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By Alastair S. Macfarlane

The Mineral Resource that a mining company has access to, represents the majority of the embedded value that exists within the company, as well as the competitive advantage that the company has over its peers. However the real value is only realised once effective mining plans have been put in place, which optimise the extraction of the Resource, and add measurable value to the Company. The concept of Mineral Resource Management has been developed in South Africa, to ensure this optimisation happens in an integrated and quantifiable manner, such that value is added and risk is reduced, resulting in bottom line improvement for the stakeholders of the business. This paper describes the process of Mineral Resource Management, and draws on successes and failures of various companies, to illustrate how it should be implemented, and what measures should be put in place to ensure its success. This requires a fundamental re-appraisal of the way in which mining companies plan and execute their businesses, and focuses attention on real value adding activities and behaviour through the use of Economic Value Added as an appropriate metric by which to measure real value and risk. Specifically, the paper focuses on these aspects as applied to planning models and processes, exploration activity and risk management, to ensure operational and project success.

Jan 1, 2007

By Anthony K. Anyimadu, Chris M. Rule

Froth flotation is the primary mineral processing separation step employed in the beneficiation of PGM ore bodies. Anglo Platinum operates a significant portion of the total installed flotation capacity in the PGM industry, which is installed at 20 operating plants across the Bushveld. PGM flotation has undergone a considerable evolution in both the capacity of flotation cells employed as well as in the circuit design configuration over the past thirty years. Certain of Anglo Platinum?s flotation circuits have been in operation for a relatively long period of time, (in some operations installed equipment dates from the 1960?s) and this allows comparative operating performance between various equipment types and circuits to be evaluated. This paper summarizes some aspects of this experience. Research trends in flotation are continuously monitored to incorporate appropriate findings into existing and future circuit designs. Continuous evaluation and monitoring of flotation performance is undertaken to identify opportunities for increasing flotation efficiencies. Mineralogical and fractional analyses of plant composites and survey samples are analysed to interrogate speciation and association data. This analysis has enabled a better understanding of priorities and opportunities for improved metallurgical performance. These opportunities are divided into three improvement areas: stability, liberation, and fines flotation. The paper discusses these, as well as the circuit design improvements required to take full advantage of the opportunities identified.

Jan 1, 2007

By L. Bloch

Most mine safety initiatives in South Africa are doomed to limited success because of one simple fact: they are a-historical and un-cultural and do not deal with the serious ?legacy issues? that still negatively impact on safety, production, and relationships. We in the SA mining industry continually use imported, foreign safety concepts and systems that will not work fully in a South African context. ?The 4th Wave: Culture-Based Behavioural Safety?, as developed by Lance Bloch, an international award-winning clinical psychologist with 12 years? experience in the mining industry - focused mostly on Platinum - is making waves. He has been very successful in creating people-centred, empowered, high-performance safety cultures wherever he has worked. Not only does the 4th Wave transform the corporate culture of a mine, improving safety and production and building an environment of Ubuntu, but it also uses people?s cultures as a means of winning hearts and minds in the battle for safe production. Powerful relationships are built through engagement at all levels, leading to all being focused on the best needs of the company and its constituents as a whole. The programmes are no less than nation-building - something most necessary in the industry, with the pressures from community, unions, the DMR, and politicians. This presentation will describe and discuss the 4th Wave as an advance on previous safety technology and programmes, as particularly relevant to platinum mining in South Africa today.

Jan 1, 2012

By B. McFadzean, M. Becker, S Geldenhuys, A. Molifie

Mineral hydration is known to result in low flotation recoveries and grades within primary platinum group element ores worldwide. This is because the phyllosilicate minerals derived from hydration reactions of silicate minerals (i) form electrostatic coatings on valuable minerals that in turn hinder collector adsorption, (ii) alter the viscosity of the slurry leading to poor gas dispersion and (iii) decrease the concentrate grade due to naturally-floating gangue. Sodium silicate was investigated because its dispersant, rheology modifying, and depressant properties could prove promising in combating the problems associated with these ore types. Quantitative evaluation by scanning electron microscopy analysis revealed large quantities of serpentine and talc present within the ore sample used in this study, which led to a poor flotation response as indicated by batch flotation tests. Using sodium silicate improved the recoveries and grades at high dosages (>1000 g/t). The zeta potential experiments indicate that improved recoveries are, in part, as a result of the reversal of serpentine surface charge, creating electrostatic repulsion between serpentine and valuable minerals which prevents the coating of valuable minerals by serpentine slimes. Ore dilution and rheology tests indicated that decreased viscosity at high dosages also improved recoveries. Talc micro-flotation tests revealed that the depression of talc occurred at higher sodium silicate dosages, which improved concentrate grade. The processing of nearsurface altered ores is becoming an increasing problem worldwide and the use of sodium silicate proved valuable in mitigating the problems associated with the altered ore investigated in this study. Keywords: Alteration, phyllosilicate slimes, colloidal chemistry

