2014-04-03_REVISION - C1982057 (4)

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and statistics of the sampling effort, while Exhibit C, Topsoil Sample Map, shows locations of the topsoil sample sites and the topsoil depth at that location. The documentation for this sampling effort is presented in the Annual Reclamation Reports submitted to CDRMS beginning in the 1990s. Revegetation Success Rule 3.03.1(2)(b) specifies that Phase II bond release may be granted when when establishment of vegetation to support the postmining land use is demonstrated by meeting the approved success standard for cover. Further, the CDRMS Guideline Regarding Selected Coal Mine Bond Release Issues (April 18, 1995) further specifies that species composition be evaluated. The following sections and attached Revegetation Supporting Information in Attachment E detail the required demonstrations. Cover Vegetation establishment will be considered acceptable if the cover of the revegetated area is at least 90 percent of the cover from the reference area or other standard with 90 percent statistical confidence (Rule 4.15.8). Phase II bond release is being requested for 805.1 acres at the II -W mine. These lands have established vegetation that is at least two years old and are able to support the approved post - mining land use. Phase II revegetation success evaluations were based on the success standards described in Tab 22 of the II -W mine permit and the above referenced rules and guideline. Establishment of vegetation is demonstrated by meeting the appropriate cover success standard based on statistically adequate sampling. Species composition and representation of the species to meet final diversity requirements is addressed by the vegetation cover data and species diversity evaluations included in Tab 22. The cover success standard and evaluation for success at the II -W Mine is as follows. The cover success standard is based on a weighted average determination based on the five pre -mine vegetation type contributions to total acreage. The all hit herbaceous cover standard (adjusted for annuals and noxious weeds) is derived from sampling in the following five pre -mine types in the extended reference area weighted by premine acreage contribution: 11% Aspen, 34.5% Mountain Brush, 31.3% Sagebrush, 12.8% Steep Mountain Brush, and 10.4% Western Wheatgrass /Alkali Sagebrush. Greater than 30 samples were taken in the bond release area to allow for hypothesis testing using the reverse null hypothesis. Sample adequacy based on all -hit values was calculated for the bond release area and achieved for each of the reference areas. Calculation of the 90 percent of the cover standard for the 2009 sampling is demonstrated below. Cover standard derivation: Aspen Reference Area Allowable All -Hit Herbaceous Covert = 76.5% Mountain Brush Reference Area Allowable All -Hit Herbaceous Covert = 35.9% Sagebrush Reference Area Allowable All -Hit Herbaceous Cover' = 29.2% SL -5 -6