Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The middle eocene to early oligocene Bowmans and Lochiel coal deposits of the northern St. Vincent Basin, South Australia have been studied to elucidate their depositional environments. These coals occur within predominantly fluvio-lacustrine transgressive system tract sequences that formed during the initial phase of basin infill. The aforementioned facies are unevenly distributed and their stratigraphic succession highlights evolutionary changes in local palaeoenvironments. Within individual seams the transition from subaquatic to topogenous forest swamps and ultimately ombrogenous conditions is most common. However, over the coal sequence as a whole, conditions evolved from exclusively terrestrial through mixed terrestrial and subaquatic to open water. Also detected were multiple rapid reversals of the water table, especially higher in the sequence, and cyclic patterns reflecting a brief basal subaquatic phase prior to the onset of sustained terrestrial conditions. These patterns suggest a fluctuating, although progressively rising, water table and a balance between accommodation and accumulation. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280880 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Depósitos de rejeitos de carvão proporcionam uma série de problemas ambientais, pois ocupam uma grande área física, modificam o relevo, a paisagem e geram a drenagem ácida de minas (DAM). Assim, o objetivo do presente trabalho foi realizar a caracterização do material em um depósito de rejeitos da Carbonífera Criciúma S/A, de forma a avaliar a possibilidade de separação de três frações para futura reutilização: (a) uma fração de densidade baixa, rica em carvão para uso energético; (b) uma fração de densidade intermediária, com predomínio de materiais inertes; (c) uma fração de densidade alta, para uso comercial da pirita. A metodologia do trabalho consistiu na coleta de amostras e caracterização do material. A caracterização incluiu a análise granulométrica, estudos de afunda-flutua em meios densos e análises do material em termos de teor de cinzas e enxofre total. Os resultados demonstraram que 68% do material apresentam granulometria grosseira (entre 50,8 mm e 2,0 mm), 15% granulometria fina (entre 2,0 e 0,1 mm) e que 17% correspondem ao lodo proveniente das bacias de decantação. Os estudos indicam que é possível, por beneficiamento gravimétrico, recuperar 37% do material para fins energéticos, com um teor de 67,0% de cinzas e 2,9% de enxofre total. Ainda, 10% do material poderá ser recuperados para obtenção de um concentrado rico em pirita. O material remanescente, com densidade intermediária, poderá ser disposto com um menor potencial de geração de acidez. / Coal tailing deposits can be a source of various environmental problems. It demands large physical area, change the topography and generate the acid mine drainage (AMD). The aim of this work was to characterize the coal tailing deposit of Carbonífera Criciúma S/A, seeking the separation of three fractions for future reuse: (a) a fraction of low density for energy production in thermoelectric plants, (b) a fraction of intermediate density, with predominance of inert minerals, and (c) a fraction of high density, for commercial use of pyrite. The work methodology consisted in sample collection and characterization of the material. The characterization included particle size analysis, densimetric studies and material analyses in terms of ash and total sulfur. The results showed that 68% of the material is composed by coarse particles (between 50.8 mm and 2.0 mm), and 15% of fine particles (between 2.0 and 0.1 mm) and 17% sludge from settling ponds. It is possible, by gravimetric concentration, to recover 34.2% of the material for energetic application, with 67.0% ash and 2.9% sulfur. Still, 10.0% of the material can be recovered as a pyrite rich concentrate. The remaining material, with intermediate density, can be discarded with a lower acid generation potential.

Depósitos de rejeitos de carvão proporcionam uma série de problemas ambientais, pois ocupam uma grande área física, modificam o relevo, a paisagem e geram a drenagem ácida de minas (DAM). Assim, o objetivo do presente trabalho foi realizar a caracterização do material em um depósito de rejeitos da Carbonífera Criciúma S/A, de forma a avaliar a possibilidade de separação de três frações para futura reutilização: (a) uma fração de densidade baixa, rica em carvão para uso energético; (b) uma fração de densidade intermediária, com predomínio de materiais inertes; (c) uma fração de densidade alta, para uso comercial da pirita. A metodologia do trabalho consistiu na coleta de amostras e caracterização do material. A caracterização incluiu a análise granulométrica, estudos de afunda-flutua em meios densos e análises do material em termos de teor de cinzas e enxofre total. Os resultados demonstraram que 68% do material apresentam granulometria grosseira (entre 50,8 mm e 2,0 mm), 15% granulometria fina (entre 2,0 e 0,1 mm) e que 17% correspondem ao lodo proveniente das bacias de decantação. Os estudos indicam que é possível, por beneficiamento gravimétrico, recuperar 37% do material para fins energéticos, com um teor de 67,0% de cinzas e 2,9% de enxofre total. Ainda, 10% do material poderá ser recuperados para obtenção de um concentrado rico em pirita. O material remanescente, com densidade intermediária, poderá ser disposto com um menor potencial de geração de acidez. / Coal tailing deposits can be a source of various environmental problems. It demands large physical area, change the topography and generate the acid mine drainage (AMD). The aim of this work was to characterize the coal tailing deposit of Carbonífera Criciúma S/A, seeking the separation of three fractions for future reuse: (a) a fraction of low density for energy production in thermoelectric plants, (b) a fraction of intermediate density, with predominance of inert minerals, and (c) a fraction of high density, for commercial use of pyrite. The work methodology consisted in sample collection and characterization of the material. The characterization included particle size analysis, densimetric studies and material analyses in terms of ash and total sulfur. The results showed that 68% of the material is composed by coarse particles (between 50.8 mm and 2.0 mm), and 15% of fine particles (between 2.0 and 0.1 mm) and 17% sludge from settling ponds. It is possible, by gravimetric concentration, to recover 34.2% of the material for energetic application, with 67.0% ash and 2.9% sulfur. Still, 10.0% of the material can be recovered as a pyrite rich concentrate. The remaining material, with intermediate density, can be discarded with a lower acid generation potential.

