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By Guangdong Institute of Resources Comprehensive Utilization, Y. H. Tang, H. X. Hu, T. S. Dong, Z. H. Zhang

"A world class rare metals ore deposit in Africa belongs to a massive granite type poly-metallic pyrochlore-niobium resource. Successful project development in realizing the resource is vital to Africa’s economy and pyrochlore processing technology.The ore properties are quite complex due to the presence of varieties of valuable minerals, fine dissemination and intimate association of minerals and the relative abundance of easy-floatable minerals. The separation of pyrochlore from zircon, calcite and mica is generally considered difficult. Whilst studies have previously been conducted by several independent institutions overseas, no satisfactory process has yet been developed to date for the ore deposit—possibly due to the process designed being too complex; high cost of regents; lower performance.Based on process mineralogy study and extensive testwork, the authors have in recent years developed a new technology—“De-slime—Iron-rejection—Zircon (with calcite) and Calcite reverse flotation—Pyrochlore flotation”. The flow-sheet is characterized by ?1prior removal of slimes and iron minerals; ?2 Zircon (with calcite) and Calcite reverse flotation; and ?3Pyrochlore flotation applying new type of chelating collector GYX3 developed by GZRINM in conjunction with selected regulators and depressants.The process involved in the new technology is simple to implement and facilitates stable operation; the flotation reagent regime is easily adaptable; the cost of main reagent is lower largely because it is easy to manufacture and is environmental friendly. Laboratory test results demonstrated that, for raw ore assaying 0.35% Nb2O5, 0.03% Ta2O5 and 0.45% ZrO2, pyrochlore concentrate grade of >35% Nb2O5 could be obtained with >74% recovery. Meanwhile, the Ta2O5 content in pyrochlore concentrate could be recycled, and ZrO2 recovery >50% could be achieved in zircon concentrate assaying ZrO2>63%—significantly improving the technical-economic indicator. These results were verified in pilot trials of 1.44t/d throughput. The paper presents the new technology in whole, summarizes the key factors affecting its performance and discusses in simple terms the mechanism of separation."

Jan 1, 2016

By S. Fabich

Since the very beginning of Polish copper mining, special consideration of sink shaft techniques through highly saturated Cenozoic rocks was required. Shaft freezing has been chosen as a method to consolidate these rocks. Due to the rock mass structure and water inflow potential, shaft sinking without freezing was considered dangerous. In the course of time, rock mass freezing technology and experience were evolved and this technology became safer and more reliable. New techniques appeared not only in the technical method of freezing, but also in the matter of designing. Computer aided techniques allow engineers to make a detailed analysis and view of freeze wall development. Nevertheless it is important to determine basic thermal rock properties. In this paper, the evolution of knowledge and engineering experience taken in Polish copper mines and current knowledge level in that matter were shown.

Aug 1, 2013

By Forrest A. Kerr

Introduction During recent years the work of the Geological Survey in northwestern British Columbia has been in the nature of reconnaissance and exploratory mapping, largely for the purpose of gaining knowledge of the potential mineral-producing zones known to occur along the eastern side of the Coast range, and also to gather such data as might facilitate their exploitation. Commencing with fairly detailed mapping in the more accessible parts, the work has been continued and expanded until now an understanding has been gained of the more general features of a continuous section along the range for a distance of about two hundred miles. Geographically, northern British Columbia is more or less isolated. It is cut off from the central part of the Province by a rugged and mountainous country which, except for the telegraph line and a rarely travelled trail along it, is not penetrated by any developed routes or lines of communication. To the west, it is cut off from the Pacific by the Coast range, an extremely rugged area sixty to eighty miles in width which, except along the few navigable rivers cutting across it, cannot be readily traversed. Politically, it is further isolated in this direction by the narrow strip of south-eastern Alaska which borders the coast and extends inland to the axis of the range.

