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By D. Vanin

"Conventional single heading track drifting in the hard rock mining industry has not shown any significant improvements in advance rates, despite the advent of modern track jumbos and igh speed muck handling systems .This paper presents Kiena 's experience in using a 7 ft 2 in. diameter larva Mark 6 Tunnel-Boring Machine (TBM) for driving 6000ft of drift.IntroductionKiena Gold Mines is located about 5 miles west of the town of Val d'Or, Quebec, approximately 300 miles north of Montreal. The mine commenced production in October 1981 and has gone through various expansions of ore production with 287 916 metric tonnes in 1982 to reach 453 800 metric tonnes in 1986.Due to the majority of claims being covered by a lake, a grassroots exploration drive of remote areas of the property was required to allow diamond drilling on a yearly basis. High speed sequential excavation methods (SEM) of single heading drifting in the mining industry has not progressed much in the past 20 years despite the advent of electric-hydraulic jumbos, Haggloader and Hagglund type cars. Certain examples of record SEM drifting advances have been performed in the past but only under very specific ground and cost conditions."

Jan 1, 1987

By J. Janeson

Wall control at the Pipe Open Pit is of primary importance in ensuring the long-term stability of the operation, while keeping costs to a minimum. Blasting techniques have been adapted to the variations in competence and structure of the wall rocks. A portion of the perimeter wall is being developed in incompetent peridotite . A recent change in pit slope design provides a wide safety berm on alternate benches. A support program which consists of pinning the crests of wide berms with vertical reinforced concrete dowels and horizontal bolting of walls shows evidence of increasing the stability of the pit walls. This paper describes the blasting and support techniques which are contributing to successful wall control in the Pipe operation.

Jan 1, 1979

By K. Schimann, H. D. Knipping, J. P. Fouques

"RESUMELe gisement d 'uranium de Cigar Lake, dans la région de l'Athabasca au nord du Saskatchewan, fut découvert en mai 1981 par Cogema Canada Ltée, opérant pour Ie compte de la ""Waterbury Lake Joint Venture"".Le corps minéralisé. qui est dépourvu de toute expression directe en surface, est situé a la discordance entre les met sédiments du wottaston Group (Protérozoïque inférieur ou Aphébien) et les grès de l 'Athabasca (Protérozoïque moyen ou Hélikien), à une profondeur de 410 a450 m.Fin 1984, Ie gisement était reconnu par 105 sondages minéralisés repartis sur une longueur de 1800 m, pour une largeur comprise entre 25 et 105 m. 11 se présente sous forme d’une lentille aplatie de 5 a30 m de puissance, et montre une remarquable continuité d'ensemble. Une ride ou bombement topographique de la discordance est associée au gisement surtoute sa longueur.A l'échelle régionale, le corps minéralisé à est associe à un corridor structural d’orientation est-ouest, a l'intérieur duquel des facies particuliers aténdance blast mylonitique sont développes dans les formations métapolitiques agraphite du socle métamorphique. Il est entouré par un halo d'altération très important, caractériser Ie développement de minéraux argileux alumino-magnesiens (illite-chlorite).La minéralisation est située, pour la plus grande part, dans les grès d'Athabasca, et se compose essentiellement d'uraninite et de sulfo-arseniures de nickel et de cobalt,De nombreux levés géochimiques et géophysiques ont été effectues dans la région de Cigar Lake. Aucune anomalie ne peut être associée directement au corps minéralise, mais la combinaison des données en provenance de plusieurs sources s’est révélée fort utile au niveau de l’interprétation géologique régionale et de la définition des cibles de sondages a l'intérieur des zones reconnues favorables.Le gisement de Cigar Lake présente de nombreuses analogies avec plusieurs des gites classiques de la région de l'Athabasca; il est caractérise en particulier par l'intensité des phénomènes d’altération et la présence de minéralisations extrêmementriches.En 1984, les réserves géologiques globales estimées par géostatistique sur I ‘amas minéralise principal s 'élevaient a 110 000 tonnes d'uranium, aune teneur moyenne de 12.2%, avec une précision de 25% à l'intervalle de confiance de 95%.ABSTRACTThe Cigar Lake uranium deposit, in the Athabasca area of North Saskatchewan, was discovered in May 1981 by Cogema Canada LId., as operator of the Waterbury Lake Joint Venture. The deposit, which is devoid of direct surface expression, is located at the unconformity between the Lower Proterozoic (Aphebian) Wollaston Group meta-sediments and the Middle Proterozoic (Helikian) Athabasca sands tone, at a depth of 410 m to 450 m below surf ace.AI the end of 1984, the deposit had been defined by 105 mineralized holes over a length of 1800 m and a width of between 25 m and 105 m. It has the shape of a flat-lying lens 5 m to 30 m thick and shows a remarkable longitudinal and latera continuity from the information obtained to date. A well-defined bulge of the unconformity underlies the mineralized zone over its entire length.The deposit appears to be controlled by an east-west-trending structure within which a particular rock facies (""augen gneiss"") has developed in the graphitic metapelites of the Wollaston Group. It is surrounded by a strong alteration halo affecting both sandstone and basement, characterized by extensive development of Mg-A I rich clay minerals (illite-chlorite).The mineralization is hosted principally by the Athabasca sandstone, and consists mainly of uraninite and sulfo-arsenides of nickel and cobalt.Numerous geochemical and geophysical surveys have been carried out in the Cigar Lake area, and no specific geochemical or geophysical anomaly can be directly associated with the mineralized body, although there may be locally a good coincidence. However, a combination of several methods proved extre"

