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By A. V. Z. Brink

This paper describes the development of a monitoring architecture that allows for continuous monitoring of the process of mining, the underground environment, the state of the rockmass and its response to mining. The system is based on an open standard and is non-propriety. It allows for dense sensor arrays in the workplace, wire less communication to the closest power line, and TCP/IP communication to a central server. Continuous monitoring and quantification of the appropriate parameters allows a mine to optimise its mine process; to dynamically access the safety and health risk to people and equipment; and to quantify exposure to potential heath hazards such as dust, gas or noise. Current application examples of continuous monitoring include an application to optimise drilling and blasting thought fragmentation monitoring; an application of wireless sensor network-based monitoring in to provide early detection of potential rockfalls; and a trail to continuously assess the gold grade at the shaft through correlation with radioactivity. It is unlikely that a single monitored parameter will provide adequate knowledge of the assessed risk or even an optimisation approach. Multiple parameters are being combined using cognitive science tools such as Bayesian theory and other statistical methods to improve the accuracy and relevance of, for example, risk quantification. The decision maker is not confronted with massive amounts of raw data but rather with a single knowledge statement such a probability of failure, a human physiological strain index or an optimisation index.

Jan 1, 2008

By David J. Haddock

On Wednesday, 6th July, 1988, 28 members of the Johannesburg Branch of The South African Institute of Mining and Metallurgy and their guests assembled at the Rand Refinery Sports Club, which is situated within the Refinery complex, to hear Dr Daniel Polnow, General Manager of the Refinery, give a very interesting lecture on the Rand Refinery Complex and its activities. Accounting for gold The South African Institute of Mining and Metallurgy will be holding a 3- or 4-day school in the third week of May 1989 on the topic 'Accounting for Gold'.

Jan 1, 1988

By C. Banff, E. C. F. Hamman, J. Venter

Open pit slope stability analyses for large scale instabilities are often carried out using limit equilibrium, finite element or finite difference computer programs. All of these require empirical estimates of rock mass shear strength when calibrated values are not available, which is a common occurrence. A common method of estimating rock mass shear strength is the Hoek-Brown failure criterion, which often over- or underestimates rock mass shear strength when used in limit equilibrium or elastic linearly plastic slope stability analyses, resulting in published alternative estimates for the coefficients of the Hoek-Brown failure criterion. This paper investigates the differences between limit equilibrium and elastic linearly plastic slope stability analysis based on the Hoek-Brown failure criterion. The investigation consisted of a comparison of 3840 RS2 finite element analysis models completed with strain softening, and 216 Slide2 limit equilibrium models. The models were used to evaluate a methodology to determine equivalent limit equilibrium and elastic linearly plastic shear strength parameters that provide the same stable slope angles and instability back break distances as the more representative strain softening stress analysis methods. This paper presents the methodology and compiles the results into design charts and equations for equivalent limit equilibrium Mohr-Coulomb shear strength parameters, that simplify calibration against actual case studies. The results compare well with older empirical shear strength estimates, however, a detailed calibration of the results against case studies will need to be carried out. The analysis also did not consider pore pressure effects; this is left for future publication.

