Search Documents

By R. P. King, L. C. Woollacott

To date developments in the simulation of carbon-in-pulp (CIP) adsorption circuits have focused primarily on the modeling of adsorption. This series of three papers describes a development in a direction that has received less attention, i.e. the need for a detailed description of the movement of carbon and slurry in continuous CIP and carbon-in-leach (CIL) plants. A new simulator has been developed based on the population-balance approach for modeling the movement of carbon and slurry. Existing adsorption and leaching models are evaluated in this paper in order to establish which are appropriate for use in the new simulator. The details of the simulator are given in Part 2 of this series.

Jan 1, 1990

British Mining Fields, by J. E. Metcalf. Published by the Institution of Mining and Metallurgy, London, 1969. Price 50s. (Students, 30s.). A 100 years or so ago Britain's mining industry led the world in the production of coal and base metals. Although she still maintains a sizeable-and, under the circumstances, remarkably progressive-coal mining industry, her production of most other base minerals has long since been dwarfed by mining fields in the Americas Africa, Australia and the U.S.S.R. Nevertheless the story of mining in Britain is of wider interest than the present scale of operations there might suggest, if only because the domestic British mining industry has in terms of finance, technology and manpower been the fons et origo of many highly productive mining fields outside Britain, including the Witwatersrand goldfields. British Mining Fields was published by the Institute of Mining and Metallurgy to give delegates attending the Ninth Commonwealth Mining and Metallurgical Conference a succinct account of mining in Britain. The main emphasis is on underground mining of base minerals-treated regionally-with separate chapters on coal and gypsum. The author strikes an admirable balance between historical aspects, geological origin and environment of ore deposits, mining methods and economic factors, and provides a few key references for those who wish to make deeper studies. This is exactly the sort of booklet one often wishes were available on South African mining.

By S. R. Xie, S. Gong, E. P. Li, S. S. He, Y. J. Sun, S. J. Li

"Based on the complicated geological production conditions and abnormal strata behavior of the fully mechanized caving face No. 102 in the Xinyang Coal Mine, we analyze the breaking and forming process of distinguishing key block structures in close spaced coal seams. This analysis establishes an integrated mechanical model of these distinguishing structures. Furthermore, the horizontal force TAB generated by downward key blocks A and B is quantified, as is the Pressure PG exerted by key block B on caved gangue. Finally, the interaction mechanism is revealed. Analysis of the results using Mathematica reveal the following: 1. Both TAB and PG exhibit approximately inverse relationships to coal pillar width b; 2. TAB exhibits an approximately exponential relationship with mining height M of which the base is greater than 1; 3. PG exhibits an approximately arctangent relationship with mining height M. Combining these results with field observations, we conclude that the area in the vicinity of supports 100#–120# in the upper area of working face No. 102 is the likely zone of abnormal strata behavior. Thus, this area was classified as a key control area. Based on these results, the graded support control technique is proposed. Application of this technique in the field resulted in a reduction in the rate of hydraulic support system malfunction from 47% to 7% in the key control area. In addition, during times of periodic mining pressure, the roof caving height value never exceeded 0.3 m and the maximum spalling depth never exceeded 0.2 m. Overall, the results indicate that this new technique has markedly increased the stability of surrounding support rock material. IntroductionClose-spaced coal seams are widely distributed in China, and mining proceeds from the uppermost to the lowermost seam (Zhang et al., 2008). In the case of coal seams in close proximity, a particular set of risk factors becomes pertinent. These include disturbance of lower seams during the mining of overlying ones and the decrease in mechanical stability of lower coal seams following repeated movement of key blocks in main coal seam roofs. This inevitably results in behaviour such as heavy wall spalling and support damage to fully mechanized caving faces in lower-lying coal seams, which necessitates a significantly increase in the measures to support surrounding rock material (Zhang et al., 2010; Huang et al., 2013; Xie et al., 2013)."

