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Exhibit 4.2  

MARKWEST ENERGY PARTNERS, L.P.,  

 MARKWEST ENERGY FINANCE CORPORATION, as Issuers,  

 THE SUBSIDIARIES NAMED HEREIN, as Subsidiary Guarantors  

 AND  

 WELLS FARGO BANK, NATIONAL ASSOCIATION, as Trustee  

 6.875% Series A Senior Notes due 2014  

 6.875% Series B Senior Notes due 2014  

  
 

    INDENTURE    
    

Dated as of October 25, 2004  

CROSS-REFERENCE TABLE*  

	Trust Indenture Act Section
 
	 	Indenture

Section(s)

	310	 	(a)(1)	 	7.10
	 	 	(a)(2)	 	7.10
	 	 	(a)(3)	 	N.A.
	 	 	(a)(4)	 	N.A.
	 	 	(a)(5)	 	7.10
	 	 	(b)	 	7.10
	 	 	(c)	 	N.A.
	311	 	(a)	 	7.11
	 	 	(b)	 	7.11
	 	 	(c)	 	N.A.
	312	 	(a)	 	2.05
	 	 	(b)	 	12.03
	 	 	(c)	 	12.03
	313	 	(a)	 	7.06
	 	 	(b)(1)	 	N.A.
	 	 	(b)(2)	 	7.06
	 	 	(c)	 	7.06; 12.02
	 	 	(d)	 	7.06
	314	 	(a)	 	4.03; 4.18; 12.02
	 	 	(b)	 	N.A.
	 	 	(c)(1)	 	12.04
	 	 	(c)(2)	 	12.04
	 	 	(c)(3)	 	N.A.
	 	 	(d)	 	N.A.
	 	 	(e)	 	12.05
	 	 	(f)	 	N.A.
	315	 	(a)	 	7.01
	 	 	(b)	 	7.05; 12.02
	 	 	(c)	 	7.01
	 	 	(d)	 	7.01; 6.05
	 	 	(e)	 	6.11
	316	 	(a)(last sentence)	 	2.09
	 	 	(a)(1)(A)	 	6.05
	 	 	(a)(1)(B)	 	6.04
	 	 	(a)(2)	 	N.A.
	 	 	(b)	 	6.07
	 	 	(c)	 	9.04
	317	 	(a)(1)	 	6.08
	 	 	(a)(2)	 	6.09
	 	 	(b)	 	2.04
	318	 	(a)	 	12.01
	 	 	(b)	 	N.A.
	 	 	(c)	 	12.01

N.A.
means not applicable. 

*This
Cross-Reference Table is not part of the Indenture. 

   TABLE OF CONTENTS  

	 
	 	Page

	ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE	 	1
	 	Section 1.01. Definitions	 	1
	 	Section 1.02. Other Definitions	 	21
	 	Section 1.03. Incorporation by Reference of Trust Indenture Act	 	21
	 	Section 1.04. Rules of Construction	 	22
	
ARTICLE 2 THE NOTES	
 	

22
	 	Section 2.01. Form and Dating	 	22
	 	Section 2.02. Execution and Authentication	 	23
	 	Section 2.03. Registrar and Paying Agent	 	23
	 	Section 2.04. Paying Agent to Hold Money in Trust	 	24
	 	Section 2.05. Holder Lists	 	24
	 	Section 2.06. Transfer and Exchange	 	24
	 	Section 2.07. Replacement Notes	 	31
	 	Section 2.08. Outstanding Notes	 	32
	 	Section 2.09. Treasury Notes	 	32
	 	Section 2.10. Temporary Notes	 	32
	 	Section 2.11. Cancellation	 	32
	 	Section 2.12. Defaulted Interest	 	32
	 	Section 2.13. CUSIP Numbers	 	33
	
ARTICLE 3 REDEMPTION AND PREPAYMENT	
 	

33
	 	Section 3.01. Notices to Trustee	 	33
	 	Section 3.02. Selection of Notes to Be Redeemed	 	33
	 	Section 3.03. Notice of Redemption	 	34
	 	Section 3.04. Effect of Notice of Redemption	 	34
	 	Section 3.05. Deposit of Redemption Price	 	34
	 	Section 3.06. Notes Redeemed in Part	 	35
	 	Section 3.07. Optional Redemption	 	35
	 	Section 3.08. Mandatory Redemption	 	36
	 	Section 3.09. Offer to Purchase by Application of Net Proceeds	 	36
	
ARTICLE 4 COVENANTS	
 	

37
	 	Section 4.01. Payment of Notes	 	37
	 	Section 4.02. Maintenance of Office or Agency	 	38
	 	Section 4.03. Compliance Certificate	 	38
	 	Section 4.04. Taxes	 	38
	 	Section 4.05. Stay, Extension and Usury Laws	 	39
	 	Section 4.06. Change of Control	 	39
	 	Section 4.07. Asset Sales	 	40
	 	Section 4.08. Restricted Payments	 	42
	 	Section 4.09. Incurrence of Indebtedness and Issuance of Disqualified Equity	 	44
	 	Section 4.10. Liens	 	46
	 	Section 4.11. Dividend and Other Payment Restrictions Affecting Subsidiaries	 	47
	 	Section 4.12. Transactions With Affiliates	 	48
	 	Section 4.13. Additional Subsidiary Guarantees	 	49
	 	Section 4.14. Designation of Restricted and Unrestricted Subsidiaries	 	49
	 	Section 4.15. Business Activities	 	50
	 	Section 4.16. Sale and Leaseback Transactions	 	50
	 	Section 4.17. Payments for Consent	 	50
	 	 	 

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	 	Section 4.18. Reports	 	50
	 	Section 4.19. Suspension of Covenants	 	51
	
ARTICLE 5 SUCCESSORS	
 	

52
	 	Section 5.01. Merger, Consolidation, or Sale of Assets	 	52
	 	Section 5.02. Successor Entity Substituted	 	53
	
ARTICLE 6 DEFAULTS AND REMEDIES	
 	

54
	 	Section 6.01. Events of Default	 	54
	 	Section 6.02. Acceleration	 	55
	 	Section 6.03. Other Remedies	 	56
	 	Section 6.04. Waiver of Past Defaults	 	56
	 	Section 6.05. Control by Majority	 	56
	 	Section 6.06. Limitation on Suits	 	56
	 	Section 6.07. Rights of Holders of Notes to Receive Payment	 	57
	 	Section 6.08. Collection Suit by Trustee	 	57
	 	Section 6.09. Trustee May File Proofs of Claim	 	57
	 	Section 6.10. Priorities	 	57
	 	Section 6.11. Undertaking for Costs	 	58
	
ARTICLE 7 TRUSTEE	
 	

58
	 	Section 7.01. Duties of Trustee	 	58
	 	Section 7.02. Rights of Trustee	 	59
	 	Section 7.03. Individual Rights of Trustee	 	60
	 	Section 7.04. Trustee's Disclaimer	 	60
	 	Section 7.05. Notice of Defaults	 	61
	 	Section 7.06. Reports by Trustee to Holders of the Notes	 	61
	 	Section 7.07. Compensation and Indemnity	 	61
	 	Section 7.08. Replacement of Trustee	 	62
	 	Section 7.09. Successor Trustee by Merger, Etc.	 	63
	 	Section 7.10. Eligibility; Disqualification	 	63
	 	Section 7.11. Preferential Collection of Claims Against Issuers	 	63
	
ARTICLE 8 LEGAL DEFEASANCE AND COVENANT DEFEASANCE	
 	

63
	 	Section 8.01. Option to Effect Legal Defeasance or Covenant Defeasance	 	63
	 	Section 8.02. Legal Defeasance and Discharge	 	63
	 	Section 8.03. Covenant Defeasance	 	64
	 	Section 8.04. Conditions to Legal Defeasance or Covenant Defeasance	 	64
	 	Section 8.05. Deposited Money and Government Securities to be Held in Trust, Other Miscellaneous Provisions	 	65
	 	Section 8.06. [Intentionally omitted]	 	66
	 	Section 8.07. Reinstatement	 	66
	
ARTICLE 9 AMENDMENT, SUPPLEMENT AND WAIVER	
 	

66
	 	Section 9.01. Without Consent of Holders of Notes	 	66
	 	Section 9.02. With Consent of Holders of Notes	 	67
	 	Section 9.03. Compliance with Trust Indenture Act	 	68
	 	Section 9.04. Revocation and Effect of Consents	 	68
	 	Section 9.05. Notation or Exchange of Notes	 	69
	 	Section 9.06. Trustee to Sign Amendments, Etc.	 	69
	 	Section 9.07. Effect of Supplemental Indentures	 	69
	 	 	 

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ARTICLE 10 GUARANTEES	
 	

69
	 	Section 10.01. Guarantees	 	69
	 	Section 10.02. Limitation of Guarantor's Liability	 	70
	 	Section 10.03. Execution and Delivery of Notations of Guarantees	 	71
	 	Section 10.04. [Intentionally omitted]	 	71
	 	Section 10.05. Releases	 	71
	 	Section 10.06. "Trustee" to Include Paying Agent	 	71
	
ARTICLE 11 SATISFACTION AND DISCHARGE	
 	

72
	 	Section 11.01. Satisfaction and Discharge	 	72
	 	Section 11.02. Application of Trust	 	73
	 	Section 11.03. Repayment of the Issuers	 	73
	 	Section 11.04. Reinstatement	 	73
	
ARTICLE 12 MISCELLANEOUS	
 	

74
	 	Section 12.01. Trust Indenture Act Controls	 	74
	 	Section 12.02. Notices	 	74
	 	Section 12.03. Communication by Holders of Notes with Other Holders of Notes	 	75
	 	Section 12.04. Certificate and Opinion as to Conditions Precedent	 	75
	 	Section 12.05. Statements Required in Certificate or Opinion	 	76
	 	Section 12.06. Rules by Trustee and Agents	 	76
	 	Section 12.07. No Personal Liability of Directors, Officers, Employees and Unitholders and No Recourse Against General Partner	 	76
	 	Section 12.08. Governing Law	 	76
	 	Section 12.09. No Adverse Interpretation of Other Agreements	 	76
	 	Section 12.10. Successors	 	76
	 	Section 12.11. Severability	 	76
	 	Section 12.12. Counterpart Originals	 	77
	 	Section 12.13. Table of Contents, Headings, Etc.	 	77

SCHEDULES, EXHIBITS AND ANNEXES  

	SCHEDULE A	 	Schedule of Subsidiary Guarantors	 	 
	

SCHEDULE B	
 	

Certain Agreements	
 	

 
	

EXHIBIT A	
 	

Form of Note	
 	

Exhibit A Page 1
	

EXHIBIT B	
 	

Form of Certificate of Transfer	
 	

Exhibit B Page 1
	

EXHIBIT C	
 	

Form of Certificate of Exchange	
 	

Exhibit C Page 1
	

EXHIBIT D	
 	

Form of Guarantee Notation	
 	

Exhibit D Page 1
	

EXHIBIT E	
 	

Form of Certificates from Acquiring Institutional Accredited Investor	
 	

Exhibit E Page 1
	

ANNEX A	
 	

Form of Supplemental Indenture	
 	

A-1
	

ANNEX B	
 	

Form of Registration Rights Agreement	
 	

B-1

iii

   
        THIS INDENTURE dated as of October 25, 2004 is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the "Partnership"), MarkWest Energy Finance Corporation, a
Delaware corporation ("MarkWest Finance" and, collectively with the Partnership, the "Issuers"), the Subsidiary Guarantors (as defined herein) listed on Schedule A hereto, and Wells Fargo Bank,
National Association, a national banking association, as trustee (the "Trustee"). 

        The
Issuers, the Subsidiary Guarantors, and the Trustee agree as follows for the benefit of each other and for the equal and ratable benefit of the Holders of the 6.875% Series A
Senior Notes due 2014 (the "Series A Notes") and the 6.875% Series B Senior Notes due 2014 (the "Exchange Notes" and, together with the Series A Notes, the "Notes"): 

ARTICLE 1

DEFINITIONS AND INCORPORATION BY REFERENCE  

Section 1.01.
Definitions. 

        "144A Global Note" means the Global Note in the form of Exhibit A hereto bearing the Global Note Legend and the
Private Placement Legend and that has the "Schedule of Exchange of Interests in the Global Note" attached thereto and deposited with and registered in the name of the Depositary or its nominee that
will be issued in a denomination equal to the outstanding principal amount of the Notes sold in reliance on Rule 144A, subject to adjustment as provided in Section 2.06 hereof. 

        "Acquired Debt" means, with respect to any specified Person: (1) Indebtedness of any other Person existing at the time such other
Person is merged with or into or became a Subsidiary of such specified Person, whether or not such Indebtedness is incurred in connection with, or in contemplation of, such other Person merging with
or into, or becoming a Subsidiary of, such specified Person, but excluding Indebtedness that is extinguished, retired or repaid in connection with such Person merging with or becoming a Subsidiary of
such specified Person; and (2) Indebtedness secured by a Lien encumbering any asset acquired by such specified Person. 

        "Additional Interest" means all additional interest then owing pursuant to a Registration Rights Agreement. Unless the context indicates
otherwise, all references to "interest" in this Indenture or the Notes shall be deemed to include any Additional Interest. 

        "Affiliate" of any specified Person means any other Person directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified Person. For purposes of this definition, "control," as used with respect to any Person, shall mean the possession, directly or indirectly, of the power to direct or
cause the direction of the management or policies of such Person, whether through the ownership of voting securities, by agreement or otherwise; provided that beneficial ownership of 10% or more of
the Voting Stock of a specified Person shall be deemed to be control by the other Person; provided, further, that any third Person which also beneficially owns 10% or more of the Voting Stock of a
specified Person shall not be deemed to be an Affiliate of either the specified Person or the other Person merely because of such common ownership in such specified Person. For purposes of this
definition, the terms "controlling," "controlled by" and "under common control with" shall have correlative meanings. Notwithstanding the preceding, the term "Affiliate" shall not include a Restricted
Subsidiary of any specified Person. 

        "Agent" means any Registrar or Paying Agent. 

        "Applicable Procedures" means, with respect to any transfer or exchange of or for beneficial interests in any Global Note, the rules and
procedures of the Depositary, Euroclear and Clearstream that apply to such transfer or exchange. 

1

 

        "Asset Sale" means: 

        (1)   the
sale, lease, conveyance or other disposition of any assets, other than sales of inventory in the ordinary course of business; provided that the sale, lease,
conveyance or other disposition of all or substantially all of the assets of the Partnership and its Restricted Subsidiaries taken as a whole will be governed by the provisions of Section 4.06
and/or the provisions of Article 5 hereof and not by the provisions of Section 4.07; and 

        (2)   the
issuance of Equity Interests by any of the Partnership's Restricted Subsidiaries or the sale by the Partnership or any of its Restricted Subsidiaries of Equity
Interests in any of its Restricted Subsidiaries. 

        Notwithstanding
the preceding, the following items shall not be deemed to be Asset Sales: 

        (1)   any
single transaction or series of related transactions that: (a) involves assets having a fair market value of less than $1.0 million; or
(b) results in net proceeds to the Partnership and its Restricted Subsidiaries of less than $1.0 million; 

        (2)   a
transfer of assets between or among the Partnership and its Restricted Subsidiaries; 

        (3)   an
issuance of Equity Interests by a Restricted Subsidiary to the Partnership or to another Restricted Subsidiary of the Partnership; 

        (4)   a
Restricted Payment that is permitted under Section 4.08 hereof or a Permitted Investment; 

        (5)   the
sale or other disposition of cash or Cash Equivalents, Hedging Obligations or other financial instruments in the ordinary course of business; 

        (6)   any
trade or exchange by the Partnership or any of its Restricted Subsidiaries of properties or assets for properties or assets owned or held by another Person, provided
that the fair market value of the properties or assets traded or exchanged by the Partnership or such Restricted Subsidiary (together with any cash) is reasonably equivalent to the fair market value
of the properties or assets (together with any cash) to be received by the Partnership or such Restricted Subsidiary, and provided further that any cash received must be applied in accordance with the
provisions of Section 4.07 hereof; 

        (7)   surrender
or waiver of contract rights or the settlement, release or surrender of contract, tort or other claims of any kind; 

        (8)   the
creation or perfection of a Lien that is not prohibited by Section 4.10; 

        (9)   dispositions
in connection with Permitted Liens; and 

        (10) the
grant in the ordinary course of business of any non-exclusive license of patents, trademarks, registrations therefor and other similar intellectual
property. 

        "Attributable Debt" in respect of a sale and lease-back transaction means, at the time of determination, the present value of
the obligation of the lessee for net rental payments during the remaining term of the lease included in such sale and lease-back transaction, including any period for which such lease has
been extended or may, at the option of the lessor, be extended. Such present value shall be calculated using a discount rate equal to the rate of interest implicit in such transaction, determined in
accordance with GAAP. 

        "Available Cash" has the meaning assigned to such term in the Partnership Agreement, as in effect on the Issue Date. 

        "Bankruptcy Law" means Title 11, U.S. Code or any similar federal or state law for the relief of debtors. 

2

 

        "Beneficial Owner" has the meaning assigned to such term in Rule 13d-3 and Rule 13d-5 under the
Exchange Act, except that in calculating the beneficial ownership of any particular "person" (as that term is used in Section 13(d)(3) of the Exchange Act), such "person" will be deemed
to have beneficial ownership of all securities that such "person" has the right to acquire by conversion or exercise of other securities, whether such right is currently exercisable or is exercisable
only upon the occurrence of a subsequent condition. The terms "Beneficially Owns" and "Beneficially Owned" have correlative meanings. 

        "Board of Directors" means, with respect to the Partnership, the Board of Directors of the General Partner, or any authorized committee of
such Board of Directors, and with respect to MarkWest Finance or any other Subsidiary of the Partnership, the Board of Directors or managing members of such Person. 

