NATURE OF THE CASE THE KENNECOTT UTAH COPPER DIVISION (HEREINAFTER KENNECOTT IS A SUBSIDIARY OF KENNECOTT CORPORATION, WHICH IS AN OPERATING COMPANY OF STANDARD OIL OF OHIO (SOHIO). KENNECOTT OPERATES AN OPEN PIT COPPER MINE AND LEACHING OPERATION IN SALT LAKE COUNTY, JUST WEST OF SALT LAKE CITY, UTAH. THE MINE PRODUCES APPROXIMATELY 100,000 TONS PER DAY OF COPPER ORE. THIS FACILITY USES SURFACE RUNOFF AND MINE DEWATERING WAT ERS FOR ITS LEACHING PROCESSES. THOSE WATERS WHICH COME INTO CONTACT WITH THE DISTURBED ORE BODY BECOME ACIDIC AND MINERALIZED DUE TO THE NATURAL OXIDATION AND DISSOLUTION OF MINERALS CONTAINED IN THE ORE BODY. HISTORICALLY, THESE WATERS HAVE BEEN RECYCLED AND DISPOSED OF WITHIN THIS FACIL- ITY WITHOUT A DISCHARGE TO SURFACE WATERS. RECORD PRECIPITATION DURING SEPTEMBER 1982, AND HEAVY SNOWFALL DURING THE WINTER OF 1982 - 83, RESULTED IN RUN- OFF THAT PUSHED THIS FACILITY TO THE LIMITS OF ITS HYDROLOGICAL CAPACITY TO PREVENT A DISCHARGE. DURING THIS PERIOD, HOWEVER, KENNECOTT DID NOT APPLY FOR AND NPDES PER MIT. HEAVY PRECIPITATION OCCURRED AGAIN IN SEPTEMBER 1983. AGAIN KENNECOTT HAD TO TAKE EMERGENCY MEASURES TO CONTAIN THE RUNOFF. THIS WAS FOLLOWED BY ANOTHER RECORD SNOWFALL IN THE WINTER OF 1983-84. DURING THIS PERIOD, KENNECOTT OFFICI ALS RECOGNIZED THAT THEY MAY NOT BE ABLE