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Mayo and Associates, LC <br />~~ have extremely limited or no communication with neaz surface hydrologic systems -both <br />1 surface and groundwater. In-mine groundwater tends to have carbon-14 (14C) ages of <br />i thousands of yeazs and, except in unusual circumstances which are described below, is <br />free of modem rechazge water as evidenced by the absence of tritium (3IT). Mayo and <br />I Koontz (2000) and Mayo and others (2003) found groundwater encountered in Utah and <br />_ Colorado underground coal mines tend to occur as hydraulically isolated systems that <br />' often lack hydraulic communication within individual coal mines and coal seams. In <br />' contrast, they describe neaz surface groundwater systems that aze responsive to annual <br />' recharge and climatic variability and have young groundwater ages as active groundwater <br />flow systems. Springs that dischazge above and near West Elk Mine workings are parts <br />' of the active flow regime. <br />• Mine groundwater inflows aze lazgely associated with inactive groundwater flow <br />systems. In the coal mines inactive zone inflows typically occur as: <br />' 1) roof inflows from sandstone channels located in the lower portion of the <br />Mesaverde Group (i.e., lower Blackhawk Formation in Utah and Upper <br />and Lower Coal Members in the Somerset Coal Field). Inflows from <br />overlying sandstone channels issue from roof-bolt holes, vertical borings, <br />or channels which aze exposed during mining, <br />2) floor inflows from foreshore sandstones (i.e., Staz Point and Rollins <br />Sandstone) <br />3) damage zone inflows associated with faulting. These inflows significantly <br />~~ increase groundwater inflow rates and volumes from the Staz Point <br />Evaluation of Potential Groundwater Inflows 18 February Z4, 2004 <br />Associated with E Seam Mining, <br />West Elk Mine, Somerset, Colorado <br />