My father told me his Aunt Eva James Burns and her husband Ralph Burns had their hands in many businesses. Ralph was invited to drive in the opening parade of the Mackinaw Bridge, the bridge that connects the lower and upper peninsulas of Michigan, because his company supplied concrete materials that were used to build it.
Ralph Burns’s obituary* states that he retired from Catsman, which was a conglomerate “of real estate, coal, fuel oil and concrete companies” owned by millionaire Samuel Catsman. I would assume this is the company that supplied concrete to build the Mackinaw Bridge but I have not verified.
The Burnses had a small conglomeration of their own, investing in a market, restaurants, and bars around the Flint area. Here is Aunt Eva at the MerryInn Bar that had been on Franklin Street. It became a gay bar with the same name in the early 2000s.
*Obituary of Robert Burns, Flint Journal (Flint, MI), 26 Nov 1987, personal records.