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By R. E. Eyre, L. P. Landucci

C URRENT practice in the zinc concentrate roasting plant of The Consolidated Mining arid Smelting Company of Canada Limited, at Trail, B.C., involves passing the furnace effluent gases through an electrostatic precipitator for the recovery of dust. After removal of the dust the gas is treated for recovery of sulphur dioxide by conversion into sulphuric acid ( 1). However. as roasting techniques improved, and furnace productivity in-creased, the rated capacity of the precipitator was exceeded and it was necessary to consider various means of improving the dust recovery. A study of methods indicated that a baghouse using silicone-treated glass fabric, might be suitable for this particular application. Glass fabric was chosen because the temperature of the roaster effluent gases would range from 450°F to 500°F and tempering air was undesirable to avoid dilution of the sulphur dioxide gas.

Jan 1, 1962

By R. D. Brown

"Finance Minister Donald Macdonald's budget of May 25, 1976 featured a restructuring of the anti-inflation profit controls and a grab bag of tax changes, some of direct interest to the mining industry. All Canadian taxpayers now will be permitted to write off immediately 100% of mineral and oil and gas exploration expenses included after• May 25, 1976 and before July 1 1979. The cost of acquitting Canadian resource property after May 6, 197.4 from a federal or provincial government will now clearly be included in Canadian development expense, and provincial drilling and exploration incentives received after May 25, 1976 will not reduce exploration and development expense for federal income tax purposes. Under tough new anti-inflation profit controls, all controlled businesses, except distributions, will essentially have one uniform set of rules for• determining allowable profit margins; this allowable margin will be determined by product line or by over-all net margin and will be 85% of the higher of the margin obtained in the five years preceding October• 13, 1975 or the one year preceding May 1, 1976. The basic capital cost allowance system is to continue, but many rates will be revised. The ability to offset losses created through claiming capital cost allowances on leased equipment, etc. against other income will be ended with respect to transactions entered into a/te1• budget night. Miscellaneous other tax changes will raise the low rate base for Canadian-controlled private corporations to $750,000 increase retitement plan contribution limits and reduce the rate of branch tax imposed on branches of corporations resident in a country with which Canada has a comprehensive tax treaty to equal the withholding tax rate on dividends under that treaty."

Jan 1, 1976

By W. A. Lang

"I.-IntroductionAn attempt bas been made in this paper to provide a basis for appraisal of the future of the coal briquetting industry in Alberta by outlining the processes used for briquetting various ranks of coal, by specifying the requirements of a briquetted fuel, by indicating .the status of the industry in the United States, by giving developments in Western Canada, by assessing costs of processing, and by discussing briquetting researches in progress. Much of .the detail bas been omitted since this might mask, rather than reveal, the more important phases of the problem. Reference will be made when possible to published articles where many of the details can be obtained.It should be stated at the outset that, in the writer’s opinion, there are three possible developments in Alberta as regards briquetting: (a) an expansion of the briquetting of the fines of • non-coking and coking coals of semi-anthracite, and of low and medium volatile bituminous rank; (b) the processing of the fines of high-volatile C bituminous coals; and (c) the upgrading of the lower rank high-moisture sub-bituminous coals. Details of the chemical and physical properties of these coals can be obtained in publications of the Research Council of Alberta (1, 2), and of the Fuel Research Station, Bureau of Mines, Ottawa (3).Semi-anthracite and low and medium volatile bituminons coals occur in the mountain areas of Alberta, where, during the upthrust of the Rocky mountains, the coal beds served as the sliding surface. This resulted in the coals being; crushed and consequently they contain a h1gh percentage of fines. In some cases they are high in mineral matter and require to be cleaned before being processed. However, the cleaning of fine coal is both difficult and costly. Both the amount of fines present in the mine-run coal and the amount of mineral matter associated with the coal have increased through the introduction of mechanized mining and through the recovery of coal by stripping operations."

