UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

ý	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
	THE SECURITIES EXCHANGE ACT OF 1934

For The Quarterly Period Ended June 30, 2013

OR

o	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
	THE SECURITIES EXCHANGE ACT OF 1934

For the Transition Period from _____________ to ______________

Commission file number 1-3480

MDU Resources Group, Inc.

(Exact name of registrant as specified in its charter)

Delaware	41-0423660
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

1200 West Century Avenue

P.O. Box 5650

Bismarck, North Dakota 58506-5650

(Address of principal executive offices)

(Zip Code)

(701) 530-1000

(Registrant's telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ý No o.

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes ý No o.

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definition of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act (Check one):

Large accelerated filer ý	Accelerated filer o
Non-accelerated filer o	Smaller reporting company o

(Do not check if a smaller reporting company)

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes o No ý.

Indicate the number of shares outstanding of each of the issuer's classes of common stock, as of July 31, 2013: 188,830,529 shares.

DEFINITIONS

The following abbreviations and acronyms used in this Form 10-Q are defined below:

Abbreviation or Acronym
2012 Annual Report	Company's Annual Report on Form 10-K for the year ended December 31, 2012
Alusa	Tecnica de Engenharia Electrica - Alusa
ASC	FASB Accounting Standards Codification
BART	Best available retrofit technology
Bbl	Barrel
Bicent	Bicent Power LLC
Big Stone Station	475-MW coal-fired electric generating facility near Big Stone City, South Dakota (22.7 percent ownership)
BLM	Bureau of Land Management
BOE	One barrel of oil equivalent - determined using the ratio of one barrel of crude oil, condensate or natural gas liquids to six Mcf of natural gas
BOPD	Barrels of oil per day
Brazilian Transmission Lines	Company's equity method investment in the company owning ECTE, ENTE and ERTE (ownership interests in ENTE and ERTE were sold in the fourth quarter of 2010 and portions of the ownership interest in ECTE were sold in the third quarter of 2012 and the fourth quarters of 2011 and 2010)
Btu	British thermal unit
Calumet	Calumet Specialty Products Partners, L.P.
Cascade	Cascade Natural Gas Corporation, an indirect wholly owned subsidiary of MDU Energy Capital
CCU	Cane Creek Unit
CELESC	Centrais Elétricas de Santa Catarina S.A.
CEM	Colorado Energy Management, LLC, a former direct wholly owned subsidiary of Centennial Resources (sold in the third quarter of 2007)
CEMIG	Companhia Energética de Minas Gerais
Centennial	Centennial Energy Holdings, Inc., a direct wholly owned subsidiary of the Company
Centennial Capital	Centennial Holdings Capital LLC, a direct wholly owned subsidiary of Centennial
Centennial Resources	Centennial Energy Resources LLC, a direct wholly owned subsidiary of Centennial
Colorado State District Court	Colorado Thirteenth Judicial District Court, Yuma County
Company	MDU Resources Group, Inc.
Coyote Creek	Coyote Creek Mining Company, LLC, a subsidiary of The North American Coal Corporation
Coyote Station	427-MW coal-fired electric generating facility near Beulah, North Dakota (25 percent ownership)
Dakota Prairie Refinery	20,000 barrel per day diesel topping plant being built by Dakota Prairie Refining in southwestern North Dakota
Dakota Prairie Refining	Dakota Prairie Refining, LLC, a limited liability company jointly owned by WBI Energy and Calumet
dk	Decatherm
Dodd-Frank Act	Dodd-Frank Wall Street Reform and Consumer Protection Act
ECTE	Empresa Catarinense de Transmissão de Energia S.A. (5.01 percent ownership interest at June 30, 2013, 2.5, 2.5 and 14.99 percent ownership interests were sold in the third quarter of 2012 and the fourth quarters of 2011 and 2010, respectively)
ENTE	Empresa Norte de Transmissão de Energia S.A. (entire 13.3 percent ownership interest sold in the fourth quarter of 2010)
EPA	U.S. Environmental Protection Agency
ERTE	Empresa Regional de Transmissão de Energia S.A. (entire 13.3 percent ownership interest sold in the fourth quarter of 2010)
EUR	Estimated ultimate recovery
Exchange Act	Securities Exchange Act of 1934, as amended
FASB	Financial Accounting Standards Board
Fidelity	Fidelity Exploration & Production Company, a direct wholly owned subsidiary of WBI Holdings
GAAP	Accounting principles generally accepted in the United States of America
GHG	Greenhouse gas
Great Plains	Great Plains Natural Gas Co., a public utility division of the Company

2

Intermountain	Intermountain Gas Company, an indirect wholly owned subsidiary of MDU Energy Capital
JTL	JTL Group, Inc., an indirect wholly owned subsidiary of Knife River
Knife River	Knife River Corporation, a direct wholly owned subsidiary of Centennial
Knife River - Northwest	Knife River Corporation - Northwest, an indirect wholly owned subsidiary of Knife River
kWh	Kilowatt-hour
LPP	Lea Power Partners, LLC, a former indirect wholly owned subsidiary of Centennial Resources (member interests were sold in October 2006)
LWG	Lower Willamette Group
MBbls	Thousands of barrels
MBO	Thousands of barrels of oil
MBOE	Thousands of BOE
Mcf	Thousand cubic feet
MDU Brasil	MDU Brasil Ltda., an indirect wholly owned subsidiary of Centennial Resources
MDU Construction Services	MDU Construction Services Group, Inc., a direct wholly owned subsidiary of Centennial
MDU Energy Capital	MDU Energy Capital, LLC, a direct wholly owned subsidiary of the Company
MMBO	Millions of barrels of oil
MMBtu	Million Btu
MMcf	Million cubic feet
MMdk	Million decatherms
Montana-Dakota	Montana-Dakota Utilities Co., a public utility division of the Company
Montana DEQ	Montana Department of Environmental Quality
Montana First Judicial District Court	Montana First Judicial District Court, Lewis and Clark County
Montana Seventeenth Judicial District Court	Montana Seventeenth Judicial District Court, Phillips County
MTPSC	Montana Public Service Commission
MW	Megawatt
NDPSC	North Dakota Public Service Commission
New York Supreme Court	Supreme Court of the State of New York, County of New York
NGL	Natural gas liquids
NSPS	New Source Performance Standards
Oil	Includes crude oil and condensate
Omimex	Omimex Canada, Ltd.
OPUC	Oregon Public Utility Commission
Oregon DEQ	Oregon State Department of Environmental Quality
Prairielands	Prairielands Energy Marketing, Inc., an indirect wholly owned subsidiary of WBI Holdings
PRP	Potentially Responsible Party
RCRA	Resource Conservation and Recovery Act
ROD	Record of Decision
SDPUC	South Dakota Public Utilities Commission
SEC	U.S. Securities and Exchange Commission
Securities Act	Securities Act of 1933, as amended
SourceGas	SourceGas Distribution LLC
VIE	Variable interest entity
WBI Energy	WBI Energy, Inc., an indirect wholly owned subsidiary of WBI Holdings
WBI Energy Midstream	WBI Energy Midstream, LLC an indirect wholly owned subsidiary of WBI Holdings (previously Bitter Creek Pipelines, LLC, name changed effective July 1, 2012)
WBI Energy Transmission	WBI Energy Transmission, Inc., an indirect wholly owned subsidiary of WBI Holdings (previously Williston Basin Interstate Pipeline Company, name changed effective July 1, 2012)
WBI Holdings	WBI Holdings, Inc., a direct wholly owned subsidiary of Centennial
WUTC	Washington Utilities and Transportation Commission

3

INTRODUCTION

The Company is a diversified natural resource company, which was incorporated under the laws of the state of Delaware in 1924. Its principal executive offices are at 1200 West Century Avenue, P.O. Box 5650, Bismarck, North Dakota 58506-5650, telephone (701) 530-1000.

Montana-Dakota, through the electric and natural gas distribution segments, generates, transmits and distributes electricity and distributes natural gas in Montana, North Dakota, South Dakota and Wyoming. Cascade distributes natural gas in Oregon and Washington. Intermountain distributes natural gas in Idaho. Great Plains distributes natural gas in western Minnesota and southeastern North Dakota. These operations also supply related value-added services.

The Company, through its wholly owned subsidiary, Centennial, owns WBI Holdings (comprised of the pipeline and energy services and the exploration and production segments), Knife River (construction materials and contracting segment), MDU Construction Services (construction services segment), Centennial Resources and Centennial Capital (both reflected in the Other category). For more information on the Company's business segments, see Note 16.

4

INDEX

Part I -- Financial Information	Page
Consolidated Statements of Income -- Three and Six Months Ended June 30, 2013 and 2012	6
Consolidated Statements of Comprehensive Income -- Three and Six Months Ended June 30, 2013 and 2012	7
Consolidated Balance Sheets -- June 30, 2013 and 2012, and December 31, 2012	8
Consolidated Statements of Cash Flows -- Six Months Ended June 30, 2013 and 2012	9
Notes to Consolidated Financial Statements	10
Management's Discussion and Analysis of Financial Condition and Results of Operations	31
Quantitative and Qualitative Disclosures About Market Risk	49
Controls and Procedures	50
Part II -- Other Information
Legal Proceedings	51
Risk Factors	51
Mine Safety Disclosures	53
Exhibits	53
Signatures	54
Exhibit Index	55
Exhibits

5

PART I -- FINANCIAL INFORMATION

ITEM 1.  FINANCIAL STATEMENTS

MDU RESOURCES GROUP, INC.

CONSOLIDATED STATEMENTS OF INCOME

(Unaudited)

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2013			2012		2013			2012
	(In thousands, except per share amounts)
Operating revenues:
Electric, natural gas distribution and pipeline and energy services	$	227,442		$	204,455	$	651,565		$	599,533
Exploration and production, construction materials and contracting, construction services and other	833,153			763,507		1,340,633			1,221,236
Total operating revenues	1,060,595			967,962		1,992,198			1,820,769
Operating expenses:
Fuel and purchased power	18,169			15,193		39,777			33,613
Purchased natural gas sold	70,255			58,411		269,442			243,839
Operation and maintenance:
Electric, natural gas distribution and pipeline and energy services	76,627			52,717		142,730			121,115
Exploration and production, construction materials and contracting, construction services and other	661,495			623,347		1,055,511			999,497
Depreciation, depletion and amortization	95,289			83,627		188,850			169,007
Taxes, other than income	47,382			42,953		99,979			90,928
Total operating expenses	969,217			876,248		1,796,289			1,657,999
Operating income	91,378			91,714		195,909			162,770
Earnings (loss) from equity method investments	(7		)	385		(319		)	1,637
Other income	1,436			1,249		2,677			2,349
Interest expense	21,427			17,650		42,300			37,089
Income before income taxes	71,380			75,698		155,967			129,667
Income taxes	24,988			26,691		52,983			44,769
Income from continuing operations	46,392			49,007		102,984			84,898
Income (loss) from discontinued operations, net of tax (Note 10)	(59		)	5,106		(136		)	5,006
Net income	46,333			54,113		102,848			89,904
Net loss attributable to noncontrolling interest	(179		)	—		(179		)	—
Dividends declared on preferred stocks	171			171		342			343
Earnings on common stock	$	46,341		$	53,942	$	102,685		$	89,561
Earnings per common share - basic:
Earnings before discontinued operations	$	.25		$	.26	$	.54		$	.45
Discontinued operations, net of tax	—			.03		—			.02
Earnings per common share - basic	$	.25		$	.29	$	.54		$	.47
Earnings per common share - diluted:
Earnings before discontinued operations	$	.24		$	.26	$	.54		$	.45
Discontinued operations, net of tax	—			.03		—			.02
Earnings per common share - diluted	$	.24		$	.29	$	.54		$	.47
Dividends declared per common share	$	.1725		$	.1675	$	.3450		$	.3350
Weighted average common shares outstanding - basic	188,831			188,831		188,831			188,821
Weighted average common shares outstanding - diluted	189,463			189,107		189,460			189,096

The accompanying notes are an integral part of these consolidated financial statements.

6

MDU RESOURCES GROUP, INC.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2013			2012			2013			2012
	(In thousands)
Net income	$	46,333		$	54,113		$	102,848		$	89,904
Other comprehensive income (loss):
Net unrealized gain (loss) on derivative instruments qualifying as hedges:
Net unrealized gain (loss) on derivative instruments arising during the period, net of tax of $52 and $15,059 for the three months ended and $(3,116) and $13,129 for the six months ended in 2013 and 2012, respectively	254			25,773			(5,594		)	22,506
Reclassification adjustment for gain on derivative instruments included in net income, net of tax of $(322) and $(1,077) for the three months ended and $(1,948) and $(2,738) for the six months ended in 2013 and 2012, respectively	(396		)	(1,834		)	(3,168		)	(4,666		)
Net unrealized gain (loss) on derivative instruments qualifying as hedges	(142		)	23,939			(8,762		)	17,840
Net unrealized gain (loss) on available-for-sale investments:
Net unrealized loss on available-for-sale investments arising during the period, net of tax of $(77) and $(23) for the three months ended and $(100) and $(26) for the six months ended in 2013 and 2012, respectively	(142		)	(43		)	(187		)	(47		)
Reclassification adjustment for loss on available-for-sale investments included in net income, net of tax of $23 and $20 for the three months ended and $42 and $37 for the six months ended in 2013 and 2012, respectively	44			38			79			68
Net unrealized gain (loss) on available-for-sale investments	(98		)	(5		)	(108		)	21
Amortization of postretirement liability losses included in net periodic benefit cost, net of tax of $543 and $862 for the three and six months ended in 2013	424			—			1,072			—
Foreign currency translation adjustment, net of tax of $(234) and $(402) for the three months ended and $(197) and $(265) for the six months ended in 2013 and 2012, respectively	(390		)	(579		)	(302		)	(435		)
Other comprehensive income (loss)	(206		)	23,355			(8,100		)	17,426
Comprehensive income	46,127			77,468			94,748			107,330
Comprehensive loss attributable to noncontrolling interest	(179		)	—			(179		)	—
Comprehensive income attributable to common stockholders	$	46,306		$	77,468		$	94,927		$	107,330

The accompanying notes are an integral part of these consolidated financial statements.

7

MDU RESOURCES GROUP, INC.

CONSOLIDATED BALANCE SHEETS

(Unaudited)

	June 30, 2013			June 30, 2012			December 31, 2012
(In thousands, except shares and per share amounts)
ASSETS
Current assets:
Cash and cash equivalents	$	114,971		$	101,643		$	49,042
Receivables, net	734,765			654,609			678,123
Inventories	345,885			333,392			317,415
Deferred income taxes	27,959			21,451			22,846
Commodity derivative instruments	9,797			37,000			18,304
Prepayments and other current assets	58,870			85,729			42,351
Total current assets	1,292,247			1,233,824			1,128,081
Investments	106,508			99,343			103,243
Property, plant and equipment	8,454,204			8,068,177			8,107,751
Less accumulated depreciation, depletion and amortization	3,709,679			3,478,118			3,608,912
Net property, plant and equipment	4,744,525			4,590,059			4,498,839
Deferred charges and other assets:
Goodwill	636,039			635,389			636,039
Other intangible assets, net	15,312			18,656			17,129
Other	297,040			324,299			299,160
Total deferred charges and other assets	948,391			978,344			952,328
Total assets	$	7,091,671		$	6,901,570		$	6,682,491
LIABILITIES AND EQUITY
Current liabilities:
Short-term borrowings	$	31,600		$	—		$	28,200
Long-term debt due within one year	69,091			282,199			134,108
Accounts payable	411,621			379,840			388,015
Taxes payable	89,896			46,919			46,475
Dividends payable	32,745			31,800			171
Accrued compensation	44,159			37,774			48,448
Commodity derivative instruments	1,388			1,037			—
Other accrued liabilities	185,389			244,922			204,698
Total current liabilities	865,889			1,024,491			850,115
Long-term debt	1,937,663			1,383,432			1,610,867
Deferred credits and other liabilities:
Deferred income taxes	782,838			839,683			755,102
Other liabilities	810,639			833,692			818,159
Total deferred credits and other liabilities	1,593,477			1,673,375			1,573,261
Commitments and contingencies
Equity:
Preferred stocks	15,000			15,000			15,000
Common stockholders' equity:
Common stock
Authorized - 500,000,000 shares, $1.00 par value
Shares issued - 189,369,450 at June 30, 2013 and 2012 and December 31, 2012	189,369			189,369			189,369
Other paid-in capital	1,040,379			1,036,935			1,039,080
Retained earnings	1,494,419			1,612,169			1,457,146
Accumulated other comprehensive loss	(56,821		)	(29,575		)	(48,721		)
Treasury stock at cost - 538,921 shares	(3,626		)	(3,626		)	(3,626		)
Total common stockholders' equity	2,663,720			2,805,272			2,633,248
Total stockholders' equity	2,678,720			2,820,272			2,648,248
Noncontrolling interest	15,922			—			—
Total equity	2,694,642			2,820,272			2,648,248
Total liabilities and equity	$	7,091,671		$	6,901,570		$	6,682,491

The accompanying notes are an integral part of these consolidated financial statements.

8

MDU RESOURCES GROUP, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

	Six Months Ended
	June 30,
	2013			2012
	(In thousands)
Operating activities:
Net income	$	102,848		$	89,904
Income (loss) from discontinued operations, net of tax	(136		)	5,006
Income from continuing operations	102,984			84,898
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	188,850			169,007
Earnings, net of distributions, from equity method investments	1,491			1,251
Deferred income taxes	19,790			76,987
Unrealized gain on commodity derivatives	(7,215		)	(660		)
Changes in current assets and liabilities, net of acquisitions:
Receivables	(65,637		)	(2,470		)
Inventories	(29,923		)	(58,367		)
Other current assets	(18,044		)	(33,556		)
Accounts payable	18,940			(7,119		)
Other current liabilities	23,071			(45,562		)
Other noncurrent changes	(741		)	(9,410		)
Net cash provided by continuing operations	233,566			174,999
Net cash provided by (used in) discontinued operations	360			(258		)
Net cash provided by operating activities	233,926			174,741
Investing activities:
Capital expenditures	(431,439		)	(388,449		)
Acquisitions, net of cash acquired	—			(65,767		)
Net proceeds from sale or disposition of property and other	20,884			29,454
Investments	16			11,172
Net cash used in continuing operations	(410,539		)	(413,590		)
Net cash provided by discontinued operations	—			—
Net cash used in investing activities	(410,539		)	(413,590		)
Financing activities:
Issuance of short-term borrowings	29,600			—
Issuance of long-term debt	450,461			299,945
Repayment of long-term debt	(214,473		)	(58,605		)
Proceeds from issuance of common stock	—			88
Dividends paid	(32,915		)	(63,594		)
Excess tax benefit on stock-based compensation	—			26
Contribution from noncontrolling interest	10,000			—
Net cash provided by continuing operations	242,673			177,860
Net cash provided by discontinued operations	—			—
Net cash provided by financing activities	242,673			177,860
Effect of exchange rate changes on cash and cash equivalents	(131		)	(140		)
Increase (decrease) in cash and cash equivalents	65,929			(61,129		)
Cash and cash equivalents -- beginning of year	49,042			162,772
Cash and cash equivalents -- end of period	$	114,971		$	101,643

The accompanying notes are an integral part of these consolidated financial statements.

