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By L. Rodd, C. Walker, T. Koehler

"The energy content of slag represents approximately 80% of the total energy inputs to a laterite nickel electric smelting furnace. Conventional slag handling methods produce only low grade heat and the entire thermal content of the slag is wasted. A heat recovery system proven on BOF slag in the mid 1980's can be adapted to a laterite nickel rotary kiln electric furnace (RKEF) plant. Slag is granulated using a high velocity air jet inside a waste heat boiler to produce slag granules. Granules are cooled during flight via radiation to water-cooled boiler walls and by convection to the granulation air. This system has the potential to recover 80% of the total slag energy in the form of hot air and steam.Integration of the recovered slag energy into the RKEF smelter can be achieved by a number of methods, including the use of preheated air at the ore dryers, kiln or existing power plant. Energy from the slag boiler may be used to reheat boiler feed water from the power plant or to produce superheated steam and generate electricity. The heat recovery system can provide up to 25 - 30% of the total electrical requirement of each RKEF line and a reduction in CO2 emissions of 234,000 tonnes per year.The total cost of slag heat recovery, including CAPEX and OPEX, is $2.5/GJ, which is competitive with using coal when CO2 credits are $18 per tonne. With Clean Development Mechanism (CDM) carbon credits currently selling at €13 ($20 USD) per tonne CO2, there is considerable opportunity for slag producers in regions including South America, Korea, Indonesia and Africa. Increasing fuel costs and more wide-spread legislation for GHG emissions will likely create conditions in which slag heat recovery could generate a favourable return on investment."

Jan 1, 2010

By J. T. Kalala

Particles for heap leaching in conventional circuits are prepared using Cone crushers. Cone crushers are used to crush the ore to the size range between 12-25 mm for heap leaching operations. Leaching from these relatively coarse particles occurs only at the surface and in subsurface regions, which are accessible from the surface by cracks and pores. Since leaching is active in accessible areas, the method of comminution that forms multiple cracks and pores would offer an advantage for heap leach. An investigation was performed in this study to assess if the HPGR forms more cracks and pores than a Cone crusher. X-ray computed tomography (CT) was used to characterize the degree of cracks and pores formed by these two comminution devices that can be used for heap leaching feed preparation. In order to compare the effect of the comminution method on crack network generation, a bulk sample of the zinc ore was crushed by the HPGR at three different pressure settings (45, 95 and 120 bar), the sample ore was also crushed with a Cone crusher for comparison purposes. Products from the Cone crusher and HPGR experiment were then screened into five size fractions ((-25 +19), (-19+16), (-16+9.5), (-9.5+5), (-5+4.75) mm), Subsamples from the ((-25 +19), (-16+9.5), (-5+4.75) mm) size fractions were analysed. The spatial distribution of the crack network of sphalerite particles was characterized using a highresolution industrial X-ray CT system. This paper describes the use of image analysis techniques including image segmentation, which uses a combination of thresholding and other methods to characterize and quantify crack and mineral dissemination in the sphalerite particles after comminution with the HPGR and Cone crusher. The results are validated with those obtained using traditional techniques such as physical gas (with N2) adsorption, mercury intrusion porosimetry, SEM and QEMSCAN.

Jan 1, 2012

By J B. McConnell

The Thompson smelter has three unique features which form the basis ~f its design: fluid bed roasters which treat nickel concentrate filter cake from the mill, as well as the flux, in order to achieve partial desulphurization; the use of electric furnaces for the smelting of the partially desulphurized, preheated roaster product; and the disposal of slag by water granulation and slag slurry pumping. The installation consists of three fluid bed roasters, each feeding an electric furnace. Nickel concentrate is received at the smelter via pipe line. It is thickened and filtered, and the filter cake, together with siliceous flux, is fed through rotary bin feeders and reciprocating double-gate seals into the fluid bed roasters. Air injected into the roasters through club-head tuyeres oxidizes part of the sulphur and associated iron in the concentrate. The heat of reaction dries and heats the charge. Roaster product is recovered from the gas stream in cyclones and from the roaster bed through automatic valves.

