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INTRODUCTION <br />Contour Consulting Engineering, LLC, (Contour) collected groundwater samples at the <br />GCC Rio Grande, Pueblo Cement Plant, on June 21, 2012. The samples were collected to <br />satisfy monitoring permit requirements, as stipulated by the Colorado Division of Mining <br />Reclamation and Safety (DRMS). Quarterly sampling was initiated in 2008. Beginning in <br />2009, sampling was set at a semi -annual monitoring frequency. Due to increasing trends <br />for total dissolved solids (TDS) noted in the alluvial wells over the last two monitoring <br />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, <br />GCC has recommended that the reduced sampling suite would be appropriate for the site. <br />This recommendation was based on comprehensive analysis of the results from the larger <br />sampling suite over the sampling history for the project. Unless conditions at the site <br />change, the new suite of monitoring parameters will be used in all future monitoring events. <br />The previous sampling events, performed in October 2011 and March 2012, indicated that <br />TDS concentrations exceeded the Numeric Protection Level (NPL) of 2,630 mg/L at wells <br />MW -03 and MW-04. NPLs were set by the DRMS in a December 8, 2009 letter to GCC. <br />The December 8, 2009 letter states, "If an upward trend, above set limits is noted, the <br />frequency of sampling will increase to quarterly." Both TDS exceedences at wells MW -03 <br />and MW -04 were preceded by downward trending TDS results between the October 2010 <br />and April 2011 sampling events, and GCC noted that no upward trends were present. <br />Regardless, DRMS submitted a letter to GCC dated February 24, 2012, indicating that, due <br />to the TDS exceedences, quarterly sampling would resume. <br />WORK PERFORMED <br />On behalf of GCC, Contour Consulting collected groundwater samples from three shallow <br />alluvial monitoring wells (MW002, MW003, and MW004) in the vicinity of the St. Charles <br />River on June 21, 2012. The alluvial wells represent downgradient conditions with respect <br />to the Cement Plant operations. Deep well MWOO1A is completed in the Codell Sandstone <br />west of the plant. This well was determined to be dry during the first quarter 2008. <br />Approximately 4 feet of water was measured in this well during the second quarter 2008. <br />One full bailer of very clear water was removed from the well, and then the well went dry. <br />Similar conditions have been encountered in well MWOO1A in subsequent sampling events. <br />During the June 21, 2012, 1.9 feet of water was measured in the well, which is essentially <br />water filling the silt cap at the bottom of the well. It has been determined that water in this <br />well is sourced by formation condensation. The well is 100 feet deep. Samples were not <br />collected from well MWOO1A. <br />2 <br />