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Samples from Yell 7A2, faceted in the Xubberson Gulch alluvium downstream of mine <br />• diachsrges, display a CaMg'XC03504 type water with an average TDS vslue o} 1,116 mg/l in <br />1994. This is higher then the 1,047 mg/l baseline average, but falls within the baseline <br />range of 760 to 1,366 mg/l. <br />Samples from Yell 19A, bested in the alluvium of a 8ubberson Gulch tri butery (006 Gulch) <br />that contains mine discharges from the NPDES 006 pond, display a MgCaNe-504 type wster <br />with an average TDS value of 1,907 mg/l in 1996. This is lower than the 2,158 mg/L <br />baseline average, but fells within the baseline rsnge of 1,508 to 2,394 mg/l. <br />Monitoring of eight additional elluvlel wells ie required ae part of the monitoring <br />program established on October 4, 1991 (see preceding Alluvial Ground Veter Level <br />section). Sampling was started et these eight wells in the fall of 1990 (GY-S2Y series <br />wells, see Table 5, Appendix A), or in the spring of 1991 (USGS series wells). All date <br />collected prior to September 30, 1992 has been svereged together to provide baseline <br />information for the milliequi valent table (Table 5, Appendix A). In addition, ell 1993 <br />end 1994 data 1s also provided. Yell 20A (NPDES 005, Dry Lreek Basin) had no water to <br />sample since monitoring began. All USGS series wells are situated on Sage Creek upstream <br />• of mining, Nhile ell the new GY-52V aeries wells (except Yell 20A, see above) ere also on <br />Sage Creek end, as of yet, have not received mine discharge rater from VPDES 009. A <br />descriptive evaluation of the water chemistry of these seven wells Nill be provided when <br />NPDES 009 begins discharging. <br />Yedge Overburden. Samples from YeLI 140V, located in the north mining area where mining <br />began in November, 1992, display a MgCa-g04NC03 type wster with an average TDS value of <br />1,777 mg/l for 1994. This vslue is both lower than the bsseline sverege (3,513 mg/l) and <br />the baseline range of 3,464 to 3,562 mg/l. <br />• <br />Samples from Yell 150Y, also located in the north mining area, display a Me-S04 type water <br />with en average TDS value of 2,646 mg/l for 1994. This is lower than the baseline average <br />(3,394 mg/l) but falls within the baseline range (1,810 to 1,422 mg/l). <br />Yelt 160V is located st the north end of the south mining area in which mining began in <br />1990. Ac yet, no samples have been collected from this well due to low casing volumes <br />(two gallons or lees). <br />5 <br />