2011-04-06_REVISION - C2009087 (4)

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Peabody Sage Creek Mine SL-1 Phase 11 Bond Release Request March 2011 Since the Phase II bond release. block value does not exceed the standard, a determination of FAIL is made. The Test C standard uses the Motyka similarity index to assess resemblance of the distribution of species density by lifeform for reclamation vegetation to that of the reference area. Because the average internal resemblance (i.e. between-sample similarity) of reference area species density data is often in the range of 70%, this is the PSCM species density similarity standard in Test C. The Motyka similarity index is: ISmo = 2c / (a + b) Where: c = the sum of the smaller of the paired species density values (for each life form) for reclaimed and Reference Areas* a = total of species density values for lifeforms of the reclaimed areas b = total of species density for the lifeforms of the Reference Areas* *Weighted average lifeform species density using the Yoast Reference Areas • (weighted as specified under Cover above). 0 The results of Test C show the similarity of the species density by life form of the Phase II bond release block to that of the weighted reference area means was 0.86, exceeding 90 percent of the standard of 0.70 (.63) and indicating a PASS for this test. With regard to Test D, the reference area derived weighted average species density of native species is 28.7 per 100 sq.m. The cumulative number of native species in the nine 100 sq.m. samples for the Phase II bond release block (that constitutes a minimally adequate sample) is 35, exceeding 28.7 per 100 sq.m and indicating a PASS on this test. Note that when all 30 Phase II bond release block samples are considered, 56 total native species were encountered. Based on meeting mandatory Test A and two out of the three alternate tests of species diversity, species composition and diversity are demonstrated for the Phase II bond release block. 12