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By R. Simkus, J. K. Gowans

Polaris Operations, a Cominco Ltd. lead-zinc mine, is located on Little Cornwallis Island, Northwest Territories, at Latitude 75°23' N and Longitude 96°75' w. When the Polaris Mine went into operation in late 1981, it became the world's most northerly base metal mine.The Polaris Concentrator, housed in a unique process barge, is a basic lead-zinc concentrator where flotation is used to produce the lead and zinc concentrates.The paper describes the ""coarse lead"" flotation feature incorporated in the concentrator flowsheet and describes the start-up problems and continuing operation of this circuit.

Jan 1, 1984

By B. Roy

The Somita plant processes low sulphide gold ore in Burkina Faso with a CIL process. After experiencing recurrent low gold recoveries, Somita undertook an investigation on the source of the problem. COREM conducted a mineralogical study on different pit samples. A series of tests was also conducted on a composite sample from the plant which shows a content of 3.4 g/t in gold and 0.48 % in graphite. A reference test in laboratory resulted in a recovery of gold of 75%, similar to plant recoveries for the evaluated ore. In these tests, even if cyanide is not deficient, it was diverted mainly into iron cyanide complex, copper cyanide complexes and by graphite adsorption. Causes of low recovery were also identified and quantified. Solutions to increase gold recovery were suggested such as increasing gold dissolution kinetics by O2 or by lead nitrate addition, change in activated carbon addition point location to the 1st cyanidation tank and finer grinding to increase liberation. Increase in the pH could also contribute to reduce cyanidation consumption. Following these recommendations, Somita changed carbon addition from tank 2 to tank 1 in the CIL circuit. This change led to an increase of more than 5% in gold recovery. A system for the addition of lead nitrate is also under implementation at the plant and benefit will be evaluated in 2013. Finally, pit management for cyanidation will be done based on mineralogy instead of gold content in the future.

Jan 1, 2014

By J. A. Folinsbee, Andre Robitaille, Tony Y. Chong

"Conventional crushing and grinding is followed by gravity concentration to recover free milling gold. Refractory gold, finely disseminated within the pyrite and arsenopyrite matrix, is recovered by flotation followed by pressure oxidation, cyanidation, and cementation. Non-refractory gold is recovered by cyanidation/CIP processing.A comprehensive test program aimed at improving flotation recovery was initiated in June 1995. Plant testing indicated that flotation tails value could be significantly reduced using mechanical flotation cells. Based on these test results, a flotation circuit that incorporates one of the three existing flotation columns followed by mechanical scavenging and cleaning was developed. Detailed engineering was completed in September 1996. Construction started in February 1997 and was completed in 3 months at a cost of $3.2 million. An on-stream X-ray analyzer was installed to provide real-time arsenic and iron analyses and inferred sulphur value on some of the flotation streams.The new flotation circuit proved to be an instant success. Flotation tails values were reduced by 27%. Final tails solids and solution was reduced from 0.035 to 0 023, and 0.0014 to 0.0006 oz/ton Au, respectively. Based on a mill throughput of 1,620 stpd this decrease in tails value will result in an increased gold production of 7,500 ounces per year. The payback for the project is estimated to be around one year.This paper describes the evolution of the project from bench scale testing to commissioning. Also, the operational and economic impacts on down stream processing are highlighted"

Jan 1, 1998

By Sunil Koppalkar, Liming Huang

"Since late 1980s the research group led by late Professor Andre Robert Laplante at McGill University undertook fundamental studies and applied research of the Knelson Concentrator (KC) and developed a sustainable method to correctly estimate gravity recoverable gold (GRG). In the early time a concept of ‘free gold’ was used, it was defined as the gold that could be separated and recovered from gold ore by amalgamation. Due to health and safety hazards, its practical use had declined. Around 1994, a methodology using a 3-in Knelson Concentrator to measure gravity recoverable gold was established at McGill University. Through more than 10 years’ improvement and optimization, this technique had become a standard method to evaluate GRG for gold ores, gold plant streams and platinum group metals. Until 2006, about 200 GRG tests had been carried out at McGill University for the ores from all over the world. Recently, a modified version of GRG test (short test) with the advantages of reduced processing time and lower cost had been developed for the mundane needs of gold industry.INTRODUCTIONGold gravity recovery has evolved significantly over the past twenty-five years, mainly because of the advent of the Knelson Concentrator (Knelson 1988, 1990, 1992, Laplante 2000). Now, a series of Knelson Concentrators for different applications are manufactured and used in gold industry all over the world (Knelson Concentrators 2004).In 1980s the Knelson Concentrator gained acceptance from mining industry as an effective device for the recovery of gold from grinding circuit. Knelson Concentrator became the obvious choice because of its design features: a relatively long processing time without concentrate discharge (compared to some other centrifuges, such as Falcon Concentrator and Chinese Yunxi Centrifuge at that time), large throughput capacity, treating a wide size range of material, yielding a high grade concentrate with small mass that could easily be smelted. As more and more Knelson Concentrators were accepted in gold industry, mineral processing engineers faced with challenges: what are the separation mechanisms of the Knelson Concentrator? How much gold can be extracted for an ore if a Knelson Concentrator is installed? For answering these questions, a laboratory scale Knelson Concentrator was created."

