Electronic Theses and Dissertations (Masters)
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Item A holistic approach to the design of two tonnes temporary support systems (nets, mechanical props, hooks and roof bolt face plates)(University of the Witwatersrand, Johannesburg, 2024) Modika, MosesIn 2019, Thembelani Mine experienced a high number of injuries caused by Falls of Ground (FOGs) in the face area. To address this issue, safety nets with a capacity of two tonnes were urgently introduced. The two tonnes safety nets were intended to hold FOGs with a maximum mass of 1.78 tonnes, thereby providing a factor of safety of 1.1. However, in 2020 a FOG accident occurred during a drilling shift when a rock with a mass of 1.65 tonnes fell, leading to the death of an employee. The square headboard mechanical props with headboard dimensions of 130 mm x 130 mm, which were supposed to hold the safety net, were pulled out by the FOG, thereby allowing the safety net to collapse with the FOG. The slipping out of the square headboard mechanical props was due to a smaller headboard surface area of 130 mm x 130 mm in contact with hangingwall and a pretensioned load of 0.86 tonnes to 1.43 tonnes which could not sustain a falling rock with a mass of 1.65 tonnes. As a result, the square headboard props were immediately replaced with T-shaped Grease box mechanical props with average pretension load of 2.23 tonnes, larger and longer headboards of 370 mm x 100 mm to increase resistance to slipping out. The T-shaped Grease box mechanical props come with 16 mm flexible G-hooks attached to the headboards. The T-shaped Grease box mechanical props were tested at a drop test facility together with two tonnes Rock- stop safety nets and found to be able to hold two tonnes mass when installed at a standard spacing of 1.5 m x 1.5 m. This indicated that components of the temporary support systems other than the two tonnes Rock-stop safety net were not considered during the roll out. These components include 12 mm diameter flexible G-hooks, roof bolt face plates with a thickness of 4.5 mm, and square headboard mechanical props with welded 12 mm U-hooks and headboard dimensions of 130 mm x 130 mm. Therefore, it was decided to conduct a study to test the temporary support systems holistically using installation scenarios as practiced at Thembelani Mine as opposed to testing each of the constituents of the systems individually. The aim of the tests was to assess if all components fulfil the requirements of the two tonnes temporary support systems from system test point of view. iv While conducting the study, it was found that the safety nets were introduced without considering all aspects of the temporary support systems, such as safety net deflection parameters, hooks, mechanical props, and roof bolt face plates. Moreover, it is necessary to maintain a safe working height within a specific stoping width, which is the vertical distance between the footwall and the safety net in the hangingwall after holding a falling rock. This is to ensure that the employee underneath the net does not get struck by the FOG which deflected with the safety net. The study aimed to identify the items that did not meet the two tonnes systems' requirements and recommend improvements to ensure they function as expected. The study was conducted at available drop test facilities such as NCM and Videx, simulating the installation scenarios as practiced at Thembelani Mine. The study revealed that the two tonnes Rock-stop safety nets, along with 6 mm face plates, 14 mm Carbon steel S-hooks, or 14.5 mm Spring steel G-hooks, fulfilled the requirements for the two tonnes systems. The two tonnes Rock-stop safety nets and T-shaped Grease box mechanical props with flexible 16 mm G- hooks also fulfilled the two tonnes’ requirements. The study determined that the systems that fulfilled the two tonnes’ requirements were effective for all stopes at Thembelani Mine with heights of 1.2 m and 1.4 m and flat excavation ends with a height of 3.2 m, with deflection limits of 0.35 m, 0.55 m and 1.3 m respectively. In 2022, an alternative to the safety nets, the MINAX 80/3 Blast-on Mesh (BOM) with 8 mm blast-on cable, was introduced. The BOM underwent a similar study to the Rock-stop safety net, and the drop tests showed that the deflections obtained with the BOM in various scenarios as installed at Thembelani Mine were all above 0.35 m but less than 0.55 m. Hence, BOM can be used in stopes and flat excavations with heights of 1.4 m and 3.2 m, respectively.Item An assessment of the Angolan mineral taxation regime: considerations for possible improvements on government´s revenue(University of the Witwatersrand, Johannesburg, 2024) Africano, N´djamila Hilifavale Borges; Mtegha, HudsonAngola is host to 36 of the 51 critical minerals in the world and ranks third in mineral exports, totalling over USD 1 billion in 2020, and third in diamond production; Botswana and South Africa hold the top two slots, respectively. These untapped opportunities make the Angolan mining industry an excellent place to invest despite the mining industry contributing less than 1% to GDP and has yet to become a driver of economic diversification. In June 2022, Angola joined the EITI, bringing a welcome improvement in the transparency of the sector´s governance and reform, intended to attract new investors. The study evaluates the effectiveness of the Angolan mineral fiscal system as a tool for maximising revenue for the benefit of its citizens and securing investment (local and foreign) to promote linkages and broad-based national growth and development. Four objectives were examined in this study: (i) Conduct a situational analysis of the current fiscal regime through a comparative analysis of headline rates in regional and international countries; (ii) Qualitative evaluation of the effectiveness and efficiency of the mineral fiscal regime; (iii) Analyse the tax revenues raised by the mining industry between 2011-2021; (iv) Make possible recommendations to improve the current mining tax regime. The study employed a descriptive survey design with a qualitative and quantitative approach for data collection and analysis. The main findings include: (i); Angola's political economy setting resembles that of a hegemonic government characterised by an institutionalised one-party regime whereby the implications on the mineral fiscal regime are multifaceted, affecting investment, regulation, revenue sharing, and sustainability; (ii) Both mineral royalty and corporate income tax rates, are within regional and international norms and