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<br />ROY R. ROMER <br />GOVERNOR <br />COLORADO GEOLOGICAL SURVEY <br />DEPARTMENT OF NATUnALRESOURCES <br />715 STATE CENTEN NIA °1;1L ~:.`:~ - 7373 SHERMAN STREET <br />DENVER, COLORADO 80203 PHONE (3031 866-26~ 1 <br />M E M O R A N D U M <br />i ti <br />i rt <br />TO: Jim Pendleton, Supervising Geologist, <br />Mined Land Reclamation Division <br />FROM: Wm. Pat Ro ers, Colorado Geological Survey <br />DATE: January 18, 1990 <br />SUBJECT: SEISMIC SAFETY PROVISIONS FOR BATTLE MOUNTAIN RESOURCES, <br />SAN LUIS PROJECT <br />JOHN W. BOLD <br />DIREOTOR <br />Per your request, I have reviewed pertinent parts of this application on <br />subjects related to seismicity. I have also had informal discussions with you <br />and Steve Renner and other MLRD staff and participated in two meetings with <br />Battle Mountain Resources and their geotechnical consultants. <br />In addition to the project-oriented seismicity study by Dr. Glass that was <br />submitted by Battle Mtn Resources I have consulted several articles and <br />sources, especially having to do with selection of a "pseudostatic <br />coefficient" for projects. These will be listed at the end of this <br />memorandum. My specific comments and recommendations are listed below: <br />1.) The data used, procedures followed, and analyses and recommendations <br />presented by the applicant are appropriate and are adequately <br />conservative if the proposed dewatering system performs as projected. <br />2.) Because the seismic performance of the tailings empeundment is hi <br />dependent on liquefaction not occurring on an extensive scale <br />3.) There is a third item that was discussed but not resolved at our <br />meeting with the applicant on January 16th. This does not pertain to <br />the seismic safety of the empoundment but of the processing <br />facility. Given the acknowledged potential seismicity of the site it <br />would seem essential that the facility be designed for at least UBC <br />Seismic Zone 2 (this would be about .15g bedrock acceleration). <br />There was uncertainty on the point by the applicant at our last <br />meeting as to what pa ameter was used. The more conservative <br />zonation is needed be:.ause of personnel and hazardous materials <br />safety considerations. Clarification is needed on this point. <br />G E O L O G Y <br />STORY OF THE PAST... KEY TO THE FUTURE <br />