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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. -T. Mutale, A. S. Tuling

Titanium can exist in three different oxidation states. Its oxides are numerous and in presence of iron and oxygen, iron-titanium oxide compounds can also form. Some of the oxides are non-stoichiometric, making the determination of the thermodynamic properties of titanium and its oxides in molten steel and in slag difficult. Therefore, for the assessment of titanium activity in molten steel using the electrochemical measurements of oxygen partial pressure, the identification of oxides in equilibrium with titanium is important. This paper reports on an investigation of solid titanium oxide inclusions, which have been identified by combining different methods of analysis on quenched samples. These samples were taken from a Fe-Ti-melt at 1600°C, quenched in cold water then mounted and polished for optical microscopy. The oxide inclusions were analysed using transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS). Both single crystal and polycrystalline diffraction patterns were used to identify the oxides by comparing the d spacings with those in the ICDD X-Ray Diffraction (XRD) database. XRD was used to analyse the oxide particles on the top of slow cooled samples. It was found in the TEM study that the similarity of the diffraction patterns of the various phases meant that unique identification was difficult to achieve in some of the diffraction patterns. However, TiO, Ti2O3, Ti3O5, Ti4O7were identified in quenched samples, while TiO2, FeO.TiO2and iron oxides were seen in slow cooled samples. It was also confirmed that the type of oxides is related to titanium content of the samples. Keywords: Titanium, Titanium Oxides, Iron, TEM, XRD, thermodynamic.

Jan 1, 2004

By Kurt RP Petersen, Hendriena van der Walt

With the decline in fine diamond production from the Argyle mine in Australia, there is a greater emphasis on efficiently treating the finer size fractions through a DMS circuit. Although it is generally well understood that smaller diameter cyclones are more appropriate for this application, practical results do not necessarily meet this expectation. In this paper the operational performance of particular sized cyclones throughout the group was compared. Based on the results there is evidence that under certain practical operating conditions, small cyclones are not necessarily best for fine size particle treatment, particularly given the production pressures faced by all mines. However, there seems to be considerable merit in using larger sized cyclones, which tend to exhibit less performance variability, irrespective of operation conditions.

Jan 1, 2006

By D. P. Roberts

This investigation aimed to simulate the experiments performed by Nic Gay (Gay, N.C. 1976. Fracture growth around openings in large blocks of rock subjected to uniaxial and biaxial compression. International Journal of Rock Mechanics and Minining Sciences and Geomechical Abstracts, vol. 13. pp. 231-243) on fracture growth around openings in blocks of rock subjected to uniaxial and biaxial compression, using the Elfen discrete element code. The results of the physical experiments indicated a number of trends that were successfully replicated in the numerical simulations, including crushing ahead of the face, the formation of a sub-vertical tensile fracture at centre-span, the formation of groups of fractures originating from the crushed face zone, the formation of large corner-to-corner fractures which precede sample failure, and linking of slot corner and sample corner fractures leading to sample failure. In addition, other features were apparent that were not reported by Gay. It is believed that these took the form of conjugate shear fractures (as reported by Gay in a previous paper) and other features that may have been altered or inhibited by the presence of pre-existing structure in the physical samples. It was found that the samples, though nominally made up of the same rock type, must have had significantly differing properties. The presence of pre-existing structures may have contributed to this discrepancy. Strain measurements from the physical experiments were reasonably well matched, except where the gauge lay directly in the path of advancing fractures.

Jan 1, 2012

By W. M. Jansen

In many mineral processing operations, the reported production figures for an accounting period may not make the best use of available data. While most of the mathematical approaches, such as check-in/check-out, mass balancing, used in effective metallurgical accounting strategies are well understood, the sources and magnitude of measurement errors generally are not. As part of the 'AMIRA P754-Metal Accounting and Reconciliation' project, a study was undertaken at the Northparkes copper/gold concentrator near Parkes, New South Wales to examine the data used in their concentrator metallurgical accounting system. This paper summarises the results of a detailed examination of the mass measurement systems around the concentrator as well as the primary sampling system used for grade estimation. The goal of this work was to develop practical techniques to quantify the error (ie both accuracy and precision) of the measured metal accounting information. With this information, statistical confidence levels for this data can then be calculated. If the errors are small, the effect of error in each piece of measured data can then be propagated to other calculated production figures such as recovery and feed grade using a statistical technique called `the propagation of error'.

