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Therefore, the fallowing stipulation is proposed: The applicant must include in their analyses for evaluating revegetation success an a/nalysis of(( woody plant den~/s~ity. 4 ~LL E'.55 ~ d'I~EI'ICL l.Ul ~~ bT c=~u, l}C lr. rl+E y' ~'Jt~ `IJ~ ~ E ~~ L~L~ The applicant has committed to a method of utilizing diversity indices which will be determined by the Division of Mined Land Reclamation; or the applicant will propose more stringent success criteria for post-mining plant community diversity (page 17, Addendum I of the permit application). A student t-test comparison of the reclaimed areas and the weighted average of the reference areas will be made to evaluate i revegetation success. If the null hypothesis (Ho: Revegetated area measurement > Reference area measurement) is accepted at the ~~ 90% confidence level, then revegetation efforts will be e' considered successful. Wyoming Fuels has utilized a 20% accuracy level for calculation of sample adequacy for big sagebrush productivity in 1979 and 1980, alkali sagebrush productivity in 1980, and woody plant density in both the permit and reference areas (page 17, Addendum I of the permit application). Thus, sample adequacy required by the Colorado Permanent Regulatory Program to acheive a level of accuracy within ten percent of the mean was not achieved and the applicant has not demonstrated that the proposed reference areas are comparable to their equivalent areas to be disturbed. Therefore, the following stipulation is proposed: The applicant must submit a plan to resample the two vegetation types and the two reference areas utilizing a lOX accuracy for calculation of sample adequacy. A species list for each community should be included. These data will be used to describe the vegetation types and to determine their similarity to their respective reference areas. A plan for the vegetation studies must be supplied to the regulatory -95-