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By Matthew A. Baumann

Tooth-wear on mining shovels requires continuous monitoring. Worn teeth impede excavation performance, increase energy usage, and increase the risk of lost or broken teeth and adapters. A machine-vision-based automated tooth-wear monitoring system is presented. The system employs a rugged boom or stick-mounted camera to capture images of the shovel teeth. An onboard computer processes the images in real-time to determine the length of each tooth. The current wear state is available via a network-accessible log for on-demand status updates. By continuously recording tooth length changes over time, the logs can be used to estimate wear rates and patterns, permitting comparisons between different G.E.T. configurations, operator behaviour patterns, or material types. This detailed, quantitative data permits site-specific optimizations to wear packages and maintenance scheduling. Automating wear monitoring offers the crucial wear information necessary to minimize maintenance costs and reduce unscheduled downtime. A 37-day field trial in a copper-gold mine demonstrated the ability of the system to measure tooth lengths, compute wear rates, and detect differences in tooth wear based on their position on the bucket.

Nov 1, 2011

By Christopher W. Corti

A major aim of the GOLD 2003 conference, is to promote new gold related science and technology with a view to developing new useful industrial applications for gold. Current industrial uses have provided a steady annual industrial demand for gold of around 350-400 tonnes in recent years, the bulk of which is centred on electronics applications, with dental uses constituting the second largest application. However, there is good reason to believe that whilst gold will continue to play a major role in these sectors in the future, substantial growth of demand is not anticipated. Increased industrial demand for gold is only likely to come through the emergence of new applications, probably most significantly in five broad market sectors: ? Pollution and emission control technologies, including fuel cells. ? New uses for gold in advanced electronics, electrical systems and devices. ? Chemical processing of a range of bulk and speciality chemicals, using gold based catalysts ? Advanced coatings exploiting the novel properties of gold, particularly in nanoparticulate form. ? New biomedical uses for gold including medical treatments, drugs, implants, sensors and devices. There is cause for optimism that many new applications for gold could emerge in these sectors over the next decade and that this will lead to a substantial growth in demand for gold. It is clear that many of these new opportunities will be based on a chemical approach to synthesis of useful products rather than what has historically been a materials or mechanical approach. To turn this expectation into reality requires sustained support of R & D and a determination to exploit this new science and technology into viable commercial applications.

Oct 1, 2003

By Euler De Souza

"Underground operation ventilation energy requirements constitute a significant portion of mine energy consumption (40–50%) and total energy costs (25–40%). In general, mine ventilation systems are energy inefficient; the author has found several systems that operate at efficiencies below 65%. This paper presents how engineering design principles can improve the performance and efficiency of ventilation appliances, resulting in reduced power consumption and operating costs. Case studies demonstrate that, by retrofitting ventilation appliances using proper engineering concepts, systems will operate at efficiencies well above common operating efficiencies, resulting in a drastic reduction in costs and base electrical and energy loads.RÉSUMÉ Les besoins énergétiques nécessaires à l’aérage d’une exploitation souterraine représentent une part considérable de la consommation d’énergie d’une mine (de 40 à 50 %) ainsi que des coûts totaux liés à l’énergie (de 25 à 40 %). De manière générale, les systèmes d’aérage d’une mine sont loin d’être écoénergétiques ; l’auteur a trouvé plusieurs systèmes fonctionnant à des rendements inférieurs à 65 %. Cet article présente les principes de conception technique qui peuvent améliorer la performance et l’efficacité des systèmes d’aérage, entraînant une réduction de la consommation d’électricité et des coûts d’exploitation. Des études de cas montrent qu’en les rénovant à l’aide de concepts techniques adéquats, les systèmes d’aérage fonctionneront à des rendements bien supérieurs aux rendements habituels d’une exploitation. Ces rénovations donneront lieu à une réduction considérable des coûts ainsi que des charges électriques et énergétiques de base.INTRODUCTIONIncreasing electricity supply problems in North America have encouraged an industry-wide evaluation of energy consumption, resulting in a more urgent emphasis on energy-efficient design and operation for all energy-consuming systems. Electricity is the main mode of energy supply and the mining industry is affected by the increasing cost of this commodity (Natural Resources Canada, 2017). Ventilation systems normally operate 24 hours per day, 365 days per year, and account for 25–40% of the total energy costs and 40–50% of the electrical consumption of a mine operation (De Souza, 2013). Ventilation engineers are under ever-increasing pressure to reduce ventilation energy consumption and be cost effective."

