To get back underground, MSHA said it will begin assembling a team of experts today to look at what can be done. Federal authorities thought they had taken steps to protect rescuers working underground, placing beams and chainlink fence inside the tunnels.

"Obviously, it was not adequate," assistant U.S. Labor Secretary Richard Stickler told reporters Friday.

It is unknown when mine officials will be able to resume underground rescue efforts. It depends on the seismic conditions.

"We don't want to close the door and say no one can ever go in underground," Stricklin said. "But we need to suspend it until we're confident that we won't have another situation like we did."

Investigations

Huntsman said the rescue effort has gone from a tragedy to a catastrophe, suggesting that rescue efforts should cease until workers' safety could be guaranteed.

"Let us ensure that we have no more injuries," he said. "We have suffered enough as a state."

In an interview with the Deseret Morning News on Friday, Huntsman said he plans to put together a panel for the state to conduct its own investigation into the mine disaster to determine if Utah should have more control over mine safety. It is also likely that congressional hearings will be held.

"I just hope people don't try to politicize this here," said Sen. Orrin Hatch, R-Utah, leaving a meeting with MSHA officials. "Unfortunately, we have people back in Washington who do that."

Late Friday afternoon, President Bush phoned Huntsman, the second time they have spoken since the Aug. 6 collapse.

"President Bush called Gov. Huntsman to express his sympathies to the family members affected by (Thursday's) mine rescue accident and also to those families still waiting to hear about their loved ones still trapped in the mine," Huntsman spokeswoman Jami Palmer said.

The University of Utah Seismograph Stations recorded two more instances of seismic activity near the Crandall Canyon Mine on Friday. The first one registered 1.2 on the Richter scale at 1:12 a.m. The second one hit at 6:12 a.m., registering 0.9 in magnitude.

Thursday's deadly bump was 1.6 in magnitude and extremely shallow in the ground. The seismic wave forms are consistent with downward motion, just like the original 3.9 magnitude collapse on Aug. 6. A natural earthquake does not have the downward motion signature, scientists say.

According to the the U., 24 seismic "after-events" had been recorded within about two miles of the mine as of Friday morning. Twelve of those were within two days of the original collapse.