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By R. Jackman, D. Koningen, G. Wilcox

"Gowest Gold Ltd. is in the process of developing the Frankfield East gold deposit located along the largely undeveloped Pipestone fault northeast of Timmins, Ontario. In addition to resource development and environmental permitting work the company has had an ongoing program of metallurgical and engineering studies aimed at evaluating options for processing the Frankfield East ore. Mineralization at the Frankfield project contains arsenopyrite and pyrite as the major sulphide minerals. Bulk flotation of all sulphides results in extremely high gold recovery. However, the gold is almost entirely associated with the arsenopyrite fraction of the ore and is refractory in nature requiring preoxidation treatment. Selective flotation was investigated to recover a gold-arsenopyrite concentrate thereby reducing the mass which would be subjected to further gold processing. As part of this work, a pyrite concentrate low in arsenic content was also recovered that would be suitable as a source of sulphur for a smelter (or other pyrometallurgical facility). Production of separate arsenopyrite and pyrite concentrates is frequently examined but rarely adopted due to the distribution of gold between the two products or the inability to achieve adequate separation. Several flowsheet options were investigated in the study. The best results were achieved following a sequential flotation flowsheet. The flowsheet configuration was key to meeting the targets for the two products. In this paper, the various options investigated are reviewed and the results of the final flowsheet are presented. The overall plan by Gowest was to evaluate all process options to bring the Frankfield East deposit into production. The ability to effectively separate the arsenopyrite and pyrite components in the ore provides Gowest with added opportunities to pursue both short and long term production scenarios."

Jan 1, 2012

By Rocky (Yaokun) Wu

This paper introduces the development and application of a new cable anchor - Cable-Lok for pre-stressed cable bolting in mines. Cable-Lok is a spring-loaded cable anchor suitable for the drill hole diameter of 50 and 65 mm (2" and 2.5") in medium soft rock to hard rocks. The cable anchor is automatically set on installation and the cable can be tensioned immediately to provide active and primary support throughout its length. Post-grouting can be conducted independently. In comparison with the conventional cable bolting, Cable-Lok anchor will greatly speed-up the cable bolting circle and decreases the cost of cable bolting. Cable bolting anchored with Cable-Lok anchor has wide application in mines, e.g. pre-stressed cable bolting in large span drifts and intersections for permanent rock support, or in hanging walls or stopes for temporary support, or cable lace anchoring etc. This paper introduces the principle of pre-stressed cable bolting and the specifications of the Cable-Lok anchor, presented the testing results in laboratory and the application cases in mines.

Oct 1, 2010

By Alain Bouchard, Germain Labonté, Jim Barrett

"Mill feed materials that are not run-of-mine ore are often a challenge for mineral processors and tend to accumulate in stockpiles, where they remain unprocessed for many years and become “slow moving inventories”. During a complete re-evaluation of the Clarabelle Mill operation (38,000 ton/day capacity) in 2000, it was concluded that there was an opportunity to assemble a 5,000 ton/day custom circuit to treat such stockpiles in the equipment that remained available during regularly scheduled maintenance shut-downs.This project was part of the larger Mill Redesign Project and involved testing the intended flowsheet under a number of operating scenarios for the first material to be treated: spent refractory bricks. The laboratory focus was on how to maximize returns using the available equipment and reagents.The circuit was successfully commissioned in the fall of 2000. As the brick stockpile was depleted, other potential feeds were evaluated at the laboratory, as well as in the new custom circuit itself. Processing of the spent refractory brick has yielded a significant contribution to the profitability of INCO. Significant opportunities lie ahead for generating more value from other slow moving inventories.INTRODUCTIONIntegrated mining operations tend to have slow moving inventories along the path from the mines to the finished products. Spent refractory bricks from furnaces and converters and furnace bottoms are materials that often end up in long-tern stockpiles. Such stockpiles are a challenge, although they represent small tonnages on an annual basis, because they are unique materials, which cannot be readily brought into the process at a rate anywhere near that at which they are produced, due to the high contents of deleterious components such as chromite or magnesia. Accumulation over years will eventually yield a metal inventory worthy of consideration given the right opportunity, such as availability of spare equipment or peak metal prices."

