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By Sibabrata Patnayak

A major problem during shovel excavation in oil sand mining is the variability of material diggability resulting in varying mechanical energy input, cycle time, energy consumption, wear, and stress loading of shovel dipper-andtooth assembly. This variability greatly influences the mining equipment performance. Different approaches such as empirical ground classification systems, analytical methods, and performance monitoring that are used to determine diggability of groundmass are reviewed. It is concluded that the existing empirical diggability classification systems are site specific and mostly based on rock and therefore, cannot be used for shovel excavation in oil sands. The O&K wedge test is a simple and useful index test for establishing correlations between cutting resistance and geotechnical properties of coal and other soft rock overburden material. But this test, when performed on small size unconfined oil sand samples, may not give reliable indication of diggability because of the boundary conditions on the specimens. Digging predictions made using analytical and laboratory digging models need to be verified with performance monitoring data to better understand the digging effort in oil sands.

Apr 1, 2005

By T. Y. Chong, J. A. Folinsbee, M. Fullam

PJV Dome Mine has used some form of gravity concentration since start of milling operation in 1909 to recover free milling gold. Amalgamation and conventional jigs were first used and were replaced with the Knelson Concentrators in 1993. The Knelson concentrates produced were upgraded on a conventional shaking table prior to smelting and refining into gold bullion. In May 2002, a comprehensive review of the latest gravity recovery technology led to a piloting campaign aimed at further improving gravity recovery. The Knelson concentrates, subjected to intensive cyanide leaching in an Acacia pilot plant, were found to be amenable to intensive cyanide leaching with over 98% of the gold being dissolved within 24 hours. An Acacia Intensive Leach Reactor was successfully installed and commissioned in December 2002, to replace the shaking table. his paper describes pilot scale testing, installation, commissioning and optimization of the Acacia Intensive Leach Reactor. Also, the economic impacts on down stream processes are highlighted.

Jan 1, 2005

By M. J. Beus

Many mines in Canada, the United States and South Africa are reaching the hoisting limit. Very little payload will be possible without compromising safety due to the excessive weight. It has been suggested (DeLorme, 2000) that one of the most attractive concepts to enable deeper hoisting is to reduce the allowable factor of safety in the wire rope. Researchers at the Spokane Research Lab are developing new technology to improve hoisting safety and productivity by providing new monitoring and analytical tools. A Shaft Conveyance Monitoring System (SCMS) has been developed which determines hoist rope end load, true conveyance position and acceleration, and rope safety factor, as well as other hoist operating parameters. This information is transmitted to the hoist operator display 20 times per second. Recent field measurements on 45 mm (13/4 in.) diameter hoist rope indicate that dynamic forces during loading of a 9000 kg (10 ton) skip could exceed the safety factor of the rope. To improve on the current understanding of the mechanical behaviour of hoist ropes, and to help interpret the results from field-testing of the SCMS, a new approach to computer modelling of stranded wire rope is also being developed. Particle Flow Code, PFC3D (Itasca, 1999), is used to simulate the structural behaviour of wire rope and the interaction between individual strands when the rope is subjected to static and dynamic end loading. Details of the SCMS, field results from the measured rope loads, and the results of numerical modelling on the wire rope will be discussed.

