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By James E. Rider

"Fractures in mine hoist drumshafts are rare. We know of no previously reported attempts to repair a fractured drumshaft; any feasible method would involve welding and the associated problems of distortion, crack formation and strength.In June 1984, a fracture was discovered in the drumshaft of the production hoist in the Teck Corporation, Lamaque Division Mine at Val d'Or, Quebec. Delivery time on a new shaft would have been at least six months. The shaft was repaired in ten days and the total out -of-service time was four weeks.This paper describes why the shaft failed, how it was repaired, and the special alignment procedures employed during re-installation to minimize stresses in the repaired area.IntroductionThe performance of a mine hoist drumshaft is absolutely critical to mine operation. An inoperable drumshaft means no hoist, which in turn means no production or mine operation.Fractures in mine hoist drumshafts are rare. Previously when they have occurred, no one has seriously considered attempting a repair because of problems involved. Any feasible method would involve welding, which raises several major problems - namely, metallurgical, alignment, and strength.In July 1984 this very situation occurred at the Teck Corporation, Lamaque Division Mine in Val d'Or, Quebec.It was recognized that a new shaft would take at least 6 months' fabrication and delivery time. However, having had some experience at repairing broken shafts in other machines under similarly desperate circumstances, and after due consideration, it was concluded that by applying the correct techniques and engaging the right expertise, it would be possible to perform a repair and have the mine back in operation within a month.Thanks to outstanding efforts by all, the repair was accomplished in ten days and total out-of-service-time was only four weeks. The causes of the failure were determined and the calculated stress levels confirmed by strain gauge measurement during operation.The success of this project was achieved by adhering rigorously to fundamental management and engineering principles."

Jan 1, 1988

By James E. Rider

"Fractures in mine hoist drumshafts are rare. We know of no previously reported attempts to repair a fractured drumshaft; any feasible method would involve welding and the associated problems of distortion, crack formation and strength.In June 1984, a fracture was discovered in the drumshaft of the production hoist in the Teck Corporation, Lamaque Division Mine at Val d'Or, Quebec. Delivery time on a new shaft would have been at least six months. The shaft was repaired in ten days and the total out -of-service time was four weeks.This paper describes why the shaft failed, how it was repaired, and the special alignment procedures employed during re-installation to minimize stresses in the repaired area.IntroductionThe performance of a mine hoist drumshaft is absolutely critical to mine operation. An inoperable drumshaft means no hoist, which in turn means no production or mine operation.Fractures in mine hoist drumshafts are rare. Previously when they have occurred, no one has seriously considered attempting a repair because of problems involved. Any feasible method would involve welding, which raises several major problems - namely, metallurgical, alignment, and strength.In July 1984 this very situation occurred at the Teck Corporation, Lamaque Division Mine in Val d'Or, Quebec.It was recognized that a new shaft would take at least 6 months' fabrication and delivery time. However, having had some experience at repairing broken shafts in other machines under similarly desperate circumstances, and after due consideration, it was concluded that by applying the correct techniques and engaging the right expertise, it would be possible to perform a repair and have the mine back in operation within a month.Thanks to outstanding efforts by all, the repair was accomplished in ten days and total out-of-service-time was only four weeks. The causes of the failure were determined and the calculated stress levels confirmed by strain gauge measurement during operation.The success of this project was achieved by adhering rigorously to fundamental management and engineering principles."

