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By Harry Wilton-Clark

Introduction Coal cleaning may be taken as meaning the separation of coal-as-mined into two or more fractions. Coal cleaning includes coal washing, together with any other means used in the ultimate preparation of coal prior to shipment (as coal) . The method of coal cleaning devised for any given mine must be one which is based entirely on the economic results obtainable. The installation of a high-cost and complex washing plant, designed to produce a low-ash dean coal, at the highest possible recovery, may be unsound practice. A crude 'roughing' washer may be the best result of sound engineering and operating consideration, and in some cases coal cleaning should be confined entirely to preparation at the face. Consideration of complete costs, to the point where the coal is actually sold, may show that certain seams are workable or not workable. Of the seams found workable, extraction of the whole or parts of the seam may be decided on. The portion to be extracted may contain rock or bone partings, which must be removed. It may be good practice to mine the extra portion and remove the objectionable materials by surface washing; or it may be that such materials should be removed underground, even at an increased mining cost. For instance, in some of the steeply pitching seams of the Alberta Crow's Nest Pass district, the removal of bone and rock at the face may be almost impossible under the usual 'up the pitch' or 'angle' mining methods, but possible by mining across the pitch so that the material to be rejected can be removed and gobbed. Again, if a complete seam is being extracted, investigation may show marked differences between top coal and bench coal, and if sufficient mine cars are being loaded from a chute at one time, the fact that such a place is working top or bench coal at the time may be reflected by peaks in ash content or size proportions at the ripple. It may be very effective coal preparation to smooth out such peaks.

Jan 1, 1934

By Mike Dry, Rod Dry

If humanity is truly serious about reducing emissions of carbon dioxide into the atmosphere, today’s power plants burning fossil fuels will have to be replaced by power plants that do not emit CO₂. Unless carbon capture/sequestration becomes practical, the new power plants will be hydroelectric, wind, solar or nuclear installations. Hydroelectricity requires the appropriate geography. Solar installations can only deliver power as and when sunshine is available, and wind installations when the wind blows. Therefore, power from these sources will be intermittent, but the demand for electricity does not follow the patterns of sun and wind. That will require large-scale electricity storage and/or load following by the remaining power suppliers, increasingly so as the use of fossil fuelled power generation declines. Modern nuclear power plants are designed for demand following. However, operating at lower than design output has a negative impact on the economics of nuclear power plants because the overall cost of the electricity they generate is dominated by capital cost. Primary (blast furnace) iron smelting is responsible for a significant part of global CO₂ emissions because the reagent used is carbon. Were it available in sufficient quantity (and at a low enough cost), hydrogen could replace carbon in the manufacture of raw direct reduced iron (DRI), using technology such as modified HYL (Tenova Hyl, 2018) or Midrex (Ravenscroft, 2017). This paper examines a scenario in which, instead of demand following, nuclear power stations are operated at their design capacities and surplus power is used to generate hydrogen in off-peak periods. This hydrogen is then used to replace carbon in the manufacture of raw steel.

Jan 1, 2020

By D. H. Wilson

"This paper examines the increasing need for mechanical-electrical people within the industry and some of the reasons why such a shortfall exists. It is suggested that, in part, it is image related. The present industry-education relationship in addressing the situation is examined and some thoughts are expressed on how these may be built on, in order to help solve the problem of attracting people to this critical area.IntroductionAs a long-time proponent of plant engineering and maintenance as a management function, I would like to review the progress made by the industry/ educational approaches in satisfying the needs in that area. In doing so, I would like to make the following points:1) that there has been an accelerating shortfall of mechanical-electrical people relative to the needs of the industry;2) that the condition will probably get worse before it gets better; ,3) that the past industry I educational approaches to alleviate the problem have met with limited success; and finally4) I would like to review some of the things being done and consider how these efforts might be extended."

Jan 1, 1981

By Floyd Smith

Based on underground observations made in .the coal mines of the Dominion Coal Company Ltd., this paper deals with the stress phenomena in the approach roads and headways and in the gob areas associated with the longwall method of total extraction. The deformation of roadways during development and the deformation of roadways during the total extraction period is delineated and presented in graphical form .. Conclusions are made as to the feasibility of the introduction of the retreat method of longwall extraction in one of the colhenes. The importance of future studies are enumerated, especially. those pertaining to the determination .of the opti.m.um sizes of protective pillars and to increasing the efficiency of the current methods of artificial roadway support.

