10-Q

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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 March 31, 2011
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 001-31239

MARKWEST ENERGY PARTNERS, L.P.
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization) 27-0005456
(IRS Employer
Identification No.)

1515 Arapahoe Street, Tower 1, Suite 1600, Denver, Colorado 80202-2137
(Address of principal executive offices)

Registrant's telephone number, including area code: 303-925-9200

        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 (§232.405 of this chapter) 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 definitions of "large accelerated filer," "accelerated filer," and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer ý Accelerated filer o Non-accelerated filer o
(Do not check if a
smaller reporting company) Smaller reporting company o

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

        The number of the registrant's common units outstanding as of May 2, 2011, was 75,160,105.

PART I—FINANCIAL INFORMATION
Item 1.	Financial Statements	2
	Unaudited Condensed Consolidated Balance Sheets at March 31, 2011 and December 31, 2010	2
	Unaudited Condensed Consolidated Statements of Operations for the three months ended March 31, 2011 and 2010	3
	Unaudited Condensed Consolidated Statements of Changes in Equity for the three months ended March 31, 2011 and 2010	4
	Unaudited Condensed Consolidated Statements of Cash Flows for the three months ended March 31, 2011 and 2010	5
	Unaudited Notes to the Condensed Consolidated Financial Statements	6
Item 2.	Management's Discussion and Analysis of Financial Condition and Results of Operations	34
Item 3.	Quantitative and Qualitative Disclosures about Market Risk	48
Item 4.	Controls and Procedures	51
PART II—OTHER INFORMATION
Item 1.	Legal Proceedings	52
Item 6.	Exhibits	52
SIGNATURES		54

        Throughout this document we make statements that are classified as "forward-looking." Please refer to the "Forward-Looking Statements" included in Part I, Item 2 for an explanation of these types of assertions. Also, in this document, unless the context requires otherwise, references to "we," "us," "our," "MarkWest Energy" or the "Partnership" are intended to mean MarkWest Energy Partners, L.P., and its consolidated subsidiaries. References to "MarkWest Hydrocarbon" or the "Corporation" are intended to mean MarkWest Hydrocarbon, Inc., a wholly-owned taxable subsidiary of the Partnership.

Glossary of Terms

Bbl	Barrel
Bbl/d	Barrels per day
Credit Facility	Revolving credit facility as provided under the Partnership's amended and restated credit agreement entered into in July 2010
Dth/d	Dekatherms per day
EPA	Environmental Protection Agency
FASB	Financial Accounting Standards Board
FERC	Federal Energy Regulatory Commission
GAAP	Accounting principles generally accepted in the United States of America
Mcf/d	One thousand cubic feet of natural gas per day
MMBtu	One million British thermal units, an energy measurement
MMBtu/d	One million British thermal units per day
MMcf/d	One million cubic feet of natural gas per day
Net operating margin (a non-GAAP financial measure)	Segment revenue, excluding any derivative gain (loss), less purchased product costs, excluding any derivative gain (loss)
NGL	Natural gas liquids, such as ethane, propane, butanes and natural gasoline
N/A	Not applicable
OTC	Over-the-Counter
SEC	Securities and Exchange Commission
SMR	Steam methane reformer, operated by a third party and located at the Javelina gas processing and fractionation facility in Corpus Christi, Texas
TSR	Total shareholder return
WTI	West Texas Intermediate
VIE	Variable interest entity
2002 LTIP	2002 Long-Term Incentive Plan
2006 Hydrocarbon Plan	2006 Hydrocarbon Stock Incentive Plan
2008 LTIP	2008 Long-Term Incentive Plan

1

PART I—FINANCIAL INFORMATION

Item 1.    Financial Statements

MARKWEST ENERGY PARTNERS, L.P.

Condensed Consolidated Balance Sheets

(unaudited, in thousands)

					March 31, 2011			December 31, 2010
				ASSETS
Current assets:
	Cash and cash equivalents ($9,037 and $2,913, respectively)				$	73,152		$	67,450
	Receivables, net ($14,288 and $43,783, respectively)					165,718			179,209
	Inventories ($4,832 and $8,431, respectively)					15,922			23,432
	Fair value of derivative instruments					6,138			4,345
	Deferred income taxes					16,090			16,090
	Other current assets ($77 and $272, respectively)					10,678			8,020
		Total current assets				287,698			298,546
Property, plant and equipment ($928,866 and $849,986, respectively)						2,849,638			2,613,027
Less: accumulated depreciation ($46,434 and $38,169, respectively)						(327,286	)		(294,003	)
		Total property, plant and equipment, net				2,522,352			2,319,024
Other long-term assets:
	Restricted cash ($28,052 and $28,001, respectively)					28,052			28,001
	Investment in unconsolidated affiliate					28,149			28,688
	Intangibles, net of accumulated amortization of $135,367 and $124,568, respectively					636,568			613,578
	Goodwill					67,918			9,421
	Deferred financing costs, net of accumulated amortization of $11,432 and $11,445, respectively					35,158			32,901
	Deferred contract cost, net of accumulated amortization of $2,028 and $1,950, respectively					1,222			1,300
	Fair value of derivative instruments					3,037			417
	Deferred income taxes					5,425			—
	Other long-term assets ($378 and $383, respectively)					1,807			1,486
		Total assets			$	3,617,386		$	3,333,362
			LIABILITIES AND EQUITY
Current liabilities:
	Accounts payable ($10,673 and $5,945, respectively)				$	130,654		$	122,473
	Accrued liabilities ($48,750 and $64,713, respectively)					134,030			153,869
	Deferred income taxes					11			11
	Fair value of derivative instruments					102,810			65,489
		Total current liabilities				367,505			341,842
Deferred income taxes						1,666			10,427
Fair value of derivative instruments						114,211			66,290
Long-term debt, net of discounts of $1,595 and $1,566, respectively						1,474,757			1,273,434
Other long-term liabilities ($157 and $154, respectively)						113,167			105,349
Commitments and contingencies (Note 11)
Equity:
	MarkWest Energy Partners, L.P. partners' capital (75,160 and 71,440 common units issued and outstanding, respectively)					1,076,773			1,070,503
	Non-controlling interest in consolidated subsidiaries					469,307			465,517
		Total equity				1,546,080			1,536,020
		Total liabilities and equity			$	3,617,386		$	3,333,362

        Asset and liability amounts in parentheses represent the portion of the consolidated balance attributable to VIEs.

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

2

MARKWEST ENERGY PARTNERS, L.P.

Condensed Consolidated Statements of Operations

(unaudited, in thousands, except per unit amounts)

			Three months ended March 31,
			2011			2010
Revenue:
	Revenue		$	348,900		$	315,615
	Derivative loss			(85,679	)		(7,236	)
		Total revenue		263,221			308,379
Operating expenses:
	Purchased product costs			153,629			144,296
	Derivative loss related to purchased product costs			19,394			13,389
	Facility expenses			39,424			37,905
	Derivative gain related to facility expenses			(3,011	)		(806	)
	Selling, general and administrative expenses			21,712			21,508
	Depreciation			34,364			28,187
	Amortization of intangible assets			10,817			10,193
	Loss (gain) on disposal of property, plant and equipment			2,099			(9	)
	Accretion of asset retirement obligations			87			143
		Total operating expenses		278,515			254,806
		(Loss) income from operations		(15,294	)		53,573
Other (expense) income:
	Loss from unconsolidated affiliate			(539	)		(68	)
	Interest income			89			386
	Interest expense			(28,263	)		(23,782	)
	Amortization of deferred financing costs and discount (a component of interest expense)			(1,428	)		(2,612	)
	Derivative gain related to interest expense			—			1,871
	Loss on redemption of debt			(43,328	)		—
	Miscellaneous (expense) income, net			(38	)		1,062
		(Loss) income before provision for income tax		(88,801	)		30,430
Provision for income tax (benefit) expense:
	Current			56			5,798
	Deferred			(14,186	)		(1,372	)
		Total provision for income tax		(14,130	)		4,426
		Net (loss) income		(74,671	)		26,004
Net income attributable to non-controlling interest				(9,358	)		(4,494	)
		Net (loss) income attributable to the Partnership	$	(84,029	)	$	21,510
Net (loss) income attributable to the Partnership's common unitholders per common unit (Note 14):
	Basic		$	(1.13	)	$	0.32
	Diluted		$	(1.13	)	$	0.32
Weighted average number of outstanding common units:
	Basic			74,531			66,453
	Diluted			74,531			66,453
Cash distribution declared per common unit			$	0.65		$	0.64

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

3

MARKWEST ENERGY PARTNERS, L.P.

Condensed Consolidated Statements of Changes in Equity

(unaudited, in thousands)

	MarkWest Energy Partners, L.P. Unitholders
	Common Units		Partners' Capital			Non-controlling Interest			Total
December 31, 2010		71,440	$	1,070,503		$	465,517		$	1,536,020
Share-based compensation activity		270		314			—			314
Excess tax benefits related to share-based compensation		—		1,096			—			1,096
Distributions paid		—		(49,274	)		(13,568	)		(62,842	)
Issuance of units in public offering, net of offering costs		3,450		138,163			—			138,163
Contributions to MarkWest Liberty Midstream joint venture		—		—			8,000			8,000
Net (loss) income		—		(84,029	)		9,358			(74,671	)
March 31, 2011		75,160	$	1,076,773		$	469,307		$	1,546,080

	MarkWest Energy Partners, L.P. Unitholders
	Common Units		Partners' Capital			Non-controlling Interest			Total
December 31, 2009		66,275	$	1,096,654		$	282,739		$	1,379,393
Share-based compensation activity		271		3,622			—			3,622
Excess tax benefits related to share-based compensation		—		97			—			97
Distributions paid		—		(42,866	)		(1,270	)		(44,136	)
Contributions to MarkWest Liberty Midstream joint venture		—		—			42,220			42,220
Net income		—		21,510			4,494			26,004
March 31, 2010		66,546	$	1,079,017		$	328,183		$	1,407,200

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

4

MARKWEST ENERGY PARTNERS, L.P.

Condensed Consolidated Statements of Cash Flows

(unaudited, in thousands)

				Three months ended March 31,
				2011			2010
Cash flows from operating activities:
Net (loss) income				$	(74,671	)	$	26,004
	Adjustments to reconcile net (loss) income to net cash provided by operating activities:
		Depreciation			34,364			28,187
		Amortization of intangible assets			10,817			10,193
		Loss on redemption of debt			43,328			—
		Amortization of deferred financing costs and discount			1,428			2,612
		Accretion of asset retirement obligations			87			143
		Amortization of deferred contract cost			78			78
		Phantom unit compensation expense			5,636			6,285
		Equity in loss of unconsolidated affiliate			539			68
		Unrealized loss on derivative instruments			80,829			2,269
		Loss (gain) on disposal of property, plant and equipment			2,099			(9	)
		Deferred income taxes			(14,186	)		(1,372	)
	Changes in operating assets and liabilities, net of working capital acquired:
		Receivables			13,751			(5,968	)
		Inventories			9,148			9,149
		Other current assets			(2,658	)		6,096
		Accounts payable and accrued liabilities			(3,024	)		28,507
		Other long-term assets			(372	)		36
		Other long-term liabilities			8,126			2,082
			Net cash provided by operating activities		115,319			114,360
Cash flows from investing activities:
		Capital expenditures			(113,652	)		(95,322	)
		Acquisitions			(230,728	)		—
		Proceeds from disposal of property, plant and equipment			2,759			292
			Net cash used in investing activities		(341,621	)		(95,030	)
Cash flows from financing activities:
		Proceeds from revolving credit facility			307,600			135,604
		Payments of revolving credit facility			(168,400	)		(141,904	)
		Proceeds from long-term debt			499,000			—
		Payments of long-term debt			(437,848	)		—
		Payments of premiums on redemption of long-term debt			(39,520	)		—
		Payments for debt issuance costs, deferred financing costs and registration costs			(6,524	)		—
		Contributions to MarkWest Liberty Midstream joint venture			8,000			42,220
		Payments of SMR liability			(452	)		(58	)
		Proceeds from public equity offering, net			138,163			—
		Cash paid for taxes related to net settlement of share-based payment awards			(6,269	)		(3,730	)
		Excess tax benefits related to share-based compensation			1,096			97
		Payment of distributions to common unitholders			(49,274	)		(42,866	)
		Payment of distributions to non-controlling interest			(13,568	)		(1,270	)
			Net cash provided by (used in) financing activities		232,004			(11,907	)
Net increase in cash					5,702			7,423
Cash and cash equivalents at beginning of year					67,450			97,752
Cash and cash equivalents at end of period				$	73,152		$	105,175

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

5

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements

(unaudited)

1. Organization and Basis of Presentation

        MarkWest Energy Partners, L.P. was formed in 2002 as a Delaware limited partnership. The Partnership is engaged in the gathering, transportation and processing of natural gas; the transportation, fractionation, marketing and storage of NGLs; and the gathering and transportation of crude oil. The Partnership has extensive natural gas gathering, processing and transmission operations in the southwest, Gulf Coast, and northeast regions of the United States, including the Marcellus Shale, and is the largest natural gas processor and fractionator in the Appalachian region.

        These unaudited condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the SEC for interim financial reporting. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. These condensed consolidated financial statements should be read in conjunction with the Partnership's consolidated financial statements included in the Partnership's Annual Report on Form 10-K for the year ended December 31, 2010. In management's opinion, the Partnership has made all adjustments necessary for a fair presentation of its results of operations, financial position and cash flows for the periods shown. These adjustments are of a normal recurring nature. Finally, results for the three months ended March 31, 2011 are not necessarily indicative of results for the full year 2011, or any other future period.

        The Partnership's unaudited condensed consolidated financial statements include all majority-owned or majority-controlled subsidiaries. In addition, MarkWest Liberty Midstream & Resources L.L.C. ("MarkWest Liberty Midstream") and MarkWest Pioneer, L.L.C. ("MarkWest Pioneer"), variable interest entities for which the Partnership has been determined to be the primary beneficiary, are included in the condensed consolidated financial statements (see Note 4). All significant intercompany investments, accounts and transactions have been eliminated. Investments in which the Partnership exercises significant influence but does not control, and is not the primary beneficiary, are accounted for using the equity method.

2. Recent Accounting Pronouncements

        In September 2009, the FASB amended the accounting guidance for revenue recognition for multiple-deliverable arrangements. The amended guidance establishes a hierarchy for determining the selling price of each individual deliverable and eliminates the residual value method of allocating the selling price. The amended guidance was effective for the Partnership prospectively for all revenue arrangements entered into or materially modified on or after January 1, 2011. The amendment did not have a material effect on the Partnership's condensed consolidated financial statements.

3. Business Combination

Langley Acquisition

        On February 1, 2011, the Partnership acquired natural gas processing and NGL transportation assets from EQT Gathering, LLC, a subsidiary of EQT Corporation (together with all of its affiliates, "EQT"), for a cash purchase price of approximately $230.7 million, subject to customary purchase price adjustments. The assets acquired include natural gas processing facilities located near Langley, Kentucky, consisting of a cryogenic natural gas processing plant with a capacity of approximately 100 MMcf/d and a refrigeration natural gas processing plant with a capacity of approximately

6

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

3. Business Combination (Continued)

75 MMcf/d (together, the "Langley Processing Facilities"), a partially constructed NGL pipeline (the "Ranger Pipeline") that will extend through parts of Kentucky and West Virginia, and certain other related assets. The acquired assets do not include certain residue gas compression and transportation facilities at the same location as the Langley Processing Facilities. This acquisition is referred to as the Langley Acquisition. In connection with the Langley Acquisition, the Partnership will complete the construction of the Ranger Pipeline to connect the Langley Processing Facilities to the Partnership's existing pipeline that transports NGLs to its Siloam fractionation facility in South Shore, Kentucky.

        Concurrently with the closing of the Langley Acquisition, the Partnership entered into a long-term agreement to process certain natural gas owned or controlled by EQT at the Langley Processing Facilities. The processing agreement requires the Partnership to install an additional cryogenic natural gas processing plant with a capacity of at least 60 MMcf/d by mid-2012. The Partnership will fractionate the NGLs produced at the Langley Processing Facilities at its Siloam facility and will market the fractionated products on behalf of EQT in accordance with a long-term NGL exchange and marketing agreement. As a result of the acquisition, the Partnership has significantly expanded its midstream operations in the liquids-rich gas areas of the Appalachian Basin.

        The Langley Acquisition is accounted for as a business combination. The total purchase price is allocated to the identifiable assets acquired and liabilities assumed based on the estimated fair values at the acquisition date. The remaining purchase price in excess of the fair value of the identifiable assets and liabilities is recorded as goodwill. The acquired assets and the related results of operations are included in the Partnership's Northeast segment.

        The Partnership is in the process of finalizing the fair value estimates of the acquired assets and liabilities, thus the purchase price allocation is subject to further adjustment, which could impact depreciation and amortization expense. The following table summarizes the preliminary purchase price allocation for the Langley Acquisition (in thousands):

Property, plant and equipment		$	136,525
Goodwill			58,497
Intangibles			33,900
Inventories			1,806
	Total	$	230,728

        The goodwill recognized from the Langley Acquisition results primarily from the benefits associated with combining the acquired assets with the Partnership's existing assets and operations. Management believes that the primary item that generated the goodwill is the Partnership's ability to continue to grow its business in the liquids-rich gas areas of the Appalachian Basin and access additional markets in a competitive environment through the processing rights for a large area of dedicated acreage and the expanded midstream infrastructure obtained in the Langley Acquisition. All of the goodwill is deductible for tax purposes.

        Intangible assets consist of an identifiable customer contract and relationship. The acquired intangibles will be amortized on a straight-line basis over the estimated remaining useful life of approximately twelve years.

7

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

3. Business Combination (Continued)

        The results of operations from the Langley Acquisition are included in the condensed consolidated financial statements from the acquisition date. Revenue and net income related to the Langley Acquisition was approximately $3.9 million and $1.4 million, respectively, for the quarter ended March 31, 2011.

        Pro forma financial results that give effect to the Langley Acquisition are not presented as it is impracticable to obtain the necessary information. EQT did not operate the acquired assets as a stand-alone business, and therefore historical financial information that is consistent with the operations under the current agreements is not available or meaningful.

4. Variable Interest Entities

MarkWest Liberty Midstream

        MarkWest Liberty Midstream operates in the natural gas midstream business in and around the Marcellus Shale in western Pennsylvania and northern West Virginia. Effective January 1, 2011, equity interests in the entity are owned 51% by the Partnership and 49% by M&R MWE Liberty, LLC ("M&R"), an affiliate of The Energy & Minerals Group and its affiliated funds.

        As of March 31, 2011, the capital contributed to MarkWest Liberty Midstream is disproportionate to each member's respective ownership interest. The cumulative capital contributed by M&R exceeded its ownership interest by $43.0 million. Under the terms of the joint venture agreement, M&R received a special $1.1 million allocation of net income from MarkWest Liberty Midstream during the first quarter of 2011 due to its excess contributions. The non-cash allocation is recorded in Net income attributable to non-controlling interest.

MarkWest Pioneer

        MarkWest Pioneer is the owner and operator of the Arkoma Connector Pipeline. Equity interests in the entity are shared equally by the Partnership and Arkoma Pipeline Partners, LLC.

8

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

4. Variable Interest Entities (Continued)

Financial Statement Impact of VIEs

        As the primary beneficiary of MarkWest Liberty Midstream and MarkWest Pioneer, the Partnership consolidates the entities and recognizes non-controlling interests. The following tables show the assets and liabilities attributable to VIEs as of March 31, 2011 and December 31, 2010 (in thousands):

		As of March 31, 2011
		MarkWest Liberty Midstream		MarkWest Pioneer		Total
ASSETS
Cash and cash equivalents		$	7,369	$	1,668	$	9,037
Receivables, net			12,880		1,408		14,288
Inventories			4,832		—		4,832
Other current assets			77		—		77
Property, plant and equipment, net of accumulated depreciation of $35,572 and $10,862, respectively			736,956		145,476		882,432
Restricted cash			28,052		—		28,052
Other long-term assets			275		103		378
	Total assets	$	790,441	$	148,655	$	939,096
LIABILITIES
Accounts payable		$	10,593	$	80	$	10,673
Accrued liabilities			48,083		667		48,750
Other long-term liabilities			88		69		157
	Total liabilities	$	58,764	$	816	$	59,580

		As of December 31, 2010
		MarkWest Liberty Midstream		MarkWest Pioneer		Total
ASSETS
Cash and cash equivalents		$	—	$	2,913	$	2,913
Receivables, net			42,181		1,602		43,783
Inventories			8,431		—		8,431
Other current assets			271		1		272
Property, plant and equipment, net of accumulated depreciation of $28,869 and $9,300, respectively			664,778		147,039		811,817
Restricted cash			28,001		—		28,001
Other long-term assets			281		102		383
	Total assets	$	743,943	$	151,657	$	895,600
LIABILITIES
Accounts payable		$	5,945	$	—	$	5,945
Accrued liabilities			63,450		1,263		64,713
Other long-term liabilities			86		68		154
	Total liabilities	$	69,481	$	1,331	$	70,812

9

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

4. Variable Interest Entities (Continued)

        The assets of the VIEs are the property of the respective entities and are not available to the Partnership for any other purpose, including as collateral for its secured debt (see Note 9 and Note 16). VIE asset balances can only be used to settle obligations of each respective VIE. The liabilities of the VIEs do not represent additional claims against the Partnership's general assets, and the creditors or beneficial interest holders of the VIE do not have recourse to the general credit of the Partnership. The Partnership's Liberty segment includes the results of operations of MarkWest Liberty Midstream and the Partnership's Southwest segment includes the results of operations of MarkWest Pioneer (see Note 15). The cash flow information for MarkWest Liberty Midstream and MarkWest Pioneer comprise substantially all of the cash flow information of the Partnership's non-guarantor subsidiaries (see Note 16). The Partnership's maximum exposure to loss as a result of its involvement with the VIEs includes its equity investment, any additional capital contribution commitments and any operating expense incurred by the subsidiary operator in excess of its compensation received for the performance of the operating services. The Partnership did not provide any financial support to the VIEs that it was not contractually obligated to provide during the three months ended March 31, 2011 and 2010.

5. Derivative Financial Instruments

Commodity Derivatives

        NGL and natural gas prices are volatile and are impacted by changes in fundamental supply and demand, as well as market uncertainty, availability of NGL transportation and fractionation capacity and a variety of additional factors that are beyond the Partnership's control. The Partnership's profitability is directly affected by prevailing commodity prices primarily as a result of processing or conditioning at its processing plants or third-party processing plants, purchasing and selling or gathering and transporting volumes of natural gas at index-related prices and the cost of third-party transportation and fractionation services. To the extent that commodity prices influence the level of drilling activity, such prices also affect profitability. To protect itself financially against adverse price movements and to maintain more stable and predictable cash flows so that the Partnership can meet its cash distribution objectives, debt service and capital expenditures, the Partnership executes a hedging strategy governed by the risk management policy approved by the General Partner's board of directors (the "Board"). The Partnership has a committee comprised of senior management that oversees risk management activities, continually monitors the risk management program and adjusts its strategy as conditions warrant. The Partnership enters into certain derivative contracts to reduce the risks associated with unfavorable changes in the prices of natural gas, NGLs and crude oil. Derivative contracts utilized are swaps and options traded on the OTC market. The risk management policy does not allow for speculative derivative contracts.

        To mitigate its cash flow exposure to fluctuations in the price of NGLs, the Partnership has entered into derivative financial instruments relating to the future price of NGLs and crude oil. Generally the Partnership hedges its NGL price risk using crude oil as NGL financial markets lack adequate liquidity and historically there has been a strong relationship between changes in NGL and crude oil prices. The pricing relationship between NGLs and crude oil may vary in certain periods due to various market conditions. In periods where NGL prices and crude oil prices are not consistent with the historical relationship, the Partnership incurs increased risk and additional gains or losses. The Partnership enters into NGL derivative contracts when adequate market liquidity exists.

10

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

5. Derivative Financial Instruments (Continued)

        To mitigate its cash flow exposure to fluctuations in the price of natural gas, the Partnership primarily utilizes derivative financial instruments relating to the future price of natural gas and takes into account the partial offset of its long and short gas positions resulting from normal operating activities.

        As a result of its current derivative positions, the Partnership has mitigated a portion of its expected commodity price risk through the fourth quarter of 2013. For entities that are not wholly owned by the Partnership, commodity risk is mitigated only for the Partnership's ownership interest. The Partnership would be exposed to additional commodity risk in certain situations such as if producers under deliver or over deliver product or when processing facilities are operated in different recovery modes. In the event the Partnership has derivative positions in excess of the product delivered or expected to be delivered, the excess derivative positions may be terminated.

        The Partnership enters into derivative contracts primarily with financial institutions that are participating members of the Credit Facility as collateral is not posted by the Partnership as the participating members have a collateral position in substantially all the wholly-owned assets of the Partnership. All of the Partnership's financial derivative positions are currently with participating bank group members. Management conducts a standard credit review on counterparties and the Partnership has agreements containing collateral requirements. For all participating bank group members, collateral requirements do not exist when a derivative contract favors the Partnership. The Partnership uses standardized agreements that allow for offset of positive and negative exposures (master netting arrangements).

        The Partnership records derivative contracts at fair value in the Condensed Consolidated Balance Sheets and has not elected hedge accounting or the normal purchases and normal sales designation which may cause volatility in the Condensed Consolidated Statements of Operations as the Partnership recognizes in current earnings all unrealized gains and losses from the mark to market on derivative activity.

        As of March 31, 2011, the Partnership had the following outstanding commodity contracts that were entered into to economically hedge future sales of NGLs or future purchases of natural gas.

Derivative contracts not designated as hedging instruments	Notional quantity (net)
Crude Oil (bbl)		8,562,749
Natural Gas (MMBtu)		14,528,806

Embedded Derivatives in Commodity Contracts

        The Partnership has a commodity contract with a producer in the Appalachia region that creates a floor on the frac spread for gas purchases of 9,000 Dth/d. The commodity contract is a component of a broader regional arrangement that also includes a keep-whole processing agreement. This contract is accounted for as an embedded derivative and is recorded at fair value. The changes in fair value of this commodity contract are based on the difference between the contractual and index pricing and are recorded in earnings through Derivative loss related to purchased product costs. In February 2011, the Partnership executed agreements with the producer to extend the commodity contract and the related

11

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

5. Derivative Financial Instruments (Continued)

processing agreement from March 31, 2015 to December 31, 2022. As of March 31, 2011, the estimated fair value of this contract was a liability of $108.2 million and the recorded value was $54.7 million. The recorded liability does not include the fair value of the commodity contract related to the extended period from April 1, 2015 to December 31, 2022. In accordance with GAAP for non-option embedded derivatives, the fair value of this extended portion of the commodity contract at its inception of February 1, 2011 is deemed to be allocable to the host processing contract and therefore not recorded as a derivative liability. See the following table for a reconciliation of the liability recorded for the embedded derivative as of March 31, 2011 (in thousands).

Fair value of commodity contract	$	108,161
Inception value for period from April 1, 2015 to December 31, 2022		(53,507	)
Derivative liability as of March 31, 2011	$	54,654

        The Partnership has a commodity contract that gives it an option to fix a component of the utilities cost to an index price on electricity at one of its plant locations through the fourth quarter of 2014. The value of the derivative component of this contract is marked to market through Derivative gain related to facility expenses. As of March 31, 2011, the estimated fair value of this contract was an asset of $4.0 million.

Financial Statement Impact of Derivative Instruments

        There were no material changes to the Partnership's policy regarding the accounting for these instruments as previously disclosed in the Partnership's Annual Report on Form 10-K for the year ended December 31, 2010. The impact of the Partnership's derivative instruments on its Condensed Consolidated Balance Sheets is summarized below (in thousands):

		Assets				Liabilities
Derivative instruments not designated as hedging instruments and their balance sheet location		March 31, 2011		December 31, 2010		March 31, 2011			December 31, 2010
Fair value of derivative instruments—current		$	6,138	$	4,345	$	(102,810	)	$	(65,489	)
Fair value of derivative instruments—long-term			3,037		417		(114,211	)		(66,290	)
	Total	$	9,175	$	4,762	$	(217,021	)	$	(131,779	)

12

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

5. Derivative Financial Instruments (Continued)

        The impact of the Partnership's derivative instruments on its Condensed Consolidated Statements of Operations for the three months ended March 31, 2011 and 2010 is summarized below (in thousands):

			Three months ended March 31,
Derivative instruments not designated as hedging instruments and the location of gain or (loss) recognized in income			2011			2010
Revenue: Derivative loss
	Realized loss		$	(14,391	)	$	(13,129	)
	Unrealized (loss) gain			(71,288	)		5,893
		Total revenue: derivative loss		(85,679	)		(7,236	)
Derivative loss related to purchased product costs
	Realized loss			(7,887	)		(5,438	)
	Unrealized loss			(11,507	)		(7,951	)
		Total derivative loss related to purchase product costs		(19,394	)		(13,389	)
Derivative gain related to facility expenses
	Unrealized gain			3,011			806
Derivative gain related to interest expense
	Realized gain			—			2,380
	Unrealized loss			—			(509	)
		Total derivative gain related to interest expense		—			1,871
Miscellaneous (expense) income, net
	Unrealized gain			—			56
		Total loss	$	(102,062	)	$	(17,892	)

        At March 31, 2011, the fair value of the Partnership's commodity derivative contracts is inclusive of premium payments of $3.4 million, net of amortization. For the three months ended March 31, 2011 and 2010, the Realized loss—revenue includes amortization of premium payments of $1.0 million and $0.6 million, respectively.

13

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

6. Fair Value

        Fair value measurements and disclosures relate primarily to the Partnership's derivative positions discussed in Note 5. The following table presents the derivative instruments carried at fair value as of March 31, 2011 and December 31, 2010 (in thousands):

As of March 31, 2011		Assets		Liabilities
Significant other observable inputs (Level 2)
	Commodity contracts	$	492	$	(121,825	)
Significant unobservable inputs (Level 3)
	Commodity contracts		4,636		(40,542	)
	Embedded derivatives in commodity contracts		4,047		(54,654	)
Total carrying value in Condensed Consolidated Balance Sheet		$	9,175	$	(217,021	)

As of December 31, 2010		Assets		Liabilities
Significant other observable inputs (Level 2)
	Commodity derivative contracts	$	52	$	(77,776	)
Significant unobservable inputs (Level 3)
	Commodity derivative contracts		3,674		(18,031	)
	Embedded derivatives in commodity contracts		1,036		(35,972	)
Total carrying value in Condensed Consolidated Balance Sheet		$	4,762	$	(131,779	)

Changes in Level 3 Fair Value Measurements

        The table below includes a rollforward of the balance sheet amounts for the three months ended March 31, 2011 and 2010 for assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy (in thousands).

	Three months ended March 31, 2011
	Commodity Derivative Contracts (net)			Embedded Derivatives in Commodity Contracts (net)
Fair value at beginning of period	$	(14,357	)	$	(34,936	)
Total loss (realized and unrealized) included in earnings(1)		(22,993	)		(19,280	)
Settlements		1,444			3,609
Fair value at end of period	$	(35,906	)	$	(50,607	)
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period(1)	$	(22,779	)	$	(18,692	)

14

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

6. Fair Value (Continued)

	Three months ended March 31, 2010
	Commodity Derivative Contracts (net)			Embedded Derivatives in Commodity Contracts (net)			Interest Rate Contracts			Embedded Derivative in Debt Contract
Fair value at beginning of period	$	(11,340	)	$	(34,199	)	$	509		$	(190	)
Total gain or loss (realized and unrealized) included in earnings(1)		(2,758	)		936			1,871			56
Purchases, sales, issuances and settlements (net)		6,191			2,402			(2,380	)		—
Fair value at end of period	$	(7,907	)	$	(30,861	)	$	—		$	(134	)
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period(1)	$	(3,521	)	$	3,338		$	—		$	56

(1)

Losses on Commodity Derivative Contracts classified as Level 3 are recorded in Derivative loss related to revenue. Gains and losses on Embedded Derivatives in Commodity Contracts are recorded in Purchased product costs, Derivative loss related to purchased product costs and Derivative gain related to facility expenses. Gains on Embedded Derivatives in Debt Contract are recorded in Miscellaneous (expense) income, net. Gains on Interest Rate Contracts are recorded in Derivative gain related to interest expense.

7. Inventories

        Inventories consist of the following (in thousands):

		March 31, 2011		December 31, 2010
Natural gas and natural gas liquids		$	7,383	$	15,930
Spare parts			8,539		7,502
	Total inventories	$	15,922	$	23,432

15

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

8. Goodwill

        Changes in goodwill for the three months ended March 31, 2011 are summarized as follows (in thousands):

	Southwest			Northeast		Gulf Coast			Total
Historical goodwill	$	24,324		$	3,948	$	9,854		$	38,126
Cumulative impairment		(18,851	)		—		(9,854	)		(28,705	)
Balance as of December 31, 2010		5,473			3,948		—			9,421
Acquisition(1)		—			58,497		—			58,497
Balance as of March 31, 2011	$	5,473		$	62,445	$	—		$	67,918

(1)

Represents goodwill associated with the Langley Acquisition (see Note 3).

9. Long-Term Debt

        Debt is summarized below (in thousands):

			March 31, 2011		December 31, 2010
Credit Facility
	Revolving credit facility, 4.29% interest due July 2015		$	139,200	$	—
Senior Notes(1)
	Senior Notes, 8.5% interest, net of discount of $6 and $642, respectively, issued July 2006 and due July 2016			2,784		274,358
	Senior Notes, 8.75% interest, net of discount of $597 and $924, respectively, issued April and May 2008 and due April 2018			333,765		499,076
	Senior Notes, 6.75% interest, issued November 2010 and due November 2020			500,000		500,000
	Senior Notes, 6.5% interest, net of discount of $992, issued February and March 2011 and due August 2021			499,008		—
		Total long-term debt	$	1,474,757	$	1,273,434

(1)

The estimated aggregate fair value of the Senior Notes was approximately $1,382.7 million and $1,333.9 million as of March 31, 2011 and December 31, 2010, respectively, based on quoted market prices.

Credit Facility

        Under the provisions of the Credit Facility, the Partnership is subject to a number of restrictions and covenants. These covenants are used to calculate the available borrowing capacity on a quarterly

16

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

9. Long-Term Debt (Continued)

basis. The Credit Facility is guaranteed by the Partnership's wholly-owned subsidiaries and collateralized by substantially all of the Partnership's assets and those of its wholly-owned subsidiaries. As of March 31, 2011, the Partnership had $139.2 million of borrowings outstanding and $27.4 million of letters of credit outstanding under the Credit Facility, leaving approximately $538.4 million available for borrowing.

Senior Notes

        On February 24, 2011, the Partnership completed a public offering of $300 million in aggregate principal amount of 6.5% senior unsecured notes ("2021 Senior Notes"), which were issued at par. The 2021 Senior Notes mature on August 15, 2021, and interest is payable semi-annually in arrears on February 15 and August 15, commencing August 15, 2011. The Partnership received net proceeds of approximately $296 million after deducting the underwriting fees and other third-party expenses associated with the offering. The Partnership used the net proceeds from this offering to fund the concurrent repurchase of approximately $272.2 million in aggregate principal amount of the Partnership's 2016 Senior Notes, pursuant to the Partnership's tender offer for any and all of the outstanding 2016 Senior Notes, and the remaining proceeds were used to repay borrowings under the Credit Facility. The Partnership recorded a pre-tax loss on redemption of debt of approximately $21.0 million in the first quarter of 2011 related to the 2016 Senior Notes, which consisted of approximately $1.1 million for the non-cash write off of the unamortized discount and deferred finance costs and approximately $19.9 million for the payment of the related tender premiums and third-party expenses.

        On March 10, 2011, the Partnership completed a follow-on public offering of an additional $200 million in aggregate principal amount of 2021 Senior Notes, which were issued at 99.5% of par and are treated as a single class of debt securities under the same indenture as the 2021 Senior Notes issued on February 24, 2011. The Partnership received net proceeds of approximately $196 million after deducting the underwriting fees and other third-party expenses associated with the offering. The Partnership used the net proceeds from this offering to fund the concurrent repurchase of approximately $165.6 million in aggregate principal amount of the Partnership's 2018 Senior Notes pursuant to the Partnership's tender offer for up to $170 million of the outstanding 2018 Senior Notes and the remaining proceeds were used to repay borrowings under the Credit Facility. The Partnership recorded a pre-tax loss on redemption of debt of approximately $22.3 million in the first quarter of 2011 related to the 2018 Senior Notes, which consisted of approximately $2.7 million for the non-cash write off of the unamortized discount and deferred finance costs and approximately $19.6 million for the payment of the related tender premiums and third-party expenses.

