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1 <br />' hole in the floor was on the order of 1 gpm and was plugged by pumping an expanding <br />grout into the hole. This exploration hole is located about 1500 feet from 2-17L and the <br />leak in the floor may have reduced the piezometric pressure in the "lower sandstone facies" <br />at 2-17L. During March of 1987, another exploration hole (21012-10) was intercepted by <br />' mining in gate road 3rd East. This hole also leaked at about the same rate from roof and <br />floor. The hole in the roof was plugged with expanding foam grout. The hole in the floor <br />was plugged with Portland Cement pumped down a one inch line to about 100 feet. The <br />' leaks in both 21012-9 and 21012-10 are probably responsible for the fall in water levels <br />detected at 2-17L during the fourth water year. Mining of LW-1 approached to within 500 feet <br />' of this hole in February 1988. During this monitoring period, the water level ranged from <br />408.0 to 423.0 feet. Perhaps the combination of leaking exploration holes and floor cracking <br />as coal was removed by the longwall have reduced the piezometric pressure enough to drop <br />' the water level to this point. <br />Monitor hole 4-20L showed a drop of 10.9 feet in the water level. Well 32-7L showed a water <br />leveldrop of 4.1 feet while well 33-8L showed an increase of 1.0 foot. <br />' Monitoring hole 2-17L showed a drop of 3.9 feet. The response of "lower sandstone facies" <br />monitoring hole 2-17L to mining and leaking exploration holes indicates the area of influence <br />' in the "lower sandstone facies" is larger than that in either the "upper sandstone facies" or the <br />"siltstone-coal facies". <br />' From the baseline data, all three zones should be classified as "aquitards" in that they will <br />yield water but at very slow rates. Mining in the D Seam so far has encountered only small <br />' flows of water and the mine is essentially dry. Previously, water leaking out of caved areas <br />was routed to the sumps at the end of gateroads. From there it was pumped to the surface <br />through boreholes and discharged. The boreholes were designated as sump dewatering <br />holes (SDH2, SDH3, SDH5, and SDH6, see Plate 1). The dewatering hole SDH6 was never <br />drilled, and will not be drilled, because of the abandonment of the mining area due to the mine <br />' fire. The quantity and quality of this water is discussed in Section 2.2.2.5. No underground <br />water has been pumped out of these locations since the January 31, 1996 underground fire <br />episode. <br /> <br />1 <br /> <br /> <br />1 <br />