Jan 1, 1931

By Joseph D. Martinez

"The benefits of modern technology can readily be identified with energy availability. A clear correlation has been established between per-capita energy consumption and the GNP for various nations. The United States is an outstanding example of a nation which has benefited from vast energy reserves. The nation is now challenged, how¬ever, by dwindling reserves and the need to develop new sources consistent with the preservation of environmental quality. The development of new, virtually inexhaustible and environmentally acceptable sources cannot be expected for several decades. Meanwhile, we will have to depend on coal, nuclear energy and/or rigorous conservation measures.The net effect of environmental considerations has been to delay and perhaps ultimately eliminate the nuclear energy option as a national energy alternative. This forces a more positive move toward coal as the next major source of electrical power. Our coal resources are large, but the use and production of coal is also a threat to the environment. Thus, we seem to be moving from one major accessible source to another due to environmental concern only to face the probability that the alternative is also environ¬mentally unacceptable.Controversies revolving about energy choices must be resolved by an analysis of the relative benefits and impacts of these two sources and others. The pattern of changing energy sources is not new. We have moved from wood to coal to oil and gas in the past and must learn to adapt in the future. Rational decisions must be made relative to the utilization of intermediate energy sources pending development of promising future approaches. A collapse of current levels of energy supply could threaten our technological society and the means to develop a new energy base."

Jan 1, 1976

By K. A. Clark

A meeting between representatives of the Scientific and Industrial Research Council of Alberta and the Deputy Minister of Mines for Canada was held at Edmonton in May, 1929, for the purpose of formulating a co-operative plan for carrying forward studies in aid of the development of commercial methods for utilizing the bituminous sands of Alberta. It was agreed that to the Alberta Research Council should be allocated the general problem of investigation of the processes for the separating of bitumen from the sands, including studies of methods of emulsifying, dehydrating and otherwise preparing separated bitumen for industrial applications. It was further agreed that during the present year the work of the Alberta Research Council should be to continue its laboratory investigations of points of design of its separation plant; to further perfect its separation procedure; to recondition its existing separation plant at Dunvegan Yards, Edmonton, in the light of laboratory studies and to operate it for the purpose of demonstrating its efficiency; to carry on tests in emulsifying and dehydrating or otherwise preparing separated bitumen for industrial application; and on the basis of the experience gained in the operation of the preliminary plant at Dunvegan Yards to prepare and design and, as far as possible, to proceed with the erection of, a semi-commercial separation plant at a site to be chosen, probably at the bituminous sand deposits near McMurray, Alberta. This paper presents, in the main, a progress report of the carrying out of this programme.

Jan 1, 1929

By D. G. F. Hedley, F. Grant

"In 1958, the Ontario Department of Mines appointed a committee to study the accident situation and mining methods used in the uranium mines in the E1liot Lake district. This committee reviewed the existing knowledge on mine design, pillar support and roof spans and came to the conclusion that scientific knowledge had not yet reached the stage of producing rational design procedures which would reduce the dependence on trial-and-error methods. Since that time, the Mining Research Centre has made numerous stress measurements in two mines to define the pre-mining and pillar stresses. A comprehensive series of tests has been done in the laboratory to measure the compressive strength of the rock; a geological survey of the region has been made to evaluate tectonic stresses; and a survey was done on mining conditions with regard to stable and unstable pillar configurations. This information has been used to evaluate pillar design as effected by pillar width and height, depth below surface, extraction and pre-mining stress fields. The resultant design of pillar widths and corresponding extraction as the depth increased is in line with past and present experience in these mines. The information available on roof stability is still insufficient to design stable stope spans with the same degree of confidence; experience and trial-and-error methods are still required."

Jan 1, 1972

By W. A. Bain

"AbstractProduction from the Excelsior Reservoir has amounted to approximately one million barrels. This production has caused a 'Pressure •drop of 10 p.s.i. from the original pressure of 1,245 p.s.i.g. Volumetric balance calculations indicate that the pool as being produced by a water drive whose strength is •probably unsurpassed in Western Canada. It has also been shown by 'unsteady state' calculations that the reservoir will still be above the saturation pressure of 915 p.s.i.g. at the time of depletion. The average permeability of the producing formation is approximately 1,000 millidarcys and, consequently, well draw-downs are very low. The field is essentially a bottom-water drive and calculations have shown that gravity drainage will greatly assist the recovery of oil. Water flooding data on several cores •have placed the flushing efficiency at •approximately 50 per cent, which indicates a recoverable oil-in-place of 17.7 million stock tank barrels. Calculations and field data indicate that the MER for the early life of this field is probably as high as 8,000 to 10,000 stock tank barrels per day.IntroductionTHE EXCELSIOR NISKU oil reservoir is located about twenty miles northeast of Edmonton. The field was discovered in November, 1949, by Imperial Excelsior N.o.1 well, in Lsd. 13, Sec. 3, Twp. 56, R. 22, W. 4, at a depth of 3,850 feet.Since discovery, development has continued on a 40~acre spacing pattern. At the end of 1951, drilling over approximately 80 per cent of the estimated productive area of 1,680 acres had established 32 we1ls capable •of production. The field •has been fairly well delineated by dry holes on all but the eastern flank ."

