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By David M. Knowles, R. Gordon Gastil

"The Precambrian sedimentary series of the Labrador geosyncline, including iron formation, extends into southwestern Labrador and adjacent Quebec. The iron formation consisted of primary oxide, silicate, and carbonate facies which were deposited simultaneously in an irregular basin in response to migratory environmental conditions. The iron formation isochemically recrystallized to coarse-grained quartz-iron oxide, iron silicate, and quartz-iron carbon-ate rocks during prolonged regional metamorphism. The rocks are deformed on two deformation axes intersecting at large angles, and are characterized by isoclinal to recumbent folds. Parts of the formation have been profoundly affected by a post-metamorphic leaching and oxidizing environment."

Jan 1, 1959

By Juan Asalgado

The JORC and NI43-101 codes impose that mineralized material has a reasonable prospect of economical extraction to be classified as Mineral Resource. For deposits close to surface and amenable to open pit mining, it is easy to show reasonable prospect of economic extraction running a Lerch-Grossman optimization. The Lerch-Grossman pit provides a transparent and repeatable way of separating the Mineral Resource (within the pit) from the remainder of the mineral inventory (outside the pit). Deposits amenable to underground mining are more challenging because of the variety of the underground methods. AMEC developed a stand-alone software package that outlines the material which has reasonable prospect of economic extraction for open stoping, block caving, sublevel caving and room and pillar. The software takes a block model file in ASCII and exports a 3D surface outlining the part of the mineralization that has a reasonable prospect of economic extraction, and which the Qualified Person can smooth out manually if required.

Oct 1, 2009

By W. G. Mine

In September, 1953, seismographs were installed in the Crowsnest Pass area of Alberta and British Columbia to study the 'bumps' which were occurring in the coal mines at Fernie and Coleman, and to investigate the possibility that they might be related to minor earthquakes in the area. During the initial phase of the work, three seismographs were operated at widely separated stations, two in the region of coal mines at Coal Creek and Coleman and one at Turner Valley, distant from any mining operations. Some earthquakes were recorded at all three stations and, in addition, many small disturbances were recorded by the seismographs located near the mines, especially -by the instrument at Goal Greek. A closer network of radio-linked seismographs was then in-stalled near Fernie, the records of which definitely established that the small disturbances were occurring in the mine workings, both active and inactive. No relationship was established between bumps and local earth-quakes in the area. This work was initiated as a -co-operative effort with the Fuels Di-vision of the Mines Branch, Department of Mines and Technical Surveys, which has undertaken a study into the phenomena of ground stress relief in underground mine workings.

Jan 1, 1958

By A. G. Eccles

Western Mines' milling circuit produces three concentrates (copper, lead and zinc), with the tailings being disposed of at the bottom of Buttle Lake. In view of the mine's location and the method of tailing disposal, a comprehensive pollution control program has been in effect since start-up. Changes -in the ore over the past few years have required the use of increasing quantities of sodium cyanide in order to effect a good copper-lead separation. This led to the use of alkaline chlorination for destruction of ?residual cyanide and precipitation of dissolved copper contained in the tailing effluent. The development of Western Mines' alkaline chlorination plant is discussed in detail, including initial test work and the evolution of procedures leading to the present operation. The current monitoring program is also reviewed.

Jan 1, 1977

By C. Velásquez, W. Bergholz, C. Spence, P. Lind

NuevaUnión SpA (NuevaUnión) is a development project located in the Huasco province of the Atacama region of Chile. It is held in a joint venture company owned 50:50 by Teck Resources Limited (Teck) and Newmont Goldcorp. It includes the Cu-Mo Relincho deposit and the Cu-Au La Fortuna deposit, with plans to utilise a single concentrator to be built at the Relincho site. The Relincho site is at an altitude of 2,000 masl and is 40 km from the La Fortuna site which is at an altitude of 4,100 masl. The project is currently completing a Feasibility Study and is reviewing equipment selection and flowsheet options. This paper is based on the current thinking, and design decisions will be finalized at the completion of the Feasibility Study. NuevaUnión is currently planning for phased operation, processing Relincho ore at 104 ktpd followed by processing ore from La Fortuna at 116 ktpd. Plans for the third phase include doubling the main processing lines and returning to Relincho ore at a processing rate of 208 ktpd. The NuevaUnión concentrator will incorporate comminution and flotation circuits that are being designed to maximize the overall economic value of the combined ore deposits. Major ore characteristics differ between the two ore bodies, such as ore competency, grindability, liberation grind size, pulp rheology, tailings properties, minerals and metals of value, as well as gangue mineralogy. Mineral processing choices have been made to optimise value from each deposit and the combined project. INTRODUCTION Between 2010 and 2013, two significant mining projects were being developed in Chile: Goldcorp’s El Morro project had recently finalized a Feasibility Study and, in 2011, had received its environmental approval for construction; and Teck Resources Limited’s (Teck) Relincho project was finalizing a Feasibility Study and preparing its Environmental Impact Study. Both projects were: Geographically close, at only 40 km apart. Considering similar infrastructure. Each was planning to have its own concentrator, tailings management facility, high voltage power line, port, concentrate transport system, seawater desalination plant and pumping system to mine site.

