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<br />4.8.2.2a. GROUND WATER INFLOW, 2023 - 2027. <br /> <br />DERRINGER PIT <br />The QR seams were mined out in Derringer pit during the 1998-2002 permit term. Average mine inflows <br />to Derringer pit, including the D pit well dewatering which continued into early 1998, varied from just <br />over 1 to approximately 50 gpm during the period from 1997 through 2001. Additional dewatering <br />needs in this pit are not anticipated during the 2023 – 2027 term. <br /> <br />ASHMORE AND HAWKEN PITS <br />Average mine drainage from the Ashmore pit varied from 0 to approximately 20 gpm from 1997-present. <br />Similar discharge rates are anticipated for the current permit term (2023 – 2027). Hawken pit <br />dewatering effectively ceased in 1997 with backfilling in this pit completed during the 1998 – 2002 <br />permit term. <br /> <br />FLINTLOCK PIT <br />Groundwater inflows to Flintlock 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. Flintlock Pit was completed and backfilled by the fall of 2012. With <br />the addition of the N Pit Mining Area, directly north of the historic F pit spoils, additional dewatering well <br />installations were placed in the north end spoils, directly south of the N Pit south end-wall area, to assist <br />in ground control for this pit. Well pumping volumes have been minimal and are expected to remain <br />such during the current permit term. <br /> <br />KIMBER AND LANCASTER PIT <br />Kimber Pit has been fully developed and no other mining activities will be conducted in this pit. Mining <br />of the H, I, K, L, M, Q and R seams is planned for Lancaster Pit during the 2023 – 2027 permit term. <br />Aquifer dewatering wells utilized in the backfilled G pit area have produced from 2 to 29 GPM during <br />the period from 2002 to present. Inflows attributable to groundwater are expected to continue at a <br />similar rate during the 2023 – 2027 permit term. To the extent possible, diversion ditches will be <br />utilized to route water around open pit areas. Lancaster pit will be of the down dip orientation and is <br />not expected to produce or retain any more water than prior pits of this design. <br /> <br />NIGHTHAWK PIT <br />Mining of the K, L, M and Q seams is planned for the N pit during the 2023 – 2027 permit term. Ground <br />water inflow is expected to be similar to historic Flintlock Pit volumes. <br /> <br />4-226d <br />