Search Documents

The role of research and development In the South African gold-mining industry Presidential Address given by M. D. G. SALAMON, Fellow, Dipl. Eng. (Mining) (Hungary), Ph.D. (Durham) The decision of the gold-mining industry in 1974 to embark on a major ten-year research and development programme was widely publicized at the time. In choosing a subject for this address, I felt almost obliged to use this opportunity to give an account of the progress of this undertaking. On reflection, however, I felt that a simple progress report would not suffice. It seemed important that the programme should be shown in persepective, and that its aims should be outlined to the mining and metallurgical engineering community, many of whom are vitally concerned with the well-being of the gold-mining industry.

Jan 10, 1976

By L. Stamenov, A. Grigoryan, M. Nolte, E. Ayvazov, K. Evtiminova

Dundee Precious Metals Inc. (DPM) owns and operates the Ada Tepe gold mine and processing facility (previously referred to as the Krumovgrad Gold Project) located in south-western Bulgaria. The Ada Tepe mine became the first green filed project in past 40 year in Balkans and one of the few in Europe when it was commissioned during the first half of 2019. The plant produces a high-grade gold silicate concentrate generated through its comminution circuit and staged floatation reactors (SFR’s) while depositing its tailings in a state-of-the-art Integrated Mine Waste Facility (IMWF). This paper presents the successful commissioning, ramp-up and optimization of the Ada Tepe processing plant and how the various challenges, including that of an inexperienced front-line workforce, were overcome. More specifically addressing how the implemented modern processing technologies and the operational readiness program, supported the people and process to achieve the design parameters safely and consistently. Keywords: Commissioning, Optimization, Innovation, Gold mine, Digital mine

Jan 1, 2020

An International Ferro-alloys Congress, arranged by the Ferro Alloy Producers' Association of South Africa, the South African Institute of Mining and Metallurgy, and the National Institute for Metallurgy, will be held in Johannesburg, South Africa, in April 1974. The technical programme, occupying five days, will cover the following topics in relation to all ferro-alloys: 1. Burden preparation, blending, pelletization, handling, reducing agents. 2. Electric smelting furnaces-design, operation, management,- smelting optimization, shop practice, refractories. 3. Mineralogy, reduction behaviour, smelting reactions, slags. 4. Automation, Pollution control. 5. Applications, trends in comsumption, trends in composition specifications. There will be no parallel sessions. Papers in the above topics are invited; review papers will also be welcome. Proposed titles and abstracts in not more than 200 words should be submitted before the 30th of November, 1972, to The Chairman, Programme Committee, INFACON 74, Private Bag 7, AUCKLAND PARK, South Africa. The abstracts will be considered during January 1973, and papers accepted for the Congress must be submitted in final form before the 31st of July, 1973. The proceedings of the Congress will be published as a special volume. There will be a series of post-Congress tours to ferroalloy plants and other places of both technical and scenic interest. A full ladies' programme will be arranged. The First Circular, giving further details, can be obtained from: The Secretary of the Organizing Committee, INFACON 74, Private Bag 7, AUCKLAND PARK, South Africa.

By Alexandra Amiel

Tarkwa Gold Mine is owned by Gold Fields Ghana, IAMGOLD and the Government of the Republic of Ghana in a 71%, 19% and 10% ratio. The mine is operated by Gold Fields Ghana. This large, low-grade, open pit, gold mining operation is located in Tarkwa, in the Western Region of Ghana, approximately 320 kilometres by road, west of Accra, the capital of Ghana, West Africa. In the Financial year ended June 2007, the operation mined a total of 108 million tonnes of which 22 million tonnes was ore. The mined ore is processed through three gyratory crushers supplying two heap leach pads (North and South) and a carbon-in-leach (CIL) plant. Before the 6 Sigma project commenced, the current fragmentation was resulting in sub-optimal feed size to these crushers. It was decided to use 6 Sigma methodology to improve the fragmentation. A defect was defined as a fragmentation analysis indicating less than 95% passing 750 mm. The objective was to improve fragmentation in order to achieve a constant throughput to the north heap leach crusher of 1500 t/hr, a 5% increase in pit loading efficiency and a 50% decrease in rock breaker hours, equipment damage costs and in-pit sheeting costs respectively. However, this was not to be achieved at the expense of grade control as Tarkwa is exploiting a low grade, high volume deposit and therefore ore dilution must be kept to a minimum. This paper is intended to take the reader through the various 6 Sigma phases of the project (Define ? Measure ? Analyse ? Improve ? Control) which have resulted in a 10% reduction in loading times, of which half has been attributed to improved fragmentation, as well as a substantial increase in blasted stocks. The focus has been on both drilling and blasting parameters as both processes had to be taken into account. These parameters are technical but personnel factors were also identified and dealt with as they arose. In order to measure the impact of any change in the process parameters on the fragmentation size distribution, cameras have been acquired. One has been installed looking into the bowl of the north crusher and the other one was dedicated to field observation, of individual blasts. Both are used for on-going fragmentation analysis. At Tarkwa, mining efficiency is strongly dependent on good fragmentation as well as the presence of un-blasted ?toes? on the pit floors. Crusher throughput depends on an acceptable ore fragment size. Compliance to plan with regards to actual hole depths was temporarily monitored by manual hole dipping, but, this is now being replaced with a fully automated Drill Data Management system developed by Sandvik and Modular Mining. The Six Sigma methodologies, using control charts based on data collected in the field, allowed the mine to improve methods with regards to the control of blasted material. It also enforced the implementation of a quality control programme encompassing the entire Drill and Blast process.

