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determining vegetative reclamation success. The Division has determined that Chevron has followed <br />its approved sampling methodology and has met its requirements for statistical demonstrations. <br />Vegetation observed during the July 20, 2009 bond release inspection within the areas recently <br />requested for bond release at the Edna coal mine was visually dominated by alfalfa, cicer milkvetch, <br />perennial grasses, American vetch, rabbitbrush and yellow sweetclover. Houndstongue rosettes were <br />observed frequently in the understory in these areas; they were, however, not visually dominant. As <br />the inspection moved along the slope of the West Ridge Area, vegetative cover was observed as being <br />generally good, with varying cover density. At the western extent of the West Ridge non-topsoiled <br />area, numerous antelope bitterbrush shrubs were observed, along with an apparent decrease in rubber <br />rabbitbrush shrubs. A patch of musk thistle was also encountered in this area. The patch was <br />approximately 30 ft by 60 ft in size, and sparse. Other than observing occasional weed patches and <br />houndstongue rosettes, no problems were encountered in the non-topsoiled reclaimed areas. <br />Gullies were not observed in the reclaimed areas. Minor rilling was noted between contour benches in <br />the non-topsoiled West Ridge block, but this rillying was of limited frequency and extent. Based upon <br />the observation of perennial grass establishment in the bottom of the rills, the rills did not appear <br />active. Permanent drainages and contour benches were in good condition and were not eroding. <br />Although the Division concurs with your comments concerning the presence of noxious weeds within <br />the bond release areas, the amount of noxious weeds makes up a very small portion of the overall <br />vegetation established at the site. This observation is substantiated by the sampling data submitted <br />with the bond release application. Based on the July 20, 2009 bond release inspection, Chevron has <br />been supplied with a map delineating the locations within the areas requested for bond release in which <br />weed management should be implemented. Chevron has been additionally asked to provide us with <br />evidence of weed management conducted throughout the 10-year liability period. The Division will <br />conduct a follow up inspection to assure that weed control efforts recommended during the bond <br />release inspection have been implemented and to assess the effectiveness of the control prior to making <br />any decisions regarding the bond release applications. <br />With regard to your comments pertaining to the presence of rubber rabbitbrush (Ericameria nauseosa), <br />it should be noted that Rubber rabbitbrush is a native species that was not included in Chevron's <br />approved seed mix (Table 4.4-2 of the DRMS permit for the Edna mine). Woody species that were <br />included in the approved rangeland seed mix include Rosa Woodsii (Woods' rose), Prunus virginiana <br />(chokecherry), Cercocarpus montanus (mountain mahogany), Purshia tridentata (antelope <br />bitterbrush), Atriplex cansecens (fourwing saltbush), and Amelanchier alnifolia (Saskatoon <br />serviceberry). The presence of some of these seeded woody plant species was observed during the <br />July 20, 2009 bond release inspection. <br />It should be noted that surface coal mine permittees in northwest Colorado have consistently had <br />difficulty establishing woody species in reclaimed mining areas. This was confirmed during a study <br />conducted by DRMS between 2000 and 2005 in cooperation with Colorado State University's Range <br />Science Department. This "Shrub Establishment Study" evaluated the use of different techniques to <br />establish mountain shrub woody species at reclaimed surface coal mines.