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West Elk Mine <br />Approximately seven months following the B Seam mining beneath SOM 38-H-1, the casing of <br />the well was apparently blocked or distorted, thus prohibiting additional water level monitoring. <br />The 1993 Annual Hydrology Report attributes the loss of this well to subsidence. However, B <br />Seam longwall mining was occurring at that time in panel 2NW more than 800 feet away from <br />well SOM 38-H-1 on the opposite side of 200 foot wide chain pillazs dividing the 1NW panel <br />from the 2NW Panel. Following complete mining of the 2NW Panel, no further blockage was <br />observed and a water level was measured in Mazch 1995. Further monitoring of this well was <br />then continued. <br />Monitoring well SOM C-72-H is located above the chain pillazs between panels SNW and 6NW. <br />This well is completed immediately above the B Seam and is well within the expected subsidence <br />cave zone. As expected, while advancing the SNW longwall panel, the casing was appazently split <br />and offset sufficiently to disallow continued water level measurements. Figure 25 shows the <br />reaction of the water level in the well as it was approached (December 1994) and finally lost <br />(January 1995) to the longwall mining operation. The water contained within the monitored water- <br />bearing unit immediately above the B Seam was probably lost to the mine workings. However, did <br />not observe an increased seepage or inflow in the azea of SOM C-72-H as the longwall face was <br />advanced through the area. <br />In February 1995, water level probes were once again able to reach the bottom of monitoring <br />well SOM C-72-H. At that time, sufficient recompression of the area azound the well due to <br />adjacent area subsidence had occurred to allow for water level observation equipment. As <br />• expected, no groundwater was observed at that time. Monitoring wells SW-1 through SW-6 aze <br />all located along the eastern edge of the 1NW longwall panel. Each of these wells is <br />approximately 60 feet deep and completed in the Barren Member of the Mesaverde Formation. <br />Due to the deep overburden cover, these wells would not be expected to show effects resulting <br />from fractures extending up from the mine. However, they aze valuable for detecting effects of <br />surface cracks on shallow groundwater. Figure 26 and Figure 27 shows the observed water <br />levels in the wells since initial observations in 1988. Each of these wells shows consistent water <br />levels at or slightly above the bottom of the well even as the 1NW longwall panel face advanced <br />beneath them. This observation is significant because there is a documented surface or tension <br />crack of approximately 100 linear feet in length between monitoring wells SW-5 and SW-6 <br />which developed sometime prior to its first observation in August 1993. Despite this crack, <br />water levels in SW-5 and SW-6 have remained constant. These observations indicate that <br />surface cracking, to the degree that it exists in the azea, does not extend into the water-bearing <br />zones into which wells SW-5 and SW-6 aze completed (approximately 40 to 60 feet below the <br />ground surface). This is consistent with Mr. Dunrud's assessment of surface cracking, as <br />discussed eazlier in Section 2.05.6 and Exhibit 60. <br />MCC encountered poor roof conditions and initial colluvial inflows of 50 gpm while mining the <br />bleeder entries at the north ends of panels 6NW and 7NW. These inflows diminished to neazly <br />zero over a few weeks. These locations aze beneath Lone Pine Gulch and have an overburden <br />thickness of 300 to 400 feet. <br /> <br />7.05-267 Revised Jwie 1005 PRl0; Rev. March 2006 <br />