2009-09-25_PERMIT FILE - M2009076 (37)

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• 6.3.2(c) Water Resource Description: Surface Waters Clear Creek is located 2,800' to the south and 1,000' in elevation below the Tailings Impoundment affected area. Drainage from this area follows down Hukill Gulch. Historically, the drainage from this vicinity contains acid- runoff/drainage from the numerous abandoned mine waste rock piles and adits located throughout this gulch. Many of these sources are not within the control of Venture Resources (ie Colorado School of Mines owns over a dozen properties in this vicinity; one of which, the Edgar Union Lode, contains three large dumps that is 350' downgrade from the proposed Tailings Impoundment). The proposed operations and subsequent reclamation measures will remove the acidic contribution from Venture Resources' properties and proportionally reduce contamination to surface waters. The waste rock dumps on Venture Resources' property will be processed and re-impounded in a remediated state. Refer to Exhibit C and D for more information. It shall also be noted that this area is not within a floodplain (ref. FEMA Map 408019C0093D, Zone X attached in Exhibit C). Groundwater: There are no perched zones or traditionally defined aquifers in this mountainous area. The site is completely composed of crystalline Precambrian rocks, i.e. gneisses and schists, and tertiary intrusive rocks such as quartz monzonites overlain by 0-24" of unconsolidated material. Ground water wells within one mile of site boundary are detailed in a map attached at the end of Exdiibit C, sourced from the Colorado Division of Water Resources. It shall also be noted that the groundwater in this area is is unclassified per the Colorado Division of Water Resources. Unconsolidated materials, soils, of between 0 and 18"-24" overlay the crystalline rocks. The rocks themselves have essentially no porosity or permeability. Random, in-identifiable fractures due to jointing and faulting provide the only groundwater transmissivity and relative porosity. The site is underlain by numerous mine openings, the most important of which is the workings of the Shafter Mine. The vein of the Shafter Mine outcrops within 100 yards of the proposed disposal area, strikes N 40-60° W and dips 78-80° NW. The Shafter vein (along with the Great American and Edgar) is cut by the Big Five Tunnel at 4,250 feet from the portal, and at a depth of 893 feet on the dip of the vein. The mine workings effectively drain the area underneath the site. Refer to USGS Bulletin 1208, Plate 3, Geologic Section Along the Big Five Tunnel, Idaho Springer District, Colorado at the end of Exhibit C. Another example supporting this is the Colorado School of Mines Edgar Mine Facility (approx. 350' south of the proposed Tailings Impoundment). After a meeting with them on August 31, 2009, it was learned that their mine is "dry". So "dry" in fact that they are working on permitting a well on premises to supply a marginal water supply for drilling operations to keep the dust down. The starting elevation of their well is 7,793' and the borehole was drilled to-254'. Water was determined at -172'. This elevation, 7,621', just so happens to match the Big 5 Tunnel elevation. Safe to say another example of the drainage in this area. A copy of this well log is attached in the appendix of Exhibit C. Hydraulic conductivity for the undisturbed rock types present at the site, in-situ before mining, ranges from 10-2 - 10+z gallons per day per square foot (as reported by Freeze and Cherry (1979)) due to joints and fractures in the rock. These joints and fractures will be sealed with hydraulically applied clay that is part of the waste stream. The existence of the underground mine workings provide a direct hydraulic conduit for groundwater beneath the site. The Big Five tunnel, the major drainage for the area, lies 1,000 feet directly below the site. The Big Five Tunnel drainage is monitored, collected, and pumped to the Argo Tunnel Treatment Facility located in Idaho Springs. It produces on average, 35 gallons per minute. This tunnel was constructed in the early 1900's to access and drain the mines in this vicinity. The portal is located on the west end of Idaho Springs and the tunnel was driven 0