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provides results on the basis of single storm events.The Division's Guideline Regarding Selected <br /> Coal Mine Bond Release Issues dated April 18, 1995 outlines what the Division may use to <br /> evaluate reclaimed lands proposed for Phase II bond release. In summary,the Division may evaluate <br /> the following: <br /> o Topsoil replacement depths <br /> o Vegetation cover success standard <br /> o Species composition <br /> o Re-establishment of essential hydrologic functions on Alluvial Valley Floors (AVF's). <br /> o Erosional features <br /> o Sediment transport <br /> o The condition of sediment ponds and any needed maintenance on ponds receiving runoff <br /> from bond release parcels. <br /> Post Mining Land Use <br /> TMI's objective is to restore the affected areas to the land uses prior to mining as indicated in section <br /> 4.2 of the permit. There are three significant land uses within the permit boundary: farming, grazing <br /> of domestic livestock and use by wildlife. The bond release block does not contain farmland and thus <br /> will be used as rangeland for livestock and wildlife. The reclaimed lands have vegetative cover <br /> composed of a variety of grasses, forbs, and woody shrubs as described in the above sections. The <br /> species, seasonality and forage characteristics of the reclaimed vegetation are suitable for the approved <br /> post-mining land uses. The Division has observed livestock grazing and substantial wildlife use of <br /> previously reclaimed areas. The revegetation success standards were based on what would be <br /> necessary for the land to properly function to accommodate the post mine land uses. Based on the <br /> achievement of these requirements, the Division rinds that the revegetation on the Trapper Mine <br /> reclaimed areas is capable of supporting post- mining land use. <br /> Sedimentology <br /> The condition of the sediment ponds and any needed maintenance on the ponds receiving runoff from <br /> the bond release parcels were evaluated. Ponds receiving run-off from the bond release parcels are <br /> also receiving flow from affected lands not under consideration for bond release at this time. <br /> In accordance with Rule 3.03.1(3)(b) and with Section IILA.7.a. of the Division's 1995 Guideline <br /> Regarding Selected Coal Mine Bond Release Issues,Trapper submitted two evaluations to demonstrate <br /> that runoff from each bond release block will result in equivalent or lesser sediment contribution as <br /> compared to baseline conditions and similar undisturbed lands. <br /> Trapper's bond release application compares pre and postmining sediment yields by calculating <br /> expected sediment yields for both conditions. Trapper used the USLE(Universal Soil Loss Equation), <br /> and SEDCAD 4 for Windows calculation methods. The USLE calculates expected average annual <br /> soil loss per acre of land (rate of erosion), based on slope, rainfall pattern, soil type and vegetation <br /> type. SEDCAD 4 calculates the expected settleable solids concentration in runoff from a precipitation <br /> event. Trapper's two sets of pre-mining and post-mining sediment control demonstration models <br /> comprise Appendix 3 (SEDCAD 4), and Section 1.4 (USLE), of the bond release application. <br /> USLE Comparison: Only the "C" factor and the Curve Number varies between the pre-mining and <br /> the post-mining calculations; all other variables are constant for pre-and post-mining. The C factor <br /> Permit Number C1981010 <br /> SL22 Page 11 of 18 <br />