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By A. N. Shen

Fe3A1 intermetallics are potential inexpensive candidate for hot applications. In this project, torsion tests on hot-rolled and annealed Fe3A1 (Fe-15.5A1-5.8Cr-1.0Nb¬0.05C) were carried out over the ranges 750-950°C and 0.01~1s-1 . The experimental results showed that when peak stress op>90MPa (LogZ>16s-1 , Z: temperature-compensated strain rate), specimens cracked at randomly low strains. Optical microscopy exhibited original elongated grains and many grain boundary cracks associated with segregation. With op<40MPa (LogZ<16s-&apos;), specimens deformed with low random op but considerably high fracture strains; slowly propagating cracks may explain the reduced flow stress. Optical microscopy showed both elongated grains and equiaxed subgrains with some indications of geometric dynamic recrystallization (gDRX) and of static recrystallization (SRX). Compression tests gave higher stress with little effect of the preexisting cracks. The activation energy Quw of current material in satisfactory torsion and compression tests is about 10% higher than previously published. Fe3A1 has body-centered cubic structure in the experimental range, so it was compared with ferritic stainless steel 434C (Fe- 16.55Cr-0.96Mo-0.21Ni). Constitutive constants and restoration mechanism are compared between these materials. While Fe3A1 is hardly a light metal, it is considerably lighter than most steels. Furthermore, like the other body centered cubic metals (BCC) (a-Fe, ß-Ti, ß-Zr and ß-brass), it exhibits a high degree of dynamic recovery (DRV) like Al alloys, producing easier hot workability than that of austentic stainless steels.

Jan 1, 2007

By R. P. D. Graham

It is almost exactly two hundred years since the foundations of the mining and metallurgical industries in Canada were laid. There &apos;."&apos;as nothing spectacular about this early start. It had to do with the most basic phases of these industries-the mining of coal and iron ore, and the manufacture of cast and wrought iron. At several points along the coast of Cape Breton island, coal seams may be seen outcropping quite conspicuously, and it is probable that they had been observed, and possibly worked in a small way, in very early times. However that may be, these coal seams have the distinction of being the first in North America of which there is any printed record, reference to them appearing in a volume by Nicolas Denys which was published in Paris in 1672. Regular coal mining in the district did not commence until about fifty years later, however. The metallurgists started their operations along the north shore of the St. Lawrence river. Here, at many points between Montreal and Quebec, are to be found deposits of bog iron ore, and in 1 730 a furnace for smelting such ore was established on the St. Maurice river. The St. Maurice forges continued in operation until 1880, and throughout that long period they were famed for the fine quality of castings produced, and also for a-superior wrought iron.

Jan 1, 1924

By Ian R. Morrison

"Abstract - The Izok Zn-Cu-Pb-Ag volcanogenic massive sulfide deposit is located 265 km south of Kugluktuk (Coppermine), Nunavut Territory, Canada, in the west-central Slave structural province. The Izok deposit is owned 100% by Inmet Mining Corporation and represents one of the largest undeveloped zinc-copper resources in North America. The Izok deposit is hosted within and near the top of a thick sequence of predominantly felsic pyroclastic rocks of late Archean age. The hanging-wall stratigraphy includes additional felsic volcaniclastic rocks, andesitic and basaltic flows, thin sulfide-rich iron formations, and turbiditic sedimentary rocks. The felsic volcanic rocks are intruded by intermediate dikes and sills, followed by gabbroic dikes and sills. Both intrusive suites are interpreted to be volcanic feeders to the overlying flows. All lithologies are subsequently cut by younger, irregular, granitic pegmatite and diabase dikes. The volcanic and sedimentary rocks are regionally metamorphosed to pyroxene hornfels grade. The massive sulfides occur within a large (kilometer-scale) Na-depleted sericitic alteration zone. The immediate footwall and hanging-wall rocks to the deposit are characterized by zones of muscovite- biotite-sillimanite, lesser chlorite-biotite-cordierite, and locally intense silicification and sodium metasomatism. All lithologies have been affected by younger Ca-metasomatism. As currently defined, the Izok deposit comprises a cluster of five complexly zoned composite lenses: the Northwest, North, Central West, Central East, and Inukshuk lenses. The first four lenses are amenable to open-pit mining, whereas the Inukshuk lens will require underground development. The total indicated mineral resource presently stands at 16.5 million tonnes with a grade of 2.2% Cu, 11.4% Zn, 1.1% Pb, and 60 g/t Ag. Inmet Mining Corporation is presently reviewing the economic feasibility of developing the property."

