Magnesite deposits of Grenville district, Argenteuil County, Quebec [microform]

Wilson, M. E. (Morley Evans) · 1917 · Historical

View looking westward from rocky knob, on lot 25, range X, Grenville township, showing the Laurent View looking westward from rocky knob, on lot 25, range X

This 1917 document, Magnesite deposits of Grenville district, Argenteuil County, Quebec [microform], is preserved in the Mountain Man Mining Library for research and reference. Original source: archive.org.

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View looking westward from rocky knob, on lot 25, range X, Grenville township, showing the Laurent

Pirate I,

Laurentian topography of the district, the southern portion of Harrington flat, Rouge river, and the Bell pow-r ,.'ant.

View loo, Grenville township, showin

Canada Department Of Mines

How. Es. L. PATENAUDE, MINISTER; R. G. MCCONNELL, DEPUTY MINISTER.

Geological Survey

Memoir 98

No. 81, GEOLOGICAL SERIES

Magnesite Deposits of Grenville District, Argenteuil County, Quebec

OTTAWA GOVERNMENT PRINTING BuREAU 1917 No. 1685

Contents.

CHAPTER I. PaGE

Teri vOQ bet eh soos aa cc sig 0 os dare Fees cna ors oho 4 Woe vacele ccnlnrselelhiietaraiadleraiere's 1 General MGMEDE oad c cic cee deseo erees seceerenteeersenhe eee 1 JP ARSE pepe nono OOOO EHO Oo Ce GOUncC or Conicrotnnes Onur Bobor 3 Preparation of magnesite 06 cs cece eee e eee n ete eee e eens 4 Uses Of mia gresite. nc cit cnc cc veneers ttre nnntaie tings eteteess + Foreign sources of supply 0... sees cece eee e eee nen enenees 8

Austria-Hungary. ...5 000.0050 ccc ccc e cece ese ceceeenetonenerecervee 8

CR at eh EC ERE ARE SEE EE OPS eee eee CES 10

United: Staten 6 sc ov ieo vies 9 raw 8s wows Freee sos oreo neuen gerees ane 10

Other Canadian magnesite deposits 60. c ec ee eee e eee eee eens 14

PreiictiOtiee cs saviccccc ia rai eas ee Se TT eRe Tee Ee 16

History of magnesite mining in Grenville district ++ee00+ 17 a CHAPTER II.

General geology 02. .e cece eee e cect erect ence eee eeeen ence reeecees 19 General atetemeOt occ cc oc can heart Pele eG FeV aER MEO REEEE oe ee NN 19 Basal complex. 00sec cece cece cece erence eee eeeeneeeeeeeans 19

General statement ccc ccc c eect emer eteeeenseeceessens 19

CPORY NE COTIOE 5 ooo ons So sb ce calc side Sa ease se ROR eee HERE HS MeeT 20 Buckingham series 00sec eee een een eee nee een ees 20 Metamorphic pyroxenite 00.0 e cece eee e eee e eee e ees 21 Granite-syenite gneiss 06 cee eee eee eet e eee e eee n een enees 21

Late Pre-Cambrian intrusives 0.00 c cece eect teen ener eeeee 22

Ce eet Seen GR ae Tn NGO or od oO iae nes eae 22

; Tua ASe cei eee ee Oe eee REE rg Beem RIDER puslslasin as 22 Granite, quartz syenite, syenite, and quartz syenite porphyry 22

Pa lipolote 26 ovo cet oc ion sles oe sseie fee peat eetern ees muss 23 fe a oe A RES ar eer ee RO ICC iC CI 23

3 ft he drt adel Boy a AAS ORS nS Raia LOG PGR BOU COSCO eee 23 Marine clay and sand 00ecececec ence cee e ete e ee eentnteee 24

Chapter Iii.

Magnesite deposits 6c cece cece e cent e eee ence tenet n ete taes 25 Distribution and geological relationships... +++. esee eee renee 25 General chavactet 65555 .cc sc sicc eee nie at and an enue e nese 25 Se, SHORE te See Race ESET OCT TOC eo Topas Oe ea 26 EO TeaP ARSENE 5b cierate cesta ce tester crarotes rere esse no On ER RTE See avo Cueralo Hels 27 MABBFRIOEY . occ or ecciaecreseyer coer taste meme ses enestemevnu are 28 Cg 2) ee Ge OCIA ane DES OME Ora Pe Tee ne ee oO 30

Determination of lime content of magnesite and magnesite-dolomite 34 Explanation of tables and outcrop map8 660s secre e crete eee eee 35

Chapter Iv.

Descriptions of properties ccc ccc ccc cncueucueuaeucucucecs 37 Lot 13, range I, Harrington township, Dobbie mine 37 Lot 18, range XI, Grenville township, Shaw mine 38 Lot 15, range XI, Grenville township 0.0cccsccucucueees 41 Lot 15, range X, Grenville township 0.0 ccc ces eueeuee 51 Lot 15, range IX, Grenville township, McPhee property 52 Lot 13, range IX, Grenville township cc ccceeceuceeee 58 Lot 16, range IX, Grenville township 0.0ceccueeeeenee 59 Lot 11, range VIII, N. Grenville township, Campbell property 59 Lot 12, range VIII, IN. Grenville township 000. cc cee sues 59 Lot 11, range VIII, S. Grenville township 0000- 60 Lot 12, range VIII, S. Grenville township 00000e 60 Lot 9, range XI, augmentation of Grenville 00. ecu eeae 60 Lot 21, range I, Harrington township 0 ccc ceeeaee 61 Lot 7, range X, Grenville township 0 0 ccc cece ee eeee 61 CHAPTER V. Summary and conclusions 00cccccec cc cveccecceueceeeusenee 62 Illustrations. Map 1675 Diagram showing magnesite deposits, lot 15, range XI, Grenville township, Argenteuil county cceceseeeeees in pocket 1674 Diagram showing magnesite deposits, lot 15, ranges IX and X, Grenville township, Argenteuil county 0.. . 1679 Diagram showing magnesite outcrops, Grenville township, Argen- SOUT COUREY os iss cect ae oe eee OR ee £

Plate I. View looking westward from rocky knob on lot 25, range X, Grenville township, showing the Laurentian topography of

thin: Gistrict ics ate ne lesr nee nee a eee eee ee Frontispiece

II. Weathered surface of crumpled sillimanite-garnet gneiss and quartzite, lot 22, range I, Wentworth township 65

III. Banded crystalline limestone, exposed in bed of West river, lot 20, range I, Wentworth township 00ececeeeeees 67

IV. Knob of crystalline limestone containing nodular inclusions of pegmatite and pyroxene syenite, occurring east of the Scotch road,

lot 18, range IX, Grenville township 00.005 69 V. Granite gneiss interbanded with and intruding pyroxenic gneiss of the Buckingham series 00 cc eeceeeeeeeneeens 71 VI. Weathered surfice of magnesite-dolomite, lot 15, range IX, Grenville townships 57 ncos5 cece ese y chen er ioe an 73 VII. A. Calcined Grenville magnesite-dolomite 75 B. Calcined Grenville magnesite, showing inclusions of dolomite . 75 VIII. A. Calcined Grenville magnesite-dolomite 77 B. Grenville magnesite-dolomite calcined in a reducing at- Dg a a 77

IX. Disseminated grains of serpentinized diopside forming parallel

bands in Grenville crystalline limestone, Buckingham, Quebec 79 X. Kilnand mill, North American Magnesite Company, on the McPhee property, lot 15, range IX, Grenville township

et

Soe R Ld ag MP tn bnialaowhens onto iv

Plate XI. No. 3 pit, Scottish Canadian Magnesite Company

Figure 1.

Location of Grenville area 6.. cece cece e eee e eee eenes Diagrammatic section across south face of pit in magnesite deposit, lot 18, range XI, Grenville township 455

Magnesite Deposits of Grenville District, Argenteuil County, Quebec.

Chapter I.

Introduction. General Statement.

As a consequence of the present war the supplies of numerous mineral materials formerly imported into Canada and United States from abroad have been partly or completely cut off and for this reason special attention has been directed to the investigation of deposits of these minerals occurring on this continent. Among the minerals of this class one of the most important is the magnesium carbonate, magnesite, the world's supply of which was formerly derived almost entirely from deposits in Austria-Hungary and Greece. The restricted importation of this material, especially during a period of unprecedented activity in the metallurgical industries, has brought about a complete transformation in the market conditions in America for magnesite.

The almost complete dependence of the American consumer on foreign sources of supply of magnesite prior to the war and the readjustment which is now taking place is indicated by the statistics of importation and domestic production in the table on pages 12 and 16. In 1913, the year preceding the outbreak of war, 172,591 short tons of calcined magnesite and 22,872 tons of crude magnesite were consumed in United States, of which (only 9,632 tons of crude) less than 3 per cent was produced at home; whereas in 1915 the total consumption of magnesite in United States was 26,574 short tons of calcined and 80,267 short tons of crude, of which approximately 23 per cent was domestic production. Likewise, the production of magnesite in Canada inctvased from 515 tons valued at $3,335 in 1913 to 55,413 tons having a value of $563,829 in

Up to the present time (March, 1917) the increase in the domestic production in North America has been derived almost entirely from Canadian deposits situated a few miles north of Ottawa river in the Grenville district, Quebec, and from scattered occurrences in the state of California in United States. Though the Canadian magnesite contains more lime than the California magnesite and in that respect is of inferior

quality, in every other respect it has many advantages over the California product. Some of the most important of these advantages are the following:

(1) The Canadian deposits individually are much more extensive and easier to work than those in California.

(2) The California deposits taken as a whole are so limited in expert that even if worked to full capacity they could furnish only a small part of the magnesite needed in United States.

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Figure 1. Location of Grenville area.

(3) Since the principal manufactories consuming magnesite are situated in the eastern part of the continent and the freight rate for magnesite between California and Points in eastern United States is $10 per ton, the Canadian deposits are much more advantageously situated with respect to the magnesite market.

(4) The cost of labour is considerably higher in California than in Quebec.

(S) At the present time (March, 1917) the actual cost of Canadian magnesite laid down in the Principal magnesite markets of United States is from one-half to one-third less than that for California magnesite, a difference which will probably be further increased with the construction of tramways from the Canadian deposits to the railway.

1 Mineral resources of United Statec, pt. 2, 1914, p. 571,

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In view of the preceding considerations it is probable that for many purposes the California magnesite could not seriously compete with Canadian product in the eastern part of either United States or Canada, provided the Canadian deposits could supply the demand.

This memoir is a brief account of the results of an examination of the Grenville magnesite deposits made by the writer in the course of field work during the field season of 1916; supplemented in the introductory chapter by information of general interest to those engaged in the magnesite mining industry.

Magnesite.

Magnesite, the name usually applied to the carbonate of magnesia (MgCO;) as found in nature, is a chemical compound consisting of 47-6 per cent oxide of magnesium, magnesia (MgO), and 52-4 per cent carbon dioxide (CO,). It is somewhat heavier and harder than calcite, having a specific gravity of 3 to 3-12 and a hardness of 3-5 to 4-5. When free from impurities it has generally a brilliant snow white appearance, but in some of its occurrences, owing to the presence of disseminated impurities, it is yellow brown or grey in colour. Magnesite is almost insoluble in cold hydrochloric acid or sulphuric acid, but dissolves readily with effervescence in warm acids. When subjected to hieh temperatures a gradual decomposition of the mineral into magnesia and carbon dioxide takes place between temperatures of 300 and 600 degrees centigrade.! The resulting magnesia is exceedingly refractory, however, having a fusion point of approximately 2,500 degrees centigrade."

Deposits of magnesite are widely distributed throughout the world and are generally regarded as belonging to one or other of two types, the massive or the crystalline. Massive magnesite, the most common type, is a fine-grained compact variety usually found in veins or masses in serpentine which has resulted from the alteration of magnesia-rich rocks of the peridotite family. To this group belong the Grecian deposits, nearly all the deposits in California, the recently discovered deposits in Bridge River district of British Columbia, and numerous other deposits found in various parts of the world. The crystalline variety of magnesite has been so named because of its coarsely crystalline texture. The principal deposits of this class, so far discovered, are those in Austria-Hungary

1Brill, O., Ueber die Dissociation der Karbonate der Erdalkalien und des Magnesiumkarbonate, Zeitechrift f. Anorg. Chem. vol. 45, 1905, pp. 277-292. Grunberg K., Beitrag. zur Kenntnis der naturlichen kristallistierten Karbonate, des Calciums, Magnesiums

, Eisens and Mangans. Zeitschr. f. Anorg. Chem., vol. 80, 1911, p. 337. 23000° C. according to Moissan.

1910° C. " Goodwin-Mailey, Jour. Am. Electrochemical Soc. vol. 9, 1906, p. 89. 2500° according to O. Ruff, Zeitschr. Anorg. Chem., vol. 82, 1913, p. 373. 2800° " " C. W. 'anolt, Jour. Wash. Acad. Sc., vol. 3, 1913, p. 315.

and the Canadian deposits at Grenville. In both of these localities the magnesite occurs as masses in limestone or associated sediments which have been rendered crystalline by the intense metamorphism to which they have been subjected.

Preparation Of Magnesite.

Magnesite is usually marketed in one or other of three forms— crude, caustic calcined, and dead burned.

Crude Magnesite. Crude magnesite, as the name implies, is the crude magnesium carbonats as produced at the mine with merely as much of the serpentine, qu tz, dolomite, calcite, or other impurities removed as can be culled away in mining the material or by cobbing.

Caustic Calcined. When crude magnesite is calcined at a red heat (approximately 1,100 degrees centigrade') a product is obtained known as caustic calcined magnesite. This material consists of magnesia (MgO) in which about 2 to 4 per cent of carbon dioxide has been retained. It slakes in contact with water and combines with magnesium chloride to form a hard vitreous material known as oxychloride or Surel cement.

Dead Burned. If, on the other hand, magnesite is calcined at a white heat (approximately 1,700 degrees centigrade)? a product known as dead burned magnesite is obtained. This material contains less than 1 per cent carbon dioxide, is exceedingly refractory, and chemically inert. It does not slake in air or in water, but tends to disintegrate in contact with steam.*

Uses Of Magnesite.

The peculiar and v ried properties of magnesite and its derived products have led to its use in a great variety of industries. Among the most important of these industrial applications are the following:

Refractory Material. Owing to the high fusion point and chemical inertness of the oxide of magnesium, magnesite is one of the principal minerals used in the metallurgical and other industries where highly refractory material is required. For this purpose dead burned magnesite is generally used either in the form of brick or sand. As brickit is used for lining open-hearth steel furnaces, welding, heating, and melting furnaces, copper converters, electrical furnaces, reverberatories, settlers, ar races for refining lead. In the crushed form, it is used for lining

bottoms of open-hearth furnaces, for lining rotary kilns, and in making

cibles and cupels. Caustic calcined magnesite is also used to a limited

1 Morganroth, L. C., Bull. / Min. Eng., No. 93, 1914, p. 2351. 2 Gowling, W., "The meta": - the non-ferrous minerals," 1914, p. 10. & According to R.H. Youngu. etal. and Chem. Eng., vol. 12, 1914, p. 620.

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extent a: u refractory material in fireproof paint, and in mixtures with crude magnesite and other material in furnace !inings.

Recently the Steel Company of Canada, has been using calcined Grenville magnesite mixed with 10 to 40 per cent furnace slag as a lining for npen-hearth steel furnaces, with satisfactory results. The chemical composition of the slag is as follows:

OWNS fice sins MaDe dines Liekedb vee ied Sea wE RR Re 9-81 fo eae Br cate fs trey Bye heyy oe Pte cet 1-78 Oxide of iron . 17-29 MR cacaleeiek 8a Raw Tee TEOT ERS CO ERETTT $1-97

DE Cub dakar cite cle necesito eis . 6-74 Phosphoric acid 2-70 BURR, oriccen cic ha Kone aaine tae eee 0-247 Cele GE ANNE, cons hos on se eedasaune a. 5-67

The ma..ner in which the mixture is prepared and placed in the furnace is as follows:

The crude magnesite as it arrives from the mine is calcined for eight hours in a furnace holding approximately 9 tons of the crude material, about 3 tons of coal being consumed in this operation. The calcined magnesite is then broken down with hammers to fragments one-half inch or less in diameter and mixed with the crushed slag in proportions ranging from 15 to 40 per cent slag and 85 to 60 per cent magnesite.

When a furnace is to be lined it is heated to a temperature above the melting poin: uf the slag (2,700 degrees to 2,800 degrees Fahrenheit), and small charges of the mixture of slag and partially calcined magnesite are thrown in and spread out uniformly over the furriace bottom at intervals of 15 minutes. In this manner the lining is built up on the furnace bottom to the depth required. If carefully laid and intimately mixed this bottom will last for a considerable length of time without repair, and is equal in every respect to bottoms prepared from Austrian magnesite.

Prior to the present war it was stated by manufacturers of magnesite brick generally that refractory brick could not be manufactured from magnesite containing more than a very small percentage of lime, but the following analysis of a magnesite brick obtained from one of the principal purchasers of Canadian magnesite seems to indicate that such is not the case, and that Grenville magnesite is being used in large proportions, if not entirely, for this purpose.

SiO; F e202 Al,O; CaO M gO 10-26 6-67 2-98 8-70 71-75 — loss on ignition 0-05

It is also reported that a mixture of dead burned Grenville magnesite, caustic calcined Grenville magnesite, and magnesium chloride is now being satisfactorily employed as a furnace lining to replace magnesite brick.'

