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Phase II Bond Release Criteria <br />Establishment of vegetation which supports the approved postmining land use and which meets <br />the approved success standard for cover based on statistically valid data collected during a single <br />yeaz of the liability period are prerequisites for Phase II bond release.zv <br />A third prerequisite to Phase II bond release is that streamflow or runoff outside the permit area <br />aze not contributing suspended solids in excess of premining levels as determined by baseline <br />data or in excess of levels determined on adjacent nonmined azeas.30 <br />A fourth prerequisite to Phase II bond release is thickness of replaced topsoiL31 The required <br />thicknesses of replaced topsoil at the Hayden Gulch Mine is to an average of 21-inches.32 <br />Section 3.03.1(2)(b) imposes special conditions on a Phase II release if mining operations have <br />impaired the use of prime farmland or an alluvial valley floor. This application is, by exception, <br />in compliance with these criteria. None of the lands affected by the bond release block aze <br />designated "prime farmland" or "alluvial valley floor". In addition, HGTI's postmining uses of <br />livestock grazing, rangeland, and wildlife habitat comply, by exemption, the bond release from <br />the special conditions required by Section 3.03.1(3)(e) for a Phase II release which involves <br />industrial, commercial or residential postmining land uses. <br />Phase III Bond Release Criteria <br />Vegetation success criteria are as set forth on page 4.15-2 of the permit application package. <br />The weighted mean of the reclaimed area herbaceous vegetation cover percentage must be 90% <br />or greater of the reference azea percent herbaceous vegetation cover, with 90% statistical <br />confidence. <br />The woody plant density standazd as stated in on page 4.15-2 of the permit application package is <br />750 stems per acre within the three shrub-enhancement azeas. <br />Herbaceous vegetative productivity of reclaimed areas must be 90% or greater of reference area <br />herbaceous vegetation productivity with 90% statistical confidence. <br />The diversity standard requires a minimum of 5 species each having a minimum of 5% relative <br />cover, with no one species exceeding 40% relative cover, nor any three herbaceous species <br />combined relative exceeding 75%. <br />z9 Section 3.03.1(2)(b) <br />so Section 3.03.1(3)(b) <br />31 Division's Guideline Re ag rding Selected Coal Mine Bond Release Issues April 18, 1995 <br />sz Permit Application Package, page 2.05-6 <br />Hayden Gulch Mine Page 10 July 31, 2006 <br />SL-04 <br />