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By L. Janku, G. Hancox, M. Villenueve, C. Massey

Wellington lies in a seismically active area 150 km from a subduction zone and in the vicinity of several active faults, which poses a risk to its infrastructure and inhabitants. One of these major faults, the Wellington Fault, runs through the centre of the city and across several lifelines, including the natural gas pipeline and the freshwater pipeline. The first settlement in the area was severely damaged in 1848, soon after its establishment, by an earthquake of approximate magnitude Mw 7.4 - 7.5 (Grapes, Little, & Downes, 1998). In 1855, another earthquake of magnitude Mw 8.2 generated by a nearby fault uplifted the eastern part of the current Wellington area and caused several landslides in the surrounding hills (Grapes & Downes, 1997). The Central Business District lies in the area of a sedimentary basin and partly on reclaimed land. Many residential areas, as well as some vital infrastructure, however, lie on or along the slopes in the surrounding hills. The bedrock in the area comprises predominantly the Torlesse greywacke of Permian – Late Triassic age. The greywacke is tilted to a steep angle, intensively faulted and fractured (Cook, 2001). Even though several studies in the past assessed the seismic risk in the area (e.g. Brabhaharan, Hancox, Perrin, & Dellow, 1994), the studies either focussed solely on the area of the sedimentary basin or based their assessment of the hilly terrain purely on slope morphology (slope angle). Previous studies have shown that slope shape and contrasting materials in the slope can amplify earthquake ground motions, such factors are typically called site effects (e.g. Geli, Bard, & Jullien, 1988). Any attempt to systematically quantify the site effects and consequent seismic response of the slopes and use it to predict the consequences of the next large-magnitude earthquake, has not yet been carried out. In this extended abstract we outline the methodology of a PhD research project, focussed on investigating the site effects on the slopes around Wellington and on creating representative numerical models of ‘characteristic’ Wellington slopes and materials. This extended abstract presents the methodology adopted for the assessment using the Te Ahumairangi Hill site as an example.

Jan 1, 2015

By \/eena Sahajwalla, Jonathan Dicker, Paul O'Kane, Cath Skidmore, James Dankwah, Magdalena Zaharia, Rita Khanna, David Knights, N Saha-Chaudhury, Somyote Kongkarat

Due to the inherent limitations of current methods of disposal of end of life polymeric materials, avenues are researched towards developing alternative, environmentally friendly and economic recycling processes. Different polymeric materials (i.e. rubber, high density polyethylene (HDPE) and polyethylene therephtalate (PET)), quite distinct in terms of chemical structure and composition, were considered in the present study as carbon resources in EAF steelmaking. Investigations were conducted in both laboratory and industrial scale steelmaking to assess the effectiveness of using these materials as carbon sources for slag foaming in EAF steelmaking. Slag foaming is important because it enhances furnace efficiency.

Jan 1, 2011

The Anglo Platinum Mogalakwena North concentrator was one of the first three hard rock mineral processing applications to utilise a HPGR circuit in preference to a SAG milling circuit. This was driven by the extreme competence of the ore that had given rise to throughput issues on the original South Plant. Despite more than adequate capacity and performance of the individual comminution units, the circuit has struggled to obtain full design capacity. A thorough review of the integrated performance of the circuit revealed a wide range of bottlenecks and underutilised parts of the circuit arising from design issues. Interestingly, the major opportunities lie in materials handling issues and mismatch of loads about the circuit. This paper presents the high-level outcomes and the associated opportunities, and is pertinent to all HPGR circuit designs.