4 Roast, H. J., "The development of Canadiap magnesite,'' Annual meeting, Can. Min. Inst., 1917.

Oxychloride or Sorel Cement. A mixture of finely ground caustic calcined magnesite and magnesium chloride known as oxychloride or Sorel cement has been used extensively in recent years as sanitary flooring, stucco, artificial marble, tile roofing, and other structural material. The use of magnesite for this purpose is based on the fact that when wet with a solution of magnesium chloride of a certain concentration it sets as a hard vitreous cement. As a flooring, this material when properly mixed and laid is much superior to any other variety of cement. It can be coloured, takes a good polish, is waterproof and fireproof, and does not pulverize to dust. Certain practical difficulties have been encountered, however, in procuring a raw material of uniform quality and in consequence the floors have not always been satisfactory. In practice it is generally customary to add certain materials such as wood, serpentine, talc, ,round quartz, asbestos, and other substances to the mixture as filler, the resultant mixture being sold under a great variety of trade names such as artificial marble, asbestolith, asbestos floors, composite, compostone, kellastone marbeloid, monolith, petrified wood, sanitary f'->rs, scagliola, stonewood, tileine, and velvetile.

Manufacture of Wood Pulp by the Sulphite Process. Considerable amounts of magnesite are consumed in the manufacture of chemically prepared wood pulp, for use in the manufacture of paper. The preparation of wood pulp by this process consists in boiling the wood with a chemical reagent which will serve as a disintegrating agent. For this purpose either sulphurous acid or calcium or magnesium bisulphite are generally used. The magnesium bisulphite is generally preferred, however, because of its greater stability and because of its greater solvent action on wood resins.

Manufacture of Carbon Dioxide. Considerable quantities of carbon dioxide were formerly manufactured from magnesite, but limestone or coke is now generally used for this purpose. Carbon dioxide is manufactured from crude magnesite by calcination and the recovery, purification, and compression of the carbon dioxide gas evolved, the residual caustic magnesia being sold as a by-product. In practice it has been found, however, that in order to obtain the most efficient results in the manufacture of carbon dioxide the crude magnesite has to be calcined at a lower temperature than that required to produce caustic calcined magnesite, that is, the residue contained too much carbon dioxide. On this account the use of magnesite for the manufacture of carbon dioxide is decreasing.

Since the calcination of the crude magnesite effects a reduction in weight of nearly 50 per cent it has been generally found te be more economical to calcine the magnesite at the mine and red"e the cost of shipment, and usually no attempt is made to save che carbon dioxide in this operation.

"Cold Water" Paint. Because of its refractory qualities caustic calcined magnesite is now used in the manufacture of fireproof paint. For this purpose a finely ground mixture of caustic calcined magnesite and magnesium chloride is prepared and is mixed with cold water for eonlication.

Metallic Magnesium. Prior to the war the world's supply of metallic magnesium was largely produced in Germany where it was manufactured from m~~nesium salts obtained from the salt deposits at Stassfurt. It is now being produced in considerable quantities in France, England, United States, and Canada. Owing to the increased demand for the metal for military purposes and restricted importation the price of magnesium rose rapidly in United States after the outbreak of the war from $1.40 per pound to $5 to $10 per pound in 1914. During 1915 the prevailing price in New York was $5 per pound, but it has since fallen considerably, present quotations being $3.50. The importation of magnesium into United States before the war according to the statistics of the Department of Trade and Commerce was 38,000 pounds per annum. This, according to Dr. W. M. Grosvenor,' was considerably less than the actual consumption, the magnesium being imported by some manufacturers under other names. The normal consumption in United States for domestic purposes is stated by Dr. Grosvenor to be 50,000 pounds per year, an amount approximately equivalent to 90,000 tons of crude magnesite. The total production of ..ctallic magnesium in United States in 1915 was 87,500 pounds valued at about $440,000.*

The usual process employed in Germany for the manufacture of magnesium was by the electrolysis of the fused double chloride MgCl, Kel. It is said that it can also be made by the following processes: the reduction of magnesium chloride with metallic sodium; the reduction of the oxide with carbon; the electrolysis of magnesia; the reduction of fused chloride with aluminum; the reduction of the oxide or carbonate to slag forming residues; and other processes.®

In Canada, metallic magnesium is now being manufactured electrolytically from magnesite by the Shawinigan Electrometals Company at Shawinigan, Quebec. The details of the process :mployed have not been published, but Canadian maynesite is being employed® as the crude material.

The principal use of metallic magnesium is as an alloy with aluminum (magnalium) copper, nickel, zinc, lead, iron, bismuth, and other metals.

' Metal. and Chem. Eng., vol. 14, 1916, p. 262.

9U.S. Geol. Surv., Mineral Resources, 1915, pt. I, p. 737.

Greaveror, Dr. W. M., Metal. and Chem. Eng., vol. 14, 1916, pp. 262-264.

"Stanefield, Dr. A., 'Electric furnaces as applied to non-ferrous minerals," Min. Jour. (Lond.) vol. 113, 1916, pp. 233-234.

Letter froin Dr. A. Stansfield.

Of these alloys, that with a!uminum has been found to be exceptionally valuable. An addition of 2 per cent of magnesium toaluminum doublesits tensile strength, quadruples its resistance to jar or shock, and reduces its cost of machining over 50 per cent.! Magnesium is also used for scavenging alloys and for the illumination in flashlight photography and fireworks, and for military purposes in star shells, shrapnel trailers, etc.

Magnesium Sulphate. Large quantities of magnesium sulphate (Epsom-salt) are consumed in United States and Canada annually, the larger part of which prior to the war was imported from Germany, where it was produced as a by-product from the Stassfurt salt deposits. It can also be manufactured by treating magnesite or dolomite with sulphuric acid and is produced in this manner in United States. Magnesium sulphate is used chiefly for medicinal purposes, in tanning leather, in cotton manufacture, and in chemical laboratories.

Magnesium Chloride. The magnesium chloride consumed in America was formerly imported almost entirely from Germany, but is now being produced in United States by treating magnesite or serpentine with hydrochloric acid. It is also obtained as a by-product from the bitterns of salt refineries. Magnesium chloride is used in the manufacture of oxychloride cement, in the manufacture of cold water paint, in the manufacture of cotton goods, and in chemical laboratories.

Light Magnesium Carbonate (magnesia alba levis). The light or basic magnesium carbonate (MgOH, 3MgCO;) can be prepared from magnesium sulphate or chloride, but is also manufactured from magnesite and dolomite. This product is used as a toilet preparation, for medicinal purposes, and as a heat insulator on boilers, pipes, etc.

Miscellaneous Uses. There are numerous other minor uses to which magnesite and its derivatives are applied. It is used as carbonate to prevent scale in boilers, where sulphurous waters are used; as carbonate in tooth paste; as oxide in dynamite; as oxide in the rubber industry, and as hydrate (milk of magnesia) for medicinal purposes.

Foreign Sources Of Supply.

Although deposits of magnesite are known to occur in numerous localities throughout the world, the principal part of the world's production, prior to the war, was derived from only two countries, Austria- Hungary and Greece. The deposits in United States are also of interest in this connexion, however, since a large part of the mag.site mined in Canada is exported to that country.

Austria-Hungary. Magnesite is known to occur in numerous widely scattered localities in Austria-Hungary, but the deposits on which mining operations are being carried on are limited to the central part of

1 Grosvenor, Dr. W. M., Metal and Chem. Eng., vol. 14, 1916, p. 263.

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the province of Styria (Steigermark) in Austria and to northwestern Hungary. In the first locality the most important deposits occur near the town of Veitsch. The largest deposits in northwestern Hun,ary lie between the towns of Jolsva and Nyusta.

The magnesite found in Austria-Hungary is mainly a grey to drab variety, occurring in association with talc, quartz, dolomite, calcite, pyrite, and other minerals as enormous lenticular masses several hundred feet in diameter. The larger part of the impurities contained in the magnesite are removed in practice by cobbing at the mine and by sorting after the product has been calcined; so that except for the iron which it contains a magnesite of a fair degree of purity is produced. It is said that the Austro-Hungarian magnesite, owing to the iron which it contains, is more readily reduced to the dead burned state and that the iron oxide contained in the product serves as a binder in making furnace linings and in the manufacture of magnesite brick, and that on this account, except where a more highly refractory material is required, Austro- Hungarian magnesite is preferred.!. Analyses follow:

I TT Ill IV Vv

SiO, 0-45 0-76 5-83 0-74 0-74 0-76 AlOs tance 0-14 0-48 0-39 0-39- 0-27 Fini 3-65 5-72 1-54 3-27 3-27- 3-43 Mn,O; trace 0-94 aoe Ae

CaO 0-97 0-32 4:52 0:20 1-20- 0-90 MgO 43-82 43-06 39.54 44-80 44-80-45-00 CO; 50-44 49-81 47-99 50-10 50-10-50-20

I. Veitsch, Fortschritte der Min., Krist. und Pet., vol. 4, 1914, p. 29. II. Britenau, oe se a a 9

III. Dienten, Eicheiter C. F., Jahrb. d.k.k. geol. R.A., 1907, p. 927. IV. eae Fortschritte der Min., Krist., und Pet., vol. 4, 1914, p. 32. yustya, Bull. 355, U.S.G.S., 19€8, p. 56.

Because the Austro-Hungarian magnesite deposits are closely associated with Palaozoic marine sediments it was formerly assumed that the magnesite was of sedimentary origin; but the closer study of the deposits during recent years has lead to the conclusion that they are in reality metamorphic deposits formed by the action on Palzozoic limestone? of magnesium carbonate solutions, derived from basic intrusives.

' Morganroth, L. C., "The occurrence, preparation, and use of magnesite,' Bull. Am. Inst. Min. Eng., 1914, No. 93, pp. 2345-2352.

Rumpf, J., 'Ueber kristallisierte magnesite aus den nordéstlichen Alpen, Tschermak's Mineralogische Mitt., 1873, p. 263.

Weinschenk E., Grunzuge der Gesteinskunde, Freiberg vol. 2, 1905, p. 315. Redlich, Karl A., Fortschritte der Min. Krist. und Pet. vol. 4, 1914, pp. 9-42. Kern, A., Der Magnesit und Seine technische Verwertung, Gliichauf, 1912, pp. 271-275.

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eon SiSthekt tented

iets ir

Gar Ses aes bi 3 fet hoad

The quantity of calcined magnesite exported from Austria-Hungary during the years 1909 to 1913 was as follows: Metric tons.

yt Ree mare Sey eNO ear ONE RCE OTD 125 ,666 TCA (1 Werk pia one rer Mrontich tc odor wma OR 182,911 (OER: 6 ooo cert teen Pesta aden beeen ese s 147,481 VO ee eet eee bce inten ATER 6 Pe pnb ner ice EE CEG ERC 171,196 SOF ore vara asian Neate a Ree eee ke 200,947

Greece. Magnesite is found at a number of localities in Greece, but the important deposits are situated on the island of Euboea, where it occurs associated with serpentine in numerous masses and veins up to 50 feet or more in width and several hundred feet in length. The magnesite is of the massive variety and contains the usual associated quartz, dolomite, and other impurities. The larger part of these are cobbed out in mining the material, however, so that a product of exceptional purity is produced. Analyses follow:

Analyses of Typical Grecian Magnesite.

Ts Ear eM ener nae. 0-20 0-90 0:38 1-63 [7 ate RET Se 0. 20) peer {0-18 0-17 Bese. pcos ad tan wale ies oo 0-20 0-08 1-19 Pee cites aes 0-51 1-53 1-68 1-44 Mi i ee 47-11 45-45 46-09 45-75 EERE ESOT 377 51-26 51-51 49-88

Fea os casc one 98-99 100-00 99-89 100-06

J

Since the Euboean magnesite deposits are all situated in close proximity to the seashore, under normal conditions Grecian magnesite has the advantage of cheap water transportation to the principal magnesite markets of the world. Production was as follows:'

Production of Magnesite in Greece for the Years 1911 to 1913.

long tons long tons net tons Crude: vce arsenate 27-892 36°519 o 517 Gnlemetian eee 22-987 30-645 31-815 Dead burned... nec os 6-422 §-408 cee

United States. Magnesite is known to occur in numerous localities in United States, but the only deposits of sufficient extent to be of com-

'Hogg, James, Trans. Inst. Min. Eng., vol. 46, 1913-1914, pp. 128-148. 2 Rousch, G. A., Mineral Industry, 1914.

mercial importance, so far discovered, occur in the state of California.! There they are found in numerous widely scattered localities throughout the coast range and on the western slope of the Sierra Nevadas, extending from Mendicino county in the north to Riverside county in the south, a distance of approximately 500 miles. Deposits of considerable size are said to occur in eleven different counties in this territory, but up to the outbreak of the war mining operations on most of the properties had scarcely passed the prospect stage. The most important deposits are situated in Tulare, Sonoma, and Santa Clara counties, a considerable part of the total production of the state being derived from deposits in the vicinity of Porterville, Tulare county.

With the exception of certain deposits of magnesite near Bissel in Kern county, which occur associated with clays and clay shales and on that account are regarded as of sedimentary origin, all the Californian magnesite deposits occur as irregular veins, masses, or stockworks in serpentine resulting from the alteration of magnesian igneous rocks. Though in some localities veins and masses of magnesite 20 feet or more in width are ~esent, most of the deposits consist of numerous . nall veins; and, in consequence, a considerable portion of the material mined requires hand sorting and the proportion of waste rock is large.

The chemical composition of typical samples of Californian .nagnesite 1s indicated in the following table:

Chemical Analyses of Californian Magnesite.

SNC ree ae etalon 2-28 7-67 Alumina 0-03 0-26 Betric:oxides c.. 8 aesn ite ca 0-26 0-29 PME esr trace Gok Rae 1-32 0-04 Nagnesifintsctecct 45-17 43-42 Carbon dioxide 50-74 48-08

ORB rnin eee ners 99-80 99-76 99-61

1s Porterville, Tulare county, Bull. 355, U.S.G.S., 1908, p. 56.

II. Red Slide, Sonoma county, Bull. 355, U.S.G.S., 1908, p. 26.

III. Red Mountain, Santa Clara county, Bull. 355, 1908, p. 36. IV. Near Winchester, Riverside county.

The preceding analyses indicate that in chemical composition the Californian magnesite differs little from the Grecian magnesite; but the higher cost of production and transportation has made it difficult for e Californian magnesite to compete with the Grecian product even on

' Deposits of magnesite of possible commercial ii .portance have recently been reported to occur near St. Thomas in Clark county, Nevada, and in the northern part of the state of Washington. Eng. and Min. World, vol. XLIV, 1916, p. 482, and Eng. and Min. Jour., vol. CIII, 1917, p. 601.

the Pacific coast of United States, considerable Grecian magnesite being sold there annually in competition with the local output. The price of Californian magnesite in San Francisco during the years preceding the war ranged from $8 to $12 per ton for crude, and from $25 to $30 per ton for unground calcined, and from $35 to $40 for ground calcined; during the same period Grecian magnesite sold f.o.b. New York at $7 to $8 per ton for crude, $17.50 to $20 per ton for unground, and at $25 to $30 for ground. Since the principal industries in which magnesite is used are situated in the eastern part of United States, and the freight rate between the Pacific and Atlantic coasts is $10 per ton by rail, and $7 per ton by water, it is impossible for the Californian magnesite to compete with the foreign product in the eastern market under normal conditions.

The production of magnesite in United States for the years 1911 to 1915 inclusive, as given in the report of the United States Geological Survey, was as follows:

Short tons. Value. 13 0 Operon Merete cst ere eC eo 9,375 $16,326 SOT Bera re on see ea es 10,512 84,096 TU) 6 re eae ORO COE Eines 9,632 77,056 $016 oe ov cag Rew eeneenioans 11,293 124,223 BOTS ioc scoceits sueve's eer rT 30,499 274,491

The importation of magnesite an] magnesia for the years 1911 to 1915 as given under these headings in the rene ut the United States Department of Commerce was as follows:

SEs ara ERT TS Re eB

160'9L Sire Wise Are w $20'ZZ1 ° 'paytaind jou paursye)

Oll 601 'T

$06' L1 zsz'Szt

978 '401 eee' soz' T

'#8 OFZ' eT $9S'ZL9'T] 660'L9T

PSE' ET LI8'TZt

; : ' ajtsaudopy ¥88 CE 790 % 6fL IF 6SS'7Z S16'Z azeydjng 088 F se L7L'Z 198°Z 4 **([eutstpaut) ayeuoqie}) ¥£0 OT LZ 97zE OT $69''ET oF "*'*([eulIpaul) paursjey

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Other Canadian Magnesite Deposits.

The occurrence of magnesite in numerous widely scattered localities in Canada is recorded in the reports of the Canadian Geological Survey, but the meagre information given with regard to most of the occurrences indicates that most of the deposits are of too limited extent or are too remote to be of commercial importance. In New Brunswick a vein of magnesite several feet wide is said to occur in grev chloritic schist on the bay shore of St. John county near West Beach.! In Quebec, magnesite is found (in addition to the Grenville district) associated with serpentine and talc in Sutton and Bolton townships, Brome county. One of these deposits on lot 17, range IX, Bolton township," is stated to be 20 yards wide. In Ontario, a blue ferruginous magnesite occurs in association with finely crystalline pyrite on Lac des Mille Lacs,' Algoma district. In British Columbia, the presence of magnesite is recorded at IIlecillewaet in the Kootenay district,4 on Germansen creek in the Omineca district®, at 108-Mile House on the Caribou road in the Lillooet district,® and in the vicinity of the town of Atli:. in the Atlin Mining Division.?. In Yukon Territory ferruginous magnesite was observed by Mr. R. G. McConnell on Big Salmon river, a tributary of the Lewes river, and on Yukon river about 14 miles above the outlet of Indian river. In the first mentioned locality the magnesite occurred in a band 50 feet thick in association with dark, partly altered slates, greenish schists, and serpentine.® Magnesite is also reported to occur in sedimentary beds on the Yukon-Alaska boundary north of Porcupine river.®

In the Atlin Mining Division of British Columbia both magnesite and hydromagnesite were observed by Gwillim, but the extensive masses of hydromagnesite occurring in the vicinity of the town of Atlin are the most important. These deposits are superficial beds of fine powdery white hydromagnesite having a thickness ranging from 8 feet to 6 feet and covering areas up to 18 acres in extent.!

