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By Ramón Alanís, Filiberto Orrante, Andrea Festa, Baldomero Gutiérrez, Fernando Cornejo

"SGS implemented two rules-based fuzzy logic expert applications on two grinding circuits operated by Peñoles Group in Mexico. Both expert systems are based on control strategies that push against process constraints to improve throughput. Based on proven methodologies, the projects also required some new approaches that led to permanent changes to the mill control strategy.This paper provides descriptions of the implementation, operation and performance of both expert systems. It also reviews how improved production rates were achieved through the use of a common set of expert technology tools. An overview of the resulting control strategies implemented on the two circuits is presented. The paper also discusses the identification of the process constraints within each circuit and how these constraints are used within the expert systems.INTRODUCTIONMexico-based mining company Peñoles Group and the Advanced Systems group at SGS, formally known as MinnovEX Technologies Inc., collaborated on the implementation of two expert systems in two grinding plants, both located in Northern Mexico.The primary objective of the expert systems was to increase throughput whilst still maintaining the cyclone overflow product size within an acceptable range. The secondary objective was to achieve a high level of utilisation of the expert technology.In order to achieve these objectives, SGS proposed a proven methodology which leveraged the existing operating and technical expertise at site through the client’s involvement in the design and implementation stages. The in-house operating and technical expertise of SGS was also brought to the project and implemented with the client’s approval at all stages. At both sites the final acceptance was defined upon meeting both process and utilization parameters.The development and deployment of rules-based fuzzy logic applications has matured as a technology and consequently, clear definition of process states and their place in the logic structure to control a given circuit are now transferable. The key to the robustness of the control logic depends on selection and tuning rules for maintaining stability and optimizing a given circuit. Application integrators need to have a standardized approach for timely integration and deployment; a critical component to avoid the common critiques that expert applications are idiosyncratic and difficult to maintain."

Jan 1, 2009

By Euler De Souza

This paper presents a study conducted to assess sillmat behaviour during undercut mining and to provide a comprehensive understanding of the effects of arching and sillmat thickness on stability. The design study investigated the effects of such parameters as stope width and height, closure strains, orebody geometry and inclination, wall roughness, fill properties and cure time on the stability of cemented sillmat during undercut mining. Arching effects have been quantified based on centrifuge modeling studies for the different mining conditions. Observations have indicated that the degree of arching is a function of stope geometry, wall roughness, fill cohesion, and wall closure. Arching effects increased with decreasing stope width, increasing backfill cohesion and frictional resistance, increasing wall roughness and with wall closure.

May 1, 2002

By Gregory A. Johnson

Operations and Maintenance departments have long had an adversarial relationship. The widespread evolution and adoption of modern management techniques such as Reliability Centered Maintenance (RCM) and Lean Production however has driven interest in working co-operatively to optimize overall plant performance. Mining and minerals operations have long adopted RCM in maintenance, and are now adopting Lean throughout the organization. Modern management initiatives like these explicitly call for co-operation between the two disciplines of maintenance and production and many advances have been made in the realms of people and methodology. One area that has lagged behind in supporting these developments however is information systems. Enterprise Asset Management (EAM) systems in maintenance and newer Manufacturing Execution Systems (MES) in operations have not been truly integrated in the way needed. Complicated plants, different software architectures, continually changing conditions and many variables have lead to systems problems which have contributed to the maintenance/operations divide. Master data synchronization (the ?plant tree?) and integrated reporting of real-time data with transactional data are just two of the issues that are being solved by new approaches in information technology including web services and service orientated architectures. New technologies are coming on-stream to enable the final ?bridging of the gap?.

