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0 4 Facility Description <br />4.1 Design Concepts <br />The Site has been mined for sand and gravel, and in its current condition is not conducive <br />to using the land for future development other than water storage. AFS has been in the <br />inert materials disposal business for over 20 years and has the experience to safely and <br />efficiently fill the Site. Inert materials and potentially fly ash (as approved by CDPHE <br />and Adams County) will be used to fill the Site. The fill is planned to have a Certificate <br />of Designation from Adams County for the inert filling activities. The fill area is large <br />with an estimated fill volume of ± 1.5 million cubic yards and the facility is expected to <br />be in operations for 15 to 30 years. The area filled is all below grade and will bring the <br />Site up to elevations that may be usable in the future for development. An advantage to <br />this Site and its specific CD is that the land is reclaimed and the inert materials are not <br />sent to, and using valuable airspace at, a typical municipal solid waste disposal facility. <br />The Frei - Henderson Inert Fill Site has the following characteristics: <br />• Lined with a compacted clay liner <br />• No putrescible waste will be placed <br />• No typical municipal solid waste will be placed <br />• No methane generation from decaying organic matter <br />• No construction demolition debris <br />• Inert fill materials only (and fly ash as approved) <br />The Frei - Henderson Inert Fill Site is being lined with a compacted clay liner to limit any <br />water infiltration from adjacent areas and to segregate the inert materials from native <br />ground. If approved, fly ash will be placed in the inert fill in certain areas to minimize <br />the future ground surface settlement. <br />The fly ash approval will be an addendum to the permit application given approval of <br />Adams County and CDPHE for the specific manner described. The fly ash would be <br />mixed with inert materials and water to obtain an optimum compaction and the lowest <br />leaching potential of metals in the fly ash. Similar operations of mixing soils with fly ash <br />have been successful in Adams County. A method consistent with the others approved in <br />Adams County would be utilized at the Frei - Henderson Inert Fill Site. Fly ash will be <br />placed at a sufficient distance below the final grade to prevent excavation of the fly ash <br />with future development of the property and installation of utility lines. The minimum <br />distance of 15 feet below the top of the inert fill will separate fly ash from the surface. <br />The fly ash received will be mixed as it is placed to achieve the maximum compaction <br />and structural stability as described in the addendum to this plan. An optimum mixture <br />ratio for the fly ash and soil will be done according to the geotechnical analysis done to <br />demonstrate the optimum mixture and moisture. The mixture will be analyzed to <br />AFS Frei-Henderson Inert Fill Page 9 of 23 <br />MOLEN &. ASSOCIATES, LLC