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By Chen Xia, G. Deschenes, Wan-Tai Yen

"Ammonium thiosulphate is a potential replacement for the cyanide in gold leaching. However, the high reagent consumption hinders its practical applications. In order to reduce the thiosulphate consumption, chemical additives were used. The gold leaching tests were conducted on a sulphide copper-bearing gold ore with 0.3M thiosulphate, 0.03M copper sulphate and 3M ammonium hydroxide solution at 44% solids and pH 10.2. Sulphate, sulphite, amino acid and chelating agents were initially used as additives. It was found that chelating agents (EDTA and NTA) could reduce the thiosulphate consumption from 30 kg/t to 17.8 kg/t with some increase of gold extraction. The improvement from other additives was not significant. Other approaches were also attempted to reduce thiosulphate consumption with some success. The thiosulphate consumption could be reduced to about 17 kg/t by reducing copper sulphate concentration fiom 0.03M to 0.0015M; adding 0.04M of EDTA; replacing copper sulphate with 0.001M of nickel sulphate. The increase of pulp density fkom 44% to 60% solids could reduce the thiosulphate consumption to 17 kg/t as well. Limiting the dissolved oxygen content by sparging nitrogen reduced the thiosulphate consumption further to 10 kg/t. It could be concluded that the regulations of copper and oxygen supply in the lixiviant were the keys to reduce the reagent consumption.INTRODUCTIONCyanidation, as the predominant gold leaching method, has been used in mining industry for more than a century. The low reagent requirement and the high performance are the reasons for its great success. However, cyanidation cannot deal with ores containing large amount of copper, nickel, arsenic and zinc minerals. This type of ore may consume more reagents and result in a poor gold extraction. On the other hand, the carbonaceous materials may preg-rob the gold from pregnant solution and make cyanidation a problem leaching method. Further more, the high toxicity of cyanide represents another challenge to modern gold mines. In the beginning of the year 2000, an environmental disaster caused by an accidental spill in Yugoslavia was broadcasted world-widely (Gurevitch 2000). Gold mine operators are facing higher social pressures and increasing costs on environmental protections. The usage of cyanide in mining industry has been banned in some countries and locations such as Czech Republic, Japan, Turkey, California, Colorado, Wisconsin and Montana States. Thus, a non-cyanide lixiviant is required."

Jan 1, 2002

By Donald Leroux, Jean-François Wilhelmy, Ahmed Bouajila

"A young private R & D organization, COREM celebrated its 10th anniversary in 2009. Managed by a consortium of nine mining and metallurgical companies, COREM has the mandate of increasing the competitiveness of its member companies through the development and transfer of mineral processing innovations. Typical technologies developed by COREM include alternative mineral processing techniques, novel operating strategies, innovative sensors and process simulation software. Many of them were developed in partnership with universities and selected research organizations.Because the COREM membership base is broad (from ferrous to base, to precious metal industries), its R & D program must deliver technologies with applications within a wide spectrum of mineral processes. Comminution, physical (gravity and magnetic) separation, flotation, cyanidation, pelletizing and thermal processes are the main topics of the R & D program. A number of new technologies have been developed and transferred to the plants of member companies. These examples of transferable technologies demonstrate the capability of COREM to impact the bottom-line of its member companies.INTRODUCTIONCOREM is a private mineral-processing R & D organization that operates from its own laboratories and pilot-plant with its own staff of professionals and technicians (about 95 persons). It is managed and financially supported by a consortium of nine mining and metallurgical companies and three provincial and federal ministries. The very ‘down-to-earth’ mission statement of COREM is to increase the competitiveness of the mineral processing plants of its members. The eighteen plants upon which the COREM technology development program is currently based can be found in Québec, Newfoundland and Labrador, New Brunswick, the Netherlands and Botswana."

Jan 1, 2010

By W. R. Green, B. W. Barde

"Geological exploration involves the collection and analysis of a wide variety of information. A basic problem in interpretation is to determine the interrelationship s of the different data. A number of statistical methods can be applied to this problem, provided that subsets of data can be selected.We have recently developed a set of interactive computer programs which provide the cap ability to quickly examine a large set of data, and may be used by people with little previous computer experience. There are two main stages in using this system. First is selection of subsets of data , by applying various tests on the values of given items. This includes matching specific entries in descriptive fields, and minimum - maximum tests on numeric fields. The second stage is basic statistical analysis and data display , including histograms, 2-D scalier plots, probability (cumulative frequency) plots, and correlation matrices. All output can be viewed on a computer terminal, and important parameters changed to produce the most effective display for use in interpretation.This system has been applied to a number of different exploration problems. An example was the determination of the nature and extent of mineralization of a gold prospect in the Queen Charlotte Islands, from drill-hole data. With the aid of the computer programs , a mineralized zone was defined, and locations for further exploration identified."

