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By A. J. Keen

"Cominco's Polaris Mine is an underground lead/zinc operation located on Little Cornwallis Island in the Canadian High Arctic. Polaris is the world's most northerly base metal mine, situated at about latitude 75°N and longitude 97°W (Fig. 1). The closest community is Resolute Bay about 100 km to the southeast.During the construction and development phase Cominco adopted a unique scheme to save time and money. Many facilities including concentrator, powerhouse, shops and warehouse were built on a barge in southern Canada. The barge was towed 4800 km to the site in August 1981. Production at Polaris began in November 1981. The current mining rate is 1 million tonnes per year. The mine employs 250 people with about 190 on site at any time.GeologyThe deposit is a Mississippi Valley type orebody and lies near the top of the Ordovician Thumb Mountain Formation. Ore minerals consist of sphalerite and galena with the gangue being predominantly dolomite with calcite and marcasite. The orebody is situated completely within permafrost, consequently the voids frequently found in the ore are filled with ice. The orebody strikes north-south, dips approximately twenty degrees to the east and takes up an area about 400 m wide by 700 m long. The upper portion of the orebody (60 m to 150 m below surface) lies in an area called the Panhandle Zone. The deeper portion of the orebody known as the Keel Zone extends to 300 m below surface (Fig. 2). The deposit is strongly zoned with a high grade zinc/lead and iron-rich tabular core overlain and underlain by vein, stringer and breccia mineralization. The ore reserves at January 1991 were 14.6 million tonnes at 3.6% Pb, 13.7% Zn, 3.2% Fe, after producing 8 million tonnes at 3.9% Pb and 14.2% Zn since November 1981"

Jan 1, 1992

By H. Rozovsky

"AbstractThis paper discusses the methods of handling air in a large asbestos mill presently being completed at the Jeffrey mine of the Canadian Johns-Manville Company in Asbestos, Quebec.The mill, being the largest single asbestos producer in the world and capable of handling over 14,000 tons of ore per day, requires vast quantities of air. A minimum of 2,500.000 c.f.m. is required or about 10 tons of air for each ton of ore milled.Short descriptions of the process and systems requiring this air are given, followed by details of the fans and filters which make up the heart of the mill.This 'draw through' system, located on the top or 12th floor, is an automatically .controlled volume-pressure system creating the required suction to draw .air throughout the mill building and its numerous air systems.The dry mechanical method of milling develops enormous quantities of airborne dust and fibre. A section of this paper is devoted to a description of the multiplicity of dust systems within a system to control, filter, and remove this dust.Finally, the paper describes the method of returning the filtered air to the• working floors or to the outside, with some notes on heat, humidity and dust counts.IntroductionGeneralTHE discussions in this paper deal only with operations where air movement is involved. No attempt is made to delve into production methods.The Jeffrey mine of the Canadian Johns-Manville Company, located about 100 miles east of Montreal, is the largest single asbestos producer in the world, being responsible for over half of Canadian asbestos fibre production."

Jan 1, 1955

By John Hughes

1. De Beers, Diamonds and Canada 1.1. De Beers was founded long ago (1888, the same time that Canada became a country) in a rural mining village in South Africa. Today, we employ 22,000 people across 19 countries and have 14 mines including open pits, shafts, beach-sands and seabed. 1.2. Last year our sales were US$5.7 billion and our total production amounted to 47 million carats which means a 40% global market share. For the Kyoto buffs in the audience, the company consumes 66 million cubic metres of water per annum, 210 million litres of hydrocarbon fuel and 1,600 GWh of electricity. Stats are good, but aren?t as expressive as a movie. This one is 2 minutes long, which is quicker than I could elaborate. (Video 1 - 2 minutes) 2. De Beers in Botswana is the leading source of diamonds 2.1 Today Botswana is the Jewell in the Crown. There are three big open pits that enjoy economies of scale that make them the lowest cost producers. Last year 60 million tonnes of overburden and 30 million tonnes of ore were moved in Botswana alone. Botswana produced 31 million carats, compared to 14 million carats in South Africa and 2 million very high quality carats inn Namibia. 3. Diamond Mines provide feedstock? ?.to jewellery stores