Sep 1, 2025

By D. Rankin, H. J. Stucke, W. K. B. Loftus

SYNOPSIS Planning for the Finsch opencast mine is described with particular reference to the proposed stages of mining, the method used to determine the limits of surface waste rock stripping and the derivation of the waste rock mining rate. Actual mining practice is described and the possibility of installing a skipway into the open mine at a later date is discussed. In addition, the waste dumping policy is referred to: this includes the cutting of slots through the hill on the west side of the pipe to increase tramming speeds. The crushing, washing and recovery sections of the treatment plant are described together with the various changes being made to the circuit. The most important of these are the installation of X-ray sorters for the final recovery of + 7 mesh diamonds, and the vibrating grease belt for the recovery of - 7 mesh diamonds. INTRODUCTION The Finsch Mine, a subsidiary of De Beers Consolidated Mines, Limited, is situated approximately 90 miles west of Kimberley, and some two miles from the village of Lime Acres, in the Northern Cape. Lime Acres is a company village shared with the Northern Lime Company which operates a limestone quarry and works near the township. The mine is near the southern end of a well mineralized belt producing limestone, asbestos, diamonds, manganese and iron ore, and the whole area has developed rapidly in the last 20 years. Power for mining operations is drawn from the Electricity Supply Commission. The mine is conveniently close to the main Kimberley-Postmasburg railway line. Water is drawn from the Vaal River through a 57 mile State-owned pipeline at present temporarily operated by mine staff. DISCOVERY AND PROSPECTING OPERATIONS The diamondiferous orebody is situated on the farm Brits, which is State-owned ground that has been leased to the Company for the period of mining operations. There are indications of interest in the area by prospectors (Richter, de Bruin and others) over a period of some 30 years and the discovery would possibly have been made years earlier but for a law preventing prospecting for precious stones on State-owned land. Although the pipe formed a clear depression on the hill where it was situated, it was overlain by some 5 to 40 ft of banded ironstone rubble which was washed into the depression from the hillside above the pipe and obscured the deposit. In 1958, Mr Allister Thornton Fincham applied for, and was granted, the right to prospect for base minerals on the farm Brits. Asbestos is known to occur in the area and, initially, was Mr Fincham's primary interest. However, during the prospecting operations, garnets were discovered and it was realised that diamonds might be present. In 1960, when the Precious Stones Amendment Act was passed, a company

By N. Naude, L. S. Leal Filho, M. P. Tshazi

In this paper, the authors performed experiments in the Denver and Leeds laboratory flotation devices at the University of Pretoria at various particle sizes to evaluate the performance of the devices. Quartz was used in a single mineral system at discrete sizes fractions, -25 μm, +25- 45 μm, +45-75 μm, and +75-106 μm. Hydrodynamic analysis, based on dimensionless power and Reynolds numbers, indicated that the Leeds cell required higher power input to achieve comparable flow conditions. Specifically, the Leeds cell exhibited an average power number of 1.03, whereas the Denver cell averaged 0.77 within the same impeller speed range of 1000 rpm–1500 rpm. For comparative flotation performance, impeller speeds were calibrated, resulting in operating speeds of 1200 rpm for the Denver cell and 1400 rpm for the Leeds cell. The cells performed similarly at two coarser-sized fractions. However, some deviations were observed in the finer particle size range. The -25 μm (fine) fraction initially achieved a recovery of only 15%. An additional reagent dosage was required to enhance the recovery of this fraction significantly. These findings highlighted the influence of particle size on flotation recovery. For all experiments, the Denver laboratory flotation cell outperformed (defined by higher recovery) the Leeds device, while still operating at a lower impeller speed. This advantage can be attributed to its impeller-stator design and air dispersion features, effectively overcoming slurry resistance and resulting in superior flotation performance compared to the Leeds cell.

May 27, 2025

By S. Asokan, Ch. V. G. K. Murty, R. Upadhyay

Zircon (ZrSiO4) is the most frequently found zirconium ore occurring in heavy mineral sands, from which it is extracted as a co-product in the production of ilmenite and rutile. Estimated world reserves of zircon are 124 million tonnes, highest in Australia (around 56 million tonnes), followed by Mozambique (15 million tonnes), India (12.6 million tonnes) and South Africa (12million tonnes). Zircon finds its application in ceramics (54%) and refractory industries (14%), which account for 68% of zircon?s total world consumption of 1.20 million tonnes. The rest (32%) is consumed in foundry, TV glass, zirconia chemicals and other applications. It is a long recognized feature of the zircon industry that supply is totally dependent upon the concurrent production of titanium minerals. But in recent years, several new developments such as the discovery of zircon-rich mineral sands in Australia, the continuing trend of higher prices of zircon and increase in trade of lower quality zircon have changed the scenario. These factors have prompted more intensive efforts to increase the recovery of zircon, particularly in the process for separating zircon from alumino-silicate minerals. Tata Steel?s proposed heavy mineral sands deposit contains on an average 10% heavy mineral content and 15% slimes of the size below 63 micron. Mineral assemblages of the resource contain65?70% ilmenite, 4?6% rutile, 4% zircon, 16% sillimanite and other minor minerals. Wide size range and tenacious iron oxide coating are the inherent characteristics of this deposit. High concentration of sillimanite among the non-magnetic heavy minerals and heavy surface coatings on the minerals are challenges for high recoveries and production of premium grade zircon. This paper outlines various process steps that were taken at pilot plant stage to produce zircon of premium grade and subsequently develop the appropriate flow-sheet.

