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By A. J. Vietti

"Drought conditions and the possible lack of sufficient raw water supply are a constant reminder to the Southern African diamond miner of the need to minimize raw (new) water input while maintaining or expanding mine throughput.Since water input volume is directly related to water output (loss) volume, mainly to the tailings, it is obviously beneficial to dewater the tailings as much as possible. However, this may not always be as easily achieved as first thought. Owing to the unique mineralogy of each kimberlite deposit and the unique chemical profile of each raw water source, dewatering of the slurry is not a standard process that can be applied equally across the entire diamond industry.This paper presents a first-step strategy that kimberlite diamond mine operators should consider and apply to meet and exceed their watersaving targets. Introduction A common metric for measuring water use efficiency in a metallurgical plant is the amount of raw water used per ton of head feed treated (m3/t). The metric includes all water recycled from the dewatering process and from the tailings storage facility (TSF), and the only inputs are tons of ROM ore and cubic metres of raw water make-up to replace water lost to evaporation, seepage, and lock-up at the TSF (Figure 1).The volume of new raw water available to the process is not unlimited and a maximum monthly allowance is typically set during the mine permitting process. Consequently, if the volume of water lost exceeds the volume of new water available or alternatively, in times of drought where the allowable volume is unavailable, the plant has no other option but to reduce throughput.However, if the plant operator is able reduce the volume of water lost to the TSF, the plant will have additional capacity to either increase tonnage throughput or sustain nameplate capacity during periods of severe drought. The obvious conclusion, therefore, is to reduce the volume of water lost to the tailings by improving the efficiency of the dewatering process (typically gravity thickening) simply by increasing the density of the tailings being discharged. In practice, however, the unique mineralogy of each kimberlite deposit and the chemical profile of the raw water source used imply that at some mine sites, solid/liquid separation (or settling) of tailings slurries at the dewatering process is more easily achieved than at others. In these cases, simple practical steps such as firstly improving the flocculant reagent make-up and dosing control, and secondly focusing on thickener discharge control, are the only requirements for enhancing water recovery at the dewatering circuit. At other mine sites however, solid/liquid separation of the tailings may not be achieved at all, in which case efforts to increase water recovery by improving reagent dosage and thickener control would be fruitless unless the colloidal properties of the thickener feed slurry are modified."

Feb 1, 2019

By R. P. King

The ideas leading to the formulation and utilization of a flotation model are developed. The main theoretical and experimental work that has been carried out by the National Institute for Metallurgy Research Group at the University of Natal is presented. The two experimental flotation plants available to this Group are described.

The 87th Annual General Meeting of the South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on Wednesday, 15th August, 1984. Professor R.P. King (President) was in the chair, and declared the meeting open at 16h00.

Jan 1, 1984

By G. Matheron

This paper discusses important aspects, both psychological and methodological, which have delayed the introduction of geostatistics in practice. The evolution of geostatistics is traced through three 'generations', and in conclusion some important questions are raised on the current status of the subject and possible areas of future research.

Jan 1, 1987

By R. T. Rudd

The impact of slimes-dam formation on water quality and pollution by R. T. RUDD*, B.Sc., AMI (S.A.) CE (Visitor) This paper discusses the mechanics of pollution by slimes dams in the gold- and fluorspar-mining industry, as well as that caused by coal dumps and slurry dams. The effect of coal mining on two typical rivers in Natal is shown and the implications discussed. The implications and trends of sulphates pollution on the Rand Water Barrage in the Vaal River are discussed. The spread of pollutants (sulphates and fluorides) from the Reef and elsewhere, and the impact on urban use and agriculture downstream of the barrage, are illustrated. Conclusions and future policy are outlined.

Jan 12, 1973

By A. Mitchell

On 25 August 2011, Andrew Mitchell, Lucas Moalusi, and Matthew van der Want of Bell Dewar hosted a presentation on Mining and Communities in Mooinooi, in the North-West Province. The conference was attended by traditional leaders in the North-West Province, officials from the Department of Local Government and Traditional Affairs, and executives from the mining industry. The presentation concerned traditional governance in mining, communities? rights in terms of applicable legislation, and the corporatization of community affairs.