Jan 1, 1988

By Mark Kennedy, Allan MacRae, Cameron Hams

New technology projects, particularly those involving first-of-a-kind metallurgical facilities, have a poor track record of achieving their overall financial targets, as they incorporate technological risks in addition to normal project risks. Traditional project management tools focus on risk from concept development through implementation, but typically fail to address the additional risks associated with a new technology project including slow start-up, slow ramp-up, and failure to achieve design performance (quality or throughput). These additional risks affect future cash flows produced by the project and hence its value, typically measured as net present value (NPV) or internal rate of return (IRR). Common accounting practice is to reduce the present value of future cash flows by applying a chosen discount rate, often reflecting the corporation's cost of capital. This discount rate does not contain an allowance for technological risk, which is often underestimated or misunderstood by both the financial and engineering project managers. This paper will focus on the topic of project risk and new technology, and how these play a role in the probability of achieving the predicted future cash flows. By properly addressing technological risk in the form of risk-weighted returns, marginal projects can be prevented from proceeding, while sound projects can be given the additional time and resources required to achieve the optimal level of front-end-loading (the level which returns the maximum risk-weighted net present value). A simple set of mathematical tools should enable engineers and financial professionals to establish a common level of understanding, thereby leading to a more accurate assessment whether a new technology project is ready to pass through its next level of approvals.

Jan 1, 2011

By L. I. Kiss, S. Perron, D. Toulouse, S. Poncsák, A. Perron

Bubbles play an important role in many industrial processes. In a Hall-Heroult cell, used for aluminum production, bubbles contribute to induce flow in the cell. The induced flow is important for the thermal balance of the cell as well as for the distribution and dissolution of the alumina. The existence of the bubble layer does not have advantages only. It increases the voltage of the cell and causes deformation along the cryolite-molten aluminum interface. The role of the anode inclination in the behaviour of the bubble layer as well as in the hydrodynamics of the bath is not clearly understood. In this work, the effect of the anode inclination angle on the bubble driven flow is studied in an industrial scale air-water model. The inclination angle is varied up to 5° from the horizontal. The instantaneous flow field is captured by Particle Image Velocimetry (PIV) system. The mean velocity fields were calculated by ensembleaveraging the instantaneous velocity fields measured at different time. The existence of the counter-flow in the interpolar space and the vortex in the side channel has been confirmed. Furthermore it has been observed that the effect of anode slope on the velocity field is weak.

Jan 1, 2006

By A. Montini, M. H. Moys

"A conductivity probe mounted in the shell of the mill has been used to measure the behaviour of the load in the mill as a function of operating variables. It was found that certain properties of the conductivity signal correlate strongly with the per cent solids of the slurry passing through the mill; in particular the angular location ?D of the shoulder of the load is an increasing function of the per cent solids. A method for measuring the viscosity of the pulp discharging from the mill has also been developed. The use of the measurements in mill control is illustrated by simulating various control strategies for open circuit milling. It is shown that the use of ?D allows very tight but imprecise control of the slurry rheology in the mill, while the use of viscosity is subject to severe limitations in speed of response. A cascade control system involving both measurements provides adequate control of slurry rheology within the mill. Applications to closed circuit milling are discussed.IntroductionMultivariable control of milling circuits continues to receive a lot of attention in the literature. Hulbert and co-workers and Niemi, et al. have described the use of Inverse Nyquist Array (INA) techniques while Herbst has recently described the use of Optimal Control. It is significant that in neither of these three projects was any variable associated with the grinding mill itself (e.g. power or properties of the mill discharge) used in the control strategy. Pauw, et al.do, however, use mill power in their multivariable peak-seeking controller for pebble-mill control. Little work has been published on the use of measurements of the properties of the slurry being discharged from grinding mills, in spite of the fact that milling efficiency is known to be strongly affected by slurry rheology».Moys has recently developed a technique for measuring the dynamic behaviour of the load in the grinding mill. This method involves the monitoring of the response of a conductivity probe mounted in the shell of the mill which gives a measurement of the orientation of the load inside the mill. It was found that the load behaviour was strongly influenced by slurry rheology. In this project a technique was also developed for the measurement of the viscosity of the slurry in the mill discharge. It was, thus, decided that it would be worth investigating the use of these measurements in mill control schemes since direct control of the slurry rheology in the mill must inevitably increase the efficiency and productivity of the grinding circuit as a whole.This will be done by using the dynamic responses measured by Moys and Montini to simulate the behaviour of an open circuit ball mill. While the control of open circuit mills is of little interest, this simulation provides a simple but powerful demonstration of the advantage provided by these measurements, advantages which should apply to closed circuit operation of any mill type (including autogenous milling). Investigations into multivariable control of a closed circuit ball mill are currently nearing completion and will be published soon."

