1992-08-07_REVISION - M1988112 (2)

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1 1 1 1 1 1 1 1 1 Geophysical Logging Colog, Inc. of Golden, Colorado, mobilized to the site on July 27, 1992 to geophysically log monitoring wells M-12 and M-13, as well as existing well M-9. The geophysical log suite that was run in each of these wells included gamma, neutron and EM conductivity Ipgs. Copies of the geophysical log suites run in each of these holes are presented in Appendix A. We have also reviewed the geophysical logs from condemnation holes 88-389, 88-390 and 88- 392 in an attempt to correlate beds within the Santa Fe Formation in the vicinity of the tailings facility and the collection pond. However, as the Santa Fe Formation consists of numerous channel sands and gravels interbedded with silt and mudstone units that are not necessarily laterally continuous, we were not able to detail definitive correlations among these logs. We believe that the most definitive expression of the bedding in the Santa Fe Formation is the outcrop exposed south of well M-12, which indicates a bedding plane dip of approximately 20 degrees to the northwest (see Hydrologic Assessment section). Aquifer Testing At the completion of the well installation and development, each of the monitoring wells completed in the local ground water table (M-9, M-12 and M-13) were pump-tested by means of aconstant-discharge test. During well development, pump discharges were measured from each well to evaluate what long-term pumping rate could be sustained at each of the wells. These data were used to set the discharge rates for each of the tests. The water level drawdown plots versus time for the pump tests at wells M-9, M-12 and M-13 are shown in Figures 4 through 6, respectively. The water level drawdown versus time data generated during each test are presented in Appendix B. The test pump was set at a maximum depth in each well so that maximum pumpping rates and pumping durations could be achieved for these tests. Discharge at the surface from each of these -4-