2022-09-29_PERMIT FILE - C1980007 ‎(5)‎

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 9/29/2022
• Doc Name: SUBSIDENCE EVALUATION
• Section_Exhibit Name: Exhibit 60E Subsidence Evaluation for the South of Divide and Dry Fork Mining Areas
• Media Type: D
• Archive: No

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DEFINITION OF TERMS

South of Divide Mining Area. The mining area encompasses the E-seam longwall panels located
primarily in Sections 32, 33, and 34 of Township 13 South, Range 90 West of the 6th Principal
Meridian, and Sections 3, 4, and 5 of Township 14 South, Range 90 West of the 6th Principal
Meridian. The panels are identified as E1 to E8 and E15 to E17.
Dry Fork Mining Area. The mining area encompasses the extension of the E-seam longwall
panels from the South of Divide Mining Area into the Dry Fork Mining Area. The area is located
primarily in Section 35 of Township 13 South, Range 90 West of the 6th Principal Meridian and
Sections 1 and 2 of Township 14 South, Range 90 West of the 6th Principal meridian. The panels
are identified as E2 to E6.
Southern Panels Mining Area. The mining area includes the E-seam longwall panels originally
included in the South of Divide Mining Area and some of which were extended into the Dry Fork
Mining Area (E1 to E8 and E15 to E17, as above). The Southern Panels mining area also includes
the B-seam longwall panels (B26 to B29) that will underlie Southern Panels E1 to E5. Throughout
this exhibit, this term will be used to identify what was formerly referred to as the South of Divide
and Dry Fork mining areas.
Apache Rocks West Mining Area. The Apache Rocks West panels refer to the three western
panels in the Apache Rocks Mining Area (as defined in the original Exhibit 60), which are located
in Sections 28, 29, and 30, Township 13 South, Range 90 West, of the 6th P.M. Both B- and E-
seam longwall mining will occur in this area.
Sunset Trail Mining Area. The mining area encompasses the E-seam longwall panels located
primarily in Sections 10, 11, 14, and 15 of Township 14 South, Range 90 West of the 6th Principal
Meridian. The panels are identified as SS1 through SS4.
Critical Mining Width. The width of a mining panel necessary for maximum subsidence to
occur; the length of the panel must also be greater than, or equal to, critical panel width for
maximum subsidence to occur. Critical width (Wcr) commonly ranges from 1.0 to 1.4 times the
mining depth (d).
Subcritical Mining Width. The width of a mining panel less than critical width (i.e., less than
1.0 to 1.4d).
Supercritical Mining Width. The width of a mining panel greater than critical width.