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By Jerry Gagnon, Matt Burr, Timothy Ellis, Abbas Mirza, Larry Webb

"The mechanical properties of RSR anode alloys (lead-calcium-tin, 009+ and lead-strontium-tin) were investigated as a function of time with an objective of developing lead anodes for use in high temperature electrolytic processes such as in copper liberator cells and in cobalt and nickel electrowinning. At a temperature of 70 oC, the mechanical properties of rolled RSR lead-calcium-tin (PbCaSn) alloy currently used in copper electrowinning decreased gradually while the mechanical properties of rolled RSR lead-strontium-tin (PbSrSn) decreased relatively quickly and stabilized at low strength levels. Cast PbSrSn started off as the weakest alloy but its properties remained stable with time. Rolled RSR 009+ anode alloy showed improvement in ageing properties over the other alloys tested. However, its mechanical properties did not stabilize in the study timeframe of 284 days. Further investigations are planned to study the effect of alloying elements on mechanical properties of RSR 009+ anode alloy over several years as a function of time at 70 oC. The mechanical properties will be evaluated to determine the time at which they stabilize. Comparative plant trials with rolled RSR PbCaSn and RSR 009+ will also be performed in copper liberator cells and in cobalt and nickel electrowinning tankhouses to determine their mechanical and electrochemical performance at temperatures of 65-75 oC.INTRODUCTIONLead-based alloys are the primary anodes used in the electrowinning of copper, zinc, nickel, cobalt and manganese from sulfate-based aqueous systems. Lead anode technology has evolved over the years migrating from pure lead and lead-antimonial alloys to the present day PbCaSn alloys for copper and PbAg and PbCaAg alloys for zinc electrowinning (Prengaman, Ellis and Mirza, 2010). It has also migrated from cast to rolled microstructures in search of improved mechanical properties and higher corrosion resistance. Although great strides have been made in the development of new lead anode alloys and production processes for lead anodes to be used in copper electrowinning, the industry still has some unresolved issues. These relate to the necessity of having higher mechanical properties especially for the lead anodes in liberator cells in copper electrorefining and for cobalt and nickel electrowinning as these tankhouses operate at temperatures of 65-75 oC compared to 40-45 oC in case of copper electrowinning."

Jan 1, 2016

By C. G. McLachlan

Professor H.E.T. Haultain: To me from time to time the urge comes to say the agreeable thing as well as the disagreeable in commenting on the work of others. It is a prerogative of age. I don't apologize. To myself I justify my action as based on a long experience of the matters with which I deal, and I like to tell myself that I have a certain responsibility in such matters on account of my detached position. This Noranda article is a very fine contribution concerning Canadian milling, and I am surprised that no word of commendation or thanks has appeared concerning it in the BULLETIN. There is altogether too much written in these days by men rushing into print, concerning laboratory work, that has not been tied into, nor has resulted in application in the field. The authors of this paper have not rushed into print. The preparation of this paper was evidently an uncongenial task. If the authors had been that way inclined, it could have spread over several lengthy papers. It is an important article because it represents an enormous amount of work in the laboratory and the mill, extending over a period of sixteen years, and resulting in fine metallurgical and economic results with a very difficult and involved problem. It is a fine article because it is so well prepared and presented. It deals with an unusual ore condition, but there is much in it of use to every cyanide millman. It leaves very little room for criticism, though there may be differences of opinion in regard to some of the chemistry phases with which I am not conversant. I am struck by the enormous amount of persistent, painstaking, conscientious research work involved, and in the careful, sincere way in which the methods and difficulties have been described. Persistence and sincerity are the key note of the effort. It should have a good educational effect on the rising generation of millmen, and it should continue for long as a work of reference, and a spur to others. There has been an important by-product, the training and development of the young men engaged in the work. Three of them became superintendents of important mills. One was sought for important work in Africa, another has joined a large research organization in the United States.

