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By R. E. Wilmot

This paper is based on the experiences, over many years, of numerous authors in the South African mining industry and of the hot dip galvanizing process and its application as a corrosion protection system. The paper sets out the extensive development, financial resources and stringent operating requirements of the South African mining industry. After many years of research and operational experiences, hot dip galvanizing and, when necessary, duplex systems, have been found to meet the demanding requirements of this particular industry. The paper sets out the requirements from the standpoint of corrosion criteria and is followed with a case where the corrosion protection properties of hot dip galvanizing are demonstrated. This case history traces the early investigation of the expected corrosive conditions in a new mining operation and concludes with two follow-up visits to the mine in order to examine actual performance of the corrosion protection system after ten years in service.

Jan 1, 2007

The latest Draft MPRRB was released for public comment in October 2006. The main purpose of the Bill is to collect royalties at mines developed in terms of new-order mineral rights granted through the MPRDA process. The transition phase stipulated in the MPRDA will be completed by 1 May 2009, on which date mineral royalties will become payable to the state. The royalty rates stated in the MPRRB differ from mineral to mineral and also depend on the degree of refinement. Gold is the subject of this paper, where the royalty rate ranges from 1.5% (for refined gold) to 3% (for unrefined gold) of sales revenue. This royalty is payable regardless of profit, with a maximum 75% relief for loss-making mines. The purpose of this paper is to establish whether or not it would be necessary for gold mines to adjust their mineral reserve statements as a result of this Bill. The methodology is to add the royalty costs stipulated in the MPRRB to the actual quarterly information for the past ten years as reported by the gold-mine members of the COM. The rationale is to investigate the impact this Bill (in its current form) would have had on gold reserves that must be left unmined in the ground because of a higher pay limit. The results of the study point to a significant impact on reserves available for mining with the subsequent shortening of mine lives and retrenchment of workers. Had the MPRRB been effective for the 10 years prior to 1996, it would have resulted in 46 tonnes of gold being sterilised. Stated alternatively, 30 700 workers at COM gold mines alone would have lost their livelihoods.

Jan 1, 2007

By D. J. Steynfaard

Sishen Iron Ore Mine is situated 280 km north-west of Kimberley in the Northern Cape Province of South Africa. The mine produces and sells high quality iron ore of various specifications to various national and international clients. The saleable product is derived from the blending and beneficiation of different types and qualities of hematite iron ore. This paper documents the new developments which were implemented (or are in the process of being implemented) on the mine in the long-term planning, medium-term planning, grade control and material tracking in the beneficiation plant with special attention being paid to the quality of the final, saleable product. The process starts with the long-term planning where the pit shell and pit optimization is determined by Whittle 4X. New developments include the introduction of a linear programming based scheduling system to enhance the long-term schedule generated by Whittle 4X. The LP route was decided on in order to take into account all the constraining factors of the final product that could not be configured in Whittle. To complement this the XPAC Auto Scheduler scheduling package was introduced to do the medium-term mine scheduling. This 18-month rolling plan includes cost parameters to enable the planner to extract a detailed operational budget from the scheduling while ensuring that production standards are maintained and grade constraints are met. The existing grade control system was enhanced with GPS capabilities and a computer system to do material tracking. The high precision GPS system introduced on the shovels allows for the accurate control of the loading procedures at the mining face. Because of the complicated geology and grade composition of blasting blocks it is imperative to accurately differentiate between different materials in the same blasting block and being able to excavate that with the loading equipment. The GPS system on the trucks allows for accurate location monitoring of dumping in order to keep track of specific material types. The state-of-the-art material tracking system developed for Sishen will enable the grade control officer to keep track and record various parameters of the material from its in situ position in the blasting blocks, through the crusher and onto different stockpiles, in various stages of the beneficiation process and onto the blending beds, into the dispatching trains and eventually into the ships for international distribution. These developments elevate the Sishen planning and grade control systems to a new level of service excellence from which management can obtain accurate and timely information on product status. It also enables Sishen to maximize resource utilization while still complying with the tough market constraints.

