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By A. J. Hyett

Due to the ongoing revolution in electronics and communications more cost-effective geotechnical instruments can be manufactured using digital technology. This new generation of digital instruments have embedded microcontrollers that provide highly accurate and reliable measurement of geotechnical behaviour in real world units that can be immediately interpreted. Digital measurements can be transmitted across existing mine-wide wireless communication networks, interfaced directly with infra-red enabled PDA?s or PC?s, and parsed to memory by low-cost data-loggers.

Oct 1, 2004

By R. Grimard, M. Gamache, L. -P. Bigras, P. Cohen

This paper describes a real-time fleet management system for an undergroun mine. Dispatching, routing and scheduling are handled simultaneously, taking into account the mine status, operational constraints and vehicle location information. Each assignment decision takes into account the traffic on the road segments of the mine network, whether road segments are bi-directional or uni-directional, and ensures that each LHD (load-haul-dump) vehicle arrives at loading and dumping points with the correct orientation. Such a system can be used either as a simulation tool for strategic planning or as a real-time managing and optimizing system for operations. In the simulation mode, the system can accurately estimate the impact on productivity of decisions such as the development of waiting areas (bays, sidings), or the addition (elimination) of vehicles to the fleet in operation. When used for real-time dispatching, routing and scheduling of vehicles, the system can optimize production with respect to various assignment criteria such as cycle-time minimization or deviation from a target production plan.

Jan 1, 2004

By A. R. Barnes, N. O. Lotter

Recoverable economic copper sulphide minerals such as chalcopyrite, bornite, chalcocite and covellite often occur together in varying proportions in the major copper-bearing ores, and have individual flotation requirements and characteristics. Pyrite also occurs in these ores to varying extents as the sulphide gangue, and is problematic because of its natural tendency to float quickly and easily. In a bulk sulphide float, selectivity against pyrite is desirable, particularly if it does not host other paymetals such as gold or silver. At the same time it is a requirement to float all of the copper sulphides despite their electrochemical differences. The electrochemistry and semiconductor properties of these minerals are reviewed, together with implications for flotation with and without collector addition. Mixed collector systems for the improved flotation of these sulphides are proposed as a solution. The use of xanthate and dithiophosphate in the collector suite allows the co-existence of dixanthogen and free dithiophosphate radical because the latter has a higher redox potential requirement than xanthate to oxidise to the dithiolate. Because some of these minerals require dixanthogen, and others, free thiolate, to generate surface hydrophobicity, a bulk flotation of all the species becomes possible in the overlapping area of Eh and pH between the two dithiolate equilibrium lines on the Pourbaix diagram. The arsenic-signature copper minerals are added to the study, since many copper operations encounter arsenic as a penalty element in the saleable concentrate. It is shown that the addition of arsenic to the copper and iron sulphides alters the semiconductor and electrochemistry properties, and in turn, its flotation characteristics. The degree of mineral association and liberation between these minerals can be a complicating factor due to textural associations, and should also be considered in the process as a next step.

Jan 1, 2016

By Peter Dunn

London Mining Plc. is developing an iron ore project in Sierra Leone. The Marampa mine is a brownfield development effort, having been operated by others since the 1930?s until low iron ore prices forced closure. Peak production of the prior operations was approximately 2.5 Mt/a in the 1960?s. Following civil war In Sierra Leone, London Mining obtained the mining license in 2006 and commenced activity to redevelop the Marampa mining and processing operations. There are two ore deposits of interest for development as well as a resource comprised of tailings from previous operations. Phase 1 will be the mining of the tailings resource with a 1.8 Mt/a plant producing 66 per cent Fe sinter feed, expandable to 3.6 Mtpa. The first phase is currently under construction with start-up expected in the third quarter of 2011. Phase 2 will include development of the two ore deposits. These deposits are weathered secondary ore and the main primary ore resource. Phase 2 is currently under prefeasibility study and targets a final 16 Mt/a concentrate production in 2016. Outotec partnered with London Mining on testing efforts to develop the magnetic separation flowsheet using SLon VPHGMS machines to process the Marampa material. This paper explains the flowsheet development process for the weathered and primary ores commencing with sample characterization and detailed parametric investigations to evaluate SLon performance. The final flowsheet configuration is explained, including expected circuit recoveries and concentrate quality, clearly demonstrating the performance of the SLon VPHGMS circuit in iron ore tailings treatment applications.

