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Mr R. w.o. Kersten joined the Geological Department of Anglovaal in 1964 after obtaining a B.Sc. Honours degree in Geology at the University of Pretoria. Mr H.G. Mosenthal was educated at Pretoria Boys' High School and the University of the Witwatersrand. He holds a B.Sc. in Mining Engineering and a GDE.

Jan 1, 1985

A banquet, attended by 467 members and visitors, was held at the Wanderers Club, Johannesburg, at 8 p.m. on Friday, 21st March, 1969, to celebrate the 75th Anniversary of the founding of the Institute. Introduction of Dr Carel de Wet R. C. J. Goode (President) Dames en here: Ons het 'n aantal vooraanstaande gaste in ons midde vanaand en mnr Maxwell sal u later meer van hulle vertel. Dit is my aangename plig om u voor te stel aan sy Edele, die Minister van Mynwese, van Beplanning, en van Gesondheid, Dr de Wet en sy gade, mev de Wet. Sy Edele Dr de Wet het geen bekendstelling nodig nie-alhoewel hy ons minister vir slegs die afgelope twee jaar is, het hy reeds talle funksies van ons Mynbedryf bygewoon en het baie vriende gemaak onder ons. Hy het homself baie bemind onder ons gemaak toe hy Wes-Driefontein onlangs besoek het om hulle ondersteuning en aanmoediging aan te bied in hulle uur van nood. The Honourable Dr de Wet was born in the Free State. He is a grandson of that very famous general Christiaan de Wet, who caused so much pain to the British forces and for so many months so successfully eluded them in the Transvaal and Orange Free State. He was educated at both the Pretoria and Witwatersrand Universities. He first practised medicine at Boksburg and then moved to Vanderbijlpark, so you see he has an early association with gold mining on the Witwatersrand, and in moving to the Vereeniging-Vanderbijlpark district he became closely involved in our coal mining and metallurgical industries. South Africa's first steel was poured from a l0-ton open hearth furnace belonging to the Union Steel Corporation in Vereeniging in 1913. Dr de Wet has been mayor of Vanderbijlpark and for several years has been their member of parliament. More recently, the Honourable Dr de Wet has filled with great honour that most important office of Ambassador for the Republic of South Africa in London. At present he wears two hats, in that he is Minister of Planning and of Health, but more important is his cloak, that of Minister of Mines, which I trust offers him the greatest comfort. To fulfill these three arduous tasks must demand of him a terrific devotion to duty, and in doing this he carries on that loyal tradition of service to his fatherland so evident in his grandfather. Dames en here, dit is vir my 'n groot genoeë om Sy Edele Dr de Wette vra om 'n heildronk in te stel op die Instituut vir Mynwese en Metallurgie. Toast to the Institute of Mining and Metallurgy Dr the Honourable C. de Wet (Minister of Mines): Mr President, ladies and gentlemen, Mr President you have introduced me gracefully to this distinguished company and I am appreciative of your remarks. I am fully conscious of the responsibilities that devolve upon me as Minister of Mines in a country where mining makes so vital a contribution to economic progress and development and has, in fact, laid much of the foundation on which our present proud edifice is built. The achievements of the mining and metallurgical industry in its diversified activities arouse feelings equivalent to paternal pride, but let me speedily add that in considering any family relationship that may exist, the Minister of Mines should not be regarded in the role either of a fairy godmother or an indulgent father.