Jan 1, 2002

By R. A. Bergman, C. A. Pickles, J. M. Toguri

"Black calcium cyanide is utilized mainly as a reagent for gold extraction. It is produced by reacting calcium cyanamide, sodium chloride and calcium carbide at temperatures in the range of 1200°C to 1400°C in a smothered arc furnace. The equivalent sodium cyanide content of the product is in the range of 45% to 50% and the calcium cyanamide conversion efficiency is in the range of 90% to 95%. Since black cyanide contains impurities such as salt and lime and also because the conversion efficiencies are below 100%, the product contains unwanted materials which significantly increase the shipping costs.The impurity content of the raw materials can not be lowered without increasing their cost and/or the processes to produce them, and therefore the present research was focussed on studying those factors which affect the cyanide grade. The major variables investigated were: the heating rate, the reaction temperature, the salt to cyanamide ratio, the nitrogen content of the calcium cyanamide, moisture additions and calcium carbide additions. It was found that each of these variables had a significant effect on the product grade. The highest cyanide content of the product was obtained for salt to cyanamide mass ratios of 0.55 to 0.60. The salt reduces the decomposition rate of the cyanide and, therefore, at low salt to cyanamide ratios and at higher temperatures, the product grade is decreased. It is likely that the salt evaporates at the higher reaction temperatures and this decreases the cyanide capacity of the melt. High heating rates minimize the residence time and thus salt evaporation is reduced and higher grades can be obtained. As expected, the cyanide content increased with the nitrogen content of the cyanamide. Calcium carbide additions resulted in an increase in the product grade. The presence of small amounts of moisture in the charge caused a significant decrease in the cyanide content of the black cyanide. An equilibrium reaction is postulated in order to explain the black cyanide process and in particular the effect of calcium carbide on the product grade."

Jan 1, 2002

By H. E. Pawson

"COMMON METHODS OF ELIMINATION: The four methods most frequently used to dispose of cyanide wastes are:1. Oxidation2. Dilution with water or with cyanide free wastes3. Acidification and dilution of resulting gas with air4. Alkaline ChlorinationMost operators practice a combination of the first two methods, allowing oxidation and dilution of cyanide waste in tailings ponds. Then, pond effluent is introduced to a stream for further dilution andoxidation which is expected to take care of the cyanide. This method oftreatment does work to a certain degree. Atmospheric oxidation in tailings ponds and in receiving streams chemically breaks down the cyanide radical to form carbon dioxide and nitrogen.2(CN) + 202 2 CO2 + N2The monetary advantage to this method is obvious to the operator but too frequently though, climatic conditions are ignored. Length of winter, and reduced flow of the receiving stream in summer, adversely restricts the result of this combined method. For those of us who rely mainly on dilution it would be wise to remember that 70 million pounds of water are required to dispose of one pound of sodium cyanide (1).The third method outlined involves addition of acid in a closed vessel and venting resulting gas to atmosphere with or without air dilution by mechanical means. Cost, safety and some form of secondary treatment to complete destruction of cyanide remaining in the solution usually make this method prohibitive.The alkaline chlorination method is the one most commonly accepted for treating cyanide bearing wastes since it is felt that cyanide is completely eliminated in this manner."

Jan 1, 1973

By D. Berkley

"The competitive pressure, the increasing energy costs and the environmental regulations impose substantial challenges to the definition of power plants serving industrial facilities. Primary mining and metallurgical facilities have even greater challenges because they are often located remotely, where the fuel supply can be a problem. The absence of a power grid imposes challenges on the reliability and quality of the electrical energy supply. In addition, the facilities usually require thermal energy too, not only electricity.This paper outlines these types of issues that have to be considered when defining a cogeneration plant integrated with a remotely located industrial facility. It is addressed to the “users” of cogeneration facilities rather than to “generators.” The focus is on analyzing various site-specific design considerations to prescreen the feasible cogeneration alternatives and minimize the number of options to be analyzed from the economics viewpoint. This approach could substantially reduce the engineering effort and schedule during the feasibility phase of the project.The front-end of the paper provides a basic understanding of cogeneration plants of various types to establish a common language. Subsequently, the paper outlines and analyzes specific issues that could be of help in the definition of cogeneration installations for remotely located industrial facilities, with a focus on mining and primary metallurgical plants"

Jan 1, 2003

By Knud Sinding

Environmental reporting by mining firms takes many forms and change frequently. The objective of these reports is related to increasing the legitimacy of mining firms with their diverse stakeholders. This study, focusing on internet-based reports, shows that there are considerable variations in reporting. This phenomenon is interesting because it belies the efforts pursued by leading industry members under iniatives such as the Global Mining Initiative and the Mining, Minerals and Sustainable Development project. The observed variation, both internally among reports and between reports and other industry policy statements, suggests that the industry needs to explore the possibilities for more convergence in terms of reporting quality. Based on theoretical constructs from the management literature we present a series of arguments defining necessary and sufficient conditions for durable and well-institutionalized reporting practices and standards.

