2014-05-02_REPORT - M1974004

• Permit No: M1974004
• IBM Index Class Name: REPORT
• Doc Date: 5/2/2014
• Doc Name: Stability analysis of spec agg quarry
• From: Martin Marietta Materials
• To: DRMS
• Email Name: PSH
• Media Type: D
• Archive: No

Martin Marietta Materials
Spec -Agg 2014 Annual Report
Our analysis indicates that potential planar and wedge failures may form in individual benches along the
northern walls with near vertical faces during the temporary conditions prior to reclamation.
6.4.4 West Walls
For the 2014 annual report, we analyzed three west wall orientations based on the locations shown in
Figure 2 and Table 2: West Walls 1 through 3. The wall locations and orientations correspond to the
same wall locations and orientations analyzed in previous annual reports.
The stereonet plot for West Wall 1, adjacent to the Main Pit area, shows one discontinuity intersection
that falls within the failure envelope, suggesting that wedge failure is kinematically possible for this slope
orientation (Figure 11). The intersecting sets that may result in wedge failure include joint P -1 and joint P-
6. Planar failure is not indicated in the stereonet plot for West Wall (Figure 11). Our analysis indicates
that potential planar failure may form in individual benches along the West Wall 1 with near vertical faces
during the temporary conditions prior to reclamation.
The stereonet plot for West Wall 2, adjacent to the Southern Expansion Area, shows two discontinuity
intersections that fall within the failure envelope, suggesting that wedge failure is kinematically possible
for this slope orientation (Figure 12). The intersecting sets that may result in wedge failure include joint
sets P -1 and P -6, and joint sets P -2 and P -7. Based on the 2014 data set, joint P -7 has weak signatures
represented by relatively few measured orientations representing these features (Figure 6). Planar failure
is not indicated in the stereonet plot for West Wall 2 (Figure 12).
The stereonet plot for West Wall 3 shows one discontinuity intersection that falls within the critical zone,
suggesting that wedge failure is kinematically possible for this slope orientation (Figure 12). The
intersecting sets that may result in wedge failure includes joint sets P -1 and P -6. The signature of P -1
appears to be relatively weak in the Southern Expansion Area (Figure 6). The development and size of
wedge failures will be controlled by the variability and limited lateral extent of the discontinuities. As
excavation proceeds for West Wall 3, additional measurements are needed to refine the representative
discontinuity orientations of these joint and foliation sets in this area to evaluate their potential contribute
to large -scale slope failure modes.
6.4.5 Southern Walls
For the 2014 annual report, we analyzed four southern wall orientations based on the locations shown in
Figure 2 and Table 2: Southwest Walls 1 and 2, the South Wall, and the Southeast Wall. The wall
locations and orientations for the Southwest and Southeast Walls correspond to the same wall locations
and orientations analyzed in previous annual reports (Figure 2).
The stereonet plots for Southwest Walls 1, 2, and the South Wall do not show indications of potential
planar or wedge failure modes based on the 2014 discontinuity measurements (Figures 13 and 14).
The stereonet plot for Southeast Wall shows one discontinuity intersection that falls within the critical
zone, suggesting that wedge failure is kinematically possible for this slope orientation (Figure 15). The
intersecting sets that may result in wedge failure includes joint sets P -3 and P-6. The signatures of P -3
and P -3 appears to be relatively strong in the Southern Expansion Area (Figure 6) based on the 2013-
March 31, 2014 Page 14 Lachel & Associates, Inc.
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