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By Hugo Melo

Stormwater Control On Mines

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South Africa’s National Water Act of 1998 has highlighted the need to conserve its valuable resource in this water-scarce country. It lays down strict regulations on the discharge of contaminated water into the environment.

For the mining sector, the Act has required more effective control of stormwater – one of the main catalysts of contaminated discharge from mining areas. As part of the drive for best practice in this area, SRK assists clients with solutions that optimise the collection and containment of stormwater, and allow maximum re-use of water in processing. A key aspect of an effective stormwater control strategy is to isolate dirty water sources, such as workshop areas where oil may become mixed with surface water. Monitoring is also vital, to quickly establish the point and extent of any spillage from containment areas.

The water law has forced mines to focus on floodlines on or near their properties. In the context of climate change, mines need to proactively anticipate more frequent flood occurrences, which may exceed previous record levels. Mines’ stormwater control strategies must address the safety of others – such as surrounding communities or downstream areas – if they are to remain compliant with the law. Flooding of tailings dams is a particular risk, and is strictly enforced by the Department of Water Affairs Dam Safety Office.

The drawing below gives a simple schematic layout of the requirements for the location and capacity of clean and dirty water systems. The basic principle of separating clean and dirty water is used in many countries and the criteria may vary from country to country (1:100 year is the norm in some countries). The regulation relevant to the drawing is presently under review in South Africa and the revised requirements will certainly require mines to implement additional stormwater controls.

It is not only external stakeholders that benefit from better stormwater control. Mines derive a direct and immediate value from the protection afforded to their own infrastructure by using better control mechanisms.