Five BHP tailings facilities pose 'extreme' risk

Five of Anglo-Australian mining firm BHP's tailings facilities have been classified as posing an "extreme risk" to surrounding communities in the event of a collapse, while a further 16 are said to pose a "very high risk".

The dams were ranked according to the Canadian Dam Association (CDA) Consequence Classification ratings. Of those posing an extreme risk, one is in the US and four are in Australia. Two are inactive, but the tailings dams at Whaleback in Western Australia and Olympic Dam in South Australia remain active.

The facilities ranked very high risk are located in Australia, Chile, Canada and the US, five of which are in Arizona.

Facilities at two non-operated joint ventures — Antamina in Peru and Samarco-Germano in Brazil — were also rated an extreme risk.

BHP commissioned the risk assessment after two high-profile collapses at Brazilian tailings dams resulted in the deaths of hundreds of people and severely disrupted iron ore mining operations, causing global supply concerns.

In November 2015, the Fundao tailings facility at the Samarco complex — a joint venture between BHP and Brazil's

Vale — ruptured, killing 19 people and causing one of Brazil's worst environmental disasters. Last month, Samarco announced plans to restart operations at the mines using new waste-processing technology.

Vale became the subject of further controversy in Brazil in January when the Brumadinho dam collapsed at the Corrego do Feijao iron ore mine, killing hundreds of people and devastating the surrounding environment.