Laserfiche WebLink
2.2 FIELD SAMPLING <br />2.2.1 Timing <br />Field investigation of the reclaimed areas was undertaken during the period between June 15 <br />and 28, 2020. This time period coincided with anthesis and maximum presence of the majority <br />of plant species found in the pre-SMCRA reclaimed areas at the mine and adjacent native areas. <br />2.2.2 Total Live Vegetation Cover <br />Total live vegetation cover was estimated by the use of the point -intercept method. An ocular <br />point frame (ESCO Associates) was used to minimize instrument error and maximize precision <br />and observer accuracy. Cover transects were 25 meters in length, with two sample data points <br />collected at 1.0 meter intervals along the transect on opposite sides of the transect centerline, <br />1.5m apart. Transect direction was established randomly through the use of computer <br />generated random directions (0-360°). In no event were transects allowed to extend within ten <br />feet of reclaimed area boundaries to minimize impacts from "edge effect." <br />For statistical purposes, each cover transect (comprising 50 data points) served as a sample <br />unit. Data points recorded the first vertical "hit" on vegetation (above or below the instrument), <br />soil (bare ground), rock, or organic litter. Cover data were recorded and reported by individual <br />plant species. <br />2.3 SAMPLE NUMBERS/SAMPLE ADEQUACY <br />For the purposes of this study, total live vegetation cover sampling was undertaken to sample <br />adequacy with a minimum of fifteen (15) samples. <br />Parameter sample adequacy testing occurred at the one-sided 90% confidence level. <br />Comparisons between sample mean parameter values and the revegetation success standard <br />assume that the sample mean value accurately represents the population mean in all cases. <br />The following formula was used for sample adequacy calculations: <br />nmin <br />(t)2 (s)2 <br />= <br />(d Xbar)2 <br />where: nmin = minimum sample size <br />s = sample standard deviation <br />t = the Student's t distribution value at the 90% level (one-sided) <br />d = percent acceptable deviation from the mean (10%) <br />Xbar = sample mean <br />Oxbow Mining, LLC Elk Creek Mine Page 4 <br />2020 Phase III Bond Release Pre-5MCRA Vegetation Report <br />