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By P. C. Thurston, T. Setterfield, D. H. Watkinson

"The Maybrun copper deposit IS In a succession of pillowed basaltic flows in the Wabigoon sub-province, northwestern Ontario. The rocks have primary flow morphologies and remarkably well-preserved crystallization textures, including quench-textured plagioclase, in spite of metamorphism to the amphibolite facies. The sulphide assemblage chalcopyrite-pyrrhotite-cubanite with minor sphalerite and pyrite is primarily in interpillow spaces and is stratabound. Basaltic rocks immediately enclosing the copper sulphide minerals have an enrichment in Fe, Mg and K and depletion in Ca and Na relative to surrounding flows. The Maybrun deposit is interpreted to have formed contemporaneously with volcanism and alteration, and was subsequently metamorphosed with the enclosing basalts.IntroductionThe association o f significant base metal accumulations with mafic submarine flows in the Archean is as yet poorly documented. Such deposits, where noted, have typically been small, and are therefore commonly over looked. The Maybrun Mine, a 2.6 x 106-tonne copper deposit in pillowed basalt, has many similarities with large, well-documented volcanogenic deposits. Given the interpretation of the Maybrun Mine to be volcanogenic in origin, there is n o reason why similar processes could not produce large deposit s. This is an important realization in an area where Archean submarine mafic rock s are very common, but frequently are examined only superficially. As gold commonly occurs in deposits such as Maybrun, even modest-sized deposits may be economic. The basalts at Maybrun are remarkable for amphibolite-facies rocks because of their extremely well-preserved delicate volcanic textures, including quench textures.The Maybrun Mine is one kilometre south of Atikwa Lake, in the Wabigoon sub-province of the Superior structural province, 75 km southeast of Kenora, northwestern Ontario, at longitude 93°35'W, latitude 49°25'N (Davies, 1973). Archean metavolcanic and metasedimentary rocks and intrusions underlie the area. Goodwin (1970) concluded that the mafic and minor felsic metavolcanic rocks, as well as the overlying metasedimentary rock s, were an eastward extension of the lower cycle of the Keewatin type section for the Lake of the Woods area. He estimated that the stratigraphic thickness of Keewatin rock s in this area is about 6900 m, of which 87% is basalt. The flows contain numerous interlayered sills, predominantly of basaltic composition; they have been extensively folded, faulted, metamorphosed to amphibolite facies and intruded by numerous felsic bodies, most importantly the Atikwa Batholith."

Jan 1, 1983

By Ivor da Cunha

Ontario Mining Association (OMA) represents 57 members that are engaged in exploring, producing & processing mineral resources in an environmentally responsible manner. Conservation Bureau at the Ontario Power Authority (OPA) develops, coordinates and stimulates commitment to electricity conservation and demand management programs ? OMA selected compressed air optimization for high impact cost savings and energy efficiency potential ? Ontario Power Authority (OPA) provided $218k funding for $532k project ? Commenced summer 2006, Final Report June 2007 ? Three representative sites participating: ? Williams, CVRD Inco & FNX McCreedy ? Different levels of energy management ? Small, medium and large mining operations ? Different corporate practices and culture

May 1, 2007

By W. M. Goodwin

The gold district of northwestern Quebec, though it has attracted such widespread attention during the past year, is still in the prospect stage throughout, and one must preface any remarks about it with the plain statement that its capacity to produce gold commercially is still subject to proof. However, this proof may be forthcoming any day, and from widely separated localities. Consequently it is of interest to note some of the features of the region and of the prospects now being developed. First I shall note the relation of this mining development to the province of Quebec and to the Dominion; then will follow a brief resume of the known geological facts; and finally I shall describe briefly some of the more advanced prospects developed during the past twelve-month. Those that have followed closely the fortunes of the new gold-field will find little that is new in what follows, but it may serve a useful purpose for others by bringing together scattered items of information and presenting them as a whole. GOLD MINING AND AGRICULTURE First let us consider the gold belt in its relation to the province of Quebec. Apart from the world-renowned asbestos camp south of the St. Lawrence, it is the only mineral development of major importance the province has experienced. It is the first important development in the province's vast area of Precambrian rocks, most of which remains as yet totally unexplored and unprospected. The relative importance of this first mining camp in northern Quebec cannot as yet be gauged, but it is bound to stimulate an active interest in the other mineral-bearing areas now known to exist, and in the vast unexplored spaces.

