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West Elk Mine <br />• 5. "Preliminary aquifer tests performed by Mountain Coal Company indicate that the F Seam and <br />lenticular sandstones of the Barren Member are poor aquifers at best, as groundwater flow is <br />mainly concentrated in fractured rock." <br />MCC's stratigraphic cross-sections from boreholes in the permit area (Figure 5B, 5E and 5F) <br />confirm the lenticular nature of the sandstone units and the lack of groundwater. Again, <br />"aquifer" is a term which should not be used in this context. <br />6. "Occurrences from ground water have been noted in the Mesaverde Formation from <br />information obtained from drilling, experiences in the mine, and from the presence of springs <br />and seeps in the region. This information also indicates that the only potential (emphasis <br />added) regional bedrock aquifer in the general area is the laterally continuous Rollins Sandstone. <br />The laterally discontinuous lenticular sandstones within the Upper Mesaverde Formation <br />support only localized groundwater flows, and are considered to be insignificant in terms of the <br />overall hydrologic balance." (p. 5). <br />WWE emphasizes that this statement appears in nearly all of the documents/reports/pem-it <br />language from West Elk Mine, and is consistent with the long-term understanding of Mr. <br />Dunrud. The only potential the Rollins Sandstone has as an aquifer is that it is a laterally <br />continuous sandstone unit, and as such, would be thought to contain water, but due to the <br />depositional immaturity of the Rollins Sandstone, it actually acts as a water barrier. <br />Furthermore, the Rollins Sandstone is not an aquifer at or in the vicinity of the mine, as <br />. discussed earlier in Section 2.05.6. <br />7. "Should water from different sources mix as. a result of subsidence fracturing, modifications in <br />groundwater chemistry could be observed. No significant changes in water chemistry are <br />predicted, however, due to the small volumes of groundwater present in the Mesaverde <br />Formation and the similarity in chemistry of individual aquifers." (p. 10). <br />WWE has evaluated probable water quality changes in some detail and has reached the same <br />conclusion. The groundwater quality data collected by MCC since 1996, continue to support <br />this statement. <br />8. "Water often enters the mine in a newly mined area by de -watering the coal seam, adjacent roof <br />or floor. These sources of mine inflow usually dry up within one to two weeks. The minor <br />amount of water resulting from dewatering of the coal, roof, and floor indicates that the <br />coals and the overlying and underlying strata in the Mesaverde Formation have very low <br />permeabilities. Thus, these strata store and transmit very little water and are not considered to <br />be aquifers. Therefore, the irnpacts of de -watering the coals and the strata immediately above <br />and below the coals within the Mesaverde Formation should have an insignificant impact on the <br />hydrologic balance. Also, the venF slow rates of inflow resulting from dewatering strata <br />indicate that the quaantit-e� a e,vater` transmitted by these sti-ata will riot result hi depletion <br />of groundwater sources" (p. 1 J). <br />2.05-182 RevisedJune 2005 PRIO. Jam+arn 2006. Alarch 2006: Rev. May 2006 PRIG, Alov. 2006 TRI07;Sep. 2007 PR12;Feb 2008 PR12 <br />