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stockpile will be located on TC owned lands and includes previously disturbed areas near the existing
<br />Weather Station (access road) and reclaimed spoil areas to the northeast. Site preparation will be limited
<br />to construction of a short access road segment from the existing Refuse Haulroad, minor grading of the
<br />existing disturbed areas in the vicinity of the Weather Station, removal of soil and suitable cover material
<br />from any portions of the reclaimed areas within the new stockpile area footprint which need to be
<br />regraded, and minor grading of the southern portion of the stockpile area to establish a suitable stockpile
<br />foundation. The proposed new stockpile area drains to existing designed CRDA drainage structures,
<br />(RDA -5A and RDA -7) so no additional drainage design or structures will be needed. It is anticipated that
<br />a berm, sediment control material, and/or wattles will be placed on the downgradient side of the new soil
<br />stockpile to limit sediment transport from the stockpile area in order to minimize ditch maintenance
<br />requirements, and that the Stockpile (except for a limited active placement area) will be reseeded with a
<br />temporary cover mixture to control erosion and sediment loss. Soil material volumes and recovery and
<br />stockpiling operations are summarized by Table 49A, Soil Stockpile Summary.
<br />Similar to the planned soil handling operations described, TCC will also recover, stockpile, and replace suitable
<br />cover materials to meet the applicable regulatory standard of 4 feet of suitable cover over the regraded coal refuse
<br />materials. Engineering projections indicate that a maximum of approximately 253,500 cubic yards of soil material,
<br />and 571,600 cubic yards of suitable cover material will need to be recovered and replaced during the life of the
<br />CRDA Expansion. Soil and cover material handling operations are summarized by Table 49A, Soil Stockpile
<br />Summary, and in Exhibit 26C. Both soil and cover material stockpiles will be placed, graded, and stabilized to
<br />prevent loss or contamination of these materials, and to minimize erosion potential. Potential runon and runoff
<br />from the piles will be controlled by a closed system of ditches and berms, and the piles will be stabilized by seeding
<br />with a rapid -germinating temporary cover seed -mix (refer to Table 54, Cropland Seed Mix). Soil stockpiles will be
<br />posted with identifying signage, which will be maintained so long as material remains in the stockpile(s).
<br />Construction of the Coal Refuse Haulroad will proceed simultaneously with soil and cover removal operations for
<br />the refuse toe bench. The proposed haulroad will be approximately 2,300 feet long, with a traveled surface
<br />approximately 30 feet wide. Following soil material removal from the road alignment, the road footprint will be
<br />scarified and cut/fill operations will establish the general road configuration, as shown in the design documentation
<br />provided in Exhibit 26C, Coal Refuse Disposal Area Expansion Designs. Fills will be placed and compacted in
<br />uniform lifts of 6-8 inches. The road surface will consist of approximately 6 -inches of well -graded aggregate base,
<br />overlain by approximately 18 -inches of pit run road base materials, compacted to 95 percent of maximum dry
<br />density. Road drainage will be addessed by designed ditches and culverts, sized to safely pass the runoff from the
<br />10 -year, 24-hour storm event. Design documentation and the required P.E certification for road designs are
<br />presented in Exhibit 26C, Coal Refuse Disposal Area Expansion. The Coal Refuse Haulroad will provide for
<br />material haulage from the Coal Refuse Hopper(s) to the CRDA Expansion area. Haulage within the CRDA
<br />Expansion area, including haulage on benches, will occur on temporary roads established within the CRDA
<br />footprint and typically on established refuse fill areas.
<br />Following soil material removal, construction will begin on both the perimeter drainage control ditches and the
<br />CRDA toe drain. Because the CRDA Expansion will be constructed in phases, initial perimeter ditches will be
<br />constructed as temporary ditches, designed to safely pass the runoff from the 10 -year, 24-hour storm event.
<br />Permanent perimeter ditches have been designed and will be constructed to safely pass the peak flows from the
<br />100 -year, 24-hour design storm event. In order to control flow velocities and facilitate vegetative reestablishment
<br />in the permanent perimeter ditches, temporary rock check -dams may be constructed in these ditches in accordance
<br />with the design parameters previously outlined for the existing CRDA. Because infiltration through the pile to the
<br />CRDA Expansion foundation area would occur gradually over time, regardless of storm event, the toe drain has
<br />been designed based on the 10 -year, 24-hour precipitation event. The toe drains primary purpose is to prevent any
<br />significant build-up of hydrostatic pressure within the pile, which could affect pile stability. Based on design
<br />calculations, the required toe drain would consist of durable 9 -inch rock with a cross-sectional area of
<br />approximately 50 square feet, enclosed by graded cover material to minimize the potential for fines infiltration and
<br />plugging. A minor drainage design modification, incorporated during the initial construction phase, will shift the
<br />northern end of the toe drain approximately 120 feet to the east, allowing the toe drain to discharge to the Area 1 Pit
<br />rather than Sedimentation Pond D. This minor design modification will allow for use of any drainage in the mine
<br />MRI 5-290 2.05-97.4 10/02/15
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