Jan 1, 2007

By H. Thomasson

This paper will deal with on-site maintenance welding using the stick electrode, electric arc process. It is primarily concerned with the underlying principles, the application of which, or the lack of such application, governs the success or failure of the operation. It will discuss first the base metal or item to be welded, including the field identification of its weld-ability and the determination of the procedures to be followed. Second, it will outline heat effects and the interrelation between heat applied as part of a welding operation and heat deliberately applied as part of a heat treating cycle, stressing the fact that in welding the same basic principles are effective. The third consideration will be weld metal and its control of both composition and properties. Last, but not least, distortion, shrinkage and residual stress will be considered and practical means for minimizing their adverse effects outlined.

Jan 1, 1967

By J. Forster, C. A. Pickles, Mackowiak. K.

The future development of nickel laterite deposits is crucial with regards to satisfying impending nickel demands. The commercial implementation of new hydro/pyrometallurgical processes in recent years has led to significant improvements in the extraction of nickel from the laterite ores. One potential alternative pyrometallurgical processing route would be to selectively reduce the nickel and produce a concentrate with nickel contents similar to those attainable in the conventional flotation of sulphide ores. However, even bench scale studies have not yet been able to produce a high grade (>15% nickel) concentrate from a low grade laterite ore. The present research involved the microwave vacuum reduction roasting of a nickel laterite ore to yield a high grade concentrate, rich in nickel. Firstly, the effects of temperature and pressure on the nickel grade and recovery were investigated using a thermodynamic model. Secondly, briquettes containing a mixture of charcoal and a low grade silicate nickel laterite ore were reacted in a microwave vacuum system. The experimental variables studied were the input microwave energy, pressure and absorbed microwave power. Thirdly, the ferronickel in the reacted briquette was concentrated by magnetic separation and nickel grades of up to 21% could be achieved.

Jan 1, 2015

By Hans von Michaelis

"INTRODUCTIONThe renaissance in gold and silver recovery technology has continued to unfold and it is appropriate to review some of the useful new technologies as well as try to identify some of the industry's future needs and frontiers.The remarkable strengthening in the US dollar has resulted in a relatively low gold price in US Dollars of around $310/oz at the time of writing and silver at $6.25/oz. This general softening in the dollar prices and the recent confusion as to environmental compatibility of cyanidation tailings and effluents, has led to a slowdown in announcements of new operations. Another reason for the slackening off in the USA is that in the past few years a large part of the capital has come from oi I and gas companies that now seem to be losing interest in mineral ventures, and foreign investors for whom the dollar is becoming out of reach. In the author's opinion this represents an unprecedented window of opportunity.Elsewhere in the world where local currencies have weakened, the price of gold is at or close to its all time high.For example, in South African Rands, the gold price was R571.00/oz when the rand was US$1.47 and the gold price reached US$800. Now at US $309/oz and with the Rand at US$0.51 = Rl .00, the local gold price is R600. The price of si Iver in Mexican pesos is not much less than it was when silver reached US$50/oz. Gold, and silver prices in local currencies outside North America are still buovant and at levels where additional investment in new projects is more encouraging.Even in Canada where the dollar is worth about US$0. 75, this provides a smaller but significant cushion compared with US operations. Considering the present strength of the US dollar and even the Canadian dollar relative to many other gold producing countries, there should be significant investment opportunities at today's prices. Mining companies have started to descend on Brazil, for example, where in a matter of just a few years annual gold production has increased from 10 to 70 tons. In South Africa, a Canadian company backed by Swiss financing has been able to take over a Witwatersrand gold mining operation and is installing a huge new tailin9s retreatment plant to process about 1 million tons per month of tailings."

