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8. Groundwater <br /> Groundwater is located approximately seven feet below the surface of the ground onsite. This is <br /> known from Elam's experience in mining adjacent areas in the same deposit and alluvial aquifer. <br /> No wells are located within 600 feet of the proposed pit. The nearest approved well is in fact the <br /> gravel well permit for the mining activities (23 Road Pit)to the west of the site. It can be seen on <br /> Map C-1. <br /> 8.1 Groundwater—Mining <br /> Mining activity will expose groundwater from the very beginning of operations. Dewatering of <br /> the pit will take place to bring the groundwater table below the operating floor. This allows <br /> equipment to safely and effectively mine the alluvial deposit. The pit pump will be active <br /> continuously during the mining season, which typically is mid-April to early-November, <br /> depending on weather. The pit pump will not run during flood events or when temperatures drop <br /> below freezing. <br /> 8.1.1 Area 1 <br /> Pit dewatering will intercept groundwater from the alluvial aquifer of the Colorado River that is <br /> onsite and route it back towards the river via the Wilsea Drain. This process is common among <br /> sand and gravel pits along the rivers and waterways of Colorado. The layout of the dewatering <br /> process can be found on Map C-3, including the typical location of the pit pump, its typical <br /> installation, and dewatering path to Wilsea Drain via the sediment pond. The pit pump will be a <br /> mobile pump with and accompanying diesel generator. This generator will have an onboard fuel <br /> tank with secondary containment. It will typically be located at the southwest end of the pit, <br /> closest to the sediment pond. The pump will be located,typically,two feet below the active pit <br /> floor. It will also be surrounded by a gravel filter. This configuration minimizes the amount of <br /> sediment that is collected by the pumped water. <br /> The sediment pond will take water from the pit pump and allow settling time to remove <br /> remaining sediment. Water will then discharge from the sediment pond via a pipe to the Wilsea <br /> Drain to the north. This system of dewatering is proven to move the water out of the way of <br /> mining operations while trapping sediment on site. <br /> 23 114 West <br /> July 2020 Ci-6 Gnu l cwicAi and Assoriatm PI,L(' <br />