The chief executive of Aquarius Platinum has resigned as pressure mounts across the South African precious metal industry, with falling prices and violent wage protests.
Stuart Murray, who has run the FTSE 250 company Aquarius for just over a decade, gave no public reason for his decision to quit.
His departure is the third major exit from a platinum miner this year. David Brown left Impala Platinum in January, and Neville Nicolau quit Anglo Platinum in July.
Lonmin's Ian Farmer stepped aside with long-term illness in August.
There is no immediate replacement for Mr Murray, who for much of his time was the only executive director on the board. Jean Nel, recently appointed commercial director, has been made chief operating officer.
Alison Turner, an analyst at Panmure Gordon, said: "The resignation is a sign of the depth of the challenge of operating a platinum company in arguably the toughest conditions ever faced by the industry."