Participating Utilities Announce Wind-Down of Big Stone II Project

BISMARCK, N.D.--(Business Wire)--
MDU Resources Group, Inc. (NYSE:MDU) announced today that the Big Stone II
Project, a planned 500-to-600-megawatt coal-fired power plant to be located near
Milbank, South Dakota, and its associated transmission, will not be built. The
project`s four participants include Montana-Dakota Utilities Co., a division of
MDU Resources.

The project required additional participants to move forward; however none have
committed.

Montana-Dakota President and Chief Executive Officer Dave Goodin said that,
while it`s disappointing that Big Stone II will not be built, the utility has an
adequate electric supply for the near-term.

"We have a purchased power agreement through 2015 that was to bridge us to Big
Stone II going online; we still have that agreement in place," Goodin said. "We
will now look at other supply options that are reliable and cost-beneficial for
our customers. We have plans to expand our wind production by 30 megawatts in
2010 and will review other generation options."

The other Big Stone II Project participants were Central Minnesota Municipal
Power Agency, Heartland Consumers Power District and Missouri River Energy
Services.

MDU Resources Group, Inc., a Fortune 500 company and a member of the S&P MidCap
400 index, provides value-added natural resource products and related services
that are essential to energy and transportation infrastructure, operating in
three core lines of business: energy, utility resources and construction
materials. MDU Resources includes natural gas and oil production, natural gas
pipelines and energy services, electric and natural gas utilities, construction
services, and construction materials and contracting. For more information about
MDU Resources, see the company's Web site at www.mdu.com.

MDU Resources Group, Inc.
For financial inquiries, contact:
Vernon A. Raile, 701-530-1003
Executive Vice President, Treasurer and Chief Financial Officer
or
Phyllis A. Rittenbach, 701-530-1057
Director of Investor Relations
or
For media inquiries, contact:
Mark Hanson, 701-530-1093
or mark.hanson@mduresources.com
Public Relations Representative

Copyright Business Wire 2009