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Instream Numeric Standards ( CWQCC 33) <br />The Peabody Sage Creek Mine bond release area discharges surface runoff and spoil leachate into <br />two Segments of the Yampa River in CWQCC's Region 12 of the Yampa River Basin, Segment 13b <br />(Fish Creek and tributaries) and Segment 13e (Grassy Creek and tributaries). <br />Peabody Sage Creek Mine is required to monitor 17 of the parameters in Segment 13b per CWQCC <br />and CDRMS. A review of the statistical summary of the water quality data provided in Peabody <br />Sage Creek Mine's Annual Hydrology Reports and specifically for the past three years was <br />conducted for the mine's NPDES Outfall (NPDES4) and stream sites SSC6, SSC10, SSF11, and <br />SSF13. <br />The total recoverable iron standard, 1.0 mg /1, was exceeded a total of seven times at Sites SSF11 and <br />SSF13 from 2011 to 2013. No exceedances of the iron standard occurred upstream at SSC10, SSB12 <br />or NPDES4; therefore, the exceedances are not likely caused by runoff from the Peabody Sage Creek <br />Mine. The nitrite standard, 0.05 mg /1, was exceeded one time at Site SSF13 with a value of 0.06 <br />mg /1. The nitrite value at Site SSF11, SSC10, SSB12 and NPDES4 were below the 0.05 mg /l value. <br />Therefore, the exceedance at Site SSF13 was not likely caused by runoff of the Peabody Sage Creek <br />Mine. <br />Six out of thirty -six samples from NPDES4 were greater than the chronic selenium standard of 4.6 <br />ug /1, with values between 4.9 and 14 ug /1. The potentially dissolved method is the method that is <br />required for NPDES compliance and the dissolved selenium method is used for assessing stream <br />compliance. No selenium exceedances occurred at any monitored surface sites downstream of <br />NPDES4. <br />Peabody Sage Creek Mine is required to monitor 17 of the parameters in Segment 13e per CWQCC <br />and CDRMS. A review of the statistical summary of the water quality data provided in Peabody <br />Sage Creek Mine's Annual Hydrology Reports and specifically for the past three years was <br />conducted for the mine's NPDES Outfall (NPDES2) and stream sites SSG1, SSG2, and YSG5. <br />The total recoverable iron standard, 1.0 mg /1, was exceeded a total of eleven times at Sites SSG1 <br />(Grassy Creek upstream of the Peabody Sage Creek Mine), SSG2, and YSG5 (both downstream of <br />the Peabody Sage Creek Mine) from 2011 to 2013. No exceedances of total suspended solids <br />associated with high values of iron were noted at the sites; therefore, the Division determines that the <br />exceedances are not likely caused by runoff from the Peabody Sage Creek Mine. <br />Seven out of thirty -seven samples from NPDES2 were greater than the chronic selenium standard of <br />4.6 ug /1, with values between 4.7 and 11 ug /1. The potentially dissolved method is the method that is <br />required for NPDES compliance and the dissolved selenium method is used for assessing stream <br />compliance. One sample at lower Grassy Creek Site YSG5 exceeded the dissolved chronic selenium <br />standard of 4.6 ug /1, with a value of 4.9 ug /1 on April 29, 2013. However, it is noted that a sample <br />collected the same day upstream at NPDES2 displayed a selenium value of 4.5 ug /1 and a sample <br />collected upstream of YSG5 within Scotchman's Gulch before the confluence of Grassy Creek <br />displayed a value of 15.6 ug /1. <br />