Jan 1, 1986

By G. E. Agar, W. B. Kipkie, R. A. Tenbergen

"This paper describes the successful pilot plant testing of a flowsheet, developed at Inca Ltd.&apos;s J. Roy Gordon Research Laboratory (JRGRL), for improved separation of the constituent minerals in a bulk copper-nickel concentrate.The flowsheet utilized the fact that xanthate concentration on the mineral surfaces is the most important variable affecting the high lime separation and that reduction of the xanthate concentration could be affected by an oxidative conditioning stage.When the adsorbed xanthate was reduced to a suitably low level, chalcopyrite and pyrrhotite could be floated to leave a high-grade nickel concentrate as the residue. Sodium cyanide was added to the froth product 10 depress pyrrhotite and any remaining pentlandite. The temporary depression of chalcopyrite by the sodium cyanide was overcome by introducing a conditioning step following cyanide addition . The advantages of the flowsheet; improved copper-nickel separation, operation without heating of the pulp, production of both high-grade nickel concentrate (29.5% Ni, .26% Cu) and copper concentrate (<0.5% Ni, 30% Cu) were all realized.IntroductionLaboratory test work undertaken at Inco and described previously(1) has demonstrated the importance of low xanthate concentrations on the mineral surfaces in the copper-nickel separation at the Copper Cliff mill.It was determined that oxidation of the separator feed (a cleaned bulk concentrate, grading about 11% Cu and 11% Ni) to lower the xanthate concentration on the mineral surfaces prior to separation significantly improved the quality of the separation (CI 4)*, particularly when no cyanide is used, but also when cyanide is added. As well, it was found that the oxidation permitted a pentlandite-pyrrhotite separation - the oxidation step brought about a decrease in the flotation-rate of pentlandite leaving pyrrhotite and chalcopyrite largely unaffected. Consequently, it was possible to produce a highgrade pentlandite product (30% Ni, 0.3% Cu) at ~83% Ni recovery , as well as a high-grade copper concentrate (0.5% Ni, 30% Cu at -96% Cu recovery)."

