Mining Impacts · impact
Tailings dam failure
Ground · Both
- Category
- Ground
- Timescale
- Both
Mitigation
Downstream or centreline construction instead of upstream raises, dewatered or thickened tailings, piezometer monitoring, and independent review of the design.
Case
Brumadinho, Brazil, 25 January 2019: a Vale iron ore dam failed without warning and killed about 270 people. Fundão at Mariana, 5 November 2015, killed 19 and carried tailings down 668 km of watercourse.
Mechanism
Tailings are stored wet behind embankments often built from the tailings themselves. Saturated fine material can liquefy — losing its strength and flowing like a liquid — under a rise in the water table, an earthquake, or simply the slow creep of an over-steep upstream-raised wall.
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