Jan 1, 2003

By J. Kunze, R. Degal

During the last 100 years, the submerged arc furnace has been one of the most amazing diversified melting units. These furnaces have found their application in more than 20 different main industrial areas such as iron, ferro alloy, chemical industry, lead, zinc, copper, refractory, titanium oxide, recycling, phosphorus etc. Such an evolution was only possible because of tremendous efforts in research and development and due to the large range of design solutions. The worldwide strong competition also forced the industry and plant suppliers to develop highly efficient, economically balanced units in optimized sizes and with long lifetimes, to adapt to the market conditions. Regarding the environment, the plants improved significantly in terms of water treatment plants and off-gas treatments as well as on site recycling units. This paper will give a short overview regarding the history of the furnace and the latest developments in today?s main application fields: ferro alloys, non-ferrous, special application and recycling. In addition new activities in research and developments are briefly discussed.

Jan 1, 2004

By B. P. Watson

The Bushveld platinum group metal deposits are two distinct, shallow-dipping stratiform tabular orebodies which strike for many hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 300 m. The mining method is a variation of planar open stoping. Pillars are widely employed to support the open stopes. In the deeper levels, in-stope pillars are required to fail in a stable manner soon after being cut, and the residual pillar strength is used to stabilize the hanging wall. These pillars are commonly known as crush pillars. Little work has been done in the past to determine pillar peak and residual strengths, and pillars have been designed using experience and formulae developed for other hard-rock mines. This has led to over and undersize pillars with consequential loss of ore, pillar bursts and potential collapses. This paper describes a crush pillar design methodology, and provides design charts. Three mining environments were incorporated in the investigations, which included underground and laboratory measurements, analytical solutions, numerical model sand back analyses. The results of the study are suitable for the areas where the research was carried out, and may also be applied with caution in other similar environments.

Jan 1, 2010

By T. Mwanza, B. N. Belford, P. Conradie

"Metix has introduced a three-piece ’deep-cooled’ copper slag tapblock into a six in-line copper matte settling electric furnace. The tapblock was designed without any internal refractory; it relies purely on the development and maintenance of a freeze lining on its hot face and within the tapping channel to protect the copper and promote the integrity of the surrounding endwall refractory lining. In addition, the geometry of the tapblock further supports the sidewall refractories, reduces the impact of funnelling and, therefore, the need for premature rebuilding of the furnace endwall, and facilitates easy removal and replacement of the wear components even under ’hot’ furnace conditions. Eighteen thermocouples embedded in the copper components ensure full resolution of the copper condition, enabling plant personnel to identify wear rates, estimate freeze lining thickness and stability, and schedule replacement of spares and wear components well in advance.At the time of writing the tapblock had been in operation for 6 months with approximately 350 000 t of slag having been tapped through it. Every indication is that the design will limit the need for premature relining of the furnace endwall due to rapid deterioration of the tapblock and its surrounding refractories. IntroductionNonferrous furnaces rely heavily on the maximization of refractory campaign life to increase profitability and reduce planned downtime. In large electric copper slag-cleaning furnaces utilizing insulating linings, campaign lives of six or more years are realistic if consideration is given to each aspect that can degrade the refractory lining during the campaign. An area that is particularly vulnerable is the slag tap-hole and the local surrounding refractory. To avoid premature relining of the furnace walls, every effort should be made to consider not only the tap-hole design itself, but also the selection of the sidewall refractory material and its construction immediately adjacent to the tap-hole, and furthermore the interplay between the tapblock and this adjacent refractory. A holistic approach to the design that considers these interdependent features in the slag tapping area can reduce the incidence of accelerated refractory wear (‘funnelling’), support the surrounding refractories to prevent their collapse, introduce easily replaceable wear components that can be exchanged with the furnace still ‘hot’, and encourage and maintain a stable freeze lining at the refractory hot face that maximizes the tapblock and refractory lifetime."

