount is available for roads, it is evident that the work can not be pushed very rapidly.

It is probable that not more than 40 miles of standard road could be built and maintained in any one year in the central Yukon province, and not more than 20 miles of standard road in the South Coast province. Moreover, it is not likely that the fund will increase rapidly, as the number of incorporated towns is growing.

Though a beginning was made in the construction of a military horse trail from Valdez over Thompson Pass, the project was only partially successful on account of lack of funds for maintenance.

The recommendation of Mr. Alfred H. Brooks, of the Geological Survey, of an appropriation of $1,000,000 to be spent for wagon roads in Alaska is amply justified by the necessities of the case. It is probable that for this sum 900 miles of roads (300 of the Dawson standard wagon type and 600 for sleds) could be built in those parts of the country which would be most assisted by their construction. Provision should, however, be made for their annual maintenance. The inhabitants of Alaska would be as appreciative of such Federal aid as those of any portion of the American possessions, and, by such improvement in transportation facilities, the annual Alaskan product in gold would be greatly increased.

A serious detriment to the making of a road in Alaska is the thawing of the ground beneath the moss. It has been the universal experience that wherever the moss is cut into thawing immediately commences, and the trail which was passable becomes a filthy, slimy mass of mud, roots, and broken stones, a difficult route for men on foot, a slow and tiresome road for loaded animals, and an impassable obstacle to any sort of vehicle. In regions farther south, under temperate conditions, trails frequently are developed into fair wagon roads by much usage. Such developments can never take place in any part of the Northwest.

In the Northwest, where the ground is always subject to slight disturbances from alternate freezing and thawing, the roads can not be as durably constructed as in portions of the United States where similar topographic conditions prevail. The table of expenses furnished by the Canadian government for this report shows that the cost of maintenance does not exceed 15 per cent of the original mile-cost of the road. A feature that can not be too strongly impressed on those who have never seen the interior of Alaskan country is the extraordinary difference between the topography of the southeast coast, which is most often visited by tourists, and the portions of the country in which the rich placer deposits have been developed. In the coast region about Juneau, Admiralty and Baranoff islands, and in Prince William Sound (see PI. XYI, A, p. 114) the needle-like peaks, precipitous slopes, cataracts in summer, avalanches in winter, and all the

220 GRAVEL AND PLACER MINING IN ALASKA. [bull.263.

formidable conditions characterizing an alpine district make road building very costly. There is much rock work, and expensive bridges, trestles, and culverts are necessary. The cost of the wagon road from Juneau into Silver Bow basin was $3,750 a mile, and that of the wagon road built in 1898 from Skagway to the summit of the White Pass was $6,000 per mile. Compare this with the Yukon-Tanana gold district. In the vicinity of Fairbanks 13 miles of passable wagon trail, over what is known as the Ridge Trail going to the creeks, have been built at a cost of less than $100 per mile. This road (see PI. XXX VIII, A) was made through a stretch of birch and aspen timber; the trees were cut out and many of the stumps removed; no ditch was made along the sides and the road was wide enough for only one wagon. But it is passable, and freight rates have already been reduced from 25 and 30 cents per pound to 10 and 15 cents.

It may be objected that transportation sufficient to meet the needs of the miner can be accomplished in winter when the freight rates are very much cheaper. This is far from being the case. The winter transportation itself would be greatly assisted by good roads on which sleds of 1 and 5 ton capacity could travel. As to winter freighting, it may be stated that in the winter of 1903 a man contracted to transport a boiler weighing 5,600 pounds from the town of Fairbanks to Pedro Creek, a distance of 20 miles, for $2,000, and lost $300.

Furthermore, 75 per cent of the work of exploiting the gold-bearing gravels is carried on in the four months of the open season, and then the miners are in need of the bulk of their supplies. In summer the prices of commodities in the towns are frequently lower than in winter. The period during which supplies for the winter are generally brought in is from August 1 to September 1.

Cost And Method Of Constructing Highways.

Considered from a highway standpoint, Alaska, owing to its varying topography and natural conditions, may be divided into three provinces — the South Coast province, the central Yukon province, and the Seward Peninsula province. Opportunity was had to inspect the excellent wagon roads which have been built in the northwest portion of Canada by the Canadian government. The figures courteously given by the officers of the Canadian department of public works relative to the cost of highway construction in the Yukon Territory are considered representative of the probable cost of such construction in the central Yukon province of Alaska. This and other information is embodied in table 16, and portions of it are elaborated in the succeeding paragraphs. The object of the table is to show, in a form easy for comparison, the costs of road building in the Northwest as exemplified by and estimated from previous experience.

So low a cost would not have been possible had not teamsters hauled all necessary supplies gratis.

U. S. Geological Survey

Bulletin No. 263 Pl. Xxxviii

A. Road In Fairbanks District.

B. Road In Atlin District, British Columbia.

Purington.]

Roads And Road Building In Alaska.

The portions of Alaska represented by Alaska Peninsula and neighboring- islands, and the Copper River basin, north of Prince William Sound, have not been especially considered, as there appears to be no present need there of expensive routes of communication. In general it may be said, however, that the cost of construction in Alaska Peninsula is the same as in Seward Peninsula, and the cost in the Copper River basin the same as in the central Yukon province.

Table 16. — Cost of road construction.

Locality.

Authority.

Construction, cost per mile.

Annual maintenance, cost per mile.

Notes.

South Coast province:

Juneau

Private constructors.

do

$3, 750

6,000

300-1, 000

1, 500-3, 300

3, 000-4, 000

6,000 1,200-3,000

Good road built

S k a g w a y — White Pass.

British Columbia:

Atlin

Yukon Territory:

Dawson and vicinity.

Do .

under great topographic difficulties.

Road no longer used.

Good roads easily

B. C. Atlin, gold commissioner.

Canadian department of public works of Yukon Territory.

do

$350

built, very little corduroy.

Standard highways constructed as described below.

Sled or winter

Seward Peninsula:

Nome and vicinity.

Do

Estimates based on cost of railways already constructed,

Private railway enterprises now in operation.

Estimate based on work done by Canadian government in Yukon Territory.

...do

trails; rarely used in summer.

Standard highways constructed as described below.

Railway — 3-foot

Central Yukon:

Tanana, Birch Creek, and Koyukuk districts.

Do

gauge, 20-pound rail, 2,600 ties to mile.

Standard highways constructed as described below.

Sled or winter

trails.

222 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

South Coast Province.

Wagon roads, while extremely useful in this portion of Alaska, cost so much that it is not likely they will be built except as heretofore, by private enterprise, to accommodate individual mining properties or groups of mines. The province is likely to prove in the future, as it has proved in the past, more important from the standpoint of quartz mining than of alluvial mining. The construction of roads is none the less desirable on this account, and should any large area capable of producing mineral be found at a point remote from the coast, a highway to it over which freight could be handled all the year round would be highly desirable. Winter conditions are exceedingly severe in the higher mountains. In the construction of the White Pass and Yukon Railway, 110 miles in length, 1,500 men were employed for twentysix months. Train service is maintained throughout the winter under considerable difficulty, both heav} winds and heavity drifted snow being frequently encountered. Rotaiy snow plows have to be run daily, encountering drifts from 15 to 35 feet in depth. The average cost of handling snow for a season is $75,000. Characteristic South Coast province topography is illustrated by PI. XVI, A, p. 114.

Atlin District And Yukon Territory.

In the Atlin district of British Columbia, which was visited during the present investigation, the topography is comparatively favorable to road construction, and it will be noticed from the table that the cost is low. PI. XXXVIII, B, p. 220, shows a characteristic view of an Atlin road.

The Yukon Territory of Canada offers the most instructive lesson in practical highway construction in the north, and affords a striking contrast in this respect to the adjacent American domain. The officers of the department of public works of the Yukon Territoiy, notably Mr. S. A. D. Bertrand, the superintendent, and Mr. W. Thibaudeau, the Territorial engineer, were kind enough to place at my disposal the data relative to the building and maintenance of the public roads. The following summary can not fail to be of interest in this connection:

The longest road in the Territory is from Dawson to White Pass, 342 miles. Its history dates from 1899.

Prior to 1899 all freight from Dawson was transported to the mining creeks by pack animals in summer, and sledded either with dogs or horses over the ice and snow in winter.

Purington.]

Roads And Road Building In Alaska.

The following table shows the wagon roads and sled roads constructed:

Boads constructed from 1899 to 1903.

Total.

Wagon roads

Miles.

So. 25

Miles.

Mih s.

Miles.

Sled roads

Amount expended from 1899 to 1903 in constructing and maintaining roads and bridges in Yukon Territory, Canada.

1899 $50, 000. 00

1900 205, 609. 72

1901 147, 174. 90

1902 228, 543. 88

1903 398, 789. 95

Total 1, 030, 118. 45

Average cost of construction for wagon road was $1,500 to $3,300 per mile. Average cost of construction for sled or winter trail was $250 to $350 per mile. The cost of repair and maintenance of wagon roads was $350 per mile per annum. The cost of repair and maintenance of sled roads was $25 per mile per annum.

The following comparative statement shows transportation charges, per 100 pounds between Dawson and a few of the important mining centers in 1899, previous to the construction of the wagon roads, and in 1904. The improved condition means a direct benefit to the miners of at least 600 per cent on all supplies and machinery freighted by wagons over first-class roads:

Transportation charges, per 100 pounds, from Dawson to important mining centers in Yukon Territory, Canada.

From Dawson to —

Distance.

Grand Forks

Miles.

$7.00

$1.00

Gold Bottom

Caribou

Discovery Sulphur

Gold Run

224 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

The following is a statement of the localities served by wagon roads:

Localities served by wagon roads, with mileage, in Yukon Territory, Canada.

Miles.

Bonanza Creek 18. 00

Lovett Gulch 1. 50

Adams Gulch 1. 75

Eldorado Creek 7. 65

Calder Creek 5. 60

Gold Hill 50

Quartz Creek 5. 00

Indian River and Eureka Creek 18. 00

Hunker Creek 24. 35

Bear Creek 3. 00

Last Chance Creek 2. 50

Gold Bottom Creek 5. 40

Dominion Creek 16. 25

Sulphur Creek 9. 56

West Dawson 41

Henderson Creek 13. 00

Duncan Creek ( Stewart River district) 20. 00

Livingstons Creek (Big Salmon district) 16. 00

Copper King mines (White Horse district ) 4. 20

Grafter copper mine 5. 44

Ridge road and spurs to Grand Forks, Gold Bottom, Caribou, and Gold Run. 73. 70

Total 251. 81

Following is a statement of the localities served by sled roads:

Localities served by sled roads, with mileage, in Yukon Territory, Canada.

Miles.

Old River cut-off from Lake Labarge to Hutchi, cut out in 1899 160. 00

Dawson-White Horse, overland mail route 350. 00

Glacier-Miller Creek, Sixtymile district 58. 25

Bucher Creek, Sixtymile district 20. 00

Lepine Creek, quartz mines 14. 00

Lower Sulphur 8. 00

Last Chance (upper end) 3. 00

Lower Dominion 6. 00

Cut-offs, Stewart River 20. 00

Duncan Creek (upper part) 4. 00

Total 643. 25

Less Eureka end of Dawson-White Horse trail (covered into wagon road).. 17.00

The estimate for the amount required for maintenance of roads and bridges in the Yukon Territory for the year ending June 30, 1904, is $103,190.

The men employed in road construction are paid $5 and board per day of ten hours. A team of horses, used in scraping or carting, is reckoned at $25 per day, including wages of the driver, Foremen are paid $6 and board per day of ten hours,

U. S. Geological Survey

Bulletin No. 263 Pl.

pTF£

A. Ogilvie Bridge, Klondike River.

B. Six-Mule Team Drawing 8000 Pounds, Klondike.

purington.1 ROADS AND ROAD BUILDING IN ALASKA. 225

Several bridges of a permanent character have been built in the Territory, the principal of which is the Ogilvie steel bridge over Klondike River, the cost of which was $35,000. It is seen in PL XXXIX, A.

The method of constructing the road in the Yukon Territory, where frozen muck and gravel flats are traversed, is illustrated in fig. V.h This section was drawn from information furnished by Mr. W. Thibaudeau, Territorial engineer of the Yukon Territory. It has been the experience that over frozen ground this type of road, costing $3,200 per mile, can be maintained with much less expense than roads running along the hillsides. With roads of the kind here illustrated it has been found best to leave the moss intact under the bed of poles, for it protects the ground from thawing; the black frozen muck, having the consistency of solid stone, remains as a firm bed. The inside faces of the side ditches are not always banked with sod, but such banking affords additional protection. The ditches are cut either entirely

lVyf] Broken stone or grave/ D/M£A/S/OA/S

/6 feet across top ofroac/

Brush /aid crosswise

3 feet depth of ditch

6 inches depth of 'stone oryrare/

lol Pc/es /o/of fenyMmse / foot deptfy ofSrash

[\-cH moss 3 //7c/? es d'cm eter ofpofes

M Frozen muck pjT|] frozen y ray ei

Fig. 49. — Method of constructing road over frozen muck, Klondike.

in muck or partly in muck and partly in underlying gravel. These conditions vary with the thickness of the muck.

On the other hand, when the moss blanket is cut into, as is necessarily the case in all side-hill cutting, the sun and the seepage water gradually thaw the frozen muck, which becomes a soft, slimy mass. The cost of maintenance of such roads has been found so much greater than that of roads on flat ground that the latter are now constructed,, even if the distance between terminal points is greater.

PI. XXXIX, B, shows a 6-mule team hauling 8,000 pounds with a trailer on an upgrade stretch of road in Hunker Creek, near Dawson. PI. XL, A (p. 226), from a photograph taken in August, 1904, shows a 6-horseteam endeavoring to haul a load of 3,300 pounds from Fairbanks, on Tanana River, to Cleary Creek, in the Fairbanks district of Alaska. Not half a mile from the point where this picture was taken, on the road to Cleary Creek, a cart bearing a L5-horsepower boiler was seen broken down, its wheels buried in mud and water. Bull. 263—05 15

226 GRAVEL AND PLACER MINING IN ALASKA. [bull. 268.

Two miles from the town of White Horse, Yukon Territory, on the road to the copper deposits, is an excellent stretch of corduroy road extending* over a marshy piece of unfrozen ground. The 6-inch timbers used for lagging have all been flattened on the upper side for a width of 15 feet in the central portion, so that a rough wagon track is formed. Thus a much evener wear on the lagging is maintained than would be the case if the timbers were left in their original round condition.

Central Yukon Province.

Mr. Alfred H. Brooks, in his article entitled "Placer Mining in Alaska in 1903," a has suggested the following routes for Government roads in the central Yukon province of Alaska:

(1) A road from Eagle to the Tanana, the Chistochina, and to Valdez, on the coast, a distance of approximately 400 miles. This probably should follow the present well-established trail, which is used as winter and summer mail route. The most important part of the road would be that between Eagle and the camps of the Fortymile region. An alternate route would be to Fairbanks, on the Tanana, from Copper River by way of the Delta River valley, a distance of about 300 miles. (2) A road to extend from Circle, on the Yukon, through the Birch Creek and Fairbanks district to the Tanana, a distance of about 150 miles. (3) Rampart, on the Yukon, to be connected with the mouth of Baker Creek, on the Tanana, by a road which would open up the Minook and Baker districts, a distance of less than 50 miles. (4) A hundred miles or so of road to be built in the Koyukuk region to connect the goldbearing creeks with the head of steamboat navigation on Koyukuk River. It is believed that these roads would form a system of .main arteries by which most of the placer fields could easily be reached, and that the production- of the mines would thereby be so much increased as to fully justify the expense.

Well-constructed roads following the above routes would result in making freight rates in the placer districts which the roads would traverse one-fourth less than at present. The operations in the Birch Creek and New Fairbanks placer districts, for example, are directly dependent on prices of supplies laid down on the claims. The pay streaks in the broad creek valleys frequently become wider and wider as freight rates become lower. Such a statement would appear absurd if applied to regions where the charge for freighting represents only a small percentage of the original cost of the commodities. Where, however, the cost of material, especially machinery, is rendered double or more by freight charges, transportation facilities become a highly important factor in considering whether a given piece of ground is or is not workable. Prices for mining supplies in the town of Fairbanks, the supply point for the new gold-placer region on tributaries of Tanana River, are by no means cheap. As compared with prices on the claims which lie from 15 to 25 miles inland, however, they are

a Bull. U. S. Geol. Survey No. 225, 1904, p. 57.

U. S. Geological Survey

Bulletin No. 263 Pl. Xl

A. Six-Horse Team Drawing 3,300 Pounds, Cleary Creek, Fairbanks.

B. Creek Topography, Fairbanks District.

>urington.] ROADS AND ROAD BUILDING IN ALASKA. 227

strikingly low. For example, a hundred feet of 8-inch 16-gage rydraulic riveted steel pipe costs in Fairbanks $175. On Fairbanks Jreek, 20 miles away, the same 100 feet of pipe, with freight at 20 ?ents per pound, costs, if transported in summer, $301, representing a :right charge of $126. In the Klondike, where the topography is learly the same, the same pipe would be landed on a claim 20 miles Tom Dawson for a freight charge of $9.45.

Anything worse than the present condition of the trails in the nterior of Alaska is difficult to conceive. Men ignorant of the use of i map and compass are frequently lost in the vast maze of rolling mountains and undergo hardship and starvation. It is a curious fact, lependent on the peculiar frozen conditions, that the great river flats, vhere the present trails are at their worst, are the very places where agon roads of the Dawson type can be most easily maintained. As :or the hill country, the roads can, in many cases, be led almost continlously for distances of from 5 to 20 miles along the crests of gently oiling divides.

