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Water levels in Wadge Overburden aquifer wells 009-79-4 (Figure 9), located upgradient <br />from the mine, and 006-82-74C (Figure 10), located near the portal area, have been <br />measured since 1982. The data indicates a relatively stable water level in the two wells <br />since underground mining began. The data from the 009-79-4 well shows a strong <br />seasonal variation in the Wadge Overburden water levels. Water levels are highest in the <br />spring following snowmelt recharge, and decline through the year to the lowest levels in <br />the winter. No such trend is appazent in the Twentymile Sandstone or Trout Creek <br />monitoring well data. <br />The water level in Wadge Overburden wells 006-87-1 and 006-88-2 indicated significant <br />impact from the neazby underground mining prior to their replacement. The data for <br />well 006-87-1 indicated that in 1988 the water level declined more than 400 feet and <br />dropped below a restriction in the well beyond which measurements could not be taken. <br />It appeazs that the water level decline in this well is a result of mine inflows from the <br />Wadge Overburden in this area. Since 1990, further caving or collapse of the well casing <br />has occurred, resulting in a maximum penetration of the water level measurement probe <br />of 349 feet. The recorded data since the water level drop in 1988 reflects the deepest <br />penetration of the water level probe, not an actual water level reading. The water level <br />in We11006-88-2 has declined almost 400 feet between fall 1988 and fall 1990 as a result <br />of mine-related dewatering of the Wadge Overburden. Measurements of water level <br />could not be taken in 1991 due to a collapsed casing at a depth of 200 feet. This well <br />has been sealed and abandoned. <br />1• We1191-M006 replaced we1106-87-1 in fall 1991, while well FBR-1la replaced well 06- <br />88-2. Well 91-M006 shows a decline in water levels since completion which is most <br />likely related to localized de-watering of the Wadge overburden by mining activities. <br />Well FBR-11A reflects the typical seasonal trend of Wadge overburden wells, and has <br />not shown any impacts related to mining (Figures 11 and 12). <br />Water Quality <br />The water quality data for the three Trout Creek sandstone wells do not indicate any <br />water quality impacts from underground mining at Foidel Creek. The water quality data <br />for the Trout Creek Sandstone aze summarized on Tables 4, 5, and 6. A plot of field <br />conductivity is presented in Figure 13. The data for we11006-83-48C may indicate that <br />the water quality has been effected by migration of fluids from the cemented zone of the <br />well into the open azea of the well. This well was scheduled for replacement by well <br />FCMN2 during the 1993 water year, but the replacement well was not installed until <br />October 1993, since which time problems with completion of the well have been <br />encountered. Western American Drilling tried to access the site during May, 1994, but <br />ground conditions were not favorable and the grouting project was rescheduled until June, <br />1994. Both Western American and I-Ialliburton well be used to high pressure grout the <br />-3- 6/10/94 1:23 pm <br />