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-B-BA <br />water consultants <br />BISHOP-BROGDEN ASSOCIATES, INC. <br />September 19, 2013 <br />George Patterson <br />Energy Fuels Coal, Inc. <br />PO Box 459 <br />Florence, CO 81226 <br />RE: Response to Preliminary Adequacy Concerns for Technical Revision No. 40 <br />Dear George: <br />Christopher J. Sanchez <br />Jeffrey A. Clark <br />Michael A. Sayler <br />Daniel O. Niemela <br />Charles E. Stanzione <br />Jonathan D. George <br />We are writing to address the informational requests stated in the letter addressed to you from Janet <br />Binns dated August 29, 2013 regarding preliminary adequacy concerns associated with Technical <br />Revision No. 40 (TR -40) for the Southfield Mine that was provided for our review. Specifically, we <br />are writing to provide additional information regarding the evaluation prepared by our office dated <br />July 19, 2013 to support the calculation of mine volumes above and below elevations of interest, the <br />methodology used to estimate the mine inflow of 14 acre -feet per year (af /yr) and the conceptual <br />models used to determine the timing of mine refilling. <br />Mine Volume Calculations <br />As indicated in our July 19, 2013 evaluation letter, we relied on the Southfield Permanent Mine <br />Closure Map dated 2001 to identify areas and volumes within the mine above and below elevations <br />of interest. We also relied on a previous estimation of the total mine volume presented on page <br />2.05.6 -32 of the approved permit document. That calculation was based on a total mine area of <br />1,370 acres, an average mine height of 7 feet and an average recovery of 60 percent of the material <br />in the mine for a total mine area of approximately 5,700 acre -feet. <br />The closure map was used by our office to determine a total scaled area for the mine, scaled pillared <br />areas below elevations of interest and scaled non - pillared areas below elevations of interest based on <br />information included on the map. With the scaled pillared and non - pillared areas determined for <br />each elevation of interest for each conceptual model and the total scaled area of the mine, we were <br />able to determine what percentage of the total mine area was below each elevation of interest that <br />would fill before reaching that elevation. <br />Pillaring within the mine was accounted for by weighting pillared areas more heavily to account for <br />1 100' <br />www bbawater.com <br />