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(~ Monitoring of established monuments and structures shall be performed at • leas[~c uarterly, commencing one month prior to the initiation of mining beneath anv established monument or structure. least semi-annually. (E) Results of the monitoring program shall be submitted to [he Division at (F) The monitoring program shall be designed to extend for a time, beyond cessation of mining an anv area, consistent with the need for verification of [he subsidence prediction. (ii) The application shall include an appropriate map, prepared according to [he standards of Section 2.10, showing the location of monuments to he installed and structures to be monitored within the permit and adiacen[ area. RESPONSE Prior to panel development below the Twentymile Sandstone, a subsidence monitoring program will be initiated to provide quantitative data regarding potential subsidence above underground workings. Monuments will be installed [o a depth below the frost line, to avoid frost heave damage, and shall be constructed to an approved standard. The location of monuments are shown on the five year mine plan map, Map 23A. The monuments have been designed to fulfill the following requirements: Above Main Entries • Monuments have been installed at 100 foot intervals along the center line of the main entries in the location of Foidel Creek. _ The data gathered from the subsidence network installed over the main entries along Foidel Creek demonstrates that subsidence has no[ occurred in [his area. Because of this, monuments FC-?, FC-3 and FC-4 have been deleted from the subsidence monitoring plan. Since subsidence has not occurred within the Foidel Creek Area, TCC does not intend to establish monuments over main entries which will be driven under Fish Creek. 2. Above Production Panels In reference to Ist Panel South, hvo lines of monuments have been installed as shown on Map 23A, Five Year Mine Plan. The maximum spacing between adjacent monuments in the same line is 100 feet or approximately 10% of the overburden depth. Spacing has been narrowed to 50 feet on the east side of the panel to better define the angle of draw. One line will be along the centerline parallel to the long axis of the panel. A second line will be transverse [o the long axis of the panel. The lines will extend beyond the panel area to fully cover the area within [he maximum possible angle of draw. The steep cliffs formed by [he Twentymile Sandstone may make some sites inaccessible. As indicated by the semi-annual monitoring extraction area of I st Panel South. However. since the extent of subsidence has stabilized, these monuments (SM-7 through SM-41, inclusive) will be deleted . from the monitoring plan as of 1st quarter, 1989.