Jan 1, 2012

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 M. J. U. T. Van Wijngaarden, R. J. Dippenaar, P. M. Van Den Heever

Some of the important properties of solid electrolytes that influence the performance of electrochemical oxygen probes are discussed in the first part of this paper. It is shown that accurate and reproducible measurements of oxygen in liquid steel are possible with commercial oxygen probes only if great care is exercised in the make-up of the chemical and phase composition, as well as the microstructure of the solid electrolytes used in these probes. To prove this premise, the second part of this study reports on the results of an experimental evaluation of new commercially available oxygen probe. An evaluation of the solid electrolytes used in this probe indicated that the consistency of the chemical composition, degree of stabilization, and microstructure of the electrolytes used are well controlled. The successful application of this particular oxygen probe under industrial conditions was confirmed. It was also found possible to make reliable and reproducible measurements, with acceptable uncertainty, by proper handling of the probe. Some recommendations are made as to the interpretation of the e.m.f. response curve and the use of the electronic processing unit supplied with the probe.

Jan 1, 1987

By H. D. Mtegha

The Southern African Development Community (SADC) aims to harmonize mineral policies and regulatory regimes in the minerals sector. This paper provides a review of the progress made towards harmonization of mineral regimes in the region. It singles out only the mining fiscal environment, as this is normally one of the key issues of interest to potential investors as well as the host state. Indications are that the region is slowly progressing towards a more harmonized approach, and there is evidence that the ?race to the bottom? has been prevented, which is the basis for an integrated mineral sector that the region aspires to.

Jan 1, 2011

By L. Wade

Laboratory testing of the self-heating propensity of coal, using crossing-point temperature and differential thermal analysis techniques, involves the frequent recording of several temperatures. The volume of data and the desire for high accuracy of measurements motivates an automated recording system. The data which are recorded must be adjusted for calibration factors and the results presented in both graphical and tabular form. The paper describes hardware and software features of a computerised system which is being used to establish the relative propensity to self-heating of a wide variety of coals.

Jan 1, 1987

By M. M. Oosterveld

Diamonds are mined from ancient raised beach deposits in southern Namibia where complex geological controls have resulted in patchy diamond distribution, largely related to irregularities (trapsites) in the bedrock. The distribution of the number of diamonds per sample is a discrete, reverse- J shape distribution which can be characterized by two parameters. These parameters have been transformed into a Beta and Theta Contribution which can be interpreted as reflecting the 'quantity' and 'quality' of the trapsites. The relationship of statistical parameters, obtained during the sampling of an ore deposit, to the geology of the deposit is an important element of ore reserve estimation. The large-scale regional trends in the contributions have been explained in terms of the geology.

Jan 1, 1987

By G. Whittle

An important aspect of the project evaluation process is the achievement of a clear and quantitative understanding of the primary drivers influencing project value and risk. A business scenario-based approach is required to ensure that the project meets value and risk hurdles over the short, medium and longer term. Adopting an optimising approach can aid significantly in the development of a project concept into a business that is optimal and sustainable in the longer term. Through the application of case studies, based on work performed with various mining organisations during the last five years, this paper will demonstrate how project value and robustness can be optimised. Experience has demonstrated that applying this approach results in significant value improvements and risk reduction - primarily by application of a rigorous, fact-based analysis and optimisation process that rapidly increases management team understanding and insight of key driver of value and risk.