Jan 1, 1924

By Mark Hollingworth

"There is general consensus that as the world continues to change at an ever-increasing pace, companies must continually adapt their operations in order to remain competitive. Those that change fast enough, survive; those that don’t, perish quickly. Today, we hear that it is not worth the time preparing corporate business plans as they are out-of-date before the ink is dry. Within the corporate environment of the 1990s, we must “think” strategically, be a “learning organization”, keep our costs low, focus on our core competencies, stay as flexible as possible and create value. So-called “sustainable competitive advantages” can be obsolete before a patent is issued — if its even worthwhile patenting the advancement. This is industry in the 1990s.Now, while all this radical change has been underway in the global industrial environment, what have Canada’s universities been doing to keep pace with the change affecting one of their major stakeholders? Have they adapted their products and services to suit the new market conditions? Have they built closer links to industry to try to understand how better to serve this important client? Do they welcome industry input as to how to redefine their mission, objectives, strategies or their course contents? Do their students graduate with skills ideally tailored for the global mining industry? In the era of communication, can they write high quality reports in English, never mind speak French or Spanish?In an effort to provide Canada’s engineering faculties with a “blueprint” for the future, the Canadian Academy of Engineering pre-pared a report entitled “Engineering Education in Canadian Universities”, published in August1993, which concluded with the following recommendations:"

Jan 1, 1996

By G. S. Hume

Research thrives on ideas, and the theoretical considerations of today are either the discarded notions or the proven facts of tomorrow. The progress made in the past fifty years in the acquisition of knowledge of petroleum geology is no less astounding than is the tremendous increase in the production of oil on the North American continent from 61 million barrels in 1897 to 1,917 million barrels in 1947, an increase of 3,300 per cent, with production of natural gas expanding from less than 400,000 Mcf in 1897 to approximately 4,500,000,000 Mcf, or an increase of 11,000 fold in the same period. In the search for and discovery of the oil and gas fields that have yielded such prolific wealth, no idea has had a more profound effect than has the ?anticlinal? theory of oil accumulation, propounded in 1844 by Sir William Logan, the founder of the Geological Survey of Canada, after noting the position of oil seepages on the crests of anticlines in Gaspe peninsula. Sir William apparently was not much impressed with his own idea at this time, but after the Drake well discovery in 1859 and the publication by Henry D. Rogers, of Glasgow University, formerly of the Pennsylvania Geological Survey, of a paper in which he pointed out that the seepages in Pennsylvania were on anticlines, T. Sterry Hunt, an associate of Sir William Logan on the Geological Survey of Canada, published a reasonably comprehensive statement of the anticlina theory in the Montreal Gazette on March 1st, 1861. Hunt recognized the fact that the oil ?being lighter than the water which everywhere penetrates the rocks below the water level, naturally rises and accumulates along the crown of these anticlines". This was a recognition of the fact that gas, oil, and water in an anticlinal structure separate according to buoyancy or specific gravity. For some years the anticlinal theory does not seem to have attracted much attention, but when I. C. White in 1883 revived it and put it to practical use by prospecting for 'anticlinal' oil an gas structures in Pennsylvania, West Virginia, and Kentucky, its real value not as a theory but as a fact became widely recognized. Even today, the search for anticlines as oil and gas structures is being vigorously continued. In the past fifty years, however, it has become widely recognized that petroleum and natural gas collect in many different types of structures, and these have become known by the general name of 'traps'. About 1890, terrace structures were highly regarded because it was thought certain oil fields in Pennsylvania, New York, and Ohio were directly related to them. However, as Wilson (2, p. 437) has pointed out, it is recognized to day that ?'wherever the surface evidence is complete and dependable, other factors (than the terrace structure) are found to be in control'.

