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,:. <br />Energy Fuels Coal, Inc <br />Southfield Mine <br />l~II ~I~~IIII~~~~~~I~ <br />sss .. <br />APR 3 0 2001 <br />Division of Minerals & Geo <br />a9Y <br />SEMI-ANNUAL SUBSIDENCE MONTI'ORING REPORT <br />Period: July 1, 2000 -December 31, 2000 <br />Introduction <br />The semi-annual subsidence monitoring report compares field survey monitoring data to permit <br />predictions for inventoried structures. Summarized survey data are shown in attached Table 1, <br />Semi-Annual Subsidence Monitoring Data. These data show location and orientation of <br />monuments and structures for the reporting period. Additionally, the original survey data and <br />current quarterly survey data for all subsidence monitoring locations are shown on attached Table <br />2, Current Report Data. <br />Field surveys are conducted on the structure monuments shown on Table 1. EFCI will survey the <br />South Grid monument network after mining operations have permanently ceased, as approved in <br />the permit. <br />EFCI performed two quarterly subsidence surveys of the structures shown on Table 1 during the <br />reporting period. The surveys were completed using differential GPS equipment for both <br />horizontal and vertical control. Discussion of the subsidence data, and any current visual <br />observation information, is shown below. <br />1. Structures <br />Structures monitored quarterly for subsidence include the Thompson Ranch buildings, the <br />Florence City water line, and the Newlin Creek point. Summarized survey data for these <br />structures aze shown on accompanying Table 1, Semi-Annual Subsidence Monitoring Data <br />Summary. Location of the structures and monuments with respect to the Mine layout are shown <br />on Map 17 in the permit application. Discussion of survey monitoring data compared to permit <br />predictions for inventoried structures follows below. <br />1.1 Thompson Ranch Structures <br />Survey data for the reporting period indicate vertical changes, compared to original data, ranging <br />from 0.0 to 0.04 feet. No subsidence is expected since mining has not occurred below the ranch <br />azea that would cause subsidence. In addition, there are no physical indications of subsidence on <br />or near the monitored structures. <br />