EMPLOYEE HAD BEEN ASSIGNED TO INSTALL A BOLT IN THE BACK PLATE ON THE NO.2 CLEAN COAL SCREEN. AFTER REMOVING THE POWER FROM THE SCREEN HE FAILED TO WAIT UNTIL THE SCREEN HAD STOPPED MOVING PRIOR TO STARTING THE BOLT INSTALLATION PROCESS.WITH THE SCREEN MOVEMENT HIS RIGHT THUMB WAS PINCHED, LACERATING IT. SUTURES WERE REQUIRED.