Jan 1, 2016

A 36-year-old A-S-H pump, manufactured to designs dating back to 1936, was recently presented to the Gold Mine Museum by Envirotech. The pump, a B-frame three-piece rubber-lined Hydroseal unit, was supplied by Envirotech's predecessor company, Denver Machinery, and was installed by South Roodepoort Main Reef Areas Limited on 22nd March, 1948. Metals, materials, manufacturing The 37th Annual Conference of the Australasian Institute of Metals will be held in Ballarat (Australia) from 13th to 17th May, 1985. 1985is the Sesquicentennial year of Victoria, and for the first time the historic City of Ballarat has been chosen as the venue for an Australasian Institute of Metals congress. Steel rolling Conferences on steel rolling, sponsored by The Iron and Steel Institute of Japan (ISH), and supported by iron and steel institutes in many countries of the world, have been held since 1980. The first conference was held in Tokyo in 1980, sponsored by The Iron and Steel Institute of Japan.

Jan 1, 1984

By M. Frenzel, K. Bachmann, M. Rudolph, R. Tolosana-Delgado, E. Schach, M. Buchmann, L. Pereiraa, K. G. van den Boogaart, N. Kupka

Geometallurgy - the science of predicting the behaviour of ores along the value chain based on their geological and mineralogical characteristics - has barely moved beyond process minerology studies. These studies typically link process behaviour to the mineralogical and microstructural characteristics of pristine or processed ores in a qualitative or semi-quantitative manner. Eventually, a trial-and-error optimisation of the operation is achieved. However, to deliver on its promise, geometallurgy should progress beyond this current approach to a fully quantitative understanding of process behaviour, including the various uncertainties involved, namely predictive geometallurgy. One of the barriers currently hindering this development is the neglect of most ore characterisation data obtained in geometallurgical studies. This is mostly due to the large extent of this information exceeding the capacity of conventional software. To address this challenge, we developed a data mining platform consisting of an SQL database, an R front-end in-house package, and back-ends to interpret data from several analytical instruments. This platform enables the use of the statistical and data mining power of the R open-source environment for any geometallurgical study. Potential applications range from ore characterisation to process understanding and forecasting, and from geostatistical prediction to operational control and optimisation. The scripting abilities of R allow for the: 1) processing of many streams in loops, thus freeing the user from repeating tedious click-and-drop tasks; 2) computation of virtually any derivate or aggregate quantity from the data; 3) distribution of the work among several processor clusters; and 4) keeping of a log file for the calculations done. This contribution presents the building blocks of this platform, and illustrates with several examples its potential to enable predictive geometallurgy. Keywords: Data mining, entropy, kernel methods, LASSO regression, predictive geometallurgy

Jan 1, 2020

VERSLAG- REPORT No. 1365 STUDIES OF INCIPIENT FUSION IN THE SYSTEM CHROMITE- MgO- Al2O3-SiO2-C 5th January, 1972 Investigator: N. A. Barcza SYNOPSIS A fundamental study was made of twelve chromite ores by use of a thermobalance under atmospheric and reducing conditions. It was found that their thermal behaviour under atmospheric conditions can be related to the mineralogical composition of the chromite spinel and the gangue. The overall mechanism of reduction with solid carbon over the temperature range of 1 200 to 1 500°C was shown to be diffusion of carbon through the reaction product. The effects of additions of fluxes and variations in particle size on the kinetics and mechanism of reduction were determined. It was shown that carbon monoxide does not reduce chromite ore up to temperatures of 1 550 °C, and it can therefore be eliminated as the diffusing reducing species. However, the reaction product of reduction, namely a mixed carbide of iron and chromium, was shown to be an effective reducing agent for chromitc ore, while also facilitating the transport of carbon. VERSLAG - REPORT No. 1380 AN ELECTROCHEMICAL MODEL FOR THE LEACHING OF URANIUM DIOXIDE 10th January, 1972 Investigators: C. R. S. Needes, M. J. Nicol SYNOPSIS A correlation between the rate of leaching of UO2 and the electrochemical properties of the oxidant concerned has been derived. This correlation is found to be borne out by experimental results. Certain effects observed in UO2 leaching and hitherto unexplained have been clarified in terms of an electrochemical mechanism. Experiments have shown that the mixed potential of a UO2 electrode gives a measure of the rate of dissolution of UO2. Its significance to commercial practice is discussed. CONCLUSIONS (I) The dissolution of UO2 in the presence of a number of oxidants can be explained in terms of an electrochemical mechanism. (2) The mixed potential of the UO2 electrode is a measure of the rate of UO2 leaching. This principle could be used in the control of industrial leaching operations. (3) A simple treatment has provided a mathematical basis for a fundamental correlation between the rate of U02 dissolution and the chemical properties of the oxidants concerned. This relation has been found to agree well with experimental results. (4) A number of phenomena occurring during the leaching of UO2, hitherto not explained in a satisfactory manner, have now been clarified in terms of an electrochemical mechanism.

