Small victory in blighted mining landscape

Mariette Liefferink’s red high-heeled sandals sink into the watery earth. She totters to a mining pit overflowing with copper water that is stained like blood. That this is filled with partially treated acid mine drainage (AMD) is a small victory for the environmental activist.

For several years, the grandmother of two has led concerned activists, scientists, politicians and communities on her toxic tours of the West Rand’s blighted mining landscape. But then, the untreated water was a toxic flood largely ignored by authorities – now it has been reduced to a trickle. It shows her work is paying off.

“The mere acknowledgement by the government of the AMD crisis and the emergency implementation is a victory”, she says. “The spontaneous decant of AMD has stopped. There are more volumes being treated on a sustainable basis. It’s not a complete measure, but at least action has been taken by the government.”

Since 2002, millions of litres of untreated AMD have been decanting from disused mine shafts at this site in Randfontein into receiving waterways every day.
But this has largely been curtailed because of the upgrade of a neutralisation plant now treating more than 30 million litres of AMD a day by neutralising the toxic water with lime to rid it of the heavy metals and acidity that contaminate it. Still, high levels of sulphates remain, rendering the water unfit for human consumption. It’s how the process has been followed that’s a problem for Liefferink, who heads the Federation for a Sustainable Environment.
It is appealing a decision by the Department of Environmental affairs earlier this month that exempted the Department of Water Affairs from conducting an environmental impact assessment (EIA) for the immediate and short term interventions for its Witwatersrand AMD mitigation project, pegged at more than R2 billion.

“There’s not been sufficient reasons supplied by the minister of water affairs on why she authorised the exemption. We want to know, what is the risk assessment regarding end water users, the ecology and the impact on the tourism sector.

“The agricultural sector has to carry the costs. There has been no apportionment of liability with the mining houses done”, says Liefferink.

Too many uncertainties remain. “We want surety that the water that flows after neutralisation from here into the Tweelopiespruit is fit for use, but the Department of Water Affairs has not given us water quality data for a year.

About 500 tons of salt will be released very day into the Vaal River system when pumping and treatment of the AMD that is rising in the Central Basin – which runs beneath Joburg – gets under way. This will reduce the capacity of the Vaal to dilute the high salinity

Sulphate levels about 650mg/l may result in non-adaptive diarrhoea in humans and sulphate levels over 250mg/l will lead to the suppression of copper and selenium in cattle, which causes low fertility and poor condition. The World Health Organisation says water with a sulphate concentration of 200mg/l is safe to drink, but the Department of Water Affairs believes 600mg/l is fit for human consumption.

“The problem is that while neutralisation removes some of the metals, the metals that remain are often not within regulatory limit. The high sulphates are of huge concern. There’s been no quantification of the health risks.”
Graham Trusler of Digby Wells, the environmental consultants who were supposed to conduct the EIA for the immediate and short term interventions has found that were the department to authorise the EIA, it would “have possibly found that the short term would have significant impacts on downstream water users due to the high salinity.”

In the Central Mining Basin, where AMD is steadily rising beneath Joburg’s city centre, the environmental critical level is expected to be breached by September. It will follow the Eastern Basin a year later. This means authorities only have months, says Liefferink, to start the process of erecting neutralisation plants to pump and treat AMD elsewhere.

In its appeal, the Federation for a Sustainable Environment will argue that the likelihood of people coming into contact with radioactively polluted sites “has so far been completely ignored” by authorities, while other risks include increased seismicity and the “possible subsidence of tailings structures incorporated into infrastructure such as the M2 highway.”

As the Central Basin floods, residents could also be exposed to the radioactive gas radon through open shafts.

The feasibility study for the long term treatment of AMD will be released next month. Liefferink hopes this will be linked to the short term AMD project, and see desalination of AMD get off the ground.

“There are many alternative technologies that must be assessed and the department is under-capacitated.”

Back on the West Rand, raw AMD still taints the barren landscape. “The problem is it’s still in the soil and there are no plans to rehabilitate it at all in the short and long term”, adds Liefferink. “These degraded areas are secondary sources of AMD.”


Sulphates rocket in aquifer

When Garfield Krige tested his groundwater in 2002 to ensure it was safe to drink, the concentration of sulphates was well within regulatory limits. A decade later, it has exploded.
For this “almost exponential” increase in the pollution of the Zwartkrans aquifer, the hydrologist blames the decant of acid mine drainage (AMD) – the toxic and radioactive water that was allowed to seep from old mineshafts in the Western Basin, poisoning the Krugersdorp Game Reserve and pouring into waterways flowing to the Cradle of Humankind.
Krige, who lives on a plot in the Cradle, reveals how his water tests in 2002 showed sulphate levels of 172mg/l. Last year, the concentration had risen to 442mg/l “proof that a sudden and exponential increase in the sulphate concentration is occurring within this aquifer.”
And even as authorities have essentially stopped the decant on the Western basin, the sulphate levels have remained high because the acidic water is only partially treated, leaving a high level of sulphates in the water.
“The rise in sulphates means that the water will not be suitable for human for human consumption by the end of the year”, he warns. “This aquifer is presently the sole drinking water source form ost of the residents in this area and also in areas beyond the local are where the samples are collected.”
The Department of Water Affairs said “the matter is presently under scrutiny of our geo-hydrologists.”

What quantity of sulphates are entering our river systems from neutralised acid mine drainage (AMD)?

  • The government’s immediate and short term solution to AMD is through neutralisation, where the water is treated with lime to reduce its acidity and remove toxic heavy metals. The process, however, does not remove sulphates. AMD typically contains 4 500mg/l of sulphates – the neutralised water contains 2 500 mg/l sulphates
  • On the Western Basin, 70 tons of salt are being released every day into the Tweelopespruit, which is part of the Crocodile West/Marico Water Catchment Area, from the millions of litres of neutralised AMD entering the river system.


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