Jan 1, 1984

By Lam. E. K., J. W. Jarvi, B. P. Bharadwaj

"The Rabbit Lake Operation is located in Northern Saskatchewan on the western shore of Wollaston Lake approximately 800 km north of Saskatoon, Saskatchewan.The Operation is owned by a joint venture of Cameco Corporation and Uranerz Exploration and Mining Limited. Cameco is the operator.The Mill started production in June 1975 under the ownership of Gulf Minerals Canada Limited and over the past twenty years has increased the rated production capacity to over twice the original design.The Mill was originally designed to process 485,000 tonnes per year of ore with an annual production of 2.0 million kg of U308 (yellowcake). During the past ten years changes in ore sources and process modifications have led to increased milling capacity and production targets. The Mill has treated a total of 8.6 million tonnes of ore and produced over 40 million kg of U308 in the twenty year period, despite the shutdown and cutbacks in operating time since 1989.The 1995 tonnage throughput was 206,000 tonnes per year. Annual production though has risen to 3.6 million kg of yellowcake despite the departure from full-time to half-time operation in 1991 (7 up-7 down). The forecast for the coming years will see tonnage rising from 300,000 to 570,000 tonnes, production of 4.5 to 5.4 million kg of yellowcake and an anticipated return in the year 1998 to full time operation.This paper will give a brief history of the Mill and focus on the present flowsheet and recent improvements to the process."

Jan 1, 1996

By C. M. Davidson, D. J. Drexler

"Sulphuric acid treated with hydrogen peroxide to destroy organic contaminants could conceivably show increased corrosivity toward carbon steel shipping and storage vessels, caused by the persistence of a peroxide residual. This paper describes work performed to determine the effect of 0-200ppm hydrogen peroxide on the corrosion of carbon steel by 93% and 98% sulphuric acid at room temperature (23ºC) and 50ºC.Steel electrodes were exposed to acid containing several peroxide levels (0. 45, iOO and 200 ppm) for up to two weeks. Specimens were removed at intervals and weight loss, open circuit potential, depth of metal loss and residual peroxide concentration recorded.Hydrogen peroxide decomposes considerably over two weeks in iron-contaminated sulphuric acid. initial peroxide concentrations > l00 ppm suppress corrosion, but the effect is lost when concentration decays below about 60 ppm. Sustained peroxide levels in the range below 60 ppm may increase corrosion rates. These phenomena are interpreted by analogy with anodic passivation."

Jan 1, 1987

By K. J. Fair, H. W. Smith, D. R. Francis, J. M. Toguri

"Bench-scale batch milling and screening tests were carried out on secondary aluminum dross 10 produce an aluminum concentrate. To complement these tests, an analysis of a commercial plant was also performed by sampling dross at various stages in the plant's milling and screening circuit. These studies have indicated that benefits of increased capacity, grade and recovery of aluminum metal can be realized by addition of screens before the ball mill, longer grinding period and by grinding the smaller size fractions more efficiently.To test the predictions, a plant test was performed on the milling of100tons of secondary dross. The recycling of the large size fraction (+1/8 in.) of aluminum dross through the impact mill rather than through the rate limiting ball mill resulted in a comparable aluminum grade. The ball milling of the _1/ 8 in. + 10 mesh size gave a dross grade of71% AI. A lower feed rate to the ball mill resulted in a higher final grade. With minor modifications, secondary dross can be processed in 22% of the time it takes with the present circuit without a sacrifice in grade.IntroductionSecondary aluminum dross is a mixture of metallic aluminum, aluminum oxides and salts (alkali halides). Any comminution process deforms or slowly grind s the malleable metal phase and reduces the size of the friable, brittle, oxide-salt phase relatively fasterr(1).The milling of aluminum dross is performed to upgrade the metallic aluminum fraction. Figure I shows a flowsheet for the milling of secondary dross as presently practised at Metals and Alloys Co. Ltd., Toronto, Ontario. At point A, large acceptable grade material is hand picked for refurnacing, the unacceptable off-grade material is sent to the sweat furnace and the remaining, + 2 in. fraction is recycled through the 3.9 ft by 4.1 ft impact mill. For simplification, three ball mills are shown. However, in reality there is only one, a 5 ft by 10 ft ball mill used in a semi-batch mode. The 2 in. + 3/8in. and 3/8 in. + 10 mesh products are remilled in the ball mill. The -10 mesh material is discarded as waste."