May 1, 2002

What is the BC AMTA? ?What is an ASEP? ?Who are the partners? ?Critical Success Factors ?Questions/Answers Aboriginal Skills and Employment Program (ASEP) ?A collaborative partnership of industry, employers, post secondary, First Nations and government ?Working together to plan and implement training and education programs ?Demand-driven: targeted JOBS for participants

May 1, 2010

By Michael Harley, E. Guy Charlesworth

"Abstract - Bedding-parallel thrust-hosted gold veins are developed in the Sabie-Pilgrim's Rest goldfield, eastern Transvaal, South Africa. The reefs display a complex history characterized by temporally and spatially overlapping events of similar mineralization and deformation. Recognition of the episodic reactivation of these low angle (5° to 10°) thrust faults implicates high fluid pressures (equalling or exceeding lithostatic pressures). Geochemical constraints limit the amount of fluid-rock interaction and the occurrence of transgressive mineralization within the Archaean granitoid basement suggests that the high pressure fluids originated at depth beneath the Transvaal Basin.Similarities exist between gold deposits of Sabie-Pilgrim's Rest and Telfer, Western Australia as well as Passagem de Mariana, Minas Gerais, Brazil. All deposits are sub-parallel to the enclosing bedding which is shallowly inclined. Furthermore, they are also hosted by contractional deformational structures and are clearly epigenetic in origin."

Jan 1, 1994

By Alan D. Akerman

This paper describes the significant advantages and improvements in operational availability, reduced breakdowns, and overall cost reductions that can be achieved through the application of a Reliability Centred Maintenance (RCM) program, including Condition Based Maintenance (CBM) and Equipment Health Monitoring (EHM), in a mine environment. It uses a case study to illustrate the essential elements that constitute the basic requirements to establish such programs. This CBM case study analyzed the Load-Haul- Dump (LHD) vehicle sub-systems and their dominant failure modes, as a precursor to the development of condition indicators. The case study describes a disciplined process to enable condition indicator development and qualification in support of a CBM program. The identified condition indicators vary from readily applicable off-the-shelf monitoring systems and techniques, through to "leading edge" technologies that require further research and development. The paper also explores the developments that have been made in the combination of expert system software associated with modern computer based control systems, and the availability of "intelligent? sensor technology that complement the control system capability.

May 1, 2002

By L. K. Daneshmend

"Competitive pressures dictate that the mining industry moves to larger mobile underground haulage equipment with more advanced equipment mechanization, higher levels of autonomous operation of machines, and longer periods between access by maintenance personnel. Since such new machines will of necessity be more complex than existing designs, machine reliability has become a key issue in progressing toward advanced mobile underground haulage equipment. Reliability and maintainability models of such equipment are practically non-existent in the literature. This paper addresses the issue of reliability and maintainability of mobile underground haulage equipment on two fronts: reliability modelling to enhance decision making for maintenance planning; and reliability simulation to enable evaluation of more rigorous production planning scenarios. A case study from a gold mine in the Chilean Andes is presented, for which reliability models of mobile underground haulage equipment, specifically load-hauldump vehicles and underground haul trucks, are developed, and a reliability-based simulation implemented. IntroductionMaintenance accounts for 20% to 35% of the overall operating budget for a typical underground operation, and hence represents the largest portion of the mine’s controllable operating costs (Cutifani et al., 1996; Campbell, 1997; Goddard, 1998). This, coupled with the fact that industry today is faced with an ever more complex and demanding marketplace, has led to an increasing interest in methods to reduce maintenance costs.Although significant effort has gone into developing effective maintenance strategies for industry in general, application of these to the"

