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1.4.1 Rearadina <br />Regrading would be the initial reclamation activity conducted at a mine if the operator permanently ceased <br />operations. The areas requiring regrade at Trapper Mine, if this improbable event occurred, would be the <br />open pits and associated spoil piles, roadways, impoundments, and ash disposal area. Regrade costs are <br />summarized in Table 1.4-2. Supporting calculations are shown in Tables 1.4-3 to 1.4-7. <br />1.4.1.1 Pit Rearadina <br />The pit regrading costs for Trapper Mine include the current ash disposal area, active pits, the old G test <br />and G strike pits, and the final cut where Derringer and Enfield pits come together. The final cut in D and <br />E pits has been permitted as an ash disposal area. Far reclamation liability purposes, it is assumed that <br />there is no ash in the D!E ash disposal area. <br />Conceptually, the backfilling of the open pits would be accomplished by blasting and reducing highwalls <br />and by using spoils from previous cuts. The cross sections used to calculate the volumes shown for all <br />pits in the regrade tables are included in Appendix A. The spoil diagrams that are the basis of the regrade <br />sections were developed using Mincom software and are a relatively accurate depiction of pit geometry <br />before regrade. The cross sectional areas were applied to incremental pit lengths for the worst case year <br />of 2006. The number of cross sections constructed for each pit depended upon the total pit length and the <br />variability of overburden and interburden depths to a linear change in depth. <br />1-33 <br />~~lS~rD <br />;R~pG <br />