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<br />XXI. Sealing of Drill Holes and Underground Openings - Rules 2.05.4(2)(8) and 4.07 <br />Information pertaining to the sealing of drill holes and portal and ventilation <br />openings is presented in Section 2.05.4 of the permit application. <br />All portal and ventilation entries will he permanently sealed by backfilling each <br />opening with underground development waste, common fill, and sediment from the <br />two sediment ponds fora distance of 50 feet from the entrance. Once backfilling <br />is completed, each entry will be collapsed with explosives. National <br />Y.ing Coal has adequately demonstrated that sufficient quantities of fill material <br />exist on site to complete both portal and mine bench backfilling activities. <br />A single drill hole currently exists at the mine site in Hay Gulch and is used as <br />a water well. The landowner has requested that this well remain open following <br />permanent cessation of operation. The Division previously agreed with this <br />request and hereby reaffirms this previous approval. Therefore, the drill hole <br />is not required to be sealed. <br />The operation is in compliance with the requirements of this section. <br />XXII. Subsidence - Rules 2.05.6(6) and 4.20 <br />Information pertaining to subsidence is presented in Section 2.05.6 (pages 15-20) <br />of the permit application. <br />National King Coal has demonstrated that one structure and a potential renewable <br />resource area exist within the permit area. The structure, known as the <br />Huntington Irrigation Ditch, acts as an overland conveyance for water used for <br />downstream irrigation. This ditch overlies portions of the King Coal Mine. <br />Field observations indicate that surface subsidence features are present above <br />abandoned portions of the mine. National King Coal conducts quarterly subsidence <br />investigations and ditch inspections. The ditch inspections have not indicated <br />the presence of visible fractures, nor have they indicated that water is being <br />lost to the mine via surface fracturing. <br />The field subsidence surveys indicate that there has been minimal vertical or <br />horizontal movement of the established subsidence monuments. The quarterly <br />subsidence survey at the King Coal Mine will continue during the second permit <br />term. <br />The owner of the irrigation ditch has reached an agreement with National King <br />Coal, which grants the company the right to effect necessary repairs to the <br />irrigation ditch, should it be affected by subsidence processes. <br />The potential renewable resource area is the Pine Gulch drainage in the south <br />eastern portion of the permit area. In order to avoid impacting the Pine Gulch <br />stream, National King Coal has committed to not extracting coal from beneath this <br />drainage. <br />The operator will continue to monitor the established subsidence monuments with a <br />semi-annual field survey, quarterly visual inspections and quarterly ditch <br />inspections. <br />Tire operation is in compliance with the requirements of this section. <br />-23- <br />