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State Reg. Conclusions Overburden characteristics at the Seneca Mine reflect the depositional environment of coal-bearing strata in this section of the Williams Fork Formation. Significant chemical differences were noted between Wadge and Wolf Creek overburden and between the overburden and underburden sections. The differences were most notable among the parameters pH and sodium. The mean pH level of the Wadge overburden (7.9) was significantly higher than that for the Wolf Creek overburden {6.S). The SAR of the underburden (6.8) was significantly higher than the overburden (1.4). In most instances, normal overburden mixing will effectively dilute and mitigate potentially inimical zones as documented in Table 6-5. However, in the Wolf Creek mining area, selective dragline handling techniques (mixing, segregating/burying acid strata, and/or segregating/topdressing with suitable material) may be required to eliminate unsuitable pH and ABP levels at the regraded spoil surface. Regraded spoil will require a selectively handled suitable spoil topdressing or lime application if surface pH levels are continuously below 5 and ABP values are more negative than -5. The resultant loamy textured spoil will possess suitable physical qualities which are conducive to productive plant growth. The availabke water holding capacity would be moderate (approximately 0.07 to 0.16 inches of water per inch of soil), permeability moderate (about 0.6 to 2.0 inches per hour), and cation exchange capacity low to moderate (8 to 15 milli-equivalents per 100 grams), Since the spoil contains a high percentage of rock fragments, it does not possess desirable seedbed and tillage characteristics. ( The chemical properties of the spoil are also quite favorable. ;~ Nutrient availability should be high in the lJolf Creek areas and somewhat lower in the Wadge overburden areas. Lime or a fi-~7 RP\/1 CPl~ inii iR~