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The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By M. R. Khalesi, S. Bellec, C. Bazin, D. Hodouin

This paper proposes a classification model to predict the split coefficient of gold ore particles as a function of the particle size and gold content. The model is calibrated and validated using data obtained from the sampling of an industrial grinding circuit. Model calibration is based on a complete simulation of the circuit and involves parameters related to the gold grain distribution in the ore as well as a grinding and liberation model. Since cyanide is added into the studied grinding circuit, assumptions related to gold dissolution in the mills are made to allow simulation results which reflect industrial behaviour patterns.

Jan 1, 2011

By M. Girard, E. Bourricaudy, M. Ashbury, M. Canizares, A. Mezei

Liquid-solid separation and slurry handleability relate directly to commercial plant ramp-up success or lack thereof. The paper provides a well-proven approach for testing, scale-up and commercial application of difficult processes. Emphasis is placed on practical applications of rheological concepts developed both academically and empirically. The cause-effect relationship between the process chemistry and possible physical implications on the metallurgical plant operability is presented in a simple, direct form. Examples include recent results in areas of mineral processing and extractive metallurgy. Technical process risk factors and their mitigation are included in the discussion.

Jan 1, 2011

By M. R. Hudec, M. A. Nikolinakou, P. B. Flemings

"We model the shale response to the large deformations associated with salt bodies, and we identify the implications of the stress changes for hydrocarbon exploration. We employ both the static and evolutionary approach, and show that while the static one can model actual geologic geometries, only the evolutionary approach can provide a detailed description of the stress history of shales, which is essential for predicting stress, porosity, and pore pressure and, more generally, for understanding Earth processes related to salt-hydrocarbon systems.INTRODUCTIONDuring the last two decades, understanding the stress, material behavior, and pore pressure in shales around salt bodies has become increasingly important. The energy industry routinely drills near salt (Beltrão, Sombra, Lage, Fagundes Netto, & Henriques, 2009; Meyer, Zarra, Rains, Meltz, & Hall, 2005; Seymour, Rae, Peden, & Ormston, 1993), because a significant number of hydrocarbon reservoirs around the world are found in layers dipping away from salt diapirs.Salt is a viscous material that cannot sustain deviatoric stresses. Under differential loading it flows, changes shape, and eventually relaxes to an isostatic stress state (Urai & Spiers, 2007). Therefore, emplacement of a salt body and its viscous relaxation process may cause significant deformation of the surrounding sediments, perturb their state of stress and create local overpressures (Dusseault, Maury, Sanfilippo, & Santarelli, 2004; Seymour et al., 1993). As a result, drilling near salt is particularly challenging, and problems leading to additional expense or even abandonment are common (Bradley, 1978; Dusseault et al., 2004; Meyer et al., 2005; Seymour et al., 1993; Willson et al., 2003).Historically, salt and the evolution of its cross section to the present day geometry have been studied using kinematic restorations (Rowan & Ratliff, 2012). This approach aims to explain the present geologic section through a sequence of plausible past sections; however, it does not model the constitutive response of the wall rocks, hence it cannot provide any prediction on their state of stress. Similarly, largestrain numerical studies (Albertz & Beaumont, 2010; Chemia, Schmeling, & Koyi, 2009; Goteti, Ings, & Beaumont, 2012; Gradmann, Beaumont, & Albertz, 2009) have focused on the rheological evolution of salt systems without modeling the geomechanical response of the sediments."

