Research Publications/Outputs

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Communications and engagement tool for local suppliers and small, medium enterprises
(2023-06) Naidoo, P; Khan, Sumaya; Swettenham, T; Ramparsad, S
With mining modernisation, the awareness of communities' social and economic needs is important for a sustainable socio-economic environment. Meaningful engagement and communication with communities is critical. This project entailed the development of a communications and engagement tool for local suppliers and small, medium and micro enterprises to support localisation at mine communities and improve local procurement for local economic development. The tool development was informed by a literature review, data gathering, pilot studies and validation sessions. The tool is a web-based digital application that includes five features: checklists, frequently asked questions, notice board, resource library and query submission. The tool, a user-guideline and video were developed for potential use by South African gold and platinum group metal mines. The tool is not meant to replace current systems or processes at mines but rather to complement them. The tool is customisable, may enable decision-making and aimed at improving local procurement processes.
Community social-needs assessment tool
(2023-06) Likaku, Y; Pelders, Jodi L; Bull, S; Swettenham, T; Ramparsad, S
Mining, mining modernisation, and eventual mine closure have impacts on mine communities, and an understanding of community socio-economic needs is necessary. This understanding is further important for the conceptualisation of communities that are self-sustainable beyond the closure of mines. The aim of the project was to develop a community social-needs assessment tool for potential use by gold and platinum group metal mines. The project was informed by desktop research, literature review and stakeholder engagement, and the tool was developed for use and piloted with industry partners. The assessment tool that was developed comprises of questionnaires for small, medium, and micro enterprises, community members, community-based organisations and non-governmental organisations, a notice board, and a resource library of useful information. Implementation of the tool is expected to generate an improved understanding of community socio-economic needs towards shared value creation to support environmental, social and governance agendas.
Community social-needs assessment tool
(2023-06) Likaku, Y; Pelders, Jodi L; Bull, S; Swettenham, T; Ramparsad, S
Mining, mining modernisation, and eventual mine closure have impacts on mine communities, and an understanding of community socio-economic needs is necessary. This understanding is further important for the conceptualisation of communities that are self-sustainable beyond the closure of mines. The aim of the project was to develop a community social-needs assessment tool for potential use by gold and platinum group metal mines. The project was informed by desktop research, literature review and stakeholder engagement, and the tool was developed for use and piloted with industry partners. The assessment tool that was developed comprises of questionnaires for small, medium, and micro enterprises, community members, community-based organisations and non-governmental organisations, a notice board, and a resource library of useful information. Implementation of the tool is expected to generate an improved understanding of community socio-economic needs towards shared value creation to support environmental, social and governance agendas.
Cost-effective in-mine seismic experiments to image platinum deposits and associated geological structures at Maseve platinum mine, South Africa
(2022-05) Rapetsoa, MK; Manzi, MSD; Westgate; Sihoyiya, M; James, I; Onyebueke, E; Kubeka, P; Durrheim, RJ; Kgarume, Thabang E
The detection of mineral deposits and their related geological structures is of great importance to the mining industry as structures (such as dykes and faults) can affect the safety, cost and efficiency of mining. With the goal of testing cost-effective seismic methods for mineral exploration and mining, active and passive seismic experiments were conducted at Maseve platinum mine in the Bushveld Complex (South Africa) in 2020. The experiments involved surface-passive (using 5 Hz wireless nodes; single vertical component) and in-mine active reflection seismic surveys (using 4.5 Hzland streamer and 5 kg sledgehammer) to image geological structures and delineate economic platinum-group elements bearing Merensky and Upper Group-2 chromitite layers (known as reefs). This paper presents only the results from the in-mine active seismic experiments. The in-mine seismic surveys consisted of seven 2D reflection seismic profiles in the development tunnels, which were located ~550 m below groundsurface and a few tens of metres above known mineralizations: the Upper Group-2 and Merensky Reef. The data were carefully processed to enhance the reflections and suppress noise generated by mine infrastructure (e.g., equipment and ventilation). We successfully imaged the Merensky Reef and Upper Group-2 orebodies approximately 55 m and 124 m below the tunnel floor, respectively, and delineated faults and dykes that crosscut them. Furthermore, the seismic data reveal relatively strong amplitude and faulted reflections below the Upper Group-2 that may represent deeper chromitite-enriched orebodies. However, the economic value of these horizons canonly be confirmed through drilling. The processed seismic data were combined with borehole data, synthetic modelling and geological models to constrain the interpretation. This study encourages the use of in-mine seismics for future mineral exploration, mine development and planning.
