Browsing by Author "Manjengwa, Evelyn Ruvimbo"

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    Evaluating the economics of and business models for metal recycling from waste printed circuit boards in a South African context
    (Stellenbosch : Stellenbosch University, 2019-04) Manjengwa, Evelyn Ruvimbo; Dorfling, C.; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Process Engineering.
    ENGLISH ABSTRACT: Electronic waste is the fastest growing component of solid municipal waste in South Africa however limited processing capacity exists in the country to economically recover metals from printed circuit board (PCB) waste. Presently the majority of recycled e-waste is exported instead of adding value to the processed material. A hydrometallurgical process entailing the selective leaching of gold and copper from waste printed circuit boards was developed by the research group (Rossouw, 2015; de Waal, 2018). This study sought to evaluate the economic and business viability of the proposed hydrometallurgical process within the South African context. A PESTEL approach was used to evaluate the South African recycling landscape. In this approach the status of the political, economic, environmental, legal, social and technological aspects characterising e-waste recycling and management was undertaken. Different business models were developed around the main activities of the associated operations of the proposed process. Screening and selection was done on two levels. An assessment of the collection and dismantling of e-waste was done and used as the first basis for screening the business models. It was established that the reverse logistics and associated manpower requirements and efficiencies associated with this operation were economically and operationally restrictive. Detailed costing and profitability studies were done on the last eight business models. The recovery of copper and gold in the metallic state was found to be associated with the highest capital and annual operating expenditures. Profitability studies were conducted on two levels. Performance analysis over the life of the project was done on the basis of discounted cash flows, time, cash and interest. The profitability ratios that included return on investment (ROI), capital ratio (CR), terminal capital rate of return ratio (CRRterm), present value ratio (PVR), net profit margin (NPM) and the (fixed asset turnover ratio) FATR were used to assess the annual performance of each business model. Both assessments revealed that all the business models under the specified process conditions, were unviable and incapable of both capital and interest repayment. Detailed sensitivity studies of the group 4 business was done. The risk of failure within five years was certain as evidenced by the perpetually decaying plots of the recapitalization risk curves. Four additional significant areas of risk were identified and evaluated that had an impact on the performance of the business models. These included supply and demand constraints, key raw material, technological and market related risks. A consideration of alternative revenue streams from palladium, silver and tin recovery, did not improve the performance of the business models. Decreasing both the capital costs and operating costs by margins ranging between 48% and 65% shifted the performance of the business models. The success of this project was driven strongly by the gold business, evidenced by improved performance at elevated minimum gold concentrations ranging between 563ppm and 925ppm. These concentrations implied that a consistent supply of high grade WPCBs would have to be furnished to ensure project viability. It is necessary to consider alternative processing routes when using medium grade WPCBs.
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    Incorporating sustainable practise principles into development of solutions for mitigation of mine waste
    (Stellenbosch : Stellenbosch University, 2024-03) Manjengwa, Evelyn Ruvimbo; Tadie, Margreth; Dorfling, Christie
    ENGLISH ABSTRACT: Mining in its nature is a capital intensive, spatially invasive global undertaking characterised by negative environmental, political and socio-economic legacies. Increased regulatory compliance, institutional pressures and access to information has necessitated a proactive and holistic shift in business practices and, governance of the mining industry. Therefore, there is an increased urgency for more holistic frameworks contributing to consistency in measurement and monitoring of environmental, social & governance (ESG) performance in mining related projects. To this end, different researchers have endeavoured to develop such frameworks combining two or more sustainability pillars. In response to the existing pressures, threatening the viability and legitimacy of the industry in general, the goal of the PhD study sought to develop a holistic decision-making framework embodying sustainable practice principles useful for informing mining projects. In this regard the use of sustainable practice principles refers to the intentional engagement of economic, social and environmental sustainability metrics in the development of the decision-making framework. Such projects include for example, mine waste management, effluent reuse and mine waste valorization etc. Therefore, the framework development was contingent on the existence of demonstrated and sustained pressures located in the business ecosystem and broader macroeconomic environment. Secondly, the framework development was also contingent on the existent scope to improve the approach to decision making frameworks. As a result, the pillars supporting the framework’s development were based on a developed understanding of different stakeholder priorities. The stakeholder priorities were identified using two perspectives, chiefly the multi-stakeholder and company-based perspectives. Underpinning management theories and schools of thought that informed the framework’s development included, the stakeholder, shareholder, agency and institutional theories. At the same time, schools of thought, such as principle-principle conflicts, legitimacy and clientalism were also used to support the framework’s development. The management theories and schools of thought were useful in developing a frame of reference that enabled a connection between the observations made in literature and the attitudes and reactions observed across different stakeholder groups, to mining related projects. To understand the stakeholder priorities from a multi-stakeholder perspective, a detailed examination of literature on varied discourses associated with extractive industries and society was undertaken. The exploratory study ultimately led to the development of a quantitative method (Value Analysis Tree (VAT) framework) to assess stakeholder perceptions’ of the value of mining projects. To understand stakeholder priorities from a company perspective, a sustainability performance assessment was undertaken for a selected gold miner, Company X. Life cycle-based approaches Environmental Life Cycle Assessment, dynamic Societal Life Cycle Assessment and Social Organisational Life Cycle assessment (ELCA, dSLCC and SO-LCA) were used to examine the relevance of mine tailings reprocessing to the business. An interrogation of the mining company’s organic growth strategy supported by mine waste valorization, specifically tailings reprocessing, was undertaken. The sustainability performance was gauged against established industrial and normative metrics, the company's strategic objectives captured by its key performance indicators, contextual regulations and policies and, finally against the level of attainment of the sustainable development goals (SDGs). As a result, the implications on the company and its stakeholders, following the inclusion of mine waste valorization were documented. The output of the life cycle studies confirmed that motivators shaping decision making priorities across different stakeholder categories, are tied to the known and perceived costs, risks and benefits associated with a mining project. Using this understanding of stakeholder priorities from a multi-stakeholder (applying the VAT framework) and a company perspective, a Multicriteria-Multistakeholder Decision Making (MMD) framework capturing the sustainability and business metrics, was then developed and tested successfully in Microsoft excel. Different decision and management-based theories underpin the framework’s development. The MMD framework was developed considering normative, rationalist and intuitive approaches. Research novelties: Mining company growth strategy was interrogated using Life Cycle thinking. No literature documents the explicit use of dSLCC, ELCA and SO-LCA to interrogate organisational growth strategy supported by production operations in mining. Additionally, a holistic approach (MMD framework) was developed that consolidates the sustainability and business-based perspectives to support decision making associated with mine waste management projects. The MMD framework will need to be tested further using other case studies to validate its applicability.