WIReDSpace
Welcome to WIReDSpace(Wits Institutional Repository on DSpace)
For queries relating to content and technical issues, please contact IR specialists via this email address : openscholarship.library@wits.ac.za, Tel: 011 717 4652 or 011 717 1954
Communities in WIReDSpace
Select a community to browse its collections.
- This community is for all faculties and schools' theses and dissertations by masters and doctoral students.
Recent Submissions
The Impact of Digital Technology in South African Coal Mining: A Financial Performance Analysis of Anglo Coal American, Bhp Billiton and Glencore
(University of the Witwatersrand, Johannesburg, 2023-10-27) Maluleke, Reply; Neingo, Paskalia; Marshall, Tania R.
Digital technology, typically, refers to electronic tools, resources, devices and systems that store, generate and process information rapidly. Digital technology and innovation are among the initiatives that can assist mining companies to realise productive, efficient, profitable and sustainable mines. As such, the mining industry is taking steps towards digital technology and innovations that have evolved in recent years. The objective of this report was to discuss the financial impact of digital technology of the selected South African thermal coal mining companies namely Anglo American Coal Division now operating as Thungela Resources, Glencore, and South32, previously spun out of BHP Billiton and now operating as Seriti Resources. Coal mines were selected for analysis, due to their importance with respect to energy generation in South Africa. Industry cost curves over the period 2013-2019 were constructed as part of the financial analyses to show the trend of the selected companies’ unit costs. The research also used other financial analysis methods such as operating profit, profitability ratios, Economic Value Add and Du Pont analysis to analyse the performance of these companies. There appeared to be no production and unit cost improvement directly linked with investment in digital technology, as breakdowns, commodity prices, depletion of reserves, selling of operations, mine closures, high contracting prices, inflations and other factors also affected these parameters. Results for Anglo Coal and South32 did not indicate consistent good or improved financial results in all the financial analysis methods post the investment years in digital technology, in contrast to Glencore’s results which did. Glencore also invested more capital in digital technology as compared to Anglo Coal and South32. It is suggested that this may be one reason for its success. Consequently, it is recommended that companies looking to invest in digital technology follow the example of Glencore and invest as much capital as possible in this venture in order to maximise its potential.
Verifying the Quality and Performance of Grout Using Sensor Technology
(University of the Witwatersrand, Johannesburg, 2023-10) Hadebe, Menzi Bright; Mitra, Rudrajit
Underground mines systematically install ground support to stabilize excavations and provide safe working environments. Support units, such as rock bolts and cables, are commonly filled with cementitious grout to effectively prevent corrosion, maintain bonding behaviour between the support unit and grout, and enhance the load transfer between the grout and surrounding rock mass. The grouting process is however time consuming and labour-intensive, which leads to haphazard installations. These substandard grout installations are only observed after rock fall instabilities occur when the quality and extent of grouting inside a support hole are exposed and can be observed. The need to monitor grout installations increased (provide assurance) but remained a challenge due to the invisibility of grout inside the support hole. The invisibility of the grout column inside the support hole renders the routine quality control inspections of installed support units ineffective. This ineffectiveness of quality control inspections has led to a growing need to monitor grout installations with smart technologies to provide quality assurance of full-column grouting. In its current state, grout technology in the mining industry can only measure the extent of grout inside a support hole directly after installation (limited battery life). It cannot measure the loss of grouting material into near borehole fractures, shrinkage, quality of grout inside the support hole or its impact on support performance. These factors are critical to the success of an effective support system and pose a significant safety risk when overlooked. This research report will describe how grout sensor technology data was recorded and used to verify the extent and quality of cementitious grout inside support hole installations at laboratory and deep-level mine study sites. Grout sensor technology, in practice, utilizes several grout sensors placed at predetermined positions along a support unit with a receiver attached to the collar of the support hole. Electrical resistivity data from each sensor is collected using a grout detector. Depending on the position of each grout sensor, the extent of grout inside a support hole can be confirmed, hence eliminating the need for speculative and ineffective visual observations. The non-destructive verification and prediction of the quality and performance of grout inside support holes using sensor technology forms an invaluable strata control tool that can be used to identify sub-standard grouting operations and significantly improve safety at underground mines. This novel and innovative technology is a mining industry first.
