REPAIRMAN WAS WORKING WITH TWO OTHER REPAIRMEN TO SPLICE THE FEED CONVEYOR TO THE TERTIARY SCREENS DURING A SCHEDULED SHUTDOWN. WHILE SEARCHING FOR AN AVAILABLE 110VAC RECEPTACLE TO PLUG HIS T OOLS INTO, EE LOST HIS BALANCE AND FELL INTO THE TAIL PULLEY GUARD CAUSING CONTUSIONS TO HIS RIGHT HIP AND BACK. RETURNED TO REGULAR DUTIES ON 2-23-02 FOLLOWING ONE REQUIRED DAY OF REST.