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State Reg. <br />• A-A', B-B', and Cam', are shown in Exhibits 6-4, 6-5, and 6-6. <br />These cross sections illustrate the simple structural relation- <br />ships existing in the areas of active mining. <br />Faults have not been observed during the course of mining. <br />According to Cater (1955), faults are generally absent along <br />the axial portions of synclines in the Salt Anticline Region. <br />It is possible that faults with small displacements exist in <br />undisturbed parts of the permit, but their occurrence is not <br />yet documented. <br />2.04.6(1)(a) D. STRATIGRAPHY. With the exception of unconsolidated <br />Quaternary deposits, the only exposed formation at the mine <br />site is the Dakota Sandstone. The general lithologic char- <br />acteristics of this formation Here described in the section <br />on Regional Geology. This section discusses the site-specific <br />stratigraphy as derived from drill hole logs aril field exami- <br />• nation of highwalls and road cuts. <br />Figure 6-2, Generalized Columnar Section of the Dakota Sand- <br />stone at the Nucla Mine, and Exhibits 6-4, 6-5, and 6-6, <br />Geologic Cross Sections, show the canplex lithologic relation- <br />ships within the permit area. Figure 6-2 was prepared using <br />information obtained by a field geologist during the fall of <br />1979. Stratigraphic correlation of individual driller's logs <br />in Exhibits 6-4 through 6-6 proved to be difficult, and at <br />times, confusing because of the wide variation in driller's <br />terminology. Only the principle stratigraphic units (i.e. <br />coal seams, sandstones, etc.) were correlated in these cross <br />sections. <br />The two coal seams being mined are the #1 or Upper Dakota Coal <br />Seam, and the #2 or Locaer Dakota Coal Seam. These seams lie <br />within the "middle" Dakota lithologic unit described by Young <br />r1 <br />L_J <br />6-13 <br />