2021-09-09_REVISION - M2004044 (10)

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South Platte River (see Exhibit C Mining Maps). As excavation begins, the mining cell and dewatering trenches on the floor will continue to collect any water entering the lined Areas, keeping the deposit material relatively dry. The collected water will be directed to settling ponds within the Areas or near the final discharge point to South Platte River. It is anticipated that dewatering will be completed within the slurry wall lined mining area within 12 months and dewatering throughout the life of the mine will be limited to precipitation, stormwater runoff that drains into the mining area, and minor amounts of groundwater. Earth Moving Setbacks from the top of slope of each area to the proposed permit boundary or man- made structures not owned by the applicant or by agreement with the structure owner will generally be 30 feet or greater. Specific setbacks from Highway 7 and Tucson Street also account for future expansion of the roadways. The perimeter setbacks from the structures are shown on Exhibit C - Mining Maps. These setbacks were determined in combination with Adams County regulations and the Slope Stability Analysis prepared by Tetra Tech provided herein in the Geotechnical Stability Exhibit. The setbacks reflect the Factors of Safety in the Proposed Slope Stability/Geotechnical Analysis Policy in the DRMS memorandum dated May 16,2018. Areas to be mined will be prepared by removal of topsoil and overburden. Each preparation area may be as much as 100 feet wide along the anticipated mining face. Usually, only enough area is stripped and prepared to provide the estimated needs for the next 10 to 14 months of mining. Surface topsoil material will be stripped separate from the underlying, deeper subsoil or overburden material. This topsoil layer contains most of the soils organic matter and will be stockpiled separately for use in reclamation. Once the topsoil has been removed, the rest of the overburden will be stripped and stockpiled separate from the topsoil. When the alluvial material is exposed and sufficiently dewatered, the aggregate material will be recovered using equipment typical for sand and gravel mining operations. In the West and East Areas, the aggregates will be mined using conventional dry mining methods. Earth moving equipment may include, but is not limited to, dozers, loaders, scrapers, and excavators as mining progresses to a depth of 20 to 50 feet below the surface. The alluvial material is an unconsolidated deposit and, therefore, no blasting is required. The aggregate material from the Areas will be temporarily stockpiled within the various Areas, conveyed to the staging area, or immediately transported off-site for processing. During mining and reclamation activities, watering trucks for dust control will be used as needed. Aggregate Industries—Tucson South Amendment—MLRB 112 Permit Application Exhibit D-5