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By D. W. McDonald, L. M. Heaman, R. A. Creaser, T. Davies, T. Chacko, A. Simonetti

"The Three Bluffs gold deposit is located in the Committee Bay greenstone belt, which forms part of the Rae domain of the western Churchill province, Nunavut, Canada. Gold mineralization is hosted by iron formation of the Neoarchean volcanosedimentary Prince Albert Group, and is associated with silicification (quartz veining) and sulfidation of magnetite and other Fe-rich minerals. Conventional U-Pb zircon dating of a conformable dacite unit within the volcanosedimentary host-rock sequence and a crosscutting diorite intrusion confirm a ~2.7 Ga age for deposition of the supracrustal package. U-Pb monazite dates and Pb isotopic analyses of sulfides were obtained by laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS). A subset of U-Pb monazite (1813.8 ± 8.7 Ma) and Re-Os arsenopyrite (1822 ± 21 Ma) dates, combined with a Pb-Pb secondary errorchron age for pyrite and arsenopyrite (1829 ± 77 Ma), suggest that gold mineralization associated with sulfidation of the iron formation occurred at ~1815 Ma, prior to high-grade (upper amphibolite facies) tectonometamorphism in the Three Bluffs area (D2TB/(M2TB). An ~1815 Ma age for deposit formation is broadly consistent with evidence from elsewhere in the western Churchill province and to the southwest in Manitoba and Saskatchewan for a late Trans-Hudson (1.9-1.8 Ga) gold mineralizing event. The majority of U-Pb monazite ages form a second population at 1780.6 ± 4.2 Ma, similar to the age of the majority of Re-Os arsenopyrite analyses (1763 ± 11 Ma). These dates are thought to reflect the timing of peak M2TB metamorphism. 40Ar/39Ar dating of amphibole, biotite, and muscovite yielded plateau ages ranging from 1723.8 ± 9.0 Ma to 1710 ± 17 Ma, which are interpreted to record the timing of postpeak metamorphic cooling to below the respective closure temperatures for Ar diffusion in these minerals. Le gîte aurifère de Three Bluffs est situé dans la ceinture de roches vertes de Committee Bay, laquelle appartient au domaine de Rae dans l’ouest de la province de Churchill, au Nunavut, Canada. La minéralisation aurifère est encaissée par des formations de fer d’âge Néoarchéen appartenant aux roches volcanosédimentaire du Groupe de Prince Albert; la minéralisation est associée à de la silicification (veines de quartz) ainsi qu’à la sulfidation de la magnétite et d’autre minéraux riches en Fe.Les résultats de la géochronologie U-Pb conventionnelle sur une unité de dacite concordante au sein de la séquence volcanosédimentaire ainsi que d’une intrusion de diorite qui les recoupe indiquent que ces roches supracrustales ont un âge de ~2.7 Ga. Les âges U-Pb de la monazite ainsi que les analyses des isotopes du plomb des sulfures ont été obtenus par ablation laser (LA-MC-ICP-MS). Certains des âges U-Pb obtenus à partir de la monazite (1813.8 ± 8.7 Ma) et des âges Re-Os retournés par l’arsénopyrite (1822 ± 21 Ma), en association avec l’âge indiqué par une isochrone à données dispersées « errochron » secondaire Pb-Pb pour la pyrite et l’arsénopyrite (1829 ± 77 Ma), suggèrent que la minéralisation aurifère associée à la sulfidation de la formation de fer s’est formée vers ~1815 Ma, avant que l’événement tectonométamorphique (D2TB/(M2TB) de niveau élevé (faciès des amphibolites supérieures) affecte le secteur de Three Bluffs. Un âge de mise en place de ~1815 Ma pour ce gîte est compatible avec les données en provenance de l’ouest de la province de Churchill ainsi que plus au sud-ouest au Manitoba et en Saskatchewan qui indiquent la mise en place de minéralisations aurifères à la fin de l’orogénèse Trans-Hudsonienne (1.9-1.8 Ga).La majorité des âges U-Pb de la monazite constituent une seconde population formée à 1780.6 ± 4.2 Ma, ce qui est similaireLà l’âge obtenu pour la plupart des analyses Re-Os sur l’arsénopyrite (1763 ± 11 Ma). Ces âges reflètent probablement l’atteinte du pic métamorphique M2TB.La géochronologie 40Ar/39Ar de l’amphibole, de la bio"