Jan 1, 2003

By M. Vallée

"Geological and technical problems are often considered the most important ones affecting new mining projects. Typical problems and likely causes are reviewed based on current Quality Management and Continuous Improvement (QMCI) perspectives, giving particular attention to the work of W.E. Deming. As the “system approach” is an essential part of these policies, its characteristics are described with particular attention given to cultural- behavioural, organizational and systembased constraints described by J. Gharajedaghi. Given that poor communication and interaction among geologists, mineral processors and mining engineers/operators can seriously affect the adequacy of tests, project planning and execution, and mine profitability, these interrelated processes within the mining systems are analyzed and modelled. The impacts on models and simulations of ignoring typical data, information and knowledge uncertainties are addressed. Adapting W.E. Deming’s Fourteen Points, System of Profound Knowledge and insistence on leadership, and the analysis of mining system constraints, will allow the effective QMCI approach required to reduce geological and technical risks. Whenever we achieve this goal, we will be in a better position to overcome environment-, market-, finance- and community-related problems, achieve higher company and industry profitability as well as more sustained development. RÉSUMÉLes problèmes géologiques et techniques sont souvent considérés les plus importants parmi ceux qui affectent les nouveaux projets miniers. Des problèmes typiques et leur causes sont étudiés dans la perspective de gestion de la qualité et d’amélioration continue (GQAC), en relation avec les travaux de W.E. Deming. Comme l’approche système est au centre de ces méthodes, ses caractéristiques sont décrites en donnant une attention particulière aux contraintes de types culturel-comportemental, organisationnel, et systémique décrites par J. Gharajedaghi. Compte-tenu que les lacunes dans les communications et les interactions entre géologues, minéralurgistes, et ingénieurs/opérateurs miniers peuvent affecter sérieusement la validité des essais, de la planification et de l’exécution des projets ainsi que la rentabilité des exploitations, ces processus connexes font l’objet d’analyse et de modélisation. Les impacts sur les modèles et les simulations de l’incertitude des données, informations et connaissances sont soulignés. En adaptant au système minier les Quatorze Obligations et le Système de connaissance approfondie de W.E. Deming ainsi que l’analyse des trois types de contraintes, nous pourrons développer une approche GQAC permettant de réduire les risques géologiques et techniques des projets miniers et des exploitations. Ceci nous pemettra de mieux faire face aux problèmes reliés à l’environnement, aux marchés, au financement et aux conditions sociales, d’améliorer la rentabilité des exploitations minières et de l’industrie, tout en contribuant de façon accrue au développement durable."

Jan 1, 2003

By Will Callupe Arzapalo

The success of the minimization of blast induced-damage at Barrick?s Pierina Mine in Peru is the result of an effective working relationship between Mine Operations and the Geotechnical Services Department. A detailed design criteria manual is used to match the blast plan to the site?s varying rock types and slope designs. The Geotechnical Services Department has further developed a comprehensive pre- and post-blast checklist that is critical to the drilling and blasting process as it pertains to wall stability. Wall control blasts are evaluated with quality assurance field checks, vibration monitoring and frequency control, video assisted performance quantification and post excavation face profiling. These detailed observations are compiled and summarized in a blast performance evaluation that is considered to be an ?Industry Best Practice?. The information and detail provided by each performance summary allows accurate blast analysis and effective design refinement.

