Insurers covering risks for a Brazilian mine where two dams burst last week, killing at least six people, could pay up to $600 million in claims, a source with direct knowledge of the matter said on Monday.

A property policy held by the dams’ owner, Samarco Mineração SA, could cover up to $90 million in related claims, said the source, who requested anonymity because terms of policies remain confidential.

A separate policy for so-called business interruption events could pay as much as $510 million if the joint venture between BHP Billiton Ltd and Vale SA proves that it lost that much in profits, the source added. It is unclear how the miner agreed on the $510 million figure with its insurers, led by ACE Ltd.

Samarco, which operates as an independent mining firm in the Brazilian iron one-rich state of Minas Gerais, earned 2.8 billion Brazilian real ($747 million) in net income last year. The venture produces 30 million tonnes of iron ore annually, or about 2 percent of global capacity.

Experts could take at least 90 days to investigate the causes of the disaster in southeast Brazil, a second source said, adding that the owners face a lengthy process of calculating lost profits from the flood, which left 21 people missing.

The lead underwriter of the combined property and business interruption policies is Zurich-based ACE, which is liable to pay 80 percent of the amount covered, the source added. Spain’s Mapfre SA and Canada’s Fairfax Financial Holdings Inc also form part of the team of underwriters, the source added.

Germany’s Allianz SE provides the venture with a separate policy for civil liabilities, which had a coverage of about 70 million reais as of June 2014, according to a Samarco bond prospectus. The second source said that such coverage could be “too small” to pay for extensive environmental damage, let alone what courts decide as compensation for families of the victims.

That potential shortcoming could fuel investors doubts about whether Samarco has enough insurance to cover all of the disaster costs. It also remains unclear whether there is any scope for the cost of the damages to spread to other entities such as builders or state entities, as well as BHP and Vale.

While the size and extent of damages are still to be determined, the dam collapse will have a “meaningful impact” on insurers and reinsurers operating in Brazil, said Diego Kashiwakura, an analyst with Moody’s Investors Service.

Moody’s on Tuesday cut Samarco’s bonds to junk, saying they remain on review for further downgrade.

A spokesman for ACE in São Paulo said the company does not comment on “specific risks,” while Allianz declined to comment. Fairfax and Mapfre confirmed they are in the pool of underwriters, but declined to elaborate.

Willis Group Holdings Plc confirmed to Reuters that it acted as the broker for the Samarco policy.

Samarco did not comment on insuring policies.

Bonds Plunge

The extent of the dam burst and subsequent flooding, which wiped out a nearby village and still risks flooding neighboring towns, raises questions about the future of Samarco’s ore operation in Brazil, where two of the mine’s three waste-containment dams burst.

The price on Samarco’s 5.375 percent bond maturing in September, 2024 slumped to 60 cents on the dollar on Tuesday from 87 cents on Nov. 5, a day before the collapse.

Large insurers have tried to increase their presence in Brazil, where large oil and infrastructure projects took off at the start of the decade. Last year, ACE paid 1.5 billion reais for the high-risk insurance portfolio from Itaú Unibanco Holding SA, Brazil’s largest bank by market value, in a bold move toward raising exposure to Latin America’s largest economy.

The operating license for the mine has been revoked by the Minas Gerais state government. The flooding has forced more than 600 people to be evacuated. ($1 = 3.7489 Brazilian reais).