Jan 1, 2008

By M. W. Hildyard, J. A. L. Napier

The improved design of support systems and stoping strategies when changes in depth, stratigraphy, or mine layouts are considered must rely on the designer's fundamental understanding of the deformation mechanisms adjacent to underground openings so that he can extrapolate and predict expected mining conditions. This paper presents a numerical approach to the modeling of the growth and interaction of mining-induced fractures near the edges of deep tabular excavations in brittle rock. Fractures are represented by displacement-discontinuity elements that are allowed to propagate according to prescribed growth rules. This procedure is justified by the reproduction of several features observed in laboratory simulations of fracturing around openings in blocks of rock subjected to uniaxial and biaxial compression. An attempt is then made to explain some of the attributes of the fracture zone surrounding tabular stopes. Particular questions of interest are the sequence in which fractures form and are mobilized in front of the mining face, the effect of parting planes parallel to the plane of the excavation, and the distribution of stress parallel to the hangingwall and footwall.

Jan 1, 1992

By M. Pawlik, N. Ghaffari Touran

The interactions between apatite and hematite were studied through zeta potential and stability experiments, for this paper. The zeta potential measurements were conducted in both background electrolyte and mineral supernatants. The difference in electrokinetic properties of minerals in the presence and absence of supernatant was explained in terms of the dissolution of minerals and the subsequent readsorption of dissolved species at the mineral-water interface. The stability measurements in individual and mixed mineral systems were also performed to identify the extent of interaction between apatite and hematite upon their direct contact. The results from stability measurements in individual and mixed mineral systems indicate that there is an interaction between apatite and hematite. Based on the results, the implications for the apatite-hematite separation process were discussed. Keywords: Apatite, hematite, dissolved ions, stability, zeta potential

Jan 1, 2020

By M. J. Deats

Your article on page 202 of the August 1993 Journal refers. I was surprised to read that this grant was first introduced in 1984 as it was awarded to me (albeit under the auspices of The Institution of Mining and Metallurgy, London) as long ago as 1964, and I spent two very profitable months in Sweden at that time. Training in job-skills * A South African mine is leading the way in providing alternative job-skills to staff in a bid to upgrade services in local communities and create greater economic empowerment. In recent months, 85 employees of the Associated Manganese Mine (ASSMANG) in the Western Cape have learnt skills as diverse as candlemaking, shoemaking, concrete-product manufacturing, and brick production through a newly established community training centre.

Jan 1, 1993

By I. Druce, C. Li, T. Qu, J. Dong, W. Y. Xinchao, V. Nkuna

CITIC Heavy Industries has a large installed base of grinding equipment throughout Africa in different configurations, including high-pressure grinding rollers with ball mill and semi-autogenous ball crusher. The total installed power of CITIC’s mills exceeds 430 MW. In this paper, we compare several typical grinding circuits of copper in Africa with about 15 kt/d throughput based on ore properties, process selection, equipment sizing, and key equipment capital and operating costs. Actual operating performance is also introduced. The comparison for the following mine sites provides a general reference for the selection of copper grinding circuits with this approximate throughput: Kamoa-Kakula Copper Mine with high-pressure grinding rollers with ball mill circuit, and Deziwa and Sicomine Copper-Cobalt Mines with semi-autogenous ball crusher circuits

