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By Paul L. Broughton

"IntroductionThe coal deposits, all of lignite rank, of economic interest in Saskatchewan are associated with the Ravenscrag Formation (Paleocene). Several Cretaceous formations have less significant lignite accumulations (Broughton, Irvine and W'hitaker, 1974). The Swan River Group (lower Cretaceous) and Judith River Formation (upper Cretaceous) have the only coalbearing strata in the shallow subsurface of central Saskatchewan. The Swan River Group coalfield is relatively small and underlies only 15 sq km of the surface approximately 40 km south of La Ronge, Saskatchewan. An estimated 36 billion short tons are within 45 m of the surface. No reserve estimates are known to have been calculated for the coal-bearing Judith River Formation exposed at the surface in the vicinity of the South Saskatchewan River valley in west-central Saskatchewan. Although no coalfields have been delineated, lignite beds up to 1.8 m thick have been intersected in test holes. The coal-bearing upper Cretaceous and lower Tertiary strata of the northern Williston Basin extends the full width of southern Saskatchewan for 650 km, and from the United States border 120 km north to 50° latitude (Fig. 1). Only the coalfields of the Ravenscrag Formation, because of their economic interest, will be considered further. There are four major coalfields. They are, from east to west: Estevan, Willow Bunch, Wood Mountain and Shaunavon (Cypress) coalfields. Cumulative lignite seam thickness for each basin is 10 -15 m (Figs. 2 and 3). The origin of each coal basin, resource calculations, seam stratigraphy, and mining activity are discussed. Regional Setting The Williston Basin is an ellipsoidal depression in the Precambrian basement, centered in western North Dakota and marginal to the exposed craton of northern Saskatchewan and central Manitoba (Fig. 1). The sediments of the basin range from Cambrian to Pleistocene in age and have a maximum known thickness of 4614 min western North Dakota. A maximum of 3200 m is recorded in southern Saskatchewan. Most structural deformation is late Cretaceous to early Tertiary (Paleocene) in age, coinciding with the Laramide Orogeny. The pre-Laramide Williston Basin, with a depocenter near Williston, North Dakota, began developing during the middle Ordovician, or possibly earlier."

Jan 1, 1985

By J. Visman

"Cyclone separators of different design are being used in increasing numbers in the coal industry of today. One recent addition, the Compound Water Cyclone, is finding application in the North American and Australian coal fields for the beneficiation of coking coals and for the reduction of sulphur and ash in steam coals. In this paper, the combination of specific-gravity separation, thickening, classification and water recovery are discussed. All of these operations can now be accomplished by means of cyclones that are effectively combined in circuits of compact design. In the layout of such integrated plants, three main sections are distinguished, namely: a Main Section for cleaning the plus-28-mesh fractions; an Effluent-Beneficiation Section for treating the minus-28-mesh fractions; and a Water-Recovery Section, where the wash water is reconditioned, and the fine solids are removed in a semi-solid state as slugs or pellets. Depending on the nature of the coal and the specifications of the purchaser, water-cyclone circuits can be flexibly combined with HM Cyclones and froth flotation, as well as with ancillary equipment for dewatering and drying."

Jan 1, 1968

"The Val d'Or Division now comprises the Lucien C. Beliveau Mine and Concentrator (formerly the Pascalis, described below) and the Chimo Mine. Cambior acquired an initial 50% interest in the Chimo Mine in May 1989 and the remaining 50% in April 1990. Cambior's share of 1989 production was 2121 ounces; the company expects to net 23 750 ounces from Chimo in 1990. Pascalis MineUPDATERenamed the Lucien C. Beliveau Mine at its official inauguration in September 1989, the mine is exceeding forecasts, producing over 11 500 ounces of gold in the first half of 1990. Cambior expects 1990 production to total 34 000 ounces.IntroductionThe Pascalis Mine is located 16 miles east o f Val d'Or, Quebec, and is accessible by a three mile gravel road off highway 117 (Fig. I).The property is wholly owned by Cambior.The Pascalis gold deposit consists o f a sub-vertical diorite dyke 1000 ft long by 30 ft wide containing quartz and tourmaline veins with inclusions of pyrite and native gold . Three vein systems ca n be seen in the deposit , the most important being tensile veins oriented at a right angle to the direction of the dyke and inclined at 40 degrees. These overlapping veins vary in thickness from 4 in. to 40 in. and occur at intervals of six to ten ft. The deposit is, therefore, very difficult to evaluate; a complete evaluation would require drifts over the whole width of the dyke combined with relatively short drill holes (Fig . 2)."

