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MINREC, INC. ANNUAL HYDROLOGY REPORT PAGE 4 WET TESTS The discharge permit requires chronic Whole Effluent Toxicity (WET) tests to be performed on effluent from outfall 001. A two species chronic WET test using C. dubia and Pimephales promelas, fathead minnow, is required semi-annually during the second and fourth quarters. A single species chronic WET test using C. dubia is required semi- annuallyduring the first and third quarters. A two species chronic bioassay was performed two times (2"d and 4th quarters) during the year using C. dubia and Pimephales ropy melas, fathead minnow. A single species chronic bioassay was performed two times (15 and 3`d quarters) during the year using C. dubia. Results found the effluent demonstrated no toxicity to C. dubia orfathead minnow survival in any concentration less than or equal to the instream waste concentration (IWC). 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 outfall 001 would have on the conductivity of North Thompson Creek at varying discharge rates. Antici ated Im act -North Thom son Creek NTC - 2005 Outfall 001 Flow m Conductivity Outfa11001 NTC Flow cfs Conductivity NTC Conductivity Combined % Increase Decrease 10 1929 5 494 500 1.2 14.9 1929 5 494 503 1.8 15 1929 5 494 504 2.0 20 1929 5 494 507 2.6 25 1929 5 494 510 3.2 30 1929 5 494 513 3.8 35 1929 5 494 516 4.5 40 1929 5 494 519 5.1 Conductivity - umhos/cm -Average for 2005