Description: This industry comprises establishments primarily engaged in developing the mine site, mining, and/or beneficiating (i.e., preparing) ores valued chiefly for their copper, nickel, lead, or zinc content. Beneficiating includes the transformation of ores into concentrates. Establishments primarily engaged in recovering copper concentrates by the precipitation, leaching, or electrowinning of copper ore are included in this industry. Cross-References. Establishments primarily engaged in--