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By A. Beitz, P. Smartt, G. Einicke, G. Rowan, P. Glynn

Coal is Australia’s highest export earner and Australia is the world’s largest exporter of coal. With coal now being extracted from deeper reserves under increased risk profile, and in the interest of aiding the stability of coal supplies, Japan is funding a number of safety projects in Australia and China. The CSIRO, Australia’s premiere research organisation with the country’s largest exploration and mining research group, are currently undertaking a jointly funded Japan-Australia safety project at Anglo Coal’s new Grasstree Colliery in central Queensland. The project, entitled Mine Communication and Information for Real-time Risk Analysis, will deliver step-change capabilities in data integration, decision support, gas monitoring, geo-technical monitoring, emergency response and personnel safety to the Grasstree Colliery. Some key activities include: developing and installing underground coal mine Ethernet LAN components, real-time monitoring of gas and geo-technical sensors, MODBUS serial to TCP/IP converters, e-reporting of underground conditions, emergency guidance systems and underground trials of Internet Protocol telephone and video. The project seeks to integrate (in real time) key data sets from the comprehensive and diversified range of propriety system currently in use at mines (ventilation, strata, operations e.g. haulage, pumps, conveyors etc) into a single integrated risk management interface. This interface will filter the data through a rules-based inference engine that will cross reference the various data streams, compare with past events and outcomes associated with the similar historical data and present this “intelligence” to

Jan 1, 2003

A single aggregate mix design was developed based on a slag/Portland binder blend and crusher sand. The primary design criterion, after performance, was the fluidity of the shotcrete and concrete product to ensure compatibility with existing manufacturing and shotcrete equipment as well as the pipeline transport system Cullinan Diamond Mine was investigating. Initial work had determined an optimum slag/Portland to aggregate ratio while retaining a water to slag/Portland binder ratio of approximately 0.4 to maintain the flowability of the product. A super-plasticizer was used to further increase the flowability of the product as opposed to increasing the water content. Finally a polypropylene reinforcement fibre was included in the wet shotcrete product to improve the energy absorption characteristics of the shotcrete. Previous work on the strength development of the slag/Portland based shotcretes and concretes suggests that strength class based on the EN 206 specification is C40/50 while the toughness classification based on the EFNARC plate test is c, or greater than 1000 joules1. Typically, Cullinan Diamond Mine wanted a shotcrete with a uniaxial compressive cube strength of 45 MPa and an energy absorption, based on the EFNARC plate test, in excess of 700 joules. This is an EN 206 strength class of C36/45 requiring a uniaxial compressive core strength of 30.5 MPa and a toughness classification of b1. In addition to the shotcrete development, Cullinan Diamond Mine required concrete products with a compressive strength range of between 25 and 60 Mpa for differing construction operations underground to be manufactured from the same mix design and raw materials as for the shotcrete. Finally, Cullinan Diamond Mine carries out extensive dry shotcrete operations and an investigation into the possibility of using the single aggregate mix design for dry shotcreting was also entered into. This paper presents data that indicates that, under the terms of reference, a wet and dry shotcrete and concrete product appears to be possible from a single aggregate less than 6.7 mm in size, and that a slag/Portland binder is suitable for use as the hydraulic binder in all the products, and that the necessary performance parameters of strength and energy absorption can be achieved.

Jan 1, 2006

The development of 3D multi-parametric models facilitate the provision of resource information well in advance of the mining face. Using the model, one can evaluate mining areas not only for grade and tonnage predictions but also for predictions of rock mass quality. Blast design and milling requirements can be derived from the rock mass quality predictions. This information can be used for overall mine planning and evaluation, costing, production optimization and slope design. This allows the full range of mining activities and costs to be interconnected, thereby lowering costs and improving efficiencies through the application of the multi-parametric model. Feasibility studies for new projects require an expected budget expenditure estimate to within 5% of actual costs. This level of accuracy is expected by mining companies and investors but cannot be achieved without a sound knowledge of the rock mass variability. By developing a 3D multi-parametric model as part of the feasibility study and using the same geological model exploration boreholes, a significantly better understanding of the rock mass conditions can be obtained. This rock mass information can be used for equipment selection, economic pit layouts, processing plant design, underground mining layouts and support requirements, to name but a few design parameters that depend on rock mass conditions. The initiative at Anglo Platinums, Potgietersrust Platinum Ltd.?s (PPRust) operation, has delivered significant results showing improvements across the mine to mill value chain. These include increased loading rates, reduced electricity and crushing consumables, as well as higher plant throughput. The ore reserve model has gained international acceptance as an invaluable tool for a mining operation. Certainly most financial organizations will not invest in a mining project that does not have an ore reserve model. There is the potential for multi-parametric models to be recognized as vital tools in the mining process, as is the case with ore reserve models.