9

MDU RESOURCES GROUP, INC.

NOTES TO CONSOLIDATED

FINANCIAL STATEMENTS

June 30, 2013 and 2012

(Unaudited)

Note 1 - Basis of presentation

The accompanying consolidated interim financial statements were prepared in conformity with the basis of presentation reflected in the consolidated financial statements included in the Company's 2012 Annual Report, and the standards of accounting measurement set forth in the interim reporting guidance in the ASC and any amendments thereto adopted by the FASB. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with those appearing in the 2012 Annual Report. The information is unaudited but includes all adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Depreciation, depletion and amortization expense is reported separately on the Consolidated Statements of Income and therefore is excluded from the other line items within operating expenses. Management has also evaluated the impact of events occurring after June 30, 2013, up to the date of issuance of these consolidated interim financial statements.

Note 2 - Seasonality of operations

Some of the Company's operations are highly seasonal and revenues from, and certain expenses for, such operations may fluctuate significantly among quarterly periods. Accordingly, the interim results for particular businesses, and for the Company as a whole, may not be indicative of results for the full fiscal year.

Note 3 - Accounts receivable and allowance for doubtful accounts

Accounts receivable consists primarily of trade receivables from the sale of goods and services which are recorded at the invoiced amount net of allowance for doubtful accounts, and costs and estimated earnings in excess of billings on uncompleted contracts. The total balance of receivables past due 90 days or more was $35.1 million, $35.3 million and $34.3 million as of June 30, 2013 and 2012, and December 31, 2012, respectively.

The allowance for doubtful accounts is determined through a review of past due balances and other specific account data. Account balances are written off when management determines the amounts to be uncollectible. The Company's allowance for doubtful accounts as of June 30, 2013 and 2012, and December 31, 2012, was $10.6 million, $12.4 million and $10.8 million, respectively.

Note 4 - Inventories and natural gas in storage

Inventories, other than natural gas in storage for the Company's regulated operations, were stated at the lower of average cost or market value. Natural gas in storage for the Company's regulated operations is generally carried at average cost, or cost using the last-in, first-out method. The portion of the cost of natural gas in storage expected to be used within one year was included in inventories. Inventories consisted of:

	June 30, 2013		June 30, 2012		December 31, 2012
	(In thousands)
Aggregates held for resale	$	103,503	$	90,992	$	87,715
Asphalt oil	91,837		81,915		67,480
Materials and supplies	74,648		72,321		69,390
Merchandise for resale	27,330		30,417		31,172
Natural gas in storage (current)	14,287		26,216		29,030
Other	34,280		31,531		32,628
Total	$	345,885	$	333,392	$	317,415

The remainder of natural gas in storage, which largely represents the cost of gas required to maintain pressure levels for normal operating purposes, was included in other assets and was $48.6 million, $50.3 million, and $49.7 million at June 30, 2013 and 2012, and December 31, 2012, respectively.

10

Note 5 - Impairment of long-lived assets

During the second quarters of 2013 and 2012, the Company recognized impairments of coalbed natural gas gathering assets at the pipeline and energy services segment of $14.5 million ($9.0 million after tax) and $2.7 million ($1.7 million after tax), respectively, which are recorded in operation and maintenance expense on the Consolidated Statements of Income. The impairments are related to coalbed natural gas gathering assets located in Wyoming and Montana where there has been a significant decline in natural gas development and production activity largely due to low natural gas prices. The coalbed natural gas gathering assets were written down to fair value that was determined using the income approach. For more information on this nonrecurring fair value measurement see Note 14.

Note 6 - Earnings per common share

Basic earnings per common share were computed by dividing earnings on common stock by the weighted average number of shares of common stock outstanding during the applicable period. Diluted earnings per common share were computed by dividing earnings on common stock by the total of the weighted average number of shares of common stock outstanding during the applicable period, plus the effect of outstanding performance share awards. Common stock outstanding includes issued shares less shares held in treasury. Net income was the same for both the basic and diluted earnings per share calculations. A reconciliation of the weighted average common shares outstanding used in the basic and diluted earnings per share calculation was as follows:

	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2013	2012	2013	2012
	(In thousands)
Weighted average common shares outstanding - basic	188,831	188,831	188,831	188,821
Effect of dilutive stock options and performance share awards	632	276	629	275
Weighted average common shares outstanding - diluted	189,463	189,107	189,460	189,096
Shares excluded from the calculation of diluted earnings per share	—	—	—	—

Note 7 - Cash flow information

Cash expenditures for interest and income taxes were as follows:

	Six Months Ended
	June 30,
	2013			2012
	(In thousands)
Interest, net of amount capitalized	$	41,440		$	35,893
Income taxes paid (refunded), net	$	(2,649	)	$	2,418

Noncash investing transactions were as follows:

	June 30,
	2013		2012
	(In thousands)
Property, plant and equipment additions in accounts payable	$	77,073	$	76,505

Note 8 - New accounting standards

Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income In February 2013, the FASB issued guidance on the reporting of amounts reclassified out of accumulated other comprehensive income. This guidance requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in net income if the amount being reclassified is required to be reclassified in its entirety to net income. Entities may present this information either on the face of the statement where net income is presented or in the notes. This guidance was effective for the Company on January 1, 2013, and is to be applied prospectively. The guidance required additional disclosures, however it did not impact the Company's results of operations, financial position or cash flows.

Disclosures about Offsetting Assets and Liabilities In December 2011, the FASB issued guidance on the disclosure requirements related to balance sheet offsetting. The new disclosure requirements relate to the nature of an entity's rights of offset and related arrangements associated with its financial instruments and derivative instruments. In January 2013, the FASB issued guidance clarifying the scope of the disclosures related to balance sheet offsetting. The amendments clarify that this guidance only applies to derivative instruments, repurchase agreements and securities lending transactions that are either offset or subject to an enforceable master netting arrangement. The guidance was effective for the Company on January 1, 2013, and

11

must be applied retrospectively. The guidance required additional disclosures, however it did not impact the Company's results of operations, financial position or cash flows.

Note 9 - Comprehensive income (loss)

The after-tax changes in the components of accumulated other comprehensive loss as of June 30, 2013, were as follows:

	Net Unrealized Gain (Loss) on Derivative  Instruments  Qualifying as Hedges			Net Unrealized Gain (Loss) on Available-for-sale Investments			Postretirement  Liability Adjustment			Foreign Currency Translation Adjustment			Total Accumulated  Other Comprehensive  Loss
	(In thousands)
Balance at December 31, 2012	$	6,018		$	119		$	(54,347	)	$	(511	)	$	(48,721	)
Other comprehensive income (loss) before reclassifications	(5,594		)	(187		)	—			(302		)	(6,083		)
Amounts reclassified from accumulated other comprehensive loss	(3,168		)	79			1,072			—			(2,017		)
Net current-period other comprehensive income (loss)	(8,762		)	(108		)	1,072			(302		)	(8,100		)
Balance at June 30, 2013	$	(2,744	)	$	11		$	(53,275	)	$	(813	)	$	(56,821	)

Reclassifications out of accumulated other comprehensive loss were as follows:

	Three Months Ended			Six Months Ended			Location on Consolidated Statements of Income
	June 30, 2013			June 30, 2013
	(In thousands)
Reclassification adjustment for gain (loss) on derivative instruments included in net income
Commodity derivative instruments	$	1,382		$	5,896		Operating revenues
Interest rate derivative instruments	(664		)	(780		)	Interest expense
	718			5,116
	(322		)	(1,948		)	Income taxes
	396			3,168
Amortization of postretirement liability losses included in net periodic benefit cost	(967		)	(1,934		)	(a)
	543			862			Income taxes
	(424		)	(1,072		)
Reclassification adjustment for loss on available-for-sale investments included in net income	(67		)	(121		)	Other income
	23			42			Income taxes
	(44		)	(79		)
Total reclassifications	$	(72	)	$	2,017

(a) Included in net periodic benefit cost (credit). For more information, see Note 17.

Note 10 - Discontinued operations

In 2007, Centennial Resources sold CEM to Bicent. In connection with the sale, Centennial Resources had agreed to indemnify Bicent and its affiliates from certain third party claims arising out of or in connection with Centennial Resources' ownership or operation of CEM prior to the sale. In addition, Centennial had previously guaranteed CEM's obligations under a construction contract. The Company incurs legal expenses and has accrued liabilities related to this matter. In the second quarter of 2012, discontinued operations reflected a net benefit largely related to estimated insurance recoveries related to this matter. These items are reflected as discontinued operations in the consolidated financial statements and accompanying notes. Discontinued operations are included in the Other category. For more information, see Note 19.

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Note 11 - Equity method investments

Investments in companies in which the Company has the ability to exercise significant influence over operating and financial policies are accounted for using the equity method. The Company's equity method investments at June 30, 2013, include ECTE.

In August 2006, MDU Brasil acquired ownership interests in the Brazilian Transmission Lines. The electric transmission lines are primarily in northeastern and southern Brazil. The transmission contracts provide for revenues denominated in the Brazilian Real, annual inflation adjustments and change in tax law adjustments. The functional currency for the Brazilian Transmission Lines is the Brazilian Real.

In 2009, multiple sales agreements were signed for the Company to sell its ownership interest in the Brazilian Transmission Lines. In November 2010, the Company completed the sale of its entire ownership interest in ENTE and ERTE and 59.96 percent of the Company's ownership interest in ECTE. The remaining interest in ECTE is being purchased over a four-year period. In August 2012 and November 2011, the Company completed the sale of one-fourth of the remaining interest in each year. Alusa, CEMIG and CELESC hold the remaining ownership interests in ECTE.

At June 30, 2013 and 2012, and December 31, 2012, the equity method investments had total assets of $114.8 million, $104.4 million and $129.0 million, respectively, and long-term debt of $56.2 million, $30.3 million and $65.5 million, respectively. The Company's investment in its equity method investments was approximately $5.5 million, $7.4 million and $6.9 million, including undistributed earnings of $2.0 million, $2.3 million and $3.4 million, at June 30, 2013 and 2012, and December 31, 2012, respectively.

Note 12 - Goodwill and other intangible assets

The changes in the carrying amount of goodwill were as follows:

Six Months Ended June 30, 2013	Balance as of January 1, 2013*		Goodwill Acquired During the Year		Balance as of June 30, 2013*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	104,276		—		104,276
Total	$	636,039	$	—	$	636,039

* Balance is presented net of accumulated impairment of $12.3 million at the pipeline and energy services segment, which occurred in prior periods.

Six Months Ended June 30, 2012	Balance as of January 1, 2012*		Goodwill Acquired During the Year**		Balance as of June 30, 2012*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	103,168		458		103,626
Total	$	634,931	$	458	$	635,389

* Balance is presented net of accumulated impairment of $12.3 million at the pipeline and energy services segment, which occurred in prior periods.

** Includes contingent consideration that was not material related to an acquisition in a prior period.

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Year Ended December 31, 2012	Balance as of January 1, 2012*		Goodwill Acquired During the Year**		Balance as of December 31, 2012*
	(In thousands)
Natural gas distribution	$	345,736	$	—	$	345,736
Pipeline and energy services	9,737		—		9,737
Construction materials and contracting	176,290		—		176,290
Construction services	103,168		1,108		104,276
Total	$	634,931	$	1,108	$	636,039

  * Balance is presented net of accumulated impairment of $12.3 million at the pipeline and energy services segment, which occurred in prior periods.

** Includes contingent consideration that was not material related to an acquisition in a prior period.

Other amortizable intangible assets were as follows:

	June 30, 2013			June 30, 2012			December 31, 2012
	(In thousands)
Customer relationships	$	21,310		$	21,010		$	21,310
Accumulated amortization	(12,715		)	(10,690		)	(11,701		)
	8,595			10,320			9,609
Noncompete agreements	6,186			7,086			7,236
Accumulated amortization	(4,557		)	(5,057		)	(5,326		)
	1,629			2,029			1,910
Other	10,979			10,978			10,979
Accumulated amortization	(5,891		)	(4,671		)	(5,369		)
	5,088			6,307			5,610
Total	$	15,312		$	18,656		$	17,129

Amortization expense for amortizable intangible assets for the three and six months ended June 30, 2013, was $1.0 million and $1.8 million, respectively. Amortization expense for amortizable intangible assets for the three and six months ended June 30, 2012, was $1.0 million and $1.9 million, respectively. Estimated amortization expense for amortizable intangible assets is $3.7 million in 2013, $3.5 million in 2014, $2.6 million in 2015, $2.2 million in 2016, $1.9 million in 2017 and $3.2 million thereafter.

Note 13 - Derivative instruments

The Company's policy allows the use of derivative instruments as part of an overall energy price, foreign currency and interest rate risk management program to efficiently manage and minimize commodity price, foreign currency and interest rate risk. As of June 30, 2013, the Company had no outstanding foreign currency hedges. The following information should be read in conjunction with Notes 1 and 7 in the Company's Notes to Consolidated Financial Statements in the 2012 Annual Report.

The fair value of derivative instruments must be estimated as of the end of each reporting period and is recorded on the Consolidated Balance Sheets as an asset or a liability.

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Cascade

Cascade has historically utilized natural gas swap agreements to manage a portion of its regulated natural gas supply portfolio in order to manage fluctuations in the price of natural gas related to core customers in accordance with authority granted by the WUTC and OPUC. Core customers consist of residential, commercial and smaller industrial customers. As of June 30, 2013 and December 31, 2012, Cascade has no outstanding swap agreements. As of June 30, 2012, Cascade held a natural gas swap agreement with total forward notional volumes of 123,000 MMBtu. Periodic changes in the fair market value of the derivative instruments are recorded on the Consolidated Balance Sheets as a regulatory asset or a regulatory liability, and settlements of these arrangements are expected to be recovered through the purchased gas cost adjustment mechanism. Gains and losses on the settlements of these derivative instruments are recorded as a component of purchased natural gas sold on the Consolidated Statements of Income as they are recovered through the purchased gas cost adjustment mechanism. Under the terms of these arrangements, Cascade either pays or receives settlement payments based on the difference between the fixed strike price and the monthly index price applicable to each contract. For the three and six months ended June 30, 2012, the change in the fair market value of the derivative instrument of $261,000 and $209,000, respectively, was recorded as a decrease to regulatory assets.

Cascade's derivative instrument contains a cross-default provision that states that if Cascade fails to pay certain of its indebtedness, in excess of specified amounts, the counterparty may require early settlement or termination of the derivative instrument in a liability position. The fair value of Cascade's derivative instrument with the credit-risk-related contingent feature that was in a liability position at June 30, 2012, was $228,000. The aggregate fair value of assets that would have been needed to settle the instrument immediately if the credit-risk-related contingent feature were triggered on June 30, 2012, was $228,000.

Fidelity

At June 30, 2013 and 2012, and December 31, 2012, Fidelity held oil swap and collar agreements with total forward notional volumes of 3.1 million, 3.7 million and 2.6 million Bbl, respectively, and natural gas swap agreements with total forward notional volumes of 21.4 million, 9.1 million  and 11.0 million MMBtu, respectively. In addition, at June 30, 2012, Fidelity held natural gas basis swap agreements with total forward notional volumes of 1.7 million MMBtu. Fidelity utilizes these derivative instruments to manage a portion of the market risk associated with fluctuations in the price of oil and natural gas and basis differentials on its forecasted sales of oil and natural gas production.

Effective April 1, 2013, Fidelity elected to de-designate all commodity derivative contracts previously designated as cash flow hedges and elected to discontinue hedge accounting prospectively for all of its commodity derivative instruments. When the criteria for hedge accounting is not met or when hedge accounting is not elected, realized gains and losses and unrealized gains and losses are both recorded in operating revenues on the Consolidated Statements of Income. As a result of discontinuing hedge accounting on commodity derivative instruments, gains and losses on the oil and natural gas derivative instruments remain in accumulated other comprehensive income (loss) as of the de-designation date and are reclassified into earnings in future periods as the underlying hedged transactions affect earnings. At April 1, 2013, accumulated other comprehensive income (loss) included $1.8 million of unrealized gains, representing the mark-to-market value of the Company's commodity derivative instruments that qualified as cash flow hedges as of the balance sheet date. The Company expects to reclassify into earnings from accumulated other comprehensive income (loss) the remaining value related to de-designating commodity derivative instruments over the next 18 months.

Prior to April 1, 2013, changes in the fair value attributable to the effective portion of the hedging instruments, net of tax, were recorded in stockholders' equity as a component of accumulated other comprehensive income (loss). To the extent that the hedges were not effective or did not qualify for hedge accounting, the ineffective portion of the changes in fair market value was recorded directly in earnings. Gains and losses on the oil and natural gas derivative instruments were reclassified from accumulated other comprehensive income (loss) into operating revenues on the Consolidated Statement of Income at the date the oil and natural gas quantities were settled.

Centennial

As of June 30, 2013, Centennial had no outstanding interest rate swap agreements. At June 30, 2012 and December 31, 2012, Centennial held interest rate swap agreements with total notional amounts of $60.0 million and $50.0 million, respectively, which were designated as cash flow hedging instruments. Centennial entered into these interest rate derivative instruments to manage a portion of its interest rate exposure on the forecasted issuance of long-term debt.

Changes in the fair value attributable to the effective portion of hedging instruments, net of tax, are recorded in stockholders' equity as a component of accumulated other comprehensive income (loss). To the extent that the hedges are not effective, the ineffective portion of the changes in fair market value is recorded directly in earnings. Gains and losses on the interest rate

15

derivatives are reclassified from accumulated other comprehensive income (loss) into interest expense on the Consolidated Statements of Income in the same period the hedged item affects earnings.

Fidelity and Centennial

There were no components of the derivative instruments' gain or loss excluded from the assessment of hedge effectiveness. Gains and losses must be reclassified into earnings as a result of the discontinuance of cash flow hedges if it is probable that the original forecasted transactions will not occur, and there were no such reclassifications.

