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'S-= Golder <br /> Associiates TECHNICAL MEMORANDUM <br /> Date: June 2, 2014 Document No.: 1402712 001 TMO1 RevO <br /> To: Christopher Schmitz Company: Climax Molybdenum Company <br /> From: David Geier and Brent Bronson Email: DGeier(a-)Golder.corn <br /> RE: CLIMAX MOLYBDENUM OSF STABILITY EVALUATION— <br /> GEOTECHNICAL STABILITY OF INTERIM OSF CONFIGURATION <br /> 1.0 OBJECTIVE <br /> This memorandum presents the calculations performed to evaluate the global stability of the interim <br /> North 40 overburden storage facility(OSF)at the Climax Molybdenum Company(Climax) mine in Climax, <br /> Colorado. Golder previously completed a geotechnical stability evaluation of the proposed ultimate OSF <br /> geometry, which is included in the OSF design report (Golder 2012), which was submitted to DRMS in <br /> May 2012 as part of Technical Revision 22 (TR-22) to the Climax mine permit No. M-1977-493. Due to <br /> changes in the mine plan, Climax recently completed design of an interim North 40 OSF configuration that <br /> provides the required OSF capacity until the McNulty OSF can be made fully operational. The interim <br /> OSF configuration represents a temporary intermediate OSF stage between the existing OSF grades and <br /> the proposed ultimate OSF grades. The volume of overburden material to be placed during development <br /> of the interim OSF is entirely within the limits of the ultimate OSF (i.e., the interim OSF configuration does <br /> not change the ultimate OSF configuration previously evaluated). Therefore, the proposed ultimate OSF <br /> configuration and closure design evaluated in the OSF design report (Golder 2012) are still considered <br /> valid. Therefore,the stability of the interim OSF plan was not evaluated for post-closure conditions. <br /> A geotechnical field investigation consisting of 19 test pits and 7 boreholes was conducted in October and <br /> November 2011 and is summarized in the OSF design report (Golder 2012) and in Appendix A to the <br /> OSF design report. Representative samples collected during the field program were used to conduct a <br /> laboratory-testing program, the results of which are also presented in Appendix B of the OSF design <br /> report. The results of the field investigation and laboratory-testing program, in conjunction with other <br /> available information, including historical reports, existing topography, aerial photographs, and geologic <br /> maps, were analyzed to create the geologic cross sections including bedrock contacts and piezometric <br /> surfaces. The field and laboratory program results and historical reports were also used to determine the <br /> design parameters used in this analysis. <br /> I:\14\1402712\0100\0122\001 TM01 RevO\1402712 001 TM01 RevO ClimaxMolyOSFStabilityAnalysis 02JUN14.docx <br /> Golder Associates Inc. <br /> 44 Union Boulevard,Suite 300 Ar1 <br /> Lakewood,CO 80228 USA j <br /> Tel: (303)980-0540 Fax: (303)985-2080 www.golder.com <br /> Golder Associates:Operations In Africa,Asia,Australasia,Europe,North America and South America <br /> Golder,Golder Associates and the GA globe design are trademarks of Golder Associates Corporation <br />