SUPERVISOR WAS ATTEMPTING TO GET TO STUCK DRILL STEELS APART. WHEN THEY CAME APART THE STEEL THAT WAS IN THE ROOF FELL OUT STRIKING HIS FINGER. CAUSE OF THIS INJURY WAS SAFETY AWARENESS. COMPL IANCE W/RULES/REGS WAS NOT A FACTOR, MINER ATTITUDE A FACTOR, SAFETY EQUIPMENT WAS BEING WORN, MINING EQUIP./SYSTEMS NOT A FACTOR.