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Martin Marietta Materials <br />Spec -Agg 2013 Annual Report <br />Minor raveling conditions resulting from rock fragmentation during blasting and subsequent freeze /thaw <br />conditions exist along each wall in the quarry, but appear more prevalent along the south wall possibly due to <br />the north facing exposure. <br />The quarry walls observed during the site visits performed for this annual report appeared to be relatively <br />dry. No major seepage was observed. During our March 2013 site visit, we observed standing water in the <br />sump of the main pit; however, the sump pump was not operating. The main pit floor was wet and muddy. <br />Reportedly, the sump installed in the main pit in 2011 had been pumping at approximately 81,000 gallons per <br />day to keep the main pit dry. <br />The northern faces of the main pit were modified after planar failure along foliation planes in 1998 and 1999. <br />These slopes did not appear to show signs of additional movement during the site visits for this study. As <br />previously reported, the overall effective angle of the last three benches of the north pit walls has been <br />modified to an angle of 35 °, which is consistent with the 2003 Lachel geotechnical evaluation (L &A, 2003). <br />The failure surfaces (i.e., the surfaces along which movement has occurred) remain at a "residual strength" <br />and therefore are less resistant to additional loading. Although the slope configuration is currently stable, the <br />failure mechanism could potentially be reactivated, resulting in movement of additional material. The <br />northern wall slopes should continue to be visually monitored for indications of instability. <br />April 22, 2013 Page 8 Lachel & Associates, Inc. <br />Project 12361005.00 ©2013 All Rights Reserved <br />