Jan 1, 2012

By W. M. Goodwin

The gold district of northwestern Quebec, though it has attracted such widespread attention during the past year, is still in the prospect stage throughout, and one must preface any remarks about it with the plain statement that its capacity to produce gold commercially is still subject to proof. However, this proof may be forthcoming any day, and from widely separated localities. Consequently it is of interest to note some of the features of the region and of the prospects now being developed. First I shall note the relation of this mining development to the province of Quebec and to the Dominion; then will follow a brief resume of the known geological facts; and finally I shall describe briefly some of the more advanced prospects developed during the past twelve-month. Those that have followed closely the fortunes of the new gold-field will find little that is new in what follows, but it may serve a useful purpose for others by bringing together scattered items of information and presenting them as a whole. GOLD MINING AND AGRICULTURE First let us consider the gold belt in its relation to the province of Quebec. Apart from the world-renowned asbestos camp south of the St. Lawrence, it is the only mineral development of major importance the province has experienced. It is the first important development in the province's vast area of Precambrian rocks, most of which remains as yet totally unexplored and unprospected. The relative importance of this first mining camp in northern Quebec cannot as yet be gauged, but it is bound to stimulate an active interest in the other mineral-bearing areas now known to exist, and in the vast unexplored spaces.

Jan 1, 1924

By W. A. Dixon Edwards

Industrial mineral production in Alberta, worth $468 million in 1997, comes from a dozen types of industrial minerals, mined by about 400 producers. Cement and lime from Paleozoic limestone formations exposed along the Rocky Mountains account for the greatest production value. Sand andgravel is the primary source ofmineral aggregate. Almost two-thirds of this aggregate is consumed in the Edmonton and Calgary regions. Sulphur produced at 48 sour gas processing plants and two oil sands plants was valued at $84.8 million in 1997 and accounted for 80% ofCanadian sulphur production. Four companies solution mine the Elk Point salt beds to produce chlor-alkali chemicals, industrial salt and sodium chlorate. Natural brine is also produced as a dust control product. Al $22 million, peat moss is a major industrial mineral product in Alberta. Other minerals with noteworthy production include shale, stone, silica and ammolite. The commodities with the greatest development potential are diamond, silica and oil sands tailings by-product minerals.

Jan 1, 2001

Adsorption of guar gum was investigated on model minerals typically found in water-insoluble slimes of potash ores. The ionic strength of the adsorption mixtures was varied from distilled water to saturated NaC1 and KC1. The tests were also performed using a saturated brine. The adsorption density of guar gum on illite, dolomite, and kaolinite was found to be not only a function of total ionic strength but also of the type of electrolyte present in solution. Generally, the adsorption of the polymer on the clay minerals was higher in KC1 solutions than in NaCI, but the differences gradually disappeared when the electrolyte concentration approached saturation. The results were analyzed in terms of chaotropic (K ) or kosmotropic (Na') properties of background counter-ions and their different behaviors at the hydrated mineral-water interface. Guar gum adsorption on dolomite was related to the presence of calcium and magnesium sites on the mineral surface, and to the cis-configuration of OH groups of mannose units. Based on viscosity measurements, it was suggested that guar gum macromolecules form entanglements in NaCI solutions (and distilled water), but individual molecules exist in KC1 solutions thus creating different modes of adsorption of guar gum from concentrated NaCl and KCl solutions.

Jan 1, 2006

By André Piché

"Over the last ten years, several developments have been undertaken to conceive a machine capable of carrying out simultaneously all the mining tasks in hard rock deposits: cutting, mucking, hauling, ground support and dust control.The main advantages of continuous mining over conventional drill and blast is the elimination of the cyclical nature of the actual methods. Other advantages sought are improved stability of mine openings, higher productivity, lower costs, and a cleaner and safer mining environment. Noranda has con-tributed to these developments in a major way. As a member of HDRK, Noranda participated in the development of two mechanical continuous mining machines; the TM60 and the Wirth. Noranda also undertook a development of its own based on the utilization of electricity to break rock. This technology is called plasma blasting (PBT). The concept of plasma blasting is illustrated in Figure 1.When the operating voltage is reached (18kV), the energy is released through a high current switch (500k A) into a coaxial powercable. It is then delivered to the tip of an electrode inserted into a drill hole which is filled with an electrolyte (water). When the energy reaches the electrolyte, it is instantaneously transformed into a high temperature, high pres-sure plasma that produces a shock wave capable of breaking rock(1).After initial testing of the plasma blasting technology in the lab and in the feld, two experimental platforms were constructed. The first one, a test bench, was erected at the Noranda Technology Centre in Pointe Claire, Quebec.(2)The second one is a rock breaker prototype based on a standard diesel-powered carrier (Fig. 2). Each platform was equipped with a 300 kJ pulsed-power module.In 1993, the rock breaker prototype was used for an extensive series of tests in the field. During that campaign, over 700 oversized boulders were blasted. The results of the tests demonstrated that more durable components for PBT were needed. The test bench was then used to successfully develop and test long-lasting components (probe, switch, cable, connector) that can be adapted to industrial platforms leading to the commercialization of the technology."

