1988-04-11_PERMIT FILE - C1981008A (4)

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al . , 1981 and Munshower, 1983) . Lead concentrations of overburden and interburden material from Phase I samples never exceeded 10 ppm (Tables 6-6 and 6-7; Figures 6-3 and 6-7) . This is an order of magnitude less than what is considered to be excessive. No additional lead analyses are warranted at Nucla Mine. Zinc. For normal growth, most plants generally require a minimum zinc concentration of 1 ppm while zinc related toxicity occurs at 70 ppm. Mean zinc levels of overburden and interburden material (for Phase 1 samples) are 4.9 and 4.7 ppm, respectively; slightly above deficiency levels and well below excessive (Tables 6-6 and 6-7; Figures 6-3 and 6-8) . Twinned sample results from recored offset holes for sites 695E and 697E presented in Appendix 6-4 showed that the initial samples were contaminated. No additional zinc analyses are justified for Nucla Mine. However, zinc analyses were highly recommended for site 873E during Peabody's April 10, 1986 meeting with CMLRD. Therefore, zinc analyses were completed on all samples collected from site 873E. Nickel . Nickel toxicity problems are restricted to poorly drained very acid soils, soils derived from serpentine parent materials or soils that have been contaminated near smelters (Munshower, 1983 and Barth et al . , 1981) . Normal plant available nickel concentrations in soil are slightly less than 2 ppm (Barth et al . , 1981) . Overburden and interburden nickel concentrations in Phase I samples collected at Nucla Mine were 1.0 and 1.5 ppm respectively (Tables 6-6 and 6-7) . All nickel values were well below toxicity levels (Figures 6-3 and 6-8) . No additional nickel analyses are warranted at Nucla Mine. However, nickel analyses were highly recommended for site 873E during Peabody's April 10, 1986 meeting with CMLRD. Consequently, nickel analyses were completed on all samples collected from site 873E. Manganese. Manganese toxicities have been documented in poorly-drained alkaline soils and extremely acidic soils with pH levels below 5.0. Manganese concentrations at Nucla are generally less than 30 ppm but were higher in the more acidic interburden at site 2C (Tables 6-6 and 6-7; Figures 6-3 and 6-8) . A manganese value of 107 ppm was also recorded for the 15 to 20 foot sample increment at site 3C. This site is located outside of the projected mine disturbance area . Manganese 6-34 Revised 3/6/87