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By Robert B. Parsons

"It is generally acknowledged that Canadian and foreign-based mining companies are spending relatively fewer dollars in Canada and more dollars abroad than was the case not many years ago. It is common to see the Canadian tax system being fingered as one of the causes in this shift in direction. However, if one takes the time to peel away the surface of our tax system, and to probe a little deeper into its substance, it will be found that the Canadian taxation of mining is generally quite competitive. IntroductionCross-border shopping in the mining industry? - Absolutely! Economics 100 teaches that dollars are votes in the capitalist system, and mining companies are going to cast their limited number of votes where they can achieve the highest return at the least risk. The Canadian consumer knows that taxes are a major factor in cross-border shopping, and mining company executives know that the same tenet holds true in their industry. Unfortunately, mining operations are subject to such a bewildering array of tax rules that making an intelligent decision is not always an easy matter.Statutory Tax RatesConsider, for example, the ""statutory"" tax rates shown in Table 1. (Statutory tax rate in this table refers to the simple sum of federal and provincial tax rates on profits as specified in the tax legislation.) Looking only at the total statutory tax rates (such as 66070 for Manitoba) , one might quickly observe that the Canadian mining industry is subject to a truly onerous tax regime, especially as compared to the United States where statutory tax rates can be in the 34% range."

Jan 1, 1992

By Lorne Roberts

"This paper describes: how Falconbridge's fire protection system meets the needs of the Lockerby Mine; why the system was chosen over other alternatives; how it is unique, but can be applied to any underground situation; details of the system; how it was installed; the role of a fire protection company; and general considerations when choosing afire-suppresant system.IntroductionIn May 1981, after about three years of searching for the best fire protection system for the re-opened Lockerby nickel mine at Whitefish, near Sudbury, Ontario, Falconbridge Nickel Mines Ltd. installed an AFFF type of fire suppression system. It was designed and supplied by the Fire Protection Systems Division of Levitt -Safety Ltd.The system protects against loss of life, equipment and/or production, and it complies with legislation should fire occur in a fuel storage area and/or scooptram garage and service bay at any or all of the three levels near Shaft No.2.About 18 months after Levitt-Safety began working with Falconbridge, the system was designed and installed at a cost considerably less than that which would be incurred if fire damage caused the loss of two days of production.The fire protection system, which overcomes a limited water supply, is a self-contained balanced pressure proportioning system. It senses the flow and automatically determines the correct concentration of foam to water. It is triggered by a release mechanism which operates a bank of nitrogen cylinders, which in turn pressurize a pressure vessel to expel the foam concentrate and water from the tanks. This solution is piped to sprinkler heads in the specific area."

Jan 1, 1982

By Garth A. Maki, Douglas M. Smith

"The largest Canadian Lamella thickener installation to date, with 13,600 square feet of effective clarification area, is being successfully operated at the Rocanville Division of the Potash Corporation of Saskatchewan. This paper describes the operational principles and design features of the Lamella thickener, the testwork leading to its specification f or the Rocanville phase two expansion project and a review of the performance of the full- size unit which was ultimately installed.IntroductionThickening equipment operating in the Saskatchewan potash industry is generally situated within the main refinery building or a separate insulated an d he a ted structure due to the harsh winter climate and the need to closely control plant brine temperatures to en sure good flotation circuit performance Because these thickeners process large volumes of slurries, conventional basin-type designs tend to be large, ranging up to 46 metres in diameter or more. As part of the general effort to minimize capital costs, the potash industry has begun investigating the use of alternate high capacity, compact thickener designs. In this regard, PCS Rocanville undertook a program in 1978 to evaluate a LamellaTM thickener and one other type of ‘High Rate' thickener as alternatives to a conventional design for the phase two expansion project.This paper describes the operational principles and design features o f the Lamella thickener (manufactured by Axel Johnson lnc.), the testwork leading to the specification of a Lamella for the Rocanville expansion project and are view of the performance of the full size unit (1486 m2 of the effective settling area) which was ultimately installed and is now successfully operating in the Rocanville plant."

