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By E. L. Martheleur

The use of electricity in coal mines dates almost from the time when it was realized chat it could be used to produce mechanical power. The first motor put in service underground was installed to drive a small pump nearly 40 years ago, and since then the use of electricity in mines has reached an extent undreamed of at that time. We now find its universal adoption in all the mining countries of the world. Great progress has been made in the development of mining electrical apparatus in the last decade, and excellent and adequate material is now available for the use of electricity underground. Although mining accidents, due to the use of electricity, are not frequent, the miner is justified in demanding chat all electrical apparatus for installation below ground be constructed with a greater degree of safety than that used on the surface. That this view is shared by the authorities of the different mining countries is evidenced by governmental regulations relative to the use, erection, and maintenance of electrical apparatus below ground. Those with which we are specially concerned are the regulations for the installation and use of electricity in the coal mines of Nova Scotia. The potential dangers of electricity in coal mines are: Shock or burns by contact from live parts. Shock or burns by contact with parts which, although normally dead, have become accidentally alive. Fire. Explosion of gas or coal-dust Explosion of apparatus.

Jan 1, 1928

By Robert E. Loftus

"The author discusses the growth in the use of ocean-going bulk carriers for the transportation of mineral commodities, and predicts future trends. The various types of tonnage carriers are described, along with the special discharging gear used, the costs involved and the duties of some of the personnel.THE FIRST CONSIDERATION in planning the ocean transportation of minerals is the type of vessel to be utilized. The modern 'Bulk Carrier' bas proved to be the most successful vehicle for the purpose. I would there-fore like to describe this fleet in some detail and at-tempt to show the impact that the bulk carrier bas bad on the movement of bulk materials."

Jan 1, 1968

By F. Sorenson, P. A. Castellarini, F. Garbarino, M. N. Garcia

"Recently, significant efforts to improve productivity from the tight intervals of the Mulichinco Formation within the Sierra Chata Field in the Neuquén Basin have been ongoing. Because conventional high quality reservoirs were being developed in this field, a proper reservoir understanding and completion approach was applied. After developing these high permeability reservoirs, the operator began evaluating the tight intervals and new areas within the field, but a completely different approach was necessary to achieve motivating production improvement.An extensive study to help enhance reservoir understanding and identify key factors controlling productivity of these tight intervals (which tend to be in the range of 5 µD) has been ongoing. Some of the issues discussed in this study are 1) petrophysical review, 2) rock properties calibration, 3) geomechanics understanding, 4) faulting and micro faulting/lineaments description, 5) stimulation and completions review and, 6) understanding key production drivers.As in many other tight reservoir projects, a considerable area of the reservoir must be effectively stimulated during the hydraulic fracturing process to achieve economic productivity. Two critical issues hinder these objectives. First, the low permeability in addition to a pore pressure close to or even lower than hydrostatic are critical characteristics when attempting to flow back the well and clean up fractures. Second, very high horizontal stress anisotropy resulting from a strike slip stress regime promotes the generation of simple planar bi-wing fractures. It is well-known that this fracture geometry will contact much less reservoir area compared to more complex fractures, as the operator would normally intend to create at very low permeability reservoirs.This paper discusses these issues and how they were addressed. A pilot drilling and completion program was initiated during 2012 to validate this study. Key factors include well location relative to formation unconformities, their orientation relative to the far field principal stresses, hydraulic fractures generated, and overall completion design."

Jan 1, 2015

By B. Tougas

Recycling of titanium represents an important economic activity due to high cost of the material and the amount of returns of machined parts which represent the bulk of finished titanium products (typical "buy to fly" of 10 in the aeronautic industry). In the present work, the metallurgical quality of 76 mm in diameter and 20 cm ingots poured in coated graphite mold will be assessed against the nature and condition of application of 4 coatings namely aluminum oxide, yttrium oxide, zirconium oxide and zirconium oxide with 4% aluminum oxide. The metallurgical quality has been evaluated in terms of alpha case thickness, microstructure and composition. Microhardness from surface will be assessed against casting conditions. Least square regression analysis have been use to optimize casting conditions.