Jan 1, 2009

By Robert Cluff

The Campo Morado precious-metal-bearing, volcanogenic massive sulphide district occurs in a Lower Cretaceous felsic volcanic sequence in a northerly trending belt in the Guerrero Terrane in northeastern Guerrero, Mexico. During upper Cretaceous to Early Tertiary greenschist-facies regional metamorphism, the rocks were deformed strongly into a northeast-verging fold-and-thrust belt. The deposits belong to a low-sulfidation, volcanogenic massive sulphide system formed in a subaqueous environment, and are of the siliciclastic type. Most are on the flanks of felsic domes or in adjacent basins and many are associated with heterolithic volcaniclastic rocks. The Reforma and possibly the El Rey massive sulphide deposits are interpreted to be overturned, and the Naranjo, El Largo, and Estrella de Oro deposits and the El Profundo occurrence to the south are upright. The G9 deposit and the La Lucha and San Rafael occurrences are in an over-thrust plate further to the southwest. In several of the deposits, zinc, lead, silver, and gold are concentrated near the stratigraphic top, and copper is concentrated near the stratigraphic base; copper also is concentrated in replacement bodies near the top of some domes. Major minerals are pyrite, quartz, ankerite, sphalerite, chalcopyrite, and galena. Gold and silver occur in argentian gold, and silver also occurs in tennantite/freibergite and galena. Underlying stockwork zones contain disseminated and vein quartz, pyrite, chlorite, and ankerite, with locally abundant chalcopyrite and/or sphalerite. Exploration since 2004 has enlarged greatly the El Largo and the high-grade G-9 deposits, and slightly enlarged the El Rey deposit. The cumulative in situ massive sulphides for the Reforma, Naranjo, El Rey, El Largo, and G9 deposits exceed 45 Mt.

May 1, 2006

By Tapiwa Chenje, Victor Olivas, Peter Radziszewski

"Ore breakage and grinding media wear have always been considered and determined separately in laboratory tests. However the two processes are linked with the ore broken down in any comminution device being responsible for the majority of the steel wear experienced. The Comminution Dynamics Laboratory (CDLab) successfully developed a test methodology that can more accurately predict grinding media wear in tumbling mills than the Bond Abrasion test. This paper looks at the possible application of the abrasive wear methodology to determine breakage parameters of the same ore used in the abrasion test. Results indicate that breakage parameters comparable to t10 can be determined using the Steel Wheel Abrasion Test (SWAT), while using significantly less ore than standard breakage tests.BACKGROUNDThe Rubber Wheel Abrasion Test (RWAT) is an internationally accepted and widely used method for determining the abrasion wear behavior of materials. The abrasion wheel test was developed to primarily utilize a steel wheel (Brinell, 1921). Haworth (1949) criticized using of the steel wheel by arguing that increasing the contact area size in the steel wheel test causes a change in the wear rate with time. He suggested that the use of a rubber wheel instead eliminates this problem, leading to the adoption of the RWAT which was standardized in ASTM G65 (2004).Radziszewski (2002), however, found that the use of the Steel Wheel Abrasion Test (SWAT) was more applicable for wear testing in the mining industry for two critical reasons. Firstly, the major cause of wear in a ball mill, the most frequently used comminution device, is ball-ore-ball contact and also ball-ore-liner which both are metal-ore-metal contact. Therefore, using the steel wheel has the advantage of providing a similar abrasive environment to the one that takes place in a real ball mill. Secondly, the SWAT creates the potential of running experiments at much higher force regimes that are closer to what happens in actual mills, unlike the RWAT which is a low stress test."

Jan 1, 2011

By P. Toscano

The objective of this investigation was to determine how the losses of nickel, copper and cobalt in fayalite slags could be controlled for nickel mattes with iron contents below 5 wt%. Laboratory-converting and slag-cleaning experiments were carried out at 1250°C. Several variables were investigated during and after converting to help minimize the amount of nickel and cobalt that reports to the slag. The variables used were oxygen concentration in the blast, coke breeze addition and nitrogen injection stirring. In all the experiments, slag and matte co-existed. Coke additions during converting have little effect on the losses of nickel, copper and cobalt. In fact, coke additions retard the converting process by consuming some of the oxygen injected. On the other hand, coke additions and nitrogen injection applied after converting was completed resulted in decreased slag losses.

