Search Documents

By Alex Doll, Derek Barratt

"There is a number of comminution tests commonly used in the mining industry. Many of the tests are used for a particular grinding model or mill sizing program and are incompatible with other tests of different models. This paper provides an overview of the commonly used grinding and crushing tests, which models (or practitioners) use a particular combination of tests and draws some relationships between the incompatible tests based on the DJB Consultants Inc. database of projects.Case studies will demonstrate similarities and differences between major mining districts with some comments about homogeneous and heterogeneous behaviour within the grindability results.INTRODUCTIONThere are a number of bench-scale grindability tests in use for sizing and predicting throughput for grinding circuits. Part of the reason for this variety is there are a number of different grinding models in use in the Industry, and those models operate using incompatible test results as input (Doll and Barratt, 2008).By using the database of testwork in the DJB Consultants, Inc. (DJB) Millpower 2000 database (see Table 1), some of the more commonly used tests are compared and relationships will be drawn."

Jan 1, 2011

By Michel Massé

Eleonore Project- Agenda ? Purpose and Technical Overview ? SmartEXEC Control Capabilities ? SmartEXEC System Archetecture ? SmartEXEC System Advantage Eleonore Project- Purpose and Technical Overview ? Control air quality while maintaining target production levels at minimum energy operating cost ? Improve safety, work place conditions and operation flexibility ? Reduce energy consumption and green house gases footprint

Aug 1, 2013

By Lawrence Winter

why are these deposits significant? (i) economically and (ii) in a VMS/geological context. ?Significance of the tectonic setting. ?New understanding of the regional geology: volcanic stratigraphy, first geochronologic data. ?Deposit geology: paleomorphologyof the seafloor setting. ?Lessons and conclusions ?Regional Potential

May 1, 2006

By D. J. Kemp

The 20th century saw changes in the mining and metallurgical industry not only technically but also in social and environmental expectations. As projects continue to become larger their visibility raises concerns among many groups. For mining companies, transparency, openness, and early engagement of all parties are fundamental to assure success. An equally important task is to anticipate the standards that will be required to meet society’s expectations in the 21st century.

Jan 1, 2005

By Joe Zhou

"Mineralogical characterization and metallurgical extraction of silver is challenging due to its complex mineralogy and chemistry. Over 200 Ag-bearing minerals have been identified and a silver-rich ore body would typically contain 5 to 10 different silver minerals. Silver can occur not only as discrete microscopic (visible) silver minerals but also as submicroscopic (invisible) silver in other minerals. During processing, silver may form passivation compounds such as silver hydroxide, silver sulphide, jarosite-like silver sulphate, silver halide or silver cyanide precipitate, all of which may negatively impact on silver extraction. Knowing the deportment of silver in the ore and its metallurgical products is important in flowsheet design and plant optimization. This paper begins with the classification of silver ores and minerals and a review of processing techniques, and focuses on the major mineralogical factors to explain why and how these factors affect silver extraction. Case studies are provided to demonstrate the application of silver process mineralogy in flowsheet design and plant optimization.INTRODUCTIONSilver was known to and utilized by mankind since ancient time. Actually, it was one of the earliest metals discovered and utilized by mankind after gold and copper.Silver is the whitest metallic element. It is rare, strong, corrosion resistant, and unaffected by moisture, vegetable acids, or alkalis. Silver is also resonant, moldable, malleable, and possesses the highest thermal and electric conductivity of any substance. The chemical symbol for silver is Ag, from the Latin argentum, which means white and shining. Although silver does not react with many chemicals, it does react with sulfur, which is always present in air at trace amounts. The reaction causes silver to tarnish, and consequently it must be polished periodically to retain its luster.Silver possesses many special physical characteristics and qualities that make it useful to a variety of industries. The photography industry is the biggest user of silver compounds. Silver forms the most light-sensitive halide salts, which are essential to developing highquality photographic prints. Silver also has the highest electrical conductivity per unit volume of any metal, including copper, so it is used extensively in electronics."

