Sand, gravel, clay, and ceramic and refractory minerals mining and quarrying

North American Industry Classification System code (NAICS): 21232

This industry comprises establishments primarily engaged in operating sand and gravel pits, including dredging for sand and gravel; mining or quarrying shale; and mining, beneficiating or otherwise preparing kaolin or ball clay, including china clay, paper and slip clays, and other clays and refractory minerals.