Jan 1, 1985

"Accelerated expansion of Western Canada's metallurgical coal industry has again stimulated considerable exploration activity in the Rocky Mountain Foothills Belt and influenced much of the R&D related to transportation, processing and carbonization. Preparation R&D has included further pilot-plant work on desulphurization, spherical agglomeration and modified compound cyclones (which are also proving themselves in other mineral beneficiation studies). Combustion research, aside from increasingly stressing control of combustion source pollution, has directed special attention to lignite PF firing and problems arising from lignite ash. Studies directed toward the non-fuel utilization of coal have centered on such diverse topics as active carbons, carbonaceous filter media, plant nutrients and industrial applications of humic acid derivatives. In addition, a number of long-range research projects related to such matters as coal chemistry and pyrolysis have been actively pursued, and further attention has been given to improved sampling techniques and analytical methods."

Jan 1, 1969

By Yongbao Zhu

The Ag2O-mediated reactions of cycloaurated compounds with a general formula Au(L)Cl2 (L = bi-dentate C?N ligand) with thiosalicylic acid, N-acetyl cysteine or 1,2-benzenedithiol in DMF proceeds via ligand substitution of the Au?Cl bonds to afford the S-O and S?S adducts all in good yields. The reactivity of the dichloro, S-O and S-S adducts towards thiols were examined by reacting with cysteine in an aqueous medium, revealing that all of Au-Cl, Au-O and Au-N are labile for thiol displacement. The measurement of the inhibitive activities of these compounds against human cathepsins B and K showed that the dichloro and S-O adducts are effective inhibitors with IC50 values ranging from 0.1 to 2.6 -M, and that the S-S adducts are inactive.

Oct 1, 2003

By Michel Doyon

Canadian Context: Exploration ??Space Exploration is within the unique mandate of the Canadian Space Agency ??Global partnerships ??Maintain close relationship with our partners ??New knowledge in S&T ??Retain and attract highly qualified personnel ??Participation in missions leads to design roles in industry and academia ??Collaboration between government laboratories, industry and academia

May 1, 2009

By F. Hassani

This Paper describes a sudden spill of rock waste used for backfilling from a waste pass at one of the underground mine in Canada thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in future. The investigators from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied and appropriate measurements were taken and samples of the waste material was collected for further test and analysis. The field visit and the interview of the witnesses allowed a detail documentation of the events. The sequences of events related to the incident together with the experimental results obtained in the course of the investigation is detailed. The waste material was characterised in the laboratory with regard to its behaviour in the presence of water. This information is then discussed and the failure mechanism involved in this accident is identified. The full recommendation as well as the immediate operational measures implemented by the mine to prevent future occurrence of such events are discussed and presented.

May 1, 2003

By G. J. S. Govett

World mineral production is dominated by six countries - the U.S., the U.S.S.R , Canada, South Africa, Australia and China - which also hold most of the reserves of the world?s minerals. For the developed and centrally planned countries, there is a strong positive correlation between the mineral production of a country and its land area: there is no correlation between mineral production and land area for the less developed countries. These facts imply that, after taking due account of geological controlling factors, a country may expect to produce minerals in approximate proportion to its land are a provided that political, economic, and historical factors are conducive to mineral exploration and mining. Contrary to popular political belief in many parts of the world, the developed countries are the major source of mineral imports for the industrialized countries. Moreover, exports of ores and minerals account for a relatively small par t of world trade, and are an important factor in the export picture of only a few of the less-developed countries. The looming resource confrontation between the developed and the less-developed countries is based largely on the false premise that the industrialized countries of the world are minerals-poor and owe their wealth to cheap minerals from the less-developed countries. The data presented refute this. Geological controls are relatively minor in the present distribution of world mineral production; political and economic factors are dominant. It is argued that an expansion of world trade in minerals - based on increased exploration and new forms of finance for mining ventures - rather than cartels, price-fixing and trade restrictions is by far the preferable solution to the problem of redressing the legitimate grievances of the poor countries of the world.

Jan 1, 1977

By P. H. Tolcher

Canada, as the Free World's largest mine producer of zinc and the third largest mine producer of lead, has a vital interest in the future growth in demand for these metals. This paper traces the development of lead and zinc consumption in the last two decades, both on a total-Free-World basis and by major market areas. How Canada, as a major mine producer, has shared in this growth is also indicated. In addition, future consumption for both metals in the current decade of the 1970's is fore-cast. The demand these projections will make on Free World mines, particularly on Canadian mines, is examined. Some of the opportunities and challenges the Canadian mining industry will likely face during this period are also dealt with.

