2003-01-14_REVISION - M1977342 (3)

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culverts, parking lots, the sewage treatment plant and the potable water plant with the associated storage tanks would be included in the total package of structures to remain following post- mining closure of the site. These two buildings meet the ownership criteria of Rule 3.1.11 and will not conflict with the post-mining land use change requested in this section. All other buildings and structures would be removed as provided for in the original and present permit. Accordingly, Henderson is seeking approval to change the post-mining land use on 20 acres of the mine site that supports the two buildings discussed to "Industrial/Commercial". All other portions of the mine site (100 acres) post-mining land use will remain as "Rangeland" as described in Section 2.2 in this Amendment. 2.4 Change in Reclamation Plan and Post-mining Land Use at the Tailings Impoundment; Conceptual Alternative As approved in the original Permit, the current tailing impoundment reclamation plan calls for drying of the impoundment, followed by applications of limestone, 6-18 inches of growth media as a dry cover, fertilization, drill seeding, evergreen seedling or shrub planting, and maintenance fertilization. The FW is premised on this plan. As discussed with DMG staff in several pre- AM-04 conversations, Henderson is developing a plan to change the reclamation plan for the tailings impoundmem. Conceptually, this change would entail elimination of the present plan for a 100 percent dry cover, and installation of a plan that would create a developed water resource over approximately 70 percent of the impoundment with the remaining 30 percent continuing under the dry cover scenario. 2.4.1 Alternative Conceptual Plan A Henderson water resource engineering consultant has developed a conceptual design for closure and reclamation of the tailings impoundment. This reclamation scenario wiH provide both necessary and required long-term hydrological and geoehemical stahility and increased resource economic values over the present plan. The new plan envisions the following: • A developed water storage pool along the west or back side of the tailings impoundment designed in a manner that could be utilized for storage and would promote development of aquatic and wetland habitats. Similar wetland habitats have developed naturally within the seepwater canal site in Henderson Area #20 and over the past 25 years at the Urad tailings impoundments. 7