have consistently contributed a significant share of the government's direct tax revenues over the last eleven years; (iii) Prevailing fiscal regime can be improved through a combination of tax instruments such as resource rent-tax or profit-based royalty with a basic ad valorem tax system; (iv) However, Angola’s primary challenges point to a possible absence of enforcement and compliance mechanisms for both the mining code iii and the sector fiscal framework, as well as the need to strengthen government agency capacity to oversee and gather fiscal contributions from the sector. In light of these findings, it is recommended to (i) Improve the sector's mining code and fiscal legislative framework and enforce it; (ii) Conduct a study to analyse the effects of all government taxes (direct tax, indirect tax and non-tax instruments and tax incentives) on both the industry and the government´s treasury; and (iii) Conduct further studies on the proposed optimal mineral fiscal regime. Finally, an effective, efficient, and transparent mineral fiscal system can only exist first and foremost through intentional collaboration and alignment of objectives among the sector’s stakeholders.Item An investigation into equity market timing practices by South African mining companies(University of the Witwatersrand, Johannesburg, 2024) Matumba, LindelaniThis research examines the practice of equity market timing among 30 Johannesburg Stock Exchange (JSE)-listed mining companies from 2006 to 2022. Mining companies, characterised by their capital-intensive nature, rely on management for optimal capital management, which includes both the acquisition of capital through debt or equity and its optimal allocation. The concept of equity market timing, introduced by Wurgler and Baker in the 1990s, suggests that company management may engage in timing the equity market when they perceive their stock to be mispriced. This study incorporated control variables such as market-to-book value (a relative valuation metric that investors use to assess a company's market value in relation to its book value), asset tangibility, degree of leverage, and profitability. Panel regression analysis, utilising both fixed effects and random effects, revealed that market-to-book value was not statistically significant at the 5% level. The overall R-squared value was 58.8%. Given the lack of significance for market-to- book value and asset tangibility, it is recommended to consider other capital structure theories, such as the pecking order or trade-off theory. Additionally, incorporating variables like interest rates and other macroeconomic factors could help address the potential for omitted variable bias.Item Analysis of factors affecting rehabilitation of abandoned mines in South Africa: cases on asbestos projects(University of the Witwatersrand, Johannesburg, 2024) Meyerowitz, Reuben BenjaminAsbestos was once mined in South Africa using traditional methods. Unfortunately, the exploitation of asbestos severely impacted both workers and the surrounding communities. In 2008, the government stopped asbestos mining and designated the abandoned mines as Derelict and Ownerless (D&O) Mines. This was done to mitigate the serious health and safety risks associated with asbestos mining. The aim of the programme was also to address the negative environmental impacts caused by abandoned mines on local areas and social environments. Since 2009, the MINTEK’s D&O programme has rehabilitated 38 mines. However, the rehabilitation of these mines has been affected by various factors that have impacted the Derelict and Ownerless mining projects. This study aims to identify and understand the factors that affect abandoned mine projects in South Africa. The study also aims to provide a comprehensive analysis of the identified impacts and provide recommendations to ensure the successful implementation of the D&O projects. The study used a mixed-method approach to collect both quantitative and qualitative data. The methodology involved data collection from various sources such as recorded reports, financial statements, spreadsheets, engineer reports, project progress reports, construction programs, and document analysis. The study focused on 32 asbestos mining projects in four provinces, namely Northern Cape, Limpopo, KwaZulu Natal, and Mpumalanga, which were used as case studies. The rehabilitation of abandoned asbestos mines is a challenging task that requires collaboration, innovation, and concerted efforts. The factors affecting the implementation of the rehabilitation projects include slow decision-making by the contractors before and during construction, internal challenges faced by the contractors, time delays in material and stock deliveries, community resistance, specific project team experience, influence of external stakeholders and others. These can be categorized into six areas, namely, technical, economic, management, psychological, political and legislative. The study has revealed that all factors identified in the research have a direct impact on rehabilitation projects and contribute to failures in meeting targets in terms of costs and time. In conclusion, the analysis of technical, economic, psychological, and political factors in the rehabilitation of abandoned mines iv in South Africa also highlighted the interconnected nature of these considerations. As such, resolving these factors collectively will enhance the success and sustainability of mine rehabilitation projects. The recommendations from the study include improvements in contract management, ensuring project monitoring and evaluation that encompasses progress monitoring, data management and reporting, and the establishment of performance matrices. The other areas of intervention include policy and legal reforms to define the requirements and objectives of rehabilitation projects. Stakeholder engagement and capacity building are also key elements that have a major influence on the successful implementation of rehabilitation projects. By prioritizing factors and addressing these bottlenecks, the risks associated with asbestos rehabilitation can be mitigated to foster resilient and empowered communities that actively participate and benefit from the restoration processes.Item Application of Data Analysis and Machine Learning to Develop a Maintenance Strategy for Load-Haul-Dump (LHD) Machines at Booysendal Mine(University of the Witwatersrand, Johannesburg, 2024) Malambule, Thulani Mduduzi; Mabala, Mahlomola Isaac; Nwaila, GlenThis report focuses on applying data analysis and machine learning to develop a maintenance