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By L. Archambeault

This paper describes preliminary research on the application of Markov Decision Processes (MDP) to Real Option Valuation (ROV) and the optimisation of mine scheduling. The MDP framework is a novel approach to option valuation and scheduling in mining operations. A learning agent is introduced into the valuation process of an open pit, where prices and block ore grades have probabilistic values. The prices are modelled using a mean reverting diffusion process and the block grades using sequential Gaussian simulation. The agent is asked to learn which production parameters should be used in order to maximise the overall value of the project. The introduction of the agent permits a real option approach to mine valuation, such that the value associated with the robustness of a design to uncertainty can be measured. A simulated example is used in which there are ten blocks to be extracted under conditions of grade and price uncertainty. Using policy iteration, an optimal policy is generated and the value of production options is found. The potential financial gains from applying MDPs to mine valuation and optimisation are substantial and warrant further investigation.

Jan 1, 2007

By M. Ayhan

Drums of a modern longwall shearer are manufactured to include various constructional features conveying extracted material onto the face conveyor as efficiently as possible. Designing a drum with a conical shell or with reduced vane length, consequently with a stepper vane angle, is the most widely employed method in an attempt to increase loading efficiency. This study compares loading performances of two such drums, one having a conical shell with modified loading vanes, the other with a cylindrical shell with reduced vane length. Firstly, the loading performances of drums are predicted and the maximum haulage rate attainable with the drums are calculated. Then the performances of drum are compared by long-term comprehensive underground trials with coal shearers under similar conditions during the production operation of Park Termik Cayirhan coalmine in Turkey. Although higher loading performance is predicted for cylindrical drums, the in situ trials point out that Globoid drums have a slightly higher loading performance than cylindrical drums. Furthermore, the relationship between operational variables, i.e. extraction height, sumping depth, haulage rate and in situ loading performance, were investigated statistically on the basis of data gathered during the underground trials. Keywords: longwall mining, shearer drums, loading performance.

Jan 1, 2006

By David J. Blackwell

The challenge; to design production facilities and in particular separation equipment which have the ability to deal effectively with the ever changing composition of well fluids, over the life time of the field in which it is operating, ensuring maximum uptime of the asset coupled with consistently effective separation. Design engineers are, however, continually confronted with a dilemma when selecting materials of construction for Oil/Gas separation equipment, since they are generally obliged to select an acceptable material of construction, based on ?predicted? operating conditions, at the lowest acceptable cost. Consequently many designs are somewhat basic and do not take into account the constantly varying dynamics of the well fluids being released into the separator. As oil fields mature, oil companies endeavour to maximize revenue by maintaining oil and gas throughputs. This often results in an associated increase in water and sand volumes and, in order to maintain efficient separation, an increase in operational temperature and pressure; subjecting the equipment to operational conditions for which it was never designed. In reality, therefore, the limitations and constraints placed upon new construction design often result in Maintenance Engineers having to solve the ensuing problems in difficult ?in-field? environments. Should refurbishment or upgrade be required then the status of the platform and that of the vessel during shutdown will dictate how this is achieved. Hotwork on the vessel is generally not preferred due to the requirement for post weld heat treatment and re-classification of the pressure vessel, not to mention the added risk in terms of safety. Unfortunately, until recently, there have been few alternatives to conventional ?hotwork? repair and protection systems, especially since the performance of cold curing polymer based repair and coating systems, for use in oil and gas process equipment, has, until recently, been limited by their resistance to temperature and pressure in immersed conditions. In line with the continued development of high temperature / high pressure oil and gas fields however, recent breakthroughs in polymer technology can now offer both repair and protection solutions which are able to function effectively at temperatures up to 180°C in immersed conditions combined with resistance to the destructive forces of explosive decompression from pressures in excess of 90 bar. This paper will look at recent work that has been undertaken to determine the suitability of modern polymer based repair and protection systems as an alternative to hotwork; thus enabling newly designed and upgraded internals to be cold bonded into position and further protected with temperature resistant coatings, in order to minimize the downtime of the asset and further to protect the vessel internals from the Erosive Corrosive environment.

