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Fe(mcziy 1999 HG Gul Cosgtary " ]998 Anara(Redmlxmm Repro ~ Pste 9 <br />6.0 SEDIMENT PONDS <br />• 6.1 NPDES QUARTERLY REPORTS <br />HGCC personnel observed Pond 003 discharging from April through October. Pond HG-8 was <br />observed discharging during every month of 1998. Monthly pond discharges were collected for <br />laboratory analysis and quarterly monitoring reports were submitted to the Colorado Deparrmen[ of <br />Public Health and Environment. Copies of the quarterly discharge monitoring reports are found in <br />Exhibit 6, Discharge Monitoring Reports. <br />6.2 QUARTERLY INSPECTIONS <br />Quarterly pond inspections were performed for both Pond 003 and Pond HG-8. All inspections <br />indicated that there were no problems with either pond. Copies of the quarterly pond inspection <br />reports are found in Exhibit 7, Quarterly Pond Inspettion Reports. <br />6.3 SEDIMENT SURVEY <br />HGCC has conducted numerous sediment surveys of Ponds 003 and HG-8 since 1985. In addition, <br />several calculations of sediment yield have been performed. The sediment surveys and yield <br />calculations demonstrated chat the excellent revegetation success on the reclaimed mine site has <br />resulted in insignificant sediment delivery to the ponds during recent years. As part of the Phase <br />II/Phase III bond release application, HGCC demonstrated that the two sediment ponds were no <br />longer the primary technology controlling erosion and sedimentation ac the reclaimed mine site. As <br />part of the bond release application, HGCC has requested that these two ponds no longer be <br />• classified as sediment control stnrctures. CDMG performed an independent review, dated December <br />2, 1998, that compared pre-muung and post-muting sediment yields on the mine area chat drains to <br />pond HG-8. CDMG concluded that, based on the post-mining vegetative cover, the poso-mtning <br />sediment yield is less than the pre-mining sediment yield. <br /> <br />Morubnlery Woman ' P.O. Boz 774018 • Stennlcnt Splv~rs, Qdmrrlo 80477 • (970J 8796160 <br />Y!\A1)UraW Fq.e\lnIV+YI An.~pdmmrRgm <br />1/Ii9Yh <br />