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By Bin Tang, Suping Yao

In the last decade, the copper industry in China has developed rapidly and attracted the world’s attention. The production capacity of refined copper has grown remarkably from 4.578 million tons in 2010 up to 9.029 million tons in 2018, accounting for about 40% of the global refined copper production. And now, China has become the biggest refined copper producer in the world. This paper summarizes the application of modern copper metallurgical technologies such as Outotec flash smelting/converting technology, Cyclone smelting technology, TSL (ISA/Ausmelt) smelting/converting technology, Jinfeng side blown smelting and Baiyin side blown smelting technology, Chifeng side blown smelting and continuous top blown converting technology, SKS bottom blowing technology, Dongying two-step smelting technology, copper electrorefining with high current density, etc. in China’s copper industry, analyzes and compares the characteristics of those technologies and presents the great efforts of China’s copper smelters in adapting to the increasingly strict emission standards and improving economic benefits of copper smelters. INTRODUCTION China has been the biggest refined copper producer in the world for many years. China produced million tons of refined copper in 2018, accounting for 40% of the copper smelting production in the world, and of which, roughly, 70% of the copper concentrate was imported, mainly from Chile, Peru and Australia. ICSG (International Copper Study Group, 2017) shows clearly the position of top 20 countries of copper production and copper mine production (Figures 1 and 2). Blast Furnaces, Reverb Furnaces and Electric Furnaces dominated China Copper Smelting for quite long time till 1980s. The first modern copper smelting technology (flash copper smelting) was introduced into China in 1980s, then followed by Noranda, Ausmelt and ISA. Since then, China copper smelting technology stepped into modern time. Since 2000, old processes (Blast Furnace, Reverb Furnaces and Electric Furnaces) were phased out and replaced by modern smelting technologies. China Copper Production has been increasing dramatically (Figure 3).

Jan 1, 2019

By P. G. Semple

"In January 1985, Equity Silver Mines Limited began operation of a cyanidation circuit to scavenge precious metals from the flotation tailings. At present, this process is treating 270,000 tonnes of tailings per month and is recovering in excess of 0.20 grams of gold per tonne. To obtain these results Equity is operating a carbon-in-leach circuit that utilizes pressure stripping, zinc precipitation acid washing and thermal reactivation. A cyanide destruction circuit is also required to minimize the deleterious effects on reclaim water in the flotation stage. This paper describes the existing scavenger plant, and details the start-up problems encountered and the modifications made to correct these problems.INTRODUCTIONEquity Silver Mines Limited , a 68% owned subsidiary of Placer Development Limited , is located 38 km southeast of Houston in north central British Columbia. The geographic location of Equity Silver Mines is shown in figure #1. In September 1980, production first began with the ore being supplied from the Southern Tail open pit. In March 1984, the Southern Tail deposit had reached its economic pit depth, and since then ore has been supplied by the Main Zone pit the gold mineralization in the Main Zone is less refractory than the Southern Tail and cyanidation of the flotation tailing appeared to be a viable alternative.An extensive test program was undertaken and the results confirmed that considerable gold and silver values were amenable to cyanide leaching. A feasibility study showed that these values could be economically recovered and the detailed engineering work began."