Jan 1, 2019

By W. T. Boyes, J. M. Harrison

"Squall Lake Gold Mines, Limited, owns a group of claims at Squall lake, northern Manitoba, about 75 miles east of Flin Flon and 3 to 4 miles north of the Nor-Acme mine at Snow lake. Gold mineralization was discovered in this locality several years prior to 1944, but it was only in that year that a comprehensive examination of the occurrences was begun. Development work to the end of 1946 has been encouraging and the deposits show interesting relations to rock structure.GEOLOGICAL SETTINGThe gold occurs in a sill of biotite-hornblende diorite at or near its contact with gneisses derived from arkosic sediments . In detail, the contact between the diorite and the arkose to the southeast of it is irregular, with interfingering of the two rock types. On the northwest side of the sill, between it and Squall lake, the rock is staurolite schist (see accompanying sketch-map).Several mineralized shear zones are known, of which those shown are the most important. Within the zones, the diorite is silicified and somewhat carbonatized. Fairly coarse arsenopyrite is the chief sulphide mineral in these zones but, locally, they contain also pyrite and pyrrhotite. Where quartz and chlorite are present, rather coarse gold is associated with them. In that part of the main zone where gold assays have been most consistent, the diorite is rich in albite."

Jan 1, 1954

By H. J. McQueen

Pyro-reduction of ores to metal products developed markedly through the industrial revolution into the great depression. Nineteenth century resource and environmental sustainability were haphazardly improved by many process changes, although the motivation was primarily reduction in labor, feed stocks and fuel. Some notable achievements were coke and hot air for blast furnaces (later from waste heat stoves), puddling of wrought iron and steel ingot production with convertors advancing into oxygen use and continuous slab, billet and strip casting. Although advances in one sector were often counteracted by fall-backs in others, there was progress in that the resource consumption and pollution per unit of production was decreased. Improvements in the 2 decades following WW2 were mixed but popular notice of environmental hazards forced governments to legislate pollution controls and initiate steps in resource conservation. The energy crisis of the 1970’s saw an industrial energy-saving campaign and legislation of technology assessment procedures. Up until mid 18th Century, the training of iron masters depended on apprenticeship with some formalized knowledge from medieval books such as those of Biringuccio (1540) and Agricola (1556). The advances were very slow partly due to absence of scientific concepts of the smelting process. Nevertheless, some iron masters succeeded in improving the process and described procedures to instruct others. With the surge of steam power and the reverberatory puddling process for ductile wrought iron (WI), machinery changed from wood (iron strap reinforced) to WI machinery. With the clarification of the reduction and oxidation mechanisms by Cavendish and Lavoisier (~1780), productivity in iron production surged. The mechanical testing and microscopy of Kirkaldy (1862) spurred understanding of processing and properties of WI and steel. The various forms of C in steels were determined by chemists at the end of the 19th Century. It also became possible to control metal and slag chemistry in the open hearth furnace. But understanding of the transformations during heat treatment of steel only came in the first decades of the 20th Century.

