Exhibit 10.39

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 (**).

SECOND

AMENDED
AND RESTATED LIMITED LIABILITY COMPANY AGREEMENT

of

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

Dated
as of November 1, 2009

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TABLE OF CONTENTS

PageARTICLE 1 DEFINED TERMS

1Section 1.1

Definitions

1ARTICLE 2 FORMATION AND TERM

13Section 2.1

Formation

13Section 2.2

Name

13Section 2.3

Term

13Section 2.4

Registered Agent and Office

13Section 2.5

Principal Place of Business

13Section 2.6

Qualification in Other Jurisdictions

14ARTICLE 3 PURPOSE AND POWERS OF THE COMPANY

14Section 3.1

Purpose

14Section 3.2

Powers of the Company

14Section 3.3

Projects, Restricted Projects, Exempted Projects and Out of Scope Projects

14ARTICLE 4 CAPITAL CONTRIBUTIONS, MEMBER INTERESTS, CAPITAL ACCOUNTS AND FUTURE CAPITAL REQUIREMENTS

16Section 4.1

Capital Contributions

16Section 4.2

Capital Contribution Defaults

20Section 4.3

Member's Interest

20Section 4.4

Status of Capital Contributions

20Section 4.5

Capital Accounts

21Section 4.6

Capital Accounts Generally

21Section 4.7

Preferred Return

21Section 4.8

Investment Accounts

21Section 4.9

Equalization Target Date

22ARTICLE 5 MEMBERS, MEETINGS AND AMENDMENTS

23Section 5.1

Powers of Members

23Section 5.2

No Resignation or Expulsion

23Section 5.3

Additional Members

23Section 5.4

Confidentiality Obligations of Members

24Section 5.5

Initial Budget

25Section 5.6

Incentive Interests to MWE Liberty Upon Transfer of NGPMR's Interest

25Section 5.7

Preemptive Rights

25Section 5.8

Registration Rights

26ARTICLE 6 MANAGEMENT

26Section 6.1

Management Under Direction of the Board

26Section 6.2

Number, Tenure and Qualifications

27Section 6.3

Votes Per Manager; Quorum; Required Vote for Board Action; Meetings of the Board

28Section 6.4

Power to Bind Company

29Section 6.5

Liability for Certain Acts

29Section 6.6

Manager Has No Exclusive Duty to Company

30Section 6.7

Resignation and Withdrawal

30Section 6.8

Removal

30Section 6.9

Vacancies

30Section 6.10

Delegation of Authority; Officers

30


i

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PageSection 6.11

Designation of Operator

30Section 6.12

Approval of Members

32Section 6.13

Reliance by Third Parties

34Section 6.14

Fees and Expenses of the Managers

34Section 6.15

Budgets

34ARTICLE 7 ASSIGNABILITY OF MEMBER INTERESTS

36Section 7.1

Prohibition on Assignment During Project Period

36Section 7.2

Transfers After the Project Period

36Section 7.3

Recognition of Assignment by Company or Other Members

39Section 7.4

Effective Date of Assignment

39Section 7.5

Limitations on Transfer

39Section 7.6

Transferee Not a Substitute Member

40ARTICLE 8 DISTRIBUTIONS TO MEMBERS

40Section 8.1

Available Cash

40Section 8.2

Incentive Interest Percentage Distributions

41Section 8.3

Withholding

41Section 8.4

Limitations on Distribution

41Section 8.5

Tax Distributions

41ARTICLE 9 ALLOCATIONS

42Section 9.1

Profits and Losses

42Section 9.2

Special Allocations

42Section 9.3

Curative Allocations

43Section 9.4

Income Tax Allocations

44Section 9.5

Allocation and Other Rules

44ARTICLE 10 BOOKS AND RECORDS

45Section 10.1

Inspection Rights Pursuant to Law

45Section 10.2

Books and Records

45Section 10.3

Financial Statements and Reports

45Section 10.4

Accounting Method

46Section 10.5

Bank Accounts; Investments

46ARTICLE 11 TAX MATTERS

46Section 11.1

Taxation of Company

46Section 11.2

Tax Returns

46Section 11.3

Member Tax Return Information

46Section 11.4

Tax Matters Representative

46Section 11.5

Right to Make Section 754 Election

47Section 11.6

Tax Elections

47Section 11.7

Tax Reimbursement

47ARTICLE 12 LIABILITY, EXCULPATION AND INDEMNIFICATION

47Section 12.1

Liability

47Section 12.2

Exculpation

48Section 12.3

Indemnification

48Section 12.4

Expenses

48Section 12.5

Insurance

49Section 12.6

Certain Liabilities

49Section 12.7

Acts Performed Outside the Scope of the Company

49Section 12.8

Liability of Members to Company or Other Members

49


ii

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PageSection 12.9

Attorneys' Fees

49Section 12.10

Subordination of Other Rights to Indemnity

49Section 12.11

Survival of Indemnity Provisions

49ARTICLE 13 DISSOLUTION, LIQUIDATION AND TERMINATION

50Section 13.1

No Dissolution

50Section 13.2

Events Causing Dissolution

50Section 13.3

Notice of Dissolution

50Section 13.4

Liquidation

50Section 13.5

Termination

51Section 13.6

Claims of the Members or Third Parties

51Section 13.7

Distributions In-Kind

51ARTICLE 14 REPRESENTATIONS, WARRANTIES AND COVENANTS

52Section 14.1

Representations, Warranties and Covenants

52ARTICLE 15 MISCELLANEOUS

53Section 15.1

Notices

53Section 15.2

Failure to Pursue Remedies

53Section 15.3

Cumulative Remedies

53Section 15.4

Binding Effect

53Section 15.5

Interpretation

54Section 15.6

Severability

54Section 15.7

Counterparts

54Section 15.8

Integration

54Section 15.9

Amendment or Restatement

54Section 15.10

Governing Law

54Section 15.11

Dealings in Good Faith

54Section 15.12

Partition of the Property

55Section 15.13

Third Party Beneficiaries

55Section 15.14

Tax Disclosure Authorization

55Section 15.15

Waivers and Consents

55Section 15.16

Deadlocks; Negotiations

55Section 15.17

Dispute Resolution

56Section 15.18

Transaction Expenses

58




EXHIBITS:Exhibit A

Area of Mutual InterestExhibit B

Members and Capital ContributionsExhibit C

Base ProjectExhibit D

Initial BudgetExhibit E

Illustrative Example Calculation of Incentive InterestsExhibit F

[Reserved]Exhibit G

Capital Expenditures for AgreementsExhibit H

Pre-Approved Affiliated TransactionsExhibit I

[Reserved]Exhibit J

[Reserved]Exhibit K

[Reserved]


iii

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SECOND

AMENDED
AND RESTATED LIMITED LIABILITY COMPANY AGREEMENT

OF

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

THIS
SECOND AMENDED AND RESTATED LIMITED LIABILITY COMPANY AGREEMENT of MarkWest Liberty Midstream & Resources, L.L.C., a Delaware limited liability company (the
"Company"), is executed and agreed to as of November 1, 2009, 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 such other Persons who may become Members of the Company from time to time pursuant hereto.

WHEREAS,
MWE Liberty, as the then sole member of the Company, entered into that certain Limited Liability Company Agreement (the "Original
Agreement") of the Company, dated as of January 20, 2009;

WHEREAS,
pursuant to Section 11 of the Original Agreement, the Original Agreement was amended and restated in its entirety as set forth in that certain Amended and Restated
Limited Liability Company Agreement (the "First Amended Agreement") of the Company, dated as of February 27, 2009, and in connection therewith
MWE Liberty and NGPMR became the sole Members of the Company;

WHEREAS,
contemporaneously with the execution of the First Amended Agreement and in order to effect the contribution of the cash consideration comprising NGPMR's initial Capital
Contribution and the assets comprising MWE Liberty's initial Capital Contribution, the Company, MWE Liberty and NGPMR entered into that certain Contribution Agreement, dated January 22, 2009
(the "Contribution Agreement"), pursuant to which MWE Liberty agreed to contribute, convey, assign and transfer to the Company all of MWE Liberty's
right, title and interest in and to the assets referenced thereunder;

WHEREAS,
contemporaneously with the execution of the First Amended Agreement and in order to provide for the provision of certain services to the Company, the Company, MWE Liberty and
MarkWest Hydrocarbon, Inc., a Delaware corporation ("MWE Hydrocarbon") entered into that certain Services Agreement, dated February 27,
2009, (the "Services Agreement");

WHEREAS,
pursuant to Section 15.9 of the First Amended Agreement, the Company and the Members desire to amend and restate the First Amended Agreement in its entirety to, among
other things, revise the amount and timing of the additional Capital Contributions that certain of the Members have agreed to make to the Company;

NOW
THEREFORE, in consideration of the foregoing and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the First Amended Agreement is
hereby amended and restated in its entirety to read as follows:

ARTICLE 1  DEFINED TERMS

Section 1.1Definitions.

Unless
the context otherwise requires, the terms defined in this Article I shall, for the purposes of this Agreement, have the meanings herein specified.

"AAA" shall have the meaning set forth in Section 6.15(e).

"Accountants" shall have the meaning set forth in Section 4.1(a)(iii).

"Act" means the Delaware Limited Liability Company Act, 6 Del. C. §§ 18-101 et seq., as it may
be amended from time to time, and any successor statute thereto.

---



"Additional Member" shall have the meaning set forth in Section 5.3(a).

"Additional Projects" shall have the meaning set forth in Section 3.3(a).

"Adjusted Capital Account" means the Capital Account maintained for each Member (a) increased by any amounts the Member is
obligated to contribute or restore to the Company pursuant to the penultimate sentences of Treasury Regulations Sections 1.704-2(g)(1) and 1.704-2(i)(5), and
(b) decreased by any amounts described in Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), (5), or (6) with respect to such Member.

"Adjusted Capital Account Deficit" means a deficit balance in the Adjusted Capital Account of a Member.

"Affiliate" means with respect to a Person, any other Person that, directly or indirectly, Controls, is Controlled by, or is under Common
Control with, the specified Person.

