4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
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Item The role of intersecting identities in career development and progression in the core disciplines of the South African mining industry(University of the Witwatersrand, Johannesburg, 2024) Mahobe, Patience Ntsoaki; Dey, SayanThe study sought to contribute to scholarship in the South African mining industry related to career development and progression in the core disciplines. Using qualitative research methods and applying intersectionality as a theoretical framework, the study examined whether, and how social identity plays a role on career development and progression in the core disciplines (mining & technical services, metallurgy, and engineering) of the South African mining industry. The study further examined whether there has been a change in the experiences of the different social identity groups related to career development and progression in the nearly thirty years since the promulgation of various pieces of legislation in South Africa in the mid- to late 1990s across industries and the mining industry in the early 2000s to transform the demographic profile across various occupational levels. The study lastly determined whether historical and current organisational, industry and societal systemic issues and dynamics impact career development and progression in these core disciplines. Thematic analysis was used to systematically identify and organise the data from the narratives of the participants provided through semi-structured interviews. This study confirms that intersectional identities have an impact on the career development and progression in core disciplines in the South African mining industry. The application of intersectionality as a theoretical framework brought to the fore different career development and progression experiences, challenges, and outcomes for the different social identity groups. Some progress in changing the demographic of the industry was noted, although progress is seen as being slow, particularly at executive level, with historical systemic issues related to entrenched ways of working and a leadership style that is not people-centric being the most difficult to change. The outcomes of the study and recommendations challenge the industry to think differently about transforming their cultures and ways of working, to create a focus on macro-level organisational systems and structures that continue to produce and reproduce unequal outcomes whilst also creating awareness and dealing with micro-level individual behaviourItem Could Not Sing in the Dead Heat: Liner Notes Under the Sun(University of the Witwatersrand, Johannesburg, 2022) Ramphalile, Molemo Karabo; Schuhmann, AntjeOn the one hand we place blackness as a historical if inconsistent category inextricable with morbidity, disfavour, depravity, mystery, wretchedness, penumbra, opacity or absence of light, and the abyssal – in both secular and religious metaphysical symbolism. On the other hand we place space as a historical and physical category denoting area, range, clearance, scope, volume, expanse, lacunae, aperture, margin, and in its instance as verb – opening, arranging, ordering, placing, separating, and locating; which in cosmography, geography and cartography finds its varied imaginative and applied interpretation. We coalesce what is in both hands in order to envisage how blackness persistently becomes and comes to be the extractable property of sub-Saharan Africans. Through various ontological-cosmographic- geographic designations such as Torrid Zone, ‘land of the blacks’ or even terra nullius, we encounter visualisations of a territory and expanse that is always either completely devoid of people or inadequately peopled, that is, the territory whence blackness as inextricably embodied (or fleshened) exists and is cultivated. Blackness: not only does it determine our modes of being, or non-being, in this world, but for us in this study, it is also an experiential, experimental and analytical lens permitting the suggestion and scribing of historical narratives and discourses that centre the inveterate decentring of blacks. In the tradition of liner notes, this study is written in a performative relation to the subject or object at hand; there under the sun, in the dead heat.Item Co-gasification of Coal and Solid Waste to Hydrogen Enriched-Syngas in a Fixed Bed Gasifier(University of the Witwatersrand, Johannesburg, 2020-10) Ozonoh, Maxwell; Daramola, Michael O.; Oboirien, Bilainu O.The economic growth of every nation around the globe is centred on energy. Energy can be harnessed from