The following is available free of charge from the Bismuth Institute, rue Brederode 9, B-I000 Brussels, Belgium: The chemical analysis of bismuth. Automatic methods of guiding welding heads along butt joints. Investigations into lamellar tearing. A technical survey of seam tracking methods in welding. Review - Seawater corrosion handbook, by M. Schumacher (editor). New Jersey, Noyes Data Corporation, 1979. New journal February 1979 marked the appearance of a new monthly journal, Lloyd's Shipping Economist. New edition Gasification of coal, a basic study of existing processes and new developments, by H. D. Schilling, B. Bonn, and U. Krauss (edited by W. Peters). Essen (West Germany), Verlag Gltickauf GMBH, 1979. 2nd revised edition. 336 pp. 68DM (approximately R32). In German. South African technikons The six autonomous colleges for advanced technical education in South Africa were established in terms of the Advanced Technical Education Act (Act 40 of 1967). However, since the inception of these colleges, it has become clear that members of the public find the name difficult to use and to remember. Consequently, these colleges, which play such an important role in the community, were not always correctly identified. Die forging The 9th International Conference on Die Forging will be held from Monday, 4th to Saturday 9th May, 1981, in Diisseldorf, Federal Republic of Germany. It is being organized jointly by the Forging Committee of the Verein Deutscher Eisenhiittenleute and the Vereinigung Deutscher Freiformschmieden. High-temperature alloys An International Conference on the Behaviour of High Temperature Alloys in Aggressive Environments will be held in Petten (North-Holland) from 15th to 18th October, 1979. Strategic minerals The National symposium on the availability of strategic minerals, which is being organized by the Institution of Mining and Metallurgy in collaboration with the Fellowship of Engineering, will be held at the London Press Centre, New Street Square, London EC4, on 20th and 21st November, 1979. The symposium has as its main objective consideration of those minerals that may pose problems of availability in the United Kingdom. Underwater mining The 10th Annual Underwater Mining Institute is scheduled for 1st to 3rd October, 1979, at Galveston, Texas. The Institute will be cosponsored by the Sea Grant College Programs of the University of Wisconsin and Texas A & M University and by the Marine Science Institute of the University of Texas it is being held in co-operation with the Association for Marine Mining. Die Suid-Afrikaanse Instituut Vir Mynbou En Metallurgie - Inligting Oor Lidmaatskap.

Jan 1, 1979

By M. J. H. Tonkins, C. C. Crosson, G. Paterson

The development of drilling and blasting practice at Palabora Mining Company Limited by c. C. CROSSON, Pr. Eng., A.C.S.M. (Hons), BASe. (Min. Eng.) Toronto, M.!.M.M. (Member), M. J. H. TONKING, Pr. Eng., A.C.S.M., BASe. (Min. Eng.) Toronto, M.I.M.M. (Member), and G. PATERSON, B.Se. (Min. Eng.) Glasgow, M.!.M.M. (Visitor) Open-pit drilling and blasting practice at the Palabora Mining Company Limited is described, with particular reference to the development of aluminized slurry explosives. Rotary drilling of primary drill holes, drilling patterns, and blasting techniques for use with slurry explosives are described.