10. Equity

Equity Offering

        On January 14, 2011, the Partnership completed a public offering of approximately 3.45 million newly issued common units representing limited partner interests, which includes the full exercise of the underwriters' over-allotment option, at a price of $41.20 per common unit. Net proceeds of approximately $138.2 million were used to partially fund the Partnership's ongoing capital expenditure program, including a portion of the costs associated with the Langley Acquisition (see Note 3).

17

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

10. Equity (Continued)

Distributions of Available Cash

Quarter Ended	Distribution Per Common Unit		Record Date		Payment Date
March 31, 2011	$	0.67		May 2, 2011		May 13, 2011
December 31, 2010	$	0.65		February 7, 2011		February 14, 2011

11. Commitments and Contingencies

Legal

        The Partnership is subject to a variety of risks and disputes, and is a party to various legal proceedings in the normal course of its business. The Partnership maintains insurance policies in amounts and with coverage and deductibles as it believes reasonable and prudent. However, the Partnership cannot assure that the insurance companies will promptly honor their policy obligations or that the coverage or levels of insurance will be adequate to protect the Partnership from all material expenses related to future claims for property loss or business interruption to the Partnership, or for third-party claims of personal and property damage, or that the coverages or levels of insurance it currently has will be available in the future at economical prices. While it is not possible to predict the outcome of the legal actions with certainty, management is of the opinion that appropriate provisions and accruals for potential losses associated with all legal actions have been made in the consolidated financial statements.

        In June 2006, the Pipeline and Hazardous Materials Safety Administration issued a Notice of Probable Violation and Proposed Civil Penalty ("NOPV") (CPF No. 2-2006-5001) to both MarkWest Hydrocarbon and Equitable Production Company ("Equitable"). The NOPV is associated with the pipeline leak and an ensuing explosion and fire that occurred on November 8, 2004 in Ivel, Kentucky on an NGL pipeline owned by Equitable and leased and operated by a subsidiary of the Partnership, MarkWest Energy Appalachia, L.L.C. The NOPV sets forth six counts of violations of applicable regulations, and a proposed civil penalty in the aggregate amount of $1.1 million. In March 2011, MarkWest received an order assessing a penalty solely against Equitable for count one of the NOPV in the amount of $0.5 million and assessing a penalty jointly and severally against MarkWest and Equitable for four of the other counts in the NOPV in the amount of $0.2 million. In March 2011, the parties filed separate petitions for reconsideration, which remain pending.

        In the ordinary course of business, the Partnership is a party to various other legal and regulatory actions. In the opinion of management, none of these actions, either individually or in the aggregate, will have a material adverse effect on the Partnership's financial condition, liquidity or results of operations.

18

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

12. Incentive Compensation Plans

Compensation Expense

        Total compensation expense recorded for share-based pay arrangements for the three months ended March 31, 2011 and 2010 is as follows (in thousands):

	Three months ended March 31,
	2011		2010
Phantom units	$	5,636	$	6,285
Distribution equivalent rights		102		311
Total compensation expense	$	5,738	$	6,596

        As of March 31, 2011, total compensation expense not yet recognized related to the unvested awards under the 2008 LTIP was approximately $19.1 million, with a weighted-average remaining vesting period of approximately 1.5 years.

        As part of a net settlement option, employees may elect to surrender a certain number of phantom units upon vesting, and in exchange, the Partnership will assume the income tax withholding obligations related to the vesting. Other than the amounts paid related to the net settlement option, there were no cash settlements and the Partnership received no proceeds for issuing phantom units during the three months ended March 31, 2011 and 2010.

2008 LTIP and 2006 Hydrocarbon Plan

        The following is a summary of phantom unit activity under the 2008 LTIP and 2006 Hydrocarbon Plan:

		Number of Units			Weighted-average Grant-date Fair Value
Unvested at December 31, 2010			1,329,160		$	24.86
	Granted(1)		302,362			42.59
	Vested(2)		(390,651	)		26.93
	Forfeited(3)		(296,100	)		31.81
Unvested at March 31, 2011(4)			944,771			27.75

(1)

Includes 35,250 phantom units containing performance vesting criteria related to the Partnership's relative total shareholder return ("TSR Performance Units"). In January 2011, based on the Partnership's actual 2010 performance and management's execution of the business plan, the Board exercised its discretion to vest an additional 35,250 TSR Performance Units related to the January 31, 2011 vesting installment.

(2)

Includes 176,250 TSR Performance Units.

(3)

Includes 296,100 phantom units containing performance vesting criteria related to established performance goals determined by the Compensation Committee

19

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

12. Incentive Compensation Plans (Continued)

("Performance Units"). The performance criteria were not achieved and the phantom units were forfeited in January 2011.

(4)

The calculation of the grant-date fair value for unvested units at March 31, 2011 includes the fair value as of March 31, 2011 for 35,250 TSR Performance Units. A grant date, as defined by GAAP, has not been established for these units.

Includes 141,000 TSR Performance Units. Compensation expense recognized related to TSR Performance Units was approximately $2.8 million and zero for the three months ended March 31, 2011 and 2010, respectively.

Includes 141,000 Performance Units that are not expected to vest. Compensation expense recognized for these Performance Units was zero for the three months ended March 31, 2011 and 2010.

	Three months ended March 31,
	2011		2010
	(in thousands)
Total grant-date fair value of phantom units granted during the period(1)	$	12,878	$	7,968
Total fair value of phantom units vested during the period(2)	$	10,521	$	9,505

(1)

The calculation of the grant-date fair value for units granted during the three months ended March 31, 2011 includes the fair value of $1.5 million for 35,250 TSR Performance Units.

(2)

The calculation of the fair value of phantom units vested during the three months ended March 31, 2011 includes the fair value of $4.9 million for 176,250 TSR Performance Units.

2002 LTIP

        The following is a summary of phantom unit activity under the 2002 LTIP:

		Number of Units			Weighted-average Grant-date Fair Value
Unvested at December 31, 2010			23,645		$	33.83
	Vested		(23,645	)		33.83
Unvested at March 31, 2011			—			—

	Three months ended March 31,
	2011		2010
	(in thousands)
Total fair value of phantom units vested during the period	$	1,030	$	1,255

20

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

13. Income Taxes

        A reconciliation of the provision for income tax and the amount computed by applying the federal statutory rate to (loss) income before provision for income tax for the three months ended March 31, 2011 and 2010 is as follows (in thousands):

		Three months ended March 31, 2011
		Corporation			Partnership			Eliminations			Consolidated
Loss before provision for income tax		$	(19,996	)	$	(67,436	)	$	(1,369	)	$	(88,801	)
Federal statutory rate			35	%		0	%		0	%
Federal income tax at statutory rate		$	(6,999	)	$	—		$	—		$	(6,999	)
Permanent items			(77	)		—			—			(77	)
State income taxes net of federal benefit			(682	)		(343	)		—			(1,025	)
Provision on income from Class A units(1)			(6,029	)		—			—			(6,029	)
	Provision for income tax	$	(13,787	)	$	(343	)	$	—		$	(14,130	)

		Three months ended March 31, 2010
		Corporation			Partnership			Eliminations			Consolidated
Income before provision for income tax		$	3,234		$	27,302		$	(106	)	$	30,430
Federal statutory rate			35	%		0	%		0	%
Federal income tax at statutory rate		$	1,132		$	—		$	—		$	1,132
Permanent items			1			—			—			1
State income taxes net of federal benefit			115			155			—			270
Provision on income from Class A units(1)			3,023			—			—			3,023
	Provision for income tax	$	4,271		$	155		$	—		$	4,426

(1)

The Corporation and the General Partner of the Partnership own Class A units of the Partnership that were received in the merger of the Corporation and the Partnership completed in February 2008. For further discussion of Class A units, see Item 1. Business in the Partnership's Annual Report on Form 10-K for the year ended December 31, 2010.

21

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

14. (Loss) Earnings Per Common Unit

        The following table shows the computation of basic and diluted net (loss) income per common unit for the three months ended March 31, 2011 and 2010, and the weighted-average units used to compute diluted net (loss) income per common unit (in thousands, except per unit data):

		Three months ended March 31,
		2011			2010
Net (loss) income attributable to the Partnership		$	(84,029	)	$	21,510
Less: Income allocable to phantom units			420			277
(Loss) income available for common unitholders		$	(84,449	)	$	21,233
Weighted average common units outstanding—basic			74,531			66,453
Weighted average common units outstanding—diluted(1)			74,531			66,453
Net (loss) income attributable to the Partnership's common unitholders per common unit
	Basic	$	(1.13	)	$	0.32
	Diluted	$	(1.13	)	$	0.32

(1)

Dilutive instruments include TSR Performance Units and are based on the number of units, if any, that would be issuable at the end of the respective reporting period, assuming that date was the end of the contingency period. For the three months ended March 31, 2011, 156 units were excluded from the calculation of diluted units because the impact was anti-dilutive.

15. Segment Information

        The Partnership prepares segment information in accordance with GAAP. Certain items below (Loss) income from operations in the accompanying Condensed Consolidated Statements of Operations, certain compensation expense, certain other non-cash items and any gains (losses) from derivative instruments are not allocated to individual segments. Management does not consider these items allocable to or controllable by any individual segment and therefore excludes these items when evaluating segment performance. Segment results are also adjusted to exclude the portion of operating income attributable to the non-controlling interests.

22

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

15. Segment Information (Continued)

        The tables below present the Partnership's segment profit measure, Operating income before items not allocated to segments, and capital expenditures for the reported segments for the three months ended March 31, 2011 and 2010 (in thousands).

Three months ended March 31, 2011:			Southwest		Northeast		Liberty		Gulf Coast		Total
Segment revenue			$	201,774	$	92,091	$	41,219	$	21,759	$	356,843
Purchased product costs				103,196		40,878		9,555		—		153,629
	Net operating margin			98,578		51,213		31,664		21,759		203,214
Facility expenses				20,157		5,594		6,498		8,990		41,239
Portion of operating income attributable to non-controlling interests				1,172		—		12,377		—		13,549
	Operating income before items not allocated to segments		$	77,249	$	45,619	$	12,789	$	12,769	$	148,426
Capital expenditures			$	17,156	$	709	$	94,146	$	294	$	112,305
Capital expenditures not allocated to segments												1,347
		Total capital expenditures									$	113,652

Three months ended March 31, 2010:			Southwest		Northeast		Liberty		Gulf Coast		Total
Segment revenue			$	164,964	$	111,848	$	19,010	$	19,793	$	315,615
Purchased product costs				74,625		67,087		2,584		—		144,296
	Net operating margin			90,339		44,761		16,426		19,793		171,319
Facility expenses				20,489		4,225		7,313		5,695		37,722
Portion of operating income attributable to non-controlling interests				1,500		—		3,637		—		5,137
	Operating income before items not allocated to segments		$	68,350	$	40,536	$	5,476	$	14,098	$	128,460
Capital expenditures			$	40,133	$	591	$	51,217	$	2,865	$	94,806
Capital expenditures not allocated to segments												516
		Total capital expenditures									$	95,322

23

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

15. Segment Information (Continued)

        The following is a reconciliation of segment revenue to total revenue and operating income before items not allocated to segments to (loss) income before provision for income tax for the three months ended March 31, 2011 and 2010 (in thousands).

			Three months ended March 31,
			2011			2010
Total segment revenue			$	356,843		$	315,615
	Derivative loss not allocated to segments			(85,679	)		(7,236	)
	Revenue deferral adjustment(1)			(7,943	)		—
		Total revenue	$	263,221		$	308,379
Operating income before items not allocated to segments			$	148,426		$	128,460
	Portion of operating income attributable to non-controlling interests			13,549			5,137
	Derivative loss not allocated to segments			(102,062	)		(19,819	)
	Revenue deferral adjustment(1)			(7,943	)		—
	Compensation expense included in facility expenses not allocated to segments			(1,040	)		(722	)
	Facility expenses adjustments			2,855			539
	Selling, general and administrative expenses			(21,712	)		(21,508	)
	Depreciation			(34,364	)		(28,187	)
	Amortization of intangible assets			(10,817	)		(10,193	)
	(Loss) gain on disposal of property, plant and equipment			(2,099	)		9
	Accretion of asset retirement obligations			(87	)		(143	)
		(Loss) income from operations		(15,294	)		53,573
	Loss from unconsolidated affiliate			(539	)		(68	)
	Interest income			89			386
	Interest expense			(28,263	)		(23,782	)
	Amortization of deferred financing costs and discount (a component of interest expense)			(1,428	)		(2,612	)
	Derivative gain related to interest expense			—			1,871
	Loss on redemption of debt			(43,328	)		—
	Miscellaneous (expense) income, net			(38	)		1,062
		(Loss) income before provision for income tax	$	(88,801	)	$	30,430

(1)

Amount relates to certain contracts in which the cash consideration that the Partnership receives for providing service is greater during the initial years of the contract compared to the later years. In accordance with GAAP, the revenue must be recognized evenly over the term of the contract as the Partnership will perform a similar level of service for the entire term; therefore, the revenue recognized in the current reporting period is less than the cash received. However, the chief operating decision maker and management evaluate the segment performance based on the cash consideration received and therefore the

24

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

15. Segment Information (Continued)

impact of the revenue deferrals is excluded for segment reporting purposes. For the three months ended March 31, 2011, approximately $6.5 million and $1.4 million of the revenue deferral adjustment is attributable to the Southwest segment and Northeast segment, respectively. Beginning in 2015, the cash consideration received from these contracts will decline and the reported segment revenue will be less than the revenue recognized for GAAP purposes.

        The tables below present information about segment assets as of March 31, 2011 and December 31, 2010 (in thousands):

		March 31, 2011		December 31, 2010
Southwest		$	1,658,012	$	1,646,607
Northeast			456,441		244,219
Liberty			790,441		743,943
Gulf Coast			571,576		573,456
Total segment assets			3,476,470		3,208,225
Assets not allocated to segments:
	Certain cash and cash equivalents		60,220		49,776
	Fair value of derivatives		9,175		4,762
	Investment in unconsolidated affiliate		28,149		28,688
	Other(1)		43,372		41,911
Total assets		$	3,617,386	$	3,333,362

(1)

Includes corporate fixed assets, deferred financing costs, income tax receivable, receivables and other corporate assets not allocated to segments.

25

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information

        The Partnership has no significant operations independent of its subsidiaries. As of March 31, 2011, the Partnership's obligations under the outstanding Senior Notes (see Note 9) were fully and unconditionally guaranteed, jointly and severally, by all of its wholly-owned subsidiaries. MarkWest Liberty Midstream and MarkWest Pioneer, together with certain of the Partnership's other subsidiaries that do not guarantee the outstanding Senior Notes, have significant assets and operations in aggregate. For the purpose of the following financial information, the Partnership's investments in its subsidiaries and the guarantor subsidiaries' investments in their subsidiaries are presented in accordance with the equity method of accounting. The financial information may not necessarily be indicative of results of operations, cash flows, or financial position had the subsidiaries operated as independent entities. The operations, cash flows and financial position of the co-issuer of the Senior Notes, MarkWest Energy Finance Corporation, are minor and therefore have been included with the Parent's financial information. Condensed consolidating financial information for the Partnership, its combined guarantor

26

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

and combined non-guarantor subsidiaries as of March 31, 2011 and December 31, 2010 and for the three months ended March 31, 2011 and 2010 is as follows (in thousands):

Condensed Consolidating Balance Sheets

			As of March 31, 2011
			Parent		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
ASSETS
Current assets:
	Cash and cash equivalents		$	10	$	63,314	$	9,828	$	—		$	73,152
	Receivables and other current assets			1,849		187,087		19,472		—			208,408
	Intercompany receivables			1,662,651		1,283		8,866		(1,672,800	)		—
	Fair value of derivative instruments			—		6,138		—		—			6,138
		Total current assets		1,664,510		257,822		38,166		(1,672,800	)		287,698
Total property, plant and equipment, net				4,272		1,647,446		883,482		(12,848	)		2,522,352
Other long-term assets:
	Restricted cash			—		—		28,052		—			28,052
	Investment in unconsolidated affiliate			—		28,149		—		—			28,149
	Investment in consolidated affiliates			717,586		406,842		—		(1,124,428	)		—
	Intangibles, net of accumulated amortization			—		635,999		569		—			636,568
	Fair value of derivative instruments			—		3,037		—		—			3,037
	Intercompany notes receivable			185,660		—		—		(185,660	)		—
	Deferred income taxes			—		5,425		—		—			5,425
	Other long-term assets			34,836		70,891		378		—			106,105
		Total assets	$	2,606,864	$	3,055,611	$	950,647	$	(2,995,736	)	$	3,617,386
LIABILITIES AND EQUITY
Current liabilities:
	Intercompany payables		$	671	$	1,671,337	$	792	$	(1,672,800	)	$	—
	Fair value of derivative instruments			—		102,810		—		—			102,810
	Other current liabilities			36,751		168,426		59,518		—			264,695
		Total current liabilities		37,422		1,942,573		60,310		(1,672,800	)		367,505
Deferred income taxes				1,666		—		—		—			1,666
Intercompany notes payable				—		171,660		14,000		(185,660	)		—
Fair value of derivative instruments				—		114,211		—		—			114,211
Long-term debt, net of discounts				1,474,757		—		—		—			1,474,757
Other long-term liabilities				3,398		109,581		188		—			113,167
Equity:
	MarkWest Energy Partners, L.P. partners' capital			1,089,621		717,586		876,149		(1,606,583	)		1,076,773
	Non-controlling interest in consolidated subsidiaries			—		—		—		469,307			469,307
		Total equity		1,089,621		717,586		876,149		(1,137,276	)		1,546,080
		Total liabilities and equity	$	2,606,864	$	3,055,611	$	950,647	$	(2,995,736	)	$	3,617,386

27

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

			As of December 31, 2010
			Parent		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
ASSETS
Current assets:
	Cash and cash equivalents		$	—	$	63,850	$	3,600	$	—		$	67,450
	Receivables and other current assets			1,708		172,209		52,834		—			226,751
	Intercompany receivables			1,440,302		1,099		7,635		(1,449,036	)		—
	Fair value of derivative instruments			—		4,345		—		—			4,345
		Total current assets		1,442,010		241,503		64,069		(1,449,036	)		298,546
Total property, plant and equipment, net				4,623		1,512,763		812,898		(11,260	)		2,319,024
Other long-term assets:
	Restricted cash			—		—		28,001		—			28,001
	Investment in unconsolidated affiliate			—		28,688		—		—			28,688
	Investment in consolidated affiliates			716,673		368,864		—		(1,085,537	)		—
	Intangibles, net of accumulated amortization			—		613,000		578		—			613,578
	Fair value of derivative instruments			—		417		—		—			417
	Intercompany notes receivable			197,710		—		—		(197,710	)		—
	Other long-term assets			32,587		12,139		382		—			45,108
		Total assets	$	2,393,603	$	2,777,374	$	905,928	$	(2,743,543	)	$	3,333,362
LIABILITIES AND EQUITY
Current liabilities:
	Intercompany payables		$	672	$	1,447,799	$	565	$	(1,449,036	)	$	—
	Fair value of derivative instruments			—		65,489		—		—			65,489
	Other current liabilities			31,882		173,667		70,804		—			276,353
		Total current liabilities		32,554		1,686,955		71,369		(1,449,036	)		341,842
Deferred income taxes				2,533		7,894		—		—			10,427
Intercompany notes payable				—		197,710		—		(197,710	)		—
Fair value of derivative instruments				—		66,290		—		—			66,290
Long-term debt, net of discounts				1,273,434		—		—		—			1,273,434
Other long-term liabilities				3,319		101,852		178		—			105,349
Equity:
	MarkWest Energy Partners, L.P. partners' capital			1,081,763		716,673		834,381		(1,562,314	)		1,070,503
	Non-controlling interest in consolidated subsidiaries			—		—		—		465,517			465,517
		Total equity		1,081,763		716,673		834,381		(1,096,797	)		1,536,020
		Total liabilities and equity	$	2,393,603	$	2,777,374	$	905,928	$	(2,743,543	)	$	3,333,362

28

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

Condensed Consolidating Statements of Operations

			Three Months Ended March 31, 2011
			Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Total revenue			$	—		$	218,480		$	44,741		$	—		$	263,221
Operating expenses:
	Purchased product costs			—			163,444			9,579			—			173,023
	Facility expenses			—			28,931			7,649			(167	)		36,413
	Selling, general and administrative expenses			12,854			8,218			2,037			(1,397	)		21,712
	Depreciation and amortization			175			36,469			8,685			(148	)		45,181
	Other operating expenses			299			1,839			48			—			2,186
		Total operating expenses		13,328			238,901			27,998			(1,712	)		278,515
		(Loss) income from operations		(13,328	)		(20,421	)		16,743			1,712			(15,294	)
(Loss) earnings from consolidated affiliates				(1,233	)		7,375			—			(6,142	)		—
Loss on redemption of debt				(43,328	)		—			—			—			(43,328	)
Other expense, net				(24,894	)		(1,975	)		(10	)		(3,300	)		(30,179	)
		(Loss) income before provision for income tax		(82,783	)		(15,021	)		16,733			(7,730	)		(88,801	)
Provision for income tax benefit				(342	)		(13,788	)		—			—			(14,130	)
		Net (loss) income		(82,441	)		(1,233	)		16,733			(7,730	)		(74,671	)
Net income attributable to non-controlling interest				—			—			—			(9,358	)		(9,358	)
		Net (loss) income attributable to the Partnership	$	(82,441	)	$	(1,233	)	$	16,733		$	(17,088	)	$	(84,029	)

29

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

			Three Months Ended March 31, 2010
			Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
Total revenue			$	—		$	285,144		$	23,235	$	—		$	308,379
Operating expenses:
	Purchased product costs			—			155,073			2,612		—			157,685
	Facility expenses			—			28,793			8,469		(163	)		37,099
	Selling, general and administrative expenses			11,781			9,635			1,310		(1,218	)		21,508
	Depreciation and amortization			147			32,710			5,597		(74	)		38,380
	Other operating expenses			—			(155	)		289		—			134
		Total operating expenses		11,928			226,056			18,277		(1,455	)		254,806
		(Loss) income from operations		(11,928	)		59,088			4,958		1,455			53,573
Earnings from consolidated affiliates				53,853			829			—		(54,682	)		—
Other (expense) income, net				(19,551	)		(1,793	)		365		(2,164	)		(23,143	)
		Income before provision for income tax		22,374			58,124			5,323		(55,391	)		30,430
Provision for income tax expense				155			4,271			—		—			4,426
		Net income		22,219			53,853			5,323		(55,391	)		26,004
Net income attributable to non-controlling interest				—			—			—		(4,494	)		(4,494	)
		Net income attributable to the Partnership	$	22,219		$	53,853		$	5,323	$	(59,885	)	$	21,510

30

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

Condensed Consolidating Statements of Cash Flows

			Three Months Ended March 31, 2011
			Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash (used in) provided by operating activities			$	(25,444	)	$	83,297		$	59,203		$	(1,737	)	$	115,319
Cash flows from investing activities:
	Capital expenditures			(125	)		(20,629	)		(95,964	)		3,066			(113,652	)
	Acqusitions			—			(230,728	)		—			—			(230,728	)
	Equity investments			(11,496	)		(41,360	)		—			52,856			—
	Distributions from consolidated affiliates			10,446			10,757			—			(21,203	)		—
	Collection of (investment in) intercompany notes, net			12,050			(14,000	)		—			1,950			—
	Proceeds from disposal of property, plant and equipment			—			134			3,954			(1,329	)		2,759
		Net cash provided by (used in) investing activities		10,875			(295,826	)		(92,010	)		35,340			(341,621	)
Cash flows from financing activities:
	Proceeds from revolving credit facility			307,600			—			—			—			307,600
	Payments of revolving credit facility			(168,400	)		—			—			—			(168,400	)
	Proceeds from long-term debt			499,000			—			—			—			499,000
	Payments of long-term debt			(437,848	)		—			—			—			(437,848	)
	Payments of premiums on redemption of long-term debt			(39,520	)		—			—			—			(39,520	)
	(Payments of) proceeds from intercompany notes, net			—			(12,050	)		14,000			(1,950	)		—
	Payments for debt issuance costs, deferred financing costs and registration costs			(6,524	)		—			—			—			(6,524	)
	Contributions from parent, net			—			11,496			—			(11,496	)		—
	Contributions to joint ventures, net			—			—			49,360			(41,360	)		8,000
	Payments of SMR liability			—			(452	)		—			—			(452	)
	Proceeds from public equity offering, net			138,163			—			—			—			138,163
	Share-based payment activity			(6,269	)		1,096			—			—			(5,173	)
	Payment of distributions			(49,274	)		(10,446	)		(24,325	)		21,203			(62,842	)
	Intercompany advances, net			(222,349	)		222,349			—			—			—
		Net cash provided by financing activities		14,579			211,993			39,035			(33,603	)		232,004
Net increase (decrease) in cash				10			(536	)		6,228			—			5,702
Cash and cash equivalents at beginning of year				—			63,850			3,600			—			67,450
Cash and cash equivalents at end of period			$	10		$	63,314		$	9,828		$	—		$	73,152

31

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

16. Supplemental Condensed Consolidating Financial Information (Continued)

			Three Months Ended March 31, 2010
			Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net cash (used in) provided by operating activities			$	(9,729	)	$	112,836		$	12,036		$	(783	)	$	114,360
Cash flows from investing activities:
	Capital expenditures			(53	)		(42,925	)		(53,127	)		783			(95,322	)
	Equity investments			(10,101	)		(34,543	)		—			44,644			—
	Distributions from consolidated affiliates			12,710			1,270			—			(13,980	)		—
	Collection of intercompany notes, net			21,150			—			—			(21,150	)		—
	Proceeds from disposal of property, plant and equipment			—			292			—			—			292
		Net cash provided by (used in) investing activities		23,706			(75,906	)		(53,127	)		10,297			(95,030	)
Cash flows from financing activities:
	Proceeds from revolving credit facility			135,604			—			—			—			135,604
	Payments of revolving credit facility			(141,904	)		—			—			—			(141,904	)
	Payments of intercompany notes, net			—			(21,150	)		—			21,150			—
	Contributions from parent, net			—			10,101			—			(10,101	)		—
	Contributions to joint ventures, net			—			—			76,763			(34,543	)		42,220
	Payments of SMR liability			—			(58	)		—			—			(58	)
	Share-based payment activity			(3,730	)		97			—			—			(3,633	)
	Payment of distributions			(42,866	)		(12,710	)		(2,540	)		13,980			(44,136	)
	Intercompany advances, net			38,919			(38,919	)		—			—			—
		Net cash (used in) provided by financing activities		(13,977	)		(62,639	)		74,223			(9,514	)		(11,907	)
Net (decrease) increase in cash				—			(25,709	)		33,132			—			7,423
Cash and cash equivalents at beginning of year				—			74,448			23,304			—			97,752
Cash and cash equivalents at end of period			$	—		$	48,739		$	56,436		$	—		$	105,175

32

MARKWEST ENERGY PARTNERS, L.P.

Notes to the Condensed Consolidated Financial Statements (Continued)

(unaudited)

17. Supplemental Cash Flow Information

        The following table provides information regarding supplemental cash flow information (in thousands).

	Three months ended March 31,
	2011		2010
Supplemental disclosures of cash flow information:
Cash paid for interest, net of amounts capitalized	$	22,729	$	12,244
Cash paid for income taxes, net of refunds		34		28
Supplemental schedule of non-cash investing and financing activities:
Accrued property, plant and equipment	$	58,218	$	59,861
Interest capitalized on construction in progress		19		2,557
Issuance of common units for vesting of share-based payment awards		5,282		7,030

33

Item 2.    Management's Discussion and Analysis of Financial Condition and Results of Operations

Forward-Looking Statements

        Management's Discussion and Analysis ("MD&A") contains statements that are forward-looking and should be read in conjunction with our condensed consolidated financial statements and accompanying notes included elsewhere in this report and our Annual Report on Form 10-K for the year ended December 31, 2010. Statements that are not historical facts are forward-looking statements. We use words such as "could," "may," "predict," "should," "expect," "hope," "continue," "potential," "plan," "intend," "anticipate," "project," "believe," "estimate," and similar expressions to identify forward-looking statements. These statements are based on current expectations, estimates, assumptions and beliefs concerning future events impacting us and therefore involve a number of risks and uncertainties. Forward-looking statements are not guarantees and actual results could differ materially from those expressed or implied in the forward-looking statements as a result of a number of factors. We do not update publicly any forward-looking statement with new information or future events. Undue reliance should not be placed on forward-looking statements as many of these factors are beyond our ability to control or predict.

Overview

        We are a master limited partnership engaged in the gathering, transportation and processing of natural gas; the transportation, fractionation, marketing and storage of NGLs; and the gathering and transportation of crude oil. We have extensive natural gas gathering, processing and transmission operations in the southwest, Gulf Coast and northeast regions of the United States, including the Marcellus Shale, and are the largest natural gas processor and fractionator in the Appalachian region.

Significant Financial and Other Highlights

        Significant financial and other highlights for the three months ended March 31, 2011 are listed below. Refer to Results of Operations and Liquidity and Capital Resources for further details.

•

Total segment operating income before items not allocated to segments increased approximately $20.0 million, or 16%, for the three months ended March 31, 2011 compared to the same period in 2010. The increase is due primarily to higher commodity prices in 2011, expanding operations in our Liberty and Northeast segments and increased volumes from a large producer in our Southwest segment. The increase was partially offset by a $3.7 million increase in cash paid for the settlement of commodity derivative positions.

•

In January 2011, we received net proceeds of approximately $138.2 million from a public offering of approximately 3.45 million newly issued common units representing limited partner interests, which includes the full exercise of the underwriters' over-allotment option.

•

In February 2011, we completed the Langley Acquisition whereby we acquired gas processing facilities located near Langley, Kentucky, a partially constructed NGL pipeline extending through parts of Kentucky and West Virginia, and certain other related assets, for a cash purchase price of approximately $230.7 million (see Note 3 of the accompanying Notes to the Condensed Consolidated Financial Statements).

•

In February 2011, we completed a public offering of $300.0 million in aggregate principal amount of 2021 Senior Notes. In March 2011, we completed a follow-on offering of an additional $200.0 million in aggregate principal amount of 2021 Senior Notes. We received combined net proceeds of approximately $492 million from the 2021 Senior Notes offerings, which we used primarily to redeem approximately $272.2 million in aggregate principal amount of 8.5% senior notes due 2016 and approximately $165.6 million in aggregate principal amount of 8.75% senior notes due 2018. We recorded a loss on redemption of debt of approximately

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$43.3 million (see Note 9 of the accompanying Notes to the Condensed Consolidated Financial Statements).

Net Operating Margin (a non-GAAP financial measure)

        Management evaluates contract performance on the basis of net operating margin (a non-GAAP financial measure) which is defined as segment revenue, excluding any derivative gain (loss) and adjusted for the non-cash impact of revenue deferrals related to certain agreements, less purchased product costs, excluding any derivative gain (loss). These adjustments have been made for the purpose of enhancing the understanding by both management and investors of the underlying baseline operating performance of our contractual arrangements, which management uses to evaluate our financial performance for purposes of planning and forecasting. Net operating margin does not have any standardized definition and therefore is unlikely to be comparable to similar measures presented by other reporting companies. Net operating margin results should not be evaluated in isolation of, or as a substitute for, our financial results prepared in accordance with GAAP. Our use of net operating margin and the underlying methodology in excluding certain charges is not necessarily an indication of the results of operations expected in the future, or that we will not, in fact, incur such charges in future periods.

        The following is a reconciliation to (Loss) income from operations, the most comparable GAAP financial measure of this non-GAAP financial measure (in thousands):

		Three months ended March 31,
		2011			2010
Segment revenue		$	356,843		$	315,615
Purchased product costs			153,629			144,296
	Net operating margin		203,214			171,319
Facility expenses			39,424			37,905
Derivative loss			102,062			19,819
Revenue deferral adjustment			7,943			—
Selling, general and administrative expenses			21,712			21,508
Depreciation			34,364			28,187
Amortization of intangible assets			10,817			10,193
Loss (gain) on disposal of property, plant and equipment			2,099			(9	)
Accretion of asset retirement obligations			87			143
	(Loss) income from operations	$	(15,294	)	$	53,573

Our Contracts

        We generate the majority of our revenue and net operating margin (a non-GAAP measure, see above for discussion and reconciliation of net operating margin) from natural gas gathering, transportation and processing; NGL transportation, fractionation, marketing and storage; and crude oil gathering and transportation. We enter into a variety of contract types. In many cases, we provide services under contracts that contain a combination of more than one of the following types of arrangements: fee-based, percent-of-proceeds, percent-of-index and keep-whole. See Item 1. Business—Our Contracts in our Annual Report on Form 10-K for the year ended December 31, 2010 for further discussion of each of these types of arrangements.

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        The following table does not give effect to our active commodity risk management program. For the three months ended March 31, 2011, we calculated the following approximate percentages of our segment revenue and net operating margin from the following types of contracts:

	Fee-Based			Percent-of-Proceeds(1)			Percent-of-Index(2)			Keep-Whole(3)			Total
Segment revenue		21	%		34	%		4	%		41	%		100	%
Net operating margin(4)		36	%		27	%		0	%		37	%		100	%

(1)

Includes condensate sales and other types of arrangements tied to NGL prices.

(2)

Includes arrangements tied to natural gas prices.

(3)

Includes condensate sales and other types of arrangements tied to both NGL and natural gas prices.

(4)

We manage our business by taking into account the partial offset of short natural gas positions by long positions primarily in our Southwest segment. The calculated percentages for the net operating margin for percent-of-proceeds, percent-of-index and keep-whole contracts reflect the partial offset of our natural gas positions.

Seasonality

        Our business is affected by seasonal fluctuations in commodity prices. Sales volumes also are affected by various other factors such as fluctuating and seasonal demands for products, changes in transportation and travel patterns and variations in weather patterns from year to year. Our Northeast segment is particularly impacted by seasonality. In our Northeast segment operations, we store a portion of the propane that is produced in the summer to be sold in the winter months. As a result of our seasonality, we generally expect the sales volumes in our Northeast segment to be higher in the first quarter and fourth quarter. These seasonal factors also impact our Liberty segment; however, we anticipate that the expected growth and expansion in our Liberty segment in 2011 will offset this seasonality impact.

Results of Operations

Segment Reporting

        We classify our business in four reportable segments: Southwest, Northeast, Liberty and Gulf Coast. We present information in this MD&A by segment. The segment information appearing in Note 15 of the accompanying Notes to the Condensed Consolidated Financial Statements is presented on a basis consistent with our internal management reporting.

Southwest

•

East Texas.  We own a system that consists of natural gas gathering pipelines, centralized compressor stations, a natural gas processing facility and an NGL pipeline. The East Texas system is located in Panola, Harrison and Rusk Counties and services the Carthage Field. Producing formations in Panola County consist of the Cotton Valley, Pettit, Travis Peak and Haynesville formations. For natural gas that is processed in this area, we purchase the NGLs from the producers under percent-of-proceeds arrangements, or we transport and process volumes for a fee.

•

Oklahoma.  We own a natural gas gathering system in the Woodford Shale play in the Arkoma Basin of southeast Oklahoma. Natural gas gathered in the Woodford system is processed by Centrahoma Processing LLC ("Centrahoma"), our equity investment discussed in Equity Investment in Unconsolidated Affiliate below. In addition, we own the Foss Lake natural gas

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gathering system and the Arapaho I and II natural gas processing plants, all located in Roger Mills, Custer and Ellis Counties of western Oklahoma. The gathering portion consists of a pipeline system that is connected to natural gas wells and associated compression facilities. The majority of the gathered gas ultimately is compressed and delivered to the processing plants. We also own the Grimes gathering system that is located in Roger Mills and Beckham Counties in western Oklahoma and a gathering system in the Granite Wash formation in the Texas panhandle that is connected to our Arapaho processing plants. We plan to complete the Arapaho III natural gas processing plant in the third quarter of 2011, which will increase our processing capacity at the Arapaho complex by 75 MMcf/d to a total of 235 MMcf/d. The gathering and processing expansions are supported by long-term agreements with producer customers.

Through our joint venture MarkWest Pioneer, we operate the Arkoma Connector Pipeline, a 50-mile FERC-regulated pipeline that interconnects with the Midcontinent Express Pipeline and Gulf Crossing Pipeline at Bennington, Oklahoma and is designed to provide approximately 638,000 Dth/d of Woodford Shale takeaway capacity.

