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Railroad. The railroad (Colowyo and MCM railroad spurs) bed is located in the alluvial valleys of both the Yampa <br />and Williams Fork Rivers. The railroad bed is located outside the area of projected surface subsidence impact <br />resulting from the planned mining in the No. 5 and No. 6 Mines. Development mains and sub -mains were driven <br />under the railroad spur (see Map 24), however, sufficient pillars were left in place to provide adequate long-term <br />support and prevent or minimize subsidence. Standard approved methods, which stability analysis and past <br />experience show are adequate to prevent subsidence, were used. No longwall mining or pillar extraction has occurred <br />in this area and none is planned in the future. <br />Irrigation Ditches. The irrigation ditches are located on the alluvial valley floor and outside the area of projected <br />surface subsidence impact resulting from the planned mining of the No. 5 and No. 6 Mines. Therefore, mining - <br />induced subsidence will not affect the irrigation ditches. <br />RENEWABLE RESOURCE LANDS <br />Alluvial Vallpy Floors. The river valley bottoms of both the Yampa and Williams Fork Rivers are classified as <br />alluvial valley floors (AVF). Both the Yampa River AVF and the Williams Fork River AVF lie outside the area of <br />potential surface subsidence for any anticipated future mining. Development mains and sub -mains were previously <br />driven under both the Yampa River and Williams Fork River AVF's (see Map 24), however, sufficient pillars were <br />left in place to provide adequate long-term support and prevent or minimize subsidence. Standard approved methods, <br />which stability analysis and past experience show are adequate to prevent subsidence, were used. No longwall mining <br />or pillar extraction has occurred in this area and none is planned in the future. <br />Yampa River. The Yampa River is outside the area of influence for surface subsidence effects. Development mains <br />were previously driven under the Yampa River (see Map 24), however, sufficient pillars were left in place to provide <br />adequate long-term support and prevent or minimize subsidence. Standard approved methods, which stability analysis <br />and past experience show are adequate to prevent subsidence, were used. No longwall mining or pillar extraction has <br />occurred in this area and none is planned in the future. <br />Williams Fork River. The Williams Fork River is outside the area of influence for surface subsidence effects. <br />Development mains and sub -mains were previously driven under the Williams Fork River (see Map 24), however, <br />sufficient pillars were left in place to provide adequate long-term support and prevent or minimize subsidence. <br />Standard approved methods, which stability analysis and past experience show are adequate to prevent subsidence, <br />were used. No longwall mining or pillar extraction has occurred in this area and none is planned in the future. <br />Sandstone Aquifers. As discussed in Section 2.04.7, Hydrology Information, and addressed earlier in this section, the <br />sandstone units which are classified as aquifers do not serve as a "significant source" or even a minor source to the <br />TR14-36 2.05-53 Revised 06/23/14 <br />