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By W. H. MacLean, S. Liaghat

Abstract- The Key Tuffite is a thick (0.3 m to 6 m) and laterally extensive (-10 km) cherty, sulfide-bearing tuff unit in Archean greenstones in the Matagami mining district in northwestern Quebec. It lies at the contact of the Watson Lake Group and overlying Wabassee Group volcanic rocks, and is host to major Zn-Cu volcanogenic massive sulfide deposits. The tuff component is highly altered and its volcanic precursors are not identifiable by petrographie means. The tuff is mixed with a volcanic exhalative component comprising chert, carbonate and sulfides (pyrite, pyrrhotite, and minor sphalerite and chalcopyrite). The normative mineral composition of the Key Tuffite is 33% quartz, 28% sulfides, 16% sericite, 8% carbonate, 60Jo chlorite and 9% other minerals. In the vicinity of the Bell Allard and Orchan mines, the precursor tuff components are identified using immobile major and trace elements, as Watson Lake tholeiitic rhyolite (Zr/Y = 1.5 to 3.5, LaN/Ybn. = 1.7 to 2.8, Si02 = 72.5 ± 1.2 wt %, and Wabassee calc-alkaline andesite (Zr/Y =9, LaN/Ybn. = 4 to 8, Si02 = 56% to 65%). Immobile element computation techniques were used to calculate mass additions and losses in the conversion of the tuff to the Key Tuffite. Average net amounts of Fep3 (27% total iron), Si02 (14%), CaO (8%), S and K20 ( + 2%), were added, Na2O was removed (-2.8%), and MgO was over-all unchanged. Total net mass change was +63%, which comprises mainly exhalative additions, but also includes changes owing to hydrothermal alteration of the tuff component.

Jan 1, 1992

By J. Parreira

This paper presents a deterministic/stochastic model that was created to compare an autonomous haulage truck system to a manual one by calculating and estimating benchmarked Key Performance Indicators (KPIs) such as productivity, safety, breakdown frequencies, maintenance costs, labour costs, fuel consumption, tire wear, and haulage cycle times.

Aug 1, 2013

By Ronald Molnar

"High demand for metals is driving the exploitation of lower grade and more complex orebodies. These projects are often the initiatives of junior mining companies with limited financial resources. In addition, existing operations seek to enhance revenue from their existing metal recovery operations, through the production of value-added by-product metals and chemicals. Typically, hydrometallurgical circuits, often with novel chemistry, are required to exploit these new ores, to produce the multiplicity of products that will make a marginal project economical, or to increase the product range of an existing operation. Often, the mineral processing engineer is given the task of coordinating the development of a back-end hydrometallurgical flowsheet for their mineral processing project. This paper discusses the objectives that companies have when they commission the operation of a hydrometallurgical pilot plant. The paper goes on to enumerate some of the principal differences between mineral processing and hydrometallurgical pilot plants and the effect these have on the design, operability and potential pilot plant outcomes. Important factors include working with chemically reactive solutions and pulps, elevated temperatures operation, changing rheological properties of slurries, the complexity of integrated circuit flowsheets with long hold-up times and multiple recycle streams, and the need in some cases for extreme attention to purity and cleanliness. Examples will be drawn from the extensive experience base of SGS Minerals Services at the Lakefield site, in piloting both mineral processing and hydrometallurgical process flowsheets.INTRODUCTIONWe are currently experiencing a period of strong growth in the demand for metals. This in turn is turning the spotlight on a great many smaller mining companies and mining promotion ventures trying to tap into the rising metal demand. Some of these companies want to develop their properties and recover metals while others want to develop to the point that a major company will take an interest, or in some cases buy them out completely.With the heightened interest in metals, many orebodies that have been known about for years are being reconsidered for exploitation. Often, the reason they have not been developed to date is because of difficult metallurgy and marginal grades leading to marginal economic viability. In both cases the key that unlocks the resources is often the application of a novel metallurgical flowsheet, often a hydrometallurgical flowsheet."

