Yolande Nel
The great Limpopo is under attack from a deadly devil proven to be a fast growing concern to environmentalists who have identified a ticking time bomb largely ignored by the national government.
Listed with the great waters of the world – the Amazon, the Mississippi, the Nile and the Zambezi – the Limpopo is the second largest river on the African continent that rises to flow eastwards to the Indian Ocean. Communities situated along its course are dependant on this life-giving natural resource for purposes of sustainable existence.
The threat, however, is posed by Acid Mine Drainage (AMD), the uncontrolled discharge of contaminated toxic water from abandoned mines in the Witwatersrand area, which has been subjected to mining operations for more than a century, as stated in a concise overview by Federation For A Sustainable Environment Chief Executive Officer Mariette Liefferink. According to further documentation AMD follows the same path as water and is likely to persist for centuries.
Predicted by specialists as early as 1996, the magnitude of the first decanting of water from flooded gold mines at Krugersdorp and Randfontein – collectively referred to as the Western Basin Mine Void – seemingly caught the country off-guard in 2002. During August of that year the decanting water from a defunct mine shaft entered the dolomitic aquifers underlying the Cradle of Humankind World Heritage Site.
It was learnt that it is now also finding its way to Limpopo through initial infection of the Crocodile River. As stated in a fact sheet on the web, the Crocodile River is the largest of the Limpopo tributaries in terms of catchment area and volume of flow. The Hartbeespoort Dam commands a large portion of the total catchment runoff for the Crocodile, it was further stated.
Liefferink explained that Rand Uranium (previously Harmony Gold), Mintails and DRD Gold have been engaged in mining operations in the Randfontein area. She referred to a directive of the Department of Water Affairs dating back to 2002, which attributes 46% liability to Rand Uranium, another 44% to DRD and 0,8 % to Mintails. The remaining 9,2% liability is claimed by the department itself. The parties were compelled to treat the water in order to bring it to a drinkable quality level. However, two of the mines have seized to recover the water some two months ago.
Liefferink further quoted from a hydro-geological assessment of AMD impacts in the West Rand Basin done by the Council for Scientific and Industrial Research: "The subregion straddles the subcontinental surface water divide between the Vaal River basin to the south and the Limpopo River basin to the north. These circumstances implicate the Upper Vaal and the Crocodile (West) and Marico Water Management Areas, respectively, in regard to catchment management agencies."
Another explanatory quote from a report on the impact of the discharge of treated mine water on the receiving water body of the Crocodile River system states: "Water flowing south forms part of the Mooi River/Vaal River Catchment and water flowing north forms part of the Crocodile River/Limpopo River Catchment."
All along the government has been loathe in addressing a situation with a hugely detrimental effect on the environment, stressed Liefferink. It is a matter of national concern that thus far formed the contents of submissions to, among others, Parliament and lately to the Human Rights Commission. Over time the problem has multiplied, with pollution rapidly spreading through water ways. In the meantime environmentalists attempt to raise adequate awareness resulting in intervention, it was learnt.
Asked for comment, local water expert Johan Pieterse indicated that AMD is characterised by low pH (high acidity), high salinity levels, elevated concentrations of sulphate, iron, aluminium and manganese, raised levels of toxic heavy metals - such as cadmium, cobalt, copper, molybdenum and zinc and possibly even radionuclides. "AMD is not only associated with surface and groundwater pollution, but is also responsible for the degradation of soil quality, aquatic habitats and for allowing heavy metals to seep into the environment An exacerbating characteristic of AMD is its long term persistence – it is extremely difficult to rectify.
He referred to certain expert assessments by the Environmental Protection Agency in 1987 concluding that ‘problems related to mining waste may be rated as second only to global warming and stratospheric ozone depletion in terms of ecological risk. The release to the environment of mining waste can result in profound, generally irreversible destruction of ecosystems’.
A high confidence study of the fate and pathway of heavy metals and radionuclide associated with mine decant and AMD from local and distant mining activities relevant to Limpopo should be undertaken, he suggested. "This study will reveal where the pollution is traveling and if there is human risk involved, and therefore where management intervention is required."