Search Documents

By H. W. Kasaini, E. Bourricaudy, T. Larochelle

Rare Element Resources Inc., a U.S. based company, has developed a three-stage process for producing a +98% mixed REO powder from hard rock feedstock (-48 mesh, 2.9-4.8% REO) consisting of bastnaesite and ancylite minerals. Firstly, the whole ore is digested in chloride media at low temperature in counter-current flow mode. Secondly, the rare earths (REEs) are selectively precipitated as oxalates directly from an impure pregnant leach solution (PLS). Finally, significant amounts of free acid and water are recovered from the REE-depleted filtrate and subsequently recycled within the process. Excess heat from the oxalate calcination process is captured and reused in the plant. Due to the low leach temperature (45 ºC) and moderate acid dosage (240-297 kg/t, HCl), rare earth oxides (REOs) are preferentially leached out of fine solids leaving most of the base metals (Ba, Fe, and Al ) in the residue. Selective recovery of REEs from the PLS is achieved by mixing dilute oxalic acid (33% H2C2O4) and PLS at elevated temperature (85-95 ºC). The REEs plus thorium are precipitated as oxalates (REE2 (C2O4).xH2O) while the base metals are left behind in the barren filtrate. Multiple batch and pilot test results have confirmed that 50-80% of the oxalic acid can be recovered from the REE-depleted PLS through low-temperature crystallization (10-15 ºC). Typical leach efficiencies of critical rare earths at 45 ºC range from 85-99% (average 93%) while oxalate precipitation at high temperature increases the crystal size of RE oxalates (>450 microns, d80) thereby improving filtration. The economic benefits of this process include elimination of flotation and magnetic separation Capex and driving hydrometallurgical Opex down to $6- 7/kg, REO produced. As part of a comprehensive risk mitigation strategy, Rare Element Resources Inc has operated multiple pilot plants at SGS in Lakefield, Ontario, Canada to optimize counter-current leaching (CCL), REE oxalate precipitation (OXP), and thorium removal circuits. This paper presents pilot testing data from CCL and REE OXP circuits.

Jan 1, 2016

By CIM Mineral Resource, Mineral Reserve Committee

The CIM Mineral Exploration Best Practice Guidelines (the Exploration Guidelines) have been prepared to assist professional geoscientists and engineers to conduct consistently high-quality work in order to maintain public confidence. The Exploration Guidelines are meant to assist professional geoscientists and exploration practitioners in planning, supervising, and executing exploration programs. In Canada, there are generally two types of public resource reporting: “Disclosure”, as defined by NI 43-101, is the reporting of technical information to the public and market participants for securities legislation purposes where a Qualified Person (QP) must be involved, and reporting of exploration information for governmental agencies to support obligations under laws including the Mining Acts of each of the Provinces and Territories. The Exploration Guidelines are also relevant where the results will not be publicly reported but are intended for internal company use. While this document is intended as guidance for work conducted or supervised by geoscientists in Canada, many of the practices described herein can be adapted to mineral exploration activities in other countries. The Exploration Guidelines are not intended to inhibit original thinking, or to prevent the application of new approaches that may develop into fundamental components of successful mineral exploration programs. Rather than provide prescriptive solutions to specific issues, they include general guidelines for current professional practice and to demonstrate and defend the merits of new methods. These guidelines do not preclude individuals and companies from developing more detailed guidelines specific to their own requirements. The initial version of the Exploration Guidelines was prepared by the Canadian Institute of Mining and Metallurgy and Petroleum (CIM) Exploration Best Practices Committee and adopted by CIM Council on August 20, 2000. On January 9, 2018, CIM Council formed a new committee, the Mineral Resources and Reserves Committee (CIM MRMR Committee) with a mandate to, among other things, update the Exploration Best Practice Guidelines. The mandate for the committee was accepted by CIM Council on March 2, 2018. The new document was adopted by the CIM Council on November 23, 2018.