Jun 1, 2019

By J. M. Ortiz

This paper shows the usefulness of geostatistical conditional simulation combined with the quantification of sampling errors obtained from the analyses of fundamental errors ? validated from duplicate data ? to assess the relevance of the quality and quantity of the information, for short-term mine planning purposes. Traditional blast-hole drilling equipment has been designed for efficient drilling, but not for obtaining high-quality samples. Furthermore, blast-hole sampling interferes with production, and thus usually produces poor-quality results. These results are the basis of short-term plans, where the grades of selective mining units are estimated and used for distinguishing between ore and waste. Under these conditions, misclassification (ore blocks sent to the waste dump and waste blocks processed at the plant) is inevitable, leading to significant hidden losses that can amount to millions of dollars per annum. Reverse circulation drilling with the latest automated sampling technology improves significantly the quality of the information used for short-term planning, and thus reduces misclassification, improving the financial returns of the operation. In this paper, we present the general methodology for assessing the effect of poor blast-hole sampling, as compared to advanced reverse circulation drilling grids at several spacings, in order to arrive at the most appropriate grid for short-term planning. This plan can be prepared well in advance using several additional variables that are usually not available when the plan is based on blast-hole samples. Furthermore, blending options can be analysed in order to optimize plant recovery, minimize the use of sulphuric acid, etc. Three case studies are presented, namely a typical porphyry copper deposit, an exotic oxide copper deposit, and a complex gold deposit, where mineralization is controlled by structures and lithology. This paper shows that in all cases, advanced reverse circulation drilling grids provide good-quality information that, coupled with the use of geostatistics for short-term mine planning, significantly improve the financial returns of the operation.

Jan 1, 2014

By M. Salimov, J. Sattarvand

The conventional visualisation method of remote equipment is through the installation of one or more cameras on the machine, and sending a live feed to the operator’s flat display. However, the performance of the teleoperation can be enhanced using better visualisation through virtual reality (VR). This paper presents the process of the design and manufacturing of a robotic platform that will be used in the next phase of the project for a VR-assisted teleoperated excavator. The robot consists of a loading boom and arm arrangement installed on the undercarriage of a CAT300-9D. All hydraulic cylinders are replaced with electric actuators, and crawling motors are substituted by electric motors. The pieces of the boom and the arm, as well as the bucket were designed in Autodesk Inventor, and manufactured from aluminium sheets using a desktop and CNC machine. Parts are joined by pins and welding as needed. An Arduino-based control system is developed for the robot, and motor controllers are used to convert the power commands from the microcontroller to the high-amperage actuators. The control system is capable of communicating with a wireless Play Station controller to operate remotely. The manufactured robotic excavator is planned to be utilised in multiple autonomy research projects.

Sep 1, 2021

By C. Dauber

Implementing new technologies in industrial operations entails the challenge of measuring the improvements gained by the applied technology. Nevertheless, it is absolutely essential to assess the technical and economic benefits in objective and comprehensible numbers to create a platform for further management decisions. Underground coal mines are characterized by numerous, quite complex procedures which make it difficult to determine the specific economic benefit of a new machine, technique, or method. In the OPTI-MINE Project funded by the European Union?s RFCS programme, five underground coal mines applied the latest information and communication technologies (ICTs) to improve efficiency, mine safety, occupational health, and environmental im-pacts. An integral part of the project is the assessment of these technologies by using key performance indicators (KPIs). The paper will describe some examples of the selected KPIs and the preliminary findings.

Jan 1, 2014

By S. J. Oosthuizen

This article explores the Fray Farthing Chen (FFC) Cambridge process, a novel method for the electrochemical deoxidation of metal oxides in molten salt, discovered at the University of Cambridge in 1997. The process was hailed as a highly promising, potentially low cost, novel method for the production of titanium metal direct from its oxides. The article should inform researchers in the field of some of the challenges in the commercialization of a novel, high profile process involving multiple stakeholders. The author, former senior process engineer at British Titanium Plc, the company originally tasked with commercializing titanium production via the FFC Cambridge process, reviews the latest literature and discusses past and present progress in the pursuit of low cost titanium metal via this process. Topics explored include the history of the process, attempts at commercialization, NASA?s alternative application, and present status of the process. Keywords FFC Cambridge, titanium, molten salt.

