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• Sample locations in reclaimed areas were randomly plotted by use of an internal script routine <br />within ArcView software. Minimum spacing between sample points was 170 feet (one 50 m <br />transect length). The SCC-assigned numbers of samples for a given parameter in a given area <br />reflected previously experienced sample variability or the level of precision required in a given <br />area. In the extended reference areas, each reference unit was gridded and numbered. Grid cell <br />size was 200 feet X 200 feet. These grid cells were placed contiguously by hand on maps of <br />1:4,800 scale. Sample locations were selected as the center points grid cells selected using <br />random numbers generated by computer. <br />Sample points were located as accurately as possible in the field using aerial and topographic <br />maps and pacing from known locations. Cover and woody density transects were located and <br />oriented using a blind throw of a meter stick. Final location of each herbaceous production plot <br />was accomplished with a blind throw of the sampling hoop made from the origin of the associated <br />cover/woody plant density transect. At each cover/woody plant density sampling location, the <br />slope (percent) and aspect of the site (in degrees not corrected for magnetic declination) were <br />determined and recorded, as was the orientation of the transect (in degrees not corrected for <br />magnetic declination). <br />Sample Adequacy Calculations <br />Sample adequacy calculations parameter estimation without hypothesis testing were carried out <br />using the formula as prescribed by the Colorado Mined Land Reclamation Board for parameter <br />estimation without hypothesis testing (CMLRB) (1995): <br />t2 SZ <br />Nmin= ----------- <br />• (d X ~2 <br />where: <br />fa =one-tailed t-value with (n-1) degrees of freedom, a=0.10 <br />s~ =sample variance <br />d = 0.1 (level of precision or desired detectable reduction) <br />x =sample mean <br />Confidence Limits <br />Confidence limits for comparisons to reference areas and technical standards were calculated <br />using a 1-tailed t-value for alpha error probability of 0.10 at (n-1) degrees of freedom multiplied <br />by the standard error of the mean of the sampled area. <br />C.I. = t, s <br />Jn <br />Performance Standards <br />COVER and HERBACEOUS PRODUCTION : For purposes of comparison only, cover and <br />herbaceous production performance standards were calculated in accordance with procedures <br />