2012-11-27_REPORT - C1994082 - Laserfiche WebLink

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At Sage Creek alluvial well YSAL1, the TDS value observed this year was 920 mg /1. The TDS value observed this year upstream at Well YSAL3 (directly below Pond 012) was 1440 mg /l. These two values exceed the predicted value of 798 mg /1. The GWPOC well for the Sage Creek Alluvium, YSAL3, did not exceed the TDS GWPOC standard, 2675 mg /1. TDS values at YSAL1 are displaying a decreasing trend. This years TDS value at Wadge coal well YW30 was 7270 mg /1. The PAC predicted value for this well is 2570 mg /l. TDS values have been on the rise at this well since 2008. However, in 2012, the TDS value was 5680 mg /l, possibly indicating a downward trend. More data from this well will be needed to determine if the recent trend is an anomaly. Surface Water A summary of surface water sites is provided in Table 9. Stream monitoring occurs on Sage Creek at Sites YSSF3 and YSS2, and on Grassy Creek at Sites YSGF5 and YSG5. These surface water sites are monitored biannually for flow and, field parameters (pH, temperature, and electrical conductivity [EC]). NPDES Discharge Points 013 and 014 were monitored weekly for flow and pH until a new NPDES permit went into effect on July 1, 2010. They are now monitored monthly. All five NPDES sites are monitored monthly for NPDES parameters and field parameters. Samples obtained at the stream sites are analyzed for one of the new surface water parameter lists during spring runoff and summer baseflow. Spring sites are monitored in the spring season. The current surface water and spring monitoring program is presented in Table 15 -9 of the Yoast Mine PAP. All surface water data collected during this reporting period are provided in Appendix D. Data for each site begins with a flow hydrograph of all historic data (plus an annual hydrograph for NPDES sites), followed by a listing of individual water quality and quantity data for the current water year, and followed by remarks if present. This is 7