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By Soumitry J. Ray

Poor visibility of powered industrial vehicles, such as forklifts, used in industry is often the cause of accidents that include pedestrians. Current standards allow up to 20 % non-visible regions for forklifts where measurement of these regions is performed by using lamps. A collaboration of research organizations, including National Institute of Standards and Technology, Georgia Institute of Technology (NIST), and Direct Dimensions, has been evaluating advanced methods for measuring a forklift operator?s visibility. These methods can potentially improve visibility standards. They can also help forklift and sensor manufacturers to determine (1) how visibility-assist sensors and algorithms can be designed and (2) where sensors can be mounted on forklifts. This paper includes explanation of visibility measurement experiments performed and results, associated language suggested to standards organizations, and a prototype design for measuring the visibility of forklifts automatically.

Aug 1, 2013

By K. J. Fair, G. Van Weert, J. E. Schneider

"IntroductionCyanidation is the principal process for extracting gold from ores . Many primary gold ores, however, are partially or totally refractory in the conventional cyanidation process.Considerable success has been achieved with new gold leaching techniques, such as intensive cyanidation, pressure cyanidation, carbon-in-leach cyanidation, etc. These techniques however, do not offer substantial gains in gold extraction from refractory pyrites.The more drastic pretreatment processes such as roasting, chemical oxidation, autoclave oxidation, and bacterial oxidation all utilize oxidation to break down the structures of pyrite and arsenopyrite. This generally renders the gold amenable to cyanidation.Comparative cost studies indicate that the oldest commercial pretreatment method, i.e. high temperature roasting, is currently the least expensive option if the sulphuric acid can be sold. It operates with air at atmospheric pressure and is characterized by fast reaction rates. For an alternative hydrometallurgical con centrate treatment method to be competitive, it too should operate with air at atmospheric pressure and with fast reaction rates. The NITROX process meets these conditions."

Jan 1, 1986

By R. D. Brown

The Federal Government's White Paper on Tax Reform received further major criticism in the reports of the Committees of the House of Commons and the Senate, which recently completed a lengthy review including public hearings of the government's proposals. These reports both criticized the emphasis placed by the White Paper on its concept of tax equity rather than on a system which would promote economic growth. However, the Finance Committee of the House of Commons was prepared to accept, with modifications, a number of the White Paper's key reform proposals. The Senate Finance Committee was more critical of the basic thrust of the tax reform program and recommended that a modification of the existing tax system would be more appropriate to Canada's needs. Both Committees re-commended a more favourable treatment of mining income than that originally proposed in the White Paper, and to some extent both Committees suggested proposals that were even more favourable to the industry than those set out in Finance Minister Benson's amended proposals made in August of this year. This article out-lines the principal recommendations and comments in the reports of both the House of Commons Committee and the Senate Finance Committee.

Jan 1, 1971

By Thom Mambe, Angelo Fernando

The objective of this work was to identify key parameters related to the reduction of the sulphur content in ammonium diuranate (ADU), and the identification of solid products being formed under various operating conditions. A laboratory-scale, continuous ADU precipitation circuit was assembled using a glass reactor vessel immersed in a temperature-controlled water bath. A pre-prepared uranium feed solution was fed continuously using a peristaltic pump. Anhydrous ammonia mixed with compressed air was metered and pumped using a double-headed peristaltic pump. An over-head mixer was used to keep the solids in suspension. The precipitated ADU slurry was removed from the reactor at the same flow rate as the feed solution. The slurry was sampled to generate ADU solids for chemical and physical analysis after four hours of continuous operation to ensure steady-state conditions. The following variables were studied to determine their influence on the sulphur content in the resulting ADU. (a) sulphate:uranium molar ratio in the reactor (1:1, 1:5, 1:10 and 1:20) (b) precipitation pH ( pH 6, 6.5, 6.9, 7.5 and 9) and (c) precipitation temperature (40C and 60C) A total of 18 tests covering the above parameters were conducted, and the results indicated that the sulphur content in the resulting solids was highly dependent on the reaction pH. Out of the pH levels tested, tests completed at pH 6.9 and 7.5 generated solids containing the lowest sulphur contents, between 0.5 to 1.5% S uranium basis (UB). The sulphur content in solids was found to vary linearly with the sulphate:uranium ratio in the feed solution, showing a statistically valid correlation. The impact of temperature was minor between 40°C and 60°C, with a slight advantage at higher temperatures. Tests at a sulphate:uranium ratio of 1:1 produced solids with the lowest sulphur contents. The influence of pH or temperature on sulphur content in solids was almost non-existent at this sulphate:uranium ratio. Precipitation pH is the major factor influencing ADU sulphur content, followed by the uranium to sulphate ratio.