PI. XL, B, shows one of the important producing creeks of central alaska, where a road is badly needed, and PI. XLI, A, illustrates the present mode of transportation in that district.

Seward Peninsula Province.

In the central and western portions of Seward Peninsula, namely, he Nome, Solomon, Council, Topkok, Kougarok, Teller, and York districts, any projects of installation of roads must take into account ;he entire absence of native timber. The region so defined is the one vhich has attained importance as a gold-producing area, while the eastern portion of the province, where scant growth of spruce does >ccur, is not at present productive. PI. XLII illustrates typical Reward Peninsula topography.

Owing to these conditions wagon-road construction which employs he use of timber in any form will be expensive, and as seen b}r the able given previously in this paper, the cost of building the narrowrage railways which have done excellent service in Seward Peninsula is $6,000 per mile, exclusive of rolling stock, while a wagon road )f the Dawson type will rarely fall below $1,000 per mile. The rates or hauling on these railways may be reckoned at $1 per ton per mile, n summer, wagons with broad tires now haul freight over roads which lave, as it were, made themselves, at rates of $1.50 to $3 per ton per uile, varying according to the nature of the country traversed.

It is questionable whether wagon roads, extensively built and ,iming at permanency, will ever be constructed in Seward Peninsula o supply the needs of the gold-mining communities. The Nome

228 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Arctic Railway, from Nome to Anvil Creek, 12 miles long, the ties of which are laid for a portion of its length on a 2-inch plank bed, appears to serve a useful purpose. Only seventy days were consumed in the construction of the 12 miles. The Wild Goose Railway, also of 3-foot gage, from Council to Ophir Creek, has been constructed in a similar manner. Sixteen miles of a standard-gage railway, the Council City and Solomon River Railway, have also been completed. Considering the comparative cheapness with which railway material can be hauled at various points in Seward Peninsula, it is likely that short lines of railway will continue to be built by private enterprise to supply the several inland mining communities.

The suggestion is here made that narrow-gage pole tramways laid over the tundra might in some cases be used in parts of Seward Peninsula for long hauls. They would be expensive to construct and maintain, but would not, of course, compete with winter transportation.

In view of the small cost of narrow-gage railways in Seward Peninsula and the small annual maintenance cost, as compared with what it would probably cost to maintain wagon roads, the Federal Government should aid in tramway rather than wagon-road construction in that portion of Alaska. The light industrial railways now manufactured by various firms could be constructed with special modifications for the tundra country, and could be shipped, knocked down, to different portions of the peninsula.

In conclusion, I would say that of the three provinces of Alaska above specified, the central Yukon province is most in need of Federal aid for highway construction. By this means placer districts now lying idle could be made to support a numerous population, and it is doubtful whether any other form of assistance would prove as beneficial as stimulating prospecting for new placer fields.

Freight Rates.

Freight Rates From The States.

The present freight and passenger rates from Tacoma, Seattle, and San Francisco to the main supply points of Alaska accessible by oceangoing steamers are given in table 17 (pp. 230-231).

Freight rates are fairly constant from year to year, but passenger rates vary from one season to another, according as the different steamship companies are competing or temporarily combined. Return passenger rates majr be reckoned at generally 25 per cent higher than north bound, but occasionally rise to 100 per cent higher. During 1904 the return rates from Nome were double those outgoing. It

U. S. Geological Survey

Ulletin No. 263 Pl. Xli

A. Pack Train, Birch Creek District.

B. Trestled Flume In Eagle District.

purington.] ROADS AND ROAD BUILDING IN ALASKA." 229

should be noted also that the return rates are higher on the last steamers than on those returning early in the season.

Service is maintained all the year round, with the exception of the Seward Peninsula service, St. Michael, and points far up Cook Inlet. Between these points and Seattle, service can be reckoned on from May 15 to October 15 only.

Gravel And Placer Mining In Alaska.

[Bull. 263.

Table 17. — Ocean freight and passenger rates for 1904 from

25

03 O

Oi o

02 o

m 0

o o

Cjo

So"

.

o

Pi-O

c ft

bc

'55 bo

Sbed

53 &o-

"1

. a

-fi

-p

o"rt SR .

>Vh

P bog

.2

!3©p

5j3

§i.sa

o £ o

00

0 £ 0

Oo

0 ©

03 £ P,

aj ? P,

cd

j

S

£

S

Pe?" to?*.

Per tow.

Per ton.

$9.00

$11.00

$14. 00

$18. 00

$22. 00

Special contract.

Ju

do... do...

Se He

do... do... do... do...

do... $50 and

/St. Michael

higher.

a

do... do...

o

I-H

do...

$60 and higher.

p

Teller

York

do... do...

Bluff

k

Coal is shipped from different points to Alaska, and the local price is given in tables for different Alaska towns.

Coal in sacks per ton, 2,240 pounds, Seattle to St. Michael or Nome, $12.

Freight and passenger rates from San Francisco to any of the above points do not exceed 5 per cem above Seattle rates.

The winter passenger trip between Seattle and Nome, via White Pass and Dawson, includes steamer, rail, horse-stage, and dog-sled travel, consumes three months, and costs about $1,000.

Freight Rates.

Seattle to Alaska coast points, including lightening when necessary.

to sj

3 a

Oss

Per ton.

$8.00

$10. 00-

n

Per M ft- $9.00

12.50- 1(

Paton.

$24. 20

Per

tun.

$11.00

Per

ton.

$6.20

Freight rates from Seattle or San Francisco vary from $10 to $15 per ton of 40 cubic feet. There is no classification.

Per

head.

$30.00

! 60.00

Per

head.

$5.00

Passengers.

$20. 00

$15. 00

$25. 00-

55. 00-! 90. 00,

Return freights

Ore and concentrates not exceeding $100 per ton value.

Per ton.

$4.00

Per

ton.

$3.50

Per ton.

$3.00

$5.00

$7. 50- lG. 00

7. So-

232 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

In table 18 are given the through freight and passenger rates from San Francisco or Seattle to Dawson, in Yukon Territory, and to Eagle, Circle, Fort Gibbon, and Fairbanks, in Alaska, via the White Pass route.

Table 19 gives the through rates from San Francisco or Seattle to the above-named points, via St. Michael and Yukon and Tanana rivers.

While during the open or summer season the all-water transport of freight via St. Michael is cheaper, the river steamboat service has not yet been developed to a sufficient extent to insure prompt and regular delivery. Should the Tanana gold fields prove important, however, the all-water route will probably be the one most practical for the transportation of supplies. It has the additional recommendation that by means of it the crossing and recrossing of the Canadian frontier is avoided. On the other hand, via the White Pass route, freight can be landed at Fairbanks much earlier than via the all-water St. Michael route.

It should be stated, in the consideration of table 18, that the White Pass and Yukon Railway has established three classifications of freight for through shipments, the regular rates for which, on less than 10 shipments from Seattle to Dawson for the summer season, are as follows:

Class A, including mining tools and articles bulky and not easily destructible, $65 per ton.

Class B, including more fragile articles, $80 per ton.

Class C, including small supplies, $95 per ton.

Shippers should remember that a package containing any article coming under a higher class than that comprising the bulk of thepackage is charged at the highest rate. This applies also to unspecified packages.

A list of mining supplies, on which a special reduction is made for transport from Seattle to Dawson between July 1 and August 15, is given following table 18.

The winter freight rates, via the White Pass route, exceeding $560 per ton from Seattle to Dawson need not be considered, as they are; prohibitive, except in emergency cases. This route necessitates a haulage of nearly 300 miles by sleds.

Pukington.]

Freight Kates.

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234 GRAVEL AKD PLACER MINING IN ALASKA. [bull.263. '

The following rates from Seattle to Dawson, via the White Pass route, on commodities especially applicable to placer mining, are also given for summer traffic between July 1 and August 15:

Freight rates from Seattle to Dawson, via White Pass route, from July 1 to August 15.

Lumber, rough (including flume lumber or lumber dressed on one side

only) per M feet. . $48. 75

Oats and feed, in straight or mixed carloads per ton. . 55. 00 1

Hay ( compressed to at least 22 pounds per cubic foot ) 7 tons or over do 52. 50

Blacksmith-' s coal, 20,000 pounds and over do 47. 50j

Coal oil, 20,000 pounds and over do 47. 50]

Candles, 20,000 pounds and over do 55. 00 i

Nails, horseshoes, bolts, nuts, and spikes, 20,000 pounds and over do 47. 50

Flour, 20,000 pounds and over do 52. 00

Beef in barrels do 62.50,

Iron and iron articles: Angle, band, bar, boiler, rod, hoop, sheet and galvanized iron, sheet steel, T rails, wire rope, bolts, anvils, nuts, nails, chains,

per ton 52. 00

Hardware supplies: Asbestos cement, asphaltum, axle grease, bags and bagging, cement, clay (fire), handles, oil (lubricating in cases), pulleys, iron pumps (hand), rope and cordage, tar, tin plate, varnish, wheelbarrows,

per ton 55. 00

Table 19. — Through freight and passenger tariff for 1904, between San Francisco, Seattle, and Yukon, Koyukuk, and Tanana River points, via St. Michael.

Anvik

Nulato

Koyukuk mouth

Fort Gibbon

Fairbanks

Rampart

Fort Yukon

Circle

Eagle

Fortymile

Bergman

Bettles

North bound.

Passengers.

First

$103. 00

Second class.

$70. 00

Freight per ton of 2,000 pounds, or 40 cubic feet, ship's option. ™

South bound.

Passengers.

$40. 00

$97. 00

Second class.

$66. 00

Freight per ton

of 2,000 pounds,

or 40 cubic feet,

ship's option.

$35. 00

Purington.]

Freight Rates.

Heavy pieces. — On shipments to and from all river points, single pieces or packages weighing between 750 and 1,000 pounds, add 20 per cent; between 1,000 and 1,500 pounds, 30 per cent; between 1,500 and 2,000 pounds, add 40 per cent; between 2,000 and 3,000 pounds, add 60 per cent; between 3,000 and 4,000 pounds, add 80 per cent; between 4,000 and 5,000 pounds, double rate; over 5,000 pounds taken only by special contract.

Local Freight And Passenger Tariffs.

Table 20. — Freight arid passenger rates, for 1904, via river steamer from Dawson to points on Yukon and Tanana rivers. Return rates from 10 to 30 per cent higher.

Da wson to —

Fortymile, 53 miles . . .

Eagle, 102 miles

Circle, 292 miles

Fort Yukon, 377 miles.

Rampart, 620 miles

Fairbanks, 1,000 miles. Fort Gibbon, 700 miles

Nulato, 991 miles

Anvik, 1,196 miles

St. Michael, 1,601 miles

Freight per

ton of 40 cubic feet or 2,000 pounds.

$10. 00

Passengers.

First class.

$7.00

Second class.

$5.00

Lumber, one and one-half the above rates per 1,000 feet B. M. Horses and cattle, 1 to 5, one and one-half the above rates for each head; 6 to 10, one and one-quarter rate each head; over 10, one rate each head.

See footnote table 19 in regard to shipment of heavy pieces.

Table 21. — Local passenger and freight tariff on Tanana River.

Passenger Tariff.

Upstream.

Downstream.

From — To—

o

u

cj M as PQ

s

o3

a

A o

w M PI

,Q

'3

From— To—

O

Jo

o

H

M

Cj

O)

O

Cj

$25

d

a

H

Miles from Tanana. . .

$30

$40

Miles from Fairbanks

$15

$20

Tanana

$20

$25

Fairbanks

Chena

$5

$25

Baker Creek

Tolovana . .

Neenana

Tolovana

Chena

Baker Creek

Gravel And Placer Mining In Alaska.

[Bull. 263.

Table 21. — Local passenger and freight tariff on Tanana River — Continued.

FREIGHT TARIFF. a

Upstream.

Downstream.

From — To-

M

Cd M O U

M o3

n

O

o

En

a

oi a

O

Os

a

o3

'3

From— To—

o

pi

o o

U

O

M

o3

w

a

Miles from Tanana. . .

$20

$25

$35

Miles from Fairbanks

Tanana

$45

Fairbanks

Chena

$15

$20

$25

$30

Baker Creek

Neenana

?5

Neenana

Tolovana

?0

Baker Creek

n Per ton of 2,000 pounds, or 40 cubic feet, ship's option. Table 22. — Local passenger tariff on Koyukuk River, season 1904.

Upstream.

From— To—

s o

a

M

©

K 'So

ft

s

ft

'3

Ph

$?4

s

bo

o

w

$34

d

o

Pl,

p)

M

o

$44

o

$48

n

$51

s

pj

$54

Ph

$60

Pq

Miles from Nulato

Nulato

$5

$16

$18

$66

Koyukuk mouth

3?

4?

Dagitli Biver

Dulbi River

M

Seattle Point

Hog River

Rock Island Point

?,H

Red Mountain

?4

Bergman

?0

Allen River

Peavy

purington.] FREIGHT RATES.

Table 22. — Local passenger tariff on Koyukuk River, season 1904 — Continued

Downstream.

From— To—

d ®

a

Pq

$10

d

'3 d

O

-a

$15

d Ph -d a ta

M a o

$20

(-1

0)

s

w

$26

J5

'0

Pm

"S

$34

$38

0)

S

ft

$40

d

a

d

fed

$50

Bettles

$5

$9

$51

Peavv

Allen River

Bergman

Red Mountain

Rock Island Point

Hog River

flfi

Seattle Point

Dulbi River

Dagitli River

1?

Koyukuk mouth

Table 23. — Packing rates per 100 pounds from Rampart, Alaska, to various points

in 1904-

Hunter Creek

[Little Minook Creek

i Hoosier Creek

[Ruby Creek

[jSlate Creek

(Over divide to Pioneer Glen, Rhode Island, Omega I and Thanksgiving creeks

Distance.

Milrs.

25 to 32

Winter.a

$2.00

Summer.

$4.00

a It should be said in regard to winter transportation that horses are gradually replacing dogs in |all parts of Alaska. The dog is theoretically cheaper to feed than the horse. He gives more trouble, is more likely to give out on the trail, and experience has shown that in regions where horse feed can be obtained, and where much sledding is done, horses are cheaper.

Circle- Fairbanks packing rates. — The town of Circle, being the nearest point on Yukon River to the placer districts of Birch Creek and Fairbanks, has some importance, especially in winter, as a distributing center for those districts. The rates for packing in summer by horses and in winter by dog sleds from Circle are given in table 24.

238 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Table 24. — Packing rates per 100 pounds from Circle to various points.

Summer.

Dead wood Creek

Eagle Creek

Fairbanks Ci eek

Fairbanks

Fort Gibbon to Cleary Creek.

Distance.

Winter.

Miles.

$3.00

$25. 00

Packing rates at Fairbanks. — These summer rates are continually being reduced as the trails are improved, but the following may be regarded as those that will obtain in 1905:

Table 25. — Packing rates per 100 pounds from Fairbanks to various points.

Summer.

Pedro Creek

Chatham Creek

Cleary Creek

Upper Fairbanks Creek Lower Fairbanks Creek

Distance.

Winter.

Miles.

$2.00

$10. 00

In the summer of 1904 six-horse teams were engaged in hauling loads not exceeding tons from Fairbanks to the creeks. The conditions under which this hauling was done may be seen from PI. XL.

The nearest American supply point to the creeks of the Fortymile region is Eagle, but this town, on account of its remoteness and the absence of good roads, is at present of only subordinate importance to the miners. Dawson, although in Canadian territory, is a more convenient place to procure supplies. These are bought generally in the fall and freighted to the creeks on sleds with dogs or horses during the winter, either by way of Sixtymile Creek or Fortymile Creek. In the summer freight is carried by pack train from Eagle or by boats from the Yukon up Fortymile Creek. The winter rates from Eagle in 1903 averaged about $5 per 100 pounds; the summer rates about $25.

Freighting to the new placer district of the Porcupine is done by wagon haul across Chilkat River to Portage Point, thence to Klukwan in canoes, which are poled upstream, sometimes under great difficulties. From Klukwan the supplies are hauled up the Klehini, 15 miles, to the town of Porcupine. The rate from Haines Mission to : Porcupine is $3.50 per 100 pounds, and to Pleasant Camp, 6 miles beyond Porcupine, it is $5 per 100 pounds.

purington.] FREIGHT RATES. 239

Freight for the Chistochina district must be packed on horses from Valdez, via the military road to the Chistochina, and then up the river. The rate in 1903 was, in summer, $10 per 100 pounds, and in winter $3.50 per 100 pounds.

A railway has been projected from Resurrection Bay on the Alaska coast up the Sushitna and down the valley of Cantwell River to the Tanana, thence across to the Yukon at Rampart. A few miles of the road have actually been constructed from the Resurrection Bay terminus. There is little doubt that a railway following either this route or one following the already surveyed route from Yaldez to Tanana Crossing would pay as an investment. The benefit of such lines of railway to the south interior portion of Alaska, including the Hope and Sunrise, Chistochina, and Fairbanks placer districts, is unquestionable.

Freight rates from Hope and Sunrise to the mining creeks in the vicinity are as follows:

Supplies are freighted from Sunrise to Mills Creek, about 18 miles, for 5 cents per pound.

From Sunrise to Lynx Creek, between 20 and 25 miles, for about the same. This is contract work.

Supplies are boated from Sunrise to mouth of Glacier Creek (7 to 8 miles) and there packed to Crow Creek (6 to 7 miles) for 3 to 3£ cents, but this is b}' private yearly contract. The miners usually bring their own supplies over the snow in the winter time so that there is not much freighting.

