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By C. J. Edmonds

Of the gold mined in Canada over 90 percent is extracted from the ore by the process of "cyanidation". In this process crushed ore is treated with lime to provide "protective alkalinity" and cyanide, usually in the form of sodium cyanide. The gold is dissolved in the cyanide solution, which after further treatments for clarification, is precipitated by the addition of zinc dust. Wastes from the process consist of tailings which will contain cyanides. Water consumption, mill size, effluent quantity and quality are depicted in transparency (1). It should be noted that as far as the wastes are concerned it has been impossible to postulate a typical situation. Variation from the above data will occur. A summary of data from tailings pond effluents is presented in transparency (2). The figures in parentheses indicate the usual range of values for the parameter.

Jan 1, 1973

By K. Wongpreedee

Recovery and recrystallization of Au wire can degrade strength and alter conductivity properties during exposure to elevated temperature. Au Deformation Processed Metal Metal Composites (Au DMMC's) are being developed for electronic applications requiring high conductivity and high strength. This paper discusses the relationships between microstructure, strength, and resistivity of Au DMMC's. It also presents the results of a recent study on the elevated temperature stability of Au DMMC's of several compositions. Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt DMMC samples were prepared by a powder metallurgy technique. All specimens were processed into wire by extrusion, swaging, and drawing. The smallest final diameter of these wires was 120 ?m. Thermal stability was analyzed by electrical resistivity measurements to determine the relation between transformation rates and time at elevated temperature. The extensive deformation used to produce these composites reshaped the initially equi-axed powder into filaments that are 30 to 100 nm in diameter and 16 to 180 mm in length. The small filament diameter confers high strength on the composite. The high conductivity can be explained by electrons flowing parallel to the filamentary microstructure aligned with the wire axis. Using the Avrami and Arrhenius equation relationships, it is possible to predict the times and temperatures needed to achieve various degrees of homogenization. The Au DMMC's were found to have good thermal stability compared to conventional coldworked Au interconnection wires. Although these composites will revert to solid solutions if exposed to high temperatures for prolonged time periods, their relative stability is sufficient to allow them to maintain their twophase microstructure during the anticipated lifetime temperature profiles of many products.

Oct 1, 2003

By P. Langlois, G. Labonté, J. J. Barrett, J. Holmes

"The Voisey’s Bay mill processes a high-grade pentlandite and chalcopyrite ore in a largely pyrrhotite/troilite matrix. From 1994 to 1997, circuit development focused on making a 14% nickel concentrate. When flowsheet development resumed in 2001, the target grade was raised to 20% ni. initially triethylene tetramine and sulfite pyrrhotite depressants were used in a lime circuit, but by recycling process water and the contained thiosalts, the required nickel grade was made without depressants. construction of the mill was fast-tracked, with start-up in september 2005. ramp-up was faster than other recent nickel installations, with tonnage being limited by concentrate dewatering due to higher-thanexpected ore grades.RÉSUMÉ l’usine de traitement de Voisey’s Bay traite un minerai à teneur élevée en pentlandite et chalcopyrite dans une matrice formée surtout de pyrrhotite/troïlite. De 1994 à 1997, le développement du circuit ciblait la production d’un concentré à 14 % de nickel. lorsque le développement du schéma de traitement a été repris en 2001, la teneur cible a été élevée à 20 % de ni. initialement les déprimants triéthylènetétramine et sulfite de la pyrrhotite étaient utilisés dans un circuit à la chaux; cependant, en recyclant l’eau du procédé et les sulfosels qui y sont contenus, la teneur en nickel a été atteinte sans utilisation de déprimants. la construction de l’usine de traitement a été accélérée et elle a démarré en septembre 2005. la mise en opération a été plus rapide que pour d’autres installations récentes de nickel; le tonnage traité étant limité par le séchage du concentré en raison des teneurs de minerai plus élevées que prévu."