Jan 1, 1952

By Glenville A. Collins

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

Jan 1, 1945

By H. L. Cameron

Introduction Since the beginning of gold mining in Nova Scotia in the year 1860, the biggest problem o the mine operators has been to find and follow the ore zones in the narrow quartz veins. It was early recognized that all veins were not gold bearing and that, in those that were, the commercial ore was confined to limited zones. A large number of geologists and mining engineers have been interested enough to give time and thought to the problem, but, until the last four or five years preceding World War II, they were handicapped by lack of exact data from mining operations. The necessary data could only be obtained by daily checking of underground operations. Such daily checks were instituted at a number of mines during the period 1935-40 and, in every case, were successful in delimiting the ore zone or zones for the particular mine. The present paper deals with the results of this work as applied to practical ore finding. It is an attempt at extrapolation, from observations in the four districts with which the writer is personally familiar, co other districts in which similar conditions or structures are reported.

Jan 1, 1947

By A. Desbiens, A. Pomerleau

During the summer of 1994, a new PID-based control strategy was installed on line B of the grinding circuit at the Kidd Creek Division of Falconbridge Ltd. Part I of this paper described the methodology used to select the appropriate control strategy using a phenomenological dynamic simulator. Part II presents the implementation of the control strategy. Prior to the controller installation, it was necessary to solve various problems related to the process, such as a cyclic behaviour of the rod mill feed tonnage, a problem related to the mill water source and the calibration of the flowmeters. Once these problems were solved, the control strategy was accomplished in two steps. Step 1 corresponds to the installation of control loops to regulate the pump box level and the cyclone overflow density. Step 2 describes the implementation of a loop to control the cyclone feed density. According to Part I, a loop to control the circulating load is also part of the original design. However, reasons are given to explain the rejection of this loop. For both steps, technical procedures such as filtering, process identification and controller tuning are detailed. Finally, the operator’s interface is briefly described.

Jan 1, 1997

By H. Westengen

The AE alloy family exhibits remarkable combinations of properties when utilized as high pressure die castings. This performance relies on the fact that the rapid cooling rate resulting from the direct contact between the molten alloy and the steel die walls effectively refines the structure through rapid solidification. Furthermore, the rare earth additions modify the solidification pattern, dramatically reducing the solidification interval. A solid shell forms at temperatures exceeding 500C, reducing the tendency for die sticking and inverse segregation. As a result, the die castability is excellent, giving parts with a smooth and shiny surface. Unlike other magnesium die casting alloys developed to improve elevated temperature creep properties, AE alloys do not suffer from the commonly observed tendency to introduce brittleness. This feature is attributed to the fact that the massive magnesium- aluminium intermetallic phase is substituted by a finely dispersed lamellar structure of Al-RE intermetallics. The resulting combination of excellent elevated temperature properties and good ductility, as well as excellent corrosion resistance, means superiority of these alloys for demanding automotive engine and chassis applications.

Jan 1, 2006

The Red Lake greenstone belt is an irregular mass of lavas sedimentary rocks and intrusives which is approxiately 35 miles long 18 miles wide and 7 miles deep. Basaltic volcamcs are the oldest rocks w1thm the belt. They are believed to have been laid down on an ancient crust which is at least 3 billion (3 x 109) years old and was composed partly of sediments. The basaltic rocks are overlain by acid volcanics and sedimentary rocks which have been complexly folded and are preserved as a down-folded remnant of younger rocks within the older crust. The volcanics and sedimentary rocks of the greenstone belt have been cut by intrusives with a wide range of composition. The emplacement of the intrusives and the accompanying regional metamorph-ism which terminated the orogenic activity in this area are believed to have occurred approximately 2.4 billion years ago. The basalts and many of the basic and ultrabasic intrusives undoubtedly had their source in the sub-crust or mantle. At least some of the granitic intrusives are believed to have had

