Cleary Gottlieb Steen & Hamilton has been appointed by BHP Billiton, Samarco and Vale to lead an external investigation into the recent Brazilian dam disaster which killed 17 people.

The US firm has been instructed by the companies to look into the cause of a breach in the Fundao tailings dam and the Santarem water dam, which burst at the Samarco Mineracao iron ore operation in Minas Gerais, Brazil on 5 November.

Mining giants BHP Billiton and Vale each hold a 50% interest in the operation.

Cleary's investigation will "draw on expertise in disciplines such as geotechnical engineering and hydrology", BHP Billiton said in a statement yesterday (22 December.)

17 deaths occurred in the accident, 12 workers and five members of the local community. Two people remain unaccounted for.

BHP Billiton, Samarco and Vale have also been the subject of proceedings commenced by the Brazilian government, which has ordered that Samarco pay $520m (£340m) into a government bank account within 30 days, or face a fine of $390m (£250,000) a day for every day it fails to do so.

A judge has also ordered that the companies must undertake remediation actions to prevent further environmental fallout from the breaches and must also present a plan for the affected region's socio-economic recovery.