Feb 1, 2008

By A. C. T. Bigg

"The mineral potential of the Nanisivik area was discovered as far back as 1910 when a prospector of the Geological Survey of Canada, on an expedition under Captain J. G.Bernier, recorded a deposit of pyrite with minor sphalerite and galena. An outcrop of the present orebody was discovered by Texas Gulf Company in 1957. Subsequent drilling outlined the orebody consisting of 6,000,000 tonnes of ore containing 13 % Zinc and 1.5 % Lead. The orebody appears to have been formed by the filling of a limestone cavern with sulphides. The sulphide minerals consist of pyrite, sphalerite and galena. The limestone bedrock is mostly dolomite with some calcite and magnesite. A cutoff grade of about 6% Zinc has been calculated.In 1972 Mineral Resources International Limited took an option on the property. Upon completion of the feasibility study by Watts, Griffiths and McOuat, the then new independent project management group of Strathcona Mineral Services Ltd. were engaged to develop the project through the financing, construction and operating phases. Strathcona Mineral Services still manage the project from their head office in Toronto and through the Mine Manager and Department Superintendents at the Mine site. The interest for the project is presently split five ways: Mineral Resources International Ltd. 53.5 %, Government of Canada 18 %, Metallgesellschaft A.G. of Germany 11.25 %, Billiton B. V. of Holland 11.25 % and Texas Gulf Co. 6 %."

Jan 1, 1980

By Turgut Yalcin

"Recent years have seen a resurgence of interest in flotation cell design, and one of the areas where attention is being focused is flotation in centrifugal fields which aims at increasing the flotation rates by forced bubble-particle contact.A new cycloflotation device was developed at Laurentian University and tested on the nickel ore of Falconbridge Limited in Sudbury. In comparison with conventional flotation, cycloflotation yielded at least seven times faster flotation rates in terms of the mass of solids floated per unit time per unit flotation volume, while producing concentrate grades similar to those of conventional flotation. These results, which were obtained with a bench-scale ""cyclofloat cell,"" suggest that cycloflotation has the potential of setting a new direction in flotation technology.IntroductionFroth flotation is no doubt the dominant separation technique in the mineral processing industry. Since its inception early in this century, much research effort has been and is still being expended on this process. Until recent years, emphasis seems to have been placed on the chemical aspects of flotation, but there is now an increased awareness for the need to improve flotation machine performance and more and more attention is being directed towards this area. In a 1982 article on ""Flotation Machines"" (Young 1982) it is stated that "" ... by now the design of the machines used would have reached a high level of perfection, ... In fact, this is not the case ... "".The process of flotation in a flotation device may be considered to take place in several distinct stages as follows:"

Jan 1, 1994

By Jan E. Nesset, Julie Fournier, Jorge Torrealba, Colin Hardie

"Gas dispersion studies have been used to benchmark and optimize plant flotation performance for more than a decade, although this technology is not as widely in use as it likely should be based on the significant improvements that have been reported. Part of the reason may be a general lack of awareness within the industry of just what these improvements have been. This paper reviews a number of the reported case studies, groups them into categories of improvement, and draws some general conclusions. The paper will be of interest to plant engineers and technology providers seeking new approaches and tools for improving their own and clients’ processes.INTRODUCTIONThe sector of flotation hydrodynamics that is now known as gas dispersion technology, and the corresponding terminology, had its beginnings in the 1980’s and early 1990’s in the laboratories of McGill University where the students of Prof. J.A. Finch and Dr. C. Gomez conducted studies of gas holdup, superficial gas rate and water recovery on laboratory flotation columns (Laplante et al., 1983; Xu et al., 1991;, Banisi and Finch, 1994; Finch et al., 1999; Nesset, 2011). Sensors were developed for gas holdup (eg), gas rate (Jg) and bubble size (Db) distribution (Tavera et al., 1996: Finch et al., 1999; Dahlke et al., 2001; Chen at al., 2001; Hernandez-Aguilar et al, 2002, 2005). The sensor measurements were rapidly adapted for use in mechanical flotation machines in plant environments (Gomez and Finch, 2002; Gomez et al., 2003; Cooper et al, 2004; Torrealba-Vargas et al, 2004; Nesset et al., 2007). Somewhat parallel developments were being conducted by Gorain and colleagues at the University of Queensland’s JKMRC on pilot and industrial flotation machines using the McGill approach but utilizing alternate sensor designs for eg, Jg and Db (Gorain et al., 1997, 1999; Schwarz and Alexander, 2006) to link flotation kinetics to bubble surface area flux (Sb). Early industrial applications were those led by the university teams from McGill (Canada), the JKMRC (Australia) and the University of Santa Maria (Chile) at plants in North and South America, Australia, South Africa, Asia and Europe. Industrial organizations that brought the technology on-board in the early 2000’s included Teck Resources (then Teck Cominco), COREM, Vale (then Inco), Anglo American Platinum. Several of the major flotation cell manufacturers also purchased the McGill bubble viewer technology for their own equipment studies. The sensors have continued to evolve with multiple and continuous measurement of Jg (Torrealba-Vargas and Finch, 2006, Bartolacci et al., 2008), gas holdup by acoustic means (O’Keefe, 2007) and a combined Jg-Db device called the Anglo Bubble Sizer (Harbort and Schwarz, 2010). A review of the gas dispersion technology use and development have been provided by Gomez and Finch (2002), Harbort and Schwarz (2010) and Nesset (2010)."

