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The highwall reduction area and spoil will be worked together to shape and blend the material into the • <br />natural topography, creating a transition that prevents drainage from creating knickpoints, propagating <br />natural undisturbed slopes, and enhancing the post mining land use. <br />The postmining topography in the North Valora Pit has been modified to accommodate both ongoing <br />backfilling and grading in this area and establishment of the alternate haul road necessary to replace <br />the lower portion of Haul Road D, which has been impacted by the stability problems above Pond 012. <br />The final slope configuration in the lower portion of the North Valora Pit will be completed in 2006 <br />when the haul road is removed and lower end of Channel YPM-6 is constructed (the material removed <br />from the haul road and channel area will need to be placed against the northern side slope to achieve <br />PMTI~ See Exhibit 19-1A, Backfilling and Grading Plan, for location of this variance area and <br />reclamation schedule. <br />The localized change in postmining topography results in steepening (from approximately 4.9:1 to <br />3.5:1) of an 800' section of the slope along the north highwall, but generally maintains the overall <br />gradient of Postmining Channel YPM-7. The new 3.5:1 slope is well below the natural angle of repose <br />for spoil materials, is compatible with the objective of long-term slope stability and existing natural <br />slopes in the area, and meets the applicable general grading requirements of Rule 4.14.21111b1. <br />SCC recognizes that post-reclamation natural settlement has the potential to result in limited exposure <br />of portions of the North Valora Pit highwall. SCC will address the settlement and highwall exposure <br />concern by monitoring this area for settlement, surface cracks, and any highwall exposures. It is • <br />anticipated that any surface cracks or highwallexposures that may occur will be localized and of <br />limited extent and can be repaired by minor regrading and reseeding. <br />Thin or thick overburden as defined by Section 4.14.4 and 4.14.5 does not exist at the Yoast Mine. <br />The final volume is greater than 0.8 of the initial volume, therefore the thin overburden criteria is not <br />applicable. The thick overburden rule does not apply because the final volume is not greater than 1.2 <br />of the initial volume. Please refer to the volume calculations on Table 20-1, Post Mining Landform <br />Mass Balance. <br />Box cut spoil will initially be placed onto unmined land as described in Tab 12, Coal Resource Recovery <br />Plan. This material will be rehandled when the dragline returns to the box cut arealsl. Portions of box <br />cut spoil will be temporarily stored in approved locations above the highwall for backfill info portions of <br />the final pits. All vegetative and organic material and topsoil will be removed from the area where box <br />cut spoil is placed, and the spoil graded both into the mined area and blended into the surrounding <br />terrain. No material shortages or excessive disturbed areas are anticipated in the area of the final <br />highwall or major spoil excesses in the box cut area. This can be determined by reviewing Exhibit 12- <br />1, Operations Plan, and the pre- and post mining topography slopes as shown on Exhibit 20-2A, Pre- <br />Mining and Post Mining Cross-sections. <br />• <br />PR-02 2 Revised 03/05 <br />