Jan 1, 2017

By Vic Casaletto

"IntroductionThe Canadian mining industry is under immense pressure to compete with foreign mine operations. The very survival of the Canadian mining industry is threatened by lower ore grades, environmental pressures, high cost of labour, unfriendly tax laws toward exploration and the increasing cost of new technology. In order to compete in the world market, Canadian producers and their suppliers are rethinking age old customer-supplier relationships in favour of preferred supplier relationships which can improve the profitability and enhance the competitive position of both partners.This paper attempts to redefine partnerships with suppliers in the context of a ""win-win"" objective. It will outline the measurable benefits to both partners through a representative product which highlights the keynote structure of any successful supplier partnership The Status Quo...Mines all over North America are plagued with the same recurring questions, ""Who has the best product for my operation at the lowest price... How do we know a product will perform to a supplier's projections after the sale...What do we do if the product fails to perform as expected?"" These questions have been asked by underground mining operators for decades but rarely have long-term solutions with measurable results been achieved.The LHD industry is one example of the status quo where partnerships will provide large gains toward technological advancement, reducing mobile equipment costs. The underground mining industry is out of sync with their surface counterparts in the open pit business.Partnerships with suppliers in the open pit world are not only a standard practice but a culture which has existed for decades. Open pit operators enjoy concepts which fix their mobile equipment costs for the life of the mine and hold the equipment supplier accountable for performance and fleet economics for 60 000 service hours and longer.Manufacturers are attempting to transfer this culture into the underground mining industry. Figure I illustrates the significance of a capital driven decision."

Jan 1, 1994

By V. I. Peresypkin, A. Y. Lein, N. S. Bortnikov, Yu. A. Bogdanov

"Abstract - The lipid component in hydrothermal deposits of the Logachev vent field, at 14°45_N of the Mid-Atlantic Ridge (MAR) and Broken Spur vent field, at 29°N of the MAR, was studied. Biochemical, gas chromatographic (GS), and molecular mass methods (GC-MS) research established the mixed nature of the organic matter (OM) including phytoplanktonogenous, chemosynthesized lipids, and lipids of questionable origin. Specific local conditions around the sulfide ores of the black smokers (absence of free oxygen and presence of reduced copper, which prevents OM degradation) facilitate the preservation of biogenic material, including bacteria. The main differences between the lipid compositions of the hydrothermal deposits of these two vent fields relate to the variable nature of hydrothermal circulation systems.At the 14°45_N vent field, high-temperature hydrothermal fields are forming due to the reaction of sea water with upper mantle ultrabasic rocks during serpentinization (a deep hydrothermal circulation system). High pressure and temperature (>400°C), a reducing environment and the presence of various metal oxides are favorable for the abiogenic synthesis of CH4 and oil hydrocarbons (HC). At the Broken Spur vent field, hydrothermal deposits are forming above axial crust magma chambers due to the interaction of sea water and basalts (an axial hydrothermal circulation system). Abiogenic synthesis of HC also occurs in this situation, but to a considerably lesser extent."

Jan 1, 1999

By Randolph A. Pax

"The internal operation of a tumbling mill is a very hostile environment and precludes the sustainable operation of internal sensors to measure the mechanisms of charge motion and breakage events. Instead indirect methodologies are required to expand the current understanding developed within a framework of perfect mixing of the mill contents. A number of measurement approaches have been successfully used to explore the operation of SAG mills including strain instrumented lifter bolts, mill shell strain measurement and thermal (energy balance) of operating mills.Early acoustics measurement was developed by Hardinge using a 'microphone' located close to the expected toe location. This signal was an indicator of the mill fill. Improvements were implemented with the use of two microphones straddling the toe location to try to increase the sensitivity of the measurement and reduce ambiguities. Further improvements included a filtered signal indicative of steel interactions. Unfortunately, the mechanisms of signal generation and the complexity of the processes do not provide a consistent signal.In recent years, advanced acoustic measurement using arrays of microphones utilising signal processing techniques have been implemented as SmartNoise and validated on over 30 mills. This paper will discuss the results obtained with signals such as water holdup, mill shell steel hits and two each of the toe and shoulder angles. An estimate of the internal mill component wear rates is also accessible.Advanced acoustic measurements with wide bandwidths when combined with physics models and process understanding has achieved a step change in the understanding of the dynamic internal operation of a tumbling mills on time scales of 80 ms. These techniques have been used extensively on SAG mills, but have also been applied to FAG and ball mills. Acoustic measurement is used for the rapid diagnosis of mill conditions and holistic control for optimisation and stability."