Jan 1, 1990

By Fazel G. Jahromi, Ahmad Ghahreman

"Atmospheric leaching of arsenical sulfide concentrates, and especially enargite leaching, is one of the major challenges within the current hydrometallurgy research area. One of the recent processes developed for sulfide ore treatment is atmospheric leaching in the presence of AF 5, a novel carbon based catalyst, in chloride media. The quantification of different ion concentrations during enargite and chalcopyrite leaching in the presence of AF 5 were measured and the copper recovery rates of 97% and 96% were achieved. The objective of this study is to shed light on the leaching mechanism of the sulfide minerals. Based on the speciation of iron and copper by different titration methods, the AF 5 catalyst first reduced ferric and cupric ions and then oxidized ferrous, cuprous and arsenite ions. The oxidation behavior of the catalyst enhanced the leaching results. The AF 5 catalyst also caused in situ precipitation of scorodite in leaching experiment. The speciation of ions in the chloride media were simulated by Phreeqc software and the dominant species in the leaching solution were determined.INTRODUCTION The hydrometallurgy of copper has been used for several decades and is still under development for more complex copper sulfide minerals due to their refractory nature. Most of the world copper reserves are in the form of chalcopyrite; and enargite is known as a major contaminant. Pyrometallurgical processing of enargite is problematic due to arsenic release and tight environmental regulations (Peacey, Gupta, and Ford n.d.). On the other hand, lower recoveries in the hydrometallurgical processes make most of these processes impractical. Several leaching processes have been developed for the leaching of copper sulfide minerals. Some of the common treatment methods for copper sulfide minerals are pressure oxidation leaching (POX), CESL, Activox, Albion process, atmospheric ferric sulfate leaching, Dynatec, Galvanox, and Hydro copper process (Barr, Defreyne, and Mayhew 2005; Conner and Anderson 2013; D.G. Dixon, Mayne, and Baxter 2008; Hyvärinen and Hämäläinen 2005; Palmer and Johnson 2005; Rohner, Bartsch, and Ngoviky 2012). Generally it is not viable to dissolve copper sulfide minerals at ambient pressure in mild acidic media and dissolution of these refractory minerals requires harsh conditions in the presence of oxidant materials (Biswas and Davenport 2002). Ferric ions have been used as an oxidant in different media in copper sulfide leaching processes. U. S. Bureau of Mines’ Reno Metallurgy Research Center in 1969 (Haver and Wong 1971) investigated ferric chloride leaching of chalcopyrite. Dutrizac and Macdonald (1972) studied ferric sulfate leaching of enargite. Based on this study, 50% of the copper was recovered at 80-85 ºC after 7 days of leaching. Cupric ions can also be used as an oxidant. Parker, Paul, and Power (1981) stated that cupric/cuprous couples are more effective than ferric/ferrous couples in chloride media because they are rapid and reversible. The Hydro Copper process leaches copper sulfide minerals in chloride solution catalyzed by cupric ions. In this process, copper dissolves as cuprous ions in presence of cupric ions (about 10 g/L) (Hyvärinen and Hämäläinen 2005)."

