Rio Tinto will pay $US15 million ($22 million) to settle a long-running US probe into payments to a Guinean political adviser, ending a saga that prompted the exit of two senior executives and caused the company more than six years of reputational damage.

The Securities Exchange Commission said on Tuesday that the political adviser hired by Rio in 2011 to help secure access to the Simandou iron ore province had “attempted to make an improper payment” to a Guinean government official.