Jan 1, 2007

Electricity supply constraints in SA are increasingly challenging mines to operate more energy efficiently without reducing production output. Mining compressed air systems are well known to be operated inefficiently and are also a major power consumer. Two available and proven technologies can be applied on new and existing mines to replace or and optimise available compressed air facilities and achieve meaningful reductions in electrical power consumption; ? Hydro powered drilling and mining is significantly more energy efficient than compressed air and provides drilling rates that are twice as fast. ? Stope drilling systems using compressed-air or water drills allow further energy savings. The technologies are discussed and a broad strategy to selectively apply these them together is presented.

Jan 1, 2008

By I. Jauhari, F. Stober, D. Fowler, B. O. Wasmund, T. Miraza, C. Nichols, A. Taofik Hidyat, K. Said

The existing PT Aneka Tambang (Antam) ferronickel smelter located at Pomalaa, Indonesia consists of two RKEF lines with reduction furnaces nominally rated at 17 MW and 18 MW, respectively. The low power densities and heat fluxes allowed both furnaces to operate with falling water film shell cooling systems. The furnace campaigns comprised a 5-yearly cold shut -down for metal taphole area rebuild and a 10-yearlysidewall and hearth perimeter repair. Towards the end of these campaigns the furnaces would typically be operated at below nominal power due to excessive sidewall temperatures. In January 2001 Hatch performed a smelter study which proposed options which indicated the possibility of a single furnace operation for the smelter, elimination of lime addition and transition to shielded-arc operation with associated efficiency and throughput gains. This paper discusses the process of uprating the second?line furnace capability from 18 MW to 32MW following the decision by Antam to implement the recommendations proposed by Hatch. It will cover the development of scaled-up furnace design basis by Hatch and Antam with the enabling application of Hatch cooling and binding technology. To optimise the capital cost and maximise Indonesian supply content and post installation support, the scope was carefully and clearly divided between Hatch and Antam. The challenges, set backs and valuable learning experiences gained during the implementation of the retrofit include; ?The support and re-use of existing roof system and challenges presented in re-use of existing crucible support steel. ?Training and technical assistance for Antam operators to perform refractory and copper cooler installation and maintenance of crucible integrity technologies. ?Hearth integrity during start-up and development of an initial charge and start-up procedure to achieve planned thermal expansion of the hearth prior to bath formation ?Implementation of a sidewall hold-down system within the refractory sidewall due to space constraints ?Existing furnace foundation reinforcement to overcome lateral forces on furnace piers during crucible support steel expansion ?Conversion of an open-loop gravity feed cooling water system to a closed loop pressurised system with integrated emergency gravity feed and backup system ?Existing water treatment system and pumping system improvement and modification to meet copper cooling system requirements ?Integration of the new instrumentation control system designed by Hatch to increase performance of the furnace monitoring system and operation ?Uprate transformer capacity from 25 MVA to 40 MVA to meet with requirement of Shielded- Arc Furnace Operation.

Jan 1, 2007

By G. E. Blight

Wind erosion can be a major cause of the loss and dispersion of tailings material from a tailings dam into its surrounding environment. Such dust dispersion can be a serious nuisance, as well as a health hazard to inhabitants in nearby settlements, and can also damage the health of animals, degrade crops, making them less marketable, and cause soil and water pollution. The problem of wind erosion can affect tailings dams in all types of climate, but becomes worse as climatic aridity increases. Because clouds of dust are often observed billowing across the top surfaces of tailings dams in dry windy weather, there is a common misconception that the dust arises from wind erosion of the top surface. As a result, much effort and money is vainly spent on treating the tops of tailings dams to prevent dust generation, whereas the slopes of the dams are the true major dust source. This paper briefly reviews what is known of erosion of tailings dams and then proceeds to describe the mechanics of wind erosion in general, and how it affects tailings dams in particular. Finally, recommendations are made for mitigating wind erosion of tailings dams and the resulting blowing dust.