Jan 1, 1950

By H. E. Grier, H. H. Aronson, H. F. Coffer

"Nuclear explosions are currently being planned for use in oil and gas production, the recovery of oil from oil shale, gas storage and copper leaching. The current status of each of these projects is discussed, with emphasis on the economics of each application. The first commercial application of nuclear explosives will be in gas stimulation. Project Gasbuggy will be rapidly followed by two additional shots, also related to gas production. These three events, each in a different formation, will be described in this paper with a discussion on their significance to the world's oil and gas industry. The use of nuclear explosives in oil and gas stimulation should be a standard accepted practice within a few years. Calculations based on explosions in media such as tuff, alluvium, granite and dolomite predict large increases in productivity when nuclear devices are used in tight, thick formations. The broken-up rock resulting from the explosion becomes the new well bore, with a production rate of six to twelve times that of a normally completed well.Also included in the paper is a discussion of the real or possible problems associated with nuclear explosive engineering. The only major foreseeable problem is the seismic shock wave. This limits the size of explosive which can be used near important surface structures. A discussion is included on the radiation problem, which we believe to be largely psychological in the case of contained explosions."

Jan 1, 1968

By K. L. Azinger

Successful relationships between mining companies and local stakeholders are now an essential part of the social contract of “doing business” (Prescott, 1995). The methodology presented in this paper is designed to assist mining companies in understanding and building relationships with diverse stakeholder groups. The methodology starts by recognizing that mining projects have a natural life cycle which can be used to identify when new external affairs strategies are required. In designing an external affairs strategy, the first step is to set objectives that are compatible with the overall objectives of the mining project. The management team then identifies the main stakeholder groups and seeks to understand the priorities and inter-relationships of the individual stakeholders. The result of this stakeholder analysis is an understanding of the Degrees of Influence of each of the stakeholder groups along with a relationship map which illustrates the strong interactions between stakeholders. The company is then prepared to take a proactive approach to building relationships with the primary stakeholders. This methodology was developed by BHP to assist with the federal government environmental approval process for the development of Canada’s first diamond mine. BHP has successfully used the methodology in three different phases of the NWT Diamonds Project and is now applying the methodology to mining and development projects around the world.

Jan 1, 1998

By Ralph H. Cleland

GENERALLY speaking, the Industry lost ground in 1941 in its accident experience. Though the frequency of compensation accidents was but slightly higher than in the previous year and well below past experience, our fatality rate shot up to that obtaining in 1938, and the average cost per man employed was the highest for some time. The number of fatalities was 56 in 1941 as against 33 in 1940. The average cost of compensation per man employed was $34.25 in 1941 as against $28.43. There was but a slight increase in the number of men employed. Accident prevention efforts were maintained, as shown by our frequency, but our accidents were of a more serious nature. In a period of considerable labour turnover, with many new men entering the Industry, especially the base-metal division, and much mental distraction, we might well have expected a high rate of accidents. That this did not occur is a tribute to managers, supervisors, and workmen alike. We all regret the high fatality rate and one must consider why this occurred. So far as it is possible to determine, there is no apparent explanation. There were no disasters. The accidents occurred to the same class of work-men, both in respect to jobs and age groups, and from the same age-old causes that we all know so well. Luck is a big factor in the seriousness of an accident; the solution lies in preventing accidents, even first-aid cases. Generally speaking, if minor accidents do not occur, major accidents do not occur.

Jan 1, 1942

By D. E. G. Maschmeyer

The operation of the pilot plant for the S-C Copper Process during 1976 has provided the basic data for the design of a commercial-scale plant. This paper introduces the commercial aspects of the S-C Copper Process through the presentation of a process flow diagram, a schematic flow diagram and basic design parameters for 75,000 tonnes per year (tpy) copper rod production from chalcopyrite concentrate. Basic operating requirements are outlined and a preliminary estimate of operating and capital costs for a Western Canadian location are summarized. The results have been compared with a modern smelter/electrorefinery to highlight the advantages and disadvantages of these two alternatives and to show why the new S-C Copper Process technology should be of interest to the copper industry.