•

Other Southwest.  We own a number of natural gas gathering systems located in Texas, Louisiana, Mississippi and New Mexico, including the Appleby gathering system in Nacogdoches County, Texas. We gather a significant portion of the natural gas produced from fields adjacent to our gathering systems, including from wells targeting the Haynesville Shale. In many areas we are the primary gatherer, and in some of the areas served by our smaller systems we are the sole gatherer. In addition, we own four lateral pipelines in Texas and New Mexico. Our Hobbs, New Mexico natural gas pipeline is subject to regulation by FERC.

Northeast

•

Appalachia.  We are the largest processor and fractionator of natural gas in the Appalachian Basin, with fully integrated processing, fractionation, storage and marketing operations. The Appalachian Basin is a large natural gas producing region characterized by long-lived reserves and modest decline rates. Our Appalachian assets include the Kenova, Boldman, Cobb, Kermit and the recently acquired Langley natural gas processing plants, an NGL pipeline and the Siloam NGL fractionation plant. In connection with the Langley Acquisition, we will complete the construction of the Ranger Pipeline to connect the Langley Processing Facilities to our existing NGL pipeline that transports NGLs to our Siloam fractionation facility. We will also install an additional cryogenic natural gas processing plant with a capacity of at least 60 MMcf/d in 2012. In addition, we have two caverns for storing propane and additional propane storage capacity under a long-term firm-capacity agreement with a third party. The Appalachia operations include fractionation and marketing services on behalf of the Liberty segment.

•

Michigan.  We own and operate a FERC-regulated crude oil pipeline in Michigan providing transportation service for three shippers.

Liberty

•

Marcellus Shale.  We operate natural gas gathering systems and processing facilities located primarily in southwestern Pennsylvania and northern West Virginia through MarkWest Liberty Midstream. We are the largest processor of natural gas in the Marcellus Shale, with fully integrated processing, fractionation, storage and marketing operations that are critical to the liquids-rich gas development in the northeast United States. We currently have 355 MMcf/d of cryogenic processing capacity at our Houston, Pennsylvania processing complex, which includes a 200 MMcf/d cryogenic plant that began operations in the second quarter of 2011. We commenced operation of a 135 MMcf/d cryogenic plant at our Majorsville site in the third

37

quarter of 2010 and we expect to increase the cryogenic processing capacity at our Majorsville site to approximately 270 MMcf/d by the third quarter of 2011. We will also construct a 120 MMcf/d cryogenic processing plant in Mobley, West Virginia. The planned and existing capacity discussed above is supported by long-term agreements with our producer customers. We also plan to construct a 200 MMcf/d cryogenic processing plant in northern West Virginia that is also supported by a long-term agreement, the terms of which are subject to confidentiality obligations. Each of the processing plants in the Liberty segment will be connected to the Houston fractionation facilities through new and existing NGL pipelines. In addition, we will also construct an extension of our Majorsville NGL pipeline to receive NGLs produced at a third-party's Fort Beeler processing plant. This will allow certain producers to benefit from our integrated NGL fractionation and marketing system.

We also plan to complete a 60,000 Bbl/d fractionation facility at our Houston complex in 2011. Propane is currently recovered at our Houston processing complex. Further fractionation of the remaining portion of the NGL stream produced at the Liberty processing plants will continue to be performed at the Siloam NGL fractionation plant in our Northeast segment until we have completed construction of our Houston fractionation facility. We also have an interconnect with a key interstate pipeline providing an additional market outlet for the propane produced from this region.

By the end of 2012, MarkWest Liberty Midstream is expected to operate 945 MMcf/d of cryogenic processing capacity serving Marcellus liquids-rich gas producers in southwestern Pennsylvania and northern West Virginia from its Houston, Majorsville, and recently announced Mobley processing complexes.

We are jointly developing two projects with Sunoco Logistics, L.P. ("Sunoco") to provide Marcellus producers with access to multiple ethane markets to serve the growing liquids-rich gas production in the Marcellus. For both projects, Project Mariner and Mariner West, MarkWest Liberty Midstream will make minor modifications to its natural gas processing complexes, will install ethane extraction facilities at its Houston complex, and will construct pipelines from the Houston complex to interconnections with existing Sunoco pipelines. Project Mariner is a pipeline and marine project to deliver purity ethane produced in the Marcellus to Gulf Coast and international markets. Project Mariner is anticipated to have initial capacity to transport up to 50,000 Bbl/d of ethane by mid-2013. Mariner West, which was announced during the first quarter of 2011, is a joint pipeline project to deliver Marcellus ethane to Sarnia, Ontario, Canada markets. Mariner West, which is being developed at the request of Marcellus producer customers and is supported by Sarnia ethane consumers, will utilize new and existing pipelines and is anticipated to have a maximum capacity to transport up to 65,000 Bbl/d of ethane by the third quarter of 2012.

Gulf Coast

•

Javelina.  We own and operate the Javelina processing facility, a natural gas processing facility in Corpus Christi, Texas that treats and processes off-gas from six local refineries operated by three different refinery customers. We have a product supply agreement creating a long-term contractual obligation for the payment of processing fees in exchange for all of the product processed by the SMR that is operated by a third party. The product received under this agreement will be sold to a refinery customer pursuant to a corresponding long-term agreement.

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        The following summarizes the percentage of our segment revenue and net operating margin (a non-GAAP financial measure, see above) generated by our assets, by segment, for the three months ended March 31, 2011:

	Southwest			Northeast			Liberty			Gulf Coast			Total
Segment revenue		56	%		26	%		12	%		6	%		100	%
Net operating margin		48	%		25	%		16	%		11	%		100	%

Equity Investment in Unconsolidated Affiliate

        We own a 40% non-operating membership interest in Centrahoma, a joint venture with Cardinal Midstream, LLC that is accounted for using the equity method. Centrahoma owns certain processing plants in the Arkoma Basin. We have signed long-term agreements to dedicate the processing rights for our natural gas gathering system in the Woodford Shale to Centrahoma. The financial results for Centrahoma are included in Loss from unconsolidated affiliate and are not included in our segment results.

Three months ended March 31, 2011 compared to three months ended March 31, 2010

        Items below (Loss) income from operations in our Condensed Consolidated Statements of Operations, certain compensation expense, certain other non-cash items and any gains (losses) from derivative instruments are not allocated to individual business segments. Management does not consider these items allocable to or controllable by any individual business segment and therefore excludes these items when evaluating segment performance. The segment results are also adjusted to exclude the portion of operating income attributable to the non-controlling interests. The tables below present financial information, as evaluated by management, for the reported segments for the three months ended March 31, 2011 and 2010. The information includes net operating margin, a non-GAAP financial measure. See above for a reconciliation of net operating margin to (Loss) income from operations, the most comparable GAAP financial measure.

Southwest

		Three months ended March 31,
		2011		2010		$ Change			% Change
		(in thousands)
Segment revenue		$	201,774	$	164,964	$	36,810			22	%
Purchased product costs			103,196		74,625		28,571			38	%
	Net operating margin		98,578		90,339		8,239			9	%
Facility expenses			20,157		20,489		(332	)		(2	)%
Portion of operating income attributable to non-controlling interests			1,172		1,500		(328	)		(22	)%
Operating income before items not allocated to segments		$	77,249	$	68,350	$	8,899			13	%

        Segment Revenue.    Revenue increased primarily due to higher commodity prices and an increase in NGL production volumes in Western Oklahoma and our Woodford system. Revenue from NGL, natural gas and condensate sales increased approximately $35.7 million across the segment.

        Purchased Product Costs.    Purchased product costs increased primarily due to higher commodity prices and increased volumes in Western Oklahoma and our Woodford system.

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        Portion of Operating Income Attributable to Non-controlling Interests.    Portion of operating income attributable to non-controlling interests primarily represents our partners' share in net operating income of MarkWest Pioneer.

Northeast

		Three months ended March 31,
		2011		2010		$ Change			% Change
		(in thousands)
Segment revenue		$	92,091	$	111,848	$	(19,757	)		(18	)%
Purchased product costs			40,878		67,087		(26,209	)		(39	)%
	Net operating margin		51,213		44,761		6,452			14	%
Facility expenses			5,594		4,225		1,369			32	%
Operating income before items not allocated to segments		$	45,619	$	40,536	$	5,083			13	%

        Segment Revenue.    Revenue decreased primarily due to a contract change related to the Langley Acquisition. Subsequent to the Langley Acquisition, we are acting as an agent and marketing the NGLs on behalf of our producer customer. Revenue also decreased due to a decrease in volumes processed under keep-whole terms primarily due to the required repairs of a significant transmission pipeline feeding our Kenova plant. The transmission pipeline is scheduled to be repaired in mid-2011 after which we expect volumes to return to normal levels.

        Purchased Product Costs.    Purchased product costs decreased due to the contract change related to the Langley Acquisition discussed in the Segment Revenue section above. In addition, purchased product costs decreased as a percentage of revenue due to an increase in the spread between NGL and natural gas prices.

        Facility Expenses.    Facility expenses increased primarily due to the Langley Acquisition on February 1, 2011 and increased labor and benefits expense.

Liberty

		Three months ended March 31,
		2011		2010		$ Change			% Change
		(in thousands)
Segment revenue		$	41,219	$	19,010	$	22,209			117	%
Purchased product costs			9,555		2,584		6,971			270	%
	Net operating margin		31,664		16,426		15,238			93	%
Facility expenses			6,498		7,313		(815	)		(11	)%
Portion of operating income attributable to non-controlling interests			12,377		3,637		8,740			240	%
Operating income before items not allocated to segments		$	12,789	$	5,476	$	7,313			134	%

        Segment revenue.    Revenue increased due to ongoing expansion of the Liberty operations and higher NGL prices. Revenue increased approximately $11.0 million related to gathering and processing fees and approximately $11.2 million related to NGL product sales.

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        Purchased Product Costs.    Purchased product costs increased primarily due to the purchase of product from certain producers, which began in the second half of 2010. Purchased product costs also increased due to higher prices.

        Facility Expenses.    Facility expenses decreased primarily due to environmental and remediation costs incurred in 2010, which did not recur in 2011, and a reduction in compressor rental expense as compressors were purchased in the second half of 2010. These decreases were partially offset by the ongoing expansion of the Liberty operations.

        Portion of Operating Income Attributable to Non-controlling Interests.    Portion of operating income attributable to non-controlling interests represents M&R's interest in net operating income of MarkWest Liberty Midstream. The increase is the result of ongoing expansion of the Liberty operations, as well as M&R's interest increasing from 40% to 49% effective January 1, 2011.

Gulf Coast

		Three months ended March 31,
		2011		2010		$ Change			% Change
		(in thousands)
Segment revenue		$	21,759	$	19,793	$	1,966			10	%
Purchased product costs			—		—		—			N/A
	Net operating margin		21,759		19,793		1,966			10	%
	Facility expenses		8,990		5,695		3,295			58	%
Operating income before items not allocated to segments		$	12,769	$	14,098	$	(1,329	)		(9	)%

        Segment revenue.    Revenue increased primarily due to the operation of the SMR, which was partially offset by a decrease in volumes.

        Facility Expenses.    Facility expenses increased primarily due to the operating expenses of the SMR, which was partially offset by a decrease in repairs and maintenance and utilities expense.

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Reconciliation of Segment Operating Income to Consolidated (Loss) Income Before Provision for Income Tax

        The following table provides a reconciliation of segment revenue to total revenue and operating income before items not allocated to segments to our consolidated (loss) income before provision for income tax for the three months ended March 31, 2011 and 2010. The ensuing items listed below the Total segment revenue and Operating income lines are not allocated to business segments as management does not consider these items allocable to any individual segment.

			Three months ended March 31,
			2011			2010			$ Change			% Change
			(in thousands)
Total segment revenue			$	356,843		$	315,615		$	41,228			13	%
	Derivative loss not allocated to segments			(85,679	)		(7,236	)		(78,443	)		1,084	%
	Revenue deferral adjustment			(7,943	)		—			(7,943	)		N/A
		Total revenue	$	263,221		$	308,379		$	(45,158	)		(15	)%
Operating income before items not allocated to segments			$	148,426		$	128,460		$	19,966			16	%
	Portion of operating income attributable to non-controlling interests			13,549			5,137			8,412			164	%
	Derivative loss not allocated to segments			(102,062	)		(19,819	)		(82,243	)		415	%
	Revenue deferral adjustment			(7,943	)		—			(7,943	)		N/A
	Compensation expense included in facility expenses not allocated to segments			(1,040	)		(722	)		(318	)		44	%
	Facility expenses adjustments			2,855			539			2,316			430	%
	Selling, general and administrative expenses			(21,712	)		(21,508	)		(204	)		1	%
	Depreciation			(34,364	)		(28,187	)		(6,177	)		22	%
	Amortization of intangible assets			(10,817	)		(10,193	)		(624	)		6	%
	(Loss) gain on disposal of property, plant and equipment			(2,099	)		9			(2,108	)		(23,422	)%
	Accretion of asset retirement obligations			(87	)		(143	)		56			(39	)%
		(Loss) income from operations		(15,294	)		53,573			(68,867	)		(129	)%
	Loss from unconsolidated affiliate			(539	)		(68	)		(471	)		693	%
	Interest income			89			386			(297	)		(77	)%
	Interest expense			(28,263	)		(23,782	)		(4,481	)		19	%
	Amortization of deferred financing costs and discount (a component of interest expense)			(1,428	)		(2,612	)		1,184			(45	)%
	Derivative gain related to interest expense			—			1,871			(1,871	)		(100	)%
	Loss on redemption of debt			(43,328	)		—			(43,328	)		N/A
	Miscellaneous (expense) income, net			(38	)		1,062			(1,100	)		(104	)%
		(Loss) income before provision for income tax	$	(88,801	)	$	30,430		$	(119,231	)		(392	)%

        Derivative Loss Not Allocated to Segments.    Unrealized loss from the mark-to-market of our derivative instruments was $79.8 million in 2011 compared to $1.3 million in 2010. Realized loss from the settlement of our derivative instruments was $22.3 million in 2011 compared to $18.6 million in 2010. The total change of $82.2 million is due mainly to volatility in commodity prices.

        Revenue Deferral Adjustment.    Revenue deferral adjustment relates primarily to certain contracts in which the cash consideration we receive for providing service is greater during the initial years of the contract compared to the later years. In accordance with GAAP, the revenue must be recognized evenly

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over the term of the contract as we will perform a similar level of service for the entire term; therefore, the revenue recognized in the current reporting period is less than the cash received. However, the chief operating decision maker and management evaluate the segment performance based on the cash consideration received and therefore the impact of the revenue deferrals is excluded for segment reporting purposes. For the three months ended March 31, 2011, approximately $6.5 million and $1.4 million of the revenue deferral adjustment is attributable to the Southwest segment and Northeast segment, respectively. Beginning in 2015, the cash consideration received from these contracts will decline and the reported segment revenue will be less than the revenue recognized for GAAP purposes.

        Facility Expenses Adjustments.    Facility expenses adjustments consist of the reallocation of the MarkWest Pioneer field services fee and the reallocation of the interest expense related to the SMR, which is included in facility expenses for the purposes of evaluating the performance of the Gulf Coast segment.

        Depreciation.    Depreciation increased due to additional projects completed during 2010 and the first quarter of 2011, as well as the Langley Acquisition.

        Interest Expense.    Interest expense increased primarily due to additional borrowings in 2010 and 2011 to fund our capital plan, including a net increase in our borrowings resulting from our Senior Notes offerings and related redemptions. Interest expense also increased approximately $1.9 million related to the SMR.

        Amortization of Deferred Financing Costs and Discount.    Amortization of deferred financing costs and discount decreased primarily due to the write off of the unamortized discount associated with our 2014 Senior Notes, which were redeemed in the fourth quarter of 2010.

        Derivative Gain Related to Interest Expense.    Derivative gain related to interest expense decreased due to the settlement of all the outstanding interest rate swaps in January 2010.

        Loss on Redemption of Debt.    Loss on redemption of debt relates to the redemption of $272.2 million of our 2016 Senior Notes and $165.6 million of our 2018 Senior Notes in the first quarter of 2011. Approximately $3.8 million relates to the non-cash write off of the unamortized discount and deferred finance costs and approximately $39.5 million relates to the payment of the related tender premiums and third-party expenses. See Note 9 of the accompanying Notes to the Condensed Consolidated Financial Statements.

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Operating Data

			Three months ended March 31,
			2011		2010		% Change
Southwest
	East Texas
		Gathering systems throughput (Mcf/d)		425,800		429,000		(1	)%
		NGL product sales (gallons)		56,681,300		64,195,800		(12	)%
	Oklahoma
		Foss Lake gathering system throughput (Mcf/d)		67,800		76,000		(11	)%
		Stiles Ranch gathering system throughput (Mcf/d)		132,600		115,800		15	%
		Grimes gathering system throughput (Mcf/d)		7,000		7,900		(11	)%
		Arapaho NGL product sales (gallons)		39,020,100		29,443,300		33	%
		Southeast Oklahoma gathering system throughput (Mcf/d)		498,000		496,600		0	%
		Arkoma Connector Pipeline throughput (Mcf/d)		285,900		357,800		(20	)%
	Other Southwest
		Appleby gathering system throughput (Mcf/d)		26,400		34,600		(24	)%
		Other gathering systems throughput (Mcf/d)(1)		6,700		9,000		(26	)%
Northeast
	Appalachia
		Natural gas processed (Mcf/d)(2)		304,800		193,000		58	%
		Keep-whole sales (gallons)		39,835,800		45,772,400		(13	)%
		Percent-of-proceeds sales (gallons)		30,895,500		27,005,000		14	%
		Total NGL product sales (gallons)(3)		70,731,300		72,777,400		(3	)%
	Michigan
		Crude oil transported for a fee (Bbl/d)		10,200		12,900		(21	)%
Liberty
	Marcellus Shale
		Natural gas processed (Mcf/d)		254,500		93,800		171	%
		Gathering system throughput (Mcf/d)		195,900		100,900		94	%
		NGL product sales (gallons)		51,761,600		21,530,200		140	%
Gulf Coast
		Refinery off-gas processed (Mcf/d)		102,800		113,300		(9	)%
		Liquids fractionated (Bbl/d)		19,200		22,500		(15	)%

(1)

Excludes lateral pipelines where revenue is not based on throughput.

(2)

Includes throughput from the Kenova, Cobb, Boldman and Langley processing plants. We acquired the Langley processing plant in February 2011. The volumes reported are the average daily rates for the days of operation.

(3)

Represents sales at the Siloam fractionator. The total sales exclude 20,654,100 gallons and 10,657,200 gallons sold by the Northeast on behalf of Liberty for the three months ended March 31, 2011 and 2010, respectively.

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Liquidity and Capital Resources

        Our primary strategy is to expand our asset base through organic growth projects and selective third-party acquisitions that are accretive to our cash available for distribution per common unit. In 2010, we spent approximately $458.7 million on organic expansion opportunities, of which a portion was funded by our MarkWest Liberty Midstream joint venture partner.

        Our 2011 capital plan is summarized in the table below (in millions):

		Range
		Low			High
Consolidated growth capital		$	600		$	670
Liberty joint venture partner's estimated share of growth capital			(180	)		(200	)
	Partnership share of growth capital		420			470
Langley Acquisition			230			230
	Partnership share of growth capital and acquisitions	$	650		$	700
Consolidated maintenance capital		$	10		$	20

        As of March 31, 2011 we have spent approximately $113.7 million of consolidated capital, which includes approximately $35.2 million funded by our Liberty joint venture partner through its current period contributions, remaining balances from prior period contributions, and its share of the cash generated from MarkWest Liberty Midstream's operations. We have also spent $230.7 million for the Langley Acquisition.

        Growth capital includes expenditures made to expand the existing operating capacity, to increase the efficiency of our existing assets, and to facilitate an increase in volumes within our operations. Growth capital also includes costs associated with new well connections. Growth capital excludes expenditures for third-party acquisitions and equity investments. Maintenance capital includes capital expenditures made to maintain our operating capacity and asset base.

        Our primary sources of liquidity to meet operating expenses, pay distributions to our unitholders and fund capital expenditures are cash flows generated by our operations, our Credit Facility and access to debt and equity markets, both public and private. We will also consider the use of alternative financing strategies such as entering into additional joint venture arrangements and the sale of non-strategic assets.

        Management believes that expenditures for our current capital projects will be funded with cash flows from operations, current cash balances, contributions by our joint venture partner for capital projects encompassed by the Liberty joint venture, and our current borrowing capacity under the Credit Facility. However, it may be necessary to raise additional funds to finance our future capital requirements. Our access to capital markets can be impacted by factors outside our control, including economic conditions; however, we believe that our strong cash flows and balance sheet, our Credit Facility and our credit rating will provide us with adequate access to funding given our expected cash needs. Any new borrowing cost would be affected by market conditions and long-term debt ratings assigned by independent rating agencies. As of May 2, 2011, our credit ratings were Ba3 with a Stable outlook by Moody's Investors Service, BB- with a Stable outlook by Standard & Poor's and BB with a Stable outlook by Fitch Ratings. Changes in our operating results, cash flows or financial position could impact the ratings assigned by the various rating agencies. Should our credit ratings be adjusted downward, we may incur higher costs to borrow, which could have a material impact on our financial condition and results of operations.

45

Debt Financing Activities

        Our Credit Facility, which matures on July 1, 2015, has a borrowing capacity of $705 million with an accordion feature of up to $195 million of uncommitted funds. Under the provisions of the Credit Facility we are subject to a number of restrictions and covenants. As of March 31, 2011, we were in compliance with all of our debt covenants and we expect to remain in compliance for at least the next twelve months. These covenants are used to calculate the available borrowing capacity on a quarterly basis. As of May 2, 2011, we had $113.3 million of borrowings outstanding and $27.3 million of letters of credit outstanding under the Credit Facility, leaving approximately $564.4 million available for borrowing.

        On February 24, 2011, we completed a public offering of $300 million in aggregate principal amount of 6.5% senior unsecured notes due 2021. Net proceeds of approximately $296 million were used to fund the concurrent repurchase of approximately $272.2 million in aggregate principal amount of our 2016 Senior Notes. On March 10, 2011, we completed a follow-on public offering of an additional $200 million in aggregate principal amount of 6.5% senior unsecured notes due 2021. Net proceeds of approximately $196 million were used to fund the concurrent repurchase of approximately $165.6 million in aggregate principal amount of our 2018 Senior Notes. The remaining proceeds for each of the Senior Notes offerings were used to repay borrowings under our Credit Facility. The Senior Notes issued on February 24, 2011 and March 10, 2011 are treated as a single class of debt securities under the same indenture. As a result of these refinancing activities, we have significantly reduced the interest rates and extended the terms of our long-term financing.

        As of March 31, 2011, we had four series of Senior Notes outstanding: $500.0 million aggregate principal issued in February and March 2011 and due August 2021; $500.0 million aggregate principal issued in November 2010 and due November 2020; $334.4 million aggregate principal issued in April and May 2008 and due April 2018; and $2.8 million aggregate principal issued in July 2006 and due July 2016. For further discussion of the Senior Notes see Note 9 of the accompanying Notes to the Condensed Consolidated Financial Statements.

        The Credit Facility and indentures governing the Senior Notes limit the activity of the Partnership and its restricted subsidiaries. The Credit Facility and indentures place limits on the ability of the Partnership and its restricted subsidiaries to incur additional indebtedness; declare or pay dividends or distributions or redeem, repurchase or retire equity interests or subordinated indebtedness; make investments; incur liens; create any consensual limitation on the ability of the Partnership's restricted subsidiaries to pay dividends or distributions, make loans or transfer property to the Partnership; engage in transactions with the Partnership's affiliates; sell assets, including equity interests of the Partnership's subsidiaries; make any payment on or with respect to, or purchase, redeem, defease or otherwise acquire or retire for value any subordinated obligation or guarantor subordination obligation (except principal and interest at maturity); and consolidate, merge or transfer assets.

        The Credit Facility also limits our ability to enter into transactions with parties that require margin calls under certain derivative instruments. The Credit Facility prevents members of the participating bank group from requiring margin calls. As of May 2, 2011, all of our derivative positions, measured volumetrically, are with members of the participating bank group and are not subject to margin deposit requirements. We believe this arrangement gives us additional liquidity as it allows us to enter into derivative instruments without utilizing cash for margin calls or requiring the use of letters of credit.

Equity Offering

        On January 14, 2011, we completed a public offering of approximately 3.45 million newly issued common units representing limited partner interests, which includes the full exercise of the underwriters' over-allotment option, at a price of $41.20 per common unit. Net proceeds of

46

approximately $138.2 million were used to partially fund our ongoing capital expenditure program, including a portion of the costs associated with the Langley Acquisition.

Cash Flow

        The following table summarizes cash inflows (outflows) (in thousands):

	Three months ended March 31,
	2011			2010			Change
Net cash provided by operating activities	$	115,319		$	114,360		$	959
Net cash used in investing activities		(341,621	)		(95,030	)		(246,591	)
Net cash provided by (used in) financing activities		232,004			(11,907	)		243,911

        Net cash provided by operating activities increased primarily due to a $20.0 million increase in operating income, excluding derivative gains and losses, in our operating segments, which was partially offset by a $3.7 million increase in net cash payments related to the settlement of commodity derivative positions. The increase in operating income was also partially offset by a decrease in operating cash flow resulting from changes in working capital.

        Net cash used in investing activities increased primarily due to the $230.7 million Langley Acquisition and a $42.9 million increase in capital expenditures in the Liberty segment, partially offset by a $23.0 million decrease in capital expenditures in the Southwest segment.

        Net cash provided by (used in) financing activities increased primarily due to:

•

$206.7 million increase in net borrowings, and

•

$138.2 million increase in proceeds from a public equity offering.

        These increases were partially offset by:

•

$39.5 million increase in premiums paid for the redemption of our 2016 and 2018 Senior Notes,

•

$34.2 million decrease in cash contributions received from our joint venture partner,

•

$18.7 million increase in distributions, and

•

$6.5 million increase in payments for debt issuance costs, deferred financing costs and registration costs.

Contractual Obligations

        We periodically make other commitments and become subject to other contractual obligations that we believe to be routine in nature and incidental to the operation of the business. Management believes that such routine commitments and contractual obligations do not have a material impact on our business, financial condition or results of operations. As of March 31, 2011, our purchase obligations for the remainder of 2011 were $112.8 million compared to our 2011 obligations of $56.0 million as of December 31, 2010. The increase is due to obligations related to the ongoing expansion in our Liberty segment. Purchase obligations represent purchase orders and contracts related to property, plant and equipment.

47

Critical Accounting Policies

        The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

        Estimates are used in accounting for, among other items, valuing identified intangible assets; evaluating impairments of long-lived assets, goodwill and equity investments; share-based compensation; risk management activities and derivative financial instruments; and variable interest entities.

        There have not been any material changes during the three months ended March 31, 2011 to the methodology applied by management for critical accounting policies previously disclosed in Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies in our Annual Report on Form 10-K for the year ended December 31, 2010, except as noted below.

Description	Judgments and Uncertainties	Effect if Actual Results Differ from Estimates and Assumptions
Acquisitions—Purchase Price Allocation
We allocate the purchase price of an acquired business to its identifiable assets and liabilities based on estimated fair values. The excess of the purchase price over the amount allocated to the assets and liabilities is recorded as goodwill. For significant acquisitions, we engage outside appraisal firms to assist in the fair value determination of identifiable intangible assets such as agent networks, customer relationships, trade names and any other significant assets or liabilities. We adjust the preliminary purchase price allocation, as necessary, after the acquisition closing date through the end of the measurement period of one year or less as we finalize valuations for the assets acquired and liabilities assumed.	Purchase price allocation methodology requires management to make assumptions and apply judgment to estimate the fair value of acquired assets and liabilities. Management estimates the fair value of assets and liabilities primarily using a market approach, income approach, or replacement cost analysis, as appropriate. Key inputs into the fair value determinations include estimates and assumptions related to future volumes, commodity prices, operating costs and construction costs, as well as an estimate of the expected term of the related customer contract or contracts.	If estimates or assumptions used to complete the purchase price allocation and estimate the fair value of acquired assets and liabilities significantly differed from assumptions made, the allocation of purchase price between goodwill, intangibles, and property plant and equipment could significantly differ. Such a difference would impact future earnings through depreciation and amortization expense. In addition, if forecasts supporting the valuation of the intangibles or goodwill are not achieved, impairments could arise.

Recent Accounting Pronouncements

        Refer to Note 2 of the accompanying Notes to the Condensed Consolidated Financial Statements for information regarding recent accounting pronouncements.

Item 3.    Quantitative and Qualitative Disclosures about Market Risk

        Market risk includes the risk of loss arising from adverse changes in market rates and prices. We face market risk from commodity price changes and, to a lesser extent, interest rate changes and nonperformance by our customers and counterparties.

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Commodity Price Risk

        The information about commodity price risk for the three months ended March 31, 2011 does not differ materially from that discussed in Item 7A. Quantitative and Qualitative Disclosures about Market Risk of our Annual Report on Form 10-K for the year ended December 31, 2010.

Outstanding Derivative Contracts

        The following tables provide information on the volume of our derivative activity for positions related to long liquids and keep-whole price risk at March 31, 2011, including the weighted average prices ("WAVG"):

WTI Crude Collars	Volumes (Bbl/d)		WAVG Floor (Per Bbl)		WAVG Cap (Per Bbl)		Fair Value (in thousands)
2011		1,660	$	67.57	$	85.26	$	(10,532	)
2012		2,634		75.65		97.22		(14,090	)
2013		2,984		85.78		105.24		(6,826	)

WTI Crude Puts	Volumes (Bbl/d)		WAVG Floor (Per Bbl)		Fair Value (in thousands)
2011		1,820	$	80.00	$	406

WTI Crude Swaps	Volumes (Bbl/d)		WAVG Price (Per Bbl)		Fair Value (in thousands)
2011		3,801	$	83.90	$	(24,402	)
2012		4,813		84.54		(37,054	)
2013		1,510		83.86		(10,239	)

Natural Gas Swaps	Volumes (MMBtu/d)		WAVG Price (Per MMBtu)		Fair Value (in thousands)
2011		1,157	$	5.37	$	(322	)
2012		4,650		5.62		(1,438	)
2013		980		5.13		(18	)

        The following tables provide information on the volume of our taxable subsidiary's commodity derivative activity for positions related to keep-whole price risk at March 31, 2011, including the WAVG:

WTI Crude Collars	Volumes (Bbl/d)		WAVG Floor (Per Bbl)		WAVG Cap (Per Bbl)		Fair Value (in thousands)
2012		1,122	$	78.49	$	101.71	$	(4,867	)

WTI Crude Swaps	Volumes (Bbl/d)		WAVG Price (Per Bbl)		Fair Value (in thousands)
2011		2,308	$	90.22	$	(10,978	)
2012		1,840		86.93		(12,699	)
2013		1,304		94.32		(4,111	)

Natural Gas Swaps	Volumes (MMBtu/d)		WAVG Price (Per MMBtu)		Fair Value (in thousands)
2011		16,259	$	7.66	$	(15,860	)
2012		14,419		6.02		(4,495	)
2013		6,582		5.33		286

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        The following table provides information on the derivative positions related to long liquids and keep-whole price risk that we have entered into subsequent to March 31, 2011, including the WAVG:

WTI Crude Collars	Volumes (Bbl/d)		WAVG Floor (Per Bbl)		WAVG Cap (Per Bbl)
2013		730	$	97.50	$	116.48
2014		734		95.36		114.81

        The following tables provide information on the derivative positions of our taxable subsidiary related to keep-whole price risk that we have entered into subsequent to March 31, 2011, including the WAVG:

Natural Gas Swaps	Volumes (MMBtu/d)		WAVG Price (Per MMBtu)
2013		3,211	$	5.36
2014		4,249		5.69

Propane Swaps	Volumes (Gal/d)		WAVG Price (Per Gal)
2013 (Jan-Mar, Oct-Dec)		36,885	$	1.29
2014 (Jan-Mar, Oct-Dec)		87,837		1.25

IsoButane Swaps	Volumes (Gal/d)		WAVG Price (Per Gal)
2013		3,081	$	1.70
2014		3,885		1.67

Normal Butane Swaps	Volumes (Gal/d)		WAVG Price (Per Gal)
2013		8,512	$	1.61
2014		10,711		1.61

Natural Gasoline Swaps	Volumes (Gal/d)		WAVG Price (Per Gal)
2013		5,600	$	2.26
2014		7,106		2.32

Embedded Derivatives in Commodity Contracts

        We have a commodity contract with a producer in the Appalachia region that creates a floor on the frac spread for gas purchases of 9,000 Dth/d. The commodity contract is a component of a broader regional arrangement that also includes a keep-whole processing agreement. This contract is accounted for as an embedded derivative and is recorded at fair value. The changes in fair value of this commodity contract are based on the difference between the contractual and index pricing and are recorded in earnings through Derivative loss related to purchased product costs. In February 2011, we executed agreements with the producer to extend the commodity contract and the related processing agreement from March 31, 2015 to December 31, 2022. As of March 31, 2011, the estimated fair value of this contract was a liability of $108.2 million and the recorded value was $54.7 million. The recorded liability does not include the fair value of the commodity contract related to the extended period from April 1, 2015 to December 31, 2022. In accordance with GAAP for non-option embedded derivatives, the fair value of this extended portion of the commodity contract at its inception of February 1, 2011 is deemed to be allocable to the host processing contract and therefore not recorded as a derivative

50

liability. See the following table for a reconciliation of the liability recorded for the embedded derivative as of March 31, 2011 (in thousands).

Fair value of commodity contract	$	108,161
Inception value for period from April 1, 2015 to December 31, 2022		(53,507	)
Derivative liability as of March 31, 2011	$	54,654

        We have a commodity contract that gives us an option to fix a component of the utilities cost to an index price on electricity at one of our plant locations through the fourth quarter of 2014. The value of the derivative component of this contract is marked to market through Derivative gain related to facility expenses. As of March 31, 2011, the estimated fair value of this contract was an asset of $4.0 million.

Interest Rate Risk

        The information about interest rate risk for the three months ended March 31, 2011 does not differ materially from that discussed in Item 7A. Quantitative and Qualitative Disclosures about Market Risk of our Annual Report on Form 10-K for the year ended December 31, 2010.

Credit Risk

        The information about credit risk for the three months ended March 31, 2011 does not differ materially from that discussed in Item 7A. Quantitative and Qualitative Disclosures about Market Risk of our Annual Report on Form 10-K for the year ended December 31, 2010.

Item 4.    Controls and Procedures

Evaluation of Disclosure Controls and Procedures

        An evaluation was performed under the supervision and with the participation of the Partnership's management, including the Chief Executive Officer and Chief Financial Officer, of the effectiveness of the design and operation of our disclosure controls and procedures, as defined in Rule 13a-15(e) of the 1934 Act, as of March 31, 2011. Based on this evaluation, the Partnership's management, including our Chief Executive Officer and Chief Financial Officer, concluded that as of March 31, 2011, our disclosure controls and procedures were effective to provide reasonable assurance that information required to be disclosed by us in the reports that we file or submit under the 1934 Act is recorded, processed, summarized, and reported within the time periods specified in the SEC's rules and forms and to provide reasonable assurance that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate to allow timely decisions regarding required disclosures.

Limitations on Controls

        Our disclosure controls and procedures are designed to provide reasonable assurance of achieving their objectives as specified above. Management does not expect, however, that our disclosure controls and procedures will prevent or detect all error and fraud. Any control system, no matter how well designed and operated, is based upon certain assumptions and can provide only reasonable, not absolute, assurance that its objectives will be met. Further, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud, if any, within the Partnership have been detected.

Changes in Internal Control Over Financial Reporting

        There were no changes in our internal control over financial reporting during the quarter ended March 31, 2011 that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

51

PART II—OTHER INFORMATION

Item 1.    Legal Proceedings

        Refer to Note 11 of the accompanying Notes to the Condensed Consolidated Financial Statements for information regarding legal proceedings.