Jan 1, 2007

By Z. Zhang

The author recently has reviewed the publications on the slag-related research in China since the Sixth International Conference on Molten Slags, Fluxes and Salts in June, 2000. In fundamental aspects, the physical property predictions and measurements, slag-metal reactions, slag-refractory reactions have received close attention, and are briefly described here in this report. More than half of slag-related publications deal with plant investigations due to the requirement of technological improvements and environmental protection. In the present paper, the research on slags in various treatments related to clean steel production and the utilization of the waste slags is briefly reviewed.

Jan 1, 2004

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 J. G. van der Watt

Due to increasing concerns of global rare earth element shortfalls in the near future, possible alternative sources of rare earth elements have recently become of economic interest. One such alternative is decanting acid mine water originating primarily from abandoned old mines in the Witwatersrand region of the Republic of South Africa. In this study, a novel way of rare earth element removal from the acid mine drainage was employed, making use of bentonite clay, which has very good adsorbent properties, as a rare earth element carrier material. The process can be economically viable only, if the elements can be selectively removed from the bentonite clay carrier material so as to yield reusable clay. Acid leaching was proposed to liberate the adsorbed rare earth elements from the bentonite clay. Accordingly, acid leaching experiments were performed to study the desorption of three commonly-found rare earth elements, namely neodymium, samarium, and dysprosium, from bentonite clay in the presence of sulphuric and hydrochloric acid. It was established that the three rare earth element species could be selectively removed as a group from iron, magnesium, and manganese metals through the careful manipulation of the pH. An investigation into the kinetic aspects of the rare earth element desorption process from the bentonite clay was also undertaken. The applicability of various kinetic models such as zero-order, pseudo first-order, pseudo second-order, elovich, parabolic diffusion, and power function were tested to describe the time-dependent desorption of rare earth elements from bentonite clay. It was determined that the pseudo second-order kinetic model represented the dissolution processes for neodymium, samarium, and dysprosium from bentonite clay the most accurately.

Jan 1, 2012

Keywords: Pyrometallurgy, furnace, Lonmin, platinum, PGM, UG2 Lonmin, earlier than any other primary platinum producer, had to deal with the concentrating and smelting of UG2-rich ores and concentrates respectively. Smelting was performed at a fairly modest scale compared to its industry peers in the Platinum Group Metals (PGMs) industry, and was focused on smelting concentrates obtained through low mass pulls while still maintaining high recoveries at its concentrators. Lonmin gradually smelted larger quantities of UG2 concentrates. Initially two 2.3 MW Infurnco furnaces were commissioned in 1982, followed by three 5 MW circular 3-electrode Pyromet furnaces in 1991. Deep electrode immersions and moderately high hearth power densities were used in all the designs. Lonmin decided to continue with circular furnace technology when it planned its new high-intensity No. 1 Furnace. Neither Lonmin nor the technology supplier and EPCM company foresaw the challenges that scale-up would bring when applied to the smelting of UG2-rich concentrate blends. Superimposed on the high chromite content, was the low base-metal loading, mineralogical difficulties, and fine particle size that came with milling of all concentrates (especially UG2 and recycle materials within the smelter). Through a process of fundamental diagnoses of furnace run-outs and wear patterns observed during repairs, the main challenges operating this high-intensity furnace were identified as sulphur vapour corrosion of the copper coolers, uneven and unpredicted movements of refractory bricks with associated copper cooler lift and matte tap-block movement, the formation of three-phase ?mushy? zones, high refractory and tap-hole wear rates, uncertainty in matte level and associated insufficient matte buffer height, and high furnace operating temperatures. These factors seldom worked in isolation and will be explored in more detail in the paper. The variability in furnace feed characteristics led Lonmin to re-design Furnace No. 1, to invest in back-up furnace capacity, and to invest in improved monitoring and control. These improvements consisted of online and high-frequency off-line feed chemistry and mineralogy monitoring, online pressure monitoring of water-cooled circuits, an alternative matte liquid level measurement in the furnace, and electrode immersion estimation. Improvements were also made at the converters by installing and utilising optical spectral analysis of the converter flame to characterise converter behaviour and achieve the desired iron end-point for white matte. This paper also briefly discusses the current and future expansion plans, as well as ancillary operations at the smelter such as flue-gas handling and materials handling.

