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1998 Annual Update <br />Sunnyside Mine Bulkheads <br />Page 2 <br />1996 and completed in October of 1997 within the time period <br />allowed for in the Consent Decree. <br />The American Tunnel bulkhead valve was closed in September, 1996 <br />and the Terry Tunnel bulkhead valve closed in July, 1996. Since <br />September, 1996 the mine pool has been allowed to rise towards <br />physical equilibrium. As of the end of the report year (March 22, <br />1998), the mine pool had reached 11,418 feet M.S.L. Included in <br />Appendix B is monitoring data and a graph of the mine pool pressure <br />readings. Although the mine pool surface is in the zone of <br />predicted equilibrium, it does not appear that physical equilibrium <br />was reached during the 1997 report year. <br />STUDY UPDATE: <br />Attached in Appendix B is the data collected through March 1998 for <br />the seep, spring, and flowing adit inventory and monitoring <br />required by TR -14. <br />During the report year one new monitoring site was added and no <br />sites were deleted. This added site is a draining adit (Red and <br />Bonita) in the Cement Creek drainage which was observed to be <br />draining during the spring monitoring and was sampled. Although <br />this adit had not been observed by SGC to drain in the past, DMG <br />Inactive Mine personnel indicated to SGC that they had. SGC <br />believes this drainage was due to a high water table in 1997 (both <br />because of DMG's past observation and the adit was not draining <br />during the fall sample session) and was not related to the <br />Sunnyside Mine pool. <br />Sunnyside visited all identified sites twice during the report <br />year, collected field data, and sampled a more than the 20 percent <br />of the sites for lab analysis required for the monitoring program <br />(attached in Appendix B). Data summary sheets are also included in <br />Appendix B. <br />Data Analysis: <br />Seep, spring and flowing adit samples were taken in early summer, <br />when the sites became accessible and snow -melt would not bias the <br />samples, and fall before snowfall was expected to shut off site <br />access. The sampling efforts were spread over approximately a <br />month for each round. Early July was an approximate mid -point of <br />the early summer sampling round and late September for the fall <br />sampling round. The mine pool elevation was approximately 11,350 <br />feet MSL in early July and 11,375 feet MSL in late- September. <br />