Source: TimesLive

If left unchecked, the millions of litres of rapidly-rising acid mine water under Johannesburg will start flooding the lower levels of the Gold Reef City tourist mine early next year.

Shortly thereafter, the acid mine drainage, as it is known, will pass through an "environmentally critical" level - with potentially devastating consequences - before starting to flow out on the surface.

This is according to a report titled "Mine Water Management in the Witwatersrand Gold Fields with Special Emphasis on Acid Mine Drainage", compiled by a group of experts and presented to Cabinet last week.

A copy of the document, dated December, was posted on the department of water affairs' website on Thursday.

It warns that if the water is allowed to continue to rise, it will start "decanting in low-lying areas in the vicinity of the ERPM Mine in Boksburg and possibly elsewhere across the Witwatersrand".

Before this, it will "flood the underground mine operated as a tourist attraction at Gold Reef City".

According to a chart contained in the report, this will start happening in March next year.

The water will also "rise to an environmentally critical level where local groundwater systems could be influenced, particularly the dolomitic aquifers to the south, ERPM in Boksburg and Durban deep in Roodepoort".

Among the threats posed by the rising acid water -- which has a pH of three, approximately that of lemon juice -- is increased seismic activity, including earth tremors.

"This could have a moderate localised effect on property and infrastructure," the report finds.

It recommends urgent action.

Recommendations

"It is recommended that AMD [acid mine drainage] intervention and management measures are undertaken in the Western, Central and Eastern Basins as a matter of urgency."

The basins referred to are areas of interconnected mining tunnels underlying the Witwatersrand. Johannesburg is located atop the so-called Central Basin.

The acid water in the Western Basin, below the Krugersdorp-Randfontein area, started decanting in 2002.

According to the report, the current treatment of the overflowing acid water is inadequate, and poses a threat to the Cradle of Humankind World Heritage Site.

Minister in the Presidency Trevor Manuel on Tuesday moved to reassure Gauteng residents there was "no cause for panic" about the acid mine water.

Briefing journalists at Parliament following last week's Cabinet meeting, he said the executive had examined recommendations by the team of experts on how to deal with the threat of AMD.

"As a government, we want to give all South Africans the assurance that this matter is receiving attention; that the science is exceptionally good on this matter; and that there is actually no cause for panic about it. I want to repeat that: there is no cause for panic about it," Manuel said.

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