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Coulson Ezcavating Company, Inc. - Bonser Gravel Pit Ezhibit D -Mining Plan Water Diversioav and Impoundment A trench dug at the tce of each cell wall will expose groundwater, which will be pumped to a sediment pond located at the southwest corner of the permitted area (see Figure 1, Exhibit E). The current irrigation system consists pipe setting in the surface for sprinkler irrigation. Coulson Excavating Company, Inc is the owner of the system. The piping will be disassembled prior to mining. The irrigation system will not be re-installed after mining is complete. Nature of the Overburden, Gravel Deposit, and Undertyiug Stratum The overburden consists of fine sand and silt, specifically Table Mountain Loam, Table Mountain Saline, and Nunn Clay-Loam soils with slopes ranging from 0 - 3%. Their thickness does not exceed 3 yards (9 ft). The gravel deposit is classified as Class A aggregate (Schwcehow et al. 1974), and has an average thickness of 7.3 yds (22 ft). Underlain by the gravel is a zone of weathered Pierte shale, followed by Pierre shale. Overburden and Weathered Shale Stocl~iles The maximum volume of overburden (topsoil + subsoil) to be stockpiled at any given time is about 687,327 yds. The stockpile surrounding the permit azea will measure 6,749 ft long, 20 - 30 ft high, and 40 - 50 ft wide, with 0.5:1 side slopes (see Figure 1, Exhibit D). Overburden placed at the northern end of the project area will have a height no greater than 40 ft. Best Management Practices (BMP's) will be utilized to protect the stockpiles from wind and water erosion. These practices will include a silt fence placed along the tce of the stockpiles, and vegetation of the stockpiles. Moreover, the berms will be watered two times daily before vegetation is established to ensure minimal erosion. About 74,864 yd~ of overburden will be utilized for the reservov berm following mining. The berm will measure 49.5 ft wide at the bottom, 10 ft wide at the top, and 9.9 ft in height, with 2:1 side slopes. All additional overburden not used for reclamation purposes, which will total approximately 481,858 ydl, will placed in the north portion of the project boundary. The total area that will be utilized for this purpose is 178,944 sq ft (4 acres). The total volume of shale to be stockpiled at any one time is approximately 215,914 yd3. Please see Exhibit E for details regarding handling of the shale stockpile. Intended Use of Eztracted Commodities The sole commodity to be extracted from the mine is gavel, which will be processed and used for asphalt hot mix and raw road base. Asphalt Batch Plsnt Petroleum products located in the proposed asphalt batch plant will be diesel fuel and liquid asphalt petroleum. These substances will be stored in above ground storage tanks or within the plant itself. Little risk exists of soil and/or groundwater contamination in the event of an asphalt spill, due to its high viscosity. However, if a diesel spill measuring over the specked reportable amount occurs, the