Analyses of this material made by Mr. N. L. Turner of the Mines Branch gave the following results:

1 Bailey, L. W., and Matthews, G. F., 'Preliminary report on the geology of southwestern New Brunswick,'' Geol. Surv., Can., Rept. of Prog., 1870-1871, p. 237.

2 Geology of Canada, 1863, p. 457.

Geol. Surv., Can., Ann. Rept. new ser., vol. IX, 1896, p. 95 S.

3 Geol. Surv., Caa., Ann. Rept., new ser., vol. I, 1889, pt. M., p. 22,

4 Geol. Surv., Can., Ann. Rept., new ser., vol. 1X, 1896, p. 96S.

§ McConnell, R. G., 'Report on an exploration of the Findley and Omineca sieana Geol. Surv., Can., Ann. Rept., vol. VII, 1894, p. 25.

Geol. Surv., Can., Ann. Rept., vol. II, 1898, p. 10.

7 Gwillim, J. C., Geol. Surv., Can., Ann. Rept., vol. XII, 1899, p. 72A and p. 46B.

§ Geol. Surv., Can., Ann. Rept., vol. II, 1898, pp. 16-17R.

®Cairnes, D. D., Geol. Surv., Can., Sum. Rept., 1911, p. 33.

1 Young, G. A., Geol. Surv., Can., Sum. Rept., 1915, pp. 50-61.

nes

runstise

Randle. 20

Analyses of Hydromagnesite from Atlin, B.C.

WON scat ede eraaees 1-86 0-90 0:54 0-74 0-96 10, ei erate bert ean crates 0-67 6-10 0-17 0-35 0-23 Uo CeR Ape pine coon eeerar 0-15 0-09 O-11 0-15 0-12 FeO.. 0-60 0-45 0-64 0-60 0-53 CAO sees iss 2-04 0-82 0-68 0-32 0-16 MgO cei sare eninitn ret 41-13 42-35 42-19 42-85 43-04 (ool 2 ee tre earn ear ee 35-98 36-10 36°17 36°35 36:21 H,0 + 18-02 18-95 19-05 19-10 19-26 RRL domser ere aR 100-45 09-76 99-55 100-52 100-51

PR eee Sat cic Sages wicinane 92 1-61 1-35 1-21 9-34

A number of hypotheses to account for the origin of the hydromagnesite have been proposed by those who have studied the deposits in the field. Gwillim suggested that the material has been deposited from springs, an hypothesis which seemed to be supported by the results of analyses of water from the springs of the district, since these were found to include considerable magnesia. Robertson', who examined the deposits in 1904, concluded, however, that the hydromagnesite was a product resulting from the weathering of magnesia-rich rocks directly underlying the deposits. Young', on the other hand, pointed out that the deposits have not the tuffaceous structure of spring deposits and do not rest on magnesia-rich rocks but on soil, and concluded, therefore, that there are valid objections to the hypotheses of Gwillim and Robertson, and suggested that the hydromagnesite represents material deposited on the bottoms of ponds which have disappeared since the deposition occurred.

It is estimated by Young that two groups of deposits occurring in the outskirts of the town of Atlin contain approximately 180,000 tons of hydromagnesite.

Recently C. W. Drysdale' has discovered magnesite near the northwest end of Liza lake in Bridge River district, Lillooet mining division, British Columbia. The magnesite found in this locality is a buff yellow massive variety occurring as masses and veins in serpentinized magnesian rocks and is thus similar in character and origin to the deposits of California.

1 Robertson, W. F., Rept. of Minister of Mines, B.C., 1915, pp. 82-83. ? Geol. Surv., Can., Sum. Rept., 1915, pp. 55-61. 3 Geol. Surv., Can., Sum. Rept., 1915, p. 83, and 1916, p. 48.

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Analyses of the magnesite made by Mr. N. L. Turner of the Mines Branch resulted as follows:

Axalyses of Magnesite from Bridge River, B.°.

0 Saar ae erences: moon nor 7-46 4:08

a ah iene ie Rale Dale ETRE LOIRE SERRE US UES 2 . 0-59 (73 ee aledem em Uperan ee Ward Sark LoTR LEME ee eI +56

jf oh ey ee CNT era e eye Cee eee ee ee 0-25 0-95

CRO eae nets ARP RE ee ree OU sale TIED 0-46 3-25

) Po aire on rokdtnririetin gn ite oly on see ar Ge, 43-42 42-20

COR re. certs Ree et cna i ite eGo s Buea eNe Ca GG 47-28

3 ae Ae ee ty fone ce ee ere ea. 0:58

H,O SD eee mee HeH HEHEHE HEHEHE HHH HS HOES HHESFPNO SOS 0 10

J Ra at Sie ar Pees er iene rity ae ree" 100-34 99-62

The outcrop from which the above representative samples were taken measured 52 feet by 48 feet, indicating that the deposits are extensive. 'They are situated at a distance of over 30 miles from the nearest point on the Pacific and Great North-Eastern railway, however, and are, therefore, too remote to be profitably mined at present.

A deposit of magnesite has recently been discovered near Orangedale, Inverness county, Cape Breton island. The magnesite is a brown crystalline variety having the following composition:

SiO Al.O; Fe,0; M gCO; CaCO, 0-30 1:01 1-71 90-80 2-85 Total, 96-67

When visited by A. O. Hayes of the Geological Survey in the summer of 1916 an outcrop about 100 square feet in area was exposed, protruding through sand and clay. Since that time 30 tons of magnesite have been mined from the deposit by the Nova Scotia Steel and Coal Company which has acquired possession of the property.

Production.

The production of magnesite in Canada since the year 1908 as compiled by the statistical division of the Department of Mines is as follows:

Year. Tons. Value.

TOG So So saiwieencxax 120 840 Pa? Pacer tree pire) Cicks 330 2,508 hr eo ae 323 2,160 Sty y Demers aoereeeanr 991 §,531 Lg a rine ria 1,714 9,645 a he eee ee 515 3,335 T9TG oe ee ees 358 2,240 Teas ee eee 14,779 126,584

mer ling een any

as s is

History Of Magnesite Mining In Grenville District.

In the month of June 1900, Reverend W. P. Boshart in the course of a visit to Mr. Donald McPhee, lot 15, range IX, Grenville township, observed a boulder lying a short distance from Mr. McPhee's house which had a whiter and more glistening appearance than the ordinary crystalline limestone of the district. He sent a specimen of the material to Mr. W. B. McAllister of Ottawa, who took the sample to the Geological Survey where it was determined to be magnesite. Learning that magnesite was of commercial value, a search for the mineral in place was undertaken by Messrs. McAllister and Boshart with the result that outcrops and boulders of similar material were found in numerous localities in the district. Later in the season Mr. R. L. Broadbent of the Geological Survey visited these localities and collected samples which were analysed by Mr. F. G. Wait of the section of chemistry and mineralogy of the Geological Survey. The results of these analyses were published in the report of the Geological Survey for .)00.!

Following the discovery of the magnesite, Messrs. McAllister and Boshart procured options on a large part of the territory in which the magnesite was known to occur, and made trial shipments of the material to consumers of magnesite, but the prices offered were too low for profitable operation, and no further attempts were made to market the material until the year 1907, when Mr. T. J. Watters purchased the mining rights for the north half of lot 18, range XI, Grenville township, from the Government and organized the Canadian Magnesite Company to operate the property. Later this company also acquired the mining rights for lot 15, range IX, Grenville, from Mr. McPhee, and erected a 10-ton keystone kiln on this lot for the purpose of calcining the magnesite at the mine, thus reducing the cost of haulage to the railway at Calumet, 11 miles distant. Mining operations were continued by the Canadian Magnesite Company on lot 15, range IX, in a small way, until the year 1914, when the property of the Canadian Magnesite Company was taken over by the North American Magnesite Company. Since that time mining has been actively prosecuted, both crude and calcined magnesite being shipped.

In 1915 Mr. S. Melkman of Montreal organized the Scottish Canadian Magnesite Company to mine magnesite on lots 15, ranges X and XI, Grenville township, under contract with the Grenville Lumber Company, to which these properties belonged. Magnesite mining was commenced in the month of August, 1915, by this company and has been continued up to the present. Since that time the Scottish Canadian Magnesite Company has acquired the controlling interest in the Grenville Lumber

' Geol. Sur., Can., Ann. Rept., vol. XIII, 1900, pt. R., pp. 14-19

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Pic ciesingi topline Fine Get Miwon sj eds l Abgndais aidetaeereas

Company and has constructed a light railway 14 miles in length connecting their deposits with the C anadian Pacific railway at a point about 2 miles east of Grenville station.

In October 1916, Mr. A. Lannigan and Mr. J. Milway of Calumet discovered a deposit of magnesite on lot 13, range I, Harrington township, which has since been acquired and operated by the International Magnesite Company of Montreal.

Some development work on magnesite prospects has also been performed by Messrs. Boshart and Fitzsimmons during the past year and a few tons of magnesite shipped. The larger part of these shipments were derived from boulders, however, and not from the magnesite in place.

Dempsine hit ahib ahaa

Chapter Ii. General Geology.

General Statement

The rocks occurring in the Grenville district when classified in a general way according to their age and structure fall int~ four definite groups:

(1) A basal group of Pre-Cambrian rocks which have all been more or less deformed and metamorphosed.

(2) Intrusive igneous rocks of late Pre-Cambrian age.

(3) Approximately flat-lying sandstone shale and sandstone of early Palwozoic age.

(4) Unconsolidated gravel, sand, and clay of Pleistocene and Recent age.

Arranged in tabular form the succession of formations in the district in detail is as follows:

Table of Formations.

Quaternary Champlain ] Marine clay and sand. Glacial... recs Re oad at Boulder clay, gravel, and sand Palzozoic ae CRESH: coc ie ect see nea Sandstone, shale, and limestone. Beekmantown Limestone. ae eo aan en yee es eee Sandstone. Late Pre-Cambrian .. ee Sea ee ree er eee quartz sventte,, syenite. Diabase. Sie Early BrecCambeiaitsstcc-. eas nox acai ore ' Granite-syenite gneiss. Metamarohie pyroxenite. " Buckingham (igneous) series...) Pyroxene syenite.

Pyroxene diorite. Pyroxene gabbro. Pyroxenite.

Grenville series Quartzite, garnet-sillimanite gneiss, c1_ talline limestone.

Basal Complex.

General Statement. The basal con:plex, the oldest of the four great groups into which the rocks of the Grenville district have been subdivided, is composed of a heterogeneous assemblage of sedimentary and igneous rock types

aera ara eee a ss laamase tate

sei It

posse bebe

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rs noryes ses onset

which, though not all coutemporaneous in age, have all been partly or completely transformed to a crystalline or foliated condition as a result of the regional metamorphism to which they have been subjected. In this respect they are strikingly in contrast with the rocks that succeed them in that the latter are not metamorphosed and retain all the characteristics by which they were originally distinguished. If classified merely on the basis of age, the rocks of the complex must be regarded as belonging to only three groups: (1) a group of recrystallized marine sediments cc 'stituting the Grenville series; (2) a group of igneous pyroxenic rocks of intermediate composition intruding the rocks of group 1, constituting the Buckingham series; and (3) batholithic masses of granite and syenite gneisses intrusive into the rocks of groups 1 and 2. sut the metamorphic action of the pyroxene gneisses of group 2 on the limestone member of the Grenville series has transformed considerable masses of this rock into diopside and related minerals forming a fourth common rock type generally known as ''pyroxenite."

The rocks of the Grenville series, being the least resistant to erosive agencies of all the rocks in the district are generally found to underlie the valleys, whereas the granite gneisses which are least easily eroded, form all the prominent hills (Plate I).

Grenville Series.

The oldest rocks recognized to be present in the Grenville district belong to what is generally known as the Grenville series. It is believed that the rocks of this series were originally laid down as alternating beds of shale, sandstone, and limestone, but, owing to the intense metamorphism to which they have been subjected, the shale has been recrystallized to sillimanite-garnet gneiss (Plate II), the sandstone tu v .treous quartz, and the limestone to crystalline limestone (Plates III and IV). The reasons for this conclusion are: (1) chemical analyses of the sillimanite-garnet gneiss member of the series show that this rock has in every detail the chemical composition of a shale and thus the three rock types, sillimanite-garnet gneiss, quartzite, and crystalline limestone have respectively the composition of the three dominant members of marine sedimentary series of the well sorted types, and (2) these rocks occur interstratified with one another in a manner similar in every respect to the way normal marine sedimentary deposits usually occur.

Buckingham Series.

The Buckingham series is a group of igneous pyroxenic rocks found widely distributed throughout the Pre-Cambrian of southern Quebec and eastern Ontario. In the district where the series was originally deswabtir

cribed members of the series occur ranging in composition from pyroxene granite to peridotite; but in the Grenville district only pyroxene syenite, pyroxene diorite, pyroxene gabbro, and pyroxenite were observed. These have been intruded in the Grenville series partly as thin bands injected between the beds or along the planes of foliation and partly as large lenticular bosses. Since their intrusion they have been subjected to intense deformation and are generally re or less foliated, the gneissoid structure being especially well developed in the thin Jit par lit injections.

Metamorphic Pyroxenite.

The rocks of this class generally occur as irregular discontinuous masses or bands, elongated in the direction of the strike of the garnet gneiss, quartzite, limestone, pyroxenic gneisses, and other rocks with which they are associated. The pyroxenite in its most typical occurrences is mainly composed of a pale green to white massive or granular pyroxene having approximately the composition of diopside, throughout which red or blue microcline commonly occurs as scattered crystals or in pegmatitic masses. With the pyroxene are associated a great variety of other minerals of which the following are the most common: scapolite, calcite, phlogopite, apatite, tourmaline, green amphibole, pyrite, chalcopyrite, titanite, fluorite, quartz, and prehnite. These minerals may occur as individual crystals scattered through the pyroxenite, as encrustations on the walls of geodal cavities, as inclusions in calcite, or as irregular veins. From the study of the character and relationships of the pyroxenite in the Grenville and other districts it has been concluded that this rock is a secondary type, formed from the crystalline limestone of the Grenville series by the action of pegmatitic solutions derived from the intrusives of the Buckingham series.

Granite-Syenite Gneiss.

The granite and syenite gneisses composing the third member of the basal complex are the most widespread of all the rocks found in the district, occurring as enormous batholiths and small masses and bands which have intruded their way through the rocks of the Grenville and Buckingham series. Lithologically, the granite and syenite gneisses are pink to grey rocks consisting of granular feldspar or granular feldspar and quartz with biotite or hornblende or biotite and hornblende together as the ferromagnesian constituent. In places the rocks of this group are fine-grained and aplitic in appearance, and in other localities they are exceedingly coarse and porphyritic throughout wide areas.

The relationships of the masses of granite gneiss and syenite gneiss to the older rocks into which they were intruded seem to indicate that

these masses made room for themselves in two principal ways: (1) by

thrusting aside ('1° vide + rocks; and (2) by lit par lit injection. That the batholiths ccs revm t. themselves in part, in the first manner, is indicated (1) by th dé iribut') of the older rocks in the form of belts and scalloped-shaped are. ..-rveaing between the batholiths and (2) by the manner

in which the foliation, banding, and bedding in the intruded rocks tend to parallel the batholithic margin. This parallelism is especially well developed in the easily deformed limestone member of the Grenville series. The second mode of intrusion was evidently a widespread phenomenon, for throughout the larger part of the batholithic masses of granite and syenite there are numerous included bands of garnet gneiss, quartzite, and pyroxenic gneiss ranging in width from a fraction of an inch to several hundred feet, which are penetrated by numerous transverse dykes emanating from the adjoining granite and syenite (Plate V).

Late Pre-Cambrian Intrusives.

General Statement.

The rocks occurring in the Grenville district, which have been classed as late Pre-Cambrian, are igneous intrusions which are lithologically different from the rocks of the basal complex and unlike the rocks of the basal complex have not been greatly deformed or otherwise metamorphosed. On the other hand, no rocks of similar character have been observed to intrude the Palzozoic sediments which overlie the Pre- Cambrian in the southern part of the district. It is probable, therefore, that these intrusives are not only considerably younger in age than the basal complex but also are older than the Paleozoic and are, therefore, late Pre-Cambrian in age. They include two separate types of intrusives: (1) diabase dykes and (2) a single stock-like mass of granite, quartz syenite, syenite, and quartz syenite porphyry.

Diabase.

The rocks of this class occur as numerous approximately east-west trending dykes of diabase ranging from less than a foot to several hundred feet in width, which form part of a widely extended dyke system which parallels the southern margin of the Laurentian plateau for a distance of at least 150 miles in this region. The diabase is a typical, fine-grained to coarse variety consisting of labradorite, augite, and scattered grains of ilmenite.

Granite, Quartz Syenite, Syenite, Quartz Syenite Porphyry.

Extending along the margin of the Laurentian plateau to the northeast of the town of Grenville there is an elliptical-shaped mass of rock

north- f rock

haat cilaatd Barats

approximately 8 miles in length and 5 miles in width, which has been intruded abruptly across the rocks of the basal complex, and which for the purpose of description might be designated the Grenville stock. In composition, the mass consists mainly of grey to pink, medium-grained feldspar and dark green hornblende with varying porportions of quartz so that all intermediate types between a granite and a syenite are present, although on the whole the granite is most abundant. Within the granite and syenite there are alo .umerous masses of fine-grained, dark grey, to pink aphanitic qua: t syenite perpiivry. The relationships of these masses in places is son what obscure, ut at other points they are cut across by numerous dyi.es ©! the grani!e syenite indicating that in part, at least, they are included !cc::s and older in age than the granite syenite.

Though the Grenville stock is not found in actual contact with either the diabase dykes or the Paleozoic sediments occurring in the district, it is probable, as was concluded by Sir William Logan, who studied the mass in 1853, that it is younger than the former and older than the latter; for the diabase dykes, although abundant throughout other portions of the region, have nowhere been observed to penetrate the stock, whereas dykes similar in composition to the granite syenite of the stock have not been observed to intrude the Paleozoic sediments which outcrop in close proximity to the stock on the south. It would seem probable, therefore, that the Grenville stock is very late Pre- Cambrian in age.