Jan 1, 2015

By Davood Moradkhani, Maryam Rasouli

"The present study reports solvent extraction and separation of zinc from concentrated nickel sulfate solution. In our previous study, Zn and Cd in cold filter cake (CFC, 45-55% Zn, 11-16% Cd, and 2.5-4% Ni) were extracted by alkaline leaching followed by electrowinning processes respectively. The strip solution from electrowinning process, was a pregnant liquor solution (PLS) containing 16.8 g/l Ni and 4.2 g/l Zn. In this work, PLS is subjected to the solvent extraction process for separation of traces of Zn from high grade nickel. The zinc free raffinate containing 16.6 g/l Ni sulfate solution will flow to nickel electrowinning plant for cathode production. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) is the organic phase used in this study. The effects of various parameters such as organic phase concentration (10- 40 % v/v), pH (1.5-3), and temperature (25 and 45°) are investigated. Zinc over nickel separation factor increases by increasing pH from1.5 to 3. The results show that 98.7% of Zn was loaded at25°C O/A ratio of 1, pH 3, and 10% vol. D2EHPA. A 10 M NaOH is used for pH control. However, replacement of pH controlling agent with ammonia solution (25%. v/v) results in interesting observations. Ammonia addition, reduces the solubility of Ni2+ cations in solution. Nickel starts to precipitate from raffinate in a crystalline bluish-green form. The obtained crystals are characterized by XRF and identified to be nickel-bearing analog of boussingaultite, a rare sulfate mineral of nickel with chemical formula of Ni (NH4)2(SO4)2.6H2O. The crystallization rate of crystals is studied. It is a slow precipitation process with 75% in 4 days.INTRODUCTION Annually, many hydrometallurgical processes such as electrowinning, solvent extraction and leaching are applied to waste filter cakes in Zanjan, Iran. These additional processes on filter cakes are critical from both environmental and economic points of view. CFC (cold filter cake) is a toxic but valuable filter cake (45-55% Zn, 11-16% Cd, 2.5-4% Ni, and 0.2-1.5% Cu) produced in many zinc production plants. Our research group at Research and Engineering Company for Non-ferrous Metals (ReCo.), developed a series of hydrometallurgical methods for extraction of zinc, cadmium and nickel from CFC (Moradkhani, & Rasouli 2012). The recovery of zinc and cadmium with alkaline leaching and electrowinning was successfully studied. The strip sulfate solution from cadmium electrowinning unit, contains high concentration of nickel with some traces of zinc impurity. This pregnant liquor solution (PLS) was analyzed and reported to contain 16.8 g/l Ni and 4.2 g/l Zn. In this work, PLS is subjected to the solvent extraction process to separate Zn from nickel (Fig. 1). The organic phase stripping solution containing 4.2 g/l zinc and 200 ppm nickel can be circulated and used in the acidic leaching step. This generates nickel solution with high purity suitable for nickel cathode production."

Jan 1, 2017

By Peter C. Jones

Owing to the inadequacy of the ore transport system at Cassiar in the late 1960's, a new facility was required. This paper traces the various alternatives considered and gives a description of the tram line as installed. The problems encountered, changes made and future modifications are discussed in detail, together with the effects these have on maintenance and operations.

Jan 1, 1978

By T. R. Kostecki

"Instrumented rock bolts are effective tools for assessing the reinforcement and condition of immediate roofs; however, instrumentation can have relatively high costs, which can be justified by high reliability and repeatable and representative data measurements. The instrument’s durability and operational life are of great importance, along with accuracy, applicability, and usefulness. This paper develops reliability models for three instrumentation technologies used in slotted rebar, drawing data from studies at five underground coal mines. Three case studies demonstrate instrument applicability and usefulness. Finally, two types of instrumented rock bolts are used to determine the direction of bend and maximum bending strain. RÉSUMÉ Les boulons d’ancrage instrumentés sont des outils performants qui permettent d’évaluer la consolidation et la condition des toits immédiats. L’instrumentation peut cependant se révéler très onéreuse, des coûts qui se justifient par sa fiabilité élevée ainsi que par des mesures de données reproductibles et représentatives. La durabilité de l’instrument et sa durée de vie opérationnelle sont très importantes, de même que son exactitude, son applicabilité et son utilité. En s’appuyant sur des données issues d’études menées dans cinq mines de charbon souterraines, cet article développe des modèles de fiabilité pour trois technologies d’instrumentation utilisées pour des barres d’armature nervurées. Trois études de cas démontrent l’applicabilité de l’instrument et son utilité. Enfin, deux types de boulons d’ancrage instrumentés sont utilisés pour déterminer la direction de la flexion et la contrainte de flexion maximale.INTRODUCTION Using instrumented rock bolts to monitor strain changes in a rock bolt array allows engineers to understand the per-formance and effectiveness of the rock reinforcement system and the response of the rock mass to such support; however, instrumentation remains a niche solution for solving complex ground-control problems—particularly for underground coal mines, which is where they are needed most. From 2000 to 2016, fall-of-ground fatalities still accounted for an average of approximately 30% of the total annual underground coal mine fatalities in the United States alone (United States Department of Labor, 2018). These tools would also be useful for deep hard-rock mining conditions. The main reasons for the lack of widespread use are not only cost but also accuracy, applicability, implementation procedures, intrinsic permissibility, and reliability (Peng, 2015). As a result, measurements of coal mine roof behaviour using instrumented rock bolts are quite scarce, not widely published, or inadequately presented to provide a seamless understanding of a roof’s response to support."