Jan 1, 2011

By P. K. Sahoo, C. R. Ray, S. S. Rao

Good operation of Soderberg electrodes is dependent upon high quality electrode paste coupled with better electrode management procedures. Without having a good electrode operation, it is not possible to obtain the best outcome from the furnace. In other words that is a good way to say how important the proper electrode operation is. Good electrode performance depends on the slipping rate and current levels, which decides the shape of the baking curve at the level of just below the contact clamps. Negative curvature of baking zone in the central part is considered dangerous because shrinkage takes place outwardly creating abnormal stresses in the electrode. Soft breakages occur when the baking zone comes below the clamps and the casing cannot take the current. This paper deals with various factors affecting baking characteristics leading to soft breakages and also presents case studies in a closed 48MVA furnace with smelting for charge chrome. In case studies in a closed furnace, it has happened that the energy for baking at the low current operation before breakage has been lower than the actual slipping has demanded. At low current there should not be problem, but a problem can occur when the current for some period is raised above the current carrying capacity of the casing. So data for electrode operation in actual period was studied and presented in this paper.

Jan 1, 2007

By R. Degel

Keywords: Pyrometallurgy, DC furnaces, electric smelter, FeCr, FeNi, FeMn, Si metal, ferro-alloys, platinum production, circular furnace, energy recovery system In 1906, the first submerged-arc furnace was supplied by SMS Siemag. Since then, the division has become established in various industries such as ferro-alloys and non-ferrous metals, and in numerous other special applications. During the evolution of this technology, more efficient units with longer lifetimes were developed. Today, especially the potential of DC-based smelters, raises worldwide attention, with some projects having already started to implement this kind of technology. This paper evaluates SMS Siemag?s general viewpoint regarding the potential application of DC smelter technology and possible options for the ferro-alloy and non-ferrous industry. SMS Siemag is currently executing a FeCr project in Kazakhstan, where four of the world?s largest closed-type DC smelting furnaces, with a power input of 72 MW, will be installed. These furnaces include the latest technological features of modern DC smelters, which are described in this paper. SMS Siemag has started a long-term research and development project allowing a direct comparison of AC versus DC technology on a large scale, using a recently installed 1 MVA test furnace at the IME at the University of Aachen, in Germany. For open-type ferro-alloy and Si-metal furnaces, SMS Siemag has developed an energy recovery system, which is presented in this paper.

Jan 1, 2011

By S. Pule, Z. Ndabezimbi, A. Hefer, E. Cupido

This article outlines various projects implemented at Rand Refinery to reduce effluent generation and freshwater consumption. The refinery generates about 2800 m³ of effluent annually and has initiated projects such as granulation water recycle and silver leach optimisation to address these issues. The granulation water recycle project has successfully reduced effluent volumes, while the silver leach optimisation has further decreased effluent by implementing stoichiometric addition of HCl and NaClO3. The vibratory shear enhanced processing (VSEP) trial showed promising results for gold recovery from wastewater, though further trials are recommended. The water savings of the effluent reduction projects are monitored by measuring the amount of effluent pumped to service yard effluent storage facilities with the use of flow meters connected on SCADA. Since the effluent reduction initiative of granulation effluent recycle in FY23, the effluent reduced to 2676 m³. In FY24, the stoichiometric addition of HCl and NaClO3 was implemented in the silver leach process, further reducing the effluent to 2083 m³.

