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By J. -M. Chautru

A geostatistical simulation of a typical mining site for polymetallic nodules in the North Pacific Ocean is presented. This is the first stage in the design of an industrial mining system. Two variables which have a major effect on the orebody's economic potential are considered, namely: the maximum slope of the ground inside a mining block of 50 x 100 m; and the average quantity of nodules on the same support. Two geostatistical problems have emerged in this study. The first is due to the lack of a change of support model for the maximum of a variable. A provisional solution, considering an experimentally accessible 'equivalent' support, is proposed. The second is due to a non-linear link between the two variables. To be able to take this into account in the simulation, we propose a new method based on the decomposition: X = E(X/Y) + Residue (X). Satisfactory results were obtained with this approach.

Jan 1, 1987

By Q. G. Reynolds

The dual-electrode DC arc furnace, an alternative design using an anode and cathode electrode instead of a hearth anode, was studied at small scale using computational modelling methods. Particular attention was paid to the effect of two key design variables, the arc length and the electrode separation, on the furnace behaviour. It was found that reducing the arc length to brush arc conditions was a valid means of overcoming several of the limitations of the dual-electrode design, namely high voltages and arc deflection.

Jan 1, 2012

By M. Solomon

During the course of 2011 the nationalization of mines emerged as one of the most contentious and emotive political issues under review. Some four years after the African National Congress electoral conference held in Polokwane, which had led to a change of leadership within the country's ruling party, elements within the ruling party's youth league, which had been virulently supportive of the change in leadership, turned on the incumbent President, using the mining question as its rallying call. At issue was the expressed perception that mining has, since the country's democratization, not delivered the anticipated benefits to the population as a whole, continues to be the preserve of the capitalist element of the South African community, and is therefore in need of radical reform. Aspersions were made that transformation within the industry had failed dismally and that mining companies had not delivered against their commitments to the Mining Charter and social and labour plans. The debate became extremely vocal and heated, evoked dramatic and emotive opinions, and vigorous skirmishes on the matter were fought in the media over much of 2011 and into 2012.

Jan 1, 2013

By J. P. Beukes

South Africa holds approximately three-quarters of the world?s viable chromite ore resources and dominates the global production of ferrochrome. Albeit completely unintended, small amounts of Cr(VI) are formed during ferrochrome production. Certain Cr(VI)species are regarded as carcinogenic, hence making the treatment of some ferrochrome waste materials necessary. In this paper, the Cr(VI) treatment strategies currently employed by the South African ferrochrome producers are investigated by means of a literature review and a questionnaire survey. From the discussion, it is evident that various treatment strategies are available to deal with Cr(VI)-containing waste in the ferrochrome industry. However, by far the most commonly applied treatment strategy remains the aqueous reduction of Cr(VI) with ferrous iron. The advantages and the correct application of this strategy, together with the disadvantages and pitfalls, are argued. Innovative improvements on historic practices are also discussed

Jan 1, 2012

By M. Kilfoil

Many minerals processing operations result in crushed rock being mixed with a liquid. Sometimes, the rock particles have to be dried before the next process begins and there may be a considerable distance between the equipment carrying out these processes. Bateman Engineered Technologies (BET) developed, patented and commercialized a method of simultaneous pneumatic conveying and drying. A joint project to assist with optimizing the process is under-way. Part of it is a numerical simulation of the process. The simulation is done using a dedicated program written in MATLAB, (commercial software which is widely used in engineering). It accounts for heat and mass transfer as well as particle transport. The main part of the program consists of a loop containing a series of equations which are evaluated sequentially. During any particular iteration, the properties are changed one at a time. Since the properties are changing relatively slowly, this method gives good results. The outputs of the simulation are consistent with the operational experience of BET’s engineers. The output is very comprehensive and all numerical. Since the program is currently being used for research purposes, flexibility is very important. Thus the output is converted into a spreadsheet file. Variations in the output quantities are displayed graphically using MS Excel. Some simulation could have been done using computational fluid dynamics (CFD) software. The advantages and disadvantages (technical, financial and skills requirements) of the two approaches for this particular type of simulation are compared briefly. Keywords: Pneumatic conveying, Heat and mass transfer, Computer model

