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in the reference area was 2.0% in 2010 and 2.6% in 2011. Plates 13 through 16 in Appendix A display <br />typical vegetation conditions in Sagebrush Reference Area B in 2010 and 2011. <br />Ground cover of the Grassland Reference Area (Tables 1, 12, and 13, and Chart 1) in 2010 consisted <br />of 24.1% live vegetation, 2.9% rock, 22.7% litter, and bare ground exposure of 50.3 %. In 2011, ground <br />cover was measured at 25.5% live vegetation, 2.5% rock, 23.5% litter, and 48.5% bare ground <br />exposure. Perennial cover across the unit averaged 23.3% in 2010 and 24.6% in 2011, with annual and <br />biennial cover averaging 0.8% and 0.9 %, respectively. Dominant taxa detected in 2010 were needle - <br />and- thread, blue grama, and scarlet globemallow with 16.6 %, 3.9 %, and 1.2% average cover, <br />respectively. In 2011, the dominant taxa were needle- and - thread, blue grama, and galleta with 14.3 %, <br />4.0 %, and 2.7% average cover, respectively. With regard to diversity (Table 2), the Grassland Reference <br />Area exhibited one warm - season grass, no cool- season perennial grasses and one perennial forb with <br />between 3% and 40% relative cover in 2010. This area exhibited two warm - season grasses, no cool - <br />season perennial grasses and one perennial forb with between 3% and 40% relative cover in 2011. In <br />this regard, this native reference area would also have failed the diversity standard in both years. Total <br />relative cover for all forbs excluding noxious weeds in the reference area was 6.7% in 2010 and 4.5% in <br />2011. Plates 17 through 24 in Appendix A display typical vegetation conditions in the Grassland <br />Reference Area in 2010 and 2011. <br />3.4 Production <br />Table 3 and Chart 2 presents summarized herbaceous production data from the Hamilton Mine and <br />Tables 14 through 23 present raw data collected in 2010 and 2011. As indicated on these figures, Mine <br />Area No. 1 exhibited a total production of 387.3 pounds per acre, including 344.5 pounds of perennial <br />production (89 %) in 2010 and 431.3 pounds per acre, including 419.0 pounds of perennial production <br />(97 %) in 2011. Noxious weeds contributed a negligible 1.8 pounds per acre in 2010 only and were not <br />included in the total. Mine Area No. 3 exhibited a total production of 397.1 pounds per acre, including <br />204.5 pounds of perennial production (51 %) in 2010 and 259.7 pounds per acre, including 235.7 pounds <br />of perennial production (91 %) in 2011. <br />A modest stand of Russian thistle continues to occupy the central portion of Mine Area No. 3. <br />However, it appears that this "patch" is shrinking in both size and density as desirable vegetation <br />continues to invade from the perimeter and expand from within. This observation is also notable <br />between the two years (2010 vs. 2011) given a 1.16% decline in Russian thistle absolute ground cover or <br />5.6% reduction in this taxon's contribution to composition over this period. As indicated, desirable <br />vegetation is readily observable from within the central "patch" and appears to be expanding dominance. <br />This hypothesis is predicated on the fact that Russian thistle is an early sera) invader that cannot <br />CEDAR CREEK ASSOCIATES, Inc. <br />Page 16 Hamilton Mine - 2011 <br />Phase III Bond Release Evaluation <br />