The parent company of aggregate and paving company Knife River Corp. is now a member of the Fortune 500.

The parent company of aggregate and paving company Knife River Corp. is now a member of the Fortune 500.

MDU Resources Group Inc., based in Bismark, N.D., is ranked No. 473 on the 2009 Fortune 500 list. It operates in 44 states, had 2008 revenue of $5 billion and has about 10,000 employees.

In addition to Knife River Corp., which is one of the 10 largest aggregate producers in the country and has a Central Point location, MDU operates natural gas and electric utilities and construction units.

— Greg Stiles