Coronado said coal sales volumes at Curragh were down 500,000 short tons as a result of reduced production due to the temporary suspension of mining activities at the mine during January and February after a safety incident in early January that led to the death of an employee of one of its contractors.

Lower sales volumes were exacerbated by lower average realised metallurgical coal pricing, which was reduced by US$35.1/Mt sold from the $137.1/Mt sold as of March 31 2019 due to softer market conditions and falling index prices.

 "Higher demurrage costs in the Australian operations were also incurred in the quarter as a result of longer vessel wait times at the port due to the disruptions in production," Coronado said.

Freight expenses totalled $42.4 million for the March quarter, an increase of $5.1 million from the $37.3 million for the previous corresponding period.

The company's freight expenses primarily relate to the Australian operations and relate to costs associated with take-or-pay commitments for rail and port providers and demurrage costs.