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8. The TDS value observed on the lower Fish Creek site in July 2009 was higher than predicted in <br />the Probable Hydrologic Consequences (PHC) section of the permit application package. The <br />PHC predicted the maximum TDS value at Site 13 would be 607 mg/I, based on an increase <br />from 533 at Site 11 to 607 at Site 13 (increase of 13.9%). The value observed at Site 13 in July <br />2009 was 670 mg/I, while the July 2009 TDS value for Site 11 was 600 mg/I. This value <br />represents an increase of 11.7% from Site 11 to Site 13, which is within the predicted range. <br />The value at the upper site, prior to any mine related inflows, was elevated and the increase is <br />within the predicted range, so it does not appear that the higher TDS value observed at Site 13 <br />is an exception to the PHC. <br />Site June TDS mg/I <br />PHC/2009 % Increase <br />PHC/2009 July TDS mg/I <br />PHC/2009 % Increase <br />PHC/2009 <br />SW11 421/430 N/A 533/600 N/A <br />SW13 497/460 18.05%/6.98% 607/670 13.88%/11.67% <br />9. TDS values observed on lower Grassy Creek (SW-S2-2) were also above the maximum values <br />predicted in the PHC for both June and September. Again, elevated TDS was observed at the <br />upstream site (SW-S2-1) in both cases. SCC also notes that flow was considerably lower than <br />what was predicted at both sites. Again, given the elevated TDS upstream, it does not appear <br />that there are major departures from the PHC. <br />Site June TDS mg/I % Increase September TDS % Increase <br /> PHC/2009 PHC/2009 mg/I PHC/2009 <br /> PHC/2009 <br />S2-1 497/800 N/A 1233/2380 N/A <br />S2-2 554/910 11.47%/13.75% 2341/3730 89.9 <br />10. No NPDES effluent limits were exceeded in 2009. <br />11. Tables 13 and 15 of the AHR list the standards for Segments 13b and Be of the Yampa River. <br />SCC has derived a number of the standards based on the CDPHE Table Value Standards (TVS) <br />calculations using a hardness of 400 mg /I. The TVS formulas in the CDPHE regulations are <br />based on the hardness of the individual sample, so the standard for each parameter will vary <br />with each sample. A review of the 2009 hardness values for the Grassy Creek surface water <br />sites indicates that the simple average hardness value is 1,524 mg/I, with individual values <br />ranging from 186 mg/I to 2,790 mg/I; hardness average on the Fish Creek sites is 1399.5 mg/I <br />(ranging from 180 mg/I to 2,840 mg/1). CDPHE Regulation 31 states that "hardness values to <br />be used in equations... shall be no greater than 400 mg/1", but further states that "(f)or permit <br />effluent limit calculations, the hardness values used in calculating the appropriate metal <br />Page 3 of 5