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By Charles Graham

It is the general belief that the coal deposits on Vancouver Island are extremely large, and easily available. Indeed, they are frequently described by prominent public men and by writers in the press as "illimitable" and "inexhaustible." It is well that the facts that have been established as a result of seventy years of surface prospecting, underground operations and extensive diamond-drilling in this coalfield should be disclosed. HISTORY The presence of coal on the coast of British Columbia was first made known by Dr. W. F. Tolmie in 183 5. This coal was brought to him by Indians from the north-east coast of Vancouver Island, probably from Suquash. In 1850 the existence of coal at Nanaimo was announced by Mr. ]. W. MacKay. Development was started in 1852, and coal was shipped before the close of 185 3. The first operations were carried on by the Hudson's Bay Company, who operated the mines until 1861, when they sold them to the Vancouver Coal Mining and Land Company. Practically all of the operations in the immediate vicinity of Nanaimo have been carried on by this Company and its successors. In 1869, Mr. Robert Dunsmuir discovered coal about five miles north-west of Nanaimo, at Wellington. The Welling-ton Colliery Company was organized, and began to produce coal from the Wellington mines in 1871, the coal being shipped from Departure bay. This colliery was a large producer for several years, but was finally closed in 1900.

Jan 1, 1924

By D. Stone

"The Beal Mountain mine near Anaconda, Montana, is an interesting case history of a mine that has continued operations despite several large pit wall failures over a period of approximately 10 years. The largest event involved some 3.9 million tons of rock that has moved steadily at a rate of about 0.05 ft/day since 1992. This paper documents the geotechnical instrumentation and monitoring programs implemented at Beal to provide the company with a comfortable baseline that supported ongoing operations. The success and failure of a variety of stabilization measures will be discussed, along with typical instrumentation responses for several significant events. The success of Beal Mountain serves as a good model for mines faced with serious geotechnical challenges."

Jan 1, 2002

By J. A. Brusset

THE Greenhill mine of West Canadian Collieries, Limited, is situated at Blairmore, Alberta, and produces 2,500 tons per day of bituminous coal. On Monday, October 25th, 1943, smoke was discovered by a party of firebosses on their regular weekly inspection of air-ways. Probably the fire had been smouldering for several days but, as it had started on the outcrop at the top of an old raise filled with dirt, only a small quantity of smoke could filter through, and the plume of mist that crowns the fan at that season had prevented the fan-man from noticing it. This raise is only about 200 feet from the fan, and is 70 feet long between the fan-drift and the outcrop. It was impossible to prove the origin of the fire, as it had probably started several days before it was discovered, but it is possible that a careless smoker may have thrown a match into the opening at the outcrop, and that the old, dry timber had caught fire. The airways are in No. 2 seam, a bituminous seam 18 to 25 feet thick surmounted by shales and sandstones. Only 45 feet vertically above it is No. 1 seam, 12 feet thick, overlain by a strong conglomerate. In that vicinity, No. 1 seam had been worked out about ten years ago and the strata between the two seams are undoubtedly fissured. The pitch of both seams is 43 degrees.