Jan 1, 2011

By P. Hansman

"Place Dome Canada's Detour Lake Mine is a low-grade gold producer located in northeastern Ontario. Production is targeted for 2850 tonnes of ore per day. As reserves and mining areas continued to be found below and far to the west of the shaft (Fig. 1), it became necessary to review and upgrade the materials handling facilities. This paper deals with the selection, design and construction of an underground crusher and conveyor system capable of handling up to 450 tonnes per hour from the lowest existing level in the mine.BackgroundThe Detour Lake mine site is accessed via secondary Highway 652 which runs northeast out of Cochrane, Ontario. The road consists of 200 Ian of hard top followed by 100 Ian of well maintained gravel to the mine site. A 1500 m airstrip is maintained at the mine site for emergency use. Prior to 1991, the workforce was flown to and from the mine site. Crews were now bused to the site from Timmins. Remnants of a winter road exist to the southeast which at one time ended in La Sarre, Quebec. This was the route used to haul bulk items during the construction period and early production years.A town site has not been established at the site for the current operations. Instead, a rotational scheme is being utilized whereby most personnel will work seven days on site followed by seven days off site. For some employees, however, the work week is termed as a four/three schedule where they work 42 hours between Monday at 10:00 a.m. and Thursday at 4:00 p.m. with the following three days off. All surface employees and maintenance employees underground work 12-hour shifts. All underground employees work a lOV2-hour shift. Supervisors work a similar schedule as their crews, however, other staff may overlap their rotation during the week.A five-compartment shaft was sunk in 1984 from surface to the 610 m elevation. Shaft stations were established at the 120 m, 260 m, 360 m, 460 m, and 560 m levels. The cage compartment consists of a single deck, 4O-man cage in balance with a counterweight. The cage hoist is an Ingersoll-Rand 10H and is regulated to travel at 4.1 m/s. Two 9 t skips operate in balance at a travel speed of 7.1 mls. The skip hoist is a 3.05 m drum Nordberg. Both hoists are automated to function without a hoistman during normal skipping and cage service runs."

Jan 1, 1995

By H. C. Gunning

SOME small vanadium-bearing deposits on the west coast of British Columbia about 100 miles north of Vancouver are of interest for several reasons. They are of a type that is, so far as we know, unique. They are difficult to identify as being vanadiferous so that, unless they are described, other similar deposits could easily pass unrecognized. Furthermore, although none of them has as yet been proven to be of commercial proportions, no good reason is apparent why larger, and therefore valuable, deposits should not occur under similar geological conditions. The original discovery on Quadra island was made in 1932 and has been recorded by H. V. Ellsworth and H. C. Gunning (l). Since 1932, prospecting in the area has revealed other similar deposits, one about a mile south of the original and another some ten miles to the east, near Menzies bay on Vancouver island. The Quadra Island showings are a mile and a half north of the head of Gowland harbour, a small inlet that is easily reached by gas boat from Campbell river, about four miles to the southeast on Vancouver island. The deposits were examined by the writers in the spring of 1943 in connection with field work sponsored by the Department of Geology, University of British Columbia. We are indebted to Mr. G. A. Dirom and Mr. Lothrop, of Vancouver, for helpful data on the Menzies Bay deposits, and to Dr. V. Dolmage for making a brief trip to Gowland harbour and discussing the deposits.

