PERMFILE101350

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 3/25/2003
• Section_Exhibit Name: NH2 Section 2.04.6 Geology Description
• Media Type: D
• Archive: Yes

• Bore Hole and Core Hole Analysis. Peabody Appendix 6-1 contains numerous lithologic and
geophysical drill logs for the permit area which show and describe the lithologic characteristics and
thickness for each coal seam and associated strata. The location and elevation of these drilling
sites are also provided in the specified appendices. The location of the New Horizon 2 drill holes
for the cross-sections are shown on Map 2.04.6-1, Geologic Cross Section and Sample Locations.
Map 2.04.6-1A shows the locations of the drill holes bored over time in and adjacent to the permit
boundary.
Structure. The New Horizon 2 area is located slightly north of the axis of the structurally simple
Nucla Syncline. Structure contours drawn as the top of the Lower Dakota (#2) coal seam indicate
that the mean coal dip is 4.5 percent southwest and strike N.45° W. Minor local variations in the
attitude of these coals occur due to spuriously trending small folds and penecontemporaneous
depositional features. These slight undulations are best seen in the highwalls and mine floors of
active and abandoned mine pits in the New Horizon 1 area. The outcrop patterns and configuration
of overburden thicknesses are determined by a combination of topography and geologic structure.
Four geologic cross sections, D-D' through G-G', are shown in Map 2.04.6-2 through 2.04.6-5.
Cross sections D-D' and E-E' are oriented approximately parallel to the mean coal strike while cross
sections F-F' and G-G' are drawn nearly parallel to the mean coal dip. These cross sections
• illustrate the simple structural relationships existing in the New Horizon 2 study area.
Faults were not observed during the course of mining at New Horizon 1. According to Cater (1955),
faults are generally absent along the axial portions of synclines in the Salt Anticline Region.
However, faults with relatively small displacement, (several feet), are encountered occasionally
while mining in the New Horizon 2 permit area.
Stratiuraphv. With the exception of unconsolidated Quaternary deposits, the only exposed
formation at the mine site is the Dakota sandstone. The general lithologic characteristics of this
formation were described in the section on Regional Geology. This section discusses the
site-specific stratigraphy as derived from drill hole descriptions and field examination of highwalls
and road cuts.
Figure 2.04.6-1, Generalized Columnar Section of the Dakota Sandstone at the New Horizon 2
Study Area, and Maps 2.04.6-2 through 2.04.6-6, Geologic Cross Sections, show the complex
lithologic relationships within the study area. Maps 2.04.6-3 has been extended and cross section
H-H' has been prepared tc cover the adjacent New Horizon Mine 2 permit area for this revision.
• Revised 27 Aug 2002 3