Company spokesman Gary Broadbent said that longwall mining production has been halted and all underground mining personnel have been withdrawn.

“Once these levels are reduced and stabilized, Foresight will reenter the mine to complete the current longwall move and fully resume normal longwall mining operations at the Deer Run mine,” he said, declining further comment to Coal Age on details and short-term impacts.

The issue is not a new one for the mine; Deer Run was closed from April through July of this year for the same reason after readings revealed elevation on March 26. Additionally, the complex was also idled for a period in 2014 following a fire.

Deer Run produced 5.5 million tons in 2014. Foresight also owns the Pond Creek and Sugar Camp longwall mines and the Shay No. 1 continuous miner operation, all in Illinois.