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By C. G. Anderson

Industrially proven and applied nitrogen species catalyzed (i.e. NSC) acidic pressure leaching has been utilized to treat a number of ores, concentrates and recycled materials. This versatile technology offers many advantages including low temperatures, low pressures, low capital costs, low operating costs, faster throughput and less costly materials of construction than conventional pressure oxidation. This paper will elucidate the application of this technology for production of gold, silver, palladium, rhodium, zinc, germanium, gallium, cobalt, copper and nickel. Recycled material applications will also be elucidated. In addition, details of an application for treatment of a refractory chalcopyrite copper and gold bearing ore will be presented and pertinent economics discussed.

Jan 1, 2004

By H. J. McQueen

Aluminum was hot worked at 400 - 500°C and strain rates (e ) of 0.004 -0.1s-1, under reversing strains (c) of 0.5 to 0.2 or 0.5 to 0 and also advancing from 0.5 to 1 or 0.5 to 5. Under similar test conditions for different parts of the strain paths, the average measured flow stresses are found to agree with each other. In the forward and backward strain path tests, the almost identical steady state plateaus affirm the occurrence of dynamic recovery (DRV). On reversal of strain direction at constant e , there was generally negligible Bauschinger effect. In specimens annealed at 400°C, static recrystallisation (SRX) was followed microstructurally. mainly by disappearance of elongated grains with serrated boundaries because the new grains were only little a finer than the old due to low strain energy. The only influence of reversing strain path observed was the effect of change of grain boundary area as grains elongated or returned towards equiaxed. In optical microscopy, elongated grains with serrations and deformation bands confirmed DRV in forward path specimens. In reverse path specimens, equiaxed grains were gradually restored with retention of serrations and bands. In low magnification polarized optical microscopy, grain alignment increased with strain for forward path specimens; whereas it decreased in reverse path ones, supporting DRV. Orientation imaging microscopy (OIM/SEM) revealed that elongated grains are broken up as deformation bands rotate during the forward path and that grains return to equiaxed appearance on backward straining. Comparative studies using optical microscopy in polarized light (POM), OIM/SEM and transmission electron microscopy (TEM) revealed that while subgrains remain equiaxed and constant in size and character during the forward and backward paths, the fraction of low angle facets decreased while that of high angle grain facets increased with increasing strain; these are coupled with a fairly low fraction of medium angle boundaries. The results contribute to the understanding that dynamic recovery in aluminum maintains sub-boundaries with low misorientation but as grains elongate and more subgrain become adjacent to grain boundaries the fraction of high angle boundaries rises (with backward straining it was vice versa).

Jan 1, 2007

By K. Hanumantha Rao, A. Javadi

Our recent studies revealed that the sulfide minerals in contact with water during grinding produced hydrogen peroxide (H2O2) where the amount of H2O2 production by the minerals found to be in the order of pyrite > chalcopyrite > sphalerite > galena. The H2O2 effect on the oxidation of pulp components and its influence on the concentrate grade and recovery in flotation have been studied and the results have been presented and discussed in this paper. Studies have also been carried out to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp and as well of controlling the formation of these species through known chemical means for depressing the generation of the oxidant. Flotation tests using a complex sulfide ore with the same reagent scheme that is being used at Boliden concentrator in Sweden but with the addition of i) collector and depressant, ii) Na2S reductant and iii) inorganic (EDTA) and organic (TETA) surface modifiers, during grinding stage have been performed to judge the beneficial or detrimental role of H2O2 on the selective flotation of sulfides. The results demonstrate that the selectivity of metal sulfides against pyrite increases with increasing generation of H2O2 in the pulp liquid. H2O2 is also found to be a better oxidant in chalcopyrite-galena flotation separation than the commonly used K2Cr2O7.

