At least 300 jobs are expected to be cut at mining contractor Goldings.
The job cuts are believed to be linked to the Whyalla Steelworks, which resumed operations last week after a four-month shutdown.
Last year, Steelworks parent company GFG Alliance announced plans to wind down its mining of hematite and shift its focus to magnetite ore.
It is understood that Goldings then decided to end part of its operations this week, despite originally planning to continue until mid-2025.
GFG confirmed in a statement today that it would be placing its mining operations at Iron Knob into ‘care and maintenance’.
The company said they would possibly look at the redeployment of staff into the Whyalla Steelworks.