Jan 1, 2015

By P. Walford, C. Mealin, D. Good

"The geology of the Ore Fault Ni-Cu deposit has been reinterpreted in the light of recent studies of the geology of the Neoarchean Bird River Sill Complex and the occurrence of economic Ni-Cu and Zn-Cu-Ag mineralization. The Ni-Cu sulfides are hosted by the lower of two parallel NNW-trending and moderately W-dipping mafic-ultramafic intrusions related to the Bird River Sill Complex. The bod¬ies intruded a bimodal volcanic suite consisting of weakly deformed mafic flows and felsic pyroclastic rocks. The mafic volcanic rocks are geochemically related to the MORB-type rocks of the Lamprey Falls Formation, and the felsic volcanic rocks are related to arc-type rocks of the Peterson Creek Formation. The original pyroxene- and olivine-dominated mineralogy of the sills has been replaced by variable ser¬pentine-amphibole-talc-carbonate assemblages.The Ni-Cu sulfide assemblage exhibits textures and geochemical signatures typical of orthomagmatic sulfide mineralization. The sulfide minerals are associated with cumulate layers of magnetic ferrochromite that range in thickness from a few to tens of centimeters. A later event of Zn-Cu-Ag sulfide mineralization associated with quartz veining and garnet-chlorite alteration along a fault that strikes north, dips vertically, and cuts all rock types. The mineralized fault is cut by the NE-trending Peterson Creek shear zone. Where the Ni-Cu and Zn-Cu-Ag mineralized zones intersect, remnant magmatic features such as amphibolite or cumulate ferrochromite bands occur within quartz veins or local chlorite alteration. The mixed zones contain a very unusual polymetallic assemblage of Ni, Cu, Zn, Ag, and platinum group elements (PGE)."

Jan 1, 2009

By Robert Gannicott

??A mining company without the burden of operating a mine ??Management focused on marketing a high-quality, run-of-mine range of Canadian diamonds ??Robust revenue stream ??Specialist diamond knowledge ??Canadian exploration and development expertise ??BUT ??Single asset revenue base from depleting ore reserve ??Limited influence on production plans

Apr 1, 2005

By Elmer Stewart, Richard May

"The Central Mukur deposit was discovered by the Semipalatinsk Geological Exploration Expedition (GEE) during detailed searches from 1977 to 1980. Andas Altyn Ltd., a Kazakhstanian gold mining company acquired the property and commenced mining in 1995. In 1998, Andas-Altyn Ltd. became a wholly owned subsidiary of Eurasia Gold Corporation.The Central Mukur gold project covers a linear series of parallel, discontinuous zones of near surface oxide gold mineralization that covers a distance of 7 kilometers and extends past the property boundaries. The oxide gold mineralization is a result of the regional oxidization of a primary sulfide gold mineralization emplaced in a series of shallow dipping thrust faults. Resources as calculated by the GEE are 3.45 mt at an average grade of 1.84 gmt Au in the C1 +C2 category and 7.52 mt at an average grade of 1.80 gmt Au in the P1 category. The Central Mukur Gold Heap Leach Mine consists of an open pit, heap leach pads, and an ion exchange resin gold recovery plant. Limited gold production (<2,500 ounces/year) has been achieved over the past three years leaching run of mine oxide gold mineralization. Gold recovery utiling cyanide to dissolve the Au and ionic resin technology to recover the Au for the leachate is approximately 60%. Loaded resin is shipped to a treatment plant at Almaty where the gold is stripped from the resin, refined and sold.This paper will describe the geology, mining, and processing of the Central Mukur ore. In addition, it will describe what it is like doing business in Kazakhstan and the transition from a Soviet style operation to a more western style operation.INTRODUCTIONThe Central Mukur Mine is owned and operated by Andas-Altyn Ltd. a Kazakhstanian gold mining company located in northeast Kazakhstan. Andas-Altyn is a wholly owned subsidiary of Eurasia Gold Corp., a Canadian public company listed on the Alberta Stock Exchange. The Central Mukur mine consists of a small open pit, and a heap leach operation that utilizes ion exchange resin to recover gold from pregnant solutions. In addition to the Central Mukur mine, Eurasia also owns the Myaly heap leach gold project which is also operated by Andas- Altyn Ltd."