Jan 1, 1985

By L. Vu, V. Popov, J. Beland, R. Darling

"The Ferderber gold deposit is of Archean age. It consists of a series of gold-bearing quartz lenses within a shear zone that crosscuts the central part of the quartz dioritic Bourlamaque batholith. On average, this zone strikes N70E and dips 65SE. The Ferderber shear zone, which hosts the ore lenses, has been affected by a succession of tectonic events. A possible early period of brittle shear, accompanied by the formation of quartz lenses, resulted from strike slip movement along the zone. These early quartz veins were subsequently folded and boudinaged during reverse movement that accompanied a prolonged period of ductile shear. More quartz veins were emplaced in the shear zone at this time; these were also deformed by the thrusting. The latest tectonic event to affect the shear zone was a period of brittle fracture.Early dextral strike-slip movement on the shear zone is suggested by the local occurrence of Riedel shears, the preferred association of ore with east-northeast oriented segments of the zone, and by the apparent en echelon arrangement of some ore lenses. The most important event, a reverse movement, is indicatedby the attitudesoffoliation, folds, boudins, COS tectonites and slip planes. The late brittle fracturing formed narrow gouge filled faults, locally flanked by brecciazones, whichrun generally within and parallel to the shear zone, and also conjugate fractures that crosscut the zone.The Ferderber and six other adjacent gold deposits were formed in a structural regime dominated by a generally horizontal north-south regional compression. The Y axis of the strain ellipsoid is east-west and varies from horizontal to a plunge of 25 0 w."

Jan 1, 1987

By V. Gaudreault

Rio Tinto Alcan (RTA) has three smelters that use the Alcoa P155 technology: two in Canada (Grande-Baie and Laterrière, Saguenay, QC) and one in the United States (Sebree, Kentucky). The oldest RTA P155 smelter was built in the 1970s (Sebree) and had an initial current intensity of 155 kA. In the 1990s, RTA installed an amperage booster in Grande-Baie smelter to increase cell productivity. Since then, RTA has continuously pushed the limit of this technology and the target amperage that was 195 kA in 2005 has been increased to 210 kA in 2010.This article describes the successful plant-scale trials to increase current intensity from 195 kA to 210 kA, and the key performance indicator results. It demonstrates RTA&apos;s technology leadership to undertake such a development with its Brownfield smelters.

Jan 1, 2011

By J. E. Udd, S. Bharti

"ABSTRACTMonitoring of stability conditions in underground mines permits management to assess the response of the rock mass to mining strategies. Monitoring of movements, if sufficiently early, may also permit operators either to avert potential failures or to develop alternative approaches to extraction.The Falconbridge organization has been a leader both in the uses of rock mass stability monitoring techniques and in the development of instrumentation.In this paper, the authors review the Falconbridge approaches to monitoring, and present case history examples to illustrate the application of the various instruments used.RESUMELa surveillance des conditions de stabilité dans les mines souter-raines permet aux chefs d&apos;enterprises d&apos;évaluer les réactions de la masse rocheuse aux méthodes d&apos;extraction minière. Si le contrôle des mouvements du terrain est effectué assez tot, l&apos;exploitant pourra prendre les mesures qui s&apos;imposent, soit pour éviter les détériorations possibles ou pour mettre au point de nouvelles méthodes d&apos;extraction.Le groupe de la Falconbridge a ére le premier a utiliser des techniques de vérification des conditions de stabilité de la masse rocheuse et a mettre au point l&apos;appareillage requis.Ce document présente une revue des méthodes employées par la Falconbridge pour assurer la surveillance active de la stabilité de la masse rocheuse et illustre au moyen de cas concrets la manière d&apos;utiliser les divers appareils."

