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LAFARGE <br />NORTH AMERICA <br />Construction Materials <br />I5. Page 24 of 81 of Exhibit G and Table 1 by AMEC indicate that 13 wells are within 600 <br />feed of the site, with 2 potentially impacted, and the "Groundwater Monitoring Plan " <br />states 20 wells are within 600 feet with 6 potentially impacted. <br />The inconsistencies among the "Groundwater Monitoring Plan," Exhibit G, and Table 1 have <br />been corrected to show the same number of potentially impacted wells. The "Groundwater <br />Monitoring Plan" was drafred prior to the engineered groundwater model. <br />16. Based upon the strong potential for ground water impacts from dewatering 121arge open <br />pits and lining three pits, additional monitoring wells will need to be selected and/or <br />installed to ensure compliance with Rule 3.1.6(1). The applicant must also provide a list <br />or table showing Well Permit numbers and constructed depths for all the monitoring <br />wells. <br />Lafazge has installed 30 monitoring wells within the amendment boundary which aze monitored <br />under a cleazly defined ground water monitoring plan. The groundwater model has illustrated <br />azeas with potential for impact; Lafarge currently has monitor wells in each of these locations. <br />Monitor wells DS03-MWOS and DS03-MW06 are located in the immediate vicinity of well <br />number 2216, which has been identified as low risk for impact during mining activities. <br />Monitor wells DS03-MWOS and DS03-MW06 are also located in the immediate vicinity of well <br />number 13697, which has been identified as high risk for impact during mining activities. These <br />monitor wells aze adequate for monitoring the areas of concern identified in the groundwater <br />model. Upon commencement of mining at the site, the monitor well measurements will be <br />assessed to validate the groundwater model If inconsistencies exist or neazby landowners <br />experience impacts, the quantity and location of specific, additional monitor wells will be <br />accurately identified. The installation of additional monitor wells, if necessary, will be most <br />beneficial once mining has begun and locations can be appropriately selected based on need. <br />17. Once the monitoring well quantities and positions are deemed adequate by the Divisor, <br />to establish baseline ground water levels, monitoring frequency for ground water levels <br />in the monitoring wells will need to be increased to monthly. One full year of monthly <br />data will need to be collected and reported prior to beginning mining. The data <br />submitted with the application is inadequate infrequency and extent of monitoring wells. <br />A technical revision will be required to reduce the frequency. <br />As stated in question 16, Lafarge has installed 30 monitoring wells within the amendment <br />boundary, which are monitored under a clearly defined ground water monitoring plan. Lafazge <br />understands the Division's concerns pertaining dewatering during the mining operations and <br />potential impacts to neighbors. Lafarge has utilized over 5 years of groundwater level data and <br />developed a groundwater model that has calculated azeas with potential for impact. As stated in <br />response to question 16, Lafazge currently has monitor wells in each of these locations. The <br />results of the study have shown that monitor wells DS03-MWOS and DS03-MW06 are located in <br />LAFARGE NORTH AMERICA INC. -Lafarge Aggregates, Concrete & Asphalt <br />10170 Church Ranch Way, Suite 200 Westminster, Colorado 80021 <br />Telephone: (303) 657000 Facsimile: (303) 657037 <br />