Jan 1, 2002

By L. J. Heaslip, J. M. Toguri, T. R. Meadowcroft, R. L. Addinall

"""Pilot Plant Operations"" is a final-year core course given to the Metallurgy and Materials Science students at the University of Toronto. This course involves a laboratory study of an industrial project at an industrial site. Details of this program are discussed and reviewed after eight years of experience. IntroductionEducators in the field of Metallurgy and Materials Science have long agreed that ""hands-on"" experience is an important component in the education of metallurgical engineers. This philosophy is reflected in the undergraduate curricula of most metallurgical schools. The major problems encountered with laboratory-associated courses are the requirements for equipment, space and funds for both purchase and maintenance of equipment. For example, consider an exercise in crushing and grinding treatment in a mineral processing laboratory. Such operations require the handling of tons of material and often equipment of large size. The problems of storage of ore, methods of handling and maintenance of equipment are a few of the concerns facing the department. Considering that metallurgical departments at universities are, in general, relatively small, the support to purchase and maintain largescale equipment becomes an annual budgetary concern. In reality, universities today are not geared to operate mini-pilot plant equipment, either in terms of space or personnel.For the above reasons, in 1972an undergraduate core course called ""Pilot Plant Operations"" was introduced to the fourth year curriculum in Metallurgy and Materials Science at the University of Toronto. This course consists of I to 2 full weeks (8 hrs per day) of pilot plant laboratory study at an industrial site on a project of mutual interest with the industrial organization whose facility is being used. The first 5 years of the program were carried out at the pilot plant facility at the Ontario Research Foundation; Stelco's Research Centre in Burlington, Ontario, was used for the last 3 years. The nature of the projects undertaken during the 8-year period is shown in Table 1."

Jan 1, 1980

By A. Lewis, J. Zachwieja, M. Widell, P. Zhou, W. W. Geissler, M. Svensson, A. Movahedi, H. Nordberg

Flotation collectors for sulfide minerals has been traditionally based on xanthate, thiophosphate, thiophosphinate and thiocarbamate, all derived from sulfur chemistry. Tecflote™ is a new family of patented collectors based on nitrile chemistry which can supplement or replace thiol collectors, depending on the ore types. A steep grade-recovery curve typical of Tecflote™ collectors was observed when using Tecflote™ as the main collector for the rougher and cleaner steps allowing a better recovery compared to current thiol collectors while maintaining the desired grade. Additional recovery increase has also been observed by the addition of scavenger steps using Tecflote™ collector in combination with current thiol-based collector. The selectivity seen in the lab is transferred to full scale trial and is clearly seen in the rough flotation where the increase in the rough concentrate grade of 5% after pumping Tecflote S11 directly into the tank cell. The mechanisms for Tecflote’s selectivity towards sulfides are currently under investigation and will be discussed. Results of TOF-SIMS analysis will be presented, demonstrating the collector’s selective affinity to different mineral surfaces in flotation. INTRODUCTION The history of collectors used today started in 1882 when Zeise first made xanthates. It was first used in flotation in 1925 – Cornelius Keller’s first patent (Fuerstenau, Jameson, Yoon, 2007). Between 1928 and 1930 American Cyanamid filed 7 patents for dithiophosphate, including flotation and chemical synthesis of the reagent, the first of which was filed by Christmann in 1928 (Christmann, 1933). Synthesize of thionocarbamates for mineral flotation was filed in 1954, by Dow Chemical Company (Harris, 1954). Now that the head grades have been declining over the last decades the need to find more selective collectors to extract difficult and complex ores has pushed the industry to look at different chemistries. Thiol collectors standard to the industry rely on the sulfur in the collector molecule to bond to the mineral surface. The electronic property of this group is modified by the adjacent chemical groups, such as additional S, P or N have the effect of changing the selectivity of the collector (Wills & Finch, 2016). In the case of xanthate the length of the hydrophobic group also has an effect on the selectivity with some minerals such that the ethyl xanthate is more selective against pyrite and pyrrhotite than the long chain xanthates (Wills & Finch, 2016).