Jan 1, 2010

By K. G. Thorne, L. J. Cabri, L. R. Fyffe, D. R. Lentz, D. Hoy

"Mineralization at the Main zone of the Clarence Stream gold deposit in southwestern New Brunswick occurs within a parallel series of quartz veins that occupy a NE-trending, steeply north-dipping, brittle-ductile shear zone related to the nearby terrane-bounding Sawyer Brook fault. This deformation zone cuts volcaniclastic sedimentary and volcanic rocks of the Silurian Waweig Formation, and is intruded by mantle-derived East Branch Brook gabbroic dikes and a number of felsic dikes. Intermittent shear-zone reactivation during local magmatic activity induced heterogeneous deformation and alteration of the country rocks and dikes. The terminal phase of shearing is associated with narrow pegmatite-aplite dikes that grade laterally into granophyric granite, and into an auriferous quartz vein. Gold, aurostibite, and gold-antimony intergrowths, predominantly with vein quartz, are associated with a low ƒO2 sulfide mineral assemblage (pyrrhotite, arsenopyrite, and berthierite) that has a sulfur isotopic signature consistent with a magmatic source. Gold saturation and deposition occurred episodically between 300° and 360°C at low activity of sulfur, predominantly in response to pressure reduction during brittle failure combined with the effects of decreasing temperature and sulfidation reactions during fluid-wall-rock interaction. Geochronological studies demonstrate that the timing of the emplacement of the pegmatite-aplite dikes and associated auriferous veins overlap with that of the Early Devonian Magaguadavic granite. Moreover, the composition of the dikes is consistent with their derivation from this granite as late fractionates. The Main zone of the Clarence Stream deposit is therefore interpreted to be intrusion-related, with the Magaguadavic granite being the ultimate source of the gold-bearing fluids. La minéralisation de la zone principale du gisement aurifère de Clarence Stream dans le sud-ouest du Nouveau Brunswick occupe une série de veines de quartz parallèles dans une zone de cisaillement fragile-ductile de direction NE et à pendage abrupt vers le nord apparentée à la faille de Sawyer Brook avoisinante qui délimite deux terranes. Cette zone de déformation recoupe les roches volcaniclastiques et volcaniques de la Formation de Waweig d’âge Silurien et est recoupée par les dykes de gabbro d’East Branch Brook, d’origine mantellique, ainsi que par divers dykes felsiques. La réactivation intermittente de la zone de cisaillement durant l’activité magmatique locale a entraîné la déformation et l’altération hétérogènes des dykes et de l’encaissant. La phase finale du cisaillement est associée à de minces dykes d’aplite-pegmatite qui passent latéralement à des granites granophyriques, puis à des veines de quartz aurifères. L’or, l’aurostibite et les intercroissances d’or et d’antimoine principalement associées aux veines de quartz sont associés à un assemblage minéral de sulfures à faible ƒO2 (pyrrhotite, arsénopyrite et berthierite) présentant une signature isotopique du souffre compatible avec une source magmatique. La saturation en or et la précipitation a eu lieu épisodiquement entre 300° et 350°C dans des conditions de faible activité de souffre, principalement en réponse à la baisse de pression durant la rupture fragile ainsi qu’aux effets de la baisse de température et aux réactions de sulfuration durant l’interaction entre le fluide et l’encaissant. Les études géochronologiques indiquent que l’âge de la mise en place des dykes de pegmatite-aplite et des veines aurifères qui leur sont associées coïncide avec le granite de Magaguadavic, d’âge Dévonien Précoce. De plus, la composition des dykes est compatible avec une origine provenant de ce granite sous la forme de phases fractionnées tardives. Le gisement principale (Main zone) de Clarence Stream est ainsi considéré comme étant associé aux intrusions, le granite de Magaguadavic étant la source ultime des fluides aurifères."

