In February 2022, the Wilge River, was poisoned by a mass influx of acid mine drainage from an abandoned shaft owned by Thungela Resources, a JSE-listed thermal coal giant (formed by the demerger of Anglo American’s thermal coal operations in South Africa) and is issue 41’s Troubled Waters. The results were devastating. A year and a half after it happened, Matt Kennedy investigates the state of the river and the clean-up operation, finding more questions than answers. 


The Wilge River is a tributary in the greater Oliphants River catchment, originating in western Mpumalanga. It runs north-east from its source, which is hugged by coal mines from Kusile to Kromdraai, along a major coal belt in Mpumalanga. It then converges with the middle reaches of the Oliphants, which flows from Witbank, and continues into Loskop Dam some 15km northwards. 

The Wilge/Oliphants system’s indigenous fish diversity is impressive, with approximately 13 species and several exotics like bass and carp. The warmer downstream sections are prime habitats for largescale yellowfish, papermouth, and a variety of other labeo and tilapia species, while the cooler higher reaches include the bushveld smallscale yellows. Small and largescale yellows are unique to the north-east flowing Oliphants/Crocodile river systems in the Limpopo basins, related only by genus to the Vaal/Orange smallmouth and largemouth yellowfish. 


On 14 February 2022, an AMD spill occurred out of the Thungela Kromdraai colliery site, flowing directly into the Kromdraaispruit, a small tributary of the Wilge River. It went on for almost a week and by the time the Department of Water and Sanitation forced Thungela to do something about it, the damage was already done.  

The source of the spill was an abandoned and neglected shaft, previously operational in 1966. Ordinarily, water build-up is managed by a multi-level system which addresses water accumulation and decanting post-mining. A concrete barrier placed to seal the shaft failed and gave way to a torrent of acidic and metallic slurry – AMD.  

When flowing directly into a system in concentrations like this, AMD does not discriminate. Insects and fish in the river are directly intoxicated by the slurry and the die-off ensues immediately. High concentrations of sulphuric acid chemically burn the gills of aquatic creatures, inducing suffocation. Aquatic plant life and other riparian structure follow soon after, effectively corroding in the toxic water. 


It seems the way forward can be as simple or as complicated as those pulling the strings deem necessary.   

We tried to investigate various key role-players in the Wilge scenario, including the perspectives of the angler, the mine, and the science/conservationist crowd. Garth, the angler and passionate yellowfish conservationist, is upset about the disaster itself, but more so the lack of full transparency in the clean-up effort and the politics of the conservation authorities. 

Thungela, the mining company, has accepted responsibility, although we think they fail to satisfy any concerns about the Wilge’s recovery and prevention of these types of issues in future. The Mission sent Thungela several questions on the status of the river and their clean-up efforts a year after the incident. Although they offered a response, their answers (available for download in full below) are, in our opinion, both tightly vetted and purposefully vague. 

Read the rest of this Troubled Waters feature in issue 41. It’s free!

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