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MAR-10-03 04:39PM FROM-Henderson Mina 2nd Floor 303 569 2830 T-916 P.003/005 F-637 <br />Letter to Ms. Lurline Underbrink-Curran <br />financial warranty, the amendment proposed to remove this area from our permitted <br />boundary. This change does not impact Henderson's financial warranty. <br />POST-MINING LAND USE AND TREE/SHRUB STOCKING RATE <br />Henderson has proposed to change the post-mining land use to "rangeland" from "open <br />forest". This change has been proposed only to bring Henderson's post mining land use <br />into line with the use classifications recognized by the Division. It is our belief that <br />rangeland is the post-mining land use that most closely matches the "open forest" use in <br />the current permit. In addition, rangeland is consistent with county zoning for the <br />property. The change to rangeland does not, in itself, change our proposed reclamation <br />activities or the financial warranty. <br />I understand your concerns relating to the proposed stocking rate for trees and shrubs <br />included in the amendment. In response, Henderson has requested that this portion of the <br />amendment be deleted for all areas of the mill, except the tailing deposition area. We are <br />convinced, based on our experience and available reclamation literature, that we would <br />have close to a 100% failure rate for trees planted on the reclaimed railing impoundment. <br />It would not be beneficial or economically reasonable to require Henderson to plant <br />seedlings on the reclaimed tailing impoundment given this expected high mortality rate. <br />Instead, we propose to consrnict "islands" of thicker cover oa the tailing impoundment as <br />locations to plant trees and shrubs. This change wiXX affect the financial warranty by <br />reducing the costs associated with revegitation of the tailing impoundment. <br />WET COVER RECLAMATION OF TAILING IMPOUNDMENT <br />In the amendment, Henderson proposed an alternative wet-cover scenario for the tailing <br />impoundment. This alternative was proposed because it represents the current industry <br />standard for tailing impoundment reclamation. Experience at other reclaimed tailing <br />impoundment sites, including some owned by Climax Molybdenum Company and <br />located in Colorado, has shown that dry covers are only successful is very arid climates. <br />Wet covers, on the other hand, have been more successful in climates like that in the <br />Williams Fork Valley. Wet covers were a topic of the ICARD 2000 proceedings, and <br />successful case histories of wet covers at Miramachi, New Brunswick, the Falcanbridge <br />mine, and from the Elliot Lake area of Toronto are available. <br />Ia response to your specific concerns regarding a wet cover: <br />1. Soil types to prevent leachinng out of the end. The tailing impoundment at <br />Henderson leaks. It is not possible under either closure scenario -wet or dry cover - <br />to Eliminate the seepage and leaching though the tailings, regazdless of available soil <br />type. In fact, there is ao closure option that will eliminate the seepage through the <br />tailings. We believe, based on experience at Urad, that the water quality of the <br />seepage would be better under wet closure. <br />2. Dam inlet/outlct structure and longterm maintenance. Climax Molybdenum Co. <br />owns the mill property and is responsible for long term maintenance, water treatment, <br />