Jan 1, 2020

By R. A. Hemstock

"Simple classification systems are now being used which will describe adequately the surface vegetation, the topography and the peat for any muskeg condition. Good progress is being made in determining some of the mechanical properties of muskeg and it is apparent that the science of soil mechanics will apply largely to these studies. Correlation is also indicated between shear strength as determined by the shear vane tester and vehicle performance. Several tracked vehicles are now available which perform well in muskeg and advances in this field have come rapidly in the past few years. Testing is under way on the largest of all muskeg vehicles -the thirty-five ton Musk Ox. This vehicle will fill the last gap for the oil industry and will make possible the movement of large drilling rigs at any season of the year."

Jan 1, 1960

By Yvon T. Maurice

Under the auspices of the Federal-Provincial Uranium Reconnaissance Program, a geochemical orientation survey was undertaken in an area of uraniferous Lower Proterozoic (Aphebian) rocks near Cape Dorset in southwest Baffin Island. The main objective of this study was to establish a methodology for a future reconnaissance geochemical program using lake samples over a 300-mile Lower Proterozoic rock belt that occurs along the southern coast of Baffin Island. Mineralogical and chemical studies of known radioactive occurrences, combined with detailed sampling of secondary environment media in the vicinity of the showings. indicate that uranium is the most significant pathfinder, despite considerable enrichment of other metals in the uraniferous rocks, Significant geochemical patterns produced by uranium in lake waters and uranium in lake sediments have been obtained, but their relative usefulness depends on the distribution of carbonate bedrock, which in turn affect the bicarbonate content of lake waters. In southern Baffin Island, because of erratic variation in lake-water alkalinity, it is recommended that both water s and sediments be sampled on a routine basis. The need for lake-water acidification to prevent depletion of soluble metal ions in samples resulting from adsorption on the walls of the containers and/or suspended solid matter is discussed briefly. The base metal potential of the area was examined in some detail and found to be significant, particularly for a Lower Proterozoic gossanous formation that occurs throughout southern Baffin Island.

Jan 1, 1977

By Y. Tang

"Rare earth elements (REEs) have many key applications in traditional and advanced technologies. A shortage of several critical REEs is expected due to the discrepancy between the availability of REEs from REE deposits and the REE demand from the market. REE recovery and separation from secondary resources such as uranium wastes and recycled materials might help balance the shortfall in a cost-effective way. This paper presents data concerning the recovery of heavy REEs (HREEs) from uranium raffinate. It also discusses the design, commissioning, and operation of a solvent extraction pilot plant for the separation of REEs.RÉSUMÉ Les éléments des terres rares (ÉTR) trouvent de nombreuses applications importantes dans les technologies classiques et de pointe. On prévoit une pénurie de plusieurs ÉTR critiques en raison des divergences constatées entre la disponibilité des ÉTR provenant de gisement d’éléments des terres rares, et la demande d’ÉTR sur le marché. La récupération et la séparation des ÉTR à partir de ressources secondaires telles que les déchets générés par le traitement du minerai d’uranium et les matériaux recyclés pourraient contribuer à équilibrer cette pénurie de manière rentable. Cet article présente des données relatives à la récupération des ÉTR lourds (HREE, de l’anglais heavy REEs) à partir de raffinat d’uranium. Il aborde également la question de la conception, de la mise en service et de l’exploitation d’une usine pilote d’extraction par solvants pour la séparation des ÉTR INTRODUCTIONSignificant amounts of strategic specialty heavy rare earth elements (HREEs) are present in waste streams in Saskatchewan uranium operations. Selective precipitation including neutralization, oxalate, and double-salt precipitation, as well as sulfide precipitation, ion exchange (IX), and solvent extraction (SX) are commonly used technologies for the recovery and purification of rare earth element (REE) solutions. REE oxalate precipitation can effectively remove Fe, Al, Ca, Si, and other impurities by taking advantage of the solubility difference between REE oxalates and impurities in the acidic solution (Xu, 2005)."