"Affiliate Contract" means any contract between the Company or any Subsidiary of the Company, on the one hand, and a Member or an
Affiliate of a Member, on the other hand.

"Affiliated Member Group" means (a) the MWE Liberty Group, (b) the NGPMR Group and (c) any other Member and
transferee of Interests directly or indirectly (in the chain of title) from such Member that is an Affiliate of such transferee Member; provided, however, that once a Person is
designated as a member of any Affiliated Member Group, such Person shall, as long as it owns any Interests, at all times be a member of such Affiliated Member Group and not a member of any other
Affiliated Member Group, and provided, further, that for purposes of this clause (c) of this definition, an Affiliate shall not include a member of the MWE Liberty Group or the NGPMR Group.

"Agreement" means this Second Amended and Restated Limited Liability Company Agreement, as amended, modified, supplemented or restated
from time to time.

"Annual Financial Statements" shall have the meaning set forth in Section 10.3(a).

"Approved Budget" shall have the meaning set forth in Section 6.15(b).

"Arbitration Panel" shall have the meaning set forth in Section 6.15(e).

"Area of Mutual Interest" means the area**identified **as Exhibit A.

"Assumed Tax Liability" shall have the meaning set forth in Section 8.5(a).

"Available Cash" means, with respect to any period prior to the dissolution of the Company, all cash and cash equivalents of the Company
on hand at the end of such period less the amount of any cash reserves established by the Operator to provide for the proper conduct of the business of the Company, including reserves for: future
capital expenditures; current, future or contingent liabilities; anticipated future credit needs of the Company; and debt service and repayments; provided that such reserves shall not equal less than **as authorized in the Approved Budget nor more than**in the Approved Budget, without the approval of
the Board and Requisite Member Approval.

"Base Project" shall have the meaning set forth in Section 3.3(a).

"Board" shall have the meaning set forth in Section 6.1.

"Budget Rejection Notice" shall have the meaning set forth in Section 6.15(b).

"Business Day" means any day that is not a Saturday, Sunday or other day on which commercial banks are required or authorized by law to be
closed in the State of Texas or the State of Colorado.

"Capital Account" means, with respect to any Member, the capital account maintained for such Member in accordance with the provisions of
Section 4.5.

2

---



"Capital Call" means a call or request for additional capital in writing (which may include electronic mail) by or on behalf of the
Company, specifying the amount of capital requested to be contributed by each Member receiving such notice in accordance with the terms of this Agreement.

"Capital Contribution" means, with respect to any Member, the aggregate amount of cash and the initial Gross Asset Value of any property
other than cash contributed to the Company pursuant to Article 4 hereof by such Member. Any reference in this Agreement to a Capital Contribution of a Member shall include a Capital
Contribution contributed by its predecessors in interest.

"Cash Capital Contribution" means, with respect to any Member, the aggregate amount of cash contributed to the Company by such Member
disregarding (A) any Investment Balance credit pursuant to Section 4.1(b)(iv) and (B) any accrued Preference Amount.

"Certificate" means the Certificate of Formation of the Company filed on behalf of the Company with the office of the Secretary of State
of the State of Delaware pursuant to the Act on January 20, 2009, and any and all amendments thereto and restatements thereof.

"Claims" shall have the meaning set forth in Section 6.5.

"Class A Interest" means an Interest in the Company which is classified on Exhibit B as a Class A Interest and which
has the rights, powers and privileges enjoyed by a Member holding a Class A Percentage Interest (under the Act, the Certificate, this Agreement or otherwise) in its capacity as a Member, and
all obligations, duties and liabilities imposed on such a Member (under the Act, the Certificate, this Agreement or otherwise) in its capacity as a Member.

"Class A Manager" shall have the meaning set forth in Section 6.2.

"Class A Member" means a Member who is designated on Exhibit B as a Class A Member, in its capacity as a holder of a
Class A Percentage Interest.

"Class A Percentage Interest" means, with respect to a Class A Member, the quotient (expressed as a percentage) obtained by
dividing such Class A Member's Investment Balance by the aggregate Investment Balances of all Class A Members.

"Class B Interest" means an Interest in the Company which is classified on Exhibit B as a Class B Interest and which
has the rights, powers and privileges enjoyed by a Member holding a Class B Percentage Interest (under the Act, the Certificate, this Agreement or otherwise) in its capacity as a Member, and
all obligations, duties and liabilities imposed on such a Member (under the Act, the Certificate, this Agreement or otherwise) in its capacity as a Member.

"Class B Manager" shall have the meaning set forth in Section 6.2.

"Class B Member" means a Member who is designated on Exhibit B as a Class B Member, in its capacity as a holder of a
Class B Percentage Interest.

"Class B Percentage Interest" means, with respect to a Class B Member, the quotient (expressed as a percentage) obtained by
dividing such Class B Member's Investment Balance by the aggregate Investment Balances of all Class B Members.

"Class B Seller" shall have the meaning set forth in Section 7.2(b).

"Code" means the Internal Revenue Code of 1986, as amended from time to time, or any corresponding federal tax statute enacted after the
date of this Agreement.

"Company" shall have the meaning set forth in the preamble.

"Company Minimum Gain" shall have the meaning assigned to the term "partnership minimum gain" in Treasury Regulations
Sections 1.704-2(b)(2) and 1.704-2(d).

3

---



"Company Nonrecourse Liability" shall have the meaning assigned to the term "nonrecourse liability" in Treasury Regulations
Section 1.704-2(b)(3)

**shall have the meaning set forth in Section 4.9(b).

**shall have the meaning set forth in Section 4.9(c).

"Confidential Information" shall mean all information provided or made available by or on behalf of the Company or its Representatives to
a Member or its Representatives, including all information, data, reports, interpretations, contract terms and conditions, forecasts and records containing or otherwise reflecting information
concerning the Company or its Affiliates, potential counterparties or customers or their Affiliates, potential projects, business plans or proposals, market or economic data, identities of actual or
potential counterparties or customers, designs, concepts, trade secrets and other business, operational or technical information (irrespective of the form of communication of such information) and
together with analyses, compilations, studies or other documents, whether prepared by or on behalf of a Member or its Representatives, which contain or otherwise reflect such information (irrespective
of the form of communication of such information). "Confidential Information" also includes information of third parties, including such information as may be subject to any Third Party
Confidentiality Agreements. Notwithstanding the foregoing, Confidential Information shall not include the following: (a) information which at the time of disclosure by or on behalf of the
Company is publicly available or which later becomes publicly available through no act or omission of the disclosing Member or its Representatives; (b) information which a Member can
demonstrate was in its possession on a non-confidential basis prior to disclosure by or on behalf of the Company hereunder; (c) information received by a Member from a third party
who is not prohibited from transmitting the information by a contractual, legal or fiduciary obligation; or (d) information which a Member can demonstrate was independently developed by it or
for it and which was not derived or obtained, in whole or in part, from Confidential Information or from the Company or its Representatives hereunder.

"Contributing Class A Member" shall mean a Class A Member who makes a Quarterly Budgeted Funding Election in accordance with
Sections 4.1(c) or (d).

"Contributing Class B Member" shall mean a Class B Member who makes a Quarterly Budgeted Funding Election in accordance with
Section 4.1(d).

"Contribution Agreement" shall have the meaning set forth in the recitals.

"Control," including the correlative terms "Controlling," "Controlled by" and "Under Common Control with" means possession, directly or
indirectly (through one or more intermediaries), of the power to direct or cause the direction of the management or policies (whether through ownership of securities or any partnership or other
ownership interest, by contract or otherwise) of a Person. For the purposes of this definition, ownership of more than 50% of the voting interests of any entity shall be conclusive evidence that
Control exists.

"Covered Person" means, in each case, whether or not a Person continues to have the applicable status referred to in the following list: a
Member; a Manager; the Operator; any Affiliate of a Member or a Manager or of the Operator; any officers of the Company, whether or not such officers are employees of the Company; any officers,
directors, members, managers, stockholders, partners, employees, representatives or agents of any Manager or Member or of the Operator, or of any of their respective Affiliates; any employee or agent
of the Company or its Affiliates; and any Tax Matters Member of the Company.

"CP Index" means the United States Department of Labor, Bureau of Labor Statistics Consumer Price IndexAll Urban Consumers,
U.S. City Average, Not Seasonally Adjusted, or, if such index is

4

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discontinued,
any successor or substitute index, which, in the Board's reasonable opinion, is most nearly equivalent to such index.

"Debt" for any Person means, without duplication: (a) indebtedness of such Person for borrowed money, including obligations under
letters of credit and agreements relating to the issuance of letters of credit or acceptance financing; (b) obligations of such Person evidenced by bonds, debentures, notes, or other similar
instruments; (c) obligations of such Person to pay the deferred purchase price of property or services (including, without limitation, obligations that are non-recourse to the
credit of such Person but are secured by the assets of such Person, but excluding trade accounts payable); (d) obligations of such Person under capital leases; and (e) obligations of
such Person under guarantees in respect of indebtedness or obligations of others of the kinds referred to in clauses (a) through (d) above; provided that "Debt" shall not include the
incurrence of trade debt in the ordinary course of business.

"Default Rate" means a per annum rate of interest equal to the lower of**and the maximum
rate of interest then permitted by law.

"Defaulting Member" shall have the meaning set forth in Section 4.2.

"Depreciation" means, for each Fiscal Year or other period, an amount equal to the depreciation, amortization or other cost recovery
deduction allowable for federal income tax purposes with respect to an asset for such Fiscal Year or other period and in a manner consistent with the methodologies employed by MWE or otherwise
determined by the Board; provided, however, that if the Gross Asset Value of an asset differs from its adjusted basis for federal income tax purposes at the beginning of such Fiscal Year or other
period, Depreciation for such Fiscal Year or other period shall equal to the amount of book basis recovered for such Fiscal Year or other period under the rules prescribed by Treasury Regulation
Section 1.704-3(d)(2) and provided further, that if the federal income tax depreciation, amortization or other cost recovery deduction for such Fiscal Year or other period is zero,
Depreciation shall be determined with reference to such beginning Gross Asset Value using any reasonable method selected by the Board.

"Designated MWE Employees" has the meaning ascribed to such term in the Services Agreement.

