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By J. J. Geldenhuys

Premier of the North-West Province, Mr Molefe, foreign dignitaries and guests, ladies and gentlemen. It is a pleasure and also a special honour for me to have been invited here this morning to make this address. The xv Congress of the Council of Mining and Metallurgical Institutions is, by its very nature, an extremely important event for the international minerals industry. But I believe that this specific Congress assumes an even greater significance because of the profound and far-reaching changes that have taken place in South Africa this year. These are exhilarating times, a period when so much in our country has altered and when so much has to be done so quickly to build positively on our bold political decisions.

Jan 1, 1994

By B. M. Van Vliet

SYNOPSIS This paper outlines the principles involved in the regeneration of activated carbon for renewed use in the recovery of precious metals or the purification of water. While chemical methods are effective in restoring the activity of spent activated carbon containing only single or defined adsorbates, thermal methods have to be used when the spent carbon is loaded with a heterogeneous mixture of adsorbates such as those normally present in industrial process streams or effluents. The steps involved in thermal regeneration are described, together with the operating conditions that can be controlled to give the required degree of activation. Finally, an account is given of the structural changes that occur in a new or spent activated carbon during thermal treatment.

Jan 1, 1991

By L. M. Falcon

Cassiterite is considered to be the only economically significant tin mineral in the earth's crust, and in its purest form has a tin content of 78,6 per cent. South Africa has limited deposits of the mineral, and by its exploitation contributes about 2 per cent of the world's production. This paper gives a brief history of tin mining in South Africa, which dates back almost 3000 years. Over the intervening years, many tin-mining operations have flourished and as quickly disappeared. At present there are only three tin mines in operation, and a description is given of the methods of mining, concentrating, and smelting that are used. The properties and uses of tin are listed, together with relevant statistics.

Jan 1, 1985

Blasting in a gold mine has to satisfy the following set of techno economic conditions: good fragmentation, minimum stopped width, minimum number of rock falls, cost effectiveness. Results of a comparative study of the performance of a Low Density Anfo (LDA) and a conventional Anfo (ANFEX) are discussed. LDA appears to be more cost effective. The same borehole volume can be charged with material of reduced specific gravity. The velocity of detonation (VOD) is increased in the case of LDA resulting in more breakage as a result of shock energy than from the energy in the gas phase. This leads to less damage to the excavation and more favourable breakage of the excavated rock. As a result the overall economics of the mining operation is improved.

Jan 1, 1995

By I. R. M. Chaston

A full and detailed description is given of the dense-medium cyclone plants used in Africa for the recovery of diamonds.

By Y. Zhang, F. Zhu, Y. Zhao, L. Dong, Y. Li

In order to obtain a more suitable separation medium for fine coal, in this paper a pulsed fluidised bed was used to measure the pressure fluctuation, density characteristics, bubble diameter and rising velocity of Geldart A and B particles in the bed by controlling the pulsation frequency and gas velocity, in order to study the fluidisation effect and two-phase distribution of the bed. The results indicated that with the increase of pulsation frequency, the breakthrough point on the fluidisation characteristic curve caused by particle adhesion disappeared, and there was an optimal frequency, which made the minimum fluidisation velocity of particles reach the minimum. In addition, the bubble rising velocity was also simulated. The relationship between them was established using a model, and the error was within 5%. This provides an effective way to predict the bubble velocity, study the distribution of bubble phase, and improve the stability of bed density. Keywords：Frequency, flow velocity, pressure fluctuation, bed density, bubble

Jan 1, 2020

By A. Marek

The safe and optimal installation of roof support remains one of the biggest challenges in underground mining today. Traditional hand-held, roofbolt installation in conventional mining has been replaced, in a lot of mining operations, by mechanized equipment. This was a first step to moving the operators out of the unsafe working environment and a start on the trend toward a changed support regime in mechanized mining. However, the challenge of handling of the drill steel itself, as well as inserting resin cartridges and bolts, remains a major hazard and the cause of many lost-time injuries. The paper describes and discusses developments in this area, of mechanized bolting and on-board automation, presenting solutions to known problems, achievements to date, and future developments. The solutions presented will identify with addressing customer needs while touching on possibilities for further technology changes, keeping focus on the safety aspect for operators and the need to bring the operators even further away from the unsafe working environment. The-state-of-the-art technology in mechanized bolting equipment is presented and a brief outlook on the past, current, and future developments is given.

Jan 1, 2012

By M. C. van Eeden, R. Vermeulen, K. B. Le Bron

This paper presents the lessons learnt during the transition from an open pit method to a sub-level open stoping method at the Koidu Limited kimberlite pipe. These learnings may assist other mines with planning, both from a practical implementation perspective (layout, charging up challenges), and a method for estimating potential dilution and stability challenges associated with the interaction between the surface and underground excavations. Predictive geotechnical stability modelling was successfully applied to highlight potential failure zones, which allowed modification and enhancement of the mining layouts and quantification of the potential dilution of the kimberlite from indicative instabilities.