Deep-level Gold and Platinum Mining - The Application of Geophysics in South Africa
(Springer, 2022-08) Van Schoor, Michael; Nkosi, Nomqhele Z; Magweregwede, Fleckson; Kgarume, Thabang E
This book provides the basic know-how and guidance to effectively exploit non-destructive geophysical technologies and apply them in the underground mining environment to optimise mineral extraction and to contribute to safer mining. The effective application of these technologies can enable a better understanding of the unseen orebody and the surrounding rock mass ahead of the mining face; the potential benefits of applying in-mine geophysics is demonstrated through a selection of case studies conducted in deep-level hard rock mines in South Africa. This book also offers valuable insight and training material for students in a variety of relevant mining disciplines like geology, rock engineering, mining engineering, mine planning and mineral resource management.
Development of Best Practice Guideline for the management of hot holes in surface coal mines
(2024) Mpofu, Mvikel; Maphalala, M; Kgarume, Thabang E; Magweregwede, Fleckson T; Stenzel, G
Surface coal operations in which mining activities are conducted above old underground workings experience hot holes after drilling. In a coal mine, hot holes are defined as shot holes, which after being drilled have an in-hole ambient temperature of 40°C or above or show a temperature increase of 3°C or more during monitoring. Hot holes and other cavities, such as cracks, pose health and safety risks to workers, such as exposure to hot air and high concentrations of noxious gases released from these holes. In addition, workers may be exposed to premature detonation of explosives caused by in-hole temperature increases and chemical reactions. To this end, Coaltech Research Association commissioned a project to develop a Best Practice Guideline for the management of hot holes. This paper is a compilation of the activities conducted in the development of the Best Practice Guideline between 2021 and 2022. The activities included a review of standard operating procedures and hot-hole temperature-measuring and -monitoring devices, and the assessment of current hot-hole procedures at selected mines. The results indicated that management of hot holes requires a focus on pre-emptive risk assessment of mining blocks, identification of hot holes using the correct temperature-measuring devices, and continuous monitoring of hot holes from the time of drilling until just before blasting. Hot-hole management accessories, such as polyvinyl chloride sleeves, were found to be effective in insulating the hot-hole emulsion from the rock mass temperature, thus preventing the potential for premature detonation.
Experimental and in-situ physical properties measurements from a seismogenic zone in a deep South African mine
(2022-09) Nkosi, N; Manzi, M; Roberts, David P; Durrheim, R; Ogasawara, H; Ziegler, M; Liebenberg, B; Onstott, T
Since the 1990s, South Africa has experienced several sizeable earthquakes occurring in mining regions at depths ranging between 2 km and 4 km below the surface. These consist of the Welkom (ML 4.2) and Stilfontein (ML 5.3) earthquakes, which occurred in 1990 and 2005, respectively. The occurrence of these seismic events resulted in the destruction of mine infrastructure and some cases the death of miners. More recently, the 2014 ML 5.5 earthquake, which occurred in the Orkney mining district, in the Witwatersrand Basin, is the largest event to occur in a mining region in South Africa (Figure 1). Although mining-related seismic events are common in South Africa (ML<2), the large magnitude and shallow hypocentral depth (~5 km) of this earthquake raise concern for future large events occurring at active mining levels and their potential to negatively affect mining operations. Additionally, the physical properties of the rocks around the active rupture zone are not well understood because no boreholes had been drilled at depths in and around the aftershock zone. Therefore, no meaningful correlations of the lithological units with physical properties obtained from experimental and in-situ measurements have been done.
The influence of stemming practice on ground vibration and airblast
(2021-01) Mpofu, Mvikel; Ngobese, Sibusiso SG; Maphalala, B; Roberts, David P; Khan, Sumaya
This paper details an assessment of stemming practices at a South African opencast coal mine and their influence on ground vibration and air blast. Quantitative and qualitative analysis methods were used for the study. The parameters assessed for the quantitative analyses included stemming length, stemming material type, blast-hole depth, burden, and spacing. Pre-blast data from the mine was analysed to determine the deviation between actual and mine design stemming parameters. Mine design stemming length was also compared to the rule-of-thumb stemming lengths. Peak particle velocity (ground vibration) and air blast data from seismograph stations around the mine was analysed to determine the correlation between stemming length and excessive ground vibration and air blast. The qualitative analysis involved observations of blasting procedures at the mine to determine compliance with mine procedures. Some level of non-compliance of actual stemming parameters to design stemming parameters was found, which initially suggested that non-compliance may have contributed to excessive air blast. However, further analysis of the seismograph results indicated no direct correlation between stemming length and excessive air blast and ground vibration. Since stemming parameters are interrelated, it is crucial that all blasting procedures, including stemming, are executed in accordance with best practice, and recorded accurately. There is a need for digital systems for capturing on-bench blasting parameters, as the currently used manual data recording and reporting systems are inefficient and prone to error. Improvements to blast designs are possible through efficient and accurate data recording and reporting systems.
