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The following questions relate to the assessment of potential impacts to identified alluvial <br />valley floors and waters that supply the identified alluvial valley floors, associated with the <br />"E" seam mining plan within the proposed SOD permit extension area, pursuant to Rule <br />2.06.8(4). <br />6. Narrative in paragraph 3 on page 2.06.4 indicates that the operator will "...refine <br />the subsidence control plan for the mining area under Dry Fork" and further states <br />that an augmentation plan is being developed that "...when finalized, will detail <br />mitigation efforts for short and long term effects to water rights holders should <br />unforseen factors affect the hydrology of Dry Fork". This narrative appears to be <br />outdated. <br />a) Please update the narrative as appropriate to summarize the aspects of the <br />currently proposed SOD mining plan and subsidence control plan that will be <br />implemented to preserve the hydrologic balance of those portions of the Minnesota <br />Creek basin within the proposed permit area. Please include reference as <br />appropriate to detailed plans and designs in other sections of the application, <br />b) Please address the measures that will be implemented to prevent material damage <br />to the quantity of water in surface water systems that supply the alluvial valley <br />floors on Minnesota Creek. Please include, as appropriate, measures that will <br />prevent stream dewatering associated with undermining of the Dry Fork and its <br />tributaries, and Lick Creek, and measures to prevent damage to the Deep Creek <br />Ditch and any other water supply ditches that are located within the SOD permit <br />area. <br />c) Please update the status of the augmentation plan, and include reference to the <br />appropriate section of the application. <br />On amended page 2.04-143 there is revised language indicating that riparian <br />vegetation and wetlands in the SOD permit area extension would not be measurably <br />disturbed by underground mining. <br />Please address the measures that will be implemented to prevent dewatering of the <br />alluvial aquifer along Dry Creek associated with undermining. In addition, please <br />address the effect that ground surface lowering associated with longwall mining is <br />anticipated to have with respect to wetland water levels, and discuss the probable <br />associated changes in the extent and nature of wetland areas and wetland species <br />composition. <br />Rule 2.06.8(4)(a)liv) also requires submittal of information to demonstrate that the <br />operation would not materially damage the quality of water in surface or ground <br />water systems that supply identified alluvial valley floors. Please address within the <br />AVF section of the application, the potential for minewater discharge to affect water <br />quality suitability of waters used to irrigate the identified alluvial valley floors on the <br />North Fork of the Gunnison River. The assessment should be based on worst case <br />projection for both the short term (maximum discharge projected during operations) <br />and the long term (maximum discharge from flooded workings via designed <br />discharge and other connections between the flooded workings and the North Fork <br />stream/alluvial system). The projections should incorporate the effects of proposed <br />SOD mining, and the evaluation should include a quantitative worst case <br />assessment of the probable increase in specific conductance of waters in the North <br />Fork downstream from the mineworkings discharge areas. <br />5 <br />