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By A. MacKinnon, P. W. Kingston, W. F. Caley

"Wollastonite (CaSiO3]) is experiencing increased usage in a variety of applications, such as fillers in paints, plastics and resins, as an extender to replace both non-fibrous and fibrous materials (e.g. asbestos), and in the glass and ceramics industries. Significant new deposits of wollastonite have been discovered in Marmora Township, about 175 km northeast of Toronto. The geological setting of these large-tonnage. High grade deposits has recently been investigated to assess the possibility of their development. A preliminary study of the chemistry, as well as the mineralogy of six occurrences is presented. Based upon this information, it is suggested that several of the deposits have an excellent development potential.INTRODUCTIONWollastonite is an anhydrous calcium metasilicate (CaSiO3), with a theoretical composition of 48.3% CaO and 51.7% SiO2; the calcium may be partially replaced by iron, manganese, magnesium, and strontium. Commonly associated minerals include diopside, tremolite, idocrase, grossularite andradite, quartz, and calcite. Wollastonite forms as a contact metamorphic mineral within impure limestone near intrusive bodies of granite, or other acidic rocks, as the result of metasomatism of calcareous sedimentary rocks, or by the crystallization of certain magmas (e.g. carbonautes). Generally, the reaction of calcite with silica to produce wollastonite occurs when siliceous hydrothermal fluids from a granitic intrusion or primary silica in the limestone/marble react with calcite in limestone at temperatures between 450°C and 600°C."

Jan 1, 1989

By J. M. Beeckmans, S. G. Butcher, M. Goransson

"The counter-current fluidized cascade is a novel and potentially efficient pneumatic gravity separation device. Data are presented on over 150 runs of cleaning Alberta thermal coals, covering several size ranges. The coarser sizes of coal were processed in admixture with a fluidizing medium consisting of 0.5-by 0.1-mm hematite (or magnetite) and limestone particles. The partition curves for coal particles larger than about 3 mm, mixed with fluidizing medium, showed that the sharpness of separation achievable with the cascade approaches that of wet heavy medium processes, whereas with particles in the size range of 3 by 0.6 mm the sharpness of separation was comparable to that of a Baum jig. Useful cleaning was also achieved with particles smaller than 0.6 mm , Throughput rates of up to 11 tonnes per metre width of cascade per hour were achieved, with no indication of a deterioration in performance.IntroductionPneumatic coal beneficiation has steadily lost ground vis-a-vis hydraulic beneficiation during the past quarter century, primarily because of the sharper separations achievable with the latter methods. Nevertheless, there are certain inherent advantages of pneumatic separation methods which would give them an advantage in the market place were it possible to increase their efficiency to be technically competitive with those of hydraulic processes. These advantages are a dry product, resulting in a higher calorific value per ton, and avoidance of the problems associated with treatment and storage of process waste waters. Also, although it may be necessary to dry the raw coal prior to pneumatic processing, the dry rejects produced constitute an ideal fuel for a fluidized-bed combustor, which could provide heat both for drying the coal and for other purposes."

Jan 1, 1982

By Robert M. Hopkins, Craig C. Monahan

A corrosion survey was performed on ten selected H-piles which support a reinforced concrete wharf located at Trepassey, Newfoundland. Approximately 900 thickness measurements were taken at twelve different locations in each off our zones on the steel piles: the splash (atmospheric) zone, the intertidal zone, the low tide zone and the submerged zone. Results show that over the 2o-year life of the wharf, corrosion has been most severe in the splash, low tide and submerged zones with average corrosion rates for the flanges of 6.95, 9.45 and 6.86 mils per year (mpy}, respectively, and average corrosion rates for the webs of 5.13, 4.12 and 3.45 mpy, respectively. Minimal attack was found in the intertidal zone where the average corrosion rate was only 1.66 mpy on the flanges and 1.37 mpy on the webs. Such a pattern of attack is frequently observed f or steel piles partly submerged in seawater. The abnormally low corrosion rate associated with the intertidal zone is generally explained as being due to cathodic protection induced by the high corrosion rate in the adjacent low tide zone. Analysis of the corrosion data obtained for the Trepassey wharf would suggest that this explanation might be incorrect. An alternate hypothesis has been brought forward which better accounts for the extremely low corrosion rate observed in the intertidal zones of these piles.