Jan 1, 1987

By A. H. Mumin, A. Prikhodko

"This paper provides an understanding of interpreting and evaluating airborne time domain electromagnetic (TEM) surveys as applied to massive sulfide exploration. Variations in the conductive morphologies of massive sulfide ore systems are discussed, followed by forward modelling exercises examining the derived TEM response to these morphologies and discussion of the subtleties of data interpretation. Deposit morphology in the orientation at formation and the variations occurring due to later deformation are considered. Images of corresponding resistivity–depth models are provided. The combined modelling results provide a low-cost method for initial interpretation and screening of TEM anomalies. RÉSUMÉ Cet article nous permet de mieux comprendre l’interprétation et l’évaluation des levés élec-tromagnétiques aéroportés en domaine temporel (TDEM, de l’anglais time-domain electromagnetic) appliqués à l’exploration du sulfure massif. Y sont débattues les variations au niveau des morphologies conductrices des systèmes de minéralisation du sulfure massif, suivies d’exercices de modélisation prospective qui examinent la réponse dérivée des TDEM à ces morphologies et d’une discussion sur les subtilités de l’interprétation des données. L’étude envisage la morphologie de l’orientation originelle non déformée des gisements ainsi que les variations résultant d’une déformation ultérieure. Des images des modèles correspondants de résistivité-profondeur sont fournies. Les résultats combinés relatifs à la modélisation proposent une méthode peu onéreuse d’interprétation et de contrôle initiaux des anomalies dans les TDEM.INTRODUCTION Electromagnetic geophysical surveys are an indispensable foundation of many mineral exploration programs and can account for as much as half of the predrilling exploration costs. Quantitative mass interpretation of the survey results remains difficult due to the infinite variation of deposit morphologies, their complex physical properties, and the presence of barren conductive materials that can mimic or mask the response of targeted ore. Many modern geophysical investigations that focus on time domain electromagnetic (TEM) data interpretations are devoted to problems with inversion and modelling and their algorithms. Although a few of these investigations have resulted in commercial software products, these require highly qualified and experienced users and usually include geometric assumptions. Furthermore, without the input of known physical properties and geometric constraints, the inversion results are highly ambiguous. A number of case studies document the geophysical responses to known targets in well-defined and diverse geo-electrical environments, providing a high degree of correlation between field obser-vation and the results of the modelling used in this style of investigation (Hone, 1980; Schneider & Emerson, 1980; Tyne, Idnurm, & Malone, 1981; Bishop & Lewis, 1992; Hopgood & Hungerford, 1994; Meju, 2002; Yang & Oldenburg, 2016). The uniqueness of the target/environment parameters and their specific features limits the use logy is poorly understood. The responses are therefore that are devoid of complicating environmental factors (e.g., highly conductive overburden and hostrocks or nonuniform target conductivity) as a first approach to the interpretation process of such case studies as the main reference for interpreting TEM survey responses in areas where the underlying geomodelled from generalized and typical geological models"

Jan 1, 2018

"WELCOME/BIENVENUE TO THE COM 2014 IN BEAUTIFUL VANCOUVER!On behalf of the organizing committee, I would like to extend my thanks to you for participating in this year’s Conference of Metallurgists. Recent times have been extremely difficult for the resource sector, but it is crucial for our industry to maintain personal connections through good and bad times. These interactions include technical exchanges, and this is at the heart of MetSoc’s service to its members. The theme of this 53rd Conference of Metallurgists is Prosperity Through Process Advancements. There are thirteen symposia at this year’s conference mainly focused on processing from extractive fields, to materials and the environment. Supporting these topics are the plenary, poster session, and trade show plus opportunities for socializing at functions like the opening reception and the awards banquet.Many people have contributed to this conference, from the authors and presenters to the organizers and the generous sponsors. They are all gratefully acknowledged for their quality work over the last two years. A particular thank you to our student volunteers whom we hope will take advantage of their time at COM to network and to learn about this exciting industry.Again, thank you for being a part of this exciting conference of metallurgists. I hope it will be a memorable experience and that you are able to take advantage of all the conference and Vancouver have to offer."

Jan 1, 2014

By M. Courchesne, C. Barbery, D. Hodouin, C. Carrier

"The carbon-in-pulp process for recovery of gold dissolved in dilute cyanide solutions, in the presence of solids, has now replaced the convedntional processes of pregnant liquid/barren solids separation followed by Merrill-Crowe precipitation. Most plants built over the past ten years incorporate a CIP section. The process is described as cheaper in capital and operating costs, and few major start-up or operational difficulties are reported. For the purpose of the present paper, the CIP process will be assumed to consist of the following sequence of operations (Figure 1):- the slurry stream coming out of the cyanidation circuit is first screened to remove any tramp oversize material. Gold dissolution is assumed to be complete before entering the CIP circuit.- the slurry is sent into a series of agitated tanks in which it is mixed with activated carbon. The carbon particles size is much coarser than the top size of the ground ore. The tanks are fitted with screens that allows the slurry to overflow continuously into the next tank, while retaining the carbon in the tank. Slurry dilution is adjusted to prevent carbon from settling in the tanks. Agitation intensity is kept low in order to minimize carbon abrasion.- carbon is transfered from tank to tank in a discontinuous manner. According to a specific schedule, the carbon from tank one is removed, then carbon from tank two is sent to tank one, and so on, till the last tank, which is filled with regenerated carbon corning from the elutionregeneration section. The amount of carbon removed, the transfer from tank to tank, the sequence of transfer, the carbon inventory in the various tanks are parameters which are, up to a point, at th2 discretion of the operators, as long as they remove, batch wise, an amount of loaded carbon containing a similar quantity of gold to the one that has entered the circuit since the last transfer."

