2016-07-21_REPORT - C1980007 - Laserfiche WebLink

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West Elk Mine 2015 Surface Water and Groundwater Quantity and Quality Data Summary 20 The casings in numerous monitoring wells have collapsed in the past several years, as a result of mining -induced subsidence or they have been blocked or damaged from other causes. It was not possible to collect reliable water quality and/or water level data from the following damaged wells in WY 2015: • SOM-2-H (July 1999; mine -induced collapsed casing) • SOM-16-H (September 2000; mine -induced collapsed casing) • 96-27-1 (April 2002, mine -induced collapsed casing), • SO.W-1 (June 2002, mine -induced collapsed casing) • SOM-45-H-1 (September 2002; mine -induced, collapsed casing) • SOM-23-H-1 (August 2006, faulty construction, broken and collapsed casing) • SOM 13 (April 2007, poor construction, obstructed casing), • SOM 129-H (May 2008, casing damaged at surface; unreliable water quality and water level due to frequent dirt and runoff water infiltration) 0 SOM-23-H-2 (June 2008, poor construction, obstructed casing) • SOM-313 (August 2008, obstructed casing from grease and mud buildup) • SOM-3E (May 2011, obstructed casing, bailer stuck at about 302 ft) • 96-2-2 (April 2007 and August 2011, well casing collapsed at 720 ft in WY 2007, additional collapse at 433 ft btoc in April 2012) • SOM-23-H-3 (August 2011, lined with grease) • SOM-23-H-4 (May 2013, poor construction, obstructed casing) 3.3.1 Impacts to Groundwater Quality Groundwater quality data are collected for permit -specified parameters at monitoring wells throughout the permit area, in order to detect potential impacts of mining activities to groundwater resources. Potential impacts to groundwater are determined by comparison to baseline values and consideration of climatic conditions. Field pH values were used for comparison when they were available, as the holding time for the lab pH is typically exceeded, due to the shipping time required for samples to reach the analytical lab. Overall, there were only minor notable water quality changes in a few of the groundwater monitoring wells during WY 2015 (Appendix G), these changes are likely the result of sediment in the well not related to mining induced effects. No water quality data are available for the following wells because they were dry or did not have enough water to collect samples during the low flow sampling period in WY 2015: GP -3, GP -4, RPE -1, RPE -7, and SOM-C76. Wells GP -6 and GP -7 do not have baseline data for comparison (WWE, 2001). Well 01-11-1 did not have any parameters elevated 10 percent or more over baseline maximums in WY 2015. Wells where tested parameters were elevated 10 percent or more above maximum baseline values are summarized in Table 11. June 2016 HydroGeo, Inc