Search Documents

By G. C. S. Burns

"A system has been developed to simulate the mining of the Mufulira orebody. The main output from the system is a picture-gram from which the start date and effective life of all proposed mining faces can be measured. This information provides schedule dates for the completion of major capital development projects and stope preparation activities.The orebody must be divided horizontally into main levels and vertically into blocks of equal interval. Ore reserves are defined by specifying the tonnage contained in each block and main level. Mining faces are defined by their co-ordinates, and may themselves be split into sublevels. The simulation maintains an echelon between contiguous sublevels. Other face parameters control the speed of mining, the availability and relative priority of the face.The required production from each crusher/shaft system is specified. The technique of simulating the mining process in order to achieve the required production is described."

Jan 1, 2014

By A. P. L. Kotzé

Modelling and scheduling for Grootegeluk coal mine, situated in the north- western Transvaal, is by means of a series of modular systems. Modelling of the multilayered body, which is part of the Waterberg coalfield, was based on a detailed study of the behaviour of coal and waste qualities and the sub- sequent use of standard geostatistical techniques. A notable improvement on previous methods was attained. Scheduling procedures and systems were developed to model a multibench pit producing coal for several metallurgical plants as well as a power-station. Scheduling was done by producing a series of longitudinal cuts, the cuts being subdivided into increments. By allocating cuts to certain periods, the resulting calculated product tonnages were com- pared with production targets, and by iteration a final scheduling sequence was determined.

Jan 1, 1987

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 C. H. Wyndham, N. B. Strydom

Discussion C. G. Hinds (Member): The climatic chamber at Kloof Gold Mine was built to the design referred to in the paper presented by Professor Wyndham and Dr Strydom. As no suitable underground facilities existed for the acclimatization of labourers at the rate required, mining operations would have been severely restricted had there not been a climatic room timeously built on surface. The climatic room can accommodate 120 labourers per 4-!-hour shift. The standards laid down by the Human Sciences Laboratory were and still are being adhered to as strictly as possible. Through a shortage of European personnel the recommended degree of white supervision could not be adhered to and the use of Bantu assistants with a minimum education of Standard 8 was introduced. This is considered to have met with sufficient success to warrant acceptance as policy. The climatic room was brought into operation on the 1st September, 1967, i.e. two months after stoping at Kloof was commenced. The figures quoted herein therefore pertain to the period between that date and the 31st March, 1969, when the main shaft and the main surface fans were commissioned. The areas worked were sited between 5016 ft and 6 365 ft below surface. Virgin rock temperatures ranged between 92°F and 99°F. Stopes are cleaned by hand lashing. During the 20 months of stoping prior to the commissioning of the main shaft, mining operations at Kloof were effected through the Harvie Watt shaft of the Libanon Gold Mining Company Limited. In this period 10 452 Bantu labourers were acclimatized in the following categories: Experienced workers 7 326 New to the industry 2 086 Re-acclimatized 1 040 It will be noted that during the period, labourers 'new to the industry' averaged 22 per cent of the intake. This percentage fluctuated from time to time and reached 42 per cent. (The present percentage is 60.) The greatest number acclimatized during anyone month occurred in February, 1969 when 1234 Bantu were treated. The greatest number of Bantu acclimatized during any 8-day period was 411. As many as four X 41/2 hour shifts were run in 24 hours. The number of men found to be heat intolerant over the period of 20 months was 33 out of a total 9 412 Bantu. The following tabulation illustrates the history of the build-up of manpower and the climatic conditions under which they worked: The average dip of the reef is 35°. The number of heat stroke and heat exhaustion cases during the period of 20 months under most difficult ventilation conditions was Nil.