The gains and losses on derivative instruments were as follows:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2013			2012			2013			2012
	(In thousands)
Commodity derivatives designated as cash flow hedges:
Amount of gain (loss) recognized in accumulated other comprehensive loss (effective portion), net of tax	$	—		$	28,018		$	(6,154	)	$	23,863
Amount of (gain) loss reclassified from accumulated other comprehensive loss into operating revenues (effective portion), net of tax	(871		)	(1,840		)	(3,714		)	(4,687		)
Amount of gain (loss) recognized in operating revenues (ineffective portion), before tax	—			3,863			(1,422		)	(388		)
Interest rate derivatives designated as cash flow hedges:
Amount of gain (loss) recognized in accumulated other comprehensive loss (effective portion), net of tax	254			(2,245		)	560			(1,357		)
Amount of loss reclassified from accumulated other comprehensive loss into interest expense (effective portion), net of tax	475			6			546			21
Amount of loss recognized in interest expense (ineffective portion), before tax	(610		)	—			(769		)	—
Commodity derivatives not designated as hedging instruments:
Amount of gain recognized in operating revenues, before tax	13,047			993			8,637			1,048

Based on June 30, 2013, fair values, over the next 12 months net losses of approximately $1.5 million (after tax) are estimated to be reclassified from accumulated other comprehensive income (loss) into earnings, as the hedged transactions affect earnings.

Certain of Fidelity's derivative instruments contain cross-default provisions that state if Fidelity or any of its affiliates fail to pay certain of their indebtedness, in excess of specified amounts, the counterparties may require early settlement or termination of the derivative instruments in liability positions. The aggregate fair value of Fidelity's derivative instruments with credit-risk-related contingent features that are in a liability position at June 30, 2013 and 2012, and December 31, 2012, were $1.4 million, $7.8 million and $6.3 million, respectively. The aggregate fair value of assets that would have been needed to settle the instruments immediately if the credit-risk-related contingent features were triggered on June 30, 2013 and 2012, and December 31, 2012, were $1.4 million, $7.8 million and $6.3 million, respectively.

16

The location and fair value of the gross amount of the Company's derivative instruments on the Consolidated Balance Sheets were as follows:

Asset Derivatives	Location on Consolidated Balance Sheets	Fair Value at June 30, 2013		Fair Value at June 30, 2012		Fair Value at December 31, 2012
		(In thousands)
Designated as hedges:
Commodity derivatives	Commodity derivative instruments	$	—	$	36,360	$	18,084
	Other assets - noncurrent	—		11,445		—
		—		47,805		18,084
Not designated as hedges:
Commodity derivatives	Commodity derivative instruments	9,797		640		220
	Other assets - noncurrent	1,447		212		—
		11,244		852		220
Total asset derivatives		$	11,244	$	48,657	$	18,304

Liability Derivatives	Location on Consolidated Balance Sheets	Fair Value at June 30, 2013		Fair Value at June 30, 2012		Fair Value at December 31, 2012
		(In thousands)
Designated as hedges:
Commodity derivatives	Commodity derivative instruments	$	—	$	789	$	—
Interest rate derivatives	Other accrued liabilities	—		6,963		6,255
		—		7,752		6,255
Not designated as hedges:
Commodity derivatives	Commodity derivative instruments	1,388		248		—
		1,388		248		—
Total liability derivatives		$	1,388	$	8,000	$	6,255

All of the Company's commodity and interest rate derivative instruments at June 30, 2013 and 2012, and December 31, 2012, were subject to legally enforceable master netting agreements. However, the Company's policy is to not offset fair value amounts for derivative instruments and, as a result, the Company's derivative assets and liabilities are presented gross on the Consolidated Balance Sheets. The gross derivative assets and liabilities (excluding settlement receivables and payables that may be subject to the same master netting agreements) presented on the Consolidated Balance Sheets and the amount eligible for offset under the master netting agreements is presented in the following table:

June 30, 2013	Gross Amounts Recognized on the Consolidated Balance Sheets		Gross Amounts Not Offset on the Consolidated Balance Sheets			Net
	(In thousands)
Assets:
Commodity derivatives	$	11,244	$	(1,388	)	$	9,856
Total assets	$	11,244	$	(1,388	)	$	9,856
Liabilities:
Commodity derivatives	$	1,388	$	(1,388	)	$	—
Total liabilities	$	1,388	$	(1,388	)	$	—

17

June 30, 2012	Gross Amounts Recognized on the Consolidated Balance Sheets		Gross Amounts Not Offset on the Consolidated Balance Sheets			Net
	(In thousands)
Assets:
Commodity derivatives	$	48,657	$	(809	)	$	47,848
Total assets	$	48,657	$	(809	)	$	47,848
Liabilities:
Commodity derivatives	$	1,037	$	(809	)	$	228
Interest rate derivatives	6,963		—			6,963
Total liabilities	$	8,000	$	(809	)	$	7,191

December 31, 2012	Gross Amounts Recognized on the Consolidated Balance Sheets		Gross Amounts Not Offset on the Consolidated Balance Sheets		Net
	(In thousands)
Assets:
Commodity derivatives	$	18,304	$	—	$	18,304
Total assets	$	18,304	$	—	$	18,304
Liabilities:
Interest rate derivatives	$	6,255	$	—	$	6,255
Total liabilities	$	6,255	$	—	$	6,255

Note 14 - Fair value measurements

The Company measures its investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income. The Company anticipates using these investments, which consist of an insurance contract, to satisfy its obligations under its unfunded, nonqualified benefit plans for executive officers and certain key management employees, and invests in these fixed-income and equity securities for the purpose of earning investment returns and capital appreciation. These investments, which totaled $54.0 million, $46.0 million and $48.9 million, as of June 30, 2013 and 2012, and December 31, 2012, respectively, are classified as Investments on the Consolidated Balance Sheets. The net unrealized gains on these investments were $700,000 and $5.1 million for the three and six months ended June 30, 2013, respectively. The net unrealized loss on these investments was $2.7 million for the three months ended June 30, 2012, and the net unrealized gain on these investments was $2.2 million for the six months ended June 30, 2012. The change in fair value, which is considered part of the cost of the plan, is classified in operation and maintenance expense on the Consolidated Statements of Income.

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The Company did not elect the fair value option, which records gains and losses in income, for its remaining available-for-sale securities, which include mortgage-backed securities and U.S. Treasury securities. These available-for-sale securities are recorded at fair value and are classified as Investments on the Consolidated Balance Sheets. Unrealized gains or losses are recorded in accumulated other comprehensive income (loss). Details of available-for-sale securities were as follows:

June 30, 2013	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Insurance contract	$	37,270	$	16,769	$	—		$	54,039
Mortgage-backed securities	8,035		58		(41		)	8,052
U.S. Treasury securities	1,920		15		(15		)	1,920
Total	$	47,225	$	16,842	$	(56	)	$	64,011

June 30, 2012	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Insurance contract	$	37,250	$	8,709	$	—		$	45,959
Mortgage-backed securities	8,130		128		(5		)	8,253
U.S. Treasury securities	1,958		37		(1		)	1,994
Total	$	47,338	$	8,874	$	(6	)	$	56,206

December 31, 2012	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
Insurance contract	$	37,250	$	11,648	$	—		$	48,898
Mortgage-backed securities	8,054		144		(3		)	8,195
U.S. Treasury securities	1,763		43		—			1,806
Total	$	47,067	$	11,835	$	(3	)	$	58,899

The fair value of the Company's money market funds approximates cost.

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The ASC establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs.

The estimated fair values of the Company's assets and liabilities measured on a recurring basis are determined using the market approach.

The Company's Level 2 money market funds consist of investments in short-term unsecured promissory notes and the value is based on comparable market transactions taking into consideration the credit quality of the issuer. The estimated fair value of the Company's Level 2 mortgage-backed securities and U.S. Treasury securities are based on comparable market transactions, other observable inputs or other sources, including pricing from outside sources.

The estimated fair value of the Company's Level 2 insurance contract is based on contractual cash surrender values that are determined primarily by investments in managed separate accounts of the insurer. These amounts approximate fair value. The managed separate accounts are valued based on other observable inputs or corroborated market data.

The estimated fair value of the Company's Level 2 commodity derivative instruments is based upon futures prices, volatility and time to maturity, among other things. Counterparty statements are utilized to determine the value of the commodity derivative instruments and are reviewed and corroborated using various methodologies and significant observable inputs. The Company's and the counterparties' nonperformance risk is also evaluated.

The estimated fair value of the Company's Level 2 interest rate derivative instruments is measured using quoted market prices or pricing models using prevailing market interest rates as of the measurement date. Counterparty statements are utilized to

19

determine the value of the interest rate derivative instruments and are reviewed and corroborated using various methodologies and significant observable inputs. The Company's and the counterparties' nonperformance risk is also evaluated.

Though the Company believes the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value. For the three and six months ended June 30, 2013 and 2012, there were no transfers between Levels 1 and 2.

The Company's assets and liabilities measured at fair value on a recurring basis are as follows:

	Fair Value Measurements at June 30, 2013, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at June 30, 2013
	(In thousands)
Assets:
Money market funds	$	—	$	29,902	$	—	$	29,902
Available-for-sale securities:
Insurance contract*	—		54,039		—		54,039
Mortgage-backed securities	—		8,052		—		8,052
U.S. Treasury securities	—		1,920		—		1,920
Commodity derivative instruments	—		11,244		—		11,244
Total assets measured at fair value	$	—	$	105,157	$	—	$	105,157
Liabilities:
Commodity derivative instruments	$	—	$	1,388	$	—	$	1,388
Total liabilities measured at fair value	$	—	$	1,388	$	—	$	1,388

*  The insurance contract invests approximately 28 percent in common stock of mid-cap companies, 28 percent in common stock of small-cap companies, 28 percent in common stock of large-cap companies and 16 percent in fixed-income and other investments.

	Fair Value Measurements at June 30, 2012, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Balance at June 30, 2012
	(In thousands)
Assets:
Money market funds	$	—	$	21,054	$	—	$	21,054
Available-for-sale securities:
Insurance contract*	—		45,959		—		45,959
Mortgage-backed securities	—		8,253		—		8,253
U.S. Treasury securities	—		1,994		—		1,994
Commodity derivative instruments	—		48,657		—		48,657
Total assets measured at fair value	$	—	$	125,917	$	—	$	125,917
Liabilities:
Commodity derivative instruments	$	—	$	1,037	$	—	$	1,037
Interest rate derivative instruments	—		6,963		—		6,963
Total liabilities measured at fair value	$	—	$	8,000	$	—	$	8,000

*  The insurance contract invests approximately 28 percent in common stock of mid-cap companies, 28 percent in common stock of small-cap companies, 29 percent in common stock of large-cap companies and 15 percent in fixed-income and other investments.

20

	Fair Value Measurements at December 31, 2012, Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs  (Level 3)		Balance at December 31, 2012
	(In thousands)
Assets:
Money market funds	$	—	$	24,240	$	—	$	24,240
Available-for-sale securities:
Insurance contract*	—		48,898		—		48,898
Mortgage-backed securities	—		8,195		—		8,195
U.S. Treasury securities	—		1,806		—		1,806
Commodity derivative instruments	—		18,304		—		18,304
Total assets measured at fair value	$	—	$	101,443	$	—	$	101,443
Liabilities:
Interest rate derivative instruments	$	—	$	6,255	$	—	$	6,255
Total liabilities measured at fair value	$	—	$	6,255	$	—	$	6,255

* The insurance contract invests approximately 28 percent in common stock of mid-cap companies, 28 percent in common stock of small-cap companies, 29 percent in common stock of large-cap companies and 15 percent in fixed-income and other investments.

The Company applies the provisions of the fair value measurement standard to its nonrecurring, non-financial measurements, including long-lived asset impairments. These assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. The Company reviews the carrying value of its long-lived assets, excluding goodwill and oil and natural gas properties, whenever events or changes in circumstances indicate that such carrying amounts may not be recoverable. During the second quarters of 2013 and 2012, coalbed natural gas gathering assets were reviewed for impairment and found to be impaired and were written down to their estimated fair value using the income approach. Under this approach, fair value is determined by using the present value of future estimated cash flows. The factors used to determine the estimated future cash flows include, but are not limited to, internal estimates of gathering revenue, future commodity prices and operating costs and equipment salvage values. The estimated cash flows are discounted using a rate that approximates the weighted average cost of capital of a market participant. These fair value inputs are not typically observable. At June 30, 2012, certain coalbed natural gas gathering assets were written down to the nonrecurring fair value measurement of $2.5 million. At June 30, 2013, additional coalbed natural gas gathering assets were written down to the nonrecurring fair value measurement of $9.7 million. The fair value of these coalbed natural gas gathering assets have been categorized as Level 3 (Significant Unobservable Inputs) in the fair value hierarchy.

The Company's long-term debt is not measured at fair value on the Consolidated Balance Sheets and the fair value is being provided for disclosure purposes only. The fair value was based on discounted future cash flows using current market interest rates. The estimated fair value of the Company's Level 2 long-term debt was as follows:

	Carrying Amount		Fair Value
	(In thousands)
Long-term debt at June 30, 2013	$	2,006,754	$	2,090,208
Long-term debt at June 30, 2012	$	1,665,631	$	1,839,430
Long-term debt at December 31, 2012	$	1,744,975	$	1,888,135

The carrying amounts of the Company's remaining financial instruments included in current assets and current liabilities approximate their fair values.

Note 15 - Income taxes

In connection with the income tax examination for the 2007 through 2009 tax years, the Company recorded income tax expense of $2.2 million for unrecognized tax positions in the first quarter of 2012.

In addition, the Company had a reduction of deferred income tax expense of $2.5 million in the first quarter of 2012, due to a deferred income tax rate reduction related to state income tax apportionment.

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It is likely that substantially all of the unrecognized tax benefits of $14.9 million, as well as interest, at June 30, 2013, will be settled in the next 12 months due to the anticipated settlement of federal and state audits.

Note 16 - Business segment data

The Company's reportable segments are those that are based on the Company's method of internal reporting, which generally segregates the strategic business units due to differences in products, services and regulation. The internal reporting of these operating segments is defined based on the reporting and review process used by the Company's chief executive officer. The vast majority of the Company's operations are located within the United States. The Company also has an investment in a foreign country, which consists of Centennial Resources' equity method investment in ECTE.

The electric segment generates, transmits and distributes electricity in Montana, North Dakota, South Dakota and Wyoming. The natural gas distribution segment distributes natural gas in those states as well as in Idaho, Minnesota, Oregon and Washington. These operations also supply related value-added services.

The pipeline and energy services segment provides natural gas transportation, underground storage, processing and gathering services, as well as oil gathering, through regulated and nonregulated pipeline systems primarily in the Rocky Mountain and northern Great Plains regions of the United States. This segment is constructing a diesel topping plant to refine crude oil and also provides cathodic protection and other energy-related services.

The exploration and production segment is engaged in oil and natural gas acquisition, exploration, development and production activities in the Rocky Mountain and Mid-Continent regions of the United States and in and around the Gulf of Mexico.

The construction materials and contracting segment mines aggregates and markets crushed stone, sand, gravel and related construction materials, including ready-mixed concrete, cement, asphalt, liquid asphalt and other value-added products. It also performs integrated contracting services. This segment operates in the central, southern and western United States and Alaska and Hawaii.

The construction services segment specializes in constructing and maintaining electric and communication lines, gas pipelines, fire suppression systems, and external lighting and traffic signalization equipment. This segment also provides utility excavation services and inside electrical wiring, cabling and mechanical services, sells and distributes electrical materials, and manufactures and distributes specialty equipment.

The Other category includes the activities of Centennial Capital, which insures various types of risks as a captive insurer for certain of the Company's subsidiaries. The function of the captive insurer is to fund the deductible layers of the insured companies' general liability and automobile liability coverages. Centennial Capital also owns certain real and personal property. The Other category also includes Centennial Resources' equity method investment in ECTE.

The information below follows the same accounting policies as described in Note 1 of the Company's Notes to Consolidated Financial Statements in the 2012 Annual Report. Information on the Company's businesses was as follows:

Three Months Ended June 30, 2013	External Operating Revenues		Inter- segment Operating Revenues			Earnings on Common Stock
	(In thousands)
Electric	$	56,981	$	—		$	4,410
Natural gas distribution	127,584		—			(5,893		)
Pipeline and energy services	42,877		7,999			(6,395		)
	227,442		7,999			(7,878		)
Exploration and production	137,053		12,556			32,995
Construction materials and contracting	418,345		12,958			10,025
Construction services	277,259		2,340			12,915
Other	496		1,839			340
	833,153		29,693			56,275
Intersegment eliminations	—		(37,692		)	(2,056		)
Total	$	1,060,595	$	—		$	46,341

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Three Months Ended June 30, 2012	External Operating Revenues		Inter- segment Operating Revenues			Earnings on Common Stock
	(In thousands)
Electric	$	52,955	$	—		$	4,419
Natural gas distribution	116,844		—			(6,411		)
Pipeline and energy services	34,656		8,937			15,851
	204,455		8,937			13,859
Exploration and production	100,232		5,711			17,957
Construction materials and contracting	438,963		3,097			7,791
Construction services	223,858		219			8,684
Other	454		2,028			5,651
	763,507		11,055			40,083
Intersegment eliminations	—		(19,992		)	—
Total	$	967,962	$	—		$	53,942

Six Months Ended June 30, 2013	External Operating Revenues		Inter- segment Operating Revenues			Earnings on Common Stock
	(In thousands)
Electric	$	121,635	$	—		$	14,235
Natural gas distribution	459,337		—			26,624
Pipeline and energy services	70,593		26,717			(4,064		)
	651,565		26,717			36,795
Exploration and production	252,415		22,369			53,279
Construction materials and contracting	580,323		17,251			(10,557		)
Construction services	507,065		3,914			24,579
Other	830		3,657			645
	1,340,633		47,191			67,946
Intersegment eliminations	—		(73,908		)	(2,056		)
Total	$	1,992,198	$	—		$	102,685

Six Months Ended June 30, 2012	External Operating Revenues		Inter- segment Operating Revenues			Earnings on Common Stock
	(In thousands)
Electric	$	110,918	$	—		$	11,978
Natural gas distribution	424,733		—			19,097
Pipeline and energy services	63,882		29,347			18,611
	599,533		29,347			49,686
Exploration and production	188,727		17,038			30,887
Construction materials and contracting	588,232		3,248			(17,141		)
Construction services	442,010		244			20,087
Other	2,267		2,355			6,042
	1,221,236		22,885			39,875
Intersegment eliminations	—		(52,232		)	—
Total	$	1,820,769	$	—		$	89,561

Earnings from electric, natural gas distribution and pipeline and energy services are substantially all from regulated operations. Earnings from exploration and production, construction materials and contracting, construction services and other are all from nonregulated operations.

