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1. Book reviews Nonparametric geostatistics, by S. Henley. London, Applied Science Publishers, 1981. xiv + 145 pp. Reviewer: Douglas M. Hawkins Mineral deposits and global tectonic settings, by A. H. G. Mitchell and M. S. Garison. London, Academic Press, Geology Series, 198!. Reviewer: J. Lurie The mining and mineral laws of South Africa, by B. L. S. Franklin and M. Kaplan. Durban, Butterworths, 1982. Cloth, 240 X 150 mm, Lxxcii + 853 pp. R197,50 + GST. Reviewer: M. J. Martinson Aluminium- Volume II, by M. H. Govett and J. Larsen. Sydney, Australian Mineral Economics (Pty) Ltd, 1982. Reviewer: D. G. Maxwell International technology for the nonferrous smelting industry, by Noyes Data Corporation. Reviewer: D. A. Viljoen 2. New publications Coaltransport- an analysis of technical and economic factors, by Dag Pike. London, Financial Times, 1982. £86 (D.K.), D.S. $175 (overseas including first class airmail postage). Small solute concentration differences determined by interferometry, by H.E.L.G. Schweigart. Pretoria, CERG-CSIR (P.O. Box 395, Pretoria), 1982. 3. Mintek reports Report M8A determination, using solid zirconia electrolytes, of the activities of chromium oxide in ferrochromium alloys and slags at 1650°C. Report M31Software for the design of multivariable control systems by use of the Inverse Nyquist Array. Report M37A literature survey of the metallurgical aspects of minerals in Witwatersrand gold ores.This survey reviews the information in the literature Report M 39 The use of masking agents in the determination, by hydride generation and atomicabsorption spectrophotometry, of arsenic, antimony, selenium, tellurium, and bismuth in the presence of noble metals. Report M40 The use of X -ray-fluorescence spectrometry in the determination of uranium, cobalt, and sulphur in materials from mine dumps. Report M44 A n on-line dilution system for spectrometry ustng an inductively coupled plasma source. Report M47 The separation of trace elements from iron, and the analysis of iron-rock ores for use as reference materials. Report M49 A programme in BASIC for the appending of computer files. Australian coal The editors of World Coal and World Mining have announced plans to sponsor the IVth International Coal Exploration Symposium. The symposium will be held in Sydney (Australia) from 15th to 19th May, 1983. Small mine economics The editors of World Mining and World Coal have announced plans to sponsor the Second International Symposium on Small Mine Economics and Expansion in Helsinki, Finland, from 12th to 16th June, 1983. The first symposium was held in Taxco, Mexico, in May 1981.

Jan 1, 1982

By A. Y. Senchenkoa, Y. V. Kulikov

The relationships revealed between ore hardness and specific energy consumed by crushing and grinding are described in the paper. A comparison of key technical and economical parameters of SAG and HPGR circuits is made, based on testing of several ore types for greenfield projects. The comparison of results make it possible to estimate efficiency of the technologies application, depending on ore hardness and taking into account potential risks for a circuit under design. Keywords: Comminution circuits, SAG, HPGR, test results

Jan 1, 2020

By G. Bueno, L. M. Tavares, T. M. Campos

Iron ore pellet feed pressing has been one of the first and most successful applications of High- Pressure Grinding Rolls (HPGR) in the minerals industry. Vale S.A. has been one of the pioneers in this application, currently with six HPGRs in operation in the pelletising plants of the Complexo de Tubarão (Brazil). In spite of the important advances in the technology, risks still exist when scaling-up the process from small-scale information. The present work takes advantage of the recent advances in the mathematical modelling of the HPGR performance, using the population balance model to evaluate the modified Torres and Casali model prediction in iron ore pellet feed pressing for different scales of operation. Results are presented that compare the HPGR performance in different operational scales for iron ore pellet feed pressing, demonstrating the confidence of this model-based approach for scale-up to full-scale HPGRs used in pressing iron ore concentrates. Keywords: Scale-up, HPGR, pellet feed, modelling, simulation

