The coal giant downgraded its production guidance from 16.4-18.4 million tons for the quarter to around 15Mt.

Consol put the lowered production expectations down to several roof falls on mainline belts, delays in the resumption of longwall production due to equipment moves at different mines, more safety inspections and reduced equipment availability.

Consol expects its fourth-quarter coal outlook to be back up at 17.8-19.8Mt.

Higher production costs had an impact on Consol’s bottom line in the second quarter, which saw the company profits drop by more than a third.

For the June quarter, the Pennsylvania producer reported earnings of $US101 million versus $153.1 million during the same period last year. Last year's second quarter included $59 million in profit from asset sales.

Consol operates 20 bituminous coal mining operations in the US and is one of the largest coal miners in the Appalachian region.