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By A. D. Walters

"IntroductionScreens are used in coal preparation plants for four basic functions, namely:I. Scalping off large size run-of-mine coal for initial size reduction;2. Sizing of coal treatment in different process streams;3. Removal of magnetite (dense medium) from clean coal and refuse;4. Dewatering.Canadian coal preparation plants use screens extensively in the above functions. Even plants where no beneficiation takes place, screening and crushing are carried out in the size reduction process.Description of Process UnitsThe type of screen used in coal preparation plants generally falls into the following categories:Fixed Screens and Grizzlies (for large coal)Often a simple rugged construction, either set horizontally above a bin or inclined with the coal flow.Fixed Sieves (for fine coal)They are used for dewatering and/ or size separation of slurried coal or discard. The sieve bend, the Vor-Siv, the Wilmot riffle and the cross flow screen fall into this category. The most commonly used in coal preparation plants is the sieve bend, Figure 1. Coal slurry is fed tangentially onto a fixed curve wedge wire screen deck. The solids are separated at a predetermined particle size, delivering a partially dewatered overproduct and a dilute underflow. The coal slurry is initially delivered to the sieve bend via a feed box. A series of baffles spreads the feed evenly across the width of the deck. The slurry drops from the last baffle, passes through the feed spout and is fed tangentially to the screen. It is important that the feed should contact the surface immediately at the front end of the sieve bend. It is possible to lose as much as 250Jo of screening area with a poorly fitted screen box.The full stream of coal slurry flowing over the sieve bend decreases in depth, in increments of approximately •;4 the slot width each time it passes a slot. Sieve bends make a size separation at 112 to 2h the slot width. This feature virtually eliminates blinding of the screen surface. Slot sizes are normally quoted in millimetres, available standard slot sizes are from 2 mm to 0.125 mm. The sieve bend is also widely used in coal preparation for preliminary dewatering."

Jan 1, 1989

By S. Balideh

A good understanding of the behavior of rock helps us to make more informed decisions regarding geo-structures. Engineers need accurate equations to calculate the strength and deformation of rock before and after failure. Previous studies explain the failure of rock to ultimate strength, and laboratory tests adequately determine the ultimate strength and deformation modulus of rock. However, there are few comprehensive equations to determine the post-failure strength and deformation of rock. Previous work shows that the post-failure behavior of rock depends on the behavior of the broken rock particles after failure. The following question is then posed: How can the post-failure behavior of rock be determined by the behavior of broken rock particles? In order to answer the question, this study pursues three objectives: (i) to explain the behavior of broken rock at low confining pressure; (ii) to estimate the behavior of broken rock via the extrapolation of scaled laboratory testing; and to suggest a procedure (iii) to outline the post-failure behavior of a rock mass at low confining pressure commensurate with the behavior of broken rock in a rock mass.

Aug 1, 2013

By V. F. Hollister

Four conditions are commonly accepted as being needed for the development of native sulphur deposits in sedimentary rocks : (1) ample sulphate-bearing evaporite, normally anhydritic; (2) proximity to petroleum deposits; (3) a hydrodynamic system of communication between these two; (4) a stratigraphic or structural trap to prevent escape of the sulphur and sulphur -bearing reaction products. When any of these requisites are absent, apparently no significant residual bio-epigenetic sulphur deposit will form. These requirements are, however, satisfied in some areas, which include both the Triassic and Devonian evaporites of northeastern British Columbia.

Jan 1, 1977

By W. S. Dyer

Considerable attention has been paid in recent years to the fire-clay and silica-sand deposits of the Mattagami and Missinaibi rivers and ? to the lignite occurring in them. The fireclay especially deserves this attention; it is of first-class quality; it appears to be widespread; it is the only fire-clay in central Canada, and part of it lies not more than 20 miles west of Coral rapids, to which point steel will be laid this coming spring by the Temiskaming and Northern Ontario railway. Undoubtedly, these clays will rapidly find a place in industry. The fire-clays and the better grades of silica-sand are Mesozoic in age and have been referred to the Lower Cretaceous or Upper Jurassic. Glacial clays and sands and Palaeozoic shales also occur in the same region, but are of little economic value, and will not be dealt with in this paper. Dr. Robert Bell was perhaps the first to discover the clays, since in the Report of Progress of the Geological Survey of Canada for 1877 and 1878 he reported beds of lignite on Coal brook, a tributary of the Missinaibi river, underlain by sticky clay and overlain by glacial drift. In 1880 E. B. Borron (1) discovered an extensive deposit of white sand and clay on the east bank of the Missinaibi river, five miles below Coal brook, and in 1890 (2) he examined the deposit found by Dr. Bell on Coal brook. He recognized that the underlying clays were quite distinct from the glacial clays of the region, and suggested that they might be used for fire-brick if metallurgical operations were undertaken in the region. Somewhat later, J. M: Bell described a deposit of fire-clay and silica-sand on the Wabiskagami river, another tributary of the Missinaibi.

