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Peabody Sage Creek Mine <br />SL-1 Phase // Bond Release Request <br />0 <br />• Reclamation (Species Composition and Diversity) Success <br />March 2011 <br />The species composition and diversity evaluation below is based on the species diversity <br />revegetation success evaluations presented in Exhibit 2.05.4-E1 of the approved PSCM <br />permit. The seasonality of northwestern Colorado native range surrounding the PSCM permit <br />area is cool season and the established reclamation is also cool season. <br />Test A requires that no single plant species may exceed 60% relative cover. A determination <br />of PASS was made because the species with the greatest relative cover (Thinopyrum <br />intermedium) had 29.98 percent relative cover which is far less than the 60 percent limit. <br />Test B requires the total mean species density in the reclaimed area equals or exceeds the <br />central 75% of the distribution of the area weighted overall species density determined from <br />the cover sampling in the 100 sq.m. sample plots of the reference area. Species density <br />numbers were subjected to sample adequacy assessment. For purpose of setting the range of <br />• species density within the Reference Area, the 75% range of variation would be established <br />as: <br />z X s <br />Where: <br />z = the number of standard deviations (both ways from the mean) encompassing 75% of the <br />normal distribution = 1.15; (see Rohl(and Sokal 1969, Table P) <br />s = area weighted species density standard deviation for the reference area (n-1) <br />The standard is the point at which the central 75% of the distribution of overall species <br />density in the reference areas begins (the midpoint (probability distribution) of the lower half <br />of the range of variation for the reference area). Mathematically this is: <br />Weighted mean reference area species density (no. of species per 100 sq.m.) - 1.15 s. <br />The results of Test B are: <br />Weighted reference area species density = 25.34 <br />Phase II bond release block species density = 23.37 +/- 1.12 <br />11