Jan 1, 2018

By B. K. Ayres

Modern management of uranium mine or mill waste storage facilities (WSFs) often requires that they be remediated or decommissioned with a cover system. In addition to creating a self-sustaining landscape that supports the end land use, cover systems are intended to reduce long-term risks to human and ecological receptors from the stored waste to acceptable levels. The performance and longevity of a cover system will be strongly influenced by the features or shapes of the WSF final landform. Hence, cover systems and landforms must be thought of as an integrated design. Based on the author’s experience, the most important elements of the design process for maximizing the potential of WSF final landforms / cover systems being sustainable over the long term are noted in this manuscript. Several key items that must be considered and addressed during the planning phase of constructing a WSF final landform are also described. Various methods for monitoring performance of a WSF final landform are also reviewed. Key aspects associated with decommissioning a tailings WSF and waste rock pile at the former Cluff Lake uranium mine in northern Saskatchewan are included to illustrate many of the practical insights provided in this paper.

Jan 1, 2020

By Fred W. Brackebusch

"The use of paste technology for surface tailings disposal may offer economic, technical, safety, and environmental advantages for both underground and surface mining operations. Paste is a non-Newtonian fluid having some shear strength during transport and placement. The strength is augmented after placement by consolidation, water loss, and by addition of chemicals. Economical dewatering systems are necessary to the success of surface paste tailings disposal. In an underground mine, the paste backfill plant can produce paste for surface disposal about 50% of the time because only about 1/2 of the tailings are needed for backfill. The distribution of paste to the surface stack involves expensive pumping equipment and thus a nearby location of the stack is desirable. The viscosity of paste can often be manipulated by modifying pH. Placement of the paste in a designed stack configuration depends on topographic and climatic factors as well as paste properties.INTRODUCTIONThe use of paste technology for mine backfill is becoming accepted for underground mines mainly because of ground control and economic reasons. Paste technology is just starting to be applied for tailings disposal with only a few hardrock metal mines worldwide using the technology; however, it has been used extensively for red mud disposal in the aluminum industry. The disposal of dry tailings is very attractive from environmental and safety points of view because of limited water which might potentially escape and pollute river systems. Dry stacking systems, however, are expensive because of filtration and truck transportation costs. Paste can be produced from most tailings streams by special types of thickeners. Furthermore, it can be transported in pipelines, therefore paste technology may be more economic than dry stacking but still have some of the major advantages. Understanding of paste technology has improved through experience with operating underground backfill systems in recent years and because of testwork and research programs by mining companies, consultants and equipment vendors. Thus we may be on the verge of taking a new look at tailings management using paste technology."