Item 6.    Exhibits

4.1	(1)	Fifth Supplemental Indenture dated as of February 24, 2011, by and among MarkWest Energy Partners, L.P., MarkWest Energy Finance Corporation, the Subsidiary Guarantors named therein and Wells Fargo Bank, National Association, as trustee.
4.2	(1)	Second Supplemental Indenture dated as of February 24, 2011, by and among MarkWest Energy Partners, L.P., MarkWest Energy Finance Corporation, the Subsidiary Guarantors named therein and Wells Fargo Bank, National Association, as trustee.
4.3	(1)	Form of 6.5% Senior Notes due 2021 with attached notation of Guarantees (incorporated by reference to Exhibits A and B of Exhibit 4.2 hereto).
4.4	*	Sixth Supplemental Indenture dated as of March 10, 2011, by and among MarkWest Energy Partners, L.P., MarkWest Energy Finance Corporation, the Subsidiary Guarantors named therein and Wells Fargo Bank, National Association, as trustee.
4.5	*	Fourth Supplemental Indenture dated as of March 10, 2011, by and among MarkWest Energy Partners, L.P., MarkWest Energy Finance Corporation, the Subsidiary Guarantors named therein and Wells Fargo Bank, National Association, as trustee.
4.6	*	Third Supplemental Indenture dated as of March 10, 2011, by and among MarkWest Energy Partners, L.P., MarkWest Energy Finance Corporation, the Subsidiary Guarantors named therein and Wells Fargo Bank, National Association, as trustee.
10.1	*+	Purchase and Sale Agreement dated as of January 3, 2011 by and between EQT Gathering, LLC and MarkWest Energy Appalachia, L.L.C.
10.2	*+	Letter Agreement dated February 1, 2011 between EQT Gathering, LLC and MarkWest Energy Appalachia, L.L.C.
31.1	*	Certification of the Chief Executive Officer pursuant to Rule 13a-14(a) of the Securities Exchange Act, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2	*	Certification of the Chief Financial Officer pursuant to Rule 13a-14(a) of the Securities Exchange Act, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32.1	*	Certification of the Chief Executive Officer Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
32.2	*	Certification of the Chief Financial Officer Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
101	*	The following financial information from the quarterly report on Form 10-Q of MarkWest Energy Partners, L.P. for the quarter ended March 31, 2011, formatted in XBRL (eXtensible Business Reporting Language): (i) Condensed Consolidated Balance Sheets, (ii) Condensed Consolidated Statements of Operations, (iii) Condensed Consolidated Statements of Changes in Equity, (iv) Condensed Consolidated Statements of Cash Flows, and (v) Notes to the Condensed Consolidated Financial Statements, tagged as blocks of text.

(1)

Incorporated by reference to the Current Report on Form 8-K filed February 24, 2011.

52

*

Filed herewith

+

Application has been made to the Securities and Exchange Commission for confidential treatment of certain provisions of these exhibits. Omitted material for which confidential treatment has been requested and has been filed separately with the Securities and Exchange Commission.

53

SIGNATURES

        Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	MarkWest Energy Partners, L.P. (Registrant)
	By:	MarkWest Energy GP, L.L.C.,
		Its General Partner
Date: May 9, 2011	/s/ FRANK M. SEMPLE Frank M. Semple Chairman, President and Chief Executive Officer (Principal Executive Officer)
Date: May 9, 2011	/s/ NANCY K. BUESE Nancy K. Buese Senior Vice President & Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)

54

EX-4.4

Exhibit 4.4

MARKWEST ENERGY PARTNERS, L.P.,

MARKWEST ENERGY FINANCE CORPORATION

and

the Subsidiary Guarantors named herein

8½% SENIOR NOTES DUE 2016

SIXTH SUPPLEMENTAL INDENTURE

DATED AS OF MARCH 10, 2011

WELLS FARGO BANK, NATIONAL ASSOCIATION,

Trustee

This SIXTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of March 10, 2011, is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), each of the other parties identified on the signature page hereto (the “Subsidiary Guarantors”) and Wells Fargo Bank, National Association, a national banking association, as Trustee.

RECITALS

WHEREAS, the Issuers, the initial Subsidiary Guarantors and the Trustee entered into an Indenture, dated as of July 6, 2006 (as amended and supplemented by five supplemental indentures thereto, the “Indenture”), pursuant to which the Issuers have issued $275,000,000 in principal amount of 8½% Senior Notes due 2016 (the “Notes”);

WHEREAS, Section 9.01(d) of the Indenture provides that the Issuers, the Subsidiary Guarantors and the Trustee may amend or supplement the Indenture in order to add Subsidiary Guarantors pursuant to Section 4.13 or 5.01(c) thereof, without the consent of the Holders of the Notes; and

WHEREAS, all acts and things prescribed by the Indenture, by law and by the Certificate of Incorporation and the Bylaws (or comparable constituent documents) of the Issuers, of the Subsidiary Guarantors and of the Trustee necessary to make this Supplemental Indenture a valid instrument legally binding on the Issuers, the Subsidiary Guarantors and the Trustee, in accordance with its terms, have been duly done and performed;

NOW, THEREFORE, to comply with the provisions of the Indenture and in consideration of the above premises, the Issuers, the Subsidiary Guarantors and the Trustee covenant and agree for the equal and proportionate benefit of the respective Holders of the Notes as follows:

ARTICLE 1

Section 1.01. This Supplemental Indenture is supplemental to the Indenture and does and shall be deemed to form a part of, and shall be construed in connection with and as part of, the Indenture for any and all purposes.

Section 1.02. This Supplemental Indenture shall become effective immediately upon its execution and delivery by each of the Issuers, the Subsidiary Guarantors and the Trustee.

ARTICLE 2

From this date, in accordance with Section 4.13 or 5.01(c) of the Indenture and by executing this Supplemental Indenture, the Guarantors whose signatures appear below are subject to the provisions of the Indenture to the extent provided for in Article 10 thereunder.

ARTICLE 3

Section 3.01. Except as specifically modified herein, the Indenture and the Notes are in all respects ratified and confirmed (mutatis mutandis) and shall remain in full force and effect in accordance with their terms with all capitalized terms used herein without definition having the same respective meanings ascribed to them as in the Indenture.

Section 3.02. Except as otherwise expressly provided herein, no duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason of this Supplemental Indenture. This Supplemental Indenture is executed and accepted by the Trustee subject to all the terms and conditions set forth in the Indenture with the same force and effect as if those terms and conditions were repeated at length herein and made applicable to the Trustee with respect hereto.  Without limiting the generality of the foregoing, the Trustee shall not be responsible in any manner whatsoever for or with respect to any of the recitals or statements contained herein, all of which recitals or statements are made solely by the Issuers and the Subsidiary Guarantors, and the Trustee makes no representation with respect to any such matters.  Additionally, the Trustee makes no representations as to the validity or sufficiency of this Supplemental Indenture.

Section 3.03. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

Section 3.04. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement.

[NEXT PAGE IS SIGNATURE PAGE]

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed, all as of the date first written above.

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and ChiefFinancial Officer
MARKWEST ENERGY OPERATING COMPANY, L.L.C.
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C. MARKWEST ENERGY APPALACHIA, L.L.C. MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C. MARKWEST GAS MARKETING, L.L.C. MARKWEST GAS SERVICES, L.L.C. MARKWEST JAVELINA COMPANY, L.L.C. MARKWEST JAVELINA PIPELINE COMPANY, L.L.C. MARKWEST LIBERTY GAS GATHERING, L.L.C. MARKWEST MARKETING, L.L.C. MARKWEST NEW MEXICO, L.L.C. MARKWEST PINNACLE, L.L.C. MARKWEST PIPELINE COMPANY, L.L.C. MARKWEST PNG UTILITY, L.L.C. MARKWEST POWER TEX, L.L.C. MARKWEST TEXAS PNG UTILITY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C. MARKWEST OKLAHOMA GAS COMPANY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MATREX, L.L.C.
	By:	West Shore Processing Company L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

MARKWEST MCALESTER, L.L.C.
	By:	MarkWest Oklahoma Gas Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

WEST SHORE PROCESSING COMPANY L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Sixth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ Patrick T. Giordano
Name:	Patrick T. Giordano
Title:	Vice President

Signature Page to Sixth Supplemental Indenture

EX-4.5

Exhibit 4.5

MARKWEST ENERGY PARTNERS, L.P.,

MARKWEST ENERGY FINANCE CORPORATION, as Issuers,

and

the Subsidiary Guarantors named herein

8¾% SENIOR NOTES DUE 2018

FOURTH SUPPLEMENTAL INDENTURE

DATED AS OF MARCH 10, 2011

WELLS FARGO BANK, NATIONAL ASSOCIATION,

Trustee

This FOURTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of March 10, 2011, is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), each of the other parties identified on the signature page hereto (the “Subsidiary Guarantors”) and Wells Fargo Bank, National Association, a national banking association, as Trustee.

RECITALS

WHEREAS, the Issuers, the initial Subsidiary Guarantors and the Trustee entered into an Indenture, dated as of April 15, 2008 (as amended and supplemented by three supplemental indentures thereto, the “Indenture”), pursuant to which the Issuers have issued $500,000,000 in principal amount of 8¾% Senior Notes due 2018 (the “Notes”);

WHEREAS, Section 9.01(d) of the Indenture provides that the Issuers, the Subsidiary Guarantors and the Trustee may amend or supplement the Indenture in order to add Subsidiary Guarantors pursuant to Section 4.13 or 5.01(c) thereof, without the consent of the Holders of the Notes; and

WHEREAS, all acts and things prescribed by the Indenture, by law and by the Certificate of Incorporation and the Bylaws (or comparable constituent documents) of the Issuers, of the Subsidiary Guarantors and of the Trustee necessary to make this Supplemental Indenture a valid instrument legally binding on the Issuers, the Subsidiary Guarantors and the Trustee, in accordance with its terms, have been duly done and performed;

NOW, THEREFORE, to comply with the provisions of the Indenture and in consideration of the above premises, the Issuers, the Subsidiary Guarantors and the Trustee covenant and agree for the equal and proportionate benefit of the respective Holders of the Notes as follows:

ARTICLE 1

Section 1.01. This Supplemental Indenture is supplemental to the Indenture and does and shall be deemed to form a part of, and shall be construed in connection with and as part of, the Indenture for any and all purposes.

Section 1.02. This Supplemental Indenture shall become effective immediately upon its execution and delivery by each of the Issuers, the Subsidiary Guarantors and the Trustee.

ARTICLE 2

From this date, in accordance with Section 4.13 or 5.01(c) of the Indenture and by executing this Supplemental Indenture, the Guarantors whose signatures appear below are subject to the provisions of the Indenture to the extent provided for in Article 10 thereunder.

ARTICLE 3

Section 3.01. Except as specifically modified herein, the Indenture and the Notes are in all respects ratified and confirmed (mutatis mutandis) and shall remain in full force and effect in accordance with their terms with all capitalized terms used herein without definition having the same respective meanings ascribed to them as in the Indenture.

Section 3.02. Except as otherwise expressly provided herein, no duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason of this Supplemental Indenture. This Supplemental Indenture is executed and accepted by the Trustee subject to all the terms and conditions set forth in the Indenture with the same force and effect as if those terms and conditions were repeated at length herein and made applicable to the Trustee with respect hereto.  Without limiting the generality of the foregoing, the Trustee shall not be responsible in any manner whatsoever for or with respect to any of the recitals or statements contained herein, all of which recitals or statements are made solely by the Issuers and the Subsidiary Guarantors, and the Trustee makes no representation with respect to any such matters.  Additionally, the Trustee makes no representations as to the validity or sufficiency of this Supplemental Indenture.

Section 3.03. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

Section 3.04. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement.

[NEXT PAGE IS SIGNATURE PAGE]

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed, all as of the date first written above.

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and ChiefFinancial Officer
MARKWEST ENERGY OPERATING COMPANY, L.L.C.
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C. MARKWEST ENERGY APPALACHIA, L.L.C. MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C. MARKWEST GAS MARKETING, L.L.C. MARKWEST GAS SERVICES, L.L.C. MARKWEST JAVELINA COMPANY, L.L.C. MARKWEST JAVELINA PIPELINE COMPANY, L.L.C. MARKWEST LIBERTY GAS GATHERING, L.L.C. MARKWEST MARKETING, L.L.C. MARKWEST NEW MEXICO, L.L.C. MARKWEST PINNACLE, L.L.C. MARKWEST PIPELINE COMPANY, L.L.C. MARKWEST PNG UTILITY, L.L.C. MARKWEST POWER TEX, L.L.C. MARKWEST TEXAS PNG UTILITY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C. MARKWEST OKLAHOMA GAS COMPANY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MATREX, L.L.C.
	By:	West Shore Processing Company L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

MARKWEST MCALESTER, L.L.C.
	By:	MarkWest Oklahoma Gas Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

WEST SHORE PROCESSING COMPANY L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Fourth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ Patrick T. Giordano
Name:	Patrick T. Giordano
Title:	Vice President

Signature Page to Fourth Supplemental Indenture

EX-4.6

Exhibit 4.6

THIRD SUPPLEMENTAL INDENTURE

This THIRD SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of March 10, 2011, is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), each of the other parties identified on the signature page hereto (the “Subsidiary Guarantors”) and Wells Fargo Bank, National Association, a national banking association, as Trustee.

RECITALS

WHEREAS, the Issuers, the initial Subsidiary Guarantors and the Trustee entered into an Indenture, dated as of November 2, 2010 (as amended and supplemented by two supplemental indentures thereto, the “Indenture”), pursuant to which the Issuers have issued $500,000,000 in principal amount of 6¾% Senior Notes due 2020 (the “Notes”);

WHEREAS, Section 10.01 of the Indenture provides that the Issuers, the Subsidiary Guarantors and the Trustee may amend or supplement the Indenture in order to add Subsidiary Guarantors pursuant to Section 5.13 or 6.01(c) thereof, without the consent of the Holders of the Notes; and

WHEREAS, all acts and things prescribed by the Indenture, by law and by the Certificate of Incorporation and the Bylaws (or comparable constituent documents) of the Issuers, of the Subsidiary Guarantors and of the Trustee necessary to make this Supplemental Indenture a valid instrument legally binding on the Issuers, the Subsidiary Guarantors and the Trustee, in accordance with its terms, have been duly done and performed;

NOW, THEREFORE, to comply with the provisions of the Indenture and in consideration of the above premises, the Issuers, the Subsidiary Guarantors and the Trustee covenant and agree for the equal and proportionate benefit of the respective Holders of the Notes as follows:

ARTICLE 1

This Supplemental Indenture is supplemental to the Indenture and does and shall be deemed to form a part of, and shall be construed in connection with and as part of, the Indenture for any and all purposes.

This Supplemental Indenture shall become effective immediately upon its execution and delivery by each of the Issuers, the Subsidiary Guarantors and the Trustee.

ARTICLE II

From this date, in accordance with Section 5.13 or 6.01(c) of the Indenture and by executing this Supplemental Indenture, the Guarantors whose signatures appear below are subject to the provisions of the Indenture to the extent provided for in Article XI thereunder.

ARTICLE III

Except as specifically modified herein, the Indenture and the Notes are in all respects ratified and confirmed (mutatis mutandis) and shall remain in full force and effect in accordance with their terms with all capitalized terms used herein without definition having the same respective meanings ascribed to them as in the Indenture.

The Trustee accepts the amendments of the Indenture effected by this Supplemental Indenture and agrees to execute the trust created by the Indenture as hereby amended, but on the terms and conditions set forth in the Indenture, including the terms and provisions defining and limiting the liabilities and responsibilities of the Trustee, which terms and provisions shall in like manner define and limit its liabilities and responsibilities in the performance of the trust created by the Indenture as hereby amended, and without limiting the generality of the foregoing, the Trustee shall not be responsible in any manner whatsoever for or with respect to any of the recitals or statements contained herein, all of which recitals or statements are made solely by the Issuers and the Subsidiary Guarantors, and the Trustee makes no representation with respect to any such matters.  Additionally, the Trustee makes no representations as to the validity or sufficiency of this Supplemental Indenture

THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

The parties may sign any number of copies of this Supplemental Indenture.  Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement.

[NEXT PAGE IS SIGNATURE PAGE]

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed, all as of the date first written above.

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and ChiefFinancial Officer
MARKWEST ENERGY OPERATING COMPANY, L.L.C.
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C. MARKWEST ENERGY APPALACHIA, L.L.C. MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C. MARKWEST GAS MARKETING, L.L.C. MARKWEST GAS SERVICES, L.L.C. MARKWEST JAVELINA COMPANY, L.L.C. MARKWEST JAVELINA PIPELINE COMPANY, L.L.C. MARKWEST LIBERTY GAS GATHERING, L.L.C. MARKWEST MARKETING, L.L.C. MARKWEST NEW MEXICO, L.L.C. MARKWEST PINNACLE, L.L.C. MARKWEST PIPELINE COMPANY, L.L.C. MARKWEST PNG UTILITY, L.L.C. MARKWEST POWER TEX, L.L.C. MARKWEST TEXAS PNG UTILITY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C. MARKWEST OKLAHOMA GAS COMPANY, L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MATREX, L.L.C.
	By:	West Shore Processing Company L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member and Manager
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

MARKWEST MCALESTER, L.L.C.
	By:	MarkWest Oklahoma Gas Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer
MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Sole Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

WEST SHORE PROCESSING COMPANY L.L.C.
	By:	MarkWest Energy Operating Company, L.L.C.,
		its Managing Member
	By:	MarkWest Energy Partners, L.P.,
		its Managing Member
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Senior Vice President and Chief Financial Officer

Signature Page to Third Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ Patrick T. Giordano
Name:	Patrick T. Giordano
Title:	Vice President

Signature Page to Third Supplemental Indenture

EX-10.1

Exhibit 10.1

SPECIFIC TERMS IN THIS EXHIBIT HAVE BEEN REDACTED BECAUSE CONFIDENTIAL TREATMENT FOR THOSE TERMS HAS BEEN REQUESTED. THE REDACTED MATERIAL HAS BEEN SEPERATELY FILED WITH THE SECURITIES AND EXCHANGE COMMISSION, AND THE TERMS HAVE BEEN MARKED AT THE APPROPRIATE PLACE WITH TWO ASTERISKS (**).

EXECUTION VERSION

PURCHASE AND SALE AGREEMENT

By And Between

EQT GATHERING, LLC

And

MARKWEST ENERGY APPALACHIA, L.L.C.

Dated as of January 3, 2011

TABLE OF CONTENTS

ARTICLE I SALE AND TRANSFER OF ASSETS		1
Section 1.1.	Purchase and Sale	1
Section 1.2.	Time and Place of Closing	2
Section 1.3.	Adjustments to the Purchase Price	2
Section 1.4.	Deliveries by Seller	5
Section 1.5.	Deliveries by Buyer	6
Section 1.6.	Purchase Price Allocation	7
Section 1.7.	Nonassignable Assets	8
Section 1.8.	Real Property Consents	9
ARTICLE II REPRESENTATIONS AND WARRANTIES OF SELLER		10
Section 2.1.	Organization; Etc	10
Section 2.2.	Authority Relative to this Agreement and the Other Transaction Documents	11
Section 2.3.	Absence of Conflicts	11
Section 2.4.	Assets	12
Section 2.5.	Absence of Certain Changes	14
Section 2.6.	Litigation	14
Section 2.7.	Compliance with Law	14
Section 2.8.	Permits	15
Section 2.9.	Contracts	15
Section 2.10.	Employees and Employee Benefit Matters	15
Section 2.11.	Taxes	16
Section 2.12.	Environmental Matters	17
Section 2.13.	Intellectual Property	18
Section 2.14.	Condemnation	18
Section 2.15.	Bonds, Letters of Credit, Guarantees	18
Section 2.16.	Brokers; Finders and Fees	18
ARTICLE III DISCLAIMER OF REPRESENTATIONS AND WARRANTIES		19
ARTICLE IV REPRESENTATIONS AND WARRANTIES OF BUYER		19
Section 4.1.	Organization; Etc.	19
Section 4.2.	Authority Relative to this Agreement and the Other Transaction Documents	19
Section 4.3.	Absence of Conflicts	20
Section 4.4.	Availability of Funds	20
Section 4.5.	Litigation	20
Section 4.6.	Brokers; Finders and Fees	20
ARTICLE V TAX MATTERS		21
Section 5.1.	Preparation of Tax Returns	21

Section 5.2.	Responsibility for Taxes	21
Section 5.3.	Post-Closing Assistance	21
Section 5.4.	Conduct of Business	21
Section 5.5.	Pre- and Post-Closing Actions	22
Section 5.6.	Refunds of Certain Taxes Received by Buyer	23
Section 5.7.	Like-Kind Tax Exchange	23
Section 5.8.	Transfer Taxes	23
ARTICLE VI ADDITIONAL COVENANTS		24
Section 6.1.	Conduct of Business	24
Section 6.2.	Access to Records and Assets; Access Indemnity and Confidentiality	25
Section 6.3.	Regulatory Filings and Consents	26
Section 6.4.	Cooperation; Further Assurances	27
Section 6.5.	Operating Employees	28
Section 6.6.	Public Announcement	29
Section 6.7.	Insurance	29
Section 6.8.	Purchase Orders	30
Section 6.9.	Disclosure Schedules	30
Section 6.10.	Nuisance Litigation	30
Section 6.11.	Langley Plant Environmental Matters	30
Section 6.12.	Transition Plan	30
Section 6.13.	Expansion Plans	32
Section 6.14.	Confidentiality	32
ARTICLE VII CONDITIONS TO CLOSING		33
Section 7.1.	Conditions to Obligations of Seller and Buyer Under this Agreement	33
Section 7.2.	Additional Conditions to Seller’s Obligation	34
Section 7.3.	Additional Conditions to Buyer’s Obligation	34
ARTICLE VIII TERMINATION		35
Section 8.1.	Termination	35
Section 8.2.	Effect of Termination	35
ARTICLE IX SURVIVAL AND INDEMNIFICATION		36
Section 9.1.	Survival Periods	36
Section 9.2.	Seller’s Agreement to Indemnify	36
Section 9.3.	Buyer’s Agreement to Indemnify	39
Section 9.4.	Third Party Indemnification	41
Section 9.5.	Insurance	43
Section 9.6.	No Duplication	43
Section 9.7.	Amount of Losses	43
Section 9.8.	Remedies Exclusive	43
Section 9.9.	Casualty and Condemnation	44
Section 9.10.	No Special Damages	44
Section 9.11.	Conspicuous Legends; Nature of Indemnification	44

ii

ARTICLE X MISCELLANEOUS PROVISIONS		45
Section 10.1.	Amendment and Modification	45
Section 10.2.	Entire Agreement; Assignment	45
Section 10.3.	Severability	45
Section 10.4.	Notices	45
Section 10.5.	Governing Law, Exclusive Jurisdiction and Waiver of Jury Trial	46
Section 10.6.	Descriptive Headings	47
Section 10.7.	Counterparts	47
Section 10.8.	Fees and Expenses	47
Section 10.9.	Interpretation	48
Section 10.10.	No Third Party Beneficiaries	48
Section 10.11.	No Waivers	48
Section 10.12.	Specific Performance	49
Section 10.13.	Facsimile Signature	49
ARTICLE XI DEFINITIONS		49
Section 11.1.	Certain Definitions	49

iii

EXHIBITS:

Exhibit A-1	Processing Facilities and Ranger NGL Pipeline
Exhibit A-2	Personal Property
Exhibit A-3	Real Property Interests
Exhibit A-4	Permits
Exhibit A-5	Assigned Contracts
Exhibit A-6	Radio Licenses
Exhibit B	Excluded Assets

DISCLOSURE SCHEDULE:

Section 2.3(b)	Real Property Consents
Section 2.4(a)	Title Matters
Section 2.4(f)	Condition of Certain Assets
Section 2.6	Litigation
Section 2.11	Taxes
Section 2.12	Environmental Matters
Section 2.13	Intellectual Property Licenses
Section 6.1	Conduct of Business
Section 6.8	Purchase Orders
Section 10.9	Knowledge Individuals

TABLE OF DEFINED TERMS

The following terms have the meaning defined for such terms in the Sections set forth below.  All other capitalized terms in this Agreement have the meanings set forth in Section 11.1.

Defined Term	Section
Accounting Arbitrator	Section 1.3(d)
Agreement	Preamble
Allocation	Section 1.6
Assignment	Section 1.4(j)
Assigned Purchase Orders	Section 6.12(c)
Benefits Schedule	Section 6.5(a)
Big Sandy Compression Expansion	Section 6.13
Buyer	Preamble
Buyer Closing Statement	Section 1.3(d)
Buyer Damages	Section 9.2(a)
Buyer Fundamental Representations	Section 9.1
Buyer Indemnitees	Section 9.2(a)
Buyer Master Agreements	Section 6.12(c)
Buyer Material Adverse Effect	Section 4.1
Buyer Review Period	Section 1.3(d)
Claim	Section 9.4
Closing	Section 1.2
Closing Adjustment	Section 1.3(b)
Closing Date	Section 1.2
Compensation Schedule	Section 2.10(b)
Conveyances	Section 1.4(h)
Disclosure Schedule	Preamble
Engineering Firm	Section 6.13
EQT Processing Facilities	Section 1.8(c)
EQT Processing Facilities Agreement	Section 1.8(c)
Estimated Closing Adjustment	Section 1.3(b)
February 2010 Letter	Section 2.4(h)
Gas Processing Agreement	Section 1.4(d)
Hired Employees	Section 6.5
HSR Approval	Section 7.1
Indemnification Ceiling	Section 9.2(b)(i)
Indemnification Deductible	Section 9.2(b)(i)
Indemnified Party	Section 9.4(a)
Indemnifying Party	Section 9.4(a)
Langley Plant 3	Section 6.13
Langley Site Development Plans	Section 6.13

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Defined Term	Section
NGL Exchange Agreement	Section 1.4(g)
Nonassignable Asset	Section 1.7(a)
Nuisance Proceeding	Section 6.10
Omnibus Amendment	Section 1.4(h)
Operating Employees	Section 2.10(b)
Permits	Section 2.8
Propak	Section 6.12(d)
Purchase Price	Section 1.1
Real Property Agreements	Section 2.4(c)
Real Property Consents	Section 2.3(b)
Retained Master Agreements	Section 6.12(c)
Seller	Preamble
Seller Closing Statement	Section 1.3(d)
Seller Damages	Section 9.3(a)
Seller Fundamental Representations	Section 9.1
Seller Indemnitees	Section 9.3(a)
Seller Material Adverse Effect	Section 2.1
Seller Policies	Section 6.7
Seller Tax Representation	Section 9.1
Survival Period	Section 9.1
Tax Audit	Section 5.4(a)
Tax Indemnified Person	Section 5.4(a)
Tax Indemnifying Person	Section 5.4(a)
Tax Items	Section 5.4(c)
Termination Date	Section 8.1(d)
Transfer Taxes	Section 5.8
Transition IT System	Section 6.12(b)
Unadjusted Purchase Price	Section 1.1

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PURCHASE AND SALE AGREEMENT

This PURCHASE AND SALE AGREEMENT (this “Agreement”) is dated as of January 3, 2011, by and between EQT Gathering, LLC, a Delaware limited liability company (“Seller”) and MarkWest Energy Appalachia, L.L.C., a Delaware limited liability company (“Buyer”).  Seller and Buyer are referred to herein as the “Parties” and individually as a “Party.”  Capitalized terms used but not otherwise defined elsewhere in this Agreement shall have the respective meanings given to such terms in ARTICLE XI.

A.            Seller owns and operates certain Assets, including the Processing Facilities located near Langley and Maytown, Kentucky, and the Ranger NGL Pipeline.

B.            Seller desires to sell to Buyer (and/or a Buyer Subsidiary), and Buyer (and/or such Buyer Subsidiary) desires to purchase from Seller, the Assets, free and clear of all Liens other than Permitted Encumbrances, upon the terms and subject to the conditions set forth herein.

C.            At the Closing of the transactions contemplated by this Agreement, EQT Energy, LLC, a Delaware limited liability company and Affiliate of Seller (“EQT Energy”), and Buyer will enter into the Gas Processing Agreement, whereby, among other things, Buyer will commit to continue to process EQT Energy’s Gas at the Processing Facilities and deliver Plant Products attributable thereto to the NGL Delivery Point in consideration of EQT Energy’s commitment to pay the Processing Fees described therein.

D.            At the Closing of the transactions contemplated by this Agreement, EQT Energy and Buyer will enter into the NGL Exchange Agreement, whereby, among other things, Buyer will agree to complete the Ranger II NGL Pipeline described therein and exchange Plant Products attributable to EQT Energy’s Gas delivered by EQT Energy to the NGL Delivery Point located at the tailgate of the Processing Facilities for Fractionated Products delivered by Processor to the tailgate of the Siloam Fractionation Plant in consideration of EQT Energy’s commitment to pay the fees described therein.

NOW, THEREFORE, in consideration of the foregoing and the mutual representations, warranties, covenants and agreements contained herein, and intending to be legally bound hereby, the Parties agree as follows:

ARTICLE I
SALE AND TRANSFER OF ASSETS

Section 1.1.            Purchase and Sale.

(a)           Upon the terms and subject to the conditions set forth in this Agreement, at the Closing, Seller shall sell, convey, assign, transfer and deliver to Buyer (and/or a Buyer Subsidiary), and Buyer (and/or such Buyer Subsidiary) shall purchase, acquire and accept from Seller, the Assets, free and clear of all

Liens other than Permitted Encumbrances, and assume the Assumed Liabilities with respect thereto, in consideration for which, Buyer (on its own behalf, or as applicable, as agent for a Buyer Subsidiary) will pay to Seller an amount equal to $230,000,000 (the “Unadjusted Purchase Price”), adjusted as provided in Section 1.3 (as adjusted, the “Purchase Price”).

(b)           Seller shall retain, and shall be fully responsible for paying, performing and discharging when due, and Buyer (and/or any Buyer Subsidiary) shall not assume or have any responsibility for, any Retained Liability.

Section 1.2.            Time and Place of Closing.  Upon the terms and subject to the conditions of this Agreement, the closing of the transactions contemplated by this Agreement (the “Closing”) will take place at the offices of Seller, located at EQT Plaza, 625 Liberty Avenue, Suite 1700, Pittsburgh, Pennsylvania 15222, at 10:00 A.M. Eastern time on the first Business Day of the month following satisfaction or waiver of all of the conditions to the obligations of the parties set forth in ARTICLE VII (other than actions to be taken or items to be delivered at Closing, but subject to satisfaction of such conditions at the Closing); provided that there are at least 10 days between the satisfaction of such conditions and such date; provided further, that in the event there are less than 10 days between the satisfaction of such conditions and the first Business Day of the following month, the Closing will take place on the first Business Day of the second month following satisfaction of such conditions, or such date as the parties may mutually agree (the “Closing Date”).

Section 1.3.            Adjustments to the Purchase Price.

(a)           The Unadjusted Purchase Price shall be adjusted as follows:

(i)            increased by an amount equal to the NGL Inventory Value for the volume of each of propane, isobutane, normal butane and natural gasoline included in the aggregate NGL volume, as of the Effective Time, in the Ranger NGL Pipeline, the stock tanks at the Ranger Truck Terminal and loaded in trucks for transport to the Ranger Truck Terminal or the Siloam Fractionation Plant;

(ii)           increased by the net amount of all prepaid expenses (including prepaid Taxes) to the extent applying to the ownership and operation of the Assets following the Effective Time; and

(iii)          decreased for costs or expenses, including Taxes (other than income, franchise and similar taxes), incurred with respect to the operation of the Assets prior to the Effective Time but paid by Buyer after the Effective Time.

Should Buyer or its Affiliates pay after the Effective Time any expenses for which Seller is responsible under this Section 1.3(a) and which have not been accounted

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for in the final Closing Adjustment in accordance with Section 1.3(d), Seller shall reimburse Buyer (or its Affiliates, as applicable) promptly after receipt of such Person’s invoice, accompanied by copies of the relevant vendor or other invoice and proof of payment.

(b)           For purposes of determining the amount of cash to be paid as the Estimated Purchase Price by Buyer to Seller at the Closing pursuant to Section 1.5(a), Seller shall prepare and deliver, not less than two Business Days before the Closing Date, a good faith estimate of each adjustment to be made pursuant to Section 1.3(a) (the “Closing Adjustment”) determined in accordance with the US GAAP (except as set forth in Section 1.3(c)) as of the Closing Date (such estimated adjustments, the “Estimated Closing Adjustment”), which shall be reasonably acceptable to Buyer.    As used in this Agreement, the “Estimated Purchase Price” shall mean an amount equal to the Unadjusted Purchase Price plus an amount equal to the Estimated Closing Adjustment (which may be positive or negative).

(c)           For purposes of determining the Estimated Closing Adjustment, Seller shall measure, determine or estimate in good faith, based upon historical inventory and volume lists provided by Seller to Buyer, the physical inventory and composition of the NGL volumes in the Ranger NGL Pipeline, the stock tanks at the Ranger Truck Terminal and loaded in trucks for transport to the Ranger Truck Terminal or the Siloam Fractionation Plant as of the Effective Time to determine the volume and composition of NGLs as near as possible to the Effective Time for purposes of the adjustment in Section 1.3(a)(i).  The Parties agree that, notwithstanding the fact each location identified in Section 1.3(a)(i) has not been subject to a physical inventory as of the Effective Time, the physical inventory taken by Seller under this Section 1.3(b) shall constitute the NGL volumes included in the Assets and subject to adjustment in accordance with Section 1.3(b).

(d)           As soon as reasonably practicable after the Closing but not later than the 60th day following the Closing Date, Seller shall prepare and deliver to Buyer a statement setting forth its calculation of the Purchase Price and the Closing Adjustment based on the most recent actual figures for each adjustment and determined in accordance with the US GAAP (the “Seller Closing Statement”).  Seller shall at Buyer’s request make reasonable documentation available to Buyer and its representatives to support the information set forth in the Seller Closing Statement (including access to employees of Seller and supporting schedules, analyses, work papers and underlying records and documentation as are reasonably necessary or helpful in Buyer’s review of such statement).  Seller shall provide all other cooperation reasonably requested by Buyer in connection with Buyer’s review of the Seller Closing Statement.  As soon as reasonably practicable but not later than the 45th day following receipt of

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Seller’s statement hereunder (the “Buyer Review Period”), Buyer may deliver to Seller a written report containing any changes that Buyer proposes be made to the Seller Closing Statement (the “Buyer Closing Statement”).  Seller may deliver a written report to Buyer during this same period reflecting any changes that Seller proposes to be made in the Seller Closing Statement as a result of additional information received after the statement was prepared; provided that the Buyer Review Period shall be deemed to recommence upon any such delivery by Seller.  The Parties shall use good faith efforts to agree on the final statement of the Purchase Price and the Closing Adjustment no later than 75 days after delivery of the Seller Closing Statement.  In the event that the Parties hereto cannot reach agreement within such period of time, either Party may refer the items of the Closing Adjustment which are in dispute to Ernst & Young LLP or another nationally-recognized independent accounting firm or consulting firm mutually acceptable to the Parties (the “Accounting Arbitrator”), for review and final determination by arbitration.  Should the initial Accounting Arbitrator fail or refuse to agree to serve as Accounting Arbitrator within 20 days after written request from any Party to serve, and the Parties  fail to agree in writing on a replacement Accounting Arbitrator within 10 days after the end of that 20-day period, or should no replacement Accounting Arbitrator agree to serve within 45 days after the original written request pursuant to this sentence, the Accounting Arbitrator shall be appointed by the Philadelphia office of the American Arbitration Association.  The Accounting Arbitrator shall conduct the arbitration proceedings in Pittsburgh, Pennsylvania in accordance with the Commercial Arbitration Rules of the American Arbitration Association, to the extent such rules do not conflict with the terms of this Section 1.3(d).  The Accounting Arbitrator’s determination shall be made within 45 days after submission of the matters in dispute and shall be final and binding on all Parties, without right of appeal.  In determining the proper amount of the Closing Adjustment and the Purchase Price, the Accounting Arbitrator shall be bound by the terms of this Section 1.3 and may not increase the Purchase Price above the Purchase Price proposed by Seller in the Seller Closing Statement nor decrease the Purchase Price below the Purchase Price proposed by Buyer in the Buyer Closing Statement, as applicable.  The Accounting Arbitrator shall act as an expert for the limited purpose of determining the specific disputed aspects of the Closing Adjustment submitted by either Party (which shall be consistent with the contents of the Seller Closing Statement or Buyer Closing Statement except as otherwise agreed to in writing by the Parties) and may not award damages, interest (except as expressly provided for in this Section 1.3(d)) or penalties to any Party with respect to any matter.  The Parties shall each bear its own legal fees and other costs of presenting its case, including one half of the costs and expenses of the Accounting Arbitrator, respectively.  Within 10 days after the earlier of (i) the expiration of Buyer’s 45 day review period without delivery of the Buyer Closing Statement or (ii) the date on which the Parties or the Accounting Arbitrator finally

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determine the Purchase Price, (x) Buyer shall pay to Seller the amount by which the portion of the Purchase Price to which Seller is entitled exceeds the Estimated Purchase Price, or (y) Seller shall pay to Buyer the amount by which the Estimated Purchase Price exceeds the Purchase Price to which Seller is entitled, as applicable.  Any post-Closing payment pursuant to this Section 1.3(d) shall bear interest from the Closing Date to the date of payment at rate per annum equal to the prime rate of interest as reported in The Money Rates table of The Wall Street Journal from time to time in effect, plus four percent.     Buyer and Seller agree that any payments made pursuant to this Section 1.3 shall be allocated in a manner consistent with the allocation referred to in Section 1.6.

