2008-06-09_REVISION - C1980007 (3)

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Soils • • • Table 3-3 Maximum Acres Disturbed by Soil Map Unit Under the Proposed Action Alternative 2 Alternative 3 Soil Map Unit Number Road Construction' MDW Drilling Ventilation Shaft ~ Consh•uction Staging Areas2 Road Construction MDW Drilling Ventilation Shaft 1 Construction Staging Areas2 111 0 0.8 0 0 0 0 0 0 116 2.5 4.8 4 .63 2.51 4.8 4 0.63 124 5.4 18.4 0 0.38 4.03 12.8 0 0 130 0.51 1.6 0 0 0 0 0 0 131 0.08 0 0 0 0.08 0 0 0 153 0.06 3.2 0 0 0.06 3.2 0 0 157 2.6 4.8 0 0 2.56 4.8 0 0 158 44.2 78.4 0 0.47 43.21 70.4 0 0.47 185 5.9 15.2 0 0.99 5.82 12.8 0 0.99 188 18.1 24 0 1.4 16.73 17.6 0 1.4 189 2.7 3.2 0 0.25 07 0 0 0 200 8.3 27.2 0 0 8.31 25.6 0 0 Notes Acres can not be totaled because they are double counted. Numbers reflect the maximum for each soil map unit, depending on the final location of the roads and well pads. ~ New and upgrades roads. 'Does not include staging areas that are located at MDW sites. plans, existing coal-related approvals and non- coal related activities would continue to occur and/or guide management of the project area. Mining-related effects would be limited to reclamation and disturbance from surface resource monitoring activities such as installation of monitoring wells, surface water monitoring stations, etc., and would occur sooner than anticipated based on leases. Alternative 2 Increased soil erosion could be expected from areas disturbed by construction activities. Most soils in the project area have high erosion hazard ratings when located in steep areas. Figure 7 identifies limited areas were road corridors and MDW pad windows intersect areas with slopes greater than 60 percent. Lease stipulations and design criteria (Table 2-1) specifically state no surface occupancy will occur in areas with slopes greater than or equal to 60 percent and areas with moderate geologic hazard (i.e., unstable slopes) would require site analysis and mitigation plans. Furthermore, sediment control measures including interim revegetation would decrease the soil erosion potential on disturbed areas. Due to the aforementioned stipulations and criteria, and the latitude of facility placement within the identified road corridors and MDW pad windows, placement of facilities would not be expected in areas with slopes greater than 60 percent or in areas of high geologic hazard, despite the potential for small scale, short term slope instability and limited soil erosion. Subsidence could aggravate existing landslides and stimulate new landslides especially if it occurs at the toe of slopes that are close to equilibrium, as this may be enough to release a weak portion of the slope. Disturbances related to road building could also trigger additional slope movement. Landslides are a form of erosion, if project related activities resulted in Deer Creek Ventilation Shaft and E Seatn Methane Drainage Wells FEIS 77