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By D. Kong, A. Klyashtorin, L. McGilp, I. Wilson

This work reports on applying iron oxide coated sands media in an experimental permeable reactive barrier to remove uranium species from uranium containing water. A field experiment was conducted at the legacy Gunnar uranium mine & mill site that was abandoned in the 1960s with limited to no decommissioning. The flooded Gunnar mine pit presently contains about 3.2 million m3 of water contaminated by dissolved U (1.2 mg/l), Ra-226 (0.4 Bq/l), and minor concentrations of other contaminants (As, Se, etc.). The water is seeping over the pit rim into Lake Athabasca posing environmental and health concerns. Iron oxide coated sands can be used to immobilize uranium species through an adsorption process. Methods for preparation of hydrous ferric oxide sorbents and their supported forms onto silica sands are described. Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (pXRD) were used to characterize the physical-chemical properties of the sorbent. The monolayer uranium uptake capacity (Qm) was estimated through the Langmuir adsorption isotherm. Adsorption kinetic experiments were performed in a lab environment before moving to a field trial. Based on these lab results and the input on field-scale appropriate geometries, a pilot permeable reactive barrier was fabricated and a field test conducted near the Gunnar pit in June 2019. This pilot test provided technical data and information needed for designing a full-scale permeable barrier based on the iron oxide coated sands, which may be applied for in-situ water treatment at Gunnar and other legacy uranium sites.

Jan 1, 2020

By J. F. Hazzard, R. J. Chalaturnyk, C. Khazaei

"Various measurement, monitoring and verification (MMV) techniques are used to ensure the safety of operations in petroleum projects. One of these techniques is microseismic (MS) monitoring of the caprock. A challenge in MS monitoring of caprock is that unlike projects such as tunnelling in hard rocks, the number of recorded events are much smaller and also wide spread through the rock mass which makes interpretation of the physical meaning behind the events very difficult.In this paper, a numerical technique is introduced and validated for coupling a finite difference code, FLAC3D (Fast Lagrangian Analysis of Continua), with a discrete element code, PFC3D (Particle Flow Code). Then, a similar approach is adopted for modeling microseismic events in the caprock. For this purpose, the underburden, reservoir and overburden layers are modeled by FLAC3D. A rather small section of caprock above the reservoir is nulled in the FLAC3D model and substituted by a PFC3D inclusion. The reservoir pressures are then applied to the reservoir section of FLAC3D. Once the FLAC3D cycles, there will be induced pressures in the caprock due to its undrained response to the change in pressures within the reservoir. These induced pressures are transferred to PFC3D as boundary velocities. Then the PFC3D cycles and sends back the boundary forces to FLAC3D. This back and forth process continues until equilibrium is reached. During this process, there will be bond breakages within the PFC3D inclusion that can be regarded as MS events. An algorithm for recording the microseismic energies based on a change in local strains is also implemented. The results are then compared with real data. The effect of injection fluid temperature is also studied. No significant appearance of microseismic events was observed due to injection of CO2 in both cases (i.e. with or without considering temperature). However, this continuum/discontinuum approach seems promising for understanding the microseismic response of caprock in more detail and also using the MS data for validation of geomechanical models."

Jan 1, 2015

By David L. Anderson

"The objective of this paper is to describe the potential impact of inter-provincial competition f or new output capacity on the Canadian potash industry. It will be shown that the ramifications of such actions are potentially severe, especially since the potash industry is one of the few non-fuel minerals in which Canada purportedly possesses a significant degree of market power. More specifically, the paper addresses the impact of possible expansions in New Brunswick, Manitoba and, perhaps, Saskatchewan. The findings suggest that such initiatives could result in substantial excess capacity and the dissipation of monopoly rents. In summary, given the market structure of the industry, it is unlikely that the employment and economic effects associated with industry expansion will offset the loss in national welfare attributable to rent dissipation.IntroductionThe objective of this paper is to discuss the potential impact of inter-provincial competition for new output capacity on the Canadian potash industry. The ramifications of such competition are potentially severe: given that the potash industry is one of the few non-fuel minerals in which we purportedly possess a significant degree of market power(1), it is important that sound supply management practices are followed. However, possible initiatives by New Brunswick, Manitoba and, perhaps, Saskatchewan may initiate an inter-provincial competition which could result in substantial excess capacity and the dissipation of economic rents(2). Given the market structure of the industry, it is not intuitively obvious that the employment and economic effects associated with industry expansion will offset the loss in national welfare attributable to rent dissipation."