Jan 1, 2004

By John D. Godfrey

A brief account of economic developments in and around northeastern Alberta is presented and mention is made of mining and industrial developments currently of interest in the area. Planned and projected operations are briefly discussed for this region. The history of geological surveys and mining activities in the Shield area of Alberta and the adjoining parts of Northwest Territories and Saskatchewan is traced. Reassessment of the presently-known economic picture of northwestern Canada in conjunction with some recent information on Precambrian structures of northeastern Alberta points to some interesting mining possibilities, particularly in and around that province.

Jan 1, 1960

By Peter R. Drummond

THE paper consists of four sections: (1) a discussion of early work; (2) presentation of the results of a chemical investigation of Falcon-bridge nickel-copper blast-furnace matte; (3) application of the results of this investigation to mattes in general; and ( 4) a summary of conclusions. All general discussion will be confined to the fundamental system of ferrous-cuprous sulphides (FeS-Cu2S). Nickel-, lead-, and zinc-bearing mattes will be treated as minor varieties of the parent system. DISCUSSION OF EARLY INVESTIGATIONS Matte investigations may be divided into three classes: first, those treating the sulphides as alloys-theoretical studies of the system FeS-Cu2S, such as those of Hofman (ll)t or Carpenter and Hayward (2); second, chemical research on mattes made under smelter conditions, such as that carried out by Hawley (3) or Avetision ( 4); third, combinations of the . above, such as the investigations of Gibb and Philp (5) or Fulton and Goodner (6). Much research in the first of these classes, including determinations of . freezing points and of data for structure-composition diagrams of the system FeS-Cu2S, was carried out in the period 1890-1910. LeChatelier and Ziegler (1, 13) proved that FeS, when heated alone above its melting point, dissociated in part, and Friedrich ( quoted by Fulton, 6) showed the same for Cu2S. The reactions may be expressed by the following equations: [xFeS yFe + yS (volatilized)+ (x -y)FeS xCu2S )&apos;Cu+ yS ( vohtilized) + (x -)&apos;)Cu,S ] Sulphur is lost by volatilization, leaving a melt of metallic iron plus ferrous sulphide in the one case, and of metallic copper plus cuprous sulphide in the other. If the mixed sulphides are heated far above their melting points, there results either an iron-rich matte containing Fe-FeS-Cu2S or a copper-rich matte containing FeS-Cu2S3-Cu, depending on the relative amounts of each sulphide in the mixture.

Jan 1, 1940

The properties required for a com-pound to form useful thermoelectric materials are described. Uranium compounds which might have these properties are reviewed. Several of these compounds have been prepared and fabricated into compacts. The apparatus used for hot pressing, and for the measurement of thermoelectric power, electrical conductivity and thermal conductivity, is described. Detailed attention has been given to the properties of the nitrides. Preliminary studies on a number of other uranium compounds are reported. The figures of merit of the best materials so far examined are one-tenth of those necessary for a useful thermo-electric material. THE efficiency of thermoelectric materials for power generation and cooling is determined by their figure of merit, Z = a2 a/K, where a, a and K are thermoelectric power, electrical conductivity and thermal conductivity, respectively. It is well known that the largest values of Z are achieved with semiconductors (1). High mobility of charge carriers is necessary for simultaneously high thermoelectric power and electrical conductivity.The properties required for a com-pound to form useful thermoelectric materials are described. Uranium compounds which might have these properties are reviewed. Several of these compounds have been prepared and fabricated into compacts. The apparatus used for hot pressing, and for the measurement of thermoelectric power, electrical conductivity and thermal conductivity, is described. Detailed attention has been given to the properties of the nitrides. Preliminary studies on a number of other uranium compounds are reported. The figures of merit of the best materials so far examined are one-tenth of those necessary for a useful thermo-electric material. THE efficiency of thermoelectric materials for power generation and cooling is determined by their figure of merit, Z = a2 a/K, where a, a and K are thermoelectric power, electrical conductivity and thermal conductivity, respectively. It is well known that the largest values of Z are achieved with semiconductors (1). High mobility of charge carriers is necessary for simultaneously high thermoelectric power and electrical conductivity.