Jan 1, 2016

By J. F. Perreault, J. Paraszczak

"The profitability of an underground mine depends to a great extent on the production cost.Random equipment failures and their consequences have significant influence on the total operating cost of a mining system. Having this in mind, a reliability study has been initiated for loadhaul- dump machines in an underground mine. The main purpose of this study is to identify the critical machine subsystems, determine their failure pattern and help work out an effective maintenance strategy. In the first part of this study, the failure data of diesel powered LHDs, gathered during an I8-month period have been analyzed. For the purpose of the analysis, the machines have been treated as systems comprising seven subsystems connected in series. The most critical subsystems, i.e. electrical and hydraulic, were further investigated, and analyzed by graphical and analytical methods. Different failure distribution models were applied and discussed. Basic Defmitions and ConceptsIn order to avoid confusion, several terms used in this paper are defined below, as compiled by O'Connor (1991). The acronymsBS and MIL-STD stand respectively for: British Standard and US Military Standard.Failure: the termination of the ability of an item to perform a required function (after BS 4778).Time Between Failures (TBF): the length of time between two consecutive failures.Observed Mean Time Between Failures (MTBF): For a stated period in the life of an item, the mean value of the length of time between consecutive failures computed as a ratio of the cumulative observed time to the number of failures under stated conditions (after BS 4778).Maintenance, Corrective: The actions performed, as a result of failure, to restore an item to a specified condition (after MIL-STD-721 B).Maintenance, Preventive: The actions performed in attempt to retain an item in a specified condition by providing systematic inspection, detection and prevention of incipient failure (after MIL-STD-721B)."

Jan 1, 1994

By P. R. Brito-Parada, G. Bhutani

"The physical processes occurring in flotation columns are very complex as they take place at different scales over a range of sizes and multiple phases. Column design and optimum operating parameters are usually obtained from empirical studies and although progress has been made on its numerical modelling, most column models rely on simplifications that do not fully capture the hydrodynamics. In particular, Computational Fluid Dynamics (CFD) models of the pulp phase in flotation usually assume the bubble population to be monodispersed. While this assumption may be reasonable in some situations, the polydispersed nature of the gas phase can have a significant impact on the predicted flotation rates.Techniques to model size distribution do exist in the literature and have been rigorously analysed in the past two decades for bubble columns, which are very similar to flotation columns from a hydrodynamics point of view. In fact, available CFD models of flotation columns are an extension of bubble column models, sometimes including additional equations for solids treated as passive scalars. This work focuses on the development of an efficient CFD model for flotation columns. The bubble size distribution in the column has been modelled using the Population Balance Equation (PBE), which is solved using the Direct Quadrature Method of Moments (DQMOM). Coupled with the PBE, the multiphase flow equations in the column have been modelled using the standard Eulerian–Eulerian approach. The solution of this coupled system has been made tractable in this work with the implementation of a highly parallelised adaptive-mesh finite element method. This powerful framework has been implemented in the open source CFD code Fluidity and it allows the carrying out of detailed simulations of flotation columns in 2D and 3D, with important implications for industrial column evaluation and design."

