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6.4.4 EXHIBIT D — MINING PLAN <br />Mining Description <br />The Mining Plan is described in this section and correlates with Exhibit C-2 - <br />Mine Plan Map. Mining is sequenced with designated mining Cells 1-4 as shown <br />on Exhibit C-2. Mining will be accomplished by the "dry -mining" method. Prior to <br />excavation below the water table, a continuous soil / bentonite slurry wall will be <br />constructed around the entire perimeter of the mining area followed by removal <br />of pore water within the slurry wall (dewatering). The location of the slurry wall is <br />shown on Exhibit C-2. <br />Mining will employ conventional aggregate mining techniques including the use <br />of scrapers and backhoes to excavate topsoil, overburden and sand and gravel <br />and haul trucks to move materials as either backfill or as sand and gravel to be <br />further processed at the gravel plant site. Sand and gravel processing will be <br />located onsite and finished materials will be trucked offsite. The mine plan map <br />shows a fixed gravel plant location with stockpiles on the south-eastern edge of <br />the site for the entire life of the project other than for a short period where this <br />location will be mined (6 months). This location is out of the newly designated <br />DRAFT (as yet without final approval by FEMA) location of the Floodway of the <br />South Platte River in this area, but is still in the Floodplain. Alternatively, ASCI <br />may choose to utilize totally mobile equipment for processing and stockpiling of <br />sand and gravel. This equipment is tracked or on wheels and can be easily <br />moved to another location or from the site entirely. All stockpiling will always be <br />located out of the Floodway. A Floodplain Use Permit will be obtained from the <br />designated Floodplain Administrator from either Weld County or the City of Ft. <br />Lupton prior to mining. All river banks on the east side of the South Platte River <br />on this site and further onto the point bar at the western edge of the site are <br />heavily rip -rapped with large chunks of concrete. Flooding in this area of the <br />South Platte River in September 2013 and again in May 2015 did not affect this <br />property. <br />Earthwork <br />Earthwork will generally occur as indicated in Table 6.4.4-1. Sand and Gravel <br />extraction will follow stripping of areas of each mining cell. Reclamation will occur <br />concurrently wherever possible. <br />Slurry Wall Construction <br />A soil / bentonite slurry wall will be constructed surrounding the perimeter of the <br />mine area as shown on Exhibit C-2. The applicant intends to complete a slurry <br />wall engineering design prior to construction. The slurry wall engineering design <br />will be submitted as a technical revision to this permit prior to construction. The <br />slurry wall is expected to be approximately 3-4 ft wide and extend into bedrock to <br />a depth specified by the final design. To protect the stability of the slurry wall, pit <br />slopes will be mined at 2H:1 V and the top of slope will be offset 10 ft from the <br />inner edge of the slurry wall. A 25 ft setback has been specified from the top of <br />July 2015 Chavers Mining Resource <br />Regular 112 Permit Application <br />