Jan 1, 2020

By M. Dworzanowski

The difference in the magnetic properties of minerals is the basis for magnetic separation. All minerals can be generally classified as ferromagnetic (strongly magnetic), paramagnetic (weakly magnetic) or diamagnetic (non-magnetic). Magnetic separation can be conducted dry or wet. The majority of the applications of wet magnetic separation in the mining industry are based on the wet drum magnetic separator. The wet drum magnetic separator has been in use for over 50 years and its design is based on a rotating drum installed inside a tank. Inside the drum are stationary, permanent magnets arranged in an arc to provide the magnetic field. These magnets can be of the ceramic ferrite type providing a low intensity magnetic field or of the rare earth type providing a high intensity magnetic field.

Jan 1, 2010

Mining executives often have a difficult task determining what the strategic objective of the business should be as this can be impacted by the prevailing market conditions. In addition, they have no mechanism to quantitatively 'test' the impact of this strategic decision on the business and understand the underlying dynamics. During the commodities bull run of 2003 to 2008 the strategic objective may have been to grow the long term value of the business (NPV) through increased tonnage, acquisition and finding new reserves, which all came with an increasing fixed cost base. Now with the financial crisis upon us and the collapse of commodity prices and demand, executives have adjusted their strategies as 'cash is king' and short-term cash flow, in some instances at the expense of long terms value, is the order of the day. For many mining companies, mine closures, reductions in production and cost cutting exercisers are now the focus. In many instances, management do not have an ability to rapidly test different strategic alternatives to 'test' the impact on value, unit costs, reserves and profitability at the operational level and optimize the underlying trade-off variables. Economic modelling of the complete business value chain is a means of linking the operational 'reality' and strategic choices, so that the full impact can be assessed. This paper describes some of the challenges facing mining executives and how economic modelling can be applied to make decision making more rigorous.

Jan 1, 2010

By S. W. Jacobsz, E. P. Kearsley, N. K. Schoeman

A physical modelling approach was adopted to simulate the process of cave mining propagation at various horizontal to vertical stress state ratios, and image data was captured and used to characterize the resulting failure mechanisms. Image processing was integrated into the study to determine minor principal strains in models to identify where critical extensional strains had been exceeded relative to crack propagation. The study exhibited a scale factor magnitude of 119 using a calculated critical extensional strain value of 0.014% for the modelling material used. It was perceived that cave propagation occurred through successive parallel extensional ‘fracture bands’ in all cases, as noticed in models of prior studies, deviating from that described by the Duplancic model. Cracks tended to bisect regions of minor principal strain equal to the critical extensional strain, which suggests ‘fracture banding’ is an acceptable failure mode for brittle, rock-like materials. Moreover, it was found that models with lower horizontal to vertical stress ratios (K ratios) showed a greater degree of vertical development of the caving mechanism (at similar vertical stresses), while the vertical extent of the cave was suppressed in models with higher K ratios. Models subjected to larger vertical stresses experienced slower cave formation in latter time-steps. These models exhibited larger two-dimensional caved perimeters and areas, respectively.

