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By James Stenhouse

Abstract The aqueous oxidation of pyrite in caustic solutions under oxygen pressure was investigated by measuring that effect of reaction variable on oxygen consumption by the reactions. From the results of this investigation, a model for the process has been proposed. In this model, sulphur diffuses as a positive ion through an oxide layer which forms on the sulphide particles and is then oxidized to sulphate ion. Iron is oxidized by substitutional diffusion of oxygen atoms into the oxide layer. The effect of most reaction variables on the rate of oxygen consumption can be explained with this model. Introduction Recent investigations (1,2,3) have shown that certain sulphide ores can be readily leached by agitating the ore in the form of a pulp under pressure in the presence of oxygen. Since very little was known of the mechanism of this oxidation, a programme of investigation was inaugurated in 1949 in the laboratories of the Department of Mining and Metallurgy of the University of British Columbia. Financial support for the investigation was received from the National Research Council in the form of student grants and bursaries, from the Canadian Liquid Air Company, Limited, and from the Consolidated Mining and Smelting Company of Canada, Limited. The first objective was to devise a technique to study the primary oxidation reactions in aqueous solutions and to apply the technique to a detailed study of the oxidation of pyrite in caustic solutions.

Jan 1, 1952

By J. F. Wang, Y. Jin, Z. L. Wang

Smelting reduction as an ironmaking technology for the 21st century has been challenging the traditional blast furnace. The process has many attractive advantages over the blast furnace, however, the massive by-produced coal gas mainly containing CO, H2 and CO2 requires further treatment. From a chemical engineering view, coal gas is a valuable chemical stock and can be transformed into hydrogen-rich synthesis gas. Hydrogen can be directly used as clean fuel and synthesis gas can be used for the production of some important chemicals such as methanol, ammonia and dimethyl ether. Among those chemicals, dimethyl ether as an alternative clean fuel for diesel engine and liquefied petroleum gas has been drawing more attention. It has excellent environmentally-benign behaviours not only in compression ignition combustion, but also in the much lower emission of SOx and NOx. In this work, a combined technology of smelt reduction ironmaking and direct synthesis of dimethyl ether, which will strongly promote the energy efficiency, environmental protection and resource recovery, is proposed and described in detail.

Jan 1, 2004

By G. W. Davies

"IntroductionThe development of British Columbia's northeast coal deposits, represents the single biggest industrial undertaking in British Columbia's history.As a result of this development, several thousand jobs were created, hundreds of millions of dollars in new tax revenue and billions of dollars in new foreign exchange began flowing into Canada.The Northeast Coal Development began in 1981 with the signing of sales contracts to ship a total of 6.5 million tonnes of metallurgical and additional quantities of thermal coal annually to Japan over a 15-year period. The current long-term agreements contain provisions for extension to 20 years.The sales contracts with a group of Japanese steel mills were signed by two Vancouver-based mining companies, Quintette Coal Limited and Teck Corporation. The agreements followed years of exploration and negotiation beginning in 1968.The first shipment of coal from Quintette and Teck's Bullrnoose Mine was transported by BC Rail and Canadian National Railways to the Ridley Island coal port in the fall of 1983."

Jan 1, 1992

By James E. Rider

"Fractures in mine hoist drumshafts are rare. We know of no previously reported attempts to repair a fractured drumshaft; any feasible method would involve welding and the associated problems of distortion, crack formation and strength.In June 1984, a fracture was discovered in the drumshaft of the production hoist in the Teck Corporation, Lamaque Division Mine at Val d'Or, Quebec. Delivery time on a new shaft would have been at least six months. The shaft was repaired in ten days and the total out -of-service time was four weeks.This paper describes why the shaft failed, how it was repaired, and the special alignment procedures employed during re-installation to minimize stresses in the repaired area.IntroductionThe performance of a mine hoist drumshaft is absolutely critical to mine operation. An inoperable drumshaft means no hoist, which in turn means no production or mine operation.Fractures in mine hoist drumshafts are rare. Previously when they have occurred, no one has seriously considered attempting a repair because of problems involved. Any feasible method would involve welding, which raises several major problems - namely, metallurgical, alignment, and strength.In July 1984 this very situation occurred at the Teck Corporation, Lamaque Division Mine in Val d'Or, Quebec.It was recognized that a new shaft would take at least 6 months' fabrication and delivery time. However, having had some experience at repairing broken shafts in other machines under similarly desperate circumstances, and after due consideration, it was concluded that by applying the correct techniques and engaging the right expertise, it would be possible to perform a repair and have the mine back in operation within a month.Thanks to outstanding efforts by all, the repair was accomplished in ten days and total out-of-service-time was only four weeks. The causes of the failure were determined and the calculated stress levels confirmed by strain gauge measurement during operation.The success of this project was achieved by adhering rigorously to fundamental management and engineering principles."

