2014-01-29_HYDROLOGY - P2009025 (8)

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Baseline Hydrologic Monitoring Plan — Hansen Project 3 1.2 Mining History Uranium was discovered in the volcaniclastic rocks of the Tallahassee Creek District in the 1954 (Chapin, et al., 1983). Mining commenced at several small mines in the district, including the Sunshine Mine (located near the confluence of the Middle and South Fork of Tallahassee Creek) and the Mary L. Mine (located at the foot of Soapy Hill). From 1954 to 1972, 16 small open pit and underground mines were operational (Chapin, et al., 1983) and by the late 1960s about 440,000 pounds of U3O8 had been produced (CGS, 2006). In the late 1970s, the Hansen Deposit and surrounding area was investigated by Cyprus Mines Corporation (Cyprus). Approximately 1,250 exploration holes were drilled in the area. Cyprus determined that the Hansen deposit contained significant uranium (over 25 million pounds) at a low grade (0.08 percent U3O8) (Dickinson, 1981). Mine permits were obtained by Cyprus for the Hansen Deposit and nearby Picnic Tree Deposit in 1980. Due to falling uranium prices, the Hansen and Picnic Tree deposits were not mined, and the property was eventually divided into 35+ -acre parcels and sold as the South T -Bar residential development. 1.3 Previous Investigations Extensive hydrologic studies were conducted in the area from 1977 to 1981 for permitting the Hansen Project. Hydrologic data are available from 92 monitoring wells, 16 routine surface water monitoring stations, and approximately 34 domestic water supply sources monitored from 1978 to 1981. In developing this baseline monitoring plan, data was obtained from the following documents and sources: • Hansen Project Summary Environmental Report, prepared by Cyprus Mines Corp / Wyoming Mineral Corp., August 1979 • Hansen Project Environmental Hydrology Report and Appendices, prepared by Wright Water Engineers, Inc., August 1979 • Hansen Project Baseline Water Quality 3/78 - 10/81, prepared by Wright Water Engineers, Inc., December 31, 1981 • Hansen Project Echo Park Aquifer Test - Interim Report, prepared by Wright Water Engineers, Inc., February 1979 • Hansen Project Groundwater Investigation Proposed Tailings Disposal Area, May 1980 • Dewatering Modelling Study, Hansen Project Open Pit Uranium Mine, Fremont County, Colorado, prepared for by Geo -Hydro Consulting, September 1980 The current baseline monitoring program for groundwater and surface water began in fall 2008 and has included quarterly and annual sampling of streams, springs, and monitoring wells in and around the Hansen Deposit and greater Taylor Ranch Project Area. Semi - annual or annual sampling of domestic (homeowner) water wells has also been conducted since fall 2008. Initially, a separate monitoring plan was developed to address baseline data collection for domestic water sources in the area (Whetstone, 2008b). The domestic water sampling program is being combined with the baseline monitoring program for surface water and monitoring wells with this revision of the monitoring plan. The following documents summarize the recent and ongoing monitoring programs: Whetstone Associates, 2008a. Taylor Ranch Project Baseline Hydrologic Monitoring Plan. Document #4153A.081006, prepared for Black Range Minerals, October 6, 2008. 32 pp plus figures. 4153A.140129 Whetstone Associates