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Alluvial water quality monitoring in the Little Grassy Creek alluvium indicates that there have been slight increases in TDS, Ca, Na, and 504 at Wells Ch'-56-A and 32. At these points, the mean TDS levels are approximately 2,400 to 2,700 mg/7. Salt concentration as a result of evapotranspiration probably accounts for a large percentage of this. However, alluvial aquifer monitoring further downstream at the confluence with Grassy Creek (Well Gh'-533) suggests that the higher mean surface and around water flows have considerably diluted the system and a mean TD$ level of 1,030 mg/i was recorded in 1966. In the Wadge and Wolf Creek overburden wells, there have been no increases in TDS outside the ranges defined at these wells between 1980 and 1985, excepting We 11 GW-S36-0. This well is completed in the Wolf Creek overburden and was mined through in 1986. Prior to being mined through, there was a 10-fold increase in TD$ to approximately 3,750 mg/l. This increase, which occurred in a fairly short time period, was probably a direct response of the proximity of the active pit to the well. Blasting in such close proximity would open fractures (secondary permeability) in the adjacent, consolidated overburden which would provide avenues for the hieher TDS pit and spoils water to enter along. This TDS level is well within the ranges of TDS measured in spoils wells at Seneca II. Onl t o of th Wolf C k d h' o l d i i ll i h h i TDS y w ree an e a ge c a mon ng we tor s ave s ncreases own n during 1986 and these increase s have been very minimal. The Wolf Creek coat hell GW-536-WC is located immediately adjacent to Well GW-536-0 ref erenced above. The increase in TDS is also probably attributable to the proximate effects of mining prior to it being mined through. Wadge coal Well GW-S17 increased slightly in TD$ during 1966. It is located downdip from the Wadge impoundment and appears to be lareety controlled by the Wadge impoundment water chemistry. Well GW-S17 showed an average TDS level of 2,E93 mg/1 between November, 1985 and May, 1966. The Wadge impoundment ranged from 2,200 to 2,930 m9/1 during this same time period. Some higher TDS spoil ground water is also contributing recharge to the W'a dge coal aquifer. Of the three spoils wells monitoretl during 1986, only GW-526 showed a slieht increase ir. TDS. Chemical parameters contributin g to this in and Ca. Well GW-526 crease were 50 is 4 located upgra dient from GW-S 25 and downgra dient from GW-527. Its TCS levels are al so intermediate between those of the two other wells. Yell GW-525 r:i th the lowest TDS levels appears to be largely controlled by Wadge impoundment water chemistry. Well GW'-526 is located along the transition zone between 2-4 15-16 feet feet of saturation and of • ~ . h l f saturation in the spoils. Its water chemistry is er leve s largely influenced by hig o 30