Jan 1, 1987

By R. H. Batey

"The process control and cost of monitoring mining slurries is normally accomplished using a continuous mass flow system, conventionally embodying a volumetric magnetic flow meter and nuclear density meter. DuPont’s Maxville Mine at Starke, Florida, USA was chosen to examine costs associated with performance of a nuclear density meter. Since it is typical of many mid-sized establishments and has a long history in their use. The published accuracy under ideal conditions of a nuclear density meter is ± 1.0%, but in practice considerable ambiguity of cost in annual production implies ± 2% at best. Using such accuracy in a 400mm (16”) pipe carrying zircon slurry at 75,000 tons/day, the cost of ambiguity, together with initial and running costs, amount to nominally $962,000 per year.Such cost leaves much to be desired. This paper describes an unique continuous, direct mass per unit volume Density Meter used for mining slurries in pipe sizes up to 1000mm (40”), which significantly reduces the cost of ambiguity of measurement and running costs. At the same time the disadvantages of nuclear devices are obviated.In an effort to reduce costs, a 400mm non-nuclear Density Meter was installed at the DuPont Maxville mine. A typical on-site accuracy can be shown to be ± 0.285%, whereby the cost of ambiguity, initial and running costs in the example above shows an annual improvement of $78,660, a reduction of over $880,000 per year.Even higher cost savings may be demonstrated with mass flow systems having gas entrainment compensation. Unlike nuclear and other inferential density meters, the signal quality of this non-nuclear Density Meter is totally unaffected by entrained gas found in mining slurries. This non-nuclear density meter is then ideally used with a vortex velocity domain sonic flow meter, and provides for the first time compensation in wet density or dry % solids, as well as wet or dry mass flow of mining slurries with entrained gas, resulting in enormous reductions in cost ambiguity."

Jan 1, 2013

By Aparup Chattopadhyay, Barun K. Gorain

"Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.INTRODUCTIONA novel characterization tool has been developed for double refractory gold ores and complex copper-gold ores using state-of-the-art technology for quantitative gold and copper deportment study. The characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulphide phases and variable proportion of visible and invisible gold in different sulphides phases (pyrite, chalcopyrite, chalcocite and bornite) and iron oxide phases (magnetite, hematite and goethite). A study was initiated on various ore deposits and also on samples representing various processing streams of pilot plant batches such as flotation concentrates and tailings. This paper attempts to discuss the deportment characterization methodology through presenting results from investigations on four samples from a flotation circuit viz, Feed, Final concentrate, Cleaner Scavenger Tail and Rougher Tail samples. These four samples represent the key streams for a typical copper-gold flotation flow sheet. The key objective of this investigation was to identify and quantify visible and invisible gold along with understanding the morphology and liberation of gold associated with various sulphides, Fe- Oxides and non-sulphide gangue species. In addition, the aim of this study was also to relate this mineralogical and gold deportment information to metallurgical performance."

Jan 1, 2013

By Carlos F. Perucca

"Potassium is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production.Potash is extracted from buried ancient evaporites by underground or solution mining. This accounts for most of the potassium produced. Another important source is brine from landlocked water bodies, such as the Dead Sea, Salar de Atacama or Great Salt Lake.About 95% of potash produced worldwide is used in agriculture. The rest is found in several other industrial uses, including glass manufacturing, soaps, plastics and pharmaceuticals.Currently, three producers: IMC, PCS and Agrium operate 8 conventional and two solution mines in Saskatchewan, five of which run froth flotation circuits, two heavy media-flotation, two run forced crystallization and one natural crystallization.Potash in SaskatchewanPotash was discovered in Saskatchewan in the early 1940’s while drilling for oil. The deposits lie diagonally across the southern plains of Saskatchewan sloping southerly from a 1,000m depth at Saskatoon to more than 1,600 m depth at Belle Plaine and up to 3,000 m in depth in North Dakota. The known deposits are massive, accounting for more than 40% of the world’s known reserves."