Jan 1, 1987

By Manuel Sanchez, Marcial Medina, Matt Hurley, Hugo Granados, Pramod Kumar, Raj Rajamani, Jose A. Delgadillo

"Large-diameter ball mills have traditionally used steel liners—steel being a highly durable material that can be shaped into any desired geometry, among which the double-wave has been the preferred design. Such a design produces a purely cascading charge motion, which is ideal for the shearing action needed to produce a finer product. Today, however, rubber liners, which have been in existence for over forty years, are now preferred over traditional steel, largely because they weigh less and are easier to maintain. In this paper, we show the operating data from the Hudbay Minerals’ Constancia Mine, wherein the liners on a 26-by-40-foot mill were changed from conventional steel liners to PolyStl™ liners. It is then shown that this change reduced the amount of energy consumed whilst being able to maintain previous grind and throughput levels. The design is verified via discrete element simulations.IntroductionThe Constancia Mine (“Our Business: Peru,” 2016) is located in the southeastern Andes of Peru, at an elevation of approximately 4,200 m. It can be accessed via the CU-126 road, about 95 km from the town of Espinar in Espinar Province. The mine also contains both the Constancia and Pampacancha deposits in the Province of Chumbivilcas. Hudbay Minerals, Inc. acquired the mine in 2011, through the purchase of Norsemont Mining, Inc. and currently retains sole ownership of the property. Production of the Constancia Mine began in 2014, with commercial production levels being achieved in April 2015.The Constancia and Pampacancha deposits primarily include hypogene, supergene, and skarn ores. The Mine’s main products, however, are copper concentrate, with silver contents, and molybdenum concentrate. These mineral reserves are expected to last approximately 22 years. Constancia’s open-pit mine supplies a processing plant that is designed for 81,900 metric tons per day of throughput. Average annual copper production is estimated to be 82,000 mT (contained metal in concentrate). Actual plant production can be found in Table 1."

Jan 1, 2017

By G. Lipsett, S. Dessureault

Information technology (IT) initiatives in the past have tended to be sold on their ability to maximize resource output and return on capital by allowing assets to be used more effectively and efficiently. Many IT projects fail, not delivering return on their investment. This is known in the IT industry as the “productivity paradox,” where increasing investments in IT do not result in comparable increases in productivity. Experiences and studies of most business sectors reveal that this paradox is rooted in the false assumption that more IT spending automatically results in financial benefit, whereas the benefits are in how effectively IT is used. Most business sectors have accepted that re-engineering of processes is required to gain the full benefits promised of IT. A mining operation has organizational processes similar to most business sectors, but unique operational processes. The lessons of changing business practice in more common business processes, such as inventory control and customer-supplier relationships, can be adequately transposed into a mine setting. The unique operational processes in mines, in turn, require unique redesign efforts. Several enabling information technology opportunities have recently become available, such as more integrated mine production management systems and tactical manager training simulators. This paper reviews some of the latest IT products and outlines the processes and kinds of change that will be required in order to benefit from these new investment options.

Jan 1, 2009

By Norman A. Parlee

Introduction The principal primary iron and steel producing capacity of the Dominion Steel and Coal Corporation is at the Dominion Iron and Steel, Limited, plant at Sydney, Cape Breton Island, Nova Scotia. The main raw materials are Cape Breton coal, Wabana (Newfoundland) iron ore, and Port-au-Port (Newfoundland) limestone. This plant, which was established at the turn of the century has gradually expanded its production facilities so that today its ingot producing capacity is over 720,000 tons annually. Principal operating units of the plant at present are three batteries of 173 Koppers by-product coke ovens with conventional by-product recovery equipment, three blast furnaces .of 15 ft. 6 in., 18 ft. 3 in., and 19 ft. 3 in. hearth diameter (inside the brick), one 700-ton hot metal mixer, ten open hearth furnaces (two of 175-ton capacity, three 12 5-ton, five 60-ton), one 10-ton electric furnace, a 40-inch blooming mill, a billet mill, a rail mill, a tie plate mill, rod and bar mills, and a wire and nail mill. Extensive machine shops and an iron and brass foundry are also available for plant maintenance and repairs. This paper will describe developments during the past five years and those now in process. It will also briefly discuss research being done and indicate the direction of future development.

