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In the bond release application, Flatiron Companies presented data for each reference area and weighted them equally (in contrast to the reference area 75/25 weighted standard specified in the approved permit). The operator showed all reclamation achieved this success standard. However, the Division evaluated success using the 75/25 weighted standard approved in the permit application for cover and productivity. The cover in the reclaimed area did not achieve the 75/25 weighted reference area standard. Rule 4.15.8(3)(a) allows for a lower percent of cover where there is danger of herbaceous vegetation outcompeting woody vegetation. This evaluation is presented below. Revegetation at the Bourg Mine was sampled in 1997 and 1998. Data was collected from the 29 acre 1984 reclaimed area and the 84 acre 1988 reclaimed area. Reclaimed area data was weighted by acreage to calculate a combined reclamation mean value for cover, productivity and woody plant density. Cover data was collected as approved by the DMG in 1997 and 1998. Combined herbaceous and shrub cover were recorded and used for comparison. The cover standard from the reference aeeas (90% of the reference aeeas weighted sample means) was 35.1% in 1997 and 36.4% in 1998. The combined reclaimed azea cover sample means were 31.1% in 1997 and 32.7% in 1998. Since cover in the reclaimed area was less than the reference area standard each year, one-sample t- tests were nut on each year's data to determine whether the differences were statistically significant at the 90% level of statistical confidence (alpha = .10; 1 tail, n-1 d.f.). The results of the statistical test showed that the weighted cover from the reclaimed areas was less than 90% of the weighted reference area cover with 90% statistical confidence each year. Rule 4.15.8(3)(a) allows a lower percentage of cover than is required by the above referenced statistical test, if the lower cover is advisable where there is danger that herbaceous vegetation will out-compete the woody vegetation and hinder its successful establishment, and the lower percentage will be adequate for erosion control. The reclaimed area cover was evaluated using this Rule. To achieve the post mining goals of reestablishing sagebrush, the Bourg Mine seed mix contained thirty-seven percent big sagebrush (PLS/square foot basis). This high percent of sage was included, because herbaceous vegetation often outcompetes the woody species on reclaimed lands. Sage reestablishment was a critical component of the revegetation plan to mitigate for the impacts to the sage grouse habitat. Big sagebrush has been successfully established on the reclaimed lands. Erosion control is adequate in all reclaimed areas. After the second year of seeding, only minor rills and gullies have been noted. A cover factor of 60% (includes litter) was considered in the original SEDCAD demonstration discussed previously and the cover factor for the reclaimed area in 1998 was 79%. This additional vegetative cover and litter component provide additional erosion control. Bourg Mine 6 Final Bond Release Permit No. C-81-021 January 18, 2000