Jan 1, 1996

By M. Desjardins

The Hoyle Pond underground mine, located in the Porcupine Gold Camp, east of the city of Timmins, Ontario, Canada, is the cornerstone of Goldcorp Canada Ltd?s Porcupine Gold Mines. Cut and fill, shrinkage, longhole and panel mining methods are employed to excavate the narrow gold bearing structures. In order to meet increased flow requirements of 256 m3/s at the mine, a new Fresh Air Raise (FAR) and new surface fans were commissioned in early 2005. The newly acquired fans were capable of supplying the desired volume of air within a range of 1.5 and 2.0 kPa. Upon commissioning of the surface fans the total pressure was found to be exceedingly high; far beyond the design capabilities of the new installation. Consequently only one surface fan could be operated at any given time providing about half the required volume of air. Extensive work was immediately started aimed at reducing the system resistance in order to permit operation of the two fans in parallel and achieve the required mine flows. Larger booster fans were installed in parallel at the 900 m level, a 3 m raise bore linking the 450 and 900 m levels was developed to twin the existing fresh air circuit, and the FAR from surface to the 450 m level was twinned with the original FAR. This strategy, completed in 2012, resulted in a drastic reduction in system resistance and pressures, allowing the two surface fresh air fans to be safely operated in parallel and meeting the flow requirements. This paper describes details of the engineering design work and commissioning of the modified ventilation system, successfully ensuring the long term viability of the project.

Aug 1, 2013

By Paul L. Broughton

"IntroductionThe coal deposits, all of lignite rank, of economic interest in Saskatchewan are associated with the Ravenscrag Formation (Paleocene). Several Cretaceous formations have less significant lignite accumulations (Broughton, Irvine and W'hitaker, 1974). The Swan River Group (lower Cretaceous) and Judith River Formation (upper Cretaceous) have the only coalbearing strata in the shallow subsurface of central Saskatchewan. The Swan River Group coalfield is relatively small and underlies only 15 sq km of the surface approximately 40 km south of La Ronge, Saskatchewan. An estimated 36 billion short tons are within 45 m of the surface. No reserve estimates are known to have been calculated for the coal-bearing Judith River Formation exposed at the surface in the vicinity of the South Saskatchewan River valley in west-central Saskatchewan. Although no coalfields have been delineated, lignite beds up to 1.8 m thick have been intersected in test holes. The coal-bearing upper Cretaceous and lower Tertiary strata of the northern Williston Basin extends the full width of southern Saskatchewan for 650 km, and from the United States border 120 km north to 50° latitude (Fig. 1). Only the coalfields of the Ravenscrag Formation, because of their economic interest, will be considered further. There are four major coalfields. They are, from east to west: Estevan, Willow Bunch, Wood Mountain and Shaunavon (Cypress) coalfields. Cumulative lignite seam thickness for each basin is 10 -15 m (Figs. 2 and 3). The origin of each coal basin, resource calculations, seam stratigraphy, and mining activity are discussed. Regional Setting The Williston Basin is an ellipsoidal depression in the Precambrian basement, centered in western North Dakota and marginal to the exposed craton of northern Saskatchewan and central Manitoba (Fig. 1). The sediments of the basin range from Cambrian to Pleistocene in age and have a maximum known thickness of 4614 min western North Dakota. A maximum of 3200 m is recorded in southern Saskatchewan. Most structural deformation is late Cretaceous to early Tertiary (Paleocene) in age, coinciding with the Laramide Orogeny. The pre-Laramide Williston Basin, with a depocenter near Williston, North Dakota, began developing during the middle Ordovician, or possibly earlier."

