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Cobalt mostly occurs as a minor, but valuable, constituent in most nickel and a few copper ores, however it is not generally found alone in commercially viable deposits. Its concentration and extraction are therefore intimately linked to the recovery of the primary metals and the major task for the metallurgist is to extract cobalt of commercial grade from a much larger mass of either nickel or copper and sometimes both. With a particular focus on Vale Inco?s operations, this paper provides a brief overview of the mineralogy of the main deposits being currently exploited that contain cobalt as a co or by-product. The concentration and then extraction to metal are reviewed and some advances released into the public domain are discussed.

May 1, 2009

By N. I. Basuki, E. T. C. Spooner

"The Bongara area, northern Peru, contains Zn-Pb mineralization with characteristics typical of Mississippi Valley-type (MVT) systems. The northwest-southeast-trending late Triassic-Jurassic car¬bonate host rocks of the Pucará Group were locally replaced by early (D1) and late (D2) dolomite. Fluid inclusion microthermometric data from dolomite and sphalerite are typical of MVT ore fluids (78° to 187°C; ~15-23 wt.% CaCl2 equivalent), and do not show apparent covariation between temperature and salinity.Homogenization temperature data from D1 and D2 dolomite show a decrease from northern (mean Th = 138°C) to central (mean Th = 126°C) to southern areas (mean Th = 102°C), suggesting fluid flow from north to south. Assuming a geothermal gradient of ~30°C/km and an average surface temperature of ~20°C, the lower temperature limits might approximate the ambient host-rock temperatures, whereas the upper temperature limits may represent minimum temperatures of a deeper aquifer, probably at a maximum depth of ~6000 m. The lower temperature limits are also similar to the estimated temperatures if dolomitization and mineralization took place in the Late Cretaceous at ~2000-3000 m depth, probably during the formation of the Peruvian fold and thrust belt near the present day Peru-Ecuador border.Fluid inclusion data show that the fluids in each studied location had relatively uniform temperatures and salinities during dolomitization and mineralization. A significant salinity drop and a slight temperature decrease are observed during late calcite precipitation, suggesting mixing of brines with dilute, cooler fluids."

Jan 1, 2009

By K. G. Wheeland, J. E. Dutrizac, M. Wasserlauf, A. A. Condy

Numerous processes for the treatment of thiosalts in base metal milling effluents have been examined in the past decade. Flowsheets for thirteen processes are outlined, and cost estimates are presented for a base case of a 720 mi/h effluent flow containing 1400 mg/L thiosalts. The processes are ranked on the basis of Numerous processes for the treatment of thiosalts in base metal milling effluents have been examined in the past decade. Flowsheets for thirteen processes are outlined, and cost estimates are presented for a base case of a 720 mi/h effluent flow containing 1400 mg/L thiosalts. The processes are ranked on the basis of

Jan 1, 1988

By R. Amelunxen

"The molybdenite associated with copper porphyry ores is generally treated in a flotation circuit consisting of a separation and a cleaning section. In the last few years column flotation cells have replaced the numerous counter-current stages that were previously used in the cleaning section. Despite this, little has been published regarding the number of column cleaning stages required. Therefore a Moly flotation database is assembled with the objective of verifying the existence of a common upgrading profile. This can then be used as a guide in the prediction of the number of stages required to achieve a given concentrate grade.INTRODUCTIONAlthough the first use of Column Flotation was on copper flotation products, the popularity and understanding of their operation was not really achieved until they were widely implemented in Moly circuits in early 1983. The use of columns in Moly plants has since left a legacy of information, both published and unpublished. The data collected since that time has been used primarily used to establish column operating parameters and to determine upgrading potential within the circuit.Byproduct Moly generally occurs with porphyritic copper ores in concentrations less than 0.1% MoS2. As such, piloting a new moly ore to produce, say 5 Kg/Hr MoS2, in a slurry approximately 1 Lt/min (at 10% solids), requires a moly plant feed of about 570 Kg/Hr, which translates to a mill feed rate of 200 to 800 Tonnes per day (depending whether you deal with Chilean or Canadian ores). Piloting Moly for any lower tonnage would reduce the accuracy of the testwork.Thus a need exists to collect operating data in order to establish the existence of process relationships that could be used for feasibility and design purposes.The object of this paper is to expose a preliminary relationship that could be used for the purposes described above and to apply the findings to a preliminary design of a moly cleaning circuit flowsheet."

