The wind-down in activities at the Abel underground mine also contributed to the downturn.
The company produced a total 3.18 million tonnes saleable coal for the quarter. Sales volumes for the reporting period were 3.23Mt, down 11% on the year prior.
In New South Wales, Moolarben open cut production was up 8% on the previous year, with its continued ramp up in production, overburden extraction, fleet controls and throughput efficiencies enabling positive improvements for the period.
Construction of the Moolarben Stage Two underground mine continued in accordance with project targets, with first development coal scheduled for extraction during the second quarter reporting period.
Challenging geological conditions at the Stratford Duralie open cut affected extraction rates for the period, down 34% year-on-year, with the mine set to increase its run rates in the second half of the year once through the current mining area.
Scheduled longwall moves at the Ashton underground offset initial strong production gains achieved at the beginning of the year, with production up 41% on the year prior. The mine subsequently introducing two continuous miners to enable earlier relocation of the longwall into the ULLD seam.