Jan 1, 1965

By A. S. Baillie

THE subject of taxes appears to engage our attention altogether too lightly. At least it would seem that, notwithstanding the increase in the cost of government, and its concomitant increased taxation, little constructive work is being done with a view to solving the problem of increased taxes. I believe that the inattention of the public generally to the subject of increased taxation is due largely to the fact that shareholders are not advised of the amount of taxes paid by industry. Were companies to advise their shareholders the amount of monies paid or payable out of each year's earnings for taxes in one form or another, and were such amounts compared with the amounts available for distribution to shareholders, the effect would be a general demand for more equitable taxation methods. While I am not unmindful of the burdens and inequities in taxation confronting industry generally, I believe that the mining industry in this Province does not fully appreciate the burden represented by the costs of taxation. My reason for this belief is based partly upon1the fact that no serious effort has so far been made to devise some means By which the mining industry in British Columbia might protect itself against the ever-increasing burden of taxation. In addition to this fact the widely diverse nature of mining in British Columbia makes the accumulation of comparable data a problem which, so far as I can ascertain, has never been attempted in a manner which would be authoritative. It should not be necessary to cite the effects of this burden upon any one mining company or upon any branch of the mining industry, such as coal mining, placer mining, base-metal mining, or the precious-metal mines. In my opinion, the operation of our mines by large corporations is conducive to the payment of taxes with much less protest than would be the case were the taxes being taken out of the earnings of just a few partners or a very few shareholders. We appear to be too unmindful of the taxes, paid by mining companies, of a kind that are not so prominently brought to our attention as are the taxes which are calculated upon the taxable income of the company at the end of its fiscal year. British Columbian mining companies pay many other taxes besides those which are calculated upon taxable income. Among these are school taxes, property taxes, gasoline taxes, mineral taxes, coal royalty, to say nothing of fuel-oil tax, sales tax, and excise taxes.

Jan 1, 1935

By J. Mirza, E. Nicol, J. Lipkowski

Gold passivation in thiosulfate leaching media is a major barrier to its implementation. Addition of Cu (II) into the leaching solution has shown to aid in gold dissolution, but the mechanism by which it acts, and its role in the passive layer, remains unknown. Surface Enhanced Raman Spectroscopy (SERS), in tandem with linear sweep voltammetry, were employed to determine the dependence of leaching currents on mass transport and for fingerprint identification of sulfur species on the surface of gold. SERS leaching experiments were performed using gold nanorod electrodes that showed increased stability compared to other SERS active surfaces.

Jan 1, 2011

By N. A. Jabit

The dissolution behaviour of ilmenite in acid solutions has been studied by many researchers to improve the leaching efficiency. Most studies which utilized natural ilmenite from different origins resulted in different reactivity due to the alteration caused by the weathering process. Previous researchers have suggested that the greater reactivity shown by some ilmenite samples towards sulphuric acid may be a result of the mineral being relatively unaltered. In the present study a rotating synthetic ilmenite disc of 2.2 cm diameter was subjected to leaching studies in hydrochloric acid. The dissolution rates of iron and titanium from synthetic ilmenite were determined in hydrochloric acid solutions (4 M to 9 M) over a temperature range of 50 to 80°C. Results show that the rate of dissolution of both iron and titanium increased with the increase in acid concentration. However, the rates decreased with time and obeyed a parabolic rate law indicating the blockage of the surface by an insoluble product. The rates of dissolution of both iron and titanium were higher in the presence of SnCl2 and remained unaffected with time indicating the reductive role of SnCl2 which inhibits the formation of surface blocking solids. Application to natural ilmenite is also discussed.

Jan 1, 2014

By Seshadri Seetharaman, Nurni N. Viswanathan, Haijuan Wang

The present work aims at some process modifications in specified metallurgical processes, wherein CO2 can be used successfully as an oxidant for decarburization in steelmaking and applied in some non-ferrous metals production processes. During the decarburization of Cr-containing high alloyed steels, the present researchers investigated the possible use of CO2 instead of Ar-O2 mixture and could successfully decarburize the steel melt without significant loss of alloyed Cr to the slag phase. A mathematical model was developed based on the bubble formation accompanying the chemical reaction: C(molten steel)+ CO2(gas)= 2 CO(gas). The model predictions were tested by laboratory scale (1 kg) experiments carried out in an induction furnace and very good agreement between the model predictions and experimental results were observed. A national project has been sanctioned in China for the implementation of CO2 in decarburization of ferroalloys as well enable the addition of pig iron in the electric arc furnace process when the scrap supply is limited. New processes have been developed for the utilization of CO2 in the case of non-ferrous processes. A novel method of treatment of Al dross by leaching with water and capturing the evolved NH3(formed by the hydrolysis of AlN) has shown very promising results.