Jan 1, 1946

By Dan Alexander, Ivan Crnkovic, Sarah Schwarz

"Several plant studies have been conducted at the Zinifex Century Mine over the past 5 years. For each of the plant studies, surveys of the zinc primary circuit were conducted, characterisation measurements for each operating cell taken, and the floatability components of the ore mapped to develop a model of the circuit. The floatability components and machine parameters were then used to simulate changes in circuit configuration and operating conditions, enabling further potential improvements in circuit performance to be identified.This paper reviews the current flotation practice at the mine, as well as various circuit changes and developments implemented by site. The application of the methodology and the evolution of the standard procedure are also discussed.INTRODUCTIONBase metals were first discovered in the Lawn Hill region of Queensland’s North West in 1869 and the first mining lease in this area was pegged in 1887 over what is now known as the Silver King vein deposit. The area encompassing these veins, which includes the Century deposit, was proclaimed the Burketown Mining Field in 1899. Exploration titles were granted to CRA in 1987, precisely 100 years after the initial discovery at Silver King, hence the name ‘Century’.Century was commissioned by Pasminco in late 1999, with the mine becoming fully operational on 1 March 2000 and the official opening taking place in April. Pasminco had bought the Century and Dugald River deposits from CRA in 1997 for A$345 million, and invested some A$710 million in bringing Century into production. Today, Century is the world’s second-largest zinc mine in terms of its output, having reached full capacity in 2003.The Zinifex Century Limited (“ZCL”) lead-zinc-silver deposit is located approximately 250 kms north-north west of Mt Isa in north-western Queensland. The deposit is a large flat-lying ore body covering an area of some 1.2 by 1.4 km, the 45 m-thick stratabound sulphide orebody is hosted within an 850 m-thick sequence of Proterozoic siltstone, shales and sandstone, amenable to open-cut mining methods. The mine has ramped up to full production delivering five and a half million tonnes of ore per annum, yielding approximately 900,000 tonnes of zinc concentrate and 90,000 tonnes of lead concentrate. Mine life is expected to be about 8 years"

Jan 1, 2008

By Eric Toh, Michel David

"Geo-statistics was born from mining problems: grades not being what was expected; more tons of waste than expected; in other words, dilution. Geo-statisticians now claim to have solved many of these problems, but the solutions seem to have a hard time being picked up by practitionners. One of the reasons may be the jargon which geo-statisticians are using. The reason for jargon is that obtaining solutions required a strict formulation in a statistical framework. Practicing mining engineers and geologists are not used to such a framework, and they are not familiar with the jargon. In this paper, the authors re-examine dilution in operating mines and answer two extremely practical problems, using practical language as much as possible. Can dilution be reduced by improving the quality of blast hole samples? How many samples are needed to obtain a good ore-waste discrimination, i.e. to reduce dilution to acceptable levels? Citing real situations, this paper will try to show how fairly simple concepts can be used to answer both problems. It will try to present the solut ions using a minimum of jargon, even if the theoretical solution could be obtained in a few precisely worded paragraphs.The two problems considered are the following: the first one was encountered in the Panguna deposit of Bougainville Copper Limited, P.N .G., but it occurs in every open pit operation where selective mining is required. As the cut-off is lowered, more and more mining occurs in marginal areas. Grade control is mostly based on the grades obtained from blast holes, hence, it is essential that the quality of the blast hole samples be as good as possible in order to reduce dilution, waste being sent to the mill and ore being sent to the waste dump.The second example stemmed from the grade control technique used in many gold open-pit operations in Western Australia: channels are cut on lines 5 m apart and assays are taken every metre. The pattern in the same regardless of rock type, whether one is in the oxidized zone or not. The number of samples to be treated is enormous, hence, the question arises how to find an acceptable sampling grid, and whether changing it can reduce dilution at an acceptable cost.A solution will be given to each problem separately, although in fact it could be seen that the formal framework is the same in both situations."

Jan 1, 1989

By T. E. Smith

"This paper describes the application of a motor-driven flywheel unit, known as a peak shaver, to compensate for the cyclic load fluctuations of a large electric dragline installed at Pine Point Mines, near Great Slave Lake in the Northwest Territories. Of particular interest in this application is the fact that the power system supplying the dragline is a relatively small isolated system, with the major generating source approximately 170 miles from the mine.The cyclic load fluctuations of the dragline are theoretically capable of producing a maximum swing of up to 11 megawatts, which approaches nearly 50% of the installed generating capacity. To reduce these load fluctuations to acceptable limits various alternatives were considered, leading to a decision to install a peak shaver to optimize the operations of both the mine and the power system. Without the peak shaver, the dragline operations would be severely curtailed and additional diesel generation would have to be run at considerable expense, otherwise the power system frequency fluctuations would be totally unacceptable. With the peak shaver, power and frequency fluctuations are kept within tolerable limits, and optimum economic operation of the diesel generation is obtained.The paper outlines the steps leading to the selection of the peak shaver as the compensating device, describes the equipment installed and gives details of operating experience with the dragline/peak shaver combination since installation early in 1979. This .peak shaver is the first of its kind in North America, the only other peak shaver installation being in Australia.IntroductionPine Point Mines Limited owns zinc-lead mining and milling operations located at Pine Point, Northwest Territories, 5 miles south of Great Slave Lake (Fig. I). The company is staffed and managed by Cominco Ltd., which has a 69% interest in Pine Point Mines.Mining activity in the Pine Point area was first recorded in 1898, when the Yukon gold rush was on, but when the zinc/lead showings in the Pine Point area did not yield much in the way of gold, interest in the area soon waned. Cominco Ltd. first acquired some claims in the Pine Point area in 1928, but interest was sporadic until the early 1950s, when extensive exploration indicated rich pockets of zinc/lead ore near the surface. Pine Point Mines Limited was formed in 1951, with Cominco acquiring a majority interest in the company."