Jan 1, 1948

By J. N. Brooke

"This paper deals with the training of the mining and mineral engineer and the role that these professional people must play in their company environment, particularly in relation to management.THERE IS SOME CONCERN in the mining industry that the numbers of engineering graduates attracted to it and the academic training that these people have received is inappropriate. Evidence for this is:1. -The meetings and studies initiated by the various mining engineering societies to discuss:(a) attracting students and graduates to the industry; and (b) the appropriateness of the present academic training for the needs of the industry."

Jan 1, 1968

AT the Annual General Meeting held in Winnipeg last March, the whole of one of the technical sessions was devoted to a special Symposium on Geological Investigations in Canada, introduced by a paper entitled The Geological Survey (lî which had been specially prepared by Dr. G. A. Young, Chief Geologist of the Survey, and had been published in the February BULLETIN, prior to the meeting. Geologists from each of the provinces contributed to the Symposium, including directing officials of the geological divisions of provincial Departments of Mines, representative geologists from the Universities, and company and consulting geologists. Space, unfortunately, does not permit publication of a complete record of the proceedings,_ or even inclusion of all contributions to the discussion. The following summary, however, gives what is believed to be a fair cross-section of the opinions expressed by representatives from each Province. The Symposium resolved itself largely into a discussion as to how the Geological Survey and the several provincial bureaus or divisions of geology could co-operate most effectively in the important task of carrying out geo-logical investigations, with avoidance of duplication of work and waste of effort, and, so far as broad principles are concerned, there was remarkably close agreement among those participating in the Symposium as to how the various types of investigation should be allocated as between the Federal and Provincial organizations. Briefly, the concensus was that the Geological Survey can render the most effective assistance by conducting reconnaissance investigations, with mapping at 4 miles to one inch, leaving to the provincial organizations the more detailed, and hence more local, studies and mapping at larger scales. There was general agreement that the preparation of base maps, essential to systematic geological investigation, is a service devolving upon the Federal Government.

Jan 1, 1940

By Thomas M. Ware

"MR. Chairman, our Honourable Minister, Mayor Cole, it is a pleasure for me to come here, and join with you in one of the largest industrial shows ever held in Saskatchewan.It is an honour to be asked to keynote your meeting, to help mark an early chapter of this new industry for Saskatchewan. God has placed in our hands a new resource for His man on earth. This store of potash, 350 million years in the making, offers a vital resource to help man support his advanced intellect for thousands of years. It is a gift so large we must all wonder at its purpose and our responsibilities in serving our fellow man with it.We who are here to plan and implement the development of this essential mineral resource enjoy a great -privilege; and we share a great responsibility -to see that the billions of tons of potash which have waited beneath these prairies for millions of years are widely and wisely used to nourish the earth through future millenniums.To know the true value of potash, to be able to bring forth this re-source from over 3,000 feet deep in the earth, to establish markets and develop its potential worldwide is all part of our great heritage from generations past. So I think it is fitting on this occasion that we reflect for a moment on this heritage, to help us assess the responsibilities of its future development."

Jan 1, 1966

By N. L. Richards

In manufacturing for the 21st century, the first company to market often leads the pack in product development and sales. In this respect, manufacturing processes play an important role in transforming “raw materials” into a product(s) for sale to a customer. Thus it can be seen that upfront modelling of a design concept, or modelling of manufacturing processes in a plant, can play an important role in effectively ensuring the overall design and manufacturing route is carried out in an expeditious manner. In the paper various scenarios are considered with respect to modelling the microstructure and/or process, in various manufacturing processes. Also considered are the effects of service condition on the manufactured product in terms of creep and fatigue.