Jan 1, 1990

By Paul Gauthier

Aujourd?hui, avec un faible prix de l?or sur le marché, les opérateurs miniers doivent revoir leur façon de faire. La méthode de minage «Eureka» permet de réduire les coûts de production et d?accélérer la mise en production des chantiers. Les principales étapes du cycle de minage et les problématiques associées à l?utilisation de cette méthode à la Mine Bousquet y sont décrites.

Oct 1, 2001

By Ammar Henchiri, Godfrey McDonald

"Breakwater Tunisia S.A.’s Bougrine mine is located in a semi-arid region of Tunisia characterized with Triassic salt domes. Due to extensive agricultural land-use in the mine area, a zero-discharge tailings facility design and high water recycling rates to the concentrator were chosen to minimize the environmental impact to the surrounding area. The process water supply has an accumulation of naturally occurring salts due to high evaporation rates and the need to recycle 70% of the process water. The elevated salt content of the process water had an adverse effect on the efficiency of the flotation reagents, which led to the production of lower quality zinc concentrate.The impact of the water salinity on the zinc concentrate quality was documented by extensive laboratory testing. A feasibility study was prepared and a decision was made to install a reverse osmosis plant for desalination of the process water. A plant was constructed during 2000 which currently supplies up to 85 m3/hr of de-mineralized water, equal to approximately 45% of the total process water requirement. The salinity of the process water decreased from about ten to twelve grams per litre before installation to less than three grams per litre. Together with minor modifications to the concentrator circuit, Breakwater Tunisia has increased the zinc concentrate grade from 50% zinc to 55% zinc without compromising the zinc recovery rate of approximately 84%.This paper discusses the successful installation of a reverse osmosis desalination plant that allowed Breakwater Tunisia to improve the grade of the Bougrine mine zinc concentrate and thus increase the net smelter return.INTRODUCTIONBreakwater Resources Ltd., through a wholly owned subsidiary, Breakwater Tunisia S.A., acquired the Bougrine underground mine and related assets in September 1997. During the winter of 1997/1998, the company rehabilitated the mining equipment, modified the concentrator circuit, developed a new mine ventilation system and prepared a new mining production program. The mine was reopened on May 2, 1998 and was in commercial production as of June 1, 1998."

Jan 1, 2003

By I. C. L. Webster, G. E. Ray

"The magnetite-rich Heff Cu-Au skarn lies in the Quesnel Terrane of south-central British Columbia, approximately 26 km northeast of Kamloops. The skarn formed close to the northern margin of the Heffley Creek pluton, and is hosted by Carnian (Late Triassic) Nicola Group limestone. The Late Triassic pluton (208.1 ± 6.1 Ma, U-Pb zircon) is a composite body of alkaline affinity that includes dioritic, gabbroic, and magnetite-rich clinopyroxene ± olivine ultramafic phases.The skarn has been discontinuously traced along strike for more than 1 km, and individual skarn layers are up to 40 m thick. The most common non-opaque minerals are garnet, clinopyroxene, and carbonate, with lesser epidote, biotite, amphibole, and chlorite. Apatite locally forms more than 3 vol.% of the rock. Compositionally the garnet is a low Mn grandite averaging Pyr3-Grs41-Adr56 mol.%.Mineralization consists of lenses, up to 10 m thick, containing massive low Ti-V magnetite (avg. 0.03 wt.% TiO2 and 0.01 wt.% V2O3). Magnetite is associated with up to 20 vol.% pyrrhotite, lesser pyrite, and trace chalcopyrite and gold. There is a moderate enrichment in rare earth elements with assays up to 570 ppm La and 490 ppm Ce. The Heffley Creek pluton belongs to a suite of Late Triassic-Early Jurassic alkalic and Fe-rich intrusions that are widely developed throughout the Quesnel Terrane. Some host Cu-Au porphyry mineralization, but less commonly they are associated with magnetite-apatite veins such as at the Glen Iron mine and Magnet occurrence, or with magnetite-rich Cu-Au skarns such as the Heff occurrence.Although abundant low Ti magnetite is present in the Heff skarn, it does not appear to represent iron oxide copper- gold (IOCG) type mineralization. Microprobe analyses completed during this study show that low Ti magnetite is not a unique feature of IOCG deposits, but also characterizes some other types of hydrothermal mineralization. In British Columbia these include some alkalic porphyry-related magnetite-apatite veins in the Quesnel Terrane, as well as the well-known Wrangellia-hosted Fe skarn deposits. Thus, low Ti magnetite appears to be a common signature of many magmatic hydrothermal deposits in contrast to the high Ti primary magnetite found in most igneous rocks."

