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• increments. Adjacent two-foot chip samples of similar strata were composited into four-, <br />six-, eight-, or ten-foot vertical increments in the field before shipment to the <br />laboratory. The chip and core samples vere crushed to pass a 70 and/or 20 mesh sieve end <br />begged for s[o re ge. <br />All samples from the four Phase I[ sites were chemically and physically enalyxed et <br />InterMOUntain Laboratory using the procedures listed in Table 4. The parameter end <br />procedure list was developed by Peabody's soil scientist (G. Wendt) in consultation with <br />the Division's reclamation specialist (C. Mount). Extensive reference was made to the <br />Division's 7982 Yater quality and Overburden Geochemistry Guideline (CMLRD, 1982). <br />Overburden Characteristics. Analytical data for the 14 bore and core holes are provided <br />in Appendix b-2. In general, the physical end chemical data generated by the overburden <br />testing ere typical for the 4illiems Fork, Iles, end Lewis Formations which form the <br />Mesaverde Group. atratigraph is units predominantly consist of fine-grained, interbedded <br />sandstone and shales with lesser amounts of sandy shale, siltstone, and coal. Lithologic <br />descriptions for each of the core end bore holes ere presented in Appendix b-7. The <br />• overburden particle distribution shows a high clay, silt, end very fine sand content <br />reflecting the fine-grained nature of the depositional units. Salt levels (i. e., <br />conductivities) are low while pN ranges typically from slightly acidic to mildly alkaline. <br />Nitrate concentrations end SAR values ere consistently law end trace element <br />,\ <br />concentrations are generally et normally expected background levels. ~ <br />The criteria for assessing the suitability of overburden for a root growth medium or <br />aquifer restoration material are es presented in Table 5. The suitability limits for each <br />parameter ere documented by current literature citings. <br />Unsuitable levels were recorded for eleven constituents, pN, acid base potential, iron, <br />manganese, zinc, boron, molybdenum, sodium adsorption ratio, saturation percentage, sand, <br />and clay (Appendix 6.3). Extremely end very strongly acid soil reactions, acid base <br />potential values with more than a 5-ton calcium carbonate per 7,000 tons of spoil deficit, <br />boron values greater then 5 ppm, send levels greeter than 87 percent, end en unsuitable <br />SAR value were dominantly associated with the wedge, Lennox, wolf Creek, end minor coal <br />seems. Unsuitable acid base potential values were also identified with shale end coal <br />• strata located from 20 to 35 feet above the Yolf Creek coal seam. Clay percentages <br />greater Chan 50 percent end saturation percentages greater than 85 percent were <br />associated exclusively with shale strata overlying the Lennox coal seam end also with the <br />23 Revised 03/01/95 <br />