Jan 1, 2006

By S-L. Weeber

Ash fusion temperature is the temperature at which the mineral matter in coal begins to soften, flow and fuse. It is an important parameter relating to coal utilization. Optimum ash fusion temperatures derived from coal in the Witbank Coalfield region are approximately 1400°C, and higher, although temperatures above1300°C may be deemed acceptable. This study attempted to determine which factors, mineralogical or inorganic-chemical, influence variations in the ash fusion temperatures in certain coals. Coal was sampled from the Number 2 coal seam at opencast and underground workings at New Clydesdale Colliery, Witbank Coalfield, South Africa. The samples represented known low and high ash fusion temperature coal. Analyses performed included proximate analyses, calorific value determination, percentage sulphur, ash fusion temperatures, ash analyses (composition of ash), X-ray diffraction, scanning electron microscopy and petrographic studies. Results show that although a complex relationship exists between ash fusion temperature and the various geological and coal parameters, some positive correlative results were obtained. These indicate a possible relationship between low ash fusion temperatures and i) finer size fractions, ii) an increase in iron content present in the form of pyrite and iii) the form in which pyrite is present, namely cleats. High ash fusion temperatures tend to correlate with i) the absence of pyrite or ii) pyrite present as framboids.

Jan 1, 2000

By E. J. M. Jahnsen, I. Jauhari, T. Badrujaman, F. A. Stober, B. O. Wasmund, L. R. Nelson, T. Miraza, J. M. A. Geldenhuis, A. Taofik Hidyat

The role of dedicated operational support in the ramp-up and stabilisation of the FeNi-II furnace for ferro-nickel production at PT Antam?s smelter located in Pomalaa, Indonesia is described. The furnace was uprated to 32MW capability in a rebuild performed in 2005. This primarily involved installing a larger transformer, coupled with adoption of HATCH water-cooled copper plate, waffle and flanker coolers with integrated metal and slag tapblocks, HATCH air-cooled copper fin lower sidewall cooling and HATCH vertical sidewall binding system ? ?holddowns?. Following a smooth commissioning period, the progress in attaining the preliminary ramp-up target load of 24MW is described. This initial target was set by Antam, subject to some prevailing smelter equipment constraints, particularly kiln capacity. Stabilisation of the furnace operation is discussed, together with some of the specific commissioning and operational challenges surmounted by the joint Antam-HATCH team. These included: ?Mastering furnace integrity monitoring and operation with copper coolers, especially metal tapblock planned maintenance and repair strategies; ?Transition from traditional ?immersed electrode? to ?brush-arc? mode of operation approaching as closely as possible to the productive ?shielded-arc? mode of operation within existing equipment constraints; ?Reductant selection and control issues; ?Utilising the sophisticated furnace monitoring to provide detailed indication and warning of potentially destructive furnace upset conditions such as Si reversion and CO boils.

Jan 1, 2007

By G. J. van Tonder

The use of Molecular Recognition Technology (MRT), a highly selective separation technology using specifically designed ligands (such as macrocycles), has been demonstrated to be an effective treatment process for removal of several ions that are commonly found in many hydrometallurgical circuits as well as in environ-mental treatment operations. Ions removed by MRT include base, heavy and transition metals, precious metals, halides, and alkali/alkaline earths. A MRT pilot plant run was conducted at Zincor to demonstrate the cobalt/nickel purification of zinc electrolyte, and to recover saleable pure cobalt/nickel sulphate solution. The MRT process holds various advantages, which include the elimination of a catalyst such as arsenic trioxide, conventionally used in cobalt and nickel cementation. SuperLig® 138 can be used to remove cobalt and nickel from120?170 g/l Zn-solutions at pH 1?2. The Zincor MRT application demonstrated its capability of concentrating large volumes o copper barren impure solution at low cobalt and nickel concentration levels in the feed, to small solution volumes at high cobalt and nickel concentrations. Around 99.5% of the cobalt was removed from solution with cobalt impurity levels in feed varying between 10 mg/l and 26 mg/l.

Jan 1, 2002

By S. T. Johansen, C. Colomb, B. Ravary

Combustion and thermal NOx formation have been modelled using the Computational Fluid Dynamics (CFD) commercial code Fluent 6.1. The aim was to predict and give a better understanding of the combustion in electric arc furnaces for the production of ferro-silicon and silicon metal. Another important objective was to assess the impact of a number of operating parameters on the NOx formation. The CFD tools used are de-scribed with a special focus on models for species and turbulence transport. Sensitivity studies have been carried out to study the influence of several parameters: sub-models, process gas composition and distribution at the charge surface and influence of the presence of SiO. The main conclusions are: ?Using the combination of a realistic design, boundary conditions and models, the simulated NOx level is in quantitative agreement with measurements. The presence of water vapor is particularly important because of its influence on the specific heat of the mixture and resulting temperature. ?Release of significant amounts of SiO from the charge surface results in an important increase of NOx, even if we applied a simplified combustion model for SiO gas. However, because of lack of thermal and compositional data for blowing situations (when SiO flows directly from the arc cavity through open channels to the charge surface), no quantitative validation is possible. The way SiO is distributed (uniformly or as a jet) has a limited impact on the result in our computations.

