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t: <br /> electronic distance measuring device (EDM). at` <br /> The method of the monitoring surveys Involved side shots from the <br /> established control polntslto the monitoring points. Horl_zontal and vertical <br /> angles were measured in both the erect and inverted aspects. Slope distance was <br /> Jv <br /> determined to the nearest 0.01 ft by taking the average of three EDM readings. <br /> ,x~ 4.0 RESULTS <br /> , . The results of the control survey are tabulated to Table 4.0-1 as ;• ' <br /> coordinates and elevations of the TP-serles control points. The results of the <br /> monitoring surveys are tabulated in Tables 4.0-2, 4.0-3 and 4.0-4 as coordinates ' <br /> and elevations for the MC-serles monitoring points for the 1981, 1982 and 1983 <br /> surveys, respectively. <br /> 5.0 CONCLUSIONS <br /> ' Table 5.0-I presents he changes In elevations for each MC-series monitoring <br /> point as a function of time. The determination of subsidence was based on a .A <br /> negative change in elevation of more than 0.1 ft. This value of 0.1 ft was ` <br /> determined from the vertical angle accuracy requirements of a Third Order, Class` •` <br /> 11 survey. This standard indicates a maximum allowable spread of 20 seconds { _ <br /> between vertical angle ob ervations of the same point. Based on an average #; <br /> horizontal distance of 2950 -ft for the eight closest monitoring points, this " <br /> equates to a maximum variation In the calculated change in elevation of 0.1 ft. <br /> Monitoring point MC#1 was excluded from the average horizontal distance n <br /> t,M <br /> calculation because the magnitude of its horizontal distance was about 2000 ft <br /> greater than that of the next longest horizontal distance. Inclusion of the <br /> horizontal distance for KVI would yield an acceptable spread of 0.12 ft in the <br /> 3 <br />