Laserfiche WebLink
Martin Marietta Materials <br />Spec -Agg Project <br />4.0 FIELD OBSERVATIONS <br />In addition to the structural geology data collected, the following field observations were also used to <br />evaluate the current quarry conditions: <br />1) Significant mining progress has occurred in the main pit of the quarry since the previous annual report <br />was prepared in February 2011 (L &A, 2011). In the main pit, the base elevation of 6,242 feet has been <br />deepened around the area of the new sump by approximately 15 feet to an estimated elevation of <br />6,227 feet (Photo 5). This sump appears to currently be the only one used and has been expanded <br />since the previous investigation. <br />2) In the southern expansion area, the eighth bench is being reclaimed as the ninth bench is being <br />excavated (Photo 5). The ninth bench is being mined starting from the eastern side of this level and <br />working to the west. <br />3) The quarry walls appeared to be relatively dry; and noticeably absent is any major seepage in the <br />southwest corner of the main pit, which had been documented in prior reports as having occasional <br />seeps visible. <br />4) As noted in previous annual reports, a minor east -west striking unnamed fault has been mapped in the <br />northwest corner of the main pit. This fault is also visible in the east wall of the main pit (Figure 3) and <br />was re- exposed on the west and northwest walls during a sump excavation although it is no longer <br />visible. The rock within this fault zone is broken and blocky, with parallel fracturing, iron - stained <br />surfaces and alterations in the rock. <br />Field measurements taken in 2008 and 2009 indicate an apparent strike of 080 -090° and dip of 75- <br />80°S for the fault. The apparent width of the fault zone varies in the main pit between approximately <br />20 and 50 feet. Excavation of the north and west benches will continue to intercept the fault, and the <br />length of the fault exposure in the walls will increase as mining progresses. Based on the average dip <br />of the fault, at approximately an elevation of 6,260 feet, the fault may be exposed across the floor of <br />the main pit. Currently this area is being used as a haul road at this approximate elevation, so <br />monitoring of this interface will facilitate a better understanding of how the slope will behave. <br />5) The fault in the southern expansion area was exposed again during the current excavation year. <br />Notations regarding the mapped orientation of the fault are listed on Figure 3, with an average strike <br />320 -345° and dip of 70 -85 °SW (Photo 2). <br />6) The south facing temporary wall in the main pit is noted by the lower quality of rock exposed during <br />recent blasting efforts requiring the mine to expand the width of the benches to avoid loose material <br />falling to the actively mined floor. Portions of the temporary walls exposed appeared iron stained and <br />were blockier (Photo 6) between elevations 6,265 and 6,240. <br />7) Minor raveling conditions resulting from rock fragmentation during blasting and subsequent <br />freeze /thaw conditions exist along each wall in the quarry, but appear more prevalent along the south <br />wall possibly due to the north facing exposure. <br />February 13, 2012 <br />Page 6 Lachel & Associates, Inc. <br />Project 11361017.00 ©2012 All Rights Reserved <br />