Jan 1, 2019

By Jason J. Crowder

Presentation Outline ? Introduction ? Costs of ground support and rehabilitation ? Why post-failure rock mass properties are necessary ? The Rock Mechanics Problem ? Present State of Modelling and Instrumentation in Mining ? Case Study Background ??Williams Mine ? Deriving Parameters for Modelling from Instrumentation ? Results from Case Study ??Back Analyses ? Discussion of Research Impact t Summary

May 1, 2006

By A. Tylczak, C. Norman, C. Shook, S. Loif

"There are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes or malfunctioning equipment early, which allows problems to be corrected promptly.Sacré-Davey Engineering in Vancouver has performed over 50 Energy Management studies for various industries including: mining, pulp and paper, oil and gas, etc. Energy Management programs can be used to identify energy reduction opportunities, assess project feasibility, complete equipment selection trade-offs, as well as to monitor and manage energy costs. Benefits of energy management programs are reduced energy costs, reduced maintenance, and increased plant automation. Additionally, energy management can provide access to utility incentive funding and quantify savings which can greatly improve the return on investment of potential projects.Energy management studies are funded by many Utility programs across Canada. There are various programs available for existing plants energy audits, project feasibility studies, new plant design reviews and energy monitoring and targeting, etc. There are capital incentives available which can significantly reduce payback period.This paper discusses how energy management can be used to support mill/mine operations groups, maintenance programs, as well as expansion or green field projects. This paper will also provide an overview of Canadian Utility companies programs and how they can assist mining companies.IntroductionThere are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes and identify malfunctioning equipment early, which allows problems to be corrected promptly."

Jan 1, 2015

By P. V. Avotins, I. Djurkovic, D. R. Nagaraj, M. Grunjic, A. Day

"As part of a major reconstruction and expansion of the Majdanpek Copper Mine, an investigation and optimization of the flotation collector regime was undertaken. The flotation response of the major minerals to various reagents and the effect of pulp chemistry was studied from both a fundamental and practical point of view. These studies led to plant trials and the eventual adoption of a modified collector suite which improved both copper and gold recoveries.INTRODUCTIONThe Majdanpek Copper Mine processes 40,000 tons per day of ore containing about 0.43% cu. In addition to copper, the ore also contains recoverable quantities of molybdenite and gold. The mine has been in operation since 1961 and is the largest in Yugoslavia. It is currently undergoing major reconstruction and expansion. The flowsheet of the Majdanpek concentrator is shown on Figure 1.The ore body is variable in composition and changes in mill feed require proper control of operating variables to achieve the optimum metallurgical results. A detailed study including grindability, flotation response, and solid-liquid separation was carried out on several samples of the ore. Flotation response and the choice of reagent chemistry were found to be very important in achieving the highest recoveries of metal values. An automatic reagent control scheme insured that optimum dosages were used in the plant.The flotation collectors used at the present time include sodium isopropyl xanthate (SIPX), AERO 3302 Promoter and AERO 5415 Promoter. The addition of AERO 5415 to the reagent suite is a recent development and was based on the favorable results obtained in the extensive laboratory testing program conducted to establish the optimum reagent combination and dosages. Subsequent plant tests confirmed that AERO 5415 provided significant improvements in copper and gold recoveries. A description of the mineralogy of the Majdanpek ore and details of laboratory and plant metallurgical data are given in this paper. The chemistry of AERO 5415 Promoter and its interaction with minerals relevant to Majdanpek ore are also discussed."

Jan 1, 1992

By Donald Leroux, Colin Hardie

"New or improved mathematical models of mineral processing machines are published almost on a monthly basis. Often, these models can be calibrated from bench-scale test results and programmed using spreadsheet software to simulate different designs and operating conditions in open-circuit configuration. However, since mineral processing plants frequently operate comminution, separation and/or extraction machines in closed-circuit configurations, open-circuit simulations often have limited applicability.The simulation of closed-circuit configurations necessitates the programming of an iterative loop to bring the circuit to equilibrium. This can be done by using spreadsheet software but often requires advanced programming skills. As an alternative, LIMN® software, which simplifies the programming of closed-circuit configurations within spreadsheets can be used. This software was specifically designed to turn a Microsoft EXCEL® spreadsheet into a closed-circuit modeling and simulation platform with minimal programming.During the past few years, the Mineral Processing Group at the Noranda Technology Centre, has used this software for numerous projects which include the simulation of multi-stage cyclone circuits, closed-circuit regrinding and locked-cycle flotation tests. Using these projects as examples, the flexibility and the easy to use nature of the LIMN® software is demonstrated.INTRODUCTIONMineral processing engineers routinely have to make predictions regarding comminution and separation processes. Predicting the appropriate dimensions of equipment and the process response to changes in operating mode are probably the most common situations that they face. In all cases these predictions are expected to be rapid and accurate.Predictions made by engineers are frequently based on mathematical models. Many first principles, empirical, semi-empirical, steady state and dynamic models of mineral processes can be found in the literature. In fact, new or improved mineral processing models are continuously being proposed and in spite of this variety, process engineers often have to either develop their own or tailor existing models to suit their particular needs."

