CONTRIBUTION AGREEMENT

QuickLinks -- Click here to rapidly navigate through this document

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 (**).

Execution Version

CONTRIBUTION AGREEMENT

BY AND AMONG

MARKWEST LIBERTY GAS GATHERING, L.L.C.,

M&R MWE LIBERTY, LLC,

AND

MARKWEST LIBERTY MIDSTREAM & RESOURCES, L.L.C.

TABLE OF CONTENTS

i

ii

iii

CONTRIBUTION AGREEMENT

         THIS CONTRIBUTION AGREEMENT , dated as of January 22, 2009, is entered into by and among MarkWest Liberty Gas Gathering, L.L.C., a Delaware limited liability company (" MWE Liberty "), M&R MWE Liberty, LLC, a Delaware limited liability company (" NGPMR "), and MarkWest Liberty Midstream & Resources, L.L.C., a Delaware limited liability company (the " Company "). The parties to this Agreement are collectively referred to herein as the " Parties ."

R E C I T A L S

        WHEREAS, MWE Liberty has formed the Company, pursuant to the Act, for the purpose of engaging in the natural gas midstream business, including, but not limited to, natural gas gathering and processing, and the natural gas liquids processing, fractionation, transportation, storage and marketing business within the Area of Mutual Interest and certain other purposes (the " Business ");

        WHEREAS, at the Closing MWE Liberty and NGPMR (the " Members ") shall execute and agree to that certain Amended and Restated Limited Liability Company Agreement of the Company (the " Company Operating Agreement ") in the form attached hereto as Exhibit C , which Company Operating Agreement shall become effective at the Closing;

        WHEREAS, at the Closing MWE Liberty, MarkWest Hydrocarbon, Inc. and the Company shall execute and agree to that certain Services Agreement (the " Services Agreement ") in the form attached hereto as Exhibit D , which Services Agreement shall become effective at the Closing;

        WHEREAS, subject to the terms and conditions of this Agreement, NGPMR desires to contribute to the Company, and the Company desires to accept from NGPMR, certain cash consideration in exchange for all of the Class A Interests; and

        WHEREAS, subject to the terms and conditions of this Agreement, MWE Liberty desires to contribute, convey, assign and transfer to the Company, and the Company desires to accept from MWE Liberty, all of MWE Liberty's right, title and interest in and to the Assets in exchange for all of the Class B Interests and the assumption of certain liabilities by the Company.

A G R E E M E N T S

        NOW, THEREFORE, in consideration of their mutual undertakings and agreements hereunder, the Parties undertake and agree as follows:

ARTICLE 1
DEFINITIONS; INTERPRETATION

        Section 1.1     Definitions .    Capitalized terms used in this Agreement but not defined in the body hereof shall have the meanings ascribed to them in Exhibit A .

        Section 1.2     Headings; References; Interpretation .    In this Agreement, unless a clear contrary intention appears: (a) the singular includes the plural and vice versa; (b) reference to a person includes such Person's successors and assigns but, in the case of a Party, only if such successors and assigns are permitted by this Agreement, and reference to a Person in a particular capacity excludes such Person in any other capacity; (c) reference to any gender includes each other gender; (d) reference to any agreement (including this Agreement), document or instrument means such agreement, document, or instrument as amended or modified and in effect from time to time in accordance with the terms thereof and, if applicable, the terms of this Agreement; (e) reference to any Section or Article means such Section or Article of this Agreement, and references in any Section or Article or definition to any clause means such clause of such Section, Article or definition; (f) "hereunder," "hereof," "hereto" and words of similar import are references to this Agreement as a whole and not to any particular provision hereof; and (g) the word "or" is not exclusive, and the word "including" (in its various forms) means including without limitation. Section titles and headings in this Agreement are inserted for convenience

of reference only and are not intended to be a part of, or to affect the meaning or interpretation of, this Agreement.

