A 58km stretch of the lower Wilge River system is “dead” after an old coal mine in Mpumalanga decanted millions of litres of acidic water into the river system last week. (Wikipedia)
A 58km stretch of the lower Wilge River system is “dead” after an old coal mine in Mpumalanga decanted millions of litres of acidic water into the river system last week.
Tons of fish were wiped out within days by the acid mine drainage (AMD) from Thungela Resources’ Khwezela Colliery’s Kromdraai site, outside eMalahleni, which was detected on 14 February. Initial investigations have determined that a concrete seal at its south shaft failed. By February 20, the pollution plume had reached the Loskop Dam, killing scores of fish.
AMD is the spillage of toxic, polluted water from mining areas, which carries metals, radionuclides (atoms that emit radiation) and salts in concentrations that are hazardous to all forms of life.
The spill started in the Kromdraaispruit, poured into the Saalboomspruit, then into the Wilge River, which leads into the Olifants River and then reached the Loskop Dam.
“It’s 58km and 100% loss,” said Francois Roux, an aquatic scientist at the Mpumalanga Parks and Tourism Agency (MPTA). “All fish, all the macroinvertebrates, all life is gone … everything is dead,” he said, describing how 22 fish species had perished.
“And we’re not talking about otters, the birds and everything else … All of this pollution has ended up in the Loskop Dam Nature Reserve where we’ve got high species diversity and where we focus a lot of our conservation efforts.”
Rehabilitation will be long-term
Thungela Resources was formerly owned by Anglo American under its thermal coal business unit until a demerger last year. The mine where the decant unfolded, Roux said, is due for closure.
“It [the spill] started on Monday. On Tuesday it was reported and they were given a verbal directive from the department of water and sanitation to solve it. Not much happened. Then on Wednesday, a written directive was given to them. And then we were informed of the masses of fish dying off in the Wilge River,” he said.
“On Sunday, we instructed them to seal it off and pump it back to one of their shafts and they are complying at present. They need to put up a trust fund immediately because we’re going to have to go into the rehabilitation of the rivers, which is a long-term project … There’s still a lot of pockets of AMD sitting in the river.”
The damage, Roux said, will be long-lasting. “We’re going to sit for years with problems because these metals sit in the sediments and at different temperatures and chemical conditions, they mobilise again.”
Mpumi Sithole, the executive head of corporate affairs at Thungela Resources, said it is “devastated” by the disastrous effect on the environment. “We are fully committed to responsible management of water resources and will do what is in our power to take corrective steps. We are collaborating with various independent biodiversity, environmental and water experts to ensure we do what is right.”
Loskop Dam contamination
On Monday, Roux flew in a helicopter over the Loskop Dam and the mine. The sight of dead fish floating in the dam moved him to tears, he said. “It was just a total loss. It’s basically just fish floating all over the show. I found some hippos and crocs up there. They seem to be fine but we’re very worried about the crocs at present.”
In September, the MPTA released 24 crocodiles into the nature reserve. “We thought everything was fine after considering the water quality and then — bang. So now we’re back to square one. We will, within the next week or two, try to capture some, put satellite transponders on them so that we can follow them and see … if they are dying.
“We need to get all the fish out of the system as soon as possible because if you get fish like that, which are poisoned with all the heavy metals, all your fish eagles and vultures everything that picks up that fish, it [the contamination] will go into the next generation and cause infertility and all those things.”
‘No picture can do this disaster justice’
Another aquatic scientist, who asked not to be named, said: “No picture can show what is really going on. I’ve been working on rivers and in conservation for 43 years and I’ve never seen a big spill like this. I started crying when I saw it.”
Samples have been sent for testing to Onderstepoort. “It’s not one or two fish species involved — it’s all species,” he said, including papermouth, yellowfish and dolphin fish. “I’ve never seen a spill where you see the smallest of fish from the biggest of fish already dead. Some are still dying. It’s just incredible as the plume goes on, you just see the fish trying to get away and dying … This river will not be okay again for between 10, 15 and 20 years.”
Sithole said on 14 February, Thungela Resources became aware of an uncontrolled release of “mine-impacted water” at Khwezela Colliery. The incident took place at the south shaft, which forms part of an old mine that was last operational in 1966.
The shaft had been sealed since 2019 as part of the company’s water management strategy. “Despite a water management plan in place, the volume of water exceeded the maximum capacity for treatment at the dosing site and flowed into the Kromdraaispruit resulting in lowered pH levels of the water.”
As a company with environmental care at the “very top” of its business agenda, it viewed “this event with the utmost seriousness”, she said.
After it became aware of the contamination, Thukela reported the incident to the department of water and sanitation and the department of mineral resources and energy; performed water sampling and analysis upstream and downstream of the site; conducted water treatment at the discharge point; did independent sampling downstream; and monitored biodiversity.
“Following water treatment interventions, the results from water tests indicated that pH acidity levels in the Wilge River were at acceptable levels by the morning of 15 February. Testing continued throughout the week to monitor the situation.”
On 17 February, the water and sanitation department issued a directive with requisite actions “that forms part of our remedial actions. However, late on Sunday, February 20, we established that pH levels of the Olifants River where it meets the Loskop Dam, had dropped”.
She said preliminary indications are that lower pH levels “may be due to secondary factors such as the dissolution of metals, which would be present in historically contaminated river sediments”.
The overflow has now been contained. “Clean-up efforts are underway through collaboration with the MPTA, the farming community and other stakeholders. We have started working on longer term actions and those will entail re-establishing the ecosystem through the re-introduction of affected species and effective biomonitoring.”
No criminal case
The spokesperson for the water and sanitation department, Sputnik Ratau, said it is “taking appropriate actions, with engagements with the mine and affected parties. The mine has acknowledged culpability. Where the situation is right now is that there is a decision to release water from the Loskop, Wilge and Middelburg dams in order to flush the pollution.
“This will determine how much water will be required for this action, and then a determination of the cost of such water will also be determined and that money will be reimbursed by the mine to the department.”
He said there was no reason for a criminal case to be opened. “A criminal case is only opened as a very last resort where the polluter has not responded in any positive way to the compliance requirements.”
Cara Stokes, the chairperson of Bronkhorspruit Catchment Management Forum, described the contamination as a tragedy. “There are lessons to be learnt and underlying issues to the incident that we can’t see currently. Our slow transition to renewable energy drives the issue of AMD further.”