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feet on non-toxic cover and topsoil. Analyses of D seam roof <br />and floor material contained in Volume 10 did not indicate <br />acid-forming, sodic, or otherwise inhibitory strata. <br />Pre-law surface mining activity in and adjacent to the <br />surface facilities area at Red Canyon resulted in a mixing of <br />geologic material, with piles of overburden left adjacent to <br />small mining and exploration pits. The operator filled in <br />the abandoned strip pits with underground development waste, <br />and covered portions of the waste with material from the <br />abandoned overburden piles. <br />b. Groundwater <br />For information regarding the groundwater system at the Red <br />Canyon Mine, refer to the Description of the Environment, <br />Hydrologic Balance section, previously discussed in this <br />document. <br />c. Surface Water <br />For information regarding the surface water system at the Red <br />Canyon Mine, refer to the Description of the Environment, <br />Hydrologic Balance section, previously discussed in this <br />document. <br />2. Probable Hydrologic Consequences <br />a. Groundwater Effects and Mitigation <br />Potential impacts to the groundwater regime have been <br />identified. During the active mining phase, mine pumping <br />could cause drawdowns in the coal aquifers, extending several <br />miles from the mine. Now that the mine is sealed, three <br />other impacts are likely to occur. Water in the flooded <br />workings is likely to acquire a greater salinity and a more <br />sodic character. This water may ultimately discharge to the <br />glacial-alluvial aquifer at the coal subcrops and result in <br />a degradation in water quality. Lastly, a spoil aquifer will <br />develop in the underground was to disposal area and the <br />backfilled areas of the reclaimed topography. <br />Total projected inflows to each of the two Red Canyon Mines <br />will average about 25 gpm. Actual inflows in the "E" Mine <br />averaged 25 gpm in 1983 and 1984. Distances downdip from the <br />mine from which drawdowns will be noticeable are predicted to <br />be 11.5 and 3.9 miles for the D and E seams, respectively. <br />The results of the modeling suggest that the drawdown will <br />not extend out to the glacial/alluvial aquifer through <br />unf ractured coals to the coal subcrops. Distances updip from <br />mine workings from which drawdowns will be noticeable are <br />predicted to be 44.6 Eeet and 5.8 feet for the D and E seams, <br />respectively. A buffer zone of 200 feet will be maintained <br />19 <br />