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By W. P. Channon, J. B. See

The reduction of fluxed and non-fluxed manganese, ores by ferromanganese silicide by W. P. CHANNON, B.Se. (Eng.), M.Sce. (Eng.) Wits. (Visitor) and J. B. SEE, B.Sce. Hons., Ph.D. (New South Wales), M.I.M., M.I.M.M. (Member) In South Africa, medium-carbonferromanganese is produced by the silicothermic reduction of slags containing MnO. Because of its importance in the production of refined ferromanganese, a study was made of the reaction between a premelted South African Mamatwan manganese ore and various ferromanganese silicide reducing alloys, with and without fluxing agents. Because the reaction is highly exothermic, temperature appeared to have little effect on the rates of manganese transfer to the metal and silicon transfer to the slag, and an apparent equilibrium was rapidly approached. Limits were determined for the favourable effects of fluxing additions, and manganese recoveries were found to decline as the ratio of CaO to MgO decreased as a result of the addition of basic flux. The recovery of manganese passed through a maximum, and subsequently decreased for variations in the ratio of alloy to ore. The results obtained, when used in conjunction with other physicochemical data related to this slag-metal system, suggest optimum slag compositions for the efficient manufacture of medium-carbon ferromanganese from Mamatwan ore.

Jan 3, 1977

1. Books from Elsevier The folowing are available from Elsevier Applied Science, Crown House, Linton Road, Barking, Essex IGl 8JO, OK. . Driling wastes, edited by F.R. Engelhardt, J.P. Ray, and A.H. Gilam. 1989. 872 pp. £95. Geothermal resources, by R. Bowen. 2nd ed. 1989. 468 pp. £60. The fate and efects of oil in freshwater, edited by J. Green and M.W. Tret. 1989. 340 pp. £42. Mining and the freshwater environment, by Martyn Kely (with contributions by W.J. Alison, A.R. Garman, and C.J. Symon). 1988. 228 pp. £32. 2. Books produced by Metal Buletin The folowing are available from Metal Buletin PLC, Park House, Park Terace, Worcester Park, Surey KT47HY, England. Prices and data 1990. £41 (airmail). Foundry directory and register of forges 1989-1990. £52 (airmail). 2. Canadian Publications The folowing two publications are available from the Canadian Government Publishing Centre, Supply and Services Canada, Otawa, Canada KIA 059. Mining and mineral processing operations in Canada. Mineral Buletin MR 224. $23.70. Canadian minerals yearbook 1989. Review and outlook. Mineral Report 38. $47.95. Technology developments The Mintek Pyrosim Simulator Pyrosim is a computer program for the steady-state simulation of pyrometalurgical processes?.

Jan 1, 1990

By D. G. Krige

By use of models based on the South African gold-mining industry, analyses are made of the effects of changes in the mining tax structure on the .State's tax income from potential new mines; also on the percentage of such mines likely. to be proceeded with. The percentage is affected by the correlation between changes in taxation and in the flotation pay limits !or new mines. It is shown that the State stands to gain both directly and indirectly from raising the level of the capital allowance and from its extension to all mines; and that the reduced taxation resulting from a lowering of the discriminatory high tax formula for the gold mines, would, in respect of potential new mines, be compensated for by a significant increase in the percentage of such mines that would be proceeded with.

Jan 1, 1979

By D. Limpitlaw

As coal mining often results in the generation of acid mine drainage (AMD), careful planning and management of the water on such mines is required. A colliery in Mpumalanga recently sponsored independent research into the pollution-ameliorating potential of a natural wetland that has been receiving AMD for at least two decades. Samples of the sediment collected in the wetland were subjected to nine stages of sequential extraction in a determination of the distribution of the metal species present. The samples were then analysed for aluminium, iron, and manganese. The concentrations of sulphate-reducing bacteria (SRB) were also determined. The SRB concentration was found to increase with distance downstream (away from the source of pollution). An analysis of the sediment speciation data indicated that metal immobilization may be optimal in areas where the organic adsorption of metals is at its greatest. The analysis also provided evidence of the biogeochemical improvement of the water quality as the AMD passed through the wetland environment. The metal species present did not correlate strongly with the SRB populations; nor did the soluble species correlate with the species formed over long periods of time.

