2011-03-24_REPORT - C1981019 (10)

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2.0 RESULTS 2.1 Overall Summary Overall, a total of 66 plant species were observed within the seven older revegetated areas, consisting of 25 grasses, 35 forbs, one sub-shrub, and five shrubs. The reference areas displayed 47 plant species, 17 grass taxa, 22 forbs, two sub-shrubs, and six shrubs (Table AB-1 in Appendix AB). On average, 35 unique plant species are observable in any given revegetation unit and 30 in the reference areas. Among these taxa are occasional noxious or invasive weeds such as Canada thistle or Japanese brome (and/or cheatgrass), with the latter occasionally existing as more notable patches. In 2010, there were two first-year units evaluated for emergent seedling density, while the seven remaining units exhibit seven or more growing seasons. An analysis of the ground cover variable (Chart 1) indicates that only three of the seven areas of older reclamation (7 or more years of age) exceed the success criterion based on 2010 reference area values. Elevated levels of annual grasses contributed to the inability of the remaining units to pass the success criterion (Chart AB-1). It should also be noted that the four units that did not pass are seven years old and perennial cover should continue to improve with more time. Table 1 and Chart 2 indicate success with regard to production for all older reclaimed units. Production data are not collected from younger areas. All units evaluated for current annual production (7 or more years old) easily passed the success comparison. With regard to diversity, the approval of TR-72 (and TR-82) has changed the standard for pre-2010 reclamation to at least two perennial grasses with between 3% and 50% relative cover and all forbs (excluding noxious weeds) combined to contribute between 1% and 50% relative cover. Colowyo's revegetation efforts have been successful in meeting these new diversity standards on the seven older reclamation units sampled in 2010, as indicated on Table 2 and Charts 3 and 4. The approval of TR-72 provides a more suitable success comparison for woody plant density at the Colowyo Mine. The newly established success standard requires 150 woody plants per acre on 3% of the land on all pre-2010 reclamation. This standard is primarily achieved on Colowyo's reclamation by quantifying establishing shrub units. These units usually span more than one reclamation unit while entirely missing others, eventual shrub patches are a result of a number of environmental (timing of precipitation, snowpack, competition, etc.) and managerial (soil depth, seeding, etc.) factors. Reclamation units are typically combined to provide logical parcels for bond release evaluation. For the purpose of ascertaining progress towards bond release, the number of shrub-qualified acres in each unit is presented on each corresponding compendium. However, several of the evaluated areas have not been evaluated for shrubs as yet because they were too young during the last shrub mapping/counting exercise. These units, among others, are scheduled for mapping/quantification in the spring of 2011. Cedar Creek Associates, Inc. 5 Colowyo Mine 2010 Revegetation Monitoring Report