By More-O&apos, R. C. Ferrall, J. W. Wilson

SYNOPSIS The theory of elasticity has been shown to provide a means of determining the stresses and displacements induced by mining in deep level hard rock mines. This theory has been incorporated into an electrical resistance analogue on which the plane of a reef or ore-body can be modelled to enable the rapid determination of stresses and displacements at points in the plane of the reef. This electrical analogue has been used to determine energy release rates caused by scattered mining, which, to some extent, is a measure of the degree of hangingwall fracture. A correlation between predicted energy release rates and actual underground conditions in stopes in the O.F.S. goldfields has been encouraging enough to define parameters on which future stoping layouts can be based. The use of the elastic theory through the analogue has been extended to the assessment of the influence of stoping operations on off-reef excavations. Underground conditions at damaged and undamaged areas have been compared with predicted elastic stresses at the positions under review, resulting in the derivation of design parameters for use in siting off-reef excavations in the prevailing geological conditions in the O.F.S. and Klerksdorp goldfields. The analogue has also been used to assess the vulnerability of certain un mined dykes to bursting. Correlations between stresses induced on dykes by stoping and dyke behaviour underground has enabled critical stress levels to be determined for several persistent dykes occurring in the O.F.S. and Klerksdorp goldfields. A number of long and short term planning projects at mines operating in the Anglo American Corporation and General Mining and Finance Groups are described, where the data derived from the electrical resistance analogue is processed by computer programmes and assessed on the strength of the design factors derived from the correlation of field work and the elastic theory.

Jan 1, 1970

The following papers were presented at the colloquium* on `Mining methods and economics for improved coal extraction, and coal processing and preparation', which was held in Witbank on 3rd and 4th October, 1979. Review of Mining Methods for Improved Extraction of Coal, by P. King, of Gold Fields of South Africa, for¬merly of the Chamber of Mines of South Africa. The Application of Continuous Miners in South African Coal Mines, by J. D. Inch, Bosjesspruit Colliery, I. Brumby, South Witbank Coal Mine Ltd, J. D. Stone, Matla Coal Ltd, and C. J. Beukes, Usutu Colliers Ltd. Longwall Mining Experience at Coalbrook Collieries, by P. G. Henderson, General Mining and Finance Corporation Limited (with a contribution by C. J. Cloete, Sigma Colliery, Sasol I). Pillar Design in Coal Mines, by Dr H. Wagner, Chamber of Mines Research Laboratories. Open-cast Coal Mining at Kriel Colliery, by I. Buchan, L. F. Baars, and C. S. Northcote, Anglo Power Colliery, Kriel Division (with a contribution by M. F. Pleming, General Mining Coal Division). Richards Bay Coal Terminal, by B. Dunne, Richards Bay Coal Terminal. Coal Preparation in South Africa - a General Review,

Jan 1, 1979

By S. Kahraman

P-wave velocity measurements were carried out on 22 large limestone blocks in a stone processing plant. In the laboratory, P-wave velocity of core samples was measured to obtain intact rock velocity. The square root of the ratio of the velocity of the large stone block to the velocity of the core specimen was called the velocity ratio index (VRI) and a quality classification for large building stones was suggested. In addition, the applicability of the established classification to stone cutting with gang saws was checked. It was concluded that the quality classification and estimation of slab production efficiency of the building stones can easily be made by ultrasonic measurements. However, the study was carried out only in limestone. Further study must be conducted to check the validity of the obtained results for the other rock types.

Jan 1, 2007

By Neal Harries

The monitoring of rock slopes is a common procedure in the management of hazards associated with slope instability. Slope stability radar has become widely accepted as the state-of-the-art method for management of hazards associated with unstable slopes in open pit mines. This is confirmed by the rapid adoption of the technology since inception in mid 2003, with over 70 GroundProbe slope stability radars now in use at open pit operations throughout the World. The use of a monitoring system such as slope radar to identify slope hazards is only part of the solution to minimise the consequences associated with slope instability. The presence of the hazard must also be effectively communicated to the mine personnel, so that the correct response to the hazard can be enacted, and the risk mitigated to an acceptable level. In some surface mines, due to the geotechnical characteristics of the rock mass, hazards can develop rapidly; with slopes progressing from stability to ultimate collapse in just hours. In these situations, it is vital that efficient systems are developed to evacuate the area of the pit affected. Such a system has been developed by GroundProbe in South Africa, with the vital driving force for the project being provided by the Anglo Platinum Mogalakwena mine operation based at Mokopane. The mine based development of the system was perceived as an essential aspect in the development of the successful system. From an early stage, the mine provided essential input on both hardware and software developments to allow the system to be rapidly integrated into the mining operation. This paper describes the pit evacuation alarm system that was developed and discussed the benefits obtained from a mine based development program.