Jan 1, 2023

By U. König, N. Norberg

Ore mineralogy defines the properties during processing and metal extraction. Fast and frequent monitoring of the mineral content and related process parameters brings value to the mining operation and material processing. Decreasing ore qualities and increasing prices for raw materials require a better control of processed ore and a more efficient use of energy. Traditionally quality control in mining industries has relied on time consuming wet chemistry or the analysis of the elemental composition. The mineralogy that defines the physical properties is often monitored infrequently, if at all. The use of highspeed detectors has turned X-ray diffraction (XRD) into an important tool for fast and accurate process control. XRD data and their interpretation make the difference in the identification of minerals, in describing their distribution in ore bodies and in their beneficiation during processing. The use of statistical techniques such as Partial Least-Squares Regression (PLSR) or Principal Component Analysis (PCA) on XRD raw data has been successfully trialled to determine raw materials and processed ores, in addition to well established methods for mineral identification and quantification. PLSR can be used to correlate process parameters directly from the XRD pattern without investigating the mineral content. Hidden information present in the XRD pattern but not determined with traditional methods can be used to improve the characterisation of the analysed materials. The practical use for the direct determination of process relevant parameters during exploration and ore beneficiation will be illustrated in several case studies from mining and ore processing. Keywords: Geometallurgy, mineral monitoring, X-ray diffraction, process efficiency

Jan 1, 2020

Balance Sheet at 30 June 1990 ACCUMULATED FUNDS Balance at 30 June I989 . Excess of income over expenditure for the year ended 30 June 1990

Jan 1, 1990

Letter to the Editor With reference to the recent questionnaire in the December 1980 issue on 'The Contents of Journals', I have made the following observations.

Jan 1, 1981

By T. Steyn, M. Fofana

"One of the most important performance indicators of a dense medium cyclone (DMC) circuit is the Tromp curve, and by extension the separation density and Ecart Probable (Ep) values. The densimetric profiles of DMC product streams have been traditionally acquired using heavy liquid sinkfloat analysis, which has certain disadvantages, such as the associated safety and health risks. More recently, non-toxic media such as lithium hetero-polytungstates (LST) have been used, with the desired densities being achieved by maintaining the solutions at specific temperatures. However, the high costs of these liquids can be prohibitive. The long turnaround time of the sink-float analysis is a further disadvantage for timeous interventions to the operating set-points of the DMC process.The RhoVol technology can generate the density distribution of a batch of particles in a rapid, accurate, repeatable, and safe manner. Additional data of interest, such as particle size and shape, are also measured and reported on a per-particle basis. Furthermore, samples can be sorted into discrete sorting bins based on any of the measured parameters of the particle, making further analyses of the material possible.This technology has applications across all commodities that use the DMC, particularly in the size fractions –25 +8 mm and –8 +3 mm. To date, laboratory results have proved very encouraging – separation densities are within 5% of traditional sink-float results, and the technology is being introduced to diamond DMC plants. IntroductionDense medium separation is a commonly applied beneficiation technique for the density separation of valuable products from crushed ores. The industrial applications of dense medium separation have been summarized and reviewed by various authors (Scott and Napier-Munn, 2000; Bosman, 2014; Napier- Munn, 2018). Dense medium cyclones (DMCs) are widely used in the coal and diamond industries to produce clean coal or to preconcentrate kimberlitic ores, respectively. Cyclone performance (separation density monitoring) techniques are varied. In the mineral industry. Density tracer tests (Napier- Munn, 1985, 2014; Davis, Wood, and Lyman, 1985) without mineral material, are widely used, although their accuracy in predicting operating cut-points becomes limited once mineral material is introduced. More recently, radio frequency tracers have been also used for the determination of cyclone efficiency (Partition Enterprises, 2017)."

Feb 1, 2019

The Canadian Institute of Mining and Metallurgy. Milling practice in Canada. CIM Special Volume 16. 1978. The purpose of this volume is to up-date The Milling of Canadian Ores, which describes Canadian mineral. processing plants and gives other metallurgical information, and was published by the Sixth Commonwealth Mining and Metallurgical Congress in 1957. NIM reports Report no. 1874 Activation analysis and classification to soune of samples from the Kimberley Reef conglomerates. (10th Mar., 1977; released Jun. 1978). Report no. 1926 The analysis of anode sludges by X-ray-fluorescence spectrometry. (5th Jun., 1978). Report no. 1936 The analysis of mineralogical and metallurgical materials. A guide to the analytical techniques and instrumentation available at the National Institute for Metallurgy. Report no. 1959 The slag-metal equilibrium, and the activities of slag and metal components in the production of high-carbon ferromanganese. (15th May, 1978). Report no. 1965 Analyses, by several laboratories, of three ferromanganese slags. (22nd May, 1978). Report no. 1968 The influence of carbonaceous reducing agents on the rate of reduction of representative manganese and chromium ores. (28th May, 1978). Company Affiliates Guide To The Preparation Of Papers for Publication In The Journal Of The South African Institute Of Mining And Metallurgy The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal.