Pal.Ezozoic.

That portion of the Grenville district which lies adjacent to Ottawa river and south of the Laurentian escarpment is underlain by approximately flat-lying beds of Paleozoic shale, sandstone, and limestone, which protrude here and there as ledges in the stream bottoms or as low east-west trending escarpments. The formations represented by these sediments named in ascending order include the Potsdam, the Beekmantown, and the Chazy.

PLEISTOCENE. Glacial.

In common with the whole territory formerly covered by the Labradorean continental glaciers, the bedrock surface of this region is covered by an irregular mantle of glacial debris. This consists in the main of scattered boulders and irregular knobs or ridges of gravel and sand, in many parts of which deep undrained depressions occur.

donate accbimeniagioct ef, satiiesr

Sinemratine B

igen ae

Marine Clay and Sand.

Throughout all the lower portions of the Grenville district the glacial and older formations are overlain by stratified clay and sand which contain marine shells and which form extensive flats (Plate I) in the depressions within the Laurentian plateau. These marine deposits are found up to elevations of 735 feet above sea-level.! The character of these deposits varies considerably from point to point, but in the main, the clay beds predominate at the bottom and the sand at the top. In the vicinity of Ottawa river, the sand occurs in extensive areas, in places with a typical desert-like tuned surface.

1 According to elevations on Hawkesbury sheet published by the Department of Militia and Defence.

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Chapter Iii.

Magnesite Deposits. Distribution And Geological Relationships.

The deposits of magnesite so far discovered in the Grenville district are found in four principal localities; the north end of lot 15, range IX, the south end of lot 15, range XI, and the north end of lot 18, range XI, Grenville township; and lot 13, range I, Harrington township.

At all of these points, the magnesite occurs associated with serpentine, dolomite, and other minerals in lenticular outcrops protruding through the marine clay and sand which, in this district, as everywhere in the Laurentian highlands adjoining the lower Ottawa and lower S+*. Lawrence, occupies the bottoms of the major valleys. On lot 15, range IX, Grenville township, the magnesite deposit is adjoined on the west by Grenville quartzite, and on the east at a distance of about 400 feet, outcrops of pyroxenic syenite belonging to the Buckingham series occur. On lot t5, range XI, Grenville township, the conditions are very similar to those on lot 15, range IX, Grenville quartzite occurring on the west and pyroxenic gnciss on the east, but between the pyroxenic gneiss and the magnesite several outcrops of metamorphic pyroxenite are present. On the Shaw property, lot 18, range XI, Grenville township, garnet gneiss belonging to the Grenville series occurs to the east of the deposit, metamorphic pyroxenite to the south, and crystalline limestone to the northwest

. On lot 13, range I, H 'ton township, the adjoining outcrops consist of pyroxenic gneiss, c: limestone, and garnet gneiss. In general, therefore, it may bes. . .t the magnesite in all of its occurrences

is found in association with the metamorphosed group of sediments, viz., crystalline limestone, garnet gneiss, and quartzite, composing the Grenville series, and that in three localities it is found in close proximity to outcrops of the pyroxenic rocks o° the Buckingham series.

General Character.

The magnesite found in the Grenville district is a glistening cream white to milk white or grey materia! irving in extensive masses associated with bands or lenses of dark green to light yellow serpentine. Serpentine also occurs disseminated in the magnesite in places and the magnesite nearly everywhere contains more or less included dolomite. Moreover, since dolomite (CaCO; MgCO;) contains 30 per cent of lime, the magnesite generally contains a certain amount of lime also, the

apes Abe ria dsb kj cde inemiaddand Tlf Frome hnaendint es

percentage present varying in proportion to the amount of dolomite which the magnesite contains. Ina few localities the dolomite included in the magnesite is more coarsely crystallized, and is whiter in colour than the surrounding material, and can be distinguished in this way, but, throughout the great mass of the deposits, magnesite and dolomite are so similar in appearance that the presence of dolomite is difficult to detect.

The intimate manner in which dolomite is disseminated through the magnesite is made evident in several ways. Where the magnesite outcrop has been exposed to atmoe;zheric agencies, dolomite, being more soluble than the magnesite, dissolves away more readily, so that the weathered surface presents an irregularly pitted appearance, the magnesite forming the prominences and the dolomite occupying the bottoms of the depressions. This feature is well exhibited in Plate VI. The presence of dolomite in the magnesite can also be detected by treating the mixture with cold concentrated hydrochloric acid, effervescence occurring where the dolomite is present. The relationship of the dolomite to the magnesite can best be observed in the material after it has been calcined in a kiln or furnace without access of air (deoxidizing atmosphere), tne dolomite assuming a white and the magnesite a pink colour as a result of this operation. A number of specimens of magnesite colle sted by the writer were sawn and calcined in the ceramic laboratory of the Mines Brinch of the Department of Mines by Mr. H. Frechette (Plates VII and VIII). It will be observed that in these specimens the dolomitic portions appear to be included in the magnesite and possess a most irregular outline.

Structure.

In highly crystalline metamorphosed rocks, such as comprise the Grenville magnesite deposits, structural features are not everywhere apparent; but, in some of the deposits, parallel planes of parting, banding, and other features are conspicuous. The outcrops in which the magnesite is found are all elongated in a direction approximately parallel to the trend of the bedding of the quartzite and garnet gneiss belonging to the Grenville series which outcrop in the vicinity of the deposits; likewise, within the deposit ihe elongation of the masses of serpentine, the strike of the planes of parting, and the banding, which characterize the magnesite, all trend in a direction parallel to the longer direction of the outcrop and the strike of the adjoining Grenville sediments.

The banded structure generally present in the magnesite arises in part from variations in the colour of the magnes'.e and in part from variations in the proportion of disseminated serpentine which it contains. The width of the successive bands is exceedingly variable ranging from less than an inch to one foot, although on the whole the wider bands are

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ises in t from ntains. g from ids are

most common. It was observed that the proportion of serpentine in the bands changed in places when followed along the strike of the bands and, that at some points, the banded magnesite passed by a gradual increase in the proportion of disseminated serpentine into solid masses of serpentine.

The most conspicuous structural feature exhibited by the magnesite deposits is their prevailing lenticular form. Along the eastern margin of the main pit on the McPhee property (lot 15, range IX, Grenville township) there is a northeasterly trending lens (sample area 97, Map 1679) of medium to coarse-grained, white dolomite, 60 feet long ind 10 feet wide; 50 feet to the south of this lens there is a parallel trending lens (sample area 114, Map 1679) of coarse grey dolomite, 100 feet long and 20 feet wide, in which pyrite and zinc blende are disseminated. Both of these lenses apparently lie on the eastern flank of a still larger lens; for, their axial planes, as well as the banding in the adjoining magnesite, dip 75 degrees towards the southeast, whereas 50 feet westward the dip of the banding and planes of parting in the magnesite are 75 degrees towards the northwest. A still more striking example of the lenticular form is that exposed in the west face of the northern pit on the same property. At the south end of this face the banding and parallel planes of parting in the magnesite have approximately an east-northeast strike and a dip gradually curving downward towards the north-northwest. At the north end of the face 80 feet farther to the north the strike is approximately east and the dip curves downward toward the south at the top of the face but reverses back to the northward at the bottom. On the face of this pit, therefore, there is apparently exhibited a cross section of the lower portion of a large distorted lens.

Deformation.

That the magnesite deposits have been intensely faulted, crumpled, and otherwise deformed is indicated by numerous slickensided surfaces, dislocations in the banding along planes of fracture, and variations in the strike and dip of the banding and planes of parting. One of the most striking evidences of deformation in the deposits was observed near the west side of the pit on No. 3 outcrop, lot 15, range XI, Grenville township. At this point there is a dyke of biotite-pyroxene syenite, 6 inches in width, which has been crumpled into a closely compressed anticline. The magnesite exposed in the southern pit on No. 2 outcrop on the same Property was also observed to be granula'ed in places—another evidence of intend. information. It is probable that the le~~'cular structure so common in the magnesite deposits is also the result ot deformation, since the banding in the magnesite adjoining the lenses everywhere conforms

to the margin of the lens. This feature is exceptionally well shown where the magnesite adjoins a crumpled lens of serpentine in sample areas Nos. 41 and 42, on the No. 1 outcrop on the Scottish Canadian property (Map 1679).

Mineralogy.

The minerals observed to be present in the magnesite deposits, named in the order of their abundance, are as follows: magnesite, serpentine, dolomite, diopside, phlogopite, quartz, talc, pyrite, sphalerite, magnetite, and graphite. The character and mode of occurrence of each of these are briefly described in the following sections.

Magnesite (MgCOs: magnesium 47-6, carbon dioxide 52-4 per cent). Magnesite or magnesium carbonate as found in the Grenville district isa glistening cream white, snow white, milk white, or grey, fine-grained material having a specific gravity of 3-00 and a hardness of 3-5. The general character and mode of occurrence of the mineral have been described in previous sections.

Serpentine (3MgC. 2Si02. 2H.0: magnesia 43, silica 44-1, water 12-9 per cent). The serpentine found in the magnesite deposits occurs partly in masses or bands of various sizes up to several hundred feet in length and 50 feet inwidth and partly as round grainsdisseminated through the magnesite or magnesite-dolomite. It may be dark green or almost black, emerald green, blue green, yellow green, yellowish brown or wax yellow in colour, is exceedingly fine-grained, and possesses a waxy lustre. In the larger masses it commonly contains considerable finely disseminated amber brown mica.

Dolomite (CaCO;MgCOs: magnesia 21-7, lime 30-4, carbon dioxide 47-9 per cent). The dolomite associated with the Grenville magnesite occurs partly as small grains or aggregates of grains intimately disseminated through the magnesite, and partly as large irregular masses or senses included in the magnesite. Corresponding to these two modes of occurrence there is a marked difference in the physical character of the mineral: for, while the disseminated dolomite is generally fine-grained and glistening and similar in appearance to the magnesite, the large masses are coarsely crystallized with a well developed rhombohedral cleavage.

Diopside lime 25-9, magnesia 18-5, silica 55-6 per cent). Extensive masses of the variety of pyroxene known as diopside are included in the magnesite deposits in a number of localities, especially near the contact of the magnesite with the Grenville quartzite which adjoins the deposits in places. The mineral as found in these masses is not strikingly different in appearance from the magnesite. It can be distinguished, however, by its somewhat greater specific gravity, rectangular cleavage, vitreous lustre, light pale green colour, and subtranslucency.

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Phlogopite (composition variable approximately, silica 40, alumina 17, magnesia 27, potash 11, fluorine 2, water 3 per cent). Phlogopite, or amber mica, as far as was observed, is confined entirely to the large masses of serpentine in which it occurs in the form of finely disseminated flakes. It is a typical light amber variety quite similar in every respect to the phlogopite found in association with the contact pyroxenite in other parts of the same region.

Quartz (SiO.). Masses of quartz were observed to be present in the magnesite deposits, at the north end of No. 1 outcrop on lot 15, range XI, Grenville; at the southwest end of the main pit on the McPhee property; and on the northwest margin of the pit opened by Messrs. Fitzsimmons and Boshart at the south end of lot 16, range IX, in Grenville township. It is possible that aii of these occurrences are merely beds or masses of Grenville quartzite, since extensive outcrops of this rock adjoin the deposits.

Talc (3MgO.4SiO2.H20: magnesia 31-7, silica 63-5, water 4-8 per cent). The talc found in association with the magnesite deposits is char .cterized by the waxy lustre and light greenish grey colour which usually characterize that mineral. It occurs chiefly with serpentine, filling fractures in the diopside masses.

Pyrite (FeS,: iron 46-6, sulphur 53-4 per cent). Pyrite or iron pyrites occurs very commonly in the magnesite deposits in the form of irregular grains or cubes disseminated through the large serpentine masses and the dolomitic portions of the deposits. It is not generally present in the magnesite itself, nor in those portions of the deposits in which the proportion of dolomite is small.

Sphalerite (ZnS: zinc 67, sulphur 33 per cent). Sphalerite or zinc blende was observed at a few points in the magnesite deposits associated with the disseminated pyrite in the form of irregular, brownish-black grains. It has been found in abundance at only one point, namely, along the southeastern margin of the main pit on the McPhee property (lot 15, range IX, Grenville township). There, a iens of coarse grey dolomite, 100 feet long and 20 feet wide, occurs in which sphalerite intimately intergrown with pyrite is disseminated.

Magnetite (FeO: iron 72-4, oxygen 27-6 per cent). The presence of magnetite, magnetic iron oxide, was noted at a few points in the dolomitic portions of the magnesite deposits. It occurs in the form of octahedral grains up to one-half inch in diameter disseminated through the masses of coarsely crystallized dolomite.

Graphite (Carbon). Graphite is not commonly present in the magnesite deposits, but was observed to be finely disseminated through a zone of serpentinous dolomive-magnesite in the bottom of the main pit on the McPhee property.

Origin.

The deposits of magnesite found throughout the world are all regarded as having originated in one or other of three ways. The Grecian magnesite deposits, most of the magnesite of California, and many other deposits found in various parts of the world, are believed to have been formed by the decomposition of serpentine, the serpentine in its turn being a decomposition product derived from olivine-pyroxene rocks (peridotites). The transformation of the serpentine is presumed to take place according to the following formula:

3MgO.2SiO, .2H,0+3CO, 3MgCO;+2Si0,+2H:0.

Magnesite deposits occurring near Bissel in California and in the valley of Muddy river near St. Thomas in Clark county, Nevada,! on the other hand, are said to be of sedimentary origin. The Austria-Hungarian deposits were also formerly thought to be of sedimentary origin, but are now generally regarded as the product resulting from the replacement of limestone by magnesian bearing solutions. A classification of the known deposits of magnesite according to genesis would, therefore, include:

(1) Deposits formed by the decomposition of serpentine. (2) Sedimentary deposits. (3) Deposits formed by replacement of limestone.

The study of the character and relationships of the Grenville magnesite deposits seems to indicate that these deposits belong to class 3 and are thus similar in origin to the Austria-Hungarian magnesite.

Decomposition of Serpentine. Since the Grenville magnesite deposits contain considerable serpentine, it might be presumed that the magnesite is an alteration product derived from the serpentine, and thus belongs genetically to the deposits of class 1. Magnesite deposits derived from serpentine, however, are generally characterized by the following featur: 3: (1) The serpentine is itself an alteration product derived from roc!.s of the peridotite family, (2) the magnesite occurs as veins or veinlets or irregular masses in the serpentine, and (3) the magnesite is usually traversed by veins of chalcedony and quartz. In the case of the Grenville magnesite deposits, on the other hand, there is no evidence anywhere in the district that peridotite was ever present in association with magnesite deposits, while there is much positive evidence indicating that the serpentine has originated by replacement of limestone in the manner described in section 3 below; the magnesite does not occur as veins traversing the serpentine, and except for a few isolated masses a few feet in diameter, quartz is entirely absent from the deposits. It is improbable

1 Min. and Eng. World, vol. 44, 1916, p. 482. Min. and Sc. Press, vol. 114, 1917, p. 238.

are all 3. The a, and eved to ntine in yroxene resumed

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of the erefore,

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ee isd beh siaa east lbs insiihsg pa nada Basin nh anhalal al eehiielenctiasitele

therefore, that the magnesite masses composing the Grenville deposits are directly related genetically to the serpentine with which they are associated.

Sedimentary Deposition. The rocks adjoining the magnesite deposits, in so far as they are exposed, consist in the main of quartzite, garnet gneiss, and crystalline limestone belonging to the Grenville series. The association of the magnesite with these metamorphosed sediments might, therefore, indicate that the deposits were of sedimentary origin; but the Grenville series originally consisted of interstratified beds of shale, sandstone, and limestone, sediments differing in no respect from well sorted marine deposits laid down during more recent geological periods; and, it is generally assumed on the basis of both geological and chemical evidence that magnesium carbonate would not be deposited in large masses under such .:onditions.!

However it has been suggested by Daly? that in Pre-Cambrian time conditions of marine deposition were strikingly different from those prevailing at a later stage in geological history, the ocean eing nearly lifeless. But the very existence of the Grenville series, which includes a large proportion of limestone, seems to disprove this hypothesis. The Grenville series had originally a minimum areal extent of ai 'east 150,000 square miles and whether the thickness of nearly 18 miles assigned to the series in eastern Ontario by Adams and Barlow® be an excessive estimate or not, the wide extent of the series and the fact that the floor upon which the series was laid down has nowhere been observed seem to indicate that the thickness is at least many thousand feet. Furthermore, the Grenville series throughout the greater part of its extent has been intimately intruded by pyroxene gabbro, pyroxene diorite, anorthosite, and related rocks, by which the limestone member has been purely or completely metamorphosed to diopside, serpentine, phlogopite, and many other magnesian silicates; and the larger part of the analyses of Grenville limestone, contained in geological publications, has been made from specimens collected without regard to these geological relationships or the possibility that the magnesian content of the rock had been increased by contact metamorphism. Yet despite this random selection of material many of the analyses of Grenville limestone show the magnesia content to be less than 2 or 3 per cent.' It must be concluded, therefore,

1 Van Hise, C. R., U.S.G.S. Mon. 47, 1904, pp. 802, 808. Clarke, F. W., "Data of Geochemistry," U.S.G.S., Bull. 491, 1911, pp. 534-545. Johnstoa, J., The solubility product constants of calcium and magnesium carbonate,"' Jour. Am. Chem. Soc., vol. 37, 1915, p. 2001. Redlich, Karl A., Die Bildung des Magnesits und sein naturliches. VYorkommen, Fortschritte der Min., Krist. und Petr. vol. 4, 1914, pp. 9-42. 2 Bull. Geol. Soc. Am., vol. 20, 1909, pp. 153-170, Am. Jour. Sc., vol. 23, 1907, p. 93. Geol. Surv., Can., Mem. 6, 1910, p. 33. Miller, W. G. and Knight, C. W., "The Pre-Cambrian geology of southeastern Ontario," Bur. o Mines, Ont., 1914., pp. 21, 77, 86. Frechette, H., Mines Branch, Dept. of Mines, Can., Sum. Rept., 1914, pp. 36-37.

a

that in so far as the deposition of magnesium carbonate is concerned, conditions of deposition in early Pre-Cambrian time in the Grenville district were probably not essentially different from those in more recent geological epochs, and, if this were the case, it is very improbable that the magnesite deposits are of sedimentary origin.