Jan 1, 2006

By C. Larsen, I. Orford, L. Strah, M. Renaud, P. Radziszewski

"An AG/SAG mill was commissioned at the Brunswick mine concentrator in October 1998. This paper discusses the original shell top hat liner design for the bi-directional AG/SAG mill, observed liner wear, subsequent liner design modifications, and benefits.The original liners were chrome-moly steel Norsteel with rubber grates and rubber-lined pulp lifters. The design was based on experiences of other AG/SAG mills and recommendations by the liner supplier, Norcast. Liner design modifications were made in an iterative fashion after observing the wear rate profile of the liners; over ten liner sets were implemented. Shell liner design improvements were supported by a design of experiments approach in conjunction with discrete element method (DEM) charge motion simulations. Design optimization took into account lining costs and impacts on operating performance. The team approach to the liner design improvements process is described with emphasis on the application of the design of experiments. The liner wear history and mill operating performance are presented."

Jan 1, 2005

By B. Hart, J. Marois

"Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM–EDX), and Time of flight secondary ion mass spectroscopy (TOF-SIMS)were used to analyze pyrochlore grains from Niobec froth flotation plant. Samples from the mill feed, pyrochlore rougher feed, pyrochlore rougher concentrate, and tail were analyzed in order to identify a potential relationship between pyrochlore matrix composition and selective separation. SEM-EDX analyses indicate that pyrochlore grains with high Fe content appear to be less recoverable than those with a lower Fe content and that the flotation response is related to matrix Fe rather than Fe occurring as inclusions. TOF-SIMS was used to analyse the surface of high Fe and low Fe pyrochlore, in order to identify a potential relationship between pyrochlore matrix composition and the related effect on cationic collector adsorption (tallow diamine). Surface analyses of pyrochlore from a conditioning test show that species indicative of the collector favour the surface of Fe poor pyrochlore relative to the Fe rich variety. The results from the conditioning test illustrate a negative relationship between collector loading and the presence of Fe and related oxidation species. This study identifies the link between pyrochlore matrix Fe content and, the presence of surface oxidation products, to collector loading. Poor Fe rich pyrochlore recovery noted in the Niobec froth flotation plant may be partially explained by this mechanism.INTRODUCTIONPyrochlore, the most abundant niobium containing mineral (Perrault and Manker, 1981) is economically recovered in Brazil, China, and Canada (Niobec) (Kouptsidis et al., 2008). Since 1974 Niobec has been extracting niobium from the St-Honorécarbonatite deposit. Niobec is the only operating Nb extraction facility in North American and one of the three major world producers of ferroniobium (Dufresne and Goyette, 2004; Belzile, 2009).Flotation is the preferred and most cost-effective method for pyrochlore recovery (Burks, 1958; Shapolov and Polkin, 1958; Zakharov et al., 1967; Razvozzhaev and Nikiforov, 1972; Bogdanov et al., 1973; Abeidu, 1974; Raby and Desrochers, 1975; Wilson, 1979; Biss and Nadeau, 1982; Biss, 1985). With the aim of optimising the flotation process for the Niobec ore, numerous experiments were performed on the influence of surfactants and type of water to optimise pyrochlore recovery and grade during flotation (Gomez et al., 1987; Rao et al., 1988; Dufresne and Goyette, 2004; Belzile, 2009)."

Jan 1, 2013

A newly developed damage model was used in the study of rock fragmentation mechanisms involved in crater blasting. Simulations show that at the detonation of the explosive charge, a crushed zone around the explosive charge is formed due to compressive failure and then a strong pressure wave is sent out forming a pressurized ring that propagates at the dilatation wave velocity. As the pressurized ring leaves the crushed zone, two tensile stress components perpendicular to the radial stress are developed in response to the action of the radial pressure, causing tensile failure and forming a damage zone around the charge. The formation of this damage zone is quite independent of the depth of the explosive charge provided there is no interference by the reflection from the free face. When the pressurized ring reaches the free face, it is reflected there and causes rock failure on the ground surface that forms another damage zone. Under the simulation conditions, it is revealed that the depth of charge is a factor controlling the relationship between the two damage zones. At a depth smaller than the optimum, the two damage zones coalesce into one and there is excessive rock breakage; otherwise, the two damage zones tend to isolate from each other with the increase in the depth of charge. Calculations of fragmentation indicate that the average fragment size increases and the uniformity of fragments decreases when the depth of charge increases as observed in practical blasting.

