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• Magnesium Spring 1 magnesium concentrations were the lowest observed of the three springs and consistent over the last two water years. Spring 3 magnesium concentrations were elevated during the Srst two water years of the reporting period, decreased through water year 1999 and have been increasing slightly in the last five water years. This years concentrations are both below the 2003 water year recorded high of 256 mg/L. Spring 4 magnesium concentrations have flowed the same trend as Spring 3 with decreases from averages in the 165 mg/L range (water years 1995-1996) to an average in the 125 mg/L range during the 2000 and 2001 water years. In water years 2002 and 2003, concentrations were elevated (averaging 222 mg/L), while this water year the value was 194 mg/L. Concentrations of magnesium do appear related to flow condition with the higher concentrations occurring during low flow states. Manganese As with magnesium concentrations, manganese concentrations at the springs have shown different trends over the reporting period. Concentrations at Spring 3 have remained consistent and lower than Spring 4 during the reporting period, while concentrations at Spring 4 have significantly decreased by an order of magnitude during the same time (from 2.3 mg/L (WY1995) to below detection levels (WY2002 total concentration). This water yeaz, manganese concentrations were at or close to the lower detection limits for all . springs. Sodium Sodium concentrations at the springs have remained fairly variable over the last ten years, though overall concentrations have risen very slightly in both Springs 3 and 4. Spring 3 concentrations have remained in the 89-120 mg/L range. Second calendaz quarter values were slightly elevated above the average this water yeaz (135 mg/L). Spring 4 concentrations have generally fluctuated more than Spring 3, ranging from 96-140 mg/L during the period from water year 1995 to water yeaz 2002. The last two water years, concentrations have been in the 132-171 mg/L range, though the March 2004 level was lower and barely above the historic range. The sodium adsorption ratios for both springs reflect the same overall trend as sodium concentrations. Spring 1 concentrations are significantly lower for sodium, with a lower calculated SAR value. Sulfate As with several other constituents, sulfate concentrations at Springs 3 and 4 remained consistent from water year 1995 through water yeaz 2001. The prior two water years showed some elevation in concentrations in sulfate for both springs. The 1995-2001 ranges for Spring 3 were between 1440 and 2000 mg/L, while the last two water years . have revealed a range of between 1850 and 2300 mg/L. Spring 4 values have show a l.arDOn Junction Mine Page 7 Annual Hydrologic Report for Water Year 2006