The company confirmed that two JWR workers had been conducting a routine weekly inspection of a non-producing section of the No. 7 mine at about 2am local time Tuesday when a scheduled check-in point was missed. The missing report led to the dispatch of additional personnel to investigate the inspection area.

“When the miners were located, one was found to be responsive and the other unresponsive,” JWR said.

“The responsive miner has been safely evacuated. During the evacuation, several members of the evacuation team began exhibiting signs of heat stress and were taken to the hospital as a precaution.”

US Mine Safety and Health Administration spokesperson Amy Louviere told ILN that the first two workers were walking in a bleeder at the time of the incident, and that a foreman sent to investigate had found both workers but was forced to retreat due to low oxygen.

“The first miner had no vital signs and the second miner was alive, but breathing with difficulty,” she said, noting that the second miner was transported to a medical center.

While MSHA did not confirm that a 103(k) order had been issued to halt production, JWR did note that the mine was expected to be idle for at least 24 hours.

A federal rescue team was onsite at No. 7 Tuesday afternoon, as were MSHA personnel.

"My deepest sympathies and the sympathies of the entire Walter Energy family go out to the family of the deceased," Walter Energy president and chief executive George Richmond said.

"We will order a full investigation as to the cause of [the] incident."

JWR’s two Alabama operations, No. 4 and No. 7, are considered the deepest vertical shaft mines in North America with overburden ranging between 1500 and 2200 feet. Both extract from the rich Blue Creek seam.

In September 2001, 13 workers died at JWR’s No. 5 operation after an explosion. The mine remained in active production until January 2007.