Jan 1, 1963

By G. Reuben Yourt

IN 1935, Wright-Hargreaves Mines, Limited, initiated an enlarged programme of ventilation. In the mine, surveys were made from time to time by the geological staff, and improvements in ventilation were effected to accord with progress in mining as greater depth was attained. In the summer of 1938 an engineer was trained in the technique of dust sampling. Instruments and equipment for this purpose, such as konimeter, microscope, furnace, etc., were purchased, and a suitable office, equipped with laboratory facilities, was provided. The full time of the engineer is devoted to ventilation and dust control. On surface, in the mill crushing-plant and in the assay office and sample crushing room, an elaborate arrangement of hoods and exhaust systems has been installed to eliminate the dust. These installations, however, are not described in the present paper, which deals only with an extensive programme of underground ventilation as a method of coping with high dust concentrations, increasing temperatures and high humilities.

Jan 1, 1940

By A. Warczok, C. M. Diaz, A. Bergman, T. Utigard, M. Barati

The world wide consumption of energy is steadily increasing and by 2030 it is forecasted to grow by another 50%, leading to mounting political and economic pressures. For any pyrometallurgical operation, it is therefore paramount to investigate and implement methods to decrease the use of energy. In the pyrometallurgical processing of steel, copper, nickel and other high temperature metals, a large amount of energy is lost in hot off-gases, molten slags, mattes and molten metals. Most of this energy is generally lost during the cooling and solidification steps with very little focus on energy recovery or reuse. In this paper we will quantify how much energy is contained in the various slag streams, then review previous attempts and methods employed to recover some of this energy, and finally evaluate some novel technologies that could potentially be employed.

Jan 1, 2011

By C E. Gordon Brown

Aircraft utilization, weather and cost data are given for three separate projects north of the sixtieth parallel in the Northwest Territories and the Yukon Territory. These operations, carried out by helicopter-equipped geological and prospecting parties, have cost $24 to $30 per square mile, depending principally on the distance from the base. They provide adequate surface exploration of areas with 40 to 50 per cent rock outcrop. A good one-inch-to-one-mile geological map can be made. T HE exploration of the Canadian northland has been given increasing attention by the mining industry during recent years. In many cases, the initial problem is to make an adequate reconnaissance of a large area where existing geological information is meagre. The Geological Survey of Canada pioneered the use of helicopter-equipped geological parties for mapping at a scale of eight miles to the inch.

Jan 1, 1964

By D. A. Karvonen

In 1970, the Government of Saskatchewan instituted a program aimed at resolving the dilemma of excess productive capacity over the market demand which existed for potash produced in Saskatchewan. The two primary elements of the program were prorationing of potash production to market demand and a minimum selling price. The paper reviews the factors, both local and international in nature that led to the introduction of the program. The licensing mechanics and the operation of the program, along with the changes that have been introduced in two and one-half years of operation, are discussed. Attention is given to the results of the controls as they affect the industry and the province. Also discussed is the outlook for Saskatchewan potash in world markets.

Jan 1, 1973

By G. W. Govier

Measurements of the settling rates and the rheological behaviour of heavy media formed of fine suspensions in water of each of magnetite, ferrosilicon, and galena have been made. For media ranging from 1.6 to 2.8 specific gravity the settling measurements gave initial settling rates of from 0.5 to 0.01 ?cm. 'Per minute for magnetite; from 4.0 to 0.8 cm. per minute for galena; and from 35 to 1.6 cm. 'Per minute for ferrosilicon. These measurements indicate the ?relative stability of the suspensions and should be helpful in establishing the useful specific gravity range for each medium. Measurements of the consistency of the media were made with a Fann Model 35 rotational viscometer. Aibnormal or non-Newtonian behaviour was observed in the case of each media, the apparent viscosity being dependent upon the rate of shear or the intensity of motion. Measurements were made over the rate of shear range of 10? to 1,000 reciprocal seconds. The apparent viscosities of the magnetite media ranged from 450 down to 4?0 centipoise at 2.30 specific gravity, and from 2,450 down to 700 centipoise at 2.80 specific gravity. In the case of the galena media, the variation was from 40, through a minimum of 6, to 10 centipoise at 2.20 specific gravity, and from 950, through a minimum of 180, to 450 centipoise at 3.6 specific gravity. The ferrosilicon suspensions exhibited apparent viscosities ranging from 42, through a minimum of 5.6, to 9 centipoise at 1.9 specific gravity, and from 160, though a minimum of 35, to 85 centipoise at 2.8 specific gravity. The dependency of apparent viscosity or consistency upon intensity of motion is considered to be of particular significance in applications of heavy media where the medium is in rapid motion.