Jan 1, 1985

By Donald L. Brothers

"OUT IN BRITISH COLUMBIA, we have a legendary creature called ""The Sasquatch,"" a large ape-like creature which, according to those who claim to have seen it, somewhat resembles the Abominable Snowman of the Himalayas. Through the years, the legend bas been perpetuated by hunters and prospectors who return from remote wilderness areas with fantastic tales about hairy creatures, twice the height of an average human being, who leave 2-ft-long footprints in the soft forest floor. However, the existence of this creature bas never been proven and the attitude in British Columbia circles is that the whole thing constitutes either a great discovery or a giant hoax, and is about equally unbelievable either way.The Sasquatch, however, is not the only giant in British Columbia. If you find the Sasquatch story un-believable, you'll fi nd it just as hard to believe what is happening in the mining industry out west. We have opened four new mines so far this year (1967), another mine is expected to be brought into production before the end of the year and any mining man will tell you it's just the start of a mining boom which will continue for many years if metal prices are maintained and the federal government sees fit to discard the taxation changes pro-posed in the Carter Royal Commission Report regarding mining."

Jan 1, 1968

By D J. McDougall

Due to changes in the solid-state conditions of minerals in the rocks surrounding hydrothermal, contact meta-somatic or metamorphosed ore deposits, positive or negative thermoluminescent anomalies may be found in their vicinity. Several types of equipment which can be used for both quantitative and semi-quantitative measurements of the emission are discussed and compared. Methods of selecting, preparing and testing samples to ensure reproducible results are outlined, along with the kind of data which can be obtained from different types of equipment. The normal thermoluminescence of rock-forming min~ erals in the common rock types is noted, and variations in the solid-state conditions in the wall rocks which will cause marked increases or decreases of true thermoluminescence are outlined, as well as the thermolum-nescence-like emissions which are present in the vicinity of ore deposits. Introduction T HERMOLUMINESCENCE occurs when certain crystalline materials are heated to temperatures ranging between 180' and 400°C. The light emission can be ascribed to the release of electrons metastably trapped within the crystal lattice, with peak emissions taking place at temperatures which are more or less specific for a particular set of traps; the area under

Jan 1, 1965

By Georges Croisé, Les-Lee Thompson, Adrien Debergé

Membrane filtration systems have regained focus in recent years as an effective means of liquid-liquid separation to increase the concentration of valuable elements, recover reagents or remove impurities. ORANO Mining (formerly AREVA) investigated this cost optimization process opportunity as early as 2011 for implementation at the Trekkopje project (Namibia). The key focus was to separate and recycle bicarbonate from the uranium bearing eluate solution. The performance targets were successfully achieved at lab- and pilot scale with an ultrafiltration and nano-filtration configuration system. Early 2015, ORANO Mining further launched an investigation into the use of membranes for acid recycling at the KATCO In Situ recovery mine in Kazakhstan based on the favorable results from the original bicarbonate application. KATCO is the world leader in ISR uranium mining with an eluate processing capacity of 80 000 m3/yr. This site consists of two processing plants namely, Muyumkum and Tortkuduk, located 40 kilometers apart, both operating under acidic conditions whereas precipitation and packaging are based in Tortkuduk only. This paper serves to present the results from the integration of a nano-filtration system at the Muyumkum satellite processing plant. The project consisted of screening laboratory bench studies conducted at ORANO-CIME followed by process validation at KATCO through further bench and pilot test work. The feasibility study assessments were successfully concluded which led to the implementation at an industrial scale in Muyumkum of a nano-filtration process to reduce eluate volumes being sent to the uranium precipitation section whilst achieving effective separation of uranium from sulfuric acid. Nano-filtration technology has drawn significant attention due to the efficiency and reproducibility of the process and its moderate capital cost relative to operational savings. The reliability of the previous results is a great opportunity to reduce operative expenditures within ORANO’s next ISR mining project in Mongolia.

