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Coulson Excavating Company, Inc. - Bouser Gravel Pit Exhibit E - Reclamation Plan Table 1 Empirical Relationship Range Of Hydraulic Conductivity (ft/day) Plasticity Index (as measured) :Hydraulic Conductivity 5.6x10 to 8.4x10 Fines (as measured) :Hydraulic Conductivity 2.9x I Oa to 2.9x104 Clay Content :Hydraulic Conductivity 2.9x10 to 5.7x10"5 In the same paper, Benson et a/. also correlated plasticity index with clay content. With a plasticity index of 24, clay content can vary between 200%. This content is sufficient enough to facilitate a low hydraulic conductivity after compaction. Daniel (1990) recommends a plasticity index of at least 10 for a material to be suitable for lining. In addition, Daniel and Koerner (1993) suggest a minimum of 50% fines for a suitable liner material, and with 95.6% fines, the soil sample material exceeds this criteria. Liner Design/Saecifications The liner is to be constructed with weathered Pierre shale from the Bonser pit. The moisture content during construction will be 15% to IS% (I % dry of optimum or 2% wet of optimum). This content is under the plastic limit, and will allow the soil to remold to a homogenous low wnductivity material. Liner material will be laid down in two I ft lifts. A 35,000 Ib Caterpillar 316 sheep's-foot roller will compact each lift of soil. Each foot on the roller measures 12 in. The roller covers 20% of the ground with each pass, requiring four passes over each lift to ensure complete compaction. Full penetration of the sheep's-foot ensures bonding of the lifts. ARer the liner has been compacted, the reservoir will be used for water storage purposes. The native water table surrounding the pit is approximately 4'-9' below ground surface. Tfie liner will be designed to overcome the hydrostatic pressure exerted against the liner wall from groundwater, even with the absence of water in the reservoiv. Constructing the liner with the correct thickness, in addition to the presence of the fill material beneath the liner, will acwmplish this objective. Depression of the surrounding water table will continue until the reservoir has been filled. The liner will be constructed to meet the following specifications: a) The liner soil will contain a minimum of 50 percent material passing the No. 200 sieve on a dry weigfit basis, b) The liner soil will have a plasticity index of 10 to 35 percent, c) The percentage of gravel, defined as material retained on the No. 4 sieve, will not exceed I O percent, d) The liner soil will be compacted to a minimum of 95 percent maximum dry density as determined by the Standard Proctor (ASTM D698),