        "Board Resolution" means a copy of a resolution certified by the Secretary or an Assistant Secretary of the applicable Person to have been
duly adopted by the Board of Directors of such Person and to be in full force and effect on the date of such certification, and delivered to the Trustee. 

        "Business Day" means any day other than a Legal Holiday. 

        "Capital Lease Obligation" means, at the time any determination thereof is to be made, the amount of the liability in respect of a capital
lease that would at that time be required to be capitalized on a balance sheet in accordance with GAAP. 

        "Cash Equivalents" means: 

        (1)   United
States dollars or, in an amount up to the amount necessary or appropriate to fund local operating expenses, other currencies; 

        (2)   securities
issued or directly and fully guaranteed or insured by the United States government or any agency or instrumentality thereof (provided that the full faith and
credit of the United States is pledged in support thereof) having maturities of not more than one year from the date of acquisition; 

        (3)   certificates
of deposit, time deposits and eurodollar time deposits with maturities of one year or less from the date of acquisition, bankers' acceptances with
maturities not exceeding 365 days, demand and overnight bank deposits and other similar types of investments routinely offered by commercial banks, in each case, with any domestic commercial
bank having a combined capital and surplus in excess of $500.0 million and a Thompson Bank Watch Rating of "B" or better or any commercial bank of any other country that is a member of the
Organization for Economic Cooperation and Development ("OECD") and has total assets in excess of $500.0 million; 

        (4)   repurchase
obligations with a term of not more than seven days for underlying securities of the types described in clauses (2) and (3) above entered
into with any financial institution meeting the qualifications specified in clause (3) above; 

        (5)   commercial
paper having one of the two highest ratings obtainable from Moody's or Standard & Poor's and in each case maturing within six months after the
date of acquisition; and 

        (6)   money
market funds at least 95% of the assets of which constitute Cash Equivalents of the kinds described in clauses (1) through (5) of this definition. 

        "Certificated Note" means a certificated Note registered in the name of the Holder thereof and issued in accordance with
Section 2.06 hereof, in the form of Exhibit A hereto, except that such Note shall not bear the Global Note Legend, shall not have the phrase identified by footnote 3 thereto and
shall not have the "Schedule of Exchanges of Interests in the Global Note" attached thereto. 

3

 

        "Change of Control" means the occurrence of any of the following: 

        (1)   the
direct or indirect sale, lease, transfer, conveyance or other disposition (other than by way of merger or consolidation), in one or a series of related transactions,
of all or substantially all of the properties or assets (including Equity Interests of the Restricted Subsidiaries) of the Partnership and its Restricted Subsidiaries taken as a whole, to any "person"
(as that term is used in Section 13(d)(3) of the Exchange Act); 

        (2)   the
adoption of a plan relating to the liquidation or dissolution of the Partnership or the removal of the General Partner by the limited partners of the Partnership; 

        (3)   the
consummation of any transaction (including, without limitation, any merger or consolidation) the result of which is that any "person" (as that term is used in
Section 13(d)(3) of the Exchange Act), excluding the MarkWest Hydrocarbon Group, becomes the Beneficial Owner, directly or indirectly, of more than 50% of the Voting Stock of the General
Partner, measured by voting power rather than number of shares; 

        (4)   the
consummation of any transaction (including, without limitation, any merger or consolidation) the result of which is that any "person" (as that term is used in
Section 13(d)(3) of the Exchange Act), excluding the Persons referred to in clause (1) of the definition of "MarkWest Hydrocarbon Group," becomes the Beneficial Owner,
directly or indirectly, of more than 50% of the Voting Stock of MarkWest Hydrocarbon, measured by voting power rather than number of shares, at a time when MarkWest Hydrocarbon still Beneficially Owns
more than 50% of the Voting Stock of the General Partner, measured by voting power rather than number of shares; or 

        (5)   the
first day on which a majority of the members of the Board of Directors of the General Partner are not Continuing Directors. 

Notwithstanding
the preceding, a conversion of the Partnership from a limited partnership to a corporation, limited liability company or other form of entity or an exchange of all of the outstanding
limited partnership interests for capital stock in a corporation, for member interests in a limited liability company or for Equity Interests in such other form of entity shall not constitute a Change
of Control, so long as following such conversion or exchange the MarkWest Hydrocarbon Group Beneficially Owns, directly or indirectly, in the aggregate more than 50% of the Voting Stock of such
entity, or continues to own a sufficient percentage of Voting Stock of such entity to elect a majority of its directors, managers, trustees or other persons serving in a similar capacity for such
entity. 

        "Clearstream" means Clearstream Banking, S.A. or any successor securities clearing agency. 

        "Code" means the Internal Revenue Code of 1986, as amended from time to time, and the rules and regulations thereunder, and any successor
thereto. 

        "Consolidated Cash Flow" means, with respect to any Person for any period, the Consolidated Net Income of such Person for such period
plus: 

        (1)   an
amount equal to the dividends or distributions paid during such period in cash or Cash Equivalents to such Person or any of its Restricted Subsidiaries by a Person
that is not a Restricted Subsidiary of such Person; plus 

        (2)   an
amount equal to any extraordinary loss of such Person and its Restricted Subsidiaries plus any net loss realized by such Person and its Restricted Subsidiaries in
connection with an Asset Sale, to the extent such losses were deducted in computing such Consolidated Net Income; plus 

        (3)   the
provision for taxes based on income or profits of such Person and its Restricted Subsidiaries for such period, to the extent that such provision for taxes was
deducted in computing such Consolidated Net Income; plus 

4

 

        (4)   the
consolidated interest expense of such Person and its Restricted Subsidiaries for such period, whether paid or accrued (including, without limitation, amortization of
debt issuance costs and original issue discount, non-cash interest payments, the interest component of any deferred payment obligations, the interest component of all payments associated
with Capital Lease Obligations, imputed interest with respect to Attributable Debt, commissions, discounts and other fees and charges incurred in respect of letter of credit or bankers' acceptance
financings, and net of the effect of all
payments made or received pursuant to interest-rate Hedging Obligations), to the extent that any such expense was deducted in computing such Consolidated Net Income; plus 

        (5)   depreciation,
depletion and amortization (including amortization of goodwill and other intangibles but excluding amortization of prepaid cash expenses that were paid in
a prior period) and other non-cash expenses (excluding any such non-cash expense to the extent that it represents an accrual of or reserve for cash expenses in any future
period or amortization of a prepaid cash expense that was paid in a prior period) of such Person and its Restricted Subsidiaries for such period to the extent that such depreciation, depletion,
amortization and other non-cash expenses were deducted in computing such Consolidated Net Income; minus 

        (6)   non-cash
items increasing such Consolidated Net Income for such period, other than items that were accrued in the ordinary course of business, in each case,
on a consolidated basis and determined in accordance with GAAP. 

Notwithstanding
the preceding, the provision for taxes based on the income or profits of, and the depreciation, depletion and amortization and other non-cash charges of, a Restricted
Subsidiary of the Partnership shall be added to Consolidated Net Income to compute Consolidated Cash Flow of the Partnership only to the extent that a corresponding amount would be permitted at the
date of determination to be dividended or distributed to the Partnership by such Restricted Subsidiary without prior approval (that has not been obtained), pursuant to the terms of its charter and all
agreements (other than this Indenture, the Notes or its Guarantee), instruments, judgments, decrees, orders, statutes, rules and governmental regulations applicable to that Restricted Subsidiary or
its stockholders, partners or members. 

        "Consolidated Net Income" means, with respect to any specified Person for any period, the aggregate of the Net Income of such Person and
its Restricted Subsidiaries for such period, on a consolidated basis, determined in accordance with GAAP; provided that: 

        (1)   the
aggregate Net Income (but not net loss in excess of such aggregate Net Income) of all Persons that are Unrestricted Subsidiaries shall be excluded (without
duplication); 

        (2)   the
earnings included therein attributable to all entities that are accounted for by the equity method of accounting and the aggregate Net Income (but not net loss in
excess of such aggregate Net Income) included therein attributable to all entities constituting Joint Ventures that are accounted for on a consolidated basis (rather than by the equity method of
accounting) shall be excluded; 

        (3)   the
Net Income of any Restricted Subsidiary shall be excluded to the extent that the declaration or payment of dividends or similar distributions by that Restricted
Subsidiary of that Net Income is not at the date of determination permitted without any prior governmental approval (that has not been
obtained) or, directly or indirectly, by operation of the terms of its charter or any agreement (other than this Indenture, the Notes or its Guarantee), instrument, judgment, decree, order, statute,
rule or governmental regulation applicable to that Restricted Subsidiary or its stockholders, partners or members; 

        (4)   unrealized
losses and gains under derivative instruments included in the determination of Consolidated Net Income, including, without limitation, those resulting from
the application of Statement of Financial Accounting Standards No. 133, shall be excluded; and 

5

 

        (5)   the
cumulative effect of a change in accounting principles shall be excluded. 

        "Consolidated Net Tangible Assets" means, with respect to any Person at any date of determination, the aggregate amount of total assets
included in such Person's most recent quarterly or annual consolidated balance sheet prepared in accordance with GAAP less applicable reserves reflected in such balance sheet, after deducting the
following amounts: (1) all current liabilities reflected in such balance sheet, and (2) all goodwill, trademarks, patents, unamortized debt discounts and expenses and other like
intangibles reflected in such balance sheet. 

        "Continuing Directors" means, as of any date of determination, any member of the Board of Directors of the General Partner who
(1) was a member of such Board of Directors on the Issue Date or (2) was nominated for election or elected to such Board of Directors with the approval of a majority of the Continuing
Directors who were members of such Board at the time of such nomination or election. 

        "Corporate Trust Office of the Trustee" shall be at the address of the Trustee specified in Section 12.02 hereof or such other
address as to which the Trustee may give notice to the Issuers. 

        "Credit Agreement" means that certain Second Amended and Restated Credit Agreement, dated July 30, 2004, among the Operating
Company, the banks parties thereto and Royal Bank of Canada, as administrative agent, consisting of a revolver loan and a term loan facility, including any related notes, guarantees, collateral
documents, instruments and agreements executed in connection therewith, and in each case as amended, restated, modified, renewed, refunded, replaced or refinanced in whole or in part from time to
time. 

        "Credit Facilities" means, with respect to the Partnership, MarkWest Finance or any Restricted Subsidiary, one or more credit facilities
or commercial paper facilities, including the Credit Agreement,
providing for revolving credit loans, term loans, receivables financing (including through the sale of receivables to such lenders or to special purpose entities formed to borrow from such lenders
against such receivables) or letters of credit, in each case, as amended, restated, modified, renewed, refunded, replaced or refinanced in whole or in part from time to time. 

        "Default" means any event that is or with the passage of time or the giving of notice or both would be, an Event of Default. 

        "Depositary" means, with respect to the Notes issuable or issued in whole or in part in global form, the Person specified in
Section 2.03 hereof as the Depositary with respect to the Notes, and any and all successors thereto appointed as depositary hereunder and having become such pursuant to the applicable provision
of this Indenture. 

        "Disqualified Equity" means any Equity Interest that, by its terms (or by the terms of any security into which it is convertible, or for
which it is exchangeable, in each case at the option of the holder thereof), or upon the happening of any event, matures or is mandatorily redeemable, pursuant to a sinking fund obligation or
otherwise, or redeemable at the option of the holder thereof, in whole or in part, on or prior to the date that is 91 days after the date on which the Notes mature. Notwithstanding the
preceding sentence, any Equity Interest that would constitute Disqualified Equity solely because the holders thereof have the right to require the Partnership or any of its Restricted Subsidiaries to
repurchase such Equity Interests upon the occurrence of a change of control or an asset sale shall not constitute Disqualified Equity if the terms of such Equity Interests provide that the Partnership
or Restricted Subsidiary may not repurchase or redeem any such Equity Interests pursuant to such provisions unless such repurchase or redemption is conditioned upon, and subject to, compliance with
Section 4.08 hereof. 

        "Distribution Compliance Period" means the 40-day distribution compliance period as defined in Regulation S. 

6

 

        "Equity Interests" means: 

        (1)   in
the case of a corporation, corporate stock; 

        (2)   in
the case of an association or business entity, any and all shares, interests, participations, rights or other equivalents (however designated) of corporate stock; 

        (3)   in
the case of a partnership or limited liability company, partnership or membership interests (whether general or limited); 

        (4)   any
other interest or participation that confers on a Person the right to receive a share of the profits and losses of, or distributions of assets of, the issuing
Person; and 

        (5)   all
warrants, options or other rights to acquire any of the interests described in clauses (1) through (4) above (but excluding any debt security that is
convertible into, or exchangeable for, any of the interests described in clauses (1) through (4) above). 

        "Equity Offering" means any public or private sale for cash of Equity Interests of the Partnership (excluding sales made to any Restricted
Subsidiary and excluding sales of Disqualified Equity) after the Issue Date; provided that a private placement of Equity Interests will not be deemed an Equity Offering unless net cash proceeds of at
least $10.0 million are received. 

        "Euroclear" means the Euroclear System or any successor securities clearing agency. 

        "Exchange Act" means the Securities Exchange Act of 1934, as amended. 

        "Exchange Notes" means the 6.875% Series B Senior Notes due 2014, having terms substantially identical to the Series A
Notes, offered to the Holders of the Series A Notes under an Exchange Offer Registration Statement. 

        "Exchange Offer" means an offer that may be made by the Issuers pursuant to a Registration Rights Agreement to the Holders of the
Series A Notes to exchange their Series A Notes for a like aggregate principal amount of the Exchange Notes registered under the Securities Act. 

        "Exchange Offer Registration Statement" means a registration statement filed by the Issuers and the Subsidiary Guarantors with the SEC to
register the Exchange Notes for issuance in an Exchange Offer. 

        "Existing Indebtedness" means the aggregate principal amount of Indebtedness of the Partnership and its Restricted Subsidiaries in
existence on the Issue Date. 

        "Fixed Charge Coverage Ratio" means, with respect to any specified Person for any four-quarter reference period, the ratio of
the Consolidated Cash Flow of such Person for such period to the Fixed Charges of such Person for such period. In the event that the specified Person or any of its Restricted Subsidiaries incurs,
assumes, guarantees, repays or redeems any Indebtedness (other than revolving credit borrowings not constituting a permanent commitment reduction) or issues or redeems Disqualified Equity subsequent
to the commencement of the period for which the Fixed Charge Coverage Ratio is being calculated but prior to the date on which the event for which the calculation of the Fixed Charge Coverage Ratio is
made (the "Calculation Date"), then the Fixed Charge Coverage Ratio shall be calculated giving pro forma effect to such incurrence, assumption, guarantee, repayment or redemption of Indebtedness, or
such issuance or redemption of Disqualified Equity, and the application of the net proceeds thereof as if the same had occurred at the beginning of the applicable four-quarter reference
period (and if such Indebtedness is incurred to finance the acquisition of assets (including, without limitation, a single asset, a division or segment or an entire company) that were conducting
commercial operations prior to such acquisition, there shall be included pro forma net income for such assets, as if such assets had been acquired on the first day of such period). 

7

 

        In
addition, for purposes of calculating the Fixed Charge Coverage Ratio: 

        (1)   acquisitions
that have been made by the specified Person or any of its Restricted Subsidiaries, including through mergers or consolidations and including any related
financing transactions, during the four-quarter reference period or subsequent to such reference period and on or prior to the Calculation Date shall be deemed to have occurred on the
first day of the four-quarter reference period; 

        (2)   the
Consolidated Cash Flow attributable to discontinued operations, as determined in accordance with GAAP, and operations or businesses disposed of prior to the
Calculation Date, shall be excluded; 

        (3)   the
Fixed Charges attributable to discontinued operations, as determined in accordance with GAAP, and operations or businesses disposed of prior to the Calculation Date,
shall be excluded, but only to the extent that the obligations giving rise to such Fixed Charges will not be obligations of the specified Person or any of its Restricted Subsidiaries following the
Calculation Date; 

        (4)   interest
on outstanding Indebtedness of the specified Person or any of its Restricted Subsidiaries as of the last day of the four-quarter reference period
shall be deemed to have accrued at a fixed rate per annum equal to the rate of interest on such Indebtedness in effect on such last day after giving effect to any Hedging Obligation then in effect;
and 

        (5)   if
interest on any Indebtedness incurred by the specified Person or any of its Restricted Subsidiaries on such date may optionally be determined at an interest rate
based upon a factor of a prime or similar rate, a eurocurrency interbank offered rate or other rates, then the interest rate in effect on the last day of the four-quarter reference period
will be deemed to have been in effect during such period. 

        "Fixed Charges" means, with respect to any Person for any period, the sum, without duplication, of: 

        (1)   the
consolidated interest expense of such Person and its Restricted Subsidiaries for such period, whether paid or accrued, including, without limitation, amortization of
debt issuance costs and original issue discount, non-cash interest payments, the interest component of any deferred payment obligations, the interest component of all payments associated
with Capital Lease Obligations, imputed interest with respect to Attributable Debt, commissions, discounts, and other fees and charges incurred in respect of letter of credit or bankers' acceptance
financings, and net of the effect of all payments made or received pursuant to interest-rate Hedging Obligations; plus 

        (2)   the
consolidated interest expense of such Person and its Restricted Subsidiaries that was capitalized during such period; plus 

        (3)   any
interest expense on Indebtedness of another Person that is guaranteed by such Person or one of its Restricted Subsidiaries or secured by a Lien on assets of such
Person or one of its Restricted Subsidiaries, whether or not such guarantee or Lien is called upon; plus 

        (4)   the
product of (a) all dividend payments, whether paid or accrued and whether or not in cash, on any series of Disqualified Equity of such Person or any of its
Restricted Subsidiaries, other than dividend payments on Equity Interests payable solely in Equity Interests of the Partnership (other than Disqualified Equity) or to the Partnership or a Restricted
Subsidiary of the Partnership, times (b) a fraction, the numerator of which is one and the denominator of which is one minus the then current combined federal, state and local statutory tax
rate of such Person, expressed as a decimal; 

in
each case, on a consolidated basis and in accordance with GAAP. 