Jan 1, 2017

By A. E. Gran

"QIT -Fer et Titane Inc. currently produces and markets four main products: a titania slag named SORELSLAG for the white pigment production, a high purity pig iron known as SOREL-METAL mainly used in the ductile iron casting industry, an ilmenite ore for blast furnace applications called SORELFLUX and high quality steel billets SORELSTEEL employed in the wire rod fabrication. Moreover , QIT also manufactures high quality iron and steel powders labeled ATOMET for the powder metallurgy industry through its wholly owned affiliate. Quebec Metal Powders Limited. The company operates. rock ilmenite mine near Havre St. Pierre and produces its slag and ferrous products from its metallurgical installations located in the Sorel/Tracy region. QIT. born in 1948 from a joint-venture between Kennecott Copper Corporation and New Jersey Zinc Company, was acquired from BP Minerals by RTZ Corporation PLC in 1989 and remains its wholly owned subsidiary ever since.lImenite is a mineral rich in both titanium and iron oxides. QIT's proprietary mineral enrichment and electric smelting processes permit the concentration of the ilmenite ore and the separation of its main constituents to produce a 80% TiO2, slag and a high purity molten iron which is further transformed into iron ingots (pigs), steel billets, iron and steel powders.QIT's ilmenite deposit is located in the Lake TIo-A1Iard area, 43 km inIand from Havre St. Pierre, a community on the north shore of the St. Lawrence River some 960 km from Montreal. The orebody, covering some 542 000 m2, consists primarily of coarse-grained ilmenite (FeO.TiO2) with disseminated fine lenses of hematite (Fe2O3). The worthless mineral (gangue) associated with ilmenite is mainly anorthosite, a complex silicate. QITs mining operations are carried out using conventional open pit methods in a 500 m by 600 m horse-shoe shaped mine with nine benches developed. Primary blasting is performed on a weekly basis during the mining season. Blasted ore is trucked to the crushing station to be broken down to 15 cm and 7.5 cm sizes, respectively, by means of a primary jaw crusher and a secondary cone crusher. Minus 7.S cm ilmenite is then loaded into hopper cars for the 43 km trip to the Havre St. Pierre terminal where it is stockpiled and reclaimed by under-ground conveyor chutes to a ship loading tower at the dock. The crushed ore is shipped to QIT's smelter located in Sorel in 40 000 tonne carriers from April to December."

Jan 1, 1995

By S. Mostaghel, Fariba Azgomi, Steven Goodman, M. Oliazadeh

"It is known that copper loss to the slag phase can be in the forms of chemical dissolution and mechanical entrainment. The contribution of each mechanism to the total Cu-loss depends on different parameters and may vary significantly. To reduce emissions to the atmosphere and to shorten the converting cycle, most industrial processes are aiming at production of high matte grades. Increased oxygen-to-sulfur potential, required by these processes, results in a highly oxidized slag, which in turn leads to an increased concentration of the chemically dissolved copper in the slag phase. Hence, slag cleaning processes are becoming increasingly important for economic viability of the smelting operations. Hydrometallurgical, pyrometallurgical, and mineral processing routes have been used for copper recovery from slag. The current article reviews a trade-off study evaluating two of the commonly used methods (namely flotation and electric slag cleaning furnace) by comparing the technical pros and cons, operability/maintenance requirements, and capital/operating costs of the operations.INTRODUCTIONLarge volumes of smelter and converter slags are produced by copper smelters around the world. It is estimated that for production of each ton of metal 2.2 tons of slag is produced (Gorai, Jana, & Premchand, 2003). Considering the current pressure on the mining and metals industry for “zero-waste, sustainable and environmentally friendly” extraction of metals, it is absolutely essential for metal producers to improve their efficiencies in order to remain competitive. To meet these objectives, almost all metal producers, from steelmaking plants, ferroalloys, base and precious metals producers, are trying to reduce their metal losses to the slag phase. In particular, copper producers are aiming to produce higher matte grades in their smelting furnaces to reduce the converting time and improve their overall throughput. Copper smelters need to minimize their copper/precious metal losses to the slag phase before final landfilling/use of slag. The current article, therefore, briefly reviews the copper loss to the slag phase, methods of metal recovery from the slag and then presents a trade-off study conducted for a green field flash smelter of the sulfide concentrates. A comparison was made between two of the major process routes for metal recovery from slag, namely slag cleaning furnace and flotation."

