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Peabody Sage Creek Mine <br />SL -3 Phase III Bond Release Request <br />July 2014 <br />Appendix C in the vegetation report contained in Attachment D to this document for additional <br />information. <br />A reverse null t -test of the assertion that the 2011 BRB PSCM -1 allowable herbaceous <br />production exceeds the Weighted Reference Area allowable herbaceous production performance <br />standard is as follows: <br />5F— (0.9 * Weighted Reference Area perf ofi „i ance standara ) <br />UO <br />2815.8 — 812.7 <br />tr _ <br />1356.1 <br />130 <br />Since critical t, = 0.854 (one - tailed, alpha = 0.2, 29 dfsat) and tc is greater than this critical value, <br />reclamation success for Phase III herbaceous production for 2011 is demonstrated. <br />Woody Plant Density. The criterion for determining success of woody plant density at the <br />PSCM mine site is as follows: Background average woody density >_ 200 stems per acre with at <br />least 5% of the BRB bond release block possessing >_ 2000 stems per acre of concentrated woody <br />density. Success is evaluated using 90% of the standard values or 180 stems per acre and 1800 <br />stems per acre, respectively. <br />The locations of high density woody plant "Concentration Areas" in the BRB PSCM -1 bond <br />release area were documented using aerial photography (Routt County DOQQ 2009) verified by <br />field mapping in the summer of 2010. During the mapping, high density was reserved for those <br />areas apparently (visually) greater than or equal to 2000 shrubs per acre (25 shrubs per 100 sq.m.). <br />All portions of the BRB PSCM -1 bond release block outside of these concentration areas were <br />labeled as `Background" density. Table 6 below summarizes the results. <br />14 <br />