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West Elk Mine
<br />• Protection of Public Parks and Historic Places - 2.05.6(4)
<br />Operations at the West Elk Mine are not located near public parks or historic places; therefore, this
<br />section does not apply.
<br />Surface Mining Near Underground Mining - 2.05.6 (5)
<br />There are no surface mining operations proposed near the West Elk Mine.
<br />Subsidence Survey. Subsidence Monitoring and Subsidence Control Plan - 2.05.6 (6) (a-f)
<br />The extraction of the B Seam coal in the Box Canyon permit area, the B and E Seams in the Apache
<br />Rocks permit area, and the E Seam mining in the South of Divide permit revision area will 'be
<br />completed using longwall mining methods. The resulting disequilibrium due to longwall mining may
<br />result in surface subsidence, dependent on a number of inter-related factors. As stated by Peng in
<br />Surface Subsidence Engineering (1992), "When total extraction is used, it produces a large void in the
<br />coal seam and disturbs the equilibrium conditions of the surrounding rock strata. The rock strata bend
<br />downward while the floor heaves. When the excavated area (gob) expands to a sufficient size, the roof
<br />strata will cave. As a result, the overlying strata continue to bend and break until the piles of the fallen
<br />rock fragments are sufficiently high to support the overhanging strata. At this time, the overlying strata
<br />no longer cave, but bend and rest on the underlying strata. Strata bending in subsidence develop
<br />upward until reaching the surface and forming a subsidence basin. The whole overburden strata and
<br />the surface subsidence basin will further go through a period of compaction and gradually become
<br />• stabilized."
<br />The purpose of this section is to describe on a site-specific basis, and to quantify to the extent feasible,
<br />the various phenomena that are embodied in this definition. This section provides an inventory of
<br />structures and renewable resource lands in the current permit area, which includes the South of Divide
<br />permit revision area, as well as a subsidence survey analysis, potential subsidence consequences, and
<br />the subsidence monitoring and control plan. Table 42 of this section provides a list of symbols and
<br />definitions for commonly used terns associated with subsidence and used frequently in this section.
<br />It is essential to present the meanings of the following terminology relative to understanding this
<br />portion of the permit revision text. To further facilitate an understanding of the areas associated
<br />with each geographic expression, see Map lA (and Figure 1 of Exhibit 60B and Figure 2 of Exhibit
<br />60C, 60D and 60E).
<br />Apache Rocks Mining Area - The Apache Rocks mining area encompasses all of the longwall reining
<br />panels in Sections 26, 27, 28, 29, and 30, TUS, R90W, 6' P.M. See also Map 52.
<br />Apache Rocks Mining urea. East and NA7est Panels - The Apache Rocks west panels refer to the three
<br />western panels in the Apache Rocks mining area which are located in Sections 28, 29, and 30, T13 S,
<br />R90W, 6th P.M. Both B and E Searn ion'-wall mining are plaimed in this area. The Apache Rocks
<br />east panels refer to the four eastern panels in the Apacl.e Rocks mining area (longwall panels 14SE
<br />through 17SE), which are located in Sections 26 and 27, and a portion of Section 35 T13S. R90W,,6th
<br />P.M. Only B Seam mining is planned in this area.
<br />_• Box Canyon Mining Area - This area is designated on Map IA and includes longwall panels 18NE
<br />through 2' )NE located in portions of Sections 10, 11, 13, 14, 15, 22, 23, and 24 T13 )S, R90W, 6t" P.M.
<br />2.05-104 Revised Juiw 2005 PRIO, Rev. A4arch 2006; Rev. April 2006 PRIO; ,i4aj,2006 PRIO, Nov. 2006 TR107, Sep. 2007 PR-12; Feb. 2008PR-12
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