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Water-Treatment Plan For Ponded Water in C-Pit REC~~~~~ <br />CEMEX Lyons Plant DEC 0 11004 <br />Lyons, Colorado <br />Division of Minerals and Geolo®y <br />1 Introduction <br />Water accumulated in the C-Pit has contacted the disposed cement kiln dust (CKD) and <br />contains elevated concentrations of some of the regulated constituents, total dissolved <br />solids (TDS), selenium, chloride, sulfate, and pH, specified in the mining permit and a <br />recent inspection report. A recent report (URS, 2004) evaluated the potential impact of <br />ponded C-Pit water on groundwater quality in the Dakota Group sandstones beneath the <br />pit to determine the need for accelerated removal or treatment of the pit water to protect <br />groundwater quality in the Dakota sandstone. The evaluation concluded that the C-Pit <br />water did not pose a threat to groundwater quality in the Dakota sandstone. However, the <br />water may pose a slight risk to local wildlife who may infrequently visit the pit. To <br />alleviate this potential risk, CEMEX has agreed to remove and/or treat the water in C-Pit. <br />This report provides a water treatment plan if CEMEX is not successful in reducing the <br />present volume of water or constituent concentrations in C-Pit by December 1, 2005. <br />CEMEX is presently using the ponded water in the C-Pit to support plant kiln operations. <br />At the present use rate of approximately 70 gallons per minute (gpm), CEMEX estimates <br />that the approximately 35 million gallons of ponded C-Pit water will be reduced to as <br />small a volume as practical in about 12 months or by December 2005. The remaining <br />water in the C-Pit, which is assumed to be about 325,000 gallons, may also be used to <br />support plant operations if the current pump configuration in the C-Pit pond is modified <br />so that the remaining water can be removed. <br />In the event that CEMEX is not able to use all of the water ponded in the C-Pit, a <br />contingent water treatment plan is provided in this document to treat the ponded C-Pit <br />water. Two contingent water treatment options are provided. Option 1 involves <br />treatment of the existing quantity of ponded water, approximately 35 million gallons. <br />Option 2 involves treatment of the residual water that may remain afrer pumping is <br />completed in December 2005 to reduce the pond to it smallest practical volume. <br />Preliminary conceptual approaches and costs are provided for each treatment option. <br />CEMEX Water Treatment Plan ~ Revision 0 <br />