Jan 1, 2012

By Michael Young, Peter Allum, Mingwei Gao

"Tough economical conditions and high grade but fine-grained ore processing have forced the mining industry to look for more efficient processes. Isa Mill Technology for ultra-fine and fine grinding is one such process employed at several mining operations in Australia including Mount Isa Mines Limited in Australia. Mount Isa Mines is a business unit of MIM Holdings Limited. MIM is an Australian-based international mining and mineral processing company with around 8000 employees worldwide. Major products include copper, gold, zinc-lead-silver, coal and technology sales.The Isa Mill is a horizontal stirred mill with sizes up to 3 m3 chamber net volume and 1 120 kW installed motor. It was jointly invented by Mount Isa Mines of Australia and Netzsch Feinmahltecknik GmbH of Germany for ultra-fine and fine grinding duties in the minerals industry. Isa Mill operations started in 1994 at the Mount Isa Mines Leadzinc Concentrator and then at MIM’s McArthur River Mine in 1995. These Isa Mills have been used to liberate sphalerite and galena at Mount Isa and silica at McArthur River by grinding to less than 7 micron.This paper discusses the Isa Mill Technology and reports on the metallurgical performance of the Isa Mills at Mount Isa Mines, including work done over the last 9 years to improve mill design, process efficiency and maintenance, which has resulted in the current state-of-the-art Isa Mill Technology.INTRODUCTIONThe current leadzinc deposits at Mount Isa Mines (George Fisher, Hilton and Isa) have an average grade of 10.5% zinc, 7.2% lead and 165g/t silver. Fine grinding, in particular in the zinc retreatment circuit requiring a milled product P80 of 7 micron, is essential to treat the ores from the Mount Isa Mines deposits. Every one micron size reduction in the zinc retreatment circuit below a P80 of 10 micron improves the overall plant zinc recovery by 1%, resulting in an increase in revenue of about 1 million dollars per annum."

Jan 1, 2002

By S. N. Dixon

"Maximizing the value of each tonne of processed ore is the goal for all operations. Cyanidation processing of gold-copper ores has been challenging since its first use in 1889. The current practice treats a bleed or the total flow of mill solution to recover copper as copper sulfide (by sulfidization, acidification, recycling, and thickening), or to recover the cyanide (by acidification-volatilization neutralization). The process presented uses the adsorption of copper cyanide by carbon and the selective elution of copper from carbon to concentrate copper into a smaller stream. Copper contained in the smaller stream is precipitated as copper cyanide.RÉSUMÉ Toutes les exploitations ont pour objectif commun d’optimiser la valeur de chaque tonne de minerai traité. Depuis sa première utilisation en 1889, la méthode de traitement par cyanuration des minerais aurifère et cuprifère s’est révélée complexe. La pratique actuelle traite la saignée ou le débit total d’une solution de traitement du concentrateur pour récupérer le cuivre sous la forme de sulfure de cuivre (par sulfuration, acidification, recyclage et épaississement), ou pour récupérer le cyanure (par acidification, volatilisation et neutralisation). Le procédé présenté dans cet article utilise l’adsorption sur charbon actif de la solution de cyanure de cuivre et l’élution sélective du cuivre depuis le charbon pour concentrer le cuivre en un plus petit jet. Le cuivre contenu dans ce plus petit jet est précipité sous forme de cyanure de cuivre.INTRODUCTIONProcessing gold-copper ores by cyanidation has been a cost-control challenge since the cyanidation process was first used in 1889. Copper cyanide is stable only in the cuprous state, not the cupric. This factor results in the oxidation of a mole of cyanide per mole of nonchalcocite copper extracted. Each mole of copper extracted forms a cyanide complex with a minimum of 3 mol of cyanide. This cyanide-to-copper mole ratio is required to dissolve gold. The oxidation of cyanide and copper complexation with cyanide results in high cyanide consumption for copper-gold ores, which is a significant operating cost.One challenge in processing gold-copper ore is the cost of cyanide related to the extraction of copper. Processing 10,000 t/d of ore containing 1,000 mg/kg copper and 10% copper extraction yields 1,000 kg/d of copper. Currently, processes to remove copper from cyanide leach solution treat either the total flow of the barren or a bleed of the barren. The two processes used for copper-gold ores are sulfidization, acidification, recycling, and thickening (SART), which produces a copper sulfide product for sale; and acidification- volatilization-neutralization (AVR), which recovers the cyanide from a gas and produces a low–cyanide content solution. This low–cyanide content solution can be recycled to the process or might require additional treatment before being disposed from the operation."

