Laserfiche WebLink
December 2013 <br />Mine Groundwater Quality Assessment ♦ 3 <br />2.0 SUMMARY OF GEOLOGY AND HYDROGEOLOGY <br />2.1 SITE GEOLOGY <br />The bedrock of the area surrounding the Henderson Mine site is relatively shallow and is <br />composed primarily of Precambrian Silver Plume Granite and Tertiary Period stock and dike <br />granitic intrusions that are highly altered by hydrothermal activity. The intrusions are <br />upgradient from the mine site and may produce significant naturally occurring background <br />concentrations of dissolved metals in the groundwater. The Vasquez Fault and a related <br />fracture zone may affect the groundwater flow, but the fate of any percolation into the fault <br />would be recirculation into the established Mine water system. The expected fate of all other <br />potential contamination would be accumulation in the stream flow and shallow groundwater <br />associated with alluvium near the West Fork of Clear Creek (WW Wheeler and Associates, <br />1991). <br />2.2 SITE HYDROGEOLOGY <br />Groundwater occurrence at the Henderson Mine is primarily limited to a thin, well- defined <br />lens of alluvium which is bounded on all sides by the Precambrian Silver Plume Granite <br />Formation. Groundwater occurrence within the Precambrian Silver Plume Granite is limited. <br />Groundwater occurs within glacial and alluvial deposits near and adjacent to the West Fork <br />of Clear Creek. Groundwater flow is generally from the upper end of the drainage to the <br />lower end. Upgradient of the confluence with Woods Creek, the alluvium pinches out and <br />groundwater is forced to surface into the West Fork of Clear Creek. <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 />