"Dispute" has the meaning set forth in Section 15.17(a).

"Economic Risk of Loss" shall have the meaning assigned to that term in Treasury Regulation Section 1.752-2(a).

"Effective Time" means 12:01 a.m. on January 1, 2009.

"Election Period" shall have the meaning set forth in Section 5.7(b).

"Electing Member" shall have the meaning set forth in Section 5.7(b).

"Eligible Member" shall have the meaning set forth in Section 5.7(a).

"Enforcement Activities" shall have the meaning set forth in Section 6.3(a).

"Equalization Date" shall mean the first date after**on which the quotient (expressed as
a percentage) obtained by dividing the aggregate Investment Balances of all members of the MWE
Liberty Group by the aggregate Investment Balances of all members of the MWE Liberty Group plus all members of the NGPMR Group is equal to or greater than 51%.

"Equalization Target Date" shall have the meaning set forth in Section 4.9(a).

"Exchange Act" means the Securities Exchange Act of 1934, and the rules and regulations promulgated thereunder, as amended and any
successor statutes thereto.

"Exempted Project" shall have the meaning set forth in Section 3.3(b).

5

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"Final Impasse" shall have the meaning set forth in Section 15.16(b).

"First Amended Agreement" shall have the meaning set forth in recitals.

"First Notice" shall have the meaning set forth in Section 5.7(b).

"Fiscal Year" means (i) the period commencing at the Effective Time and ending on December 31, 2010 and (ii) any
subsequent 12 month period commencing on January 1 and ending on December 31.

"Fractionation and NGL Purchase Agreement" means that certain Fractionation and NGL Purchase Agreement, dated February 27, 2009, by
and between MWE Hydrocarbon and the Company, as amended, restated and supplemented from time to time.

"G&A Services" has the meaning ascribed to such term in the Services Agreement.

"GAAP" means generally accepted accounting principles in the United States.

**means that certain**by and between MarkWest Liberty Gas Gathering, L.L.C. and **, as amended, restated and
supplemented from time to time.

"Gross Asset Value" means, with respect to any asset, such asset's adjusted basis for federal income tax purposes, except as follows:



If
the Gross Asset Value of an asset has been determined or adjusted pursuant to paragraph (a) or paragraph (b) above, such Gross Asset Value shall thereafter be adjusted by the
Depreciation taken into account with respect to such asset for purposes of computing Profits and Losses.

"Impasse" shall have the meaning set forth in Section 15.16(a).

6

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"Impasse Notice" shall have the meaning set forth in Section 15.16(a).

"Incentive Interest Transaction" shall have the meaning set forth in Section 5.6.

"Indentures" has the meaning ascribed to such term in the Contribution Agreement.

"Indemnitee" shall have the meaning set forth in Section 12.7.

"Indemnitor" shall have the meaning set forth in Section 12.7.

"Initial Budget" shall have the meaning set forth in Section 5.5.

"Interest" means the interest of a Member in the Company, including both Class A Percentage Interests and Class B Percentage
Interests, including rights to distributions (liquidating or otherwise), allocations, notices and information, rights to approve of or consent to certain matters (if applicable) and all other rights,
benefits and privileges enjoyed by that Member (under the Act, the Certificate, this Agreement, or otherwise) in its capacity as a Member; and all obligations, duties and liabilities imposed on that
Member (under the Act, the Certificate, this Agreement, or otherwise) in its capacity as a Member.

"Investment Account" shall have the meaning set forth in Section 4.8.

"Investment Balance" shall have the meaning set forth in Section 4.8.

"Investment Threshold" shall have the meaning set forth in Section 4.1(c).

"IPO Issuer" means (a) the Company or (b) an Affiliate of the Company which will be a successor to the Company and the
issuer in a Qualified Public Offering.

"Lien" means, with respect to any asset, any mortgage, lien, pledge, charge, security interest or encumbrance of any kind in respect of
such asset.

"Liquidating Trustee" shall have the meaning set forth in Section 13.4(a).

"Manager" shall have the meaning set forth in Section 6.1.

"Member" means any Person (but not any Affiliate or entity in which such Person has an equity interest) executing this Agreement and any
Person admitted as an Additional Member or a Substitute Member pursuant to the provisions of this Agreement, in such Person's capacity as a Member of the Company, and "Members" means two or more of
such Persons, in their capacities as Members of the Company. Such terms do not include any Person or Persons who have ceased to be Members in the Company.

"Member Nonrecourse Debt" has the meaning assigned to the term "partner nonrecourse debt" in Treasury Regulation
Section 1.704-2(b)(4).

"Member Nonrecourse Debt Minimum Gain" shall have the meaning assigned to the term "partner nonrecourse debt minimum gain" in Treasury
Regulation Section 1.704-2(i)(2).

"Member Nonrecourse Deductions" shall have the meaning assigned to the term "partner nonrecourse deductions" in Treasury Regulation
Section 1.704-2(i)(1).

"Minimum Gain" shall have the meaning assigned to that term in Treasury Regulation Section 1.704-2(d).

"Minimum Price" shall have the meaning set forth in Section 7.2(b)(ii).

"Monthly Reports" shall have the meaning set forth in Section 10.3(c).

"MWE" means MarkWest Energy Partners, L.P., a Delaware limited partnership.

"MWE Hydrocarbon" shall have the meaning set forth in the recitals.

7

---



"MWE Liberty" shall have the meaning set forth in the preamble.

"MWE Liberty Group" means MWE Liberty and each transferee of Interests directly or indirectly (in the chain of title) from MWE Liberty
that is an Affiliate of MWE Liberty; provided, however, that once a Person is designated as a member of the MWE Liberty Group such Person shall, as long as it owns any Interests, at all times be a
member of the MWE Liberty Group and not a member of any other Affiliated Member Group; provided further, that for purposes of this definition, an Affiliate shall not include a member of any other
Affiliated Member Group.

"New Interests" shall have the meaning set forth in Section 5.7(a).

"NGPMR" shall have the meaning set forth in the preamble.

"NGPMR Covered Persons" has the meaning ascribed to such term in the Contribution Agreement.

"NGPMR Exit Transaction" means**involving the Company in which **in which the**prior to the**of the Company **or a**of the Company**. For the avoidance of doubt,
any**

"NGPMR Group" means NGPMR and each transferee of Interests directly or indirectly (in chain of title) from NGPMR that is an Affiliate of
NGPMR; provided, however, that once a Person is designated as a member of the NGPMR Group such Person shall, as long as it owns any Interests, at all times be a member of the NGPMR Group and not a
member of any other Affiliated Member Group, and, provided further, that for purposes of this definition, an Affiliate shall not include a member of any other Affiliated Member Group.

"NGPMR Portfolio Companies" shall have the meaning set forth in Section 3.3(c).

"NGPMR Representatives" shall mean the members, managers and employees of NGPMR or any Affiliate thereof, together with all other persons
serving as representatives of NGPMR, including those Persons who are serving as Managers at the request of NGPMR pursuant to this Agreement.

"Non-Contributing Class A Member" shall mean a Class A Member who does not elect to make a Quarterly Budgeted
Funding Election in accordance with Section 4.1(c).

"Non-Contributing Class B Member" shall mean a Class B Member who does not elect to make a Quarterly Budgeted
Funding Election in accordance with Section 4.1(d).

"Nonrecourse Deductions" shall have the meaning assigned to that term in Treasury Regulation Section 1.704-2(b).

"Operator" means the Person designated as the "Operator" of the Company in accordance with Section 6.11.

"Original Agreement" shall have the meaning set forth in the recitals.

"Out of Scope Project" means any project, activity, or business venture (a) outside the Area of Mutual Interest or (b) not
within the scope of the Primary Business of the Company (whether inside or outside the Area of Mutual Interest).

"Over-Allotment Amount" shall have the meaning set forth in Section 5.7(b).

"Overfunded Capital" means, as of any determination date (a) on or prior to**, the
difference (expressed as a dollar amount) between**, and (b) after**, the difference (expressed
as a dollar amount) between**.

"Partial NGPMR Exit Transaction" means**after which the **in the**after which the**

8

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"Percentage Interest" means:



"Permitted Liens" means (a) statutory liens for current taxes or assessments not yet due and delinquent or the validity of which is
being contested in good faith by appropriate proceedings and for which adequate reserves have been established; (b) mechanics', carriers', workers', repairers' and other similar liens arising
or incurred in the ordinary course of business; and (c) all applicable zoning ordinances and land use restrictions.

"Permitted Transfers" shall have the meaning set forth in Section 7.1.

"Personnel Services" has the meaning ascribed to such term in the Services Agreement.

"Person" means any natural person, corporation, limited partnership, general partnership, limited liability company, joint stock company,
joint venture, association, company, estate, trust, bank trust company, land trust, business trust, or other organization, whether or not a legal entity, custodian, trustee-executor, administrator,
nominee or entity in a representative capacity and any government or agency or political subdivision thereof.

"Preference Amount" means an amount calculated on the last day of each calendar quarter following the Effective Time and prior to the
Equalization Date by determining the difference between (a) the amount of Overfunded Capital as of the last day of such quarter, multiplied by the Preference Rate and (b) the amount of
all distributions made during such calendar quarter pursuant to Section 8.1(b)(i)(A). The Preference Amount for the prior calendar quarter shall be added to the Investment Balance as of the
first day of the following calendar quarter.

"Preference Rate" means a quarterly rate expressed as a percentage equal to**per annum,
divided by four.

"Primary Business" shall have the meaning set forth in Section 3.1(a).

"Profits" or "Losses" means, for each Fiscal Year, an amount equal to the Company's
taxable income or loss for such Fiscal Year, determined in accordance with Section 703(a) of the Code (but including in taxable income or loss, for this purpose, all items of income, gain, loss
or deduction

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required
to be stated separately pursuant to Section 703(a)(1) of the Code), with the following adjustments:



"Project Period" shall have the meaning set forth in Section 7.1.

"Projects" shall have the meaning set forth in Section 3.3(a).

"Property" means all of the assets and property now owned or hereafter acquired by the Company.

"Proposed Budget" shall have the meaning set forth in Section 6.15(a).

