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Reviewer: P.R. Janisch The progress of mining and metallurgy in Australia and their contribution to that nation's economy closely parallel those of South Africa. Australia's was the second of the three great gold rushes of the nineteenth century. It was centred on Bendigo and Ballarat in Victoria, and occurred in the 1850's, a few years after California's forty-niners. The California goldfield also gave birth to the now common term for a tabular gold bearing deposit-a 'reef'. Amongst the fortune-seekers were sailors who had jumped ship on hearing of the riches to be found on land. When the gold ran out, and with it the money, the sailors found themselves stuck on a reef'. But others, more canny, had accumulated the means to move on, and some came to the Transvaal on the news of the Barberton discoveries. One of them was George Harrison.

Jan 1, 1993

By Wm. Bleloch

SYNOPSIS The feasibility of rejection of nitrogen from stack gas by recycling of top-gas with cold-blast 95 to 98 per cent oxygen is assessed. It is concluded that nitrogen could be removed to a level below 3 per cent of the stack-gas using recycled cleaned cold top-gas and 95 to 98 per cent oxygen produced by a single-column air separation plant with liquid-air reflux instead of liquid nigroten reflux. The partial pressure of carbon monoxide in the stack-gas could be doubled without top pressure and the deposition of carbon and reduction of iron oxides by the stack gas could be markedly increased. It is concluded that rate of stock descent could be doubled compared with present-day practice and an iron make of 4400 kg/m 2 of hearth area/hour may be attainable with a working volume of 129 m2/m hearth diameter by this method. Oxygen consumption is estimated at possibly 280 m2 (0.4 t)/t iron made and carbon consumption at possibly 280 kg/t iron. Power consumption for oxygen including auxiliaries is estimated at 304 kWH/t 100 per cent oxygen as 95 to 98 per cent gas. The air separation cycle due to Schuftan is discussed in some detail, and the components of a 1 600 metric ton/day separation plant are briefly discussed. The paper is a theoretical essay.

By J. Svoboda, W. J. C. Venter, R. N. Guest

SYNOPSIS Wet high-intensity magnetic separation was examined as a method for the recovery of copper and lead from Tsumeb flotation tailings. Bench-scale and pilot-plant tests were conducted and, despite the very low magnetic susceptibilities of all the complex copper and lead minerals, copper and lead recoveries of over 60 per cent and almost 50 per cent respectively were obtained at a combined copper and lead grade of up to 13,5 per cent. The recoveries were found to be practically independent of magnetic induction in the range 0,5 to 2,2 T, and the grade of the magnetic concentrate decreased with increasing magnetic induction. The grade of the magnetic concen¬trate improved when the flowrate of the slurry was increased, and desliming was found to have a profound effect on the. metallurgical process. Particles smaller than 10 µm were not recovered, and their presence in inefficiently deslimed samples impaired the overall performance of the magnetic separation

Jan 1, 1988

NOTICE The Institute has received requests for copies of Uranium in South Africa', Vols. 1 and 2, but is unable to supply, as all copies have been sold out. If any members have copies they wish to dispose of it would be appreciated if they would contact the Secretary, P.O. Box 1183, Johannesburg. Telephone 834-1271.

By A. Mehmet

The feasibility of employing a multi-stage column for the recovery of gold from cyanided pulps using extruded carbon was investigated on a pilot-plant scale. It was anticipated that the column contactor would have certain advantages over conventional carbon-in-pulp plants. The feed pulp was screened to remove particles larger than 200 µm and was diluted to a solids concentration of about 23 per cent. The column was operated continuously for 24 days at a pulp flowrate of about 60 l/min and a carbon flowrate of 44 litres per day. The average gold concentrations in the barren pulp 12 hours and 24 hours after the carbon transfer were 0,012 and 0,031 mg/l respectively. The average gold concentration in the solution phase in the feed was about 2,0 mg/L. The average gold Loading on the carbon was 6290 g/t. Calcium carbonate was removed from the loaded carbon by treatment with 0,5 bed volumes of 2,8 per cent hydrochloric acid solution at ambient temperature. The calcium concentration was reduced from about 17 000 to about 500 g/t The carbon was eluted by the Zadra procedure at atmospheric pressure. The results of the elution were highly satisfactory, the gold concentration being reduced from about 6000 to about 20 g/t in 48 hours. The eluted carbon was regenerated in a Rintoul kiln at about 700°C. The activity of the regenerated carbon was found to be at least as high as that of fresh carbon.