Jan 1, 2007

By F. T. Cawood

?It is in the interest of stability and investor confidence that the healthy and necessary debate on such a (minerals) policy should soon find its way to consensus.? (President Nelson Mandela at the104th (1995), AGM of the South African Chamber of Mines) Inauguration of the new political dispensation in South Africa initiated a dynamic period in the historical development of its minerals policy. The process of substituting the current South African mineral policy framework with an acceptable ?post apartheid? system, started soon after the 1994 election of the African National Congress (ANC) government. The Green Paper on a Minerals and Mining Policy for South Africa released for public discussion in February 1998, calls for radical transformation in mineral rights ownership. A shift towards exclusive state ownership of mineral rights, away from the present dual system of private and state ownership, is the most significant proposal. The current holders of mineral rights, or their nominees, who lawfully enjoyed security of tenure under past and present mineral laws are opposed to this transformation because mineral rights were often acquired at considerable cost. The situation is compounded by poor public record-keeping and passive mineral rights administration over a very long period. This paper represents a summary of the historical developments leading to the current legislative environment and forms the basis for any discussion on which future sculpturing of South Africa?s policy regarding mineral rights can take place. One cannot plan for the future without considering the past!

Jan 1, 1998

By H. Hamma, R. Fehrmann, M. Gaune-Escard, G. Hatem, S. B. Rasmussen, K. M. Eriksen

The molten salts M2S2O7and MHSO4, the binary molten salt systems M2S2O7-MHSO4and the molten salt-gas systems M2S2O7-V2O5and M2S2O7-M2SO4-V2O5(M = Na, K, Rb, Cs) in O2, SO2and Ar atmospheres have been investigated by thermal methods like calorimetry, Differential Enthalpic Analysis (DEA) and Differential Scanning Calorimetry (DSC). Fundamental thermodynamic data like temperatures and molar heats of solid-solid transition and fusion, phase diagrams, heat capacities of solids and liquids, heat of mixing, and heats of complex formation have been obtained and are reviewed here. Also EPR spectroscopic evidence of V(IV) complexes and their structure are reported and the results are discussed in relation to the mechanism of SO2oxidation by V2O5based industrial catalysts. Keywords: Alkali pyrosulfates, alkali hydrogen sulfates, vanadium pentoxide, EPR spectroscopy, complex formation

Jan 1, 2004

By M. R. MacIver, M. Pawlik, S. Finora, H. Alizadeh

The dispersion of mature fine oil sands tailings (MFT) by the addition of sodium lignosulfonate was studied using contact angle measurements, optical scattering, and particle size measurements. Lignosulfonate caused the release of residual bitumen to the slurry surface and settlement of fines. Dynamic contact angle by captive bubble measurements were carried out on bitumen to determine the effect of the dispersant on the wettability of bitumen. Lignosulfonate caused a change in the aggregation state of the MFT and increased sedimentation of particles, as indicated by optical scattering measurements. Zeta potential measurements indicate that this change was caused by an increase in adsorption of lignosulfonate onto particles, which caused improved settling of the colloid. Ultraviolet Visible (UV) spectrophotometry and organic carbon content measurements showed that only a small amount of the reagent remains in the aqueous phase of the tailings, which is critical for decontamination of recycled water. Keywords: Oil sands tailings, bitumen recovery, dewatering, dispersion, surface chemistry

Jan 1, 2020

By Kurt R. P Petersen

This paper discusses the current approaches to modelling the DMS cyclone within the De Beers group. Current efforts are split into short term value-adding process understanding and longer term semi-fundamental analysis of separation mechanisms. To date, the basic applied approach has yielded significant value to the group, enabling operators to focus on simple diagnostic measures to control their process. The more involved modelling approach has given rise to a new understanding of the separation field, in particular that the high density gradients within a cyclone are highly localised, indicating that separation of medium to heavy density material takes place low in the cone. The model has proven to be conceptually robust, but still requires further development and validation to become a complete modelling and simulation tool for De Beers.