Jan 1, 2010

By Tyson Birketi, Françoi Robert, Steve Green, Dan Richardson

Detailed sampling using a portable diamond drill, and inter laboratory comparison of selected samples have been combined with statistical studies of truncated populations to establish the gold content of several outcrops in the Val d'Or area. The outcrops chosen are non-mineralized. The background gold concentration in the rocks of the region is 5 ppb or less. Gold is distributed relatively homogeneously within the outcrops studied except for slightly increased concentrations within quartz-tourmaline veinlets. Three samples, of which 20 grams of powder are analyzed for each, can adequately determine the gold concentration of a structurally simple outcrop in the Val d'Or area.

Jan 1, 1992

By Paul B. Warrington

This paper presents a discussion of the factors affecting copper scrap markets, including such items as price levels, freight. grades of material, sources and packaging. Reference will also be made to the effective life and turn-around of the copper content of some products. Introduction IN TERMS OF SIZE, copper scrap is second only to ferrous scrap in tonnage recycled. However, in total value, it is second to none. For example, world scrap recovery during the preceding 4 years averaged just under 2,300,000 metric tons per annum, and at an average price of 70 ¢ a pound, this works out at a turnover of about $3.5 billion, which indicates that the copper scrap industry, or recycling as it is now becoming known , is a substantial one.

Jan 1, 1977

By D. H. Flather, J. W. Hendry, K. Drover

Black Hawk Mining Inc. has completed a comprehensive program on the prediction and management of acid rock drainage (ARD) at their Keystone Gold Mine (Keystone) near Lynn Lake, Manitoba. The program, initiated in 1994, followed a phased approach utilizing initial acid-base accounting (ABA) results and subsequent laboratory kinetic testwork to define site-specific sulphide oxidation and neutralization consumption rates in waste rock. Net acid generating waste rock at Keystone was defined through the kinetic testwork as waste rock yielding a net potential ratio (NPR) of less than two. A preliminary waste rock management program based on blending of potentially acid generating and acid neutralizing waste rock was advanced. Subsequent refinement of the management program followed the analysis of over 1580 ABA samples collected from individual blast holes during the initial bench development phase of the Keystone pit. Uncertainties in actually achieving adequate blending within the dumps at a mining- scale resulted in the development of a revised waste rock management program based on segregation. Recognizing that any successful management plan requires that the ARD characteristics of the waste rock be identified prior to in-pit blasting, the extensive ABA database was utilized to develop a rapid characterization scheme. By implementing a characterization scheme based on total sulphur concentrations and fizz rating, waste rock could be quickly segregated without delaying the natural flow of ore from the pit. Interestingly, it also became apparent that gold values were strongly correlated with total sulphur, such that traditional fire assays were supplanted with a simple and more cost-effective total sulphur determination. The program highlights the importance and benefits of collecting and exploiting data beyond that necessary to acquire appropriate development permits.