Mar 5, 2025

By Z. Saw, C. Poveda, N. L. Mai

Optimising the throughput of a mining network comprising all equipment from shovels to semi-autogenous grinding (SAG) mills is a complicated task, yet the potential benefits can be significant. Key modelling challenges stem from the sheer number of possible routes which material can travel, different equipment operating under different constraints, and the rate of SAG mills being calculated through a nonlinear function of the blended materials’ rock attributes. Nevertheless, this is an ideal onapplication area of mathematical programming, a branch of operations research. This paper describes an application of mixed integer linear programming (MILP) to optimise the mining equipment network of one of the world’s largest copper mines.The model takes as input a year-long monthly mine schedule of shovels in different pits, pushbacks, sequences and faces which produce material to be moved through a network of crushers, conveyors, silos, distributors, stockpiles and SAG mills, ultimately outputting a daily operational plan for all equipment that maximises the throughput of the network. All operational constraints and business rules are considered, including three quality attributes of copper ore. Comparing model results with actual data shows an improvement of 4.47% in network throughput tonnage. Additionally, although the model is solved using a free, open-source solver, optimal solutions are still achieved within a practical timeframe.

Sep 1, 2021

By R. C. D. Phillis

The annual mine planning process is one of the most important tactical/operational steps towards achieving strategic goals. These tactical plans are part of a very comprehensive Mineral Resource Management process, with the natural sequel to planning being execution. The execution of an underground hard rock mine plan is a multi-project environment that comprises many development-construction-equipping-stoping single project paths, which are referred to as ?stoping paths?. The uncertainty that typifies execution of projects comes in the form of untimely disruptions to constituent tasks and/or project paths. Annual mining plans also include quantified objectives for occupational health and safety, production, quality, cost, employee morale, environment, and corporate social investment. Such objectives make for a highly complex environment that management must contend with?complex in the sense that all the paths and objectives have interdependent constraints. Furthermore, at the time of this paper, Sections54*and 55**of the MHSA*** put the onus on management to ensure legislative adherence. It stands to reason that planning estimates allow excess capacity?buffers?that cushions the impact of untimely disruptions. This paper concerns the fact that despite all the buffers allowed for, time, scope, and budget creeps impact on mine planning and threaten its successful execution. As a consequence, the paper deals with buffer management, the essence of Critical Chain Project Management (CCPM). Effective buffer management provided strategic (executive level) updates without losing the tactical/operational detail necessary for job card creation, especially where professional skills and experience are in short supply. Indicative bottom-line results showed CCPM to be highly effective.

Jan 1, 2011

By F. Rwere, A. Masasire, P. Dzomba, M. Mupa

Accurate determination of platinum group metals (PGMs) and gold (Au) has always proven to be a difficult task, due to their low concentrations in platiniferous ores. The most common preconcentration technique used in analysis of these metals is fire assay with a flux containing nickel or lead. This technique can be improved by using co-collectors. Here we hypothesise that Fe, Co, and Cu can be used as co-collectors to enhance separation and preconcentration of PMGs and gold by fire assay. To test this hypothesis, geological exploration samples from Siyanda Union Mine (Northam, South Africa) were analysed by an inductively coupled plasma-optical emission spectrometer (ICP-OES) for PGMs (Pt, Pd, and Rh) and Au. A control sample (certified reference material AMIS 0426) was also analysed by the same technique. The PGM and Au recoveries from the control sample ranged from 83% to 105% for all three co-collectors, with relative standard deviations less than 10% for the control sample and 7% for the geological samples. The PGM and Au recoveries by Fe and Co co-collectors were modestly higher than that of the Cu-collector. These results indicate that Fe and Co are better co-collectors than Cu, presumably due to the loss of analyte when using Cu. Taken together, Fe and Co co-collectors can be viable alternatives for analysis of PGMs and gold using the fire assay method.

Jan 2, 2022

By Braam Blom

PK2 Ventilation shaft is part of Paardekraal No 2 twin shaft system that is being developed to replace depleting Merensky reef production at Paardekraal shaft complex. The sinking team at this shaft faced considerable challenge of improving the total sinking cycle in order to be able to deliver the fully equipped shaft on time and on schedule. The cladding support cycle was identified as the tedious and time consuming activity in the overall shaft sinking operation. Reduction in the time required for handling and setting up the support installation equipment, and the time required for subsequent installation of the necessary support has a direct impact on the overall cycle time, and consequently the overall productivity and efficiency of the sinking operation. This reduction in support cycle was achieved by making use of machine carousel. The objective of this paper is to describe the support methodology that was used during the ventilation shaft sinking and the use of the machine carousel to reduce the cladding support cycle. The machine carousel replaces the traditional use of machine kibble in conventional vertical shaft sinking and has been designed specifically for installation of sidewall support at the shaft bottom during the sinking process.

