Rio Tinto's unit Rio Tinto Exploration Pty. Ltd. completed the acquisition of a 51% stake in Antipa Minerals Ltd.'s Citadel gold project in Western Australia after sole funding over A$11 million of exploration expenditure on the project.

In a news release on Jan. 9, Antipa said that Rio Tinto has now assumed the operator role in the joint venture and has until Jan. 30 to decide whether to sole fund an additional A$14 million of exploration expenditure within three years to increase its interest in the project to 65%.

Subject to earning the 65% stake and Antipa not choosing to contribute to the expenditure, Rio Tinto gains the right to earn up to 75% stake in the project by sole funding an additional A$35 million within a further three years.