Jan 1, 2016

By A. de Ville d’Avray, G. Guezennec, P. Wavrer, E. Braak

The aim of the European CEReS project was to develop an innovative copper recycling route based on the coprocessing of coal production waste by bioleaching and printed circuit boards (PCBs) from Wastes of Electrical and Electronic Equipment (WEEE). Coal waste is processed by bioleaching in stirred tank reactors, and the resulting bio-lixiviant solution is used to extract copper from PCBs pre-treated by catalytic cracking. Copper is then extracted using solvent extraction, stripping and electrowinning. The whole process flowsheet combines thermal, biotechnological, physical and hydrometallurgical operations. Once the process concept has been validated at laboratory scale, a simulator of the whole process has been built in the USIM PAC software platform. The tool enables to improve the analysis of the results of the lab-scale experiments and to design industrial-scale scenarios by simulation. The results of such simulations allow to estimate the economical interest and to perform environmental impact assessment. After presentation of the CEReS project objectives and main results, the paper describes the methodology used to build the simulator and define the scenarios corresponding to feasible process routes. The main results of the simulations are then presented with technical, economic and environmental point of views. INTRODUCTION Because of rapid technological innovations in the electronics industry, electronic waste represents the fastest growing waste stream in the world, especially in developing countries (Işildar et al., 2018). Meanwhile, the global copper demand is expected to go on rising in the future. As significant amounts of copper are present in end-of-life printed circuit boards (PCBs), it becomes a necessity to develop efficient copper recycling routes. Metal refining from e-waste is traditionally performed by pyrometallurgical processes. However, the hydrometallurgical processing of PCBs, which has been shown to be technically feasible at laboratory scale with a wide range of leaching reagents, could be a less energy intensive and more flexible alternative (Tuncuk et al., 2012). However, a large amount of leaching reagent is required to leach the metals from PCBs.

Jan 1, 2019

By Robert E. McIvor

"Use of the Bond Work Index to size industrial grinding equipment was widely known. Bond also described its application for measuring grinding circuit efficiency. Bond Work Index efficiency also has been used extensively by industry, but until now without concise standard methods, or a formal guideline, for doing so. The Bond Efficiency Sub-Committee of the Industrial Comminution Efficiency work group of GMSG has produced such a guideline, which is appended hereto. It covers the methods and provides examples of how to calculate the Bond Work Index Efficiency of most industrial grinding circuits. Bond Work Index testing equipment and methods are also provided.Comminution is responsible for a major portion of mineral processing plant energy consumption and operating costs. Bond Work Index efficiency provides valuable means, first, for benchmarking one’s plant performance against others in the broad industry, and hence defining the extent of the opportunity for improvement. Secondly, improvements in circuit efficiency with implemented changes can be quantified and monitored as part of continuous improvement efforts. These two important business activities are thus facilitated, and, in the absence of any other accepted method, otherwise would be lacking without the existence and application of this standard for comparison. While often loosely applied in the past by plant metallurgical staffs, the increased precision offered by this guideline provides much clearer definition of both the conceptual and statistical meaning of these measurements. Even a small improvement can be enormously financially important, but only if differentiated by measurement. This guideline was thus intended to provide industry improved means to differentiate comminution circuit efficiencies. Carbon footprint reduction is coincidental, but nevertheless can be substantial.The next steps are: (1) to establish standard reference testing materials and one or more laboratories to serve as bases for reference testing; (2) to establish the accuracy of relative circuit Work Index Efficiency determinations; and (3), to develop and provide a public data base of industrial comminution circuit Bond Work Index Efficiencies."

