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<br /> <br /> <br /> <br /> <br />Permit Number C1981028 Prepared by: R. Reilley, MS, GISP <br />SL9 8 <br /> <br /> <br /> <br /> <br /> <br />Illustration 1 (left): Screen capture from the UNAVCO site <br />showing the method of converting GPS measurement of <br />elevation to height above mean sea level. <br /> <br />As illustrated in the above methodology, many <br />variables affect the precision of field-collected <br />elevations measured with a handheld GPS unit. Of <br />the points collected in the field, 20 were utilized <br />for elevation validation. The average GPS <br />positional error for these points was 5.28 ft. <br />However, as demonstrated by the data collected <br />and illustrated below, the difference in field <br />collected elevation appears generally consistent <br />throughout the site and adequately corroborates <br />CEC’s approved post mining topography (PMT). <br /> <br />Using Microsoft Excel® (Table 1), the Division <br />charted the elevations for the both the SL8 <br />map and the PMT map, and DRMS’s on-the- <br />ground measured elevations, converting the field <br />data (GNSS_Alt) to elevation above mean sea level and created cross-sections for each transect and its <br />associated reclamation parcel for comparison. This underlying data for the topographic analysis is <br />presented in Table II Table 1 at the end of this document. The illustrations below show transect locations, <br />field collected points in relationship to the SL8 Map, and transect cross sections exhibiting the elevation <br />differences between the two maps and field collected information. <br /> <br />Phase I bond release was requested for areas 33 and 34 comprising 12.46 and 6.93 acres respectively, <br />for a total of 19.39 acres. The bond release area is depicted in Map 1 above. The inspection began at <br />the east end of area 33 where three transects were walked and elevations recorded with the Bad Elf <br />GNSS recording device. Next, area 34 was similarly inspected by recording points in two transects <br />as shown in the maps below. Figures one through five below show elevation cross sections as per <br />CEC maps and Division field collected data.