It is estiamted that a massive 300 million litres of water laced with sulphuric acid and heavy metals bubble to the surface around Johannessburg, this is known as acid mine drainage (AMG).
AMD is a side affect of South Africa's long mining history, it occurs when the rain or ground water mixes with the chemical sludge in the bottom of the mine shaft that contains anything from sulphuric acid to carcinogenic heavy metals which in turn can and has entered drinking water.

The problem isn't evident when you asses each mine individually but when you incorporate mines in a district and asses that as a whole. In the past environmental impact assessments (EIAs) were done taking one mine into acount at a time, this neglected the effects multiple mines had on a heavily mined area. A new scheme has been devised to attempt to manage entire regions and control ADM at its source.

There is still the unsolved problem of all the disused mine's where AMD had filtered into the water table. It has been suggested using reed-dominated wetlands, either natural or artificial, to filter the water.

A report by South Africa's National Nuclear Regulator in 2007 identified a minimum of 100 communities located on radioactive soil due to AMD in mining area's.

It takes an average of 5-10 years for disused mine's to fill up with water and overflow causing a serious risk to land, drinking water and peoples health. It has been put to the government that major water catchment and agricultural area's should be designated a mine free zone.

In Mpumalanga, the small farming and industrial town of Middleburg, land has been left unusable due to AMD. Not only that but the drinking water has also become a victim of AMD and now carries twice the World Health Organization's limit on sulphates. Yet still, there are 5000 applications currently waiting approval for mines in the Mpumalanga area and many of these are on land already identified for the rural poor.