(e)           All payments made or to be made under this Agreement to Seller shall be made by electronic transfer of immediately available funds to a bank and account specified by Seller in writing to Buyer, for the credit of Seller.  All payments made or to be made hereunder to Buyer shall be by electronic transfer or immediately available funds to a bank and account specified by Buyer in writing to Seller, for the credit of Buyer.

Section 1.4.            Deliveries by Seller.  Subject to the terms and conditions hereof, at the Closing, Seller will deliver the following to Buyer:

(a)           a certificate of the secretary of Seller respecting, and to which is attached, (i) the certificate of formation of Seller; (ii) resolutions of Seller authorizing the execution of this Agreement and the Other Transaction Documents and the consummation of the transaction contemplated hereby and thereby (to the extent required under Seller’s organizational documents); (iii) resolutions of each Affiliate of Seller who is a party to any Other Transaction Document authorizing the execution of such Other Transaction Document(s) to which it is a party and the consummation of the transactions contemplated thereby (to the extent required under the organization documents of such Affiliate) and (iv) a certificate respecting the incumbency and true signatures of the officers who execute this Agreement and any other agreement, certificate or document related hereto or executed in connection herewith on behalf of Seller or any of its Affiliates;

(b)           the officer’s certificates referred to in Section 7.3(a) and (b);

(c)           a duly executed certificate, in a form reasonably satisfactory to Buyer, to the effect that EQT Gathering, Inc., a Pennsylvania corporation, is not a foreign person and otherwise meeting the requirements of Treasury Regulations Section 1.1445-2(b);

(d)           a duly executed counterpart of the Gas Processing Agreement, dated as of the Closing Date, by and between EQT Energy and Buyer,

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substantially in the form agreed to by the Parties on or prior to the date hereof (the “Gas Processing Agreement”);

(e)           [reserved];

(f)            a duly executed counterpart of the Big Sandy Shared Services Agreement;

(g)           a duly executed counterpart of the NGL Exchange Agreement, dated as of the Closing Date, by and between EQT Energy and Buyer, substantially in the form agreed to by the Parties on or prior to the date hereof (the “NGL Exchange Agreement”);

(h)           a duly executed counterpart of the Omnibus Amendment, dated as of the Closing Date, by and between EQT Energy, EQT Production Company, Seller, Buyer, MarkWest Hydrocarbon, Inc. and MarkWest Energy Partners, L.P. substantially in the form agreed to by the Parties on or prior to the date hereof (the “Omnibus Amendment”);

(i)            special warranty deeds with respect to all Real Property Interests, substantially in the form agreed to by the Parties on or prior to the date hereof (the “Conveyances”), duly executed by Seller, in sufficient duplicate originals to allow recording in all appropriate jurisdictions and offices;

(j)            a duly executed counterpart of the Assignment, Bill of Sale and Assumption Agreement, dated as of the Closing Date, by and between the Parties (or by and between Seller and a Buyer Subsidiary, as applicable), substantially in the form agreed to by the Parties on or prior to the date hereof (each, an “Assignment”); and

(k)           any other documents required pursuant to this Agreement or reasonably requested by Buyer.

Section 1.5.            Deliveries by Buyer.  Subject to the terms and conditions hereof, at the Closing, Buyer will deliver the following to Seller:

(a)           the Estimated Purchase Price, by wire transfer of immediately available funds to the account or accounts designated by Seller in writing prior to the Closing Date;

(b)           a certificate of the secretary of Buyer respecting, and to which is attached, (i) the certificate of formation of Buyer; (ii) resolutions of Buyer authorizing the execution of this Agreement and the Other Transaction Documents and the consummation of the transaction contemplated hereby and thereby (to the extent required under Buyer’s organizational documents); and (iii) 

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a certificate respecting the incumbency and true signatures of the officers who execute this Agreement, the Gas Processing Agreement and any other agreement, certificate or document related hereto or executed in connection herewith on behalf of Buyer;

(c)           the officer’s certificates referred to in Section 7.2(a) and (b);

(d)           a duly executed counterpart of the Gas Processing Agreement;

(e)           [reserved];

(f)            a duly executed counterpart of the Big Sandy Shared Services Agreement;

(g)           a duly executed counterpart of the NGL Exchange Agreement;

(h)           a duly executed counterpart of the Omnibus Amendment;

(i)            duly executed counterparts of the Conveyances in sufficient duplicate originals to allow recording in all appropriate jurisdictions and offices;

(j)            a duly executed counterpart of each Assignment; and

(k)           any other document required pursuant to this Agreement or reasonably requested by Seller.

Section 1.6.            Purchase Price Allocation.  Buyer shall, within the later of (a) 60 days following the Closing, or (b) 15 days after the final Purchase Price is determined under Section 1.3, prepare and deliver to Seller for its review and approval (i) an allocation of the Purchase Price among the Assets consistent with the principles of Section 1060 of the Code and the Treasury regulations promulgated thereunder (the “Allocation”) and (ii) a draft Internal Revenue Service Form 8594 (Asset Allocation Statement) consistent therewith.  Any disputes with respect to the Allocation that cannot be resolved by the Parties shall be referred to the Accounting Arbitrator for resolution with such resolution to be made within 30 days of such referral. All expenses of the Accounting Arbitrator shall be shared by the Seller and Buyer equally.  The Parties agree (A) to file Internal Revenue Service Form 8594 (Asset Allocation Statement) as well as any similar state or local form consistently with the Allocation, in each case as agreed, and (B) that neither Seller nor Buyer or any of their respective Affiliates or direct or indirect owners shall take a position on any Tax Return, or before any Governmental Authority in connection with the examination of a Tax Return or in any judicial proceeding, that is in any manner inconsistent with the terms of the Allocation, except as required by applicable Law.

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Section 1.7.            Nonassignable Assets.

(a)           Nothing in this Agreement, nor the consummation of the transactions contemplated hereby, shall be construed as an attempt or agreement to assign or transfer any Asset (including any Assigned Contract) to Buyer or a Buyer Subsidiary, as applicable, which by its terms or by Law is nonassignable without a Consent (a “Nonassignable Asset”), unless and until such Consent shall have been obtained.  Seller shall advise Buyer in writing at least five Business Days prior to the Closing (a) of any Material Contract with respect to which a Consent of the counterparty is required for assignment and for which such Consent has not been obtained and (b) if Seller has received notice (whether written or oral) that any such third Person will not agree to the assignment of any Material Contract to Buyer or a Buyer Subsidiary, as applicable, hereunder at the Closing.   To the extent permitted by applicable Law and by the terms of the applicable Nonassignable Asset, such Nonassignable Asset shall be held, as of and from the Closing Date, by Seller for the benefit and burden of Buyer or a Buyer Subsidiary, as applicable, and the covenants and obligations thereunder shall be fully performed by Buyer or such Buyer Subsidiary, as applicable, on Seller’s behalf and all rights and Liabilities existing thereunder shall be for Buyer’s or such Buyer Subsidiary’s account, as applicable.  For the avoidance of doubt, the designation of an Asset as a Nonassignable Asset does not render it an Excluded Asset.

(b)           To the extent permitted by applicable Law and by the terms of the applicable Nonassignable Asset, Seller and Buyer shall take, or cause to be taken, such actions as the other party may reasonably request that are required to be taken or appropriate in order to provide Buyer or a Buyer Subsidiary, as applicable, with the benefits and burdens of the Nonassignable Assets.  Seller shall promptly pay over to Buyer or such Buyer Subsidiary, as applicable, the net amount (after de minimis reasonable administrative expenses and an adjustment for Taxes consistent with Section 1.3 placing each party as nearly as possible in the same position as if the Nonassignable Asset had been transferred to Buyer or such Buyer Subsidiary, as applicable, on the Closing Date), of all payments received by it in respect of all Nonassignable Assets and Buyer shall indemnify Seller for all Losses attributable to Seller’s holding of all Nonassignable Assets

(c)           The Parties shall continue after the Closing to use all commercially reasonable efforts to obtain the applicable Consents to assign any Nonassignable Asset that were not obtained prior to the Closing.

(d)           The provisions of this Section 1.7 shall not apply in respect of the Real Property Consents, which shall be governed by Section 1.8.

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Section 1.8.            Real Property Consents.

(a)           Seller shall identify, with respect to the Assets, all Real Property Consents and other provisions restricting assignment without Consent that would be applicable to the transactions contemplated hereby and the names and addresses of the parties holding such Real Property Consents.  Seller will request, from the parties so identified (and in accordance with the documents creating such rights), and will use commercially reasonable efforts to obtain, execution of all Real Property Consents.  During such period in which the applicable Asset is not capable of being assigned to Buyer or a Buyer Subsidiary, as applicable, due to the failure to obtain an execution of a Real Property Consent, the Parties mutually agree, as is reasonably practicable, to cooperate to obtain an execution of such Real Property Consent or to make or cause to be made such arrangements as may be reasonably necessary or requested by Buyer to enable Buyer or such Buyer Subsidiary, as applicable, to receive all the economic benefits or same or similar rights with respect to such Asset.

(b)           Real Property Interests with respect to which a Real Property Consent has not been obtained on or before the day that is three Business Days prior to Closing shall be deemed to be excluded from the Assets conveyed to Buyer or a Buyer Subsidiary, as applicable, at Closing, but the Unadjusted Purchase Price shall not be reduced.

(c)           With respect to any Real Property Interest upon which any pipeline comprising part of the Processing Facilities or the Ranger NGL Pipeline is located, if, under the terms of such Real Property Interest, a Real Property Consent is required prior to the assignment of such Real Property Interest to Buyer or a Buyer Subsidiary, as applicable, and such Real Property Consent has not been obtained prior to the Closing, this Agreement shall not constitute an agreement to convey at the Closing such Real Property Interest or the portions of such Processing Facilities or Ranger NGL Pipeline that are located upon such Real Property Interest.  In such case, the Parties may agree that (i) with respect to the portions of such Processing Facilities or Ranger NGL Pipeline not conveyed at the Closing (the “EQT Processing Facilities”), the Parties shall enter into an agreement (the “EQT Processing Facilities Agreement”), the form and substance of which shall be mutually agreed by the Parties, that provides Buyer or such Buyer Subsidiary, as applicable, to the commercially reasonable extent possible, with the rights, benefits and burdens with respect to the EQT Processing Facilities that Buyer or such Buyer Subsidiary, as applicable, would have received had such EQT Processing Facilities been conveyed to Buyer or such Buyer Subsidiary, as applicable, at the Closing and (ii) the other portions of such Processing Facilities or Ranger NGL Pipeline and the related Real Property Interests shall be conveyed to Buyer or such Buyer Subsidiary, as applicable, at the Closing.  With respect to any portion of the EQT Processing Facilities and related Real Property Interests to

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which an EQT Processing Facilities Agreement applies, when the applicable Real Property Consents are obtained, Seller shall convey the applicable portions of the EQT Processing Facilities and assign, pursuant to a special warranty deed, such related Real Property Interests to Buyer or such Buyer Subsidiary, as applicable, within 10 days following receipt of such Real Property Consent, and the EQT Processing Facilities Agreement with respect to such portions of the EQT Processing Facilities shall terminate.  During the term of any such EQT Processing Facilities Agreement, Seller shall not convey, or allow any Liens by, through, or under Seller to attach to, the applicable portion of the EQT Processing Facilities or the related Real Property Interests covered by such EQT Processing Facilities Agreement.  Additionally, Buyer or such Buyer Subsidiary, as applicable, may terminate such EQT Processing Facilities Agreement at any time by giving 60 days’ notice.  At the time of termination of the EQT Processing Facilities Agreement, Seller shall convey to Buyer or such Buyer Subsidiary, as applicable, the remaining rights they may have in the EQT Processing Facilities and, assign, to the extent related to such Processing Facilities or portion of Ranger NGL Pipeline, the Real Property Interests pursuant to a special warranty deed.

(d)           The Parties shall continue after the Closing to use all commercially reasonable efforts to obtain any Real Property Consent that was not obtained prior to the Closing.

ARTICLE II
REPRESENTATIONS AND WARRANTIES OF SELLER

Seller hereby represents and warrants to Buyer as follows, except as set forth on the disclosure schedule document being delivered to Buyer concurrently herewith (any such schedule delivered by the Parties under this Agreement is referred to herein as the “Disclosure Schedule”):

Section 2.1.            Organization; Etc.  Seller (a) is a limited liability company duly formed, validly existing and in good standing under the laws of the State of Delaware, (b) has all requisite power and authority to own the Assets, and to carry out its business substantially as now conducted, (c) is duly qualified and in good standing to do business in each of the States of Kentucky, West Virginia and Pennsylvania and (d) is duly qualified and in good standing to do business in each jurisdiction in which the ownership and operation of its Assets makes such qualification necessary, except in the case of clause (d) where the failure to be so qualified and in good standing would not, individually or in the aggregate, have a Seller Material Adverse Effect.  Each Affiliate of Seller that is or will be a party to any Other Transaction Document (i) is duly organized, validly existing and in good standing under the Laws of its jurisdiction of organization, (ii) has all requisite power and authority to own its assets and carry out its business substantially as now conducted and (iii) is duly qualified and in good standing to do business in each jurisdiction in which the ownership and operation of its assets makes such qualification necessary, except in the case of clause (iii) where the failure to be so qualified and in good

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standing would not have a materially adverse effect upon such Affiliate’s ability to carry out its obligations under, and to consummate the transactions contemplated by such Other Transaction Document.

Section 2.2.            Authority Relative to this Agreement and the Other Transaction Documents.  Seller and each of its Affiliates that is or will be a party to any of the Other Transaction Documents, has all requisite limited liability company power, authority and capacity to execute and deliver this Agreement and the Other Transaction Documents to which it is a party and to consummate the transactions contemplated hereby and thereby.  The execution and delivery of this Agreement and the Other Transaction Documents and the consummation of the transactions contemplated hereby and thereby have been or will be, as applicable, duly and validly authorized by all requisite limited liability company action on the part of Seller and each such Affiliate.  This Agreement has been, and the Other Transaction Documents will be, duly and validly executed and delivered by Seller and each such Affiliate, as applicable, and, assuming this Agreement has been, and the Other Transaction Documents to which Buyer is a party will be, duly authorized, executed and delivered by Buyer, constitutes or will constitute, as applicable, a valid and binding agreement of Seller and each such Affiliate, enforceable against Seller and each such Affiliate in accordance with its terms, except that (a) such enforcement may be subject to any bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer or other laws, now or hereafter in effect, relating to or limiting creditors’ rights generally and (b) enforcement of this Agreement and the Other Transaction Documents, including, among other things, the remedy of specific performance and injunctive and other forms of equitable relief, may be subject to equitable defenses and to the discretion of the court before which any proceeding therefor may be brought.

Section 2.3.            Absence of Conflicts.

(a)           The execution and delivery of this Agreement and the Other Transaction Documents by Seller or, if applicable in the case of the Other Transaction Documents, any of its Affiliates, and the consummation by Seller  and any such Affiliate of the transactions contemplated hereby and thereby do not and will not (i) conflict with or result in any breach of any provision of Seller’s or such Affiliate’s limited liability company agreement, certificate of formation or other organizational documents, (ii) result in a violation or breach of, or constitute (with or without due notice or lapse of time or both) a default (or give rise to any right of termination, cancellation or acceleration) under, or require any Consent under, any material note, bond, mortgage, indenture or other financing instrument or obligation to which Seller or such Affiliate is a party or by which Seller or the Assets or such Affiliate or its assets are bound, (iii) violate any material order, writ, injunction, decree or Laws applicable to Seller or the Assets or such Affiliate or its assets, (iv) require any filing with, or the obtaining of any permit, authorization, Consent or approval of, any Governmental Authority that has not been made or obtained, or (v) except with respect to the Real Property Consents, Assigned Contracts and Radio Licenses, require the Consent of any third Person,

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except in the case of clauses (iv) and (v) of this Section 2.3(a) for any such matters which, individually or in the aggregate, would not adversely affect the ability of Seller or such Affiliate to consummate the transactions contemplated hereby or thereby or result in a Seller Material Adverse Effect.

(b)           Section 2.3(b) of the Disclosure Schedule identifies with a single asterisk all Consents and other restrictions on assignment with respect to the Real Property Interests that are required (or would be applicable) in connection with the transfer of the Real Property Interests to Buyer in accordance with the terms and conditions of this Agreement (the “Real Property Consents”).

Section 2.4.            Assets.

(a)           Except as set forth in Section 2.4(a) of the Disclosure Schedule, there is no Proceeding pending or Demand filed, nor have there been any Proceedings or Demands filed since January 1, 2010, alleging that an EQT Subsidiary does not have Defensible Title to the Assets.

(b)           An EQT Subsidiary is the sole legal and equitable owner of each parcel of the Owned Real Property described on Exhibits A-3-1 to A-3-4, inclusive.  With respect to each parcel of Owned Real Property, (i) an EQT Subsidiary has marketable title, free and clear of all Liens other than Permitted Encumbrances; (ii) there are no leases, subleases, licenses, concessions, or other agreements, written or oral, granting to any Person the right of use or occupancy of any portion of such Owned Real Property; (iii) there are no outstanding options, rights of first offer, or rights of first refusal to purchase such Owned Real Property, or any portion thereof or interest therein; and (iv) notwithstanding the terms of Section 2.4, there are no Proceedings pending or Demands filed or, to the knowledge of Seller, threatened or alleged, with respect to the marketable title of all or any part of the Owned Real Property.

(c)           Seller has provided to Buyer complete and accurate copies of all real property agreements, leases, subleases, licenses, occupancy agreements and other similar agreements relating to the Ranger NGL Pipeline, the Processing Facilities, and all Lease and Easement Properties (including all modifications thereto and all notices exercising renewal, expansion, termination or other material rights), which are described in Exhibits A-3-5 and A-5, and are individually each a “Real Property Agreement” and collectively referred to herein as the “Real Property Agreements”.  An EQT Subsidiary has Defensible Title to or has a valid leasehold interest or license in the Ranger NGL Pipeline, the Processing Facilities, and all Lease and Easement Properties, free and clear of any and all Liens, except for Permitted Encumbrances.  The Real Property Agreements are in full force and effect.    No Real Property Agreement is subject to any prime, ground or master lease, mortgage, deed of trust or other Lien or

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interest which would entitle the interest holder to interfere with or disturb the applicable EQT Subsidiary’s rights under such Real Property Agreement except in accordance with its terms while such EQT Subsidiary is not in default under the Real Property Agreement (other than a Permitted Encumbrance).  No applicable EQT Subsidiary is in default, and no circumstances exist which, if unremedied, would, either with or without notice or the passage of time or both, result in such default by such EQT Subsidiary under any of the Real Property Agreements to which such EQT Subsidiary is party; nor, to the Knowledge of Seller is any other party to any of the Real Property Agreements in default.

(d)           To the Knowledge of Seller, the zoning for all Real Property Interests permits the presently existing improvements and the continuation for the business presently being conducted thereon as a conforming use.  No EQT Subsidiary has received any notice of any violation of any applicable zoning ordinance or other Law relating to the operation of any business on any Real Property Interests.  To the Knowledge of Seller, there is no pending action before any Governmental Authority to change the zoning or building ordinances or any other Laws affecting the Real Property Interests.

(e)           Except as otherwise described in Section 2.4(c) and Section 2.4(d), an EQT Subsidiary holds hold Defensible Title to the Assets.

(f)            Except as set forth in Section 2.4(f) of the Disclosure Schedule and for the Dormant Pipeline, the tangible Assets, including the Real Property Interests, (i) are in good operating condition and repair, subject to ordinary wear and tear, and have been maintained in accordance with standard industry practice and (ii) are adequate for the purpose for which they are being used and are capable of being used without the need for repair or replacement except in the ordinary course of business.

(g)           The Assets being transferred to Buyer at the Closing include the assets (including all inventories of pipeline, valves, meters, cathodic protection equipment and related materials and supplies) and the properties, rights and entitlements (including rights of ways, easements, licenses and other real property rights) set forth on Exhibits A-1, A-2 and A-3.

(h)           The construction of the Ranger II NGL Pipeline by Seller is and has been performed in compliance with the Endangered Species Act of 1973 in respect of the Indiana bat species as described in the letter from the U.S. Fish and Wildlife Service to EQT dated February 10, 2010 (the “February 2010 Letter”).  The February 2010 Letter remains in full force and effect, and Seller has complied with its obligations thereunder.  To the Knowledge of Seller, the construction, as described in the February 2010 Letter, of the Ranger II NGL Pipeline by Buyer after the Closing will not be subject to delay based upon the presence of an

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Indiana bat critical habitat designated in accordance with 16 U.S.C. § 1533 within the area of the Ranger II NGL Pipeline.

(i)Each of the Ranger I NGL Pipeline and the Ranger II NGL Pipeline has been designed, installed, maintained and operated, as applicable, in compliance with the Department of Transportation requirements set forth in 49 C.F.R., Ch. 1, Part 195.

(j)Seller has undertaken the construction of the Ranger NGL Pipeline in accordance with the designs, plans, blueprints, as-built plans and specifications and system drawings and studies previously provided to Buyer.

Section 2.5.Absence of Certain Changes.  Since January 1, 2010, (a) no Seller Material Adverse Effect has occurred, (b) Seller has operated the Assets in the ordinary course of business, consistent with past practice, (c) Seller has not taken any action, or failed to take any action, that if taken or failed to be taken after the date hereof would result in a breach of Section 6.1, and (d) Seller has not engaged in any practice which would have the effect of (i) accelerating to periods before the Effective Time collection of revenues attributable to the Assets that would otherwise be expected (based on past practice) to be made in periods after the Effective Time, (ii) postponing to periods after the Effective Time payment of costs in respect of the Assets that would otherwise be expected (based on past practice) to be made in periods before the Effective Time.

Section 2.6.Litigation.  Except as set forth in Section 2.6 of the Disclosure Schedule, there is no material Proceeding pending or, to the Knowledge of Seller, threatened against Seller or in respect of the Assets or that would adversely affect, in any material respect, the transactions contemplated by this Agreement and the Other Transaction Documents.

Section 2.7.Compliance with Law.  Except with respect to Environmental Laws, which are addressed in Section 2.12, and any Laws related to Taxes, which are addressed in Section 2.11, Seller is in full compliance with all applicable material Law or order, writ, injunction or decree of any Governmental Authority that is applicable to the Assets.  No event has occurred or circumstance exists that (with or without notice or lapse of time), in respect of Seller’s ownership of the Assets that (a) may constitute or result in a violation by, or a failure to comply with, any material Law or order, writ, injunction or decree of any Governmental Authority that is applicable to the Assets or (b) may give rise to any obligation to undertake, or to bear all or any portion of the cost of, any material remedial action of any nature.  Seller has not received any notice or other communication (whether oral or written), in respect of Seller’s ownership of the Assets, from any Governmental Authority or any other Person regarding (i) any actual, alleged, possible, or potential violation of, or failure to comply with, any material Law, or (ii) any actual, alleged, possible, or potential obligation on the part of Seller to undertake, or to bear all or any portion of the cost of, any material remedial action of any nature.

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Section 2.8.Permits.

(a)All of the material permits, licenses, certificates, orders, approvals, authorizations, grants, consents, concessions, waivers, registrations, warrants, franchises or similar rights or privileges that are granted by a Governmental Authority and are necessary for, or are used or held for use in connection with, the ownership and operation of the Assets, including Environmental Permits (the “Permits”) are set forth on Exhibit A-4.

(b)All of the Permits set forth on Exhibit A-4 are in full force and effect.  Seller has timely filed applications for all permits required to operate the Assets as currently operated.

(c)Seller is not in violation of or default under any Permit that is material to, and used or held for use in connection with, the ownership and operation of the Assets, in the aggregate.

Section 2.9.Contracts.  Exhibit A-5 lists all Material Contracts, identified by the appropriate subcategories set forth in the definition of “Material Contract.”  Seller has performed its obligation under each Material Contract in all material respects and is not in material breach or default thereunder.  Seller has not waived any of its material rights under any of the Material Contracts or modified any of the material terms thereof.   To Seller’s Knowledge, no other Person that is party to a Material Contract is in material breach or default under any Material Contract. Each Material Contract is legal, valid, binding, in full force and effect and enforceable, except as enforceability may be limited by applicable bankruptcy, insolvency, fraudulent conveyance, reorganization or similar laws affecting creditors’ rights generally or by general equitable principles relating to enforceability.  Except as listed on Exhibit A-5 and for the Contracts entered into by the Parties at Closing, there are no Contracts with Seller or any of its Affiliates that will be binding on Buyer following the Closing.  No notice of default or breach has been received or delivered by Seller (or any of its Affiliates) under any Material Contract, the resolution of which is currently outstanding, and no currently effective notices have been received by Seller (or any of its Affiliates) of the exercise of any premature termination, price redetermination, market-out or curtailment of any Material Contract.

Section 2.10.Employees and Employee Benefit Matters.

(a)There does not exist, nor do any circumstances exist that could result in liability to Buyer (or its Affiliates) for any Taxes or other Liabilities (including any Controlled Group Liability) relating to any Benefit Plan sponsored, maintained or contributed to by Seller (or its Affiliates) or any trade or business whether or not incorporated, that together with Seller (or its Affiliates) would be a “single employer” as described in Section 414(b), (c), (m) or (o) of the Code.

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(b)On or prior to the date hereof, Seller shall provide Buyer with a schedule (the “Compensation Schedule”) that sets forth the names, titles, annual salaries, other compensation and date of hire of the employees of Seller (or its Affiliates) who spend all or substantially all of their business time engaged in, or in activities primarily related to, the operation or maintenance of the Assets (the “Operating Employees”).  None of the Operating Employees is obligated under any contract with Seller (or its Affiliates), nor subject to any judgment, decree or order of any court or administrative agency, that would prevent such Operating Employee from performing services for Buyer (or its Affiliates).  No Seller, nor any of its Affiliates, has received written notice from any Operating Employee or group of Operating Employees, that such Person or group intends to terminate employment and, to the Knowledge of Seller, no Operating Employee or group of Operating Employees intends to terminate employment.

(c)None of the Operating Employees is covered by any collective bargaining agreement and there are not any union organizing efforts underway with respect to any of the Operating Employees.

(d)There is no (i) judgment, order, decree or injunction involving Seller or its Affiliates with respect to any current or former Operating Employees or the terms and conditions of employment of any Operating Employee or (ii) Demand pending against or involving or, to the Knowledge of Seller, threatened against or involving, Seller or its Affiliates alleging violation of any state or federal employment laws with respect to the Operating Employees, including claims, actions, suits, investigations, audits or proceedings alleging employment discrimination, harassment, wrongful discharge, wage and hour violations, or any other unfair employment practices under applicable Law.

Section 2.11.Taxes.  Except as set forth in Section 2.11 of the Disclosure Schedule:

(a)All Tax Returns required to be filed by Seller have been duly and timely filed, and all Taxes due by Seller, whether or not shown to be due and owing on such Tax Returns, have been timely paid in full unless being contested in good faith and for which adequate reserves have been maintained on the books and records of Seller.

(b)None of the Tax Returns of Seller is the subject of any Tax audit or Tax examination by any Tax Authority, and there are no Demands for Taxes of Seller now pending or, to the Knowledge of Seller, threatened with respect to any Tax.

(c)There are no Liens or claims for Taxes (other than Taxes which are not yet due and payable) upon the Assets.

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(d)Seller is a “disregarded entity” as defined in Treas. Reg. Section 1.1445-2(b)(2)(iii) and is wholly-owned by EQT Gathering, Inc., a Pennsylvania corporation.

(e)With respect to Taxes other than income, franchise and similar Taxes, Seller has not executed or entered into with any Governmental Authority relating to any Asset any agreement, waiver or other document extending or having the effect of extending or waiving the period for assessment or collection of any Taxes that is still in effect.

(f)No claim has ever been made, or to Seller’s Knowledge, threatened by a Tax authority relating to the Assets in any jurisdiction where Seller has failed to file one or more Tax Returns asserting that Seller, or any of the Assets, is or may be subject to Taxes imposed by that jurisdiction.

Section 2.12.Environmental Matters.

(a)Except as set forth in Section 2.12(a) of the Disclosure Schedule, the Assets are not subject to, and with respect to the Assets, neither Seller nor its Affiliates have or are subject to, any material Environmental Liability.

(b)Except as set forth in Section 2.12(b) of the Disclosure Schedule, to the Knowledge of Seller, there are no facts, circumstances, or conditions existing, initiated or occurring prior to the Closing Date, which have or will result in any material Environmental Liability with respect to the Assets.

(c)Except as set forth in Section 2.12(c) of the Disclosure Schedule, neither the Seller nor its Affiliates are responsible for any Environmental Liability of any other person, whether by contract or, the Knowledge of Seller, by operation of law.

(d)Except as set forth in Section 2.12(d) of the Disclosure Schedule, the Assets and operations conducted by Seller and its Affiliates with respect to the Assets are and have been in compliance with the material requirements of all applicable Environmental Laws and Environmental Permits.

(e)Except as set forth in Section 2.12(e) of the Disclosure Schedule, Seller and its Affiliates have not received written inquiry or notice of any Demand since November 16, 2007, related to or arising under any Environmental Law relating to the Assets, except such Demands that have been fully and finally resolved without further liability to Seller or its Affiliates.

(f)Except as set forth in Section 2.12(f) of the Disclosure Schedule, none of Seller or its Affiliates is currently operating or required by any Governmental Authority to be operating any of the Assets under any compliance

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order, any consent decree or order, or corrective action decree or order issued by or entered into with any Governmental Authority under any Environmental Law.

(g)Seller has furnished Buyer copies of all environmental assessments, reports, audits and other material documents in its possession or under its control and dated on or after November 16, 2007 that relate to the environmental condition of the Assets or Seller’s or its Affiliate’s compliance with Environmental Laws with respect to the Assets.  To the Knowledge of Seller, any information Seller or its Affiliates have furnished to Buyer concerning the environmental condition of the Assets and the operations of Seller or its Affiliates related to compliance with Environmental Laws is accurate and complete.

Notwithstanding the generality of any other representations and warranties contained in this Agreement, except for Section 2.4(c), Section 2.8(a), Section 2.8(b) and Section 2.9, this Section 2.12 will be deemed to contain the only representations and warranties in this Agreement with respect to Environmental Liabilities, Environmental Permits or Environmental Laws.

Section 2.13.Intellectual Property.  To the Knowledge of Seller, (i) none of the Assets uses or incorporates any intellectual property that, or in a manner that, infringes or misappropriates the intellectual property of any third Person, and (ii) no third Person is infringing or misappropriating any intellectual property used or incorporated in any Asset.  To the Knowledge of Seller and except as set forth on Section 2.13 of the Disclosure Schedule, the Assets include all intellectual property required for their operation, free and clear of all Liens, and all such intellectual property will be available for use by Buyer in connection with the operation of the Assets immediately subsequent to the Closing on the same terms and conditions as available immediately prior to the Closing subject to any applicable license transfer requirements, all of which are set forth on Exhibit A-5-4 and, following execution by Buyer, the Propak license set forth on Exhibit A-5-3.  To the Knowledge of Seller, no trade secret or confidential know-how, either of which is material to the operation of any Asset, has been disclosed or authorized to be disclosed, other than pursuant to a non-disclosure agreement that protects the proprietary interests in and to such trade secrets and confidential know-how.

Section 2.14.Condemnation.  There are no pending or threatened condemnation or eminent domain proceedings, lawsuits or administrative actions or contemplated sales in lieu thereof, involving a partial or total taking of any of the Assets.

Section 2.15.Bonds, Letters of Credit, Guarantees.  There exist no bonds, letters of credit and guarantees posted by Seller or any Affiliate of Seller with any Governmental Authority or third Person relating to the Assets.

Section 2.16.Brokers; Finders and Fees.  Neither Seller nor any of its Affiliates has employed any investment banker, broker or finder or incurred any liability for any investment banking, financial advisory or brokerage fees, commissions or finders’ fees in connection with

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this Agreement or the Other Transaction Documents or the transactions contemplated hereby and thereby.

ARTICLE III
DISCLAIMER OF REPRESENTATIONS AND WARRANTIES

EXCEPT AS SPECIFICALLY SET FORTH IN ARTICLE II, SELLER MAKES NO REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, AT LAW OR IN EQUITY, IN RESPECT OF OR OTHERWISE IN ANY WAY RELATING TO ITSELF OR THE ASSETS, INCLUDING WITH RESPECT TO MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE, AND ANY SUCH OTHER REPRESENTATIONS OR WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED, AND, EXCEPT AS SET FORTH IN THIS AGREEMENT, BUYER SHALL BE DEEMED TO BE TAKING THE ASSETS “AS IS” AND “WHERE IS” FOR ALL PURPOSES.  BUYER FURTHER ACKNOWLEDGES THAT, EXCEPT AS EXPRESSLY REPRESENTED OTHERWISE IN THIS AGREEMENT  SELLER HAS NOT AND WILL NOT MAKE ANY REPRESENTATION OR WARRANTY REGARDING ANY MATTER OR CIRCUMSTANCE RELATING TO ENVIRONMENTAL LAWS, ENVIRONMENTAL LIABILITIES, ENVIRONMENTAL PERMITS, OR THE PROTECTION OF HUMAN HEALTH, SAFETY, NATURAL RESOURCES OR THE ENVIRONMENT AS PERTAINS TO THE ASSETS.

ARTICLE IV
REPRESENTATIONS AND WARRANTIES OF BUYER

Buyer hereby represents and warrants to Seller as follows:

Section 4.1.Organization; Etc.  Buyer (a) is a limited liability company duly formed, validly existing and in good standing under the laws of the State of Delaware, (b) has all requisite power and authority to own, lease and operate all of its properties and assets and to carry on its business substantially as now being conducted, and (c) is duly qualified and in good standing to do business in each jurisdiction in which the nature of its business or the ownership, operation or leasing of its properties makes such qualification necessary, except in the case of clause (c) where the failure to be so qualified and in good standing would not, individually or in the aggregate, have a Buyer Material Adverse Effect.  As used in this Agreement, the term “Buyer Material Adverse Effect” shall mean an event, change or circumstance which would adversely affect in a material respect the ability of Buyer to consummate the transactions contemplated hereby.

Section 4.2.Authority Relative to this Agreement and the Other Transaction Documents.  Buyer has all requisite limited liability company power, authority and capacity to execute and deliver this Agreement and the Other Transaction Documents and to consummate the transactions contemplated hereby and thereby.  The execution and delivery of this Agreement and the Other Transaction Documents and the consummation of the transactions contemplated hereby and thereby have been or will be, as applicable, duly and validly authorized by all

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requisite limited liability company action on the part of Buyer.  This Agreement has been, and the Other Transaction Documents will be, duly and validly executed and delivered by Buyer and, assuming this Agreement has been, and the Other Transaction Documents to which Seller is a party will be, duly authorized, executed and delivered by Seller, constitutes or will constitute, as applicable, a valid and binding agreement of Buyer, enforceable against Buyer in accordance with its terms, except that (a) such enforcement may be subject to any bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer or other laws, now or hereafter in effect, relating to or limiting creditors’ rights generally and (b) enforcement of this Agreement and the Other Transaction Documents, including, among other things, the remedy of specific performance and injunctive and other forms of equitable relief, may be subject to equitable defenses and to the discretion of the court before which any proceeding therefor may be brought.

Section 4.3.Absence of Conflicts.  The execution and delivery of this Agreement and the Other Transaction Documents by Buyer and the consummation by Buyer of the transactions contemplated hereby and thereby do not and will not (a) conflict with or result in any breach of any provision of the certificate of formation, limited liability company agreement or other organizational documents of Buyer, (b) result in a violation or breach of, or constitute (with or without due notice or lapse of time or both) a default (or give rise to any right of termination, cancellation or acceleration) under, or require any Consent under, any indenture, license, contract, agreement or other instrument or obligation to which Buyer or any of its Affiliates is a party or by which any of them or any of their respective properties or assets may be bound, (c) violate any material order, writ, injunction, decree or Laws applicable to Buyer, any of its Affiliates or any of their respective properties or assets, or (d) require any filing with, or the obtaining of any permit, authorization, Consent or approval of, any Governmental Authority that has not been made or obtained, except in the case of (d) of this Section 4.3 for any such matters which, individually or in the aggregate, would not have a Buyer Material Adverse Effect.

