Laserfiche WebLink
2016 Recommended Modifications to the West Elk Mine Hydrologic Monitoring Network 6 <br />Figure 1. Flow in Spring G-25 <br />Time -series water quality data from Spring G-25 do not indicate any mining related adverse <br />trends in water quality. The laboratory ECs for this spring for the period of record show a slight <br />increasing trend, ranging from 1,214 to 1,990 µmhos/cm and averaging about 1,705 µmhos/cm. <br />In comparison, the baseline laboratory EC values range from 777 to 1,320 µmhos/cm. TDS <br />values for this spring for the period of record also show an increasing trend, ranging from 996 to <br />1,350 mg/L, and averaging about 1,161 mg/L, compared to baseline values ranging from 336 to <br />1,170 mg/L. These increasing trends have occurred long after mining was completed below this <br />spring (May 1995), and are most likely related to increased sedimentation from higher flows <br />since 2005 (Figure 1). <br />There are no baseline values for field pH for this site (WWE, 2001) for comparison; however, <br />baseline certified laboratory pH data are available for comparison. The field pH values for this <br />spring over the period of record are relatively steady, ranging from 6.77 to 7.92 s.u., and <br />averaging about 7.40 s.u. In comparison, the baseline laboratory pH values range from 6.85 to <br />8.50 s.u. Total suspended solids (TSS) values for this spring for the period of record range from <br />not detected (ND) to 14 mg/L, compared to the maximum baseline value of 26 mg/L. Dissolved <br />iron values range from ND to 0.14 mg/L, compared to the maximum baseline value of 0.135 <br />mg/L. Total iron values range from ND to 0.63 mg/L, compared to the maximum baseline value <br />of 0.99 mg/L. The time -series water quality graphs for Spring G-25 are shown in Figure 2. <br />August 2016 HydroGeo, Inc. <br />