AECOM has performed gypsum stack operations and maintenance services in southeast Idaho for nearly 40 years. This project – the $37.7 Million Impoundment construction and maintenance for sluiced gypsum and wash water waste streams – is the latest. The work includes siphon cell construction and operations for slurry dewatering; cut/fill scraper and dozer operations in the construction of gypsum slurry impoundments; and rim ditching saturated gypsum slurry for generating embankment material with long reach excavators