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application document. The supporting basis for an alternative approach to establishing the <br />first -hit herbaceous cover standard is presented in Attachment H of the PSCM SL -01 bond <br />release application document. Vegetative cover was sampled during July and August of <br />2010 for BRB -4. Demonstration of vegetation cover success for BRB -4 requires statistically <br />adequate sampling and comparison to a reference area standard, with hypothesis testing if <br />necessary to demonstrate that reclaimed block herbaceous cover is not less than 90% of the <br />reference area standard (weighted based on 83% original extent of the mountain brush <br />reference area and 17% original extent of the sagebrush reference area) (Permit Exhibit <br />2.05.4 -E1, page 13- 13 -6). For the Phase II bond release block, all -hit cover is sampled and <br />the first -hit herbaceous cover value is derived. The allowable first -hit herbaceous cover is <br />determined by adjusting for woody plants, noxious weeds and excessive annual /biannual <br />cover. <br />Results of vegetation sampling indicated that all of BRB -4 and the two reference areas <br />exceeded the first -hit herbaceous cover standard. The BRB sampling at thirty locations <br />resulted in cover data that exceeded 90% of the cover standard of 36.2% allowable cover. <br />The figure for allowable cover in the BRB -4 of 37.5% is the result of subtracting tree, shrub <br />and non - herbaceous cover, perennial noxious weed cover, and excess annual /biannual cover <br />from the observed first -hit total vegetation cover of 39.6 %. <br />Although the allowable first -hit herbaceous cover sample adequacy was achieved for the <br />BRB -4 and the sage brush reference area, the sample adequacy using the allowable first -hit <br />cover was not met at the mountain brush reference area. The lack of sample adequacy for the <br />mountain brush reference area necessitated utilizing an alternative approach to achieve <br />adequacy. In the development of the alternative approach, it was determined that the true <br />mean (within 90% confidence) for the mountain brush reference area lies between 10.48 and <br />15.12 percent cover. The highest possible value with 90% confidence of 15.1% cover was <br />utilized as the allowable herbaceous first hit cover in the mountain brush reference area. The <br />Division determined that the alternative approach meets or exceeds the standard set by the <br />historic methods used to determine sampling adequacy for the mountain brush reference area. <br />Although vegetation species diversity is not a criterion for Phase II bond release, the Division <br />evaluates cover data at Phase II to ascertain if the reclamation is approaching the diversity <br />success criteria. PSCM's species diversity standards for rangeland /wildlife habitat areas <br />consist of using the following four tests, with success demonstrated by passing the first (A) <br />and at least two of the remaining three (B, C, and D): <br />A. Mandatory test: No Overwhelming Dominant Species — No single species may <br />exceed 60% relative cover. <br />B. Alternative test: Total Species Density — The total mean species density in the <br />reclaimed area equals or exceeds the central 75% of the distribution of the area <br />weighted overall species density determined from cover sampling. <br />C. Alternative test: Distribution of Species Density in Comparison to the Reference <br />Area — Utilization of the Motyka similarity index to assess resemblance of the <br />distribution of species. <br />Peabody Sage Creek Mine Page 10 July 22, 2013 <br />Phase 11 Bond Release <br />