Jan 1, 2020

By Y. Fan, D. H. Zhang, J. Y. Xu

The hydrogeological conditions in the Chambishi mine area in Zambia. were investigated. Chambishi is a very wet mine and groundwater discharge costs are high. The research goal was to identify methods to reduce the discharge costs without greatly affecting the mining process. Hydrogeological data was obtained from measurements in drill-holes and from drill cores. The differences in structural deformation in different areas determine whether a layer of rock is an aquifer. In the mine region, the Lower Roan Group ore shale and quartz-sandstone unconformably lie on the basal schist and granite aquifuge. The Upper Roan Group dolomite is continuously distributed over a large area around the orebody. This dolomite is the main target of groundwater control efforts, and its water yield is also influenced by the deformation intensity. Based on the observations, backfilling was gradually adopted to appropriately safeguard the integrity of the aquifuge above the orebody. The overlapping relationship between the aquifer and aquifuge has been utilized to increase mine drainage efficiency. This measure has not only greatly reduced the costs of mine drainage, but also improced protection of the groundwater environment. The old drill-holes that were not sealed after exploration drilling were grouted. Further, possible water-conducting fracture zones were investigated. Cover drilling towards the suspected zone was conducted to prevent the high-pressure groundwater from shallower aquifers from entering stopes in deep areas of the mine.

Jun 10, 2024

Newmont is one of the few remaining large mining companies that was established in the early nineteen hundreds. The company has a long, colourful and enviable history. This paper provides highlights of Newmont?s business and technical history since its inception in 1916, its transition to a ?gold only? company in the early 1990s and progress since that time up until the present day. Details of Newmonts current gold operations and its gold production profile for 2008 are also provided in the paper Over the last 50 years Newmont has developed a host of innovative gold technologies to meet the challenges of treating the complex refractory gold ores, found at the company owned mines in the Carlin region and around the world. Details of the technologies are provided and they include chlorination, roasting, bacterial and pressure leaching, leaching gold with thiosulphate and thiocyanate, N2Tech flotation, HPGR treatment of hard and abrasive ores and, finally, the use of Hydro-Jex technology for improving gold recovery from heaps.

Jan 1, 2009

By L. Tartibu, S. Assuli, P. Nkul, A. Kabimba, W. Elongo, N. Makhotla, D. F. Verwey, F. G. Ndiitwani, J. Bilali, T. Mukongo

The presence of colloidal silica negatively impacts various hydrometallurgy processes. This paper details the nature of colloidal silica, operational issues caused by colloidal silica, as well as various mitigation measures. MMG Kinsevere observed severe phase-continuity instability, increased crud formation, and reagent consumption, and reduced current efficiency in electrowinning with a deterioration in copper quality. Historical mitigation measures were initially implemented but failed to solve the problem. MMG Kinsevere successfully achieved efficient silica removal without adverse effect on the solvent extraction with the use of DEHSCOFIX® SC12 coagulant. A week into the coagulant trial, silica concentration had dropped from > 1500 mg/L to within 500 mg/L. The solventextraction plant recovered its stability and again operated at maximum capacity. Additionally, improvement was observed on current efficiency and copper cathodes quality with use of the coagulant.

Jan 1, 2023

Sedimentary Ores-Ancient and Modern (Revised), edited by C. H. James. Proceedings of the 15th Inter-University Geological Congress. University of Leicester, December, 1967. Special Publication No.1, Department of Geology, University of Leicester, February, 1969. Obtainable from: Leicester University Bookshop, May's Walk, Leicester LE 17 RD. Price: 42s. Postage and packing, 3s. 6d. This volume should be of interest to economic geologists and students in this field. A number of illustrated papers on the genesis of ores in sediments are presented; the authors include experts such as Prof G. C. Amstutz, Dr K. C. Dunham, Prof D. Williams and W. G. GarIick. The papers deal mainly with sulphide deposits, but the late Prof J. H. Taylor's contribution concerns ores of iron and manganese. Brief references to the Witwatersrand ores represent the only discussion of South African deposits. With the notable exception of W. G. Garlick's paper on Zambian copper deposits, the Abstracts given are inadequate, necessitating thorough reading of the papers to extract the important matter.