Jan 1, 1988

By James E. Rider

"Fractures in mine hoist drumshafts are rare. We know of no previously reported attempts to repair a fractured drumshaft; any feasible method would involve welding and the associated problems of distortion, crack formation and strength.In June 1984, a fracture was discovered in the drumshaft of the production hoist in the Teck Corporation, Lamaque Division Mine at Val d'Or, Quebec. Delivery time on a new shaft would have been at least six months. The shaft was repaired in ten days and the total out -of-service time was four weeks.This paper describes why the shaft failed, how it was repaired, and the special alignment procedures employed during re-installation to minimize stresses in the repaired area.IntroductionThe performance of a mine hoist drumshaft is absolutely critical to mine operation. An inoperable drumshaft means no hoist, which in turn means no production or mine operation.Fractures in mine hoist drumshafts are rare. Previously when they have occurred, no one has seriously considered attempting a repair because of problems involved. Any feasible method would involve welding, which raises several major problems - namely, metallurgical, alignment, and strength.In July 1984 this very situation occurred at the Teck Corporation, Lamaque Division Mine in Val d'Or, Quebec.It was recognized that a new shaft would take at least 6 months' fabrication and delivery time. However, having had some experience at repairing broken shafts in other machines under similarly desperate circumstances, and after due consideration, it was concluded that by applying the correct techniques and engaging the right expertise, it would be possible to perform a repair and have the mine back in operation within a month.Thanks to outstanding efforts by all, the repair was accomplished in ten days and total out-of-service-time was only four weeks. The causes of the failure were determined and the calculated stress levels confirmed by strain gauge measurement during operation.The success of this project was achieved by adhering rigorously to fundamental management and engineering principles."

Jan 1, 1988

By P. Hale

"The trend to drives of more than 10,000 hp on large-capacity ball and autogenous mills for increased operating efficiency has been limited by factors in the conventional drive system. A solution to this problem, using modern developments in static converter technology, is the concept of driving the mill directly without gearing using a low-speed, low-frequency synchronous motor with a cyclo-converter power supply.This paper presents various practical arrangements of mill and low-speed motors giving the specific advantages of each system. The means of controlling inrush currents on starting and of spotting by the use of variable-frequency control are outlined in general form. Several gearless ball mill drives are scheduled for start-up in European cement plants and further orders have been placed."

Jan 1, 1970

By A. C. Moerman, C. W. Pelley, K. R. Notley

"The software package described in this paper facilitates the handling of diamond drilling information in the creation and maintenance of a geological information database. Once entered, the drilling information is stored in a direct access file for rapid retrieval. The drill data are sorted into vertical cross sections and interpretation is performed using on-screen menus to define areas of common rock type and outline the mineralized zones. Intersections of individual zones can then be examined and outlined in the longitudinal dimension at a graphics terminal.With the aid of surface-fitting routines, the digitized information can be used to generate three-dimensional models of each zone. From these models intermediate cross sections and level plans can be obtained. Several interpretations are possible and plotter drawings can be obtained. An output file for use by ore reserve estimation software can also be created.Future work will tie this software to geostatistics and mine planning programs and will be aimed at converting mainframe software to run on microcomputers. IntroductionComputer applications in underground mine planning and geology are not new. Operations such as Sherritt Gordono and Kidd Creek have been using software developed about a decade ago for handling geological information and designing stoping blocks. However, general use of such systems has been limited mainly due to the cost of hardware which was affordable only to large corporations. Software to perform the work was usually developed on site and was largely unavailable for use by others, being site-specific, or too expensive for other organizations to purchase.The increasing power of microcomputers and mini-computers, and their relatively low cost compared to the mainframe computers which were previously used, has led to the increased use of computers at mining operations of all sizes. Sources of software for use in geological interpretation and mine planning have increased in number with the proliferation of the use of microcomputers."