Apr 1, 2005

By T. Xue, A. Singhal, D. Wrana, I. Mihaylov

"At Vale's Thompson Nickel Refinery, the copper and arsenic in the nickel electrolyte are removed by precipitation using H2S, generating a sulphide precipitate containing about 40% Cu, 8% Ni, 2 to 4% As and 30% S. This residue has been typically stored in impoundment ponds within the plant site. Various options for reprocessing it have been investigated over the years. One of the options involved oxidative pressure acid leach, whereby over 95% Cu, Ni and As were extracted. More recently, an atmospheric alkaline sulphide leaching process for selective removal of 70 to 90% As was developed and mini-plant tested. After alkaline sulphide leaching, the dissolved arsenic is precipitated as stable basic ferric arsenate (BFA) with the addition of ferric sulfate, while the low-arsenic Cu/Ni sulfide is suitable for processing in Vale's operations elsewhere in Canada.INTRODUCTIONVale’s Thompson Nickel Refinery was commissioned in 1961 and currently it has the capacity to produce about 56,700 tonnes per year of electrolytic nickel as cathode slab and rounds products. A sulphate and chloride mixed electrolyte is used in the Thompson refining process and it typically contains 75 to 85 g/L Ni, 50 to 60 g/L Cl, 90 to 120 g/L SO4 2-, 25 to 30 g/L Na and 8 to 9 g/L boric acid. The main impurities in the Thompson anolyte are copper, cobalt, arsenic, iron and lead.The simplified Thompson electrolyte purification flowsheet is shown in Figure 1 (Oliver & Wrana, 2009, Goble & Chapman, 1986); it consists of precipitation of copper, arsenic and lead with H2S, followed by nickel replenishment with ground matte and acid and removal of cobalt and iron with Cl2 and NiCO3."

Jan 1, 2012

By Marc Boyer

Modern civilization, modern industry, and modern standards of living, bring into, sharp relief the present-day essentiality of metals .and minerals, and the wide and diversified use which is made of them. Any attempt, therefore, to appraise the international situation today must take into consideration the metal and mineral resources of the world. If, as some believe, the world is divided into two distinct ideologies of political belief, one unalterably opposed to the other, so that armed conflict is unavoidable, then the question of national strength in mineral resources becomes of paramount importance. If, however, it is possible to avoid war by raising the standard of living in the underdeveloped ?areas of the world, thus ensuring all peoples everywhere against the dread spectres of starvation and disease, then the development of the world's mineral resources assumes even greater importance. Today it is difficult to realize that, prior to the industrial revolution in Great Britain, only a few of the metals and minerals now in common use entered into the everyday life of the people. !iron and steel, copper, lead, tin, and zinc, usually in .their unalloyed forms, along with the more common industrial minerals, were those most widely used, and then only in limited amount. With the advance of technology in metallurgy and in fabricating skills, the list of commercial metals and minerals has expanded until today they number more than eighty.

Jan 1, 1951

By P. J. Noakes

Remote and isolated, located in a frigid, hostile environment, the Black Angel mine in Greenland had to create a warm social environment which would help attract and retain a stable work force of miners and support staff. The high cost of personnel turnover plagues many mines and, when the mine is inside the Arctic Circle, accessible by helicopters which are highly vulnerable to unpredictable weather conditions during the long, dark winters, the potential costs of personnel turnover become critical factors in the success or failure of the mining venture. Manpower planning should start from the date the engineers begin the technical design of the new mine. The plan should include provisions not only to ensure an adequate, skilled work force, but also to ensure a stable work force of people who are happy enough in the mining environment to want to remain, take their vacation and return to work at the mine. The skilled work force was assured with training courses of four months, designed to produce highly specialized underground workers from unskilled Danes and Greenlanders supported by trained Swedish and other Scandinavian miners. The stable social unit was assured by plans the primary attribute of which had to be flexibility. The accommodation changed from shared accommodation with communal washroom facilities to single accommodation with private washroom facilities. A recreational director was hired to help the workers make use of elaborate recreational facilities. A closed-circuit TV and radio system was installed to operate as a private broadcasting system using taped programs originally broadcast on European TV networks or developed by the mine personnel themselves. The liquor rules were changed and the mine manager became a licensed innkeeper responsible for the orderly operation of the Black Angel Bar in accordance with the Danish laws governing the services of a public bar. The result is a relatively stable work force. Some 35% of the people have more than two years' service with the company, Greenex A/S, and some 62% complete 10 months of service.