Jan 1, 1987

By Michael L. Wayman

Native copper is copper which exists in nature in elemental, metallic form, rather than being chemically combined as is the case with the more usual oxides, sulphides, carbonates, etc. Several other metals, including gold, silver and platinum also occur in native form as do, rarely, iron, lead and mercury; a few naturally occurring native metal alloys, notably electrum (gold-silver) and tumbaga {gold-copper or gold-silver-copper) are also known. An analysis of the relative availabilities of native metals as nuggets in a useful size range111 shows native copper to be by far the most abundant of the native metals, exceeding both gold and silver by at least two orders of magnitude. While such an estimate is crude, it serves to illustrate why copper was one of the first metals to have been used by ancient peoples. Native copper is known to occur on all inhabited continents, although its exact occurrence and abundance in ancient times cannot be unambiguously determined because many surface deposits may have been totally exploited and are therefore no longer identifiable. It is clear, however, that native copper does or did occur in all areas inhabited by the early metal-using cultures, for example in the Andes, in Central America and in the Near East. It is remarkable that most of the world&apos;s native copper occurs in the deposits of the Lake Superior region, primarily on the Keweenaw Peninsula of northern Michigan and on Isle Royale, an island in Lake Superior some 50 miles north of the Keweenaw deposits. Canadian deposits of native copper are found in Newfoundland and Labrador, Nova Scotia, Quebec, Ontario, British Columbia, the Yukon and the Northwest Territories (on Victoria Island, Bathurst Inlet and the Coppermine River area). It was to locate the latter deposits that the explorer Samuel Hearne was sent overland from Hudson&apos;s Bay in 1770; they were also surveyed by Sir John Franklin&apos;s expeditions in the 1820s.

Jan 1, 1999

By A. Ignatow

"A review is made of some of the principal factors and conditions that are, and will be, important to the over-all market climate for asbestos fibre and for the future of Canada&apos;s asbestos industry: - health hazard associated with asbestos exposure;- uncertain international regulatory environment for continued asbestos use;- adverse public reaction to asbestos;- product liability/litigation costs (U.S.A. primarily);- promotion of substitution by governments and asbestos user industries; and- minimal product and market development efforts by asbestos producing and consuming industries.In addition, Canadian producers, who export some 95 per cent of their production, face additional constraints:- dramatically reduced integration with asbestos-consuming industries;- 60 per cent of exports to most rapidly declining markets (U.S.A., Europe);- increased competition from offshore producers favourably located to growth markets in developing countries;- increasing production costs;- a strong dollar;- disadvantageous freight rates; and- loss of price leadership and price erosion.Future market trends, as well as prospects for Canada&apos;s asbestos industry, will be projected in this paper.Economic FactorsTable 1 presents asbestos fibre production in all countries for the period 1980-82. In certain instances, e.g. U.S.S.R. and China, these are capacity estimates as production statistics are not officially published. The U.S.S.R, by far, is the world&apos;s largest producer accounting for some 50 per cent of world production, though most production is consumed internally or by COMECON countries. It is estimated that some 700 plants produce asbestos-containing products within the U.S.S.R.Canada accounts for some 25 per cent of world production though it ranks first in world trade. Other important producers are South Africa Zimbabwe, Brazil and Italy. Since 1979, Canada&apos;s asbestos mining industry has experienced a dramatic drop in production and exports of asbestos fibre, as demonstrated in Table 2."

Jan 1, 1985

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By H. Vermette, J. Demers, R. Leclerc, P. Bergeron, P. Hudon, A. Lessard

The Arvida Smelter marked its 80th anniversary in 2006. Arvida currently operates 6 potrooms equipped with prebaked side-feeding pots producing 160 000t of aluminum per year, requiring the supply of 300 000t of alumina per year. In the past, to ensure reliable alumina supplies to the pots, especially in winter, a safety stock of alumina was kept inside the plant. The improved reliability of shipping on the Saguenay River has cut the need for such a stock. However, the stoppage of 8 Soderbergtechnology potrooms, starting in the 1980s up to 2003, generated alumina from the cleaning of pot pits, totaling 18000t and leading to the building-up of a significant alumina stock again. Concerns over working conditions, effect on potroom operations, and dust emissions prevented Arvida from tackling effectively this impressive alumina stock. Yet the increasing cost of alumina has created a strong motivation to use the stored alumina. In 2004 Arvida launched a project to recycle the stored alumina. This 4-year project aimed at clearing the alumina stock without affecting the operation of the smelter. It involved changing work organization, improving equipment and controlling the effect of the recycled alumina on the smelting process and working conditions.