Jan 1, 1980

By Colin Hardie, Simon Pelletier, Rakan Rhabani, Guy Comeau

"In order to improve the nickel concentrate thickener operation at Raglan Mine, two pulp deaeration cyclones were installed. These units obtained from Outotec Pty Ltd, also called the FrothBuster®, have been in continuous operation since mid-October 2006. The primary objective of the de-aeration cyclones is to lower the solids content in the thickener overflow by de-aerating the concentrate pulp before it enters the concentrate thickener. This dearated slurry should help decrease the nickel particle losses that report to the thickener overflow because of the flotation effect within the thickener.Optimizing the de-aeration cyclones has been a slow and ongoing process, however, initial testing is encouraging. The latest test results indicate a 50 % reduction (0.070 to 0.035 % solids) in nickel losses to the concentrate thickener overflow resulting in an additional $350,000 in annual revenues.This paper will present an overview of installing the de-aeration cyclones within a limited space, as well as the preliminary commissioning and testing challenges. This paper will also discuss the most recent concentrate thickener operating results since the de-aeration units were installed.INTRODUCTIONThe Xstrata Nickel Raglan Concentrator, located at the northern limit of Quebec’s Nunavik Region has been in production since 1997. In early 2002, the concentrator implemented the Zero Process Water Discharge (ZPWD) project to recycle the process water to decrease fresh water consumption and reduce discharges to the environment. Due to this initiative, the chemistry of the process water changed significantly resulting in flotation concentrate streams, which were very frothy and difficult to manage. This phenomenon has resulted in operational challenges in many areas of the concentrator including slurry pumping, flow measurement and concentrate thickening.In October 2005, the Raglan Mine underwent a conversion from an AG mill to a SAG mill operation in order to increase throughput and to optimize key process areas. As part of this project, the first two North American pulp de-aeration (FrothBuster®) units from Outotec were installed to improve the operation of the concentrate thickener. The primary objective of the deaeration technology was to lower the solids content in the thickener overflow by de-aerating the concentrate thickener feed pulp. This in turn was to reduce the froth, which accumulates on the thickener surface, and more importantly reduce valuable nickel losses to the thickener overflow because of the flotation effect within the thickener."

Jan 1, 2008

By Ross Gilders, Leo Cheung, C. David Desjardins

"For the past twenty years significant progress has been made in bacterial leaching. In fact, a recent article in the Northern Miner has cited that nearly all new copper production is based on bioleaching. The bacteria that play the predominant role in bioleaching is an obligate chemolithoautotroph called thiobacillus ferrooxidans. These bacteria thrive in areas rich in sulphide and prefer low acid media. In the simplest sense, they metabolize sulphide converting it to sulphate either as acid or as soluble metal sulphates. This process is well known because these bacteria generate acid mine water. Over the last five( 5) years, we have been carrying out development work on creating optimum bioleach conditions for the extraction of metals from sulphide rich ores and concentrates. Recently, a study was carried out on a byproduct sulphide concentrate produced in a tin flowsheet developed for the Mt. Pleasant Mine of ADEX Mining Corp. The objective was to determine whether a bioleach process might successfully leach this sulphide material which contains copper, zinc, iron and, what is more important, trace metals such as Indium, Gallium, and Bismuth. The current work describes the successful recovery of these metals achieving extractions of more than 80% by applying bioleaching techniques. An overview of this technical program forms the basis of this paper.IntroductionBio-Oxidation of metal sulphides has emerged to be one of the leading edge hydrometallurgical processes for the economic extraction of metals from ore and concentrates. The fundamental process involves the bacterial assisted oxidation of sulphide to sulphate yielding metal sulphates which can be subsequently leached by conventional means. The bacteria that play the predominate role is an obligate chemolithoautotroph named thiobacillus ferrooxidans (TF). These bacteria thrive in areas rich in sulphide and occur naturally worldwide. In fact, TF is responsible for generating acid in water (acid mine water) from exposed sulphide surfaces primarily through the oxidation of pyrite. TF bacteria thrive under the proper conditions of temperature and oxygen supply in the presence of sulphides and populations in excess of a million per millilitre (ml) of solution are achievable. Typically, at room temperature, the bacteria will bio-oxidize in a pH range of 1.0 to 3.0. Today, bio-oxidation has been applied commercially with great success for the extraction of uranium, copper, and gold."