Jan 1, 1944

By Z. B. Karshigina, Ye. G. Bochevskaya, E. A. Sargelova, Z. S. Abisheva

At the present time of depletion of reserves of high grade rare earth deposits, it has become necessary to involve low grade raw materials in the production. Among the rare-earth deposits in Kazakhstan, the most advanced one is Kundybai. The mineralogical composition of ore is represented by the minerals: a-quartz SiO2, kaolinite Al2(Si2O5)(OH)4, muscovite KAl2(AlSi3)O10(OH, F)2, albite Na(AlSi3O8), rutile TiO2, and hematite Fe2O3. It contains: 59.1–68.5% SiO2, 19.1–28.4% Al2O3, 7.2–10.3% Fe2O3, 0.51–0.84% TiO2, 0.10–2.32% CaO, 0.39–2.10% MgO, and some other elements. Rare earths are located in the clay part (kaolinite, goethite) in the ion-adsorbing form, and they are represented by the main ore mineral churchite - YPO4·2H2O. In the ore the amount of rare-earth elements (total REEs) varies from 210 to 600 ppm. Elements of the cerium group predominate (La, Nd, Ce, Sm, Pr) and the yttrium group is represented by Y, Gd and Dy. Extremely thin intergrowth and accumulation of REEs in clay minerals cause difficulties in their recovery using flotation and gravitation beneficiating methods. The purpose of this work is the development of an extraction method for the main mineral components of ore with transfer of the total REEs into the solution with high extractive efficiency. Results of the experimental work into high-temperature processing (hereinafter referred to as sulphatization) of ore by sulphuric acid with subsequent dual-mode water leaching of the sulphate product (sinter) are presented in this manuscript. The influence on the ore sulphatization process of some physical and chemical parameters: liquid-to-solid (L/S) ratio (0.36–0.86 cm3/g), temperature (100 – 500°?), concentration of sulphuric acid (3.0–18.62 mol/L) and duration (0.5–2.5 h) was studied. Optimal technological parameters of the process were determined to be: L/S ratio 0.36–0.46 cm3/g; temperature 500°?; concentration of H2SO4 9.0 mol/L; soaking time 1.5 h. Under these conditions it is possible to obtain extractions of ~ 85% REE, as well as 58% aluminium and 10% iron. XRD and IR-spectroscopy analyses were used to determine the material constitution of sulphated cakes obtained under optimal conditions. It was found that the primary minerals are quartz and muscovite; however different sodium aluminium silicates and albite minerals are present as well. In the future, it is proposed that the leach residue cakes are processed into precipitated silica (“white soot”).

Jan 1, 2016

By I. R. Jonasson, R. W. Boyle

"Current interest in the distribution of mercury in the natural environment comes from quite different, though not unrelated, sources. Mercury has long been an important metal in many industries and has, therefore, been much sought after by mining interests. The presence of mercury traces in the various media of the natural environment, namely soil, rock, air, water and vegetation, is exploited by geochemists not only to find mercury and polymetallic ore deposits, but also to find most other types of economic metal mineralization. More recently, however, mercury has caught the attention of health authorities and environmental scientists who are becoming increasingly concerned over the hazards of mercury wastes and the danger these present to the environment and to man. It is now apparent that the trace quantities of mercury, considered so important and helpful to exploration geologists, can be concentrated in the biosphere to such levels as to present considerable problems for ecologists. This article summarizes most of the available data on mercury contents in materials of geological interest and presents average normal values for rocks, ores, minerals, soils, sediments, waters and plants. The geoch.emical cycle for mercury in nature is presented and the mechanisms of mercury migration around the cycle are discussed."

Jan 1, 1972

By J. L. Thornton

Introduction The importance of coal in our economy is well established, but it may not .be so generally realized how important a part it plays in our daily life. Select a product - any product - and, if it is made in America, bituminous coal has touched it first. Everywhere we will find coal, derivatives of coal, or functions made possible by coal. Apart from the well known major uses of coal for domestic purposes, coking, utilities, railways, and manufacture of steel and cement, there are over 200,000 products derived from coal, from lipstick colours to nylon products and perfumes. An item of interest is the recent action of the Canadian Government in voting $90,000 for development of coal deposits in Yukon Territory to make coal available to the settlers in that area. The value of this move, in case of some emergency, is very evident. Coal in its several stages of formation as peat, lignite, sub-bituminous, bituminous, semi-bituminous, semi-anthracite, and anthracite, has been used for centuries. Coal, as such, was not very well known to the ancients. First reference to "magic stone', or coal, was in 371 BC by Theophrastus, a pupil of Aristotle. This substance was said to burn like wood coal or charcoal and was used by the smiths. The first record we have in modern times was in 852 AD, when sea coal was gathered by the cowled monks of Durham, in Britain, and even at that time a major problem was transportation. Our first record of coal in this continent was near Richmond, Virginia, in 1700. Commercial mining was not under way, however, until 1750. The anthracite fields (presumably in Pennsylvania) were opened in 1793. Even so, there was no extensive mining until about the year 1820. The famous Pocahontas coalfields were opened in 1883. The earliest record of coal mining in Canada is about 1746.