Jan 1, 1996

Book review Pearson, J. S. Ocean floor mining. Park Ridge (New Jersey), Noyes Data Corporation, 1975. 201 pp. NIM reports Report no. 308 A mineralogical study of gold particles in pulp residues from the Bracken Gold Mine. (7th Mar.,1968. Re-issued Oct. 1975.) Report no. 377 Examination of pulp samples, treated with cyanide, for coated gold.(7th Aug., 1968. Reissued Oct.1975.) Report no. 385 The determination of the nature of coatings on gold particles. (2nd Aug., 1968. Reissued Oct. 1975.) Report no. 452 The Purlex Process - a description of the pilot plant leading to the use of the process in South Africa. (13th Jan., 1969. Re-issued Oct. 1975.) Report no. 482 Review of work on the treatment of pegmatites. (9th Apr., 1969. Reissued Sep. 1975.) Report no. 1443 Gravity concentration tests on four samples from Tantalite Valley,S. W.A. (5th Jul., 1972. Re-issued Sep. 1975.) Report no. 1489 The breakage of S oderberg electrodes. (10th Nov., 1972. Re-issued Nov. 1975.) Report no. 1545 A mineralogical investigation of leach residues from the Blyvooruitzicht Gold Mine. (22nd May, 1973. Re-issued Nov. 1975.) Report no. 1583 Preliminary tests on winnowing for the recovery of mica. (12th Nov., 1973. Re-issued Sep. 1975.) Report no. 1652 The identification of diamonds from Premier, Finsch, and Jagersfontein Mines by statistical analysis of data obtained from instrumental neutron-activation analysis. Report no. 1723 The determination of zirconium and aluminium in zirconiumaluminium alloys. Report no. 1739 The determination of trace amounts of noble metals in sulphate media. Report no. 1771 The determination of silver, selenium, tellurium, antimony, tin, lead, and arsenic in anode sludges. Report no. 1772 A study of copper recovery by lime roasting and leaching. Corrigendum The Special Issue of Volume 76 of the Journal ('Recent Advances in Mineral Dressing, October 1975) should be corrected as follows. The South African Institute Of Mining And Metallurgy - Information On Membershlp The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical, Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. Die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie - Inligting Oor Lidmaatskap Die Instituut is in 1894 gestig as die Chemiese en MIetallurgiese Vereniging van ::!nid-Afrika. In 190-1is dit omvorm tot die Chemiese Metallurgiese en Mynbouvereniging van Sllid-Afrika en in 1956 het dit die Suid-Afrikaanse Instituut vir Mynbou en l\Ietallurgie geword.

Jan 2, 1976

By S R Grano

A fundamental model, which considers the subprocesses of particle collection by bubbles in flotation, is applied to two comprehensive flotation surveys in the rougher stages of C3 concentrator, PT Freeport Indonesia. The flotation surveys focused on the collection of: ? cell-by-cell and size-by-size metallurgical, ? cell hydrodynamic, and ? pulp and surface chemistry information. The two surveys were conducted at significantly different feed tonnages, giving rise to significantly different feed particle size distributions, pulp densities and mean pulp residence times. A series of model simulations are performed with the aim of quantifying changes in copper recovery, on both a size-by-size and unsized basis, with changes in values of the hydrodynamic parameters and hydrophobicity of the copper sulfide mineral. This was carried out in an effort to identify the most promising route to increase overall copper recovery in roughing. It was found that by increasing the hydrophobicity of the copper sulfide mineral surfaces it became possible to optimise cell hydrodynamics, which targeted increased fine (-12 µm) copper sulfide mineral recovery but without adversely affecting coarse (+150 µm) copper sulfide mineral recovery.