Jan 1, 1996

By A. Probst, N. Moores, J. A. Finch

"In 1994 McGill and INCO (Sudbury operation) initiated transfer of technology originally developed to detect level in flotation columns to thickeners. A conductivity probe was installed in a concentrate thickener to monitor the mud-line and solids load. The probe consisted in a vertical tube with 32 equally-spaced electrode rings connected in pairs to give 31 conductivity cells. Conductivity was measured as a function of depth (so-called conductivity profile) from which the mud line and % solids could be inferred. The probe was installed in October 1994 and has been successfully detecting profiles since then. This communication includes a description of incidents and experiences during this technology transfer process including: probe installation and start-up; software modifications to accommodate operating conditions and operators' needs; calibration procedures to adjust to changes in performance as a consequence of long term use; and preliminary observations on the last stage, still in progress, signal interpretation and use to facilitate operation, particularly by providing early reaction to upstream disturbances.IntroductionThickening is one of the basic unit operations in mineral processing and hydrometallurgy used to separate suspended solid particles from a solid-liquid dispersion by gravity settling. As the dispersion enters the thickener, the solids settle and clarified water overflows the top. A thickener, which may be continuous or batch, is basically a large vertical cylindrical tank provided with devices to feed the dispersion and to remove the settled solids. The tank provides residence time for the particles to settle. The dispersion enters the thickener through the feedwell whose function is to dissipate the momentum of the feed stream and to create relatively quiescent conditions around the entering point. Rotating rake arms move the settled solids towards the discharge point located at the bottom centre of the tank.There are normally three distinct zones in a thickener: a top layer of clear water, a middle layer called a sedimenting zone in which particles are settling, and a bottom layer called a compression zone in which particles are pressed together as a consequence of the weight of accumulated particles. Proper operation of a thickener requires two simultaneous conditions: no solids in the water overflowing the top and the target solids content in the underflow pulp. To achieve these conditions is difficult because sensors for detecting the sediment line (interface between clear water and sedimenting zone) and the solids content in the compression zone are not commercially available."

Jan 1, 1998

By A. Roca, V. A. Quezada, O. A. Benavente, M. Cruells

The leaching pretreatment of copper ores is widely used in the Chilean mining industry. Agglomeration and acid curing have been identified as the most useful pretreatments. Of these, acid curing was recognized as beneficial in the dissolution of copper minerals, even in sulphides such as chalcopyrite. Extensive acid curing times have an impact on copper extraction, generate a homogeneous acid distribution in the mineral bed and benefit the inhibition of aluminum-silicate minerals (acid consumers). This document describes some of the theoretical background and results regarding the effect of acid curing in a chalcopyrite sample with 74% purity according to Qemscan analysis and a 28.5% of total copper. Leaching tests are carried out at 25, 50 and 70°C, evaluating the effect of a pretreatment on the chalcopyrite dissolution. The original sample and products generated were characterized by X-ray diffraction analysis and Scanning Electron Microscopy (SEM). The performed experiments indicate a direct relation between the effect of curing time and temperature in copper extraction. 92% of copper can be extracted in a leaching at 70°C and with 15 days of curing. Elemental sulfur, jarosite and copper polysulfide (CuS2) have been detected in leaching products. INTRODUCTION The copper extraction from minerals is a technique that has been developed for hundreds of years in the world. In 2017, the largest copper producer was Chile, exported 5.5 million tons (COCHILCO, 2018). However, in order to preserve this production level means overcoming multiple challenges. In the case of the Chilean copper deposits, the average copper grade in 2016 was 0.65%, lower than the 1% declared in 2004 (Consejo Minero, 2018). This is mainly due to the deeper of the deposits reaching sulfide mineral zones, mainly chalcopyrite. Traditionally, these sulfurized zones ore are treated through concentration by flotation and subsequent pyrometallurgical treatments. However, for some copper companies it is complex to process by this alternative, due to the high costs and high rates of water consumption. The mineral resources of these companies are known as "low-grade sulfides" and do not allow, economically, the treatment of these minerals through concentration by flotation. This is how hydrometallurgy becomes an alternative for the treatment of this type of deposits. In addition, several companies have hydrometallurgical plants, which would allow the operational continuity of these plants.

Jan 1, 2019

By Jacques H. Nantel, James F. Archibald

"Frozen tailings material may be required, in the future, to perform the support functions of underground backfill in mines located in zones of permafrost, notably in the high Arctic. To date, no knowledge of physical support parameters of such materials has been obtained in Canada due to the limited mining activity in permafrost regions. It is therefore judged essential that the important physical and mechanical properties relating to frozen tailings material be assessed.Innovative mining methods will be required to cope with the harsh environmental conditions that exist at mining sites in the Canadian Arctic. A preliminary laboratory study, in the absence of field trials at limited Arctic mining sites, has been completed in which the physical and mechanical properties of several types of representative mill tailings mixtures have been investigated. A variety of tests, to determine frozen slurry and pelletized tailings strength properties, moduli of compression, optimum water contents, deformation characteristics and the like, have been conducted.The results of this study will be used to establish guidelines for the suitability of tailings use in such northern mining environments. IntroductionFrozen tailings material has never been used to backfill underground openings in Canadian mines. At present only one Canadian mine, the Polaris Mine situated on Little Cornwallis Island, is investigating the use of frozen backfill. However, the Canadian North covers a large territory and potentially contains a large number of mineral deposits. The understanding of concepts related to mining activities in sub-zero frozen ground is therefore important.The implications of using frozen tailings as underground backfill material are far reaching both from the point of view of mine stability and disposal of tailings in the arctic regions.The strength of frozen materials (soil, backfill, etc.) may take on different meaning depending on the engineering situation. Both the concepts of rupture and excessive deformation need to be considered.The functions usually required to be performed by the backfill material in underground mines may be summarized asfollows:a) working floors; such as in cut-and-fill stopesb) stope wall support; for cut-and-fill and delayed fill stope~c) self-support when backfill is exposed on one face; during pillar recovery phases.For fill functions such as working floors, the short-term response of the frozen fill is the dominant concern. For the other fill functions, the long-term deformation response of the frozen fill, or creep, is of interest."

