"They felt the percussion and heard the noise," Hatfield said. "We believe they probably encountered heavy smoke and the ventilation system was obstructed. They then did what skilled miners do."

McCloy and the 11 others were found at the deepest point of the mine, about 2 1/2 miles from the entrance, behind a fibrous plastic cloth stretched across an area about 20 feet wide to keep out deadly carbon monoxide gas, Hatfield said.

Each of the miners in the barricaded area also had a breathing apparatus that purifies the air and had been able to use it, according to mine officials.

Late Wednesday, about 200 people gathered outside the Sago Baptist Church for a candlelight vigil to remember the miners.

Hatfield refused to say whether the miners wrote notes to their families.

McCloy was in intensive care at West Virginia University's Ruby Memorial Hospital in Morgantown, undergoing dialysis because of damage to his kidneys from dehydration. Dr. Lawrence Roberts said McCloy squeezed his wife's hand Wednesday and was communicating with other movements.

The miners had been trapped 260 feet down since Monday morning in the Sago Mine, about 100 miles northeast of Charleston.

David Dye, who heads the Mine Safety and Health Administration, said the investigation into the disaster will include "how emergency information was relayed about the trapped miners' conditions."