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By D. W. Rogers

Several commercial polyacrylamide flocculants most widely used in Western Canadian mineral processing plants have been analyzed chemically and compared in standardized settling tests as aids to thickening and clarification. Data are included for both dry and liquid-type flocculants. Percentages of active ingredients in these commercial products varied Widely. Performances were compared on the basis of: equal additions of active ingredients, nearly equal molecular weights and nearly equal degrees of ionic character. Based on zone settling velocities and supernatant clarities of siliceous slurries coagulated by lime additions, dry flocculants proved more economical than liquid flocculants. Using these same two criteria, the most highly anionic were more effective than either weakly anionic or non ionic polyacrylamide- type flocculants.

Jan 1, 1978

By T. Alan O'Hara

"Annual mining revenue can be computed by formulae relating metal prices, smelting schedules, concentrate grade and recovery to known ore grade and an assessment of core samples. Operating costs at different daily tonnages are related to orebody shape, mining method, milling process and general plant services. Capital costs are related to sizing of mining equipment, mine development, plant-site topography, climate and accessibility, plant services and personnel housing. IntroductionA crude guide to the average 1978 cost of mine projects is shown in Figure 1, but the costs of many mine projects have differed widely from the graphed average costs of $800,000 T0.6 for underground mine/mill projects and $400,000 T 0.6 for low-grade open-pit mine/mill projects.High mine project costs and high operating costs are characteristic of open-pit mines with high stripping ratios, underground mines with thin orebodies, mills with complex metallurgy, and projects located in isolated regions with severe climate, mountainous topography, and lacking access to existing roads, towns and electric power. When none of these adverse conditions prevailed, the mine project cost was typically much less than the graphed average cost. Virtually all the conditions likely to cause high capital and operating costs are known from knowledge of the local topography, climate or accessibility, or can be assessed by tests on core samples, as soon as the orebody has been outlined by drilling .A more accurate estimate of over-all project capital cost and operating cost can be made from a summation of items of cost after judging the effect of specific local conditions on each item of capital and operating cost. This paper offers guides in judging the effect of local conditions on the sizing and 1978 cost of specific items of capital cost and operating cost and operating cost of mine projects. When the specific items of capital cost and operating cost are totaled and measured against expected net revenue and taxes over the life of the mine using the net-present-value or discount-cash-flow methods, the result should show whether the mine project development is clearly feasible, doubtfully feasible or clearly uneconomic. If the development of the mine project is clearly feasible, or probably feasible, a detailed feasibility study by experienced consulting engineers should be commissioned before any financial commitments are made; but if project development appears to be uneconomic, the time and cost of a detailed feasibility study is not warranted."

Jan 1, 1980

By Holt. Grover J.

"IntroductionThe history of iron ore production in the United States has followed a pattern not far different from that set in the production of non-ferrous ores; the first interest of the prospector and miner being the discovery and development of high-grade ores. In the early stages of development of most mining districts, high-cost low-grade ores are usually of slight interest due to the additional capital investment required in concentrating plants, as well as the increased requirements of •power and other facilities. As the reserves of higher grade ores are depleted and the technical knowledge of ore beneficiation is broadened, production of concentrates from the lower grade ores is stimulated.The real stimulus necessary to arouse serious consideration of beneficiated iron ore in the Lake Superior district has been provided by the serious inroads made in the high-grade ore reserves by two World Wars.The first shipment of high-grade iron ore from the Mesabi range in Minnesota was recorded in 1892, and the first token shipment of concentrates was made 15 years later, in 1907. Not until 1910 did the production of concentrates assume any great importance. A steady increase in concentrate production over the years is shown by the fact that, in 1910, concentrates accounted for 8 per cent of the total shipments from the State, whereas by the time of World War II this percentage had increased to 22 per cent and by 1948 had risen to 26 per cent. It seems a safe assumption that the shipment of concentrated iron ore, from the Mesabi range in particular, will continue to increase even more rapidly from now on, with other iron ranges of the Lake Superior district following this lead."