Jan 1, 1986

By C. A. Sutherland

"Smelting of copper-gold ore from nearby Rossland mines started at Trail in the 1890s. As ore from the Rossland mines became exhausted, lead smelting offhand-sorted galena orefrom other British Columbia mines was initiated. With the development of flotation technology for the separation of lead, zinc, and iron sulphides in the first two decades of this century, the large Sullivan orebody at Kimberley, British Columbia, became the foundation for the growth of a major zinc and lead smelter at Trail. Lead smelting began in 1901, electrolytic zinc in 1916, and by 1984, the Trail metallurgical complex had produced 10 million tons of each metal. Its present capacity is 270000 tonnes per year of zinc and 110 000 tonnes/year of lead.This paper reviews the history of technological changes in the Trail production plants, emphasizing the zinc plant modernization program started in the 1970s, and also the planned introduction of the QSL oxygen lead smelting process in the late 1980s. Lead modernization will increase production capacity to a maximum of 160000 tonnes per year.IntroductionCopper-gold ore was discovered at Rossland, British Columbia, in the year 1890, starting a mining industry that was to last over three decade s. Selected ore was at first transported at high cost to distant U.S. smelters, so there naturally followed a decision to construct a small copper smelter to process the local ore to matte. It was built in 1896 at the mouth of Trail Creek on the Columbia River, about 10 km from Rossland. This little smelter was to develop and diversify in the next 90 years into the world's largest lead-zinc produce.The mining boom that occurred in the northwestern United States and southeastern British Columbia in the period of 1890 to 1910 saw the brief operation of many small local smelters. The only one to survive was the smelter at Trail. The circumstances that permitted its continued life and subsequent growth, form a fascinating history of business deals, litigation, and steady technical progress.Early investment in local railway transportation and options by F.A. Heinze, the smelter' s founder, attracted the attention of the Canadian Pacific Railway Company, which purchased Heinze' s assets in 1898. This provided the capital base for survival and growth of the smelter, which remained and prospered under the Canadian Pacific umbrella for almost ninety years. It was registered as the Consolidated Mining and Smelting Company of Canada Limited in 1906; in 1966, this name was shortened to Cominco Ltd."

Jan 1, 1988

By J. M. Hollicky

The economical processing of wet and sour natural gas presents a problem due to the seasonal demand for natural gas. The plants must be sized to handle the peak loads but may only operate at half capacity on the average, in which case the sales value of sulphur and hydro-carbon liquid by-products cannot support the operating and capital costs of the plant. This must result in an increased price for the gas. This problem was solved by Pacific Petroleums and Westcoast Transmission in the design of their pipeline and plant facilities now operating in the Peace River area, where there are both wet and dry gas fields. By .building a plant to process sufficient wet gas to pro-vide the base load requirement, and by drawing on the dry gas fields for peak loads, an optimum economic operation was ?possible. The sulphur, L.P.G., and gasoline produced not only are able to support the operating and capital costs of the pro-cessing plant, but were instrumental in the sharp drop in retail prices of these commodities in the area. The sour gas and condensate is gathered from the fields in the area and transmitted in a two-phase gathering system to the gas processing plant at Taylor, B.C. The condenrnte is knocked out in inlet scrubbers. Hydrogen sulphide and carbon dioxide are removed in an amine scrubbing unit. The hydrogen sulphide is stripped from the amine and is sent to the Jefferson Lake Sulphur Company's plant which produces sulphur by the partial oxidation of the hydrogen sulphide. The natural gas, now sweet, is processed in an absorption unit to recover additional liquids, before being de-hydrated to remove water. It is then sent to Westcoast's main c8mpression station. The condensate recovered in the inlet scrubbers and the liquid re-covered in the absorption unit are fractionated to remove fuel gas, used in the plant, and to produce pro-pane, butane, and naphtha. The pro-pane and butane are scrubbed with caustic soda to remove hydrogen sulphide. The naphtha is treated with hydrogen in a unifiner unit to re-move sulphur compounds completely, and is split into a light and heavy naphtha. The heavy naphtha is .catalytically reformed to produce a high-octane blending-component. These fractions are blended with components produced from crude oil at the Dawson Creek refinery to produce a high-quality balanced gasoline with special attention being paid to volatility for ease of starting, warm up, and engine cleanliness, and octane for power and ?performance.