Jan 1, 1928

By Eduardo A. Pérez, Alejandro R. Alonso, Rosa María Luna-Sánchez, Gretchen T. Lapidus

Rare earth elements have been widely used in various sectors, from the aerospace and steel industries, to electronic applications, particularly in displays and batteries for portable devices. The high demand for newer and better equipment, such as cell phones, tablets and lap tops, has increased the consumption of the rare earth elements and at the same time the need for its recovery from electronic wastes. For that reason, the recycling of batteries is important, principally the Ni-HM batteries, due to their elevated content of rare earths elements, in addition to the high concentrations of cobalt and nickel. The current processes are based on dissolution in strong acid solutions (sulfuric acid concentrations from 2 to 4 mol/L), and temperatures from 30 to 90°C. In the present work, electrodes from spent Ni-HM batteries were leached using 1 mol/L H2SO4, in the presence of ozone as the oxidant, where recoveries of 96% for La, Ce and Nd were obtained at room temperature. The separation of Ni and Co from the leach solutions was performed using an electrochemical reactor, after which rare earth elements were precipitated, obtaining a mixture of its hydroxides with impurities below 1%, according to EDS analysis.

Jan 1, 2014

By J. I. Gazzarri

A model of solid oxide fuel cell AC impedance behaviour has been developed and is used to simulate the frequency response of a single cell with and without mechanical damage. The results indicate that the presence of mechanically induced damage within the components of a solid oxide fuel cell can be detected by comparing the frequency response of the undamaged cell with that of a cell in which in-plane cracking or delamination has occurred. The presence of such defects manifests itself as a new semicircle in the Nyquist impedance diagram of the full cell. A parametric study reveals the resolution capabilities of the method in terms of the geometrical characteristics of the defects.

Jan 1, 2005

By X. -G. Chen, J. Qin, K. Liu, D. Racine

"Understanding the thermo-mechanical fatigue (TMF) behavior of materials plays a significant role in the safety design of critical components used in aerospace and automotive industries, such as engine blocks and cylinder heads, which undergo the cyclic change of temperature and stress. However, the cyclic changes of temperature, stress and strain make it difficult using the traditional testing methods to accurately simulate the TMF process. In the present work, the Gleeble® 3800 system was successfully applied to develop a reliable procedure to measure the TMF behavior of aluminum alloys. The modified setup together with the new designed program allows the Gleeble system to precisely simulate the cyclic profiles of temperature and mechanical strain. The novel procedure includes the calibration and verification of the TMF setup to ensure the test validity with Young’s modulus measurement, multi-cycle measurement of the thermal strain and zero stress adjustment followed by online monitoring the TMF cycles. The results of the TMF testing of an AA6061 alloy under cyclic temperatures (60–300°C) and various strain amplitudes (0.2–0.6%) were demonstrated. Its TMF behavior was characterized by the typical hysteresis loops and cyclic stress-strain response.INTRODUCTION The thermo-mechanical fatigue (TMF) behaviour becomes increasing important to evaluate the elevated-temperature properties of materials used as the critical components in automotive and aerospace industries, such as the gas turbines (Hu, Shi & Yang, 2016; Moverare, 2007; Segersäll et al., 2015) and engine blocks (Grieb, Christ & Plege, 2010; Javidani & Larouche, 2014). During the cycles of start-up and shutdown of the engines, these components undergo a complex change of loading. Meanwhile, a dramatic temperature gradient exists on the components due to the cooling system. Therefore, the cyclic changes of load and temperature can give rise to the TMF and may limit the use life of such components (Hu, Shi & Yang, 2016; Javidani & Larouche, 2014; Moverare, 2007). Hence, performing the TMF tests to precisely simulate the cyclic changes of load and temperature to understand the TMF behaviours of materials is playing a significant role in the safety design of these components. For TMF tests, two principal types of cycles are generally employed, including the in-phase (IP) cycle where the load and temperature are at the same phase (i.e. maximum load at highest temperature) and out-of-phase (OP) cycle where the maximum load is applied at minimum temperature (Kliemt, 2012; Miller, 2014). The most significant damage mechanisms in engine components are reported to be OP TMF cycles (Javidani & Larouche, 2014; Kliemt, 2012)."

