Laserfiche WebLink
11 '_-Lq? <br />August 10, 2000 <br /> O <br /> e? <br /> F- <br /> a <br />A-1r Erich J. Bower <br />W <br />Environmental Engineer = <br />Climax Molybdenum Company U <br />Henderson Mill Q <br />19302 County Road <br />Parshall, Colorado 80458 Q <br />Subject: Response to Technical Revision No. 9, Stipulation No. 4 Tailing Dain Nc? <br />Decant Grouting, Henderson Mill, near Parshall, Colorado <br />Project No. 6800044400 00.9407 (T-G2000) <br />Dear Erich: <br />We have prepared this letter in response to Technical Revision No. 9 (TR-09), Stipulatiun No 4 <br />prepared by the State of Colorado Divisions of Minerals and Geology (DMG) dated April 21. <br />2000. Presented below is a summary of the request, a brief project history and a brief discussion <br />of our opinion. <br />SUMMARY OF REQUEST <br />We were requested by the Climax Molybdenum Company (Climax) to prepare a response of a <br />letter received from UMG. The DMG letter provides Climax conditional approval for bnsutincl, <br />the existing decant structure closed and is designated as Technical Revision No. 9 (TR-69) to <br />Permit No. hI-77-342. Conditional approval was given provided that four stipulations are suet <br />We have been requested to provide a response to Stipulation No. 4, which reads as lollows <br />The penetration of Nlc. 3-Dour bj, the abandoned No. z-Danr decant system couhl croule u <br />pulhivaj, or seepage and piping which a,-e potential daitt stabilio} issues. bt'ithin ot) Lkr ys <br />of date of technical revll'sion TR-09 approval, Xanclclrsorr must prus irle the I1ivi.riratr tiritlr rc <br />report on thispotential, ?chich mqy comprise records on the construction of Wo. 3-1)am <br />= thryj relate to they decant ,s),stent Penetrations, nt' if acleclucrte historical r"evoi-ds• are <br />unavailable Henderson mast provide the Division with a proposal to investiirwv thc <br />nature tvid cane ilion of the clecaw syste•» r penetrations <br />PROJECT HISTORY <br />Construction of the Henderson tailing dams began in the early 1970's. T,,vo darts were <br />constructed and are referred to as the Lower and Upper Tailing dam or Tailing Dann No l and <br />No. 2, respectively Both dams are constructed using the upstream method orlailing; <br />deposition. <br />J ;.WAtAS'EP~Pfti.,tE(;'S?i4?;i? ?¢? cox ob,jo?wj3 'i! <br />Fhl?