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Particle-size distributions were also determined for the Seneca II-W South overburden core <br />samples. The percentage of sand, silt, and clay-size particles comprising the core volume are <br />presented in Table 17-35, Summary of Particle Size Distributions of Seneca II-W and Seneca II-W <br />South Core Samples. Available data indicate that Wadge overburden in both areas is comprised <br />of predominantly silt- and clay-size particles. Silt percentages in the Seneca II-W area vary from <br />34.5 to 55.0 percent; clay percentages vary from 21.0 to 51.0 percent. Silt percentages in the <br />Seneca II-W South area Wadge samples vary from 42.0 to 47.6 percent; clay percentages vary <br />from 14.6 to 39.5 percent. The Sage CreeklWolf Creek overburden particle-size data collected <br />from the nested well locale indicates that these units are comprised primarily of silt- and sand- <br />size particles. Silt percentages in the Sage Creek/Wolf Creek area range between 33.3 to 40 <br />percent; sand percentages vary from 44.5 to 52.9 percent. Overburden spoil from the South <br />mine area is expected to have relatively low horizontal hydraulic conductivity values, low <br />infiltration rates, and relatively high cation exchange potentials. <br />Cores from the Seneca II-W South expansion area were also analyzed for a suite of chemical <br />parameters. Results are summarized in Tables 6-4A, 6-7A, 6-76, 6-7C and 6-7D (see Tab 61. <br />No elevated trace element concentrations occur in the overburden from the South mining area. <br />Reported metal/metalloid analyte concentrations vary from less than the detection limit <br />(cadmium, chromium and molybdenum) to 354 mg/Kg (iron). A comparison of average, soil- <br />chemistry concentrations from the II-W and II-W South areas, shown in Table 17-36, Comparison <br />of Mean Weighted Overburden Chemistry for the Seneca II-W/Seneca II-W South Area, indicates <br />that Wadge overburden chemistry in the two Seneca 11-W mining areas is similar. Differences in <br />average analyte concentrations between the two areas vary from 0.02 mg/Kg (selenium) to <br />108.8 mg/Kg (iron). Table 17.36a, Average Overburden Chemistry for Seneca II-W South Sage <br />Creek/Wolf Creek Mine Area, shows that the geochemistry in these units is similar to that <br />observed in the Wadge overburden. As stated previously, meteoric water infiltrating into spoils <br />is not expected to act as an acidic leaching solution. Available chemistry data from both Seneca <br />II-W and Seneca II-W South soils indicate that, even if exposed to an acidic solution, elemental <br />soil concentrations available for dissolution are limited. Therefore, the potential for mobilizing <br />significant trace element concentrations from spoils in either area is minimal. Additional physical <br />and chemical characteristics of the overburden are addressed in Tab 6. <br />103 Revised 1 /02 <br />