EE WAS USING A HAMMER IN AN ATTEMPT TO REMOVE A WORN CUTTING BIT FROM THE CONTINUOUS MINER RIPPER HEAD. UPON STRIKING THE BIT A PIECE OF THE HAMMER HEAD BROKE AND PENETRATED THE SKIN, IMBEDDIN G IN HIS RIGHT THUMB. EE DID NOT SEEK MEDICAL TREATMENT FOR THIS INJURY UNTIL 4-18-02. THE METAL WAS SURGICALLY REMOVED.