0000950120-97-000250 424B5 1 19970915 NYSE PSE MDU RESOURCES GROUP INC 0000067716 4932 410423660 DE 1231 424B5 33 033-46605 97680645 400 N FOURTH ST BISMARCK ND 58501 7012227900 400 NORTH FOURTH ST BISMARCK ND 58501 MONTANA DAKOTA UTILITIES CO 19850429 424B5 1 000095012097000250-001-seq1-424b5.txt PROSPECTUS SUPPLEMENT