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Require- <br /> <br />Requirement Require-ment <br />citation ment <br />complied <br />Comment <br /> with ? <br /> es / no <br /> DRMS previously concluded the Keenesburg Mine does not <br /> have the potential to negatively impact ground water and, <br /> therefore, a ground water point of compliance is not <br /> warranted (Memo to 2004 AHR file, dated 7/6/05). The <br /> memo of 7/6/05 also explains that if coal spoil or ash <br /> leachate migrated from the pit through eolian sand, Ennis <br /> alluvium, or the Laramie sandstone and coal, attenuation and <br /> dispersion would result in levels of TDS and SAR in ground <br /> water that are near pre-mining conditions within a few <br /> hundred feet of Keenesburg's pit. The mine monitors water <br /> quality in the Ennis alluvium and eolian sand in well DH-96, <br />R. Basic Standards CWQCC located approximately 6,000 ft. downgradient from the <br />for Ground regulations yes mine's pits. Multiplying conductivity by 73.6% to derive <br />Water 41.4 and 41.5 TDS, the concentration of TDS in well DH-96 averaged <br /> approximately 1271 mg/l in 2006 and 1242 mg/1 in 2007. <br /> (The 73.6% conversion factor is based on the observed <br /> relationship between field conductivity and lab samples from <br /> the DH-96 well.) The 2006 and 2007 TDS values are well <br /> below a 1750 mg/l background level identified in the 7/6/05 <br /> memo. <br /> Each pit disrupts the potentiometric surface. After final <br />S. Restoration of backfilling, the pits can be expected to show full recovery <br />ground water CDRMS of the potentiometric surface outside of the pits and water <br />recharge to regulation yes table (unconfined) conditions inside the pits. No <br />approximate 4.05.11(3) significant formation of surface spoil springs is expected <br />premining rate due to the flat topography; therefore, there will be no loss <br /> of ground water flows to surface waters. <br /> The Probable Hydrologic Consequences section of the <br /> permit application predicts no appreciable impacts to <br />T. Prevention of ground water systems outside the permit area. Water <br />adverse impacts CDRMS quality data from well DH-96 indicate there have been no <br />to ground water regulation yes adverse impacts to ground water in the Ennis alluvium and <br />systems outside 4.05.11 eolian sand outside the permit area, approximately 6,000 ft. <br />the permit area downgradient from the mine's pits. <br />U. Prevention of The approved post-mining land use of most of the permit <br />impacts to area is rangeland (a few acres are approved for <br />ground water CDRMS commercial/industrial gas well use). As previously <br />that adversely regulations discussed, ground water in the Ennis alluvium and eolian <br />impact the 4.05.1(2) and yes sand have not been adversely impacted by mining and <br />postmining land 4.05.11 reclamation operations at the Keenesburg Mine. Ground <br />use within the water in the Laramie coal and sandstone is not likely to have <br />permit area had adverse impacts as explained in the previous discussion <br /> of Basic Standards for Ground Water. <br />Page 3