Tragedy At Utah Coal Mine

Authorities say a disastrous cave-in Thursday night at the Crandall Canyon coal mine near Huntington, Utah, killed three rescue workers and injured at least six others who were trying to tunnel through rubble to reach six trapped miners.

CBS News correspondent Susan Roberts says the deaths of the three rescue workers have been confirmed by state and mine officials.

Mining officials are considering whether to suspend the rescue effort, which was already halted twice before due to dangerous shifting of earth in the mine.

It was a shocking setback to the effort to find miners who have been confined at least 1,500 feet below ground since an August 6th collapse at the mine. It's unknown if the six are alive or dead.

The pace of the rescue had picked up Thursday, but crews working underground nonetheless estimated that they were at least a week away from reaching the spot where the stranded miners might be.

Six of the rescue workers injured Thursday night were taken to Castleview Hospital in Price, Utah. One died there, one was airlifted to a Salt Lake City hospital, one was released and three were being treated, said Jeff Manley, the hospital's chief executive.

The second dead worker passed away at Utah Valley Regional Medical Center in Provo, Utah, according to hospital spokeswoman Janet Frank. Another worker there is in serious condition with head trauma but is alert, Frank said.

The third death was confirmed by Rich Kulczewski, spokesman for the U.S. Department of Labor, but more details were not immediately available.

Utah Gov. Jon Huntsman was flying by helicopter to the hospital in Price and planned to meet with mine safety officials overnight to discuss the future of the rescue operation. Three people were confirmed dead and the six original miners have not been heard from since the Aug. 6 collapse.

"Whatever happens from now on, all I ask on behalf of all Utahns is that we have no more injuries," Huntsman said in a prepared statement. "We have been through enough. We must ensure from this day forward every lesson learned here will go towards improving safety in mines - not only in Utah but throughout the United States."

Authorities said the cave-in was caused by a mountain bump, which commonly refers to pressure inside the mine that shoots coal from the walls with great force. Seismologists say such an event caused the Aug. 6 cave-in that trapped six men inside the central Utah mine.

Thursday's bump at 6:39 p.m. MDT showed up as a magnitude 1.6 seismic event at University of Utah seismograph stations in Salt Lake City, said university spokesman Lee Siegel.

Family members of miners, many in tears, gathered at the mine's front entrance looking for news.

A mine employee, Donnie Leonard, said he was outside the mine when he heard a manager "yelling about a cave-in."

A woman who answered the phone at the mine said mine co-owner Bob Murray was not available for comment.

It was not immediately clear where the injured people were working or what they were doing when they were hurt. Crews have been drilling holes from the top of the mountain to try to find the miners while others were tunneling through a debris-filled entry to the mine.

Underground, the miners had advanced to only 826 feet in nine days. Mining officials said conditions in the mine were treacherous, and they were frequently forced to halt digging because of seismic activity. A day after the initial collapse, the rescuers were pushed back 300 feet when a bump shook the mountain and filled the tunnel with rubble.

Before Thursday's collapse, workers still had about 1,200 feet to go to reach the area where they believe the trapped men had been working.

The digging had been set back Wednesday night, when a coal excavating machine was half buried by rubble by seismic shaking. Another mountain bump interrupted work briefly Thursday morning.

"The seismic activity underground has just been relentless. The mountain is still alive, the mountain is still moving and we cannot endanger the rescue workers as we drive toward these trapped miners," Murray, chief of Murray Energy Corp., the co-owner and operator of the Crandall Canyon mine, said earlier Thursday.

Murray has become more reticent to predict when the excavation would be complete. At the current rate, it figures to take several more days.

On top the mountain, rescuers were drilling a fourth hole, aiming for a spot where they had detected mysterious vibrations in the mountain. That drilling was believed to be continuing after the latest accident, but the mine was evacuated and officials haven't decided whether to suspend the rescue effort, Kulczewski said.

Officials said Thursday that the latest of three holes previously drilled reached an intact chamber with potentially breathable air.

Video images were obscured by water running down that bore hole, but officials said they could see beyond it to an undamaged chamber in the rear of the mine. It yielded no sign the miners had been there.

Murray said it would take at least two days for the latest drill to reach its target, in an area where a seismic listening device detected a "noise" or vibration in 1.5-second increments and lasting for five minutes.

Officials say it's impossible to know what caused the vibrations and on Thursday clarified the limits of the technology.

The device, called a geophone, can pinpoint the direction of the source of the disturbance, but it can't tell whether it came from within the mine, the layers of rock above the mine or from the mountain's surface, said Richard Stickler, chief of the federal Mine Safety and Health Administration.

The "noise," a term he used a day before, wasn't anything officials could hear, Stickler said. "Really, it's not sounds but vibrations."

Officials stressed that the motion picked up by the geophones could be unrelated to the mine, even as they drilled the new hole in an effort to uncover the source of it.

Together with the discovery of an intact chamber and breathable oxygen levels, the baffling vibrations offered only a glimmer of hope for rescuing the miners, but Murray seized on the developments Thursday.

"The air is there, the water is there - everything is there to sustain them indefinitely until we get to them," he said.

Officials said results of air quality samples taken from the intact chamber, accessed by the third deep borehole, showed oxygen levels of roughly 15 to 16 percent.

Normal oxygen levels are 21 percent, and readings in other parts of the mine taken since the Aug. 6 collapse have registered levels as low as 7 percent.

At 15 percent oxygen, a person would experience effects such as elevated heart and breathing rates, Stickler said.

Video images from the same shaft showed an undamaged section complete with a ventilation curtain that divides intake air from exhaust air. Behind the curtain, in theory, the men might have found refuge and breathable air when the mine collapsed 10 days ago.

Also Thursday, Murray corrected comments he made late Wednesday that a camera that detected the curtain had been lowered through the third borehole, made at the rear of the mine. The curtain was actually observed by a camera sent down a borehole drilled earlier into an area where the trapped men had been working, he said.

Nothing had been detected or heard since the five-minute period Wednesday, Stickler said Thursday.