EE WAS TRAMMING THE R-50 HAUL TRUCK DOWN THE S. RAMP LOADED WHEN HIS BRAKES FAILED. HE DROVE TO THE NEXT BENCH THEN INTO THE BERM. THE TRUCK HITIT AT A PERPENDICULAR ANGLE CAUSING THE TRUCK TO JUMP THE BERM & STRIKE ANOTHER WHICH STOPPED THE TRUCK. THE OPERATOR WAS WEARING HIS SEAT BELT THUS KEEPING HIM IN THE TRUCK. X-RAYS SHOWED TWO FRACTURED RIBS. HE WAS RELEASED FOR LIGHT DUTY.