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

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RULE 2 - PERMITS surface - affected areas were fully described and sampled at representative sites a minimum of one time • each. A total of 30 soil samples were collected from the six sample sites. However, based on revisions to the potential PSCM surface disturbance area boundary only two full soil pedons (Binco clay and Aaberg silty clay) were sampled for laboratory analysis in soil series matching map units within the PSCM disturbance boundaries. These two soil profiles were sampled and analyzed to evaluate soil physical and chemical properties and suitability relative to salvage and use as a revegetation medium. Soil sample designations, sampling areas, and mapping unit correlations are summarized on Table 2.04.9 -T3, and sample locations are shown on Map 2.04.9 -M2, Order I Soils Survey — Surface Disturbance Area. Analytical results for the remainder of the pedons sampled are presented in the Soil Resource Survey of the Peabody Sage Creek Coal Mine, Routt County, Colorado (Exhibit 2.04.9 -E1, Soils Information). The following are the map unit descriptions for the Binco clay and the Aaberg silty clay as presented in the PSCM Soil Resource Survey: Mau Unit 1OD: Binco clay, 10 to 20 percent slopes Binco was recently re- correlated to the Impass soil series but the Binco name is retained for potential surface - affected areas within the permit area because it is part of both the Seneca II Mine and Foidel Creek Mine soil legends. The Impass name is used for non - affected areas. Binco is an established soil series of small extent mapped in the mountainous areas of north- central Colorado, and is classified as a "Fine, smectitic frigid Chromic Udic Haplustert". Diagnostic features for the typical pedon include a "Bss" horizon ( "B" horizon with slickensides) from four to 23 inches in • depth. The most recent official NRCS soil series description for Binco, dated March 1999, is on file. Impass is essentially the same soil as Binco except it is considered to have an "ustic" soil moisture regime with 18 to 26 inches of average annual precipitation rather than about 12 inches for Binco. Impass is classified as a "Fine, smectitic Chromic Haplocryert". Binco Typical Sample "CC -1" Site and Profile Description: Binco clay was fully described and sampled at one representative site, CC -1, located in a portion of the SW1 /4 of the SW1 /4 of Section 13, TSN, R87W. The sample site is on an upland ridge sideslope with big sagebrush and mixed grass vegetation, and is within the previous potential transportation corridor in the hilly ridge "gap" area between the south end of the Seneca II Mine permit area and the north end of Foidel Creek Mine permit area. Sample site CC -1 has a 12 percent slope, south aspect, slopewash alluvium over residuum from clay shale; and stable surface with no erosion in the vicinity of the sample site location. An evaluation of soil suitability indicates the sampled Binco pedon CC -1 is consistent with the previous Seneca II Mine recommended topsoil salvage depth of six to eight inches, with an average recommended depth of seven inches. Clay content is too high ( >40 percent) below seven inches for salvage. A horizon — Zero to four inches; brown (10YR 5/3) loam, dark brown (10YR 4/3) moist; moderate medium granular structure; slightly hard, friable, sticky and slightly plastic consistence; common medium, fine, and very fine, and few coarse roots; slightly effervescent; from lab data. pH =6.1 (slightly acid), EC=0.4 (nonsaline), SAR =0.4 (nonsodic), OM =13.7 percent by weight -loss on ignition; gradual smooth boundary. r1 U PSCM Permit App. 2.04 -126 6/15/09