New Galilee, Pennsylvania
Clay was an abundant resource in Beaver county. According to the 1955 circular of the Pennsylvania Geological Survey, In 1955 Beaver County produced 13.7% of Pennsylvania's total clay output. There were 13 companies that mined clay in Beaver county at that time. Two of these companies, The Negley Fire Clay Co. and Ralph A. Veon, Inc. mined fire clay of the plastic variety from open pits and marketed the output for use in manufacturing fire brick and block, foundries, and heavy clay products. In addition, Ralph A. Veon, Inc., mined and sold fire clay of the burley variety. In 1955, New Castle Refractories mined stoneware clay from an underground mine near New Galilee for use locally in manufacturing pouring channels
Ub, Serbia
The following table gives a preview of total number of employed people per their core activity (as of 2016):
There are several mines and resource centers of coal (Radljevo field - 344,000,000 tones, Zvizdar field - 280,000,000 tones), clay, sand, stone and limestone.
The biggest producer of quartz sand in Serbia is "Kopovi a.d.", with overall production of over 400,000 tones per year. 
Clay pits are based below the layers of sand and quartz sand. Municipality of Ub is the biggest supplier of high-quality clay in Serbia. There are more than 1,800,000 tones of clay.