2010-05-07_PERMIT FILE - C2009087 (8)

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RULE 2 - PERMITS The Binco clay and the Aaberg silty clay are generally associated with the moderately to steeply • sloping (10 -60 percent) areas in the southwest and west end of the proposed PSCM disturbance area. Inclusions of other soil types occur within the primary soil units, although their aerial extent and significance are minor. Table 2.04.9 -T2, contains the acreages of each soil map unit within the PSCM surface disturbance area. Previous Soil Surveys A number of additional soil surveys have been conducted over the life of the current and historic mining activities within the PSCM permit boundary and surrounding area. Mining operations at the Seneca II Mine in the PSCM permit area were initiated in the 1970s, prior to permanent program regulatory requirements. Therefore, soil materials from some of these mined areas were not sampled, characterized, salvaged, or segregated. As required under various regulatory programs, several of these previously disturbed areas have, however, been evaluated relative to soil conditions and some have been sampled for soils analyses in previous area soil surveys (1980 and 1983 supplemental sampling programs). Historical soil surveys within the PSCM permit boundary include the Foidel Creek Mine baseline soil survey (Twentymile Coal Company, 1999). This soil survey was completed for the areas to be disturbed by the Foidel Creek Mine during 1999. This soil survey includes a portion of a transportation corridor study area. The Seneca II Mine soil survey, prepared for the area to be disturbed in the Seneca II Mine permit boundary, was completed in the early 1980's and periodically updated with a final revision as late as December, 1997 (Seneca Coal Company, 1997). This area falls within the boundaries of the potential surface disturbance boundary of the PSCM. In • addition, a soil survey conducted at the Seneca II Mine on reclaimed mine lands was summarized in a report entitled 2001 Soil Sampling, Seneca II Mine and Seneca II -W Mine (IRI, 2001). The information derived from this latest soil survey is used to describe reclaimed soils to be salvaged for future reclamation of the proposed PSCM disturbances. The 2001 Seneca II Mine soil survey sampled 10 sites in the southern and western portions of the mine area representing reconstructed soil conditions found on reclaimed lands in the PSCM surface disturbance area. The same sample pits were sampled for subsoil /spoil from the bottom of the topsoil horizon to the top of spoil material. Representative topsoil results, reconstructed soils at the Seneca II Mine: Depth - The average depth of soil is 11.5 inches (.9 feet). Depth of soil ranges from 10 to 20 inches (.8 to 1.6 feet). The soil in both sample pits consisted of two horizons. The upper horizon averages five inches of thickness and ranges in depth from zero to five inches in thickness. The lower soil horizon averages 6.5 inches in thickness and ranges from five to 11 inches in thickness. The difference in horizons is due to structure and dry and moist consistence as the result of disking. All other characteristics between horizons are the same. Textures - Textures are loams, clay loams and clay. Clay content averages 25 percent and ranges 14 to 34 percent, sand content averages 34 percent and ranges 26 to 39 percent. Silt content averages 41 percent and ranges 36 to 45 percent. • Rock Fragments - Rock fragments average five percent and ranges from zero to 10 percent. Rock fragments are predominantly gravel size (2mm to 75mm) of sedimentary origin, primarily sandstone. PSCM Permit App. 2.04 -123 6/15/09