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~ Mayo and Associates, LC <br />have extremely limited or no communication with near surface hydrologic systems -both <br />surface and groundwater. In-mine groundwater tends to have carbon-14 (14C) ages of <br />thousands of years and, except in unusual circumstances which aze described below, is <br />' free of modem rechazge water as evidenced by the absence of tritium ('I~. Mayo and <br />' 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 near surface groundwater systems that are 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 are 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 />1 Evaluation of Potential Groundwater Inflows 18 Febmary 24, 2004 <br />Associated with E Seam Mining, <br />' West Elk Mine, Somerset, Colorado <br />