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NOTES ON THE DEVELOPMENT OF REFERENCE AREA — BASED PERFORMANCE STANDARDS <br />Corrections for Noxious Weeds and Excess Annuals <br />Upon the formal comparison of cover and production data from reclaimed areas to applicable <br />performance standards, observed total first -hit herbaceous cover percentage and collected production, <br />must be adjusted for excessive contribution by annual /biennial species (i.e. no more than 10 percent <br />relative cover or production, CDMG 1995, Guidelines Regarding Selected Coal Mine Bond Release <br />Issues, 1(IV) A(4)). Herbaceous cover and production values used in such comparisons also must <br />exclude values for species present on the Routt County Prohibited or Restricted Noxious list or that are <br />listed as noxious by the State of Colorado (Colorado Dept. of Agriculture, Division of Plant Industry, Title <br />35, Article 5.5, 101 -119, Lists A and B of Rules as replaced 2003). For purposes of assessment of <br />reclamation adequacy, first -hit herbaceous cover data from reference area sampling is used as per <br />Seneca II Mine permit provisions. <br />Upward Adjustment of the Mountain Brush Cover Standard <br />Sample adequacy for total vegetation cover was achieved for the reference areas and BRB -5. For total <br />allowable herbaceous cover, adequacy based on first -hit values was achieved for BRB -5 and the <br />Sagebrush Reference Area, but it was not for the Mountain Brush Reference Area. <br />In consideration of the lack of a sample size sufficient to detect a 10 percent reduction in the mean with <br />90 percent confidence (i.e. sample adequacy), the upper limit of the possible values of the true mean <br />(with a sample size of 18 in 2012 and 21 in 2011) was determined. This can be done in either of two <br />ways. <br />It is also to be noted that provisions of the permit include the weighting of the data from the two reference <br />areas in accordance with the original relative abundance of the types in the pre- mining landscape (83% <br />mountain brush, 17% sagebrush /snowberry). In the process of weighting, a reliable estimate of variance <br />is lost. Thus the reference area standard thereafter in the process is treated as a technical standard (i.e. <br />without confidence limits) and one - sample t- testing is used. <br />5 <br />