EE & HIS PARTNER WERE DRILLING A RAISE UP ROUND ABOUT 12 FEET AWAY FROM EACH OTHER. WHILE COLLERING A HOLE A ROCK SLID DOWN THE DRILL STEEL CAUSING HIS PARTNER TO LET GO OF THE JACKLEG. WITH N O CONTROL THE LEG EXTENDED FULL LENGHT & FELL, STRIKING THE OTHER EMPLOYEE ON THE CHEEK. THEY WERE DRILLING WITH 6' STEEL.