Jan 1, 1985

By Glenville A. Collins

IN 1932, Horace Onyett at Oroville, California, built a practical floating washing plant along the general lines as now known, using a 24 in. by 12 ft. trammel; it was fed with a ½ yard dragline bucket, rated then at 200 yards per day. Onyett dubbed his plant a 'Doodlebug' which name has clung to this type of operation ever since. In general, the 'Doodlebug' dredge is the outgrowth of the depression of 1929, wherein many dirt contractors had surplus idle equipment and a few of them ventured to use it for placer mining. Many such plants were impractical and poorly designed and adapted often to locations not suited to the purpose. However out of the general idea came refinements until today dragline dredging has a very definite place in the gold production of the world. Many of the early operators, being mainly contractors without mining experience or technical knowledge of gold saving, geology, or mechanical design, naturally went through stages of trial and error until a workable unit became standard practice. Credit should be given Bodenson Iron Works of San Francisco, who did a notable job of pioneering and building of floating washing plants; also, to Lord and Bishop, contractors of Sacramento, who were among the early operators, and to several others who built and rebuilt their plants until the weak spots were strengthened to take the beating required, and yet deliver a high degree of efficiency.

Jan 1, 1945

By T. Guan, G. Fu, X. Zhou, L. Deng

"One kind of tailings from gravity separation of polymetallic mine contains 0.5–0.8% SnO2. The proportion of –0.037 mm size fraction of the tailings is 37.12%, and the distribution rate of SnO2 is 60.32% in it. For this tailings, two processing technology was carried out. One was felt-shaking table gravity separation in which the concentrate with a grade of 30% SnO2 at a recovery of 10% was obtained. Another was flotation-gravity separation in which the concentrate with a grade of 51.20% SnO2 at a recovery of 51.69% was obtained, but the dosage of collectors was as much as 990g/t. Therefore, the experimental research on the influence of grain size composition on the cassiterite recovery were conducted. The results show that: (1) the flotation recovery of the cassiterite distributed in +0.043 mm size fraction is only 10%, flotation recovery is not suitable for it; (2) a portion of cassiterite distributed in –0.01+0.005 mm size fraction could be recovered by flotation, but the tin flotation performance will be worsened rapidly and the dosage of collectors will be increased due to the increase of the content of –0.010 mm size fraction; (3) flotation processing is not suitable for –0.005 mm size fraction of the tailings. According to the results, a new technology has been carried out, that is discarding tailings by gravity separation-hydrocyclone desliming-flotation-gravity separation processing flow. The processing index is close to that of the flotation-gravity separation processing flow, and the collector dosage is decreased to 360 g/t by this processing technology. And, it has been achieved that the cassiterite slime is recovered economically and reasonably.INTRODUCTIONAs the density of cassiterite is higher than that of gangue, gravity separation is considered to be a low cost, pollution free, and effective process for cassiterite recovery (Wills, 2009). However, cassiterite is a kind of fragile mineral, over crushing is easy to take place and a large amount of slime is inevitably produced in the crushing and grinding of cassiterite. For the cassiterite slime exists in –0.043 mm size fraction, the efficiency of gravity separation decreases sharply. The production practice shows that, for the fine cassiterite, the recovery of tin exists in –0.043 mm +0.010 mm size fraction is about 13% through shaking table gravity separation, and the tin exists in –0.010 mm size fraction is almost impossible to be recovered by gravity separation. If flotation is adopted to recover fine cassiterite, the problems of high reagent dosage, high cost, environmental pollution, and poor economic benefit would take place. Therefore, the recovery of cassiterite slime is a worldwide problem. A key way to increase the utilization of tin resource and increase the economic benefit of tin mines is developing suitable beneficiation process for fine cassiterite."

