Energy Resources of Australia's chief executive Andrea Sutton is stepping down from the uranium miner to join parent company Rio Tinto.
ERA on Friday said Ms Sutton, who took over the role of managing director and CEO in September 2013, had informed the board of her intention to resign in order to accept a role within Rio Tinto.
The company did not provide details of her new position.
ERA said a search for her replacement will start immediately, while Ms Sutton will work with the board to ensure a smooth transition to her successor.
The miner last year outlined its plan to produce uranium only from stockpiled ore at its Ranger mine in the Northern Territory after Aboriginal land owners refused to back the renewal of its mining authority beyond 2021.
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The ore stockpile is due to run down by the end of 2020, and ERA is using sales to raise cash for funding the rehabilitation of the Ranger mine, which is surrounded by the World Heritage-listed Kakadu National Park.
ERA has estimated a $507 million bill to clean up the site, which Rio has offered to cover in case of any shortfall.
Rio Tinto, which owns majority stake in the company, in 2015 declined to invest in studies for an underground expansion of the Ranger mine, amid a slump in uranium prices.
At 1552 AEDT, ERA shares were up 2.9 per cent at 72 cents each.
