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• 4.8.2.2a. GROUND WATER INFLOW, 2003-2007. <br />DERRINGER PIT <br />The OR seams were mined out in Derringer pit during the 1998-2002 permit term. Average mine <br />inflows to Derringer pit, including the D pit well dewatering which continued into early 1998, varied <br />from just over 1 to approximately 50 gpm during the period from 1997 through 2001. Additional <br />dewatering needs in this pit are not anticipated during the 2003 - 2007 term. <br />ASHMORE AND HAWKiEN PITS <br />Average mine drainage from the Ashmore pit varied from 0 to approximately 20 gpm from 1997-2001. <br />Similar discharge rates are anticipated for the current permit term (2003 - 2007). Hawken pit <br />dewatering effectively a:ased in 1997 with backfilling in this pit completed during the 1998 - 2002 <br />permit term. <br />FLINTLOCK PIT <br />Groundwater inflows to F=lintlock pit including dewatering well volumes as well as pit pumping volumes <br />varied from 10 to approximately 30 gpm on average from 1997 to 2001. Dewatering well operations in <br />• F pit were discontinued in 1998. Comparable inflow rates are anticipated during the 2003 - 2007 <br />permit term in F pit. Additional dewatering well installations are not anticipated but will be installed if <br />necessary. <br />GATTLING PIT <br />Mining of the L, M and O seams is planned for G pit during the 2003 - 2007 permit term. Aquifer <br />dewatering wells utilized in G pit have produced only minimal amounts of water in this area. Inflows <br />attributable to groundwater are expected to continue to be minimal and comparable to those inflows <br />encountered in F pit. The strikeline orientation of G pit may result in additional surface runoff flows <br />being retained in the pit. To the extent possible, diversion ditches will be utilized to route water around <br />open pit areas. <br />DRAWDOWNS <br />Prediction of drawdown, which should occur based on the above estimates, would be several tens of <br />feet at one mile from the permit boundary. Observed drawdowns have been less than these <br />predictions. Actual observations of drawdowns are much more indicative of impacts. These low <br />ii <br />4-226c <br />Aped o",: ;:(f71~ <br />