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<br />MINED LAND RECLAMATION DIVISION <br />Department of Natural Resources <br />7313 Sherman SI.. Room 215 <br />Denver, CG 80203 <br />303 6663567 <br />Rgx:303 832-Bt06 <br />January 9, 1992 <br />Mr. Allen 5. Weaver <br />Energy Fuels Coal, Inc. <br />P.0. Box 449 <br />Florence, Colorado 81226 <br />SUBJECT: NOY C-92-O1, Southfield Mine, File No. C-81-014 <br />Dear Mr. Weaver: <br />OF' ~~/0 <br />'~F'i= R> <br />s. '" g <br />'.\:~ <br />~ rb ]6 <br />Roy Romer. <br />Governor <br />Fretl R. Barra. <br />Div~s~on Dvector <br />The Division has decided to write an additional violation as a consequence <br />of the December 17-19, 1991 inspection. Despite the appearance of visual <br />stability of the coal processing waste pile, it is apparent that the pile is <br />not being constructed in accordance with the plan; specifically a 3:1 <br />(coarse:fine) mixture is not being utilized, and positive drainage of water <br />off the crest of the fill is not being maintained. <br />The Division requested a plan for evaluating waste pile stability <br />September 30, 1991, following review of waste pile inspection reports. ACZ <br />came forward with a plan on November 1, 1991. The ACZ plan proposed to <br />utilize 1988 data from a Geowest study. The Division approved the plan in <br />early December, asking only that the 1988 data be included in the submittal. <br />As a result of the December 17-19, inspection, it is now apparent the refined <br />material is being produced in a 3:2 (coarse to fine) proportion, relative from <br />the 3:1 (coarse:fine) proportion anticipated in your original approved <br />design. Further, refuse is being placed in the pile in alternating coarse and <br />fine layers, rather than mixed to form a composite material, as originally <br />anticipated in the approved plan. The Division is concerned that this <br />situation may have deleterious implications for stability of the structure. <br />The Division has had an opportunity to review the 1988 Geowest study. The <br />field data acquired from this study was proposed to be utilized as the basis <br />of the ACZ stability study. The Division has reservations that the shear <br />test analysis values are not representative of fine grained materials. The <br />effective friction angle for the fines is uncharacteristically high. <br />Geowest's conservative decision to evaluate only the fines has limited EFCI's <br />ability to analyze a layering scenario on the pile. Stress testing on the <br />coarse fraction would be necessary to perform a stability analysis on the <br />layered pile. As a consequence the Division is requesting additional field <br />sampling and verification as part of Abatement No. 2. <br />- ~-'- - - - <br />STATE OF C~LIII ~~~~~~~~~~~~~~~~ <br />