Jan 1, 2016

By S. Dallaire

With the attainment of high temperatures it becomes possible to process any kind of material (particularly ceramics) in their liquid state. In the plasma spraying process, the material to be sprayed is rapidly heated until it is molten and is propelled by high velocity gases onto a surface where it adheres, to give protective coatings for a wide range of applications. The method could be considered as one of the most versatile and rapid to build up thick deposits (of plastics, metals, ceramics, cermets) and also free-standing artifacts for particular requirements without resorting to lengthy forming and sintering studies. Although plasma spraying is at the production stage in industry, advanced processes have also been developed for economically producing a wide range of new materials. This paper illustrates the benefits of the process and evaluates the challenges it represents.

Jan 1, 1987

By Ann Bigué

Outline of Presentation 1. Impacts and Benefits Agreements Defined 2. Elements that determine the content of an IBA: ? the nature of the project ? the identity of Aboriginal communities affected by the project ? the legal environment 3. Content of Impacts and Benefits Agreements Impacts and Benefits Agreements Defined Have emerged in response to effects of major mining projects located on or close to Aboriginal lands and close to Aboriginal communities Are negotiated between the mining project proponent and one or more Aboriginal groups May include government May be known under other names

May 1, 2004

By T. V. Simpkinson

Abstract A brief history of the electric arc furnace process of steel-making is given. The greater relative importance of this method of steel manufacture to the Canadian steel industry, as compared with its importance in the steel industry of the United States, is shown. The scope of the process is outlined and brief mention is made of the difficulty of obtaining melting stock low in alloy content. The physical chemistry of steel-making is discussed at length in simple terms, with emphasis on oxidation, de-oxidation, and the role of hydrogen. Carbide-type and silicon-type slags are described and the particular usefulness of each is outlined. The importance of various factors in the melting practice is evaluated on the basis of practical experience. Introduction Although electric furnace steels constitute only a small portion of the total weight of steel used in industrial operations, their importance is relatively much greater than is indicated by comparative tonnage figures. Tool steels, which are vital to all industry, are made almost exclusively by the basic electric arc furnace process, as are stainless steels, valve steels, and the higher alloy types of the class usually referred to as "alloy steels'. For many applications where steel other than electric furnace quality is often used, and when first cost is secondary to performance in service, the extra steel cost of electric furnace quality material is usually returned with interest by consistently longer service life. The electric furnace is pre-eminent in the quality alloy steel field because of the control that may be exercised over conditions of oxidation, de-oxidation, and temperature, the fundamental operations in steel making.

Jan 1, 1948

By Wm. T. Bray

SYNOPSIS Canadian Refractories, Limited, produce a wide range of basic refractories. The chief raw material use in their manufacture is the magnesite which is mined, and beneficiated in a heavy media separation plant, at Kilmar, Que. This paper describes the underground operation and the plant and explains how the gravity separation of light, siliceous gangue from the ore has changed the mining practice, increased the ore reserves, and improved the chemical uniformity of the crushed ore. HISTORY REFRACTORIES are essential in the production of steel and base metals and in other high-temperature processes. Basic refractories, chiefly composed of magnesia which is obtained by burning magnesite, are used to line and repair basic furnaces. When World War I cut? off the importation of Austrian magnesite, upon which North American industry had depended, domestic sources bad to be found. In Quebec, work was begun on deposits of magnesite at Kilmar, half way between Ottawa and Montreal and about ten miles north of the Ottawa river. By the end of the war substantial tonnages were being quarried and calcined, but, when Austrian magnesite again became available, the industry declined rapidly. In 1925, the National Research Council, in co-operation with the Federal Department of Mines, began an investigation of the industry's technical problems. The result of this research work, which was taken over fully by the Company in 1943 and is actively continued, is that the single product of the early 1920's has been supplemented by more than forty specialized products serving the metallurgical and chemical industries across Canada and in more than thirty other countries.