By Willem J. Marais

The management of unpaved mine road networks on large surface mines rarely results in optimal road maintenance strategies and minimised total road-user costs. This is ascribed mostly to the complex and dynamic combination of variable road networks and loading and discharge points. In a dynamic mining environment - typically those mines in which production is managed by a centralised truck dispatch system ? there is no guarantee that a particular road maintenance intervention will contribute significantly to reducing total road-user costs or increasing productivity. Most large surface mines operating ultra-heavy mine trucks rely on an integrated on-board diagnostic data collation, communication and GPS-asset location system as a real-time fleet management tool. By extending this system to incorporate a multi-sensor analytical procedure in which specific truck vital signs are monitored and filtered, a road defect can be recognised and a trigger level set to relay the location of defects on the mine haul road to the centralised truck data management system. Previous work established the feasibility of the multi-sensor approach to road defect recognition on large mine haul trucks, and outlined the defect recognition, analytical and modelling issues and system limitations. This paper presents the development of the analytical procedure used as a basis for evaluating the truck on-board data to establish maintenance priorities amongst a network of mine roads. Following an introduction to the system architecture, the results of system field trials are analysed and the results discussed in the light of defect density and traffic volume as the primary variables in an approach to prioritising road maintenance. The paper concludes that by supplementing the existing mine communication and asset management systems, road maintenance can be managed on a near real-time basis and maintenance equipment dispatched to where most immediate benefit will realised from a maintenance intervention on the network, thereby generating the maximum improvement in service and reduction in cost per ton hauled.

Jan 1, 2008

By E. D. Musin, S. S. Gudkov, A. V. Epiforov, S. V. Balikov

The standard technology for processing of gold-bearing sulfide raw material has many problems associated with the use of cyanide as a gold lixiviant. Therefore, many tests to find alternative gold recovery methods are being undertaken. This paper describes some technological solutions, which can become alternatives to cyanide technology in the future. Pressure oxidation (POX) of refractory gold-bearing sulfide concentrates from five different Russian gold deposits were investigated. Concentrate 1 was gold-copper concentrate. Concentrate 2 was gold-pyrite concentrate. Concentrates 3-5 were pyrite-arsenopyrite double refractory concentrates. The POX tests were at temperatures of 110, 200 and 220 °C and oxygen pressures of 1.5, 2.4 and 3.0 MPa were carried out. Gold lixiviants, such as chloride, thiosulfate, sulfite and thiocyanate were tested. The recovery of gold from sulfide gold-bearing concentrates by non-cyanide methods was 97- 99%, and from double refractory concentrates, 86-93%. The tested reagents are less toxic than cyanide, and their use will reduce of the cost of gold production. These methods make it possible to recover gold in acidic media, and eliminate the washing operation and POX slurry neutralisation. In addition, precious metals recovery from POX cakes using lead reduction smelting was investigated. It was shown that the “POX-pyrometallurgical” technology for double refractory concentrates processing could be used with recoveries of gold and silver of 97 and 96%, respectively. Keywords: Recovery of gold, refractory sulfide gold-bearing concentrates, double refractory concentrates, pressure oxidation, non-cyanide lixiviants of gold, chloride autoclave leaching, thiosulfate leaching, thiocyanate leaching, sulfite leaching, reduction smelting, POX-pyrometallurgical technology