"Proposed Purchaser" shall have the meaning set forth in Section 5.7(a).

"Prudent Industry Practices" means, at a particular time, any of the practices, methods and acts which, **based upon the**, and the**, at such time, is **operation and maintenance of the Company assets and shall include, without limitation, the practices, methods and
acts engaged in or approved by**at such time with respect to the assets of the same or similar types as the Company assets. Prudent Industry Practices are not intended to be limited
to**to the exclusion of all others, but rather is**practices, methods and acts which **at a**as well as with the**. Prudent Industry
Practices are intended to entail the**, in the**, use from time to time.

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"Qualified Public Offering" means any underwritten initial public offering by the IPO Issuer of equity securities pursuant to an effective
registration statement under the Securities Act and for which aggregate cash proceeds to be received by the IPO Issuer from such offering (without deducting underwriting discounts, expenses and
commissions) are at least $50,000,000.

"Qualifying Third Party Offer" shall have the meaning set forth in Section 7.2(a)(ii).

"Quarterly Budgeted Funding Election" shall have the meaning set forth in Sections 4.1(c) and (d).

"Quarterly Financial Statements" shall have the meaning set forth in Section 10.3(b).

"Regulatory Allocations" shall have the meaning set forth in Section 9.3.

"Remaining Members" shall have the meaning set forth in Section 7.2(a).

"Representatives" means (a) with respect to the Company, any of: (i) the Company's Affiliates; and (ii) directors,
officers, managers, employees, members, partners, agents and authorized representatives (including attorneys, accountants, consultants, bankers, lenders and financial advisors) of the Company and the
Company's Affiliates and (b) with respect to a Member, any of: (i) such Member's Affiliates; (ii) directors, officers, managers, employees, members, stockholders, partners, agents
and authorized representatives (including attorneys, accountants, consultants, bankers, lenders and financial advisors) of the Member and the Member's Affiliates; and (iii) Persons who are (or
who are prospective) beneficial owners of equity interests in such Member.

"Requisite Member Approval" means the approval of each Affiliated Member Group holding Interests with (i) an aggregate Percentage
Interest equal to or exceeding**or (ii) an**.

"Restricted Project" has the meaning set forth in Section 3.3(b).

"ROFO Interest" shall have the meaning set forth in Section 7.2(a).

"ROFO Offer" shall have the meaning set forth in Section 7.2(a).

"Rules" shall have the meaning set forth in Section 6.15(e).

"Sale Proposal" shall have the meaning set forth in Section 7.2(b)(i).

"Securities Act" means the Securities Act of 1933, and the rules and regulations promulgated thereunder, as amended and any successor
statutes thereto.

"Services Agreement" shall have the meaning set forth in the recitals.

"Solicitation Notice" shall have the meaning set forth in Section 7.2(b)(ii).

"Solicitation Period" shall have the meaning set forth in Section 7.2(a)(ii).

"Solicitation Response" shall have the meaning set forth in Section 7.2(b)(ii).

"Subsidiary" means, with respect to any Person, (a) any corporation, of which a majority of the total voting power of shares of
stock entitled (without regard to the occurrence of any contingency) to vote generally in the election of directors thereof is at the time owned or controlled, directly or indirectly, by that Person
or one or more of the other Subsidiaries of that Person or a combination thereof or (b) any limited liability company, partnership, association or other business entity, of which a majority of
the partnership or other similar ownership interests thereof is at the time owned or controlled, directly or indirectly, by that Person or one or more Subsidiaries of that Person or a combination
thereof. For purposes of this definition, a Person or Persons will be deemed to have a majority ownership interest in a limited liability company, partnership, association or other business entity if
such Person or Persons will be allocated a majority of limited liability company, partnership,

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association
or other business entity gains or losses, or is or controls the managing member or general partner of such limited liability company, partnership, association or other business entity.

"Substitute Member" means a Person who is admitted to the Company as a Member pursuant to Article 7, and then designated as a
"Member" on an amended Exhibit B to this Agreement.

"Tag-Along Members" shall have the meaning set forth in Section 7.2(b).

"Tag-Along Notice" shall have the meaning set forth in Section 7.2(b)(i).

"Tag-Along Notice Period" shall have the meaning set forth in Section 7.2(b)(i).

"Tag-Along Rights" shall have the meaning set forth in Section 7.2(b).

"Tax Distribution Date" shall have the meaning set forth in Section 8.5(a).

"Tax Matters Member" shall have the meaning set forth in Section 11.4(a).

"Third Party Confidentiality Agreements" means that certain**among MWE Liberty, **, the**, that certain**between**and MWE Liberty, that certain**between**and MWE
Liberty**and that certain**between**and MWE
Liberty**or any other third party agreement entered into by or on behalf of the Company and delivered to a Member.

"Third Party Offer" shall have the meaning set forth in Section 7.2(a)(ii).

"** Payout" shall mean the dollar threshold, if any, at which the NGPMR Group has received a cumulative cash amount in respect of the
NGPMR Group's Interests (whether as distributions from the Company or as cash payment in an Incentive Interest Transaction) equal to the**as of the
date of such cash payment**where**is equal to the**determined as of the date of such cash payment or distribution.

"** Payout Threshold" shall mean the receipt by the NGPMR Group of a cumulative cash amount in respect of the NGPMR Group's Interests
(whether as distributions from the Company or as cash payment in an Incentive Interest Transaction) equal to the**where **is equal to the**determined as of the date of such distribution or cash payment.

"** Percentage" shall mean**.

**

"Transaction Documents" shall have the meaning set forth in Section 5.1(b).

"Transfer" means any direct or indirect transfer, assignment, sale, conveyance, license, lease, or partition of any Interest, and includes
any "involuntary transfer" such as a sale of any part of the Interest therein in connection with any bankruptcy or similar insolvency proceedings, or any other disposition of any Interest. A Transfer
shall not include any pledge, hypothecation or encumbrance of any Interest.

"Transferring Member" shall have the meaning set forth in Section 7.2(a).

"Treasury Regulations" means the income tax regulations, including temporary regulations, promulgated under the Code, as such regulations
may be amended from time to time (including corresponding provisions of succeeding regulations).

"True-Up Contribution" shall have the meaning set forth in Section 4.9(a).

**
means that certain**by and between MWE Liberty and**as amended by Amendment
No. 1 to**by and between MWE Liberty and**.

"Unrelated Information" shall have the meaning set forth in Section 10.2.

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"Weighted Average Capital Contribution Factor" shall mean as of any date of calculation, a weighted average **the amounts determined for each date on which NGPMR has
made Capital Contributions (including without limitation the Capital Contributions funded on
the date hereof) calculated as**of the total**years from the date of each Capital Contribution until
the date of such calculation (with a partial year being expressed as a decimal determined by dividing the number of days which have passed since the most recent anniversary by 365). Solely for
purposes of determining Capital Contributions under this definition, (i)**shall be treated as a Capital Contribution made by the NGPMR Group as
of the date**, and (ii) any other amounts**shall be treated as Capital Contributions made by
the NGPMR Group as of the date**.

ARTICLE 2  FORMATION AND TERM

Section 2.1Formation.



Section 2.2Name.

The
business and affairs of the Company shall be conducted under the name "MarkWest Liberty Midstream & Resources, L.L.C." and such name shall be used at all times in connection
with the Company's business and affairs, except to the extent the Board agrees to the use by the Company of assumed names or other trade names or fictitious names. The Company's Managers or officers
or the Operator shall execute such assumed or fictitious name certificates as may be desirable or required by law to be filed in connection with the business and affairs of the Company and shall cause
such certificates to be filed in all appropriate public records.

Section 2.3Term.

The
term of the Company commenced upon the effectiveness of the Certificate and shall continue perpetually, unless the Company is dissolved in accordance with the provisions of this
Agreement.

Section 2.4    Registered
Agent and Office.

The
registered office of the Company required by the Act to be maintained in Delaware shall be the office of the initial registered agent named in the Certificate or such other office
(which need not be a place of business of the Company) as the Board may designate in the manner provided by law. The registered agent of the Company in Delaware shall be the initial registered agent
named in the Certificate or such other Person or Persons as the Board may designate in the manner provided by law.

Section 2.5    Principal
Place of Business.

The
principal place of business of the Company shall be 1515 Arapahoe Street, Tower 2, Suite 700, Denver, CO 80202. At any time, the Board may change the location of the Company's
principal place of business. The Company may have such other places of business as the Board or the Operator may designate.

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Section 2.6    Qualification
in Other Jurisdictions.

The
Managers, the officers of the Company or the Operator shall cause the Company to be qualified, formed or registered under assumed or fictitious name statutes or similar laws in any
jurisdiction in which the Company transacts business. The Managers, the officers of the Company or the Operator shall execute, deliver and file any certificates (and any amendments and/or restatements
thereof) necessary or appropriate for the Company to qualify and continue to do business in a jurisdiction in which the Company may wish to conduct business. At the request of the Board or the
Operator, each Member shall execute, acknowledge, swear to and deliver all certificates and other instruments conforming with this Agreement that are necessary or appropriate to qualify, continue and
terminate the Company as a foreign limited liability company in all such jurisdictions in which the Company may conduct business, provided that no Member shall be required to file any general consent
to service of process or to qualify as a foreign corporation, limited liability company, partnership or other entity in any jurisdiction in which it is not already so qualified.

ARTICLE 3  PURPOSE AND POWERS OF THE COMPANY

Section 3.1Purpose.



Section 3.2Powers of the Company.

The
Company shall have all powers and privileges granted by the Act, any other law, or by this Agreement, including incidental powers thereto, to the extent that such powers and
privileges are necessary, customary, convenient or incidental to the attainment of the Company's purpose.

Section 3.3Projects, Restricted Projects, Exempted Projects and Out of Scope Projects.



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Each
Member recognizes and affirms that in the event of breach by such Member of any of the provisions of this Section 3.3(b), money damages may be inadequate and the
non-breaching Members may have no adequate remedy at law. Accordingly, each Member agrees that the non-breaching Members shall have the right, in addition to any other rights
and remedies existing in their favor, to enforce their rights and each of the Members' obligations under this Section 3.3(b) not only by an action or actions for damages, but also by an action
or actions for specific performance, injunctive and/or other equitable relief in order to enforce or prevent any violations (whether anticipatory, continuing or future) of the provisions of this
Section 3.3(b).



