The longwall subsequently encountered geological challenges, affecting total production for the 12 months to December 2014.

Austar run-of-mine coal production was 1.88 million tonnes for the period, with saleable coal production of 1.51Mt.

On April 15 last year, two employees died in an underground incident at Austar and mining stopped while a recovery operation took place.

An investigation into the cause of the incident by the NSW Mine Safety Office is continuing and Austar does not have approval to restart development work.

Development crews were redeployed to the Donaldson and Ashton underground mines in April.