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2-523aa <br />2.7.5.3d Ground-Water Levels, I and J Pits, including the PR-11 Expansion Area <br />The ground water elevations in the area of the I and J Pits are depicted in the most current Annual <br />Hydrology Report (AHR). The water level elevation contours in the I and J Pits area are well defined in <br />the AHR. Future analysis of the area will define the changes in water level elevations and will be <br />included in Annual Hydrology Reports. <br />Historic monitoring wells GLUX, GE3 and 81-03A were completed in the First, Second and Third White <br />Sandstone aquifers, respectively, and demonstrated water elevations for the I and J Pit areas. More <br />recent monitoring wells CYA, CY1, CY2 and CY3 were completed in 2020 and monitor alluvium, First, <br />Second and Third White Sandstone aquifers, respectively. <br />Water levels in the I and J Pit backfill aquifers will decline due to the I and J Pit boxcut and subsequent <br />highwall mining (HWM). These drawdowns are expected to extend outward in the First, Second and <br />Third White sandstone aquifers for up to a mile in these relatively low permeability aquifers until water <br />levels recover in the backfill and HWM aquifer areas. The recovery of groundwater to a higher level <br />than baseline in the northern end of the HWM area will cause the levels in these three aquifers to <br />eventually be higher than baseline to the north of this mining. This will limit the drawdowns to the <br />north of the mining to several years with eventual recovery of water levels to above the baseline level. <br />Water levels in the boxcut areas will not recover to their pre-mine levels due to the increase in <br />transmitting ability in the HWM area.