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Mining is a business involving extraction of commodities of value to society from non-renewable resources. Consequently there is only one opportunity to extract ore from the ore body in order to unlock the value potential encompassed in the asset. It is therefore imperative that the maximum value is unlocked during the extraction programme, considering the relative wealth generated for shareholders and society, the sustainability of society, the environment and the operation. The bulk of the value that is unlocked is usually embedded in the initial design process. How do you measure sucess The most common measure of success is the return on investment, which is unlocked during the extraction process. This is usually only determined and locked-in during the study process. Another measure of success is the profitability that is achieved on a monthly basis. A further measure would be the enhancement the asset affords to the share price of the operation. Increasing focus on sustainable development requires that the impact on the society and environment received high priority as well. All these measures are largely encompassed in the cash flow and the discounted cash flows. This paper focuses on the dynamics of the cash flow and the most significant elements influencing return in investment. These include the mine design, production volume, sustainability, risk and valuation techniques. When do you add the most value? There are many different phases and definitions noted by different authors to demonstrate and standardise the study process for new projects. This paper is based on a process with 3 major components namely a conceptual study, a prefeasibility study and a feasibility study.

Jan 1, 2007

By H. M. Friede, R. H. Steel

Notes on Iron Age copper-smelting technology in the Transvaal by H. M. FRIEDE, Ph.D. and R. H. STEEL (Visitors) Earlier reports on Iron Age copper metallurgy and copper-smelting techniques in the Transvaal are surveyed, and a description and tentative classification of the copper furnaces are given. The analyses of furnace slags and sherds of glazed crucibles from archaeological sites of the Transvaal and the neighbouring Orange Free State pro. vide evidence of copper smelting there in Iron Age times. . An investigation conducted by the Department of Archaeology of the University ofthe Witwatersrand provided information on the details of furnace construction and smelting processes, on the composition of the materials used and produced, and on the making and handling of tools and accessories, such as bellows and tongs, needed by Iron Age smelters. Three models (the KaondejVenda furnace, the Rooiberg crucible furnace, and the Uitkomst furnace) were constructed and operated as a demonstration of Iron Age copper smelting as it was practised in the Transvaal.

Jan 11, 1975

By C. Yu, N. Topliffe, H. Song, W. Yu

The water separation pump is a highly effective alternative for medium pressure (1.6?6.4 MPa) slurry pumping requirements and has been widely used in industry since it was invented in the 1980s. The water separation pump is powered by a single or multi-stage clean water centrifugal pump. The water separation pump combines the advantage of high flow centrifugal pumps with the high pressure capability of reciprocating pumps. The clean water pressure is exchanged to slurry kinetic energy through the separating chamber, the principle component of the water diaphragm pump. Currently in its the third generation, the separation chamber uses a ball and flexible water seat that provides a true separation mechanism and can completely isolate the two fluids with near zero water loss.

Jan 1, 2007

By N. Kernahan, T. Zaniewski

Threshold blasting involves the use of small amounts of high explosive to break and fragment hard rock without having to evacuate mining personnel. The method is easily assimilated and effective in rockbreaking, but requires rigid control on drilling, charging and timing. Current underground trials are aimed at fine-tuning the amount of explosive energy and blast hole geometry to allow the firing of multiple sets of shot holes in a continuous manner. Through correct procedures, the after-blast fumes, dust and fly rock can be contained so as to provide a safe working environment. Threshold blasting hugely reduces the volumes of explosives used in mining and brings to maturity the potential of the process begun by Alfred Nobel when he introduced nitroglycerine, and later dynamite, to mining. Its key contribution is its enabling of continuous mining operations with well understood and relatively low cost technologies. The use of batch blasting, employing large burdens holds the greatest potential for delivering high flow rates of ore at minimal cost. There is good potential for rapid evolution of the concept.

Sep 1, 2001

By H. S. Eisner, J. -P. Leger

Published South African fatality and injury statistics for mine accidents are investigated. Where possible, the South African statistics are compared with those of other countries. Commonly held attitudes to the South African accident experience are also examined. Analysis reveals that the published accident rates present a more favourable picture than the rates actually experienced by underground workers. In addition, fatality rates in South African underground gold and coal mines do not differ significantly and have remained stable over the past decade, although the injury rates have decreased rapidly. No evidence was found that this is due to improved safety, and a comparison with international fatality and injury data suggests that it is not. The underground fatality rate for South African coal mining is, on average, eight times that of the UK, four times that of all EEC coal mines taken together, and over double that of the USA. Despite the unreliability of the injury rates, much has been made in South Africa of their rapid decline, an emphasis that appears to be misplaced.