Jan 1, 2004

By P. Toscano, T. A. Utigard

"The objective of this investigation was to determine how the losses of nickel, copper and cobalt in fayalite slags could be controlled for nickel mattes with iron contents below 5 wt%. Laboratory-converting and slag-cleaning experiments were carried out at 1250°C.Several variables were investigated during and after converting to help minimize the amount of nickel and cobalt that reports to the slag. The variables used were oxygen concentration in the blast, coke breeze addition and nitrogen injection stirring. In all the experiments, slag and matte co-existed.Coke additions during converting have little effect on the losses of nickel, copper and cobalt. In fact, coke additions retard the converting process by consuming some of the oxygen injected. On the other hand, coke additions and nitrogen injection applied after converting was completed resulted in decreased slag losses."

Jan 1, 2004

By J. H. Archibald

"IntroductionShot-saws are used for sawing rock throughout the dimension stone industry especially in granite quarry mills. Shot-saws, as currently designed, have an inherent wear problem which leads to slow cutting rates and repetitive blade changes which consumes much time. Because the saw blades are made from steel the abrasive shot used with them is limited to a certain hardness which effects the over-all efficiency of the sawing operation. Suggestions are made toward optimization of blade design and the sawing process. Blade DesignA common steel blade design is shown in Figure I. Note the perforations in the blade. These perforations or holes in the blade serve two or three purposes. The most obvious reason is to allow the abrasive shot a pocket in which to collect at the bottom of the blade, so that it can be distributed from these pockets into the cutting zone underneath the blade. The abrasive is fed to the saw in a slurry and usually comes in from the top. The blade must then cut a kerf wider than itself in order that the abrasive grains have a path leading from the top of the blade, down along its sides, and finally reaching the pockets and cutting zones. This circuitous path followed by the abrasive leads to side wear on the blades and high friction which can lead to blade buckling in severe cases. However, the fluidized path of the abrasives down the sides of the blade serves another purpose which is a positive gain if conditions are properly controlled. The abrasive slurry interacts with the perforations of the blade, the blade itself and the rock. This gap and the perforations in the blade, which are fluid filled, are sites of constant shearing motion. Eddy currents form in these gaps and pockets which tend to stabilize the blade by setting up balanced hydrodynamic forces which otherwise might not form in a non-perforated blade. A stable blade produces a more uniform cut in the rock. The third and final reason for the perforations are to allow the blade to wear in such a fashion that new pockets are always being formed and, consequently, new cutting surfaces between these pockets are also formed."

Jan 1, 1993

By Alain Dorval

"''Purification of marine sands from Les Iles-de-la-Madeleine''This paper presents the results of the work that has been done at CRM pilot plant for «Les Silices du Golfe Inc.». Essentially the purpose of this piloting was to demonstrate, on a semi-industrial scale, the process of purification of marine sands from Les Iles-de-la-Madeleine; that had been developed by CRM Process Development Service. This purification is necessary to produce silica suitable for the glass sand and the foundry sand markets.Introduction«Les Silices du Golfe Inc.» is a company who intends to dredge marine sands around the «Les Iles-de-la-Madeleine» coasts. The material will be transported to Gaspesia where electricity, water supply, and a convenient site is available to treat it. A high purity silica intended for glass sand and foundry sand markets will be produced. The objectives of this purification process are to remove organics, calcium, feldspars and iron.Material ReceivedCRM received 50 tons of sand with Si02 varying between 80,6 and 99,3 % (see Figure.1). The highest variations in impurities were the calcium and lost on ignition. We notice direct relation between% SiO2, % CaO and % L.O.I. as you can see on the following Figures 2, 3 and 4."

Jan 1, 1994

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 Ian Thomson

The Social License to Operate ? We are operating in an era where social license in the resource industry is as important ? if not more important ? than mineral potential ? Concept proposed by Placer Dome executive Jim Cooney in 1997 as essential requirement for the future survival of the mining industry ? ?You don?t get your social license by going to a government ministry and making an application or simply paying a fee? It requires far more than money to truly become part of the communities in which you operate.? Pierre Lassonde, President of Newmont Mining Corporation (2003). What it is ?Granted by the local community ? Intangible, informal, non-permanent ? Has to be earned and then maintained ? Defined as ? Ongoing Acceptance (a lower level) ? Ongoing Approval (a higher level) ? Expression of the quality of the ?relationship?

