2009-01-23_REVISION - C1980007 (3)

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X. Backfilling and Grading • The Backfilling and Grading plan can be found throughout Section 2.05.4. Exhibit 54 of the permit document contains detailed information regarding abandonment and sealing of portals. Maps 58, 58A, 58B, and 59 show post-mining topography. During the course of MCC's study of the original West Elk lease property and the Jumbo Mountain lease area, numerous slope failures and rock falls were identified. Landslides and rockfalls identified during their study are delineated on Map 32 and 32A. However, MCC also observed that it believes such slope problems would have a minimal effect on the operation and these areas can be stabilized or removed when the facility is built. In order to judge the credibility of MCC's statements regarding slope stability, the Division requested the submittal of supporting information. MCC responded by submitting a report prepared by Geo-Hydro Consultants, Inc., entitled "Landslide Study, Geo-Hydro Consultants, Mt. Gunnison No. 1 Mine, included within the permit document in Exhibit 14. This report, prepared in conformance with the current state-of-the-art, includes design recommendations for the surface facilities to be constructed within the landslide deposit delineated in the surface facility area of the West Elk Mine site. One of the design recommendations forwarded within the report is the installation of a dewatering system consisting of horizontally inclined dewatering wells installed throughout the affected area, specifically within the portal bench and access road. Specific engineering design plans for this system have been included • within the permit document. In addition, intricate bin-wall retaining structures were subsequently included within the design documents in the permit section. The area of the surface facilities has been the focus of historic and recent landslide activity. The Division required MCC to demonstrate, through appropriate geotechnical analyses, that the proposed backfilled surfaces would satisfy the required static slope safety factor of 1.3. Merrick and Company prepared a "Report of Stability Analyses and Recommendations for Reclaimed Surface Facilities at the West Elk Coal Company, Mt. Gunnison No. 1 Mine." The report presents the results of the required stability analyses and recommendations for reclamation of the affected area. MCC proposes to return all surface disturbed areas to approximate original contour, with the exception of the waste disposal sites. XI. Revegetation Information regarding the vegetation in the West Elk Mine permit area is found in Section 2.04.10, 2.05.4, Exhibit 31, 32, 33, Map 42, 43, and 44 of the permit document. No threatened and/or endangered plant species were found anywhere within the permit area. • Success of revegetation efforts was originally based on reference areas established in July 1980 and enlarged in 1981. Reference areas were established for mixed shrub and dry meadow communities and were shown on Map 44. 44