Air readings from a fourth hole drilled more than 1,500 feet into the mountainside found insufficient oxygen to support life, said Rob Moore, vice president of Murray Energy Corp., co-owner of the Crandall Canyon Mine. "It's likely these miners may not be found," Moore said, expressing a marked shift in tone in his mine officials' assessments of the chances the men would be rescued, hopes they had maintained even after three rescuers were killed and six more hurt Thursday in another "bump" inside the mountain.