A research report submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering (Mining) to the faculty of engineering and the built environment, University of the Witwatersrand, Johannesburg Date of final submission 25 May 2017 / The Australasian code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, of the Joint Ore Reserves Committee (JORC) sets out minimum standards, recommendations and guidelines for Public Reporting in Australasia. (JORC, (2012)). The Committee for Mineral Reserve International Reporting Standards (CRIRSCO) created a set of standard international definitions for reporting Mineral Resources and Mineral Reserves based on the evolving JORC code’s definitions (CRIRSCO, (2013)). CRIRSCO’s members are National Reporting Organisations (NRO’s) which are responsible for developing mineral reporting codes for Australia (JORC), Canada (CIM Standing Committee on Reserve Definitions), Chile (National Committee), Europe (PERC), Russia (NAEN), South Africa (SAMCODES) and USA (SME) (JORC, (2012)). The NRO’s for; South Africa (SAMREC), Australia (JORC) and Canada (CIM Standing Committee on Reserve Definitions) published supporting standards for Coal Resource and Reserve Classification and Reporting namely, South African National Standard: South African Guide to the Systematic Evaluation of Coal Resources and Coal Reserves (SANS10320:2004), the Australian Guidelines for the Estimation and Classification of Coal Resources (Australian Guidelines (2014)) and the GSC Paper 88-21: A Standardized Coal Resource/Reserve Reporting System for Canada (Hughes, et al., (1989)). With the objective to identify the most appropriate Coal Resource Classification approach for the Witbank Coalfields in South Africa, Coal Resource Classification methods applied elsewhere in the world were investigated, these countries include Canada and Australia. SANS10320:2004 relies on a minimum drillhole spacing dependant on two different coal seam deposit types, whereas the Australian Guideline for the Estimation and Classification of Coal Resources (2014) provide a guide as to which geological aspects need to be considered when classifying a coal deposit into the appropriate confidence category, and no fixed drillhole spacing is recommended. The Canadian Standardized Coal Resource/Reserve Reporting System (1989) differs from the afore mentioned standards in that it is a prescriptive method based on specific levels of geological complexity, governed by specific fixed parameters. None of the other Coal Reporting codes/standards use a broad sweeping fixed drillhole spacing to classify Coal Resources as in South Africa. It is noted from experience as well as by Coal Resource Classification methods used elsewhere in the world that the use of proposed fixed drillhole spacing, such as currently in use in SANS10320:2004, is an unsatisfactory method for assessing the uncertainty and variability associated with coal deposits. The Coal Resource Classification methodologies utilised on a local scale in South Africa, were investigated to establish how mining houses manage and assess the variability in their Coal Resources. Fourteen mines operating throughout the Witbank coalfield were compared, it was found that although the Coal Resource Classification of the governing code requires a 350m drillhole spacing for highest level of confidence, the mines drill to a much smaller grid for increased confidence. Despite this, the mines still report on the SANS10320:2004 minimum standard in the public domain. A map was created based on the average drillhole spacing drilled per mine. From this it was deduced that there are zones of higher coal seam variability which required a closer spaced drilling grid to derive sufficient geological confidence in the estimates. Based on these deductions four zones of comparable continuity/variability, were identified. The zones identified by means of geological investigation and those identified by differences in variability as perceived by the Competent Person (CP) correlate. The highest variability and smallest drillhole spacing is located toward the western portion of the coalfield whereas the lowest variability with the largest drillhole spacing is located toward the east. The geologically complex Witbank coalfield was divided into four geo-zones/domains based on the depositional environment, basement rocks and post depositional influences. It is evident that a suitable Coal Resource Classification approach; which considers the characteristics of the geozones are followed. The question of which other classification methods are appropriate if not a predetermined drillhole spacing is addressed by this research. Statistics on relevant variables can provide a measure of uncertainty and therefore reliability in the estimates, for this reason three methods of uncertainty and probability characterisation were investigated. Of the three, namely; Non-linear estimation