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Doc Date:12/11/2001 III I II I II I II IIII III sss _~ SECOND HALF 1995 SUBSIDENCE SURVEY REPORT I. Survey Data During the second half of 1995, subsidence survey data was collected periodically from established monuments on Routt County Road 27 in those areas underlain by gate roads or panel centers during periods of active mining (refer to Figure 1 for monument locations). Table 1 provides a summary of the collected data for stations R1- R6 located over the gate roads at the west end of the 1 Southwest longwall panel undermined in July 1994; for station R7 situated over the center of the 1 Southwest longwall panel undermined in August 1994; for stations R8-R15 located over the gate roads on [he south side of the 1 Southwest longwall panel undermined by the 1 Southwest longwall panel in September 1994 and the 2 Southwest longwall panel in March 1995; for station R16 situated over the center of the 2 Southwest longwall panel undermined in March 1995; for stations R17-R20 located over the gate roads on the south side of the 2 Southwest longwall panel undermined by the 2 Southwest longwall panel in March 1995 and the 3 Southwest longwall panel in November 1995; and for station R-21 situated over the center of the 3 Southwest longwall panel undermined in November 1995. During the second half of 1995, monitoring of County Road sites associated with the 2 and 3 Southwest longwall panels was completed. • Sites R22-R25 located over the gate roads on the south side of the 3 Southwest longwall panel undermined in November 1995 were destroyed during construction of the trench berm sandstone cliff mitigation project. Data from stations E10, E11, and E12 associated with the YVEA powerline is provided in this report along with data from sandstone cliff monitoring stations C1-C8. Additional survey information for the Fish Creek AVF 5000 line consisting of six points established to verify that subsidence resulting from the mining of the 2 Southwest longwall panel in December 1994 does not extend into the Fish Creek AVF is also presented in this report. The 5000 line survey monument locations are depicted on Map 23A. II. Maps Monument locations are depicted on Figure #1 and Map 23A. The extent and sequence of underground development during the period is presented as the Twentymile Coal Company - Foidel Creek Mine monthly update map for the period ending 12/31/95. The I Southwest longwall panel was initiated in July 94 and completed in December 94. The Southwest longwall panel was initiated in December 95 and completed in June 95. The 3 Southwest longwall panel was initiated in July 1995 and neazly completed in • December 1995 as shown on the monthly update map. Segments of Routt County Road 27, the Twentymile Sandstone rock outcrop, and the 1'VEA power Line undermined during the second half 199 reporting period are shown on