Jan 1, 1983

By K. R. Wood, G. W. McDonald

"The tailings disposal system at Les Mines Selbaie includes dewatering of tailings in a high-capacity thickener, followed by point discharge of the thickened solids to form a stable conical pile. Tailings water drains to ponds formed behind engineered dams, prior to either recycling f or process use or discharge to the environment. Design and economic considerations of the system are discussed. Construction, start-up and operating experiences are also presented.Introduction Les Mines Selbaie is located in the Abitibi region of northwestern Quebec, approximately 700 km north of Toronto and 150km south of James Bay. More locally, the Detour gold mine is 60 km to the west while the Noranda smelter is 220 km to the south.The deposit was discovered as a result of a Questor INPUT Mark VI geophysical survey in 1973, followed by diamond drill programs from 1974 to 1976. Three mineralized zones were delineated and underground exploration was carried out on all three. A production decision for the 'B-zone' copper-gold-silver orebody was made in July 1979. The underground operation started in July 1981, with full production of 1500 t/d being achieved in May 1982.During the planning phase, every effort was made to ensure that the operation would be environmentally sound . The design included the provisions of the then newly proposed provincial environmental guidelines. The tailings disposal system formed the most significant part of the environmental program due to the large volumes of solids and water effluent. In addition, the design allowed for future expansion of the system to accommodate mining of the other zones, thus minimizing future costs and disruptions."

Jan 1, 1986

By Stephen G. Hardcastle, Michel G. Grenier

"Safety and health issues are and have been in the last decade a very high priority item with all parties involved in the Canadian mining industry. As a result of this high level of concern for workers' safety and health, Canadian mines are at the leading edge of environmental control technology. For the most part, the occurrence of pollutants in mines is unavoidable. Dust from mining operations, airborne radiation, gases and heat from the strata as well as gases and particulate from diesel engine emissions will undoubtedly be found to some level in most Canadian mines. A lot of work remains to be done, however, in order to bring all Canadian mines at the same level of proficiency when it comes to safety and health. Also, more work is needed in order to maintain our status as world leaders in this field.CANMET's Mining Research Laboratories (MRL) in Elliot Lake and Bells Corners, Ontario, with the cooperation of the mining industry, have contributed to improving environmental conditions in underground and surface mining and milling operations. The extent of collaboration and efforts vary widely from long-term, multi-million dollar projects between several interested parties to smaller projects involving one laboratory and a single mining operation. This paper gives examples of such collaborative efforts and potential future directions as they apply to: mine ventilation analysis using tracer gas techniques, optimization of mine ventilation network efficiency using real-time monitoring and controlled recirculation (heat saving), respirable dust and radiation sampling and control techniques, diesel emission control using regenerative ceramic filters and, finally, the control of sulphide dust explosions and resulting sulphur dioxide production."

Jan 1, 1990

By D. Virely, M. Gasc-Barbier, J. Guittard

"The valleys of the Dordogne and the Vézère (France) have been inhabited since prehistoric times, as evidenced by the famous site of Lascaux. A few miles away, the village of La Roque-Gageac is also a very popular tourist destination (about 1.5 million tourists per year): The village is sandwiched between a massive limestone cliff and the Dordogne river. The collapse of a cave roof high above the village in January 2010 led us to characterize instability together for the cave and the whole cliff and propose a adapted instrumentation to monitor the fracture openings in the rock mass that are linked to climatic variations. Measurements have been going on and been recorded for nearly 4 years. They point out the role of thermal stress fatigue in the breakdown of the rock mass. In this paper we describe the site under study, the instrumentation and its main results. INTRODUCTIONThe phenomenon of thermal fatigue has been very little studied as far as rocks are concerned, whereas it is rather well characterized for other types of materials: Elsevier published a journal dedicated to fatigue (International Journal of fatigue). In the case of rocks, thermal phenomena and their impacts on mechanical behavior have been analyzed from a micro-structural point of view, and it is now well-known that an increase in temperature causes a dilatation of crystals (Arnould et al., 2004; Berest & Weber, 1998). This dilatation may lead to the development of inter-granular traction and compression stresses, and if those stresses are greater than fracture strength, inter-granular and intra-granular cracks may take place. On the other hand, the fatigue phenomenon (cyclic repetition of a temperature variation which is less extreme than the one that may lead to this inter-granular or intra-granular fracture) is a phenomenon which has not been much studied.The principal studies on thermal fatigue on rocks come mainly from the field of geomorphology, particularly in connection with the analysis of the evolutions of past climate that can explain the present shapes of those landforms: those studies remained essentially qualitative and not quantitative. Le Ber & Oter Duthoit (1987) proposed a thermal and thermodynamic approach to analyse the disaggregation of rock masses. This analysis is dedicated to the study of paleoclimates and was implemented to better understand the formation of slope deposits in order to propose transfer models permitting the reconstruction of the climactic conditions contemporary to their appearance. Since deterioration in the cliff only appears after several cycles, it means that it is a gradual and irreversible deterioration which leads to an increase of the « disorder ». Seen from a macroscopic system point of view, this irreversible evolution is quantified by the internal creation of entropy."