Jan 1, 2003

By Robert E. McIvor

"The Functional Performance Equation for ball milling circuits allows us to isolate the circuit classification system efficiency (CSE) from the mill’s grinding performance. The factors which affect circuit CSE are reviewed, with emphasis on water usage at the classifiers. It is shown that manipulation of such water usage can be carried out to improve plant grinding circuit efficiency, at times by more than 30 percent.THE FUNCTIONAL PERFORMANCE EQUATIONObservation of the feed and product size distributions going into and discharging from the mill in grinding circuits with low versus high circulating load ratios initially led to the definition of “circuit classification system efficiency” (or CSE, McIvor, 1988a), and ultimately the discovery of the Functional Performance Equation (McIvor, 1988b, and McIvor et al, 1992). The CSE is the percentage of “coarse” (typically with reference to the plus P80) size material occupying the mill (versus “fines” or product size material, finer than the circuit P80), and can be calculated by taking the average of the percentage of coarse material in the mill feed and mill discharge. As this also represents the percentage of the mill energy expended on targeted, coarse size material, it is directly proportional to overall grinding circuit efficiency and production rate. This is all clearly expressed in the Functional Performance Equation for ball milling circuits, which is derived as follows.We define “fines” as any product size material, and “coarse” as that targeted to be further ground, the two typically differentiated by the circuit target P80. For any grinding circuit, the production rate of new, product size material (fines) must equal the specific grinding rate of the coarse material (i.e. fine product generated per unit of energy applied to the coarse material) times the power applied to the coarse material."

Jan 1, 2009

By T. P. R. de Jong, H. Harbeck

"This contribution reports recent mineral sorting experience and lists the opportunities of the newest generation of automatic sorters with a special focus on electromagnetic detection and Xray transmission. With the available sensor resolutions and actuator systems that are available today sorting of minerals down to 2 mm size and up to 250 mm lump size is technically feasible. In industry, ore as well as coal is still hand-picked and current automation potential only utilised in a handful of specific applications. Recently a number of technological developments took place that may increase sorting potential, save mill costs and lead to lower overall tonnage costs.They are:??High speed and high resolution sorting systems based on X-ray transmission imaging??High speed on-line image processing and further development of advanced data processing??Modular multi-sensor automatic sorting units (using one or more sensors such as colour, electromagnetic and X-ray in a single device)??Sensitive electromagnetic sensors for sorting based on differences in magnetic susceptibility and electric conductivityThe above enables compact dry separation, insensitive for moisture fluctuations and at high separation sharpness, as well as “electronic” high gradient magnetic separation for larger particles. Besides conventional X-ray transmission (XRT), dual-energy XRT (DE-XRT) is now being redesigned to meet the requirements of the mining industry. The mentioned technologies provide automatic dry separation of minerals and rock as alternative for conventional processing."

Jan 1, 2005

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 G. Belzil, F. Robichaud, M. Fullam

"The Goldex mining and milling complex is operated by Agnico-Eagle Mines Ltd. and is located in the Abitibi greenstone belt of Northwest Quebec, Canada. The mill operates presently at a throughput of 8,250 tpd with gold grade varying between 1.8 and 2.2 g/t. The ore is very high in gravity recoverable gold (GRG) at about 92% and as such a significant emphasis was placed on the gravity circuit. Commercial production started in 2008. Average gold recovery is 93.5% with about 68% of gold recovery coming from the gravity circuit. Over the course of the first several years of production, several gravity audits were carried out. In 2009, a complete gravity audit was completed, including ore, classification, Knelson Concentrators, and the gold room. In 2011, an audit was undertaken of the flotation circuit to determine the efficiency by which GRG is floated. Large samples of flotation feed and tails were collected and process for GRG content. This allowed a link between gravity and overall recovery to be made. This paper presents results of the audits and the development of a model linking gravity and overall gold"

Jan 1, 2012

By J. C. Escobedo, J. M. Almanza, A. Flores, Cortés. D. A.

Secondary aluminum dross, which has been exposed for several years to atmospheric conditions, was characterized using chemical analysis, X-ray diffraction, optical and scanning electronic microscopy, and energy-dispersive spectroscopy. Based on the characterization, a method to purify the solids is presented. This method starts with the washing of the dross in boiling water to eliminate the soluble compounds like Na and K, followed by the physical separation of the metallic aluminum by milling and screening. Finally, an acid lixiviation process is applied using three different acid solutions, HCl, HNO3, and H2SO4. The best results were obtained using HCl. The main insoluble components of the dross after lixiviation were Al, SiO2, and Al2O3. MgAl2O4, AlN, Si, and Na2Al22O3·2H20 species were also found. Based on the alumina content, the solid product could be suitable as a raw material in the manufacture of castable refractories or metal matrix composites.

