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encountered in well MWOO1A in subsequent sampling events. During the March, 20, 2012, <br />1.5 feet of water was measured in the well, which is essentially water filling the silt cap at <br />the bottom of the well. It has been determined that water in this well is sourced by <br />formation condensation. The well is 100 feet deep. Samples were not collected from well <br />MWOO1A. <br />During the second quarter 2008, GCC installed an additional shallow groundwater <br />monitoring well (MW005) at a location between the mine plant operations and the St. <br />Charles River (shown in Figure 1). The new well location was selected with input from the <br />DRMS. Groundwater was not encountered in the shallow aquifer at the time the well was <br />installed, and no sample was collected. The well was sounded during the second half 2008 <br />monitoring event, and was found to be dry, and no sample was collected. The well has <br />been sounded during the 2009, 2010, and 2011 semi -annual sampling events, with similar <br />results. During the March 2012 sampling, this well was determined to be dry. No sample <br />was collected at MW005. <br />Depth-to- groundwater measurements were performed at each alluvial well prior to <br />sampling. Wells were also sounded to determine total depth. The volume of standing <br />water in each well was determined Each of the alluvial wells were purged using a new <br />disposable poly bailer. A minimum of three casing volumes was purged from each well <br />prior to sampling. Field parameters pH, conductivity, and temperature were recorded as <br />each well volume was removed. Groundwater was purged until these parameters were <br />stabilized and reproducible (typically after three or five measurement sets). <br />Water levels measured in each of the alluvial wells had risen slightly from the low levels <br />found during October 2011. The St. Charles River was flowing approximately 10 cubic <br />feet per second during this March 2012 site visit, where no surface flow was observed in <br />the river during the October 2011 event. Each of the alluvial wells has historically <br />produced significant water while bailing, though only 0.3 feet of saturated alluvium was <br />noted at well MW -3 during the October 2011 sampling event. During the March 2012 <br />event, water levels had recovered somewhat, such that all sample bottles were easily filled. <br />All groundwater samples were submitted to Accutest Laboratory, located in Wheatridge <br />Colorado, for analysis of TDS and sulfate. Accutest subcontracted analyses for <br />radiochemical parameters (radium 226 and radium 228) to Hazen Research laboratory, <br />located in Golden, Colorado. <br />RESULTS AND DISCUSSION <br />Results of the March 20, 2012 groundwater sampling are provided in Table 1. Historical <br />results for the compliance suite for all wells are shown in Table 2. Table 2 also presents the <br />average and standard deviation statistics for each parameter based on the monitoring history <br />for each well. Figure 2 presents time versus concentration plots for the four GCC <br />monitoring constituents of concern, with NPL noted. Analytical results provided by the <br />contract laboratories are presented in Appendix A. <br />3 <br />