2008-09-29_PERMIT FILE - C1981019A (13)

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RULE 4 PERFORMANCE STANDARDS virtually insignificant since the potential erosion occurs from snowmelt rather than raindrop impact. Therefore, if pre-mining levels of herbaceous vegetative cover can be re-established, logically a comparable level of erosion control will be achieved. 3. The ability to achieve adequate levels of herbaceous cover a Colowyo is, without question, quite possible. The vegetative monitoring completed at Colowyo during the last few years, and summarized in the Annual Reports, indicates that the premining levels of herbaceous cover are easily achieved. In fact, the vegetative data as summarized in the 1986 Annual Report indicates that the levels of herbaceous cover on the reclaimed areas may have exceeded the premine condition by 30% to 50%. The vegetative sampling serves to confirm what can be observed in the field. The revegetation at Colowyo is excellent and there is virtually no evidence of erosion attributable to a lack of cover. In fact the herbaceous cover existing at Colowyo meets or exceeds the premining condition and is undoubtedly providing significant competition with the woody specie seedlings. There is certainly no evidence that herbaceous cover values on the reclaimed areas should be set higher than the herbaceous cover of the premine areas in order to achieve bond release. Herbaceous Productivity Herbaceous productivity of the revegetated area will be considered adequate for final bond release if it is not less than 90% of the productivity, as determined from the reference area with a 90% statistical confidence. Woody Plant Density Through lengthy negotiations between the Division and Colowyo, Stipulation #5 requiring establishment of a shrub density standard for Colowyo was resolved. The resolution of the Stipulation #5 is summarized in the attached January 2, 1985 letter from the Division. The Division also requested a Technical Revision addressing the alternative seedmix to be employed in the shrub establishment areas. This alternative seedmix can be found in Section 2.05, Table 2.05-7. Diversity The initial Permit Application addressed Diversity by using the Shannon Weiner Index to measure the distribution of species within the existing premine vegetation community. Colowyo did not feel comfortable using such a complicated Index, but did so because it was the norm at the time to use this method. Since the initial Permit Application, the CMLRD regulations have been revised to allow for the use of comparisons of species composition based on cover between the reclaimed area and the undisturbed vegetation. This method of analyzing diversity was applied to the weighted premine vegetation cover data originally sampled and summarized in Section 2.04.10 on Table 2.04.10-2, 1980 Herbaceous Cover by Species. The percent contribution to diversity by each species contained within the predominate vegetation Rule 4 Performance Standards 4.15-10 Revision Date: 6/23/08 Revision No.: MR-91