8

 

        "GAAP" means generally accepted accounting principles in the United States, which are in effect from time to time. 

        "General Partner" means MarkWest Energy GP, L.L.C., a Delaware limited liability company, and its successors and permitted assigns as
general partner of the Partnership. 

        "Global Note Legend" means the legend set forth in Section 2.06(g)(ii), which is required to be placed on all Global Notes
issued under this Indenture. 

        "Global Notes" means, individually and collectively, each of the Restricted Global Notes and the Unrestricted Global Notes, in the form of
Exhibit A hereto issued in accordance with Section 2.01, 2.06(b) or 2.06(f) hereof. 

        The
term "guarantee" means a guarantee, other than by endorsement of negotiable instruments for collection in the ordinary course of
business, direct or indirect, in any manner, including, without limitation, by way of a pledge of assets, or through letters of credit or reimbursement, "claw-back,"
"make-well," or "keep-well" agreements in respect thereof, of all or any part of any Indebtedness. The term "guarantee" used as a verb has a corresponding meaning. The term
"guarantor" shall mean any Person providing a guarantee of any obligation. 

        "Guarantee" means, individually and collectively, the guarantees given by the Subsidiary Guarantors pursuant to Article 10 hereof,
including a notation in the Notes substantially in the form attached hereto as Exhibit D. 

        "Guarantee Obligations" means, with respect to each Subsidiary Guarantor, the obligations of such Guarantor under Article 10. 

        "Guarantor Subordinated Obligation" means, with respect to a Subsidiary Guarantor, any Indebtedness or other Obligations of such
Subsidiary Guarantor (whether outstanding on the Issue Date or thereafter incurred) which are expressly subordinate in right of payment to the Obligations of such Subsidiary Guarantor under its
Guarantee pursuant to a written agreement. 

        "Hedging Obligations" means, with respect to any Person, the obligations of such Person under interest rate and commodity price swap
agreements, interest rate and commodity price cap agreements, interest rate and commodity price collar agreements and foreign currency and commodity price exchange agreements, options or futures
contracts or other similar agreements or arrangements or Hydrocarbon
hedge contracts or Hydrocarbon forward sales contracts, in each case designed to protect such Person against fluctuations in interest rates, foreign exchange rates, or commodities prices. 

        "Holder" means the Person in whose name a Note is registered on the Registrar's books. 

        "Hydrocarbons" means crude oil, natural gas, casinghead gas, drip gasoline, natural gasoline, condensate, distillate, liquid hydrocarbons,
gaseous hydrocarbons and all constituents, elements or compounds thereof and products refined or processed therefrom. 

        "IAI Global Note" means the Global Note in the form of Exhibit A hereto bearing the Global Note Legend and the
Private Placement Legend and that has the "Schedule of Exchange of Interests in the Global Note" attached thereto and deposited with and registered in the name of the Depositary or its nominee that
will be issued in a denomination equal to the outstanding principal amount of the Notes transferred to Institutional Accredited Investors in accordance with 2.06(b)(iii)(C), subject to adjustment as
provided in Section 2.06 hereof. 

        "Indebtedness" means, with respect to any specified Person, any indebtedness of such Person, whether or not contingent: 

        (1)   in
respect of borrowed money; 

9

 

        (2)   evidenced
by bonds, notes, debentures or similar instruments or letters of credit (or reimbursement agreements in respect thereof); 

        (3)   in
respect of banker's acceptances; 

        (4)   representing
Capital Lease Obligations; 

        (5)   representing
all Attributable Debt of such Person in respect of any sale and lease-back transactions not involving a Capital Lease Obligation; 

        (6)   representing
the balance deferred and unpaid of the purchase price of any property, except any such balance that constitutes an accrued expense or trade payable incurred
in the ordinary course of business; 

        (7)   representing
Disqualified Equity; or 

        (8)   representing
any Hedging Obligations; 

if
and to the extent any of the preceding items (other than letters of credit, Disqualified Equity and Hedging Obligations) would appear as a liability upon a balance sheet of the specified Person
prepared in accordance with GAAP. In addition, the term "Indebtedness" includes all Indebtedness of others secured by a Lien on any asset of the specified Person (whether or not such Indebtedness is
assumed by the specified Person) and, to the extent not otherwise included, the guarantee by such Person of any Indebtedness of any other Person, provided that a guarantee otherwise permitted by this
Indenture to be incurred by the Partnership or any of its Restricted Subsidiaries of Indebtedness incurred by the Partnership or a Restricted Subsidiary in compliance with the terms of this Indenture
shall not constitute a separate incurrence of Indebtedness. 

        The
amount of any Indebtedness outstanding as of any date shall be: 

        (1)   the
accreted value thereof, in the case of any Indebtedness issued with original issue discount; 

        (2)   in
the case of any Hedging Obligation, the termination value of the agreement or arrangement giving rise to such Hedging Obligation that would be payable by such Person
at such date; 

        (3)   in
the case of any letter of credit, the maximum potential liability thereunder; and 

        (4)   the
principal amount thereof, together with any interest thereon that is more than 30 days past due, in the case of any other Indebtedness. 

        For
purposes of clause (7) of the first paragraph of this definition, Disqualified Equity shall be valued at the maximum fixed redemption, repayment or repurchase price,
which shall be calculated in accordance with the terms of such Disqualified Equity as if such Disqualified Equity were repurchased on any date on which Indebtedness shall be required to be determined
pursuant to this Indenture; provided, however, that if such Disqualified Equity is not then permitted by its terms to be redeemed, repaid or
repurchased, the redemption, repayment or repurchase price shall be the book value of such Disqualified Equity. The amount of Indebtedness of any Person at any date shall be the outstanding balance at
such date of all unconditional Obligations as described above and the maximum liability of any guarantees at such date; provided that for purposes of calculating the amount of any
non-interest bearing or other discount security, such Indebtedness shall be deemed to be the principal amount thereof that would be shown on the balance sheet of the issuer thereof dated
such date prepared in accordance with GAAP, but that such security shall be deemed to have been incurred only on the date of the original issuance thereof. 

        "Indenture" means this Indenture, as amended or supplemented from time to time. 

10

 

        "Indirect Participant" means a Person who holds a beneficial interest in a Global Note through a Participant. 

        "Initial Purchasers" means J.P. Morgan Securities Inc., RBC Capital Markets Corporation, Fortis Securities LLC, Jefferies &
Company, Inc., Lehman Brothers Inc., Piper Jaffray & Co., SG Americas Securities, LLC and Wachovia Capital Markets, LLC. 

        "Institutional Accredited Investor" means an institution that is an "accredited investor" as defined in Rule 501(a)(1), (2),
(3) or (7) of the rules and regulations promulgated under the Securities Act. 

        "Interest Payment Date" means Stated Maturity of an installment of interest on the Notes. 

        "Investment Grade Rating" means a rating equal to or higher than Baa3 (or the equivalent) by Moody's and BBB- (or the
equivalent) by Standard & Poor's. 

        "Investments" means, with respect to any Person, all investments by such Person in other Persons (including Affiliates) in the forms of
direct or indirect loans (including guarantees of Indebtedness or other Obligations), advances (other than advances to customers in the ordinary course of business that are recorded as accounts
receivable on the balance sheet of the lender and commission, moving, travel and similar advances to officers and employees made in the ordinary course of business) or capital contributions, purchases
or other acquisitions for consideration of Indebtedness, Equity Interests or other securities, together with all items that are or would be classified as investments on a balance sheet prepared in
accordance with GAAP. For purposes of the definition of "Unrestricted Subsidiary," the definition of "Restricted Payment" and the covenant in Section 4.08 hereof, (1) the term
"Investment" shall include the portion (proportionate to the Partnership's Equity Interest in such Subsidiary) of the fair market value of the net assets of any Subsidiary of the Partnership or any of
its Restricted Subsidiaries at the time that such Subsidiary is designated an Unrestricted Subsidiary; provided, however, that upon a redesignation of such Subsidiary as a Restricted Subsidiary, the
Partnership or such Restricted Subsidiary shall be deemed to continue to have a permanent "Investment" in such Subsidiary at the time immediately before the effectiveness of such redesignation less
the portion (proportionate to the Partnership's or such Restricted Subsidiary's Equity Interest in such Subsidiary) of the fair market value of the net assets of such Subsidiary at the time of such
redesignation, and (2) any property transferred to or from an Unrestricted Subsidiary shall be valued at its fair market value at the time of such transfer, in each case as determined in good
faith by the Board of Directors of the General Partner. If the Partnership or any Restricted Subsidiary of the Partnership sells or otherwise disposes of any Equity Interests of any direct or indirect
Restricted Subsidiary of the Partnership such that, after giving effect to any such sale or disposition, such Person is no longer a Restricted Subsidiary of the Partnership, the Partnership shall be
deemed to have made an Investment on the date of any such sale or disposition equal to the fair market value of the Equity Interests of such Restricted Subsidiary not sold or disposed of in an amount
determined as provided in the last paragraph of Section 4.08(b) hereof. 

        "Issue Date" means October 25, 2004. 

        "Issuers" means the Partnership and MarkWest Finance, collectively; "Issuer" means the Partnership or MarkWest Finance. 

        "Joint Venture" means any Person that is not a direct or indirect Subsidiary of the Partnership in which the Partnership or any of its
Restricted Subsidiaries makes any Investment. 

        "Legal Holiday" means a Saturday, a Sunday or a day on which banking institutions in the City of Denver, Colorado or New York, New York or
at a place of payment are authorized by law, regulation or executive order to remain closed. If a payment date is a Legal Holiday at a place of payment, payment may be made at that place on the next
succeeding day that is not a Legal Holiday, and no interest shall accrue for the intervening period. 

11

   
        "Letter of Transmittal" means the letter of transmittal to be prepared by the Issuers and sent to all Holders of the Series A Notes
for use by such Holders in connection with an Exchange Offer. 

        "Lien" means, with respect to any asset, any mortgage, lien (statutory or otherwise), pledge, charge, security interest, hypothecation,
assignment for security, claim, preference, priority or encumbrance of any kind in respect of such asset, whether or not filed, recorded or otherwise perfected under applicable law, including any
conditional sale or other title retention agreement or any lease in the nature thereof, any option or other agreement to grant a security interest in and any filing of or agreement to give any
financing statement under the Uniform Commercial Code (or equivalent statute) of any jurisdiction other than a precautionary financing statement respecting a lease not intended as a security
agreement. 

        "Make Whole Amount" means, with respect to any Note at any redemption date, the excess, if any, of (1) an amount equal to
the present value of (a) the redemption price of such Note at November 1, 2009 plus (b) the remaining scheduled interest payments on the Notes to be redeemed (subject to
the right of Holders on the relevant record date to receive interest due on the relevant Interest Payment Date) to November 1, 2009 (other than interest accrued to the redemption date),
computed using a discount rate equal to the Treasury Rate plus 50 basis points, over (2) the aggregate principal amount of the Notes to be redeemed. 

        "MarkWest Finance" means the Person named as such in the preamble of this Indenture under and until a successor replaces it pursuant to
the applicable provision of this Indenture and thereafter means such successor. 

        "MarkWest Hydrocarbon" means MarkWest Hydrocarbon, Inc., a Delaware corporation, and its successors. 

        "MarkWest Hydrocarbon Group" means, collectively, (1) John M. Fox and any of his Affiliates, (2) MarkWest Hydrocarbon and
(3) each Person which is a direct or indirect Subsidiary of MarkWest Hydrocarbon. 

        "Moody's" means Moody's Investors Service, Inc. or any successor to the rating agency business thereof. 

        "Net Income" means, with respect to any Person, the consolidated net income (loss) of such Person and its Restricted Subsidiaries,
determined in accordance with GAAP and before any reduction in respect of preferred stock dividends, excluding, however: 

        (1)   the
aggregate gain (but not loss in excess of such aggregate gain), together with any related provision for taxes on such gain, realized in connection with: 

	(a)
	any
Asset Sale; or

	(b)
	the
disposition of any securities by such Person or any of its Restricted Subsidiaries or the extinguishment of any Indebtedness of such Person or any of its Restricted Subsidiaries;
and 

        (2)   any
extraordinary gain (but not loss), together with any related provision for taxes on such extraordinary gain (but not loss). 

        "Net Proceeds" means, with respect to any Asset Sale or sale of Equity Interests, the aggregate proceeds received by the Partnership or
any of its Restricted Subsidiaries in cash or Cash Equivalents in respect of any Asset Sale or sale of Equity Interests (including, without limitation, any cash received upon the sale or other
disposition of any non-cash consideration received in any such sale), net of, without duplication, (1) the direct costs relating to such Asset Sale or sale of Equity Interests,
including, without limitation, brokerage commissions and legal, accounting and investment banking fees, sales commissions, recording fees, title transfer fees and any relocation expenses incurred as a
result 

12

 

thereof,
(2) taxes paid or payable as a result thereof, in each case after taking into account any available tax credits or deductions and any tax sharing arrangements and amounts required to
be applied to the repayment of Indebtedness secured by a Lien on the asset or Equity Interests that were the subject of such Asset Sale or sale of Equity Interests, (3) all distributions and
payments required to be made to minority interest holders in Restricted Subsidiaries as a result of such Asset Sale and (4) any amounts to be set aside in any reserve established in accordance
with GAAP or any amount placed in escrow, in either case for adjustment in respect of the sale price of such asset or Equity Interests or for liabilities associated with such Asset Sale or sale of
Equity Interests and retained by the Partnership or any of its Restricted Subsidiaries until such time as such reserve is reversed or such escrow arrangement is terminated, in which case Net Proceeds
shall include only the amount of the reserve so reversed or the amount returned to the Partnership or its Restricted Subsidiaries from such escrow arrangement, as the case may be. 

        "Non-Recourse Debt" means Indebtedness as to which: 

        (1)   neither
the Partnership nor any of its Restricted Subsidiaries (a) provides credit support of any kind (including any undertaking, agreement or instrument that
would constitute Indebtedness), (b) is directly or indirectly liable as a guarantor or otherwise, or (c) constitutes the lender of such Indebtedness; 

        (2)   no
default with respect to which (including any rights that the holders thereof may have to take enforcement action against an Unrestricted Subsidiary) would permit upon
notice, lapse of time or both any holder of any other Indebtedness (other than the Notes) of the Partnership or any of its Restricted Subsidiaries to declare a default on such other Indebtedness or
cause the payment thereof to be accelerated or payable prior to its Stated Maturity; and 

        (3)   the
lenders have been notified in writing that they will not have any recourse to the stock or assets of the Partnership or any of its Restricted Subsidiaries. 

        "Non-U.S. Person" means a person who is not a U.S. Person. 

        "Note Custodian" means the Trustee, as custodian with respect to the Notes in global form, or any successor entity thereto. 

        "Notes" has the meaning assigned to it in the preamble to this Indenture. 

        "Obligations" means any principal, interest, penalties, fees, indemnifications, reimbursement obligations, damages and other liabilities
payable under the documentation governing any Indebtedness. 

        "Offering" means the offering of the Series A Notes by the Issuers pursuant to the Offering Memorandum. 

        "Offering Memorandum" means the offering memorandum of the Issuers dated October 19, 2004 relating to the Offering. 

        "Officer" means, with respect to any Person, the Chairman of the Board, the Chief Executive Officer, the President, the Chief Operating
Officer, the Chief Financial Officer, the Chief Accounting Officer, the Treasurer, any Assistant Treasurer, the Controller, the Secretary or any Vice-President of such Person (or, with
respect to the Partnership, so long as it remains a partnership, the General Partner). 

        "Officers' Certificate" means a certificate signed on behalf of each of the Partnership and MarkWest Finance by two of its Officers, one
of whom must be the principal executive officer, the principal financial officer or the principal accounting officer of such Person, that meets the requirements of Section 12.05 hereof. 

13

 

        "Operating Company" means MarkWest Energy Operating Company, L.L.C., a Delaware limited liability company, and its successors. 

        "Operating Surplus" shall have the meaning assigned to such term in the Partnership Agreement, as in effect on the Issue Date. 

        "Opinion of Counsel" means an opinion from legal counsel who is reasonably acceptable to the Trustee, that meets the requirements of
Section 12.05 hereof. The counsel may be an employee of or counsel to the Partnership, MarkWest Finance or the General Partner (or any Subsidiary Guarantor, if applicable), any Subsidiary of
the Partnership or the Trustee. 

        "Participant" means, with respect to DTC, Euroclear or Clearstream, a Person who has an account with DTC, Euroclear or Clearstream,
respectively (and, with respect to DTC, shall include Euroclear and Clearstream). 

        "Participating Broker-Dealer" has the meaning set forth in the Registration Rights Agreement relating to the Series A Notes issued
on the Issue Date. 

        "Partnership" means the Person named as such in the preamble of this Indenture unless and until a successor replaces it pursuant to the
applicable provisions of this Indenture and thereafter means such successor. 

        "Partnership Agreement" means the Amended and Restated Agreement of Limited Partnership of MarkWest Energy Partners, L.P., dated as of
May 24, 2002, as such may be amended, modified or supplemented from time to time. 

        "Permitted Business" means either (1) gathering, transporting, treating, processing, marketing or otherwise handling Hydrocarbons,
or activities or services reasonably related or ancillary thereto including entering into Hedging Obligations to support these businesses, or (2) any other business that generates gross income
that constitutes "qualifying income" under Section 7704(d) of the Code. 

