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vegetation cover and total herbaceous production means with lower overall precipitation <br />amounts. Species composition numbers and woody plant density numbers remained <br />nearly constant or increased slightly since sampling in the late 1990's. <br />In 1999, the CDRMS requested that MCC obtain additional sample values at the HRSA <br />during a defined "wet" year ("pre-growing season" precipitation value greater than 13.71 <br />inches). As Figure 4 depicts, there has not been a defined "wet" year in the intervening <br />time period (2000-2010). Based on the mean "pre-growing season" precipitation values <br />from the 2000-2010 time period, there appears to be a downward trend in the average <br />value for total "pre-growing season" precipitation. <br />To finalize the revegetation success criteria for the West Elk Mine, and in light of the <br />lack of predictable defined "wet" year, it is proposed that the existing data from the 1996, <br />1997, 1998, and 2010 quantitative sampling of the HRSA be utilized to calculate and <br />establish revegetation success criteria for total vegetation cover, total herbaceous <br />production, species composition and woody plant density. The proposal would entail the <br />averaging of the data from each parameter, excluding species composition, and using the <br />resulting parameter value as the revegetation success criterion. <br />6.1 Total Vegetation Cover <br />For total vegetation cover on reclaimed areas, the proposed revegetation success criterion <br />would be 53.04 percent total live vegetation cover. This value is derived from the mean <br />of the total vegetation cover values from the 1996, 1997, 1998, and 2010 quantitative <br />data. Reclaimed areas will be considered successfully reclaimed to the final revegetation <br />success criterion if the total vegetation cover on the reclaimed area is not less than 90 <br />percent of the total vegetation cover value of 53.04 percent, with 90 percent statistical <br />confidence using a one-tailed test. <br />6.2 Total Herbaceous Production <br />For total herbaceous production on reclaimed areas, the proposed revegetation success <br />criterion would be 180.38 g/m2 total herbaceous production. This value is derived from <br />the mean of the total vegetation cover values from the 1996, 1997, 1998, and 2010 <br />quantitative data. Reclaimed areas will be considered successfully reclaimed to the final <br />revegetation success criterion if the total herbaceous production on the reclaimed area is <br />not less than 90 percent of the total herbaceous production value of 180.38 g/m2 with 90 <br />percent statistical confidence with a one-tailed test. <br />6.3 Woody Plant Density <br />The area of the Historic Records Study Area is approximately 5.49 acres. A census of the <br />total number of woody plants by species was conducted in 1996, 1997, 1998, and 2010. <br />The results of these counts are contained in Table 7. The average number of woody <br />plants within the Historic Record Study Area from the four years of sampling was 74. <br />When the woody plant number is calculated on a per acre basis the woody plant density <br />(per acre) is 13.47 woody plants per acre. The revegetation success criterion for woody <br />Mountain Coal Company, LLC Page 12 <br />Historic Record Study Area Vegetation Sampling Report: 2010