May 1, 2011

By J. Kazakoff

"The success of gold recovery at the Jolu gold mill depends on many variables. The most important ones are the people, the ore body, plant design parameters, equipment selection and cost control. This paper will briefly hiqhlight the above, the main focus, however will be on the gravity gold circuit.The gravity circuit requires judicious operator attention in order to operate properly. In return the circuit gives immediate visual results for mill peopleIntroductionThe development of the Jolu property to the production stage was carried out quickly, efficiently and economically. The property became a gold producer ahead of schedule and under budget.The Jolu property is a joint venture between International Mahogany Corp., a 70% partner, and Corona Corporation, a 30% partner. Corona Corporation operates the Jolu Gold Mine, located 140 kilometers north of LaRonge and 520 kilometers north of Saskatoon."

Jan 1, 1990

By Joseph J. Mgumbwa

Pillars are any structures left between two or more underground openings. The stability of pillars is normally considered to depend on shape (defined by width to height ratio), rock mass strength, extraction ratio, in situ stresses and the gross structural features (i.e. joints, contacts, faults etc). Recent experience has shown that pillar stability is also controlled by the relative orientation of the orebody with respect to the in situ principal stress. In inclined orebodies, pillars are loaded in compression and shear, thus creating unsymmetrical stress distribution. Failure mechanisms of these pillars are little known. This paper investigates the failure mechanisms of pillars under shear loading. Two dimensional elastic numerical modeling was used to examine the behavior of pillars in different orebody inclinations relative to the major farfield stress orientation. First, the paper reviews pillar design approaches including the empirical pillar design chart and uses numerical modeling to investigate the effect of the major farfield stress orientation on pillar stability. It is concluded that the empirical pillar design chart be used with caution, and that for orebodies under shear loading mine planning and design should take this into consideration since such geometrical orebody/stress relations put mine structures at higher risk of instability.

Oct 1, 2010

By P. G. Claridge, R. A. Tenbergen

"Pipe Open Pit ore is delivered by rail to the Thompson Mill at a rate of 34,000 tons per week. Ore is milled at a rate of 220 tons per hour.Characteristics of the serpentinised peridotite host rock are such that significant deviations from hitherto experienced milling practice became a necessity because of coagulation of the gangue upon cominution.Extensive development work was done in the grinding and classification circuits to better understand the ore characteristics and optimize operating parameters and the use of available equipment. This work ultimately resulted in the change from 30 to 20-inch diameter cyclones.Coagulation of the ore slurry and the characterstics of the sulfide minerals necessitated an ""unconventional approach"" in processing as compared with the beneficiation of Thompson Mine ore.Recent changes in ore characteristics led to testing of antistatic agents to reduce tailing losses."

Jan 1, 1975

By J. R. Goode

"The Las Cristinas deposit contains about 10.2 million ounces of gold at a grade of 1.3 g/t. The deposit comprises a layer of fully oxidized saprolite (SAPO), a layer of sulphide-enriched saprolite (SAPS), carbonate leached bedrock (CLB) and carbonate stable or un-leached bedrock (CSB). Gold occurs at about the same level in all lithological groups. The bedrock units contain minor amounts of copper (about 0.1%) as chalcopyrite, while SAPO contains virtually no copper it having been leached and deposited in the SAPS zone.A previous owner started investigation of the Las Cristinas deposit in Venezuela in 1991. Over the next seven years, 1174 holes with a total length of 159 km were drilled, extensive metallurgical testwork, including pilot plant operations, were conducted and feasibility studies were completed. Construction was started in 1997 and again in 1999 but was suspended.Crystallex has been producing gold in Venezuela since the early 1990’s. In 1997, Crystallex acquired Inversora Mael which had held two of the claims to the Las Cristinas concessions since 1986. In September 2002, Crystallex entered into a definitive agreement with the Corporación Venezolana de Guayana, (CVG), to develop the Las Cristinas deposit.An extensive program of studies and testwork was started in early 2003 to determine an optimum development plan for Las Cristinas. Mine Development Associates, SNC–Lavalin Engineers and Constructors, SGS Lakefield Research Limited, J.R. Goode and Associates, and Professor A. Laplante at McGill University acted as the main contractors.Because of the potential value of by-product copper, earlier flowsheets used carbon-in-leach for SAPO, but processed all other ore types by flotation to produce a gold-copper concentrate with cyanide leaching of cleaner tailings to maximize gold recovery. Cyanide recovery was necessitated by the high copper content of the leach feed. Initial studies of available data by Crystallex revealed that direct leaching of all ore types would provide about 11% more gold recovery than the previously selected flotation route with reduced capital and operating costs.Bench and pilot scale studies have confirmed that a SAG-ball mill-gravity-CIL route is very effective for all ore types and will give about 89% gold recovery. This paper describes the recent testwork, discusses the proposed plant design, and presents economic data."

