The collapse of a structure holding mining waste slurry, whose severity comes from the near-liquid flow of the released material.
A tailings dam retains the slurry left by ore processing, a mixture of water and fine particles that behaves on failure not as an earth slide but as a fluid, traveling fast and far. That is what explains the gap between the modest appearance of the structure and the scale of the human losses. Two features make the risk distinctive. The structure grows throughout the life of the mine, often by raising the embankment upstream, the cheapest technique and the one most exposed to liquefaction. And it survives the closure of the mine, with no operator and no revenue to maintain it, creating a liability of indefinite duration. The loss then combines property damage, mass liability, environmental harm and claims against directors, an exposure the mining sector's usual limits rarely match. Since the recent disasters, underwriting has relied on an industry standard imposing classification of structures and a named engineer of record.
The failure of the tailings dam at the Córrego do Feijão mine in Brumadinho, Brazil, on 25 January 2019, killed more than two hundred and fifty people and led to a compensation agreement with the State of Minas Gerais in February 2021.
tailings dam failure, barrage de stériles, digue à stériles, rupture de barrage minier