different sources using different conversion systems, but such systems should be sustainable. Liquid fuels such as petroleum and solid fuels (e.g. coal & biomass) are largely used for energy production. Energy recovery from these fuels is usually carried out using thermal chemical processes such as combustion, pyrolysis, and gasification systems. Out of the three technologies, gasification is considered the most attractive based on its efficiency and other qualities. In the gasification process, syngas is produced. It is necessary to produce syngas of high quality such as hydrogen-enriched syngas. Hydrogen-enriched syngas can be used in fuel cells, gas turbines and engines for electricity production. This type of gas burns with little gaseous emissions to the atmosphere, but its production is dependent on the type of fuel and process conditions, and energy conversion system employed. In South Africa, around 95 % of electric power production comes from coal, and the current reserve is projected to last not more than a century [8]. Secondly, the coal is fast depleting and generates a lot of gaseous emissions (e.g. CO2, NOX & SOX) that pose a huge threat to the environment. The emission of the aforementioned gases is a very serious issue in South Africa. Presently, some Carbon Capture and Storage (CCS) projects are on-going in the country, although the CCS is not the fuse of this study. The gasification of biomass waste and coal could assist in gaseous emission reduction. Similarly, large amounts of agricultural wastes (e.g. sugarcane bagasse, corn cob & pine saw dust) and other solid waste such as tyre are in abundance in SA. It is detailed in chapter 2. Majority of the wastes are disposed indiscriminately, hence resulting in environmental pollution. Importantly, the solitary gasification of biomass is very expensive considering the prices of biomass. Besides that, biomass produces large amount of tar hence, resulting in operational difficulties in the gasifier and end user facilities. In this study, co-gasification of coal and solid wastes is considered as a crucial alternative to addressing the aforementioned problems. Particularly, the feedstocks used for this study were coal, biomass (corn cob (CC), pine sawdust (PSD), sugarcane bagasse (SCB)) and waste tyre (WT) and were pre-treated by drying, milling, sieving, and torrefaction (coal was not torrefied). The fuel samples were blended with coal at different ratios as detailed in the thesis and used for the study. For the torrefaction process, the most viable torrefaction process conditions and feedstock were determined, while the torrefaction process model for the feedstocks were developed, using Response Surface Methodology (RSM) and Artificial Neural Network (ANN), respectively. The Performance efficiency of gasification systems was evaluated using experimental data obtained from a few gasifiers (e.g. entrained, fluidised, and fixed bed) operated at varied experimental conditions using blends of feedstocks (e.g. biomass, coal, waste tyre etc.). A backpropagation Levenberg Marquardt (L-M) and Bayesian Regularisation (BR) algorithms of ANN model with Multiple Input- Multiple Output (MIMO) and Multiple Input-Single Output (MISO) layer networks were considered. The results of the MIMO and MISO layer networks obtained from the L-M algorithm were better than that of BR algorithm which is in affirmation with some of the results found in the literature. For model result improvement, Input Variables Representation Technique-by-Visual Inspection Method (IVRT-VIM) and Output Variables Representation Technique-by-Visual Inspection Method (OVRT-VIM) were developed from the study. Estimation of the gaseous emissions and profits from biomass, tyre, and coal fired co-gasification CHP Plant using Artificial Neural Network (ANN) was carried out for 20-year investment period using South Africa (SA) and Nigeria as cases studies via Artificial Neural Network (ANN). Higher profits were obtained from South African feedstocks than that of Nigerian feedstocks due to cheaper price of SA coal WFO and WOFC, but the gaseous emissions (CO, NOX, & SO2) from the Nigerian fuels were lower than that of SA because of differences in compositions of the fuels. The potentials of biomass torrefaction in terms of profitability in a co-gasification CHP plant for a 20-year-investment period was carried out using blends of Coal + SCB, Coal + CC, and Coal + PSD with coal-to-biomass ratio of 50:50, 71:29, and 80:20, respectively. The two financial cases mentioned earlier were considered. Four investment terms including: (A) 1st–5th, (B) 5th– 10th, (C) 10th– 15th & (D) 15th– 20th and two