[DATA HAR: Harmony Gold] consultations are aimed at lowering costs and returning the operation to productivity.
It has begun a "Section 189" consultative process with unions and the government about job cuts at Kusasalethu, where it employs about 6,300 workers, Harmony said in a statement.
(READ MORE: Harmony to remain competitive in tough times)
The mine has posted losses since 2012.
"The current situation is clearly unsustainable," the company said.
Job cuts are a thorny issue in South Africa, where the jobless rate is around 25 percent and income disparities rooted in the apartheid era remain glaring.
(READ MORE: S.Africa seeks to revamp disused gold mines)
Improvement initiatives and investment injected into the Kusasalethu mine have been fruitless, the company said, adding that the "new plan will entail mining lower volumes at higher grades at a reduced cost".
"Harmony's intention is to restore the mine to profitability in the fourth quarter of the current financial year," Harmony said.