approach, conditional simulation (CS) and global estimation variance (GEV), the latter was deemed the most appropriate. GEV forms the basis of Drillhole Spacing Analysis (DHSA) and was applied to a mid-sized coal mine within the western portion of the Witbank coalfield. The analysis did not result in robust Coal Resource classification of estimates but rather provided more insight into the variability of the deposit. The results of DHSA are easily manipulated and are open for interpretation, it is therefore suggested as a valuable exercise/tool for understanding and assessing coal seam variability and to be used as a guide in Coal Resource classification. Onsite practical geological information should not be underestimated and geostatistics should always confirm the geology. A purely mathematical approach to Coal Resource classification would be a gross oversight, a combination of geological factors in association with statistical inferences is suggested. A scorecard method with associated weights is proposed to improve the confidence in the Coal Resource classification. / MT 2017

The Fluidised Bed Combustion (FBC) technology has been widely used internationally for power generation. This technology has good fuel flexibility and reduced S02 emissions with dry sorbent (Limestone or Dolomite) addition. South Africa has large reserves of coals that are difficult to combust in conventional pulverised fuel fired boilers. These reserves could be potential feedstocks for new build FBC boilers. The chemical composition of these coals is site specific and could have an impact on the combustion performance of the fuel. This necessitates the need for FBC coal tests in the presence of a sorbent. The objectives of this study were to investigate the changes in the production NO" SO" and the combustion efficiency of the three test coals under conditions of fluidised bed combustion, with the same sorbent. Tests with no sorbent were performed to evaluate the coals inherent calcium capabilities of capturing sulphur. Tests with varying ratios of sorbent were performed to evaluate the sorbent's capabilities for further levels of in-bed desulphurisation. The experimental equipment used in this investigation was the Eskom Fluidised Bed Test Facility (FBTF). This facility is a bubbling fluidised bed combustorlgasifier. The investigated bed temperature range was between 800 to 900°C, in intervals of 20°C. The operating pressure was 50kPa (gauge). The three coals were compared at CalS molar ratio of 1. Carbon in ash has shown to decrease with an increase in bed temperature for Coal A, Band C. The best performing coal in terms of least quantity of remaining carbon in ash was Coal A. The NO emissions increased for an increase in bed temperature for Coal A, Band C. The greatest NO emissions were recorded during Coal B tests. The N 20 emissions decreased with an increase in bed temperature for Coal A and B tests. Higher N 20 emissions were observed for Coal B than Coal A tests. In terms of S02 retention Coal C performed the best. The optimal operating bed temperature for S02 retention observed for the three coals was in the region of 800-860°C. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.

The aim of this project was to identify and assess all possible solutions to reduce carbon dioxide (CO2) emissions from coal power plants in South Africa, identify the most likely solution to be implemented industrially in the short to mid-term future, and contribute towards its development through lab measurement and further research. This thesis thus contains a substantial literature review conducted on the current state of CO2 emissions in South Africa, conventional and novel coal power plant processes, modes of CO2 capture, criteria regarding the implementation of CO2 capture techniques, and the various CO2 capture techniques currently investigated with varying levels of development. The study found gas absorption using solvents to be the most likely mid-term CO2 capture technique to reach industrial implementation. However, certain challenges still need to be overcome, particularly due to numerous limitations of current solvents, to make this technique feasible for CO2 capture. In an attempt to overcome the main challenge of solvent absorption capacity, it was decided to investigate the use of ionic liquids for CO2 absorption. An in-depth review of ionic liquids was conducted, as well as a review of measurement techniques and modelling of gas absorption in alkanolamine and ionic liquid solvents. Four ionic liquids, namely methyl trioctyl ammonium bis(trifluoromethylsulfonyl)imide [MOA][Tf2N], 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide [Bmim][Tf2N], 1-butyl-3-methyl imidazolium tetrafluoroborate [Bmim][BF4], and 1-butyl-3-methyl imidazolium methyl sulphate [Bmim][MeSO4] were tested for CO2 and O2 absorption by measuring equilibrium Pressure-Temperature-Liquid mole fraction (P-T-x) data. Measurements