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2.0 ENVIRONMENTAL MONITORING PROGRAMS <br />Each component of the environmental sampling program is described in the following <br />subsections. An overview of the entire sampling program is provided in Table 2.1. Sampling <br />locations are shown in Plate 1 (Centennial North) and Plate 2 (Centennial South). <br />2.1 Groundwater Monitoring <br />The need for reliable groundwater sampling procedures has been recognized for years by a <br />variety of professional, regulatory, public and private groups. Groundwater quality monitoring <br />programs have unique needs and goals which differ fundamentally depending on the objectives. <br />Conscientious efforts to design this ground-water investigation have been performed in order to <br />provide an accurate characterization of the groundwater quality within the Centennial Project <br />area. <br />Figure 2 is a generalized, north-south geologic cross-section through the Centennial Project site. <br />Sand units within the Upper Fox Hills Sandstone are hosts to uranium mineralization throughout <br />the project. Groundwater samples were collected from Upper Fox Hills sands situated up- <br />gradient of, down-gradient of and within identified uranium resource areas. In addition, water <br />quality samples were collected from an underlying aquifer in the Lower Fox Hills Sandstone (B <br />Sand) and overlying aquifers in the Laramie Formation. This sampling program was designed to <br />obtain site-wide water quality data in order to establish the overall water quality conditions for <br />the Laramie-Fox Hills aquifer within the Centennial Project area. Groundwater sampling and <br />water quality characterization activities targeting specific operational areas will continue <br />throughout the life of the project. <br />Initially, consistent with applicable guidance, groundwater samples were to be obtained quarterly <br />for five quarters, from twenty-one monitoring wells. These wells included seven historic wells <br />installed by RME, and fourteen new wells installed by R2 in 2007 (Plates 1 and 2). At the <br />request of DRMS, Powertech modified the SCP by adding three additional sampling events <br />during the five-quarter sampling period, for a total of eight representative samples per well. <br />Groundwater wells were sampled utilizing the "Purging and Sampling" method, in which three <br />well volumes are purged before parameters are checked for stability and the water sample is <br />collected. The analytical program for groundwater samples from monitoring wells is presented <br />in Table 2.2. Minimum sample volumes, preservation requirements, and holding times are <br />presented in Table 2.2. As part of groundwater sampling procedures, depth to groundwater level <br />and field parameters, i.e., pH, temperature, specific conductivity (SC), dissolved oxygen (DO), <br />and oxidation reduction potential (ORP), are measured and recorded. The samples were placed in <br />April 2009 5 Site Characterization Plan