Jan 1, 1945

By H. Sato, Y. Sato, T. Ooishi, K. Sakamoto

"Sumitomo Metal Mining Co., Ltd.(SMM)'s Niihama Nickel Refinery(NNR) produces high quality Nickel cathode, Cobaltcathode and other by-products using hydrometallurgical refining process called “MCLE”(Matte Chlorine Leach and Electro-Winning). In 2005,NNR started to use nickel and cobalt mixed sulfide (MS) produced by one of the SMM’s subsidiaries Coral Bay Nickel Corporation(CBNC)’s HPAL plant in Philippines, although its main and the only raw material until then was nickel matte. With start-up of the second HPAL plant at Taganito in 2013, NNR expanded its production capacity of nickel cathode from 41,000 to 65,000 tpa and finally achieved its target in 2015 by producing 65,980 tpa. SMM developed the technologies to improve poor reactivity of MS and installed new facilities to cope with increased Cobalt and Sulfur production at that time. This paper describes the technical approach to increase MS treatment with high efficiency.INTRODUCTIONThe Sumitomo Metal Mining Co., Ltd.(SMM)Niihama Nickel Refinery(NNR) produces Nickel cathode, Cobalt cathode and other by-products using Matte Chlorine Leach and Electro-Winning (MCLE) process technology. SMM uses nickel matte and nickel & cobalt mixed sulfide (MS) as raw materials for the MCLE process. Table 1 shows typical composition of these raw materials. Nickel matte had been only raw material until 2005, and with start-up of Coral Bay Nickel Corporation (CBNC) operation in the Republic of the Philippines, MS became major part of it. In 2009, when CBNC doubled its production capacity, NNR also expanded its plant capacity of electrolytic nickel from 36ktpa to 41ktpa, keeping an eye on the possibility of 65ktpa with oncoming SMM’s second HPAL in Philippines. Poor reactivity of MS was the prime concern at that time because our intention was to increase production with MS. Nickel extraction rate deteriorated with increasing usage ratio of MS in raw materials. To keep high nickel extraction rate under high ratio of MS, NNR developed a new leaching technology. Another concern arising from treatment of MS was Cobalt and Sulfur contents that are much more than those of nickel matte as shown in Table 1.NNR introduced new technology of solvent extraction process as to Co/Ni separation process in order to keep cost competitiveness instead of the conventional cobalt oxidation–neutralizing method. As to sulfur products, new sulfur productive facility was installed to improve the exposure to sulfur dust and the hot working conditions for workers. As a result of process development and installation of new facilities against the problem with MSusage,65 ktpa production was achieved in 2015."

Jan 1, 2017

By J. R. Kish, J. Dabrowski

"The susceptibility to intergranular corrosion modes is a major technical issue preventing widespread utilization of higher strength welded AA7xxx extruded beam profiles, in the peak-aged T6 condition, in automotive bumper assemblies. A study was undertaken to evaluate the relative exfoliation corrosion resistance (ASTM G85-A2) as a function of joint design parameters, namely the base alloy composition, heat-treated condition and beam orientation after exposure to a cyclic acidified salt spray test. This paper documents the major findings extracted from this study.INTRODUCTIONBumper systems play a predominant role in the passive safety of an automobile, since they are one of the main structures for absorbing the collision energy in the event of an automobile crash. Heattreatable AA6xxx-series (Al-Mg-Si) and AA7xxx-series (Al-Zn-Mg) Al alloys, with relatively high strength, toughness, energy absorption, weldability and formability, make it possible to design costcompetitive bumper systems to crush in a controlled fashion. In this context, Cu-lean AA7xxx extrusions, such as AA7003 and AA7108, which exhibit higher strength than AA6xxx extrusion, such as AA6082, represent an attractive light weight material from which to fabricate bumper assemblies (Clausen et al., 2000; Pedersen et al., 2008; Chen et al., 2009).Arc welding is a key joining process for AA7xxx alloys within the transportation industry. A major technological issue preventing widespread utilization of arc-welded AA7xxx joints is the susceptibility to severe localized corrosion (Kent, 1970, Reboul et al., 1985; Holroyd et al., 1987). It generally occurs as exfoliation corrosion within a heat affected zone (HAZ) a few millimeters from the weld bead, or a type of stress corrosion cracking (weld-toe cracking), which initiates at the weld toe and propagates into the interfacial region between the weld bead and the HAZ (so called “white zone”). In addition to the micro-galvanic cell activity induced by the intermetallic compound constituent and strengthening particles present, there is strong evidence that macro-galvanic cell activity between the weld bead and base AA7xxx alloy may be playing a controlling role. Electrochemical profiles taken across fusion welded joints, in cross-section, during exposure to saline solutions suggest that a significant potential difference exists across the AA7xxx arc-welded joint (Shumaker et al., 1967; Grauer and Wiedmer, 1980; Tuck, 1985, Onoro and Ranninger, 1993). These studies consistently show that the HAZ and base alloy are more electronegative with respect to the weld bead (arc-welded with AA5xxx filler wire). Despite this initial important work, the majority of the recent corrosion research effort on welded AA7xxx alloys has focused on the performance of friction stir welds (Lumsden et al., 1999; Wadeson et al., 2006; Hatamleh et al., 2009)."