Jan 1, 2016

By E. Lee Cameron

The old mine workings on four barite-fluorite veins of the Lake Ainslie district, Nova Scotia, were opened recently and channel sampled. The samples were then forwarded to the Ore Dressing Laboratories, Bureau of Mines, Ottawa, for chemical analyses. Following the analyses, the sample rejects were combined to form bulk samples, representing ore from each vein, for small-scale batch test work. Tonnage samples from the veins, for pilot mill testing, were submitted when requested by the Bureau. The results of the analyses on the channel samples showed that there are two grades of ore in the di strict, represented, for test purposes, by the Trout River vein and Johnson vein ores. Small-scale and pilot-plant test work was undertaken on both these ores. The Trout River ore is amenable co concentration but, because of the high-barite-co-fluorite-co-calcite ratio, a fluorite concentrate was not obtainable from the Johnson vein ore as received. However, Johnson ore blended in a 1 :1 ratio with Trout River ore gave a mill feed that was readily concentrated. The test work on these ores showed that the following concentrates are obtainable : (a) A barite concentrate, with a recovery of 85 to 95 per cent of the available barite, analysing 93 co 96 per cent BaS04, 4 co 6 per cent CaF,, and 0.5 co 2 per cent CaCO3. (b) A fluorite concentrate, with a recovery of 80 co 85 per cent of the available fluorite, analysing 94 to 97 per cent CaF, , 1 to 3 per cent BaSO., and 1 to 3 per cent CaCO3

Jan 1, 1945

By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By M. Barati

A collaborative research between University of Toronto and Hatch was conducted to understand and optimize the process conditions pertaining to a novel steelmaking technology. In this technology, known as CRISP, direct reduced iron is continuously melted and refined in a stationary electric arc furnace. The major challenge against continuous operation of the electric furnace was identified to be minimizing the corrosion of the refractory in order to achieve uninterrupted operation for a minimum of one year. Theoretical analysis and bench scale experiments together with two pilot runs resulted in defining an operating window for slag chemistry that would minimize chemical attack to the refractory while satisfying the oxidizing conditions required for sufficient decarburization. An analysis of the process in terms of energy consumption and emission of greenhouse gases revealed that it is superior to the current batch DRI-based steelmaking technologies.

Jan 1, 2011

By Steven D. Botts

The Antamina project, owned by BHP Billiton Plc, Mitsubishi Corporation, Noranda Inc., and Teck Cominco Ltd. , is a $2.3 billion copper/zinc project, located in the Ancash Department in Perú. The project consists of an open pit mine, a 70,000 ton per day concentrator, a 302 Km. long concentrate pipeline, port facilities, a new access road, power line, and town site. The project is designed to produce up to 1.5 million tonnes per year of copper and zinc concentrates over a 23-year project life, and will be the third largest producer of zinc and the seventh largest producer of copper in the world. This mega project is the largest mining investment in the country and, during its construction stage, was the most important construction project worldwide. On May 28th, 2001, Antamina commenced testing operations and four months later, it reached commercial production. Antamina was officially inaugurated on November 14th, 2001 by Peruvian president Alejandro Toledo. The construction stage of the project generated 8,000 direct jobs, with a peak of 10,000 employees, and 30,000 indirect jobs. The permanent workforce consists of approximately 1650 employees, the vast majority of which are Peruvian Nationals; around 30% of whom came from the department of Ancash where the deposit is located. Approximately 5,800 indirect jobs will be generated from the project. Independent sources state that Antamina will increase the Peruvian mining exports by 30% and Peruvian GDP by 1.4% within its first year of full operation in 2002. Since winning the privatization bid for the project in 1996, the company has implemented a successful approach to community development and environmental protection based on sustainable development principals. Throughout the development of the project, a number of initiatives have been undertaken to ensure full involvement of the local populations in community development activities and the company?s environmental program. Due to its size, difficult logistics, cultural considerations and financial aspects, the project has faced a number of unique challenges in the area of environmental protection and management of community interaction. Antamina has been innovative in its approach to these issues, and as a result, has set new standards in Perú for environmental and community management, and sustainable development.

May 1, 2002

By H. Hamza

Efficient and effective management of extraction process tailings is an essential ingredient for the continued success and development of Alberta's vast oil sands resources. Open-pit oil sands operations north of Fort McMurray recover bitumen from flotation circuits. Process tailings are managed in carefully engineered and monitored external tailings management facilities and in below-grade mine pits. In order to support reduction of production costs and improve upon established tailings management practices, CANMET has been working with the oil sands industry in a collaborative framework to assess the potential to integrate thickened tailings into oil sands extraction process flowsheets. Albian Sands has commercialized the process while others, including Syncrude Canada Ltd., continue to evaluate the suitability of the process for their operations. This paper provides an update on R&D work undertaken in recent years to assess and develop the potential of thickened tailings technology for the open-pit oil sands operators of northern Alberta. The aim of this work was to explore opportunities to optimize process efficiency and environmental sustainability by improving water and energy conservation and develop more alternatives for tailings management and reclamation.