Jan 1, 2008

By Raj K. Rajamani, Sanjeeva Latchireddi, Dave Plummer, Stieger. Julius

"The Cortez SAG mill liner design was recently modified to improve the mill operating energy efficiency. In addition to the expected benefits, the design change unexpectedly played a significant role of verifying the proposed grinding circuit expansion for the Cortez Hills project as well as illustrating current SAG mill bottlenecks. This paper will discuss the evaluation that addressed operator and maintenance observations, historical PLC data, and “crash stop” observations to calculate charge motion, packing between lifters, and slurry transport through grate and pulp lifters. The performance of the new shell and discharge end liner design will also be discussed as well as their role in the possible grinding circuit expansion.INTRODUCTIONCortez Gold Mines commenced operation in 1969 with its Mill #1 rated at a nominal 2,000 tons per day. Mill #1 was a conventional rod mill/ball mill circuit followed by an 8-stage CIP circuit. In the early 1990s the Pipeline deposit was discovered and subsequently Mill #2 was built to process the increased ore volume. Mill #2, commissioned by mid-1997, was a nominal 10,000 tons per day SABC circuit followed by an 8-stage CIL circuit for oxide gold ore. Operating and commissioning details of this plant have been published elsewhere (Powell, 1998). By late 1998, there was not enough ore volume to support both mills so the smaller, higher operating cost Mill #1 was put under its current care-and-maintenance status. A simplified flowsheet of the current mill is shown in Figure 1."

Jan 1, 2007

By John G. Kelly

"In 1982 an extensive study was carried out to determine the best means of size reduction for the ore to be hoisted through the borehole hoisting system at Sherritt Gordon's Fox Mine.The study examined three alternatives:1. a jaw crusher,2. pneumatic rockbreaker(s) at a grizzly, and3. hydraulic rockbreaker(s) at a grizzly.The final decision was a compromise between alternatives 2 and 3. Two rockbreakers, one pneumatic and one hydraulic, were installed over a single grizzly. Some modifications have been made to the system, but over-all it has operated at acceptable levels since its installation in July 1983.As all the ore passes through a jaw crusher before being hoisted to surface, an evaluation of the relative performance and cost-effectiveness of the jaw crusher and the two types of rockbreakers is possible. This paper outlines the initial study, and compares the three breaking systems in operation at Fox Mine.IntroductionThe Fox Mine of Sherritt Gordon Mines Ltd. is located 800 kilometres north of Winnipeg near Lynn Lake in Northern Manitoba. Production at the copper-zinc orebody began in 1970 at a rate of 3,000 tons per day. Over 12.5 million tons will have been hoisted from the underground mine when the ore reserves are depleted in October 1985.The mining method at Fox Mine is sub-level open stoping with delayed backfilling are from the upper level stopes, above the 2000 level, is mucked on the main levels established at 400-ft elevation intervals, and is fed through a central orepass to the crusher located on 2100 level. Production in the lower levels commenced in 1975, and ore from the 2200 and 2400 level stopes was hauled up a 15010 ramp by 26-ton trucks to the 2000 level orepass dump. Projected production rates from the 2600 and 2800 levels using the trucking system were too low, and therefore, in 1983 a borehole hoisting system was commissioned to hoist that ore'!'. One thousand tons per day of ore are skipped through an 8-ft diameter borehole from the 2650 level loading pocket and dumped on the 2000 level. The ore is transferred by LHD to the main orepass for crushing before being conveyed to the main shaft for hoisting to surface (Fig. 1)."

