2016-02-03_PERMIT FILE - C1981038A

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2.05 APPLICATION FOR PERMIT FOR SURFACE OR UNDERGROUND MINING ACTIVITIES B MINIMUM REQUIREMENTS FOR OPERATION AND RECLAMATION PLANS. 2.05.6 Mitigation of Surface Coal Mining Operation Impacts. (Cont'd) (6)(c)(i)(B) (Cont=d) a subsidence factor of 0.5 with respect to National Coal Board theoretical calculations. The Operator therefore believed that subsidence monitoring of these stations could be reduced to an annual basis and continued onlyto determine if any late term residual subsidence occurred within these grids. A technical revision (TR-6) submitted by the Operator in November 1988 and approved by the DMG commits the mine to annual surveying until the DRMS deems subsidence to be complete. The Operator further committed to reporting the findings on an annual basis. Correspondence from the DMG approving the monitoring program as revised by TR-06 was included in the Subsidence Appendix, Volume 3. Wide-spaced subsidence monuments were installed and surveyed prior to the commencement of mining in any new areas. Wide-spaced monument surveying continued on an annual basis until the sites were shown to be stable and approval to discontinue monitoring was obtained from the DRMS. In October, 1991 technical revision 16 was submitted to the DRMS by the Operator. TR 16 requested that subsidence monitoring be revised with respect to monument surveying. The Operator requested that surveying of the monuments over the inactive portions of the Orchard Valley Mine be discontinued. The request was based upon data generated during the 1989 and 1990 subsidence surveys which showed that the sites in question had continued to remain stable (refer to 1990 Annual Subsidence Report). The Operator concluded that continued periodic surveying to further investigate the potential for late term residual subsidence was unnecessary. During November, 2004, the Operator requested the suspension of subsidence monitoring on thirteen (13)wide spaced subsidence monuments, stations 14, 15, 16, 6, 81, 82, 83, 95, 99, D1+55, DH-65, DH-66 and DH-68. The Operator demonstrated the thirteen monuments have been stable since November, 2001, a period of three years, reference TR-45. During January, 2005, the DRMS approved TR-45, which discontinued all wide-spaced subsidence monitoring. As a result of TR-45, required subsidence monitoring was limited to the Pitkin Mesa Water line subsidence monuments, PL-1 through PL-7, which were monitored twice per year. The seven subsidence monuments were generally located over Panel C as shown on Map 2-5. Panel C was developed under the Pitkin Mesa Water line in 1992 and 1993. Panel C was not pillared. The Operator has demonstrated through its annual subsidence reports the seven Pitkin Mesa Water line subsidence monuments have remained stable since they were first monitored in 1992. Additionally, there have not been any problems with the Pitkin Mesa Water line in this area. The Pitkin Mesa Water line subsidence monuments will not be monitored after 2013. (Reference TR-57) (C) The orientation, location and elevation of each structure within the Revised 02/03/14 TR-57 147 �U Dved