SAO PAULO (Reuters) - Brazilian mining company Samarco Mineração SA and owners Vale SA <VALE5.SA> and BHP Billiton Plc <BLT.L> have hired banks to sound out creditors on a potential renegotiation of $3.8 billion in debt, after a deadly dam spill led to the shutdown of a key mine, a source with direct knowledge of the plan said on Monday.

According to the source, BHP Billiton has hired Rothschild & Co as an advisor on the deal, Vale has brought in Moelis & Co <MC.N>, and JPMorgan Chase & Co <JPM.N> is advising Samarco. The source asked for anonymity because the process is private.

Neither Samarco nor Vale or BHP Billiton has drafted any proposal to creditors, because the talks will hinge on when Samarco's iron ore mine in the state of Minas Gerais will be allowed to restart, the source said.

Bloomberg News first reported the hiring of the banks on Sunday.

The burst tailings dam at the mine on Nov. 5 unleashed a mud flow that killed 19 people, left hundreds homeless and polluted a major river. The government called it the country's worst ever environmental disaster.

The mine has been closed since. Environmental authorities say it will only be allowed to reopen when it can prove mud is no longer leaking into the surrounding area and that the mine can be run safely.

Vale, BHP and Samarco declined to comment. Rothschild, JPMorgan and Moelis did not immediately respond to requests for comment.

UNREALISTIC TIMELINE

Samarco initially expected to resume operations this year, but admitted last week that the timeline was no longer realistic.

FTI Consulting Inc <FCN.N> has been also hired as adviser for banks which are owed about $1.6 billion by Samarco, the source added. The remaining $2.2 billion are owed to bondholders, the source noted. FTI declined to comment.

The company has proposed restarting production at limited capacity and using old mining pits to store tailings. This proposal is still being considered by local authorities who have not indicated when or if they will be approved.

Samarco's 5.375 percent dollar-denominated bond maturing in September 2024 <79586KAD3=> rose on Monday, adding 0.75 cents on the dollar to 47 cents. The bond has lost almost half its value since the November spill.

(Reporting by Tatiana Bautzer; Additional reporting by Stephen Eisenhammer in Rio de Janeiro and Barbara Lewis in Brussels; Editing by Guillermo Parra-Bernal and Andrew Hay)