2011-10-03_REVISION - C1980007 (2)

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• • Achievement of Revegetation Success The report, Phase II Bond Release Vegetation Report (2011); Mountain Coal Company., LLC; West Elk Mine, Somerset, Colorado documents achievement of the applicable revegetation bond release criteria are appended to this application. A summary of the applicable revegetation success criteria and sampled values for 2011 for the West Elk Mine follows. Vegetation Cover The revegetation success criterion for total vegetation cover for the West Elk Mine is a standard based on quantitative sampling over multiple years at the Historic Records Study Area at the West Elk Mine. The final revegetation success criterion for total vegetation cover is 90 percent of 54.07 percent live vegetation cover with 90 percent statistical confidence. West Elk Mine Reclaimed Areas Total Vegetation Cover (2011) Final Total Vegetation Cover Success Criterion: 54.03 % total vegetation cover 2011 Reclaimed Areas X bar S N Nmin 57.53 9.35 30 5 Based on the results of the 2011 quantitative sampling, the reclaimed areas exceeded the final revegetation total cover vegetation success criterion of 54.03 percent, exceeding the final revegetation success criterion for vegetation cover. Species Composition The final species composition standard requires that there be at least four perennial species, of which three are warm season grasses and one a cool season grass. No one component of the above four species should comprise greater than 40% relative importance nor less than 3% relative importance. Relative importance is to be measured by calculating relative cover of the revegetation species. Vegetation species which may be used in the calculation of species composition may be any plant species not defined as a noxious or prohibited plant species, and may be native or introduced. Mountain Coal Company, LLC West Elk Mine 2011 Phase II Bond Release Page 8