Jan 1, 1971

By Larry J. Hulbert, Louis J. Cabri, John L. Campbell, Gilles Laflamme, Chris G. Ryan, Soey H. Sie, Rolando Lastra

"Abstract- The mineralogy of samples from the Wellgreen Cu-Ni-Pt-Pd deposit, Yukon Territory, is complex and the metals of interest are contained within fme-grained minerais which vary in size and mineral associations from sample to sample.The major Ni carriers are pentlandite and violarite; the major Cu carrier is chalcopyrite. About 700Jo of the major Ni carriers and 78% of the major Cu qmier will be liberated at a grind of 80% -'}f,.7 J.Uil (-500 mesh) for typical low-grade gabbro (West zone, sample No. 1). For typical ""clinopyroxenite"" (West zone, sample No. 2) and typical ""clinopyroxene-rich peridotite"" (East zone, sample No. 3) the liberation would be 71""lo and 65% for Ni, 74% and 60% for Cu, respectively. Fine grinding, however, cannot liberate the Ni contained in silicates and pyrrhotite, estimated to total24.5% for typicallow-grade gabbro (West zone, sample No. 1), 15% for typical ""clinopyroxenite"" (West zone, sample No. 2), and 12% for typical ""clinopyroxene-rich peridotite"" (East zone, sample No. 3).The principal Pt carrier (sperrylite) varies considerably in grain-size between samples and fme grinding, required to liberate the major Ni and Cu carriers, may be counterproductive in samples where sperrylite is relatively coarse-grained, as sorne would then be unrecovered (e.g. sample No. 1). In addition, sperrylite in samples No. 2 and No. 3 is closely associated with magnetite.Palladium occurs in diverse ways. It occurs in the form of several Pd minerais (e.g. sudburyite, testibiopalladite, merenskyite), as a replacement for Ni in several tellurides, antimonides and tel­ lurantimonides (e.g. melonite), or as very low concentrations in pentlandite (up to 34 ppm), chal­ copyrite (up to 9 ppm), and pyrrhotite (up to 5.6 ppm). Palladium minerais and Pd-bearing minerals are strongly associated with chalcopyrite in sample No. 1 and will thus report to a Cu concentrate. However, 22% of the total Pd is in solid solution in pentlandite in this sample and will thus report to the Ni concentrate. In samples No. 2 and No. 3, less Pd occurs in solid solution in pentlandite, and the PGM are distributed mainly among pentlandite, chalcopyrite, and magnetite in sample No. 2, and among pentlandite, pyrrhotite, chalcopyrite, and magnetite in sample No. 3. Therefore, the feasibility of magnetic concentration should be investigated for samples like No. 2 and No. 3, in order to improve Pt and Pd recoveries.Rhodium was found to occur as rare hollingworthite, in sparse cobaltite (up to 2.7%) and, as low concentrations in chalcopyrite (to 10 ppm) and pentlandite (to 12 ppm) by proton microprobe. Iridium occurs in hollingworthite (up to 7.8%) and very rarely as the native metal or in an undefmed Re-Ir-Os-Ru alloy. Ruthenium was determined by proton microprobe analyses to occur in pentlandite (up to 13 ppm) and chalcopyrite (up to 10 ppm), in addition to rare laurite and Re alloy."

Jan 1, 1993

By W. Noel O?Brien

Introduction Since 1930 numerous improvements have been made in equipment designed for the mechanical removal of broken ore in underground mining operations. New applications of mechanical equipment, as? well as improvements and adaptations of well established systems, are being made continually. It is the purpose of this paper to discuss present-day equipment for the removal or transfer of broken ore by means of a powered hoist and scraper arrangement. The terms used throughout the paper are those commonly employed in the trade literature and by mining men. The terms slusher hoist, hoist, and scraper hoist are used inter-changeably to mean a machine, powered by compressed air or electricity, with drums for the winding of wire rope. The tail rope, also known as the pull-back rope or return rope, drags the empty scraper toward the tail-sheave, that is, back to the loading point. No attempt is made to cover the entire field of application of scraping methods. Rather it is the? writer's desire to emphasize the fundamental principles of scraping practice and design and to relate them to some modern applications. The available literature on scraping practice has been freely used. together with personal observation and information and advice of practising engineers and representatives of companies manufacturing slushing equipment.