Jan 1, 1979

By F. Dutoy, M. B. Stella, C. F. Carrozza

Rare earth elements (REEs) are indispensable components in the manufacturing of high-tech devices, renewable energy technologies, and defence applications. As global demand for these elements continues to rise, there is a pressing need to optimize extraction processes for both efficiency and environmental sustainability. This study explores approaches to rare earth extraction using Ionquest® 801 and integrates a predictive modelling to enhance process understanding and optimization. We conducted a screening test varying pH process to evaluate the best extraction efficiency. Starting pregnant leach solution (PLS), solution was prepared in the lab with the following rare earth elements: La, Ce, Gd, Dy, and Υ, at 0.02 M for each element. The data obtained were used to develop empirical and mechanistic models to predict rare earth extraction yields and flowsheet. Further tests were performed by mixing specific concentrations of different extractant and/or phase modifier. Our experimental results demonstrated the effectiveness of the proposedextraction methods, highlighting improvements in both yield and selectivity. The developedmodels successfully captured the complex relationships between process parameters and extraction efficiency, providing valuable insights for process optimization.

Nov 6, 2024

By C. Birch

"Mineral reserve statements as well as optimizing mine planning require a block model with grades for each mining block. A cut-off grade is determined by considering the mining costs as well as the expected revenue for each block. These grades are estimated using various techniques, but in reality there is uncertainty in the grade values. These uncertainties result in two types of error. A type I error is where material is classified as ore and mined, but the true value is below the cut-off grade and the material is therefore waste. This material constitutes dilution. The type II error is where material is estimated to be below the cut-off grade and is classified as waste, whereas the true grade is actually above the cut-off grade. This material is not mined and the value is lost.This research considers the value of the lost ore and the costs of dilution under various degrees of uncertainty. Simulation using @Risk and mixed integer linear programing (Excel Solver) is used in a financial optimizer model to maximize either profit or net present value. This is applied to four Witwatersrand tabular gold deposits to investigate the impact of block grade uncertainty on cut-off grades.When optimizing for profit, value may be added by adjusting the cutoff grade slightly downwards. When optimizing for NPV, value may be added by lowering the cut-off grade significantly for the lower discounting rates. At higher discount rates, the lowering of the cut-off grades should be reduced, and in some cases an increase in cut-off grade may be required. Each mine reacted differently to the optimization and thus there is no single rule that can be applied across all tabular Witwatersrand gold deposits."

Jan 1, 2017

By M. -B. Kime

This study applies attainable region analysis to optimise cobalt recovery from oxidised ores via reductive leaching with sulphur dioxide and sulphuric acid. The attainable region framework enables systematic visualisation of trade-offs between cobalt yield and sulphur dioxide loss, guiding reactor network design beyond conventional mass balance modelling. Experimental column leaching trials, supported by validation runs, were conducted under controlled flow and reagent conditions. Kinetic parameters for cobalt dissolution and sulphur dioxide consumption were used to simulate reactor trajectories and construct attainable region envelopes. To ensure hydrodynamic realism, residence time distribution tests confirmed partial plug flow behaviour with dispersion effects, justifying the use of hybrid reactor models in the attainable region simulations. The results revealed that increasing recirculation ratios improves cobalt yield while reducing sulphur dioxide losses, with attainable efficiencies exceeding 90% cobalt recovery and < 20% sulphur dioxide loss. Importantly, the study proposes practical reactor network configurations for future implementation, including staged percolation columns with intermediate mixing zones, oscillatory flow reactors, and modular fluidised bed systems. These designs offer scalable pathways to translate attainable region-based optimisations into industrial practice. Compared to traditional modelling, attainable region analysis provides a geometric decision support tool that captures multi-objective trade-offs and reactor interactions, offering novel insights for continuous leaching system design. This work advances the application of attainable region methodology in minerals engineering by bridging theoretical optimisation with practical reactor design, supporting sustainable cobalt recovery from both primary ores and recycled feedstocks.