Replacement of Limesione. Among the more important data that might be cited in favour of the hypothesis that the magnesite contained in the Grenville magnesite deposits has been deposited by replacement of limestone are the following:

(1) In the section of the memoir in which the structure of the magnesite deposits was described, pages 26 and 27, it was pointed out that the magnesite was banded in places, the difference in the bands being partly due te difference in colour and partly to variations in the proportion of disseminated serpentine in different bands; but, the Grenville limestone commonly exhibits a banding strikingly similar to this, the only difference being that in the case of the limestone the disseminated grains in many places consist of diopside or partly serpentinized diopside as well as serpentine (Plate IX.') The similarity of this phenomena in both the limestone and magnesite seems to indicate that there is, in some way, a close genetic connexion between the magnesite and the Grenville limestone.

(2) In numerous localities not only in the Grenville district but throughout a considerable part of the region in which the Grenville series is found, the :,stalline limestone member of the series contains nodular masses cf 'cry zntine, or diopside partly altered to serpentine. which in some cases are several hundred feet in diameter. The presence of such masses in the limestone can scarcely be explained by any other hypothesis than that they have been formed from the limestone by silication.

(3) In many localities throughout the region in which the Grenville series is found, there are also extensive masses of rock generally known as "'pyroxenite" with which the mica and apatite deposits of eastern Ontario and Quebec are associated. These masses are composed of diopside, scapolite, phlogopite, apatite, feldspar, quartz, calcite, tremolite, actinolite, serpentine, tourmaline, chabazite, stilbite, zircon, vesuvianite, and other minerals of similar character. It is believed from the association of these masses vith limestone, from the abundance of lime silicate and pegmatitic minerals which they contain, and, from the high lime content of the deposits as a whole, that they have been formed from the limestone through the agency of pegmatitic magnesia-rich solutions."

1 The photograph reproduced as Plate IX was taken at the town of Buckingham, situated SO miles to the west of the Grenville district, but exhibits a feature which can be observed almost everywhere in the Grenville limestone.

2 Trans. Can, Min. Inst., vol. 19, 1916, pp. 349-370.

Geol. Surv., Can., Sum. Rept., 1915, pp. 156-168.

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(4) In places masses of dolomite occur associated wit' + serpentine contained in the limestone, and in a few localities the dolomite can be seen to be distributed irregularly along fractures traversing the limestone.

(5) The rocks of the Grenville series have been intruded almost everywhere by bosses and thin Hit par lit injections consisting of pyroxene gabbro, pyroxene diorite, pyroxene syenite, diorite pegmatite, and syenite-pegmatite, and it would, therefore, seem probable that the solutions by which the limestone was transformed into diopside and other minerals emanated from these intrusives.

(6) The association of diopside and phlogopite with the Grenville magnesite deposits indicates that there is a genetic relationship between the magnesite deposits, the masses of diopside and serpentine found in the limestone of the Grenville series, and the metamorphic ''pyroxenite," and that they have all been formed in some way by the transformation or replacement of limestone.

On the whole, therefore, there is considerable positive evidence in support of the hypothesis that the magnesite deposits have been formed by the silication and replacement of Grenville crystalline limestone; and, on this assumption it is possible, from the character and relationships of the deposits, to outline approximately the manner in which this transformation took place.

The probable order of events by which the magnesite deposits of the Grenville district were formed was as follows: (1) silication of limestone to diopside and the formation of phlogopite in places, (2) formation of serpentine in places, (3) replacement of limestone by dolomite, (4) replacement of dolomite by magnesite, and (5) the alteration of diopside to serpentine.

As regards the orizin of the serpentine associated with the magnesite deposits, it is difficult to determine whether this mineral replaced the lime: directly or indirectly through the alteration of diopside, and both vu, ...ese possibilities have, therefore, been included as stages 2 and 5 in the formation of the magnesite deposits. In the case of the inclusions of serpentine, which occur associated with the Grenville limestone, there is direct evidence to indicate that the serpentine has been derived from diopside, but this transformation presumably takes place according to the following equation:

3CaMg + 3CO, + 2H:O=3MgO, 2SiOz, 2H,0 + 4Si0, + 3CaCO;

and should, therefore, be accompanied by the setting free of considerable quantities of quartz, whereas as far as was observed quartz is not present in association with the serpentine of the magnesite deposits.

From the occurrence of the dolomite as scattered inclusions in the magnesite, it would appear that the replacement of the limestone by

magnesite was effected in a manner somewhat similar to that originally suggested by Redlich for the magnesite deposits of Austria-Hungary, namely, by two chemical reactions, dolomite being formed in the first reaction and the magnesite in the second.' The second reaction was not carried to completion, however, throughout the Grenville magnesite deposits and in consequence included remnants of dolomite remain disseminated through the magnesite. The reactions according to Redlich were as follows:

(1) CaCOs + MgCOs MgCaCO; + CaCO,. (2) MgCaCOs + MgCOs 2MgCOs + CaCO?

Determination Of Lime Content Of Magnesite And Magnesite-D Jlomite.

Physical Characters. In mining the magnesite from the Grenville deposits it is customary to remove the dolomitic material as far as possible from the ore by cobbing; and, since in this operation the presence of the dolomite is determined only by such differences in appearance as distinguish magnesite from dolomite, the relationship of the lime content of the magnesite-dolomite to its physical character is of practical importance. From the determinations of the percentage of lime contained in the samples described in Tables I to VIII, the following general conclusions are inferred.

Cream-white, medium to fine-grained, glistening magnesite usually contains less than 7 per cent CaO.

Snow-white, medium or fine-grained glistening magnesite usually contains less than 11 per cent CaO.

Milk-white, inedium or fine-grained glistening magnesite usually contains less than 12 per cent CaO.

Grey magnesite is generally more highly dolomitic than either cream-white, snow-white, or milk-white materi:.. but there are a few striking exceptions to this rule.

Dull white material is dolomite and contains approximately 30 per cent CaO.

Coarsely crystalline material (that is, material exhibiting cleavage faces generally greater than one-fourth inch in diameter) is usually dolomite and contains approximately 30 per cent CaO.

Action of Concentrated H ydrochloric Acid. Since dolomite is much more soluble in hydrochloric acid than magnesite, the percentage of dolomite contained in the Grenville magnesite can also be approximately determined from the behaviour of the material when treated with cold concen-

1 Techermak's Mineralogishe Mitt. 1907, p. 499.

Redlich has since modified his original suggestion with regard to the mode of origin of the Austro- Hungarian magnesite and now regards the replacement of limestone by magnesite as the first operation, and the formation of dolomite as the second.

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trated hydrochloric acid. In practice it was found that the acid had usually no apparent effect on fine to medium-grained magnesite-dolomite in which less than 7 per cent of lime was present, that a feeble efivrvescence in widely separated spots occurred on magnesite-dolomite containing less than 12 per cent CaO, and that more than a feeble effervescence in widely separated spots indicated that the percentage of lime present was greater than 12 per cent. It was also found, however, that coarsely crystalline material did not effervesce as readily as fine-grained magnesite dolomite.

Calcination. The percentage of CaO contained in the magnesitedolomite can also be approximately determined by means of the difference in colour of the magnesite and dolomite after the material has been calcined. Thus in the case of the cut face of the specimen of magnesitedolomite shown in Plate VII B, the total area of the inclusions of dolomite amounts to approximately 8 per cent of the area of the whole face, and since dolomite contains approximately 30 per cent of CaO, the specimen contains approximately 24 per cent CaO. This determination is probably within one-half per cent of the CaO content actually present, for the specimen shown in Plate VII B was selected as the best grade of material represented in area No. 117 on the McPhee property (lot 15, range IX, Grenville township), the lime content of which was determined by chemical analysis to be 3-93 per cent (Table VII, p. 55).

Explanation Of Tables And Outcrop Maps.

For the purpose of determining the variation in quality, the extent, and the relationships of the magnesite and magnesite-dolomite contained in the Grenville deposits, the outcrop maps shown in Map 1679 were prepared by means of the plane-table, alidade, and chain. In preparing these maps, those parts of the outcrops underlain by magnesite and magnesite-dolomite were subdivided into numbered areas, material of the same physical character and quality being included as far as possible in the same area. From each of these areas average samples were procured by collecting chips from each square foot of surface. Since in practice, however, it is customary to remove serpentine and dolomitic material from the ore as far as possible by cobbing, cobbable material of this cass was not included in the samples. The physical character and the lime content, etc., of the samples collected from the various areas are indicated in Tables I to IV, VI, and VII, accompanying the descriptions of the various properties.

In these tables, colour, lustre, grain, percentage of material cobbed, and composition of material cobbed are indicated. Under the heading grain, the magnesite is classified as fine, medium, or coarse, according

aasuipamtetias iiaeni ta Tena err

as its grains are less than of an inch, $ to 4 of an inch, or greater than 3 of an inch in diameter, respectively.

In Tables V and VIII a summarized statement of the number of feet of magnesite, magnesite-dolomite, and serpentine contained in diamond drill cores obtained in lot 15, range XI, and lot 15, range IX, Grenville township, is included.

r of

in IX,

a BS A mr

Chapter Iv.

Descriptions Of Properties. General Statement.

In the following chapter the deposits of magnesite and magnesitedolomite so far discovered in the Grenville district are described and the tonnage of magnesite and magnesite-dolomite known to be present in each deposit estimated. A list of the lots on which the various deposits occur and of the owners of these lots is included in the following table:

List of Properties.

Lot Range Township Owner 13 1 Harrington. International Magnesite Co., Ltd. 18 11 Grenville. North American Maghesite Co., Ltd. 15 11 Scottish Canadian Magnesite Co., Ltd. ; North American Magnesite Co., Ltd. 1 16 9 Fitzsimmons and Boshart. 11 8,N . Campbell. 12 8, N Fitzsimmons and Boshart. 11 eo is 12 8,S C . 9 11 Augmentation of Grenville. 21 1 Harrington. 717 10 Grenville.

Lot 13, Range I, Harrington Township, Dobbie Mine.

The Dobbie magnesite mine, the property of the International Magnesite Company, lies near the north end of lot 13, range I, Harrington township, and near the eastern margin of the broad flat which adjoins Rouge river in the southwestern part of Harrington township.

The outcrop in which the magnesite is found has an areal extent of approximately 300 by 200 feet, but at the time the deposit was visited by the writer in January 1917, only an area 25 by 50 feet, where mining operations had been commenced, was visible through the heavy cover of snow. The part of the deposit being mined averaged 7-5 per cent CaO.' It consisted in part of glistening white magnesite and, in part, of medium to coarse-grained, grey material containing disseminated grains of dark green serpentine.

1 According to analyses by J. T. Donald and Co. of Montreal.

A series of samples from an area about 100 feet square on the surface of the outcrop was collected and analysed by J. T. Donald and! Company of Montreal and was found to carry the following lime content:

Sample No. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Per cent CaO 6:58 7-72 10-45 7-26 7-72 11-19 10-68 7-94 4-77 10-68 18-77 Average omitting No. 11 +sssee00- 8-50

An average sample from a shipment of magnesite from the property

was also found to have the following composition

Gig ere Sarre ete ba Be IE Ea atas Calne Re cineee Iron oxide and alumina. .

Magnesia te Loss on ignition cceceeeescessecscccnees

The quality and extent of the magnesite already known to be present on this property seem to indicate that the quantity of ore actually present may be extensive, but much development work is required before this can be positively determined. All that can be stated at present with regard to the deposits is that, on the basis of certain assumptions inferred from the study of the magnesite deposits as a whole, it is calculated that at least 25,000 tons of magnesite ore is present. The data on which this estimate is based are as follows:

Known horizontal extent of deposit, 10,000 square feet.

Assumed depth, 50 feet.

Assumed proportions of magnesite present in deposit, 60 per cent.

Number of cubic feet of magnesite in one ton, 12

Accompanying the magnesite there is also probably present at least 8,000 tons of magnesite-dolomite.

A number of camp buildings have been erected on the property.

Lot 18, Range Xi, Grenville Township, Shaw Mine.

This property is situated at a distance of approximately 15 miles from the Canadian Pacific railway, and, on this account, is operated only in the winter, when the cost of transportation to the railway by sleigh is $2.50 per ton as compared with a cost of $4.5C in the summer. At the time the outcrop was examined by the writer in July 1916, the surface of the magnesite was so covered by broken rock, left at the close of the previous winter's operation, that maenesite in place could not be seen except along the southern face of the pit and in a low ledge projecting through the rock debris near the north end of the deposit.

The rock outcrop in which the magnesite is found originally formed a low northeasterly trending ridge, but it has been excavated down to the same elevation as the surrounding flat except at its south end where a face from 10 to 20 feet high remains, out of which an extension of the

1 According to analyses by J. T. Donald and Co., of Montreal.

sent ually efore with erred that . this

least

miles 1 only sleigh . At e surose of ot be ecting

ormed wn to here a of the

main pit from 15 to 20 feet wide has been excavated southward for a distance of 50 feet. A diagrammatic section across the face of this extension is shown in Figure 2. It is stated by Mr. Broadbent, who examined the deposit in 1900, that the magnesite is intersected by a small dyke of porphyrite.t This dyke was not observed in place by the writer, but a number of fragments of black aphanitic diabase porphyry were observed on the dumps which were probably derived from the intrusion referred to by Mr. Broadbent.

Sov Rock debris Serpentine

Dolomite

Samp/* areas

Figure 2. Diagrammatic section across south face of pit in magnesite deposit, lot 18, range XI, Grenville township.

Descriptions of the physical characters and the chemical analyses of samples from the magnesite deposit on the Shaw property are included in Table I. Samples Nos. 1 to 17 were collected from areas on the south face of the southern extension of the main pit as shown in Figure 2. Sample 18 was taken from a mass of magnesite exposed near the north end of the eastern face of the southern extension of the main pit, and samples 19 to 22 were taken from the projecting ledge of magnesite exposed near the north end of the deposit. Sample 23 represents the average of a small pile of ore remaining in the middle of the pit. The remaining samples (Nos. 24-35) were collected from the surface of the outcrop by Mr. Broadbent in 1900 and were described by him in the report of the section of chemistry of the Geological Survey for that year.

1 Geol. Surv., Can., Ann. Rept. vol. XIII, 1900, pt. R, p. 15.

Since the Shaw property was examined by the writer a single diamond drill hole has been drilled on the property to a depth of 64 feet with the following result:

Number of feet Number of feet Number of feet containing less than containing more of serpentine. 13 per cent CaO than 13 per cent CaO 234 23 174

At a depth of 35 feet a marked increase in the per cent of lime occurred in this core, but this may possibly be due to the fact that a lens of dolomitic material was encountered at this point.

Owing to the poorly exposed condition of the magnesite deposits at the time it was examined, and the absence, except for the single drilling record, of information with regard to the depth to which the deposit extends, the data necessary for even an approximate estimate of the total tonnage of magnesite present on the Shaw property are not available; but, on the basis of certain minimum assumptions, an estimate of the approximate number of tons of magnesite in sight can be obtained. The data on which such an estimate can be based are the following:

Approximate superficial extent of deposit, 15,000 square feet.

Assumed average depth to which deposit extends, 25 feet.

Proportion of magnesite averaging 10 per cent CaO in deposit, 50 per cent. Proportion of magnesite averaging 16 per cent CaO in deposit, 20 per cent. Proportion of serpentine in deposit, 30 per cent.

From the preceding information it can be calculated that there is present in the deposit approximately 15,000 tons of magnesite averaging 10 per cent lime and 6,000 tons of material averaging 16 per cent lime.

It is, of course, possible that the deposit extends to a greater depth than 25 feet; but, in view of the results obtained from the single hole drilled, a greater depth could not be safely assumed in making a definite estimate of the tonnage. Similarly, it is possible that the superficial extent of the deposit may eventually prove to be greater than 15,000 square feet, but further development work is required before this can be determined. The percentages of serpentine and magnesite present in the deposit were determined partly from the information contained in Table I and partly from the known general character of the magnesite deposits of the district as a whole.

A two-story camp building having accommodation for about twenty men has been erected on the property.

diafeet

are is aging lime. lepth hole finite rficial 5,000 s can ont in ed in nesite

about

Table I. Physical Character and Chemical Composition of rela of Magnesite from Out North Half of Lot 18, Range X1, Grenville Township. : a ee ere

Equivalent to Silica and No. Colour Lustre Grain CaO , insoluble matter.

