EMPLOYEE HIT A BUMP IN THE HAUL ROAD EXITING THE PIT RAMP, WHICH HAD BEEN RECENTLY BACK DRUG FOLLOWING A RAIN EVENT. HE BOUNCED UP & HIT HIS HEAD ON THE ROOF OF THE CAB AND HIT HIS KNEE ON TH E WINDOW CRANK. HE DIDN'T REPORT THE ACCIDENT TO HIS SUPERVISOR UNTIL 8/25/00; HE STATED THAT EVERY DAY AFTER THE ACCIDENT, THE JARRING OF THE TRUCK MADE HIS BACK HURT MORE, & HE REPORTED THE