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~, ,~,,~ J~, _2_ ', L'~ tl ~~~~ Colorado Yampa Coal Company proposes to dispose of underground development waste removed from the Foidel Creek Mine's underground workings in an area near the southwestern terminus of the existing Energy No. 1 Mine's surface pit. The applicant proposes to construct a 300 foot wide earthen barrier berm between the waste disposal area and the portal area of the Foidel Creek Mine, as depicted on Map 4a and in cross-section Z-Z' on Map lla. The underground development waste will be deposited above the observed static water table (6825 ft. above sea level). Upon the cessation of mining at the Foidel Creek underground mine, the entire underground development waste disposal area will be backfilled to final post-mining topography with overburden spoil from adjacent previously-mine~~~reas. The Division finds that the proposed underground developm i?"~disposal plan presented within the permit application is in conformance with the regulations of Rule 2.06.3(6)(b) and 4.09. XXVIII. Coal Processing Waste and Non-Coal Processing Waste (2.05.3 ~ nc nT~1Tc~ n in n iii The applicant proposes no processing of coal within the application and, therefore, will not generate coal processing waste. XXIII. Subsidence (2.05.6(6), 4.20) Colorado Yampa Coal Company has completed an inventory of potentially affected structures and renewable resource lands within the permit and adjacent areas of the Foidel Creek Mine. This inventory identified several structures which exist within or adjoining the potentially affected area, including 2 unoccupied but habitable structures, the CYCC mine office, and portions of County Road No. 27 and a Denver and Rio Grande Western Railroad spur. In addition, the inventory identified renewable resource lands comprised by Foidel Creek and its adjoining surficial alluvium and the Twentymile Sandstone aquifer. The application contains a subsidence prediction, within Exhibit 5a. This projection involves prudent state-of-the-art methods for delineating the potentially affected areas, assuming an angle of draw of 250. Projection of this angle of draw from the proposed underground workings to the ground surface determined that none of the inventory's structures lie within the potentially effected area, with the exception of the segments of County Road No. 27 and the Denver and Rio Grande Western Railroad spur which pass above the portal entryway mains. (See Map 4a) Exhibit 5a of the application also includes a stability analysis for a main entryway configuration proposed by the applicant to prevent subsidence of the surface above those entryways. This analysis, using material strength parameters derived from testing of cored samples of the coal, floor and overburden materials, and accepted analytical methodology developed by Wilson and Ashwin, projects a factor of stability in excess of 2.4 for the proposed pillar and entry configuration. This relatively limited extraction configuration recovers less than 40% of the resource in-place.