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Post Grout Crimp Elevations remaining are: 32.94' 424.21' 819.49' 97.53' 490.09' 885.10' 163.53' 556.01' 950.07' 229.6' 622.05' 1000.00' Short in cable 295.14' 687.69' 359.85' 753.56' A reading taken on July 1, 2004 showed the crimp elevations to be the same as the June 17, 2004 readings. A slight change in the waveform was detected between the Pre Grout and Post Grout readings taken on June 17, 2004. The waveform did not vary between the Post Grout reading on June 17, 2004 and the Post Grout reading on July 1, 2004. The elevations remained the same in all readings. The readings on September 2, 2004 show the crimp elevations are the same but the Waveforms are reduced by as much as .05 units at the 950.07' elevation with a lesser reduction at each ascending elevation up to elevation 295.14' where the Waveforms match the previous readings. The instrument used to read the TDR cable was calibrated and a diode was replaced prior to the December 16, 2004 readings. This change in the instrument might explain the drift in the Waveform readings of earlier tests. The December 16, 2004 readings show the same crimp elevations as all earlier readings but the Waveforms less than .01 between elevation 950.07' and 32.94' where all of the earlier readings had shown a nonlinear increase of approximately .08 units from elevation 950.07' to 32.94' for the June 17 and July 1, 2004 tests and approximately .13 units for the September 2, 2004 test. If the next quarterly readings of the TDR cable duplicate the Waveforms of the December 16, 2004 readings that should confirm that the Waveform variations were from a weakening diode in the instrument. The TDR data gathered on March 9, 2005 is basically identical to the data from December 16, 2004. There are no indications of ground movement at well 20-12. Since many of the welts in the lower well field including weft 20-12 have been plugged American Soda has reclaimed the surface area on and around the plugged wells. Gamba and Associates has surveyed points around well 20-12 to establish new surface elevations. These measurements have been compared to aerial surveys of this site and the findings are that within the accuracy of the aerials which is plus or minus 1 foot and the elevation difference of any given location was less than 0.6 ft., there is no indication of surface subsidence. The newly established ground elevations will be used for comparison with future measurements for subsidence monitoring. Attached with this letter are the following documents: Graphs of TDR Cable readings for Well 20-12 from 6-17- 04, 7-01-04, 9-02-04, 12-16-04 and 3-09-05. Agapito Associates Inc. March 11, 2005 communication verifying March 9, 2005 TDR Readings on Well 20-12. Gamba & Associates April 7, 2005 communication verifying the accuracy of the field survey of surface elevations around Well 20-12. Gamba & Associates April 7, 2005 communication identifying the Excel spread sheet showing three general areas of surface measurements around Well 20-12. Spread sheet showing elevation readings from Areas 1, 2, and 3 at Well 20-12.