Jan 1, 1978

By Jun Wang, Bo Zhang, Wenqing Qin, Guanzhou Qiu, Xiaozhen Ma, Key Lab of Biohydrometallurgy of Ministry of Education, Fen Jiao, Central South University, Yansheng Zhang

"Arsenic contained in minerals sulphides such as enargite and tennantite can represent not only a significant penalty element in base metals production, but also a disadvantage to the environment through producing the toxic emissions to the atmosphere. The achieving separation of arsenic bearing minerals either at an early stage in floatation or from the floatation concentration is significantly beneficial to the economic. However, there was no feasible commercial method of separation at the flotation stage because of its similar flotation properties with many other copper sulphides. In this work, the selective floatation of enargite from copper sulphide concentrate containing maily covllite, chalcoctie, bornite and enargite was investigated. A low arsenic concentrate with As 0.2%, Cu 22% and a high arsenic bulk concentrate with As 7.65%,Cu 33.65% were obtained. It was indicated that Ca(ClO)2 is the effective depressor and the optimum floatation condition was obtained. Most enargite could be floated at pH 11 and controlling the pulp potential at 290 mV SHE. Furthermore, the arsenic removal from the high arsenic bulk concentrate by hydrometallurgy methods was study. The results showed that the reaction temperature and the concentrations of NaOH were the most important variables affecting the rate of arsenic removal. A low arsenic concentrate with As 0.24%, Cu 37.80% was obtained in the optimum leaching condition.INTRODUCTIONArsenic is mainly produced as a by-product of base metals smelting, in particular copper concentrate. China has imposed an upper limit of 0.50% arsenic for concentrates entering (Long et al., 2012). Arsenic amount of copper concentrate within 0.40% has also been imposed in China, and above which will be introduced about 50 RMB penalties per ton for each 0.10% increasing by smelters now. Therefore, it is necessary to remove arsenic from the copper concentrate.In copper concentrate, arsenic is mainly in the form of arsenopyrite (FeAsS), enargite (Cu3AsS4) or tennantite (Cu12As4S13). There are two types of arsenic in the separation of copper and arsenic: arsenopyrite and arsenic bearing copper mineral. It is easier to separate arsenopyrite from the copper sulphide by flotation in comparsion with the separation of enargite or tennantite from non-arsenic copper minerals (Pineda et al., 2015). The main difficulty in the separation of arsenic copper mineral from non-arsenic copper sulphides is their extremely similar floatability, which depends on the fact that tennantite and enargite contain high copper content (Pineda et al., 2015)."

Jan 1, 2016

By H. McLeod

Introduction In the period from 1939 to the present, Canada has experienced a remarkable industrial expansion, rising to probably seventh in rank amongst world countries. In the early part of this period, the desperate need for military supplies unloosed tremendous amounts of capital for building new factories and for expanding and converting existing facilities. Mines, factories, and other divisions of the industrial economy bent every energy toward greater and greater output. The result was an 80 per cent increase in the volume of the nation's production within a period of four years, a truly remarkable accomplishment and one in which the mining industry had a very vital part. After the critical year, 1944, the tempo of industry eased off a bit, dropping approximately 20 per cent by 1946. At this time the prospects or post-war industry were clouded by monetary and political chaos in overseas countries, by trade restrictions, and by market uncertainties. There was, of course, a pent-up demand, both at home and abroad, for civilian goods that had been curtailed during the war and for capital equipment that had been destroyed. In the midst of this world-wide uncertainty, if anyone had ventured to predict that by the end of 1950 Canada's industrial output would be back to the 1944 level and humming along at nearly twice the best pre-war pace, he would have been considered rash indeed. Yet this has been the case.