Jan 1, 2016

By D. Gorc, T. M. Fraser, Z. T. Nikic, R. Pesalj

"Mount Polley is an alkalic porphyry copper-gold deposit of Lower Jurassic age within the Quesnel terrane in south-central British Columbia. The silica-saturated Mount Polley intmsive complex is assumed to be coeval with volcanic rocks of similar composition in the Nicola Group in which it was emplaced. Other intmsions and some of the volcanic rocks in the Mount Polley area are silicaundersaturated and contain feldspathoids.The Mount Polley deposit is characterized by multiple intrusions that vary from diorite to crowded plagioclase porphyry to monzonite. Intmsion breccias are associated with some of the intmsive phases. Abundant hydrothermal breccias occur on the margins and above plagioclase porphyry intmsions. These breccias provide the main host for mineralization and are associated with the highest concentrations of copper and gold. The breccias are subdivided into four distinct types based on the dominant hydrothermal mineral in the matrix. Actinolite breccia is developed in an elongate zone within the core of the Central zone and grades laterally and vertically into biotite breccia to the southeast. Magnetite breccia is irregularly distributed and is relatively sparse throughout the deposit and albite breccia is dominant in the West zone. Pervasive and vein-related alteration correlates with the breccia types. The core of the hydrothermal system at Mount Polley is subdivided into three zones: actinolite, biotite and K-feldspar-albite. The margins of the core zone are overprinted by a discontinuous zone of calc-silicate minerals. This intermediate zone passes outward into propylitic alteration. Mineralization is most prominent within hydrothermal breccias and is generally present as disseminations, blebs within the matrix and abundant veins. Mineralization is associated with a chalcopyrite-magnetite-bornite assemblage in the core of the deposit passing out into magnetite-pyrite-chalcopyrite. Relatively constant copper to gold ratios suggest that both metals were precipitated under similar conditions.Hydrothermal breccias are genetically related to the emplacement of the crowded plagioclase porphyry melt. Crystallization of the melt was probably accompanied by volatile/aqueous exsolution, forming a water saturated carapace. Decompression of the chamber in response to magma withdrawal, fracture propagation and possible fault movement allowed hydrothermal brecciation to occur at the apex and margins of the intmsion. Alteration and mineralization appears to have been controlled by fluids migrating away from the plagioclase porphyry."

Jan 1, 1995

By Törbjorn Naarttijärvi, Bengt Ludvig, Agne Rustan

"Falling rock is one of the major causes of serious injuries and deaths in Swedish mines. The research at the Division of Mining and Underground Construction was therefore directed toward controlled blasting in hard intense jointed rock.The project was started with an extensive literature review. Model tests with a new equivalent model material have been initiated to find ways of improving blasting techniques. The result showed that long cracks arise at the perimeter holes when there is a long time delay between adjacent holes. This led to the theoretical development of a new initiation method with ultra short delays (1,5 ms) f or controlled blasting, called ""Cutblasting"".Full-scale tests have been done at LKAB in Malmberget in hard intense jointed magnetite ore. Four different types of perimeter charges have been tested, namely: tube charges, ANFO mixed with plastic beads, detonating cord and linear shaped charges. Three types of initiation of the perimeter holes have been used, conventional (half-second delay detonators), instantaneous and ultra short ""cutblasting initiation"" (1,5 ms delay). The change in rock strength before and after blasting has been studied with bore hole periscope, vibration measurement and ocular observation of the rock surfaces.Thefull-scale tests showed that ""cutblasting"" with detonating cord in the perimeter holes gave the smallest damage to the surrounding rock. A combination of cutblasting initiation and tube charges are anticipated to give an even better result. A new method of controlled blasting using linear-shaped charges has also been tested, however, this charge type needs further development.The full- scale test also showed that the damage which can be seen on the rock surf ace is about the same for different controlled blasting methods but the not-visual-damage zone varies as much as from 0,1 to 0,7 m.A new classification system for controlled blasting regarding the damage to the surrounding rock has been devised."

Jan 1, 1985

By T. G. Carter

"During the early part of the 1980s, four new surface coal mines commenced operation in the Province of British Columbia. Each represented a major investment in both persons and materials in order to protect this investment in one significant area-the fixed portion of the surface coal handling system-a substantial amount of work was undertaken to ensure that the system was well protected from an outbreak of fire. A great deal of effort in this field had already been made by those coal mines which had been in operation for a number of years and experience gained at these operations was utilized in determining the level and extent of fire protection for the new mines.This paper summarizes the major problems, and suggests some of the methods of solution, in providing an adequate degree of fire protection for surface coal handling systems. It will also discuss the potential for gas and dust explosions together with ways to minimize this potential.The Fixed Coal Handling SystemNote: The word ""fixed"" has been used in its present context to denote that part of the coal handling system where the coal is moved via fixed installations such as a conveyor. It differentiates from that part of the system where coal is moved by mobile equipment.The raw coal delivered to the truck dump will undergo two major processes on its way to the rail load out. The first will be at the coal preparation plant where coal of specified quality will be extracted from the raw feed to the plant. If this coal is of metallurgical quality, and sometimes if it is of thermal quality, it will pass through a thermal dryer where part of the moisture acquired during coal preparation will be removed, i.e. the second process. As the complexity of both the coal preparation plant and the thermal dryer is such as to warrant separate considerations they will not form part of this paper. Each of the processes, however, is generally, housed in its own building, thus, containment of any hazards is usually more attainable than those existing or caused in the rest of the system."