Jan 1, 1951

By L. C. Bird, N. T. L. Landgren, M. W. Mikhail

"Through funds made available in 1972 by the Nova Scotia Department of Mines and Energy (DME) and the federal Department of Regional Economic Expansion, a program was initiated to recover saleable coal from mine waste dumps adjacent to the existing Acadia wash plant in Stellarton, Nova Scotia.Following evaluation of these dumps in 1972, the Acadia wash plant was modified to treat high-ash material. The first production was recorded in late 1974. By the end of 1979, a total of 738,202 t of dump material had been processed, yielding a total of 205,212 t of thermal-quality coal.The successful Stellarton operation led to considering the possibility of recovering thermal coal from other dumps. Evaluation of the Westville dumps indicated total recoverable reserves of 1,346,617 t averaging 53.8OJo ash.Parameters for plant design were defined from the washability characteristics of the dump material and the results of a bulk test. Two options were proposed; one was to use the existing plant with some modifications, the other was to build a modular mobile plant that could be used at future dump sites in the province after Westville. At the 25% ash level, the potential recovery of coal from the dump was estimated at 41% yield (by weight) or 549,679 t."

Jan 1, 1981

By Dominic Fragomeni

"The mineral processing industry has had a long history of innovation that is recognized but not often celebrated. These include significant advances in mineral measurement, testing, comminution, mineral separation and process control technologies that have transformed mineral assemblages into ore.This presentation presents some of the major mineral processing innovations and the impact they have had on our industry. As we look to the future, it is critical that we innovate and change. We will explore some examples of the next developments and how they can be catalyzed in the face of risk management, lower metal price cycles, resource constraints, inertia and the challenge of short term value delivery."

Jan 1, 2017

By Kevin M. Ansdell, Irvine R. Annesley, Christine L. Mckechnie

The U-Th-REE mineralization at Fraser Lakes Zone B is hosted by granitic pegmatites and leucogranites, which lie along the deformed contact between Paleoproterozoic metasedimentary gneiss of the Wollaston Group and Archean orthogneiss, approximately 25 km from the southeastern edge of the Athabasca Basin. The pegmatites/leucogranites are subcordant to concordant with the regional foliation and are concentrated within a northeast-plunging antiformal fold nose, the study area, which lies west of Fraser Lakes. The mineralized pegmatites/leucogranites in the western part of the study area (Group A) are typically enriched in U (± Th) with Th/U ~1, and contain uraninite, thorite, zircon, and allanite. Those intruding the central part of the study area (Group B) are generally enriched in Th and LREE, with Th/U >2, and contain monazite, thorite (commonly U-enriched), and zircon. The pegmatites and leucogranites in Group A tend to be slightly enriched in SiO2 and depleted in TiO2 relative to those in Group B and are interpreted to represent more evolved crustal melts. Both groups are peraluminous and show varied chemistry. Partial melting (~850ºC and 9 kbar) of a metasedimentary rock-dominated source, entrainment of accessory minerals as xenocrysts, and assimilation-fractional crystallization processes combined to enrich the granitic pegmatites/leucogranites in U, Th, and REE elements. Transfer of melt from the source region to the crystallization sites was assisted by deformation within and along major structural zones, such as the folded Archean-Paleoproterozoic discontinuity. The character of mineralization and structural control in the study area is reminiscent of the alaskite-hosted deposits at Rössing, Namibia.