Jan 1, 2005

By Bryn Harris, Liming Huang, Andre Laplante

"This paper reviews flowsheets generally used in gold rooms to upgrade primary gravity concentrates particularly those of Knelsons. It is concluded that even for small operations, which treat between 250 and lo00 kg of concentrates per day, there is a strong economic incentive to include in the flowsheet magnetic removal of tramp iron, at least two shaking tables, screening of either table feed or table tails at 150-212 um, and scavenging of table tails with a small centrifuge. Headroom, rather than floor space, is often inadequate in most gold room designs, and limits gravity flow and flowsheet flexibility. Experimental data are presented to demonstrate the effectiveness of a small Knelson Concentrator to scavenge significant amounts of gold (up to 91 %) from fine table tails.RésuméCet article examine les schémas d’évolution généralement utilisés pour traiter les concentres gravimétriques d‘or, en particulier ceux produits par concentrateur Knelson. Nous en venons à la conclusion que même pour un petit circuit d’une capacité de 250 A 1000 kg/jour pourrait bénéficier des opérations unitaires suivantes : concentrateur magnétique pour extraire la feraille, au moins deux tables A secousses, criblage de l’alimentation ou du rejet d’une ou des tables i une maille de 150-212 um, et épuisages des rejets fins de table avec un centrifuge de petite capacité. C’est l’espace vertical du lieu où se fait cette concentration qui représente la contrainte la plus importante, plutôt que sa surface, puisqu’il faut maximiser l’écoulement par gravite des pulpes et s’offrir une certaine flexibilité quant à l’agencement final des opérations unitaires. Nous présentons également des données expérimentales pour démontrer l’efficacit6 d‘un Knelson de laboratoire pour récupérer jusqu’ à 91 % de l’or contenu dans les rejets fins de table."

Jan 1, 1999

The information in this document has been prepared as at February 16, 2011. Certain statements contained in this document constitute ?forward-looking statements? within the meaning of the United States Private Securities Litigation Reform Act of 1995 and forward looking information under the provisions of Canadian provincial securities laws. When used in this document, the words ?anticipate?, ?expect?, ?estimate?, ?forecast?, ?will?, ?planned?, and similar expressions are intended to identify forward-looking statements or information. Such statements include without limitation: statements regarding timing and amounts of capital expenditures and other assumptions; estimates of future reserves, resources, mineral production, optimization efforts and sales; estimates of mine life; estimates of future internal rates of return, mining costs, cash costs, minesite costs and other expenses; estimates of future capital expenditures and other cash needs, and expectations as to the funding thereof; statements and information as to the projected development of certain ore deposits, including estimates of exploration, development and production and other capital costs, and estimates of the timing of such exploration, development and production or decisions with respect to such exploration, development and production; estimates of reserves and resources, and statements and information regarding anticipated future exploration; the anticipated timing of events with respect to the Company's minesites and statements and information regarding the sufficiency of the Company's cash resources. Such statements and information reflect the Company's views as at the date of this document and are subject to certain risks, uncertainties and assumptions, and undue reliance should not be placed on such statements and information. Many factors, known and unknown could cause the actual results to be materially different from those expressed or implied by such forward looking statements and information. Such risks include, but are not limited to: the volatility of prices of gold and other metals; uncertainty of mineral reserves, mineral resources, mineral grades and mineral recovery estimates; uncertainty of future production, capital expenditures, and other costs; currency fluctuations; financing of additional capital requirements; cost of exploration and development programs; mining risks; community protests; risks associated with foreign operations; governmental and environmental regulation; the volatility of the Company's stock price; and risks associated with the Company's byproduct metal derivative strategies. For a more detailed discussion of such risks and other factors that may affect the Company?s ability to achieve the expectations set forth in the forwardlooking statements contained in this document, see the Company's Annual Report on Form 20-F for the year ended December 31, 2009, as well as the Company's other filings with the Canadian Securities Administrators and the U.S. Securities and Exchange Commission. The Company does not intend, and does not assume any obligation, to update these forward-looking statements and information. Marc Legault, a Qualified Person and the Company?s Vice-President, Project Development, reviewed the technical information disclosed herein. For a detailed breakdown of the Company?s reserve and resource position see the February 16, 2011 press release on the Company?s website. That press release also lists the Qualified Persons for each project.

May 1, 2011

Brunswick Mine employs an ore and waste pass system for material transfer. This paper reviews the evolution and performance ore pass systems at the mine. It presents the range of selected configurations, inclination, dimensions etc. Select case studies are used to address the influence of structure, stress and materials handling on the longevity of the employed ore passes.