Jan 1, 1951

By Louis R. Bernier

Since 1978, most systematic studies of AMD passive treatment with limestone drains (LD) have dealt with coal mines in the United States. The authors present in this paper the first results of a triennial study initiated in 1999 on the performance of LD installed at the Ni-Cu Lorraine old mine site in Temiscamingue during a remediation plan that involved the installation of a cover with capillary barrier effects (CCBE) over the reactive pyrrhotite-rich tailings. Typically, a LD is a trench enclosed by impervious materials filled with crushed limestone and may be oxic or anoxic. Four LD (one filled with marble and 3 with dolomite) were installed at the Lorraine site. The LD have been in operation since May 1999 and are performing differently. The most contaminated mine effluent flows south and is directed towards 3 LD filled with crushed dolomite, while a 4th LD was filled with crushed marble and installed west. The LD filled with marble has been generating maximum alkalinity since the beginning of the passive treatment. Two of the dolomite drains have been generating alkalinity since mid-summer 1999, but one is not, even if a substantial pH raise was observed. A pH above 5.5 is required usually for the dolomite drains to start generating alkalinity. The installation of LD at the Lorraine site contributes significantly to the reduction of metals and sulphates loading.

May 1, 2001

By Tom Cooney

A small number of mining contractors worldwide have evolved their businesses to be able to provide a ?total service solution? to their clients. Thiess, an Australian-based international mining service provider, works with numerous clients to tailor delivery methods and commercial arrangements to suit individual projects. The benefits of Thiess? extensive experience is brought to each client and project, whilst business improvement within projects, to the mutual benefit of both the client and Thiess, is a key part of all long term contract relationships. Historically, optimal business outcomes were closely related to the achievement of production and cost performance measures. Whilst these remain fundamental to successful mining businesses, other elements of sustainability are assuming increasing importance. As a large energy user, greenhouse and energy management is becoming an important part of Thiess? business. Thiess is a signatory to Australian government initiatives such as Greenhouse Challenge Plus, and is integrating energy management into its operations and business improvement programs, in many cases to the benefit also of the client. This paper will highlight the benefits that an organisation such as Thiess can bring to a mine owner. Thiess? approach to business improvement and cost reduction, sustainability and energy management, as well as the relationship between these will also be considered. Increasingly, overall mining performance is dependent on the alignment of formally disparate elements.

May 1, 2007

Cansolv® S02 Scrubbing Technology was described in a paper in Copper/Cobre 03. Four years on, the technology is operating at a full scale production facility.Hindustan Zinc Limited expanded their capacity by installing the AUSMELT process. The process proceeds through smelting, slag reduction, slag cleaning and holding stages sequentially in the same vessel, resulting in widely varying off gas characteristics. The off gas is suitable for treatment is a conventional acid plant for a modest proportion of the day, but at other times produces off gas too high in S02 to be discharged to atmosphere. Cansolv® S02 Scrubbing Technology was identified as a means of effectively removing the S02 down to low levels from the off gas during all stages of the pyrometallurgical process. Furthermore, the Cansolv® S02 Scrubbing System Technology produces high purity S02 that allowed for the captured S02 to be directed to an existing acid plant, avoiding the capital cost of new acid making capacity.

Jan 1, 2007

By H. Bouzahzah

Sulfidic tailings, subjected to atmospheric water and oxygen action, can generate acid mine drainage (AMD); which is the most important environmental problem facing the mining industry. AMD generating potential can be assessed by the static tests which consist of a screening method where the neutralization potential (NP) and the acid-generating potential (AP) of a given rock sample are determined. The AP and NP are determined separately in the different static test existing procedures which can be divided into two distinct classes: chemical and the mineralogical methods. For some chemical method, the AP is calculated on the basis of total sulfide sulfur content in the sample which may overestimate its AP if significant quantities of non-sulfide sulfur species are present (e.g. organic S in coals, some sulfate as gypsum, barite, etc.). However, the mineralogical method evaluates the AP by the sum of the individual sulfides participation on acid generation based on their concentration within the sample and can be more accurate than the chemical method. For AP calculation, the Paktunc (1999a) mineralogical static test takes into consideration all sulfide minerals occurring in the sample. However, it does not take into account the rates of acidity production of these sulfides submitted to weathering conditions. So, the present study focusses on the modification of Paktunc AP calculation by considering the acidity production rates of these minerals. To reach this objective, five base-metal sulfides (pyrite as reference, chalcopyrite, sphalerite, arsenopyrite, galena), diluted within quartz (25?75 wt.%) simulating mill tailings were subjected to a kinetic test to evaluate their AP. The results show that all the studied sulfides minerals generate acidity at different rates, so the Paktunc?s equation for AP calculation has been adapted accordingly.

