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2018 SUBSIDENCE SURVEY REPORT <br />I. Survey Data: <br />During the months of May through August 2018, subsidence survey data was collected <br />periodically from established monuments in open areas and on the Union Pacific Railroad <br />Energy Spur in areas underlain by panel centers during periods of mining in the 8 East <br />longwall panel. <br />The data and frequency for the survey monuments along the Union Pacific Railroad and <br />subsidence monitoring lines are presented in the attached Table Nos. 1 through 5. <br />II. Structures: <br />Structures affected during the 2018 reporting period include the Union Pacific Railroad <br />Energy Spur. <br />Daily surveys and observations of the Union Pacific Railroad (UPRR) over the 8 East <br />panel were performed from May 12, 2018 through August 8, 2018. A follow-up report on <br />the survey data and observations was submitted to various personnel from the UPRR on a <br />daily basis. It was suggested that re-leveling/raising of the track be performed <br />sequentially as mining progressed. To assist in the re -leveling process, Twentymile <br />supplied railroad tamping and ballast regulator equipment for railroad personnel use. <br />Partial re -leveling of the rail line to acceptable differential gradients by UPRR personnel <br />continued on a day-to-day basis through August 8, 2018. The rail line has been re -leveled <br />and raised to the post mining target elevation. A follow-up survey was performed in <br />August 2018. A final report was submitted to the UPRR subsequent to the survey. <br />III. May: <br />The monitoring locations for 2018 are shown on the attached subsidence map. <br />Monitoring locations included a long axis through the center of the 8 East panel, three <br />cross -axes, and stations 20+00 through 50+00 on the UPRR Energy Spur. <br />IV. Conclusions: <br />Subsidence monument surveys disclosed no unusual developments during the reporting <br />period. Subsidence magnitudes and projected draw angles were within the anticipated <br />ranges previously documented for the area. <br />Structures remained essentially unaffected during the period with the exception of the <br />predicted impacts to the Union Pacific Energy Spur. No adverse impacts, i.e. imminent <br />failure of structure, were evident with regard to the railroad. <br />Page 1 of 1 11/08/18 <br />