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INTEROFFICE MEMORANDUM <br />TO: ROB ZUBER <br />FROM: JASON MUSICKW - <br />SUBJECT: C1981-010 TRAPPER MINE SL-11 BOND RELEASE INSPECTIONBACKFILLING AND GRADING GPS <br />INSPECTION <br />DATE: 04/22/2010 <br />In order to determine compliance with Trapper's backfilling and grading to meet the approximate original contour <br />for SL-11, 20 locations were derived on contour lines utilizing Trapper's SL-11 Bond Release Map Sheets 1, 2 and <br />3. Points were placed at various contour elevations in ArcGIS and those points were then downloaded into a <br />Trimble GeoXT. During the bond release inspection, the points were navigated to using the data in the Trimble <br />and another point was collected to determine the elevation as compared to elevation information provided in the <br />SL 11 Bond Release application. The points collected at the site were downloaded from the Trimble into <br />Pathfinder office and converted into a point shapefile to utilize in ArcGIS. The points collected were compared <br />with the random points based on elevation. <br />Elevation data, using the Trimble GeoXT is not exact. The Geoid used in the Trimble GeoXT is DMA 10X10 <br />Global, which is a global elevation Geoid and not as accurate as a localized Geoid. For this reason a point was <br />collected on the Trapper Mine office roof base station to determine a correction factor for the elevation collected in <br />the Trimble GeoXT. The elevation at the base station was 6512' compared to 6527' on the Trimble, which provide <br />a correction of +14 feet. The main purpose of the elevation collection was to determine if the elevation data <br />showed any anomalies such as drastic elevation changes or fluctuations in elevation. All elevation points were <br />found to be between 13' and 19' above the elevations of the approved AOC. Given the correction factor of +14' at <br />the Trapper Mine Base Station the difference in elevation is acceptable. Trapper's backfilling and grading was <br />consistent with the contours submitted with the SL-11 application and the approved AOC. <br />Sts ' ?:. Y ` -1!t _ ? ? <br /> <br /> <br />t -ail - :-y <br /> <br /> <br /> <br /> <br />?.y <br /> <br /> <br /> 141 <br /> <br /> <br />Elevation Points F-AB-08 and Z-AB-08 <br />j ) itd vn + nN <br />' 'r'• . ;7 is - `: , , <br />1 4 <br />??:1 IE War '- l <br />Elevation Points Z-AB-08