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, energy fuels coal, inc. wutbllNtl mlrw • pwt oMka boa Mp • fbrenoe, wlondo 1172! • (71pJ 7B~-0.'4p5 January 8, 1996 Mr. David Berry Division of Minerals and Geology 1313 Sherman Street, Room 215 Denver, Colorado 80203 III IIIIIIIIIIIIIIII 999 1~ 1, RGrt=1~IF JAN 2 2 199& Division of Minerals ~ Geology RE: Transmittal of Semi-Annual Subsidence Monitoring Report: Period 5/1/95 to 10/31/95, and Request for a Minor Revision (MR-28): Subsidence Monitoring Southfield Mine, Permit No. C-81-014 Deaz David: Enclosed with this transmittal letter is one copy of Energy Fuels Coal, Inc (EFCI) Subsidence Monitoring Report for the semi-annual period ending October 31, 1995. Additionally, EFCI encloses revised permit materials to support a request for a minor revision of Section 2.05.6, Subsidence Survey, Subsidence Monitoring, and Subsidence Control Plan. This minor revision request addresses questions from DMG's review of previous semi-annual monitoring reports, and monitoring requirements of the high-resolution monument grid. Specifically, the revision will state the due date of future semi-annual reports, and set the monitoring periods to coincide with calendaz quarters. Since EFCI has completed survey monitoring of all subsidence points through the fourth quarter of 1995 (refer to enclosed report), the next semi-annual period will include the first and second calendar quarters of 1996. The revised semi-annual periods and submittal dates aze included in attached permit pages. The minor revision also proposes to eliminate the high-resolution monument grid from the survey monitoring program. Incremental subsidence of all monuments has decreased rapidly beginning in 1986, and has almost ceased to occur since 1992. Evidence of this is shown on attached Table 1, High-Resolution Grid Survey Data, and in graphic format on attached Figure 22, Subsidence History/ Maximum Subsidence -High-Resolution Grid. These data show the correlation between subsidence and mining history. Retreat mining of the panel (2 South-'A' Panel) directly under the monument grid occurred from April 1983 through June 1983. Subsequent retreat mining of the adjacent panel (2 South-'B' Panel), underlying Monuments ]0 through 15, occurred from June 1985 thorough August 1985. These dates mark the cessation of mining in the areas potentially impacting the high-resolution grid.