The waste products acid mine drainage formed during coal mining and fly ash from coal burning power generation, pose substantial environmental and economic problems for South Africa. Eskom has developed a remediation system employing alkaline fly ash to neutralize and precipitate heavy metals from toxic acidic acid mine drainage streams. The aim of this study was to assess the microbial diversity in and microbial impact on this remediation system.

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005.

Pulverized coal injection (PCI) technology is widely practised in blast furnace ironmaking due to economic, operational and environmental benefits. High burnout of pulverized coal in the tuyere and raceway is required for high PCI rate operation. A comprehensive review reveals that although there have been a variety of PCI models, there is still an evident need for a more realistic model for PCI operation in blast furnace. Aiming to build a comprehensive PCI model of a full-scale blast furnace, this thesis presents a series of three-dimensional mathematical models, in terms of model development, validation and application, in a sequence from a pilot-scale to a full-scale, from a simple to complicated geometry, from a coal only system to a coupled coal/coke system. Firstly a three-dimensional model of pulverized coal combustion is developed and applied to a pilot-scale PCI test rig. This model is validated against the measurements from two pilot-scale test rigs in terms of gas species composition and coal burnout. The gas-solid flow and coal combustion are simulated and analysed. The results indicate that the model is able to describe the evolutions of coal particles and provide detailed gas species distributions. It is also sensitive to various parameters and hence robust in examining various blast furnace operations. This model is then extended to examine the combustion of coal blends. The coal blend model is also validated against the experimental results for a range of coal blends conditions. The overall performance of a coal blend and the individual behaviours of its component coals are analysed. More importantly, the synergistic effect of coal blending on overall burnout is examined and the underlying mechanisms are explored. It is indicated that such synergistic effect can be optimized by adjusting the blending fraction, so as to compensate for the decreased burnout under high coal rate operation. The model provides an effective tool for the optimum design of coal blends. As a scale-up phase, the coal combustion model is applied to the blowpipe-tuyereraceway region of a full-scale blast furnace, where the raceway is simplified as a tube with a slight expansion. The in-furnace phenomena are simulated and analysed, focusing on the main coal plume. The effect of cooling gas conditions on combustion behaviours is investigated. Among the three types of cooling gas (methane, air, and oxygen), oxygen gives the highest coal burnout. Finally, a three-dimensional integrated mathematical model of pulverized coaVcoke combustion is developed. The model is applied to the blowpipe-tuyere-raceway-coke bed region of a full-scale blast furnace, which features a complicated raceway geometry and coke bed properties. The model is validated against the measurements in terms of coal burnout from a test rig and gas composition from a blast furnace, respectively. The model gives a comprehensive full-scale picture of the flow and thermo-chemical characteristics of PCI process. The typical operational parameters are then examined in terms of coal burnout and gas composition. It is indicated that the final burnout along the tuyere axis is insensitive to some operational parameters. The average burnout over the raceway surface can better represent the amount of unburnt coal particles entering the surrounding coke bed and it is also found to be more sensitive to the changes of most parameters. In addition, the underlying mechanisms of coal combustion are obtained. The coal burnout strongly depends on both oxygen availability and residence time. The existence of recirculation region gives a more realistic coal particle residence time and burnout. Compared with the fore-mentioned two models, this model is considered as a more comprehensive model of PCI operation for understanding the infurnace behaviours and provides more reliable information for the design of operational parameters.

