BHP said metallurgical coal production for the September quarter of 11 million tonnes was underpinned by an improvement in trucking hours and utilisation of latent wash-plant capacity.

This was offset by lower production at the Broadmeadow longwall top coal caving mine due to difficult roof conditions.

BHP said the Caval Ridge Southern Circuit project was progressing according to plan, with production expected to ramp-up early in the 2019 financial year.

Turning to energy coal, production for the September 2017 quarter decreased 2% to 7 Mt. 

New South Wales Energy Coal production increased 7% as it benefitted from improved stripping performance and additional bypass coal. 

This was offset by a 15% decrease in volumes at Cerrejon in Colombia, which was constrained following the impact of extreme wet weather at the end of June 2017.

Energy coal guidance for the 2018 financial year is unchanged at approximately 29Mt to 30Mt, while metallurgical coal guidance is unchanged at between 44Mt and 46Mt.