strategy for load-haul-dump (LHD) equipment at Northam Platinum’s Booysendal underground mine. This operation predominantly relies on trackless mobile machinery, with a significant emphasis on LHD machines. The mine maintains daily records of mechanical equipment breakdowns. However, Booysendal's reliance on a reactive “run-to-failure” maintenance system has led to operations outside a predefined maintenance plan. The objective of this research was to apply data analytics to understand trends in the dataset and extract meaningful insights regarding LHD breakdowns. It aimed to develop a predictive maintenance model for LHD machines using appropriate machine learning models. Lastly, to design a data-driven maintenance strategy based on insights from data analysis and machine learning (ML). The hydraulic system and transmission components were found to contribute 80% towards downtime. The K-Nearest Neighbours (KNN) regressor was chosen as the best regression model, achieving the lowest Root Mean Square Error (RMSE) of 2.02, while the Support Vector Machines (SVM) classifier was selected as the best classification model with the highest accuracy of 60%. Recommendations on how the predictive models could be improved were highlighted. Finally, a hybrid maintenance strategy is proposed for proactive optimisation. The strategy entails integrating predictive analytics, real time condition monitoring and threshold-based alerts to enable proactive maintenance actions. The proactive actions include ensuring availability of critical spares and conscientizing LHD operators on failures related to bad operating practises.Item Assessing the Challlenges in the Valuation of Early-Stage Secondary Diamond Deposits(University of the Witwatersrand, Johannesburg, 2024) Ganda, Nair da Conceição de Oliveira Gavião; Marshall, Tania R.Diamond mining is a fundamentally important part of the economy in many countries. Globally, some of these countries are home to early-stage alluvial diamond projects that attract significant interest from investors. Often, these investors need to understand the project’s value to make informed decisions. However, valuing early-stage alluvial projects is a complex and challenging process. This research report identifies and assesses the challenges associated with the valuation of early-stage alluvial projects through a case study of a project in Angola. For the case study, a valuation exercise was conducted using both the Cost Approach and the Market Approach. The research identified challenges specific to the Cost Approach, such as data availability and compliance with internationally recognised Resources and Reserves reporting codes. Likewise, challenges specific to the Market Approach included estimating current commodity prices and checking the performance of alluvial diamond properties on an applicable stock exchange. Additionally, it became clear that complications related to both approaches, such as experience and resource estimation methodologies, need to be addressed before a final valuation range can be determined. Although there are several difficulties, the valuation of early-stage alluvial projects is still possible. Nonetheless, these challenges impact the accuracy, consistency, and interpretation of the valuation results. Therefore, becoming familiar with these challenges and the recommendations made in the report will help valuators avoid potential pitfalls and contribute significantly to the field by guiding more informed decision-making in the valuation of early-stage alluvial diamond projects.Item Assessing the policies for legalising artisanal and small-scale mining in south africa(University of the Witwatersrand, Johannesburg, 2024) Komape, Ledile Jane; Marshall, T. R.This research examines the regulatory framework of artisanal and small-scale mining in South Africa, discussing issues around whether the current policies are up to the challenge of managing the realities and expectations of artisanal and small-scale miners. The research was conducted through a survey of three focus groups across four areas in South Africa using structured questionnaires and interviews. Data collection involved contacting individuals at the Department of Mineral Resources and Energy, Mine Health and Safety Council, and Mining Qualifications Authority, as well as Artisanal and Small-Scale Miners and mine representatives, and conducting interviews at their offices, homes, or workplaces based on their preferences. Data collected from the three focus groups reveal a disconnect between the goals of the policies and how the artisanal and small miners’ communities experience them, emphasising the need for effective policy implementation, comprehensive education initiatives, and avoidance of unrealistic expectations. Key recommendations of the research include the adoption of digital technologies for monitoring, fostering cooperative models, and encouraging international collaboration between local and foreign operators. It underscores the importance of creating and applying inclusive, equitable and sustainable policies to improve the socio-economic and environmental conditions of artisanal and small-scale miners in South Africa.Item Back analysis of previously stooped Panels to improve the safety and productivity of future stooping operations at new Denmark colliery(University of the Witwatersrand, Johannesburg, 2024) Gonsalves, RicardoNew Denmark Colliery (NDC) is a Seriti-owned underground coal mine in the Mpumalanga Province. It started stooping operations towards the end of 2018 and has since stooped 50 panels safely across all three of its shafts. NDC selected the NEVID method, which is known for its safety and success in neighbouring mines. Initially stooping panels in the 1100 block, NDC encountered challenges due to narrow panel spans, leading to limited goafing and heightened abutment stresses on surrounding pillars and infrastructure. This necessitated additional support for strategic pillars to ensure long-term stability. To address these challenges, comprehensive research was conducted, which included back-analysis of stooped panels and numerical modelling. Findings revealed that goafing was influenced more by horizontal stress concentrators, such as geological structures than panel spans. Goafing at NDC has primarily been defined by low-angle shear failures, which only extend a couple of metres into the immediate sandstone roof. This is known as partial goafing, which typically results in high abutment stresses. Since complete goafing is unlikely due to the depth below surface and the competent roof material, the