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Sedimentation Pond Surveys <br />• SCC is required by Pe [mit C-BO-005 to monitor sedimentation ponds for sediment storage <br />capacities. In TR-15, CDMG approved the follows nq frequency schedule to conduct sediment <br />surveys for the ponds at Seneca II Mine. <br />Sediment orlon Pond Frequency Next Scheduled Survey <br />002 Once Every 5 Years 1998 <br />003 Once Every 5 Yeats 1998 <br />004 Once Every 2 Years 2000 <br />008 Once Every 2 Years 2000 <br />This schedule provides a sedSme nt yield history and gives advance warning to operations <br />personnel when sediment clean-out work is required. In accordance with Rule 4.05.611111c1, <br />SCC visually Suspects each pond a ml nimum of quarterly each year. During these inspections, <br />any drastic change in sedimentation storage or sudden Increase In a sediment delta a[ the <br />• inlet [o the pond could be detected which would require mitigation. No sediment clean-out <br />work was conducted during 1996 for the sedimentation ponds at Seneca II Mine. Sediment <br />Ponds 002, 003, 004, and OOB were surveyed In July 1993 for sediment determination. As <br />stated In [he past, ponds containing water are very difficult [o survey and obtain a high <br />degree of accuracy. In 1993, Seneca adopted a new approach [o sediment surveys. That is, <br />concentrating the survey shots in an area whe[e the most sediment deposition is likely [o <br />occur. <br />Based on [he 1993 survey, all sediment ponds have sufficient sediment storage. <br />Additionally, all ponds have been discharging in compliance with the approved NPDES permit <br />effluent limitations. Yearly sediment delivery estimates to [he ponds is considerably less <br />than originally calculated. <br />The fallowing data shows the latest calculated annual sediment delivery and existing <br />capacity. <br /> <br />6 <br />