Officials held out hope that the men survived Monday's thunderous collapse and that the emergency supplies would help keep them alive while other rescuers tried to punch their way through the rubble in the mine shaft and bring them out.
The crews drilling the two parallel relief holes made encouraging progress Wednesday and could break through by Friday, said Bob Murray, chairman of mine co-owner Murray Energy Corp.
"I consider this to be very, very good news," he said. But it could take at least seven days to actually reach the men and bring them out, Murray said.
The drilling of the relief holes involved boring an extraordinary 1,500 feet straight down, or 150 stories into the earth, through hard sandstone — a task that required precise alignment of the drill and posed the constant risk of a broken bit.
Nothing has been heard from the men since the cave-in, not even the hammering on the ceiling that miners are trained to do in an emergency.
The parallel effort to clear a path inside the blocked mine suffered a major setback Tuesday when seismic shocks wiped out all progress in removing rubble.
Murray offered no estimate on how long the miners could survive — that is, if they are still alive — but backed off a claim Tuesday that they could subsist for perhaps weeks on available air.
"The oxygen depends on the size of the cavity they are in, and I have no idea what size that cavity is," he said Wednesday.
The task illustrated the specific dangers associated with the type of deep mining practiced in the West, where the terrain is rougher than it is in Appalachia and the coal mines are dug far, far deeper into the earth.
Murray's Crandall canyon mine has had 324 safety violations in the past four years, reports CBS News correspondent John Blackstone. But violations can be as minor as a misplaced wrench, and it's not uncommon for mines to have hundreds of citations. Only violations that present an imminent danger of injury or death can get a mine closed down, and Crandall Canyon had none of those.
Over the past few days, the rescuers had to bulldoze 8,000 feet of road across the wilderness and use a helicopter to bring in heavy equipment. They had to balance their drilling rig on a 23-degree mountainside. And then they had to begin boring 1,500 feet straight down into the earth.
The circumstances made the rescue operation "extremely hard, one of the toughest we've had to deal with," said Allyn Davis, who oversees Western mine safety operations for the federal Mine Safety and Health Administration.