Jan 1, 1992

By J. T. M. Amphlett, C. A. Sharrad, M. D. Ogden, R. I. Foster

"A renewed interest in nuclear power around the world in order to reduce greenhouse gas emissions is going to increase demand for uranium as fuel. This will result in more uranium being mined, which will in turn increase associated environmental pressures, such as fresh water use. A move to lower quality waters containing impurities such as chloride would help alleviate these pressures. In this work, we determined the uptake characteristics of weakly basic anion exchange resin Ps-EDA towards uranium from saline solutions in a dynamic flow column. Breakthrough curves were produced, with suppression of uptake being observed for chloride concentrations above 5 g L-1. Calculated resin saturation capacities at zero and 5 g L-1 chloride are comparable with literature values for strong-base anion exchange resins, and exceed those published for weak-base resins up to 20 g L-1 chloride. Data has been fitted to multiple breakthrough models, with the modified dose-response model most effectively predicting uranium recovery. The results show that the ethylenediamine functionality could be suitable for use in future uranium processing flow sheets where a high-saline lixiviant is used. IntroductionIon exchange (IX) is a key technology in the uranium mining industry and is well established for the extraction of uranium from both acidic and alkaline leach liquors (Edwards and Oliver, 2000). It was first employed in 1952 at the West Rand mine in South Africa (Ford, 1993; Taylor, 2016). H2SO4 and Na2CO3 are the most commonly employed lixiviants used to solubilize uranium in acidic and alkaline leach conditions respectively. The chemistry of these systems causes uranium to form anionic sulphate or carbonate complexes, which can be taken advantage of by anion exchange resins.Another major technology for the extraction and purification of uranium from leach liquors is solvent extraction (SX). This technique involves the extraction of uranium from the aqueous phase into an immiscible organic layer. Although this is a commonly used method, there are major drawbacks to it, including the use of large volumes of flammable solvents, solvent loss, phase disengagement, third phase formation, and the production of problematic degradation products (Veliscek-Carolan, 2016). These problems can be circumvented through the use of IX resins."

Dec 1, 2018

Rock mass classification systems are extensively used in rock engineering design work, and mine design is no exception. Among the systems most widely used for mining-related design work are the NGI 0-system (Barton et al., 1974), the RMR system (Bieniawski, 1976), the MRMR system (Laubscher and Taylor, 1976) and, more recently, the GSI system (Hoek et al., 1998). Classifying the rock mass is widely seen as being the fieldwork required to characterize the rock mass and enable the application of empirical design methods associated with the different classification systems. This paper argues that it is fundamentally important to recognize the distinction between rock mass characterization and rock mass classification. These two processes should, in most cases, be separated from each other. Rock mass characterization should be used to determine the intrinsic properties of the rock mass independently of the application; i.e. independent from the infrastructure to be designed, the size, shape, and orientation of the excavation(s) or pillar(s), etc. Rock mass characterization should also be compatible with most classification systems and empirical design methods to be used. Rock mass characterization is the background fieldwork required to perform rock mass classification and/or engineering design work. Rock mass classification is the subsequent step to the characterization, and an integral part of the design process. Parameters that vary according to the design, such as the relative orientation of geological structures compared to the opening or the mine-induced stresses, should be calculated as part of the rock mass classification and design process, rather than during the rock mass characterization process. The failure to distinguish between rock mass characterization and rock mass classification can lead to major design errors and poor results.

