2009-03-06_REVISION - M1983141 (4)

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Cash MineWaterMonitoring AdHanBrown 3.2.2 Monitoring FreauencY Monitoring will be attempted at the surface water locations on a quarterly basis, at the same time as the companion groundwater sampling is performed. if water is flowing in the stream beds at the time of sampling it shall be sampled. MRV reserves the option to petition DBMS to revise the monitoring frequency at a later date if conditions warrant. 3.2.3 Monitorinq If there is flow in the stream the rate shall be estimated by visual inspection of flow rate using the floating stick method, and measurement of the cross sectional area of the flow. Surface water sampling shall be conducted using the Standard Operating Procedure: SOP07 - Surface Water Sampling. Field parameters for the surface water samples shall be measured as specified in SOP11- Measuring Field Water Parameters. Groundwater samples shall be preserved and transferred to the laboratory as described in SOP03 - Sample Custody, Handling, Packing, and Shipping. The samples shall be analyzed at the laboratory for the parameters set forth in Table 1. Dissolved parameters shall be obtained from analysis, using filtration to 0.45 micron to be performed on-site, immediately after sampling. 3.3 Groundwater ¦ 3.3.1 _Monitoring Locations MRV proposes that the condition of groundwater at the minesite will be monitored by three monitoring locations. The locations of the monitoring wells are shown on Plate 4, and a description and the rationale for each is described below. ¦ 3.3.1.1 Upgradient Well An upgradient well will be utilized to identify the quality and level of water upgradient of the mine. This well will monitor the quality of water entering the area of the mine, which will act as a background concentration for consideration of impact caused by the mine. The well to be used is Monitor Well MW-1, located downgradient of the Gold Hill Mill and upgradient ' of the Cash Mine, as shown on Plate 4. This well is 188 feet deep, and was drilled by the United States Bureau of Mines in the late 1960s for research on tunneling. A well log is not available for its geology or construction. However, inspection of the well indicates that it has an 8" diameter steel collar casing to a ' depth estimated at 20 feet, and is open below that depth. Depth to water ranges between 15 and 35 feet. The upgradient well will be reconstructed prior to utilization for monitoring. The reconstruction will ' involve flushing the well, installation of 90 feet of alternating 2" PVC screen and casing in 10 foot lengths, located in a 100 foot long interval filled with 10/20 screen gravel pack. The remainder of the hole will be cased with Schedule 40 2" PVC, and the annulus will be sealed with bentonite slurry to the ' collar. The proposed completion is shown in Plate 5. The completion will be conducted in accordance with SOP04 - Groundwater Monitoring Well Installation (attached). After completion of the well, it will be developed by pumping or bailing, in accordance with SOP05 - Monitor Well Development. The well will then be tested for permeability in accordance with SOP06 - Single Well Testing. 1601A-20061106 4