The transportation of supplies from supply points on Seward Peninsula to the mining creeks is done mainly by hauling in wagons; in some cases, as from Cheenik to Council, by flatboat, and in three cases, Nome-Anvil Creek, Solomon-East Fork, and Council Number 15, Ophir Creek, by railway. Between points on the coast the summer transportation depends on small ocean-going boats, for the most part Igasoline launches, whose trips are not regular, as landings at Nome, iSolomon, Bluff, and York depend on the weather. All supplies larger than those which can be transported in dories must be lightered at the labove-named points. Charges for lightening at Nome are included in [table 26. It should be understood that the ocean rates to Seward Peninsula points given in table 17 include the charge for lightening in jevery case.

The wagon haul is fairly easy at some times of the year in the broad, gravel-filled river beds. These streams are subject to flood, however, and such teaming is impossible at times. From White Mountain, on Fish River, to Council, Ophir Creek, Gold Bottom, and as far as Goose iCreek, on the Casadepaga, a useful type of flatboat, drawrn by a strong ihorse, draws 5 tons during favorable conditions of water. Such hauljing, when possible, reduces the freight over the wagon haul by about 40

Gravel And Placer Mining In Alaska.

[Bull. 263.

per cent. Such horse boats can ascend the Casadepaga only during June and early July.

The freight rates from Teller to the creeks of the Kougarok district were not available in detail for this report. Freighting by wagon haul is, however, carried on from Teller, York, and some of the other more distant coast points of Seward Peninsula, and the rates may be figured as higher than at Nome in proportion to the increased cost of supplies at those coast points.

On Ophir Creek, in the Council district, it has been shown that the larger companies can reckon on obtaining their supplies direct from San Francisco via ocean steamer to Cheenik; flat steamers, Cheenik to mouth of the Niukluk; horse boat, Niukluk mouth to Council, and railway from Council to the creek, at a cost of approximately 2 cents a pound in excess of San Francisco prices. Table 26 gives the local freight rates from the main suppl}7 points to the creeks.

Table 26. — Summer local freight and passenger rates from Nome to various points in]

Seward Peninsida, 1904-

Point.

Method of transportation.

General freight.

Lumber.

Horses

and

cattle.

Passengers.

Solomon a

Steamer

do

Per ton.

$15. 00

$10. 00-15. 00

5. 00-10. 00

10. 00-15. 00

30. 00-40. 00

Per Mft.

$22. 50

Per head.

$18.00 22.50,

$7.50

Cheenik

do

Council

Teller

Steamer and flatboat.

Steamer

do

Kiwalik

. do

Deering

do

Anvil Creek

Wagon haul, railway. c

Wagon haul

do..

Cooper Gulch

Moonlight Gulch

Bourbon Creek

do

Dry Creek

Hoi yoke Creek

do

Dexter Creek

Buster Creek

..do

Lillian Creek.

do

Osborne Creek . .

do

Seattle Creek. .

Washington Creek

do.

Moss Gulch Creek

do

a No harbor. feNome to Lanes landing via Kuzitrin River, $50 per ton, c Wagon haul, IHon rates.

Purington.]

Freight Rates.

Table 26. — Summer local freight and passenger rates from Nome to various points in Seward Peninsula, 1904 — Continued.

Point.

Method of transportation.

General freight.

Lumber.

Borses

and cattle.

Passengers.

Peluk Creek

Wagon haul

do

Per ton.

$5. 00-10. 00

10. 00-15. 00

20. 00-30. 00

40. 00-50. 00

Per M/t.

Per head.

Otter Creek

Martin Creek

Glacier Creek

Rock Creek

do

Prospect Creek

do

Lind bloom Creek

do

Alpine Creek

do

Sledge Creek

do

Bolto Creek

do

Bangor Creek

Twin Mountain Creek .

do

Pioneer Creek

do

Last Chance

Penny River

Willow Creek

do

Oregon Creek

do

Nugget Creek

Cripple River

Nome River, head . .

do

Fountain Creek

do

East Fork Solomon to

Stage line

$12. 50

Council.

Rates for lightening cargo at Nome.

General merchandise, including small machinery per ton. . $5. 00

Machinery:

Two- to three-ton pieces

Three- to four-ton pieces

Four- to five-ton pieces

Five- to six-ton pieces

Six- to seven-ton pieces

Seven- to eight-ton pieces

Double-compressed hay

: Coal in sacks

; Coal put on beach and piled up

Lumber per M

Live stock per

Winter freighting, by means of horse and dog sleds, may be reckoned at about one-half the summer hauling rates. Bull. 263—05 16

do

K). 00

do

I feet..

head. .

242 GKAVEL AND PLACER MINING IN ALASKA. [bull.263.

From Nome to Council, 85 miles, winter haul is —

Warm-storage rate, per ton $60. 00

Cold-storage rate, per ton 40. 00

Passenger rate, forty hours 15. 00

Summer local freight rates from Solomon to various points.

Per ton.

Mouth Shovel Creek $8. 00-$12. 00

Hurrah Creek 10. 00

Willow Creek 90. 00

Ruby Creek 80. 00

Mystery Creek 15. 00

West Creek 12.50

East Fork Creek 15. 00

Down coast to Spruce Creek 12. 50

Summer local freight rates from Council to various points.

Per ton.

No. 15, Ophir Creek (railway) $10. 00

Gold Bottom (horse boat) 30. 00

Gold Bottom ( wagon haul) 50. 00

Lower Casadepaga 75. 00

Customs Regulations.

Considerable delay and confusion have been caused in the past by shippers not understanding the requirements of the United States and Dominion customs departments. The following information is given for the guidance of shippers, and the instructions herein contained must be strictly adhered to:

Shipments of goods from United States ports via Skagway, destined to Eagle City and other lower Yukon River points in transit through British Columbia and Yukon Territory, must be accompanied by 4 certified copies of invoices and 2 copies of bills of lading. All of these papers are necessary for customs purposes at Skagway.

Goods shipped from United States ports, destined to points in Alaska via Skagway and Yukon River, are bonded through Canadian territory duty free.

Charges for preparing customs papers by the customs agent of the White Pass and Yukon route will be as follows: For preparing shipper's manifest, 50 cents; transportation and exportation entries will be charged for on basis of actual cost to the White Pass and Yukon route.

The customs agent will notify the agent of the White Pass and Yukon route at Skagway station of the amounts to be assessed on above account, and the same will be placed against each shipment as a back charge.

a Under exceptionally favorable conditions large lots have been landed San Francisco-Little Hurrah Creek as low as $17 per ton.

purington.] CUSTOMS REGULATIONS. 243

Difficulties of a peculiar nature are experienced by the placer miners of interior Alaska owing to the configuration of the international boundary between the Territory of Alaska and the British possessions. The town of Dawson, being the largest settlement of the interior, is naturally the point where mining supplies are most easily and quickly obtained by the placer miners of the neighboring American camps of Birch Creek and Fortymile, the Rampart district, and others of the Yukon and Tanana. During the season of 1904 the rapid and to a certain extent justifiable development of the town of Fairbanks, on Tanana River, gave promise that this settlement would eventually become as well equipped to supply the needs of the Tanana miners as is Dawson. The American Yukon camps must, however, for a considerable number of years be locally dependent on Dawson as a source of supplies.

Theoretically the miners are supposed to buy their mining supplies and machinery either at points in the United States or at towns on the Yukon in American territory. Such supplies, of course, if shipped down the Yukon, come through the Canadian territory in bond free of duty. In practice, however, owing to the necessity of obtaining supplies quickly, purchases are made in Dawson, and unless the supplies can be proved to be returned American goods the American miner must pay duties to the United States custom-house at Eagle according to the rates given in the following list. Frequently duties must be paid even on supplies made in the United States and returned, since there is no manufacturer's mark by which the customs inspector can identify them. This especially applies to such important mining supplies as small parts of boilers, tubes, pipe, pipe fittings, elbows, T's, unions, grate bars, sledges, drill steel, picks, shovels, pump plungers, buckets, valves, small car wheels, strap iron, rails, bar and rod iron, and small castings. Even larger pieces, such as parts of lrydraulie giants, are frequently unstamped. These supplies, sept for sale by the machinery firms of Dawson, frequently pay customs duties both to Canada and the United States before reaching the Alaska camps. Dawson is frequently sought by the American bfiiners in the midst of the short season for the purpose of repairs to various mining machinery, it being the only place accessible on the Yukon where machine shops exist. It may easily be seen how burdensome on the miner is the imposing of a duty on his machinery which he brings back into American territory after repairs, and on which he must pay a duty because it has been improved or changed in foreign territory.

Gravel And Placer Mining In Alaska.

[Bull. 263.

Below are given the United States customs duties on small mining supplies:

United States customs duties.

Articles.

Duty.

Boilers and engines, first and second hand

Points (steam), sluice forks, picks, shovels, axes

Sledges

Drill steel

Hydraulic hose

Cast pipe

Hydraulic pipe

Gas pipe

Rubber hose

Coke

Bituminous coal

Dynamite

Black powder

Qaps

Fuse

Candles

Nails, wire

Nails, wrought iron

Steel rails

Wire cable

Centrifugal pumps

Sawed lumber

Wheelbarrows, iron

Rope

Self-dumping carriers

Asphalt coating

Hydraulic giants .

Lubricating oils

Copper plates

Cement

Quicksilver

Iron castings

Iron castings, ground and fitted

45 per cent ad valorem. 45 per cent ad valorem. 1J cents per pound. 4.7 cents per pound. 20 cents per pound. 4.7 cents per pound. 2 cents per pound. 35 per cent ad valorem. 30 per cent ad valorem. 25 per cent ad valorem. 67 cents per ton. 6 cents per pound.

6 cents per pound. $2.36 per thousand.

45 per cent ad valorem.

25 per cent ad valorem.

One-half cent per pound.

cents per pound.

Seven-twentieths cent per pound.

1 cent per pound and 40 per cent ad valorem.

45 per cent ad valorem.

$2 per thousand and 50 cents for each side dressed.

45 per cent ad valorem.

1 cent per pound.

45 per cent ad valorem.

$3 per ton.

45 per cent ad valorem.

25 per cent ad valorem.

cents per pound.

8 cents per 100 pounds.

7 cents per pound. Eight-tenths cent per pound. 45 per cent ad valorem.

purington.] TELEGKAPH RATES. 245

It should be stated that there is a duty on all horses, cattle, sheep, and dogsa entering- Alaska. Thus a dog team coming down river from Dawson in the winter is dutiable.

During the season of 1904 a United States customs inspector accompanied the Yukon steamers from Dawson with shipments from that point to Fairbanks, in order to obviate the long delays which had previously been necessary for appraisement at Eagle.

Owing to the export duty on gold which is charged by the Canadian government, some difficulties have been experienced by Americans who bring gold mined in Alaska Territory through Canadian territory, via Dawson, en route to the United States. The Canadian government naturally assumes that all gold found on south-bound passengers leaving Canadian territory at White Pass has been mined in Canada. Such gold is therefore liable to confiscation by the officers in charge of collection of royalty unless the bearer is provided with a properly ratified certificate stating that the gold is of foreign production. American miners should obtain such a certificate at Pagle from the United States authorities (fee, 10 cents) and have the same ratified at Dawson by the Canadian police (fee, 50 cents for gold from 1 to 25 ounces, $1 for 25 ounces and upward). All individuals leaving Yukon Territory for United States territory are strictly searched for gold.

The regulations in regard to boats coming down the Yukon into United States territory must also be taken into consideration. No boat or scow, not a regular carrier, can, for example, make the journey from Dawson to Circle, carrying over 5 tons of freight. This is especially burdensome on settlers who wish to outfit at Dawson and float their goods down the Yukon. The situation, owing to the conditions, is undoubtedly a burden of extra expense on the miner, but is unavoidable, and must be reckoned with in estimate of expenses attending the prosecution of placer mining in the Alaska interior.

Telegraph Rates.

means of the United States military telegraph line in Alaska, including the wireless system from St. Michael to Port Safety and the Seattle-Sitka-Valdez cable with connection to Juneau and Skagway, an all-American service is now maintained from all important points of Alaska (except Circle) to the outside world.

The rates for the military service in Alaska are based upon a tariff of 2 cents per word for each 100 miles or fraction thereof, address and signature not counted, a message of less than 10 words being charged for as a 10-word message. During the month of September, 1904, a

aHorses, value $150 or less, $30 per head; over S1">0, 25 per cent ad valorem. Dogs, 20 per cent ad valorem; cattle, $2 per head, under 1 year old; others, 27 1 per cent ad valorem.

Gravel And Placer Mining In Alaska.

[Bull. 263.

cable line was completed between Sitka and Valdez, which, with the Sitka-Seattle cable, completes the American telegraph service to all parts of Alaska. Through 10-word rates from Seattle are as follows:

Telegraph rates from Seattle to points in Alaska.

Sitka $2. 50

Juneau 2. 75

Skagway 3. 00

Valdez 3. 50

Nome 4. 00

Eagle 3. 00

Rampart 3. 50

Fairbanks 3. 50

Distances And Cost Of Supplies.

Tables Nos. 27, 28, and 29 give approximate distances in Alaska. Table 27. — Distances, in miles, between towns in Alaska, excluding Seward Peninsula.

N

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Co

a

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O

M

o3

'6

E

1,880

1,140

1,268

1,423

1,300 1,720 1,543 1,783 1,848

2, 003

1,458 1,325 1,275 1,227

St. Michael . .

1,900

1,249

1,049

r 1,204

I &920

1,075 1,208 1,253 1,298

Fort Gibbon

Fairbanks

Circle

Eagle

Fortymile

Dawson

a 35 cents each additional word.

& Taking trail at Circle.

By trail.

purington.1 DISTANCES. 247

Table 28. — Distances, in miles, between points on Seward Peninsula.

Nome.

Cheenik.

Coun-

Bluff.

Solomon.

Teller.

York.

Kewa-

lik.

Blossom.

Cheenik

Council

Bluff

Solomon

411)

Teller

York

Kiwalik

Blossom

Candle

Table 29. — Distances from main supply points in Alaska to neighboring creeks.

From Circle.

Miles.

Diggings on Deadwood Creek 40

Mouth of Boulder Creek 35

Junction of Mastodon and Independence creeks 47

Mouth of Miller Creek 45

Junction of Mastodon Fork and Eagle Creek 53£

From Fairbanks.

Gilmore at crossing of trail 14

Junction of Twin and Pedro creeks 18

Junction of Wolf and Cleary creeks 24

Fairbanks Creek at mouth of Alder Gulch 27

From Nome.

Discovery on Anvil Creek 4

No. 3 above on Glacier Creek 7 j

Junction of Grass Gulch and Dexter Creek 7

Cooper Gulch 4

Bourbon Creek (passes through Nome).

Holyoke Creek

Dexter Creek 7

Buster Creek 9

Lillian Creek 11

Osborne Creek 7

Seattle Creek 22

Washington Creek 6

Moss Gulch 6£

Peluk Creek 2

Otter Creek

Martin Creek

Rock Creek

Prospect Creek 12

Lindebloom Creek 11

Alpha Creek 11 J

248 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Miles.

Sledge Creek.1. 13

Balto Creek 12J

Bangor Creek 17

Twin Mountain Creek 15

Last Chance Creek 20

Penny River 11

Willow Creek 10

Oregon Creek 19

Nugget Creek 18

From Solomon.

Mouth of Shovel Creek 5

Mouth of Kasson Creek 10

Mouth of Big Hurrah Creek 8£

Mouth of East Fork 11

Mouth of Coal Creek 15

Head of Ruby Creek (Casadepaga drainage) 20

Head of Penelope Creek (Casadepaga drainage) 21

Mouth of Goose Creek (Casadepaga drainage) 25

From Council.

Mouth of Ophir Creek

Mouth of Dutch Creek 8

Mouth of Crooked Creek 11

Mouth of Basin Creek 2

Junction of Gold Bottom and Warm Creek 8

Mouth of Mystery Creek 4

From Teller.

Bering Creek 13

Mouth of Right Fork of Bluestone River 15

Mouth of Alder Creek 17

Mouth of Ruby Creek 13

Mouth of Sunset Creek 3£

Marys Igloo 50

From Marys Igloo.

Quartz Creek 24

Angeles Creek 33

Goodall Creek 43

Homestake Creek 52

Macklin Creek 56

North Fork of Kougarok River 21

Harris Creek 20

Mouth of Baldy Creek 20

Mouth of Portage Creek 22

Purington.]

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Gravel And Placer Mining In Alaska.

[Bull. 263.

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[Bull. 263.

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[bull. 268.

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ptkington] GRAVEL AND PLACER MINING IN ALASKA. 255

IjEGAL CONDITIONS IN 1904.

Introduction.

After an investigation of the present conditions in the new so-called Fairbanks district of Alaska, situated on Tanana River, I was forcibly impressed with the urgent need of a change in the present location law, which allows the location of placer tracts by representation. An individual holding twenty or fifty powers of attorney from other citizens of the United States may go alone into a wild and unknown district and, by staking claims, each of 20 acres, tie up whole creek valleys which are by this process withdrawn from the area of public lands for a period generally amounting to eighteen months.

The location of the claims is then recorded in the nearest recording office in the names of the men who may be in San Francisco, Chicago, or New York. The ownership of the claims may afterwards be changed ad libitum by the passing of quitclaim deeds. The locator can have, under the law, but one claim by right of location on each creek; but by exercising the right of representation he withdraws from the public domain as many miles of creek beds as he can traverse and stake. On each claim he is required to do no work, beyond sinking a small discovery shaft, for the remainder of the year in which the location is made and up to the end of the ensuing year. Thus in any placer district in which the auriferous gravels have an economic value, and into which prospectors are continually pouring, as in the new Fairbanks district, many bona fide miners willing to search for gold to the extent of their physical and financial resources are rendered powerless through circumstances which they can in no way control or by any possibility foresee.