Jan 1, 1998

By W. W. Culver

The paper explores the substance, circumstances and significance of the Whelpley and Storer Copper Process. The 1866 Whelpley and Storer patent specified a process combining mechanical and chemical engineering. The process called for a down-drafting shaft furnace with a horizontal flue connected at the bottom of the shaft. Powdered sulphide ore was roasted in the shaft and then sent forward fully oxidized to a bath of sulphuric acid and/or calcium chloride. The “water furnace” was developed in Boston, at a time when the city was home to most Michigan copper mining companies. The process was field-tested at Quebec’s Harvey Hill copper mine. In 1865 James Douglas, Jr. took over management of the Harvey Hill mine with the challenge of saving the family investment. He needed a way to make money from low-grade sulphides. Through his relationship with chemist T. Sterry Hunt, Douglas learned of a possible way ahead using the process developed by Whelpley and Storer. The paper confirms the centrality of publications, meetings, and networking in the advancement of metallurgy. The process is of interest historically, as much as anything, because it is one of the pillars of James Douglas’ distinguished career in copper. INTRODUCTION At the 1866 meeting of the American Association for the Advancement of Science (AAAS) in Buffalo, New York, T. Sterry Hunt (1826–1892) read a paper “On the Metallurgical System of Messrs. Whelpley and Storer.” The paper is part of a chain of events that constitute the foundation of James Douglas’ (1837–1918) success in the copper mining industry. To understand the career of Douglas over the early years of modern copper mining, we must necessarily start with Whelpley and Storer. Going back to Hunt’s paper, he concluded his remarks by asserting that the Whelpley and Storer Process was “capable of such wide and varied application, that it is probably destined to have a very important influence on the industry of the world” (Hunt, 1867a). He reached this conclusion reasoning that the process had overcome a critical metallurgical hurdle (Hunt, 1867a). Hunt, a geo-chemist in modern terms, recalled that the chemist of those years easily separated copper from “sulphuretted” ores by converting it to a soluble salt from which pure metal was precipitated by “an equivalent of iron.” The problem was to “…apply this principle in the working of copper ores on a great scale...” (Hunt, 1867a). Hunt noted that this very problem had “…engaged the attention of many metallurgists, and has given rise to various processes for obtaining copper by the moist way, many of which are nearly or quite perfect in their operation, but are lacking in practicability and cheapness” (Hunt, 1867a). Hunt thought Whelpley and Storer had overcome the low-grade sulphide hurdle with a commercially viable engineering breakthrough. Yet in the history of copper metallurgy, the process is missing. What happened?

Jan 1, 2019

By Chris Larsen, Ian Orford, Marilene Renaud, Mike Cooper, Lud Strah

"An AG/SAG mill was commissioned at the Brunswick Mine concentrator in October 1998. This paper discusses the original liner design for the bi-directional AG/SAG mill, observed liner wear, subsequent liner design modifications, and benefits. The mill liners consist of steel top hat shell liners, steel end liners, rubber grates and rubber lined pulp lifters.Lifter profile and plate thickness measurements were made on monthly shop days. Trends of wear rates were used to project when liners required replacement. Wear profile information was also used to determine where liner re-design would improve wear life or minimize scrap loss. Charge motion simulation modeling was used as a tool to assist liner design modifications.INTRODUCTIONThe Noranda Inc. Brunswick Mine, located near Bathurst, New Brunswick, is a large underground lead/zinc mine with a nominal production rate of 10,000 tonnes per day. The Brunswick concentrator commenced operation in 1964 with conventional surface crushing followed by rod and ball milling to reduce run of mine ore to the required size to feed two parallel flotation circuits. In 1998 the AG (autogenous grinding) mill was commissioned for a nominal production rate of 9,000 tonnes per day replacing two surface crushing plants, three rod mills and three primary ball mills. In May of 1999 the mining rate was increased and the service of the AG mill was changed to a SAG (semi-autogenous grinding) mill with the addition of 4 inch steel balls (4% volume). The mill operates in closed circuit with 0.66 meter horizontal cyclones to produce a ground product of 90 micron nominal size (K80).The AG/SAG mill liners are steel (Norsteel, chrome-moly steel) with rubber grates and rubber lined pulp lifters.The original liner design was based on studying other AG/SAG mills and recommendations by the liner supplier, Norcast. Design factors taken into account were total cost of lining (including material and labour), protection of mill shell and impact on operating performance."