Nov 23, 2018

By C. J. Newman, R. J. St. Eloi, G. Macfarlane

"The Kidd Creek copper smelter has been expanded from its original design of59000 tonnes of copper per year to over 120 000 tonnes per year. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and, generally, to optimize the operation.The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to improve gas cleaning capability. The acid plant is reviewed with references to changes made to accommodate the increased S02 gas strength resulting from the higher smelting rates. IntroductionThe Kidd Creek Division of Falconbridge Limited is a base-metal mining and metallurgical complex located in Timmins, Ontario. The discovery of the original copper-zinc-silver orebody was announced in April 1964. Mining operations began in 1966 with a 9000 tonnes per day (t/d) concentrator corning on stream in November of that year. In April 1972, a 108 000 tonnes per year zinc plant was conunissioned. Over the years the facilities have been expanded, such that the concentrator now has the capacity to process 13 000 t/d of ore. To expand zinc production, the world's second installation of the Commco/Sherritt pressure leaching facility was completed in 1983 to bring total zinc production capacity to 136 000 tonnes per year. In 1973, serious planning for a smelter operation began. In early 1975, after studying both continuous smelting and flash smelting processes, a decision was made to proceed with the technology offered by Mitsubishi Metal Corporation of Japan. The Mitsubishi Continuous Smelting Process was to be used for the smelter and the Onahama No. 3 tankhouse technology for the copper refinery."

Jan 1, 1994

By E. M. Cameron

Reconnaissance radiometric and geochemical data have been obtained for an area on the western shore of Wollaston Lake that includes the Rabbit Lake uranium deposit. The study area is extensively drift cover ed. The geochemical data were obtained by analysis of center-lake sediments and surface waters for a variety of elements and other constituents. The airborne radiometric data comprise measurements of eU, eTh and K obtained with a .50,000-cc NaI (Tl) detector at a mean terrain clearance of 120 m and 5-km flight-line spacing. Uranium in lake sediments and uranium in waters are the most effective geochemical indicators of uranium mineralization; the other elements measured are not notably anomalous. A sample site density of one per 1 8 km 2 is more than adequate for identification of the mineralized area. Because many water samples contain close to or below the current analytical detection limit of 0.05 ppb U, the use of sediments is generally favoured. for broad-scale reconnaissance in the region. Uranium in these lake sediments appears to be little influenced by variations in the organic or iron and manganese content. The most effective radiometric indicator of the mineralization is the eU/eTh ratio. This parameter is less influenced by environmental variation on the ground beneath the flight line than eU alone . The eTh/K ratio is anomalous under the Athabasca Formation unconformity where, in places, the uranium mineralization is localized.

Jan 1, 1977

By G. Barr

"The Polymetallic Twin Metals Project deposits in Northern Minnesota are being developed by Twin Metals Minnesota. Amongst the flowsheet alternatives being examined at a prefeasibility study level is one involving flotation of a bulk concentrate followed by high temperature autoclaving of the concentrate using the PlatsolTM Process to solubilize all the valuable metals in the concentrate (Cu, Ni, Pt, Pd and Au). Autoclave operating conditions have been established in which recoveries of all the pay metals are in the 92 to 99% range, and the autoclave residence time has been reduced to an hour. The stability of the precious metals in solution after autoclaving has been assessed, as well as the impact of internally recycling process liquors to the feed to the autoclave.INTRODUCTIONPlatinum group metals (PGMs; platinum, palladium, rhodium, ruthenium, iridium and osmium) are traditionally recovered from their ores by production of a high-grade concentrate by flotation and/or gravity concentration followed by smelting of the concentrate. Concentrates are smelted to remove nonsulphide minerals and converted to remove iron and sulphur. The resulting high PGM grade matte is processed hydrometallurgically to leach the base metals, leaving a residue with a very high grade (20-40%) PGM concentrate for final refining to individual PGMs. Due to the complexity of this process and its high capital cost, this process can only be applied economically to high grade PGM ores. Lower grade PGM concentrates might be accepted as copper and nickel concentrates but may not yield attractive payment terms for the PGMs. The mineralized Duluth Gabbro region of Minnesota hosts several low grade base and PGM deposits and Twin Metals Minnesota is working to develop the Twin Metals Project deposits. Earlier studies at both pre-feasibility and feasibility level, by other mining companies, have failed to yield an economically viable project based on the traditional process. It is possible to produce a saleable copper concentrate from these ores, but economic recovery of nickel and PGMs into saleable concentrates proved elusive.In the late 1990’s and early 2000’s the Platsol™ process was developed at SGS in Lakefield, Ontario (at the time Lakefield Research Limited) for the NorthMet deposit (also within the Duluth Gabbro) owned by PolyMet Mining. The process developed was a high temperature chloride-assisted pressure oxidation process capable of dissolving simultaneously the base metals (Cu, Ni, Co, Zn), gold and the PGMs."