Depósitos de rejeitos de carvão proporcionam uma série de problemas ambientais, pois ocupam uma grande área física, modificam o relevo, a paisagem e geram a drenagem ácida de minas (DAM). Assim, o objetivo do presente trabalho foi realizar a caracterização do material em um depósito de rejeitos da Carbonífera Criciúma S/A, de forma a avaliar a possibilidade de separação de três frações para futura reutilização: (a) uma fração de densidade baixa, rica em carvão para uso energético; (b) uma fração de densidade intermediária, com predomínio de materiais inertes; (c) uma fração de densidade alta, para uso comercial da pirita. A metodologia do trabalho consistiu na coleta de amostras e caracterização do material. A caracterização incluiu a análise granulométrica, estudos de afunda-flutua em meios densos e análises do material em termos de teor de cinzas e enxofre total. Os resultados demonstraram que 68% do material apresentam granulometria grosseira (entre 50,8 mm e 2,0 mm), 15% granulometria fina (entre 2,0 e 0,1 mm) e que 17% correspondem ao lodo proveniente das bacias de decantação. Os estudos indicam que é possível, por beneficiamento gravimétrico, recuperar 37% do material para fins energéticos, com um teor de 67,0% de cinzas e 2,9% de enxofre total. Ainda, 10% do material poderá ser recuperados para obtenção de um concentrado rico em pirita. O material remanescente, com densidade intermediária, poderá ser disposto com um menor potencial de geração de acidez. / Coal tailing deposits can be a source of various environmental problems. It demands large physical area, change the topography and generate the acid mine drainage (AMD). The aim of this work was to characterize the coal tailing deposit of Carbonífera Criciúma S/A, seeking the separation of three fractions for future reuse: (a) a fraction of low density for energy production in thermoelectric plants, (b) a fraction of intermediate density, with predominance of inert minerals, and (c) a fraction of high density, for commercial use of pyrite. The work methodology consisted in sample collection and characterization of the material. The characterization included particle size analysis, densimetric studies and material analyses in terms of ash and total sulfur. The results showed that 68% of the material is composed by coarse particles (between 50.8 mm and 2.0 mm), and 15% of fine particles (between 2.0 and 0.1 mm) and 17% sludge from settling ponds. It is possible, by gravimetric concentration, to recover 34.2% of the material for energetic application, with 67.0% ash and 2.9% sulfur. Still, 10.0% of the material can be recovered as a pyrite rich concentrate. The remaining material, with intermediate density, can be discarded with a lower acid generation potential.

The operational scheduling at coal handling facilities is of the utmost importance to ensure that the coal consuming processes are supplied with a constant feed of good quality coal. Although the Sasol Coal Handling Facility (CHF) were not designed to perform coal blending during the coal handling process, CHF has to blend the different sources to ensure that the quality of the feed supplied is of a stable nature. As a result, the operation of the plant has become an extremely complex process. Consequently, human intelligence is no longer sufficient to perform coal handling scheduling and therefore a scheduling model is required to ensure optimal plant operation and optimal downstream process performance. After various attempts to solve the scheduling model optimally, i.e. with exact solution methods, it was found that it is not possible to accurately model the complexities of CHF in such a way that the currently available exact solvers can solve it in an acceptable operational time. Various alternative solution approaches are compared, in terms of solution quality and execution speed, using a simplified version of the CHF scheduling problem. This investigation indicates that the Simulated Annealing (SA) metaheuristic is the most efficient solution method to provide approximate solutions. The metaheuristic solution approach allows one to model the typical sequential thoughts of a control room operator and sequential operating procedures. Thus far, these sequential rules could not be modelled in the simultaneous equation environment required for exact solution methods. An SA metaheuristic is developed to solve the practical scheduling model. A novel SA approach is applied where, instead of the actual solution being used for neighbourhood solution representation, the neighbours are indirectly represented by the rules used to generate neighbourhood solutions. It is also found that the initial temperature should not be a fixed value, but should be a multiple of the objective function value of the initial solution. An inverse arctan-based cooling schedule function outperforms traditional cooling schedules as it provides the required diversification and intensification behaviour of the SA. The scheduling model solves within 45 seconds and provides good, practically executable results. The metaheuristic approach to scheduling is therefore successful as the plant complexities and intricate operational philosophies can be accurately modelled using the sequential nature of programming languages and provides good approximate optimal solutions in a short solution time. Tests done with live CHF data indicate that the metaheuristic solution outperforms the current scheduling methodologies applied in the business. The implementation of the scheduler will lead to a more stable factory feed, which will increase production yields and therefore increase company profits. By reducing the amount of coal re-handling (in terms of throw-outs and load-backs at mine bunkers), the scheduler will reduce the coal handling facility’s annual operating cost by approximately R4.6 million (ZAR). Furthermore, the approaches discussed in this document can be applied to any continuous product scheduling environment. Additional information available on a CD stored at Level 3 of the Merensky Library. / Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2011. / Industrial and Systems Engineering / unrestricted