Jan 2, 1976

By J. P. McDonald, P. L. Mattison, J. M. W. Mackenzie

A variety of processing problems in the hydrometallurgical extraction of uranium in the U.S.A. are contrasted with those in South Africa. In U.S. plants, for example, problems are often encountered in the separation of vanadium, molybdenum, and uranium, and in the contamination of the circuit with organic acids. South African plants often experience problems with dissolved silica in the feed, clarification of feeds, and problems associated with synthetic polyelectrolytes. Individual situations are examined, along with the analytical techniques that assist in solving specific problems. Successful approaches that have been applied to mechanical and chemical problems in' uranium solvent-extraction plants are discussed.

Jan 1, 1981

By R. S. Sanders, J. Schaan

Syncrude Canada Ltd. produces synthetic crude oil from Canada?s vast oil sand reserves by mining the oil sand, then separating and upgrading the ultra-viscous crude oil, or bitumen (~ 106mPa s @ 10ºC). At Syncrude?s Aurora Mine, about 16 000 tonnes oil sand per hour are mined and then transported 5 km by slurry pipeline to the extraction plant. The waste tailings stream is then transported about10 km by pipeline to a settling/sand storage basin. Oil sand slurries are reasonably concentrated (> 35%solids by volume), typically have a sand particle diameter between 0.18 and 0.3 mm, and are transported at reasonably high velocities (3 to 5.5 m/s). As one would expect, pipeline wear is a significant problem in this industry, in terms of both unplanned production outages and maintenance costs. In order to develop strategies to extend pipe life and to focus more on condition-based maintenance scheduling (as opposed to preventative maintenance), Syncrude has implemented an ongoing pipe wear measurement programme. Regular measurements of pipe wall thickness are obtained at various circumferential positions at a number of axial locations along each pipeline, using an ultrasonic scanning technique. In this paper, we show how wear rates vary as a function of axial location and circumferential position for oil sand hydro transport and coarse particle tailings pipelines. The specific positions at which peak wear rates occur are explained by considering the characteristics of the coarse particle slurry flows to which the pipelines are exposed.

Jan 1, 2007

By G. H. Morton

The tenth international symposium on the application of computer methods in the mineral industry (APCOM) was held in Johannesburg in April; the first time it had taken place outside North America. In the technical sessions fifty-seven papers were presented, providing a review of current work and including some important original contributions. These papers and a full account of the discussion at the symposium will soon be published in a single volume. The Technical Programme The first session of the symposium included an opening address given by Mr J. W. Shilling, President of the Chamber of Mines of South Africa, and a keynote address by Mr K. F. Lane of the Rio Tinto Corporation Limited. Mr Shilling spoke about the history of the South African mining industry and about some of the work of the Chamber of Mines. He stressed the importance of the symposium in familiarising those in mining with computer applications, and expressed his hope that it would stimulate and inspire scientists and engineers in the effort to develop safer and more economic methods of mining. Mr Lane, talking about economic and financial modelling, gave a fascinating account of the experience of RTZ over the last twelve years. In a very honest appraisal of the substantial progress that had been made, he confessed some disappointment not only in the cost and

