2014-06-06_REPORT - C1981044 (7)

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3.1.2 Mine Water Discharge The No. 5 Mine well discharge is Colorado Department of Public Health and Environment's (CDPHE's) Colorado Discharge Permit System (CDPS, a.k.a. NPDES) discharge point 003. The 7 North Angle discharge is CDPS discharge point 024. Discharge Monitoring Reports (DMRs) for the first through fourth quarters of 2013 are provided as an attachment to this report. The No. 5 Mine discharge water quality (Figure 18) indicates dissolved solids concentrations consistent with historic values (typically under 1150 mg/L). The high dissolved solids concentration for the 7 North Angle in 2013 was 1100 mg/L. The average dissolved solids concentration for 7 North Angle were around 1150 mg/L in 2000, which was a return to values common in 1994 and 1995. Historically, this trend was related to the accumulation of water in the North Angle Sump location while the pump was out of order. This water was allowed to equilibrate within old workings and subsided longwall panels. The maximum concentration represents the equilibrium concentration and also provides an indication of the expected post mining TDS concentrations in rubbleized zone of underground mine workings. Likewise, this decrease illustrates the effects of flushing upon the TDS concentrations with normal periodic discharge. 3.1.3 ALLUVIAL WELLS Water Sediments in the Williams Fork River Alluvium are monitored via three alluvial wells in the general area of the loadout facilities and underground discharge sediment ponds. These include wells AVF -3, AVF -5, and AVF -6. Water quality data for these three wells is provided in Tables 21 through 26. Conductivity data is provided in Figure 21.2013 data indicates no significant impact on alluvial water quality or levels. Historically, groundwater levels in the alluvium have remained fairly regular, with normal seasonal fluctuations, apparently related to changes in river levels. Ground water levels for these wells is plotted in Figure 19. The data indicates no impact on alluvial water levels related to mining. 3.2 Surface Water Monitoring 3.2.1 Rivers There are two rivers in the vicinity of the mine site. The Yampa River, flows in a southeasterly direction across the mine site. The Yampa River drains most of the northeast corner of Colorado and part of south - central Wyoming. The second river is the Williams Fork, which is a major tributary of the Yampa River. The Williams Fork River joins the Yampa River on the mine property. Monitoring data is collected for the Williams Fork River. The United States Geologic Survey (USGS) had one gaging station and one staff gage for collection of Page 6 1:\ Env \Empire\AHR\2013 \Test \Empire2013 AHR.doc