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Observations on Edna Mine Annual Hydrology Report for 1996 <br />• Surface Water: over the last several years, the difference in TDS and <br />Individual dissolved components between sampling sites C and D on Trout <br />Creek has almost vanished. <br />This may coincide with switch in sampling points from old site D in <br />section 19, upstream more than a mile to new site C in sec. 26. <br />Springs (1+2), (3+4), (5+6+7), (12+13+14), and (16+17) were sampled for <br />full suite in May because of their high flow (>20 gpm). <br />Comparisons to PHC (Probabl~}Hydrologic Consequences) in permit: <br />* "predicted groundwater TDS to rise to 3000 mg/1" P. i"5-46 <br />is happening, but the higher concentrations are starting at TR-1.5 <br />(supposed to be upgradient station ... upstream of mining activity). <br />AHR attributes that to old underground mine upstream ... <br />so now we are adding water w/ similar dissolved solids contents from <br />spoils (represented by WR-1 well) to this high-TDS groundwater at TR- <br />1.5. Ignoring mixing details, this will probably produce higher TDS <br />contents as waters mix. This high TDS water will probably migrate down <br />to downstream stations TR-3 and 4 in next several years. Because of <br />this influx of high TDS water from upstre~ predictions for groundwater <br />• will probably be exceeded in the future. <br />t s,iol <br />* "predicted post-mining groundwater TDS of 2828 at West Ridge..." ~~ <br />This is exceeded as demonstrated by water from well WR-1; last four <br />years WR-1 water has ranged from 3000 to >4000 mg/1 TDS. <br />Spring 1 has reported TDS of 3200 while combined constituents total 4054 <br />mg/1 indicating that reported TDS value is low. A simple extrapolation <br />yields 25°s higher total of dissolved salts entering Trout Creek from <br />groundwater beneath West Ridge than predicted. ,,, <br />~~o <br />* "predicted post-mining groundwater TDS of 2290 at Moffat..." 2 ~ <br />Q <br />As above, if we add values for dissolved constituents from full-suite <br />analysis of water from springs (12+13+14) and (16+17), it looks as if <br />groundwater from Moffat exceeds predictions from PHC. <br />While reported value of TDS for springs (12+13+14) is 3800 mg/1, <br />individual measured constituents total >4500 mg/1 (18°s higher). <br />Reported TDS at springs (16+17) is 3500 while individual components <br />total >4700 mg/1 - is 34% higher. <br />Reported TDS for Moffat groundwater is -50% higher than predicted while <br />sum of analyzed values indicate contents are twice the predictions. <br />• <br />