processed minerals for use in numerous industries as an ingredient in the manufacture of bricks, tiles, sanitaryware, electrical porcelain, art ceramics, stoneware, earthenware, plastic refractories, castable refractories, refractory mortars, insulating firebrick, modeling clay, foundry strainer cores, molten metal filters, parting compound, foundry mold and core washes, fired shapes, kiln and kiln car materials, ramming mixes, industrial fillers, gunning mixes, face brick coatings, investmen...