Jan 1, 2012

By R. D. Brown

The first step in achieving a rationalization of Canada's crazy patch-work quilt of mining taxes and policies was achieved with the release last November of a major federal-provincial report on the taxation of the Canadian mining industry. The Report, prepared by a group of federal and provincial civil servants, sets out a concise and informative discussion of the major taxation and incentive issues facing the mining industry, and puts forward major recommendations for more rational and moderate taxation policies. It will be considered by federal and provincial Finance and Resource Ministers for possible action by the respective governments. The Report was prepared in response to a directive from the federal and provincial First Ministers in February 1978 to review the federal and provincial taxation of the resource areas. Although the Report is more successful in identifying problems rather than concrete solutions, and reflects some continuing differences of opinion between the governments involved, it does represent an important first step in a comprehensive review of our resource tax policies. This article summarizes the Report, which is some sixty pages in length. Although a detailed discussion of it is beyond the scope of this article, the report itself is recommended reading for those concerned about the current state of the Canadian mining industry.

Jan 1, 1979

By T. Holmes

Investigations reveal that the throughput difference between a perfect production day and the average is often on the order of 40%, and that bulk solids handling system deficiencies are the largest (>50%) class of lost opportunities. Root causes for underperformance of elements in material handling systems can often be traced back to the detailed design and even study-stage oversights. To reduce or eliminate bulk solids handling problems in an existing system requires an analysis of troublesome handling equipment – for example, a concentrate transfer chute that experiences plugging, poor flow to the furnace, unacceptable dust generation, and spillage. These problems often lead to significant maintenance costs related to downtime and personnel time. Understanding the cause and cost of flow issues is the first step in troubleshooting the problem. Next, measuring the material’s flow properties is critical to providing design data required to develop a comprehensive scientific solution. In the case of a new installation, the design data is required to properly design the system right first time and prevent flow problems from occurring so that the new equipment works correctly from start-up. This paper highlights the cost of material handling problems and discusses the best approach to evaluate material handling system deficiencies. A case study is given of how Anglo American's operation in Barro Alto Brazil enjoyed a 5-month payback from a bulk solid transfer chute debottleneck project. INTRODUCTION When operating a plant or designing a greenfield or brownfield operation, the intent is to have perfect production days (PPD) each and every day. Money is made by moving material through the plant in a controlled manner to produce the desired product. Mining operations and copper concentration processes are at the most basic level a practice in bulk solids handling (BSH). Unfortunately, many of the project planning steps are overlooked, particularly related to BSH. Investigations reveal that the throughput difference between a PPD and the actual average is often on the order of 40%, and that BSH system deficiencies are the largest (>50%) class of lost opportunities (Wellwood, 2017). Root causes for underperformance of elements in material handling systems can often be traced back to the detailed design and even study-stage oversights. BSH issues are essentially baked into the fabricated plant and left to operations to accept the deficiencies and deal with them for the life of the mine. These deficiencies then become part of the normal operation of the mine and plant.

Jan 1, 2019

By Alexander Smith

"The three principal known mineral deposits of the Taku River area lie in the Tulsequah synclinorium. The axis of this north-south trending structure is along Tulsequah River valley; about 6 miles east of the eastern contact of the Coast Range batholith.The one proven mine of the area, the Polaris-Taku, is on the west side of the valley. It is a gold property, the gold occurring in fine needles of arsenopyrite disseminated in carbonatized volcanics. The mine was originally called the Whitewater, and the adjacent area the Whitewater gold belt. During the years 1937 to 1942 gold having a value of $3,284,000 was produced from 313,500 tons of ore milled."

