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• <br /> found to have OM values greater than 17.2 percent. All of the bench <br /> materials were found to have "suitable" OM levels. The two excursions were <br /> associated with the two uppermost coal seams in the overburden where OM <br /> values of 23.1 and 24.4 percent were found. It would appear that these <br /> materials might potentially pose limitations on the revegetation where these <br /> materials are utilized, however, this is not believed to be the case. These <br /> two strata were found to have the highest nitrate nitrogen levels found for <br /> any of the materials sampled. Values of 4.9 and 12.1 mg/N03-N/kg were <br /> associated with these exposed coal seams. This enhancement in plant <br /> available nitrogen can be viewed as very positive with respect to <br /> revegetation and suggests that these carbonaceous materials may not follow <br /> the commonly assumed perception that coal is not a biologically active source <br /> of organic matter. Examination of the root growth in these two coal seams <br /> reveals that they contained a disproportionally greater concentration of <br /> roots than were found in any of the surrounding materials. Since these <br /> carbonaceous materials are documented as having greater nitrate nitrogen <br /> levels, which is very positive with respect to revegetation as well as a <br /> greater rooting density than the surrounding non-carbonaceous materials, it <br /> appears that these materials and possibly the processed coal waste materials <br /> placed into the refuse pile contain positive rather than negative amendment <br /> properties. <br /> The two excursions above the Wyoming DEQ suspect level for OC represent <br /> 1.995 percent of the total potential volume of overburden materials sampled. <br /> Given the fact that no other parameter suspect levels were exceeded, and that <br />• these materials appear to exert positive rather than negative functions to <br />the existing plants growing in this area, no problems are expected with <br /> respect to elevated OM values. It is also important to note that these <br /> carbonaceous zones are thin (1.1 and 2.8 feet thick), and that significant <br /> mixing will occur during salvage, replacement and regrading. The materials <br /> immediately adjacent to these high OM zones contain an average of 2.13 <br /> percent OM meaning that the necessary dilution rate to reduce OM below the <br /> suspect limit is only 33 percent. Given the mixing that will occur and the <br /> positive aspects of these high OM zones as described above, these materials <br /> possess a "suitable" ranking with respect to overburden quality. <br />Rock Fragments. The Wyoming Guidelines report that materials having greater <br />than 35 percent rock fragments are "unsuitable" as topsoil substitute <br />materials. Examination of the existing soils information in the approved <br />permit document reveals that 27 soils pits with notations on rock fragment <br />content were dug in the immediate potential borrow area. These data found <br />on pages 180 to 187, 195, and 206 to 207 of the existing Raton Creek Mine <br />Permit document that in most instances the rock fragment content is quite <br />high, usually between 10 and 50 percent. Six of the 21 holes correlate to <br />the immediate area sampled in this evaluation. Soil pits A1, A3 and A4 <br />contain "channery" textural modifiers meaning that these soils contain <br />between 15 and 35 percent channery rocks. Soil pits 5-6 and A2 contain less <br />than 15 percent rocks as denoted by the absence of textural modifiers in the <br />names. Of the remaining 21 soil pits, Soil Test Area III, pit Y 4, Soil Test <br />Area V, pits A6-A17, and Soil Test Area 1, pits 1-7, correspond to this <br />general area. <br />. Most of the notations regarding rock fragment content in the SCS soil <br />pits relate to the stone and cobble size fractions and as a general rule, <br />gravel content appears to be omitted. this is confirmed by correlating the <br />soils mapped for this area with the soils mapping unit and profile <br />descriptions for soil type PjF Louviers-Rombo-Travessilla Complex, 30 to 65 <br />