Jan 1, 2004

By Dani J. Alldrick, Alastair J. Sinclair, Colin I. Godwin

"Abstract - The Stewart mining camp has a long history of precious and base metal mining. The camp is abundantly mineralized, with more than 200 widespread, varied, vein prospects, deposits and orebodies. These show wide variations in the mineralogy of ore, gangue and alteration assemblages, and wide variations in textures and structural settings. This report establishes the timing of the different metallogenic epochs and suggests a specific exploration application for systematic lead isotope analyses.Galena lead isotope ratios from a range of mineral occurrences indicate that all these varieddeposits formed during two main mineralizing events. Lead isotope data from the Stewart mining camp do not provide absolute ages for the formation of mineral deposits, but the relative distributions of data are consistent with dates determined in other studies. One ore-forming episode occurred in the Barly Jurassic and the other in the Middle Eocene. Both metallogenic epochs were brief, regional-scale phenomena. Sorne deposits from the younger mineralizing episode were em­ placed adjacent to or superimposed on the older deposits.Field and laboratory studies show that the two metallogenic epochs are characterized by different base and precious metal suites: Barly Jurassic gold-silver-zinc-lead-copper; and Middle Eocene silver-lead-zinc. Therefore, showings of different ages have different base and precious metal potentials and deserve different exploration emphasis. Lead isotope studies provide a reliable, cost-effective method for evaluating the age and commodity potential of small or recently discovered mineral showings and for setting exploration priorities on properties with several varied mineral occurrences . The determination of the age and metal potential of a prospect at an early stage of exploration may govern the urgency, intensity or even the necessity for further exploration work."

Jan 1, 1993

By N. L. Richards

In manufacturing for the 21st century, the first company to market often leads the pack in product development and sales. In this respect, manufacturing processes play an important role in transforming “raw materials” into a product(s) for sale to a customer. Thus it can be seen that upfront modelling of a design concept, or modelling of manufacturing processes in a plant, can play an important role in effectively ensuring the overall design and manufacturing route is carried out in an expeditious manner. In the paper various scenarios are considered with respect to modelling the microstructure and/or process, in various manufacturing processes. Also considered are the effects of service condition on the manufactured product in terms of creep and fatigue.

Jan 1, 2010

By D. G. Eskin

"It is well known that it takes some time for the solid phase to completely dissolve upon melting, especially inside the defects of insoluble particles, e.g. oxides. Until then the oxides remain active solidification substrates in the case of subsequent solidification. It is also known that ultrasonic melt treatment causes grain refinement through activation and dispersion of solidification substrates (one of the mechanisms) and also accelerates the dissolution of solid metal in the melt. In this study we combine these effects and demonstrate that the introduction of an alloy rod into the matrix melt of the same composition results in significant grain refinement, this effect being increased by the ultrasonic vibration of the rod. The achieved grain size is comparable to that obtained by a standard Al–Ti–B grain refiner. All samples were cast using a standard TP-1 mould to enable correct comparison. The effect of the temperature range of the rod introduction, as well as the effect of ultrasonic vibrations are discussed.INTRODUCTION The fact that by introducing solid metal into the melt one can achieve structure refinement is rather well known. As early as in the 1930s–1950s a series of papers and patents have been published, showing the benefits for grain refinement when dissolving solid metal in the melt before solidification (Danilov and Neimark, 1938; Scheil, 1956). Later on this way of structure refinement was developed further and dubbed “suspension casting” or introduction of “internal chills” (Madyanov, 1969; Zatulovsky, 1981). The solid metal was added in a form of cut wire, cut sheet, or powder, with the resulting grain refining, elimination of columnar grain structure in ingots and castings of steel, copper and aluminium alloys. The underlying mechanisms have been suggested as (1) rapid cooling of the melt due to the latent heat consumption upon melting of the solid metal with the resultant melt undercooling and (2) introduction of many solidification substrates in the form of crystal fragments and active non-metallic inclusions (Danilov & Neimark, 1938; Balandin, 1973). A number of patents have been filed where either the same solid alloy or a master alloy with additions (e.g. Ti for Al alloy) is introduced in the amounts up to 50% (typically less than 10%) into the melt close to the liquidus temperature (Schmidt, 1966; Talbot & Soller, 1973, Krupp, 1974; Bondarev, 1979). The main reason that this technique is not widely used in industry is the possible incomplete dissolution of the solid parts introduced into the melt with ensuing inhomogeneous as-cast structure and potential defects. Also the selection of the temperature range where the technology works the best is not clear."

