Whitehaven Coal lifted production by 66 per cent in in the June quarter due to the continued ramp up of Maules Creek mine.
The miner produced 4.75 million tonnes of saleable coal during the June quarter, up from 2.87 million tonnes a year ago.
Total coal sales for the year were 13.987Mt, a 29 per cent increase over the previous year following the inclusion of sales from Maules Creek for the first time.
1.4 million tonnes of coal was produced at Maules Creek, which has only been open for around six months.
Whitehaven said the annualised production rate of 6 Mt was achieved at Maules Creek during the quarter, with the next expansion phase to an annualised rate of 8.5Mt planned to occur later in CY2015 as more mining equipment is introduced into the mine.
Narrabri mine also saw strong production in the quarter, with ROM and saleable coal production at 2.671Mt and 2.346Mt respectively, 57 per cent and 69 per cent higher than the previous corresponding quarter.
Whitehaven said coal prices have continued to fall in 2015 as a result of lower demand in the seaborne market.
Whitehaven said prices for its metallurgical coal averaged $US75.90 in the June quarter, down from $US87.15 in the preceding quarter.
Whitehaven achieved an average price for all its export thermal coal sales of $US60.72/t for the quarter, down from $US65.37 in the three months to March.
Managing director Paul Flynn says metallurgical coal prices are set to fall further in the next quarter, but expects thermal coal prices to remain stable.