Jan 1, 2007

By P. A. Witt

"Highland Valley Copper is a conventional truck-shovel mining and flotation concentrator operation located 75 km southwest of Kamloops, British Columbia (Fig. 1).The ore is situated within a porphyry copper deposit and is mined at a rate of 135,000 mt/day from two separate open pits. The nearby mill produces concentrates containing 375 million pounds of copper and 5 million pounds of molybdenum metal yearly. In the Valley pit, head grades are roughly 0.40% Cu at a 0.23% Cu equivalent cut-off. The Valley pit strip ratio currently sits at 0.55:1 with waste quantities made up of separate rock and unconsolidated overburden units. From the mill, concentrates are trucked to nearby Ashcroft and then hauled by rail to ocean port facilities in Vancouver. The mine employs 950 people and is planned to operate until 2009. The operation is a partnership between Teck Cominco (63.9%), BHP Billiton (33.6%), and others (2.5%). Management is shared by the two principal owners and directed by a management committee."

Jan 1, 2005

By Lutz Markworth, Evren Ören

"The worldwide demand of ores and the depletion of the high-purity deposits make it necessary to recover ores in increasingly finer size fractions in the feed material. The flotation technology of more than 40 years old plants was not able to recover the ultra fine material. Those slurry tailings ponds now have the chance to be re-processed with PNEUFLOT® technology.The bubble sizes of different flotation technologies have a huge influence of the results especially regarding the recovery of the ultra fine particle sizes.PNEUFLOT® technology of HUMBOLDT WEDAG Coal & Minerals Technology GmbH in Germany was applied to ultra fine Phosphate, Copper and Platinum ores. The results will be presented in this paper.Conventional technology like agitator flotation has its limits in the flotation of fines due to turbulences in the cell. The position of the agitator influences the recovery of the fines. A deep impeller generates a higher froth zone. This helps to catch the medium fines. Due to the static head of the slurry inside the cell, compressed air is required for such cell designs.Column flotation is well known for a good selectivity without having in the first cell a good recovery. This leads to invest in several cleaning stages to reach an acceptable recovery. Further more, compressed air is required to generate the air bubbles to the flotation process, which are much bigger than with PNEUFLOT® technology applied.INTRODUCTIONHigh metal prices are actually the basis to invest in poor deposits or deposits with very fine intergrown ores which have to be milled down to ultra fine powders less than 60 micron. The liberation grade has to be determined by a mineralogical analysis. Polish sections have to be prepared and interpreted by using of a microscope. Figure 1 and figure 2 are showing polish sections of a platinum-nickel ore from Petchenga Nickel at Zapolyarni Mine in Russia. The head grades for rich ore are for copper between 0.05 – 0.15%, for nickel between 3 – 7% and for platinum group minerals approx. 0.15 oz/t. With an efficient flotation technology it can be upgraded to 20 oz/t."