Jan 1, 2020

By Zhiyang Long, Ruiling Xiao

"A mine shaft is one main development method of establishing access in an underground mine. The construction technology of the mine shaft sinking is complicated and large equipment setup on surface and in the mine shaft. The paper briefly reviews a single-line operation method, parallel operation method and mixed operation method as well as the features of the one operation method with the excavation, lining and installation. The special construction technology mainly would include ground freezing methods, full diameter shaft drilling methods, caisson methods, grouting technology and concrete curtain methods as well as other methods. The paper summarizes the shaft sinking numbers and effects by the special construction methods during different periods. The paper states the shaft sinking conditions and the each created record conditions in the coal, metallurgy, non-ferrous metal, hydropower, highway, railway, nonmetallic and other industries. The paper has a prediction on the shaft sinking requirements and development tendency in the future for China.INTRODUCTIONA mine shaft is one main development method of access in an underground mine. In recent years in China the new shaft mines represent 45% of the total number of new mines. With the development of new mining area under construction and the development of deeper mines, the ratio of the mine shaft as access for underground mines will increase. The construction technology of the mine shaft engineering will be complicated, the operation site footprint will be small and the working environment will be more difficult. The mine shaft sinking operation will often be varied by the geological conditions and affected by underground water inflows, seam gas outbursts, geothermal and other natural conditions. The safe construction of the mine shaft sinking will be challenged by all these conditions. Although the mine shaft engineering will only be about 5% of the total mine roadway engineering, the mine shaft construction period often will take over 40% of the total mine construction period. With the progress of modernized mine production technology and the construction of a high production and high efficient mine, the mine transportation roadways mostly would be set in the seam and the engineered amount of the mine rock roadways reduced year by year could cause more prominent long extensions of the mine shaft construction period. Therefore, in order to speed up the construction, to shorten the mine construction period and to realize the investment benefits as early as possible, the technical level of the mine shaft sinking should firstly be improved and the construction speed of the mine shaft engineering and sinking should be speeded up, which would have important significant benefits."

Jan 1, 2019

By Anita Marks

In 2007 Copper Mountain Mining determined that there were sufficient resources to consider reopening the Similco Mine near Princeton, BC. The mill facility that had been built by Newmont Mining in 1972 was closed in 1996 and all of the process equipment removed. The mill had been built on the west side of the Similkameen River to facilitate mining of the Ingerbelle Deposit. In 1980 construction was completed on a primary crusher and cable belt to deliver ore across the Similkameen River from the Copper Mountain deposit to the Ingerbelle mill. With the decision to restart mining of the Copper Mountain deposit, the decision was made to design and build a 35,000 tpd grinding and flotation mill near the mining operations. This paper discusses the application of historical operating data for the selection of the mills for the new grinding circuit and provides an overview of the grinding circuit design.

Jan 1, 2012

By S. D. A. Hannot, H. Knapp

"High pressure grinding rolls (HPGR’s) are an energy efficient solution for comminution of industrial minerals and metal ores. The technology is successfully applied in an expanding field of applications throughout the minerals industry. HPGR’s compress and grind the particle bed in the operating gap between two counter-rotating rolls. The equipment provides a high capacity, low energy alternative for applications with conventional tertiary and quaternary crushing and grinding, with size reduction reaching from 100mm down to 25 microns product. In this process, maintaining a controlled and evenly distributed operating pressure between the rolls is very important. Due to feed segregation, the pressure distribution along the roll’s length can become uneven, resulting in a coarser product. This paper will show that the best approach to compensate and adapt for the uneven pressure is to allow the rolls to skew relative to each other. Coarser products are also caused by an inadequate pressure distribution: the much-discussed edge effect. To minimise the consequence of the edge effect, an optimised ratio for the roll length to diameter will be calculated. Furthermore, the design philosophy behind a cheek plate will be detailed. This cheek plate is used to retain the material between the rolls, reducing the edge effect while still allowing roll skew. Together these design considerations help optimise HPGR’s performance.INTRODUCTION Initially developed for the cement industry during the energy crisis in the 1980’s , high pressure grinding has been an accepted technology for many years. It has been successfully implemented throughout the minerals industry, with applications in base and precious metals, as well as industrial minerals processing. The comminution process relies mainly on size reduction through to compression and inter-particle crushing in a particle bed in the operating gap between two counter-rotating rolls. The equipment typically has a high unit capacity and low energy consumption, and is increasingly used as an alternative to conventional tertiary and quaternary crushing and grinding, in particle size ranges reaching from 100mm down to 25 microns. It can be applied to moist ores and dry material, in open circuit arrangement or in a closed circuit with dry or wet classification (screening, air classification)."

