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INTRODUCTION <br />Contour Consulting Engineering, LLC, (Contour) collected groundwater samples at the <br />GCC Rio Grande, Pueblo Cement Plant, on September 26, 2012. The samples were <br />collected to satisfy monitoring permit requirements, as stipulated by the Colorado Division <br />of Mining Reclamation and Safety (DRMS). Quarterly sampling was initiated in 2008. <br />Beginning in 2009, sampling was set at a semi - annual monitoring frequency. Due to <br />increasing trends for total dissolved solids (TDS) noted in the alluvial wells over the last <br />two monitoring events, quarterly sampling has been re- initiated. <br />The compliance suite for the St Charles River monitoring wells now includes sulfate, TDS, <br />radium 226, and radium 228. Sampling events previous to October 2011 included a <br />comprehensive list of dissolved metals, anions, cations, and additional radiochemistry <br />parameters. As part of recent semi - annual monitoring reports submitted to the Division, a <br />reduced sampling suite more appropriate for the site was approved, based on <br />comprehensive analysis of the results from the larger sampling suite over the sampling <br />history for the project. Unless conditions at the site change, the new suite of monitoring <br />parameters will be used in all future monitoring events. <br />The previous sampling events, performed in October 2011, March 2012, and June 2012 <br />indicated that TDS concentrations exceeded the Numeric Protection Level (NPL) of 2,630 <br />mg/L at wells MW -03 and/or MW -04. Therefore, additional sampling was performed for <br />TDS only in September 2012. <br />WORK PERFORMED <br />On behalf of GCC, Contour Consulting attempted to collect groundwater samples for <br />analysis of TDS only from three shallow alluvial monitoring wells (MW -02, MW -03, and <br />MW -04) on September 26, 2012. Depth -to- groundwater measurements were performed at <br />each well prior to sampling. Wells were also sounded to determine total depth. Well MW- <br />03 was dry, as was the St. Charles River adjacent to the well, therefore, no sample could be <br />collected at MW -03. <br />For wells MW -02 and MW -04, the volume of standing water in each well was determined. <br />Each of the alluvial wells were purged using a new disposable poly bailer. A minimum of <br />three casing volumes was purged from each well prior to sampling. Field parameters pH, <br />conductivity, and temperature were recorded as each well volume was removed. <br />Groundwater was purged until these parameters were stabilized and reproducible (typically <br />after three or five measurement sets). <br />All groundwater samples were submitted to Accutest Laboratory, located in Wheatridge <br />Colorado, for analysis of TDS. <br />2 <br />