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MINREC, INC. ANNUAL HYDROLOGIC REPORT PAGE 5 <br />Discharge Monitoring Reports (DMRs) <br />DMRs are submitted quarterly to the Colorado Department of Public Health and <br />Environment with copies to the Division of Minerals and Geology and are included herein <br />by reference. <br />ANTICIPATED IMPACT <br />Discharge from outfall 001 may slightly impact the quality of water in North Thompson <br />Creek. The mine water discharge has a low iron content and an acceptable pH, however <br />its conductivity is moderately high. The following table presents the impact outfall 001 <br />would have on the conductivity of North Thompson Creek at varying discharge rates. <br />Antici ated Im act -North Thom son Creek NTC - 2003 <br />Outfall 001 <br />Flow m Conductivity <br />Outfa11001 NTC Flow <br />cfs Conductivity <br />NTC Conductivity <br />Combined % Increase <br />Decrease <br />15 1944 5 494 504 1.9 <br />17.2 1944 5 494 505 2.2 <br />20 1944 5 494 507 2.6 <br />25 1944 5 494 510 3.2 <br />30 1944 5 494 513 3.9 <br />35 1944 5 494 516 4.5 <br />40 1944 5 494 519 5.1 <br /> <br />Conductivity -umhos/cm -Average for 2003 <br />The average flow during 2003 of 17.2 gpm with a conductivity of 1944 (2003 Ave.) <br />discharging into a receiving stream with a 5 cfs flow and a conductivity of 494 (pre-permit <br />mean) would increase the conductivity of the receiving stream to about 505 umhos/cm, an <br />increase of about 2.2% which is considered insignificant. <br />The Colorado Department of Public Health and Environment has regulations regarding <br />saline discharges into the Colorado River. A discharge of one ton of salt per day is <br />considered a no-salt discharge by the Department of Health. A flow rate of 100 gpm from <br />with a TDS concentration of 1500 mg/I would yield a salt concentration of 0.9 tons per day, <br />slightly below the one ton per day of salt discharge limitation. The average flow rate at <br />Outfall 001 was 17.2 gpm with a TDS concentration of 1346 mg/I during 2003 which <br />equates to a discharge of 0.14 tons of salt per day. <br />The entire mine site has been reclaimed and seeded. Good plant growth has occurred <br />since 1988. During 1992 a study was pertormed at the mine site that demonstrates <br />untreated drainage from the reclaimed area contributes fewer suspended solids than <br />