Jan 1, 2019

By J. L. Bowlby

Introduction In the following discussion, boiler-feed and mine waters will be considered from the point of view of the problems arising from the chemical nature of the mineral and gaseous impurities they contain. The theories underlying some of these problems will be reviewed for the purpose of getting a clearer concept of the problems themselves. Certain terms of a chemical nature, necessary to the discussion, will be explained on the assumption that they are not generally familiar to mining engineers. Finally, an attempt will be made to correlate theory and practice, with the abject of establishing certain limits to factors relevant to the problems, and to show that these limits are justified by practical experience. The general problems occasioned by the presence of mineral and gaseous impurities in boiler-feed and mine waters are: (1) Scale formation and corrosion in boiler systems. (2) Corrosion of mine pumps and pump fittings. These will be discussed separately. Boiler Scale Typical analyses of waters available for use in steam power-plants are given in the accompanying Table (Table I). All analytical data are expressed in grains per Imperial gallon. The bicarbonates of calcium and magnesium in the raw waters are shown as normal carbonates in the Table. Substances in the first five rows constitute the encrusting solids. All the waters listed in Table I would be classified as 'very good' in the schedule of classification for boiler waters adopted by the American Association of Railway Chemists in 1887. In spite of this classification, however, the waters contain sufficient encrusting solids to cause serious scale trouble after prolonged evaporation.

Jan 1, 1934

By Carlos Rebolledo, Nelson Parra

Arsenic is an unresolved problem in the mining industry considering the fact that most of the new copper deposits have high arsenic contents; stricter environmental restrictions for handling, transporting and processing complex materials are expected and stable abatement of arsenic is not extensively applied. In 2018 Chile produced 24.5% of the total copper from concentrates and in the future copper production in Chile is expected to increase, mainly associated with production of concentrates that will also contain more arsenic. China has set an import benchmark of maximum 0.5% for arsenic content in copper concentrates and this value is expected to be more restrictive in the future. On the first day of 2018 China banned the importation of scrap. Blending practice has been a business option, but it is not sustainable in the future, as “normal” copper concentrates become less and less clean. By the end of 2018, Chile formulated new regulations, increasing the capture of SO2 and arsenic to 95%. In order to comply with these regulations Chilean smelters had to make large invest large amounts of money. Disposing of arsenic as a stable residue is a pending issue. EcoMetales is a 100% subsidiary of Codelco and provides the mining industry with environmental solutions. It has a plant near Calama in Chile that treats flue dust from smelters, refinery effluents and acid solutions from acid plants. EcoMetales is fully committed to contributing to the solution to the arsenic problem. Currently we are developing four main projects: 1) Concentrates treatment. A PLCC project considering the treatment of 200 ktpy of copper concentrates with arsenic from the northern district of Codelco; 2) EPAS DET project considering the treatment of 700 m3/d of weak acid solution with arsenic from the of El Teniente devision of the Codelco acid plant; 3) Borras project, considering the recovery of valuable metals (Cu, Ag, Ge, Pb) from the flue dust leaching plant; 4) Tailings project, considering the recovery of metal values from tailings. The purpose of this work is to present the trends and treatment processes for arsenic handling in the copper mining industry with a focus on the scorodite process. INTRODUCTION Between 2000 and 2015 the global copper concentrates production has grown from approximately eleven to fifteen million metric tons per year. Chile produced 26.5% of the total copper from concentrates and in the future copper production in Chile is expected to increase, mainly as a result of the production of concentrates (Figure 1)

