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By N. Mejia, Z. Xiao, D. Fragomini, A. R. Laplante

"The adaptation to platinum-group minerals (PGMs) of a protocol developed to predict gold recovery by gravity is presented. The protocol is based on three different data sets: ore characterization of gravity-recoverable minerals, description of their behaviour in cyclones and ball mills, and performance of recovery units. Examples of these are given. It is shown that the gravity-recoverable PGM (GRPGM) content can be very high. A case study at the Clarabelle mill is presented. Sperrylite is the dominant platinum mineral, and its partition curve is very similar to that of gold, despite its lower density. Its grinding kinetics is significantly higher than for gold. As a result, sperrylite accumulates in finer sizes than native gold, but can still be recovered by gravity or flash flotation. Recovery projections based on gravity recoverable data are presented.BACKGROUNDReliable modeling of gold recovery by gravity or flash flotation from a grinding circuit is based on the ability to describe the properties of gold-bearing particles in the ore, their behaviour in grinding and classification units and the performance of the equipment used for recovery, be it gravity or flotation. This is shown in Figure 1."

Jan 1, 2004

By Jean M. Richardson, Steven R. Williams

"Geometallurgical mapping is a new team-based approach that documents variability within an orebody and quantifies the impact of geology (host rocks, alteration and structure) and mineralogy on grinding, metallurgical response and metal recovery processes. The quantitative, spatially constrained database that results can be readily integrated into 3-D block models and mine planning activities. Thus it is an important tool to reduce the technical risk associated with new mine developments or expansions.Normally undertaken during pre-feasibility or feasibility planning stages, the first step of geometallurgical mapping is to review the geology, mineralogy and other critical parameters and construct a geometallurgical matrix. This matrix provides an objective base to then guide sampling and/or compositing activity for physical property and metallurgical testing. Depending on the project, an array of testing techniques can be used to characterize the ore and feed data into the geometallurgical model.While the range and number of tests needed is project-dependant, the geometallurgical mapping approach allows the development of empirical models or interdependent relationships, grounded by spatially-constrained real data. Extensive data sets collected using less expensive testing methods can be meaningfully correlated with results from complex specialty tests to yield realistic metallurgical recovery data.With geometallurgical mapping completed, the resulting database can be integrated into an overall 3-D block mine model. This means that metallurgical response can be used to realistically forecast the recoveries of specific blocks, perhaps sampled only by drilling. Mine planning can then incorporate the forecasted metallurgical response and generate future project cash-flows; opening the door to economic optimization of the mine exploitation."

Jan 1, 2004

By G. Couture, J. -F. Dubé, F. Letarte-Lavoie

"The Xstrata Nickel Raglan concentrator, located in Quebec’s Nunavik region, has been in operation since 1997. Originally designed to process 800,000 tonnes per year of high-grade nickel ore, the plant’s current capacity is 1.3 million tonnes per year due to various optimization projects. In 2011 and 2012, the Metallurgical group, with assistance from BBA, updated and optimized the variables affecting SAG throughput in order to optimize process stability while maintaining maximum plant throughput. This project consisted of reviewing the control strategy and completely updating the pre-existing Fuzzy Logic controller. This paper describes the successful update of the controller including a complete revision of control rules, a new process control strategy and the integration of new process variables, most notably mill rotational speed. It will also show how this new approach has provided a simple and robust way of delivering both an increase in throughput while reducing process variability.INTRODUCTIONThe Xstrata Nickel Raglan Mine concentrator is located in Northern Quebec along the 62th parallel. It has been in operation since 1997 and was originally designed to treat 800,000 tonnes of ore annually. The Raglan Agreement held with the Makivik Corporation and the Inuit communities limits the annual tonnage of ore that can be processed at 1.32 million tonnes.The ore is processed in a 24 foot variable speed, semi-autogenous grinding mill (SAG). The conversion from Autogenous Grinding (AG) to SAG was completed in 2006. Before the ore is processed by the SAG, its size is analyzed by a Wipfrag camera that provides a granulometry estimate. A cone crusher reduces the SAG’s discharge screen’s oversize material. A 14 foot diameter ball mill ensures final grinding before the flotation stage.Many control strategies were used at the SAG over the past few years. Fuzzy Logic was first used in 2007 in order to control tonnage feed to the SAG. This first version only measured the value of the variables without taking into account their rate of change. Revisions were made over the course of the last few years to improve controller performance. Other variables were added such as slurry density and crusher Closed Side Setting (CSS). The previous revision of the Fuzzy Logic was done in 2009 with a review of the rules only."