Jan 1, 1988

By M. Potesser

In the past, different furnace types have been developed for use within the copper industry, with two common anode furnace designs typically used in copper smelting plants worldwide: the tiltable reverberatory furnace (KPO) generally used for the secondary copper industry and the cylindrical or drum type anode furnace (TRO) for handling a liquid blister charge generated in primary copper production. The disadvantage of the KPO is its design related to the longer refining period, because of the low bath depth, however it provides good conditions in the melting period due to its large bath surface. On the other hand, small amounts of scrap charged into the TRO increase the melting and dissolution period, but it provides good conditions for the refining period. The newly-developed elliptical furnace concept (TRE) offers the advantages of each of these furnace types. The special design allows melting of the scrap more efficiently than in the KPO and refining the liquid copper more efficiently than the TRO. This paper shows a metallurgical comparison of the three furnace types in regard to the melting period by heat technological considerations (optimized arch design) and of the refining period done by CFD with concentration on current, recirculation and dwell time of the gas in the melt. The paper outlines the possibilities for a reduction of the tap-to-tap time and energy consumption as well as for an increase of the production capacity, which can be achieved by applying the TRE instead of the conventional furnace designs.

Jan 1, 2007

By H. G. Ames

"The property of Perron Gold Mines, Limited, lies in the southwest corner of Pascalis township, northwestern Quebec. It is approximately 12 miles northeast of the town of Val d'Or.This ground was originally staked by Jack Mathews of Amos in the spring of 1931. Shortly after staking, a quartz vein containing visible gold was uncovered on the south boundary of the property, about 400 feet south of the present shaft. With further prospecting, another spectacular goldbearing vein was found 3,000 feet northwest of the original showing. Subsequently, several programmes of exploration were carried out in search of the main ore zone. By 1933 sufficient ore was outlined to warrant sinking a shaft. The first ore was milled in 1934.Total production from the Perron mine from commencement in 1935 to 1944 has been 317,900 oz. gold having a value of $11,935,106. The average recovery a ton for 1944 was $9.01."

Jan 1, 1954

By M. R. Henzinger, G. Lenz, A. Gaich, Pötsch, W. Schubert, P. Wagner

"The better the information on the rock mass and its fracture system, the better is the basis for any rock mechanical decision that is required during the excavation process. While in conventional tunnelling free view to the tunnel face is available, possibilities are limited for mechanised tunnelling using a tunnel boring machine (TBM). An approach, already formulated in 2005, is used that produces digital photographs through openings in the cutting wheel of a TBM and merges them into a circular three-dimensional image. The 3D image is then used for geometric rock mass characterisation purposes including geological mapping, for example to measure spatial orientations or determine joint spacing. In the paper the basic concept is described together with first results from a pilot test.INTRODUCTIONA three-dimensional image unites digital photographs with spatial information on the objects/surfaces it shows. Since they combine geometric and visual information they are a straightforward source for geometric rock mass analysis and geological mapping. Their obvious benefits among others are: (i) they allow spatial measurements even in inaccessible regions, (ii) they provide objective and reproducible records of the rock mass conditions, and (iii) they increase working safety (Gaich et al. 2004).Pre-requisite for the generation of 3D images is the acquisition of at least two photographs from the region of interest. From the photographs the imaged object surfaces are reconstructed by means of image analysis using methods from photogrammetry (Slama, 1980) and computer vision (Hartley & Zisserman, 2001). See also Figure 1."