Jan 1, 2018

By J. S. Edwards

The ISASMELT? process is recognized worldwide as a modem, flexible, environmentally-friendly and low capital cost smelting technology. Due to the inherent simplicity, and the advanced process control that has been developed, personnel become competent within weeks of being introduced to the ISASMELT? technology. This compares with the years required to become proficient with alternative technologies. Copper smelters in Australia, USA, India, China, Peru and Zambia have installed ISASMELT? technology under licence from Xstrata Technology. In the secondary copper business, plants in Belgium and Germany are processing copper and/or lead materials in ISASMELT? furnaces in a two stage process. In a single furnace smelting is followed by converting. Both plants have exceeded design capacities and are continuously improving their performance. The next evolutionary step for the technology is the implementation of the continuous copper converting process on a commercial scale. The present work describes the design status of the continuous converting process - ISACONVERT?.

Jan 1, 2007

By W. G. Hubler

It has been within only the last two or three years that enough progress has been made in preferential flotation to warrant metallurgists in recommending the installation of commercial-sized plants for the treatment of copper-zinc-iron ores. Until the new processes had been worked out successfully, the treatment of this type of ore had proved a stumbling block in the path of metallurgical progress. Separation of lead-zinc ore is comparatively simple. A lead-zinc ore low in iron may be separated and concentrated by gravity con-centration, provided it is not necessary to grind too fine. Owing to the specific gravity of chalcopyrite and sphalerite being so nearly the same, however, their separation by gravity concentration is out of the question. Complex lead-zinc-iron ores in which the several minerals are intimately associated, requiring fine grinding to free them, have been successfully treated by flotation for the past fifteen years. Galena is easily floated, and its flotation, unlike that of chal¬copyrite, is not affected by the reagents used to inhibit the flotation of sphalerite and iron sulphides. When an attempt was made to use the methods of lead-zinc se-paration on copper-zinc ores, it was found that the depressant re-agents added to inhibit the flotation of the iron and zinc minerals would, under certain conditions, depress a large part of the copper. It was also recognized that, in the grinding of copper-zinc ore, soluble salts were generated which were detrimental to flotation unless properly controlled. The main part of this paper will be a discussion of solutions in the grinding circuit in relation to the pro¬duction of soluble salts and their effect on flotation.

Jan 1, 1931

By John J. Laffin

"Nova Scotia Department of Mines and Energy Throughout the history of Nova Scotia, trends in the production and use of its coal resources have resulted in major impacts on the economy and society of the province. Current trends in coal demand locally, nationally and internationally are having and will have an increasing positive effect on Nova Scotia over the next twenty years-in terms of energy supply, job creation and general economic development. Coal for electrical generation is an immediate and key objective of Nova Scotia's energy plan; and, in the long term, coal-derived fuels will meet the province's needs for transportation fuels. Demand for metallurgical coal is also expected to increase, especially if the merchant coke plant currently under investigation becomes a reality.Meeting these coal supply and utilization objectives in the face of increasing environmental, social and economic constraints poses a tremendous technical challenge. Work has begun on projects to expand coal production capacity and to adapt new technologies for coal preparation and utilization to the specific needs of Nova Scotia; much more work will be required in the coming decade in order to succesfully tap this resource.IntroductionThe energy problem facing Atlantic Canada has a few unique features not found in the rest of the country. Canada, as a whole, has access to a diverse mix of energy resources, including crude oil, natural gas, coal, hydro and uranium, with the result that crude oil supplies only about 40 per cent of Canada's primary demand. In contrast, foreign crude oil dominates Atlantic Canada's energy mix, supplying over 70 per cent of the primary energy demand.This results in important differences in various sectors. Nationally, about 5 per cent of the electricity is generated from oil whereas last year in Nova Scotia approximately 40 per cent of the electricity generated was from imported oil. Residential, commercial and industrial space heating, and industrial process heating in Atlantic Canada was almost 100 percent dependent on foreign oil. This is in sharp contrast to the situation in central and western Canada, which have access to secure domestic natural gas, oil and hydro electricity."

