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• below 750 umhos/cm, then the evaluation would be made as to the rate at which effluent <br />can be discharged into Fish Creek and maintain compliance with the sulfate standard on <br />Trout Creek. The winter flow estimates will be as described below for Sites 69 and 1003. <br />Only Site I09 discharging -Between June and February, when only Site 109 is <br />discharging and the discharge is entering Foidel Creek, weekly monitoring will be <br />performed at Site 69 for flow rate and conductivity, and at Site 301 for conductivity. <br />This data will be used for calculating the maximum rate of discharge from Site 109. <br />Both 109 and IIS discharging -Flow and electrical conductivity will be obtained at <br />Sites 69, 1005, 109 and 115, and the data will be entered into the Mine Discharge <br />Calculator for determining the maximum discharge rates from Sites ]09 and 115. The <br />results may be that TCC can only discharge from one, both, or neither of the sites. The <br />calculator will determine those rates and the above described monitoring will verify the <br />accuracy of the calculator. <br />Monitoring jot Fish Creek's 1500 umhos/cm material damage standard The "Contingent" monitoring in Table <br />A also includes monitoring aimed at preventing exceedances of Fish Creek's 1500 umhos/cm material damage <br />standazd. For this purpose, weekly data from Site 16 and weekly EC from Site 115 will be entered in the "Fish <br />Creek Calculator" (see Table E49-25). The Fish Creek Calculator determines Site 115's maximum discharge <br />rate that would not cause material damage to the downstream Fish Creek AVF. During the winter months, when <br />Site 16 is iced over, flow data from USGS station 09239500 will be used for estimating the flow at Site 16, and <br />this value will be used in the "Fish Creek Calculator", as shown below. The EC and sulfate data will be <br />forwarded to the Division on a quarterly basis for the period of 1st quarter, 2000 through 4th quarter 2001. The <br />• data will be submitted within 45 days of the end of the respective quarter. <br />Estimating wintertime surface flows from correlations with Yampa River USGS site. During the winter, when <br />ice conditions prevent accurate measurement of surface water flow rates at monitoring sites, they will be <br />estimated using a relationship with the USGS station on the Yampa River below Steamboat Springs (09239500). <br />This data is available on an instantaneous basis year-round on the Internet (http//nwis-colo.cr.usgs.gov/rt- <br />cgUgen_st~g?station=09239500). Since there is insufficient data from Site 1005 to develop a relationship, a <br />relationship with Site 1003 (Fish Creek above Trout Creek) was developed. This flow is added to the flow from <br />Sites 69 and 1 ] 5. The linear regression relationships and equations are presented below. <br />FIow16 = (1.008363 * Flovvyamp~ + (-3.871291- (2 * (0.4608940))) <br />FIow69 = (0.7042560 " Flowyamp~ + (-0.8616838 -(2 * (0.2356389))) <br />FIow1003 = (1.002034 * Flowyamp~ + (-3.406873- (2 * (0.4574477))) <br />Flow1005 = FIow1003 +FIow69+ FIow115 <br />Mine Inflow Monitoring <br />Mine inflow monitoring will be performed on an annual basis, typically in the spring. The survey will consist of <br />onsite measurement of water inflow where it occurs in the mine using bucket and stopwatch, portable flumes or <br />estimates of flow in areas where direct measurement is not possible. The source of the inflow such as faults, <br />fractures, abandoned dril-hoies, etc., will be identified. Field measurements of temperature, pH and specific <br />conductance will be selectively performed. The data will be plotted on a map of the mine workings and <br />submitted in the annual hydrologic report. <br />TR OI-38 Exhibit 14 - 4 8/?8/01 <br />