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This paper details the preliminary design work carried out before and during the implementation of an extensive backfilling programme on Cooke 3 Shaft, Randfontein Estates Gold Mining Company (Witwatersrand) Limited. The design work is of relevance to any system utilizing a cementitious binder, and the quality control aspects are of particular significance. Problems associated with correlating laboratory results to actual field results are also briefly discussed.

Jan 1, 1988

By F. L. Wilke

The use of operations research techniques and computer models has become entrenched in the mining industry, particularly in the area of mine planning. The paper considers three major areas where increasing efforts are likely to be directed in the future: the integration of multiple disciplines in a single model; the decentralization of computing capacity within a structured network; and the incorporation of sophisticated techniques such as computer aided design and artificial intelligence.

Jan 1, 1987

By M. David

This paper addresses the problem of technological transfer in geostatistics. Expert systems have become popular in certain fields because the needs of the industry are not provided for by traditional concepts and systems of education. The explicit knowledge approach in developing expert systems is presented through two experiments. The first describes a dedicated system written in GOLDEN LISP and the second a shell, using INSIGHT2, which has more general applications. Using expert systems forces on the user a new approach to parameter definition, and as an example an original method for the research of any anisotropy axes is developed which might well be useful in traditional programming. Two examples of application to a coal and a gold deposit are given.

Jan 1, 1987

By D. E. Kraushaar

Ruhrkohle in West Germany evaluates and compares the net present values of long-term periods from its coal mines by a computer assisted long-term planning system. Two main parts of this system are computer programs for the prediction of: (a) mineable reserves and their distribution in longwall panels as a function of dependent geological variables; (b) daily outputs and costs of longwall panels as a function of dependent geo- logical, layout and operational variables. This paper describes the investigations, which ended in the above computer programs: ? the collection of information from past workings and their organization in databases; ? the statistical evaluation of the databases, and ? the resulting correlation formulas. The correlation formulas vary the mean dependent variables as a function of independent variables which can be indicated with high reliability for planning projects in the long run. The system thus serves the purpose of facilitating long-term planning and excluding biased individual judgement of local planning staffs.

Jan 1, 1987

By D. J. Mourant

Day-to-day operations on the Broken Hill mine of the Black Mountain Mineral Development (BMMD) Company require a detailed knowledge of the distribution of the ore minerals within the orebody. The data are acquired by systematic underground diamond drilling of the orebody and subsequent geological and analytical borehole logging. These data are then captured onto a database, available for further analysis. Before mining commences in a mining block, copper, lead, zinc, silver and bismuth assay values, and the specific gravity of each sample, are extracted from the database. 3-dimensional variogram and kriging calculations are performed for each geological zone; for all the metals of interest. A computer representation of the mining block in the form of an ore model is then built using these kriged data. From these ore models information is extracted as required by the Geology Department on the mine, and used in numerous operations. These include: daily grade control to supply optimum feed grades to the treatment plant; the compilation of short, medium and long term production schedules; orebody outline definitions for the detailed planning of mining operations; ore resource calculations. The system has been modified and updated since its inception and provides timely information in a production environment.

Jan 1, 1987

By R. L. Robinson

An analytical framework is formulated to assist mining companies in assessing the relative merits of mineral exploration and acquisition strategies. The anticipated costs, risks, and returns of each strategy are conceptualised using decision trees. Economic criteria - expected net present value, expected return per unit of investment, and the probability of success - for each strategy are derived(from the appropriate decision tree network. Application of the analytical framework is illustrated using the example of a medium-size company in the Canadian base metal sector.

Jan 1, 1987

Material transfer in underground mines often relies on ore and waste pass systems. Over the years the authors have investigated the design and performance of orepass systems in several Canadian and South African mines. It has been recognized that while most mining operations have either implicitly or explicitly clearly defined objectives, in the design and successfully operate orepass systems there seems to be an absence of a strategy on how to best attain these goals. Consequently, it is not surprising that the majority of operations reviewed by the authors experience a number of problems of varying degrees of severity and economic consequences. This is illustrated by reference to both South African and Canadian operations. The second part of this paper focuses on a review of tactical interventions to rectify orepass problems or mitigate their impact. The paper closes with a framework for a flexible strategy for the design and operation of orepass systems. Keywords orepass; orepass design; orepass stability; orepass rehabilitation; orepass operation; orepass strategy.