Jan 1, 2003

By J. S. Redpath

There appears to a definite trend toward the hoisting of greater tonnages from greater depths. There is every indication that this trend will continue and we feel that improvements in the design, fabrication and installation of mine guides will be of significant importance in the future. The present state of the art in mine-shaft guide systems is reviewed and the parameters required for improvement are derived in this paper. Finally, a proposal is made for a new steel guide system which meets the parameters and is economical to fabricate and install.

Jan 1, 1977

By J. P. Thomson

Magnesium alloys are steadily improving their market share as structural components especially in the transportation sector. Therefore, there is a great deal of interest from the automotive and the metal casting industry to develop viable economic casting processes for magnesium-base alloys. This paper summarizes the preliminary results on the continuing projects within CANMET-MTL on casting processes such as gravity and low-pressure casting in sand molds, permanent molds and lost foam.

Jan 1, 2004

By S. McCalpine, W. Muir, P. J. Downey

"Golden Bear Operating Company Ltd. (GBOC) was a joint venture between Chevron Minerals Ltd. and North American Metals Corp. that was formed for the development of the Golden Bear Project. The mine is located at Muddy Lake, Western British Columbia, approximately 80 km northwest of Telegraph Creek and 135 km west of Dease Lake (see Figure 1). Road access to the mine was developed by Golden Bear and consists of a radio controlled 155 km gravel road originating at highway 114.A feasibility study was completed in 1987 and project approval was finalized in 1988 with Golden Bear issuing a ""Request For Proposal"" for detailed engineering in May 1988. Golden Bear also commenced negotiating with vendors at this time for the supply of the two principal process equipment packages: the dry grinding and classification system and the whole ore roaster package.Process plant engineering and plant construction was completed in October 1989 with plant startup commencing in November 1989. Two months into the commissioning phase it became apparent that the plant, as designed, would not achieve the anticipated production targets.Kilborn Engineering Pacific were subsequently contracted by GBOC to review and modify the plant design, assist the operating personnel with plant commissioning and startup and provide operator training.This Paper describes some of the problems encountered during the startup and the plant modifications incorporated to achieve design parameters."

Jan 1, 1992

"NI 43-101 is a rule that governs how issuers disclose scientific and technical information about mineral projects to the public in Canada. The disclosure standards apply to oral statements as well as written documents and websites. NI 43-101 does not apply to disclosure concerning petroleum, natural gas, bituminous sands or shales, groundwater, or coal be methane. NI 43-101 first came into force on Feb. 1, 2001 and was revised in December 30, 2005. As a “National Instrument”, the law has been passed in each provincial and territorial legislature across Canada.“PART 1 DEFINITIONS AND INTERPRETATION 1.1 Definitions - In this Instrument “adjacent property” means a property(a) in which the issuer does not have an interest;(b) that has a boundary reasonablyproximate to the propertybeing reported on; and (c) that has geological characteristics similar to those of the property being reported on; “data verification” means the process of confirming that data has been generated withproper procedures, has been accurately transcribed from the original source and is suitable to be used; “development property” means a property that is being prepared for mineral production and for which economic viability has been demonstrated by a feasibility study; “disclosure” means any oralstatement orwritten disclosure made by oron behalf of an issuer and intended to be, orreasonablylikely to be, made available to the public in a jurisdiction of Canada, whether or not filed under securitieslegislation, but does not include written disclosure that is made available to the public only by reason of having been filed with a government or agencyof government pursuant to a requirement of lawother than securities legislation; “early stage exploration property” means a property that has(a) no current mineral resources or mineral reserves defined; and (b) no drilling or trenching proposed; in a technical report being filed in a local jurisdiction; “exploration information” means geological, geophysical, geochemical, sampling, drilling, trenching, analytical testing,assaying, mineralogical, metallurgical and other similar information concerning a particular property that is derived fromactivities undertaken to locate, investigate, define or delineate a mineral prospect or mineral deposit; “feasibility study” means a comprehensive studyof a mineral deposit in which all geological, engineering, legal,operating, economic, social, environmental and other relevant factors are considered in sufficient detail that it could reasonably serve as the basis for a final decision by a financial institution to finance the development of the deposit for mineral production; “historical estimate” means an estimate of mineral resources or mineral reserves prepared prior to February 1, 2001;“IMMM Reporting Code” means the classification system and definitions of mineral resources and mineral reservesapproved by The Institution of Materials, Minerals, and Mining in the United Kingdom, as amended; “JORC Code”means the Australasian Code for Reporting of Mineral Resources and Ore Reserves prepared by the Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute ofGeoscientists and Mineral Council of Australia, as amended; “mineral project” means any exploration, development or production activity, including a royalty interest or similarinterest in these activities, in respect of diamonds, natural solid inorganic material, or natural solid fossilized organic material including base and precious metals, coal, and industrial minerals;"