operational cost models; with feedstock costing (WFC) and without feedstock costing (WOFC) were employed. An estimated profit of between USD5.9 million - USD6.5 million and USD7.8 - USD7.9 million was earned at the end of investment plan using WFC and WOFC, respectively. The Internal Rate of Return (IRR) was 5 ± 1 %/yr. and 7 ± 4 %/yr. based on South African electricity price of 0.14 $/c kWh, respectively. The parametric effect of process variables during torrefaction of coal/biomass/waste tyre blends using ANN and RSM models were studied. The variables considered were Higher Heating Value (HHV), Enhancement Factor (EF), and Sold Yield (SY). The most effective operating process conditions (in terms of blending ratio, temperature and torrefaction time: input variables) is of the order: 50:50 at 300 OC and 45 min > 50:50 at 250 OC and 30 min >50:50 at 200 OC and 45 min. Similarly, the most viable fuel follows the order of Coal + Torrefied PSD > Coal + Torrefied SCB > Coal + Torrefied CC and > Coal + Torrefied WT. Coal + Torrefied PSD has HHV of 28.27 % and an EF of 1.41. This corresponded to around 10 % increase in the HHV of the torrefied fuel when compared to the raw fuel and about 25.23% higher than the EF of Coal + Torrefied WT of 1.03. Based on the result of the EF of Coal +Torrefied waste tyre, upgrading of the fuel quality via torrefaction is not recommended. Furthermore, a comprehensive study on tar treatment techniques was carried out using tars produced from biomass and blends of biomass and coal employing biochar based and Ni-biochar based catalysts. Box Behnken Design of Experiment (DoE) method was used. A full quadratic regression model was used to develop a mathematical model for tar treatment based on the feedstocks studied. The Pine Sawdust-Biochar Catalyst (PSD-BC) and Nickel Pine Sawdust-Biochar Catalyst (Ni-PSD-BC) were the most effective in terms of tar treatment and with an average percentage amount of tar conversion of 89.76 and 96.73%, respectively. Ni-PSD-BC was more efficient for tar cracking than PSD-BC, but PSD-BC (waste base) may be more attractive if sustainability and cost effectiveness of precursors are considered. Co-gasification of coal and pine sawdust (PSD) to hydrogen enriched syngas in a fixed bed gasifier was carried out with catalyst (WCAT) at 900 OC and without catalyst (WOCAT), at 700, 800, and 900 OC, respectively. Coal-to-PSD ratio of 1:1 was used, while Nickel-pine sawdust-biochar (Ni-PSD-BC) and pine sawdust-biochar (PSD-BC) were employed as catalysts. The gases produced at 700, 800 & 900 OC using WOCAT cannot be used in fuel cells and gas turbines due to poor quality, while others produced at 900 OC WCAT, can be used in internal combustion engines and gas turbines, but unfortunately, have lower quality to be employed in fuel cells for electricity production. However, the study provides a method of beneficiation of the high ash content South African coal for energy production. The outcome of this study is also instrumental to energy security, efficiency and sustainability as well as waste management in South Africa, Nigeria and other parts of the globe. An assessment of the economic, energy and environmental viability of a 5 MW co- gasification power plant was carried out, using blends of coal and biomass, and two financial cases were considered namely: with feedstock costing (WFC) and without feedstock costing (WOFC). Feedstock profitability in the plant for energy production was evaluated. Equipment consisting was not considered. The power plant used 20,473,451.41 kg, 20,986,049.96 kg, 18,251,806.49 kg, and 15,276,277.85 kg of Coal + SCB, Coal + CC, Coal + PSD, and Coal + WT to produce the 5 MW and 5.56 MW electric and thermal power, annually. Coal + Torrefied PSD was the most profitable of the fuels studied. The use of Coal-to-PSD ratio of 4:1 for the power generation as against Coal-to-PSD blend ratio of 1:1 resulted to an annual loss of about ZAR6, 461,301.77 ($90,458,224.70) and ZAR123,782.47 ($1,732954.58) WFC and WOFC, respectively.Item Energy storage properties of carbon onion-carbon nanofibre composites containing transition metal compounds(University of the Witwatersrand, Johannesburg, 2022) Khawula, Tobile Nokuphiwa Yollanda; Ozoemena, K. I.The quest for electrical energy storage has been a key driver for researchers to come up with more effective means of storing this form of energy due to the intermittent nature of renewable energy sources. Several countries have swiftly adopted the transformative potential of renewables, in particular solar energy, while others have delayed the implementation due to complex policies surrounding renewable energy