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and 4 (2.9 feet) would produce a suitable alkaline spoil (see Section 2.04.6, Table 2.04.6 -10). <br />Partial mixing of alkaline and acidic materials is anticipated during cast blasting, dozer pushing, <br />and shovel /truck handling due to the thinness of Units 2 and 4 and the stratification of alkaline <br />and acidic strata. Normal overburden /interburden handling operations may also effectively bury <br />the acid - forming strata. <br />Typical overburden /interburden handling operations are described in Section 2.05.3, Operation <br />Plan and Section 2.05.4(2)(c), Backfilling and Grading. <br />Once topsoil is removed, soft upper overburden (Bench 1 or Unit 1 material) is normally <br />removed by the truck - shovel fleet and taken to the back of the previous pit for backfilling using <br />the same temporary road around the end of the pit. A significant amount of this Bench 1 <br />material is normally placed immediately below the Lift A Topsoil, Lift B Topsoil or Mixed topsoil <br />in all areas. The amount varies per area, however, the total amount of combined topsoil and <br />Bench 1 Subsoil Substitute will be approximate 4 feet thick, except in the WFC property on the <br />west side of the permit, as described earlier, which will be at least 3.5 feet thick. The Bench 1 <br />material thickness does decrease going westward and WFC will attempt to utilize all the <br />suitable Bench 1 to get the required thicknesses specified above. <br />Lower overburden (Bench 2) is usually cast blasted, dozed and loaded /hauled with <br />shovel /trucks and placed in the previous mined out pit for backfilling purposes. As the <br />overburden trucks dump off the backfill spoil dump, large dozer(s) will final grade the truck <br />dump area into the final pre topsoiled contours. <br />The regraded spoil will be mechanically loosened and mixed by ripping, chiseling, or approved <br />alternate forms of scarification. The major advantages of scarification are related to the <br />physical properties of the spoil. The topsoil and spoil are scarified to decrease compaction, <br />increase aeration and water movement, and increase plant rooting depths. Increased water <br />movement may, to some degree, allow more downward leaching of carbonates. Therefore, <br />although the greatest benefits of scarifying are related to the physical soil properties (density, <br />Revised PR 06 June 10 2.05.4(2)(d) -3 <br />