Laserfiche WebLink
is CDPS Outfall 003, a.k.a. site SD. Under TC, monitoring of these sites remains the same as in the active <br />mining monitoring plan. <br />Summaries of [he available water quality data for the mine discharge sites are presented in Tables 7 through <br />10. The plot of dissolved solids presented in Figure 5 shows that the average dissolved solids in the Eagle <br />No. 5 Mine discharge water have increased slightly from about 800 mg/l in 1982 and 1983 to between 870 <br />mg/I and 920 mg/1 in 2004. The average dissolved solids concentration for the 7 North Angle site was 1100 <br />mgA in 2003 (Note: [his site did not flow in 2004), which is a return to values common in 1994 and 1995. <br />Water levels for the 7 North Angle well are monitored on a quarterly basis. This data is presented in Table <br />9A. <br />3.1.3 ALLWIAL WELLS <br />Water quality in the Williams Fork River Alluvium is monitored via alluvial well AVF-5, which is located <br />adjacent to the underground discharge sediment ponds area (See Figure 2). Undet TC, AVF-5 is measured for <br />water level and field parameters on an annual basis (between July 20th and August 30th) concurrent with the <br />Williams Fork surface water sampling (site WF-1). No water quality analyses are required for AVF-5 under <br />TC. <br />Historically, groundwater levels in the alluvium have retrained fairly regular, with normal seasonal <br />fluctuations, apparently related to changes in river levels. POR groundwater levels in AVF-5 are plotted in <br />Figure 6. The data indicates no impact on alluvial water levels related to mining. <br />Field parameter data for AVF-5 for 2004 is presented in Table 11. POR water quality data is provided in <br />Table 12. A plot of field electric conductivity versus time is presented in Figure 7. There has been no <br />conclusive evidence of seasonal variation of water quality in the alluvium. AVF-5 was within historic levels <br />in 2004. <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. Monitoring data is collected for the <br />Williams Fork River. <br />The United States Geologic Survey (USGS) had one gaging station and one staff gage for collection of <br />• Williams Fork River flow data. The Williams Fork River gaging station (WF-2) is near the confluence with <br />the Yampa River, downstream of the Eagle No. 5 Mine discharge. The staff gage (WF-1) is located upstream <br />4 <br />I:\Env\Em pireW H R\2004\Teut\Empire2004AH R.doc <br />