Aug 1, 2013

By G. Wren

As base metal sulphide resources become increasingly challenging to process, producers seek alternative options to treat concentrates. This study considers the mineral, elemental, and leaching character of a West Australian nickel sulphide deposit (Cosmos Nickel Project). After a brief review of the published work bench top leach tests were conducted to examine the factors which impact the kinetics of nickel sulphide leaching such as particle size, temperature, acid strength and type, concentration of copper sulphate and sodium chloride, and oxygen partial pressure. The effect of sodium chloride was considered due to the common occurrence of hyper saline water at West Australian nickel sulphide mine sites. Ultrafine grinding to an 80% passing size of 10 µm resulted in high nickel leaching efficiency. Moreover, higher concentrations of acid, copper(II) and sodium chloride also gave higher nickel and cobalt leaching efficiencies but arsenic precipitated as FeAsO4. Under the most suitable conditions the extractions of nickel, cobalt and arsenic at 90oC after 6 hours were >95%, 90% and <5%, respectively. The comparison with results from high pressure operations indicates the possibility of using a hydrometallurgical flowsheet based on fine grinding and atmospheric pressure leaching and warrants further investigations.

Jan 1, 2014

By V. S. Gischig, G. Preisig

Hydraulic stimulation of deep reservoirs is an essential procedure for developing engineered/enhanced geothermal systems (EGS), but also in other Geo-energy contexts. The goal is enhancing permeability to such a degree that fluid flow rates within the reservoir are sufficiently high for an economically productive reservoir. Two fracture stimulation mechanisms are distinguished that may occur concurrently during the hydraulic treatment: 1) During hydro-fracturing (HF) new tensile fractures are propagated from the borehole by means of a fluid pressure overcoming the minimal principle stress d3 plus the tensile strength T0 of intact rock. In case of a pre-existing fracture oriented normal to d 3 , the fracture can be opened by exceeding d 3 only. Fluid injection is performed via small packed intervals for creating a stack of hydraulic fractures. 2) During hydro-shearing (HS), over-pressure induces slip along pre-existing fractures that are favourably oriented in the stress field for reactivation in shear. Such stimulation is usually performed in a large packed interval or in an open borehole. Which mechanism occurs predominantly during stimulation depends on the rock mass structure and in-situ stress field, but also on the orientation of discontinuities intersecting the open-hole section and thus being pressurized. Both mechanisms also differ in how they affect fracture permeability. While permeability gained by HS is mostly irreversible due to rearrangement of asperity contacts accompanied with shear dilation, permeability enhanced during HF reduces nearly reversible after pressurization unless proppant is used to ensure permanent apertures. In this contribution, we critically discuss the pros and cons of both mechanisms regarding efficiency of enhancing permeability and the associated hazard of induced earthquakes based on literature review and numerical modelling. We review literature that reports on how much permeability required for productive EGS reservoirs and how much permanent permeability can be gained by stimulation. We also compile information regarding the degree of seismicity induced during HFor HS-dominated stimulation procedures, together with conceptual studies that reveal characteristics of seismicity associated with the two mechanisms. Many observations and models indicate that HF may have a higher tendency of being aseismic, while felt seismic events are usually associated with HS. Further, we present a hydro-mechanically coupled fracture flow model that investigates, if and to what degree the stimulation strategy can be designed such that one of the two mechanisms is evoked and dominates over the other. It shows that HS may dominate in presence of larger persistent fractures nearly optimallyoriented in the stress field, even if HF is attempted in short packed intervals. The model further demonstrates that stress transfer during HS promotes the development of permeability across an anisotropic layer of the stimulated rock instead of a large volume. Hence, the study sheds light onto the feasibility of creating productive EGS reservoirs in crystalline rock at several kilometres depths.