ARTICLE 2
CONTRIBUTIONS, ASSUMED LIABILITIES AND CLOSING

        Section 2.1     Contributions and Payments .    Subject to the terms and conditions of this Agreement, at the Closing, the following contributions, equity issuances and payments shall be made:

        (a)   NGPMR shall contribute $50,000,000.00 to the Company in immediately available funds in exchange for all of the Class A Interests. In its capacity as a holder of such interests, NGPMR shall have the obligations set forth in the Company Operating Agreement with respect to a Class A Member to contribute additional capital to the Company, but shall have no other obligation to contribute any additional capital to the Company. !

        (b)   MWE Liberty shall grant, contribute, bargain, convey, assign, transfer, set over and deliver to the Company, its successors and assigns, and for its and their own use forever, all of MWE Liberty's right, title and interest in and to the Assets in exchange for all of the Class B Interests. In its capacity as a holder of such interests, MWE Liberty shall have the obligations set forth in the Company Operating Agreement with respect to a Class B Member to contribute additional capital to the Company, but shall have no other obligation to contribute any additional capital to the Company. The term " Assets " shall mean (i) all of the assets owned by MWE Liberty, including the natural gas gathering systems described in Exhibit B attached hereto, together with all natural gas gathering and processing and natural gas liquids processing, fractionation, transportation, storage and marketing plants and facilities constituting a part thereof or related thereto, and all easements, rights of way, privileges, franchises, tracts of land, surface leases, other interests in land, pipelines, equipment, permits, licenses, contract rights and personal property constituting a part thereof or necessary for the ownership and operation thereof including the easements, rights of way, permits and other instruments referenced in Exhibit B and (ii) all of the assets owned by Affiliates of MWE Liberty that are related exclusively to the Business within the Area of Mutual Interest, but in any event, excluding any and all amounts payable by Range Resources-Appalachia, LLC pursuant to Section 4.3(d) of that certain Interim Gas Processing Agreement dated March 5, 2008, between MarkWest Energy Appalachia, L.L.C. and Range Resources-Appalachia, LLC, for procuring, constructing and installing the interim plant prior to January 1, 2008 and representing 115% of all Installation Costs (as defined therein) incurred in the procurement, construction and installation of the interim plant (the " Excluded Assets "). The Excluded Assets shall be retained by MWE Liberty and its Affiliates and shall not be considered Assets hereunder.

        (c)   The Company shall pay to MWE Liberty in immediately available funds the amount of any **; provided that any such ** by MWE Liberty after the date hereof shall be consistent with Section 6.8 .

        Section 2.2     Assumption of Liabilities .    As part of the consideration for the contribution of the Assets by MWE Liberty to the Company, effective as of the Closing, the Company will assume and agree to duly and timely pay, perform and discharge, pursuant to the Assignment and Assumption, all of the liabilities and obligations of any kind whatsoever of MWE Liberty arising from or relating to the Assets, whether known or unknown, liquidated or contingent, and regardless of whether the same are deemed to have arisen, accrued or are attributable to periods prior to, on or after the Closing Date, including, but not limited to, obligations and liabilities of MWE Liberty: (a) concerning the use, ownership, management or operation of the Assets, (b) under or relating to any contracts, agreements, Permits and instruments existing as of the Closing Date by which the Assets are bound or subject or that relate to or are otherwise applicable to the Assets (other than obligations of MWE Liberty under

2

the Transaction Documents) and (c) which are Disclosed Liabilities, (all of the liabilities and obligations described in this Section 2.2 are collectively referred to as the " Assumed Liabilities "); provided, however , that the Company does not assume (and Assumed Liabilities shall not include) any costs or expenses included within the amount of MWE Liberty's initial capital contribution to the Company.

        Section 2.3     Closing .    Subject to the terms and conditions of this Agreement, the closing of the transactions contemplated by this Agreement (the " Closing ") shall take place at the offices of Vinson & Elkins LLP, First City Tower, 1001 Fannin Street, Suite 2500, Houston, Texas 77002 on the second Business Day after all of the conditions precedent set forth in Article 7 have been satisfied, or if permissible, waived, or at such other place, time and date as is agreed to in writing by the Parties (the " Closing Date "). The Closing will be deemed effective as of 11:59 p.m., Houston, Texas time on the Closing Date.

