Laserfiche WebLink
6.4.5 Exhibit E — Reclamation Plan <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 Bonser pit. <br />The moisture content during construction will be 15% to 18% (1 % dry of optimum <br />or 2% wet of optimum). This moisture content is slightly above the plastic limit, <br />and will allow the soil to remold to a homogenous, low- conductivity 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 />b) The liner soil will have a plasticity index between 10 and 35; <br />c) The percentage of gravel, defined as material retained on the No. 4 sieve, <br />will not exceed 10 percent; <br />d) The liner soil will be compacted to a minimum of 95 percent maximum dry <br />density as determined by the Standard Proctor (ASTM D698); <br />e) No brush, roots, sod, frozen material, or other deleterious or unsuitable <br />materials shall be incorporated into the fill. Fill shall not be placed upon <br />frozen material; <br />f) If moisture conditioning is required to meet the moisture content <br />specification, the added moisture shall be worked into the fill by harrowing <br />or other means until a uniform distribution of moisture is obtained; <br />g) Compacted soil liner fill shall be protected from desiccation and from <br />freezing. The finished soil liner will be covered as soon as practicable with <br />water as shown in the reclamation plan. If evidence of desiccation or frost <br />damage is observed, the soil liner will be reworked and retested as <br />necessary to demonstrate that the compaction specification is met, <br />