Browsing by Author "Fey, Martin"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Open Access
    Apophyllite weathering and the aqueous geochemistry of a Karoo breccia pipe
    (2002) Cavé, Lisa Caryn; Fey, Martin; Jackson, Graham; Nordström, Kirk
    Apophyllite is a phyllosilicate mineral commonly associated with hydrothermal environments. It is a major secondary phase occupying fractures in a dolerite breccia pipe on the farm Kopoasfontein, outside Calvinia in the western Karoo, South Africa. Groundwater abstracted from this breccia is uncharacteristically alkaline (pH 10) and high in fluoride (11 mg/L) for a natural water and the link between the groundwater chemistry and breccia pipe minerals has been investigated.
  • Thumbnail Image
    Item
    Open Access
    Effects of waste disposal on soil and water chemistry at an industrial complex near Somerset West, South Africa
    (1997) Doel, Sean Laurens; Willis, James; Fey, Martin
    The estimated total annual production of waste in South Africa is 318 million metric tons. Of this waste, 3.8%, approximately 12 million metric tons, arises from the chemical manufacturing industry. Although increasing attention is being given to methods of land treatment for waste disposal waste is still disposed of by dumping/stockpiling. This study focuses on the effects of such waste disposal on soil and water chemistry at an industrial complex near Somerset West, South Africa. Since 1903 a multitude of industrial activities have occurred on the site including manufacture of explosives, chemicals, fertilizers and vinyl coated products: Decommissioning of the industrial complex is presently in progress. The overall objective of this study was to conduct an investigation of the water and soils in an area termed the Dead Tree Area. The area was considered of particular interest due to the presence of a sulphur stockpile, gypsum waste dumps and fertilizer wastewater evaporation site located immediately adjacent to the area. Four key objectives were addressed in the study, namely: (i) to chemically characterise the water and soils in the Dead Tree Area, (ii) to assess the degree of contamination of the water and soils in the area, (iii) to question whether tree mortality in the area could have resulted from toxicy or deficiency effects, and (iv) to determine the potential of gypsum application as a means of remediating dispersed, sodic soils.
  • Thumbnail Image
    Item
    Open Access
    The mobility of metals in acid mine drainage from abandoned coal mines
    (1997) Halbich, Torsten Franz Joachim; Willis, James; Fey, Martin
    The acid mine-drainage contaminated Blesbokspruit catchment west of Witbank in Mpumalanga province, South Africa has been investigated, by analysis of its waters, sediments, precipitates and algae, to obtain an understanding of the processes which control the mobility of metals in these waters. The Blesbokspruit drains acid mine drainage originating in surrounding, abandoned coal mine workings. The upper Blesbokspruit (approximately 8 km) including the stream origin, AMD outwelling points, downstream AMD retention ponds and a small wetland were selected for this study. Water, sediment, precipitate, and algae samples were collected from the Blesbokspruit. The water quality of the catchment was determined and compared to mineralogical and major and trace element analyses of sediments, precipitates, and algae. The pH and total dissolved solids of the catchment waters ranged from pH 2.6 to 7.4 and 147 to 3071 mg/ t, respectively. Associated precipitates consisted primarily of jarosite with minor amounts of goethite, lepidocrocite, ferrihydrite and gypsum, with ferrihydrite being the major component of only one precipitate sample. The presence of algae at one of the sampling sites appeared to act as a template for the precipitation of ferrihydrite in a low pH and high acidity environment. Speciation modelling of the Blesbokspruit waters indicated waters saturated with respect to jarosite, goethite, and quartz, in equilibrium with jurbanite, alunite and gypsum, and undersaturated with respect to ferrihydrite and kaolinite. The mobility of iron in the sulphate rich Blesbokspruit waters appeared to be controlled by pyrite oxidation and the solubility of the basic iron sulphate mineral jarosite. In contrast Al mobility appeared to be influenced by different mechanisms. Acidity of the Blesbokspruit waters correlated well (r = 0.942) with Al concentrations in the waters. Dissolved Al correlated with dissolved silica (r = 0.757) in the Blesbokspruit waters and exchangeable acidity correlated with exchangeable Al (r = 0.761) in the associated sediments. The data suggested that Al behaved conservatively in the pH < 4 Blesbokspruit waters and that Al solubility is controlled by dissolution of clay minerals and adsorption to organic matter in the sediments. Although precipitates contain trace elements, precipitation does not have a major effect on the concentration of trace elements in the associated low pH waters. Trace elements were, however, accumulated in the sediments of the Blesbokspruit streambed and the wetland. The wetland acts as a sink for dissolved Na, Ca, Mg, Fe, Mn, Zn, Ni, Pb U, Cu and Co. The mobility of these elements appeared to be controlled by the dissolution of minerals containing these elements and adsorption to organic matter in the wetland and streambed sediments. Not all metals were, however, completely immobilised, and toxic concentrations of Pb (1.3 mg/ t) and elevated concentrations of Al (40 mg/ t ), Fe (1.6 mg/t) and Mn (6.5 mg/t) remained in the water downstream of the wetland.