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The two forb species that contributed the most relative cover for 2018 were alfalfa (Medicago saliva) <br />and Western yarrow (Achillea millefolium) with 2.48% and 1.74% respectively. Neither of these <br />species met the relative cover standard outlined in the permit (page 4-121a). However, alfalfa <br />contributed the most relative cover at 2.48% which is .52%, or one half percent, short of the standard. <br />A further review of the application data shows that alfalfa contributed significantly to the composition <br />of the species found at the site in terms of production. It averaged 7.18 g/,/4M2 of the total 46.39 g/,/4M2 <br />produced, or 15.4% of production. Rule 4.15.8(5) allows the demonstration of species diversity to be <br />based on species diversity indices and/or comparisons of cover or production composition of reclaimed <br />land versus undisturbed vegetation. The production standard approved for the Trapper Mine is based <br />on a technical standard derived from historic production at the site. Given that the bond release block <br />greatly exceeded the revegetation success standard for production in 2018 and 2017 and a significant <br />portion of that production was attributed to a perennial forb (Alfalfa), that alfalfa was very close to <br />meeting the permitted relative cover standard in 2018, and it exceeded the diversity standard in 2017, <br />the Division finds that adequate species diversity have been achieved on the revegetated area in <br />accordance with Rule 4.15.8(5). <br />Based on the perennial species of grasses, forbs and shrubs found at the site as indicated in the <br />SL20 application, the species diversity and composition will support the post -mine land use. While <br />noxious weeds were encountered at the site, they comprised a small percentage of the vegetative <br />cover. <br />Post Mining Land Use <br />TMI's objective is to restore the affected areas to the land uses prior to mining as indicated in section <br />4.2 of the permit. There are three significant land uses within the permit boundary: farming, grazing <br />of domestic livestock and use by wildlife. The bond release block does not contain farmland and thus <br />will be used as rangeland for livestock and wildlife. The reclaimed lands have vegetative cover <br />composed of a variety of grasses, forbs, and woody shrubs as described in the above sections. The <br />species, seasonality and forage characteristics of the reclaimed vegetation are suitable for the approved <br />post -mining land uses. The Division has observed livestock grazing and substantial wildlife use of <br />previously reclaimed areas. The revegetation success standards were based on what would be <br />necessary for the land to properly function to accommodate the post mine land uses. Based on the <br />achievement of these requirements, the Division finds that the revegetation on the Trapper Mine <br />reclaimed areas is capable of supporting post- mining land use. <br />Evaluation of Hydrologic Impacts <br />Rule 3.03.2(2) requires the Division to evaluate hydrologic impacts prior to releasing reclamation <br />liability. This evaluation considers whether pollution of surface or subsurface water is occurring and <br />the probability of future occurrence of such pollution. The Division's evaluation is summarized below. <br />Ground Water Impacts <br />TMI monitors the quality and levels of ground water in mine backfill aquifers using wells GD3, <br />GF5, GF7 and GF11. These four wells were not included within the SL20 Phase III bond release area. <br />However, because they are used as ash monitoring wells, they are still sampled and are representative <br />of backfilled aquifer conditions. Historical data from the backfill wells indicate leachate forms in the <br />spoil/ash backfill. This leachate is alkaline, and high in dissolved solids (TDS), mainly sulfates. This <br />concentration may continue for several hundred years, as predicted for the Seneca II Mine in Routt <br />Permit Number C1981010 <br />SL20 Page 12 of 17 <br />