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SECOND HALF 1997 SUBSIDENCE SURVEY REPORT I. Survey Data During the second half of 1997, subsidence survey data was collected periodically from established monuments on the Hayden -Gore Pass Power Line, and the Wolcott Tap - Wolcott Power Line in those areas underlain by gate roads or panel centers during periods of active longwall mining. Prisms were set on legs of the metal structures of the Hayden-Gore Pass power poles at S1, S2A, S2B, S2C, S2D, S3A, S3B, S3C, S3D and S4 and an initial survey performed on August 8, 1997. Daily surveys were conducted from August 9, 1997 through October 10, 1997. Weekly surveys were conducted from October 17, 1997 through the end of December, 1997. Table 1 provides a summary of the survey data collected for the first half of 1997. The Wolcott Tap -Wolcott survey data for the second half of 1997 are summarized in Table 2. Prisms were set on power poles at W4, W6, W6A, W8, W8A and W10 and initially surveyed on August 8, 1997. Daily surveys were conducted from August 9, 1997 through October 10, 1997. Weekly surveys were conducted from October 17,1997 through the end of December, 1997. Foidel Creek was surveyed, see figure 1, after the 8 Right Longwall Panel subsidence and the profile provided in the First Half 1997 Subsidence Report. Foidel Creek will be surveyed again in the Spring of 1998 to develop a profile of the creek showing the subsidence effects due to the mining of the 7 Right Longwall Panel. This profile will be included in the First Half 1998 Subsidence Report. II. Structures Structures affected during the second half 1997 reporting period include the Union Pacific Railroad track, the Hayden -Gore Pass power line, the Wolcott Tap -Wolcott power line, and the Western Area Power Administration power line, and Foidel Creek. The Union Pacific (UP) Railroad track visual inspections were conducted by UP maintenance personnel from July 30, 1997 through September 10, 1997 for the second half of 1997. The maintenance work performed during the period of subsidence included placement of additional ballast on an as needed basis, and releveling the track with a production tamper. All of the maintenance work was performed by UP personnel. The Hayden -Gore Pass line, Wolcott Tap -Wolcott line, and Western Area Power Administration line daily visual inspections were conducted concurrent with the survey of the power poles from August 8, 1997 through October 10, 1997. Limited damage occurred to the Hayden -Gore Pass structure, however, utility representatives inspected