The Bussen family has operated one of the largest limestone quarries in the Midwest here, on the Mississippi River, south of St. Louis, since 1882. Though most of the excavation has been as an open pit, more than 100,000 square feet has been mined underground, and around half of it converted into business park-type space. Tenants include a frozen seafood importer, a beer distributor, an in-plant office structure manufacturer, a meal service provider, an industrial steel furniture fabricator, and a fulfillment company. The main quarry and river terminal activities of the 600 acre site surround the commercial underground.