Jan 1, 1951

By A. J. Brown

This paper presents an economic evaluation of resin ion exchange and solvent extraction for the purification and concentration of uraniferous solutions derived from sulphuric acid leaching operations. Capital and operating costs are related to the uranium tenors of pregnant solutions. The conclusions drawn herein apply only to cases where resin and liquid ion exchange are technically feasible process alternatives. It is shown that solvent extraction is economically favoured for pregnant solutions at tenors greater than 0.90 gpl U3O8. Pregnant solutions with tenors below 0.35 gpl U3O8 are best treated by resin ion exchange. Between these concentrations, the economics are marginal and the favoured process is indistinguishable within the limits of accuracy of this study.

Jan 1, 1979

By A. Warczok, T. A. Utigard

"Slags from smelting of copper concentrates contains from 1 to 15% of copper. Copper is present in the form of copper or copper matte inclusions of size from 2 to 1000 micro, and as dissolved cuprous oxide. Removal of the copper requires the slag reduction, primarily reduction of magnetite and co-reduction of cuprous oxide. Thus, the kinetics of the slag reduction play an important role in copper recovery. Instantaneously, at the contact of carbon and a slag the gaseous film is formed. The magnetite and cuprous oxide reduction is going through a gaseous film, separating the slag and carbon of a coke or electrodes. The thickness of a gaseous film grows to a critical value and gas bubbles, containing CO and CO2, are created and rise up in the slag. Results of measurements of kinetic of the slag reduction with graphite showed high value of activation energy, close to the value of activation energy of Boudouard reaction. Strong temperature dependence of the reaction rate points out the thermal instability of the reacting system. It was found that the slowest process in the reduction stages determines the loop of CO and CO2 transfer and magnetite diffusion to the slag/gas film boundary. Strongly endothermic Boudouard reaction seems to cause thermal instability on the reaction surface. So, heat transfer to the reaction surface is very important. Due to low thermal conductivity of a slag the convection dominates in the heat transfer. So, any slag stirring accelerates the rate of reduction and coalescence of metallic copper or copper matte inclusions."

Jan 1, 2015

By F. C. Robles Hernandez

This paper presents the results of the electromagnetic semi-solid treatment of the 319 aluminum foundry alloy, Various levels of structure modification were achieved controlling the AC current used to create the Electromagnetic Field, thus manipulating the intensity of the field, The level of grain refinement, partial modification of the Al-Si eutectic, as well as cellular dendrites were observed, A quantitative analysis of the structure was performed using Image Analysis (IA) techniques. In addition a novel Thermal Analysis methodology was developed for the on-line determination of the microstructure modification level.

Jan 1, 2004

By C. Samuelsson, H. Ahmed, B Björkman, A. Andersson

The cost of raw material and energy is a continuing driving force towards working with increasing the recycling of ore based steelmaking residues. In Sweden no on-site sinter plants are operated at the integrated steelworks. Instead, selected residues from the plant are incorporated in a cold bonded briquette product which is recycled to the process via the blast furnace (BF). Since the BF sludge is the major bleed of zinc out of the furnace it is required to be de-zinced prior to recycling in the briquette product. In the present work landfilled BF sludge has been characterized with respect to chemical composition, particle size distribution, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The sludge was also subjected to laboratory scale hydrocyclone trials aiming at reducing the zinc content making the sludge viable for recycling. The results suggested that the sludge had been agglomerated prior to the characterization and hydrocyclone treatment. The zinc removal using the hydrocyclone was discussed.