Integration of in-mine seismic and GPR surveys to gain advanced knowledge of Bushveld Complex orebodies
(2023-08) Onyebueke, EO; Manzi, MSD; Rapetsoa, MK; Kgarume, Thabang E; Westgate, M; Durrheim, RJ; Pienaar, M; Sihoyiya, M; Mpofu, Mvikel; Van Schoor, Michael
Improving the exploration of deep-seated mineral deposits and assessing the stability of the mine pillars require that geophysical techniques are deployed in a fast and cost-effective manner with minimal environmental impact. This research presents results from in-mine reflection seismic experiments and a ground penetrating radar (GPR) survey conducted at the Maseve platinum mine, South Africa. The research aims to develop and implement methods to image platinum group metal (PGM) deposits and geological structures near mine tunnels and assess the stability of pillars. The seismic experiments were conducted using a sledgehammer source (10 lb), conventional cabled geophones (14 Hz), and a landstreamer with 4.5 Hz vertical component geophones. The GPR survey was conducted using a Noggin 500 GPR system with 500 MHz centre frequency. An image of the underlying orebody and geological structures down to 100 m from the mine tunnel floor (~500 m below ground surface) was produced. We correlated the coherent reflections beneath the tunnel floor with a known Upper Group (UG2) PGM orebody. The final seismic section shows that the UG2 mineralisation is dissected by near-vertical dykes, faults and fractures. These structures, faults in particular, are interpreted to have been active post-mineralisation, implying that they may have contributed to the current complex geometry of the deposit. Four GPR profiles were collected around a stability pillar adjacent to the seismic lines. The radargram sections were processed to improve the signal-to-noise ratio (S/N). The results show different patterns of fracturing and stress-induced structures. These fractures were shown to be sub-vertical and, possibly, constitute complex micro-structures within the pillar, which could compromise the pillar stability and integrity. The study demonstrates that in-mine seismic and GPR surveys can be cost-effective and valuable for mineral exploration.
Mitigating the rock fall and rockburst risk in South African gold and platinum mines through advanced knowledge of the ore body
(2023-10) Pienaar, M; Durrheim, RJ; Manzi, MSD; Nwaila, GT; Grobler, HCI; Kgarume, Thabang E; Pretorius, Dean D; Van Schoor, Michael; Oberholster, AJ
The Mandela Mining Precinct was launched in 2018 with the goal of modernizing the South African mining industry. It comprises three major initiatives that seek to improve efficiency, health and safety in current mining operations; develop fully mechanized systems to mine narrow tabular ore bodies in hard rock; and develop non-explosive rock-breaking systems. The crosscutting Advanced Orebody Knowledge (AOK) program seeks to develop technologies to characterize the rock mass ahead of mining and identify potentially hazardous geological features. Mining methods, layouts and rock support systems will be adjusted accordingly to mitigate the risk of rock falls and bursts. Technologies include rock drilling, light detection and ranging (LiDAR), ground penetrating radar (GPR), electrical resistance tomography (ERT), and various acoustic, thermographic and seismic techniques. Machine learning methods are being implemented to improve data processing and interpretation. This paper describes the status of the research program at 31 May 2023.
Optimization of shift cycles in the South African mining sector
(2021-08) Pelders, Jodi L; Magweregwede, Fleckson; Rupprecht, SM
Increased depths of conventional gold and platinum mines, longer travelling times as working places move further from the shaft, and ancillary activities taking place in the mining cycle reduce the useable time spent at the workface. Current shift lengths of 8 hours 20 minutes may no longer be adequate to complete required mining activities. The impact of mineworker commuting times on shift work is also not well understood. The aim of this research was to draft a framework to optimize shift cycles in order to maximize productivity, health, safety, and wellness in the South African mining sector. The framework was informed by a review of the literature, case studies at a local gold mine and platinum mine, and a workshop with industry experts. The findings indicate potential advantages of extended shift lengths and continuous operations, such as improved productivity, asset utilization, and employee morale. However, concerns included fatigue and the associated safety hazards, particularly when working longer shifts, night shifts, and numerous consecutive shifts. Job demands, personal factors, and commuting times are further considerations when scheduling shifts. The ideal shift system for the mining sector should holistically consider and balance operational requirements, health and safety, and employees’ and their families’ requirements, and suit the unique needs of each operation. Changes in shift cycles will require a structured change management process, which involves all stakeholders, and could help to enhance the viability of the South African mining sector.