Jan 1, 1999

"Mineral separation by exploiting the differences in mineral or metal specific gravities (sg) has been used since antiquity. In the modern era, this is most commonly seen in the recovery of gold by the use of centrifugal concentrators and the separation of coal (low sg) from waste rock (high sg) using heavy media cyclones and jigs. Other metals, notably oxides of tin and tungsten, are successfully recovered using some combination of jigs, spirals and shaking tables. However, many conventional gravity separation systems are limited to fairly coarse (>1 mm) to medium (>100 micron) particle separations due to the limitations of the gravitational separation forces in conventional equipment.Many of the high specific gravity minerals of interest are friable (e.g. cassiterite, wolframite, etc.) and excessive fines are generated in the grinding/comminution circuits which cannot be recovered with conventional equipment and may be lost directly to the tailings stream. Recent developments in centrifugal gravity separation equipment specifically designed for fine or ultra-fine particle separation and recovery have resulted in heavy mineral particle recoveries as fine as 10-20 microns. Ongoing research work has also identified the benefit of closed-circuit, multi-stage gravity recovery circuits using some combination of centrifugal concentrators and conventional equipment (tables, spirals, flotation, etc.) which can substantially increase overall plant recovery and final concentrate grade.This paper will provide details of the evolution of non-fluidized bed gravity concentrators for high sg mineral recoveries, correlate laboratory scale development work with plant results to confirm scale-up, and show how recent flowsheet developments have contributed to significantly improved plant performance.IntroductionGravity concentration is one of the oldest and most cost effective metal and/or mineral recovery systems, ranging from the classic hand panning of alluvial gold, through to the large scale production of a wide range of metals and minerals, including gold, silver, PGMs, black sands, coal and iron oxides. Conventional gravity recovery systems, comprised of some combination of sluices, spirals, jigs and shaking tables have limited application in fine particle (i.e. <100 microns) recovery, or where there are limited differences in particle specific gravities (sg), e.g. the separation of high sg, high value metal oxides (e.g. those of tin, tantalum or tungsten), from medium sg, lower value metal sulfides such as pyrite and pyrrhotite. These unit operations tend to have limited capacity, and while double and triple turn spirals and multi-deck tables have been developed, extensive floor space is often required in order to process the tonnages incorporated in the modern mineral processing plant."

Jan 1, 2017

By Y. Bai, J. J. Liu, D. Q. Li, S. Z. Liu, X. T. Wang

"This paper presents the results of an industrial test using 8 t/d of Baotou concentrate (50% REO) of a clean metallurgical process, which includes: 1. Roasting with H2SO4 at low temperature (220~260 0C) in a batch roasting furnace followed by water leaching to obtain a leach liquor as feed with a yield of >95% RE and Th, recovering F as fluoride, producing a leach residue amounting to 1/3 of an equivalent high temperature residue and containing <0.03% Th and radioactivity < 3×104 Bq/kg compared to the normal high temperature residue containing 0.2-0.3% Th and 1×105 Bq/kg. 2. Separating Th with N1923 and extracting RE by P507 has been completed in mixer-settlers. Test results indicate that the ThO2 product has a purity of > 95% with a yield of 99%, and the RE has a yield of >95%, in which ThO2/REO <5×10-6, and that P507 loaded RE connect straight with separating RE using P507-HCl system. 3. Treatment and multipurpose use of "three wastes" (water, gas and solids) are discussed in some detail."

