Antipa Minerals Limited announced that Rio Tinto, by sole funding $11 million of exploration expenditure on the Company's Citadel Project, has earned an initial 51% interest in the Citadel Project and a joint venture between Rio Tinto and Antipa has now been formed. The Citadel Project comprises a 1,330km tenement package located in the prospective Paterson Province in northern Western Australia, 80km north of Newcrest's Telfer goldcoppersilver mine and 5km east of Rio Tinto's Winu copper gold silver deposit. The Citadel Project hosts a global Mineral Resource of 63.8Mt at 0.8g/t gold and 0.2% copper for 1.6Moz gold and 127kt copper. In accordance with the terms of the Citadel Project Farmin Agreement, Rio Tinto has now assumed operatorship of the Citadel Joint Venture and has until 30 January 2020 to elect whether to sole fund an additional $14 million of exploration expenditure within 3 years to increase its interest in the Citadel Joint Venture to 65%. Subject to Rio Tinto earning the 65% interest and Antipa then not electing to contribute to expenditure to maintain its 65% interest, Rio Tinto also has the ability to earn up to a 75% interest in the Citadel Joint Venture by sole funding a further $35 million within a further 3 years.