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Status Report; Robinson Seep Investigation Climax Molybdenum Company <br />1.0 INTRODUCTION <br />The Climax Molybdenum Mine is located on Fremont Pass, approximately 13 miles north of <br />Leadville, Colorado. The Eagle River Watershed is the particular focus of this study, located in <br />the western portion of the Mine property. <br />In early 2013, following routine monitoring in accordance with the Water Quality Monitoring Plan <br />(Tetra Tech, 2011), water quality in monitoring well EVMW -1S indicated an apparent increasing <br />trend in dissolved iron, dissolved manganese, sulfate and total dissolved solids (TDS), indicating <br />process water seepage from Robinson Lake below the Robinson Lake seep collection system. <br />1.1 Objective <br />This report provides the data and findings from the 2014 drilling investigation in the upper Eagle <br />Basin, conducted at Climax Molybdenum Mine during August 2014. The objectives of the 2014 <br />drilling /sampling program included: <br />• Evaluate temporal changes within the seepage downgradient of Robinson Lake seep <br />collection system (based on sulfate concentrations) since the 2013 field program <br />(Tetra Tech, 2013); <br />• Further delineate seepage (sulfate) concentrations in shallow groundwater <br />downgradient of the Robinson Lake seep collection system; and <br />• Evaluate hydrogeological properties of the alluvial hydrostratigraphic unit at EVMW- <br />1 S, downgradient of the Robinson Lake seep collection system. <br />Additionally, this report provides an update to the current hydrogeochemical monitoring in the <br />vicinity of EVMW-1S based on the most recent data and interpretations from the <br />increased monitoring in the area through the September 2014 sampling event. This work was <br />performed consistent with recommendations made in the November 2013 Status Report (Tetra <br />Tech, 2013). <br />1.2 Monitoring Program <br />Groundwater quality within the upper Eagle Basin has historically been monitored quarterly at the <br />EVMW monitoring well, constructed in September 1993, located below the Robinson Lake seep <br />collection system and above Eagle Park Reservoir. EVMW -1 S and a deeper, paired well (EVMW- <br />1D), were constructed in October 2011. EVMW-1S is completed within both unconsolidated <br />alluvium /till material and underlying weathered bedrock and was constructed to replace <br />monitoring well EVMW which had partially filled with silt. <br />Due to the apparent increasing trends observed in EVMW-1S, Climax immediately notified the <br />Colorado Division of Reclamation, Mining and Safety (DRMS) and the Eagle Park Reservoir <br />Company via the Eagle River Water & Sanitation District (ERWSD) and increased the sampling <br />frequency to monthly intervals for wells EVMW-1S, EVMW-1D, and EVMW -004, along with <br />collecting monthly water quality samples from Robinson Lake and the Robinson Lake Seep in <br />April of 2013. <br />Tetra Tech November 2014 <br />