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Mining related disturbance also eliminated the upper-confining shale layer of the overburden aquifers within the <br />area of disturbance. Elimination of this layer increased the potential recharge area for the overburden aquifers. <br />•The combination of increased permeability and increased recharge area is expected to increase the recharge rate in <br />the immediate area, a[ least initially. Since the recharge capacity of the backfill material will probably be liiglier <br />than [he undisturbed material, no diminution of groundwater flows is likely to occur as a result of mining and <br />reclamation operations. <br />Summan• of Probable Groundwater Hvdroloeic Consequences <br />The Eckman Park mining operations resulted in localized changes in the ion balance and chemistry of <br />groundwaters, increases in the concentrations of dissolved solids, localized changes in the potentiometric levels, <br />and minor increases in the recharge rate of the overburden aquifer. All of the potential groundwater impacts are <br />limited by existing climatic factors, the physical and hydrologic characteristics of the groundwater system, and [he <br />protection and mitigation measures practiced presently and during active mining operations. In addition, <br />potentiometric levels and recharge rates are expected to return [o approximately pre-mining levels within a few <br />years of final reclamation. <br />• Any groundwater impacts wlticlt have occurred will effectively be confined to the permit and adjacent areas by the <br />low transinissivity and limited lateral continuity of the groundwater aquifer, the limited amount of recharge <br />occurring in the area of disturbance, and the combined effects of dilution and dispersion within the groundwater <br />system. <br />Colorado Yampa/Twentymile Coal Company is the only water user with registered groundwater rights in the <br />permit and adjacent areas. The potential Hydrologic impacts will not adversely affect groundwater use in these <br />areas. Mining-related groundwater impacts outside of the permit and adjacent areas will not he significant and will <br />not adversely affect groundwater users in other portions of the groundwater basin. <br />• <br />1996 Permit Ren. Permit Renewal 780-144-23 Revised 3/18/97 <br />