EMPLOYEE WAS ATTEMPTING TO OPEN A DOOR AND EXIT THE BOTTOM FLOOR ELECTRICAL ROOM OF THE SCALPING TOWER AT THE PREP PLANT. LOOSE COAL HAD FALLEN ON THE CATWALK OUTSIDE THE DOOR AND BLOCKED THE DOOR FROM OPENING. EMPLOYEE KICKED THE DOOR PARTIALLY OPEN. THE DOOR BOUNCED BACK AND HIT HIS FINGER. DID NOT INVOLVE ANY DAMAGE TO THE MINING OPERATION OR EQUIPMENT.