Section 4.4.Availability of Funds.  Buyer has sufficient immediately available funds in cash or cash equivalents to pay the Estimated Purchase Price and to pay any other amounts payable pursuant to this Agreement and to effect the transactions contemplated hereby.

Section 4.5.Litigation.  There is no Proceeding pending or, to the Knowledge of Buyer, threatened against Buyer or any of its Affiliates which, individually or in the aggregate, would have a Buyer Material Adverse Effect.

Section 4.6.Brokers; Finders and Fees.  Neither Buyer nor any of its Affiliates has employed any investment banker, broker or finder or incurred any liability for any investment banking, financial advisory or brokerage fees, commissions or finders’ fees in connection with this Agreement or the Other Transaction Documents or the transactions contemplated hereby or thereby.

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ARTICLE V
TAX MATTERS

Section 5.1.Preparation of Tax Returns.  Seller shall prepare and file (or cause to be prepared and filed) all Tax Returns with respect to the Assets for all Pre-Closing Periods and Straddle Periods that are required to be filed after the Closing Date, and shall pay (or cause to be paid) all Taxes due with respect to the Assets for all Pre-Closing Periods and Straddle Periods (whether or not such Taxes are required to be shown on a Tax Return).  Buyer shall promptly pay to Seller the portion of such Tax for which Buyer is responsible pursuant to Section 5.2 within five days of receipt of notice therefor.

Section 5.2.Responsibility for Taxes.  Seller shall be responsible for and entitled to all refunds of, and shall indemnify Buyer Indemnitees from and against, all Taxes with respect to the Assets for any Pre-Closing Period and for that portion of any Straddle Period that ends on the Closing Date.  Buyer shall be responsible for the remaining Straddle Period Taxes that begins on the day after the Closing and ends on the last day of the Straddle Period.  For this purpose, Straddle Period Taxes shall be (a) allocated on an interim closing of the books method for income and franchise Taxes, and (b) prorated on a daily basis to the Closing date and thereafter for all other Taxes.  Notwithstanding anything to the contrary herein, any ad valorem or property Taxes paid or payable with respect to the Assets shall be allocated to the Tax period applicable to the ownership of the Assets regardless of when such Taxes are assessed.

Section 5.3.Post-Closing Assistance.  Seller and Buyer will each provide the other such reasonable assistance, at the sole cost and expense of the requesting party, as may reasonably be requested in connection with the preparation of any Tax Return with respect to the Assets, or any audit or other examination by any Tax Authority or any judicial or administrative proceedings relating to Taxes with respect to the Assets, and each will retain and provide the requesting Party with any records or information that may be reasonably relevant to such return, audit or examination, proceedings or determination.  The Party requesting assistance will reimburse the other Party for reasonable out-of-pocket expenses (other than salaries or wages of any employees of the Parties) incurred in providing such assistance.  Buyer agrees, at its sole cost and expense, to file an Application for Energy Direct Pay Authorization and Kentucky Sales and Use Tax Energy Exemption Annual Return with the Kentucky Department of Revenue to qualify for the exemption of sales or use Tax on Buyer’s purchases of energy following the Closing, and to include any benefit from such reduction in sales Tax in all applicable electricity allocations to Seller pursuant to the Big Sandy Shared Services Agreement.

Section 5.4.Conduct of Business.

(a)From and after the applicable Closing Date, each of Buyer and Seller (the “Tax Indemnified Person”), shall notify the chief tax officer (and the notice party as set forth in Section 10.4 of this Agreement) of the other Party (the “Tax Indemnifying Person”), in writing within 15 days of receipt by the Tax Indemnified Person of written notice of any pending or threatened audits, adjustments, claims, examinations, assessments or other proceedings (a “Tax Audit”) which may affect the liability for Taxes of such other Party.  If the Tax Indemnified Person fails to give such timely notice to the other Party, it shall not

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be entitled to indemnification for any Taxes arising in connection with such Tax Audit if such failure to give notice materially adversely affects the other Party’s right to participate or meaningfully defend in the Tax Audit.

(b)If a Tax Audit relates to Taxes for which only Seller would be liable to indemnify Buyer under this Agreement, Seller shall have the option, at its expense, to control the defense and settlement of such Tax Audit.  If Seller does not elect to control the defense and settlement of such Tax Audit by giving written notice of to Buyer within 15 days of the receipt of the first notice of such audit (and failure to give such timely notice shall constitute a waiver of seller’s right to elect not to control and defend the audit), Buyer may, at Buyer’s expense, control the defense and settlement of such Tax Audit, provided that Seller shall pay any Tax for which it is otherwise liable under Section 5.2.  If such Tax Audit relates solely to Taxes for which only Buyer would be liable under this Agreement, Buyer shall, at its expense, control the defense and settlement of such Tax Audit to the extent that such Tax Audit relates to Taxes for which Buyer is liable to indemnify Seller under Section 5.2.

(c)If a Tax Audit relates to Taxes for which both Seller and Buyer could be liable under this Agreement, to the extent practicable, the items of income, gain, loss, deduction and credit or other item required to be reported on or otherwise reported on the applicable Tax Return (“Tax Items”) with respect to such Tax Audit will be distinguished and each Party will have the option to control the defense and settlement of those Taxes for which it is so liable.  If such Tax Audit relates to a Straddle Period and any Tax Item cannot be identified as being a liability of only one Party or cannot be separated from a Tax Item for which the other Party is liable, Seller, at its expense, shall have the option to control the defense and settlement of the Tax Audit, provided that such Party defends the items as reported on the relevant Tax Return and provided further that no such matter shall be settled without the written consent of Buyer, not to be unreasonably withheld.

(d)Any Party whose liability for Taxes may be affected by a Tax Audit shall be entitled to participate at its expense in such defense and to employ counsel of its choice at its expense and shall have the right to consent to any settlement of such Tax Audit (not to be unreasonably withheld) to the extent that such settlement would have an adverse effect with respect to a period for which that Party is liable for Taxes, under this Agreement or otherwise.

Section 5.5.Pre- and Post-Closing Actions.  Except to the extent required by applicable Laws, Seller shall not and shall not permit its affiliates to take any action (including the amendment of any Tax Return) on or before the Closing Date which could reasonably be expected to materially increase Buyer’s liability for Taxes (including any liability of Buyer to indemnify Seller for Taxes under this Agreement).  Except to the extent required by applicable

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Laws, Buyer shall not and shall not permit its affiliates to take any action (including the amendment of any Tax Return) on or after the Closing Date which could reasonably be expected to materially increase Seller’s liability for Taxes (including any liability of Seller to indemnify Buyer for Taxes under this Agreement).

Section 5.6.Refunds of Certain Taxes Received by Buyer.  Buyer agrees to pay to Sellers any refund received (whether by payment, credit, offset or otherwise, and together with any interest thereon) after the Closing Date by Buyer or its affiliates that is entitled to be paid to Seller pursuant to Section 5.2.  Buyer shall cooperate with Seller and Seller’s affiliates at Seller’s sole expense in order to take all necessary steps to claim any such refund.  Any such refund received by Buyer or its affiliates shall be paid to Seller within 30 days after such refund is received.   Buyer agrees promptly furnish to Seller all information, records and assistance necessary to verify the amount of the refund or overpayment. Buyer shall have no affirmative duty to identify any refunds that might be due and payable to Seller under this Section 5.6.

Section 5.7.Like-Kind Tax Exchange.  The Parties hereby agree that any Party, at its sole expense, may elect a like-kind exchange under Section 1031 of the Code with respect to the transactions contemplated by this Agreement.  Seller, at its expense, shall have the right at any time prior to the Closing to assign all or a portion of its rights under this Agreement to a “qualified intermediary” (as that term is defined in Treasury Regulations Section 1.1031(k)-1(g)(4)(iii)) or an “exchange accommodation titleholder” (as that term is defined in Revenue Procedure 2000-37, 2000-2 C.B. 308) in order to effectuate the transactions contemplated hereby at such Closing in a manner that will qualify, either in whole or in part, as a like-kind exchange under Section 1031 of the Code.  Likewise, Buyer, at its expense, shall have the right at any time prior to the Closing to assign all or a portion of its rights under this Agreement to a qualified intermediary or an exchange accommodation titleholder for the same purpose.  In the event that any Party assigns its rights under this Agreement pursuant to this Section 5.7, such Party agrees to notify the other Party in writing of such assignment on or before the Closing attributable to such rights.  The Parties agree to cooperate to the extent reasonably requested by the other Parties in order to effectuate the transactions contemplated hereby as a like-kind exchange under Section 1031 of the Code.  The Parties acknowledge and agree that any assignment of rights under this Agreement to a qualified intermediary or an exchange accommodation titleholder shall not release any Party from any of its liabilities and obligations to the other Party under this Agreement, and that neither Party represents to the other Party that any particular Tax treatment will be given to any Party as a result thereof.  In no event will any Party be liable to the other for any failure of any  transaction to qualify for like-kind treatment under Section 1031 of the Code.

Section 5.8.Transfer Taxes.  Any sales, use, recording or other transfer taxes (“Transfer Taxes”) imposed on the purchase and sale of the Assets pursuant to this Agreement (including any interest, penalties, or additions to tax with respect thereto) shall be paid 50% by Seller and 50% by Buyer.  The Parties shall reasonably cooperate in good faith to minimize, to the extent permissible under applicable Law, the amount of any Transfer Taxes described in this Section 5.8.

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ARTICLE VI
ADDITIONAL COVENANTS

Section 6.1.Conduct of Business.  Except as contemplated by the covenants to be performed by Seller prior to the Closing under this Agreement or as set forth in Section 6.1 and Section 6.8 of the Disclosure Schedule or as consented to in writing by Buyer, such consent not to be unreasonably withheld, delayed or conditioned, prior to the Closing, Seller covenants and agrees (and agrees to cause each of its Affiliates that it controls) to (i) operate its business with respect to the Assets in the ordinary course of business consistent with past practices and (ii) use commercially reasonable efforts to keep available the services of the current officers, key employees and consultants related to the Assets and, without limiting the generality of the preceding, Seller shall not, (and shall not permit any of its Affiliates to) directly or indirectly do, or agree to do, any of the following:

(a)sell, transfer, assign, convey, abandon or otherwise dispose of any of the Assets, except for (i) sales or dispositions individually not exceeding $10,000 individually or $25,000 in the aggregate and (ii) sales or dispositions of inventory or obsolete equipment in the ordinary course of business;

(b)make any commitment or enter into any agreement with respect to any capital project relating to any Asset in excess of $100,000 individually or $250,000 in the aggregate that would become an Assumed Liability;

(c)enter into, terminate, amend, waive or permit to lapse (prior to its applicable expiration date) in any material respect any Permit, Contract, or instrument creating a Real Property Interest that is or would be an Asset conveyed to Buyer by Seller at the Closing or that would affect any such Asset, other than in the ordinary course of business;

(d)create or permit the creation of any Lien on any Asset (other than Permitted Encumbrances) or cancel any material debts or settle, discharge or waive any material claims or rights pertaining to the Assets;

(e)grant or create any preferential right to purchase, right of first opportunity or other transfer restriction or requirement with respect to any Asset;

(f)make, amend or revoke any material election with respect to any material Taxes relating to the Assets that would materially and adversely impact Buyer;

(g)fail to maintain in effect insurance of such types, covering such risks and with amounts and deductibles as are in place on the date of this Agreement solely with respect to the Assets; or

(h)agree, whether in writing or otherwise, to do any of the foregoing.

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Section 6.2.Access to Records and Assets; Access Indemnity and Confidentiality.

(a)During the period from the date hereof through the Closing, Seller shall (and shall cause its Affiliates that it controls to) at reasonable times and upon reasonable notice (i) make all the books and records relating to the Assets (including the Records) available to Buyer and its authorized representatives for examination as Buyer may request, (ii) permit Buyer to make such copies and inspections thereof, upon reasonable advance notice and during regular business hours, as Buyer may reasonably request, and (iii) permit Buyer and its authorized representatives to consult with employees, officers, directors, accountants, consultants, legal counsel and other authorized representatives of Seller and to conduct, at Buyer’s sole cost, expense and risk, inspections and site visits of the Assets; provided, however, that none of Buyer and its authorized representatives shall have any right of access to (A) any proprietary data that relates to another business of Seller and is not used in connection with the ownership, use, operation or maintenance of the Assets, (B) confidential information subject to a third party confidentiality agreement, or (C) any such information which, if disclosed, would violate an attorney-client privilege or applicable Law.  Buyer and its authorized representatives shall comply in all material respects with all rules, regulations, policies and instructions issued by Seller or any third Person operator regarding any of Buyer’s or its authorized representatives’ actions prior to Closing while upon, entering or leaving any property included in the Assets.

(b)BUYER SHALL PROTECT, DEFEND, INDEMNIFY AND HOLD SELLER HARMLESS FROM AND AGAINST ANY AND ALL LOSSES OCCURRING ON OR TO THE ASSETS OR TO THE PERSON OR PROPERTY OF ANY PERSON ARISING FROM OR CAUSED BY THE ACTS OR OMISSIONS OF SELLER, ITS AFFILIATES’ OR ANY OTHER PERSON ACTING ON SELLER’S OR ITS AFFILIATES’ BEHALF IN CONNECTION WITH THE ACCESS RIGHTS UNDER SECTION 6.2(A), EXCEPT FOR INSTANCES OF GROSS NEGLIGENCE OR WILLFUL MISCONDUCT ON THE PART OF SELLER, ITS AFFILIATES OR ANY OTHER PERSON ACTING ON THEIR RESPECTIVE BEHALF; PROVIDED, HOWEVER, THAT THE FOREGOING OBLIGATION OF BUYER SHALL NOT APPLY WITH RESPECT TO ANY ENVIRONMENTAL LIABILITY TO THE EXTENT EXISTING PRIOR TO SUCH ACCESS AND THAT ARE DISCOVERED DURING OR IN CONNECTION WITH SUCH ACCESS.

(c)Until the Closing, Buyer shall (and shall cause its Affiliates and authorized representatives to) hold in confidence all information and data furnished to it (or its Affiliates or representatives) pursuant to this Section 6.2 in accordance with Section 6.14.

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Section 6.3.Regulatory Filings and Consents.  From the date hereof until the Closing:

(a)Subject to Seller’s and Buyer’s additional obligations in clauses (b), (c) and (d) of this Section 6.3, Seller and Buyer shall use commercially reasonable efforts to (i) take, or cause to be taken, all actions, and do, or cause to be done, all things that, in either case, are necessary, proper or advisable under Law or otherwise to consummate and make effective the transactions contemplated by this Agreement, including to do or cause the conditions set forth in ARTICLE VII to be satisfied and to obtain prior to Closing all Consents to the transfer and assignment of the Assets that are required under this Agreement, and (ii) obtain from the relevant Governmental Authorities all Authorizations required to be obtained at or prior to the Closing by Buyer or Seller in connection with the authorization, execution, delivery and performance of this Agreement and the consummation of the transactions contemplated hereby; provided, however, that Seller and its Affiliates shall not be required to make any material monetary expenditure, commence or be a plaintiff in any material litigation or offer or grant any material accommodation (financial or otherwise) to any Person.

(b)As promptly as practicable after the date hereof, Seller and Buyer shall make all necessary filings, including filings under the HSR Act and any other Antitrust Law, request early termination thereunder, and thereafter make any other required submissions, with respect to this Agreement and the transactions contemplated hereby required under any Law at or prior to the Closing.  The Parties shall bear the costs and expenses of their respective filings; provided that **.  The Parties shall cooperate in connection with the making of all such filings, including by providing copies of all such documents to the nonfiling Party and its advisors prior to filing and, if requested, accepting all reasonable additions, deletions or changes suggested in connection therewith.  The Parties shall each use best efforts to furnish or cause to be furnished all information required for any application or other filing to be made pursuant to any Law in connection with the transactions contemplated by this Agreement.

(c)The Parties shall each give prompt notice to the other of the receipt of any notice or other communication (in each case whether oral or written) from (i) any Person alleging that the Consent of such Person is or may be required in connection with the transactions contemplated hereby, (ii) any Governmental Authority in connection with the transactions contemplated hereby, (iii) any Governmental Authority or other Person regarding the initiation or threat of initiation of any claims, actions, suits, proceedings, arbitrations or investigations against, relating to, or involving or otherwise affecting Buyer or Seller that relate to the consummation of the transactions contemplated hereby, and (iv) any Person regarding the occurrence or nonoccurrence of any event the occurrence or nonoccurrence of which would be reasonably likely to (A) cause any condition to

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the obligations of the other Party to consummate the transactions contemplated hereby not to be satisfied, (B) cause a breach of the representations, warranties or covenants of such Party under this Agreement, or (C) delay or impede the ability of either Buyer or Seller, respectively, to consummate the transactions contemplated by this Agreement or to fulfill their respective obligations set forth herein.  No delivery of any notice pursuant to clause (iv) of this Section 6.3(c) shall cure any breach of any representation, warranty or covenant of the Party hereto giving such notice contained in this Agreement.

(d)Each Party agrees to use commercially reasonable efforts to contest and to resist any action, including administrative or judicial action, and to have vacated, lifted, reversed or overturned any order (whether temporary, preliminary or permanent) of any court or other Governmental Authority that is in effect and that restricts, prevents or prohibits the consummation of the transactions contemplated by this Agreement, including the reasonable pursuit of all available avenues of administrative and judicial appeal, and each Party agrees to provide reasonable cooperation to the other Party in connection with the foregoing.  Notwithstanding the foregoing, Buyer shall not be required to take any commercially unreasonable action that substantially impairs the overall benefits realized from the consummation of the transactions set forth herein, and in no event shall Buyer be required to (i) sell, hold separate or otherwise dispose of the Assets or Buyer’s or its Affiliate’s other assets or businesses now owned or hereafter acquired by Buyer to resolve any objection or proceeding objecting to the transactions contemplated hereunder or (ii) terminate any existing relationships and contractual rights and obligations.  Buyer shall be entitled to direct any proceedings or negotiations with any Governmental Authority or other Person relating to the foregoing, provided that it shall afford Seller a reasonable opportunity to participate therein.  Neither Party shall take any action that could reasonably be expected to materially hinder or delay the granting of any Authorization necessary for the consummation of the transactions contemplated hereby.

Section 6.4.Cooperation; Further Assurances.

(a)In the event that at any time after the Closing any further action is necessary to carry out the purposes of this Agreement, the Parties hereto shall take such further action (including the execution and delivery of such further documents and instruments) as any Party hereto may reasonably request, all at the sole expense of the requesting Party (unless the action requested should have been taken prior to the Closing, in which case the Party or Parties that would have borne the expense of taking such action had it been taken prior to the Closing shall bear such expense).  Without limiting the generality of the foregoing, the Parties hereto will take all reasonably requested actions to ensure that (i) the

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Assets are, except as otherwise contemplated hereby, transferred to Buyer, and (ii) that all other assets otherwise used by Seller, are owned by Seller.

(b)For the longer period of (i) seven years after the Closing Date, (ii) as required by the terms of the applicable Assigned Contract or (iii) as required by Law, Buyer agrees to retain the originals of the Records at its sole cost and expense.  Seller may retain a copy of the Records to the extent such Records pertain to its obligations under this Agreement.

Section 6.5.Operating Employees.

(a)From and after the date hereof, Buyer shall offer, or cause an Affiliate to offer, employment to all of the Operating Employees on such terms and conditions of employment that would apply to similarly situated employees of Buyer (or its Affiliate); provided, however, that the terms and conditions of each such offer of employment shall **.  For each Operating Employee who accepts employment by Buyer (or any of its Affiliates) (the “Hired Employees”) (a) Buyer (or its Affiliate, if applicable) shall credit years of service with Seller (or any of its Affiliates) (as determined from the date of hire for such Operating Employee set forth in the Compensation Schedule) for purposes of determining eligibility, vesting and benefit accrual (excluding any benefit accrual under any Benefit Plans that is a defined benefit pension plan) under any Benefit Plans of Buyer (or its Affiliate, if applicable) currently in place or later adopted; provided, however, in order to prevent duplicative credit for vacation time, Buyer shall not be required to credit vacation for the calendar year of hire to the extent that the Hired Employee has used or been paid for such vacation time by Seller or any of its Affiliates, and (b) Buyer shall (or shall cause its Affiliate to) waive any pre-existing condition limitation and eligibility waiting period under any Benefit Plan that is a group health plan in which any such Hired Employees are eligible to participate following the Closing, and **.  Buyer shall notify Seller of any acceptances of such offers by the Operating Employees.

(b)The provisions of this Section 6.5 are intended for the sole benefit of the Parties and shall not inure to the benefit of any other Person (other than permitted assigns of the Parties hereto) either as a third party beneficiary or otherwise.

(c)Seller shall pay the Hired Employees their accrued and unused vacation through the Closing Date on the Closing Date.

(d)Seller shall be exclusively responsible for complying with COBRA with respect to the Hired Employees and their qualified beneficiaries by reason of any such employees’ termination of employment with Seller, and Buyer shall not

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have any obligation or liability to provide rights under COBRA on account of any such termination of employment.

(e)Without limiting the foregoing, **.

Section 6.6.Public Announcement.  Neither Party, nor any of their respective Affiliates, shall make any press release or other public announcement regarding the existence of this Agreement, the contents hereof (including the Purchase Price) or the transactions contemplated hereby without the prior written consent of the other Party (which consent shall not be unreasonably withheld or delayed); provided, however, that the foregoing shall not restrict disclosures to the extent (a) necessary for a Party to perform this Agreement (including disclosure to a Governmental Authority or any third Persons holding rights of Consent or other rights that may be applicable to the transactions contemplated by this Agreement, as reasonably necessary to seek such Consents or provide notices, seek waivers, amendments or termination of such other rights), (b) required (upon advice of counsel) by applicable securities or other applicable Laws or regulations or the applicable rules of any stock exchange having jurisdiction over the Parties or their respective Affiliates or (c) subject to Section 6.14, such Party has given the other Party a reasonable opportunity to review such disclosure prior to its release and no objection is raised; and provided further that, in the case of clauses (a) and (b), to the extent permitted by applicable Law, each Party shall use its commercially reasonable efforts to consult with the other Party regarding the contents of any such release or announcement prior to making such release or announcement.

Section 6.7.Insurance.

(a)The Parties hereto acknowledge that Seller maintains a program of property and liability insurance coverage in respect of the Assets.  All of the insurance policies through which the program of coverage is presently or has previously been provided by or to Seller or its Affiliates are herein referred to collectively as the “Seller Policies.”  It is understood and agreed by Buyer that from and after the Closing:

(i)no insurance coverage shall be provided under Seller Policies to Buyer; and

(ii)no claims regarding any matter whatsoever, whether or not arising from events occurring prior to the Closing, shall be made by Buyer against or with respect to any of Seller Policies, regardless of their date of issuance unless directed by Seller and for Seller’s benefit.

(b)Buyer shall procure, pay for and maintain in effect its own policies of insurance with respect to the Assets and shall indemnify and defend Seller and its Affiliates against, and shall hold them harmless from any liability, demands, claims, actions or causes of action, assessments, losses, damages, costs and

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expenses arising out of claims made after the Closing against any of Seller Policies by Buyer, any of Buyer’s Affiliates or any other Person claiming to be subrogated to Buyer’s or any of its Affiliates’ rights.  Such indemnity shall cover, without limitation, any claim by an insurer for reinsurance, retrospective premium payments, prospective premium increases or any other restitution or funding requirements attributable to any such claim or policy requirements.

Section 6.8.Purchase Orders.  From and after the Closing, Buyer shall complete the purchase of the equipment, and pay the outstanding amounts payable under, the purchase orders set forth in Section 6.8 of the Disclosure Schedule, which are part of the Contracts assumed by Buyer hereunder.

Section 6.9.Disclosure Schedules.  Any information furnished in ARTICLE II of the Disclosure Schedule shall be deemed to modify all of the representations and warranties of Seller set forth in ARTICLE II for which the applicability of such information and disclosure is readily apparent.  The inclusion of any information on the Disclosure Schedule shall not be deemed to be an admission or acknowledgment, in and of itself, that such information is required by the terms hereof to be disclosed, is material to the Assets or Seller or has or would have a Seller Material Adverse Effect.

Section 6.10.Nuisance Litigation.  From and after the date hereof, Seller agrees to use reasonable best efforts to actively defend the matter described in subsection (2) of Section 2.6 of the Disclosure Schedule (the “Nuisance Proceeding”).  Seller shall not agree to any settlement, compromise or consent of the Nuisance Proceeding without the prior written consent of Buyer, which consent may not be unreasonably withheld, delayed or conditioned; provided, however that Buyer’s consent will not be required if such settlement, compromise or consent includes an unconditional written release of Buyer from all further liability in respect of such claim and could not reasonably be expected to materially and adversely affect Buyer’s operation of the Assets following the Closing.  Buyer agrees to provide such cooperation as reasonably requested by Seller in connection with the foregoing.

Section 6.11.Langley Plant Environmental Matters.

(a)Prior to and until the Closing, Seller agrees that it will not undertake any activities related to Langley Plant Environmental Matters, including **, including **

(b)At the Closing, Buyer shall assume all responsibility for Langley Plant Environmental Matters, **, subject to Buyer’s right of indemnity provided in Section 9.2.

Section 6.12.Transition Plan.

(a)Without limiting Section 6.4, for a period of 120 days following the Closing, each Party agrees to offer reasonable assistance to the other Party,

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upon such other Party’s written request, for the purpose of transitioning ownership and operation of the Assets from Seller to Buyer.  In connection with any services provided under this Section 6.12, each month following the commencement of such services, the Party requesting such limited transition services shall pay the Party providing such services an amount equal to ** all ** reasonable out-of-pocket or third-party costs incurred by such Party and its Affiliates in providing the services contemplated by this Section 6.12.

(b)Until the earlier to occur of (i) 90 days following the Closing Date, or (ii) in the case of those software and application licenses referenced below, the date on which Buyer acquires a separate license or adequate replacement system, Seller will (x) cooperate with and assist in Buyer’s efforts to obtain a separate license (or an adequate replacement system) for each of the software and applications set forth on Section 2.13 of the Disclosure Schedule (each a “Transition IT System”) and (y) continue to host such Transition IT System following the Closing for the benefit of Buyer.  Notwithstanding the foregoing, Buyer acknowledges that in the case of each Transition IT System licensed to Seller or its Affiliates, the consent of the licensor of such Transition IT System may be required to provide Buyer any use or access to such Transition IT System, and Seller’s obligations under this Agreement are limited to providing assistance reasonably requested by Buyer to obtain such consent in consideration of the payments described in clause (a) of this Section 6.12.  The failure to obtain such consent shall not be a breach of this Agreement.  Any costs or fees to obtain such consent shall be borne by Buyer.

(c)Commencing on the date hereof, Buyer shall exercise commercially reasonable efforts to obtain, within 90 days following the Closing, the necessary master agreements (the “Buyer Master Agreements”) in respect of all Assigned Contracts that are purchase orders (the “Assigned Purchase Orders”) under master agreements retained by Seller (the “Retained Master Agreements”).  As of and from the Closing until the earlier of 90 days following Closing Date or such time as Buyer has entered into the relevant Buyer Master Agreement, Seller shall, to the extent permitted by applicable Law and by the terms of the Retained Master Agreement for the Assigned Purchase Orders for which Buyer has not yet entered into a Buyer Master Agreement, hold such Retained Master Agreement for the benefit and burden of Buyer and the covenants and obligations thereunder related to any Assigned Purchase Order shall be fully performed by Buyer and all rights and Liabilities existing thereunder related to any Assigned Purchase Order shall be for Buyer’s account.  Buyer shall pay Seller an amount equal to all reasonable out-of-pocket or third-party costs incurred by Seller under this Section 6.12(c).  Seller makes no representations or warranties regarding Buyer’s ability to obtain the Buyer Master Agreements, and Seller shall have no liability by reason of it’s efforts to hold the Retained Master Agreements for the benefit and burden of Buyer pursuant to this Section 6.12(c).

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(d)Following the date hereof, Seller will continue to exercise commercially reasonable efforts to obtain the consent of Propak Systems, Ltd. (“Propak”) to Buyer’s proposed revisions to the Propak License Agreement to be executed and delivered by Buyer and Propak on the Closing Date.

Section 6.13.Expansion Plans.  The Parties shall cooperate in good faith regarding the location of the future expansion of Seller’s Affiliates’ compression equipment included in the Excluded Assets to add additional compression reasonably required to fully utilize the designated capacity of the Big Sandy Pipeline (the “Big Sandy Compression Expansion”) and for Buyer’s expansion of the Processing Facilities following the Closing to include a 60 MMcf cryogenic gas processing plant (the “Langley Plant 3”), as well as with respect to future expansions of the Processing Facilities and Big Sandy Pipeline.  Following the date hereof, the Parties will select and engage the services of a mutually agreeable engineering firm (the “Engineering Firm”) to prepare plans (the “Langley Site Development Plans”) that identify the location of the Big Sandy Compression Expansion and the Langley Plant 3 on the site of the Processing Facilities, including all supply, discharge and any utility lines with respect thereto, as well as the interconnection of the Processing Facilities and the Big Sandy Compression Expansion.  Both Parties will participate and consult with the Engineering Firm for the purpose of ensuring that, to the extent possible, the Langley Site Development Plans, as well as any anticipated future expansions of the Processing Facilities and the Big Sandy Pipeline (e.g., by adding an additional residue gas line), utilize available space on the site of the Processing Facilities to accommodate Langley Plant 3, the Big Sandy Compression Expansion, and such anticipated future expansions of the Processing Facilities and the Big Sandy Pipeline.  The Parties shall use commercially reasonable efforts to cause the Engineering Firm to complete the Langley Site Development Plans within 120 days of the date hereof.  The Parties will each bear 50% of the cost of the Engineering Firm.  After the Closing, the Parties agree to amend the Conveyance to specify the location and extent of Seller’s retained easement for purposes of accessing, operating and expanding the Big Sandy Pipeline compression included in the Excluded Assets.

Section 6.14.Confidentiality.

(a)Buyer and its Affiliates shall not disclose, directly or indirectly, any documents, work papers or other materials of a confidential or proprietary nature related to Seller or the Assets (including, without limitation, any information obtained in connection with the entering into of this Agreement) and shall have all such information kept confidential; provided, however, that Buyer may disclose any such information (A) that is or becomes generally available to the public other than as a result of disclosure by Buyer or its Affiliates, (B) that is or becomes available to Buyer on a non-confidential basis from a source that is not bound by a confidentiality obligation to Seller or its Affiliates, (C) to Buyer’s financial advisors, consultants, attorneys and banks or (D) with the prior written approval of Seller, which approval shall not be unreasonably withheld or delayed; provided, further, that to the extent that Buyer or its Affiliates may become legally

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compelled to disclose any such information by any Governmental Authority or if Buyer or its Affiliates receives an opinion of counsel that disclosure is required in order to avoid violating any laws, Buyer or its Affiliates may disclose such information but only after, if applicable or relevant, they have used all commercially reasonable efforts to afford Seller, at its sole cost and expense, the opportunity to obtain an appropriate protective order, or other satisfactory assurance of confidential treatment, for the information required to be disclosed; provided, further, that Buyer may disclose such information to the extent necessary to comply with applicable Law, or to enforce its rights and obligations under this Agreement; provided, further, that after the Closing, this Section 6.14(a) shall not prohibit or restrict or otherwise limit the use or disclosure by Buyer and its Affiliates of any documents, work papers or other materials or information related to the Assets.

(b)Seller and its Affiliates shall not disclose, directly or indirectly, any documents, work papers or other materials of a confidential or proprietary nature related to Buyer and its Affiliates (including, without limitation, any information obtained in connection with the entering into of this Agreement) and shall have all such information kept confidential; provided, however, that Seller may disclose any such information (A) that is or becomes generally available to the public other than as a result of disclosure by Seller or its Affiliates, (B) that is or becomes available to Seller on a non-confidential basis from a source that is not bound by a confidentiality obligation to Buyer, (C) to Seller’s financial advisors, consultants, attorneys and banks or (D) with the prior written approval of Buyer, which approval shall not be unreasonably withheld or delayed; provided, further, that to the extent that Seller or its Affiliates may become legally compelled to disclose any such information by any Governmental Authority or if Seller or its Affiliates receives an opinion of counsel that disclosure is required in order to avoid violating any applicable Law, Seller or its Affiliates may disclose such information but only after, if applicable or relevant, they have used all commercially reasonable efforts to afford Buyer, at its sole cost and expense, the opportunity to obtain an appropriate protective order, or other satisfactory assurance of confidential treatment, for the information required to be disclosed; provided, further, that Seller may disclose such information to the extent necessary to comply with applicable Law, or to enforce its rights and obligations under this Agreement.

ARTICLE VII
CONDITIONS TO CLOSING

Section 7.1.Conditions to Obligations of Seller and Buyer Under this Agreement.  The respective obligations of the Parties to consummate the transactions contemplated hereby shall be subject to the satisfaction at or prior to the Closing of the following conditions (any or all of which may be waived by the Parties, as the case may be in whole or in

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part, to the extent permitted by applicable Law):  (i) the termination or expiration of the applicable waiting period under the HSR Act and any extension thereof (“HSR Approval”), (ii) the absence of any temporary restraining order, preliminary or permanent injunction or other judgment or order issued by any court of competent jurisdiction or other statute, rule or legal restraint of a Governmental Authority the effect of which prevents the consummation of the transactions contemplated hereby and (iii) the absence of any proceeding by any Governmental Authority challenging or seeking to restrain or prohibit the consummation of the transactions contemplated by this Agreement.

Section 7.2.Additional Conditions to Seller’s Obligation.  The obligation of Seller to effect the transactions contemplated hereby shall be subject to the satisfaction at or prior to the Closing of the following conditions, any or all of which may be waived by Seller, in whole or in part, to the extent permitted by applicable Law:

(a)Each of the representations and warranties of Buyer set forth in this Agreement shall be true and correct (it being understood that, for purposes of determining the accuracy of such representations and warranties, all “Buyer Material Adverse Effect” qualifications and other materiality qualifications contained in such representations and warranties shall be disregarded) as of the date hereof and as of the Closing Date as though made on and as of the Closing Date (except that, in each case, representations and warranties that speak as of a specified date shall have been true and correct only on such date) except for failures that would not be reasonably likely to have, individually or in the aggregate, a Buyer Material Adverse Effect, and Seller shall have received a certificate of an executive officer of Buyer, dated the Closing Date, to such effect.

(b)Buyer shall have performed or complied in all material respects with all agreements and covenants required by this Agreement to be performed or complied with by it on or prior to the Closing Date (including the deliveries at Closing pursuant to Section 1.5), and Seller shall have received a certificate of an executive officer of Buyer, dated the Closing Date, to such effect.

Section 7.3.Additional Conditions to Buyer’s Obligation.  The obligation of Buyer to effect the transactions contemplated hereby shall be subject to the satisfaction at or prior to the Closing of the following conditions, any or all of which may be waived by Buyer, in whole or in part, to the extent permitted by applicable Law:

(a)Each of the representations and warranties of Seller set forth in this Agreement shall be true and correct (it being understood that, for purposes of determining the accuracy of such representations and warranties, all “Seller Material Adverse Effect” qualifications and other materiality qualifications contained in such representations and warranties shall be disregarded) as of the date hereof and as of the Closing Date as though made on

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and as of the Closing Date (except that, in each case, representations and warranties that speak as of a specified date shall have been true and correct only on such date) except for failures that would not be reasonably likely to have, individually or in the aggregate, a Seller Material Adverse Effect, and Buyer shall have received a certificate of an executive officer of Seller, dated the Closing Date, to such effect.  **

(b)Seller shall have performed or complied in all material respects with all agreements and covenants required by this Agreement to be performed or complied with by it on or prior to the Closing Date (including the deliveries at Closing pursuant to Section 1.4), and Buyer shall have received a certificate of an executive officer of Seller, dated the Closing Date, to such effect.

ARTICLE VIII
TERMINATION

Section 8.1.Termination.  This Agreement may be terminated at any time prior to the Closing:

(a)by mutual written consent of the Parties;

(b)by Seller upon written notice to Buyer, if any of the conditions in Section 7.1 or Section 7.2 shall not have been fulfilled by the time required or shall have become incapable of fulfillment on or prior to the Termination Date;

(c)by Buyer upon written notice to Seller, if any of the conditions in Section 7.1 or Section 7.3 shall not have been fulfilled by the time required or shall have become incapable of fulfillment on or prior to the Termination Date; or

(d)by Buyer or Seller upon written notice to the other Party, if the Closing contemplated hereby shall not have occurred on or before May 2, 2011 (the “Termination Date”).

provided, however, that no Party shall be entitled to terminate this Agreement under this Section 8.1 if the Closing has failed to occur because such Party breached any provision under this Agreement and such breach has been the cause of, or resulted in, the event or condition purportedly giving rise to a right to terminate this Agreement under this Section 8.1 prior to the Closing.

