How Brumadinho disaster could push global change in tailings management

Tailings are a sand-like byproduct of mining activities which are the result of crushing ores before mineral extraction. Often, tailings are disposed of in dams built using more tailings, or other waste products. While technical knowledge exists to safely build these structures, failures of dams, with tragic consequences, are occurring at an unacceptably high rate.

There have been significantly destructive tailings dam collapses in countries such as South Africa, Japan, Italy, Canada—and, most recently, Brazil. In January 2019, a tailings dam at the Córrego do Feijão iron mine in the small Southeast town of Brumadinho, collapsed. According to the World Mine Tailings Failure database, this resulted in the release of 12 million cubic meters of sludge. It also killed 240 people. By May 2019, 32 were still listed as missing.

Its high death toll sets the Brumadinho failure apart from many others. The World Mine Tailings Failure database, which covers over a century of such incidents, contains only four failures with death tolls exceeding 250: Mexico in 1937, Bulgaria in 1966, Italy in 1985, and China in 2008.

So why do tailings dams fail? And what can we do to try and avoid these collapses? This is what we explored in a recent paper...