THIS IS AN ADMINISTRATIVE ORDER ISSUED TO ATLANTIC RICHFIELD COMPANY FOR A PHASED REMEDIAL INVESTIGATIONI/FEASIBILITY STUDY ( RI/FS ). THE ORDER REQUIRES RESPONDENT TO SUBMIT A SITE MANAGEMENT PLAN, CONDUCT A PRELIMINARY RI/FS, PROPOSE AND IMPLEMENT EARLY RESPONSE ACTIONS TO ADDRESS KNOWN SOURCES OF ACID MINE DRAINAGE, AND CONDUCT LONG-TERM RI/FS.