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Coulson Excavating Company, Inc. -Stroh Gravel Pit Exhibit D -Mining Plan Nature of the Overburden, Gravel Deposit and Underlying Stratum The overburden consists of fine sand and silt, specifically Fluvaquents (33), Loveland Clay Loam (64), Paoli Fine Sandy Loam (81) and Table Mountain Loam (105), each with slopes ranging from 0- 1%. The overburden thickness is assumed to average approximately 6 ft in the north zone of the pit and 8.6 ft in the south zone. The gravel deposit is classified as Class 1 Aggregate (Schwochow et al. 1974) and is assumed to have an average thickness of approximately 17 ft throughout the pit. Underlain by the gravel is approximately 3 - 6 ft of weathered Pierre shale. Refer to Exhibit C for details. Topsoil and Overburden Stockpiles The average volume of overburden to be stockpiled for each cell in the south zone is approximately 322,156 yd3. Overburden will be stockpiled around the southern, western and eastern borders of the permit boundary and within each mining cell as needed. Stockpiles will measure approximately 50-ft wide and 20-ft high with 1:1 side slopes. Best Management Practices (BMPs) will be utilized to protect the stockpiles from wind and water erosion. These practices will include a silt fence placed along the toe of each stockpile and vegetation of the stockpiles themselves. Moreover, the berm will be watered two times daily before vegetation is established to ensure minimal erosion. See Exhibit D -Mining Plan for details. Each cell in the north zone will be stripped of approximately 15,578 yd' of overburden, which will be stockpiled along on the perimeter of each annual cell. The stockpiles will measure approximately 35-ft wide and 6-ft high. Intended Use of Extracted Commodities The sole commodity to be extracted from the mine is gravel, which will either be sold to other aggregate users or processed and used for asphalt hot mix and raw road base. Pit Setback and Maaimum Cell Depth Graded at a 1:1 slope, each cell will have a vertical depth of 25 ft. Coulson Excavating will maintain a setback of 100 ft from the project boundary (as measured from the toe of the cell wall), and 140 ft from the Big Thompson River (as measured from the toe of the cell wall to the near edge of the river). In addition, an 8-inch diameter, steel, high-pressure, liquids petroleum pipeline, located beneath the ground surface, exists at the project area (See Exhibit C). Per agreement with the owner, Kaneb Pipeline Company, Coulson Excavating will maintain a setback of approximately 50 ft to the west and 50 ft to the east of the buried pipeline as measured from the top of the mining cell to the centerline of the petroleum pipe (See Exhibit S - H:\Stroh\word\DMG\working Exhibit D.doc