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The analysis has been based on these overly conservative figures because of the relative insensitivity of [he surface • lands (over the planned production sections) to subsidence effects. The predictions indicate that the worst case subsidence will not damage the surface land use by adversely affecting drainage or initiating large fractures in the su~cial soils. The impact on the sub-surface hydrology is dealt with in Sections 2.05.6(3). Subsidence effects due to partial undermining of a portion of the Fish Creek drainage in the Westem Mining District did not significantly impact the designated Fish Creek AVF. For the Fish Creek AVF, anticipated subsidence and related effects are evaluated and discussed in Exhibits 7B, 45, and 46, Fish Creek AVF/Stream Study -Subsidence Projections, Hydrologic Analysis and Vegetation Analysis, respectively. The mine training center is at the edge of the predicted subsidence, assuming an angle of draw of 25 degrees. This is the only structure located within [he subsidence limits for the Westem Mining District. TCC believes that no material subsidence damage will occur, as that term is defined in Section 2.06.5.6(e)(ii) with respect to the mine training center, any other structure, or with respect to any renewal resource land. Several high voltage electrical transmission lines traverse across Twentymile Park, but none are located above production panels in the Western Mining District. TCC has undermined several high voltage lines in the Southwest Mining and Eastern Mining District with minimal impact to the lines. SOUTHWEST MINING DISTRICT The mining in the Southwest Mining District did not result in material damage or diminution of reasonably foreseeable use of structures or resources in the area. The following structures and renewable resource lands associated with permit revision number 92-2 include County Road # 27, Fish Creek and its alluvial valley floor, Yampa Valley powerlines and metering station, springs, U.S. West telephoneltnes, T ewT n~tymile Sandstone, and the • old Roger's house, Ponds M & K, Fish Creek Dewatering System, and the Fish Creek Ventilation Fan. The Fish Creek Dewatering System includes two dewatering boreholes, three pond settling systems, control building, an electrical substation, discharge lines and ditches, and topsoil stock piles. The Ventilation Fan includes the fan, building, powerline, pad area, and topsoil stockpile. Routt County Road # 27 will be monitored as per the plan presented in the following section. EMD (Panels 9 Right through 7 Right) The mining of panels 9 right through 7 Right, in the EMD did not result in the material damage or diminution of reasonably foreseeable use of structures or resources in the 1993 mine plan. The structures, which were subsided within the 1993 - 1998 mine plan area, included County Road 33, powerlines (Public Service, Western Area Power Association, Yampa Valley Electric Association, and jointly-owned line), telephone lines (U.S. West), Twentymile Sandstone, Union Pacific Railroad Track (formerly Southern Pacific), Foidel and Middle Creeks. It should be noted that monitoring well 006BRDH7 was subsided and did not experience any significant impacts. ~--- County Road 33 In reference to County Road 33, Twentymile has gained recent experience with undermining and subsiding this road. The experience indicates that either tensional or compressional fractures are manifested in the road L I APPROVED APR 2 4 2000 Permit Renewal No. 3 2.05-182 11/1/99