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Mr. J. David Holm <br />Water Quality Control Division <br />Page 4 <br />response and monitoring activities. The cornerstone of the TR-26 response activities <br />consists of pumping groundwater from the backfilled West Pit to a lower water level such <br />that a cone of depression would develop in and azound the West Pit thereby reversing the <br />hydraulic gradient between the pit and the Rito Seco alluvial aquifer and surface flows. <br />Initial pumping and water management activities commenced in July, 1999. The water <br />treatment plant has been constructed and was commissioned in October 1999. The entire <br />pump and treat system has been fully operational since January, 2000 and has achieved <br />the desired water levels in the West Pit thereby reversing the hydraulic gradient as <br />anticipated in the projections set forth in TR-26. See Technical memorandum from Jim <br />Finley, Shepherd Miller, Inc. to Bill Lyle, BMG, dated January 25, 2000. <br />Alle¢ations of Continued Seeaage <br />A number of the public comments assert that seepage affected by the West Pit continues <br />to flow into the Rito Seco. These assertions are simply wrong. To the contrary, the <br />springs and seeps that were referenced in the NOV/CD, have been eliminated and, to our <br />knowledge no other springs or seeps potentially related to the West Pit have developed. <br />We aze advised that these observations have been confirmed by numerous, detailed on- <br />site inspections conducted independently by DMG, EPA, and your office, as well as <br />inspections conducted by BMG personnel and consultants. The results aze consistent <br />with pumping records for the French drain sump which indicate that the sump has been <br />dry since February 8, 2000 and in the monitoring records for the groundwater wells in the <br />backfill and downgradient Rito Seco alluvial aquifer. Moreover, surface water quality <br />monitoring data for the Rito Seco (RS-2) cleazly demonstrates that the system is <br />perforating according to plan resulting in a reduction of levels of manganese and sulfate <br />to levels consistent with pre-existing levels in the stream. Monitoring data supporting <br />these observations are on file at the DMG and will be provided in an updated summary <br />report under sepazate cover. One commenter asserts that he viewed continued seepage <br />from one of the historical seep locations on April 30, 2000. In point of fact, the seep <br />location described by the commenter cannot physically be viewed from the county road <br />