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Martin Marietta Materials <br />Spec -Agg 2014 Annual Report <br />The northern faces of the main pit were modified after planar failure along foliation planes in 1998 and <br />1999. These slopes did not appear to show signs of additional movement during the site visits for this <br />study (Photo 4). As previously reported, the overall effective angle of the last three benches of the north <br />pit walls has been modified to an angle of 35 °, which is consistent with the 2003 Lachel geotechnical <br />evaluation (L&A, 2003). The failure surfaces (i.e., the surfaces along which movement has occurred) <br />remain at a "residual strength" and therefore are less resistant to additional loading. Although the slope <br />configuration is currently stable, the failure mechanism could potentially be reactivated, resulting in <br />movement of additional material. The northern wall slopes should continue to be visually monitored for <br />indications of instability. <br />March 31, 2014 Page 7 Lachel & Associates, Inc. <br />Project 13364013 00 02014 All Rights Reserved <br />