Jan 1, 1988

By D. J. C. Taylor, R. A. Kruger

Unbridled mining operations can have a serious negative impact on the surroundings. With the recent increased awareness of the need for environmental conservation and the resulting advances in environmental control, the mine planner has new tools at his disposal for the successful implementation of mining projects while avoiding negative environmental effects. This paper discusses the environmental strategies adopted in the planning and commissioning of a trial underground coal mine. The minimization of negative environmental effects is demonstrated and, where applicable, environmental benefits are examined.

Jan 1, 1986

This paper illustrates the application of numerical modeling methods, in conjunction with limit-equilibrium techniques, to the location of critical slip surfaces in slope-stability problems. Initially, the Spencer slice-based method of analysis is introduced, together with a dynamic-programming algorithm for slip-surface location. This limit-equilibrium method is assessed critically through the use of an illustrative problem. The technique is then extended to locate the critical slip surface for a similar slope, but with more complex constitutive and yield relationships for the material comprising the slope. To this end, the use of the stress field generated from a finite-difference program, together with a dynamic-programming search routine, is presented as an advanced technique of slope-stability analysis for engineers.

Jan 1, 1993

Abstract A new approach is introduced for study of the behaviour of geotechnical strength parameter prior to slope analysis to ascertain whether strength parameters of slope materials are homogenous or heterogeneous at different mine depths. The strength parameters used for the study are uniaxial compressive strength, tensile strength and shear strength. The analysis is based on statistical analysis of variance technique for one-way classification. The application of the technique is given through a case study in an openpit mine. Auszug Eine neue Annäherung wird für Studie des Verhaltens des geotechnischen Stärke Parameters vor Steigunganalyse eingeführt, um zu ermitteln, ob Stärke Parameter der Steigungmaterialien homogenous oder an den unterschiedlichen Grube Tiefen heterogen sind. Die Stärke Parameter, die für die Studie verwendet werden, sind einachsige zusammenpressende Stärke, Dehnfestigkeit und Scherstärke. Die Analyse basiert auf statistischem varianzanalytische Technik für Einwegklassifikation. Die Anwendung der Technik wird durch eine Fallstudie in einer openpit Grube gegeben. Abstrait Une nouvelle approche est présentée pour l'étude du comportement du paramètre géotechnique de force avant l'analyse de pente pour établir si les paramètres de force des matériaux de pente sont homogenous ou hétérogènes à différentes profondeurs de mine. Les paramètres de force utilisés pour l'étude sont résistance à la pression uniaxiale, résistance à la traction et résistance au cisaillement. L'analyse est basée sur statistique la technique de l'analyse de variance pour la classification à sens unique. L'application de la technique est donnée par une étude de cas dans une mine à ciel ouvert.

Jan 1, 2003

By W. F. A. T. Meihack

The scope of this paper is confined to gas-fluidized beds in pyrometalurgical applications. After considering the general characteristics of these fluidized beds, the author deals with their potential applications, using the following processes, which are currently under investigation, as examples: pretreatment of chromite, prereduction of manganese-ore and iron-ore fines, roasting and prereduction of ilmenite, and roasting and pyrolysis of gold-bearing pyrite. He concludes that fluidized beds are potentially of great benefit to the metallurgical industry, although much developmental work remains to be done.

Jan 1, 1986

By W. L. Van Heerden

In situ complete stress-strain characteristics of large coal specimens by W. L. VAN HEERDEN, B.Sc. Hons. (Pret.) (Visitor) The significance of ;n situ tests on large coal specimens is briefly reviewed. Tests aimed at obtaining complete stress-strain characteristics of large coal specimens with high width-to-height ratios are described. A formula for the relationship between strength and width-to-height ratios of coal pillars is proposed, and the influence of width to- height ratios on the deformation characteristics of pillars is discussed.

From a consideration of the functional requirements of a stope-support pack, simple design principles were developed. The material and dimensional properties of the different components of the pack were determined from a series of laboratory tests. The most important requirement for an adequate pack is that the cushioning layers of timber between the concrete brick layers should provide sufficient transverse reinforcement. The tendency of the compressed timber to creep is shown to be a serious limitation to pack performance and must therefore be an important consideration in the overall design of supports.

