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TR -18 to Permit M- 1977 -342 <br />Environmental Protection Plan <br />8. GROUNDWATER INFORMATION <br />Groundwater issues at hard rock mine sites are regulated through the DRMS under authority of <br />Senate Bill 89 -181. Henderson has prepared and submitted a Groundwater Management Plan, <br />Technical Revision 16 (TR -16) to the DRMS which outlines practices and procedures to protect <br />groundwater quality pursuant to Rule 3.1.7(5) of the Mineral Rules and Regulations of the <br />Colorado Mined Land Reclamation Board for Hard Rock, Metal, and DMOs. <br />TR -16 establishes permit conditions, including numeric protection levels (NPL) protective of <br />ground and surface waters. TR -16 is an important component of this EPP. <br />The following is a general summary of the water bodies, site geology and site hydrogeology in <br />and around the mine and mill sites as it relates to groundwater. More detailed information and <br />related references have been developed and submitted as a part of Henderson's Reclamation <br />Permit (as revised and amended), including TR -16. <br />8.1. Water Maps <br />Figures 1 and 2 depict surface water bodies within the vicinity of the Mine and Mill. <br />8.2. Site Geology <br />8.2.1. Mine <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 inclusions that are highly altered by hydrothermal activity. The inclusions are <br />upgradient from the Mine site and may produce significant naturally occurring <br />background 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 the West Fork of Clear Creek. <br />8.2.2. Mill <br />The Henderson Mill and tailings storage facilities are located in the Ute Creek Basin of the <br />Williams Fork drainage basin. The Ute Creek Basin is bounded on the west by the Vasquez <br />Mountain Range and bounded on the north, south and east by northwest trending Williams Fork <br />Mountains. The Ute Creek Basin basement rocks consist of weathered and unweathered <br />Precambrian gneiss and schist of the Idaho Springs Formation and Silver Plume Granite. In some <br />areas of the basin, the Miocene -aged Troublesome Formation consists mostly of unconsolidated <br />and semi - consolidated lensed clays, silts, sands, gravels and volcanic ash grading to consolidated <br />siltstone, sandstone, conglomerate and claystone derived from the weathering of the Williams <br />Fork Mountain Range. Pleistocene -aged glacial end - moraines, lake sediments and outwash <br />material encroach on the Ute Creek Basin and overlie the Troublesome Formation. End - moraines <br />are a conglomeration of boulders, cobbles, gravels, sands, silts and clays. Glacial lake sediments <br />cover low flat sections while glacial outwash was deposited in braided stream beds. Glacial <br />outwash consists of gravels, cobbles and sands. The Troublesome Formation is generally <br />blanketed by a 2 to 10 -foot thick layer of recent slopewash and residual soils. Alluvial material <br />generally lies within the present stream valleys. <br />Climax Molybdenum Company <br />Henderson Operations <br />October, 2012 <br />Page 25 of 40 <br />