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Clean Water Act Effluent Limitations (40 CFR Part 434) <br />Monitoring data for the past three years indicate that the Seneca II Mine has not caused exceedances <br />of either limitation identified in 40 CFR Part 434 that is applicable to reclamation areas on coal mines <br />(settleable solids of 0.5 ml /l and pH of 6.0 to 9.0). Seneca II Mine only notes settleable solids values <br />that are at or above the detection limit of 0.4 ml /1; no exceedances of 0.4 ml /l were noted. <br />Impacts to Alluvial Valley Floors (AVFs) <br />The Seneca II Mine conducted an impact proj ection analysis as noted in Tab 7, Section VII.A. Lc in <br />C- 1980 -005. The analysis concluded that total dissolved solids (TDS) increase in the Fish Creek <br />stream flow as a result of surface water discharges from NPDES8 on the order of 76 mg /l for the <br />months of June and July. The projection equates to TDS concentrations in the Fish Creek streamflow <br />ranging from 497 to 607 mg /1. <br />Based on a demonstration provided in Tab 7, Section VII.B. Lc, crops grown in the area of alluvium <br />can tolerate TDS concentrations in excess of 2,000 mg/l. Predicted TDS concentrations of Fish <br />Creek streamflow of only 497 to 607 mg /l will not result in water quality changes that significantly <br />and adversely affect the composition, diversity or production of the vegetation dependent on <br />subirrigation. Water quality data for June and July at Sites SSF11 and SSF13 from 2003 to 2013 <br />show that the maximum increase of TDS between the sites was 50 mg /l in June (a 74 mg /l increase <br />was predicted) and 70 mg /l in July (a 74 mg /l increase was predicted). TDS increases on Fish Creek <br />due to the Seneca 11 Mine are not causing significant negative impact to potential crops in the area. <br />Findings on Protection of Hydrolo2ic Balance <br />According to Rule 3.03.2(2), the Division must conduct an inspection and an evaluation to determine <br />whether pollution of surface or subsurface water is occurring, the probability of future occurrence of <br />such pollution, and the estimated cost of abating such pollution. <br />Based on the review of the water monitoring data for the Seneca II Mine, the observed hydrological <br />impacts are consistent with those predicted in the probable hydrologic consequences (PHC) section of <br />the permit, C- 1980 -005. Although the 4.6 ug/l selenium standard was exceeded at NPDES8, this <br />standard is a "Report" only based on the requirements of CO- 0000221. The receiving stream <br />standard for selenium has not been exceeded at any of the downstream monitoring sties. <br />Water pollution is not occurring at the Seneca 11 Mine and, based on a review of the monitoring data <br />and on- the - ground observations, there is no potential for future water pollution. Water quality at the <br />alluvial Ground Water Point of Compliance well is within the prescribed limits. Based on the <br />foregoing observations regarding hydrologic impacts, the Division finds SCC has minimized <br />disturbance of the hydrologic balance in the bond release area and adjacent areas, and prevented <br />material damage outside the permit area. <br />On Tuesday, November 25, 2014, the Division met with Erin Scott and Kathy Rosow of CDPHE's <br />Water Quality Control Division (WQCD). This meeting occured as a part of the interagency <br />