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Martin Marietta Materials <br />Spec -Agg 2014 Annual Report <br />7.0 CONCLUSIONS AND RECOMMENDATIONS <br />The results of the structural geologic evaluation and kinematic rock slope stability assessment for the <br />Spec -Agg Quarry does not indicate any immediate concerns with respect to large -scale instabilities in the <br />current final quarry wall faces based on our field observations and current rock mass assumptions. The <br />stability of the slopes is enhanced by the absence of significant hydrostatic pressure, by current mining <br />procedures and by the current reclamation process being implemented by Martin Marietta at the site. <br />While large -scale failures are not anticipated, the slope will continue to shed rocks over time as a result of <br />small -scale failures, particularly in near - vertical temporary bench faces. <br />For the 2014 annual report, kinematic analyses are based on discontinuity measurements derived <br />principally from data collected from the existing growing dataset supplement with data collected during <br />the November 2013 and March 2014 site visits. The results of these analyses are not intended to <br />supersede results of analyses performed for prior years that were based on representative discontinuity <br />orientations generated from the entire dataset of measurements. Rather the analyses presented herein <br />are meant to compliment previous years' analyses and enable monitoring of possible new trends in the <br />data that could result in previously unconsidered failure modes. <br />The collected data for this evaluation was complimentary to and were consistent with past analyses. It is <br />noted that the results for the current analysis did not change the pole or the resultant concentration center <br />for any of the delineated joint sets significantly from any of the recent years' results. In general, the data <br />collected during the November 2013 and March 2014 site visits correspond reasonably well with <br />representative discontinuity orientations used in previous reports; however, we noted some differences <br />which we applied to our kinematic analyses for the 2014 annual report. <br />The kinematic analysis for East Wall 1, Northeast Walls 2 and 3, Northwest Wall, West Walls 1,2 and 3, <br />and Southeast Wall each indicate the possibility for wedge failures to occur. Additionally, the analysis for <br />Northeast Walls 1 and 3 shows the potential for planar failure. The walls of the quarry in these areas <br />should continue to be monitored closely as mining continues to assess the potential for the indicated <br />failure modes to contribute to large -scale slope instability of a final mine highwall based on the continuity, <br />regularity and variation in orientations of the discontinuities involved. <br />We also recommend that known faults are tracked and observed in new exposures to confirm orientation <br />and character for supplemental stability analysis, as needed. We expect the southern fault identified by <br />Gable (1968) and in previous years site visits (Figure 3) may be exposed in other locations as <br />excavations continue in the Southern Expansion Area. Additionally, the unmapped fault generally located <br />in the central portion of the quarry may be exposed for mapping in the future. In addition, as <br />recommended in the previous reports, evaluations will be conducted during future investigations to <br />assess whether or not any of the foliation sets (F -1 through F -3) are caused due to localized faulting that <br />may have resulted in "structural regions" that have created areas in which the varying orientation of the <br />foliation planes occur. These questions will continue to be addressed as more data are collected. <br />As documented in the past, localized raveling, especially along the south walls is likely to continue. <br />Continuation of the safety- minded policies already in place, which limit the height of the exposed highwall <br />as well as the reclamation of exposed highwalls as soon as possible following blasting and rock haulage, <br />will aid in minimizing the potential for instabilities to occur. <br />March 31, 2014 Page 16 Lachel & Associates, Inc. <br />Project 13364013 00 02014 All Rights Reserved <br />