Rio Tinto has suspended a senior executive after a $US10.5 million payment linked to a project approval in Africa.

Former Rio Tinto energy and minerals chief executive Alan Davies had accountability for the Simandou project in the nation of Guinea.

Mr Davies was suspended after investigations found that $US10.5 million in payments had occurred in 2011, the same year it signed a major agreement with the Government of Guinea about the project.

The evidence included emails from 2011 relating to “contractual payments” made to a ‘consultant’ on the Simandou project.

The agreement would see a Rio Tinto subsidiary, Simfer, pay the Government of Guinea $US700 million.

Rio Tinto told shareholders at the time that the agreement “secures Rio Tinto's mining title in Guinea and paves the way for first shipment of iron ore by mid-2015”.

The company praised the Government of Guinea for working “so constructively”, and for its commitment to the Extractive Industries Transparency Initiative.

Rio Tinto now say it found out about the money transfers using external investigators, who discovered information that the company said warranted alerting authorities in United Kingdom, United States.

Rio Tinto is “in the process” of contacting Australian authorities.

Analysts say any damage to the company would likely be reputational, but not monetary.

It is the latest chapter in company’s fraught history with the project.