THIS IS AN ADMINISTRATIVE ORDER AGAINST THE ASARCO INCORPORATED, NEWMONT MINING CORPORATION, RES-ASARCO JOINT VENTURE, AND RESURRECTION MINING COMPANY UNDER SECTION 106 OF CERCLA TO PERFORM THE REMEDIAL DESIGN/REMEDIAL ACTION AT THE YAK TUNNEL OPERABLE UNIT. THE RESPONDENTS ARE EACH OWNERS OR OPERATORS OR PAST OWNERS OR OPERATORS OF THE YAK TUNNEL AND/OR RELATED FACILITIES. THE YAK TUNNEL, WHICH IS LOCATED IN THE CALIFORNIA GULCH NATIONAL PRIORITY SITE, LEADVILLE, CO, A TUNNEL CONNECTING NUMEROUS UNDERGROUND MINE WORKINGS, DIS- CHARGES WATER CONTAINING VARIOUS METALS, INCLUDING CADMIUM, COPPER, LEAD, AND ZINC. ON MARCH 29, 1988, EPA SIGNED A ROD FOR THE YAK TUNNEL. THE ROD WAS MODIFIED BY EPA ON MARCH 23, 1989.