Jan 1, 1990

By J. G. Schofield, R. C. Francki, K. M. Donaldson, F. E. Ham

"Developments in pyrometallurgical technology have led to larger furnaces operating under more intense process conditions. In order to maintain the reliability of these furnaces, which are frequently single-line units, the design of the refractories, cooling systems and bindings has become more critical. Traditional thermal and chemical requirements for the refractory to resist slag attack must still be carefully determined. The larger, modem furnaces have placed a new emphasis on the structural properties of the refractories as well as their thermal properties to suit the extensive cooling systems. Based on operating experience, supported by computer models, the refractories and bindings are designed to work together to accommodate the thermal expansions and contractions in order to minimize permanent furnace growth and the risks of leaks. IntroductionElectric furnaces are used extensively in smelting copper and nickel ores and concentrates. Laterite nickel ores and high-magnesia copper, nickel and platinum sulphide concentrates are smelted virtually exclusively in electric furnaces to accommodate the high melting point of the slags produced. Although a number of smelting processes using oxygen-enriched and/or preheated air have been developed to replace reverberatory furnace smelting of conventional copper and copper-nickel concentrates, (lnco, Noranda, Outokumpu, Mitsubishi) electric matte furnaces remain a strong process alternative for these concentrates, either as the primary smelting vessel or for cleaning the slags produced from these processes.The development of large, high-powered furnaces has been an important factor in the growth of electric smelting technology, as evidenced by the list of operating matte and ferronickel furnaces shown in Table I. Because the compressive forces required to maintain a tight, leak-free furnace increase with furnace dimensions, the selection and design of the furnace refractories, cooling systems and bindings require increased attention."

Jan 1, 1993

By Hajime Miki, Gde Pandhe Wisnu Suyantara, Ahmed Mohamed Elmahdy, Hidekazu Matsuoka, Kyushu University, Tsuyoshi Hirajima

"Selective flotation of chalcopyrite and molybdenite was studied using various surface treatment methods such as electrolysis, ozone treatment, and plasma. Oxidation via electrolysis method indicated that only chalcopyrite surface is affected by electrolysis due to conductivity difference with molybdenite. Oxidation treatments and XPS analyses indicated that chalcopyrite became hydrophilic due to deposition of oxidized iron on its surface. Various oxidizing methods also showed that chalcopyrite was selectively oxidized and this can apply selective flotation of chalcopyrite and molybdenite. The possible mechanisms are proposed in this work based on surface analyses and thermodynamic calculations.INTRODUCTIONCopper sulphide minerals often associate molybdenite (MoS2) which is one of the most important by-products (Wills, 2006). It is important to recover molybdenite perfectly not only since molybdenite is valuable mineral, but also contamination of molybdenite into copper concentrate or contamination of copper mineral into molybdenite concentrate indicates penalty for both concentrate values (Wills, 2006). Conventional separation of copper sulphide and molybdenite has been achieved with sulphide bulk flotation followed by selective molybdenite flotation with NaHS addition since NaHS works as a depressant for copper sulphide. However, this current process shows imperfect molybdenite recovery and depressant such as NaHS needs to be used under specific flotation plant since it might be environmental contaminant. Hirajima et al., (2014) have been studied selective flotation of molybdenite and chalcopyrite (CuFeS2), which is the most important copper mineral, with plasma pre-treatment. They reported that plasma pre-treatment process followed by washing treatment can improve molybdenite floatability and depress chalcopyrite. This result is attributed to surface oxidation and selective conversion of chalcopyrite and molybdenite wettability. It may be hypothesized that another surface oxidation methods could give a similar result as plasma treatment process. To test this hypothesis, in this study, as comprehensive study of oxidation effect, various oxidation methods such as electrolysis, ozone, and plasma were investigated. Electrochemical measurements, thermodynamic calculations to predict the chemical reactions happened during the process, various surface analyses, and flotation experiments were carried out."