Jan 1, 1954

By J. J. McDougall

Until quite recently, the coal in the Cape Breton field was won from comparatively thick seams with light cover, and from submarine areas, and the system of mining naturally followed was pillar-and-stall. This sytem permitted of cheap extraction, and enabled production from localities where other methods could not be employed to good advantage. Thus the pillar-and-stall system, applied to conditions as stated, justified its adoption. Our working seams today, however, are practically all under heavy cover, or are moving in that direction, and with this gradual increase in cover came the increased cost of roadway maintenance. At Princess colliery, the system of pillar-and-stall was followed until roof and bottom conditions became such that further operations were unprofitable, and the longwall method was then adopted as an economic necessity. This fact should be borne in mind when operating costs of both systems are being compared. The longwall method is not held as a cure for all difficulties of heavy cover, but through it these difficulties can be overcome with less expense than by pillar-and-stall. The longwall system of mining, strictly speaking, is one by which a seam of coal is totally extracted in one operation. There are, however, many modifications of longwall, and in some cases it is difficult to determine whether certain practices should be classed as longwall or pillar-and-stall, or a combination of both.

Jan 1, 1928

By Ursula M. Franklin

Old iron nails are one of the most common objects which entice the general public to ask questions about the history of metallurgy. There is a lot of history in old nails - history of the manufacturing industry, and social and economic history. Nails, therefore, are fine teaching tools; whether students have to acquire metallurgical skills or explore the structure and properties of wrought iron, whether they want to look into the history of inventions and the development of machinery, studying nails tells a story better than any teacher or any book. I have used this approach often and the following note is based on several student projects, particularly the work of Carmina Herrero and Vicky Marchant. Nails, those essential metallic fasteners, have long been with us. Their size, shape and design is basically a compromise between the makers' ability to control and manipulate material and the demands of the intended application. There were copper and bronze nails in antiquity, but in this paper I want to deal only with iron nails. In Rome, iron nails were common, and Cleere carried out the fine metallographic investigations on a large stock of nails recovered from a Roman fort site in Scotland. Those nails were hand forged; sorting them at the site on the basis of length, shape of head and shape of shank (in cross section) indicated that there seemed to have been some nail standardization. It appears that the Roman smiths used a series of heading dies starting with a 1/s-in. size. Each successive size increased by approximately 1/16-in. The metallographic inspection of the microstructures of the nails showed that the smaller nails were made in the one operation; i.e. both the tapering and the formation were accomplished on the heated rod without reheating. However, in the case of the larger nails, the nail had to be reheated for the tapering after the head had been forged. Most nails were tapered on all four sides of the shank and the shanks were square in cross section; only one group had rounded shanks. Most heads were flat disks, but in one group the heads were pyramids and another group had conic heads. Figure 1 shows the procedure used to produce the pyramidal heads. Obviously, Roman nail making was sophisticated and each nail design was meant for a particular use.

Jan 1, 1999

By Manouchehr Oliazadeh

Talc is used as a gelating, diluting, antimould and softening agent in the pharmaceutical industries. This article reviews efforts made for producing pharmaceutical grade talc from a mine located in the west of Iran, called Masoud Abad. Reaching to the pharmaceutical standards, was the principal goal of the talc beneficiation. Methods such as flotation and leaching were applied to eliminate the impurities. Considering to the negligible Fe content of the ore, the major impurity was calcium carbonate and to some extent dolomite. Depressants used in froth flotation were dextrine, quebraco and sodium silicate. Variation of collectors such as oil petroleum, paraffin, stearic acid were also used. After optimization of the effective parameters, followed by two stages of flotation (rougher and cleaner) acid leaching process was also applied as a complementary step to remove the impurities. CaO impurities in the sample was 11.63% which reduced to 1.03% after two stages of flotation, and finally reached to 0.03% CaO by leaching process. This figure is more lower than the world pharmaceutical standards (i.e. <0.6 % CaO). The highest recovery was 55% at the best conditions. Other impurities (i.e.As, lead, heavy metals ,?) which were at standard levels, confirmed by the authorized health organizations.

