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Since the initial sagebrush reference area had been shown to be statistically comparable <br />to the premine sagebrush community, Colowyo located another sagebrush reference area <br />which was statistically comparable to the existing reference area. This new (1981) <br />reference area was intensively sampled for herbaceous cover and production, using the <br />same sampling methodologies and statistical tests that were used to compare the present <br />reference area to the premine area. On August 21, 1981 Colowyo submitted revised <br />vegetative data summarizing the results of the selection of an alternative sagebrush <br />reference area. <br />Both the new (1981) sagebrush reference area and old sagebrush reference area were <br />intensively sampled for herbaceous cover and production using the same methodologies <br />and statistical tests as used on all previous vegetative sampling programs with the <br />following two exceptions. For the purpose of sample adequacy, the 90% confidence level <br />has been attained for cover and production, whereas, in the past the 80% confidence level <br />had been attained. For production sampling, a larger 60cm. x 60cm. frame was used <br />rather than the 30cm. x 60cm. frame used to gather baseline production data for the <br />original permit application. The use of a larger frame reduced the sampling variance, <br />thus reducing the numbers of samples needed to achieve sample adequacy. <br />For the locations of the current (1981) Sagebrush Reference Area, (1980) Mountain <br />Shrub Reference Area, and (1984) Aspen Reference Area, refer to Map 3, Regional <br />Vegetation. The Sagebrush Reference Area is located north of the office / warehouse <br />complex in the west 1/2 of Section 34, T4N R93W. The Mountain Shrub Reference Area <br />is located on the crest and both east and west slopes of a ridge west of West Pit in the NE <br />1/4 of the NE 1/4 of Section 8 and the NW 1/4 of the NW 1/4 of Section 9, T4N R93W. <br />The Aspen Reference Area is located approximately 4 miles to the SSW of the South <br />Taylor Area in the SE 1/4 of Section 1, T2N R94W and the SW 1/4 of Section 6, T2N <br />R93W. <br />Currently the reference areas are located in an area where grazing can be managed in <br />accordance with the approved postmining land use. <br />Comparisons of weighted averages between reference areas and revegetated areas under <br />Subsection 4.15.7(4) (b) and Subsection 4.15.11 may be utilized to determine <br />revegetation success. Similar methodologies and statistical tests used to compare <br />premine and reference areas will be used to compare reference areas and revegetated <br />areas. For weighted comparisons of original permit area revegetation (grazinglands), <br />reclaimed area data will be compared against 55% Mountain Shrub Reference Area and <br />45% Sagebrush Reference Area data. However, some comparisons may be made directly <br />against a single reference area (e.g., Sagebrush Reference Area). In this regard, any <br />sagebrush steppe community that evolves in the reclaimed area will be directly compared <br />against the 1981 sagebrush reference area. For weighted comparisons of South Taylor <br />revegetation, reclaimed area data will be compared against 52% of the 1980 Mountain <br />Shrub Reference Area, 25% of the 1981 Sagebrush Reference Area, and 23% of the 1984 <br />Aspen Woodland Reference Area data. <br />4.15-13 Revision Date: 3/14/08 <br />Revision No.: TR-72