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Coulson Eacsvating Company, loc. - Bouser Gravel Pit Ezbibit E - Reclamation Pfau Reclamation will entail the construction of a lined water storage reservoir developed water resource covering approximately 65 acres with a potential storage volume of 1562 acre-ft (see Exhibit F). The backslope of the reservoir berm and overburden storage areas will be seeded with a native grass mixture. Apre-existing pond will also remain in the southwest corner of the permit area. This pond was constructed in 1976 by Larimer County. Surrounding Land Use Primary land uses near the vicinity of the mine include farming, transportation, tural residential, and recreational. A county road and raihoad are located north of the proposed mine, and two pazcels of land, owned by separate landowners, are located to the northeast. These parcels aze used for rural residential and agricultural purposes, as well as the land directly to the west. The Big Thompson Reservoirs State Wildlife Area and Big Thompson River corridor are located directly to the south of the proposed mine, and the Big Thompson River corridor continues along the eastern project boundary. Reclamation Sequence Reclamation will begin after the entve permit area has been mined. Please see Exhibit D, Mining Plan for timetables. Following aggregate extraction, approximately 215,914 yd3 of weathered Pierre shale will be ripped from the pit bottom and stockpiled adjacent to the borrow area. The slopes of the mined pit will then be backfilled with 130,605 yd3 of overburden, at a 2:1 slope, creating a stable substrate for the reservoir liner. Approximately 74,864 yd3 of the remaining stockpiled overburden will be shaped into a trapezoidal berm measuring 8-16 ft in height, 49.5 ft wide at the base, and 10 ft wide at the top, with 2:1 side slopes. The top of the dam will be at a constant elevation of 4864 ft. The berm and fill slopes will be contiguous. Subsequently, the entire mined pit plus the berm slope will be lined with weathered Peirre shale. The resulting area will be used as a reservoir for water storage purposes. Re-vegetation of the areas utilized for extraneous overburden replacement and the slope on the backside of the berm will occur after construction of the reservoir liner. See Exhibit F for reservov contours. Coulson Excavating is currently negotiating with Front Range municipalities to lease the reservoir to the city for water storage. The division will be updated on this deal as it materializes. Reservoir Liner Design and Specification The purpose of this section is to provide design specifications for the reservov liner. The goal is to design apost-mining, compacted clay liner that will prevent groundwater leakage into the reservoiv, at a rate Beater than or equal to .03 ft3 /day / ft The source for the compacted clay liner will be weathered zone of Pierre shale occurring an average of 26 ft. below ground surface. Textually and mineralogically continuous in a lateral direction, the Pierre shale is flat lying in this area (Porter, 1976). The weathered zone is a friable silty clay consisting of illites and small amounts of smectites (Gill et al, 1996). Source Material Sam~neJLaboratorv Analysis A 5-gallon sample of weathered Pierre shale was collected from a gravel operation to the west. Collected from the upper 3 to 4 ft. of the weathered horizon, the shale appeazed very consistent with respect to color and texture with that of the weathered shale within the proposed excavation