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9 <br />i <br />C <br />I <br />42 <br />Figure 12 shows composition diagrams for samples taken from the Purga- <br />toire and the alluvial wells near the Maxwell Mine. The numbers in paren-. <br />theses are the total dissolved solids concentrations. Compiete data sets <br />are contained in Appendix E, Table E1. The composition of the water in the <br />alluvium is very similar to that in the stream, the only significant dif- <br />ference being a somewhat elevated sodium concentration in the alluvium re- <br />lative to that in the stream. Apparently, the elevated sodium concentration <br />in the alluvial waters is not caused by mining activities, because well <br />AL 3-3 is located upstream of surface activities (with the exception of the <br />access road) and of the point of mine discharge. The sodium is probably <br />being contributed by dissolution of one or more sodium salts contained in <br />the soils and alluvium. <br />Allen Mine <br />n <br />LJ <br />Similar computations were made to estimate the effect of the discharge <br />from the Allen Mine on the stream quality. The results are shown in Table 8. <br />Again, the indicated increases are believed to be conservatively large. <br />For these computations, a mean low flow in the stream of 3 cfs was used and <br />the mine discharge was taken as 73 gpm. The mean values of the parameters <br />measured at Stone~.vall as given in Table 5 were used for the upstream values. <br />TABLE 8 Effect Of Allen Mine Discharge On Stream <br />Quality At Law Flow ''.0 cfs) <br />Lhange In Concentration, mg/1 <br />PARAMETER Qm = 73 gpm <br />Total Diss. Solids + 32 <br />Alkalinity + l0 <br />Boron + 0.004 <br />Chloride + 0.25 <br />Iron (*.otal) - 0.02 <br />Fluoride + 0.06 <br />Sodi um + 14 <br />Bicarbonate + 25 <br />Zinc (total) + 0.002 <br />Also of concern is the effect on water quality in the Purgatoire of <br />the active waste dump at the Allen Mine. An analysis similar to that used <br />