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Note 17 - Employee benefit plans

The Company has noncontributory defined benefit pension plans and other postretirement benefit plans for certain eligible employees. Components of net periodic benefit cost for the Company's pension and other postretirement benefit plans were as follows:

							Other
							Postretirement
	Pension Benefits						Benefits
Three Months Ended June 30,	2013			2012			2013			2012
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	37		$	350		$	334		$	461
Interest cost	4,106			4,262			667			1,038
Expected return on assets	(4,875		)	(5,845		)	(1,065		)	(1,201		)
Amortization of prior service cost (credit)	18			(21		)	(364		)	(272		)
Amortization of net actuarial loss	1,716			2,102			407			887
Amortization of net transition obligation	—			—			—			531
Net periodic benefit cost, including amount capitalized	1,002			848			(21		)	1,444
Less amount capitalized	158			196			61			183
Net periodic benefit cost (credit)	$	844		$	652		$	(82	)	$	1,261
							Other
							Postretirement
	Pension Benefits						Benefits
Six Months Ended June 30,	2013			2012			2013			2012
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	77		$	695		$	838		$	873
Interest cost	8,124			8,816			1,607			2,181
Expected return on assets	(9,958		)	(11,731		)	(2,172		)	(2,445		)
Amortization of prior service cost (credit)	36			(42		)	(728		)	(544		)
Amortization of net actuarial loss	3,580			3,783			1,078			1,413
Amortization of net transition obligation	—			—			—			1,063
Net periodic benefit cost, including amount capitalized	1,859			1,521			623			2,541
Less amount capitalized	268			430			90			321
Net periodic benefit cost	$	1,591		$	1,091		$	533		$	2,220

In 2010, all benefit and service accruals for nonunion and certain union plans were frozen. In 2011 and effective September 30, 2012, all benefit and service accruals for certain additional union employees were frozen. These employees are eligible to receive additional defined contribution plan benefits.

In addition to the qualified plan defined pension benefits reflected in the table, the Company has unfunded, nonqualified benefit plans for executive officers and certain key management employees that generally provide for defined benefit payments at age 65 following the employee's retirement or to their beneficiaries upon death for a 15-year period. The Company's net periodic benefit cost for this plan for the three and six months ended June 30, 2013, was $1.8 million and $3.6 million, respectively. The company's net periodic benefit cost for this plan for the three and six months ended June 30, 2012, was $2.0 million and $4.1 million, respectively.

In 2012, the Company modified health care coverage for certain retirees. Effective January 1, 2013, post-65 coverage is replaced by a fixed-dollar subsidy for certain retirees and spouses to be used to purchase individual insurance through an exchange.

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Note 18 - Regulatory matters and revenues subject to refund

On September 26, 2012, Montana-Dakota filed an application with the MTPSC for a natural gas rate increase. Montana-Dakota requested a total increase of $3.5 million annually or approximately 5.9 percent above current rates. The requested increase includes the costs associated with the increased investment in facilities, including ongoing investment in new and replacement distribution facilities, the landfill gas production facility, a region operations building, automated meter reading and a new customer billing system. Montana-Dakota requested an interim increase, subject to refund, of $1.7 million or approximately 2.9 percent. On April 12, 2013, the MTPSC issued an interim order authorizing an interim increase of $850,000 annually to be effective with service rendered on or after April 15, 2013, subject to refund. A hearing began on August 5, 2013.

On December 21, 2012, Montana-Dakota filed an application with the SDPUC for a natural gas rate increase. Montana-Dakota requested a total increase of $1.5 million annually or approximately 3.3 percent above current rates. The requested increase includes the costs associated with the increased investment in facilities, including ongoing investment in new and replacement distribution facilities, the landfill gas production facility, an operations building, automated meter reading and a new customer billing system. On June 19, 2013, Montana-Dakota filed a notice of intent to implement an interim rate increase of $1.5 million effective with service rendered on or after July 22, 2013. A hearing is scheduled to begin October 29, 2013.

On February 11, 2013, Montana-Dakota filed an application with the NDPSC for approval of an environmental cost recovery rider for recovery of Montana-Dakota's share of the costs resulting from the environmental retrofit required to be installed at the Big Stone Station. The costs proposed to be recovered are associated with the ongoing construction costs for the installation of the BART air-quality control system. On February 27, 2013, the NDPSC suspended the filing pending further review. On May 31, 2013, Montana-Dakota filed revisions to its filing to reflect revised budget amounts. A hearing is scheduled to begin September 16, 2013.

On June 14, 2013, Montana-Dakota filed for an advance determination of prudence with the NDPSC to add filterable particulate matter pollution control equipment at Montana-Dakota's Lewis & Clark generating station to comply with the Mercury and Air Toxics Standards rule, projected to be completed in 2016. Project cost is estimated to be $26.1 million.

Note 19 - Contingencies

The Company is party to claims and lawsuits arising out of its business and that of its consolidated subsidiaries. The Company accrues a liability for those contingencies when the incurrence of a loss is probable and the amount can be reasonably estimated. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. The Company does not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated or when the liability is believed to be only reasonably possible or remote. For contingencies where an unfavorable outcome is probable or reasonably possible and which are material, the Company discloses the nature of the contingency and, where feasible, an estimate of the possible loss. The Company had accrued liabilities of $32.9 million, $48.1 million and $22.5 million for contingencies, including litigation and environmental matters, as of June 30, 2013 and 2012, and December 31, 2012, respectively, which include amounts that may have been accrued for matters discussed in Litigation and Environmental matters within this note.

Litigation

Guarantee Obligation Under a Construction Contract Centennial guaranteed CEM's obligations under a construction contract with LPP for a 550-MW combined-cycle electric generating facility near Hobbs, New Mexico. Centennial Resources sold CEM in July 2007 to Bicent. In February 2009, Centennial received a Notice and Demand from LPP under the guarantee agreement alleging that CEM did not meet certain of its obligations under the construction contract and demanding that Centennial indemnify LPP against all losses, damages, claims, costs, charges and expenses arising from CEM's alleged failures. In December 2009, LPP submitted a demand for arbitration of its dispute with CEM to the American Arbitration Association seeking compensatory damages of $149.7 million. An arbitration award was issued January 13, 2012, awarding LPP $22.0 million. Centennial subsequently received a demand from LPP for payment of the arbitration award plus interest and attorneys' fees. An accrual related to the guarantee as a result of the arbitration award was recorded in discontinued operations on the Consolidated Statement of Income in the fourth quarter of 2011. CEM filed a petition with the New York Supreme Court to vacate the arbitration award in favor of LPP. On October 19, 2012, Centennial moved to intervene in the New York Supreme Court action to vacate the arbitration award and also filed a complaint with the New York Supreme Court seeking a declaration that LPP is not entitled to indemnification from Centennial under the guaranty for the arbitration award. The New York Supreme Court granted CEM's petition to vacate the arbitration award on November 20, 2012, and entered an order and judgment to that effect on June 5, 2013. LPP appealed the order and judgment. Due to the vacation of the arbitration award, the Company no longer believes the loss related to this matter to be probable and thus the liability that was previously recorded in 2011 was reversed in the fourth quarter of 2012. We believe that it is reasonably possible that a loss related to this matter could result if LPP is successful in its appeal, the arbitration award is affirmed and LPP continues to assert its demand against

25

Centennial under the guarantee for payment of the arbitration award, attorneys' fees and interest. For more information regarding discontinued operations, see Note 10.

Construction MaterialsUntil the fall of 2011 when it discontinued active mining operations at the pit, JTL operated the Target Range Gravel Pit in Missoula County, Montana under a 1975 reclamation contract pursuant to the Montana Opencut Mining Act. In September 2009, the Montana DEQ sent a letter asserting JTL was in violation of the Montana Opencut Mining Act by conducting mining operations outside a permitted area. JTL filed a complaint in Montana First Judicial District Court in June 2010, seeking a declaratory order that the reclamation contract is a valid permit under the Montana Opencut Mining Act. The Montana DEQ filed an answer and counterclaim to the complaint in August 2011, alleging JTL was in violation of the Montana Opencut Mining Act and requesting imposition of penalties of not more than $3.7 million plus not more than $5,000 per day from the date of the counterclaim. The Company believes the operation of the Target Range Gravel Pit was conducted under a valid permit; however, the imposition of civil penalties is reasonably possible. The Company filed an application for amendment of its opencut mining permit and intends to resolve this matter through settlement or continuation of the Montana First Judicial District Court litigation.

Natural Gas Gathering Operations In January 2010, SourceGas filed an application with the Colorado State District Court to compel WBI Energy Midstream to arbitrate a dispute regarding operating pressures under a natural gas gathering contract on one of WBI Energy Midstream's pipeline gathering systems in Montana. WBI Energy Midstream resisted the application and sought a declaratory order interpreting the gathering contract. In May 2010, the Colorado State District Court granted the application and ordered WBI Energy Midstream into arbitration. An arbitration hearing was held in August 2010. In October 2010, the arbitration panel issued an award in favor of SourceGas for approximately $26.6 million. As a result, WBI Energy Midstream, which is included in the pipeline and energy services segment, recorded a $26.6 million charge ($16.5 million after tax) in the third quarter of 2010. On April 20, 2011, the Colorado State District Court confirmed the arbitration award as a court judgment. WBI Energy Midstream filed an appeal from the Colorado State District Court's order and judgment to the Colorado Court of Appeals. The Colorado Court of Appeals issued a decision on May 24, 2012, reversing the Colorado State District Court order compelling arbitration, vacating the final award and remanding the case to the Colorado State District Court to determine SourceGas's claims and WBI Energy Midstream's counterclaims. As a result of the Colorado Court of Appeals decision, in the second quarter of 2012, WBI Energy Midstream changed its estimated loss related to this matter. This resulted in a reduction of expense of $24.1 million ($15.0 million after tax). On August 2, 2012, SourceGas filed a petition for writ of certiorari with the Colorado Supreme Court for review of the Colorado Court of Appeals decision which was denied on July 22, 2013. WBI Energy Midstream anticipates that on remand of the matter to the Colorado State District Court, SourceGas will assert claims similar to those asserted in the arbitration proceeding.

In a related matter, Omimex filed a complaint against WBI Energy Midstream in Montana Seventeenth Judicial District Court in July 2010 alleging WBI Energy Midstream breached a separate gathering contract with Omimex as a result of the increased operating pressures demanded by SourceGas on the same natural gas gathering system. In December 2011, Omimex filed an amended complaint alleging WBI Energy Midstream breached obligations to operate its gathering system as a common carrier under United States and Montana law. WBI Energy Midstream removed the action to the United States District Court for the District of Montana. Expert reports submitted by Omimex contended its damages as a result of the increased operating pressures were $16.1 million to $22.6 million, however, the experts revised their calculation of Omimex's damages to $1.0 million. The parties subsequently settled the breach of contract claim and, subject to a final determination on liability, stipulated to the damages on the common carrier claim, for amounts that are not material. A trial on the common carrier claim was held during July 2013.

The Company also is involved in other legal actions in the ordinary course of its business. After taking into account liabilities accrued for the foregoing matters, management believes that the outcomes with respect to the above and other legal proceedings will not have a material effect upon the Company's financial position, results of operations or cash flows.

Environmental matters

Portland Harbor Site In December 2000, Knife River - Northwest was named by the EPA as a PRP in connection with the cleanup of a riverbed site adjacent to a commercial property site acquired by Knife River - Northwest from Georgia-Pacific West, Inc. in 1999. The riverbed site is part of the Portland, Oregon, Harbor Superfund Site. The EPA wants responsible parties to share in the cleanup of sediment contamination in the Willamette River. To date, costs of the overall remedial investigation and feasibility study of the harbor site are being recorded, and initially paid, through an administrative consent order by the LWG, a group of several entities, which does not include Knife River - Northwest or Georgia-Pacific West, Inc. Investigative costs are indicated to be in excess of $70 million. It is not possible to estimate the cost of a corrective action plan until the remedial investigation and feasibility study have been completed, the EPA has decided on a strategy and a ROD has been published. Corrective action will be taken after the development of a proposed plan and ROD on the harbor site is issued. Knife River - Northwest also received notice in January 2008 that the Portland Harbor Natural Resource Trustee Council intends to

26

perform an injury assessment to natural resources resulting from the release of hazardous substances at the Harbor Superfund Site. The Portland Harbor Natural Resource Trustee Council indicates the injury determination is appropriate to facilitate early settlement of damages and restoration for natural resource injuries. It is not possible to estimate the costs of natural resource damages until an assessment is completed and allocations are undertaken.

Based upon a review of the Portland Harbor sediment contamination evaluation by the Oregon DEQ and other information available, Knife River - Northwest does not believe it is a Responsible Party. In addition, Knife River - Northwest has notified Georgia-Pacific West, Inc., that it intends to seek indemnity for liabilities incurred in relation to the above matters pursuant to the terms of their sale agreement. Knife River - Northwest has entered into an agreement tolling the statute of limitations in connection with the LWG's potential claim for contribution to the costs of the remedial investigation and feasibility study. By letter in March 2009, LWG stated its intent to file suit against Knife River - Northwest and others to recover LWG's investigation costs to the extent Knife River - Northwest cannot demonstrate its non-liability for the contamination or is unwilling to participate in an alternative dispute resolution process that has been established to address the matter. At this time, Knife River - Northwest has agreed to participate in the alternative dispute resolution process.

The Company believes it is not probable that it will incur any material environmental remediation costs or damages in relation to the above referenced administrative action.

Manufactured Gas Plant Sites There are three claims against Cascade for cleanup of environmental contamination at manufactured gas plant sites operated by Cascade's predecessors.

The first claim is for contamination at a site in Eugene, Oregon which was received in 1995. There are PRPs in addition to Cascade that may be liable for cleanup of the contamination. Some of these PRPs have shared in the investigation costs. It is expected that these and other PRPs will share in the cleanup costs. Several alternatives for cleanup have been identified, with preliminary cost estimates ranging from approximately $500,000 to $11.0 million. The Oregon DEQ is preparing a staff report which will recommend a cleanup alternative for the site. It is not known at this time what share of the cleanup costs will actually be borne by Cascade; however, Cascade anticipates its proportional share could be approximately 50 percent. Cascade has accrued $1.3 million for remediation of this site. In January 2013, the OPUC approved Cascade's application to defer environmental remediation costs at the Eugene site for a period of 12 months starting November 30, 2012.

The second claim is for contamination at a site in Bremerton, Washington which was received in 1997. A preliminary investigation has found soil and groundwater at the site contain contaminants requiring further investigation and cleanup. EPA conducted a Targeted Brownfields Assessment of the site and released a report summarizing the results of that assessment in August 2009. The assessment confirms that contaminants have affected soil and groundwater at the site, as well as sediments in the adjacent Port Washington Narrows. Alternative remediation options have been identified with preliminary cost estimates ranging from $340,000 to $6.4 million. Data developed through the assessment and previous investigations indicates the contamination likely derived from multiple, different sources and multiple current and former owners of properties and businesses in the vicinity of the site may be responsible for the contamination. In April 2010, the Washington Department of Ecology issued notice it considered Cascade a PRP for hazardous substances at the site. In May 2012, the EPA added the site to the National Priorities List. Cascade has entered into an administrative settlement agreement and consent order with the EPA regarding the scope and schedule for a remedial investigation and feasibility study for the site. Cascade has accrued $12.6 million for the remedial investigation, feasibility study and remediation of this site. In April 2010, Cascade filed a petition with the WUTC for authority to defer the costs, which are included in other noncurrent assets, incurred in relation to the environmental remediation of this site until the next general rate case. The WUTC approved the petition in September 2010, subject to conditions set forth in the order.

The third claim is for contamination at a site in Bellingham, Washington. Cascade received notice from a party in May 2008 that Cascade may be a PRP, along with other parties, for contamination from a manufactured gas plant owned by Cascade and its predecessor from about 1946 to 1962. The notice indicates that current estimates to complete investigation and cleanup of the site exceed $8.0 million. Other PRPs have reached an agreed order and work plan with the Washington Department of Ecology for completion of a remedial investigation and feasibility study for the site. A report documenting the initial phase of the remedial investigation was completed in June 2011. There is currently not enough information available to estimate the potential liability to Cascade associated with this claim although Cascade believes its proportional share of any liability will be relatively small in comparison to other PRPs. The plant manufactured gas from coal between approximately 1890 and 1946. In 1946, shortly after Cascade's predecessor acquired the plant, it converted the plant to a propane-air gas facility. There are no documented wastes or by-products resulting from the mixing or distribution of propane-air gas.

Cascade has received notices from certain of its insurance carriers that they will participate in defense of Cascade for these contamination claims subject to full and complete reservations of rights and defenses to insurance coverage. To the extent these

27

claims are not covered by insurance, Cascade will seek recovery through the OPUC and WUTC of remediation costs in its natural gas rates charged to customers. The accruals related to these matters are reflected in regulatory assets.

Guarantees

Centennial guaranteed CEM's obligations under a construction contract. For more information, see Litigation in this note.

In connection with the sale of the Brazilian Transmission Lines, as discussed in Note 11, Centennial has agreed to guarantee payment of any indemnity obligations of certain of the Company's indirect wholly owned subsidiaries who are the sellers in three purchase and sale agreements for periods ranging up to 10 years from the date of sale. The guarantees were required by the buyers as a condition to the sale of the Brazilian Transmission Lines.

WBI Holdings has guaranteed certain of Fidelity's oil and natural gas swap and collar agreement obligations. There is no fixed maximum amount guaranteed in relation to the oil and natural gas swap and collar agreements as the amount of the obligation is dependent upon oil and natural gas commodity prices. The amount of hedging activity entered into by the subsidiary is limited by corporate policy. The guarantees of the oil and natural gas swap and collar agreements at June 30, 2013, expire in the years ranging from 2013 to 2015; however, Fidelity continues to enter into additional hedging activities and, as a result, WBI Holdings from time to time may issue additional guarantees on these hedging obligations. The amount outstanding by Fidelity was $600,000 and was reflected on the Consolidated Balance Sheet at June 30, 2013. In the event Fidelity defaults under its obligations, WBI Holdings would be required to make payments under its guarantees.