Jan 1, 1978

By A. Singh, R. R. Maclachlan

SYNOPSIS A back-analysis procedure based upon 35 mm photography was developed on a laboratory scale for the pur¬pose of determining the percentage of oversize particles known to be present in heaps of fragmented rock. Eight simple blends of crushed stone containing varying percentages of oversize on a 1:40 modelled scale were examined. Simulated test conditions for the following were subjected to the photographic study: (1) a bench heap, (2) the surface exposure of a partially excavated heap, (3) a gravity-sorted surface as occurs on an apron dump, and (4) four quadrant views of an incrementally built conical heap of rock fragments. The best back-analysis determinations were obtained from (4), the cone, over all eight blends of fragments. The mean error was within -0,16 per cent of the true value, with a range of ± 1,872. This was for oversize contents of 5 to 20 per cent where a minimum 25 per cent of the photograph area was processed by digitizer. The worst results were from the apron dump at - 1,462 per cent for a mean error of ± 4,174 per cent. The intermediate results were from the undisturbed bench at -0,186 per cent with a mean error of ±2,862 per cent.

Jan 1, 1989

By G. M. Thain

Ancient Mining - The following three contributions were received for publication in addition to the preceding papers. 1. Ancient gold-mining sites in the Transvaal G. M. THAIN* Pre-European gold mining and working in South Africa is a tantalizing field for conjecture. Well over thousand sites have been identified in Rhodesia, but here we have had to reach double figures, judging by published accounts. Geologically, the Transvaal is less amenable primitive exploitation, but it difficult to reject the idea that the knowledge gained to the north did not have its influence south of the Limpopo.

Jan 1, 1974

By J. van Zyl Visser

The advancement in Information Technology has resulted in a change in workflow practice in our Mineral Resource Management (MRM) offices on the mines and at our corporate office. This paper discusses the AngloGold approach in defining an IT strategy for MRM, a brief overview of systems usage and benefits. AngloGold has gone through a transformation phase and has positioned itself as a world-class, low cost producer. To support this objective, an initiative has been launched to provide the MRM division with an integrated MRM technical suite of systems with support of a Management Information System. Technical systems for a tabular orebody are not freely available and hence it took AngloGold almost seven years and a significant amount of capital to develop an integrated suite of technical systems. AngloGold MRM IT adopted the typical Zachman framework (value chain) approach in the analysis process and formulated the final deliverable in terms of AngloGold’s strategy. Major benefits have been realized through the ability to change planning scenarios in a short period of time and hence be able to increase reserves and NPV. The development of MRIS, which will become the flagship in AngloGold’s portfolio of systems is in phase two and this system will allow AngloGold to publish Resources and Reserves as per SAMREC and the JORC Code at will. The availability of information at all levels of the operations has made making decisions easier and hence some specialized reports such as the Basic Mining Equation were developed from the Corporate Data warehouse and from the MRM reporting database. Decision Support Systems(DSS) such as Business Objects and Oracle Express are now being used to assist in the process. The decision to use Business Objects to replace SAS reporting as the core reporting tool has resulted in the empowerment of the user and major cost saving as far as the use of consultants to set up standard reports.

Jan 1, 2003

By S. V. Rungan

The modern mining industry is increasingly being tasked to comply with various legal, industry and social prerequisites. In addition to complying with these, the mining industry is further expected to effectively report on their compliance. Although there are many models that aid the mining industry in compliance and reporting, it is perhaps opportune for a new model to be introduced. The Compliance Spindle is postulated as a new and alternative model which is easy to understand and has the possibility of implementation in South Africa and other jurisdictions as well. The Compliance Spindle is also an effective tool to educate future compliance officers. The new model provides for all aspects of compliance and reporting and can be easily modified to take account of new developments in the mining compliance and reporting arena.

Jan 1, 2010

By Keith Rowley, Neal Harries, David Noon

The management of risks associated with slope instability is an essential process in the safe and economic operation of open cut mines. The ?slope stability radar? (SSR) has been developed to better manage those risks. The SSR remotely scans rock slopes to continuously measure any surface movement and can be used to detect and alert users of wall movements with sub-millimetre precision. The high level of movement precision and broad area coverage of the rock face can allow for a better understanding of the geomechanics of slope deformation, including magnitude of potential failures and additional warning time of impending instability. Additionally, radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, 24 hours a day. SSR systems have been deployed in many mines in Australia, Indonesia, South Africa, Zambia, Chile and the United States. Greater than 70 rock falls and waste dump failures (from several to millions of tonnes) have been monitored, and on every occasion precursor ?warning? movements were recorded by the SSR. This technology enables a radical change in the management of risks in open cut mining. This paper will present recent case studies of the SSR operation in coal and metalliferous mines.

