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FIRST HALF 2002 SUBSIDENCE SURVEY REPORT <br />I. Survey Data• <br />During the first half of 2002, subsidence survey data was collected periodically from <br />established monuments on the Union Pacific Railroad and the YVEA power line in areas <br />underlain by gate roads or panel centers during periods of mining in the 13-Right (Panel <br />No. 13) longwall panels. As is reflected in the data and on the attached subsidence map, <br />the 13-Right longwall panel did not directly undermine the Walcott, Hayden-Gore Pass <br />and Western Area Power Administration power lines, and Foidel Creek during the first <br />half of 2002. <br />The data and frequency for the survey monuments along the Union Pacific Railroad and <br />the YVEA power line are presented in the attached Table Nos. 1 and 2. The post mining <br />survey of Fish Creek in areas underlain by the 13 Right gate road or panel center was <br />performed in July/August 2002. The final subsidence profile for Fish Creek over Panel <br />13 Right is submitted with this second half 2002-subsidence report. <br />II. Structures• <br />Structures affected during the first half of 2002 reporting period include the Union Pacific <br />Railroad and the YVEA power line. <br />Visual inspections of the Union Pacific Railroad and the YVEA power line were <br />conducted from December 14, 2001 through April 3, 2002. <br />Daily surveys and observations of the Union Pacific Railroad (UPRR) over Panel 13 <br />Right were performed from December 26, 2001 through April 3, 2002. A follow-up <br />report on the survey data and observations was submitted to vazious personnel from the <br />UPRR on a daily basis. Apre-miming "humping" of the railroad track with ballast was <br />performed in October 2001, prior to undermining of the track in January 2002. Final re- <br />leveling of the rail line to the post-mining tazget level will be performed by the UPRR in <br />the late summer 2002 as needed. A follow-up survey will be performed at that time. A <br />final report will be submitted to the UPRR subsequent to these surveys. <br />Visual observations of the YVEA power line from December 14, 2001 through the last <br />weekly survey on February 2, 2002 did not indicate any noticeable change. No repair <br />work was required to this power line as a result of TCC's mining activity. <br />III. Map; <br />The monitoring locations for the first half of 2002 are shown on the First Half of 2002, <br />Subsidence Map. The map also indicates the location of the longwall face on a monthly <br />basis. <br />2002_1stHalfSubReport Page 1 oft 09/03/02 <br />