May 1, 2006

By K. R. Coulter

"Good morning gentlemen. I am very pleased to have this opportunity to tell you a few of the things that happen within a completely unrelated activity, the electroplating industry, except that it does consume metals and has some slight similarity of problems so far as cyanide is concerned.First, just a few general terms about the industry. It is a relatively unsophisticated industry technically, and in many instances there are serious problems in obtaining staff that can operate the various systems that are currently available for destroying cyanide or precipitating metals.I would suggest to you that if you are investigating any system that you consider very seriously the personnel that are actually going to run it. The installation people; probably have some idea what it is all about but the operators must be chosen for their ability and not because they just happen to be available.We perhaps have another area in common. There is very little money for capital expenditures that produce no immediate return or even eventual return on the investment.The industry is largely made up of ""Jobbers"" who are strictly electroplating. There is another group in which the electroplating is captive as in large companions where it is a convenience operation. Also there are specialists, who do other things besides plating but it is a very major part of their operation. This applies to the automotive parts industry.Cyanide applications in the plating industry will be for copper, zinc, cadmium, silver, brass, and gold. Cyanide waste solutions come from those solutions adhering to the plated parts, and from the occasional discharge of the plating bath solutions. Also, in a related industry, the heat treating people with cyanide case hardening have some high concentrations of cyanide to dispose of. Concentrations of cyanide that we treat are 2500 parts per million or higher especially in wastes from heat treating. Solution volumes might be as low as 100 gallons per hour in a well run, carefully operated rinsing system. It may be as high as 3000 gallons per hour where dilution occurs."

Jan 1, 1973

By Michael G. Nelson

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modelling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing, allowing optimization of the mill processes on an almost realtime basis. This is not happening because mill feed it is often treated as a uniform material, when in reality it varies in composition and characteristics. The University of Utah is investigating the use of odor sensors for maintaining traceability in ore production and processing. Odor sensors now used in food processing, environmental monitoring, and other applications can detect the presence of very small amounts (0.1 - 500 ppm) of some molecules. An assortment of such molecules could be used to ?tag? blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ?electronic noses? could be used to assess its characteristics in real time.

May 1, 2004

"Placer Dome Inc.'s Dome Mine is located in South Porcupine, Ontario and has been in production since 1910. In the past, the mill leach circuit was preceded by preaeration and primary filtration circuits. These circuits were operated to overcome the effects of pyrrhotite in the ore which reacts with cyanide to form cyanates and thiocyanates and also consumes oxygen.In early 1989, primary filters were by-passed for an extended period. Actual plant results showed no affect on gold recovery or cyanide consumption so the circuit was left off-line permanently with significant cost savings.In 1990 it was determined that considerable savings could be realized underground if backfill storage facilities were located in the mill. It was decided to convert the preaeration pachucas to backfill storage tanks on a trial basis. The trial proved successful with no effect on recovery or significant increase in reagent consumption occurring due to the elimination of the preaeration circuit. The converted pachucas worked well as backfill storage tanks.Modifications such as these have helped to keep the Dome's millings costs among the lowest of Canadian gold producers."

Jan 1, 1992

By N. C. Clarke, T. Wu, M. le Page, K. J. Henley

In 1994, Gold Mines of Australia acquired the rights to the historic Mt. Lyell copper mine, and commenced a feasibility study into expanding production. The ore was shown in laboratory tests to be amenable to single-stage, fully autogenous grinding (FAG) of underground primary crushed ore, and this route offered the maximum cost savings. Flotation performance was expected to be enhanced. However, batch flotation tests done on pilot-scale autogenously ground ore showed an unexplainable recovery loss of between 1% and 3% Cu. A second pilot plant trial was set up, with the ground product feeding banks of continuous flotation cells. Single-stage FAG, FAG/pebble and FAG/ball circuits were tested. Results confirmed a loss of about 3% recovery with single-stage FAG milling. The FAG/ball circuit eliminated the loss. Analyses showed that autogenous milling probably produced more chalcopyrite/pyrite composites and that recovery of these composites was lower than with ball milling. In size fractions below about 53 microns, where chalcopyrite is well liberated, copper recovery was less affected by milling method and flotation selectivity. It was concluded that for the Mt. Lyell situation, a FAG/ball circuit was preferable to single-stage FAG.

