Those killed and the six others injured Thursday night were part of a perilous operation to find the missing miners, who were caught in a similar failure 12 days ago. They were burrowing through a rubble-choked tunnel when they were caught in seismic "bump," which can cause the walls of a mine tunnel to implode, at about 6:35 p.m., said Dirk Fillpot, a spokesperson for the federal Mine Safety and Health Administration (MSHA).
One man died at Utah Valley Regional Medical Center in Provo, said hospital spokesman Janet Frank. Another died at Castleview Hospital in Price; it was unclear when and where the third man was confirmed dead. One of the dead, MSHA confirmed today, was an employee of that agency.
The surviving rescue workers' injuries ranged from head trauma to broken bones to bumps and bruises. By this morning three of them had been treated and released from Castleview Hospital, while another man was in stable condition in the hospital's intensive care unit with a back injury. Castleview CEO Jeff Manley said he could be released in two to three days.
Others were being treated at UVRMC and University Hospital in Salt Lake City, spokespeople said. Their identities, and those of the men who died, were not immediately available -- but the victim at UVRMC was reported in fair condition with a broken leg and head injuries, while the man at University Hospital was in fair condition today, a nursing supervisor said.
Among those injured were Crandall Canyon employees and two MSHA managers who were involved in the rescue effort in the mine, which has been unstable for months. The fate of the six missing miners is unknown, despite unceasing efforts to locate their whereabouts and to reach them through the enormous mine's main entrance.
The deadly setback had a grim Gov. Jon M. Huntsman demanding today that MSHA and mine owner Robert Murray not resume underground rescue efforts until "certain guarantees" of worker safety can be offered.
"It has gone from a tragedy to a catastrophe," he told CNN. "We shouldn't allow another person in the underground mine until we can ensure their safety. . . . No one wants the lives of these heroes to be lost in vain."
Murray had confirmed earlier this week that some miners -- reportedly as many as a dozen -- had asked to be moved to a different part of the rescue operation because they were afraid for their safety.
Meanwhile, the University of Utah Seismograph Stations in Salt Lake City confirmed today that the latest cave-in had registered on their sensors as a 1.6 magnitude event at 6:39 p.m. Thursday. Spokesman Lee Siegel said seismologists characterize the reading as "very, very shallow," about one-tenth of a mile beneath the surface.
The nature of the seismic waves measured from the event provide strong indications that it was a "mining-induced settling of the mountain" that follows the original 3.9-magnitude cave-in on Aug. 6.
"It seems like this mountain is settling or collapsing in slow motion," Siegel said, noting that since the initial event nearly two weeks ago there have been 19 seismic spikes, or "bumps" at Crandall Canyon, seven of them this week -- two on Thursday, one Wednesday, two on Tuesday and two on Monday.
Siegel noted that the addition of five seismic sensors in the area of the mine last week was helping scientists zero in more accurately on ground disturbances at the Emery County mine.
The tragic turn registered a much higher magnitude on the hearts of the closeknit mining community.
"It is a devastating blow to what was already a tragic situation," said Joe Piccolo, mayor of Price, one of many communities in the coal-rich region. Piccolo's own father died in a coal mine disaster half a century ago.
Throughout the rescue effort, both Murray and MSHA officials have reported numerous mine bumps, some of which had forced evacuation of crews working underground. Indeed, Murray had earlier described the seismic activity as "relentless.
"The mountain is still moving and we cannot endanger the rescue workers as we drive towards these trapped miners, for whom I take total responsibility," he said Thursday, prior to the latest cave-in.
Owned by Ohio-based Murray Energy Corp., Crandall Canyon Mine lies 1,800 feet under a mountain near Huntington. It consists of a horizontal complex dug some four miles into the mountainside; by its very nature, the mine is subject to intense pressure on the pillars, wire mesh and roof bolts intended to protect the tunnels and those working in them.
Prior to the collapse Thursday, Murray reported that underground crews had only been able to clear 26 feet of the rescue tunnel in nearly a day's work, leaving them 1,600 feet short of a cavity where missing miners Don Erickson, Luis Alonso Hernandez, Brandon Phillips, Juan Carlos Payan, Kerry Allred and Manuel Sanchez were believed trapped.
Work continued today on an above-ground effort to drill a new 8 5/8-inch borehole down to the cavity. Three previous boreholes, through which microphones and video cameras have been dropped, have revealed no sign of the missing miners; only some bags, mining vehicles and rubble.
Air monitors lowered into the cavities did show that in some cases, the oxygen content of the air yielded faint glimmer of hopes that the men survived the initial catastrophic collapse and barricaded themselves away from lethal, oxygen-deficient air released into the working section when the mine's walls collapsed.
Monitors lowered through the last of the three boreholes measured oxygen concentrations of roughly 16 percent. Typical air contains about 21 percent. The first boreholes drilled closer to the working section had only a deadly 7 percent oxygen level.
At 16 percent oxygen, MSHA director Richard Stickler said, "your heart rate will be elevated slightly. . . . It's similar to jogging or walking fast. . . . You can survive at 16 percent."
With the determination that breathable air was present, rescue organizers began drilling a fourth borehole into the mine around noon Thursday. It was aimed on a diagonal at a spot in the same tunnel as the third borehole, but about 650 feet closer to the area where the miners were working.
Stickler said that tunnel was targeted because mine maps show that it would be the most logical spot for miners fleeing toxic air to erect tarplike barricades to protect their breathable supplies from contamination.
It also is in the proximity of "noise" detected Wednesday morning by two of six geophones, sensitive seismic listening devices placed in a large diameter circle on the mountain above the mine.
Stickler clarified that the listening devices, which recorded vibrations every 1.5 seconds for five minutes after the third drill hole pierced the tunnel Wednesday morning, did not mean that the the "noise" originated in the mine.
"What we were picking up, we can't tell you that it was in the mine. . . . We have no idea if it's at the surface, or somewhere in the rock strata, or in the coal seam or even in the rock strata below the coal seam, " he said. "But we felt it was significant enough that we could not discount it and that was the reason for [selecting] the location of the borehole."
Murray also said that a brattice curtain seen underground - the tarplike material that would be used in a barricade - actually had been photographed by a camera lowered down the second borehole, far from the bleeder tunnel where rescue organizers thought the miners might build a refuge.
Murray said the fourth borehole would be 1,586 feet deep and likely would reach its destination late Friday or early Saturday.
--- Patty Henetz, Jeremiah Stettler, Olga Munoz, Jason Bergreen, Bob Mims and Donald W. Meyers contributed to this report.