Jan 1, 2015

By Tracey Bodnarchuk, Philipp Mirzoev

Sulfate balance control is a common problem for zinc plants. Roast-leach-electrowin plants are mostly concerned with the over-generation of sulfates while for the HudBay direct leach plant both extremes are possible including potential necessity to buy sulfuric acid to replenish a sulfate-depleted circuit, which makes the problem doubly important. Quantitative methods were applied at the HudBay plant to analyze sulfate generation/depletion based on a local sulfur balance and sulfate extraction calculation in the leach circuit, using a Pb-tie method. Main factors were established influencing sulfate generation/depletion, including the critical role of Pb and pyrite. Regression analysis proved to be effective and allowed the quantitative prediction of Pb concentrations necessary to reach the equilibrium for the sulfate balance. This in turn provided a firm basis for a sulfate-control strategy realized through concentrate blend correction, which allowed the plant to fine-tune sulfate generation/depletion effectively reducing economic consequences of excessive/deficient sulfate generation.

Jan 1, 2015

By Webber. G. R.

Variation in content of some of the major and minor elements in the Lake Dufault granodiorite near Noranda, Quebec has been studied. The element variation and specific gravity data show a pattern consistent with the concept of a concentrically zoned intrusive on the western side of Lake Dufault with a potassium-rich core and a calcium-rich inner zone. The part of the intrusive on the eastern side of Lake Dufault is of more problematical origin, but the suggestion is made that it has resulted from assimilation of volcanic rock by the intrusive. THE purpose of this investigation was to test the application of x-ray fluorescence analysis to the study of variation in chemical com-position of the Lake Dufault granodiorite. The Lake Dufault granodiorite is an intrusive body approximately six miles long by three miles wide located four miles north of Noranda, Quebec. This intrusive is of particular interest because of its -

Jan 1, 1962

By T. H. Peters

The historical development of this program, dating from the construction of Nickel Park at Copper Cliff in 1917 to the various current projects carried out in the Ontario Division&apos;s program, is reviewed. Practices used to grow vegetation on stressed areas, the beneficial aspect of the improved aesthetic appearance of company properties from the point of view of public relations and the improved approach to the workplace by the employee are discussed. The revegetation of the tailings area and its gradual transformation into a Wildlife Management Area is reviewed.

Jan 1, 1978

By J. Zollinger, J. R. Kennedy, J. H. Park, D. Daloz

"In order to improve the properties of cast Ti-Al alloys to replace Ni-based superalloys past the low pressure stages of aircraft engines investigations into inoculation for grain refinement were carried out. Previous work showed isomorphic self-inoculation using Ti-Al-Nb particles was effective for grain refinement, however the relatively fast diffusion of Nb in Ti-Al make it difficult to observe the mechanism of nucleation. An alternative alloy was developed in the Ti-Ta system for isomorphic self-inoculation, maximizing the Ta content to improve the particles survivability in the melt. The powder processing produced comparatively small inoculant particles which dissolved, however larger particles were seen to survive solidification. The density difference between the inoculant particles and melt resulted in an inhomogeneous mixing of the particles and the melt with larger particles found near the outer edges of the ingots. Variations on particle size and interaction time between the inoculants and the melt resulted in the Ti-Ta inoculant reducing the as-cast equiaxed grain size by a factor of two compared to non-inoculated samples as well as increasing the equiaxed fraction in the ingot.INTRODUCTION Lightweight metals are of particular interest in aerospace applications. The hot sections of turbines are dominated by blades made of nickel based superalloys. Recently the GEnx turbine introduced TiAl blades in the last low pressure stage of the turbine to reduce weight and improve fuel efficiency (Kim & Dimiduk, 1991). In order to carry these benefits deeper into the turbine the high temperature (>800oC) properties of the alloys must be improved. Current grain refinement methods to improve properties rely on boron additions which may not be applicable for all blades as brittle precipitates may be formed during processing (McCullough, Levi, Mehrabian, & Hyman, 1991). A novel grain refinement process was previously introduced called “isomorphic self-inoculation” using Ti-Al-Nb particles to successfully grain refine TiAl (Kennedy, Zollinger, Bouzy, & Daloz, 2016). In order to better understand the mechanism of this process an investigation was carried out using the same process but with a Ti-Ta alloy which is more stable in the TiAl melt than the Ti-Al-Nb."

