2020-10-27_PERMIT FILE - C1981035 (23)

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ENVIRONMENTAL ASSESSMENT sec. 26, N1/2NE1/4NE1/4, SW1/4NE1/4NE1/4, NW1/4NE1/4, N1/2NW1/4, N1/2SW1/4NW1/4, SE1/4SW1/4NW1/4, and SE1/4NW1/4; sec. 27, NE1/4NE1/4 and SE1/4NW1/4NE1/4. The area described contains 2,462.07 acres. 2.2.2 Access to the LBA Coal in the LBA area would be accessed from the West Mains (an underground main haulage road) of the King II Mine through a subsurface, low-cover crossing located within the existing OSMRE permit area beneath UMU Tribe acquired lands.The existing King II Mine and the LBA coal reserve area are separated by East Alkali Gulch (the Gulch) where most of the coal outcrops occur. At the southwestern end of the OSMRE Permit area and the western end of the existing West Mains, the coal outcrops just below the valley surface beneath the alluvium and this is where the low-cover crossing would be constructed (Appendix A, Figure 2-1). Access for construction of the low-cover crossing would be located on existing improved and unimproved gravel roads starting at State Highway 120 on State lands approximately three quarters of a mile east of the existing surface facilities (Appendix A, Figure 2-1). The route would follow existing roads and no road improvements would be needed such as widening or other surface disturbance outside the existing disturbance anywhere along the entire construction access route. Grading of the route within the existing road disturbance may be required in some specific areas to allow safe passage of construction vehicles. The low-cover crossing would have three entryways' (an underground horizontal passage used for haulage and ventilation) (Diagram 2-1). The low-cover crossing would be constructed starting from the western end of the existing West Mains. The current conveyor system and ventilation system would then be extended into the new workings to the north through the new underground entryways. During construction activities for the entryways, up to 10 acres of land surface in the Gulch could be temporarily disturbed and then reclaimed. The entryways would be constructed of corrugated steel, multi-plate arches, buried beneath the surface across the Gulch to form what would be analogous to three very large buried half culverts (Diagram 2-2). The crossing would consist of three declines(i.e.tunnels angled downward)constructed from the existing workings on the eastern side of the Gulch down to an elevation of 7,425 feet (ft) at the edge of the valley floor, close to the contact between the valley alluvium and bedrock(Diagram 2-3). ' MSHA may require GCCE to construct four entryways rather than the three proposed and shown on the diagrams. Diagram 2-1 depicts a preliminary engineering design for analysis purposes and will be refined when the final engineering design would be prepared and approved by MSHA and OSMRE.All proposed surface disturbance for the construction of four entryways would occur within the same maximum 10-acre footprint as for the three proposed entryways. Dunn Ranch Area Coal Lease by Application COC-78825 and Mine Plan Modification EA 2-2