Jan 1, 2007

By S. Parada, P. T. Jones, M. Guo, S. Smets

The corrosion behaviour of a high-quality rebonded magnesia-chromite refractory in contact with a vacuum oxygen decarburization (VOD) slag with high Al2O3content (15?20 mass per cent) is investigated under VOD process conditions by rotating finger tests in a vacuum induction furnace. The refractory degradation mechanisms are studied by the characterization of corroded microstructures using scanning electron microscopy, equipped with energy dispersive spectroscopy. The influence on the refractory wear of the process temperature and the Al2O3content in the slag is discussed. Keywords: corrosion, magnesia-chromite refractory, VOD slags, vacuum induction furnace

Jan 1, 2004

The aim of this investigation was to study the influence that varying production rates have on iron sinter quality. This was done by performing sinter pot tests at different pressure drops over the sinter bed, namely 11 kPa and 15 kPa (for 500 mm total bed depths). During each of the sintering processes temperature-time profiles were recorded of the top, middle and bottom layers of the sinter bed. On completion of the sinter process the sinter cakes were divided into top, middle and bottom layers. The physical properties of each layer were subsequently characterized by performing a tumbler test and a sieve analysis. A comprehensive mineralogical study was also conducted on each layer. This study revealed that sinters of similar cold strength could be produced under the examined production rates. However, a higher production rate was accompanied by an increased amount of fines. The cold strengths of both sinters significantly increased from the top layer to the bottom layer of the sinter bed. This strength variation is not related in any simple way to the phase composition. Keywords: Sinter, sinter bed, production rate, phase composition, cold strength, tumbler index, sieve analysis, temperature-time profile

Jan 1, 2003

By G. M. J. van Heerden, R. C. W. Webber-Youngman

"This article describes the re-engineering principles applied in the design of a personnel transportation system for the Bafokeng Rasimone Platinum Mine in the Rustenburg area of South Africa. It incorporates conveyor belt travelling, chairlift operation, and also includes consideration of proposed changes/modifications to the existing conveyor belt infrastructure.The purpose of the project was to identify, through a process of evaluation, the appropriate option and/or combination of transportation options that would be safe in terms of personnel transportation as well as cost-effective. Alternative measures for transporting personnel (not using belt riding) would have a significant positive spin-off, increasing the availability of the belt and thereby increasing production. This paper explores the feasibility of interventions that would improve safety through eliminating risk associated with personnel transportation as well as contributing towards improving the mine’s position on the cost curve.The design in consideration at the Bafokeng Rasimone Platinum Mine consists of two shaft systems, namely the North Shaft and South Shaft, each comprising twin decline shafts. One of the decline shafts is equipped with a conveyor belt for rock and personnel transportation, and the other with a winder for trackbound material transport. The conveyor belt has been used for personnel transportation since the commissioning of the shafts. The conveyor belt is equipped with platforms for personnel getting off and on the belt and a number of safety devices designed to ensure safety while travelling on the belt. Intensive training in the practical aspects of belt riding is given to every person, and unsupervised riding on the belt is permitted only once belt riding competence is demonstrated. Despite this, the safety results were poor, with 106 injuries between 2006 and May 2013. Fortunately, no fatalities were reported during this period.An investigation of alternative means for personnel transportation or engineered solutions to the current conveyor belt infrastructure in the safest, most effective, and most economical way was therefore needed. There was a major risk of safety-related stoppages being imposed following another belt accident/incident. This would prevent the mine from transporting personnel underground by belt and result in major production losses. From the commissioning of the Phase 2 shaft deepening project on both shafts, dedicated chairlifts have been used for personnel transportation as opposed to the conveyor belt installed in the Phase 1 area. The chairlifts have been in operation since 2004 and no chairlift-related incidents have been recorded thus far. According to safety statistics, it is clear that the chairlift is the safer method for the transportation of people in the shaft.To fulfil the objectives/scope of this study, it was recommended that both primary (new chairlift decline with infrastructure) and secondary options (modifications to the current conveyor belt infrastructure) be considered for implementation on both the North Shaft and South Shaft to reduce or eliminate accidents/incidents as a result of belt transportation. The associated capital expenditure would be approximately R200 million. Considering the future impact on the business as a whole, this would definitely be capital well spent."