Jan 1, 2012

By Atul Bhatnagar, M. P. Sinha, Md Zahid Ahmad, Pallav Garg, Sanjay Kumar Singh, Shashi Ranjan, An Ecolab Company Nalco Water

"Froth Flotation is undoubtedly one of the most critical processes in coking coal washing plants. This work was carried out at Bhelatand Coal Preparation Plant of Tata Steel was with an objective of cost optimization in fine coal processing. The sources of raw coal for the plant include coal from underground mines of Jharia coalfield and procured open-cast raw coal. Coal from different sources vary in quality and possess different floatability characteristics.Synthetic collector is being used in plant as a flotation reagent. An alternate collector with new chemistry was developed for reducing total treatment cost without compromising product yield and quality. A series of laboratory tests were conducted to assess the performance of various sources of raw coal and plant scale trial was started. At first, the new generation coal collector was entirely substituted with the existing collector in the laboratory scale. However the plant scale trial data was not in accordance with laboratory results and indicated inferior flotation performanceThe issue was studied and data based conclusions were drawn that the new generation collector aids faster and uncontrollable kinetics. A decision was taken for co-dosing of the synthetic and new collector for the second phase of the trial. A detailed laboratory analysis was done again and few dosing ratios that predicted optimum results were selected for plant trial. The dosing ratio was optimised as per flotation yield and product ashes during the plant trial. The results showed significant improvement from the first phase and optimum dosing rates were decided based on plant observations and data collection. The influence of various process indicators including water quality, feed and product ashes and process yield was studied during all the trials and promising results were established. The co-dosing of both the collectors conferred cost advantage and enabled to achieve superior performance."

Jan 1, 2016

By William F. Caley, A. MacKinnon, P. W. Kingston

"The purpose of this paper is to identify a number of currently available opportunities for exploration and/or mine development in the industrial minerals field in southeastern Ontario. The paper is not intended as a complete review of the industrial minerals industry in southeastern Ontario, but highlights what are seen by the authors as areas where there are immediate opportunities for investment and growth.Traditional exploration targets in the Grenville Supergroup in southeastern Ontario have been vein-hosted gold deposits, industrial minerals, and base metals. In recent years, emphasis has increasingly shifted to industrial minerals, in response to changing technologies in the minerals-consuming manufacturing industries, and to an increasing awareness of the industrial mineral potential in this area.This paper examines the resurgence of interest in exploring for and developing a wide variety of industrial minerals, and it examines the work the Ontario Ministry of Northern Development and Mines has done under the current Canada-Ontario Mineral Development Agreement. Specific development opportunities are identified in various commodity areas. Use oj the industrial minerals wollastonite and nepheline as substitutes for fluorspar in the formulation of synthetic steelmaking slags is also discussed."

Jan 1, 1990

By J. D. Clucas, N. Verbaan, T. Grammatikopoulos, D. B. Dreisinger, C. Forstner, M. Aghamirian