high abutment stresses needed to be managed by increasing the width of the barrier pillars between panels and leaving a sufficient number of stopper pillars at the end of a stooped panel. Numerical modelling was used to validate NDC's current design strategy of stooping panels and to determine the width of new barrier pillars. The derived strategy includes an increase in barrier pillar width and stand-off distances, to ensure the long-term stability of main developments. iv The current stooping strategy which was informed by comprehensive research and modelling, has proven effective in both safety and stability.Item Benefits of using Internet of Things technology for fuel management at a mechanised underground platinum bord and pillar mine: A Bathopele mine case study(University of the Witwatersrand, Johannesburg, 2024-01) Thema, Sephela Makete; Cawood, Frederick; Feroze, TariqThe advent of the fourth industrial revolution, Environmental Social and Governance (ESG), and push for green energy transition has propelled mining companies to reconsider their strategies. Over the past two decades, mining companies along the Bushveld Igneous complex in South Africa have been shifting towards mechanized mining methods which are generally safer and provide for the generation of greater volumes of output. Sibanye Stillwater’s Bathopele mine, which has a fleet of over two hundred and fifty (250) trackless mobile machinery (TMM) and a daily fuel consumption of approximately ten thousand (10 000) liters per day. The introduction of Internet of Things (IOT) technology in the fuel management system at Bathopele mine achieved benefits such as fuel consumption tracking, effective inventory management, prevention of fuel theft, detection of fuel leaks, determination of maintenance requirements and readily available access to fuel use data. This access to data enabled the mine to effectively apply for fuel use rebates from the South African Revenue Services (SARS) with ease. To determine the impact of the increased distance to underground working places on the refueling of TMM, the Theory of Constraints (TOC) method, qualitative and quantitative techniques were applied. A bivariate analysis conducted indicated a linear relationship between fuel consumption and production output at Bathopele mine, which suggests that an effective fuel management system had a positive impact on production output at the mine. A real-time or near real time model for fuel management in underground trackless bord and pillar mines in proposed.Item A comparison of various modelling techniques to optimise production rate on a platinum mining project(2021) Dreyer, JacoEvery business aims to create an optimal economic value for its shareholders. The production rate is one of the critical drivers of value in the mining business. Several approaches have been developed to determine the production rate for mining operations. This study applied three approaches for determining production rate, namely the tonnage-based, microeconomic and marginal-analysis modelling methods. These methods were applied on a platinum project, and the production rate results from the three methods were used to determine the life of mine (LOM) production profiles, capital expenditure (CAPEX) and operational expenditure (OPEX). These results were then used as inputs into a discounted cash flow (DCF) model. The DCF model results were compared and analysed to determine a production rate determination method that results in an optimum production output rate for the project. The study revealed that the tonnage-based modelling technique resulted in the highest production rate of 410-kilo tonnes per month (ktpm), the highest CAPEX of USD957.24 million, the lowest OPEX of USD75.37 per mined tonne, the highest net present value (NPV) of USD63.12 million and the highest internal rate of return (IRR) of 12.85% over a 40-year LOM. The microeconomic modelling technique ranked second with a production rate of 270 ktpm, CAPEX of USD 726.24 million, OPEX of USD 76.68 per mined tonne, NPV of USD 3.46 million and IRR of 10.17%. The marginal-analysis modelling technique ranked last with a production rate of 230 ktpm, CAPEX of USD 658.76 million, OPEX of USD 77.83 per mined tonne, NPV of USD -10.69 million and the lowest IRR of 9.47%. Mineral Resource tonnage-based modelling may be further investigated in other commodities other than platinum or other multi-element/polymetallic mineral deposits in line with the South African mining industry. This will result in the formulation of industry-specific calibration in the South African mining industryItem Developing a work management system to create an integrated and optimal short-term planning process at South Deep Mine(University of the Witwatersrand, Johannesburg, 2024) Maleka, ManuelThis research was conducted at South Deep Mine, an underground trackless gold mine located within the Modderfontein Farm in the Westonaria District, Southwest of Johannesburg. The aim of this study was to develop a work management system to create an integrated and optimal short-term planning process at South Deep Mine. The study employed both quantitative and qualitative research methods to achieve its objectives. Most of the data was obtained through an online survey which targeted individuals employed within the mine technical services department. The problem being addressed in this research is the challenge associated with manual data capturing during planning sessions. This research is driven by a desire to improve work efficiency and mine productivity at South Deep Mine through the application of innovative planning and reporting tools. Literature review presented the importance of innovation and effective planning in mining operations, indicating the role of integrated work management systems in modernized underground mining environments. Work Management Systems investigated were Deswik and MineRP software and Syncromine reporting system. The results reflected that Deswik and Syncromine are used throughout the industry with some benefits such as the ability to produce integrated production reports and the reliability in data handling. However, data analysis revealed shortcomings in existing work management systems, particularly in addressing real-time data and promoting automation. The aims of this research were achieved through the development of a systemized planning protocol. The study highlighted the need for an iv integrated approach to address short-term planning challenges. Future studies include the adoption of user-friendly software tailored with site specific requirements