Jan 1, 1950

By John Jiang, Brian R. Hart, Stamen S. Dimov, Aparup Chattopadhyay, Barun K. Gorain

"This paper presents a systematic approach to metallurgy diagnostics using an integrated gold deportment methodology developed for complex refractory gold and copper-gold ore bodies. Quantification of gold deportment for these ore bodies is a challenging task due to reasons such as lower grades, high variability of visible and invisible gold content in different sulphides and iron oxide phases, significant presence of disseminated and composite carbonaceous matters along with associations of various copper sulphide phases. Some case studies are presented in this paper to demonstrate the value of a high confidence gold deportment methodology in developing insights for problem diagnostics and to identify opportunities for metallurgical improvements. A holistic approach involving different fields of expertise is critical for successful development and delivery of solutions for complex ore bodies.INTRODUCTION Studies were initiated on various complex ore deposits and also on samples representing various process streams. These complex copper-gold single refractory, double and triple refractory gold ores are mainly composed of silicates and/or carbonates with moderate amounts of clay and mica, along with minor amounts of sulphides and organic carbonaceous matter. Variable proportions of visible gold and “invisible gold” (sub-microscopic gold) were noted in different mineral phases for various ore types and process stream samples. Invisible gold commonly occurs as solid solution or as colloidal-sized particles in different sulphides and other phases for different refractory ores. The dominance of invisible gold and presence of highly preg-robbing along with finely disseminated carbonaceous matters adversely affects gold recovery in flotation and leach circuits for most of these double and triple refractory ores. This paper discusses applications of an integrated gold deportment technique developed for different types of gold and copper-gold ores, namely, complex copper-gold, double and triple refractory gold ores (Chattopadhyay & Gorain, 2014; Chattopadhyay et al., 2016). Various process streams from flotation and gold leaching circuits were investigated. Different concentrates and tailings samples from flotation circuits whereas feed and discharges from pressure oxidation (POX) and carbon-in-leach (CIL) residues were used from gold processing circuits."

Jan 1, 2017

By M. Laframboise, M. Buarzaiga

High-pressure acid leaching (HPAL) of nickel laterites has received considerable attention in recent years. High paymetals extraction, good selectivity, and advances in pressure hydrometallurgical technology are some of the reasons for this interest. Falconbridge Limited (Sudbury. Ontario) investigated the HPAL process using both fresh water and seawater for ore processing. The use of seawater resulted in a chloride concentration of 7.8 g/L in the autoclave feed. A test program was developed to study the effect of process water and leach temperature on the leaching behaviour of different ore compositions from the Koniambo deposit in New Caledonia. The work showed that salinity has a major effect on autoclave chemistry. This paper explores the results.

Jan 1, 2004

By E. Godfrey

The average man one meets on the street thinks of an explosive as a medium of death and destruction, something unstable which should be given a wide berth, because he knows little or nothing about its use or its stability. Briefly, explosives are compounds that develop very large quantities of heat and gas in an extremely short time and in a small space, thereby exerting enormous pressure upon surrounding bodies, and by the rapid expansion of this highly heated gas are able to perform a considerable amount of useful work. The amount of heat generated and the volume of gas produced by the decomposition of an explosive determines the amount of mechanical work it can do, and the time occupied by its change from solid or liquid condition to gaseous condition determines its shattering effect. Explosives manufactured by reputable people are not extremely dangerous, on the other hand they are quite safe if handled in a proper manner. Furthermore, before an explosive can be placed on the Canadian market a sample must be submitted to the Explosives Division of the Mines Department, who may condemn or permit its manufacture, according to their findings regarding its safety in handling and its stability during storage.

Jan 1, 1926

By W. G. Wahl

The Slave Province, a segment of Archean continental crust, migrated west and north from the northern flank of the Superior protoshield shortly after the Kenoran orogeny. The probable cause of migration, the path it followed and the cause of its coming to rest can be inferred from the Bouguer gravity data. The migration caused an indentation in the edge of the Superior protoshield which precluded the development of the Hudsonian orogenic front under Hudson Bay. As the nickel and asbestos deposits of the Thompson Nickel Belt and the New Quebec Nickel Belt are restricted to this orogenic front, no such deposits would occur under Hudson Bay.