Oct 1, 2013

By J. Gholamnejad

Determination of the optimum cut-off grades is one of the most important aspects of mine production planning. A cut-off is a grade below which we choose not to process material. This material is treated as waste and dumped. Dumping waste is accompanied by the rehabilitation cost which will affect the overall cost of final production and also the optimum cut-off grade. Rehabilitation cost is the cost per ton of rehabilitating material of a particular type of rock after it has been dumped as waste. One of the most popular algorithms for determination of the optimum cut-off grade is Lane?s method. Lane formulated the cut-off grade optimization, but he did not consider rehabilitation cost during the optimization process. This cost item should be evaluated first, and then considered during the cut-off grade optimization process. In this paper the rehabilitation cost is inserted directly into the cut-off grade optimization process using Lane?s theory. The cut-off grades obtained using the suggested method will be more realistic than ones using the original form of Lane?s formulations.

Jan 1, 2009

By M. Pelser, J. Hagemann

"The Anglo American Platinum Rustenburg Base Metals Refiners (RBMR) is the largest producer of nickel cathode in South Africa. It treats slow-cooled matte to recover a platinum group metal-containing magnetic fraction for downstream processing and a nonmagnetic fraction to produce nickel and copper cathode, cobalt sulphate, and sodium sulphate. The refinery was recently expanded from 21 to 33 kt/a nickel. During the ramp-up phase, the sulphur removal section was found to be a constraint to throughput. Nickel hydroxide is precipitated from nickel spent electrolyte by addition of sodium hydroxide, and filtration of the nickel precipitate allows sulphur to be removed from the circuit as aqueous sodium sulphate in the filtrate. The filtration fluxes were found to be limiting the circuit’s capacity. An obvious solution would have been to install additional filtration capacity at significant capital cost and long lead times. RBMR chose rather to first initiate a collaborative project with Anglo American Technical Solutions to better understand the impact of process conditions on filtration characteristics and to evaluate whether the filtration flux could be increased by improving the quality of the nickel precipitate.A deeper understanding of nickel hydroxide precipitation chemistry and kinetics in the context of high nickel and sodium hydroxide concentrations was developed, guided by precipitation theory and confirmed by laboratory tests and plant observations. It was found that the filtration rate could be significantly improved by modifying the precipitate characteristics. A new precipitation process was engineered and retrofitted into the existing plant. Since start-up of the new precipitation system, the available capacity of the sulphur removal section has more than doubled, and control of the process has improved with the better agitation. This paper describes the theory and results used to design the new agitation system, as well as the impact of the change on capital investment, operability, and process efficiency."

Jan 1, 2016

By C. Botha

The South African democratically-elected government instituted policies and legislation that are intended to bring about change and transformation in the country and have drastically affected different industries, among others, the mining industry. The Mineral and Petroleum Resources Development Act 28 of 2002 (MPRDA) and the Broad-based Socio-economic Empowerment Charter (Mining Charter) were introduced in order to redress previous inequalities and to promote women's employment in the mining industry. This research evaluates the practical implementation of the MPRDA and the Mining Charter with specific reference to women in underground mining. A quantitative research paradigm was used. Data were collected through a process of a face-to-face interview surveys utilizing a structured questionnaire. The research setting was limited to the platinum-mining industry in the area of Rustenburg in the North West Province. The study population consisted of 195 available women working undergound at the mine. It is clear from the findings that mining companies are facing major challenges in their attempt to incorporate women in underground mining activities. Company policies regarding these issues must be firmly in place; however, the challenge lies in the translation of these policies into practice. In this regard, managers will have to play a leading role in the successful phasing in of women into the underground mining arena.

