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1 <br />t from roof and floor. The hole in the roof was plugged with expanding foam grout. The hole in the <br />floor 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 detected <br />at 2-17L during the fourth water year. Mining of LW-1 approached to within 500 feet of this hole <br />' in February 1988. During this monitoring period, the water level ranged from 405.2 to 406.0 feet. <br />Perhaps the combination of leaking exploration holes and floor cracking as coal was removed by <br />the longwall have reduced the piezomefric pressure enough to drop the water level to this point. <br />' Monitor holes 2-7L and TW2-7L are on the same location and apparently also responded to the <br />' two leaking exploration holes. Longwell panel 3 was mined past this location in April 1990 and <br />the water level had dropped below 300 feet. Longwell panel 4 was mined past this location in <br />August 1991. Well 2-7L has a dry blockage at 260 feet while TW2-7L has a dry blockage at 659 <br />feet. <br />During this monitoring period, water level in monitor hole 36-2L has increased about eight (8) feet <br />to a depth of 188 feet. Monitor hole 35-4L was found to have a dry obstruction at 438 feet. As <br />noted previously, the 35-4 location was mined through during this period. <br />' Monitor hole 4-20L showed a relatively static water level of 237.0 feet during this monitoring <br />period. <br />' The response of 'lower sandstone facies' monitoring holes 2-f7L, 2-7L and TW2-7L to mining <br />' and leaking exploration holes indicates the area of influence in the 'lower sandstone facies' is <br />larger than that in either the 'upper sandstone facies' or the 'siltstone-coal facies'. However, the <br />response of these monitoring holes to low flows of about 1 gpm in the leaking exploration holes <br />' further indicates the low water flow characteristics of the 'lower sandstone facies'. <br />' Frorn the baseline data, all three zones should be classified as 'aquitards' in that they will yield <br />water but at very slow rates. Mining in the D Seam so tar has encountered ony small flows of <br />water and the mine is essentially dry. Previously, water leaking out of caved azeas was routed <br />' to the sumps at the end of gateroads, From there it was pumped to the surface through boreholes <br />and discharged. The boreholes were designated as sump dewatering holes (SDH2, SDH3, SDHS, <br />etc., see Plate 1). The quantity and quality of this water is discussed in Section 2.2.2.5. No <br />' underground water has been pumped out of these logtions since the January 31, 1996 <br />underground fire episode. <br />' 2.2.2.4 Bedrock Water Quality Water sampling and analysis are no longer required from the <br />bedrock monitoring holes. However, prior to entering Federal leases C-8424 and C-8425, one <br />' water quality sample will be collected and analyzed from each of the monitoring holes in federal <br />' 10 <br />1 <br />