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West Elk Mine 2016 Surface Water and Groundwater Quantity and Quality Data Summary 22 <br />Table 11. Summary of Well Water Quality Parameters Elevated 10 Percent or <br />More above Baseline Maximum Values <br />Site Name <br />Sample Date <br />Parameter <br />Units <br />Result <br />Baseline <br />Maximum <br />Value <br />Upper Dry Fork Alluvial <br />Well <br />9/5/2016 <br />Conductivity @25C <br />µmhos/cm <br />860 <br />509 <br />9/5/2016 <br />Residue, Filterable JDS) @180C <br />mg/L <br />548 <br />390 <br />Lower Dry Fork <br />Alluvial Well <br />5/2/2016 <br />pH (Field) <br />SU <br />8 13 <br />7.10 <br />5/27/2016 <br />802 <br />Well SOM-80 <br />9/6/2016 <br />Conductivity @25C <br />µmhos/cm <br />1,040 <br />897 <br />9/6/2016 <br />(Duplicate)1,040 <br />Well SOM-45-1-1-1 <br />5/5/2016 <br />Conductivity (Field) <br />µmhos/cm <br />1,957 <br />1,626 <br />5/27/2016 <br />1,902 <br />9/6/2016 <br />1,969 <br />9/6/2016 <br />Conductivity @25C <br />µmhos/cm <br />1,970 <br />1,390 <br />9/6/2016 <br />Iron, total <br />mg/L <br />705 <br />615 <br />Well 03-11-1 <br />9/7/2016 <br />Conductivity @25C <br />µmhos/cm <br />3,060 <br />2,730 <br />3.3.2 Impacts to Groundwater Quantity <br />Routine (post -baseline) monitoring of groundwater levels in the monitoring wells is <br />conducted three times per year, corresponding with rising limb, peak flow, and low flow <br />periods. Groundwater level and elevation data for the monitoring wells for the period of <br />record are summarized in Appendix F. <br />Mining operations appear to have impacted the groundwater levels in several wells, but <br />levels may also have been impacted by drought conditions in recent years. The water <br />level drop in the following wells may be mining related, due to the up -gradient diversion <br />of surface water runoff in the area. Wells GP -3, RPE -7, and GP -4 have been dry for <br />multiple years and have remained dry to nearly dry through WY 2016. Wells RPE -1 and <br />RPE -7 did not have enough water to collect a sample in WY 2016. As noted in Section <br />3.3, the casing in numerous wells has collapsed due to mining related subsidence, and <br />there were pronounced water level drops in several of these wells immediately prior to <br />the casing collapse. <br />4.0 ADEQUACY OF THE MONITORING PROGRAM <br />MCC's hydrologic monitoring program operates in accordance with CDRMS Permit No. <br />C-1980-007, as revised by Technical Revision No. TR -88 and Permit Revision No. PR - <br />10. PR -10 includes a revised comprehensive hydrologic monitoring plan for the entire <br />permit area including the SOD mine plan area. A more detailed description of the <br />hydrologic monitoring plan is presented in Exhibit 71 in the permit document (CDRMS, <br />2006). It should be noted that a new revised hydrologic monitoring plan was approved <br />by the CDRMS in 2016 (CDRMS, 2016) and will be implemented in WY 2017. <br />June 2017 HydroGeo, Inc. <br />