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Carol Pahlke <br />December 23, 1980 <br />Page 20 <br />Response: Although Exhibit 54 contains a Memor- <br />andum dated December 21, 1979 which uses the words <br />"impermeable boundary" to describe the fault in Bush <br />Draw, the materials presented at pages 779-28aa <br />through 779-38aa establish the fault to be a hin- <br />drance to groundwater flow, not an impermeable boun- <br />dary to flow, While it was not known during the <br />pump test, well DH-4 probably did not react to the <br />test because the well does not penetrate the coal <br />aquifer. Furthermore, there is no displacement of <br />the piezometric surface in the area of the faults, <br />as shown on Map 15a. Consequently, Kerr Coal does <br />not believe that the faults create "at least 2 <br />isolated ground water basins", and Kerr Coal main- <br />tains the accuracy of the description of the ground- <br />water system presented at pages 779-28aa through <br />779-38aa. <br />Revised Pages: Revised pages 779-28aa through 779- <br />38aa were previously submitted to MLRD and OSM as <br />part of the November 21, 1980 response of Kerr Coal <br />to the OSM Apparent Completeness Review. <br />Also, the open pits of the Kerr Mine are on the western limb of <br />the Johnny Moore Syncline. Dewatering this limb of the syn- <br />cline will lower the piezometric head on the eastern limb of <br />the syncline due to the "U"-Tube" effect. This will have two <br />effects on the ground water in the pit and the coal aquifer. <br />a. Dewatering the coal aquifer down to the pit level <br />during mining; <br />b. Accumulation of water in the pit after the pumps are <br />shut-off in the pit. <br />Please have Kerr comment on these concerns. <br />Response: The effects caused by dewatering, <br />including the "U"-Tube" effect, are described at <br />pages 780-112aa through 780-114aa. Dewatering of <br />the coal aquifer will cause a lowering of water <br />levels in the east limb of the syncline, but this <br />temporary drawdown will have no adverse effect. <br />Similarly, although accumulation of water in the <br />backfilled pit will occur, this accumulation will <br />have no adverse effects on the hydrologic balance. <br />