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04004 Banks and Gesso, LLC <br />known to have been adversely affected by the existing Fort Lupton mine, which has <br />been in operation since 2001. <br />Possible Impacts on Water Resources <br />Mining will occur in phases. In most cases, a slurry wall will be constructed around each <br />phase prior to mining. In some cases, a clay liner will be constructed during mining. The <br />slurry wall will be keyed into bedrock to hydraulically disconnect the mine from the <br />groundwater system. The clay liner would be constructed as mining progresses, sealing <br />along the way. In both cases, mining will occur in the "dry' inside of each phase so that <br />no impacts to groundwater are anticipated. It should be noted that mining has occurred <br />for three years at the Fort Lupton operation within a slurry wall with no known impacts on <br />groundwater outside of the pit. <br />The applicant has initiated a groundwater monitoring program. Sixteen piezometers <br />were installed around the proposed amendment area in March 2004 for this program <br />(See the following map Exhibit G: Monitor Well Locations). These piezometers will be <br />read monthly for at least one year. The data will be used to establish pre-mining <br />groundwater levels adjacent to the amendment area that can be used to determine any <br />impacts from mining in the future. It is anticipated that a process will be defined to <br />assess when any changes in groundwater are due to mining, and measures that may be <br />used to alleviate any effects. <br />There will not be any significant effects on surface water from the proposed amendment <br />area. Little Dry Creek and the East Lateral of the Lupton Bottoms Ditch will not be <br />mined, and mining will be set back at least 25 feet from these features. The South Platte <br />River flows to the east of the amendment area and will not be affected, as mining will be <br />set-back at least 200 feet from the current riverbank. The proposed mining will not <br />reduce the flood conveyance capacity of the 100-year flood plain so that it will not cause <br />a rise in the floodplain. <br />Water Requirements <br />Water will be used for dust control, aggregate processing, and concrete production. <br />Water will be obtained from the existing well, which is located south of the slurry wall and <br />is used for the current operation. It is assumed that all diversions from this well will be <br />fully consumptive and will be replaced. <br />Water will be lost from dust control, aggregate processing, concrete production, and <br />exposed water surfaces. Exposed water surfaces include: lined settling ponds, a <br />dewatering trench and settling ponds (mine pits will be kept dry so that fhere will be no <br />evaporation from them). <br />A Substitute Water Supply Plan (Plan) was submitted to the State Engineer's Office <br />(SEO) and was approved on September 12, 2001. An updated Plan for the mining area <br />was approved by the SEO in June 2004. As described in the updated Plan, all depletions <br />from mining will be fully replaced by two sources of augmentation water -Lupton Bottom <br />Ditch shares during the irrigation season and winter water leased from various sources <br />for the remainder of the year. The Plan will be operated according to any terms and <br />Fort Lupton Sand and Grave! Mine - L.G. Everist, Inc. September 20, 2004 <br />Amendment to Permit No M-1999-120 Page 15 <br />