Jan 1, 2009

By John A. Herbst, Xiangjun Qiu

"Prediction of wear on a microscale level in mineral processing equipment turns out to be a challenging undertaking. This is particularly true for cases in which the objective is to use such predictions for wear parts design. The key to obtaining such predictions has turned out to be the use of physics based models along with phenomenological constitutive equations. In this paper, two components of the HFS tool set, one for particles (DEM) and one for slurry (MPF), are used for modeling. These tools are applied to the simulation of wear of SAG/AG shell lifters/plates and wear in slurry pumps. In each case wear predictions are validated with plant measurements.INTRODUCTIONHigh Fidelity Simulation (HFS) has emerged as an important tool set for mineral processing plant equipment design and optimization (Herbst and Potapov, 2003; Herbst and Nordell, 2002; Herbst and Lichter, 2006). This tool set consists of Discrete Element Modeling (DEM) of particle motion, Multi-Phase Flow (MPF) for liquid motion, discrete grain breakage (DGB) for particle fragmentation and discrete grain liberation (DGL) for mineral liberation (Campbell, Potapov and Tsuji, 1997; Ferzinger and Peric, 1997; Potapov and Campbell, 1996; Herbst and Potapov, 2005).Three sample snapshots of basic HFS illustrating the use of each of the various types of mineral processing equipment are shown below.Figure 1 shows a snapshot of a DEM simulation of ball charge motion in a commercial scale Vertimill. DEM simulation involves simultaneous solution of Newton’s Laws of Motion for 400,000 balls."

Jan 1, 2007

By Claude Bazin

"The On-Stream Analyzer has proven and is still proving to be an extremely valuable tool for the control of flotation circuits. This paper examines the possibility of going further in the utilization of the provided assays using a real-time material balance program to calculate the distribution of solids within the streams of a circuit. Mass balance results can be used for process control, process analysis and detection of sensors malfunction. Examples from 3 Canadian and one American concentrators are presented to illustrate the potential of the method.IntroductionThe On-Stream Analyzer (OSA) has gained, over the last two decades, the status of key instrument for the control of flotation plants. The OSA is currently used in almost every sulphide flotation plant and its application in oxide mineral flotation plants is increasing. On-Stream Analyzers provide X-rays pulse counts that are converted into assays using multilinear regression programs. The estimated assays are passed to the flotation operators, via an operator console, or to control loops of various degrees of complexity (McKee, 1991) implemented in a Distributed Control System (DCS). Operators and/or controllers take control actions based on these assays to ensure an adequate operation of the plant. Although this application pays off very rapidly for the purchase of the OSA, one should ask: Could we get more from the OSA?Some plants reported the use of OSA measurements to process optimization (McKee, 1991). The optimization strategy is based upon economic indices calculated from metal recovery using the 2 product formulae (Wills, 1992, page 124). The 2 product formulae is however sensitive to measurement errors in the assays and can lead to considerable scatter in the calculated indices (Hodouin et al., 1993). Least squares algorithms provide an interesting alternative to filter out measurement errors (Spring, 1992). This paper presents a recursive least squares algorithm that estimates in a real time fashion the mass flow rates in a flotation plant using OSA and mass flow measurements. The algorithm is robust and its recursive structure is not demanding in terms of computation time and memory. The method was tested with data from four concentrators. Results of the material balance algorithm prove to be useful to detect sensors malfunction and may potentially be used for the control and optimization of flotation plants.The paper is divided into two sections. The first section gives a description of the proposed method. The mathematics of the method are kept to a minimum, since the detail is presented elsewhere (Bazin and Franklin, 1994). The second section shows the application of the method to different flotation plants."

