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• Nitrate-Nitrogen (N03-N). The Wyoming Guidelines contain no ranking for N03- <br />N with respect to suitability as rooting zone materials but overburden <br />aquifer materials are defined as having an "unsuitable' ranking when the N03- <br />N values are greater than 50 ppm. The N03-N values for the Raton Creek Mine <br />overburden and bench materials were found to range from a low of 0.2 to a <br />high of 12.1 with a weighted mean value of 0.76 mg/kg. These data suggest <br />that all of these materials possess a "suitable" ranking as potential aquifer <br />materials with respect to N03-N values. <br />Molybdenum (No). The Wyoming Guidelines define "suitable" overburden <br />materials as potential rooting zone materials when the Mo values are less <br />than 1 ppm. All of the Mo values for the 24 Raton Creek Mine overburden and <br />bench samples were less than 1 ppm, suggesting that all of these materials <br />possess a "suitable" quality with respect to Mo content as overburden <br />materials. <br />Acid Base Potential (ABP). In the present evaluation ABP was calculated <br />based on the percent pyrite in the materials. Justification for this <br />calculation was based upon the finding that the carbonaceous zone associated <br />with the exposed coal materials still had 100 percent of their total sulfur <br />associated with the organic fraction. Since these organic sulfur forms have <br />not oxidized within geologic time, or have oxidized and are bound in the <br />organic fraction, it is safe to assume that organic sulfur will not <br />contribute to the processes of acidification during the reclamation process. <br />• Furthermore, several of the overburden samples contain upwards to 50 percent <br />of their total sulfur fraction in the pyrite form, meaning that these pyrite <br />forms are not reactive. Since essentially none of the organic sulfur and <br />upwards of half of the pyritic sulfur present in these materials has not <br />oxidized over geologic time, the calculation of the ABP using only pyritic <br />sulfur grossly overestimates the acid producing potential of these materials. <br />The Wyoming Guidelines rank overburden materials as having a "suitable" <br />potential as rooting zone materials when the ABP values are greater than a <br />negative 5 tons of CaC03/1000 tons of material. The range in ABP values for <br />the Raton Creek Mine overburden and bench materials was between a low of 1.4 <br />and a high of 47.0 with a weighted mean value of 12.38 tons of CaC03/1000 <br />tons of material, meaning that all of these materials possess a "suitable" <br />quality as overburden material with respect to ABP. These values suggest <br />that these materials will not turn acidic over time and have significantly <br />high levels of CaC03 to offset any potential acidification that might occur. <br />Arsenic (As). The Wyoming Guidelines rank overburden as being of "suitable" <br />quality when the As values are less than or equal to 2.0 ppm. The As values <br />for the Raton Creek Mine overburden and bench materials were found to range <br />from a low of < 0.01 to a high of 0.29 with a weighted mean value of 0.014 <br />mg/kg, suggesting that all of these materials possess a "suitable" quality <br />as overburden rooting zone material. Since the maximum As value is <br />significantly less than the potential suspect level, it appears that these <br />materials will not affect plant response or water quality over time. <br />. Organic Carbon (OC). The Wyoming Guidelines rank overburden as being of <br />"suitable" quality when the OC values are less than 10 percent or 17.2 <br />percent organic matter (OM). The 24 Raton Creek Mine overburden and bench <br />samples were found to range from a low of 0.3 to a high of 24.4 with a <br />weighted mean value of 1.21 percent OM. Two of the 24 observations were <br />5 <br />