This major group includes establishments primarily engaged in mining or quarrying, developing mines, or exploring for nonmetallic minerals, except fuels. Also included are certain well and brine operations, and primary preparation plants, such as those engaged in crushing, grinding, washing, or other concentration.

Establishments primarily engaged in manufacturing cement are classified in Industry 3241; those engaged in manufacturing lime are classified in Industry 3274; those engaged in cutting and finishing stone and stone products are classified in Industry 3281; and those engaged in manufacturing brick and other structural clay products are classified in Industry Group 325.

Establishments primarily engaged in crushing, pulverizing, or otherwise treating earths, rocks, and minerals mined in Industry Group 145 or Industry Group 149; or barite mined in Industry 1479, not in conjunction with mining or quarrying operations, are classified in Manufacturing, Industry 3295; establishments primarily engaged in these activities in conjunction with mines or quarries are classified in Mining. Establishments primarily engaged in crushing, pulverizing, or otherwise treating other nonmetallic minerals are classified in Mining, whether or not they are operated in conjunction with mines.

Establishments primarily engaged in manufacturing other stone, clay, glass, and concrete products from minerals mined at the same establishment are classified in Manufacturing, Major Group 32, when separate reports are not available for the mining and manufacturing activities.