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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 l09 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 I09 and ll5 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 109 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 [he above described monitoring will verify the <br />accuracy of the calculator. <br />Monitoring for 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 />standard. For this purpose, weekly data from Site 16A 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 rate <br />that would not cause material damage to the downstream Fish Creek AVF. During the winter months, when Site <br />16A is iced over, flow data from USGS station 09239500 will be used for estimating the flow at Site 16A, 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 1~` 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 />cgi/gen_st_pg?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 115. The linear regression relationships and equations are presented below. <br />Flow~6A = (1.008363 * FlowY,,,,P,) + (-3.871291- (2 * (0.4608940))) <br />Flowby = (0.7042560 * FlowY,,,,v,) + (-0.8616838 -(2 * (0.2356389))) <br />Flow~~3 = (1.002034 * Flowv,,,,v,) + (-3.406873- (2 * (0.4574477))) <br />Flowi~s = Flow~~3 + Flowby+ Flowus <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 drill holes, 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 [he mine workings and submitted <br />in the annual hydrologic report. <br />PR 04-06 Exhibit 14 - 4 5/03/04 <br />