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Seneca 11 Mine June 2011 <br />SL-5 Phase /I Bond Release Request <br />the mountain brush, does not have this issue and first hit herbaceous cover sample adequacy with <br />reasonable sample sizes is attainable. <br />To address this, a proposal was made to CDRMS in 2009 by ESCO Associates on behalf of <br />Seneca Coal Company to use all hit herbaceous cover as the primary basis for sample adequacy in <br />the mountain brush type. From there, adjustments and a ratio procedure (the ratio of first hit <br />herbaceous cover to all hit herbaceous cover) is applied to the data with additional sample <br />adequacy checks made during the process. The final ratio value is used to return the all hit <br />herbaceous cover mean to the first hit herbaceous cover basis needed to be used in the weight <br />averaged calculations for the success standard. For greater detail on the basis and calculations, <br />please refer to the discussion in the revegetation success evaluation report by ESCO Associates <br />included in Attachment E - Revegetation Supporting Documentation. Particular attention <br />should be made to the text of the report beginning on page 10, Table 6-4 in Appendix 6 and the <br />correspondence with CDRMS in Appendix 7. <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 /> Allowable Herbaceous <br />Vegetation Type % of Pre-mining Area <br /> 1 <br />Cover on a first-hit basis <br />Mountain Brush 12.42 83.0 <br />Sagebrush 44.7 17.0 <br />Herbaceous cover adjusted by subtracting noxious weeds and annual/ biennial plant cover in <br />excess of 10% of the remainder. <br />2 Value determined from the ratio of first hit herbaceous cover to all hit herbaceous cover (see <br />Table 6.4 in Appendix 6, 2010 revegetation success evaluation report, Attachment E - <br />Revegetation Supporting Documentation). <br />2010 Mountain Brush Reference Area First-hit Allowable herbaceous cover 12.4 x 2 = 24.8% <br />2010 Sagebrush Reference Area First-hit Allowable herbaceous cover 44.7 x 2 = 89.5% <br />90 percent of the Cover Standard = 0.90 [0.83 X (24.8) + 0.17 X (89.5)] = 32.2% <br />9