Jan 1, 2003

By Mary A. Wells, Amir Hadadzadeh, Mark A. Whitney, Stephen F. Corbin

In an effort to produce less expensive titanium sheet via roll compaction, the room temperature compaction behavior of titanium sponge granules (99.9% pure, Alfa Aesar) was studied under uniaxial die compaction. The titanium sponge granules were irregularly shaped, with a high degree of porosity, having a maximum particle size of 3mm. Manual die compaction was conducted using a Carver hand press, in a hardened tool steel die with 12.61 mm inner diameter. Uniaxial die compaction in a hardened tool steel die with 9.50 mm inner diameter was also performed using a Gleeble® 3500 thermal-mechanical simulation testing system which allowed for controlled deformation rates. Compaction behavior of the titanium sponge was studied using well-established compaction equations (Heckel, Panelli-Filho and Ge), and it was observed that compaction rate influences the room temperature compaction behavior of this material. The Heckel analysis of the titanium sponge showed that the behavior of the material could be analyzed in two compaction pressure regimes. In the low pressure regime (<100 MPa) the granules exhibited high compressibility, while; in the high pressure regime (>100 MPa) lower compressibility of the titanium sponge was observed.

Jan 1, 2015

By John Plecash

This paper comprises a general outline of all of the developments, including the history, geology, mining, milling, power and transportation installations, at the gold mining operation of La Luz Mines Limited and the copper mining operation of its wholly-owned subsidiary, Rosita Mines Limited, both located in north-central Nicaragua. The low-grade, gold-bearing ore-bodies of La Luz Mines, contained in highly fractured and folded Lower Cretaceous sedimentary rocks, were from 1909 to 1928, mined and treated by primitive methods by the La Luz and Los Angeles Mining Company. The abandoned property was acquired by La Luz Mines Limited in 1936, and was equipped with modern machinery and put into production in 1939. Between 1939 and 1948, the daily rate of production was in-creased from 300 tons per day to 2,-000 ton per day. The ore reserves available for open-pit mining were depleted in 1954. Since then, the entire production has come from under-ground operations.

