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-52- XVII. Backfilling and Grading (2.05. WECC stated in its original permit application that numerous slope failures and rock falls have been identified during the course of its study of the Mt. Gunnison lease property. Landslides and rockfalls identified during their study are delineated on map Exhibit 2.7.9.A. However, WECC also observed that it believes such slope problems would have "minimal effect on the operation...such areas, if they are encountered, can be stabilized or removed when the facility is built". (Page 2-242, permit application.) In order to judge the credibility of WECC's permit application statements regarding slope stability, the Division requested the submission of supporting information. WECC 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 revised permit application as exhibit 2.7.9. This report, prepared in conformance with the current state-of-the-art, includes design recommendations for the. surf ace facilities to be constructed within the landslide deposit delineated in the surface facility area of the Mt. Gunnison 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 application. In addition, intricate bin-wall retaining structures were subsequently included within the design documents in the permit application. Additional concern was also focused by the Division upon landslide deposits above Beaver and Minnesota Reservoirs. The Division's concern regards possible effects of subsidence upon these previously unstable deposits. This concern has been addressed by WECC. WECC proposes to return all surface disturbed areas to approximate original contour, with the exception of the waste disposal pile. However, WECC has identified an area of the surface facilities which has been the focus of historic and recent landslide activity. Subsequently, the Division required WECC to demonstrate, through appropriate geotechnical analyses, that the proposed backfilled surfaces would satisfy the required static slope safety factor of 1.3. Exhibit 3.2.2. within the permit application, "Report on Stability Analyses and Recommendations for Reclaimed Surface Facilities at the WECC Mt. Gunnison No. 1 Mine", prepared by Merrick and Company, presents the results of the required stability analyses and recommendations for reclamation of the affected area. Merrick and . Company's recommendations include maintenance of the 5 r - .:~ ., . ..