Jan 1, 1957

By A. P. Sasmito

It is well known that underground miners are exposed to one of the most dangerous working environments on earth. As mine delve deeper, the geological factor, mine position and climate condition as well as heat generation from mining machine give rise to the mine operating temperature. This, in turn, has an adverse effect on the environment and thus leads to higher operating costs. Careful estimation and design of air flow rate, spray system, cooling load and additional ventilation auxiliary equipment are of importance to ensure safety, comfort and productivity whilst maintaining low operating cost. A computational fluid dynamics simulation approach is employed to examine underground mine ventilation in a 36 m cul-de-sac of tunnel of coal mine. The model predictions in the turbulent range were validated by comparison with published data. Different turbulence models were tested to select one that yields adequate accuracy and is computationally efficient. Effects of the following parameters are evaluated: tunnel geometry, air flow rate and inlet air temperature. The objective of the simulation is to arrive at an optimal strategy for ventilation and thermal comfort at low cost.

Aug 1, 2013

By Nav Dhadli

Tailings from Oil Sands MiningWhat are they? Challenges Solutions Regulatory Environment Definition of the AFD Tailings Treatment Process 2010 AFD Pilot/Demonstration ProgramTechnical challenges Performance and Results Next steps Oil Sands Industry Collaboration on Tailings Technology TAILINGS ?WHAT ARE THEY? Mixture of remaining water and solids following bitumen extraction process Composed of water, sand, silt, clay, small amounts of hydrocarbon (bitumen, solvent, and asphaltenes) A necessary part of production in excavation of oil sands and removal of bitumen

May 1, 2011

By G. M. Dunn

Pressure leach autoclave circuits are employed in the leaching of ores, concentrates, mattes, alloys and intermediates for the recovery of metals into solution. Once the metals are extracted into solution the value metals can be recovered by hydrometallurgical means such as by purification followed by electrowinning, hydrogen reduction, pyrohydrolysis, crystallisation and other unit operations. In many of these integrated flowsheets the pressure leach step is pivotal to the recovery of the value metals from the host material. In an expansion or a new project, a large component of the capital cost can be associated with the pressure leach step and process engineers frequently look for opportunities to mitigate costs. This paper examines a new route for increasing the capacity of an exothermic pressure oxidation leach for sulphide concentrates, sulphide and phosphide mattes and alloys.

Jan 1, 2004

By H S. Ellis

Flow studies have been conducted on nickel-water suspensions in a 1in.-diam., 42-ft.-long transparent lab-oratory pipeline at concentrations of up to 25 per cent, by volume, and slurry velocities of up to 15 ft/sec. The average size of the nickel powder was approximately 150 mesh (106J.L). Three flow regime were noted. At the highest velocities, i.e., above 10 ft/;sec., where the concentration distribution through the vertical diameter was most uniform, pressure gradients could be correlated with the Durand-Condolios equation (7,8). An intermediate region, i.e., from 7 ft/sec. to10 ft/sec., could be distinguished, the lower velocity limit being that at which nickel particles began to deposit. This region was also marked by decreasing pressure gradients, for a given concentration, as the velocity was reduced. The upper velocity limit in this region was also uniquely defined in that the friction factor for any nickel concentration was the same as that for water. In the third regime, below about 7 ft/sec

Jan 1, 1963

By S. P. Chong, N. C. Shih, G. A. Turner

Fine powders, with the bulk of the particle diameters Jess than 10 microns, were aerated so that each particle was, on the average, separated from its neighbours by 1.3 to 2 mean diameters. In this state, measurements were made of the viscosity and settling rate of the powder, and the interfacial tension between it and a moist pellet. From the viscosity measurements, qualitative analogies are drawn between the behaviour of the aerated powder and that of a dense gas near its critical point.

Jan 1, 1970

By D. Fodor

In Romania, there are significant lignite and brown coal reserves hosted by different regions of the country. The most important lignite bearing zone of the country situated in the North ? West part of Oltenia region and which covers a surface area of 2,500 km2 and host a total reserve of 3.0 billion tons of lignite, of which more than 95% can be exploited by open cast method. The paper deals with the existing geological and mining conditions of the zone , the distribution by mining basins and exploitation perimeters, the open cast working technologies and the economic outcomes obtained throughout the time. Years ago, for the improvement of the economic situation as a whole and in each unit, a large production reorganization, technology update and modernization process was started up. There are described the rehabilitation measures of the technological lines and modernization of the equipments of the production flow-sheet, measures developed at present, too and which will still continue in future. There are mentioned the equipments considered, the components under modernization and the economic outcomes obtained so far. At the end of the paper there are presented the future actions for the equipment modernization and perspectives of the lignite deposit exploitation to meet the national economy requirements of solid fuels.