Jan 1, 1950

By J. Oyunaa, P. Munkhbaatar, A. Sarnai

"The molybdenum mining process used at Mongolia Erdenet Company is a selective flotation of molybdenite from the copper porphyry ores in which the extraction of molybdenum comes as a byproduct of the ongoing copper production.The mineralogical composition of molybdenum concentrate is 99.4% molybdenite (MoS2), 0.09% molybdenum oxide (MoO3), 0.52% powellite (CaMoO4) and wulfenite (PbMoO4) and content 47.76– 47.92% molybdenum, 1.5–2.67% copper, 0.04% renium.From compared solvents sodium and carbonate and ammonia are like extracted molybdenum than hydrochloric acid, which contained 96.23–97.72 p.c. of its total amount. Hence to take into consideration abundance, cheap and suitable for analysis and processing the molybdenum concentrate ammonia is choosing as a basic solvent. By direct evaporation of ammonia extract solution, we obtained ammonium ortomolybdate, which contains 73.47% MoO3. INTRODUCTIONMolybdenum occurs in the earth’s crust in an abundance of about 10–14%, mainly as molybdenite, MoS2. Small quantities are also associated with other metals having similar chemical properties. Thus wulfenite (PbMoO4) is found in oxidized parts of sulfidic lead deposits in many regions of the world; powellite [Ca(Mo,W)O4] is a calcium molybdate usually formed from the modification of molybdenite in deposits containing tungsten as scheelite (CaWO4) and tungsten substitutes for molybdenum up to about 10%. Ferrimolybdite (Fe2Mo3O12·8H2O) is the product of oxidation of molybdenite in the presence of iron (III) compounds. Molybdenite is the primary source of molybdenum. Should demand for molybdenum rise so that additional sources become necessary, wulfenite, powellite, and ferrimolybdite may become commercially significant. Molybdenum ore is mined by underground and open-pit methods. A typical primary molybdenum ore body contains 0.05–0.25% Mo, and secondary ore bodies (copper porphyry ores) average 0.3–1.6% Cu and 0.01–0.05% Mo. Flotation remains the preferred and almost exclusive method of upgrading the molybdenite mineral to an industrial-grade molybdenite concentrate containing 90–95% MoS2, the balance being gangue (Habashi, 1997)."

Jan 1, 2016

"THE GOLD MINING REGION of Timmins - Val d'Or, astride the Ontario-Quebec border, has long suffered the effects of rising costs during the period when the U.S. price of gold was fixed at $35 per ounce. The federal government, through such assistance programs as that set up under the Emergency Gold Mining Assistance Act (E.G.M.A. ) in 1948, has subsidized the gold mining communities of Canada for a total of over $300 million to March 31, 1972. Of this, the Timmins - Val d'Or ""gold belt"" has received more than twothirds, almost $220 million. In spite of these continuous subsidies, only 12 gold mines are still producing in the Timmins - Val d'Or belt, whereas 71 mines have received subsidies for some period since 1948. The vital question is how the communities previously supported principally by the mining of gold will survive in the long run, as many of the older mines either are already depleted or are quickly becoming so. With the rising price of gold on the 'free market in recent months, prospects look a little brighter for the time being. Even with the increased official price of U.S. $38, which made the maximum government subsidized price about $48 per ounce, gold mines have not sold any gold to the government since January 1972 and some stopped doing so months before that. The populace of the region has not been enthusiastic about relocation nor about extensive retraining programs in the past and probably will not be in the future. So, when the remaining gold mines become depleted, the old problems of community depression will remain."