        Section 2.4     Closing Deliveries .    

        (a)     NGPMR Deliveries .    At the Closing, NGPMR will execute and deliver, or cause to be executed and delivered, to the other Parties, as applicable, each of the following documents, where the execution or delivery of documents is contemplated, and will take or cause to be taken the following actions, where the taking of action is contemplated:

          (i)  a certificate of the Secretary of State of the State of Delaware, dated not more than five days prior to the Closing Date, as to the existence and good standing of NGPMR;

         (ii)  a certificate of an officer of NGPMR providing the following documents and certifying that each is a true and correct copy: (A) the Organizational Documents of NGPMR and (B) resolutions of NGPMR's governing body authorizing the transactions contemplated hereby (including designation of the Persons authorized to execute this Agreement on behalf of NGPMR and the Transaction Documents to which it is a party);

        (iii)  a duly executed counterpart of the Company Operating Agreement; and

        (iv)  a certificate of an officer of NGPMR, dated as of the Closing Date, certifying that all of the conditions set forth in Sections 7.1(a) and 7.3(a) have been satisfied.

        (b)     MWE Liberty Deliveries .    At the Closing, MWE Liberty will execute and deliver, or cause to be executed and delivered, to the other Parties, as applicable, each of the following documents, where the execution or delivery of documents is contemplated, and will take or cause to be taken the following actions, where the taking of action is contemplated:

          (i)  a certificate of the Secretary of State of the State of Delaware, dated not more than five days prior to the Closing Date, as to the existence and good standing of MWE Liberty;

         (ii)  a certificate of an officer of MWE Liberty providing the following documents and certifying that each is a true and correct copy: (A) the Organizational Documents of MWE Liberty and (B) resolutions of MWE Liberty's governing body authorizing the transactions contemplated hereby (including designation of the Persons authorized to execute this Agreement on behalf of MWE Liberty and the Transaction Documents to which it is a party);

        (iii)  a duly executed counterpart of the Company Operating Agreement;

        (iv)  a duly executed counterpart of the Services Agreement;

         (v)  counterparts of the Bill of Sale, Assignment and Assumption Agreement, in substantially the form attached as Exhibit E hereto (the " Assignment and Assumption "); and

        (vi)  a certificate of an officer of MWE Liberty, dated as of the Closing Date, certifying that all of the conditions specified in Section 7.1(e) and Section 7.2(a) have been satisfied.

3

        (c)     Company Deliveries .    At the Closing, MWE Liberty will cause the Company to execute and deliver:

          (i)  a certificate of the Secretary of State of the State of Delaware, dated not more than five days prior to the Closing Date, as to the existence and good standing of the Company;

         (ii)  a copy of the Certificate of Formation of the Company certified by the Secretary of State of the State of Delaware;

        (iii)  a duly executed counterpart of the Assignment and Assumption; and

        (iv)  a duly executed counterpart of the Services Agreement;

        The transactions described above, together with the issuance and sale of the Class A Interests and the Class B Interests pursuant to this Agreement and the entry into the Company Operating Agreement, are referred to herein as the " Transactions ." The " Transaction Documents " shall mean this Agreement, the Company Operating Agreement, and the Services Agreement.

ARTICLE 3
REPRESENTATIONS AND WARRANTIES OF MWE LIBERTY

        MWE Liberty hereby makes the following representations and warranties to the Company and NGPMR:

        Section 3.1     Organization; Qualification .    Each of MWE Liberty and the Company is a limited liability company duly formed, validly existing and in good standing under the laws of the State of Delaware and has all requisite limited liability company power and authority to own, lease and operate its properties and to carry on its business, and is duly qualified, registered or licensed to do business as a foreign limited liability company and is in good standing in each jurisdiction in which the property owned, leased or operated by it or the nature of the business conducted by it makes such qualification necessary, except where the failure to be so duly qualified, registered or licensed and in good standing would not have or be reasonably expected to have, individually or in the aggregate, a Material Adverse Effect.

        Section 3.2     Authority; Enforceability .    

