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Cedar Hills Regional Landfill

PROJECT | WASHINGTON

MAPLE VALLEY, WA

The Cedar Hills Landfill was broken up into two major schedules. The Area 7 Stage II Closure consisted of grading 7.2 acres of slope face, placing 3.1 acres of geo-synthetic clay liner with soil cover, four acres of LDPE liner and HDPE gas collection lines and drainage facilities. The SSWA excavation included 750,000 cubic yards of refuse and soil excavation and construction of a 4,000-foot-by-30-foot wide asphalt road with construction of 3,200 feet of an 8-inch HDPE water line and fiber optic.
Also included in the SSWA was screening of 50,000 yards of municipal waste which resulted in pulling out 35 percent dirt, which was later used as cover soils for the active landfill and saved 35 percent of air space for future municipal waste. 
The project team also constructed a haul road up the middle of the south-facing slope with 60,000 yards of material. The project team proposed this idea at no cost to the owner, which cut down on haul time and project risk. Also, the project team built massive, 3-foot-high steel sideboards on three sides of the haul trucks since the refuse was so light—and they were able haul up to 35 cubic yards in the 40-ton trucks.