Jan 1, 2012

By E. L. Forner, G. M. Miller, J. Scheepers, A. J. du Toit

"The sizing, designing, and costing of copper electrowinning circuits requires an in-depth understanding of the fundamental relationships between circuit parameters and the practical operation requirements. The aim of this investigation was to optimize total copper electrowinning project cost by mapping the operating limits of key mechanical equipment. The model was compiled by mapping various cellhouse layouts in terms of number of cathodes per cell, crane productivity, stripping machine productivity, and rectifier–transformer (rectiformer) sizing using data tables for sensitivity analysis. These parameters were then collated and evaluated on a cost by size basis. The model provides an optimum band of operation for cellhouse productivity and project capital cost for a typical range of production throughputs, from 10 kt/a to 200 kt/a cathode copper. The information may be used as a high-level selection guide to assist with identifying a costeffective copper electrowinning circuit design for a specific production rate. The data was validated and compared with existing copper electrowinning cellhouses around the world that typically install no more than 84 cathodes per cell. IntroductionThe sizing, designing, and costing of copper electrowinning (EW) circuits require an indepth understanding of the fundamental parameters as well as the practical requirements to optimize cellhouse productivity and capital cost. Although a significant amount of work has been done designing new copper electrowinning circuits, an in-depth evaluation of world operating data reveals that the number of cathodes per cell, which affects cellhouse layout and productivity, is not consistent for a specific production rate (Anderson et al., 2009; Robinson et al., 2003, 2013). Based on this premise, Kafumbila (2017) suggested that there are unanswered questions, such as ‘why are the numbers of cathodes per cell different for copper production rates of 20 kt/a and 40 kt/a?’In this paper, data tables are employed to map the operating limits and costs of key Cu EW equipment. An overall Cu EW project cost map is then compiled by collating optimum cellhouse layout (number of cathodes per cell), optimum crane productivity, optimum"

Nov 1, 2018

By C. Botha

The South African democratically-elected government instituted policies and legislation that are intended to bring about change and transformation in the country and have drastically affected different industries, among others, the mining industry. The Mineral and Petroleum Resources Development Act 28 of 2002 (MPRDA) and the Broad-based Socio-economic Empowerment Charter (Mining Charter) were introduced in order to redress previous inequalities and to promote women?s employment in the mining industry. This research evaluates the practical implementation of the MPRDA and the Mining Charter with specific reference to women in underground mining. A quantitative research paradigm was used. Data were collected through a process of a face-to-face interview surveys utilizing a structured questionnaire. The research setting was limited to the platinum-mining industry in the area of Rustenburg in the North West Province. The study population consisted of 195 available women working undergound at the mine. It is clear from the findings that mining companies are facing major challenges in their attempt to incorporate women in underground mining activities. Company policies regarding these issues must be firmly in place; however, the challenge lies in the translation of these policies into practice. In this regard, managers will have to play a leading role in the successful phasing in of women into the underground mining arena.

Jan 1, 2012

The variety and sources of sampling errors have been studied since the late 1800s, but the pioneering work of Pierre Gy in the 1950s provided insights into sampling as an error generating process. Total sampling variance is a measure of the total sampling error, but disaggregating the variance into its component parts is problematical. Ten sources of error and error generating processes have been identified, some of which can be eliminated through rigorous application of the principle of correct sampling. Others can only be minimized but never eliminated. Three principal questions relating to the appropriate mass of a sample, the fragment size of the sample and the size of the associated error are addressed. These questions relate principally to the Fundamental Error (FE), the only error that can be estimated before the sampling event. Aspects of constitutional and distributional heterogeneity are examined, as are the essential components of Gy?s formula including the shape factor (?), the granulometric factor (g), the mineralogical composition factor (c), and the liberation factor, l. Applications of Gy?s equation to the problems of sampling in the minerals industry are explained using real-life examples. The approach to sampling taken by Pierre Gy provides an excellent inferential relationship between the mass of material to be sampled, the size of the fragments being sampled, and the relative variance of the sampling error. It also provides solutions for three of the main problems associated with the Theory of Sampling.

Jan 1, 2007

Anglo Platinum is in the process of introducing a number of initiatives, varied in nature, on a scale that will impact operations in the short, medium and long-term. The advent of mechanization on a large scale and the introduction of new mining technologies therefore require a different approach to the design of ventilation and cooling systems. In addition, the ventilation and cooling systems serving increasingly deeper operations will place a greater demand on electrical power consumption?this in an environment where power generation is limited and increasingly expensive. Ventilation and cooling systems currently being employed in platinum operations have evolved from practices first pioneered in deep level gold mines. However, in modern and future platinum mines, deepening of operations will take place in a somewhat different environment?particularly in terms of geothermal settings and electrical power utilization. This provides the opportunities to devise novel and energy-efficient ventilation and cooling strategies tailor-made to meet these challenges. The need for refrigeration and cooling at depth will increase the capital and operational cost component of ventilation systems and the medium-term limitations on the availability of electrical power will require the provision of innovative systems. The increased use of diesel-powered vehicles underground, the viability of energy recovery and feasibility of thermal storage opportunities are discussed in this paper. Some of the challenges and the solutions currently proposed in terms of ventilation system design, refrigeration plant selection and chilled water distribution methodologies are described. Changes in strategies core to this discipline that affect the health and safety of employees and the profitability of modern operations are deemed necessary to support the transformations that are envisaged.