Jan 1, 1988

By D. Racicot, T. Hanel, E. H. Chown

Over thirty plutons in the Chibougamau-Desmaraisville belt were examined briefly in the field and sampled, in addition to the few masses that have been studied in detail. The survey indicates that the intrusions may be conveniently grouped in four main categories, based on their time of intrusion. These are; remobilized basement domes, pre-kinematic intrusions, syn-kinematic intrusions and postkinematic intrusions. Basement domes, as exemplified by the Lappa rent Massif, are composed of migmatized tonalite-diorite gneiss that has undergone at least two periods of mafic dyke intrusion and at least three major deformational periods. The rise of the basement domes was accompanied by extensive mylonitization and the intrusion of syn-tectonic plutons. Pre-kinematic plutons, such the Chibougamau pluton, are diori te-tonalite in composition, and were intruded into the supracrustal pile and partly eroded before the main deformation of the belt. Syn-kinematic plutons occur principally as marginal intrusions bordering the belt (Barlow), or as discrete intrusions along structural highs (La Dauversiere), and are either hornblende monzodiorite or tonalite in composition. Post-kinematic plutons, such as Muscocho, are principally granodiorite and often porphyritic intrusions locally deforming the enclosing rocks. The close relationship between mineralization and high-level intrusions such as the pre-kinematic and some of the post-kinematic plutons is discussed.

Jan 1, 1984

By Yi-Chun Lin

Mechanical/Electrical/Piping (MEP) systems, due to their complexity and diversity, are the most intricate part of building construction. This being the case, Combined Services Drawings (CSD) and Structure, Electric and Mechanic(SEM) drawings can ensure that all coordination issues are resolved prior to construction. Construction companies attempt to apply Building Information Modeling (BIM) to manage and integrate engineering information and solutions efficiently into the CSD and SEM processes to enhance the accuracy of design and the efficiency of review. There are several powerful commercial tools, such as Bentley Navigator, Autodesk Navisworks, and Tekla BIMsight, that can review the integrated BIM model and detect conflicts in systems, and allow planners to correct the conflict issues one at a time. However, for increasing numbers of conflicts, this may be inefficient, and requires them to be arranged in a list according to impact and seriousness before solving them. For this reason, this research implements a module for conflict impact assessment based on rule-based reasoning to classify and weigh conflict impact and seriousness, and highlight the conflicted objects in the BIM system in different colors depending on their conflict type and seriousness during the analysis. This system not only detects and lists possible conflicts and errors, but also sorts them according to the severity of impact and conflict type. Planners can effectively modify the BIM models according to these conflicts as they are listed and visualized in the BIM system. If these conflicts, such as pipeline interference and problems of insufficient space, can be avoided in the early stages of planning, it facilitates the achievement of project objectives in quality, scheduling, and cost.

Aug 1, 2013

By E. M. Yates, H. M. Hamilton

"For the assent of any new mining project it is essential to determine a realistic value of revenue from the sale of concentrates.A description of the market factors influencing the concentrate terms will be presented along with a detailed review of historical terms of a smelter contract for zinc concentrates. OverviewFor the assessment of any new mining project it is essential todetermine a realistic value of revenue from the sale of concentrates.This applies at all stages of assessment through to the final feasibilitystudy. In forecasting revenue for a zinc mine the followingfactors must be considered:(a) mill recovery and zinc concentrate grade;(b) metal price forecast for all payable metals;(c) smelter terms; and(d) other selling costs.Normally, data from test work are used to determine mill recovery and concentrate grade.Market forecasting, and indeed all economic prediction is an inexact science and probably will always remain so. We have our econometric models our input/output models and a lot of other tools. But they are of no help in predicting the unpredictable. OPEC's huge increase in the price of oil was certainly the most dramatic example of this. It had a tremendous effect on the cost of producing most products world wide and on the price of these products. Any forecasts made prior to the OPEC action were obviously proven wrong."

