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Longwell subsidence and slope monitoring points were <br />installed and surveyed in the fourth quarter of 1984. The <br />location of these points and the advancement of the first <br />and second longwall panel are shown on the enclosed sap <br />entitled 8519-LS. The monuments have been surveyed on e <br />quarterly basis since the longwall production begin in May, <br />1985. The results from the first three surveys were <br />submitted and reviewed in January, 1986. The results of <br />the data obtained from the last two surveys are included in <br />this report. <br />Results from the June, 1985 survey showed no detectable sub- <br />aidence•took place. The results from the next three <br />surveys showed detectable subsidence as a result of the <br />first longwall panel being advanced 2,750 feet, these <br />results were included in the January report. <br />By the end of January 1986 the first longwall had been <br />completed and production on the second longwall began. At <br />the end of the first quarter (March 1986) the second long- <br />wall had been advanced 35 feet. At that time the first <br />subsidence along row S was detected. <br />In all rows accept R, subsidence has not increased, but <br />has decreased in the vertical direction as observed Yro^ <br />the June survey data compared with prior data. The maximum <br />subsidence for the affected rows in the June survey are as <br />follows: <br />6/86 <br />MONUMENT MAX. 1/86 <br />ROW NUMBER SUBSID. SUBSID. CHANGE COMMENT <br />--- ------ ------ ------- ------ ------- <br />H H-16 5.68 * 6.08 0.4 MOVED UP <br />S 5-17 4.96 * 0 -4.96 MOVED DN. <br />NPR R-9 4.82 * 5.13 0.31 MOVED UP <br />R R-12 5.74 * 6.11 0.37 MOVED UP <br />0 0-2 0.3 0.61 0.31 MOVED UP <br />* Indicate that was the station of maximum subsidence in <br />the January report. <br /> <br />