The 18 February 2025 TSF failure at Chambishi in Zambia (2025)

The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

On 18 February 2025, a major tailings storage facility (TSF) failure occurred at a Sino Metals facility near to Chambishi in Zambia. There has been little news reporting about this failure, but ZNBC has some coverage about the resultant pollution and potential government action.

The best reporting has come from a local tailings engineer, Holy Pola, who has posted a number of pieces about the event on LinkedIn. This includes some video of the release occurring and drone footage of the aftermath.

Based on the drone footage, Holy has made this assessment of the failure:-

“The failure was a cascading failure which was as a result of a piping that developed through the divisional wall between the two upper compartments, triggering a wall collapse (the fresh packed wall in the video). The supernatant water from the active compartment inundated the second inactive compartment with no operational freeboard causing an overtopping event that breached the wall, flowing into the third lower compartment. A huge amount of solids were mobilised from the third compartment into the fourth and fifth lowest compartments which then breached into the environment.”

The location of the Chambishi TSF failure is [-12.64647, 28.03397]. This is a Planet image of the site before the failure:-

And this is an image after the failure, captured yesterday:-

The Chambishi TSF is located in the northwest corner of the images – the multiple cells to which Holy Pola refers are clear. The most obvious element of the post-failure image is the plume of pollution that runs roughly north-south across the image, representing acidic mine waste that has been released from the TSF. This is visible when the images are compared with a slider:-

It is also worth taking a more detailed look at the Chambishi TSF itself after the failure:-

The cell located furthest to the west appears to be intact, but there is a clear breach in the containment between the next cell and the one to the east. This confirms Holy Pola’s suggestion that the failure occurred when the containment between the second and third cell collapsed, causing a cascade that ultimately led to overtopping and the release of the tailings.

I have noted many times before on this blog that the failure rate of TSF’s is unacceptably high, given their consequence. For now, the priorities at Chambishi need to be to prevent any more tailings from escaping, to contain the waste that has entered the environment, to compensate the landowners whose fields have ben destroyed and to improve the safety of this various TSFs in this area.

Reference

Planet Team, 2025. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

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