Jan 1, 2007

By Stephen Hughes

Ausmelt Top Submerged Lancing (TSL) Technology has gained widespread commercial acceptance in the lead and zinc industries, as an efficient and highly flexible pyrometallurgical reactor with accompanying excellent environmental performance. For the processing of lead and zinc bearing feed materials twenty one (21) Ausmelt furnaces are now in operation, under design or under construction. With recent increases in the value of both lead and zinc and an ever increasing focus on the sustainable use of resources, interest in the processing of secondary feed material sources as well as metal containing residues has substantially increased. Ausmelt Technology has proven to be well suited to the economic recovery of values from such sources. This has for example culminated in Ausmelt?s commitment to the Whyalla Zinc project as the owner/operator of a facility for the treatment of zinc bearing secondary feeds. This paper describes Ausmelt?s recent developments in the fields of lead and zinc processing, as well as further investigations into new processing areas, including the direct smelting of zinc concentrates. Ausmelt?s TSL Technology can now be regarded as Best Available Technology (BAT) for metal production.

Jan 1, 2008

By P. J. Petit

The strategic mission of the South African mining industry is to extract the mineral assets in an energy efficient, economical and safe manner. Drilling has received particular attention in the last few years. As the operations move away from the power source, conventional and old drilling technology result in poor penetration rates, increased drilling shift lengths, slow face advances and limited stope efficiencies. The need for an alternate mining method, performed by a skilled workforce, to increase productivity, has led to the development of the electric rock drilling system for in-stope mining operations. The focus of this paper is a systematic evaluation of the electric rock drilling system as a function of production and technical parameters, in the platinum orebody. The particular electrical reticulation system is illustrated. Power usage, problems experienced, and solutions are described. The safe use of the recently developed drill is elaborated upon by describing protection devices. The testing and certification process, for approval by the recognized authorities, are documented. The testing and certification process, for approval by the recognized authorities, are documented. The human factor is also considered. Known detrimental factors of high noise exposure, vibrations levels and oil emissions are reviewed. In conclusion, recommendations on future strategies for the implementation of electric drilling technology within the mining and construction industries, is included.

Jan 1, 2006

By Anthony K. Anyimadu, Chris M. Rule

Froth flotation is the primary mineral processing separation step employed in the beneficiation of PGM ore bodies. Anglo Platinum operates a significant portion of the total installed flotation capacity in the PGM industry, which is installed at 20 operating plants across the Bushveld. PGM flotation has undergone a considerable evolution in both the capacity of flotation cells employed as well as in the circuit design configuration over the past thirty years. Certain of Anglo Platinum?s flotation circuits have been in operation for a relatively long period of time, (in some operations installed equipment dates from the 1960?s) and this allows comparative operating performance between various equipment types and circuits to be evaluated. This paper summarizes some aspects of this experience. Research trends in flotation are continuously monitored to incorporate appropriate findings into existing and future circuit designs. Continuous evaluation and monitoring of flotation performance is undertaken to identify opportunities for increasing flotation efficiencies. Mineralogical and fractional analyses of plant composites and survey samples are analysed to interrogate speciation and association data. This analysis has enabled a better understanding of priorities and opportunities for improved metallurgical performance. These opportunities are divided into three improvement areas: stability, liberation, and fines flotation. The paper discusses these, as well as the circuit design improvements required to take full advantage of the opportunities identified.