Jan 10, 1969

By K. Eckert, A. E. Sommer, S. Heitkam

One highly relevant challenge in flotation is the recovery of fine particles. Due to their low inertia, these particles are mostly pushed aside by rising bubbles. Consequently, they typically exhibit low probability for bubble-particle collision and thus, a poor recovery rate. In this work, the trajectories of fine particles in the vicinity of rising bubbles were investigated. The measurements considered a chain of millimetric bubbles in a rectangular container filled with deionized water. The flow field near the bubbles was measured by tomographic particle image velocimetry (TPIV), employing fluorescent tracer particles of 33μm diameter. Subsequently, trajectories of larger particles and bubble-particle collision events are recorded with 4D particle tracking velocimetry using a high temporal and spatial resolution. The results reproduce the well-known collision of particles on the leading edge of a rising bubble. Additionally, collisions on the tailing edge were observed in cases with a low Stokes number. The TPIV results demonstrate, that the high turbulent kinetic energy in the bubble wake allows particles to divert from the fluid streamlines and collide with the tailing edge of the bubble. The tailing edge collision probability increases with the bubble Reynolds number and decreased particle inertia. Overall, the investigation shows that the collision of fine particles in the bubble wake should be considered for the development of further collision probability models. Furthermore, the importance of turbulence on the fine particle flotation was demonstrated. Keywords: 4D Particle tracking velocimetry (PTV), tomographic particle image velocimetry (TPIV), fine particle flotation, collision probability, bubble-particle interaction, wake induced collision

Jan 1, 2020

By D. W. Dean, J. A. Ryder

"A computer system designed to assist in maintenance scheduling and costing, and in monitoring the performance of equipment, is described. The emphasis is on the information retrieval and implementation aspects of the system.INTRODUCTIONThe cost of the maintenance of equipment can account for a substantial proportion of the total costs of any large industry. These costs are made up of the following elements:(i) capital expenditure,(ii) maintenance labour,(iii) maintenance spares,(iv) maintenance overheads,(v) production losses.Control of these cost elements cannot be achieved without a system which maintains and retrieves the necessary infor¬mation efficiently.The system should provide engineering management with the information necessary to:(i) establish the cost of maintaining items of equipment,(ii)establish the economic life of equipment,(iii) determine breakdown patterns for the establishment of optimum inspection, service and overhaul frequencies,(iv) establish work schedules for those responsible for the maintenance of equipment,(v) establish the optimum maintenance labour complement,(vi) establish the optimum stockholding of maintenance stores items,(vii) improve the performance of equipment,(viii) justify the selection of a particular type and make of equipment,(ix) establish the reasons for any abnormal usage of materials and labour, and to(x)reduce the dependence on the human element for the control of equipment maintenance activities.Many industries have comprehensive and numerous equipment maintenance records but they experience great difficulty in retrieving the required information in the time available and with the labour available. Many industries do not bother to maintain meaningful records, because of this difficulty."

Jan 1, 2014

By D. I. Hoyer, M. F. Dawson

The results obtained from the operation of a batch centrifugal ball mill are reported, together with the development of a model for the behaviour of a particle in free flight within the mill, and the introduction of a cumulative breakage rate function. Schumann and Rosin-Rammler plots show the change in particle-size distribution with time at various configurations of the mill. Graphs showing the rate of production of fines and the rate of breakage of coarse particles are included.

Jan 1, 1982

By J. J. S. de Beer, F. Hunter, A. F. Neethling

SYNOPSIS The paper describes the rib-pillar extraction method now used at Sigma Colliery in the Orange Free State. In this method, access roadways (with a high safety factor) are developed into a block of coal suitable for total extraction; pillars that have a low safety factor are then formed and extracted immediately. The method, together with the current practices of labour management, has resulted in better utilization of the coal resources and capital, increased production and labour productivity, and improved safety.

Jan 1, 1991

By M. J. U. T. Van Wijngaarden

SYNOPSIS The corrosion characteristics of a new steel, 14Cr, which is a modification of the well-known 3CR12, in aqueous sulphate solution were studied through polarization diagrams and a computer analysis based on the polarization¬resistance technique. It was found that the corrosion rate of 14Cr steel is independent of pH for pH values above 6, but, below a pH value of 4, the corrosion rate increases sharply with decreasing pH. In air-saturated solutions of neutral and mildly alkaline pH, the corrosion rate is approximately 60 µm per year. The 14Cr steel shows a twentyfold improvement in corrosion resistance over that of 3CR12 in sulphate solutions at pH 2,0. This is considered to be due to the beneficial effect of its higher chromium and nickel contents.

Jan 1, 1985

By Mr P. W. J. van Rensburg

SOUTH AFRICAN NATIONAL COMMITTEE ON TUNNELLING In 1970, the South African Institution of Civil Engineers, the South African Institute of Mining and Metallurgy, the South African Institute of Mechanical Engineers, and the Geological Society of South Africa held an international conference on tunnelling, known as Tuncon 1970. SUID-AFRIKAANSE NASIONALE TONNELBOUKOMITEE In 1970 het die Suid-Afrikaanse Instituut van Siviele Ingenieurs, die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie, die Suid-Afrikaanse Instituut van Meganiese Ingenieurs en Die Geologiese Vereniging van Suid-Afrika 'n internasionale konferensie in verband met tonnelbou gehou, wat bekend gestaan het as Tonkon 1970.

