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By P. Abachi

Cemented carbides or hard metals that generally consist of hard tungsten carbide and a tough metal binder such as cobalt are important in many segments of the world economy, ranging from automobile related components to machining, cutting, and drilling tools. For metal cutting operations such as turning and milling, replaceable cemented carbide inserts are frequently used. The exposure of inserts to very severe conditions (e.g. temperatures as high as 1000°C) in combination with very high loads, limits their lifetime. When the tools and components are scrapped, they are collected with a view to recovering the tungsten carbide and cobalt due to both their environmental aspects and their strategic importance. In this work, a selective electrolysis process was used for recovery of WC powder particles from cemented carbide scraps. The WC-10Co and WC-10Co-VC up to 3 wt.% VC was produced using powder metallurgy route. The mean particle size of WC, Co and VC were selected as 2.5, l.5 and 2.2 µm respectively. Referring to electrochemical curves of WC-10Co cemented carbides in hydrochloric acid solutions with different concentrations, the recovery rate was enhanced in IN acid. Therefore, this solution was selected for recycling of all samples. The surfaces of as-produced and corroded specimens were investigated using a scanning electron microscopy (SEM). Detection of corrosion products was provided by energy dispersive spectrometry (EDS). According to results, the selective electrolysis process could be useful in the recycling of scrap carbide materials, although more studies should be undertaken on economical aspects of the process and the quality of samples produced using recovered powders.

Jan 1, 2005

By T. T. Tigert

INTRODUCTION THE PURPOSE of this article on methane is to present the simple basic facts of the characteristics, detection, occurrence, and control of this natural gas in metal mines, so that operators and .safety men may deal with it with some degree of confidence. Fortunately, although methane has been noted at many metal mines throughout Canada, the occurrences usually are small flows of short duration, and the ignitions experienced have, in most cases, had minor consequences. However, methane does present a hazard that can be of serious proportions, and ?any complacent attitude toward this gas that might exist in the minds .of people engaged in underground mining operations should be dispelled when it is ,pointed out that, in Ontario alone, ignitions of this gas have resulted in at least four fatalities, and eight men seriously injured and burned, during the past three years. lt is well-known that liberation of methane can and does .occur suddenly, often in mines where no gas has been found before, and that many ignitions and explosions have occurred in so called non-gassy mines. In view of this, it is apparent that no mine can, with any degree of certainty, be classified as non-gassy. CHARACTERISTICS OF METHANIZ The characteristics of natural gas encountered in most of the Ontario mines indicate that methane is the chief constituent. Methane (CH4), commonly termed 'marsh gas', and by the coal miner 'firedamp', is a colourless, odourless, and non-poisonous gas considerably lighter than air, and is the explosive gas frequently found in coal mines. Its physiological effects, closely resemble those resulting from nitrogen.

Jan 1, 1951

By Lisa L. Van Loon, Neil R. Banerjee

Canada is a world leader in uranium exploration, but many deposits are located in remote regions making exploration targeting challenging. Novel approaches are needed to detect the presence of large-scale ore-forming systems and to vector toward mineralization. Boron is commonly used as a key pathfinder element associated with sandstone/unconformity-hosted and basement-hosted uranium deposits in the Athabasca Basin, but the genetic relationship remains uncertain. Alteration assemblages containing boron geochemical anomalies are commonly spatially-associated with – and possibly coeval with – uranium mineralization. Boron is commonly found in tourmaline minerals but in some portions of ore deposits the host mineral for the anomalous boron remains cryptic. Boron coordination chemistry within alteration haloes can better constrain boron host mineralogy, provide insight into the nature of the boron-uranium relationship, and thus has the potential to better constrain targets for exploration. Synchrotron-source X-ray absorption near-edge structure (XANES) spectroscopy is a direct, element-specific analysis that identifies boron coordinated in both trigonally- (BO3) and tetrahedrally-coordinated (BO4) forms. This makes XANES uniquely suited for identifying the geochemical hosts for boron that may be related to hydrothermal ore forming processes. XANES spectroscopy was conducted on whole-rock assay powders from uranium deposits across the Athabasca basin containing boron concentrations ranging from <10 ppm to >10,000 ppm. XANES directly identifies the relative amount of trigonally- (BO3) and tetrahedrally-coordinated (BO4) boron in these complex mineralogical mixtures. Our work suggests a link between boron and uranium that is likely related to the unique physiochemical characteristics of ore bearing fluids that may provide a unique vector to mineralization.

