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State Req. <br />• <br />relevant in understanding the complex geohydrologic relationships which <br />exist throughout the permit down to the first aquifer below the lowest <br />coal seam to be mined. <br />I. Monitoring Network and Well Completion Information <br />• <br />4.05.13(a) Since 1977, Seneca Coals, Ltd. has drilled 46 ground water monitoring <br />wells in the permit and adjacent areas to assess the quantity and quality <br />of shallow aquifers. Many of these wells were drilled in cooperation with <br />the U.S.G.S, fo delineate the existing ground water regime in both dis- <br />turbed and undisturbed areas. Exhibit 7-2 shows the location of existing <br />observations wells in relation to the permit area and major structural <br />features (i.e., faults). A summary of water well data is listed in <br />Table 7-5 for the convenience of the reader. Appendix 7-I contains <br />additional information for each monitoring well, including date drilled, <br />borehole size, casing I.D,, perforated intervals, packing, seals, and <br />lithology. In addition, water levels are being measured monthly to deter- <br />mine the effects of surface mining on adjacent areas and to determine <br />the extent of mine spoil saturation in reclaimed lands. The water level <br />dots are presented in Appendix 7-2. <br />2. Aquifer Characteristics <br /> <br />As mentioned earlier, lithologic and structural relationships play an <br />important role in the development of aquifers at the Seneca II Mine. <br />Lenticular sandstones, shales, siltstones, and coal coupled with folding, <br />faulting, and abnormal thickening of coal due to the differential compac- <br />tion during deposition make the geohydrology of the Seneca II Mine <br />extremely complex. <br />In general, there are four basic water bearing lithotypes at the Seneca II <br />Mine. These consist of: (I) the discordant sandstones and shales which <br />make up the overburden and strata directly below the coal, (2) the fairly <br />uniform Wadge and Wolf Creek coal seams, (3) the nonindurated deposits <br />of spoil and alluvia! material and finally (4) the deeper continuous sand- <br />stone aquifers. Each of these systems can be further subdivided in <br />regard to their position on the stratigraphic column. Complete lithologic <br />7- 13 <br />Revised 5/27/81 <br />