2010-03-17_REVISION - M2000156 (6)

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6.4.5 Exhibit E - Reclamation Plan 7) Following backfilling Phase 2 Cell 3, begin constructing the clay liner for the main lake by ripping weathered shale from pit floor and placing on the slopes and compacting. 8) Following Construction of the clay liner in the main reservoir, begin construction of the clay liner in Phase 2 Cell 3. 9) Remove screening berm in the North east corner of the permit area and use material to backfill dewatering gap. 10) Backfill dewatering gap with approximately 20,600 yd3 of overburden. 11)Replace topsoil as shown in Exhibit F - Reclamation Plan (40,333 cy). 12)Disk, seed and fertilize areas as shown in Exhibit F - Reclamation Plan. Table 6.4.4-3 - Reclamation backfill Volume Summary Phase/Cell Overburden to backfill Acres to backfill 1/1 149,064 yd -5 acres 1 /2 71,966 yd -5 acres 2/1 311,790 yd -10 acres 2/2 8,258 yd -0.25 acres 2/3 -38,000 yd -1 2/4 72,559 yd -2 2/5 164,580 yd -5 TOTAL 816,000 yd 25.25 acres total CLAY LINER DESIGN AND SPECIFICATIONS The purpose of this section is to provide design specifications for the pond liner. A compacted clay liner is designed to prevent groundwater leakage into the pond at a design rate of less than 0.03 feet3 / day / feet2, as specified by the Colorado Office of the State Engineer (SEO). The borrow source for the compacted clay liner will be the weathered zone of Pierre shale occurring an average depth of 17-18 feet below ground surface. Texturally and mineralogically continuous in a lateral direction, the Pierre shale is flat lying in this area (Porter, 1976). The weathered zone is a friable silty clay consisting of illites and small amounts of smectites (Gill et al, 1996). Approximately 69,000 cy of weathered Pierre shale will be required to construct the clay liner for the 55 acre lake and 11,500 cy with be required for the 2 acre lake.