Sep 1, 2025

By W. C. Joughin

Modern soil mechanics is generally considered to have begun in 1925, when Karl Terzaghi published his book Erdbaumechanik auf bodenphysikalischer Grundlage (Earthwork Mechanics based on the Physics of Soils). These theories were applied to rocks more than 20 years later and the science of rock mechanics became established. Methods of analysis and design have been introduced and applied, and have evolved over time. More recently, the rapid growth in computing power has resulted in more sophisticated analyses, and together with improved monitoring techniques, our understanding of geomechanics has grown considerably. Despite this, geotechnical failures with major consequences still do occur. This is partly due to failure to transfer and apply the knowledge that has been gained, but also there are aspects of geomechanics that are not well understood.

Sep 1, 2023

By V. C. Robinson

INTRODUCTION Most presidential addresses are in the nature of a review of some specific topic and this will be no different. In thinking about the subjects which might be suitable for this address I decided that as next month will see my retirement from the gold mining industry I might review the four decades since I started in the industry in 1929. These four decades have been more than usually in',~resting and exciting. They have covered a period when the price of gold increased from the old figure of 84/- an ounce to the price of $35 an ounce today, taking in on the way at least two periods of premium sales from which the producer benefitted. The industry in these four decades has survived the most totally destructive war in history and has seen fundamental changes in the political, economic and governmental life of South Africa. There have been great technological changes and improvements, some of which I shall refer to later, and in addition there have been profound changes in the relations between employer and employee in the industry which have affected not only the economy of the industry but the traditional thinking of both management and labour. I believe that the address presented to this Institute on the occasion of its 75th Anniversary by Mr Goode covered more than adequately the history of the Institute and the part it has played in the mining industry of South Africa. It would be merely repetitive, therefore, to discuss the affairs of the Institute of Mining and Metallurgy. Having said this, however, it is also necessary to point out that the history of the Institute is, and always will be, an important record of the history of mining in South Africa. There are many facets, however, on which we ought to look back and to re-examine. One of the most rewarding, but at the same time one of the dullest, places to look for historical facts is in the annual reports of the Chamber of Mines. I suppose that some of the dullest of these have been the reports for which paragraphs have been prepared by me personally. The notes which follow do not claim to be anything like a full record of this exciting period. RISE AND FALL OF THE GOLD MINING INDUSTRY In talking about the mining industry of South Africa it is inevitable that one talks, particularly in the historical sense, about the gold mining industry - an industry of fundamental importance which has made South Africa what it is and which has been dying since the early part of this century. In Table I is shown the progress of the gold mining industry measured by its output of ounces of fine gold from the beginning of operations until the end of 1969, and if you are interested in the productivity of the men who work this industry the table, composed entirely from figures set out in the Chamber's annual reports, also shows the production of gold expressed as fine ounces per European and fine ounces per Bantu worker over a long period. If you are still minded to think of this industry as dying then the last column in the table shows how uranium has played such a vital part in the prosperity of the country.

By P. Stevenson

Correlations for the critical velocity needed to hydraulically convey particles in horizontal, or near-horizontal, pipes are either explicitly dependent upon the shear stress imparted by the fluid upon the surface of the particle bed, or require a velocity and hydraulic diameter. Often such approaches are modified to account for pipe inclination by the introduction of simple factors. However, we assert that the physics that underpins the hydraulic conveying of particles in steep pipes (such as a directionally drilled oil well) is dissimilar to that which governs particle behaviour in horizontal pipes. In steeply inclined systems, a sliding sediment induces an upward counter flow and hence an autogenous contribution to the shear rate. The physics underpinning particle hydraulic conveying in steep systems is explored using the separation results of Laskovski et al.10

Jan 1, 2007

By R. Hoare

TSG Consulting works with many of the major global mining companies using simulation modelling as an integral component in their development team's processes to determine which combination of infrastructure options, operating performance and operating rules best achieve project goals. All systems can be divided into a series of subprocesses. Conventional management and design practices focus on the optimisation of these system components. However, the interaction between subprocesses means that improvements made to the individual components do not necessarily translate into total system performance improvement. TSG Consulting advocates a `total integrated system approach' to understanding the behaviour and performance of complex interacting systems. In a constraint-based integrated set of processes, the instantaneous system capacity is limited by the subsystem component capacity that is the bottleneck at that point in time. Additionally, real world stochastic and dynamic influences tend to have knock-on effects across subsystem boundaries. This necessitates the requirement for simulation modelling to develop and validate solutions that are sufficiently robust to deliver sustainable outcomes. The key to maximising production is to understand the causes and effects the inherent variability has on component performance, subprocess performance and most importantly, the total integrated system performance. The correct use of simulation modelling techniques allows study teams to evaluate the relative merits of different capacity enhancement proposals. Put simply, when done well, simulation modelling provides a quantitative and rational process to enhance the knowledge and insight needed to make informed decisions.

