HUNTINGTON — The three miners killed and six who were injured were a little more than 800 feet along the rescue operation path into the Crandall Canyon Mine when walls of coal caved in on them Thursday.

Officials with the federal Mine Safety and Health Administration said a 1.6-magnitude pressure-shifting mountain "bump" at 6:35 p.m. Thursday caused the collapse during the effort to reach six miners trapped nearly 1,900 feet underground.

A 60-foot-long wall of coal blew out with such force that it piled coal and debris nearly 5 feet high, burying the rescuers, said Kevin Stricklin, coal safety director for MSHA.

Stricklin said it took another team of rescuers an hour to retrieve the buried men, digging with their hands if they had to. The collapse has resulted in the indefinite suspension of underground operations at the mine, with the looming question of when, if ever, they will resume.

The collapse was the result of materials shifting inside the mine.

"It hit with tremendous force," said assistant U.S. Labor Secretary Richard Strickler, who is over MSHA.

"It knocked out all of the ground support we had in place," he said.

Two of the dead have been identified by family and friends as Brandon Kimber and Dale Black, Crandall Canyon Mine employees.

MSHA on Friday confirmed the identity of one of its employees killed in Thursday's accident. MSHA spokeswoman Amy Louviere said Gary L. Jensen, 53, who worked out of MSHA's Price field office, was among the three rescuers killed.

Louviere said Jensen was assigned to the Price office, which is part of the district office based in Denver, as a member of the special investigations group. The group is assigned to investigate mine accidents for criminal intent on the part of mine owners.

Jensen began his career with MSHA in 2001 as a coal mine inspector at the Colorado office. In July 2003, he was transferred to Price as a roof control specialist.

In a statement released this afternoon, UtahAmerican Energy said five of the six injured also worked for UtahAmerican, while the other worked for MSHA.

Speaking to reporters today, Utah Gov. Jon Huntsman Jr. said the rescue effort has gone from a tragedy to a catastrophe.

"These men died as heroes," he said. "I can think of no better way to express our love for a fellow human being than to risk your life for someone else's as we saw last night."

Huntsman, federal authorities and mine company officials met with the families of the six trapped miners this morning, discussing options in the aftermath of this latest collapse.