Jan 1, 2003

By Patrick J. Williams, Peter J. Pollard

"Abstract - Enigmatic hydrothermal vein/breccia/replacement Cu-Au deposits with magnetite and/or hematite are well-represented in Australian 1850 Ma to 1500 Ma terrains and associated with different-aged synorogenic intrusions in the Tennant Creek Block (ca. 1850 Ma); the Gawler-Curnamona region (1640 Ma to 1590 Ma); and the Cloncurry district (Mount Isa Eastern Fold Belt, 1540 Ma to 1500 Ma with a possible earlier event at ca. 1600 Ma). No deposits are known to be coeval with various 1780 Ma to 1610 Ma anorogenic intrusions. Deposits are hosted by many different rock-types with varying metamorphic grade including granites and various supracrustal rocks. Depth of mineralization varied from many kilometers in semiductile crust (e.g., Cloncurry deposits) to very shallow (e.g., Olympic Dam). Ore deposition near Cloncurry occurred in brittle-ductile shear zones from geochemically variable and complex, CO2-rich, 300°C to 500°C, high salinity fluids with magmatic stable isotopic signatures. Recently published studies of a giant granitoid-hosted magnetite vein complex at the Lightning Creek prospect (>1000 Mt magnetite) suggest it is a product of internal differentiation and endogenous Fe and Cu-rich hydrous-carbonic fluid phase generation within a quartz monzodiorite-monzogranite intrusion. Coupled with other field relationships, this points to a possible genetic relationship with intermediate (55 to 65 wt% SiO2) members of an alkaline and partly shoshonitic granitoid supersuite which appears to have both mantle and crustal source components from ?Nd evidence. In constrast, main-phase mineralization at Olympic Dam in the Gawler Craton is distinguished by hematite-phyllosilicate alteration and chalcopyrite-bornite-chalcocite zoning, reflecting fluid mixing in a high level (<250°C) system with a probable large component of meteoric water. Early high-temperature parageneses and fluid inclusions imply that the extensive hematitic breccias overprinted an older magnetite system which may have had similarities with those at Lightning Creek and Ernest Henry in the Cloncurry district.Deposits of this family are inherently difficult to find and evaluate as even within a single district, there is no reliable relationship between the location of ore and any specific combination of geophysical characteristics. Diverse alteration assemblages, geochemistry and physical characteristics suggest the deposits reflect the interaction of multi-sourced fluids with different host rocks in a wide range of geological environments. Recent discoveries and research in the Cloncurry district have extended the range of deposit models available and aid the development of a rudimentary classification in which economic and exploration characteristics can be linked to variations in the mechanisms and environments of ore formation."

Jan 1, 2001

By K. Woo

The increasing move to block cave mining methods (including sublevel and panel caving) to access deeper and lower grade ore deposits as near surface sources become exhausted raises questions as to the extent and magnitudes of caving-induced subsidence as it may affect strain-sensitive infrastructure on surface. Predicting these surface deformations is difficult as they tend to be discontinuous and asymmetric due to large movements around the cave controlled by geologic structures, rock mass heterogeneity and topographic effects. Of further impediment is the sparse number of case histories available, in which actual subsidence measurements are reported to provide guidance and empirical constraints for subsidence calculations. This study reports the development of an exhaustive and comprehensive database of available (i.e. public domain) subsidence data from block cave mining operations from around the world.