Jan 1, 1973

By M. H. Cullender

THE determination of the flow characteristics of gas wells depends upon the analysis of pressure data obtained under shut-in conditions and under one or more known flow conditions. These data are commonly referred to as back-pres-sure test data, and I know you are all familiar with the back-pressure equation where, Q rate of flow, Mcfd @ standard conditions C coefficient of the back-pres-sure curve P 1 formation pressure, psia P • sand face flowing pressure, psia P2 (psia)2/1000 n exponent of the back-pres-sure curve Figure 1 is a graphical presentation of the back-pressure equation; the coefficient is the rate of flow at a difference in squared pressures of 1, in this case 2250 Mcfd, and the exponent defines the manner in which the rate of flow changes with a change in the difference in squared pressures. In Figure 1, the exponent of the back-pressure curve is 0.554 which means that for a 10-fold change in the difference in squared pressures, there will be a 3.58-fold (10 raised to the 0.554 power) change in the rate of flow.

Jan 1, 1961

By Vladislava A. Ignatkina, Fillip O. Milovich, Vladimir A. Bocharov

"Complex research of flotation concentrates of monomineral fractions of chalcopyrite, sphalerite, galena, pyrite, pyrrhotite included methods of adsorption of collectors, surface compounds by IR ATR, and surface films of flotoreagents by TEM. They revealed that the proportion of the parts of thionocarbamate (TC) and dithiophosphate had an effect on the adsorption rate of the components of minerals, on the presence of characteristic bands, and, what is an important, visualized surface film of organic flotation reagents on the particles of concentrates by TEM. The predominance of thionocarbamate in a composition selectively increases the adsorption rate constant of the components and recovery of chalcopyrite compared with sphalerite and galena. The highest flotation rate using TC is characteristic for chalcopyrite (0.62 min- 1) in case of individual use, and it's in combination with butyl xanthate (25% butyl xanthate or 3:1) 0.89 min-1 too. We studied the ternary blend - dithiophosphate: thionocarbamates: butyl xanthate. The increase of the proportion of butyl xanthate in combination reduces the contrast of the flotation rate among all sulfides.Practice flotation of refractory sulfide copper-zinc ores of the Urals (content sulfide iron - 75- 95%) confirmed that the use of a combination of selective collectors increases selective recovery of copper sulfide minerals up to 50% at the first fraction that is the conditioned copper concentrate. New selective sulfhydryl collectors resulted in high levels of recovery of copper into a concentrate - more than 90% - against 70-72% (butyl xanthate) from copper-pyrite ore. Low floatability of iron sulfides has been obtained by selective sulfhydryl collectors. Using weak selective sulfhydryl collectors can reduce pH into collective or selective flotation from pH 10-10.5 to pH = 7.2-7.5, which improves the quality of individual concentrates of nonferrous metals and their recovery. The same is true for polymetalic sulfide ore. The volume of gold recovery also increased."

Jan 1, 2016

By Paul Guliov

Coal-bearing Tertiary sediments of the Ravenscrag Formation in southern Saskatchewan host numerous deposits of clinker resulting from in situ coal combustion. Clinker deposits form when sediments of relatively low temperature firing properties overlie coal seams which are undergoing prolonged spontaneous combustion. The resulting fired material is useful for decorative landscaping aggregate, rock gardens, driveways, mud control and others. Predicting the occurrence of clinker deposits requires a knowledge of the spatial distribution of coal seams and the nature ofoverlying sediments. Knowledge ofpaleotopography at the time of coal combustion can assist in locating more highly-fused material which can yield greater block sizes. Coal data bases can be used as a predictive tool by outlining areas where coal is or was at or near surface and therefore may have been susceptible to spontaneous combustion.