Jan 1, 2000

By H. F. Naldrett

"AbstractAt the end of May, 1950, Imperial Oil, Limited, had completed a total of 192 D-3 wells in the Leduc-Woodbend field, 62 of which lost circulation in the D-3 zone for periods ranging from two hours to fifty days. The majority of the remaining wells •lost some mud without actual loss of returns. In addition, independent operators completed 69 D-3 wells, of which 9 lost circulation. Included among the latter is the now well known Atlantic No. 3 well, which blew wild out of control for seven months. The well was finally brought under control through two directionally drilled wells, but not before the derrick fell and the well caught fire. Practically all known filler materials have been used in attempt3 to prevent or regain loss of circulation, but none has been successful, except in minor cases. Ordinary sawdust has come to be the most commonly used filler material and is added to the mud before the D-3 zone is contacted. In cases of serious loss of circulation, the on1y successful method of getting returns has been the use of a series of small cement plugs.IntroductionThe Leduc field is twenty miles southwest of Edmonton, Alberta. Geologically, it is on the east limb of the Alberta syncline, in the homoclinal belt. The main productive zones are in the Upper Devonian formation and are known locally as the D-2 zone and D-3 zone, respectively (see Figure 1).The D-3 zone is a dolomitized reef with fair average porosity and permeability, and shows considerable evidence of vertical fracturing. Porosity is mainly due to moderately uniform development of vugs which are interconnected by small crevices. However, the formation is known to be, locally, extremely vuggy and in places cavernous. These latter conditions create very serious drilling problems due to the hazard of loss of circulation, particularly in the gas cap, which has a maximum thickness of 200 feet. The D-3 zone is contacted at an average depth of 5,300 feet."

Jan 1, 1950

By D. J. Wesolowski, D. A. Palmer, P. Bénézeth, S. Hilic

The equilibrium solubilities of gibbsite, Al(OH)3, and boehmite, A1OOH, have been extensively studied in our laboratory from 30 to 90°C, and 100 to 300°C, respectively, to ionic strengths of 5 mol.kg-1 (NaC1) over a wide range of pH. The resulting solubility constants have been treated with consistent empirical models that incorporate appropriate experimental data taken from the literature. These studies were initiated in part to understand and quantify scale formation in geothermal fields as a result of fluid re-injection from electric power generating plants. Most of the experimental results were obtained through application of a unique potentiometric method that allows for rapid, precise measurement of the in situ pH and allows the approach to equilibrium to be monitored from under- and super-saturation. The experimental program was extended to deal with more basic solutions (e.g., five molal NaOH), in which the dissolution of boehmite was measured for application to the refining of bauxite by the Bayer process. More recent results in strong caustic solutions at temperatures below 90°C were obtained to investigate the dissolution of aluminum-containing sludge from holding tanks at the Savannah River waste reprocessing site. In this case the solubility enhancing effects (kinetic and equilibrium) of triethanolamine were also established and quantified. Finally, potentiometric solubility experiments were conducted (50°C in 0.l mol-kg-1, NaCl) on aluminum alloy sheets to identify mainly the nature of the aluminum oxide/hydroxide surface layer formed under these conditions.

Jan 1, 2004

By J. S. Fox

"Besshi-type Cu-Zn (-Ag-A u ± Co) deposits are tabular, stratiform volcanogenic sulphide bodies which are usually associated with mafic volcanic rocks of oceanic or intra-plate geochemistry, but which can also be found locally with ultramafic volcanics or subvolcanic mafic intrusions. A thick sequence of continentally-derived clastic sediment usually encloses both the mafic volcanics and the ore. Besshi-type deposits form subaqueously, in epicratonic rifting environments, more-or-less proximally, and as a result of hydrothermal convection in their subjacent mafic volcanic - clastic sedimentary piles. They belong to a rift -related metallogenic spectrum that includes sediment-hosted and Cyprus-type base metal deposits, and may diller genetically from these mainly with respect to rate and degree of crustal extension. Modern analogues to these deposits are f ound in the submarine volcanogenic sinters of the Gulf of California rift system.The associated lithologies and tectonic selling of Besshi-type deposits clearly distinguish them from Kuroko-type ores. This difference also seems to be reflected in their lead isotopic character. For example, leads from Besshi-type deposits in the Sanbagawa belt of Japan and from the Blue Ridge belt of southeastern U.S.A. lie on extended anomalous lead lines and have lowslopes in 207Pb/204 Pb - 206Pb/ 204 Pbspace (Sato and Sasaki, 1980; Leriuray, 1982), wheras those from most Kurokotype mining districts exhibit only narrow isotopic ranges and lie near or on the orogene growth curve (e.g. , Franklin et a I., 1981). More over, where Besshi- and Kuroko-type deposits are found in the same orogene, the former often occur earlier in the tectonic cycle than the tatter (e.g., Japan, the Norwegian Caledonides, the southern Appalachians and south-central Finland).Besshi-type deposits are not confined to any particular part of the world, or to any geological epoch. Moreover, in many mineralized belts, Besshi-type deposits are the predominant volcanogenic ore type. On a world-wide scale, deposits of this type therefore constitute an important base metal resource."

