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Apri122, 1999 ~ ~ Page 1 2.0 GROUNDWATER MONITORING LOCATIONS This groundwater monitoring plan presents detailed descriptions of the monitoring well layout, well completions, and groundwater monitoring zones. The Yankee Gulch Lease site will have 24 monitoring wells. The Pazachute site will have at least one monitoring well. The groundwater monitoring procedures are described in Section 3.0. 2.1 Yankcc Gulch Lease Site American Soda will use a network of 24 monitoring well completions (as detailed in Figure I) to monitor groundwater quality and water levels at the Yankee Gulch site for the 0-5 year mine panel. The Upper Aquifer will be monitored at 11 locations, the Lower Aquifer will be monitored at 9 locations, and the Alluvial Aquifer will be monitored at 4 locations. In addition to the ]0 existing monitoring wells, American Soda will construct 3 new multiple-completion monitoring wells and 3 new alluvium monitoring wells. Two of the proposed alluvium monitoring wells and an existing monitoring well will monitor the water level and quality of the Alluvial Aquifer adjacent to Piceance Creek. A fourth alluvium monitoring well will be completed downstream of the proposed upper plant settling pond to monitor for discharge and quality from the pond. The monitoring well layout for the Yankee Gulch lease site is shown on Figure 1. Figure 2 is a generalized stratigraphic column showing aquifer locations and important stratigraphic horizons. Monitoring well completion diagrams for existing wells are presented in Appendix A. The monitoring wells will be positioned up-gradient, down-gradient, and cross-gradient of the mine panel. American Soda has proposed this well configuration for the first panel to assure that potential impacts to groundwater and surface water will be detected. In addition, selected (retired) production wells within the 0-5 year mine panel will become part of the monitoring well network. 2.2 Monitoring Wcll Layout for the Yankcc Gulcl~ Lease Site The monitoring well layout for the Yankee Gulch site (shown in Figure 1) for the first phase of operations includes the addition of two multiple-completion wells located outside the 0-5 year mine panel, one multiple-completion well located within the 0-5 year panel, two Alluvial Aquifer wells located between the proposed mine pane] and Piceance Creek, and one Alluvial Aquifer monitoring well located down-gradient of the upper plant. These proposed wells will augment the Agapito Associates, Inc.