Aug 1, 2013

By M. Pearson, J. Irvine, L. Mercer, P. Lauzon

Severe service ball valve performance has a direct impact on the mechanical availability of high pressure oxidation and leach plants. The primary function of these valves is to isolate the autoclave for maintenance. Valve failure has historically contributed significantly to the maintenance downtime of these process plants. An understanding of the root causes of valve failures is the first step in increasing the reliability of the severe service ball valves. A rigorous failure analysis practice has been developed by Hatch for investigating refractory failures in furnaces and kilns based on Kepner-Tregoe methodology. The method has also been modified for valve failure analysis. From a root-cause failure tree analysis of each of the valve components, a list of all potential valve failure mechanisms was developed for ranking and evaluation, along with recommendations for further valve development. The purpose of this paper is to present the reader with the modified Kepner-Tregoe method and examples of this analysis.

Jan 1, 2004

By C. A. Horne

"The transportation of mineral solids in the form of slurry is a subject most of us are associated with and, in fact, live with on a daily basis. The design parameters of slurry systems and most important the prime movers or cent¬rifugal pumps, are frequent and often controversial subjects due to the lack of practical guidelines which, if known and followed, can increase both reli¬ability and service life of the equipment.In this talk, emphasis has been placed on the practical side or rule-of-thumb approach to applications which, in turn, has been related to successful field results. The theoretical content and complex design criteria associated with actual equipment design has consequently been held to a minimum in the following discussions.I. BASIC SLURRY PUMP DESIGN CONSIDERATIONSFirst, to better understand how a centrifugal pump performs work, a basic description of the operating principles are in order.A. Operation In a pump, mechanical energy is transformed into pressure energyby virtue of the centrifugal force exerted by the rotating impeller. The liquid is discharged by centrifugal force at a velocity required to generate a given head and the volute collects the liquid so useful work can be done by the conversion of kinetic energy to pressure energy."

Jan 1, 1976

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 Robert Keyes, Charle Knowles, Glenn Kendall, Gary Fletcher

"The metal mining industry in Canada has been dramatically affected by the changes that have occurred in the world mineral market place. World economic restructuring in the post ""oil shock"" period of the mid-1970s, greatly increased competition from suppliers in the developing countries, and commodity price and currency pressures have all combined to severely test Canadian competitiveness. In the new mining world, the rate of growth of demand for metals has declined due to product downsizing, materials substitution, and a relatively slower growth of over-all world economic activity.The interplay of market and political factors is complex. Canadian metal mining companies must compete in world markets against low-cost producers in developing nations whose priorities often appear to be centred on maximizing foreign exchange earnings to foster development goals and debt repayment. Many of these countries have high levels of government intervention in their mining industries. The result is a greatly in-creased number of suppliers all vying for a share of a world demand growing at a relatively slower rate than in the past. To be able to compete under these circumstances, Canadian companies have had to undertake 'survival mode' measures and look to new ways of doing things. In order to identify the effects that the recent market and economic trends have had on the Canadian metal mining industry, a study was undertaken by Canada Employment and Immigration to assess these changes and their implications for the metal mining workforce.The Canadian Occupational Projection System (COPS)—Sector Study Group with the cooperation of the Mining Association of Canada, undertook a human resource survey to gather current employment and occupation information. This formed an important part of the Canadian Occupational Projection System Metal Mining Sector Study. This article addresses the with survey results, a C.E.I.C. worker mobility study, and trends and issues that are changing the mix of jobs and the way they are being done.Figure 1 shows metal mining employment for the period from 1974 to 1984. It provides a clear picture of the employment swings that the industry has experienced especially during the recession period of 1981 to 1983. From 1981 to 1983, employment dropped by 14 000, from 68 000 to 54 764, and then dropped to its lowest point in 1984 of 52 783. We feel that employment in the medium term will be flat with growth in gold mines being largely offset by continued workforce rationalizing in other sectors.Perhaps the key point is that equivalent levels of output have been achieved in the recent period (1981-1984) with a workforce that is 25% smaller than it was in 1974. This also raises the questions which the COPS/MAC survey and COPS mobility study sought to clarify, namely, what jobs have been cut and where have these people gone? Equally important are the questions of occupational skill level changes, and what types of jobs are declining and which ones are becoming increasingly important, as economic and technological changes have altered the mining work place."