Jan 1, 1973

By E. Topuz, C. Duan

"INTRODUCTIONOperations research (OR) applications have experienced a substantial growth within the mining industry during the last three decades. The purpose of this paper is to present a summary of the results of a comprehensive survey of the application of various OR techniques to the major mining activities. It is hoped. through this sur vey , that the most widely used OR approaches, the important areas of application, and future trends have been identified.This survey included more than 500 articles published in this field in English since the late 1950s. Most of the relevant literature was found in mining publications, but, in terms of quality and originality, important applications were also found in literature not related to the mining industry. The sources constituted periodicals, proceedings research reports, and a few books. A listing of selected publications from which three or more articles reviewed in this survey appear is given at the end. Operations Research MethodologiesOperations research is concerned with optimal decision making in, and modeling of, deterministic and probabilistic systems that originate in real-life situation s. One basic feature of the OR methodologies is the attempt to optimize certain design parameters, subject to a set of constraints. This distinction has been employed in the survey as a guideline for selection of the techniques covered under the title "" OR methodologies"". The methodologies thus encountered in the literature are listed below. In a few cases, simulation has not been considered because it is not an optimization method per se."

Jan 1, 1989

By Q. Li

"The precursor of In2O3 was prepared by hydrolysis precipitation/hydrothermal method using In(NO3)3 solution as the feed material and ammonium hydroxide as the neutralizing agent. The crystallinity, morphology and particle size of the products were characterized by SEM, XRD, BET and LPSA. The results showed that the hydrolysis product consists of an aggregate of cubic In(OH)3 particles with a short rod morphology. In the hydrothermal process, the structure, morphology and size of the particles changes through the mechanisms of Ostwald ripening and phase transition, respectively. When the hydrothermal temperature was less than 280 ?, the Ostwald ripening process took place, which changed the morphology of the particles from short rods to cuboids through dissolution-recrystallization. When the hydrothermal temperature was higher than 280 ?, the processes of Ostwald ripening and phase transition took place successively. Firstly, the morphology of the particles changed from short rods to cuboids through Ostwald ripening, and then, the phase transition from cubic In(OH)3 to orthorhombic InOOH occurred and the morphology of the particles changed from cuboids to polyhedron. INTRODUCTIONDue to its excellent electrical conductivity and optical transparency, indium tin oxide (ITO) film has been wildly used in flat-panel display, solar cell, antistatic coating and EMI shielding (Medvedovski et al., 2008). Indium oxide powder is one of the fundamental materials for preparing ITO film. Along with the development of ITO targets of both high density and large size, high quality indium oxide powders, such as single phase, nano-size, spherical morphology and mono-disperse, have been in high demand (Nakashima and Kumahara, 2002; Betz et al., 2006; Kim et al., 2007). The main preparation methods for indium tin oxide or indium oxide powders include chemical precipitation (Nam et al., 2001; Xu and Yu, 2007), melt atomizing-combustion (Chen et al., 2000) and spray pyrolysis (Ogi et al., 2009). Among them, chemical precipitation has been preferred, since it is simple, easy to control and suitable for industrial scale-up. In chemical precipitation method, indium oxide powders were prepared through the following steps: firstly, indium hydrate precursor was precipitated from an indium salt solution by neutralization using an alkali, such as ammonia; and then, indium oxide (In2O3) powders can be obtained from the precursor through calcination (Li et al., 2006), or solvothermal method (Lee and Choi, 2005), or hydrothermal processing/roasting (Xu et al., 2005; Chen and Li, 2007), respectively. However, the indium oxide powders obtained by direct roasting are polycrystalline, dispersable with a wide size distribution (Liao, 2006). The disadvantages of the solvothermal method are high cost, complicated after-treatment processes, as well as bad performances of the powders (Udawatte and Yanagisawa, 2000). Therefore, among three methods of obtaining indium oxide from the hydrolysis precursor, the hydrothermal process/roasting method is the most feasible to synthesize high quality In2O3 powder with uniform crystallinity and size (Kim et al., 2002; Zhu et al., 2004; Xu et al., 2005; Xu et al., 2005; Chen and Li, 2007; Seetha et al., 2009). However, current research on hydrothermal process-roasting method has been limited to the synthesis of a certain ITO or In2O3 powders under specific conditions. A systematic study on the phase transition, as well as the change of the morphology and size of the particles in the hydrothermal process is still missing. In this paper, the effects of hydrothermal processing on the mineralogy, morphology and size of products were investigated. The results showed that the evolution of crystal structure, morphology and size in the hydrothermal process was affected through the mechanisms of Ostwald ripening and phase transition successively. These results are novel and have guidance for improving the hydrothermal process for In2O3"

Jan 1, 2012

By D. G. Cerigo, D. M. Bryce, P. H. Jennings

This paper summarizes the results of an experimental and economic study undertaken to evaluate the feasibility of treating an oxidized orebody of about 10 million tons, grading about 0.75 per cent copper, by agitation leaching and by percolation leaching.

