Research Outputs (Mining Engineering)

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A 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.
Techno-economic optimization of level and raise spacing in Bushveld Complex platinum reef conventional breast mining.
(The Southern African Institute of Mining and Metallurgy., 2010-08) Musingwini, C.
The Bushveld Complex is economically significant and strategically important to South Africa, thus it is imperative that optimal extraction of platinum group metal (PGM) resources on the Bushveld Complex is achieved. Optimal extraction broadly requires that the maximum amount of ore is extracted by excavating and hauling the minimum amount of waste in the shortest possible time, at the least cost, and in the safest and most environmentally acceptable manner. In open-pit mine planning this entails among other things, minimizing the waste stripping ratio, whereas in underground mine planning it includes minimizing the metres of waste development In conventional mining, the main development that is in waste or partly in waste and defines the mining grid pattern, includes levels and raises. It was prudent to consider optimizing level and raise spacing in conventional mining because the method is a prevalent mining method on the Bushveld Complex accounting for nearly 70% of platinum production. The techno-economic optimization of level and raise spacing is characteristically a multi-criteria decision analysis (MCDA) optimization process and should therefore be analysed using MCDA techniques. The analytic hierarchy process (AHP) was the most appropriate MCDA technique for this research study. By using an orebody code named OB1 based on real geological data that was typical of Bushveld Complex platinum reef deposits, the derived optimal range of vertical level spacing was 30 m-50 m, and the optimal range of raise spacing was 180 m-220 m. The research methodology used in this study and the results obtained were received positively by the South African platinum mining Industry because for the first time in several decades, a holistic methodology and practically acceptable solution had been developed for the controversial debate of optimizing level and raise spacing for conventional mining.
A review of optimal planning of level and raise spacing in inclined narrow reefs.
(The Southern African Institute of Mining and Metallurgy., 2010-08) Musingwini, C.
The subject of optimal planning of level and raise spacing for inclined narrow reef deposits has received intermittent attention over the years because the subject matter is inherently complex. Previous work has approached the problem as simply that of simultaneously minimizing the total excavation and haulage cost associated with the development workings. However, when level and raise spacing are altered, other factors such as productivity are negatively affected, thus requiring a delicate trade-off of contradicting planning or optimization criteria. The paper concludes that the problem is actually of the multi-criteria decision analysis (MCDA) type, contrary to traditional thinking that the planning problem is achieved solely by minimizing waste development.
Empirical correlation of mineral commodity prices with exchange-traded mining stock prices.
(The Southern African Institute of Mining and Metallurgy., 2011-07) Nangolo, C.; Musingwini, C.
Mineral commodity prices comprise one of the key criteria in the selection of mining stocks. We contend that of the three principal elements of mineral commodity prices, spot price, forward price and long-term price, one has a greater impact on the share valuation processes used by investors. This research paper examines the extent to which each of these elements influences the valuation process. The intention is to provide investors in mining stocks with a greater understanding of how fluctuations of commodity prices over time affect the prices of the mining stocks they hold, or intend to sell or buy. Three mineral commodities, gold, silver, and copper, were used as case studies, since market data on these commodities is readily available in the public domain. Nine market indices covering all three mineral commodities were selected. These are based on clearly defined criteria with the intention of eliminating ambiguity and to test for correlation with the three sets of mineral commodity prices. Nine mining companies, which were not the primary drivers of the relevant indices employed in the study, were used to validate the results obtained from the indices in order to avoid duplication of the same correlation during cross-checking. Each commodity price was adjusted for operating costs. For each market index, an average operating cost was calculated from the companies comprising its basket, while each company's annual operating costs were used for the stocks of the individual companies examined. The data was collected for the period January 2004 to October 2010. This period was further split up into three sub-periods to account for the Global Financial Crisis (GFC) period that started in mid-2008. We conclude that mining stock prices are correlated with mineral commodity prices, but with spot and forward prices exhibiting stronger correlations than long-term price. This finding should be useful for evaluation purposes. Where cash flow methodologies such as discounted cash flow or earnings per share are used to value ordinary shares and commodity prices are required to estimate future cash flows, the findings suggest that spot prices should be used as opposed to long-term prices. The work reported in this paper is part of a current MSc research study at the University of the Witwatersrand.
A perspective on the supply and utilization of mining graduates in the South African context.
(The Southern African Institute of Mining and Metallurgy., 2013-03) Musingwini, C.; Cruise, J.A.; Phillips, H.R.