Jan 1, 1978

By K. Aziz

The solutions to unsteady-state gas flow in a radial system have been reviewed in order to aid in the interpretation of drawdown data. It has been the practice to evaluate the time and rate conversion constants, directly or indirectly, by using reservoir data. This paper presents a method of determining these constants from drawdown data. A simplified approach to the de-termination for the various boundary conditions is presented. An example of a problem which illustrates the use of this theory appears in the appendix. UNSTEADY-STATE FLOW EQUATION The solution of any unsteady-state flow problem involves (1) the continuity equation, (2) the equation of state of the fluid, (3) the equation of fluid motion and (4) the boundary conditions. For the Darcy flow of a gas in the horizontal radial plane, the equation is when the viscosity, compressibility and permeability to gas flow may be assumed constant and the medium

Jan 1, 1963

By Dale C. H. Nevison

One of the most intensive of material rivalries is the confrontation between zinc die castings and plastic injection moldings. Pressed hard by the plastics industry, zinc die casters are learning how to make parts with less material yet without sacrificing quality. The key to this new trend is the technique of Thin Wall die casting. The obvious benefits of Thin Wall are lighter weight and lower cost. Again, obviously, these are the very selling points that put plastics into many appliance and automotive parts formerly made of zinc. One of the factors that has been most conducive to the outstanding growth of plastics has been the increasingly prevalent concept that "adequate" properties are sufficient, especially if there are cost advantages. Most of modern design today is oriented around the reasonable life of a product, rather than indefinitely extended life. This is simply an acknowledgment of the existence of a design environment that pervades many areas, reflecting the life-cyclic desire for change. Too often, so-called "weight-saving" materials end up being very costly - not only in production, but in durability and dependability. Change for the sake of change usually doesn't effect a change for the better. In the majority of cases, the best bet is to design in traditional materials and minimize the material needed, while maximizing the efficiency of the production process. Component prices of products to be produced from either plastics or zinc must be studied in detail to determine which material will produce the lowest cost of manufacture. It is not uncommon for two parts, similar in appearance at a casual look, to have a considerable difference in energy requirements and production costs. Detailed cost estimates of the advantages of each material should therefore be prepared for zinc and plastic parts before the final design and material selection decisions are made.

Jan 1, 1978

By Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"In natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the content of MoO3 varies from 2% to 10%. As a result, the flotability of seyrigite (scheelite with molybdenum) turns to be weaker. One seyrigite mine, which has been built for 3 years,still could not produce qualified seyrigite concentrate due to the weak flotability of seyrigite (Mo-bearing scheelite) in raw ore. In our experimental research, through adopting new seyrigite collector TA-3 and advanced mineral processing technology, the seyrigite concentrate with a grade of 65.62% WO3 at a recovery of 87.47% was obtained for the raw ore containing 0.19% WO3 and 0.074% Mo. By applying the new technical achievement, for the raw ore containing 0.272% WO3, the seyrigite concentrate assaying 68.03% WO3 with a recovery of 77.56% was obtained in industrial production.INTRODUCTIONIn natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the scheelite is changed to be seyrigite (Ca[(W,Mo)O4]) (Ma, Bian, & Wang, 2013). The content of MoO3 in seyrigite varies from 2% to 10% usually, the content of MoO3 in some of the seyrigite even reaches 34%. The flotability of seyrigite is weak (Zhang, 2007), and the seyrigite is difficult to be recovered by flotation with common collectors and regulators. One scheelite mine in Anhui China, which is a skarn type seyrigite mine, has not produced qualified concentrate yet since 3 years it has been built due to the limit of beneficiation technology. Therefore, it is necessary to conduct research on the collectors with high efficiency and developing advanced processing flow for this kind of ore."

Jan 1, 2016

By P. E. Cavanagh

Introduction A comprehensive study of the economics of processes for smelting iron ores has been made by the Ontario Research Foundation on behalf of the Ontario Research Commission. This survey has included investigations of all processes in commercial use, and proposed processes which are still in the experimental stage. The two main objects of this work were to discover (l) whether any known processes would be particularly suited to present and future Canadian conditions, and (2) whether any new process would be of assistance in solving the present scrap shortage in Canada. The future prospects of the Canadian iron smelting industry have changed radically in the past ten years. For nearly twenty years before 1939 no iron ore was mined in Canada. The ore used was imported, mainly from the United States and Newfoundland. The economics of iron blast-furnace smelting always force the location of blast furnaces near the source of coal for making high-grade metallurgical coke, and near the market for iron and steel, rather than near the iron ore. Blast-furnace installations in Canada are confined to the north shores of the Great Lakes with ready access to United States coal and ore and the major Canadian markets, and to Nova Scotia near the coalfields of that Province. This distribution of primary smelting capacity naturally results in relatively high prices for iron and steel in the West, the North, and in Quebec.