        "Permitted Business Investments" means Investments by the Partnership or any of its Restricted Subsidiaries in any Unrestricted Subsidiary
of the Partnership or in any Joint Venture, provided that: 

        (1)   either
(a) at the time of such Investment and immediately thereafter, the Partnership could incur $1.00 of additional Indebtedness under
Section 4.09(a) or (b) such investment is made with the proceeds of Incremental Funds; 

        (2)   if
such Unrestricted Subsidiary or Joint Venture has outstanding Indebtedness at the time of such Investment, either (a) all such Indebtedness is
Non-Recourse Debt with respect to the Partnership and its Restricted Subsidiaries or (b) any such Indebtedness of such Unrestricted Subsidiary or Joint Venture that is recourse to
the Partnership or any of its Restricted Subsidiaries (which shall include all Indebtedness of such Unrestricted Subsidiary or Joint Venture for which the Partnership or any of its Restricted
Subsidiaries may be directly or indirectly, contingently or otherwise, obligated to pay, whether pursuant to the terms of such Indebtedness, by law or pursuant to any guaranty or
"claw-back," "make-well" or "keep-well" arrangement) could, at the time such Investment is made and, if later, at the time any such Indebtedness is incurred, be
incurred by the Partnership and its Restricted Subsidiaries in accordance with the limitation on Indebtedness set forth in Section 4.09(a); and 

        (3)   such
Unrestricted Subsidiary's or Joint Venture's activities are not outside the scope of the Permitted Business. 

        "Permitted Investments" means: 

        (4)   any
Investment in, or that results in the creation of, any Restricted Subsidiary of the Partnership; 

14

 

        (5)   any
Investment in the Partnership or in a Restricted Subsidiary of the Partnership (excluding redemptions, purchases, acquisitions or other retirements of Equity
Interests in the Partnership); 

        (6)   any
Investment in cash or Cash Equivalents; 

        (7)   any
Investment by the Partnership or any Restricted Subsidiary of the Partnership in a Person if as a result of such Investment: 

	(a)
	such
Person becomes a Restricted Subsidiary of the Partnership; or

	(b)
	such
Person is merged, consolidated or amalgamated with or into, or transfers or conveys substantially all of its assets to, or is liquidated into, the Partnership or a Restricted
Subsidiary of the Partnership; 

        (8)   any
Investment made as a result of the receipt of consideration consisting of other than cash or Cash Equivalents from an Asset Sale that was made pursuant to and in
compliance with Section 4.07; 

        (9)   any
Investment in a Person solely in exchange for the issuance of Equity Interests (other than Disqualified Equity) of the Partnership; 

        (10) Investments
in stock, obligations or securities received in settlement of debts owing to the Partnership or any of its Restricted Subsidiaries as a result of bankruptcy
or insolvency proceedings or upon the foreclosure, perfection or enforcement of any Lien in favor of the Partnership or any such Restricted Subsidiary, in each case as to debt owing to the Partnership
or any such Restricted Subsidiary that arose in the ordinary course of business of the Partnership or any such Restricted Subsidiary; 

        (11) any
Investment in Hedging Obligations permitted to be incurred under Section 4.09 hereof; and 

        (12) other
Investments in any Person engaged in a Permitted Business (other than an Investment in an Unrestricted Subsidiary) having an aggregate fair market value (measured
on the date each such Investment was made and without giving effect to subsequent changes in value), when taken together
with all other Investments made pursuant to this clause (9) since the Issue Date and existing at the time of the Investment, which is the subject of the determination, was made, not to
exceed the greater of (a) $10.0 million and (b) 2.50% of Consolidated Net Tangible Assets. 

        "Permitted Liens" means: 

        (1)   Liens
securing Indebtedness under the Credit Facilities permitted to be incurred under this Indenture provided that all such Liens are pari
passuwith each other; 

        (2)   Liens
in favor of the Partnership or any of its Restricted Subsidiaries; 

        (3)   any
interest or title of a lessor in the property subject to a Capital Lease Obligation; 

        (4)   Liens
on property of a Person existing at the time such Person is merged with or into or consolidated with the Partnership or any Restricted Subsidiary of the
Partnership, provided that such Liens were in existence prior to, and were not obtained in contemplation of, such merger or consolidation and do not extend to any assets other than those of the Person
merged into or consolidated with the Partnership or such Restricted Subsidiary; 

        (5)   Liens
on property existing at the time of acquisition thereof by the Partnership or any Restricted Subsidiary of the Partnership, provided that such Liens were in
existence prior to, and 

15

 

were
not obtained in contemplation of, such acquisition and relate solely to such property, accessions thereto and the proceeds thereof; 

        (6)   Liens
to secure the performance of tenders, bids, leases, statutory obligations, surety or appeal bonds, government contracts, performance bonds or other obligations of
a like nature incurred in the ordinary course of business; 

        (7)   Liens
on any property or asset acquired, constructed or improved by the Partnership or any Restricted Subsidiary, which (a) are in favor of the seller of such
property or assets, in favor of the Person constructing or improving such asset or property, or in favor of the Person that provided the funding for the acquisition, construction or improvement of
such asset or property, (b) are created within 360 days after the date of acquisition, construction or improvement, (c) secure the purchase price
or construction or improvement cost, as the case may be, of such asset or property in an amount not to exceed the lesser of (i) the cost to the Partnership and its Restricted Subsidiaries of
such acquisition, construction or improvement of such asset or property and (ii) 100% of the fair market value (as determined by the Board of Directors of the General Partner) of such
acquisition, construction or improvement of such asset or property, and (d) are limited to the asset or property so acquired, constructed or improved (including proceeds thereof, accessions
thereto and upgrades thereof); 

        (8)   Liens
to secure performance of Hedging Obligations of the Partnership or any Restricted Subsidiary; 

        (9)   Liens
existing on the Issue Date and Liens in connection with any extensions, refinancing, renewal, replacement or defeasance of any Indebtedness or other obligation
secured thereby, provided that (a) the principal amount of the Indebtedness secured by such Lien is not increased and (b) no assets are encumbered by any such Lien other than the assets
permitted to be encumbered immediately prior to such extension, refinancing, renewal, replacement or defeasance; 

        (10) Liens
on pipelines or pipeline facilities that arise by operation of law; 

        (11) Liens
arising under operating agreements, joint venture agreements, partnership agreements, oil and gas leases, farmout agreements, division orders, contracts for sale,
transportation or exchange of oil and natural gas, unitization and pooling declarations and agreements, area of mutual interest agreements and other agreements arising in the ordinary course of the
Partnership's or any Restricted Subsidiary's business that are customary in the Permitted Business; 

        (12) Liens
securing the Obligations of the Issuers under the Notes and this Indenture and of the Subsidiary Guarantors under the Guarantees; 

        (13) Liens
upon specific items of inventory or other goods and proceeds of any Person securing such Person's Obligations in respect of bankers' acceptances issued or created
for the account of such Person to facilitate the purchase, shipment or storage of such inventory or other goods and permitted by Section 4.09 hereof; 

        (14) Liens
securing any Indebtedness equally and ratably with all Obligations due under the Notes or any Guarantee pursuant to a contractual covenant that limits liens in a
manner substantially similar to Section 4.10 hereof; and 

        (15) Liens
incurred in the ordinary course of business of the Partnership or any Restricted Subsidiary of the Partnership with respect to Obligations that do not exceed 10%
of Consolidated Net Tangible Assets at any one time outstanding. 

After
the first suspension of the covenants pursuant to Section 4.19 hereof, for purposes of complying with Section 4.10, the Liens described in clauses (1) and (15) of
this definition of "Permitted Liens" 

16

 

shall
be Permitted Liens only to the extent those Liens secure Indebtedness not exceeding, at the time of determination, 10% of the Consolidated Net Tangible Assets of the Partnership. Once effective,
this 10% limitation on Permitted Liens will continue to apply during any later period in which the Notes do not have an Investment Grade Rating from both Rating Agencies. 

        "Permitted Refinancing Indebtedness" means any Indebtedness of the Partnership or any of its Restricted Subsidiaries issued in exchange
for, or the net proceeds of which are used to extend, refinance, renew, replace, defease or refund other Indebtedness of the Partnership or any of its Restricted Subsidiaries (other than intercompany
Indebtedness); provided that: 

        (1)   the
principal amount of such Permitted Refinancing Indebtedness does not exceed the principal amount of, plus accrued interest on the Indebtedness so extended,
refinanced, renewed, replaced, defeased or refunded (plus the amount of necessary fees and expenses incurred in connection therewith and any premiums paid on the Indebtedness so extended, refinanced,
renewed, replaced, defeased or refunded); 

        (2)   such
Permitted Refinancing Indebtedness has a final maturity date no earlier than the final maturity date of, and has a Weighted Average Life to Maturity equal to or
greater than the Weighted Average Life to Maturity of, the Indebtedness being extended, refinanced, renewed, replaced, defeased or refunded; 

        (3)   if
the Indebtedness being extended, refinanced, renewed, replaced, defeased or refunded is subordinated in right of payment to the Notes or the Guarantees, such
Permitted Refinancing Indebtedness is subordinated in right of payment to, the Notes or the Guarantees, as the case may be, on terms at least as favorable to the Holders of Notes as those contained in
the documentation governing the Indebtedness being extended, refinanced, renewed, replaced, defeased or refunded; and 

        (4)   such
Indebtedness is not incurred by a Restricted Subsidiary if the Partnership is the obligor on the Indebtedness being extended, refinanced, renewed, replaced,
defeased or refunded. 

        "Person" means any individual, corporation, partnership, joint venture, association, joint-stock company, trust, unincorporated
organization, limited liability company or government or agency or political subdivision thereof or other entity. 

        "Private Placement Legend" means the legend set forth in Section 2.06(g)(i) to be placed on all Notes issued under this
Indenture except where otherwise permitted by the provisions of this Indenture. 

        "QIB" means a "qualified institutional buyer" as defined in Rule 144A. 

        "Rating Agency" means each of Standard & Poor's and Moody's, or if Standard & Poor's or Moody's or both shall not make a
rating on the Notes publicly available, a nationally recognized statistical rating agency or agencies, as the case may be, selected by the Issuers (as certified by a resolution of the Board of
Directors of the General Partner) which shall be substituted for Standard & Poor's or Moody's, or both, as the case may be. 

        "Registrable Securities" has the meaning set forth in the Registration Rights Agreement applicable to such Notes. 

        "Registration Rights Agreement" means (1) with respect to the Series A Notes issued on the Issue Date that certain agreement
among the Issuers, the Subsidiary Guarantors and the Initial Purchasers requiring the Issuers and the Subsidiary Guarantors to file an Exchange Offer Registration Statement and a Shelf Registration
Statement, a form of which is attached to this Indenture as Annex B hereto, and (2) any other registration rights agreement relating to any additional Notes issued by the Issuers after the
Issue Date pursuant to Section 2.02. 

17

 

        "Regulation S" means Regulation S promulgated by the SEC under the Securities Act. 

        "Regulation S Global Note" means a Global Note in the form of Exhibit A hereto bearing the Global Note Legend
and the Private Placement Legend and that has the "Schedule of Exchange of Interests in the Global Note" attached thereto and deposited with or on behalf of and registered in the name of the
Depositary or its nominee, issued in a denomination equal to the outstanding principal amount of the Notes initially sold in reliance on Rule 903 of Regulation S, subject to adjustment
as provided in Section 2.06 hereof. 

        "Responsible Officer," when used with respect to the Trustee, means the officer in the Corporate Trust Department of the Trustee having
direct responsibility for administration of this Indenture. 

        "Restricted Certificated Note" means a Certificated Note bearing the Private Placement Legend. 

        "Restricted Global Note" means a Global Note bearing the Private Placement Legend and that bears the Global Note Legend and
that has the "Schedule of Exchanges of Interests in the Global Note" attached thereto. 

        "Restricted Investment" means an Investment other than a Permitted Investment or a Permitted Business Investment. 

        "Restricted Subsidiary" of a Person means any Subsidiary of the referenced Person that is not an Unrestricted Subsidiary. Notwithstanding
anything in this Indenture to the contrary, each of MarkWest Finance and the Operating Company shall be a Restricted Subsidiary of the Partnership. 

        "Rule 144" means Rule 144 promulgated by the SEC under the Securities Act. 

        "Rule 144A" means Rule 144A promulgated by the SEC under the Securities Act. 

        "Rule 903" means Rule 903 of Regulation S promulgated by the SEC under the Securities Act. 

        "Rule 904" means Rule 904 of Regulation S promulgated by the SEC under the Securities Act. 

        "SEC" means the Securities and Exchange Commission. 

        "Securities Act" means the Securities Act of 1933, as amended. 

        "Series A Notes" has the meaning set forth in the preamble of this Indenture. 

        "Shelf Registration Statement" means a shelf registration statement filed with the SEC by the Issuers and the Subsidiary Guarantors in
accordance with the applicable Registration Rights Agreement to register resales of the Series A Notes or the Exchange Notes. 

        "Significant Subsidiary" means any Subsidiary that would be a "significant subsidiary" as defined in Article 1,
Rule 1-02 of Regulation S-X, promulgated pursuant to the Securities Act and the Exchange Act, as such Regulation is in effect on the Issue Date. 

        "Standard & Poor's" means Standard & Poor's Ratings Services, a division of The McGraw-Hill
Companies, Inc., or any successor to the rating agency business thereof. 

        "Stated Maturity" means, with respect to any installment of interest or principal on any series of Indebtedness, the date on which such
payment of interest or principal was scheduled to be paid in the original documentation governing such Indebtedness, and shall not include any contingent Obligations to repay, redeem or repurchase any
such interest or principal prior to the date originally scheduled for the payment thereof. 

        "Subordinated Obligation" means any Indebtedness of the Partnership or MarkWest Finance (whether outstanding on the Issue Date or
thereafter incurred) which is subordinate or junior in right of payment to the Notes pursuant to a written agreement. 

18

 

        "Subsidiary" means, with respect to any Person: 

        (1)   any
corporation, association or other business entity (other than an entity referred to in clause (2) below) of which more than 50% of the total Voting
Stock is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of that Person (or a combination thereof); and 

        (2)   any
partnership (whether general or limited), limited liability company or joint venture (a) the sole general partner or the managing general partner or managing
member of which is such Person or a Subsidiary of such Person, or (b) if there are more than a single general partner or member, either (i) the only general partners or managing members
of which are such Person and/or one or more Subsidiaries of such Person (or any combination thereof) or (ii) such Person owns or controls, directly
or indirectly, a majority of the outstanding general partner interests, member interests or other Voting Stock of such partnership, limited liability company or joint venture, respectively. 

        "Subsidiary Guarantors" means each of: 

        (1)   MarkWest
Energy Operating Company, L.L.C., Basin Pipeline L.L.C., West Shore Processing Company, L.L.C., MarkWest Energy Appalachia, L.L.C., MarkWest Texas GP, L.L.C.,
MW Texas Limited, L.L.C., MarkWest Michigan Pipeline Company, L.L.C., MarkWest Western Oklahoma Gas Company, L.L.C., MarkWest Power Tex L.P., MarkWest Pinnacle L.P., MarkWest PNG Utility L.P.,
MarkWest Texas PNG Utility L.P., MarkWest Blackhawk L.P., MarkWest New Mexico L.P. and MarkWest Energy East Texas Gas Company L.P.; and 

        (2)   any
other Subsidiary of the Partnership that becomes a Subsidiary Guarantor in accordance with the provisions of Section 4.13 and Article 10 of this
Indenture; and 

        (3)   their
respective successors and assigns; 

in
each case until such Subsidiary Guarantor ceases to be such in accordance with this Indenture. Notwithstanding anything in this Indenture to the contrary, MarkWest Finance shall not be a Subsidiary
Guarantor. 

        "Tax Payment" means any payment of foreign, federal, state or local tax liabilities. 

        "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. Sections 77aaa-77bbbb) as in effect on the date on which this
Indenture is qualified under the TIA, except as provided in Section 9.03 hereof. 

        "Treasury Rate" means, at the time of computation, the yield to maturity of United States Treasury securities with a constant maturity (as
compiled and published in the most recent Federal Reserve Statistical Release H.15(519) which has become publicly available at least two Business Days prior to the redemption date or, if such
Statistical Release is no longer published, any publicly available source of similar market data) most nearly equal to the period from the redemption date to November 1, 2009;  provided, however,
that if such period is not equal to the constant maturity of a United States Treasury security for which a weekly average yield is
given, the Treasury Rate shall be obtained by linear interpolation (calculated to the nearest one-twelfth of a year) from the weekly average yields of United States Treasury securities for
which such yields are given, except that if the period from the redemption date to November 1, 2009 is less than one year, the weekly average yield on actually traded United States Treasury
securities adjusted to a constant maturity of one year shall be used. The Treasury Rate shall be calculated on the third Business Day preceding the redemption date. Any weekly average yields
calculated by interpolation shall be rounded to the nearest 1/100th of 1%, with any figure of 1/200th of 1% or above being rounded upward. 

19

 

        "Trustee" means the party named as such in the preamble of this Indenture until a successor replaces it in accordance with the applicable
provisions of this Indenture and thereafter means the successor serving hereunder. 

        "U.S. Government Obligations" means securities that are (1) direct Obligations of the United States of America for the payment of
which its full faith and credit is pledged; (2) Obligations of a Person controlled or supervised by and acting as an agency or instrumentality of the United States of America the payment of
which is unconditionally guaranteed as a full faith and credit obligation by the United States of America, which, in either case under clauses (1) or (2) above, are not callable or
redeemable at the option of the issuers thereof; or (3) depository receipts issued by a bank or trust company as custodian with respect to any such U.S. Government Obligations or a specific
payment of interest on or principal of any such U.S. Government Obligation held by such custodian for the account of the holder of a depository receipt, provided that (except as required by law) such
custodian is not authorized to make any deduction from the amount payable to the holder of such depository receipt from any amount received by the custodian in respect of the U.S. Government
Obligation evidenced by such depository receipt. 