Jan 1, 1967

By T. K. Bose

According to the Intergovernmental Panel on Climate Change (IPCC), the average global temperature has risen over the last century. If this trend continues over the next century, the IPCC projects a significant increase in temperature and a rise in sea level. The changes in climate could adversely impact human health, agriculture, water resources and ecosystems. Most national and international agencies have concluded that our use of carbon-rich fuel is responsible for global warming through the greenhouse effect. In the future, the situation may get worse if the increased need for energy in countries like China, India and Brazil is fulfilled by burning fossil fuel. Advanced natural gas-fuelled vehicles have the potential to reduce carbon monoxide and reactive hydrocarbon emissions substantially compared to gasoline vehicles. Further environmental benefits can be realized by using a blend of natural gas and hydrogen. Such an approach will help create an infrastructure for an eventual transition to hydrogen.

Jan 1, 2005

DOME MINES, Limited, is a gold producer situated in the Porcupine area of Ontario, 500 miles north of Toronto. During the year 1960, '71 4,600 tons of ore were milled, yielding gold bullion valued at $6,025,370. Prior to conversion to natural gas, an average of 3,200 tons of coal was consumed annually, one third of which was obtained from Canadian sources with the remainder coming from the United States. Due to the distances involved, the freight charges increased the pithead cost by as much as ISO per cent. Steam is generated at a central boiler plant and used for timber treatment, plant heating and process steam. Until August, 1960, steam was supplied during the winter months by two water tube coal-fired boilers, each rated at 200 boiler horsepower at 100 per cent output. Steam requirement was as high as 150 per cent of boiler rating in the colder periods. The summer load was

Jan 1, 1962

By B. Kenney

For SOFCs, composite cathodes comprising an electronically conducting electro¬catalyst (e.g. LSM) and an conically conducting electrolyte material (e.g. YSZ) are considered to improve the electrochemical performance by extending the active reaction zone to regions beyond the electrolyte-electrode interface, as in the case of conventional cathodes. Interpretation of experimental data for composite cathodes, however, is complicated by the mixed conducting behaviour which results in local overpotential distributions throughout the composite cathode. These local overpotentials depend on many factors, such as the composition, particle size, porosity and thickness of the cathode. Reliable experimental data obtained from composite cathodes requires carefully crafted microstructural parameters in order to minimize the overpotential variations. A mathematical model of a composite cathode was developed using coupled differential equations describing transport and consumption of chemical species, oxygen ion and electrons. Simulations under various oxygen concentrations were used to obtain the reaction order of the oxygen reduction reaction. An apparent po2 dependency was then extracted from the predicted Rp vs P02 data. It was found that this p02 dependency can be significantly influenced by the micro-structural parameters of a composite cathode, primarily due to local overpotential distributions.

Jan 1, 2005

By O. A. Bascur

Several new hydrometallurgical plants have been built in the past years, new processes and equipment as well as advanced process control systems are being used to deal with the increasing requirements of safety, quality and production. Plant Information Management Systems are now being recognized as a key infrastructure component of the plant, giving the management, the operators, process engineers, finance, maintenance, and regulatory agencies an integrated view of the operation and providing the links for the (increasingly) multidisciplinary organization. This paper reviews several implementations of Plant Information Systems; real time performance management infrastructure examples are reviewed as a key component of business strategies, such as Mine to Port Planning and Supervision, Metallurgical Mass Balances, Solvent Extraction Composition Statistical Process Control, methods to minimize organic losses, reduce variable costs and to improve metal extraction. Several examples are provided to illustrate how companies are using the real time and historical information from assets and metallurgical processes to enable and empower people to improve the operations quality, safety and throughput, as well as continuous improvement and innovation initiatives.

Jan 1, 2007

By C. H. Tiernon

"This paper was' prepared to emphasize the part that coal washing tables can play in the development of many of the reserves of coking coals in Western Canada_ It covers a brief history of the development of the coal washing table through the present third-generation unit, which suspends from overhead steel beams and is driven by a counter-rotating gear mechanism. The design and operation of this unique table are covered in detail.An analysis of actual operating data is included, with explicit statistical breakdowns of the table products. The data used were actually produced by operating coal companies, and also produced by the United States Bureau of Mines while gathering data for a research investigation. Table feed capacity is discussed, as well as performance criteria and the parameters of relative table performance. Several typical table flowsheets are described, emphasizing the specific reasons for their use. The paper covers the past and present value of the table to the United States coal industry, and makes mention of the newest addition to the family of suspended, multiple-deck, counter-rotating, gear-driven, coal washing tables, the CONCENCO ""88"" Deister table."