Jan 1, 2006

By M. H. Allan

"This paper presents the geographic and geological setting of Saskatchewan Power Corporation&apos;s Poplar River Mine in south-central Saskatchewan, about 8 miles from the U.S. border. Generally the mine, which is being expanded to four million tons per year, is in an extremely disturbed geological area with severe dewatering problems. The lignite coal, which is strip mined, is supplied directly to an electric power generating station by means of a 7-mile unit-train private railroad.A number of unique reclamation and socio-economic problems were encountered because of the proximity to the U.S. border and because of the lack of experience of the regulatory authorities in projects of this kind. These are described in some detail, as well as the performance of one of the largest draglines in Canada. IntroductionThe Saskatchewan Power Corporation is a publicly owned utility which has the franchise to supply electricity and natural gas to all customers within the boundaries of Saskatchewan.Saskatchewan is a province which can almost be divided in two: the populated southern portion, principally devoted to farming, and the northern portion which is mostly on the Precambrian Shield and consists of lakes, rocks and muskeg. This portion is largely uninhabited except for a number of small villages. However, in the last few years there has been considerable mineral exploration and development, notably for uranium. This has helped considerably in the diversification of the basic agricultural economy of the province.Saskatchewan consists of 251,700 square miles, 761 miles north to south and an average of 335 miles east to west. It has a population of approximately 960,000, giving a population density of four persons per square mile. The Saskatchewan Power Corporation supplies 357,249 electrical arid 221,378 natural gas customers."

Jan 1, 1982

By Robert Strachanm

The East Kootenay coal-field, situated close to the boundary between the provinces of Alberta and British Columbia, is composed of four small areas locally called the Crow&apos;s Nest Pass, the Upper Elk, the Flathead and Crown Mountain, and comprises an area of about 3 78 square miles. From eleven to twenty-five seams have been exposed of two feet and over in thickness, with a total thickness of about 200 feet of coal, and reckoning about one hundred feet to be workable, gives an estimate of coal available of about thirty-seven billion tons. The coal is a high-grade bituminous, occasionally tending towards anthracite, and the majority of the seams furnish a. very good quality of coking coal as well as an excellent steam coal. The coal-field is found in the mountain ranges in long narrow strips. The age of the fonnation and the thickness of the covering beds have had considerable influence on the character of the coal, and lateral pressure and disturbances in the process of mountain-building have wrought great changes. With such an abundance of coal, it has been a disappointment that the East Kootenay field has not figured larger industrially. So far only one portion of the coal-field has been utilized. This is the Crow&apos;s Nest, where, in 1898, the Crow&apos;s Nest Pass Coal Company commenced development. Access to the coal seams was easily obtained, the mountain creeks having eroded away the covering, and mines were driven into the coal seams. In that year about ten thousand tons of coal were produced from the mine at Coal Creek.

Jan 1, 1924

By Gaston Gingras

"IntroductionL&apos;entretien de l&apos;equipement minier dans les mines à ciel ouvert est une activité qui est aussi vieille que I&apos;existence des mines et qui a progressé au cours des années pour suivre l&apos;évolution des techniques d&apos;exploitation. Lors de la mise en usage de s premières pelles à la va peur, celles-ci étaient généralement entretenues par I ‘équipe de quatre hommes qui était responsable de son opération. Pour les travaux plus compliqués ils utilisaient les services de machinistes qui eux savaient comment réparer Ie moteur à vapeur et couler des coussinets de ""babbit"". Les premières pelles diesel étaient entretenues de la même façon mais pour les réparations au moteur, on devait recourir au représentant du manufacturier qui était Ie seul à avoir les compétences nécessaires.Ce n&apos;est vraiment qu ‘après la deuxième guerre mondiale que I ‘usage de l&apos;équipement mobile s&apos;est répandu dans les mines à ciel ouvert pour débuter les extractions selon les méthodes que I&apos;on connaît aujourd&apos;hui.L&apos;entretien de l&apos;équipement minier de façon organisée à débute avec I ‘usage de ces machines dans nos mines. Ces machines étaient un peu primitives, petites et pas très dispendieuses a I&apos;achat. Même si la disponibilité était basse, elles fournissaient quand même un rendement qui en ces temps était acceptable. L’organisation de I ‘entretien de cet équipèrent était assez primitif et n&apos;occupait qu&apos;une place secondaire aux yeux de la direction de la mine."