Jan 1, 2007

By M. J. A. Leal-Gomes

There is a set of settled ideas in the field of the mechanics of rock mass joints, that need a deep revision, after the last experimental works of several authors. In this paper, this theme is approached under several viewpoints, like the following ones: the essential influence of the mating or mismatching of rock joints on their strength (different strength models are applicable to these two situations, one leading preferably to normal scale effects, and the other to inverse scale effects); Patton's model is a bad formulation of the joint strength, whenever there is a dilation effect in the slidings (actually, the essential consideration of the amplitude of the roughess isn't made by any limit equilibrium model, like Patton's model); the joint strength increases as the width perpendicular to the sliding direction is reduced (previous works of other authors suggested the independence of the strength on that width); the reduction of the anisotropy of the roughness, as the sample symmetry and sample dimensions increase; there is no scale effect in the discontinuity mechanics, if there is no roughness heterogeneity; when only the same roughness and undulation orders are involved in the tests, shorter samples have larger peak displacements and lower shear stiffnesses than larger samples (usually, the contrary is admitted). For all these reasons, there isn't an easy correlation between the small scale tests and the natural large joint scale. Only "in situ" large scale tests have some representativeness. All the above mentioned questions are correlated to each other. Es gibt eine Menge eingewurzelter Ideen im Gebiet der Mechanik von Felsklüften, die, nach den letzten experimentellen Arbeiten von mehreren Verfassern, eine tiefe Überprüfung benötigen. In dieser Mitteilung, wird dieses Thema unter mehreren Blickpunkten angegangen, wie die folgenden: der wesentliche Einfluß des Zusammenpassens oder nicht Zusammenpassens von Gesteinsklüften auf ihre Festigkeit (verschiedene Festigkeitsmodelle sind auf diese zwei Situationen anwendbar, eins, das vorzugsweise zu normalen Maßstabseffekten führt, und das andere, das zu umgekehrten Maßstabseffekten führt); Pattons Modell ist eine schlechte Formulierung der Kluftfestigkeit, immer wenn es einen Dilatationseffekt in den Verschiebungen gibt (in Wahrheit, wird die wesentliche Berücksichtigung der Rauheitsamplitude von keinem Grenzgleichgewichtsmodell beachtet, wie Pattons Modell); die Kluftfestigkeit wächst wenn sich die Breite senkrecht zur Verschiebungsrichtung verringert (frühere Arbeiten anderer Verfasser suggerierten die Unabhängigkeit der Festigkeit von jener Breite); die Verringerung der Rauheitsanisotropìe, wenn die Probekörpersymmetrie und Probekörperabmessungen zunehmen; es gibt keinen Maßstabseffekt auf die Trennflächenmechanik, wenn es keine Rauhheitsheterogenität gibt; wenn nur die gleichen Rauheits- und Ondulationsgrößenordnungen in den Versuchen verwickelt sind, haben kürzere Probekörper größere Spitzenverschiebungen und geringere Schersteifigkeiten als größere Probekörper (gewöhnlich, wird das Gegenteil angenommen). Wegen aller dieser Gründe, gibt es keine einfache Korrelation zwischen den Versuchen im kleinen Maßstab und dem natürlichen großen Kluftmaßstab. Nur "in situ" Versuche im großen Maßstab sind einigermaßen repräsentativ. Alle die oben erwähnten Fragen hängen miteinander zusammen. Il y a un ensemble de des bien établies arrière-pensées idées dans le champ de la mécanique des discontinuités en massifs rocheux qui ont besoin d'une profonde revision, après les derniers travaux de divers auteurs. Dans cet article cette matière est abordée sous divers points de vue, comme les suivants: la signification essentiel de l'ajustement ou du désajustement des discontinuités dans leur résistance. Des différents modèles sont applicables à ces deux situations, une conduisant de préference à des effets d'échelle normaux et l'autre à des effets d'échelle inverses; le modèle de Patton est une mauvaise formulation de la résistance des joints quand il y a effet dilatant dans les glissement. En effet la contribuition essentielle de l'amplitude de la rugosité n'est pas consideré par aucun modèle d'équilibre limite comme le modèle de Patton; la résistance des joints croit au fur et à mesure que la largueur perpendiculaire à la direction de glissement est réduite. Des travaux antérieurs d'autres auteurs suggéraient que la résistance était indépendant de cette largueur; la réduction de l'anisotropie de rugosité au fur et à mesure que la symétrie et les

Jan 1, 2003

By P. R. Labrum, H. A. D. Kirsten

The literature on shotcrete is reviewed with the object of identifying aspects that have not been addressed specifically in terms of its structural performance and manufacture as applied to underground mines. The programme and results of a series of full-scale tests on mesh- and fibre-reinforced shotcrete panels are presented, from which it is concluded that fibre-reinforced shotcrete is competent, especialy at large deformations, and is equivalent in structural performance to mesh-reinforced shotcrete for a fibre content of 3 per cent by mass: furthermore, that the support design systems developed for mesh-reinforced shotcrete are directly applicable to fibre-reinforced shotcrete. The Q-NATM system for the design of temporary tunnel support is presented briefly as one such system. It provides for the integrity of the excavation to be considered in terms of its competence and displacement determinateness, and represents the first systematic procedure for the design of temporary tunnel support. Finally, the support designed on the basis of the Q-NATM system for the main and cross-cut tunnels on the production level in the proposed BA5 block cave at Premier Mine is presented as a practical example of the design of fibre-reinforced shotcrete as part of an overall support system.