Aug 1, 2013

By L. Bryson, J. H. W. M. Brits, K. Voogt

"The Anglo American Platinum’s Rustenburg Base Metals Refinery (RBMR) has the world’s first full deposit nickel plating tankhouse. Impurities in the nickel electrolyte can induce stresses in the electrowon nickel deposits that could lead to delamination of the deposit. Identifying the impurities that contribute to increasing internal stresses in the nickel deposit is key to successful operation and automation of the tankhouse. Impurities were introduced in the plant electrolyte and the effects on the full-scale nickel deposits evaluated. The impurity-adjusted electrolyte solutions were also analyzed using commercially available bench-scale methods to determine the induced stress. A correlation between impurity-induced deposit stress and full-scale delamination was developed. A direct correlation can now be made between feed quality, i.e. impurity concentrations, and degree of delamination in the plant. This methodology has the potential to rapidly predict the effect of new reagents, upstream process upset conditions and synergistic interactions between impurities on deposit stress and delamination of nickel deposits.INTRODUCTION Nickel electrowinning in sulphate media was first pioneered by Outokumpu in its Harjavalta refinery in 1960 (Saarinen and Seilo, 1985). The original process was very manual with starter sheets plated onto “acid resistant” steel for 36 hours and then manually stripped and cut into sheets which could be inserted into the main production cells for a further 4–5 days. The starter sheet stripping and manufacture process was later automated. The same technology was subsequently implemented on a number of plants around the world. Anglo American Platinum’s Base Metal Refinery (BMR) began nickel electrowinning in the early 1980’s. The recent expansion of Anglo American Platinum’s Base Metals Refinery necessitated the construction of a new nickel tankhouse to achieve two primary objectives. The first to increase the capacity to 32 400 tpa nickel and the second to reduce employee occupational exposure to nickel aerosols. The new tankhouse has been commissioned and is in the process of ramp-up; more details are given by Hagemann et al. (2016). Fundamental to lowering employee exposure to aerosols was automating both harvesting and final handling of cathode. In order to accomplish this a bold move was taken to plate up to 10 days on permanent titanium blanks which are harvested by automatic crane and automatically stripped. The original development work for the plating nickel on titanium blanks over a ten day cycle is given by Bryson et al. (2006)."

Jan 1, 2017

By A. M. A. Mohamed, F. H. Samuel, S. Valtierra, H. W. Doty, A. M. Samuel

"The influence of Fe, Mn, Cu and Mg alloying additions, Sr modification and grain refinement on the microstructure of as-cast and solution heat-treated Al-10.8% Si alloys was investigated using optical microscopy and EPMA techniques. The results showed that the modification effect of Sr diminished with increasing Cu and Mg additions, due to Sr-Cu-Mg interactions. Strontium caused segregation of AlzCu in areas away from eutectic Si regions, and altered the precipitation sequence of the a-Ah5(Fe,Mn)3Siz iron intermetallic from post-dendritic to pre-dendritic, with the phase observed within the a-Al dendrites. Depending upon the alloy Fe and Mn content, a coarser variation (""sludge"") of the a-Fe phase occurred, in the form of polyhedral shaped particles. The AhCu phase dissolved almost completely during solution heat treatment, while Al5Cu2Mg8Si6, sludge, and a-Aln(Fe,Mn)3Siz phases persisted in all alloys, particularly at high Mg and Fe levels. The f3-Al5(Fe,Mn)Si phase dissolved partially in Sr-modified alloys, the dissolution becoming more pronounced after solution heat treatment."

Jan 1, 2006

By Robert Strachanm

The East Kootenay coal-field, situated close to the boundary between the provinces of Alberta and British Columbia, is composed of four small areas locally called the Crow's Nest Pass, the Upper Elk, the Flathead and Crown Mountain, and comprises an area of about 3 78 square miles. From eleven to twenty-five seams have been exposed of two feet and over in thickness, with a total thickness of about 200 feet of coal, and reckoning about one hundred feet to be workable, gives an estimate of coal available of about thirty-seven billion tons. The coal is a high-grade bituminous, occasionally tending towards anthracite, and the majority of the seams furnish a. very good quality of coking coal as well as an excellent steam coal. The coal-field is found in the mountain ranges in long narrow strips. The age of the fonnation and the thickness of the covering beds have had considerable influence on the character of the coal, and lateral pressure and disturbances in the process of mountain-building have wrought great changes. With such an abundance of coal, it has been a disappointment that the East Kootenay field has not figured larger industrially. So far only one portion of the coal-field has been utilized. This is the Crow's Nest, where, in 1898, the Crow's Nest Pass Coal Company commenced development. Access to the coal seams was easily obtained, the mountain creeks having eroded away the covering, and mines were driven into the coal seams. In that year about ten thousand tons of coal were produced from the mine at Coal Creek.

