Yancoal Australia has placed its Donaldson coal operation near the Port of Newcastle on care and maintenance after ceasing mining activities at the Abel underground mine and the starting of new feasibility studies.
In March, the company said that operations would be suspended due to ongoing market challenges worldwide.
Yancoal's decision to put the operation on care and maintenance comes as the company considers future development of new underground working areas.
The company has redeployed the majority of Donaldson employees to the neighbouring Austar and Ashton underground operations.
Yancoal said in a statement: "Care and maintenance includes the ongoing rehabilitation of the Donaldson site in accordance with existing approvals, as well as the management of the site both above and below ground as Yancoal works to consider all options for the potential further mining of the Abel underground."
Donaldson's underground Abel mine produces thermal and semi-soft coking coal for blending, exporting through the Port of Newcastle.
The mine produced 1.81 million tonnes of ROM coal and 1.34 million tonnes of saleable coal in 2015.
The operation consists of Abel and Tasman underground mines, as well as Donaldson open-cut mine.