HE WAS LETTING THE ATRS DOWN TO ADVANCE TO ANOTHER ROW OF BOLTS WHEN A KETTLE BOTTOM BROKE LOOSE FROMT HE TIP HITTING THE ATRS BREAKING THE KETTLE BOTTOM INTO 2 PIECES ONE PIECE HIT THE RIB AN D SLID DOWN THE RIB PINNING HIS LEG AGAINST THE ROOF BOLTER AND BREAKING IT IN 2 PLACES.