Jan 1, 2020

It is well understood that to develop wagon wheels with higher abrasion resistance, fracture toughness, and fatigue resistance, steels with lower amounts of inclusions need to be used. Clean steels are produced with technologies that minimize the amount of inclusions in the microstructure. The demand for cleaner steels is high, and lowering of non-metallic oxide inclusions and controlling their morphology, composition, and size distribution is vital. Reduction of residual impurity elements such as sulphur, phosphorus, hydrogen, nitrogen, and trace elements is essential in the production of cleaner steel. Material cleanliness is vital for fatigue endurance, since oxide inclusions may act as stress concentrators and initiation points for fatigue cracks. To better understand the relationship between the cleanliness and toughness of the 34-inch cast wagon wheels, two samples of different levels of cleanliness were supplied for investigation. This paper presents the results of metallurgical analysis using scanning electron microscopy(SEM), energy-dispersive spectrometry (EDS), and mechanical tests for the pearlitic high-performance cast rail wagon wheel (identified as Class B) that are currently being used. The Charpy V-notch impact test results for the three samples from wagon wheels were compared. With the aid of SEM/EDS analysis system, non-metallic inclusions in these steels were detected, and it was possible to determine the position, size, shape, and composition of each particle. Alumina and manganese sulphide inclusions could be identified as the dominant inclusion types in the investigated samples. Fracture surface analysis of the Charpy specimen with high inclusions indicated that transgranular cleavage was the predominant fracture mode. Fractography of fracture surfaces of Charpy impact test samples also showed improvement of toughness properties on the clean sample.

Jan 1, 2013

For practical reasons all basic input data for the gold mines of the Anglovaal Group conform to a regular grid of averages of sample values within 25-ft squares in the plane of the ore body; individual sample values with their metric co-ordinates are input and converted by a computer program to the basic 25-ft square averages. At the Prieska copper mine the bore- hole data are forced on to a regular grid of 15-m squares corresponding to the coordinates of the grid points nearest to the actual borehole intersections. As for the gold mines the Prieska ore body, although some 3 to 30 m thick, is also dealt with on a two-dimensional basis (Krige, 1973). On the gold mines the data subjected to geostatistical analysis cover: gold values (in cm g/t), uranium values (cm kg/t), and channel widths (cm). The gold and uranium values are normalised on the basis of log (value plus constant) and all the geostatistical analyses are performed on these transformed values. The channel widths usually conform reasonably well to the normal distribution and are, therefore, not transformed. At Prieska the metal grades analysed cover the two main products, copper and zinc, as well as the impurities lead and bismuth; in addition the specific gravity values and the hanging- and foot-wall deviations from a projection plane are also handled. These were all previously used on an untransformed basis but because of problems associated with the proportional effect the lognormal-de Wijsian model is now used for some of the grade variables. The key computer pro- grams can be summarised briefly as follows:

Jan 1, 1981

By L. A. Cisternas, R. I. Jeldres, D. Calisaya

"Flotation of copper-molybdenum sulphide ores in seawater entails critical challenges such as selective recovery of molybdenite, effective pyrite depression, and reducing the lime addition required to reach highly alkaline conditions. It is essential that laboratory flotation tests aimed at solving these problems give reliable, reproducible results and indicate the correct approach for industrial operations. Rougher flotation of coppermolybdenum sulphide ores in seawater was investigated using two different cells: a modified Denver cell and a standard commercial cell. The effect of an organic reagent on the flotation performance was tested, and the fast/slow-floating model was used to describe the results. The modified Denver cell significantly improved the reproducibility of the flotation test results, due to technological enhancements such as the impeller being driven from below without a stator, which enables the whole froth surface to be scraped with a paddle at a constant depth and rate. Organic reagents are a promising alternative to inorganic reagents for depressing pyrite in seawater. However, further studies should be conducted to investigate their impact on molybdenite recovery, as well as to evaluate the possibility of depressing pyrite after molybdenite separation. The fast/slow-floating model was found to be appropriate for describing the flotation kinetics of the copper-molybdenum ores. The parameters are useful for comparing the performance at different conditions. IntroductionOwing to the increasing scarcity of fresh water, the use of seawater mining and mineral processing is becoming increasingly important (Cisternas and Moreno, 2014). Seawater can be desalinated by reverse osmosis, but this involves considerable costs, limiting it to the big mining companies (Akgul et al., 2008; Leidner et al., 2012; Ghaffour, Missimer, and Amy, 2013). Furthermore, desalination has environmental consequences (Lee, Arnot, and Mattia, 2011); for example, a desalination plant designed to process 2.5 m3/s requires an electrical energy supply of around 30 MJ/s. To supply this power demand, a thermoelectric plant burning bituminous/sub-bituminous coal mixtures at a thermal power generation efficiency of 35% might release around 1200– 1500 t of CO2 per day. Furthermore, the effluents from desalination plants are typically discharged into the sea, and their high temperature and ionic content inevitably modifies the marine environment, with unknown consequences. The direct use of seawater is, therefore, more attractive, but it also poses major challenges since seawater contains ions that adversely affect mineral recoveries. In particular, in the flotation of sulphide ores in seawater, the floatability of molybdenite is depressed (Castro, 2012; Laskowski, Castro, and Ramos, 2014)."