and the development of models covering all aspects of the mining value chain.Item Evaluating the economics of constructing mine haul roads using Portland cement stabilization- a case study at Lumwana Mine(University of the Witwatersrand, Johannesburg, 2024) Katukula, Brian; Birch, ClintonSurface mine operations engage in various strategies to optimise efficiency and productivity. The efficiency and productivity aspect of such operations aims to deliver the maximum amount of mined tonnes out of the open-pit using minimum resources. Efficiency and productivity entail that the means of conveying the material mined out of the open-pit must be at their best. In turn, equipment used in mining must be available in a good state. Furthermore, the road network and the bench conditions where such equipment operates in must offer minimum resistance for efficient utilisation. In this study, a means of improving the mine haul road condition was examined in which a ramp section at Barrick’s Lumwana Mine in North Western Zambia was stabilised with Portland cement to make it competent with an extended life span. The 300 m of Portland cement stabilised ramp section provided a common overlap of information before and after stabilisation. The information was then used as input for this study. The ramp was observed for data collection over six months, from June 2020 to December 2020. MaxMine, an independent fleet management and optimisation system, was used to collect truck-related information such as speed, time through the section, distance travelled, entry speed, the payload in tonnes, fuel consumption, and surface smoothness of the haul road section. An analysis of this information was able to deduce gains made in fuel usage, truck loaded haul and empty speeds, payload, and haul road smoothness. Information on the construction costs and other input parameters related to haul road maintenance was consolidated from the mine’s project office and used as input data. The research study deduced that cement stabilisation delivered value in the productivity and efficiency of the mine operation as there was a 12% increase in the haulage speed of loaded trucks and a 45% increase in the empty return leg. iv Even though the maximum allowable empty truck speed is 50 km/h on the mine haul roads, going down the ramp is restricted to 30 km/h and the recorded speed in the study of 34 km/h showed that a smooth ramp can be a source of safety violations. The mine has since installed a fleet management system to monitor and manage speed violations and invested in simulator training for its operators to ensure they drive the trucks within safe allowable speed limits using installed systems on the haul trucks such as the speed retarder and cruise controls. There was a 10% reduction in fuel consumption on the loaded haul and 14% on the empty return. There was also a corresponding payload increase of 5% from 243 tonnes to 255 tonnes for the review period. The increase in payload was within the capacity of the tyres to handle and had no negative impact on tyre life as the 53/80R63 tyres fitted on these trucks can handle more than 255 tonnes of payload. It is the same tyre specification used on a Hitachi 5000AC-3 dump truck that carries a nominal payload of 296 tonnes The ramp section in the research study delivered an overall value gain of over $306,000 despite incurring additional road construction costs of 13% above the normal. The additional construction costs were offset by the gains made on reduced haul road maintenance costs, which were reduced by 99.5%. Other gains made were on fuel consumption and truck maintenance through hours saved from truck speeds/cycle time gains.Item Geometallurgical influence of clays on the Jwaneng kimberlite value chain(2024) Nkgakile, NaomiGeometallurgy is a cross- disciplinary function that provides a better understanding of the ore characteristics impacting the treatability of the material. Optimal treatment of the material is enabled by understanding variability in the ore body. Having this understanding leads to flexibility when planning mining mixes. The present investigation of the Jwaneng DK2 deposit’s geometallurgical responses demonstrate that various rock lithologies impact the treatability of the Jwaneng kimberlites. The plan t is therefore hindered from achieving design capacity as a result of its treatability constraints. The volcaniclastic kimberlite, which is a majority- treated lithology at Jwaneng Mine, contains the highest volumes of smectite clays. These clays cause settling challenges resulting in higher consumption of processing materials. To allow for informed strategic planning, all vital treatability information on the clayrich kimberlites needs to be collected. The clay occurrence can then be incorporated into the creation of the geometallurgy model. Then the completed geometallurgical model can be utilised as a predictive tool for planningItem Impact of secondary rock-breaking equipment availability on mining plan in block cave mining(University of the Witwatersrand, Johannesburg, 2024) Pedro, MartinaIn 2018, the Angolan economy was ranked the third largest in sub-Saharan Africa, behind Nigeria and South Africa. This performance is mainly driven by oil production, which represents 50% of the country’s Gross Domestic Product, 95% of its exports, and more than 70% of government revenue, while diamonds represent only 5% of Angola’s exports. The Angolan Government has already invested US$ 260 million into the National Geology Plan (PLANAGEO), which concluded the geophysical aerial survey of the country’s mineral and geological potential in October 2023, putting the country in a better position for future investment. According to the African Diamond Council, it was reported in the Kimberley Process Certification System Statistics in 2021 that the diamond industry in Angola represented almost 1.2 billion Euros, with the contribution to the Gross Domestic Products at 1.6%, making Angolan diamonds the second most important export commodity. The socio-economic impact of the diamond sector has improved from 2016 to 2022, of which a value of US$ 29.58 million was contributed to the areas of education, health, sport, environment, culture, et cetera in local and surrounding communities through the Brilhante Foundation. The diamond mining industry in Angola was regulated by the Diamond Law enacted in 1994. Presently, Angola’s mining industry is subject to state regulation stipulated in the Angolan constitution—Law No. 31/11 of September 2011 (the Mining Code)—and various additional statutory and regulatory acts. In the