Jan 1, 2017

By Fridrik J. Kristjansson, Stephen R. Hicock

"Three varieties of till are recognized in the Beardmore-Geraldton area: local lodgement till, nonlocal carbonate till, and local supraglacial till. The local lodgement till unit is examined in detail for the first time in this paper. It is the best potential overburden exploration medium for gold and other metals because its particles were locally-derived and deposited subglacially, probably within a few kilometres downglacier (southwestward) from their sources, and have not been diluted by distantly-derived glacialdebris. Both local tills are richer in gold and other metals, relative to nonlocal carbonate till. Local lodgement till rests on bedrock and was encountered frequently at or near the surface in thin drift/bedrock terrain (a widespread terrain type within the west half of the study area), and commonly at the base of boreholes in thick till terrain.INTRODUCTIONDrift prospecting in areas of glaciated terrain has been well documented (in a variety of journal publications and symposium volumes; e.g . Strobel and Faure 1987; MacDonald and Mills 1988) and has proven valuable especially where overburden thicknesses hinder traditional exploration techniques. Drift prospecting techniques may well prove valuable in the Beardmore Geraldton area. This applies especially to the Wildgoose Lake Turkey Lake area where a thick and laterally extensive sheet of nonlocal carbonate till has impeded conventional mineral exploration programs (Fig. I; note the lack of gold occurrences around Wildgoose Lake).Till in .particular has been cited as the best prospecting medium among the various types of glacial sediment (e.g. Shilts 1984). Three end member till varieties are recognized in the study area: (I) local lodgement till which rests directly on bedrock; (2) non local carbonate till; and (3) local supraglacial till which occurs predominatly within, or just downglacier of, upland areas where it commonly mantles the other till varieties. Previous authors have documented how the non local carbonate till hinders gold exploration (Geddes and Kristjansson 1986; Karrow and Geddes 1987; Kristjansson 1986; Hicock 1986, 1987a, b, 1988; Kristjansson and Thorieifson 1987; Thorleifson and Kristjansson 1987, 1988a, b) and why the local supraglacial till may be a good unit for prospecting (Hicock 1986). One detailed surficial geology map sheet of the area has been published (Kristjansson et al., 1988) and others are in preparation. Closs and Sado (1981) reported on the geochemistry of soils and glacial sediments in the west half of the study area. This paper documents the local lodgement till unit and demonstrates why it is the best overburden unit to use for drift prospecting."

Jan 1, 1989

By T. G. Joseph, M. Welz

ABSTRACT: Joseph (2002) introduced passive seismic monitoring to measure mining equipment performance. This paper evaluates the potential of passive seismic monitoring to correlate mining equipment operation with oil sands surface response, with a mining hauler as the seismic source. When applied to moving haulers, this action–reaction approach is complex. Vibrations from on-board equipment, such as pumps and tires, dirty the signal with noise. To facilitate any correlation, the signal must be cleaned up. Existing geophysical analytical techniques were manipulated to evaluate the noise problem and to filter sufficiently to permit an evaluation of whether a mining equipment action–ground response relationshipis in fact discernable.

Jan 1, 2011

By J. Hoover

"IntroductionThis chapter will discuss the operational and maintenance aspects of a heavy media cyclone circuits as applied to coal processing and using magnetite as the media. It deals with heavy media bath separators in terms of types of media, equipment, circuits, media recovery, maintenance, and product handling. It will detail heavy media cyclone operation and supplement the previously described topics.The heavy media cyclone was first developed in the Netherlands by the Dutch State Mines in 1945. A cyclone plant was not built in North America until 1961. Traditionally, heavy media cyclones have been used to treat size fractions between 1lz in. (12 .6 mm) and 35 mesh (0.5 mm). High maintenance related to heavy media bath separators has recently prompted some plants to crush all raw coal to minus 2 in. for treatment in heavy media cyclones.The heavy media bath separators utilize only the force of gravity to make the separation between heavy and light particles. This requires lengthy retention time which can lower capacity and also is inefficient for finer particles. A heavy media cyclone utilizes centrifugal forces which are 20 to 200 times greater than the force of gravity. This means the separation between coal and the impurities occurs very quickly, therefore a low retention time is required allowing cyclones to have high tonnage capacities. Also these greater forces allow better separation for the finer particle sizes.Heavy media cyclones are now widely used to produce both metallurgical and thermal coal. Work is in progress to reduce magnetite consumption, extend wear life, increase tonnage capacity, improve separation efficiency and automatically control these cyclone circuits."

