Consolidated Minerals has announced its decision to suspend operations at its Woodie Woodie mine in Pilbara, Western Australia.
The company's latest move comes following record low prices for manganese ore.
Consolidated Minerals plans to cease all operations at Woodie Woodie by 2 February, and axe most positions at the mine site and in West Perth.
The company's decision will affect about 330 direct employees and 50 contractors.
The mine will further be put under care and maintenance and a small team will be maintained for a short period to complete various activities during this period.
Consolidated Minerals said in a statement: "Despite relentless cost-cutting and marketing efforts to remain competitive, the price for manganese ore is now so low that in the board's view continuing to operate at Woodie Woodie is no longer economically viable.
"The company intends to sell existing ore stockpiles as and when satisfactory prices can be achieved."
Located 400km south-east of Port Hedland, Woodie Woodie mine operates with a fly-in, fly-out workforce from Perth.
Bell Potter Securities marketplace commentator Guiliano Sala Tenna told myExpress: "There are a lot costs concerned to remobilise a site."