Jan 1, 2015

By D. V. Dorling, J. T. Bowker, J. A. Gianetto

Over the last few years, interest in the development and construction of large diameter, high pressure pipelines from the Mackenzie Delta in northern Canada and Alaska's North Slope has steadily increased as a result of the projected decline in recoverable natural gas from existing reserves in western Canada. The success of such enormous pipeline projects, which will require utilization of a strain-based design approach, is largely based on successful application of high strength line pipe steels, such as X80 and X100. To fully realize the economic benefits of high strength steels, welding processes and procedures must be developed to ensure that the requirements for high strength and good low temperature toughness are confidently obtainable in field girth welds used in the construction of such pipelines. This study aims to provide a better understanding of the factors that control weld metal strength and toughness for a series of mechanized X100 girth welds produced using a range of narrow-gap gas-metal arc welding procedures. The attainment of high yield strength (> 810 MPa) is considered to be an important target to ensure overmatching strength relative to the longitudinal property distribution of X100 line pipe steel. Some factors that have been considered in this evaluation include influences of gas-metal arc welding process variants (single and multi-wire) and changes in welding procedure specifications, including joint preparation. Key components of this work relate to the reliable measurement of weld metal strength variation through-thickness and as a function of position around the circumference of a given girth weld.

Jan 1, 2005

By R. C. Wallace

In the early explorations of the Northwest, the search for minerals played a not inconsiderable part. The first episode had its disillusioning sequel. Sir Martin Frobisher, in 1576, sailed up that bay in Baffin land now known as Frobisher bay, thinking that he had the coast of Asia on his right hand. He brought back from this expedition a piece of 'black earth' from Hall island, from which an alchemist by coaxing nature, or his own conscience, obtained gold. A second expedition of three ships was fitted out in 1577, and a third of fifteen ships in 1578. The ships were loaded with this 'black earth', which on subsequent investigation was found to be worthless, and interest in minerals for the time being ceased. In 1612 Hall and Baffin went in search of a gold mine near the Arctic circle on the west coast of Greenland, reported to be worked by the Danes. They found old workings, but no ore. To come nearer the Hudson Bay area, it is noteworthy that the charter granted by Charles II to the Hudson Bay Company in 1670, as a result of the explorations of Radisson and Groseillers, was given "-in consideration for their having at their own cost and charges undertaken an expedition to Hudson bay in the northeast parts of America, for the discovery of a new passage to the South sea, and for the finding of some trade for furs, minerals and other considerable commodities, and of their already having made by their undertakings such discoveries as did encourage them to proceed farther in pursuance of the said design, by means whereof there might probably arise great advantage to the King and his Kingdom - ".

Jan 1, 1925

By A. Idegami, M. Imamura, S. Heguri, Y. Ozaki

"Nickel powder can be produced by the reduction of a nickel ammine complex solution by hydrogen at high temperature and pressure. To minimize the deposition of fine nickel on the surface of the reactor and other equipment, seed crystals are added to the initial solution to promote nucleation of the nickel powder. Such seed crystals catalyze the precipitation of the nickel particles on the surface of the seed and enhance grain growth. In this study, nickel nuclei were precipitated by the addition of a polymer to the nickel ammine complex solution, resulting in the production of nickel powder. Thus, we herein propose a model that explains the effect of the polymer in the precipitation of nickel nuclei.INTRODUCTIONNickel powder is commonly produced via a hydrometallurgical process from the hydrogen reduction of a solution containing a nickel ammine complex at high temperatures and pressures, and this process was commercialized in the 1950s by Sherritt Gordon (Sherritt International, Canada, Benson & Colvin,1973; The Staff, Research and Development Division, Sherritt Gordon Mines, Ltd., 1958).In the above transformation, upon the injection of hydrogen gas into the solution, nickel is reduced as outlined in Equation(1), ultimately resulting in the production of nickel powder.Ni(NH3)nSO4+ H2?Ni+ (NH4)2SO4+ (n-2)NH3(n:2–6)(1)In this process, seed crystals are added to the reactor to suppress the precipitation of fine nickel (scaling) and to enhance nickel reduction (Benson & Colvin, 1973; Mackiw, Lin & Kunda, 1957). More specifically, iron sulfate and a small amount of dispersant polymer are added, which leads to the formation of nuclei. Upon subsequent hydrogen reduction, the reduced nickel can then be deposited on the nuclei, allowing nickel particle growth to take place. However, this results in iron contamination in the final nickel product, and so the use of pure nickel as a seed crystal is desirable to produce high quality nickel powders."

