A PIECE OF DRAW ROCK FELL ONTO THE HEAD AND ONTOTHE CONVEYOR CHAIN MEASURING 8""-20""W, X40""L X8"" THICK. THE ROCK WAS BEING CONVEYED ALONG THE BOOM & APPARENTLY BECAME FOULED & CAME OUT STRIKING THE SHUTTLE CAR & FALLING ONTO THE MINER OPERATIORS LEFT ANKLE CAUSING A 1"" LACERATION