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ENERGY FUELS COAL, INC. SOUTHFIELD MINE SEMI-ANNUAL SUBSIDENCE MONITORING REPORT (NOVEMBER, 1989 THROUGH APRIL, 1990) INTRODUCTION This report presents summarized data from quarterly subsidence surveys for the above reporting period. Enclosed is tabulated survey monument and structure location orientation data and cross sections of the high-resolution grid. STRUCTURE SURVEYS Field survey data from tiie three (3) monitored structures are summarized on tables 2 and 3. The data indicated that no subsidence is occuring at tl~e three Thompson Ranch structures or at the nearby Newlin Creek point. This information is consistent with previous semi-annual reports. Tlie data for the Florence Water Line Monuments indicate only minor subsidence occuring at monument 'E', and no change at the other six monuments. SUBSIDENCE GRID SURVEYS Field survey data from the 23 monuments in the high-resolution grid are shown on Table 1, and also in cross-sections on Figures 1 and 2. Reviewing the data indicates that only minor additional subsidence is occuring, in agreement with previous surveys. The monuments which have shown the greatest vertical change, such as monuments 4 and 15, continue to exhibit the largest relative movement. The vertical change is, however, very gradual and consistent with previous survey periods. The information continues to indicate that [he minor changes are a result of consolidation of the caved material above the mine workings. CONCLUSIONS Southfield's subsidence monitoring program continues to monitor orientation and displacement changes in structures and monuments. Data collected through this reporting period indicate subsidence magnitude less than that predicted in the permit application. No material damage to structures has been observed consistent with the minor displacements measured by surveys. Additional subsidence and subsidence effects are expected to be minor as predicted in the permit application.