The theme of the thesis is to investigate the current safety paradigm in the Australian coal mining industry and establish if the safety performance is improving. The number of fatalities, serious bodily injuries and high potential injuries is unsatisfactory according to community standards. People are still being killed and there is little evidence of a sustained improvement trend over the last decade. Lost time injuries have reduced dramatically, but are now plateauing and over the last few years along with high potential injuries and other safety indicators are trending upwards. This research has found that hundreds of serious injuries are not being reported which would have a significant effect on safety indicators in the Industry. Fatigue and awareness issues as well as travel times to work are having a major impact on safety at work, which is particularly evident when employees are working 12-hour shifts. The rapid expansion of the mining industry has required the growing use of contractors, hence creating a more inexperienced workforce. Another significant finding is that there is a close association between the level of fatalities recorded and the growing use of contract labour in the industry. This research has demonstrated that the current approach to prosecution is counter productive, as it inhibits thorough safety investigation and creates a defensive rather than a proactive safety culture. This approach has resulted in unwillingness by companies to examine the root causes of accidents and incidents for the fear of being prosecuted. This research has shown there is a lack of trust between mining companies, the unions and the inspectorate. It has been stated that miners lives are at risk because of the shortage of Inspectors in Queensland and that the inspectorate was not meeting its compliance obligations. There is a "disconnect" between what mining companies aspire to achieve at the corporate level with their safety management systems and what is achieved at the coal face. The thesis has demonstrated that safety performance is deteriorating and in order to improve this situation recommendations have been made regarding prosecution, contractors, fatigue, safety and health management systems, hours of work, audits and remuneration for inspectors.

Bibliography: leaves 182-190. / xv, 192 leaves [7] leaves of plates : ill., maps (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Economics, 1997

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A 2002 report by Australian National Greenhouse Gas Inventory suggests that since 1990 Australia's net emissions of carbon dioxide equivalent from stationary combustion sources are on the rise and they are likely to rise even at a higher rate in keeping with continued economic and industrial growth. In order to reduce Australian CO₂emissions, there is a need to identify and explore large-capacity storage locations for CO₂ sequestration. In that context, Australian coal seams, notably the coal-bed methane (CBM) reservoirs in Sydney and Bowen Basins, could potentially be attractive sites to sequester large volumes of greenhouse CO₂ emissions while also recovering the methane gas, a relatively cleaner source of fossil fuel. This study investigates the deliverability and economic feasibility of CO₂ sequestration through CO₂-Enhanced CBM recovery (CO₂-ECBMR) in the Camden area, Sydney coal basin. The results of the study show that the CO₂-ECBMR impacts the absolute pelmeability of the Camden area significantly. Because of a good reticulated fracture system, the CO₂ breakthrough from the producers is faster. The enhancement of CH₄ recovery by preferential adsorption of CO₂ occurs simultaneously with the abatement of CH₄ recovery by overall decrease in permeability in the CBM reservoir. Hence, the actual CH₄ is produced under the overall effect of these two competing processes, with the operating parameters like producer-injector spacing and injection pressure affecting their relative dominance over each other. The study also addresses the opportunities of a niche for CO₂ sequestration in these coals, which will be dictated mainly by the factors of sequestration economics and status of these coals being "unmineable". The results derived from the study could help the design of an optimum operating strategy in implementing the CO₂ sequestration and enhanced CBM recovery in Sydney Basin, Australia and elsewhere. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1259968 / Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2006

