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Mr. Ed Baker March 17, 2005 Page 2 provided by NSL The width of the cavity is calculated by converting allocated tonnages to volumes using a rectangular cavity cross section and the nahcolite mining zones and nahcolite grades as described above. Two drill hole intersecfions of cavity lA have occurred. These provide an indication of the width of cavity lA near the projected location of 7H. In May 2002, NSI drilled Well SH. The horizontal drilling reached a total measured depth of 3,508 ft. The horizontal drilling lost circulation 67 ft from the projected well bore of cavity lA. The rectangulaz cavity model projected the edge of cavity lA at 74 ft using a 31.5-ft cavity height and at 48 ft using a 55.3-fr cavity height. In October 2002, NSI drilled Well 6H. The horizontal drilling lost circulation at a measured depth of 3,512 ft. This was a distance of 53.9 ft from the well bore of cavity lA. The rectangulaz cavity model projected the edge of cavity lA at 74 ft using a 31.5-ft cavity height and at 49 ft using a 55.3-ft cavity height. The uncertainties associated with the cavity shape estimation include: • Accuracy of tonnage allocation model • Actual height of the nahcolite zone that is being solution mined • Cross sectional shape of the actual solution mining cavity • Tons of nahcolite in solution within the cavity The tonnage allocation model assigns produced tons of nahcolite to locations along the length of the cavity based upon the relative leach rate of the fluid in the cavity. The injection fluid enters the cavity at a known concentration of nahcolite, gains concentration along the cavity as nahcolite is dissolved, and exits the cavity at or near saturated condition. The dissolution rate in the cavity is inversely proportional to the nahcolite concentration along the cavity. The allocation model is reasonable as indicated by the drill hole intersections. Unfortunately, limited data is available to validate its accuracy. An additional deficiency of the allocation model is that it does not account for the nahcolite that is dissolved but not produced. The cavity remains full of heat-saturated brine, which contains a significant tonnage of nahcolite. The cavity volume is larger by about 6%o to 9% to accommodate this dissolved but not produced nahcolite. The cavity width calculation is sensitive to the height of the nahcolite zone being solution mined and the cross sectional shape of the cavity. Early sonar measurements indicate that the cavity grows within the high-grade nahcolite zone of the Boies Bed until the cavity roof fractures and the cavity begins to grow vertically to the next confining layer. Operating experience indicates that cavity lA has connected to the Dissolution Surface. The uniformity of this connection is uncertain. There is a possibility that sections of the cavity may not achieve the full 55.3-ft cavity height. Upon this connection, NSI has demonstrated that solution mining can be continued with the cavity in equilibrium with the dissolution surface by cazefully monitoring dissolution surface monitoring well fluid levels and cavity pressures. Agapito Associates, Inc.