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Overburden core holes 284AlOCR and 285A9EQ (see map I-1) are used for discussion to compare overburden and spoil analysis to ensure that mixing of regraded surfaces during spoil regrading was properly accomplished to ensure adequate subsoil composition for plant root growth. The para- meters of discussion are pH, EC, SAR and texture (% clay) as they could be identified as having the potential to be problematic. Core hole 284AlOCR identified samples of cuttings from 42 feet directly above the lowest mineable coal seam as being a potential problem when used as sub- soil (spoil) material (Table I-2). Table I-5 compares the high soil analysis levels recorded in the above-stated 42 feet of overburden mate- rial to the actual soil parameters of adjacent spoils following regrade. It is evident that mixing of regraded spoils and short term natural wea- thering has eliminated any potential spoil problems. i Higher-than-desired values were also reported in core hole 285A9EQ, approximately 14 feet above the lowest mineable coal seam. These values were also reduced when compared to the adjacent spoils in which this material was deposited (Table I-5 ). When comparing other core holes which could be identified as having higher-than-desired soil parameter levels (Table 2 and Map I-1) to adja- cent spoils, similar reductions in spoil parameter analysis were reported. Table I-6 provides a mean and a range of values for select spoil parameters in Ashmore, Derringer, and Enfield pits. Suitability criteria for spoil parameters is provided in Table I-7. Of primary concern to Trapper and CMLRD is the higher-than-desired clay content of overburden and associated spoils. The following discussion and letter should provide ample justification that high clay content soils are not problematic when associated with other soil parameters that reduce their potential hazardous effects. In reviewing Montana, New Mexico, Utah and Wyoming overburden, spoil analysis guidelines, all of these states base soil texture limitations on associated SAR values. On mine spoils with high SAR values, the corres- ponding percentage of clay should make up a smaller percentage of the soil texture (<20Y,). As SAR values decrease, a corresponding percentage of clay composition may increase without concern of dispersion or poten- tial sodium hazard. In Montana, spoils with a SAR of > 11 must meet a suitability criteria of < 35% clay. For SAR values > 14 the clay percent should be < 20%. In New Mexico, SAR < 14 may have a clay component of ) 40%. The Division of Oil, Gas and Mining (DOSM) in Utah has set its SAR unsuitability criteria for soil and overburden at > 12 for fine textured soil materials (clays and clay to am s). _.-~a cont.