Jan 1, 2013

By D. R. Tesarik

Researchers from the National Institute for Occupational Safety and Health (NIOSH)1 and engineers from Placer Dome, Inc.2, conducted an underground rockfill span test at the Turquoise Ridge Mine near Golconda, Nevada, USA with the purpose of improving safety and increasing productivity by using a bulk mining method instead of drift and fill. A rockfill sill was constructed by mining and backfilling six adjacent, parallel drifts and then undercutting the sill with a 13.7 m (45 ft) wide and 30.5 m (100 ft) long room. Displacement measurements from vertical borehole extensometers installed in the mine roof and rockfill indicated that the sill remained stable with a maximum vertical deformation of less than 5 mm (0.2 in). These results were confirmed by visual observations and calculations from a validated three-dimensional numeric model of the sill. The numeric model was also used to simulate load on the sill produced by dislodged roof material in the shape of a 11.0 m- (36 ft-) high triangular prism with base measurements equal to those of the sill. Failure in the bottom third of the sill occurred with this additional load.

May 1, 2007

By R. Bruce Ferguson

"IntroductionThe Beaverlodge Operation of Eldorado Nuclear Limited is a uranium property located near the north shore of Lake Athabasca about 7 miles from Uranium City, Saskatchewan.The mill is a 2000 tpd carbonate leach operation producing a high grade yellowcake concentrate.The Lamella Thickener was purchased to replace a 55 foot conventional unit which had deteriorated beyond repair. The cost of the unit was considerably lower than for a conventional unit, installation was much simpler and the unit is much more compact allowing it to be installed in the mill basement and be insulated completely.The unit was sized according to the results of tests performed both by the supplier and Beaverlodge engineering staff. The supplier guaranteed overflow clarities of less than 100 ppm suspended solids. The Lamella thickener was developed by A. Johnson Co. of Stockholm, Sweden, is manufactured under license by Parkson Corporation of Ft. Lauderdale, Florida and is distributed in Canada by A. Johnson Co. of Montreal."

Jan 1, 1975

By Gabka T., R. E. Gregorczyk

Work to improve employees' behavior in Głogów Copper Smelter began in 2009. It has been noted that over 90% of accidents at work are attributable to human reasons. At that time, a series of external workshops was contracted based on exercises conducted by a psychologist trainer with supervisors. Having trained about 300 employees, an observation of employee behavior at workstations was started as part of the control of risk reduction measures. As a result of the above actions, the number of accidents was reduced by half between 2009 and 2017. Currently, internal workshops for communication improvement for behavioral auditors are conducted by the employees of the Smelter. Named: "I observe, react and communicate" and aimed at further mastering the elements of the safety culture in Głogów Copper Smelter. INTRODUCTION KGHM Polska Miedz is an integrated mining and smelting copper producer based in Poland and operates on the international metal market. KGHM, with annual production of over 500 thousand tonnes of copper, holds a middle position in the world ranking of copper producers. At the same time, in Europe it is the largest producer of copper from its own ore deposits, possessing its own integrated production structure, from underground mining operations to final, top-quality product. It is also worth mentioning that KGHM Polska Miedź is one of the largest Polish exporters and, apart from copper, is a significant primary silver producer in the world. The mission of our company, consistent with its strategy, is to produce copper and silver in a safe mode for workers and the environment, with reduced environmental impact. Therefore, "Głogów" Copper Smelter operations are continuously focused on the creation of safe working conditions, and minimizing the negative effects on the environment. The company meets the requirements of an Integrated Management System comprised of the following: Quality Management System ISO 9001:2008 Environment Management System ISO 14001:2004 OHS Management System according to the requirements of BS OHSAS 18001:2007 Being a proud socially responsible company, we are aware that part of an efficient OHS system is to recognize, monitor, prevent, educate and motivate, thus continuously improve working conditions for 2500 employees of Głogów Copper Smelter &Refinery. We clearly communicate that a low accident rate is beneficial for both, staff and the company, and is of utmost importance as a part of our health policy.

