Coronado CEO Gerry Spindler said Curragh's continued operational improvements had delivered a sizeable increase in run-of-mine, saleable production and sales volumes in the June quarter compared to the March quarter.

"Run-of-mine production benefitted from the improved performance of overburden removal and a 2% increase in dragline efficiency compared to the March 2019 quarter," he said.

"Our Australian operations delivered 3.3Mt in sales representing an increase of 8.9% on the prior quarter.

"This pleasing result was underpinned by significantly improved rail availability that allowed us to recover delayed sales from the March 2019 quarter."

Metallurgical coal as a proportion of saleable production was 83.8%, up 4.9% compared to the prior quarter.

Export sales of 77.8% were up 3.2% compared to the prior quarter

The company's realised metallurgical coal price of US$137.8 per tonne was up 0.5% on the prior quarter.