Jan 1, 1958

By R. Bruce Ferguson

"The Kettle River Operation of Echo Bay Minerals Company is located about thirty kilometers north of the town of Republic in northeastern Washington State. In tum, Republic is about a hundred and seventy kilometers north and a little west of the city of Spokane, Washington. It is also about fifty kilometers south of the town of Grand Forks, BC, Canada. At this time it is the only gold mining and milling operation in the State.Tailings are stored in a double lined, zero discharge facility. It became evident in mid 1996 that the rate of free water accumulation in the tailings pond was going to result in the level in the pond reaching its permitted freeboard elevation long before the solids plus pore water capacity was reached.We then embarked on a mission to manage tailings pond water on several fronts: reduce fresh water usage in the process, divert spring seeps and surface runoff and install a system to enhance evaporation.IntroductionThe Republic area is an historic gold mining district. Hecla operated its Republic unit from 1892 until closure in 1994. The Kettle River Operation processing plant is located in the San Poi! river valley at an elevation of just under a thousand meters. The facility consists of a ninety thousand ton ore storage pad as the mines are remote and truck haulage is subject to interruption due to weather and road restrictions, jaw and cone crushing with screening, rod and ball milling to an eighty percent passing size of seventy five microns. This is followed by preaeration with high purity oxygen supplied by a vacuum pressure swing adsorption plant plus lead nitrate addition to achieve passivation of the sulfide mineralization such as chalcopyrite, pyrite and pyrrhotite. Conventional cyanide leaching and carbon in pulp adsorption completes the loop. Tailings are treated with air/S02 to achieve cyanide destruction. Plant capacity is 1,815 tons per day. Our license requires that there be no detectable free cyanide in the tailings pond water and a maximum of forty parts per million weak acid dissociable cyanide. The operation started in 1989 with production from the Overlook Mine located about five kilometers further up the same valley at an elevation of twelve hundred meters, hence the location of the mill. Current mine production comes from Lamefoot in the Curlew Lake valley, about ten kilometers distant, and K2 in the Kettle River valley about fifty kilometers away. Both are at an elevation of about 800 meters. Lamefoot produces 1,360 tons per day and K2, 455. Both are underground operations."

Jan 1, 1998

By A. Deneys

This paper reviews industrial gases used in primary copper production. Copper smelting industrial gas demand has steadily increased since the first commercial oxygenconcentrate smelting in 1952 [1]. In copper production oxygen for smelting is the dominant industrial gas use followed by oxygen for converting. Nitrogen is finding increased use in copper smelters. Nitrogen is used for porous plugs for copper converting and anode refining [2-5]. Nitrogen can be used for concentrate drying [6,7] and is also used in some Ni-Cu smelters as a coolant in Peirce-Smith converting [8,9]. Industrial gas supply options of cryogenic or adsorbent based on-site plant or cryogenic liquid delivery are detailed.

Jan 1, 2007

By S. Caron, P. Radziszewski

Industrial practice in mineral processing shows that an important problem in understanding and monitoring in-mill parameters is due to the lack of fundamental knowledge and appropriate sensors. However, over the last decade, Discrete Element Method (DEM) modelling has shown an interesting potential in describing the fundamentals of grinding mill behaviour, in improving the understanding of internal grinding mill dynamics, and in developing solutions to industrial practice. With the objective of bringing this modelling technology into the concentrator control room to assist operators, this paper aims to describe the main elements needed to apply this emerging and developing technology to on-line mill performance monitoring.

Jan 1, 2004

By Jeremy D. Glennon

A number of exciting challenges, opportunities and unanswered questions remain concerning the chemistry, geochemistry, medical, industrial and analytical applications of gold and its compounds.1 Among the challenges presented is the need for extraction methods for gold, at process and indeed analytical scales, that avoid the use of organic solvents or hazardous reagents. Extensive environmental contamination has occurred in the Brazilian Amazon from the mercury-gold amalgamation process. Major problems with the cyanidation process are the relatively slow dissolution kinetics and the health and environmental problems associated with it. With innovation and technical changes, a cleaner way for solubilising and extracting this versatile precious metal can be found. This cleaner future may lie in supercritical fluid science. Interestingly, geochemical studies of gold solubility and speciation in hydrothermal solutions have highlighted the importance of supercritical conditions and sulphur species in the deposition of gold in natural environments. Gold solubility in supercritical brines is far higher than previously supposed while interest in the high content of carbon dioxide in the mineralizing fluids is growing. 2,3 In recent years, also, there has been a tremendous amount of attention paid in analytical chemistry and in industry, to the area of supercritical fluid extraction (SFE) of organic and metallic species. 4 This interest has been fuelled by the introduction of more stringent environmental control and the subsequent need for cleaner solvents and processes to replace established ones. Carbon dioxide is the substance of choice for SFE because of its moderate critical parameters (Tc = 31oC, Pc = 73atm), inertness and availability in pure form. It is an excellent extraction medium for non-polar and moderately polar species, and with careful ligand design, it can be used for analytical and process scale metal extraction from solution and solid phases. In general, the dissolution of a metal in supercritical CO2 (sc-CO2) requires that the charge on the metal ion be neutralised on complexation by the ligand or through a form of ion pairing (analogous to the situation where metal ions are extracted into organic solvents, such as methyl isobutyl ketone or toluene). In this way, then, many chelating agents such as dithiocarbamates and hydroxamic acids have been utilised to extract metal ions such as Cu and Fe into sc- CO2, the process greatly enhanced by the use of fluorinated ligand derivatives. 5-7 In this review paper, we show that supercritical conditions and complexation with sulphur donor atoms, important in the natural deposition of gold, can form the basis of a clean, eco-friendly chemistry for gold extraction. Analytical scale extractions of gold from a variety of matrices can be conveniently used to assess the efficiency of any new proposed ligand.