Jan 1, 1963

By Guangdong Institute of Resources Comprehensive Utilization, Y. H. Tang, H. X. Hu, T. S. Dong, Z. H. Zhang

"A world class rare metals ore deposit in Africa belongs to a massive granite type poly-metallic pyrochlore-niobium resource. Successful project development in realizing the resource is vital to Africa’s economy and pyrochlore processing technology.The ore properties are quite complex due to the presence of varieties of valuable minerals, fine dissemination and intimate association of minerals and the relative abundance of easy-floatable minerals. The separation of pyrochlore from zircon, calcite and mica is generally considered difficult. Whilst studies have previously been conducted by several independent institutions overseas, no satisfactory process has yet been developed to date for the ore deposit—possibly due to the process designed being too complex; high cost of regents; lower performance.Based on process mineralogy study and extensive testwork, the authors have in recent years developed a new technology—“De-slime—Iron-rejection—Zircon (with calcite) and Calcite reverse flotation—Pyrochlore flotation”. The flow-sheet is characterized by ?1prior removal of slimes and iron minerals; ?2 Zircon (with calcite) and Calcite reverse flotation; and ?3Pyrochlore flotation applying new type of chelating collector GYX3 developed by GZRINM in conjunction with selected regulators and depressants.The process involved in the new technology is simple to implement and facilitates stable operation; the flotation reagent regime is easily adaptable; the cost of main reagent is lower largely because it is easy to manufacture and is environmental friendly. Laboratory test results demonstrated that, for raw ore assaying 0.35% Nb2O5, 0.03% Ta2O5 and 0.45% ZrO2, pyrochlore concentrate grade of >35% Nb2O5 could be obtained with >74% recovery. Meanwhile, the Ta2O5 content in pyrochlore concentrate could be recycled, and ZrO2 recovery >50% could be achieved in zircon concentrate assaying ZrO2>63%—significantly improving the technical-economic indicator. These results were verified in pilot trials of 1.44t/d throughput. The paper presents the new technology in whole, summarizes the key factors affecting its performance and discusses in simple terms the mechanism of separation."

Jan 1, 2016

By D. K. Matlock, D. J. Hamre, J. G. Speer

Ultrafine ferrite (UFF) grains may be produced in surface layers of plate steels using controlled intermediate cooling followed by deformation. Experiments were conducted using a 0.12 C - 1.26 Mn steel on a Gleeble 1500 hot deformation simulator. Taguchi designed experiments were used to evaluate prior austenite grain size, intermediate cooling rate, intermediate cooling temperature, intermediate hold time and amount of reduction in order to observe the effects of variables and their interactions on the final microstructure while minimizing the number of required test runs. Evaluation of resulting microstructures and mechanical properties revealed a preferred thermal and mechanical history for developing ultrafine microstructures in surface layers of plate steels. Application of the fundamental concepts of phase transformations to industrial plate rolling is considered.