        "U.S. Person" means a U.S. person as defined in Rule 902(k) of Regulation S promulgated by the SEC under the
Securities Act. 

        "Unrestricted Certificated Note" means one or more Certificated Notes that do not bear and are not required to bear the Private Placement
Legend. 

        "Unrestricted Global Note" means a permanent Global Note in the form of Exhibit A attached hereto that bears the Global
Note Legend and that has the "Schedule of Exchanges of Interests in the Global Note" attached thereto, and that is deposited with or on behalf of and registered in the name of the Depositary,
representing a series of Notes that do not bear the Private Placement Legend. 

        "Unrestricted Subsidiary" means any Subsidiary of the Partnership (other than MarkWest Finance or the Operating Company) that is
designated by the Board of Directors of the General Partner as an Unrestricted Subsidiary pursuant to a Board Resolution, but only to the extent that such Subsidiary: (1) has no Indebtedness
other than Non-Recourse Debt; (2) is not a party to any agreement, contract, arrangement or understanding with the Partnership or any Restricted Subsidiary of the Partnership unless
the terms of any such arrangement, contract, arrangement or understanding are no less favorable to the Partnership or such Restricted Subsidiary than those that might be obtained at the time from
Persons who are not Affiliates of the Partnership; (3) is a Person with respect to which neither the Partnership nor any of its Restricted Subsidiaries has any direct or indirect obligation
(a) to subscribe for additional Equity Interests or (b) to maintain or preserve such Person's financial condition or to cause such Person to achieve any specified levels of operating
results; and (4) has not guaranteed or otherwise directly or indirectly provided credit support for any Indebtedness of the Partnership or any of its Restricted Subsidiaries. Notwithstanding
anything in this Indenture to the contrary, neither MarkWest Finance nor the Operating Company shall be designated as an Unrestricted Subsidiary. 

        Any
designation of a Subsidiary of the Partnership as an Unrestricted Subsidiary shall be evidenced to the Trustee by filing with the Trustee a Board Resolution of the General Partner
giving effect to such designation and an Officers' Certificate certifying that such designation complied with the preceding conditions and was permitted by Section 4.08 hereof. If, at any time,
any Unrestricted Subsidiary would fail to meet the preceding requirements as an Unrestricted Subsidiary, it shall thereafter cease to be an Unrestricted Subsidiary for purposes of this Indenture and
any Indebtedness of such Subsidiary shall be deemed to be incurred by a Restricted Subsidiary of the Partnership as of such date and, if such Indebtedness is not permitted to be incurred as of such
date under Section 4.09 hereof, the Partnership shall be in default of such covenant. 

20

 

        "Voting Stock" of any Person as of any date means the Equity Interests of such Person pursuant to which the holders thereof have the
general voting power under ordinary circumstances to elect at least a majority of the board of directors, managers, general partners or trustees of such Person (regardless of whether, at the time,
Equity Interests of any other class or classes shall have, or might have, voting power by reason of the occurrence of any contingency) or, with respect to a partnership (whether general or limited),
any general partner interest in such partnership. 

        "Weighted Average Life to Maturity" means, when applied to any Indebtedness at any date, the number of years obtained by dividing:
(1) the sum of the products obtained by multiplying (a) the amount of each then remaining installment, sinking fund, serial maturity or other required payments of principal,
including payment at final maturity, in respect thereof, by (b) the number of years (calculated to the nearest one-twelfth) that will elapse between such date and the making
of such payment; by (2) the then outstanding principal amount of such Indebtedness. 

Section 1.02.
Other Definitions. 

	Term
 
	 	Defined in Section

	"Affiliate Transaction"	 	4.12
	"Asset Sale Offer"	 	3.09
	"Calculation Date"	 	1.01 (definition of Fixed Charge Coverage Ratio)
	"Change of Control Offer"	 	4.06(a)
	"Change of Control Payment"	 	4.06(a)
	"Change of Control Payment Date"	 	4.06(b)
	"Covenant Defeasance"	 	8.03
	"DTC"	 	2.03
	"Event of Default"	 	6.01
	"Excess Proceeds"	 	4.07(c)
	"Incremental Funds"	 	4.08(a)
	"incur"	 	4.09(a)
	"Legal Defeasance"	 	8.02
	"Offer Amount"	 	3.09
	"Offer Period"	 	3.09
	"Paying Agent"	 	2.03
	"Payment Default"	 	6.01(f)
	"Permitted Debt"	 	4.09(b)
	"Purchase Date"	 	3.09
	"Registrar"	 	2.03
	"Reinstatement Date"	 	4.19
	"Restricted Payments"	 	4.08(a)
	"Suspended Covenants"	 	4.19

Section 1.03.
Incorporation by Reference of Trust Indenture Act. 

        Whenever
this Indenture refers to a provision of the TIA, the provision is incorporated by reference in and made a part of this Indenture. 

        The
following TIA terms used in this Indenture have the following meanings: 

        "indenture
securities" means the Notes and the Guarantees; 

        "indenture
security holder" means a Holder of a Note; 

        "indenture
to be qualified" means this Indenture; 

21

 

        "indenture
trustee" or "institutional trustee" means the Trustee; 

        "obligor"
on the Notes means the Partnership, MarkWest Finance or any Subsidiary Guarantor and any successor obligor upon the Notes. 

        All
other terms used in this Indenture that are defined by the TIA, defined by TIA reference to another statute or defined by SEC rule under the TIA have the meanings so assigned to
them. 

Section 1.04.
Rules of Construction. 

        Unless
the context otherwise requires: 

        (1)   a
term has the meaning assigned to it; 

        (2)   an
accounting term not otherwise defined has the meaning assigned to it in accordance with GAAP; 

        (3)   "or"
is not exclusive; 

        (4)   words
in the singular include the plural, and in the plural include the singular; 

        (5)   provisions
apply to successive events and transactions; and 

        (6)   references
to sections of or rules under the Securities Act or the Exchange Act shall be deemed to include substitute, replacement of successor sections or
rules adopted by the SEC from time to time. 

ARTICLE 2

THE NOTES  

Section 2.01.
Form and Dating. 

        The
Notes and the Trustee's certificate of authentication shall be substantially in the form of Exhibit A hereto. The notation on each Note relating to the Guarantees shall
be substantially in the form set forth on Exhibit D, which is a part of this Indenture. The Notes may have notations, legends or endorsements required by law, stock exchange rule or usage. Each
Note shall be dated the date of its authentication. The Notes shall be in denominations of $1,000 and integral multiples thereof. 

        The
terms and provisions contained in the Notes (including the Guarantees) shall constitute, and are hereby expressly made, a part of this Indenture and the Partnership, MarkWest
Finance, the Subsidiary Guarantors, and the Trustee, by their execution and delivery of this Indenture, expressly agree to such terms and provisions and to be bound thereby. However, to the extent
permitted by law, if any provision of any Note conflicts with the express provisions of this Indenture, the provisions of this Indenture shall govern and be controlling. 

        Notes
issued in global form shall be substantially in the form of Exhibit A attached hereto (including the Global Note Legend and the "Schedule of Exchanges in the Global
Note" attached thereto). Notes issued in definitive form shall be substantially in the form of Exhibit A attached hereto (but without the Global Note Legend, the phrase identified in
footnote 3 thereto and without the "Schedule of Exchanges of Interests in the Global Note" attached thereto). Each Global Note shall represent such of the outstanding Notes as shall be
specified therein and each shall provide that it shall represent the aggregate principal amount of outstanding Notes from time to time endorsed thereon and that the aggregate principal amount of
outstanding Notes represented thereby may from time to time be reduced or increased, as appropriate, to reflect exchanges and redemptions. Any endorsement of a Global Note to reflect the amount
of any increase or decrease in the aggregate principal amount of outstanding Notes represented thereby shall be made by the Trustee or the Note Custodian, at the direction of the Trustee, in
accordance with instructions given by the Holder thereof as required by Section 2.06 hereof. 

22

 

Section 2.02.
Execution and Authentication. 

        One
Officer of the Partnership and one Officer of MarkWest Finance shall sign the Notes for the Partnership and MarkWest Finance, respectively, by manual or facsimile signature. 

        If
an Officer whose signature is on a Note no longer holds that office at the time a Note is authenticated, the Note shall nevertheless be valid. 

        A
Note shall not be valid until authenticated by the manual signature of the Trustee. The signature shall be conclusive evidence that the Note has been authenticated under
this Indenture. 

        The
Trustee shall, upon a written order of the Partnership and MarkWest Finance signed by one Officer of the Partnership and one Officer of MarkWest Finance, authenticate
(i) $225,000,000 aggregate principal amount of Notes, with the Guarantees endorsed thereon, for original issue on the Issue Date and (ii) from time to time thereafter any amount of
additional Notes specified by the Issuers, in each case, upon a written order of the Partnership and MarkWest Finance signed by one Officer of the Partnership and one Officer of MarkWest Finance. Such
order shall specify (a) the amount of the Notes of each series to be authenticated and the date of original issue thereof, and (b) whether the Notes are Series A Notes or Exchange
Notes. The aggregate principal amount of Notes of either series outstanding at any time may not exceed the aggregate principal amount of Notes of such series authorized for issuance by the Issuers
pursuant to one or more written orders of the Issuers, except as provided in Section 2.07 hereof. Subject to the foregoing, the aggregate principal amount of Notes of either series that may be
issued under this Indenture shall not be limited. 

        The
Series A Notes issued on the Issue Date and any additional Series A Notes subsequently issued, together with the Exchange Notes issued in exchange therefor, shall be
treated as a single class for all purposes under this Indenture, including, without limitation, waivers, amendments, redemptions and offers to purchase. 

        The
Trustee may appoint an authenticating agent acceptable to the Issuers to authenticate Notes. An authenticating agent may authenticate Notes whenever the Trustee may do so. Each
reference in this Indenture to authentication by the Trustee includes authentication by such agent. An authenticating agent has the same rights as an Agent to deal with Holders or an Affiliate of
either of the Issuers. 

Section 2.03.
Registrar and Paying Agent. 

        The
Partnership, MarkWest Finance and the Subsidiary Guarantors shall maintain an office or agency where Notes may be presented for registration of transfer or for exchange ("Registrar")
and an office or agency in the City and State of New York where Notes may be presented for payment ("Paying Agent"). The Registrar shall keep a register of the Notes and of their transfer and
exchange. The Issuers may appoint one or more co-registrars and one or more additional paying agents. The term "Registrar" includes any co-registrar and the term "Paying Agent"
includes any additional paying agent. The Issuers may change any Paying Agent or Registrar without notice to any Holder. The Issuers shall notify the Trustee in writing of the name and address of any
Agent not a party to this Indenture. If the Issuers fail to appoint or maintain another entity as Registrar or Paying Agent, the Trustee shall act as such. The Partnership, MarkWest Finance or any of
their Subsidiaries may act as Paying Agent or Registrar. 

        The
Issuers initially appoint The Depository Trust Company ("DTC") to act as Depositary with respect to the Global Notes. 

        The
Issuers initially appoint the Trustee to act as the Registrar and Paying Agent and to act as Note Custodian with respect to the Global Notes. 

23

 

Section 2.04.
Paying Agent to Hold Money in Trust. 

        The
Issuers shall require each Paying Agent other than the Trustee to agree in writing that the Paying Agent will hold in trust for the benefit of Holders or the Trustee all money held
by the Paying Agent for the payment of principal, premium, if any, or interest or Additional Interest, if any, on the Notes, and will notify the Trustee of any default by the Partnership, MarkWest
Finance or the Subsidiary Guarantors in making any such payment. While any such default continues, the Trustee may require a Paying Agent to pay all money held by it to the Trustee. The Issuers at any
time may require a Paying Agent to pay all money held by it to the Trustee. Upon payment over to the Trustee, the Paying Agent (if other than an Issuer or a Subsidiary Guarantor) shall have no further
liability for the money. If an Issuer or a Subsidiary Guarantor acts as Paying Agent, it shall segregate and hold in a separate trust fund for the benefit of the Holders all money held by it as Paying
Agent. Upon any bankruptcy or reorganization proceedings relating to the Partnership or MarkWest Finance, the Trustee shall serve as Paying Agent for the Notes. 

Section 2.05.
Holder Lists. 

        The
Trustee shall preserve in as current a form as is reasonably practicable the most recent list available to it of the names and addresses of all Holders and shall otherwise comply
with TIA Section 312(a). If the Trustee is not the Registrar, the Issuers shall furnish to the Trustee at least seven Business Days before each Interest Payment Date and at such other times as
the Trustee may request in writing, a list in such form and as of such date as the Trustee may reasonably require of the names and addresses of the Holders of Notes and the Issuers shall otherwise
comply with TIA Section 312(a). 

Section 2.06.
Transfer and Exchange. 

        (a)   Transfer
and Exchange of Global Notes. A Global Note may not be transferred as a whole except by the Depositary to a nominee of the Depositary, by a nominee of
the Depositary to the Depositary or to another nominee of the Depositary, or by the Depositary or any such nominee to a successor Depositary or a nominee of such successor Depositary. All Global Notes
may be exchanged by the Issuers for Certificated Notes if (i) the Issuers deliver to the Trustee notice from the Depositary that it is unwilling or unable to continue to act as Depositary or
that it is no longer a clearing agency registered under the Exchange Act and, in either case, a successor Depositary is not appointed by the Issuers within 90 days after the date of such notice
from the Depositary, or (ii) if an Event of Default occurs and is continuing and the Depositary notifies the Trustee of its decision to exchange the Global Notes for Certificated Notes.
Whenever a Global Note is exchanged as a whole for one or more Certificated Notes, it shall be surrendered by the Holder thereof to the Trustee for cancellation. Whenever a Global
Note is exchanged in part for one or more Certificated Notes, it shall be surrendered by the Holder thereof to the Trustee and the Trustee shall make the appropriate notations to the Schedule
of Exchanges of Interests in the Global Notes attached thereto pursuant to Section 2.01 hereof. All Certificated Notes issued in exchange for a Global Note or any portion thereof shall
be registered in such names, and delivered, as the Depositary shall instruct the Trustee. Global Notes also may be exchanged or replaced, in whole or in part, as provided in Sections 2.07 and
2.10 hereof. Every Note authenticated and delivered in exchange for, or in lieu of, a Global Note or any portion thereof, pursuant to Section 2.07 or 2.10 hereof, shall be authenticated
and delivered in the form of, and shall be, a Global Note. A Global Note may not be exchanged for another Note other than as provided in this Section 2.06(a); however, beneficial
interests in a Global Note may be transferred and exchanged as provided in Section 2.06(b) or (f) hereof. 

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        (b)   Transfer and Exchange of Beneficial Interests in the Global Notes. The transfer and exchange of beneficial interests in the Global Notes shall be effected through the
Depositary, in accordance with the provisions of this Indenture and the Applicable Procedures. Beneficial interests in the Restricted Global Notes shall be subject to restrictions on transfer
comparable to those set forth herein to the extent required by the Securities Act. Transfers of beneficial interests in the Global Notes also shall require compliance with either subparagraph
(i) or (ii) below, as applicable, as well as one or more of the other following subparagraphs as applicable: 

        (i)    Transfer
of Beneficial Interests in the Same Global Note. Beneficial interests in any Restricted Global Note may be transferred to Persons who take delivery
thereof in the form of a beneficial interest in the same Restricted Global Note in accordance with the transfer restrictions set forth in the Private Placement Legend; provided, however, that
prior to the expiration of the Distribution Compliance Period transfers of beneficial interests in the Regulation S Global Note may not be made to a U.S. Person or for the account or
benefit of a U.S. Person (other than an Initial Purchaser). Beneficial interests in any Unrestricted Global Note may be transferred only to Persons who take delivery thereof in the form of a
beneficial interest in an Unrestricted Global Note. No written orders or instructions shall be required to be delivered to the Registrar to effect the transfers described in this
Section 2.06(b)(i). 

        (ii)   All
Other Transfers and Exchanges of Beneficial Interests in Global Notes. In connection with all transfers and exchanges of beneficial interests (other than a transfer
of a beneficial interest in a Global Note to a Person who takes delivery thereof in the form of a beneficial interest in the same Global Note), the transferor of such beneficial interest must
deliver to the Registrar (A) a written order from a Participant or an Indirect Participant given to the Depositary in accordance with the Applicable Procedures directing the Depositary to
credit or cause to be credited a beneficial interest in another Global Note in an amount equal to the beneficial interest to be transferred or exchanged and (B) instructions given in
accordance with the Applicable Procedures containing information regarding the Participant account to be credited with such increase. Upon an Exchange Offer by the Issuers in accordance with
Section 2.06(f) hereof, the requirements of this Section 2.06(b)(ii) shall be deemed to have been satisfied upon receipt by the Registrar of the instructions contained in
the Letters of Transmittal delivered by the holders of such beneficial interests in the Restricted Global Notes. Upon satisfaction of all of the requirements for transfer or exchange of beneficial
interests in Global Notes contained in this Indenture, the Notes and otherwise applicable under the Securities Act, the Trustee shall adjust the principal amount of the relevant Global Note(s)
pursuant to Section 2.06(h) hereof. 

        (iii)  Transfer
of Beneficial Interests to Another Restricted Global Note. A beneficial interest in any Restricted Global Note may be transferred to a Person who takes
delivery thereof in the form of a beneficial interest in another Restricted Global Note if the transfer complies with the requirements of clause (ii) above and the Registrar
receives the following: 

        (A)  if
the transferee will take delivery in the form of a beneficial interest in the 144A Global Note, then the transferor must deliver a certificate in the form of
Exhibit B hereto, including the certifications in item (1) thereof; 

        (B)  if
the transferee will take delivery in the form of a beneficial interest in the Regulation S Global Note, then the transferor must deliver a certificate in the
form of Exhibit B hereto, including the certifications in item (2) thereof; and 

        (C)  if
the transferee will take delivery in the form of a beneficial interest in the IAI Global Note, then the transferor must deliver (x) a certificate in the form
of Exhibit B hereto, including the certifications and certificates and Opinion of Counsel required by item (3)(c) thereof, if applicable. 