Jan 1, 2006

By S. Asokan, Ch. V. G. K. Murty, R. Upadhyay

Zircon (ZrSiO4) is the most frequently found zirconium ore occurring in heavy mineral sands, from which it is extracted as a co-product in the production of ilmenite and rutile. Estimated world reserves of zircon are 124 million tonnes, highest in Australia (around 56 million tonnes), followed by Mozambique (15 million tonnes), India (12.6 million tonnes) and South Africa (12million tonnes). Zircon finds its application in ceramics (54%) and refractory industries (14%), which account for 68% of zircon?s total world consumption of 1.20 million tonnes. The rest (32%) is consumed in foundry, TV glass, zirconia chemicals and other applications. It is a long recognized feature of the zircon industry that supply is totally dependent upon the concurrent production of titanium minerals. But in recent years, several new developments such as the discovery of zircon-rich mineral sands in Australia, the continuing trend of higher prices of zircon and increase in trade of lower quality zircon have changed the scenario. These factors have prompted more intensive efforts to increase the recovery of zircon, particularly in the process for separating zircon from alumino-silicate minerals. Tata Steel?s proposed heavy mineral sands deposit contains on an average 10% heavy mineral content and 15% slimes of the size below 63 micron. Mineral assemblages of the resource contain65?70% ilmenite, 4?6% rutile, 4% zircon, 16% sillimanite and other minor minerals. Wide size range and tenacious iron oxide coating are the inherent characteristics of this deposit. High concentration of sillimanite among the non-magnetic heavy minerals and heavy surface coatings on the minerals are challenges for high recoveries and production of premium grade zircon. This paper outlines various process steps that were taken at pilot plant stage to produce zircon of premium grade and subsequently develop the appropriate flow-sheet.

Jan 1, 2007

By D. Wines

"Slope stability analyses have traditionally been undertaken in two dimensions assuming plane strain conditions. Although three-dimensional analysis techniques are widely available and used routinely for open pits, two-dimensional analyses are still more common due to the relative ease of model construction and the relatively rapid simulation times.Two-dimensional analyses will often produce different results to three-dimensional analyses for the same slope. It is generally thought that two-dimensional analyses will produce more conservative results. The main reason for the differences is the ability of three-dimensional analyses to account for the three-dimensional nature of the various model inputs, including the slope geometry, the distribution of soil and rock mass domains, the orientation of geological structures with respect to the excavation face, the orientation of the in situ stresses, and the distribution of pore pressure. In some cases, for a long, straight slope in basic geological conditions, two-dimensional analyses can provide a reasonable representation of the problem. However, in many cases, the inability of a two-dimensional analysis to represent the true three-dimensional nature of the problem will lead to unrealistic analysis results.This paper discusses the reasons, as detailed above, for the differences in two-dimensional and three-dimensional analysis results. Work by others is summarized, and additional numerical analyses are performed to provide an improved understanding of the effects of slope geometry, structural orientations, and in situ stresses on predicted stability. Case studies are presented for both stable and unstable slopes, and the behaviour of these slopes is related to the three-dimensional nature of the slope geometry and geology.The previous work, the new analyses performed here, and the case studies show that it is often important to provide a realistic representation of the slope in three dimensions in order to obtain reasonable stability analysis results. This is particularly true for hard rock environments where structurally controlled failure mechanisms are most likely. The paper also highlights the fact that back-analysed properties obtained from one analysis technique are not necessarily applicable to forward analyses using another technique."

Jan 1, 2016

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 M. Kannenberg

When coal properties are estimated geostatistically for mine planning in the hardcoal industry, there is one important supposition which influences the reliability of prediction of economically profitable parts of the deposit. This is the fact that activities in hardcoal exploration and mine planning are characterized by distinct levels of information and knowledge upon which decisions of economic import must be based, for example, whether exploration should proceed or not, or which methods and strategies should be used to maximize search efficiency. To get more reliable results for mine planning, in particular, advanced kriging methods (e.g. conditional simulation) have to be introduced and checked for their reliability in historical analyses (post-mortem studies). By using this feedback, kriging results from underground samples or production data can be compared with results gained by advanced geostatistical methods from exploration boreholes.

Jan 1, 1987