PERMFILE109009 - Laserfiche WebLink

Home Browse Search

Coulson Excavating Company, Inc. -Stroh Gravel Pit Exhibit D -Mining Plan No relocation will take place. Water rights associated with the ditch will be utilized to supplement groundwater lost during mining. 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 eastem borders of the permit boundary and within each mining cell as needed. Stockpiles will measure approximately 50-f1 wide and 20-ft high with 0.5:1 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. No more than approximately 340,000 yd3 of stockpile material will occur at any given time. 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 Maximum Cell Depth Graded at a 1:1 slope, each cell will have a vertical depth of 25 fl. Coulson Excavating will maintain a setback of 40 ft from the permit boundary (as measured from the toe of the pit slope) along the eastem, westem and southem boundaries, and 125 ft from the permit boundary (as measured from the toe of the pit slope) along the northern boundary. Asphalt Batch Plant An asphalt plant will be placed near the northwest corner of Ce113 in the south zone at an appropriate location and time (i.e., when that area has been mined out) to start the processing of asphalt.