Jan 1, 2019

By Kenji Koga

In order to derive the population distribution of gold nanoparticle morphologies as a function of size, highresolution electron microscopic (HREM) observations and structural analyses were done for over 4000 particles (3-18 nm) grown by an inert gas aggregation (IGA) source using helium. To obtain structural features threedimensionally and not to skip high-contrast images, twenty photos were taken for each particle by changing tilting angle of a specimen holder in combination with the through-focus procedure. For the reliable structural determinations, HREM images and their tilting sequences were directly compared with multislice-simulation results for icosahedral, decahedral and face-centered cubic morphologies, and finally the population distribution of each morphology was obtained as a function of size. In the present sample, icosahedral particles were dominantly populated over the whole observed size range and decahedral particles with non-spherical truncated bi-pyramid shape were secondly dominant. Even though a large number of sampling has been done, few crystalline particles were observed.

Oct 1, 2003

By Ivan C. Machado

Jaguar Mining Inc. is implementing a 1.1 Mtpy, 7-year LOM gold project in the Iron Quadrangle (?Quadrilátero Ferrífero?), Brazil. Construction is on schedule and startup is programmed for Q2 2010. Mill feed grade averages 4.43 g/t and LOM gold production is estimated at 800,000 oz. The project entails two sulfide underground mines and three oxide/transition open pit mines. A state-of-the-art flotation/gravity concentration/CIP Plant has been designed based on testwork carried out by internationally recognized Canadian, U.S., and Brazilian laboratories. The mass recovery of the flotation section is only ca 10%, while its gold recovery is about 90%. Therefore, the CIP-ADR Plant will treat only 10% of the solids mass contained in the mill feed, while 90% will be fully cyanide-free material that will be partially used to feed a Backfill Plant. The leached tailings will be conveyed to a rather small tailings dam, whose 20- m3/h supernatant solution will be treated by a new electrolytic technology. The plant design contemplates a High Density Thickener for the cyanide-free rejects exceeding the backfill demand and a Regrinding Section before the Leaching Circuit. The estimated overall metallurgical recovery sits around 92%. This paper focus on the use of modern technologies to reduce costs, risks, and liabilities.

May 1, 2010

By Philip J. Guerney, S. O’ Leary, André R. Laplante

"Concentration of dense mineral phases (s.g. greater than 7) for characterisation of individual particles and mineral grains by electron microscopy is a well established technique for the detection and characterisation of valuable mineral phases. This presentation describes the type of data that can be generated when both the concentration and characterisation steps are carried to higher levels than typical. The concentration step is the gravity recoverable gold (GRG) protocol that has been used for over 100 ore samples. This protocol yields three concentrates that represent three progressive degrees of grinding and liberation. Three ore samples were subjected to the GRG protocol and three size classes of each concentrate were characterised using the mineral liberation analyser (MLA), an automated, EDX-based tool. This presentation briefly presents GRG and MLA technology, and then focuses on the results obtained: photos, images and databank, the latter used to evaluate the extent of particle liberation and particle shape.INTRODUCTIONThe practice of gravity concentration prior to characterization of mineral samples using electron beam microscopy is solidly established. Typically, a dense liquid such as tetrabromoethane (density: 2.97 g/cm3) is used to reject the light phase, typically carbonates and silicates. The heavy phase, mostly sulphides, oxides and precious metals, is then mounted in a polymer matrix and examined using beam microscopy.Both the pre-concentration and the sample preparation/examination steps have seen significant advances over the past ten years, but are not without problems. A major issue of preconcentration is that most dense liquids used are toxic, tetrabromoethane being a prime example. More recently, a dense liquid with little or no toxicity (sodium polytungstate, distributed by Sometu Inc.) has become commercially available, but its use is limited to relatively low s.g. splits around 3 g/cm3. Dense liquids are viscous, and their use is limited to particles coarser than 37 µm, although centrifuge separation can probably lower this limit to around 10 µm. Magnetogravimetric separators can achieve much higher specific density cuts, but upgrading below 100 µm or in the presence of magnetic minerals remains a problem. The use of centrifuge separators such as the 3-in Knelson Concentrator (KC MD3) or the Falcon 4-in SB (SB4) is particularly attractive since these units can easily process large masses (by laboratory standards) and achieve a cut density well above those of dense liquids."

