In its last quarterly report, Whitehaven said it had difficulty recruiting underground miners and contractors to fully utilise its four mining units.

This led to the mine falling 509 metres short of planned progress to December.

If production continues at this rate, longwall production will occur in mid- to late April.

“An additional contractor, SBD-Delta, is operating with experienced people to supplement development at Narrabri while Narrabri employees are trained for longwall operation,” the report said.

Construction of the second stage of facilities and the delivery of the longwall and other equipment is on time and on budget.

An ongoing review of stage two costs indicates there will be no change to the estimated capital cost of $300 million.

Meanwhile, the company’s four open-cut mines in the region experienced minor disruption from December’s wet weather.

Reduced explosives deliveries following the shutdown of the Orica plant in Newcastle also interrupted planned mining and affected coal production.

This led to the open-cut mines producing at an annual rate of about four million tonnes per annum of saleable coal in the December quarter, which was significantly below planned levels.