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ExhibitE <br />Final closure reclamation will be performed after all mining has been completed. When final facility <br />• closure is undertaken, the plant and other structural improvements will be dismantled and sold or buried <br />on the site. Pavement and concrete floors and foundations will be removed and either buried on-site or <br />recycled as construction aggregate off-site. The railroad spur will be reclaimed by the removal of the <br />track and ballast. The resulting corridor will be graded to blend with surrounding topography before <br />topsoil is placed over the area. The access road and St. Charles River Bridge will be left in place at the <br />request of and for the benefit of landowners. <br />Pit walls will be dozed to blend with the surrounding topography. Graded slopes will be no steeper than <br />4H:1 V, and main drainages within the reclaimed areas will be re-established. Pit walls at the northern <br />edge and the sides of the access ramp will be permanently stabilized by placing a mixture of spoil and soil <br />materials on the final slopes. The spoil/soil mixture's content will be 70 percent or less for rock, and 30 <br />percent or more for soil. Final pit walls will be sloped not to exceed 4H: IV. The graded backfill will be <br />ripped with equipment and implements capable of penetrating a minimum of 12-inches deep on 18-inch <br />centers to alleviate compaction and reduce slippage planes at the interface between the backfill and soil. <br />Once grading is completed, topsoil and subsoil materials will be spread followed by seeding, fertilizing, <br />and mulching operations, when conducted. Exhibit D-1 illustrates topography at the end of the first eight <br />years of mining operations. Exhibit D-2 illustrates the sequence and status of reclamation activities at the <br />end of the first eight years of operation. <br />Final Reclamation Material Balance <br />Exhibit F-1 is the final reclamation surface plan for the quarry area at the end of the 50-year operating pit <br />life. Using the Surpac Vision mine modeling software, an ultimate pit shell for the entire 50-year life of <br />mine was developed that incorporated the proposed side slopes in both overburden and limestone. The pit <br />floor was defined by extracting 5-feet of the Codell Sandstone. With this pit shell and pre-existing <br />topography, a surface-to-surface volume extraction was performed to determine the total bank volume of <br />available reclamation fill. The approximate bank volume of overburden (unconsolidated material and <br />shale) is estimated to be 14.4 million cubic yards. <br />In order to define the final reclamation surface, a 20 percent swell factor was used to calculate the overall <br />volume of material that is anticipated to be placed back into the quarried area over the course of mining. <br />Using this swell factor, the approximate quantity of available reclamation backfill becomes 17.3 million <br />cubic yards. Generalized balanced cross sections depicting the pre-mining topography, ultimate pit shell <br />and reclaimed surface are provided in Exhibit F-2. Although the quantity of material backfilled will vary <br />spatially, the mining and reclamation process is expected to result generally in a fill wedge increasing in <br />thickness to the southeast. Based on this scenario, a final reclamation surface was modeled given the <br />volume of backfill available. Once complete, the contours were generated from the reclamation surface <br />model and incorporated into the surrounding topography, as shown on Exhibit F-1. <br />Restoration of Arroyos <br />Several arroyos were assessed to determine that cross-sections reflect a broad, shallow area, typical in the <br />upper watersheds. From these assessments, a typical cross section was identified having a trapezoidal <br />shape with a 5-foot bottom and nearly flat slopes (that is, 20h:1v). This cross section will convey the 100- <br />year flood with depths no greater than 3 feet, which reduces flow velocities, shear stresses, and therefore <br />erosive forces. Depending on flow velocity, erosion control measures vary from vegetation for flat slopes <br />(up to 0.5%), to vegetation and rock for intermediate slopes (from 0.5% to 2.0%), and vegetation and turf <br />reinforcement mat for higher slopes. Specifications for the reconstructed arroyos are in Appendix F <br />"Surface Water Management Plan." This approach will provide an erosion resistant channel not <br />1180-Mine Permit Exhibits (Jul.05.02)FINAL.doc E-2 <br />July 8, 2002