Jan 1, 1995

By M. Kolahdoozan, H. Noori

"Molybdenite flotation at the Sarcheshmeh Copper Complex has been studied as a function of pulp potential controlled using two types of sodium sulfide (mineral and chemical origin). Air and either plant or laboratory nitrogen was used as a flotation carrier. Potential measurements were taken in the rougher cells as it was proved to be vital for molybdenite flotation. Flotation test with reducing potentials between -525 and -575 mv gave the highest molybdenum recovery (93%) and the lowest copper recovery of between 4 to 15% can be achieved. These potentials did not change considerably by adding increasing amounts of sodium sulfide. At more oxidizing potentials, i.e. more than -450 mv, the recovery of copper increases while the recovery of Molybdenite drops.INTRODUCTIONThe average copper ore feed grade to the Sarcheshmeh flotation circuit is typically set at about 1.2% Cu. to be delivered to processing unit is set at 1.2%. There is no control of molybdenum (Mo) which usually varies between 0.01 and 0.04%. During concentration, a Cu-Mo concentrate is produced by one stage of roughing, one stage of scavenging and two stages of cleaning. Final concentrate contains 0.5% of Mo and 32% of Cu while the particle size is 90% under 42 microns (325 mesh). Because of the high grade of Mo in this concentrate and economic interests, a molybdenite flotation circuit plant was built in 1984. This plant was designed to treat 1432 tons of Cu-Mo concentrate (on dry basis) and consists of one stage of roughing followed by seven stages of cleaning. After dewatering the concentrate contains 53.7% Mo which is dried and shipped overseas.The majority of molybdenite production worldwide comes as byproduct of copper porphyry ores. The Mo grade typically varies between 0.01 and 0.06% and accompanies chalcopyrite and chalcocite. Due to the hydrophobic nature of molybdenite, it can be floated along with copper sulfides. Thus the overall concentrate of Cu and Mo contains 0.2-1% of molybdenum as well as 20-42% of copper. To separate the Mo, Cu and Fe minerals, depressants are used. The most important of which are sodium sulfide, sodium hydrosulfide, Anomal D, sodium cyanide, ferropottasium and ferro-cyanide. The first three regeants have been extensively used for successfully treating porphyry ores [1]. In the molybdenum plant of the Sarcheshmeh Copper Complex only sodium sulfide has been used to date."

Jan 1, 2006

This paper describes the back analysis of the Pavoncelli tunnel, an hydraulic tunnel which was excavated between 1904 and 1915 in South of Italy and experienced severe damages during the 1980 Irpino-Lucano earthquake. A numerical simulation which is intended to study the behaviour of the tunnel during this seismic event is presented, also accounting for the swelling phenomenon that took place during and after construction.

May 1, 2009

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

In this project, low grade copper ore samples were obtained from two mining sites in the US, and they were chalcopyrite-rich (sample A) and conichalcite-rich (sample B) ore. Copper grades were 0.6% and 0.4% for the two samples, A and B, respectively. Leaching experiments were conducted by bottle roll tests for 24 hours, and various lixiviant systems were applied. Methanesulfonic acid (MSA) and glycine were used as alternative lixiviants to sulfuric acid. Oxidants including ferric ion and hydrogen peroxide were tested. The results showed the copper extraction of sample A increased after adding 1 g/L ferric ion in sulfuric acid and MSA solution, from 20% to 36%, but further increase was not observed with higher ferric ion concentration. The copper recovery increased significantly with H2O2 concentration, and over 80% copper recovery was obtained with 10% H2O2. For sample B, the copper dissolution kinetics were relatively fast and reached the maximum value in five hours. Around 60% copper were extracted in sulfuric acid and MSA solution. Copper recovery slightly increased after adding ferric ion and H2O2. Glycine is a weaker lixiviant for both samples, the copper extractions were 36% and 4% respectively. INTRODUCTION Chalcopyrite is the most abundant copper sulfide mineral on earth, and it is one of the most refractory copper minerals regarding chemical processing. The declining copper grade and depletion of copper oxide deposits stimulate the development of hydrometallurgical process to extract copper from chalcopyrite. The dissolution of chalcopyrite by ferric ion is normally illustrated as Equation (1) and (2) (Dutrizac & MacDonald, 1974): CuFeS2 + 4Fe3+ → Cu2+ + 5Fe2+ + 2S0 (1) CuFeS2 + 4Fe3+ + 3O2 + 2H2O → Cu2+ + 5Fe2+ + 2H2SO4 (2) However, slow kinetics are usually observed from chalcopyrite leaching at ambient temperature and pressure. Researchers attribute the slow kinetics to passivation during chalcopyrite dissolution, and different passivation products are also proposed (Klauber, 2008). In recent years, many efforts have made to develop new methods to extract copper from chalcopyrite, such as utilizing bacteria or stronger oxidant (Zhao et al., 2015; Ruiz-Sánchez & Lapidus, 2017).

