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Coulson Excavation Company Inc. -Stroh Gravel Pit <br />Exhibit E -Reclamation Plan <br />Density 117.7 pcf <br />The goal of the design is to minimize hydraulic conductivity. Empirical relationships between <br />plasticity index and clay content, plasticity index and hydraulic conductivity, percent fines and <br />hydraulic conductivity, and clay content and hydraulic conductivity, have been shown by Benson <br />et al. (1992). The ranges of hydraulic conductivities for the plasticity index of the sampled <br />material are shown in Table 1. <br />Table 1 <br />E <br />Plasticity Index (24) Vs Hydraulic 5.6x10-6 to 8.4x10' <br />Conductivity (Benson et al 1992) <br />Fines (95.9%) Vs Hydraulic Conductivity 2.9x10 ~ to 2.9x10 <br />(Benson et al 1992) <br />The plasticity index can be correlated with clay content. Empirical data gathered by Benson et al. <br />(1992) show that soils with a plasticity index of 24 have a clay content of between 20% and <br />40%. Clay content is related to hydraulic conductivity in the same paper by Benson et al 1992, <br />with a range of 2.9x10.6 ft/day to 5.7x10"5 ft/day for. <br />A plasticity index of 24 indicates that the soil contains enough clay to facilitate a low hydraulic <br />conductivity value after compaction. Daniei (1990) recommends that a soil have a plasticity <br />index at least 10 in order to be sufficiently plastic for a liner material. <br />Daniel and Koerner (1993) suggest that a suitable compacted liner material will contain a <br />minimum of 50% fines. With 95.6% fines, the soil sample material also exceeds this criterion. <br />Liner Desien/Soecifications <br />The liner is to be constructed with weathered Pierre shale from the Stroh pit, with a thickness of <br />2 ft. The moisture content during construction will be 10% to 20% (1% dry of optimum or 2% <br />wet of optimum). This content is under the plastic limit and, therefore, the soil will remold to a <br />homogeneous a low conductivity material. <br />Liner material will be laid down in two 1 ft lifts. A 53,000-pound Caterpillar 316 sheep's-foot <br />roller will be used to compact each lift of soil. Each foot on the roller measures 12 inches. The <br />roller covers 20% of the ground with each pass, so four passes will be made over each lift to <br />ensure complete compaction. Full penetration of the sheep's foot ensures bonding of the two <br />lifts. After the liner has been compacted, subsoil and topsoil will be placed on top of the liner. <br />This will be the final design configuration. <br />Construction Procedure <br />Borrow material will be spread over the area in two 1-foot lifts. A sheep's foot roller will then <br />compact the lifts by making no less than four passes over the entire surface. The moisture <br />content of the soil will be tested just prior to compaction of the first lift. ASTM Method D-4643 . <br />will be used to determine field moisture content. It is expected from earlier field moisture content <br />