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, Tariq
The 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.
The Development and Application of a Hybrid Metaheuristic Clustering Algorithm to the Capacitated Vehicle Routing Problem
(University of the Witwatersrand, Johannesburg, 2023-11) de Sousa, Andrea Vaz; Bührmann, Joke
The Vehicle Routing Problem (VRP) is an important combinatorial optimization problem in the field of operations research that remains a significant challenge for distribution and logistics operations globally. This research is concerned with a relatively simple variation of the VRP referred to as the Capacitated Vehicle Routing Problem (CVRP), and it focuses on the integration of metaheuristics into its solution. A Genetic Algorithm (GA) was selected and integrated into several CVRP solutions with various configurations of the algorithm. Additionally, a hybrid implementation was proposed, which augments the GA by incorporating conventional heuristics to seed the initial population with “good” solutions. The proposed hybrid solution was the best performing solution evaluated and yielded results comparable to the best-known solution for the smaller datasets. However, the solution quality with respect to the best known solutions decreased with an increase in the size of the problem. This may be attributed to premature termination of the algorithm. Overall, the solutions evaluated were not able to match the best-known solution for each dataset, however successive improvements in the results suggest that GAs are effective at solving the CVRP. Moreover, combining metaheuristics with other methods is also an effective strategy for improving the efficiency of the solution space exploration.
An Investigation of Factors Contributing to Long Waiting of Patients Collecting Repeat Medication in a Tertiary Hospital Pharmacy
(University of the Witwatersrand, Johannesburg, 2023-02) Oladipupo, Rekgopetse Victoria; Hattingh, Teresa; Sunjka, Bernadette
According to the World Health Organization (WHO) patient waiting time is identified as a key measurement to a responsive healthcare service and is an important indicator of quality of services offered by hospitals (NDoH, 2011) as it affects the patient’s responsiveness to the services received (NDoH, 2011; SA FAM PRACTICE, 2008; Tegabu, 2008; Pandit et, al. 2016). Long waiting times at healthcare facilities undermines the services rendered resulting in compromised or unfulfilled patient care (Afolabi & Erhun, 2003). This research studies the processes associated with the collection of repeat medication in a tertiary hospital pharmacy in order to identify value adding activities and non-value adding activities that could be impacting patient waiting time using the Lean thinking concept of driving out waste. A qualitative observational method was therefore employed to observe all the steps involved during the journey of the patient collecting repeat medication from the registration point until medication was issued at the pharmacy. Value stream mapping (one of Lean Thinking principle) was employed to analyze the processes that took place. Patient waiting time was also measured from the registration point to the pharmacy. On average patients had to wait a total 159 minutes before they could access services both at the registration point (67 minutes) and at pharmacy (92 minutes). The service time was 29 minutes at both registration point (11 minutes) and pharmacy (18 minutes). Of the 18 minutes pharmacy service time; eight minutes were found to be value-adding while 10 minutes were non-value-adding mainly due to prescriptions waiting on queue to be picked, waiting to be signed by the pharmacist and waiting to be issued out to the patient. Lack of a dedicated pharmacy service points exclusively for chronic repeat patients, manual dispensing, illegible doctor’s prescriptions, were found to prolong the time it takes the Pharmacist to complete a prescription. Post Basic Pharmacist Assistants performing duties that could be performed by a less qualified staff (e.g., Learner Basic Pharmacist Assistants) during peak hours was not value adding and thus decreasing productivity. The level of staff commitment in addressing issues of quality such as long waiting time was questionable. The demand / workload and capacity during the early hours of business at the registration point did not seem to match, thus resulting in bottlenecks at the patient registration point and throughout the system.