By J. W. van der Merwe, C Strydom, D. C. Odendaal, M. I. Sampson

Keywords: Sphalerite, Bio leaching, Chemical leaching Sphalerite concentrates were prepared from tailings dam samples obtained from Rosh Pinah Mine in Namibia. The samples were subjected to froth flotation and concentrates containing between 7% and 14% Zn were prepared. Leaching of these froth flotation concentrates were studied in ferric chloride solutions at different Fe3+ concentrations for different times at different temperatures with the influence of other species on the kinetics in mind. Complementary to this research, GeoBiotics, LLC and Exxaro Resources have developed proprietary bioleaching technology for the oxidation of base metals concentrates using GEOCOAT bio heap leaching technology in a sulphate medium. The ferric chloride laboratory work was performed in a fluidising leach reactor. The studied material was obtained from flotation concentrate produced during an investigation into the recoverability of a tailings pile at Rosh Pinah mine in Namibia. The optimum conditions for the laboratory investigation were found to be a Fe3+ concentration of 0.3 mol/dm3 at 80°C. A control was performed by using synthetic zinc sulphide. GEOCOAT evaluation tests are performed for the purpose of evaluating the bioleaching of ore and flotation concentrates by means of mesophilic bacteria, Column tests were carried out on the flotation scavenger concentrate from Rosh Pinah to assess the application of the GEOCOAT® process for the oxidation of a low grade zinc concentrate. In this study an attempt was made to demonstrate the relationship between the Kinetic models and the experimental data by plotting the fraction of Zinc leached against time and applying the different equations to the data. The kinetic models were applied to the data obtained from both the test regimes. Habashi (1999) proposed that if a process is controlled by a chemical reaction at the interface (phase boundary controlled reaction), the following equation applies. kCt =1 ? (1-R) 1/3 Alternatively a process is controlled by diffusion through the product layer the following equation applies: [kt = 1 23- X (1 ? X) 2/3] As the anodic dissolution reaction progresses, reaction product forms either a more or less dense reaction product layer on surface As this product layer forms, a diffusion problem develops governed by the nature of the product layer. The conclusion from the study was that the kinetics is very dependent on the type of ore processed relating to the mineral composition of the ore body.

Jan 1, 2007

By W. J. Vlasblom, A. M. Talmon, A. J. Nobel

In initial laboratory tests with a travelling submerged jet on artificially prepared clay it was found that the cavity depth is dependent on the stagnation pressure of the jet and the undrained shear strength of the clay. In addition, it has been observed that the increase in cavity depth with jet pressure is stronger at higher jet pressures. It is assumed that this can be explained by cavitation of the jet at higher jet pressures. At cavitation a cone of bubbles is formed around the jet, which reduces the exchange of momentum between the jet and the surrounding water. This results in a higher jet velocity and a higher stagnation pressure at a specified distance from the nozzle exit. In literature, no relation between the jet pressure of a free submerged cavitating jet and stagnation pressures was found. Additional tests were carried out to determine this relationship. Because practical dredging occurs at relatively large water depths, these tests were performed in a pressure vessel at different pressure levels. It is concluded that the efficiency of a jet (defined as the stagnation pressure at a certain distance divided by the jet pressure), for stand-off-distances smaller than 45 times the nozzle diameter, increases significantly by cavitation in comparison to the non-cavitating situation. However, the jet pressure required for a fully developed cavitation cone increases strongly with water depth. At dredging depths of 20 m and more, the necessary jet pressures are higher than normally applied in dredging practice. Thus in spite of the importance of cavitation in laboratory tests at atmospheric pressure, in normal dredging practice cavitation is of less importance.

Jan 1, 2007

The Centenary Luncheon for Past Presidents was held on Thursday, 24 March, 1994 at The President's Room at Gold Reef City, Johannesburg at 12:30. Herewith the proceedings that followed. Dr H. Scot-Russell It is with great pleasure that my fellow Office Bearers and I welcome you, our Past Presidents, to this luncheon to mark the centenary of the SAIMM. Today one hundred years ago, a group of professionals met and agreed to draw up the constitution and by-laws of a society later to be called an Institute. The Presidents of the Institute, of course, become its Past Presidents and help to guide its progress. A number of our sister institutes cannot wait for their Past Presidents to move of their councils, and cannot understand how we can give such free reign to ours! We believe it one of our strengths. The successful cooperation between our Past Presidents and ourselves is due to the personalities of these men. They attend meetings not to ensure that the status quo is maintained, but allow the current Office Bearers freedom to lead the Institute as they think fit. But they are always present to give sound advice, a helping hand, and support to the Institute in every way.

