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Assessment of BRB for Compliance with Phase 11 Performance Standards <br />COVER <br />The area-weighted average of reference area values was calculated based on the following <br />information: <br />Vegetation Type Percent All-Hit Allowable <br />Herbaceous Cover % of Pre-mining Area <br />Aspen 87.30 24.4 <br />Mountain Brush 40.55 48.9 <br />Sagebrush 35.80 24.0 <br />Steep Mountain Brush 17.30 2.7 <br />The weighted average is calculated as 87.30 X 0.244 + 40.55 X 0.489 + 35.80 X 0.240 +17.30 X <br />0.027 = 50.19 . The cover performance standard is thus 50.19 x 0.9 = 45.17 <br />Application of a one-sample t-test (using the traditional null hypothesis) that tests the assertion <br />that the 2010 Phase II BRB mean allowable cover is indistinguishable from 90% of the standard <br />is contained in the following calculation: <br />t? _ (45.17 - 45.02) / (15.69 / sqrt 29) = 0.058 <br />Since critical t = 1.306 (one-tailed alpha = 0.1, 34 df) and the absolute value of t. is less than this <br />critical value, reclamation success for Phase II is demonstrated. <br />SPECIES DIVERSITY <br />The species diversity determinations are based on the approved diversity evaluation procedures <br />contained in Tab 22 "Revegetation Plan" of the CDRMS Yoast Mine permit. <br />With regard to Test A, a determination of PASS was made because the species with the greatest <br />relative cover (Medicago sativa) had 16.9 percent relative cover (far less than the 60 percent <br />limit). <br />With regard to Test B, <br />Weighted Reference Area Species Density = 21.26 <br />Phase 11 Bond Release Block Species Density = 25.38 +/- 1.28