2009-03-19_PERMIT FILE - C1982057A (2)

Home Browse Search

Technical Revision 58 (2007) Monitoring Program Changes Due to the closing of the Seneca IN Mine, SCC has requested a reduction in monitoring frequencies of streams, springs and wells. These reduced monitoring frequencies will be continued until a year or two before final bond release, at which time monitoring frequencies will be increased. Table 1, Current Hydrologic Monitoring Program (pages 15-3a-4 to 6), has been revised to reflect these changes. The details of the changes are provided below. For ground water monitoring wells, the frequency of water level measurements has been changed from tri- annual to semi-annual (May/June and September/October). Water quality sampling of alluvial well GW-S2W- 21A (Sage Creek) will be changed from triannual to semi-annual. Water quality sampling of all other alluvial wells will remain unchanged (semi-annual, or in some cases, triannual). Water quality sampling of bedrock wells will change from semi-annual to annual (May/June), since the bedrock wells are subject to less change in water quality than the alluvium. Water quality sampling will be discontinued at wells GW-S2W-160V and 16W. This set of wells exists between the A/B and C/D pit areas in the north area. Well 160V often does not have enough water in it to sample. Well 16W often does not have enough water in it to sample, or is dry. Better monitor wells exists below the A/B pit (#17 series) and C/D pit (#14 series). These wells will remain open for sampling, if necessary, prior to bond release. For stream sites, monitoring at SW-S2W-SG5 (Dry Creek), SW-S2W-FG1 (lower Hubberson Gulch) and SW- S2W-FG4 (Sage Creek) have been changed from monthly to tri-annual (spring runoff, post-runoff and baseflow). For springs and spoil springs, monitoring has been changed from semi-annual to annual (May to July). All monitoring at Spring S-23 will be discontinued. This spring is located in a stream channel in an undisturbed area above Pond 006. It has an average flow of 1.15 gpm and a maximum flow of 10.3 gpm. Electrical conductivity and TDS values at this spring exhibit a stable trend. All monitoring at Spring S-48 will be discontinued. This spring is located in an undisturbed area above Pond 009. It has an average flow of 2.66 gpm and a maximum flow of 6 gpm. Electrical conductivity values at this spring exhibit a stable trend. Technical Revision 62 (2008) Mid-Term Review Monitoring of Spring S-50 (french drain at abandoned W-24 well site above Pond 016) and Spoil Spring 5 (above Pond 016A) will commence at the same frequency as other springs. Technical Revision 63 (2009) Ground Water Points of Compliance This technical revision assigned ground water points of compliance for the Yoast Mine. Details for this revision are found in Appendix 15-3B. TR-63 15-3a-11 Revised 1/09