Jan 5, 1974

On 24th November, 1982, Mr L. W. P. van den Bosch was inducted as the President for 1982/1983 of the Associated Scientific and Technical Societies of South Africa, which represents more than 40 scientific, professional, and technical bodies. Lynne Wilson Pearson van den Bosch was born at Senekal in the Orange Free State on 11th February, 1921. He was educated at the Hoer Volkskool, Heidelberg, and the University of the Witwatersrand, where he obtained the B.sc. degree in mining engineering.

Jan 1, 1983

By H. Zhong, S. Wang, Q. Lin

To improve the flotation performance of chalcopyrite collector, 2-(tert-butoxy)ethyl xanthate (TBEX) and its derivative O-(2-(tert-butoxy)ethyl)-N-ethyl-thionocarbamate (TBEETC) were designed and prepared by the introduction of a 2-(tert-butoxy) ethyl group into xanthate and thionocarbamate. TBEX and TBEETC were both prepared via the one-pot method with superior efficiency, which has significant commercial implications. The micro-flotation tests demonstrated that compared with sodium isobutyl xanthate (SIBX) and O-isopropyl-N-ethyl-thionocarbamate (Z-200), TBEX and TBEETC both possessed better collecting ability and selectivity for chalcopyrite. DFT calculations and XPS were utilised to investigate the flotation mechanism involving TBEX or TBEETC and chalcopyrite. The results demonstrate that although 2-(tert-butoxy) ethyl group does not interact with minerals directly, its introduction reduces the energy of HOMO, so that they can better accept electrons instead of donating electrons which leads to better interaction with copper atoms rather than iron atoms. Keywords: Chalcopyrite, flotation, thionocarbamate, xanthate, synthesis

Jan 1, 2020

By H. Knorre, A. Griffiths, R. Higgins, S. Gos

Hydrogen peroxide is gaining acceptance as a reagent for the treatment of mining effluents containing cyanide. In this paper some of the chemical and environmental aspects of treatment with hydrogen peroxide are discussed, and one way of improving the economics of the process is described. This is known as selective detoxification, which involves the oxidation of the less stable (cyanide) complexes while not affecting the more stable complexes, which contribute very little to the concentration of free cyanide or to the toxicity of the treated water.

Jan 1, 1987

The AK6 kimberlite is situated 25 km south of the Debswana Orapa Mine in Botswana and was discovered by De Beers geologists in 1969 during the follow-up of geophysical targets in the Orapa area. The kimberlite was not extensively pursued at the time as the initial bulk sampling indicated it to be of limited size and low grade, factors largely contributed to by the basalt breccia capping. Completion of high resolution integrated geophysical techniques and drill bulk sampling to depth recovered 97 tons of kimberlite during 2003 and 2004, which led to the increased size and grade estimates. Bulk sampling by Large Diameter Drilling (LDD, 23 inch diameter) commenced in 2005; 13 holes were drilled to a cumulative depth of 3,699 m and 689 carats of diamonds were recovered. In July 2006 the De Beers Mineral Resource Classification Committee classified these Phase I LOO results at a High Inferred level with an average grade of 24 carats per hundred tonnes (cpht) at a bottom cut-off of +1 mm, and a modeled average diamond value of 150 dollars per carat. A second phase of LDO drilling was initiated in 2006, and bulk sampling by trenching commenced in 2007 in order to deliver a resource estimate at indicated level. An Indicated Resource of 11.1 million carats at an average grade of 22 cpht was declared for the deposit mining lease application lodged in 2007.