Jan 1, 2004

By S. Haggarty

"Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Milling capacity is 3,400 SDT /Day with an average feed grade of 0.080 Oz Au/Ton. Gold processing involves three stage grinding including tertiary pebble milling, two stage cyanide leaching and filtering and Merrill-Crowe zinc precipitation.A summary of process improvements required to increase milling capacity above the initial design tonnage of 2, 700 SDT /Day are described -Installation of a 42"" x 65"" Allis Chalmers Gyratory crusher replacing a 42"" x 48"" Traylor jaw crusher.Installation of polyurethane screen panels replacing woven wire cloths on an 8' x 20 ft triple deck screen.Installation of a hopper clarifier to reduce filtrate turbidity.Automated control of solution balancing and effluent treatment circuits.INTRODUCTIONThis paper describes mining and milling practices at the Nickel Plate Mine and details post start-up process modifications which were required to attain design tonnage.Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Mining capacity from the open pit is approximately 32,000 TPD with an average waste/ore ratio of 8.4:1.Milling capacity is 3,400 SOT/Day, above initial design tonnage of 2,700 SOT/Day. Feed grade averages 0.08 Oz Au per ton yielding 85,000 troy ounces of gold per year."

Jan 1, 1991

By Gregg S. Hill, Bert J. Huls

"This paper on coarse particle recovery (CPR) summarizes a process to capture coarse particles that are not recoverable by regular flotation. Several porphyry copper operations in the world operate analogous circuits that recover non-floated copper from tailings; however, the case presented here is unique in that extensive underlying test work has allowed us to elucidate some fundamental principles behind recovery enhancement. This paper discusses an overview of the flow sheet that is proposed to Minera Escondida Ltda., the nature of copper in the feed to the CPR circuit, and the various unit operations within the recovery circuit. Details of the technology behind each unit operation will be presented in later publications.INTRODUCTIONSince 1996 BHPBilliton and MEL (Minera Escondida Ltda.) have developed a process to recover copper from coarse particles in the rougher tailings. Copper recovery from fresh tailings is not new. Several operations in Chile, such as Chuquicamata, El Teniente (AMEC, 2003), Mantos Blancos and others have operated various forms of tailings circuits. Both Chuquicamata and El Teniente practice cascade flotation scalping off froth containing fine copper particles after allowing sufficient retention time, air inducement and, sometimes, additional reagent addition. Chuquicamata tailings are not segregated but floated in sequential cascade and conventional large cell arrangements. At the Valle Central operation of El Teniente a coarse fraction of mill tailings is ground and floated, with the rejects recombined with fine tailings and subjected to cascade flotation through a sequence of concrete launders as the tailings flow towards their final deposition area. Mantos Blancos cyclone the rougher tailings and blend the underflow with scavenger concentrate from elsewhere in the principal circuit prior to flotation in Wemco Cells. Kemess in BC, Canada operates a 160 m3 Outokumpu cell to reduce the tailings sulfur content (Rasmussen, et.al, 2004)."

Jan 1, 2005

By Douglas M. Smith, G. A. Maki

"The initial development of the massive potash deposits of the prairie evaporite formation took place over a decade ending in 1970. The potash mining and refining facility near Rocanvi11e, Saskatchewan was the 1ast of ten mines to come into production during that era. This operation, known as Sylvite of Canada Ltd., was designed to produce 1. 2 million short tons per year of KCl product in granular, coarse, standard and special standard grades.In 1977 the parent company, Hudson Bay Mining and Smelting, sold the Sylvite property to the Potash Corporation of Saskatchewan. Shortly thereafter PCS slated its new Rocanville Division for a two phase program of expansion. The first phase, completed in the spring of 1979, was relatively small, involving mill debottlenecking and additional equipment in the compaction circuit and the product and ore storage areas. The second phase was a major undertaking which included additional mining equipment and a new 300 STPH milling circuit. This work was completed during the fall of 1981 and has increased the Rocanville Division's nameplate capacity to two million STPY.Thickening equipment operating in the Saskatchewan potash industry is generally situated within the main refinery building or a separate insulated and heated structure due to the harsh winter climate and the need to closely control plant brine temperatures to ensure good flotation circuit performance. Since these thickeners process large volumes of slurries, conventional basin type designs tend to be large, ranging up to 150 feet in diameter or more. As part of the general effort to minimize capital costs, the potash industry has begun investigating the use of alternate high capacity, compact thickener designs. In this regard, PCS Rocanville undertook a program in 1978 to evaluate a Lamella™ Thickener and one other type of 'High Rate' thickener* as alternatives to a conventional design for the phase two expansion project."

