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2.2.2 EP039 <br />EP039 is comprised of 4.1 acres of moderately <br />sloping revegetation that has a predominately east <br />aspect. This unit was seeded in 2003 and therefore, <br />has undergone four growing seasons prior to <br />sampling in 2007. A total of 19 plant taxa were <br />observed in the unit (see Table AB-1). Ground cover <br />in EP039 consisted of 64.3% live vegetation, 0.0% O <br />rock, 25.5% litter, and bare soil exposure of 10.2%. <br />Perennial cover across the unit averaged 27.1% with 8 <br />annual and biennial cover averaging a significant <br />37.2%. The dominant taxa were cheatgrass, 6 p <br />thickspike wheatgrass, and Siberian wheatgrass, <br />with 36.9%, 16.4%, and 2.4% average cover, <br />respectively. Woody plant density was determined <br />from 15 belt transects. Density (Table 2) totaled 0 <br /> <br />young and mature stems per acre. With regard to ® ® • <br />diversity, EP039 exhibited 2 perennial grass and 0 <br />perennial fortis with between 3% and 50% relative <br />cover. <br />_ I <br />Noxious weeds appear to be controlled in this °°07 •~- ~` - - ' } <br />unit, however populations of bull thistle (Cirsium <br />vu/pare) were observed. Annual bromes are present <br />with 36.9% cover and should be monitored in the coming years. If monitoring reveals expansion, use of <br />the herbicide Plateau is recommended in conjunction with spot reseeding. Overall, Unit EP039 should be <br />monitored closely to evaluate if intervention is needed to facilitate progress toward bond release. <br />Rio Tinto Energy America/Colowyo Mine Page 16 Revegetation Monitoring - 2007 <br />