The dam that burst in south-eastern Brazil on Thursday devastated a nearby town with mudslides and left officials in the remote region scrambling to assess casualties.
Forty-five people were still missing after the disaster at the Germano mine near the town of Mariana in Minas Gerais state, a local union said.
The mine is operated by Samarco, a joint venture between the Anglo-Australian mining giant BHP Billiton and the Brazilian company Vale.
Andrew Mackenzie, the chief executive of BHP, said in Melbourne: “Most of what happened there has been under the cloak of darkness. At daybreak, clearly we will do an awful lot more and give you further updates.” The company would “take all steps” to ensure the safety of workers and communities affected by the disaster.
Video footage on the G1 website showed houses of a village destroyed by floodwater and clay-red mud that surged down valleys in the mountainous region. Large vehicles lay tossed on their sides.
There was no official confirmation on the total number of dead and missing. A city hall official confirmed one death and 16 injuries, adding that dozens more were still missing. Civil defence authorities in Mariana were evacuating about 600 people to higher ground from the village of Bento Rodrigues, about four miles beneath the dam that burst, which was flooded as a result of the accident.
Television footage showed dozens of homes destroyed by the mudslide. A car rested on top of a wall where the roof of a building had been ripped off.
Authorities said the flood had also reached another village further down the hill, Paracatu de Baixo, and that inhabitants there were also being evacuated.
Rescue crews continued to search the muddy waters after nightfall. Brazilian army units stood ready to help search and rescue efforts and the minister of national integration, Gilberto Occhi, planned to visit the state yesterday to provide assistance.
Samarco said in a statement it had not yet determined why the dam burst or the extent of the disaster.
BHP Billiton said in a statement that it was “concerned for the safety of employees and the local community ... We are in the process of obtaining more details from Samarco Mineracao.”