Jan 1, 2004

By Alain Simard, Sylvain Lacroix, Louis-Martin Dubé, Pierre Pilote

"The Harricana-Turgeon belt (HTB) is a poorly known volcano sedimentary belt in the NW part of the Abitibi Sub-province; it includes the Matagami, Joutel, Brouillan and Casa-Berardi mining districts. The HTB is dominated by volcanic rocks, which covers 65% of its surface area, followed by sedimentary (18%) and plutonic (17%) rocks. It is also transected by numerous deformation zones located either at the contacts of volcano-sedimentary units and granitoid bodies or cross-cutting them. A preliminary geological synthesis shows that mineral deposits are associated with certain regional geologic elements.The volcano-sedimentary units are grouped here into twelve band-shaped lithotectonic domains, most of which extend for more than 150 km E-Win the HTB. Each domain is defined by lithologies and facies associations, and gradiometric and electromagnetic signatures.Eight domains are composed of basaltic or basaltic to komatiitic associations, interlayered with thin pelagic sediments, representing sub-marine lava plains. Two domains are composed of basaltic to rhyolitic associations that are interpreted as volcanic arcs formed by one or several central volcanic complexes.The sedimentary rocks are grouped into two lithotectonic domains. Each is composed of rhythmic sequences of turbiditic sandstone- siltstone-shale, Algoma-type banded iron formations and conglomerates bearing plutonic and volcanic pebbles. These three facies come partly from mass flow at the bottom of a slope in a moderately deep marine environment. In each domain, a conglomerate sandstone- siltstone sequence, containing poly genetic pebbles of local provenance, is similar to Timiskaming-type alluvial deposits.The nineteen granitoids, found within the HTB and at its border, belong to numerous petrographic suites, and have been grouped into four structural families: pre-tectonic, pre- to early-tectonic, syn- to late-tectonic, and late- to post- tectonic. The pre- to early-tectonic plutons are presumed to be sub-volcanic and are generaly associated with the volcanism of central complexes.The HTB mineral resources consist essentially of polymetallic (Cu-Zn-Ag-Au) and gold (Au-Ag) deposits. The polymetallic deposits are located exclusively in the two lithotectonic domains composed of basaltic to rhyolitic associations (Matagami-Brouillan and Joutel Raymond). All gold deposits are associated with deformation zones superimposed on lithotectonic domain contacts and highlighted by graphitic units. Most of the deposits are hosted in the Casa-Berardi and Douay deformationzones, located at the contact of the Cartwright basaltic to komatiitic domain and the Taibi sedimentary domain"

Jan 1, 1990

By L. E. Djingheuzian

"IntroductionDURING the past two decades an enormous amount of empirical data has been accumulating on grinding. These data have been obtained by mill operators on grinding ores with a diversity of characteristics, and generally they have been published. However, whenever an operator, who has started milling on a new ore, has tried to find a case in literature which would exactly fit his particular grinding problem, he has failed. Evidently, something fundamental has been lacking in all these empirical data, and, as a consequence, each new operator has had to undertake his own experimenting, get the best results he can, maybe publish these results, and let it go at that. This, in the writer's opinion, has been• due to the fact that even the ablest and most inquisitive millman has been forced to look on grinding as an art, and so, except very rarely, has not been able to find the time to stop and think; if he did so, it was rather in a philosophic way, that grinding is a fundamental process, a process that takes place in river beds, on the sea shore, etc.Nevertheless, when all the data so far published are correlated and examined as a whole, one is struck with the advances that have been made in grinding. The writer (7) had made such a study in 1949, and, when the correlation was completed, it showed that there was nothing heterogeneous about the accumulated data and that when brought together they were in harmony with each other. The writer's conclusion was that, if grinding criteria were defined and were expressed in such a way as to make integration of any data into basic formulae possible, grinding would be established as a mathematically exact science, and grinding worries of the harassed mill operator would be at an end!The first attempts to rationalize comminution were made by Rittinger and Kick. However, their theories led to endless disputes which did not accomplish much, except possibly clearing the path for subsequent investigators."