Jan 1, 1982

By C. T. Harper, B. J. Fryer, R. P. Taylor

"IntroductionThe Maurice Bay deposit is one of a number of uranium deposits that have been found in recent years in the Athabasca Basin of northern Saskatchewan (Tremblay, 1982). This deposit, along with the others, belongs to the unconformity type deposits (Beck, 1977). They are, for the most part, polymetallic, being characterized by a suite of metals which include U, Ni, Co, Cu, Pb, Zn, Mn, V, Ag, Au, Pt-group elements, S, As, Bi, Se, Te, and Mo, some of which, besides U, are present in economic concentrations (Amok, 1974; Ruzicka, 1975; Tapaninen, 1976; Hoeve and Sibbald, 1978; Dahlkamp, 1978). The Maurice Bay deposit was known to be a small low grade deposit in which the ore was essentially monomineralic, consisting mainly of pitchblende (Harper, 1978). However, the occurrence of trace amounts of some of the elements common in the larger polymetallic ore bodies (e.g. Key Lake, Cluff Lake D) was anticipated. Thus a lithogeochemical sampling project was undertaken in 1979 across part of the Maurice Bay deposit (Harper, 1979). Major oxides (SiO2, Al2O3, FeO, Fe2O, MgO, CaO, K2O, Na2O, MnO, P2O5, and TiO2) and a group of the most common trace metals (U, Ni, Co, Cu, Pb, As, Au, V, and Se) were analyzed to determine whether any elemental patterns (halos or depletions) could be detected which would reduce the number of pathfinder elements needed for exploration purposes. In addition to the above metals, Th was also checked because some conglomerate strata in the Maurice Bay area are known to be thorium-enriched (Harper, 1978). Only the trace metal distributions will be discussed in detail in this report.General GeologyThe Maurice Bay area is underlain by three major groups of rocks, the White Lake metamorphic complex, an unnamed granodiorite complex, and the Athabasca Group, described previously (Fig. 1; Harper, 1979). Table 1 summarizes the stratigraphic features as deduced by geological mapping and the examination of drill cores."

Jan 1, 1986

By Dennis E. Bell

"This paper describes exploration and development to 1982 in the southern half of the northeastern British Columbia (Peace River or Northeast Block) inner foothills metallurgical coal belt. Gates Formation, Fort St. John Group, is the primary target; Gething Formation, Bullhead Group, is secondary. This part of the belt remains wilderness when compared to its other parts. Practical formational and structural mapping is described. A local problem known as the Secus Mountain or Mount Belcourt conglomerates is discussed. The three major explorers have been Denison Mines, PetroCanada, and Crows Nest Resources, all with partners. Initial mine construction and rail spur construction are continuing. The new town of Tumbler Ridge is being built. Introduction This paper describes exploration and development to 1982 in the southern half of the northeast British Columbia metallurgical coal belt. The area (Fig. 1) trends 120 km northwest from the Alberta border to the Wolverine River and Bullmoose Creek. The belt averages 15 km in width, and is 20 km at its widest. Physiographically, the area is dominated by rugged inner foothills, with relief to 1,500 m. The trend of the structures is transected by a dozen rivers flowing southwest to northeast away from the Continental Divide. The Rockies, lying immediately to the west, control the climate. One fact continues to colour all coal work in the area. When compared to the other parts of the western Canadian foothills and Rockies coking belt, it remains the least accessible and least mapped portion. Lack of access also makes all work expensive. Current activity centres about two mines in construction at the northwestern end of the area. Denison Mines and partners are developing their Quintette project, and Teck Corporation and partners are developing their Bullmoose project. PetroCanada and partners have intensively explored their Monkman-Duke Mounta,in project, but mine construction awaits better economic times. The rest of the area remains lightly explored, with the exception of some intensive work on particular structures by Denison and Petro-Canada. The focus of coal work has been metallurgical bituminous coal seams contained primarily in the Gates Formation (Fig. 2) and secondarily in the Gething Formation. These formations are found in generally en-echelon structures ranging to several kilometres in width."

