“[T]he economic return from reserves still available at Tahmoor are not sufficient to warrant the investment required to mine them,” the company said. “A number of options to continue operations were examined, including the proposed Tahmoor South and Tahmoor North projects, but current market conditions do not support these projects.”

Glencore said support services are being put in place to assist its workforce; 350 impacted employees will be gradually reduced over 18 months while development work at Tahmoor is completed.

The metallurgical operation first started production in 1979. It produced 2.1 million metric tons in 2015.