The data published with NAICS code 212325 include the following SIC industry:
1459 Clay, ceramic, and refractory minerals, n.e.c.
This definition comes from the 1997 NAICS manual. However, for this industry, the 1997 Economic Census Mining did not fully implement the conversion to NAICS. Data for NAICS industry 212325 do not include establishments only engaged in beneficiating or preparing clay, ceramic and refractory minerals. The NAICS definitions will be fully implemented with the 2002 Economic Census.