Jan 1, 2003

By B. P. Simser, R. K. Brummer, A. Mortazavi, P. P. Andrieux

"A large-scale panel destress blast was fired at Brunswick mine in the fall of 1999 in order to reduce the ground stresses in a critically important neighbouring mining region. This work, sponsored by the Mining Division of CAMIRO and Brunswick mine, consisted in heavily choke-blasting — and subsequently leaving in place — a massive waste sulphide pillar in the southwest end of the 1000 m level. This paper describes the approach and design methodology used to try to maximize breakage in the rock mass in the area to destress, while minimizing damage to critical infrastructures in the vicinity. The loading operations, as well as the results of the blast — in terms of its field performances, as recorded by near-field blast vibration monitoring equipment, visual postblast assessments and measured impact on the regional stress field — are discussed as well. A brief comparison between the measured stress changes and inelastic numerical modelling of the test site is also presented.Un tir à grande échelle de relâchement des contraintes dans un pilier a été effectué à la mine Brunswick à la fin de l’automne 1999 dans le but de diminuer les contraintes de terrain dans une très importante zone de production adjascente. Ces travaux, financés par la division minière de CAMIRO et la mine Brunswick, consistaient à tirer violemment sans aucune face libre, et à laisser en place, un pilier de sulphures massifs au sud-ouest du niveau 1000 m. Cet article décrit l’approche et la démarche conceptuelle utilisées pour tenter de maximiser les fractures dans le pilier visé, tout en minimisant les dommages collatéraux à des infrastructures critiques se trouvant dans les environs immédiats. Les opérations de chargement des explosifs et les résultats du tir — en termes de ses performances, telles qu’évaluées par de l’équipement de monitoring rapproché des vibrations de tir, d’observations visuelles, et de son impact sur les contraintes de terrain locales — sont également discutés."

Jan 1, 2003

By Deon van Tonder, Chuck Edwards

"Solvent extraction is used in many acid leach uranium circuits to upgrade and purify the uranium bearing solution prior to final product precipitation. A number of strip options are available to recover the uranium from the loaded organic. This paper compares some of these options on the basis of typical capital and operating costs for both the solvent extraction circuit and downstream uranium processing, and also considers other related issues. The aim is to provide an objective comparative assessment of these options that could be used as a qualitative guide in process selection or improvement.INTRODUCTIONIn the 1950s the uranium industry was the first industry to adopt solvent extraction (SX). Since then, the flow sheets have advanced. Notable was the introduction of tertiary amine extractants by General Mills during the late 1950s and 1960s (Mackenzie, 1997; Mackenzie, 2005), which is still today considered ‘state of the art’ technology. Initially solvent extraction was done in combination with ion-exchange, such as in the Eluex flow sheet, followed later by the adoption of direct solvent extraction from pregnant leach solution (PLS). From a strip-precipitation perspective ammonia strip followed by ammonium diuranate precipitation was widely adopted as the norm in the uranium industry. More recently alternative strip systems have been receiving increasing attention due to the environmental, health and safety issues associated with ammonia and the resulting calcined uranium oxide product. This paper explores some of these alternative options in comparison with the ammonia route.It is important to acknowledge that each operation is unique, and therefore the information and philosophy outlined in this paper serve to provide a general guide that can be potentially applied and adapted to any site or project."