Jan 1, 1968

By David G. Dixon, Ahmad Ghahremaninezhad, Edouard Asselin

"Atmospheric leaching of chalcopyrite in sulfuric acid solutions is a slow process due to the mineral’s passivation. We have investigated the nature of the passive film in this work. Electrochemical reduction and oxidation of chalcopyrite over the potential range of -0.5 to 1.2 VSHE were investigated in 0.5 M sulfuric acid solution (pH 0.3) at 25 ºC by multicyclic voltammetry and open circuit potential measurement. The influence of scan limits on the evolution of current peaks was studied with both stationary and rotating electrodes. It was observed that the anodic oxidation of chalcopyrite begins at potentials above 0.6 VSHE, most likely by preferential dissolution of iron atoms over copper atoms. The selective electro-dissolution process results in formation of a metal-deficient sulfide passive film (i.e. Cu1- xFe1-yS2, y > x). The passive film dissolves at 0.9 VSHE. Elemental sulfur is one of the products of chalcopyrite dissolution above 1.0 VSHE. Cathodic reactions within the potential region of 0.1 to 0.6 VSHE and anodic reactions at potentials lower that 0.5 VSHE are associated with at least one soluble species from solution. The soluble species involved in the cathodic reactions are likely ferric and cupric, while the soluble species involved in the anodic reactions is likely H2Saq."

Jan 1, 2014

By H. Clare Horwood

"Two structures, a fracture zone and a shear zone, contained the two orebodies that yielded all the ore mined at the Gold Eagle mine. The orebodies are known as the Gold Eagle vein and the No. 1 shear zone. Both structures occur close to contacts between Timiskaming sediments, Algoman diorite, and later Algoman granite-granodiorite. The structures were produced by compressive forces from a south direction acting in the southern part of the McKenzie-Gold Eagle stock and in a cylindrically shaped inclusion of Timiskaming sediments.The mine, which exhausted its ore reserves and ceased operations in September of 1941, is on the east side of Mackenzie island, in the centre of Dome township in the Red Lake area.The Gold Eagle vein was located during the summer of 1933 by a surface exploration programme carried out under the direction of Alex Gillies. Sub-· sequent diamond drilling and underground exploration led to the installation of a mill, which came into production in October of 1937. The No. 1 shear zone was discovered and explored later from a drive on the 500-foot level. The mine produced a total of 40,204 oz. gold and 19,157 oz. silver from 223,628 tons of ore hoisted (180,095 tons milled) during its 4 years of mill operation.GENERAL GEOLOGYThe ore-bearing structures trend S.61°E. across Timiskaming greywacke, Algoman diorite, and later Algoman granite-granodiorite. The greywacke is a large, cylindrically shaped mass that is separated from the mai~ mass by the later intrusives. It is a massive, light-coloured, quartzose variety that has been recrystallized by the enclosing granite. The diorite and the granite-granodiorite are early and late components of the McKenzie-Gold Eagle stock. The diorite, which is a porphyritic rock containing large crystals of andesine-labradorite surrounded by hornblende, was injected early in the Algoman period. It was intruded and in large measure surrounded by the later granite-granodiorite. This rock varies from a granodiorite near the mine to a granite in the centre of the stock. All three intrusions are massive and homogeneous."

Jan 1, 1954

By D. A. Nelson, Wedding. R. E.

"A planned production increase of 1.25 million tonnes per year at Domtar's salt mine in Goderich, Ontario required an increase in the underground mine ventilation system from 320,000 to 700,000 scfm, The design of the expanded facility included the addition of a 22-foot-diameter shaft to augment the existing production and service shafts.A preliminary review of the ventilation requirement s indicated that in order to pr ovide good economic design for the expanded system, a comprehensive ventilation survey of the existing system was required. The survey was completed in the latter part of 1980, and subsequent engineering design and equipment selection proceeded throughout 1981.This paper presents the methods used to carry out the survey. Particular attention is given to the numerous challenges presented in determining air flows in the large 45-ftwide by 43-ft-high airways. Emphasis is placed on practical field survey techniques.A mathematical model of the ventilation system using a computer program is described, and the application of this program to provide design data and assist in equipment selection is discussed. Economic sizing of airways and fan selection are analyzed considering horsepower and operating costs.IntroductionThe Goderich Mine of Sifto Salt Division, Domtar Inc., is located on the eastern shore of Lake Huron in the town of Goderich, Ontario, and has been operating since November 1959. The salt is extracted by a modified room-and-pillar method, and the workings advance at a rate of 1.5 miles per year by undercutting, drilling and blasting. The surface mine area consists of a 12-acre site in the Goderich harbour, at the mouth of the Maitland River, and the underground property consists of approximately 2,700 acres lying mainly under Lake Huron."

