EMPLOYEE STATED THAT HE HAD TAKEN THE DRILL STEEL OUT OF THE DRILL POT & STOOD IT ON THE ROOF BOLTER PLATFORM. AFTER INSTALLING THE ROOF BOLT HE WAS REMOVING THE WRENCH AS HE WAS LOWERING THE DRILL POT & AT THE SAME TIME THE ROOF BOLTER MAST CAUGHT THE DRILL STEEL & BENT IT LIKE A BOW PINCHING HIS RT.INDEX FINGER ON TOP OF THE DRILL WRENCH. FRACTURED & LACERATED RT. INDEX FINGER.