Jan 1, 1990

By R. R. Mankowski

The work described in this paper is an attempt to increase present-day knowledge of fatigue in mine hoisting cables, particularly the internal energy loss arising from interwire/strand friction in a cable undergoing periodic non-planar transverse vibration. Such frictional energy loss is known to be one of the major influences limiting useful working life of hoisting cables in use today, and is responsible for the large capital outlay required to maintain the high safety factors prescribed by the mining industry. The experimental method employed identifies two mechanical characteristics of cables that are independent of amplitude and frequency, and are primarily attributed to the type of cable construction. Interest is focused the time rate of change of curvature as the major parameter influencing the internal damping mechanism. Empirical results confirm that amplitude and mode number play an important role in quantifying the internal losses, and also reveal that a critical radius of curvature exists below which damage due to vibration fatigue rises exponentialy to potentially high levels.

Jan 1, 1988

Project evaluation is completed through individual studies covering technical and financial aspects of the mine to market. These studies are completed at various levels of detail depending on where the project evaluation is in the project's life cycle. The competency of the studies varies in relation to the quality of data, level of the skills employed, control, management and reporting structure. The focus of this paper is managing elements of the study, looking at the cost of opportunity to influence the project, against the value added. Selection of the study manager and study teams is central to getting an integrated project evaluation addressing the correct issues completed on time. Retention of key personnel can reduce rework which, in turn, can reduce time and cost impacts. It is important to have a work breakdown structure at the outset so that the study teams have a common numbering and naming system that will integrate areas, equipment, budgets estimates and accounts. Having set up the evaluation groups and provided training in the study procedures, understanding the scope and schedule are vital elements in producing a project evaluation that addresses the opportunities and the risks of the final project. Arriving at an accurate capital budget requires integration of the research controlled through common systems. Project evaluation process must also address how the project is to be delivered.

Jan 1, 2007

By R. C. Hochreiter

The paper gives a technical review of the history, occurrence, mining, metallurgy, and end-uses of the platinum-group metals in South Africa, with most emphasis on platinum and palladium. The platinum industry has grown, from the first discovery of the metal in South Africa (in the central Transvaal) in 1923, to the present time, when the country is the largest producer of platinum 10the world, supplying almost 70 per cent of the platinum on the world market.

Jan 1, 1985

By A. H. Swart, M. F. Handley

Unplanned stope panel collapses occur on most near-surface and shallow mines in South Africa. Although these incidents often occur during blasting, they pose a major threat to the safety of underground workers and the economic extraction of orebodies. Most stope panel collapses occur due to excessive panel lengths that are not designed according to a systematic design procedure or methodology. Instead, panel lengths are often dictated by the equipment in use and by previous experience under similar conditions. Hence, a rock engineering design methodology for the design of stable stope panels between pillars is of vital importance for optimum safety and production in shallow mining operations. Using the proposed design methodology described in this paper, rock mechanics practitioners and mine planners should be able to identify and quantify the critical factors influencing the stability of stope panels. The critical factors should then be used as input to the design of stable stope panels that will provide the necessary safe environment for underground personnel working in stopes. The proposed design methodology is an iterative process, which includes aspects such as rock mass characterization, estimation of rock mass properties, identification of potential failure modes, consideration of appropriate stability analyses and other elements of the rock engineering design process. This process continues after implementation. During monitoring, new data should be included in the database and the design process repeated on a regular basis. Design approaches included in the proposed design methodology include empirical methods such as different rock mass classification methods, analytical methods such as elastic and Voussoir beam analyses, kinematic analyses, probabilistic analyses, and numerical analyses. Keywords: stability, stope panels, design methodology, hard rock mines, shallow mining operations