Jan 1, 2019

By P. Dyas, H. Zouitt, D. M. Smith

"Falconbridge Copper's Lac Shortt gold mine is located in northern Quebec approximately 300 km northeast of Val D'Or and 100 km west of Chibougamau (Pig. 1). Engineering for the mill commenced in early 1983 with a feasibility study. The plant was commissioned in the fall of 1984 at a capital cost of approximately $12 million. Design capacity was 750 tpd which was increased in the fall of 1985 to the current level of 1200 tpd.The ore at Lac Shortt is free milling, grading an average of 5.5 g/t gold which is finely disseminated throughout the host rock. Pyrite at 3 to 5% by volume and traces of copper mineralization are also present.Some of the latest gold processing techniques known at the time of design were incorporated into the mill. These include carbon-in-pulp, pressure stripping, electrowinning of pregnant solution and induction furnace refining. The plant also features several innovations such as a unique interstage carbon retention screen in the CIP circuit and the outdoor location of the cyanidation feed thickener, mill solution tank and reagent storage silos despite -40° Celsius winter temperatures.This paper describes the current mill process and discusses some of the problems encountered during the first two years of the plant's operation. CRUSHINGThe Lac Shortt surface crushing facilities are located in a separate building, isolated from the wet processing circuits for dust and noise control reasons. The crushing plant equipment was originally utilized at the Manibridge operation in northern Manitoba where it had been designed to operate at 135 tph. However, at Lac Shortt a rate of only 80 tph has been achievable to date, mainly due to the hardness and frequently slabby breakage characteristics of the ore. Therefore, in order to meet fine ore requirements at the current mill throughput of 1200 tpd, the crushing circuit is run seven days a week. 24 hours a day. Availability has been averaging 65%."

Jan 1, 1987

"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 Jim Lauder, Russ Calow, Ken Maley, Michael Ounpuu, Stuart T. Caverly

"Stuart T. Caverly, Section Head XRF Laboratory, Jim Lauder, Systems Engineer, Russ Stuart T. Caverly, Section Head XRF Laboratory, Jim Lauder, Systems Engineer, Russ Concession Street, Lakefield, Ontario KOL 2HOAbstractOn-stream X-ray analyzers have become an integral part of modem milling operations. The calibration of these instruments is not difficult but must be performed carefully and with consideration for the principles of X-ray spectrometry. A discussion of successful calibration procedures as well as examples of several common mistakes is presented.IntroductionOn-stream X-ray analyzers (OSA) have become an integral part of modem mineral dressing plants. Advances in instrumentation and computer software make the analysis of process streams fast, accurate and precise. Proper instrument calibration that respects the fundamentals of X-ray spectrometry is essential if the data generated are to be reliable. Often the importance of this task is underestimated and delegated to a person with inadequate XRF training. Successful OSA calibration is the result of careful, systematic procedures.On-stream analysis is perhaps the most important tool that has been provided for the concentrator metallurgist. Combined with powerful, low cost PC's and distributed control systems, real-time elemental analysis affords today's metallurgist many opportunities to troubleshoot and optimize his process.Before OSA, operators had to be very experienced if they were to achieve good results. Even with hourly grab samples, most changes in control approach would still be based on visual cues from the circuit and gut instinct. Real-time analyses have changed that completely.The last two decades have seen a persistent drive to reduce production costs. Operations utilizing OSA have been the most successful in this endeavor. Direct benefits from the application of OSA are fairly obvious. Operators are able to make incremental changes in operational parameters (e.g. reagent addition, pH, cell level), and immediately monitor the effects. Variations in the characteristics of the mill feed can be identified and addressed immediately. More progressive operations have linked analyses to control loops to adjust process setpoints ( e.g. reagent additions), and to change them automatically according to formulas based on previous experience."