No description available.

Call number: LD2668 .T4 1979 N44 / Master of Science

Call number: LD2668 .T4 1984 N46 / Master of Science

The plasticity of coal during pyrolysis is of significant importance, since it affects the reactivity, porosity, particle size and the density of the char and thus also the behaviour of the char during further utilisation processes. The main focus of this study was to characterize the chemical and physical changes which the thermally treated coal undergoes, in order to better understand the pyrolysis process of caking and non-caking South African coals. The pyrolysis behaviour of three South African coals with different caking indices was investigated. The coal samples included; (1) Highveld (TWD), a medium rank C coal with a free swelling index (FSI) of 0, (2) Grootegeluk (GG), also a medium rank C coal, with a FSI of 6.5, and (3) Tshikondeni (TSH), a medium rank B coal with the highest FSI of 9. The three coal samples were classified as vitrinite-rich coals consisting of mainly aliphatic structures. Thermogravimetric experiments were used to determine the different temperatures relating to specific percentages of mass loss using set conditions. The pyrolysis process was stopped at various percentages of mass loss (thus at various stages of the reactions) to characterize the chemical structural changes that occurred at the specific mass loss percentages. The results obtained from characterization analyses indicated that the three coals differ in chemical composition and thus were expected to behave differently during pyrolysis. The coal samples consist of different amounts of macerals and minerals according to X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) analyses. The Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) results indicated that some of the functional groups within the coal samples evolved with the increase in temperature. The highly caking coal (TSH) exhibited the highest aromaticity and ring condensation. The surface areas were determined by CO2 adsorption and an increase in surface area was observed with an increase in temperature. The surface area of the GG and TSH coal-derived char samples decreased at some stage, which is an indication of thermoplastic behaviour and subsequent swelling of the coal samples. Scanning electron microscopy (SEM) images confirm the plastic stage of caking coals at specific temperatures and volatile matter release via the multiple bubble mechanism. All these results are given and discussed extensively in this dissertation. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015

The plasticity of coal during pyrolysis is of significant importance, since it affects the reactivity, porosity, particle size and the density of the char and thus also the behaviour of the char during further utilisation processes. The main focus of this study was to characterize the chemical and physical changes which the thermally treated coal undergoes, in order to better understand the pyrolysis process of caking and non-caking South African coals. The pyrolysis behaviour of three South African coals with different caking indices was investigated. The coal samples included; (1) Highveld (TWD), a medium rank C coal with a free swelling index (FSI) of 0, (2) Grootegeluk (GG), also a medium rank C coal, with a FSI of 6.5, and (3) Tshikondeni (TSH), a medium rank B coal with the highest FSI of 9. The three coal samples were classified as vitrinite-rich coals consisting of mainly aliphatic structures. Thermogravimetric experiments were used to determine the different temperatures relating to specific percentages of mass loss using set conditions. The pyrolysis process was stopped at various percentages of mass loss (thus at various stages of the reactions) to characterize the chemical structural changes that occurred at the specific mass loss percentages. The results obtained from characterization analyses indicated that the three coals differ in chemical composition and thus were expected to behave differently during pyrolysis. The coal samples consist of different amounts of macerals and minerals according to X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) analyses. The Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) results indicated that some of the functional groups within the coal samples evolved with the increase in temperature. The highly caking coal (TSH) exhibited the highest aromaticity and ring condensation. The surface areas were determined by CO2 adsorption and an increase in surface area was observed with an increase in temperature. The surface area of the GG and TSH coal-derived char samples decreased at some stage, which is an indication of thermoplastic behaviour and subsequent swelling of the coal samples. Scanning electron microscopy (SEM) images confirm the plastic stage of caking coals at specific temperatures and volatile matter release via the multiple bubble mechanism. All these results are given and discussed extensively in this dissertation. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015