Jan 1, 2004

By L. G. Snyman

"South Africa is well endowed with a plethora of valuable minerals, as well as being of world renown for its significant ecological and cultural resources. The unfortunate reality is that these two important attributes often come into collision when developmental decisions are made. Robust environmental planning tools are required to guide such development in areas of heightened sensitivity. Environmental management frameworks are one of the tools that can attempt to achieve the desired developmental and ecological balance by utilizing early identification and mapping of sensitive ecosystems and resources to assist in pre-empting potential future land use conflicts. This paper unpacks the characteristics of environmental management frameworks and further investigates their potential, as well as its current design and implementation challenges. The findings show that environmental management frameworks have the potential to provide meaningful resource information to decision-makers on the opportunities and risks of developments in sensitive areas. They further provide a platform and process through which local stakeholders can voice their opinions and collectively drive the developmental priorities of the identified area.IntroductionAt the core of a harmonious and prosperous society is the balancing of a broad spectrum of needs, rights, and imperatives. As South Africa’s resource and energy needs expand, it becomes increasingly important to safeguard environmental rights and ensure sustainable development through creative measures. The State’s drive for accelerated development to meet the targets in the National Development Plan 2030 is contributing to the growth of invasive developments in previously undeveloped areas. The unfortunate reality is that the heightened tensions between rapid economic growth and environmental sustainability are threatening sensitive areas."

Jan 1, 2017

Council for 1998/99 President R.P. Mohring President Elect J.R. Dixon Vice Presidents Senior junior M.H. Rogers Dr L.A. Cramer Immediate Past President Honorary Treasurer Dr N.A. Barcza J.A. Cruise

Jan 1, 1985

By M. B. Algeo, R. H. A. Plaistowe

A method of forecasting the haulage trucks required for a large open-pit operation is described. Emphasis is placed on the effects of changes in planning and on the complexities of a mining operation that involves many benches and dumping areas.

Jan 1, 1979

By M. Rudman, L. Pullum, L. J. W. Graham

Centrifugal pumps are the workhorse of hydraulic conveying systems but their performance is derated when viscous non-Newtonian fluids, such as pastes and/or coarse solids are present. The reduced performance for purely viscous Newtonian fluids may be calculated using techniques such as the Hydraulic Institute method, but similar deration for non-Newtonian fluids is not so easy to apply. As part of the AMIRA P599 project investigating high concentration suspension pumping, centrifugal pump tests were systematically conducted on a wide range of non-Newtonian coarse particle suspensions. Suspension sup to 38% v/v of coarse particles with mean diameters in the range of 1.1 < d50< 3.4 mm suspended in carrier fluids with dynamic yield stresses of 0 < t?< 17.2 Pa and shear thinning indices in the range 0.35 < n< 0.79 were examined. Techniques such as the Hydraulic Institute de-ration method require a characteristic shear rate to be assigned before application with a non-Newtonian fluid, and a method based on pump geometry, fluid rheology and flow rate is proposed. This method predicts the dramatic characteristic reduction in head at low flow rates that is often observed and explains why larger pumps are relatively insensitive to this form of head deration. Head deration due to the presence of coarse particles in non-Newtonian carrier fluids is seen to follow similar trends to that of Newtonian suspensions and often dominates the total deration procedure.

Jan 1, 2007

By J. A. L. Napier

SYNOPSIS Many tabular mining problems can be modelled effectively by displacement-discontinuity techniques, which can be extended directly to represent fracturing on discrete planes and movements on planes of weakness. This paper presents a unified method for computing the energy changes that occur when multiple discontinuities intersect and are extended incrementally. It shows how this method can be used to deduce energy-release information for standard layout problems and, in addition, how the technique can be incorporated in numerical procedures based on the displacement-discontinuity method. Examples are given to demonstrate the effects of off-reef fracturing and the importance of stope-fault intersections during seismic events.

Jan 1, 1991

A prize awarded by the SAIMM for outstanding academic achievement by 4th-year and 5th-year diplomates at technikons was instituted several years ago. The Senior Vice-President, Mr J.D. Austin, accompanied by the Institute&apos;s Secretary, Mrs D. Gardner, attended a prize-awarding function in the form of a luncheon at the Hotel School of the Technikon Witwatersrand on the 25th May.

Jan 1, 1984

A theory is presented providing a concise mathematical description of the performance of a percussive rockdrill in terms of its principal mechanical dimensions. The theory defines the relationships between the values of thrust required to produce optimum rates of penetration at different throttle air pressures in terms of the piston areas and derives an equation for the prediction of these rates. An analysis of drillsteel life and bit wear is also made.

By R. M. G. Machunter

The dynamic behaviour of plant circuits and the available instrumentation determine the control strategies that are appropriate for the duty of the mineral separation plant. Although steady state modelling is appropriate to provide the main requirements of grade and throughput capability of a plant, it is the dynamic characteristics that determine the tolerance of the plant to disturbances and also its controller ability. This paper explores these issues with respect to the additional use of dynamic modelling to achieve these objectives.

Jan 1, 2007