Jan 1, 2013

By John A. Herbst, Alexander Potapov, Xiangjun Qiu

"High Fidelity Simulation is a name applied to the use of first principles modeling tools including Discrete Element Modeling (DEM), Computational Fluid Dynamics (CFD) and Discrete Grain Breakage (DGB) to mathematically describe and study processing systems. Over the past few years, significant advances have been made in High Fidelity Simulation applications, particularly as many mineral processors have been drawn to the study and use of DEM of grinding mills for optimization purposes. This presentation provides an introduction to High Fidelity Simulation, with an emphasis on DEM. It will include insights into current applications of these tools including the optimal design (wear and throughput) of mill lining systems and media selection, the analysis and design (flow and efficiency) of the back-end of grate discharge mills. Advantages of full mill simulations versus individual sub-process simulations will be demonstrated for a SAG mill with different discharge system designs.INTRODUCTIONHigh Fidelity Simulation is providing mineral processors with the opportunity to analyze the behavior of mineral processing equipment from a fundamental or microscale point of view. In the past complex phenomena such as tumbling mill grinding had to be analyzed using black box tools such as residence time distributions for transport and classification functions for passage of particles through grates; while breakage had to be analyzed using PBM models who derived their form from theory but required direct measurement of kinetics. Today with the help of DEM, CFD and DGB these can be analyzed at a very fundamental level.The key element of DEM simulation is the application of Newton’s laws of motion to individual objects or discrete elements. Using this simulation method one can describe the position, velocity (both translational and rotational) of all objects and the transfer of momentum to other objects (Mishra and Rajamani, 1992; Cleary, 1998; Nordell et al, 2001)."

Jan 1, 2003

By Ralph D. Parker

THE subject matter of this paper will be primarily restricted to the metallic mineral industry, which last year was responsible for almost 60 per •Cent of the total value of Canada's mineral production. It has been written that, in the broad sweep of eternal time, sixty years is as transient as a flicker of lightning in a summer night's sky. In the history of mankind and human endeavour, however, six decades can encompass momentous events and far-reaching •circumstances, all of which affect the lives of men and change the destiny of nations. This observation is con-firmed very positively by a study of our Canadian mining history, from either the broad viewpoint of human progress or the more specialized viewpoint of national economy. The past sixty years have witnessed vast changes in the economic importance of mining in this country's affairs, and also in the technology of the industry. Mining has emerged from the days of rule-of-thumb practice and is now taking on the stature of a highly diversified science.

Jan 1, 1962

By D. R. Griffiths

"Oxidation of pyrrhotite prcxiuces sulphuric acid which in turn leaches out heavy metals, resulting in acidic contaminated seepages. The establishment of a marsh on top of the pyrrhotite would result in an anaerobic sediment, which should prevent further oxidation of the pyrrhotite. Initial data indicates that concentrations of sulphates and heavy metals in the seepage water are greatly reduced. Further hydrogeological studies are required however, to determine if metal and acidic loadings to the environment have increased.L'oxidation du sulfure de fer produit de l'acide sulfurique qui a son tour attaque les métaux ayant pour resultat une contamination d'acide et de métal des eaux d'infiltration. L'etablissement d'une couverture faite de boue et de vase au-dessus du depot du sulfure de fer réduit les effets de l'oxidation.Les données initiales indiquent que les concentrations de souffre et de métaux dans les eaux d'infiltration sent grandernent réduites.Des études plus poussées sent nécessaires pour déterminer si les quantités de souffre et de métaux dans les eaux d'infiltration ont augmentées.INTRODUCITONPyrrhotite tailings are readily oxidized through a combination of precipitation and atmospheric oxygen causing acidification of the unsaturated zone above the water table. This reaction is usually catalyzed by the bacteria, Thiobacillus ferooxidans. As the pH decreases, heavy metals become more soluble resulting in contaminated seepages to ground and surface waters.By creating a marshland on top of the pyrrhotite, an anaerobic intermediate layer should form between the organic covering and the tailings, preventing the oxidation process from progressing.In September 1986, Falconbridge Limited implemented a tailing reclamation project that involved creating a marshland on top of pyrrhotite tailings. The following paper will discuss and illustrate the preliminary results obtained during the sampling period of May to September 1987."

