This industry group comprises establishments primarily engaged in (1) manufacturing portland, natural, masonry, pozzolanic, and other hydraulic cements; (2) acting as batch or mixing plants, producing concrete to be delivered to the customer in a plastic and unhardened state; (3) manufacturing concrete pipe brick, and block; and (4) manufacturing other concrete products (except block, brick, and pipe). Cement manufacturing establishments may calcine earths, or mine or quarry.