Jan 1, 2015

By John Porritt, Alain Dorval

"TioMin Resources Inc. is evaluating the feasibility of exploiting the heavy mineral sands deposit at Natashquan on the north shore of the Gulf of St-Lawrence, Quebec. TioMin holds the exploration rights to 180 square kilometres, on which 1.6 billion tonnes of sands grading approximately 6% heavy minerals were outlined. The heavy minerals of value include magnetite, ilmenite/hematite, garnet, and zircon. An important part of this evaluation is the development and testing of a mineral separation flowsheet. Under a comprehensive mandate from TioMin, the Centre de recherches minerales (CRM) provided technical assistance to build and operate an on site primary concentrator pilot plant. This plant produced a 93 tonne concentrate, providing over 60 % heavy minerals. This concentrate was shipped to the CRM pilot plant in Quebec City. It was used for further flowsheet testing and for preparation of products and concentrates of heavy minerals with regard to marketing possibilities. This paper presents the flowsheet developed to produce these concentrates.IntroductionIn late 1992, an 11 tonne bulk sample of sand was collected from within the mineralized zone of the Natashquan deposit. This sample was processed over conventional spirals and wet tables at the pilot plant facilities of the Centre de recherches minerales (CRM) in Quebec City. A primary concentrate was produced, from which several 20 kg samples were forwarded to five research laboratories in North America and in Australia. Their tasks were to determine the mineralogical composition of this concentrate and the potential for recovery of marketable minerals from the heavy mineral sands. Satisfactory results obtained from this approach encouraged TioMin to proceed with a more detailed pilot plant program."

Jan 1, 1995

By R. A. Rabnett, G. Paget, Patrick Walsh

"Tumbler Ridge, Canada's newest resource community, has been developed differently than have been other resource communities.Since its conceptualization, emphasis has been placed on the establishment of a traditional municipal government at early a stage as possible.Planning f or the community goes back to 1977. By then, extensive study by provincial agencies had shown a new resource town would be required to exploit north east coal. The Ministry of Municipal Affairs, in conjunction with a consultant named R.A. Rabnett began the extensive Tumbler Ridge conceptual plan.The results of the conceptual plan are evident in the organizational and planning goals of Tumbler Ridge. In every aspect from the election of officials to some financial matters, the town functions as a normal municipality. With the resource companies of the North East Coal Development within its municipal boundaries. Tumbler Ridge has been able to debenture its capital projects against its municipal tax base.The town's ability to function as a normal municipality is enhanced by its control over Crown land it has purchased from the province. This gives it further control over the development of the community and helps in establishing agreements with the resource companies and the provincial government to ensure that housing and service needs are met. While resource company representatives sit on certain municipal committees, their roles are advisory in nature.The community continues to move toward full municipal status and will have a fully elected Council by 1986.BackgroundPlanning for the development of northeast British Columbia coal resources began in 1976 under the aegis of the provincial Cabinet Committee on Coal Development. A series of subcommittees were established including a Townsite/Community Development subcommittee. The Ministry of Municipal Affairs chaired this subcommittee and continued as the lead agency for the provincial settlement planning effort over the period 1976 to 1981."

Jan 1, 1983

By G. Begin

"The expansion undertaken at Selbaie in 1985 necessitated an adaptation and expansion of the equipment maintenance system. This paper relates briefly the stages of transformation of the maintenance administrative structures, work methods and tools. The maintenance in a mechanized mine requires an expenditure level in the order of 20% of the total operating cost of the enterprise. Thus, the maintenance organization was modified to apply more computerized planning and follow-up, and the role of preventative maintenance was further advanced.IntroductionAs far as maintenance is concerned at Selbaie, the scenario described herein is a resume of the current situation. Although positive results have been obtained, this outline is in no way a detailed account of a fail-proof maintenance system.Once zone A-I was put into production, the expansion the mine experienced in 1985 had a direct impact on the equipment maintenance system. As centralized as it was in the beginning, the system is now partially decentralized.The over-all changes to the maintenance department demonstrate the flexibility required by organizations in new situations. In spite of the exceptional results obtained before the expansion, it became evident that both the maintenance and production sectors would have to be combined. In doing so, a more appropriate coordination of maintenance work could be obtained and the maintenance staff would obtain a more detailed knowledge of the equipment in each sector. In addition, by keeping the general and specialized departments centralized, it was possible to offset the negative effect s of a decentralized system, namely too much manpower."

