SA's 6 000 abandoned gold and coal mines have sparked warnings by researchers and environmentalists of a water crisis. On the West Rand, the last active gold mine shut down in 1998. The pumping of water was halted, and the areas were allowed to flood. Four years later, contamination, or decant, began, taking both government and mining houses by surprise.
Buks se gat - Semi-treated
Two key water sources are affected. The Tweelopiespruit flows through the Krugersdorp Game Reserve to the Cradle of Humankind and eventually to Hartbeespoort Dam. And near Carletonville and Merafong, the Wonderfonteinspruit reaches Potchefstroom and joins the Mooi River before flowing into the Vaal River.
Both water sources have been affected by acid mine drainage, but it is the Wonderfonteinspruit that is threatening Gauteng's water supply, says CSIR researcher Phillip Hobbs.
Acid mine water sterilises its receiving environment. It is highly acidic and carries traces of sulphate, uranium, iron, aluminium and manganese. The volume of acid mine drainage surfacing in the gold fields near Krugersdorp alone is sufficient to fill at least 10 Olympic-size swimming pools every day, says Hobbs.
Acid mine drainage affects surface and groundwater, and destroys soil quality and aquatic life. It is difficult and costly to rectify.
Rand Water, which supplies water to 12m people in Gauteng and parts of four other provinces, draws water from the Vaal Dam which is upstream from most of the problems. Rand Water's Karl Lubout says if contamination were to occur, the company has the technology to treat it to international potable standards.
Soon after the decant began, Harmony Gold and Mogale Gold set up water-treatment plants near Krugersdorp.
Despite neutralising the acidity, the treated water still has a higher than normal metal concentration. It flows into the Tweelopiespruit just before the Krugersdorp Game Reserve through a hole in the ground called Buks se Gat. In the reserve, the water has filled a once dry dam. Though treated, it is still murky brown and turns plant life orange - a result of iron and manganese.
African Bush Adventures, which manages the reserve, wrote to the department of water affairs in September, detailing the death of aquatic life and buffalo, as well as aborted babies of two rhinos. It attributes these and other incidents to the quality of the water. The department has disputed this, saying the water quality, with the exception of sulphates, is within guidelines for livestock.
"There is a plan to set things right," says Jaco Schoeman, CEO of the Water Utility Company (WUC), set up by the mining companies to make the treatment of acid mine drainage profitable. The company intends building a treatment plant by 2010 to deal with polluted water from mines in Gauteng's western, eastern and central basins. The plant will remove metals from the water, making it potable.
The West Rand's Erin Brockovich, Mariette Liefferink, has welcomed the process, but says compensation for people affected by pollution needs urgent attention. Liefferink has become the voice of aggrieved farmers and informal communities whose livelihoods have been destroyed by the contamination.
Though WUC's solution addresses water pollution, tailings dams (mine dumps) pose a threat to local communities.
Rand Uranium, which is 40%-owned by Harmony Gold, will re mine existing dumps for gold, uranium and sulphates. Harmony environmental manager Rex Zorab says it is a commercial solution to rehabilitation of all dumps in the area.
But dust from tailings dams and waste facilities has respiratory and cancer risks, says Mogale City environmental manager Stephan du Toit. The footprint of the dust fallout is reportedly six times (5 681 ha) more than the total surface area of the tailings dams (978 ha).
Though there is no scientific evidence of health risks of the contamination, there are anecdotal accounts of an increasing number of children experiencing upper respiratory tract infections, deformities, kidney problems and lung cancer. The affected informal settlements are along the Wonderfonteinspruit, Reiger Park on the East Rand, and Riverlea, south of Johannesburg. Mogale City's Du Toit says: "This is a problem that affects everyone - those who make money and those who are affected by those who make money. We cannot be seen to be doing things in silence."
Financial Mail: Razina Munshi