INSTRUMENT OF AMENDMENT TO THE
MDU RESOURCES GROUP, INC.
401(k) RETIREMENT PLAN

The MDU Resources Group, Inc. 401(k) Retirement Plan, as restated March 1, 2011
and further amended (the “Plan”), is hereby further amended, effective September
23, 2013, as follows:

By adding the following new entry to Schedule B:

Knife River Corporation - Northwest (Utah Division) shall make supplemental
contributions on behalf of its Davis‑Bacon Employees in such amounts as may be
necessary to satisfy the required Prevailing Wage Law fringe cost without regard
to any employer Matching Contributions pursuant to Supplement G.
Effective as of September 23, 2013.
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Explanation: This amendment provides the manner in which the above Participating
Affiliate is implementing the provisions of the Davis-Bacon (Supplement G)
feature.

IN WITNESS WHEREOF, MDU Resources Group, Inc., as Sponsoring Employer of the
Plan, has caused this amendment to be duly executed by a member of the MDU
Resources Group, Inc. Employee Benefits Committee (“EBC”) on this 23 day of
September, 2013.

 
 
MDU RESOURCES GROUP, INC.
 
 
EMPLOYEE BENEFITS COMMITTEE
 
 
 
 
 
 
BY:
/s/ Doran N. Schwartz
 
 
 
Doran N. Schwartz, Chairman