Natural Molding Sand: Historic Hoosier Mineral Resource (IM-05)
Natural molding sand is a mixture of clay, silt and sand that can be used in foundries. It can be taken directly from the pit and used to make molds.

Little natural molding sand is used today because foundries prefer to make their own blend of materials by mixing together sand, clay and resins. But in the late 1800s and early 1900s, natural molding sand was extensively used. In 1926 Indiana ranked second in the United States in total production. This abundant material helped Indiana become a leading state in producing metal castings, an industry that developed along with iron and steel making in northwestern Indiana. For example, the Bradford Sand Co. at Bradford Woods near Martinsville produced molding sand for the Indianapolis area.

Our Hoosier State Beneath Us: Industrial Minerals