Jan 1, 2016

By F. Peer

In most coal preparation processes, water is a necessary medium, but the presence of water in coal after it has been cleaned has a negative impact on transportation costs, handling and specific energy values. The utilization of super absorbent polymers (SAP) in the nappy application is well known. The concept of utilizing these polymers was investigated for the purposes of dewatering coal and other fines, generated by preparation processes such as flotation. SAPs are granular highly cross-linked synthetic copolymers with excellent water-absorbing properties. The dewatering process is characterized by three main stages: (a) contact of super absorbent polymer with high-moisture fine coal; (b) separation of dewatered fine coal from super absorbent polymer; and (c) regeneration of used super absorbent polymer, by exploiting its response to changes in conditions such as pH or temperature. Preliminary tests showed the separation step to be very difficult. The novel idea of encasing a given amount of polymer in a water permeable cloth solved this problem (of separating the swollen polymer from the dewatered coal). Preliminary tests investigating the effectiveness of the sachets of polymer showed a drastic decrease in the moisture contents of slurries. Furthermore, it was shown that it was possible to regenerate the polymer (still within the sachets) through thermal drying. A full-scale experimental programme was then followed to accurately determine the feasibility of using sachets of SAP. The experimental variables were initial slurry moisture content and polymer dosage. It was observed that the sachets seemed to work fastest and most effectively at high moistures and also at higher dosages of SAP. Regeneration of the polymer was also investigated, using two methods: thermal regeneration and pH-induced regeneration. The experimental variables, for investigating the regeneration process, were method of regeneration and grade of water used. Thermal regeneration at 70°C seemed to work successfully. Although the cost of using thermal energy is still a problem, the safety aspect (fire hazards) has been addressed since the polymer does not ignite when heated, unlike fine coal particles that may do so. The alternative method of regeneration, which exploits the pH-sensitivity of the polymer, was less successful, and further work needs to be conducted.

Jan 1, 2003

By M. Seeger

The demographics and the growing numbers of people provide a strong signal that the demand for electrical power in Southern Africa will grow considerably over the foreseeable future. Without a steady and increasing supply of electricity development of the continent is likely to be constrained. The inventory of solar, wind, hydrothermal, geothermal and biomass resources will probably provide sources of energy for the future The parallels between extraction of natural resources in the minerals industry and the green energy industry is striking, and the well-established project development process in the minerals industry provides an ideal and useful template for comparing the establishment and development of green energy projects. The potential levels of power generation and carbon savings are described.

Jan 1, 2010

By M. Sephton

Slat-band chains, currently manufactured from Type 430 ferritic stainless steel, are used as conveyors in various industries. A process to strengthen these chains?with the aim of prolonging the lifetime of the conveyors?was developed recently. The process entails heat treating the cold-worked chain at 475°C,strengthening the material by precipitation of the Cr-rich phase a? at relatively long periods of aging. In the present work, it was found that increasing the interstitial content by solution heat treatments (at 880°C or 930°C) prior to cold rolling and aging, causes an increase in strength at shorter aging times as a result of the precipitation of chromium-rich carbides and nitrides. The solution treatments can introduce martensite into the microstructure if carried out at a sufficiently high temperature. This, along with the deformation caused by cold work, also increases the strength. Corrosion resistance is not affected by the treatments, but ductility is lowered. However, calculated critical crack lengths indicate that solution treatment at a temperature below the Ac1allows for a larger critical flaw size, and that the lifetime of the chains will probably be determined by fatigue. Although the duration of the service of the chains are reportedly controlled by wear, with these treatments the tensile strength of the material is increased to within acceptable limits for conveyor chains. The tensile strength is an indication of the wear or abrasion resistance of a material. It is expected that after the treatments, the wear resistance will be improved, but since embrittlement occurs, the fatigue resistance is lowered. It is concluded that the preferred processing route for the chains would be solution treatment at 880°C, fast quenching to trap the interstitial atoms, cold rolling and then aging at 475°C for 8 minutes.