May 1, 2009

By Neil McMillan

"By any measure of common practice, Claude Resources' Seabee Gold Mine in Northern Saskatchewan should not now be operating. Not because reserves dwindled, or grade dropped or prices weakened or technical problems arose, but because a host of unimaginable other problems beset the project, any one of which would normally have led to the mine's failure.The success of the Seabee Mine, and it is extremely successful, is a story of the vision and blunt determination of two men. Neither is remarkable in his own right but each possesses the characteristics which were necessary to forge a highly productive and profitable narrow-vein mine in the midst of the most bizarre and unpredictable events which likely have ever beset a mine start-up in Canadian history.Together, Bill MacNeill, a Saskatchewan born, former bush pilot and Ray Gagnon, a big hearted, hard-fisted, miner with 44 years of experience in Canada's underground, built the Seabee Mine.They didn't accomplish this with brilliant geology, outstanding engineering or nimble corporate manouvering but rather a stubbornness and raw common sense which likely are all too often, ingredients missing in failed projects.The Seabee Mine is 100% owned by Claude Resources, a Saskatoon based company taken over by Bill MacNeill, its current chairman, in 1982. The company is listed on the TSE and produces 1200 barrels of oil per day and about 60,000 oz of gold per year. The company has a strong balance sheet, is very profitable and has 18 million shares outstanding.The Seabee property in Northern Saskatchewan started out like many other gold exploration properties in Canada.It was discovered in the l 940's by what is now Cominco, and, while highly regarded by that company the property sat largely dormant until acquired by Claude Resources in 1985.Claude did what most junior exploration companies would do and went looking for a company with a depth of expertise to joint venture the property.That company was Placer Development who could earn a 55% interest in the Seabee by delivering a bankable feasibility study on the Project by July 1988 and providing financing to production.Placer Development was an excellent company and spent over $8 million dollars on the Seabee over a 3 year period. Unfortunately for Claude Resources, Placer Development merged with Dorne Mines in 1987 and the new merged company, Placer Dome, established a minimum production threshold greater than the 50,000 oz per year which the Seabee appeared capable of supporting at that time. Placer Dome's request for an indefinite extension of the joint venture agreement to allow it to drill off a larger ore body was rejected by Claude Resources and the Seabee Property was returned to Claude in 1988."

Jan 1, 1998

By Robert J. Maron, Mark Fernald, Alex Van der Spek, O’Keefe. Christian, Tim Bailey

"Sonar array-based non-invasive flow measurement technology is becoming an accepted and many times a preferred method of measuring challenging single and multi-phase flows in the mineral processing industry. This fundamental sensor and measurement technology has been extended to two developments that provide new measurement capabilities useful for monitoring and managing slurry flows and pipes.The first development is the non-invasive measurement of real-time velocity profile of slurry flow in horizontal pipes. Multiple non-invasive passive sensors measure localized velocities and are combined to provide a velocity profile measurement. This information can be used to determine the approach and onset of solid deposition on the bottom of the pipe. Having this information in real time can enable operation at lower velocities and/or higher solids concentration while avoiding solids deposition or plugging and its associated operational costs.The second development is the non-invasive measurement of pipe wear on slurry lines. Presently, such measurements are made by hand-held portable ultrasonic thickness gages. The numerous shortfalls associated with the manual method are overcome with a set of permanently or semi-permanently installed transducers clamped onto the outside of the pipe. This ring of sensors contains a series of conformable ultrasonic transducers spaced around the circumference, which are used to measure the thickness of the pipe under their respective locations. Compared to manual methods, this system and approach results in better repeatability and accuracy. It also decreases inspection labor costs and pipe access requirements. The minimal accuracy variations in the presence of varying environmental temperatures will be shown. Trending of pipe wall thicknesses in high wear pipelines will be illustrated. The benefits of significantly improved pipe wear monitoring in hydrotransport lines with abrasive solids, and associated improvement in the ability to insure safe operation and avoidance of costly environmental damage due to leaks caused by pipe wear will be discussed."

Jan 1, 2009

By A. Griffiths, G. Vickell

"INTRODUCTIONA successful cyanide destruction process has to ensure environmental compliance at reasonable cost. That this is possible with hydrogen peroxide is shown by the fact that over twenty gold mines either already use H2O2 or intend to start using it within the next few months. About half of these mines are in Canada.This growth is remarkable, considering that the first treatment plant to use H2O2 for detoxifying cyanide was commissioned less than five years ago at Ok Tedi, in Papua New Guinea.Hydrogen peroxide is being applied to a wide range of situations, including:Treatment of CIP pulps; examples: Ok Tedi, PNG; Hope Brook, Nfld.Treatment of barren bleeds and filtrates; examples: Nickel Plate, B.C.; Puffy Lake, Man.Treatment of tailings pond discharge; examples: Detour Lake, Ont., Page Williams, Ont.Treatment of excess heap leach solution; examples: Hope Brook, Nfld; Gordex, NS.Treatment of barren heaps after heap leaching; examples: Alhambra, NV; Wharf Resources, S.D.Treatment of pond reclaim water to prevent either ""preg-robbing"" or depression of gold-bearing pyrite in a flotation step; example: Getchell, NV.Treatment of backfill to prevent possible groundwater contamination; example Hope Brook, Nfld.Treatment of tailings ponds to prevent bird kills; example: Paradise Peak, NV.""Emergency"" units to deal with unusual events such as freak storms or dam failures."

