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' May 2014 Groundwater POC Update Memorandum♦1 <br /> ' 1.0 INTRODUCTION <br /> ' This Memorandum has been prepared for Climax Molybdenum Company's Henderson Mill <br /> Operation (Henderson) to further assess appropriate locations for point of compliance <br /> ' (POC) groundwater monitor wells downgradient of Henderson Mill's Tailing Storage Facility <br /> (TSF), specifically 1-Dam and 3-Dam, which are located within the Ute Creek Basin of the <br /> Williams Fork River Valley, south of Parshall,in Grand County, Colorado. Figure 1 presents <br /> a regional map showing the location and geographic setting of the Henderson Mill and TSF <br /> area. Monitoring and reporting requirements are pursuant to the Division of Reclamation, <br /> Mining, and Safety (DRMS)-approved Henderson Groundwater Management Plan <br /> ' (GWMP), formally submitted as Technical Revision 16 (TR-16) to the Henderson Mine and <br /> Mill Reclamation Permit No. M-1977-342 (Climax Molybdenum Company,2012). <br /> 1.1 BACKGROUND AND OBJECTIVES <br /> The groundwater quality downgradient of 1-Dam has historically been monitored at well <br /> MLGW-7. As described in the GWMP, Henderson recognized the need to evaluate and <br /> ' potentially establish new POC wells: (1) near the property line east of 1-Dam (near MLGW- <br /> 7 - see Figure 2), (2) in the Potato Gulch drainage (near MLGW-10 — see Figure 1), and (3) <br /> east of 3-Dam (see Figure 3) to provide adequate lateral coverage in areas downgradient of <br /> ' the TSF. Henderson further recognized the potential merits of establishing nested wells, to <br /> assess potential deeper groundwater conditions. In May 2013, these POC locations were <br /> ' evaluated and recommendations were provided in the POC Memorandum (AJAX and Clear <br /> Creek, 2013) submitted to DRMS. This POC Update Memorandum evaluates the previous <br /> recommendations based on additional groundwater quality data (five quarters of baseline <br /> data) and monthly groundwater elevation data collected since the previous evaluation. <br /> ' Updated recommendations are presented herein based on our review of these data. <br />