Feb 1, 2008

By Rob Sloan, Simon Yu, Rob Robison, Mark Schmidt

"In 2000-2009, Highland Valley Copper (HVC) tested new generation 660 mm cyclones supplied by various manufacturers in an aim to replace existing first generation 762 mm cyclones without success. Due to plant infrastructure limitations, new generation larger (838 and 800 mm) cyclones were not feasible. In 2010, an approach of testing hybrid 800 mm diameter cyclones was initiated by HVC. The hybrid cyclone consists of an 800 mm cyclone upper head section and the use of existing 762 mm cyclone conical sections. Three hybrid 800 mm cyclones were engineered and fabricated, targeting a throughput of 850-950 mtph and were installed in the E line cyclone cluster. Since starting operation on September 20, 2011, three hybrid 800 mm cyclones have been running at combined throughput ranges of 750 to 1050 mtph. Based on plant Daily Met Reports, the test hybrid cyclones demonstrated a decrease in misplacement of coarse copper bearing material to the cyclone overflow and better cyclone efficiency when compared to the existing 762 mm cyclones at the same throughput. The hybrid 800 mm cyclones also demonstrated significantly higher capacity per unit when compared to the existing cyclones. Based on the improvement demonstrated in the full plant trials, HVC decided to install the new hybrid 800 mm cyclones in all five grinding lines starting in July, 2012. A more detailed discussion of the full plant trials and initial results of the first complete retrofit of E line will be presented. INTRODUCTIONHighland Valley Copper Partnership (HVC) is Canada’s largest base metals mine and one of the world’s largest producers of Cu-in-concentrate. The mine, located in the central interior of British Columbia, is owned (97.5% interest) and operated by Teck Resources Ltd. In 2011, HVC produced about 210 million lbs. of Cu and 8 million lbs. of Mo. HVC’s Mill Modernization Project (MOP), which was budgeted for $475 M, is currently under intensive construction and is scheduled for commissioning in Q1 2014. The following description was valid at the time of writing this paper.The operation has been expanded a number of times since the startup of the original Lornex mill in 1972. The plant started up with two 9.75 m (32 foot) diameter primary SAG mills. It was expanded in 1981 with the addition of a 10.36 m (34 foot) diameter SAG mill. In 1988, the Highmont concentrator grinding mills and flotation section were moved and attached to the Lornex mill site. This added two10.36 m (34 foot) diameter AG primary mills to the Highland mill. This brought the total number of primary mills to five referred to as Line A, B, C, D and E: three SAG mills (A, B and C) each with two ball mills in parallel and two AG mills (D and E) each with one ball mill. Each AG mill line is equipped with one short head pebble crusher. Ball mill circuits are classified using 8 clusters of ten Linatex 762 mm cyclones to reach a target P80 330 micron (equivalent 43% +100 mesh), before the cyclone overflow product advances to the bulk flotation circuit."

Jan 1, 2013

By Jess Harding

Oyu Tolgoi investment agreement now in full, legal effect Successful completion of a series of conditions to 2009 Investment Agreement was announced March 31, 2010. Full-scale construction now set to begin. First copper-gold commercial production from Oyu Tolgoi expected in 2013. 34% of holding company Oyu Tolgoi LL Cacquired by Erdenes MGL, a Mongolian state-owned resources company. Remaining 66% will continue to be owned by Ivanhoe Mines. ?After 9 years of discoveries at Oyu Tolgoi, a big piece of the future of copper and gold in Asia is poised to become a reality.?

May 1, 2010

By C. Pelley, S. Kelebek, G. Kunzel, S. Gregersen, M. Pollanen

A series of small-scale tests was conducted to evaluate the effect of micro-fracture development, imposed by blasting, on the material properties of the rock as well as its resistance to crushing and grinding. The uniaxial compressive strength, tensile strength, Poisson’s ratio, Pwave, S-wave velocity, point load test index, crushing, and grinding work indices were evaluated for samples without any blasting load and for samples which had received a variety of blast loads ranging from a single impact with a lowstrength detonating cord to a combination of impacts at different times and significant impacts with powder factors close to those used in practical blasts. It was shown that the rock mechanics parameters change even at low impacts, suggesting easier crushing of the rock. Damage values appear to be affected by timing as stress wave superposition affects the damage process. Fragmentation is achieved at higher impact levels while work index modification of the fragments is also observed when high powder factors are used, suggesting improvements in grinding.

Jan 1, 2006