Jan 1, 1983

By Filipe Beretta

This study investigates geophysical logging capacity to predict coal quality. It was analyzed for possible correlation, some parameters determined via laboratory analysis of coal against results for the same parameter derived from wireline logs recorded by a geophysical probe. These probes detect variations in some rock physical properties, such as their natural gamma ray emissions and electrical resistivity. Results showed a strong correlation between natural gamma and ash content, establishing a linear model to estimate ash content from geophysical logging data with a low estimation error (less than 5%). Besides, results showed that there is no correlation between sulphur content or volatile matter and resistivity, neither with natural gamma of the rocks. Ash content derived from gamma ray values can be used as secondary information to evaluate coal quality during resources estimation, using methods such as soft indicator kriging. The methodology is illustrated using a case study at a coal deposit in south of Brazil.

Oct 1, 2009

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

"RésuméDans la première partie de cet article on discute Ie mode d'écail age aetueJJement en usage dans des mines souterraines. Par la suite, on presente la problematique d'écaillage à l’aide de barres conventionnelles et on discute les plus recénts développements des outils d'ecaillage portatifs et mécanisés ainsi que les techniques de détection des roches branlantes. Plus tard, on analyse la tâche d'écaillage avec des barres conventionnelles. Dans les chapitres qui suivent on présente un concept d'un outil d'écaillage portatif et mécanisé développe à l'Université Laval, ainsi que les résultats des essais de cet outil, effectués dans quelques mines au Québec. On constate que Ie nouvel outil d'écaillage démontre un potentieJ intéressant tant au niveau de l'effort requis pour effectuer la tâche d'écaillage que de la sécurité des mineurs.On conclut que l’application de cet outil fera un pas important sur Ia voie d'amélioration des conditions de travail dans les exploitations souterraines, tout en assuarnt une qualité accrue de l'écaillage.AbstractThe first part of this paper discusses the type of scaling operations presently in use in underground mines and derma; a scaling factor which is expressed as the:: area necessary to scale to extract one ton of ore. Subsequently, the problems associated with conventional scaling methods are discussed as well as recent developments in mechanized hand-held scaling devices and methods of loose detection. The elements of the scaling process are further analyzed. In subsequent sections of this paper, the conception and design of a mechanized scaling device, developed at Universite Laval is described. The results of field tests conducted in Quebec hard rock mines are presented. The experimental findings show that the mechanized hand-held scaling device shows great potential in improving the productivity and safety of underground mining operations."

Jan 1, 1995

By R. Grant, C. Bazin

"Brunswick Mining has investigated grinding media optimization for the purpose of improving the flotation feed and regrind product size distributions to enhance metal recoveries. This paper presents the findings of on-going testing of various sizes and shapes of grinding media. Plant observations combined with estimated breakage rates demonstrate the importance of appropriate selection of media sizes on the milling operation.IntroductionBrunswick Mining and Smelting is located near Bathurst, New Brunswick, and operates one of the world's largest lead and zinc mines. The ore mineralogy and processing flowsheet have been described elsewhere (Petruk and Schnarr, 1981; Shannon et 01., 1993). Despite the 25 years' milling experience, there has been considerable disagreement as to the required grind size (Grant et 01., 1991). Since 1964, fineness of the flotation feed ranged from 60% to 80% passing 400 mesh (37 um) and averaged slightly above 71% in 1992. Results from mineralogical analysis (Petruk and Schnarr, 1981), laboratory and pilot plant experiments, as well as plant sampling (Grant et al., 1991; Hendriks and Ounpuu, 1985; Shannon et al., 1993) indicate that improved metal recoveries can be achieved by an increase in the fineness of grind, and more specifically by maximizing the amount of material in the 15 urn to 25 um range.This paper shows the results obtained so far from the evaluation of the effect of grinding media size and shape on grinding mill efficiency. The problem of finding optimum grinding media size, shape and composition has been recogrtized since the early 19405. The main criterion for the selection of media size is the size of the material to be ground (Bond, 1958). Although several relationships have been proposed to assist in the selection of grinding media size, none of them are entirely satisfactory (Wills, 1988). Other approaches using the breakage rates and process simulators were developed to help in the selection of grinding media size (Austin et al., 1976; Lo and Herbst, 1986; Concha et 01., 1992; Samskog et al., 1990; Martinovic et al., 1990). Although considerable effort was put into the analysis of grinding media size, very little information is available on the effect of grinding media shape (Norman and Decker, 1985, p. 3C-4). Norris (1952), Kelsall et al. (1973) and Herbst and Lo (1989) have shown that balls are more efficient than other shapes of grinding media including truncated cones and cubes."