May 1, 2001

By R. Glenn Madill

Western Canada is defined, for the purposes of this paper, as that part of the Dominion bounded approximately by the 95th and 141st meridians of longitude and the 49th and 80th parallels of latitude. It is comprised of Manitoba, Saskatchewan, Alberta, British Columbia, Yukon, and that portion of the Northwest Territories lying to the west of the 95th. meridian. The first magnetic observations made in Western Canada were in the interests of navigation by sea. Observations were made by Captain Middleton in Hudson bay at Churchill and York Factory in 1725, and along the Pacific coast by Captain Cook in 1778 and Captain Vancouver in 1792. The first systematic magnetic survey in Western Canada was made between 1819 and 1826 by Sir John Franklin in his widely distributed explorations. It is of interest to find that while the first magnetic declination observations made in Hudson bay and along the Pacific coast were purely in the interests of navigation, the next investigations, which were made in the Western Arctic, included measurements of inclination and force with those of declination. There was a valid reason for this more complete research into the magnetic field as the construction of declination charts depended on the position of the north magnetic pole. Halley promulgated a theory 1683 that " the globe of the Earth may be regarded as one great magnet, having four magnetic poles, two of them near each pole of the equator, and that in those parts of the world which lie near any of those magnetic poles the needle is chiefly governed thereby, the nearest pole being always predominate over the more remote" . The position of a magnetic pole may be defined as a point where the inclination is 90 degrees and the horizontal force zero. It is obvious that the position cannot be&apos; defined by declination observations alone since, for some distance from the magnetic pole, .the horizontal force is too weak to give directive force sufficient to effect the pointing of a compass.

Jan 1, 1948

By G. H. McKay

AT the Eagle mine, near Gilman, Colorado, where the Empire Zinc Company have installed an underground mill, transportation problems were comparatively simple. A railway siding on the Denver and Rio Grande railway is equipped with an unloading dock or platform at the portal of their service incline adit to the mill. This 18-degree incline is approximately 600 feet long from the unloading track to the head of the mill skipway. For the Big Missouri mill, upwards of 2,500 tons of material and equipment had to be trucked from tidewater at Stewart, B.C., a distance of 21 miles to the Big Missouri camp at elevation 2,800. From that point, this freight had to be moved either over or through the Big Missouri ridge, rising to elevation 3,450, to its final location 800 feet from the surface between elevations 2,150 and 2,350. Immediately after leaving the government dock at Stewart, the road crosses the International boundary line into Hyder, Alaska, and then follows a water grade for eleven miles along the lower stretches of the Salmon river. leaving the river, the road climbs for two miles before crossing back into British Columbia territory at Silver Heights, and then continues for another mile and a half to where the Big Missouri road branches off from the main road to the Premier mine. For a distance of four miles from the junction of the roads, the Missouri road is very narrow, with many sharp curves and with irregular up and down pitches and grades up to 25 per cent until it reaches the Summit. From there on, a fairly easy grade leads a mile and a half to the end of the road on Joker Plats. In winter, the last stretch of road is subject to heavy snow drifting, especially through a narrow funnel-shaped gulch, known as &apos;The Gap&apos;, where the snow may pile up to a depth of over twenty feet.

Jan 1, 1938

By Jae-Chun Lee, Sadia Ilyas

We investigate the technical feasibility of bioleaching of metals from low grade sulphidic ore. Experiments were conducted with an adapted consortium of Sulfobacillus thermosulfidooxidans and Thermoplasm acidophilum in batch bioreactors (1.5 L), small columns (10 kg ore load, 8 % S0 sludge) and large columns (80 kg ore load, 12 % S0 sludge). Approximately 83 % Ni, 85 % Cu, 55 % Fe and 81 % Zn was leached out in batch mode while 93 % Ni, 89 % Zn, 81 % Cu and 65 % Fe was leached out in column reactors. Bioleaching potential improved by acid pre-leaching, adaptation of microbial consortium and periodic bleeding of effluents.