Jan 1, 1994

By P. G. Van Der Walt

This paper deals with the reticulation of deslimed tailings from surface to the stope face underground. Reference is made to the experience gained at the pilot plants operating on four of the gold mines administered by Gold Fields of South Africa, as well as at the full-scale system at East Driefontein which was commissioned recently. Mine-wide backfill systems are currently being installed on five other mines administered by Gold Fields. These six full-scale systems are capable of handling more than 270 000 tons of backfill solids per month. The type of reticulation system chosen, the selection of flowrates and the composition of the slurry, as well as the selection of the appropriate pipes and ancillary equipment are discussed. Both theoretical and practical aspects are taken into consideration. Other aspects covered include the design of underground storage dams and communication systems.

Jan 1, 1988

Professor Miklos Salamon, Research Adviser to the Chamber of Mines of South Africa, has won the Rock Mechanics Award for 1983 of the American Institute of Mining, Metallurgical and Petroleum Engineers 'for applications of analysis to many varied practical mine design problems’. Mintek reports Report M119 A versatile computer programme for data capture in multi-element analysis by a sequential X-ray spectrometer. Report M120 South African costs of equipment for the metallurgical industry (1983). Report M125 Commissioning of an automated microphotometer used in spark-source mass spectrometry.

Jan 1, 1984

By A. P. W. Briggs

Difficulties with the screening of large volumes of pulp to remove plus 600 /km material before the adsorption circuit and to retain plus 20-mesh carbon in the adsorption contactors have largely been solved, with the result that the plant can now handle its design throughput. The elution and electrowinning processes have been modified to simplify the circuit, but the regeneration of carbon remains unsatisfactory. The production of fine carbon in the plant can lead to increased gold losses, and this carbon must be collected and treated. Collection methods for fine carbon and some indications of the quantity of the carbon and its gold values are given.

Jan 1, 1983

By Arvi Parbo

I would like to use the occasion to reflect on how the world environment for the minerals industry is undergoing substantial change, and how this change may affect the industry. I have given my talk the title 'The Quest For Competitive Edge', because the net effect of the changes taking place is that competition is increasing. To set the scene, let us look back at the situation which has existed in our industry in the past.

Jan 1, 1993

By G. T. van Rooyen

Materials for Winding Plant Components By Prof. G. T. van Rooyen (ScD) (MIT). Materials for critical applications such as winding plant components are reviewed in terms of the basic requirements which have to be complied with. It is shown that tensile testing alone is not sufficient and that impact testing also is necessary if the incidence of brittle fracture is to be avoided. As a criterion it is suggested that the brittle transition temperature (B.T.T.) determined by impact testing should in all cases be well below the lowest anticipated service temperature. A number of steels were evaluated by impact testing and it is shown that a small ferrite grain size, obtained either by chemical means such as by the use of appropriate alloying elements in the steel or by means of a quenching heat treatment, is effective in attaining a Iow B.T.T. The speed of strain aging as well as the influence of strain aging on the B.T.T. was also evaluated. On the basis of the results obtained it is recommended that steels for critical applications must conform to an appropriate grade and class of steel according to BS 4360 specification. It is further recommended that such steels be exempted from the customary six-monthly heat treatment prescribed by the Mines and Work Act, Regulation 16,18.

A method is proposed for the evaluation of the influence of grout prestressing systems on the support resistance offered by timber packs. It is shown that, in order not to reduce the load-carrying capacity of timber packs, grout prestressing systems need to be at least as stiff as a single timber rise. The method was used to establish strength specifications for the grout prestressing systems to be used under non-seismic and seismic conditions. For non-seismic requirements, the 24-hour grout strength needs to be at least 1,7 MPa, and the 7-day grout strength 4,9 MPa. The investigation showed that the proposed strength specification is realistic in the light of current grout-strength capabilities. For seismic requirements, the grout strength needs to be at least 4 MPa and 8 MPa to prevent extensive damage to the grout during seismic events with a peak velocity of 1m/s 3 m/s respectively.

Jan 1, 1996