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• 1.4.1 Reoredina Regrading would be the inRial reGamation activity conducted at a mine if the operator permanently ceased operations. The areas requiring regrede al Trapper Mine, 'rf this improbable event occurted, would be the open pRs and associated spoil piles, roadways, impoundments, and ash disposal area. Regrede costs are summarized in Table 1.42 while the calculations of time required to complete regrading activities are shown in Tables 1.4-3 to 1.4~. 1.4.1.1 PR Regradino The regrading costs for Trapper Mining Inc.'s ash disposal area, alive pits, and the final cut where Dertinger and Fltfleld pits come together, would require the largest e~endRure of money as can be seen from the tabulated dollar values. The cross sections used to calculate the volumes shown in these tables are inGuded in Append'a A. The spoil diagrems that are the basis of the regrede sections were devebped using Mincom software and are a relativey accurate depiction of pit geometry before regrede. The cross sedlonal areas were applied to incremental pit lengths for the worst case year of 2002 in the ca~ulation of regrade volumes (or each pit. The number of cross sections constructed for each pk depended upon the trial pit length and the variabil'rly of overburden and interburden depths to a linear change in depth. • Conceptualy, the backfilling of the open pits and elimination of highwalls would be accomplished by using spoils from either one or two of the previous cuts plus the spoils from the curtest cut for a total of two or three spoil rows. The number of spoil rows required would depend upon the pit. ft is important to note that this regrede work would also resuM in the final coMOUring of all ungraded spoils rows for each pit since mine regrede reGamation adivkies will always be within this spoil row limit (refer to Section 3.5). J~•J I~'~ ~~I~i'.V • _IJ -: -- dIDN i ~ ~9~a--