These men, willing to undergo the discomforts of an inhospitable country, either find themselves idle in a remote community, where living is expensive, or are compelled to make journeys of four or five days1 duration from the base of supplies, and pack their provisions, blankets, and tools on their backs to find ground that has not been staked.

It may be objected that each man has an equal opportunity to reach a given piece of ground first. This, however, is hardly the case. The resources of the men who unite to send an individual to locate for them by power of attorney are generally greater than those of the individual who singly goes out with the purpose of locating one claim for his own operations. The power-of -attorney man, equipped with a better outfit and very likely dogs or horses, can go farther and stay longer than the prospector of limited resources.

a I have discussed at some length the legal conditions of mining and the abuses prevailing under the present law in Alaska in a report made to the "Public Lands Commission " recently appointed by the President. In the same report I have embodied suggestions for a revision of the present law as far as it pertains to placer mines in Alaska.

256 GEAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Furthermore, the man who locates for others, if he does not represent persons living altogether at a distance, is frequently sent out by men whose interests are entirely inimical to the proper development of the region — namely, saloon keepers, nonproducers, "tin horns" (gamblers), or other riffraff such as are generally found in the new American mining camp. They have rarely the intention of operating the claims located in their names and thus producing gold. They hold the claims in the hope that the camp will boom, that inexperienced outsiders will come in, and that in the ensuing excitement they may sell at a figure based on the supposed value of the unprospected ground.

In the Fairbanks district portions of 3-mile stretches on three creeks are producing gold. Other portions within this producing area, as well as lengths of from 3 to 10 miles on six other creeks, are hardly prospected, are not producing, and are entirely withdrawn at present from exploration or exploitation through the process of the empowered staking above referred to. It is estimated that 2,000 persons will spend the winter in the district. Of these at least 1,200 will be ablebodied workingmen. The operations will afford work for possibly 600 men. One-half the remainder at least would prospect and develop new territory were it not for the nearly insuperable difficulties. The provisions of the present location law are, in my opinion, largely responsible for these difficulties.

In the portion of the Alaska interior lying between Yukon and Tanana rivers the auriferous gravels occupy a wide area. The overcoming of the purely physical obstacles to exploration is arduous, and many miles of creek valleys will be located as means of communication become established. If this large area and other areas yet to be explored are allowed to be progressively withdrawn from possible gold production, the result will be a distinct detriment to the development of Alaska.

A confirmation of the annoying and injurious effects of the law is afforded by the early history of the Nome gold district of Seward Peninsula, where the conditions were as follows:

Nearly every individual located not only for himself but also for his many friends by power of attorney. To such an extent was the power of attorney here abused that more than 7,000 acres of ground were located, so that the several thousand Americans who arrived later, finding no unstaked ground anywhere in the vicinity, justly raised a somewhat bitter complaint.

The practice of exercising the power of attorney is increasing in Alaska at present, and its abuse warrants the summary suspension of it if this be possible.

In September I visited the principal creeks on which gold-mining operations are being prosecuted in the Nome, Solomon, and Council

aSchrader, F. C, and Brooks, A. H., Preliminary Report on the Cape Nome Gold Region, U. S. Geou Survey, 1900, p. 32.

purington.] LEGAL CONDITIONS LN 1904. 257

districts of Seward Peninsula. Although the investigation of the legal conditions pertaining to gold mining was not called for by my instructions, certain facts regarding these conditions were impressed upon me. Indeed, it is impossible for an observer, impartially disposed, to go about the mining districts of Seward Peninsula and not seriously question the applicability of the present location law to Alaska conditions.

It is true that $100 worth of work is by law actually required on each 20 acres, but the statute is so loosely framed that the $100 worth of work is now done universally on each L60 acres, not only in Alaska but in all parts of the United States where placer mining is conducted. Moreover 1 have observed that this $100 worth of assessment work in all mining territory is little more than a farce. The suggestion that $100 on each 20-acre tract be used in making survey and plat of the claim the first year is worthy of consideration.

Application Of The Present Mining Law To Alaska.

The following order of the Secretary of the Interior, dated ,)u\y 28, 1885 (Land Office Decisions, vol. 1, p. 128) extended the regulations of the General Land Office to Alaska.

In pursuance of the eighth section of the act of Congress, approved May 17, 1SS4, entitled "An act to provide a civil government for Alaska" (23 Stat., 24), it is hereby prescribed that the rules and regulations of the (General Land Office and Department of the Interior governing the administration of the mining laws of the United States he adopted for and extended to the district of Alaska, so far as the same maybe applicable.

It is evident that the various provisions in Revised Statutes, Title XXXII, chapter 6, defining the United States mining laws, apply fully to Alaska. .

Sec. 2329. Claims usually called placers, including all forms of deposit, except veins of quartz, or other rock in place, shall be subject to entry and patent under like circumstances and conditions as are provided for vein or lode claims.

Lindley on Mines says (vol. 1, sec. 432) that this has been construed to mean:

(1) That there must be a discovery upon which to base the location.

(2) The location must be marked upon the ground so that its boundaries can be readily traced.

Discovery.

According to the accepted interpretation of the law in the mining States of the United States, gold must be found on the ground in a discovery shaft before the claim can be validly held by Location.

That many of the Alaska locations are illegal may he judged from the fact that very often three men have staked from ton to twenty 160-acre tracts of placer ground within periods varying from twenty- Bull. 263—05 17

258 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

four to seventy-two hours. On every one of these tracts under the correct interpretation of the law, a shaft or drill hole at least 15 feet in depth would have been necessary in order to find one color of gold. Yet the same men have immediately recorded their staked ground as locations, swearing that they discovered gold. Lindley states (sec. 437): "The Land Department has uniformly held that discovery is essential in the case of placers, going so far at one time as to hold that such discovery was essential in each 20-acre tract within a location of 160 acres located by an association of persons." He further says: "Discovery is just as essential in case of placers as it is in lode locations."

The regulations of the General Land Office include the following:

No lode claim shall be located until after the discovery of a vein or lode (or in a placer of gold) within the limits of the claim, the object of which provision is evidently to prevent the appropriation of presumed mineral ground for speculative purposes to the exclusion of bona fide prospectors before sufficient work has been done to determine whether a vein or lode (of gold) really exists. a

The nonobservance of the above requirement, and, in fact, the impossibility under the present law of its enforcement is the cause of the very evil in Alaska which the law aims to avert. I regard the promiscuous location and illegal holding of land on which gold has not been discovered as one of the most serious detriments to Alaskan development.

Subsequent Annual Labor.

Regarding subsequent labor Lindley (sec. 024) makes the following statement:

While a timely resumption of work may prevent a relocation, the law contemplates that the labor or improvements, actual and valuable, to the amount of $100 in each year, computed from the 1st day of January next succeeding the date of location, should be performed in good faith. There is probably no single provision of the law which is evaded to a greater extent than this one. While, of course, there are many exceptions the average locator exhausts his ingenuity in attempting to avoid this plain and wholesome requirement. The courts are disposed to deal with these drones in the hive with much more leniency than they deserve. The statute is too frequently applied on sentimental lines. Forfeitures, say these tribunals, are odious, and in many cases the reluctance with which they enforce the law encourages rather than deters the systematic evasion of it.

The statute is extremely liberal as to the time in which the specified amount of work shall be performed. A location made on January 1, 1897, may, in the absence of State laws or local rules requiring development work to be performed as an act of location, b be held without a stroke of labor until December 31, 1898, and in no case

a Mining laws and regulations, General Land Office, 1903, p. 27, §8.

'It should be borne in mind that the principal Western States where mining is conducted have, by State legislation, so enlarged upon the rather bare fabric of the Federal mining law that, within the boundaries of these States many of the abuses which are permissible under a liberal interpretation of the Federal law, have been done away with. On the other hand, the excellent restrictions in force in the placer-mining States have no force in Alaska, and in consequence decisions rendered by the courts must be much more liberal, and are productive of the evils for the obviation of which the State statutes were long ago enacted.— C W. P.

purington.] LEGAL CONDITIONS IN L904. 259

is the period less than a full year. It would seem that a more rigid enforcement of the rule would not only command more respect for the law, bul would in ;i greal degree tend to promote the general object and intent of the mining statutes — the development of the mining resources of the country.

The above quotations are made because the opinions so closely bear on the deplorable conditions in Alaska. The climatic conditions arc so formidable on the 81st of December of each year (the date of expiration of the time in which a miner may do his annual assessment work) that $100 might be expended by him in work on the claim in merely shoveling snow. Naturally, all traces of the work so done would be obliterated in a short time; yet it would be actual and valuable work, for otherwise he could not reach the ground beneath. This feature is so well understood in Alaska that a man who makes affidavit to work done holds his claim from year to year unquestioned, and it is undoubtedly true that the bulk of the territory held as placer ground is not onlyT unworked but unvisited by the claimants alter first location. Should, however, an individual relocate or "jump" a given claim so held, the first holder goes into court and swears that he has done his annual representation work, thus maintaining his title. Should the relocator maintain that he has searched the ground and found no traces of any previous work, he still has a weak case, and the verdict is usually against him. It is needless to say that this relocator has, in the great majority of cases, the better right to the ground.

I have endeavored to make clear a few of the reasons why the production of gold is actually retarded in Alaska, rather than assisted, by the present administration of the mining law.

Boundaries.

Of over a thousand prospectors in California, Oregon, Nevada, Colorado, Idaho, Montana, and Alaska whom I have known, talked with, and been in the field with, I have never seen ten who included a compass in their equipment, to say nothing of surveying instruments more nearly approaching precision. These men, generally known among themselves as "practical miners," are of the class by which mineral locations are generally made. Is it fair to assume that such men are competent to make a location which shall conform to the mining regulat ion

His location notice should give the course and distance as nearly as practicable from the discovery shaft on the claim to some permanent well-known points or objects, such, for instance, as stone monuments, blazed trees, the confluence of streams, point of intersection of well-known gulches, ravines, or roads, prominent buttes, hills, etc., which may be in the immediate vicinity, and which will serve to perpetuate and fix the locus of the claim and render it susceptible of identification from the description thereof given in the record of locations in the district, and should be duly recorded.

oU. S. Mining Laws and Regulations— General Land Office, 1903, p. 27, sec. 9.

260 GKAVEL AND PLACER MINING IN ALASKA. [bull. 263.

In Alaska, at least, the provisions called for by the above have become practically a dead letter, as is instanced by the case of the prospectors who during the season of 1903 were allowed to locate a group of claims defined as being on "Midas Creek, a tributary of a tributary of Koyukuk River." Midas Creek and the supposed locations afterwards proved to be entirely mythical.

The location law requires that the "location must be distinctly marked on the ground, so that its boundaries can be readily traced." How can the following decision of the Supreme Court of the United States, in the case of theMcKinley Creek Mining Co. v. Alaska United Mining Co.,a which sustained the validity of a placer location where no attempt was made to actually mark the boundaries, be reconciled with the above? Lindley says:

All that was done was to post notices on a snag or stump in a creek, claiming a certain number of feet running with the creek, and 300 feet on each side of the center of the creek, and referring to the claim as "the east extension of a certain-named claim and the west extension of another." Unless some facts or circumstances were represented to the court which can not be gleaned from the official report of the case, such a location would seem to fall short of the requirement that the claim shall be "distinctly marked on the ground, so that its boundaries may be readily traced."

I have no hesitation in saying that in Alaska, especially in Seward Peninsula, no attempt is ordinarily made by the locator to mark the boundaries of claims beyond the setting of stakes at the four corners averaging 3 feet in length by inches in diameter. These are generally overturned by the wind or uprooted by the frost within six months of the time of setting. And yet the burden of proof in case of subsequent dispute always rests on the relocator or the jumper.

I will call attention to the fact that the suggestions leading to modification in the present placer-mining law are directed to the reforming of the principal abuses which have been cited. Had time permitted, instances of abuse and misinterpretation of the present laws might have been indefinitely multiplied. Enough has been said to show that changes of a radical nature are needed in the laws and their administration, in order that the undoubted valuable mineral resources of Alaska may be exploited to the best advantage.

Much fault has been found in past years with the Territorial administration in the Klondike. That conditions affecting title have at times left much to be desired is undoubtedly true. At present efforts are being made to remedy\T the abuses which exist. In Alaska, on the other hand, each rich discovery of gold brings forth one or more lawsuits, and each new camp that is developed affords a profitable field of exploitation for swarms of parasites who, too indolent or too ignorant to devote themselves to bona fide mining, ingeniously strive, by manifold ways of trickery, to live by the labor of others.

a Cited by Lindley, sec. 373.

purington.] GRAVEL AND PLACER MINING IN ALASKA. 261

Bibliography.

The works consulted in the preparation of the present report, in addition to the files of technical journals, manuals, and catalogues relating- especially to placer mining, arc as follows:

Bowie, A. J., jr. A Practical Treatise on Hydraulic Mining. New York. L885, pp. 1-813. Illustrated.

British Columbia. Annual Report of Minister of Mines.

Brooks, Alfred H. Placer gold mining in Alaska in L902. In Bull. U. S. Gepl. Survey No. 213, 1903, pp. 41-4S.

Brooks, Alfred H. Placer mining in Alaska, 1903. In Bull. U. S. Geol. Survey No. 225, 1904, pp. 43-59.

Brooks, Alfred H. Placer mining in Alaska, 1904. In Bull. IT. S. Geol. Survey No. 259, 1905, pp. 13-31.

Brooks, Alfred H. A reconnaissance of the Cape Nome and adjacent gold fields of Seward Peninsula, Alaska, in 1900. Assisted by Richardson, G. B., and Collier, A. J. In a special publication of the United States Geological Survey entitled, Reconnaissances in the Cape Nome and Norton Bay Regions, Alaska, in 1900, pp. 1-180.

Collier, A. J. The Glenn Creek gold-mining district, Alaska. In Bull. V. S. Geol. Survey No. 213, 1903, pp. 49-56.

Collier, A. J. A reconnaissance of the northwestern portion of Seward Peninsula, Alaska. Prof. Paper U. S. Geol. Survey No. 2, 1902, pp. 1-70.

Collier, A. J. The gol 1 placer deposits of Seward Peninsula. Bull. U. S. Geol. Survey No. — . (In preparation.)

De Batv, R. Les gisements auriferes de Siberie. Paris, 1898.

Evans, George H. Practical Notes on Hydraulic Mining. San Francisco, 1897, pp. 1-48.

Fanning, J. T. A Treatise on Hydraulic Mining and Water Supply Engineering. New York, 1889, pp. 1-644. Illustrated.

Gwillim, J. C. Report on Atlin district. In Annual Report Geol. Survey, Canada, 1900, pp. 52-62.

Lev at, E. D. L'Or en Siberie orientale. Paris, 1897.

McConnel, R. G. Preliminary report of the Klondike gold fields, Yukon district, Canada. (Separate.) Geological Survey of Canada, 1900, pp. 1-44. (Map and illustrations. )

Mendenhall, W. C, and Schrader, F. C. The mineral resources of the Mount Wrangell district, Alaska. Prof. Paper U. S. Geol. Survey No. 15, 1903, pp. 1-71.

Moffit, Fred. H. The Fairhaven gold placers, Seward Peninsula, Alaska. Bull. U. S. Geol. Survey No. 247, 1905, pp. — .

Moffit, Fred. H. The gold fields of Kenai Peninsula, with a description of the coal fields of the Kachemak Bay region. Bull. U. S. Geol. Survey No. — . (In preparation. )

Moffit, Fred. H. The gold placers of Turnagain Arm. In Bull. IT. S. Geol. Survey No. 259, 1905, pp. 88-99.

New Zealand. Annual reports, Minister of Mines.

Poole, H. The Calorific Power of Fuels. New York, 1903, pp. 1-269. Illustrated.

Prindle, Louis M. The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska. Bull. U. S. Geol. Survey No. 251, 1905, pp. L-85.

Prindle, Louis M, and Hess, F. L. The Rampart placer region. In Bull. U. S. Geol. Survey No. 259, 1905, pp. 104-119.

Rose, T. K. The Metallurgy of Gold. London, 1898, pp. 1-514. Illustrated.

262 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263.

Schrader, F. C. Preliminary report on a reconnaissance along the Chandler and Koyukuk rivers, Alaska, in 1899. In Twenty-first Ann. Rept. II. S. Geol. Survey, pt. 2, 1900, pp. 441-486.

Schrader, F. C. A reconnaissance in northern Alaska across the Rocky Mountains, along Koyukuk, John, Anaktuvuk, and Colville rivers and the Arctic coast to Cape Lisburne, in 1901. Schrader, F. C, and Peters, W. J. Prof. Paper U. S. Geol. Survey No. 20, 1904, pp. 1-139.

Schrader, F. C, and Brooks, A. H. Preliminary Report on the Cape Nome Gold Region, Alaska; with maps and illustrations. 1900, 56 pp., 3 maps, and 19 plates. A special publication of the United States Geological Survey.

Smith, Hamilton, jr. Hydraulics, the Flow of Water through Orifices, over Weirs, and through Open Conduits and Pipes. New York, 1886, pp. 1-362. Illustrated.

Spencer, Arthur C. The Juneau gold belt. Bull. IT. S. Geol. Survey, No. — . (In preparation.)

