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:A~ • ~ • those observed when amount of drawdown is taken into account, Prediction of drawdowne which should occur from these eatimatee would be several tens of feet at one mile from the permit boundary. Drawdowns of approximately 60 feet occurred in the HI aquifer at well GB5 which is roughly one-half of a mile from Ashmore Pit. Observed dramdown has been much leas than expected, We, therefore, do not think drawdown eatimatee are warranted. Actual observation of drawdowna axe much more indicative of impacts. Also, the low permeability coal aquifers have limited drawdowns to the immediate vicinity of the active pits, Drawdowne downgradiene of the active mining areas recover much faster than expected. The increased permeability in she backfilled spoil aquifer transmits water to the downgradient end of the pit more readily. IM7ACTC Tn AD_i11DTGATF.D WR.LLS (See Man Mal) One First White Sandstone well, W-1406-78, exiate north of the Colt and Brown- ing Pite. This well 1a approximately 3700 feet north of the edge of Browning Pit (Appendix V, Part D). The First White Sandstone crape out north of the northern and of the Browning Pit. The southern limit of the First White Sand- stone is approximately 500 feet north of the northern end of Browning Pit (Appendix V, Part D), Impacts from mining would either have to be transmitted from the Second ox Third White Sandstone through shales to the First White Sandstone aquifer, or through direct contact of surface impacted waters with the First White Sandstone aquifer, It is unlikely that adequate vertical con- nection exiate between the Second or Third White Sandstone, and the First White 9andatone to result in negative impacts. However, there !e the poten- tial for surface water contact with the First White Sandstone and subsequent negative impacts to the aquifer. Therefore, during the second ar third quarter of 1988, a first white sandstone monitoring well, LVX-l, will be established to evaluate this aquifer in the Colt and Browning Pit area. Map M52 depicts the proposed location. The well construction will consist of 4-1/2 or 5•inch PVC pipe with the bottom 20 feet factory slotted. The well will be gravel packed to dust above the perfora- tions and sealed above the gravel aith bentonite pallets. The remainder of the annulus will be filled with wall cuttings with a 3-foot cement plug at the land surface. The sohadule of monitoring will be quarterly with the results included in the Annual Hydrologic Report (Appendix W), List B of Table 4,8- 12a will be taken in the quarter in which the well ie completed and Liet 6 of Table 4.8-12e quarterly thereafter for three quarters. Second White Sandstone well 8577.5A exiate west and north of the Colt and Browning Pits. Ths Second White Sandstone aquifer exiate only in the far northern portion of mining in this area. Mine drainage is estimated to be 100 and 13U gpm f8Y 1991 and 1991, Yeapectively, trom the pits in these areas. Only a small part of this drainage is expected to be produced from the Second White Sandstone because this aquifer will be thinly saturated in this area. 4-226e _'d REyiSED MpR 31 ~ 9fJINNIW-?J3ddtJtll LT:ST 86. TE 't1yW