Certain subsidiaries of the Company have outstanding guarantees to third parties that guarantee the performance of other subsidiaries of the Company. These guarantees are related to construction contracts, natural gas transportation and sales agreements, gathering contracts and certain other guarantees. At June 30, 2013, the fixed maximum amounts guaranteed under these agreements aggregated $69.2 million. The amounts of scheduled expiration of the maximum amounts guaranteed under these agreements aggregate $12.5 million in 2013; $36.6 million in 2014; $300,000 in 2015; $100,000 in 2016; $600,000 in 2018; $300,000 in 2019; $13.5 million, which is subject to expiration on a specified number of days after the receipt of written notice; and $5.3 million, which has no scheduled maturity date. The amount outstanding by subsidiaries of the Company under the above guarantees was $200,000 and was reflected on the Consolidated Balance Sheet at June 30, 2013. In the event of default under these guarantee obligations, the subsidiary issuing the guarantee for that particular obligation would be required to make payments under its guarantee.

Certain subsidiaries have outstanding letters of credit to third parties related to insurance policies and other agreements, some of which are guaranteed by other subsidiaries of the Company. At June 30, 2013, the fixed maximum amounts guaranteed under these letters of credit, aggregated $34.7 million. In 2013 and 2014, $5.7 million and $29.0 million, respectively, of letters of credit are scheduled to expire. There were no amounts outstanding under the above letters of credit at June 30, 2013.

WBI Holdings has an outstanding guarantee to WBI Energy Transmission. This guarantee is related to a natural gas transportation and storage agreement that guarantees the performance of Prairielands. At June 30, 2013, the fixed maximum amount guaranteed under this agreement was $5.0 million and is scheduled to expire in 2014. In the event of Prairielands' default in its payment obligations, WBI Holdings would be required to make payment under its guarantee. The amount outstanding by Prairielands under the above guarantee was $900,000. The amount outstanding under this guarantee was not reflected on the Consolidated Balance Sheet at June 30, 2013, because this intercompany transaction was eliminated in consolidation.

In addition, Centennial, Knife River and MDU Construction Services have issued guarantees to third parties related to the routine purchase of maintenance items, materials and lease obligations for which no fixed maximum amounts have been specified. These guarantees have no scheduled maturity date. In the event a subsidiary of the Company defaults under these obligations, Centennial, Knife River and MDU Construction Services would be required to make payments under these guarantees. Any amounts outstanding by subsidiaries of the Company for these guarantees were reflected on the Consolidated Balance Sheet at June 30, 2013.

In the normal course of business, Centennial has surety bonds related to construction contracts and reclamation obligations of its subsidiaries, as well as an arbitration award. In the event a subsidiary of Centennial does not fulfill a bonded obligation, Centennial would be responsible to the surety bond company for completion of the bonded contract or obligation. A large portion of the surety bonds is expected to expire within the next 12 months; however, Centennial will likely continue to enter into surety bonds for its subsidiaries in the future. As of June 30, 2013, approximately $713 million of surety bonds were outstanding, which were not reflected on the Consolidated Balance Sheet.

28

Variable interest entities

The Company evaluates its arrangements and contracts with other entities to determine if they are VIEs and if so, if the Company is the primary beneficiary. GAAP provides a framework for identifying VIEs and determining when a company should include the assets, liabilities, noncontrolling interest, and results of activities of a VIE in its consolidated financial statements.

A VIE should be consolidated if a party with an ownership, contractual, or other financial interest in the VIE (a variable interest holder) has the power to direct the VIE's most significant activities and the obligation to absorb losses or right to receive benefits of the VIE that could be significant to the VIE. A variable interest holder that consolidates the VIE is called the primary beneficiary. Upon consolidation, the primary beneficiary generally must initially record all of the VIE's assets, liabilities, and noncontrolling interests at fair value and subsequently account for the VIE as if it were consolidated.

The Company's evaluation of whether it qualifies as the primary beneficiary of a VIE is highly complex and involves significant judgments, estimates and assumptions and includes a qualitative analysis of the activities that most significantly impact the VIE's economic performance and whether the Company has the power to direct those activities, the design of the entity, the rights of the parties, and the purpose of the arrangement.

Dakota Prairie Refining, LLCOn February 7, 2013, WBI Energy and Calumet formed a limited liability company, Dakota Prairie Refining, and entered into an operating agreement to develop, build and operate a diesel topping plant in southwestern North Dakota. WBI Energy and Calumet each have a fifty percent ownership interest in Dakota Prairie Refining. WBI Energy's and Calumet's capital commitments under the agreement are $150 million and $75 million, respectively. Dakota Prairie Refining entered into a term loan for project debt financing of $75 million on April 22, 2013. The agreement provides for allocation of profits and losses consistent with ownership interests; however, deductions attributable to project financing debt will be allocated to Calumet. Calumet's future cash distributions from Dakota Prairie Refining will be decreased by the principal and interest to be paid on the project debt, while the cash distributions to WBI Energy will not be decreased. Pursuant to the agreement, Centennial agreed to guarantee Dakota Prairie Refining's obligation under the term loan.

Dakota Prairie Refining has been determined to be a VIE, and the Company has determined that it is the primary beneficiary as it has an obligation to absorb losses that could be potentially significant to the VIE through WBI Energy's equity investment and Centennial's guarantee of the third-party term loan. Accordingly, the Company consolidates Dakota Prairie Refining in its financial statements and records a noncontrolling interest for Calumet's ownership interest.

Construction on the diesel topping plant began in early 2013 and the plant is not yet operational. Therefore, the results of operations of Dakota Prairie Refining did not have a material effect on the Company's Consolidated Statements of Income. The assets of Dakota Prairie Refining shall be used solely for the benefit of Dakota Prairie Refining. The total assets and liabilities of Dakota Prairie Refining reflected on the Company's Consolidated Balance Sheets were as follows:

	June 30, 2013
	(In thousands)
ASSETS
Current assets:
Cash and cash equivalents	$	63,089
Accounts receivable	5
Total current assets	63,094
Net property, plant and equipment	75,216
Total assets	$	138,310
LIABILITIES
Current liabilities:
Accounts payable	$	21,057
Long-term debt due within one year	3,000
Other accrued liabilities	300
Total current liabilities	24,357
Long-term debt	72,000
Total liabilities	$	96,357

Fuel Contract On October 10, 2012, the Coyote Station entered into a new coal supply agreement with Coyote Creek which will replace a coal supply agreement expiring in May 2016. The new agreement provides for the purchase of coal necessary to

29

supply the coal requirements of the Coyote Station, of which the Company is a 25.0 percent owner, for the period May 2016 through December 2040.

The new coal supply agreement creates a variable interest in Coyote Creek due to the transfer of all operating and economic risk to the Coyote Station owners as the agreement is structured so the price of the coal will cover all costs of operations as well as future reclamation costs. The Coyote Station owners are also providing a guarantee of the value of the assets of Coyote Creek as they would be required to buy the assets at book value should they terminate the contract prior to the end of the contract term and are providing a guarantee of the value of the equity of Coyote Creek in that they are required to buy the entity at the end of the contract term at equity value. Although the Company has determined that Coyote Creek is a VIE, the Company has concluded that it is not the primary beneficiary of Coyote Creek because the authority to direct the activities of the entity is shared by the four unrelated owners of the Coyote Station with no primary beneficiary existing. As a result, Coyote Creek is not required to be consolidated in the Company's financial statements.

At June 30, 2013, Coyote Creek was not yet operational. The assets and liabilities of Coyote Creek and exposure to loss as a result of the Company's involvement with the VIE, based on the Company's ownership percentage, at June 30, 2013, was $7.1 million.

Note 20 - Subsequent events

On July 9, 2013, Cascade entered into a $50 million revolving credit agreement which replaces the existing revolving credit agreement and extends the termination date to July 9, 2018.

On July 15, 2013, Intermountain entered into a $65 million revolving credit agreement which replaces the existing revolving credit agreement and extends the termination date to July 13, 2018.

30

ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIALCONDITION AND RESULTS OF OPERATIONS

OVERVIEW

The Company's strategy is to apply its expertise in energy and transportation infrastructure industries to increase market share, increase profitability and enhance shareholder value through:

• Organic growth as well as a continued disciplined approach to the acquisition of well-managed companies and properties

• The elimination of system-wide cost redundancies through increased focus on integration of operations and standardization and consolidation of various support services and functions across companies within the organization

• The development of projects that are accretive to earnings per share and return on invested capital

The Company has capabilities to fund its growth and operations through various sources, including internally generated funds, commercial paper facilities, revolving credit facilities and the issuance from time to time of debt and equity securities. For more information on the Company's net capital expenditures, see Liquidity and Capital Commitments.

The key strategies for each of the Company's business segments and certain related business challenges are summarized below. For a summary of the Company's business segments, see Note 16.

Key Strategies and Challenges

Electric and Natural Gas Distribution

Strategy Provide competitively priced energy and related services to customers. The electric and natural gas distribution segments continually seek opportunities to retain, grow and expand their customer base through extensions of existing operations, including building and upgrading electric generation and transmission and natural gas systems, and through selected acquisitions of companies and properties at prices that will provide stable cash flows and an opportunity for the Company to earn a competitive return on investment.

Challenges Both segments are subject to extensive regulation in the state jurisdictions where they conduct operations with respect to costs and permitted returns on investment as well as subject to certain operational, system integrity and environmental regulations. These regulations can require substantial investment to upgrade facilities. The ability of these segments to grow through acquisitions is subject to significant competition. In addition, the ability of both segments to grow service territory and customer base is affected by the economic environment of the markets served and competition from other energy providers and fuels. The construction of any new electric generating facilities, transmission lines and other service facilities are subject to increasing cost and lead time, extensive permitting procedures, and federal and state legislative and regulatory initiatives, which will necessitate increases in electric energy prices. Legislative and regulatory initiatives to increase renewable energy resources and reduce GHG emissions could impact the price and demand for electricity and natural gas.

Pipeline and Energy Services

Strategy Utilize the segment's existing expertise in energy infrastructure and related services to increase market share and profitability through optimization of existing operations, internal growth, and acquisitions of energy-related assets and companies. Incremental and new growth opportunities include: access to new energy sources for storage, gathering and transportation services; expansion of existing gathering, transmission and storage facilities; incremental expansion of pipeline capacity; expansion of midstream business to include liquid pipelines and processing/refining activities; and expansion of related energy services.

Challenges Challenges for this segment include: energy price volatility; natural gas basis differentials; environmental and regulatory requirements; recruitment and retention of a skilled workforce; and competition from other pipeline and energy services companies.

Exploration and Production

Strategy Apply technology and utilize existing exploration and production expertise, with a focus on operated properties, to increase production and reserves from existing leaseholds, and to seek additional reserves and production opportunities both in new and existing areas to further expand the segment's asset base. By optimizing existing operations and taking advantage of new and incremental growth opportunities, this segment is focused on balancing the oil and natural gas commodity mix to maximize profitability with its goal to add value by increasing both reserves and production over the long term so as to generate competitive returns on investment.

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Challenges Volatility in natural gas and oil prices; timely receipt of necessary permits and approvals; environmental and regulatory requirements; recruitment and retention of a skilled workforce; availability of drilling rigs, materials, auxiliary equipment and industry-related field services; inflationary pressure on development and operating costs; and competition from other exploration and production companies are ongoing challenges for this segment.

Construction Materials and Contracting

Strategy Focus on high-growth strategic markets located near major transportation corridors and desirable mid-sized metropolitan areas; strengthen long-term, strategic aggregate reserve position through purchase and/or lease opportunities; enhance profitability through cost containment, margin discipline and vertical integration of the segment's operations; develop and recruit talented employees; and continue growth through organic and acquisition opportunities. Vertical integration allows the segment to manage operations from aggregate mining to final lay-down of concrete and asphalt, with control of and access to permitted aggregate reserves being significant. A key element of the Company's long-term strategy for this business is to further expand its market presence in the higher-margin materials business (rock, sand, gravel, liquid asphalt, asphalt concrete, ready-mixed concrete and related products), complementing and expanding on the Company's expertise.

Challenges Recruitment and retention of key personnel and volatility in the cost of raw materials such as diesel, gasoline, liquid asphalt, cement and steel, continue to be a concern. This business unit expects to continue cost containment efforts, positioning its operations for the resurgence in the private market, while continuing the emphasis on industrial, energy and public works projects.

Construction Services

Strategy Provide a superior return on investment by: building new and strengthening existing customer relationships; effectively controlling costs; retaining, developing and recruiting talented employees; and focusing our efforts on projects that will permit higher margins while properly managing risk.

Challenges This segment operates in highly competitive markets with many jobs subject to competitive bidding. Maintenance of effective operational and cost controls, retention of key personnel, managing through downturns in the economy and effective management of working capital are ongoing challenges.

For more information on the risks and challenges the Company faces as it pursues its growth strategies and other factors that should be considered for a better understanding of the Company's financial condition, see Item 1A - Risk Factors, as well as Part I, Item 1A - Risk Factors in the 2012 Annual Report. For more information on each segment's key growth strategies, projections and certain assumptions, see Prospective Information. For information pertinent to various commitments and contingencies, see Notes to Consolidated Financial Statements.

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Earnings Overview

The following table summarizes the contribution to consolidated earnings by each of the Company's businesses.

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2013			2012			2013			2012
	(Dollars in millions, where applicable)
Electric	$	4.4		$	4.4		$	14.2		$	12.0
Natural gas distribution	(5.9		)	(6.4		)	26.6			19.1
Pipeline and energy services	(6.4		)	15.8			(4.1		)	18.6
Exploration and production	33.0			18.0			53.3			30.9
Construction materials and contracting	10.0			7.8			(10.5		)	(17.1		)
Construction services	12.9			8.7			24.6			20.1
Other	.5			.5			0.9			1.0
Intersegment eliminations	(2.1		)	—			(2.1		)	—
Earnings before discontinued operations	46.4			48.8			102.9			84.6
Income (loss) from discontinued operations, net of tax	(.1		)	5.1			(.2		)	5.0
Earnings on common stock	$	46.3		$	53.9		$	102.7		$	89.6
Earnings per common share - basic:
Earnings before discontinued operations	$	.25		$	.26		$	.54		$	.45
Discontinued operations, net of tax	—			.03			—			.02
Earnings per common share - basic	$	.25		$	.29		$	.54		$	.47
Earnings per common share - diluted:
Earnings before discontinued operations	$	.24		$	.26		$	.54		$	.45
Discontinued operations, net of tax	—			.03			—			.02
Earnings per common share - diluted	$	.24		$	.29		$	.54		$	.47

Three Months Ended June 30, 2013 and 2012 Consolidated earnings for the quarter ended June 30, 2013, decreased $7.6 million (14 percent) from the comparable prior period largely due to:

• Absence of a 2012 net benefit related to the natural gas gathering operations litigation of $15.0 million (after tax), as discussed in Note 19, as well as an impairment of coalbed natural gas gathering assets of $9.0 million (after tax) in 2013 compared to an impairment of $1.7 million (after tax) in 2012, at the pipeline and energy services business

• Loss from discontinued operations of $100,000 (after tax) compared to income from discontinued operations of $5.1 million (after tax) in 2012, as discussed in Note 10

Partially offsetting these decreases were:

• Increased oil production, higher average realized natural gas prices, as well as a higher unrealized gain on commodity derivatives of $8.2 million (after tax) compared to $3.0 million (after tax) in 2012, partially offset by higher depreciation, depletion and amortization expense and a lower realized gain on commodity derivatives at the exploration and production business

• Higher workloads and margins and higher equipment sales and rental margins, partially offset by higher general and administrative expense at the construction services business

Six Months Ended June 30, 2013 and 2012 Consolidated earnings for the six months ended June 30, 2013, increased $13.1 million (15 percent) from the comparable prior period largely due to:

• Increased oil production, higher average realized natural gas prices, as well as a higher unrealized gain on commodity derivatives of $4.6 million (after tax) compared to $500,000 (after tax) in 2012, partially offset by higher depreciation, depletion and amortization expense, decreased natural gas production, a lower realized gain on commodity derivatives, higher production taxes, as well as increased lease operating expenses at the exploration and production business

• Increased retail sales volumes and a gain on the sale of a nonregulated appliance service and repair business at the natural gas distribution business

• Higher asphalt, liquid asphalt oil, construction and ready-mixed concrete margins, partially offset by lower other product line margins at the construction materials and contracting business

33

Partially offsetting these increases was the absence of the 2012 net benefit of $15.0 million (after tax), as previously discussed, and the impairment of coalbed natural gas gathering assets of $9.0 million (after tax) in 2013, compared to an impairment of $1.7 million in 2012, at the pipeline and energy services business.

FINANCIAL AND OPERATING DATA

Below are key financial and operating data for each of the Company's businesses.

Electric

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013		2012
	(Dollars in millions, where applicable)
Operating revenues	$	57.0	$	53.0	$	121.6	$	110.9
Operating expenses:
Fuel and purchased power	18.2		15.2		39.8		33.6
Operation and maintenance	20.5		19.1		36.8		35.3
Depreciation, depletion and amortization	7.9		8.0		16.5		16.1
Taxes, other than income	2.8		2.6		5.7		5.3
	49.4		44.9		98.8		90.3
Operating income	7.6		8.1		22.8		20.6
Earnings	$	4.4	$	4.4	$	14.2	$	12.0
Retail sales (million kWh)	691.5		666.3		1,534.1		1,436.0
Sales for resale (million kWh)	8.8		1.0		16.2		2.9
Average cost of fuel and purchased power per kWh	$	.024	$	.021	$	.024	$	.022

Three Months Ended June 30, 2013 and 2012 Electric earnings decreased $9,000 due to:

• Higher operation and maintenance expense of $700,000 (after tax), including increased contract services at certain of the Company's electric generation stations and higher payroll-related costs, offset in part by lower benefit-related costs

• Increased taxes other than income of $200,000 (after tax), primarily related to higher property taxes

Largely offsetting these decreases were increased retail sales volumes of 4 percent, primarily to residential customers due to increased customer growth.

Six Months Ended June 30, 2013 and 2012 Electric earnings increased $2.2 million (19 percent) due to:

• Increased retail sales volumes of 7 percent, primarily to residential and small commercial and industrial customers due to increased customer growth, as well as weather variances from last year

• Higher other income, largely allowance for funds used during construction of $500,000

Partially offsetting these increases was higher operation and maintenance expense, which includes $600,000 (after tax) of expenses largely related to higher payroll-related costs, increased contract services, as well as higher material costs, offset in part by lower benefit-related costs.