Title page, summary and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / Ash deposition is a problem in power generation when coal with high ash and alkali contents are utilised. The problem is more severe in fluidised bed combustion where the ash deposition can causes agglomeration of the bed material, may lead to defluidisation of the unit. The successful operation of fluid bed combustion with coal high in ash and alkali content will depend on the ability to control ash deposition. The rheological properties of coal ash under furnace conditions are important in controlling the stickiness and mobility of the molten ash deposition. Therefore, a good knowledge of the rheological properties of coal will improve the understanding of the mechanisms associated with ash deposition, and may assist in controlling the deposition and agglomeration of fluid bed material. At present, a good deal of information about coal ash rheology under conditions similar to those found in fluidised bed combustion is not known, and greater understanding is required. This is primarily due to a lack of reliable instruments and measurement techniques. In this work, a new high temperature rheometer has been developed based on the principle concepts of visco metric flow. The developed rheometer allows fundamental rheological properties, such as shear stress and shear rate, to be obtained without relying on calibrations with materials of known properties. With this instrument the flow characteristics of the tested samples can be determined directly, without assuming a particular fluid model. The new rheometer has the capability to measure the rheological properties of materials at temperatures ranging from 500°C to 1300°C and under different processing conditions. Rheological characteristics and properties of a range of low rank Australian coal ashes have been carried out using the newly developed high temperature rheometer, equipped with a cone and plate measuring geometry. It has been found that coal ash samples exhibit thixotropic and visco plastic flow behaviours. SEM and XRD analyses have revealed that during high temperature rheological measurements the coal ash sample is basically a suspension of colloidal mineral solids in a molten eutectic liquid. The solid phase is mainly silica (SiO₂,), and the liquid phase is a mixture of alkali sulphates mainly CaS0₄, MgS0₄ and Na₂S0₄ compounds. The equilibrium visco metric data of coal ash samples is found to be satisfactorily described using the Herschel-Bulkley model. The equilibrium rheological properties are strongly affected by the concentration levels of CaS0₄, MgS0₄ and Na₂S0₄ . The operating temperature and chemical composition of the surrounding gas phase were also found to affect the rheological properties of the coal ash samples. In order to obtain a better understanding and to model the rheological properties of the coal ashes, a series of synthetic ash mixtures were examined. The synthetic mixtures contained the key chemical components that represent the solid and the liquid phases. The solid phase is represented by silica (SiO₂), while a mixture of CaS0₄, MgS0₄ and Na₂S0₄ compounds represented the liquid phase. In this work, the rheological characteristics of mixtures of synthetic ash were investigated using a factorial experimental design. Using the synthetic ash mixtures together with the statistical design experiment, the effect of key chemical compounds on the rheological properties could be systematically investigated. The rheological results showed that the synthetic mixtures exhibited thixotropic and viscoplastic behaviours. It was also found that mixtures predominantly high in CaS0₄and MgS0₄ had a high degree of thixotropy behaviour, while those mixtures predominantly high in Na₂S0₄ showed a lower degree of thixotropy behaviour. The statistical analysis also showed that Na₂S0₄ is the most significant chemical compound causes a high yield stress and high viscosity. In contrast, CaS0₄and MgS0₄ were found to decrease the value of the yield stress and the viscosity. The rheological behaviour of the synthetic ash mixtures can be used to describe rheological behaviour of the coal ash samples. Relationships between equilibrium flow properties and chemical compounds, and temperatures are developed using a linear regression method. The statistical analysis has shown that CaS0₄, MgS0₄ and Na₂S0₄ , and their interactions are all significant compounds that have effects on the yield stress and viscosity of the synthetic mixtures. It was also found that the yield stress and viscosity decreased with increasing concentration level of either CaS0₄or MgS0₄ . Yield stress and viscosity are increased with increases in the concentration of Na₂S0₄ . The statistical models can successfully predict rheological properties of ash with high concentrations of CaS0₄, MgS0₄ and Na₂S0₄ , but it fails to predict the rheological properties of ashes that also high concentrations of either Fe₂0₃ or Al₂0₃, or a combination of both. The relationship between ash rheology and fluidised bed agglomeration has been established. The yield stress of a coal ash may be used to describe the tendency of the molten ash to deposit on surface of the fluid bed particles. Yield stress also determines the tendency of stickiness of the molten ash deposit to adhere the fluid bed particles during fluidised bed combustion process. The viscosity of the molten ash describes the ability of the molten ash layer to adhere the fluid bed particles after a collision. High viscosity ash tend to hold the colliding particles together longer than a low viscosity ash. Shear thinning behaviour of the ash samples (decreasing viscosity with increasing shear rate) suggests that the operating conditions could be arranged so as to minimise the chance of agglomeration. For example, in order to avoid agglomeration a high viscosity coal ash would benefit from operating the fluidised bed combustion at a high velocity, this is because a high velocity means a higher shear rate and this causes a reduction in the viscosity of the molten ash. Thus, particles agglomerated by a low viscosity ash would be easily broken by the hydrodynamic forces present during the fluidised bed process. Finally, information about ash rheology has formed a basic knowledge for estimating tendency of fluid bed agglomeration when coal obtained from different source is being used. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1141958 / Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2004