Jan 1, 2003

By C. Kirmanli

The purpose of this paper is to develop an expert system for hydraulic excavator and truck selection in surface mining. Hydraulic excavators and trucks are finding increasing applications in mining operations. Hydraulic excavators are extensively used especially when bringing electricity to rural areas is difficult and for small-scale mining. This paper describes an expert system, which selects the optimum hydraulic excavator truck configuration such that unit production cost is minimized and technical constraints such as geological, geotechnical and mining constraints are satisfied. The system has four modules: user interface, rules and an methods, databases and output module. The expert system in this study is developed within KappaPC shell. It supports object-orientated technology for the MS Windows environment. The software provides a very useful tool to practitioners, saving time and cost. Equipment selection is a recurring and expensive problem of mine planning and often involves interdisciplinary experts from different fields. It is very difficult and expensive to bring together all these experts. The capabilities of the expert system developed are illustrated in the paper. The software overcomes the difficulties of selecting the proper equipment for surface mining operations, which is very important, and results in substantial savings. Equipment databases for hydraulic excavators with 15-59 yd3 capacities and trucks with 35-360 tons are constructed and these databases are used to select the proper configuration. A case study is carried out for Soma Surface Coal mines in Turkey. Keywords: surface mining, expert systems, equipment selection, hydraulic excavators, diggability

Jan 1, 2009

By T. Tholana, P. N. Neingo

"A mineral resource constitutes the principal underlying asset of a mining company, and must be exploited and managed in such a way that maximum value is derived from it. Various asset management frameworks applicable to physical assets are available. This paper focuses on the extension of an asset management approach, particularly the Publicly Available Specifications (PAS) 55 asset management framework and the International Organization for Standardization (ISO) 55000 series of standards, to mineral assets. It is concluded that PAS 55 and the ISO 55000 series of standards can be extended to manage mineral assets, resulting in an integrated approach to sustainably optimize value from the company’s mineral assets. The benefits include improved returns on mineral assets, maximum mineral asset utilization, creation of an organizational culture focused on quality and continuous improvement, and assurance to stakeholders that the mineral assets are being efficiently managed over their entire life-cycle. In the context of this paper, a ‘mineral resource’ refers to both Resources and/or Reserves as classified by the SAMREC Code. IntroductionMining involves the extraction of valuable mineral resources from the Earth’s crust. A mineral resource is unique among natural resources in the sense that it is a wasting asset, which means that its value depreciates continuously with extraction. In addition, it is often impaired from time to time as commodity price changes (Macfarlane, 2011a). Since a mineral resource is a wasting asset there is a single opportunity available to optimize value from its extraction. Mine planning involves identifying a strategy to exploit the mineral resource in a way that maximizes value at an acceptable risk level throughout the life of mine (LOM). This optimum extraction strategy changes as economic conditions change, particularly commodity prices, as well as with improvements in orebody knowledge as mining progresses. It is the mineral deposit that competitively distinguishes two different mines and dictates the location of a mine; hence the adage ‘the orebody dictates’. Therefore, a mineral resource is the primary tangible asset possessed by mining companies and must be managed in such a manner that maximizes its value at an acceptable risk level (Macfarlane, 2011a)."

Jan 1, 2016

By W. Newcomen, D. Brox

The assessment of the stability performance of open pit highwalls has traditionally been based on consideration of surface movement rates. Although generally accepted in industry, this approach presents challenges for establishing appropriate threshold values to allow for safe mining operations and does not address the issue of total strain. Surface movement monitoring data from a limited number of open pit mining operations in North and South America has been evaluated in terms of highwall strain, rock mass quality and inferred mechanism of instability. Threshold strain levels for key stages of highwall stability proposed from previous work has been reviewed and are endorsed based on evaluation of additional data. An empirical highwall strain criteria for the assessment of highwall stability performance is postulated based on relatively consistent trends in highwall strain data. L’évaluation du niveau de stabilité des hauts murs de carrières a traditionnellement été basée sur les taux de mouvements de surfaces. Bien que cette approche soit généralement acceptée à travers l’industrie, elle présente des défis pour la définition de seuils appropriés concernant la sécurité des opérations minières et n’adresse pas la notion de déformations totales. Des données de mouvements de surface provenant d’un nombre limité d’opérations minières à ciel ouvert d’Amérique du Nord et du Sud ont été évaluées en terme de déformation des hauts murs, de qualité de la masse rocheuse et des mécanismes inférés d’instabilité. Des seuils de déformation pour différentes phases clefs de stabilité de hauts murs ont été revus et sont endossés, basé sur l'évaluation de donnés additionnelles. Un critère de déformation empirique pour l’évaluation de la stabilité des hauts murs est postulé, basé sur des tendances relativement consistantes de données de déformations de hauts murs. Die Beurteilung der Stabilität von hohen Felsböschungen basiert traditionellerweise von Oberflächenbewegungen. Obwohl dieses Verfahren im Allgemeinen akzeptiert wird, stellt es jedoch gewisse Probleme für die Festlegung von Grenzwerten für die Sicherheit dar. Die totalen Dehnungen werden bei dieser Betrachtungsweise vernachlässigt. Eine beschränkte Anzahl von Oberflächenbewegungs Daten von Bergbauwerke in Nord- und Südamerika sind in Bezug auf die Dehnungen von hohen Felsböschungen, Felsqualität und davon abgeleiteten Bruchmechanismen untersucht worden. Grenzwerte für die Belastung von hohen Felsböschungen während den massgebenden Bauetappen aus bisherigen Projekten sind begutachtet und durch zusätzliche Untersuchungen bestätigt worden. Gestützt auf relativ konsitenten Trends, ist hier ein empirisches Verfahren der Dehnungen in hohen Felsböschungen zur Beurteilung der Stabilität vorgestellt.

