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TR-34 to Permit M-1977-342 <br /> Environmental Protection Plan <br /> 14. GEOCHEMICAL DATA AND ANALYSIS <br /> 14.1. Evaluation of Ore and Tailing Storage Facility <br /> The Henderson ore body contains unoxidized sulfides that, in the presence of oxygen, water and <br /> bacteria, have the potential to become an acid-forming material as defined in Rule 1, Section 1.1 <br /> (1). Henderson concurred with this fact when it accepted the DRMS determination that the <br /> Henderson Mine was a DMO under the amended rules. Thus, based upon discussions with DRMS <br /> personnel, development of specific geochemical data are not necessary for mill tailing material. <br /> 14.2. Evaluation of Development Rock Properties <br /> Water quality monitoring data collected and on file with the DRMS comparing metal <br /> concentrations above and below the Henderson Mine demonstrates that, after 40 years, the fill <br /> materials at the Mine is not causing adverse impacts to downstream water quality. Henderson <br /> maintains adequate controls in place to detect acid forming conditions and/or elevated <br /> concentrations of key parameters through routine surface and groundwater monitoring (see <br /> Sections 8-11). <br /> Furthermore, related to the development of the GWMP (TR-16), Henderson performed a <br /> geochemical evaluation of the Mine site fill materials in June, 2010 in order to identify key <br /> parameters that have a reasonable potential of being transported from mining materials to <br /> surface and groundwater systems and incorporating these parameters in the scope of ongoing <br /> surface and groundwater monitoring. <br /> The upper portion of the old railroad haulage route at the Mill, running from the portal for <br /> approximately the first 2 miles, is constructed of rock excavated during construction of the <br /> haulage tunnel. This material was tested for the potential to be acid producing. Acid-base <br /> accounting analyses were used to test six(6) grab samples collected from this stretch of railroad <br /> in June of 1995, and are presented in Appendix E. The data indicate that this fill material is non- <br /> acid producing. <br /> Climax Molybdenum Company August,2021 <br /> Henderson Operations Page 39 of 45 <br />