HELPING MAKE REPAIRS TO ROOF BOLTER, ATTEMPTING TO DISLODGE PIN FROM BOOM SWING JACK, HE WAS STRIKING THE PIN WITH A SLEDGE HAMMER. THE SLEDGE HAMMER GLANCED OFF THE JACK PIN ALLOWING THE HAND LE TO CATCH HIS LEFT RING FINGER BETWEEN THE HANDLE AND THE MACHINE FRAME. THE INJURY WAS A LACERATION AND POSSIBLE AVULSION.