Jan 1, 2002

By P. Wells, P. Quinn

"A moveable flotation miniplant was designed and constructed at the research laboratory of Inco Technical Services Ltd. to address the need for flowsheet development with a limited amount of ore (such as drill cores). It consists of one rod mill, two regrind ball mills, one vibratory screen, 24 flotation cells of various sizes and two Venturi aerated flotation columns. The setup has continuous monitoring capability for pH, dissolved oxygen, oxidation-reduction potential, conductivity and temperature in conditioning tanks and flotation cells. Various options regarding flotation reagents, circuit configurations, and fineness of primary grind and regrind can be readily evaluated. The throughput of the miniplant is 20 – 30 kg/hour ore.Unit operations such as flash flotation, magnetic separation and gravity concentration can also be evaluated as an integral part of an entire flowsheet development.This communication describes the basic design features of the miniplant and some examples of applications are given.INTRODUCTIONInco operates numerous mines in Sudbury and Thompson and will shortly bring the Voisey’s Bay mine into production. It has long been recognized that the ores from different mines or from different depths of the same mine can give different responses in flotation. There is a growing need to properly evaluate the ores before feeding the mill to maximize the return of the mine/mill operation. Inco Technical Services Limited at Sheridan Park, Mississauga, Ontario has developed a batch laboratory procedure to address this issue. The results are considered in the overall economical assessment of new mine operations.For ores that cannot be processed by the existing mill operations or that will be processed by a new mill, it is necessary to develop a flowsheet that can maximize the economical return of the mine/mill operation. While recognizing the importance and contribution of the laboratory batch flotation procedure, it does not generate reliable data for flowsheet simulation and design. A full-scale pilot plant campaign is normally required to obtain the design data but often this is not possible due to a limited amount of ore obtainable from the drill core. A small-scale pilot plant (mini pilot plant or miniplant) capable of processing 20-30 kg/h ore can provide this data prior to a full-scale pilot plant campaign. A miniplant can also be used to optimize the circuit configurations, reagent additions and recycle options of process water before pilot plant work and can be used to test a different flowsheet configuration for an existing mill before re-piping a plant circuit."

Jan 1, 2003

By B. R. Rakishev

When transferring from the railway transport to the combined automobile-conveyor transport by stripping works at coal mines, it was proposed to form at the working zone a concentration horizon for reloading part of the stripping volumes at the railway transport. The procedure is adduced for substantiating parameters of bloc-panels, depending on the step of transferring of reloading points in interrelation with the intensity of the working zone?s development with observing the balanced movement of parts of the stripping zone relative to the temporary concentration level.

Aug 1, 2013

By D. du Plessis, R. Stobbs

The Canadian Clean Power Coalition (CCPC) was created in 2001 to protect and enhance Canada’s vast coal and other carbon-based resource wealth, and to ensure that environmental public policy decisions recognize that these resources are a Canadian asset, not an environmental liability. To achieve its mandate, CCPC has undertaken to demonstrate technologies for use in new coal-fired power plants to control air emissions including carbon dioxide (CO2), nitrogen oxides (NOx), sulphur dioxides (SOx), mercury (Hg), and particulates (PM). The first phase of the demonstration project assessed three existing technologies for coal-fired power plants that reduce all emissions, including CO2, to levels equivalent to or below that of gas-fired power plants. The technologies considered in this phase included integrated gasification combined cycle (IGCC), ‘oxyfuel’ combustion, and amine scrubbing of pulverized coal. These technologies were evaluated with three coal types: Eastern bituminous, western sub-bituminous, and lignite coals. This paper presents the studies, conclusions concerning the capital and operating costs of these technologies, the cost of electricity produced (with CO2 removed), and the cost per tonne of CO2 avoided. It also discusses the potential for using captured CO2 for enhanced oil recovery, and possible technology enhancements for improving the competitiveness of gasification of low-rank western Canadian coals. The second ongoing phase of CCPC’s work includes the design and construction of a commercial-scale plant to demonstrate the feasibility of integrated gas combined cycle (IGCC) and/or polygeneration technologies and the potential for using the CO2 generated for enhanced recovery of conventional oil.

Jan 1, 2006

By Claude Dufresne

The technical development of the niobium-bearing products is to a great extent influenced by the striving of the respective industries to maintain or strengthen their positions in all fields of application against competing materials. South East Asia, China, Eastern Europe and CIS are slowly becoming significant consumers of ferroniobium. As a result, the world niobium market has been stable despite the slowdown in steel production in 2001. This paper will describe present producers, capacities and the current market conditions.