34

Natural Gas Distribution

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2013			2012			2013			2012
	(Dollars in millions, where applicable)
Operating revenues	$	127.6		$	116.8		$	459.3		$	424.7
Operating expenses:
Purchased natural gas sold	73.5			62.9			286.9			262.2
Operation and maintenance	35.7			35.9			69.9			71.1
Depreciation, depletion and amortization	12.4			11.3			24.5			22.5
Taxes, other than income	9.5			10.0			25.7			26.2
	131.1			120.1			407.0			382.0
Operating income (loss)	(3.5		)	(3.3		)	52.3			42.7
Earnings (loss)	$	(5.9	)	$	(6.4	)	$	26.6		$	19.1
Volumes (MMdk):
Sales	15.3			13.4			60.2			52.1
Transportation	30.3			26.8			68.5			64.7
Total throughput	45.6			40.2			128.7			116.8
Degree days (% of normal)*
Montana-Dakota/Great Plains	130		%	77		%	104		%	77		%
Cascade	82		%	94		%	93		%	99		%
Intermountain	99		%	97		%	110		%	94		%
Average cost of natural gas, including transportation, per dk	$	4.82		$	4.70		$	4.77		$	5.03
* Degree days are a measure of the daily temperature-related demand for energy for heating.

Three Months Ended June 30, 2013 and 2012 The natural gas distribution business recognized a seasonal loss of $5.9 million compared to a seasonal loss of $6.4 million a year ago. The improvement was the result of:

• Increased retail sales volumes of 14 percent, largely resulting from colder weather than last year, partially offset by weather normalization adjustments in certain jurisdictions

• Lower net interest expense of $700,000 (after tax), primarily due to lower average interest rates

Partially offsetting these items were:

• Increased depreciation, depletion and amortization expense of $700,000 (after tax), primarily resulting from higher property, plant and equipment balances

• Lower other income of $400,000 (after tax), largely lower allowance for funds used during construction

Six Months Ended June 30, 2013 and 2012 Earnings at the natural gas distribution business increased $7.5 million (39 percent) due to:

• Increased retail sales volumes of 16 percent, largely resulting from colder weather than last year, partially offset by weather normalization adjustments in certain jurisdictions

• A $2.8 million (after tax) gain on the sale of Montana-Dakota's nonregulated appliance service and repair business

• Lower net interest expense of $1.2 million (after tax), as previously discussed

Partially offsetting these increases was increased depreciation, depletion and amortization expense of $1.2 million (after tax), as previously discussed.

35

Pipeline and Energy Services

	Three Months Ended								Six Months Ended
	June 30,								June 30,
	2013				2012				2013				2012
	(Dollars in millions)
Operating revenues	$	50.9			$	43.6			$	97.3			$	93.2
Operating expenses:
Purchased natural gas sold	15.8				8.5				28.6				24.6
Operation and maintenance	32.1			*	(1.4		)	**	49.3			*	15.6		**
Depreciation, depletion and amortization	7.7				6.8				14.9				13.1
Taxes, other than income	3.5				3.5				6.9				6.9
	59.1				17.4				99.7				60.2
Operating income (loss)	(8.2		)		26.2				(2.4		)		33.0
Earnings (loss)	$	(6.4	)	*	$	15.8		**	$	(4.1	)	*	$	18.6	**
Transportation volumes (MMdk)	40.3				36.8				77.1				68.8
Natural gas gathering volumes (MMdk)	10.0				11.6				19.9				25.8
Customer natural gas storage balance (MMdk):
Beginning of period	24.7				27.3				43.7				36.0
Net injection (withdrawal)	.5				13.1				(18.5		)		4.4
End of period	25.2				40.4				25.2				40.4
* Reflects an impairment of coalbed natural gas gathering assets of $14.5 million ($9.0 million after tax). ** Reflects a net benefit of $24.1 million ($15.0 million after tax) related to the natural gas gathering operations litigation, largely reflected in operation and maintenance expense, as discussed in Note 19, as well as an impairment of coalbed natural gas gathering assets of $2.7 million ($1.7 million after tax).

Three Months Ended June 30, 2013 and 2012 The pipeline and energy services business recognized a loss of $6.4 million compared to earnings of $15.8 million for the comparable prior period due to:

• Absence of the 2012 net benefit of $15.0 million (after tax) related to the natural gas gathering operations litigation, as discussed in Note 19

• An impairment of coalbed natural gas gathering assets of $9.0 million (after tax) in 2013, compared to an impairment of $1.7 million (after tax) in 2012, largely resulting from low natural gas prices, as discussed in Note 5

• Lower storage services revenue of $1.0 million (after tax), largely due to lower average rates and lower average storage balances

These decreases were partially offset by lower operation and maintenance expense (excluding the asset impairments and net benefit related to the natural gas gathering operations litigation), as well as higher revenue associated with the Company's May 2012 acquisition of oil and natural gas gathering and processing assets.

Results also reflect higher operating revenues and higher purchased natural gas sold, both related to higher natural gas prices.

Six Months Ended June 30, 2013 and 2012 The pipeline and energy services business recognized a loss of $4.1 million compared to earnings of $18.6 million for the the comparable prior period largely due to:

• Absence of the 2012 net benefit of $15.0 million (after tax), as previously discussed

• An impairment of coalbed natural gas gathering assets of $9.0 million (after tax) in 2013, compared to an impairment of $1.7 million (after tax) in 2012, as previously discussed

• Lower earnings of $2.2 million (after tax) resulting from lower natural gas gathering volumes from existing operations, largely resulting from customers experiencing production curtailments, normal declines and deferral of natural gas development activity

• Lower storage services revenue of $900,000 (after tax), largely due to lower average rates

These decreases were partially offset by higher revenue associated with the Company's May 2012 acquisition of oil and natural gas gathering assets, as well as lower operation and maintenance expense, as previously discussed.

Results also reflect higher operating revenues and higher purchased natural gas sold, both related to higher natural gas prices.

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Exploration and Production

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013		2012
	(Dollars in millions, where applicable)
Operating revenues:
Oil	$	105.9	$	70.9	$	205.9	$	142.2
NGL	6.2		7.1		13.7		16.8
Natural gas	23.2		12.0		42.4		31.5
Realized gain on commodity derivatives	1.3		11.1		5.6		14.6
Unrealized gain on commodity derivatives	13.0		4.8		7.2		.7
	149.6		105.9		274.8		205.8
Operating expenses:
Operation and maintenance:
Lease operating costs	22.0		19.0		42.8		37.5
Gathering and transportation	4.2		4.2		8.5		8.5
Other	10.3		9.5		20.4		18.7
Depreciation, depletion and amortization	45.1		34.4		88.3		71.2
Taxes, other than income:
Production and property taxes	12.3		8.7		23.9		18.3
Other	.3		.3		.6		.6
	94.2		76.1		184.5		154.8
Operating income	55.4		29.8		90.3		51.0
Earnings	$	33.0	$	18.0	$	53.3	$	30.9
Production:
Oil (MBbls)	1,201		876		2,319		1,643
NGL (MBbls)	191		209		392		399
Natural gas (MMcf)	6,987		8,239		13,700		18,286
Total production (MBOE)	2,557		2,458		4,995		5,090
Average realized prices (excluding realized and unrealized gain on commodity derivatives):
Oil (per Bbl)	$	88.12	$	80.99	$	88.75	$	86.60
NGL (per Bbl)	$	32.26	$	33.77	$	34.86	$	41.91
Natural gas (per Mcf)	$	3.33	$	1.46	$	3.10	$	1.72
Average realized prices (including realized gain on commodity derivatives):
Oil (per Bbl)	$	90.55	$	83.06	$	91.18	$	85.73
NGL (per Bbl)	$	32.26	$	33.77	$	34.86	$	41.91
Natural gas (per Mcf)	$	3.09	$	2.59	$	3.09	$	2.60
Average depreciation, depletion and amortization rate, per BOE	$	16.90	$	13.32	$	16.90	$	13.32
Production costs, including taxes, per BOE:
Lease operating costs	$	8.59	$	7.74	$	8.57	$	7.37
Gathering and transportation	1.66		1.70		1.71		1.66
Production and property taxes	4.81		3.54		4.78		3.58
	$	15.06	$	12.98	$	15.06	$	12.61

Three Months Ended June 30, 2013 and 2012 Exploration and production earnings increased $15.0 million (84 percent) due to:

• Increased oil production of 37 percent, primarily related to drilling activity in the Bakken area, as well as the Paradox Basin

• Higher average realized natural gas prices of 128 percent, excluding gain on commodity derivatives

• Unrealized gain on commodity derivatives of $8.2 million (after tax) compared to $3.0 million (after tax) in 2012

• Higher average realized oil prices of 9 percent, excluding gain on commodity derivatives

37

Partially offsetting these increases were:

• Higher depreciation, depletion and amortization expense of $6.7 million (after tax), largely due to higher depletion rates

• Lower realized gain on commodity derivatives of $6.2 million (after tax), due to higher commodity prices

• Decreased natural gas production of 15 percent, largely related to production curtailments, normal declines and deferral of certain natural gas development activity

• Higher production taxes of $2.2 million (after tax), primarily resulting from higher revenues

• Increased lease operating expenses of $1.9 million (after tax), largely related to higher costs in the Bakken area resulting from increased production volumes and higher workover costs, as well as higher costs in the Paradox Basin resulting from increased production volumes, partially offset by lower costs at certain natural gas properties where curtailments of production have occurred

• Higher net interest expense of $1.2 million (after tax), primarily due to lower capitalized interest and higher average borrowings

Six Months Ended June 30, 2013 and 2012 Exploration and production earnings increased $22.4 million (72 percent) due to:

• Increased oil production of 41 percent, as previously discussed

• Higher average realized natural gas prices of 80 percent, excluding gain on commodity derivatives

• Unrealized gain on commodity derivatives of $4.6 million (after tax) compared to $500,000 (after tax) in 2012

• Higher average realized oil prices of 2 percent, excluding gain on commodity derivatives

Partially offsetting these increases were:

• Higher depreciation, depletion and amortization expense of $10.7 million (after tax), as previously discussed

• Decreased natural gas production of 25 percent, as previously discussed

• Lower realized gain on commodity derivatives of $5.7 million (after tax), as previously discussed

• Higher production taxes of $3.5 million (after tax), as previously discussed

• Increased lease operating expenses of $3.3 million (after tax), as previously discussed

• Higher net interest expense of $2.2 million (after tax), primarily due to lower capitalized interest and higher average borrowings, partially offset by lower effective interest rates

• Lower average realized NGL prices of 17 percent

• Higher general and administrative expense of $1.0 million (after tax), including higher payroll-related costs

Construction Materials and Contracting

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013			2012
	(Dollars in millions)
Operating revenues	$	431.3	$	442.1	$	597.6		$	591.5
Operating expenses:
Operation and maintenance	381.2		396.7		547.9			553.7
Depreciation, depletion and amortization	18.7		19.8		37.7			39.6
Taxes, other than income	10.6		10.6		19.1			18.6
	410.5		427.1		604.7			611.9
Operating income (loss)	20.8		15.0		(7.1		)	(20.4		)
Earnings (loss)	$	10.0	$	7.8	$	(10.5	)	$	(17.1	)
Sales (000's):
Aggregates (tons)	6,152		6,481		9,110			8,974
Asphalt (tons)	1,518		1,761		1,667			1,861
Ready-mixed concrete (cubic yards)	846		837		1,326			1,305

Three Months Ended June 30, 2013 and 2012 Earnings at the construction materials and contracting business increased $2.2 million (29 percent) due to:

• Higher earnings of $1.7 million (after tax) resulting from higher asphalt margins, primarily due to lower costs

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• Higher earnings of $1.6 million (after tax) resulting from higher liquid asphalt oil margins, primarily due to higher volumes and lower costs

• Higher earnings of $1.1 million (after tax) resulting from higher ready-mixed concrete margins, primarily due to lower costs

Partially offsetting these increases were:

• Lower earnings of $1.6 million (after tax), resulting from lower aggregate margins, primarily due to lower volumes and higher costs

• Higher interest expense of $500,000 (after tax), resulting from higher average interest rates, as well as higher average borrowings

Six Months Ended June 30, 2013 and 2012 Construction materials and contracting experienced a loss of $10.5 million, which was a 38 percent improvement, resulting from:

• Higher earnings of $2.9 million (after tax) resulting from higher asphalt margins, as previously discussed

• Higher earnings of $1.9 million (after tax) resulting from higher liquid asphalt oil margins, as previously discussed

• Increased construction margins of $1.6 million (after tax)

• Higher earnings of $1.5 million (after tax) resulting from higher ready-mixed concrete margins, as previously discussed

• Lower selling, general and administrative costs of $1.2 million (after tax)

Partially offsetting the decreased loss were:

• Lower earnings of $1.4 million (after tax) resulting from lower other product line margins, primarily due to higher costs

• Higher interest expense of $1.0 million (after tax), as previously discussed

Construction Services

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013		2012
	(In millions)
Operating revenues	$	279.6	$	224.1	$	511.0	$	442.3
Operating expenses:
Operation and maintenance	245.9		198.6		444.3		386.6
Depreciation, depletion and amortization	3.0		2.8		6.0		5.5
Taxes, other than income	8.4		7.2		18.0		15.0
	257.3		208.6		468.3		407.1
Operating income	22.3		15.5		42.7		35.2
Earnings	$	12.9	$	8.7	$	24.6	$	20.1

Three Months Ended June 30, 2013 and 2012 Construction services earnings increased $4.2 million (49 percent), primarily due to higher workloads and margins in all regions, as well as higher equipment sales and rental margins. These increases were partially offset by higher general and administrative expense of $1.1 million (after tax), including higher payroll-related costs.

Six Months Ended June 30, 2013 and 2012 Construction services earnings increased $4.5 million (22 percent), primarily due to higher workloads and margins in the Western region, as well as higher equipment sales and rental margins. These items were partially offset by higher general and administrative expense of $1.6 million (after tax), as well as lower margins in the Central region.

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Other

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2013			2012		2013			2012
	(In millions)
Operating revenues	$	2.3		$	2.5	$	4.5		$	4.6
Operating expenses:
Operation and maintenance	1.4			1.5		2.7			2.9
Depreciation, depletion and amortization	.5			.5		1.0			1.0
Taxes, other than income	—			.1		.1			—
	1.9			2.1		3.8			3.9
Operating income	.4			.4		.7			.7
Income from continuing operations	.5			.5		.9			1.0
Income (loss) from discontinued operations, net of tax	(.1		)	5.1		(.2		)	5.0
Earnings	$	.4		$	5.6	$	.7		$	6.0

Three Months Ended June 30, 2013 and 2012 Other earnings decreased $5.2 million, primarily due to a loss from discontinued operations of $100,000 (after tax) in 2013 compared to income from discontinued operations of $5.1 million (after tax) in 2012. This decrease is largely related to the absence of a net benefit in 2012, as discussed in Note 10.

Six Months Ended June 30, 2013 and 2012Other earnings decreased $5.3 million, primarily due to a loss from discontinued operations of $200,000 (after tax) in 2013 compared to income from discontinued operations of $5.0 million (after tax) in 2012, as previously discussed.

Intersegment Transactions

Amounts presented in the preceding tables will not agree with the Consolidated Statements of Income due to the Company's elimination of intersegment transactions. The amounts relating to these items are as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2013		2012		2013		2012
	(In millions)
Intersegment transactions:
Operating revenues	$	37.7	$	20.0	$	73.9	$	52.2
Purchased natural gas sold	19.1		13.0		46.1		42.9
Operation and maintenance	15.2		7.0		24.4		9.3
Income taxes	1.4		—		1.4		—
Earnings on common stock	2.1		—		2.1		—

For more information on intersegment eliminations, see Note 16.

PROSPECTIVE INFORMATION

The following information highlights the key growth strategies, projections and certain assumptions for the Company and its subsidiaries and other matters for certain of the Company's businesses. Many of these highlighted points are "forward-looking statements." There is no assurance that the Company's projections, including estimates for growth and changes in earnings, will in fact be achieved. Please refer to assumptions contained in this section, as well as the various important factors listed in Part II, Item 1A - Risk Factors, as well as Part I, Item 1A - Risk Factors in the 2012 Annual Report. Changes in such assumptions and factors could cause actual future results to differ materially from the Company's growth and earnings projections.

MDU Resources Group, Inc.

• Earnings per common share for 2013, diluted, are projected in the range of $1.30 to $1.40, excluding discontinued operations, the unrealized gain on commodity derivatives of $8.2 million (after tax) and the natural gas gathering asset impairment of $9.0 million (after tax). Including these adjustments, 2013 GAAP earnings guidance is in the same range. The unrealized commodity derivatives fair value is likely to fluctuate on a quarterly basis, which could cause the GAAP guidance range to change accordingly.

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• The Company's long-term compound annual growth goals on earnings per share from operations are in the range of 7 to 10 percent.

• The Company continually seeks opportunities to expand through organic growth and strategic acquisitions.

• The Company focuses on creating value through vertical integration between its business units. For example, the pipeline and energy services business' partially owned diesel topping plant under construction in the Bakken region will have the construction materials and services business involved in constructing the facility, the exploration and production business supplying production to the plant, the pipeline transporting natural gas to the plant, and the utility supplying electricity.

Electric and natural gas distribution

• The Company filed an application on June 14, 2013, for an advance determination of prudence with the NDPSC to add pollution control equipment at the Lewis & Clark generating station, as discussed in Note 18.

• The Company filed an application December 21, 2012, with the SDPUC for a natural gas rate increase, as discussed in Note 18.

• The Company filed an application September 26, 2012, with the MTPSC for a natural gas rate increase, as discussed in Note 18.

• The EPA approved the South Dakota Regional Haze Program, which requires the Big Stone Station to install and operate a BART air-quality control system to reduce emissions of particulate matter, sulfur dioxide and nitrogen oxides. The Company's share of the cost for the installation is estimated at $100 million and is expected to be complete in 2015. The NDPSC has approved advance determination of prudence for recovery of costs related to this system in electric rates charged to customers. The Company filed an application February 11, 2013, with the NDPSC for approval of an environmental cost recovery rider related to costs for the required environmental retrofit at the Big Stone Station, as discussed in Note 18.

• The Company plans to construct and operate an 88-MW simple-cycle natural gas turbine and associated facilities, with an estimated project cost of $86 million and a projected in-service date in third quarter 2014. It will be located on owned property that is adjacent to the Company's Heskett Generating Station near Mandan, North Dakota. The capacity is necessary to meet the requirements of the Company's integrated electric system customers and will be a partial replacement for third-party contract capacity expiring in 2015. Advance determination of prudence and a Certificate of Public Convenience and Necessity have been received from the NDPSC.

• Planned investments are approximately $75 million for 2013 to serve the growing electric and natural gas customer base associated with the Bakken oil development in western North Dakota and eastern Montana.

• Rate base growth is projected to be approximately 6 percent compounded annually over the next five years.