projects. A way forward would be innovative regulatory approaches that encourage the pairing of solar systems with other generation technologies, and with storage, to offer a “round the clock” supply. Rechargeable batteries and supercapacitors are widely employed energy storage systems. A rechargeable battery system offers high energy density, with lithium-ion batteries (LIBs) being the most widely used. For some applications, it is imperative that energy is delivered at a much faster rate. This characteristic feature is known as power density, and supercapacitors have proven to be much better than batteries in this case. The large-scale commercialization and adoption of a supercapacitor are hindered by its low energy density. The electrode material is a major determinant of the success of supercapacitors. Generally, these are supported on high surface area carbon materials. This study focused on the development of electrospun polyacrylonitrile (PAN) fibres embedded with onion- like carbon (OLC) and iron (II) phthalocyanine (FePc) particles, and encapsulation of the fibres with Molybdenum disulphide (MoS2). Furthermore, composite fibres were either integrated with manganese (III) oxide (Mn2O3) or engineered with defects for enhanced performance in symmetric supercapacitors. The synthesis of electrode materials was divided into four phases; In the first phase (1), OLC nanoparticles were embedded in electrospun PAN fibres and decorated with the Mn2O3 and evaluated as supercapacitor electrode materials. For enhanced interfacial electrochemistry and overall capacitance, the electrode material in (1) was encapsulated with MoS2 in phase (2). In phase (3) FePc embedded in the PAN electrospun fibres were evaluated for supercapacitor applications. Limited specific capacitance and poor cycling stability were observed, thus suggesting integrating OLC and further encapsulation with MoS2, in phase (4). The morphology of the fibres was vii engineered with defects in the form of Fe2+ vacancies to maximize the electrochemical reactions of the OLC/MoS2 fibre composite. The electrochemical properties of the fibre composite materials were investigated and OLC/Mn2O3-CNF exhibited a specific capacitance, energy and power density of electrodes were 200 F g-1, 44.63 Wh kg-1 and 3 235 W kg-1, respectively with excellent capacitance retention. While the MoS2 encapsulated and Mn2O3 decorated fibre composite, OLC/MoS2@Mn2O3 displayed a specific capacitance, energy and power density of 348 Fg-1 18.42 Wh kg-1 and 5 095 W kg-1, respectively. It is pertinent to note that the capacitance of the electrodes was retained throughout the 5 000 cycles of the charge-discharge test. Upon thermal treatment at 600 °C, FePc-PAN transformed into FeN4-CMF and exhibited a specific capacitance, energy and power density of 147 F g-1, 12.48 Wh kg-1 and 4 320 W kg-1, respectively. The vacancy-rich (FeN4)d-OLC- CNF@MoS2 composite obtained by the removal of Fe2+ atoms, showed a specific capacitance, energy density and power density of 481 F g-1, 76 Wh kg-1 5833 W kg-1, respectively. This study underscores strategic processes that can be adapted in the design, synthesis and optimization of supercapacitors-based electrodes for enhanced performance.Item The Political Economy of Energy Regulation in the Coal Mining Industry of Emalahleni(University of the Witwatersrand, Johannesburg, 2023-06) Selebi, Elton Jimmy; Matshabaphala, ManamelaThis study explores the perspectives on the political economy of energy regulation in the coal mining industry of Emalahleni. It seeks to discuss whether there are adequate steps within the political and economic sphere that regulates the efficient supply of electricity. The goals of this study are to ascertain the extent of regulation and policy formulation in the coal mining business in Emalahleni, South Africa; examine the reasons for decision-makers’ inaction in promoting a sustainable energy transition in Emalahleni, South Africa, and to identify political channels and platforms that can garner public and/or political support to speed the region's transition to sustainable energy. This research draws upon theoretical discussions centred on the following: The Agency Theory, Classical Political Economy, Keynesian Economics, and the Political Theory of Governance. Informed by an interpretivist paradigm, the qualitative research approach will be employed to explore the political economy of energy regulation within the study area. A non-probability sampling approach through the use of judgemental sampling was used to select the research participants, and the research method utilised interviews through the distribution of a