Jan 1, 1997

By S. Marx

More than twenty years ago Sasol, ISCOR, and some parastatals played a major role in ensuring that South Africa had sufficient technical skills. When the economy became tight and business and government were pressurized to decrease costs, the first budgets that were reduced were the training budgets. It seemed to be too expensive and too time-consuming to train apprentices. According to Stacey2, this is a major strategic issue facing the mining industry in South Africa. Two factors added to the shortage of skills challenge: ? Skills erosion and job losses ? Artisans ? currently the economy produces 5 000 but the need is 12 500 ? Level of mechanization in South Africa less than 10 per cent ? Average age of operators and artisans is 50 ? Greater awareness of occupational health effects of hand-held drilling. ? Workplace challenges ? The impact of HIV/AIDS and other employee wellness issues ? Changes and challenges in workplace environment i.e. the mining industry.

Jan 1, 2012

As part of a comprehensive risk analysis which was carried out into the effectiveness of the water barrier between South Deep and Randfontein Estate mines, the potential threat posed by large seismic events was assessed. The study covered several aspects. Firstly, an estimate of the maximum credible earthquake was obtained from a probabilistic analysis of the regional seismicity of the previous 25 years. Allowance was made for ?reservoir-induced? effects by increasing the estimate of the size of the maximum credible earthquake from ML= 5.1 to ML= 5.5. Based on available knowledge of the geological structure, the possibility of such an event occurring in the vicinity of the barrier pillar was estimated. The possibility of substantial damage to the barrier rock mass, resulting as a consequence of a large event, was assessed. The likely damage to the concrete control plugs installed in five tunnels that penetrated the barrier, which might result from a ?near-miss? by the largest possible seismic event or from a ?direct hit? by a smaller event, was also considered. It was concluded that there was a negligibly small possibility that the maximum credible earthquake could occur close enough to the barrier, and in such a manner, as to cause any damage to it or to the plugs in the tunnels passing through it. The possibility of serious plug damage occurring as a result of a ?direct hit? by as maller event was slightly greater, but still sufficiently remote as to be of no practical concern at all.

Jan 1, 2006

By J. M. Sabio, A. W. Stalberg

Keywords: Pyrometallurgy, furnace, calcium carbide, acetylene, Newcastle The manufacture of calcium carbide in Newcastle, South Africa, was started in the late 1950s by a company called South African Carbide, at the Ballengeich site. In 1978, this operation was bought by the forerunner to the present AECI Ltd, a large producer of commodity chemicals at the time. Production continued at this site until 1992. In the meantime, Karbochem, an operating division of Sentrachem Ltd, was also manufacturing carbide in Newcastle, as a building block for the manufacture of synthetic rubber. In 1990, the Karbochem calcium carbide operation was closed down. In 1992, the AECI carbide business and the Karbochem production facility were amalgamated, and production continued under the Karbochem name. In 1997, the Dow Chemical Company bought the holding company of Karbochem, and the carbide business continued operations until 2003. In June 2003, the business was sold to a management consortium as SA Calcium Carbide (Pty) Ltd. Later, in October 2004, 100% of the shares were acquired by the Andina Group. Today, the Andina Group, consisting of SACC from South Africa, CIL from UK, and ANDINA from Argentina, has become a global leader in the manufacture and supply of calcium carbide and calcium silicon, ferro silicon 75% and derivatives, recarburizers with low nitrogen content, acetylene, carbon black, micro-silica, and silicon metal. The production facilities at Newcastle comprise a 52 MVA submerged arc furnace of a closed design, carbon monoxide gas recovery, recovery of fine raw materials via a hollow electrode system, and an extensive computer-controlled process. These all enable an efficient state-of-the-art operation. The downstream processing facilities consist of screening and drumming facilities, milling facilities, an acetylene generation plant, and an acetylene carbon black plant. Clearly, SA Calcium Carbide (Pty) Ltd has a long history of supplying quality calcium carbide to the industries that it proudly serves.

