The Office of Inspector General (OIG) on Monday released an 80-page report titled "MSHA could not show it made the right decision in approving the roof control plan at Crandall Canyon mine".

Assistant inspector general Elliot Lewis said MSHA was negligent in approving the roof control plan for the Crandall Canyon mine in Utah.

Six miners died in a mine collapse in August last year, and another roof fall 10 days later killed three rescuers attempting to reach the trapped miners.

At the time of the incident Murray Energy was carrying out the "high-risk mining technique" of retreat mining. MSHA had reviewed and approved the mine operator's roof control plans associated with the retreat mining.

The report found that "MSHA did not have a rigorous, transparent review and approval process for roof control plans".

The report also sensationally stated that MSHA could not show it was free from undue influence by the mine operator - Murray Energy. MSHA denied this allegation in the same report, stating it had "expressed concern" that it was "implied MSHA's review process had been subject to undue influence".

Whilst MSHA agreed with the recommendations and said it had already initiated or had plans to initiate the corrective actions made by the report, it did say the use of the word "negligent" was misleading.

“We take exception to the inspector general's use of headline-grabbing language that is unsupported by facts or evidence," MSHA spokesman Matthew Faraci told Australian Associated Press Monday.

The report pointed the finger of blame at both MSHA's field office in Price, Utah, and the agency itself, saying headquarters had exercised little or no oversight.

OIG made several recommendations, including development of rigorous, standard and transparent processes for the approval, implementation and periodic reassessment of roof control plans, including active management oversight; and re-evaluation of the adequacy of existing roof control plans at all underground mines.

It also recommended the clarification of handling non-rescue activities and non-rescue personnel during active rescue operations. During the Crandall Canyon disaster a CNN camera crew was allowed to film underground during rescue activities.

The full report can be found at http://www.oig.dol.gov/CrandallCanyonFinal.pdf