May 1, 2003

By C. A. Hardie, G. F. Leichtle, J. A. Finch, J. A. Watson

"The recycling of wastepaper has become an important and common process worldwide. Techniques similar to those used in the mineral processing industry are used to produce high quality recycled fibres for use in newsprint. The mineral processing group at McGill University, in conjunction with the Pulp and Paper industry (Mechanical and Chemi-mechanical Wood Pulp Network), has adapted one of these techniques, column flotation, for the purpose of deinking wastepaper. This article describes the typical process of recycling wastepaper from a mineral processing point of view. It also presents results from McGill University’s flotation column test work at a Québec wastepaper recycling facility. IntroductionThe recycling of wastepaper has become an important and common process worldwide, including Canada which is now the world’s largest importer of wastepaper (CPPA, 1996). Much of the current drive to increase the utilization rate of recovered paper is a reaction to the solid-waste disposal problem that faces many Canadian and United States municipalities. The real problem in the disposal of solid waste is not the absolute amount of garbage that must be disposed of each year, but this amount in relation to available disposal capacity.Environmental restrictions on the creation of new landfill sites and incinerators (the two main options for disposal of municipal solid waste) have tightened the demand/supply balance in the solid waste disposal market. This shrinking availability of waste disposal sites in the face of increasing population with greater disposal requirements defines the Developed World’s solid waste crisis. Not only are there fewer disposal sites available, but the costs of using them is skyrocketing. These factors have increased government regulations mandating recycled paper content in newsprint. Conservation and environmental issues make the current drive for wastepaper recycling a real issue and business opportunity."

Jan 1, 1999

By Derek J. Cyr

Climate has an immense impact on the properties of Athabasca oil sands and the ease or difficulty with which it is excavated and extracted. During the winter months, exposed oil sands surfaces freeze. When hydraulic and electric shovels used in the various operations in the Fort McMurray area excavate the benches, large frozen lumps are created. These lumps are either destined for a lump dump where increased costs are incurred due to rehandle, or they are sent to the primary crushers where they can cause significant downtimes by jamming the crusher. The crusher down time can sometimes be in the order of hours of lost production. Studies on data from two consecutive winters at Syncrude Canada?s North Mine show a high correlation between climate and the generation of frozen oil sands lumps. Temperature, ground cover, traffic, bench exposure time, oil sands grade and moisture content all contribute to this problem. A 1D frost penetration model was used to predict the depth of frost expected in oil sands and the corresponding likelihood of frozen oil sands lumps. To combat the challenge of frozen lump generation, a number of proactive and reactive measures can be taken: artificial snow, shallow ponds, scheduling, blasting or ripping.

May 1, 2004

By C. H. Dionne, J. A. Holmes, B. J. Huls

"Falconbridge Limited is presently developing flowsheet alternatives for implementation at the Strathcona Mill. The main thrust for change arises from the need to reject more pyrrhotite from the concentrate. To maintain appropriate levels of sulphur in the smelter concentrate, however, enhanced removal of non-sulphide gangue minerals must be realized. This could best be done in the Non-magnetics flotation circuit.Laboratory investigations were followed by an on-stream pilot test at Strathcona. The application of a column cleaner on the Non-magnetics concentrate resulted in significantly lower levels of fine gangue at equivalent sulphides recovery.This paper discusses the laboratory and pilot testing and results, with a focus on piloting. Also included is a discussion of the Strathcona Mill Flowsheet and the role of the Nonmagnetics flotation circuit.INTRODUCTIONFalconbridge Ltd. is currently developing means to reduce atmospheric sulphur dioxide emissions. One alternative is a reduction in the amount of pyrrhotite in Strathcona Mill concentrate, which reports to the smelter. Pyrrhotite in the Falconbridge ores contains an average of 39 percent sulphur and 0.64 percent nickel. By comparison, pentlandite contains an average of 33 percent sulphur and 34 percent nickel.A consequence of the rejection of pyrrhotite is a decrease in the sulphur assay in the remaining concentrate. This decrease causes downstream difficulties in the roasting process. Therefore, the content of non-sulphide gangue in the mill concentrate must also be reduced in order to maintain sulphur grades adequate for roasting. The resulting concentrate will have lower sulphur dioxide emissions while maintaining nickel production."