Jan 1, 2015

By B. McFadzean, I. Achaye, T. Chidzanira, J. Wiese

"Froth stability has an overriding effect on metallurgical recovery and grade for many ore types. Froth recoveries of less than 10% are common for low stability froths such as those in sparsely mineralized ores or in cells at the back end of flotation circuits. It is well known that, aside from chemical factors such as frothers and electrolytes, the mineral particles themselves have the dominant influence on froth stability. The particle properties of size and hydrophobicity are expected to have the greatest effects on froth stability. The aim of this study was to understand the effects of particle size on froth stability and to quantify these relationships.The study compared a synthetic ore of pyrite and quartz, with carefully controlled size ranges and hydrophobicity, with conventionally milled platinum-bearing UG2 ore and the bulk reverse flotation of hematite ore. A novel bench-scale continuous column flotation cell and continuous mechanical hybrid cell with large relative froth volumes, as well as a three-phase froth stability column were used to characterize the froths.It was found that froth stability could be related to the concentrate particle surface area by a Langmuir-type relationship. This is indicative that the mechanism by which particles stabilize the thin films in froths is similar to the mechanism by which surfactants lower surface tension. Different froth stabilities were found for different ores and this was thought to be the result of different particle sizes and distributions, which resulted in different packing densities in the thin films and Plateau borders. Interestingly, there was a clear relationship between the feed particle size and the froth stability even though froth stability was dependent on the concentrate particle surface area. It seems that the feed particle size is a good predictor of the surface area of particles in the concentrate. Concentrate particle size did not show a clear relationship with froth stability since it was already shown that it is both the size and the amount of the particles in the froth that contribute to the stability.INTRODUCTIONThe stability of the froth in froth flotation is important to the recovery and grade of the valuable mineral. Too stable a froth and the grade is reduced; not stable enough and the recovery may be compromised. Platinum-bearing ores with fragile, poorly mineralised froths are known to have froth recoveries that are routinely less than 10% (Crosbie et al, 2009). There are a number of chemical, physical and operating parameters that can affect froth stability, including reagent dosages, air flow rate, pulp density and particle properties. Arguably, the largest contribution to froth stability is from the particles that stabilise (or destabilise) the thin films in froths. Particle size, hydrophobicity and shape all affect froth stability to some extent."

Jan 1, 2016

By E. Ghali, W. Zhang, M. Robichaud, G. Houlachi

"The performances of six mesh and one plate dimensionally stable anodes have been investigated in the zinc electrolyte at 38oC and compared to conventional silver-lead alloy anodes. The electrochemical behaviour of these anodes was studied by cyclic voltammetry, galvanostatic, potentiodynamic, open circuit potential and electrochemical noise measurements. It was observed that at the end of 24 h of galvanostatic polarization at a current density of 50 mA/cm2 in the zinc electrolyte at 38oC, the mesh V had the lowest potential followed by mesh III, mesh VI, plate-V, mesh IV, mesh I, and mesh II electrode. When the potentials for mesh I, mesh III, mesh IV, VI and plate-V, mesh V were compared with that of the Pb-0.7%Ag anode (1920 mV/SHE), they were found to be 6%, 16%, 7% 10%, 17% lower, respectively.After 16 h decay following the 24 h polarization, the mesh III had the lowest corrosion rate (51 mS/cm2) among the seven specimens, followed by the plate-V, mesh V, VI, IV, I and II (221 mS/cm2). For the fresh surface as received, after two hour open circuit potential measurements, mesh I had the most positive (noble) potential (1382 mV/SHE) among the seven electrodes followed by the plate-V electrode, mesh V, mesh IV, mesh VI, mesh III and mesh II (751 mV/SHE). After consecutive series of electrochemical testing, mesh V, mesh III, mesh VI had lower corrosion rates (~ 343± 6 µA/cm2) than that of mesh IV, mesh I, plate-V, and mesh II (~ 644± 143 µA/cm2).INTRODUCTIONThe continued use of lead based anodes in the electrowinning process has been mainly due to their relatively low cost as compared to other materials (Msindo, Sibanda, & Potgieter, 2010). They have good electrical conductivity, stability during electrolysis, very good corrosion and wear resistance (Ivanov, Stefanov, Noncheva, Petrova, Dobrev, Mirkova, Vermeersch, & Damaerel, 2010). However, lead-based anodes give their high energy consumption and low corrosion resistance for electrowinning. To overcome these problems, Dimensionally Stable Anodes (DSAs) has been chosen (Msindo et al., 2010). Comparing to the traditional lead anodes, the DSA anodes have many advantages: (1) no contamination; (2) no loss of anode material, pure electrolyte; (3) lower gas bubble effect through special anode designs; (4) use of higher current densities (Msindo et al., 2010). The success of DSA anodes has been attributed to their chemical stability that allows them to maintain nearly constant dimensions during the life of the anode even when operating in environment with low pH values. Due to their stability, the consumption rates of DSA are as low as 1 mg/amp.y (Alfantazi & Moskalyk, 2003)."

