EE'S FEET GOT STUCK IN MUD AND TRYING TO GET OUT OF THE MUD, HE TWISTED AND FELT PAIN IN HIS BACK AND HIP. CAUSE OF INJURY WAS OVEREXERTION. COMPLIANCE WITH RULES/REGS NOT A FACTOR. DID NOT IN VOLVE MINING EQUIP OR MINING SYSTEMS, MINER PROFIENCY MAY BE A FACTOR, PROTECTIVE ITEMS NOT A FACTOR.