Geochemical studies of the Brugspruit Stream water and acid mine drainage (AMD) contaminant sources in the Brugspruit catchment area, eMalahleni (Witbank) Coalfield, Mpumalanga

Abstract: Acid Mine Drainage (AMD) is one of the world’s biggest environmental problems and arguably the most studied section of geo-environmental chemistry. It is mainly caused by oxidation of pyrite (FeS2). AMD is mainly associated with coal mining due to the FeS2 that may be found within the coal. The eMalahleni (formerly known as Witbank) Coalfield is no exception to this environmental problem. The eMalahleni Coalfield in particular, is to a large extent impacted by AMD due to the large sub- horizontal coal seams, open pits and voids as a result of coal mining. This study focuses on the Brugspruit stream which flows onto the eMalahleni Coalfield some 7 km west of the eMalahleni town. The Brugspruit is the main supplier of water to the nearby Hlalanikahle community. The study was conducted to contribute to the understanding of geochemistry of AMD water coming from the Transvaal and Delagoa Shaft (TDB), Douglas North (DN) and an underground seepage (SP) points, and their impacts thereof on the Brugspruit water chemistry. The TDB is an inclined shaft from the abandoned Transvaal and Delagoa Bay Colliery from which hot water (due to spontaneous underground coal combustion) decants throughout the year to three AMD remediation ponds before ultimately getting to the Brugspruit. Water samples were taken at 11 points in three different seasons, i.e. at the beginning of the rainy season, the peak of the rainy season and during the dry season. Taking repeated samples was done in order to understand the impact of the contaminant points at different seasonal stages. The Brugspruit was sampled at four points. The first sampling point was where it first enters the study area (before making contact with the TDB, SP and DN water) and was named BG. The second sample from the Brugspruit was taken at a point (BGDS) further downstream, where it had already made contact with the TDB and SP water. The third sample from the Brugspruit was taken from a point (BGB4DN, which is a wetland) before the DN water made contact with the Brugspruit. The fourth sampling point (BGLP) was further downstream after all the contaminant sources (TDB, SP and DN) had made contact with the Brugspruit. Four other points which are directly linked to (by receiving water directly from) the TDB were also sampled. These points were named...M.Sc. (Geology