EMPLOYEE WAS ROLLING A PIECE OF VENTILATION CURTAIN BESIDE THE BUCKET OF THE SCOOP. HE SAID HE HEARD THE RIB BEHIND HIM BREAK AND ATTEMPTED TO JUMP CLEAR, AS HE DID THE RIB ROLLED AND CAUGHT THE CURTAIN, HE STILL HAD A HEAD OF THE CURTAIN WHEN HE JUMPED, THE RIB CAUGHT THE CURTAIN A NAIL WAS IN THE CURTAIN, IT WAS DRAWN INTO AND TORE SKIN ON LEFT INDEX FINGER.