Threat: The rising water level will affect mining underground and should the toxic acid mine water break to the surface the groundwater could be contaminated. Photo: Delwyn Verasamy
All three deep-level abstraction pumps at the government’s R1 billion Eastern basin acid mine drainage (AMD) treatment plant in Springs on Gauteng’s East Rand are no longer operational, leaving a tide of toxic mine water rising significantly underground.
Now, fears are growing over, among others, potential water contamination and of major job losses at affected local mines that may see their underground workings flooded.
Since spare parts were unavailable, repairs have stalled. Ekurhuleni mayor Tania Campbell said she is “deeply concerned” about the drinkable groundwater supply being contaminated, risking the health of residents. “Residents who utilise borehole water for hygienic purposes may experience skin problems if this water becomes contaminated.”
The loss of biodiversity caused by contamination “may have the potential to destroy existing ecosystems” in the city, she said. Polluted groundwater may also affect the agricultural sector if crop soils are contaminated, rendering harvests nonconsumable, while livestock could be poisoned by drinking the water.
Acid mine drainage is harmful to humans, plants and animals because it carries metals, atoms that emit radiation and salts in hazardous concentrations.
Risk of being compromised
Every day, the plant’s pumping station is meant to pump 70 to 100 million litres of the polluted water from the mining void that lies beneath the densely populated towns of Benoni, Brakpan, Springs and Nigel before it is neutralised and discharged into the Vaal river system.
This is to keep the AMD – a legacy of more than 120 years of gold mining – from breaching the environmental critical level (ECL) to protect dolomites (AMD dissolves dolomites) and groundwater resources. The level, too, needs to be maintained to prevent the decant of the acidic mine water. This is when the flooded system “daylights” and flows into the environment, causing environmental degradation.
“With the current problems regarding the scaling of the pumps and the cessation of pumping within the Eastern basin, the ECL is at risk of being compromised,” said Mariette Liefferink, the chief executive of the Federation for a Sustainable Environment.
‘On the backfoot’
In early February, the last of the basin’s three pumps that was still working, broke down, and the treatment plant was closed. But the problems had been “brewing” for some time, according to a highly-placed source at the department of water and sanitation who requested anonymity.
“We have three pumps in the Eastern basin. Each in theory should be able to produce about 30 million litres of AMD a day. We’re looking at a cumulative total of 90 million litres that should be pumped out.”
With only one pump working by February, “we were basically at 33% functional capacity. Two were out of commission. There was a spare pump but I believe it was almost like a spare tyre that you use between two or three cars … So, we were already on the back foot.
“We shouldn’t have allowed the plant to be operating with one pump … I’ve been raising these concerns for something like two years. I can raise the alarm bells but if nobody responds, it’s out of my control.”
Operating challenges
The water and sanitation department said it had been informed by the implementing agent, the Trans Caledon Tunnel Authority (TCTA), of the “operating challenges” and “remedial action” being taken.
The TCTA said it “fully appreciates the dangers posed by a prolonged closure of the plant” and is doing “everything in its power” to restore operations. In early April 2021, two pump motors broke down, leaving it operating on one pump.
“An additional spare motor was installed, increasing the capacity of the plant to 67% of its design capacity of 110 million litres per day, effectively pumping 70 million litres per day,” said Johann Claassens, executive manager of project management and implementation. “However, the spare motor only ran for two months, which once again left the plant operating on one pump.”
International travel restrictions meant that a technical team from Germany, dispatched by the supplier, Andritz, could only arrive in October, to assess the damage. After the assessment, spare parts for the failed motors were ordered and expected to arrive in December, with planned repair of the two pumps intended to be completed in February and March.
Supply chain challenges related to the Covid-19 lockdown mean the spares were not available for dispatch in December. The first batch of spares arrived in February and the repair to one pump commenced.
“Unfortunately, a further setback occurred when it was discovered that during the testing of the pump, before installation, the motor windings had failed, requiring complete rewiring of the motor,” he said. The copper wiring could only be delivered by the end of April, which will delay the recommissioning of the two pump sets to June, leaving the plant operations suspended until then.
‘Danger zone’
The Trans Caledon Tunnel Authority said that based on the initial assessment on the rise of the water level, “it is very unlikely that the water level, which is currently at 64.4m below ground surface, will rise above the danger zone of 25m by the time operations are resumed. “In the light of the current rate of rise, and if existing conditions prevail, it is estimated that this will not be reached earlier than December 2022.”
Water levels are rising significantly, the source said. “Two weeks ago, it was about 71m below surface … It’s quite frightening because, remember the project was commissioned with the strategic objective to hold the water at 120m below surface and now we’ve come to 64, 65-odd metres. Even allowing it to come to 80m was considered extremely risky …
“Already, even when the water was sitting somewhere in the order of about 80m [before the plant’s construction], although it’s fairly anecdotal, there was some evidence to suggest that a farmer in the Springs area had already been starting to observe a deterioration in water quality … with elevated levels of iron and sulphates. It is worrying if it is coming to 60m and hits the 50m mark.”
The situation is “disturbing”, the source said. “I’ve invested a lot of my time and my career in the department. Now to have it come to this, it’s almost like raising a child and giving it the best education only for them to become a complete drop-out altogether.”
Restore pumping urgently
An April 2022 report commissioned by Gravelotte Gold Mine on the geotechnical concerns related to flooding, noted how the rising water level in the area “directly influences the stability and ability to safely mine. Stability concerns regarding both underground operations, as well as surface infrastructure are now at play”.
Should pumping not be restored as a matter of urgency, Gravelotte “will run the risk of not having an ore resource to mine”, it said, stating “no increase in rising levels should be tolerated”.
“If the water floods the mine workings, then the mines cannot continue and many people may lose their jobs,” Liefferink said.
‘It’s unthinkable’
Democratic Alliance environment oversight councillor Jill Humphries said: “The water is rising so rapidly and that’s the concern. It’s unthinkable …. We cannot allow the water to rise in the way that it is, unchecked, in Ekurhuleni. Everybody has to step in and do something about it.”
Philip de Jager, the chairperson of the Grootvaly Blesbokspruit Conservation Trust, said: “These are massive expensive pumps, which taxpayers paid for, but there doesn’t seem to be any urgency involved.”
If there is a decant in December, it would probably report in Nigel because of the area’s topography, and where there are gold mine workings, the source said.
A 2015 report by environmental consultants Digby Wells Environmental described how, should decant occur, about 100 million litres a day of acid mine water is expected to flow into the Blesbokspruit, a Ramsar wetland.
“The release of this volume of raw acid mine drainage would result in irreversible impacts to the ecology in and around the Blesbokspruit and downstream catchments. Furthermore, downstream water users would be impacted due to poor water quality, together with expected infrastructure damage to nearby properties.”
The main concern, Liefferink added, is “that we were never informed. We attend the Blesbokspruit catchment management forum meetings quarterly and this was not reported to us, as the main stakeholders in the Springs and Nigel area”.
The City of Ekurhuleni said it was only made aware of the situation last Thursday. It would be requesting reports from the department of mineral resources and energy “regarding their plans to prevent the basin from decanting acid mine water” and to conduct an environmental impact assessment of a “possible spillage”.
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