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obvious errors from a 'Rust" in the survey. Therefore, calculated means and <br /> standard deviations for magnitude of movement and rates of movement are distorted <br /> in some cases and will eventually require correction in order to accurately <br /> reflect the character of the movement observed. <br /> Ignoring these data errors, it is apparent that many of the monuments in the <br /> ridge top environment and the steeply sloping environment are undergoing a <br /> relatively constant background level of vertical displacement caused by surface <br /> creep and incipient landslide movement. Where relatively minor amounts of <br /> subsidence are occurring, this background level of movement may mask the presence <br /> of the subisdenoe movements. <br /> There are two clear exceptions to this where it is relatively obvious that <br /> the movements of the monuments are subsidence related. This is the case of <br /> monument U21 and U22 (see Figure 12 ) . The plots for these monuments show sharp <br /> deviations from this background level of movement that correlate directly in time <br /> with the mining activity in the panels below them. Although somewhat more <br /> subtle, we also believe that monuments for sites U4 and UP2 also depict <br /> subsidence (see Figure 13 ) . A couparison of estimated versus actual subsidence <br /> will be made for these four monuments in section 4.3. <br /> 4.0 SUBSIDENCE CAT CUTATXC S <br /> 4.1 Zone Area Method <br /> The predictive method selected for use on this site is the zone area method <br /> based primarily on the work of Marr, 1975. The zone area method is an influence <br /> function technique. The influence of the extracted area on any given point on <br /> the surface is determined by the construction of a series of circular zones or <br />