Arsenic dispersion associated with the Barbrook gold mine in the Mpumalanga Province of South Africa

Master Thesis


Permanent link to this Item
Journal Title
Link to Journal
Journal ISSN
Volume Title

University of Cape Town

Arseniferous sulphide-hosted gold deposits associated with the Barberton greenstone belt, located in the Mpumalanga province of South Africa, have been mined on various scales since late last century. The Barbrook mine is located close to the Swaziland border in an area of the Barberton mountainlands which forms part of the Kaap subcatchment of the Crocodile River. Scattered small communities depend on local streams and boreholes in the area for drinking and irrigation water. Hence, the prime motivation for this study was the potential risk to human health associated with enhanced As mobility as a result of the sulphide mineral weathering which accompanies gold mining and processing. Sampling of local waters, soils and sediments, as well as the ore and waste rock at Barbrook was undertaken during a week of fieldwork in August 1996. A range of chemical analyses were performed on the various samples, including As analysis by hydride generation-atomic absorption spectroscopy and inductively coupled plasma - mass spectrometry. The Barbrook ore bodies are structurally controlled and hosted by banded iron formation, carbonaceous shales and carbonate-bearing schists. Within these ore bodies, As is mainly associated with auriferous arsenopyrite (FeAsS), although minor amounts also occur within pyrite (FeS₂) and ullmannite (NiSbS). Of the streams which flow through the mining lease, those at most risk of As contamination are Barbrook Creek, Low's Creek and Crystal Stream. Low's Creek flows through the main mine area, adjacent to the level 1O mine adit entrance, and past the processing plant before converging with Barbrook Creek. The latter receives water from the Shiyalongubo Dam which is the main water source for the area. Immediately downstream of the level 10 mine adit entrance, the steep eastern bank of Low's Creek is lined for several hundred metres with waste rock containing low grade ore. Tailings material from the processing plant is pumped to two tailings dams located about 5 km to the northwest of the plant and close to Crystal Stream.

Bibliography: pages 123-137.