"Search Minerals is currently exploring the Port Hope Simpson (PHS) Rare Earth Element District in southeastern Labrador, Canada. The Foxtrot Rare Earth Element (REE) Project in the PHS District has a 43-101 resource estimate consisting of 3,410,000 tonnes of Indicated Mineral Resources and 5,850,000 tonnes of Inferred Mineral Resources. The indicated and inferred resources contain 1.07% and 0.98% total rare earth element oxide (including yttrium), respectively. The dysprosium and neodymium grades are particularly attractive at 218 ppm Dy2O3 and 1687 ppm Nd2O3 for the indicated resources and 208 ppm Dy2O3 and 1494 ppm Nd2O3 for the inferred resources. The mineralization remains open along strike and at depth and is only one of a number of attractive exploration targets in the Port Hope Simpson area. The REE minerals fergusonite and allanite are present. The ore can be beneficiated by gravity, magnetic separation and flotation to a recovery of +80% for the individual REE. Acid bake and water leaching may be used to extract REE into solution for subsequent purification and recovery. The extraction range for single stage leach tests were 91-96% for Nd, 84-87% for Tm and 92-94 % for Dy with modest acid consumptions. INTRODUCTIONSearch Minerals Inc. (Search) is exploring the 100% owned Port Hope - Simpson District in Labrador, Canada for rare earth elements (REE). This District is approximately 135 km by 12 km in size, and is highly prospective for heavy and light rare earth elements. A total of 11 REE prospects have been discovered in the District to date, including the Foxtrot. In addition, Search is exploring in the 100% owned Henley Harbour region and has joint ventures with Quest Rare Minerals in the Strange Lake region, and with Great Western Minerals Group in the Red Wine complex, all in Labrador. These exploration locations are illustrated in the Figure 1. The focus of this paper is the investigation of the mineralogy and processing of Foxtrot REE materials. The Foxtrot resource falls within the claims held by Search in the Port Hope Simpson REE District. The infrastructure available at Foxtrot is excellent with a deep water port, air strip and road and power infrastructure at Port Hope Simpson. Over $7 Million has been spent to date on exploration and development of the District. The Foxtrot has been explored using prospecting geochemical methods, geophysics (airborne and ground), channel sampling of surface outcrops, mapping and three phases of drilling (18,934 m total)."

Jan 1, 2012

By Jeanne B. Percival, Paul Ramaekers, Charles W. Jefferson, Pat A. Hunt, Eric G. Potter, Katherine E. Venance, William Davis, Sean A. Bosman

"A 10-cm thick clay-rich layer near the top of the Manitou Falls Formation of the Athabasca Group is unusual in its breccia texture, alteration, and detrital mineral composition relative to the adjacent overlying and underlying sedimentary beds. This layer is composed of angular quartz grains set in an illite >> kaolinite + dickite matrix. Deformed clay-rich fragments within the layer have very similar mineral assemblages. The presence of euhedral accessory minerals including Ti-oxides and aluminophosphatesulphate minerals points to a diagenetic/hydrothermal origin. The presence of individual grains of Kfeldspar and amphibole is unusual relative to the typical Athabasca quartz arenite; originally, these minerals were probably included in detrital quartz and subsequently liberated during fracturing. The textures and alteration characteristics suggest that this layer is a hydraulically-fractured unit, which has experienced hydrothermal fluid alteration - a possible pathway distally related to uranium mineralization Une couche argileuse de 10 cm d’epaisseur pres du sommet de la Formation de Manitou Falls du Groupe d'Athabasca est remarquable par sa texture brechique, son alteration et la composition de ses mineraux detritiques qui different de ceux des couches sedimentaires sus- et sous-jacente. Cette couche est composee de grains de quartz angulaires dans une matrice composee d’illite >> kaolinite + dickite. Des fragments deformes riches en argile dans cette couche presentent des assemblages mineraux tres similaires. La presence de mineraux accessoires idiomorphes dont des oxydes de titane et des aluminophosphates-sulphates suggere que ces derniers ont une origine diagenetique / hydrothermale. La presence de grains de feldspath-K et d'amphibole est inhabituelle comparativement aux arenites quartziques typiques de l’Athabasca; initialement, ces mineraux constituaient probablement des inclusions dans le quartz detritique qui ont ete subsequemment liberees pendant la fracturation. Les textures et les caracteristiques de l'alteration suggerent que cette unite a subi une fracturation hydraulique et a ete alteree par un fluide hydrothermal - possiblement en lien avec les effets distaux de mise en place de la mineralisation en l'uranium."

