The article focuses on the mining and consumption of ball clay. It states that ball clay producers primarily sold clays to ceramic floor and wall tiles, along with exports and sanityware. It mentions four companies mined ball clay in four U.S. states in 2013, including H.C. Spinks Clay Co., Old Hickory Clay, and Unimin Corp. It comments on imports of ball clay in 2013 according to statistics from the U.S. Census Bureau.