Jan 1, 1988

By Y. Bai, J. J. Liu, D. Q. Li, S. Z. Liu, X. T. Wang

"This paper presents the results of an industrial test using 8 t/d of Baotou concentrate (50% REO) of a clean metallurgical process, which includes: 1. Roasting with H2SO4 at low temperature (220~260 0C) in a batch roasting furnace followed by water leaching to obtain a leach liquor as feed with a yield of >95% RE and Th, recovering F as fluoride, producing a leach residue amounting to 1/3 of an equivalent high temperature residue and containing <0.03% Th and radioactivity < 3×104 Bq/kg compared to the normal high temperature residue containing 0.2-0.3% Th and 1×105 Bq/kg. 2. Separating Th with N1923 and extracting RE by P507 has been completed in mixer-settlers. Test results indicate that the ThO2 product has a purity of > 95% with a yield of 99%, and the RE has a yield of >95%, in which ThO2/REO <5×10-6, and that P507 loaded RE connect straight with separating RE using P507-HCl system. 3. Treatment and multipurpose use of "three wastes" (water, gas and solids) are discussed in some detail."

Jan 1, 2014

By Tim Edwards, Richard Triglavcanin, Ian Arbuthnot, Darren Colwell, Brad Garraway, Ken Roberts

"In the mineral processing industries, there is an increasing need to design thickeners which are able to produce high density underflows usually referred to as “paste”.The behaviour of a flocculated suspension in compression needs to be well understood in order to arrive at a reliable thickener tank configuration (i.e. diameter, cone angle and depth) for a required paste result.As a suspension approaches paste consistency, it’s fluid characteristics change markedly. It develops a high yield stress, and may have an increased tendency to form agglomerates, which lead to a phenomenon known as “rotating beds”, “donuts”, or “islands”. These characteristics present challenges to the designer of the rake mechanism.The subject paper addresses the requirements for designing a paste thickener, covering the following topics:o Testwork for thickener sizingo Design of rake mechanismso Suspension rheology and effect on designo Case studiesTESTWORK AND SIZING FOR PASTE THICKENERSThickening slurries to the maximum possible density (paste) is becoming increasingly common. Applications such as Autoclave feed thickeners, paste backfill and some counter current washing (CCD) circuits are all examples of potential paste thickening applications. The principle of paste thickeners is that the compression zone is much deeper than on either high rate (HRT) or high compression (HCT) units; generally 3 metres or more. As the compression zone gets deeper, theunderflow density for a given flux rate (tph/m2) increases, as a result of two factors:1. Longer bed settling time. Settling flocs move relative to one another and release interstitial fluid when they are in compression. Increasing bed residence time achieves higher density underflow as more fluid is removed.2. The nett weight of the bed creates a compressive force on the settling flocs. This force increases with depth, so that the flocs at the bottom of the bed experience the highest compressive force. This represents the driving force to expel interstitial fluid and hence increase bed density."

Jan 1, 2005

By Jean M. Richardson, Steven R. Williams

"Geometallurgical mapping is a new team-based approach that documents variability within an orebody and quantifies the impact of geology (host rocks, alteration and structure) and mineralogy on grinding, metallurgical response and metal recovery processes. The quantitative, spatially constrained database that results can be readily integrated into 3-D block models and mine planning activities. Thus it is an important tool to reduce the technical risk associated with new mine developments or expansions.Normally undertaken during pre-feasibility or feasibility planning stages, the first step of geometallurgical mapping is to review the geology, mineralogy and other critical parameters and construct a geometallurgical matrix. This matrix provides an objective base to then guide sampling and/or compositing activity for physical property and metallurgical testing. Depending on the project, an array of testing techniques can be used to characterize the ore and feed data into the geometallurgical model.While the range and number of tests needed is project-dependant, the geometallurgical mapping approach allows the development of empirical models or interdependent relationships, grounded by spatially-constrained real data. Extensive data sets collected using less expensive testing methods can be meaningfully correlated with results from complex specialty tests to yield realistic metallurgical recovery data.With geometallurgical mapping completed, the resulting database can be integrated into an overall 3-D block mine model. This means that metallurgical response can be used to realistically forecast the recoveries of specific blocks, perhaps sampled only by drilling. Mine planning can then incorporate the forecasted metallurgical response and generate future project cash-flows; opening the door to economic optimization of the mine exploitation."

