“After working closely with regulatory agencies, operations were permitted to resume at the beginning of October,” the company said.

Following Pinnacle’s closure from weeks of sporadic carbon monoxide level spikes, the company intentionally flooded the affected portion of the operation while working on a remediation plan with the US Mine Safety and Health Administration.

Cliffs also issued force majeure notices to its affected customers, initially estimating a July restart. Officials did not comment Tuesday on the status of shipments.

The Pinnacle complex in Pineville, made up of the Pinnacle and Green Ridge mines and the Pinnacle preparation plant, operated the only longwall plow system operating in the US. Its annual capacity is 4 million tons of low to medium-volatile metallurgical coal.