Laserfiche WebLink
Hole 31 -7M decreased in water level 0.1 feet. This well is up gradient from mining <br />activity and the water level fluctuation is minimal. <br />Monitoring Hole 32 -7M was plugged in August 2010 to eliminate connection with the <br />sealed off portion of the mine. <br />33 -8M experienced a slight rise in water level of 1.3 feet, within the normally expected <br />range of fluctuation. <br />The hydrographs of the 'lower sandstone facies" are designated by the letter "L" following <br />the hole number. <br />Hole 2 -17L showed a rise of 24.6 feet from the prior year. This rise is attributed to the rise <br />in water level within the D -seam workings. <br />Hole 4 -20L showed a drop of 1.3 feet from the prior year. <br />Hole 33 -81- showed a 0.4 foot rise in the depth to water. This response is similar to the <br />adjacent 33 -8M hole. <br />Monitoring hole 22 -21- was completed in October 2005 for monitoring future mining <br />expansion. This hole recorded a 53.4 foot drop in the water table over the prior year. <br />This apparent fluctuation is difficult to explain since the nearest longwall mining is over <br />one mile away and no other subsurface activity occurred recently in its vicinity. Other <br />abrupt changes in water level were observed at this well shortly following its construction <br />(see Appendix D -14). These fluctuations are most likely naturally occurring due to unique <br />but unexplained hydrogeologic characteristics unrelated to mining activity. <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 B Seam so far has encountered only <br />small flows of water and the mine is essentially dry. Typical inflows are in the order of 20 <br />to 40 gpm (includes water resulting from leaks, water line brakes, and other similar <br />contributions as well as that originating from inflows from geologic formations) with <br />occasional short term increases when localized perched water tables are encountered. <br />The average amount pumped from underground during the water year was 25.46 gallons <br />per minute. <br />Water leaking out of caved areas is routed to the sumps at the end of gateroads. A new <br />dewatering system was installed in May 2012 to pump excess water captured <br />underground to the surface for treatment, re- infiltration, and potentially discharge. Prior to <br />