1 |snow-white 8-77 40:28 15-60! 84-18 0-50 2 |snow-white 6-83 40:48 12-20] 84-60 2-90 3 |snow-white 7-96 40-66 14-21 84-98 0-88 4 |white 14:90 34:38 26-60 71-86 2:16 5 |white 11-87 31-82 21-20 66-50 22-00 6 |blue-grey 11-96 38-02 21-35 79-26 0-10 7 |snow-whit 11-25 37-78 20-40 78-96 1-50 8 |snow-white 12-18 35:70 21-78 74-61 6-10 9 |white 8-33 39-40 14-87 82-34 2-32 10 |white 14-31 35-74! 25-58| 74-70! 0-50 11 |white 0-87 37-02 1-55 77:38 26-40 12 |white 11-17 7-36 19-94 78-08 2-20 13 |white ]glistening medium 9-80 35-08 17-50 73-32 28-04 14 grey JGull /fime 15-86 33-08 28-32 69-14 2-00 15 |white 9-95 37-94 17-77 79-30 2-38 16 white 10-48 36:46 18-71 76-20 3-30 17 |snow-white ' iahenigeys a san 10-44 37-60 18-64 78-58 0-90 18 |cream-white Berean: 8-58 39-56 15-32 82-64 0-80 JO pinks cass ccs Ws ise'sp aes 11-76 36-10 21-00 75-44 2-24 ening 21 snow-white ull 29-60 30-32] 62-20 11-40 22 \snow-white 'listenin: 40-54 11-52 84-72 2-36 23 |Average sample fr.ora ore pi 38-02 18-14 79-46 1-84 24 |blue-white j 37-35 16-07 77-62

25 |blue-white 5 fine 33-45 18-89 74-68 26 imilbowhite, 0.03065) oc sscccess : 38-17 15-57 78-08 28 |blue-white ] 36-22 16-00 76-09 29 grey to reddish...| 36-61 13-14 76-97 white 30 jgreyish-white ] fine : 23-66 30-14 49-71 31 |greyish-white bee eae 5593 19-71 75-69 reddish-white S23 yrepewhdte sais chia cise vacaes ' 39-36 12-36 82-72 33 |blue-white ] 0000: medium 6: 40-46 10-80 85-00 translucent 34 |snow-white ) medium a pei 45-36 ] 95-50 subtranslucent centage 35 [Average sample from surface of| outcrop.. 9-12 36-68 16-28 77-07

Analyses 1-23 by Mr. H. A. Leverin of the Mines Branch, Department of Mines, Ottawa. Analyses 24-34 by Mr. F. G. Wait, Geol. Surv., Can., Ann. Rep., 1900, pt. R, pp. 14-17.

Lot 15, Range Xi, Grenville Township.

On this lot a series of three exposures of magnesite, magnesitedolomite, and serpentine, occur along the eastern margin of the flat which extends southward from Grenville lake at the south end of the lot. These outcrops numbered from south to north are known as Nos. I, II, and III respectively. The descriptions of the physical character and lime content of samples from the surface of these outcrops have been tabulated in Tables II to IV, while the proportions of magnesite, magnesite-dolomite, and serpentine contained in diamond drill cores obtained in drilling operations on the property by the Harbison-Walker Refractories Company of Pittsburg are summarized in Table V.

jain

pee aia pas aad He viattaciiaet Pett

Outcrop No. I.

Magnesite of No. 1 quality is known to occur along the southern and southwestern margin of this outcrop, and in the vicinity of diamond drill hole No. 15. A summation of the proportions of magnesite, magnesite-dolomite, and serpentine exposed in the southwestern portion of the deposit (outcrop No. I, and table IT) is as follows:

Per cent Magnesite 0eee reece eeees 6 Magnesite-dolomite :.++555 8 Serpentine :seee reece eeeees 30

A similar summation for the diamond drill cores obtained in this area and from hole No. 15 (see table V) is as follows:

Per cent. Magnesite cee renee ere eeees 66 Magnesite-dolomite 6++++00> 12 Serpentine eeee reer reer e eens 22

It can be safely assumed, therefore, that in these portions of the outcrop the proportion of magnesite containing less than 12 per cent lime is at least 60 per cent. From the examination of the various deposits in the district it is inferred that, as a rule, the quality of the material obtained from a drill hole will be maintained horizontally for a distance of at least one-fourth the depth of the hole in either direction along the strike of the deposit and one-eighth the depth of the hole in either direction at right angles to the strike.

On the basis of these assumptions the following data are available from which the number of tons of magnesite in sight in No. I outcrop can be estimated:

Superficial area of deposits adjacent to diamond drill holes Nos. 11, 8, and 10, 4,800 square feet.

Proved depth to which deposit descends in area adjacent to drill holes Nos. 11, 8, and 10, 50 feet.

Total horizontal extent of deposits adjacent to diamond drill holes Nos. 12, 13, 20, and 15, 20,000 square feet.

Proved average depth to which deposit descends in the vicinity of diamond drill holes, Nos. 12, 13, 20, and 15, 180 feet.

Proportion of magnesite containing less than 12 per cent CaO in deposit, 60 per cent.

Proportion of magnesite-dolomite in deposit, 10 per cent.

Number of cubic feet of magnesite in 1 ton, 12

The tonnage of material present in the deposit is, therefore, as follows:

Magnesite. Magnesitedolomite Adjacent to drill holes Nos. 11, 8, and 10... 12,000 tons 2,000 tons. Deposits in the vicinity of holes Nos. 12, 13, 20, and 15... 5.22.0 aieerseeee 180,000 tons 30,000 tons

Si 7 Oe eran ree hoor a eten ees 192,000 tons 32,000 tons.

In those parts of No. I outcrop not included in the above estimate

hern there is exposed approximately 7,000 square feet of rock surface composed ond 4 as follows: : Magnesite, 8 gne- 4 Marsuhedelemhe averaging 16 t CaO, 62 the q Serpentine, diopside, and ' and quarts, Son cm. 4 Most of these areas are scattered over the surface of the outcrop, and

it is only in the vicinity of diamond drill hole No. 18 that a mass of magnesite-dolomite of workable dimensions is known to occur. At this point approximately 5,000 tons of magnesite-dolomite are present.

this Teble 11. Physicel Character ond Lime Content of Samples of Magnesite from Outcrop No. 1, Lot 18, Range X1., Township. EF Percent cent Per cent of + No. Colour Lustre Grain of cob. Material cobbed a "CaO CaO in ma- ® terial cobbed 75:00? 15-00 i the 3 22-008 cent 4 -001 rious s 18-008 6 9-00! ' the 7 7 |snow-white to grey... 10-00! 24-00 jai a 4 8 cream white. 7-00! ction 9 |cream white. ses 6-968 310 white to grey gre: ae 13-00! 18-00 hole z dolomite 1 cream white to snow-coarse white dolo- 12-00! 26-00 white mite lable 3 grey to white.. white to crop ey-whiie 28-00 nd 10, 11, 8, 4 ite oe 13, 20, i milk-white to grey . while to grey id drill grey-white white... or cent. .S are oa re, as 3 sneer welee to milk- a t grey-white snow-white. . re- 4 — e oS white. . Son ons. lenow-white ad milk-fine dull white and grey 9-748 hite dolomite Pare : ons ees nteatinte tie Steer ni ethic SF a esceae 8-00! ons.

+ z et ba

MDaRa atest Tact co

oa

Table 11.—Continued.

er Ne

Percent| Per cent of of CaO CaO in material cobbed!

ges seessrsseseses

green gorpentis z rely -- white dolomite

a o>.

1 Fstimated. 2 Determined by Miss D. M. Stewart, Mines Branch, Department of Mines.

Outcrop No. II.

Magnesite and magnesite-dolomite are known to occur in this outcrop at four points. (See map 1679 and Tables III and V). On the basis of assumptions similar to those made in the case of No. I outcrop, the number of tons of magnesite and magnesite-dolomite in sight in each of these localities is estimated as follows:

Locality Tons of Tons of magnesitemagnesite. dolomite. Adjacent to diamond drill hole No. 23 9,000 1,500 Adjacent to diamond drill holes, Nos. 22, 24, Pe 1 ok ogre paren ait CU ge SCC 27,500 17,000 Adjacent to diamond drill holes Nos. 27 and 28 2,500 200

Gt DON IR Sey Cpe eoetEe 39,000 18,700

Tobdle 111. Physical Character and Lime Content of Samples of Magnesite from Outcrop No. 11, Lot 15, Range xl, Grenville Township.

Percent; Per cent of Colour Material cobbed CaO CaO in material cobbed ZEEE COCOCG SOCUngoananeG Santini Mm. lll Gomory ee nnn rs 20:00! snow-white to milk-white stistent winesee 20 |serpentine 10-00! white to grey ++. Siatenion 'and dull biine vets nil {dull white serpentin- 13-008 ous material snow-white...e. sce cceee iglistening fine DR bo sccpistrnecekune se 11-001 22.00 snow-white to grey glistening Rc savas ON Poccwssccesed ++. 10-00 snow-white to grey |glistening BRO... e es 20 {serpentine 12:00 snow-white seeeseree listening Peeaeiee fine granu- 2 magnesite dol-} 14-708 15:00 snow-white -|glistening fine average sample from pile 'of ore excavated 7 om pit at 9 anow-white 6e.-++ eli: ing.. snow-white +..+++- glistening ' eee ee eee Pe j snow-white +|glistening So |erey jnaanesite-dot- 11-00! 14:00 om FS snow-white |glistening. .. 2 '|grey tees 13-499 14-00 ' omite : snow-white.. - glistening. 10 oo gehen a 9-001 13-00 snow-white.. glistening 20 Ba magnesite-| 12-00! 15-00 lolomite snow-white 655 glistening .|fin $ |dull grey dolomite. 11-00! 20-00 snow-white +.- glistening a Sorcerer ret ree ' snow-white glistening to Sa Seon ee ocr oo] 11-429 shining grey . - glistening RE Piatersscucesecvs 12-00 medium grey and pink etistening to dullifine to 25 coarse grey magnes-| 10-00! 15-00 and shining medium ite-dolomite janow-white glistening DROE aces 25 grey masoeice-dol- 9-18? 14-00 omite snow-white glistening 2d Se ae ee 10-00! snow-white |glistening... 75 coarse grey magnet-| 9-00! 15-00 ite-dolomite grey and snow-white. .. . |glistening 50 Ain esite- 10-00! 15-00 jolomite grey , [Shining and glist-/medium to 25 magnesite- 13-00! 16-00 ening fine dolomite snow-white to milk-white/shining and glist-|medium... 40 {grey magnesite- 9-00! 14-00 ening dolomite a DN RAR eee Se heer medium to ice cacrree tones she 13-00! coarse snow-white glistening ce Seer 8 Serer 10-00! snow-white glistening Fe ee 2 {coarsely crystalline 9-782 15-00 magnesite-dolosnow-white glistening nil snow-white -{glistening nil snow-white iglistening 5 snow-white glistening nil we snow-white glistening 10 —|grey magnesite- 10-00! 14-00 dolomite isnow-white glistening. WE lice ones eas kane he 7-00! snow-white glistening Ge. os 3 ct a (eer ae See ek granulated snow-white glistening /fine $0 =dull white dolomite 7-00! 24-00 cream-white |glistening Ls area 40s grey Ha ea 9-00! 15-00 dolomite cream-white and grey |glistening |fine 50 —_|grey magnesite- 9-00! 15-00 dolomite . white and grey glistening \fine 25 13-00! 14-00 dolomite cream-white and grey |glistening /fine 50 ae ag 8-68 13-00 lolomite cren.m-white and grey |glistening /fime 5 erey magnesite 9-00! 13-00 dolomite snow-white glistening Sperirers 5 CSems srpeies 10-00! 14-00 dolomite grey to cream-white . |glistening 30 serpentine tees 12-00!

1 Estimated. Determined by Miss D. M. Stewart, Mines Branch, Department of Mines.

THe state A RISA pS

The data igen which the 'ove estimates were made follow:

sit adjacent to drill hole 23. Horizontal extent fe 100 square feet. Proved depth, 90 Composition: saan, 60 per cent; magnesite-dolomite, 10 per cent; serpentine, 30 per cent.

Fy ope to diamond drill holes, Nos. 22, 24, and 25. Horizontal — 6, uare feet, Proved average depth, 1 13S feet, Com 2 ion: ma ite, 40 per cent; magnesite-dolomite, 25 per cent; serpentine, per cent.

Deposits adjacent to diamond drill holes i.us. 27 and 28. inslaenand en extent hole 27, 600 square feet, and hole 28, 600 square feet. Proved depth, eet,

ges magnesite, 50 per cent; magnesite-dolomite, 5 per cent; serpentine, Gaara of pond feet of magnesite and magnesite-dolomite in 1 ton, 12.

Unexposed Area Between Outcrops II und III.

In the unexposed area between outcrops II and III there are three diamond drill holes (see table v) which have disclosed the presence of approximately 90,000 tons of magnesite-dolomite.

The data on which this estimate is based follow: Horizontal extent, 20,000 square feet. Co! Soe um. e-dol 70 3¢ ber mposition: magnesit lomite, cent; mine, 3C per cent; num! pr get feet of eect iced agg a Me Rg 1 ton, hs

Outcrop No. III.

There is exposed in outcrop No. III (see outcrop III on Map 1679 and Table IV), approximately 25,000 square feet of rock surface composed as follows:

Magnesite, 65 per cen

Magnesite-dolomite, 13 per cent,

Serpentine, 30 per cent.

The eight drill cores Nos. 1 to 7 and 29, obtained from di::: ond drill holes in the deposit and its vicinity (see Table V), are comp. ed as

follows : Magnesite, 60 per cen Magnesite-dolomite, 13 per cent, Serpentine, 27 per cent.

In calculating the number of tons of magnesite and magnesitedolomite present in No. 3 outcrop it can be assuined, therefore, that the deposit as a whole contains at least 60 per cent magnesite, and 13 per cent magnesite-dolomite.

Since diamond dri! ole No. 29 was drilled in the clay flat outside the outcrop the horizonta: extent of the magnesite ore known to be present in outcrop No. III can be enlarged to include the material in the vicinity of this drill hole.

of

ond as

On the basis of the 'sregoing deductions the following data are available from which the number of tons of magnesite and magnesite-dolomite

in sight in outcrop No. III and its vicinity can be estimated: Horizontal extent, soem: ty feet. a avera depth, 1 see ro per cent. a gone of magnesite-dolomite, 13 per cent. Number of cubic feet of magnesite and magnesite-dolomite in 1 ton, 12.

The tonnage of magnesite and magnesite-dolomite in the deposit is

therefore, as follows: Magnesite, 187,500 tons. Magnesite-dolomite, 40,600 tons.

The preceding estimates of the tonnages of magnesite and magnesite-dolomite present on lot 15, range XI, Grenville, stated in summarized form are as follows:

Magnesite Magnesitedolomite. . tons tons

Number I outer Scie poke se Re aw CRP EA 192,000 37 ,000 et, £5 ONNONOIS. cy sc ee cca ce ees 39,000 18,700 Between outcrops Ti GMT erckeasesees: CO aes 90,000 Number IV outcrop... ci cic ce ccccneeeees 187,000 40,600 ROURE ret ore eee 418 ,000 186 , 300

oi Rd nel ow ieee

Table 1V, Physical Character and Lime (ov -xt of Samples of from Owlcrop No, 111, Lot 15, Range X!

Grenville Townshi — ; Se aera er a names — Pes cont Pex cont Fer cons Ca0 No. Colour Lust Grain of cob Material cobbed CaO in materi. al 1 cream-white.anow-white, 'glistening. . fine... 20 [grey magnesite- $008 13-00 and grey dolomite 2 pink, cream-white, and jglistening ... 9 ©. ...5: ; 2s magneaite- 7-00 13.90 grey eisai 3 cream-white and snow-jglistenin Of .seee| SO |grey magnesite- 8-00! 15-00 white, arey dolomite 4 HOF ivccsesccccsecsas [MMR 110 aan Serecerre re. ss 16°OO foc. cccsees ne) um j $s cream-white,snow-white, |gfiste: Lar as 40 greyanddullmag- 9-00 12-00 and grey j nesite-dolomite 6 cream-white and snow: listen fine 4. 20 grey magnesite- 5.957 12.00 white dolomite 7 pink, cream-white, and |glisteni: ' 15 grey serpentinous 6-00! 12-00 grey um magnesite-dolomite BS fehlte ccccseees {shining to ) leerpentine SE esacavcses wm 9 cream-white and snow-|glisteniay t ni veveoveee SSF? bisccces white 10 cream-white, pink, and/glister ere wagecunena rain Oscars sce snow-white iY cream-white and snow-|glistenin , 40 |coarsely crystallized| 7-008 14: white and grey magnesite- : dolomite 12 cream-white and snow-! glistening fin: 5 urey serpentinows 8-001 12.00 white magnesite-dolomite 13 snow-white to cream-glistening |fine 10 |grey and coarsely 7-00 12-00 white crystallized magnesite-dolomite 14 jerenme-wtiee to milk-glistening jfine Se See ere. PR crsrackexs + whit 1s ss (0 enow-glistening DOR isicces nil PLETE OA RTE alt SOOT ET TOE 16 |snow-white and milk- '|glistening |fine 40 |grey and coarse mag-| 3-00! 13-00 white nesite-dolomite 17 |snow-white and grey |glistening /fine 10 |coarse and grey mag-| 8-00! 14-00 ! nesite-dolomite 18 |snow-white to grey glistening eee 50 —_|coarse, dull-white 8-573 16-00 and grey magnesitedolomite 19 snow-white to grey .|glistening /fine $0 —_|coarse, dull-white 9-008 17-00 and grey magnesite-| dolomite AO TAOS cvev ie eset rer. glistening and dulljfine 50 light greenserpen- 13:00! tine a1 erey 0s padenes +++ /glistening to dull../fine ] 25 light green serpen-| 12-00! tine 22 pink to grey ++++ glistening \fine 10 arey magnate-del- 9-00! 13-00 te 23° |cream-white to milk- [glistening |fine 10 [grey magnesite-dol-| 9-00! 13-00 white and grey omite z 24 snow-white to grey |glistening |fine 25 oe ¥ magnesite-| 10-00! 15-00 lolomite 2s grey to snow-white |dull to glistening. .|fine 50 grey magnesite-dol- 14-008 18-00 eomite 25%. yellow serpentine 25°% 26 en ow-white to grey {glistening /finme 35 grey magnesite-dol-| 12-00! 15-00 omite 15%, serpentine 20% 27 snow-white to \fine rT ace a ire PES. ceupentes 28 snow-white glistening jfine 5 coarse and grey mag-| 10-00! 14:00 nesite-dolomite 29 enow-white /glistening (ae ee 20 coarse, shining, and} 11-00! 14:00 dull-white Ln RE A TNR nes tele ous fhas glistening to dull../fine 25 |serpentine. . x io oe Sees 31 wiik-while to grey jglistening to dull..|fine Pa Pewee Ted ee areas 32 snow-white to |fine 5 |duil white and shin-| 10-00! 18-00 i ing La cman omite 33 |snow-white to net ad S |coarse dolomite 10-00! 25-00 medium 34 snow-white and milk-glistening Pe. ere 25 —_—|coarse, dull-white, 11-00! 15-00

