2015-08-31_PERMIT FILE - C1981010A (23)

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(from a linear regression estimate) show a range of from 25 to 64 percent clay in the five samples. In CR220 the overburden layer (64'-109') is estimated to contain 64% clay but is expected to buried since two coal seams lie below it. The overburden layer in CR220 (161'-172') contains an estimated 44% clay and an ESP of 15.6. It is above the lowest coal seam but also adjacent to a layer of sandstone plus siltstone (133'-161') which contains an estimated 10% clay and an ESP of 5.5. These two layers will likely become mixed during mining and the mixed layer should produce an acceptable ESP. In CR222 the overburden layer (150'-184') lies between the two lower coal seams. This layer contains an estimated 35% clay and an ESP of 5.3. However, if some mixing occurs with an adjacent layer (124'-145'), with only an estimated 4% clay and an ESP of 3.3 the mixed layer should allow normal plant growth. Assuming a linear arithmetic effect on ESP if the lowermost 50 /feet of overburden is mixed, • the resulting expected ESP can be calculated as fo'llows: E = X I Y 1 + X 2 Y 2 where: E = expected ESP value of the mixed materials X = depth of any individual strata to be mixed Y = ESP of any individual strata to be mixed therefore: E = (16 ft)(3.3 ESP) + (34 ft)(15.3 ESP 50 ft. E = 11.5 ESP In CR223 the overburden layer (96'-111') contains an estimated 40% clay and an ESP of 17.0. The overburden layer (114'-145' except for coal seams) that lies adjacent contains an estimated 55% clay and an ESP of 17.9. The nearest overbur- den layer with a low ESP (47'-80') is not close enough for convenient mixing. 2-389