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Energy Fuels Coal, Inc. Southfield Mine SEMI-ANNUAL SUBSIDENCE MONTCORING REPORT Period: ]anuary 1, 1998 -June 30, 1998 Introduction RECEIVED JUN 111999 Division of Minerals 8 Geobgr The semi-annual subsidence monitoring report compares field survey monitoring data to permit predictions for inventoried structures. Summarized survey data are shown in attached Table 1, Semi-Annual Subsidence Monitoring Data. These data show location and orientation of monuments and structures for the reporting period. Additionally, original survey data for all subsidence monitoring locations are shown on attached Table 2, Original Subsidence Monument Data. Field surveys aze conducted on only the structures (including the Newlin Creek point) shown on Table 2. EFCI will survey the South Grid monument network after mining operations have ceased as approved in the permit. EFCI performed two quarterly subsidence surveys of the structures shown on Table 1 during the reporting period. The surveys were done using conventional EDM equipment for both horizontal and vertical wntrol. Discussion of the subsidence data, and any current visual observation information, is shown below. Discussion 1. Structures Structures monitored quarterly for subsidence include the Thompson Ranch buildings, the Florence City water line, and the Newlin Creek point. Summarized survey data for these structures are shown on acoompanyiag Table 1, Semi-Annual Subsidence Monitoring Data Summary. Location of the structures and monuments with respect to the Mine layout aze shown on Map 17 in the permit application. Discussion of survey monitoring data compared to permit predictions for inventoried structures follows below. 1.1 Thompson Ranch Structures Survey data for the 2nd quarter 1998 indicate that no subsidence has occurred in the azea of the monitored ranch structures relative to the original data. Data included in the previous semi-annual reported showed subsidence of the structures ranging from 0.70 to 0.78 feet. Current data confirm that these data were exaggerated probably as a result of survey error. No mining has occurred below the ranch area that would cause subsidence. Survey data for the south ranch house, comparing 1st and 2nd quarter survey data, show a horizontal change of 27.25 feet. A review of the survey notes indicates that this large value was caused by a field surveying error. Survey data from the 2nd quarter survey of the south house, compared to original survey data, shows a horizontal change of 0.11 feet. This is consistent with previous survey reporting periods.