past five years, under the newly appointed government of 2017, the 2018 Mining Code was amended. This report aimed to investigate whether Angola had fully developed its diamond mining sector to maximise revenue from the industry while also iv attracting more investors and generating socio-economic benefits for everyone, including its citizens. The methodology used in this research was a qualitative research approach. This involved the collection of primary data by interviewing experts in the diamond mining industry, and secondary data that relied on desktop studies of published and unpublished data from books, journals, abstracts, statistical data, and reports from the government gazette. The research findings unequivocally affirmed a positive response to this inquiry. The construction of the Saurimo Diamond Pole in the Lunda Sul Province—featuring seven fully operational polishing factories including Kothari, Stardiam, Kapu Gems, and the KGK factory—has generated employment opportunities and had a positive socio-economic impact within the region. The CEFOLAD Diamond training centre is currently equipping Angolan citizens with the necessary skills and tools to make meaningful contributions to the growth and sustainability of future generations. Angola is the sixth-largest diamond producer globally and is known for its high-quality gemstones. The annual production of rough diamond exports in Angola was 9.396 million carats, with an average of US$ 163 per carat and a gross revenue of US$ 1.56 billion in 2023. The Angola diamond industry employed 200 000 individuals in 2020. The Luele mine was inaugurated on November 10, 2023, in Lunda Sul Province, Angola, and it is expected to contribute an additional 5–7 million carats to the annual diamond sector. The mine currently employs 1 300 Angolan nationals. Based on the findings of this report, it is recommended that more geological investigation needs to be done in areas with visible geological potential in order to enhance and find new deposits which will eventually increase diamond production.Item Impact of secondary rock-breaking equipment availability on mining plan in block cave mining(University of the Witwatersrand, Johannesburg, 2024) Nyarela, Martin SphiweBlock caving is one of the massive mining methods that has become increasingly popular due to its low operating cost, improved safety, and high production output. The low operational cost is attributable to minimal blasting, which is only focused on secondary rock-breaking activities. Once caved, the material flows continually and is loaded from the drawpoint to the tipping areas using LHDs and other means, such as scraper winches. Different rock fragmentations register in the drawpoint as loading continues. The sizes range from fine to medium fragmentation and the undesirable oversized rocks that cause hang-ups and blockages. Blockages and hang-ups disturb the flow of material, which negatively impacts compliance with the mining plan and draw control schedule. The hang-ups are treated with secondary rock-breaking equipment to make drawpoints available for loading. However, if the mechanical availability of rock-breaking equipment is low, drawpoints remain idle beyond acceptable limits. Additionally, factors such as the availability of experienced miners to address challenging hang-ups, in instances where treated hang- ups remain unresolved as a result of treatment failure, and the prioritisation of adjacent draw points for loading to restore macro material flow, especially in cases of high hang- ups, can significantly contribute to longer idle periods as well. In this regard, this research aimed to understand the impact that secondary rock-breaking equipment has on the mining plan at the PMC block cave. The research conducted an empirical study of the Secondary Breaking Unit, which forms part of the Mining Operations responsible for all secondary rock-breaking activities at the Palabora Mining Company (PMC). The secondary rock-breaking equipment types that this study investigated include the Medium Reach Rigs, Water Cannons, and Mobile Rock-Breakers. A 52-week data obtained from PMC was used for this study, covering iv the period from January to December 2021. The data pertain to secondary rock- breaking equipment availability and utilisation, cave availability, loading compliance, downtime contribution factors, and in-situ grade. The correlation and regression analysis methods were used for the analyses of data to answer the research questions. In this study, the copper content derived from the mined tonnes and in-situ grade was used as a proxy for the mining plan and it excludes uncontrollable factors such as recovery, pricing, and exchange rates. Firstly, the study sought to determine whether the PMC’s Lift 1 block cave is behaving as predicted and it was concluded that it is. Secondly, the study sought to determine if there is a relationship between the mining plan, using the deviation from the mining plan, and cave availability and loading compliance respectively. It was established that the correlation between the deviation from the mining plan and cave availability was not strong enough whereas the correlation between the deviation from the mining plan and loading compliance was strong enough to derive a predictive equation which was validated. Thirdly, the research sought to establish the minimum acceptable rock-breaking equipment availability at PMC. It was found that the minimum acceptable availability was cautiously 60% based on the historical data. Fourthly, the research sought to determine the research strategy that can improve the rock-breaking equipment availability from the low of 42% in 2021 to at least 60%. The mine’s target availability is 65%. To achieve this, categories of downtime for MRR, MBR and WC with high impact were identified using the Pareto principle. The maintenance overrun downtime category which was one of those with a high-impact downtime was found to be common in all three equipment types with a combined duration of 10 695 hours or 44.4 days per operational equipment per year. In this regard, the Schedule Maintenance strategy was suggested.Item Impact of the mining charter on socio-economic development and mining investment attractiveness in South Africa(University of the Witwatersrand, Johannesburg, 2024) Meela, Princess Makone; Mutemeri, NelliaThe purpose of this study was to review the impact of the Mining Charter on socio- economic development and mining investment attractiveness in South Africa. The impact on socio-economic development was assessed by reviewing government compliance