In January 2019, a dam holding back mining sludge at the Córrego do Feijão iron ore mine in Brumadinho, southeastern Brazil, collapsed. Around 10 million cubic meters (2.6 billion gallons) of the liquefied waste, or tailings, burst out of the dam, flattening nearby settlements, destroying a railway bridge, sending a surge of toxic mud into the Paraopeba River. In all, the disaster killed 272 people. The company behind the dam, Vale S.A., Brazil’s biggest miner, was ordered to pay $7 billion in damages to the affected communities. The collapse caught many by surprise; it occurred without any warning, and three years after the mine had stopped dumping its tailings there. The dam had passed safety inspections, and had been equipped with state-of-the-art monitoring equipment. An investigative committee set up to understand what caused the breach concluded that the accident was likely due to imperceptible deformations of the sediment making up the dam, a phenomenon known in industry parlance as “creep.” But they were unable to describe the exact physical mechanism behind the idea. The Brumadinho iron mine before the tailings dam collapse. Image by midianinja on Visual hunt / CC BY-NC-SA Now, five years after the collapse, geotechnical engineering researchers at ETH Zurich, the Swiss federal institute of technology, have depicted the exact physical mechanisms that caused the catastrophic collapse. Their findings, published in the journal Communications of Earth & Environment, detail a new model for risk analysis that could make both active and closed dams safer. “A dam is a…This article was originally published on Mongabay
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