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Permit Revision Adequacy <br />July 6, 2004 <br />Page 17 of l8 <br />SOD mining, and the evaluation should include a quantitative worst case assessment of the <br />probable increase in specific conductance of waters in the North Fork downstream from the <br />mine workings dischazge azeas. <br />4.05.13 Surface and Groundwater Monitoring <br />117. Please add to the PAP a discussion of points of compliance for groundwater monitoring, as <br />found in Rule 4.05.13(b). This would include discussion of baseline groundwater quality, <br />groundwater quality after mining, potential and observed impacts to groundwater quality and <br />the potential for migration of any impacted water off the permit area. This could be done in <br />conjunction with the discussion on page 2.05-222 of the PAP, dealing with "protection of <br />hydrologic balance." <br />118. Regarding discussions among MCC, personnel from the State Engineer's Office, and the <br />Division, MCC must ensure that all monitoring devices, including flumes for measuring <br />surface water flow, are installed, maintained, and working properly. Please provide comments <br />to address the issue that was raised by the SEO personnel. <br />119. On page 2.04-51, proposed text states "Table 5 has been updated...and new monitoring wells <br />have been installed in SOD. A separate TR will be submitted to address the associated changes <br />in the hydrologic monitoring program." It would not be appropriate to approve SOD without <br />an acceptable hydrologic monitoring plan. Please incorporate a hydrologic monitoring plan for <br />SOD in PR-10. The plan should include details on the surface water monitoring plan, <br />describing how losses of flow in the Dry Fork of Minnesota Creek will be identified and <br />reported (as per Exhibit 52). <br />Rule 4.24 Operations in Alluvial Valley Floors <br />120. Rules 4.24.4(1)(b) and (c) require implementation of a monitoring system to demonstrate that <br />the essential hydrologic functions of alluvial valley floors not within the permit area aze <br />preserved during and after mining and that the operation is not causing material damage to <br />quantity or quality of water systems that supply identified alluvial valley floors. Rule 4.24.4(2) <br />requires that such monitoring be performed at adequate frequencies to indicate long term <br />trends. <br />For alluvial valley floors on the main stem and East Fork of Minnesota Creek, it would appear <br />that the only potential effect of mining would be to diminish the quantity of water supplied the <br />stream system, caused by dewatering associated with undermining of the Dry Fork, Lick Creek, <br />and the Deep Creek Ditch, and any other water supply ditches in the SOD permit extension <br />azea. For alluvial valley floors on the North Fork of the Gunnison River, potential effects <br />would include water quality as well as water quantity impacts. <br />Please include a summary of the hydrologic monitoring that will be conducted to comply with <br />the applicable requirements of Rule 4.24.4, within the Alluvial Valley Floor section of the <br />