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<br />All the monitoring wells showed some fluctuation in ionic concentrations this water yeaz. <br />The fluctuations were not consistent as far as the constituents that fluctuated or the wells <br />that showed fluctuations. The majority of the fluctuations were within historic ranges <br />observed for the wells over the last eight water yeazs. Notable changes are further <br />described below. <br />Ammonia <br />Ammonia concentrations for wells 17-B and 94-1 remained within historic ranges during <br />the 2002 water yeaz. Well 95-1 exhibited a significant rise in ammonia concentrations <br />during the 2000 water yeaz from 1.50 mg/L in the second calendar quarter of 2000 to 8.3 <br />mglL during the first calendaz quarter of 2001. The ammonia concentrations this water <br />yeaz for well 95-1 returned to lower levels, only slightly elevated from historic conditions. <br />Bicarbonate <br />Bicazbonate concentrations at the three wells remain within the historic ranges for each <br />well. Well 17-B exhibited an initial rise, followed by a drop in concentrations this water <br />yeaz that is also found in water yeazs 1995 and 1997 during the first calendaz quarter of <br />the water year. Well 94-1 showed an increase in concentrations during the period from <br />water year 1997 through water yeaz 2000, but that trend reversed during water yeaz 2001 <br />within levels remaining consistent with the water yeaz 2001 levels this yeaz. Bicazbonate <br />concentrations at well 95-1 decreased over the same period and aze increasing slowly at <br />this time. This may be indicative of a slowly moving concentration of bicarbonate ions <br />downgradient through the mine over the past several yeazs, however, the concentrations <br />through the azea have not exceeded historic ranges. <br />Calcium <br />Calcium concentrations remain consistent within well 17-B through this water yeaz. Well <br />94-1 exhibits historically wide fluctuations in calcium concentrations ranging from 23.9 <br />mg/L (fourth quarter W.Y. 1997) to 160.0 mg/L (first quarter W.Y. 1997). <br />Concentrations aze chazacteristically high during fall and winter attenuating during the <br />spring and summer months. Well 95-1 showed wide fluctuations in calcium <br />concentrations during water yeazs 1997 and 1998, but since then concentrations have <br />become very consistent. <br />Chloride <br />Chloride concentrations were elevated in wells 17-B and 95-1 during the past two water <br />yeazs (1999 and 2000). The last two water years chloride concentrations decreased in <br />both wells, though concentrations in well 95-1 remain at levels fifty percent above 1997- <br />19981eve]s. Chloride concentrations in well 94-1 remain low, near detectable limits. <br />Carbon JuncUan Mine Page 9 <br />Annual I{ydrologlc ReportPor Water Year 2002 <br />