Jan 1, 1952

By C. Nikolic

A process utilizing ozone for the precipitation of cobalt from nickel sulphate liquors containing ammonium sulphate has been developed. Best results were obtained using nickel carbonate to maintain solution pH at 5.0 to 5.5. Work was performed both in column and stirred-tank reactors. Variables studied included neutralizer type and concentration, NH4+ concentration, temperature, Ni++ and Co++ concentration, per cent O3 in the O2 carrier gas, O3 input rate and agitation. The over-all rate of cobalt rejection increased sharply with increasing agitation and ozone concentration in the gas phase, reflecting relatively slow transfer of ozone from the gas to the liquid phase.

Jan 1, 1978

By A. J. Monhemius

This paper reviews the history of modern iron-control processes in hydrometallurgy. Attention is paid to processes developed in the electrolytic zinc industry for removal of iron from zinc sulfate leach liquors and the problems faced by the industry in the safe disposal of the iron residues produced by these processes. Past lessons learned are projected onto current efforts to develop hydrometallurgical processes for treatment of copper sulfide concentrates. It is argued that any attempt to create a \u201chydrometallurgical copper smelter\u201d will fail, unless methods are developed that can recover iron in a form that can be directly used by the steel or pigment industries.

Jan 1, 2017

By G. McIsaac

"This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development, and mining method. Based on practical considerations, maximum rates are set for each zone’s development and production capacity. For the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum daily development capacity is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Also, the fixed cost of operating the mine is taken into consideration whenever mining activities take place.Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analyzed. “Whatif” scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan."

Jan 1, 2005

Mirador - Overview ? Located in Andean foothills of SE Ecuador ? Copper-gold porphyry hosted by calc-alkaline Late Jurassic granitic and porphyritic rocks ? 438 MT of 0.61% Cu and 0.19 g/t Au measured and indicated resources (at 0.4% Cu cut-off) ? Additional inferred resources of 235 MT of 0.52% Cu and 0.17 g/t Au ? Initial 25,000 tonnes/day production, expanding to 50,000 in year 6 320 MT of 0.62% Cu, 0.2 g/t Au ore mined at an average 1.4:1 strip ratio over a 21 year mine-life

May 1, 2006

By Ben Habermann

"The object of the work described in this paper was to increase the understanding of the relation that capillary pressure of a rock, hydro-dynamics, and accumulation of oil in stratigraphie traps have to one an-other. The hydrodynamic oil-water tilt equation is derived by considering the two vector gradients involved: (1) buoyancy of oil in water and (2) hydraulic gradient.Recent theories show the necessity for oil to have a continuons phase in the reservoir rock in order to mi-grate; this fact applies to hydro-static as well as to hydrodynamic conditions. Hydrostatically, the displacement pressure of the rock deter-mines the amount of oil that can be trapped behind a permeability barrier. If the buoyancy of oil in water exceeds the displacement pressure, oil will migrate up-dip; an oil trap will be formed where displacement pressure is greater.In stratigraphie traps the pressure drop caused by moving water is positive when its direction is down-dip, helping accumulation; and it is negative when its direction is up-dip, forcing the oil into the tighter section of the reservoir. Theoretically, pro-vided we have data such as: (1) the displacement pressure of an up-dip permeability pinchout, (2) density difference between the oil and water in place, and (3) the direction and magnitude of the hydrodynamic gradient (if any), the possible extent of a stratigraphie oil accumulation down-dip can be predicted.To test the above theory sample cores from three wells in the Denver Basin were analyzed and the oil column that could be held under hydro-static conditions was calculated. After the hydrodynamic influence was considered, the results were compared with actual field data.The significant fact shown by this investigation is that the calculated oil column in one reservoir very closely approximates the actual extent of the oil column in a well. Also in accordance with the theory, the capillary pressure caused by the buoyancy of the oil column exceeded the measured displacement pressure on core samples from another productive field. For very tight shaly sand and questionable oil shows, the interpretation of data is very critical, as shown by experiments on core samples from a third field."