white and grey magnesite- Gaiomike

Range X! 3 Table 1V.—Continued, 4 Eos E & ; : Per cent Percent Per cent of or cont Cao e No. Colour Lustre Grain ofcob.| Material cobbed of CaO boot in mamateria' a H terial ' cobbe:!? 2 as eet EE wah A es . snow-white to milk-white <listening fine 60 coarse, shining, dull 10-008 18-00 13-00 2 j white, and grey| 135-90 a3 snow-white 0.6.65 jglistening . . jfine 5 coarse, shining, aw, 11,001 15.00 13-00 ; olomite 37 snow-white ond red... ..'glistening. .. . fine, F 25 coarse, shining, and| 9.008 14.00 bsoeenses grey magnesite-dol., 3 omite i 12.00 238 MG cave ds sn fleas v8 |glistening and fine to Yo woe} 84-008 12.00 Eat) apeckled grey... . listening. . .. fine and nil P noses f $8-68 f5, 12-00 40 cream-white, milk-white, glistening a fine to $ dull-white dolomite 15-008 22.00 a3 and grey shining coarse Sa reeey-white tosnowglistening... fine... S$ serpentine 6-008 Cabveees white 4 punrconite and milk-glistening pet waren ere nil ve cosereereoe| S878 1 roereery yy white i snow-white and e'oy glistening ne 25 dull-white magnes-| 9-0) 17.00 ve enevere j ite-dolomite 14:08 is .. +e dull to glistening. . fine to Ls ; 14-008 snow-white. . coon se {RlisteniAg. cc... eae 10.00 _snow-white to grey gliseening. .. oe Coe eee j 10-722 12,00 ismow-white, milk-white, listening Oe) keesareas 10-008 grey, amd pink — snow-white and milk-glistening... ee PR ere a alll CEE eee isnow-white and grey... .'glistening., Be 45 coarsedolomite 25%, 12.00! 20-00 i serpentine 20% treeere snow-white ,,- @listening,., /fime, mil |serpentine 12:00! snow-white, milk-white, glistening fine. ae 20 coarse, grey magnes-- 9-00! 18-00 veeewveeeie and grey ite-dolomite snow-white, mili-white,|glistening |finme MRM eiveses pesseet £10008 |snow-white {glistening nil pos ienvcse se sant O:G2# j 005 ry) 14-00 \snow-white. glistening, se eee re eee oe SS :. |snow-white, glistening. 25 |coarse, grey. serpen-| 10-00! 15.00 16-00 and grey tinous magnesitedolomite milke-white and grey... glistening 25 |serpentine... 17-00 |milk-white aad mrey.. \glistening nil Reale \snow-white, . veces {@listening 60 =grey maanesite H 15:00 <eees es § errr. a P + nil vine eae 60 ee ere 5 milk-listening fine. . : a ee rveeen 'snow-white and milk-|glistening ere Be OE Neeson vase CASON 9.00) 13-00 white 3 |milk-white ot wey.. . {glistening and dull/fine SM eohaa ven pyacerae 16 842 13-00 63 snow-white.. - . jghstening /fine nil ery nye ee ; 12-008 a 04 milk-white +-. glistening to |medium to BH fivccecsscesctcvnas 13.598 15-00 : shining coarse 65 milk-white and grey |glistening fine to § dark green serpen-' 13:00! 66 puemaree and milk-jglistening fine. et WHEY (Peeaenkas cu eacennns 7-072 white 15-00 7 {amow-white iglistening fine. . WANE Ls tycla rai ansceeh 7:00: 68 nore and milkjglistening jaime ME Eiacunkes cues 8-56? 'a white fs apelaces Ree 69 'snow-white and milk- {glistening and fine to 25 |coarse, grey, and ser-| 9-00: 16-00 14-00 white shining medium pentinous magnes- a We eect 14-00 70 —s milk-white glistening and fine to 5 serpentine 10-00! © 71 \snow-white {/glistening es 75 grey, serpentinous 10-00 17-00 Reecitttes magnesite-dolomite eee ee mare 18-00 See nn a ' Estimated. 25-00 ? Determined by Miss D. M. Stewart, Mines Branch, Department of Mines.

Table V. Summary Description of Diamond Drill Cores from Magnesite Deposits on Lot 15, Range X I, Grenville Township.

Magnesite con- Magnesite-dolo- Serpentine Total taining lessthan mite containing and depth of 12 per cent CaO', more than 12 per diopside, ole,

cent CaO!,

feet feet

nil 20

Unexposed area between outcrops II \and III.

Outcrop No. 111.

In mining the magnesite on the property the ordinary open-cut quarrying method with boom derricks and hoists is employed (Plate XI). The large masses of serpentine and dolomitic material encountered in the pits are unloaded into cars and transferred to the dumps directly. The magnesite on the other hand, is transferred to cobbing platforms where it is broken and cobbed.

The equipment on the property includes a number of boilers having a total capacity of 350 horse-power, 3 air compressors, 4 double drum hoists, 4 derricks, numerous drills, pumps, and other necessary machinery.

si

Camp buildings for the accommodation of 200 men have been built on the property and a light railway 14 miles in length has been constructed to the deposits from a point on the Canadian Pacific railway 2 miles east of Grenville station. In laying this railway long ties were used so that in the future if necessary it could be transformed to a broad gauge track. The necessary light locomotives and cars for the operation of the railway have also been procured.

Lot 15, Range X, Grenville Township.

Deposits of magnesite or magnesite-dolomite are known to occur in two localities on this property. One of these deposits lies at the north end of the lot and near the west side of the railway leading to the pits of the Scottish Canadian Magnesite Company on the adjoining iot in range XI. The other deposit occurs at the south end of the lot adjoining the deposits of the North American Magnesite Company on lot 15, range IX. The northern deposit occurs in association with an outcrop of diopside which extends for nearly 600 feet along the eastern edge of a ridge of garnet gneiss and quartzite. It consists largely of dolomite and, while material of better quality may possibly underlie the clay flat adjoining the deposit, in its exposed portions at least it is not sufficiently extensive to be of commercial! value.

The southern deposit on this property lies on the northern edge of the ridge of magnesite, magnesite-dolomite, and serpentine, which outcrops at the north end of the McPhee property (lot 15, range IX, Grenville township). The extent and geological relationships of the occurrence are indicated in outcrop No. 4, on Map 1679, and the physical character and lime content of samples collected from the surface of the deposit are given in Table VI. Of the exposed portion of the outcrop, 35 per cent consists of magnesite containing less than 12 per cent CaO; 55 per cent consists of magnesite-dolomite containing more than 12 per cent CaO; and the remaining 10 per cent consists of serpentine. Since the portion of the deposit hidden by rock debris underlies the bottom of the pit where the material of best quality probably occurs, it may be assumed that the proportion of magnesite relative to magnesite-dolomite and serpentine present in the exposed portions of the deposit is at least not less than that for the whole deposit; and from the following data the tonnage of magnesite in the deposit can be estimated.

Area, 30,000 square feet. Percentage of magnesite containing less than 12 per cent CaO, 35. Percentage of te x Sepa containing more than 12 per cent CaO, 5S. Assumed depth, 25 feet. ; aes of magnesite, 2,500 tons.

antity of magnesite-dolomite, 4,000 tons.

A few tons of magnesite were mined from this deposit by the Scottish Canadian Magnesite Company, owners of the property, during the winter of 1915, but since that time no work on the deposit has been attempted.

Table VI. Physical Character and Lime Content o— of Magnesite from Outcrop of Magnestte on Lot 15, Range X, Grenville Township.

No. Colour Lustre Grain Percent of Per cent of cob. CaO 1 speckled-grey dull fine nil 18-00! 2 snow-white glistening fine tin! 12-00! 5) milk-white glistening fine nil 11-56* 4 milk-white glistening fine nil 12-00! 5 speckled-grey dull fine nil 18.00! 6 speckled-grey glistening to dull] fine nil 15-00 7 milk-white glistening fine nil 13-78? 8 milk-white and glistening fine nil 14-00 grey 9 milk-white and glistening fine nil 11-00 grey 10 speckled and dull fine nil 15-00 grey 11 snow-white and glistening fine nil 10-29% milk-white 12 snow-white glistening fine 10 11.00 milk-white 1 Estimated.

3 Determined by Miss D. M. Stewart, Mines Branch, Department of Mines.

Lot 15, Range Ix, Grenville Township, Mcphee Property.

The principal deposit on this property occurs at the extreme north end of the lot. At this point a ridge of magnesite and magnesite-dolomite approximately 1,000 feet long and from 100 to 300 feet wide extends northeasterly along the east shore of Whiterock lake. The physical character and the lime content of samples from the surface of this ridge are given in Table VII, and the proportions of magnesite, magnesitedolomite, and serpentine contained in the diamond drill cores (drilled by the Harbison-Walker Refractories Company of Pittsburg) are summarized in Table VIII. The sample areas to which the numbers in Table VII refer are shown in outcrop V on Map 1679. The geological relationships of the deposit are shown in Map 1674.

Northern Part of Ridge.

In the northern part of the ridge there is a total area of approximately 75,000 square feet, of which 10,000 square feet (areas 1 to 53, outcrop V, Map No. 1679) are composed as follows:

Magnesite containing less than 12 per cent CaO, 25 per cent. Magnesite-dolomite containing more than 12 per cent CaO, 40 per cent. Serpentine, 35 per cent.

ately crop

In the six diamond drill cores drilled in this part of the ridge (see table VIII) the proportions of magnesite, magnesite-dolomite, and serpentine are as follows:

Magnesite, 17 per cent. Magnesite-dolomite, 57 per cent. Serpentine, 26 per cent.

It might be pointed out in this connexion, however, that at least ten additional diamond drill holes would be required before the extent and quality of the material contained in the northern part of the ridge on the McPhee property can be regarded as fully determined.

Since the areas on the surface of the ridge from which samples were taken (Nos. 1 to 53) are widely separated, it is probable that the average percentages of magnesite and magnesite-dolomite obtained in these samples are closer to the percentages actually present (in the upper parts of the ridge at least), than the average obtained from the diamond drill cores. If, in estimating the number of tons of magnesite and magnesitedolomite present in the northern part of the ridge, therefore, the lower average obtained for each constituent (17 per cent for magnesite and 40 per cent for magnesite-dolomite) be assumed to be present, it is reasonably certain that the resultant estimates will represent the minimum number of tons actually present.

The data from which a minimum estimate can be made follow:

Horizontal extent, 75,000 square feet.

Proved average depth, 100 feet.

Assumed average proportion of magnesite, 15 per cent.

Assumed average proportion of magnesite-dolomite, 40 per cent. Number of cubic feet of magnesite and magnesite-dolomite in 1 ton, 12.

On the basis cf the preceding data it is estimated that 94,000 tons of magnesite and 250,000 tons of magnesite-dolomite are present in the northern part of the McPhee outcrop; but, until a market is procured for the magnesite-dolomite, it is probable that not more than 25,000 tons of the 94,000 tons of magnesite in the above estimate could be profitably mined.

Southern Part of Ridge.

In the southern part of the outcrop on the McPhee property there is an exposed area of 32,000 square feet, composed approximately as follows (see areas 54 to 135, outcrop V, map No. 1679, and table VID:

Magnesite, 70 per cent. Magnesite-dolomite, 20-per cent. Serpentine, 10 mer cent.

Within this area two diamond drill holes, Nos. 39 and 40, have been drilled. Of these Ne. 39-was drilled to a depth of 180 feet, but No. 40 was started only few feet to the east of an eastward dipping lens of

dolomite (see Map 1679 area 97) and in consequence dolomite was encountered at a depth of 15 feet, and after proceeding 9 feet in this material drilling was discontinued. There is, therefore, no information available with regard to the extent of the magnesite on the southern part of the McPhee outcrop at depth except in the vicinity of drill hole 39, and, on this account, the following estim:te of tonnage in sight is probably somewhat lower than the actual amount present.

On the basis of the usual assumptions the tonnage of magnesite and magnesite-dolomite in sight in the southern part of the McPhee outcrop can be determined from the following data:

Adjacent to hole No. 39: Horizontal extent, 5,000 square feet. Proved depth, 200 feet. Assumed proportion of magnesite, 70 per cent. (Table VIII.) Assumed proportion of magnesite-dolomite, 15 per cent. (Table VIII.)

Not adjacent to hole No. 39: Horizontal extent, 27,000 square feet. Assumed depth, 50 feet. Assumed proportion of magnesite, 65 per cent. (Table VIII.) Assumed proportion of magnesite-dolomite, 15 per cent. (Table VIII.) Number of cubic feet of magnesite and magnesite-dolomite in 1 ton, 12.

:

The number of tons of magnesite and magnesite-dolomite present is, therefore, as follows:

Locality Magnesite, Magnesitedolomite, tons tons Adjacent to hole 39 0.. 58,300 12,500 Portion not adjacent to hole 39 73,100 16,900 FORK oooee ca ives Sashes 131,400 29,400

In the southern part of the McPhee property a small mass of magnesite was observed in association with diopside on the west side of the road to the property at a point approximately 300 yards south of the main outcrop, and farther southward on the east side of the road dolomite is exposed for a width of approximately 20 feet. While these occurrences are of interest in that they indicate the possible occurrence of magnesite underlying the clay flat at these points, the material actually exposed is not of sufficient extent to be of commercial importance.

A summarized statement of the tonnage of magnesite and magnesitedolomite known to be present on the McPhee property is as follows:

Magnesite, Magnesitedolomite, tons tons Northern part of outcrop 94,000 250,000 Southern part of outcrop 132,400 29 ,400

POR isa oases woke 226,400 279,400

z '3 &

unrial ible the ,on bly

and Trop

nethe the 1ite ces site 1 is

ite-

q Tobie VII. PRG CRS 8 Lines Conieat AOE eens ome Baguette Ceterebe oe Eat 45, Range 1X,

snow-white to milk-white apeeine Ba tale fine snow-white to rads

ow-white to milk-white Stains aoc aree ee snow-white to milk-whitejglistening

SO Sees el emcee grey " SRR SERA meee to cream- Sites peat nse fine to whit 'snow-white. . ea milk-white and grey... .

grey and snow-white gtey and enow-white. ...

grey,serpentinous magnesite-dolo:

listening and ae Se Creare reer eee:

snow-white 8 shining medium

Table VII.—Continued.

eee

Lustre Grain niomews. 69 fine and medium seeceess-/fine and medium isnow-white, milk-white,|glistening fine to and grey medium ranulated cream white, milk-white . glistening WES cos cream white to milk-glistening and fine to white shining medium cream-white, medium to/glistening and fine to grey shining medium cream-white and snow-|glistening |fine white cream-white to milk- |glistening fine to white and grey medium cream-white and milk-jglistening eeanees white cream-white and grey...jglistening oT Aes snow-white, milk-white,|glistening and fine to and grey shining medium snow-white to grey |glistening je to medium snow-white and grey |glistening eer ae tudes Se eTeT ee cream-white and milkwhite cream-white and milk-|glistening ee white snow-white and grey... .|glistening fine to medium cream-white and grey...|glistening fine and medium snow-white, milk-white,|glistening es and grey snow-white to milk-white/glistening fine to medium milk-white fine, granulated snow-white and grey ...jglistening eee isnow-white and grey... .|glistening median to coarse cream-white to snowjglistening fine to white medium cream-white and snow-iglistening fine to white medium isnow-white glistening Re oe SET CE on glistening to dull..|fine snow. white and' milk-glistening TONE 65 5555553 white cream-white to grey glistening 1 eee snow-white glistening... a: epee white and grey shining and dull. .|medium to coarse snow-white, milk-white,|glistening oe and grey

cream-white, "miik-white, glistening. ere ee

and snow-white snow-white and grey... .|glistening cream-white, snow-white,|glistening. . and milk-white

snow-white, milk-white ./glistening fine and medium snow-white and milk-glistening eee white snow-white and milk- (glistening Lee white snow-white and milkjglistening \fine and white medium snow-white, milk-white .|glistening ..|fine isnow-white and grey... .|glistening and dull fine s

white

Per cent of cob.

nil nil ail nil

nil nil

Material cobbed

grey magnesite-dolomite

grey serpentinous magnesite-dolomite

coarse, grey dolomite 10%, yellow serpentine 5%

grey, serpentinous magnesite-dolomite

yellow serpentine and grey magnesite dolomite grey magnesite-dolomite

grey,serpentinous magnesite-dolomite

grey, serpentinous a yellow serpentine. .

coarse, white dolomite

coarse dolomite 15%, serpentine 5%

coarse dolomite.

yellow serpentine. . :

grey magnesite-dolomite

yellow serpentine. . yellow serpentine...

dull white magnesite dolomite

iserpentinel0%, coarse dolomite, 10%

Per cent of CaO "17-008 15-00! 12-00! 11-00! 10-44? 12-00! 11-00!

Per cent of CaO in ma terial cobbed

Table V11.—Continued.