Jan 1, 1987

By A. B. Parsons, P. G. Howes

"This article discusses how recent changes in the federal and Quebec .income tax laws have contributed to an improved investment climate for mineral exploration in the Province of Quebec. Individual investors who are resident in Quebec and who are in the highest tax bracket (1984-60.4% marginal rate) may obtain tax benefits that result in only nine cents of each invested dollar being at risk.IntroductionIn a recent submission by the Mining Association of Canada to the Royal Commission on the Economic Union, it was stated that the mining industry ""is no longer discovering and opening new mines at rates sufficient to offset the depletion of existing orebodies and to maintain pre sent output"". With world metal prices still in a depressed state following the prolonged 1981-82 recession, moreover, the continuing success of Canadian mining in world markets will depend on this country's ability to compete in a new environment characterized by subsidized Third World production . For the most part, this new competitive environment will encourage the development of cost-efficient mines that are better equipped to withstand the troughs and valleys of international metals prices."

Jan 1, 1984

By D. K. Storer, W. Lee, S. Tkach

"A microcomputer-controlled multi-probe K-40 monitoring system was developed internally for the Phase II mill at the Lanigan potash mine. The K-40 probes were mounted in a variety of positions in several process streams, ranging from dry ore on a conveyor belt to brines and slurries. A description will be presented of the objectives, the equipment and the difficulties encountered in correlating results.IntroductionThe successful control and optimization of most metallurgical processes involves monitoring not only physical parameters such as flow rate and temperature, but also the chemical compositions of critical streams. Composition has proven difficult to measure on -line in industrial scale processes. However, in potash processing there is a convenient chemical parameter that has long been utilized to measure in situ the concentration of potassium chloride (KCl). Potassium has a long-lived isotope which is slightly radioactive. K40 decays by beta elimination to Ca40, ultimately radiating a characteristic gamma-ray photon. This gamma emission when detected by scintillation counter can be used to estimate the concentration of potassium in a process stream."

Jan 1, 1990

By K. G. Wheeland, K. G. Byberg

The occurrence of a secondary, dust-fuelled explosion following blasting of sulphide ores has been reported in mines in many countries, including canada, the USA, Australia and South Africa. However there has been little effort to document the events and develop effective control technology. Following a detailed investigation of an incident at the Geco Di vision of Noranda Minerals Inc. , the company held a conference of interested parties in October 1986 to review the state-of-the-art and to agree on action. '!his paper outlines the causes and effects of such explosions, the key conference points and conclusions, and subsequent information-exchange and teclmology-developrnent activities.

May 11, 1988

By J. C. Taylor, J. A. Davis

"Existing environmental, health and safety regulations have forced pyrometallurgical facilities worldwide to drastically change some of their traditional methods of operation. In extreme cases, a number of facilities have been closed due to their inability to conform to these existing regulations. Tougher future legislation and government policy will lead to more stringent regulations and enforcement policies. The efficient control of smelter secondary emissions will, therefore, become critical to successful smelter operation.Much attention has been paid to the smelter primary process off-gas systems, including the development of new process designs to reduce the number of uncontrolled transfer operations. However, even the most modem smelter design requires control of its secondary contaminant sources, which mayor may not be directly related to the process operation.This paper discusses some of the potential secondary emissions encountered in many of the present process technologies. A few of the emission sources presented are only periodic in nature, such as those caused by maintenance procedures, but which have the capability of forcing smelter shut-down because of their direct impact on worker health and safety. The paper deals with a variety of topics relating to the efficient control, maintenance and monitoring of secondary emissions in copper, nickel, aluminum, magnesium and lead smelters, as well as in iron foundries and steel making facilities. Examples of the typical problems encountered in each of the above process operations are presented, including fume control at furnace tapping and slagging locations, metal transfer stations, tapping launders, and ladle transfer operations. The parameters for the most efficient design of fume capture systems, problems encountered with the handling and clean-up of certain collected emissions, and examples of successful solutions in particular operations are discussed."

