2011-02-25_REPORT - C1994082 - Laserfiche WebLink

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Ground Water 9 Water Levels. Table 3 provides a summary of ground water monitoring sites at the Yoast Mine. Water level data are provided in Appendix B. Water level reports for the past six years are presented immediately after the water level hydrograph of all data since 1991. Water level measurements are collected with an electrical water level indicator or a steel tape. Pressure readings (in psi) obtained from flowing wells with pressure gages are multiplied by 2.31 to obtain head in feet. The current ground water monitoring program is presented in Table 15-8 of the Yoast Mine PAP. Ground Water Level Summary. This year, water levels at all wells fell within their historic ranges, with the following exception. Wadge overburden well YOV30 has experienced a general decline in water levels since it was first monitored in 1991. Sage Creek alluvial well YSAL3 experienced its highest water level ever this year. An adjacent beaver dam in most likely the cause. All alluvial wells are showing distinct seasonal water level fluctuations in response to periods of precipitation recharge or the lack of precipitation. Overburden and coal well water levels are fluctuating in response to the precipitation recharge, induced ground water flow to the reclaimed mine pits. Ground Water Quality. Table 3 provides a summary of ground water monitoring sites at the Yoast Mine. Table 4a and 4b show the new (2010) ground water parameter lists. Appendix C provides all ground water quality data collected during the past two years, along with sampling remarks. This is followed by a plot of TDS versus time for the entire period of record. The regression line on this plot is generated by a method known as LOWESS (Locally Weighted Scatter plot Smoothing). Unless otherwise noted, smoothness factor (SF) of 1 (on a scale of 0 to 1) was used, which gives maximum smoothing. Finally, a statistical report representing baseline (i.e., premining) data for each well (when 3