Jan 1, 2015

By Andrew Dobson, Cheryl Allen, Enrique Acuña

"Totten Mine return air raise was designed with two parallel fans equipped with silencers to reduce the noise emitted from the outlets into the environment. As development and production of the mine progressed through the past years, the silencer system needed to be upgraded, and additional maintenance strategies have been necessary to meet the regulatory noise limits enforced by the province of Ontario. The current mine plan will require the fans to reach the upper limit of their capacity by Q1 2019. To achieve this operational target, additional silencing capability has been required and Totten Mine has explored alternatives to further extend the noise silencing capacity available considering the current constraints at the mine site. The alternatives included a new silencer baffle design and a new layout that have allowed doubling the length of the silencer system. Using acoustic measurement data collected on several occasions, this paper presents and discusses the performance of the various silencing systems which have been installed on the return air fans at Totten Mine.INTRODUCTION Vale Canada Limited’s Totten Mine is a base metal, underground mine extracting nickel and copper, situated in the Sudbury Basin of Ontario. The mine initiated operations at the end of 2013, and is equipped with two main return air fans and two main fresh air fans located on surface. Both fresh air and return air fans are set in a parallel arrangement to operate as integrated units and are equipped with variable frequency drives (VFDs) to allow for the remote modification of their operating set point, usually between 600 to 880 rpm, depending on the mine’s requirements. The main return air raise (RAR) fans are also equipped with dissipative baffle silencers to attenuate the noise emitted to the environment. Approximately four years ago, acoustical measurements conducted to verify compliance with the applicable regulatory criteria, and respond to noise concerns from neighboring residents, concluded that the sound emissions of the main return air raise exceeded the noise design parameters. The acoustic tones of the fans were audible offsite, at a residential location, approximately 9 km northeast of the mine site. The elevated sound levels and offsite audibility was due to degradation of the original discharge silencers from moisture and particulate being drawn from underground workings and passing through the silencer baffles. The audibility was also due to an outlet directivity pattern which directed noise towards the residential location."

Jan 1, 2019

By John C. Lyons

"The Wabana iron ore deposits occur as flat-dipping beds of oolitic hematite and chamosite, of Lower Ordovician age, which outcrop for 3 miles along the northwest coast of Bell Island, Conception Bay, Newfound-land, about 16 miles from St. John's.The deposits occur in three zones, Upper, Middle, and Lower beds, separated respectively by 30 feet and 215 feet of shale and sandstone. They are primary sediments laid down in a shallow tidal basin by the precipitating action of a marine environment on iron-rich fresh waters flowing into the basin.The ore-bearing zones, while of wide areal extent, are not uniform beds of hematite that can be mined wholesale. The action of waves and currents during sedimentation; the delta pattern, velocity, and transporting power of streams flowing into the basin; the contours and oscillations of the sea bottom on which the sediments were laid have all been fundamental in the emplacement of richer and thicker mineable sections, and of lean zones so intercalated with shale as to be unmineable.The preservation of the deposits is due to their location in the Conception Bay syncline and to a considerable upthrust of the country east of the bay in post-Ordovician time.The hematite deposits were first recognized as such in 1892, and soon after were acquired by the Nova Scotia Steel and Coal Co. They are now being mined by Dominion Wabana Iron Ore, Limfred, a wholly owned subsidiary of the Dominion Steel and Coal Corporation, Limited. Production started in 1895, and up to the end of 1955 totaled 58,588,516 long tons of hematite ore, having an average dry analysis of about 51 5 per cent iron, 11 8 per cent silica, 0·9 per cent phosphorus, and l ·5 per cent moisture. About 40 per cent of the total tonnage mined has come from surface stripping and on-shore mines. These areas have now been almost completely depleted, and operations are confined to submarine mines extending for two miles off shore under the waters of Conception Bay. Three sub-marine slopes are currently in operation, Nos. 3 and 4 working in the Lower Bed and No. 6 in the Middle Bed. A general picture of the workings is shown in isometric projection in Figure 1. Submarine mining has been entirely by the room-and-pillar method, with an extraction of 60 per cent. The deepest workings, at a vertical depth of 1,850 feet below sea-level, have a rock cover of about 1,500 feet. No mining is done in areas where the rock cover is less than 200 feet. To date mining has explored six square miles of a potential area that may exceed 50 square miles."