Jan 1, 1988

By A. Kowalski

Telvis Limited, manufacturer of an emergency communication dispatcher&apos;s broadcasting system, now introduces the possibility of a remote software upgrade to its devices. The paper presents methods, features and ways to accomplish this task. It describes the mechanisms used and the opportunities that arise from the use of this type of functionality. The mechanism software update presented applies to devices on the surface and in underground areas of mines. The electronics used currently allow the use of remote software updates, but the mining equipment makes little use of these methods. This paper aims to start the discussion on this topic and tries to lay the path of development by showing one of the first examples of the application.

Aug 1, 2013

By P. R. Clark, M. D. Gleghorn

"IntroductionAt TransAlta Utilities Corporation&apos;s Highvale Mine, located west of Edmonton, Alberta (Fig. I and 2), dragline stripping has proved to be a practical and economical method of overburden removal and future plans have been based upon the continued use of draglines (Fig. 3) as the major stripping equipment (Williams, 1979, Nikols et al., 1986). However, long range planning has shown that the capacity of draglines alone will be exceeded in the early 1990s as mining progresses into deeper overburden cover (Tapics, 1983). Strip ratios will increase from I.3 bank m!/ t of coal in 1985to 4.5 bank m3 / t in 1995. During this period the depth of overburden will increase substantially and the areas to be mined will be characterized by weak soils including glacially displaced overburden. This increased overburden depth in relatively weak soils will make it impractical to _continue side casting by draglines without prestripping in advance. In 1983, a major investigation was initiated to determine what additional overburden removal equipment was appropriate to the Highvale operations, and recognizing the long delivery times of this major equipment. when it would be required. This paper describes studies and tests which were undertaken in 1983 and 1984 to select prestripping methods and equipment for the future operation of the mine.Previous planning studies have shown that with the current burn schedule and with the economies of progressing from low cover to high cover, as has been practiced in the past, overburden volumes will exceed the capacity of the existing draglines in the early 1990s (Fig. 4). These previous studies had placed reliance on (I tandem dragline operation for future overburden removal requirements up to a depth of 45 m throughout the Highvale Mine. New drilling together with the associated geotechnical studies and some detailed planning on the practicality of using tandem draglines, created concerns about their universal application. Even without considering geotechnical conditions there was a depth limitation to tandem dragJines and substantial prestripping would be required to achieve the ultimate depths."

Jan 1, 1987

By Joanna LaForte

"IntroductionIn respect to The Human Dimension by M. Phyllis Bray, this author&apos;s impression is that research on long distance commuting (LDC) is long overdue. This type of mining is not new to many workers, especially those from areas such as the Maritimes, who have had to look for work away from their families for at least a decade. Perhaps to the industry the over-all set-up is new, but to workers who have faced mine shut-downs in their areas finding a job was the main objective and if the security of long-term employment was evident, then the families might join them later. This was the situation with which the writer&apos; s family was faced.LDC LifestyleBeing the wife of an underground miner, the author has personally experienced this lifestyle for almost 10 years, and has never experienced accommodation in a company town. The first five years of marriage were spent in a small rural municipality within 50 miles of the worksite, but the town had industry separate from mining and was not affected by the mine shut-down.Since her LDC lifestyle began her family has been pretty much city-based, out-of-province commuters with two children and a third to arrive some years later. She therefore lived a fairly normal married life with a husband home daily. The author has experienced life with a husband who worked away for five-day stretches and then drove long distances to be home weekends or the portion of time left over from driving and fatigue. She has done the 3D-days in/l4-days out routine, and for approximately the past four years has been existing on a two-weeks in/two-weeks out ritual .The author does not agree that the ""bottom line is that mining families go where the jobs are"" . The miners go where the jobs are and the families fend for themselves with the assistance of the pay cheque making it home each pay period.Perhaps because there are many personal frustrations with this type of lifestyle, perceptions may be inaccurate. Having only dealt with underground operations, there may be gross differences between the pressures and demands of other forms of mining."