Jan 1, 1948

By H S. Ellis

Flow studies have been conducted on nickel-water suspensions in a 1in.-diam., 42-ft.-long transparent lab-oratory pipeline at concentrations of up to 25 per cent, by volume, and slurry velocities of up to 15 ft/sec. The average size of the nickel powder was approximately 150 mesh (106J.L). Three flow regime were noted. At the highest velocities, i.e., above 10 ft/;sec., where the concentration distribution through the vertical diameter was most uniform, pressure gradients could be correlated with the Durand-Condolios equation (7,8). An intermediate region, i.e., from 7 ft/sec. to10 ft/sec., could be distinguished, the lower velocity limit being that at which nickel particles began to deposit. This region was also marked by decreasing pressure gradients, for a given concentration, as the velocity was reduced. The upper velocity limit in this region was also uniquely defined in that the friction factor for any nickel concentration was the same as that for water. In the third regime, below about 7 ft/sec

Jan 1, 1963

By K. Morin, C. -Y. Hon, G. Lachapelle

"Air-sampling results suggest drill operators working inside environmental drilling cabs at an open-pit gold mine in Nunavut, Canada, are at risk of exposure to asbestos and silica (quartz). The authors installed RESPA® CF Vortex HyperFLOW® units, which showed promising results under laboratory conditions. The goal was to evaluate the effectiveness of these units under actual working conditions. Personal and area air sampling was conducted in drilling cabs with and without the unit and a Wilcoxon rank-sum test was performed to compare the results. Particulate concentrations were significantly lower in drill cabs with a unit installed than in those without.RÉSUMÉ Selon les résultats d’une campagne d’échantillonnage de l’air, les foreurs travaillant dans des cabines de forage environnemental dans une mine d’or à ciel ouvert du Nunavut, au Canada, risquent d’être exposés à l’amiante et la silice (sous forme de quartz). Les auteurs ont installé des unités RESPA® CF Vortex HyperFLOW®, lesquelles of frent des résultats prometteurs en laboratoire. L’objectif est d’évaluer l’efficacité de ces unités dans des conditions de travail réelles. Des échantillons de l’air inhalé par le personnel et dans les aires de travail ont été évalués dans des cabines de foreuses équipées ou non de cette unité ; un test de Wilcoxon (également appelé test de la somme des rangs de Wilcoxon) a été mené afin de comparer les résultats. Les concentrations particulaires étaient considérablement plus faibles dans les cabines de foreuses équipées d’une unité que dans celles en étant dépourvues.INTRODUCTIONGenerally, mining operations are associated with a variety of occupational hazards. In an open-pit gold mine in Nunavut, Canada, drill operators are routinely exposed to asbestos (primarily amosite) and silica (quartz)—two naturally occurring substances in the ore that is to be drilled (Table 1). Inhalation is the primary route of exposure for these two hazards, which are associated with respiratory health effects such as asbestosis and silicosis, respectively. In addition, asbestos and silica are classified as human carcinogens by the International Agency for Research in Cancer (2001, 2011). Given the toxicity of these two agents, it is imperative that precautions be taken to minimize the risk of exposure of the mine’s workforce. To address this matter, the mine has an exposure-control plan, which includes the provision of personal protective equipment, personal hygiene facilities, training, and a medical surveillance program. Furthermore, the mine performs occupational exposure assessments or air sampling on a regular basis because the morphology of the ore changes rapidly with respect to asbestos and silica content."

Jan 1, 2017

"IntroductionIn the 1970s, environmental concerns and associated liabilities were a new and unknown aspect of corporate risk. Today, social concerns and the associated conflicts that they can generate constitute a rapidly expanding aspect of risk. Although not a new phenomena — the Bougainville copper mine was forced into closure in 1988 — social risk has emerged as considerably more important, and increasingly visible, in the last few years. Social risk is now an aspect of all mining activities which needs to be calculated into project assessments, and to be managed throughout the life of a project. While social risk has a number of aspects at the corporate level, such as company image and shareholder relations, at the level of the individual project, its primary component is social acceptability, and the principal tool for managing it is the Social Licence to Operate.Social Risk in Latin AmericaThroughout Latin America there are newly modernized mineral codes and economic systems introduced over the last ten years which, together with new environmental legislation, look very much like regulations in developed countries. To the corporations, the existence of these instruments means that the risks from the environmental issues associated with the project are known; they are legislated, defined, quantifiable and hence manageable.It seems ironic that, just when comprehensive regulations for the environmental management of mining have been put in place throughout Latin America, there arise an increasing number of challenges to mining activities. For, in spite of the apparent guarantees provided by these new legislative reforms, communities in Latin America today are more frequently standing up and taking exception to the presence of mining companies, or the ways in which the companies are conducting themselves. The viability of projects becomes threatened because they are considered socially unacceptable, a phenomenon that we describe as social risk. These challenges are less about opposing mining activities than many people would think. Rather, they are based on an increasing desire on the part of the local population to have some measure of control over their own future, and to participate in the development process from the earliest stages."