Jan 1, 2018

By Carl Pelletier

The Sigma-Lamaque Complex is considered a lode-gold deposit characterized by narrow vein structures, which have been mined historically by underground methods. In addition to the narrow vertical structures, mining also took place on horizontal veins, ?North Dipper? veins and dykes mineralized with sub-horizontal veins and stringers. Over the 60 + years of production, mining took place to a depth of 1.8 km. The upper portion of the deposit was considered all but exhausted, when viewed from an underground mining perspective. The year 1998 is considered a turning point for the Complex when a small open pit was mined at Sigma. The resource evaluation methods used underground were applied to surface mining, which allowed small pits to be mined. The resource evaluation method considered only the narrow vertical structures and was not well adapted to open pit mining. As a consequence, resources were consistently under evaluated. It became clear that a new geological approach was necessary to more accurately define resources (i.e., what was being mined). In order to integrate all characteristics (geometry, mechanics and chronology) of this complex lode-gold deposit, a new geological model was proposed. Due to this new approach, dating to February 2000 and updated in December 2000, the reserves evaluated in the first 180 meters now stand at 15 million tonnes @ 2.61 g/t Au (1,265,350 oz). Those reserves cover an east-west corridor extending 1,500 m by 750 m.

May 1, 2001

By S. C. Ellis

THE bituminous sand of northern Alberta has already an extensive literature, and most of the reports dealing with the subject are still available (see Selected Bibliography at end of paper). A phenomenon so striking and, as regards its extent, so unique, as the deposit in the vicinity of McMurray settlement could not fail to attract the notice of the early explorers, and we find references to it as far back as the latter part of the eighteenth century. However, scarcely a thought had been bestowed upon the possible economic value of minerals in the the remote northern parts of Canada before the second decade of the present century, and practically no detailed mapping had been done north of the town of Athabaska. The late Wm. Ogilvie made a track survey of Athabaska river in 1884, and surveys of certain lines-including the 23rd base line-had been completed by 1911. Between this base line and lake Athabaska, nothing had been attempted. Actually, no definite information at all was available regarding the character and extent of the bituminous sand when, in the earl y summer of 1913, a reconnaissance party set out from Athabaska for McMurray. At that period, the journey was made in summer by scow or canoe. No telegraph line had been laid, and a casual mail service by canoe or dog team once in three months formed the only means of communication with the outside world. The investigation has begun by the Mines Branch was continued during several subsequent years. The sand deposits were studied and sampled, the bi rumen was extracted from the sand and studied chemically and physically, and the economic significance of the deposit was given exhaustive study.

Jan 1, 1937

By P. Leo

Al-Mg-Si alloys are widely used as medium-strength structural materials; extrusion is the most common processing route. In the present hot deformation investigation of a 6060 alloy, the microstructure of the alloy has been analyzed in the as-cast state, after homogenization heat treatment and after hot deformation by tensile tests in the range 400-490°C and 10-4 to 10-2s-1 on both as cast and homogenized alloys. After deformation the microstructure of the as-cast alloy exhibited cavitation. The flow curves at the lowest test temperature T show a gradual softening after a stress peak, being more evident for the alloy deformed in the homogenized state in association with a high yield stress; at higher T a plateau is attained which is lower as T rises and strain rates decrease. For each fixed T, the ductility decreases as strain rate increases for the homogenized alloy whereas, for the as cast alloy, it rises with strain rate. Constitutive analysis gives Q = 240kJ1mol for the homogenized alloy in agreement with published values; this indicates a more rapid strength decline with rising T than Al, suitable for good hot workability along with the lack of cavitation.

