HUNTINGTON, Utah (CNN) -- Rescue crews in central Utah know exactly where six trapped miners are located, but were forced to turn around late Monday because of "impassable conditions," the mine's operator said.
Crews were instead going to try a method that could take days -- drilling through the top of the mountain. A helicopter-borne drill rig will begin boring down into mountain early Tuesday, said Robert Murray, CEO of Murray Energy, the parent company of the mine's operator.
"We will be on our feet until we get these men out, one way or another," Murray said. If the men survived the collapse, "We just may get them out in two or three days unharmed."
The men were caught in a cave-in at the Crandall Canyon mine before dawn Monday.
Rescuers had hoped to reach the miners by breaking through the seals of an old mine shaft, which could have potentially put them within 100 feet of the miners.
"I'm disappointed to report that our efforts have not been fruitful in this approach to get to the men," Murray said. Crews were driven out by hazardous conditions underground.
There is still hope that crews might be able to breach a second entrance, but if those efforts fail, they will have to rely on the slower, more arduous drilling process, Murray said.
Murray said workers in central Utah were "using every means known to mankind" to reach them.
"We're sparing no expense to bring every mining machine that we have in Utah in here," he said. See the rescue efforts outside the mine »
So far, rescue workers have been unable to establish communication with the miners, who are presumed to be about 1,700 feet away.
More than 200 people are working to retrieve the men. Four rescue teams are already working at the site, and another 12 have been lined up to work in shifts over the next two days, Murray said.
The miners are thought to have been working about four miles from the mine's entrance at the time of the incident, said an official with the U.S. Mining Safety and Health Administration.
Murray said he was confident of the miners' location, but there is still no word on their condition. Watch CNN's Brian Todd give the latest on the search for the six miners »
"They can be in a chamber in there that's 1,000 feet long, or they could be dead," he said.
It could take 48 hours to reach the miners, Murray said, but if they are still alive "there's water and air for far beyond that."
Every miner carries a tank with about an hour's worth of oxygen, officials from Murray Energy said. There are also caches throughout the mine with additional oxygen, they said.
It is unclear whether the collapse was caused by a small earthquake or whether the collapse itself was strong enough to register on seismographs.
The U.S. Geological Survey reported a quake of 3.9 magnitude jolted the region shortly before 3 a.m. (5 a.m. ET), with an epicenter about 16 miles west of Huntington, Utah, close to the mine's location in Emery County. See where the miners are trapped »
Seismographs recorded movement near the area that was "consistent with a mine-type collapse," Walter Arabasz, director of the University of Utah Seismograph Stations, told the Deseret Morning News.
"Now we have to go back and look at more careful analyses to be able to defend with more certainty whether the originating event was an earthquake or whether it was a seismic event caused in a mine environment," he told the Salt Lake City, Utah, newspaper.
It will take about 48 hours to analyze the shake pattern of the seismographs around the area, CNN Meteorologist Chad Meyers said.
A "rock burst" measuring on a seismograph would not be "unheard of" in the region, Davitt McAteer, former head of the U.S. Mining Safety and Health Administration, told CNN.
"It has happened in the past," he said.
The mine -- owned by Genwal Resources Inc. -- reported a cave-in to the Emery County Sheriff's Department about an hour after the seismograph reading was noted.
Inspectors have cited Genwal for 30 violations in 2007, MSHA records show. Recommended fines in the 10 cases where penalties have been leveled so far range from $60 to $524.
Utah Gov. Jon Huntsman Jr. went to the Crandall Canyon Mine to "lend his personal support to the families and mining community during this critical time," his office said.
Huntsman told reporters the families of the trapped men were at an "undisclosed location" near Huntington, about 140 miles south of Salt Lake City.
"I am confident, based upon what I heard from Mr. Murray, that every expense is being made in order to do this right -- no stone left unturned," he said. "They're bringing in the professionals and all the equipment they need, hopefully to make this a successful outcome."
Mine rescue teams from the Rocky Mountain Power Co. are on standby if they are needed, spokesman Steve Eskelsen said. In addition, the power company has offered to loan out its heavy equipment, he said. E-mail to a friend
CNN's Peter Dykstra and Brian Todd contributed to this report.
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