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SeYiar - 2.04.9 <br />disturbance areas (west bench area) and that the undifferentiated surface and subsurface materials in <br />• the other disturbance areas generally meet revegetation suitability criteria and can be reclaimed with <br />the addition of approximately 6inches of suitable topsoil material. Recogntztng that soil material <br />availability is a concern, OMI has committed to recover all reasonably available and recoverable soil <br />resources from new mine disturbance azeas (up to a maximum depth of four feet) and to sample and <br />test replaced soils for suitabilitypriorto revegetation. <br />Based on soil evaluations and analyses, the Absarokee-Work loam and Beenom-Absazokee association <br />aze recoverable throughout their respective soil profiles except where constrained by the presence of <br />clay materials or topographic limitations. Similarly the Tomorthenrs-Haplargids complex u generally <br />recoverable throughout its profile except where constrained by depth variability, clay materiak, <br />topographic limitations, or most significantly surface rocks and boulders and high rock content. Of <br />the Four soil types that have been or will potentially be disturbed, the Tomorthents-Rock outcrop, <br />sandstone complex is the most limited relative to potential soil recovery and availability Limitations <br />on recoverability of Torriorthents-Rock outcrop, sandstone complex soils include clay content, depth <br />variability, high stone content, possible selenium concerns for the subsoik, and most significantly <br />topographic limitatioru and operational constraints associated with extensive exposures of rcek <br />outcrops and numerous large rocks and bouldea on the surface. <br />Consistent with and as a reflection of limited soil development, soil sampling and analyses indicate <br />very little difference between surface and subsurface materials for the soil types evaluated. The only <br />potential material suitabiliryconstraints identified (based on Wyoming Department of Environmental <br />Quality Guideline No. 1 for Topsoil and Cwerburden in the absence of Colorado guidelines) were <br />boron (Samples HG1, HG2, BG1, BG2, BG3, BG4, E6-1, ECS-2, and EG1 through EG9), <br />selenium (Samples EG10B, EG11E, and EG11F), and clay (Samples BG3, ECS-1, ECS-2, EG1, <br />EG4, EGS, EG8, EG9, EG10A through EG10F, EG11A through EG11F, EG12A, and EG <br />• 12B). <br />The elevated boron values are For samples that were prepared using acid digestion of the samples and <br />then analyzed. The resulting total boron concentrations indicated are several orders of magnirude <br />higher than typical values for the normal analyse method, are not coruistent with boron values for <br />other soil samples analyzed using the nom~al analysis method, and should not be coasidered as <br />representative of actual soil suitability relative to boron content. <br />The three samples having elevated selenium values were minimally above the suitability threshold for <br />selenium of 0.1 ppm (i.e. 0.18, 0.115, and 0.18) and represent only 7.5 percent of the 40 samples <br />analyzed. While these samples represent a potential concern that will be evaluated through sampling <br />of the replaced soil materials the concern does not appeaz to be significant based on the available <br />sampling data. <br />C]ay texture appears to be a more prevalent concern based on the number of samples showing the <br />characteristic for the sampled soik. It should be noted that for some of the earlier samples (1980 Pm <br />Law Disturbance Sampling Program) the textural classification was based on visual characterization <br />rather than actual particle size analysis, however, clay texture does appeaz to be a limiting constraint <br />which may affect soil recovery and u taken into consideration in OMI's reclamation plans. <br />r 1 <br />PR04 2.04-91 Revised August 2000 <br />