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West Elk Mine <br /> <br />2.05-112 Rev. 06/05- PR10, 03/06- PR10, 05/06- PR10, 11/060- TR107, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11/10- MR372; 10/20- MR-452; <br /> 12/20- TR149; 12/21- TR150, 1/24-TR152 <br />Mining of the longwall mining panels in the South of Divide mining area did not affect <br />Minnesota Reservoir. The reservoir is located outside the area of mining influence, using the <br />most conservative angle of draw. Measured ground subsidence nor seismicity caused by <br />longwall mining affected Monument Dam and Minnesota Reservoir. <br />Water Resources <br />Stock Watering Ponds and U.S. Forest Service <br />The stock watering ponds are typically located in debris flows or colluvium derived from the debris <br />flows (Dunrud 1989). Several stock watering ponds were mapped in the mining areas (for more <br />information see Section 2.2 of Exhibit 71 & 71A). Some of these ponds were also classified as U.S. <br />Forest Service water resources. The ponds in the permit area have been photographed on the <br />ground on an annual basis beginning in 2005. The debris flows consist of a heterogeneous mixture <br />of clay derived from the Wasatch Formation and boulders and gravels derived primarily from the <br />Mount Gunnison intrusive (granodiorites and quartz monzanites). Based on observations made <br />during geologic mapping in the area, these debris flows are even less likely to be affected by <br />longwall mining than the alluvium. The debris flows have a very low permeability and, because the <br />clay matrix is armored by the interstitial gravel and boulders, are resistant to erosion (the Deep <br />Creek Ditch locally flows in this material at steep gradients). Based on the above-mentioned <br />observations, no effects are expected when ponds in the South of Divide mining area are <br />undermined. The clay-rich material that lines these ponds is expected to provide a seal against any <br />subsidence effects. Stock watering ponds conditions will be surveyed, when accessible, before they <br />are within twice the angle of draw. A second survey will be conducted within three months after <br />they are no longer in the angle of draw. Stock ponds will be surveyed assuming climatic and ground <br />conditions allow reasonable and safe access for this and other monitoring. <br />No impacts to stock watering ponds in the Apache Rocks,Box Canyon West Flatiron, Sylvester <br />Gulch, SOD, Southern Panels, and Sunset Trail mining areas have been noticeably affected to <br />date when longwall mining occurred beneath them. <br />Streams and Ditches <br />The primary streams in the Southern Panels and Dry Fork mining areas are Dry Fork of <br />Minnesota Creek, Deer Creek, Poison Creek, and Lick Creek. South Prong Creek is in the Sunset <br />Trail mining area. The primary source of water to Minnesota Reservoir comes from the Deep <br />Creek Ditch, wherein a trans-basin diversion of water from the upper drainage of Deep Creek is <br />transmitted to Dry Fork. The Deep Creek ditch was constructed in debris flows or colluvium and <br />alluvium derived from the debris flow, as described above, this debris flow material is not <br />expected to be impacted by longwall mining. <br />As is also discussed in the most current versions of Exhibits 55B and 60E, the end of Deep Creek <br />Ditch, where it transitions into Dry Fork, lies above an area that was undermined by panel E5 gate entries. B <br />seam mining may also occur in this area. Annual Hydrology Reports submitted to the CDRMS each <br />year provide monitoring data and note potential impacts from mining.