Jan 1, 2018

By Côme Carbonneau

The ten -year case history of La Société Québécoise d'Exploration Minière (SOQUEM) is reviewed under the headings of the company's raison d'être, objectives, policies, structure and final goal. A brief analysis of its past operations is presented: aborted efforts, findings and developments. A projection is made of the future earnings, in terms of estimated present value, of its three main discoveries - Louvem , Niobec and Selim.

Jan 1, 1978

By D. J. Bowen

"Abstract -The Great Dyke extends for 540 km along strike, to unknown depth, and varies in width from 3 km to 11 km. Rb/Sr age determinations gives values of approximately 2470 Ma.The Dyke consists of a variety of mafic and ultramafic rocks, many altered to serpentinites. These include, from top to bottom, successions of gabbro/norites, pyroxenites, peridotites/harzburgites, and dunites/picrites.The layers dip in from either margin, steepest at the edges (20°) and flattening toward the central sections. Four separate complexes are present. From north to south these are termed the Musengezi, Hartley, Selukwe and Wedza Complexes, and are described as 'boat-shaped' or 'pig-troughed'. All are similar in petrological sequences. Physiographically, the Dyke is spectacular in the north, where as a mountain range it meets the Zambezi Escarpment. Elsewhere in the central parts there is little surface expression and wide open treeless vleis. Dyke rocks cut through granite and schist belt terrain and are termed 'The Magnesia Belt'.Vast mineral resources exist. These include chrome, asbestos, platinoids, nickel, copper and gold. Up to eleven chrome seams numbered from top to bottom occur in the lower ultramafic sequences. Seams are narrow at 10 cm to 30 cm but of high grade. The platinum occurs 10 m to 40 m below the norite/pyroxenite contact.A 60 m wide zone of Light Sulfide Mineralization (LSM) of Jess than 1% sulfides extends from the lower gabbronorites into the upper pyroxenites. In this LSM, four enriched zones carry up to 5% sulfides. The most widespread is termed the Main Sulfide Zone (MSZ), below which is No. 2, No. 3 and No. 4 Sulfide Zones. The MSZ carrying pyrite, pyrrhotite and chalcopyrite is a multi­ element ore with components of PGE (Pt-Pd-Rh), nickel, copper and cobalt, and gold and silver.Extensive exploration programs have been carried out and the intention is to begin large-scale mining. However, with Russia supplying metals to the western markets, South Africa's cutback on production, and an end to the Cold War, delays have arisen."

Jan 1, 1994

By Will S. Pettitt

Fracture Network Engineering (FNE) is the engineering design of rock mass disturbance through the use of advanced techniques to model fractured rock masses numerically, and then correlate field observations with simulated fractures generated within the models. Microseismic (MS) monitoring is a standard tool for evaluating the geometry and evolution of the fracture network induced during a hydraulic treatment, principally by source locating MS hypocenters and visualizing these with respect to the treatment volume and infrastructure (Figure 1). The integrated use of Synthetic Rock Mass (SRM) modeling of the hydrofracturing with Enhanced Microseismic Analysis (EMA) provides a feedback loop in which the SRM is constrained by the information provided by the MS data and the in-situ behavior of the fracture network is better understood, leading to informed decisions on future field operations. This paper discusses the technologies used in FNE and some of the developmental challenges we face in order to provide a more efficient and robust application of the approach. One particular challenge is the accurate representation of MS source data within the models (locations, magnitudes and mechanisms), and the ability to correlate these data effectively with field results. This challenge is being overcome by the development of more efficient numerical modeling algorithms, providing simulations in three dimensions at reservoir scale, combined with validation of these algorithms using laboratory and field case studies.

Jun 1, 2012

By R. M. BUCHANAN

The segment of Canadian industry based on smelting of alum in um and manufacture of consumer products is based entirely on imported alumina and bauxite. In the absence of Canadian bauxite deposits, consideration of anorthosite, a less desirable aluminous rock, is being undertaken as one alternative in maintaining assurance of supply. Anorthosites in Canada cover many thousands of square kilometres of the Precambrian Shield. Although compositions vary widely among Canadian anorthosites, many appear to exceed the specified minimum of 25% A I 20 3 in bodies containing more than the required JOO million tonnes. A lthough most Canadian anorthosites are of Precambrian age, one located in British Columbia has been identified as being Middle _Cretaceous.

