EE WAS ROOF BOLTING ON UNIT 1. AS HE WAS INSTALLING ROOF BOLT A PIECE OF LOOSE ROCK FELL, STRIKING HIM ON HARD HAT, RT SHOULER, RT ARM. EE STARTED MISSING TIME JUNE 4, 03 & IS UNDER THE DR'S C ARE AT THIS TIME. THIS INCIDENT HAS BEEN UNDER INVESTIGATION PENDING THE DR'S DIAGNOSIS & REPORTS. THE REPORTS WERE RECEIVED JUNE 10, 2003 CONCERNING THE EE'S CONDITION.