Company officials said in a filing with the Australian Securities Exchange (ASX) that the Hunter Valley operation is moving to care and maintenance status because of “ongoing global market challenges as the operation considers the future development of new underground working areas.”

Donaldson’s coal, which totaled about 1.34 million metric tons (mt) in 2015, is primarily exported to Asian customers via the Port of Newcastle. Only underground mining remains active at the mine; its open-pit portion was mined out about three years ago.

Yancoal acquired the operation in 2012 following the company’s merger with Glouster Coal.