EE SAID HE WAS PUTTING FOOT JACK DOWN ON BOOM OF ROOF BOLTER, WHICH RAISES BOOM ASSEMBLY AND CANOPY, WHEN THE BOOM ASSEMBLY AND CANOPY CAME BACK DOWN 2-3"" HITTING HIM ON HEAD, THE FOOT JACK WA S SETTING ON A ROCK OR CHUNK OF COAL, WHEN THE COAL OR ROCK BUSTED, THE BOOM ASS. AND CANOPY DROPPED.