Jan 1, 2013

By Robert E. McIvor

"“Classification System Efficiency (CSE)” is a powerful, emerging tool that can be used to increase grinding circuit efficiency. It is defined as the percentage of the ball mill energy being used to grind target, oversize particles. The discovery, validation and current use of CSE, including how it was manipulated, are described through seven plant case studies. These resulted in efficiency improvements ranging from 3 to 30 percent, along with major reductions in over-grinding. The achievable CSE for any given circuit is described. This paper demonstrates both how, and how much, every plant can benefit from increasing grinding circuit CSE.DEFINITIONS: BALL MILL CIRCUIT “CLASSIFICATION SYSTEM EFFICIENCY (CSE)”, “EFFECTIVE MILL GRINDING POWER”: “WASTED/OVER-GRINDING MILL POWER”The closed ball mill circuit is shown in Figure 1. The extreme importance of the circulating load ratio in determining circuit productivity was demonstrated by Davis (1925) and re-published by Guadin (1939), as shown in Figure 2. The circuit production rate increases with increased circulating load ratio, rapidly so at first and continuing to increase more gradually with higher and higher values of circulating load ratio.The underlying cause of this relationship was seen when comparing the ball mill feed and product size distributions from two different ball mill circuits, one with a low circulating load ratio, and one with a high circulating load ratio (Figure 3). While the F80’s and P80’s of these two circuits were close to the same, the mill feed and discharge size distributions were quite different. The ball mill in the circuit with the higher circulating load ratio contained a substantially greater fraction of material coarser than the target P80, as indicated by the respective mill feed and discharge size distributions. This fraction represents the fraction of the mill power being expended on “coarse” (in this case, plus P80 size) material, or the circuit “classification system efficiency.” The “effective mill grinding power” is the total mill power multiplied by the CSE. The compliment of CSE, the remaining fraction of “fines” in the mill, is the fraction of the mill power being wasted, and spent on over-grinding of material already finer than the circuit target product size. This is the “wasted/over-grinding mill power”"

Jan 1, 2013

By Xing Jin, Dan Graffi, Glenn MacPherson, Dan Rioux

"The complexity of a modern flotation circuit makes it susceptible to disturbances such as changes in feed, ore mineralogy, equipment degradation, poor measurements and faulty instruments. Good measurements and a robust control system are critical to create and maintain a stable and optimum flotation process.This paper focuses on the development and implementation of process control applications in the flotation circuits at Xstrata Nickel’s Strathcona Mill ( referred to as the mill hereafter ) in Sudbury, Ontario. Following the path of ‘stabilize-improve-optimize’, basic controls to stabilize process variables such as flotation cell pulp level, air and reagent addition rates, cleaning-column feed and wash-water rates have been established. Factors such as best practice in pulp level and valve position measurement, feedforward control and the application of an appropriate control philosophy, have contributed to the significant reduction in process variability. For instance, standard deviation reduction of 79% for the Ni impurity in the column Cu concentrate grade was experienced and is shown. The variability reduction of the flotation circuits’ key process-variables paves the way to further improve and optimize flotation performance. A grams-per-metal unit reagent addition control scheme has been improved upon, particularly for different operating scenarios and better robustness. In addition, following significant stabilization of the primary controls and columns feedrates, Cu/Ni separation cleaning-column bias-control (cascaded to the wash-water rate) and hold-up control (cascaded to air flowrate) have been developed and tested. This strategy – from stabilization to optimization - is expected to achieve a more consistent control of final concentrate grades and improve recoveries.INTRODUCTIONFlotation is considered the most important and value-added process in the milling metallurgical plant and is still undergoing continuous evolution to treat greater tonnage and different ores (Wills, 2006). Starting over three decades ago, with the advent of on-line slurry content analysis devices, flotation automatic control has received persistent interest and a large number of applications have been reported (Thwaites, 1983, 1986 ; Mckee, 1991). Bergh and Yianatos (2011) reviewed different aspects of process control in flotation circuits and have evaluated the applicability of model predictive control to the process. Mckee (1991) analyzed the difficulty in developing lasting/robust process control applications for flotation circuits and stated that the path of stabilization-refinement-optimization would more likely lead to successful flotation circuit process control. Best practice on column process control was discussed by Bouchard, etc. where a multi-layered approach was proposed, provided that the measurement of column process variables ( i.e. bias, froth depth, hold-up, etc. ) are measured reliably (Bouchard & Thwaites, 2008). Wills (2006) stated that the best practice for flotation automatic control starts with fulfilling basic control objectives, such as stabilized flotation cell level, air flow, pH, reagent flow etc., before considering more advanced, or even optimal, control of metallurgical targets, which are more closely linked to economic performance."