Jan 1, 2018

By E. W. Mountjoy

THE Exshaw formation is a thin but very persistent black shale unit generally well exposed along the easterly scarp faces of the fault blocks comprising tl1e front ranges of the Rocky mountains. It is over lain by the Mississippian Banff shales and silty shales and underlain by the massive Palliser Limestone formation of late Devonian age. The Exshaw continues eastward under the plains of Alberta and on into Saskatchewan, with little change until it reaches the surface of the Palaeozoic-Mesozoic unconformity. During the summer of 1953, the writer was working- with a field party under Dr. J. L. Usher in the front ranges of the Alberta Rocky mountains. This party, sent out by the Mobiloil Company, conducted a geological survey of Devonian rocks between the towns of Banff and Jasper. The writer helped to describe and map these Devonian rocks and obtained first-hand information concerning the Exshaw shale and its relationship to the underlying and overlying sediments. Additional information was obtained from reference material and from a number of geologists whom the writer has consulted. Grateful acknowledgment is offered to them, to the Mobiloil Company for releasing field information, and to F. W. Beales and W. P. Hancock who helped edit the original paper for publication. Information from areas north and smith of that studied and from bore holes on the prairies is referred to. Localities mentioned may be found in Figure 1.

Jan 1, 1956

By A. K. Verma

This paper provides a brief overview of evolution of deformations, stresses, and pore pressures due to different excavation stages during construction of an URL. Excavation of a rockmass develops a damage zone of finite width around the excavated zone which is associated with changes in permeability and which affects the fluid flow mechanism. In this study, a coupled hydromechanical (HM) analysis has been conducted for a water saturated porous rock mass which has been created by sequential excavation and backfill of vertical disposal pit of an URL. For this purpose, an Atomic Energy of Canada Limited?s in-floor concept for a deep geologic repository suitable for Indian conditions has been used. Changes in rock deformations, stresses, strains and mechanically induced pore pressure in an undrained condition, during excavation, as well as those caused by mechanically induced rock deformations after backfill of the disposal pit, have been modeled. A three-dimensional finite difference tool FLAC3D has been used for the analysis.

Jun 1, 2012

By J. Makgatho, P. Condori, J. Winnett, Fischerm D.

"Palabora Mining Copper (PMC) has two autogenous mills that have been in operation since 1976. The mills were originally designed to treat 30 000 t/d of open cast copper ore in a closed circuit with cyclones. As the ore body went deeper the open cast method of mining was changed to block caving, a consequence of this was the dolerite content (hardest barren material) increased significantly, increasing the production rate of pebbles and thus reducing the milling capacity. In order to cope with the increased ore hardness and to increase mill capacity, a second ball milling stage and pebble crushing were incorporated to the circuit. The above actions created new challenges to the circuit operation and bottlenecks in different areas of the milling circuit.This paper reports the holistic work performed on the Palabora autogenous milling circuit including the implementation of a mill constraint control scheme, the implementation of a pebble removal system from the circuit and a new circuit configuration."

Jan 1, 2012

By Y. Wang

Phosphates and fluorides are used as regulators for the removal of silicates from diasporic-bauxite both in direct and reverse flotation. While using dodecylamine chloride as a collector, micro-flotation studies showed that sodium hexametaphosphate has stronger depressing power on diaspore than on silicate minerals with increasing sodium hexametaphosphate concentration at pH 6.5, but sodium fluorosilicate shows poor depression on diaspore with increasing sodium fluorosilicate concentration at the same pH. Zeta potentials of diaspore and silicate minerals become more negative both in the presence of sodium hexametaphosphate and sodium fluorosilicate. Adsorption density studies indicated that the adsorption density of sodium hexametaphosphate on diaspore is much higher than that on silicate minerals at the concentration of 75 mg/L. FTIR spectroscopy studies show that sodium hexametaphosphate interacted with the Al atoms exposed on the diaspore and silicate minerals surfaces to form P?O?Al bonds through the P02 groups. It is possible that sodium fluorosilicate interacted through F- or [SiF6]2- with silicate minerals surfaces based on the analysis by AES.