Jan 1, 1949

By J. Dilbeck, J. K. Ratliff, T. Petrov, Z. Brown

"In efforts to improve dust control during deep cut continuous mining a supplemental atomizing spray system, mounted on 14CM15 continuous miner, has been designed and successfully implemented in a U.S. coal mine. The mine is 2.1 m (7-ft) high and uses a blowing curtain face ventilation system with 1.1 m (3.5-ft) curtain offset from the rib. The face ventilation design parameters were set to 9.4 m3/s (20,000-cfm); 4.2 m3/s (9,000-cfm) line curtain flow rate, and 3.8 m3/s (8,000-cfm) scrubber capacity. The performed in-mine measurements, before and after the implementation of the atomizing spray system, showed a significant decrease in the respirable dust levels at the operator place as well as at the return. The paper describes the supplemental water spray system design and performance supported by three-dimensional computational fluid dynamics (CFD) simulations and in-mine test data.INTRODUCTIONThe work on this project have started in 2015 with a study of the conventionally applied face ventilation layouts. The specific behaviour of the face ventilation system have been analyzed trough in-mine measurements and computer modeling of typical cut scenarios. An computer modeling methodology have been developed for estimation the respirable dust concentration (RDC) using tracer gas to RDC contour mapping, calibrated by a single point value, provided by in-mine measurement. Utilizing the results of this study the engineering staff of the mine designed and implemented a supplemental atomizing spray system to improve the dust control during the deep cut continuous mining. Today the atomized spray system is successfully applied demonstrating steady performance and a significant decrease in respirable dust concentration on the working places of the continuous miner (CM) and coal transporters (CT) operators as well as at the return air stream. Information about the applied type of spray nozzles provided by other researchers (Cheng, 1973; Dick et al., 1996; Organiscak & Page, 1998; Pollock & Organiscak, 2007) and spray system manufacturers (Spraying System Co, 2011–2018; Steinen Mfg., 2016) have been used in this project. CFD code and simulation approach validated in a study conducted in 2000-2014 have been applied (Turner et al., 2002; Wala et al., 2004, 2007; Petrov, 2014)."

Jan 1, 2019

By K. C. Sole, G. Robinson, M. S. Moats, W. G. Davenport, S. Sandoval

Global practice in hydrometallurgical production of copper cathode by electrowinning is reviewed, based on individual plant operating data for 2018. Data from 29 plants were collected, representing 38% of world cathode copper production. Similar surveys were carried out in 1997, 1999, 2003, 2007, and 2013. This survey includes analysis of historical and current data. Evolving trends in operating conditions and performance, as well as equipment design and process technology choices, are analysed and differences in operating practices with location are assessed. Examples of recent technology and operational choices to increase productivity, improve copper quality, and decrease electrical energy consumption are discussed. Significant project expansions, particularly in Africa, and the consolidation of numerous small Chinese operations are also presented. INTRODUCTION Global trends and operating practices in copper electrowinning (EW) in 2018 are reviewed and evaluated. Similar world and African surveys were carried out in 1997, 1999, 2001, 2002, 2003, 2007, and 2013 (Robinson, Davenport, & Jenkins, 1997; Jenkins, Davenport, Kennedy, & Robinson, 1999; Davenport, Jenkins, Robinson, & Karcas, 2001; Robinson, Garbutt, & Davenport, 2002; Robinson, Davenport, Jenkins, King, & Rasmussen, 2003; Robinson, Davenport, Moats, Karcas, & Demetrio, 2007; Robinson, Sole, Sandoval, Moats, Siegmund, & Davenport, 2013). Contributing operations included sites from the USA and Mexico (9), Chile and Peru (6), Laos (1), Kazakhstan (1), and Africa (9). Despite fewer contributions compared with past experience, this survey nevertheless represents 2018 copper EW cathode production of 1.76 Mt, or about 38% of world production of 4.64 Mt (International Copper Study Group, 2017). This drop in permission to contribute is attributed to the more competitive nature of the industry and unprecedented production pressures; furthermore, several operations in Australia have shut down, while large operations that are currently commissioning or ramping up to full production in Africa and Asia declined to participate. Of the Chinese operations, which represent an increasingly important proportion of global electrowon cathode copper, particularly in Africa, only Tenke Fungurume (Democratic Republic of Congo; DRC) participated in this survey.

Jan 1, 2019