Jan 1, 2006

By J. -W. Kim, Y. -B. Kang, H. -G. Lee

The effect of SiO2addition on the decomposition of Li2CO3was investigated at temperatures up to 1000ºC. It was found that addition of SiO2greatly enhanced the decomposition of Li2CO3. The main decomposition reaction started at around 600ºC, and completed just above the melting point of Li2CO3. The major decomposition product was Li2O?SiO2irrespective of the Li2CO3to SiO2mixing ratio while both reactants were available. It was ascertained that a liquid layer betweenLi2CO3and SiO2particles formed and facilitated the decomposition reaction. The governing reaction of the decomposition was the one between the dissolved Li2CO3and SiO2in the liquid layer to form Li2O?SiO2. The decomposition rate was independent of the Li2CO3/SiO2mixingratio until either one had been completely exhausted. When excess Li2CO3existed, it further reacted with the initial product of Li2O?SiO2to form 2Li2O?SiO2. When SiO2was found in excess, on the other hand, no further reaction took place. This is attributed to the fact that uponLi2CO3exhaustion there is no liquid phase available to facilitate further reaction. The apparent activation energy of the decomposition of Li2CO3in existence with SiO2is 198 kJ mol-1.

Jan 1, 2004

By G B. Gnoinski

The Skorpion Zinc Mine and Refinery is situated approximately 25 km north of Rosh Pinah, south-western Namibia. The supergene zinc oxide deposit at Skorpion is hosted in a volcano-sedimentary succession within the para-autochthonous Port Nolloth Zone of the Gariep Belt. Rock types hosting the ore deposit include altered and metamorphosed volcaniclastic and clastic sediments, limestone and rhyolite. At Skorpion, the metallurgical process is unique and the plant design requires minimal fluctuations within a selected feed grade. In addition, the presence of limestone inter-fingered with ore in some areas of the deposit results in dilution problems which may increase gangue acid consumption and therefore processing costs. Hence, selective mining is necessary to ensure the delivery of suitable ore to the processing plant, in order to keep the overall operating costs at a minimum. A complex control system is in place and is capable of a high degree of selectivity. The paper describes the grade control system in place at Skorpion Mine which ensures that the qualities of the blocks planned for mining and the material being mined meet the stringent process requirements of the refinery, i.e zinc grade, gangue acid consumption and deleterious elements that may impact on the efficiency and costs of the metallurgical process. Keywords: Skorpion zinc, zinc oxide, supergene, volcano-sedimentary, grade control

Jan 1, 2007

By J. Muller

Keywords: Pyrometallurgy, blast furnace, slag viscosity, slag liquidus temperature, phase equilibria The viscosity of molten slag in blast furnace operations is an important process variable, influencing the rate and location of reactions inside the furnace, as well as the ease with which the final slag could be removed from the furnace. To optimize these processes, it is necessary to estimate the slag viscosity and liquidus temperatures as accurately as possible, and know the target values. Models to predict viscosities and liquidus temperatures, incorporating phase equilibrium calculations, have been developed and validated with measured data. Various diagrams have been developed to illustrate how the properties vary with composition and temperature, including pseudo-ternary diagrams of SiO2-MgO-CaO-Al2O3 for viscosity and liquidus temperature. Models were also applied and methodologies developed to analyse historical blast furnace operations and determine target values.

Jan 1, 2011

By B. R. Broekman, K. J. R. Ford

Over the last decade significant development and use has been made of a simulation model that describes the HCFeMn smelting operations in Assmang Ltd. This spreadsheet based, semi-empirical, predictive model is derived from data from the submerged arc furnaces at Assmang?s Cato Ridge, KwaZulu-Natal smelter site. Departures from the empirical base case mass balance due to changes in the ores, reductant feeds and operating parameters are accounted for by use of fundamental relationships and heuristic type ratios which are applied in an iterative manner in the model. The model performs a sequential set of calculations to iteratively converge on a fully consistent mass and energy balance solution, which predicts Mn alloy and slag output masses and compositions for a given set of feeds. 440 MWh per operating day is used as the basis of energy input. The paper describes the key model components, assumptions made and calculation approach. Added to the mass and energy balance is a cost and revenue balance, which allows prediction of the economic performance for each simulation. Substantial use of the model has been made in simulating the performance of the current Assmang HCFeMn furnaces for both smelter investigations and future production planning. The model has also been a valuable tool in the strategic analysis of the use of future Mn ores and has formed the vital link between mine ore grades (metal and slag elements) and the expected alloy output, grade and profitability. Additionally, the model has been used in benchmarking exercises to predict other Mn smelting operations with remarkable accuracy. The paper highlights some aspects of the approaches taken in using the model to benchmark Assmang?s own furnace performance and cost competitiveness with other producers. For Assmang the development and application of this modelling technology has led to transformation in understanding of the Assmang HCFeMn furnace operations and increased awareness of the potential of its Mn ore bodies.

Jan 1, 2004