A dam holding back wastewater from the Germano iron ore mine near the city of Mariana in Minas Gerais state burst Thursday. Television footage showed a torrent of red muck several hundred meters long that had swamped houses and destroyed roofs in the touristic city of more than 50,000 people.

"The situation is grim. It is dark. There is a lot of mud," Fire Chief Adao Severino Junior said. "There is no way to survive under that material."

The neighboring village of Bento Rodrigues was completely buried, the chief added.

At least 17 people have reportedly been killed. More than 40 people are still missing. Others sat on roofs awaiting rescue as the muck enveloped residential streets.

The dam had been holding tailings, a mining waste product of metal filings, water and occasionally toxic chemicals. It was located near the Gualaxo do Norte River, adding to fears of contaminating waterways.

Mine owner Samarco, which is a international joint venture between Brazil's Vale and Australia's BHP Billiton, said in a statement it had not yet determined why the dam failed or the extent of the damage.

At least 600 people have been evacuated from the 17th century city known for its baroque architecture and churches. Flooding had also reportedly spread downhill to the village of Paracatu de Baixo, whose inhabitants have been evacuated.

Brazilian military troops stood ready to aid search and rescue efforts; the minister of national integration, Gilberto Occhi, planned to visit the state on Friday to provide assistance, according to a statement from the presidency.

The region had already been struggling amid a collapse in prices of iron ore and other commodities due to concerns about demand from China, which has hurt the mining concern's parent company.

jar/sms (AFP, Reuters)