HUNTINGTON, Utah -- If the six trapped miners are alive, they may be sitting in inky darkness, their headlamps having burned out. Wearing thin work clothes in the 58-degree cold, they could be chilled to the bone if water is seeping into their chamber 150 stories below ground.
How much air they might have is anyone's guess.
On Thursday, more than three days after the thunderous cave-in, a drilling rig on the mountain above the Crandall Canyon mine closed in on the men, trying to bore a hole a mere 2 1/2 inches wide to bring them air and lower a two-way communications device and a tiny camera to check for signs of life.
"We may get no noise," cautioned Bob Murray, part-owner of the mine. "They may be dead."
The drilling rig was erected 1,869 feet above the presumed location of the men and had drilled down 1,530 feet by late morning. The earliest estimated breakthrough time, 6 p.m., passed with no word from mine officials.
But Murray warned that things could go wrong, including equipment breakdowns and the possibility the drill was off target. "We may not come out in the mine where we want to be. We may come out in a solid pillar and have to start all over again," he said.
Rescuers used a second drill to bore a second hole nearly 9 inches wide, but they had reached only 355 feet as of midday. The bigger hole could be used to lower more sophisticated cameras and provisions into the ground.
Simultaneously, rescuers struggled to clear rubble from a horizontal tunnel in an attempt to actually reach the miners and bring them out. But progress was slow at about 300 feet a day, and officials said it could take a week or more to break through to the miners.
The miners were working in an area with an 8-foot ceiling, and the corridors in the mine are typically about 14 feet wide, officials said.
"I'm sure their lights have died by now. I'm sure it's pitch black," said miner Robby Robertson, 27, of Orangeville, Utah, who worked in the mine several years ago. "Imagine the darkest place you've ever been."
Murray, however, said that if the miners survived the cave-in itself, they would probably be spending most of the time in the dark to conserve their headlamp batteries, which are generally good for about 12 hours each.
"As soon as they realized they were trapped, it is very likely they went down to one light and very likely they went into total darkness a lot of the time and only used that light for the purpose of getting to the materials they need to ensure their survival," Murray said. "It wouldn't be bright. It would be like a very, very, large flashlight."
Their other materials typically include a half-gallon of water each in coolers, he said.
Whether air is flowing into the chamber where they were working or is running out is not known. But officials had some reason for optimism, because there was no fire or explosion to consume oxygen or poison the air.
The federal Mine Safety and Health Administration said each miner also should have had at least two emergency air packs, each of which supplies about an hour's worth of oxygen. But whether the air packs were within reach is not known.
Mine operators are also required to keep enough rations for 96 hours, so the Utah miners might have tried to retrieve those, if they were present.
Miners usually wear jeans, sometimes with coveralls on top, and often carry a light denim jacket, Murray said. The steady 58-degree temperature -- which can be comfortable when you're working, less so when you're not -- would not be a problem as long as the men were not wet, the mining veteran said.
He said the area where the miners are believed to be is thought to be "reasonably dry" with possibly some water seepage that they could drink.
Another threat is naturally occurring methane, which is highly explosive. When rocks and coal shift, methane seeps out even faster.
Robertson, the former Crandall miner, said he usually wears thermal underwear, a long-sleeve shirt and overalls, with rubber boots that come up to the knees. "It's kind of chilly" deep in the mines, he said.
Robertson said the men would be helping each other, the older ones being strong for the younger ones.
"If these people are still alive, I'm sure they're all sitting together. I'm sure they're all just trying to comfort each other. I'm sure they know people are trying to get to them," he said. "You're closer to the crew you're on than your own family."
"You try to stick together with one another, which is what we did," said Dennis Hall, one of nine men who survived 77 hours trapped in Pennsylvania's flooded Quecreek Mine in 2002. "We talked to one another and prayed to God a lot."
Trapped miners also typically write letters to their loved ones and put the notes in their lunch pails.
"You feel helpless because you're depending on someone else to get you out of the situation," Hall, 53, of Johnstown, Pa., said Thursday. "When your back's up against the wall and you've used all your efforts to get out, it's a hell of a feeling. And the waiting and wondering is really bad."
Based on his own experience of once being trapped in a mine, Murray said the trapped miners would be confident.
"It's not bad, because they know people are coming after them. If they had enough air they're not worried. We'll get to them before they die. But you've got to understand they may be dead already," he said.
When he was trapped, he said, time went by fast. But, he added, "I could hear them coming after me."
The families of the six miners were praying for their survival, one relative said.
"There are all types of conditions that could be in there for these folks ... some little cavity, some little corner," said Arch Allred, cousin of miner Kerry Allred.
Murray said that keeping the rescuers safe as they tried to work their way toward the trapped miners was paramount.
"Some of these men are willing to take chances to get their brothers out," Murray said. "We can't allow that."
Associated Press writers Jennifer Dobner, Garance Burke and Brock Vergakis in Utah and Vicki Smith in Morgantown, W.Va., contributed to this report.