Thesis is submitted in partial fulfilment for the degree of Master of Science in Metallurgical Engineering to the Faculty of Engineering and the Built Environment, at the University of the Witwatersrand, Johannesburg, 2017 / Abandoned mines in South Africa have created a series of environmental legacies around the mining community in the form of health hazard (air pollution), land degradation and illegal mining activities. The biggest mine environmental legacy that is being addressed today in South Africa is that of abandoned mines, particularly asbestos and the process of cleaning up asbestos mining dumps in South Africa as implemented by Mintek (state owned mineral processing and metallaurgical research instistute)on behalf of Department of Mineral Resources (DMR) and this form the main basis of this research study. The history of abandoned mines, particularly asbestos mining, is that the mining peaked and took place during the time when there were no environmental regulations forcing mining companies to take control of their waste. The only legislation was the Atmospheric Pollution Prevention Act (Act No.45 of 1965). The Mineral Act, which regulated most of the mining activity in South Africa was promulgated in 1991 and was enacted as Act No.50 in 1991. Apart from the environmental challenges, these mines are located in rural areas with high unemployment levels and poor infrastructure, and therefore all solutions would require these matter to be addressed as well. This study was based on a literature review involving bamboo as a potential vegetation cover to be grown on abandoned mineland both for rehabilitation and with intention to harvest it for energy use. This would hope to address some of the socioeconomic issues within the communities surrounding such abandoned asbestos mines. Penge area in the Limpopo Province is proposed as the site for a pilot study for such bamboo cultivation. Bamboos are a large group of rapidly growing woody grasses, mainly found in the IndoChina regions of the world that can be sustainably managed in short-cycle harvesting schemes. They offer many benefits like erosion control, architectural properties for rural construction activities and can be used as biomass feedstock for the bioenergy economy. The results of this study indicate that it is possible to grow bamboo in the Penge based on its physio-climatic conditions. The literature review proposes , Bambusa balcooa, Dendrocalamus asper, Dendrocalamus strictus and Phyllostachys edulis as suitable bamboo species for the region. Based on rudimetary simple evaluation model the area will produce 14 tonnes/ha/year of biomass in the 5th year of harvesting, increasing to and stabilizing to 47 tonnes /ha/year in the 7th year and it has proven economically feasible to proudce energy from the amount of feedstock generated. / XL2018

[Truncated abstract] Acidic mine lakes are formed as a result of the oxidation and dissolution of metal sulfide minerals and are primarily characterized by low pH values of 2 – 4. Many strategies for the bioremediation of acidic mine lakes depend on the alkalinity generation capabilities of microbial ferric and/or sulfate reducing bacteria. However nearly all mine lakes are oligotrophic, with very low concentrations of available organic carbon and nutrients; all required for healthy microbial growth. There is also an unusual class of mine lakes characterized by low concentrations of organic carbon and also very low concentrations of dissolved iron and sulfate. Our ability to promote microbial activity in these systems is especially challenging. This study focuses on one of these systems, Lake Kepwari, a coal mine lake in Western Australia. Numerical modeling of remediation strategies is an efficient way of testing scenarios prior to expensive in-field trials. However such modeling relies on good descriptions of microbial processes, including kinetic parameterizations of ferric and sulfate reduction. There has been little research to date on the study of kinetic parameterizations of the chemical and biological alkalinity generation in acidic mine lakes. The objectives of this thesis were to investigate the viability of microbial ferric and sulfate reduction in an ultraoligotrophic, acidic mine lake, to assess the impact of these microbial processes on water quality and to parameterize the Dual Monod kinetics of neutralization under dual limitation conditions. Molecular analyses including most probable number, DNA extraction, polymerase chain reaction, polymerase chain reaction – denaturing gradient gel electrophoresis were used to examine the microbial communities in the lake sediments. ... The Monod maximum specific microbial growth rates with respect to dissolved organic carbon and ferric, and as determined in batch experiments, were 0.07 ± 0.01 and 0.048 ± 0.02 day-1, respectively, and their corresponding Monod half saturation constants and were 14.37 and 5.6 mmol L-1. The Monod maximum consumption rates under ferric and OC limitation were also estimated. The Monod maximum specific microbial growth rates with respect to dissolved organic carbon and sulfate, , and were 0.05 ± 0.01, 0.08 ± 0.01 and 0.07 ± 0.02 day-1, respectively, and their corresponding Monod half saturation constants, and were 75.5, 131.8 and 10.2 mmol L-1. The Monod maximum consumption rates under sulfate and OC limitation were also estimated. The results of this study suggest that strategies for the remediation of ultraoligotrophic, acidic mine lakes may rely on microbial ferric and sulfate reduction, however additions of both organic carbon and sulfate/ferric are essential. These results can be immediately applied to mesocosm studies in outdoor enclosures and to the management of acidic mine lakes. Furthermore, this thesis has provided a new, valuable understanding on the Dual Monod kinetic parameterizations of neutralization for an ultraoligotrophic, acidic mine lake environment. These parameterizations are essential for the lake ecological models that will be used to investigate remediation scenarios for acidic mine lakes.