Employee was installing roof bolts in the face of the No. 2 entry. After adding the finishing piece of steel in place he placed his hand on the drill steel until it was fully inserted back into the hole, at which time the piece of rock measuring 15-16 in. wide, 78 in. long & 2-2 1/2 in. thick fell next to the steel striking him in the area of the 4th-5th fingers of the left hand.