Jan 1, 2008

By P. J. van Staden, T. W. Walker

The Minfurn is a novel carbon-regeneration furnace developed at Mintek. It combines the advantages of direct resistive heating in a vertical-tube furnace with those of continuous operation, in a furnace whose capital, operating, and maintenance costs compare favourably with those of conventional rotary kilns. After successful tests under experimental conditions on carbons containing different contaminants, a 3 kg/h unit was installed on the carbon-in-pulp (CIP) plant at the Klipwal Gold Mine near Piet Retief, where it has been operating at, on average, 123 per cent of its design capacity. Since the installation of the Minfurn, monthly average losses of dissolved gold of less than 0,02 p.p.m. have been maintained for several successive months for the first time since January 1989. It is also possible that the monthly average residue values have been reduced. Further improvements to the carbon circuit are possible, and the possibility of making further savings by a reduction in the carbon-throughput rate still needs to be investigated. The mathematical modeling of the furnace has progressed to the stage where the future scale-up and design of the Minfurn can be carried out by simulation of the performance of different designs, and choosing the design that yields the desired performance.

Jan 1, 1993

By A. S. Macfarlane

Western Deep Levels (North) is a deeplevel, longwall gold mine. Severe strata control problems and high rates of elastic closure, resulting in high rates of energy release, are associated with mining at depths of up to 3 500 metres. To assist in controlling these aspects of mine design and safety, a waste backfilling system has been designed and commissioned. The integration of such a system into an existing, producing longwall brings many problems of logistics, organization, planning and control. It is the purpose of this paper to examine these aspects of fill management, and to describe some of the practical problems involved with the integration of this project into the mining environment. Although many of the rock mechanics and soil mechanics aspects of backfilling systems are common there are specific problems involved which apply to longwall systems. Very strict guidelines are required for planning personnel to design their backfilling systems for a particular situation. These aspects are examined, and basic models developed which can be used without the necessity of comprehensive input from rock mechanics. A summary of the financial implications is included, and these are examined with regard to possible future applications and expansion of waste filling.

Jan 1, 1988

By D. P. Power

The development of an accounting code for the metallurgical industry has been debated for many years. Following the series of tumultuous economic events in the nineties and earlier this century that have affected business, there was much need for legislation to be passed to minimize potential risk. One of the consequences to affect the mining industry was the enhancement of existing geological codes for reporting. In parallel the sponsors of AMIRA have taken the brave step to develop a generic code for metal accounting that embraces the full gamut of industry. In this paper the code will be reviewed in the context of metallurgical accounting as it applies to coal preparation. This paper provides the background for this development and an insight into the mechanism for the debate for the generation of this code. The key elements of the code as it applies to the coal industry are explained but most importantly the key opportunities are highlighted.

Jan 1, 2010

A method, based on the macroscopic population balance equation allowing the dynamic simulation of a multistage adsorption plant given an arbitrary rate expression, is described. The partial differential equations resulting from this method are simplified using the method of characteristics. The simplified equations can then be solved using standard ODE integration techniques. The procedure is illustrated by means of data typical of a CIP application. Requirements for data structures which allow the incorporation of the carbon-in-pulp (CIP) model (and other unit models) into a general metallurgical simulator are described. Based on these considerations, it is concluded that more generality in the description of distributed quantities such as loading and particle size is provided by the use of mass density at fixed class boundaries, rather than discrete masses within fixed classes as has hitherto been used by ore-dressing simulators.

Jan 1, 1987

By H. C. Voges

An account is given of the tests being conducted by Iscor on the following processes for the beneficiation of coal fines: froth flotation, gravity separation, heavy-medium separation, and pneumatic and column flotation. The coals used in the tests came from the Durnacol, Tshikondeni, Grootegeluk, and Hlobane collieries. The problems involved in the dewatering of fine products are stressed. From a theoretical study of the efficiencies that should be possible for a hypothetical South African coal, it is concluded that future fines-beneficiation plants in South Africa may use standard heavy-medium cyclones for coal down to 1 mm in size, fines heavy-medium separation for the 1 mm to 450 µm fraction, and column or pneumatic flotation for the minus 450 µm fines.