State Mineralogist of California. Annual reports.

Stretch, R. H. Prospecting, Locating, and Valuing Mines. New York, 1900, pp. 1-372, with cuts.

Tove and Riazanof. Statistical Reports of the Amur Gold Region. St. Petersburg, 1902.

Van Wagenen, T. F. Manual of Hydraulic Mining. New York, 1880, pp. 1-95.

Whitney, J. D. The Auriferous Gravels of the Sierra Nevada of California. Cambridge, Mass., 1880, pp. 1-569.

Wright, C. W. The Porcupine placer district, Alaska. Bull. U. S. Geol. Survey No. 236, 1904, pp. 1-31. (Maps and illustrations.)

Index.

Page. A.

Abbe, Cleveland, jr., rainfall table compiled

by 43, 48

river tables compiled by 49

I Acknowledgments to those assisting 25 Alaska, map of 14 roads in 16, 217-228

views of 220, 226

Alaska-Treadwell Gold Mining Co., ditch

of 113-115

ditch of, plate showing 114

pressure box on, plate showing 116

investigation at mine of 13

Alden Creek, gold on, fineness of 204

Allenkaket, freight and passenger rates to

and from 236-237

Alluvial mining, definition of 26

Alpine Creek, freight and passenger rates

to 241

Amalgam, cleaning and retorting of 205

melting of 205-207

Amalgamated McKee Co., sluices of 143-144

American Creek, barite on 204

booming on, dam for, plate showing. . . 58

ditches on 105, 109

drainage basin of, figure showing 44

gold on, fineness of 208

investigation on 14

prospecting on, cost of 41

shoveling on, duty of man in 59

sluice boxes on, plate showing 56

stream conditions on 43-44, 52, 54

wood on, price of 215

American Gold Mining Co., ditch of 115

sluices of 142-143

Anglo-Klondike Mining Co., reservoir of. . . 127

Anikovik River, gold on, fineness of 209

wood on, price of 216

Anvik, freight and passenger rates to 233-235

ice at 49

rainfall at 48

stream conditions at 49

temperatures at 49

Anvil Creek, drifting on 86-87

freight and passenger rates to 240

gold on, fineness of 209

investigation on 14

prospecting on, cost of 42

reservoirs on 128

settling pond on, view of 128

shoveling on, duty of man in 59

Page.

Anvil Creek, sluicing on 56, 150, 191

steam shovel on 74, 77

figure and plate showing 74

stream conditions on 53-54

track and incline on 71-72

figure showing 71

wages on 71

wood on, price of 216

Anvil Mountains, mining in, methods of. . . 33

Assessment work, abuse of 257-259

Atlin, riffles at, view of 194

Atlin Creek, B. C, pipe line on, plate showing

Atlin district, B. C, bowlders in 141

ditches in 104, 107-108, 117-118

dredges and dredging in 160-162

view of 160

duty of miner's inch in 139

gold of, character of 145, 207

investigation in 13

mining in, methods of 28

pipe line in, view of 128, 132

prospecting in, cost of 41 .

protective dams in 146-147

roads in 221

view of 220

sluice box in, plate and figure showing 143,194

sluicing in 143-147

stream conditions in 52,54

wages in 211

wood in, price of 215

Australia, comparison of conditions in

Alaska and 30

B.

Baker Creek, gold on, fineness of 208

freight and passenger rates to 235-236

Bangor Creek, freight and passenger rates

to 241

Bank-head water, use of 138

Bannock, Mont., dredging at 175-176

Barite, occurrence of 204

Basin Creek, ditches on 106, 109

gold on, fineness of 209

sluicing on 150

stream conditions on 53

wood on, price of 216

Bear Creek, Alaska, gold on, fineness of ... 209

Bear Creek, Y. T., gold on, fineness of 208

investigation on 14

steam shovel on 78-80, 89

Index.

Page- Bear Creek, Y. T., steam shovel on, plate

showing 74

stream conditions on 52

Beaudette, A. J., information from 51

Bed rock, cleaning of 59-60, 78

Bed-rock sluice, view of 136

Bendeleben Mountains, location and altitude of 46

Bergman, freight and passenger rates to and

from 234, 236-237

Bertrand, S. A. D., information from 222

Bettles, freight and passenger rates to and

from 234,237

Bibliography 260-261

Big Hurrah Creek, gold on, fineness of 209

investigation on 14

stream conditions on 53

Birch, Stephen, information from 37,39

Birch Creek, Alaska, stream conditions on. 52

wages on 211

Birch Creek, B. C, ditches on 104, 107

gold on, fineness of 207

stream conditions on 52

wood on, price of 215

Birch Creek district, ditches in 105,109,119

drift mining in 87-88

hydraulic mining in 117

ice in 89

investigation in 14

map of 45

mining in, cost and methods of 28,

pack train in, view of 228

physical conditions in 32, 36, 89

prices in 249 254

prospecting in, cost of 41

roads in 221

rutile in 205

shoveling in, duty of man in 59

stream conditions in 45

topography of, plate showing 120

wages in 211

wood-fire thawing in 89-90

Black sand, occurrence of 204

Bluff, freight and passenger rates to . 230-231,240

Boats, use of 239-240

Bolto Creek, freight and passenger rates to. 241

Bonanza Creek, Y. T., black sand on 203-204

dam on, plate showing 126,148

ditches on 105, 108

drains and pumps on, relative cost of . . 58

dredges and dredging on 162-164

plates showing 162

gold on, fineness of 207

investigation on 14

prospecting in, cost of 42

shoveling on, duty of man in 59

sluices on 148

plate showing

. steam point thawing on 89

stream conditions on 52, 54

wood on, price of 215

Bonanza Gulch, gold on, fineness of 209

Booming, character and use of 57

cost of 38

dam for, plate showing 58

Bourbon Creek, dredging on 165

Page. Bourbon Creek, freight and passenger rates

to 240

stream conditions on 53

wood on, price of 216

Bowie,A. J., on hydraulic mining. 111-113,116,138

on use of mercury 204

Bowlder Creek, B. C, investigation on 13

stream conditions on 52

wood on, price of 215

Bowlders, handling of 141-142, 154

occurrence of ' 141

plate showing 68

Brackett, F. H., pipe-setting device of . . . 130, 132

Bridge over Klondike, view of 224

British Columbia, investigation in 13

roads in, comparison of American roads

and 16,219

views of 220, 224

Brooks, Alfred H., letter of transmittal by. 11

on Alaska roads 16, 219, 226

on legal abuses 256

Buck Creek, wood on, price of 216

Buckets, mining, plates showing. 66, 68, 160,168,178 Buster Creek, freight and passenger rates to_ 240

stream conditions on 53

California, comparison of conditions n

Alaska and 30,101

ditches in 113

dredging in 157-ln8

cost of 167-173

drifting in 83-84

hydraulic mining in 99-102

miner's inch in 50-51

rainfall in 47

sluices in, length of 144-145

tailings in 151

use of water gate in 57

Camp Colonna, rainfall at 48

temperatures at 49

Camp Davidson, rainfall at 48

temperatures at 49

Campbell, M. R., on gas-producer engines. 34,214

Candle Creek, gold on, fineness of 209

Candle district. See Fairhaven district.

Cantwell Creek, coal on 213

Carriers, self-dumping, cost and use of 65-67

Casadepaga River, freight and passenger

rates to 242

Chain, relative value of wire cable and 76-77

Chatham Creek, conditions on 32-33

freight and passenger rates to 238

gold on, fineness of 208

stream conditions on 53, 54

wood on, price of 216

Cheenik, freight and passenger rates to. 230-231,

Chena, freight and passenger rates to 235-236

Chicken Creek, gold on, fineness of 208

stream conditions on 54

wood on, price of 215

China pump, use of 56

use of, plate showing 56

Index.

Page.

Chisna district, gold on, fineness of 207

mining in, methods of 29

prospecting in, cost of II

wages in 21]

wood on, price of 212, 215

Chistochina district, freight and passenger

rates to 239

Chittitu Creek, gold on. fineness of 207

wood on, price of 215

Churn drill, plate showing 40

Circle, distances from 247

freight and passenger rates to and

from 233-235, 237-238

ice at 49

prices at 249-254

rainfall at 48

stream conditions at 49

temperatures at 49

Circle district, gold in, fineness of 208

stream conditions in 52, 54

wood on, price of 216

Circular letter, form of 17-25

sending of 14-15

Cleaning bed rock, cost of 59-60, 78

Cleary Creek, conditions on 32

ditches on 105, 109

freight and passenger rates to 238

gold on, fineness of ids

hot- water thawing on 98

prospecting in, cost of 41-42

road on, view of 226

stream conditions on 53, 54

wages on 211

wood on, price of 216

Climate, character of 30, 4g

effect of, on mining 29-30

on water supply 43-49

Coal, occurrence of 213-214

price of 34, 213-214

Collier, A. J., on Nome district 87

on tin 26

Colorado, miner's inch in 51

Controller Bay, coal at 213

Cooper Gulch, freight and passenger rates

to 240

Copper Center, rainfall at 48

temperatures at '. 49

Copper River, gold on, fineness of 207

wages in 211

wood on, price of 216

Cost of living, investigation into 15

Council, distances from 247

dredging buckets at, plate showing 168

freight and passenger rates to and

from 240, 242

Council City and Solomon River Railway,

construction of 228

Council district, ditches in 106,110

duty of miner's inch in 140

gold in, fineness of 209

hydraulic giants in 136

mining in, methods of 29

shoveling in, duty of man in 59

stream conditions in 53, 55

wages in 211

wood in, price of 216

Pi

ige

Cripple River, ditches on 106,109

freight and passenger rates to I'll

Crooked Creek, gold on, fineness of 209

investigation on 14

stream conditions on 5:;

wood on, price of 216

Crow Creek, ditches on 104,107

freight and passenger rates to 238

gold on, fineness of 207

wood on, price of 215

Crystophenes. See Ice, buried.

Customs, Tinted States, rates and regulations of 2 13-2 15

D.

Dagetkaket, freight and passenger rates to

and from 236-237

Daisy Creek, wood on, price of 216

Dams, construction of 56-58, 121,1 28

ci >st of 57, 150

plate showing 5s, 126, 1 18

Dams, protective, construction of 116,117

Dan Creek, gold on, fineness of 207

mining on, cost and methods of 37, 39

stream conditions on 54

wages on 211

wood on, price of 215

Davidson, J. W., acknowledgments to 25

on ditch building 123

Dawson, Y. T., freight and passenger rates

t o a i id from 233-235

prices at 249-254

rainfall at 48

source of supply at 243

temperatures at 49

Dawson carrier, description of 94-95

figure showing 94

Dawson district. See Klondike district,

Deadwood Creek, conditions on 32

ditches on 105, 109, 119

freight and passenger rates to 238

gold on, fineness of 208

investigation on 14

stream conditions on 52, 54

wages on 211

wood-fire thawing on 89-90

wood on, price of 216

Deering, freight and passenger rates to 240

Deri king, apparatus for, plates showing.. 66, To

plate showing 64

use and cost of 66-71

Dexter Creek, ditches on 10(5,109

freight and passenger rates to 240

gold on, fineness of 209

investigation on 14

stream conditions on 53,54

wood on, price of 21fi

Discovery Fork, shoveling on, duty of man

in 59

stream conditions on 52

wood on, price of 215

Distances, tables of 246-247

Ditches and Humes, construction of 103-126

construction of, diagrams and plates

showing 116, 120, 122, 126

cost of 119, 121, 123, 125-127

Index.

Page.

Ditches and flumes, data concerning 104-110

in Interior province 104, 117-120

in Juneau district, map showing 114

in Seward Peninsula 15,120-127

in South Coast province 113-117

views of 13,114,124,228

Domes, location and character of 31

Dominion Creek, gold on, fineness of 208

stream conditions on 52

Douglas Island, ditches on 104,107

ditches on, plate showing 114

Drains, construction and cost of 57-58

Dredges, buckets of, plates showing. . 160, 1G8, 178

parts of, figures showing 176, 179, 180, 182

types of 175-188

views of 160, 162, 168

Dredges, electric, use of 189

Dredging, advantages of 173, 189-190

conditions essential for 157-158

cost of 37-38, 159, 162-173

extension of 1 75

loss of time in 168, 188

obstacles to, in Alaska 158-159

operations of 160-167, 183-186

prospecting by 173-175

view of, plates showing 176, 184

Drift mining. See Mining, drift.

Drifting, cost of 40-41

prospecting by 41

prospecting rig for, figure showing 82

Drill, churn, plate showing 40

Drilling, prospecting by, cost and results of. 39-41,

Dry Creek, freight and passenger rates to.. 240

gold on, fineness of 209

investigation on 14

stream conditions on 53

wood on, price of 216

Dublikaket, freight and passenger rates to

and from 236-237

Dumping, method of, plates showing 62, 64

Dumping bucket, plates showing 40, 68

Dumps, plates showing 40, 192

sampling of, necessity for 42-43, 83

methods of 42-43

E.

Eagle, freight and passenger rates to 233-235

ice at 49

investigation at 14

rainfall at 43,48

stream conditions at 49

temperatures at 49

underground conditions at 158

Eagle Creek, drift mining on 87-88

freight and passenger rates to 238

gold on, fineness of 208

investigation on 14

prices on 88

stream conditions on 52, 54

wood on, price of 216

Eagle district, ditches in 105, 109

flume in, view of 228

gold in, fineness of 208

hydraulic mining in 117

map of 44

Page.

Eagle district, mining in, methods of 28

pipe lines in 119

stream conditions in 52, 54

wages in 211

wood on, price of 215

East Fork Creek, freight and passenger rates

to 242

Eldorado Creek, Y. T., ditches on 105,108

investigation on 14

steam shovel on 80-82

stream conditions on 52, 54

thawing on, plate showing 84

wood on, price of 215

Electric power, use of 33-34, 159

Elevators, hydraulic, cost of 152, 156

parts of, figures showing 153

principle of 151-152

types of 152-156

use of 155

views of 152, 154

-water needs of 154-155

Elluvial mining, definition of 26

Elmer, J. M., drift sheet devised by 163-164

Eureka Creek, stream conditions on 52

Evans, G. H., on hydraulic mining 112

on pipe lines 133

F.

Fairbanks, derricking at, plate showing... 64

distances from 247

freight and passenger rates to and from. 233-

235, 237-238

prices at 226-227, 249-254

source of supplies at 243

Fairbanks Creek, ditches on 105,109

drift mining on, plate showing 92

freight and passenger rates to 238

gold on, fineness of 194, 208

hot-water thawing on 98

investigation on 14

legal abuses on 256

stream conditions on 53-54

wages on 211

wood on, price of 216

Fairbanks district, ditches in 105, 109, 120

drain in, cost of 58

drifting in 96-99

garnets in 205

gold in, fineness of 208

ice in 89

investigation in 14

map of part of 46

mining in, cost and methods of 28, 36

physical conditions in 32-33, 96

prospecting in, cost of 41

rainfall in 45

road in, plate showing 220,226

shafts in, cost of 98

shoveling in, duty of man in 59

steam-point thawing in 91-92

stream conditions in 45, 53, 54

timbering in 98

topography in, view of 226

wages in 67,211

wood in. price of 216

Fairhaven district, coal in 213

Ikdkx.

Page.

Fairhaven district, gold in, fineness of 209

mining in, character of 29

prospecting in, cost of 42

wages in 211

wood in, price of 216

Firewood, prices of 34, 212-216

Flumes. See Ditches.

Fort Adams, rainfall at 48

temperatures at 49

Fort Gibbon, freight and passenger rates

to 233-235

ice at 49

rainfall at 48

temperatures at 49

Fort Liscum, rainfall at 48

temperatures at 49

Fort Reliance, ice at 49

Fort Yukon, freight and passenger rates

to 233-235

Fortymile, freight and passenger rates to. 233-234

Fortymile Creek, prospecting on, cost of . . . 41 stream conditions on 44

Fortymile district, ditches in 105, 109

hydraulic mining in 117

ice in 89

fineness of gold in 208

freight and passenger rates to 238

mining in, cost of 36

methods of 29

prospecting in, cost of 41

stream conditions in 44, 45, 54

wages in 211

wood in, price of 212, 215

Fountain Creek, freight and passenger

rates to 241

Freighting, cost of 88, 226, 228-242

investigation of 16

routes of 232-242

Frost, occurrence of 49

Fuel, prices of 34,88,102,212-216

G.

Galesburg, 111., steam-shovel operations at. 75-78 steam-shovel operations at, figures

showing 75, 76

Garnets, occurrence of 204

Gas-producer engines, efficiency of 34

use of 34

Geological Survey, United States, publications of, on Alaska 261-262

Geology, influence on placer mining of 31

Giants, hydraulic, bracing of, figure showing 136

data concerning 134-135

method of use of 136-137

Glacier Creek, ditch on, plate showing 124

ditches on 106, 109

elevators on 152 1 53

plate showing 152

freight and passenger rates to 241

gold on, fineness of 209

gravel on, plate showing 152

investigation on 14

sluicing on 149

stream conditions on 53, 54

wood on, price of 216

Page.

