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Iron and pH values are similar for the two wells. Conductivity levels in the Okie Plaza Well are somewhat higher than <br />the levels in 9 Mine Well as would be expected since the Okie Plaza Well is deeper and further from the outcrop. <br />The declines in the piezometric levels in the Middle Sandstone observed in Figures 12 through 17, in Section 2.04 -7, <br />Hydrology Information, are apparently related to dewatering and subsidence associated with Mines 5 and 6. The <br />declines in the levels in Wells 81 -01 and 83 -01 between 1988 and 1990 appear to have leveled off since the middle of <br />1990. Water levels in these two wells and in Well TR -7A measured during 1991 are similar to the levels measured in <br />1983 and 1984. The slight recovery from 1984 through 1988 is apparently the result of a shift in the location of <br />mining to an area further up -dip. Water level fluctuations since 1983 are greater in Well 81 -01 as compared to Wells <br />TR -7A and 83 -01, as would be expected since this well is closer to the location of mine dewatering. <br />The water levels in Well 83 -02 show a different pattern. The water level decline of about 150 feet from 1987 to mid - <br />1989 in Well 83 -02 is determined to be related to mine dewatering as No. 5 Mine workings approached the location of <br />the well. The more abrupt 200 foot decline in water levels observed near the end of 1989 and beginning of 1990 is <br />thought to be a drawdown response due to subsidence, as its location is only a few hundred feet horizontally from as F <br />seam longwall panel, which was mined in a similar timeframe. <br />Wells TR -4 and 83 -03 are located at greater distance horizontally from the active operations for Mines 5 and 6. Water <br />levels in Well TR4 appear to be related to the fluctuations observed on all three of the down - gradient Middle <br />Sandstone wells, 81 -01, 83 -01, and 83 -02. The water level decline in TR4 prior to 1984, and the subsequent recovery <br />up to 1988, closely parallels the trends observed in wells 81 -01 and 83 -01. The decline during the first part of 1991 <br />also parallels the trend in these two wells. The rapid decline during the last part of 1989 and the first part of 1990, <br />however, appears to follow the trend observed in well 83 -02, although the magnitude of decline is considerably less. <br />Well 83 -03 is the Middle Sandstone monitoring well located furthest (more than 1.5 miles) from active underground <br />operations for Mines 5 and 6. The water levels in Well 83 -03 show a pattern that requires further explanation given <br />that potentiometric levels at the well are under flowing artesian conditions. The overall trend for this well from 1984 <br />through 1992 suggests a decline in potentiometric levels in this well of about 25 feet based on the linear regression <br />line shown on Figure 17, Section 2.04 -7, Hydrology Information. The occasional sharp decline followed by rapid <br />recovery which appear in the time plot are, however, likely the result of errors in obtaining an accurate measurement <br />of equilibrium artesian pressures within the well. The long -term decline could be a pressure response due to the <br />overall drop in piezometric levels in the Middle Sandstone in the vicinity of Mines 5 and 6. On the other hand, there <br />was no apparent relationship between the fluctuations observed in Well 83 -03 with the fluctuations observed in other <br />Middle Sandstone wells, due perhaps to possible pressure measurements fluctuations and the further distance to the <br />well. <br />Based upon the 1992 piezometric map (Map 13), the ground water gradient in the Middle Sandstone ranges from 120 <br />feet per mile to the southwest to 60 feet per mile to the southwest. The drop in piezometric levels in the Middle <br />Sandstone unit above the subsided longwall mine panels in the F and E coal seams has created a potentiometric <br />gradient to the south in the vicinity of the longwall panels. <br />The rock slope entries between the `B" and the "H" seams are not anticipated to significantly modify the probable <br />hydrologic consequences. The rock slopes will be approximately 1,650 feet long, starting in the `B" seam at an <br />elevation of 5,147 feet, and ending in the "H" seam at an elevation of 5,622 feet. The ramps will be mined at a 15 <br />percent grade. Geologic characteristics of the area are known from borehole 94 -08. The ramps penetrate a series of <br />coal seams (E, F, and H seams), shales and sandstones. Three sandstone strata separated by shales will be <br />encountered in the rock slopes at the following intervals (from the bottom of the rock slopes in the "E: seams): <br />• 254 —528 feet (sandstone 275 feet thick) <br />• 828 — 962 feet (sandstone 134 feet thick) <br />• 1,039 —1,180 feet (sandstone 141 feet thick) <br />These three sandstones form the Middle Sandstone, which in several other exploration boreholes is composed of only <br />TR14 -36 2.05 -41 Revised 03/20/14 <br />