Jan 1, 1991

By P. D. Kondos, J. R. Goode

Given the global inventory of low grade and refractory gold deposits, processes that could turn these challenged deposits into mines are of considerable interest. Such gold deposits have low value and potentially high operating costs and so they pose special challenges for the mining engineer and metallurgist. Conventionally, refractory gold ores have been processed by whole ore pressure oxidation and roasting, or flotation followed by roasting, pressure oxidation or bio-oxidation of the concentrate. Halide-based processes have recently been developed that might be applied to concentrates. Low grade refractory gold ores have been processed using heap bio-oxidation followed by cyanide heap leaching or milling. Other processes are emerging. Barrick has completed an inventory of emerging technologies (1). A summary of the current status of these developments will be presented with the view that, with additional development, some of these technologies or a combination thereof may unlock the value of these deposits.

Jan 1, 2005

By Jacek Paraszczak

L?exploitation rentable des gisements de type filonien constitue un problème important dans le contexte actuel de l?industrie minière québécoise. Les études effectuées depuis 1994 ont indiqué, que la technologie d?abattage mécanique utilisant l?outil hydraulique appelé « éclateur radial-axial » constitue une alternative intéressante par rapport aux méthodes conventionnelles par le forage et sautage. Les essais du prototype de l?éclateur ont prouvé qu?il est en mesure d?abattre les roches dures dans un environnement minier, mais sa performance dans les termes de masse du roc abattu dans une unité de temps a soulevé certaines doutes. Pour cette raison, une étude de préfaisabilité de l?éclatage en tant qu?une technologie d?excavation souterraine a été réalisée. Cet article présente quelques résultats des travaux effectués dans le cadre du contrat octroyé à l?Université Laval par le Ministère des ressources naturelles du Québec. Leur objectif principal consistait à comparer, pour les conditions des gisements filoniens, la productivité et les coûts des méthodes d?exploitation souterraine utilisant l?éclatage par rapport à celles conventionnelles. Deux variantes proposées de cette méthode ont été comparées avec la méthode conventionnelle sur le plan du coût (par tonne de minerai) et de la teneur de coupure de minerai d&apos;or. Les études ont démontré que l?application de l?éclatage représente un potentiel de réduire ce coût, surtout dans les situations où l?abattage sélectif pourrait avoir lieu. Pour le cas de base on a trouvé, qu?il serait possible de réduire la teneur de coupure par la marge d?environ 16 ? 26%. Toutefois, les études de sensibilité ont démontré, que le coût dépend de façon important de la productivité d?éclatage, qui, pour sa part, varie beaucoup en fonction de paramètres du massif rocheux devant être abattu.

Oct 1, 2001

By M. Mirnezami, J. A. Finch

The McGill component of the consortium contributed detailed examination of the electrokinetic properties of the constituent minerals, primarily pentlandite and serpentine. Mineral specimens were derived from an ore sample; mineralogical examination showed the serpentine was predominantly clinochrysotile, a fibrous mineral responsible for much of the flotation separation problem. The study included design of a novel sedimentation potential measuring device to classify the surface charge of the ore and electrophoresis measurements on single and mixed minerals which progressively approached flotation conditions. The sedimentation potential measurements provided a general association between surface charge and the visual state of aggregation as a function of pH. The electrophoresis experiments started with single minerals in a background of indifferent electrolyte and progressed to mixed minerals in a background of supernatant derived from an ore sample. The single mineral tests supported the suspected electrostatic interaction, i.e., hetero-coagulation, at flotation pH 9-10. The mixed mineral tests demonstrated this interaction and also revealed hetero-coagulation with Mg(OH)2 precipitates, derived from the supernatant. This interpretation was confirmed by optical and electron beam imaging. A series of agents, CMC, polyphosphate, soda ash, EDTA, were examined to disperse the system. To accommodate the small mass of single mineral available a novel turbidity measurement using a UV/Vis spectrophotometer was introduced. Selected conditions were used in contact angle and small-scale flotation tests.

Jan 1, 2011