Jan 1, 2014

The #3 Shaft at Brunswick Mine, Bathurst, New Brunswick, Canada, intersects a soft graphite zone just below the 3400 Level. Ground movement within this zone causes the concrete liner of the shaft to be deflected towards the shaft?s interior, affecting the steel framework of the conveyance. In some areas, the clearance between the cage and the liner has been reduced to less than 2 cm, which is a concern. An innovative surface-mounted extensometer was designed in 2008 to monitor potential movements of the shaft?s liner. Four such novel extensometers were installed in the shaft for the surveillance of a particularly critical 3.0m by 5.5m area. This article describes the approach taken to instrument the shaft, the principle of the new extensometer, as well as the performance of the instrumentation following its installation.

May 1, 2009

By Jan E. Nesset, Phillip J. Mackey

"Studies have shown that there is a correlation between commissioning and start-up time, i.e. time to reach full plant design capacity, and the degree of innovation and technical/engineering uncertainty in the project design. The paper describes the types of start-up curves for plants according to the level of technology or uncertainty in the process design. The need to properly describe and understand the commissioning and start-up time is examined using these curves and the importance on project success is highlighted. A number of case histories of recent mining and metallurgical projects are also reviewed. Finally, the paper reviews how to better assess the level of start-up uncertainty associated with a project and makes suggestions for decreasing the commissioning time due to technological risk.INTRODUCTIOThe start-up of a new mining and metallurgical facility, a much anticipated event, is a critical step in the life of such a project. Achieving a successful start-up and reaching the design capacity on-time requires careful planning, a thorough understanding of the key technological and engineering components involved and a well-trained and adequatelystaffed start-up crew. In this paper, some of the aspects related to start-up of a mining/metallurgical project will be explored, and in particular, the impact of the technology component will be examined. In order to illustrate this, a number of case histories based on recent mining and metallurgical projects will be discussed. Ways of assessing and understanding the uncertainty associated with technological issues related to start-up of a mining and metallurgical plant will also be examined.The history on mining and metallurgy is full of success stories of great mines and mills that are now considered “company makers” (well known examples of such successes include the Horne mine for Noranda which had a 1 year start-up in 1926-27, the Dome mine for Placer Dome, the Grasberg deposit for FMI in Indonesia). Less well documented are specific studies relating to plant start-ups and what constitutes a success or a failure, however there are a few notable references in the literature and these will be reviewed."

Jan 1, 2003

By Dave Bulled, Chris Bennett, Glenn Kosick, Glenn Dobby

"Mining companies around the world are embracing geometallurgical modeling at a rapid rate, as senior executives realize that inputs must be properly measured if the output is to be managed effectively. Geometallurgical modeling is used to scientifically manage risk in project evaluation, for plant design and production forecasting, and optimization of production planning and mineral processing/metallurgical unit operations. The technology also provides a solid foundation for implementing broad corporate strategies with respect to intelligent asset utilization and metal sales. Over the past five years, MinnovEX Technologies Inc. has been actively engaged in developing, promoting and applying geometallurgical modeling technology for major mining companies around the world. This paper describes the methodology for successfully applying the technology for the unit operations of comminution and flotation in the mining industry.INTRODUCTIONGeometallurgical modeling (referred hereon as geomet modeling), in theory, can be applied to its full potential on all unit operations in mineral processing; however, this paper will concentrate on two of the largest unit operations, namely comminution and flotation, where the technology is actually being practiced by many large mining companies. For concept studies and prefeasibility studies, aspects of geometallurgical technology are regularly applied but in a less rigorous manner than for final feasibility studies where justification for funds is sought. This paper will focus on the final feasibility stage of a project and on existing operations or planned expansions, where the full power of geometallurgical technology is brought to bear in a cost effective manner.One of the unique aspects of geomet modeling, when used to its potential, is the ability to design plants, and forecast and plan production with a quantifiable degree of precision, something that was unattainable in the past. This means that when new comminution and flotation plants are designed, the mining companies and financial institutions involved in the project can measure the precision of the design and therefore better understand and manage project risk. It means that for existing and new operations, metal sales personnel can carry out their sales strategies with a much better understanding of the degree of error associated with production forecasts of concentrate/metal and quality of concentrates. For mine and mill managers, geomet modeling allows the effect of the mine plan on the downstream processes to be quantified; thereby allowing the mine plan to be recast in a more optimized manner. Finally, existing concentrator personnel can optimize their unit operations based on a more definitive understanding"