        (a)   Each of MWE Liberty and the Company has the requisite limited liability company power and authority to execute and deliver the Transaction Documents to which it is a party, and to consummate the Transactions. The execution and delivery by MWE Liberty and the Company of the Transaction Documents to which either of them is a party, and the consummation by MWE Liberty and the Company of the Transactions, have been duly and validly authorized by MWE Liberty and/or the Company, as applicable, and no other limited liability company proceedings on the part of MWE Liberty or the Company are necessary to authorize the Transaction Documents or to consummate the Transactions.

        (b)   Each of the Transaction Documents to which MWE Liberty or the Company is a party has been (or will be, in the case of Transaction Documents to be delivered at the Closing) duly executed and delivered by MWE Liberty and/or the Company, as applicable, and, assuming the due authorization, execution and delivery by the other parties thereto, each Transaction Document constitutes (or will constitute, in the case of Transaction Documents to be delivered at the Closing) the valid and binding agreement of MWE Liberty and the Company, and is enforceable against MWE Liberty and/or the Company, as applicable, in accordance with its terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors' rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law).

4

        Section 3.3     No Violation; Consents and Approvals .    Except as set forth on Schedule 3.3 :

        (a)   The execution, delivery and performance of the Transaction Documents by MWE Liberty and the Company and the consummation by MWE Liberty and the Company of the Transactions do not and will not: (i) result in any breach of any provision of the organizational, governing or charter documents, as amended, of MWE Liberty or the Company; (ii) constitute a default (or an event that with notice or lapse of time or both would give rise to a default) under, or give rise to any right of termination, cancellation, amendment or acceleration (with or without notice, lapse of time or both) under any of the terms, conditions or provisions of any contract, note, bond, mortgage, indenture, license, agreement or other instrument or obligation to which MWE Liberty or the Company is a party or by which any of the Assets is bound or affected, except to the extent that such default, termination, amendment, acceleration or cancellation right (A) would not have or be reasonably expected to have, individually or in the aggregate, a Material Adverse Effect or (B) results from obtaining the Miscellaneous Consents after the Closing pursuant to Section 6.5 ; (iii) result in a violation of any law, statute, rule, regulation, order, judgment, injunction, decree or other restriction of any Governmental Authority to which MWE Liberty or the Company is subject (including federal and state securities laws and regulations) or by which any of the Assets is bound or affected except as may result from obtaining the Miscellaneous Consents after the Closing pursuant to Section 6.5 ; or (iv) result in the creation or imposition of any lien, charge or encumbrance upon any of the Assets, except for Permitted Liens or as may result from obtaining the Miscellaneous Consents and contractual consents listed on Schedule 3.3 after the Closing pursuant to Section 6.5 .

        (b)   No declaration, filing or registration with, or notice to, or authorization, consent or approval of, any Governmental Authority or other third party is necessary for the consummation by MWE Liberty or the Company of the Transactions contemplated by the Transaction Documents, other than such declarations, filings, registrations, notices, authorization, consents or approvals that have been or will be obtained or made prior to the Closing and other than the Miscellaneous Consents that may be obtained after the Closing pursuant to Section 6.5 .

        (c)   No consents are required under the Indentures to permit the consummation of the Transactions.

        Section 3.4     Capitalization .    

        (a)   Except for the Company, MWE Liberty does not (i) own, directly or indirectly, any capital stock, equity interests or other securities of any Person, or (ii) have any Subsidiaries.

        (b)   Except as set forth on Schedule 3.4(b) , prior to the Closing, the Company has not conducted any business operations, has no assets or liabilities and is not a party to any contract or agreement of any kind or nature (other than the Organizational Documents of the Company).

