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AGAPITO ASSOCIATES, INC. CONSULTING ENGINEERS ,\ ~~ / May 1, 2003 / Ed Baker Natural Soda, Inc. 3200 County Road #31 Rifle, CO 81650 13E~'"'',' ~-~ . ~. M;;f „ 5, ....~ Divts(an of Minerals anA Geota~y GRAND JUNCTION OFFICE 134-25 RE: Preliminary Summary of TDR Installation and Performance Dear Ed: This letter presents a summazy of the installation of the four-cable TDR subsidence monitoring well and the results of the data from those four installations. The TDR installation began on April 16, 2003, and was completed on April 17, 2003, after several days of drilling to complete the borehole. The readings from all four of the cables on April 17`h, after grouting the lower 180 ft of the hole, presented data that indicated the cables were functioning properly, as indicated by strong end-of--cable reflections. Readings taken on Monday (4/21/03) indicated that three of the four cables had been compromised, such that the end of the cable was no longer "visible." Data from one cable, TDR3, indicated that it was functioning properly, with crimps and the cable end visible. INSTALLATION The four TDR cables were attached to a 200-ft-long string of 1'/z-inch Schedule 80 PVC pipe by use of a pneumatic banding tool. The PVC string was attached to AQ wireline steel drill rod that was dewupled using a reverse thread connection, The TDR cables that were installed are Commscope 0.875-inch-diameter, solid aluminum outer conductor with a copper clad aluminum inner conductor. The cable dielectric is a high- compression microcellulaz foam The cable has a polyethylene jacket. The cable impedance is 75 t 2 ohms. The propagation velocity coefficient is 0.87, with respect to the speed of light. The TDR cables were installed at 20-ft intervals. The base of TDRI was installed at 1823 ft below ground surface (bgs). The base of TDR2 was installed at 1803 ft bgs, The base of TDR3 was installed at 1783 ft bgs. The base of TDR4 was installed at 1763 $bgs. Each cable had reference crimps placed at 50-ft intervals from the bottom of each casing up to the level of the B-Groove at 1589 ft bgs. Crimps were placed in all four cables at a depth coincident with the B-Groove. Figure 1 is an as-built drawing of the TDR monitoring well.