Jan 1, 2011

The Discrete Element Method (DEM) is a powerful tool for analysing the flow of charge, the energy consumption and the pattern of energy utilisation of a SAG mill. With the development of laser scanning measurement, the detailed internal working surfaces of a SAG mill can now be included in DEM models. Using scanned results for new and worn shell liners for a 32? (9.75 m) SAG mill, it is shown that the feed and discharge lifters have significant effect on the flow of the charge introducing significant threedimensionality. The effects of the resolution accuracy of liner geometry and the lower cut-off of the rock size distribution are explored. Finally, using a matched new and end of life worn liner and operating conditions taken from site surveys, the effect of wear on charge motion, distribution and energy utilisation are evaluated.

Jan 1, 2012

By Ian E. Efford

The paper gives an assessment of Canada's energy supply-and-demand position, the current situation and projections into the future, as well as a review of some alternative energy futures for Canada. The main elements of Canada's energy strategy for the period 1977-1990, with particular reference to the role of energy conservation, are discussed, leading in to the development of the national energy conservation program.

Jan 1, 1977

By A. M. Cann, C. I. Godwin

"The Kemess porphyry copper-molybdenum deposit occurs in the Intermontane Belt of north-central British Columbia. The deposit is in andesitic to basaltic flows and tuffs which may be correlated with the Savage Mountain Formation of the Upper Triassic Takla Group. Most known chalcopyrite and molybdenite is associated closely with a 500-m-diameter zone of intense quartz-sericite-pyrite alteration. A zone of supergene enrichment, up to 30 m thick, underlies a leached capping about 20 m thick. The age of mineralization and the surrounding granodiorite and quartz monzonite pluton is Early Jurassic. K-Ar and Rb-Sr analyses indicate that the mineralization and alteration is slightly younger (l82±6 Ma) than the granitic intrusion (KAr: about 205±6 Ma; Rb-Sr: 190±4 Ma). The low 87Sr/J6Sr initial ratio for the granodiorite is typical of plutons in the Intermontane Belt.IntroductionKemess is a medium to small porphyry copper-molybdenum deposit with significant gold and silver values (Pilcher and McDougall, 1976). This paper describes the lithologies and alteration at this property; geochronology by Rb-Sr and K-Ar methods defines the ages of mineralization and surrounding plutons to be Early Jurassic.The property, located in the Thutade Lake area of northcentral British Columbia (NTS Map 94E; lat. 57°04'N; long. 126°44'W), is about 425 km northwest of Prince George (Fig. 1). Closest road access is 35 km southeast of Kemess. Final access must be by float plane or helicopter. The British Columbia Railway right of way passes 70 km to the southwest of theproperty.A prominent gossan zone at Kemess was staked in 1967 by Kennco Explorations (Western) Ltd. following detection of geochemical anomalies during stream sampling the previous year. During 1968, 1969and 1971, Kennco completed 232 m of X-ray diamond drilling, conducted geological mapping and carried out geochemical sampling of silts and soils (Stevenson, 1969; B.C. Ministry of Energy, Mines and Petroleum Resources, G.E .M., 1969 and 1971). Getty Mines Ltd. optioned Kemess in 1975and 1976. They remapped the area and diamond drilled 12 BQ and NQ holes, totalling 2065 m (B.C. Ministry of Energy, Mines and Petroleum Resources, Expl. B.C., 1975)."

