Chambishi Mine Pollutes Kafue River Basin

On February 18th, 2025, an accident occurred at Sino Metals’ Leach Zambia Limited Tailings Dam 15F in Chambishi, Copperbelt, releasing more than 50 million liters of acidic effluent (concentrated acid, dissolved solids, and heavy metals) into the Mwambashi River, a tributary of the Kafue River.

For context, Sino Metals Leach Zambia Ltd produces copper cathodes on the Copperbelt. A tailings dam is an earth-fill embankment dam used to store mining waste, such as rocks and minerals with no commercial value after the ore is processed to extract valuable minerals. Mine waste often contains a range of toxic elements that are harmful to human health and the environment and should be disposed with extreme caution. Unfortunately, the Chambishi accident represents the most recent episode of a growing list of tailings dam failures around the world.

The spill had immediate adverse effects on the surrounding region, causing severe pollution along the Kafue basin, killing all aquatic life in the rivers close to the dam, and contaminating surrounding farmlands, with extensive damage to maize and groundnut fields for over 200 farmers. The disaster also resulted in the suspension of water provision in Kalulushi and Kitwe and close schools and universities. Moreover, communities were warned not to consume any fish to avoid contamination.

In the aftermath of the accident, the government responded swiftly by, first, stopping the discharge of leach into the river by creating a barrier with waste rock and laterite, and then neutralizing the acid by spraying lime over the Mwambashi river and a 100-km stretch of the Kafue River. ZEMA (Zambia Environmental Management Agency) has been monitoring water quality levels. One week after the accident, MoGEE said the contamination levels from the mine had reduced and the standard of water normalised.

The government ordered Sino Metals to cease operations at the tailing dam until necessary repairs are completed. Sino Metals have expressed regret over the incident and committed to compensating affected farmers. ZEMA has also tasked the company with the rehabilitation of contaminated areas, including soil restoration and reforestation.