Jan 1, 2001

By Kenneth M. Haley

THE development of Reserve Mining Company's pelletizing practices began in 1949 in a pilot plant located at Ashland, Kentucky. Three years later the participating companies -Armco Steel Corporation, Cleveland Cliffs Iron Mining Company and Republic Steel Corporation concluded the work and the small plant was shut down. Oglebay Norton and Company was the operating manager and Armco Steel Corporation furnished labor and services. Arthur G. McKee and Company were the designers and constructors. The equipment flow sheet that was employed in that pilot operation is shown in Figure 1. This was Reserve's first step from the laboratory work per-formed by the Mines Experiment Station of the University of Minnesota in developing a commercial operation. The plant used New York state concentrate, purchased from Jones and Laughlin Steel Corporation's Benson Mine. This concentrate, minus 14 mesh, 64.3 per cent Fe, 5.7 per cent Si02, was processed at Ashland to 80 per cent minus 325 mesh in conventional ball mill, classifier, thickener, filtering

Jan 1, 1961

By G. S. Ospanova

The results of complex processing sulphide copper ore and advantages of recovery of copper by vat and heap leaching, sorption, cementation and electrolytic solutions processing and utilization of waste material after heap leaching of copper for production of building materials were investigated. The combined chemical solvents with the additives of oxidizing agents are developed at the KazNTU. The solvents are inorganic or organic chemical reagents, which form complexes of Cu, Au, Ag, Pt, Ni, Sr, Co etc. Recovery of non-ferrous metals from solutions and purification of industrial waste waters is carried out on the base of using new synthetic and natural sorbents (from local raw materials) which are able to bind ions in both cationic and anionic forms depending on type of ligands and external conditions. Optimum parameters of copper sorption were determined. The developed wasteless technologies of copper extraction from sulphide ores with usage of new non-toxic solvents and accessible sorbents with full recycling of water are tested in pilot scale heap leaching, and are recommended as the ecological, economical and practical alternative to traditional methods.

Jan 1, 2007

By C. Allen, V. Hensel, J. S. Stachulak

"Vale has been actively evaluating new technologies to curtail diesel emissions. This paper discusses the selection, installation, operation, and evaluation of the MANN+HUMMEL SMF®-AR diesel particulate filter system to reduce diesel particulate matter emissions in underground mines. The system uses a sintered metal filter element, an iron fuel-borne catalyst with an onboard dosing system, an electric heater that uses onboard power, and a sensor-based control unit. More than 6,000 h of testing demonstrated that the system represents a breakthrough in the successful control of soot emission from light-duty vehicles with differing soot emission levels, exhaust temperatures, and duty cycles.RÉSUMÉ La compagnie Vale évalue activement de nouvelles technologies pour réduire les émissions de diesel. Le présent article discute du choix, de l’installation, du fonctionnement et de l’évaluation du système MANN+HUMMEL SMFMD-AR de filtrage des particules de diesel pour réduire les émissions de particules de diesel dans les mines souterraines. Le système utilise un élément filtrant en métal fritté, un catalyseur à base de fer dans le carburant avec un système de dosage intégré, un élément de chauffage électrique qui utilise l’alimentation incorporée et une unité de contrôle avec un capteur. Plus de 6 000 heures d’essais ont démontré que le système représente une avancée pour réussir à contrôler les émissions de suie des véhicules légers avec différents niveaux d’émission de suie, différentes températures d’échappement et différents cycles opératoires."

