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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 azea (Figure SB, SE and SF) <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 azea 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/permit <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 eazlier 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 aze <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 azea 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 />perweabilities. Thus, these strata store and transmit very little water and aze not considered to <br />be aquifers. Therefore, the impacts 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 very slow rates of inflow resulting from dewatering strata <br />indicate that the quantity of water transmitted by these strata will not result in depletion <br />of ground water sources" (p. 10). <br />n <br />U <br />2.05-153 Revised November 1004 PRI G <br />