Jan 1, 2016

By Trevor McGiddy

"Australia's prosperity relies significantly on income generated from exports of resources and agricultural products. In 1989-1990, coal was Australia's most valuable export commodity, contributing. A $5.7 billion or 14% of all export income.The abundance and quality of its coal resources and the proximity of Australia to the rapidly developing economies of Southeast Asia were significant factors that encouraged export-oriented growth and investment and will continue to do so. On the other hand, the 1980shighlighted the sensitivity of the industry to international changes in supply and demand, currency and socio-political forces.Following many years of disappointing returns for investors, mainly as a result of falling Australian dollar coal prices, resolve will be necessary to maintain competitiveness with resource-rich nations. In recent years, operators, unions and governments have begun to embark on a long overdue rationalization of domestic issues in a bid to increase productivity and reduce costs.The nature of mining operations is also changing; deeper surface mines and the growth of longwall mining will require the development of new technology and skills. Other challenges emerging from the international environmental debate will require that Australia responds appropriately to demands for cleaner fuels, energy efficiency and environmental responsibility.The future development of the Australian coal industry will therefore be influenced by its own ability to become more efficient and mature in the production of quality coal products and through rational international response to environmental questions."

Jan 1, 1992

By I. S. Thompson

A program of geochemical till prospecting, carried out by Derry, Michener & Booth in 1974, was instrumental in t~ e discovery of a copper deposit in Currie Township, Ontario, beneath thick lacustrine deposits of the Abitibi Clay Belt. The prospecting system involved the continuous collection of glacial sands and gravels beneath the clays, using a track-mounted, dual-tube rotary drill, and the separation and geochemical analysis of the heavy mineral content for Cu, Zn, Pb, Ag and Au. In one of 22 holes drilled down-ice from nine Canadian Nickel airborne EM conductors, fragments of chalcopyrite-bearing graphitic argillite, assaying 12% Cu, were recovered from a 14-foot gravel section beneath 83 feet of clay. Ultimately, mineralization was identified in 10 of 11 additional holes drilled up to 3,000 feet down-ice from the Currie deposit. The glacial fan, when compared to the 1,200- by 165-ft area of the subcropping mineralization, is at least 20 times the area of the deposit and is the result of glacio-fluvial reworking of the mineralized ground moraine. The Currie deposit is contained within a Keewatin succession of graphitic argillite, dacite tuff and graywacke, which is intruded by dacite and feldspar porphyry sills and dykes and truncated by a Keweenawan diabase dyke. Grade and thickness of the mineralization, which lies chiefly within the argillite, is related to felsic intrusives and hydrothermal alteration, and to fold hinges.

Jan 1, 1979

By Ward E. Kilby, Bruce I. Mcclymont

"Data from the South Fork Pit Area of the Bullmoose deposit in northeastern British Columbia are used to demonstrate the usefulness of microcomputers to the on-site geologist. The technique utilizes a series of digital surf aces in the form of a network of points to define various geologic parameters such as seam positions, topography and coal quality characteristics. Manual digitizing, kriging and combinations of these techniques are used to calculate these digital surfaces, the best method depending upon the type and quality of the data in question. Digital surfaces, each modelling a specific feature when combined and manipulated with the computer form a powerful tool, the deposit model. The resultant model, containing all the surfaces, is used to examine seam and inter-seam thicknesses, deposit volumetrics, seam quality characteristics and the adequacy of sampling.IntroductionCoal deposit modelling using computer-based techniques has become routine. However, a geologist working in the field, without access to mainframe or minicomputer, ha s considerable difficulty implementing these procedures. However, microcomputers, which are portable and inexpensive can handle exploration data, perform various geological analyses, and produce deposit models virtually at the same time as the data is being collected. For the on-site geologist this means that quick access to the results of such modelling could point out inadequacies in deposit definition and trends in coal quality deserving investigation."

