November 2004, a BLM inspector noted that pillars of coal, which were holding up the mine's roof, were failing [...missed in 2005 due diligence??]

Agency Inspectors Knew of Mine Problems | JENNIFER TALHELM | October 2, 2007 05:05 PM EST

WASHINGTON — At least three years before the deadly August accident at Utah's Crandall Canyon Mine, Bureau of Land Management inspectors noted serious structural problems that they feared could cause the mine's roof to collapse, Congress was told Tuesday.

Yet the government's mine safety office didn't know of the bureau's concerns until after the accident, Kevin Stricklin, a coal mine safety administrator for the department, testified during a Senate hearing.

The Labor Department oversees the mine safety office and approved the Crandall Canyon mining plan. The Bureau of Land Management, which oversees how much coal is mined from public land, is governed by the Interior Department, a separate agency.
...
Lawmakers have said they are skeptical that the government did everything it could to prevent the accident. They also have questioned why the Bureau of Land Management noticed the problems at Crandall Canyon _ but not the mine safety department.

Documents released by the committee showed that in November 2004, a BLM inspector noted that pillars of coal, which were holding up the mine's roof, were failing.

The inspector, Stephen Falk, said that further mining by pulling out the pillars would be "untenable" and "wishful thinking" in hopes of extending the mine's life.

"Mining any of the coal in the pillars will result in hazardous mining conditions such as pillar bursts and roof falls," Falk wrote. ...