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Susan Burgmaier, DRMS April 11, 2013 TR77; Review Memo Phosphorus, Potassium and Nitrogen The 2003 topsoil samples yielded an average nitrate content of 10.15ppm, the coverfill material yielded an average nitrate content of 3.98ppm. The topsoil samples yielded an average Phosphorous content of 2.76ppm, the coverfill material yielded an average Phosphorous content of 4.85ppm. The topsoil samples yielded an average Potassium content of 170ppm, the coverfill material yielded an average Potassium content of 241ppm. The coverfill has a lower nitrate content but a higher phosphorous and potassium content than the topsoil samples. Given this, there is a difference in these nutrient contents of the two soil materials. A lower nitrate amount in the coverfill material may actually help limit the amount of annual species that will establish in these areas where this material is applied. In general it appears the soils in this area are very low in nutrients except for Potassium given the small amount of A horizon and organic matter found in the soils. Colorado State University Extension Fact Sheet No .536, "Fertilizing Revegetated Disturbed Lands" provides several tables with suggested broadcast fertilization rates for Nitrogen, Phosphorous and Potassium based on the amount of these nutrients measured in the soil. For Nitrogen (Nitrate), given the levels found in both the topsoil and the coverfill material, both soils would require the same level of fertilizer to be applied. For Phosphorous, both soil materials would require the application of a fertilizer. However, the coverfill material would require less phosphorous amendment. Neither soil material would require a Potassium fertilizer. The coverfill material is of comparable quality to the topsoil in terms of Nitrogen, Phosphorous and Potassium content. Given the lab results both material may require a fertilizer amendment when it is utilized for reclamation. Page 2.05 -79 of the permit discusses BRL soil test plan to determine if soil amendments are needed for the topsoil that has been replaced on the reclaimed lands. Given this, the Operator has a plan in place to evaluate the soil medium and amend it accordingly. The coverfill material should be treated with the same approach. Texture Class The texture class percentages found in the coverfill material is different on average for the Sand and Silt texture class than the topsoil. The average percent of the clay is almost the same between the two soils. The average percentage of Sand found in the topsoil and coverfill material samples are 17.71% and 43.33% respectively. The average percentage of Silt found in the topsoil and coverfill material samples are 53.29% and 29.67% respectively. The average percentage of clay found in the topsoil and coverfill material samples are 28% and 27% respectively. However, the dominant texture classification for the coverfill material was found to be clay loam which naturally occurs in the NRCS soil unit for the gob pile #2/4 area; unit 74 - Torriorthents- haplargids complex. Electrical Conductivity The electrical conductivity (EC) measure of the 2003 topsoil samples and the coverfill material was found to be on average .91 dS /m and 2.17 dS /m respectively. The topsoil samples are not saline and the coverfill material could be considered only slightly saline and will not significantly impact the development of the plant species to be used to reclaim the site. Table 2 on page 73 in the 1998, "Native Plant Revegetation Guide for Colorado " produced by the Colorado Department of Natural Resources, provides accepted criteria to judge suitability of topsoil in an upland community based on pH, EC, Texture, Sodium Adsorption Ratio (SAR) and % Organic matter. According to this table, both soil materials fall under the category of suitable and good. Sodium Adsorption Ratio The Sodium Adsorption Ratio (SAR) of the 2003 topsoil samples and the coverfill material samples were found to be on average 4.83 and 2.36 respectively. The average SAR value of the coverfill material is less than the topsoil samples. However, for the topsoil material, sample no. 7 yielded a much higher SAR value than any other sample and may have skewed the average SAR value for the 2003 topsoil samples. Table 2 on page 73 in the 1998, "Native