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Peabody Sage Creek Mine July 2014 <br />SL -3 Phase III Bond Release Request <br />805,3 —180 <br />_ = 2,44 <br />1404.3 <br />, r 30 J <br />Since critical t, = 0.854 (one - tailed, alpha = 0.2, 29 df and tc is greater than this critical value, <br />reclamation success for Phase III background shrub density in 2010 is demonstrated. <br />A reverse t -test asserting that the 2010 BRB PSCM -1 Phase III concentration area woody <br />plant density is indistinguishable from 90% of the standard is as follows: <br />— (0.9 * techniCal standard) <br />��n <br />20922 — 1800 <br />tc _ = 1,48 <br />1400,2 <br />50 <br />Since critical t, = 0.849 (one - tailed, alpha = 0.2, 49 df and tc is greater than this critical value, <br />reclamation success for Phase III shrub concentration area density in 2010 is demonstrated. Also <br />note that the shrub concentration area in which adequate density has been demonstrated <br />occupies over 22 percent of BRB PSCM -1, well exceeding the minimum requirement of 5 <br />percent. <br />2011 Woody Plant Density Success Evaluation <br />The background density of 732.5 stems per acre observed in the 2011 BRB PSCM -1 Phase III <br />bond release area exceeded the 180 stems per acre performance standard. The mean of 2703.3 <br />stems per acre observed in the concentration areas also well exceeds the 1800 stems per acre <br />performance standard. The combined total aerial extent of woody density concentration areas <br />was 229.2 acres, or approximately 22% of the BRB PSCM -1 Phase III bond release block (1028 <br />acres). Hence the standard that there would be at least 5% of the Phase III BRB block with at <br />least 2,000 stems per acre (90% of the standard equals 1800 stems per acre) has been met for <br />2011. <br />16 <br />