2008-04-22_PERMIT FILE - C1981017 (15)

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Chapter II Golder & Associates verified that the existing sedimation ponds were adequately • sized to meet regulatory requirements for the Phase II Pile, with minor modifications, when operated in series because the ponds were initially designed very conservatively so that either pond acting independently would meet regulatory requirements for the Phase I pile. The modification recommended was to lower the dewatering hole in the principal spillway riser pipe on the lower pond by 18 inches in order to meet the runoff storage requirements of the regulations. (3) Sutey -Operation and Maintenance. The disposal site is inspected quarterly by a qualified registered professional engineer to determine that it is being constructed as specified in the design. Terraces associated with the coal refuse pile have been designed for structural stability. During operation, the waste is placed in a controlled manner and compacted as approved by the department. The rill and gully maintenance and repair program, approved as a minor revision on July 24, 1985, says that for the Sutey pile: As the pile progresses upward a 2:1 outslope will develop. Before. topsoiling occurs • the area will be inspected each spring and any rills and gullies noted. As the area dries out, mechanical equipment wilt be used to reshape the area. After topsoiling, inspections to identify erosion problems will be conducted once per month from May through July. Inspection will also be made after any significant rainfall event. tf any (problems) are noted, temporary control will be established by hay bales or parts of bales being placed at prudent intervals along the rill or gully within 10 days of detection. When the refuse pile dries out (generally July or August), mechancial methods will be used to remove or fill the rills and gullies, vegetation: i.e., small rubber-tired backhoe or D-3 tractor. In some cases (steep slope areas) (1:1 only) soil conservation type log or rock check dam structures will be utilized. All disturbed areas will be reseeded and mulched using hand-broadcast methods, thus again minimizing any impact to existing vegetation. Sediment pond cleanings are placed on the Sutey pile, as approved by a Minor Revision on July 11, 1985, as part of Mid-Continent's normal sediment pond maintenance program. Usually, such clean-out procedures start about April and continue on through the snow-free months. The muck from the ponds is truck-hauled to the refuse pile and placed at random intervals across the pile. The coal refuse is spread out in a fan shape one to two feet thick and the sediment from the ponds is spread out in layers of six inches or less across the top of the pile, so that it will not be concentrated in any one area. J 41