Jan 1, 1924

By R. M. S. Häggblad

The article deals with stabilisation and regeneration of Ce02 and Ce02/Zr02 based Pt water gas shift catalysts, subject to high initial deactivation. The reaction gas species effect on the catalyst deactivation was investigated by H2-TPR. Activity measurements enabled the effect of different promoters, some added to the Ce02 based catalysts and some to the Ce02/Zr02 based Pt catalysts, to be investigated. The catalysts were also characterised by BET and CO-TPR. Deactivated catalysts activity was restored by using various regeneration methods. Of the two selected carriers the Ce02/Zr02 based Pt catalyst showed the highest resilience to deactivation. For the two different carriers, Ce02 and Ce02/Zr02, Wand Re were the best promoters when the catalyst was subject to deactivation. Experiments with Hr TPR indicate a fast initial change in the platinum oxides concentration and composition. The CO-TPR was used to make conclusions about the various regeneration effects of water and oxygen on the catalyst. Finally it is suggested that not one deactivation mechanism is possible and which mechanism that dominates is dependant on the catalyst and the reaction gas composition.

Jan 1, 2005

By O. W. Borgeson, D. K. Honsberger, R. T. Bell

The Scully Mine, situated in the Labrador Trough near the Quebec-Labrador boundary, is one of the world's largest continuous ore deposits. This paper outlines the sequence of the mining operations from the planning stages to the delivery of the ore to the crusher at an average rate of 50,000 tons per day, 7 days per week. The principal equipment required to maintain this production rate includes four 12.\1.1-inch rotary drills, seven 8-cu.-yd electric shovels and a fleet of large haulage trucks. Particular attention is given to grade control, programmed by computer, drilling and blasting techniques and operational aspects inherent with open-pit mining in Canada's North.

Jan 1, 1969

By M. F. Almeida

"Due to the randomness of all factors influencing the sintering operation, a two-stepped procedure is proposed to find the best way of using stocked fines at a plant producing Fe-Mn alloys for the steelmaking industry. The approach is based on the following: (1) predict the result of the sintering operation by establishing the best multilinear regression model using some of the characteristics of the loaded material; and (2) find the best solution under a minimizing cost criteria by solving a linear optimization problem using the regression equation plus constraints on the feed and product. IntroductionSome tests carried out using 20% to 30% of sinter in the material loaded into a 60 000 KVA Tysland-Hole electric furnace producing Fe-Mn alloys for the steelmaking industry indicated: (1) a meaningful decrease in the off-gas temperature and, consequently, a better energy use due to the material higher porosity; (2) more uniform heat distribution as a consequence of the electrode reaction zone enlargement; (3) an improved furnace control resulting in a smoother operation; and (4) a decrease in gas production facilitating the off-gas treatment. For some years, this plant used only the coarse fraction of the Mn ores, thus stocking all the received and own-generated fine particles. In view of the mentioned results, a strategy for increasing the use of stocked fines was formulated, including a step where it was necessary to decide which components and respective quantities should be used in the blends to be sintered (Almeida, 1984).It is well known that several factors affect productivity and energy consumption in sinter production, also influencing the product quality. Raw materials characteristics, namely chemical and size composition, affect permeability to gases and may or may not allow a deeper bed. In general, finer ores decrease permeability, increasing electricity consumption by fans, but due to their higher specific surface area, react more completely with other components in the mixture. For coke granulometry, a compromise must be obtained in order not to burn it too quickly nor to widen the flame front, therefore decreasing productivity. Decreasing coke in the blend also acts in sinter bonding, decreasing its consistency and increasing crushing and return fines. Moisture addition also influences components mixing, pre-agglomeration, bed permeability and, consequently, sintering productivity. Therefore, optimum conditions must be established for both a given sintering plant and the components in the feed (Dawson, 1993)."

Jan 1, 1998