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ARTICLE 4  CAPITAL CONTRIBUTIONS, MEMBER INTERESTS,  CAPITAL ACCOUNTS AND FUTURE CAPITAL REQUIREMENTS

Section 4.1Capital Contributions.



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Section 4.2Capital Contribution Defaults.

If
a Member fails to contribute any capital to the Company that is required to be so contributed pursuant to Section 4.1, such Member shall be considered in default (a
"Defaulting Member"), but shall remain fully obligated to contribute such capital to the Company. The Company shall be entitled to pursue all remedies
available at law or in equity against the Defaulting Member, including any one or more of the following:



Section 4.3Member's Interest.

A
Member's Interest shall for all purposes be personal property. Title to the Company's assets, whether real, personal or mixed and whether tangible or intangible, shall be deemed to be
owned by the Company as an entity, and no Member, Manager, Operator or officer of the Company shall have any ownership interest in such Company assets.

Section 4.4Status of Capital Contributions.



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Section 4.5Capital Accounts.



Section 4.6Capital Accounts Generally.



Section 4.7Preferred Return.

For
the avoidance of doubt, the Class A Interests shall accrue the Preference Amount until the Equalization Date, after which time the Preference Amount shall no longer accrue.

Section 4.8Investment Accounts.

The
Company shall maintain an investment account (an "Investment Account") for each Member, the balance of which (the
"Investment Balance") shall represent the sum of a Member's initial Capital Contribution, any additional Capital Contributions made by a Member pursuant
to Sections 4.1(b), 4.1(c), 4.1(d) and 4.9, and with respect to each Class A Member, (i) the Preference Amount and

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(ii) the
amount that is retained by the Company in accordance with Section 4.1(b)(iv) and which such Class A Member would have otherwise received if Available Cash were
distributed prior to December 31, 2010. The Investment Balance for each Class A Member shall be reduced by any actual distributions to such member of Available Cash pursuant to
Section 8.1(b)(i)(A) and Sections 13.4(a)(i)(A) and (B). For the avoidance of doubt, the Investment Balance of each Member as of the date hereof is set forth on Exhibit B. An
assignee of all or any portion of an Interest shall succeed to a portion of the assignor Member's Investment Account in proportion to the Interest acquired.

Section 4.9Equalization Target Date.



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ARTICLE 5  MEMBERS, MEETINGS AND AMENDMENTS

Section 5.1Powers of Members.



Section 5.2No Resignation or Expulsion.

A
Member may not take any action to resign, withdraw or retire as a Member voluntarily, and a Member may not be expelled or otherwise removed involuntarily as a Member, prior to the
dissolution and winding up of the Company, other than as a result of a Permitted Transfer of all of such Member's
Interests in accordance with Article 7 and each of the transferees of such Interests being admitted as a Substitute Member.

Section 5.3Additional Members.



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Section 5.4Confidentiality Obligations of Members.



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Section 5.5Initial Budget.

By
execution of this Agreement, the Members hereby approve and consent to the initial budget attached hereto as Exhibit D (the "Initial
Budget") and acknowledge and agree that such Initial Budget shall be deemed to be an Approved Budget for all purposes of this Agreement.

Section 5.6Incentive Interests to MWE Liberty Upon Transfer of NGPMR's Interest.

In
the event NGPMR receives cash from any NGPMR Exit Transaction or Partial NGPMR Exit Transaction (for the purposes of this section, such transaction an
"Incentive Interest Transaction") that would result in**Payout**, simultaneously with the consummation of any such transaction, NGPMR shall pay to MWE Liberty as a fee the following
amount**, to the extent applicable:



Exhibit E contains illustrative examples of the calculation and operation of amount**payable pursuant to
Section 5.6**based upon hypothetical Incentive Interest Transactions. This Section 5.6 shall be interpreted and applied in a manner
consistent with the examples set forth in Exhibit E. The obligations of NGPMR to make payment**to MWE Liberty pursuant to this
Section 5.6 shall survive the closing of any NGPMR Exit Transaction or Partial NGPMR Exit Transaction and any liquidation, dissolution or winding up of the Company until such payment to MWE
Liberty has been made.

Section 5.7Preemptive Rights.



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Section 5.8Registration Rights.

If
the Board with Requisite Member Approval determines to effect a Qualified Public Offering, each of the Members shall be granted customary registration rights, including piggyback
registration rights, with respect to such Qualified Public Offering.

ARTICLE 6  MANAGEMENT

Section 6.1Management Under Direction of the Board.

Except
as otherwise expressly provided in this Agreement or required under the Act, the business and affairs of the Company shall be managed by a board of managers (the
"Board" and each member of the Board, a "Manager"), and the Board shall have full and complete
authority, power, and discretion to manage and control the business, affairs, and properties of the Company, to make all decisions regarding those matters and to perform any and all other acts or
activities customary or incidental to the management of the Company's business. Without limiting the generality of the foregoing the approval of the Board shall be required for all matters not
delegated by the Board to the Operator, the officers of the Company or to other authorized persons in accordance with Section 6.10,

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including
approval of the following matters, which the Board shall not have the power to delegate to any Person, in each case except as otherwise approved in any Approved Budget:



Section 6.2Number, Tenure and Qualifications.



The
initial Managers of the Company shall be: John T. Raymond, Jeffrey Rawls and Patrick Wade, who are the Class A Managers, and John Mollenkopf, Randy Nickerson and Frank Semple,
who are the Class B Managers.



Any
Manager designated in accordance with this section shall be immediately removed from the Board at any time that the Affiliated Member Group that designated such Manager ceases to own
aggregate Percentage Interests that would permit such Affiliated Member Group to designate such Manager in accordance with the first sentence of this section. Notwithstanding the foregoing, so long as
the Class A Members have**, such Class A Members shall be entitled to appoint no less than one

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Manager
to the Board and the size of the Board shall be, if necessary, increased by one to enable the Class A Members to make such appointment. The Board shall be comprised of the total number
of Managers that all Affiliated Member Groups are entitled to so designate pursuant to the first sentence of this Section 6.2(b), plus any additional Manager whom the Class A Members are
entitled to designate pursuant to the immediately preceding sentence. At any time that any Affiliated Member Group acquires aggregate Percentage Interests sufficient to permit such Affiliated Member
Group to designate one or more additional Managers in accordance with the first sentence of this Section, then a new Manager position shall be created and such Affiliated Member Group shall be
entitled to fill such the vacancy in such position in accordance with Section 6.9.



Section 6.3Votes Per Manager; Quorum; Required Vote for Board Action; Meetings of the Board.



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Section 6.4Power to Bind Company.

Unless
authorized to do so by this Agreement or by the Board, no Member of the Company shall have any power or authority to bind the Company in any way, to pledge the Company's credit or
to render it liable pecuniarily for any purpose. However, a Person may act by a duly authorized attorney-in-fact executed in writing by the Board.

Section 6.5Liability for Certain Acts.

No
Manager or officer of the Company (solely in such individual's capacity as a Manager or officer of the Company), nor any of their Affiliates or their respective successors or assigns,
shall be liable to the Company or to any Member for any claims, losses, expenses, costs, obligations, liabilities, actions, suits, proceedings, judgments, or settlements (including attorneys' fees)
(whether civil, criminal, administrative or investigative) (collectively, "Claims") arising or resulting from or relating to the performance of any of
such Manager's or officer's obligations or duties under this Agreement in its capacity as Manager or officer, or otherwise attributable to any breach of duty owed by such Manager or officer (by virtue
of being a Manager or officer) to the Company or the Members, except to the extent such Claims or breach of duty is based upon such person's fraud, bad faith or willful misconduct as established by a
non-appealable court order, judgment, decree or decision by a court of competent jurisdiction. Without limiting the generality of the foregoing, the doing of any act or the failure to do
any act by any Manager or officer, which shall not constitute fraud, bad faith or willful misconduct (as established by a non-appealable court order, judgment, decree or decision by a
court of competent jurisdiction), the effect of which may cause or result in loss or damage to the Company, shall not subject any Manager or officer to any liability. Each Manager and officer shall be
fully protected in relying in good faith upon the records of the Company and upon such information, opinions, reports or statements presented to the Company by any Person as to matters such Manager or
officer reasonably believes are within such other Person's professional or expert competence, including information, opinions, reports or statements as to the value and amount of the assets,
liabilities, profits, losses, or any other facts pertinent to the existence and amount of assets from
which distributions to Members might properly be paid. The Managers do not, in any way, guarantee the return of the Members' Capital Contributions or a profit for the Members from the operations of
the Company. No Manager shall be responsible to any Members because of a loss of their investments or a loss in operations, unless the loss shall have been the result of fraud, bad faith or willful
misconduct established as set forth in this Section 6.5.

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Section 6.6Manager Has No Exclusive Duty to Company.

A
Manager shall not be required to manage the Company as the Manager's sole and exclusive occupation, and a Manager may have other business interests and may engage in other investments,
occupations and activities in addition to those relating to the Company. Neither the Company nor any Member shall have any right, by virtue of this Agreement, to share or participate in such other
investments or activities of a Manager or to the income or proceeds derived therefrom.

Section 6.7Resignation and Withdrawal.

A
Manager of the Company may resign from the position of Manager at any time by giving written notice to the Members of the Company. The resignation of a Manager shall take effect upon
receipt of notice thereof or at such later time as shall be specified in such notice; and unless otherwise specified therein, the acceptance of such resignation shall not be necessary to make it
effective. Upon the withdrawal of a Manager, such Manager shall be treated as having resigned as of the date of withdrawal and shall automatically cease to be a Manager as of the date of such
withdrawal. Except in the case of resignation by reason of withdrawal, the resignation of a Manager who is also a Member pursuant to this Section 6.7 shall not affect such Manager's rights as a
Member and shall not constitute a withdrawal of such Member.

Section 6.8Removal.

Subject
to Section 6.2(b), a Manager may only be removed by the consent of the Member or Members then entitled to designate such Manager in accordance with Section 6.2. The
removal of a Manager who is also a Member shall not affect such Manager's rights as a Member and shall not constitute a withdrawal of such Member.

