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• 1 4.1.3 Impoundment Recradino <br />Calculation of regrade times for existing and future impoundments is shown in Table 1.4~. Impound- <br />ment volume calculations are shown in Table A3 of Appendix A. Many of the impoundments were <br />assumed to be permanent structures. As a result, they were left in place. Impoundments requiring <br />reclamation include Far East Buzzard, Coyote, Middle Pyeari, Sage, West Horse and Deal. <br />The earthen impoundments would be graded with dozers, filling back the areas from which the material <br />had been previously removed. Caterpillar D10R dozers with asemi-u blade were used to develop cost <br />data and productivity. This regrading would establish the approximate original contours in the affected <br />areas. <br />1 4.2 Retopsoilinu <br />After regrading, topsoil from permanent stockpiles would be placed on all disturbed areas except for such <br />minor disturbances as light tluty access roads where topsoil was never removed. Topsoil replacement <br />costs are summarized in Table 1.4-8 while Table 1.4-9 summarizes re-topsoil quantities and time. <br />Productivity and cost values were those of Caterpillar 637E scrapers. This equipment type and particular <br />model was selected as a cost efficient means of loading, transporting, and uniformly spreading the top- <br />• soil. TALPAC software was used to determine scraper production per hour. The capacity used for each <br />scraper load was 25 bank cubic yards. As a result a 16% swell is implied since the actual average <br />capacity for a CAT 637G is 29 loose cubic yards (24 cyds struck capacity, 34 cyds heaped capacity) <br />The areas requiring topsoil replacement would include all active, inactive and abandoned pits and their <br />associated roadways, impoundments, and the industrial complex area. <br />Map M10B illustrates topsoil removal and replacement activities for each year of the permit term, <br />including the worst case year of 2006. This map is the basis for pit disturbance areas. The industrial <br />complex area and other topsoil replacement areas were calculated from mine workings maps. <br />• <br />1-41 <br />- ~-~.. <br />