Laserfiche WebLink
Southfield Mine Semi-Annual Subsidence Monitoring Report <br />Period: July 1 through December 31, 2001 <br />Page 2 <br />1.2 Newlin Creek Point <br />Survey data for the Newlin Creek point show a change of -0.29 feet of subsidence, compared to <br />the original survey data, through the 4th quarter of 2001. Similar to the survey data for the ranch <br />structures, it is not likely that any subsidence has occurred at this monument. No mining <br />operations have occurred in the vicinity of this survey point since 1982 to cause additional <br />subsidence. <br />1.3 Florence Water Line <br />Survey data obtained at the nine monuments along the Florence Water Line indicate minor or no <br />additional subsidence occurring in the area of the water line during the reporting period. The <br />amount of measured subsidence at these monuments, as compared to original data, ranged from <br />-0.07 to -3.24 feet. No recent mining has been done in the vicinity of monitoring locations that <br />would cause additional subsidence. <br />The maximum measured subsidence along the water line occurs at Monument G, with a current <br />deftection of -3.25 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 />_ _ ._ Visual Observations <br />No cracks or other subsidence related features were observed during the reporting period. <br />Previously observed surface cracks, as seen primarily on County Road 15, have healed and not <br />reappeared. <br />Conclusions <br />Subsidence monitoring of structures indicates that only minor subsidence is occurring at locations <br />along the Florence water line, and that the magnitude of displacement is within predicted values. <br />Only minor additional subsidence is expected to occur at the structure monitoring locations. <br />