Jan 1, 2011

By M. Kawakami, K. Suzuki, T. Takenaka, S. Yokoyama

Molten NaNO3-NaNO2-KNO3mixture is used as a heat transfer medium at high temperature. One of the most important properties of this mixture is the heat capacity. In the present work, the enthalpy change with temperature was measured by the drop calorimetric method to evaluate the heat capacity. The results are summarized as follows: The enthalpy of the mixture increased linearly with the temperature. From the slope of the line, the heat capacity was evaluated. The heat capacity of pure NaNO3, NaNO2and KNO3was 0.129,0.110 and 0.142 kJ/mol/K, respectively. These values are in fairly good agreement with the published data. In the binary and ternary systems, the molar additivity of heat capacity, which is well known as Neumann-Kopp’s law, was obtained. The heat capacity of HTS1and HTS2, which are well known ternary mixtures of practical use, were in the range of published data.

Jan 1, 2004

By J. Searra, M. Aboagye

"For new mining projects or for medium- to long-term areas of existing mines, drilling data is invariably on a relatively large grid. Direct estimates for selective mining units (SMUs), and also for much larger block units, will then be smoothed due to the information effects and the high error variance.The difficulty is that ultimately, during mining, selection will be done on the basis of SMUs on the final close-spaced data grid (grade control), which will then be available, i.e. the actual selection will be more efficient, with fewer misclassifications. However, this ultimate mining position is unknown at the project feasibility stage and therefore has to be estimated. This estimation is required because any cash flow calculations made on the basis of the smoothed estimates will obviously misrepresent the overall economic value of the project, i.e. the average grade of blocks above cut-off will be underestimated and the tonnage overestimated for cut-off grades below the average grade of the orebody. Similarly, unsmoothed estimates will be conditionally biased and will give even worse results, particularly in local areas of short- and medium-term planning or mining.This paper presents a case study of indirect post-processing and proportional modelling of recoverable resources designed for mediumand long-term mine planning at the Gold Fields’ Tarkwa Mine in Ghana. The case study compares long-term indirect recoverable mineral resource estimates based on typical widely spaced feasibility data to the corresponding production grade control model as well as the mine production. The paper also proposes certain critical regression slope and kriging efficiency control limits to avoid inefficient medium- to longterm recoverable estimates, and highlights the danger of accepting block estimates that have a slope of regression less than 0.5."

Jan 1, 2015

By W. D. Northrop

This paper gives an account of the development of a technique whereby the vertical limits of geological horizons may be identified by the use of vertical variograms on the mineral of economic interest. This information may supplement or guide the correct subdivision of the individual horizons into meaning full data sets by diligent geological observation. This process then improves the quality of the variance modelling of the gold distribution in the plane of the individual layers and therefore enables better estimates to be made into the grids or blocks of the mine model. The technique is explained by an account of the development work, which was performed, on duplicate superimposed reef horizons in the Kimberley formations. The paper then shows how the correct approach was developed to evaluate the mineralized layers in a multiple stacked conglomerate layer sequence in the Elsburg reefs of the Witwatersrand Rand System at the Target deposit. The method of categorization of resources according to confidence in the estimate is also explained. The feasibility processes carried out on the three-dimensional model, in accordance with the SAMREC code are also described. An example of the development of a reconciliation process utilizing chip sampling is also explained.

Jan 1, 2003

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 A. E. Hall, R. N. Taylor, J. G. Taylor

The introduction of tunnel-boring machines to South African gold mines has created problems and challenges which accompany any new technique. This paper describes the experience gained in this field, especially in the design and erection of a tunnel borer and in boring and environmental conditions.