Jan 1, 1987

By C. R. Edwards

"The Cigar Lake project will develop the world’s second largest high grade uranium deposit. The Cigar Lake Phase 1 orebody contains approximately 226 million pounds U3O8 at an average grade of 20.7% U3O8. The mine, to be operated by Cameco Corporation, will use a unique water jet boring mining method to cut previously frozen ore. A distinctive ore handling design is required to handle the high grade ore slurry exiting the mining machines. The ore will be crushed and ground underground, with the ore slurry then pumped to surface. Loaded into purpose-designed containers on tractor-trailer units, the ore slurry will be trucked to Cogema Resources Incorporated’s McClean Lake mill. McClean Lake will leach all of the ore. Forty-three percent of the resulting uranium solution will remain at McClean Lake for processing into yellowcake. The other 57% of the uranium solution will be shipped to Cameco’s Rabbit Lake mill for processing into yellowcake there. Detailed design for the Cigar Lake project is now underway. Barring regulatory or market delays, production could start up as soon as early 2005.INTRODUCTIONThe Athabasca Basin in northern Saskatchewan hosts a number of large uranium mining and milling operations, including Cluff Lake, Key Lake, McArthur River, McClean Lake and Rabbit Lake. (Edwards 1988, Edwards 1992, Fielder 1998, Edwards and Oliver 2000, Edwards 2001) The latest project in the Athabasca Basin is the Cigar Lake project."

Jan 1, 2002

By S. M. Fatemi-Varzaneh

The AZ31 magnesium alloy is considered as a promising alloy in various applications and industries. Furthermore, to design a proper hot working process (rolling, forging and extrusion), the assessment of hot working behaviour of the alloy is necessitated. Accordingly, the hot deformation behaviour of AZ31 alloy was studied through hot compression testing method. The latter was carried out in a wide range of temperature (523 K to 783 K) and strain rates. The obtained true stress-true strain curves and final microstructures were examined and a partial melting was realized at 740 K. It was concluded that the presence of liquid did change the deformation mechanisms thereby affecting the flow behaviour.

Jan 1, 2005

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

"The first SkimAir flash flotation cell was installed in Outokumpu’s Hammaslahti Copper Concentrator in 1982 to prevent overgrinding of soft sulphides in the milling circuit. Since this first installation the popularity of the flash flotation has fluctuated depending on metal market conditions and regional preferences. Units have been installed in many commodities including copper, lead, gold, PGMs, silver and nickel. Though it has been successfully employed in many operations around the world, flash flotation technology is still not well understood by many in the mining industry. This paper will discuss aspects of flash flotation flowsheet development along with some of the metallurgical and engineering considerations required to successfully incorporate flash flotation into new or existing milling circuits. This paper will also try and debunk some of the myths that exist around flash flotation cells and their operation. Case studies of flash flotation implementation will be discussed.IntroductionModern flash flotation technology was developed several decades ago by Outokumpu, with the first commercial installation of this technology being at the Hammaslahti concentrator in Finland in 1982 (Kallioinen & Niitti, 1985). This was a relatively modestly sized SK80 cell producing final grade copper concentrate directly from the flash flotation cell operating in the grinding circuit. Since that time the size and number of flash flotation cells installed globally has grown considerably to the point where today, it is a widely known application of flotation technology for amenable ores. Owing to their long history in developing the technology, Outotec are the market leader with their SkimAir range of flash flotation cells. Though there is a general awareness of flash flotation process in the mineral processing industry, there is a lack of detailed understanding of the process and the benefits it can provide to new and existing operations."

