Amos Sequence 4 Landfill Expansion
R. B. Jergens (RBJ) was contracted to perform a 30 acre landfill cell expansion to provide future airspace for coal combustion residue disposal. The project involved blasting and excavating almost 1,700,000 CY of natural hilltop material to provide fill material within a valley needing 3:1 design grade slopes. In addition to the mass earthwork required to achieve design, this project was defined by a natural ridge that separated storm and leachate water management from the previously constructed cells. This required management of natural springs with 2,000 feet of C900 PVC underdrain piping and 4,800 feet of schedule 80 PVC leachate collection piping on top of the synthetic liner system. Field activities began in March 2018 and the project completed in August 2020.
The projected presented the RBJ Team with several water management challenges such as a large watershed area that culminated into a narrow valley in which the landfill cell sat in the middle. Above average storm events coupled with natural springs challenged the team to control erosion damage from rain events. Water conveyance to the sediment control features downstream from the cell construction was achieved with an added fabric formed concrete ditch that was installed in the coldest month of the year. This challenge included cold working temperatures, concrete batch plant availability, and proper curing of the finished product using blankets and indirect flame heaters. The project was ultimately completed on time and under budget.
