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IV. Geology - Rules 2,04.5 and 2.04.6 A description of the geology is contained in the permit application on Pages 2.04-6 and 2.04-7. A detailed discussion of the "geologic anomaly" encountered in early 1988 is contained in this section. The operation is in compliance with the requirements of this section. V. Hydrologic Balance: Surf 7. 2.05 Information on the quantity and quality of surface water in the mine area can be found in the application beginning on page 7_.04-32; in Exhibits 6, 9, and 10; and on Map 7. The major drainages which could be impacted by this mining operation are the Purgatoire River, the Ciruela Canyon drainage, the Santistevan Canyon drainage, and the Apache Canyon drainage. The Purgatoire River is a perennial stream; Santistevan Canyon also contains a perennial stream. Apache Canyon and Ciruela Canyon, however, contain either intermittent or ephemeral streams. The monitoring requirements, past and present, for these surface drainages is covered on Page 2.05-35, Table 22, and in Exhibit 10 of the application. Water quality in the Purgatoire River and Ciruela Canyon will be affected by mine discharge water. The Purgatoire River will receive this discharge both from pond 5 and by means of Ciruela Canyon. Pond 5 is a new facility approved to treat the bulk of Golden Eagle mine water before discharge to the Purgatoire River. The Ciruela Canyon drainage is an ephemeral or intermittent tributary of the Purgatoire River that flows primarily in response to snowmelt or rainfall. It receives mine water discharge from Pond 2B, the last of a series of adjacent settling ponds. Both discharges from Ponds 5 and 2B will be monitored regularly in accordance with the applicant's revised NPDES permit. The sediment control system has been reviewed by the Division. Designs for the sediment control system are found on pages 2.05-9 through 2.05-16 and in Exhibit 6 of the renewal application. Surface runoff from the disturbed area is contained by sediment ponds 3 and 4. locations of these ponds appear on Map 11, Sediment and Surface Water Control Plan. These ponds are capable of containing the runoff generated by a 10-year, 24-hour storm event and are designed to contain 0.1 acre-feet of sediment per acre of disturbed area. The ponds are both equipped with principal spillways and emergency spillways capable of passing the peak flow from a 25-year, 24-hour storm event. The principal spillways are gated, but the gate will be opened a calculated amount to allow for automatic dewatering with a detention time of 24-hours. A series of ditches route disturbed drainage water to the ponds and undisturbed drainage around the disturbed area. These ditches are capable of handling the peak flow from a 10-year, 24-hour storm event. -8-