Jan 1, 1980

By J. A. Morgan, P. M. Dimmell

Abstract - The Aubry pegmatites are located on the Seymour Lake property, 15 km north of Lake Nipigon in northwestern Ontario. The property lies within the Caribou Lake-Marshall Lake greenstone belt along the English River-Wabigoon subprovince boundary of the Superior province of the Canadian Shield. The property was optioned in March 2001 by Linear Resources (now Linear Gold Corp.), who carried out gridding, prospecting, geological mapping, soil and lithogeochemical sampling, trenching, channel sampling, and a total of 1,866 m of diamond drilling in 32 holes. The Aubry pegmatites are classified by Breaks et al. (2003) as complex type, spodumene-subtype, lithium-cesium-tantalum pegmatites (Cerný, 1989). These pegmatites generally form under high-pressure-low-temperature conditions, display complex internal zoning, have relatively low Nb/Ta ratios in the ore-forming assemblages, and contain significantly elevated tantalum values (Cerný, 1989). Other examples of spodumene-subtype pegmatites include the formerly producing Hugo pegmatite in South Dakota, and the currently producing Greenbushes pegmatite in Australia. The Aubry pegmatites occur as an undulating system of stacked sheets that dip moderately to steeply eastward over a 1-km strike length. The main portion of the North Aubry pegmatite ranges in true thickness from 10 to 28 m over a strike length of 125 m, whereas the thickest portion of the South Aubry has an estimated true thickness of 15 to 16 m over a minimum strike length of 95 m. The North Aubry pegmatite remains open downdip and along strike to the north, whereas the South Aubry pegmatite remains open downdip and along strike in both directions. The Aubry pegmatites are among the most highly evolved in Ontario, with the southern end of the North Aubry (trench 5/6 area) being the most highly fractionated (Breaks et al., 2002). Channel samples from the trench NA-5 area of the North Aubry pegmatite produced values up to 2.49 wt.% Ta2O5 over 4 m. Coarse manganotantalite crystals, up to 5 cm in diameter, from this trench contain up to 84.9 wt.% Ta2O5 (Breaks et al., 2002). Drill hole SL02-31 in the trench NA-6 area gave values of 0.046 wt.% Ta2O5 over 17.7 m, including 1 m @ 0.464 wt.% Ta2O5. Further exploration will focus on defining the grade of the North Aubry zone, extending and defining both known pegmatites, and identifying additional Ta-rich zones within them. Lithogeochemical and enzyme leach soil geochemical data suggest the presence of multiple undiscovered pegmatites on the property.

Jan 1, 2005

By D. J. MacKinnon, Kazi E. Haque

Ammonia present in a variety of mine/mill waste waters was almost completely oxidized to nitrogen by chloride mediated electro-oxidation. A closed circuit operation of preconcentration of ammonia on a suitable adsorbent (e.g. zeolite or a resin) followed by brine stripping of ammonia and electrolysis of the strip liquor seems to have sound technical, economic and environmental merits. The removal of ammonia, cyanide, cyanate or thiocyanate from a mine/mill waste water (e.g. gold mill), either individually or collectively, is also feasible by chloride mediated electro-oxidation technique. Further R&D investigations are necessary for the development of a closed circuit operation for the removal of ammonia, cyanide and thiocyanate; and also to obtain technical data for process cost estimates

Jan 1, 1996

By M. J. Merwin

Heat treated seamless tubular products are processed in a fashion that can be easily modified to produce dual phase microstructures, through the implementation of intercritical soaking prior to quenching. Dual phase steels are known to possess low yield strength compared to tensile strength. The steel line pipe market is interested in low yield-tensile ratio materials for application in reel barge pipe laying operations. In the current work compositions of commercially produced material already in use for the line pipe market were examined and dual phase microstructures were successfully developed. The microstructure and properties of the materials were found to be stable over the range of intercritical temperatures employed. Tempering temperature and, somewhat unexpectedly, small chemistry differences were found to have the largest influence on properties. Excellent toughness performance was observed in samples tempered at temperatures in excess of 550°C. Tempering in this temperature regime produced materials with strength suitable for application as API X60 line pipe. A difference in tensile strength between steels of similar chemistry was observed, and is not fully understood at this time. Welding performance was considered through simulation of three regions of the heat-affected zone. Neither intercritical temperature, nor tempering temperature, were found to have a significant influence on the heat-affected zone properties. The peak temperature achieved in the thermal cycle was the only significant factor. The hardness of the heat-affected zone was found to increase continuously with increasing peak temperature. While toughness was found to be low for both partially-transformed and coarse-grain heat-affected zones, the toughness of the fine-grained heat-affected zone was substantially better. Based on the results found in this laboratory study, a limited production trial is expected.

Jan 1, 2005