EE SET THREE PCS TIMBE IN CHUTE. THEN FIRED COAL SET IN GANGWAY FOR ABOUT 15 MINUTES. THEN WENT UP CHUTE TO PUSH COAL DOWN CHUT. WHEN A ROCK ABOUT 3' X 2' FELL AT TOP OF CHUTE ONTO SHEET IRON AND CAME DOWN TO BOTTOM OF CHUTE AND HIT EE ON LEGS. SUFFERED TWO BROKEN LEGS.