Jan 1, 1986

By Brian A. Ferguson, Raynald O. Vezina, Marielle Gaudet, Raoul R. Boissonneault

"Kiena has been committed to developing a fresh management and employee relations approach since the commencement of production in 1981. The functional organizational structure encourages joint participation and commitment on the part of all employees to common goals in safety and production. The results over the last four years have been extraordinary. Kiena won the John T. Ryan Canada Trophy for 1983 for its safety record and has experienced a steadily increasing productivity through the application of new mining equipment and technology in the hands of a well-trained and motivated team of employees.This paper serves to highlight the fact that productivity, safetyand technical innovation are closely linked to employee participationand involvement which are likely to be the key to theCanadian mining industry's survival in the years ahead.This presentation follows up on an earlier unpublished paper, given at the 84th Annual Meeting of CIM in Quebec City in April, 1982, which discussed the philosophy and the planning which took place before implementation of the management and employee relations system at Kiena. This present paper reviews and expands on material given in the earlier work. IntroductionThe mining industry, which has always been considered as rather conservative in its approach, has experienced with some regularity, cyclical periods related to metal prices. These cycles, previously foreseeable to some extent have become less coherent over recent years during which time the industry has had to face fierce international competition. The issue to productivity is without doubt the major concern of the mining industry in Canada today and it represents the greatest challenge facing us during the present decade. Developments that have been made in mining technology over the precious two decades have failed to completely produce the significant advancements in higher over-all productivity that were expected."

Jan 1, 1987

By K. Schrijver, G. Beaudoin

"Four occurrences of galena-cemented sandstones, exposed in the Lower St. Lawrence - Gaspésie area, are described. They constitute a new, insufficiently explored type of deposit in Quebec.One mineralized body, a minor occurrence, is hosted in Lower Devonian rocks deposited in an estuarine, intertidal river channel during a marine regression; major cements are dolomite and sulphides. Another occurrence, a drilled prospect, is hosted in Upper Silurian rocks deposited unconformably on Cambro Ordovician basement during a marine transgression. With galena and quartz as main cementing minerals, it is similar to some well-known, economic sandstone-lead deposits. A third and fourth, a drilled prospect and a minor occurrence, are hosted in Upper Cambrian rocks deposited on continental slopes. In both, sulphides mainly occupy a secondary porosity. The differences between the third and fourth occurrences are: (1) cementing translucent minerals (carbonates and barite in one; chlorite in the other); (2) chronology of final subsurface dissolution (prior and subsequent to sulphide precipitation, respectively); and (3) important fracture porosity only in the barite-bearing deposit.The diversity of the four occurrences, and the unequal geological knowledge of their respective features, prohibit the formulation of uniform guidelines for further exploration.IntroductionThe attention of the mineral exploration community is drawn to four occurrences of galena-cemented sandstones (Fig. 2A) in the Cambrian of the Taconian Orogen and in the Siluro-Devonian basin of the Lower St. Lawrence and Gaspésie area (Fig. 1). In view of the fact that sandstone-lead deposits (Bjerlykke and Sangster, 1981) are, or have been, mined in several countries (e.g . Laisvall in Sweden: see Rickard et al., 1979; Largentiere in France: see Foglierini et al., 1980), the mere presence of occurrences in Quebec indicates that the mineral potential of some parts of the Appalachians requires further evaluation.Exploration for the deposits considered here is essentially restricted to geological methods and drilJing (e.g . Mainguet Suares and Samama, 1969), since the response to geophysical methods is virtually nil, at least in the initial, surficial stage of an exploration program. As the particular disciplines of geology utilized in exploration depend a great deal on the geological setting of a mineral occurrence, the diversity of the Quebec deposits is of prime importance. Therefore, the four occurrences (Fig. I, Table 1) studied by the authors are herein briefly described with emphasis on their stratigraphic and tectonic setting, and on the evolution of pore space and sequential occlusion of pores and fractures. Prior to further research in and around the occurrences, now in progress (e.g. Beaudoin, 1987; Beaudoin et al., 1987), it is hoped that the following outline will be useful to the explorationist."