Jan 1, 2013

By W. P. Campbell

THE investigation herein described had its beginning in the chemical laboratory of the Department of the Interior, Calgary. After the transfer of the natural resources to the Province of Alberta in 1930, the laboratory was closed and the investigation discontinued, but in 1933, with the permission of the Director of the Mines Branch, the work was again taken up and brought to completion. OBJECT OF THE INVESTIGATION The object of the investigation as originally planned may be stated as follows : (1) To determine the chemical composition of the limestone formation underlying Turner Valley gas field. (2) To identify 'beds' in the limestone, if such existed, with definitecharacteristics which would mark them from immediately overlying and underlying measures. (3) To relate information acquired on the composition of the limestone to the occurrence of oil and gas in the particular section examined. Definite information was lacking as to the exact chemical composition of the limestone and of its variations in composition at various depths. The formation was generally referred to in the field as the 'dolomitic' limestone, but the depth to which the dolomitized zone extended and the degree to which the limestone generally had become dolomitized were not known. Jn the drilling and logging of wells, the recognition of suitable 'markers' in the various formations is a matter of some importance. Markers are generally relatively small but widespread members of a formation, which have some characteristic property, of colour, composition, or form, by which they may be identified, and with them, consequently, the formation of which they form a part. In the formations above the limestone in Turner Valley, a number of well defined and easily recognized markers are known to geologists, drillers, and others interested in the field. Many of these markers Hand out in sharp contrast to adjoining measures and are therefore easily recognized; in others, the contrast is less sharp, with consequent difficulty in identification.

Jan 1, 1937

By A. G. B. Hayes, C. L. Renzoni

"AbstractThis paper provides a rough outline of economic expectations for the near future and then goes on to discuss their effect on the expected demand for metals, using zinc, copper, nickel and aluminum as detailed examples.IntroductionMINING, as you are all painfully aware, is a cyclical business. We believe that it will remain so as long as there are economic cycles.The fortunes of the industry are tied to those sectors of the economy where decisions can be postponed until more favourable times: automobiles, housing, appliances, inventory building and capital spending. Over the past two years, while U.S. GNP fell by 3.8%, automobile production declined by 31 %, from 9.7 million units in 1973 to 6.7 million in 1975. Housing starts plummeted some 43% from 2.1 million units in 1973 to 1.2 million in 1975. Little wonder that U.S. copper consumption fell by 37% and zinc consumption by 38% over the same period.With the rest of the world's economies moving in unison with that of the United States, it is also not surprising that times have been tough for mining.Arthur Burns, chairman of the U.S. Federal Reserve, contends that each recession sows the seeds of its own recovery. The worse the recession, the better the subsequent recovery. If this is true, then the lot of the mining industry should improve significantly over the next two to three years."

Jan 1, 1977

By C. H. Buck, A. J. Taylor

"In 2015 Vale’s Clarabelle Mill began the process change to enable a higher degree of Cu separation. The flowsheet modification was part of a complete divisional flowsheet change being implemented in Vale’s Sudbury Operations. This paper will centre on some of the Operational Readiness (OR) work, culminating in the commissioning of the circuit in March 2017. The emphasis will be on the implementation of an integrated test plan to prepare for the process flow change through the mill.BackgroundClarabelle Mill (CBM) began making a saleable Cu concentrate in 2006 with the installation of the Cu separation circuit. Typical separation rate was 35-40% of Cu in feed reporting to Cu concentrate based on a target Ni concentrate Cu:Ni target of 0.7-0.8. The remainder of the recovered Cu (55-60%) reported to Ni concentrate and was smelted through the Copper Cliff Smelter.In 2013 a capital project, Surface Facility Upgrade (SFU), was implemented to focus on matching the surface plants capacities with the future mine plan to maximize revenues. This was to be achieved by redistributing the metal flow, specifically Cu, through CBM to increase metal unit content through the Smelter. The amount of redistribution of Cu was determined to be based on maintaining a stable Cu to Ni ratio (Cu:Ni) in the Ni concentrate.The change in Cu:Ni ratio in the Ni concentrate would affect the Sudbury divisional flowsheet, and required process changes across the all of the surface plants. The detail that surrounds the flowsheet changes as a whole will not be discussed, but the outcome of the decisions plays a large role in the operational readiness interactions between the mill, its suppliers and its downstream customers."

Jan 1, 2018

By Paul J. Bourassa

Alin de pourvoir aux besoins d'hébergement des quel¬ques 1600 employes qui travailleront dans toutes les spheres opérationnelles de l'exploitation du gisement du Mont-Wright, ainsi que de leurs families, Quebec Cartier a dû, avec l'aide de conseillers reconnus, et /a participation de ses employes résidant a Gagnon, étudier tour les nouveaux établissements résidentiels nordiques des dernières années tout au Canada qui dans lee pays scandinaves afin d'être en position de coneepter une agglomeration moderne répondant a toes les besoins de see future résidants. Les pre¬miers residants ont pu passer Noel 1972, et maintenant les logements prévus et construits sont °coupes a 92%.

