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4.8.2.2a. GROUND WATER INFLOW, 2008-2012. <br />DERRINGER PIT <br />The QR 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 2008 - 2012 term. <br />ASHMORE AND HAWKEN PITS <br />Average mine drainage from the Ashmore pit varied from 0 to approximately 20 gpm from 1997- <br />2001. Similar discharge rates are anticipated for the current permit term (2008 - 2012). Hawken pit <br />dewatering effectively ceased in 1997 with backfilling in this pit completed during the 1998 - 2002 <br />permit term. <br />FLINTLOCK PIT <br />Groundwater inflows to Flintlock pit including dewatering well volumes as well as pit pumping <br />volumes varied from 10 to approximately 30 gpm on average from 1997 to 2001. Dewatering well <br />• operations in F pit were discontinued in 1998. Comparable inflow rates are anticipated during the <br />2008 - 2012 permit term in F pit. Additional dewatering well installations are not anticipated but will <br />be installed if necessary. <br />GATTLING PIT <br />Mining of the H, I, K, L, M and Q seams is planned for G pit during the 2008 - 2012 permit term. <br />Aquifer dewatering wells utilized in G pit have produced from 2 to 29 GPM during the period from <br />2002 to 2007. Inflows attributable to groundwater are expected to continue at a similar rate during <br />the 2008 - 2012 permit term. The contour orientation of G pit may result in additional surface runoff <br />flows being retained in the pit. To the extent possible, diversion ditches will be utilized to route water <br />around open pit areas. <br />DRAW DOWNS <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 />• <br />4-226c <br />Revisions _ PP- -C (?