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<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 />I 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 <br />along the south wall simply by creating a systematic set of blocks that cannot <br />dislodge. This has been observed in the rock exposures on the south wall that <br />have a broken reverse-stepped orientation, and that also expose the undersides <br />of the foliation surfaces. <br /> <br /> <br /> <br />' -23-