Jan 1, 1996

By T. Gammatikopoulos, C. Gibson, M. Aghamirian

Lithium is an alkali metal found in brine deposits in the United States, Chile and Argentina, as well as in hard rock deposits in Australia and North America. In hard rock deposits, spodumene (LiAl(Si2O6)) is the major economic lithium bearing mineral. Spodumene is typically upgraded through a combination of dense media separation, flotation and magnetic separation. One of the major spodumene concentrate quality specifications is the iron oxide content because it will help determine if the concentrate is considered ceramic grade for use in ceramics and glass or chemical grade for use in lithium ion batteries. The rejection of iron bearing silicate minerals from artificial ore composites (high amphibole and low amphibole, high quartz/feldspar) from a hard-rock spodumene deposit was investigated using magnetic separation and flotation. The efficacy of Wet High Intensity Magnetic Separation (WHIMS) in iron rejection was found to be dependent on the mineralogy of the iron-bearing silicate minerals including modal distribution, liberation and association. When magnetic separation was conducted prior to flotation, the Fe2O3 grade in the final flotation spodumene concentrate was reduced from ~3% to ~1% Fe2O3 , and improved lithium recovery in flotation was observed. It was determined that it was most effective to conduct WHIMS on the flotation feed after scrubbing and de-sliming because this reduced the required magnetic field to recover iron-bearing minerals, likely because slime coating was greatly reduced. Flotation collector screening of four different collectors with varying rosin acid content demonstrated a potential increase in selective flotation of spodumene over some iron silicate minerals with decreasing rosin acid content in the fatty acid collector. However, due to marginal difference in flotation results with the various collectors tested, further testing is required to confirm the observations made and establish a hypothesis regarding the effect of rosin acid content.

Jan 1, 2017

By R. B. Barlow, J. A. C. Fortescue

Originally developed for use in mineral exploration, regional geochemical mapping based on stream (and lake) sediment sampling is showing broader application in other areas of the earth sciences and in environmental science. The purpose of this paper is to focus attention on the role of regional geochemical mapping in relation to geological and environmental studies. This is achieved using a descriptive equation for the chemical composition of a stream-sediment sample and then relating it to the use of successive approximations in geochemical and environmental investigations. The procedure is further qualified with reference to time and process in the formation of regional geochemical patterns. Examples are included of studies based on stream sediments related to bedrock geology, surficial geology, ecology and man's effect on the geochemistry of the environment. The range of applications of regional geochemical mapping in earth and environmental studies is outlined and some conclusions drawn regarding the future development of geochemical mapping under Canadian conditions.

Jan 1, 1980

By Colin Hardie, Erik Bartsch, Guy Comeau

"The Xstrata Nickel Raglan Concentrator, located at the northern limit of Quebec’s Nunavik region has been in operation since 1997. Originally designed to process 800,000 tonnes per year of high grade nickel ore, plant capacity is currently approaching 1,200,000 tonnes per year due to an Optimization Project (FAG to SAG conversion) in 2005 and many recent processimprovements.In 2006, the Raglan Metallurgical Group with assistance from the Xstrata Process Support group decided to make SAG control one of its priorities in order to further increase throughput and improve stability. The original primary mill control logic delivered by the Optimisation Project in 2005 consisted of a simple PID loop controlling the mill charge (bearing pressure) through feed rate changes. Due to the multivariable, non-linear and disturbance dominated nature of the SAG circuit it was quickly found that this traditional PID control strategy was not able to adequately control the mill; resulting in poor stability, frequent operator interventions and less than optimum performance.This paper describes the successful integration of advanced field systems such as mill feed image analysis (Wipfrag) and crusher gap controller (ASRi), into a multi-variable fuzzy logic SAG mill controller. The process of how a strategy for control was developed and implemented directly in the existing control system (exploiting standard system capabilities) is discussed. It is also shown how this approach has provided mill automation which is simple, robust (despite erratic feed characteristics), and delivers both an increase in throughput and a reduction of variability.INTRODUCTIONOriginally commissioned as a Fully Autogenous Grinding (FAG) circuit in 1997, preparations to convert the Katinniq Concentrator Mill to SAG had in fact commenced as early as 1999, but were halted owing to alternative process improvements which achieved up to 1Mtpa as early as 2000. Up until this time, plant process controls had remained more or less static; modifications having been limited to those required by new equipment. Primary mill process controls and related measurements were at this stage limited to:"

Jan 1, 2008