Jan 1, 2017

By D. M. Rippley

THE St. Lawrence Seaway Project ranks with the greatest engineering undertakings of all time. A summary of major materials going into the construction of this project, shown in Table I, will assist in an appreciation -of this fact. These data relate to Seaway construction only, and it should be remembered that two large-scale power projects are in the construction stage on the St. Lawrence river concurrently with construction of the Seaway. A project of such magnitude as the Seaway would attract widespread interest even if it were being constructed in a remote area. The fact that it is located in a heavily populated and developed section of both Canada and the United States has done much to enhance this interest, and in many ways complicates the problems confronting the engineer in the design and construction phases. Many consider the St. Lawrence Seaway to be a new idea that has developed within the past decade - such is far from the fact, because the St. Lawrence River canal systems have existed for more than a century, and the Seaway Project is but a new, larger, and more efficient version of a continually expanding facility.

Jan 1, 1957

By Robert Cameron, Colin Ashton, John MacNeil, Leo Piciacchia

"The in pit dam construction and utilities relocation, known as the East Mine Corridor Relocation (EMCR) project, was developed to extend the life of the east side of the Base Mine pit by two veal's. This will result in the recovery of an additional 80 million barrels of oil and delay expenditures associated with the opening of the North Mine by two years. To accomplish this, a large in pit earth structure was required to provide a new embankment foundation for relocating a public highway, four powerlines, a natural gas back-up pipeline, a substation, and a conveyor train. This structure would also he required as a temporary dam 10 contain mature fine tails on the west side until mining is completed in the east mine corridor area, that will then be filled with fluid.The in pit dam, known as The Highway Berm, is 2.5 km long, 63 m high and has 42 million m3 of engineered soil added to the already existing end-dumped soil volumes. To complete the design and construction of a structure of this magnitude, in the very short time frame of two-and-a-half years, presented many new challenges. The main challenges faced were: designing while construction was ongoing; designing without the use of clay cores or sand filters; using relatively non-select overburden material; proper dewatering and base preparation; changing from construction of 50 m high spoil piles to a high specification construction operation; compacting lifts with heavy haulers; constructing during the winter; and monitoring movement of the structure with satellites."

Jan 1, 1995

By B. N. Church, R. H. Seraphim, J. T. Shearer

"The Lexington-Lone Star CU-Au deposits straddle the Canada U. S.A. border, south of Greenwood, British Columbia. This 3 km long linear porphyry system occurs in a northeast dipping belt of sheared quartz porphyry and serpentinite. The best grades of mineralization occur in three principal bodies known as the Pit zone, the Northwest zone and the Lexington Main zone. The Pit zone at the Lone Star mine is the largest of the mineralized bodies and consists of fracture fillings and disseminations of pyrite, chalcopyrite and minor molybdenite, hosted by the Lexington quartz porphyry. The Northwest zone, discovered by drilling through overburden near the 49th Parallel, consists of pyrite-chalcopyrite-gold mineralization in the quartz porphyry and the footwall serpentinite. The Lexington Main zone has the highest grade of gold and occurs near the footwall of the quartz porphyry with the mineralogy and setting similar to the Northwest zone. Alteration of the host quartz porphyry is mostly sericitic and chloritic; alteration in the adjacent serpentinite is mostly talc and carbonates.A weighted average of the drill-indicated reserves is 19.5 million tonnes grading 0.56% CU and 0.55 gl t Au.IntroductionThis paper describes copper-gold mineralization associated with the Lexington quartz porphyry in the Greenwood mining camp of south-central British Columbia and adjacent parts of Washington State (Fig. 1).Access to the property is mainly by a network of farm, logging and old mining roads to the U.S. border, 10 km south of Greenwood, British Columbia."

Jan 1, 1995