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2) In the area of the 3rd South Mains, the railroad is at an elevation of approximately 6,140' amsl and the F-Seam is at about 5,750' amsl, so the intervening overburden is roughly 400' thick. The massive Middle Sandstone is approximately 100' thick in this area and lies approximately 80' above the F-Seam. Given that mining of the F-Seam under the proposed liability release area occurred during the early 1970's through mid 1980's, much of this mining was pre-law. The existing approved permit addresses those activities that occurred subsequent to passage of SMCRA and the interim regulatory period, as well as anticipated future mining activities. Section 2.05.6(6) of the PAP provides specific discussions and plans for subsidence monitoring, surveys, a subsidence control plan. These discussions specifically include information on subsidence control and monitoring for the rail-line with respect to planned and future mining activities. Historic underground mine workings in the general vicinity of the cell tower and communications structure are probably pre-law. In addition, these structures do not overlie historic mine workings, and the potential for subsidence effects is negligible given that the nearby mining was limited to advance room and pillar mining with retention of the supporting pillars on retreat, and overburden thicknesses in this area exceed 700', including four massive sandstone units (the Middle Sandstone, Twentymile Sandstone, and two others, totaling over 300' in combined thickness). Access roads in the mine area are not a concern relative to subsidence control, monitoring, and mitigation, for the same reasons outlined above, because most of the roads are oevned and used by BTU Empire, and because the access roads are light-use roads that can be readily repaired if affected by subsidence to maintain effective access (no repair work has been necessary in the approximately 10-years since active mining operations ceased or in the approximately 20- to 30-years following completion of mining in this area). 20. Dewatering of underground mine workings, the treatment acrd discharging of water generated from mine dewatering, and the operation and maintenance of equipment and facilities associated with mine dewatering are activities over which the Division exercises regulatory authority. The Division cmtnot approve final liabt~lity release or Phase 117 bond release for activities within its jurisdiction that continue to occur at the time a fi~ral liability release or Phase III bond release request is submitted. Ongoing dewatering may present water quality and subsidence impact effects that differ from the water quality and subsidence impacts expected once dewatering ceases. As such, the Division may not be able to approve this final liability release or Phase III bond release request in areas where mine dewatering activities are actively occurring. Please discuss therefore, wDzether the mine workings that lie beneatlr The areas subject to this bond release request are currently being dewaterec~ and whether the water being generated from t/zis dewatering is being treated and disc{urrged Please also address the issue of long term water quality and sr~bsidence impacts when pumping ceases, relative to current conditions. Response: Please refer to the previous responses to Comments 12, 13, and 16. The area addressed by the proposed liability release is well above the active dewatering horizon and is, therefore, not directly affected by ongoing dewatering activities. Long-term hydrologic and subsidence impacts are addressed in the PAP by the discussions of Probable Hydrologic Consequences (Section 2.05.6(5)) and Subsidence Monitoring, Subsidence Survey, and Subsidence Control Plan (Section 2.05.6(6)). •As noted in the previous response to Comment 19, subsidence discussions do not directly address this area, given it's pre-law status, however, the general discussion of mining-related subsidence effects is applicable. It is important to note that in the approximately 20-30 years since mining was completed in Liability Release Response - No. 3 3 12/07/05