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results of the monitoring program at least semi-annually. Maximum total <br />subsidence of 10 feet has been reported in the subsidence reports. <br />T'he longwall panel 2 of Mine 6 was proposed to undermine the Amoco pipeline. <br />T'he predicted subsidence that could occur under this zone was estimated at 10.5 <br />fee[, since this would involve one longwall panel under room-and-pillar workings. <br />ht lit:u of subsiding the pipeline, the operator opted to relocate the pipeline and not <br />conduct full extraction of the coal within L00 feet horizontally of the pipeline. This <br />100-foot buffer will allow for an angle of draw calculated at 19°. This plan was in <br />agreement with the Amoco Pipeline Company and approved by the Division by <br />Minor Revision No. 23. Amoco maintains a pressure monitor that would alert the <br />pipeline company of any disruption in the line. Should a disruption occur, action <br />will be initiated to locate and repair the ruptured line. <br />The operator also submitted a plan to undermine a portion of the railroad spur, the <br />Williams Fork alluvial valley floor, the Williams Fork River, and a portion of State <br />Highway 13. Further detail on this proposal can be located in Technical Revision <br />No. 19. The Division approved of development mining only under these resources, <br />with ehree additional subsidence monitoring locations along the highway, <br />'Che Division has previously found the pemuttee's subsidence control plan <br />t:otnplies with Rule 2.05.6(6) and the permittee has committed to adopt all <br />measures in order to reduce the likelihood of subsidence, prevent material <br />damage, or mitigate the effects. The Division has previously approved the <br />plan (4.20.1(2) and 4.20.3(1)). <br />2. The Division has previously found that the permittee's subsidence monitoring <br />program complies with Rule 2.05.6(6)(c), and is designed to determine.the <br />commencement and magnitude of subsidence movements. The "E Seam <br />L.ongwall Subsidence Monitors" map submitted with the semi-annual <br />subsidence report depicts the location of monuments to be installed and <br />structures to be monitored within the permit and adjacent area. The results of <br />the monitoring program will be submitted to the Division semi-annually. The <br />monitoring program is designed to extend for a time, beyond cessation of <br />mining in any area, consistent with the need for verification of the subsidence <br />prediction. <br />XI. Operations on Alluvial Valley Floors <br />The applicant has determined that alluvial valley floors exist along both the Yampa and <br />the Williams Fork valleys within the permit and adjacent area. This determination is <br />based upon the fact that flood-irrigated agricultural activities are practiced on <br />unconsolidated streamlaid deposits along both rivers. The Division concurs with this <br />determination. The boundary of the alluvial valley floors is shown on Map 25 of the <br />permit application. Three alluvial valley floors have been identified; [he Williams Fork <br />34 <br />