Southard Gypsum Mine, Oklahoma

Oklahoma is sometimes ranked as the largest domestic producer of gypsum, and this facility in northwestern part of the state is one of a few major mines and plants for the material in the state. It is operated by US Gypsum, the largest manufacturer of gypsum products in the country, which include wallboard, joint compound, and ceiling panels; some of the most common materials used in building construction. Despite the nationwide reach of the company, it operates only eight mines and quarries in the USA.