Jan 1, 1960

By F. Habashi

"A short account will be presented on the extraction of rare earths from monazite sand, bastnasite ore, and phosphate rock of igneous origin. This includes mineral beneficiation, leaching methods, fractional crystallization [of historical interest], ion exchange, solvent extraction, precipitation from solution, and reduction to metals. INTRODUCTIONOriginally, the term rare earths was only used for the oxides, R2O3, which are similar to one other in their chemical and physical properties and are therefore difficult to separate. Within the rare earth group, the elements scandium, yttrium, and lanthanum differ in their atomic structure from the elements cerium to lutetium (the lanthanides, Ln). Scandium occupies a special position with respect to this classification and its other properties, and therefore does not belong to either of these groups. The rare earth elements always occur in nature in association with each other. The isolation of groups of rare earth elements or of individual elements requires costly separation and fractionation processes owing to the great similarity of the chemical and physical properties of their compounds, which explains why the history of their discovery has extended over such a long period.The word “rare”, when used to describe this group of elements, originates from the fact it was thought that these elements could only be isolated from very rare minerals. Considering their abundance in the Earth’s crust, the term rare is now inappropriate. These elements are lithophilic and are therefore concentrated in oxidic compounds such as carbonates, silicates, titano-tantalo-niobates, and phosphates.The abundance of the rare earth elements taken together is quite considerable. Cerium, the most common rare earth, is more abundant than cobalt. Yttrium is more abundant than lead, whereas Lu and Tm are as abundant as Sb, Hg, Bi, and Ag. For all practical purposes promethium does not occur in nature. It forms only in nuclear reactors."

Jan 1, 2012

By A. Ignatieff

This is the first in a series of Coal Technology Reviews being prepared in accordance with a recommendation voted by the Coal Division in session at the Jubilee Meeting, Vancouver, April, 1948, that the Department of Mines and Resources be requested to arrange for publication by the proper Government authority of a Quarterly Review&apos; of Coal Technology, for distribution among those concerned in the production and use of coal in Canada. This recommendation was subsequently endorsed both by the Council of the Institute and by the Dominion Coal Board. Further reviews (or digests) will appear at intervals in the Bulletin, or will be published and distributed by the Board which, meanwhile, has undertaken to distribute reprints of Mr. Ignatieff&apos;s review.-En. * * * The fields in coal mining technology which are considered to demand most attention and study at the present time are reviewed under the headings appearing below. Mechanization In the light of the growing shortage of skilled miners and the necessity of mitigating constantly increasing mining costs, interest continues to centre in mining methods and applications of mechanization chat will produce the maximum reduction of man power. The growth of strip or open-cut mining, also, is a consequence of this trend. Mechanization at the face attracts most attention and the trend is toward developing and adopting machines capable of cutting and loading the coal in one operation instead of having the separate operations of cutting, drilling, blasting, and loading. In Great Britain, where longwall mining is? the general practice, the A.B. Meco-Moore machine still receives much attention, and accounts describing its performance over reasonably long periods have appeared in the technical press.

Jan 1, 1948

By George Delorme

"AbstractThe basic intention of this paper is to present, from a practical viewpoint, a thorough outline of all the sound and accepted principles connected with attaining satisfactory rope performance from multi-rope friction winders.In order to emphasize the importance of some aspects of rope maintenance, a limited amount of hoist rope theory has been included, a s it is felt that without this, some of the more critical, but nevertheless practical, aspects would perhaps pass without full appreciation of their individual merit.It is very much appreciated that many of the maintenance topics and practices discussed herein are already being observed with a high degree of skill among those already involved in modern friction winding. The hope is expressed, however, that the paper will be of additional assistance, and of particular help in introducing sound maintenance principles to those who are moving into this field of operation for the first time.Hoist RopesWITH a multi-rope friction winder system, structural upset within the hoist rope's cross section can occur if the ropes slip in the drum treads. This upset will usually appear at either end of the rope at the tangent point of the drum or deflection sheave with the respective conveyance in the normal uppermost position. This slipping action on the drum causes the outer cover of a Full Locked Coil or the strands of a stranded rope to shift, leading to structural upset. The result very often means that the ropes have to be withdrawn from service before completing their maximum service potential.The cause of any rope slipping in its tread can be associated with a discrepancy in tension of that rope between one side of the drum and the other."