Jan 1, 2007

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisym-metric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing the charge towards the back of the trim blast results in a much more significant decrease in back damage than altering the timing. The model demonstrates how separation along the weaker planes in a jointed rock can coarsen the fragmentation, leading to inefficient beneficiation, and extends the damage to a distance of at least twice the burden behind from the blasthole, severely compromising the wall stability.

Jan 1, 2012

The exciting history of gold mining in South Africa haR been told in many different ways - in books, plays, and films, and on radio. But now, there's a new and far more lively way to find out about it and that is by actually participating in living history. Your invitation to go back in time will not take you much further from the centre of Johannesburg than the late-afternoon stretch of the shadows of the skyscrapers. The Gold Mine Museum - a new venture by the Chamber of Mines - brings back all the colour and romance of mining a century ago, and reminders of some of the hardships too. This is not an ordinary museum, but one of the most modem attempts in the world to make the past come to life.

Jan 1, 1980

The quality of life in many countries of both the developed and the developing world is strongly affected by the products and processes of mining industries. The first Issue in this new series brings together a set of review articles by leading authorities in the field which, taken together, provide a thorough and detailed survey of many of the key topics of current concern relating to the environmental impact of mining. The level of treatment of most topics is at first introductory but evolves through to the advanced level of current research, backed up by extensive citations of relevant primary literature and other sources. Thus the Issue as a whole will be found equally valuable by students of environmental science and those actively engaged in research related to this theme.

Jan 1, 1995

The value of incentive payments in the mining industry by K. SMITH, A.R.S.M., B.Sc. (London) (Member) This paper reviews the history of incentive payments in the mining industry, and gives some indication of the magnitude of improvement that has been achieved by this means in the past. The objective is to promote a more general belief in the efficacy of these methods, and thus to encourage their wider and more effective application by mining engineers in general, and by the rising generation in particular. It is concluded, from a consideration of current productivity levels in the gold-mining industry (still South Africa's leading revenue earner), that further substantial improvement can be achieved by a better understanding of the time-tested principles of incentive payments.

Jan 5, 1974

By J. J. Van Rensburg

The commissioning of a test facility for the calibration of anemometers by J. J. VAN RENSBURG (Student Member). After the erection of a commercially produced open-jet wind tunnel for the calibration of the anemometers used in mine ventilation, the wind tunnel was calibrated for routine use. There is a choice of five orifice plates. which, together with a variable-speed fan, can give a measurable range of air velocities in the test section from about 0,05 to 35 m/so The orifice plates were calibrated against a standard pitot tube, and it is now necessary only to measure the pressure drop across an orifice plate and to read off, from a set of graphs, the true outlet velocity in the test section. The paper describes the underlying theory and the test results.

Jan 4, 1975

By D. A. Viljoen

The ore mined at Black Mountain is of a complex nature, being composed of both magnetic and massive sulphides, which have greatly varying metal values. Because of this, there is need for a rapid method of assaying for the continuous monitoring and control of the process streams, and the Outokompu Courier onstream analysis system and the Proscon process-control computer systems have therefore been installed. Geostatistics In view of the continuing demand, the Department of Mining and Mineral Sciences in association with Special Courses Division, Department of Adult Education and Extramural Studies, both of the University of Leeds, will offer two further courses on A Practical Introduction to Geostatistics in 1981, each covering ten working days. The courses will run from 30th March to 10th April and 14th to 25th September.

Jan 1, 1980

By A. H. Mokken, G. K. I. Blendulf, N. R. Cowin, K. A. G. Blendulf

A study, by continuous monitoring of particle size in the cyclone overflow, of factors influencing run-of-mine mill performance by A. H. MOKKEN, B.Sc. (Eng.) (Rand) (Fellow), G. K. I. BLENDULF M.Sc. (Stockholm) (Member), K. A. G. BLENDULF, Dipl. (Min & Met) (Visitor), and N. R. COWIN, B.Sc. (Min. Tech.) (Visitor) An account is given of an investigation of the use of a continuous particle-size monitor - the PSM-IOO. The monitor system, in addition to showing marked variations in grinding fineness over short periods of time, particularly after stopping and re-starting the feed to the mill, has indicated weaknesses in accepted mill operating practice. The main potential of the system is the opportunity it has provided for almost complete automation of the milling circuit.

Jan 5, 1975

By P. J. How, T. O. Hagan, M. F. Handley

Inelastic deformation of highly stressed rock in deep mines needs to be quantified in both time and space. Since most deformation occurs by shear, continuous monitoring of discontinuities in the rock from boreholes holds promise. The casing. Al interpretations of shear movements are based on a simple relation between shear displacement and the resulting change in tilt of the sensor. A prototype has been constructed and has undergone laboratory trials with satisfactory results. Underground trials will commence shortly. The instrument as designed has the potential for other applications, both in the civil-engineering and mining industries. paper describes an instrument that is both cheap and reliable, and capable of monitoring such shear movements continuously. The principle of operation is based on two capacitive gravity sensors mounted orthogonaly to each other in a sealed aluminum

Jan 1, 1988