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. Station 83 Grosse-Rhode Ranch Site. This station was created in 1996 by 1JTE Engineering and Surveying Company to replace previous Station 97. Discrepancies concerning stations 94. 96, 97 and 98 requved new stations to be established. No survey data was reported for this site during 1998. Pitkin Mesa Pipeline Seven subsidence monitoring stations were established at locations along the Firkin Mesa Pipeline which overlies Panel C. Panel C development commenced in October with twenty-four crosscuts completed by January 1, 1993. Panel C was mined utilizing a partial extraction design intended to preclude the development of subsidence in order to protect the pipeline. The subsidence monitoring stations along the pipeline are depicted on Map No. 2-SA. The stations were surveyed twice in 1998; July l0 and November 23. The resuks of these surveys are appended to this report. The 1998 survey was conducted by Cragg Surveying. The Cragg survey will provide consistent survey values in the future which will show that this area is stable. Surveys will continue approximately semi-annually until stability is documented. Visual Monitoring 1997 Visual subsidence monitoring is accomplished by periodic `tivalkovers" of recently mined areas within the present permit area. Walkovers are generally done in conjunction with survey monitoring due to the seasonal accessibility of the area. Visuai monitoring is concentrated over areas of retreat mining with particular emphasis on areas mined under low overburden. . A visual subsidence monitoring inspection was conducted the second week of July 1998. Panel Y and II West Submains were inspected. IV South Submains and III West Submains were not mined on retreat and were therefore not inspected. Projected Subsidence Impacts - 1999 Subsidence impacts during 1999 are projected to be minimal based upon subsidence pattertis established to date. No mining is currently projected for 1999. Projected Subsidence Monitoring - ]999 Per the conditions of Technical Revision 16, the operator is required to inform the Division of selected sites proposed for stuveying for the upcoming year. For the calendar 1998 year, the operator proposes the following thirteen (13) sites for surveying (see Map No. 2-5 appended to this report): 6, 14, 15, 16, 88, 89, 90, 90 and 95; Drill hole location 55, 65, 66 and 68; structure locations in the north'/: of Section 10 which will be denoted subsidence monitoring points 81, 82 and 83; and the comer of Sections 9, ] 0, 15 and 16 designated as point 99. These sites will be surveyed once during the year. In addition, the operator will survey the seven (7) Firkin Mesa Pipeline monitoring locations sem- annually until stability is documented. • -4-