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the greater abundance of "bomb" water in the sump and seep relative to the fault implies that the <br />faults contain a higher abundance of non-bomb, i.e. old, water. Nonetheless, the presence of any <br />"bomb" water in the faults implies either a relatively young age or a mixture of old and young <br />waters. This supports the notion, presented above under the oxygen isotope discussion, that <br />groundwater recharge may be relatively rapid, in this case, possibly less than 50 years. <br />SUMMARY <br />Overall, the geochemical information supports an interpretation that waters from the faults <br />in the West Elk mine combined with meteoric water which had acquired dissolved constituents <br />en route to the Northwest panels sump, and this water is now leaking across the B-seam dam <br />between the Bear Mine and West Elk Mine and out the Edwards Portal seep. <br />Dilution of the fault water with impure meteoric water can explain trends in major element <br />composition that goes from a sodium bicarbonate water to a dilute, mixed sodium calcium <br />magnesium, sulfate water. The occurrence of sump water on a trajectory between the fault <br />waters and the seep water augment this interpretation. <br />Shifts in carbon, oxygen, and hydrogen isotope compositions also can be explained through <br />simple dilution with local impure meteoric waters. Variations in S"C between the faults and the <br />seep, and between the sump and the seep, do not provide a compelling argument in favor of a <br />third water source; the same changes can be explained with other simple reactions, of natural <br />variability uncertainties. <br />Younger carbon-14 and tritium ages in the sump and seep can be ascribed to the presence of <br />more modem waters in these areas than the faults. Local meteoric waters would be modem <br />waters. <br />Sulfur isotope shifts require incorporation of sulfate which was probably derived from a <br />source azea undergoing sulfate reduction. Such shifts aze compatible with methane oxidation, <br />which could explain the shift in S"C values as well. <br />Gas compositions support the notion that modem water may be a component of some of the <br />fault waters. Coupled with the fact that the oxygen and hydrogen isotopes fall close to the <br />meteoric water line, and the evidence that there has been only relatively minimal oxygen isotope <br />exchange between the waters and rock oxygen in even the hottest fault samples, argues for <br />somewhat rapid meteoric water recharge of the fault waters. <br />The constant temperature of the seep indicates that, provided the sump water is the source of <br />the seep water, the sump is being constantly replenished with hot fault waters. If the fault waters <br />cease being discharged to the sump, or if they are stored elsewhere, the seep waters, if derived <br />from the sump, should cool. Otherwise, this would argue for a separate source. <br />There is evidence that the sump waters which were sampled may not be representative of <br />that in the entire sump, and so may differ from that which could be seeping across the B-seam <br />dam. A tracer study could clazify this question, decisively. <br />Missing and confiising data notwithstanding, there appears to be ample geochemical support for <br />the interpretation that the fault waters, once discharged to the Northwest Panels sump, are <br />combining with meteoric water and leaking across the B-seam barrier and out the seep. <br />10 <br />