2012-01-18_GENERAL DOCUMENTS - C1994082

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areas and drainages and was drilled at a rate of 19.7 lbs /acre. Seed mix 3 is for soils with alkaline conditions and lowland areas that have the potential to be quite wet. It was drilled at a rate of 16.6 lbs /acre. Most areas were drill seeded with the appropriate seed mix and steep slopes were broadcast seeded at twice the drill rate. Fertilizers and mulch were not applied at the Yoast Mine. To meet the woody plant density standard, several approaches were used to establish woody plants. Shrubs species were included in the general seed mixes (seed mix 1 -3, see above), concentrated shrub areas were planted with a shrub seed mix (seed mix 5) and containerized stock was planted in fenced shrub /tree plots. Seed mix 5 was planted at a rate of 21.25 lbs /acre in the shrub concentration areas and these plots were not seeded with the permanent seed mix to reduce the competition with the grasses. There are 5 shrub /tree plots within the bond release area that are protected by an elk -proof fence. These plots contain a variety of woody plant species, four of which are upland woody plots and one aspen plot. Map 22 -1 of the Yoast permit shows the location and the year planted of the shrub concentration areas and the shrub /tree plots. Table 22 -8 in the permit lists the primary species and densities used in the planting areas. Fertilizers and mulch were not applied in the shrub concentration areas and shrub /tree plots. Revegetation success criteria and success demonstration methods are presented in Tab 22 of the approved permit. For Phase H bond release, cover is the only criteria required. Summary statistics and a narrative evaluation for both the reference and bond release areas are on pages 4 -8 of the SL -3 bond release application. Transect data tables, sample adequacy calculations, diversity calculations and species lists are presented in Attachment E of the same application. The Yoast Mine utilizes an extended reference area to represent the four major premining community types (Aspen, Mountain Brush, Sagebrush and Steep Mountain Brush) disturbed during the life of the mine. The extended reference area lies within the permit boundary but outside the disturbance boundary and a minimum acreage of each community type is maintained. Weighted averages for cover and production comparisons are derived from the percentage that each community type was present in the premining surface area affected by mining. Map 2 in Appendix E of the SL -3 Application shows the locations and community types of the extended reference areas. A narrative describing the extended reference area approach for measuring revegetation success is on pages 32 -45 of Tab 22 in the permit application package. Sampling of the reference areas was conducted in July 2010, with 15 -17 transects in each of the four reference area community types. An average of the all -hit allowable herbaceous cover of the four reference area types was calculated. Allowable cover is the reference area all hit cover with noxious weeds, woody vegetation and cover contribution greater than 10% by annuals /biennials removed (page 4, SL -3 Bond Release Application). The success standard for cover based on 90% of the weighted mean allowable all -hit herbaceous cover for the reference areas with 90% statistical confidence is 45.17 %. Cover sampling in the bond release block was also undertaken in July 2010. Thirty five transects were sampled initially, but the Division determined that six transects were situated in areas outside of the requested bond release area. The operator revised and resubmitted the vegetation sampling data for the remaining twenty -nine transects. After the revised data was submitted, two landslides occurred within the bond release request area. The Division Yoast Mine C- 1994 -082 Page 6 of 17 Phase II Bond Release SL -3