Nov 30, 2022

By E. Pothas, P. R. Jochens, L. B. McRae, D. D. Howat

SYNOPSIS The phase equilibria, viscosities and sulphur capacities of titaniferous slags were determined in the composition range of CaO = 30 to 0 per cent, MgO = 0 to 30 per cent, SiO2 = 19.69 per cent, AI.O. = 13.12 per cent and TiO2 = 37.19 per cent. The phase equilibria were determined by high temperature microscopy, the viscosities were measured using a rotating outer cylinder viscometer and the sulphur capacities were evaluated from the results obtained by equilibrating the slag in a gas stream of CO, CO2 and SO2. The behaviour of these titaniferous slags under reducing conditions was examined. Possible use of the slags for aggregate, or slag-cement, and the possibility of extracting the TiO2 are discussed. CONTENTS INTRODUCTION PHASE EQUILIBRIA VISCOSITIES DISCUSSION OF THE PHASE EQUILlBRIA AND THE VISCOSITY VALUES EFFECT OF REDUCING CONDITIONS SULPHUR CAPACITY DISCUSSION OF THE SULPHUR CAPACITY VALUES POSSIBLE USES CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES INTRODUCTION The latest phase in the exploitation of the mineral wealth of the Bushveld Igneous Complex is the erection of a plant by the Highveld Steel and Vanadium Corporation Limited near Witbank to produce steel and vanadium-rich slag from the titaniferous magnetites occurring in this rock formation. These titaniferous magnetites occur as segregations in the gabbro body and the TiO2 is mainly present within the structure of other constituent minerals but also occurs in smaller amounts as ilmenite and ulvospinel. The vanadium is thought to be present in the iron oxide phase due to isomorphous replacement of the iron. Until very recently, it was feared that the high titania content of these titaniferous magnetites would militate against their value as useful iron ores. However, the design of an integrated plant to produce both steel and vanadium-rich slag, and in which the iron-making process is conducted in submerged arc furnaces instead of in

By T. T. Matuludi

Kleinkopje Colliery has five Wemco drums that were installed and commissioned in 1978. Over the years, there have been remarkable changes in mining and geological conditions at the colliery. First, an increase in the percentage of fines was recorded, which resulted in an uneven split or an imbalance in silo levels between material feeding the cyclone (-12 mm) and Wemco drum (+12 mm) sections respectively. This problem was solved by doing modifications around the banana screens to allow finer material to the drums. The imbalance challenge was then followed by spontaneous combustion that takes place in situ and results in low product yield. The results obtained from efficiency tests indicate that although there is a limit in the percentage of -6 mm material in the feed, Wemco drums are still very efficient and applicable to the current mining conditions. These results also suggest that it is essential to lower the throughput when the drums are treating low yielding coal.

Jan 1, 2010

By M. Kumral, S. Hmoud

Optimising the configuration of infill drill holes is an important step during mineral exploration campaigns. However, this optimisation process encompassing all possible drilling configurations within a mineral deposit is highly combinatorial and hard to solve in a reasonable time. This paper proposes using spatial clustering algorithms to divide the orebody into contiguous zones and target the best zones with infill drilling in order to reduce the size of this optimisation problem. Several clustering algorithms are assessed in a spatial context on hypothetical datasets. This evaluation shows that the hierarchical density-based spatial clustering application with noise (HDBSCAN) algorithm can be used in combination with the uniform manifold approximation and projection (UMAP) dimensionality reduction algorithm to identify contiguous zones in the orebody.

Sep 1, 2021

By K. Basaure, S. Palma, R. L. Castro

"Mud rushes are sudden inflows of fine wet ore within underground mines; they can harm people and equipment as well as cause production delays. Block and panel caving mines are prone to mud rushes in their production levels, with mud flowing from the drawpoints. Different mines have developed methods to control drawpoint conditions and thus perform safe ore extraction. The aim of this study is to develop a decision matrix and apply it to samples from drawpoints for the Diablo Regimiento mine, Codelco, El Teniente Division (Chile). The Abrams’s Cone was used to perform slump tests on mud samples and characterize their consistency by setting the saturation degree and packing. The unconfined strength for different saturation degrees and packing was then evaluated. The results show that conditions for fluid response in slump tests correspond to conditions for low strength in unconfined compression tests. We also found the water content value at which the flowing consistency changes from plastic to soft behaviour according to the slump test classification for each sample. This value varied between 12.2% and 16.9%, depending on the sample tested. Finally, a fluid security factor was defined in order to design an extraction pattern for the samples tested, based on the water content. We conclude that a very densely packed ore is not prone to flowing. The flow properties depend strongly on the specific properties of the ore tested, and consequently a specific criterion should be developed for different types of ore at a particular mine. The criterion developed for Diablo Regimiento ore provides critical water content values from 11% to 15%, depending on the ore type. IntroductionBlock/panel caving has the lowest cost and the highest production rates of all underground methods (Heslop, 2000; Hubert et al., 2000). Good management of the risks is important to ensure the security of personnel and infrastructure. Operational risks for the method include rockbursts, air blasts, and mud rushes (Hubert et al. 2000). A mud rush is defined as a sudden inflow of mud from a drawpoint or other underground opening into the mine (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005). Mud rushes can cause dilution, production delays, and damage to equipment as well as injuries and fatalities. The elements necessary for mud rushes are mud-forming material, disturbances, a discharge point, and water (Butcher, Joughin, and Stacey, 2000). All these elements are present in block/panel caving mines. Mud-forming material comes from ore milled by the caving process; water comes from underground and surface sources. Drawpoints in the production level are discharge points for the mud. Finally, several types of disturbance could trigger the mud rush phenomena: blasting, earthquakes, operation of equipment (Call & Nicholas, Freeport McMoRan, and Hydrologic Consultants, 1998; Jakubec, Clayton, and Guest, 2012), arch collapse above drawbells (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005; Jakubec, Clayton, and Guest, 2012) and ore drawing (Butcher, Joughin, and Stacey, 2000; Butcher, Stacey, and Joughin, 2005; Call & Nicholas, Freeport McMoRan, and Hydrologic Consultants, 1998; Jakubec, Clayton, and Guest, 2012)."

