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Acid Mine Drainage

Inadequate treatment of acid water flowing into the Tweelopiespruit

 

The Tweelopiespruit is a stream that flows through the Krugersdorp Game Reserve on the West Rand, near Johannesburg, South Africa

 The treatment process being undertaken by the mining company Rand Uranium, with the support of the Department of Water Affairs, since April 2010 is not working. The water flowing out of the reserve is still acidic and contains very high levels of sulphates and heavy metals, including radioactive uranium. This water contaminates the water supplies of thousands of people downstream.

 

 Click here to see photos of the Tweelopiespruit and pH test results taken on 8 May 2010: http://www.earthlife.org.za/?p=1035

In January 2010 the amount of acid mine water flowing into the Tweelopiespruit increased dramatically, because millions of litres of water began to pour out of an old mine shaft near the headwaters of the stream. (See photo below)

 The volumes of toxic flowing out of the shaft were about four times more than the capacity of the mining company to deal with them.

 In desperation, and after  concerns being raised by civil society groups, the government gave R6.9 million towards the treatment effort. This money paid for vast quantities of lime for the partial treatment of the water. (See photo below)

 The partial treatment involves adding lime which makes the heavy metals fall out of solution. The iron in the water makes it an orange-red colour.

 The partially treated water should be contained in a lined settling pond. The heavy metals fall out of the water into the mud at the bottom of the pond. The sludge is then taken to a tailings dam. But this does not happen to the waters of the Tweelopiespruit.

 The Tweelopiespruit and its dams in the Krugersdorp Game Reserve, primarily Hippo Dam, are being used as settling ponds. The heavy metals, including radioactive uranium, accumulate in the mud at the bottom of the stream and dams. Under certain environmental conditions, these metals can become mobilised.

 There seems to be no systematic system for monitoring the water flow and the amount of lime needed to neutralise the acid mine water. Often too little lime is added. This means that iron is still dissolved in the water. A chemical reaction  between the iron and the water makes the water acidic. If the mud gets stirred up, for example by animals, the heavy metals can get dissolved into the water again and transported downstream. 

 

Decant of acid mine water, near a wetland that drains into the Tweelopiespruit, Black Reef Incline, 30 January 2010

Decant of acid mine water, near a wetland that drains into the Tweelopiespruit, Black Reef Incline, 30 January 2010

The above photo shows acid mine water flowing uncontrollably onto the surface from an old mine shaft. The water contains high concentrations of heavy metals dissolved in the acid water. These include iron, cadmium, arsenic, lead and uranium – which is radioactive. The picture below was taken about 200m down hill from this shaft. 

 

Acid mine water flowing into the wetland that drains into the Tweelopiespruit, 30 January 2010

Acid mine water flowing into the wetland that drains into the Tweelopiespruit, 30 January 2010

 

 

 

Rand Uranium pond downslope from the decant mine shaft, with partially treated acid mine water, 30 January 2010

Rand Uranium pond downslope from the decant mine shaft, with partially treated acid mine water, 30 January 2010

 

Lime being added to the acid mine water. Across the R24 from the Krugersdorp Game Reserve. 8 May 2010. (Photo: Alistair Clacherty)

Lime being added to the acid mine water. Across the R24 from the Krugersdorp Game Reserve. 8 May 2010. (Photo: Alistair Clacherty)

 

Discharge into Tweelopiespruit, just outside the Krugersdorp Nature Reserve, 8 May 2010 (Photo: Alistair Clacherty)

Discharge into Tweelopiespruit, just outside the Krugersdorp Nature Reserve, 8 May 2010 (Photo: Alistair Clacherty)

 

A reactor pit on the West Rand. Meant to contain partially treated acid mine water. But this pit is full. So the Tweelopiespruit is being used as a settlement pond instead.

A reactor pit on the West Rand. Meant to contain partially treated acid mine water. But this pit is full. So the Tweelopiespruit is being used as a settlement pond instead.

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