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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, 2011, and 2012 sampling events, with similar results. <br />During the June 2012 sampling, this well was determined to be dry. No sample was <br />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 have 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. There was slightly more flow in the river during <br />June 2012 than was noted in March 2012. 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 -03 during the October 2011 sampling event. During the June 2012 <br />event, water levels had recovered, with 1.4 feet of water in well MW -03, such that all <br />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 June 21, 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 NPLs noted. Analytical results provided by the <br />contract laboratories are presented in Appendix A. <br />All samples were submitted for analysis of sulfate, TDS, radium 226, and radium 228. The <br />results of these analyses are discussed in the following sections. <br />3 <br />