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A complete wireline logging program, including natural gamma, casing integrity and <br />cement bond, with comparison to baseline will be conducted prior to plugging a <br />production well as long as nahcolite recovery has exceeded 50,000 tons. <br />3.0 Subsurface Monitoring (cavity and pillar interval) <br />Prior to drilling production wells, a monitoring well will be drilled into the center of the <br />pillar formed by the initial three production wells. This monitoring well, DSW -1, will be <br />drilled to a depth below the proposed mining depth, and a steel casing cemented into <br />place. The casing will be perforated in the 40 or 50 feet just above the Dissolution <br />Surface. This DSW -1 will serve both as a water quality monitoring well and as access <br />for down -hole geophysical data collection. <br />The purpose of the cavity and pillar interval subsidence monitoring is to provide feed <br />back to advance solution mining technology and gain mining process control of potential <br />impacts to the overlying fresh water aquifers and oil shale resource. Total and sectional <br />cavity volume will be determined from production data and fluid pad displacement <br />results. Comparisons to baseline cross borehole tomography from within DSW -1 in the <br />pillar to each production well will provide an indication of each pillar — cavity profile, <br />each cavity void volume, and the condition of the oil shale debris in each cavity. <br />Comparison to baseline wireline natural gamma, temperature, casing integrity and cement <br />integrity logging will provide information on the pillar condition and subsidence. <br />AmerAlia will evaluate improved technologies and methods to characterize the nahcolite <br />solution cavity and present the findings to DMG, BLM and EPA. If a reasonable <br />technology or method emerges that has a high probability of success and good potential <br />to improve resource protection and recovery, AmerAlia will also test that technology or <br />method. <br />