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-50- <br />XVII. <br />WECC stated in its original permit application that numerous slope <br />failures and rock falls have been identified during the course of <br />its study of the Mt. Gunnison lease property. Landslides and <br />rockfalls identified during their study are delineated on map <br />Exhibit 2.7.9.A. However, WECC also observed that it believes such <br />slope problems would have "minimal effect on the operation...such <br />areas, if they are encountered, can be stabilized or removed when <br />the facility is built". (Page 2-242, permit application.) <br />In order to judge the credibility of WECC's permit app]ication <br />statements regarding slope stability, the Division requested the <br />submission of supporting information. WECC responded by submitting <br />a report prepared by Geo-hydro Consultants, Inc., entitled <br />"Landslide Study, Geo-Hydro Consultants, Mt. Gunnison No. 1 Mine", <br />included within the revised permit application as exhibit 2.7.9. <br />This report, prepared in conformance with the current <br />state-of-the-art, includes design recommendations for the surface <br />facilities to be constructed within the landslide deposit <br />delineated in the surface facility area of the Mt. Gunnison site. <br />One of the design recommendations forwarded within the report is <br />the installation of a dewatering system consisting of horizontally <br />inclined dewatering wells installed throughout the affected area, <br />specifically within the portal bench and access road. Specific <br />engineering design plans for this system have been included within <br />the permit application. In addition, intricate bin-wall retaining <br />structures were subsequently included within the design documents <br />in the permit application. Additional concern was also focused by <br />the Division upon landslide deposits above the town of Somerset, <br />and above Beaver and Minnesota Reservoirs. The Division's concern <br />regards possible effects of subsidence upon these previously <br />unstable deposits. This concern has been addressed by WECC. <br />WECC proposes to return all surface disturbed areas to approximate <br />original contour, with the exception of the waste disposal piles. <br />However, WECC has identified an area of the surface facilities <br />which has been the focus of historic and recent landslide activity. <br />Subsequently, the Division required WECC to demonstrate, through <br />appropriate geotechnical analyses, that the proposed backfilled <br />surfaces would satisfy the required static slope safety factor of <br />1.3. Exhibit 3.2.2. within the permit application, "Report on <br />Stability Analyses and Recommendations for Reclaimed Surface <br />Facilities at the WECC Mt. Gunnison No. 1 Mine", prepared by <br />Merrick and Company, presents the results of the required stability <br />analyses and recommendations for reclamation of the affected area. <br />Merrick and Company's recommendations include maintenance of the <br />permanent ground water dewatering system and backfilling many of <br />