Jan 1, 1983

By R. Bainbridge

THE cinnabar deposits of the Consolidated Mining and Smelting Company's Pinchi Lake property, situated near Fort St. James, B.C., were discovered and reported on by a Dominion Government geological party in 1937. Claims were staked by a group of local prospectors and, later, the Consolidated Mining and Smelting Company of Canada, Limited, took an option on the property. By the fall of 1939, exploration work had indicated ore of commercial quantity and grade, and laboratory tests had shown that standard methods of reduction, namely, roasting of the ore, followed by condensation of the mercury vapour produced, would result in satisfactory recovery. In June, 1940, construction of a 50-ton unit arranged for wood firing was completed and operation commenced. The installation consisted of a 46 in. by 60 ft. rotary kiln (see Figure 1) followed by a 14-in. Sirocco cyclone, a cast-iron condenser unit, and a 1,700 c.f.m. fan, exhausting to a stack. Other equipment included a 9 in. by 18 in. Denver jaw crusher with the necessary bins and feeders. As the need for mercury was urgent, because of war requirements, construction of a duplicate unit was begun almost immediately. This first extension started operation in January, 1941, and the plant was then capable of treating about 150 tons of ore daily.

Jan 1, 1945

By Barry Hope, Javier Rico

"Goldcorp’s Hoyle Pond mine has recently completed several projects which have impacted the overall ventilation system. The project includes extending the Fresh Air Raise (FAR) to depth, development of a new Return Air Raise (RAR), and the installation of new sensors and ventilation controls throughout the mine. Two years after the completion of #2 Winze, the mine is ramping up its ore production to 1,300 tpd (up from 1,100). To ensure safe and profitable production, a reliance upon technology has been needed to provide the required ventilation to the work areas according to the mine plan. To systematically assess the mine’s ventilation in real-time, a significant increase in remote monitoring was required. This included installing additional flow, pressure, temperature and gas sensors. The first step in upgrading the existing monitoring was to purchase airflow and differential pressure monitors and install them in key areas of the mine. This paper presents the process of expanding the monitoring capability at Hoyle Pond mine, the selected equipment and the results of the implementation. The intended goal was to improve safety while minimizing capital and operation costs. The monitors were installed in strategic locations to provide immediate feedback on the impact of changes to the primary ventilation airflows. Comparing the available sensor technologies, installing them and systematically monitoring the ventilation served as a first step towards developing a mine wide Ventilation Control System. In addition, the initial state of the monitoring and control system, with final results and the chosen solution for the mine site, are presented. INTRODUCTION The Hoyle Pond mine is located in the City of Timmins, within the Porcupine mining district, Ontario, which has produced more than 70 million ounces of gold since 1910. Currently, approximately 60% of Porcupine Gold Mines gold production comes from the Hoyle Pond underground mine. Mechanized cut and fill and long-hole mining methods are used to extract the ore. The remainder of the ore comes from the Hollinger Open Pit mine. The Dome Underground mine ceased operations in 2017. Hoyle Pond is currently mining at 1820 meters below the surface and plans to go deeper. The average dry-bulb as wet-bulb temperature underground varies according to the depth and surface conditions which has extremes of –40°C in winter to +30°C in summer. The total airflow volume pushed down from surface is 240 m3/s to accommodate the diesel-powered equipment needed for normal operations. In order to improve the quality of air underground a program has been implemented to use diesel particulate filters, starting with the truck fleet and 6-yard scoops, followed by the intention to implement the rest of the functional diesel-powered equipment and eventually move to electric equipment."