Jan 1, 1994

By I. C. Brown, J. F. Henderson

"IntroductionThe Yellowknife greenstone belt lies along the west side of Yellowknife bay on the north shore of Great Slave lake, some 600 miles north of Edmonton, Alberta. The producing gold mines along the belt include the Con-Rycon and Negus which came into production in 1938 and 1939, and the Giant Yellowknife, which followed in 1948. In addition to these, the Akaitcho and Crestaurum mines are potential producers and there are several promising prospects.Early geological work along the belt was done by A. W. Jolliffe who first recognized a number of great faults, the largest of which is the West Bay fault with a horizontal movement of more than 3 miles. In 1943, A. S. Dadson, following an examination of the Giant-Yellowknife property, advanced the hypothesis that Baker Creek valley was underlain by a series of major gold-bearing shear zones. Subsequent diamond drilling in 1944 bore out the correctness of this view and outlined the great ore-bearing shear zones that are now being developed and mined by Giant Yellowknife Gold Mines. Near the south boundary of the Giant property, the shear zones are cut off by the West Bay fault. This prompted Neil Campbell, District Geologist for the Consolidated Mining and Smelting Company, to make a detailed study of the geology along the West Bay fault in the hope of finding the faulted extension of the Giant shear-zone system on the west side of this fault. In this he was entirely successful. By careful geological mapping he matched several faulted diabase dykes on both sides of the fault and, knowing their dip, determined the horizontal and vertical components of movement along the fault. Subsequent •diamond drilling based on Campbell's work located the presumed correlative of the Giant shear-zone system on the Con-Rycon and Negus properties, where it has been named the Campbell zone or system. At the present time, all production at the Negus Mines property is coming from orebodies along the Campbell zone."

Jan 1, 1950

By G. W. H. Norman

"During the past few years emphasis has been placed on the importance of major faults, fault zones, and associated structures in localizing ore deposition. This interest has developed partly through experience in mining camps in other parts of the world, and partly by the discovery of such structures associated with ore deposits in the Abitibi region, northwestern Quebec. The recognition of these structures has been brought about chiefly by detailed mapping that has been gradually extended along most of the southern gold belt of Quebec and across adjacent parts of Ontario. In the Chibougamau region of northern Abitibi, progress has been made in mapping major faults by using aeroplane photographs with a scale of about 1,000 feet to 1 inch for field mapping. These studies have shown that many large faults occur in the Abitibi region; also that there is a relationship, direct or indirect, between faults and mineral deposition. The faults are, however, of more than one type and age, and this should be clearly appreciated in any planned programme for prospecting this great region adequately.Geology of the Abitibi RegionGeneral GeologyFaults of more than one age and type occur in the Abitibi region. In order to appreciate some of the age relationships of the faults, a brief summary of the historical aspects and major structural features of the geology (fig. 1) is necessary. These historical aspects may be briefly summarized in chronological order as follows:(1) Accumulation of Archæan lavas and associated pyroclastic rocks, either alternating with, or essentially followed by, deposition of sedimentary rocks, and interrupted at least once by local and perhaps regional folding and erosion."

Jan 1, 1954

By G. Wilson

"Satisfactory hydraulic performance of a centrifugal slurry pump is not the only design criterion. If abrasive wear exists the severity of any damage can be reduced and the life of the wearing parts prolonged by selecting the correct pump to suit the conditions of service. This paper is concerned with the design and construction of centrifugal pumps for handling abrasive solids. The wear phenomena due to the slurry being pumped and the materials used to combat abrasive, wear are outlined. The hydraulic design of the impeller and casing and their relationship to wear and the hydraulic radial and axial unbalance are discussed. The prediction of abrasive wear in pumps can not be precise, as many factors are involved - and this is the object of current research."

