COEUR d'ALENE - Federal mine safety regulators say a Nov. 17 accident at Lucky Friday Mine that killed a miner occurred because management failed to provide proper personal protective equipment.

The federal Mine Safety and Health Administration on Thursday released its report from the investigation of 26-year-old miner Brandon L. Gray's death. Gray worked for Cementation USA Inc., which was contracted by Hecla Mining Co. to do work on a shaft inside the Mullan-area silver mine.

Mike Nadon, president of Cementation USA, said, "We saw a lot of errors in the report."

He said they are working on a response.

Gray was injured when he and a coworker were working on top of a pile of broken rock - called muck - and the pile gave way beneath them. As it gave way, they became engulfed in the material.

They were underground in the mine to help excavate a bin for broken rock storage.

The coworker, Jason Figueroa, was partially buried but was freed, treated at a hospital, and then released the same day.

Gray was completely engulfed in the material. He was freed and hospitalized, but died Nov. 19.

"The accident occurred due to management's failure to ensure miners were provided with the proper personal protective equipment when required to remove blocked material in the bin," MSHA's report concluded. Nadon said the material was not blocked or plugged.

The report said the two men were standing on plugged material wearing harnesses attached to what are called "self-retracting lifelines."

The lifelines used were designed for an unobstructed fall path, the report said.

When the material suddenly gave way and flowed underneath them and the miners fell, their fall wasn't rapid enough to cause the self-retracting lifelines to lock before the men became engulfed, the report said.

"Additionally, the miners didn't receive the proper training to safely perform the task of removing the blocked material from the bin," the report said. They also lacked training for working in confined spaces, it said.

Gray's cause of death was attributed to suffocation and mechanical compression.

A Nov. 18 press release by Hecla said both men were "believed to be wearing all required personal protection equipment, including fall protection."

Amy Louviere, a spokeswoman for MSHA, said penalties haven't yet been assessed.

Jim Sabala, a senior vice president for Hecla, said the company is reviewing the report and would take any safety recommendations under advisement.

As for the self-retracting lifelines used by Gray and Figueroa, the manufacturer's user-instruction manual contains a section entitled, "Locking Speed," which stated, "Situations which don't allow for an unobstructed fall path should be avoided."

Locking of the device would be affected if users are working on "slowly shifting materials, such as sand or grain," the manual said, according to MSHA's report.

The manual said working in confined or cramped spaces might not allow sufficient speed for locking.

Nadon said the lifelines used that day by Gray and Figueroa were appropriate for "normal situations."

He said the muck the two miners were working on turned out to have some "unusual characteristics."

Nadon criticized MSHA for taking months to complete the investigation and file a report.

"It struggled to find blame," Nadon said.

Gray had three years and five months of mining experience.