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Mr. Tom Schreiner, Division of Minerals and Geology v~ <br />March 23, 2005 CIVIL RES~URCES,LLC <br />Page 7 <br />reporting of data to the Division, number and location of monitoring wells o~ peizometers, "Nigger" <br />for determining when a significant hydrologic impact has occurred, and mitigation measures to be <br />employed in the event of a trigger. Please respond. <br />The applicant has monitored onsite groundwater levels every month since June 2004. Additional offsite <br />piezometers were installed in March 2005 and are included in monthly monitoring that will continue during <br />the duration of mining and reclamation. Quarterly water level reports will be sent to the Division upon <br />request. Presently there are 15 monitoring locations, 9 onsite and 6 offsite (refer to Well Location and <br />Hydrologic Features Map for locations). Fluctuations greater than two feet below annual low levels will be <br />used as a "trigger." Since mitigation measures will be implemented prior to exposing groundwater the <br />potential for the "trigger" to occur should be minimal. <br />16. In conformance with Rule 3.1.6(1), please characterize the response of the aquifer in the affected <br />land and surrounding area during final reclamation, le: completion of liner installation for all three <br />(3) water storage cells. Such characterization will need to include the expected now path of regional <br />groundwater movement, the "mounding effect" expected on the up-gradient side of the lined cells, <br />and the "shadowing effect" expected on the down-gradient side of the lined cells. Such <br />characterization will need to include the vertical and horizontal extent of changes to the existing <br />now patterns of alluvial groundwater movement in the area to be excavated. Such characterization <br />will need also need to include an assessment ofimpacts to any existing structures (such as <br />Colorado Highway 85) or water features in the surrounding areas of the lined water storage facilities. <br />Please respond. <br />The effects of lining the parcels with a compacted clay liner were modeled and are discussed in Section 4.3 <br />of the Groundwater Model. Figure 13 of the Groundwater Model Report presents the mounding and <br />shadowing affects of placing the liner material in the aquifer. Maximum mounding of approximately 3 to 4 <br />feet was predicted by the model on the eastern and southeastern margins of the site. Since groundwater is <br />on the average 25 feet below existing grade this mounding effect of the groundwater table will only increase <br />the water surface so that the groundwater level is approximately 21 feet below the existing ground surface. <br />Shadow effects, as discussed in the Groundwater Model Report Section 4.3, were predicted by the model to <br />drop a maximum of 0.9 feet. Therefore, groundwater levels under Highway 85 might decrease slightly. <br />17. In conformance with Rule 3.1.6(1), please describe mitigation measures that will be employed to <br />minimize the permanent affects to the alluvial aquifer and surrounding area as described in Item 15 <br />above. <br />No permanent mitigation measures are required or proposed. Please refer to Commenf }5 above and <br />Section 4.2.1 of the Groundwater Model. <br />18. In conformance with Rule 8.4.7(3), please revise the estimate of project water requirements to <br />include the volume of water tied up in the pit run material, the volume of water needed for washing <br />operations, and the volume ofmake-up water needed for washing operations during the mining <br />phase of the operation; and the volume of water needed to fill the three (3) reservoirs to maximum <br />storage capacity during final reclamation. Please provide. <br />The Table presented below discusses the operational losses (water lost to washing aggregate, dust <br />suppression, etc.). The Office of the State Engineer (OSE) has the responsibility and jurisdiction for <br />