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MINREC, INC. ANNUAL HYDROLOGIC REPORT PAGE 5 Discharge Monitoring Reports (DMRs) DMRs are submitted quarterly to the Colorado Department of Public Health and Environment with copies to the Division of Minerals and Geology and are included herein by reference. ANTICIPATED IMPACT Discharge from outfall 001 may slightly impact the quality of water in North Thompson Creek. The mine water discharge has a low iron content and an acceptable pH, however its conductivity is moderately high. The following table presents the impact outtall 001 would have on the conductivity of North Thompson Creek at varying discharge rates. Antici ated Im act -North Thom son Creek NTC - 2004 Outfall 001 Flow m Conductivity Outfa11001 NTC Flow cfs Conductivity NTC Conductivity Combined % Increase Decrease 15 1970 5 494 504 2.0 17.2 1970 5 494 505 2.2 20 1970 5 494 507 2.6 25 1970 5 494 510 3.2 30 1970 5 494 513 3.8 35 1970 5 494 517 4.7 40 1970 5 494 520 5.3 45 1970 5 494 523 5.9 Conductivity -umhos/cm -Average for 2004 The average flow during 2004 of 17.2 gpm with a conductivity of 1970 (2004 Ave.) discharging into a receiving stream with a 5 cfs flow and a conductivity of 494 (pre-permit mean) would increase the conductivity of the receiving stream to about 505 umhos/cm, an increase of about 2.3% which is considered insignificant. The Colorado Department of Public Health and Environment has regulations regarding saline discharges into the Colorado River. A discharge of one ton of salt per day is considered a no-salt discharge by the Department of Health. A flow rate of 100 gpm from with a TDS concentration of 1500 mg/I would yield a salt concentration of 0.9 tons per day, slightly below the one ton per day of salt discharge limitation. The average flow rate at Outfall 001 was 17.2 gpm with a TDS concentration of 1399 mg/I during 2004 which equates to a discharge of 0.14 tons of salt per day.