2011-12-15_REVISION - M1977493 - Laserfiche WebLink

Home Browse Search

approval prior to the 2012 field season. If appropriate, a shallow /deep well pair will be completed if separate hydrostratigraphic units (alluvial and bedrock units) are encountered. The general area of the proposed new well site is shown in the revised WQMP. - Are any water quality samples collected currently from the 5 -shaft discharge or the Storke seepage collection site? This question also applies to all other TSF dam seepage collection sites, groundwater cut -off sites, or other discrete source of impacted water on -site. Again, water quality/quantity measurements of this impacted drainage may provide useful insight into geochemical processes at the site, document success of EPFs, and /or help to guide future treatment options for impacted drainage. As discussed previously in the response to comments on Acid Forming Materials and Acid Mine Drainage, water quality data are available for both the 5 Shaft and the Storke Waste Water Pump Station. These data are included in Appendix T -E of the revised EPP. In addition to water quality monitoring, the effectiveness of 5 Shaft pumping is verified by the water level in the piezometer adjacent to the shaft that shows a hydraulic gradient towards the shaft. Eagle River Basin - DRMS will require Climax to verify and monitor the effectiveness of the Dam 4 seepage cutoff system through the installation of a nested pair of groundwater monitoring wells immediately downstream of the final seepage cutoff and return structure. The Division would also consider other methods of verification, such as the collection and analysis of the impacted seepage vs. the surface water immediately down - gradient of the cut -off structure, if these alternative methods could be reasonably demonstrated to be reliable indicators of the success or failure of the cutoff structures. Due to site topography and presence of power lines there is insufficient room to safely construct monitoring wells below the seepage cutoff system. As discussed previously with DRMS, Climax believes that the only technically feasible groundwater monitoring location below 4 Dam (Eagle Park Reservoir) is the EVMW -3 site, where both shallow (alluvial) and deep (bedrock) wells were constructed in 2011. As described in the WQMP, the seepage collected in the 4 Dam Seepage Collection System averages only approximately 10 gallons per minute. Given the relatively small amount of impacted seepage, construction and monitoring of the new POC wells, proposed surface water monitoring in the East Fork Eagle River and below the Eagle Park Reservoir outlet works (as described in the revised WQMP), the redundancy of the collection system (two collection ponds and a cut -off wall), and the previous demonstrations of water quality in the East Fork Eagle River (performed as part of the remediation and surety reduction demonstrations for the Eagle Park Reservoir), Climax does not believe additional water quality monitoring is necessary. The channel immediately below the 4 Dam seepage collection system primarily conveys only water released from the Eagle Park Reservoir (EPR) and localized run -off from precipitation or snowmelt events. As part of its EPF monitoring program, Climax will incorporate a visual inspection of the stream channel below the seepage collection system and EPR outlet works during periods of no natural flow or discharge from the reservoir. - Eagle Park Reservoir has been removed from the permitted area and is now a source of surface water discharged directly to the East Fork Eagle River. Nested POC wells will need to be installed and sampled in at 9