EE WAS REMOVING A HOUSING CAP WITH A BREAKER BAR ON THE FLETCHER DRILL WHEN THE CAP LET LOOSE AND EE'S ELBOW STRUCK THE BOLT ON THE ENGINE DOOR. EE FELT FINE AND DID NOT NEED MEDICAL ATTENTION. 4/15/22 EE REPORTED PAIN IN ELBOW AND THAT EE HAS BEEN HAVING TROUBLE SINCE INCIDENT WITH FEELING. SAW THE DR AND WAS ISSUED THERAPY 5/9/22. FILED WITH MSHA 5/11/22.