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~: <br />SECOND-HALF 2004 SUBSIDENCE REPORT <br />I. Survey Data: <br />During the second-half of 2004, subsidence survey data was collected in early July 2004 <br />from established monuments on the Union Pacific Railroad (UPRR) in areas underlain by <br />gate roads or panel centers during periods of mining in the 16-Right (Panel No. 16) <br />longwall panel In early July, mining in the 16-Right panel was approximately 1500 past <br />the point on the railroad where [he longwall face/track intersects the tailgate entry. As <br />reflected in the data and on the attached subsidence map, the 16-Right longwall panel did <br />not directly undermine the Walcott, Hayden-Gore Pass, or Western Area Power <br />Administration power lines or Fish Creek during the second-half of 2004. <br />The data and frequency for the survey monuments along the UPRR are presented in the <br />attached Table No. 1. <br />II. Structures: <br />No structures were affected during the second-half of 2004 reporting period. As noted <br />above, in July 2004 mining in the 16-Right panel was approximately 1500 past the point <br />on the Union Pacific railroad where the longwall face/track intersects the tailgate entry. <br />Visual inspections of the Union Pacific Railroad by UPRR personnel were conducted <br />from May 5, 2004 through June 10, 2004. Daily surveys and observations of the UPRR <br />over Panel 16-Right were also performed by Twentymile Coal Company (TCC) personnel <br />from May 4, 2004 through July 7, 2004. Follow-up reports on the survey data and <br />observations were submitted to UPRR personnel on a daily basis. Final re-leveling of the <br />rail line to the post-mining target level will be performed by the UPRR in early summer <br />2005, as needed. A follow-up survey will be performed at that time and a final report, <br />reflecting final survey data, will be submitted to the UPRR. <br />Structures remained essentially unaffected during the reporting period, with the exception <br />of the predicted impacts to the Union Pacific Railroad and Fish Creek from first-half <br />2004 mining. No adverse impacts, i.e. imminent failure of structures, were evident with <br />regard to these structures. No repair work, beyond the future minor realignment noted <br />above, was required on the Union Pacific Railroad to address subsidence resulting from <br />TCC's mining activities. <br />III. Map: <br />The monitoring locations for the second half of 2004 are displayed on the Second-Half <br />2004, Subsidence Map. The map also indicates the location of the longwall face on a <br />monthly basis. <br />2004_2ndHalfSubReport.doc Page 1 of 3 03/01/05 <br />