PERSON WAS CHANGING SCREEN DECK AT REFUSE SCREENS ON 2ND FLOOR OF PLANT. PERSON STOOD UP AND STRUCK HIS HEAD ON PIPE THAT WAS LOCATED ABOVE SCREEN, JAMMING HIS NECK. PERSON WENT TO CHIROPRACTO R ON 10-19-00. COMPANY WAS NOT NOTIFIED UNTIL 10-20-00 THAT PERSON HAD RECEIVED TREATMENT.