Price, Utah (AP) Federal regulators say the operator of a collapsed Utah mine violated safety protocols by cutting coal pillars that should have been left standing to prevent cave-ins.

A federal report says a subsidiary of Ohio-based Murray Energy Corp. undermined other pillars by excavating coal from tunnel floors.

The first details of the Mine Safety and Health Administration report came Thursday from a summary issued to reporters and interviews with family members and their lawyer.

The August 6th, 2007 collapse trapped six miners whose bodies haven't been recovered. Three others were killed during a rescue attempt.

MSHA said Murray Energy misled regulators about the dangers and violated its approved mining plan. The company says it is preparing a response.