Jan 1, 1991

By K. Grossauer, W. Schubert

For tunnelling in poor and heterogeneous ground a reliable on-site short-term prediction is required to allow a safe and economical construction. With the use of absolute displacement monitoring data and advanced software for evaluation of the data in combination with a routine update of the geological model a considerable increase in the reliability of the short-term prediction could be achieved. The paper deals with theoretical considerations, numerical studies and case histories from alpine tunnels in heterogeneous rock. Tunnelbau in schlechtem und heterogenem Gebirge erfordert auf der Baustelle eine verlaessliche Kurzzeitprognose, um ein sicheres und wirtschaftliches Bauwerk gewaehrleisten zu können. Die Verwendung von absoluten Verschiebungsmessdaten und deren Auswertung mit Hilfe von hoch entwickelten Softwareprogrammen in Kombination mit einer laufenden Aktualisierung des Gebirgsmodells ermöglicht eine erhebliche Erhöhung der Verlässlichkeit von Kurzzeitprognosen. Dieser Beitrag beschäftigt sich mit theoretischen Ansätzen, numerischen Modellen und Fallstudien von Tunnelvortrieben in heterogenem Gebirge. La construction de tunnels dans la montagne hétérogène de faible résistance exige un pronostic fiable à court terme sur le chantier, afin de pouvoir garantir un ouvrage sûr et économique. L'utilisation des données de mesure de décalage absolues et de leur évaluation à l'aide de logiciels sophistiqués en combinaison avec une mise à jour courante du modèle de la montagne permet une augmentation considérable de la fiabilité des pronostics à court terme. Cette contribution présente des approches théoriques, des modèles numériques et de cas pratiques de progressions de tunnels dans des montagnes hétérogènes.

Jan 1, 2003

By R. W. Ottermann, N. D. L. Burger, A. J. von Wielligh, P. R. de Wet, J. L. Steyn

Underwind and overwind protection system concepts for mine hoist shafts were developed in conjunction with and for the Safety in Mines Research Advisory Committee (SIMRAC). End-of-wind operation of mine hoists is the most hazardous aspect of mine hoisting, carrying the highest risk of loss of life, injuries to workers and loss of production. Systems operating mechanically and with local actuation were developed. This was done in order to remove the increased risk associated with dependency on remote or external energy and information supply associated with most existing protection systems. The proposed underwind protection system concept absorbs the energy of motion of a conveyance overrunning the design lower limit of travel by drawing a metal strip through a set of rollers. This action causes dynamic cyclic plastic bending of the strip material that converts the kinetic and potential energy of the conveyance into strain energy of the metal. In the concept design a pair of cable slings attached to the strips catch the overrunning conveyance and transfer the retardation force. The proposed overwind protection system concept absorbs the energy of motion of a conveyance overrunning the design upper limit of travel by early detaching of the conveyance from the hoist cable. This detaching is carried out via an additional humble hook activation mechanism fitted at a sufficient height below the spectacle plate to allow the conveyance to retard to standstill under gravity before it would crash into the spectacle plate. The conveyance so brought to rest is prevented from falling by means of jack catches on the conveyance interacting with a rack (toothed profile) fitted on the guide rails in the retardation zone. Scale models (1:10 scale) of both protection systems were designed for conformance with established retardation standards. The retardation standards were limited by the requirement of passenger safety in retarding cages. The models were then built and tested in a 1:10 scale shaft model. Retardation performance close to the required levels was achieved. The retardation distance required should allow such systems to be retrofitted to most existing shafts. Given the simplicity and robustness of the designs

Jan 1, 2003

By B. Jack, A. Vervoort

During pillar extraction, sidewall fracturing and spalling at some collieries constitute a severe stratacontrol problem. In order to obtain a better understanding of this phenomenon, a survey of pillar corner conditions before and during pillar extraction was conducted at one particular site. For the various successive mining steps, the vertical stresses on the pillar corners were calculated by use of a three-dimensional boundary element program. A significant correlation was found between the calculated vertical stress prior to the extraction of the panel and the sidewall conditions. During the extraction of the panel, a significant deterioration of the sidewall conditions at a pillar occurred only when the adjacent pillar was mined, causing an increase in vertical stress on the remaining pillar.