        (c)   Upon Closing, the Class A Interests and the Class B Interests issued and sold pursuant to this Agreement (i) will constitute all of the issued and outstanding membership interests of the Company and (ii) will be duly authorized, validly issued and fully paid (to the extent required under the Company Operating Agreement). Except as set forth in the Company's Organizational Documents, there are no existing subscriptions, rights, warrants, calls, options, convertible or exchangeable securities, "phantom" equity rights, equity appreciation rights, equity-based performance units, commitments, contracts, agreements or undertakings of any character to which the Company is bound: (i) obligating the Company to issue, deliver or sell, or cause to be issued, delivered or sold, additional equity interests in, or any security convertible or exercisable for, or exchangeable into, any equity interest in the Company, or (ii) obligating the Company to issue, grant, extend or enter into any such option, warrant, call, right, security, commitment, contract, arrangement or undertaking. There are no outstanding contractual obligations of the Company to

5

repurchase, redeem or otherwise acquire any equity interests of the Company. There are no outstanding securities or other instruments convertible into or exchangeable for equity interests of the Company and no commitments to issue such securities or instruments. Except as set forth in the Company's Organizational Documents, there are no voting trusts, proxies or other agreements or understandings to which the Company is bound with respect to the voting of any equity interests or other securities of the Company.

        Section 3.5     Compliance with Law .    (a) MWE Liberty is (and to MWE Liberty's Knowledge has been) in compliance in all material respects with all Laws of any Governmental Authority applicable to the use, ownership and operation of the Assets; (b) MWE Liberty has not received written notice of any material violation of any such Law relating to the use, ownership and operation of the Assets; and (c) MWE Liberty is not in material default or violation of any order, writ, judgment, award, injunction or decree of any Governmental Authority applicable to the use, ownership or operation of the Assets.

        Section 3.6     No Default .    MWE Liberty is not in violation of its organizational, governing or charter documents. Except as set forth on Schedule 3.6 , MWE Liberty is not in default, and no event has occurred which, with notice or lapse of time or both, would give rise to a default, under, or give to others any rights of termination, amendment, acceleration or cancellation of or under, any agreement, credit facility, debt or other instrument (evidencing a debt or other obligation of MWE Liberty) to which MWE Liberty is a party, by which any of the Assets are bound or affected, except to the extent that such default, termination, amendment, acceleration or cancellation right (i) would not have or be reasonably expected to have, individually or in the aggregate, a Material Adverse Effect or (ii) results from obtaining the Miscellaneous Consents after the Closing pursuant to Section 6.5 .

        Section 3.7     Title to Properties and Assets .    Except as set forth on Schedule 3.7(a) , MWE Liberty and its Affiliates have good, valid and defensible title to all real property (other than real property and buildings held under lease by MWE Liberty) and personal property to be transferred pursuant to this Agreement and the constituent documents contemplated hereby, free and clear of all liens, encumbrances, security interests, equities, charges or claims or other restrictions whatsoever, except for Permitted Liens. With respect to any real property and buildings held under lease by MWE Liberty or its Affiliates, such real property and buildings are held under valid and subsisting and enforceable leases with such exceptions as do not materially interfere with the present or intended use of such properties by MWE Liberty and its Affiliates taken as a whole. Except as set forth on Schedule 3.7(b) , pursuant to the Assignment and Assumption, MWE Liberty and its Affiliates are validly transferring at Closing all of their ownership interests in the Assets to the Company, and the Assets so transferred (together with the Services (as defined in the Services Agreement) to be provided pursuant to the Services Agreement) constitute all rights and properties necessary in all material respects to operate the Business in a manner consistent with MWE Liberty's operation of the Business immediately prior to the Closing, other than the Miscellaneous Consents and contractual consents listed on Schedule 3.3 that may be obtained after the Closing pursuant to Section 6.5 .

        Section 3.8     Rights-of-Way .    Except as set forth on Schedule 3.8 , the Company, as of Closing, will have such easements or rights-of-way from each person (collectively, " Rights-of-Way ") as are necessary in all material respects to use, own and operate the Assets in the manner the Assets were used, owned and operated by MWE Liberty immediately prior to the Closing. Except as set forth on Schedule 3.8 , MWE Liberty has fulfilled and performed all of its material obligations with respect to such Rights-of-Way and no event has occurred that allows, or after notice or lapse of time would allow, revocation or termination thereof or would result in any impairment of the rights of the holder of any such Rights-of-Way, except for such revocations, terminations and impairments that would not have a Material Adverse Effect and the Miscellaneous Consents that may be obtained after the Closing pursuant to !Section 6.5 .

