The parent company of Knife River Corp., MDU Resources Group reported third-quarter earnings of $92.3 million, or 49 cents per share, up 28.4 percent from the same period last year when it earned $71.9 million, or 38 cents per share.

The parent company of Knife River Corp., MDU Resources Group reported third-quarter earnings of $92.3 million, or 49 cents per share, up 28.4 percent from the same period last year when it earned $71.9 million, or 38 cents per share.

MDU's Knife River unit paves roads and supplies aggregate, ready-mix, sand and gravel among other services. MDU said its construction materials and services businesses reported their best quarter since 2007 as their earnings climbed 37.8 percent to $61.4 million from $51.8 million last year.

The North Dakota-based company said its construction materials group's work backlog increased to $958 million compared to $834 million a year ago. The backlogs includes highway paving projects, airports, bridge work, reclamation, harbor expansions, substation and line construction, solar and industrial projects including refinery work.

— Greg Stiles