Jan 1, 2017

By B. Friedrich, A. Birich

Gold has been a metal of special importance for mankind for several thousand years. Its outstanding chemical resistance is an important property of this noble metal, but becomes a disadvantage when it comes to gold recovery. The established processes are based on highly aggressive and toxic reagents. Different alternative leaching reagents with a significantly lower toxicity proved to be promising alternatives in the last decades. Major research activities in this field focused on gold ores, so that leaching of secondary resources were not described sufficiently. Based on literature research and extensive experimental investigations, a reagent assessment was conducted for hydrometallurgical gold recovery from electronic waste. It was found that besides thiourea and halides, thiosulfate in particular represents an alternative of major relevance. A variety of different electronic waste (e-waste) specimens were investigated to identify suitable leaching conditions. As a result, an almost complete and selective gold recovery in less than 48 hours from different electronic waste types and components was achieved by thiosulfate leaching. Within the experiments conducted, it was found that the leaching behaviour of cyanide alternative lixiviants differ strongly from leaching of primary ores. Keywords: Gold leaching, cyanide alternative, thiosulfate, electronic waste

Jan 1, 2020

By H. Wagner

In 1980 The South African Institute of Mining and Metallurgy instituted the Brigadier Stokes Memorial Award to commemorate the outstanding contribution to the South African mining industry made by Brigadier R.S.G. Stokes, who was an Honorary Life Fellow and a Past President of the Institute.

Jan 1, 1986

By M. -A. de Ville d’Avray, J. Bosman, S. Brochot

Dense Medium Separation (DMS) technologies are used for light (coal, lithium) or heavy (chromite, iron ore, diamonds) minerals concentration, but also for ore pre-concentration (Pb/Zn) or waste (plastics). Dense media are mainly formed from a suspension of magnetite or ferrosilicon in water. Such DMS circuit design or optimisation requires a full and detailed material balance which can be obtained by the aid of modelling and simulation tools. This balance is not limited to ore and its valuable minerals, but also the recovery of the dense medium itself. If the density is the main property used for separation, the particle size plays a non-negligible role, and, more precisely, the liberation classes which can be associated to the washability curve. The paper presents how the modelling and simulation platform USIM PAC can answer this challenge with the set of models for DMS operating units such as drums or cyclones, and their associated screens (drainage, rinsing) and magnetic separators for medium recovery. Some examples for mineral concentration will illustrate this approach. Keywords: Process simulation, process modelling, dense medium separation, process optimisation

Jan 1, 2020

By G. P. O’Malley, A. N. Nikoloski

One of the most promising options for extraction of copper from low-grade chalcopyrite ores by heap leaching, however, chalcopyrite is refractory and suffers slow leaching kinetics and poor overall extraction due to formation of a passivation layer on the particles. The solution composition is believed to strongly affect the formation of this layer. This paper examines the effects of the major cationic species of Fe3+/2+, Mg2+, Cu2+, and Al3+ and the anionic SO42− species in acidic ferric sulfate media with a composition simulating recycle heap leach conditions. It was found that altering the sulfate, iron or aluminium concentration had significant effect on the copper extraction, the concentration of copper slightly influenced the extraction, and the amount of magnesium had no appreciable effect. Also, iron and aluminium caused a change in the sulfate concentration, and the sulfate ions had the greatest influence on the extraction of copper under recycle leach conditions

