EE WAS HELPING SEPARATE FLANGES ON 100' SECTION OF A PIPE TO INSERT A 3/8"" GASKET USING A 7/8"" X4"" BOLT HEAD BETWEEN THE FLANGES. A RAKE FRONT END LOADER PICKED UP THE PIPE TO CREATE GAP & OPE RATOR MOVED BACK TO CREATE GAP ON OPPOSITE SIDE OF FLANGE. THE MOVEMENT CAUSED GREATER PRESSURE ON BOLT HEAD CAUSING IT TO FLY OUT STRIKING INJURED EMPLOYEE ON RIGHT INDEX FINGER.