Jan 1, 1977

Éléonore Project Highlights Éléonoreis a multi-million ounce, high grade gold discovery in Québec Currently at the advanced exploration and engineering studies stage Excellent potential for expansion Underground mine with potential for small open pit Excellent infrastructure including road and high quality/low cost electricity within 70 km Les Mines Opinaca Ltée, a 100% subsidiary company of Goldcorp, was created to manage and operate the Éléonore Project

May 1, 2007

By Y. Yhang, D. C. Sego

ABSTRACT This paper evaluates the potential of freeze-thaw dewatering using Albian mature fine tailings (MFT). Freezing tests were first performed to study the effect of freezing rate on dewatering efficiency. Lower freezing rate resulted in higher thawed solids content and shear strength. Subsequently, large strain consolidation tests were conducted to investigate consolidation behaviour and how it is affected by freeze-thaw. The consolidation behaviour was presented in terms of effective stress versus void ratio and permeability versus void ratio. The results can be used to predict the field behaviour of Albian MFT and optimize the application of freeze-thaw for MFT dewatering.

Jan 1, 2014

By T. W. Wloder

During recent studies concerning the effects that various surface treatments, surface imperfections, locked-in residual stresses and metallurgical and geometrical notches have upon the mechanical behaviour of metals and, in particular, upon their tension-bending characteristics under impact loads, it became apparent that specially developed methods and samples would be of great assistance in determining the desired data. This paper describes and discusses a number of different types of double-notched tension-bending impact samples which have been considered and examined for this purpose. The types most suitable for exploratory investigations are proposed for application in the study of the _behaviour of metals, their welds, and, in particular, their surfaces, when subjected to various notch-severities, surface imperfections, strain rates, temperatures, and constrained states of stress (i.e. the relations of the three principal stresses). It is expected that the proposed double-notched tension-bending samples and the proposed test methods will also contribute toward further understanding of the cold brittle behaviour and the notch-sensitivities of metals. The possibilities of introducing the so-called impact notch-sensitivity index and relative impact notch sensitivity of metals are discussed. Data obtained on double-

Jan 1, 1961

By P. Lafleur

All indications point to a growing market for thermal coal in Japan as part of the country's current energy policy formulation process. The Ministry of International Trade and Industry forecasts imports of 16 million tons a year in 1985 and 40 million tons in 1990-a twenty-fold and forty-fold increase over the present level. This potential reflects Japan's over-all serious and increasing concern for security of energy supplies and its resultant need to seek alternative sources. Nuclear power will be the main alternative source, but, because it is expected that its development will be slow, imported thermal coal will assume greater importance. Canada, with large resources of all types of coal, could fill a portion of this market. Thermal coal could come from specific thermal coal developments or from metallurgical coal mines, which usually produce a certain amount of coal not amenable to coking, but suitable for power purposes. However, penetration of this Japanese market by Canadian thermal coal will depend on the resolution of a number of problems. On the demand side, siting, environmental aspects, the need for a coal unloading and trans-shipment centre, and the added cost of installing coal-fired stations could be major constraints. Although Canada has ample high-quality resources, any new development tied to the Japanese market will require improvement in prices to cover the high costs associated with transportation, the construction of new mines and the provision of new infrastructure.