Jan 1, 1985

By David L. Anderson

"The objective of this paper is to describe the potential impact of inter-provincial competition f or new output capacity on the Canadian potash industry. It will be shown that the ramifications of such actions are potentially severe, especially since the potash industry is one of the few non-fuel minerals in which Canada purportedly possesses a significant degree of market power. More specifically, the paper addresses the impact of possible expansions in New Brunswick, Manitoba and, perhaps, Saskatchewan. The findings suggest that such initiatives could result in substantial excess capacity and the dissipation of monopoly rents. In summary, given the market structure of the industry, it is unlikely that the employment and economic effects associated with industry expansion will offset the loss in national welfare attributable to rent dissipation.IntroductionThe objective of this paper is to discuss the potential impact of inter-provincial competition for new output capacity on the Canadian potash industry. The ramifications of such competition are potentially severe: given that the potash industry is one of the few non-fuel minerals in which we purportedly possess a significant degree of market power(1), it is important that sound supply management practices are followed. However, possible initiatives by New Brunswick, Manitoba and, perhaps, Saskatchewan may initiate an inter-provincial competition which could result in substantial excess capacity and the dissipation of economic rents(2). Given the market structure of the industry, it is not intuitively obvious that the employment and economic effects associated with industry expansion will offset the loss in national welfare attributable to rent dissipation."

Jan 1, 1985

By James E. Fisher, Roger Cotton

"The legal background f or environmental issues, and the growing emphasis both from government and private concerns of corporate and management liability for environmental problems provides one of the driving forces behind the growing concern with environmental law for the future. One prime objective must be the identification and minimization of potential liability, both for the corporation and its officers, directors and employees.This paper will identify the basis for liability of individuals and corporations for environmental matters, focussing on current legal requirements, and the appropriate legal response to events of such potential liability. It will also consider the reduction of liability through the implementation of management systems and environmental policies in order to ensure due diligence both with respect to corporate responsibility and the responsibility of the individuals within the corporation.IntroductionConsolidated Professor Mines Ltd . and its predecessor have been exploring in northwestern Ontario for about sixty years . During the last twenty years, the company has been interested in developing a gold mine, the Duport Project, on Stevens Island in Shoal Lake . The lake straddles the border between Ontario and Manitoba and is a drinking water supply for Winnipeg and environs.The Duport Project involves the mining of 450 t/day grading an average of 0.35 oz Ault of ore . At the minesite, located on Steven s Island in Shoal Lake, only preliminary processing of the ore will take place, to produce gravity and flotation concentrates for final gold recover y at a mainland plant well removed from the Shoal Lake watershed. No hazardous chemicals will be used at the island site."

Jan 1, 1991

By E. Busse, J. E. Burgener, J. G. Eacott, M. C. Robinson, P. E. Burgener

"This paper presents a preliminary assessment of the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from electric arc furnace baghouse dust at a mini-steelplant. Recent studies and literature are referenced briefly as they pertain to the formation and characterization of dust, toxicity considerations and alternative dust treatment and disposal options.Laboratory testwork results, published data, pilot plant experience and anticipated influences resulting from recycling residues are used for the purpose of developing a conceptual design for a caustic leach - electrowinning plant to treat 15,000 tonnes/year of dust at a one million tonnes /year capacity steelplant in Canada.Target economic studies, comprising preliminary estimates of capital and operating costs, revenues and rate of return are presented. Economic and commercial considerations concerning the relative merits of dust treatment at a centralized facility compared with an on-site plant are discussed.IntroductionThe treatment or disposal of mini-steelplant electric arc furnace (EAF) baghouse dust has been given increasing attention in recent years for two principal reasons. Firstly, the dust is now classed as a hazardous waste material under V.S. EPA regulations which prohibit its disposal in dumps other than controlled landfill sites. Secondly, the dust contains certain metal values, notably zinc and lead, which may be economically recoverable, depending on the costs associated with disposal resulting from enforcement of the EPA regulations. Other metallurgical dusts and waste materials, from both ferrous and non-ferrous operations, may require the same considerations as EAF baghouse dust.Several studies have been carried out to examine various aspects of dust treatment but few commercial plants are in operation. Technology employed uses pyrometallurgical techniques. Commercial-scale hydrometallurgical plants are not known to exist although small-scale plants are frequently more economically attractive than their pyrometallurgical counterparts which generally require economies of scale to be viable.The concentration of mini-steelplants in northeast V.S.A. and southeast Canada merits study to determine whether or not dust treatment for metals recovery is a commercially feasible alternative to disposal.This paper examines the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from EAF baghouse dust at an on-site ministeel plant processing carbon steel scrap and discusses economic and commercial considerations pertaining to dust treatment at a larger, centralized facility."

