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marginally suitable or unsuitable values were determined for copper, lead, arsenic, zinc, <br /> nickel, cadmium, or mercury. In a few instances, copper and zinc concentrations dropped <br /> below the plant deficiency level . However, ample concentrations are present in the <br /> topsoil and subsoil . Since the aforementioned parameters (Cu, Pb, As, Zn, Ni, Cd, and Hg) <br /> were all at nontoxic levels for Site 870E, they were not determined on samples collected <br /> from the remaining Phase I or Phase II sites. <br /> Mean physiochemical values for each parameter are summarized in Table 6-1-10 for the <br /> entire Nucla East study area. All mean values fall within the suitable and marginally <br /> suitable ranges as outlined by the assessment criteria listed in Table 6-1-3. Overall, <br /> about 83 percent of all overburden and interburden strata has suitable physical and <br /> chemical characteristics. <br /> Sulfur fractionation analyses indicate pyrite comprises only 10 percent of the total <br /> sulfur in the overburden but 45 to 85 percent in Units 2, 3, 4, and 6. Contrastingly, <br /> sulfate comprises 70 percent of the total sulfur in the overburden but only 5 to 25 <br /> percent in Units 2, 3, 4, and 6. Organic sulfur typically comprises between 15 and 30 <br /> percent of the total sulfur for all lithologic units. <br /> Texture and saturation percentage occasionally exceeded suitability levels in the <br /> overburden and underburden material (Appendix 6-5). The underburden predominantly <br /> consists of a very hard, indurated sandstone which typically has a sand texture and low <br /> (less than 25 percent) saturation percentage. These strata will not be disturbed by <br /> mining. Two lenses of white silty shale and soft brownish gray shale occur in the <br /> overburden. This strata occurs in the western half of the study area (Sites 870E, 872E, <br /> 881E, and 882E) and outcrops slightly east of Site 870E. The soft weathered shale strata <br /> typically has a clay texture and high (greater than 85 percent) saturation percentage. <br /> Since these strata occur in thin lenses and comprise only about five percent of the <br /> overburden volume, normal overburden handling by dozers and scrapers will effectively <br /> blend or dilute the unsuitable clay levels to acceptable levels. <br /> Mitigative Measures for Marginally Suitable to Unsuitable Material <br /> Zones of marginally suitable to unsuitable material were identified at each of the six <br /> Phase I and Phase 11 sample locations and are documented by parameter, lithology, <br /> location, and sample interval in Appendix 6-5. Effective mitigative measures will include <br /> 6-1-36 Revised 04/11/88 <br />