Jan 1, 2016

By Hans Lundberg

The magnetometer which was developed during the war for detecting submarines has proven exceedingly valuable in outlining deep-seated structures in oil exploration, and will be useful also to geologists in outlining regional structural features in the Precambrian. Our magnetometer has been developed to outline local and detail structures. 1 am quite sure that all geophysicists and geologists would agree with me that, in ore prospecting, it is important to obtain as much detailed information as possible. We know that, as we ascend from the ground and get away from the magnetic ore-bearing structures and orebodies, the magnetic intensity decreases rapidly, but, worse than that, we lose the details even faster. Figure l shows two strong, very sharp, magnetic 'highs' over two orebodies which, as our distance increases, rapidly merge into one fairly broad, moderately strong anomaly. If we drilled on this maximum, we would not encounter any of the orebodies. Therefore, we should fly the airborne magnetometer as close to the ground as possible in order to duplicate the results of the magnetic ground surveys. The first chance to accomplish this came with the helicopter, which is an exceedingly maneuverable aircraft. It can be landed in a cleared space not much more than fifty feet square. With floats, it can be landed anywhere, even in a swamp, on thin ice, or on soft snow. It can stand still in the air, hovering over a given point. It can ascend and descend vertically, fly sideways and even backwards, at the will of the pilot. It flies forward at any speed up to l00 miles an hour. The helicopter can be taken to any desired position at a given time. It can fly at any useful altitude from a few feet to several thousand feet above the ground. It can fly very close to the ground with safety. In bare areas, the survey flight may be performed a few feet above the ground. In forested areas, however, the flights, to clear the trees, must be made at l00 to 150 feet. To mark out a certain point, a small parachute-like marker may be draped over a tree or laid on the ground. This can be done from the helicopter without touching the ground.

Jan 1, 1947

By N. Aydogan, H. Dundar, Å. Partapuoli, A. Fredriksson, P. Wikström, K. Tano, G. Adolfsson

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By Min-Sung Kang

Excavation and earthmoving equipment mostly operate in accident-prone areas. These areas normally have rollover, confinement, and fall or may be considered harmful work areas due to demolitions and sewage removals. It is inevitable that excavation and earthmoving systems should be developed to secure the safety of operators through unmanned and remote control systems. Therefore, this research proposes a system that enables excavators to be unmanned and remote controlled without any renovation, remodeling, change, or transformation by applying attachable and separable mechanism and modules. Moreover, this research proposes the sensor module to evaluate the dynamic status without processing remodeling or transformation the existing hydraulic drive excavation system by adopting the easy attachable and separable mechanism. The study verifies this proposal based on observed possibility and feasibility through the experiments.

Aug 1, 2013

By Y. Wong

The quality and quantity of secondary deposits, which include tailings streams and tailings dams, are increasing around the globe. The tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of CAPEX & OPEX. The most widely used process for the recovery of these valuable ultra-fine haematite iron particles is the Wet High Intensity Magnetic Separation technique, originally developed by Dr. Jones over 55 years ago. Many of the original machines are still working today. The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test works, design- and engineering works. Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a Tailings Storage Facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power- and water consumptions, capital requirements and projected operating expenses. The results show that the operating costs are significantly lower than the mining and processing operations which are required for an equivalent amount of iron ore. The recovery % of iron depends on various factors but is within the 30–50% range, at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process. The processing of secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the mine life and offer environmental benefits by reducing the tailings footprint and water usage.

Jan 1, 2016

By H. Perez, A. Lavoie, V. Prévost, P. Létourneau, P. Lind

The Home smelter is a custom copper smelter located in Rouyn-Noranda, Quebec. In 2005, the smelter produced 145,000 t of copper containing 807,000 oz of gold, 20,388,000 oz of silver in addition to 515,000 t of sulphuric acid. Recently, a flexible flow sheet has been developed incorporating the intermittent use of the Noranda Continuous Converter allowing for the increasing or decreasing of production based on market conditions, while attaining 90% or greater sulphur fixation regardless of operating mode. For 2006, the smelter is operating in full production mode and production is expected to be approximately 185,000 tm of copper. Mechanical modifications, process changes, metallurgical concepts, minor element treatments, and operational techniques that have allowed the smelter to develop this flexibility are presented. Current efforts to increase the productivity of the converter aisle and anode furnaces as well as improvements being made to address fugitive emissions are also discussed.