Jan 1, 2004

By H. McSorley

"I note that many of you are involved in the production of zinc, lead and copper concentrates and metal, which I am the most familiar with among the non-ferrous metals. This afternoon, I will describe briefly the responsibilities of a commercial manager within a mining/metallurgical company, the basic framework of a non-ferrous metals concentrate agreement and lastly, a brief discussion of the copper, zinc and lead concentrate and metal markets.I hope this talk will contribute to a better understanding of the business between all of us and look forward to a discussion after the presentation.First of all, I work for Noranda Sales, which is the marketing and sales agent for Noranda Minerals' three operating units: Noranda Copper, Noranda Zinc and Mining Corporation. In addition, Noranda Sales acts for other mining companies in the marketing of their raw materials and metals. Noranda Sales is responsible for procuring all raw materials for Noranda's metallurgical plants, such as the Copper Group's Forne and Gaspe smelters, as well as the sale of surplus concentrates and by-products and metal products. In addition, Noranda Sales trades metals and concentrates and owns a metal brokerage business, Rudolf Wolff, a founding member of the London Metal Exchange. It does $3 billion of business in 60 countries, exporting some 80% of Noranda Minerals' output to the world.What are the responsibilities of commercial management in resource marketing to the mine and metal producers?Resource marketing and commercial administration involves assistance in establishing exploration priorities, contributing to feasibility studies, pre-production planning, product promotion and realization of income for many properties and metallurgical plants through completion of supply and sale agreements with other companie"

Jan 1, 1988

By Terry A. Kirk

"This paper describes Derrick High Frequency Vibrating Screens and their process performance in grinding circuit applications. The benefits of screen sizing in closed circuit grinding are illustrated by case histories from a wide spectrum of mineral industries.INTRODUCTIONHigh capacity, reliable wet screening equipment is increasingly in demand by the mining and allied industries for separations finer than 1/.7 5mm (I/ mesh). The continuing search for improved energy efficiency and reduced steel consumption in comminution has Jed to greater scrutiny of every aspect of circuit design and operation, including the classifier efficiency (selectivity) function.Derrick Manufacturing Corporation has been developing high frequency screening machines designed specifically for grinding circuit applications since 1973. Successful installations are currently operating in iron ore, copper, coal, uranium, phosphate and other extractive industries."

Jan 1, 1984

By Y. Faitakis

In the mining industry, maintenance is a key priority and a major expense. As mining equipment is large in scale, high in cost, and difficult to tow, it is key to maintain equipment on a timely basis. Breakdown in -40°C or away from a maintenance station can cause great costs in repair as well as lost production. It has often been quoted that about 5% of the North American production is lost every year due to unscheduled downtime. About one-third of the downtime is attributable to equipment failures. From this fact alone, it is evident that proper equipment maintenance can add tremendous value to the bottom line. As organizations and equipment become more sophisticated, maintenance expectations begin to evolve. This evolution can be traced through three generations: The first generation (1940?1950): A ?fix it when it broke? attitude prevailed during that time, mostly because the industry was not highly automated. The second generation (1950?1980): Automation and mechanization of the industry increased. The industry now was dependent on machines performing the majority of the work. Preventive maintenance (overhauls at fixed intervals) appeared as the first maintenance practice. Maintenance costs started to rise rapidly. The third generation (1980?): Assets become more complex. Failure modes are better understood and computerized maintenance methods are becoming mainstream. Condition-based maintenance (CBM) starts to gain ground as a cost-effective alternative, replacing the fixed interval overhauls. As corporations amalgamate and market places are becoming more complex, multi-functional teams become responsible for maintenance. At the beginning of the third generation, maintenance organizations began embracing technology to provide efficiencies in maintenance management. A strong push was made to transition from reactive maintenance to proactive maintenance. At the forefront of this push is condition-based maintenance.