Glaeier Mountains, location and altitude

of 44

Glen Gulch, gold on, fineness of 208

stream conditions on 53

Gold, cleaning of 205

export duty on 215

fineness of 207 209

loss of 144-145, 191, 193

Gold, fine, occurrence of 193-194,207-209

Gold Bottom Creek (Council district)

ditches on 106, 110

freight and passenger rates to 242

investigation on 14

stream conditions on 53

Cold Bottom Creek, V. T., investigation on 14

Gold Creek, ditches on 104, 107

gold on, fineness of 207

stream conditions on 52, 54

topography on, plate showing 118

Gold deposits, alluvial, classes of 27

classes of, distribution of 28-29

methods of working of 27-28

Gold Run, B. C, dredging on 160-162

gold on, fineness of 207

investigation on 13

prospecting in, cost of 41

Gold Run (Kugruk district), gold on, fineness of 209

Gold Run (Rampart district), gold on, fineness of 208

stream conditions on... 53

wood on, price of 216

Gold Run, Y. T., gold on, fineness of 208

hot-water thawing on 93

investigation on 14

mud box on, view of 194

wood on, price of 215

stream conditions on 52, 54

Gold Run Creek, fineness of gold on 209

wood on, price of 215

Gold-saving devices, character of 142-150, 193

inefficiency of Alaskan types of 190

plates showing 80, 162

Gold Stream, stream conditions on 53

wood on, price of 216

Grades of streams. See Streams, grades of.

Grass Gulch, investigation on 14

Gravel, frozen, hydraulicking of, diagram

of 137

view of 136

Gravel mining, definition of 25-26

H.

Hannum Creek, gold on, fineness of 209

Hauer, J. D., on handling bowlders 141

Hidden Treasure mine, timbering method

in, figure showing 84

Hobson Creek, dam on 124

Hog River, freight and passenger rates to

and from 236-237

Hoisting, cost and methods of 94-96

Holyoke Creek, freight and passenger rates

to 240

Homestake Creek, gold on, fineness of 209

wood on, price of 216

Hoosier Creek, ditches on 105, 109

Index.

Page. Hoosier Creek, freight and passenger rates

to 237

stream conditions on 52

Hope, freight and passenger rates to and

from 230-231, 239

Horse scraping, cost and advantages of 61

Hospitals, fees for 210

Hot Air Co., flume of, plates showing 124, 126

Hot water, thawing by 33, 93-94, 97-98

Hunker Creek, Y. T., dam on 57

ditches on 105, 108, 118-119

gold on, fineness of 208

investigation on 14

steam-point thawing on 89-93

stream conditions on 52

wood on, price of 215

Hunter Creek, freight and passenger rates

to 237

gold on, fineness of 208

stream conditions on 52, 54

Hurrah Creek, freight and passenger rates

to 242

Hutchins, J. P., acknowledgments to 25

on dredging 173-190

on reservoirs 128

on thawing 137

Hydraulic mining. See Mining, hydraulic. Hydraulic pit, old timbering in, plate showing 86

Ice, occurrence of, time of 49

Ice, buried, occurrence of 119

Independence Creek, wood on, price of 216

Information, circular letter requesting 1 7-25

Inmachuk River, gold on, fineness of 209

wood on , price of 216

Interior province, districts in 28-29, 35

ditches in 104-105, 107-108

dredging in, cost of 167

fuel in, cost of 34

mining in, methods and cost of 28-29, 38

physical conditions in 30-33

roads in 219-226

topography of 117

plate showing 120

water supply of 36, 43-45

Investigation, itinerary of 13-14

methods of 14-25

Irene Gulch, gold on, fineness of 208

Itinerary, map showing

remarks on 13-14

J.

Jualpa Mining Company, ditch of 116

flume of, plate showing 118

Juneau, freight and passenger rates to... 230-231

investigation at 13

prices at 249-254

rainfall at 43, 48

temperatures at 49

Juneau district, ditches in 115-116

duty of miner's inch in 139

gold in, fineness of 207

map showing 114

Page.

Juneau district, mining in, methods of 28

prospecting in, cost of 41

roads in 221

stream conditions in 52, 54

wages in 211

wood on, price of 212, 215

K.

Kasson Creek, wood on, price of 216

Kelley, , method of sampling of 42-43

Kenai, rainfall at 48

stream conditions at

temperatures at 49

Kenai River, opening and closing of 49

stream conditions on 49

Kigluaik Mountains, location and altitude

of.. 46

Kiwalik, freight and passenger rates to. . 230-231 Klondike district, dam in, plate showing. 126, 148

ditches in 105, 108, 118

dredges and dredging in 162-164

plate showing 162

drift mining in 84-85

figure showing 85

dumping in, plate showing. . 62

dumps in, plate showing 40

duty of miner's inch in 139

frozen gravel in, view of 136

gold in, fineness of 207-208

hydraulic mining in 117

plate showing 86, 132, 136

ice in 89

investigation in 13

mining in, cost and methods of 28, 36

physical conditions in 32, 89

prices in 227

prospecting in, cost of 41

pumps in, plate showing 56

roads in 221

view of 224

si juices and si icing in 147-148

plate showing 136, 192, 194

steam shovel in 78-82

plate showing 74

steam- point thawing in 89, 93

stream conditions in 52, 54

wages in 67, 211

washing plant in, plate showing 80

white-channel deposits of 38, 118

wood in, price of 215

Klondike River, bridge over, view of 224

ditches on 106, 110

dredging on 160

steam shovel on 78-80

stream conditions on 52

Koksuktapaga River. See Casadepaga.

Kotzebue Sound, coal on 213

Kougarok district, mining in, character of. 29 Koyukuk district, freight and passenger

rates to 234

roads in 221

Koyukuk River, coal on 213

freight and passenger rates to and on. . 233-

234,236-237

Kugruk district, prospecting in, cost of 42

wages in 21 1

Index.

Page.

Kugruk River-, gold on, fineness of 209

wood on , price of 216

Labor, character and rates of pay of 210-211

Lnndfield. J. T., on gold dredging 157

Last Chance Creek, V. 'I'., freight and passenger rates to 241

gold on, fineness of 208

investigation on 14

Lawson Creek, ditch on, plate showing 114

Lemon Creek, ditches on 101,107

gold on, fineness of 207

Levat, E. P., on sluicing 197

on thawing in east Siberia 90

Lewington, G. A. R., acknowledgments to. 2.5

on ditch building 120

Lignite, occurrence of 213

Lillian Creek, freight and passenger rates

to 240

Lindbloom Creek, freight and passenger

rates to 241

Lindgren, W., on California rainfall 47

Lindley, C. H., on mining law 257-258, 260

Lisbnrne, Cape, coal near 213

Little Minook Creek, freight and passenger

rates to 237

gold on, fineness of 208

stream conditions on 52, 54

Little Minook, jr., Creek, gold on, fineness

of 208

Living, cost of, investigation into 15

Location, laws of 255-260

Long torn, character and use of 55-56

Lumber, character of 212

prices of 41-42, 88, 212-216

Lynx Creek, freight and passenger rates to. 239

M.

McCoon Creek, wood on, price of 215

McKee Creek, B. C, ditches on 104,107,118

gold on, fineness of 207

hydraulic giants on 136

investigation on 13

pipe line on 132

view of 132

prospecting on. cost of 41

sluicing on 143-144

stream conditions on 52, 54

tailings on 151

wood on, price of 21 5

McKinley Creek, gold on, fineness of 207

wood on, price of 215

McKinley Creek Mining Co. v. Alaska

United Mining Co., reference to. 260

Malum, H., on protective dams 146

Mammoth Creek, gold on, fineness of 208

investigation on 14

prospecting on, cost of 41

stream conditions on 52, 54

wood on, price of 216

Map of Alaska, showing itinerary 14

Martin Creek, freightand passenger rates to. 241

Page.

Mary's Igloo, distances from 247

Mastodon Creek, ditches on 105, 109

drain on, cost of 58

gold on, fineness of 208

investigation on h

prospecting on, cost of 41

self-dumping carriers on 65

stream conditions on 52, 54

tailings on 151

topography on. plate showing 120

wood on, price of 216

Mastodon Fork, gold on, fineness of 288

stream conditions on 52

Matanuska basin, coal in 213

Mattesoir, E. E., invention of hydraulic

mining by 99

Meking Creek, stream conditions on 53, 55

wood on, price of 216

Melting amalgam, method of 205-207

Mercury, use of 201

Miller Creek, Alaska, ditches on 104,107

gold on, fineness of 208

wood on, price of 216

Miller Creek, Y. T., ditches on 105, 108

Miller Gulch, gold on, fineness of 207

Mills Creek, freight and passenger rates to. 239

Miner, typical, plate showing 58

Miner's inch, definition of 34-35, 49-51

duty of 138-141

Mining, classes of, definitions of 25-26, 34-39

cost of, investigation of 15

Mining, alluvial, definition of 26

Mining, dredge. See Dredging. Mining, drift, adit for, plate and figure showing 84

cost of 38, 82-85

definition of 25

methods of 82-99

plate showing 92

rig for, figure showing 82

sampling in 83

system of, figure showing 83

Mining, elluvial, definition of 26

Mining, gravel, definition of 25-26

Mining, hydraulic, cost of 33,38,101-102

definition of 25

essentials for 100-101

invention of 99

methods of 99-156

plates and figures showing 92,

132,136,137,152,154

use of 33, 100, 102

water for 99

Mining, open-cut, cost of 38,56

economy of 55

methods of 55 82

steam point in, use of, plate showing .. 86

view Of 151

Mining, placer, definition of 25 26

methods of 29-34

conclusions concerning 30

Mining law, abuses of 255 jiin

extension of, to Alaska 257

requirements of 257-2*60

Mining supplies, prices of 249-254

Index.

Page.

Minook Creek, stream conditions on 52

Miocene Ditch Co., ditch of, map of 124

ditches of 123

view on 13, 124

Mission Creek, gold on, fineness of 208

Montana, miner's inch in 51

Montana dredge, type of 175-176

Moonlight Gulch, freight and passenger

rates to '240

More, A. H., acknowledgments to 25

Moss, effect of 88-89

Moss Gulch Creek, freight and passenger

rates to 240

Mud box, character and use of 191-192

cost of 193

plates and figure showing 192, 194

Munro, C. H., on cost of dredging 168-173

Mystery Creek, freight and passenger rates

to 242

gold on, fineness of 209

stream conditions on 53

N.

Neenana, freight and passenger rates to. . 235-236 New York, water supply of, theoretic capacity of, for hydraulic mining 99

New Zealand, dredge, type of 176-177

view of 162, 168, 167

Newton Creek, investigation on 14

Niukluk River, dredge on 167

Nizina district, gold in, fineness of 207

mining in, methods and cost of 29, 37-39

prospecting in, cost of 40

stream conditions on 54

wages in 211

wood on, price of 215

Nome, beach diggings at, gold at, fineness

of 209

distances from 247-248

freight and passenger rates to and

from 240-241

fuel at, cost of 34

gold at, fineness of 209

lightening at, cost of 239, 241

prices at 249-254

Nome Arctic Railway, construction of 227

Nome district, ditches in 105, 109

drift mining in 87, 93

duty of miner's inch in 138-140

gold in, fineness of 209

hot-water thawing in 97

hydraulic giants in 136

mining in, methods of 29

prospecting in, cost of 42

roads in 221

shoveling in, duty of man in 59

steam thawing in 93

stream conditions in 53, 54

wages in 211

wood in, price of 216

Nome River, ditches and ditch buildingon. 105,

ditches and ditch-building on, plate

showing 120

freight and passenger rates to 241

Page.

Nome River, stream conditions on 53

water supply of 46

Nugget Creek, freight and passenger rates

to 241

Nulato, freight and passenger rates to and

from 233-236

ice at 49

rainfall at 48

stream conditions at

temperatures at 49

O.

Oil, price of 34, 214

Omega Creek, freightand passenger rates to. 237

stream conditions on 53

Open-cut mining. See Mining, open-cut.

Ophir Creek, derricking on 67-70

plate showing 70

ditches on . 106,110,126-127

plate showing 126

flume on, view of 124

investigation on 14

mining on 37

freight and passenger rates to 240, 242

gold on, fineness of. 194,209

prospecting on, cost of 42

sluicing on 149

plate showing 148

stream conditions on £>3, 55

wageson 210

water supply of 46

wood on, price of 216

Oregon, use of water gate in 57

Oregon Creek, freight and passenger rates

to 241

Oroville, Cal., dredges and dredging at 157-

158, 176-177

dredges and dredging at, cost of 167-173

views of 168, 180, 182, 184

investigation at 14

Osborn Creek, freight and passenger rates

to 240

stream conditions on 53

Otter Creek, freight and passenger rates to. 241

P.

Pack train, view of 228

Paige, Sidney, acknowledgments to 13

work of 15

Pass, Siberian, view of 198

Passenger service, character of 228, 232

rates of 228-241

Peavy, freight and passenger rates to and

from 236-237

Pedro Creek, conditions in 32-33

derricking on, cost of 66-67, 70-71

freight and passenger rates to 238

gold on, fineness of 208

hot- water thawing on 98

prospecting on, cost of 42

stream conditions on 53,54

wood on, price of 216

Peluu Creek, freightand passenger rates to. 241

investigation on 14

wood on, price of 216

Penelope Creek, horse scraping on, cost of. . 60 investigation on 14

Index.

Page. Penny River, freight and passenger rates to . 24 1

Perkins, H. C, acknowledgments to 25

Pichard, G. W., on electric thawing 89

Pine Creek, B.C., ditches on 104,107

gold on, fineness of 207

investigation on 13

pipe line on, view of 128

stream conditions on 52, 54

wood on, price of 216

Pine Creek Power Co., sluices of 145

Pioneer Creek, ditches on 105, 109

freight and passenger rates to 241

stream conditions on 52

Pioneer Glen, freight and passenger rates to. 237

Pipe line, construction of 119, 128-134

construction of, figures and plate showing 132-133

prices of 130

sections and parts of, figures showing. . 129, 131,132,133

shipping of, method of 129

view of 128

Placer mining, character of 27

definition of 25-26

kinds of, distribution of 28-29

methods of working of 28

Placers, bench, character of 27

distribution of 28-29, 101

method of working of 28, 40, 101

Placers, creek, character of 27

distribution of 28-29

method of working of 27

Placers, gravel-plain, character of 27

distribution of 29

method of working of 28

Placers, hillside, character of 27

distribution of 28-29

method of working of 27

Placers, lake-bed, character of 27

distribution of 28

method of working of 28

Placers, river-bar, character of 27

distribution of 28-29

method of working of 28

richness of 159

Placers, sea-beach, character of 27

distribution of 29

method of working of 28

Placers, tundra. See Placers, gravel-plain.

Platinum, occurrence of 26

Porcupine Creek, wood on, price of 216

Porcupine district, ditches in 104, 108

freight and passenger rates to 238

gold in, fineness of 207

mining in, methods of 29

prospecting in, cost of 41

wages in 211

wood on, price of 212, 215

Port Clarence district, ditches in 106,110

gold in, fineness of 209

mining in, methods of 29

wages in 211

wood in, price of 216

Powers of attorney, abuse of 25.5-257

Pressure box, plates showing 116

Prindle, L. M., information from 61

Page.

Prindle, L. M., mention of II

Prospect Creek, freight and passenger rates

to 241

Prospecting, cost of 39, 41-42

methods of 39-40

results of 42-43

Pump, China. See China pump.

Pumping, cost of 58,102

Punched plates, use of 195-196

R.

Railways, construction of 227-228, 239

Rainfall, statistics of 48

Rampart, freight and passenger rates to and

from 233-234, 237

Rampart district, ditches in 105,109

gold in, fineness of 208

mining in, methods of 29

prospecting in, cost of 42

stream conditions in 45,52 -5 1

wages in 211

wood in, price of 215

Red Mountain, freight and passenger rates

to and from 236-237

Reservoirs, storage, construction and cost

of L27-128

Resurrection Creek, wood on, price of 216

Rhode Island Creek, freight and passenger

rates to 237

stream conditions on 53

Riffles, improved, figures and plates show

ing 80, 195, 200, 202,203

types of 200-203

Riffles, rail, figure showing 149

Roads, act of Congress concerning 217-218

construction and character of 16,

217-220,225-226

figure showing 225

cost Of 219, 220, 223-225, 227

in Interior province 226-227

in Seward Peninsula 227-228

in South Coast province 222

in Yukon Territory 222-226

suggested routes for 226

views of 220, 224, 226

Robinson, A. W., on dredging 160

Rock Creek, freight and passenger rates to. 241 stream conditions on 53

Rock Island Point, freight and passenger

rates to and from 236-237

Rocker, character and use of 55-56

figure showing 55

Ruby Creek, freight and passenger rates

to 237,242

stream conditions on 52

St. Michael, freight and passenger rates

to 230-231, 234-235

rainfall at 48

temperatures at 49

Sampling, necessity for 42 13,83

method of 42-43

Sand Point, freighl and passenger rates

to 230-231

Index.