Jan 1, 1951

By Jack Young

U. S. Steel Canada Inc.’s Lake Erie Works is the last green field integrated plant to be built in North America. The plant was designed using the best available environmental technology to develop an environmentally friendly production facility. A summary of the technology and measures used in the construction of the plant are summarized in this paper.

Jan 1, 2015

By Mike Dry, Mani Manimaran, Mykolas Gladkovas, Mariam Melashvili, Chris Fleming

Development of a new hydrometallurgical flowsheet requires quantitative description and optimisation of all chemical processes in each step in the process, as well as mass and energy balances across a fully integrated circuit incorporating all the unit operations. This paper covers steps leading to early modelling of a gold processing plant based on a bromine/bromide lixiviant. Research conducted at SGS Lakefield in collaboration with Albemarle provided the data that were used in the development of this model. A previous investigation in this series described the leaching behaviour of various mineral types in Stabilized Bromine reagent. This paper is concerned with the gold recovery operations associated with a conceptual bromine leaching process. The recovery of gold by different types of resin and activated carbon was studied, along with various methods of stripping the gold from the extractant. The circuit is closed by electrolysing the spent leach liquor to oxidize some of the contained bromide back to bromine that would allow recycling the regenerated leach solution back to the leach step in the process.

Jan 1, 2015

By John Frostiak, Lloyd Buckingham, Kenneth G. Thomas, Luis Wilson

"The El Indio roasting facility associated with El Indio Mine in Central Chile has operated since 1981. It is a facility developed to remove arsenic and antimony from gold bearing enargite/pyrite flotation concentrates.The three installed roasters are Nichols Herreschoff units each with 14 hearths and measuring 4.85 metres diameter. Hearths are rabbled by central shaft driven rabble arms. Product is progressively heated to 750°C under neutral to reducing atmospheric conditions to drive off labile sulphur, arsenic and antimony.Ancillary equipment includes skip hoist feed arrangements, water cooled screw conveyors for transporting and cooling calcine, gas cyclones, post combustion chambers, heat exchangers, electrostatic precipitators, bag houses, gas scrubbers and packaging facilities .Operating practices, history, mineralogy and results are reviewed. The improvements to arsenic and antimony extraction, ambiental conditions and environmental achievements are discussed.INTRODUCTIONHistoryThe El Indio property lies in the El Indio belt, a copper, gold and silver area approximately 175 km long by 10 km wide. The property is located in the Andes Mountains of the central part of Chile at latitude 30"" South and 160 km from the sea-side city of La Serena. Plant location is at 3850 meters above sea level.The property currently consists of two underground mines feeding the El Indio plant and an open pit feeding the newer Tambo leach plant. The property has been controlled by a succession of owners (St. Joe Minerals, Fluor, Bond Gold International and Lac Minerals Ltd.) before acquisition by Barrick Gold Corporation in 1994."

Jan 1, 1999

By J. E. Gill

"The name 'Canadian Shield' is used for a vast area; largely in northeastern; Canada; underlain by Precambrian rocks. The part in Canada has an area; of about 1; 790; 000 square miles. Extensions in Greenland; Labrador; Newfoundland; and the United States bring the total area to around 2; 800; 000; square miles. The boundaries of the Canadian part are shown in Fig. 1.; At its margins; the Precambrian rocks can be seen at many places to; extend beneath a cover of flat-lying Palxozoic or later sediments. Information; from borings in the Plains and natural exposures in mountain-built belts; show that similar rocks form a large part of the continental platform. The; Shield; therefore; is a large exposure of what may be regarded as the foundation; of the continent."

Jan 1, 1954

By 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. With the development and growing use of DEM charge motion simulators for mill optimisation and design, it is possible to describe the fundamentals of grinding mill behaviour, in improving the understanding of internal grinding mill dynamics and in developing solutions to industrial practice. The main challenge to bringing this DEM technology to the mill operator however was the need for substantial computing power and time. However, what about a simplified DEM charge motion model running in real-time? What about the use of sensor technologies to correct any possible drift in simulator prediction? Could such a technological system be used to predict mill performance and eventually be used for mill control and optimisation? Some of these questions are answered with the development of an "on-line" DEM charge motion simulator package (SAGTools?) along with that of a number of sensor technologies (liner wear, acoustic, instrumented ball) that can contribute to simulator precision. With the objective of bringing this modelling and sensor technology into the concentrator control room to assist operators, this paper aims to describe the main elements of this emerging and developing technology and discuss how it can lead to online mill performance prediction and eventual control.

Jan 1, 2007