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C- 1991 -078 27 May 201 <br />SL -02 Review Page <br />the split grassland reference area. Statistical sample adequacy was not achieved <br />in either of the sagebrush reference areas, and was not evaluated for the grassland <br />reference areas combined (as would be required for bond release success <br />demonstration). <br />d Chart 3 "Success Comparison..." shows the likelihood that the sampled <br />reclamation unit would easily meet the reference area cover standard. However, a <br />valid statistical demonstration that the cover standard was achieved in the <br />sampled reclaimed unit was not made, because sample size within the reference <br />areas was insufficient. Further, the CCA report did not include a comparison of <br />reclaimed area cover mean to (90% of acreage weighted reference area cover <br />mean, as would be required to demonstrate success for Phase If bond release. <br />For the various reasons listed here above, the Division requests that the Honey wood <br />submit a request to formally withdraw the SL -02 Phase II bond release application. <br />An alternate option would be to subrit' a revised reegetation study, in the near <br />future (Summer 2010), that would fulfill the requirements for statistical adequacy. <br />2. The CCA vegetation report contains a Section 3.4 "Recommendations", which includes <br />recommendations for revegetation sample design to be followed in future bond release <br />sampling efforts. The Division is in general agreement with the recommendations of <br />Section 3.4. However, a more detailed description of the area weighting procedure and <br />statistics for use in comparison of reference area data to reclaimed area data will need to <br />be provided. The need for such clarification is due in part to the complexities associated <br />with the establishment and documentation of the reference areas originally, in 1991 and <br />1992. The CCA report makes reference to "50150" weighting for the two sagebrush <br />reference areas (SREF-A and SREF -, established in 1991 and 1992 respectively), but <br />supporting rationale would need to be provided. The major portion of the disturbance is <br />in Mine Area 1, which is associated with SREF -A, the southern sagebrush reference area., <br />established in 1991. Both sagebrush reference areas were used for comparison to the <br />much smaller Mine Area 3 disturbance, in 1992. As such, it would seem that BRED' - <br />would logically be weighted more heavily than S EF- (since all of the sagebrush <br />acreage that originally occurred within the disturbed portion of Mine Area 1, and half of <br />the sagebrush acreage that originally occurred within the disturbed portion of Mine Area <br />3, would be represented by SREF- . SREF -A was apparently the more productive of <br />the two sagebrush reference areas when both were sampled in 1992. <br />Please consider this ratter and provide detail and justification for the area <br />weighting procedure within a minor revision application addressing Phase 11/111 <br />reegetation sampling plans and revgetation success demonstration approaches, <br />prior to submittal of the next Phase II or Phase III bond release application. Area <br />weighting should reflect the percentage of the reclaimed area to be represented by <br />the split Grassland Reference Area, SR F- , and SR F- , based on percentage of <br />the disturbance that was originally Grassland, percentage that was originally <br />Sagebrush represented by only SR F- , and percentage that was originally <br />Sagebrush represented equally by SRF -A and SRF -. Any reclaimed acreage <br />