Jan 1, 2014

By P. Nelson

Extending the campaign life of the Mitsubishi furnaces at Xstrata Copper&apos;s Kidd Metallurgical Division Copper Smelter has been a major focus of attention for many years. One aspect of this effort is real time monitoring to detect abnormal conditions and safely shut the furnaces down before significant damage occurs. Traditional real time methods of monitoring the integrity of refractory furnaces containing molten metal include alarms on individual temperatures of the refractory or cooling water. The need to set alarm limits which are not exceeded across the range of normal operating conditions leads to a system that only provides a limited warning, if any, before a failure occurs. Integrity monitoring systems that look at many different signals and alarm only changes in the relationships between the signals have been implemented on the smelting and converting furnaces. The systems are based on principle components analysis (PCA) models and implemented with the monitorMV software package. These provide much more sensitive and selective alarms so that changes in integrity are alarmed well in advance of any event. At a critical alarm level, the converting furnace is set to automatically shut down so that operating and technical personnel can review the situation. The configuration of the systems and operating experience with them will be discussed.

Jan 1, 2007

By Michael L. Free, Shukla. Abhijeet

The short-circuiting tendency of a copper electrowinning cell (EW) based on the roughness of cathode deposits was investigated with varying parameters such as Cu concentration, guar concentration, current density, and temperature. A bench scale EW cell was set up to produce copper under conditions similar to industrial Cu EW. In addition, a statistical analysis and finite element analysis were performed to analyze the deposited thickness, surface roughness and maximum feature height. Interaction data for the cathode deposits suggest that current density and Cu concentration together affect the roughness of deposit more than the combined effect of guar and temperature. Model predictions of roughness were similar to experimental values. The predicted time to short-circuiting was similar to the measured time. This study provides an industrial relevant baseline against which new operating parameters can be compared.

Jan 1, 2014

By A. Lee Barrett

"THE COAL INDUSTRY of the United States• and Canada has made great progress in recent years. Coal mining in •the old days represented one of the most arduous tasks for labour and industry, but over the years great progress has been made in reducing the effort required from labour. Also, the tonnage produced per man, the cost of the coal per ton, and the overall safety of the operation, have been greatly improved.Looking back over the past fifty years:, the era can be divided into four principal parts: (a) hand-loading, (b) track mining methods, (c) off-track mining methods, and (d) continuous mining. For many years, all of the coal was won by hand-mining methods. The first forms of mechanization •resembled the move from the horse •and buggy to the automobile. Early track mechanical mining methods were usually adaptations of the direct methods involved in hand-mining, with each improvement directed toward some specific process. A revolutionary development came about with off-track mining methods. The first efforts in this direction were provided by off-track mechanical loading machines, which loaded the cars •on track and differed from conventional track mining methods only in that the loading machines themselves operated on the mine floor. With the advent -of the shuttle car about ten years ago, true off-track mining came into being, and real progress in this direction began to be made.At the present time we •are at the beginning of a new era -.the era of continuous mining. There will be a period of development with some time needed before the system is generally applied throughout the industry, but -already enough •has been done to indicate rather dearly what the future holds in this direction."