Jan 1, 2004

By D. J. McLaws

"Recent innovations in metal smelting technology utilize continuous oxygen-enriched smelting and converting processes which are capable of producing off-gases containing up to 60% SO2 or more. Other SO2 recovery processes, involving solvent absorption and steam or vacuum regeneration, can produce off-gases with SO2 concentrations nearing 100%.Processing of these high-concentration SO2 off-gases in conventional sulfuric acid plants can cause excessively high catalyst bed temperatures and poor SO2 conversion. In order to avoid these problems, a conventional acid plant design must dilute these high SO2 process gasses with dilution air in order to provide the required oxygen to effectively convert the SO2 and provide a heat sink (via the inert N2) such that the exothermic reaction, SO2 + ½ O2 ???SO3, does not exceed the temperature limit of the catalyst or the converter vessel.MECS, Inc. (MECS) has proven that a high SO2 feed gas design can be a viable option which can increase energy recovery, reduce energy consumption and potentially reduce capital costs."

Jan 1, 2014

"This paper reviews the chemistry involved in the recovery of gold from cyanide solution with anion-exchange resins, and also discusses the most critical aspects of the engineering of an effective resin-in-pulp (RIP) process. As far as the chemistry is concerned, the conclusions reached by a great many researchers, as well as the performance of the only operating RIP plant in the Western World, at the Golden Jubilee Mine in South Africa, support the view that the process is technically viable and, in many cases, could prove to be more attractive economically than alternative processes such as zinc cementation and carbon-in-pulp (CIP). On the engineering side, there is still a need for further development before larger scale ( > 50,000 tpm) RIP plants can be designed, built and operated with confidence. However, the experiences gained during nearly 3 years of operation of the Golden Jublee RIP plant indicate that the process can be engineered with confidence for smaller operations ( < 50,000 tpm), and this will probably be the scope of application of the first-generation RIP plants. INTRODUCTIONThe use of anion-exchange resins in gold processing has, for a number of years, been proposed as an alternative to more conventional processes such as zinc cementation and carbon adsorption, and detailed research programs that have been carried out at a number of laboratories have demonstrated the technical viability of the process. (Burstall et al, 1953, Davison et al., 1960, Tataru, 1973, Laskorin et al. 1978, Hosking, 1984, Riveros and Cooper, 1987 and Palmer et al., 1988)The main incentive for this work was the fact that resins have several characteristics that are quite different from carbon, which make them potentially more attractive substrates for the recovery of gold. The following are examples: -"

Jan 1, 1991

By Y. Faitakis, G. J. Powley, C. Mackenzie

"In the mining industry, maintenance is a key priority and a major expense. As mining equipment is large in scale, high in cost, and difficult to tow, it is key to maintain equipment on a timely basis. Breakdown in -40°C or away from a maintenance station can cause great costs in repair as well as lost production.It has often been quoted that about 5% of the North American production is lost every year due to unscheduled downtime. About onethird of the downtime is attributable to equipment failures. From this fact alone, it is evident that proper equipment maintenance can add tremendous value to the bottom line. As organizations and equipment become more sophisticated, maintenance expectations begin to evolve. This evolution can be traced through three generations:The first generation (1940–1950): A “fix it when it broke” attitude prevailed during that time, mostly because the industry was not highly automated.The second generation (1950–1980): Automation and mechanization of the industry increased. The industry now was dependent on machines performing the majority of the work. Preventive maintenance (overhauls at fixed intervals) appeared as the first maintenance practice. Maintenance costs started to rise rapidly.The third generation (1980–): Assets become more complex. Failure modes are better understood and computerized maintenance methods are becoming mainstream. Condition-based maintenance (CBM) starts to gain ground as a cost-effective alternative, replacing the fixed interval overhauls. As corporations amalgamate and market places are becoming more complex multi-functional teams become responsible for maintenance.At the beginning of the third generation, maintenance organizations began embracing technology to provide efficiencies in maintenance management. A strong push was made to transition from reactive maintenance to proactive maintenance. At the forefront of this push is condition-based maintenance."

Jan 1, 2004