Jan 1, 1989

By Brad E. Melanson

Because mine haul trucks consume considerable quantities of fuel, they are ideal candidates for the adoption of cleaner and cheaper fuels like natural gas. Impressive fuel cost savings will be realized in regions where liquefied natural gas (LNG) has cost advantage to diesel fuel, while also providing significant reductions of air contaminants and greenhouse gases. High Pressure Direct Injection (HPDI) of natural gas utilizes the diesel cycle combustion process and therefore retains the diesel engine?s high performance and efficiency characteristics. HPDI has been demonstrated in on-road Class 8 trucks since 2001 accumulating almost 10 million kilometres to date. The supply of LNG fuel will be an essential parallel aspect in the introduction of HPDI to mining. LNG can be transported to site as diesel is today, or may be produced on or near mine operations that have access to methane sources or pipelines.

May 1, 2006

By Rodolfo Espinosa Gómez

"Industrias Peñoles, S.A. de C.V. – Mining Division, has initiated in the last ten years, six Mining Operations (Bismark, Tizapa, Ciénega, La Herradura, Rey de Plata, and Francisco I. Madero) and it has expanded several of their existing Operations (Sabinas, Fresnillo, Tizapa, Ciénega) one or more times.This work aims to share the experiences learned on this growing process. Some of these lessons are: 1) Project leaders must have a leadership that fosters good communication and team work; and this leadership style must come from top management. 2) A good communication must exist between the personnel from Engineering, Construction, and Operation. Also, this good communication must come from top management. 3) Starting the project with a solid Engineering Study. 4) Do not misunderstand cost with cost/benefit; always look at the cost/benefit. 5) Selecting good Contractors and good Suppliers. 6) Good training before the project commissioning is essential to reduce the learning curve period, this is even more important in areas where local people do not have any background in mining activities. 7) Recognizing that any project has a learning curve and it must be reflected on the production budget. 8) Avoid an over optimistic Mine preparation time schedule.BACKGROUNDIndustrias Peñoles S.A. de C.V.The mission of Industrias Peñoles, S.A. de C.V. (Peñoles) is to add value to non-renewable natural resources in a sustainable manner. Peñoles seeks to build long-term shareholder value; provide their customers with the highest quality products and services; maintain productive longterm relationship with their suppliers; develop and promote the capabilities of their personnel; foster mutually beneficial relationship with the communities in which it operates, and preserve the environment.Peñoles was established on 1887. It is a Mining Group with integrated Mining, Smelting and Refining operations of non-ferrous metals, and also produces inorganic chemistry materials. Peñoles is the main World producer of refined silver, metal bismuth, and sodium sulphate; Latin American leader in the production of refined gold, lead, and zinc.The Mining Group is made-up of nine mining operations producing concentrates with high gold, silver, lead, zinc, and copper contents. It produced in 2002, 365,900 ounces of gold; 52.7 million ounces of silver; 86,820 tonnes of lead; 266,000 tonnes of zinc, 11,840 tonnes of copper; with a total values of 3,780.6 million of Mexican pesos (~ $ 378.0 million U.S. Dollars)."

Jan 1, 2004

By George Chung

"The Iron Ore Company of Canada's Carol Lake Project is Located near the western boundary of Labrador, 960 air kilometers northeast of Montreal (Figure 1).The Concentrator operation was started in 1962 with a capacity to produce 7 million tonnes of concentrate per year. The bulk of the concentrate was pelletized at a 6 million tonnes per year pelletizing plant completed in 1963. The remaining concentrate was sold in the international market. The concentrator was first expanded in 1966 to 10 million tonnes per year capacity with the pellet plant also expanded in 1967 to match the increase in concentrate production. In 1973, the concentrator was further expanded to gear with the increase in concentrate sales. In 1977, more than 40 million tonnes of crude ore was processed to produce in excess of 17.4 million tonnes of concentrate and 10.4 million tonnes of pellets."