Pa6e

Sawmills, location of 212-213

Seattle Creek, freight and passenger rates to. 240

stream conditions on 53

Seattle Point, freight and passenger rates to

and from 23G-237

Settling pond, view of 128

Seward, freight and passenger rates to. . . 230-231 Seward Peninsula, derricking in, plate

showing 70

distances in, table of 247

districts in 29, 35

ditches and ditch building in 15,

33, 46-47, 105-106, 109-110, 1 19-127

plates showing 120

dredging in 160, 164, 167

drifting in ... 87-88

gold in, fineness of 194

horse scraping in, cost of 60

machinery in, use of 121

magnetite in 205

map of part of 47

mining in, methods and cost of . . 29, 33, 36-38

moss in 88-89

physical conditions in 33-34, 88-89

roads in 219-221

settling pond in, view of 128-

sluicing in 149-150

wages in 82

water supply in 34-35, 45, 47

wood on 212

Shafts, prospecting, cost of 39-42

Shovel Creek, freight and passenger rates to. 242

stream conditions on 53, 55

Shoveling in, advantages of 59-60

cost of 37-38, 56, 59-60, 190

duty of a man in 59

Silver Bow basin, ditches in 104, 107, 1 15

flume in, view of lis

hydraulicking in, plate showing 92

investigation in 13

pressure box in, plate showing 116

sluicing in 143

Sixmile Creek, gold on, fineness of 207

Skagway, freight and passenger rates to . 230-231

rainfall at 48

temperatures at 49

Slate Creek, freight and passenger rate-i to. 237

gold on, fineness of 207

stream conditions on 52

wood on, price of 216

SledgeCreek, freightand passenger rates to. 211

Sluice, bed-rock, view of 136, 1 is

Sluice-box grade, definition of 54

Sluice boxes, cost of 197

character and use of 56-57

defects of 193-194

dumping into, plate showing 62

figures and plate showing . . . 143, 153, 196, 198,

grade of 195

making of, tools for, figure showing . . . 146

set-up of, plate showing 56

types of 195-199

use of, cost of 56, 190

Sluicing, cost of 39, 56, 57, 137, 142, 144, 148

efficiency of 141, 144-145

Page.

Sluicing, methods of 142-152

Smith, Hamilton, on miner's inch 50

pipe-line experiments by 134

Snake River, drilling on, plate showing ... 40

stream conditions on 53

Societe Miniere, plant of 146-147

Sod, use of 124, 128

Solomon, distances from 247

freight and passenger rates to and from . 230-

231,240,242

Solomon district, ditches in 106, 110

duty of miner's inch in 140

gold in , fineness of 209

mining in, methods of 29

stream conditions fn 53, 55

wages in 211

wood in, price of 216

Solomon Hill, drifting on, figure showing. . 85

Solomon River, dredging on 164, 166

gold on, fineness of 209

gravel on, tenor of 165

investigation on 14

shoveling on, duty of man in 59

stream conditions on 53, 55

water supply of 46

South Coast province, coal in 213

districts in 28-29, 35

ditches in 104, 107-108, 113-117

dredging in 160

gold of, character of 143

mining in, methods and cost of 28-29, 38

physical conditions in 30

roads in 219-222

topography of, plate showing 114

water supply of 43

wood in 214

Spruce Creek, B. C, ditches on 104, 107

gold on, fineness of 207

investigation on 13

prospecting in, cost of 41

stream conditions on 52

wood on, price of 215

Steam, use of 33, 37

Steam point, details of, figures showing 90

use of, in thawing 89-93, 96, 159, 189

plate and figure showing 90, 86

Steam scraper, advantages of 63-65

figures showing 61, 62, 65

use of 63-65

plate showing 62

Steam shovel, advantages of 73

cost of 77-78

operations of, description of 73-82

ligures showing 74,75,76

I dates showing 74

Stewart River, Y. T., dredging on 160

Stonehouse Fork, gold on, fineness of 208

Streams, freezing and opening of, time of. . 49

grades of 53-55

volumes of 49-53

Sulphur Creek, Y. T., fine gold on 201, 208

investigation on 14

stream conditions on 52

wood on, price of 215

Sunrise, freight and passenger rates to and

from. 230-231, 239

Index.

Page.

Sunrise district, ditches in 104,107

gold in, fineness of 207

mining in, methods of 29

prospecting in, cost of 11

wages in 211

wood on, price of 212, 215

Sunset Creek, ditches on 106, 110

gold on, fineness of 209

T.

Tal>les, gold-saving, view of 162

Tailings, disposal of 150-151, 183-186

disposal of, figures showing 183, 185, 187

Tanana, freight and passenger rates to .. 235-23(5

ice at I'.t

Tanana district, gold in, character of 194

hydraulic mining in 1 17

roads in 221

wood on, price of 212

Tanana River, freight and passenger rates

to and on 234, 235-236

gold fields on, information concerning. 14

Telegraph charges, rates of 244-245

Teller, distances from 247

freight and passenger rates to and

from 230-231, 240

Temperature, records of 49

Thanksgiving Creek, freight and passenger

rates to 237

gold on, fineness of 20

stream conditions on 53

Thawing, cost of 41-42, 189

methods of 33, 40, 89, 137

necessity for 40, 88

plate showing 84

Thibaudeau, W. , information from 222

Timber supplies, investigation of 15

Timbering, cost of 41-42, 88, 212-216

method of, figure showing 84

remains of, plate showing 86

Tin, occurrence of 26

Tolmachof, I. P., on buried ice 119

Tolovana, freight and passenger rates to. 235-236

Topkok district, mining in, methods of 29

Topography, influence on mining of '31

mention of 16

views showing 114, 118, 120, 226

Track and incline system, advantages of . . 72

figure showing 71

use of 71-72

Tramming system, cost of 37, 73

description of 75-76

view of 154

Transportation, cost of, investigation of ... 16

Trommel, use of 19J

use of, plate showing 162

Twin Creek, conditions on 32

gold on, fineness of 208

Twin Mountain Creek, freight and passenger rates to 241

Tyrrell, J. B., on buried ice 119

U.

Undercurrent, figures showing I'.t l, L96

use of, in sluicing 196-197

Page.

Upper Dominion Creek, V. 'I'., investiga

lion on 14

steam-point thawing on 89

1 on. price of 215

Valdez, freight and passenger rates to ... 230 231 Van Waagenen,T. F., on hydraulic mining. Ill

W.

Wade Creek, ditches on 105, 109

gold on, fineness of 208

stream conditions on 51

W 1 on, price of 215

Wages, investigation into 15

rates of 33,82 83,210 211

Walker Fork, gold on, fineness of 208

steam scraper on, use of t'.l 62

use of, plate showing 62

stream conditions on 51

wood on, price of 215

Warm Creek, investigation on 14

stream conditions on 53

Washing plant, necessity for 37, 7:'.. I'.t:;

plate showing 80

Washington Creek, freight and passenger

rates to 240

Water, underground, difficulty from 40

Water gate, use and cost of 38, 57

Water supply, data concerning 4;>-55

investigation into 15

West, William, acknowledgments to 25

West Creek, freight and passenger rates to. 242 Whitney, J. D., on hydraulic mining.. 99-100,102

Wild Goose Railway, construction of 227-228

Willow Creek, B. C, freight and passenger

rates to 211,212

gold on, fineness of 207

investigation on 13

Windfall Creek, ditches on 104, 107

gold on, fineness of 207

wood on, price of 215

Wire cables, relative value of chains and .. 76-77

Wolf Creek, stream conditions on 53

Wood, prices of 34, 212-216

Wood fires, thawing by 89-90

Woodchopper Creek, gold on. fineness of. . . 208

wood on, price of 216

Wrangell, freight and passenger rates t,,. 230-231

Yakutat, freight and passenger rates to.. 230-231

York, freight and passenger rates to 210

York Mountains, location of 46

water of 46

Young, H.W.,on gold-saving devices — 1.95,203

Yukon River, coal at 213

freight and passenger rates to 234

opening and closing of 19

stream conditionson 49

Yukon Territory, Canada, investigation in. 13 1 1

miner's inch in 51

roads in 222 226

views of 224

Bull. 263—05-

o

Publications Of United States Geological Survey.

[Bulletin No. 263.]

The serial publications of the United States Geological Survey consist of (1) Annual Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) . Mineral Resources, (6) Water-Supply and Irrigation Papers, (7) Topographic Atlas of United States — folios and separate sheets thereof, (8) Geologic Atlas of the United States — folios thereof. The classes numbered 2, 7, and 8 are sold at cost, of publication; the others are distributed free. A circular giving complete lists may be had on application.

Mostof the above publications may be obtained or consulted in the following ways:

1. A limited number are delivered to the Director of the Survey, from whom they may be obtained, free of charge (except classes 2, 7, and 8), on application.

2. Every member of Congress is allotted a certain number, from whom they may be obtained, free of charge, on application.

3. Other copies are deposited with the Superintendent of Documents, Washington, D. C, from whom they may be had at practically cost.

4. Copies of all Government publications are furnished to the principal public libraries in the large cities throughout the United States, where they may be consulted by those interested.

The Professional Papers, Bulletins, and Water-Supply Papers treat of a variety of subjects, and the total number issued is large. They have therefore been classified in the following series: A, Economic geology; B, Descriptive geology; C, Systematic geology and paleontology; D, Petrography and mineralogy; E, Chemistry and physics; F, Geography; G, Miscellaneous; H, Forestry; I, Irrigation; J, Water storage; K, Pumping water; L, Quality of water; M, General hydrographic investigations; N, Water power; O, Underground waters; P, Hydrographic progress reports. This bulletin is the fifty-fifth in Series A, the complete list of which follows. (PP=Professional Paper; B Bulletin; WS Water-Supply Paper.)

Series A, Economic Geology.

B 21. Lignites of Great Sioux Reservation: Report on region between Grand and Moreau rivers,

Dakota, by Bailey Willis. 1885. 16 pp., 5 pis. (Out of stock.) B 46. Nature and origin of deposits of phosphate of lime, by R. A. F. Penrose, jr., with introduction

by N. S. Shaler. 1888. 143 pp. (Out of stock.) B 65. Stratigraphy of the bituminous coal field of Pennsylvania, Ohio, and West Virginia, by I.

White. 1891. 212 pp., 11 pis. (Out of stock.) B 111. Geology of Big Stone Gap coal field of Virginia and Kentucky, by M. R. Campbell. 1893. 106

pp., 6 pis. B 132. The disseminated lead ores of southeastern Missouri, by Arthur Winslow. 1896. 31 pp. B 138. Artesian-well prospects in Atlantic Coastal Plain region, by N. H. Darton. 1896. 228 pp., 19

pis. (Out of stock.) B 139. Geology of Castle Mountain mining district, Montana, by W. II. Weed and L. V. Pirsson. 1896.

164 pp., 17 pis. B 143. Bibliography of clays and the ceramic arts, by J. C. Branner. 1896. 1 1 1 pp. B 161. Reconnaissance on the Rio Grande coal fields of 1'exas, by T. W. Vaughan, including a report

on igneous rocks from the San Carlos coal field, by E. C. E. Lord. L900. 100 pp., 11 pis. B 178. El Paso tin deposits, by W. H. Weed. 1901. 15 pp., 1 pi.

B 180. Occurrence and distribution of corundum in United States, by J. II. Pratt. 1901. 98 pp., 14 pis. B 182. A report on the economic geology of the Silverton quadrangle, Colorado, by F. I.. Ransome.

1901. 266 pp., 16 pis.

B 184. Oil and gas fields of ,the western interior and northern Texas Coal Measures and of the Upper Cretaceous and Tertiary of the western Gulf coast, by G. I. Adams. L901. 64 pp., 10 pis. (Out of stock.)

B 193. The geological relations and distribution of platinum and associated metals, by . I. F. Kemp

1902. 95 pp., 6 pis. (Out of stock.)

B 198. The Berea grit oil sand in the Cadiz quadrangle, Ohio, by W. T. Oris wold. 1902. 43 1 pi. PP1. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska, by Alfred Hulse Brooks. 1902. 120 pp., 2 pis.

Ii Advertisement.

B 200. Reconnaissance of the borax deposits of Death Valley and Mohave Desert, by M. R. Campbell.

1902. 23 pp., 1 pi. B 202. Tests for gold and silver in shales from western Kansas, by Waldemar Lindgren. 1902. 21 pp. PP 2. Reconnaissance of the northwestern portion of Seward Peninsula, Alaska, by A. J. Collier.

1902. 70 pp., 11 pis. PP 10. Reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dall, Kanuti, Allen,

and Kowak rivers, by W. C. Mendenhall. 1902. 68 pp., 10 pis. PP 11. Clays of the United States east of the Mississippi River, by Heinrich Ries. 1903. 298 pp., 9 pis. PP 12. Geology of the Globe copper district, Arizona, by F. L. Ransome. 1903. 168 pp., 27 pis. B 212. Oil fields of the Texas-Louisiana Gulf Coastal Plain, by C. W. Hayes and William Kennedy.

1903. 174 pp., 11 pis. B 213. Contributions to economic geology, 1902; S. F. Emmons, C. W. Hayes, geologists in charge.

1903. 449 pp.

PP 15. The mineral resources of the Mount Wrangell district, Alaska, by W. C. Mendenhall and

F. C. Schrader. 1903. 71 pp., 10 pis. B 218. Coal resources of the Yukon, Alaska, by A. J. Collier. 1903. 71 pp., 6 pis. B 219. The ore deposits of Tonopah, Nevada (preliminary report), by J. E. Spurr. 1903. 31 pp., 1 pi. PP 20. A reconnaissance in northern Alaska, in 1901, by F. C. Schrader. 1904. 139 pp., 16 pis. PP 21. Geology and ore deposits of the Bisbee quadrangle, Arizona, by F. L. Ransome. 1904. 168 pp.,

29 pis. B 223. Gypsum deposits of the United States, by G. I. Adams and others. 1904. 129 pp., 21 pis. PP 24. Zinc and lead deposits of northern Arkansas, by G. I. Adams. 1904. 118 pp., 27 pis. PP 25. Copper deposits of the Encampment district, Wyoming, by A. C. Spencer. 1904. 107 pp., 2 pis. B 225. Contributions to economic geology, 1903; S. F. Emmons, C. W. Hayes, geologists in charge.

1904. 527 pp., 1 pi.

PP 26. Economic resources of the northern Black Hills, by J. D. Irving, with contributions by S. F. Emmons and T. A. Jaggar, jr. 1904. 222 pp., 20 pis.

PP 27. A geological reconnaissance across the Bitterroot Range and Clearwater Mountains in Montana and Idaho, by Waldemar Lindgren. 1904. 123 pp., 15 pis.

B 229. Tin deposits of the York region, Alaska, by A. J. Collier. 1904. 61 pp., 7 pis.

B 236. The Porcupine placer district, Alaska, by C. W. Wright. 1904. 35 pp., 10 pis.

B 238. Economic geology of the Iola quadrangle, Kansas, by G. I. Adams, Erasmus Haworth, and W. R. Crane. 1904. 83 pp., 11 pis.

B 243. Cement materials and industry of the United States, by E. C. Eckel. 1905. 395 pp., 15 pis.

B 246. Zinc and lead deposits of northwestern Illinois, by H. Foster Bain. 1904. 56 pp., 5 pis.

B 247. The Fairhaven gold placers, Seward Peninsula, Alaska, by F. H. Moffit. 1905. 85 pp., 14 pis.

B 249. Limestones of southeastern Pennsylvania, by F. G. Clapp. 1905. 52 pp., 7 pis.

B 250. The petroleum fields of the Pacific coast of Alaska, with an account of the Bering River coal deposits, by G. C. Martin. 1905. 64 pp., 7 pis.

B 251. The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska, by L. M. Prindle.

1905. 89 pp., 16 pis.

WS 117. The lignite of North Dakota and its relation to irrigation, by F. A. Wilder. 1905. 59 pp., 8 pis. . PP 36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. O. Ulrich and W. S. T. Smith.

1905. 218 pp., 15 pis. PP 38. Economic geology of the Bingham mining district of Utah, by J. M. Boutwell, with a chapter

on areal geology, by Arthur Keith, and an introduction on general geology, by S. F. Emmons.

1905. 413 pp., 49 pis. PP41 Thegeology olthecentral Copper River region, Alaska, by W.C. Mendenhall. 1905. — pp., — pis. B 254. Report of progress in the geological resurvey of the Cripple Creek district, Colorado, by Waldemar Lindgren and F. L. Ransome. 1904. 36 pp. B 255. The fluorspar deposits of southern Illinois, by H. Foster Bain. 1905. 75 pp., 6 pis. B 256. Mineral resources of the Elders Ridge quadrangle, Pennsylvania, by R. W. Stone. 1905.

— pp., 12 pis. B 259. Report on progress of investigations of mineral resources of Alaska, in 1904, by A. H. Brooks

and others. 1905. 196 pp., 3 pis. B 260. Contributions to economic geology, 1904; S. F. Emmons, C. W. Hayes, geologists in charge.

1905. 620 pp., 4 pis. B 261. Preliminary report on the operations of the coal-testing plant of the United States Geological

Survey at the Louisiana Purchase Exposition, St. Louis, Mo., 1904; E. W. Parker, J. A. Holmes,

M. R.Campbell, committee in charge. 1905. 172 pp. B263. Methods and costs of gravel andplacerminingin Alaska, byC. W. Purington. 1905. 273pp., 42pls.

Correspondence should be addressed to

The Director,

United States Geological Survey,

Washington, D. C. June, 1905.

Geological Survey Publications On Alaska.

Russell, I. C. Account of an expedition to the Yukon Valley in 1889. In Eleventh Ann. Rept., pt. 1, 1891, pp. 57-58. Extract from Professor Russell's complete report in Bull. Geol. Soc. America, vol. 1, 1890, pp. 99-162. (Out of stock. )

Account of an expedition to the vicinity of Mount St. Elias in 1890. In

Twelfth Ann. Rept., pt. 1, 1891, pp. 59-61. A full report of this expedition was published in Nat. Geog. Mag., vol. 3, 1892, pp. 53-203. (Out of stock. )

Dall, W. H., and Harris, G. D. Summary of knowledge of Neocene geology of Alaska. In correlation Papers— Neocene: Bull. No. 84, 1892, pp. 232-268.

Hayes, C. W. Account of expedition through the Yukon district. In Thirteenth Ann. Rept., pt. 1, 1892, pp. 91-94. A complete report was published in Nat. Geog. Mag., vol. 4, 1892, pp. 117-162. (Out of stock.)