Jan 1, 2023

By J. Jacobs

The three-product cyclone was originally developed in Russia and is now extensively used in China. The cyclone has recently entered the South African coal industry, and with the obvious advantages that this item of process equipment offers our ever-evolving industry it is safe to assume that it will add value to dense medium circuits in South Africa. Some of the possible applications include: ? Producing multiple products using a single dense medium circuit. These can typically be a primary product with calorific value of 27.50 MJ/kg and a secondary (middling) product with a calorific value of 22 MJ/kg ? High-density separation with a low circulating medium density. Anglo Thermal Coal and Exxaro have pioneered the use of these units at Umlalazi and New Clydesdale respectively. Extensive test work has been performed at Umlalazi to determine the efficiency of the unit and to determine how it compares with the conventional DSM (Dutch School of Mines) cyclone. Some people in the coal industry were initially sceptical and expected the performance of the three-product cyclone to be inferior to that of the conventional dense medium cyclone. The results of the test work have, however, shown that the efficiency of the unit is comparable to that of the cyclones currently employed. A valid concern expressed is the control over the cut-point density of the second stage separation, and work is on-going to find the optimal way to control the secondary separation density. Theoretically, the secondary separation density can be manipulated by changing the orifices of the unit, especially the spigot of the secondary stage. This remains to be proven, and a series of tests is currently being planned. Whatever the result of these tests may be, the three-product cyclone definitely has a place in the South African coal processing industry as it offers a low OPEX and CAPEX solution for producing multiple products from a single circuit, as well as the ability to operate at very high separation densities, while making use of low-density circulating medium. Keywords dense medium separation, DSM, three-product cyclone, coal processing.

Nov 1, 2013

By F. G. Hill

The paper reviews the restrictions imposed by the Department of Mines (now the Department of Mineral and Energy Affairs) on the surface use of ground that has been undermined at shallow depths (down to a depth of244m). The reasons for the restrictions are discussed, with special reference to the early records kept by the Department of Mines on subsidence and fracture of the surface. A discussion of the nature of the strata overlying the ore-body, and the effect of undermining, is followed by a detailed account of investigational work, particularly since 1970, on the stability of shallowly undermined ground. The significance of the data collected during the investigations is considered next, with special reference to the social and economic implications. These are so farreaching, that it is proposed that the already flexible approach of the Department of Mineral and Energy Affairs in considering what structures may be built on undermined ground should become even more flexible. To this end, the appointment of a Commission is proposed to collect as much information as possible on the stability of ground undermined at shallow depth, and to revise the current overrestrictive conditions or guide lines that are in use.

Jan 1, 1981

By J. D. Swanepoel, S. Horn, C. J. Badenhorst

Diesel particulate matter (DPM) is the particulate component of diesel exhaust, which includes diesel soot and aerosols. When released into the atmosphere, DPM can take the form of individual particles or chain aggregates, with most in the invisible sub-micrometer range of 100 nanometres. The main particulate fraction of diesel exhaust consists of fine particles and because of their small size, inhaled particles may easily penetrate deep into the lungs. The rough surfaces of these particles make it easy for them to bind with other toxins in the environment, thus increasing the hazards of particle inhalation. DPM is a significant health hazard in underground mining operations, where the use of dieselpowered equipment in confined spaces can lead to high levels of exposure among people working in these environments. Classified as a carcinogen by the International Agency for Research on Cancer (IARC), DPM has been linked to severe health effects, including respiratory and cardiovascular diseases, as well as an increased risk of lung cancer. Effective management of DPM is essential not only for protecting people’s health but also for ensuring regulatory compliance, maintaining operational efficiency, and safeguarding the long-term viability of mining companies.

Mar 5, 2025

By W. Bleloch

In the process described, hydrogen is used to generate high-temperature steam and oxygen in the molten bath. Steel is decarburized to low levels to produce a pearlite-free steel suitable for deep drawing. The process makes use of the favourable thermodynamics in the reactions between steam, carbon, and iron, as well as providing high-temperature oxygen for the decarburizing reaction. The process can easily be incorporated in existing BOF (basic oxygen furnace) plant but can also be contemplated as a greenfield process.

Jan 1, 1987