Jan 1, 1953

By J. Sliwinski, H. Kikutani, J. Atwood, D. Larimer, J. Pyecha

"The Pogo mine start-up milling targets of 2005 are vastly different than the targets of today. Improvements have been driven by unintentional design oversight, continual circuit optimization or optimization due to changing mineralogy. The more significant process improvements to date have occurred in the gravity, flotation and leach/CIP unit operations. Details of the significant improvements are presented along with the impacts to the process.INTRODUCTION Deposit Overview Pogo mine is located along the Goodpaster River, southeast of Fairbanks, Alaska. This deposit sits in the center of the Tintina Gold Province (Figure 1), a region of similar Intrusion Related Gold deposits in Interior Alaska, the Yukon and British Columbia Canada (McCoy et al., 1997). The Pogo deposit is hosted in a rock sequence of amphibolite-grade gneisses intruded by mid-Cretaceous granitic plutons and dikes, which in turn, were cut by and host the auriferous quartz veins of the Pogo deposit.The Pogo deposit is comprised of three distinct zones of auriferous quartz veins spatially adjacent to each other. These are the Liese Zone, North Zone, and the East Deep Zone. The Liese Zone consists of three stacked, massive quartz veins, designated the L1, L2, and L3. Vein thickness averages 3.0 m, with variations from 0.3–18 m thick. The North Zone mineralization is comprised of four veins with more consistent thickness, between 1 and 1.5 m. The East Deep deposit lies northeast of the Liese Zone ore body. It is separated by a post mineralization, quartz diorite pluton. The East Deep Zone is comprised of two stacked massive quartz veins with similar orientation as the Liese Zone."

Jan 1, 2017

By Y. Héroux, A. Chagnon, M. M. Savard

"Résumé- Le gîte de Pb-Zn de Gays River s&apos;accompagne d&apos;anomalies des propriétés de la matière organique (MO) et des assemblages de minéraux d&apos;argile (AMA). L&apos;association entre la minéralisation, la distribution de la réflectance de la MO et des AMA suggère que ces traceurs peuvent servir à l&apos;exploration des sulfures de métaux de base dans cette région.A l&apos;emplacement du gîte, la réflectance varie considérablement (0,80% à 1,88%), pouvant même afficher une baisse avec l&apos;enfouissement, ce qui est interprété comme une altération chimique de la MO. Les valeurs les plus élevées s&apos;accompagnent localement de quelques textures en mosaïque et délimitent une anomalie thermique au centre sud de la région. Parmi les minéraux des argiles identifiés, l&apos;illite et la chlorite sont terrigènes alors que la smectite, la kaolinite et la corrensite sont authigènes et, à l&apos;instar de l&apos;altération de la MO, résultent des nouveaux équilibres chimiques créés suite à la précipitation des sulfures.Abstract- The Gays River Pb-Zn ore deposit is associated with anomalies defined from the characters of the organic matter (OM) and from the clay minerals assemblages. The relationships be­ tween these anomalies and the mineralization at the mine suggest that these parameters can be used as new guides for the exploration for base-metal sulfides in this area.The vitrinite reflectance (RJ shows a wide range of values (0.8% to 1.88%) and exhibits an anomalous suppressive effect with depth of burial at the mine site, suggesting a chemical alteration of the OM. The highest R, values are associated with mosaic textures and outline a thermal anomaly at the south-center of the studied area. Among the identified clay minerals, illite and chlorite are terrigenous, whereas smectite, kaolinite and corrensite are authigenous and, like the alteration of the OM, are due to the new chemical equilibria resulting from the precipitation of the sulfides."

Jan 1, 1994

By Y. Thibault, G. Deschênes

An open-pit mine, located in Mexico, processes an ore a rate of 4000 tpd, using conventional cyanidation and AYR. A laboratory study was conducted to increase silver extraction and to reduce the concentration of cyanide in leaching. The sample contained 0.41 g/t Au, 125 g/t Ag, 99% gangue minerals, 0.7% pyrite, 0.07% sphalerite, 0.03% chalcocite. Silver was present as acanthite, stromeyerite, silver mercury/halogen, silver with copper in solid solution and jalpaite. The plant conditions (2400 ppm NaCN) produced 90.2% gold extraction (residue at 0.04 g/t Au) and 92.7% silver extraction (leach residue at 9.1 g/t Ag). The CELP (CANMET Enhanced Leaching Process) produced 97.0% silver extraction (residue at 3.8 g/t) and 90.2% gold extraction using 500 ppm NaCN. The incremental gross revenue was estimated at $US7.6 million and the reduction of cyanide costs was $2.9 million per year (79%).

Jan 1, 2011