Jan 1, 2017

By M. L. Pududu, B. Ceki, K. Mohajane

This study was aimed at determining the effects of industrial action on profitability in the South African platinum mining sector. We compared companies where employees engaged in industrial action (affected companies) to strike-free companies (competing companies). Industrial action refers to strikes by rockdrillers, as these strikes typically result in the shutdown of production at the mines affected. A t-statistics analysis of significant differences in revenue and earnings of affected and non-affected platinum companies was conducted using data from platinum mining companies listed on the Johannesburg Stock Exchange from 2011 to 2015. Contrary to international studies, which suggest that the spillover effects of industrial action positively affect competing companies, our findings show that profits in the platinum sector decrease significantly during strike periods for both affected and competing companies. The results indicate industrial action is a threat to the profitability of all companies, and that employee demands should be prioritized and negotiated before they result in industrial action. Improved dialogue between management, labour unions, and employees in the platinum mining industry is recommended. The study contributes to the scanty literature on the effect of industrial action on the profitability of mining companies in a developing economy.

Dec 13, 2022

Palladium Alloys. E. M. Savitskii, V. P. Polyakova, M. A. Tylkina. Translated by: R. E. Howard. Published by Primary Services, New York, N.Y. 10012. $24.50. The output of palladium in the U.S.S.R. greatly exceeds the internal usage. The primary purpose of this 200 page volume is therefore to record details of fundamental researches on the properties of this metal with a view to expanding its marketability. Theoretical studies have revealed a number of alloys with great promise in electrical instruments and for the chemical industry. The success of these researches in the U.S.S.R. and in the U.S.A., resulted in the industrial usage of palladium exceeding that of platinum in 1957 and increasing its lead during the next decade. This volume is divided into three parts. Section I covers the mineralogy, extraction and the physical metallurgy of the metal. It records a considerable area where the resistance to corrosion of palladium equals that of platinum. Section II deals with the preparation and the properties of palladium in alloys and contains a comprehensive metallographic treatment of the many binary alloy systems. Section III is devoted to industrial applications. The 460 references which are quoted are mainly from the U.S.S.R. but otherwise have a world-wide coverage. H.B.

By H. M. Dus, D. J. Smith

Resistivity tests indicated that, at temperatures lower than 1450°C, reducing agents alone, as well as burdens consisting of high-carbon ferrochromium and reducing agents, exhibit wide differences in resistivity. These differences are less pronounced at elevated temperatures. The resistivity of a reducing agent and the volume fraction it occupies are important factors controlling the resistivity of burdens of high-carbon ferrochromium. A mathematical model is formulated to describe the dependence of the resistivity of mixtures of conducting and insulating particles on the particle sizes and the volume fraction occupied by the conducting phase. The resistivity of burdens of high-carbon ferrochromium is high if the particle size of the reducing agent is larger than that of the other components of the burden. A number of reducing agents showed small variations in their reactivity towards chromite ore in the solid state. However, with chromite ore in the liquid state, reduction proceeded more rapidly with reducing agents occupying larger volume fractions. During the smelting of manganese ore, high initial rates of reduction were observed for reducing agents that had a high reactivity towards carbon dioxide and a high content of volatile matter, and that occupied a large volume fraction. High liq'uid-state reactivities were observed for reducing agents occupying a large volume fraction and having a Iow degree of graphitization.