Jan 1, 1985

By S M. Roscoe

Relationships of Noranda sulphide deposits to volcanic rocks are reviewed and chemical variations within the volcanic sequence are described. The assemblages of minor elements in the pyrites and pyrrhotites of the Noranda and l\llatagami deposits are similar and are characterized by a high content of cobalt, tin and other elements. Isotopic compositions of lead, other geochronological data and stratigraphically disposed zonal distributions of sulphides and minor elements indicate that the deposits were formed prior to folding and metamorphism. Lead isotope data indicate that the Matagami deposits, and several others, were probably formed about 2.95 x 109 years ago and that the Noranda deposits may be about 50 million years younger. The volcanic sequence at Noranda is younger than the thick sequences bordering it on the east and on the west. The relationships are consistent with the hypothesis that these strata-bound sul1>hide de-posits are coeval with their associated volcanic rocks. T HE writer has been engaged in a metallogenic study of the region between Sault Ste. Marie and Chibougamau. An essential objective of this study is the classification of mineral deposits with regard to their composition, form, geological

Jan 1, 1965

By M. R. Coffin

Since the plant startup in 1972, the leaching and jarosite precipitation circuits at the zinc plant of the Kidd Metallurgical Division have been reconfigured several times to improve overall performance, and/or to respond to market conditions. For the most part, the circuit changes have been driven by two market factors: the price of zinc and the price of silver. Until recently, circuit modifications undertaken to improve zinc extraction and recovery came at the expense of silver recovery, and vice versa. In 2004, the plant was modified once again to produce a precious metals-bearing residue, but additional leaching circuits were added to ensure that zinc extraction and recovery did not suffer as a consequence. The development of the zinc plant of the Kidd Metallurgical Division is updated in this paper, with a focus on the recent circuit modifications and associated control strategies that were implemented to maximize zinc and precious metals recoveries, and control the quality of the jarosite residue.