Jan 1, 1973

By A. E. Boone

"The paper presents critical areas in which improved coordination of effort by industry, government and sup-pliers will be essential to continue the growth record of the Canadian mining industry into the 'seventies'. The analysis includes: exploration, production, mining methods, research and development, markets, management and industrial relations. Performance objectives are suggested where tangible results can be measured. The author suggests the methods by which the 'seventies' can be the greatest decade in the history of Canadian mining. It is indicated that a national mineral policy is essential to the Canadian mineral industry."

Jan 1, 1970

By A. P. Page, G. E. Alexander, L. L. Sirois, A. A. Winer

A knowledge of the electrical surface characteristics of minerals is all-important in the choice of treatments to up-grade and beneficiate them. At their solid-liquid contacts, there are transfers of ionic species, which for insoluble oxide minerals are the H+ and OH-ions. The adsorption density of these ions can be detected by carrying out potentiometric titrations, and this paper describes the automation of such an apparatus. The details are discussed fully and the validity of the method is demonstrated by flotation tests.

Jan 1, 1969

By John J. Laffin

"Nova Scotia Department of Mines and Energy Throughout the history of Nova Scotia, trends in the production and use of its coal resources have resulted in major impacts on the economy and society of the province. Current trends in coal demand locally, nationally and internationally are having and will have an increasing positive effect on Nova Scotia over the next twenty years-in terms of energy supply, job creation and general economic development. Coal for electrical generation is an immediate and key objective of Nova Scotia's energy plan; and, in the long term, coal-derived fuels will meet the province's needs for transportation fuels. Demand for metallurgical coal is also expected to increase, especially if the merchant coke plant currently under investigation becomes a reality.Meeting these coal supply and utilization objectives in the face of increasing environmental, social and economic constraints poses a tremendous technical challenge. Work has begun on projects to expand coal production capacity and to adapt new technologies for coal preparation and utilization to the specific needs of Nova Scotia; much more work will be required in the coming decade in order to succesfully tap this resource.IntroductionThe energy problem facing Atlantic Canada has a few unique features not found in the rest of the country. Canada, as a whole, has access to a diverse mix of energy resources, including crude oil, natural gas, coal, hydro and uranium, with the result that crude oil supplies only about 40 per cent of Canada's primary demand. In contrast, foreign crude oil dominates Atlantic Canada's energy mix, supplying over 70 per cent of the primary energy demand.This results in important differences in various sectors. Nationally, about 5 per cent of the electricity is generated from oil whereas last year in Nova Scotia approximately 40 per cent of the electricity generated was from imported oil. Residential, commercial and industrial space heating, and industrial process heating in Atlantic Canada was almost 100 percent dependent on foreign oil. This is in sharp contrast to the situation in central and western Canada, which have access to secure domestic natural gas, oil and hydro electricity."

Jan 1, 1982

By N. Musee, N. Kornelius

This study presents a neural network approach to modelling the liberation of gold bearing ores. A complete mineralogical analysis of unmilled and milled ores, including gold deportment and gangue content are used as inputs to a self-organising neural net which generates order preserving topological maps. The arrangement and shapes of these clusters are coupled to unmilled free gold data to predict gold liberation in milled ores (absolute error: 4.2%). Moreover, the self-organising maps were diagnostic of the quality of data used, indicating that the relationship between particle size and gangue material content requires further investigation.