Jan 1, 1992

By G. S. Hansford, J. W. de Kock, C. D. Levy

Rheological measurements on pulps from South African gold mines by G. s. HANSFORD, Ph.D. (Pennsylvania), M.Sc. (Cape Town), C. D. LEVY, B.Sc. (Eng.), and J. W. DE KOCK, Ph.D. (Cantab.), B.Sc. (A.I.C.) (Visitors) A method is described for the determination of the rheological parameters of a fast-settling slurry with conventional viscometric measuring equipment. The effect of concentration, temperature, and pH on these parameters is investigated. The results agree with those obtained by previous workers using different viscometers, but this method allows a more detailed characterization of all the properties. From a literature survey, two semi-empirical equations were found that allow the effect of concentration, temperature, or pH on the rheological parameters to be correlated.

Jan 3, 1976

By J. K. E. Douglas

Brigadier Ralph Shelton Griffin Stokes D.S.O., C.B.E., M.C., who died in England on 24th February, 1979, at the age of 96 years, was one of the most colourful personalities in South African mining history. After the South African War, in which he served as a trooper, he joined the Crown Reef Mine as an assistant assayer (1902), and was to serve the mines of the Corner House Group intermittently for the next 57 years until his retirement in 1959.

Jan 1, 1979

By W. L. Van Heerden

In situ complete stress-strain characteristics of large coal specimens by W. L. VAN HEERDEN, B.Sc. Hons. (Pret.) (Visitor) The significance of ;n situ tests on large coal specimens is briefly reviewed. Tests aimed at obtaining complete stress-strain characteristics of large coal specimens with high width-to-height ratios are described. A formula for the relationship between strength and width-to-height ratios of coal pillars is proposed, and the influence of width to- height ratios on the deformation characteristics of pillars is discussed.

By C. G. Verkerk

The paper discusses the transport and rheological characteristics of high concentration slurries or pastes for backfill purposes. The influence of pipe size, particle size distribution, additives, coarse material and mass concentration on these characteristics is addressed.

Jan 1, 1988

By H. Wagner

It is a great privilege for me to have been asked to present the closing address to this most successful symposium on backfill in the South African mining industry. When I accepted this invitation I did not fully appreciate the tremendous progress made on most aspects of backfilling in the last few years. The number and quality of papers presented at this symposium bear testimony to the mining industry's determination and success in introducing backfill in underground mines to improve strata control and environmental conditions, and to provide better protection to mineworkers against the hazards of rockbursts and rockfalls. Many contributions demonstrated that these benefits can be achieved at a reasonable cost, and in some instances improved grade and higher rate of face advance result in improved economics. In my closing address I will attempt to summarize the progress made in the various aspects of backfilling underground workings and to identify those areas which, in my opinion, require further attention and effort. I will undertake this review under the following main headings: ? fundamentals of backfilling; ? design of backfill systems; ? operation of backfill systems; ? control of backfill systems; and other aspects of backfill systems.

Jan 1, 1988

By R. Kosmicki

Wet end components of centrifugal slurry pumps used in the hydraulic transport of solids are subject to substantial erosive wear. Accurate prediction of the casing wear rate and location for a particular duty is beneficial for correct pump selection and design, maintenance planning, and elimination of emergency shutdowns. CFD multiphase simulation using the Eulerian-Eulerian approach is being applied successfully to determine the velocity fields and solids concentration in the centrifugal pump, allowing for accurate predictions of casing wear patterns resulting from sliding abrasive wear. Simulation results for various single domain and multi-domain (multistage) multiphase simulations are discussed. Emphasis is placed on results from a 3-dimensional, multi-stage transient, multiphase simulation and comparison to field data.

Jan 1, 2007