Stream sediment geochemistry of the Olifants catchment, South Africa: Implication for acid mine drainage

The Olifants primary catchment area, which straddles the border between South Africa and Mozambique, has a total area of approximately 87000 Km(2). The South African portion makes up 60 % (60000km(2)) of the Olifants and in turn straddles the provinces of Mpumalanga and Limpopo. Although industrial and agricultural activities are also important, the contribution of pollution from the mining activities within the catchment is significant as the result intense mining activities of various mineral commodities such as coal, gold, base metals and other mineral commodities with in the catchment area and yet not fully quantified. A multidisciplinary project is underway to investigate the severity of the mining impacts on the water resources and the ecosystem of the Olifants catchment area. One of the techniques adopted at the screening level pollution assessment to identify hotspot sites with respect to mine pollution is stream sediment and water analysis. Based on SXRF data of 118 stream sediment samples, 19 potentially impacted areas have been identified for further detailed investigation. The approach adopted herein suggests XRF data of stream sediment samples can be used as a preliminary screening tool for identifying potentially impacted areas for detailed investigation.