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• Cover <br />Sample Size 30 <br />Minimum Adequate Sample Size 25 <br />Assessment of BRB for Compliance with Phase 11 Performance Standards <br />Calculation of 90 percent of the cover performance standard appropriate for 2010 sampling is <br />demonstrated below and is based on the following information: <br />Vegetation Type Allowable Herbaceous <br />Cover on a first-hit basis* % of Pre-mining Area <br />Mountain Brush 12.4 83.0 <br />Sagebrush 44.7 17.0 <br />" tierDaceous cover as/usleo oy suvirdciuiy nuvuus wvv- anu ani?uavu,c?una, N,a,,, wvv, ,,, v.??? ?•• ,?? ••? <br />remainder. <br />2010 Mountain Brush Reference Area First-hit Allowable herbaceous cover X 2 = 24.8% <br />• 2010 Sagebrush Reference Area First-hit Allowable herbaceous cover X 2 = 89.5% <br />Calculation of 90, percent of the cover performance standard appropriate for 2010 sampling is <br />demonstrated below. <br />90 percent of the Cover Standard = 0.90 [0.83 X (24.8) + 0.17 X (89.5)] = 32.2% <br />The reclaimed (BRB) area sampled in 2010 at thirty locations to produce cover data applicable to <br />a potential Phase II bond release application exceeded 90% of the standard (32.2% allowable <br />cover). The figure for allowable cover in the 2010 Phase II BRB (37.5%) is the result of <br />subtracting tree, shrub and non-herbaceous cover (1.2%) and perennial noxious weed cover <br />(0.44%) and "excess annual/biennial cover" (0.5%) from the observed all-hit total vegetation <br />cover of 39.6%. <br />A one-sample t-test of the assertion that the 2010 Phase II BRB allowable cover is <br />indistinguishable from 90% of the standard is as follows: <br />tc = (37.5 - 32.2) /(14.2 / sqrt 30) = 2.044 <br />• 13