Jan 1, 2006

By M. B. Kime

"A set of experimental batch leaching tests studied the effect of pH, time, temperature, and stirring speed on the relative Cu, Co, Ni, and Fe leaching yields of an oxidized copper-cobalt ore sample in an aqueous hydrochloric acid solution. The results were statistically analyzed and modelled using the structural equation modelling method. Models showed that Cu, Co, and Ni leaching yields were strong functions of the leaching time and leaching temperature, whereas the Fe leaching yield depended on the leaching temperature, stirring speed, and pH. Under optimum leaching conditions yields were 99.8% Cu, 82.4% Co, 91.3% Ni, and 30.6% Fe.RÉSUMÉ Une série d’essais expérimentaux de lixiviation en bâchée ont été menés pour étudier l’effet du pH, de la durée d’attaque, de la température et de la vitesse de brassage sur les rendements relatifs de lixiviation du cuivre (Cu), du cobalt (Co), du nickel (Ni) et du fer (Fe) d’un échantillon de minerai de cuivre-cobalt oxydé dans une solution aqueuse d’acide chlorhydrique. Les résultats ont été analysés et modélisés statistiquement à l’aide de la méthode de modélisation par équation structurelle (SEM, de l’anglais structural equation modelling). Les modèles ont montré que les rendements de lixiviation du Cu, du Co et du Ni dépendaient énormément de la durée d’attaque et de la température de la lixiviation ; le rendement de lixiviation du Fe, quant à lui, dépendait de la température de la lixiviation, de la vitesse de brassage et du pH. Dans des conditions optimales de lixiviation, les rendements étaient de 99,8 % pour le Cu, de 82,4 % pour le Co, de 91,3 % pour le Ni et de 30,6 % pour le Fe. INTRODUCTIONThe Katanga province in the Democratic Republic of Congo hosts the northwestern part of the Central African Copperbelt. This region abounds with large, rich deposits of sulfide and oxidized copper-cobalt ores. In general, the main valuable minerals present are malachite (CuCO3Cu(OH)2) and heterogenite (CoO(OH)). Common impurities found in heterogenite are Cu, Ni, Si, Al, Mn, and Fe. The substitution of Co by other cations (e.g., Cu, Ni, and Fe) has an influence on the crystallinity of heterogenite (Deliens, 1974). In general, well-crystallized varieties of heterogenite have lower impurity contents, whereas amorphous heterogenite types usually contain more impurities (Thys et al., 2009). Further, in heterogenite, Co can occur in the 2+ and 3+ oxidation states. The gangue generally consists of quartz (SiO2), talc (Mg3Si4O10(OH)2), kaolinite (SiO2·Al2O3·2H2O), limonite (Fe2O3·3H2O), and goethite (FeO(OH)). Oxidized copper-cobalt ores are often treated by hydrometallurgical methods, whereas sulfide ores are often treated by flotation or pyrometallurgy, depending on their grades. Hydrometallurgical methods typically entail selectively dissolving the metals of interest (Cu, Co, and Ni) in aqueous solutions (leaching), transferring the dissolved metals to an organic solution, and retransferring these to a second aqueous solution (solvent extraction). Copper and nickel are readily dissolved in an acidic aqueous media. In contrast, cobalt is difficult to dissolve, especially if it is present in the third oxidation state; however, this species becomes soluble after it is reduced to Co2+ (Mwema, Mpoyo, & Kafumbila, 2002; Kime & Makgoale, 2016)."

Jan 1, 2017

By M. Noaparast, N. Nickoletopoulos, André R. Laplante

"This paper presents an application of the use of synthetic ores to study gold recovery by gravity. Three case studies are presented: the first focuses on the use of tungsten to study applications of Knelson Concentrators for upgrading gravity concentrates; the second on tungsten again, in this case to study the performance of a 86 Falcon Concentrator; and the third on lead to mimic gold's grinding behaviour.It is shown that the use of synthetic ores with metallic substitute for gold is not only expedient, but it can also lead to an increased understanding of separation and grinding mechanisms, because of the more accurate results and controlled particle shapes. The case studies highlight the problems associated with gold particle flakiness and gangue density. The grinding behaviour of malleable materials is shown to be complex, as particles can migrate to coarser size classes by flattening and cold welding, and to finer size classes by folding and actual breakage.IntroductionThe title of this contribution is not entirely misleading. Mineral processing has much to do with philosophy, rather Philosophy, as described by Georgius Agricola:""Furthermore, there are many arts and sciences of which the miner should not be ignorant. First there is Philosophy, that he may discern the origin, cause, and nature of subterranean things; for then he will be able to dig out the veins easily and advantageously, and to obtain more abundant results from his mining. ""1"

Jan 1, 1995

By R. B. STEWART

A few days ago, while reading a report of the late Dr. Robert Bell in preparation for this afternoon's meeting, I found some impressive figures concerning the magnitude of the Hudson Bay basin. From the waters of the Bay itself, this great territory extends eastward 500 miles, westward l,300 miles to the Rocky mountains, and southward to the source of the Red river. It has a width of 2,100 miles from east to west, and a length of l,500 miles from north to south. Its area is almost three million square miles. It is not, of course, my intention to review the natural resources of this vast territory, but to confine my remarks to that portion of it adjacent to the waters of Hudson bay. A number of erroneous ideas exist in the minds of many concerning this northern country, especially as regards its latitude and climate. Burwell, at the entrance of Hudson strait, is in the latitude of 60 degrees or roughly that of the north of Scotland. The southern end of James bay has about the same latitude as the northern end of Vancouver .island.