Section 8.2.Effect of Termination.  Except for the provisions of Section 2.16, Section 4.6, Section 6.2, Section 6.6, Section 6.14, ARTICLE VIII, Section 9.10, Section 9.11, Section 10.4, Section 10.5, Section 10.6, Section 10.7, Section 10.8, Section 10.9, Section 10.10, Section 10.12 and ARTICLE XI, this Agreement shall, upon termination hereof pursuant to

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Section 8.1, forthwith become of no further force or effect and (a) there shall be no liability on the part of Seller or Buyer or any of their respective officers or directors to any other party and (b) all rights and obligations of any Party shall cease; provided, however, that any such termination shall not relieve Seller or Buyer from liability for any willful failure to perform or observe in any material respect any of its agreements or covenants herein that are to be performed or observed at or prior to Closing.

ARTICLE IX
SURVIVAL AND INDEMNIFICATION

Section 9.1.Survival Periods.  All representations and warranties of the Parties contained in this Agreement shall survive the Closing until the date that is ** after the Closing Date (the “Survival Period”), except that (i) the “Survival Period” for the representations and warranties set forth in Section 2.1 (Organization, Etc.), Section 2.2 (Authority Relative to this Agreement and the Other Transaction Documents) and Section 2.16 (Brokers; Finders and Fees) (the “Seller Fundamental Representations”) shall **, (ii) the “Survival Period” for the representations and warranties in Section 2.11 (Taxes) (the “Seller Tax Representation”) shall **, and (iii) the “Survival Period” for the representations and warranties set forth in Section 4.1 (Organization, Etc.), Section 4.2 (Authority Relative to this Agreement and the Other Transaction Documents) and Section 4.6 (Brokers; Finders and Fees) (the “Buyer Fundamental Representations” shall **.  Except as set forth above, the Parties hereto intend to shorten the statute of limitations and agree that no claims or causes of action may be brought against Seller or Buyer based upon breaches of any of the representations or warranties contained in ARTICLE II or ARTICLE IV after the Survival Period.  This Section 9.1 shall not limit any covenant or agreement of the Parties which contemplates performance after the Closing, including the covenants and agreements set forth in ARTICLE V, ARTICLE VI and this ARTICLE IX.

Section 9.2.Seller’s Agreement to Indemnify.

(a)Subject to the terms and conditions set forth herein, from and after the Closing, Seller shall indemnify and hold harmless Buyer and its directors, officers, employees, Affiliates, controlling Persons, agents and representatives and their respective successors and assigns (collectively, the “Buyer Indemnitees”) from and against all liability, demands, claims, actions or causes of action, penalties, fines, assessments, deficiencies, settlements, judgments, losses, damages, costs and expenses (including reasonable fees and expenses for attorneys, accountants, engineers and investigators) (collectively, “Buyer Damages”) asserted against or incurred by any Buyer Indemnitee as a result of or arising out of any of the following:

(i)a breach of any representation or warranty of Seller contained in ARTICLE II other than a Seller Fundamental Representation or the Seller Tax Representation;

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(ii)a breach of any Seller Fundamental Representation or the Seller Tax Representation;

(iii)a breach of any covenant of Seller contained in this Agreement;

(iv)the Excluded Assets and the Retained Liabilities; or

(v)the Langley Plant Environmental Matters.

(b)Seller’s obligation to indemnify Buyer Indemnitees pursuant to Section 9.2(a) is subject to the following limitations:

(i)No indemnification shall be made by Seller pursuant to Section 9.2(a)(i): (A) with respect to any individual item (or group of related items) of Buyer Damage unless such Buyer Damage exceeds ** and (B) unless the aggregate amount of all Buyer Damages of the Buyer Indemnitees with respect to Section 9.2(a)(i) (together with any Buyer Damages described in Section 9.2(c)(iii)(B)) shall exceed ** (such amount, the “Indemnification Deductible”) (after which point Seller will be obligated only to indemnify Buyer from and against Buyer Damages under Section 9.2(a)(i) (together with any Buyer Damages described in Section 9.2(c)(iii)(C)) in excess of the Indemnification Deductible but less than or equal to ** (the “Indemnification Ceiling”)).  The maximum amount that Seller shall be required to pay in the aggregate pursuant to Section 9.2(a)(i) and Section 9.2(a)(v) in respect of all Buyer Damages by all Buyer Indemnitees is the Indemnification Ceiling less the Indemnification Deductible, after which point Seller will not have an obligation to indemnify Buyer from and against further such Buyer Damage.

(ii)Seller’s obligation to indemnify Buyer under Section 9.2(a)(ii) through Section 9.2(a)(iv) shall not be subject to any of the limitations set forth in Section 9.2(b)(i); provided that the maximum amount that Seller shall be required to pay in the aggregate pursuant to Section 9.2(a) in respect of all Buyer Damages to all Buyer Indemnitees shall be the Unadjusted Purchase Price.

(iii)The amount of any Buyer Damages shall be reduced by (A) any amount directly received by a Buyer Indemnitee with respect thereto under any insurance coverage or for any other party alleged to be responsible therefor (except such amount shall be adjusted by any increase in insurance premiums payable by Buyer as a result of such insurance claim), (B) the amount of any Tax benefit actually realized by Buyer

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Indemnitee in the form of an actual refund or credit of current Taxes payable in the year the Loss is claimed by Buyer with respect the applicable indemnification against Seller and (C) any indemnity, contribution or other similar payment actually received by Buyer or any Buyer Indemnitee from any third Person with respect to such Buyer Damages.  If a Buyer Indemnitee directly or indirectly receives an amount under insurance coverage or from such other party with respect to Buyer Damages at any time subsequent to any indemnification provided by Seller pursuant to this Section 9.2, then such Buyer Indemnitee shall promptly reimburse Seller for any payment made or expense incurred by Seller in connection with providing such indemnification up to such amount received by Buyer Indemnitee.  Each Buyer Indemnitee shall take all reasonable steps to mitigate damages in respect of any claim for which such Buyer Indemnitee is seeking indemnification and shall use commercially reasonable efforts to avoid any costs or expenses associated with such claim and, if such costs and expenses cannot be avoided, to minimize the amount thereof.

(iv)Seller shall be obligated to indemnify Buyer Indemnitees only for those claims giving rise to Buyer Damages as to which Buyer Indemnitees have given Seller written notice thereof, and with respect to any claim pursuant to Section 9.2(a)(i), such notice must be given prior to the end of the Survival Period with respect to such claim.  Any written notice delivered by a Buyer Indemnitee to Seller with respect to Buyer Damages shall set forth with as much specificity as is reasonably practicable the basis of the claim for Buyer Damages and, to the extent reasonably practicable, a reasonable estimate of the amount thereof.

(c)Seller’s obligation to indemnify the Buyer Indemnities pursuant to Section 9.2(a)(v) is subject to the following limitations:

(i)Seller’s obligation to indemnify the Buyer Indemnitees pursuant to Section 9.2(a)(v) shall survive the Closing until **

(ii)Seller shall be obligated to indemnify Buyer Indemnitees only for those claims giving rise to Buyer Damages under Section 9.2(a)(v) as to which Buyer Indemnitees have given Seller written notice thereof, prior to the end of the survival period described in Section 9.2(c)(i).  Any written notice delivered by a Buyer Indemnitee to Seller with respect to Buyer Damages under Section 9.2(a)(v) shall set forth with as much specificity as is reasonably practicable the basis of the claim for Buyer Damages, a reasonable estimate of the amount thereof, and shall include copies of any correspondence with any Governmental Agency regarding the asserted Buyer Damages.

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(iii)The amount that Seller shall be required to pay pursuant to Section 9.2(a)(v) shall be ** until the aggregate amount of such Buyer Damages (together with any Buyer Damages described in Section 9.2(a)(i)) equals the Indemnification Deductible, and ** until the aggregate amount of such Buyer Damages (together with any Buyer Damages described in Section 9.2(a)(i)) equals the Indemnification Ceiling, after which Seller shall have no responsibility for any additional Buyer Damages under Section 9.2(a)(i) or Section 9.2(a)(v).

(iv)Buyer claims for indemnification under Section 9.2(a)(v) shall be ** to the extent applicable ** and to the extent Buyer has legal capacity to do so, **

(v)Buyer shall take all reasonable actions to avoid and minimize any claim for indemnification under Section 9.2(a)(v), **

(vi)Notwithstanding any other provision in this Agreement, Section 9.2(a)(v) shall constitute Buyer’s sole and exclusive remedy for any Buyer Damages related to Langley Plant Environmental Matters.

(d)The limitations on indemnification set forth in Section 9.2(b) shall not apply to any claim or Buyer Damages for fraud or willful misconduct on the part of Seller.

(e)In determining the amount of any claim or Buyer Damages, all materiality and “Seller Material Adverse Effect” qualifiers contained in any representations and warranties or covenants shall be ignored.

THIS INDEMNIFICATION IS EXPRESSLY INTENDED TO APPLY NOTWITHSTANDING ANY NEGLIGENCE (WHETHER SOLE, CONCURRENT, ACTIVE OR PASSIVE) OR OTHER FAULT OR STRICT LIABILITY ON THE PART OF BUYER INDEMNITEES (BUT NOT TO THE EXTENT OF SUCH BUYER INDEMNITEE’S WILLFUL MISCONDUCT OR GROSS NEGLIGENCE).

Section 9.3.Buyer’s Agreement to Indemnify.

(a)Subject to the terms and conditions set forth herein, from and after the Closing, Buyer shall indemnify and hold harmless Seller and its directors, officers, employees, Affiliates, controlling Persons, agents and representatives and their respective successors and assigns (collectively, the “Seller Indemnitees”) from and against all liability, demands, claims, actions or causes of action, penalties, fines, assessments, deficiencies, settlements, judgments, losses, damages, costs and expenses (including reasonable fees and expenses for attorneys, accountants, engineers and investigators) (collectively, “Seller

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Damages”) asserted against or incurred by any of Seller Indemnitees as a result of or arising out of any of the following:

(i)a breach of any representation or warranty contained in ARTICLE IV other than any Buyer Fundamental Representation;

(ii)a breach of any Buyer Fundamental Representation;

(iii)a breach of any covenant of Buyer contained in this Agreement; and

(iv)the Assumed Liabilities.

(b)Buyer’s obligation to indemnify Seller Indemnitees pursuant to Section 9.3(a) is subject to the following limitations:

(i)No indemnification shall be made by Buyer pursuant to Section 9.3(a)(i): (A) with respect to any individual item (or group of related items) of Seller Damage unless such Seller Damage exceeds ** and (B) unless the aggregate amount of all Seller Damages of the Seller Indemnitees with respect to Section 9.3(a)(i) shall exceed the Indemnification Deductible (after which point Buyer will be obligated only to indemnify Seller from and against Seller Damage in excess of the Indemnification Deductible but less than or equal to the Indemnification Ceiling).  The maximum amount that Buyer shall be required to pay in the aggregate pursuant to Section 9.3(a)(i) in respect of all Seller Damages by all Seller Indemnitees is the Indemnification Ceiling less the Indemnification Deductible, after which point Buyer will not have an obligation to indemnify Seller from and against further such Seller Damage.

(ii)Buyer’s obligation to indemnify Seller under Section 9.3(a)(ii) through Section 9.3(a)(iv) shall not be subject to any of the limitations set forth in Section 9.3(b)(i); provided that the maximum amount that Buyer shall be required to pay in the aggregate pursuant to Section 9.3(a) in respect of all Seller Damages to all Seller Indemnitees is the Unadjusted Purchase Price.

(iii)The amount of any Seller Damages shall be reduced by (A) any amount directly received by a Seller Indemnitee with respect thereto under any insurance coverage or for any other party alleged to be responsible therefor (except such amount shall be adjusted by any increase in insurance premiums payable by Seller as a result of such insurance claim), (B) the amount of any Tax benefit actually realized by Seller Indemnitee in the form of an actual refund or credit of current

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Taxes payable in the year the Loss is claimed by Seller with respect the applicable indemnification against Buyer and (C) any indemnity, contribution or other similar payment actually received by Seller or any Seller Indemnitee from any third Person with respect to such Seller Damages.  If Seller Indemnitees directly or indirectly receive any amounts under insurance coverage or from such other party with respect to Seller Damages at any time subsequent to any indemnification provided by Buyer pursuant to this Section 9.3, then Seller Indemnitees shall promptly reimburse Buyer, as the case may be, for any payment made or expense incurred by Buyer in connection with providing such indemnification up to such amount received by Seller Indemnitees.  Each Seller Indemnitee shall take all reasonable steps to mitigate damages in respect of any claim for which such Seller Indemnitee is seeking indemnification and shall use commercially reasonable efforts to avoid any costs or expenses associated with such claim and, if such costs and expenses cannot be avoided, to minimize the amount thereof.

(iv)Buyer shall be obligated to indemnify Seller Indemnitees only for those claims giving rise to Seller Damages as to which Seller Indemnitees have given Buyer written notice thereof, and with respect to a claim pursuant to Section 9.3(a)(i), such notice must be given prior to the end of the Survival Period.  Any written notice delivered by Seller Indemnitees to Buyer with respect to Seller Damages shall set forth with as much specificity as is reasonably practicable the basis of the claim for Seller Damages and, to the extent reasonably practicable, a reasonable estimate of the amount thereof.

(c)The limitations on indemnification set forth in Section 9.3(b) shall not apply to any claim or Seller Damages for fraud or willful misconduct on the part of Buyer.

(d)In determining the amount of any claim or Seller Damages, all materiality and “Buyer Material Adverse Effect” qualifiers contained in any representations and warranties or covenants shall be ignored.

THIS INDEMNIFICATION IS EXPRESSLY INTENDED TO APPLY NOTWITHSTANDING ANY NEGLIGENCE (WHETHER SOLE, CONCURRENT, ACTIVE OR PASSIVE) OR OTHER FAULT OR STRICT LIABILITY ON THE PART OF SELLER INDEMNITEES (BUT NOT TO THE EXTENT OF SUCH SELLER INDEMNITEE’S WILLFUL MISCONDUCT OR GROSS NEGLIGENCE).

Section 9.4.Third Party Indemnification.     The obligations of Seller to indemnify Buyer Indemnitees under Section 9.2 with respect to Buyer Damages and the

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obligations of Buyer to indemnify Seller Indemnitees under Section 9.3 with respect to Seller Damages, in either case resulting from the assertion of liability by third parties (each, as the case may be, a “Claim”), will be subject to the following additional terms and conditions.  This Section 9.4 shall not apply to any claims or proceedings with respect to Taxes, which shall be governed by Section 5.4.

(a)Any Party against whom any Claim is asserted (the “Indemnified Party”) will give the indemnifying party (the “Indemnifying Party”) written notice of any such Claim promptly after learning of such Claim, and the Indemnifying Party may at its option and its sole expense undertake the defense thereof using reputable counsel and representatives of its own choosing who are reasonably satisfactory to the Indemnified Party; provided that the Indemnified Party shall be entitled to conduct and control the defense thereof (at their election and sole expense) if such Claim, based on the remedy sought, would reasonably be expected to subject any party to criminal liability of, or injunctive or other equitable relief against, the Indemnified Party (except as set forth in Section 6.10).  All Claims are subject to the remaining obligations set forth in this Section 9.4(a) and Section 9.4(b).  The Indemnified Party may participate, through counsel chosen by it and at its own expense, in the defense of any Claim as to which the Indemnifying Party has elected to conduct and control the defense, compromise or settlement thereof; provided that if counsel to the Indemnifying Party is ethically prohibited from representing the Indemnified Party due to the existence or development of a conflict between the interests of the Indemnifying Party and the Indemnified Party, then the Indemnifying Party shall also pay the reasonable fees and expenses of one separate counsel (reasonably acceptable to the Indemnifying Party) of the Indemnified Party in connection with such Claim during such time as such a conflict exists.  In the event, however, that the Indemnifying Party declines or does not elect to conduct and control the defense, compromise or settlement of any Claim or to employ reputable counsel reasonably satisfactory to the Indemnified Party, in either case within such 30 day period, then the Indemnifying Party shall pay the reasonable fees and expenses of counsel for the Indemnified Party as incurred to the extent the Indemnifying Party is obligated to indemnify the Indemnified Party for such fees and expenses pursuant to this Section 9.4(a), as applicable; provided, however, that the Indemnifying Party shall not be required to pay the fees and disbursements of more than one firm for all Indemnified Parties in any Claim.  The Indemnifying Party or the Indemnified Party (as the case may be) shall at all times use commercially reasonable efforts to keep the Indemnifying Party or Indemnified Party (as the case may be) reasonably apprised of the status of the defense of any matter the defense of which it is maintaining and to cooperate in good faith with each other with respect to the defense of any such matter and shall furnish such records and other information as may be reasonably requested by the Indemnifying Party or Indemnified Party (as the case may be) in connection therewith.  Failure to give prompt notice of a

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Claim hereunder shall not affect the Indemnifying Party’s obligations under this ARTICLE IX, except to the extent the Indemnifying Party is materially prejudiced by such failure to give prompt notice.

(b)Neither the Indemnifying Party nor the Indemnified Party, as the case may be, shall pay, compromise, settle or consent to the entry of any judgment with respect to which indemnification is being sought herein without the prior written consent of the other Party, which consent may not be unreasonably withheld, delayed or conditioned; provided, however, that the Indemnified Party’s/Indemnifying Party’s (as applicable) consent will not be required if such settlement, compromise or consent includes an unconditional release of the Indemnified Party/Indemnified Party (as applicable) from all liability arising out of such claim and such settlement, compromise or consent does not contain any equitable order, judgment or term that may adversely affect the business of the Indemnified Party/Indemnifying Party (as applicable) (other than as the result of money damages covered by the indemnity).  If the Indemnifying Party is entitled to conduct and control the defense of any particular claim pursuant to this Section 9.4, but elects not to do so, then the Indemnifying Party shall not unreasonably withhold its consent to any settlement or compromise with respect to such claim.

Section 9.5.Insurance.  The Indemnifying Party shall be subrogated to the rights of the Indemnified Party in respect of any insurance relating to Buyer Damages or Seller Damages, as the case may be, to the extent of any indemnification payments made hereunder, and the Indemnified Party shall provide all reasonably requested assistance to the Indemnifying Party in respect of such subrogation.

Section 9.6.No Duplication.  Any liability for indemnification hereunder shall be determined without duplication of recovery by reason of the state of facts giving rise to such liability constituting a breach of more than one representation, warranty, covenant or agreement herein.

Section 9.7.Amount of Losses.  The determination of the dollar amount of any Buyer Damages or Seller Damages, as the case may be, shall be based solely on the actual dollar value thereof, on a dollar-for-dollar basis, and shall not take into account any multiplier valuations, including any multiple based on earnings or other financial indicia.

Section 9.8.Remedies Exclusive.  Indemnification under this ARTICLE IX will be the exclusive remedy of any Indemnified Party for any breach of a representation or warranty in this Agreement and, in furtherance of the foregoing, each of the Parties, on behalf of itself and its Affiliates, hereby waives and releases the other Parties hereto (and such other Parties’ Affiliates) from, to the fullest extent permitted under any applicable Law, any and all rights, claims and causes of action it or its Affiliates may have against the other Parties hereto except as provided herein and provided, further, that nothing in this ARTICLE IX shall limit in any way

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either Party’s remedies in respect of fraud or willful misconduct by the other Party in connection with the transactions contemplated hereby.

Section 9.9.Casualty and Condemnation.  If, after the date of this Agreement but prior to the Closing Date, any portion of the Assets is destroyed or damaged by fire or other casualty or is expropriated or taken in condemnation or under right of eminent domain, Buyer shall, nevertheless be required to comply with the covenants in ARTICLE I and attend the Closing.  In the event that the amount of the costs and expenses associated with repairing or restoring all Assets affected by such casualty or condemnation exceeds **, Seller must elect by written notice to Buyer prior to Closing either (i) to cause the Assets affected by any casualty or condemnation to be repaired, restored or replaced, at Sellers’ sole cost, as promptly as reasonably practicable (which work may extend after the Closing Date) or (ii) to indemnify Buyer through a document reasonably acceptable to the Parties against any costs or expenses that Buyer reasonably incurs to repair, restore or replace the Assets subject to any casualty.  In the case of (i) and (ii) above, Seller shall retain all rights to insurance and other claims against third Persons with respect to the casualty or taking except to the extent the Parties otherwise agree in writing.  Notwithstanding the foregoing, in the event that either (x) the above mentioned costs and expenses exceed ** or (y) the loss or taking of the affected Assets would substantially prevent the operation of the Processing Facilities or the operation or construction of the Ranger NGL Pipeline in the ordinary course of business consistent with past practices, then either Party will have the right to terminate this Agreement prior to Closing if Seller elects not to proceed under (i) or (ii) above.

Section 9.10.No Special Damages.  IN NO EVENT SHALL ANY PARTY BE LIABLE UNDER THIS ARTICLE IX OR OTHERWISE IN RESPECT OF THIS AGREEMENT FOR EXEMPLARY, SPECIAL, PUNITIVE, INDIRECT, REMOTE, SPECULATIVE OR CONSEQUENTIAL DAMAGE; PROVIDED, HOWEVER, IF ANY OF THE SELLER INDEMNITEES OR BUYER INDEMNITEES IS HELD LIABLE TO A THIRD PERSON FOR ANY SUCH DAMAGES AND THE INDEMNITOR IS OBLIGATED TO INDEMNIFY SUCH SELLER INDEMNITEE OR BUYER INDEMNITEE FOR THE MATTER THAT GAVE RISE TO SUCH DAMAGES, THE INDEMNITOR SHALL BE LIABLE, AND OBLIGATED TO REIMBURSE SUCH INDEMNITEES, FOR SUCH DAMAGES.

Section 9.11.Conspicuous Legends; Nature of Indemnification.  THE PARTIES AGREE THAT THE BOLD OR CAPITALIZED LETTERS IN THIS AGREEMENT CONSTITUTE CONSPICUOUS LEGENDS.  IT IS EXPRESSLY ACKNOWLEDGED THAT THE INDEMNIFICATION PROVIDED IN THIS ARTICLE IX COULD INVOLVE INDEMNIFICATION FOR NEGLIGENCE OR UNDER THEORIES OF STRICT LIABILITY.

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ARTICLE X
MISCELLANEOUS PROVISIONS

Section 10.1.Amendment and Modification.  This Agreement may be amended, modified or supplemented at any time by the Parties hereto, pursuant to an instrument in writing signed by all of the Parties.

Section 10.2.Entire Agreement; Assignment.  This Agreement (including the exhibits and schedules hereto) (a) constitutes the entire agreement among the Parties hereto with respect to the subject matter hereof and supersede other prior agreements and understandings, both written and oral, between the Parties hereto with respect to the subject matter hereof and (b) shall not be assigned, by operation of law or otherwise, by a Party hereto, without the prior written consent of the other Parties.

Section 10.3.Severability.  The invalidity or unenforceability of any term or provision of this Agreement in any situation or jurisdiction shall not affect the validity or enforceability of the other terms or provisions hereof or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction and the remaining terms and provisions shall remain in full force and effect, unless doing so would result in an interpretation of this Agreement which is manifestly unjust.

Section 10.4.Notices.  All notices, requests, claims, demands and other communications required or permitted to be given hereunder will be in writing and will be given when delivered by hand or sent by registered or certified mail (postage prepaid, return receipt requested) or by overnight courier (providing proof of delivery) or by facsimile (providing confirmation of transmission).  All such notices, requests, claims, demands or other communications will be addressed as follows:

(a)if to Seller:

EQT Gathering, LLC
EQT Plaza
625 Liberty Avenue, Suite 1700
Pittsburgh, Pennsylvania  15222
Facsimile:  (412) 395-2114
Attention:  President

with a copy (which shall not constitute notice) to

EQT Gathering, LLC
EQT Plaza
625 Liberty Avenue, Suite 1700
Pittsburgh, Pennsylvania  15222
Telephone:  (412) 553-5700

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Facsimile:  (412) 553-7781
Attention:  General Counsel

with a copy (which shall not constitute notice) to

Baker Botts L.L.P.
One Shell Plaza
910 Louisiana Street
Houston, TX  77002
Facsimile:  (713) 229-7778
Attention:  Hugh Tucker

(b)if to Buyer:

MarkWest Energy Appalachia, L.L.C.
1515 Arapahoe Street

Tower 1, Suite 1600

Denver, CO 80202

Attention: Senior Vice President and Chief Commercial Officer

Facsimile: (303) 925-9305

with a copy to

MarkWest Energy Appalachia, L.L.C.
1515 Arapahoe Street

Tower 1, Suite 1600

Denver, CO 80202

Attention: General Counsel

Facsimile: (303) 925-9308

with a copy (which shall not constitute notice) to

Hogan Lovells US LLP
One Tabor Center

1200 Seventeenth St., Ste. 1500
Denver, CO 80202
Facsimile:  (303) 899-7333
Attention:  George Hagerty

or in any case to such other address or addresses as hereafter shall be furnished as provided in this Section 10.4 by any Party to the other Parties.

Section 10.5.Governing Law, Exclusive Jurisdiction and Waiver of Jury Trial.

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(a)THIS AGREEMENT AND THE LEGAL RELATIONS BETWEEN THE PARTIES HERETO SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF PENNSYLVANIA, USA WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

(b)THE PARTIES HERETO HEREBY IRREVOCABLY SUBMIT TO THE EXCLUSIVE JURISDICTION OF THE STATE COURTS OF PENNSYLVANIA LOCATED IN ALLEGHENY COUNTY, PENNSYLVANIA OR THE FEDERAL COURTS OF THE UNITED STATES OF AMERICA LOCATED IN ALLEGHENY COUNTY, PENNSYLVANIA AND APPROPRIATE APPELLATE COURTS THEREFROM, AND EACH PARTY HEREBY IRREVOCABLY AGREES THAT ALL CLAIMS IN RESPECT OF SUCH DISPUTE, CONTROVERSY OR CLAIM MAY BE HEARD AND DETERMINED IN SUCH COURTS.  THE PARTIES HEREBY IRREVOCABLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAWS, ANY OBJECTION WHICH THEY MAY NOW OR HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY SUCH DISPUTE, CONTROVERSY OR CLAIM BROUGHT IN ANY SUCH COURT OR ANY DEFENSE OF INCONVENIENT FORUM FOR THE MAINTENANCE OF SUCH DISPUTE, CONTROVERSY OR CLAIM.

(c)EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES ALL RIGHT TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR RELATING TO THIS AGREEMENT.

Section 10.6.Descriptive Headings.  The descriptive headings herein are inserted for convenience of reference only and shall in no way be construed to define, limit, describe, explain, modify, amplify, or add to the interpretation, construction or meaning of any provision of, or scope or intent of, this Agreement nor in any way affect this Agreement.

Section 10.7.Counterparts.  This Agreement may be executed in multiple counterparts, all of which shall be deemed an original, but both of which together shall constitute one and the same instrument.

Section 10.8.Fees and Expenses.  Except as otherwise provided herein, all costs and expenses (including legal and financial advisory fees and expenses) incurred in connection with, or in anticipation of, this Agreement and the transactions contemplated hereby shall be paid by the Party hereto incurring such expenses.  Seller, on the one hand, and Buyer, on the other hand, shall indemnify and hold harmless the other Party or Parties, as applicable, from and against any and all claims or liabilities for financial advisory and finders’ fees incurred by reason of any action taken by such Party or Parties or otherwise arising out of the transactions

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contemplated by this Agreement by any Person claiming to have been engaged by such Party or Parties.

Section 10.9.Interpretation.

(a)The phrase “to the Knowledge of Seller” or any similar phrase shall mean those facts, events or circumstances actually known after reasonable inquiry to the individuals identified in Section 10.9 of the Disclosure Schedule; the phrase “to the Knowledge of Buyer” or any similar phrase shall mean those facts, events or circumstances actually known after reasonable inquiry to any executive officer of Buyer.

(b)Any reference to any federal, state, local, or foreign Law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise.

(c)For purposes of this Agreement, the terms “hereof,” “herein” and “herewith” and words of similar import will, unless otherwise stated, be construed to refer to this Agreement as a whole and not to any particular provision of this Agreement, (ii) the word “including” and words of similar import when used in this Agreement will mean “including, without limitation,” unless otherwise specified, (iii) the word “or” will not be exclusive unless expressly provided to the contrary, and (iv) words in the singular will be held to include the plural.

(d)All references to Articles and Sections refer to articles and sections of this Agreement, all references to Exhibits refer to exhibits to this Agreement and all references to Schedules refer to Schedules to this Agreement, which Exhibits and Schedules are attached hereto and made a part hereof for all purposes.

(e)In the event an ambiguity or question of intent or interpretation arises, this Agreement shall be construed as if drafted jointly by the Parties and no presumption or burden of proof shall arise favoring or disfavoring any Party by virtue of the authorship of any provisions of this Agreement.

Section 10.10.No Third Party Beneficiaries.  This Agreement is solely for the benefit of (a) Seller (and its successors and permitted assigns) and Seller Indemnitees, with respect to the obligations of Buyer under this Agreement; and (b) Buyer (and its successors and permitted assigns) and Buyer Indemnitees, with respect to the obligations of Seller under this Agreement.  This Agreement shall not be deemed to confer upon or give to any other third party any remedy, claim of liability or reimbursement, cause of action or other right.

Section 10.11.No Waivers.  Except as otherwise expressly provided herein, no failure to exercise, delay in exercising, or single or partial exercise of any right, power or remedy by any Party, and no course of dealing between the Parties, shall constitute a waiver of any such

48

right, power or remedy.  No waiver by a Party of any default, misrepresentation, or breach of warranty or covenant hereunder, whether intentional or not, shall be deemed to extend to any prior or subsequent default, misrepresentation, or breach of warranty or covenant hereunder or affect in any way any rights arising by virtue of any prior or subsequent such occurrence.  No waiver shall be valid unless in writing and signed by the Party against whom such waiver is sought to be enforced.

Section 10.12.Specific Performance.  The Parties hereto agree that if any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached, irreparable damage would occur, no adequate remedy at law would exist and damages would be difficult to determine, and that the Parties shall be entitled to specific performance of the terms hereof and immediate injunctive relief, without the necessity of proving the inadequacy of money damages as a remedy, in addition to any other remedy at law or in equity.

Section 10.13.Facsimile Signature.  This Agreement and the documents contemplated hereby may be executed by facsimile, portable document format (.pdf) or similar technology signature.

ARTICLE XI
DEFINITIONS

Section 11.1.Certain Definitions.  When used in this Agreement, the following terms shall have the respective meanings specified therefor below.

(a)“Affiliate” means , with respect to any Person, a Person that directly or indirectly controls, is controlled by or is under common control with such Person, with control in such context (including, with its correlative meaning, “controlled by” and “under common control with”) meaning the possession, directly or indirectly, of the power to direct or cause the direction of management or policies of a Person, whether through the ownership of securities or partnership or other ownership interests, by contract or otherwise.

(b)“Antitrust Law” means any applicable federal, state, local or foreign statute, Law, rule or regulation designed to prohibit mergers, acquisitions and joint ventures which tend to lessen competition or which are designed to prohibit, restrict or regulate conduct which has the purpose or effect of restraining trade, monopolizing or abusing a dominant position, including the HSR Act.

(c)“Applicable Index Price”  with respect to volumes of propane, isobutane and normal butane, means the arithmetic average for the five calendar day period immediately prior to the Closing Date of the daily high and low Mont Belvieu TET price for each of propane, isobutane and normal butane,

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respectively; and, with respect to volumes of natural gasoline, the arithmetic average for the five calendar day period immediately prior to the Closing Date of the daily high and low Mont Belvieu non-TET price for natural gasoline, in each case as reported by Oil Price Information Service.

(d)“Assets” means the following assets and properties, except for the Excluded Assets:

(i)Langley Plant 1, Langley Plant 2 (collectively, the “Langley Plants ) and all assets and properties related thereto described in Part I of Exhibit A-1, and all meter stations, gas processing plants, treaters, dehydration units, compressor stations, processing skids, fractionators, NGL handling facilities, platforms, warehouses, field offices, control buildings, pipelines, pipe valves, NGL measurement facilities, tanks and other associated facilities that are necessary to or are primarily used or held for use in connection with the ownership, operation, use or maintenance of the Langley Plants, as more particularly defined in Part I of Exhibit A-1 (collectively, the “Processing Facilities”);

(ii)the Ranger NGL Pipeline, the Dormant Pipeline and all assets and properties related thereto, including those described in Part II of Exhibit A-1;

(iii)the physical inventory at the Effective Time of NGL volumes in (A) the Ranger NGL Pipeline, (B) stock tanks a the Ranger Truck Terminal, and (C) loaded in trucks for transport to the Ranger Truck Terminal or the Siloam Fractionation Plant (collectively, the “Inventory”);

(iv)all tangible personal property of every kind and nature that is primarily used in the ownership, operation, use or maintenance of the Processing Facilities, the Ranger NGL Pipeline and the Ranger Truck Terminal, including motor vehicles, pipelines, meters, gauges, valves, engines, field equipment, office equipment, fixtures (except to the extent included within Real Property Interests), trailers, tools, instruments, spare parts, machinery, computer equipment, telecommunications equipment, furniture, supplies, materials and other improvements (except to the extent included within Real Property Interests) wherever located, including those items of tangible personal property described in Exhibit A-2 (collectively, the “Personal Property”);

(v)all fee property, rights-of-way, easements, surface use agreements, licenses, leases, leasehold estates, and other rights, privileges or interests in real property that are primarily used in the ownership, operation, use or maintenance of the Processing Facilities, the Ranger NGL Pipeline and the Ranger Truck Terminal and the Martin’s Branch expansion of the Processing

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Facilities (collectively, the “Real Property Interests”), all as described in Exhibit A-3, and all fixtures, buildings and improvements located on or under such Real Property Interests;

(vi)all benefits and rights under permits, licenses, certificates, orders, approvals, authorizations, grants, Consents, concessions, waivers, registrations, warrants, franchises and similar rights and privileges that are granted by a Governmental Authority or other Person and are necessary for, or are used or held for use primarily for or in connection with, the ownership, operation, use or maintenance of the Processing Facilities, the Ranger NGL Pipeline, the Personal Property or the Real Property Interests, including those described in Exhibit A-4 (collectively, the “Permits”);

(vii)all benefits and rights under the Contracts identified on Exhibit A-5 (collectively, the “Assigned Contracts”); provided that no Assigned Contract with the notation “W Prior Consent” will be assigned to Buyer under this Agreement unless and until the required Consent to assignment has been received;

(viii)all benefits and rights under the radio licenses identified on Exhibit A-6 (the “Radio Licenses”); provided that no Radio License will be assigned to Buyer under this Agreement unless and until any required Consent to assignment has been received;

(ix)all technical information, shop rights, designs, plans, manuals, specifications and other proprietary and nonproprietary technology and data primarily used in connection with the ownership, operation, use or maintenance of the Processing Facilities, the Ranger NGL Pipeline or the Personal Property;

(x)all rights and benefits of the following insofar as the same relate primarily to any of the Assets for any period from and after the Effective Time: (A) all purchase orders, invoices, storage or warehouse receipts, bills of lading, certificates of title and documents, and (B) all keys, lock combinations, computer access codes and other devices or information necessary to gain entry to or take possession of such Assets;

(xi)copies or originals of all tangible, digital or electronic contracts, land, title, engineering, environmental, operating, performance, safety, maintenance, warranty, accounting, business, marketing, and other data, files, documents, instruments, notes, correspondence, papers, ledgers, journals, reports, abstracts, surveys, maps, books, records, designs, plans, blueprints, as-built plans and specifications and system drawings and studies which relate primarily to the Assets or which are used or held for use primarily in

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connection with, the ownership, operation, use or maintenance of the Assets; provided, however, such material shall not include (A) any proprietary data that is not primarily used in connection with the continued ownership, use or operations of the Assets, (B) any information subject to third Person confidentiality agreements for which a Consent or waiver cannot be secured after commercially reasonable efforts with no obligation to spend money, (C) any information which, if disclosed, would violate an attorney-client privilege or would constitute a waiver of rights as to attorney work product or attorney-client privileged communications, unless such information is needed for operation of the Processing Facilities or the Ranger NGL Pipeline, and the Parties enter a mutually agreeable joint defense agreement related thereto or (D) any information relating primarily to the Excluded Assets (collectively, the “Records”); and

(xii)the benefits in and rights to enforce all claims, causes of action, indemnities, rights of recovery, rights of set off, rights of recoupment, warranties, covenants, guarantees, and all suretyship agreements (and all proceeds from any of the foregoing) to the extent relating primarily to the Assets or the Assumed Liabilities with respect to periods from and after the Effective Time.