25

 

        (iv)  Transfer
and Exchange of Beneficial Interests in a Restricted Global Note for Beneficial Interests in the Unrestricted Global Note. A beneficial interest in any
Restricted Global Note may be exchanged by any holder thereof for a beneficial interest in an Unrestricted Global Note or transferred to a Person who takes delivery thereof in the form
of a beneficial interest in an Unrestricted Global Note if the exchange or transfer complies with the requirements of clause (ii) above and: 

        (A)  such
exchange or transfer is effected pursuant to an Exchange Offer in accordance with the applicable Registration Rights Agreement and the holder of the beneficial
interest to be transferred, in the case of an exchange, or the transferee, in the case of a transfer, is not (i) a broker-dealer, (ii) a Person participating in the distribution of the
Exchange Notes or (iii) a Person who is an affiliate (as defined in Rule 144) of the Partnership; 

        (B)  any
such transfer is effected pursuant to a Shelf Registration Statement in accordance with the applicable Registration Rights Agreement; 

        (C)  any
such transfer is effected by a Participating Broker-Dealer pursuant to an Exchange Offer Registration Statement in accordance with the applicable Registration Rights
Agreement; or 

        (D)  the
Registrar receives the following: 

        (i)    if
the holder of such beneficial interest in a Restricted Global Note proposes to exchange such beneficial interest for a beneficial interest in an Unrestricted Global
Note, a certificate from such holder in the form of Exhibit C hereto, including the certifications in item (1)(a) thereof; 

        (ii)   if
the holder of such beneficial interest in a Restricted Global Note proposes to transfer such beneficial interest to a Person who shall take delivery thereof in the
form of a beneficial interest in an Unrestricted Global Note, a certificate from such holder in the form of Exhibit B hereto, including the certifications in item (4) thereof; and 

        (iii)  in
each such case set forth in this subparagraph (D), an opinion of counsel in form reasonably acceptable to the Issuers to the effect that such exchange or transfer
is in compliance with the Securities Act, that the restrictions on transfer contained herein and in the Private Placement Legend are not required in order to maintain compliance with the Securities
Act and such beneficial interest is being exchanged or transferred in compliance with any applicable blue sky securities laws of any state of the United States. 

        If
any such transfer is effected pursuant to subparagraph (B) or (D) above at a time when an Unrestricted Global Note has not yet been issued, the Issuers shall
issue and, upon receipt of an authentication order in accordance with Section 2.02 hereof, the Trustee shall authenticate one or more Unrestricted Global Notes (accompanied by a notation of the
Guarantees duly endorsed by the Subsidiary Guarantors) in an aggregate principal amount equal to the principal amount of beneficial interests transferred pursuant to subparagraph (B) or
(D) above. 

        Beneficial
interests in an Unrestricted Global Note cannot be exchanged for, or transferred to Persons who take delivery thereof in the form of, a beneficial interest in a
Restricted Global Note. 

        (c)   Transfer
or Exchange of Beneficial Interests for Certificated Notes. A beneficial interest in a Global Note cannot be exchanged for, or transferred to Persons who
take delivery thereof in the form of, a Certificated Note, except in the circumstances specified in Section 2.06(a). 

        (d)   Transfer
and Exchange of Certificated Notes for Beneficial Interests. Certificated Notes cannot be exchanged for, or transferred to Persons who take delivery thereof in
the form of, a beneficial interest in a Global Note. 

26

 

        (e)   Transfer
and Exchange of Certificated Notes for Certificated Notes. Upon request by a Holder of Certificated Notes and such Holder's compliance with the provisions of
this Section 2.06(e), the Registrar shall register the transfer or exchange of Certificated Notes. Prior to such registration of transfer or exchange, the requesting Holder shall present or
surrender to the Registrar the Certificated Notes duly endorsed or accompanied by a written instruction of transfer in form satisfactory to the Registrar duly executed by such Holder or by his
attorney, duly authorized in writing. In addition, the requesting Holder shall provide any additional certifications, documents and information, as applicable, pursuant to the provisions of this
Section 2.06(e). 

        (i)    Restricted
Certificated Notes may be transferred to and registered in the name of Persons who take delivery thereof if the Registrar receives the following: 

        (A)  if
the transfer will be made pursuant to Rule 144A under the Securities Act, then the transferor must deliver a certificate in the form of Exhibit B
hereto, including the certifications in item (1) thereof; 

        (B)  if
the transfer will be made pursuant to Rule 903 or Rule 904, then the transferor must deliver a certificate in the form of Exhibit B hereto,
including the certifications in item (2) thereof; and 

        (C)  if
the transfer will be made pursuant to any other exemption from the registration requirements of the Securities Act, then the transferor must deliver a certificate in
the form of Exhibit B hereto, including the certifications, certificates and Opinion of Counsel required by item (3) thereof, if applicable. 

        (ii)   Any
Restricted Certificated Note may be exchanged by the Holder thereof for an Unrestricted Certificated Note or transferred to a Person or Persons who
take delivery thereof in the form of an Unrestricted Certificated Note if: 

        (A)  such
exchange or transfer is effected pursuant to an Exchange Offer in accordance with the applicable Registration Rights Agreement and the Holder, in the case of an
exchange, or the transferee, in the case of a transfer, is not (i) a broker-dealer, (ii) a Person participating in the distribution of the Exchange Notes or (iii) a Person who is
an affiliate (as defined in Rule 144) of the Partnership; 

        (B)  any
such transfer is effected pursuant to a Shelf Registration Statement in accordance with the applicable Registration Rights Agreement; 

        (C)  any
such transfer is effected by a Participating Broker-Dealer pursuant to an Exchange Offer Registration Statement in accordance with the applicable Registration Rights
Agreement; or 

        (D)  the
Registrar receives the following: 

        (i)    if
the Holder of such Restricted Certificated Notes proposes to exchange such Notes for an Unrestricted Certificated Note, a certificate from such Holder in the form of
Exhibit C hereto, including the certifications in item (1)(b) thereof; 

        (ii)   if
the Holder of such Restricted Certificated Notes proposes to transfer such Notes to a Person who shall take delivery thereof in the form of an Unrestricted
Certificated Note, a certificate from such Holder in the form of Exhibit B hereto, including the certifications in item (4) thereof; and 

        (iii)  in
each such case set forth in this subparagraph (D), an opinion of counsel in form reasonably acceptable to the Issuers to the effect that such exchange or transfer
is in compliance with the Securities Act, that the restrictions on transfer contained herein and in the Private Placement Legend are not required in order to maintain compliance with 

27

 

the
Securities Act, and such Restricted Certificated Note is being exchanged or transferred in compliance with any applicable blue sky securities laws of any state of the United States. 

        (iii)  A
Holder of Unrestricted Certificated Notes may transfer such Notes to a Person who takes delivery thereof in the form of an Unrestricted Certificated Note. Upon
receipt of a request for such a transfer, the Registrar shall register the Unrestricted Certificated Notes pursuant to the instructions from the Holder thereof. Unrestricted Certificated Notes cannot
be exchanged for or transferred to Persons who take delivery thereof in the form of a Restricted Certificated Note. 

        (f)    Exchange
Offer. Upon the occurrence of an Exchange Offer in accordance with a Registration Rights Agreement, the Issuers shall issue and, upon receipt of an
authentication order in accordance with Section 2.02, the Trustee shall authenticate (i) one or more Unrestricted Global Notes (accompanied by a notation of the Guarantees duly endorsed
by the Subsidiary Guarantors) in an aggregate principal amount equal to the principal amount of the beneficial interests in the Restricted Global Notes tendered for acceptance by Persons that are not
(x) broker-dealers (excluding broker-dealers that acquired such beneficial interests in Restricted Global Notes as a result of market-making activities or other trading activities (other than
such beneficial interests in Restricted Global Notes acquired directly from the Issuers or any of their affiliates (as defined in Rule 144) thereof)), (y) Persons participating in the
distribution of the Exchange Notes or (z) Persons who are affiliates of the Partnership and accepted for exchange in the Exchange Offer and (ii) Unrestricted Certificated Notes
(accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) in an aggregate principal amount equal to the principal amount of the Restricted Certificated Notes accepted
for exchange in the Exchange Offer. Concurrently with the issuance of such Notes, the Trustee shall cause the aggregate principal amount of the applicable Restricted Global Notes to be reduced
accordingly, and the Issuers shall execute and the Trustee shall authenticate and deliver to the Persons designated by the Holders of Restricted Certificated Notes so accepted Unrestricted
Certificated Notes in the appropriate principal amount. 

        (g)   Legends.
The following legends shall appear on the face of all Global Notes and Certificated Notes issued under this Indenture unless specifically stated otherwise in
the applicable provisions of this Indenture. 

        (i)    Private
Placement Legend. 

        (A)  Except
as permitted by subparagraph (B) below, each Global Note and each Certificated Note (and all Notes issued in exchange therefor or
substitution thereof) shall bear the legend in substantially the following form: 

"THIS
SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. NEITHER THIS SECURITY NOR ANY
INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS SUCH TRANSACTION IS
EXEMPT FROM, OR NOT SUBJECT TO, SUCH REGISTRATION. THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES ON ITS OWN BEHALF AND ON BEHALF OF ANY INVESTOR ACCOUNT FOR WHICH IT HAS PURCHASED
SECURITIES, TO OFFER, SELL OR OTHERWISE TRANSFER SUCH SECURITY, PRIOR TO THE DATE (THE "RESALE RESTRICTION TERMINATION DATE") THAT IS [IN THE CASE OF NOTES SOLD IN
RELIANCE ON RULE 144A UNDER THE SECURITIES ACT: TWO YEARS] [IN THE CASE OF NOTES SOLD IN RELIANCE ON REGULATION S UNDER THE
SECURITIES ACT: 40 DAYS] AFTER THE LATER OF THE ORIGINAL ISSUE DATE HEREOF AND THE LAST DATE ON WHICH EITHER 

28

 

ISSUER
OR ANY AFFILIATE OF EITHER ISSUER WAS THE OWNER OF THIS SECURITY (OR ANY PREDECESSOR OF SUCH SECURITY), ONLY (A) TO AN ISSUER OR ITS SUBSIDIARY, (B) PURSUANT TO A REGISTRATION
STATEMENT THAT HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT, (C) FOR SO LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A UNDER THE SECURITIES ACT, TO A PERSON IT
REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO
WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) PURSUANT TO OFFERS AND SALES THAT OCCUR OUTSIDE THE UNITED STATES WITHIN THE MEANING OF REGULATION S UNDER THE
SECURITIES ACT, (E) TO AN INSTITUTIONAL "ACCREDITED INVESTOR" WITHIN THE MEANING OF RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT THAT IS AN INSTITUTIONAL ACCREDITED
INVESTOR ACQUIRING THE SECURITY FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL ACCREDITED INVESTOR, IN EACH CASE IN A MINIMUM PRINCIPAL AMOUNT OF THE SECURITIES OF $250,000, FOR
INVESTMENT PURPOSES AND NOT WITH A VIEW TO OR FOR OFFER OR SALE IN CONNECTION WITH ANY DISTRIBUTION IN VIOLATION OF THE SECURITIES ACT, OR (F) PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT, SUBJECT TO THE ISSUERS' AND THE TRUSTEE'S RIGHT PRIOR TO ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSES (C), (D), (E) OR (F) TO
REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/ OR OTHER INFORMATION SATISFACTORY TO EACH OF THEM. THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE RESALE
RESTRICTION TERMINATION DATE." 

        (B)  Notwithstanding
the foregoing, any Global Note or Certificated Note issued pursuant to subparagraphs (b)(iv), (e)(ii), (e)(iii) or (f) to
this Section 2.06 (and all Notes issued in exchange therefor or substitution thereof) shall not bear the Private Placement Legend. 

        (ii)   Global
Note Legend. Each Global Note shall bear a legend in substantially the following form: 

"THIS
GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE INDENTURE GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF THE BENEFICIAL OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY
PERSON UNDER ANY CIRCUMSTANCES EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED PURSUANT TO SECTION 2.06 OF THE INDENTURE, (II) THIS GLOBAL
NOTE MAY BE EXCHANGED PURSUANT TO SECTION 2.06(a) OF THE INDENTURE, (III) THIS GLOBAL NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT TO SECTION 2.11 OF THE
INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO A SUCCESSOR DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF THE ISSUERS." 

"UNLESS
AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES IN DEFINITIVE FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A
NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY. 

29

 

UNLESS
THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) ("DTC"), TO THE ISSUERS OR THEIR AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS MAY BE REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO. OR SUCH OTHER ENTITY AS MAY BE REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN." 

        (h)   Cancellation
and/or Adjustment of Global Notes. At such time as all beneficial interests in a particular Global Note have been exchanged for Certificated Notes or
a particular Global Note has been redeemed, repurchased or canceled in whole and not in part, each such Global Note shall be returned to or retained and canceled by the Trustee in
accordance with Section 2.11 hereof. At any time prior to such cancellation, if any beneficial interest in a Global Note is exchanged for or transferred to a Person who will take
delivery thereof in the form of a beneficial interest in another Global Note or for Certificated Notes, the principal amount of Notes represented by such Global Note shall be reduced
accordingly and an endorsement shall be made on such Global Note, by the Trustee or by the Depositary at the direction of the Trustee, to reflect such reduction; and if the beneficial interest is
being exchanged for or transferred to a Person who will take delivery thereof in the form of a beneficial interest in another Global Note, such other Global Note shall be increased accordingly
and an endorsement shall be made on such Global Note, by the Trustee or by the Depositary at the direction of the Trustee, to reflect such increase. 

        (i)    General
Provisions Relating to Transfers and Exchanges. 

        (i)    To
permit registrations of transfers and exchanges, the Issuers shall execute and the Trustee shall authenticate Global Notes and Certificated Notes (in each case,
accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) upon the Issuers' order or at the Registrar's request. 

        (ii)   No
service charge shall be made to a holder of a beneficial interest in a Global Note or to a Holder of a Certificated Note for any registration of
transfer or exchange, but the Issuers may require payment of a sum sufficient to cover any transfer tax or similar governmental charge payable in connection therewith (other than any such transfer
taxes or similar governmental charge payable upon exchange or transfer pursuant to Sections 2.10, 3.06, 3.09, 4.06 and 9.05 hereof). 

        (iii)  The
Registrar shall not be required to register the transfer of or exchange any Note selected for redemption in whole or in part, except the unredeemed portion
of any Note being redeemed in part. 

        (iv)  All
Global Notes and Certificated Notes (in each case, accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) issued upon any
registration of transfer or exchange of Global Notes or Certificated Notes shall be the valid obligations of the Issuers and the Subsidiary Guarantors, evidencing the same debt, and entitled to the
same benefits under this Indenture, as the Global Notes or Certificated Notes surrendered upon such registration of transfer or exchange. 

        (v)   The
Issuers shall not be required (A) to issue, to register the transfer of or to exchange Notes during a period of 15 days before a selection of Notes for
redemption, (B) to register the transfer of or to exchange any Note so selected for redemption in whole or in part, except the 

30

 

unredeemed
portion of any Note being redeemed in part or (C) to register the transfer of or to exchange a Note between a record date and the next succeeding Interest Payment Date. 

        (vi)  Prior
to due presentment for the registration of a transfer of any Note, the Trustee, any Agent, the Issuers and the Subsidiary Guarantors may deem and treat the Person
in whose name any Note is registered as the absolute owner of such Note for the purpose of receiving payment of principal of and interest on such Notes and for all other purposes, and
none of the Trustee, any Agent, the Issuers or any Subsidiary Guarantor shall be affected by notice to the contrary. 

        (vii) The
Trustee shall authenticate Global Notes and Certificated Notes (in each case, accompanied by a notation of the Guarantees duly endorsed by the Subsidiary
Guarantors) in accordance with the provisions of Section 2.02 hereof. 

        (viii)   All
certifications, certificates and opinions of counsel required to be submitted to the Registrar pursuant to this Section 2.06 to effect a
transfer or exchange may be submitted by facsimile. 

        (ix)  Each
Holder of a Note agrees to indemnify the Issuers and the Trustee against any liability that may result from the transfer, exchange or assignment of such
Holder's Note in violation of any provision of this Indenture and/or applicable United States federal or state securities law. 

        (j)    Each
beneficial owner of an interest in a Note agrees to indemnify the Issuers and the Trustee against any liability that may result from the transfer, exchange
or assignment by such beneficial owner of such interest in violation of any provision of this Indenture and/or applicable United States federal or state securities law. 

        (k)   The
Trustee shall have no obligation or duty to monitor, determine or inquire as to compliance with any restrictions on transfer imposed under this Indenture or under
applicable law with respect to any transfer of any interest in any Note (including any transfers between or among beneficial owners of interest in any Global Note) other than to require
delivery of such certificate and other documentation or evidence as are expressly required by, and to do so if and when expressly required by the terms of, this Indenture, and to examine the same to
determine substantial compliance as to form with the express requirements hereof. 

Section 2.07.
Replacement Notes. 

        If
any mutilated Note is surrendered to the Trustee or either of the Issuers and the Trustee receives evidence to its satisfaction of the destruction, loss or theft of any Note,
the Issuers shall issue and the Trustee, upon the written order of the Issuers signed by one Officer of the Partnership and one Officer of MarkWest Finance, shall authenticate a replacement
Note (accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) if the Trustee's requirements are met. An indemnity bond must be supplied by the Holder that is
sufficient in the judgment of the Trustee and the Issuers to protect the Issuers, the Subsidiary Guarantors, the Trustee, any Agent and any authenticating agent from any loss that any of them may
suffer if a Note is replaced. The Issuers may charge for their expenses in replacing a Note. 