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A 2002 report by Australian National Greenhouse Gas Inventory suggests that since 1990 Australia's net emissions of carbon dioxide equivalent from stationary combustion sources are on the rise and they are likely to rise even at a higher rate in keeping with continued economic and industrial growth. In order to reduce Australian CO₂emissions, there is a need to identify and explore large-capacity storage locations for CO₂ sequestration. In that context, Australian coal seams, notably the coal-bed methane (CBM) reservoirs in Sydney and Bowen Basins, could potentially be attractive sites to sequester large volumes of greenhouse CO₂ emissions while also recovering the methane gas, a relatively cleaner source of fossil fuel. This study investigates the deliverability and economic feasibility of CO₂ sequestration through CO₂-Enhanced CBM recovery (CO₂-ECBMR) in the Camden area, Sydney coal basin. The results of the study show that the CO₂-ECBMR impacts the absolute pelmeability of the Camden area significantly. Because of a good reticulated fracture system, the CO₂ breakthrough from the producers is faster. The enhancement of CH₄ recovery by preferential adsorption of CO₂ occurs simultaneously with the abatement of CH₄ recovery by overall decrease in permeability in the CBM reservoir. Hence, the actual CH₄ is produced under the overall effect of these two competing processes, with the operating parameters like producer-injector spacing and injection pressure affecting their relative dominance over each other. The study also addresses the opportunities of a niche for CO₂ sequestration in these coals, which will be dictated mainly by the factors of sequestration economics and status of these coals being "unmineable". The results derived from the study could help the design of an optimum operating strategy in implementing the CO₂ sequestration and enhanced CBM recovery in Sydney Basin, Australia and elsewhere. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1259968 / Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2006

