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• 4) The overburden sandstone hydraulic conductivity <br />was assumed to be the same for all overburdens and <br />throughout the overburden at a value of 4.3 gpd/ft2 <br />derived from a 1979 aquifer test. <br />5) The area through which ground water inflow will <br />occur has a thickness represented by the thickness <br />of the coal seam plus the average thickness of the <br />sandstones in the overburden into which fracturing <br />due to mining will extend (page G-80). Fracturing <br />will occur when the mine is collapsed by pulling <br />the supporting pillars. <br />6) This assumption is part of the attempt to <br />maximize inflow conditions. Height of fracturing <br />due to mining will be twice the maximum predicted <br />• by Northern coal personnel in Section S (page <br />G-80). <br />7) The recharge area for the coals and the over- <br />burden is to the north in the area of the <br />topographic divide. <br />8) Ground water flows do not vary significantly <br />with season. <br />The maximum ground water inflows for each mine were <br />calculated as described on page G-81. Specifically, <br />the existing water Level gradient in each coal seam <br />was derived from the 1979 water level data <br />summarized here in Table A. The combined trans- <br />missivity of the coal and the fractured overburden <br />sandstones was derived as indicated in footnote (b) <br />• of Table B and in Table C. The existing water level <br />LeonaN Rice Consulting Water Engineers. Ix. <br />