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different soil horizons and thereby dilutes heavy clay concentrations encountered in <br />various subsoils. Although soil survey information and soil handling plans contained in <br />the PR-1 application were detailed and comprehensive, several issues of concern were <br />raised during the adequacy review. <br />The Division questioned what field characteristics would be used to define appropriate <br />salvage depths and requested justification for complete or partial salvage variances <br />proposed for a number of soil map units. Seneca provided appropriate detail in regard <br />to field salvage depth determinations. Generally, in shale derived soils dominated by <br />western wheatgrass/alkali sagebrush vegetation, a 6 inch depth will be salvaged. In <br />sandstone derived soils dominated by mixed brush vegetation, salvage will be terminated <br />at the sandstone bedrock contact or when a characteristic reddish brown clay subsoil is <br />encountered. <br />In response to the salvage variance concerns, various tables, exhibits and text sections <br />were revised to indicate that all suitable topsoil would be salvaged and that no salvage <br />variances were being requested. The proposed soil replacement depth was changed from <br />1.1 feet to 1.3 feet, Based on disturbed area modifications, updated soil balance <br />calculations, and reclamation plan changes made in association with PR-5, the <br />approved average replacement thickness in the original permit area is 1.3 feet, and <br />average replacement thickness in the South Extension area is 1.1 feet. Within <br />designated aspen planting exclosures, approved average replacement soil thickness <br />is 4.0 feet; within upland shrub establishment areas topsoiled in 2006, average <br />replacement thickness is 0.6 feet. <br />Certain statements in Tab 21 indicate that topsoil in map units 101, 103 and S103 may <br />be of questionable suitability based on rock fragment content. Current information <br />indicates that topsoil in the subject map units is suitable and will be salvaged. If the <br />topsoil is subsequently determined to be unsuitable, appropriate documentation will be <br />provided to the Division. All suitable soils will be salvaged, unless specific variances <br />pursuant to Rule 4.06.2(2) are approved prior to disturbance of the subject soil map <br />units. <br />Soil stabilization methods proposed by the operator consist primarily of minimal seed <br />bed preparation (resulting in a roughened soils surface) and use of either a straw mulch <br />or a quick growing annual grain cover crop on all topsoiled areas. Reclaimed areas will <br />be inspected annually by the operator as required by the proposed rill and gully <br />maintenance plan, and additional stabilization measures will be implemented if results of <br />the annual evaluation warrant such modifications. Graded spoils with excessive clay <br />content as detected by monitoring described in Section III.E, above, will be deep ripped <br />to relieve compaction, pursuant to 4.06.4(1). <br />Seneca II-W Findings Document 50 June 12, 2006 <br />Permit Renewal No. 5 <br />