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Mr. Bryce Romig <br />May 29, 2001 <br />Page 2 <br />c. If the movement monument surveys conducted in the spring of 1998 indicate that <br />no movement or nominal movement is occurring, CMC will continue to survey <br />the monuments semiannually for 2 additional years, with results reported in the <br />CMC annual reclamation report. If, at the conclusion of this monitoring period, <br />no problematic movement has occurred, the movement monuments may be <br />abandoned. <br />Western States Surveying, of Parker, Colorado, conducted the necessary surveying, and the <br />survey data are presented in Table 1. The remainder of this letter summarizes Exponent's <br />evaluation of the survey data. <br />Evaluation of Survey Data <br />Table 1 presents the survey data collected to meet the requirements set forth by DMG. Also <br />presented in Table 1 are the deviations in subsequent surveys from the original survey points. <br />As can be seen from this data, no monument moved the 0.2 feet referenced in item b above. In <br />fact, no monument moved more than 0.082 feet (this equals 0.98 inches) in any one direction. <br />The accuracy of the survey was reported by the surveyor to be ±0.05 feet in the horizontal <br />direction (i.e., northings and eastings), and ±0.02 feet in the vertical direction (i.e., elevation). <br />With this understanding of the survey's accuracy, the survey results were plotted to represent <br />the variations in subsequent surveys from the initial survey. The accuracy of the survey was <br />shown by error bars on the individual data points, and lines showing the maximum and <br />minimum location of the original survey point. Figures 1, 2, and 3 present this data for the <br />northings, eastings, and elevations, respectively. <br />From these figures, the following can be determined: <br />No movement monument was observed to move greater than 0.082 feet ±0.05 <br />feet for the period of record. Therefore, no movement of greater than 0.2 feet <br />was observed during the spring filling in 1998 (as discussed in item b, <br />above), or in any subsequent surveys. <br />Except for two elevation points for Monitoring Monument 13, the surveying <br />error of all subsequent surveys for each movement monument falls within the <br />error of the original survey, and therefore, the monuments may not be <br />moving at all. <br />' Albrick, C. 2001. Personal communication (telephone conversation with M. Martin, Exponent, Boulder, CO), <br />Western States Surveying. <br />66019aZ0020101 O60t MMO1 H /V <br />