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' points via optical survey. <br /> Twenty six post-repair surface survey monuments (designated 2001 through <br /> ' 2026) were established to monitor the performance of the 1996 Central Quarry <br /> East Highwall repair. Ten of the 26 points were lost in 1996 due to damage by <br /> mining equipment or reclamation grading; these were nos. 2007, 2008, and 2012 <br /> ' through 2019. During 1997, two additional points (2002 and 2006) were lost. <br /> Survey data for the remaining points taken in March 1.997, May 1997 and March <br /> 1998 document the performance of the repair during 1997. A discussion of <br /> ' these data are provided below, and the data and a map of the survey point <br /> locations is included as Appendix B. <br /> 4.3 Central Quarry Floor <br /> A 40 ft deep slot below the general Central Quarry floor at approximately El. 6.490 ft <br /> ' was removed during 1997 down to approximately El. 6,450 ft. Relatively high specific <br /> gravity rock due to localized iron mineralization was encountered in this mined area. <br /> This "heavy" mineralization presented some operational complications relative to <br /> excavation, crushing and product specifications, but did not pose any stability concerns. <br /> CAMAS collected some geotechnical data related to this localized occurrence to make <br /> quality control adjustments for aggregate product specifications. In general, variations in <br /> mineralogy and specific gravity of rock from this horizon were tested and evaluated. <br /> Mineralogy investigations consisted of performing petrographic analyses of selected <br /> samples. Specific gravity tests were also run at the on-site quality control laboratory. <br /> These data were used for product purposes and are not considered to be relevant to <br /> stability issues addressed in this Geotechnical Addendum. <br /> ' 7 G:\PROJECTS\20200\00'\97AN NR Pr.W PP <br />