Jan 1, 1990

By Robert B. Wickham

"American Barrick has always balanced its aggressive operating approach with a conservative financial strategy. In fact, what enables their mining team to pursue such aggressive plans with confidence is the conservative financial strategy adhered to by the company. These policies are built on a prudent mix of gold linked financings, equity and gold price hedging.This paper outlines these policies and focusses in particular on American Barrick's gold price hedging program.IntroductionThe company's balance sheet at the end of 1990 clearly shows the wisdom of its conservative policies. Total assets have grown to over US$1 billion; cash has grown to US$312 million and shareholders' equity to US$645 million. All amounts included in this paper are quoted in U.S. dollars. Increased gold production and an effective gold price hedging program also combined to produce record income from operations, earnings and cash flow in 1990.The first half of 1991 is also indicative of the benefits of the company's conservative financial policies. Increasing production, together with its comprehensive gold hedging program, has generated increased earnings, even in a period of falling gold prices.All year-over-year numbers for the first six months are up. Gold production was 36% higher; earnings of $40.2 million $ 0.30 per share - were 46% higher than 1990.Barricks revenue continued to increase despite gold prices remaining unchanged during 1990. Barrick's hedging policy protects the company from falling gold prices on the basis that the upside looks after itself. Their hedging program - including various goldlinked fmancings - enabled Barrick to realize an average price of $437 per ounce of gold sold in 1990, compared with the Comex average gold price for the year of $384 per ounce."

Jan 1, 1991

By M. P. Brameld, R. H. McCorkell

"Overburden covering bedrock uranium deposits was sampled to depths of 29 m and Rn concentrations measured at the same depths. Total-alpha activities, V concentrations and Rn emanation (J) of the samples were measured. The U-flux into the overburden was greater in the past: oxidation and dissolution has since removed most U, leaving decay products which indicate the presence of U deposits when U itself does not. Distributions of U and decay products and their ratios to each other reflect U-migration and degrees of U-removal. Rn distribution in overburden is related to the J of overburden samples and the presence and movement of groundwater. Simple, rapid methods of total-alpha and J measurement are described.IntroductionThe overburden drilling apparatus developed by Bondar-Clegg and Company makes possible sampling and radon measurement in overburden from the surface down to about 50 metres. This apparatus was used here to study the diffusion of uranium and its decay products from ore deposits into over lying overburden at the N deposit of the Amok Ltd. property (Cluff Lake, Saskatchewan) and on the Imperial Minerals Ltd. property at Gooderham, Ontario. These ores are enclosed in bedrock; the overburdens were deposited by glaciers or streams. The migration of uranium and its decay products in such situations and the factors which affect it have been little studied in the past, as readily usable techniques for mapping it in three dimensions have not been available. The results reported here are somewhat sketchy and preliminary, but they indicate the value of the methods used and some of the patterns to be expected. Surface and subsurface sampling and measurements were carried out on 3-line grids crossing known zones of mineralization. The lines were 60 metres apart at Gooderham and 40 metres apart at Cluff Lake."

Jan 1, 1982

By R. Augsten, K. K. Feng, K. C. Cheng

"Methane emission and the desorption characteristics of vertical borehole coal samples of Greenhills multiple seams in the vicinity of Elkford, British Columbia were investigated. Three vertical boreholes at depths of 335 m, 380 m and 395 m were drilled along the west wall of an active open pit mine and 44 core samples from various coal seams were obtained for desorption studies.The results are presented in three tables and illustrated with six figures. The methane content was found to increase significantly at depths greater than 200 m. The adsorption equation by Kim and the properties of the coal have been used to predict the methane content and these were compared with the measured values by the direct method.IntroductionThe coalification of plant material in the sedimentary rock produces different ranks of co al and gases of various composition. The gas mixtures are retained in coal beds and rock strata under pressure. The gas content in a coal bed varies considerably depending on the rank of coal and the depth of overburden. The gas content is defined as the volume of gases adsorbed in a unit weight of coal materials. The net amount of gases remaining in a coal seam depends on the difference in the rate of generation of methane by geo-thermal heat and the rate of diffusion of the gases out of the coal bed through sedimentary cover. The major factor that causes the change in rank and the liberation of gases is the temperature, which is governed by the thermal conductivity of sedimentary cover and the heat flux through the underlying rocks. The rate of diffusion of the gases out of the coal is governed by the porosity of the overlying rocks and the degree of fracture. The measured values of gas content in major North American coal beds are from zero up to 24 cm3 per gram of coal(1,2). A gas content of 2.5 to 9 cm3/g is considered ""gassy"" and that of 9 cm3/g or higher is considered ""very gassy"" for underground mining(3). Normally, the gas mixtures released from bituminous coal in Canada contain 90 to 98% methane and the remainder is made up of CO2, N2, 02, H2, He and other hydrocarbons(4)."