reports and Minerals Council of South Africa publications. The analysis of exploration budgets as a percentage of country Gross Domestic Product (GDP) was used to gauge the investment attractiveness of South Africa’s mining industry. A qualitative description was also conducted on mining codes and mineral policies of Canada, Australia, Brazil, Chile and five African countries (Ghana, Botswana, Tanzania, DRC, Zambia) to understand how these countries utilise natural resources to advance socio-economic developments. The study concluded that the Mining Charter has a positive impact on socio-economic development in South Africa. The research further revealed that globally, South Africa ranks relatively low in its exploration expenditure in terms of both absolute exploration budget and percentage of exploration budget to GDP. Findings of the international benchmarking study are that the requirements of elements of the Mining Charter are similar to other socio- economic development interventions observed in the assessed mining jurisdictions. The requirement of ownership of mining companies by local people is restricted to South Africa and the DRC. In Canada there is limited sharing-holding/profit-sharing for the benefit of the community where there is an agreement in place between the mining company and such community. These agreements are not imposed by law or mining policy. The research finding regarding the ownership element is significant in that it links to the problem statement of the research study wherein the requirement of ownership of mining companies by citizens (“black people”) is reportedly one of the main hindrances of mining investments in South Africa, as singled out by some of the iii mining executives. The recommendation from the study is that the South African Government should enforce empowerment deals where all shareholders are treated equally in terms of contributions and participation in the managing of a mining company. In line with other mining jurisdictions particularly in Africa, direct state participation could be considered as an option for meaningful economic participation of the South African Government, for the benefit of all South Africans.Item Improving grade estimation using machine learning: a comparative study of ordinary kriging against machine learning algorithms(University of the Witwatersrand, Johannesburg, 2024) Akpabio, AniekanThis study investigated the efficiency of machine learning (ML) methods in the accurate prediction of ore grades, placing them in direct comparison with the established Ordinary Kriging (OK) methodology, a mainstay in geostatistical analysis. Utilising a dataset from a complex platinum group elements (PGE) deposit, the research assessed a suite of ML algorithms—namely, Random Forest (RF), Decision Trees (DT), Support Vector Regression (SVR), and particularly 𝑘- Nearest Neighbours (𝑘NN). The latter is highlighted for its adeptness in assimilating spatial data correlations intrinsically, echoing the insights from Nwalia's analytical explorations. The research engages with detailed swath plot analyses, comparative metric evaluations, and a nuanced understanding of spatial continuity, to illustrate the distinct advantages and operational competencies of the models. 𝑘NN, with its reliance on local data proximities and non-parametric nature, alongside RF, with its ensemble-based approach, emerged as capable in point estimate predictions. These models adeptly delineated local grade variations, demonstrating a high degree of reliability to the observed data and outperforming the OK model in both precision and accuracy. Further, the study examined block estimate predictions, a cornerstone in practical mining and resource estimation, where both 𝑘NN and RF demonstrated a commendable ability to generalise predictions over larger spatial extents. This translates into significant potential for enhancing mineral resource estimation processes, tailoring them to the granular specifics of a given ore body, and refining block model accuracy to inform more strategic mining operations. While the results endorse the ML methodologies as robust alternatives to traditional geostatistical techniques, the research also highlights the nuanced nature of these predictions. Factors such as the ore body's heterogeneity, the appropriateness of the variogram model, and the interplay between prediction scale and algorithmic performance are examined, offering a critical lens through which the suitability of each method is assessed. iv The research suggests that while some models like LR and SVR are bounded by linear assumptions and hyperparameter sensitivities, non-linear models such as DT and RF can innately navigate the complex, multifaceted layers of geological data. The comprehensive evaluation extends to propose a novel set of performance metrics designed to capture the intricacies of grade prediction, thereby aligning closely with the operational demands and decision-making processes in the mining industry.Item Improving open pit mine economics through ultimate pit slope optimization: case study of Pickstone-Peerless mine(2024) Nyamande, PardonIn most open pit mining operations the need to create stable pit slopes and the influence of the overall pit slope on the economics of such an operation is highly appreciated. Despite such knowledge many open pit mines are designed with little or no geotechnical investigations being carried out so as to come up with an optimized pit slope in line with site specific conditions. This can lead to under or over estimating pit slope angles. Conservative (too gentle) slopes result in high stripping ratios therefore a high operating cost. Slopes too steep may result in slope failures, which may lead to high operating costs or premature mine closure. This project emphasises the importance of geotechnical investigations not only for safety reasons but for economic reasons as well. A case study of Pickstone Peerless mine was used. Geotechnical data was gathered through core logging and face mapping of the existing pit. The data gathered was then used for stability analysis employing empirical, kinematics, limit equilibrium and numerical modelling. Rocscience software packages were used for numerical based analysis. From the results obtained it was concluded that it is possible to steepen the current 52o overall pit slope angle of the Peerless pit by 1o without compromising stability at both bench and regional scales. This will be possible provided adequate slope management practices are put in place and adhered to. The steeper slope would have saved the mine