Jan 1, 2006

By D. Tesh

The mining industry worldwide is facing a tremendous shortage of minerals engineers in all fields of specialization. For instance, in Australia the skills shortage in the mining industry has been identified as one of the top risks facing the mining industry. In Namibia most minerals engineers employed are expatriates, with some being Namibians who studied abroad. The minerals engineering programmes at the Polytechnic of Namibia are still in their infancy. These programmes were designed to meet the mining industry skills needs. Being young has its advantages in that lessons can be learnt from older minerals education institutions that went through similar challenges. However, this does not imply just copying and implementing their approaches, since the context differs and, to ensure sustainability of the minerals education programmes, curricula have to be customized to the local context. This paper reviews the interventions made by the Polytechnic of Namibia in order to ensure the sustainability of its minerals education programmes. The methodology consisted of an extensive literature review, a status quo analysis of the mining and process engineering department, identifying the gaps between the current state and desired state, and mapping the goals and strategic actions required to progress to the desired state. The following factors were identified as major threats to the sustainability of minerals education at the Polytechnic of Namibia: the quality of students, low student enrolment rates, low pass rates in science and mathematics, shortage of academic staff, dwindling government funding, and limited involvement of the mining industry. The major outcomes of this research comprise the detailed strategic actions employed by the Polytechnic of Namibia to address the threats to sustainability of its minerals education programmes.

Jan 1, 2014

By H. Hu, T. S. Golosinski

The paper reports on use of neural network algorithms to model performance and condition of mining trucks. The model inputs are selected digital data streams collected by truck Vital Information Management System, VIMS, during its operation in a mine. The models built as the result of this work allow for projection of truck condition and performance into future. As such they facilitate more efficient management of mine truck fleets. Keywords: Modelling, modeling, neural networks, mining equipment, Vital Information Management System, Intelligent Miner, mining truck

Jan 1, 2003

By S. Sarac

Solving ventilation networks of natural splitting is a basic problem in mine ventilation. Several mathematical techniques are used to solve this problem. This paper proposes a new method which combines the advantages of both classical Hardy Cross method and unconstrained optimization techniques. The trials carried out on model networks have shown that the method offers some facilities in the analysis of mine ventilation networks. Keywords: Ventilation network analysis, Hardy Cross method, Steepest Descent method.

Jan 1, 2000

Records over the past ten years indicate that there is potential for serious multiple accidents due to engulfing associated with rockpasses. Significant attention is not usually given to the design of rockpasses, with the implication that mistakes leading to poor performance of the passes are often repeated. This paper outlines general guidelines for the design, support, operation and rehabilitation of rockpasses based on information obtained from the limited amount of literature on the subject.

Jan 1, 2005

By R. P. Goel, P. N. Chaudhary, R. K. Minj

The bulk of high carbon ferromanganese produced in India continue to have more than 0.35% phosphorus since they are produced by carbothermic reduction process. The low phosphorus manganese ores are depleting fast and ferromanganese manufacturers will have no option but to use medium and low grade ores having high phosphorus content resulting in high phosphorus in the product. A systematic study was taken up at NML to solve this problem. Initially, a thermodynamic analysis was carried out for which Ba-P-O ternary predominance diagrams were constructed at several temperatures to predict the most suitable conditions for selective removal of phosphorus from high carbon ferromanganese. These conditions required a usage of a flux having a high level of basicity, moderate oxygen potential as well as low melting temperature. The experimental results showed that it was possible to remove phosphorus from high carbon liquid ferromanganese from 0.56%to 0.18% using BaCO3 based fluxes at the rate of 16-wt% of the ferromanganese charged. However, the Mn loss varied in the range of 2-5%. The objective of the subsequent study carried out at the laboratory scale was to optimize the flux consumption as well as minimize the Mn loss with effective dephosphorization by using BaO based calcined pellets instead of BaCO3 based powders. It was felt that the handling of pellets under plant conditions would be easier and also eliminate the loss of flux as a dust, which occurs when powder is added. These pellets were forced towards the bottom of the melt for better efficiency. For this purpose, a plunging system was designed and fabricated in-house that helped in reducing the flux consumption to less than 5% and also improved the kinetics of the process. The desired results were achieved within 10 minutes of the addition of the flux. The know-how is ready for transfer to interested parties and authors are willing to conduct large scale trials with them.

Jan 1, 2007

By L. Holappa

Ferroalloys like FeCr and FeMn are mostly produced in submerged electric arc furnaces. Typical for these processes is that the amount of slag is quite high. The role of slag for the process is thus very essential and specific chemical, physical and electrical properties are required. Slags in FeCr process are Al2O3-MgO-SiO2based with minor contents of CaO and CrOx. Slags in FeMn process are principally similar originating from silicate minerals but can have quite a large composition range depending on the manganese ore and its gangue minerals. Characteristic for FeMn process is that the slag is rich in manganese oxide up to above 30%. A common feature is that the ?ore oxides?, CrOx and MnOxin slag are not only divalent oxides but also containing some higher valent of Cr3+ and Mn3+, respectively. In FeMn production conditions the slag consists mainlyMn2+. This is a clear difference from CrOx containing slags in which both two and three valent coexists in slags in FeCr process conditions. Oxidation state of the slag depends on the ambient oxygen partial pressure and temperature in the examined process. Thermodynamics of slags in ferroalloys production are discussed in terms of phase diagrams, activities and oxidation state of chromium and manganese oxides. Further, slag properties influencing reduction kinetics and furnace operation i.e. viscosity and electrical resistivity are discussed. Keywords: review, slags, ferroalloys, ferrochromium, ferromanganese, thermodynamics, physical properties.