Jan 1, 1973

By Garth D. Kirkham

The Problem The Don deposit is a series of two sub-vertical zones that pose a number of challenges with respect to modeling and interpolation. The first challenge is that, based on data and observations, the mineralization and, more importantly, the grade is layered or banded and is stratigraphically controlled. The second challenge is that, due to the undulations of the deposit and extreme changes in dip, using a standard oriented ellipse to guide the estimation process is not appropriate and does not result in an estimate that is representative on a local scale. In order to solve this problem an adapted methodology of relative elevation modelling, has been devised to effectively model and estimate deposits faced with these challenges. Relative Elevation Designed for bedded seam and gridded surface With variable dip and vertical grade variability

May 1, 2013

By D. V. Krefting, D. R. Bennett

"The Cyprus Anvil Mining Corporation established a lead-zinc mine and concentrating plant at Faro in Yukon Territory in 1969. Following some 12 years of continuous operation from a single pit adjacent to the concentrator, the company decided to expand operations into two additional areas on the Vangorda Plateau. The two new deposits, known as Grum and Vangorda, are located some 15 kilometres from the existing concentrator.Confirmation of mining feasibility was followed by determination of the most practical and economical method of transporting the raw ore from the new mine sites to the existing concentrator. This analysis was carried out in two phases. The first phase reviewed the feasibility of alternative transportation systems on an 'order-of-magnitude' cost basis. This work identified systems worthy of more detailed examination. The second phase examined the preferred alternatives in greater detail.Initially, operating principles and parameters were established and catalogued. Then, based on these criteria, complete systems were developed utilizing alternative modes of transportation . In the overview analysis, some transportation modes were judged impractical and discarded, 'order-o f-magnitude' costs were developed for other systems and the most costly were eliminated . In the detailed study, the favourable systems were examined in depth which required development of accurate capital and operating costs, consideration of environ- mental impacts and an assessment of intangibles associated with the operation of a new development."

Jan 1, 1984

By M. W. Mikhail, R. J. Mikula

"Funding has been made available through the National Energy Program to build a mobile fine coal treatment plant. The plant is intended f or field application and also to upgrade the existing pilot plant facilities.Western Canadian coals with high proportions of fines (due 10 their friability) cause high losses of fine coal to the reject and in turn reduce the over-all recovery of saleable coal. Eastern Canadian coals with high amounts of sulphur of ten require crushing to fin e sizes to liberate pyrite and therefore need effective and efficient separation of these fine sulphur particles. The difficulties involved in solving these problems are two-fold. One is the reluctance to experiment in an operating wash plant and the other is that laboratory scale testing often cannot be extrapolated to the plant environment. The mobile fine cleaning plant with its ability to operate at existing coal preparation plants across Canada and with its flexibility in implementing flowsheet option s and close monitoring of fine coal circuit variables, is ideally suited to solve these fine coal cleaning problems. The mobile plant objectives are to design and optimize flowsheets, evaluate and improve fine cleaning circuit operations and 10 lest new process monitoring and control equipment.The schedule for construction and the required resources will be outlined along with flowsheet options and the general R&D philosophy of the mobile plant.IntroductionIn relation to coal preparation technology, Canadian coal s can be grouped as Eastern coal, Rocky Mountain metallurgical coal and Foothills high volatile bituminous coal. The eastern coals have high sulphur contents and in some cases require crushing or even grinding to liberate the fine pyrite . Rocky Mountain metallurgical coals often occur in highly sheared seams which have been subjected to rapid coalification. The high friability of these coals means that degradation during mining, handling and processing is extensive and results in large amounts of fine s ranging between 20 and 60% by mass of the wash plant feed. The widely varying geo logical structure and exposure to the elements results in partially oxidized coals which perform inconsistently in the traditional method of fine cleaning by flotation . Foothills high volatile bituminous coals for thermal use are frequently interbedded with soft shales and bentonitic clays. These clays disintegrate during washing and swell, producing large volumes of tailings. The presence of clays in plant circuits, particularly fine circuits, tends to increase the viscosity and may cause deterioration of the fines density separation and increase magnetite losses. In view of the fact that fine coal cleaning is the most difficult aspect of coal preparation , a research program is being established to study the factors involved and to offer some solutions.A recent performance evaluation of Canadian washeries showed that yield losses in the minus 2 mm coal circuits were approximately ten times those occurring in the coarse coal circuits(1). Because 2 mm x 0 coal represents 30 to 70 per cent of the raw coal, these losses can be considerable . The operating and capital costs of beneficiating minus 6 mm coal are about four to five times higher than for plus 6 mm coal. In the case o f minus 2 mm coal the costs are even higher. The economic importance of the fine coal cleaning cannot be over emphasized and as a result, the CANMET R&D program is geared for fine coal beneficiation."

