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OCT-30-2001 TUE 02 ~ 54 PM BANKS ~ GESSO LLC FAX N0. 303 ~ 8329 P. 06 If water is required for operational purposes, the Applicant will obtain a hydrant permit from the South Adams County Water and Sanitation District. Because of 90 percent recycle, make up water will be required at a rate of approximately 5 to 10 gallons per ton. The Applicant is uncertain at this time how much on-site washing will take place. If half of the mine's estimated resources (500,000 tons) are washed, operational water requirement will approximate 1 million gallons per year. Water rights to augment out-of-priority depletions of groundwater are being secured by the Applicant from the Consolidated Mutual Water Company, which owns rights to the discharge from the Motro Wastewater Reclamation District's York Street facility. 15. As required by Rule 6.4.7(b), please identity all known aquifers that maybe directly or indirectly affected by the proposed mining and reclamation activities at the 124`" Estates mine operation. The applicant should also Characterize the geology and depths of the aquifers as well as pertinent aquifer characteristics, i/known. The location for the proposed mining activity lies within the broad alluviated South Platte River Valley. Unconsolidated sediments of approximately 40 feet in thickness overlie bedrock. Water within the unconsolidated and unnamed aquifer is derived from infiltration of precipitation, leakage from streams and surface impoundments, and from infiltration of irrigation water. In the area of the mine, water levels are typically 20 to 30 feet below the ground surface, indicating a saturated aquifer thickness of 10 to 20 feet. Colorado Division of Water Resources records show only four wells, located within 600 feet of the site, placed within this shallow unconsolidated aquifer. State records show that three of these wells are monitoring wells permitted to the Phillips Petroleum Company. The fourth well, located approximately 400 feet northwest of the proposed mining area, is described in State records as being for domestic use and shown to have a total depth of 46 feet with water appearing at 29 feet below ground surface. Water level fluctuations within the shallow aquifer in the area of the mine are generally small, less than 6 feet, and seasonal, reaching a high in the spring and declining to a low in the fall, with minimal long term trend. Groundwater flow direction is to the northwest, Transmissivity in the area of the mine is less than 50,000 gallons per day. (S.G. Robson, U.S. Geologic Survey Atlas HA-736, Geohydrology of the Shallow Aquifers in the Denver Metropolitan Area, Calorado, 1996 and R.T. Hurr and others, U.S. Geologic Survey Open File Report 72-332, Hydrogeologic Characteristics of the Valley-Fill Aquifer in the Brighton reach of the South Platte River Valley, Colorado, 1972) 16. The applicant states on Page 16 that dewatering maybe temporarily lower adjacent ground water levels during initial phases of mining. In accordance with Rule 6.4.7(2)(b), the Division requests that the applicant define or predict the cone of depression expected for arty areas to be dewatered artd dry mined during the fife of the operation. The cone of depression assessment should define, at a minimum, the horizontal and vertical extent of drawdown expected. If during the assessment, the applicant determines that a drewdown will occur offsite that may impact a current groundwater user, the applicant should explain any mitigation measures to be implemented and trigger points that would put mitigation measures into effect. Records of the State Division of Water resources show only one well, used for domestic purposes, within 600 feet of the proposed mining area, placed within the shallow, unconsolidated aquifer of the area. This well is located approximately 400 feet to the