were conducted using an Intelligent Gravimetric Analyser (IGA-01) at 303.15, 313.15, and 323.15 K. CO2 partial pressures of 0.05 to 1.5 MPa and O2 partial pressures of 0.05 to 0.7 MPa were investigated. Furthermore, density and refractive index measurements were conducted for all solvents. The ionic liquids were benchmarked against other ionic liquids and conventional alkanolamine solvents for CO2 absorption capacity and selectivity. The study found that ionic liquids achieved higher CO2 absorption capacity at high pressure than conventional alkanolamine solvents, but very low absorption capacity at low pressure. Of the ionic liquids studied, [Bmim][BF4] and [Bmim][Tf2N] achieved high CO2 absorption and high CO2 selectivity over O2. Therefore, these two ionic liquids were selected to be combined with conventional alkanolamine solvents, namely Monoethanolamine (MEA), Diethanolamine (DEA), and Methyl Diethanolamine (MDEA), in order to form hybrid solvents. P-T-x data was obtained for CO2 absorption in alkanolamine-ionic liquid hybrid solvents containing various compositions of the above alkanolamines and ionic liquids, by gravimetric analysis, under temperature and pressure conditions as described above. CO2 absorption in the hybrid solvents was analysed, compared, and benchmarked against absorption in pure ionic liquids and conventional alkanolamine solvents. Absorption data for pure ionic liquid systems was modelled using the Redlich-Kwong equation of state (RK-EOS), while absorption in hybrid solvents was modelled using the RK-EOS for the ionic liquid components and the Posey-Tapperson-Rochelle model for the alkanolamine components of each hybrid solvent. All modelling was programmed using MatlabTM R2012B engineering programming software. Further composition analysis was intended using Fourier transform infrared (FTIR) spectroscopy. The design and development of this apparatus is described herein. The apparatus possessed limitations in achieving the desired measurements. Recommendations are described for future modifications to make the apparatus more applicable for the systems in this work. The most important conclusion was that the hybrid solvents successfully achieved higher equilibrium CO2 absorption than conventional alkanolamine solvents and pure ionic liquids, at low pressure. Absorption increased with higher temperature, lower pressure, and alkanolamine concentrations lower than 40wt%. Modelling of CO2 absorption in hybrid solvents using the above stated model proved inadequate, with deviations nearly as high as 10% of measured data. A process of CO2 capture was simulated using the engineering software Aspen Plus V8.0. CO2 absorption in the hybrid solvent containing MEA:DEA:[Bmim][BF4] at 31.8:12.1:56.1 wt% was benchmarked against CO2 absorption in a conventional alkanolamine solvent. The simulation revealed a significant improvement in CO2 absorption using the hybrid solvent at low system pressure. However CO2 selectivity and solvent recycle heat duty results were undesirable. Finally, recommendations are listed for future research endeavours, simulation and apparatus development. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

M.Sc. / Please refer to full text to view abstract

Bibliography: pages 116-119. / In South Africa, ever increasing quantities of fine (-0,5 mm) coal are being produced as a result of the increased use of mechanised mining methods. Very few mines beneficiate the fines; in most cases they are discarded. However the fine size of this material suggests that it should be well liberated, with the potential to produce a low ash product. This thesis forms part of an ongoing research program examining the use of flotation to beneficiate coal fines to produce a low ash product. Coal is a highly heterogeneous material, consisting of a number of both organic (maceral) and inorganic (mineral) components with different physical and technological properties. Therefore in order to evaluate and interpret flotation results, an understanding of the liberation characterist ics of both the organic and inoganic components is required. This thesis presents a liberation study on fine coal from the Greenside Colliery, a typical colliery in the Witbank Coalfield which is the most important source of South African low ash coal. The study was performed by mining a run of mine coal sample to varying degrees of fineness (from 30 % finer than 150 micron to 90 % finer than 150 micron), screening, and assessing the liberation of each size fraction. These results were compared to those obtained from a sample of naturally arising fines (thickener underflow). Liberation was assessed by float and sink analysis, and for this purpose a new technique was developed that enables rapid and accurate float and sink analysis of coal down to a few micron in size. Petrographic analyses were performed to determine the liberation of the organic coal components.