Jan 1, 2019

By K. Cybulski

Coal dust explosions still remain the main hazard in the coal mining sector, notwithstanding their relatively wide recognition compared to other hazards and the development of effective methods of prevention. Coal dust explosions are still the cause of numerous catastrophes, often leading to fatalities. Fortunately, they rarely occur, and it is for this reason that their hazardous impact is often underestimated. This problem in Poland is being exclusively solved by the Central Mining Institute, Experimental Mine Barbara. Here, basic research on the phenomenon of coal dust explosions and prevention methods is carried out, as well as investigations into the causes and circumstances of past accidents. After 15 years of no coal dust explosion accidents in Poland (1987?2002), a few coal dust explosions have recently occurred, with tragic consequences. These events have taken place not only in hard coal mines, where the presence of dangerous coal dust is the result of common production cycle, and safety measures against coal dust explosions are subject to specific regulations, but also in coal-fired power plants. This is of special concern because prior to 1987, such accidents had been been reported only for coal mines and not for coal-fired power plants. In recent years, two dust explosions occurred in Polish power facilities: the Dolna Odra and Turow power plants. In both cases, coal dust explosions occurred in the fuel supply system, but biomass dust was also involved. The explosions caused significant damage to the systems and buildings. This paper gives description and schematics of the regions of catastrophic coal dust explosions that have occurred in recent years in Poland, as well as the results of post-accident investigations, presenting the coal dust explosion hazard at the accident scene The results specify in detail the state of safety measures against coal dust explosions in light of the relevant regulations in force, including amount of deposited coal dust, content of incombustible matter in coal dust, free moisture content in coal dust, state of coal dust explosion safety zones, and state of explosion barriers. The conclusions from the site inspection and post-accident investigations presented enable us to determine locations of explosion initiation, probable ignition sources, range of explosion flames, and explosion barrier performance. A complete elimination of coal dust explosion hazard at the site of dust deposition is practically impossible to achieve. Similarly, a total elimination of ignition source, which may be related to the occurrence of other natural hazards, equipment malfunction or human errors, is impossible. The examples of tragic events that took place in Polish coal mines and coal-fired power plants highlight shortcomings and mistakes made in terms of assessment and prevention measures taken against the coal dust explosion hazard.

Aug 1, 2013

By N. Schreithofer

The deposition of octadecylamine (ODA) at the KCI crystal/NaCI-KCI brine interface was investigated using atomic force microscopy (AFM). The AFM images of freshly cleaved KCI specimens immersed in KCI-NaCI saturated brine at room temperature reveal disappearance with time of the atomic steps and formation of cubic NaC1 crystals. These crystals were found to form when the specimen was withdrawn from the saturated solution. Depending on the way of contacting the specimens with the octadecylamine dispersion, the AFM images show huge differences in the deposition patterns of ODA on KCI crystals. Adequate dispersion was found to help the formation of quite even ODA coverage. The coverage was several monolayers thicker when air/brine/solid contact took place, suggesting that in the potash flotation the collector is likely to be carried to the solid surfaces by air bubbles. The presence of methyl-isobutyl carbinol (M IBC) enhanced the dispersion of ODA in brine, thus helping the spreading of the surfactant on the KCI crystal surface.

Jan 1, 2006

"5.1. IntroductionThe sample preparation requirements for bulk analyses of platinum-group elements (PGE) are different from the requirements for ore microscopy and in-situ analyses. It is necessary that the initial sample collection results in as representative a sample as possible for both types of analyses. Ingamells (1980) believes, however, that sampling is always imperfect and that there is no such thing as a truly representative sample. Once collected, the usual low content and irregularly dispersed nature of the PGE require that samples for bulk analyses be made as uniform as possible, whereas in samples for ore microscopy and in-situ analyses the PGE must be concentrated. Because of the generally high specific gravity of platinum-group minerals (PGM), certain precautions must be taken, such as mixing the sample material in the bags prior to opening.5.2. Preparation forBulk Analytical MethodsThe principal factors that determine the size of the sample required for a bulk analysis are grade, heterogeneity and grainsize. Initially, the grade and sample heterogeneity can only be estimated and a sampling methodology is developed with experience. It is essential at all times, however, that the assayers have information about the source of the sample and the purpose for the analysis. Information on the grain-size, which can only be obtained through mineralogical analysis, is also very important for PGE analyses, but, unfortunately, is often ignored.5.2.1. Samples fromUnconsolidated DepositsConcentrations of PGE may occur in eluvial deposits as well as in a large variety of alluvial deposits, including those of fluvial and glaciofluvial origin. These deposits are often difficult to map and sampling is further complicated by the wide range, from sand-size to boulders, of the non-POE-bearing constituents, and by the irregular distribution and shape of the ""pay streaks"". PGE concentrations in unconsolidated deposits are largely composed of resistant Pt-Fe and Os-Ir-Ru alloys (cf. Cabri and Harris, 1975 and Raicevic and Cabri, 1976), thus making comminution to the usual-150 to -200 mesh somewhat unreliable, due to the malleability of these alloys."

