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On April 26, 1988, EC submitted the required subsidence monitoring report to the CDMG. Attached to this report
<br />was a cover letter, which requested the CDMG to advise if the monitoring program could be discontinued. The
<br />CDMG, through its letter of August 30, 1988, recommended that the monitoring program be discontinued for the EC
<br />Mine. To formalize this, Technical Revision 12, which requested discontinuation of the No. 5 Mine Subsidence
<br />Monitoring Program, was submitted to the CDMG on September 9, 1988 and approved November 1, 1988.
<br />As noted in Mr. Pendleton's memorandum of August 26, 1988, on this topic, the subsidence monuments will be left in
<br />place in case future survey work is required.
<br />Details of the No. 6 Mine, "E" Seam, Subsidence Monitoring Program can be found in a letter to the CDMG dated
<br />April 20, 1990. Anthony Waldron and Jim Pendleton determined that this was a clarification only and that a revision
<br />to the permit was not necessary.
<br />In association with Technical Revision 19 (No. 6 Mine mains and submains under Highway 13 and the Williams Fork
<br />River), EC installed and performed a one-time survey of three (3) subsidence monitoring points H-1, H-2 and H-3,
<br />which are shown on Map 31.
<br />Elimination and Suspension of Subsidence Monitoring
<br />EC has been conducting subsidence monitoring since it began mining in the No. 5 Mine (D Seam). Originally, the
<br />monitoring network was established to record actual versus predicted subsidence over room and pillar areas. The
<br />monument associated with this work was positioned on monitoring rows A, B, C, and D. A longwall was installed in
<br />the No. 5 Mine and monitoring lines were set up over panels 12 East, 13 East, and 14 East. The CDMG approved the
<br />discontinuance of subsidence monitoring at the No. 5 Mine on November 1, 1988.
<br />Since the completion of mining at the No. 5 Mine, EC has continued its operations into the No. 6 Mine (E Seam). A
<br />monitoring network was established to verify subsidence predictions; this network has served the mine well. The
<br />network was established to measure subsidence over both previously subsided areas and new areas to be subsided.
<br />Additionally, points were established over the north mines in the No. 6 Mine to measure subsidence along Highway
<br />13 and the Williams Fork River. Specifically, the reader is referred to lines A, B, C, D, H, J, S, and R for location of
<br />the No. 6 Mine monuments.
<br />EC monitored these points until September 1997. Based upon the 1996 monitoring program, EC requested and the
<br />CDMG approved, the:
<br />• Elimination of monitoring points located on lines A, B, C, D, and S; and
<br />• Suspension of monitoring points located on line J, points Hl -H3, and RI — R3
<br />The monuments for lines A, B, C, D and S will be lef
<br />reclamation plan. The monuments on line J and points Hl
<br />authorized by the CDMG.
<br />SUBSIDENCE SURVEY
<br />in place or removed in accordance with the approved
<br />— H3 and RI — R3 are to remain in place until removal is
<br />EC has determined that the worst possible consequences of subsidence will not result in any material damage or
<br />diminution of reasonable foreseeable use to structures and renewable resource lands within and adjacent to the permit
<br />area. However, some subsidence damage may possibly occur to some of the structures and renewable resource lands
<br />identified in Table 78, Inventory of Structures and Renewable Resource Lands. Therefore, to adequately assess the
<br />impacts of planned mining; EC has prepared the following subsidence survey.
<br />EC believes that the subsidence prediction prepared for this permit is a conservative estimate of the potential
<br />Permit Revision 04-34 2.05-55 Revised 7/2/04
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