Exhibit 23(c) CONSENT OF ENGINEER We hereby consent to the incorporation by reference in this Post-Effective Amendment No. 1 to the registration statement on Form S-8 filed by MDU Resources Group, Inc. with the Securities and Exchange Commission on October 29, 1992 (Registration No. 33- 53898) of our report, dated May 9, 1994, which appears in or is incorporated by reference in the MDU Resources Group, Inc. Annual Report on Form 10-K for the year ended December 31, 1994. /s/ Kenneth J. Girard WEIR INTERNATIONAL MINING CONSULTANTS October 12, 1995 Des Plaines, Illinois