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C~ <br />u <br /> <br />2.3 West Pit <br />2.3.1 WP006 <br />WP006 is comprised of 2.03 acres of <br />steeply sloping revegetation that has a <br />predominately westerly aspect. This unit was <br />seeded in 1998 and therefore, has undergone <br />seven growing seasons prior to sampling in <br />2005. A total of 15 plant taxa were observed in <br />the unit (see Table AB-1). Current annual <br />production across the unit averaged 1,551 <br />pounds per acre in 2005 with perennial grasses <br />the dominant category (see Figure 8). Ground <br />cover in WP006 consisted of 57.4% live <br />vegetation, 0.2% rock, 12.0% litter, and bare <br />soil exposure of 30.4%. Perennial cover across <br />the unit averaged 53.2% with annual and <br />biennial cover averaging 4.2%. The dominant <br />taxa were thickspike wheatgrass, Siberian <br />wheatgrass, slender wheatgrass, titer <br />milkvetch, and Russian wildrye with 13.0%, <br />11.8%, 9.0%, 7,6%, and 6.6% average cover, <br />respectively. Woody plant density was <br />determined from 5 belt transects. Density <br />(Table 2) totaled 65 young and mature stems <br />per acre with big sagebrush the dominant <br />woody plant. With regard to diversity, WP006 <br />exhibited 5 perennial grasses and 1 perennial <br />forb with between 3% and 50% relative cover. <br />3 <br />.' <br />vrem~m empire roan muo~.-iaos ~'~` <br />. ~S~~~M ..m......,.r _...-__--- <br />Unit WP006 currently passes the bond <br />release diversity standard of 3 perennial grasses and 1 perennial forb with between 3% and 60% relative <br />cover. This unit also easily passes both the cover and production bond release comparisons to the <br />reference areas (see Charts 3 and 5). This unit does not presently meet the woody plant density <br />standard of 90% of 1000 stems per acre and will probably not meet this in the foreseeable future due to <br />the heavy competitive grass cover. See Appendix AA -Section 7.3 for a discussion on options and <br />recommendations with regard to woody plant density. Noxious weeds and annual bromes appear to be <br />controlled in this unit. <br />At present, WP006 is a good example of an improved pasture grassland community that would <br />contribute to the local system as foraging habitat for wildlife (especially elk), as well as provide a variety <br />of management opportunities for livestock grazing. <br />Kennecott Energy Co. / Colowyo Mine <br />Page 19 <br />Revegetation Monitoring - 2005 <br />