Jan 1, 1984

By Dave Thomas

?Uranium is a common trace metal at the earth?s surface, but these are amazing super-high grade (up to 25%) pods, veins and disseminated uraninite (UO2) near unconformities between Proterozoic siliciclastic red beds and metamorphic basement with graphitic metapelite and radiogenic granite. ?Pitchblende fills extensional features in reactivated fault zones and replaces matrix in sandstone ?One mining district in Canada ?the Athabasca Basin ->30 deposits /prospects -most in eastern ¼of basin -produces 1/3 of world?s U -employs northerners -VERY high tech -VERY high safety standards Unconformity-associated uranium depositsUnconformity-deposits

May 1, 2006

By Jan Kvinge, Aina Opsal Bakke, Yanjun Li, Jan-Ove Løland, Svein Jørgensen

"Compound casting is a very attractive approach to reduce the weight of components for some specific applications while keep both the functional and the mechanical property requirements. In this work, Al-7Si-Mg alloy /copper compound castings were produced through a low pressure die casting process. To reduce the oxide present in the interface, flux coating of the copper pipes was tested. The interface layer formed between the two alloys was investigated using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Vickers Micro-hardness was also measured across the interface. Results showed that the flux coating prevented the formation of the metallic bond between copper and aluminum. Instead, high concentrations of potassium, magnesium and fluoride, coinciding with formation of KMgF3 and MgF2, were detected in the interface. In the castings without surface treatment, a continuous metallurgical bond was achieved. In the bond layer, various Al-Cu intermetallic phases have been detected. In addition, formation of primary silicon particles in the reaction layer was observed in all castings. The mechanism for the formation of the intermetallic phases and the strength of the interface layer have been discussed.INTRODUCTION Recent development in the automotive industry has focused on producing lightweight components, which can reduce CO2 emission and increase the efficiency. Often, one material alone is not able to meet the requirements for a specific use. The need for lightweight bimetallic components has therefore increased. Aluminum-copper bimetallic components can be used in wires and bus bars where conductivity is an important factor (Lee, Bang, & Jung, 2005). Compared to Al-Cu alloys, Al-Cu bimetallic components can reduce both weight and cost without reducing electrical and thermal conductivity (Sheng, Yang, Xi, Lai, & Ye, 2011). A challenge is, however, that aluminum and copper have high affinity to each other, especially at elevated temperatures. This causes formation of brittle intermetallic phases with high electric resistance (Liu, Wang, Sui, Wang, & Wenjiang, 2016). In addition, both metals are subjected to oxide formation on the surface. Copper is especially exposed to oxidation at elevated temperatures (Pinnel, Tompkins, & Heath, 1979), while a thermodynamically stable oxide layer will spontaneously form on the aluminum surface (Papis, Loeffler, & Uggowitzer, 2009). Oxides are known to be passive substrates, which will reduce wettability and will thus prevent the formation of metallic bonding between aluminum and copper (Papis, Hallstedt, Löffler, & Uggowitzer, 2008)."