questionnaire. A sample size of 20 comprised individuals from mining organisations in Emalahleni, Department of Mineral Resources and Energy Officials, CGS, Petroleum Agency SA, COSATU, and the Department of Trade Industry and Competition. The study noted that the political system has an impact on the energy and coal regulation markets at Emalahleni. It is recommended that an efficient energy resource policy and local governance are required to address the challenges of increased energy demand and pollution in South Africa.Item Utilisation of liquefied natural gas as energy by heavy-duty vehicles in South Africa(University of the Witwatersrand, Johannesburg, 2024) Tlalang, KgosietsileThe transport sector in South Africa significantly contributes to greenhouse gas emissions, with over fourteen percent of the total emissions attributed to it. The reliance on fossil fuels, particularly diesel, for vehicular road transportation exacerbates this issue. High operating costs per kilometre of diesel negatively affect the sustainability of heavy-duty vehicle operations. To address these challenges, a conceptual framework was employed to investigate various factors influencing the decision-making process to adopt LNG as an alternative fuel. Qualitative research methods were utilised to gain insights into the owners’ environmental awareness, economic considerations, and long-term sustainability goals regarding LNG adoption. The findings reveal a growing interest among heavy-duty vehicle operators in transitioning to LNG because of its environmental benefits, cost efficiency, and long-term sustainability prospects. Key stakeholders such as vehicle manufacturers, fuel providers, and logistics services are actively exploring LNG solutions to enhance fuel diversity, reduce emissions, and achieve cost efficiencies. Volvo Southern Africa, a major heavy-duty vehicle manufacturer, is leading efforts to provide environmentally friendly solutions to the industry. Similarly, some logistics services providers are undertaking pilot programmes to explore alternative energy technologies as part of their commitment to environmental sustainability. The research underscores the potential of LNG to transform the heavy-duty vehicle sector by offering a cleaner, more sustainable fuel alternative. Analysis of the estimated payback period and net present value demonstrates the economic viability of LNG heavy-duty vehicles compared to diesel counterparts. However, to realise the full potential of LNG adoption in South Africa, investment in infrastructure for importation and distribution is crucial. Additionally, concerns about potential government levies and taxes on LNG need to be addressed to encourage its utilisationItem Organisational Development Strategies to Mitigate Strike Action in Mining Companies in South Africa(University of the Witwatersrand, Johannesburg, 2024) Tanyanyiwa, Olivia Tashinga; Matshabaphala, Manamela; Nixon, OcharaThis study delves into the challenges faced by the mining sector in South Africa due to frequent strike actions and explores various organizational development strategies that can be implemented to mitigate these occurrences. The research highlights the significance of effective communication, employee engagement, conflict resolution mechanisms, and leadership development in fostering a positive work environment and reducing the likelihood of strikes. By drawing on relevant literature, case studies, and expert opinions, the study aims to provide valuable insights for mining companies operating in South Africa to proactively address labor disputes and promote sustainable industrial relations. Through the implementation of strategic organizational development initiatives, mining companies can create a culture of trust, collaboration, and mutual respect among employees and management, ultimately leading to improved productivity and stability within the sector.Item Exploring an optimal franchise agreement model for the fuel retail industry in South Africa(University of the Witwatersrand, Johannesburg, 2024) Sakoane, Motshidisi Mary-AnneThis study explores the complex landscape of fuel retail franchise agreements in South Africa, highlighting the multifaceted challenges and strategic imperatives facing both franchisors and franchisees. The research underscores the importance of sustainable partnership models and adaptive business practices amidst a dynamic market environment. Key findings reveal a complex interplay of regulatory frameworks, market dynamics, and consumer trends, which significantly influence fuel retail franchise agreements. The study emphasises the need for franchise agreements that prioritise