Jan 1, 2020

By S. Kapusniak

Specialist Machine Developments (SMD) is a design and manufacturing company involved in the design of Remotely Operated Vehicles (ROV?s), ploughs, trenchers and mining machines for use in submerged environments. Established in 1971, the company has made over 500 vehicles for subsea use. These range in size from small remotely operated swimming vehicles with a weight of less than a tonne to heavy duty seabed crawling machines with a weight of up to 310 tonnes (in air). Primarily, these machines have been designed for offshore vessel-based applications, but the machines are equally suited to other submerged mining applications onshore. Many onshore deposits can technically and theoretically be mined using currently available submerged mining ROV technology. Similar equipment to that in use subsea could easily be fast-tracked into use to extend the life of opencast mines facing severe hydrological problems. It could also easily be used to mine vertical ore-bodies where the stripping ratio has become uneconomical due to increasing depth. In some cases mining ROVs could even be suitable for use as the primary extraction method for a new mine. Exploration and extraction techniques used in oil and gas gradually developed and moved from land to offshore in the middle of the last century. Are we about to witness a similar shift with other minerals? This paper describes the design concepts of submerged mining equipment, targetted subsea mineral deposits, the suitability of submerged mining ROVs for onshore deposits, limits to their application and parallel research and development activities which will help to accelerate the use of such equipment in the emerging submerged mining sector.

Aug 1, 2013

By L. P. Chrismas

"IN 1975, Nova Scotia produced 1.8 million tons of coal with a FOB mine value of $47.6 million. Of this total, about 30 per cent or 600,000 tons was coking coal and the remainder was steam and industrial-grade coal. The Nova Scotia Power Corporation consumed 630,000 tons in three generating stations and 570,000 tons were sold to Sydney Steel for making coke for its steel operations. Exports, principally to Great Britain, comprised 370,000 tons in 1975 in addition to the 300,- 000 tons shipped to other provinces for use by cement and pulp and paper companies. In 1975, just over 100,000 tons of coking coal were imported into the province from Alberta. Before 1975, low-volatile coking coal was traditionally obtained from the United States. In 1975, production came from seven individual mines and one project involving reclamation from mine dumps in Pictou County. Of the seven producers, four are owned by the Cape Breton Development Corporation, a federal Crown corporation; the remaining three are small independent mines, but, even though small, they are sizeable contributors to the economies of their local areas. After 101 years of continuous operation, Devco's Princess mine was closed in 1975. The Nova Scotia coal industry, in terms of value, accounted for about half of total mineral production in 1975. The industry provides jobs for 3,000 men and women. It is also significant that in 1975 Nova Scotia produced about 6.5 per cent of Canada's total coal production of 28.3 million tons. Detailed statistics on Nova Scotia's coal industry appear in the Appendix."

Jan 1, 1976

By Bradley Stoughton

It is very easy to reduce iron ore at a temperature well below its melting point and produce a more-or-less-pure metal which can be used directly for implements, tools, or machines. This simplicity has been the cause of much money loss by persons who were so satisfied with the successful operation of a process that they paid all too little attention to the commercial aspects of it. How easy a direct process is may be gleaned from the fact that it was practised with some -success by primitive man, and has been in almost continuous operation in one form or another for a period of probably 4,000 years. The production of steel in ton lots, beginning about 1860, brought a new phase into the economic situation, which, however, had been already greatly modified in 1784 by Henry Cort&apos;s invention of purifying pig iron. Direct processes survived both of these revolutions, under special geographical conditions, even up to the last few years of the nineteenth century, but ceased to have any general use as the basis of supply for structural, machine, or tool industries even in countries which could have manufactured iron by a direct process, but, instead, imported the product of established iron and steel processes. And this is still the situation today, notwithstanding the invention of an incredible number of &apos;new&apos; processes since 1900, most of which are abandoned, and only survived as along as their financial backers were willing and able to Jose money. Probably none of these processes failed to work pretty well, and all seemed to show a handsome profit on paper.

