2008-10-03_PERMIT FILE - C1982056A (4)

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Areal Extent The permit area of the underground mine, totals approximately 22,447 acres, of which approximately 5,120 acres 1 have been affected in the Southwestern and Eastern Mining Districts. Ongoing mining in the NMD will affect approximately 5,430 acres, and permitted future mining in the WMD will affect approximately 830 acres, resulting in a total affected acreage (surface disturbance, mined, and permitted future mining) over the mine life of approximately 11,880 acres. These areas contain all mineable coal reserves bordered by the 15 percent gradient cutoff line to the east and west and the property line to the south. At the conclusion of mining, approximately 65 percent of all the coal contained within the mineable reserve area will have been extracted (see Maps 7, 8, 9, 9a and Figure 1, Geologic Cross-Sections A-A' through E-E'). Minim Layout The underground mine layout was designed with the objectives of safety, rapid development, optimum access to outlying reserves and maximizing recovery. Numerous physical, geotechnical and operational variables influenced design of the mining layout. Mining activities are bordered on the east and west by lease boundaries, faults, or a 15 percent seam gradient cutoff limit, to the south by a lease boundary and mined-out reserves, and to the north by the a 15 percent seam gradient cutoff limit. Reserve access is by a network of main entries oriented primarily north-south and east-west. Longwall panels are laid-out in all areas where economically recoverable coal has been identified and wherever geologic conditions are compatible with safe and efficient mining operations. The following factors influenced the layout of the underground mine: Lease Boundaries -Limits the extent of mining extension Geotechnical Characteristics -Including rock and coal strengths, jointing, cleating and quality Structural Features -Major fault zones and steep gradients are avoided or crossed selectively Reserve Access -Minimal development and capital cost and optimum men and materials transport Orientation -Mains, sub-mains and panels are oriented to avoid directions that have the potential for instability Water -Inflow and control has been considered through sump location and up-dip development Subsidence -Controlled subsidence is planned over areas of full seam coal extraction Ventilation -Influences the size and number of mine openings. The general mine plan layout and timetable is shown on Map 23. Main entries consist of parallel openings, typically five, but may be increased or decreased in number depending upon conditions, driven on 80-foot centers. The openings are approximately 20 feet wide and separated by 60-foot pillars. Crosscuts are driven to connect the mains every 100 feet. Longwall panels are laid out in 500 to 1,000 foot wide by 3,000 to 20,000-foot long blocks. The blocks are bordered by a 2 or 3-entry system of gate-roads. Atypical mine section layout is shown on Figure 7, Typical Mine Section. Map 23, Mine Plan, represents a general overview of the planned mine layout. The locations and orientation of mains, sub-mains, and panels is subject to change (within the limits of the planned mining blocks) as development progresses, mining conditions change, new technology becomes available, or the land or permitting status changes. In the event conditions (either general or in specific mine areas) are found to preclude effective longwall mining, TCC would utilize continuous mining methods in a manner to achieve the best recovery possible under the circumstances. Every effort will be made, however, to maximize recovery of those reserves compatible with extraction by longwall mining methods. Twentymile Coal Company (TCC) does not plan to conduct underground coal mining operations within the Fish Creek Tipple permit area. TR08-64 2.05.13-1 10/09/08