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6. This value for selenium was chosen based on guidance from Dave Dearstyne of NRCS <br />and recent data that other states are using. Dave is currently working extensively (2008) <br />with the Selenium Task Force on the western slope and is very knowledgeable about this <br />issue. He basically stated that there is no concern for selenium unless Mancos shale <br />strata are being placed near the surface. At the proposed NHN Mine, no Mancos shale <br />has been encountered in the overburden. Also, all tests of water soluble selenium in the <br />pre -mine soil survey of NHN Mine show all values less than 0.1 ppm. Dave Dearstyne <br />believes a threshold suitability level of 0.2 ppm in the topsoil material and 1.0 ppm in the <br />subsoil material is adequate. These are the levels proposed. <br />These suitability evaluations, based on averages across the study area, were used for <br />topsoil volume determinations shown on Map 2.04.9 -3, New Horizon North Mine — <br />Topsoil Salvage Map. The number of profiles on which these averages are based is noted <br />in the Soil Profile descriptions range of characteristics. The recommended topsoil <br />salvage depths for each map unit are weighted averages of each major component of the <br />map unit, (those listed in the map unit name - for both associations and complexes) as <br />well as major soil inclusions, are presented on Map 2.04.9 -3, New Horizon North Mine — <br />Topsoil Salvage Map. <br />Topsoil Salvage Depths <br />This discussion addresses the extent of and volume of salvageable topsoil in the proposed <br />NHN Mine Permit Area as shown on Map 2.04.9 -3, New Horizon North Mine — Topsoil <br />Salvage Map, which contains an estimated soil disturbance area of 280.83 acres. WFC <br />commissioned a topsoil balance study for the proposed permit boundary. The study <br />included the entire NHN Mine Permit area. This topsoil salvage study can be seen in Map <br />2.04.9 -3, New Horizon North Mine — Topsoil Salvage Map. This map shows the extent <br />of topsoil which is suitable for topsoil salvage for each respective soil mapping unit as <br />well as the volume of material which is available. <br />Section 2.05.4(2)(d) Page 12 January 2012 <br />