Rio Tinto faces SFO investigation into possible corruption

Last November the mining giant turned itself into authorities over worries about the Simandou iron ore project in the west African country and alleged $10.5m of bribery payments made to a contractor in 2011.

"The SFO has opened an investigation into suspected corruption in the conduct of business in the Republic of Guinea by the Rio Tinto group, its employees and others associated with it," the organisation said overnight.

In November, Rio Tinto terminated the contracts of two directors after an internal review into a controversial payment made to a consultant.

Energy and minerals chief executive Alan Davies and legal and regulatory affairs group executive Debra Valentine were said to have "failed to maintain the standards expected of them under our global code of conduct".

The Anglo-Australian mining giant said the board's decision "does not pre-judge the course of any external inquiries into this matter", having last week referred the matter to law enforcement authorities in the UK, the US and Australia.