Jan 1, 1928

By John F. Kearney

After World War II Canada?s fledgling iron ore mining industry developed along the ill-defined Quebec / Labrador border near what became the town of Knob Lake and later renamed Schefferville. For about twenty-five years from 1954 to 1982 Schefferville was the epicenter of Canadian iron ore mining and the foundation of the Iron Ore Company of Canada. In about 1982 it all stopped, shut down, the miners moved away leaving behind a mining camp and a ghost town that have sat idle and almost deserted for the past twenty five years. The story looks set to change with new plans to re-establish the former mining operations in the historic mining camp. This paper outlines the proposal to reactivate the direct shipping iron ore operations in the Schefferville mining camp, and specifically the properties in Labrador owned or optioned by Labrador Iron Mines Limited (?LIM?), a wholly owned subsidiary of London Stock Exchange listed Anglesey Mining plc. The Schefferville mining camp is located about 1,000 km northeast of Montreal. There are no roads connecting the area to southern Labrador or to Quebec. Access to the area is by rail from Sept Iles to Schefferville, or by air from Montreal and Sept Iles.

May 1, 2007

By M. Pfeifer, M. N. Brodie, D. J. Barratt

"This paper reviews design trends related to the various SAG mill configuration and drive options available today. The impact of these options on capital and operating costs is assessed, and key technical issues reviewed. The discussion is based on the conventional North American ’pancake’ mill configuration. IntroductionDuring the past decade mill technology has evolved significantly in the following key areas:• improvements in variable speed motors continue with on-going advances in electronics;• ring motors, or gearless drives, are becoming more common in mill sizes 32 ft and larger, with ratings of 10 000 HP and greater;• geared drives have become available up to ratings of 9500 HP per pinion, compared to the earlier 6000 HP guideline;• improvements in speed reducer technology due to the use of carburized and ground precision gearing, make the high speed motor-speed reducer drive more competitive with the direct coupled low speed motor drive;• a unique speed reducer drive is being introduced to this industry which combines ring gear drive pinions with speed reduction. mprovement in gear alignment is claimed, and the overall drive arrangement is more compact than is possible with a conventional speed reducer drive;• the first 38 ft and 40 ft diameter mills have been designed and manufactured; and • application of large multi-shoe bearings have made shell supported mill configurations available for all, including the largest sizes. These designs have flat instead of conical mill shell ends, and have the potential for technical and cost advantages compared to conventional trunnion supported designs.This proliferation of mill design features provides several options to those involved in planning and design of milling plants, and requires more extensive evaluation to optimize mill design features to best suit specific project requirements."

Jan 1, 1999

By A. Mosqueda Martinez, L. C. Trytten, R. P. Kofluk, J. J. Budac

The Corefco ammonia leach nickel refinery treats Ni-Co mixed sulphides from the high-pressure acid leaching of Moa Bay nickel laterite. Due to the low iron content of the feed, the ammonia leach process generates a leach residue with ~10% Ni+Co. Since commissioning a leach residue pressure filtration circuit in 2002, this residue has been stockpiled, dried, and sold commercially. For several years, the residue was sold to nickel smelters overseas. In 2014, re-processing of the residue in the high-pressure acid leach was tested. Lab test work was completed showing excellent extraction of the contained nickel and cobalt, and additional beneficial effects in the high-pressure acid leach circuit. A plant test in Moa confirmed the results, and preparation for shipment of the valuable leach residue for re-processing has begun. This paper outlines the test work and results, and some commercial considerations.

Jan 1, 2015