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CMC — Henderson operations <br />DRMS 2014 Annual water Monitoring Report <br />May 2015 <br />Executive Summary <br />This report provides a summary of 2014 water monitoring data collected pursuant to the Climax <br />Molybdenum Company (CMC) — Henderson Operations (Henderson) Technical Revision 16 <br />(TR -16) to Permit M-1977-342 Groundwater Management Plan (GWMP). The Henderson <br />GWMP was approved by the Division of Reclamation, Mining and Safety (DRMS) in July 2012 <br />and, as such, this is the third submittal of this report. The focus of this report is 2014 data, <br />however, historical data is included from the 2012-2013 monitoring periods to allow for the <br />assessment of trends over time. Sampling was conducted at the required locations in accordance <br />with the GWMP and each sample was analyzed for the required parameters. <br />Mine Water Monitoring <br />A deviation below the numeric protection limit (NPL) of 6.5-8.5 pH was observed in the Mine <br />Point of Compliance (POC) well MNGW-1 in May, 2014. The well was resampled in June, <br />2014 and the pH value was again within the acceptable NPL range. A groundwater quality <br />investigation was previously initiated as a result of low pH measurements in 2012 and 2013. An <br />initial Groundwater Quality Assessment Technical Memorandum was submitted to DRMS in <br />December 2013 (AJAX and Clear Creek Associates, 2013). A subsequent Groundwater Quality <br />Assessment Update was submitted to DRMS in February 2015 (AJAX and Clear Creek <br />Associates, February 2015), detailing the drilling, logging, installation, and testing of two <br />monitor wells in the alluvial deposits north and west of existing POC well MNGW-1. <br />Henderson proposed to provide an update to DRMS on the data collected from the new wells <br />following at least three water quality sampling events, corresponding to fall 2015. <br />Mine water monitoring data for POC well MNGW-1 and non -POC long-term surface water <br />locations BG -20, CC -10 and CC -30 are included in this report and presented both in a table and <br />trend evaluation graphs. <br />Mill Water Monitoring <br />This report includes data from recently approved POC wells MLGW-15 and MLGW-17 as well <br />as incorporation and comparison against recently revised NPLs. There were no deviations from <br />established NPLs observed at Mill POC wells in 2014. <br />Mill water monitoring data for approved POC wells MLGW-ACR, MLGW-7, MLGW-15 and <br />MLGW-17 and non -POC long-term surface water monitoring locations WFR-20 and WFR-40 <br />are included in this report and presented both in a table and trend evaluation graphs. <br />3 of 7 <br />