Jan 1, 1977

By Norman Marr

Introduction In Canada, the mining industry and water-power development are intimately associated in that mining, which ranks second among the country&apos;s primary industries, depends principally upon hydro-electric energy for its large power requirements. On the whole, the Dominion has been very favourably endowed with water-power resources; generally speaking it is a well-watered country with numerous rivers and lakes located in are as where the topography favours water-power development. Precipitation, the raw material of water power, varies from an annual fall of more than l00 inches on the Pacific coast to about 12 inches in sections of the Prairies and the Northwest Territories; in Ontario and Quebec the annual average is 24 to 40 inches and in Nova Scotia about 45 inches. In its descent to the sea, the resulting run-off, much of it from considerable altitudes, creates sources of potential energy at every rapid and fall along the country&apos;s many streams and rivers. Many of the innumerable lakes in the Dominion provide storage basins for the regulation of stream flow, thus enhancing the potential power of available sites. While water-power resources are fairly well distributed across the Dominion, as is shown on the accompanying map of Canada showing power sites (Figure 1), it is particularly fortunate that those areas which are lacking in indigenous fuels have been compensated in large degree for this scarcity by being favoured with a high proportion of the total potential water power. This has an important bearing on the mining industry in that extensive mining operations can be economically carried out in the great Canadian Shield, which is lacking in commercial coal deposits but is rich in water-power resources. This Precambrian formation, which forms a wide belt around Hudson bay and in which many metalliferous ores are found, was &apos;subject to severe glaciation in a recent geological period, so that its river systems are comparatively young and are characterized by numerous lakes joined by short reaches of fast water, rapids, and falls which offer frequent opportunities for power development. The western Cordilleran region, which also is important in mining, has abundant water power. The accompanying geological map (Figure 2), prepared by the Geological Survey of Canada, shows the great extent of the Precambrian and Cordilleran regions and may be compared with the map of water-power sites to show the high incidence of water-power resources in these potential mining areas in which important mineral discoveries have already been made.

Jan 1, 1949

By Jas. G. Ross

Introduction Asbestos, a mineral known and used in ancient times, has become an article of commerce only during the life of the older asbestos miners in Quebec. The diversified uses of this adaptable substance are now numbered by the hundreds. Wherever insulation or resistance to heat may be required, asbestos, either by itself or mixed with some other material, may be employed to advantage. Regarded as a curiosity for centuries, it is now in such common use that it is familiar to all. The demand for long fibre for use in the manufacture of textiles and brake-lining, and for shorter fibre for making shingles, paper, and insulation materials, serves to support the industry of mining asbestos-bearing rock and milling the fibre from it in Canada, South Africa, Russia, Cyprus, and the United States. The commercial use of asbestos dates only from 1876, in which year large deposits were discovered in the Province of Quebec, Canada. Prior to that year a small amount of long fibre amphibole asbestos was produced in Italy. Occurrence In Canada In the Eastern Townships of Quebec, along the line of the Quebec Central railway, is an area of serpentine rock. It extends westerly into Vermont and easterly to Gaspe. A part of it, the section from Danville to East Broughton, contains areas in which occur deposits of commercial asbestos fibre of the chrysotile variety. Pits have been opened on some of these deposits at Danville, Coleraine, Black Lake, Thetford Mines, Robertson, and East Broughton. Thetford is distant 68 miles from Quebec city, East Broughton lies 25 miles to the northeast of Thetford, while Danville is 45 miles to the southwest of Thetford.

Jan 1, 1927