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Trapper's approved postmining land use is rangeland for the lands included in SL-02. Three different <br />rangeland vegetative communities are designated on reclaimed areas of the Trapper Ntine: these are <br />called A, B, and C. The bond release parcels in this bond release request are only rangeland ,~ and <br />B. The vegetative cover success standard for rangeland A is ~3 percent, with at leas[ 33 percent <br />herbaceous cover and no more than 19 percent litter. For rangeland B, the cover standard is also 52 <br />percent, but herbaceous cover has [o be at least 29 percent while litter cannot exceed 23 percent. (For <br />rangeland C, the cover standard is 47 percent; the herbaceous cover must be at least Z~ percent and <br />the litter cannot be greater than 22 percent.) <br />When counting the plants in the field which comprise cover, the Division's bond release Guideline <br />prohibits counting any noxious weeds. Also any annual or biennial species which comprise more <br />than 10% of the total cover should not be included in the count (page 7 of the Division's bond <br />release Guideline). Trapper's bond release submittal addresses revegetation success with <br />revegetation data that Trapper has collected. <br />Sediment Yield Limitation <br />The amount of bond that can be released in a Phase II release is limited by Section 3.03.1(3)(b) if <br />the released lands aze contributing excessive sediment to adjacent lands. The limitation is: " No more <br />than sixty (60) percent of the bond shall be released so long as the lands to which the release would <br />be applicable are contributing suspended solids to streamflow or runoff outside the permit area in <br />excess of premining levels as determined by baseline data or in excess of levels determined on <br />adjacent nonmined azeas". Trapper addresses this requirement by including in the bond release <br />submittal a computation (using the SEDCAD 4 computer program) of the amount of sediment that <br />the released lands yield before and after mining as a result of a 101-year, 24-hour precipitation event. <br />The submittal also contains a comparison of pre-mining versus post-mining soil loss predicted by <br />the Universal Soil Loss Equation. <br />Special Conditions <br />Section 3.03.1(2)(b) of the Regulations imposes special conditions on a Phase II release if mining <br />operations have impaired the use of prime farmland or an alluvial valley floor. Those special <br />conditions do not apply in Trapper's bond release request because there is no prime farmland or <br />alluvial valley floor affected by the bond release parcels. in addition, Trapper's postmining rangeland <br />use exempts the bond release from the special conditions required by Section 3.03.1(3)(e) for a Phase <br />II release which involves industrial, commercial or residential postmining land uses. <br />Topsoil Replacement Thickness <br />The Division's bond release Guideline, calls for verification of replaced topsoil thicknesses in a <br />Phase II bond release evaluation. Trapper's approved reclamation plan specifies that topsoil is to <br />be replaced to a minimum thickness of l3 inches on rangeland sites A, B and C. (There is no <br />Trapper Mine <br />Phase II Bond Release Page 4 12/23/99 <br />