The water use licenses, which also include mines run by South32 Ltd. and Exxaro Resources Ltd., were assessed in a report by the Centre for Environmental Rights. The study found “gross violations and water pollution by the operators,” it said.

South Africa, the most industrialized nation on the continent, uses coal for more than 90% of its electricity generation. While environmental groups have raised awareness of premature deaths caused by power plant pollution, the new study found “massive failures” by the Department of Water & Sanitation to effectively regulate water licenses.

“The pollution of South Africa’s precious water resources occurs on a particularly egregious scale in areas with high levels of mining activity,” according to the report. “The mining of coal is particularly harmful, with acid mine drainage from coal mines polluting surface and groundwater with acid, salts and metals.”

Glencore, Anglo American and South32 said they plan to respond to the report. Exxaro and the Department of Water didn’t immediately respond to emails seeking comment. DM