EMPLOYEE WAS UNLOADING POSTS FROM A SUPPLY CAR INTO A CROSSCUT ALONG THE MAIN NORTH TRACK. HE WAS STANDING ON TOP OF THE CAR WHILE THROWING THE POSTS OFF. HE JAMMED HIS HEAD INTO THE TOP, SPRA INING HIS NECK AND RIGHT SHOULDER AND ARM. NO DAMAGE OCCURRED TO THE MINING EQUIPMENT. THE INJURY DID NOT INVOLVE COMPLIANCE, JOB SKILLS, PROFICIENCY, TRAINING, OR PROTECTIVE ITEMS.