Jan 1, 2005

By Sangjian Zhang, Zhu Xiao, Lairong Xiao, Rushi Chen, Mei Fang, Zhou Li

The copper-graphite metal matrix composites were fabricated by two different production methods: directly sintering with copper and graphite (Cu-Gr composite), and in-situ sintering with cuprous copper and graphite (Cu2O-Gr composite). During the in-situ reaction sintering, a redox reaction occurs at the interface of the Cu2O particles and Gr particles, resulting in the improved physical and mechanical properties of Cu2O-Gr composites. Compared with Cu-Gr composite, Cu2O-Gr composite has a higher compression strength at any given graphite content due to the improved interface bonding and uniformly distributed fine graphite particles in the matrix. Increasing graphite content decreases the mechanical properties of the copper-graphite composites. The compression strength of Cu2O-Gr composite is 50-100 MPa higher than that of Cu-Gr composite. INTRODUCTION Copper-graphite composites have been widely used in industry due to their low density, relatively high strength and hardness, good thermal and electrical conductivity, arc ablation resistance and self- lubrication ability (Grandin & Wiklund, 2018; Han & Xu, 1999; Huang et al., 2017). Electric sliding contact friction pair in the high-speed railway system and motor brush in electric contact components have a very high demand on electrical conductivity and self-lubrication ability of materials. The electric devices need to bear both mechanical load and high electric current. Copper-graphite composites with good mechanical, electric and self-lubrication properties are the best candidates for application in multifunctional electric sliding contact frication components. The relative sliding speed of friction pair is developing towards 100 m/s or even faster, which can withstand the electric flow of more than 800 A, and it is often accompanied with vibration and impact (Guo & Ding, 2008). Conventional wear-resistant materials can no longer meet the current requirements and this promotes the development of copper- graphite composites with excellent comprehensive properties (Ding, Chen, Zhu, Zhang, & Zhou, 2009; Yasar, Canakci, & Arslan, 2007). There are many ways to fabricate copper-graphite composites, mainly including powder metallurgy method, liquid immersion infiltration method, rapid sintering method and electrodeposition method (Kalin & Poljanec, 2018; Kim, Lee, & Han, 2014; Liu et al., 2018; Wang et al., 2018). Each method has its own advantages and disadvantages, and the powder metallurgy method is the most commonly used one due to its simple process, high economic benefit, and industrial production applicability. The common steps of the powder metallurgy method are as follows (Samal, Parihar, & Chaira, 2013): firstly mixing the copper (copper alloy) powders and graphite with a certain ratio, following by die-forming, and then sintering at the high temperature with or without pressure. The advantage of copper-graphite composites is that the graphite distributed in the copper matrix uniformly and it can form a carbon diaphragm preventing the wear of the composite (Fu & He, 2010). However, the bonding strength of the interface between the copper matrix and the graphite is relative low as the combination between them is mechanical interlocking but not metallurgical bonding (Ma et al., 2008). It is meaningful to develop new fabrication technology of copper-graphite composites with better interface bonding, which could provide guidance for the design of copper-graphite composites with excellent comprehensive properties.

Jan 1, 2019

By Syamujulu. M

Subsequent to the unbundling of the Zambia Consolidated Copper Mines (ZCCM) and the privatization of its constituent parts, the Konkola Copper Mines (KCM) represents a third of the original conglomerate. Now run by private hands as a sub group of Vedanta Resources Plc of India, KCM is strategizing on how best to deal with the operational issues of the organisation to resolve some of the difficult, logistical, environmental, mineralogical and metallurgical problems being encountered to tum them into opportunities as the company turns around. This paper reviews the options being put in place to provide appropriate solutions and strategies including the treatment of the highly siliceous low energy copper belt concentrates in its mining operations in Zambia.

Jan 1, 2007

By Robert B. Parsons

"For the fourth time in five years, residents of northern Canada have seen a change in the tax treatment of housing and travel costs. The latest changes announced in December 1990 by the Minister of Finance are to become effective in 1991. When will the tinkering stop?IntroductionFor man y years prior to 1987, certain travel and housing allowances received by employees in remote areas were generally considered by Revenue Canada to be tax-free, even though some observers suspected that such generous treatment was contrary to the provisions of the tax legislation. In the mid-eighties, Revenue Canada decided to reconsider the tax treatment of the mining industry's long standing practice of providing housing and travel assistance to these employees. The tax- free treatment was continued by virtue of annual remission orders, but only pending the enactment of legislation which would tackle the issue head-on and layout the rules in black and white to be seen by all. The sequence of events since then may be chronicled as follows:February 26, 1986-Finance Minister Wilson's budget present s the framework for the future tax treatment of travel and housing benefits provided to residents in remote regions of Canada.December 22, 1986-The Minister of Finance announces detailed rules to fill in the earlier announced framework.January 1, 1987-The new tax rules come into effect.April 29, 1988-The Minister of Finance announces the establishment of a Task Force to examine the existing criteria for determining the eligibility of residents of northern and isolated areas for tax benefits.October 27, 1989-The Task Force presents its report.December 7, 1990-Finance Minister Wilson announces a new system of tax benefits for residents of Canada's northern and isolatedregions.January 1, 1991-The new rules become effective."