Jan 1, 2002

By Aleksandar D. Bugarski

Despite extensive research efforts conducted in the past decades, occupational health risks associated with exposure to nano and ultrafine aerosols emitted by diesel power equipment are still not completely understood. The complexity of physical and chemical properties of diesel aerosols, constantly changing with the implementation of advanced diesel emissions control technologies, make this task rather challenging. The objective of this paper is to identify and characterize nanometer and ultrafine aerosols emitted by diesel engines in the underground environment and evaluate the effects of selected contemporary control technologies on physical properties, chemical composition, and in-vitro toxicology of diesel aerosols. The physical and chemical properties of the nanometer and ultrafine diesel aerosols are to be characterized through a test series in the NIOSH Lake Lynn Laboratory experimental mine. The crucial part of the study has been development of a facility that allows researchers to generate field results with precision and accuracy characteristics of a laboratory environment. The knowledge obtained from this study should strengthen our understanding of the health implications related to exposure to diesel particulate matter and aid in assessing the potential of various control technologies for reducing this exposure.

May 1, 2007

By Bruno Bussière

Le drainage minier acide (DMA) provenant de la circulation des eaux à travers les rejets miniers sulfureux est sans doute le principal problème environnemental auquel est confrontée l?industrie minière. Afin de prévenir les problèmes environnementaux reliés au DMA, on doit restreindre la présence de l?une et/ou de l?autre des principales composantes menant à la production d?acide, soit l?eau, l?air et les sulfures. Pour ce faire, différentes techniques ont été proposées au cours des dernières années, dont la désulfuration environnementale et les couvertures avec effets de barrière capillaire (CEBC). Dans ce papier, on propose d?utiliser ces deux techniques en combinaison. Ainsi, on produirait un rejet désulfuré à l?usine de traitement qui pourrait, par la suite, être utilisé comme matériau pour la couche de rétention d?eau de la CEBC. Dans un premier temps, on présente les résultats d?une étude de laboratoire qui montre qu?il est possible de désulfurer les rejets de concentrateur à l?aide de la flottation non sélective jusqu?à l?obtention d?un résidu non générateur d?acide. Par la suite, des essais en colonne ont permis de démontrer qu?il est possible de limiter la production de DMA d?un résidu sulfureux à l?aide d?une CEBC dont la couche fine est constituée de résidus désulfurés. Des prédictions théoriques estiment même que la présence de sulfures résiduels dans la fraction désulfurée utilisée comme matériau pour la rétention d?eau peut avoir un effet bénéfique en réduisant la migration d?oxygène. En effet, les sulfures contenus dans la couche de rétention d?eau peuvent consommer l?oxygène qui tente de migrer vers le bas et, ainsi, réduire les flux d?oxygène qui atteignent les rejets réactifs.

Nov 1, 2002

By Guy Chevalier

The QCM Mount-Wright mine and concentrator complex produces about 14 M tonnes of iron concentrate annually. Approximately 9.5 M tonnes of this concentrate are used to produce iron ore pellets at four different silica grades: Three for blast furnace operations and one for direct reduction furnaces. The paper presents the scientific approach that led to the realization of two projects where the acquisition of new process equipment led to an improved pellet plant iron recovery, a better flexibility and to lower operating costs as well as to the production of fine iron ore concentrate from the Port-Cartier tailings pond. Typical 4.8 % SiO2 concentrate is processed to achieve required pellet silica content. This is obtained with the aid of hindered settlers or hydraulic classifiers, screens, whims and, lately, spirals. The increasing demand for low silica iron ore products resulted in a greater need for upgrading. The Pellet Plant upgrading capacity being limited, more and more iron units were lost. Base on test works results and economic evaluations, QCM engineers figured out a way to increase efficiently their upgrading plant capacity and go back in the pond gather what has been lost in recent years of operation.

May 1, 2007