more than 2,681,110 m3 of waste stripping, translating to in excess of $12,064,995.00 (USD) in financial savings for the existing pit. The steeper angle applicable to the current pit may not be appropriate to the pit extensions. Further geotechnical evaluations should be done on suitably positioned and spaced boreholes in the area of the extension, to verify the stability of steeper slopes in that area. The analysis done as part of this project was used to show that the current pit can be deepened by 5 m without a push back.Item Investigating the influence of burden response on fragmentation at Sishen Mine(University of the Witwatersrand, Johannesburg, 2024) Moabelo, Matshidiso Tlou; Non, Matsobane; Tholana, TinasheSishen Mine is an iron ore mine based in the Northern Cape, 280 km north- west of Kimberley. The iron ore is extracted through means of drilling and blasting which utilises explosives to fragment the rock. This method of rock breakage requires blastholes to be assigned a delay timing. At Sishen Mine this is done through burden response. The mine has a set of timing guidelines that indicate the burden response range for each geological domain. The main focus of the study was on the waste and ore domains, which are blasted using the same burden response of between 12 ms/m to 18 ms/m. The aim of the study was to investigate the relationship between burden response and fragmentation and whether these timing guidelines for the ore domain result in the mine’s preferred fragmentation size of between 230 mm and 1400 mm where X80 is 600 mm. The study also aimed to investigate the impacts of fragmentation on loading rates and to measure the DMS ROM lump to fine ratio during and after determining the optimal burden response for the ore domain. The investigation was done from March 2022 to December 2023. It was carried out on 18 blocks in the North and South Mine pits. The research found that in the ore domain, fragmentation sizes increase with faster burden response. The fastest burden response used in the study was 14 ms/m and yielded X80 of 354.63 mm. Furthermore, Powergel Eco 35 explosive product resulted in coarser fragmentation in the ore domain compared to Innovex EGA. It was also found that loading rates reduced with increasing fragmentation size. The DMS ROM lump to fine ratio improved during the duration of the investigation. In 2021, the average lump to fine ratio was 77.74% which increased by 1.69% to 79.43% in 2022 and by 3.76% to 81.50% in 2023 indicating that a faster burden response improved lump to fine ratio. Ore blocks should be blasted with a burden response faster than 14 ms/m and waste blocks with a burden response range of 16 iv ms/m to 18 ms/m. However, more studies should be conducted on burden responses faster than 14 ms/m. Powergel Eco 35 should be used to charge ore blocks over Innovex EGA. Sishen Mine should consider including inter- hole delay timing on the timing guidelines.Item Investigation of long-hole stope performance at south deep gold mine(University of the Witwatersrand, Johannesburg, 2024) Ncube, Musawenkosi GreciousSouth Deep Gold Mine is located 45km south west of Johannesburg within the gold-rich Witwatersrand Basin. The reefs at the mine occur within an economically significant stratigraphic bundle containing Ventersdorp Contact Reef (VCR) and Upper Elsburg conglomerate units. Long-hole stopping (LHS) is the primary method of mining and accounts for over 60% of the gold produced at the mine. It is, therefore, critical that the stopes meet the required production output for the designed mine lifespan at efficient stope turnaround times. However, mine data suggests that ore production from LHS has been erratic and has significantly affected the mine’s ability to produce to its installed capacity. The reduction in productivity and utilization is an area requiring research and this project investigated LHS performance at the mine to understand factors that influence stope turnaround time. Three research questions guided the study intending to improve LHS performance: • What is the influence of geological environments on LHS performance; • How do design aspects at South Deep affect LHS performance; and • How do current drilling and blasting practices affect LHS performance? To answer the research questions, the research adopted a stepwise process of categorising mining environments, analysing stope data files on Deswik software, developing predictive models on Python and MS Excel, informing excavation design, and finally reviewing drilling and blasting practices at the mine. These steps helped in leveraging the intersection that exists between geological environments, technical design aspects as well as operating tactics at the mine. iii The findings from the research questions led to the emergence of two themes. The first theme corresponding to the influence of geological environments and design aspects relates to the application of engineering principles in the mining environment, within the jurisdiction of the mining engineer / mine planner. The second theme, corresponding to drilling and blasting practices, relates to operational excellence, within the jurisdiction of the miner. The success of LHS performance hinges on the interplay and balance of these two themes. The major findings of the research indicated that deviation from set standards and malfunctioning components compromised drilling accuracy while wrongly charged holes (over-charged/under-charged) compromised blasting efficiency. They further showed that conventional and de-stress cut environment stopes were the most susceptible to over-break. Severe over-break was found on Secondary and Sequential stopes, predominantly on hanging walls and footwalls. Hanging walls and footwalls with hydraulic radius (HR) values above 6.0 (mine standard) also showed high susceptibility to over-break. In the process of analysing the results, the research developed a multi-variate model to predict the behaviour of the relationship between LHS performance and HR. It also created a matrix that informs how the mine may manage over-break. The research concluded by giving a set of recommendations for improving LHS performance, the chief of which emphasised the importance of strict supervision of drilling and blasting practices underground, measuring drilling against quality and quantity metrics as well as aiming for designing stopes with HR values below 6.0. It further recommended the adoption of the stoping scenario matrix developed, the improvement of the integrity of backfilling as well as the automation of the drilling and charging processes.