Laserfiche WebLink
• May, a new minimum value was recorded for dissolved calcium accompanied by a new maximum value <br />for SAR. <br />Sodium concentrations in well 008-79-6 continue to exceed levels prevalent at all other Mine 3 <br />monitoring locations perhaps as a result of cation exchange as ground water migrates to the greater <br />relative depths penetrated by this well. The aforementioned cation exchange phenomena was thought to <br />be evidenced by the increases in sodium, bicarbonate, and SAR during the 1993 reporting period. <br />In general, the total dissolved solids concentration in both wells continues to appear to have stabilized <br />within established ranges typical for each site. No anomalous values were encountered during 1997. <br />TDS concentrations in both wells remain within the normal range for the Wadge Overburden. The <br />1997 data does not indicate any significant changes in trace metals concentrations. <br />Alluvium <br />The alluvial aquifer within the mine area is monitored with two alluvial wells (008-AV-1 and 008-AV- <br />2) completed in the Foidel Creek alluvium approximately 1000 feet upgradient from the confluence of <br />Foidel and Middle Creeks (see Figure 2). Both wells are completed to the base of the alluvium, about <br />14 feet below the land surface. <br />Water Levels - A plot of historic water levels in the two Foidel Creek Alluvial wells and in Foidel <br />Creek as measured at site 304 is presented as Figure 8. The water levels in [he wells and stream show <br />the expected typical seasonal interrelationship of relatively rapid increases and declines associated with <br />spring runofT. This seasonal variation at these sites is more pronounced here than in other wells as <br />• expected because of the shallow depths involved and proximity to Foidel Creek. The longer term Vends <br />in water levels at these sites generally parallel the fluctuations observed in annual streamllows. Tables <br />4B and SB provide period of rewrd statistical summary Wormation for water levels at Wells 008-AV-1 <br />and 008-AV-2. Table 11B provides period of record statistical summary information for water levels at <br />surface water monitoring site 304. <br />Water quality -Water quality data for the Foidel Creek Alluvium wells is presented on Tables 4, 4A, 5, <br />and SA. Water quality data for Foidel Creek Site 304 monitored in association with the alluvial wells is <br />presented on Tables I l and I IA. Only water level information was recorded during 1997 for site 304. <br />Plots of historic field conductivities for both wells and dissolved solids for well 008-AV-2 are presented <br />as Figures 9, 10, and 11. Water quality constituent concentrations for all parameters monitored during <br />1996 were within the established ranges historically associated with each site. The total dissolved solids <br />concentration in the Foidel Creek alluvial aquifer as measured at well 008-AV-2 have appeared to be <br />steadily increasing since approximately 1988 (see Figure I1). Values recorded in 1997 indicate a <br />leveling off of that trend. Seasonal variations in field conductivity are evident in the alluvial wells. <br />This is likely associated with the flushing effect of the relatively low dissolved solids surface water <br />recharging the alluvial aquifer during spring nmoff. <br />The 1997 data does no[ indicate any significant changes in trace metals concentrations although iron <br />and manganese values remain variable. Manganese and iron concentrations documented during 1997 <br />maintained levels within the historical ranges established at this site. <br />Spoils <br />• Two wells in the backfilled area of Mine 3 (008-SP-4A and 008-SP-SA) were installed in 1985 to <br />monitor water levels and water quality in mine spoils (see Figure 2). One well, 008-SP-4A, remained <br />