Jan 1, 2013

By Kevan J. R. Ford, Chris A. Fleming, Robert D. Henderson

"Kinross Gold Corporation’s Maricunga mine in Chile presents an ideal opportunity to apply the SART process to a heap leach operation. Given increasing levels of cyanide complexed copper in current pregnant solutions from Maricunga heaps (over 300 ppm Cu), there is a need to reduce these levels and decrease cyanide consumption and cost. Additionally, a means of disposing of this copper is required, preferably as a saleable product. The well published SART process applied to gold-copper cyanide solutions was selected as it allows rapid precipitation of cyanide soluble copper as a relatively pure copper sulphide. The process also allows effective recovery and recycle of cyanide back to the heap leach operation.This paper reviews the SART process chemistry and presents a summary of SART bench-scale and pilot plant testwork completed by Kinross. Key design parameters and engineering aspects of the proposed plant at Maricunga are discussed. SART plant operating costs and net revenue analysis are included and illustrate the compelling economics of installing a SART process plant. INTRODUCTIONMaricunga OperationCompañia Minera Maricunga (CMM), fully owned by Kinross Gold Corporation, operates the Maricunga mine (formerly Refugio) which is located 120 km due east of the city of Copiapó at an elevation of 4,200m above sea level in the Andes mountains of northern Chile. Figure 1 shows a map of the location of the Refugio mine relative to other gold and copper mines in the region."

Jan 1, 2008

By E. C. Grunsky, B. W. Smee

"The development of low-cost, rapid multielement analytical techniques has generated large geochemical databases in many exploration programs. When a sampling program consists of several thousand samples, the resulting data matrix is enormous and effective interpretation using all of the elements individually becomes burdensome. However, the application of multivariate statistical techniques can extract geochemical patterns related to the underlying geology, weathering, alteration and mineralization. Imaging the results over topography enhances the interpretation of these patterns. Examples of this approach are shown from mineral exploration programs in Canada and Mexico. IntroductionThere has been a dramatic change in the effectiveness of using geochemical survey data in the past ten years. This is mostly due to:• lower cost of geochemical analysis;• lower detection limits;• new methods of multi-element analysis;• a marked decrease in the turnaround time;and• the intelligent use of computers in presenting geochemical data.Geochemical surveys commonly have two objectives: locating abnormal concentrations of ore-forming or pathfinder elements and characterizing the underlying host lithologies. Geochemical surveys often employ a wide range of sample media that may typically include whole rock lithogeochemistry, various soil horizons, till and basal till sampling, stream sediments, lake sediments, and various forms of weathered regolith. Each of these sample media will exhibit a unique element distribution that must be factored in the interpretation phase of a geochemical survey study. This can become a cumbersome process if univariate data handling methods are employed."

