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Papers by Trust Tendai Masiya

The current discourse on small-scale mining in Zimbabwe has predominantly been a characterization... more The current discourse on small-scale mining in Zimbabwe has predominantly been a characterization of the current state of the sector. This paper focuses on the evolution of the sector through three historical epochs, namely the pre-colonial period (before 1890), colonial period (1890 to 1979) and the postcolonial period (after 1980). The development of the sector is looked at in terms of economic significance, mining methods, processing techniques, government support and legislation. The sector has remained of great economic importance since the pre-colonial times, especially in terms of its contribution to national output, employment, and poverty alleviation. From the efforts of pre-colonial small-scale miners several of the larger mines have developed. However, its contribution to regional development has been limited. The paper generally concludes that today’s small-scale miners, albeit with minor technological improvements, are still using the same methods that were employed by ...

Mining injuries in Zimbabwe constitute a large percentage of all injuries in the country, and are... more Mining injuries in Zimbabwe constitute a large percentage of all injuries in the country, and are among the highest in the region. This paper summarizes and explains the injury patterns over the period 2000-2002. Using a sample of 15 gold mines and data for 2000 as a case study, a log-transformed econometric model is used to investigate effects of injuries on production. The whole study period represents near normal conditions in the industry, before economic recession started to fully affect it. Such a retrospective study facilitates formulation of reflationary strategies and post-recession comparison. The five major causes of injury were striking by object, trucks and tramming, moving or rolling broken rock, machinery operation and fall of ground; and cases were higher for underground operations. Injuries decreased over the year from January to December. Over the week, the highest number of cases occurred on Tuesdays, while in a given day cases generally increased up to 1 pm and t...

Journal of Water Resource and Protection, 2015

This study investigates the concentration of metals namely aluminium, manganese and cobalt in two... more This study investigates the concentration of metals namely aluminium, manganese and cobalt in two matrices: sediment and fish organs (whole muscle stomach tissue, gills, liver and kidney) in an urban river, Mukuvisi River, Zimbabwe. River bed sediments and fish samples were collected simultaneously at five sites over seven months (September 2008-April 2009). Concentrations of aluminium, manganese and cobalt in the selected fish organs and sediment were estimated using the Flame Atomic Absorption Spectrometry (FAAS). Water limnochemical aspects, dissolved oxygen, pH, temperature and conductivity were measured concomitantly at each site. Aluminium had significantly higher mean concentrations and bioconcentration factors in both sediments and fish tissues relative to cobalt and manganese. Cobalt and aluminium were detected in all fish tissues, whilst manganese was not detected in muscle and liver. Significant differences in bioconcentration factors for the metals in organs of the same fish species analysed in this study show differences in metal assimilation. Metal specific river rehabilitation methods need to be applied for the future restoration of the ecological integrity of Mukuvisi River.

Froth flotation is widely used for concentration of base metal sulphide minerals in complex ores.... more Froth flotation is widely used for concentration of base metal sulphide minerals in complex ores. One of the major challenges faced by flotation of these ores is the ever varying grade and mineralogy. This therefore calls for a continual characterisation and optimisation of flotation parameters such that concentrator performance as a whole is always maintained. In this study, the robust Taguchi experimental design method was used to determine the optimum conditions for the flotation of nickel, copper and cobalt from a nickel-copper sulphide ore. The parameters investigated include collector dosage, percentage solids, depressant dosage and pH. The effects of these parameters at three different levels on the recovery of Ni, Cu and Co were investigated using an L 9 Taguchi orthogonal array. The optimum conditions for the recovery of the base metals are collector dosage, 80g/t; pH, 10.15; %solids, 25; and depressant dosage, 100g/t. Relative significance of flotation parameters (based on difference between max and min. values) indicates that pH has the most significant effect on the recovery of nickel, copper and cobalt during flotation. Analysis of variance showed that pH and depressant dosage were the most significant parameters affecting the recovery of Ni, while collector dosage and percentage solids were insignificant. None of the tested parameters significantly affected copper recovery whilst pH was found to also significantly affect cobalt recovery.

Journal of Water Resource and Protection, 2015