Jan 1, 2003

By S. O. Choi, C. Park, C. Sunwoo

Two methods of stress measurements have been executed on the surface and underground to con-struct an oil storage cavern using hydro-fracturing and overcoring method. The first measurement has been performed to make a design of the caverns before excavating and the second to confirm the stress state during excavation. Six measurements have been carried out in the hydro-fracturing test at the depths between –17.8 and 54.5m from the sea level and a single measurement in the overcoring test in a single borehole at the depth of –21m from the sea level. The ratios of the maximum horizontal to vertical stress measured using hydro-fracturing and overcoring method are 2.95 and 3.1, respectively. Also, the orientations of the maximum horizontal stress are N53E and N58E. These measurements show that both methods give almost same results and significant horizontal stresses are acting on this cavern. Deux méthodes de mesure de contrainte ont étè exécutées sur la surface de terrain et sous la terre pour construire une cavité de stockage de pétrole en utilisant l’hydro-fracturing et l’overcoring. La première mesure a étè faite pour le plan des cavités avant l’excavation et le seconde pour con-firmer l’état de contrainte durant l’excavation. Six measures ont étè faites dans le teste de l’hydro-fracturing à la profondeur entre –17.8 et 54.5m depuis l’élèvation maritime. Une seule mesure a étè faite dans le teste de l’overcoring dans une seule trou de songdage à la profondeur de –21m. Le ratios de la maximale contrainte horizontale à la contrainte verticale mesure par les deux méthodes sont 2.95 et 3.1, respectivement. Les orientations de la maximale contrainte horizontale sont N53E et N58E. Ce montre que les deux méthodes donnent presque m me résultats et la contrainte im-portante est activée sur ces cavités. Zwei Druckmessungen wurden durchgeführt auf der Erdoberfläche und im Innern von Ölspeicher-kavernen unter vergleichender Anwendung des Hydrofraktionierungs- und des Kernbohrungsver-fahrens. Die erste Messung wurde durchgeführt um einen Plan der Kavernen vor der Herstellung zu erstellen und die zweite um die Druckverhältnisse während der Bohrung zu überprüfen. Sechs Messugnen wurden mit der Hydrofraktionierungsmethode bei einer Tiefe von 17,8m und 54,5m unter dem Meeresspiegel und eine einzige Messung mit der Kernbohrungsmethode in einem Bohr-loch bei einer Tiefe von 21m unter dem Meeresspiegel vorgenommen. Das Verhältnis von maxi-malem horizontalem zu vertikalem Druck bei der Hydrofraktions- und der Kernbohrungsmedthode ist 2,95 bzw. 3,1. Die Bezugspunkte des maximalen horizontalen Drucks in beiden Verfahren sind N53E und N58E.