Jan 1, 1980

By L. Raaths

This paper outlines the process of improvement utilizing performance monitors and GPS systems on an opencast strip mine. Its primary focus is to maximize coal exposure by draglines and secondly to improve on those processes impacting directly on the dragline operation. The Aquila (DM2/5 system) navigation and monitoring systems were installed on the overburden drills. Their main function is to eliminate manual staking and positioning thereby ensuring a regular pattern being drilled. Holes drilled to planned depth reduce drill metres and it minimizes coal losses and contamination at the coal interfaces. The CAES (Computer Aided Electronic System) will be installed and evaluated on the Caterpillar D11 dozers at Optimum. This system ensures a correct dragline pad elevation through the use of planned elevations and GPS technology to achieve the optimal pad elevations for draglines consistently. The draglines are equipped with a Dragline & Operators Performance Monitor. This monitor allows the operator to control his own performance. It reports on all productivity, method and poor operating techniques. These monitoring systems send critical operational information back to the office. This source data resides in central databases from where it is converted and integrated into management information. To manage an operation means that you as a manager must be able to set objectives and targets and to achieve your goals the activities involved must be measurable.

Sep 1, 2001

By G. R. Marchant, B. K. Loveday

"A mathematical model has been developed for flotation circuit simulation. This model was designed to investigate the effect of varying the circulating loads and to determine whether an improvement in overall efficiency could be gained by a size separation prior to flotation.Model parameters were obtained by regression to plant data. Highly correlated parameters in the model were combined to reduce the number of parameters so that the need for excessive data gathering was eliminated. Mass balance smoothing was used to obtain a consistent data set for regression.The results of the simulation indicate that for the same grade of concentrate, an increase in copper recovery of 0.6 per cent may be Possible by increasing the circulating loads. The results of the simulation also indicated that recleaning of the plus 200-mesh material may be beneficiaL."

Jan 1, 2014

By C. Bergmann, V. Ross

The concept of underground ore processing, in which valuable ore and waste are separated at a coarse particle size to improve the economics of operations and minimise the environmental impact, seems attractive from a sustainability perspective. Perceived benefits of such an operation include energy and cost savings due to a reduced hoisting load, a reduced footprint of surface operations, and using material for backfill that has not been contaminated by process chemicals. Progress in the South African mining industry in this area has however been below expectation, and opportunities for underground processing in deep, narrow reef operations were therefore explored by an Excel-based simulation with sensor-based sorting (SBS) as concentration technology. Various PGM mining scenarios incorporating factors such as the mining rate, depth of operation, and effects of dilution and particle size on the metallurgical efficiency, were compared. Whilst these initial results can be regarded as indicative only, they have shown that the economics of such an operation are driven by selective mining at significantly higher rates than achievable with conventional methods. Also, the cost of preparing, conveying and placing rock backfill will need to be lower than that of hoisting waste and depositing it on a surface dump. Another aspect to be addressed is whether ore sorting machines would be able to operate under harsh conditions underground and what provision would need to be made to ensure their efficient operation. Further investigations should focus on refining costs, incorporating environmental considerations in the modelling of economics and sustainability, and compare greenfields with brownfield scenarios. Keywords: Ore sorting, hoisting, backfill, mining rate, economics simulation

Jan 1, 2020

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 R. A. Plumbridge

I am deeply honoured by your invitation to address your great Institute on this centenary occasion. Mining is a cyclic industry that continuously faces enormous challenges as it wrests the treasures of the earth from an often reluctant mother nature. Throughout the ages, those challenges have demanded great skill from mining men and women, who are required to blend a mixture of robust determination with art and science. Pioneer Miners and Scientists It is not surprising therefore that the first blush of euphoria surrounding the discovery of gold on the Witwatersrand quickly gave way to consternation about the need to increase the metallurgical recovery of gold from the then readily identifiable conglomerate. The rugged pioneer miners had to turn to scientists for their salvation.

Jan 1, 1994

By E. Adlard

This paper sketches an expert system for use underground in pinpointing problem areas in the operation of machines. The system is typically a software 'shell' designed to accommodate a series of 'if-then' rules that are intertinked to systematically search for the cause of the problem. During the search, the system asks a series of questions that have to be answered by the operator and then, when necessary, by an artisan. The rules of the system are generated by a knowledge engineer whose function it is to gather the necessary diagnostic information and prepare it in the required format for the expert system. Much still requires to be done in the development of such systems and in the testing of hardware to withstand the mining environment.

Jan 1, 1990