 NEW YORK, Jan. 14, 2021 GLOBE NEWSWIRE -- Specialty Minerals Inc. SMI, a subsidiary of Minerals Technologies Inc. NYSE: MTX MTI or the Company, has communicated to customers that it has increased prices across its mineral product portfolio, effective January 1, 2021. Price increases range from 3 to 10, subject to individual customer contracts and terms. The price increases help to offset rising costs and will support SMIs continued investments in mining, processing operations, and new product technology. 