Jan 1, 2007

By M. Nakamura, T. Akamatsu

Embankment dams are often constructed on soft rock foundations in Japan, so it is important to precisely predict deformation of the foundations due to fill placement at the design stage. In order to accurately evaluate the settlement and the strain of the rock foundation surface during construction, the influence of the scattering of the deformability of foundations on the deformation behaviour should be investigated. In this paper, a method of evaluating the settlement and the strain of the rock foundation surface during construction was studied with stochastic deformation analysis considering the scattering of the deformability of the dam foundation. Based on the analytical results, a dam foundation design using the deterministic method considering the scattering of its deformability was discussed. Da in Japan Uferdämme of auf weichen Felsfundamenten gebaut werden, ist es wichtig, die Verformung der Fundamente auf Grund der Platzierung der Aufschüttungen bereits in der Planungsphase genau vorherzusagen. Im Zusammenhang mit einer genauen Beurteilung der Senkung sowie der Belastung der Felsfundamentoberfläche während der Bauarbeiten sollte auch der Einfluss der Streuung der Verformbarkeit der Fundamente auf das Verformverhalten untersucht werden. In der vorliegenden Studie wurde die Bewertungsmethode zur der Senkung sowie der Belastung der Felsfundamentoberfläche während der Bauarbeiten mit Hilfe von Wahrscheinlichkeitsanalysen der Verformung unter besonderer Berücksichtigung der Streuung der Verformbarkeit der Dammfundamente untersucht. An Hand dieser analystischen Ergebnisse wurde das Design der Dammfundamente dann enthusiastisch mittels deterministischer Methoden hinsichtlich der Streuung der Verformbarkeit diskutiert. Comme les barrages en remblai sont souvent construits sur des fondations rocheuses tendres au Japon, il est essentiel de prévoir précisément les déformations des fondations causées par la mise en place du remblayage durant la phase de conception. Afin d’évaluer avec exactitude le tassement et la déformation de la surface du rocher de fondation durant la construction, l’effet de la dispersion de la déformabilité des fondations sur le comportement de déformation doit être étudié. Dans cette étude, l’auteur a étudié la méthode d’évaluation du tassement et de la déformation de la surface du rocher de fondation durant la construction en procédant à une analyse aléatoire/stochastique de la déformation et en prenant en considération la dispersion de la déformation des fondations du barrage. En se basant sur les résultats de l’analyse, la conception des fondations de barrage avec la méthode déterministe considérant la dispersion de sa déformabilité a été activement discutée.

Jan 1, 2003

By P. R. Jochens, D. D. Howat, C. W. Wolhuter

Prof D. D. Howat (Member): I am a man with a grievance this afternoon. The other authors of the paper entered into a conspiracy to ensure that I presented the paper, and finally even had the audacity to say that this was the least that could be expected from me as I had done so little of the other work. Looking at the distinguished audience here that includes some figures who have forgotten more about cement that some of us have ever learned, I realise how right the other authors were. I feel very much cast in the role of the fool who was pushed in where angels fear to tread. I hesitate to say, Sir, that I would not use the word angels in any definition of the authors of this paper. In presenting the paper, may I try to put forward a few simple points about cement that are probably as little known to the majority of the audience as they were to me-at least until very recently. Concrete, made by mixing Portland cement, sand, crushed rock and water is the most widely used constructional material in the world. Generally the production of actual Portland Cement is about two-thirds that of steel and by the time this is formed into concrete the total is about five times the world tonnage of steel produced. A very rough approximation suggests that world consumption of concrete is about one ton per person per annum. Apart from fresh water mankind consumes no other material in such quantities. What mankind originally required was a mortar to be used for joining blocks of stone or bricks. Such mortar was originally made from limestone burned in a kiln and then mixed with water. Production of mortar of this type began over 5,000 years ago. Some samples from pyramids in Egypt have shown this mortar to be in good condition although over 4,500 years old. The progress of technological development was very slow until 1824 when an English bricklayer, Joseph Aspidin, patented a new mortar material which he made by burning limestone and clay together in his kitchen stove. Aspdin called his product 'Portland Cement' because, in colour, it resembled a well-known building stone quarried in the Isle of Portland on the south coast of England. Aspid's same types of raw materials are used today in modern cement production and the product is still referred to as Portland cement. A lime-containing material such as chalk or shell and a clay-type material such as shale, slate or clay itself, are mixed in the required proportions, ground and fed to a kiln where the minimum burning temperature is about 1,500°C. The raw materials react to form hard chunks of a material known as 'clinker'. About 5 per cent of gypsum is added to the clinker and the mixture is then ground to a very fine powder, the function of the gypsum being to control the rate of setting of the concrete. The key oxides in cement production are lime, silica, alumina and iron oxide. The possible reactions occurring during and the products of the burning process are shown in Table I.

