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<br />MINREC, INC. ANNUAL HYDROLOGIC REPORT PAGE 4 <br />1 <br /> <br /> <br />1 <br /> <br /> <br />1 <br />OUTFACE 001 -QUALITY <br />YEAR FLOW H COND TDS IRON <br />_ 1989-- _--X6.5-- __--~_9-- ---3598_ ---2512_ ___1,51_ <br />_ 1990__ ___17_0__ ____8.1 __ ___3157 _ ___2129 _ ___1,16_ <br />_ 1991-- ---?~-~ -- ----8-~ -- ---2890 - ---2018 - ---~-~$- <br />1992 19.3 8_0 2722 1805 0.72 <br />------ -- <br />-- <br />- <br />°5 cF3 -_-- <br />-- --- <br />- _-- <br />_ --- <br />1993 22.4 7.9 2643 1738 0.54 <br />--------- ----------- <br />DS cF3 ---------- ---------- ---------- --------- <br />1994 21.2 7.6 2627 1710 0.52 <br />--------- ---------- <br />.D7 cF5 ---------- ---------- ---------- <br />1995 <br />---- 32.5 <br />---- 7.8 <br />-- 2435 1663 0.17 <br />----- --- <br />--- <br />.oScFs ----- <br />--- ---------- ---------- --------- <br />1996 36.8 7.8 2082 1441 0.15 <br />--------- ---------- <br />Iz <FS ---------- ---------- ---------- --------- <br />1997 52.0 7.6 2083 1424 0.20 <br />SA~r <br />(TONS/gyp/ <br />.z3y I <br />,GIs <br />_3z5 <br />_3/9 <br />.yY% <br />' The units for the figures in the above table are; flow (gpm), pH (standard units); <br />conductivity (umhos/cm); total dissolved solids (mg/I) and iron (mg/I). Iron was measured <br />as total recoverable until April 1994 when the Colorado Department of Public Health and <br />' Environment changed the discharge permit to require iron to be measured as potentially <br />dissolved. <br />' WET TESTS <br />The discharge permit requires quarterly, two species chronic Whole Effluent Toxicity <br />' (WET) tests on effluent from outfall 001. A two species chronic bioassay was performed <br />four times during the year using C. dubia and Pimephales promelas, fathead minnow. <br />' Results found that the effluent demonstrated no toxicity to C. dubia or fathead minnow <br />survival in any concentration less than or equal to the instream waste concentration (IWC). <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 quite high. A 52 gpm flow with a conductivity of 2083 discharging into <br />a receiving stream with a 5 cfs flow and a conductivity of 494 (pre-permit mean) would <br />' increase the conductivity of the receiving stream to about 530 umhos/cm, an increase of <br />less than 10% which is considered insignificant. <br /> <br />1 <br />