Jan 1, 2004

By W. U. Reimold, R. Armstrong, R. G. Charlesworth

For many years rockbursts have plagued the mining industry. Although much research has gone into studying this phenomenon only a small proportion of it has been on the actual source mechanism. A study was recently carried out to compliment the previous work done on the micro-structure of these features and to compare it to the micro-structures seen on shatter cones, from meteorite impacts. Both optical and electron-microscopy were used during the study. Samples were collected from rockburst sites by the CSIR Miningtek Rockburst Investigation Unit, and from the collar of the Vredefort Impact Crater. In the optical-microscopy study, the pinnate fractures observed in previous studies were seen in the shatter cones, through all the material. In the rockburst samples, the fractures were observed only in the quartz grains. Quartz micro-crystals were present in the rockburst samples and appeared to be the product of comminution rather than crystallisation. Cataclasite was present on rockburst and shatter cone fracture surfaces. The observations of the shatter cone surfaces with the scanning electron microscope are in agreement with previous work, including the observed presence of melt features, spherules and spheroidal material. The deformation in the rockburst samples is concentrated in the quartz grains, highly complicated with brittle features like sub-conchoidal structures and step structures present. A quartz spherule was identified on one rockburst sample and rhombic-dodecahedra type micro-crystals were present and seen fracturing off quartz grains. It is clear that the rockburst and shatter cone fracture surfaces are quite different; the shatter cone deformation is equally distributed across the sample and involves plastic-deformation, while the deformation in the rockburst material is concentrated in the quartz grains and, with the exception of spherule formation, is brittle. This study agreed with the current explanation for the formation of the rhombic-dodecahedra, and disproved the possibility of it being coesite or fine-grained meta-chert. Although there is no definite evidence of the mechanism of formation of the spherule, it is believed to be the product of vaporization and condensation, and the presence of this material indicates the extreme conditions under which this event occurred.

Jan 1, 2003

By F. T. Cawood

The new South African Mineral Policy has major implications on the way mineral rent will be collected and shared between the stakeholders in future. Although the policy does not supply details on how this will be done, drastic departures from practices under the previous dispensation require a new approach. For example, there introduction of the ?right to mine? principle implies that the repealed lease consideration concept will be expanded to all minerals. The new policy also makes provision for predetermined standard terms and conditions for all prospecting and mining permissions. It also states that, regardless of whether the mineral rights are state or privately-owned, all prospecting fees and mineral royalties will be determined by state officials after consultation with the registered holder of the mineral rights. This paper proposes a standard mineral royalty formula that complies with the principles mentioned in the White Paper and has been shown to be internationally competitive.

Jan 1, 2001

By T. Fabritius, L. Hekkala, J. Härkki

The Outokumpu steel belt sintering technology is used for manufacturing chromite pellets that are charged into smelting furnace for ferrochromium production. Hot air is blown through the moving bed of raw pellets. Direct temperature and flow measurements are difficult to do in the bed of a real scale belt sintering process. Therefore, a tested and reliable mathematical model would be a valuable help for optimising operational parameters of the process and designing new constructional improvements. The aim of this work is to present a mathematical model that calculates the gas flow and temperature distribution in the bed of pellets and the atmosphere. Computational fluid dynamics program FLUENT is used to calculate the gas flow, composition and temperature of the gas in the sintering bed during processing. Energy equation for the bed, containing the effects of evaporation of water and oxidation of carbon and iron oxide, will be added to the model to obtain the temperature of the pellets. The porous media model used for pressure drop calculations in the bed is shortly discussed. A comparison between CFD-calculations and experiments with a pilot scale batch-sintering reactor are also presented. The final model can be used as an engineering tool when developing the process and the equipment further. Different designs can be easily tested with the model and the effects of the changes to the flow pattern and temperature distribution can be studied.