Jan 1, 2003

By K. Meyer

"INTRODUCTIONThe David Bell Mine Concentrator started production in April 1985. A staff of twenty-seven people operate and maintain the concentrator. The crew is grouped into the following main areas.16 Operators6 Assaying/Metallurgy/Refining/Clerical4 Maintenance people2 SupervisionOperating highlights of the following unit processes will be discussed in detail:Screening and ThickeningPre-aeration and CyanidationCarbon-In-Pulp Gold AdsorptionCarbon Handling andGold RecoveryFor a complete description of the concentrator, refer to the papers by: (1) C.V. Sibbald, Teck-Corona's Hemlo Mill, October 1984, (2) R.A. Ford, The David Bell Mine at Hemlo, From Exploration to Production, November 1987. For operating details of the grinding circuit and effluent treatment plant refer to papers by: (3) T.G. Smith, SAG Mill Experience at The David Bell Mine, October 1988, ( 4) AN. Veltmeyer, The Effluent Treatment Plant of The David Bell Mine, January 1989.TRASH AND CARBON SCREENSTrash ScreenThe vibrating trash screen is inclined at 5 degrees and is clad with a 28 mesh stainless steel cloth which is changed monthly during the SAG mill liner replacement/inspection shut down. Other screen openings and configurations have been tried and the screen has been by-passed to change the cloth ""on the fly"". These attempts resulted in fibres (usually wood) to report to #1 Carbon-In-Pulp (CIP) tank, where the fibres are trapped in the CIP launder screens, and downstream carbon handling screens causing serious blinding problems. The trash screen in a Carbon-In-Pulp (CIP) or Carbon-In-Leach (CIL) gold mill removes fibres before they:are reground in the ball millsaturate with gold bearing leach solutionplug launder screens in CIP or CIL tanksplug carbon circuit pipe screenstherefore the trash screen is best placed ahead of the thickener."

Jan 1, 1989

By G. Stokreef, B. R. Davis, M. Kadiyski, Alvear Montenegro, H-P. Loock, V. Montenegro

An optical probe for burner monitoring in copper flash smelting, first developed at the University of Concepcion, is being industrially tested in a collaboration between Kingston Process Metallurgy, Aurubis AG, and Queen’s University. The sensor uses fibre-optics and optical emission spectroscopy to analyze the light emitted from combusting particles in the furnace reaction shaft. Information that can be extracted from the emission spectrum includes the temperature and brightness of the flame, as well as emission lines or bands from excited atomic and/or molecular species. Laboratory proof of concept testing of the sensor was first completed in a continuously fed drop tube reactor using O2/S stoichiometric ratios between 0.8–4.0. These O2/S stoichiometries capture the industrial operating condition, which is typically less than 1. The results from lab testing justified a plant trial of the optical probe, which was done in the Aurubis Hamburg flash furnace in September 2018. From this trial, approximately 31 hours of spectral data were collected and synchronized with furnace operating data. The results from both drop tower test work and the plant trial are discussed with implications for process monitoring in the commercial furnace. INTRODUCTION Flash furnace smelting is a continuous feed, batch tap, pyrometallurgical process. It is used to treat copper sulphide concentrates and small amounts of secondary materials, such as dust generated by the process. O2 enriched air and the concentrate blend are fed into the furnace reaction shaft through the concentrate burner. As the particles fall through the reaction shaft, they heat up and ignite, causing rapid, exothermic reactions that oxidize the iron sulphide, some copper sulphide and impurities in the feed. Reacted particles fall into the settler of the furnace, melt and separate into a matte and slag, while the SO2 enriched off-gas is carried out of the furnace for heat recovery and H2SO4 production. Operation of the furnace is achieved by adjusting a limited number of control variables. The main variables are the blast feed rate, blast oxygen enrichment, SiO2 flux feed rate and CH4 combustion rate (CH4 is used when the chemical energy of the concentrate is low) all measured relative to a set feed throughput. (Davenport & Partelpoeg, 1987; Davenport, King, Schlesinger & Biswas, 2002) The batch tapping nature of flash furnaces makes operation difficult because these control variables impact each other, and product quality can only be measured when matte and slag are tapped from the furnace. This means that operation of a furnace is based on feedback control from matte and slag assays. Because of the time-delay associated with understanding product quality, there is interest in using technology to monitor the combustion reactions that happen in the furnace reaction shaft.