Jan 12, 1968

By H. M. Friede, R. H. Steel

Tin mining and smelting in the Transvaal during the Iron Age by H. M. FRIEDE*. Ph.D. and R. H. STEEL* (Visitors) This paper reviews the historical, archaeological, and metallurgical evidence on Iron Age tin mining and tin smelting in Southern Africa. The results of the analysis of twenty samples of tin ore, tin slag, and tin ingots found associated with Iron Age materials in the Transvaal (mostly in the Rooiberg area) are reported and discussed. The types of ingots preserved in local collections are described. A small experimental tin-smelting furnace was constructed and worked according to traditional African Iron Age technology. Qualitative and quantitative results of this experiment are reported.

Jan 7, 1976

By R. Lechuti-Tlhalerwa

"Geometallurgy aims to improve mining project value by predicting the impact that ore and waste characteristics will have on mining and metallurgical processes. This requires integration of rich spatial models of orebody characteristics with validated process response models. These models have, until recently, been constrained by the spatial coverage and representativity of relevant data and the ability to validate predictions made.The revolution in the diversity and volume of data and computational power that is now becoming available for integrated geoscientific modelling of orebodies, and stochastic simulation of mining and mineral processes is accelerating. By embracing emergent integrated data analysis and simulation techniques, geoscientists and engineers can lead a transformation in the way the mining value chain, from orebody to recovery, can be conceived, evaluated, and operated by using the geometallurgical paradigm.This paper describes a methodology that is applied to an existing diamond operation. Analysis of spatial and process data is used to build an integrated geometallurgical value chain model (IGVCM). This IGVCM is used to generate geometallurgical options and evaluate their potential outcomes. The model facilitates the use of flexible, highly configurable, and potentially automated intelligent approaches to evaluate mining and mineral process configuration, and results in more robust design outcomes. The approach described here, and its successful implementation has potential to deliver step-changes in value. IntroductionGeometallurgy aims to identify treatability risks – and opportunities – that arise from the interaction of orebody characteristics with mining and treatment. Improved understanding of the rock/process relationships allows project planners and production teams to predict performance, identify potential shortfalls, and thus enable the proactive creation and evaluation of strategies to mitigate these risks. These advanced insights also create opportunities for continually improving operational performance through dynamically adapting and improving the process response to the changing properties of the ore (Figure 1)."

Apr 1, 2019

By B. P. Watson

The Bushveld platinum group metal deposits in South Africa are the largest in the world. These deposits occur as two distinct stratiform tabular ore bodies and strike for many hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2300 m. The mining method is a variation of planar open stoping. Crush pillars are widely used to support the open stopes. These pillars are designed to fail and the residual strength provides the required support resistance to stabilize the stoping excavations. This paper describes the in situ measurement, of stress within a Merensky pillar from Impala Platinum. These measurements were used to derive a stress-strain curve that includes pre and post failure behaviour. 2D FLAC modelling, with strain softening, was done to investigate how damage expands into the hanging- and/or footwall. Although the so-called ?squat? effect is always present, the modelling suggests that it does not dominate the pillar system behaviour at larger width to height ratios. Punching of the pillar into the hanging- and/or footwall increasingly controls the pillar system behaviour with larger width to height ratios. The paper investigates the behaviour of a system that incorporates the immediate hanging- and footwall, as well as the pillar itself.