Jan 1, 2007

By M. Maldonado, P. Olivares

"A submersible sensor for real-time gas holdup measurement in the collection zone of industrial flotation machines is introduced. The working principle is based on the generation and measurement of a pulp flow using a gas-exclusion cell immersed in the aerated slurry. The gas exclusion cell consists of a variable-area open vertical tube designed to be filled only with pulp by preventing gas bubbles entrance. The higher density of the fluid column within the cell generates a downward flow of pulp; the rate of this flow is proportional to the gas holdup outside the cell. The gas holdup measurement is achieved by tracking the velocity of the pulp flow leaving the gas-exclusion cell, using a magnetic flowmeter. Construction details of a prototype and its testing in two- and three-phases are discussed.INTRODUCTIONFlotation process optimization consists of finding and maintaining operating conditions that maximize flotation performance measured in terms of recovery and grade. The selective separation of mineral particles proceeds in two interactive zones where different and simultaneous phenomena take place: in the collection zone, the valuable particles are separated by collection on the surface of bubbles, while in the froth zone, the bubble-particle aggregates are gathered, drained to remove entrained particles, and taken into the concentrate stream. The cell overall performance, which can be determined from proper stream sampling, is a function of the recoveries in the individual zones. These zone recoveries cannot be independently measured nor calculated from operating variables. Progress in the assessment of these recoveries has been slow because on-line and reliable sensors to measure properties of the drastically different dispersions existing in both zones are not available.In the case of the collection zone, it has been demonstrated that the recovery of hydrophobic particles on the surface of bubbles, considered as a process with first-order kinetics, correlates with the bubble surface area flux (Finch et al., 2000; Hernandez, et al., 2003; Lopez-Saucedo et al., 2012). Bubble surface area flux (bubble area generated per unit time and cell cross-sectional area), is a variable affected by gas flow rate, bubble size distribution, and frother type and concentration. Gas holdup (volumetric fraction of gas dispersed in the slurry) is also affected by the same variables, and as such, carries information on the interacting variables that define the performance of the process. Therefore, a correlation between gas holdup and bubble surface area flux was expected and demonstrated (Finch et al, 2000), and since gas holdup is easier to measure as no bubble size is required, it has the potential to be the basis of a cell control and optimization strategy if a continuous sensor is available."

Jan 1, 2016

By J. D. McFarlane, V. Robinson

"The paper begins with a brief account of the naturarly occurring resources of gypsum and anhydrite and a discussion of their relative value and utility as sources of sulphur. The fundamental chemistry of recovering sul-phur values from calcium sulphate is discussed. (a) Thermal decomposition -discussed as impracticable; (b) Reduction to calcium sulphide; (i) Total Reduction-The chemistry is outlined and the Dorr-Oliver and Bureau of Mines processes mentioned. The Elcor process is mentioned and certain deductions made from available information.(ii) Partial Reduction-This is stated as the basis of the only proven process, namely ""The Cement -Sulphuric Acid Process."" The possibility of recovering lime is mentioned as an aside, but dismissed for lack of commercial application. The history of the cement -sulphuric acid process is covered briefly and a list of plants in commercial operation included. A brief elementary account of the basic chemistry of cement production is followed by a discussion on raw materials and fuels. A short account of the flow scheme of a typical plant, with notes on the operating peculiarities, precedes an account of product quality. The latest developments which enable by-product gypsum to be used as a raw material are discussed, with an indication of how the flow scheme is modified. A statement of feasible plant capacities is followed by requirements of raw materials, services, labour, etc., and finally some indication is given of capital costs."

Jan 1, 1969

By Renato Macciotta

The argillaceous formation known as the Opalinus Clay is host to the Mont Terri Underground Research Laboratory. The URL was developed to investigate the hydrogeological, geochemical and geotechnical properties of the formation. Underground excavations at the site are characterized by non-elastic and time-dependent deformations. Excavations trending perpendicular to the strike of the bedding presented relatively minor deformations, however, tunnels parallel to the strike of the bedding showed much larger non-elastic deformations. This paper presents an analysis of the measured response of a tunnel trending parallel to the strike of the bedding in Opalinus Clay. The measured convergence is compared to tunnel experience in weak rocks to assess the tunnel stability.