Jan 1, 2004

By C. Musingwini

The South African mining industry continues to be a major source of employment at a time when at least 25 per cent of the working age population is unemployed. At the same time the industry faces a skills shortage in many of the disciplines necessary for its future health. The University of the Witwatersrand, University of Pretoria, University of Johannesburg, and University of South Africa have historically produced mining graduates for the South African mining industry with any shortfall being met by the recruitment of overseas graduates. More recently, the global shortage of engineers and other mining industry professionals has seen a reversal of this trend and a very significant emigration of well-educated and highly skilled personnel. The traditional career path for mining graduates is in production and mine management. However, there is the parallel (and possibly more pressing) need for specialized skills in such fields as ventilation, rock engineering, mine planning, mineral resource evaluation, and mineral asset valuation. Chronic shortages in these essential areas continue to hamper the development of the industry and may well frustrate its ambitions to be safe, healthy, and profitable into the future. The permeability of skills across sectorial boundaries within the mining industry requires that skills shortages in the platinum sector are not looked at in isolation, but within the context of the entire industry. This paper reviews the efforts being made by the universities, at both undergraduate and postgraduate levels, to meet the needs of the South African mining industry in terms of the required numbers and the range of specialized skills.

Jan 1, 2013

By K. S. Liddell, L. A. Smith

"Kell is a hydrometallurgical treatment option for the recovery of platinum group metals (PGMs), gold, silver, and base metals from flotation concentrates to refined products on site. The process is cyanidefree, while eliminating emissions of sulphur dioxide, arsenic trioxide, and other toxic species often emitted by smelters and roasters. Kell has been tested on a range of concentrates, including PGMs (UG2, Merensky, Platreef, Great Dyke, Great Lakes, Lake Superior and others), refractory gold-silver, coppergold, and polymetallic concentrates. High extraction efficiencies (>95%) are achieved for value metals (Pt, Pd, Rh, Au, Ag, Ni, Cu, Co) and secondary metals (Sb, Zn, Pb, and others). Studies comparing Kell with smelter-refining show economic benefits: capex 18–33% of smelting; opex 51–66%; electricity consumption 13–46%; and environmental benefits: greenhouse gas emissions 57–61% of smelting, acidification 5–27%, human toxicity 37–62%, and freshwater ecotoxicity 43–55% of smelting. Synergies for Kell plants alongside smelter-refineries include utilization of recovered acid from sulphur abatement systems and excess capacity in precious metal refineries. Kell is unconstrained by concentrate grade and impurities, allowing the co-location of Kell plants for treatment of non-smeltable concentrates alongside existing smelters.Kell has been demonstrated in a nine-week integrated pilot campaign at 1:1000 scale, supporting a bankable feasibility study for a 110 000 t/a plant treating a UG2-Merensky concentrate at Pilanesberg Platinum Mine (PPM), owned by Sedibelo Platinum Ltd, which has along with South African Industrial Development Corporation (IDC), invested in Kell. Zimbabwean Mining Development Corporation (ZMDC) has signed a Memorandum of Agreement (MOA) with KellTech for a centralized PGM concentrate processing plant."

Jun 1, 2019

By Simon Mundike, Muwindwa Lipalile

A scraper based block cave method has been successfully applied to extract the Lower Ore Body at Nchanga since the 1950?s. Since inception, scraper drifts and service ways have been supported using steel arch sets fabricated to a specific design from high strength manganese steel To reduce costs and to improve productivity, trials commenced in 2002 using fibre reinforced shotcrete as an alternative support method. One of the areas; the 2420 8E 1C trial drift was subjected to abutment loading for several months prior to undercutting and cave mining. Shotcrete installed exhibited minor cracking shortly after application but very little deterioration thereafter. Following the success of the trial, the application of fibre reinforced shotcrete was extended to other drifts. This paper describes the application of fibre reinforced shotcrete at Nchanga and outlines design and quality assurance methods employed.

Jan 1, 2005

By S. E. Olsen, K. Tang

Slag-metal and slag-metal-gas heterogeneous equilibria involving MnO-containing slags have been simulated using recently developed Mn-based alloy and IRSID oxide thermochemical databases. A large number of experimental equilibrium data have been used to verify the calculation results. The experimental slag-metal and slag-metal-gas equilibria in MnO-SiO2binary, MnO-SiO2-CaO and MnO-SiO2-Al2O3ternary, MnO-SiO2-CaO-Al2O3quaternary andMnO-SiO2-CaO-Al2O3-MgO higher-order system can be reproduced within experimental uncertainties. The influence of temperature, CO partial pressure and slag chemistry on the Mn-and Si-distribution equilibria have been quantitatively evaluated. This leads to a sound basis for optimizing the manganese ferroalloy production processes. Key words: MnO-containing slag, manganese ferroalloy, equilibrium simulation, thermochemical database

Jan 1, 2004