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than 3:1. The highwall reduction area and spoil material will be worked together to shape and blend the • <br />material into the natural topography, creating a transition that prevents drainage from creating knickpoints, <br />propagating natural undisturbed slopes, and enhancing the postmining land use. <br />Thin or thick overburden as defined by Section 4.14.4 and 4.14.5 does not exist at Seneca II-W. The final <br />volume is greater than 0.8 of the initial volume, therefore the thin overburden criteria is not applicable. <br />The thick overburden rule does not apply because the final volume is not greater than 1.2 of the initial <br />volume. Please refer to Page 5 for the volume calculations. <br />Spoil material will be temporarily stored away from the immediate vicinity of the initial pit as shown on <br />Exhibits 12-2 and 12-3. This will allow the mining operation to proceed without being hampered by <br />rehandling of the spoil material. The spoil will be stored in an area that is convenient for final placement in <br />the open pit either by dozing or short hauling with scrapers. All salvageable topsoil will be removed from <br />the temporary overburden stockpile areas according to the approved plan before any spoil material is <br />placed. If the existing ground is steeper than 20% it will be keyed in a manner that increases the stability <br />of the fill. The keyway will be a minimum of 20 feet in width and 1 foot in depth. The keyway will begin <br />at the toe of the fill. The overburden material will b placed in horizontal lifts starting at the toe of the <br />stockpile area. The fill slope of the spoil material shall be 2H:1 V or flatter. This slope is flatter than the <br />angle of repose of the spoil material. During and after construction of the stockpile, runoff from upland • <br />areas will be prevented from ponding on or saturating the stockpile. Although ditches or berms to control <br />upland runoff are no[ anticipated, designs for these type of structures will be submitted for approval should <br />they become necessary. The stockpiles will be stabilized by seeding with the approved temporary <br />reclamation seed mix. <br />Box cut spoil will initially be placed onto unmined land as described in Tab 12. This material will be <br />rehandled when the dragline returns to the box cut areals). Portions of box cut spoil will be temporarily <br />stored in approved locations above the highwall for backfill into portions of the final pits. All vegetative <br />and organic material and topsoil will be removed from the ,area where box cut spoil is placed, and the spoil <br />graded both into the mined area and blended into the surrounding terrain. ~NO material shortages or <br />excessive disturbed areas are anticipated in the area of the final highwall or major spoil excesses in the box <br />cut area. This can be determined by reviewing the Mine Plan Maps (Exhibits 12-2 and 12-31 and pre- and <br />postmining cross sections presented as Exhibits 20-4series as well as the pre- and postmining topographic <br />slopes. <br />u <br />2 Revised 9/98 <br />