6

        Section 3.9     Financial Statements .     Schedule 3.9 is an accurate copy of the trial balance (the " Trial Balance ") of MWE Liberty as of December 31, 2008 (the " Trial Balance Date ") which accurately reflects the assets and material liabilities of MWE Liberty as of such date subject to normal year-end adjustments. Except as set forth on Schedule 3.9 , since the Trial Balance Date, there has not been any change in financial condition, properties, assets, liabilities, business or results of operations of the Business, which, individually or in the aggregate, has had or is reasonably likely to have a Material Adverse Effect. Since the Trial Balance Date, the Company has not incurred any obligation or liability (whether accrued, absolute, contingent or otherwise) of the type required to be reflected on a consolidated balance sheet of the Company prepared in accordance with GAAP applied on a basis consistent with the Trial Balance except liabilities and obligations incurred in the ordinary course of business and consistent with the Initial Budget or Section 6.8 hereof.

        Section 3.10     Environmental Matters .    Except as set forth in Schedule 3.10 :

        (a)   MWE Liberty and the Assets and operations thereof, are and, during the relevant time periods specified in all applicable statutes of limitations, have been in compliance in all material respects with Environmental Laws;

        (b)   MWE Liberty possesses, and is in compliance in all material respects with, all Environmental Permits for MWE Liberty's operation of the Assets as presently conducted and such Permits are in full force and effect subject to obtaining the Miscellaneous Consents after the Closing pursuant to Section 6.5 ;

        (c)   MWE Liberty is not subject to any pending or, to MWE Liberty's Knowledge, threatened, Proceeding with respect to its operation of the Assets, nor has MWE Liberty received any written notice of violation, noncompliance, or enforcement with respect to its operation of the Assets that remains pending or any written notice that it is or is suspected of being a potentially responsible party under CERCLA or any similar law with respect to its operation of the Assets that remains pending, or any written notice of investigation, remediation or request for information pursuant to Environmental Law from any Governmental Authority with respect to operation of the Assets that would reasonably be expected to result in a material liability to MWE Liberty pursuant to Environmental Laws, which notice of investigation, remediation or request for information remains pending;

        (d)   Except for such matters that would not reasonably be expected to give rise to any material liability, costs or remedial or corrective action obligations under Environmental Laws, (i) there has been no Release or, to MWE Liberty's Knowledge, threatened Release of Hazardous Substances by MWE Liberty or, to MWE Liberty's Knowledge, any third party; and (ii) no Hazardous Substances are present in, on, at, under or from any of the Assets, or otherwise in connection with the operation of the Assets by MWE Liberty;

        (e)   In connection with the operation of the Assets, MWE Liberty has not assumed or retained by written contract, or to MWE Liberty's Knowledge, by operation of law, any material liabilities (including STRICT LIABILITY) under any Environmental Laws for any Hazardous Substances; and

        (f)    MWE Liberty has made available to NGPMR and the Company complete and correct copies of all environmental assessment and audit reports and studies in its possession addressing potentially material environmental liabilities or obligations relating to MWE Liberty or its operation of the Assets.

        Notwithstanding any other provisions of this Agreement to the contrary, this Section 3.10 contains the sole and exclusive representations and warranties of MWE Liberty on environmental matters, including Environmental Laws, Environmental Claims, Environmental Responses, Environmental Permits and Hazardous Substances.

7

        Section 3.11     Material Contracts .    Each Material Contract is valid, binding and enforceable in accordance with its terms, and is in full force and effect. MWE Liberty has provided to NGPMR a true and complete copy of each Material Contract. MWE Liberty has not received any written notice of default under any Material Contract in the 12-month period prior to the date of this Agreement. Except as set forth on Schedule 3.11 , there are no (a) uncured defaults of MWE Liberty under any Material Contract that would give the counterparty thereto the right to terminate such Material Contract and (b) to MWE Liberty's Knowledge, defaults by any of the counterparties to such Material Contracts.

