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The average orientation of the F-3 data collected for the 2005 report is <br />approximately parallel with the southeast wall, with an average dip that is only a <br />few degrees shallower than the southeast wall (45°), but the average orientation <br />of the 2006 data is somewhat oblique to the wall. <br />In previous annual reports, toppling about discontinuity plane P-1 also existed as <br />another mechanism of potential block movement for the southeast wall. <br />However, as shown on Figure 15 both the slope face and discontinuity plane P-1 <br />no longer share the same basic strike. A review of photographs during previous <br />annual studies does indicate that there are some continuous surfaces that form <br />the face of the south wall. However, none of these surfaces appear to be <br />discontinuity plane P-1, which has a dip of 72° to the south. <br />The foliation F-1 also strikes in the same general direction as both the southeast <br />slope face and discontinuity plane P-1, although at an overall shallower dip. It is <br />believed that the foliation will prevent large failure surfaces from developing along <br />the south wall simply by creating a systematic set of blocks that cannot dislodge. <br />This has been observed in the rock exposures on the south wall that have a <br />broken reverse-stepped orientation, and that also expose the undersides of the <br />foliation surfaces. <br />-23- <br />