Oct 1, 2003

By John H. Walsh

"ForewordPart I of this paper, published in the March 1992 issue of the CIM Bulletin, surveyed the probable consequences of a limitation on the emissions of carbon dioxide to the atmosphere for the steel industry. What might be termed the conventional responses to this restriction open to the industry were also surveyed in that section. This section, Part II of the paper, explores a new option - the possibility for the joint production of iron and liquid fuels useful for transportation purposes. In this case, it is shown that it is important to minimize the production of carbon dioxide during the reduction stage to maximize the proportion of the reductant carbon embodied in the fuel. It is also advantageous to conserve hydrogen in the reduction step. In essence, the same carbon fulfills two purposes: it serves as a reductant and fuel for ironmaking and then as a constituent of a liquid fuel. If recovered plastics could be used in ironmaking, the same carbon could serve three useful purposes in turn. The conditions and limitations for the joint use of carbon in such 'cascading' processes are explored below. ABSTRACTIt is becoming increasingly probable that emissions of carbon dioxide from the fossil fuels will have to be reduced to deal with the threat of global warming. This issue is likely to be resolved one way or the other in the period 1995 to 2000 which does not leave much time to develop responsive options. In the intervening period, the policy of the Government of Canada is to stabilize emissions of greenhouse gases at their 1990 level by 2000, by encouraging greater efficiency in the use of energy. Should further reductions prove necessary, economic instruments would probably be employed but these would not be applied before a comprehensive international agreement is reached.There are three main themes in this paper: it is assumed that measures to control carbon dioxide emissions will in fact be necessary by the turn of the century; that there will be a rising need for liquid fuels to supply the world's steadily growing fleet of motor vehicles for many years to come, and that the future niche for Canada's industry in such a carbon-constrained world will be the operation of the energy-intensive industries with efficiency and environmental sensitivity.The steel industry, as a large user of both coal and energy in other forms, would be significantly affected by a need to reduce carbon dioxide emissions. This paper first examines what might be called the conventional responses open to the industry in such a situation and then explores a new possibility for making better use of carbon by the co-production of iron and liquid fuels."

Jan 1, 1992

By S. McPherson, M. Chalkley, R. Ellenwood, W. Nicot

"The Moa JV was formed in December 1994 as a 50/50 joint venture between Sherritt Inc. and General Nickel Company S.A. of Cuba. The joint venture consists of the mine and Pedro Sotto Alba processing plant in Moa, Cuba and the Corefco refinery in Fort Saskatchewan, Alberta, Canada. Throughout its now nearly 23-year history, the Moa Joint Venture has faced a number of global, operational and process challenges. Global challenges have included high input costs such as for fuel oil and sulphur, as well as low nickel prices. Operational and process challenges have included increasing ore haulage distances, decreasing ore Ni + Co grades, and increasing ore impurity contents. For example, increases in impurities such as Mg and SiO2 in the ore result in increasing acid demand in leaching and decreasing solids content of preheated leach feed slurry, respectively. In spite of these challenges, the mixed sulphide production capacity from the Moa Joint Venture has increased from 12,500 to 37,000 t/y Ni + Co since 1994 by judiciously targeting expansion projects and by continuously performing process and operational improvements.INTRODUCTION The Pedro Sotto Alba high pressure acid leach (HPAL) plant at Moa Bay, Cuba has a long history (Maslenitzkiy, 1969; Chalkley, 1996; Carlson, 1960; Roy, 1961; Carlson 1961). The plant was constructed by Moa Bay Mining Company and started up in late 1959 after several years of process development by Freeport Nickel Company, including operation of a 10 t/d plant in Hoskins Mound, Texas and a 50 t/d plant in Port Nickel, Louisiana (Southwick, 2004), as well as development work by Chemical Construction Company (Chemico) to precipitate metal sulphides (Roy, 1955a; Roy, 1955b). The Moa plant had an original reserve of 50,000,000 t of ore, graded at 1.35 wt% Ni, 0.146 wt% Co, 3.70 wt% Si, 1.00 wt% Mg and 4.5 wt% Al. At original design rates of 2,000 kt/y of ore, the design capacity of the plant was around 25,000 t/y Ni + Co as a mixed sulphide product, which would be shipped to the Port Nickel Refinery in Louisiana for processing. In 1960, the plant changed ownership and was restarted in 1961 under Cuban management. Between 1961 and 1989, the plant was also supported by involvement from the former USSR, supplying spare parts and consumables. In 1994, Sherritt Inc. partnered with the General Nickel Co. S.A. of Cuba and formed the Moa Joint Venture. This joint venture includes the mine and Pedro Sotto Alba HPAL processing plant in Cuba and the Corefco refinery in Fort Saskatchewan, Alberta, Canada. Under this partnership, ore is processed in Cuba to produce a nominally 55 wt% Ni and 5 wt% Co mixed sulphide product that is shipped to Canada and processed by Corefco to produce class 1 nickel, high grade cobalt and byproduct ammonium sulphate fertilizer."