Jan 1, 1978

Physical testing of rock support for rockbursting conditions has been carried out for over 40 years. A review of this testing shows that it has been mostly component?based, rather than actually testing support systems. Further, it is concluded that none of the testing is truly representative of rockburst loading in a similitude sense. Similitude conditions are not achievable, mainly because the real conditions in a rockburst event, such as seismic source location and magnitude, wave frequencies, amplitudes, and interactions, are not all known. Because such information is not available, and because the results of all testing carried out to date have not been able to define, for support design purposes, the capacity of support systems, ongoing physical testing of rockburst support systems is essential. It is essential that the test should simulate, or actually take place in, a supported rock excavation. A rock support system is a combination of individual support components that work together to retain and contain the rock. In doing this, the components are subjected to loading by the rock and to interactive loading between one component and another. It is necessary to prove the capacity of such rockburst support systems by subjecting them to severe loading, as in direct blasting. The direct blasting approach, pioneered more than 40 years ago, probably still provides the greatest validity as a significant test of rockburst support capabilities, even though it does not simulate a rockburst. Direct blast testing of rockburst support systems in a surface environment, such as in a quarry or on exposed rock cutting surfaces, could represent a practical development of the approach, facilitating the execution and monitoring of tests.

Jan 1, 2012

By S. F. Burks

"This paper develops themes explained at two SAIMM platinum conferences. Optimization techniques can be used to significantly increase the value of mining businesses by enabling better long-term planning decisions. Open pit and underground mine design, mine scheduling, cut-off grade and blending, stockpiling, and the linking of these to flexible elements of the metallurgical recovery processes are all evaluated together. Transport or sale of intermediate products and the requirements of the product metal markets can also be considered. Experience shows that net present value (NPV) can be increased significantly, usually even before the expenditure of significant amounts of project capital. Recent studies of NPV have aimed to simultaneously evaluate the impact of the optimized financial solution on the non-financial features of a project or operation.The case study presented comprised a commercially orientated review of the prefeasibility study designs and cost estimates of a platinum group metal (PGM) project in South Africa, followed by value chain optimization and sustainability studies of the project carried out simultaneously to identify potential value uplifts to be gained and guide the owners’ team going forward into the feasibility study phase. Some of the major aspects of the project that were found to have significant potential to add value included enhancement of the business model by the application of activitybased costing and theory of constraints, focus on the highest net value portions of the orebody in the early years of production, enhanced and optimized scheduling of the underground mining operation, application of dynamic grind and percentage mass recovery from ore to flotation concentrate (also known as percentage mass pull) to optimize revenue, application of elevated cut-off grades early in the life of mine, matching of the mining and processing capacity, expansion of the operation subject to capital availability, and installation of downstream processing facilities subject to regional third-party capacities.The investigation of non-financial project features focused on demonstrating that a financially optimized solution could also have a number of other benefits. These are mentioned briefly in the paper, which aims to present the status of the project at an early stage of its development."

Jan 1, 2016

By A. Mboma

Keywords: Furnace, decommissioning, care and maintenance, re-start, funding, nickel Bindura Nickel Corporation (BNC) operates two nickel mines, and treats concentrates from these mines as well as toll concentrates from the region around its Bindura Smelter and Refinery (BSR) complex. At the smelter, concentrates of at least 5% nickel content are blended and dried to 4% moisture in a coal-fired rotary kiln. Matte smelting of concentrate is carried out in a six-in-line electric arc furnace, where the furnace slag is granulated and discarded. Furnace matte is transferred via ladles into Peirce-Smith converters, where, after granulation, a leach alloy containing 68%Ni, 20%Cu, and 6%S is produced. Converter slag is recycled via the matte-smelting furnace. The onset of the global economic recession towards the end of 2008 resulted in a collapse of metal prices, worsening the local situation that was already marred by unfavourable macro-economic conditions in Zimbabwe. As a result, BNC mines were put on care and maintenance in November 2008, followed by Bindura Smelter and Refinery in February and March 2009 respectively. The business environment has since changed, and BNC is getting ready to re-start the plant. This paper describes the decommissioning of the Bindura furnace, asset preservation during the care and maintenance programme in the past two years, and preparation for starting up of the Bindura smelter in the near future.

Jan 1, 2011