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INTRODUCTION <br />Contour Consulting Engineering, LLC, (Contour) collected groundwater samples at the <br />GCC Rio Grande, Pueblo Cement Plant, on April 30, 2010. The samples were collected to <br />satisfy monitoring permit requirements, as stipulated by the Colorado Division of Mining <br />Reclamation and Safety (DRMS). Sampling, beginning in second half, 2008, has gone <br />from quarterly monitoring to semi-annual monitoring. The April 2010 sampling event was <br />the third semi-annual event, and the first for 2010. <br />WORK PERFORMED <br />Contour collected groundwater samples from three shallow alluvial monitoring wells <br />(MW002, MW003, and MW004) in the vicinity of the St. Charles River. The alluvial wells <br />represent downgradient conditions with respect to the Cement Plant operations. Deep well <br />MWOOIA is completed in the Codell Sandstone west of the plant. This well was <br />determined to be dry during the first quarter 2008. Approximately 4 feet of water was <br />measured in this well during the second quarter 2008. One full bailer of very clear water <br />was removed from the well, and then the well went dry. Similar conditions have been <br />encountered in well MWOOIA in subsequent sampling events. During the April 2010 <br />event, 1.1 feet of water was measured in the well, which is essentially water filling the silt <br />cap at 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 />MWO01A. <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 was <br />sounded during both 2009 sampling events, with similar results. Approximately 1 inch of <br />water was measured in well MW005 during the October 2009 and April 2010 events. This <br />water is also likely representative of condensation in the well. No sample was collected at <br />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 was 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 four measurement sets).