Jan 1, 1994

"A simple approach to optimizing the performance of an operating carbon in pulp (CIP) or carbon in leach (CIL) plant is presented. It is possible to reproduce the performance of an operating CIP or CIL plant in the laboratory, in small scale batch tests in which the rates of gold leaching and carbon adsorption are determined, coupled with mathematical models that translate the batch kinetic data into predicted steady state profiles of gold in solution and on the carbon across multi-stage adsorption circuits.Once the performance of the commercial plant has been mimicked by the model, the plant operating parameters can be varied systematically in the model, and the likely response of the plant to the stepwise change can be determined. In this way it is possible to inexpensively optimize the design of both greenfields CIP or CIL circuits and plant expansions, or optimize the operating parameters of an existing plant, with no disruption to plant operations and no economic risk to the mining company.This approach has been adopted by IAMGOLD Corporation, to the immediate benefit of two of their existing gold operations. The methodology adopted and the results achieved are presented.INTRODUCTIONThe carbon in pulp (CIP) and carbon in leach (CIL) processes became firmly established in the gold mining industry in the 1980s, initially in South Africa and Australia, from where they spread rapidly to all the gold producing regions of the world. The percentage of annual global gold production by activated carbon-based processes grew from zero in the 1970s to almost 70% by the turn of the century, which represented a phenomenal rate of acceptance of a new technology by a traditionally conservative industry. The main reason for this rapid acceptance of the new technology was the fact that the first few large plants built in South Africa convincingly demonstrated better gold recoveries than the traditional filtration/Merrill Crowe process, with lower capital and operating costs. And as the plants developed an operating track record over their first few years of life, they proved to be remarkably robust mechanically, and highly tolerant of plant upsets, changes in feed composition and solution phase contaminants that had caused problems in Merrill Crowe plants."

Jan 1, 2011

By Renaud Adams, Vladimir Salatic

"The El Mochito Mine located in Honduras, Central America, has produced lead, zinc and silver in concentrates since the 1950s. The paper discusses changes made in both lead and zinc circuits to reduce costs while maintaining production during the recent period of low metal prices.The intent of this paper is to show that sometimes thinking “outside the box” is beneficial for progress. Also, in striving for better metallurgical results we should not forget the basics of flotation. Sometimes the latest trends may not be applicable to the ore we are treating and may not meet the operating cost constraints.A major beneficial impact on El Mochito metallurgy was achieved when the overall grind was coarsened, eliminating the significant percentage of slimes. Switching from two parallel twostage grinding circuits to one circuit with three-stage series grinding has resulted in a significant reduction in power and steel consumption. With minor layout/reagent modifications, both lead and zinc circuits gained not only in retention time but as well in producing better grade products.Of course, the challenges are still there; they exist and only with the full support of operational data collection and metallurgical laboratory investigation success can come. That is why, we as professionals, can never stop in trying to make the most of what we have.INTRODUCTIONThe El Mochito Mine is owned by American Pacific Honduras S.A. de C.V. (AMPAC) a subsidiary of Breakwater Resources Ltd. Of Toronto, Canada. The mine is located in western Honduras, approximately 220 kilometers northwest of the capital city, Tegucigalpa and 90 kilometers south of the country’s second largest city, San Pedro Sula. The mine began operating in 1948 and to date has produced more than 19 million tonnes grading 240 g/t Ag, 3.5% Pb and 7.4% Zn. Production in 2005 was 700,190 tonnes grading 87 g/t Ag, 1.85% Pb and 6.61% Zn.Decreasing metal content in the ore followed by the lowest zinc price on the market in the last 15 years (see Figure 1) has reduced the cash flow and endangered to stop the operation."

