On 5th November 2015, the Fundão tailings dam, in the district of Mariana, State of Minas Gerais, Brazil, failed. It contained waste material from the Germano iron mine, managed by Samarco Society, a joint venture between the Anglo-Australian Bhp-Billington and the Brazilian Vale, which are two of the most important multinational mining companies worldwide.
A mudflow exceeding 30 million cubic metres struck the village of Bento Rodrigues, which was completely destroyed. In addition, the flow ran down the rivers Gualaxo do Norte, Carmel and Rio Doce for over 660 kilometres, eventually reaching the Atlantic Ocean about two weeks after failure.
There were 17 confirmed deaths, while two persons went missing.
15 square kilometres of soil were contaminated along the route of the mudflow and the supply of drinking water for 250,000 inhabitants was interrupted.
The failure of the Fundão tailings dam was due to insufficient drainage and liquefaction of the tailings sand shortly after a small earthquake. The Bento Rodrigues (or Mariana) disaster is considered the worst incident ever for environmental damage.