EE WALKED TO #7 ENTRY TO RETRIEVE A WRENCH HE HAD DROPPED. AS HE WALKED INTO #7 ENTRY A PIECE OFDRAW ROCK 27""/2""/3 TO 5 INCHES FELL STRIKING HIMON THE HEAD. NOTE: EE HAD BROKEN HIS NECK WHILE WORKING AT A PREVIOUS COMPANY. THIS BLOW TO THE HEAD IRRITATED A PREEXISTING CONDITION.