Jan 1, 2000

By J. Pepin

When using alternating current submerged arc welding (SAW) to produce pipes from microalloyed linepipe steels, it is critical to balance penetration depth and deposition rates, in order to minimize the number of weld passes while still maintaining good heat affected zone (HAZ) microstructures and properties. A series of bead-on-plate (BOP) submerged arc welds were performed on X70 steel, using different waveform variable settings (i.e., balance, offset and frequency). Weld bead cross-section profile deposition and penetration areas were measured, and both Vickers hardness and Charpy V-notch impact testing were performed. Both single electrode and tandem electrode welds were evaluated.

Jan 1, 2011

By E. Lee Cameron

Summary Records of the past show that the first mineral production in what is now the Province of Manitoba consisted of salt, obtained about the year 1800 by the evaporation of brine. Also at an early time in our history, the Ordovician limestone at St. Andrews Locks, East Selkirk, and other localities was quarried for use as building scone in the construction of forts and fur trading posts. Both salt and building stone are still produced in Manitoba, although not from the original sources. In addition, there is now a substantial production of a variety of other industrial minerals and their products such as lime, crushed stone, gypsum, peat moss, and bentonite. The annual dollar value of production of the industrial mineral industry in Manitoba is today greater than at any time in our past and is derived from a greater variety of products. At the present time, exclusive of the various gravel pits operated by the Provincial Department of Public Works, twenty companies operating thirty-four separate pits, quarries, or mines are producing industrial mineral raw materials in Manitoba. This paper attempts to outline the development of the industry from its start about 1800 to the present, giving general information on the various materials produced. Some suggestions regarding the possibilities of establishing new industries based on other raw materials are given at the end of the paper.

Jan 1, 1949

By J. -C. Parisien-La Salle, D. Blais, G. P. Demopoulos

"In this work the dissolution, precipitation and adsorption behaviour of gold in acidic iron sulphate media containing small amounts of chloride ions is investigated via batch laboratory tests and OLI thermodynamic calculations over the temperature range 25-250°C. Chloride ions may be present in industrial pressure oxidation/pressure leaching (POX/PL) operations due to elevated water salinity levels or due to intentional addition as is the case of the CESL Copper Pressure Leaching Process. Thermodynamic calculations show that AuCl4 - may form depending on the free Cl-/Au ratio and temperature, its stability increasing with increasing Cl- concentration and decreasing with increasing temperature. On the other hand during POX/PL, we know that massive precipitation of iron in various hydrolysis products and compounds occurs. Hence of interest is the question how AuCl4 - that may form during leaching interacts with the iron precipitation products. Gold(III) chloride was found to co-precipitate with iron(III) (oxy) hydroxides and arsenates forming in the autoclave but not with natrojarosite. Upon further investigation it was discovered that activated carbon added in the autoclave (as done in CIL) acts as preferential sink for the mobilized gold, hence opening the potential for the development of a direct cyanide-free gold recovery process in acidic sulphate leach reactors.INTRODUCTIONThe recovery of gold from ores and concentrates has evolved over the years with processing routes becoming increasingly complex. Given the high value of gold, any reduction in losses during recovery operations constitutes an important economic benefit. One such loss that needs to be addressed is the potential solubilisation of gold during pressure oxidation (POX) of refractory sulphidic gold feedstocks. For example, Agnico Eagle Mines reported a loss in gold recovery due to the formation of a gold chloride complex (Garofalo, 2009). Gold is known to form complexes in solution, such as gold(III) chloride, if an excess of chloride ions are present. The fate of such soluble gold chloride during pressure oxidation and the subsequent neutralization of the acidic discharge slurry will determine if gold is lost or recovered in the downstream cyanidation operation. Thus it is of interest to know under what conditions gold chloride may stay soluble or co-precipitate along primary (formed in the autoclave) or secondary (formed during neutralization) precipitates. Furthermore, the mode of co-precipitated gold, such as adsorption on iron compounds, like goethite and hematite (Machesky et al., 1990; Nachayev, 1984); substitution in one of the precipitated phases; or finally chemical reduction to metallic state would have consequences in terms of gold recovery."

