2007-01-31_REVISION - M1986015 (2)

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dense clearing a narrow path through the vegetation may be the only feasible approach [o defining the affected land boundary without risking the possibility of disturbing land too close to [he river. It is often difficult to even see the river bank from a distance of as little as 25 or 30 feet, much less from 100 feet or more. This is especially true along much of the river bank in the Phase 2 area. In these cases, defining this line during the winter or with careful GPS measurements is often useful. The problem with using GPS in thick vegetation during the summer, however, is that the dense overhead leaf cover can absorb much of the energy in the weak radio signals from the satellites and result in greatly reduced accuracy, even when using highly sophisticated GPS equipment. In summer, as difficult as i[ maybe [o do, actual measurements should be used to set the boundary rather than relying on GPS equipment. Requirement: No disturbances between the affected land boundary and the river are allowed other than the streambank stabilization work described in this plan. No soil or overburden can be stockpiled or placed for other purposes in the river setback zone. DISCUSSION: The affected land boundary is defined to exclude all land within the setback from the river. No disturbance, including the stockpiling of overburden or soil, can be made within the setback zone. This setback zone varies slightly in width depending upon [he location relative [o the river. In no case is the setback zone less than 100 fee[ from [he river, but in other cases it is a bit more. This boundary has been set primarily by the characteristics of the land adjacent to the river. If there are wetlands or small channels that carry water during high or even moderate flows the landward side of those edges are usually considered the functional edge of the river. It is critical to maintain the tree cover in [he setback zone in as good a condition as possible. Placement of material around the base of the trees will likely kill [he trees. Without [he trees [here is an increased probability [hat the river could erode into the mined area and eventually threaten the south side of the groundwater barrier wall after it is constructed. Unfortunately, as discussed elsewhere, even with the trees there is no guarantee such erosion will not occur. But good tree cover and a well vegetated bank, especially with dense willows, reduces this possibility. The only disturbances that can be made in this setback zone are those needed to construct any streambank stabilization structures. This is addressed elsewhere in this plan. PHASING: Requirement: The eastern edge of this mining operation is the eastern edge of Phase 1 as shown on the maps. The Phase 2e area shown on the maps for Amendment 1 no longer exists and is not included as a par[ of [his plan. Pueblo East Pit Amendment 3 (2007) Exhibit D Page 13 of 34