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of preparing the Environmental Assessment for Emergency Coal <br />Lease C-29125. The fractures were observed in an area <br />approximately 300 feet north of the emergency lease boundary <br />• and on the east limb of Federal lease P-058300. The area of <br />possible subsidence is above the western edge of the pillars <br />that were extracted in the King Coal Mine in 1979. <br />The above evidence suggests that subsidence could occur due to <br />extraction of the 4.5 to 6-foot coal seam and pillars on <br />retreat in the application area. Although a maximum subsidence <br />of 6 feet could occur, the most likely showing on the surface <br />would be extension cracks such as the ones identified on <br />Federal lease P-058300. In addition, as a result of the <br />requirement for the quarterly monitoring of the area for <br />subsidence and the greater thickness of overburden, it is not <br />anticipated that subsidence will be evidenced to the degree <br />that was noted on Federal lease P-058300. <br />Subsidence fractures could allow the escape of methane gas to <br />the surface and could increase the hazard of underground and <br />surface fires. Although this is not likely due to the low <br />liberation of methane of the Menefee coal (less than 1$), the <br />potential of causing surface impacts is present. <br />Colorado Mined Land Reclamation Board (MRCS) rules 2.05.6 and <br />- 4.20 require that "underground-mining activities shall be <br />planned and conducted so as to prevent subsidence from causing <br />material damage to the surface...°. Material damage is defined <br />in Rule 2.05.6 with respect to subsidence as changes which <br />prevent restoration of affected structures and with respect to <br />• renewable resource lands; changes which disrupt an aquifer, or <br />a recharge area to an aquifer, which serves as a beneficial use <br />of water; or changes which prevent restoration of productivity <br />for agricultural lands. Implementation of these regulations <br />will minimize the impacts of subsidence. <br />WATER <br /> <br />The subject coal lease area would be above the potentiometric <br />surface (static water level) in the Menefee Formation, so that <br />only small isolated sandstone lenses containing groundwater may <br />be encountered during coal extraction. <br />Tension cracks resulting from overburden subsidence are <br />possible which could intercept an unquantifiable amount of <br />surface waters. <br />VEGETATION <br />Some minimal impacts to all vegetation would result if <br />subsidence occurs. <br />WILDLIFE <br />Since the proposed action is for subsurface mining, no direct <br />13 <br />