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Responses to Division Concerns <br /> Page 9 <br /> Samples and flows of the South Fork of Cement Creek will <br /> be taken twice yearly during low flow to aid bromide <br /> detection (probably October and February) . If bromide is <br /> detected, it will be traced upstream to the source. <br /> - Sampling of Placer Gulch or California Gulch will not be <br /> necessary until the mine pool is above 11, 500 feet. <br /> Sampling for bromide will be performed annually during <br /> low flow to aid bromide detection (probably September) if <br /> the mine pool elevation exceeds 11 , 500 feet. If bromide <br /> is detected, it will be traced upstream to the source. <br /> The sample sites will be just upstream (in each stream) <br /> of their confluence with each other . <br /> - Eureka Gulch will be sampled annually at Eureka during <br /> low flow to aid bromide detection (probably September or <br /> October ) . If bromide is detected, it will be traced <br /> upstream to the source. <br /> - The American Tunnel flow before treatment is sampled <br /> monthly. Bromide will be added to the analysis list. If <br /> bromide is detected significantly above the level <br /> established as normal during concentration monitoring <br /> after valve closure, the cause will be investigated. <br /> - This monitoring program will remain in place for five <br /> years or until the mine pool has approached equilibrium, <br /> whichever is first . <br /> 2) Bulkhead Performance <br /> The Terry Tunnel and American Tunnel bulkhead designs <br /> provide a 1" diameter pipe for pressure gauge <br /> installation. These pressure gauges will be read during <br /> each bulkhead site visit to track the elevation of the <br /> mine pool surface and trigger the monitoring of Placer <br /> Gulch and California Gulch at their confluence if the <br /> elevation exceeds 11 , 500 feet. This information can also <br /> be used to limit the search area if bromide is detected <br /> during routine stream monitoring by defining the maximum <br /> possible elevation of the source. <br /> In the most likely scenario (Simon Hydro-Search March 12, <br /> 1993) , the equilibrium water level will be approximately <br /> 11, 500 feet. This is approximately 70 feet below the <br /> elevation of the Terry Tunnel bulkhead . If this is the <br /> case, the only head that will be on this bulkhead will be <br /> that required to back water up to a direct connection to <br /> the mine pool (approximately 30 feet) . <br />