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Empirical Relationship <br />Range Of Hydraulic Conductivity <br />(feet/day) <br />Plasticity Index (as measured) and <br />Hydraulic Conductivity <br />5.6x10 -6 to 8.4x10 <br />% Fines (as measured) and Hydraulic <br />Conductivity <br />2.9x10 to 2.9x10 <br />Clay Content (20 -40 %) and Hydraulic <br />Conductivity <br />2.9x10 -6 to 5.7x10 -5 <br />EXHIBIT E — RECLAMATION PLAN <br />Table 1 <br />In the same paper, Benson et al. also correlated plasticity index with clay <br />content. With a plasticity index of 24, clay content can vary between 20 -40 %. <br />This content is sufficient enough to facilitate a low hydraulic conductivity after <br />compaction. Daniel (1990) recommends a plasticity index of at least 10 for a <br />material to be suitable for lining. In addition, Daniel and Koerner (1993) suggest a <br />minimum of 50% fines for a suitable liner material, and with 95.6% fines, the soil <br />sample material exceeds this criterion. <br />Liner Design /Specifications <br />The liner is to be constructed with weathered Pierre shale from the Challenger <br />pit. The moisture content during construction shall be 15% to 18% (1% dry of <br />optimum or 2% wet of optimum). This moisture content is slightly above the <br />plastic limit, and will allow the soil to remold to a homogenous, low- conductivity <br />material. <br />Liner material will be placed in 1 -2 foot lifts. A 35,000 lb Caterpillar 316 sheep's - <br />foot roller will compact each lift of soil. Each foot on the roller measures 12 <br />inches in length. The roller covers 20% of the ground with each pass, requiring <br />four passes over each lift to ensure complete compaction. Full penetration of the <br />sheep's -foot will ensure bonding of the lifts. <br />The native water table surrounding the proposed pit boundaries is approximately <br />4 -9 feet below existing ground surface. The liner will be designed to withstand <br />the hydrostatic pressure exerted against the liner wall due to groundwater, even <br />with the absence of water in the pond. Constructing the liner with the correct <br />thickness and compaction will accomplish this objective. Depression of the <br />surrounding water table will be accomplished through keeping the dewatering <br />gap open during construction. The liner will be constructed to meet the following <br />specifications: <br />a) The liner soil will contain a minimum of 50 percent material passing the <br />No. 200 sieve on a dry weight basis; <br />Chpllenger Pit <br />M-1980-026 TR -04 <br />9 Page3of6 <br />