Jan 1, 1987

By Ian Holl, Adam Hempstock, Rickardo Welyhorsky, Niel Morrison

"The Victor Diamond Mine is located in the James Bay lowlands, 90 km west of the First Nations village of Attawapiskat. The project was the first of its kind in northern Ontario and was completed approximately 9 months ahead of schedule.The Victor Mine process plant flowsheet was designed to produce a 95 - 98% by weight diamond concentrate. Main processing steps include 3 stages of comminution, dense medium separation and proprietary x-ray technology for final recovery. Reagent consumption for this process is limited to flocculant, for thickening of fine processed kimberlite, and FeSi for the dense medium separation.The commissioning phase of the Victor Project was executed over a period of 6 months and commenced prior to substantial completion of construction. The approach used was to focus on and complete commissioning of the higher risk dense medium separation and recovery systems prior to construction completion of up stream systems.INTRODUCTIONThe development of the Victor Diamond Mine took place over a period of approximately 5 years and had a capital cost of CAD997 million. It was a greenfields project in an undeveloped region of northern Ontario, only accessible by winter road. Figure 1, below, displays the location of the project within Ontario.The main stages of the project included feasibility, environmental permitting, engineering, construction, and commissioning. At the onset of the engineering phase, the mine was scheduled to enter production in October 2008. Through a team effort between AMEC and DeBeers Canada, the schedule was advanced by 6 months towards the goal of project completion in April 2008. Production status was attained in January 2008, approximately 9 months ahead of the original schedule. This paper focuses on the commissioning aspects of the project and includes a less detailed discussion of the engineering stage."

Jan 1, 2010

By Neil H. Brown

Outline ? Cameco - Cigar Lake ? Cigar Lake Mine Development ? MDS #1 ? MDS #1 Improvements ? MDS #2 ? MDS #2 Improvements Pending ? Acknowledgements Mine Development System ? Mining methods tested and developed over the years ? Construction began officially in 2005 ? Water inflow events in 2006 and 2008 ? Successful dewatering and re-entry in 2010 ? Remediation continues ? Production target is mid-2013

Oct 1, 2010

By A. Taylor, M. Blanchette, J. Doucet

"A Z1600 Jameson Cell Test Rig was rented for test work at Vale’s Clarabelle Mill operation. This paper discusses the evolution of renting the unit for test purposes to owning the unit and operating it as a revenue generating process component. The paper focuses on three aspects of the Z1600 project; the initial rental and installation, the test work performed in the cleaning circuit, and the business factors which led to the unit being permanently incorporated into the copper circuit.INTRODUCTION Clarabelle Mill is located in Sudbury Ontario (approximately 350 km north of Toronto) on the southwest rim of the Sudbury basin a meteoric impact crater that is 62 km long and 30 km wide. The result of the meteoric impact was concentrated nickel (Ni), copper (Cu) and platinum group metal (PGM) ore bodies in the outer perimeter of the basin; described in more detail by Hanley (1957). Vale currently has seven operating mines in the Sudbury basin, from which nine distinct ore types are mined. Ores are also received from two QuadraFNX mines. Clarabelle Mill processes all of these ores for the Ontario Operations of Vale. The mill, commissioned in 1971, was originally built as one of four mills operated by then Inco Limited. Between the late 70’s and the early 90’s process changes were made to consolidate the Sudbury Operations milling processes into a single operating mill, Clarabelle Mill. In 1990, the SAG mill was installed resulting in peak mill throughput of 11.9 million short tons per annum (Mstpa), with typical throughputs of ~10 Mstpa. Mill average feed grades were 1.4% Cu and 1.2% Ni. During the resources boom, plans were developed to increase the mill capacity at Clarabelle Mill in stages to a final capacity of 13.5 Mstpa. The project known as the Clarabelle Mill Expansion and Recovery Project (CMERP) included expansion and reconfiguration of the grinding and flotation circuits. The first stage was a planned increase in grinding capacity with the reallocation of existing mills, the existing flotation capacity would be required to treat higher throughput until the new flotation circuit was constructed."

