Research Articles
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For information on accessing School of Mining Engineering Research Articles content please contact : Salome Potgieter by email : salome.potgieter@wits.ac.za or Tel : 011 717 1961
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- ItemTowards safer mining: Scientific measurement approaches that could be applied for imaging and locating the buried container lamp-room at Lily mine.(The Southern African Institute of Mining and Metallurgy., 2018-02) Hussain, I; Cawood, F.T.; Ali, SWhen the crown pillar at Lily mine collapsed on 5 February 2016, a lamp-room in a container on surface was engulfed in the sinkhole that formed, trapping three miners who were in the lamp-room at the time. In situations like this, it is imperative to locate and rescue the missing miners before the window of opportunity to find them alive closes. The Wits Mining Institute (WMI) at the University of the Witwatersrand was requested to assist with suggestions, and a conceptual study was undertaken to identify techniques that were likely to be successful. Several techniques that have the potential to locate the position of the container were identified, but the typical noise in the form of steel objects, mine cavities, and a combination of broken and solid rock in a complex geographical and geomechanical environment will pose significant challenges.
- ItemA survey of applications of multicriteria decision analysis methods in mine planning and related case studies.(The Southern African Institute of Mining and Metallurgy., 2016-11) Mahase, M.J.; Musingwini, C.; Nhleko, A.S.In an environment like the mining industry, which is characterized by different stakeholders with multiple objectives, multi-criteria decision analysis (MCDA) is a useful approach for optimal decision-making. The application of MCDA techniques in the mining industry has predominantly been in mine planning and related problems, although no comprehensive survey has previously been undertaken to establish the application trends. A survey of the use of MCDA techniques was therefore conducted using case studies from the literature. It was noted that often two or more methods are applied to the same problem in order to increase confidence in the solution derived. As the number of criteria and alternatives increases, some methods become inefficient. A combination of the analytic hierarchy process (AHP) method with other MCDA techniques was the most frequently used approach, indicating the efficiency of the AHP method, especially when evaluating problems with more criteria and fewer alternatives. A combination of fuzzy theory with AHP or other methods incorporates uncertainty. The findings from the survey will benefit users applying MCDA techniques to solve mine planning and related problems.
- ItemJust-in-time development model for a sub-level caving underground mine in Zimbabwe.(The Southern African Institute of Mining and Metallurgy., 2003-04) Musingwini, C.; Minnitt, R.C.A.; Phuti, D.; Makwara, F.Traditionally, mineral reserves management at most underground mines in Zimbabwe focus on maintaining large mineral reserves so that the time between development and production is as long as possible. Historical data at Shabanie mine, a Zimbabwean sub-level caving underground mining operation, confirms this practice. However, the high cost of underground development means that the luxury of large buffer mineral reserves cannot be justified. Furthermore significant increases in the costs of production, exacerbated by the current unfavourable economic climate, make the wisdom of extending development workings well ahead of use questionable. Poor ground conditions at Shabanie mine, mean that some development ends have to be re-mined two or three times due to partial or complete closure between the time they are mined and the time they are utilized. In order to reduce the inordinately high support costs associated with closure of development ends a new 'Just-in-time' (JIT) approach that provides development ends as and when they are needed, has been adopted. Accordingly a model to determine an appropriate 'just-in-time' rate of development has been created. The JIT development model indicated that the mine could reduce development rates from 330 m/month in 2001, to 160 m/month in 2002 and achieve savings of about 50% on annual support costs, but still assure customers of a long-term product supply. The mine accepted the model in November 2001 and began implementing it in 2002. Results of the implementation will be reviewed in 2003.
- ItemFirst cycle experience of a business process re-engineering programme at Shabanie Mine.(The Southern African Institute of Mining and Metallurgy., 2005-04) Musingwini, C.; Muzoriwa, C.; Phuti, D.; Mbirikira, D.In the past ten to fifteen years, many organizations have applied business process re-engineering (BPR) to significantly improve their business competitiveness or stave off closures. The mining industry in Southern Africa is no exception and documented examples can be drawn from South Africa. Although the concept is superficially simple, its application has been marked by a high failure rate of about 70 per cent because it has been generally misunderstood. Shabanie mine, a chrysotile asbestos fibre producer in Zimbabwe took cognisance of this fact by cautiously embarking on a modular BPR programme in October of 2002. A year was used as a complete cycle or module for re-evaluation of the programme. Shabanie mine adopted BPR as part of management efforts to remain competitive amid serious threats to operational viability. These threats included hyper-inflation driven rising production costs, a declining world asbestos market and a possibility that Russia could take over the shrinking world asbestos market by dumping low-priced asbestos fibre. The only competitive advantage that the mine had was the high quality of its long-fibre chrysotile asbestos. The major BPR thrust was therefore to redesign processes for improved productivity and ultimately achieve a lower cost per ton of final asbestos fibre product. In addition, corporate culture change and cost-saving were also factored into the programme. This paper discusses the implementation experience of the BPR programme at the mine. The main BPR beneficial highlights are improved productivity, sizeable cost-savings, positive corporate culture change and identification of secondary projects. One of the lessons learnt from this programme is that mining companies will have to deal with the HIV/AIDS pandemic if they are to sustain high levels of productivity into the future.
- ItemTechnical operating flexibility in the analysis of mine layouts and schedules.(The Southern African Institute of Mining and Metallurgy., 2007-02) Musingwini, C.; Minnitt, R.C.A.; Woodhall, M.Often overlooked factor in the analysis of mine layouts and schedules is technical operating flexibility (or tactical flexibility), mainly due to its nebulous nature. By glossing over technical operating flexibility the resultant mine layouts and schedules may be suboptimal. The need to incorporate technical operating flexibility into the analysis and comparison of mine layouts and schedules is increasing in importance. The nature of technical operating flexibility is illustrated, previous work on valuing of operating flexibility reviewed, and a proposal made on how technical operating flexibility can be quantified for tabular reef mines by using a platinum reef deposit as a case study. Once technical operating flexibility has been quantified it becomes possible to explore its incorporation into the analysis of mine layouts and schedules and subsequent optimization processes. This paper is a revised version of a paper presented in the Proceedings of the Second International Platinum Conference, 'Platinum Surges Ahead' in 2006. The work described in this paper is part of a current PhD study at the University of the Witwatersrand.