Doctoral Degrees (Institute for Groundwater Studies (IGS))
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Browsing Doctoral Degrees (Institute for Groundwater Studies (IGS)) by Author "Deysel, Lore-Marie"
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Item Open Access Environmental geochemistry of the Waterberg coalfields(University of the Free State, 2015-07) Deysel, Lore-Marie; Vermeulen, P. D.English: The Waterberg Coalfields represent the last area in South Africa which contain large quantities of coal resources. The most important issue with economic growth and development is to take measures to minimise the impact on the environment. With the ever increasing demand for energy, the demand for continuous mining of coal increases and thus expands into areas not previously mined. The by-products of coal mining and the production of electricity from the coal leaves an environmental footprint. For this footprint to be minimised, all the risks associated with mining should be available and understood. Since there are still large coal deposits in the Waterberg which can be mined by opencast mining, the risk of the geological units still to be mined was assessed. Acid generation due the oxidation of mainly pyrite is a source of contamination that can impact the groundwater and to a lesser or no extend the surface water from the mining facilities. Another environmental risk is air pollution from mines, includingthat of Medupi Power Station which will commence shortly. It is a very dry area and thus the aquifers must be protected as far as possible. In this study area,coal is mined by the opencast method from the Karoo formation There currently only one active coal mine in the study area, namely the Grootegeluk mine which started operation in 1980. Samples were collected from exploration boreholes in all three areas in the region (partly weathered, Full succession and Middle Ecca). Acid-Base Accounting was done on all 800+ samples and it indicated that the interburden and discards contained the highest AMD potential while the overburden had the highest buffering capacity. The impact is clear on some of the monitoring boreholes on the site. Unlined facilities lead to the contamination of the aquifers to a point where the pH of the water is acidic. The monitoring boreholes close to the ash dump is affected by a raise in the total dissolved solids due to calcium and sulphate leaching from the ash. To get the total impact or toxicity potential of samples, it is necessary to identify the elements that are available in the different wastes that can leach into the environment. All the risks associated with the different geological units should be known so that the best decision and planning of waste facilities for future extensions can be made, and so that the negative footprint on the environment can be minimised.