AN OVERSIZED ROCK BECAME LODGED IN THE FEEDER OF THE PRIMARY CRUSHER. EMPLOYEE WAS STANDING ON THE CATWALK NEXT TO THE FEEDER ATTEMPTING TO DISLODGE THE ROCK WITH A METAL BAR. ANOTHER ROCK SHIFTED & SLID INTO THE BAR MASHING THE EE'S HAND BETWEEN THE BAR & THE HANDRAIL OF THE CATWALK. EE SUSTAINED A FRACTURED THUMB & CONTINUES TO WORK ON RESTRICTED DUTY.