Jan 1, 2007

By V-P. Takalo, M. Natsvlishvili, M. Hicks, S. Khizanishvili

"The complexity of copper-gold ores leads to large variations in recoveries and concentrate grades in the processing plant. Detailed chemical and mineralogical studies revealed considerable variation in the ratios of chalcopyrite, chalcocite, and oxidized copper minerals in the ore types studied. The end-member ore types are chalcopyrite-dominated and chalcocite-dominated, while most of the ore types plot between these end-members. In addition, increasing amounts of copper oxide and sulphate minerals result in a decreased response to flotation. Good recoveries and concentrate grades can be achieved from the chalcopyritedominated ore type, while the more altered chalcocite-dominated ore type is more challenging to enrich. IntroductionRich Metals Group (RMG) Copper in Georgia (Figure 1) produces copper-gold concentrates from two open pit mines, Madneuli and Sakdrisi, both located in the Bolnisi mining district in South Georgia. RMG and Outotec began a cooperative project with the aim of improving the recoveries and metal grades in concentrate by gaining an increased understanding of the ore variability and developing more efficient procedures for ore blending, grinding, and flotation. This type of mineralogy-led approach has already been used for other complex ores such as iron oxide copper-gold ores (Hunt, Berry, and Bradshaw, 2011), for iron ores (Lund, Lamberg, and Lindberg, 2013), and for Kupferschiefer ore deposits (Rahfeld et al., 2018).The project started with process audits and mineralogical and chemical characterization of process samples, followed by detailed chemical and mineralogical characterization of six different ore types with simultaneous flotation test work on the same samples. Since neither the recoveries nor the concentrate grades correlate with the head grades of the ores, the modal mineralogical composition, together with the ore hardness, proved to be the most promising approach in developing the geometallurgical classification of these ore types."

Apr 1, 2019

By M. J. Kanda

"The design of rock slopes in the planning and operation of open pit mines and for road and rail cuttings requires the evaluation of their stability. This is commonly done using two well-established methods – limit equilibrium and numerical modelling. The research described in this paper compares the outputs of analyses using these two methods with regard to factor of safety and probability of failure, taking into account technical factors associated with each method and other factors such as material parameters and their variabilities. Results show that technical factors such as number of slices and slip circles, number and type of finite elements, and the stress reduction factor can all affect the results of stability analyses. Factors not taken into account in limit equilibrium analyses, such as dilation, in situ stress, and locked-in stresses can affect the outputs significantly. The research has focused particularly on the predicted location of the failure surface, the resulting volume of failure and, most significantly dependent on this volume, the predicted risk associated with slope failure. The results presented show that there is good agreement between the outputs of the two methods regarding factor of safety and probability of failure. However, the same is not the case with regard to volume of failure and hence risk, which can be very dependent on the methods of analysis and their input parameters. The research is not exhaustive, and there are many other factors that could affect the results of slope stability analyses that were not investigated. Some such factors are mentioned in the paper.IntroductionThe design of rock slopes in the planning and operation of open pit mines and for road and rail cuttings requires the evaluation of their stability. The traditional method of stability analysis used limit equilibrium (LE) methods, and this approach continues to be used. Numerical modelling (NM) packages are now also commonly used in slope stability analyses. The outputs from these analyses provide the factor of safety (FOS) and probability of failure (POF) of the slope. Since the capabilities of the two approaches are different, there can be some variations in FOS and POF outputs and in the predicted location of the failure surface. These variations can affect the predicted volume of failure, and this could in turn have a significant effect on the risk associated with the potential failure (Read and Stacey, 2009). Researchers such as Chiwaye and Stacey (2010) have found that LE analyses underestimate the predicted failure volume, unlike NM methods."

Jan 1, 2016

For the past 12 years, the Universities of Stellenbosch and Cape Town have hosted an annual symposium to discuss research topics in Minerals Processing. Since 1987, this meeting has been held under the auspices of the Western Cape Branch of the South African Institute of Mining and Metallurgy, and has enjoyed much national and international support. In 1993, in place of the usual Symposium, the Branch and Universities collaborated with CSM Associates Ltd and Minerals Engineering Journal is organizing the international Minerals Engineering '93 Conference in Cape Town.

Jan 1, 1993

By P. Beukes, D. Bessinger, R. Glenewinkel

High titania slag is produced by the smelting of ilmenite and a suitable carbonaceous reductant in electric furnaces. Currently liquid slag is cast into large blocks, which take about 10 days to cool down before they can be crushed, milled and classified into two final products. The two products, chloride and sulphate grade slag, are differentiated according to their size. Granulation of titania slag has been identified as a possible alternative to the conventional block route. This paper discusses some of the work carried out at Exxaro Research and Development to investigate both wet and dry granulation of titania slag.

Jan 1, 2007

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