Jan 1, 1930

By M. A. Halim, V. I. Lakshmanan

Recycling is one of the key elements for sustainable process development for the recovery of value-added products and reducing environmental impact. Process Research ORTECH Inc. has developed several innovative and sustainable technologies, which minimizes the use of water, and chemicals for the recovery of gold, vanadium and gallium from secondary sources by maximizing the recycling of reagents, and reuse of water from process effluents.

Jan 1, 2015

By M. Ataka

Magnesium alloys are not easy to plastically deform at room temperature and may suffer from edge cracking at high reductions, especially during sheet rolling. In this study, the authors attempted to improve the rollability by the low-temperature hot rolling method, in which the rolling temperature range is lower than that of hot rolling, and also by the edge-heating method, which locally heats sheet edges.

Jan 1, 2006

By T. W. Wlodek, Zygmunt Kowalczyk

In the period from 1946 to 1964, the annual output of co al from Polish mines increased from 4 7.3 to 117.35 million tons. In this paper, the methods of bringing about this increase in productivity through the building of some twelve new collieries (producing some 15 million tons annually) and the modernization, reconstruction and extension of some thirty-six older collieries are discussed.

Jan 1, 1967

By G. P. Gormley

"Future open pit metallurgical coal mines in western Canada will be developed in complex geological environments. The success of these operations will be influenced by the mine operators&apos; ability to prepare accurate mine plans and to predict and, subsequently, 10 control both out-of-seam dilution and coal recovery. Quintette Coal Limited has been mining its tightly folded and severely faulted Mesa depo sit at annual rates of up to 9 Mt of raw coal, since October 1982. Ongoing development drilling combined with continuous utilization of blast hole information, has been required to achieve an acceptable geological data base for short range mine planning. Thrust faulting has been a primary geological cause of difficulty in selectively mining waste and coal, which has resulted in higher than expected dilution in plant feed. The same geological phenomenon has also increased reserves by 6.3% and allowed for expanded mine plans to include a lower thrust plate, ultimately doubling the mines original reserve base. This paper illustrates the geology of the Mesa deposit and the type of work involved in its interpretation. Regional GeologyThe Quintette Coal Limited (QCL) property is located in the Peace River Coal Field of northeastern British Columbia. In this area, northwesterly-trending folds of the Rocky Mountain foothills are commonly cut by multiple, low-angle thrust faults, which dip to the southwest. The Lower Cretaceous Gates Formation, of near shore continental origin, contains 5 to 7 mineable seams of medium volatile bituminous metallurgical coal (Figs. I and 2). These seams normally range in thickness between 0.75 m and 9.5 m and have an aggregate thickness of between 15 m and 22 m."

Jan 1, 1988

By Getu F. Biftu

There is general agreement among scientists that global surface temperatures have been increasing during the past decades. The increase in temperature is postulated to be the result of either an increase in greenhouse gases emission or climate variability (i.e., due to variations in sun or volcanic activity or El Nino and La Nina events) during past decades and may continue to increase. The effects of a predicted rise in the Earth?s surface temperature include an increase in average global evaporation and increase or decrease in precipitation (Bloomfield, 1992; Mann et al., 1991; Vinnikov et al., 1990; Gan 1995; Zhang et al., 2000a). The general circulation models (GCMs) project a global warming due to greenhouse effects of 1.5-4.5°C by the mid 2050s, with the most pronounced changes taking place in northern latitudes (Nicholls et al., 1996). However, similar predictions at a watershed scale or even a regional scale using GCMs are mot possible yet (Arnell et. al., 1996; Georgievskii et. al., 1996; Zhang et al., 2000a). Detection of historic trends, changes and variability in climatic variables is another indirect means of understanding potential future changes or variability at regional and local scales. The main objective of this paper is to review studies related to climatic change or variability and associated hydrologic changes at a regional scale and local scale, particularly those studies applicable to the Oil Sands Region (OSR) of Alberta. This paper identifies gaps in our current understanding of the hydrologic processes that may be affected by climate change; it discusses potential implications to developments in the OSR; and it explores mitigation opportunities including several that have already been implemented.

