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• 1999, however, the fluctuation in individual readings over the year has stabilized. TCC will continue to monitor <br />[his [rend. <br />Monitoring was initiated at Trout Creek alluvial well 008-AT-I during 1994. During 1999, no unusual <br />observations are noted with respect to the Trout Creek alluvium groundwater levels. No unusual observations are <br />noted with water quality remaining comparable [o alluvial wells upstream of the site. Monitoring was initiated at <br />Middle Creek alluvial well AVM-1 during 1996. During 1999, no unusual observations are noted with respect to <br />[he Middle Creek alluvium groundwater levels. No unusual observations are noted with water quality <br />characteristics comparable to other alluvial wells in the area. <br />Recorded surface water Flows for Foidel Creek, Fish Creek, and Trout Creek were relatively high compared to <br />TCC's period of record. TDS concentrations a[ site 1005 on Trout Creek, downstream of all mining operations, <br />peaked a[ 510 mg/I in July. TDS concentrations at site 800 on Foidel Creek, upstream of the mine facilities, <br />peaked at 3440 mg/I in August. TDS concentrations at site 8 on Foidel Creek, downstream of the mine facilities, <br />peaked at 3210 mg/I in July. No other notable water quality impacts are evident at any surface water sites <br />monitored during 1999. <br />Recorded 1999 spoil spring discharges remain negligible and, therefore, did not constitute a significant portion of <br />discharge from the TCC mine area with the potential [o impact off-site areas. Discharges from sedimentation <br />ponds predominately occurred in conformance with applicable NPDES penni[ limitations and therefore did not <br />• constitute significant impacts to receiving waters. Mine water discharge sites 109 and 115 produced little water <br />during the 1999 Water Year. No unusual occurrences of inFlow were noted as a result of the Annual Mine InFlow <br />study with total inflows occurring at lower than predicted rates. <br />When pumping mine water from the Fish Creek Borehole (mine discharge site 115) the flow becomes a <br />contributor [o sulfate levels in Fish Creek. When pumping mine water from the EMD Dewatering Well (mine <br />discharge site 109) the Flow becomes a contributor to sulfate levels in Foidel Creek. Fish Creek and Foidel <br />Creek, in turn, contribute [o the sulfate levels in Trout Creek. Trout Creek has a secondary drinking water <br />standard limiting sulfate to 250 mg/I. Historic sampline at sitz 1005 has shown that a sulfate level of 250 mg/I <br />correlates to a conductivity of 750 unthos/ctn. In order to quatttify the predicted effect of sulfate contributions <br />from sites 1 I ~ and 109, TCC in association with a consultant, has developed a computer program -the "FCBH <br />Calculator". In the winter, when stream gauging is difficult, the FCBH Calculator uses the flo+a of the Yampa <br />River below Steamboat Springs (USGS 09239500), to predict the Flow in Fish Creek (site 1005) and Trout Creek <br />(site 69) above their confluence, and in Trout Creek (site 1005) below the conluence. In the summer, the FCBH <br />Calculator uses measured Flows at these sites. Then, using measured Flow and conductivity at sites 115 and 109, <br />along with measured conductivity at sites 69 and 1005, the program calculates how much additional mine water, <br />if any, may be discharged from sites 1 15 and 109. TCC uses this method to ensure that the controllable discharge <br />from site 1 15 does not create a sulfate esceedence in Trout Creek. <br />LJ <br />-15 <br />