Jan 1, 1994

By M. Phylli Bray

"Mining has the reputation of being a very ""macho"" industry. Recently, wider educational opportunities for women in nontraditional occupations and changes in mine technology have combined to make mining a viable career choice for women also. To benefit from this new resource, the mining industry faces the challenge of developing a different work environment from the one now burdened with sexism. Management supported initiatives are needed to facilitate such a transformation. The same rethinking of gender attitudes might also be extended to mining women in their traditional role as ""wife of"". The assumption that the male worker's wife is an unpaid adjunct is being questioned. It is suggested that women's separate concerns both as helpmate and as part of the mining workforce should be considered when planning for mining into the 21st century.IntroductionI must confess that, during the preparation of this paper, there have been many moments when I questioned my temerity. After all, I am not male, I am not an engineer, and I have never had a position in mine management. But as the wife of a mining engineer and a long-time resident of Northern Ontario mining towns, I do have an interest in the mining industry. This interest has had little to do with the technical and management aspects of the industry. Instead my research has been concerned with the impact the mining industry has on the people involved, particularly women, whether directly as employees or indirectly as wives. As I look toward the 21st century, I believe that the whole question of gender relations in the mining industry is one of the critical management issues smouldering below the surface."

Jan 1, 1995

By M. S. Moats

"The effects of commercial copper electrorefining additives (glue and thiourea) on the electrochemical removal of bismuth are of importance in copper production. It was found that Bi(III) electrodeposition occurs readily from acidic sulfate solution via a diffusion-controlled quasi-reversible reduction. The diffusion coefficient of Bi(III) was measured and found to be less than reported values of copper in similar solutions. The presence of thiourea and/or glue was found to accelerate or de-polarize Bi(III) reduction on stainless steel as compared to the inhibition or polarization of Cu(II) reduction. The additives also inhibited the dissolution of the Bi-Cu co-deposit during cyclic voltammetry. During short term deposition studies, the additives increased the concentration of Bi in co-deposited Cu-Bi products from solutions with low concentrations of Cu (<2 g/L). Bi deposition was significantly suppressed by increasing the Cu(II) concentration in the solution. The formation of a copper layer on the stainless steel electrode appeared to significantly suppress the reduction of Bi(III). This study demonstrates that glue and thiourea depolarize the deposition of bismuth on stainless steel. Therefore, the additives could be used to improve Bi impurity removal during third stage liberation.INTRODUCTIONThe production of high purity copper has been steadily increasing due to the wide application of the metal and its alloys in electrical and electronic products, infrastructure construction, industrial machinery and equipment, general products and transportation (Moskalyk et al., 2003). Most high purity copper is manufactured from copper sulfide mineral concentrates and/or scrap via a pyrometallurgical process followed by electrorefining (Navarro et al., 1999). During the electrorefining process, cast anodes of 99-99.5% purity are electrochemically dissolved into an acidified copper sulfate solution while high purity copper (>99.99%) is plated on stainless steel blanks or copper starter sheets (Davenport et al., 2002). The control of cathode deposit growth (purity and morphology) while maintaining a high current efficiency is of significant importance for copper refining (Ilkhchi et al., 2007). At typically applied current densities for industrial copper electrorefining, mass and charge transfer play important roles in the quality of cathodic products (Hiskey et al., 1998). If the real current density at some surface points is substantially higher owing to uneven current distribution, then rough spots can and will grow faster leading to nodules (Suarez et al., 1992). Nodulated deposits tend to capture solution and anode impurities (slimes) resulting in unacceptable cathode quality (Afifi et al., 1987). Furthermore, these nodules can grow until they eventually contact the anode leading to short circuits and current efficiency reduction (Ilkhchi et al. 2007)."