Jan 1, 1979

By K. M. Deen, E. Asselin

Hydrometallurgical processes, i.e., Cu extraction from a mineral concentrate and Zn electrowinning, are coupled in a battery-like system. A naturally-sourced CuFeS2 concentrate mixed with activated carbon is used as a positive slurry electrode separated by a membrane from the negative compartment. The Zn is deposited on the negative Al current collector from the circulating solution containing 100 g L–1 Zn2+ in 0.2 M H2SO4. In this battery-like system, both CuFeS2 oxidation and Zn deposition are possible during the charging cycle. The additional benefit of this setup is the energy storage if discharged by re-dissolving the Zn in the negative compartment. Cyclic charge/discharge testing revealed oxidation of the mineral concentrate supported by the Zn2+/Zn redox reaction. The coulombic and energy efficiencies increased monotonically to 95.6% and 43%, respectively, with approximately 7% Cu extraction during the first 10 charge/discharge cycles (completed in 2.4 hours). The discharge energy density also increased from 2.7 to 36.2 mWh L–1. In the following 90 cycles, the low energy (~14%) and coulombic (~33%) efficiencies that were obtained confirmed the progress of irreversible reactions e.g. Cu extraction from the mineral concentrate. Overall, approximately 16% Cu was extracted from the mineral concentrate over 100 charge/discharge cycles (or about 12.2 hours). INTRODUCTION Chalcopyrite (CuFeS2) is the main economic copper-bearing mineral, which is generally processed through pyro-metallurgical methods to produce Cu. However, environmental challenges with smelting, depletion of high-grade ores and a large number of impurities (some toxic) have resulted in continued research aimed at the development of hydrometallurgical technologies to process CuFeS2. There are a number of different proposed hydrometallurgical routes in the literature to treat CuFeS2 concentrates, but only a few have attained commercial acceptance (Dreisinger, 2006). Zn is another commercially important metal that is mainly produced via acid leaching of roasted sphalerite (ZnS). The pregnant leach solution is rigorously purified to remove all the soluble metal impurities, particularly those that are electrochemically more noble than Zn and present large kinetic activity towards H2 evolution (Hu & Piron, 1992; Mackinnon, Brannen, & Fenn, 1987; Mureşan, Maurin, Oniciu, & Gaga, 1996). Metal impurities such as Cu, Co, Ni, Cd, Pb, Sb, As, Ge and Fe etc., if they exist in the leach liquor beyond the tolerance limits, can decrease the current efficiency during electrowinning and deteriorate the deposit quality (Alfantazi & Dreisinger, 2001). A complete flow sheet, describing the process steps of Zn metal production from mine site to pure metal is presented elsewhere (Brown, Meisenhelder, & Yao, 1983).

Jan 1, 2019

By J-F. Turgeon, Y. Pépin, G. Hudon

The high temperature hydrochloric acid leaching of titanium slag in the QIT upgraded slag process (UGS) creates a harsh environment for materials of construction. Because of their excellent chemical and heat resistance, furan mortars are a key component in the lining system of the UGS pressure leach reactors. Similar products coming from different manufacturers have however shown unequal performances in service. In some cases, cracking of the brick lining has occurred during curing of the mortar. This study was initiated to investigate the impact of the curing conditions on the properties of carbon filled furan mortars. Laboratory tests were conducted to assess the effects of temperature and exposure to water and HCl solutions on mortar shrinkage and mechanical properties (tensile, compressive and bond strength). Three commercial furan mortars that have been used in the UGS leach reactors were thus characterized. Mortar properties were found to vary significantly among the products tested. Moreover, the curing conditions were shown to have a significant impact on mortar shrinkage and mechanical strength. The experimental findings provide explanations for the unequal performances of the mortars in service and for the problems of brick lining cracking that occurred in the UGS leach reactors. This study demonstrates that excessive mortar shrinkage compromises the integrity of a brick lining system.

Jan 1, 2004