The unit of Anglo American Plc said on Thursday that Miller will replace Natascha Viljoen, who is leaving for gold miner Newmont Corp, as CEO from Oct. 1.
Shares in Anglo Platinum (Amplats) rose 2% by 0758 GMT.
Miller has been finance director since 2019 and takes the helm after the company reported on Monday a 71% slump in first-half profit, hit by weaker platinum group metal prices, poor metal grades, rising costs due to high inflation and challenges at its flagship Mogalakwena mine.
"We must remain agile, adapting to market realities while focusing on efficiency and prudent resource management," Miller said in a statement.
Amplats' shares have fallen 36% this year. The Johannesburg-based miner and its South African peers are battling debilitating power outages that are threatening growth in Africa's most industrialized economy.
Miller, a chartered accountant, is an insider at Anglo American having also worked in the base metals and bulk commodities businesses at the group.
Still, he faces the challenge of finding solutions to expand Amplats' giant open-pit Mogalakwena mine, where the company has been exploring options to start digging for the metals underground.
Viljoen took over in 2020 and became the first female CEO to run the platinum miner.
(Reporting by Yadarisa Shabong in Bengaluru and Nelson Banya in Harare and Felix Njini in Nairobi; editing by Sonia Cheema, Jason Neely and Susan Fenton)
By Nelson Banya
