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<br />The Wolf Creek overburden and Wadge underburden are monitored by <br />wells GW-s7-WCO, 8P1-U, and 11-U. Well s7 again displays the CaMg- <br />S04 type water common throughout the permit area with highly <br />variable TDS values. The TDS levels have dropped since 1987 in <br />this low recovery well. SP1-U and 11-U both yield NaHCO3 type <br />water with TDS values consistently under 900 mg/1 and are rarely <br />both monitored concurrently as only 50 feet of lateral surface <br />distance separate the two wells. <br />The Wolf Creek coal seam, the lowest coal seam to be mined, has an <br />extremely low yield (< .5 gpm), and low water quality. This <br />potential aquifer does not meet accepted definitions of an aquifer. <br />Therefore it is not considered relevant and is no longer monitored <br />by Peabody. <br />Conclusion <br />Seneca II has impacted both water quality and quanitity since the <br />original permit was issued in 1981. Low level well conditions have <br />been previously addressed. In terms of water quality Peabody has <br />exceeded domestic, irrigation or stockwatering standards at several <br />locations and on several occasions for the following parameters: <br />Manganese, pH, fluoride, cadmium, mercury, salt load (TDS), and <br />sulfate. Boron, nitrate, iron, ammonia, and arsenic have also been <br />found in suspect concentrations on occasion. Nearly all wells <br />monitored by Peabody for water quality are disply a CaMg-So4 type <br />water with Na and HC03 as occasionaly major consituents. <br />Water quality at several wells in the southwestern portion of the <br />permit area has improved with the cessation of mining in that area. <br />Recent mining of the Wadge coal seam in the southeastern portion <br />has caused some degradation of water quality in that area. Mining <br />of the Wolf Creek coal seam in the northern portion has likewise <br />cause some degradation. y <br />Taken the isolated nature of local aquifers and low transmissivi'~y <br />and permeability of local strata, and the lack of any ground water <br />use in the area surrounding Peabody's Seneca II mine (Well GW-s5-TC <br />excepted), we may reasonably conclude that Peabody's mining <br />activities at the Seneca II mine have not posed and should not pose <br />any discernable threat to current or future ground water uses in <br />the region. <br />cc. Susan Morrison <br />enclosure <br />