Jan 1, 2003

By M. Helm

Over the last 40 years, numerous investigations have focussed on the preg-robbing capacity of carbonaceous material during gold ore processing. Various techniques have been applied to characterize the physical and chemical properties of the carbonaceous material in efforts to predict its preg-robbing capacity. The present study, which forms part of an ongoing investigation, is specifically designed to increase the understanding of preg-robbing in ores containing carbonaceous material. In excess of 100 samples from 13 gold mines located in major gold provinces of the world have been incorporated into the present study. These samples were characterized using industry standard metallurgical techniques and were shown to have gold adsorption capacities ranging from a few grams to many hundreds of grams of gold per ton of ore. Further analysis showed that the crystalline nature of the carbonaceous material, which is related to its geological history, is important in determining the preg-robbing capacity of an ore. This finding builds on the common understanding that the preg-robbing behaviour of an ore is related to the amount (or abundance) of carbonaceous material present in that ore. In this study, Raman spectroscopy was used to evaluate the physical nature of carbonaceous material. This is a tool which has been successfully applied by researchers for the characterisation of carbon materials, with respect to crystallite size and lattice defects. Raman analysis of the samples included in this study showed varying degrees of disorder in the carbonaceous materials from the different deposits. Comparison of the Raman spectra with the gold loading capacities of the samples indicated a direct relationship between the structure of the carbonaceous material and its capacity to preg-rob gold. From this, a simple and robust method has been developed based on the Raman spectra of the sample and carbonaceous material content to predict the preg-robbing capacity of an ore. The potential exists to develop a predictive tool using Raman spectroscopy for characterising the preg-robbing capacity of an ore. Such a tool would have potential application in projects ranging from the early stage of exploration through to more detailed feasibility studies and mining operations. The result of applying the predictive method outlined in this paper would be the effective and proactive management of the deleterious influence of carbonaceous material on gold recovery in mining operations.

Jan 1, 2009

By P. Kitobo, T. Nduba, D. Mbay, J. B. Vangu, R. Ciband

The flotation plant tailings at Kamoa Copper Mine concentrator were found to contain a high proportion of extremely fine particles. The potential issues with settling these fine solids were resolved by the use of a poly-di-allyl-di-methyl ammonium chloride (DADMAC) coagulant, Flobead DB 45 VHM, in conjunction with a standard anionic polyacrylamide flocculant. This paper outlines some of the issues encountered and how they were resolved at the Kamoa concentrator. The potential to use this process and technology at other sites is also considered

Jan 1, 2023

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

This paper sets out to consider a specific type of corrosion protection system, which is referred to as a Duplex Coating system. The dictionary describes a duplex system as consisting of two elements or a “twofold” composition. The duplex system described in this presentation is such a two-part corrosion protection coating, viz, hot dip galvanizing as the firm base or primer, followed by a top paint system designed to combat severe corrosive environmental conditions encountered in nature. In principle, the duplex system is a cost effective and balanced, designed coating that is suited to the environmental conditions and service life requirements.

Jan 1, 2009

By G. Dellas, R. Mangera, A. Voigt

"X-ray transmission (XRT) sorting has become the preferred recovery technology option in several parts of the diamond-winning flow sheet. In the De Beers Group, applications of XRT are found across kimberlite, alluvial, and marine operations. This is the result of intensive R&D conducted over the years to arrive at a suite of machine embodiments capable of sorting and auditing diamonds across all size ranges.The first applications in the marine environment used the technology in an auditing mode, and served as a useful early predictor of diamond content weeks ahead of sorthouse returns. The same machines are now available with ejection capability to produce high final product grades. The next application was tests on coarse alluvial gravels as an alternative to dense medium separation. The results were very encouraging, and tests are planned for both green- and brownfield kimberlite environments, as well as to explore an alternative to conventional techniques in final diamond recovery. At the Jwaneng mine Large Diamond Pilot Plant (LDPP), the objective is to recover diamonds in the size fraction –45 +25 mm.The technical challenge remains in the finer sizes, for high-capacitymachines as direct alternatives to conventional diamond recovery technologies. This is an area of ongoing R&D and it is only a matter of time before the breakthrough emerges. X-ray transmission fundementalsXRT makes use of X-ray imaging techniques to analyse objects and materials, and has a wide range of applications from baggage scanning for security purposes (Martz et al., 2016), to recycling of waste material (Owada, 2014). During the last decade XRT has been applied to an increasing extent in the minerals processing industry (von Ketelhodt and Bergmann, 2010; Sasman, Deetlefs, and van der Westhuyzen, 2018). Dual-energy XRT (DE-XRT), in which images of the target material are obtained at both high and low Xray energies, allows for elemental analysis and therefore can be used to discriminate between various minerals.A DE-XRT system makes use of a dualenergy X-ray line scan sensor to generate images of transmitted X-rays (Figure 1). Dualenergy refers to the camera, which contains two sensors, one responding to low-energy Xrays and one to high-energy X-rays. Feed material can be imaged either while on the belt, or while in flight."