Jan 1, 1984

By Richard Samson

"RésuméComme l'exploitation d'un gisement à grande profondeur représente un défi de taille et que la profondeur à laquelle se situe celui d'Ansil varie de 1200 m à 1460 m, nous avons dû mettre en place une infrastructure de surface d'envergure incluant un treuil de production et un chevalement d'une très grande capacité. De même, l'infrastructure sous terre a été proposée en tenant compte de ce fait important; d'ailleurs, l'excavation de deux puits circulaires dont l'un est en beton et acier et l'autre exclusivement en béton en témoigne. De plus, la plupart des cheminées principales qui furent excavées sous terre sont de forme circulaire.L 'exploitation du gisement s'effectue par une méthode chantier ouvert (abattage par longs trous), remblaye immédiatement âpres avec un mélange de roche stérile et ciment. Un taux de minage de 1750 tonnes par jour est requis pour assurer la production.L 'utilisation d'une technologie de pointe tels: les ventilateurs et les portes de ventilation sous terre contrôlées de la surface, un système de relèves macroséismiques, de chargeuses-navettes contrôles à distance, en passant par le dessin et la planification assistes par ordinateur nous permet d'optimiser l'exploitation du gisement Ansil.IntroductionEtant donne la grande profondeur a laquelle le gisement Ansil se situe, no us avons à mettre en place une infrastructure souterraine et de surface d'envergure pour nous permettre d'atteindre nos objectifs d'exploitation.Infrastructure de surfaceLa mine Ansil dispose d'une infrastructure de surface d'importance possédant une grande capacité (Fig. I). Les deux facteurs qui furent déterminant pour le dimensionnement des infrastructures furent le taux d'extraction de 1990 t/jour et la profondeur a laquelle I 'exploitation s'effectue, puis que cette dernière affecte le temps de cycle et la capacité de hissage.La première composante principale de I 'infrastructure de surface est un treuil de production a 2 tambours de 3.65 m de diamètre et de 2.0 m de largeur chacun. Ce treuil de marque Fullerton, Hodgart & Barclay construit en 1970, opère avec 2 moteurs de 930 kW a une vitesse de 700 m/min. et il a une capacité maximale de 32000 kg. Deux câbles d'acier de 45 mm de diarnètre et de 160 000 kg de résistance a la rupture servant au hissage des bennes d'une capacité de 12 tonnes. De plus, un moteur/générateur de 3000 kW (M.G. Set) raccorde au treuil de production sert a stabliser son alimentation électrique."

