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This years TDS value at Wadge coal well YW30 was 7030 mg /l. The PHC <br />predicted value for this well is 2570 mg /l. Since 2009, TDS values have <br />been fluctuating up and down, making it difficult to determine an <br />accurate trend. <br />Surface Water <br />A summary of surface water sites is provided in Table 9. Stream <br />monitoring occurs on Sage Creek at Sites YSSF3 and YSS2, and on Grassy <br />Creek at Sites YSGFS and YSGS. These surface water sites are monitored <br />biannually for flow and field parameters (pH, temperature, and <br />electrical conductivity [EC)). All five NPDES sites are monitored <br />monthly for NPDES parameters and field parameters. Samples obtained at <br />the stream sites are analyzed for one of the new surface water parameter <br />lists during spring runoff and summer baseflow. Spring sites are <br />monitored in the spring season. The current surface water and spring <br />monitoring program is presented in Table 15 -9 of the Yoast Mine PAP. <br />All surface water data collected during this reporting period are <br />provided in Appendix D. Data for each site begins with a flow hydrograph <br />of all historic data (plus an annual hydrograph for NPDES sites), <br />followed by a listing of individual water quality and quantity data for <br />the current water year, and followed by remarks if present. This is <br />followed by a TDS regression plot using the LOWESS method (see the <br />Ground Water Quality section). <br />A statistical report representing baseline (i.e., premining) data for <br />each site downstream of mining (when available) is provided in Appendix <br />D1 of the 2010 AHR. On this statistics report, "censored data" refers to <br />analytical values that were below the detection limit, which were <br />censored from the min /max /mean calculations. The time frame for baseline <br />conditions is listed under "conditions specified" at the bottom of each <br />page. <br />7 <br />