2018-03-20_PERMIT FILE - C1981019A (3)

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RULE 4 PERFORMANCE STANDARDS material will be temporarily placed above the proposed postmining topography. When the final pass of the West Pit is mined out, this temporarily -placed spoil will be rehandled concurrently with Section 16 virgin and rehandle material to fill and slope the pit to the configuration shown on Map 19 (Postmining Topography). Because the area will be redisturbed by the rehandle activities, that portion of the north end of Section 16 that is above final grade will not be topsoiled or otherwise reclaimed until final reclamation. Final reclamation of the East Pit will take place via the sequence shown on Map 29 (Spoil Grading — South Area) with the reclamation blocks advancing from east to west or from the topographic bottom to the topographic top of the mining areas. Just as in the West Pit, all disturbed areas will be returned to approximate original contour by grading and backfilling with the use of draglines, trucks, dozers, scrapers and dozers assisiting a dragline. As reclamation of the East Pit progresses, all non -reclaimed areas will be contained so that any residual runoff from these areas will be isolated within the remainder of the East Pit. All methods of erosion control and stability such as contour ditches, contour furrows, internal ditches and internal sumps will be established on an as -needed basis to ensure the integrity of the Prospect Pond and the surrounding areas include the final East Pit Ditch. Closure of the East Pit is dependent on the final reclamation and closure of the West Pit as the western most portion of the East Pit will tie-in with the West Pit in this area. A haulroad corridor from the Administration/Shop area to the South Taylor Pit will remain in place until final reclamation is completed in that area. The corridor is sufficient in width to provide a material balance as the corridor is regraded to the post mine topography. The administration/shop/facilities area will be the last area to be reclaimed. A light duty road intended for post mining use may be left as a postmining feature in this corridor with land owner consent. In addition, Colowyo controls additional coal reserves west and south of Section 9 and 16, outside of Permit C-81-019, that may be considered for future mine expansion. It is possible that the final plans for Section 16 and Section 9 could change to provide for such expansion, with any plan changes being addressed through an appropriate permit revision. 4.14.2 General Grading Requirements The final graded slopes at the mining operation will not exceed the approximate original premining slope grade as shown on the Postmining Topography Map (Map 19). Colowyo will retain all overburden and spoil material on solid portions of existing or new benches. The final highwall at the operation will be eliminated by backfilling overburden into the final pit area. Small depressions of a holding capacity slightly greater than one cubic yard of water may be used to create a moist micro climate to aid in shrub establishment. See Section 2.05.4, Planting and Seedings Methods for further information regarding these small depressions. Also, several stock watering ponds will be constructed to compliment the postmining land use. Providing a supply of water is an integral part of the grazing postmining land use. Colowyo will not be mining on any slopes above 20° as shown on the Premining Topography Map (Map 18). Final grading before topsoil placement will be conducted in a manner that minimizes erosion and provides a surface for the topsoil that minimizes slippage. Final grading will be accomplished so that overall grades will not exceed Iv:3h. The plan for backfilling and grading is shown graphically on the Spoil Grading Map (Map 29). Rule 4 Performance Standards 4-38 Revision Date: 1/31/18 Revision No.: TR -119