Jan 1, 1984

By G. Morin, S. Amira, F. Chiesa, B. Duchesne

"The effect of heat treatment on the stress corrosion cracking (SCC) resistance of A206 aluminum alloy was studied using the breaking load test according to ASTM G139 standard. This method uses the residual strength measurement from tensile test specimens previously stressed axially while exposed to the 3.5% NaCl alternate immersion test according to ASTM G44 standard. The residual strength after exposure is used as a measure of SCC degradation. The performed heat treatments were conventional natural aging T4 and artificial over-aging T7 tempers in addition to artificial aging T6 temper added for purpose of comparison. These tests showed that A206-T4 has a good resistance to SCC at pre-loads up to 100 MPa while A206-T7 was prone to SCC for pre-loads of 0 and 50 MPa, and showed total loss of ductility for pre-load of 100 MPa. Both A206-T4 and A206-T7 pre-loaded at 150 MPa showed poor resistance to SCC. A206-T6 showed the worst susceptibility to SCC as it lost all mechanical resistance at the end of the alternate exposure to 3.5% NaCl solution, even without any applied pre-load. Metallographic analyses showed that the resistance of A206 alloy to SCC is mainly affected by the transition from pitting to intergranular corrosion attack. The initiation and the propagation of intergranular corrosion attack might be assisted by high stress concentrations in the pits, particularly for pre-loads higher than 100 MPa. The transition from pitting to intergranular corrosion can also be promoted by hydrogen evolution from growing pits, which supports crack propagation by hydrogen embrittlement.INTRODUCTIONA206 aluminum-copper casting alloy offers ones of the best mechanical properties among the aluminum foundry alloys. This alloy belongs to the 206 alloy family developed in 1970s as an alternative to the highly resistant and ductile but more expensive Ag containing 201 alloy (Tiryakioglu, 2009). A206 showed also good low cycle fatigue strength (Sigworth, 2002). These properties made A206 alloy a strong candidate for some vehicles lightweighting applications. In spite of its interesting properties cited above, A206 alloy was rarely used in critical applications due to its tendency for hot tearing and stress corrosion cracking (SCC). Studies of A206 hot tearing behavior showed that this tendency can be reduced by improving castability and by grain refinement (Sigworth, 2002). The optimisation of the casting design can also prevent the tendency toward hot tearing. The SCC of aluminum-copper alloys arises from their susceptibility to localised corrosion, especially in chloride containing media. The localised corrosion in Al-Cu alloys is caused mainly by their heterogeneous microstructure, where the presence of many phases leads to the formation of micro-galvanic coupling with the matrix. However, most of the studies aimed at investigate the SCC of Al-Cu alloys concerned the wrought ones, especially the AA2024 alloy tempered in the T3 (or derivative) condition and few studies concerned the 206 and cast alloys in general (Alexopoulos, 2009 and 2016; Campestrini, 2000; Vogt, 1998; Talamantes-Silva, 2008; Zhang, 2003). Jean et al. (Jean, 2009) studied the effect of heat treatment on SCC behavior of B206 alloy using alternate immersion technique and grain boundary attack method and did not find direct correlation between the two methods. Another study showed that aging of 206 alloy may make a casting susceptible to SCC (Sigworth, 2002). However, these studies did not provide detailed information about the mechanisms of SCC of 206 alloy, as well as the effect of the stress intensity. The present work investigates the effect heat treatments and the stress intensity on the morphology of the corrosion attack and the SCC behavior A206 aluminum alloy. This study uses the breaking load test according to ASTM G139. This test utilizes direct tensile specimens and was developed to give a more quantitative measure of the SCC performance of resistant aluminum"

