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�. COLORADO OPERATIONS <br />® Climax Molybdenum Henderson Mine <br />A Freeport- McMoRan Company 1746 County Road 202 <br />Empire, CO 80438 <br />Phone (303) 569 -3221 <br />July 11, 2013 <br />Itacalvab <br />Via Email and UPS Tracking #: 1Z 804 847 03 7605 6763 <br />'A 12 2013 <br />Mr. Peter Hays DIVISION OF RECLAMATION <br />✓Division of Reclamation, Mining and Safety MINING AND WEN <br />1313 Sherman St., Rm. 215 <br />Denver, CO 80203 <br />Re: Mine Groundwater NPL Exceedance Notification, Permit No. M- 1977 -342 <br />Dear Mr. Hays: <br />Henderson Mine is providing this written notification of an NPL exceedance for pH at groundwater point of <br />compliance (POC) well MNGW -1, downgradient of the Henderson Mine, in accordance with Section 5.3 of <br />the Henderson Groundwater Management Plan. This written notification is subsequent to the verbal <br />notifications that were made to you on June 4, 2013 and during your inspection at the Henderson Mill on <br />June 20, 2013. <br />In the Annual Water Monitoring Report submitted on June 30, 2013, results from the December 11, 2012 <br />monitoring event were presented for MNGW -1, with a pH value of 6.4 standard units (s.u.). This <br />exceeded the numeric protection limit (NPL) of 6.5 -8.5. MNGW -1 was again monitored during the spring <br />runoff period on May 28, 2013, with a pH of 6.3 s.u., and a follow -up sample on June 19 also showed a <br />pH of 6.3 s.u. <br />Henderson performed a trend analysis and the results did not appear to be anomalous, or obvious <br />outliers. The monitoring frequency at this location for pH and a list of indicator parameters currently being <br />developed will be increased to once per month in order to better evaluate pH trends and the underlying <br />water chemistry that may be causing a low pH at this location. <br />Henderson proposes to provide a follow -up report to the DRMS by December 31, 2013, where results of <br />additional sampling at MNGW -1 will be provided, including a water quality assessment. The objective of <br />the water quality assessment will be to provide an understanding of potential causes of reduced pH which <br />can then be utilized to guide in further monitoring and /or develop a mitigation plan, as appropriate. <br />