May 1, 2004

By T. Vovan, A. Galibois, M. Fiset

"In order to establish some links between the 22 specimens found on the site of Les Forges du St. Maurice, their slag inclusions have been analyzed by electron microprobe. Comparison between their contents of various specific oxides allowed us to segregate them into two major groups and even to isolate two sub-groups possibly characterized by some equilibrium between their oxides and/or the type of ores used.In all probability, limes/one coupled systematically with a soil rich in hydrated aluminum silicates was used as a flux.Based upon the existence of a pseudo equilibrium between the slag and the metal, the elaboration of the bulk of the specimens can be ascribed to the indirect rather than the direct method whereas the process temperature can be estimated at at least /400°C.RESUMEDans le but d&apos;etablir des liens entre les 22 objects provenant des Forges du St-Maurice, leurs inclusions de scories ont été analysées par microsonde. La comparison des teneurs en divers oxydes a permis de les séparer en deux groupes majeurs et même d&apos;y distinguer deux sous-groupes pouvant être reliés à la forme d&apos;équilibre entre certains oxydes et/ou au type de minerai utilisé. Selon toute vraisemblance, le fondant utilisé était de la pierre à chaux à laquelle on ajoutait systématiquement une terre riche en silicates hydratés d &apos;aluminium.Des considérations sur l&apos;existence d&apos;un certain équilibre entre les scories ei le métallaisset croire que la plupart des objets ont été élaborés plutôt par la méthode indirecte que directe et que la température d&apos;élaboration se situait à au maint 1400°C."

Jan 1, 1984

By T. A. Postolski, A. J. Sinclair

"Abstract - Where block (selective mining unit) grade distributions can be determined, the effect of average random errors of block grade estimates on metal recovery can be evaluated quantitatively. That is, for a given estimation error and cutoff grade, it is possible to calculate the quantity of metal that is lost as a result of misclassifying ore blocks as waste, as well as the dilution that ensues from misclassifying waste blocks as ore. Example calculations using a computer program GAINLOSS and realistic block grade distribution parameters for both a porphyry-type deposit and an epithermal gold deposit illustrate some fundamental relations that are important in quality control of estimation and in reconciliations concerning a comparison of ore estimates with production.Where the cutoff grade is on the lower tail of the grade distribution, metal arising from dilution can be much less than metal lost through misclassifying ore as waste. Hence, average grade of milled material could possibly be higher than expected (estimated) and tonnes milled will be smaller than estimated.Where the cutoff grade is on the higher tail of the grade distribution, tonnes arising from dilution will be greater than tonnes lost by misclassifying ore as waste. Thus, tonnage mined will be greater than estimated and the average grade milled will be less than estimated.The software GAINLOSS permits rapid comparison of the tonnes and average grade for all blocks selected as ore for a variety of levels of block estimation errors. These comparisons can be incorporated in a financial analysis to evaluate whether or not it is worthwhile to improve a high, average block estimation error to some lower value."

Jan 1, 1998

By S. A. Kenzap

This paper provides an overview and discussion of key aspects of operating risk valuation in underground metal mining systems, with impact on project economics, using stochastic computer modelling in Discounted Cash Flow (DCF) analysis. Mine operating risk classification and assessment for ground, equipment and scheduling aspects are presented with an overview of available risk valuation tools that have been developed in engineering disciplines. The classification is organized by keeping in perspective the mine design needs and constraints, as well as the potential economic impact that operating problems can have on an underground development and production system. These sources of cost, revenue and time delays are tabulated to enable the hierarchization of potentially hazardous unplanned events occurring during the mining project life cycle. In complex technological systems, like the underground mining systems, the decision-making process involve a wide range of uncertainties, and often this is based on subjective and qualitative expert evaluations. Whether a qualitative or quantitative analysis is conducted, it is often the case that the probability of a certain project parameter value needs to be estimated. This requires use of methods and techniques to handle subjective, qualitative measures and to combine them with quantitative stochastic modelling in order to evaluate mine operations-related issues on DCF economic performance measure parameters. Links are established between decision making and the risk-based mine planning process for evaluation of design alternatives, with emphasis on the need of introducing flexibility in mine design. Finally, challenges of risk-based mine planning and design implementations are discussed and the call for an integrated risk-based real options systems valuation (ROV) ?in? projects analysis is made.

