EMPLOYEE WAS USING PRY BAR TO DISLODGE ROCK CAUGHT BETWEEN ROLLER & CONVEYOR BELT. BELT CAUGHT AHOLD OF BAR & THREW IT BACK TOWARDS EMPLOYEE. EMPLOYEE WAS STRUCK ON RIGHT SIDE OF FACE AND HIS HEAD HIT A LADDER. EMPLOYEE HAS A BRUSIED JAW & A LUMP ON LEFT SIDE OF HEAD. TAKEN TO CLINIC WHERE HE WAS EXAMINED, HAD X-RAY OF JAW. NO BROKEN BONES. HE IS OFF WORK 12/11 DUE TO SHIFT CHANGE.