Physical property studies to elucidate the source of seismic reflectivity within the ICDP DSeis seismogenic zone: Klerksdorp goldfield, South Africa
(2022-07) Nkosi, Nomqhele Z; Manzi, MSD; Westgate, M; Roberts, Dave; Durrheim, RJ; Ogasawara, H; Ziegler, M; Rickenbacher, M; Liebenberg, B; Onstott, TC
Petrophysical properties of cylindrical core specimens from three boreholes from the International Continental Scientific Drilling Program, the DSeis project, measured at ambient pressure and room temperature conditions in various laboratories are presented and compared with downhole petrophysical data (sonic and density). The measured properties are from sixty-six rock specimens constituting metasediments, metabasalts and intrusives. Seismic velocities were measured using 0.5 MHz P- and S-wave transducers. To investigate the source of seismic reflectivity observed on the 2D legacy seismic data, we computed synthetic seismograms for adjacent rock units using downhole petrophysical data and compared them with seismic reflections from the reflection seismic profile. The experimental measurements show that the metasediments exhibit lower bulk densities and seismic velocities than the metabasalts and intrusive specimens. The porosity was found to be less than 2% for all the samples. No clear trends emerge when the Poisson's ratio is plotted against the P-wave velocities and porosities of the samples. A positive relationship is observed between the bulk modulus and P-wave velocities of the rock samples. The highest calculated reflection coefficients (RC) are associated with the metasediment-intrusive interfaces in all three boreholes. The intrusive-metabasalt and the metasediment-metabasalt interfaces exhibit low RC. Synthetic seismograms reveal strong reflections that coincide with high RC calculated using the bulk density and velocity data. The synthetic seismograms also revealed additional strong reflections that were not identified using the reflection coefficients calculated from the rock specimens, due to core loss in some lithological units. Successful correlations are carried out between the synthetic seismic data and the real seismic data, enabling us to correlate the stratigraphic sequence drilled in the boreholes to the seismic reflections observed on the legacy 2D reflection seismic data.
Selected case studies in Engineering Geophysics
(2022-11) Van Schoor, Michael; Turnbull, TV; Maphalala, B
All geophysical methods have a specific niche application(s); however, some methods are more versatile than others and are applicable to a wider range of earth science problems. This is particularly true in the case of the GPR method, which is known to provide technical solutions in a diverse range of fields that include mining, hydrogeophysics, and engineering. This paper provides selected case study examples that illustrate the versatility and value of GPR within the field of engineering. Examples of specific applications of GPR in the engineering field include: Mapping reinforcing steel structures in concrete, Locating old foundations and building structures, Locating/tracking utilities, Mapping tree roots that threaten infrastructure, Characterising sinkholes, voids and subsidence, and Studying the integrity of concrete structures.
Stakeholder inclusion in the design and development of equipment for the modernizing mining sector in South Africa
(2023-04) Ngobese, Sibusiso S; Pelders, Jodi L; Botha, W; Magweregwede, Fleckson; Schutte, I
A people-centric, systematic approach that involves different stakeholders is considered necessary to successfully address changes associated with modernizing the South African mining industry. In this paper we discuss the inclusion of various South African mining industry stakeholders, particularly the employees, in equipment design and development processes. Data was acquired through a literature review and inputs from South African mining industry stakeholders through focus group discussions, interviews, and an online survey. It was suggested that some of the areas that could be improved by the inclusion of employees in the process are design quality, ergonomics, equipment acceptance by the workforce, safety, efficiency, skills, insight into context of use, and early design iterations and identification of problems. Among the issues considered to be barriers to inclusion were lack of buy-in, lack of resources, difficulty in manufacturers accessing the mines, difficulties in involving too many people, intellectual property concerns, and unavailability of mine employees due to their key responsibilities. Identified critical factors in the equipment design and development process include iterative design, stakeholder participation throughout the process, needs analysis through consultation, and change management. A guideline was developed for worker inclusion in equipment design and development that could be used by the South African mining industry. The study identified several economic and social benefits of including stakeholders in the early stages of design and development. It is recommended that the South African mining industry considers using the developed guideline.
Worker inclusion in equipment development processes in the modernizing minerals sector in South Africa
(2021-02) Pelders, Jodi; Schutte, S
Worker participation in equipment development can result in improved user acceptance and product quality. This paper focuses on worker engagement in equipment development processes in the South African minerals sector. Qualitative data was gathered during interviews with original equipment manufacturers (OEMs) and industry experts. A lack of inclusion in equipment design from workers from all organizational levels in mines was reported. Meanwhile, the historical context and workplace culture of the mining industry (including leadership, trust, training, performance, and remuneration factors) were evident barriers to the implementation of new technology. Worker engagement processes should include securing management commitment, creating multidisciplinary teams, effective facilitation, shared understanding of needs, training and development, and iterative design. Human-centred design approaches and independent platforms for engagement on equipment design requirements are recommended.

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