Per ce: Per cent of Per cent ol No. Colour Lustre Material cobbed of CaO CaO in ma- CaO in ma cobbed! rial cobbet: 99 |snow-white, milk-white, |glistening and grey serpentinous 10-00! 15-00 and arey magnesite-dolomite 90 |snow-white and grey... . glistening. . PRT ee pep ART '5 91+ |snow-white and grey . -|atening and |medium...| nil [000/11 117: ; 13-00! : shining 92 |snow-white, milk-white,|glistening /fine nil 10-00! and grey 93 grey and snow-white jglisteningand finland nil 14-00! 4 shining E 9 grey /hining and dull...jcoarseeand nil 18-00! 98 |cream-white, snow-white, glistening fine green serpentine. . 9-00! 16-00 % cream-white,enow-white, glistening 8-00! grey 97 |white glisteni 22-00! 98 milk-white, oe 'and 10-00: 16-00 a and wee Gey shining 99 ite, milk-white, siistening. Sica ie Ae TATE RTE MEM Mellor aie e yeresoune Se 6-00! — cream-white 100 |snow-white and grey... .|glistening 9-00! sah 101 ema whine ne tele Ass tere Se ae Scie ces eect 6-072 wi 102 |snow-white, milk-white,|glistening 7-00: y a] adliewiiiie aed aeep ibeniie Bae Tho wr 10-00! 105 snow-white iglistening coarse dolomite con-| 7-80? taining pyrite. . 13-00 ome ie ent milk- On Sepa SB he oe esac -00! Fl FE grey... ./glistening fine ere 10-00! isnow-white and grey... .|glistening Scion Serpentine: 12-00! isnow-white and grey... ./glistening |fine dull white dolomit2.| 10-00! 18-00 oe snow-white and grey... .|glistening . |fine ee eee oe ae eee iglistening pea Loaf 9-402 milk-white 9 001 grey... 11-00! grey. 25-00 milk-whit: hee 8-842 x shining 15:00 f @ 1-6 |cream white, snow-white,/glistening and fine ) nil 000, 6-073 Z grey shining 117 |snow-white |glistening |fimeand nil , 3:93! 28-00 @ 118 enow white and milk- |{glistening [medium nil 7-008 c white 119 a and milkening: :::; ie 1 RR oc cc ci awed 9-001 120 a ree milk-glistening yellow serpentine 10-00: 121 |milk-white re eee a ee Ge ne ee oe 10-001 122-\ |snow-white and milk-glistening /fine and 10-00! 123 white 124 \snow-white. . ioe ss SMa ORE fos igeteris aeees. 8-00! 125 |snow-white and grey... ./glistening .. green serpentine... 9-00! 126 ieeyieee= and milk-glistening... . green serpentine. . 10-00! milk-white and grey /glistening /finland nil 11-00 129 a milk-white,| glistening. . . grey serpentine 10-00! and grey snow-white and re, dull ening MMB PAR fond xd sec eyy coe 16-00! i i hite,|glistening j@rey magnesite-dol-| 11-00! 14-00 ; omite glistening Ltd reps oes Seat ! glistening grey magnesite-dol-| 9-00! 14-00 o snow-white and milk- 'glistening

Table VIII. Summary Description of Diamond Drill Cores from Magnesite Deposit on Lot 15, Range 1X, Grenville Township.

Magnesi Total agnesite mite ota No. containing less Average containing more —— depth of of than 12 per cent CaO content of than 12 per cent ee le, hole CaO, magnesite CaO, feet feet feet feet 33 23 9-09 86 31 140 34 21 10-48 53 10 85 35 9 9-60 28 43 80 36 9 11-47 30 46 85 37 15 10-80 35 7 57 38 15 9.95 79 6 100 39 1404 7-40 324 7 180 15 7:33 Fie od. 24

The magnesite is mined at the McPhee property as elsewhere in the district by the open-cut method. The magnesite is cobbed as broken down at the pit's face and loaded directly into wagons (or sleighs in winter) and the waste rock is carted to the dumps.

The equipment on the property includes a 10-ton keystone kiln, four retort furnaces, a mill for grinding the calcined magnesite, a cableway for hoisting the ore into the kiln (Plate X), a number of boilers, steam drills, pumps, and other machinery necessary for quarrying operations. Camp buildings having accommodation for 100 men have been erected on the property and a road 11 miles in length has been

constructed from the magnesite deposit to the Canadian Pacific railway at Calumet.

Lot 13, Range Ix, Grenville Township.

The southern part of this lot is occupied by a high ridge of garnet and granite gneiss on the northern slope of which, adjoining the clay flat which extends along Magnesite creek, outcrops of dolomite are exposed. One of these deposits, situated on the east side of the lot about 200 feet to the north of the road crossing the property, is approximately 40 feet long and 20 feet wide; and another occurring about 100 yards farther down the hill to the northwest is exposed for 30 feet in the bottom of a trench. The dolomite contained in these deposits is a coarsely crystalline white variety containing disseminated grains of wax yellow serpentine and flakes of graphite. Sin-e dolomite has little or no commercial value. these deposits are of importance at the present time only in so far as they indicate the possible occurrence of magnesite in their vicinity. If, in the future, a market for dolomite should be procured, they might bec: 1:

valuable; but additional development work would be required to prc. their extent.

1 Analyses by J. T. Donald and Co.. Montrea!.

broken ghs in

cableoilers, rrying

have

ilway

garnet

Lot 16, Range Ix, Grenville Township.

This lot lies on the eastern margin of a batholithic mass of granite gneiss and, except at points along its eastern boundary where embayments in the batholithic margin occupied by rocks of the Grenville series occur, is entirely underlain by gneiss. The most extensive area of rocks belonging to the Grenville series, on the property, underlies a drift covered depression at the southeast corner of the lot and it is in association with these rocks that a mass of dolomite and magnesitedolomite has been discovered.

At the time the property was examined by the writer in August, 1916, the only indications of magnesite at this point were a few large boulders of magnesite in the drift and a northeasterly trending ledge of quartzite and diopside about 3 feet wide and 20 feet long, exposed in the bed of a small creek. There was a parallel, drift-covered ridge about 40 feet wide and 300 feet long adjoining this outcrop on the southeast, however, which had the elliptical form and conformable trend common to all the magnesite deposits. A pit was excavated in the drift by Messrs. Fitzsimmons and Boshart with the result that a deposit of magnesitedolomite and dolc'te containing included masses of diopside was disclosed. When the deposit was visited by the writer in January, 1917, a pit approximately 30 feet square had been excavated, the bottom of which was underlain entirely by this material, but up to that time no No. 1 magnesite had been discovered.

Lot 11, Range Viii, North, Grenville Township, Campbell Property.

At a distance of 100 feet to the north of the road which crosses the south end of this ot a dolomitic magnesite was exposed along the whole length of the bottom of a 50-foot trench. This dolomitic magnesite is a medium-grained, uniform, white, crystalline material containing disseminated grains of wax-yellow serpentine. The lime content of the doiomitic magnesite has not been determined chemically, but the physical character indicates that it probably contains at least 20 per cent.

Lot 12, Range Viii, North, Grenville Township.

The deposit of magnesite-dolomite on lot 12, range VIII north, Grenville township, consists of a group of large boulders situated near the south end of the lot at a point a few hundred fect east of Calumet creek and about 400 feet northwest of the dolomitic magnesite exposed in the bottom of a trench on lot 11. Whether the boulders comprising this deposit have been derived from the underlying bedrock cannot be positively determined, but their similarity to the bedrock a few hundred feet eastward indicates that such is possibly the case.

A sample of the boulder material, collected by R. L. Broadbent, was analysed by R. A. A. Johnston of the Geological Survey with the following result:

Lot 11, Range Viii, South, Grenville Township.

Dolomitic magnesite is exposed in the bottoms of a pit 25 feet square and a trench 20 feet long, on the western slope of a drift covered ridge, near the northwest corner of this lot, and about 200 yards south of the dolomitic magnesite exposed in the bottom of trench on the Campbell property. The material exposed at these points is similar in every respect to the dolomitic magnesite found on the adjoining Campbell property and indicates that there is possibly a very extensive area of this material in that locality.

Lot 12, Range Viii, South, Grenville Township.

An enormous boulder of fine, white glistening magnesite also occurs on lot 12, southwest of the exposure on lot 11, and about 200 feet west of Calumet creek. The larger part of the boulder is buried in clay and sand so that neither its whole extent nor its relationships to the underlying

bedrock have been determined. A shipment of 52 tons of magnesite derived from this boulder was

made by Messrs. Fitzsimmons and Boshart during the summer of

Lot 9, Range Xi, Augmentation Of Grenville.

Serpentinized dolomitic magnesite occurs on this lot on the east shore of Papineau or Commandant lake. At the point examined by the writer the dolomitic material formed a low point about 100 to 200 feet wide and several hundred feet long projecting northward between a small bay and the main expanse of the lake.

An average sample collected by the writer from the deposit and analysed by H. A. Leverin of the Mines Branch had the following composition.

A deposit of similar material was reported to occur inland from the lake, but was not examined by the writer.

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Lot 21, Range I, Harrington Township.

Near the north end of this lot a triangular shaped mass of crystalline limestone belonging to the Grenville series projects into Rouge river forming what is generally known as Marble rapid. On the west the limestone adjoins a ridge of Grenville quartzite and along this contact there is a highwater channel so that the limestone mass becomes an island during periods of flood.

This insular mass of limestone has an approximate length of 250 feet and a width of 100 feet. It consists of medium-grained, crystalline limestone containing disseminated grains of wax yellow and reddish brown serpentine, and numerous nodular or lenticular masses of serpentine and coarse white dolomite. At one point an included mass of crystalline porous calcite was also observed. The disseminated serpentine is concentrated in bands which trend in a northeasterly direction and dip to the northwest thus conforming in their strike and dip to the structure of the adjoining quartzite. Near the north end of the mass a crumpled lens of graphitic coarse, white dolomite about 12 feet long was observed to be enclosed in banded limestone, the crumplings in which conformed to the plications in the dolomite mass, thus indicating clearly that the present form of the dolomite mass has resulted from deformation.

As far as was observed there is no magnesite in this locality and the amount of dolomite present is very limited. The deposit is of interest,

however, in that its lenticular and banded structure is strikingly similar to that of the principal magnesite deposits of the district.

Lot 7, Range X, Grenville Township.

Magnesite in place was not observed on this lot, but a number of boulders of fine glistening white magnesite of excellent quality occur near the north end of the property, which are of interest because they indicate the presence of an undiscovered deposit of magnesite in the district.

In the Grenville region the direction of glacial movement was approximately from north to south so that all boulders of magnesite which have been transported are found south of the deposit from which they were derived. It is obvious, therefore, that the boulders found on lot 7, range X, Grenville township, have not been derived from any of the known deposits in the district, but from an undiscovered deposit occurring either at the nofth end of lot 7 or northward in the direction of Green lake.

Chapter V. Summary And Conclusions.

Some of the more important results of the study of the character, extent, and relationships of the Grenville magnesite deposits briefly stated are as follows:

The deposits are of early Pre-Cambrian age and occur in association with the metamorphosed group of sediments (crystalline limestone, sillimanite-garnet gneiss, and quartzite) known as the Grenville series.

All of the deposits so far discovered in the district occur in the major valleys in which stratified marine clay and sand have been deposited. Through this material the deposits outcrop in ridges or groups of ridges up to 1,000 feet in length and 300 feet in width.

The ridges in which the magnesite is found are composed mainly of magnesite, dolomite, serpentine, and diopside. The proportion of magnesite free from dolomite or dolomite free from magnesite in the deposits, however, is small, these minerals occurring for the most part intimately intermingled in varying proportions.

The deposits have all been so intensely deformed since their formation that masses of serpentine, dolomite, and other variations which they contain have been squeezed out into lenses.

The study of the character,and relationships of the deposits has led to the conclusion that they are of metamorphic origin, and have been formed by the replacement of the limestone member of the Grenville series through the agency of magnesia-rich solutions.

While the magnesite everywhere includes more or less dolomite, diamond drilling and other development work have shown that extensive masses of magnesite are present in which the lime content resulting from the presence of the dolomite averages from 7 to 10 per cent.

A summarized statement of the number of tons of magnesite and magnesite-dolomite in sight in the various properties is as follows :!

Magnesite contain- Magnesite-dolomite ing less thar 12 per containing more than Property cent CaO, 12 per cent CaO,

Lot 13, range I, Harrington township. ... Lot 18, range XI, Grenville township. ... Lot 15, range XI, Grenville township. ... Lot 15, range X, Grenville township

Lot 15, range IX, Grenville township. ...

1 It must be noted in this connexion that these estimates have no definite 'relationship to the amount of magnesite present on the various properties since some denosita have heen more extensively developed by diamond drilling and other development operations.

E

Of the above total, however, there is approximately 69,000 tons of magnesite on lot 15, range IX, and 10,000 tons on lot 15, range XI, that could not be profitably mined unless a market for magnesite-dolomite was procured.

Since the magnesite and magnesite-dolomite are, on the whole, less resistant to erosion than either the serpentine or the rocks of the Grenville series with which the deposits are associated, it is probable that the outcrops in which the magnesite occurs have little or ne relationship to the actual distribution of the magnesite and that extensive masses of magnesite occur underlying the clay flat adjoining the outcrops.

Since the magnesite deposits are generally associated with the rocks of the Grenville series and since these rocks usually underlie valleys, the most favourable localities for prospecting for magnesite are the valleys, and especially those valleys where limestone and other members of the Grenville series are known to be present.

The occurrence of boulders of magnesite in localities where they could not possibly have been derived from the known occurrences of the material indicates that there are other undiscovered deposits of magnesite in the district.

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A. Caleined Grenville magyesite-dolomite; dark. magnesite; light, dolomite; natural size. (Page 26)

B. Caleined Grenville magnesite, showing inclusions of dolomite. (Page 26.)

MICROCOPY RESOLUTION TEST CHART (ANSI and ISO TEST CHART No. 2)

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A. Calcined Grenville magnesite-dolomite; dark, magnesite; light, dolomite; black spots, serpentine; enlarged two diameters. (Page 26.)

B. Grenville magnesite-dolomite calcined in a reducing atmosphere; enlarged two diameters. (Page 26 )

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Adame, ¥ 12 yan nner Te UR Gen tad

p "egg yn EN IETS OF oe ce ens cancion al Analyses of Californian magnesite

® Grecian magnesite 0: ee - fs hydromagnesite from Atlin, B.C... ideas op SRS a eae apheresis

. is " Dobbie mine. .

. . e " magnesite outcrops alert

Ls ws ® Orangedale, N.S...+.+sseeergre ve

. - " outcrop No. 1, lot 15, range

. bs . " outcrop No. Lil, lot 15, range XI, Gre

: . outcrop on north half of lot 18, range

Beet En Ee Ceos Eerste Ee (Eves Ss

" slag, Steel Company of Canada SSE anes

. " typical Austro-hungarian magnesite 5- +--+ Apatite. ... nate his teas team eee rmne hE Oe Lene S Mate ME nc Sivenasauae test unrtnenteah ae SPT ANT

Augmentation of Grenville, lot 9, range XI 'Austria-Hungary magnesite +++:

B. Barlow, A. E. . RRS ean Re 1g GS ISO COC OCIA. omen pert ae 31 nin niall RR Or ree ae eee hee eta SOE 19 Bolton tp., Que... - a eee Mi pioh bonis Meera ce CL LOOSE AAA AY 14 escaty "sy URI ROE Eee anon ebay aun er eee 17, 59, 60 Bridge River district, B.C... 15

Broadbent, R. L ; Buckingham series

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D. ee, AER See ort Cars Kana eate nee g ree Dead burned magnesite s.ssccssrersereneer Teformations ce ocwe seen eerenee Riga VaGe tee ee DRAINS os op cicei scar eiccee een ew seers tenes FET Distribution of magnesite :-ssrcccrseersss Pit bdh Wie. odes eter bcs naness PERSE HNEEAET TEE a ee "aN RR Re IRD ERR Pree Cn dan cbt ne ie ee eae Donald, J. T. and Company 9--7-s00sn

Drill cores from magnesite deposits on lot 15, range IX, Gren p Y " magnesite deposi lot 15, range XI, Grenville tp ; Mane ,

Fitzsimmo.'s, Mr Fluorite. Frechette, Fusion point.

Germansen creek, D.C... 06. ic cece eee e eee eenes Glacial. . 'we Granite . ees @ — syenite gneiss... 6.6 cece eee ee CAONIER ce eens ae ; Grecian magnesite Grenville Lumber Company a eee township

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Grosvenor, W. M. Gwillim, J.C...

Harbison-Walker Refractories 00555000055 Harrington township +-: # "Iet 13, range I.. s " Cy: Pere Hayes, A.0 0.000 ccc cer gecneeeenee History of magnesite mining in Grenville district

Ilecillewaet, B.C ret eee International Magnesite Company... 0.6.00 :0 sree rere etree

Johnston, R. A. A..

Lac des Mille Lacs, Ont

Lenticular form

Leverin, H. A

Lime content

Logat, Wi, Sli ci ccs t ree rec tee eise ine

Melkman, Metamorphic pyroxenite.

New Brunswick eet North American

Grenville tp ot

Nova Scotia magnesite Steel and Coal ESE

Ontario magnesite fo ephuaeexae cere — le, N F

Suter beside:.

Folger

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Phlogopite. . Pleistocene. . tease Pre- Camb-ian 'intrusives.

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Scapolit Scottish

GFin we ME oo aces seen te Cr Te GSI NEE Shawinigan Electrometals Company

Sources of be South Grenville

Stewart, Structure

Summary and conclusions Sutton tp., Que cee r eee re etre erertre ts Syenite

Tourmaline Turner, N. L

United States magnesite Uses of ma: TT ap con nomenon s ou Ors cease ealgcallaROOUS. s-foias sano es Soe diners catenins Wee HEARERS CO te EES NS

Whiterock lake 00:seeeeees Wood pulp by the sulphite process, manufacture of

Z eee Vrs psteg

Elevation 573 feet

Geologica/ Survey, Canada. Diagram showing magnesite deposits, Lots [5, ranges IX and X,, Grenville township, Argenteui| Scale of feet

in See. SON Se. a.

7a accompany Memoir by M £.Wison.

Legend

Bouldery drift

Magnesite, magnesite - aotonte and Sots

f, Grenville' series

ee Quartzite

[2— vertical strata 703 Dip and strike

Dumps

Tramways

Catalogue No. /674 posits, Reprint enteui/ county, Quebec.

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Outirgn

Geological Survey, Canada

Diagram showing magnesite outcrops in Grenville tows

Scale of feet

To accompan vy Memoir by ME Wilson ¥ Pane ee eceeenre eee, SE

Z egeind

Cp site

flock debris

Mapresite area a 3 rel er te sa rpie, Coben ted

Vert:ca/ strata

Catalogue No 1679