        Section 3.12     Legal Proceedings .    There are no Proceedings pending or, to the MWE Liberty's Knowledge, threatened, against MWE Liberty, the Company or the Assets. To MWE Liberty's Knowledge, there are no events or circumstances that have occurred which would reasonably be expected to result in Proceedings against MWE Liberty, the Company or the Assets.

        Section 3.13     Permits .    MWE Liberty has, and upon Closing, MWE Liberty will transfer to the Company and the Company will have (or have the benefit of pursuant to Section 6.5 ), all permits, approvals, consents, licenses, franchises, exemptions and other governmental authorizations, consents and approvals (collectively, " Permits ") necessary to use, own and operate the Assets as presently used, owned and operated, except for any such Permits the failure to have (or have the benefit of) would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. MWE Liberty has not received any written notification that it is in violation of any material Permits. MWE Liberty is in material compliance with all Permits.

        Section 3.14     Taxes .    All Tax Returns required to be filed with respect to MWE Liberty and the Assets have been filed and all such Tax Returns are complete and correct in all material respects; all Taxes due relating to MWE Liberty and the Assets have been paid in full (whether or not shown to be due on such Tax Returns). MWE Liberty has not received any written notice of deficiency or assessment from any taxing authority with respect to liabilities for Taxes of MWE Liberty or associated with the ownership or operation of the Assets, which have not been fully paid or finally settled, unless being contested in good faith through appropriate proceedings and for which adequate reserves have been established in the Trial Balance. All Taxes required to be withheld, collected or deposited by or with respect to MWE Liberty or associated with the ownership or operation of the Assets have been timely withheld, collected or deposited as the case may be, and to the extent required, have been paid to the relevant taxing authority. There are no outstanding agreements or waivers extending the applicable statutory periods of limitation for Taxes of MWE Liberty or that are associated with the ownership or operation of the Assets for any period. MWE Liberty, which was formed on March 26, 2008, is treated as a partnership or a disregarded entity for U.S. federal income Tax purposes and no election has been made to treat MWE Liberty as an association taxable as a corporation.

        Section 3.15     Employees .    

        (a)   Except as set forth on Schedule 3.15(a) , (i) neither MWE Liberty nor the Company has or previously had any employees and (ii) no Affiliate of MWE Liberty or the Company is a party to a collective bargaining agreement with its employees.

        (b)   Except as set forth on Schedule 3.15(b) , neither MWE Liberty nor the Company sponsors, maintains, has liability under or has an obligation to contribute to any "employee benefit plans" (within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (" ERISA "), including, without limitation, multiemployer plans within the meaning of Section 3(37) of ERISA), or any stock purchase, stock option, severance, employment, change-in-control, fringe benefit, collective bargaining, bonus, incentive, deferred compensation, employee loan or any other employee benefit plans, agreements, programs, policies or other arrangements, whether or not subject to ERISA (all such plans, agreements, programs, policies and

8

arrangements, collectively, the " Benefit Plans "). Neither MWE Liberty nor the Company, nor any of their ERISA Affiliates, have any liability under Section 412 of the Code or Title IV of ERISA.

        Section 3.16     Brokers' Fee .    Except for the fee payable to Morgan Stanley, which shall be paid by MWE, no broker, finder or similar intermediary has acted for or on behalf of, or is entitled to any broker, finder or similar fee or other commission from MWE Liberty, the Company or any of their Affiliates in connection with this Agreement or the transactions contemplated hereby.

        Section 3.17     Insurance .    MWE Liberty has provided or made available to NGPMR and the Company a true and complete list of all liability, property, workers' compensation and other insurance policies currently in effect that insure or relate to the Assets.

        Section 3.18     Intellectual Property .    Except as set forth on Schedule 3.18 , (a) MWE Liberty owns or has the right to use, and upon Closing and subject to the Miscellaneous Consents to be obtained after the Closing pursuant to Section 6.5 , the Company will own or have the right to use pursuant to license, sublicense, agreement (including the Services Agreement) or otherwise all items of Intellectual Property used in the operation of the Business as presently conducted, except for such Intellectual Property the failure of which to own or have the right to use, would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, (b) no third party has asserted in writing delivered to MWE Liberty a claim that MWE Liberty is infringing on the Intellectual Property of such third party and (c) to MWE Liberty's Knowledge, no third party is infringing on the Intellectual Property owned by MWE Liberty.

