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<br />Vegetation Shrdy: New Horizon Mine, NawAirport Reverence Area (Dryland Pasture) <br /> <br />where <br />N=;, =minimum sample s¢e <br />s =sample standard deviation <br />t = single tailed t-value at the 90% confidence interval (alpha = 0.10), with infinfte <br />degrees of freedom (t = 1.645) <br />d =desired level of reduction al»ut the sample mean (0.10) <br />x =sample mean <br />This tormula was approved for this study by Colorado Division of Minerals and Geology (CDMG) <br />botanist Janet Binns in June 2005 (personal communication with Steve Boyle, BIO-Logic <br />Environmental). For sample adequacy calculation in the cover, measuremems of total live <br />perennial vegetation (exduding state-listed noxious weeds) were summed in the field for each <br />trensed, and entered in a Microsoft Excel spreadsheet on a laptop cemputer, which calculated <br />N„ Y„ according to the above equation. <br />• For each transed, percent cover for each plant spades and substrate type was summed from <br />field data sheets, and sums calculated for unvegetated, noxious weeds, annual grasses, annual <br />forts, shrubs, perennial grasses, and perennial forts. Sums for plant spades groups excluded <br />noxious weed spades. For each substrate type, plant spades, and cover group, the following <br />summary statistics were calculated for the reference area as a whole: mean cover, and relative <br />cover (percent. of total live vegetation cover). <br />Production Measurement <br />Produdion was measured on June 28, 2005. Random sample points were boated in the fleM, <br />using the randomty seleded points and geographic coordinates deseribed.above for cover <br />trenseds. At each sample point, a 3 x 3 foot (9.0 ft) square sampling frame was thrown over <br />the shoulder. All above-ground live vegetation in the sampling frame was dipped and placed in <br />paper bags, sorted by perennial grass, annual grass, perennial fort, annual fort, and shrub. <br />State-listed noxious weeds were not encountered in the plots; if they had been, they would have <br />been excluded from dipped material. Clipped vegetation was oven-dried at 55 degrees C for 24 <br />hours, antl weighed. tNeights were tabulated, cernerted to pounds per aae, and mean and <br />standard deviation or total live vegetation calculated. <br />Sample adequacy was calculated after weights were determined, according to the formula <br />desuibed above far cover. Although the calculated sample adequacy (N,,,i,J was 52, Janet <br />Binns of CDMG stated that 30 production samples would be adequate for this study in the event <br />that N„~, exceeded 30 samples (personal communication with Steve Boyle, 614Logic <br />Environmental. <br />B/6Logfc Enwronmenbl <br />July 2005 <br /> <br />(Revised August 2006) Attachment 2.04.10-4-4 <br />