• The Company is analyzing potential projects for accommodating load growth in its industrial and agricultural sectors, with company- and customer-owned pipeline facilities designed to serve existing facilities served by fuel oil or propane, and to serve new customers. The Company is engaged in a 30-mile natural gas line project into the Hanford Nuclear Site in Washington.

• The Company is involved with a number of pipeline projects to enhance the reliability and deliverability of its system in the Pacific Northwest and Idaho.

• Opportunities associated with the potential development of high-voltage transmission lines and system enhancements targeted toward delivery of energy to major market areas are being pursued.

Pipeline and energy services

• The Company, in conjunction with Calumet, has formed Dakota Prairie Refining to develop, build and operate a 20,000 barrel-per-day diesel topping plant in southwestern North Dakota. Construction began on the facility in late March 2013 and when complete will process Bakken crude and market the diesel within the Bakken region. Total project costs are estimated to be approximately $300 million, with a projected in-service date in late 2014.

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• In May 2012, the Company purchased a 50 percent undivided interest in Whiting Oil and Gas Corporation's Pronghorn natural gas and oil midstream assets near Belfield, North Dakota, in the Bakken area. The Company invested approximately $100 million in 2012 including the purchase price. The Belfield natural gas processing plant has an inlet processing capacity of 35 MMcf per day. The Company will receive a full year of benefit from this acquisition in 2013.

• In August 2012, the Company placed in service approximately 13 miles of high-pressure transmission pipeline from the Stateline processing facilities in northwestern North Dakota to deliver natural gas into the Northern Border Pipeline, which is expected to result in increased transportation volumes for 2013.

• Dry natural gas gathering volumes are expected to be lower in 2013 compared to 2012 because of curtailments and the deferral of development activity by producers.

• The Company has an agreement to construct a pipeline in 2014 to connect the planned Garden Creek II gas processing plant in northwestern North Dakota to deliver natural gas into the Northern Border Pipeline.

• In May 2013, the Company announced plans for a proposed natural gas pipeline from far western North Dakota to western Minnesota to transport natural gas to markets in eastern North Dakota, Minnesota and Wisconsin. The pipeline would initially transport approximately 400 MMcf per day of natural gas and could be expanded to more than 500 MMcf per day. The project investment is estimated to be $650 million to $700 million. Long-term capacity commitments on the proposed pipeline will be sought during an open season expected to begin this fall. Following receipt of adequate capacity commitments and necessary permits and regulatory approvals, construction on the new pipeline would begin in early 2016 with completion expected by late 2016.

• The Company continues to pursue expansion of facilities and services offered to customers. Energy development within its geographic region, which includes portions of Colorado, Montana, North Dakota and Wyoming, is expanding, most notably the Bakken area of North Dakota and eastern Montana. The Company owns an extensive natural gas pipeline system in the Bakken area. Ongoing energy development is expected to have many direct and indirect benefits to this business.

Exploration and production

• The Company expects to spend approximately $400 million in capital expenditures in 2013. With improving well cost efficiencies and having essentially completed the extensive 2012 exploration program, the capital program will focus on growth projects where the Company expects higher returns, namely the Bakken, Paradox Basin and Texas, as described below. The 2013 planned capital expenditure total does not include potential acquisitions.

• For 2013, the Company expects a 25 to 35 percent increase in oil production, a flat to slight decrease in NGL production, and a 15 to 25 percent decrease in natural gas production. The majority of the capital program is focused on growing oil production considering current relative commodity prices. The Company expects to return to some natural gas development when the commodity prices make it more profitable to do so.

• The Company has a total of four drilling rigs deployed on its acreage in the Bakken, Paradox and Texas areas.

• Bakken areas

◦ The Company owns a total of approximately 127,000 net acres of leaseholds in Mountrail, Stark and Richland counties.

◦ Capital expenditures are expected to total approximately $200 million in 2013. During second quarter 2013, the Company operated three rigs in the play and as drilling efficiencies have accelerated, two rigs are now being utilized.

◦ Net oil production for second quarter 2013, was more than 7,500 BOPD.

◦ In mid-July 2013, the first three-well pad in Mountrail county began producing. In the first 10 days of production, the pad averaged 2,770 BOPD gross, 1,160 BOPD net. The potential exists for 10 additional multi-well pads in Mountrail county.

• Paradox Basin, Utah

◦ The Company has approximately 92,000 net acres and also has an option to lease another 20,000 acres.

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◦ Capital expenditures are expected to total $80 million in 2013. The Company expects to operate one rig throughout the year.

◦ Net oil production for second quarter 2013, was approximately 2,300 BOPD, up 44 percent from first quarter 2013.

◦ Following nine months of flowing at a constant 1,500 BOPD gross, the CCU 12-1 well recently came off its plateau rate and is still flowing at 1,100 BOPD. The well has flowed over 400 MBO on a cumulative basis and has a forecasted EUR of 1.2 to 1.4 MMBO. This well is amongst the best onshore oil wells drilled in the United States last year.

◦ The last three wells drilled are the CCU 18-1, CCU 13-1 and the CCU 17-1. The respective gross consistent flowing rates are 900 BOPD, 700 BOPD and 500 BOPD. Respective EURs are forecast at 500 to 700 MBO, 400 to 600 MBO and 400 to 600 MBO.

◦ The Company's understanding of this play and the quality of the play continues to improve. Accelerated development of the play will be largely dependent upon receiving sufficient permits to sustain a multi-rig program. It is anticipated that this field will play a key role in the Company's oil growth strategy.

• Texas

◦ The Company is targeting areas that have the potential for higher liquids content with approximately $35 million of capital planned for this year.

• Other opportunities

◦ Upon evaluation of wells drilled by the Company in Sioux County, Nebraska, the decision was made to decline an option to purchase acreage in the area at this time.

◦ The remaining forecasted 2013 capital has been allocated to other operated and non-operated opportunities.

• Earnings guidance reflects estimated average NYMEX index prices for August through December in the range of $90.00 to $100.00 per Bbl of crude oil, and $3.50 to $4.00 per Mcf of natural gas. Estimated prices for NGL are in the range of $30.00 to $45.00 per Bbl.

• For the last six months of 2013, the Company has derivative instruments for 11,000 BOPD utilizing swaps and costless collars with a weighted average price of $97.76 and $92.50/$107.03 (floor/ceiling) respectively, and 50,000 MMBtu of natural gas per day, with an additional 10,000 MMBtu per day for September through December, utilizing swaps at a weighted average price of $3.78. 

• For the first six months of 2014, the Company has derivative instruments for 8,000 BOPD, and 2,000 BOPD for July through December, utilizing swaps with a weighted average price of $93.43, and for 2014 the Company has derivative instruments for 20,000 MMBtu of natural gas per day utilizing swaps at a weighted average price of $4.13.

• For 2015, the Company has a derivative instrument for 10,000 MMBtu of natural gas per day utilizing a swap at $4.2825.

• The commodity derivative instruments that are in place as of July 31, 2013, are summarized in the following chart:

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Commodity	Type	Index	Period Outstanding	Forward Notional Volume (Bbl/MMBtu)	Price (Per Bbl/MMBtu)
Crude Oil	Collar	NYMEX	7/13 - 12/13	184,000	$95.00-$117.00
Crude Oil	Collar	NYMEX	7/13 - 12/13	184,000	$90.00-$97.05
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$95.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$95.30
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$100.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$100.02
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$102.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$104.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$98.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$94.15
Crude Oil	Swap	NYMEX	7/13 - 12/13	92,000	$94.00
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$97.45
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$94.15
Crude Oil	Swap	NYMEX	7/13 - 12/13	184,000	$95.00
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$95.15
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$95.00
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$90.00
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$91.00
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$92.00
Crude Oil	Swap	NYMEX	1/14 - 6/14	181,000	$93.00
Crude Oil	Swap	NYMEX	1/14 - 12/14	365,000	$94.05
Crude Oil	Swap	NYMEX	1/14 - 12/14	365,000	$95.00
Natural Gas	Swap	NYMEX	7/13 - 12/13	1,840,000	$3.76
Natural Gas	Swap	NYMEX	7/13 - 12/13	1,840,000	$3.90
Natural Gas	Swap	NYMEX	7/13 - 12/13	1,840,000	$4.00
Natural Gas	Swap	NYMEX	7/13 - 12/13	3,680,000	$3.50
Natural Gas	Swap	NYMEX	9/13 - 12/14	4,870,000	$4.13
Natural Gas	Swap	NYMEX	1/14 - 12/14	3,650,000	$4.13
Natural Gas	Swap	NYMEX	1/15 - 12/15	3,650,000	$4.2825

Construction materials and contracting

• Approximate work backlog as of June 30, 2013, was $730 million, compared to $636 million a year ago. Private work represents 13 percent of construction backlog, up from 8 percent a year ago. Public work represents 87 percent of backlog. The backlog includes a variety of projects such as highway paving projects, airports, bridge work, reclamation and harbor expansions.

• The Company's approximate backlog in North Dakota was $165 million, compared to $83 million a year ago.

• Projected revenues included in the Company's 2013 earnings guidance are in the range of $1.6 billion to $1.7 billion.

• The Company anticipates margins in 2013 to be higher than 2012.

• The Company continues to pursue opportunities for expansion in energy projects such as refineries, transmission, wind towers and geothermal. Initiatives are aimed at capturing additional market share and expanding into new markets.

• As the country's sixth-largest sand and gravel producer, the Company will continue to strategically manage its 1.1 billion tons of aggregate reserves in all its markets, as well as take further advantage of being vertically integrated.

44

• Of the four labor contracts that Knife River was negotiating, as reported in Items 1 and 2 - Business and Properties - General in the 2012 Annual Report, all have been ratified.

Construction services

• Approximate work backlog as of June 30, 2013, was $447 million, compared to $344 million a year ago. The backlog includes a variety of projects such as substation and line construction, solar and other commercial, institutional and industrial projects including refinery work.

• The Company has no backlog in North Dakota in 2013, compared to $3 million a year ago.

• Projected revenues included in the Company's 2013 earnings guidance are in the range of $1.0 billion to $1.1 billion.

• The Company anticipates higher workloads and comparable margins in 2013 compared to 2012.

• The Company continues to pursue opportunities for expansion in energy projects such as refineries, transmission, substations, utility services, as well as solar. Initiatives are aimed at capturing additional market share and expanding into new markets.

NEW ACCOUNTING STANDARDS

For information regarding new accounting standards, see Note 8, which is incorporated by reference.

CRITICAL ACCOUNTING POLICIES INVOLVING SIGNIFICANT ESTIMATES

The Company's critical accounting policies involving significant estimates include impairment testing of oil and natural gas properties, impairment testing of long-lived assets and intangibles, revenue recognition, pension and other postretirement benefits, and income taxes. There were no material changes in the Company's critical accounting policies involving significant estimates from those reported in the 2012 Annual Report. For more information on critical accounting policies involving significant estimates, see Part II, Item 7 in the 2012 Annual Report.

LIQUIDITY AND CAPITAL COMMITMENTS

At June 30, 2013, the Company had cash and cash equivalents of $115.0 million and available capacity of $207.8 million under the outstanding credit facilities of the Company and its subsidiaries. The Company expects to meet its obligations for debt maturing within one year from various sources, including internally generated funds; the Company's credit facilities, as described later; and through the issuance of long-term debt and the Company's equity securities.

Cash flows

Operating activitiesThe changes in cash flows from operating activities generally follow the results of operations as discussed in Financial and Operating Data and also are affected by changes in working capital.

Cash flows provided by operating activities in the first six months of 2013 increased $59.2 million from the comparable period in 2012, primarily due to higher cash flows from operations at the exploration and production business, partially offset by higher working capital requirements at the construction services business. Deferred income taxes decreased largely as a result of higher income taxes payable.

Investing activities Cash flows used in investing activities in the first six months of 2013 decreased $3.1 million from the comparable period in 2012. The decrease was primarily due to lower acquisition-related capital expenditures, primarily at the pipeline and energy services business. Partially offsetting the decrease in cash flows used in investing activities was higher ongoing capital expenditures of $43.0 million, including the diesel topping plant at the pipeline and energy services business, as well as electric generation projects at the electric business.

Financing activities Cash flows provided by financing activities in the first six months of 2013 increased $64.8 million from the comparable period in 2012, primarily due to higher issuance of long-term debt of $150.5 million, largely due to the issuance of $100.0 million of Senior Notes in February 2013; lower dividends paid of $30.7 million resulting from the Company accelerating the payment date for the quarterly common stock dividend from January 1, 2013 to December 31, 2012; as well as higher issuance of short-term borrowings of $29.6 million. Partially offsetting the increase in cash flows provided by financing activities was higher repayment of long-term debt of $155.9 million.

45

Defined benefit pension plans

There were no material changes to the Company's qualified noncontributory defined benefit pension plans from those reported in the 2012 Annual Report. For more information, see Note 17 and Part II, Item 7 in the 2012 Annual Report.

Capital expenditures

Net capital expenditures for the first six months of 2013 were $402.5 million and are estimated to be approximately $850 million for 2013. Estimated capital expenditures include:

• System upgrades

• Routine replacements

• Service extensions

• Routine equipment maintenance and replacements

• Buildings, land and building improvements

• Pipeline, gathering and other midstream projects

• Further development of existing properties, acquisition of additional leasehold acreage and exploratory drilling at the exploration and production segment

• Power generation and transmission opportunities, including certain costs for additional electric generating capacity

• Environmental upgrades

• The Company's proportionate share of the diesel topping plant at the pipeline and energy services segment

• Other growth opportunities

The Company continues to evaluate potential future acquisitions and other growth opportunities; however, they are dependent upon the availability of economic opportunities and, as a result, capital expenditures may vary significantly from the estimated 2013 capital expenditures referred to previously. The Company expects the 2013 estimated capital expenditures to be funded by various sources, including internally generated funds; the Company's credit facilities, as described later; and through the issuance of long-term debt and the Company's equity securities.

Capital resources

Certain debt instruments of the Company and its subsidiaries, including those discussed later, contain restrictive covenants and cross-default provisions. In order to borrow under the respective credit agreements, the Company and its subsidiaries must be in compliance with the applicable covenants and certain other conditions, all of which the Company and its subsidiaries, as applicable, were in compliance with at June 30, 2013. In the event the Company and its subsidiaries do not comply with the applicable covenants and other conditions, alternative sources of funding may need to be pursued. For additional information on the covenants, certain other conditions and cross-default provisions, see Part II, Item 8 - Note 9, in the 2012 Annual Report.

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The following table summarizes the outstanding credit facilities of the Company and its subsidiaries at June 30, 2013:

Company	Facility		Facility Limit			Amount Outstanding			Letters of Credit			Expiration Date
			(In millions)
MDU Resources Group, Inc.	Commercial paper/ Revolving credit agreement	(a)	$	125.0		$	55.5	(b)	$	—		10/4/17
Cascade Natural Gas Corporation	Revolving credit agreement		$	50.0	(c)	$	31.6		$	2.2	(d)	7/9/18
Intermountain Gas Company	Revolving credit agreement		$	65.0	(e)	$	25.4		$	—		7/13/18
Centennial Energy Holdings, Inc.	Commercial paper/ Revolving credit agreement	(f)	$	500.0		$	417.5	(b)	$	—		6/8/17
(a) The $125 million commercial paper program is supported by a revolving credit agreement with various banks totaling $125 million (provisions allow for increased borrowings, at the option of the Company on stated conditions, up to a maximum of $150 million). There were no amounts outstanding under the credit agreement. (b) Amount outstanding under commercial paper program. (c) Certain provisions allow for increased borrowings, up to a maximum of $75 million. (d) The outstanding letter of credit, as discussed in Note 19, reduces the amount available under the credit agreement. (e) Certain provisions allow for increased borrowings, up to a maximum of $90 million. (f) The $500 million commercial paper program is supported by a revolving credit agreement with various banks totaling $500 million (provisions allow for increased borrowings, at the option of Centennial on stated conditions, up to a maximum of $650 million). There were no amounts outstanding under the credit agreement.

The Company's and Centennial's respective commercial paper programs are supported by revolving credit agreements. While the amount of commercial paper outstanding does not reduce available capacity under the respective revolving credit agreements, the Company and Centennial do not issue commercial paper in an aggregate amount exceeding the available capacity under their credit agreements. The commercial paper borrowings may vary during the period, largely the result of fluctuations in working capital requirements due to the seasonality of the construction businesses.

The following includes information related to the preceding table.

MDU Resources Group, Inc. The Company's revolving credit agreement supports its commercial paper program. Commercial paper borrowings under this agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued commercial paper borrowings. The Company's objective is to maintain acceptable credit ratings in order to access the capital markets through the issuance of commercial paper. Downgrades in the Company's credit ratings have not limited, nor are currently expected to limit, the Company's ability to access the capital markets. If the Company were to experience a downgrade of its credit ratings, it may need to borrow under its credit agreement and may experience an increase in overall interest rates with respect to its cost of borrowings.

Prior to the maturity of the credit agreement, the Company expects that it will negotiate the extension or replacement of this agreement. If the Company is unable to successfully negotiate an extension of, or replacement for, the credit agreement, or if the fees on this facility become too expensive, which the Company does not currently anticipate, the Company would seek alternative funding.

Due to the $246.8 million after-tax noncash write-downs of oil and natural gas properties in 2012, earnings were insufficient by $19.8 million and $51.2 million to cover fixed charges for the 12 months ended June 30, 2013 and December 31, 2012, respectively. If the $246.8 million after-tax noncash write-downs were excluded, the coverage of fixed charges including preferred stock dividends would have been 4.5 times and 4.4 times for the 12 months ended June 30, 2013 and December 31, 2012, respectively.

The coverage of fixed charges including preferred stock dividends, that excludes the effect of the after-tax noncash write-downs of oil and natural gas properties is a non-GAAP financial measure. The Company believes that this non-GAAP financial measure is useful because the write-downs excluded are not indicative of the Company's cash flows available to meet its fixed charges obligations. The presentation of this additional information is not meant to be considered a substitute for the financial measure prepared in accordance with GAAP.

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Total equity as a percent of total capitalization was 57 percent, 63 percent and 60 percent at June 30, 2013 and 2012 and December 31, 2012, respectively. This ratio is calculated as the Company's total equity, divided by the Company's total capital. Total capital is the Company's total debt, including short-term borrowings and long-term debt due within one year, plus total equity. This ratio indicates how a company is financing its operations, as well as its financial strength.