Jan 1, 1963

"10.1. IntroductionAs discussed by Westland (1981), the six platinum-group elements (PGE) belong to the Group VIII transition metals, to which iron, nickel and cobalt also belong. The chemical similarity between these nine metals accounts for the fact that they tend to be concentrated together as a result of geological processes. These processes started to effect the distribution of these metals at the very beginning of the earth's history.The first line in Table 1 gives the concentration of nickel and certain other Group VIII transition metals in carbonaceous chondrites, those meteorites with a composition that is believed to reflect best the composition of our planetary system apart from hydrogen and helium. The second line is the estimated concentration of the same elements in the earth as a whole. It is seen that these two estimates are quite similar, the earth being perhaps 2 to 3 times richer in these particular metals than the planetary system as a whole. The reason for this is not fully understood, but it may be due to the earth being formed by the accumulation and capture of a greater proportion of iron (and therefore siderophile-rich) than stoney (and therefore siderophile-poor) planetesimals than the planetary system itself.The third line in Table 1 is the average composition of the crust of the earth. With the exception of iron, all of the Group VIII transition elements are rare in the crust, present at concentrations of It tOO to Itt ,000 of that of the bulk earth. This is because the outstanding chemical characteristic of this group of elements is their siderophile nature; that is, their tendency to alloy with metallic iron. Because of this, once the earth became molten very early in its life history, these elements dissolved in the molten iron present at this stage and were removed from the outer accessible parts as this dense liquid sank to the centre of the earth to form the core. Although iron was the main instrument of concentration of the Group VIII metals, its much greater over-all abundance and its ability to combine with oxygen more easily than the others in the group means that significant amounts still remain in the oxidized portions of the earth.The fact that most of the Group VIII metals are available to use in workable concentrations at all is that they are 5 to 30 times more concentrated in the earth's mantle than the crust, as shown in line 4 of Table I. There has been a constant, if slow, interchange of matter between the mantle and the overlying crust throughout most of the earth's history and, under certain circumstances, this interchange has given rise to economic concentrations of metals."

Jan 1, 1979

By L. Garycki, P. Poks, R. Urbaniak, T. Gabka

In 2016 at Głogów Copper Smelter KGHM Polska Miedź S.A., after shutting down the shaft furnaces new FSF was launched. Currently, it is the only smelter with two direct to blister flash smelting furnaces in operation. The main difference between the vessels are the dimensions and production capacity. The new furnace design output is about 30% higher compared to the old flash smelting furnace working for 40 years. The paper presents a comparison of both FSFs operation, differences in technology and the way to optimize the process to maximize efficiency. INTRODUCTION KGHM Polska Miedź S.A. is the only company in Poland (eastern part of Europe) that extracts and processes copper ores. It is located in the south west of Poland and this region is called the "Copper Basin”. KGHM PM S.A. consists of three underground mines: Lubin, Polkowice-Sieroszowice, Rudna, concentrator plants, a tailings pond plant, three copper plants: Legnica, Głogów and Cedynia wire rod plant in Orsk. The publication relates to the operation of the furnaces in Głogów (the plant in Głogów consists of Głogów 1 and Głogów 2 which form integrated smelting and refining facilities). In 2016, after closure of the shaft furnaces technologies in the Głogów 1, a new FSF commenced operation. The simplified process flow sheets are given in Figure 1 and 2. Technological schemes are similar, but due to the differences in them, they will be discussed separately. Głogów 1 Enriched ores are discharged and directed to the feed preparation plant. Delivered concentrates are built up on the three bedding aisles in appropriate proportions. The concentrates are distributed in even layers in one of the three aisles. Aisle emptying is done with a blending machine which cuts across the concentrate layers and collects thus blended material, sending it via belt conveyors to a storage bin. From the cross- blending machine and conveyor assembly, the mixture of concentrates is directed to drying in the steam dryer. Part of the charge is directed to the FSF and part to the roaster for carbon elimination. Known in the world roasters are used to eliminate sulfur compounds or arsenic. In the case of KGHM deposits, the aim of the process is to reduce the energy value of the feed by eliminating carbon and converting sulfur from sulfide to sulfate. Changing the nature of exothermic to endothermic material is crucial in the case of furnace operation with design performance. Roaster is a separate furnace with an innovative character.

Jan 1, 2019

By Joseph L. Fournier

Suncor Oil Sands employs delayed coking technology in converting bitumen into synthetic crude oil. Currently up to 10,000 m3 of delayed coke (coke) is produced per day as a byproduct of the upgrading process, of which up to 9,000 m3 per day is placed in dry storage on Lease 86/17. A review was completed to examine the case history of leachate potential experiments from the dry storage of coke and the environmental relevance of coke leachate studies conducted over the past decade. The review included an evaluation of the potential impacts of environmental conditions within the location of coke storage, including precipitation pH, as well as daily and annual ozone trends. Coke leachate potential has historically been characterized using standard leachate testing protocols (i.e., TLCP, SPLP) together with other studies that have employed strong acids and oxidizing agents in the extraction fluids. The present paper highlights prevailing conditions in the Athabasca Valley air-shed with emphasis given to ambient ozone (oxidizers), as well as precipitation pH and acid input deposition rates, and will demonstrate that TCLP / SPLP tests lack the intended environmental relevance relative to the conditions under which coke is stored.

