2010-03-12_REPORT - C1981019 (8)

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2.0 RESULTS 2.1 Overall Summary overall, a total of 62 plant species were observed within the 6 revegetated areas, whereas 43 plant species were observed in the 2 reference areas evaluated in 2009. These consisted of 25 grass taxa, 31 forbs, 1 sub-shrub, and 5 shrubs in the revegetation and 16 grass taxa, 18 forbs, 2 sub-shrubs, and 7 shrubs in the reference areas (see Table AB-1 in Appendix AB). Table AB-1 indicates all taxa observed during fieldwork and is the only table that indicates 1) common names, 2) historic scientific nomenclature, and 3) most current taxonomic nomenclature. Remaining tables do not indicate this latter category. On average, 32 unique plant species are observable in any given revegetation unit and 28 in the references areas. Among these taxa are an occasional noxious or invasive weeds such as musk thistle or Japanese brome (and/or cheatgrass), with the latter occasionally existing as more notable patches. In 2009, there was one two-year unit, one four-year unit, and four units that exhibit seven or more growing seasons. An analysis of the ground cover variable (Chart 1) indicated that three of the four areas of older reclamation (7 or more years of age) exceed the success criterion based on 2009 reference area values. The exception is EP042 which does not pass the 2009 standard, because in 2002 it was seeded with a shrub only seed mix, and it currently exhibits high annual brome cover. EP047 and EP046 exhibiting two and four years of growth, respectively, also did not pass the reference area based success criterion. However, these areas are young and will likely develop as they get older, although, there are some notable patches of annual bromes in both units. On the other hand, Table 1 and Chart 2 indicate success with regard to production on all four of the revegetated units that are 7 or more years of age. Production data are not collected from younger areas, but eventual success is readily expected. With regard to diversity, the approval of TR-72 has changed the standard for pre-2010 reclamation to at least 2 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 are successful in all six units sampled in 2009 including the two and four year old units, 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 mainly 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. CEDAR CREEK ASSOCIATES, Inc. Page 5 Colowyo Mine 2009 Revegetation Monitoring Report