Jan 1, 1984

By W. E. Oching, M. M. Ghomshei

Attracting and retaining workers in mining industry has become an uphill battle to many mining companies. As workers with significant experience retire, it is getting more difficult to attract not only new workers but also top talent to the mining industry to replace professionals exiting the workforce. To make matters worse, students’ enrolment in the post-secondary mining programs in Canada and USA is continuously declining year after year for reasons not directly linked to job market. This raises a question of how can the future needs of mining be met? This paper focuses on avenues for collaboration of industry and educational institutions to meet the current and future needs of mining. It provides effective approaches that mining institutes can engage with program advisory committees, role of the mining industry in supporting both faculty and students, how to harness the benefits of diverse workforce in the country and use of innovative technologies to attract young workers in mining. This work presents Human Resources (HR) professionals with tools that they can use to hire and retain skilled workers with strong interest to work in the mining industry. It also provides HR professionals with an opportunity to re-evaluate their restructuring practices during economic downturns as they reduce number of employees on temporary or permanent basis. The paper stresses the need of working together of the mining stakeholders including mining industry, academic institutions, First Nations’ communities and provincial(state) and federal governments to meet the current and future demands of mining as the industry experiences shortage of labour and low students’ enrolment in post-secondary mining programs. It is shown that mining educational institutes can enhance their programs and recruitments through establishing a better communication with all stakeholders. This communication can be facilitated by creating a national advisory board, to work with all mining programs at the national level for sustainable mining.

Jan 1, 2023

By F Kelly

"A central composite experimental design was used to determine empirical relationships between the operating variables of a ball mill and the characteristics of the ground products. The independent variables selected for the study were the work index and size distribution of the feed material, the feed rate and the pulp density. The measured responses included product size distribution, product surface area, viscosity of pulp discharge, weight of dry solids in mill, mill time constant and emitted sonic vibrations. The ball mill was operated continuously in open circuit during each experimental run.Multivariable regression techniques were used to derive linear empirical models from the experimental results. Of the four factors studied, the grindability of the feed material significantly affected every measured response. The size distribution of the ground product was affected significantly by the feed rate and the size distribution of the feed, but not by the pulp• density. Feed throughput capacity and pulp density were significant to the viscosity of the pulp discharge, the weight of solids in the mill and the mill time constant. Significant first-and second-order models are given for the above relationships. The relation-ships between the characteristics of the sonic vibrations of the operating mill and the various dependent variables have not as yet been established."

Jan 1, 1970

By A. A. Levinson, M. B. Kirkley, J. J. Gurney

"Scientific advances in the past decade have greatly clarified our understanding of certain concepts relating to the age and origin of diamonds. These advances are largely the result of geochemical studies of mineral inclusions in diamonds, made possible by modem analytical techniques which enable the accurate chemical analysis of micro-sized particles of the order of 200 microns in maximum dimension. As a generalization, the inclusions indicate that most diamonds formed from either of two rock types, peridotite and eclogite. Peridotitic diamonds have yielded ages of 3300 million years, whereas eclogitic diamonds areyounger and rangein agefrom approximately 1000to 1600million years. Kimberlite and lamproite, the two rock types usually associated with diamonds, typically are much younger than the diamonds they contain. Thus, it is now dear that kimberlites and lamproites are only the transporting mechanisms which brought diamonds to the surface and are in no way related to the formation of most diamonds. The latest concepts which developed during the past decade regarding the sources of carbon for the crystallization of diamonds from peridotite and eclogite, and the mechanisms of kimberlite and lamproite emplacement, IntroductionThe decade of the 1980s has seen major advances in our understanding of the age, origin and emplacement of diamonds. The information presented herein is applicable to virtually all natural diamonds, excluding diamonds related to meteorite impacts. There is still some question, however, as to the applicability of the new information to industrial grade ""fibrous"" or ""coated"" diamonds, and to microdiamonds (< 1 mm). In addition to drawing upon our own experiences, this review is summarized from a voluminous literature and for those interested in the original sources we recommend the books by Mitchell and Bergman (1991), Ross (1989), Nixon (1987), Mitchell (1986), Glover and Harris (1984) and Dawson (1980), and the review articles by Mitchell (1991), Gurney (1989) and Meyer (1985).are also discussed."