Jan 1, 2010

By A. W. S. Schumann

A. W. S. Schumann The first reason for todays success lies in the very high standard which was set by our speakers today and I think that we owe a very special vote of thanks to Messrs P. M. C. Wilson, A. A. Oakes, M. J. Deats, A. C. Coetzee, R. E. Burnton and J. G. Ferguson. This, however, cannot account for the fact that there was a tremendous response even before anyone knew who was going to speak or what they were going to speak about. I suggest that the response was enthusiastic because people expected a more informal gathering with a greater opportunity for feedback, for an exchange of views and for questions and answers. The very popularity of the idea has defeated its own ends to some extent. This gathering is too big and many people must have been left with questions unanswered. Possibly one should arrange for a number of meeting places-there are many in the Chamber and the surrounding mining houses-and then have separate meetings in the morning with joint reporting session in the afternoon. Alternatively, we could have a symposium after the colloquium, using Webster's definition of a symposium as as 'a drinking party of merry fellows'. We all know that it is easy to discuss mining into the small hours. Obviously one cannot summarise todays papers and discussions, but I would like to make a few comments on technical matters and after that I would like to speak for a moment about what I see as major trends or tendencies which arise from discussions of this nature. Regarding the question of placing a village on a mine or away from a mine, I would mention that there is quite a body of literature on the adverse sociological effects on the development of children in any community in which the great majority of parents share the same occupation. It is something to be avoided if possible. We discussed the concept of the moving stockpile. If this is proved to be successful, it could save a considerable amount of money for Escom who could then avoid the construction of very large and costly staithes which are now regarded as parts of power stations. One does not see why both a moving stockpile and a staith should be necessary. By the way, speaking of Escom, I see that Mr Bob Scott is here; he has stopped pulling my leg by saying that we sell stone to Escom; perhaps someone has told him that if this is true, it must be the cheapest stone you can buy in this country. My next point relates to the use of epidiascope. It struck me again that this instrument which provides a visual image to accompany your message, can be very effective if it is properly used. These papers speak of a great deal of hard work which went into their preparation, and one really feels that the authors should have taken a few minutes more to prepare their drawings specifically for the epidiascope. There should be nothing on the drawing which is not necessary to illustrate a particular point and there should be nothing on the drawing which is not visible from the back of the hall. In particular, if one cannot read the figures along the sides, then one

By R Linares

For centuries, diamond's superlative properties have earned it a reputation as the 'dream' material for mankind in its search to create advanced applications. Until recently, this dream has been realized only in the use of diamond for gemstones and abrasive applications where several tons of diamonds are now used on an annual basis. The vision of having large, high quality diamond as part of a broad engineering tool-kit for many diverse high tech industries is now becoming a reality however, with the advent of early stage commercial availability of single crystal and poly crystalline CVD diamond.

Jan 1, 2010

By G. Sommer, R. P. Chaix, G. T. W. Ormrod

Recent developments in the instrumentation and automation of uranium-processing plants by G. SOMMER, Ing. (Grad.) (Visitor), G. T. W. ORMROD (Visitor), and R. P. CHAIX, B.Sc. (Visitor) The paper discusses work at the National Institute for Metallurgy on the evaluation of measuring techniques for the automatic control of free acid in leaching. of the ratio of ferric to ferrous ion in leaching, of pH in liquid-liquid extraction. and of uranium in loaded solvent. Commercially available instruments. and the modifications that have been made to adapt them to South African uranium plants, are also described.

By K. Shin

Determining the anisotropy of rocks has in the past been difficult and rarely attempted in engineering practice. Here we have developed a new practical methodology for measuring orthotropic anisotropy that requires only one hollow cylinder specimen to determine the anisotropy of a set, even when the directions of the anisotropic axes are unknown. Autrefois, la détermination de l’anisotropie des roches était difficile et elle a été rarement essayée dans la pratique de l’ingénierie. Voilà c’est nous qui avons mis au point une nouvelle méthodologie pratique pour mesurer le coefficient de conductibilité thermique de l’anisotropie qui exige un seul spécimen du cylindre creux afin de déterminer l’anisotropie d’une série, même si les directions des axes anisotropiques sont inconnues. Früher war die Bestimmung der Anisotropie von Gesteinen ein schwieriges Verfahren, das in der technologischen Praxis nur selten in Angriff genommen wurde. Wir haben hier eine neue praktische Methodik zur Messung der orthotropen Anisotropie entwickelt, bei der nur ein Hohlzylinder an Gesteinsproben benötigt wird, um die Anisotropie einer Reihe von Steinen zu bestimmen, selbst wenn die Richtungen der Anisotropieachsen unbekannt sind.

