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-4- <br />11.0: "Surface water flows only in response to significant precipitation events the majority of which occur during the <br />summer monsoon season. Snowmelt may be a contributing component to surface water flow." <br />Comment: These two passages appear to contradict each other. Episodic events could produce enough <br />precipitation to generate off site discharge. Operator should incorporate the discharge contingency into the plan. <br />14.2: "the EPA has published soil radionuclide protective levels for migration to groundwater. These thresholds are <br />values below which migration to groundwater is not anticipated. The values for Radium226 and Radium228 range <br />from 3.26E-07 - 3.2E-01 and 1.15E-09 - 3.2E-01 respectively (units of mg/kg). Assuming a density of 1 g/ml the SPLP <br />results for these isotopes are considerably greater than the groundwater migration thresholds." <br />Comment: The EPA concentrations refer to solid media not aqueous, therefore the scenario is not as dire as <br />originally suspected. <br />14.2: "....water contact and release from the surface deposition material needs to be managed to protect any <br />underlying groundwater resource." <br />Comment: Please provide details of the management plan. <br />19.0: "Groundwater and associated subsections is not a concern. Referencing recent exploration drilling and current <br />mining activity, groundwater does not <br />occur at the site in any measurable amount." <br />Comment: Qualitative statements regarding the presence of ground water are not acceptable for a Designated <br />Mining Operation Environmental Protection Plan. Operator must provide data that include: <br />• depth to ground water at various locations around the property so that the potentiometric surface and <br />hydraulic gradient are well defined; such data must be presented for each aquifer in the area that stands a <br />chance of being impacted by site operations or reclamation activity. <br />• production data, e.g., pumping test data and/or airlift production data (collected during drilling) that indicate <br />parameters such as hydraulic conductivity, transmissivity, storativity, drawdown, etc. <br />Attachment A: SPLP results for Spot 5, 6" deep. <br />Comment: The Uranium concentration in the SPLP extract exceeds the drinking water standard for both ground <br />water and surface water. The Vanadium concentration exceeds the ground water agricultural standard. Gross Alpha <br />and Radium 226 exceed regulatory limits. Operator needs to report the Beta and Photon Emitters in terms of the <br />regulated units (mrem/yr), as shown on Table 1 of CDPHE Regulation 41. This may require speciation of the various <br />radionuclides present in the water sample, guidelines for which may be found in EPA document 816-F-00-002, <br />available online at: <br />http://www.epa.gov/ogwdwOOO/rad ion ucl ides/com plia ncehel p. htm I <br />Attachment C: Sample Analysis Results as Compared to Regulatory Thresholds <br />Comment: Applicant should reference the appropriate regulations: CDPHE Regulation 31 for surface water and <br />Regulation 41 for ground water. Operator must also be cognizant of the fact that La Sal Creek is a classified stream <br />segment per CDPHE Regulation 35.6(4), which can be found at: <br />http•//www cdphe state co us/regulations/wgccregs/100235wgccgunnisonlowerdoloresriverbaintables.pdf <br />Concentrations listed in Regulation 35.6(4) supersede those listed in Regulation 31. <br />Attachment J, Section 1.0: "The Summerville formation is viewed as an aquatard (sic) to any groundwater in the Salt <br />Wash." <br />Comment: Operator must provide a reference so that DRMS can verify the alleged hydrologic characteristics of the <br />units.