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C~ <br />The predicted value for Well WOV17, 4295 mg/1, was predicated on a 5.5'f. <br />increase of the premining value of 9072 mg/1, which is an average of <br />seveiral overburden wells. However, Well WOV17 exhibited a premining TDS <br />ave rage value of 8043 mg/1, while the next highest TDS Wadge overburden <br />well (WOV15) had a baseline TDS average of ,3741 mg/1. Well WOV17 also <br />exhibited a~high degree of baseline TDS variability (min. = 6860, max. _ <br />85861 mg/1). The average TDS value this -year, :,8450 mg/1, was below. the <br />PHC (prediction using the average bas e,line~, value (8043 + 5.58 = 8465 <br />mg/1D-', and is also below a 5.58 increase- :of the maximum baseline; TDS <br />value 08586 + 5.58 = 9058 mg/1). Also,~~as~~.explained previously in the <br />,alluvium°sect`ion, calculated TDS values. ace o~fjten,preferable to. measured <br />TDS ;values. The calculated TDS average value this year was 7900 mg/1 ., <br />More data will be needed to evaluate the long-term TDS trend. <br />i <br />- Wadge Coal. Four wells monitor the Wadge .coal seam. Well WW19 <br />exhibits an-increasing TDS trend. Well. WW1!6 .di d; .not have enough water <br />in iit to sample this year. In past years it~'dspla yed an increasing TDS <br />i <br />trend.` Well WW17 exhibits anearly level TD$--trend.- Well WW4 exists in <br />the ~II-W South Expansion area. Monitoring fat this well was resumed in <br />July 1997 after being discontinued in June. 11965. This well, so far, has <br />not been impacted by mining. <br />i <br />The I Seneca II-W PHC predicts an annual average TDS value of 2630 mg/1 <br />forjWell WW19, while a value of 9950 mg/1 (4805 mg/1 calculated) was <br />i <br />observed this year. For Well WW17, a value of 3002 mg/1 was predicted, <br />while a value of 895 mg/1 was observed this year. <br />As noted in the previous paragraph, Well WW14 experienced this year a <br />TDS exceedence of the PHC prediction. This prediction was based on <br />several assumptions. 1) Baseline water quality values were an average <br />of all Wadge coal wells at Seneca II-W. 2) Aquifer characteristics were <br />an average of all Wadge coal wells at Seneca II-W. 3) The Wadge coal <br />seam was saturated for its entire thickness (11.8 feet). <br /> <br />~~t ' <br />.vi <br />-,in <br />. ~ ~` <br /> <br /> <br />x <br />