Laserfiche WebLink
2.2 East Pit <br />2.2.1 EPO37 <br />LPUJ/ is comprised of 21.7 acres of moderately <br />sloping revegetation that has a predominately south- <br />easterly aspect. This unit was seeded in 2002 and J r <br />therefore, has undergone seven growing seasons <br />prior to sampling in 2009. A total of 36 plant taxa <br />were observed in the unit (see Table AB-1). Current <br />annual production across the unit averaged 1,804.3 Shrb ,0.0,,,_ <br />pounds per acre in 2009 with perennial grasses and 1 <br />annual grasses the dominant categories (see 0 <br />Compendium 1). Ground cover in EP037 consisted of `t <br />66.7% live vegetation, 0% rock, 27.3% litter, and 0 m <br />bare soil exposure of 6.1%. Perennial cover across TWO.a TMw. <br />the unit averaged 54.5% with annual and biennial ® m <br />cover averaging 12.2% and noxious weed cover of <br />0.5%. Dominant taxa were thickspike wheatgrass <br />(Agropyron dasystachyum), Western wheatgrass m m <br />(Agropyron smithii), cheatgrass (Bromus tectorum), <br />cicer milkvetch (Astragalus cicet), and streambank <br />wheatgrass (Agropyron riparium) with 17.5%, 13.5%, <br />10.2%, 8.9%, and 4.6% average cover, respectively. <br />Woody plant density was determined from 20 belt <br />transects. Density (Table 3) totaled 4 young and <br />mature stems per acre with a split between rubber , cnas-ua:na <br />rabbitbrush (Chrysothamnus nauseosus) and <br />Wyoming Big Sagebrush (Artemisia tridentata). With regard to diversity, EP037 exhibited five perennial <br />grasses with between 3% and 50% relative cover and relative forb cover of 15.2% (excluding noxious <br />weeds). <br />This unit readily passes cover and production bond release comparisons to the reference areas (see <br />Charts 1 and 2). Unit EP037 currently passes the bond release diversity standard of 2 perennial grasses <br />with between 3% and 50% relative cover and relative forb cover between 1% and 50% (see Charts 3 <br />and 4). This unit contains 0.05 acres of qualified shrub units that will contribute to the woody plant <br />density standard of 150 stems per acre on 3% of the reclaimed land. Shrub patches were delineated <br />using 300 stems per acre as a guideline. Therefore, actual acreage that meets the new standard will be <br />higher. Noxious weed control efforts in this unit should be elevated given several scattered populations <br />of Canada thistle (Cirsium arvense) and musk thistle (Carduus nutans) observed intermittently throughout <br />the unit. There are several large patches of annual bromes scattered throughout the unit as well. <br />Although these bromes currently represent 10.2% cover, down from 22.1% in 2006, these patches <br />should continue to be monitored/mapped to document expansion or continued shrinking. If monitoring <br />reveals expansion, use of the herbicide Plateau is recommended in conjunction with spot reseeding. It is <br />possible this activity could occur as a normal range management practice without resetting the clock (see <br />Section 4.15.7 (5). CDRMS would have to be consulted for specific allowances unless such are currently <br />stated in Colowyo's permit. <br />Unit EP037 exhibits good production, diversity, and perennial cover levels for seven-year old <br />revegetation. This unit does not have a large shrub patch component (0.05 acres). However, several <br />large shrub patches surround the unit and combining these units for bond release will effect a successful <br />woody plant density comparison. Monitoring and control of the noxious weed and annual brome patches <br />is recommended. <br />CEDAR CREEK ASSOCIATES, Inc. Page 12 Colowyo Mine <br />2009 Revegetation Monitoring Report <br />• <br />• <br />• <br />• <br />r <br />r <br />41 <br />r