Jan 1, 1979

By Neil Campbell

Abstract Following discovery on the Giant property of very promising gold deposits, some of which terminate against the steeply-dipping West Bay fault, a geological study was initiated co locate possible faulted extensions of the ore. Geological mapping revealed that the ore and the shear zones to which the ore is confined are older than the fault and therefore subject co displacement by it. It also disclosed several diabase dykes which seem co provide the best basis for determining the fault movement. After applying various techniques co determine their strikes and dips, the dykes were used as structural markers and it was estimated that, subject co certain possible errors, the movement on the fault was 16,140 feet (3.06 miles) south and 1,570 feet (0.297 miles) down on the west side relative co the ease. Evidence supporting this conclusion was obtained when subsequent deep diamond-drill holes intended to test the hypothesis cut an ore-bearing major shear zone which, so far as can be determined, is nearly identical with its present correlative on the Giant property. Introduction The fault under consideration follows a northerly trend past the west side of the original settlement of Yellowknife, which is situated 600 miles north of Edmonton and 400 miles from the Northern Alberta Railway terminus at Waterways, Alberta. The mining properties chiefly concerned include the southern part of the Giant claims, on the east side of the fault, and the Con-Rycon-Demelt claims, on the west side, 3Y2 miles to the south. Geological data were also obtained from the eastern part of the A. Y.E. property, which lies south of the Giant claims, and from the Negus, Meg, Yellorex, and Kam properties, which are south and southeast of the Con-Rycon-Demelt claims. Recognition of the major faults in the Yellowknife Bay area, including the West Bay fault which appears to be the greatest, resulted from the work of Dr. A. W. Jolliffe (McGill University, formerly of the Geological Survey of Canada) in 1935 and subsequent years. It has been stated with little exaggeration that these faults rank with the largest known steeply-dipping dislocations of the earth's crust. In the winter of 1939, a mineralized shear zone named the Creek Vein was found on the Giant property. It was noticed that the space relationship between the new shear zone and a body of quartz-feldspar porphyry is roughly the same as that between the Con C-4 shear zone and a body of acidic flows lying north of the Con property. Coupling this relation with the assumption that the movement along the fault is dominantly horizontal, it was postulated that the Giant shear zone represented the faulted extension of the Con C-4 shear.

Jan 1, 1947

By G. W. Clark

"The mining of the ore bodies at Rabbit Lake has in the past been by the open pit method. This method is presently being used to develop the B-zone and will continue into the future with the development of two smaller ore bodies, the A-zone and D-zone. The Eagle Point orebody will be developed by an underground method which will provide production and employment into the next century.The ore bodies at B-zone, A-zone and D-zone are unique in that they are located under Wollaston Lake. To permit mining by the open pit method a steel-celled dyke has been constructed around the north end of the B-zone. This same dyking method will be used for the A -zone and D-zone. INTRODUCTIONMine development at Rabbit Lake commenced in 1970when a detailed engineering feasibility study established the viability of the Rabbit Lake deposit. In 1972 construction of the mill and camp site began. Construction materials were seasonally hauled to the site over a winter road until November 1973when the government of Saskatchewan completed an all-weather road to within six miles of the operation.In October 1974, stripping of the Rabbit Lake open pit began with the removal of overburden and lake bottom sediments from the previously drained Rabbit Lake. The first ore was processed by the mill in June 1975and by October the mill was producing three million pounds per year. The design capacity of five million pounds annually was first achieved in 1977 and maintained until 1981, when lower ore grades resulted in lower production rates .It was clear when mining at Rabbit Lake began that, without additional reserves, the Rabbit Lake operation had a life of less than 10 years. Exploration, therefore, continued in the immediate area in an attempt to discover additional uranium mineralization."

Jan 1, 1989

By S. Koski

The Cerro Verde copper-molybdenum porphyry mine, majority owned and operated by Freeport- McMoRan Copper & Gold, is located 30 km southwest of Arequipa Peru. The concentrator, which produces copper and molybdenum concentrates, started operating in late 2006 with a 108,000 tpd design capacity, processing primary sulfide ore (mainly chalcopyrite and molybdenite). Plant capacity was recently increased to 120,000 tpd. The comminution circuit consists of one 60? x 113" primary crusher, four MP-1000 secondary crushers in closed circuit with dry screens, four 2.4m x 1.6m High Pressure Grinding Rolls (HPGRs) in closed circuit with wet screens, and four 7.3m x 11m gearless ball mills in closed circuit with cyclones. The HPGR circuit is fed by the Secondary Crushing circuit product at a T80 of 35 millimeters, and the HPGR circuit product feeds the Ball Mill circuit at a T80 of 3000 microns. This paper describes operating experiences with HPGRs during these first four years highlighting improvements in operating practices and presentation of data regarding operational efficiencies, also discussed are the primary benefits provided by HPGRs such as production of micro fractured particles, reduced ore Bond Work Index, and reduced power consumption. Cerro Verde represents the first installation of HPGRs in both the copper industry and large scale hard rock mining.

Jan 1, 2012