Brazilian authorities investigating last week's fatal collapse of a mine-waste reservoir have ordered operator Samarco to take emergency measures to deal with the catastrophic aftermath.
The announcement came as officials said at least six people were killed in the disaster, raising an earlier death toll of four. Twenty-one people remain missing and 631 displaced.
The company, a joint venture between Australian mining giant BHP Billiton and Brazil's Vale, has been issued a court order requiring it to collect and preserve evidence related to the dike failures that triggered the deadly mudslide, prosecutors say.
The measure is aimed at ensuring victims can obtain compensation for the environmental and human damage the incident is causing in the state, prosecutors said on Tuesday.
The firm must also provide a helicopter for an indefinite period of time to inspect areas of the state affected by the nearly 60 million cubic metres of ochre sludge.
Samarco will face a daily fine of 50,000 reals (about $A18,500) if it fails to comply.
The mud and mining waste burst through the retaining walls at the Samarco iron ore mine on Thursday and flattened most of the nearby village of Bento Rodrigues, in the state of Minas Gerais.
Fears were mounting that the sludge, which has flowed into local rivers, could contaminate the water supplies of more than half a million people in Minas Gerais and neighbouring Espirito Santo.
Residents in the area complained of a strong chemical smell coming from the local water. They posted photos on social media of ruined plantations and dead wildlife, including fish and turtles smothered in mud.
Authorities in Minas Gerais have ordered Samarco to halt operations. The company has put 85 per cent of its employees in the two states on paid leave.
The sludge, which has already flowed 400 kilometres, is expected to reach Espirito Santo on Tuesday.
The court order also requires state officials in Espirito Santo to test the water of the Rio Doce river for contamination.
Shares in BHP Billiton and Vale have fallen sharply since the disaster.
BHP Billiton's chief executive Andrew Mackenzie was due to visit the affected area "to understand first-hand the human, environmental and operational impacts of the incident", the company said.
The clean-up could cost more than $US1 billion ($A1.42 billion), Deutsche Bank analysts have warned.
Carlos Eduardo Ferreira Pinto, a state prosecutor specialising in environmental cases, alleged there was "negligence" involved.
"A dike doesn't break by chance. The responsibility of the company is key," he told the Globo television network.
"Prosecutors are now trying to judge the scale of the damage so that the public can be compensated."
Ratings agencies warned that the cut in iron and mineral production after the accident, as well as possible fines it could face if sued, threatened Samarco's position.
Moody's stripped Samarco of its investment-grade credit score, while Fitch put the firm on negative watch for a possible downgrade.
Threatening legal action, the state prosecution service in Minas Gerais called for Samarco to start paying to re-house displaced families and to help them start rebuilding their lives.
Share