Jan 1, 2016

By J. W. M. Porritt, M. P. Brameld, R. H. McCorkell

"Soil-gas Rn was measured by two types of alpha-particle-track detectors, by emanometry and by counting alpha-activity on Rn-decay-product collectors. Soil samples were analyzed for V by fluorimetric and fission-track methods, their Rn-emanation by decay-product collectors and their total alpha activities with track detectors. The same uranium anomalies were revealed by each method. Fission-track analysis of leaves for V showed only random variations with sampling site, and the Rn emanation of trees and leaves removed from them was barely detectable . The agreement among the other methods is significant, total alpha and collector methods are simple, rapid and useful, and a combination of methods at a site would reveal disequilibrium in the U-decay series if present. Track-Rn measurements are highly reproducible and insensitive to apparatus design and their sensitivity is not enhanced by covering the detectors with thin foil or placing them in large containers.IntroductionIn the past two years , a number of methods of geochemical exploration for uranium have been tested by the authors over the known copper-uranium occurrence at South March, Ontario. This was done partly to compare methods and partly to develop and test new ones. The South march deposit has been described a number of times by others(1,2,3,4). The methods included in this study were the following.Emanometry, Radon in soil gas is measured by pumping the gas into the cell of a scintillation counter or emanometer(5,6). Alpha particles from radon (222Rn) and its decay products (218Po and 214Po) produce scintillations of light in the silver-activated zinc sunphide (ZnS(Ag) covering the walls of the cell. These are counted by a photomultiplier tube and scaler, the count ra sulphide (ZnS(Ag) covering the walls of the cell. These are counted by a photomultiplier tube and scaler, the count rate being proportional to the concentration of radon in the soil gas."

Jan 1, 1981

By A. J. Keen

"Cominco's Polaris Mine is an underground lead/zinc operation located on Little Cornwallis Island in the Canadian High Arctic. Polaris is the world's most northerly base metal mine, situated at about latitude 75°N and longitude 97°W (Fig. 1). The closest community is Resolute Bay about 100 km to the southeast.During the construction and development phase Cominco adopted a unique scheme to save time and money. Many facilities including concentrator, powerhouse, shops and warehouse were built on a barge in southern Canada. The barge was towed 4800 km to the site in August 1981. Production at Polaris began in November 1981. The current mining rate is 1 million tonnes per year. The mine employs 250 people with about 190 on site at any time.GeologyThe deposit is a Mississippi Valley type orebody and lies near the top of the Ordovician Thumb Mountain Formation. Ore minerals consist of sphalerite and galena with the gangue being predominantly dolomite with calcite and marcasite. The orebody is situated completely within permafrost, consequently the voids frequently found in the ore are filled with ice. The orebody strikes north-south, dips approximately twenty degrees to the east and takes up an area about 400 m wide by 700 m long. The upper portion of the orebody (60 m to 150 m below surface) lies in an area called the Panhandle Zone. The deeper portion of the orebody known as the Keel Zone extends to 300 m below surface (Fig. 2). The deposit is strongly zoned with a high grade zinc/lead and iron-rich tabular core overlain and underlain by vein, stringer and breccia mineralization. The ore reserves at January 1991 were 14.6 million tonnes at 3.6% Pb, 13.7% Zn, 3.2% Fe, after producing 8 million tonnes at 3.9% Pb and 14.2% Zn since November 1981"

Jan 1, 1992

By R. Thierbach, W. Kahnt, Oberthür. T., D. Eisenburger, V. Gundelach

ABSTRACT: The ground penetrating radar (GPR) method was used in a platinum mine in Zimbabwe by members of the Federal Institute for Geosciences and Mineral Resources (BGR). The measurements were carried out in boreholes and drifts. Electromagnetic re?ections from a fault that consistently trends parallel to the mineralization zone permitted the mapping of the economically minable parts of the deposit. An introduction is given to the geology of the studied area and the application of the GPR method. The electrical parametres of the rocks are measured in situ, the GPR measurements are displayed with radargrams, and the visible structures are explained in illustrations.

Jan 1, 2010