Jan 1, 2012

Edward J. Stephenson. Extractive metallurgy. Recent advances. Park Ridge (New Jersey), Noyes Data Corporation. James L. McCall and P. M. French (eds.). Interpretive techniques for microstructural analysis. 1977. Institution of Mining and Metallurgy. Prospecting in areas of glaciated terrain. London, the Institution, 1977. £16 ($D.S. 30). NIM reports Report no. 1928 A liquid-nitrogen monitor for lithium-drifted germanium detectors. (21st Nov., 1977). Report no. 1931 The equilibrium between the slag and the metal in the production of low-carbon ferromanganese. (14th Nov., 1977). Report no. 1934 The spectrometric analysis of chromium-bearing materials with particular reference to ferrochromium slags and chromite ores. (30th Nov., 1977). Report no. 1935 The construction and testing of a small mixer-settler for use in the laboratory. (30th Nov., 1977). Report no. 1933 The determination of trace elements by thin-film X-rayfluorescence spectrometry, and its application to zirconium. (30th Nov. 1977). Report no. 1942 The accuracy of assays for platinum -group metals and gold. (30th Nov., 1977). Courses on geostatistics In view of the continuing demand, the University of Leeds will offer two further courses on geostatistics in 1978, each covering ten working days (3rd to 14th April, and 3rd to 14th July).

Jan 1, 1978

By F. T. Cawood

This paper reviews the Mineral and Petroleum Resources Royalty Bill of 2006, identifies potential areas that require further consideration by the National Treasury and, where appropriate, offers alternatives. At its basic level a royalty regime consists of two elements: the base and the rate that must be applied to the base. Deciding on an acceptable royalty rate is a complex matter and can be done only after extensive analysis of all variables affecting the competitiveness of the regime. The proposed royalty rates are in the range of zero to five per cent and are based on sales revenue. It is argued that future investment patterns are more likely to be influenced by market cycles and commodity prices than policy events. Inevitably the current boom in the minerals sector will come to an end and the success of the proposed regime will be known only when profit margins are under pressure. Policy makers must therefore have the long run in mind when developing policies that affect the ability of industry to do business, without the need to renegotiate each time there is a change in the market. A long-run policy must be sufficiently flexible to allow for consistently fair sharing ratios and splitting of revenues between government and industry. Although broadly in line with international practice, the current version cannot be regarded as internationally competitive and efficient. In order for the royalty bill to become internationally competitive, promote beneficiation of mineral production and adequately compensate the State for the loss of a national resource, the National Treasury should heed the following main recommendations in this review: 1. Abandon the notion that each mineral product must have its own royalty rate; 2. Introduce an NSR type royalty that allows for value-addition costs to be deducted from the base; and 3. Provide for automatic relief through the use of a sliding-scale mechanism based on ability to pay, e.g. the X-Factor used in the gold mining tax formula.

Jan 1, 2007

By S. Moodley

In the chloride process for TiO2 pigment production, various titania feedstocks (i.e. rutile, synthetic rutile, slag, and upgraded titania slag (UGS)) are chlorinated in a fluidized bed reactor with petroleum coke at temperatures between 1000°C and 1100ºC to yield gaseous metal chlorides. Although feedstock preference is largely based on TiO2 content, feedstock physical properties (i.e. density, sphericity, size distribution, and porosity) differ; these differences will affect fluidization behaviour and can inadvertently affect conversion efficiency. For example, a high carryover from the reactor reduces particle residence time and decreases conversion rates. Owing to dwindling rutile reserves in the world, most chloride producers are forced to feed blends of feedstocks to their chlorinators; and so it becomes important to understand whether blends have an effect on the hydrodynamic properties of the bed. This paper describes the physical characterization of different feeds and the determination of the elutriation constants for slag, rutile, synthetic rutile, and a blend (i.e. 50 wt% rutile, 50 wt% slag).A common feature of the tests was that particles finer than 75 µm tended more than any other size to be elutriated. The tested rutile, classified as a Geldart Group B material, had the lowest carryover, whereas the slags had the highest. Interestingly, the elutriation constant ([ki]) of the blend is lower than those of either of its individual components.