Jan 1, 1991

"The Society for Mining, Metallurgy, and Exploration (SME) Inc. developed a guide of minimum standards for reporting exploration results, mineral resources, and mineral reserves for the purpose of informing the general public. The SME Guide has been adopted by the Society.History1. In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME), Inc., the President of SME formed Working Party #79, Ore Reserve Definition, with the mission to develop guidelines for the public reporting of exploration results, resources, and reserves. A Subcommittee was appointed by the Working Party to draft these guidelines and submit recommendations to SME. The Subcommittee's recommendations were published by SME in the April 1991 issue of ""Mining Engineering"", and as a document entitled ""A Guide for Reporting Exploration Information, Resources, and Reserves"" (the SME Guide) in January 1992. Work continued on an ad-hoc basis until 1996, when Working Party #79 was renamed the SME Resources and Reserves Committee and became a standing committee.In 1994, the Council of Mining and Metallurgical Institutions (CMMI) started a concerted international effort to create a set of international definitions for reporting mineral resources and mineral reserves. An ad-hoc International Definitions Group was formed, with representatives from mining and metallurgical institutions from the United States (SME), Australia (AusIMM), Canada (CIM), the United Kingdom (IMM) and South Africa (SAIMM). A major breakthrough came on October 18, 1997 when the CMMI International Definitions Group met in Denver, Colorado and reached a provisional agreement (the Denver Accord) on definitions of mineral resources and mineral reserves. Concurrently, and since 1992, the United Nations Economic Commission for Europe (UN-ECE) was developing an international framework classification for mineral resources and mineral reserves. Starting in October 1998, joint meetings were held in Geneva between the CMMI International Definitions Group and the UN-ECE Task Force, resulting in agreement to incorporate the CMMI definitions into the UN framework classification."

Jan 1, 2003

By M. Desjardins

The Hoyle Pond underground mine, located in the Porcupine Gold Camp, east of the city of Timmins, Ontario, Canada, is the cornerstone of Goldcorp Canada Ltd?s Porcupine Gold Mines. Cut and fill, shrinkage, longhole and panel mining methods are employed to excavate the narrow gold bearing structures. In order to meet increased flow requirements of 256 m3/s at the mine, a new Fresh Air Raise (FAR) and new surface fans were commissioned in early 2005. The newly acquired fans were capable of supplying the desired volume of air within a range of 1.5 and 2.0 kPa. Upon commissioning of the surface fans the total pressure was found to be exceedingly high; far beyond the design capabilities of the new installation. Consequently only one surface fan could be operated at any given time providing about half the required volume of air. Extensive work was immediately started aimed at reducing the system resistance in order to permit operation of the two fans in parallel and achieve the required mine flows. Larger booster fans were installed in parallel at the 900 m level, a 3 m raise bore linking the 450 and 900 m levels was developed to twin the existing fresh air circuit, and the FAR from surface to the 450 m level was twinned with the original FAR. This strategy, completed in 2012, resulted in a drastic reduction in system resistance and pressures, allowing the two surface fresh air fans to be safely operated in parallel and meeting the flow requirements. This paper describes details of the engineering design work and commissioning of the modified ventilation system, successfully ensuring the long term viability of the project.

Aug 1, 2013

By E. Burdukova

Rheological measurements have found a wide array of applications in mineral processing research. Rheological properties of mineral suspensions are highly dependent on the mineral surface properties as described by DLVO theory, and the relationship between these properties and inter-particle interactions is well established. In this paper, rheological properties of mineral suspensions are used to study the differences in behaviour of isotropic talc and anisotropic zirconia minerals as a function of varying properties of the suspension medium, such as pH and polymer dosage, specifically carboxymethyl cellulose (CMC). It was found that the rheological tests when carried out in parallel with electrophoretic or point of zero charge measurements, clearly reveal differences between behaviour of the suspensions of isotropic and anisotropic minerals. These differences are further accentuated with the addition of carboxymethyl cellulose (CMC).

Jan 1, 2006

By M. W. Bates, A. L. Mular

This paper, based on work carried out at Queen's University, describes the development and use of mathematical models of the parallel cyclone classifiers being used in the Strathcona mill of Falconbridge Nickel Min.es Ltd.

Jan 1, 1971