Title page, summary and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / Ash deposition is a problem in power generation when coal with high ash and alkali contents are utilised. The problem is more severe in fluidised bed combustion where the ash deposition can causes agglomeration of the bed material, may lead to defluidisation of the unit. The successful operation of fluid bed combustion with coal high in ash and alkali content will depend on the ability to control ash deposition. The rheological properties of coal ash under furnace conditions are important in controlling the stickiness and mobility of the molten ash deposition. Therefore, a good knowledge of the rheological properties of coal will improve the understanding of the mechanisms associated with ash deposition, and may assist in controlling the deposition and agglomeration of fluid bed material. At present, a good deal of information about coal ash rheology under conditions similar to those found in fluidised bed combustion is not known, and greater understanding is required. This is primarily due to a lack of reliable instruments and measurement techniques. In this work, a new high temperature rheometer has been developed based on the principle concepts of visco metric flow. The developed rheometer allows fundamental rheological properties, such as shear stress and shear rate, to be obtained without relying on calibrations with materials of known properties. With this instrument the flow characteristics of the tested samples can be determined directly, without assuming a particular fluid model. The new rheometer has the capability to measure the rheological properties of materials at temperatures ranging from 500°C to 1300°C and under different processing conditions. Rheological characteristics and properties of a range of low rank Australian coal ashes have been carried out using the newly developed high temperature rheometer, equipped with a cone and plate measuring geometry. It has been found that coal ash samples exhibit thixotropic and visco plastic flow behaviours. SEM and XRD analyses have revealed that during high temperature rheological measurements the coal ash sample is basically a suspension of colloidal mineral solids in a molten eutectic liquid. The solid phase is mainly silica (SiO₂,), and the liquid phase is a mixture of alkali sulphates mainly CaS0₄, MgS0₄ and Na₂S0₄ compounds. The equilibrium visco metric data of coal ash samples is found to be satisfactorily described using the Herschel-Bulkley model. The equilibrium rheological properties are strongly affected by the concentration levels of CaS0₄, MgS0₄ and Na₂S0₄ . The operating temperature and chemical composition of the surrounding gas phase were also found to affect the rheological properties of the coal ash samples. In order to obtain a better understanding and to model the rheological properties of the coal ashes, a series of synthetic ash mixtures were examined. The synthetic mixtures contained the key chemical components that represent the solid and the liquid phases. The solid phase is represented by silica (SiO₂), while a mixture of CaS0₄, MgS0₄ and Na₂S0₄ compounds represented the liquid phase. In this work, the rheological characteristics of mixtures of synthetic ash were investigated using a factorial experimental design. Using the synthetic ash mixtures together with the statistical design experiment, the effect of key chemical compounds on the rheological properties could be systematically investigated. The rheological results showed that the synthetic mixtures exhibited thixotropic and viscoplastic behaviours. It was also found that mixtures predominantly high in CaS0₄and MgS0₄ had a high degree of thixotropy behaviour, while those mixtures predominantly high in Na₂S0₄ showed a lower degree of thixotropy behaviour. The statistical analysis also showed that Na₂S0₄ is the most significant chemical compound causes a high yield stress and high viscosity. In contrast, CaS0₄and MgS0₄ were found to decrease the value of the yield stress and the viscosity. The rheological behaviour of the synthetic ash mixtures can be used to describe rheological behaviour of the coal ash samples. Relationships between equilibrium flow properties and chemical compounds, and temperatures are developed using a linear regression method. The statistical analysis has shown that CaS0₄, MgS0₄ and Na₂S0₄ , and their interactions are all significant compounds that have effects on the yield stress and viscosity of the synthetic mixtures. It was also found that the yield stress and viscosity decreased with increasing concentration level of either CaS0₄or MgS0₄ . Yield stress and viscosity are increased with increases in the concentration of Na₂S0₄ . The statistical models can successfully predict rheological properties of ash with high concentrations of CaS0₄, MgS0₄ and Na₂S0₄ , but it fails to predict the rheological properties of ashes that also high concentrations of either Fe₂0₃ or Al₂0₃, or a combination of both. The relationship between ash rheology and fluidised bed agglomeration has been established. The yield stress of a coal ash may be used to describe the tendency of the molten ash to deposit on surface of the fluid bed particles. Yield stress also determines the tendency of stickiness of the molten ash deposit to adhere the fluid bed particles during fluidised bed combustion process. The viscosity of the molten ash describes the ability of the molten ash layer to adhere the fluid bed particles after a collision. High viscosity ash tend to hold the colliding particles together longer than a low viscosity ash. Shear thinning behaviour of the ash samples (decreasing viscosity with increasing shear rate) suggests that the operating conditions could be arranged so as to minimise the chance of agglomeration. For example, in order to avoid agglomeration a high viscosity coal ash would benefit from operating the fluidised bed combustion at a high velocity, this is because a high velocity means a higher shear rate and this causes a reduction in the viscosity of the molten ash. Thus, particles agglomerated by a low viscosity ash would be easily broken by the hydrodynamic forces present during the fluidised bed process. Finally, information about ash rheology has formed a basic knowledge for estimating tendency of fluid bed agglomeration when coal obtained from different source is being used. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1141958 / Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2004

Acid rock drainage (ARD) is recognised as one of the most serious environmental issues currently facing the mining industry. ARD management strategies rely heavily on the ability to measure the ARD potential of waste materials to ensure strategies are appropriate to the ARD risks. It is apparent that improvements to the understanding of ARD test methods and development of methods to better represent the ARD potential of samples will contribute significantly to the value and reliability of ARD assessment. The research described in this thesis focused on critical assessment and improvement of: ARD test methodology; approach to testing; and interpretation of results for coal mine wastes. Kaltim Prima Coal Mine (KPC) in Kalimantan, Indonesia was selected as a case study site to help focus the research, with the understanding that the broad similarities of coal sequences in general would allow broader application of the findings. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005