Canadian Malartic tailings dam. Courtesy of Agnico Eagle

The failure of the Córrego do Feijão dam was as sudden as it was devastating. Cracks appeared in the wall and in mere seconds it crumpled. A cloud of brown dust exploded into the air as the wall gave way to a torrent of mud that moved too fast to trigger an alarm and enveloped everything in its path. Videos, released days after the fact, showed buildings and vehicles quickly submerged.