Jan 1, 2019

By Todd Smith, Brigitte Lacouture, Greg Anderson, David Lin

"The lead and zinc flotation circuits at Red Dog Mine are preceded by a preflotation circuit which recovers naturally-floating organic carbon contained in the ore. Organic carbon is a potential contaminant in the lead concentrate and is detrimental to lead-zinc selectivity. Prior to 2007, the Red Dog preflotation circuit consisted of a single stage bank of tank cells which floated the organic carbon. The preflotation concentrate was discarded directly to tailings, however, this stream contained significant amounts of lead and zinc. Zinc loss to preflotation ranged from 2% to 6%, relative to the zinc in the mill feed and was proportional to the amount of organic carbon in the ore. The main mechanism of the zinc loss was entrainment.Pilot plant and modeling testwork were conducted to examine the use of a Jameson Cell to clean the preflotation concentrate. Results indicated that up to 90% of the zinc deporting to preflotation concentrate could be returned to the flotation circuit for recovery. The installation of a 5.4 m Ø Jameson Cell with 18 downcomers was initiated in June 2006. The new preflotation cleaning circuit was commissioned in March 2007. Conservatively, preflotation cleaning has resulted in zinc and lead absolute recovery gains of 1.0% and 1.5%, respectively. The $9.1M project has a payback period of approximately 1 year at current metal prices.INTRODUCTIONRed Dog Preflotation CircuitRed Dog Mine is located above the Arctic Circle in northwest Alaska. It is the world’s largest zinc concentrate producer with a production rate of more than 1.0M t/yr. Red Dog is operated by Teck Cominco Alaska Incorporated under an operating agreement with the Northwest Alaska Native Association (NANA). Due to the remote location of the mine, it is accessible only by air, or seasonally, by ocean-going barges.The Red Dog deposit is a rich sedimentary exhalative (sedex) zinc-lead-silver deposit. The major sulphides, in decreasing order of abundance, are sphalerite, pyrite, galena and marcasite. Due to the complex nature of the ore body, run-of-mine ore is blended in stockpiles before being crushed and processed through the concentrator. The average mill feed grade for 2006 was 6.1% lead, 20.6% zinc, 8.0% iron and 0.67 % organic carbon."

Jan 1, 2008

By Ernest Baafi

A simulation model RoadSIM using the ARENA modelling system has been developed to evaluate roadway development options for a given development panel configuration. The RoadSIM simulation system has provisions for variability/randomness in operations including cutting and loading at the face, tramming and discharge of coal to the boot end and availability of equipment. The modelling system provides a means for assessing the operational limitations of roadway development practices at a particular coalmine. It is a ?what if? tool that allows a range of equipment, configurations and operating practices to be assessed in terms of achievable advance rates and equipment utilisation. Output from the system is in the form of a dynamic visualisation as well as summary reports and detailed logs of operations over time.

Oct 1, 2009

By Jom Kresta

Fundamental changes in the Bitumen Production process at Syncrude have led to the integration of Mining and Extraction operations. Successful operation of the integrated process requires the coordinated effort of several business units. Hence, decision-making has become increasingly more complex and better tools are required. IO2 is a collaborative effort to develop a proof-of-concept prototype of a distributed decision-support system for integrated short-term production and maintenance planning with fleet allocation and dispatching. The prototype includes three main modules (planning, dispatch, and maintenance), a shared database, and a simulation module. At this stage, this prototype is used to plan and operate a simulated mining operation. It is used to demonstrate the viability of the chosen systems architecture and algorithms, as well as the information flows and interactions necessary for improving the overall performance of the integrated operation. While the problem is demonstrated using Syncrude?s site, the methodology is applicable to most integrated resource allocation problems.

May 1, 2002