Jan 1, 2017

By T. H. Chuang, Y. Y. Shiue

"Rapid whisker growth was significantly alleviated in a Sn-58Bi alloy doped with 0.5 wt.% La. Experimental results showed that many thin, plate-form intermetallic phases appeared in the solder matrix. The absence of tin whiskers was correlated to the shape effect of RE-containing intermetallic plates. After reflowing, Cu6Sn5 intermetallic compounds appeared at the solder/pad interfaces of Sn-58Bi and Sn-58Bi- 0.5La packages with OSP pads, which grow linearly during the aging at 75 and 100? for various times ranging from 100 to 1000 h. In addition, the interfacial intermetallics layers in Sn-58Bi-0.5La solder joints were also observed thinner than those in undoped Sn-58Bi joints. However, RE-containing interfacial intermetallic compounds in Sn-58Bi-0.5La solder joints led to lower bonding strengths in both ball shear tests (0.4 mm/s) and high speed ball shear tests (2000 mm/s). All the reflowed and aged solder joints of both packages were ruptured through the solder balls indicating brittle characteristic INTRODUCTIONIt has been widely reported that solder alloys doped with rare earth (RE) elements reveal many beneficial effects, such as higher strength, lower melting point, improved wettability, and longer creep life (Wu et al., 2004; Ma et al., 2002; Chen et al., 2002). In addition, Dudek et al. reported that the alloying with 0.5 wt.% La in Sn-3.8Ag-0.7Cu solders resulted in an increase of rupture strain, up to 150% over undoped solders (Dudek et al., 2006). However, Chuang and Yen observed that a large amount of long, fiber-shaped tin whiskers were extruded out of the oxidized CeSn3 intermetallic clusters in the matrix of a Sn-3Ag-0.5Cu-0.5Ce solder air-stored at room temperature for several days (Chuang & Yen, 2006). Furthermore, many coarse hillocks appeared around the CeSn3 clusters in the RE-doped alloy after storage in an air furnace at 150? for several minutes. Chuang proposed a mechanism for the phenomenon of rapid whisker growth, which the predominate oxidation of CeSn3 intermetallics in Sn-3Ag-0.5Cu-0.5Ce solders induced compressive stress and extruded the tin atoms out of the specimen in the form of tin whiskers (Chuang, 2007). However, further investigation showed that Sn-9Zn-0.5Ce solders, after long term exposure at room temperature and 150?, were immune to the whisker growth; the immunity was attributed to the refining of the CeSn3 intermetallic phase in the alloy (Chuang & Lin, 2008). The inhibition of tin whiskers through the refining of rare earth containing intermetallics was further observed in Sn-3Ag- 0.5Cu-0.5Ce solders doped with 0.5 wt. Zn (Chuang & Lin, 2009). In addition to the size effect, the thin plate shape of intermetallic compounds was also shown in this study to inhibit the whisker growth on the surface of Sn-58Bi-0.5La solders."

Jan 1, 2012

By C. E. Baltzer

This paper highlights the position of coal supply in regard to the requirements for electric-utility operations. The text and the appended tables outline the trend of thermal power development and fuel use in the electric-utility industry. Mention is made of several argumentative factors influencing the use of coal in relation to competitive oil and gas, and of the importance attached to developing a realistic understanding of the respective problems faced by the supplier and consumer of coal. * * * TREND OF" THERMAL POWER DEVELOPMENT T HE RATE OF ADVANCE in thermal power has been significant during recent years, particularly in the Atlantic Provinces, the Prairie Provinces, Ontario, and British Columbia. While dependence on thermal power in Quebec and the Northern Territories is less than in the remainder of Canada, these regions also eventually will have need for increased amounts of such power.

Jan 1, 1961