Jan 1, 2012

By C. Kennedy, S. Jensen

Traditionally, mineral processing plants are designed to achieve the highest recovery of valuable material with limited regard for the cost of managing waste products-both solid and water components. As an industry, we are confronting ever more stringent environmental standards and lower grade deposits requiring more intensive processing. The most profitable processing route can, in fact, lead to costly issues downstream. Issues or risks associated with waste management include water treatment and handling and storage of potentially acid generating material. The capital and operating costs of dealing with these issues are significant and should be considered as a consequence of plant design and optimisation. The authors of this paper are involved with a number of projects where process operation changes offer opportunities to mitigate risks associated with water and waste management. Examples of these changes will be discussed along with the estimated benefits to the value of the project and reduction of long-term environmental risks. Process changes include 1) the application of in-plant water treatment as opposed to dealing with the entire tailings management facility and 2) the potential to reduce metal leaching and acid rock drainage through the preferential liberation of carbonate minerals in the grinding process.

Jan 1, 2014

By The Staff

Introduction For many years the necessity of mechanization of all the underground services in the collieries of the Dominion Steel and Coal Corporation in the Sydney, Pictou, and Cumberland coalfields has been foremost in the minds of those concerned with the engineering and operating policies of the Corporation, and a gradual policy of the mechanization of these services has been undertaken over the years, until nearly all the underground services, except the actual loading of the coal at the face, have been mechanized. Early in 1928, experiments in mechanical loading were conducted which finally culminated in the installation of mechanical loading units in our No. 20 colliery in 1938. This attempt at mechanization of the final underground services proved unsuccessful because the workmen were not ready to accept complete mechanization, and the fruition of many years of study was delayed until the year 1947. During the ensuing years, the engineers and operators of the Corporation had studied the possibility of adapting to conditions prevailing in Nova Scotia mines the many types of loading equipment in use in the United States and Europe. The varied physical conditions which exist in the fields operated by the Corporation rendered it extremely difficult to apply the equipment and technique successfully employed in the United States, and more recently in Europe, and special techniques have had to be devised to meet the need of each individual colliery. Prevailing physical conditions in the Nova Scotia fields find no parallel for mechanization with those of any other part of the American continent.

Jan 1, 1949

Block caving is an underground mining method for the profitable extraction of massive, low-grade orebodies. Lately, it has become the mining method of choice, for many mining companies, because of depleted high-grade orebodies, and declining metal market prices. Block cave mining, however, still faces several challenges. Lack of access to the cave remains a major issue in understanding the rockmass response to mining for method optimisation. Improving our understanding of the rockmass response to caving will lead to safer and more productive operations. Combining large datasets from multiple sources with virtual reality scientific visualisation (VRSV) is a viable alternative to understanding complex cave behaviour without access to the cave. This is achieved using immersive environments with the ability to view complex multi-dimensional data (beyond 3D) graphically. VRSV offers a unique platform where it becomes possible to immerse the multi-disciplinary experts, and/or management team, in a virtual mine environment for quick decision making and fast resolution to conflicting conclusions. The underground mining system is complex due to multiple interrelating factors such as geology, excavation geometries, stress and time. Block caving is even more complex than most underground mining methods due to the network of tunnels required, and the use of induced stress, among others. As a consequence of the complexity in the block caving environment, it is vital that the mining system is analysed holistically, as a system, rather than optimizing individual factors one at a time. This paper presents a customised software module developed for use in the Advanced Visualisation Interactive Environment (AVIE) at The University of New South Wales (UNSW), Australia, to enable VRSV investigation into block cave mining systems (BCMS). This approach has the potential to provide a better understanding of the effect of time in in rock engineering, which has proven to be an important factor in hard rock mines (Ma & Daemen, 2006; Malan et al., 1997; Suorineni, 2010) but never validated. This work back analyses the early undercutting phase of a case study block caving operation with the view to understanding time/sequence effects. There is evidence that heterogeneous rockmass time-dependent behaviour governs the seismic response of the rockmass following undercut developments.