Jan 1, 1984

By Nathaniel S. Scott

Caland Ore Company Limited, a subsidiary of Inland Steel Company of Chicago, Illinois, leased an iron ore deposit from Steep Rock Iron Mines Limited on January 1, 1953.. This deposit lay underneath a lake and was covered with 161,000,000 cubic yards of Jake bottom material, mainly silt. Removal of this material was done on a contract dredging basis. This contract was divided into a plant phase and an operating phase. The plant phase consisted of supplying two cutter-type suction dredges, each with two booster pumps in the discharge lines. All six pumps were centrifugal, had 36" discharges and were powered by 10,000 horsepower electric motors. Peak demand was 59,157 kilowatts. One hundred and forty miles of steel tower line were built to bring power to the site. The balance of the plant consisted of tugs, 12 miles of discharge line, varying from 36" diameter to 42" diameter and attendant land-based equipment. A number of interesting dams were constructed

Jan 1, 1961

By D. Raicevic

After more than 93% of the uranium is extracted from Elliot Lake uranium ores by a sulphuric acid leaching process, the leach residue (tailings) contains small amounts of uranium and radioactive isotopes, particularly radium-226, which is the most serious health hazard. Heavy metal components and pyrite are also present, along with the gangue minerals. Currently, over /000 acres of the Elliot Lake area are covered with these tailings, which contain over five million tons of pyrite. Because of constant oxidation of the pyrite by bacteria (thiobacillus) and the presence of moisture, pyrite slowly generates sulphuric acid, which steadily leaches the metal-bearing constituents from the tailings. The seepage-flows of the dissolved contaminants, although often quite low in volume, have an environmental impact on the Elliot Lake area. Although these seepages are treated and most of the contaminants removed and impounded, a small amount of the radioactive contaminants reaches Lake Huron via the Serpent River. This paper describes a flotation approach for treatment of the Elliot Lake uranium tailings to produce new, decontaminated tailings practically free of pyrite, with radium, thorium and uranium contents considerably reduced. The decontaminated tailing produced, which comprises about 75% by weight of the current uranium tailings, appears to be suitable for mine backfill. Because mine backfilling normally uses about 50% of the plant tailings, the surface storage of about half of the uranium tailings, therefore, would be eliminated by this process. Mine backfilling would also increase the mine production and thus enlarge the over-all uranium resources due to recovery of the ore from pillars. The pyrite concentrate produced from the current uranium tailings would be suitable for sulphuric acid production. The possibility of uranium recovery, and disposal of radium and thorium from the concentrates produced, is now being studied at CANMET.

Jan 1, 1979

By S. Sopher, C. Barsotti

"Inco Gold Company was created in 1987 as an unincorporated business unit of Inco Limited. In 1988, Inco Gold Management Inc. was incorporated to supply management, exploration and engineering services to this unit. The first new project, at Casa Berardi, Quebec, was brought to production in September 1988, less than two years after completion of exploration. For 1989, Inco Gold's exploration and capital expenditures have been budgeted at approximately $94 million, a record level. Inco Gold holds interests in more than 80 precious metals ventures and prospects in Canada, the United States, Brazil, Indonesia, Papua New Guinea and France. The most advanced projects, in addition to Casa Berardi, are at Mineral Hill, Jardine, Montana, where initial production is anticipated in the third quarter of1989, and Crixas in central Brazil, where production is scheduled to begin during the fourth quarter of the same year.BackgroundTraditionally, Inco Limited's mineral exploration has concentrated on nickel and other base metals but since the early 1980s Inco's exploration activity has focussed strongly on precious metals, principally gold. As a result, three deposits have been discovered and developed . In order to accelerate the establishment of a strong gold mining enterprise with its own specific growth and profit objectives, Inco Gold Company was created in 1987 as an unincorporated business unit. At the end of 1988 Inco Gold's share of drill-indicated gold reserves was approximately 14 million short tons containing 3.4 million ounces of gold.At Casa Berardi in northwestern Quebec, one mine is in production and another is planned to open in 1990. Properties at Crixas in Brazil and at Jardine, Montana, U.S.A., were being readied for production in 1989. By 1991, Inco Gold's share of gold production is expected to be 125 000 ounces with a target of 400 000 ounces annually by the mid-1990s."

Jan 1, 1990