Jan 1, 2006

By Åke C. Rasmuson, Mahmood Alemrajabi, Kerstin M. Forsberg, Kivanc Korkmaz

"In the present study the recovery of a Panasonic Prismatic Module 6.5 Ah NiMH 7.2 V plastic casing hybrid electric vehicle (HEV) battery was investigated, separately processing the anode and cathode electrodes. The composition of the electrode materials was determined by total dissolution and analysis using ICP-OES. Nickel is the dominant metal in the active materials (65% by mass in the anode and 70% by mass in the cathode). Most of the rare earth elements (La, Ce, Nd, Pr and Y) are located in the anode active material, whereas only a small amount of Y is found in the cathode material. The electrode materials were further characterized by SEM-EDS and powder XRD. The electrodes were leached in sulfuric acid and in hydrochloric acid under different conditions. The dissolution was followed by taking out samples and analyzing the concentration of REE, Co, and Ni using ICP-OES. The results indicate that the dissolution of nickel could be limited by slow dissolution kinetics of nickel oxide. Further, it was found that light rare earths are lost through precipitation during sulfuric acid leaching with increasing extent as the temperature and sulfuric acid concentration increases. The separation of REE from the sulfuric acid leach liquor by precipitation as NaREE(SO4)2.H2O and from the hydrochloric acid leach solution as REE2(C2O4)3.xH2O have been studied by performing experiments using battery leach liquors. INTRODUCTIONIt is well known that the Hybrid Electric Vehicle (HEV) is becoming more common due to economic and environmental reasons. Batteries are widely used in HEVs’ such as automobiles or larger trucks for transportation purposes. The most common type of battery in these vehicles is nickel metal hydride (NiMH), largely due to Toyota's decision to use them in their popular Prius. More than two million hybrid cars worldwide are running with NiMH batteries, such as the Prius, Lexus (Toyota), Civic, Insight (Honda), and Fusion (Ford). Panasonic manufactures HEV prismatic NiMH batteries that have been used by Toyota and GM (among others), while Sanyo manufactures HEV cylindrical cell NiMH batteries, which have been used by Honda and Ford."

Jan 1, 2016

By Hani S. Mitri

Overhand cut-and-fill mining of narrow vein orebodies inevitably leads to the creation of horizontal pillars. As the thickness of the overlying crown pillar diminishes, stresses build up in the pillar. More often than not, this situation causes an increased level of seismicity and possible pillar burst. One well-known strategy to reduce the hazard of crown and sill pillar burst in cut-and-fill vein mining is that of destress blasting. The paper first reviews the methods used for the monitoring and assessment of potential pillar burst in narrow vein cut-and-fill mining. The influence of horizontal stress, mine depth and pillar thickness on stress build-up in the crown pillar is examined through a characteristic narrow vein numerical model. The paper then presents, with reference to three mine case studies, the benefits of destress blasting and the factors affecting its success as a ground control technique.

Oct 1, 2001

By H. Staton, XPS Consulting & Testwork Services, T. Deng, M. Kelvin

"Lundin Mining’s Eagle Operation, located in Marquette County, northern Michigan consists of a mine and concentrator that processes a Ni-Cu-(PGE) ore. Mine production began in 2014 and is expected to achieve production of approximately 23,000 tonnes of Ni and 20,000 tonnes of Cu per year. The ore is trucked to the Humboldt Mill, where both a Ni and Cu concentrate is produced.XPS Consulting & Testwork Services (XPS) has assisted the team at Eagle since 2013. Prior to start up, the ore was piloted at the XPS lab in Sudbury, Ontario to demonstrate the concentrator flowsheet and establish flotation operating strategy. XPS consulting metallurgists worked closely with the Eagle team during the commissioning of the plant providing troubleshooting, sampling, metal balancing expertise and support. Finally, a series of monthly composites over a 6 month period was submitted for mineralogical characterization to assess plant performance, identify opportunities for improvement and to provide a baseline for the future operation.Lundin’s investment to test the ores ahead of mining and to team with XPS’s experienced mineral processing engineers to help commission the plant has led to the plant achieving concentrator production targets shortly after startup. The commitment to training and implementation of best practices, and a culture where ongoing testing is the norm, puts the Eagle Operation on sound footing for future operation.INTRODUCTIONLundin’s Eagle Mine is a subsidiary of Lundin Mining located in the upper peninsula of Michigan. The mine itself is an underground operation and the ore is trucked from the Eagle mine site 2 hours to the Humboldt mill.The ore is an ultramafic hosted high grade Cu Ni deposit and exists as either massive or semi massive sulphides. The high resource grade of Cu (2.49%) and Ni (2.93%) make this a valuable ore source. (Owen & Meyer, 2013) A metallurgical team was put together by Lundin to ensure the mill was designed and commissioned to optimize metallurgy in the shortest time from this valuable deposit. The commissioning plan targeted commercial production by Q1 2015."