Jan 1, 2015

By Joseph N. Bakambu

It is currently recognized by mining society that autonomously guided underground mining vehicles may greatly increase the efficiency of mining production and improve human safety. Recent results in mobile robotics, data fusion and sensor development provide a solid basis for solving the problems related to autonomous underground navigation. Recently developed commercial systems mostly rely on the infrastructure that is expensive and difficult to maintain. Guideless navigation in unstructured and harsh environment of underground mines is still a challenging task. In this paper, we describe an autonomous navigation system for an underground mining vehicle equipped with on-board dead reckoning, inertial and optical sensors. This system does not require any artificial infrastructure and is capable to guide the vehicle along the complex environment of interconnected underground drifts; it also ensures the detection of obstacles on the vehicle path. The user interface for monitoring and control is described and the results of laboratory tests and on-site experiments are presented. Work in progress addresses the system integration for real equipment, and the system upgrade, adding map-building and selflocalization capabilities .

May 1, 2002

By W. A. Ahrens, J. H. McNamara, J. G. Franek

"An economical, pollution-free process has been developed for the hydrometallurgical extraction of copper from sulphide ores. The extracted copper, in the form of cuprous chloride (CuC/), is converted by reduction to copper metal. The metal is melted and fire -refined into wire bars which meet the standards of electrolytic tough pitch (ETP) copper wirebars. IntroductionThe successful development of the Cyprus Copper Process has been an evolutionary series of events covering a time span of some nine years. The original process, based on an electrolytic membrane cell principle , was abandoned in 1975 because of technical, economic and pollution problems. During the past four years, the pilot plant has been reconstructed based on a new flowsheet and operated successfully in several campaigns, some for as long as four months. The pilot-plant hydro section operates at a 225-lblhr copper rate. In October 1977, a feasibility study was completed by Jacobs Engineering, Pasadena, California. The study showed favourable economic and technical feasibility. Jacob's studies in 1978-79 revealed favourable comparative economics with other known pyrohydro processes and favourable economies of scale.The Cyprus Copper Process converts copper concentrates of varying composition into copper metal, which has been proven to be equivalent in every way to electrolytic tough pitch copper, suitable for electrical applications. This is accomplished at capital and operating costs which are estimated to be lower than those associated with any other known currently applicable technology. Also, the total energy requirement is equal to or less than any other known process and the process is essentially pollution free."

Jan 1, 1980

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 Adil Aledresse, Louis Mercier, Laxman Amaratunga

"The development of high capacity adsorbents with uniform porosity denoted, MP-HMS (Mercaptopropyl – Hexagonal Mesoporous Structure) using nanotechnology, and their ability to extract gold from solution, is presented. The preparation of highly effective heavy metal ion adsorbents by the incorporation of thiol moieties into the pore channels of mesoporous silica molecular sieves has been the subject of many nanotechnology research investigations. The unique feature of these nanoporous adsorbents is their ability to adsorb gold ions from ultra-low concentration solutions like mine effluent as well as from leached solutions in gold mills. The preliminary studies from laboratory simulated gold solutions show that the adsorption capacities of these materials are also among the highest reported. MP-HMS has shown the capability to adsorb 370 mg gold per one gram of the nanomaterials from Tetrachloroaurate solution (up to 37% of their weight). Experimental studies indicated that the maximum adsorption of gold (as high as 99.9% recovery). The current studies will be extended to investigate the interaction of ionic gold complexes with nanomaterials. Future development of this work may lead to either to replace the conventional CIP/CIL processes or use nanomaterials in tandem with the former, suggesting plausible use of mesoporous material in pulp, MIP or in leach, MIL, as a novel gold extraction process.INTRODUCTIONGold typically occurs at very low concentrations in ores less than 10 g/t or 0.001% (mass basis). At these concentrations the use of aqueous chemical (hydrometallurgical) extraction processes is the only economically viable method of extracting the gold from the ore. Typical hydrometallurgical gold recovery involves a leaching step followed by the separation of the gold bearing solution from the residues, or adsorption of the gold onto activated carbon adsorbent. After elution from the activated carbon the gold is further concentrated by precipitation or electrodeposition."

Jan 1, 2008