May 1, 2011

By Tatiana Ravani von Ow, Leandro Bomvisinho

"The size of mills driven by ring-gear or by a gearless solution has significantly increased in the last years. This has created additional challenges for the driven equipment. The requirements for the mechanical devices and the power grid have become more demanding. Controlled soft starting and operation, especially in dual pinion mills, as well as the protection of the equipment has gained importance. The selection of the drive solution for the mill therefore becomes more critical. Besides the classical criteria such as performance, efficiency and capital costs other factors come in the evaluation of the system such as flexibility and optimization of operation, reliability and the ageing of the grinding equipment.Variable speed solutions offer significant advantages over conventional fixed speed drives due to their application specific features and process optimization capabilities, even for ball mills where these are not seen yet as a must.The initial capital costs are higher than some of the direct on-line solutions however the benefits for the operation during the lifetime of the mill generated by the use of converter solutions justify the additional higher investment.INTRODUCTIONThe method of powering mills such as AG, SAG and Ball has a long and technically interesting history. It can be said; almost every decade in the last half century had its own trend. The trend was dominated by the market demand, by the process development and requirement of the mechanical and the electrical technology but mostly by the price of the applied technology.All has started about 50 years ago with mill diameters less than 20 feet driven by fix speed synchronous or wound rotor motors with the power of about 2 MW. Around 10 years later, the mill sizes increased, but the necessary torque could not be transmitted by one pinion therefore dual pinion solutions were developed to power the mills. However, realization of the dual pinion solution was only possible when load could be evenly shared between the two pinions."

Jan 1, 2010

By Daniel Hodouin, Claude Bazin

"This paper examines the economic advantages of adapting the production grade and recovery targets of a flotation circuit as a function of metal prices. The study is periormed using a steady state simulator for a Cu-Zn differential flotation circuit operating under the following strategies of 1) Maintaining constant operating targets, 2) Maximizing individual circuit Net Smelter Return and 3) Maximizing the global Cu-Zn circuit efficiency. Results are compared to assess whether or not one of the strategies produces benefits significantly higher than the others. A discussion of the tools required to achieve such a kind of control completes the paper.Paper not Available at Time of Publication"

Jan 1, 1997

By S. A. H Tyrrell, R. Rotzinger

"Taseko Mines Limited recommenced operation of the Gibraltar copper-molybdenum mine in 2004 and embarked on series of development projects to modernize the mine and increase throughput capacity. The Gibraltar Development Plan 3 (GDP3) project included a second stand-alone copper-molybdenum concentrator, a stand-alone molybdenum separation plant and associated services. Ausenco was contracted to commence the detailed design in 2Q2011, commissioning commenced in 4Q2012 and first ore was processed in 1Q2013. This paper discusses the design, implementation and commissioning of the GDP3 Concentrator.INTRODUCTION The Gibraltar Mine (Gibraltar) property is located in the Cariboo Region of south central British Columbia, approximately 360 kilometers northeast of Vancouver. The site is accessed via an 18 kilometer paved road from the town of McLeese Lake, which is located on the province’s main north-south highway between the cities of Williams Lake and Quesnel. Gibraltar was originally developed by Placer Development and commenced production in 1972. Gibraltar was acquired, while on care and maintenance, by Taseko Mines Limited (Taseko) in 1999 during a period of unusually low metal prices. Taseko recommenced operations at Gibraltar in 2004, and embarked on series of development projects to modernize the mine and increase throughput capacity. The 1972 Gibraltar process flowsheet incorporated two-stage crushing followed by rod and ball milling and flotation. In 2008 Gibraltar completed their first development stage that included the installation of a SAG mill, converting the existing rod mills to ball mills and adding additional flotation capacity. Gibraltar continued development with the installation of an in-pit primary crusher, expansion of the bulk regrind circuit, expansion of the cleaner flotation circuit, replacement of the tailings pumping system and replacement of the concentrate filters and dryer."

Jan 1, 2014