2013-05-03_GENERAL DOCUMENTS - M1974004

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Martin Marietta Materials Spec -Agg 2013 Annual Report 5.0 FIELD OBSERVATIONS Field observations for the 2013 annual report consisted of rock structure mapping and collecting information regarding areas of visible large -scale instability, seepage, and mining activity. Observations for the current annual report were made during two site visits, which took place in October 2012 and March 2013. We performed rock structure mapping during the two site visits to collect representative discontinuity measurements from recently mined rock exposures in the Main Pit and Southern Expansion areas (Figure 2; Photos 1 through 4). Orientation measurements (i.e., dip /dip direction) of joints, foliation, and faults were taken from the faces of advancing benches. A geological compass was used to obtain discontinuity measurements both indirectly by sighting along the discontinuity surfaces and, where deemed safe, by direct measurement on the discontinuity surfaces. A handheld GPS was used to record the location of data collection points (Figure 2). A total of 61 discontinuity measurements were collected at nine data collection points, and were added to the measurements from previous years. When combined with data collected from previous annual reports (1997 -2002, 2004 -2011) and with borehole geophysical data collected during the 2003 geotechnical investigation, a total of 3,169 discontinuity orientation measurements have been obtained over the past 16 years. Figure 5 shows the 61 discontinuity orientation measurements collected for this annual report overlain on a contour stereonet plot of the entire Spec -Agg structural dataset. During our March 2013 site visit, we observed a newly exposed fault along the northern wall of the Main Pit at station 13 -01 (Figure 3 and Photo 5). The fault is oriented approximately north- south, with dip /dip direction of 59/089. A second, north -south oriented fault was also observed above the access road and just northeast of the first exposure at station 13 -08 (Figure 3). The orientation of this fault was measured to be 64/078 (dip /dip direction). The two fault exposures are separated by the east -west oriented fault of Gable (1968), indicating that they may represent the same fault that has been offset by movement along the east - west oriented fault. We collected an additional orientation measurement (90/349) of this east -west fault during our March 2013 site visit above the access road at station 13 -08. Previous annual reports reported observation of a minor, east -west striking unnamed fault in the northwest corner of the main pit. The fault zone was reported to consist of weathered, broken and blocky rock, with parallel fracturing, and iron - stained surfaces. This fault was not observed during our 2012 -2013 site visits. Field measurements taken in 2008 and 2009 indicate an orientation of 350 - 000/75 -80 (dip /dip direction) for the fault. Reportedly, the apparent width of the fault zone varies in the main pit between approximately 20 ft and 50 ft. The fault in the Southern Expansion area was observed during our October 2012 site visit. Notations regarding the mapped orientation of the fault are listed on Figure 3, with an average dip /dip direction of 78/152. The fault orientation measurements for this annual report are presented with previous fault measurements and differentiated by the fault feature they represent in Figure 4. April 22, 2013 Page 7 Lachel & Associates, Inc. Protect 12361005.00 ©2013 All Rights Reserved