Aug 1, 2013

By D. C. Reid

This paper describes the latest results in research and development currently being undertaken by the CSIRO Mining Technology Group to advance the automation capability of continuous mining equipment in underground coal mining operations. This research delivers enabling technologies that are essential in achieving increased roadway development rates as well as providing a safer working environment for underground mine personnel. Details are presented on technical developments and results of large-scale above-ground experiments conducted under field-realistic conditions. These experiments demonstrate the performance of the ?self-steering? capability which will enable a continuous miner (CM) to automatically maintain a given mining heading and mining horizon under production conditions. A primary technical requirement of this automated functionality is the means to accurately determine both the location and orientation of the CM in real-time. Test results of a high performance navigation system utilising vehicle motion aiding technologies are presented. This system combines high performance inertial sensors, and custom-developed radar to achieve a navigation-grade guidance system. Comprehensive performance evaluation has been conducted using a scale skid-steer mobility platform operating autonomously through a typical roadway development mining pattern with a total path length of 2700 m and mission duration of 112 min. Results from this evaluation demonstrate that the sustained accuracy of the navigation system exceeds the original project expectations and is well suited to the requirements for this underground mining application. There are presently no known alternative methods for providing a practical and accurate three-dimensional guidance solution in this application. This achievement represents a significant milestone in delivering a step change improvement in underground coal mining roadway development.

Aug 1, 2013

By J. Lebl, S. Bharti, D. J. Cornett

"This paper presents the design and application of blasthole mining to an area at Strathcona Mine previously employing post pillar cut-and-fill. Extensive mining in the area had led to gradually deteriorating ground conditions and post pillar stoping was no longer considered acceptable. Alternative methods had to be investigated.Conventional methods for mining in poor ground were rejected because of the high cost. Blasthole mining was selected because iI offered good productivity and safety with acceptable costs. The design of this approach involved field investigations and the use of numerical modelling to simulate the different blasthole options and their impact on ground stability. The blasthole design incorporated reinforcement with cablebolts, use of a radio-controlled remote LHD unit, large-diameter holes, blast design and wall control. Potentially unstable areas were outlined during mining with ground monitoring instruments and the results used to modify mining plans during the production phase.IntroductionIn underground metal mines there is a need to improve safety and productivity and lower mining costs in order to maintain reasonable rates of return on investment. This requires the application of good engineering design to both mine planning and ground control in order to optimize production and costs and to forecast potential problems during mining. The task becomes more important when extensive mining leads to gradually deteriorating ground conditions, making existing mining methods and techniques no longer acceptable from a safety point of view. Alternative mining methods must, however, be sufficiently productive to ensure profitability. This paper presents an example of the engineering design and operating approach used by Falconbridge in dealing with such a situation at Strathcona Mine."

Jan 1, 1983

By Rimas Pakalnis

This paper describes a focus of work presently being conducted at the Rock Mechanics Research Group at the University of British Columbia. The underhand method under consolidated fill ensures a high recovery under an engineered back that is comprised of cemented rock fill and/or cemented paste fill. This method of mining is generally necessary either due to a weak rock mass comprising the immediate back and/or high induced back stresses. A major concern in the design of sill mats is the loading and strengths associated with the overlying sill mat. This paper reviews past practice coupled with present observations and measurements from over ten(10) mines throughout North America. It outlines areas of concern in terms of design requirements.

Apr 1, 2005

By C. J. Mwenifumbo

Preservation of groundwater quality is a major environmental concern. The disposal of hazardous material from urban waste dumps, milling wastes in tailings ponds, and industrial wastes in injection wells may contaminate potential sources of potable groundwater. The containment or migration of contaminants in the subsurface depends on bedrock characteristics and type of overlying sediments. Fractured bedrock and permeable sediments that may provide pathways for the transport of potentially harmful contaminants should be avoided when selecting a disposal site. The role of borehole geophysics in hazardous waste-site investigations is reviewed in three categories: (I) site selection; (2) determination of the extent of contamination at existing sites; and (3) long-term monitoring of migration of contaminants. In the first category, borehole geophysical techniques developed for lithology and fracture identification, and for porosity determination, provide some of the necessary information for understanding the subsurface hydrogeology. Lithological information can be obtained from gamma-ray, electrical resistivity, induction, magnetic susceptibility, and sometimes induced polarization logs; fracture detection and characterization can be accomplished with the use of caliper, density, resistivity, temperature, and acoustic televiewer logs. Estimates of porosity are derived primarily from neutron-neutron, resistivity, density, and soniclogs. Borehole geophysical techniques used in water quality determinations include self-potential, fluid resistivity, Eh (redox potentials) and pH measurements, and these can be used to map the extent of contamination at an existing waste site. Cross borehole and borehole-to-surface electrical methods can also be used in this application. Long-term monitoring of contaminant migration in boreholes can be accomplished with techniques that respond to changes in electrical conductivity, temperature and fluid chemistry caused by the presence of contaminants.

