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West Elk Mine 2013 Annual Hydrology Report 54 <br />corresponding to the rising limb, peak flow, and low flow sampling rounds. Routine <br />monitoring (post- baseline) includes collecting a sample for laboratory analysis one time <br />per year during the low flow monitoring round. A summary of the groundwater <br />monitoring well characteristics is presented in Table 6 and the monitoring schedule is <br />summarized in Table 7. The locations of the groundwater monitoring wells are shown on <br />Map 2. The well water elevation and depth to water data are presented in Appendix F <br />and the groundwater quality data are presented in Appendix G. <br />The casings in numerous monitoring wells have collapsed in the past several years, as a <br />result of mining- induced subsidence or they have been blocked or damaged from other <br />causes. It was not possible to collect reliable water quality and /or water level data from <br />the following damaged wells in WY 2013: <br />a SOM -2 -H (July 1999; mine - induced collapsed casing) <br />a SOM -16 -H (September 2000; mine - induced collapsed casing) <br />a 96 -27 -1 (April 2002, mine - induced collapsed casing), <br />a SO.W -1 (June 2002, mine - induced collapsed casing) <br />a SOM- 45 -H -1 (September 2002; mine - induced, collapsed casing) <br />a SOM- 23 -H -1 (August 2006, faulty construction, broken and collapsed casing) <br />a SOM 13 (April 2007, poor construction, obstructed casing), <br />a SOM 129 -H (May 2008, casing damaged at surface; unreliable water quality <br />and water level due to frequent dirt and runoff water infiltration) <br />a SOM- 23 -H -2 (June 2008, poor construction, obstructed casing) <br />a SOM -313 (August 2008, obstructed casing from grease and mud buildup) <br />a SOM -3E (May 2011, obstructed casing, bailer stuck at about 302 ft) <br />a 96 -2 -2 (April 2007 and August 2011, well casing collapsed at 720 ft in WY <br />2007, additional collapse at 433 ft btoc in April 2012) <br />a SOM- 23 -H -3 (August 2011, lined with grease) <br />a SOM- 23 -H -4 (May 2013, poor construction, obstructed casing) <br />5.4.1 Impacts to Groundwater Quality <br />Groundwater quality data are collected for permit - specified parameters at monitoring <br />wells throughout the permit area, in order to detect potential impacts of mining activities <br />to groundwater resources. Potential impacts to groundwater are determined by <br />comparison to baseline values and consideration of climatic conditions. Field pH values <br />were used for comparison when they were available, as the holding time for the lab pH is <br />typically exceeded, due to the shipping time required for samples to reach the analytical <br />lab. Overall, there were only minor notable water quality changes in a few of the <br />groundwater monitoring wells during WY 2013 (Appendix G). <br />No water quality data are available for the following six wells because they were dry or <br />did not have enough water to collect samples during the low flow sampling period in WY <br />2013: GP -3, GP -4, GP -7, RPE -1, RPE -7, and SOM -C76. No sample was collected from <br />SOM- 23 -H -4 in WY 2013 and no future samples will be collected at this site, because the <br />well casing is obstructed. Wells GP -6 and GP -7 do not have baseline data for <br />comparison. <br />June 2014 HydroGeo, Inc. <br />