The Company currently has a shelf registration statement on file with the SEC, under which the Company may issue and sell any combination of common stock and debt securities. The Company may sell all or a portion of such securities if warranted by market conditions and the Company's capital requirements. Any public offer and sale of such securities will be made only by means of a prospectus meeting the requirements of the Securities Act and the rules and regulations thereunder. The Company's board of directors currently has authorized the issuance and sale of up to an aggregate of $1.0 billion worth of such securities. The Company's board of directors reviews this authorization on a periodic basis and the aggregate amount of securities authorized may be increased in the future.

Cascade Natural Gas Corporation On July 9, 2013, Cascade entered into a revolving credit agreement which replaces the existing revolving credit agreement and extends the termination date to July 9, 2018. The credit agreement contains customary covenants and provisions, including a covenant of Cascade not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. Other covenants include restrictions on the sale of certain assets, limitations on indebtedness and the making of certain investments.

Cascade's credit agreement also contains cross-default provisions. These provisions state that if Cascade fails to make any payment with respect to any indebtedness or contingent obligation, in excess of a specified amount, under any agreement that causes such indebtedness to be due prior to its stated maturity or the contingent obligation to become payable, Cascade will be in default under the revolving credit agreement.

Intermountain Gas Company On July 15, 2013, Intermountain entered into a revolving credit agreement which replaces the existing revolving credit agreement and extends the termination date to July 13, 2018. The credit agreement contains customary covenants and provisions, including a covenant of Intermountain not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. Other covenants include restrictions on the sale of certain assets, limitations on indebtedness and the making of certain investments.

Intermountain's credit agreement also contains cross-default provisions. These provisions state that if Intermountain fails to make any payment with respect to any indebtedness or contingent obligation, in excess of a specified amount, under any agreement that causes such indebtedness to be due prior to its stated maturity or the contingent obligation to become payable, or certain conditions result in an early termination date under any swap contract that is in excess of a specified amount, then Intermountain will be in default under the revolving credit agreement.

Centennial Energy Holdings, Inc. Centennial's revolving credit agreement supports its commercial paper program. Commercial paper borrowings under this agreement are classified as long-term debt as they are intended to be refinanced on a long-term basis through continued commercial paper borrowings. Centennial's objective is to maintain acceptable credit ratings in order to access the capital markets through the issuance of commercial paper. Downgrades in Centennial's credit ratings have not limited, nor are currently expected to limit, Centennial's ability to access the capital markets. If Centennial were to experience a downgrade of its credit ratings, it may need to borrow under its credit agreement and may experience an increase in overall interest rates with respect to its cost of borrowings.

Prior to the maturity of the Centennial credit agreement, Centennial expects that it will negotiate the extension or replacement of this agreement, which provides credit support to access the capital markets. In the event Centennial is unable to successfully negotiate this agreement, or in the event the fees on this facility become too expensive, which Centennial does not currently anticipate, it would seek alternative funding.

Centennial entered into a note purchase agreement on June 27, 2013, and issued $50.0 million of Senior Notes with due dates ranging from June 2023 to June 2028 at a weighted average interest rate of 4.7 percent. Centennial contracted to issue an additional $25.0 million of Senior Notes under the agreement on November 1, 2013.

Off balance sheet arrangements

In connection with the sale of the Brazilian Transmission Lines, Centennial has agreed to guarantee payment of any indemnity obligations of certain of the Company's indirect wholly owned subsidiaries who are the sellers in three purchase and sale agreements for periods ranging up to 10 years from the date of sale. The guarantees were required by the buyers as a condition to the sale of the Brazilian Transmission Lines.

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Centennial continues to guarantee CEM's obligations under a construction contract for an electric generating facility near Hobbs, New Mexico. For more information, see Note 19.

Contractual obligations and commercial commitments

There are no material changes in the Company's contractual obligations relating to estimated interest payments, operating leases, purchase commitments, derivatives, asset retirement obligations and minimum funding requirements for its defined benefit plans for 2013 from those reported in the 2012 Annual Report.

The Company's contractual obligations relating to long-term debt at June 30, 2013 increased $261.8 million or 15 percent from December 31, 2012. As of June 30, 2013, the Company's contractual obligations related to long-term debt aggregated $2,006.8 million. The scheduled amounts of redemption (for the twelve months ended June 30, of each year listed) aggregate $69.1 million in 2014; $57.2 million in 2015; $404.2 million in 2016; $533.5 million in 2017; $118.4 million in 2018; and $824.4 million thereafter.

For more information on the Company's uncertain tax positions, see Note 15.

For more information on contractual obligations and commercial commitments, see Part II, Item 7 in the 2012 Annual Report.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

The Company is exposed to the impact of market fluctuations associated with commodity prices, interest rates and foreign currency. The Company has policies and procedures to assist in controlling these market risks and utilizes derivatives to manage a portion of its risk.

For more information on derivative instruments and commodity price risk, see Part II, Item 7A in the 2012 Annual Report, the Consolidated Statements of Comprehensive Income and Note 13.

Commodity price risk

Fidelity utilizes derivative instruments to manage a portion of the market risk associated with fluctuations in the price of oil and natural gas and basis differentials on forecasted sales of oil and natural gas production.

The following table summarizes derivative agreements entered into by Fidelity as of June 30, 2013. These agreements call for Fidelity to receive fixed prices and pay variable prices.

	(Forward notional volume and fair value in thousands)
		Weighted Average Fixed Price (Per Bbl/MMBtu)		Forward Notional Volume (Bbl/MMBtu)	Fair Value
Oil swap agreements maturing in 2013		$	97.76	1,656	$	4,347
Oil swap agreements maturing in 2014		$	92.69	1,086	$	1,476
Natural gas swap agreements maturing in 2013		$	3.78	10,420	$	1,157
Natural gas swap agreements maturing in 2014		$	4.13	7,300	$	1,845
Natural gas swap agreement maturing in 2015		$	4.28	3,650	$	518
		Weighted Average Floor/Ceiling Price (Per Bbl)		Forward Notional Volume (Bbl)	Fair Value
Oil collar agreements maturing in 2013		$92.50/$107.03		368	$	513

Interest rate risk

There were no material changes to interest rate risk faced by the Company from those reported in the 2012 Annual Report.

At June 30, 2013, the Company had no outstanding interest rate hedges.

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Foreign currency risk

The Company's equity method investment in ECTE is exposed to market risks from changes in foreign currency exchange rates between the U.S. dollar and the Brazilian Real. For more information, see Part II, Item 8 - Note 4 in the 2012 Annual Report.

At June 30, 2013, the Company had no outstanding foreign currency hedges.

ITEM 4. CONTROLS AND PROCEDURES

The following information includes the evaluation of disclosure controls and procedures by the Company's chief executive officer and the chief financial officer, along with any significant changes in internal controls of the Company.

Evaluation of disclosure controls and procedures

The term "disclosure controls and procedures" is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act. The Company's disclosure controls and other procedures are designed to provide reasonable assurance that information required to be disclosed in the reports that the Company files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC's rules and forms. The Company's disclosure controls and procedures include controls and procedures designed to provide reasonable assurance that information required to be disclosed is accumulated and communicated to management, including the Company's chief executive officer and chief financial officer, to allow timely decisions regarding required disclosure. The Company's management, with the participation of the Company's chief executive officer and chief financial officer, has evaluated the effectiveness of the Company's disclosure controls and procedures. Based upon that evaluation, the chief executive officer and the chief financial officer have concluded that, as of the end of the period covered by this report, such controls and procedures were effective at a reasonable assurance level.

Changes in internal controls

No change in the Company's internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) occurred during the quarter ended June 30, 2013, that has materially affected, or is reasonably likely to materially affect, the Company's internal control over financial reporting.

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PART II -- OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

For information regarding legal proceedings, see Note 19, which is incorporated herein by reference.

ITEM 1A. RISK FACTORS

This Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Exchange Act. Forward-looking statements are all statements other than statements of historical fact, including without limitation those statements that are identified by the words "anticipates," "estimates," "expects," "intends," "plans," "predicts" and similar expressions.

The Company is including the following factors and cautionary statements in this Form 10-Q to make applicable and to take advantage of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 for any forward-looking statements made by, or on behalf of, the Company. Forward-looking statements include statements concerning plans, objectives, goals, strategies, future events or performance, and underlying assumptions (many of which are based, in turn, upon further assumptions) and other statements that are other than statements of historical facts. From time to time, the Company may publish or otherwise make available forward-looking statements of this nature, including statements contained within Prospective Information. All these subsequent forward-looking statements, whether written or oral and whether made by or on behalf of the Company, also are expressly qualified by these factors and cautionary statements.

Forward-looking statements involve risks and uncertainties, which could cause actual results or outcomes to differ materially from those expressed. The Company's expectations, beliefs and projections are expressed in good faith and are believed by the Company to have a reasonable basis, including without limitation, management's examination of historical operating trends, data contained in the Company's records and other data available from third parties. Nonetheless, the Company's expectations, beliefs or projections may not be achieved or accomplished.

Any forward-looking statement contained in this document speaks only as of the date on which the statement is made, and the Company undertakes no obligation to update any forward-looking statement or statements to reflect events or circumstances that occur after the date on which the statement is made or to reflect the occurrence of unanticipated events. New factors emerge from time to time, and it is not possible for management to predict all of the factors, nor can it assess the effect of each factor on the Company's business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statement.

There are no material changes in the Company's risk factors from those reported in Part I, Item 1A - Risk Factors in the 2012 Annual Report other than the risk associated with the regulatory approval, permitting, construction, startup and/or operation of power generation facilities and the diesel topping plant; the risk related to environmental laws and regulations; and the risk associated with company operations that could be adversely impacted by global climate change initiatives to reduce GHG emissions. These factors and the other matters discussed herein are important factors that could cause actual results or outcomes for the Company to differ materially from those discussed in the forward-looking statements included elsewhere in this document.

Economic Risks

The regulatory approval, permitting, construction, startup and/or operation of power generation facilities and the diesel topping plant may involve unanticipated events or delays that could negatively impact the Company's business and its results of operations and cash flows.

The construction, startup and operation of power generation facilities and the diesel topping plant involve many risks, which may include: delays; breakdown or failure of equipment; inability to obtain required governmental permits and approvals; inability to complete financing; inability to negotiate acceptable equipment acquisition, construction, fuel and crude oil supply, off-take, transmission, transportation or other material agreements; changes in markets and market prices for power, crude oil and refined products; cost increases; as well as the risk of performance below expected levels of output or efficiency. Such unanticipated events could negatively impact the Company's business, its results of operations and cash flows.

In March 2013, construction began on Dakota Prairie Refinery, which has a targeted in-service date in late 2014. The previously mentioned risks could negatively affect the results of operations and cash flows of the pipeline and energy services segment.

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Environmental Risks

The Company's operations are subject to environmental laws and regulations that may increase costs of operations, impact or limit business plans, or expose the Company to environmental liabilities.

The Company is subject to environmental laws and regulations affecting many aspects of its present and future operations, including air quality, water quality, waste management and other environmental considerations. These laws and regulations can result in increased capital, operating and other costs, cause delays as a result of litigation and administrative proceedings, and create compliance, remediation, containment, monitoring and reporting obligations, particularly with regard to laws relating to electric generation operations and oil and natural gas development. These laws and regulations generally require the Company to obtain and comply with a wide variety of environmental licenses, permits, inspections and other approvals. Although the Company strives to comply with all applicable environmental laws and regulations, public and private entities, as well as private individuals, may seek injunctive relief or other remedies to enforce applicable environmental laws and regulations with which they have differing interpretations of the Company's legal or regulatory compliance. The Company cannot predict the outcome (financial or operational) of any related litigation or administrative proceedings that may arise.

Existing environmental laws and regulations may be revised and new laws and regulations seeking to protect the environment may be adopted or become applicable to the Company. These laws and regulations could require the Company to limit the use or output of certain facilities, restrict the use of certain fuels, install pollution controls, remediate environmental contamination, remove or reduce environmental hazards, or prevent or limit the development of resources. Revised or additional laws and regulations that result in increased compliance costs or additional operating restrictions, particularly if those costs are not fully recoverable from customers, could have a material adverse effect on the Company's results of operations and cash flows.

The EPA has issued draft regulations that outline several possible approaches for coal combustion residuals management under the RCRA. One approach, designating coal ash as a hazardous waste, would significantly change the manner and increase the costs of managing coal ash at five plants that supply electricity to customers of Montana-Dakota. This designation also could significantly increase costs for Knife River, which beneficially uses fly ash as a cement replacement in ready-mixed concrete and road base applications.

In December 2011, the EPA finalized the Mercury and Air Toxics rule that will require reductions in mercury and other air emissions from coal- and oil-fired electric utility steam generating units. Montana-Dakota evaluated the pollution control technologies needed at its electric generation resources to comply with this final rule and determined that additional particulate matter control is required to control non-mercury metal emissions at the Lewis & Clark Station near Sidney, Montana. Controls must be installed by April 16, 2015, or April 16, 2016, if a one-year extension is granted for installation.

Hydraulic fracturing is an important common practice used by Fidelity that involves injecting water; sand; guar, a water thickening agent; and trace amounts of chemicals under pressure into rock formations to stimulate oil, NGL and natural gas production. Fidelity is following state regulations for well drilling and completion, including regulations related to hydraulic fracturing and disposing of recovered fluids. Fracturing fluid constituents are reported on state or national websites. The EPA is developing a study to review the potential effects of hydraulic fracturing on underground sources of drinking water; the results of that study could impact future legislation or regulation. The BLM has released draft well stimulation regulations for hydraulic fracturing operations. If implemented, the BLM regulations would only affect Fidelity's operations on BLM-administered lands. If adopted as proposed, the BLM regulations, along with other legislative initiatives and regulatory studies, proceedings or initiatives at federal or state agencies that focus on the hydraulic fracturing process, could result in additional compliance, reporting and disclosure requirements. Future legislation or regulation could increase compliance and operating costs, as well as delay or inhibit the Company's ability to develop its oil, NGL and natural gas reserves.

On August 16, 2012, the EPA published a final NSPS rule for the oil and natural gas industry. The NSPS rule phases in over two years. The first phase was effective October 15, 2012, and primarily covers natural gas wells that are hydraulically fractured. Under the new rule, gas vapors or emissions from the natural gas wells must be captured or combusted utilizing a high efficiency device. Additional reporting requirements and control devices covering oil and natural gas production equipment will be phased in for certain new oil and gas facilities with a final effective date of January 1, 2015. This new rule's impacts on Fidelity, WBI Energy Transmission and WBI Energy Midstream are not expected to be material and are likely to include implementation of recordkeeping, reporting and testing requirements and the acquisition and installation of required equipment.

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Initiatives to reduce GHG emissions could adversely impact the Company's operations.

Concern that GHG emissions are contributing to global climate change has led to international, federal and state legislative and regulatory proposals to reduce or mitigate the effects of GHG emissions. On June 25, 2013, President Obama released his Climate Action Plan for the U.S. in which he states his goal to reduce GHG emissions "in the range of 17 percent" below 2005 levels by 2020. The president issued a memorandum to the EPA on the same day, instructing the EPA to re-propose the GHG NSPS rule for new electric generation units no later than September 20, 2013. This new rule will take the place of the rule proposed in 2012 for new electric generation units that the EPA did not finalize. The president also directed the EPA to develop a GHG NSPS standard for existing fossil fuel-fired electric generation units by June 1, 2014, with finalization by June 1, 2015. The president did not specify a GHG standard or the format of the standard.

The primary GHG emitted from the Company's operations is carbon dioxide from combustion of fossil fuels at Montana-Dakota's electric generating facilities, particularly its coal-fired facilities. Approximately 70 percent of Montana-Dakota's owned generating capacity and more than 90 percent of the electricity it generates is from coal-fired facilities. Montana-Dakota also owns approximately 100 MW of natural gas- and oil-fired peaking plants.

Montana-Dakota's existing electric generating facilities are expected to be subject to GHG laws or regulations within the next few years through a GHG NSPS for existing and modified units. Implementation of treaties, legislation or regulations to reduce GHG emissions could affect Montana-Dakota's electric utility operations by requiring expanded energy conservation efforts or increased development of renewable energy sources, as well as other mandates that could significantly increase capital expenditures and operating costs. If Montana-Dakota does not receive timely and full recovery of GHG emission compliance costs from its customers, then such costs could have an adverse impact on the results of its operations.

In addition to Montana-Dakota's electric generation operations, the GHG emissions from the Company's other operations are monitored, analyzed and reported as required in accordance with applicable laws and regulations. The Company monitors the development of GHG regulations and the potential for GHG regulations to impact all existing and future operations.

Due to the uncertain availability of technologies to control GHG emissions and the unknown obligations that potential GHG emission legislation or regulations may create, the Company cannot determine the potential financial impact on its operations.

ITEM 4. MINE SAFETY DISCLOSURES

For information regarding mine safety violations or other regulatory matters required by Section 1503(a) of the Dodd-Frank Act and Item 104 of Regulation S-K, see Exhibit 95 to this Form 10-Q, which is incorporated herein by reference.

ITEM 6. EXHIBITS

See the index to exhibits immediately preceding the exhibits filed with this report.

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SIGNATURES

Pursuant to the requirements of the Exchange Act, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

		MDU RESOURCES GROUP, INC.
DATE:	August 7, 2013	BY:	/s/ Doran N. Schwartz
			Doran N. Schwartz
			Vice President and Chief Financial Officer
		BY:	/s/ Nicole A. Kivisto
			Nicole A. Kivisto
			Vice President, Controller and Chief Accounting Officer

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EXHIBIT INDEX

Exhibit No.
+10(a)	Director Compensation Policy, as amended May 16, 2013
+10(b)	MDU Resources Group, Inc. Section 16 Officers and Directors with Indemnification Agreements Chart, as of June 30, 2013
12	Computation of Ratio of Earnings to Fixed Charges and Combined Fixed Charges and Preferred Stock Dividends
31(a)	Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
31(b)	Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
32	Certification of Chief Executive Officer and Chief Financial Officer furnished pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
95	Mine Safety Disclosures
101	The following materials from MDU Resources Group, Inc.'s Quarterly Report on Form 10-Q for the quarter ended June 30, 2013, formatted in XBRL (eXtensible Business Reporting Language): (i) the Consolidated Statements of Income, (ii) the Consolidated Statements of Comprehensive Income, (iii) the Consolidated Balance Sheets, (iv) the Consolidated Statements of Cash Flows and (v) the Notes to Consolidated Financial Statements, tagged in summary and detail

+ Management contract, compensatory plan or arrangement.

MDU Resources Group, Inc. agrees to furnish to the SEC upon request any instrument with respect to long-term debt that MDU Resources Group, Inc. has not filed as an exhibit pursuant to the exemption provided by Item 601(b)(4)(iii)(A) of Regulation S-K.

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