Jan 1, 1991

By M. Lindgren, M. Latva-Kokko

Process performance can be significantly influenced by proper design of hydrometallurgical reactors. Optimal reactor configuration is case specific and depends on process requirements such as reaction rate limiting factor and particle size distribution. Choice of materials and manufacturing methods also play important roles in highly corrosive and abrasive environment often involved in hydrometallurgical industry. In this paper performance of different reactor designs has been compared in some typical hydrometallurgical applications. Results show that significant improvement in energy consumption, gas utilization efficiency and equipment lifetime can be achieved with process specific reactor design.

Jan 1, 2014

By D. R. Murray

A four-year study was carried out to determine the ability of coniferous trees to aid in the reclamation of uranium tailings at Elliot Lake. Five species were planted: white cedar, white spruce, jack pine, scotch pine and red pine. More than 570 bare-root, two-year-old seedlings were planted on bare tailings and in areas of established grasses. A further division was made between areas of coarse and fine tailings. Over-all survival and growth of the trees has been far below expectations based on previous experience with several varieties of grasses. The criteria for assessment have been per cent survival and yearly growth as determined by plant height. Pine was superior, with 68% survival when planted in bare coarse tailings, 45% for vegetated coarse tailings and 34% for vegetated fine tailings. Cedar had the worst survival rates at 49%, 14% and 7% respectively. No species survived on bare fine tailings. The survival and growth of the coniferous trees have been related to species, environmental conditions and tailings properties.

Jan 1, 1978

By O. Mejia, J. Drozdiak

"This paper summarizes a comprehensive energy and cost study comparing an existing SAG mill based circuit at Huckleberry Mine with two proposed circuits involving comminution technologies which are associated with energy efficiency: high pressure grinding rolls (HPGR) and high speed stirred mills. The specific energy requirements expressed as kWh/t for the proposed circuits were determined from pilotscale HPGR and stirred mill testing conducted at the University of British Columbia. Samples and operating data were collected from Huckleberry’s copper-molybdenum concentrator to evaluate current mill performance for comparison. To support the base case, the SABC circuit was modeled using JK SimMet® software. The main comparison focused on the complete energy requirements for each circuit, including materials handling equipment such as conveyors, screens, feeders and pumps. This paper also provides capital and operating cost estimates for each of the comminution circuits. The results showed that the HPGR - ball mill circuit achieved a 21% reduction in energy consumption over the existing SAG - ball mill circuit at the same P80 grind size of 160 µm. At a grind of 80% passing 75 µm, the HPGR - stirred mill circuit showed a 34% reduction in energy compared to the base case. It was concluded that the energy reduction for the new flowsheets significantly improved the economics of the Huckleberry comminution duty.INTRODUCTIONUp until now, tumbling mills such as AG/SAG mills and ball mills have had a dominant bearing on the design and economics of comminution circuits. However, it is commonly agreed that the majority of employed comminution processes are energy intensive and energy inefficient, accounting for up to 80% of overall process plant energy consumption and having an efficiency of as low as 1% (Abouzeid and Fuerstenau, 2009; Fuerstenau and Abouzeid, 2002). The U.S. department of energy reported that there is a potential to reduce energy consumption in the metals industry by up to 61% from current practice to bestestimated practical minimum energy consumption; suggestions included the implementation of best practices and the adoption of energy efficient mining and mineral processing technologies such as advanced blasting techniques, high pressure grinding rolls (HPGR) and stirred mills (U.S. DOE, 2007)."