Jan 1, 2019

By J. W. Merkley, K. B. Hustwick

"The authors describe the use of a computer system for the control oj warehouse inventory at Cominco's Canadian operations. The challenge presented by the company's diverse products and various locations necessitated a practical approach to operational and manpower requirements. The utilization of modern forecasting techniques, manual intervention and exception reporting provides system flexibility. The system also provides both operational and management control to set required service goals at the lowest inventory levels for inventory management.IntroductionCominco Ltd. is a Canadian company, with international operations, the principal business of which is zinc, lead and chemical fertilizer s. Its involvement is fully integrated and range s from mineral exploration through mining, smelting, refining and by-product production to international marketing. It also embraces related services, including trade, wharfarge and power. With head office in Vancouver, it is involved, directly or through subsidiary or associated companies, in Canada and in the United States, Greenland, Europe, Australia, India and Japan.Cominco has over 12,000 employees and 26,000 shareholders, with 91% of all shares held in Canada.Cominco's Inventory Control System is one of the most extensively used computer systems employed by the company. Also, inventory control is regarded as one of the most economically successful computer applications to be undertaken by the Data Processing Services (D.P.S) Group that was responsible for the development of the Inventory Control System.The main use of automatic inventory control has been at operating plants in Western Canada and the Northwest Territories, which are separated by large distances. Each location has equipment-intensive mining and processing operations and it is essential to maintain control of parts and supplies inventories. Some of these locations are remote from urban and industrial centres and it is important to avoid the adverse effects of high personnel costs and re-training due to turnover."

Jan 1, 1982

By John F. Kearney

After World War II Canada?s fledgling iron ore mining industry developed along the ill-defined Quebec / Labrador border near what became the town of Knob Lake and later renamed Schefferville. For about twenty-five years from 1954 to 1982 Schefferville was the epicenter of Canadian iron ore mining and the foundation of the Iron Ore Company of Canada. In about 1982 it all stopped, shut down, the miners moved away leaving behind a mining camp and a ghost town that have sat idle and almost deserted for the past twenty five years. The story looks set to change with new plans to re-establish the former mining operations in the historic mining camp. This paper outlines the proposal to reactivate the direct shipping iron ore operations in the Schefferville mining camp, and specifically the properties in Labrador owned or optioned by Labrador Iron Mines Limited (?LIM?), a wholly owned subsidiary of London Stock Exchange listed Anglesey Mining plc. The Schefferville mining camp is located about 1,000 km northeast of Montreal. There are no roads connecting the area to southern Labrador or to Quebec. Access to the area is by rail from Sept Iles to Schefferville, or by air from Montreal and Sept Iles.

May 1, 2007

By Steve Custer, Chris Bennett, Patrick Garretson, Glenn Dobby, Jacques McMullen

"Barrick Gold is in the process of expanding one of its grinding circuits at the Goldstrike property as a response to both increasing ore hardness and increased ore sensitivity to finer grinding as it relates to gold recovery. The plant currently operates with two parallel grinding lines, each with a SAG mill, a pebble crusher, and a ball milling arrangement. As part of determining what additional equipment was to be required, a CEET evaluation program was conducted (CEET is an acronym for Comminution Economic Evaluation Tool). The work included: Development of a hardness ‘model’ for the ore body, as described by SAG Power Index and Bond Work Index;Site benchmarking surveys to fine tune the SAG and ball mill calibrations within CEET;Conducting CEET studies to examine the process options;Comparing CEET results to standard grinding circuit design techniques.The recommendation of the study, presently being implemented, is the installation of an additional ball mill on one of the two grinding lines. This paper reviews the sizing techniques applied, providing a CEET case study for circuit performance analysis and circuit design. OVERVIEW OF COMMINUTION AT GOLDSTRIKEOre feeding the autoclaves at Goldstrike are first processed through two parallel grinding lines. Both lines use SAG mills with cone crushing of pebbles followed by ball milling. A summary of the key circuit parameters is provided in Table 1. Line 1 primarily processes underground Meikle ore, although when no Meikle ore is available, it processes open pit Betze ore. Line 2 processes Betze ore exclusively. The Mill Line 1 P80 objective for Meikle ore is 74 microns. According to the recovery optimization analysis, a P80 of 90 microns was recommended for Betze ore. The potential however exists to perform co-mingling of both ore types and feed the higher grade Betze ore to Line 1, in which case the P80 of 74 microns would be retained."

Jan 1, 2001