Laserfiche WebLink
YAAL14. A prediction for Lower Grassy Creek alluvial well SGAL-70 was not made as part of <br /> the PHC. The average TDS concentrations measured from 2014 —2018 at alluvial wells are: <br /> Well TDS (mean) TDS (range) <br /> (mg/L) (mg/L) <br /> Sage Creek Alluvial Well: YSAL3 1077 910 - 1210 <br /> Grassy Creek Alluvial Well: YGAL16 1499 1180 - 1670 <br /> Armand Draw Alluvial Well: YAAL14 3001 2010—3510 <br /> Although the post mine TDS concentrations have exceeded the projected concentrations the post <br /> mine concentrations do not preclude the potential suitability of this water for livestock or <br /> agricultural use. However,well yields may not be sufficient to support this use at YGAL16 and <br /> YAAL14. As of 2008,the TDS concentrations at wells YSAL3 and YGAL16 appear to be <br /> stabilizing and concentrations at YAAL14 are declining. The TDS concentrations at POC wells <br /> SGAL-70 and YSAL3 remain well below the TDS standard established in Appendix 15-1 <br /> (TR39) and none of the water quality standards have been exceeded at these locations. <br /> Additional information about the TDS trends at Yoast Mine are provided in the 2018 Annual <br /> Hydrology Report. <br /> TDS concentrations were projected to increase by 62% in the Upper Grassy Creek to 1337 mg/L, <br /> by 230% in Sage Creek to 2118 mg/L, and by 314% in Armand Draw to 3938 mg/L.No change <br /> was projected for Lower Grassy Creek with TDS projected to remain 2177 mg/L. The Lower <br /> Grassy Creek concentration was based on the TDS measured at former Seneca Mine monitoring <br /> location SW-S2-2, located just upstream of Scotchmans Gulch. The TDS concentrations <br /> measured in these streams between 2014—2018 were: <br /> SL-7 - 45 <br />