2007-01-31_REVISION - M1986015 (2)

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i sediment to meet the requirements of the NPDES permit. Therefore, step dams may be needed at intervals I along the drainage to reduce the velocity of the water and reduce sediment loads before the water reaches the river at the designated discharge p int. MINING PLANS I Under this major heading of [his exhibit [he actual mining plans are presented. The first section discusses the aspects that have been changed in the original plan for Phase 1 as well as what the future plans are for that area. As mining is approaching completion in Phase 1, the first section is fairly simple. The second section deals with) [he plans for Phase 2. The arrangement in the Phase 2 plan is, as much as possible, sequential. That is, the first steps that need to be done are presented first. This is followed by the second step, third, etch. This arrangement seems to be the easiest way to present a plan that has some rather complex aspects. I Mining Plan Changes Applicable to Phase 1 Requirement: Phase 1 will remain basically as originally designed with respect to the area of mining and [he direction of mining) However, [he slurry wall installation at the end of Phase 1 has I been deleted from this plan. I Requirement: Phase 1 will be back~filled using a series of sediment basins. Wash fines in combination with overburden and soil shall be used to backfill Phase 1. I DISCUSSION: As shown Ion Exhibit C-4A (Amendment 3): Phase I Detail Mining Plan, the I entire area will become a series of se[Eling basins separated by barrier walls. On this map these have been arranged so no single basin is completely closed. That is, water contained in the fill will be able to escape I to [he surrounding unmined areas through at least one pathway. Although it is not expected that wash fines can possibly fill the entire area, overburden from this area as well as Phase 2 should be able [o fill the area sufficiently so that exposed groundwater is not a problem. As described in Exhibit E - Reclamation Plan, this area will evenkually be capable of supporting a rich riparian forest habitat I intermingled with occasional wetland areas, Over most of the area the fill will be to an elevation between one-half and three feet above the expiected groundwater elevation so as to introduce a diverse habitat and prevent monocultural vegetation dev ~lopment. It is expected [hat the plant site will remain after the I operation, but if additional fill is needed the large volume of overburden used to construct that platform I can be used as backfill Pueblo East Pi[ Amendment 3 (2007) Exhibit D Page 21 of 34