The Madison Heights salt storage dome is a Monolithic Dome with a large extended augment. It was built by South Industries in 2021, replacing an uninsulated concrete dome built in the 1970s by Horal Harrington. The sandstone-colored half-sphere holds 4000 tons (3629 mt) of salt. Depending on the weather in Madison Heights, Michigan, it might need only a single refill per year.
The new dome is 92-foot (28 m) diameter by 33-foot (10 m) tall with an 18-foot (5.5 m) by 18-foot (5.5 m) augmented opening. It was constructed atop a concrete foundation on a spread footing. The interior has two ventilation fans, and two large LED lights hung from the dome itself.
In 2018, the city of Madison Heights was contemplating how to replace the old salt storage dome from the 1970s. They were surprised to discover that the cost difference of a Monolithic Dome compared to a conventional structure was less than they expected. They traveled to other municipalities and inspected their salt storages. They concluded the small premium paid for the Monolithic Dome was worth it because of its longevity, ease of maintenance and protection from the elements.
“We are happy with the dome,” said Sean Ballentine, director of public services. “It has thus far proven to be durable and low maintenance, as opposed to a wood-and-shingle structure. We wanted something low maintenance that would last us at least another fifty years.” The salt storage dome meets the top requirements for the Salt Institute’s SALTED standards of Safety, Accessibility, Legality, Tidiness, Economics, and Drainage.