Jan 1, 1980

By Dayle Denton, Lloyd Buckingham, Kenneth G. Thomas, Jacques McMullen

"The dry grinding and leaching circuits of Barrick Gold’s new Roasting Facility at Goldstrike Mine in Nevada, USA incorporate well proven technologies in a unique combination. During the design of the plant, every effort was made to utilize the best available technologies from the perspective of capital, environment and operating costs.Crushing is a two stage process using gyratory and cone crusher. Ore is stockpiled and then reclaimed to two parallel dry grinding mills. The double rotator dry grinding mills include a drying chamber, coarse and fine compartments and utilize a gearless motor drive (GMD) or “wrap-around”. In-circuit product transfer is accomplished with air slides and bucket elevators. Finished product separation is performed by both static and dynamic classifiers with the final product captured in baghouses. Recycle of unfinished product utilizes cascade chutes.The final ground product reports to two 2000 ton roaster feed silos. The two-stage oxygen flu-solids roasters with their associated gas train are the subject of a separate paper.The cyanide leach circuit is a standard carbon in leach system with circular swept screens for interstage carbon retention. The loaded carbon is sent to the existing Goldstrike autoclave plant for stripping and regeneration. Tails, after cyanide destruction, are deposited in the existing tailings dam with tails from the autoclave facility.Throughout the circuit, Clean Plant Design criteria were used to assure environmental compliance, ambiental acceptability and ensure worker health and safety. The commissioning and operation of the double rotator grinding technology has been very successful at Barrick Goldstrike."

Jan 1, 2001

By James F. Archibald

In historic mining practice, typical thin liner support systems have been considered to comprise non-reinforced or mesh-reinforced shocrete linings. In the early 1990?s, development of alternate forms of liner systems was initiated in Canada which is now undergoing significant international growth in countries which sustain major mining activity. Now internationally designated as thin, spray-on liner systems, a wide spectrum of liner materials, ranging from liquid/liquid to liquid/solid component combinations, has become commercially available. This innovative family of products is characteristically identified as being rapidly deployable, capable of creating ultra-fast setting coverage over rock surfaces, and able to develop tenacious adhesion and pull strength capacities for resisting rock falls and movements. This paper presents a summary of current liner developments and use in principal mining districts world wide. Additionally, a database of material properties for principal product types used in mining and a review of common quality control testing procedures under development are provided. Such information is based upon recent Canadian and international efforts being taken to assess and develop user standards for the implementation of thin, spray-on liners as rock support in mines. This work is intended to continue for a period of years, with the eventual goal being to establish support and installation guidelines for mines based on quantifiable laboratory and field research.

May 1, 2002

By C. Patel, George H. Hope

"INTRODUCTIONThe Hemlo area is located in Northern Ontario, some 350 km east of Thunder Bay along highway 17. Hemlo is Canada's largest, recent discovery of gold ore. Three companies, Lac, Noranda, and Teck are currently developing mines and processing facilities in the area. A combined milling capacity of approximately 10,000 tonnes per day will ultimately be available in the area. The gold yield will be between 750,000 to 1,000,000 ozs. per year. This will slightly more than double Ontario's gold production but only represents 2.5% of the total world gold production.Lac Minerals Ltd. is substantially committed to the gold mining business. Lac currently operates four (4) gold mines and mills and produces 300,000 ozs. per year. Lac's Hemlo development will put the company in the position of number one gold producer in Canada.The Lac Hemlo ore body has an estimated reserve of 37 million tonnes at 6.2 g/t. The mining will take place at an initial rate of 3,000 t/d commencing in the first quarter of 1986. The mine and plant will be expanded to 6,000 t/d in 1988. At this capacity, Lac will be the largest producer in the Hemlo area.1. GEOLOGYThe orebody is divided into two (2) zones for mining purposes. The 'A' Zone is to the east and dips to the Northeast from surface to 300 m below surface. This zone has a strike length of 250 m to 300 m at an average width of 20 m. The upperpart of the zone will be mined by open pit and the remainder from underground. The 'B' Zone, to the north west of the 'A' Zone, although lined up is not necessarily an extension of 'A' Zone. 'B' Zone has a known strike length of 600 m and is open to depth and along the strike. It is over 70 m wide in the core. This zone holds most of the property's known reserves. 'C' Zone with narrow gold zones is under exploration in the south west portion of the property."

Jan 1, 1985