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• <br /> <br />The following table shows the relative change in each subsidence station, <br />from July, 1998 to November 1998. <br />Station Bearing <br />Distance Elevation <br />PL-1 N 24' 24' E 0.15 -0.08 <br />PL-2 N 30' 23' W 0.06 +0.01 <br />PL-3 N 48' 23' E 0.07 +0.02 <br />PL-4 N 08. 27' E 0.15 +0.02 <br />PL-5 S 05. 10' E 0.02 +0.18 <br />PL-8 S 01' 45' W 0.03 -0.11 <br />PL-7 S 17' 08' E 0.25 +1.03 <br /> ( PL-7 June 1997 -November 1998 ) <br />Sta 6 N 43. 01' W 0.05 -0.06 <br />Sta 14 N 48' 09' E 0.15 -0.03 <br />Sta 15 N 21. 30' W 0.24 -0.10 <br />Sta 16 N 20' 07' W 0.14 -0.14 <br />Station PL-7 was not surveyed in the November 1997 or in the June 1998 surveys. <br />Brush had grown up around the survey target making it difficult to see. A new traverse <br />station was established in November of 1998 to shoot PL-7 from another direction. <br />Relative change shown hen: for PL-7 is from June 1997 to November 1998. <br />In the process of conducting past surveys some stations had not been surveyed due to <br />a variety of factors. Some times, atmospheric conditions can be a problem, such as heat <br />waves that do not allow the distance meter to return a signal off of the target mirror. <br />Also some of the stations have had vegetation grow up between the target station and the <br />instrument station obstructing the view of the survey target. Weather can also restrict access. <br />Many of the points are only accessible by 4 wheel ATV, and if the trails become muddy <br />mobility is greatly reduced. <br />Changes in the coordinate values from survey to survey may be due to: <br />-Actual changes due to subsidence activity. <br />- Random errors inherent to any field survey. <br />If you have any questions please call. <br /> <br />Stephen B. Cragg <br />Bowie-l-subVan-99 <br />Page 13 <br />