Jan 1, 2008

By R. C. Hochreiter

The paper gives a technical review of the history, occurrence, mining, metallurgy, and end-uses of the platinum-group metals in South Africa, with most emphasis on platinum and palladium. The platinum industry has grown, from the first discovery of the metal in South Africa (in the central Transvaal) in 1923, to the present time, when the country is the largest producer of platinum 10the world, supplying almost 70 per cent of the platinum on the world market.

Jan 1, 1985

By P. G. Van Der Walt

This paper deals with the reticulation of deslimed tailings from surface to the stope face underground. Reference is made to the experience gained at the pilot plants operating on four of the gold mines administered by Gold Fields of South Africa, as well as at the full-scale system at East Driefontein which was commissioned recently. Mine-wide backfill systems are currently being installed on five other mines administered by Gold Fields. These six full-scale systems are capable of handling more than 270 000 tons of backfill solids per month. The type of reticulation system chosen, the selection of flowrates and the composition of the slurry, as well as the selection of the appropriate pipes and ancillary equipment are discussed. Both theoretical and practical aspects are taken into consideration. Other aspects covered include the design of underground storage dams and communication systems.

Jan 1, 1988

This paper presents a quantitative approach to the problem of determining design capacity and field dimensions of underground coal mines using room- and-pillar mining systems. In evaluating these design variables, relationships among mining costs, number of production sections in mines, location of central shafts, mine field dimensions, section production, mine output, and cost of production losses due to underground man-traveling are analyzed. Thereby the unit cost of coal is expressed as a function of the design variables as well as input parameters such as seam angle, seam thickness, seam depth, underground traveling speed of men, mine recovery and plant recovery. The problem is then formulated as a nonlinear optimization model in terms of minimizing the unit cost of coal subject to a set of constraints and solved analytically for flat seams and numerically for inclined seams. Sensitivity analysis of the variables is also included in the paper.

Jan 1, 1987

By J. O. Claassen

A study was initiated and solutions implemented to address the root causes of a 30%?40% lower than predicted product yield achieved at a Mpumalanga coal mine. A holistic MRTM approach, which focused on improving exploration, geological sampling and analysis, geological modelling, planning, mining, and beneficiation practices, was used. The study indicated that deviations in the planned versus actual yields at the DMS plant were caused mainly by incorrect geological yield predictions, high and variable levels of dilution, and near-dense material, as well as the textural properties of the ore. Keywords MRTM, mining value chain improvement, Witbank coalfields, complex geology.

Oct 1, 2013

By R. Venter

Uranium in the tetravalent state has very low solubility in acid and alkaline solutions and needs to be oxidized to the hexavalent state to become soluble. In acid leaching of uranium the uranium is oxidized by ferric iron, which in turn is reduced to ferrous iron. The reduced iron needs to be oxidized to the ferric form to allow the uranium dissolution reaction to proceed. This paper considers the known and proven oxidants used in acid leaching of uranium. These include manganese dioxide, sodium chlorate, hydrogen peroxide, ferric iron, oxygen and sulphur dioxide/air (oxygen). The reaction chemistry of each oxidant as well as the practical applications are considered and discussed. All the oxidants discussed work adequately in acid leaching of uranium and it is possible to engineer solutions for the use of the oxidants in acid leaching on plant scale. The availability and supply of the oxidant as well as the cost and environmental impact of the oxidant plays a major role in the selection of a suitable oxidant. The location of the plant will also have an impact on these issues.

Jan 1, 2009

By J. Kempken, T. Schreiter, R. Degel, H. Schmieden

After a short summary of the historical milestones of the submerged arc furnace, the paper will highlight different applications and their specific smelting furnace requirements in the non-ferrous area. Additionally, aspects of rectangular furnace design and the features of the copper cooling system for the side wall will be emphasized. Finally a state-of-the-art design tool as well as a new invention to improve slag cleaning technology will be featured, which shows great potentials especially for the PGM and copper related industry. Keywords: submerged arc furnaces, aerro alloys, non-ferrous, copper, slag cleaning, PGM, rectangular furnace, DC technology

Jan 1, 2006