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i <br />DEPARTMENT OF NATURAL RESOURCES <br />David H. Getches, Executive Director <br />MINED LAND RECLAMATION DIVISION <br />DAVID C. SHELTON, Director <br />Richard D. Lamm <br />Governor <br />~nJOe%~ <br />6 <br />~~ ~~ <br />DATE: 5 June 1984 <br />MEMORANDUM <br />T0: Jim Herron <br />FROM: Jim Pendleton <br />RE: Supplement Comma - Coal Ridge No. 1 Underground Coal Mine <br />Applicati n's technical Adequacy - Coal Processing Waste <br />Embankment's "Seismic Exposure" <br />In my memo to you, dated May 23, 1984, I indicated that I had referred the <br />Storm King application documents concerning "Seismic Exposure" of the Coal <br />Ridge No. 1 Mine's proposed coal processing waste embankment to the Colorado <br />Geological Survey for review. I received the attached memorandum from Walter <br />R. Junge, Engineering Geologist with the CGS. <br />In completing their analysis of the proposed embankment's slope stability, <br />Chen & Associates, Inc., consultant to Storm King Mining, analyzed two <br />separate embankment conditions. The first was assumed to represent the <br />operational situation; i.e. a saturated embankment and slurry impoundment. <br />The consultant applied a pseudo-static earthquake coefficient of 0.059 to this <br />situation to model the potential effects of earthquake occurrence anticipated <br />during the short term. The second situation was assumed to represent the post <br />reclamation long term situation; i.e. a dewatered embankment and slurry <br />impoundment. The consultant applied a pseudo-static earthquake acceleration <br />coefficient of 0.109 to this situation to model the potential effects of <br />earthquake occurrence anticipated during the long term. <br />Mr. Junge recommends, and I concur, that the applicant be required to assume <br />psuedo-static earthquake acceleration coefficient of O.IOg in analyzing the <br />slope stability of the short term operational embankment situation. The <br />applicant should be required to amend the analysis appropriately for our <br />review. Should the applicant wish to contact Mr. Junge to discuss his <br />recommendation, I suggest that we coordinate any necessary meetings, in order <br />to keep our office appraised of the situation. <br />attachment: <br />cc: Walter R. Junge, CGS <br />Brian Munson <br />Document No: 1821E <br />423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. (30z) 866-3567 <br />~ III IIIIIIIIIIIII III <br />