2016-11-18_PERMIT FILE - C1981019A (7)

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RULE 2 PERMITS mining operations in the pit, Colowyo is committed to reclamation in accordance with Rule 4.13 and will perform reclamation activities as contemporaneously as practicable with the South Taylor mining operations. With the limitation of areas available for reclamation prior to final pit backfill, Colowyo is proposing to reclaim the out slopes of both valley fills as shown on Map 29 A, prior to final pit closure. It is anticipated that the South Taylor pit will reach a steady state operation in 2012; where as all spoil material produced in the advancing cut will be back -casted into previously mined areas. In general, it is anticipated that the vast majority of reclamation activities in the South Taylor pit area will begin in the lower elevation areas and progress upslope to the highest elevation areas. This is a matter of practical necessity due to the operational constraints encountered in the area which were also reflected in the hydrological modeling found in Exhibit 7, Item 20. Major departures from this premise will result in the need to revisit the adequacy of the sediment control structures designed and submitted as part of this permit revision. 2.05.4 (2)(b) Reclamation Costs The estimate of the cost of reclamation of the operations required to be covered by the performance bond is found under Rule 3. 2.05.4 (2)(c) Backfilling Plan As the mining progresses to the southeast, overburden material from each successive cut will be backfilled into the previously mined out area and the additional spoil will continue to buildup in previously mined areas, thus creating a large in -pit temporary spoil pile. This cycle will be repeated for the entire mining area. Due to shape, size and depth of the South Taylor pit, results in leaving the majority of the spoil backfilling process until final pit closure. As a result, Colowyo has officially requested a variance for a delay in contemporaneous reclamation based on Rule 4.14.1(1)(d) which states that "Rough backfilling and grading shall be completed within 180 days following coal removal and shall not be more than four spoil ridges behind the pit being worked..". The mining techniques utilizing dragline and truck/shovel operation are shown in detail on Mining Range Diagram (Map 24A), and show the approximate distance between topsoil removal and replacement. Premining topography is presented on Map 18A and the postmining topography is shown on Map 19B. Map 20B provides cross-sections of the premining and postmining topography. Map 28B presents the topsoil handling movements and the timing of stripping activities. Map 29A shows the spoil grading sequence timing of reclamation activities. The backfilled mining areas will be graded to establish a stable post mine topography that blends into the undisturbed areas outside the mining limits (Map 1913). Colowyo will grade all final slopes so that overall grades do not exceed 33% (Map 2013). Additional information on the backfilling and regrading plan are discussed further in Volume 1, Section 2.05.4 and Section 4.14. 2.05.4 (2)(d) Topsoil Salvage Prior to any mining -related disturbances, all available topsoil will be removed from the site to be disturbed as discussed in Section 2.05.3, and will be redistributed or stockpiled as necessary to satisfy the needs of the reclamation timetable. Final grading before topsoil placement will be conducted in a manner that minimizes erosion and provides a surface for the topsoil that minimizes slippage. If spoil compaction is a problem, the spoil will be ripped with a dozer to minimize compaction, assure stability and minimize slippage after topsoil replacement. The average uniform topsoil replacement depth will be 19.8 inches as determined by the topsoil salvage calculations shown on Tables 2.04.9-6, 2.04.9-6A, and 2.04.9-7. Topsoil may be applied at depths that are lesser or greater than the specified depth in selected areas where plants, that may require South Taylor/Lower Wilson — Rule 2, Page 77 Revision Date: 11 / 18/16 Revision No.: MR -163