Section 6.9Vacancies.

Any
vacancy in the position of a Manager that is created by the withdrawal, death, resignation or removal of a Manager or by the creation of a new Manager position pursuant to
Section 6.2(b) shall be filled only by consent of the Member or Members then entitled to designate such Manager in accordance with Section 6.2. A Manager elected to fill a vacancy shall
hold office until a successor shall be elected and shall qualify, or until the Manager's earlier death, resignation, withdrawal or removal.

Section 6.10Delegation of Authority; Officers.

The
Board shall have the power to elect, delegate authority to, and remove such officers, employees, agents and representatives of the Company as the Board may from time to time deem
appropriate. Any delegation of authority to take any action must be approved in the same manner as would be required for the Board to approve such action directly. The salaries of all officers,
employees and agents of the Company shall be fixed by the Board in accordance with the Approved Budget.

Section 6.11Designation of Operator.



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The
Operator shall operate the Company and perform the services and activities referred to in clauses (i) through (xiii) above in accordance with Prudent Industry
Practices.



Section 6.12Approval of Members.

The
following matters shall require Requisite Member Approval (provided that an explicit approval of such matter in the Approved Budget or related Member resolution shall constitute a
Requisite Member Approval if such approval is explicitly identified as a Requisite Member Approval):



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Section 6.13Reliance by Third Parties.

Any
Person dealing with the Company, a Manager or the Operator may rely upon a certificate signed by a Manager or an appropriate officer as to:



Section 6.14Fees and Expenses of the Managers.

A
Class A Manager shall receive an annual amount of $**for serving as a Manager. A Class B Manager shall not be entitled to
any fees for serving as a Manager. A Manager shall be entitled to reimbursement for all reasonable out-of-pocket costs and expenses incurred by such Manager in the capacity as
a Manager.

Section 6.15Budgets.

By**of each calendar year following the Effective Time, the Operator shall prepare and submit the following budgets and forecasts for
the upcoming year (to the extent such budgets or forecasts are

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applicable
to such upcoming year) to the Board for approval and to the appropriate Members for Requisite Member Approval in accordance with Section 6.12:



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ARTICLE 7  ASSIGNABILITY OF MEMBER INTERESTS

Section 7.1Prohibition on Assignment During Project Period.

Prior
to**(the "Project Period"), no Member may, directly or indirectly, Transfer its
Interest or any portion thereof without the prior written consent of the other Members except for Permitted Transfers. For purposes of this Agreement, "Permitted
Transfers" shall include the following: (a) a Member may Transfer all or a portion of its Interest to any of its Affiliates, (b) Interests held by any member of
the MWE Liberty Group may be (i) Transferred, in whole or in part, in connection with any sale of all or substantially all of the assets of MWE, or (ii) indirectly Transferred by way of
a sale of Control of MWE, or any merger of MWE with or into, or any consolidation of MWE into, any other entity and (c) Interests held by NGPMR may be transferred to the limited partners of
NGPMR, if and to the extent required by the governance documents of NGPMR. In the event of a Transfer pursuant to the foregoing clause (c), the NGPMR Group shall designate a single
representative to exercise all of the NGPMR Group's rights hereunder. If a Member Transfers an Interest during the Project Period in accordance with this Section 7.1, such Transfer shall
entitle the assignee to become a Substitute Member and to exercise or receive the rights, powers or benefits of a Member if the assigning Member designates, in a written instrument delivered to the
Board and the other Members, its assignee to become a Substitute Member and such assignee executes an instrument reasonably satisfactory to the Board, which shall include an acceptance and agreement
by the Substitute Member to abide by all of the terms and conditions of this Agreement. A Member may not Transfer Interests in a Permitted Transfer if such Permitted Transfer has as a purpose the
avoidance of the restrictions on Transfers in this Agreement (it being understood that the purpose of this sentence is to prohibit the Transfer of Interests to a transferee in a Permitted Transfer
followed by a change in the relationship between the transferor and the transferee (or a change of Control of such transferor or transferee) after the Permitted Transfer with the result and effect
that the transferor has indirectly Transferred Interests to a transferee in a Transfer which would not have been directly permitted as a Permitted Transfer under this Section 7.1 had such
change in such relationship occurred prior to such Transfer).

Section 7.2Transfers After the Project Period.

After
the Project Period, a Member may Transfer its Interest, or any portion thereof, without the consent of any other Member or the Board, provided that such Member complies with the
requirements of this Section 7.2 in all instances except in connection with Permitted Transfers:



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Section 7.3Recognition of Assignment by Company or Other Members.

No
Transfer of an Interest that is in violation of this Article 7 shall be valid or effective, and neither the Company nor the Board nor any Member shall recognize the same for
any purpose of this Agreement, including the purpose of making distributions of Available Cash pursuant to this Agreement with
respect to such Interest or part thereof. Neither the Company nor the Board shall incur any liability as a result of refusing to make any such distributions to the assignee of any such invalid
assignment.

Section 7.4Effective Date of Assignment.

Any
valid Transfer of a Member's Interest, or part thereof, pursuant to the provisions of this Article 7 shall be effective as of the later of (i) the date of Transfer set
forth on the written instrument of Transfer, (ii) the date on which the Company has received the written instrument of Transfer and such other documents as may be required by the Company
pursuant to this Agreement and such Transfer has been recorded on the books of the Company, and (iii) the date on which the requirements of this Article 7 have been satisfied. The
Company shall, from the effective date of such Transfer, thereafter pay all further distributions on account of the Interest (or part thereof) so assigned to the assignee of such Interest, or part
thereof. As between any Member and its assignee, Profits and Losses for the Fiscal Year of the Company in which such assignment occurs shall be apportioned for federal income tax purposes in
accordance with any convention permitted under Section 706(d) of the Code and selected by the Board.

Section 7.5Limitations on Transfer.

No
Transfer of an Interest may be effectuated unless in the opinion of counsel satisfactory to the Board, the Transfer (a) would comply with the Securities Act and applicable
securities laws of any other jurisdiction; (b) would not cause the Company to be terminated for purposes of Code

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Section 708;
or (c) would not violate any other applicable laws, provided that the provisions of this Section 7.5 may be waived by the Board.

Section 7.6Transferee Not a Substitute Member.

In
the event that a transferee is not designated, or does not become, a Substitute Member pursuant to this Article 7, then such transferee shall not be entitled to exercise or
receive any of the rights, powers or benefits of a Member other than the right to receive distributions to which the assigning Member would be entitled.

ARTICLE 8  DISTRIBUTIONS TO MEMBERS

Section 8.1Available Cash.

Available
Cash shall be determined by the Board on a quarterly basis within 30 days after the end of each calendar quarter. Subject to the remaining provisions of this
Article 8 and any preferential or disproportionate distributions to the extent expressly provided for in this Agreement, and other than upon a liquidation of the Company pursuant to
Section 13.4, the Company shall distribute such Available Cash within 45 days following the end of each calendar quarter to the Members of record, as follows.



40

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Section 8.2Incentive Interest Percentage Distributions.

Notwithstanding
the preceding provisions in Sections 8.1(a) and (b), any Available Cash remaining after a**Payout**has occurred shall be distributed as follows:



Exhibit E
contains illustrative examples of the determination of the amounts to be distributed to NGPMR and MWE Liberty pursuant to Section**8.2**based on hypothetical distributions of Available Cash. This Section 8.2 shall be interpreted and applied in a manner consistent with the
examples set forth in Exhibit E.

Section 8.3Withholding.

All
amounts withheld pursuant to the Code or any provision of any foreign, state or local tax law or treaty with respect to any payment, distribution or allocation to the Company or the
Members shall be treated as amounts distributed to the Members pursuant to this Article 8 for all purposes of this Agreement. The Board is authorized to withhold from distributions, or with
respect to allocations, to the Members and to pay over to any federal, foreign, state or local government any amounts required
to be so withheld pursuant to the Code or any provision of any other federal, foreign, state or local law or treaty and shall allocate such amounts to those Members with respect to which such amounts
were withheld.

Section 8.4Limitations on Distribution.

Except
as provided in this Agreement, no Member shall be entitled to any distribution of cash or other property from the Company. Notwithstanding any provision to the contrary contained
in this Agreement, the Company shall not make a distribution to any Member on account of its Interest in the Company if such distribution would violate the Act or other applicable law.

Section 8.5Tax Distributions.



41

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ARTICLE 9  ALLOCATIONS

Section 9.1Profits and Losses.



Section 9.2Special Allocations.

Notwithstanding
anything in this Agreement to the contrary, the following special allocations shall be made:



42

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Section 9.3Curative Allocations.

The
allocations set forth in Section 9.2 (other than Section 9.2(f)) (the "Regulatory Allocations") are intended to comply
with certain requirements of the Treasury Regulations. It is the intent of the Members that, to the extent possible, all Regulatory Allocations shall be offset either with other Regulatory Allocations
or with special allocations of other items of Company income, gain, loss or deduction pursuant to this Section 9.3. Therefore, notwithstanding any other provision of this Article 9
(other than the Regulatory Allocations), but subject to the Code and the Treasury Regulations, the Board shall make such offsetting special allocations of Company income, gain, loss or deduction in
whatever manner it determines appropriate so that, after such offsetting allocations are made, each Member's Capital Account balance is, to the extent possible, equal to the Capital Account balance
such Member would have had if the Regulatory Allocations were not part of this Agreement. In exercising its discretion under this Section 9.3, the Board shall take into account future
Regulatory Allocations that, although not yet made, are likely to offset other Regulatory Allocations previously made.

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Section 9.4Income Tax Allocations.



Section 9.5Allocation and Other Rules.



44

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ARTICLE 10  BOOKS AND RECORDS

Section 10.1Inspection Rights Pursuant to Law.

The
Company shall have obligations to the Members as set forth in this Article 10 respecting books, records and financial statements of the Company.

Section 10.2Books and Records.

