2009-10-05_PERMIT FILE - C1982057A (2)

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Thin or thick overburden as defined by Rule 4.14.4 and 4.14.5 does not exist at Seneca II-W. The final volume is greater than 0.8 of the initial volume, therefore the thin overburden criterion is not acceptable. The thick overburden rule does not apply because the final volume is not greater than 1.2 of the initial volume. Please refer to page 6 for the volume calculation methodology. Generally, spoil will be stored in an area that is convenient for final placement in the open pit either by dozing or short hauling with screipers. All salvageable topsoil will be removed from the temporary overburden stockpile areas according to the approved plan before any spoil material is placed. If the existing ground is steeper than 20 percent it will be keyed in a manner that increases the stability of the till. The keyway will be a minimum of 20 feet in width and 1 foot in depth. The keyway will begin at the toe of the fill. The overburden material will be placed in horizontal lifts starting at the tae of the stockpile area. The fill slope of the spoil material shall be 2H:1 V or flatter. This slope is flatter than the angle of repose of the spoil material. During and after construction of the stockpile, runoff from upland areas will be prevented from ponding on or saturating the stockpile. Although ditches or berms to control upland runoff are not anticipated, designs for these types of structures will be submitted for approval should they become necessary. The stockpiles will be stabilized by seeding with the approved temporary reclamation seed mix. Box cut spoil will initially be placed onto unmined land as described in Tab 12. This material will be rehandled when the dragline returns to the box cut area(s). Portions of box cut spoil will be temporarily stored in approved locations above the highwall for backfill into portions of the final pits. All vegetative and organic material and topsoil will be removed from the area where box cut spoil is placed, and the spoil graded both into the mined area and blended into the surrounding terrain. No material shortages or excessive disturbed areas are anticipated in the area of the final highwall or major spoil excesses in the box cut area. This can be determined by reviewing the Operation Plan map (Exhibit 12-2) and pre- and postmining sections presented in the Exhibit 20-4 series, as well as, the pre- and postmining topographic slopes. Surface treatment of graded spoil is discussed in Tab 21. Small depressions are not planned at this time; however, if small depressions are needed to conserve moisture, minimize erosion, create and enhance wildlife habitat or assist revegetation, plans will be submitted for approval prior to construction. Terraces are not planned for Seneca II-W. Proposed permanent impoundments are planned for Seneca II-W and are discussed in Tabs 13 and 17. SCC does not anticipate any grading problems but shall monitor the success of the backfilling and grading program at least annually. This monitoring will include visual inspections of areas graded to determine PR-05 4 Revised 01/06