Jan 1, 1992

By A. Karzhau, B. Aldamzharov, Y. Tussupbekov

"This case study produced for the metal mine operating in Kazakhstan, which has ventilation controlled manually and working continuously at maximum speed to keep air flowing through each part of the mine 24 hours a day. The mine auxiliary ventilation has been designed with the maximum length of ducting systems with extra air volumes to compensate for potential leakage. The mine provided auxiliary ventilation to all production stopes even to those, which for various operating reasons become temporarily inactive. However, mine safety has to consider risks associated with the deficit of fresh air for mine gases dilution and removal. The mine needs additional investments for re-designing ventilation network and therefore needs to estimate financial risks associated with it. The aim of this study is to conduct risk analysis for ventilation network optimisation processes at the operational metal mine in Kazakhstan. Mine ventilation surveys were undertaken for validation of the computerised ventilation model. The mine ventilation network modelling has been undertaken to be compliant with Kazakhstan mining regulations. Results of the mine ventilation optimisation processes were analysed in terms of financial risks for investments into reconstruction of the ventilation shafts, extension of the ventilation network, variable speed fans and automated regulators. Savings were resulted from improving ventilation system efficiency by reduce airflow in areas without mining activity and redistributing existing ventilation capacity. Based on savings derived from the optimised ventilation network an additional NPV has been received. Stochastic modelling use Monte Carlo simulation producing representation of possible outcomes for the additional NPV considering electricity pricing as a major variability. As result probability distribution for the optimised ventilation network demonstrates the additional NPV in a range of 1.6 - 2.2 million US$ in the corresponding defined value of 90%. Moreover, there is only 5% chance that the additional NPV to be less than 1.5 million US$. Conducted risk analysis for ventilation network optimisation processes gives considerations on volume of investments into the mine ventilation system.INTRODUCTIONCosts for mine ventilation are typically increasing when mines expand to deep levels. Some underground mines in Kazakhstan still use continuously operating fans at its maximum capacity. This is not helping to save energy and costs that are in many cases very significant. This case study produced for the metal mine operating in Kazakhstan, which has ventilation controlled manually and working continuously at maximum speed to keep air flowing through each part of a mine 24 hours a day. The mine auxiliary ventilation has been designed with maximum length of ducting systems and extra air volumes to compensate for potential leakage. The mine provided auxiliary ventilation to all production stopes even to those, which for various operating reasons become temporarily inactive. However, mine safety has to consider risks associated with the deficit of fresh air for mine gases dilution and removal from the mine workings (Sabanov, 2019). The mine needs additional investments for re-designing ventilation networks and therefore need to estimate financial risks associated with it. The aim of this study is to conduct risk analysis for ventilation networks optimisation processes at the operational mine in Kazakhstan. Mine ventilation surveys for validation of the computerised ventilation model have been undertaken"

Jan 1, 2019

Current AG and SAG mill circuits have continued the trend to larger, fewer mills. These large mills place a significant additional load on the discharge systems and it has become imperative that the designs of these mill discharge systems are evaluated carefully to ensure maximum efficiency and have the capacity to be able to handle the increased mill discharge volumes. The current generation of multiphysics modeling tools allow a detailed analysis of AG and SAG mill discharge performance. The combination of Discrete Element Method modeling and Computational Fluid Dynamics allows the designer to model in detail all aspects of a mill discharge performance. This includes a detailed description of the build-up of solids and slurry in a mill discharge, the recycle of material back into the mill through the grates, the relative wear rates and the occurrence of overloading at the pinch points. These tools allow intelligent decisions to be made regarding the type of discharge arrangement, pan lifter geometry, and discharge cone design, so as to ensure that the discharge is capable of handling the duties required for a specific installation. This paper details the current state of the art in these modeling tools, and provides an overview of some recent applications.

Jan 1, 2012

IN 1932, the No. 4 shaft at Wright-Hargreaves mine was completed to a depth of 4,000 feet, and the lowest operating level at that time was at 3,900 feet. It was realized that the existing pumping system, using triplex plunger pumps at somewhat irregular depths in the mine, would be in-adequate to take care of the increasing volume of water that would have to be handled as mining operations expanded. Accordingly, in February, 1932, after a thorough study of the whole matter, it was decided to instal an entirely new, automatically controlled, system of pumping, employing centrifugal pumps, with their characteristically trouble-free performance, operated by off-peak power.