Jan 1, 2016

By H. Salamanca

Recently, the mining industry has become one of the leading target markets for the technology industry as they need to innovate in their productive processes in order to boost productivity, reduce operation costs, increase operation safety, and improve the quality of life of their workers. This work presents the technological developments that HighService has done in different stages of the mining productive processes to include robotic manipulators in their automation solutions as well as the development of new equipment and sensors. The robotic technology integration is presented in different applications such as handling and selection of cathodes in E-W machines, automation of base plate maintenance, automation of cathode stripping machine, and multi-tools handler for liner bolt replacement in SAG mill liner maintenance activities. The proposed solutions show technical and economical viability with low initial investment and short implementation period of six (6) to ten (10) months. The results have been validated in plant, obtaining higher production rates and availability.

Jan 1, 2007

By D. F. Malan

"This document highlights some of the topical problems associated with the design and support of deep tabular excavations in hard rock. The displacement discontinuity boundary element method has been used for at least five decades to analyse stress and displacement distributions around narrow width excavations with complex plan outlines. The assumption is made in most cases that the rock mass surrounding the excavation is perfectly elastic. Although this approach works well to minimise stress concentrations in practice, it has limitations as important parameters, such as the effect of mining rate, cannot be investigated. Recently, a limit equilibrium model has been studied as a means to enhance standard layout design exercises by including an interactive on-reef damage model. This approach can include explicit energy release dissipation computations. A second problem faced by engineers in the mining industry is the evaluation of pillar and remnant stress. The paper highlights two aspects namely the effect of element size in displacement discontinuity modeling on pillar stress and the difficulty to estimate the effect of total closure on the regeneration of stress in old mining areas. Regarding the support of the tabular excavations, current efforts are focussed on providing improved aerial coverage using hangingwall bolting and temporary nets. An unresolved issue is the installation of permanent mesh in low stoping width areas. INTRODUCTIONSince 1886, more than 50 000 tons of gold has been mined in the Witwatersrand Basin of South Africa (Hartnady, 2009). The nearby platinum mines also saw significant growth in recent years and more than 80% of the world’s platinum group metal reserves are contained in the Bushveld Complex of South Africa (Nell, 2004). Apart from the economic aspects, the mines served as an outstanding rock engineering “laboratory” for many decades owing to the deep, tabular nature of the excavations. The period from 1960 to 1980 was especially lucrative in terms of research and world-renowned researchers investigated the support and rockburst problems (e.g. see Cook et al., 1966; Salamon, 1968; Bienawski, 1973; Wagner, 1984). Many of the rock-related problems nevertheless persist up to the present day and this paper explores some of these problems and recent progress. The production of gold declined substantially in recent years (Hartnady, 2009) and well-directed rock engineering research can play a meaningful role to slow this trend. The objective of the document is to highlight critical areas requiring additional research and not to discuss the topics in detail. The reader is referred to the many references for additional information. The paper only focuses on three areas namely numerical modelling, pillar stress estimation and aerial support. Although these are diverse topics, it is included in one paper to illustrate the many unsolved and practical problems associated with deep tabular excavations."

Jan 1, 2015

By L. M. Oshinowo

The incorporation of advanced analysis tools, such as CFD, into the process plant design process has become possible through advances in commercially available computational fluid dynamics software and faster computers. Multiphase modeling is now typically employed in the design phase of process plant design at Hatch. The multiphase models include Lagrange-Euler and Euler-Euler treatment of the multiple phases. Additionally, mixture models with interface-sharpening algorithms are applied to the prediction of free-surface flows in complex geometry. CFD is applied to applications where traditional design rules are not applicable. The additional rigor of CFD modeling in 2D and 3D allows process engineers to come closer to realizing true virtual plant design. The objective of this paper is to outline the benefits and pitfalls in the application of multiphase modeling for rigorous design. Several application examples in the hydrometallurgical field will be presented.