        Section 3.19     Affiliate Transactions .     Except as set forth on Schedule 3.19 , there are no existing agreements or transactions relating to the provision of material services (or otherwise providing for the payment of material amounts) between MWE Liberty, on the one hand, and any of its officers, managers, directors, employees, or any of their respective Affiliates, on the other hand. Except for any ownership interest in MWE, no officer, director, manager or employee of MWE Liberty has any direct or indirect material ownership interest in any Person with which MWE Liberty has any material business relationship.

ARTICLE 4
REPRESENTATIONS AND WARRANTIES OF NGPMR

        NGPMR hereby makes the following representations and warranties to the Company:

        Section 4.1     Organization .    NGPMR is a limited liability company duly formed, validly existing and in good standing under the laws of the State of Delaware and has all requisite limited liability company power and authority to own, lease and operate its properties and to carry on its business.

9

        Section 4.2     Authority; Enforceability .    

        (a)   NGPMR has the requisite limited liability company power and authority to execute and deliver the Transaction Documents to which it is a party, and to consummate the Transactions. The execution and delivery by NGPMR of the Transaction Documents to which it is a party, and the consummation by NGPMR of the Transactions, have been duly and validly authorized by NGPMR and no other limited liability company proceedings on the part of NGPMR is necessary to authorize the Transaction Documents or to consummate the Transactions.

        (b)   Each of the Transaction Documents to which NGPMR is a party has been (or will be, in the case of Transaction Documents to be delivered at Closing) duly executed and delivered by NGPMR and, assuming the due authorization, execution and delivery by the other parties thereto, each Transaction Document to which NGPMR is a party constitutes (or will constitute, in the case of Transaction Documents to be delivered at Closing) the valid and binding agreement of NGPMR, and is enforceable against NGPMR in accordance with its terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors' rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law).

        Section 4.3     No Violation; Consents and Approvals .    

        (a)   The execution, delivery and performance of the Transaction Documents by NGPMR and the consummation by NGPMR of the Transactions do not and will not: (i) result in any breach of any provision of the Organizational Documents, as amended, of NGPMR; (ii) constitute a default (or an event that with notice or lapse of time or both would give rise to a default) under, or give rise to any right of termination, cancellation, amendment or acceleration (with or without notice, lapse of time or both) under any of the terms, conditions or provisions of any contract, note, bond, mortgage, indenture, license, agreement or other instrument or obligation to which NGPMR is a party or by which any of its assets is bound, except to the extent that such default, termination, amendment, acceleration or cancellation right would not have or be reasonably expected to have, individually or in the aggregate, a Material Adverse Effect; or (iii) result in a violation of any law, statute, rule, regulation, order, judgment, injunction, decree or other restriction of any Governmental Authority to which NGPMR is subject (including federal and state securities laws and regulations) or by which any of its assets is bound.

        (b)   Other than the filings with respect to the HSR Act set forth in Section 6.1 , no declaration, filing or registration with, or notice to, or authorization, consent or approval of, any Governmental Authority is necessary for the consummation by NGPMR of the Transactions contemplated by the Transaction Documents, other than such declarations, filings, registrations, notices, authorization, consents or approvals that have been obtained or made prior to the Closing.

        Section 4.4     Brokers' Fee .    No broker, finder or similar intermediary has acted for or on behalf of, or is entitled to any broker, finder or similar fee or other commission from NGPMR or any of its Affiliates, in connection with this Agreement or the transactions contemplated hereby.

ARTICLE 5
INDEMNIFICATION

        Section 5.1     Survival .    

        (a)   The representations and warranties of MWE Liberty contained in Article 3 shall survive the Closing until the date that is ** after the date of the Closing, with the exception that the representations and warranties in (i) ** shall survive the Closing until ** after the ** and (ii) ** shall survive **. The representations and warranties of NGPMR contained in ** shall survive **,

10

with the exception