Jan 1, 2012

By X. Gu

Mining operations, especially surface coal mines, have great impacts on the local ecosystem and the environment. However, it has been a common practice in mine design that the economic evaluation considers only the operating and capital costs, while the costs incurred due to ecological damage are left out. Such practice underestimates the total cost of mining and ignores the difference in ecological impacts between different mine design alternatives. With growing interest in sustainable development, the mining industry is under increasing pressure to operate not only based on economic and engineering principles but also on principles of sustainability. Therefore, estimating ecological costs of mining and considering such costs in the mine design process is an important step towards reducing ecological impacts at the design stage. The objective of this paper is to quantify the ecological costs of open pit coal mining and to demonstrate the influence of such costs on the ultimate pit design. The ecological costs of mining are estimated based on the areas and types of land damaged by mining activities and the carbon emission from energy consumption. Four major components of ecological cost are identified, namely, lost value of direct eco-services, lost value of indirect eco-services, prevention and restoration costs, and the cost of carbon emission from energy consumption. Necessary equations are given for estimating these costs. An algorithm is described for ultimate pit optimization in coal deposits with near-horizontal coal seams. A case study is presented in which the ultimate pits with and without ecological costs are optimized and compared to show the influence of ecological costs on the pit design outcome.

Aug 1, 2013

By A. D. Hunt

THIS PAPER will review Canada's fossil fuel situation as we understand it today and indicate some of the options available to meet our energy requirements during the next 15 years. It would therefore be helpful to examine Canada's total energy requirements and discuss the un certainties of the data base on which we must base future energy investment decisions. On the world scene, Canada is at the top of the energy-consuming nations, using about 49 bbls of oil equivalent per caput/ year. This appears to be slightly ahead of the U.S. and of course much higher than that of many countries. It is generally accepted that there is a more or less direct relationship between energy consumption and material standard of living. However , as we know, Canada, when compared with other industrialized countries on a GNP, an individual-income or some other standard basis, is lower in the list. This situation may be explained by our more severe climate and a relatively small population distributed over a land mass second only to that of the Soviet Union.

Jan 1, 1977

By J. Keith Haddock

"IntroductionThe Bienfait Mine is operated by Bienfait Coal Company Ltd., one of the Luscar Limited group of companies. Situated 5 km southeast of the town of Bienfait, Saskatchewan, it can produce 2.0 million tonnes of lignite annually in addition to 158,000 tonnes of char from a carbonization plant located on the property. Geology The economically mineable coal seams of the Estevan area are found in the Ravenscrag Formation. The lignite-bearing sands, silts and clays were deposited in Early Tertiary age, in an inland sea centred in the Williston Basin of North Dakota. The top of the Ravenscrag is an erosional surface, overlain by Tertiary or Quarternary sands and gravels or glacial till. The regional structure is a gently plunging syncline which dips to the southeast at about 0.3 degrees. There are minor undulations in the Bienfait area which are due to differential subsidence during deposition. Sporadic faulting is probably a result of glacial pressures, and preglacial and glacial channels are responsible for washout zones and the abrupt irregular subcrop found in the area. There are two economic coal seams in the Bienfait area, an uppe; seam locally known as the Roche Percee, and a lower seam, the Estevan. Both seams have been extensively mined since lignite mining began in the area in the late 1800s. The Roche Percee remains only in a small portion of the Bienfait Mine and comprises a very minor portion of the reserves. It averages 1.74 m thick under 8.1 m of overburden. The till rests on top of the Roche Percee and due to weathering the seam is generally of poorer quality. The Estevan seam comprises the majority of reserves at Bienfait. The main seam which is being worked on consists of an upper bench averaging 2.75 m, a carbonaceous parting of 0.21 m, and a lower bench of 0.92 m. Overburden depth above this seam varies from 21.0 m to 38.0 m."

Jan 1, 1985