Jan 1, 2005

By H. Kolcz, G. S. Dobby, R. Stratton-Crawley, S. W. Wilson

"The Matte Separation plant at Inco's Copper Cliff Smelter Complex is described. The continuing implementation of flotation column technology in the flowsheet in various applications is reviewed. Comparative studies on 0.038, 0.10, 1.1 and 1.8 m diameter columns have been carried out. It was demonstrated that consistent metallurgical performance was obtained with both pilot- and plant-scale units. Grade-recovery relationships for plant columns can be predicted with confidence from data obtained from test equipment. The work indicates further areas of the flowsheet in which columns present an attractive alternative to conventional cells. INCO’s MATTE SEPARATION PROCESSNickel concentrate from Inco’s Sudbury area mills has been processed in the Copper Cliff smelter for sixty years. Prior to that, Sudbury ores had been smelted directly. Historically, copper-nickel separation from smelter converter matte was achieved by the classical Orford process. In the mid-1940s Inco developed an improved separation scheme based on mineral processing methods, the Matte Separation Process. A generalized Copper Cliff Smelter Complex flowsheet is shown in Figure 1.Iron sulfide and gangue contained in the nickel concentrate are rejected in the smelting-converting process. The molten product, typically containing 50% Ni, 25% CU and 22% s, is cast at about 1000 ºC, into floor moulds and allowed to slowly cool for four days. During this period nickel sulfide (heazlewoodite, Ni,S,), copper sulfide (chalcocite, cu,S) and a copper-nickel metallic alloy precipitate and form a coarse grain structure that is amenable to separation by physical means. The phase chemistry of this system has been described previously by Sproule et al (1). This matte then becomes the feed to the Matte Separation Process.A simplified block flowsheet of the Matte Separation Process is shown in Figure 2. Matte ingots, typically weighing 20 tonnes each, are broken and crushed in a three stage crushing plant to approximately minus 0.01 m and conveyed to the Matte Separation building. Grinding is carried out in two parallel circuits each consisting of a rod and ball mill in series producing a flotation feed which is 65% minus 44 microns. Typical throughput of each grinding circuit is 650 tonnes/day. The metallic fraction of the feed is recovered by magnetic separation. This product, containing about 66% Ni and 15% CU, is a major component of the feed to the Copper Cliff Nickel Refinery."

Jan 1, 1990

By A. Saki, P. Gebski, W. Ying

Industrial smelting furnaces are subjected to significant structural changes and deterioration caused by the conditions under which they operate. The current methods for the structural assessment of furnaces include visual inspections, analysis of thermal data, acousto ultrasonic-echo (AU-E) of the refractory lining and surveying of the key structural elements. Acoustic Emission (AE) non-destructive testing (NDT) technique has proven its capabilities for continuous monitoring of industrial installations and structures. Recently, Hatch Ltd. has been successful in applying acoustic emission for monitoring furnace tapblocks, and expanding the scope of the acoustic emission monitoring to the structural integrity of the entire furnace. The capability of detecting emissions related to the fracture development in the furnace shell, movement of the refractory, electrode arcing, combined with efficient source location algorithms makes an acoustic emission system a comprehensive tool for the real-time furnace integrity monitoring. In this paper the concept of such state of the art system for structural integrity assessment is presented. The initial results of the acoustic emission monitoring together with data analysis techniques are discussed.

Jan 1, 2011

"Le présent article porte sur la diminution des rejets de concentrateurs produits durant l’exploitation et le traitement des minerais métalliques.Le minerai dilué envoyé au traitement a, très souvent, un certain pourcentage du stérile qui affecte directement la rentabilité des opérations souterraines et amplifie l’impact négatif sur l’environnement. Les essais de la séparation du stérile et du minerai effectués en milieu dense sur quelques types de la minéralisation d’or, ont démontré les deux possibilités qu’offre cette technique:• Dans le cas d’un minerai riche, il a été possible de séparer la part importante du toutvenant (minerai dilué contenant le minerai et le stérile) provenant de la dilution, tout en ayant un taux de récupération élevé (supérieur à 96%).• Dans le cas d’un minerai ayant une teneur sub-économique à cause d’une dilution importante, il est possible de produire un concentré ayant une teneur économique à l’entrée de l’usine de traitement, en éliminant une partie du tout-venant.En plus la séparation du stérile peut accroître, en outre, la rentabilité de l’exploitation minière, car le fait d’éliminer la partie de stérile le plus tôt possible diminue certains coûts (transport, traitement et autres). On conclue que la pré-concentration du minerai (séparation du stérile et du minerai) est probablement une seule solution actuellement étudiée qui diminue l’impact environnemental de la mine, sans avoir des conséquences négatives sur la rentabilité de l’exploitation souterraine."

Jan 1, 1997