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Exhibit 13-2, Reclamation Plan). As of December 31, 1991, there was 492-8 acre-feet of <br />stockpiled soil and 150.7 acre-feet of soil remaining to be salvaged (Table 91.4). By <br />dividing the number of acre-feet available soil (643.5) by the number of acres of projected <br />disturbance (785.4), it is estimated 0.8 feet of suitable soil is available to be replaced. <br />The average thickness of replaced soil is likely to exceed 0.8 feet as the stockpiled soil <br />swells during redistribution. Previous field studies from Seneca II Mine indicate fine <br />sandy Loam, loam, and silty loam textured soil may shrink (compact) from 21 to 28 percent <br />., <br />when s[ockpiLed. The soil replacement depth (0.8 feet), determined from the annual soLl <br />balance, is slightly less than previous projected soil replacement depths <br />determined in July 1984 (1.0 feet), August 1986 (1.0 feet), January 1988 (1.1 feet), April <br />1989 (1.1 feet), April 1990 (1.0 feet), and March 1991 (0.9 feet). <br />Soil Replacement Technique. Soil replacement areas for the 1991 field season are shown on <br />Exhibit 91.2, 1991 Soil and Spoil Xonitoring Map. Historical soil replacement areas for <br />the 1977 through 1990 field seasons are included with two previous Topsoil and Spoil <br />Monitoring Reports and the 1990 Annual Reclamation Report for Seneca II Mine (PCC, 1989; <br />1990; and 1991). Four reclamation blocks totalling 20.8 acres were reclaimed during 1991 <br />• using direct haul topsoil. The soiled areas are identified on Exhibit 91.2. <br />Summary. The soil replacement thickness for the remaining permit terms was projected to be <br />1.0 feet (Permit C-80-005, Tab 9, Attachment 9-4). The balance completed above shows that <br />at least 0.8 feet of soil will be available to be replaced. Peabody suspects the <br />difference between pre-disturbance projected and post disturbance actual soil <br />redistribution thickness is attributed to two important factors. First the density of <br />soil in stockpiles has probably increased and caused an underestimation of soil that is <br />stockpiled. Second, the projected affected lands area decreased in the upper wolf Creek <br />pit. The soils in [his area were fairly deep, ranging from 2.8 to 3.0 feet. The <br />stockpiled soil will swell during redistribution. Peabody will continue to salvage, store, <br />and replace soil as described and approved in Permit C-80-005. Peabody~s soil scientist <br />and reclamation supervisor will continue [o closely monitor soil handling activities at <br />Seneca II, verifying that scraper operators are salvaging all viable soil materials and <br />redistributing soil at the specified thickness. <br />Revegeta[ion. <br />• Revegetation activities in 1991 included permanent revegetation of disturbance areas at the <br />11 <br />1991 ~ft~ <br />