M.Phil. / Coal is today providing more than seventy-five percent of South Africa's energy requirements and will, to a large extent, remain so in the future. It is thus important to evaluate the adequacy of the country's available coal resources against expected future demand. The main objective of this study, which was done under the supervision of Prof. D. J. Kotze, was therefore to analyse the specific consumption of coal in the various consumption sectors in order to establish historical trends. The specific comsumption of coal is defined as the amount of coal used to produce a unit of final product. The factors attributing to these observed trends were determined and their future role evaluated in order to establish whether it was possible to extrapolate historical trends into the future. By means of curve fitting to the observed data and extrapolation it was possible to obtain future values of specific coal consumption for each of the sectors. These values, together with the production output forecasts for the various sectors were then used to calculate the total coal requirements for three reference years, namely, 1990, 1995 and 2000. The role of coal prices in explaining trends in specific coal consumption of various sectors was also analised separately. Information to conduct the study was obtained mainly from the various coal producers' associations as well as from individual producers and other organizations such as Escom, Sasol and Iscor, the Department of Hineral and Energy Affairs and the Hinerals Bureau. In some instances private firms and producers' associations were also consulted as well as a wide variety of literature on the subject. The principal finding of the study was that coal was substituted or was still being substituted by electricity in most final applications because of the convenience of use. Coal, however, still plays and probably will continue to play an important role in future in basic industries such as the metallurgical industry. Coal prices have not up to now played a very important role in the overall specific consumption of coal which can probably be attributed to the relatively low prices of coal on the inland market. It was also found that it was not desirable to do away with the present system of price control entirely as a certain measure of control was still necessary to safeguard the usuage of coal in certain applications for which there were no other substitutes. It was further concluded that South Africa does not have the vast quantities of coal commonly thought and that measures have to be taken in order to ensure that the country's coal resources are conserved and that optimum use is made of available resources.

M.Phil. (Energy Studies) / Please refer to full text to view abstract

Thesis (MBA)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Severe flooding in Queensland, Australia in late 2010 and into February of 2011 resulted in significant losses to infrastructure, equipment and coal production. Xstrata Coal (XC) mines suffered billions of dollars worth of losses, resulting in insurance premiums increasing drastically in subsequent months. These events prompted Xstrata‟s top management to reconsider the way in which they managed risk. Initial revelations were that the focus of Risk Management had largely been on the areas of Health and Safety and that, particularly in South Africa, the outcome of all management‟s efforts to manage risk had been to comply with the relevant legislation. There was clearly an attempt to avoid litigation resulting in potential prosecution. The most stringent of this legislation was that of the Mine Health and Safety Act (No. 24 of 996), as promulgated by the Department of Mineral Resources. The requirements were prescriptive to the extent that mine management was required to utilise the Hazard Identification Risk Assessment process to identify hazards, assess the associated risk and apply mitigation, largely in order to prevent incidents which could affect the health and safety of employees. Little regard was given to the fact that mining houses could endure severe financial