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• The cross section extension and the new cross section H-H' are based on coal exploration <br />holes drilled by Western Fuels-Colorado during 1993. Figure 2.04.6-1 was prepared using <br />information obtained by geologists, hydrologists, and soil scientists during the baseline studies <br />conducted during 1986 and 1987. Stratigraphic correlation of individual driller's logs in Maps <br />2.04.6-2 through 2.04.6-5 proved to be difficult, and at times, confusing because of the wide <br />variation in driller's terminology. Only the principle Stratigraphic units (i.e., coal seams, sandstone, <br />shale, etc.) were correlated in these cross sections. The principal coal seam being mined is the <br />#2 or lower Dakota coal seam. One localized area of upper Dakota coal (#1 seam), which includes <br />Drill Hole Location 871 E, may be mined in this permit term. These seams lie within the "middle" <br />Dakota lithologic unit described by Young (1973), and are characterized by carbonaceous shale <br />and impure coal with lessor amounts of interbedded sandstone and siltstone. Basically, these coals <br />are high BTU, low sulfur bituminous coals that show good lateral continuity. Each seam shows a <br />well-defined system of vertical to near vertical joints (coal "cleats") at the outcrop. These joints are <br />less evident in core samples indicating a lower porosity than would be expected by outcrop <br />examination. Fractures of this sort are highly anisotropic. <br />The upper Dakota (#1) seam generally ranges from 0.6 to 2.1 feet (partings omitted) in thickness <br />with an average of about 1.2 feet and lies approximately 99 feet from the base of the Dakota. The <br />lower Dakota (#2) seam generally ranges from 4.2 to 6.9 feet (partings omitted) in thickness with <br />. an average of about 5.5 feet and lies approximately 86 feet from the base of the Dakota. There is <br />approximately 7.5 feet of interburden separating these seams within the New Horizon 2 permitarea. <br />A 0.4 foot laterally discontinuous "rider" coal seam is found about 7.2 feet above the upper Dakota <br />coal seam in some parts of the permit area. Two additional coal seams, the Nucla (#3) seam and <br />an unnamed seam, are present in the New Horizon 2 study area. The Nucla seam typically ranges <br />from 1.5 to 3.6 feet (partings omitted) in thickness with an average of about 2.5 feet and lies <br />approximately 56feetfromthebaseoftheDakota. The laterally discontinuous unnamed coal seam <br />generally ranges from 0.5 to 1.6 feet in thickness with an average of about 1.0 feet and lies <br />approximately 24 feet from the base of the Dakota. <br />Sandstone and sandy shale are the predominant lithologies in overburden material within the New <br />Horizon 2 study area. The sandstones are generally fine to medium grained, of low porosity, well <br />cemented, lenticular, discordant, and crossbedded. Most sandstones on outcrop show a <br />well-defined system of iron stained joints and fractures. Continuous horizontal gypsum lenses <br />occur between bedding planes and are prevalent throughout the study area in the 20 foot thick <br />sandstone strata which lies about 40 to 60 feet above the base of the lower Dakota coal seam <br />(Figure 2.04.6-1 and Peabody Appendix 6-1 ). The gypsiferous sandstone is situated within a <br />transitional zone between oxidized sulfate-bearing horizons and unoxidized sulfide-bearing, <br />• Revised 27 Aug 2002 5 <br />