Jan 1, 2015

By G. Deschênes

Located in North West Tanzania, Buzwagi is an underground narrow-vein gold mine owned by Barrick Gold. The plant was commissioned in 2000. The reserves are estimated to be more than 25 years. The ore, containing gold, silver and copper mineralization in sulphides, is processed at 3,300 tpd. This paper presents the results of an investigation to determine the performance of an ammonia-cyanide leaching approach to recover gold from two samples. Coarse gold was recovered by gravity prior to leaching. The gravity tailings had the following composition; 1.97 g/t Au and 0.31% copper for the medium cyanide soluble copper (MCSC) sample and 2.80 g/t Au and 0.53% Cu for the high cyanide soluble copper (HCSC) sample. Experiments were conducted for 72 hours in stirred tank reactors with monitoring and control of parameters. The straight cyanidation produced gold extractions of 76.1% for the MCSC sample and 84.6% for the HCSC sample. Associated cyanide additions were 6.1 kg/t and 11.5 kg/t respectively. The gold extraction of the MCSC sample was improved to 88.8% using 350 ppm NaCN and 700 ppm ammonia. The associated cyanide and ammonia additions were 2.5 kg/t and 1.7 kg/t respectively. For the HCSC sample, 82.5% gold extraction was obtained using 500 ppm NaCN and 600 ppm ammonia. The cyanide addition and ammonia additions were reduced to 3.8 kg/t and 1.0 kg/t respectively. No significant decrease in gold extraction was noticed when the cyanide and ammonia were reduced to 150 ppm and 500 ppm respectively. In the presence of ammonia, a significant amount of cyanide was oxidized to cyanate by the cupric ion. In the absence of ammonia, the formation of copper cyanide was the predominant reaction responsible for consumption of cyanide.

Jan 1, 2012

By Stopford Brunton

For many years it has been accepted as axiomatic that the greater number of 'veins' or 'leads' in the gold districts of Nova Scotia are of the 'interbedded' type. The corollary to this hypothesis is that the vein or lead will have a continuous hanging-wall of one kind of rock, and a continuous footwall of the same or another kind of rock; but the essential point is that the foot and hanging walls are, according to this theory, both continuous and of uniform composition throughout; and that the vein or lead conforms to the bedding of the adjacent strata. With regard to the deposition of the gold in the rocks, the probability is that the key of the problem is contained in a statement by E. R. Faribault, of the Geological Survey of Canada: "The combined effect of cleavage, jointing, and stratification is to cause the rocks, especially the quartzites, to break into rhombohedral blocks". It is essential to comprehend that the rocks of the Province are no doubt folded into anticlines and synclines; but also it must be fully realized that the gold deposits and pay-shoots do not depend so much upon these as upon the fractures resulting from the disturbance caused by the intrusion of granite masses, and controlled by the combined effect of cleavage, jointing, and stratification. These fractures would form the channels through which the ore-bearing vapours and solutions would rise, and at the junctions of these fractures, where the fracturing was greatest, the easiest passages would be afforded to the ore carriers, with the result that the ore-shoots would be found at or near the intersections of fractures. It is a significant fact that in at least thirteen different districts throughout the Province, operators have at various times remarked upon the occurrence of rich ore at the intersection of 'leads,' 'veins,' 'beds,' etc.

Jan 1, 1928

By D. A. Sloan

THE Young Davidson mine is of particular interest because of the extremely low costs and also because of the novel method devised for pillar recovery. The outstanding feature of the mining system is its simplicity and regularity. The successful operation of this property was de-finitely assured by the rise in price of gold in 1934. The mine is situated in the southeastern part of Powell township, about forty-five miles southeast of Timmins, Ontario. The local town, two miles distant, in Matachewan, which is twenty-five miles northwest of Elk Lake, the terminus of a branch line of the Temiskaming and Northern Ontario railway. Mining is confined to one of a group of five claims. The ore occurs in a body of syen.ite porphyry which is intruded along a contact of Timiskaming conglomerates with Keewatin altered ruffs and greenstones. This intrusion extends in a north-easterly direction from Davidson creek for 3,300 feet, of which length 700 feet lies within the Matachewan Consolidated property. The maximum width of the mass is 700 feet; it tapers off as it extends east-ward. The Orebody.-The syenite porphyry is of three types, probably all differentiates of the same magma, but only one of them is gold bearing. This is a cherry-red, coarsely crystalline type which forms the central part of the mass. It is more brittle and more fractured than the others, and consequently has allowed easier access to the gold-bearing solutions. The gold has been brought in by a branching system of quartz veins and along minute fractures. It is mainly in the form of very fine 'free' gold, but also occurs in pyrite, which is the chief metallic mineral.

Jan 1, 1942