2010-12-17_REVISION - C1981019 (106)

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RULE 2 PERMITS If the initial minimum number of samples in each area did not provide a suitable estimate of the mean 18 (i.e., the inequality was false), additional samples were collected until the inequality (nmin < n) became true. Only two areas required additional sampling (Juniper Scrub and Bottomland Baseline Areas) where 39 and 17 additional production samples were collected. Reference Area Comparability - When reference areas are utilized as revegetation standards of success for vegetation cover and production, demonstrations are required prior to permit issuance to document that the selected reference areas are statistically comparable (equal) to the vegetation types for which they represent. The pre- mining demonstration of reference area comparability was made using the two- tailed Students t -test as indicated below. Reference area production and cover are compared at the 95 percent confidence limit (alpha at 0.05 level) with the respective baseline area production and cover. The sample "t" statistic (t *) is calculated as follows: t * =(x, — x +(s where: x, = mean of the baseline area x Z = mean of the reference area S = variance of the baseline area S Z = variance of the reference area n = sample size for the baseline area n = sample size for the reference area The tabular "t" comparison statistic (t' ) is calculated as follows: t', , = [(s12 /n,)ta, + (S22 1n2)ta21l(s,2 /n, + s /n where : O = 0.05 level Then if the inequality (t* < t' is true, the test is passed and the baseline and reference areas can be considered to be from identical populations. Results Detailed Vegetation Information General - Six major vegetation community types were identified within the Vegetation Study Area: Aspen, Sagebrush, Bottomland, Grassland, Juniper Scrub, and Mountain Shrub. Minor vegetation communities and land use types included: Improved Pasture, Cultivated Land (Cropland), Disturbed Areas, and Wetlands (acres of wetlands and waters of the U.S. are included under the Bottomland vegetation community type). The acreage occupied by each type /subtype are indicated in Table 2.04.10 33. A vegetation community is termed minor if it is less than 10 acres in total, or it contributes 5 percent or less to the total acreage. Meeting the lesser of these two criteria eliminates a vegetation type from specific reclamation planning. • Collom— Rule 2, Page 59 Revision Date: 1/23/09 Revision No.: PR -03