Jan 1, 1993

By M. Mirnezami, D. Lascelles, J. A. Finch, E. El-Ammouri

"In a previous publication, the depressant action of Mg above pH 10 on Cu-activated sphalerite was described (Lascelles et al., 2001). In the present communication, a second role, aggregation is introduced.Aggregation (i.e., the tendency of particles to cluster) is measured using settling rate and turbidity converted to an aggregation index (AI) where 0 corresponds to dispersed and 1 to aggregated. Surveys of Cu and Zn flotation stages at four concentrators showed the A1 increased significantly above pH 9. The metal ions identified in the process waters, principally Ca and Mg, were tested to determine which might be responsible. The presence of Mg was found to be the most important, 50 ppm Mg having a greater impact than 500 ppm Ca fkom pH 9 to 1 1. In one plant, poor repeatability in A1 was suspected to be related to varying Mg levels; doping with Mg significantly increased AI.In both aggregation and depression, therefore, the common feature is the impact of Mg at pH > 9. Over this pH range Mg forms a range of hydroxy species, including Mg(OH)2 precipitates. Suggested aggregation and depression mechanisms associated with these precipitates are introduced. Possible problems and opportunities arising from the findings are discussed.INTRODUCTIONProcess waters in flotation circuits contain a variety of metal ions that may introduce unwanted activation or depression. Two common metal ions are calcium and magnesium. Typical concentrations are in the range 50 ppm Mg and 500 ppm Ca (Marticorena et al., 1994, Basilio et al., 1996, Negeri et al., 1997, Nesset et al., 1998)."

Jan 1, 2002

By K. Ananthanarayanan, R. I. L. Guthrie, S. A. Argyropoulos

"The low cost and availability of micro-computers and their peripherals provides the metallurgical engineer with the opportunity to use such computers in a wide variety of applications. In this paper, the authors describe the development of a low cost data acquisition system capable of measuring up to 8 analogue channels at a sampling rate of up to 5000 measure mentsper second. This system is equipped with proper hardware and software so that the micro-computer can be linked to a central computer facility such as the McGill System for Interactive Computing (MUSIC). This central computer facility is supported by an AMDAHL V7 computer. Using the present interface, communication rates between the microcomputer and the central computing facility can be as high as 9600 (baud).The above mentioned data acquisition system is currently used for monitoring dissolution kinetics of ferro-alloy additions in liquid steel. In addition to this, special software has been developed which enables the user of this system to monitor solidification rates of ingots, etc. As economic considerations are always important, comparisons have been made with existing recorders which show that the cost Of the present system is only 30 per cent more than a two-pen strip chart recorder.RESUMELa disponibilité et le bas prix des micro-ordinateurs et de leurs périphériques permet à l&apos;ingénieur métallurgiste d&apos;utiliser de tels ordinateurs pour diverses applications. Dans ce rapport, les auteurs décrivent le développement d&apos;un système d bas prix pour l&apos;acquisition des données, capable de mesurer jusqu&apos;à huit canaux analogues jusqu’à une vitesse de 5000 mesures par seconde. Ce système est équipe avec son propre ""hardware"" et ""Software"" qui relient le micro-ordinateur d’un ordinateur central, comme le système de McGill pour computations réciproques (MUSIC). Ce central d&apos;ordinateurs est soutenu par l&apos;ordinateur AMDAHL V7. Utilisant cet "" interface"", la vitesse de communication entre Ie micro-ordinateur et l&apos;ordinateur central peut atteindre jusqu&apos;d 9600 (baud)."

Jan 1, 1980