Jan 1, 2016

By BARRY BANNATYNE

Non-swelling bentonite has been quarried in Manitoba by Pembina Mountain Clays Limited since 1941. It occurs in several thin layers near the base of the Pembina Member of the Upper Cretaceous Vermilion River Formation, and is quarried from the narrow outcrop belt along the slope of the Manitoba Escarpment. It is marketed both as natural and activated bentonite for a variety of specialized uses. Percolation of acidic water through bentonite has produced a naturally activated bentonite with good absorbent properties; these properties are enhanced by treatment with sulphuric acid to produce an activated bentonitefor decolourizing petroleum and vegetable oil.

Jan 1, 1984

Recently, renewed interest in the recovery of uranium from leach solutions has necessitated a re-examination of the hydrometallurgy methods used for uranium in the 1960?s to 1970?s. A synthesizing overview of the lessons learned in those decades together with examination of recent developments in this area is warranted. This paper considers uranium recovery chemistry from acid and alkali leach solutions using solvent extraction and resin ion exchange, and provides information on circuit selection and configuration, equipment selection and design, as well as operational considerations. The unique thermodynamics of uranium solvent extraction are also presented and discussed.

Aug 1, 2010

By J. Koike

Mg alloys for structural application have attracted much attention. However, high process cost and poor mechanical reliability are major concerns upon expanding the application to a wider area. In order to break through these barriers, better ductility is desired at lower temperature. Plastic anisotropy and peculiar twin formation appear to play key roles in the deformation and fracture mechanisms of Mg alloys. In the paper, dislocation slip and twin formation are reviewed. The effects of crystallographic texture and grain size are discussed. The results suggest that a good control of microstructure and texture can improve ductility and mechanical reliability of Mg alloys.

Jan 1, 2006

By D. J. Sapsford

This paper details results from laboratory simulation of an innovative underground bioleaching process. The underground reactors are periodic flushed with recycled leachate to remove uranium that accumulates within the reactor water. This leaching cycle has been recreated within the laboratory. This study examines the influence of varying cycle protocol on uranium leaching. Protocol variants examined include variation of flushing frequency, flush volume, leachate recycle, nutrient solution (NPK) addition to reactors and Fe(III) sulphate addition to reactors. The presented data highlight the dramatic improvements in uranium recovery that might be achievable by varying the operating protocol for the actual underground reactors.

Aug 1, 2010

By A. M. Hadian

The use of dolomite refractories in steel making and cement industries has advantages over other basic products particularly in countries where this type of refractories is produced. Due to existence of high-quality dolomite deposits in many regions of Iran, there is a good potential for producing dolomite refractories in the country. This study focuses on the effect of such additives as iron oxide and alumina on hydration resistance and density of Iranian dolomite. It was found that addition of Fe2O3 is more effective than Al2O3 on increasing density as well as resistance to hydration of dolomite.

Jan 1, 2004

By Shamil Shaikhutdinov

CO adsorption on gold particles deposited on well-ordered alumina and various iron oxide films has been studied with temperature programmed desorption (TPD) and infrared reflection adsorption spectroscopy (IRAS). Structural characterization has been performed with scanning tunneling microscopy. Data show that the CO adsorption exhibits a size effect in that small particles adsorb CO more strongly. The effect generally vanishes after annealing to 500 K. For annealed samples, CO TPD and IRAS spectra are nearly independent of the particle size and supports studied. The results indicate that the CO interaction with gold surfaces is essentially similar and involves low coordinated atoms.

