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10 <br />for each bond release Block and for the three reference areas. CYCC used an acreage-weighted <br />approach to determine revegetation success. Vegetative cover values from pasture reference <br />areas (native pasture, dryland pasture, and low sage pasture) were averaged based upon the <br />proportion of respective pre-mining plant communities disturbed by minim. <br />Review of the vegetative cover data collected in 199 finds that the vegetative cover of the North <br />Block exceeded the vegetative cover of the acreage-weighted pasture reference areas. The North <br />Block measured 56.66 % herbaceous cover while the acreage-weighted pasture reference areas <br />measured 47.14% in 1995. Cover data were collected to statistical adequacy. Since the <br />reclaimed area cover exceeded that of the acreage-weighted reference areas, no other statistical <br />analysis was necessary to demonstrate Phase II revegetation success. <br />Due to the timing of sampling, the pasture reference areas were sampled twice. Reference areas <br />were sampled from July 17, 1996 through July 23, 1996 to coincide with sampling conducted in <br />the North Block. Sampling of the South Block was conducted from July 24 through July 31, <br />1996. Reference areas were sampled August 1, 1996 though August 5, 1996 for comparison to <br />the South Block data. <br />The South Block herbaceous cover exceeded the acreage-weighted pasture reference areas in <br />1996. The South Block was measured at 49.95% herbaceous vegetative cover versus 42.35% <br />herbaceous vegetative cover in the pasture reference areas. This value did not include annual and <br />biennial species, "undesirable fortis", or noxious weeds. The South Block vegetative cover value <br />exceeded the cover value of the acreage-weighted reference areas for the 1996 data. <br />The seed mix used was composed primarily of introduced forage grasses, with two legumes <br />(Alfalfa and Cicer milkvetch), that provided a suitable pasture mix for cattle. Limited patches of <br />Canada thistle (Cirsie~m arvense) are concentrated in the damp spoil spring aeeas. Sporadic <br />patches of White [op (Cardaria drabn) were present on the reclaimed areas. Colorado Yampa <br />Coal Company conducted annual chemical weed control to manage these two weedy species. <br />The presence of these weedy species is not extensive nor does it inhibit the post-mining land use. <br />Division personnel have observed cattle grazing on the thistle plants. Sampling data from 199 <br />indicate that 2.25 % of the total cover in the North Block was attributed to noxious weeds. while <br />noxious weeds in the South Block in 1996 accounted for 1.32 % cover. The Division's Noxious <br />Weed Guideline, dated April ]0, 1990, states that noxious weed species should account for less <br />than 3% cover in a revegetated stand. The re-established vegetation on the Energy Mine No. 3 is <br />in accordance with the Division's Noxious Weed Guideline. <br />Colorado Yampa Coa] Company provided site specific vegetative sampling data for the <br />reclaimed and reference areas to develop a single storm SEDCAD+ model to demonstrate that <br />the reclaimed area produces less sediment than in pre-mine condition. Aland-use of pasture was <br />used in this compazison. The results of this comparison indicate that the reclaimed slopes <br />produce less sediment than [he same area in a pre-mine condition, assuming it had a cover equal <br />Colorado Yampa Coal Company: Mine No. 3. SL02 Findines 6/99 a:\C08J062\SL021nd.doc <br />