        Every
replacement Note is an additional obligation of the Issuers and the Subsidiary Guarantors and shall be entitled to all of the benefits of this Indenture equally and
proportionately with all other Notes duly issued hereunder. The provisions of this Section 2.07 are exclusive and shall preclude (to the extent lawful) all other rights and remedies with
respect to the replacement of mutilated, destroyed, lost or stolen Notes. 

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Section 2.08.
Outstanding Notes. 

        The
Notes outstanding at any time are all the Notes authenticated by the Trustee except for those canceled by it, those delivered to it for cancellation, those reductions in the
interests in a Global Note effected by the Trustee in accordance with the provisions hereof, and those described in this Section as not outstanding. Except as set forth in
Section 2.09 hereof, a Note does not cease to be outstanding because an Issuer or an Affiliate of an Issuer holds the Note. 

        If
a Note is replaced pursuant to Section 2.07 hereof, it ceases to be outstanding unless the Trustee receives proof satisfactory to it that the replaced Note is
held by a bona fide purchaser. 

        If
the principal amount of any Note is considered paid under Section 4.01 hereof, it ceases to be outstanding and interest (including Additional Interest, if applicable) on
it ceases to accrue. 

        If
the Paying Agent (other than an Issuer or a Subsidiary or an Affiliate of an Issuer) holds, on a redemption date or other maturity date, money sufficient to pay Notes payable on that
date, then on and after that date such Notes shall be deemed to be no longer outstanding and shall cease to accrue interest (including Additional Interest, if any). 

Section 2.09.
Treasury Notes. 

        In
determining whether the Holders of the required principal amount of Notes have concurred in any direction, waiver or consent, Notes owned by an Issuer, by any Subsidiary Guarantor or
by any Person directly or indirectly controlling or controlled by or under direct or indirect common control with the Partnership or any Subsidiary Guarantor, shall be considered as though not
outstanding, except that for the purposes of determining whether the Trustee shall be protected in relying on any such direction, waiver or consent, only Notes that a Responsible Officer of the
Trustee actually knows are so owned shall be so disregarded. 

Section 2.10.
Temporary Notes. 

        Until
definitive Notes are ready for delivery, the Issuers may prepare and the Trustee shall authenticate temporary Notes (accompanied by a notation of the Guarantees duly endorsed by
the Subsidiary Guarantors) upon a written order of the Issuers signed by one Officer of the Partnership and one Officer of MarkWest Finance. Temporary Notes shall be substantially in the form of
definitive Notes but may have variations that the Issuers consider appropriate for temporary Notes and as shall be reasonably acceptable to the Trustee. Without unreasonable delay, the Issuers shall
prepare and the Trustee shall authenticate definitive Notes (accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) in exchange for temporary Notes. 

        Holders
of temporary Notes shall be entitled to all of the benefits of this Indenture. 

Section 2.11.
Cancellation. 

        Either
of the Issuers at any time may deliver Notes to the Trustee for cancellation. The Registrar and Paying Agent shall forward to the Trustee any Notes surrendered to them for
registration of transfer, exchange or payment. The Trustee and no one else shall cancel all Notes surrendered for registration of transfer, exchange, payment, replacement or cancellation and shall
treat such canceled Notes in accordance with its documents retention policies. The Issuers may not issue new Notes to replace Notes that have been paid or that have been delivered to the Trustee for
cancellation. 

Section 2.12.
Defaulted Interest. 

        If
any of the Partnership, MarkWest Finance or any Subsidiary Guarantor defaults in a payment of interest on the Notes, it or they (to the extent of their obligations under the
Guarantees) shall pay the defaulted interest in any lawful manner plus, to the extent lawful, interest payable on the defaulted interest, to the Persons who are Holders on a subsequent special record
date, in each case at the rate 

32

 

provided
in the Notes and in Section 4.01 hereof. The Issuers shall notify the Trustee in writing of the amount of defaulted interest proposed to be paid on each Note and the date of the
proposed payment. The Issuers shall fix or cause to be fixed each such special record date and payment date, provided that no such special record date shall be less than 10 days prior to the
related payment date for such defaulted interest. At least 15 days before the special record date, the Issuers (or, upon the written request of the Issuers, the Trustee in the name and at the
expense of the Issuers) shall mail or cause to be mailed to Holders a notice that states the special record date, the related payment date and the amount of such interest to be paid. 

Section 2.13.
CUSIP Numbers. 

        The
Issuers in issuing the Notes may use "CUSIP" numbers (if then generally in use), and, if they do so, the Trustee shall use "CUSIP" numbers in notices of redemption as a convenience
to Holders; provided that any such notice may state that no representation is made as to the correctness of such numbers either as printed on the Notes or as contained in any notice of a redemption
and that reliance may be placed only on the other identification numbers printed on the Notes, and any such redemption shall not be affected by any defect in or omission of such numbers. The Issuers
will promptly notify the Trustee of any change in the "CUSIP" numbers. 

ARTICLE 3

REDEMPTION AND PREPAYMENT  

Section 3.01.
Notices to Trustee. 

        If
an Issuer elects to redeem Notes pursuant to the optional redemption provisions of Section 3.07 hereof, it shall furnish to the Trustee, at least ten Business Days (unless a
shorter period is acceptable to the Trustee) before the date of giving notice of the redemption pursuant to Section 3.03, an Officers' Certificate setting forth (i) the clause of this
Indenture pursuant to which the redemption shall occur, (ii) the redemption date, (iii) the principal amount of Notes to be redeemed, (iv) the redemption price and
(v) whether it requests the Trustee to give notice of such redemption. Any such notice may be
cancelled at any time prior to the mailing of notice of such redemption to any Holder and shall thereby be void and of no effect. 

Section 3.02.
Selection of Notes to Be Redeemed. 

        If
less than all of the Notes are to be redeemed at any time, the Trustee will select Notes for redemption as follows: 

        (a)   if
the Notes are listed for trading on a national securities exchange, in compliance with the requirements of the principal national securities exchange on which the
Notes are so listed; or 

        (b)   if
the Notes are not so listed or there are no such requirements, on a pro rata basis, by lot or by such method as the Trustee shall deem fair and appropriate. 

        No
Notes of $1,000 or less shall be redeemed in part. Notices of redemption shall be mailed by first class mail at least 30 but not more than 60 days before the redemption date to
each Holder of Notes to be redeemed at its registered address. Notices of redemption may not be conditional. 

        If
any Note is to be redeemed in part only, the notice of redemption that relates to that Note shall state the portion of the principal amount thereof to be redeemed. A new
Note in principal amount equal to the unredeemed portion of the original Note will be issued in the name of the Holder thereof upon cancellation of the original Note. Notes called for
redemption become due on the date fixed for redemption. On and after the redemption date, interest (including Additional Interest, if applicable) ceases to accrue on Notes or portions of them called
for redemption unless the Issuers default in making such redemption payment. 

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Section 3.03.
Notice of Redemption. 

        At
least 30 days but not more than 60 days before a redemption date, the Issuers shall mail or cause to be mailed, by first class mail, a notice of redemption to each
Holder whose Notes are to be redeemed at its registered address. 

        The
notice shall identify the Notes to be redeemed (including CUSIP numbers) and shall state: 

        (a)   the
redemption date; 

        (b)   the
redemption price; 

        (c)   if
any Note is being redeemed in part, the portion of the principal amount of such Note to be redeemed and that, after the redemption date upon surrender
of such Note, a new Note or Notes in principal amount equal to the unredeemed portion shall be issued upon cancellation of the original Note; 

        (d)   the
name and address of the Paying Agent; 

        (e)   that
Notes called for redemption (other than a Global Note) must be surrendered to the Paying Agent to collect the redemption price; 

        (f)    that,
unless the Issuers default in making such redemption payment, interest (including Additional Interest, if applicable) on Notes called for redemption ceases to
accrue on and after the redemption date; 

        (g)   the
paragraph of the Notes and/or Section of this Indenture pursuant to which the Notes called for redemption are being redeemed; and 

        (h)   that
no representation is made as to the correctness or accuracy of the CUSIP number, if any, listed in such notice or printed on the Notes. 

        If
any of the Notes to be redeemed is in the form of a Global Note, then the Issuers shall modify such notice to the extent necessary to accord with the procedures of the Depositary
applicable to redemption. 

        At
the Issuers' request, the Trustee shall give the notice of redemption in the Issuers' names and at their expense; provided, however, that the Issuers shall have delivered to the
Trustee, as provided in
Section 3.01, an Officers' Certificate requesting that the Trustee give such notice and setting forth the information to be stated in such notice as provided in the preceding paragraph. 

Section 3.04.
Effect of Notice of Redemption. 

        Once
notice of redemption is mailed in accordance with Section 3.03 hereof, Notes called for redemption become irrevocably due and payable on the redemption date at the redemption
price. A notice of redemption may not be conditional. 

Section 3.05.
Deposit of Redemption Price. 

        Not
later than 11:00 a.m., New York City time, on the redemption date, the Issuers shall deposit with the Trustee or with the Paying Agent (or, if the Partnership or a Subsidiary
thereof is acting as its own Paying Agent, segregate and hold in trust as provided in Section 2.04 hereof) money sufficient to pay the redemption price of, and accrued and unpaid interest
(including Additional Interest, if applicable) on, all Notes to be redeemed on that date. The Trustee or the Paying Agent shall promptly return to the Issuers any money deposited with the Trustee or
the Paying Agent by the Issuers in excess of the amounts necessary to pay the redemption price of, and accrued and unpaid interest (including Additional Interest, if applicable) on, all Notes to be
redeemed. 

34

 

        If
the Issuers comply with the provisions of the preceding paragraph, on and after the redemption date, interest (including Additional Interest, if applicable) shall cease to accrue on
the Notes or the portions of Notes called for redemption. If a Note is redeemed on or after an interest record date but on or prior to the related Interest Payment Date, then any accrued and
unpaid interest (including Additional Interest, if any) shall be paid to the Person in whose name such Note was registered at the close of business on such record date. If any
Note called for redemption shall not be so paid upon surrender for redemption because of the failure of the Issuers to comply with the preceding paragraph, interest (including Additional
Interest, if any) shall be paid on the unpaid principal, from the redemption date until such principal is paid, and to the extent lawful on any interest not paid on such unpaid principal, in each case
at the rate provided in the Notes and in Section 4.01 hereof. 

Section 3.06.
Notes Redeemed in Part. 

        Upon
surrender of a Note that is redeemed in part, the Issuers shall issue and, upon the Issuers' written request, the Trustee shall authenticate for the Holder at the expense of
the Issuers a new
Note (accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) equal in principal amount to the unredeemed portion of the Note surrendered. 

Section 3.07.
Optional Redemption. 

        (a)   Except
as set forth in clauses (b) and (c) of this Section 3.07, the Issuers shall not have the option to redeem the Notes prior to
November 1, 2009. On or after November 1, 2009, the Issuers shall have the option to redeem all or, from time to time, a part of the Notes, at the redemption prices (expressed as
percentages of principal amount) set forth below, plus accrued and unpaid interest (including Additional Interest, if any) to the applicable redemption date (subject to the rights of Holders of record
on the relevant record date to receive interest due on an Interest Payment Date that is on or prior to the redemption date), if redeemed during the twelve-month period beginning on November 1
of the years indicated below: 

	Year
 
	 	Percentage
	 
	2009	 	103.438	%
	2010	 	102.292	%
	2011	 	101.146	%
	2012 and thereafter	 	100.000	%

        (b)   On
or before November 1, 2009, the Issuers may redeem all or, from time to time, a part of the Notes upon not less than 30 nor more than 60 days' notice,
at a redemption price equal to: 

        (i)    100%
of the aggregate principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to the applicable redemption date (subject to the right of
Holders of record on the relevant record date to receive interest due on an Interest Payment Date that is on or prior to the redemption date), plus 

        (ii)   the
Make Whole Amount. 

        (c)   On
or before November 1, 2007, the Issuers may on any one or more occasions redeem in the aggregate up to 35% of the aggregate principal amount of Notes issued
hereunder with the net cash proceeds of one or more Equity Offerings at a redemption price equal to 106.875% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if
any, to the redemption date (subject to the right of Holders of record on a record date to receive interest due on the relevant Interest Payment Date that is on or prior to the redemption date);
provided that 

        (i)    at
least 65% of the aggregate principal amount of Notes issued hereunder remains outstanding after each such redemption; and 

35

  

        (ii)   any
redemption occurs within 60 days after the closing of such Equity Offering (without regard to any over-allotment option). 

        (d)   Any
redemption pursuant to this Section 3.07 shall be made pursuant to the provisions of Section 3.01 through 3.06 hereof. 

Section 3.08.
Mandatory Redemption. 

        Except
for any repurchase offers required to be made pursuant to Sections 4.06 and 4.07 hereof, the Issuers shall not be required to make mandatory redemption payments with
respect to the Notes. 

Section 3.09.
Offer to Purchase by Application of Net Proceeds. 

        In
the event that, pursuant to Section 4.07 hereof, the Issuers shall be required to commence a pro rata offer (an "Asset Sale Offer") to all Holders and all holders of other
Indebtedness that is pari passu with the Notes containing provisions similar to those set forth in this Indenture with respect to offers to purchase or
redeem with the Net Proceeds of sales of assets to purchase Notes and such other pair passu Indebtedness, it shall follow the procedures specified below. 

        The
Asset Sale Offer shall remain open for a period of at least 30 days following its commencement but no longer than 60 days, except to the extent that a longer period is
required by applicable law (the "Offer Period"). Promptly after the termination of the Offer Period (the "Purchase Date"), the Issuers shall purchase the principal amount of Notes required to be
purchased pursuant to Section 4.07 hereof (the "Offer Amount") or, if less than the Offer Amount has been tendered, all Notes tendered and not withdrawn in response to the Asset Sale Offer.
Payment for any Notes so purchased shall be made in the same manner as interest payments are made. 

        Upon
the commencement of an Asset Sale Offer, the Issuers shall send, by first class mail, a notice to the Trustee and each of the Holders, with a copy to the Trustee. The notice shall
contain all instructions and materials necessary to enable such Holders to tender Notes pursuant to the Asset Sale
Offer. The Asset Sale Offer shall be made to all Holders. The notice, which shall govern the terms of the Asset Sale Offer, shall state: 

        (a)   that
the Asset Sale Offer is being made pursuant to this Section 3.09 and Section 4.07 hereof and the length of time the Asset Sale Offer shall remain
open; 

        (b)   the
Offer Amount, the purchase price and the Purchase Date; 

        (c)   that
any Note not validly tendered or accepted for payment shall continue to accrue interest (including Additional Interest, if applicable); 

        (d)   that,
unless the Issuers default in making such payment, any Note accepted for payment pursuant to the Asset Sale Offer shall cease to accrue interest (including
Additional Interest, if applicable) after the Purchase Date; 

        (e)   that
Holders electing to have a Note purchased pursuant to any Asset Sale Offer shall be required to surrender the Note, with the form entitled "Option of Holder
to Elect Purchase" on the reverse of the Note completed, or transfer by book-entry transfer, to the Issuers, a depositary, if appointed by the Issuers, or a Paying Agent at the
address specified in the notice at least three days before the Purchase Date; 

        (f)    that
Holders shall be entitled to withdraw their election if the Issuers, the depositary or the Paying Agent, as the case may be, receives, not later than the expiration
of the Offer Period, a telegram, facsimile transmission or letter setting forth the name of the Holder, the principal amount of the Note the Holder delivered for purchase and a statement that
such Holder is withdrawing his election to have such Note purchased; 

36

 

        (g)   that,
if the aggregate principal amount of Notes surrendered by Holders exceeds the Offer Amount, the Issuers shall select the Notes to be purchased on a pro rata basis
(with such adjustments as may be deemed appropriate by the Issuers so that only Notes in denominations of $1,000, or integral multiples thereof, shall be purchased); and 

        (h)   that
Holders whose Notes were purchased only in part shall be issued new Notes (accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors)
equal in principal amount to the unpurchased portion of the Notes surrendered (or transferred by book-entry transfer). 

        On
the Purchase Date, the Issuers shall, to the extent lawful, accept for payment, on a pro rata basis to the extent necessary, the Offer Amount of Notes or portions thereof validly
tendered and not properly withdrawn pursuant to the Asset Sale Offer, or if less than the Offer Amount has been validly tendered and not properly withdrawn, all Notes so tendered and not withdrawn,
shall deposit by 11:00 a.m., New York time, with the Paying Agent or depositary an amount equal to the purchase price in respect of all Notes or portions thereof accepted for payment, and shall
deliver to the Trustee an Officers' Certificate stating that such Notes or portions thereof were accepted for payment by the Issuers in accordance with the terms of this Section 3.09. Upon
surrender and cancellation of a Certificated Note that is purchased in part, the Issuers shall promptly issue and the Trustee shall authenticate and deliver to the surrendering Holder of such
Certificated Note a new Certificated Note equal in principal amount to the unpurchased portion of such surrendered Certificated Note; provided that each such new Certificated
Note shall be in a principal amount of $1,000 or an integral multiple thereof. Respecting a Global Note that is purchased in part pursuant to an Asset Sale Offer, the Trustee shall make
an endorsement thereon to reduce the principal amount of such Global Note to an amount equal to the unpurchased portion of such Global Note, as provided in Section 2.06(h) hereof. The
depositary or the Paying Agent, as the case may be, shall promptly mail or deliver to each tendering Holder an amount equal to the purchase price of the Notes tendered by such Holder and accepted by
the Issuers for purchase, and the Issuers shall promptly issue a new Note (in each case, accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors), and the
Trustee, upon written request from the Issuers shall authenticate and mail or deliver such new Note to such Holder, in a principal amount equal to any unpurchased portion of the
Note surrendered. Any Note not so accepted shall be promptly mailed or delivered by the Issuers to the Holder thereof. The Issuers shall publicly announce the results of the Asset Sale
Offer on or as soon as practicable after the Purchase Date. 