Jan 1, 1939

By H. W. Kasaini, E. Bourricaudy, T. Larochelle

Rare Element Resources Inc., a U.S. based company, has developed a three-stage process for producing a +98% mixed REO powder from hard rock feedstock (-48 mesh, 2.9-4.8% REO) consisting of bastnaesite and ancylite minerals. Firstly, the whole ore is digested in chloride media at low temperature in counter-current flow mode. Secondly, the rare earths (REEs) are selectively precipitated as oxalates directly from an impure pregnant leach solution (PLS). Finally, significant amounts of free acid and water are recovered from the REE-depleted filtrate and subsequently recycled within the process. Excess heat from the oxalate calcination process is captured and reused in the plant. Due to the low leach temperature (45 ºC) and moderate acid dosage (240-297 kg/t, HCl), rare earth oxides (REOs) are preferentially leached out of fine solids leaving most of the base metals (Ba, Fe, and Al ) in the residue. Selective recovery of REEs from the PLS is achieved by mixing dilute oxalic acid (33% H2C2O4) and PLS at elevated temperature (85-95 ºC). The REEs plus thorium are precipitated as oxalates (REE2 (C2O4).xH2O) while the base metals are left behind in the barren filtrate. Multiple batch and pilot test results have confirmed that 50-80% of the oxalic acid can be recovered from the REE-depleted PLS through low-temperature crystallization (10-15 ºC). Typical leach efficiencies of critical rare earths at 45 ºC range from 85-99% (average 93%) while oxalate precipitation at high temperature increases the crystal size of RE oxalates (>450 microns, d80) thereby improving filtration. The economic benefits of this process include elimination of flotation and magnetic separation Capex and driving hydrometallurgical Opex down to $6- 7/kg, REO produced. As part of a comprehensive risk mitigation strategy, Rare Element Resources Inc has operated multiple pilot plants at SGS in Lakefield, Ontario, Canada to optimize counter-current leaching (CCL), REE oxalate precipitation (OXP), and thorium removal circuits. This paper presents pilot testing data from CCL and REE OXP circuits.

Jan 1, 2016

By W. Hrynewich

"The Central Canada Potash facility, a division of Noranda Metal Industries Limited, is located 3 kilometres south of the junction of Highways 16 and 2, about 75 kilometres south-east of Saskatoon, Saskatchewan. The site occupies 26~ hectares of land and includes well-equipped machine and electrical _shops, a 325,000-tonne muriate storage and reclaim warehouse, a stores warehouse, processing plant (mill), two mine shafts (one for production, the other for servicing and personnel transport), as well as a two track product loading complex. Access to the site is by road and railway (CN and CP Rail). Suppliers of operating and maintenance use both means of transportation, whereas muriate shipments are entirely by railway.Currently five continuous mining machines - one a Goodman 526 borer and four Marietta 911-A units produce some 10,500 tonnes of ore per operating day. A smaller Voest-Alpine Af.1-100 boom type miner is used for floor cutting which was previously done by a production unit. In order to maintain safe, competent ground conditions only 35 percent of the total ore is extracted. At this rate mine reserves are deemed adequate for about 100 years. The plant has operated since August 1969 and has a current practical annual capacity of 1,270,000 tonnes of muriate. As of June 30, 1981, some 11.9 million tonnes of muriate had been produced from 31.4 million tonnes of ore. Of the total muriate, 6.1 million tonnes was granular, 4.8 million was coarse, and 1.0 million was standard. No standard product has been made since August 1978."

Jan 1, 1982

By J K. Irwin

The authors discuss the application of drum and friction hoists under modern conditions and give four examples of friction hoists proposed for various applications. The paper concludes with a summary of the advantages and limitations of friction hoists relative to drum hoists. Introduction T H~ introduction of the multiple-rope friction hoist m the late 1940&apos;s has complicated the se-lection of the right hoist for a given job. Once such considerations as rope safety factor, drum to rope ratio, hoisting distance, tons per hour and/or service duty have been decided upon, the selection of a drum hoist is relatively simple. We now ask our-selves "which hoist -drum or friction? (See Figure 1 and Figure 2). When a friction hoist is a possibility we are immediately concerned with how many ropes to use, whether to hoist balanced or counter-balanced, whether a friction hoist will be flexible enough for the application and, of course, what the relative costs will be.

Jan 1, 1964