EMPLOYEE HAD FINISHED INSTALLING HIS ROOF BOLTS AND WAS MOVING BACK TO THE SIDE TRAM LEVERS WHEN A RIB ROLLED OFF KNOCKING HIM AGAINST THE SIDE OF THE DRILL. THE IMPACT CAUSED HIM TO TWIST HIS BODY AS HE FELL TO THE GROUND. ON 2/22 HE SAW AMEDICAL SPECIALIST WHO PUT HIM ON RESTRICTIONS.