EMALAHLENI - About 350 jobs are at risk at Ferroglobe's eMalahleni smelter.
The Mpumalanga plant is moving closer to a possible shutdown due to rising electricity costs.
The smelter has been operating for around a century and warned earlier this year, that it may be forced to halt operations unless power costs are reduced.
Ferroglobe's energy-intensive furnaces rely heavily on electricity, making current tariffs difficult to sustain.
The company has been engaging government, Eskom and other stakeholders in search of a long-term solution.
A final closure decision has not yet been announced. But the potential shutdown has renewed concerns about the impact of high electricity prices, on South Africa's manufacturing sector and local jobs.