2016-06-08_PERMIT FILE - C1982056A

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NW Mains Ventilation Fan Sound Deflector/Absorber (MR05-192) As part of TCC's ongoing efforts to minimize potential mine impacts on area residents, a sound deflector/absorber unit will be installed on the NW Mains Ventilation Fan. The unit is designed to deflect fan exhaust, and to both absorb and deflect any associated sound approximately 90 degrees from its current discharge direction. Installation of the sound deflector/absorber unit will require construction of foundations utilizing concrete piers and concrete grade beams. The foundation will consist of twelve concrete piers (12 -inch diameter x 15-21 feet deep), supporting two curved reinforced concrete grade beams (12 inches wide x 2 feet deep x 31-64 feet long), with a reinforced concrete slab between the grade beams. Two concrete piers will be poured on either side of the foundation to provide for side - bracing of the sound deflector/absorber structure. The sound deflector/absorber unit will be a fabricated curved steel structure, lined with sound absorbing material, approximately 12 feet wide x 20 feet high x 45 feet long (along center- line of curvature). Installation of the sound deflector/absorber unit will be on the existing NW Mains Ventilation Fan pad and will not involve any new disturbance. The location and configuration of the unit is shown on Map 24 and Figure 31. As a passive sound control device, the only required maintenance will involve periodic inspection and cleaning. When the unit is no longer needed to control sound emissions from the ventilation fan, it will be removed and will either be re- used elsewhere or salvaged. Foundations will be demolished and removed in conjunction with demolition and restoration of the ventilation fan installation. 18-Ri2ht Ventilation Shaft (TR 04-44, TR05-50, MR04-190, MR05-200, MR07-225, MR08-229) As mine development has proceeded to the north, the distance from existing mine ventilation fan installations has increased to the point where an additional intake ventilation shaft is necessary to maintain effective ventilation of active mining areas. The new ventilation shaft is located adjacent to Fish Creek in Section 10, T5N, R86W on a low rise above the Fish Creek drainage, as shown on Maps 23 and 23B. Development, construction, and installation of the ventilation shaft and fan installation (Figures 30 and 30a) involved the following sequential activities, as briefly described in the following sections: • Completion of environmental and engineering investigations • Placement of disturbed area markers • Marking of stream and wetland buffer zone • Temporary drainage and sediment control measures • Recovery and stockpiling of available topsoil • Installation of drainage and sediment control structures • Construction of an access road and site preparation for shaft pad • Drilling of shaft pilot hole and grouting operations (as necessary) • Construction of temporary power • Construction of shaft collar structure and temporary drilling equipment pad • Shaft boring and casing operations • Erection of escape hoist buildings and equipment and installation of fence(s) • Installation and connection of escape hoist control equipment and systems • Installation of shaft heater and associated ancillary equipment • Driving of additional entries at the back of the 18 Right longwall panel • Boring and casing of Mine Atmosphere Control boreholes, and installation of modular methane drainage and nitrogen injection systems • Final clean-up and dressing of roads and site pads Site-specific investigations required for design and permitting of the new ventilation shaft included a cultural resource survey of potential disturbance areas, soil and foundation characterization as the basis for shaft pad and access road design, and completion of a wetland/AVF survey for the shaft pad and access road. The cultural resource survey was conducted by Metcalf Archaeological Consultants, the engineering soils characterization by Northwest Colorado Consultants, and the soils/wetland/AVF survey by Habitat Management, as described in Section 2.04. MRI 1-259 2.05-45.4 11/17/11