The Environmental Crisis of Tailings Dams: A Global Concern

In February 2025, a catastrophic failure of a tailings dam in Zambia's copper belt released over 50 million cubic liters of toxic waste into the Chambishi stream, a tributary of the Kafue River. This incident resulted in the death of thousands of fish and wildlife, including crocodiles, and severely impacted the drinking water supply for Kitwe, Zambia's third-largest city, which is home to approximately half a million residents. Local farmers reported devastating losses, with crops dying and soil becoming contaminated and unfit for agriculture. Mary Milimo, a local smallholder, described the soil as "yellowish" with a "pungent smell," while Patrick Chindemwa lamented the loss of his maize crop due to the pollution.

The Guardian

Tailings dams are engineered structures designed to store mining waste, often containing hazardous materials such as heavy metals. While they are intended to be permanent, the increasing frequency of extreme weather events due to climate change has raised concerns about their stability. Experts warn that many tailings dams are located in ecologically sensitive areas, with at least 108 identified in key biodiversity zones globally. The failure of such dams can lead to catastrophic environmental consequences, as seen in previous incidents like the Brumadinho disaster in Brazil, which resulted in 272 fatalities and extensive ecological damage.

The Guardian

In the wake of the Brumadinho disaster, the mining industry has begun to adopt improved safety standards for tailings management. Emma Gagen, research director at the International Council on Mining and Metals (ICMM), noted that the industry has developed a comprehensive 77-point standard aimed at enhancing safety protocols. However, she acknowledged that many mining companies are not ICMM members, and compliance with these standards remains inconsistent. Institutional investors, including the Church of England’s pension fund, are advocating for greater transparency and accountability in tailings management.

The Guardian

Despite these efforts, critics argue that the mining industry continues to prioritize profit over environmental safety. Prof. Elaine Baker, a marine scientist, emphasized the need for perpetual maintenance of tailings dams, warning that the current practices resemble those of ancient mining methods. She highlighted the alarming presence of tailings dams in protected areas, stating that "the industry goes where it wants to go, wherever they find deposits." This sentiment reflects a broader concern that without significant reforms, the risk of future disasters will remain high.

The Guardian

While the Zambian authorities conducted an investigation into the Kafue disaster, findings revealed a lack of qualified engineering oversight in the dam's management. Cracks and uncompacted walls were noted, raising questions about the adequacy of safety measures in place. The discrepancy in the management of tailings dams across different regions and companies highlights a critical gap in the industry's commitment to environmental stewardship.

The Guardian

• “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,” — Mary Milimo, Local Farmer

The Guardian

• “They have to be maintained in perpetuity.” — Prof. Elaine Baker, Marine Scientist

The Guardian

• “Any loss of life from a tailings facility is unacceptable.” — Emma Gagen, Research Director, ICMM

The Guardian

• “Baker says: “There’s no reason why we’re seeing tailings dams in so many wilderness areas and protected areas.” — Prof. Elaine Baker, Marine Scientist

The Guardian

The ongoing challenges posed by tailings dams underscore the urgent need for comprehensive reforms in mining practices to safeguard both human and environmental health.

The Guardian