Jan 1, 2007

By Doug Smith, Ross MacFarlane

"The Star Lake Mill was commissioned by Cameco (formerly Saskatchewan Mining Development Corporation) in 1986 to process a small high grade gold deposit in a remote location of Northern Saskatchewan. The lean approach to the 200 t. p. d. CIP mill to minimize capital and operating costs employs a number of unique features which are described along with highlights from the initial two years of operation.1.0 INTRODUCTIONThe Star Lake Mine is located 520 kilometers north of the City of Saskatoon (Fig. l) with the nearest population centre in La Ronge 130 km to the south. Gold showings were first discovered in the area in the 1940's with the Star Lake ""21 Zone"" ore body discovered in 1983. The Star Lake Mine started operations in 1986 becoming the first primary gold producer in Saskatchewan in over 40 years. The mine is operated by Cameco (formerly SMOC) with 50\ ownership in a joint venture with starrex Mining Corporation (35\) and Uranerz Exploration and Mining (15%).The limited reserves coupled with the remote location and the price of gold ($300-$350 u.s./oz) at the time the project feasibility was being assessed required a lean approach to make the short term operation successful. This paper describes the approach taken in the design and construction of the Star Lake Mill and describes the mill operation with highlights of the initial two years of operation."

Jan 1, 1989

By John G. Peacey, Leoncio Sevilla G., Ford. Kevan J. R., Erling Villalobos C.

"Kinross Gold Corporation’s Mantos de Oro (MDO) gold/silver mine in northern Chile currently processes 15,000 tpd of oxide ores through a mill, whole ore cyanide leach plant followed by a Merrill-Crowe refinery. With the expected depletion of these oxide ores in a few years a new sulphide mineral deposit, Ladera-Farellón has been identified to potentially replace existing ore reserves. The deposit contains approximately 0.5g/t Au, 6g/t Ag and 0.5% Cu. The principal sulphide mineral in the deposit is enargite (Cu3AsS4) which hosts the majority of gold and silver and the copper. Direct cyanidation testwork has shown the sulphide mineral is refractory with a low gold recovery of 36% and silver recovery of 45%. Oxidation of the sulphides is required to liberate gold and silver and allow recovery of copper as an important pay-metal. Therefore, at MDO a new metallurgical process route with oxidation as a pretreatment step is required for viable treatment of such new sulphide mineralized material with acceptable recoveries of pay-metals.Analysis of flowsheet options was completed based on bench-scale and pilot scale metallurgical testwork as well as with reference to existing studies and operations. The process options investigated assume concentration of sulphides by flotation, followed by either pressure oxidation, bacteriological oxidation or roasting. Preliminary evaluation of flowsheet options focused on process risk, operability, technology availability and the economics of the project with emphasis on use of the existing metallurgical plant to reduce capital cost. Operating costs for each process option were also included in the relative analysis.The challenges of treatment of MDO sulphides, principally enargite and pyrite for recovery of gold, silver and copper center on fixation of arsenic and sulphur capture with environmentally acceptable disposal of residue tailings. This environmental focus was included in the process option selection and comparative analysis.This paper presents a review of the process options considered and highlights comparative advantages/disadvantages of each process with associated environmental issues. Preliminary conclusions are drawn on roasting as a potentially favorable process option for the treatment of MDO sulphides."

Jan 1, 2009

By R. O. Burt

"Gravity Concentration, the oldest form of Mineral Processing, remains of major importance to the Industry. Current applications of Gravity Concentration are briefly examined.The Paper details one approach to the development of a Gravity Concentration Plant, from laboratory and mineralogical techniques, through Pilot Plant testing, where applicable, to the actual design of the plant.INTRODUCTIONGravity Concentration, once the major method of concentrating minerals has, for much of the twentieth century been regarded, like the dodo bird, as obsolete. However, in more recent years it is enjoying something of a renaissance, and is once again being treated as a useful, economic alternative in the Mineral Processing Engineers' arsenal.An indication of the broad application of gravity concentration is the variety of minerals presently recovered. A list is given in Table 1; this list is not exhaustive."

Jan 1, 1984