2011-09-09_REVISION - M1977493 - Laserfiche WebLink

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- Please provide DRMS with final locations of EVMW -2 and any surface springs selected for long term sampling if these locations are modified from the revised Figure 3 provided to DRMS. Tenmile Creek Basin - Well construction details and historical data have not been provided for GMW -1. GMW -1 appears to be a valuable internal monitoring point that should be included in the WQMP. Please detail why this well should not be included in the EPP/WQMP. If GMW -1 is not suitable, will new wells be installed to replace it for internal groundwater monitoring below 5 Dam and upstream of GMW -2? Water Quality Monitoring Plan — general comments Page 4 of 5 - The Division will require some attempt to identify, characterize, and monitor deeper groundwater (bedrock vs. alluvial) in the three drainage basins. DRMS suggests that bedrock wells be installed adjacent to all existing alluvial groundwater monitoring locations, and that all new wells are installed as nested pairs (one shallow alluvial and one bedrock well). NPLs for deep groundwater wells (and all other new monitoring wells) will be established in the same fashion as currently proposed - based on CBSG Table Values or on sampling data if table values are exceeded during baseline sampling. - There is a strong connection between alluvial groundwater and surface water on this site, with alluvial groundwater certainly discharging directly to surface water in these three drainage basins via the groundwater to surface water pathway. The surface water in these basins is classified as "Aquatic Life Cold 1" among other uses. The Division acknowledges that Tenmile surface water drainage is managed by a CDPHE Colorado Discharge Permit System (CDPS) permit; however this is not the case for the Arkansas River and East Fork Eagle River drainages at this time. As required by 6.4.21(11)(a) in the Hard Rock/Metal Mining Rule, please provide the receiving stream standards and any existing surface water quality and flow data for the Eagle and Arkansas drainages upstream and downstream of site activities. The rule requires "a minimum of 5 successive quarters and such other additional data, or a period specified by the Office, as may be necessary to adequately characterize baseline conditions." Please review sections 6.4.21(11)(a), (b) and (c) and address as appropriate. The Division believes that surface water monitoring both up- gradient of mining activity (background) and near the permit boundary down - gradient of the site should be conducted in the Eagle River and Arkansas River Basins. This will enable Climax and the Division to establish background conditions for these drainages, monitor for changes over time, and help determine if any observed changes may be attributable to site activity or groundwater to surface water discharge. It will need to be determined what "background/baseline" concentrations are in these drainages for analytes of concern (such as zinc and copper), and how this compares to data from downstream of the site Analytical methods used for surface water analysis will need to be able to report sufficiently low detection levels to compare to surface water aquatic life standards. Please address. - The Division will require for all monitoring points at least 5 quarters of full Target Analyte List (TAL) dissolved metals (including Hg), total and WAD cyanide, SO HCO NO3 +NO2, F, Cl, TOC, hardness, and total alkalinity. Please update Section 6.0 accordingly. This list may be evaluated and reduced after at least 5 full quarters of data have been collected and evaluated for all monitoring points. - NPL for WAD cyanide will be 0.2 mg/L or less for all groundwater monitoring points. - DRMS views NPLs as trigger levels — statistical analysis is not required. If an established NPL is exceeded, it will trigger the steps listed in section 5.1.2. DRMS will need to be notified to collect split samples of any required confirmation sampling for NPL exceedences.