Russell, I. C. Second expedition to Mount St. Elias in 1891. Rept., pt. 2, 1893, pp. 1-91. (Out of stock.)

In Thirteenth Ann.

Ball, W. H. Report on coal and lignite of Alaska In Seventeenth Ann. Rept.,

pt. 1, 1896, pp. 763-906. (Out of stock.) Reid, H. F. Glacier Bay and its glaciers. In Sixteenth Ann. Rept., pt, 1, 1896,

pp. 415-461. (Out of stock.) Walcott, C. D. , Director. Account of an investigation of the gold and coal deposits

of southern Alaska. In Seventeenth Ann. Rept., pt. 1, 1896, pp. 56-59.

(Out of stock.)

Walcott, C. D., Director. Account of a reconnaissance of the gold district of the Yukon region. In Eighteenth Ann. Rept., pt. 1, 1897, pp. 52-54. (Out of stock. )

Bkckek, G. E. Reconnaissance of the gold fields of southern Alaska, with some notes on general geology. In Eighteenth Ann. Rept., pt. 3, 1898, pp. 1-86. (Out of stock. )

Spurk, J. E., and GooDRicn, H. B. Geology of the Yukon gold district, Alaska, by Josiah Edward Spurr; with an introductory chapter on the history and condition of the district to 1897, by Harold Beach Goodrich. In Eighteenth Ann. Rept., pt. 3, 1898, pp. 87-392. (Out of stock.)

Walcott, C. D., Director. Account of operations in Alaska in 1898. In Nineteenth Ann. Rept., pt. 2, 1898, pp. 20, 53, 116-117.

Map of Alaska, showing known gold-bearing rocks, with descriptive text containing sketches of the geography, geology, and gold deposits and routes to the gold fields. Prepared in accordance with Public Resolution No. 3 of the Fifty-fifth Congress, second session, approved January 20, 1898. Printed in the engraving and printing division of the United States Geological Survey, Washington, D. C, 1898. 44 pp., 1 map. A special publication. The data were brought together by S. F. Emmons, aided by VY. H. Dall and F. C. Schrader. (Out of stock. )

Iv Advertisement.

Walcott, C. D., Director. Account of operations in Alaska in 1899. In Twentieth Ann. Kept. U. S. Geol. Survey, pt. 1, 1899, pp. 12, 52-53, 97, 126-134. (Out of stock.)

Maps and descriptions of routes of exploration in Alaska in 1898, with general information concerning the Territory. (Ten maps in accompanying envelope. ) Prepared in accordance with Public Resolution No. 25 of the Fifty-fifth Congress, third session, approved March 1, 1899. Printed in the engraving and printing division of the United States Geological Survey, Washington, D. C, 1899. 138 pp., 10 maps in accompanying envelope. A special publication. Contributors: G. H. Eldridge, Robert Muldrow, J. E. Spurr, W. S. Post, W. C. Mendenhall, F. C. Schrader, W. J. Peters, A. H. Brooks, and E. C. Barnard. (Out of stock.)

Baker, Marcus. Alaskan geographic names. In Twenty-first Ann. Rept., pt. 2, 1900, pp. 487-509.

Brooks, A. H. A reconnaissance from Pyramid Harbor to Eagle City, Alaska, including a description of the copper deposits of the upper White and Tanana rivers. In Twenty-first Ann. Rept., pt. 2, 1900, pp. 331-391.

A reconnaissance in the Tanana and White River basins, Alaska, in 1898.

In Twentieth Ann. Rept., pt. 7, 1900, pp. 425-494. (Out of stock.) Eldridge, G. H. A reconnaissance in the Sushitna basin and adjacent territory,

Alaska, in 1898. In Twentieth Ann. Rept, pt. 7, 1900, pp. 1-29. (Out

of stock. ) Gannett, Henry. Altitudes in Alaska. Bull. No. 169, 1900, 13 pp. Mendenhall, W. C. A reconnaissance from Resurrection Bay to the Tanana River,

Alaska, in 1898. In Twentieth Ann. Rept., pt. 7, 1900, pp. 265-340.

(Out of stock.) Rohn, Oscar. A reconnaissance of the Chitina River and the Skolai Mountains,

Alaska. In Twenty-first Ann. Rept., pt. 2, 1900, pp. 303-340. (Out of

stock. ) Schrader, F. C. A reconnaissance of a part of Prince William Sound and the Copper River district, Alaska, in 1898. In Twentieth Ann. Rept., pt. 7, 1900,

pp. 341-423. (Out of stock.)

Preliminary report on a reconnaissance along the Chandlar and Koyukuk

rivers, Alaska, in 1899. In Twentv-first Ann. Rept., pt. 2, 1900, pp. 441-

and Brooks, A. H. Preliminary report on the Cape Nome gold region,

Alaska, with maps and illustrations. Washington, Government Printing Office, 1900. 56 pp. 3 maps and 19 pis. A special publication.

Spurr, J. E. A reconnaissance in southwestern Alaska in 1898. In Twentieth Ann. Rept,, pt, 7, 1900, pp. 31-264.

Walcott, C. I)., Director. Account of operations in Alaska in 1900. In Twentyfirst Ann. Rept., pt, 1, 1900, pp. 17-18, 86, 145-149.

Brooks, A. H. An. occurrence of stream tin in the York region, Alaska. In Mineral Resources of the U. S. for 1900, 1901, pp. 267-271. Published also as a separate, Washington, Government Printing Office, 1901, cover and pp. 1-5. (Out of stock.)

The coal resources of Alaska. In Twentv-second Ann. Rept., pt. 3, 1901,

pp. 515-571.

, Richardson, G. B., and Collier, A. J. A reconnaissance of the Cape Nome

and adjacent gold fields of Seward Peninsula, Alaska, in 1900. In a special publication entitled " Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in 1900," Washington, Government Printing Office, 1901, pp. 1-180.

Mendenhall, W. C. A reconnaissance in the Norton Bay region, Alaska, in 1900. In a special publication entitled "Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in 1900," Washington, Government Printing Office, 1901, pp. 181-218.

Schrader, F. C, and Spencer, A. C. The geology and mineral resources of a portion of the Copper River district, Alaska. A special publication, Washington, Government Printing Office, 1901, pp. 1-94.

Walcott, C. D., Director. Account of operations in Alaska in 1901. In Twentysecond Ann. Rept., pt. 1, 1901, pp. 35, 95-99, 144, 166-170.

Advertisement.

Brooks, A. II. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of the geology of southeastern Alaska. Professional Paper No. 1, 1902, pp. 1-120.

Collier, A. J. A reconnaissance of the northwestern portion of Seward Peninsula, Alaska. Professional Paper No. 2, 1902, pp. 1-70.

Mendenhall, W. C. A reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dall, Kanuti, Allen, and Kowak rivers. Professional Paper No. 10, 1902, pp. 1-68.

Walcott, C. I)., Director. Account of operations in Alaska in 1902. In Twentythird Ann. Rept., 1902, pp. 20, 21,57, 71-82, 161.

Baker, Marcus. Geographic dictionary of Alaska. Bull. No. 187, 1902, pp. 1-446. Brooks, A. II. Placer gold mining in Alaska in 1902. In Bull. No. 213, 1903, pp. 41-48. (Out of stock.)

Stream tin in Alaska. Jn Bull. No. 213, 1903, pp. 92-93. (Out of stock.)

Collier, A. J. Coal resources of the Yukon basin, Alaska. In Bull. No. 213, 1903,

pp. 276-283. ( Out of stock. )

The coal resources of the Yukon, Alaska. Bull. No. 218, 1903, pp. 1-71.

The Glenn Creek gold mining district, Alaska. In Bull. No. 213, 1903, pp.

49-56. (Out of stock.) Mendenhall, W. C. The Chistochina gold field, Alaska. In Bull. No. 213, 1903,

pp. 71-75. (Out of stock.) and Schrader, F. C. Copper deposits of Mount Wrangell region, Alaska.

In Bull. No. 213, 1903, pp. 141-148. (Out of stock.)

The mineral resources of the Mount Wrangell district, Alaska. Professional

Paper No. 15, 1903, pp. 1-71. Walcott, C. D., Director. Account of operations in Alaska in 1903. In Twentvfourth Ann. Rept, 1903, pp. 78-107, 167, 256.

Brooks, A. H. Placer gold mining in Alaska in 1903. In Bull. No. 225, 1904, pp.

Collier, A. J. Tin deposits of the York region, Alaska. In Bull. No. 225, 1904,

pp. 154-167.

Tin deposits of the York region, Alaska. Bull. No. 229.

Martin, G. C. Petroleum fields of Alaska and the Bering River coal field. In Bull.

No. 225, 1904, pp. 365-382. Moffit, F. H. The Kotzebue placer gold field of Seward Peninsula, Alaska. In

Bull. No. 225, 1904, pp. 74-80. Prindle, L. M. Gold placers of the Fairbanks district, Alaska. In Bull. No. 225,

1904, pp. 64-73. Schrader, F. G, and Peters, W. J. A reconnaissance in northern Alaska, across

the Rocky Mountains, along the Koyukuk, John, Anaktuvuk, and Col-

ville rivers, and the Arctic coast to Cape Lisburne, in 1901. Professional

Paper No. 20, 1904, pp. 1-139. Spencer, A. C. The Juneau gold belt, Alaska. In Bull. No. 225, 1904, pp. 28-42. Walcott, C. D., Director. Account of operations in Alaska in 1904. In Twenty-fifth

Ann. Rept., 1904, pp. 68-85, 346, 348, 352, 354. Wright, C. W. The Porcupine placer mining district, Alaska. In Bull. No. 225,

1904, pp. 60-63.

The Porcupine placer district, Alaska. Bull. No. 236, 1904, pp. 1-35.

Brooks, Alfred H. The geography and geology of Alaska. A summary of existing knowledge, with a chapter on climate by Cleveland Abbe, jr., and a topographic map and description thereof by R. U. Goode. Professional Paper No. — .

and others. Progress report for 1904 of division of Alaskan Mineral Resources.

Bull. No. 259, 1905, pp. 1-190.

Martin, G. C. The petroleum fields of the Pacific coast of Alaska and the Bering River coal field. Bull. No. 250, 1905, pp. 1-65.

Mendenhall, W. C. The geology of the central Copper River region, Alaska. Professional Paper No. 4 1 .

Vi Advertisement.

Moffit, F. H. The Fairhaven gold placers, Seward Peninsula, Alaska. Bull. No. 247,

1905, pp. 1-85. Prindle, L. M. The gold placers of the Fortymile, Birch Creek, and Fairbanks

regions. Bull. No. 251, 1905, pp. 1-89. Purington, C. W. Methods and cost of gravel and placer mining in Alaska. Bull.

No. 263, 1905, pp. 1-273.

Papers On Alaska In Preparation.

Brooks, A. H. An exploration in the Mount McKinley region. Collier, Arthur J. Placer mines of Seward Peninsula.

Coal field of Cape Lisburne.

Martin, G. C. The geology of Alaska Peninsula.

Moffit, F. H. The Cook Inlet gold placers.

Prindle, L. M., and Hess,"F. L. The gold placers of the Rampart region.

Schrader, F. C. The geology of upper Copper and Tanana rivers.

Stone, R. W. The Kachemak Bay coal fields.

Spencer, Arthur C. The Juneau gold belt.

Wright, C. W. The mineral resources of Admiralty Island.

Wright, F. E. The mineral resources of the Wrangell district.

The mineral resources of the Sitka district.

Topographic Maps Of Alaska.

The following maps are on sale at 5 cents a copy, or $2 a hundred:

Barnard, E. C. Fortymile quandrangle; scale, 1:250000. Peters, W. J. Juneau special quadrangle; scale, 1:63500.

The following maps are included as illustrations of published reports, but have not been issued separately. They can be obtained only by securing the report:

Barnard, E. C. Cape Nome and adjacent gold fields; scale, 1 : 250000. Contained in a special publication of the U. S. Geol. Survey, entitled "Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in 1900," Washington, Government Printing Office, 1901.

Brooks, A. H. York and Kugruk regions, sketch maps of. Contained in "A reconnaissance in Cape Nome and Norton Bay regions, Alaska, 1900."

Gerdine, T. G. Koyukuk and Chandlar rivers, portions of; scale, 1 : 625000. Contained in "Preliminary report of a reconnaissance along the Chandlar and Koyukuk rivers, Alaska, in 1899." Twenty-first Ann. Rept., pt. 2, 1900.

Seward Peninsula, northwestern part of ; scale, 1 : 250000. Contained in Pro-

fessional Paper No. 2.

Fairbanks and Birch Creek districts, reconnaissance maps of; scale, 1 : 250000.

Contained in "The gold placers of Fortymile, Birch Creek, and Fairbanks districts." Bulletin No. 251.

Yukon-Tanana region, reconnaissance map of; scale, 1:625000.

Copper and upper Chistochina rivers; scale, 1:250000. Contained in "A

geology of the central Copper River basin." Professional Paper No. 41.

and Witherspoon, D. C. Chitina and lower Copper River region; scale,

1:250000. Contained in "The geology and mineral resources of a portion of the Copper River district, Alaska." Special Publication of the U. S. Geol. Survey, Washington, Government Printing Office, 1901.

Goode, R. U. A topographic map of Alaska; scale, 1: 250000. Preliminary edition. Contained in Professional Paper No. — .

Lowe, P. G., Mahlo, Emil, and Schrader, F. C. Copper River region; scale, 1:376000. Contained in "A reconnaissance of a part of Prince William Sound and the Copper River district, Alaska, in 1898." Twentieth Ann. Rept,, pt, 7, 1900, pp. 341-423. (Out of stock.)

Mahlo, Emil, and Schrader, F. C. Prince William Sound, sketch map of; scale 1:376000. Contained in "The geology and mineral resources of a portion of the Copper River district, Alaska." (Out of stock.)

Mendenhall, W. C. Cook Inlet, head of, to the Tanana via Matanuska and Delta rivers, also part of Kenai Peninsula; scale, 1:625000. Contained in "A reconnaissance from Resurrection Bav to Tanana River, Alaska, in 1898." Twentieth Ann. Rept., pt. 7, pp. 265-340.

Muldrow, Robert. Sushitna River and adjacent territory; scale, 1:625000. Contained in "A reconnaissance in the Sushitna basin and adjacent territory, Alaska, in 1898." Twentieth Ann. Rept., pt. 7, 1900, pp. 1-29.

Advertisement. Vii

Peters, W. J. Tanana and White rivers, portions of; scale, 1:625000. Contained in "A reconnaissance in the Tanana and White River basins, Alaska, in 1898." Twentieth Ann. Kept,, pt. 7, 1900, pp. 425-494.

Lynn canal, routes from, via headwaters of White and Tanana rivers to

Eagle City; scale, 1:625000. Contained in "A reconnaissance from Pyramid Harbor to Eagle Citv, Alaska." Twenty-firsl Ann. Kept., pt. 2, L900, pp. 331-391.

Norton Bay region; scale, 1 : 625000. Contained in "Reconnaissances of

Cape Nome and Norton Bay regions, Alaska," 1900.

Koyukuk River to month of Colville River, including John River; scale,

1: 625000. Included in Professional Paper No. 20.

Post, W. S. Cook Inlet, region from head of, to Kuskokwim River and down the Kuskokwim to Bering Sea, Bristol Bay, and a part of Alaska Peninsula; scale, 1:625000. Published in sections in "A reconnaissance in Southwestern Alaska, in 1898." Twentieth Ann. Rept, pt. 7, 1900, pp. 31-264.

Reaburn, D. L. The Mount McKinley region; scale, 1:250000. Contained in Professional Paper No. — .

Witherspoon, D. C. Copper, Nabesna, and Chisana rivers, headwaters of; scale, 1 : 250000. Contained in " The geology of the central Copper River region. ' ' Professional Paper No. 41.

Seward Peninsula, northeastern portion of, topographic reconnaissance of;

scale, 1:250000. Contained in "The Fairhaven gold placers, Seward Peninsula." Bull. No. 247.

Topographic Maps Of Alaska In Preparation.

Witherspoon, D. C. The Fairbanks placer district; scale, 1 : 250000. Gerdine, T. G. The Nome district; scale, 1 : 62500. Hamilton, E. G. The Cook Inlet placer fields; scale, 1 : 250000.

Library Catalogue Slips.

[Mount each slip upon a separate card, placing the subject at the top of the second slip. The name of the series should not be repeated on the series card, but the additional numbers should be added, as received, to the first entry.]

Purington, Chester Wells, 1871-

. . . Methods and costs of gravel and placer mining in Alaska, by Chester Wells Purington. Washington Gov't print, off., 1905.

273, ix p. illus., XLII pi. (inch map) diagrs. 23J cm survey. Bulletin no. 263)

Subject series: A, Economic geology, 55.

" Notes on dredging, by J. P. Hutchins;" p. 173-190.

Bibliography; p. 261-262.

1. Gold mines and mining — Alaska.

( U. S. Geological

Purington, Chester Wells, 1871-

... Methods and costs of gravel and placer mining f in Alaska, by Chester Wells Purington. Washington, Gov't print, off., 1905.

273, ix p. illus., XLII pi. (inch map) diagrs. 23|cm. (U. S. Geological survey. Bulletin no. 263)

Subject series: A, Economic geology, 55.

" Notes on dredging, by J. P. Hutchins;" p. 173-190.

Bibliography; p. 261-262.

1. Gold mines and mining — Alaska.

U. S. Geological survey.

Bulletins.

j no. 263. Purington, C. W. Methods and costs of gravel and placer mining in Alaska. 1905.

c U.S. Dept. of the Interior.

I see also

U. S. Geological survey.