The South African mining industry continues to be a major source of employment at a time when at least 25 per cent of the working age population is unemployed. At the same time the industry faces a skills shortage in many of the disciplines necessary for its future health. The University of the Witwatersrand, University of Pretoria, University of Johannesburg, and University of South Africa have historically produced mining graduates for the South African mining industry with any shortfall being met by the recruitment of overseas graduates. More recently, the global shortage of engineers and other mining industry professionals has seen a reversal of this trend and a very significant emigration of well-educated and highly skilled personnel. The traditional career path for mining graduates is in production and mine management. However, there is the parallel (and possibly more pressing) need for specialized skills in such fields as ventilation, rock engineering, mine planning, mineral resource evaluation, and mineral asset valuation. Chronic shortages in these essential areas continue to hamper the development of the industry and may well frustrate its ambitions to be safe, healthy, and profitable into the future. The permeability of skills across sectorial boundaries within the mining industry requires that skills shortages in the platinum sector are not looked at in isolation, but within the context of the entire industry. This paper reviews the efforts being made by the universities, at both undergraduate and postgraduate levels, to meet the needs of the South African mining industry in terms of the required numbers and the range of specialized skills.
Mine Planning and Equipment Selection (MPES 2015).
(The Southern African Institute of Mining and Metallurgy., 2016-03) Musingwini, C.
Extract from Comment: The Southern African Institute of Mining and Metallurgy (SAIMM) hosted the 23rd International Symposium on Mine Planning and Equipment Selection (MPES 2015) at the Sandton Convention Centre in Johannesburg from 9 to 11 November 2015. This was the first time that South Africa has hosted the MPES in its 25-year history. This conference’s theme was ‘Smart Innovation in Mining’ in order to recognize technological innovations and new ideas that are required to prepare the industry for the mine of the future.
Presidential address: Optimization in underground mine planning-developments and opportunities.
(The Southern African Institute of Mining and Metallurgy., 2016-09) Musingwini, C.
The application of mining-specific and generic optimization techniques in the mining industry is deeply rooted in the discipline of operations research (OR). OR has its origins in the British Royal Air Force and Army around the early 1930s. Its development continued during and after World War II. The application of OR techniques to optimization in the mining industry started to emerge in the early 1960s. Since then, optimization techniques have been applied to solve widely different mine planning problems. Mine planning plays an important role in the mine value chain as operations are measured against planned targets in order to evaluate operational performance. An optimized mine plan is expected to be sufficiently robust to ensure that actual outcomes are close or equal to planned targets, provided that variances due to poor performance are minimal. Despite the proliferation of optimization techniques in mine planning, optimization in underground mine planning is less extensively developed and applied than in open pit mine planning. This is due to the fact that optimization in underground mine planning is far more complex than open pit optimization. Optimization in underground mine planning has been executed in four broad areas, namely: development layouts, stope envelopes, production scheduling, and equipment selection and utilization. This paper highlights commonly applied optimization techniques, explores developments and opportunities, and makes a case for integrated three-dimensional (3D) stochastic optimization, in underground mine planning.
Relevance or extinction?
(The Southern African Institute of Mining and Metallurgy., 2016-10) Musingwini, C.
Extract from Editorial: We are well-known for being one of the oldest professional associations in the local minerals industry, hosting the highest number of excellent conferences annually, publishing an internationally accredited technical journal every month, and having functional branches locally and in neighbouring countries. Our Office Bearers and committee Chairpersons meet once a year to review our strategy.
Mine of the future - A mining CEO's perspective.
(The Southern African Institute of Mining and Metallurgy., 2017-05) Musingwini, C.
Extract from Editorial: The mining CEO of the future will be a strategist capable of navigating complex integrated stakeholder management, forging sustainable win-win partnerships, and enforcing regulatory adherence and good governance. Such a CEO is likely to succeed as he or she can enlist the support of shareholders, governments, employees, and communities that are increasingly, and rightfully, demanding to share in the benefits of the resources mined in their jurisdictions.
Development of a computer-aided application using Lane's algorithm to optimize cut-off grade.
(The Southern African Institute of Mining and Metallurgy., 2016-11) Githiria, J.; Musingwini, C.; Muriuki, J.
The maximization of net present value (NPV) is a primary objective in open pit mine planning processes. In an attempt to meet this objective, cut-off grades are considered in all the stages of mining. There are three stages involved in resource extraction, namely mining, processing, and refining/marketing, which are all defined in Lane's approach. Using Lane's approach, the economics involved in each stage are identified independently and interact to provide an optimum cut-off grade. A hypothetical block model is used to illustrate how a computer application (Cut-off Grade Optimiser) that was developed in this study is used in the optimization of cut-off grades using Lane's algorithm. This paper analyses the application of Lane's approach for a single element in cut-off grade optimization as applied in the calculation of the optimum cut-off grade through a computer-Aided application. Although Lane's approach is not complex it is not widely applied to maximize the NPV of mining operations as the iterative calculations can be lengthy. The computer application developed in this study shows how Lane's algorithm combined with a linear programming function can optimize cut-off grade with regard to the complex situations faced by mining operations. The application saves users from performing otherwise lengthy, iterative calculations.

Research Outputs (Mining Engineering)

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