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impacts to the Trout Creek Sandstone. The water quality data for this Trout Creek Sandstone well is <br />summarized on Tables 5 and 6. A plot of field conductivity measurements is presented in Figure 13. Note <br />that conductivity values for the No. 5 Mine well appear elevated to levels seen in the early 1980's, but appear <br />to be in the same range as the former Okie Plaza well. This may be related to consistent pumping at this site. <br />Note that the No. 5 dewatering pump was damaged during the fourth quarter of 2010, and was removed and <br />replaced with another pump in June 2011 when the area was dry enough to bring in a crane. <br />The field parameter data for the three Middle Sandstone wells (TR-4, TR -7A, 81 -01) was reviewed. Water <br />quality data are summanzed in Tables 7 through 12. Plots of field conductivity for these Middle Sandstone <br />Wells are presented in Figure 14. The conductivity measurements recorded at well TR -7A remain stabile as <br />compared to historic values. However, it has Middle Sandstone wells TR-4 and 81 -01 exhibited elevated <br />conductivity values since monitoring was re- initiated in 2006. Williams Fork will continue to monitor these <br />sites in order to ascertain a possible reason for this effect. In 2007, Williams Fork verified that the contractor <br />(Miller Water Monitoring Service) was sampling the appropriate well. <br />Wells TR -7A and TR-4 have historically indicated a slight reduction in concentrations of major ions over <br />time. Historically, all three wells have shown a reduction in concentrations of iron which shows considerable <br />vanation in concentrations. The general reduction in iron concentrations may be the result of better purging <br />of well bore volumes prior to sampling. <br />The 2011 field parameter data for the two Twentymile Sandstone well 259, does not suggest a significant <br />impact or trend. However the 9 Mine well Exhibited a rise in conductivity in early 2011. Water quality data <br />for these Twentymile Sandstone wells are summarized in Tables 13 through 16. Plots of field conductivity <br />over time are presented in Figure 15. Measurements for well 259 during 2011 appeared consistent with <br />historic values. Williams Fork will continue to monitor 9 Mine well to see what trends are for 2012. <br />In summary, elevated conductivity values were detected in the Trout Creek and Middle Sandstones. However <br />the overall water quality of these, as well as the Twentymile Sandstone does not indicate obvious adverse <br />impacts related to Mines 5 and 6. <br />Note that the 7 North Angle well pump did not operate in 2011, and has not been operated for discharge since <br />about 2003. The No. 5 Mine pump was the only active pumping performed at the mine in 2011, although as <br />mentioned earlier, the pump failed the last quarter of 2010 through June of 2011, so no water was pumped. <br />The No. 5 mine pump is run to maintain appropriate mine water levels. A plot of the measured discharge for <br />this point is presented in Figure 16. Figure 17 is a monthly tabulation of flow measurements for 2011. <br />3.1.2 Mine Water Discharge <br />Summanes of the water quality data for mine discharge sites are presented in Tables 17 through 20. The No. <br />5 Mine well discharge is Colorado Department of Public Health and Environment's (CDPHE's) CDPS <br />discharge point 003. The 7 North Angle discharge is CDPS discharge point 024 (which did not flow in 2011). <br />Summanes of the available water quality data for the mine discharge sites are presented in Tables 17 through <br />20. <br />The No. 5 Mine discharge water quality (Figure 18) indicates dissolved solids concentrations consistent with <br />historic values (typically under 1000 mg/L), consistent with pre - Temporary Cessation values. There was no <br />discharge from the 7NA well in 2011. The average total dissolved solids (TDS) concentration for the No. 5 <br />Page 5 <br />G \Environmental \EMPIREWILLIAMS FORK\AHR\2011 \Empire2011AHR doc <br />