Jan 1, 1991

By Jorgen Elbrond, Yve Lizotte

"A mine evaluation method based on the use of a computer program that models mining with an open-ended dynamic program is presented in this paper. It is demonstrated with an example how the method is applied, how some of the decision variables are related in the particular industrial environment and how these decision variables affect the economic benefits of mining.IntroductionTwo distinguishing characteristics make mining a particular industrial environment: exhaustible resources of a given ore deposit and heterogeneousness of the ore grade spatial distribution in the ore deposit. These characteristics, inflation, uncertainty and cyclical price variations which greatly affect estimated cash flows also contribute in rendering difficult the evaluation of the economic outcome of mining at the preliminary planning stage.Decision variables and their ranges are associated with the mine plan; basically, they include choices of the mine's nominal capacity (mining and milling), the sequencing of mining through the deposit, the ranges of possible production rates and cutoff grades, and the stockpiling policies. The mine's nominal capacity must be decided at the planning stage, but this capacity choice must take into account flexibility to modify other decision variables as mining commences and uncertainty resolves.Although it is generally accepted in discounted cash flow analysis that the sequence of mining must proceed from the richest to the lowest-grade stopes (with correspondingly ajusted cutoff grades), this may not produce optimum benefits when cyclical price variations are considered.Mining rates and cutoff grades can also be adjusted to changing economic conditions, taking into account the limited resources of the ore deposit. Thus, when prices are thought to be in the trough of a cycle, production can decrease to preserve ore for expected greater future profits. When prices rise, mining rates can increase possibly even over the mine's nominal capacity. In both cases, the machinery's effectiveness shall not be-optimally utilized; this will be reflected particularly by the variations in the concentrator's metal recovery and the concentrate grade output."

Jan 1, 1982

By Roland Froidevaux

"The main object of ore reserve classification is to assess the reliability of an ore reserve estimate. Because traditional classification schemes fail to provide a means of calculating this reliability, the terms 'proven "" 'probable' and 'possible ' ore were introduced as an attempt to qualify it.Geostatistics, on its part, allows the quantification of the precision of any ore estimate and thus appears as an appropriate tool for ore reserve classification.However, the problem of fixing quantitative boundaries for ore classes remains. In order to be meaningful, ore class limits based on the degree of reliability should be customized to the commodity, and the type and size of the deposit. In addition, the precision of an ore estimate will be affected by the cut-off grade and the size of selective mining units.IntroductionPrimarily, ore reserve classification should be seen as a communication tool between the geologist and the mining engineer on one hand and the management and policy maker on the other. By classifying ore reserves, the geologist tries to answer the very fundamental question: ""What quantity of metal is there in the ground and how sure am I that it really exists?""The difficult y of quantifying the degree of reliability of reserves has led to the creation of a large suite of terms and definitions, with almost every mining company having its own set of definition standards. As lower-grade deposits are brought into production, the margin of tolerable error in estimates of the grade and tonnage is becoming much narrower. Consequently, the need for unequivocal definition of the reliability of ore reserves is increasingly acute. Most of the generally accepted systems of classification, however, describe the reliability of reserves in qualitative, rather than quantitative, terms."

Jan 1, 1982

By W. Petruk, D. R. Morris

"The lead concentrate produced from the volcanogenic base metal ore of Brunswick Mining and Smelting in New Brunswick contains major to trace amounts of iron, zinc, cadmium, arsenic, antimony, copper, silver, selenium, tellurium, bismuth, sulphur, tin, indium, mercury and manganese as impurities. When the concentrate is sintered some of these impurities enter a variety of oxide phases, whereas others precipitate as metals. In the lead blast furnace the oxide phases decompose and the impurities recombine 10 form new phases, most are eventually discharged to the slag. The metals of the sinter remain as metals in the lead blast furnace where even more are produced, and are discharged largely with the lead bullion,IntroductionMany lead concentrates are produced from volcanogenic base metal ores . Such ores contain a wide variety of trace minerals and trace elements , therefore, concentrate s obtained from them will contain the trace elements as impurities . The impurities in the lead concentrate from one such ore, the Brunswick No. 12 deposit of Brunswick Mining and Smelting Corporation (BM S) in the Bathurst area in New Brunswick , were studied as pan of a larger investigation that was conducted to determine the extent of chemical reactions of the sinter within the lead blast furnace(1,2) The lead concentrate was investigated to identify the host mineral s for the impurities, the lead sinter was studied to identify the host phases, and frozen products from different depths within the BMS blast furnace at Belledune, New Brunswick were studied to determine the behaviour of the impurities.T he investigation was performed by pre pa ring polished sections o f the samples and studying them with a reflecting microscope, a scanning electron microscope (SE M) equipped with a Kevex energy dispersive X-ra y analysis system, a microprobe, and a Quantimet 720 image analyzer. The samples were also analyzed by X-ray diffractometer, and individual grains were analyzed by the Debye-Scherrer X-ray powder film method."