Jun 1, 2012

By A. Miura, R. Winarko, D. B. Dreisinger

Chalcopyrite leaching in acidic ferric sulfate media at ambient temperature exhibits slow kinetics and poor leaching efficiency, which is typically attributed to surface passivation. Recently, the presence of small amounts of iodide in the leaching media has been reported to significantly accelerate chalcopyrite dissolution. To further explore the behavior of chalcopyrite leaching in the presence of iodide, it is essential to determine the factors that control the leaching kinetics. In this study, we investigated the effect of initial solution potential, iodide concentration, particle size, and temperature on the kinetics of copper extraction from chalcopyrite. The key in the experimental setup was to minimize iodide loss by iodine evaporation and precipitation as cuprous iodide. The former was achieved by performing the leaching tests in fully sealed leaching systems. The latter was achieved by maintaining the solution potential higher than 420 mV (versus Ag/AgCl electrode), where formation of CuI precipitate is possible. The experimental results show that higher solution potential and higher iodide concentration had a pronounced positive effect on the rate of chalcopyrite dissolution. There was no effect associated with particle size, which might be due to the narrow size range tested. The positive effect of increasing temperature only manifested itself when the solution potential was sufficiently high. INTRODUCTION The main challenge of chalcopyrite leaching using ferric ions as the oxidant at ambient temperature is the slow kinetics and poor extraction. The reason for this leaching behavior has been attributed to passivation resulting from formation of insoluble passivating layers on chalcopyrite surfaces, which could be metal-deficient sulfides, elemental sulfur, polysulfides, and iron precipitates (Klauber, 2008). To overcome passivation, technologies using higher temperature and pressure have been developed to leach chalcopyrite concentrates, such as the CESL process (Mayhew, McCoy, Mean, & Woeller, 2013), FLSmidth Rapid Oxidative Leach (ROL) process (Mulligan et al., 2017), Galvanox (Dixon, Mayne, & Baxter, 2008), Albion process (Hourn, Turner, & Hourn, 2012), HydroCopper (Hyvärinen & Hämäläinen, 2005), TPOX (Dreisinger, 2006), and AAC/UBC process (Dreisinger, Dempsey, Steyl, Sole, & Gnoinski, 2003). Even though they are effective in accelerating copper leaching kinetics, those technologies typically have higher capital and operating costs associated with production of concentrates and application of autoclaves. This makes them unsuitable for treating low grade primary copper sulfide ores.

Jan 1, 2019

By D. A. Brown, C. Lowe

"Abstract -A multi-sensor (electromagnetics, magnetics, gamma-ray spectrometry, and VLF) geophysical survey was recently conducted in the Purcell Basin of southeastern British Columbia in an area encompassing the world-class Sullivan Sedex deposit. The purpose of the survey was to geophysically characterize the known mineral occurrences and to develop strategies to enhance future mineral exploration in the basin. Follow-up investigations of geology and measurements of rock physical properties helped constrain interpretations of the geophysical data sets.Despite extraction of more than 90% of the ore from the Sullivan deposit, it is clear that the mineralization there, as well as at other Sedex occurrences surveyed, is characterized by high conductivity values, strong bedrock conductors, and elevated magnetic anomaly values. The albite-sericite alteration which accompanies this mineralization yields high potassium and low thorium-potassium ratio values. Associated Moyie gabbro is characterized by low electrical conductivity and radioelement concentrations and by high magnetic anomaly values. The study has also aided exploration for other mineral deposit types including stratabound Cu-Ag, placer gold, vein and disseminated basemetal deposits. In addition, the geophysical data have helped constrain geological interpretations of the basin."

Jan 1, 1998