flexibility, clarity, and adaptability to ensure mutual benefit and long-term viability. The research contributes to understanding the complexities and challenges within the fuel retail industry, providing valuable guidance for stakeholders. It informs strategic decision-making and offers recommendations for improving franchise agreements, ensuring they meet the evolving needs of the market. The study also highlights limitations, including the specificity of the South African context and the dynamic nature of the industry, and suggests areas for future research, such as the impact of emerging technologies and consumer preferences on franchise operations.Item Assessing the Contribution of Mining Companies to the Development of Entrepreneurs(University of the Witwatersrand, Johannesburg, 2023) Mathoma, Khuthalani CurtisThis MBA thesis entitled “Assessing the Contribution of Mining Companies to the Development of Entrepreneurs” investigates the current state of entrepreneurship in South Africa, concentrating on the mining sector. The study analysed the extent to which mining companies have invested in entrepreneurship development in the areas where they operate, and the challenges that they face in promoting entrepreneurship in South Africa. A qualitative research approach and a case study design were employed, with data collected through face-to-face interviews with CSR and Enterprise and Supply Development representatives from gold and coal mining companies in Gauteng and Mpumalanga provinces, as well as beneficiaries and participants of the mining companies' CSR and Enterprise and Supplier Development programs. Thematic analysis was used to analyse the data. The study found that entrepreneurship in South Africa faces numerous challenges, including lack of access to finance, inadequate business skills, limited market opportunities, and regulatory challenges. However, mining companies have made significant investments in entrepreneurship development in the areas where they operate through corporate social responsibility initiatives and enterprise and supplier development programs. Mining companies provide financial and non-financial support for entrepreneurship development, including funding programs, loans, mentorship, and training programs. The study also found that mining companies face several challenges in promoting entrepreneurship in South Africa, among them is the absence of a culture of entrepreneurship in mining communities, limited access to finance and resources, and regulatory challenges. Despite these challenges, iv beneficiaries, and participants of mining companies' CSR and ESD initiatives generally perceived the programs as supportive of the development of their entrepreneurial ventures. Finally, the study recommended strategies that mining companies can adopt to enhance their contribution to the development of entrepreneurship in the country. Overall, this study offers insightful information about the function of mining companies in promoting entrepreneurship and highlights the importance of their continued investment in entrepreneurship development in South Africa.Item Evaluating continuous improvement models to enhance organisational productivity in a diamond mining operation(University of the Witwatersrand, Johannesburg, 2024) Chele, Motsi; Venter, RobertsEvaluating continuous improvement models to enhance organisational productivity in a diamond mining operation. The study used qualitative methods to establish an appropriate continuous improvement methodology that will assist to enhance organisational productivity. The application of continuous improvement technique to help the organisation bridge observed non-productivity was the research gap being addressed. The study identified factors that are important for organisational productivity. The study went in details to unpack organisational productivity, internal business processes and continuous improvement methodologies. This research established the model to support the business practice. The challenges observed during the research study required a systemic approach, strong leadership support, effective communication and a commitment to building a culture of continuous improvement within the organisation to deal with them and easy the workflow. The research study concluded that Theory of constraints was the relevant methodology to be adopted by the organisation to deal with lack of productivity which is currently the major challenge. It is envisaged that the nominated continuous improvement methodology would be implemented and tested to validate its capabilities to drive the organisation to an acceptable productivity level.