Jan 1, 1989

By Ian Bruce

Tailings and water management facilities are essential and integral components of mine and mill operations. They must be managed for the long term in order to ensure that safe and environmentally responsible stewardship is achieved. Toward this end, in 1998, The Mining Association of Canada (MAC) published A Guide to the Management of Tailings Facilities, which recommended the implementation of a tailings management framework (Figure 1) to integrate environmental and safety considerations into each stage of the life cycle of a tailings facility, from initial site selection and design, through construction and operation, to eventual decommissioning and closure. By February 2000 it was becoming apparent that while mining companies were making significant progress toward implementing and documenting tailings management systems, and integrating them with overall environmental management systems, further effort was warranted in their application at the operational level. In particular, a need was identified for further guidance in preparing manuals that outline procedures for the safe operation, maintenance and surveillance (OMS) of tailings and water management facilities.

May 1, 2002

By Michael R. McPhie

Topics of Discussion 1. The Global Mining Initiative (GMI) and MMSD North America (Brief) 2. Task 2 of MMSD North America ? A Test for Sustainability 3. The Seven Questions and their Application 4. Key Recommendations and Next Steps GMI = Global Mining Initiative Significant international collaborative effort supported by more than 30 of the world?s largest mining/minerals firms which sought to involve all communities of interest. Three major streams of activities: 1. Mining, Minerals and Sustainable Development Project (MMSD) ? 4 regional Process (North America, Southern Africa, South America, Australia) 2. Creation of ICMM (formerly ICME) 3. Major conference in Toronto in May, 2002

May 1, 2002

By C. R. Fast, G. C. Howard

The loss of fluid to the formation adjacent a fracture governs the areal extent of the fracture and the success of hydraulic fracturing as a production stimulation technique. The three flow mechanisms which control this loss are the result of the viscosity of the fracturing fluid and the permeability of the formation to the fracturing fluid, its wall building properties, and the combined effects of viscosity and compressibility of the reservoir fluid. The effects of these flow mechanisms can be evaluated in terms of a fracturing fluid coefficient, the fundamental concepts of which are developed in the paper. The fracturing fluid coefficient, which may be used in calculating the areal extent of fracturing, affords a direct measure of the effectiveness of fracturing fluids. The area of hydraulically created fractures is in-creased as the coefficient is de-creased. The fifteen-fold variation noted in this coefficient for the commercially available fracturing fluids tested resulted in a six-fold difference m the calculated areal extent of the fracture system.

Jan 1, 1961

By P. Nos, L. Kolbeinsen, M. W. Kennedy, A. Filzwieser, R. T. Jones, A. MacRae

Modern furnace designs often incorporate extensive use of cooled elements to achieve long campaign lives at high operating intensities. However, contact between water and high temperature fluids can result in powerful Boiling Liquid Expanding Vapour Explosions (BLEVEs). Therefore cooling such elements with water carries inherent risks when used under slag and particularly below molten metal or matte. Alternative cooling media exist that can reduce or eliminate the risk of BLEVEs. These media are analysed and discussed in the context of deeply cooled furnace elements. Important factors in selecting alternative coolants are explored including: critical heat flux, thermal limits, toxicity, flammability, unit cost, etc. Key cooling system design criteria are reviewed in the context of both traditional and alternative coolants. Results of Computational Fluid Dynamics are presented for an example tap-block cooler design using a number of selected coolants. Research needs to advance the safe use of alternative coolants are presented.

