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Ground Water Summary <br />TDS trends are decreasing at two wells, stable at four wells, and <br />increasing at eight wells. CDOH agricultural ground water standards for <br />pH, fluoride, iron and manganese were exceeded at certain monitoring <br />wells. In the area surrounding Yoast, ground water is not being pumped <br />for irrigation or livestock watering purposes, nor has the CDOH <br />classified any aquifer in this region for any use. The above discussion <br />is provided only to serve as a comparative basis to judge ground water <br />quality. <br />In the Probable Hydrological Consequences (PHC, Tab 17, Attachment 17-5) <br />section of the Yoast Mine PAP, predictions were made as to the expected <br />TDS increases to be observed at various monitoring wells. The following <br />table outlines these predictions along with this year's observed average <br />values (annual average for bedrock wells, May-September average for <br />alluvial wells). <br /> <br />Well Predicted TDS values (mg/1) This years average TDS (mg/1) <br />YOV28 2587 1190 <br />YOV29 3201 Dry <br />YOV30 3201 1130 <br />YW28 3045 920 <br />YW29 2570 460 <br />YW30 2570 1010 <br />YWU29 2670 420 <br />YWU30 2670 1120 <br />YWC33 2721 830 <br />YAAL14 2036 2770 <br />YGAL15 3548 5450 <br />YGAL16 1296 1030 <br />YSAL1 798 1310 <br />The TDS value in May at Well YSAL1 was 1310 mg/1, which exceeds the <br />predicted value of 798 mg/1 by 64~. The PHC predictions are based on • <br />long-term average values. Individual TDS measurements will vary from <br />8 <br />