Laserfiche WebLink
l t <br />December 2013 Mine Groundwater Quality Assessment ♦ 1 <br />1.0 INTRODUCTION <br />This Technical Memorandum has been prepared for Climax Molybdenum Company's <br />Henderson Mine Operation (Henderson) to summarize groundwater water quality <br />downgradient of the Mine facilities. Monitoring and reporting requirements for the Mine are <br />pursuant to the Division of Reclamation, Mining, and Safety (DRMS)- approved Henderson <br />Groundwater Management Plan (GWMP), formally submitted as Technical Revision 16 <br />(TR -16) to the Henderson Mine and NO Reclamation Permit No. M- 1977 -342 (Henderson, <br />2012). <br />The Henderson Mine and NO is an underground mining operation that extracts <br />molybdenite ore from beneath Red Mountain and transports it via conveyor through a 9.6 <br />mile tunnel and 5 mile overland conveyor to the Henderson Mill. This Technical <br />Memorandum focuses on the hydrogeology and groundwater quality in the area east of the <br />Henderson Mine surface and underground facilities located west of Empire, in Clear Creek <br />County, Colorado. <br />1.1 BACKGROUND <br />Groundwater quality downgradient of the Mine area has historically been, and continues to <br />be, monitored at Point of Compliance (POC) well MNGW -1. The location of MNGW -1 in <br />relation to Mine surface facilities is shown on Figure 1. The monitoring well is constructed <br />in the alluvium and is representative of shallow groundwater conditions downgradient of <br />mine operations. <br />Henderson Mine installed MNGW -2, a deeper Precambrian bedrock well located <br />approximately one mile downgradient of MNGW -1, along the West Fork of Clear Creek <br />(see Figure 1), in 1993. This well has been dry since its completion. Henderson also <br />conducted a hydraulic conductivity study of the Precambrian Silver Plume Granite in the <br />URAD Valley and determined that groundwater flow in the bedrock unit is limited (WW <br />Wheeler and Associates, 1993). As a result of these findings, Henderson and the DRMS <br />agreed that MNGW -1 was appropriate for characterizing groundwater at the Mine. <br />AJAX Ltd ♦ 28828 Cedar Circle ♦ Evergreen, CO 80439 ♦ (303) 241 -2057 <br />Clear Creek Associates* 6155 E. Indian School Rd. ♦ Scottsdale, AZ 85251 ♦ (480) 659 -7131 <br />