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Probable Hydrologic Consequences of the Eagle Mines The Eagle Mines are located in a hydrologically aensit:ive area; Chere are four rock aquifers and two stream/alluvial systems that- can potentially be affected by mining. Underground mining in these mines creates the potential for depleting the quantity of water in the four rock aquifers, the two alluvial bodies, and the Yampa and Williams Fox-k Rivers. There is also a potential for water quality degradations in the rock aquifers, alluvial bodies, and the rivers. This section is a die:cussion of predicted and observed impacts of underground mining in the Eagls: No. 5 and 6 Mines to the hydrologic regime. The mining which would generate the major hydrologic impacts from the Eagle No. 5 Mine has already occurred. There will be no additional mining beneath the level of the stream/alluvial systems of the Yampa and Williams Fork Rivers. The mine ie currently progressing downdip toward the Yampa and Williams Fork stream/alluvial systems in the Big Bottom Synclinal Basin and above the level of the stream/alluvial systems of the Yampa and Williams Fork Rivera. Mining of development mains under the Williams Fork River has been approved with technical revision No. 19 and will likely occur within the upcoming permit term.. This approval dies not allow for coal extraction beyond development mining. Some depletions from the rock aquifers and stream/alluv.ial systems are expected but, ae discussed below, these depletions +ire not considered significant. Mine water discharge is expected to affect surface water quality, but not to the extent that water use would be limited. Assuming the portals are properly sealed, the long-term water quality impacts to surface waters will be minimal. The monitoring plan contained in the permit application has been designed to verify the applicant's projected hydrologic impacts of mining. 15