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West Elk Mine Stock Watering Ponds and U.S. Forest Service Water Resources The stock watering ponds in the South of Divide mining area aze located in debris flows or colluvium derived from the debris flows (Dunrud 1989). A total of 26 ponds have been mapped in the South of Divide mining area. Ten of these ponds aze also classified as U.S, Forest Service water resources. The debris flows consist of a heterogeneous mixture of clay derived from the Wasatch Formation and boulders and gravels derived primarily from the Mount Gunnison intrusive (granodiorites and quartz monzanites). Based on observations made during geologic mapping in the azea, these debris flows are even less likely to be affected by longwall mining than the alluvium The debris flows have a very low permeability and, because the clay matrix is armored by the interstitial gravel and boulders, aze resistant to erosion (the Deep Creek Ditch locally flows in this material at steep gradients). Based on the above-mentioned observations, no effects are expected when ponds in the South of Divide mining azea are undermined. The clay-rich material that lines these ponds is expected to provide a seal against any subsidence effects. Stock watering ponds conditions will be surveyed, accessible, before they aze within twice the angle of draw. A second survey will be conducted within three months after they aze no longer in the angle of draw. No stock watering ponds in the Apache Rocks and Box Canyon mining areas have been noticeably affected when longwall mining occurred beneath them. The ponds above mined longwall panels 13-A, I5, 16, and 22 in Horse Gulch, Sylvester Gulch (stock ponds P27-2 and P27-3), and West Flatiron (stock pond P23-4) respectively, showed no noticeable water level change when compazed to pre-mining water levels (after taking seasonal precipitation levels into • account). These ponds, which aze located in clay-rich (Wasatch clay) material in order to minimize leakage, occur in overburden that ranges in depth from about 800 feet in Horse Gulch to 2,200 feet in the stock pond P23-4 above the eastern end of mined longwall pane122. Streams and Ditches The primary streams in the South of Divide mining area are Dry Fork of Minnesota Creek, Deer Creek, Poison Creek, and Lick Creek. The primary source of water to Minnesota Reservoir comes from the Deep Creek Ditch, wherein water is diverted from the upper drainage of Deep Creek and transmitted to Dry Fork. The Deep Creek ditch was constructed in debris flows or colluvium and alluvium derived from the debris flow, as described above, this debris flow material is not expected to be impacted by longwall mining. As discussed in Section 5.3.2 of Exhibit 60B, no cracks were observed in the alluvium and colluvium of Sylvester Gulch and Deep Creek during periodic field observations in the Apache Rocks and Box Canyon mining areas. The near-surface alluvial material consists of primarily sand, silt, clay, and soil that range in estimated thickness from 25 to 150 feet. In the two areas mentioned the drainages were located above rigid pillazs and panel boundaries where the overburden depth ranges from 800 to 1,050 feet. The alluvium in Dry Fork and Lick Creek, which also has an estimated thickness range of 25 to 150 feet, contains more clay than does the Deep Creek alluvium. Therefore, it is even less likely that cracks will occur in colluvium and alluvium in the stream valleys of the South of Divide mining azea. • 1.05-136 Revised November 2004 PRIO