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Hays Limestone and Smokey Hill Shale geologic units and any accumulated <br />water in the pit is from surface drainage, not from the highwall or the quarry <br />bottom. <br />Additionally, CEMEX's prior investigations have shown that water from C -Pit <br />did not migrate to a deeper monitoring well (CEM -005) in the Fort Hays <br />Limestone southeast of C -Pit, as shown by the lack of water in that monitoring <br />well. Brown and Caldwell concluded that the lack of water in this monitoring <br />well indicated that the fractures in the formation are closed off at a depth where <br />the formation dips to the southeast. Additionally, Brown and Caldwell reports <br />this unit is essentially a closed system in the area around C -Pit, as discussed <br />further in our response to Comment 4 and the attached discussion on site - specific <br />hydraulic conductivities (Brown and Caldwell). <br />Moreover, the Fort Hays and Smokey Hill units are in the Niobrara formation <br />which is primarily composed of marine limestone, chalk and chalky shale as <br />referenced to in Ground water Resources of the Bedrock Aquifers of the Denver <br />Basin Colorado (1976). Water in marine limestone can naturally be high in <br />chlorides, sodium and total dissolved solids. In fact, it is not uncommon for <br />ground water in some areas to have naturally occurring chemical constituents that <br />are greater than agricultural or drinking water standards (Plateau Environmental <br />services and CDS Environmental Services, 2001 and EPA website <br />http: / /water. epa. gov /drink/cont aminants /unregulated /sulfate. cfm). <br />To recap: <br />1. There is a significant amount of evidence that little to no water will <br />accumulate in the geologic units (Fort Hays Limestone) within the Niobrara <br />formation, Therefore, there is no relevant standard (e.g. drinking water or <br />agricultural use) for this formation. <br />2. Additionally, it is unlikely that CEMEX will be able to obtain background <br />samples to assess logical chemical constituent limits. <br />3. Without a background sample it will be difficult to create a standard for the <br />naturally occurring salts and selenium that reside in the bedrock within the <br />Forth Hays Formation. <br />4. CEMEX proposes the following reasonable standards. <br />Page 3 of 6 <br />