2009-10-30_PERMIT FILE - C1982056A (5)

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NMD and WMD (Panels 17 -Right through 24- Right, and 12 -Left through 17 -Left, PR 03 -06, PRO6 -07, PRO9 -08, TR07 -63, and TR08 -64) • Mining will continue to the northern limit of the NMD, and development will be initiated in the WMD, progressing through full development and longwall mining. Mining in both the NMD and WMD will result in subsiding portions Fish Creek and its associated Alluvial Valley Floor, isolated stock ponds, the Twentymile Sandstone, powerlines (located over the 19 -Right Panel, the 9NM entries, and paralleling RCR27), and the Union Pacific Railroad Track (located over the 12- through 17 -Right Panels). Each of these affected surface structures or resource values are discussed in the following sections. Initial Phase I, and Phase II and III development in the WMD will be limited to main and sub -main entries, with retention of support and barrier pillars, with no subsidence over these areas. Subsidence in the WMSD will not occur until longwall mining is initiated in Panel 17 -Left. Land Use Pastureland and rangeland are the dominant land uses in the remaining section of the NMD and over the entire WMD. The land -use patterns are presented in Map 3, Premining Land Use. Existing Structures Aquifers - The Twentymile Sandstone outcrops along sections of the Foidel and Middle Creek drainages and overlies the Wadge Coal Seam over most of the NMD and WMD. The Twentymile Sandstone is a marginal regional aquifer which extends throughout much of Northwest Colorado. There are no known water supply wells completed in the Twentymile Sandstone in the vicinity of the mine. County Roads 27 and 37A and Ranch Roads - TCC will undermine and subside Routt County Roads 27 (RCR27) and 37A (RCR37A) during mining of Panels 13- through 17 -Left in the WMD. RCR27 is an asphalt - paved all- weather road, while RCR37A is a gravel- surfaced secondary road. It is anticipated that a maximum of 69 inches of subsidence will occur where the existing road (RCR27) crosses the center of the longwall panels. Recognizing that subsidence will be incremental across each panel (ie: minimal over each gateroad, and gradually increasing to the maximum at the center of each 1,000 -foot wide panel), subsidence - related changes in road elevation and gradient (maximum change in gradient will be approximately 1.2 percent, or 1.2 feet per 100 feet). will probably not be noticeable. TCC has previously subsided portions of RCR27 and RCR33 in the SWMD and EMD, with no significant impacts on either the roads or their continued effective use. The roads were visually monitored during and following mining and subsidence, and some localized cracking of the asphalt surface was noted. Cracks were generally small (maximum width of 2 -3 inches), and were repaired by filling the cracks with hot tar /asphalt. Several ranch roads traverse the planned longwall panels that will be subsided by mining. Use of these roads is limited to TCC personnel and surface landowners, with no use by the general public (access controlled with locked gates. Subsidence may result in minor surface cracks, which will be repaired by regarding the roads. Powerlines - The powerlines located to the north of the 18 -Right gateroad and within the 19 -Right Panel, will be subsided during mining in this portion of the NMD. The powerline is adjacent to the gateroad, so subsidence will be limited, in addition, TCC's extensive mining experience indicates that this powerline will not be negatively impacted. The subsidence report for the powerlines in the NMD is presented in Exhibit 7e -7. The powerlines previously discussed, as being subsided in the EMD, extend over portions of the 9NM entries. There is also a 69KV Yampa Valley Electric powerline that generally parallels RCR27 on the east side, which overlies Panels 17- through 13- Right. The 69KV powerline is supported on wooden "H" structure poles. The worst- • case subsidence effect on these structures would be tilting of the structures. TCC has undermined and subsided this type of structure in the SWMD, EMD and NMD, and has observed minor tilting of the poles. Due to the inherent flexibility of the wooden poles, the integrity of the structures was not affected, the poles remained intact, and they continued to function with no loss of service. TCC anticipates a similar response for the wooden structures located in the WMD. PRO9 -08 2.05 -181.9 04/29/09