Jan 1, 2009

By R. Thomason

Thank you Dr Barcza, President of the South African Institute of Mining and Metallurgy, for inviting me to share our experiences in Australia as regards the competency movement and my Association?s experience in assisting engineers become managers. This is my second visit to South Africa, and I am struck by the similarities between our countries. This extends to the professional issues associated with engineering and competencies in particular. I propose to outline two exciting stories today. ? Development of competency standards for professional engineers in Australia. ? Development of a management programme which has assisted professional engineers regain positions of leadership in Australian industry and government. First of all I would like to outline the Association of Professional Engineers, Scientists and Managers, Australia(APESMA).

Jan 1, 1997

Pyrometallurgy has played a very important role in southern Africa for at least four centuries. It continues to do so, and recent years have seen many exciting developments in pyrometallurgical technology. The wonderfully diverse rich mineral deposits in this area of the world have provided some unique opportunities for industrial processes to be established. The ?Southern African Pyrometallurgy 2006? conference was set up to showcase southern African pyrometallurgical operations, and to provide a forum for the exchange of ideas between people working at various types of smelters. Papers have been obtained from a wide variety of pyrometallurgical plants in southern Africa. These descriptions of plant operations (as well as some history, and highlights of current work) will provide useful reference information for some time to come. Contributions are also included from universities, research organizations, and engineering companies, so that the full spectrum of pyrometallurgical activities can be covered. The plant descriptions will be published on a website, where they can be updated as and when required, with the eventual goal of having a description of every smelter in the region. The conference venue was selected to be the 'Cradle of Humankind' world heritage area, about 40 km from Johannesburg. Not only does this keep the conference within easy reach of the city and yet far enough out into the countryside to allow people to focus on the conference, it is also within easy reach of many pyrometallurgical plants. There is a particular significance to the choice of location, in that the Swartkrans area close to the Sterkfontein Caves is the site of the earliest evidence of the deliberate controlled use of fire by human beings (about 1.3 million years ago), and this is obviously a necessary precursor to pyrometallurgy. The area also lends itself to a very wide range of outdoor, social, and cultural activities to supplement the technical content of the programme. It is hoped that activities such as a hot air balloon safari and visits to the world-renowned Sterkfontein Caves and Wonder Cave will help to make the conference a memorable one for those able to attend. I trust that the ongoing value of the papers and presentations will make all the hard work of the many contributors most worthwhile.

Jan 1, 2006

By M. B. Fonseca

Risk quantification in grade-tonnage curves is critical for capital investment in mining projects and can be obtained through geostatistical simulations of orebodies. A practical difficulty may arise in multi-element deposits, as the joint modelling of the related attributes using the traditional co-simulation approaches is computationally intensive and may be impractical for use in the industrial environment. This paper presents the construction of risk-integrating grade-tonnage curves for a complex copper deposit in northern Brazil, by jointly simulating its key geochemical attributes of interest: Cu, Fe and K. The joint conditional simulation of these elements is based on Minimum/Maximum Autocorrelation Factors (MAF). MAF is an approach, based on principal components, that spatially decorrelates the variables involved to non-correlated factors. MAF’sspatial decorrelation at any lag distance is the main and critical difference of this approach from the principal component approach attempted in the past. In the MAF approach, the independent factors are individually simulated and back-transformed to the conditional simulations of the correlated deposit attributes that reproduce the cross-correlations of the original variables. Keywords: Joint simulation; mini/max autocorrelation factors; grade-tonnage curves.

Jan 1, 2003