(e)“Assumed Liabilities” means, subject to Buyer’s indemnification rights hereunder and except as otherwise set forth in this Agreement, any and all obligations and liabilities, known or unknown, with respect to (i) the Assets or the ownership, operation or use thereof, (ii) any Hired Employee or (iii) all liabilities under the Ivel NOPV that are not Retained Liabilities; regardless of whether such obligations or liabilities arose prior to, on or after the Effective Time, including the Langley Plant Environmental Matters.

(f)“Authorizations” means any franchise, permit, license, authorization, order, certificate, registration, variance, settlement, compliance plan or other Consent or approval granted by any Governmental Authority (i) under any Law, including any Environmental Law or Antitrust Law, or (ii) under or pursuant to any judgment or material Contract with any such Governmental Authority.

(g)“Benefit Plan” means any: (i) employee benefit plan as defined in Section 3(3) of ERISA and (ii) other employee benefit agreement or arrangement, including a deferred compensation plan, incentive plan, bonus plan or arrangement, stock option plan, stock purchase plan, stock award plan, golden parachute agreement, severance plan, dependent care plan, cafeteria plan, employee assistance program, scholarship program, employment contract, retention incentive agreement, non-competition agreement, consulting agreement, vacation policy, and other similar plan, agreement and arrangement.

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(h)“Big Sandy Pipeline” means the existing pipeline that is owned and operated by Equitrans, L.P. that transports Gas from the Processing Facilities to the Tennessee Gas Pipeline Company’s Broad Run Lateral.

(i)“Big Sandy Shared Services Agreement” means that certain Big Sandy Shared Services Agreement, dated as of the Closing Date, by and between the Parties, substantially in the form agreed to by the Parties on or prior to the date hereof, whereby the Parties address, among other things, certain arrangements with respect to (i) the provision by Buyer of certain services relating to the operation of the Compression Equipment (as defined therein) for the Big Sandy Pipeline, (ii) the procedures relating to the separation of control systems at the Processing Facilities that are shared with the Compression Equipment, (iii) access to, and allocation of expenses for, power for the Compression Equipment, and (iv) qualification for sales tax exemption regarding power consumption at the Processing Facilities.

(j)“Business Day” means any day other than a Saturday, a Sunday, or a day on which banks are closed for business in New York, New York or Denver, Colorado.

(k)“Buyer Subsidiary” means any one or more wholly owned subsidiary of Buyer designated by Buyer as a “Buyer Subsidiary” hereunder prior to the Closing Date.

(l)“Code” means the U.S. Internal Revenue Code of 1986, as amended.

(m)“Consent” means any approval, authorization, consent, order, license, declaration, permission, permit, qualification, exemption or waiver by any third party or Governmental Authority.

(n)“Contract” means any contract, agreement, lease, ground lease, or commitment, license, sublicense, permit, mortgage, purchase order, indenture, loan agreement, note, lease, sublease, agreement, obligation, commitment, understanding, instrument or other arrangement (whether written or oral) or any commitment to enter into any of the foregoing.

(o)“Controlled Group Liability” means any and all Liabilities (a) under Title IV of ERISA, (b) under Section 302 of ERISA, (c) under Sections 412 and 4971 of the Code, (d) as a result of the failure to comply with the continuation of coverage requirements of Section 601 et seq. of ERISA and Section 4980B of the Code and (e) under corresponding or similar provisions of any foreign Laws.

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(p)“Defensible Title” means title that is free and clear of all Liens other than Permitted Encumbrances and good and otherwise free from reasonable doubt such that a prudent person engaged in the business of the ownership and operation of assets similar to the Assets where located, with knowledge of all the facts and their legal effect, would be willing to accept the same.

(q)“Demand” means any demand, demand letter, claim or notice by any Person of noncompliance, violation, or liability, or of a Proceeding, other than any claim for workers’ compensation or unemployment compensation benefits or claims under a Benefit Plan.

(r)“Dormant Pipeline” means the dormant NGL pipeline that runs from the site of the Processing Facilities to its terminus near Institute, West Virginia.

(s)“Effective Time” means 12:00 A.M. Eastern time on the Closing Date.

(t)“Environment” means soil, sediment, surface water, groundwater, land, subsurface strata and indoor or ambient air.

(u)“Environmental Law” means the Comprehensive Environmental Response, Compensation and Liability Act, 42 U.S.C. § 9601 et seq.; the Resource Conservation and Recovery Act, 42 U.S.C. § 6901 et seq.; the Federal Water Pollution Control Act, 33 U.S.C. § 1251 et seq.; the Clean Air Act, 42 U.S.C. § 7401 et seq.; the Hazardous Materials Transportation Act, 49 U.S.C. § 5101 et seq.; the Toxic Substances Control Act, 15 U.S.C. §§ 2601 through 2629; the Oil Pollution Act, 33 U.S.C. § 2701 et seq.; the Emergency Planning and Community Right to Know Act, 42 U.S.C. § 11001 et seq.; and the Safe Drinking Water Act, 42 U.S.C. §§ 300f through 300j, in each case as amended on or prior  to the Closing Date, and all similar Laws as in effect on or prior to the Closing Date of any Governmental Authority having jurisdiction over the Assets addressing pollution or protection of the environment or natural resources and all regulations implementing the foregoing, and regional, state or local Laws pertaining to oil and natural gas exploration, production, gathering, and processing wastes, the use, maintenance, and closure of pits and impoundments, or the acquisition, withdrawal, consumptive use, reclamation and disposal of water, produced water, and flowback water in connection with, oil and natural gas upstream and midstream activities.

(v)“Environmental Liability” means any Liability (i) resulting from or attributable to the actual or threatened Releases of Hazardous Materials into the Environment or resulting from or attributable to exposure to Hazardous

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Materials; (ii) arising under Environmental Laws or under any Contract and resulting from or attributable to the generation, manufacture, processing, distribution, use, treatment, storage, Release or threatened Release, transport, or handling of Hazardous Materials; or (iii) otherwise arising under or related to Environmental Laws or the violation thereof.

(w)“Environmental Permit” means any permit, registration, license, certificate, approval, exemption, variance or other authorization required by a Governmental Authority under any Environmental Laws.

(x)“EQT Subsidiary” means Seller or any wholly-owned subsidiary of EQT Corporation, a Pennsylvania corporation.

(y)“ERISA” means the Employee Retirement Income Security Act of 1974, as amended.

(z)“Excluded Assets” means:

(i)all claims for refunds of, and any loss or credit carry forwards with respect to, any Taxes related to any Pre-Closing Period;

(ii)all work product of Seller’s or its Affiliates’ attorneys relating to the negotiation and consummation of the transactions contemplated hereby;

(iii)all contracts, property and assets listed on Exhibit B (including the compression and related equipment for the Big Sandy Pipeline and all control systems related thereto) that are not assigned to Buyer and any other contracts, properties and assets: (a) upstream of the Processing Facilities; or (b) downstream of the Processing Facilities and the Ranger NGL Pipeline;

(iii)all proceeds, claims and rights arising prior to the Effective Time under any insurance policies covering the Assets;

(iv)any hedging agreement, including any derivative, swap, option, future, put, call, floor, cap, collar, master agreement or other contract intended to hedge a commodity or interest rate, associated with or encumbering the Assets;

(v)any and all rights, causes of action and defenses against third Persons relating to any of the Excluded Assets and arising at any time;

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(vi)any Gas or NGLs that (A) are located in stock tanks at the Processing Facilities or (B) constitute linefill at the Processing Facilities; and

(vii)any Benefit Plan of Seller or its Affiliates.

(aa)“Gas” means all hydrocarbon and non-hydrocarbon substances produced from gas or oil wells in a gaseous state.

(bb)“Governmental Authority” means (i) national, state, county, municipal, or local government (whether domestic or foreign) and any political subdivision thereof, (ii) any court or administrative tribunal, (iii) any other governmental, quasi-governmental, judicial, public or statutory instrumentality, authority, body, agency, bureau or entity of competent jurisdiction (including any zoning authority, or state public utility commission, or any comparable authority), (iv) any non-governmental agency, tribunal or entity that is properly vested by a governmental authority with applicable jurisdiction, or (v) any arbitrator.

(cc)“Hazardous Materials” means any substance, material, waste or radiation  including any: (a) chemical, product, material, substance or waste defined as or included in the definition of “hazardous substance,” “hazardous material,” “hazardous waste,” “restricted hazardous waste,” “extremely hazardous waste,” “solid waste,” “toxic waste,” “extremely hazardous substance,” “chemical substance,” “toxic pollutant,” “contaminant” or “pollutant”; (b) hydrocarbons, petroleum, petrochemical or petroleum products, petroleum substances, NGL, condensate, natural gas, crude oil or any components, fractionations or derivatives thereof; (c) oil and gas exploration and production wastes, including produced and flow back waters; and (d) asbestos containing materials, mercury, polychlorinated biphenyls, mold, radioactive materials, urea formaldehyde foam insulation, or radon gas.

(dd)“HSR Act” means the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended.

(ee)“Langley Plant 1” means the Gas processing facility described in Part I of Exhibit A-1.

(ff)“Langley Plant 2” means the refrigerated JT Gas processing facility described in Part I of Exhibit A-1.

(gg)“Langley Plant Environmental Matters” means any Remediation or Liability for **

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(hh)“Laws” all laws, statutes, rules, regulations, ordinances, orders, writs, injunctions, decrees, requirements, judgments and codes of Governmental Authorities, including obligations arising under the common law.

(ii)“Lease and Easement Properties” means all Real Property Interests except for Owned Real Property.

(jj)“Liabilities” means liabilities, obligations and commitments (including guarantees and other forms of credit support), whether accrued, contingent, absolute, determined, determinable or otherwise, including all debts, losses, deficiencies, costs, expenses, fines, interest, expenditures, claims, suits, proceedings, judgments, demands, damages, and reasonable attorneys’, accountants’ and other similar fees and expenses and reasonable expenses of investigating, defending and prosecuting litigation, including those arising under any Law or Proceeding and those arising under any Contract or otherwise.

(kk)“Lien” means any mortgage, pledge, hypothecation, security interest, lien, charge, option, assignment or encumbrance of any kind or any arrangement to provide priority or preference, including any easement, right-of-way, restriction (whether on voting, sale, transfer, disposition, use or otherwise), right, lease and other encumbrance on title to real or personal property (whether or not of record), whether voluntary or imposed by Law, and any agreement to give any of the foregoing; provided, however, that “Lien” shall not include any Real Property Consent.

(ll)“Loss” or “Losses” means any and all damages, demands, payments, obligations, penalties, costs of supplemental environmental projects, assessments, disbursements, claims, costs, Liabilities, losses, causes of action, and expenses, including interest, awards, judgments, settlements, fines, fees, costs of defense and attorneys’ fees, costs of accountants, expert witnesses and other professional advisors and costs of investigation and preparation of any kind or nature whatsoever.

(mm)“MarkWest Agreements” means the following agreements:

(i)Natural Gas Liquids Transportation, Fractionation and Marketing Agreement dated November 16, 2007 by and between Seller and MarkWest Energy Appalachia, L.L.C.;

(ii)Natural Gas Liquids Exchange Agreement dated November 16, 2007 by and between Seller and MarkWest Energy Appalachia, L.L.C.;

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(iii)Transfer of Operations, Assignment and Reimbursement Agreement dated November 16, 2007 by and among EQT Production Company, Seller and MarkWest Energy Appalachia, L.L.C.;

(iv)Netting, Financial Responsibility and Security Agreement dated September 23, 2004 by and between EQT Production Company and MarkWest Hydrocarbon, Inc., as amended by the parties thereto on November 16, 2007;

(v)Netting Financial Responsibility and Security Agreement dated September 23, 2004 by and between EQT Production Company and MarkWest Energy Appalachia, L.L.C., as amended by the parties thereto and Seller on November 16, 2007;

(vi)Firm Gas Processing Agreement (Dwale) dated September 23, 2004 by and between EQT Production Company and MarkWest Hydrocarbon, Inc., as amended by the parties thereto on November 16, 2007;

(vii)Firm Gas Processing Agreement (Non-Dwale) dated September 23, 2004 by and between EQT Production Company and MarkWest Hydrocarbon, Inc., as amended by the parties thereto on November 16, 2007; and

(viii)Guaranty dated March 26, 2002 by and between EQT Production Company and MarkWest Energy Partners, L.P., as amended by the parties thereto and Seller on November 16, 2007.

(nn)“Material Contract” means any Assigned Contract that:

(i)involves obligations of, or payments to or from, Seller (or one of its Affiliates) in excess of **;

(ii)is for the purchase, sale, gathering, compression, collection, processing, blending, treating, dehydration, handling, fractionation, storage, metering, measurement, balancing or transportation of natural gas, NGLs or other hydrocarbons;

(iii)constitutes a pipeline interconnect or facility operating or maintenance agreement;

(iv)restricts Seller (or one of its Affiliates) from freely engaging in any business or competing anywhere;

(v)imposes a Lien on any Asset;

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(vi)constitutes a lease (whether capital or operating) under which Seller (or Affiliate thereof) is the lessor or the lessee of real, immovable, personal or movable property, which lease (1) involves any Real Property Interest or (2) involves an annual base rental of more than **;

(vii)has the primary purpose of indemnifying a third Person;

(viii)constitutes a partnership agreement, joint venture agreement or similar agreement or involving a sharing of profits, losses, costs, or Liabilities by Seller with any other Person; or

(ix)relates to settlement, conciliation and other similar agreements relating to any actual or threatened Proceeding, the performance of which will involve payment on or after the Closing Date of consideration in excess of ** or will, on or after the Closing Date impose (or continue to impose) any injunctive or similar equitable relief on the Assets.

(oo)“NGL” means propane, iso-butane, normal butane, iso-pentane, normal pentane, hexanes and any other liquid hydrocarbon or any mixtures thereof, including incidental methane and incidental ethane, but excluding liquefied methane.

(pp)“NGL Delivery Point” has the meaning set forth in the Gas Processing Agreement.

(qq)“NGL Inventory Value”  means, with respect to each NGL, an amount equal to the product of: (x) the volume of such NGL; and (y) the Applicable Index Price for such NGL.

(rr)“Owned Real Property” means all parcels of land described in Exhibits A-3-1, A-3-2, A-3-3, and A-3-4, together with all buildings, improvements and fixtures located thereon and all easements, rights of way, servitudes, tenements, hereditaments, appurtenances, privileges and other rights and interests appurtenant thereto owned by Seller.

(ss)“Other Transaction Documents” means the Gas Processing Agreement, the Big Sandy Shared Services Agreement, the NGL Exchange Agreement, the Amendments, the Conveyances and the Assignment.

(tt)“Permitted Encumbrance” means, with respect to an Asset, any or all of the following:

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(i)statutory Liens for property Taxes or assessments not yet delinquent, or if delinquent, being contested by appropriate actions and for which appropriate accruals have been established;

(ii)mechanic’s, materialmen’s, repairmen’s, employee’s, contractor’s, operator’s or other similar Liens or charges arising by operation of Law, in the ordinary course of business for amounts not yet delinquent (including any amounts being withheld as provided by Law);

(iii)any Liens affecting the Assets that are (a) assumed, bonded or paid by Buyer pursuant to this Agreement or (b) otherwise discharged, in each case at or prior to Closing;

(iv)with respect to pipeline, utility and similar easements, all rights of any Governmental Authority to regulate the Assets, immaterial defects and irregularities in title, encumbrances, exceptions, Liens and other matters that, singularly or in the aggregate, will not materially interfere with the ownership, use, value, operation or maintenance of the Assets to which they pertain or reduce the share of revenues or increase the share of costs with respect to the Assets that, after the Closing, the Buyer will be entitled to receive or must be borne by the Buyer;

(v)the terms and conditions of the Permits listed on Exhibit A-4 and the Contracts Exhibit A-5;

(vi)the items set forth in Section 2.4 of the Disclosure Schedule; and

(vii)all rights to consent, by required notices to, filings with, or other actions by Governmental Authorities in connection with the sale or conveyance of easements, rights of way, licenses, facilities or interests therein if they are customarily obtained subsequent to the sale or conveyance.

(uu)“Person” means any individual, corporation, partnership, limited liability company, trust, estate, Governmental Authority or any other entity.

(vv)“Plant Products” means the NGLs that are separated, extracted, recovered or condensed, and saved, from the gas processed in the Processing Facilities.

(ww)“Pre-Closing Period” means, with respect to the Assets, any Tax period ending on or prior to the Closing Date.

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(xx)“Proceeding” means any litigation, action, suit, claim, demand, investigation, examination, regulatory request for information, review or other judicial or administrative proceeding, at law or in equity, or any arbitration or other dispute resolution, before or by any Governmental Authority, or any order, judgment, decree, injunction, award or ruling issued thereunder.

(yy)“Propak License Agreement” means that certain license agreement to be executed and delivered by Propak and Buyer on the Closing Date.

(zz)“Ranger NGL Pipeline” means the existing NGL pipeline described in Part II of Exhibit A-1 (such existing portion, the “Ranger I NGL Pipeline”), together with the “Ranger II NGL Pipeline” (as defined in the NGL Exchange Agreement) to be completed by Buyer pursuant to the NGL Exchange Agreement, including all rights of ways, easements, and other real property rights, and all inventories of pipeline, valves, meters, cathodic protection equipment, related materials and supplies, whether ordered or already delivered or in possession of Seller, which will be necessary or used in connection with  transporting NGLs (upon completion) from the Processing Facilities to the Trans-Sandy Interconnect.

(aaa)“Ranger Truck Terminal” means the truck unloading and pipeline injection station located at the terminus of the Ranger I NGL Pipeline, located near the Kentucky and West Virginia state line.

(bbb)“Release” means any presence, releasing, depositing, spilling, leaking, pumping, pouring, placing, emitting, discarding, abandoning, emptying, discharging, migrating, injecting, escaping, leaching, dumping, or disposing into the Environment.

(ccc)“Remediation” means any investigation, clean-up, removal action, remedial action, restoration, repair, abatement, response action, corrective action, monitoring, sampling and analysis, installation, reclamation, closure, or post-closure in connection with the suspected, threatened or actual Release of Hazardous Materials.

(ddd)“Retained Liabilities” means any responsibility for any Liabilities of Seller and its Subsidiaries other than the Assumed Liabilities, including the following (i) any Liability arising out of or relating to the Excluded Assets, (ii) any of Seller’s Liabilities for expenses and fees incident to or arising out of the negotiation, preparation, approval or authorization of this Agreement or the consummation (or preparation for the consummation) of the transactions contemplated hereby (including all attorneys’, accountants and fees), (iii) any Liability related to any employee of Seller (including, but not limited to, any retention, stay bonus or similar agreements entered into prior to the Closing Date

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in connection with or related to the transactions contemplated hereby), except to the extent such liability relates to a Hired Employee and is expressly assumed by the Buyer pursuant to this Agreement, (iv) any obligation or liability under any intercompany accounts payable to or intercompany obligations among the Seller and its Affiliates, including those relating to the Assets, (v) any Liability in respect of indebtedness of the Seller, except for trade debt relating to Assigned Contracts, (vi) any Liability in respect of income Taxes of Seller, (vii) any Liability relating to any legal action, proceeding, claim or investigation arising out of or in connection with any breach of any Assumed Contract by Seller occurring prior to the Effective Time and (viii) any Liability arising out of or relating to the matters set forth on Section 2.6 of the Disclosure Schedule; provided, however, that Retained Liabilities in respect of matter (1) “United States Department of Transportation Notice of Proposed Violation, Docket No. CPF 2-2006-5001” (the “Ivel NOPV”) on Section 2.6 of the Disclosure Schedule shall be limited to any monetary penalty imposed on Seller or its Affiliates.

(eee)“Seller Material Adverse Effect” means any change, effect, circumstance, condition, event, occurrence, state of facts, or development that is or could reasonably be expected to be, individually or together with any other change, effect, circumstance, condition, event, occurrence, state of facts, or development, material and adverse to the Assets, taken as a whole, but in each case shall not include the effect of events, changes and circumstances relating to (i) the United States economy generally and (ii) the industries and markets in which the business comprising the Assets operates, to the extent they do not have a disproportionately adverse affect on the Assets.

(fff)“Siloam Fractionation Plant” has the meaning set forth in the Gas Processing Agreement.

(ggg)“Straddle Period” means any Tax period that begins before and ends after the Closing Date.

(hhh)“Tax” or “Taxes” means (a) any and all taxes, fees, levies, duties, tariffs, imposts and other charges of any kind, imposed by any Governmental Authority or taxing authority, including taxes or other charges on, measured by, or with respect to income, franchise, windfall or other profits, gross receipts, property, sales, use, capital stock, payroll, employment, social security, workers’ compensation, unemployment compensation or net worth; taxes or other charges in the nature of excise, withholding, ad valorem, stamp, transfer, value-added or gains taxes; license, registration and documentation fees; and custom’s duties, tariffs and similar charges; (b) any liability for the payment of any amounts of the type described in (a) as a result of being a person required by Law to withhold or collect taxes imposed on another person; (c) any liability for the payment of amounts of the type described in (a) or (b) as a result of being a

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transferee of, or a successor in interest to, any person or as a result of an express or implied obligation to indemnify any person; and (d) any and all interest, penalties, additions to tax and additional amounts imposed in connection with or with respect to any of the foregoing amounts.

(iii)“Tax Authority” means any Governmental Authority having jurisdiction over the payment or reporting of any Tax.

(jjj)“Tax Return” means any return, statement, declaration, form, report, claim for refund or credit, or information return or other documentation (including any additional or supporting material and any amendments or supplements) filed by Seller with a Governmental Authority with respect to or in connection with the calculation, determination, assessment or collection of any Taxes.

(kkk)“Trans-Sandy Interconnect” means the interconnect point of the Ranger NGL Pipeline with the Trans-Sandy NGL Pipeline near Ranger, West Virginia.

(lll)Trans-Sandy NGL Pipeline” means the NGL pipeline currently owned by Buyer or one of its Affiliates capable of transporting NGLs to the Siloam Fractionation Plant

(mmm)“US GAAP” means, at any time, generally accepted accounting principles in the United States in effect as of such time.

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IN WITNESS WHEREOF, each of the undersigned has caused this Agreement to be duly signed as of the date first above written.

EQT GATHERING, LLC
By:	/s/  M. Elise Hyland
	Name:  M. Elise Hyland
	Title:    Chief Commercial Officer
MARKWEST ENERGY APPALACHIA, L.L.C.
By:	/s/  Frank Semple
	Name:  Frank Semple
	Title:    President & CEO

Signature Page to Purchase and Sale Agreement

EXHIBIT A-1

PROCESSING FACILITIES AND RANGER NGL PIPELINE

PART I

Langley Plant #1:  100 MMCf/d cryogenic plant: Propak Systems ltd. Licensed**

Langley Plant #2:  70 MMCf/d refrigeration plant: JT / Mechanical refrigeration plant**

Big Sandy compression inlet pressure range is 350-450 psig.

Interconnect to EQT gathering line (to Columbia gas transmission (TCO) Beavercreek interconnect) maximum allowable operating pressure is 425 psig.

PART II

Ranger Pipeline (existing West Virginia Portion):  from the Ranger Trucking Terminal mov 6 location, is a 27 mile, 8” steel natural gas liquids pipeline. Maximum allowable operating pressure 2160 psig. The interconnect is with MarkWest at their Trans-Sandy pipeline.

Ranger Trucking Terminal: is located on the Ranger pipeline, near mov 6. **

Ranger Stock Items: [see attached]

**

[5 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EXHIBIT A-2

PERSONAL PROPERTY

**

[5 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EXHIBIT A-3

REAL PROPERTY INTERESTS

[see attached]

**

[61 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EXHIBIT A-4

PERMITS

**

[4 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EXHIBIT A-5

ASSIGNED CONTRACTS

[see attached]

**

[6 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EXHIBIT A-6

RADIO LICENSES

**

EXHIBIT B

EXCLUDED ASSETS

[see attached]

**

[34 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

DISCLOSURE SCHEDULES

TO THE PURCHASE AND SALE AGREEMENT

BY AND BETWEEN

EQT GATHERING, LLC

AND

MARKWEST ENERGY APPALACHIA, L.L.C.

DATED AS OF January 3, 2011

Capitalized terms used in this Disclosure Schedule (the “Schedule”) and not otherwise defined herein shall have the meanings given to such terms in the Purchase and Sale Agreement by and between EQT Gathering, LLC and MarkWest Energy Appalachia, L.L.C. dated as of January 3, 2011 (the “Agreement”).

Inclusion of information herein shall not be construed as an admission or acknowledgment, in and of itself, that such information is (i) required by the terms of the Agreement to be disclosed, (ii) material to the Assets or the Seller or (iii) has or would have a Seller Material Adverse Effect.

Matters disclosed in this Schedule under any particular reference to a section of Article II of the Agreement shall be deemed to be disclosed under all other sections of the Agreement for which the applicability of such information and disclosure is readily apparent.

INDEX

Section 2.3(b)	Real Property Consents
Section 2.4(a)	Title Matters
Section 2.4(f)	Condition of Certain Assets
Section 2.6	Litigation
Section 2.11	Taxes
Section 2.12(a)-(f)	Environmental Matters
Section 2.13	Intellectual Property Licenses
Section 6.1	Conduct of Business
Section 6.8	Purchase Orders
Section 10.9	Knowledge Individuals

**

[15 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

EX-10.2

Exhibit 10.2

SPECIFIC TERMS IN THIS EXHIBIT HAVE BEEN REDACTED BECAUSE CONFIDENTIAL TREATMENT FOR THOSE TERMS HAS BEEN REQUESTED. THE REDACTED MATERIAL HAS BEEN SEPERATELY FILED WITH THE SECURITIES AND EXCHANGE COMMISSION, AND THE TERMS HAVE BEEN MARKED AT THE APPROPRIATE PLACE WITH TWO ASTERISKS (**).

February 1, 2011

MarkWest Energy Appalachia, L.L.C.
1515 Arapahoe Street
Tower 1, Suite 1600

Denver, CO 808202
Attention:

Re:Purchase and Sale Agreement (the “PSA”), dated as of January 3, 2011, by and between EQT Gathering, LLC, as Seller, and MarkWest Energy Appalachia, L.L.C., as Buyer

Ladies and Gentlemen:

This letter (this “Letter Agreement”) memorializes our agreement with respect to the matters discussed below.  Capitalized terms used but not otherwise defined herein shall have the meaning given to those terms in the PSA.

In accordance with Section 10.1 of the PSA, the Parties hereby agree that this Letter Agreement shall amend the PSA as follows:

1.Effective Time.  Section 11.1(s) of the PSA is amended to replace the reference to “12:00 A.M.” with a reference to “10:00 A.M.” in its entirety.

2.Exhibits to PSA.

a.Exhibit A-2 to the PSA is amended and restated in its entirety in the form attached hereto as Schedule 2(a) to add certain pieces of equipment.

b.Exhibit A-3 to the PSA is amended and restated in its entirety in the form attached hereto as Schedule 2(b) to add certain fee tracts and rights-of-way and otherwise correct data related to certain rights-of-way, access roads and valve sites.

c.Exhibit A-4 to the PSA is amended to add one railroad permit as identified on Schedule 2(c).

d.Exhibit A-5 to the PSA is amended and restated in its entirety in the form attached hereto as Schedule 2(d) to remove certain Assigned Purchase Orders that have been fully performed by Seller (or one of its Affiliates) prior to the date hereof.

e.Exhibit A-6 to the PSA is amended and restated in its entirety in the form attached hereto as Schedule 2(e) to correct the call sign for the Radio License referenced therein.

3.EQT Processing Facilities Agreement.

a.In the event that the ** Real Property Consent(s) described in Section 2.3(b) of the Disclosure Schedules to the PSA are not obtained prior to Closing, Seller will provide MarkWest Ranger Pipeline Company, L.L.C. (“MarkWest Ranger”), to the commercially reasonable extent possible, with the rights, benefits and burdens of the portion of the Ranger NGL Pipeline that is not conveyed to MarkWest Ranger at the Closing as a consequence of failing to obtain such consent(s). The Parties agree that this provision constitutes an “EQT Processing Facilities Agreement” with respect to such portion of the Ranger NGL Pipeline as contemplated by Section 1.8(c) of the PSA.

b.When the ** Real Property Consent(s) are obtained, Seller shall convey the applicable portions of the Ranger NGL Pipeline pursuant to the terms of the PSA.

4.Estimated Closing Adjustment.  Buyer and Seller acknowledge and have agreed upon the Closing Adjustment attached as Schedule 4 and prepared in accordance with Section 1.3(b) of the PSA, setting forth the Estimated Purchase Price for the Assets to be purchased, the amount of each adjustment to the Purchase Price and the calculation of each such adjustment used to determine each such amount.

5.Langley Inventory.  Notwithstanding anything to the contrary in the PSA, within 30 days following the Closing Date, Buyer and Seller will use commercially reasonable efforts to perform an inventory of the equipment located at the Processing Facilities and identify those pieces of equipment as primarily related to the Assets or the Excluded Assets.  Upon completion of such inventory, as mutually agreed, Seller will retain such equipment that is related to the Excluded Assets and/or convey to Buyer at no additional cost to Buyer the equipment that is related to the Assets on the same terms and conditions as set forth in that certain Assignment, Bill of Sale and Assumption Agreement, by and between Seller and Buyer, dated as of February 1, 2011.

6.Transition Services.  Pursuant to Section 6.12 of the PSA, Buyer requests that following the Closing, Seller assist with certain transition services related to the Ranger Truck Terminal and the Ranger NGL Pipeline.  Specifically, Buyer requests that immediately following the Closing, Seller will continue to perform the monitoring and remote pump/valve operations of both the Ranger Truck Terminal and the Ranger NGL Pipeline (the “Transition Services”) to the same extent as such activities were performed by Seller or its Affiliates prior to the Closing.  Seller agrees that it will direct any field call-outs to personnel appointed by the Buyer.  Buyer and Seller agree that Seller will provide the Transition Services until such time as Buyer provides written notification to Seller that it is prepared to assume the Transition Services and Buyer and Seller shall mutually agree on a date to transfer performance of the Transition Services, provided, however, in no event shall the performance of the Transition Services by Seller last for more than 120 days.

7.All references to the PSA shall be considered references to the PSA as modified by this Letter Agreement.  This Letter Agreement may be executed in counterparts, each of which shall be deemed an original instrument, but all such counterparts together shall constitute but one agreement.  The PSA, as amended herein, and the documents to be executed thereunder

2

and the Exhibits and Schedules attached thereto, constitute the entire agreement among the Parties pertaining to the subject matter hereof, and supersede all prior agreements, understandings, negotiations and discussions, whether oral or written, of the Parties pertaining to the subject matter hereof.  In the event of a conflict between the terms of this Letter Agreement and the terms of the PSA, the terms of this Letter Agreement shall control.

This Letter Agreement and the legal relations between the parties hereto shall be governed by and construed in accordance with the Laws of the Commonwealth of Pennsylvania, without regard to principles of conflicts of Laws that would direct the application of the Laws of another jurisdiction.

This Letter Agreement may be amended or modified only by an agreement in writing signed by Seller and Buyer and expressly identified as an amendment or modification.  Except as amended by this Letter Agreement, the PSA remains in full force and effect in accordance with its terms.

[The remainder of the page intentionally left blank.]

3

Please confirm your agreement with the terms and conditions of this Letter Agreement by executing a copy in the space specified below.

		Very truly yours,
		EQT GATHERING, LLC
		By:	/s/ M. Elise Hyland
		Name:	M. Elise Hyland
		Title:	Chief Commercial Officer
MARKWEST ENERGY APPALACHIA, L.L.C.
By:	/s/ Frank M. Semple
Name:	Frank M. Semple
Title:	President and Chief Executive Officer

cc: MarkWest Energy Appalachia, L.L.C.

1515 Arapahoe Street

Tower 1, Suite 1600

Denver, CO 80202

Attention:  General Counsel

Facsimile: (303) 925-9308

Hogan Lovells US LLP

One Tabor Center

1200 Seventeenth St., Ste. 1500

Denver, CO 80202

Facsimile: (303) 899-7333

Attention: George Hagerty

EQT Gathering, LLC

EQT Plaza

625 Liberty Avenue, Suite 1700

Telephone: (412) 553-5700

Facsimile: (412) 553-7781

Attention:  General Counsel

Baker Botts LLP

One Shell Plaza

910 Louisiana Street

Houston, TX  77002

Facsimile: (713) 229-7778

Attention:  Hugh Tucker

Schedule 2(a)

Personal Property

**

[5 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

Schedule 2(b)

Real Property Interests

**

[73 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

Schedule 2(c)

Permits

Road and Railroad Permits:

**

Schedule 2(d)

Assigned Contracts

[see attached]

**

[3 pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

Schedule 2(e)

Radio Licenses

**

Schedule 4

Estimated Closing Adjustment

This Estimated Closing Adjustment is delivered by EQT Gathering, LLC pursuant to Section 1.3(b) of the Purchase and Sale Agreement, dated as of January 3, 2011, by and between EQT Gathering, LLC and MarkWest Energy Appalachia, L.L.C. (the “PSA”).  Capitalized terms used but not defined herein have the meanings set forth in the PSA.

**

EX-31.1

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Exhibit 31.1

CERTIFICATION

I, Frank M. Semple, certify that:

1.

I have reviewed this quarterly report on Form 10-Q of MarkWest Energy Partners, L.P.

2.

Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

3.

Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report.

4.

The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f), for the registrant and have:

a)

Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)

Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)

Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)

Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.

The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of registrant's board of directors (or persons performing the equivalent function):

a)

All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b)

Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: May 9, 2011 By: /s/ FRANK M. SEMPLE
Frank M. Semple
Chairman, President and Chief Executive Officer
(Principal Executive Officer)

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Exhibit 31.1

CERTIFICATION

EX-31.2

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Exhibit 31.2

CERTIFICATION

I, Nancy K. Buese, certify that:

1.

I have reviewed this quarterly report on Form 10-Q of MarkWest Energy Partners, L.P.

2.

Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

3.

Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report.

4.

The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f), for the registrant and have:

a)

Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)

Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)

Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)

Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.

The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of registrant's board of directors (or persons performing the equivalent function):

a)

All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b)

Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: May 9, 2011 By: /s/ NANCY K. BUESE
Nancy K. Buese
Senior Vice President & Chief Financial Officer
(Principal Financial Officer and Principal
Accounting Officer)

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Exhibit 31.2

CERTIFICATION

EX-32.1

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Exhibit 32.1

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Quarterly Report of MarkWest Energy Partners, L.P. (the "Partnership"), on Form 10-Q for the period ending March 31, 2011, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Frank M. Semple, Chief Executive Officer of the General Partner of the Partnership, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)

The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and



(2)

The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Partnership.

Date: May 9, 2011 By: /s/ FRANK M. SEMPLE
Frank M. Semple
Chairman, President and Chief Executive Officer
(Principal Executive Officer)

        This certification is being furnished solely pursuant to 18 U.S.C. Section 1350 and is not being filed as part of the Report or as a separate disclosure document. This certification shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to liability under that section. This certification shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act except to the extent this Exhibit 32.1 is expressly and specifically incorporated by reference in any such filing.

        A signed original of this written statement required by Section 906 has been provided to the Partnership and will be retained by the Partnership and furnished to the Securities and Exchange Commission or its staff upon request.

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Exhibit 32.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

EX-32.2

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Exhibit 32.2

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Quarterly Report of MarkWest Energy Partners, L.P. (the "Partnership") on Form 10-Q for the period ending March 31, 2011, as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Nancy K. Buese, Chief Financial Officer of the General Partner of the Partnership, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)

The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and



(2)

The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of the Partnership.

Date: May 9, 2011 By: /s/ NANCY K. BUESE
Nancy K. Buese
Senior Vice President & Chief Financial Officer
(Principal Financial Officer and
Principal Accounting Officer)

        This certification is being furnished solely pursuant to 18 U.S.C. Section 1350 and is not being filed as part of the Report or as a separate disclosure document. This certification shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to liability under that section. This certification shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act except to the extent this Exhibit 32.2 is expressly and specifically incorporated by reference in any such filing.

        A signed original of this written statement required by Section 906 has been provided to the Partnership and will be retained by the Partnership and furnished to the Securities and Exchange Commission or its staff upon request.

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Exhibit 32.2

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002