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Case studies - South Africa

5.7 Dust management at Vaal River

The dust management programme implemented at the Vaal River operations in South Africa in 2005 has been relatively effective. The problems experienced here and, in particular, the concerns of the local community, were reported in the Report to Society 2004.

Since that time the western extension tailings storage facility has continued to grow, increasing in height from 32 m to 41.5 m. Tailings deposition has also increased from 22 million t to 24,7 t. To accommodate the increased tailings material, the height of the dam has had to be increased. During the process of a routine pipe lift, which was necessary for cycloning operations to proceed smoothly, the stabilised surface on a portion of the eastern wall was disturbed. This has resulted in a temporary increase in dust levels, which are expected to continue until cycloning operations resume at the beginning of 2006.

Dust emissions from the dried-out sulphur dam, located on the northern side of the Potchefstroom/Orkney road, have also increased significantly. The dam is currently in the process of being reclaimed, which in the longer term, will lead to a reduction in dust emissions. In the meantime, a short-term strategy has been implemented for dust suppression, including:

  • installation of sprayers – the initial system proved to be unsuccessful and consequently a micro-jet system is being investigated which should provide a much finer droplet, improving the agglomeration of airborne particles;
  • installation of bulk chemical storage tanks for dust suppressant chemicals which will reduce the lag time when urgent applications are required; and
  • spraying of ligno-sulphonate – a synthetic, non-toxic, eco-friendly binding agent has been applied over the dam surface to bind dust particles. Approximately 90% of the surface has been covered and the rest is scheduled for completion in early January 2006.

The dust monitoring programme, which comprises 17 dust fall-out buckets, has continued during 2005 with the latest results indicating compliance with legislation.

Although complaints regarding high dust emissions were lodged with the North West Department of Minerals and Energy (DME) during October 2005, AngloGold Ashanti was not singled out by the complainants. Nevertheless, following a meeting with all stakeholders, the DME constituted a formal dust committee comprising local authority and mine representatives, which will meet regularly to discuss dust issues and remediation measures.

Report to Society 2005