While tailings dams are meant to last for ever, extreme weather events are making many unstable – with devastating consequences for nature a
– with devastating consequences for nature and humans. As soon as the barrier broke, a flood of poison brought death to the river. Gushing through the fragile wall built to hold back mining waste in Zambia’s copper belt in February 2025, more than 50m cubic litres of acid and heavy metals poured into the Chambishi stream – a tributary of the Kafue River, the country’s longest waterway. Thousands of lifeless fish rose to the surface as a plume of acid floated downriver, leaving dead crocodiles and other wildlife in its wake. For the millions of Zambians that depend on the Kafue, the tailings dam collapse at the Chinese state-owned Sino-Metals Leach copper mine triggered a national environmental emergency that is yet to end. The spill shut down drinking water supplies for Kitwe, Zambia’s third-largest city, home to half a million people. Signs of pollution were detected 60 miles downstream from the collapse. Helicopters chased the spill downriver, dropping lime into the water in an attempt to neutralise its corrosive potency.-The affected region is home to rare wildlife, including the Kafue lechwe antelope, the Zambian barbet bird, and the wattled Crane. “It looked like diesel mixed with oil. We had already planted our crops, but they died. When you now turn up the soil to till it for planting, it has become yellowish and has a pungent smell,” says Mary Milimo, a 65-year-old smallholder close to where the Mwambashi River joins the Kafue. “There are no more fish here,” says Patrick Chindemwa, 66, who farms nearby. “I planted maize in October using irrigation. All the maize dried up. “The ground is yellow and soil here is like grease; it is slippery and when it rains, it melts. We need help,” he says. Sino-Metals did not respond to a request for comment. Almost a year later, the Kafue disaster has become yet another black mark against the mining industry and its long history of environmental disasters caused by poorly stored waste. Tailings dams – repositories of mining waste that is often toxic and stored under water – litter landscapes around the world. Often, they hold huge quantities of poisonous, harmful material.
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