HUNTINGTON — Using their bare hands, miners dug through as much as five feet of coal Thursday in a frantic effort to free their buried colleagues.

But it was not enough to save miners Dale Black and Brandon Kimber or mine safety inspector Gary Jensen. Those three men were killed, and six others were injured when a mountain "bump" blew out a 60-foot-long section of coal from the walls, spraying them with rock and debris. The men were part of the rescue effort to reach six miners still trapped inside a collapsed part of the Crandall Canyon Mine.

"These men died as heroes," Utah Gov. Jon Huntsman Jr. said Friday.

The underground rescue attempts have now been halted indefinitely, and an investigation into the deaths is under way.

"We put in the maximum protections we could, and it wasn't enough," said Kevin Stricklin, who is over coal mines for the federal Mine Safety and Health Administration.

Rescuers aren't sure what to do next.

More seismic activity already has been detected in and around the Crandall Canyon Mine, and authorities are unsure when it will be safe to go back underground. But a breakthrough could come today when another hole being drilled through a mountain is expected to break through into a cavern to which the trapped miners may have fled.

"We have suffered a setback," said Rob Moore, vice president of Murray Energy Corp., which owns the mine. "We have incurred an incredible loss, but this team remains focused on the task at hand. That's the rescue of the miners that have been trapped since Aug. 6."

The victims

The rescuers were trying to reach Kerry Allred, Don Erickson, Luis Hernandez, Carlos Payan, Brandon Phillips and Manuel Sanchez, who have been nearly 1,900 feet underground for 13 days.

Miners digging out debris from inside one of the tunnels had just broken through a new section, Stricklin said, when the "bump" hit about 6:30 p.m. Thursday, blowing out from the mine's ribs and burying the nine people in debris.

"The rock props cleared everything in its path," he said. "There were personnel there. They were thrown up against the left rib."

Others raced into the mine to dig out their colleagues. Mine owner Bob Murray was one of them, company officials said Friday. Getting the victims out of the mine took some time.

"I'd say by the time we got everybody outside it was probably about an hour," Stricklin said. "That's counting the travel time that they had with the vehicles to get everybody out."