Jan 1, 2018

By I. Le May

"The assessment of integrity in plants is discussed, together with the codes that are being developed for in service evaluation of engineering fitness for service. The use of Risk Based Inspection is described and some examples are provided of the evaluation of in service components in which flaws have been detected. An example of the assessment of the structure of a mine processing facility is described, and application of Risk Based Inspection and plant assessment procedures to mines is discussed. Periodic assessment of large plants and components to determine their integrity for continued safe operation is becoming a more accepted approach than formerly when regular shutdowns were the normal practice. This is on the way to becoming the preferred procedure for petrochemical plants and power generating plants, and the same philosophy is appropriate for many mining operations. Both the American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME) have committees developing codes for the continued operation of equipment as distinct from the existing design codes. The philosophy is one of risk-based inspection, which can be on a purely qualitative basis or more quantitatively based.The purpose is to reduce the inspection of unnecessary and non-critical items and to concentrate on the most critical components, reducing costs and downtime and increasing safety. The approach differs from that considered by many maintenance engineers, in that defects that are identified during an integrity evaluation do not automatically cause a component or structure to be condemned or require that repairs are made right away. The seriousness of the defect must be considered and the safe operating life can be estimated before it becomes necessary to replace or repair the unit or component. This is no different from what is done today with passenger aircraft and, to an increasing extent, with pressure vessels, reactor vessels and similar components in the petrochemical and power generating industries."

Jan 1, 1998

By Leslie S. Weldon

THE Lake Shore mine has been developed by two vertical shafts, with level intervals at 200 feet to the 2200 level and at 125 feet below this horizon. A main cross-cut joins the two shafts on all levels to the bottom of No. 3 shaft, and opening into these cross-cuts are the ore passes and sand passes, which are completed from surface To the 4450 level. In the west part of the mine, additional connections have been made between No. 1 and No. 2 veins, through which the major part of the ore from No. 2 vein west is routed to drifts in No. 1 vein. With the lesser amount of stoping on No. 1 vein, this arrangement permits better haulage to be maintained. The ore passes are driven at 50 degrees from the ends of short cross-cuts off the main ones and are broken through to the levels above at the mouths of the short cross-cuts, to allow for dumping on each level. The passes are controlled at each level by ball-and-chain gates and deliver to crushers and thence to loading pockets, shown in Figure 1. That system is quite flexible in that it is possible to by-pass the crushers at any station and load from either shaft at a number of different pockets. The sand passes are driven from the main cross-cuts at the same inclination as, and parallel to, the ore passes. Each is equipped with a chute and dump hole, so that waste or sand fill may be loaded or dumped at each level. A transfer door, hinged on the bottom, is installed opposite the chute for by-passing fill from one level to the next, and in the closed position protects the opening at the top of the pass. The dump hole situated beside the transfer door is protected by a grizzly with 10-inch spaces. Waste rock may be withdrawn from the system through No. 3 shaft loading pocket at the 2950 level to a waste bin on surface. Levels are developed by drifts in No. 1 and No. 2 veins for their entire lengths. Subsidiary breaks are followed at a later date, when full information has been obtained by exploration, and a considerable amount of development by sub-drifts is carried out in the upper part of the mine, particularly in more or less erratic sections of No. 1 vein.

Jan 1, 1936

By D J. McDougall

Due to changes in the solid-state conditions of minerals in the rocks surrounding hydrothermal, contact meta-somatic or metamorphosed ore deposits, positive or negative thermoluminescent anomalies may be found in their vicinity. Several types of equipment which can be used for both quantitative and semi-quantitative measurements of the emission are discussed and compared. Methods of selecting, preparing and testing samples to ensure reproducible results are outlined, along with the kind of data which can be obtained from different types of equipment. The normal thermoluminescence of rock-forming min~ erals in the common rock types is noted, and variations in the solid-state conditions in the wall rocks which will cause marked increases or decreases of true thermoluminescence are outlined, as well as the thermolum-nescence-like emissions which are present in the vicinity of ore deposits. Introduction T HERMOLUMINESCENCE occurs when certain crystalline materials are heated to temperatures ranging between 180' and 400°C. The light emission can be ascribed to the release of electrons metastably trapped within the crystal lattice, with peak emissions taking place at temperatures which are more or less specific for a particular set of traps; the area under

Jan 1, 1965