Oct 1, 2003

By M. Moats

World copper refining tankhouse practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in the 1987, 1991, 1995, 1999, 2001 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automatic anode preparation and cathode handling machines, section switches, fully automatic cranes and polymer concrete cells. General plant process control has increased with more automation of material handling in the copper refining tankhouse. The general trend for most greenfield copper refining projects remains in eastern Asia.

Jan 1, 2007

By F. Parada L

Two copper concentrate with medium and high enargite content were leached in a 3 L autoclave reactor under conditions based on the CESL process. Copper, arsenic, sulfur and iron were checked in all the experiments and antimony, zinc and molybdenum were evaluated in selected tests. The 98% of the obtained copper extraction is agree with others authors, but the behavior of arsenic, iron an sulfur have some differences. The solid residue was characterized by chemical analysis, DRX and QEMSCAN®. Finally a comparative analysis with neutral roasting as an option for the treatment of this concentrate is done.

Jan 1, 2014

By A. Fortin, C. Fréchette, M. Kreuh

Éléonore project is a gold ore processing plant at a mine site located near James Bay, Quebec, Canada. SNC-Lavalin was mandated by Goldcorp to perform EPCM services on the ore processing plant and permanent infrastructures of the project following an internal pre-feasibility study. The project incurred considerable challenges due to fast-tracking from a pre-feasibility to detailed engineering and construction. The paper reviews how the EPCM was carried out. Some of the challenges resulting from skipping the feasibility study stage are discussed. The paper also presents how multiple offices across Canada were used for the engineering design.

Jan 1, 2015

By Navid Bahrani

Introduction ? Today?s economic market is motivating underground mining companies to increase development advance rates and enhance their NPVs. ? For example, block cave mining involves development of kilometers of drifts with multiple pillars. ? The cyclic nature of drill and blast, and its inherent tendency to damage the surrounding excavation rock mass and increase support demand often result in poor advance rates ? This has motivated mining companies to replace the conventional drill-and-blast as the main excavation method with alternative methods such as mechanized excavation. ? There is little experience with mechanized or non-explosive excavation methods in hard rock metalliferous underground mining.

Oct 1, 2010

By J. C. Botham, T. D. Brown

"Coke is the most costly item in steelmaking via blast furnaces . Recent innovations in cokemaking have been directed toward reducing this cost while simultaneously improving coke quality and expanding the range of coals used in the process. It is also important to meet increasingly stringent environmental legislation.Improvements in coke quality have been achieved by novel blend selection procedures, by charge density control using both selective pulverization and partial briquetting, and by the use of modifying additives.The Canadian Carbonization Research Association provides a focus for Canadian cokemakin g research which has demonstrated these technologies in a series of pilot-scale experiments."

Jan 1, 1980

By P. E. Cavanagh

Abstract Many investigators have been interested in developing some non-destructive method for detecting or determining the changes in physical properties in steel occurring during endurance tests or normal service life of a part which fails in fatigue. This paper presents a broad discussion of some of this work and the possibilities of developing useful test procedures based on some of the information obtained in the past. Changes in magnetic properties, electrical resistance, damping capacity, X-ray diffraction patterns, and remaining fatigue life at load different from service load have all been investigated as possible means for following the sequence of events during fatigue failure. In some special instances, tests such as these may be used to predict fatigue failure. As an in stance of practical application of the continuous determination of changes in magnetic properties during fatigue, a brief account is given of work done in non-destructive inspection of mine hoist-rope. As a result of extensive experiments and field crisis, it has been found possible to detect the beginnings of failure in a wire rope in service. The test method used will detect plastic deformation in a wire rope, no matter what its cause. There is no possibility of determining the remaining useful life of a rope by calibrating changes in magnetic properties in terms of remaining fatigue life. A change in magnetic properties at a point in a rope may indicate a decrease or increase in fatigue life, depending on the overload history of the rope. A continuing change in magnetic properties ac a point, however, does reliably indicate a developing weak point which will eventually lead to failure. The important point about any change in magnetic properties is not the magnitude of the change, but whether or not it continues.

Jan 1, 1947