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Ms. Erica Crosby March 3Q, 2007 Page 3 ELIMINATION OF STANDING WATER AND MONITORING: CURRENT CPIT C-Pit and Monitorine Well CEM-001 Analysis of currently available data indicates that a hydraulic connection exists between the water in C-Pit and the down gradient monitoring well CEM-001. CEM-001 is a 141.5-foot deep monitoring well located 800 feet southeast of the eastern wall of C-Pit. (See Figure 1, attached.) The 40-foot screen of CEM-001 runs approximately 10 feet above and below the Fort Hays Limestone contacts with the adjacent shale units. To confirm this hydraulic connection and track the response in CEM-001 as C-Pit is backfilled and the water level rises, Brown and Caldwell installed In-Sim Multiparameter Troll 9500 data logger units in both the C-Pit lake water and well CEM-001 on March 9, 2007. The data logger in C-Pit is deployed in a 40-foot length of PVC well casing with a 10-foot screen located at the northeast highwall of the pit. The casing will remain at this location while C-Pit is backfilled, and should provide an access point to the subsurface fox Future monitoring as necessary. Additional lengths of well casing will be added to the current configuration iE the filling of C-Pit requires it to be extended to a higher elevation. These recording monitors will remain in place fox approximately two months, and will record static water level, temperature, pH, conductivity, dissolved oxygen, and oxidation/reduction potential (ORP). Initial data collected by these units has been factored into the planning of the TR-8 hydrogeologicalinvestigations. OBJECTIVES FOR TR-8, HYDROGEOLOGICAL INVESTIGATION The objectives of the TR-8 hydxogeological investigation will be to assess and characterize potential sources of water entering C-Pit, and to sufficiently characterize the hydrogeology of C-Pit and the surrounding area to provide a basis for future monitoring and assessment of potential impacts from disposal of cement kiln dust (CKD) at this location. The plan also includes the installation of a compliance well at the southeastern extent of the site. This well will supersede any other wells in earlier monitoring plans. SCOPE OF WORK The proposed Scope of Woxk will consist of the Following elements, further described below: • CompIle available historical and operational information fox Bouldet Feeder Canal, the Swede Ditch, and the Highland Ditch in the area of the CEMEX Lyons facility. • Conduct a comprehensive site visit to confirm area geology, ditch flow gauging station locations, piezometer and well locations. • Investigate ditch seepage losses through gauging. • Install piezometers and monitoring wells at multiple units/depths. • Install a compliance well in the Fort Hays Limestone unit downgxadient of C-Pit and the existing well CEM-001. • Conduct an initial round of water sampling for chemical analysis at those locations where groundwater is found. -0594686.doc