Chris Adkins, a vice president of mine owner Massey Energy, said crews needed more time to drill additional ventilation holes to clear poisonous, volatile gases from the Upper Big Branch Mine and make the underground environment safe for rescuers, The Charleston Gazette reported.
"I still believe in God, and I believe" Adkins said of the possibility of finding the four unaccounted-for miners alive. "I'm not going to give up."
Earlier Thursday, rescue teams for a second time were recalled from the mine after they got within 1,000 feet of a rescue chamber where they hope the miners would be. Repeated air samples indicated the air quality could lead to another explosion.
"We've had a setback," Kevin Stricklin, coal administrator for the U.S. Mine Safety and Health Administration, said during a morning briefing. "There is so much gas built up in the area that it's taking us a while to ventilate."
West Virginia Gov. Joe Manchin said the situation was "the worst scenario" for rescuers.
Officials have said Monday's blast likely was caused by an explosion of methane gas, possibly fed by coal dust.
President Barack Obama directed federal mine safety officials to provide their initial assessment into what caused the explosion next week, the White House said Thursday.
Obama will meet with Labor Secretary Hilda Solis and Mine Safety and Health Administrator Joe Main, expecting them to report on their initial assessment of the deadly explosion's cause, the safety record at the Massey Energy Upper Branch mine and steps the federal government should take to improve safety enforcement and prevent future tragedies, the White House said in a statement.
United Mine Workers of America International President Cecil Roberts said the safety record at the non-union Upper Big Branch in particular and of Massey Energy overall was troubling and "demands a tough investigation."
Roberts said a UMW Health and Safety Department review of coal mine fatalities since 2000 showed 20 people had been killed at mines operated by Massey, its subsidiaries or subcontractors before the Upper Big Branch explosion.
"Our hearts and prayers remain with the families of those who lost loved ones at this mine," Roberts said in a statement posted on the UMW Web site. "(However), we cannot ignore the very troubling realities of what happened in that mine in the days and weeks leading up to the disaster. Nor can we ignore the grim statistics that are associated with Massey and the mines under its control."
The explosion is the worst U.S. mining disaster since 1984, when 27 people died in a Utah mine.