Jan 1, 2003

By J. F. Morrison, C. H. Wyndham, N. B. Strydom

INTRODUCTION The shovelling of rock in stopes is still a basic and important operation in many gold mines in the removal of gold-bearing rock from the stopes. There is, however, little factual knowledge of the factors which influence the the rates of energy expenditure and work output, and of the way in which variations in these factors, individually or in combination, affect the mechanical efficiency of the mine workers. What for example is the influence of different rates of shovelling, shovel loads and distances of throw? How does stope width and dip of the stope affect the mechanical efficiency of men shovelling rock? Recently a simple physiological test was introduced into the gold mining industry for classifying Bantu recruits into those capable of hard, moderate and light work. If this test is used to select only those Bantu mine workers who are capable of hard work for the task of shovelling rock in stopes then the rate of energy expenditure which could be expected from these men is 1.5 litres/min for the entire period of the shift. With an adequate knowledge of the influence of the various factors which affect the rate of energy expenditure of men shovelling rock in stopes it would be possible to set work standards for Bantu mine workers in stopes. This should be done in terms of the rate of shovelling, the shovel load and the distance of throw for any combination of width of stope, dip of stope, condition of foot wall and grade of rock in such a way that the resultant energy expenditure would be the 'optimum' that could be expected from the men but would be within their capacities for physical work of an endurance nature (that is, 1. 5 litres/min from the 'average' Bantu mine worker). Work standards could thereby be determined for the different stopes of a mine on a sound and systematic basis. In order to supply the information required a study was carried out by the Human Sciences Laboratory in which the work output and energy expenditures (in terms of oxygen consumption in litres/min) were measured on six highly trained Bantu mine workers under the following conditions: (a) rates of shovelling of 3, 4, 5, 6, and 10 shovels per minute. (b) loads of from 9 to 18 lb on the shovel. (c) distances of throw from 8 to 20 ft. (d) stope width of 28 in., 42 in. and 72 in. (e) dip of stopes of 0°, 15° and 30°. (f) rough and smooth footwalls and various grades of rock size. This paper gives the main results of practical importance of this study. Method The experiments were designed and conducted in conjunction with the Work Study Department of one certain underground conditions such as variable stope widths, stope angle, etc., were made available in a mine Surface Training School and suitable subjects were selected from the large number of labourers being put through the training school. Subjects Bantu recruits who had returned to the mine for a new contract and who had previous underground experience on shovelling were considered to be suitable as subjects for the experiments. The particulars of the subjects are given in Table I. TABLE I PHYSICAL CHARACTERISTICS OF SUBJECTS Weight Height Surface area Max O2 capacity Subject (Kg) (cm) (sq meters) (Litre/minute) A 71.5 167.3 1.80 3.5 B 61.5 162.3 1.65 2.8 C 63.0 164.1 1.69 2.4 D 66.5 167.4 1.75 2.8 E 70.2 164.6 1.77 3.0 F 77.8 173.1 1.92 3.8 Training The method of shovelling, accepted by the Work Study Department, was demonstrated to the subjects who then practised the movements with empty shovels, under the supervision of an instructor. After the technique was mastered, the men started shovelling rock and were trained for at least four hours per day to work at the higher shovelling rates. Training was continued for three weeks to enable the subjects to achieve a reasonable degree of physical training and conditioning. Shovelling method In both the kneeling and standing positions the subjects faced the pile of rock, grasped the shovel in the accepted manner and pushed the blade of the shovel into the base of the pile of rock, sliding the blade between the rock and the concrete floor. In the standing position (72 in. wide stope) the back leg assisted in the movement by pushing the knee against the back of the hand holding the shovel handle. In the kneeling position the elbow was tucked into the side of the body so that the muscles of

By Y. Zhan1, T. Moodley, M. A. H. Zahid

Mining operations are under growing pressure to improve safety and efficiency while dealing with aging infrastructure, complex processes, and workforce constraints. Although many sites are equipped with surveillance cameras and control systems, critical events often go unmonitored or under-analysed due to the lack of intelligent interpretation tools. Cameras typically act as passive recorders, requiring manual review by control room operators; a process that is labour-intensive, error-prone, and reactive. Vision AI is emerging as a transformative solution, combining computer vision and artificial intelligence to deliver real-time, actionable insights. This technology has evolved along two key phases: traditional object detection, and more recently, multimodal large language model integration. This paper presents solution architectures, deployment results, and key insights from real-world implementations across underground operations, open-pit truck-shovel operations, and smelter operations, demonstrating how Vision AI is reshaping mining operations to become safer, more efficient, and more intelligent.

Mar 6, 2026