Feb 1, 2019

By F. M. Ramadhan, M. R. Pratama

Monitoring open-pit mine road conditions has become very critical nowadays. There are several benefits to in conducting research on this field such as opportunity to improve truck’s speed which directly influences truck’s productivity. This research aims to provide a semi real-time, and sensors-based automatic road damage detector that predicts the road quality through road damage exact location tracing, road damages auto-classification, and real-time instruction in the form of work order format to mining road maintenance, and repair authorities through mobile apps and maintenance unit’s in-cabin display. It will also provide the maintenance/repair activity performance evaluation via integrated dashboards. The artificial neural network algorithm is applied during the process of data training regarding classifying road damages and severities which resulted in a valid model. The road damage classification model has a precision level of 80.5% in predicting whether the road is damaged or not. Using this approach, we are expecting to visualise a road quality map of all active roads on mine site.

Sep 1, 2021

By E. Kumar, L. A. Kumar

"A methodology is proposed to develop an optimization model to understand the impact of transporting minerals, from mines to the final destination, on air quality. Recently, there has been increasing concern about the combined effects of multiple activities over many years, and the regional environmental changes brought about by a single project. Environmental issues in the iron ore industry have highlighted the need to broaden the cumulative impact assessment. In this study, we simulated the optimal routes and quantity of materials needed to meet the destination plant demand based upon environment constraints (level of air pollution), as well as the cost of transportation and availability of materials. Multiple scenarios were developed to analyse the effects of changes in routes, alternative transport system (or multi-modal split), traffic congestion, and the cumulative impacts on air quality. The air quality impact zones of the study area were demarcated using a GIS technique. The expected outcome of the study is the selection of a suitable transport system for a particular site with the least impact on air quality, including the transportation route, relative to the minimum cost of transportation of the minerals from the mines to their final destination. The proposed methodology is evaluated with a case study. IntroductionIn India, the process of environmental impact assessment (EIA) has been focused primarily on the local impacts of projects, without considering regional environmental effects. Environmental clearances for proposed projects are based on reports of local impacts. However, any developmental project poses a potential risk to the environment as a whole, and not just in the immediate vicinity of the project. Recently, there has been increased concern about the combined effects of multiple activities over many years—the regional environmental changes due to development of a single project (Dutta, Mahatha, and De, 2004). Environmental issues throughout the country, particularly in the iron ore industry, have emphasized the need to broaden the analysis to include the combined impacts, or those forecast for a proposed region, on an existing environment. The most significant adverse environmental consequences of iron ore transportation are the deterioration of biodiversity and air quality (Kumar and Ajay, 2015)."

Jan 1, 2017

By A. A. Hazell

Mine management by objectives by A. A. Hazel Published in the Journal, September 1972 DISCUSSION H. H. McGREGOR Mr Hazell is to be complimented on a thoroughly down to earth analysis of the uses ot which work study can be put and the benefits of properly applying it in the management of underground production.

Jan 9, 2007

By B. J. Ralph, I. J. Corrans, B. Harris

In the first section, a brief background to the practical and theoretical aspects of bacterial leaching is presented. Descriptions are given of present and potential methods for exploiting bacterial leaching in metal-winning. In the second section, the results of recent research are presented. The aim of this work was to obtain a greater understanding of the mechanism of bacterial leaching of sulphide minerals. Bacteria were observed to catalyse leaching reactions by oxidising ferrous ions to ferric ions, by removing protective films at the mineral surface and by depolarising cathodic areas.

By P. Geldenhuys, D. J. C. Taylor, D. C. Page

This paper gives a technical review of the history, occurrence, mining, and metallurgy of iron in South Africa. The reserves of iron ore worldwide and in South Africa are reviewed, and potential new developments In the iron-and-steel industry in South Africa are examined. The paper concludes that the exploitation of lower-grade iron deposits will probably supplement the reserves of high-grade hematite ore in the distant future, and that, accepting this scenario. South Africa will be well placed to provide iron ore for its expected internal steel requirements, as well as supplying quality Iron ore for the export market.

Jan 1, 1988

By J. M. Czaplicki

The problems connected with deep mine hoisting and the increasing complexity of this process can be analysed through the application of such mathematical tools as stochastic modelling to study the effectiveness, reliability or safety of hoist methods. To relate these theoretical investigations to real practice, knowledge about components, their stochastic nature and stochastic order of appearance is necessary. This paper presents results obtained during the ten-year (1976-85) period of research undertaken in the Polish mining industry by the Mining Mechanisation Institute of the Silesian Technical University, Gliwice, Poland.

Jan 1, 1987