losses as a result of catastrophic events, which could stop production for significant periods of time. Whilst Xstrata did recognise Business Continuity Risk (BCR), the risk assessment process which was introduced along with the CURA risk register displayed a distinct division between Health and Safety Risk and BCR. Furthermore, this was not a systematic process. Initial risk categories were prescribed by XC mainly based on experiences in Australia. The floods prompted a rethink and Xstrata‟s prescription to conduct business continuity risk assessments (BCRAs) coincided perfectly with this writer‟s exposure to the Enterprise Risk Management Elective at the University of Stellenbosch‟s Business School. As the General Manager of the iMpunzi Complex that comprises three coalmines, it was the responsibility of the writer to carry out the instruction to review the business continuity process. Consequently, the research is intended to assess the current Risk Management environment within Xstrata Coal South Africa by means of an analysis of current documentation and interviews with select key personnel who largely influence and impact the management of risk in the company. Thereafter, the study will progress to the methodology involved in the Risk Assessments, followed by an assessment of the knowledge, skills and qualifications required for the relevant, accountable managers appointed to manage the risks. The findings of the research were that whilst there was quite a rigid framework, which was aligned with ISO 31000 principles for risk management, there were shortcomings in the methodology of the risk assessment process, as well as the considerations for dealing with latent or residual risk. To this extent, the writer recommended: A risk assessment template which prescribes, but is not limited to, the hazards which may be prevalent on a coal mine, including hazards specific to iMpunzi Complex; A revised template for the Risk Treatment Plan, which takes cognisance of Residual Risk; Other recommendations, which may deal with minor findings of the study.

M.Phil. / The study was undertaken at Bosjesspruit, one of the Sasol Collieries, to investigate aspects that contribute to the degradation of coal. Bosjesspruit is penalised with more than nine million rands per year for fine coal that exceeds the set limits. Compliance to quality is the main reason. The cost is directly deducted from the profit. The quality of coal is of importance for the effectiveness of the gasifying process. A feasibility study has indicated that this study is viable. Various factors in the process were studied to identify the system deviations such as: coal bunkers, section and main conveyor belts, geology, production section activities and coal production equipment. A literature study was done and time was spent to become conversant with the coal transport system. The process is described from where the coal is mined, through the handling action up to where it is fed into the Sasol plant gasifiers. Several coal samples of the identified bottleneck areas were taken and analysed. The four main areas that were studied are: Loading actions at East 700 bunker. Incline shaft transfer chute. The horizontal bunker on surface. The South section conveyor chutes. The free-flow technology was researched and developed for an acceptable chute design. The design is now computerised and in use at Sasol Collieries. The current design and its restrictions are compared with the proposed designs to indicate the improvements. A detailed cost analysis was done to determine the expenditures such as: Penalties for fine coal. The cost of adaptability and redesign. - Forecast cost savings after the redesigns are implemented. - Cost to produce coal as well as the income for Bosjesspruit. An economical evaluation indicates that all the suggested solutions are economically justifiable. The results of the study indicate several suggested solutions to overcome the identified bottlenecks. It is further suggested that results of this study are also implemented at the other Sasol mines as well as the mines that are being developed.

Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Xstrata Coal South Africa (XCSA) embarked on a restructuring exercise towards the end of 2005 to enable the organisation and its management to adapt to the pressures and requirements of an ever-changing South African coal industry. The executive team of XCSA felt that some of the business units were too large to be effectively managed by one general manager and his/her management team. The Tweefontein and Impunzi business units fell into this category. Further, the executive team felt that the existing organisational structures on the mines were unable to effectively manage the demands coming from an ever-changing coal industry. Most such demands emanated from sustainable development issues: workplace safety, environmental management, health-related concerns to do with the employees and community development around the mines. The restructuring took place towards the end of 2005, not long after the restructuring of the business performance went into decline. The author of this thesis, as the General Manager of the Tweefontein Complex from the beginning of 2006 until mid-2008, was responsible for the day-to-day management of the division at the time. After explaining the need for restructuring, as well as how the structure was changed, the author will describe a comprehensive literature research study. The aim of such a study is to create a common understanding with the reader of the principles relating to culture, leadership and change management. The author then compares the two climate assessments of the organisational culture of the Boschmans Colliery undertaken during 2005 prior to embarking on the restructuring exercise, and of the Tweefontein Complex undertaken during 2007, on completion of the restructuring. Boschmans Colliery employees now constitute most of the underground and surface operations areas of the Tweefontein Complex. The organisational culture of the Tweefontein Complex was found to have been influenced by the restructuring exercise. The author concludes with recommendations on how the organisational culture of XCSA as a whole could be aligned. Chief among the recommendations are that: • A cultural alignment programme should be implemented to create a common organisational culture across XCSA. • A leadership development programme should be implemented to promote the desired organisational culture. • A communication strategy should be implemented to support the cultural alignment programme. • A branding campaign should be launched to strengthen the image of XCSA within the surrounding community. / AFRIKAANSE OPSOMMING: Xstrata Coal South Africa (XCSA) het aan die einde van 2005 besluit om die besigheid te herstruktureer om aan te pas by die veranderende aard van die Suid-Afrikaanse steenkoolindustrie. Die gevoel van die uitvoerende komitee was dat sekere van die besigheidseenhede te groot was om effektief deur een algemene bestuurder, bestuur te word. Die Tweefontein- en Impunzi-besigheidseenhede het in die kategorie geval. Verder het die uitvoerende kommitee gevoel dat die bestaande bestuurstruktuur per myn nie voldoende was om al die verwagtinge vanuit 'n vinnig veranderende steenkoolindustrie effektief te kan bestuur nie. Die vernaamste verwagtinge van die vinnig veranderende industrie was die vanuit die veld van Volhoubaarheid, naamlik veiligheid op myne, omgewingsbewustheid, gesondheid van die werknemers, sowel as die opbou van die gemeenskap. Die herstrukturering het aan die einde van 2005 plaasgevind en nie lank na die herstrukturering nie het die prestasie van die besigheid drasties afgeneem. Die skrywer was die Algemene Bestuurder van die Tweefontein Complex vanaf die begin van 2006 tot die middel van 2008, en was verantwoordelik vir die dag-tot-dag-bestuur van die afdeling. As deel van die studie sal die skrywer eerstens poog om die redes vir die herstrukturering te gee en ook hoe die nuwe struktuur daar uitsien. Tweedens sal die skrywer 'n deeglike literatuurstudie verskaf om 'n gemeenskaplike verstandhouding tussen die skrywer en die leser oor die beginsels van kultuur, leierskap en veranderingsbestuur te skep. Derdens sal die skrywer die resultate van twee klimaatstudies ontleed wat op die besigheidskultuur van die Boschmans-steenkoolmyn in 2005 voor die herstrukturering gedoen is en een wat in 2007 op die Tweefontein Complex na die herstrukturering gedoen is. Die werknemers van die Boschmans-steenkoolmyn maak tans die grootste gedeelte van die Tweefontein Complex se ondergrondse en aanleg- en logistieke afdelings uit. Na aanleiding van die analise van die twee klimaatstudies, bevind die skrywer dat die herstrukturering 'n daadwerklike invloed op die kultuur van die Tweefontein Complex gehad het. Die skrywer maak dan na gelang van sy bevindinge aanbevelings oor hoe die kultuur van Xstrata Coal South Africa (XCSA) as 'n geheel belyn kan word. Sy belangrikste aanbevelings is as volg: • Die implementering van 'n kultuurbelyningsprogram om 'n gemeenskaplike besigheidskultuur regoor Xstrata Coal South Africa (XCSA) daar te stel. • Die implementering van 'n leierskapsontwikkelingsprogram wat belyn is met die verlangde besigheidskultuur. • Die implementering van 'n kommunikasiestrategie wat die kultuurbelyningsprogram ondersteun. • Die loodsing van 'n Xstrata Coal South Africa (XCSA) bemarkingsveldtog am Xstrata Coal se beeld in die gemeenskap te bevorder.