Jan 1, 2012

By B. Yu, M-H. Cao, C. Zhou, X-Z. Zhang

The transient infiltration and lubrication behaviour of slag during continuous casting of steel is important for billet quality. A two-dimensional coupled mathematical mould model was developed to investigate these phenomena. The accuracy of the model was verified by comparing the calculated slag consumption with measurements by the plant. The results show that the liquid slag is consumed from the middle and late period of positive strip time to the next early period of positive strip time, including the entire negative strip time. The maximum downward infiltration velocity and positive pressure in the slag channel is at the middle of the negative strip time. Increasing the positive pressure of the slag channel is conducive to lubrication. The shear stresses acting on the shell surface and at the mould side were determined by the lubrication slag consumption and total slag consumption, respectively, and gradually decreased with increasing slag consumption. The negative strip time was lengthened to increase the slag consumption and prolong the time near the maximum downward shear stress, so as to be conducive to the demould.

Apr 16, 2024

By J. L. Havenga

South Africa produces about 400 Kt zircon (ZrSiO4) per annum. This represents about 30 percent of the global demand. However, very little is beneficiated locally and more than 95 percent is exported with little or no value addition. Zircon is a very inert material and needs to undergo high-temperature alkaline melting processes to produce valuable zirconium products. The conversion of zircon to plasma-dissociated zircon (PDZ) produces a chemically reactive species (ZrO2.SiO2) which consist of finely divided submicron monoclinic ZrO2 crystals dispersed in a SiO2 matrix. In this paper, an in-flight, non-transferred arc pilot plasma plant with a capacity of 100 kg/h and which consists of three 150 kW DC plasma torches, is described. The optimization of the plant, which includes the use of different zircon concentrates, the influence of particle size, feed rates, plasma gas, and energy utilization, is discussed.

Jan 1, 2012

By J. L. Havenga

South Africa produces about 400 Kt zircon (ZrSiO4) per annum. This represents about 30 percent of the global demand. However, very little is beneficiated locally and more than 95 percent is exported with little or no value addition. Zircon is a very inert material and needs to undergo high-temperature alkaline melting processes to produce valuable zirconium products. The conversion of zircon to plasma-dissociated zircon (PDZ) produces a chemically reactive species (ZrO2.SiO2) which consist of finely divided submicron monoclinic ZrO2 crystals dispersed in a SiO2 matrix. In this paper, an in-flight, non-transferred arc pilot plasma plant with a capacity of 100 kg/h and which consists of three 150 kW DC plasma torches, is described. The optimization of the plant, which includes the use of different zircon concentrates, the influence of particle size, feed rates, plasma gas, and energy utilization, is discussed.

Jan 1, 2012

By A. Navarra, A. Quelopana

The mine production scheduling problem (MPSP) has been studied since the 1960s, and remains an active area of computational research. In extending the concepts of the MPSP, the automated mine may now be regarded as a hierarchical intelligent agent in which the bottom layer consists of distributed robotic equipment, while strategic functionality occupies the higher layers. Here we present a disambiguation of artificial intelligence, machine learning, computational optimization, and automation within the mining context. Specifically, the Q-learning algorithm has been adapted to generate the initial solutions for a high-performing strategic mine planning algorithm, originally developed by Lamghari, Dimitrakopoulos and Ferland, based on the variable neighbourhood descent (VND) metaheuristic. The hierarchical intelligent agent is presented as an integrative conceptual platform, defining the interaction between our new Q-learning adaptation and Lamghari’s VND, and potentially other hierarchically controlled components of an artificially intelligent mine, having various degrees of automation. Sample computations involving Q-learning and VND are presented.

Dec 1, 2021

By k. Lebecki, S. Trzcionka

The prototype and test results of the instrument for quick determination of incombustible content in deposited dust as a protection against coal dust explosion propagation are presented. Presently existing methods do not permit to obtain quick information about incombustible content, needed for the proper protection of workings. As the operating principle for the e instrument the dependence of reflection of infrared radiation intensity on incombustible content in the sample is chosen. The construction is based on the modern electronics. The measurement will be done at the sampling site. The range of the instrument is 0-100% of incombustible, direct reading, autonomous supply, weight no more than 0.5 kg, and is intrinsically safe according to EN Standards. During the Conference the instrument will be commercialized.

