2010-02-16_PERMIT FILE - M2009076

Home Browse Search

Letter to Ryan J. McHale 6 February 16, 2010 Permit Application Adequacy Review File No M-2009-076 18. The Environmental Protection Plan at section 6.4.20(9)(a) provides discussion indicating that there is little or no existing or potential future use of ground water under the affected land. The DRMS has determined that the existing use of ground water underlying this site is surface water recharge, as indicated by the collection, treatment, and discharge to Clear Creek of Big 5 Tunnel flows. 19. The Environmental Protection Plan and Exhibit C discuss baseline ground water quality, propose a point of compliance for ground water, and numeric protection limits for ground water. The DRMS has identified the following issues with the ground water aspects of the permit application. a. Provide schematics for the monitoring wells illustrating the well bore and casing, the grouted and screened intervals, and the so1bedrock interface. b. Exhibit C states that ground water samples to be collected will be analyzed for RCRA metals. Instead of referencing RCRA, please clarify that the metals for analysis will be Al, As, Ba, Cd, Cr, Cu, Pb, Mn, Hg, Se, Ag, and Zn (DRMS will require analysis for Al, which was not included in the list in the permit application). c. Exhibit C states that ground water sample pH will be measured at an analytical laboratory. pH must be measured at the time of sample collection in the field by a method accurate to 1/10`h of a standard unit. Provide a plan to measure pH. d. The ground water sample collection plan described in Exhibit C does not include well purging prior to sample collection; ideally, three well bore volumes of water are removed prior to sample collection. Since the wells installed are likely to be dry, or to contain minimal water, DRMS recognizes the need to sample any water that can be retrieved from the wells. DRMS suggests that water from each bailer pulled from the wells be bottled, and that the last bottle filled when the wells goes dry or when three pore volumes are removed be analyzed. e. There is no discussion in the permit application for reporting of ground water monitoring results to the DRMS. The DRMS will require a report within five working days of pH and volume purged if water is encountered in the wells, with analytical results reported as soon as they are received from the laboratory. If the wells are dry during each sampling event, this must be reported in each annual reclamation report submitted to the DRMS. f. Based on the discussion in item 16 above, DRMS has determined the need for practice-based permit conditions protective of ground water. DRMS will require a tailing impoundment liner with a leachate collection system capable of limiting the hydrostatic head on the liner to less than three feet. Plans, specifications, and quality assurance protocols for a composite liner system must be provided. g. The proposed numeric protection limits at the down gradient well point of compliance based partly on the quality of the Big 5 Tunnel discharge are not acceptable. Any numeric protection limits that might be applied to this operation must be designed to prevent any significant increase metal load in the Big 5 Tunnel water. The DRMS has determined that practice-based ground water protection is appropriate for this operation. Therefore, depending on the responses to item 19a above, the primary utilization of the monitoring wells will be to detect liner leaks, rather than demonstrate compliance with numeric protection limits. 20. The Environmental Protection Plan states that "no extractive metallurgical processes (are) proposed as part of this operation." As a point of clarification, the DRMS definition of extractive metallurgical processes includes gravity and flotation concentration methods (Rule 1.1(18)). 21. The Environmental Protection Plan at section 6.4.20(10)(a) references storm water management designs provided in Exhibits C and E. The DRMS has identified the following issues with the information provided.