Jan 1, 2009

By I. B. Fernandes, M. A. Reuter, A. Abadias Llamas

Metallurgical simulation and evaluation of the resource efficiency of whole production processes are of key importance for impact assessment, in terms of environment and resources. Exergy is a measure of resource consumption, taking into account energy, raw materials, water, and chemicals; which allows for the evaluation of different technologies to find the most resource efficient and environmentally friendly process. This paper compares the sustainability for production of rare earth magnets from primary and secondary resources through an exergetic evaluation of the production process, in addition to traditional life cycle assessment (LCA). The methodology makes use of simulation tools for tracking material flow and resources used, based on thermodynamic laws, from ore exploitation to magnet production and recycling. It highlights areas with the greatest potential for improvements in terms of resource consumption and environmental impact generation, having a thermodynamic-validated flowsheet for primary and secondary production of NdFeB magnets, present in several low-carbon technologies, such as wind turbines, electric vehicles, and cooling systems. It demonstrates the minimum exergy destruction for magnet production, through an irreversibility breakdown chart, showing where irreversible material and energy losses occur. Results show that CO2-equivalent emissions for producing NdFeB permanent magnets from primary resources could be twice as high when compared to magnets produced from recycling technologies. The theoretical maximum exergetic efficiency for primary production is 57.61%, whereas for permanent magnets produced from secondary resources, the exergetic efficiency reaches up to 82.89%. Two magnet recycling technologies were evaluated, i.e. in acidic medium and via hydrogen decrepitation, and it was observed that their exergetic efficiency and environmental impact performed better than production from primary resources. Keywords: Resource efficiency, exergy analysis, permanent magnet recycling, process simulation, system design

Jan 1, 2020

By I. J. Geldenhuys

South Africa’s mining and metals industries have an illustrious history dating back to the Late Iron Age. We live in a complex and data-intensive world that has already fundamentally changed how we work and live. The outbreak of the global COVID-19 pandemic in 2020 resulted in immeasurable suffering worldwide, but the crisis also accelerated many technological developments and altered the way we think about, and experience, technology and work. Problem-solving requires new and rapidly changing skills to manage the data tsunami. Whether at the rock face or on the processing plant, the fundamentals have not changed, although how we interact with minerals and their properties has changed dramatically. Sustainable processing and design are non-negotiable if we genuinely want to achieve the aim of the cradle-to-cradle principle. As we venture forth, what can scientists, engineers, technologists, and mathematicians learn from history? History is data presented in a context; sometimes, the context is also important. We exist in an age of data, with most of the world’s data created in only the past two years. History can enhance our understanding of the present and enhance our future outcomes. Lessons from history can help provide insights into making ethical and sustainable choices related to technology or engineering in the mining and metallurgical industry. Shifting the perspective of mining and metallurgy professionals from a narrow focus on complex technical solutions towards a broader context for problem-solving and designs that includes the entire ecosystem is crucial. In other words, using or reflecting on historical process development is, at its core, systems thinking.

Sep 1, 2021

By J. P. G. Pretorius, T. C. Partridge

The analysis of angular atypicality of lineaments as an aid to mineral exploration by J. P. G. PRETORI USc, M.Sc. (Pret.) (Visitor) and T. C. PARTRIDGE, Ph.D. (Natal) (Visitor) In an exploration project, data pertaining to 84000 lineaments in an area of 25 000 km2 were recorded. The total length of lineaments in intervals of one degree was determined. Angular intervals with Iow length densities were regarded as atypical. The proportion (by length) of lineaments with such atypical orientation was calculated for 5 km X 5 km grid squares. This index of angular atypicality was contoured and, used in conjunction with conventional photogeological techniques, contributed in a large measure to the success of the investigation.

Jan 5, 1974

By B. Mbuya, A. F. Mulaba-Bafubianda, J. M. Mvita

The paper explains the main effects of input leaching parameters, such as addition of a reducing agent, acidity, agitation, temperature, and leaching system potential, in relation to observed and predicted yields of sought-after cobalt. An artificial neural network coupled with graphical probability networks was developed wherein the abovementioned input parameters were used to predict the percentage of dissolved cobalt. Furthermore, similarities and differences between the Bayesian and neural network approaches in terms of their key outcomes are compared with respect to study of the dissolution of cobalt in sulfuric acid. Key results indicate that there is a need to use neural network results to predict conditions for dissolution of cobalt, while using Bayesian network to explain inferences about conditions of the input parameters, thereby achieving realistic predictions.