Jan 1, 2003

By E. Minnaar, P. J. Cilliers, M. Bellino, L. M. Roux, R. Dye

The classic technique to remove impurities in a cobalt stream is selective precipitation. This is usually followed by re-leaching to produce an advanced electrolyte for cobalt electrowinning. Although this technique ensures an adequate cobalt concentration in the electrowinning circuit, some of the consequences include unwanted losses through the numerous selective precipitation steps resulting in lower recoveries. One plant that currently utilizes selective precipitation is the Luilu Metallurgical Plant (Luilu) in the Democratic Republic of the Congo. This paper evaluates the benefits of using solvent extraction technology as a purification step in the Luilu Process with the aim of further increasing the overall cobalt recovery and to ensure that a suitable cobalt concentration in the advanced electrolyte is achieved. The implementation of a solvent extraction-electrowinning process is found to be beneficial in terms of achieving improved recoveries and cobalt cathode quality, however there are many other factors that impact the success of converting from the classic precipitation process used at Luilu.

Jan 1, 2007

By C. Kliem

Geological, tectonic, geochemical and geophysical data were utilized for the mineral resource assessment of the Biga Peninsula in NW Turkey. During the deductive phase of the project multivariate statistical methods were applied to accentuate characteristic parameters which sufficiently describe the different types of Pb - Zn mineralization. The parameters most likely to be indicative of mineral occurrences were determined. In the following prognostic phase these parameters were further statistically treated to determine favourability indexes for the occurrence of a deposit within each cell of the training area. Preliminary results of probabilistic, univariate and multivariate methods are presented.

Jan 1, 1987

By R. G. B. Pickering, H. H. Haase

CONTRIBUTION BY D. O'CONNOR Mechanical extraction of rock has been a goal sought after for some decades in the South African gold-mining industry. There are factors distinct from the mode of mechanical extraction that may have considerable influence on its prospects for extensive adoption; the rockburst factor is one of these. REPLY BY H.H. HAASE AND R.G.B PICKERING We agree with Professor O'Connor that, in conventional gold-mining operations, a disproportionate number of seismic events occur in the period immediately following a blast; rockburst activity follows the same pattern, and it has been calculated that, if the rockburst peak were spread evenly across the day, the rockburst exposure of stope workers would nearly double.

Jan 1, 1992

New Journals The following three journals may be of interest to readers: Fuel Processing Technology, Process Economics International, Speculations in Science and Technology, MM reports Report no. 2016 Analysis of the NIMROC reference samples for majorelements. Report no. 2018 Supergene aUeration of sulphide ores. II. The effect on the floatability of chalcopyrite, galena, and sphalerite. Report no. 2013 List of unrestricted NI M publications issued from 1966 to 1979. Report no. 2014 The determination by spark-source mass spectrometry, of chlorine and phosphorus in high-purity tungstic oxide. Report no. 2017 Vanadium-bearing titaniferous iron ores from the Rooiwater, Usushwana, Mambula, Kaffirskraal, and Trompsburg Igneous Complexes. Report no. 2022 The determination of thallium and indium in sulphide concentrates. Report no. 2023 Atomic-absorption spectrophotometry with hydride generation: an improved technique. Proceedings Proceedings of the Eleventh Commonwealth Mining and Metallurgical Congress, Hong Kong, 1978. London, Institution of Mining and Metallurgy, 1979. 800 pp. 35,00 or $U.S.77,00.

Jan 1, 1979

By K. G. Lomberg

The integration of various highly sophisticated IT applications has been implemented at Bafokeng Rasimone Platinum Mine, a new platinum mine in the Anglo Platinum Group. This system is required to assist with compiling the necessary geological and grade information together with safety, environmental, ventilation, rock engineering and logistical constraints, to allow the design of the appropriate mining layout, to schedule this design, provide the necessary output for technical review and costing as well as budgeting to allow medium- and long-term business planning. In addition the production management and short-term planning needs must be met. This includes the plotting of all underground and surface infrastructure and excavations, giving the necessary mining and best cut instructions, daily production management, ore reserve and grade management as well as assisting with budgetary management. In addition all safety, health, environment and risk assessment requirements and legal requirements have to be met. The system at Bafokeng Rasimone Platinum Mine has met these criteria. Keywords: Platinum, Bushveld Complex, Mine Planning, Production Management

Jan 1, 2003