Jan 1, 2017

By D. E. Pickett, J. A. Roland Faucher

"INTRODUCTIONMineral processing is undergoing growth and change at a rapid rate. The modern flotation process was discovered only in the mid-twenties, and uranium leaching in the mid-fifties. The growth of individual unit equipment size is also a recent development and is perhaps most dramatically illustrated by the increase in size and connected horsepower in grinding mills. It is also apparent in much of the equipment used in mining operations.These technical and mechanical developments have influenced the design of plants but not to the expected degree.Many metallurgists believed until recently that grinding an ore in the absence of steel results in a loEs of selectivity in the flotation. However results reported by Thornton (1), Fahlstrom (2), Canmet (3 & 4) have shown on the contrary better selectivity and improved recovery at a lower operating cost. According to the Aitik (2) plant results, the net difference in cost plus tailing value in favour of the two-stage autogeneous grinding circuit is in the order of 40 cents per ton of ore milled. Even a greater difference was indicated by the results obtained by Canmet on a sample supplied by Mattagami Lake Mines Ltd.Yet how many plants are taking advantage of these findings and how many plants are being converted. How much more improvement of the results would have been obtained if these tests had incorporated optimization of classification efficiency? By nature the mining industry and the mineral processors are conservative, and tend to emphasize the possible penalties for an unsuccessful innovation out of proportion to the potential rewards even for a significant improvement."

Jan 1, 1979

By F. Ford, J. Dong

"Laboratory and miniplant testwork was carried out to reject uranium from an Iron Oxide Copper Gold (IOCG) deposit that contains an average of 60-70 ppm uranium with high variability. The dominate copper bearing mineral is chalcopyrite with minor bornite and trace covellite. The main gangue minerals are iron-rich chlorite, quartz and magnetite. The main uranium-containing mineral is uraninite (UO2). Downstream processes require the maximum uranium level of no more than 80 ppm in final copper concentrate.Mineralogical examination reveals that uraninite particles are finely disseminated with grain size of less than a few microns in the deposit requiring fine regrind in order to liberate uraninite from chalcopyrite particles. A lab flowsheet was developed to include ultrafine regrind of the rougher concentrate to the particle size of 80% passing 11-13 µm with up to four stages of recleaning in flotation columns. Finer regrind to 80% passing 5-6 µm may continue to improve liberation but does not decrease uranium level in the final concentrate. In each of the successive recleaning stages by flotation column after fine regrind, uraninite is rejected into the column tailings, with the final copper gold concentrate containing less than 70 ppm uranium from a feed containing 83 ppm uranium. The conceptual flowsheet was further tested in an integrated, continuous miniplant showing average 94% copper recovery with average 74 ppm uranium. The uraninite particles that report to the final concentrate are either locked with chalcopyrite or entrained as liberated particles of less than 5 µm in size.IntroductionIron Oxide Copper Gold (IOCG) deposits are copper and gold ores hosted within a large body of iron oxide and are significant ore deposits for copper and gold (Williams, et al., 2005). These deposits can also contain economic levels of other metals such as uranium and rare earth elements. The known sizes of IOCG deposits range from 10 to 4,000 million tonnes with grade of 0.2-5% copper and 0.1-3 g/t gold. One of the greatest IOCG deposits is Olympic Dam in South Australia. It is the fourth largest copper deposit and the largest uranium deposit in the world. Gold and silver in the deposit also contribute significantly to the total revenue."

Jan 1, 2017

By L. Boyd, A. Charland, G. Potts, D. Fragomeni, N. O. Lotter

"The Raglan orebody and concentrator has been the subject of study in Process Mineralogy at Falconbridge since 1998. (Lotter and Tuzun, 1998) The orebody is classified into three distinct textural groups, or end members. These are referred to as disseminated, net-textured, and Massive Sulphides, and differ in terms of mineral grain size, nickel grade, hardness, and mineral association. In this paper, it will be shown that the sampling and characterisation of each end member on an individual basis develops a higher-level understanding of the processing requirements and behaviour of the mixture of ore as presented to the mill.The end members have been used in robust prediction of recovery at various grind size p80 from laboratory scale High Confidence Flotation Tests. Weighted mean mixtures of the end members have been mathematically combined to determine impact of textural distribution on metallurgical performance as a function of grind size.The ore end members also vary in hardness and breakage mechanism and have been used to model throughput capability for existing, optimized and retrofit grinding circuits. This modeling has provided a range of expected throughputs as the relative proportions of each end member varies.Finally, the differing grinding requirement per end member has led to the development of grinding and flotation strategy that increases rougher flotation recovery and provides flowsheet options for a concentrator expansion. This leads to further understanding of the plant performance as a function of ore mixture."

Jan 1, 2005