Jan 1, 2013

By D. Allan Coutts

Demonstration projects using hydrogen as a fuel are becoming very common. Often these projects rely on project-specific risk evaluations to support project safety decisions. This is necessary because regulations, codes, and standards (hereafter referred to as standards) are just being developed. This paper will review some of the approaches being used in these evolving standards, and techniques which demonstration projects can implement to bridge the gap between current requirements and stakeholder desires. Many of the evolving standards for hydrogen-fuel use performance-based language, which establishes minimum performance and safety objectives, as compared with prescriptive-based language that prescribes specific design solutions. This is being done for several reasons including: (1) concern that establishing specific design solutions too early will stifle invention, (2) sparse performance data necessary to support selection of design approaches, and (3) a risk-adverse public which is unwilling to accept losses that were incurred in developing previous prescriptive design standards. The evolving standards often contain words such as: ?The manufacturer shall implement the measures and provide the information necessary to minimize the risk of endangering a person?s safety or health.? This typically implies that the manufacturer or project manager must produce and document an acceptable level of risk. If accomplished using comprehensive and systematic process the demonstration project risk assessment can ease the transition to widespread commercialization. An approach to adequately evaluate and document the safety risk will be presented.

May 1, 2007

By Joseph J. Mgumbwa

Pillars are any structures left between two or more underground openings. The stability of pillars is normally considered to depend on shape (defined by width to height ratio), rock mass strength, extraction ratio, in situ stresses and the gross structural features (i.e. joints, contacts, faults etc). Recent experience has shown that pillar stability is also controlled by the relative orientation of the orebody with respect to the in situ principal stress. In inclined orebodies, pillars are loaded in compression and shear, thus creating unsymmetrical stress distribution. Failure mechanisms of these pillars are little known. This paper investigates the failure mechanisms of pillars under shear loading. Two dimensional elastic numerical modeling was used to examine the behavior of pillars in different orebody inclinations relative to the major farfield stress orientation. First, the paper reviews pillar design approaches including the empirical pillar design chart and uses numerical modeling to investigate the effect of the major farfield stress orientation on pillar stability. It is concluded that the empirical pillar design chart be used with caution, and that for orebodies under shear loading mine planning and design should take this into consideration since such geometrical orebody/stress relations put mine structures at higher risk of instability.

Oct 1, 2010

By D. J. Kemp

The 20th century saw changes in the mining and metallurgical industry not only technically but also in social and environmental expectations. As projects continue to become larger their visibility raises concerns among many groups. For mining companies, transparency, openness, and early engagement of all parties are fundamental to assure success. An equally important task is to anticipate the standards that will be required to meet society’s expectations in the 21st century.

Jan 1, 2005

By M A. Notte

Sand casting of steel is a process that offers the greatest design flexibility and highest metallurgical versatility. However, competition from other methods of fabrication is quite keen, constantly forcing the steel casting industry to the production of better quality castings at lower costs. New methods and materials have been put to use in the last ten years by foundries everywhere. This paper, in the form of a progress report, deals with new methods, processes and materials used by Canadian steel foundries for regular production, as well as with developments still in the initial but promising stages. T HE casting of steel to shape is the most direct method of producing steel parts in their final form. It is a basically economical process both as to cost and production time; it is also a process that offers design engineers the greatest flexibility and highest metallurgical versatility. In North America, the steel casting market has a normal yearly sales volume of 1,500,000 tons. In decreasing order, the largest customers are the railroads, construction machinery and earth-moving

Jan 1, 1965

By M. T. Ho, D. E. Wiley

The iron and steel industry accounts for almost 5 % of the total world CO2 emissions. Optimisation of the steelmaking process has led to significant reductions in the energy intensity to the point where it is now close to the thermodynamic limit. Further reductions are not likely to be achieved with efficiency improvement alone and will require the development of novel or breakthrough technologies. This paper will show the costs of implementing CO2 capture at direct atmospheric emission points for a number of iron and steel production processes. These include a conventional process, top gas recycling processes, the Corex and Hismelt smelt reduction processes and the Midrex direct reduction process. Depending on the point source emission, costs of capture with existing chemical absorption technology at iron and steel plants can be similar to capturing CO2 at pulverised coal fired power plants.

Jan 1, 2015