Jan 1, 2023

The 96th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room of the Transvaal Automobile Club in Johannesburg on Wednesday, 11th August, 1993. OBITUARIES The President announced the deaths of the following members of the Institute during the past year. Life Fellow E.F. Laschinger. Other Members R.K. Boright, J.S. Jacobi, R.D. Power, J.H. Cannon, C.J. du Plooy, L.B. Mcrae, C.P. Rossouw, A.L. Sillars, A.W. Heugh, R.K. Briggs, P.J. Stark, and C.S. Stott. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, all rose and observed a moment of silence.

Jan 1, 1993

Prof C T O'Connor holds the degrees of BSc, BSc Hons, University of Cape Town (UCT), where he started his academic Lecturer in the Department of Physical Chemistry in 1976. Mr P Smith, educated in England and the former Southern Rhodesia, joined Gold Fields of South Africa in 1966 as a Metallurgical Learner Official. After obtaining a BSc Eng at the University of the Witwatersrand in 1972, he returned to Gold Fields. Mr P D K Robinson was born in Zimbabwe, and was educated at Dale College in Kingwilliamstown, matriculating in 1952. He holds a Mine Surveyor's Certificate obtained in 1961) and a Mine Manager's Certificate (obtained in 1966), as well as an EDP from the University of the Witwatersrand.

Jan 1, 1991

OFS Branch Proceedings of the Annual General Meeting ofthe O.F.S. Branch on Wednesday, 31st July, 1974. The Annual General Meeting of the Branch was held at the Western Holdings Limited Canteen on Wednesday, 31st July, 1974 at 7.30 p.m. Mr E. T. Wilson (Chairman) was in the Chair. There were also present: Papers of interest The following papers may be of interest to members. Education fund The Institute has recently brought into being a Fund to finance various educational projects.

Jan 5, 1974

By H. Sasao, Y. Obara, A. Hirata

In the upper part of the planned location of the portal of a highway tunnel, there was a steep rock cliff with several unstable rock blocks. It seemed that the risk of those rock blocks to fall was very high. The cut-out to stabilize the rock cliff was monitored with various measuring instruments to prevent the sudden fall of the rock blocks. This paper discusses the measurement of acoustic emission and interpretation of its result during excavation of the rock cliff. We calculated displacements by integrating the accelerogram twice in terms of time, and demonstrated that slight displacements can be calculated from the measured AEs. Dans la partie supérieure de l’emplacement prévu pour le portail d’un tunnel autoroutier, il y avait un escarpement rocheux raide avec plusieurs blocs rocheux instables. Le risque de chute de ces blocs semblait très élevé. Lors de la coupe pour stabiliser l’escarpement rocheux, le suivi a été effectué avec différents instruments de mesure pour éviter la chute brutale des blocs rocheux. Cette thèse présente les mesures d’émission acoustique (EA) et l’interprétation de leurs résultats pendant l’excavation de l’escarpement rocheux. Nous avons calculé des déplacements en intégrant l’accélérogramme deux fois par rapport au temps, et montré que de petits déplacements sont calculables à partir des EA mesurées. Im oberen Teil des geplanten Ortes des Stollenmundes eines Autobahntunnels gab es einen steilen Felsen mit mehreren instabilen Felsenblöcken. Die Gefahr schien sehr groß zu sein, dass diese Felsenblöcke einstürzen können. Beim Abbau um die Stabilisierung des Felsens wurde das Monitoring mit verschiedenen Messinstrumenten zusammengestellt, um den plötzlichen Verfall der Felsenblöcke zu verhindern. Das vorliegende Papier diskutiert die Akustische Emission und die Auslegung deren Ergebnisse während des Abbaus des Felsens. Wir berechneten die Verschiebungen durch zweimalige Integrierung der Accelerogrammen in Bezug auf die Zeit. Die dargestellten kleinen Verschiebungen können aus den gemessten akustischen Emissionen berechnet werden.

Jan 1, 2003

By Dr Peter Laxen

Dr Peter Laxen, the Mintek Consultant on gold and uranium, has won the 1982 award of the Percy Fox Foundation. The presentation was made by the Minster of Finance, Mr Owen Horwood, at a banquet on 6 March.

Jan 1, 1982