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Ground Water • <br />Water Levels. Table 3 provides a summary of ground water monitoring <br />sites at the Yoast Mine. Water level data are provided in Appendix B. <br />Water level reports for the past six years are presented immediately <br />after the water level hydrograph of all data since 1991. Water level <br />measurements are collected with an electrical water level indicator or a <br />steel tape. Pressure readings (in psi) obtained from flowing wells with <br />pressure gages are multiplied by 2.31 to obtain head in feet. The <br />current ground water monitoring program is presented in Table 15-8 of <br />the Yoast Mine PAP. <br />- Alluvium. One well, YAAL14, monitors the Annand Draw alluvium. Two <br />wells, YGAL15 and 16, monitor the Grassy Creek alluvium. Eight wells; <br />YSAL1 to 6, 8 and 12; monitor the Sage Creek alluvium. Most well water <br />levels exhibit the typical seasonal fluctuation, increasing water levels <br />in the spring followed by decreasing water levels in the summer and <br />fall. Beaver dams may affect water levels in the alluvium. Most wells • <br />exhibited water levels this year within their historic ranges. Well <br />YSAL3 had the lowest water level on record in October 2005. <br />- Wadge Overburden. Four wells; YOV9, 28, 29 and 30; monitor the Wadge <br />overburden. Well YOV28 exists in the Annand Draw basin, all others exist <br />in the Sage Creek basin. Most wells exhibit typical seasonal <br />fluctuations, and water levels this year within their historic ranges, <br />although some lag time for the spring recharge is observed. We11 YOV28 <br />(downgradient of the 1996/99 mine pit in Annand Draw) has experienced a <br />decrease in water levels since August 1996, with the lowest on record <br />observed in October 2002. Water levels have increased since then. Well <br />YOV29 has experienced a decrease in water levels since October 1998 and <br />has been dry since May 2000. Well YOV30 has experienced a general <br />decline in water levels since it was first monitored in 1991. This year, <br />water levels are the lowest on record. Well YOV9 exhibited its lowest <br />water levels ever in October 2003, and has been dry since May 2004. <br /> <br />3 <br />