Jan 1, 1985

By J. Stachulak, M. Scobie

"This paper addresses the occurrence and indicated causes of conveyor fires in North American and European underground mines. Some significant convey or fires which have been experienced in recent years in Canadian hardrock mines are then reviewed. The nature of existing conveyor monitoring technology is considered in the context of such fire hazards. Experiences with new monitoring technology recently installed at several conveyor sites at Inca Ltd. mines are then reviewed.IntroductionFires associated with conveyors have long been recognized as a serious hazard in underground coal mines. Recently, however, there have been some significant conveyor fires in Canadian underground hardrock mines. These offer important evidence as to the nature and causes of potential hardrock mine fifes. They also warrant attention with a view to improving over-all mine design, ventilation and emergency preparedness.In addition, a new era in mine communications and monitoring technology has been entered which should offer improved capability to protect against such fires. This paper was motivated by the need to understand the causes and mechanisms of conveyor fires in order to improve their safety. This should be possible through implementing more effective monitoring systems, as well as improving conveyor design. Underground mines are becoming more intensively mechanized, with less human surveillance of equipment and a greater dependency on remote monitoring systems."

Jan 1, 1992

By I. R. Muirhead

"One approach to making new technology available is to demonstrate its value under full-scale operating conditions. Studies were undertaken to assess the feasibility of this approach to introducing a longwall mining system to the western Canadian coalfields.The longwall method of mining coal is described, world and Canadian usage is reviewed, and the merits of the system in comparison 10 other coal mining methods are discussed.The rationale for a longwall demonstration in western Canada is presented, along with a proposed organization for the design, operation and dissemination of the findings from such a trial. The factors which must be considered in the design of the demonstration, and in the assessment of a potential site are highlighted. It is concluded that a demonstration of this technology is both timely and essential to prepare the way for the western Canadian coal industry of future prospects for coal.IntroductionFor many years CANMET has encouraged research work organized on a cooperative basis. This requires that a working consensus must be negotiated by researchers and operators at the beginning of the project and continuously refined as work proceeds. The result is usually a more relevant selection of research problems, improved direct ion and con duct of experiment al work and often a validation phase in which research concepts are tested in an opera ting environment. All this tends to narrow the gap between obtaining research results and applying them.Even under the best of circumstances cooperative projects require a good deal of coordination and enthusiasm to maintain focus and the pace of work. The working perspective of a research scientist in a government laboratory is substantially different from that of a mine operator at a producing mine, and a common ground must be found. This is difficult to do and cooperative projects typically evolve over several years as experimental results progressively define the potential solutions to mining problems."

Jan 1, 1985

By L. C. Galloway, G. L. Tiley

"Mine hoist brakes must meet the following statutory performance criteria:- There should be two independent braking systems; at least one should act directly on the hoist drum.-If one brake fail s, the others should be able to retard and stop the hoist safely before the descending conveyance, carrying the rated load, reaches any obstruction.- When all brakes apply, decelerations should not be so violent that men travelling in the conveyance are injured.- The brakes shall not overheat and fade during an emergency stop.This paper discusses design principles and capacities of caliper and disc type brakes, when applied to double drum and friction hoists of equivalent capacity.IntroductionThis paper is about the brakes that are used on mine hoists; their functions, especially in emergencies, typical design, and how they are operated, controlled, tested, and adjusted.There are two basic types of mine hoists:1. Drum hoists, where the ropes are attached to, and coil on drums. The simplest system has only one drum. Most such hoists, however, have two drums, attached to a common shaft. Ropes are wound on each drum in opposite directions, so that when one conveyance is being raised, the other is lowered. The conveynaces may travel in vertical or inclined shafts. In the latter case, the hoist s are referred to as slope hoists.2. Friction hoist s, where the headropes are not attached to the wheel, but are in contact with it for an angle of lap of, typically, between 180 and 195 degree s. Forces are transmitted from the hoist wheel to the head ropes by friction.The lower ends of the conveyances are connected to balance ropes , approximately the same weight per foot as the headropes."

