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Semi-Annual Subsidence Monitoring Reyort <br />Period: July I, 1997 -December 31, 1997 <br />Page 2 <br />1.2 Newlin Creek Point <br />Survey data for the Newlin Creek point show a change of 0.92 feet of subsidence through the <br />forth quarter of 1997. Similar to the survey data for the ranch structures, above, it is not likely <br />that any subsidence has occurred at this monument. No mining operations have occurred in the <br />vicinity of this survey point since 1982 to cause additional subsidence. <br />1.3 Florence Water Line <br />Survey data obtained at the eight monuments along the Florence Water Line indicate minor <br />subsidence occurring only at Monuments D, E, and I during the reporting period. The amount of <br />measured subsidence at these monuments ranged from 0.12 to 0.23 feet. Minimal vertical change <br />was measured at the remaining six monitoring locations. No recent mining has been done in the <br />vicinity of monitoring locations that would cause additional subsidence. <br />The maximum measured subsidence along the water line occurs at Monument I, with a current <br />deflection of 3.69 feet as compared to the original survey. This value is within the permit <br />maximum expected and worst-case expected subsidence values of 2.79 and 4.36 feet respectively. <br />No new surface cracks or other subsidence related features were observed during the reporting <br />period. Previous surface cracks, as documented in the semi-annual reports, have healed and not <br />reappeared. <br />Subsidence monitoring of structures indicates that subsidence is occurring only at certain locations <br />along the water line, and that the magnitude of displacement is within predicted values. Only <br />minor additional subsidence is expected to occur at the structure monitoring locations. <br />