Browsing by Subject "coal mining"

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    A cleaner production assessment of the ultra-fine coal waste generated in South Africa
    (2007) Reddick, J F; Von Blottnitz, H; Kothuis, B
    The South African coal mining industry is currently disposing of about 10 million tons of ultra-fine coal (<150 µm) per year. Once discarded, these sulphur-containing ultra-fines contribute to several environmental problems. As part of a project initiated by the Water Research Commission to investigate the use of Cleaner Production (CP) in the mining industry, a study was carried out to determine whether a CP approach could be used to identify opportunities to reduce this coal waste, and to determine which of these opportunities would be most feasible. In order to do this, a CP assessment was conducted at three case study collieries in the South African Witbank coalfield. Mass-balancing and sampling, followed by laboratory characterisation tests and site surveys, were used to determine the quantity, quality and sources of the ultra-fine coal at the three collieries. Literature reviews, brainstorming sessions and interviews then followed to generate the CP options. An environmental, economic and technical feasibility assessment was then prepared for each option, to determine the most viable interventions for implementation. A number of opportunities were identified through the assessment. By preventing coarser coal from being discarded with the ultra-fine coal, the quantity of coal disposed of could be decreased at all three collieries, and by up to 24% in one case. Increasing the crusher top size would reduce the amount of coal that is milled to less than 150 µm, so that less is wasted. The ultra-fines that have already been disposed of on slurry dams can be completely reclaimed and converted into a valuable product, which can be sold as power station feedstock. The newly processed ultra-fines could be beneficiated using flotation and exported together with the coarser coal. The results of the assessments thus suggested that workable CP opportunities to reduce ultra-fine coal wastage exist at the sites investigated, and that their feasibility is colliery-specific. The associated financial benefits of the proposed options suggested that CP is a realistic approach to addressing environmental problems.
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    Open Access
    Winter bird assemblages, species richness and relative abundance at a re-vegetated coal mine in the Middelburg district, Mpumalanga Province, South Africa
    (2005) Little, I T; Little, R M; Jansen, R; Crowe, T M
    Winter bird assemblages, species richness and relative abundance were investigated at six re-vegetated sites within the Middelburg Coal Mine (Mpumalanga, South Africa) and compared with those for a site thought to be representative of un-mined biotope within the nearby Witbank Nature Reserve. Age of site since initiation of re-vegetation had little or no apparent effect on richness or abundance. Adjacency to currently active mining and variation in current land management practices appeared to have much more profound effects. Sites surrounded by active mining had lower richness and abundance. Those with 40% or more land left as fallow and strips of un-mowed grass as well as artificial ponds had higher bird richness and abundance.