Jan 1, 2004

By R. Al-Hent, M. Aissa, J. Asfahani

"This paper focuses on determining the favorable geological and hydrogeological conditions for forming uranium occurrences in the Froqlos-Jabal Abou Rabah region, Palmyrides, Syria. Eighty rock samples from this area were analyzed by spectrometric gamma-ray technique to determine the radioactive concentrations of eU and eTh, and of %K. Uranium concentrations in shallow and deep groundwaters were also determined. High uranium concentrations were registered owing to the presence of phosphatic outcrops in the study region. The uranium migration trends and its remobilization were analyzed through the analysis of the behavior of eU, eTh, and their ratio. A positive relationship between eU and eU/eTh, and a negative relationship between eTh and eU/eTh in geological formations of different ages supports the secondary remobilization of uranium. The role of groundwater movement in transportation and redeposition of uranium mineralization is discussed: deep waters are less oxidizing than near-surface waters, and do not appear to have significantly remobilized uranium. This indicates that the source of secondary uranium mineralization is surficial or near surficial, and is mainly related to the leaching of outcropping phosphatic layers.Integration of the results with established radioactive and geological sections reveals four radioactive anomalous zones: north Froqlos, Kherbet Hannora, northwestern flanks of Jabal Abou Rabah (Kherbet Al-Hajar), and the northwestern limit of the Ghuntor depression. The high uranium concentration in north Froqlos is because of its original presence in the phosphate beds and extensive fracturing, which allows groundwaters to penetrate and remobilize the uranium. High uranium concentrations in the other three locations are caused by the presence of evaporites and capillary action, which draws solutions upwards and causes redeposition as surface crusts (gypcrete)."

Jan 1, 2009

By James R. Wickens, David La Rosa, Robert E. McIvor, Adrian Dance

"The comminution circuit at Barrick Cortez Gold Mine uses an open circuit primary jaw crusher followed by a standard SABC grinding circuit. The grinding circuit incorporates a 26’Ø x 11’ SAG mill, an Omnicone 1560 pebble crusher and a 16’Ø x 28½’ ball mill. Both mills are driven by 4500 HP motors.In 2007, several comminution circuit studies were performed to assess circuit performance and map a course for improvement. This paper discusses the results of those studies including an analysis of mine-to-mill opportunities, grinding work index efficiency, and ball mill functional performance. Subsequently, improvements to the circuit were made to enhance operating efficiency. Specifically, improvements to the pebble crusher liner configuration, advanced process control system (expert system) and ball mill classification and ball charge are discussed. In addition, other current and future improvement opportunities are discussed.INTRODUCTIONThe Barrick Cortez property is expanding to include the new Cortez Hills open pit and underground mines. Ore from these new mines will be processed in the existing Pipeline mill facility. In conjunction with ore characterization work, performance of the comminution circuit needed to be quantified. Thus, in 2007, the comminution circuit was surveyed and opportunities for improvement identified.Figure 1 below shows the Pipeline mill flowsheet. It is a standard SABC grinding circuit using an open circuit primary jaw crusher followed by a 26’Ø x 11’ (7.92m Ø x 3.35m) SAG mill, in closed circuit with a Omnicone 1,560 pebble crusher, and a 16’Ø x 28½’ (4.88m Ø x 8.69m) ball mill. Both mills are driven by 4,500 HP (3,357 kW) motors. The SAG discharge screen aperture is 5/16” (8 mm) x 1-1/16” (27 mm) slots. Ball mill circuit classification is done with Krebs D20B cyclones."

Jan 1, 2009

By Zbigniew J. Hladysz

A Deep Underground Science and Engineering Laboratory (DUSEL) is being planned at the site of the former Homestake Gold Mine in Lead, South Dakota, under the sponsorship of the US National Science Foundation (NSF) in cooperation with the US Department of Energy (DOE). This national facility will host a variety of multidisciplinary science and engineering experiments including physics experiments that require shielding from cosmogenic radiation. Geotechnical mapping was performed in 2010 in large excavations of the Davis Campus at the 4850 Level of the former Homestake Mine. LIDAR mapping included laser scanning using a red light laser scanner and 288 Mpixels 360° still camera. The resulting vector map with the photographs digitally draped over the model, was used to create an accurate, virtual model of the excavations. For model verification, the laser scanning was accompanied by surveying and manual mapping of the geology and rock structure. The immediate use of the model was to perform structural analysis and interpretation of geology needed for the design of the DUSEL?s super large excavations. The second round of scanning, after the application of shotcrete to the excavations walls, will be used as a technical blueprint to assess the effectiveness of shotcrete application.

May 1, 2011