At
all times during the continuance of the Company, the Company shall maintain at its principal place of business all records and materials the Company is required to maintain at such
location under the Act. The Company shall keep proper and complete books of account adequate for its purposes. The books of account relating to the Company shall be open to inspection and copying by
any of the Members or by their authorized representatives upon reasonable notice and at any reasonable time during business hours, at the Member's expense; provided, however, that the Members
acknowledge and agree that, to the extent that the books of account include information relating to one or more Affiliates of the Operator (other than the Company) or any Out of Scope Projects or
Exempted Projects (the "Unrelated Information"), then the Company and Operator shall be entitled either to redact, or limit access to, the books of
account such that the Members shall not have access to
Unrelated Information or to require such Member to designate an independent third party auditor to conduct such review, which auditor will be required to execute a confidentiality agreement with the
Operator under which such auditor may examine the Unrelated Information but may not disclose the Unrelated Information to such Member.

Section 10.3Financial Statements and Reports.

The
Operator shall prepare, on behalf of the Company and at the Company's expense, and shall submit to the Members the following statements, reports and notices:



45

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Section 10.4Accounting Method.

For
both financial and tax reporting purposes and for purposes of determining Profits and Losses, the books and records of the Company shall be kept on such method of accounting as
determined by the Board and shall reflect all Company transactions and be appropriate and adequate for the Company's business.

Section 10.5Bank Accounts; Investments.

The
Board shall establish one or more bank accounts in the name of the Company into which all Company funds shall be deposited. No other funds shall be deposited into these accounts.

ARTICLE 11  TAX MATTERS

Section 11.1Taxation of Company.

It
is the intent of the Members that the Company shall be treated as a partnership for U.S. federal income tax purposes. Neither the Company nor any Member shall make an election for the
Company to be excluded from the application of the provisions of subchapter K of chapter 1 of subtitle A of the Code or any similar provisions of applicable state law or to be classified
as other than a partnership pursuant to Treasury Regulation Section 301.7701-3.

Section 11.2Tax Returns.

The
Company shall cause the Operator to prepare, at the expense of the Company, for each Fiscal Year (or part thereof), federal tax returns in compliance with the provisions of the Code
and any required state and local tax returns. Each Member shall furnish to the Company all pertinent information in its possession relating to the Company's operations that is necessary to enable the
Company's tax returns to be timely prepared and filed. Not less than 60 days prior to the due date (as extended) of the Company's federal income tax return or any state income tax return, the
return proposed by the Board to be filed by the Company shall be furnished to the Members for review. In addition, not more than 10 days after the date on which the Company files its federal
income tax return or any state income tax return, a copy of the return so filed shall be furnished to the Members.

Section 11.3Member Tax Return Information.

The
Company, at its expense, shall cause to be delivered to each Member within 60 calendar days after the end of the Company's taxable year an IRS Form K-1 or a good
faith estimate of the amounts to be included on such IRS Form K-1 for such Member and such other information as shall be necessary (including a statement for that year of each
Member's share of net income, net losses and other items allocated to such Member) for the preparation and timely filing by the Members of their federal, state and local income and other tax returns.

Section 11.4Tax Matters Representative.



46

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Section 11.5Right to Make Section 754 Election.

The
Board, in its sole discretion, may make or revoke, on behalf of the Company, an election in accordance with Section 754 of the Code, so as to adjust the basis of Company
property in the case of a distribution of property within the meaning of Section 734 of the Code, and in the case of a transfer of Interests within the meaning of Section 743 of the
Code.

Section 11.6Tax Elections.

The
Company shall have the right to make any U.S. federal income tax elections it deems appropriate and in the best interests of the Members.

Section 11.7Tax Reimbursement.

If
Texas law requires the Company and any Member both to participate in the filing of a Texas margin tax combined group report, and if such Member pays the margin tax liability due in
connection with such combined report, the parties agree that the Company shall promptly reimburse such Member for the margin tax paid on behalf of the Company as a combined group member. The margin
tax paid on behalf of the Company shall be equal to the margin tax that the Company would have paid if it had computed its margin tax liability for the report period on a separate entity basis rather
than as a member of the combined group. In such event, the parties agree that such Member shall be considered as paying such amount on behalf of the Company and the Company shall deduct for federal
income tax purposes 100% of the Texas margin tax attributable to the Company; provided that in the event that such deduction may not be properly taken by the Company, the Company shall reimburse such
Member for the after-tax cost of such payment of Texas margin tax paid on the Company's behalf.

ARTICLE 12  LIABILITY, EXCULPATION AND INDEMNIFICATION

Section 12.1Liability.



47

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Section 12.2Exculpation.



Section 12.3Indemnification.

To
the fullest extent permitted by applicable law, the Company shall indemnify and hold harmless each Covered Person from and against all Claims arising from or related to any act or
omission performed or omitted by such Covered Person on behalf of the Company and in a manner reasonably believed to be within the scope of authority conferred on such Covered Person by this
Agreement, except that no Covered Person shall be entitled to be indemnified in respect of any Claim by reason of such Covered Person's fraud, bad faith, or willful misconduct as established by a
non-appealable court order, judgment, decree or decision. Any indemnity under this Section 12.3 shall be provided out of and to the extent of Company assets only (including the
proceeds of any insurance policy obtained pursuant to Section 12.5), and no Covered Person shall have any personal liability on account thereof. Any amendment, modification or repeal of this
Section 12.3 or any provision in this Section 12.3 shall be prospective only and shall not in any way affect the rights of any Covered Person under this Section 12.3 as in effect
immediately prior to such amendment, modification or repeal with respect to matters occurring, in whole or in part, prior to such amendment, modification or repeal, regardless of when claims relating
to such matters may arise or be asserted.

Section 12.4Expenses.

To
the fullest extent permitted by applicable law, expenses (including legal fees) incurred by a Covered Person in defending any claim, demand, action, suit or proceeding shall, from
time to time, be advanced by the Company prior to the final disposition of such claim, demand, action, suit or proceeding upon receipt by the Company of an undertaking by or on behalf of the Covered
Person to repay such amount if it shall be determined that the Covered Person is not entitled to be indemnified as authorized in Section 12.3.

48

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Section 12.5Insurance.

The
Company may purchase and maintain insurance, to the extent and in such amounts as the Board shall, in its sole discretion, deem reasonable, on behalf of Covered Persons and such
other Persons as the Board shall determine, against any liability that may be asserted against or expenses that may be incurred by any such Person in connection with the activities of the Company or
such indemnities, regardless of whether the Company would have the power to indemnify such Person against such liability under the provisions of this Agreement. The Board and the Company may enter
into indemnity contracts with Covered Persons and such other Persons as the Board shall determine and adopt written procedures pursuant to which arrangements are made for the advancement of expenses
and the funding of obligations under Section 12.4 and containing such other procedures regarding indemnification as are appropriate.

Section 12.6Certain Liabilities.

Each
Member agrees to be liable for the Capital Contributions required to be made by such Member, and subject to the other provisions of this Agreement, in the event a Member becomes
liable for any liabilities of the Company, the Members shall bear such liability in proportion to their then existing Percentage Interests.

Section 12.7Acts Performed Outside the Scope of the Company.

Each
Member (each Member in such capacity, an "Indemnitor") shall indemnify, defend, save and hold harmless each other Member (an
"Indemnitee") from any and all Claims that shall or may arise by virtue of any act or thing done or omitted to be done by the Indemnitor (directly or
through agents or employees) outside the scope of, or in breach of, the terms of this Agreement; provided, however, that
the Indemnitor shall be properly notified of the existence of the Claim, and shall be given reasonable opportunity to cure any act or omission causing liability, and participate in the defense
thereof. The Indemnitee's failure to give such notice shall not affect the Indemnitor's obligations hereunder, except to the extent of any actual prejudice arising therefrom.

Section 12.8Liability of Members to Company or Other Members.

Unless
otherwise provided in this Agreement, no Member shall be liable to any other Member or to the Company by reason of such Member's actions in connection with the Company, except in
the event of a violation of any provision of this Agreement, fraud, bad faith or willful misconduct.

Section 12.9Attorneys' Fees.

All
of the indemnities provided in this Agreement shall include reasonable attorneys' fees, including appellate attorneys' fees and court costs.

Section 12.10Subordination of Other Rights to Indemnity.

The
interests of the Members in any proceeds of the Company by way of repayment of loans, return of any Capital Contributions, or any distributions from the Company, shall be
subordinated to the right of Members to the indemnities provided by this Article 12.

Section 12.11Survival of Indemnity Provisions.

Except
as otherwise specifically provided herein, all of the indemnity provisions contained in this Agreement shall survive a Member's ceasing to be a Member hereunder.

49

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ARTICLE 13  DISSOLUTION, LIQUIDATION AND TERMINATION

Section 13.1No Dissolution.

The
Company shall not be dissolved by the admission of Additional Members or Substitute Members in accordance with the terms of this Agreement, or the withdrawal of a Member.

Section 13.2Events Causing Dissolution.

The
Company shall be dissolved and its affairs shall be wound up upon the occurrence of any of the following events:



Section 13.3Notice of Dissolution.

Upon
the dissolution of the Company, the Board shall promptly notify the Members of such dissolution.

Section 13.4Liquidation.



50

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Section 13.5Termination.

The
Company shall terminate when all of the assets of the Company, after payment of or due provision for all debts, liabilities and obligations of the Company, shall have been
distributed to the Members in the manner provided for in this Article 13 and the Certificate shall have been canceled, or such other documents required under the Act to be executed and filed
with the Secretary of State of the State of Delaware have been so executed and filed, in the manner required by the Act.

Section 13.6Claims of the Members or Third Parties.

The
Members and former Members shall look solely to the Company's assets for the return of their Capital Contributions, and if the assets of the Company remaining after payment of or due
provision for all debts, liabilities and obligations of the Company are insufficient to return such Capital Contributions, the Members and former Members shall have no recourse against the Company or
any other Member; provided, however, that nothing contained herein shall be deemed to limit the rights of a Member under applicable law. In the event any Member has a deficit balance in its Capital
Account at the time of the Company's dissolution, it shall not be required to restore such account to a positive balance or otherwise make any payments to the Company or its creditors or other third
parties in respect of such deficiency.

Section 13.7Distributions In-Kind.

