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} <br />• • <br />5. Backfilling and compacting with overburden, waste soils, shale, and sand spoils will be <br />done by means recommended by a geotechnical engineer. These could include <br />recommendations for mixing soils to achieve a relatively homogeneous embankment. <br />Settlement in an embankment is small, and using the clayey soils on site should be <br />relatively negligible. A rough rule of thumb is 1% settlement for a total height of <br />embankment. This would mean a 40 foot embankment would settle .4 feet. Most of htis <br />settlement would occur during construction and would be raised back to design grade <br />after settlement had occurred. Item #9 <br />Topsoil stockpiles Tor revegetation shall be a maximum of 20 foot in height and 100 foot in <br />width with 100 foot gaps between 300 foot long piles, and be placed parallel to the overbank <br />flow direction. For each phase a reserve of topsoil necessary for reclamation shall be kept in <br />each phase, until topsoil replacement has been completed for that phase. Whenever these <br />reserve topsoil stockpiles are present in the spring of the year and are expected to remain <br />undisturbed for longer than 6 months, they will be temporary revegetated by broadcast <br />seeding with low maintenance grasses to assist in temporary stabilization. The NRCS will be <br />consulted at that time on the type and rate of non-irrigated grass or grass seed mixture to be <br />broadcasted. The location and amount of topsoil stockpile for each phase is briefly described <br />below, and is also shown graphically on Exhibit C-1, Mining Plan Map. <br />Phase lA - 10,000 cubic yards in the northeast corner of the phase, between the <br />permanent internal access road and the Spring Creek/Fulton Ditches. <br />Phase 1B - 6,000 cubic yards along the Fulton Ditch in the 65' setback area. <br />Phase 2 - 12,000 cubic yards along the south boundary of the phase in the <br />minimum 100' setback area. <br />Phase 3 - 16,000 cubic yards in two locations: 8,000 cubic yards in the northeast <br />corner of the phase along the west boundary of the phase in the <br />minimum 100' setback area; and another 8,000 cubic yards in the <br />northwest corner of the phase. <br />Phase 4 - 18,000 cubic yards in two locations: 4,000 cubic yards along the east <br />boundary of the boundary of the phase in the minimum 100' setback <br />area, and another 9,000 cubic yards in the northwest corner of the phase. <br />In addition, temporary storage of both overburden for slope construction, and topsoil for <br />future revegetation, will be stored in the 35' setback areas of all phases. Calculations on both <br />topsoil and overburden amounts needed in reclamation are included on Exhibit C-2, Mining <br />Plan Map. A Typical Excavation and Reclamation Plan Section is also included on Exhibit F, <br />Reclamation Plan Map. Items # 9 and #10. and UD&FCD comments <br />2 <br />