EXHIBIT 15 ACCOUNTANTS' ACKNOWLEDGMENT The Board of Directors Minerals Technologies Inc: Re: Registration Statement Nos: 33-59080, 33-65268 and 33-96558 With respect to the subject registration statements, we acknowledge our awareness of the use therein of our report dated July 31, 1998, related to our review of interim financial information. Pursuant to Rule 436(c) under the Securities Act of 1933, such report is not considered a part of a registration statement prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of the Act. Very truly yours, KPMG Peat Marwick LLP New York, New York August 6, 1998