Mar 30, 2026

By E. Saari, B. Musuku, K. Jansson

The quality of the concentrator plant process water is crucial for high performing mineral flotation circuits. Significant metal recovery and concentrate grade losses have been noticed particularly in more closed water loops. The recovery and quality losses have started to emerge mainly with decreased freshwater usage and because of changes in tailings management towards tailings thickening, paste, or dry stacking. These changes result in shorter, closed water loops with a rapid build-up of harmful components with negative impact on the beneficiation process. Consequently, water quality has a direct link to decreased product value and sales returns. Complete cleaning or water blending might not be the right way to achieve high recovery and high-quality products. Instead, the key is to understand what kind of water qualities are needed for the flotation of specific minerals. In this study harmful substances in various plant water streams were removed and/or modified by pilot-scale dissolved air flotation. Batch-scale mineral flotation tests with the untreated and treated water were then performed by using fresh ore samples and the plant’s own laboratory flotation procedure. The results indicate that because of dissolved air flotation, the mineral flotation recoveries were enhanced by 1‒3.3%. Keywords: Mineral recovery, metal recovery, mineral quality, process water, concentrator, beneficiation, mineral processing, flotation, process water treatment

Jan 1, 2020

By G. Akdogan, T. P. Kekana, Q. G. Reynolds

The DC arc plasma gasifier concept is currently under development at Mintek for testing the feasibility of producing syngas from waste coal fines and dry steam. The technology is intended for the valorisation of low-grade discard coals into market-quality syngas, which may then be used for largescale electrical power generation to address current grid supply challenges in South Africa. Other potential applications include feedstock for petro-chemical plants, fuel for transportation vehicles, domestic and industrial heating, and others. The proposed concept of a DC arc plasma gasifier was developed based on a plasma torch, metallurgical-based and entrained flow coal gasifiers. The principles of design and operation of the proposed gasifier are based on the concept of the Westinghouse Plasma Corporation (WPC) gasifier where the torches are substituted by graphite electrodes from which electric arc plasmas are generated. The DC section of the gasifier will be designed considering Mintek’s experience in the sealing of the furnace as carried out in the Mintek Thermal Magnesium Process. As part of the building blocks of a full conceptual design, the feasibility of the DC arc plasma gasifier was investigated through testing and modelling of its critical elements as proof of concept. The main activities of this work included pilot scale evaluation of the arc behaviour in the presence of dry steam, modelling of the temperature distribution within the reactor and explosibility studies on three different coal dust samples. Keywords: DC arc plasma gasifier, explosibility index, lower explosion limit, minimum ignition energy

Jan 1, 2020

By M. Aatach, St. Gaydardzhiev, M. Kadiyski, E. Visariev, V. Stoilov

Detailed process oriented characterisation on representative samples from plant survey of the slag flotation plant belonging to Aurubis, Bulgaria has been realised in order to evaluate the mineralogical occurrences of Cu, Ni, Mo and Co bearing phases. The slag subjected to flotation consisted in majority of fayalite, magnetite-iron oxides and a glass-like phase. Ni and Mo have been found to be closely associated to magnetite and fayalite. The tailing from the slag flotation has been subjected to sulphation roasting followed by water leaching as a hydrometallurgical means to recover the remaining Cu, Mo, Ni and Co. Based on the various sulphation roasting conditions (acid dosage, duration, temperature) copper, nickel and cobalt were brought to solution to a different extent. Molybdenum was the most difficult to be rendered soluble due to its close association with iron, suspected to form an insoluble compound with it. Sulphation roasting performed at 350ºC has secured the best extraction degree for Cu, Mo and Co, while maximum recovery of Ni has been documented when roasting was done at 150°C. Keywords: Copper slag; characterisation; SEM; roasting; metals leaching, hydrometallurgy 16(2), 153–65.

Jan 1, 2020

By O. K. H. Sheff

An editorial in the April 1990 edition of Mining Magazine is worth a wider audience in South Africa, particularly as the SAIMM enters its own centenary decade and the process of change in the minerals industry world-wide makes increasing demands on the professionalism of its leaders. The editorial considers the changing status of engineers, who up to the 1880s had been held in high regard by society. Alumina and bauxite Economists forecast a slower economic growth rate in 1990, but expect continued increase in demand for aluminum at a 3 per cent annual rate during the decade. Structural and numerical analysis Struceng & Femcad (structural analysis and finiteelement method) is a conference and exhibition that is to be held in Grenoble (France) on 17th and 18th October, 1990. It is sponsored by the Institute for Industrial Technology Transfer (ITT-International).

Jan 1, 1990