Jan 1, 2016

By K. Delbeke

Within the framework of the EU Existing Substance (93/793/EEC) and REACH regulations EC/1907/2006), the copper industry initiated in 2000 a comprehensive Voluntary Risk Assessment of copper and several copper compounds. The Italian Government&apos;s Istituto Superiore di Sanità, reviewed the process and reports on behalf of the European Commission. Copper exposure levels to man and the environment from production of copper anodes and cathodes, copper powders and copper chemicals as well as fabrication and use of semi-fabrication products and down stream user products were collected across Europe. Environmental and human health effects data were obtained from literature as well as novel research programs and used to deduct safe threshold

Jan 1, 2007

By M. J. Lopatka

This paper presents the results of field test and theoretical analysis driving resistance articulated 4x4 tracked robot test-bed. Tests were made on four different grounds. Designated elastomeric tracks resistance coefficients are much higher than for steel tracks. This information was important for the proper estimation of energy consumption in the process of driving.

Aug 1, 2013

By S. A. Kenzap

Risk & Uncertainty ? Uncertainty about a situation can often indicate risk, which is the possibility of loss, damage, or any other undesirable event. Most people desire low risk, which would translate to a high probability of success, profit, or some form of gain. Risk = Likelihood x Consequence Risk is the possibility of loss, damage, or any other undesirable event.

Oct 1, 2010

By Victor Rudenno

"Previous methods have employed statistical analysis to model future mineral resources. The method presented in this paper uses Zipj&apos;s Law to determine the size and grade of tin deposits still to be discovered. The law is applied independently to both known deposit tonnage and grades. A probability distribution for both &apos;tonnage and grade is computed/or those deposits still to be located and then, by applying a correlation between tonnage and grade, a distribution of the probability of metal content discovery is obtained.By considering an economic cut-off in metal contained in a deposit, the probability of economic success for the next tin discovery is computed, both for a world discovery and for the special case of Tasmania, Australia. The results indicate a probability of 11-37% on a world-wide basis and 18% chance of economic success in Tasmania.IntroductionIn the past , most attempts to determine the probability of success in finding an economic mineral deposit have relied on the accumulation of statistical data. These data are then used to predict a suitable frequency distribution to assess the probability of finding a deposit of a given size and grade (Singer,1975).The method not only relies on one having sufficient data, but also on the assumption that the data are not biased and that the distribution (usually log-normal) is a correct one. The method presented in this paper, to analyze tin deposits, uses Zipf&apos;s Law, which has been recently applied to oil, uranium, lead-zinc and gold deposits by Folinsbee (1977) and to Western Australian gold deposits by Rowlands and Sampey (1977). Tapp and Koniuszko (1978) have applied Zipf&apos;s Law to mineral distribution patterns in the Northern Australian orogenic provinces, which has enabled them to make predictions with a relatively small data source."

Jan 1, 1981

By Graham Sim

Agenda ?The Water Challenge ?Examples from Three Case Studies ?Mine Drainage, 99% recovery ?Mine Drainage, 80% recovery ?Road Dust Control ?Technology Development ? Conclusion Global water challenges Assuring sustainable quantity Improving water quality Reducing energy consumption

May 1, 2011

By G. Bonnivard

"A complete laboratory process for the treatment of lateritic ores containing a high proportion of iron, as well as chrome and alumina, has been established. The ores treated originate from the tropical zones and result from superficial climatic alteration. According to recent estimates, the known reserves of such ores reach many billions of tons, thus representing huge potential reserves for the elements they contain.The process used is based on the alkaline roasting of pelletized ore in the presence of sodium carbonate. This treatment results in the separate recovery of pellets of upgraded iron ore, pure chrome oxide and hydrated alumina. The research described in the paper aims at determining the best experimental conditions for obtaining the highest extraction of the required oxide from this type of ore."