Jan 1, 2017

By M. Jackson, R. McDonald, T. Osken, D. Robinson

"The addition of sulphidic materials in the leaching of nickel laterites has several potential benefits that include improvements in the rheological behaviour of the blends, reductions in the sulphuric acid and steam requirements, sweetening of the nickel grade of the combined feed material, and the option of using a range of sulphidic materials. The current study examines the oxidative processing of 30% w/w blends of nickel concentrate and nickel laterite ore at 250oC. In particular, the viability of using low oxygen overpressures was examined for significant amounts of nickel flotation concentrate, up to 12% w/w. Further to this the impact of process water quality, in particular the presence of chloride, upon the kinetics of extraction and the mineralogy of the residue were also investigated. This paper will present the results of preliminary work in this area.INTRODUCTIONThe use of sulphidic ore as a source of sulphuric acid during oxidative hydrometallurgical processing is not a novel idea and can be traced back over forty years (Seidel & Fitzhugh, 1968). A series of patents pertaining to application of this approach for laterite ores can be subsequently found (O’Neill, 1973; Opratko et al., 1974; Rodriguez, 2008a, 2008b; O’Callaghan, 2010; Liu et al., 2011) and a few of articles containing published data (Ferron & Fleming, 2004; Quinn et al., 2009). The use of pyrrhotite tailings as a source of sulphuric acid has also been employed for the leaching of converter slags (Perederiy et al., 2011).It is known that hydrometallurgical operations such as the HPAL plant at Murrin Murrin have added small amounts of sulphides as either transitional (mixed sulphide/oxide) ore or non-smeltable concentrate. This can improve the rheology (Rodriguez, 2009) and provide heat credits. However these plants are generally limited in their ability to add such materials due to their reducing nature and given under highly acidic conditions that the breakdown potential of the titanium used for the autoclave lining is significantly reduced. A suitable oxidant must therefore be present to ensure the potential remains sufficiently high."

Jan 1, 2012

By Rosie Moore, Harvey Keats, Kerry Sparkes, A. J. Naldrett

"Abstract-The Voisey’s Bay Ni-Cu-Co deposit was discovered in late 1994 as the result of prospecting initiated in the summer of 1993. By July 1995, proven mineable reserves were 31.7 x 106 tonnes grading 2.83% Ni, 1.68% Cu and 0.12% Co, and current total resources in all categories are quoted to be in the order of 150 X 106 tonnes. The deposit is associated with a body of troctolite belonging to the Nain Anorthosite (1.35 Ga - 1.29 Ga) suite, which was emplaced across the boundary between the Proterozoic "Rae" Province to the west and Archean "Nain" Province to the east.The deposit can be described in terms of three geological settings. The "Ovoid" is a 600 m long by 350 m wide by 100 m deep lens of massive sulfide, covered by 10 m to 20 m of glacial overburden, and separated from the underlying country rock quartz-plagioclase-biotite gneiss by a breccia of gneissic fragments in troctolite known as the Basal Breccia Sequence. To the west of the Ovoid lies the "Western Extension", comprising disseminated and massive sulfides in a north-dipping sheet of troctolite which ranges from upper unmineralized troctolite down through troctolite with increasing amounts of sulfide (up to 50%), to massive sulfide (in some places only), and then to Basal Breccia Sequence. East of the Ovoid, the troctolite sheet broadens out into a troctolite intrusion, within which occurs the "Eastern Deeps", a zone of massive and disseminated sulfide up to 100 m thick that is currently being explored. The mineralization of the Eastern Deeps lies along the line of intersection of a feeder sheet with the base of the intrusion. The current interpretation is that the three geological environments represent different erosional levels through a single mineralized intrusion. In this model, the deepest erosional level lies to the west and exposes the feeder to surface, whereas the Ovoid represents the base of the intrusion at surface, and the Eastern Deeps the base of the intrusion overlain by 600 m to 900 m of troctolite. Sulfides and gneissic fragments were brought up by magma flowing quickly through the feeder, and settled out where the flow rate decreased as the sulfide-bearing magma mixed with magma already emplaced in the intrusive body."

Jan 1, 1996