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Wome Office Well Monitoring Report <br />1.0 Introduction <br />1.1 Scope and Purpose <br />This report presents the results of a well monitoring program instituted by Lafarge West, Inc. <br />with the approval of the State of Colorado Division of Minerals and Geology (DMG) and Larimer <br />County. The monitoring program was developed in response to concerns about groundwater <br />levels relative to an approved gravel mining operation at the North Taft Hill Expansion Site on <br />LCR 19 north of Fort Collins, Colorado. The program seeks to establish baseline groundwater <br />levels in the vicinity of the site prior to the start of dewatering activities associated with the <br />mining operation. This baseline will be compared to data collected during the life of the <br />operation to determine if any significant changes to groundwater levels have occurred. <br />Statistical analysis is performed as part of the program to objectively evaluate the data sampled <br />monthly from the established wells. The analysis will attempt to isolate changes in the <br />groundwater table associated with mining activities from those associated with seasonal <br />fluctuations and river flows. The result of this analysis is compared to qualitative information <br />goals to establish whether any mitigation by Lafarge West is necessary to offset negative <br />impacts to constituents due to mining activities. <br />1.2 Project Location and Description <br />Eleven monitoring wells surrounding the North Taft Hill Expansion site at varying distances <br />have been established for taking measurements associated with the monitoring program. <br />These wells have either been modified for this use or driven specifically for this purpose, <br />generally consisting of 2" PVC tube with a perforated end piece. Figure 1 is a map showing the <br />location of these eleven wells. <br />Measurements have been taken for groundwater elevation, conductivity (a measure of <br />dissolved solids) and pH (a measure of acidity) at each well. Groundwater elevation is <br />measured monthly; conductivity and pH are measured quarterly. Results are reported annually <br />except in the case of a significant change. <br />1.3 Information Goals <br />The primary goal of the monitoring program is to determine within a certain confidence level <br />what the groundwater condition was before mining begins and what it is like after mining has <br />commenced, and whether the difference is significant. This has two ramifications. The first is <br />the ability of neighbors to legally use groundwater at the same rate and quality as they had prior <br />to the start of mining. The second is expressed by DMG regulations requiring the operator to <br />minimize "disturbances to the prevailing hydrologic balance of the affected land and of the <br />surrounding area and to the quality and quantity of water in surface and groundwater systems, <br />both during and after the mining operation and during reclamation." <br />To determine whether either of these two conditions has been violated requires a combined <br />effort of qualitative and quantitative approaches. Statistical analysis can determine whether a <br />significant change has taken place. Reporting from well owners regarding the ability to pump at <br />TST, INC. CON5V LTIN6 ENGINEERS <br />Page 1 <br />