SYDNEY, Nov 30 (Reuters) - BHP Billiton said on Monday its chairman and three other board members would oversee its response to the Samarco mine disaster in Brazil as clean-up efforts continue amid confirmation arsenic had been found in river water.
BHP, which formed a sub-committee to assist the board in its management of the events at Samarco, has already vowed to establish a fund to help pay for recovery work on the Rio Dolce river system, polluted by the mine's runoff.
The four-member sub-committee will include BHP chairman Jac Nasser, it said. Nasser sought to assure shareholders at BHP's annual meeting earlier this month that he was committed to getting Samarco back on its feet.
Brazil's federal and state governments on Friday announced plans to sue Samarco's co-owners, BHP and Brazilian miner Vale , for 20 billion reais ($5.24 billion) in damages as early as Monday.
The proceeds would be put in a fund and used for an environmental cleanup in the Rio Doce valley over 10 years, according to Attorney General Luís Inácio Adams.
BHP in a statement said it had yet to receive formal notice of the action.
Samarco has already been fined 250 million reais by Brazil's environmental agency, Ibama, for the disaster, which covered the flood plain in mud for 80 kilometers (50 miles). Fish died and drinking water supplies for a quarter of a million people had to be closed off.
Vale confirmed some tests detected toxic elements in the river after the dam was breached. Samarco was operating the dam when it burst on Nov. 5, triggering a mudslide that wiped out a nearby town and flooded the river. (Reporting by James Regan; Editing by Richard Pullin)