Jan 1, 1967

By Robert B. Parsons

"The budget that was tabled by Finance Minister MacEachen on November 12, 1981 will result in a major tax reform of Canada&apos;s income and sales tax systems, the likes of which have not been witnessed by taxpayers since 1971. All segments of the economy will be affected one way or another by the far-reaching budget proposals; the mining industry did not escape untouched.Important changes will be introduced which will alter some of the fundamentals of structuring mineral resource ventures in Canada. This month, Tax Notes examines these changes, and also summarizes the other highlights of this key federal budget.IntroductionFinance Minister MacEachen&apos;s budget, with its lower personal tax rates, loophole plugging and tax shelter bashing, represents the biggest shakeup in our tax system since tax reform in 1971. In his budget, presented in the House of Commons on November 12, Mr. MacEachen proposed substantially lower tax rates for middle and upper income individuals, with the top federal and provincial tax rate dropping to about 50%, but in return he eliminated most of the opportunities for individuals, and corporations, to reduce or defer taxes through a wide variety of tax shelter and tax planning mechanisms.Although many of those budget proposals that dealt with the resource industries focused on the implementation of the September 1, 1981 agreement reached by the federal and Alberta governments concerning the National Energy Program (see Tax Notes in the December 1981 issue of the Bulletin), the budget also contained some proposed amendments that would have significant implications for investment in the mining industry.This month, Tax Notes examines these latter proposals, and also summarizes very briefly those budget proposals which are not unique to the resource sector."

Jan 1, 1982

By K. T. Aye

An investigation into the leaching of chalcocite and covellite in cyanide solutions at concentrations typically encountered daring gold cyanidation has been conducted. The results indicate that, for both minerals, the extent of leaching is greater under anoxic conditions, but is still incomplete even in the presence of free cyanide ions, with undissolved copper solids remaining in equilibrium with solution species. The speciation of the sulfur and cyanide reaction products in solution are interpreted in terms of the fast formation of a copper(I)- cyanide complexes in solution and a sulfur-rich copper(I) polysulfide solid phase, which then reacts more slowly to produce thiocyanate ions.

Jan 1, 2011

By W. G. Jeffery

"The mining and mineral industries have been, and remain, a major component of the Canadian economy. There are approximately 560 producing mining establishments of which there are some 130 metal mines and an equal number of non-metal mines, the balance being quarries for stone, sand and gravel. For 17 metals and minerals, Canada ranks within the top five as a world producer. There are 29 metallurgical plants. Employment in mining, smelting and refining was about 150000 in 1990. Mineral production, including coal, is about $20 billion. Exports up to the metal stage amount to $15 billion providing a positive trade balance of some $10 billion.The producing industry has a wide diversity of products. The companies range from small single mining operations to large multinationals. In terms of technology the industry has always been in the forefront of cost-effective practice, either using home-grown innovation or freely importing technology from around the world,The Mining Industry Technology Council (MITEC) makes an annual survey of the exploration and R&D expenditures of the senior mining industry that is the mining companies that are involved in mineral production from their existing mines. It does not include those companies solely involved in exploration using funds raised through equity sales.Table 1 shows the actual R&D and exploration expenditures as a per cent of sales. R&D shows a rising trend since 1988although the drop in value of output due to lower prices must be recognized as contributing to the increase. The point about this compilation is that the mining industry re-invests some 4070 of its sales in both exploration and R&D in order to sustain itself. Exploration for the renewal of metal inventories for future mining is a process unique to mining. It is not classified as R&D, and the necessity for this investment goes unrecognized by those who state that the industry does not do enough R&D."

Jan 1, 1993