Jan 1, 2015

"Coupon testing has been used to investigate stress corrosion cracking (SCC) of rockbolts in a laboratory based experimental program. This program has focused on the use of ASTM G39 three- and four-point bent beam coupon specimens, immersed in an acidified sodium chloride test solution containing hydrogen sulfide. The specimens were loaded to a range of stresses from zero, to just above the materials yield strength. It was found that only specimens above an applied stress of 580MPa failed by means of SCC, showing that rockbolts loaded to near their yield strength may be susceptible to SCC in-situ.INTRODUCTIONStress corrosion cracking (SCC) is a failure mechanism that affects material through the growth of hairline cracks when exposed to a corrosive medium while under stress (Jones and Ricker, 1999). SCC has been found to affect rockbolts in the Australian underground coal mining industry and has the capacity to cause the catastrophic failure of ground support systems, potentially leading to falls of ground in underground excavations, injury or death to mine personnel, damage or loss of equipment, and loss of productivity through the loss of roadway access (Crosky et al, 2002).Coupon testing utilises small scale samples that are intended to be indicative of the behaviour exhibited by a material in-situ (ASTM G39). The small scale, and usually high surface area to volume ratio of coupon specimens mean that they corrode at faster rate proportional to their mass, greatly reducing testing times. The small scale of the specimens allows them to be more easily prepared and handled, loaning them to mass manufacturing techniques.A previous study conducted by Vandermaat et al (2012b) into the use of three- and four-point coupon testing in-situ in an underground coal mine failed to result in SCC of the specimens. This paper serves as a follow up laboratory investigation in order to understand why these specimens did not fail. Previous studies into the SCC in rockbolts carried out by Gamboa and Atrens (2003) determined that rockbolt steel has a critical stress threshold of approximately 90% of the material ultimate tensile strength (800-900MPa). This study will focus on this critical stress threshold as a possible explanation for the lack of failure in the in-situ specimens (Vandermaat, 2012b)."

Jan 1, 2015

By C. A. Young, H-H. Huang, L. G. Twidwell

Solid particles, especially oxides/hydroxides, develop an electrical charge on their surface when submerged in aqueous solution. Parks was able to relate PZC (point of zero charge) of an oxide to its minimum solubility and isoelectric point. Dzombak has compiled an extensive database for adsorption reactions on ferrihydrite surfaces using the double layer theory. The equilibrium calculational program, STABCAL has been used to extend the considerations of Parks and Stumm. The PZC for many hydroxides, complex oxides, and non-oxides have been investigated and the results are reported in the literature. Removal of arsenic and metals by adsorption on ferrihydrite as the substrate has been computed using ST ABCAL and the computational results are compared to experimental data. Absorbents other than ferrihydrite such as aluminum hydroxide are also discussed.

Jan 1, 2005

By John R. Hayes, Kebbi A. Hughes, John Rowson, Peter E. R. Blanchard, Jeremiah C. Beam, Andrew P. Grosvenor, Arthur Situm

Uranium ore bodies contain elements within mineral phases that need to be disposed of responsibly. Solid waste can be placed in a tailings management facility (TMF) to contain the waste elements and limit interactions with the environment. It is important to understand how the chemistry of the tailings evolves throughout the lifetime of the operations that feed the TMF and after the site has been decommissioned. The objective of our collaboration with Orano Canada was to study how the tailings from the TMF located at McClean Lake, Saskatchewan change over time. This manuscript discusses our use of X-ray absorption spectroscopy (XAS) and X-ray microprobe to study the fate of Mo and Ca in the tailings. Mo is considered an element of concern (EOC) and it is necessary to determine if a stable solid Mo-bearing species forms. Thermodynamic modeling suggested that aqueous Mo would precipitate over time as powellite (CaMoO4). Comparing Mo K-edge XAS spectra from the solid tailings to the aqueous Mo concentration in the pore water showed that powellite did form and that this did result in a decrease in the aqueous Mo concentration over time. Further, it has been proposed that Ca2+(aq) can react with bicarbonate ions in the pore water and precipitate as calcium carbonate (e.g., CaCO3). This reaction would limit the aqueous bicarbonate present in the tailings that could react with uranyl ions to form soluble uranyl-carbonate complexes. We have identified several trace Ca-bearing species, including carbonates, in the tailings using XAS and X-ray microprobe.

Jan 1, 2020

By Raynald Vézina, Richard Leclerc, Jean Boissonnault, Louis P. Gignac, Gérald Veillette

Since mid-1989, Cambior has increased its producing gold mines from four to six, having acquired the Chima Mine and brought the Silidor Mine onstream. In June 1990, the company announced that the Mouska project would also be put into production. Gold production reached almost 190 000 ounces in 1989 and is expected to exceed 220 000 ounces this year. Cambior has also a non-gold operation with an interest of 50% in the Niobec Mine and has recently signed an option agreement in the development of the Lac Knife graphite deposit in northeastern Quebec. During the past year, the company has extended its exploration activities to the United States and Indonesia, and now has interests in nearly 80 properties. Last May, Cambior signed an option agreement with Golden Star for a gold deposit in Guyana, the OMAI Project, containing at least 2 000 000 ounces of gold in situ.

Jan 1, 1990