Jan 1, 1986

By B. J. Fryer, R. P. Taylor

"As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth element s (LREE), reflecting their high pH, low fluid/rock ratios, and the dominant role of CI- complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO, 2- become important in metal (e.g. Mo, W,) transport through complexing, and their activity in the hydro thermal fluids is illustrated by mobilization of the heavy rare earth elements (HREE).The relative involvement of CI- versus F - versus CO32- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F' and CO32- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geo chemistry, particularly when integrated with fluid inclusion and isotope studies, can provide (1) an effective method for identifying the physicochemical controls of metal transport and (2) a useful criterion for elucidating metal distribution."

Jan 1, 1983

By Jian Deng, Haitian Sun, Zengqian Hou, Shuhe Song

"Abstract - Volcanogenic massive sulfide (VMS) deposits, an important base-metal deposit type in China, occur widely in submarine volcanic districts of variable magmatic affinities. These VMS deposits range in age from Archean to Mesozoic, but most are in Proterozoic and Paleozoic sequences. More than 60% of VMS deposits formed in the Paleozoic, the most important metallogenic eon. Three important Paleozoic VMS-metallogenic provinces include Northern Qilian, Sanjiang and Altai provinces. The Proterozoic constitutes the next important era, but with no VMS deposits in the middle Proterozoic. VMS deposits associated with the Proterozoic volcanic rocks occur around the Yangtze Platform and in the western Kunlun-Qinling. The Triassic is third in importance, with VMS deposits concentrated in the Sanjiang Tethys. The Archean has only one VMS deposit, on the northern margin of the Sino-Korea Platform.Five distinct compositional classes of Chinese VMS deposits have been distinguished: Cu, Cu- Zn (or Zn-Cu), Cu-Fe, Zn-Pb-Cu, and Pb-Zn (-Cu). The Cu, Cu-Co, and Cu-Zn types of deposits occur sporadically from the Archean to Paleozoic, and are closely associated with mafic and ultramafic volcanic sequences. The Zn-Pb-Cu and some Cu-Zn type deposits are restricted to the Paleozoic and Triassic, and are hosted by calc-alkaline felsic rocks in bimodal basalt-rhyolite sequences, whereas Cu-Fe and Pb-Zn type (except for the Laochang deposit) deposits are restricted to the Proterozoic and occur in calc-alkaline volcanic sequences. As large quantities of marine mafic volcanic rocks were deposited in western China, Cu and Cu-Zn deposits are major types of Chinese VMS deposits.Chinese VMS deposits formed in a wide range of paleo-tectonic settings and depositional environments, such as island-arcs, rifts, aulacogens, and ocean ridge hot spots. Among these, the rift and back-arc environments are the most important, containing about 60% of Chinese VMS deposits. Aulacogens are a subordinate environment where most of the Proterozoic VMS deposits formed. The oceanic ridge and hot-spot systems are common in the tectono-magmatic domains in China, but contain only a few small Cu and Cu-Zn type VMS deposits.The Chinese VMS deposits have usually been influenced by both deformation and metamorphism to various degrees, resulting in changes in the shape and metal distribution. Seven representative deposit styles have been recognized: sheets, sheet plus strata-bound stringer, cyclically zoned deposits, mounds, mound-like deposits, strata-bound stringer-disseminated, and stockwork-disseminated deposits. The formation of these various styles of deposits is controlled by several key factors, such as lithology and permeability of the host rocks, focused or unfocused discharge, temperature and chemical composition (e.g., salinity) of hydrothermal fluids, as well as depth of seawater."

Jan 1, 1999