INLSA

Threat: Visitors enjoy a ride at Gold Reef City. A professor has warned that polluted water is set to flood a popular historic mine shaft there. Picture: Sizwe Ndingane

Sheree Bega

A senior geologist is frustrated about the lack of urgency as rising levels of toxic acid mine drainage in Joburg’s Central Mining Basin place the future of Gold Reef City’s popular historic mine shaft in peril.

At the current rate, the toxic water will have flooded the shaft by June.

Professor Terence McCarthy, of the department of geology at Wits University, says that only around 20 months remain until acid mine drainage (AMD) starts to decant from the Central Basin, which runs beneath central Joburg and extends to Roodepoort and Germiston.

“If it wasn’t for the underground facility, I’d let the water rise higher in the Central Basin,” says McCarthy. “But I spend a lot of time there training students.

“In September, I spent three days underground. Thousands of people, especially kids, go through there. To me, it’s like the Castle in Cape Town.

“It’s part of our heritage – we can’t let it go. It’s shocking what is happening.”

McCarthy, who says that AMD is rising by around 10m a month, is concerned that time is running out.

“It has slowed down (in the Central Basin) and that has given us more time but we’re already in trouble… I’m worried that water is coming up at a fast rate and I feel there’s a need for urgency.

“We’ve got to get the pumps down at ERPM in a hurry. We’re running out of time.”

There is not enough time to build treatment plants and pumping stations, he says.

“To make a new pump station underground can take up to a year. We’ve got 20 months. If you get the timing wrong, because the water is coming up, you’ve had it.”

Gold Reef City says it has a professional team regularly monitoring the underground water levels to “keep track of all geological or environmental factors”.

“Mine management and a qualified mine engineer measure underground water levels every week. The current underground mine tours are operating normally and guests can be rest assured the tours are completely safe.”

McCarthy was among those who attended a public meeting this week, including environmental groups and mining representatives, held by Digby Wells Environmental.

It is conducting the environmental impact assessment for the Trans-Caledon Tunnel Authority (TCTA), which has been appointed to implement the government’s short-term solution to treat AMD. This involves neutralising the AMD to strip it of its acidity and heavy metals but high levels of salts will remain, that will contaminate the Vaal – and drinking water – and have to be diluted from expensive and fresh water sources.

The Department of Water Affairs predicts that if nothing is done to treat AMD, about 200 million litres of polluted water will seep from old mine shafts and flow uncontrolled into rivers and wetlands around Joburg and surrounding towns. About 2 000 tons a day of salts and 200 tons a day of metals will be released into rivers.

McCarthy says organisations such as the Federation for a Sustainable Environment (FSE), who oppose neutralisation of AMD in favour of desalination, could delay implementation of the short-term plan in the Central Basin.

“I’m worried that now with the public participation process, various groups might delay implementation. They are clouding the issue with things that can delay the implementation of pumping. I think we’ve got to remain focused – this is an urgent thing – to get the pumps working. We can’t obfuscate the issue with the whole thing of the quality of the water.”

AMD has been decanting from old mine shafts in the flooded Western Basin since 2002, polluting waterways, while on the Eastern Basin, pumping ground to a halt early last year, and the environment critical level is set to be breached in June next year.

Pumping of the Central Basin ceased in 2008.

“I’m saying let’s go back to 2008 and let’s go from there… It’s not like we’re doing anything worse than we experienced before. We can save the situation by bringing it in under control and avoiding the mess we’re in. We don’t need to see this AMD on the streets of Boksburg,” McCarthy adds.

He says the government’s longer-term solution, to make AMD fit for either industrial or human consumption, can improve water quality.

“The most important thing is to get the pumps going, and do the basic treatment like it was done in back in 2008.”

Koos Pretorius, of the FSE, says it wants portable desalination plants to be attached to neutralisation plants to treat the water to potable standards.

“All we’re asking for is a debate to have these figures on the table… The TCTA, in principle, is not going to entertain the idea of putting in portable desalination plants. But I’m asking that they look at it with an open mind, if it makes economic sense, we add it,” he says, adding that the benefits would extend to keeping the Vaal River system free of contamination.