Efforts to find remaining survivors ramped up in towns devastated by the collapse of a huge dam that released a torrent of muddy iron ore waste in southeast Brazil. On Friday, the dam, owned by the Brazilian mining company Vale, collapsed near the town of Brumadinho, sending tons of sludge down the valley below, damaging or destroying houses, farms, and vehicles. At the moment, authorities have reported at least 60 deaths, with another 290 people still listed as missing—and warnings have been issued about another dam nearby that is also at risk of failure.