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mine dewater well around 900 mg /1 in 2011. Note that there was one TDS anomaly of 1530 in December <br />2008. Subsequent TDS values obtained in 2011 are within the normal historical average. Historical <br />fluctuations were historically related to the accumulation of water in the North Angle Sump location while the <br />pump was out of order. This water was allowed to equilibrate within old workings and subsided longwall <br />panels. The maximum concentration represents the equilibrium concentration and also provides an indication <br />of the expected post mining TDS concentrations in rubblized zone of underground mine workings. Likewise, <br />this decrease illustrates the effects of flushing upon the TDS concentrations with normal periodic discharge. <br />3.1.3 ALLUVIAL WELLS <br />Water Sediments in the Williams Fork River Alluvium are monitored via three alluvial wells in the general <br />area of the loadout facilities and underground discharge sediment ponds. These include wells AVF -3, AVF -5, <br />and AVF -6. Water quality data for these three wells is provided in Tables 21 through 26. Conductivity data is <br />provided in Figure 21. 2011 data indicates no significant impact on alluvial water quality or levels. <br />Histoncally, groundwater levels in the alluvium have remained fairly regular, with normal seasonal <br />fluctuations, apparently related to changes in river levels. Ground water levels for these wells is plotted in <br />Figure 19. The data indicates no impact on alluvial water levels related to mining. <br />3.2 Surface Water Monitoring <br />3.2.1 Rivers <br />There are two rivers in the vicinity of the mine site. The Yampa River, flows in a southeasterly direction <br />across the mine site. The Yampa River drains most of the northeast corner of Colorado and part of south - <br />central Wyoming. The second river is the Williams Fork, which is a major tributary of the Yampa River. The <br />Williams Fork River joins the Yampa River on the mine property. Monitonng data is collected for the <br />Williams Fork River. <br />The United States Geologic Survey (USGS) had one gage station and one staff gage for collection of <br />Williams Fork River flow data (former site 09249750). The Williams Fork River gage station (WF -2) is near <br />the confluence with the Yampa River, downstream of the Eagle No. 5 Mine discharge. The staff gage (WF -1) <br />is located upstream of the mine discharge points. WF -2 is also monitored concurrent with WF -1. <br />The flow data for WF -2 was historically provided by the USGS, however, monitoring of the Williams Fork <br />stations was discontinued in 2001. Historically, comparisons between up gradient site WF -1, and down <br />gradient site WF -2, have not show any stream depletion impacts from mine dewatering. In October 2006 the <br />State Division of Water Resources (Office of State Engineer) reactivated the site. Data for the former USGS <br />site can be found on their website under station No. WMFKMHCO. A copy of the daily average flow data at <br />Page 6 <br />G.\Environmental \EMPIREWILLIAMS FORK \AHR\2011 \Empire2011AHR.doc <br />