If
any assets of the Company shall be distributed in kind, such assets shall be distributed to the Member(s) entitled thereto as tenants-in-common in the same
proportions as such Member(s) would have been entitled to cash distributions if (i) such assets had been sold for cash by the Company at the fair market value of such property (taking the Gross
Asset Value definition herein and Code Section 7701(g) into account) on the date of distribution; (ii) any unrealized income, gain, loss and deduction inherent in such property (that has
not been reflected in the Capital Accounts previously) that would be realized by the Company from such sale were allocated among the Member(s) as Profits or Losses in accordance with this Agreement;
and (iii) the cash proceeds were distributed to the Member(s) in accordance with this Article 13. The Capital Accounts of the Member(s) shall be increased by the amount of any unrealized
income or gain inherent in such property or decreased by the amount of any loss or deduction inherent in such property that would be allocable to them, and shall be reduced by the fair market value of
the assets distributed to them under the preceding sentence. Notwithstanding the foregoing, the Members shall have the right to assign their interest to such in-kind distribution to any
Person.

51

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ARTICLE 14  REPRESENTATIONS, WARRANTIES AND COVENANTS

Section 14.1Representations, Warranties and Covenants.

Each
Member hereby represents, warrants and covenants to the Company as follows:



52

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ARTICLE 15  MISCELLANEOUS

Section 15.1Notices.

All
notices provided for in this Agreement shall be in writing, duly signed by the party giving such notice, and shall be delivered, telecopied, mailed by registered or certified mail,
sent by recognized overnight delivery or courier service (e.g., Federal Express) or, to the extent permitted by this Agreement, sent via electronic mail, and shall be deemed to have been given
upon delivery, if delivered personally or by facsimile or electronic mail, three days after mailing, if mailed, or one Business Day after delivery to the courier, if delivered by overnight courier
service, as follows:



Section 15.2Failure to Pursue Remedies.

The
failure of any party to seek redress for violation of, or to insist upon the strict performance of, any provision of this Agreement shall not prevent a subsequent act, which would
have originally constituted a violation, from having the effect of an original violation.

Section 15.3Cumulative Remedies.

The
rights and remedies provided by this Agreement are cumulative and the use of any one right or remedy by any party shall not preclude or waive its right to use any or all other
remedies. Said rights and remedies are given in addition to any other rights the parties may have by law, statute, ordinance or otherwise.

Section 15.4Binding Effect.

This
Agreement shall be binding upon and inure to the benefit of all of the parties and, to the extent permitted by this Agreement, their successors, legal representatives and assigns.

53

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Section 15.5Interpretation.

Throughout
this Agreement, nouns, pronouns and verbs shall be construed as masculine, feminine, neuter, singular or plural, whichever shall be applicable. All references herein to
"Articles," "Sections" and "Paragraphs" shall refer to corresponding provisions of this Agreement.

Section 15.6Severability.

The
invalidity or unenforceability of any particular provision of this Agreement shall not affect the other provisions hereof, and this Agreement shall be construed in all respects as if
such invalid or unenforceable provision were omitted.

Section 15.7Counterparts.

This
Agreement may be executed in any number of counterparts with the same effect as if all parties hereto had signed the same document. All counterparts shall be construed together and
shall constitute one instrument.

Section 15.8Integration.

This
Agreement constitutes the entire agreement among the parties hereto pertaining to the subject matter hereof and supersedes all prior agreements and understandings pertaining
thereto.

Section 15.9Amendment or Restatement.

This
Agreement (including any Exhibit or Schedule hereto) and the Certificate may be amended, modified or supplemented, and any provisions of this Agreement or the Certificate be waived,
with a written instrument adopted, executed and agreed to by the Company and the Class B Members with an aggregate Class B Percentage Interest equal to or exceeding 50%; provided,
however, that (a) this Agreement shall be deemed automatically amended from time to time without further consent of any party to reflect issuances and transfers of Interests made in compliance
with this Agreement and (b) any amendment, modification, supplement or waiver to this Agreement or the Certificate that would adversely affect the rights, or increase the obligations, of any
Member in any material respect shall not be effective without the consent of such affected Member. Except as required by law, no amendment, modification, supplement, discharge or waiver of or under
this Agreement shall require the consent of any Person not a party to this Agreement.

Section 15.10Governing Law.

This
Agreement and the rights of the parties hereunder shall be interpreted in accordance with the laws of the State of Delaware and all rights and remedies shall be governed by such
laws without regard to principles of conflict of laws. The parties further agree that any legal action or proceeding with respect to this Agreement or any document relating hereto may be brought only
in a federal or state court of competent jurisdiction in Houston, Texas. Each party hereby irrevocably waives any objection, including, without limitation, any objection to the laying of venue or
based on the grounds of
forum non-convenience, which it may now or hereafter have to the bringing of such action or proceeding in any such respective jurisdiction.

Section 15.11Dealings in Good Faith.

Except
as otherwise expressly set forth herein, each party hereto agrees to act in good faith with respect to the other party in exercising its rights and discharging its obligations
under this Agreement. Each party further agrees to use its reasonable efforts to ensure that the purposes of this Agreement are realized and to take all steps as are reasonable in order to implement
the operational provisions of this Agreement.

54

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Section 15.12Partition of the Property.

Each
Member agrees that it shall have no right to partition the Property, or any portion thereof, and each Member agrees that it shall not make application to any court or authority
having jurisdiction in the matter to commence or prosecute any action or proceeding for partition of the Property, or any portion thereof. Upon the breach of this Section by any Member, the other
Members, in addition to all other rights and remedies in law and equity, shall be entitled to a decree or order dismissing application, action or proceeding.

Section 15.13Third Party Beneficiaries.

Except
as expressly set forth in this Agreement, nothing in this Agreement is intended or shall be construed, to confer upon or give any Person other than the parties hereto, any rights,
remedies, obligations or liabilities under or by reason of this Agreement, or result in their being deemed a third party beneficiary of this Agreement.

Section 15.14Tax Disclosure Authorization.

Notwithstanding
anything herein to the contrary, the Members (and each Affiliate and Person acting on behalf of any Member) agree that each Member (and each employee, representative, and
other agent
of such Member) may disclose to any and all Persons, without limitation of any kind, the transaction's tax treatment and tax structure (as such terms are used in Sections 6011 and 6112 of the
Code and the Treasury Regulations thereunder) contemplated by this Agreement and all materials of any kind (including opinions or other tax analyses) provided to such Member or such Person relating to
such tax treatment and tax structure, except to the extent necessary to comply with any applicable federal or state securities laws.

Section 15.15Waivers and Consents.

A
waiver or consent, express or implied, to or of any breach or default by any Person in the performance of its obligations hereunder is not a consent or waiver to or of any other breach
or default in the performance by that Person of the same or any other obligation of such Person hereunder. Failure of a Person to assert the default or breach of any other Person hereunder shall not
constitute a waiver thereof until the applicable statute of limitations period has run.

Section 15.16Deadlocks; Negotiations.



55

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Section 15.17Dispute Resolution.



56

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57

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Section 15.18Transaction Expenses.



[Signature
Page Follows]

58

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first above written.

MWE LIBERTY:MARKWEST LIBERTY GAS GATHERING, L.L.C.,
a Delaware limited liability companyBy:

/s/ Frank M. SempleName:

Frank M. SempleTitle:

President and CEOAddress for notice:
1515 Arapahoe Street
Tower 2, Suite 700
Denver, CO 80202-2126
Attention: Senior Vice President and Chief Operations OfficerNGPMR:M&R MWE LIBERTY, LLCBy:

/s/ John T. RaymondName:

John T. RaymondTitle:

CEO & Managing PartnerAddress for notice:
1401 McKinney, Suite 1025
Houston, TX 77010
Attention: Jeffrey C. Rawlswith a copy to:Locke Lord Bissell & Liddell, LLP
600 Travis Street, Suite 3400
Houston, Texas 77002
Fax (713) 229-2518
Attention: H. William Swanstrom


Signature
Page

---



EXHIBIT A

AREA
OF MUTUAL INTEREST

The
areas described on the attached Area of Mutual Interest Map.

A-1

---



**

A-2

---





EXHIBIT B    MEMBERS AND CAPITAL CONTRIBUTIONS(1)

Member Name and Address

Aggregate Capital
Contributions

Cash Capital
Contributions

Type of
Membership
Interest

Percentage
Interest

Investment
BalanceM&R MWE Liberty, LLC

$
**

$
**


Class A


40%

$
**1401 McKinney, Suite 1025Houston, TX 77010Attention: Jeffrey C. RawlsFacsimile: (713) 579-5017Email: jrawls@ngpmr.comwith a copy to:Locke Lord Bissell & Liddell, LLP600 Travis Street, Suite 3400Houston, Texas 77002Fax (713) 229-2518Attention: H. William SwanstromMarkWest Liberty Gas Gathering, L.L.C.

$
**

$
**


Class B


60%

$
**1515 Arapahoe Street, Tower 2Suite 700Denver, CO 80202Attention: Senior Vice President and Chief Operations OfficerFacsimile: (303) 925-9305Email: jmollenkopf@markwest.comwith a copy to:MarkWest Liberty Gas Gathering, L.L.C.1515 Arapahoe Street, Tower 2Suite 700Denver, CO 80202Attention: Senior Vice President, General Counsel and SecretaryFacsimile: (303) 925-9308Email: cbromley@markwest.com


(1)Aggregate
Capital Contributions, Cash Capital Contributions and Investment Balances determined as of October 1, 2009.


B-1

---



EXHIBIT C

BASE
PROJECT

**

**

**

C-1

---



EXHIBIT D

INITIAL
BUDGET

(See
attached)

**

[2
pages have been omitted and filed separately with the Securities and Exchange Commission pursuant to the request for confidential treatment.]

D-1

---



EXHIBIT E

ILLUSTRATIVE
EXAMPLE CALCULATION OF INCENTIVE INTERESTS

**

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

E-1

---



EXHIBIT G

CAPITAL
EXPENDITURES FOR AGREEMENTS

**

G-1

---



EXHIBIT H

PRE-APPROVED
AFFILIATED TRANSACTIONS

H-1

---



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