ARTICLE 4

COVENANTS  

Section 4.01.
Payment of Notes. 

        The
Issuers shall pay or cause to be paid the principal of and premium, if any, and interest (including Additional Interest, if any) on the Notes in New York, New York on the dates and
in the manner provided in the Notes. Principal, premium, if any, and interest (including Additional Interest, if any) shall be considered paid on the date due if the Paying Agent, if other than an
Issuer or any Subsidiary Guarantor thereof, holds as of 11:00 a.m. Eastern Time on the due date money deposited by the Issuers in immediately available funds and designated for and sufficient
to pay all principal, premium, if any, and interest (including Additional Interest, if any) then due. The Issuers shall pay all Additional Interest, if any, in the same manner on the dates and in the
amounts set forth in the applicable Registration Rights Agreement. 

        The
Issuers shall pay interest (including post-petition interest in any proceeding under any Bankruptcy Law) on overdue principal and premium at the then applicable interest
rate on the Notes to the extent lawful. The Issuers shall pay interest (including post-petition interest in any proceeding 

37

 

under
any Bankruptcy Law) on overdue installments of interest (including Additional Interest, if any), without regard to any applicable grace period, at the same rate to the extent lawful. 

Section 4.02.
Maintenance of Office or Agency. 

        The
Issuers shall maintain an office or agency (which may be an office of the Trustee or an Affiliate of the Trustee, Registrar or co-registrar), where Notes may be
surrendered or presented for payment, where Notes may be surrendered for registration of transfer or for exchange and where notices and demands to or upon the Issuers or the Subsidiary Guarantors in
respect of the Notes and this Indenture may be served. The Issuers shall give prompt written notice to the Trustee of the location, and any change in the location, of such office or agency. If at any
time the Issuers shall fail to maintain any such required office or agency or shall fail to furnish the Trustee with the address thereof, such presentations, surrenders, notices and demands may be
made or served at the Corporate Trust Office of the Trustee. 

        The
Issuers may also from time to time designate one or more other offices or agencies where the Notes may be presented or surrendered for any or all such purposes and may from time to
time rescind such designations. Further, if at any time there shall be no such office or agency in the City and State of New York where the Notes may be presented or surrendered for payment, the
Issuers shall forthwith designate and maintain such an office or agency in the City and State of New York, in order that the Notes shall at all times be payable in the City and State of New York. The
Issuers shall give prompt written notice to the Trustee of any such designation or rescission and of any change in location of any such other office or agency. 

        The
Issuers hereby designate the Corporate Trust Office of the Trustee as one such office or agency of the Issuers in accordance with Section 2.03. 

Section 4.03.
Compliance Certificate. 

        (a)   The
Issuers and the Subsidiary Guarantors shall deliver to the Trustee, within 90 days after the end of each fiscal year, an Officers' Certificate stating that a
review of the activities of the Issuers and the Restricted Subsidiaries of the Partnership during the preceding fiscal year has been made under the supervision of the signing Officers with a view to
determining whether the Issuers and the Subsidiary Guarantors have kept, observed, performed and fulfilled their respective obligations under this Indenture and the Guarantees, respectively, and
further stating, as to each such Officer signing such certificate, that to the best of his or her knowledge each of such Issuers and such Subsidiary Guarantors, as the case may be, has kept, observed,
performed and fulfilled each and every covenant contained in this Indenture and is not in default in the performance or observance of any of the terms, provisions and conditions of this Indenture (or,
if a Default or Event of Default shall have occurred and be continuing, describing all such Defaults or Events of Default of which he or she may have knowledge and what action such Issuer or such
Subsidiary Guarantor, as the case may be, is taking or proposes to take with respect thereto). 

        (b)   [Intentionally
omitted]. 

        (c)   Each
of the Issuers shall, so long as any of the Notes are outstanding, deliver to the Trustee, forthwith upon any Officer of the General Partner or MarkWest Finance
becoming aware of any Default or Event of Default, an Officers' Certificate specifying such Default or Event of Default and what action the Issuers are taking or propose to take with respect thereto. 

Section 4.04.
Taxes. 

        The
Issuers shall pay, and shall cause each of its Restricted Subsidiaries to pay, prior to delinquency, all material taxes, assessments, and governmental levies except such as are
contested in good faith and by appropriate proceedings or where the failure to effect such payment is not adverse in any material respect to the Holders of the Notes. 

38

 

Section 4.05.
Stay, Extension and Usury Laws. 

        Each
of the Issuers and the Subsidiary Guarantors covenants (to the extent that it may lawfully do so) that it shall not at any time insist upon, plead, or in any manner whatsoever claim
or take the benefit or advantage of, any stay, extension or usury law wherever enacted, now or at any time hereafter in force, that may affect the covenants or the performance of this Indenture; and
each of the Issuers and the Subsidiary Guarantors (to the extent that it may lawfully do so) hereby expressly waives all benefit or advantage of any such law, and covenants that it shall not, by
resort to any such law, hinder, delay
or impede the execution of any power herein granted to the Trustee, but shall suffer and permit the execution of every such power as though no such law has been enacted. 

Section 4.06.
Change of Control. 

        (a)   If
a Change of Control occurs, each Holder of Notes shall have the right to require the Issuers to repurchase all or any part (equal to $1,000 or an integral multiple
thereof) of that Holder's Notes pursuant to the offer described below (the "Change of Control Offer"). In the Change of Control Offer, the Issuers shall offer a "Change of Control Payment" in cash
equal to 101% of the aggregate principal amount of Notes repurchased, plus accrued and unpaid interest (including Additional Interest, if any) thereon, if any, to the date of purchase (the "Change of
Control Payment"), subject to the rights of any Holder in whose name a Note is registered on a record date occurring prior to the Change of Control Payment Date to receive interest on an
Interest Payment Date that is on or prior to such Change of Control Payment Date. Within 30 days following any Change of Control, the Issuers shall mail a notice to each Holder describing the
transaction or transactions that constitute the Change of Control and offering to repurchase Notes on the Change of Control Payment Date specified in such notice, pursuant to the procedures required
by this Indenture and described in such notice. The Issuers shall comply with the requirements of Rule 14e-l under the Exchange Act and any other securities laws and regulations
thereunder to the extent such laws and regulations are applicable in connection with the repurchase of the Notes as a result of a Change of Control. To the extent that the provisions of any securities
laws or regulations conflict with the provisions of this Section 4.06, the Issuers shall comply with the applicable securities laws and regulations and shall not be deemed to have breached
their obligations under this Section 4.06 by virtue of such conflict. 

        (b)   Within
30 days following any Change of Control, the Issuers shall mail by first class mail, a notice to each Holder, with a copy of such notice to the Trustee.
The notice, which shall govern the terms of the Change of Control Offer, shall state, among other things: 

        (i)    that
a Change of Control has occurred and a Change of Control Offer is being made as provided for herein, and that, although Holders are not required to tender their
Notes, all Notes that are validly tendered shall be accepted for payment; 

        (ii)   the
Change of Control Payment and the Change of Control Payment Date, which will be no earlier than 30 days and no later than 60 days after the date such
notice is mailed (the "Change of Control Payment Date"); 

        (iii)  that
any Note accepted for payment pursuant to the Change of Control Offer (and duly paid for on the Change of Control Payment Date) shall cease to accrue
interest (including Additional Interest, if applicable) after the Change of Control Payment Date; 

        (iv)  that
any Notes (or portions thereof) not validly tendered shall continue to accrue interest (including Additional Interest, if applicable); 

        (v)   that
any Holder electing to have a Note purchased pursuant to any Change of Control Offer shall be required to surrender the Note, with the form entitled "Option
of Holder to Elect Purchase" on the reverse of the Note completed, or transfer by book-entry transfer, to the Issuers, 

39

 

a
depositary, if appointed by the Issuers, or a Paying Agent at the address specified in the notice at least one (1) Business Day before the Change of Control Payment Date; 

        (vi)  that
Holders shall be entitled to withdraw their election if the Issuers, the depositary or the Paying Agent, as the case may be, receives, not later than the
expiration of the Change of Control Offer, a telegram, facsimile transmission or letter setting forth the name of the Holder, the principal amount of the Note the Holder delivered for purchase
and a statement that such Holder is withdrawing his election to have such Note purchased; and 

        (vii) the
instructions and any other information necessary to enable Holders to tender their Notes (or portions thereof) and have such Notes (or portions thereof) purchased
pursuant to the Change of Control Offer. 

        (c)   On
the Change of Control Payment Date, the Issuers shall, to the extent lawful: 

        (i)    accept
for payment all Notes or portions thereof properly tendered and not withdrawn pursuant to the Change of Control Offer; 

        (ii)   deposit
by 11:00 a.m., New York time, with the Paying Agent or depositary an amount equal to the Change of Control Payment in respect of all Notes or portions
thereof so tendered; and 

        (iii)  deliver
or cause to be delivered to the Trustee for cancellation the Notes so accepted together with an Officers' Certificate stating the aggregate principal amount of
Notes or portions thereof being purchased by the Issuers. 

        (d)   The
depositary or the Paying Agent shall promptly mail to each Holder of Notes so tendered the Change of Control Payment for such Notes (or, if all the Notes are then in
global form, make such payment through the facilities of DTC), and the Issuers shall promptly issue a new Note (in each case, accompanied by a notation of the Guarantees duly endorsed by the
Subsidiary Guarantors), and the Trustee, upon written request from the Issuers, shall authenticate and mail (or cause to be transferred by book entry) to each Holder such new Note equal in
principal amount to any unpurchased portion of the Notes surrendered; provided that each such new Note shall be in a principal amount of $1,000 or an integral multiple thereof. The Issuers
shall publicly announce the results of the Change of Control Offer on or as soon as practicable after the Change of Control Payment Date. 

        (e)   The
provisions described in this Section 4.06 that require the Issuers to make a Change of Control Offer following a Change of Control shall be applicable
regardless of whether or not any other provisions of this Indenture are applicable. 

        (f)    Notwithstanding
the other provisions of this Section 4.06, the Issuers shall not be required to make a Change of Control Offer upon a Change of Control, and a
Holder will not have the right to require that the Issuers repurchase any Notes pursuant to a Change of Control Offer, if a third party makes the Change of Control Offer in the manner, at the times
and otherwise in compliance with the requirements set forth in this Indenture applicable to a Change of Control Offer made by the Issuers and purchases all Notes validly tendered and not withdrawn
under such Change of Control Offer. 

Section 4.07.
Asset Sales. 

        (a)   The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, consummate an Asset Sale unless: 

        (i)    such
Issuer (or the Restricted Subsidiary, as the case may be) receives consideration at the time of such Asset Sale at least equal to the fair market value of the
assets or Equity Interests issued or sold or otherwise disposed of; 

40

 

        (ii)   such
fair market value is determined by (a) an executive officer of the General Partner if the value is less than $5.0 million, as evidenced by an
Officers' Certificate delivered to the Trustee or (b) the Board of Directors of the General Partner if the value is $5.0 million or more, as evidenced by a resolution of such Board of
Directors of the General Partner; and 

        (iii)  at
least 75% of the consideration received by such Issuer or such Restricted Subsidiary is in the form of cash or Cash Equivalents. For purposes of this
clause (iii), each of the following shall be deemed to be cash: 

        (A)  any
liabilities (as shown on such Issuer's or such Restricted Subsidiary's most recent balance sheet) of the Partnership or any Restricted Subsidiary (other than
contingent liabilities and liabilities that are by their terms subordinated to the Notes or any Guarantee) that are assumed by the transferee of any such assets pursuant to a customary novation
agreement that releases the Partnership or such Restricted Subsidiary from further liability; and 

        (B)  any
securities, notes or other Obligations received by the Partnership or any such Restricted Subsidiary from such transferee that are within 90 days after the
Asset Sale (subject to ordinary settlement periods) converted by such Issuer or such Restricted Subsidiary into cash (to the extent of the cash received in that conversion). 

        (b)   Within
360 days after the receipt of any Net Proceeds from an Asset Sale, the Partnership or a Restricted Subsidiary may apply (or enter into a definitive
agreement for such application, provided that such application occurs within 90 days after the end of such 360-day period) such Net Proceeds at its option: 

        (i)    to
repay senior Indebtedness of the Partnership and/or its Restricted Subsidiaries (or to make an offer to repurchase or redeem any such Indebtedness, provided that such
repurchase or redemption closes within 45 days after the end of such 360-day period) with a permanent reduction in availability for any revolving credit Indebtedness; 

        (ii)   to
make a capital expenditure in a Permitted Business; 

        (iii)  to
acquire other long-term tangible assets that are used or useful in a Permitted Business; or 

        (iv)  to
invest in any other Permitted Business Investment or any other Permitted Investments other than Investments in Cash Equivalents, Interest Swaps or Currency
Agreements. 

Pending
the final application of any such Net Proceeds, the Partnership or a Restricted Subsidiary may temporarily reduce revolving credit borrowings or otherwise invest such Net Proceeds in any
manner that is not prohibited by this Indenture. 

        (c)   Any
Net Proceeds from Asset Sales that are not applied or invested as provided in Section 4.07(b) above will constitute "Excess Proceeds". When the
aggregate amount of Excess Proceeds exceeds $10.0 million, the Issuers will make an Asset Sale Offer to all Holders of Notes and all holders of other Indebtedness that is  pari passu with the Notes
containing provisions similar to those set forth in this Indenture with respect to offers to purchase or redeem with the
proceeds of sales of assets to purchase the maximum principal amount of Notes and such other pari passu Indebtedness that may be purchased out of the
Excess Proceeds. The offer price in any Asset Sale Offer will be equal to 100% of principal amount plus accrued and unpaid interest (including any Additional Interest in the case of the Notes), if
any, to the Purchase Date, subject to the rights of any Holder in whose name a Note is registered on a record date occurring prior to the Purchase Date to receive interest on an Interest
Payment Date that is on or prior to the Purchase Date, and will be payable in cash. If any Excess Proceeds remain after consummation of an Asset Sale Offer, the Partnership may use such Excess
Proceeds for any purpose not otherwise prohibited by this Indenture, including, without limitation, the repurchase or redemption of Indebtedness of the Issuers or any Subsidiary Guarantor 

41

 

that
is subordinated to the Notes or, in the case of any Subsidiary Guarantor, the Guarantee of such Subsidiary Guarantor. If the aggregate principal amount of Notes tendered into such Asset Sale
Offer exceeds the amount of Excess Proceeds allocated for repurchases of Notes pursuant to the Asset Sale Offer for Notes, the Trustee shall select the Notes to be purchased on a pro rata basis. Upon
completion of each Asset Sale Offer, the amount of Excess Proceeds shall be reset at zero. 

        (d)   The
Partnership shall comply with the requirements of Rule 14e-1 under the Exchange Act and any other securities laws and regulations thereunder to
the extent those laws and regulations are applicable in connection with each repurchase of Notes pursuant to an Asset Sale Offer. To the extent that the provisions of any securities laws or
regulations conflict with Section 3.09 or this Section 4.07, the Partnership shall comply with the applicable securities laws and regulations and shall not be deemed to have breached its
obligations under Section 3.09 or this Section 4.07 by virtue of such conflict. 

Section 4.08.
Restricted Payments. 

        (a)   The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, directly or indirectly: 

        (i)    declare
or pay any dividend or make any other payment or distribution on account of the Equity Interests of the Partnership or of any of its Restricted Subsidiaries
(including, without limitation, any payment in connection with any merger or consolidation involving the Partnership or any of its Restricted Subsidiaries) or to the direct or indirect holders of the
Equity Interests of the Partnership or of any of its Restricted Subsidiaries in their capacity as such (other than dividends or distributions payable in Equity Interests of the Partnership (other than
Disqualified Equity) and other than dividends or distributions payable to the Partnership or a Restricted Subsidiary of the Partnership). 

        (ii)   purchase,
redeem or otherwise acquire or retire for value (including, without limitation, in connection with any merger or consolidation involving an Issuer) any Equity
Interests of the Partnership or of any of its Restricted Subsidiaries (other than any such Equity Interests owned by the Partnership or any of its Restricted Subsidiaries); 

        (iii)  make
any payment on or with respect to, or purchase, redeem, defease or otherwise acquire or retire for value any Subordinated Obligation or Guarantor Subordinated
Obligation, except a payment of interest or principal at the Stated Maturity thereof; 

        (iv)  make
any Investment other than a Permitted Investment or a Permitted Business Investment (all such payments and other actions set forth in clauses (i) through
(iv) above being collectively referred to as "Restricted Payments"), 

unless,
at the time of and after giving effect to such Restricted Payment, no Default or Event of Default shall have occurred and be continuing or would occur as a consequence thereof and either: 

        (A)  if
the Fixed Charge Coverage Ratio for the Partnership's four most recent fiscal quarters for which internal financial statements are available is not less than 1.75 to
1.0, such Restricted Payment, together with the aggregate amount of all other Restricted Payments made by the Partnership and its Restricted Subsidiaries during the quarter in which such Restricted
Payment is made, is less than the sum, without duplication, of 

        (i)    Available
Cash from Operating Surplus as of the end of the immediately preceding quarter, plus 

        (ii)   the
sum of (1) the aggregate net cash proceeds of any (i) substantially concurrent capital contribution to the Partnership from any Person (other than to
a Restricted Subsidiary of the Partnership) made after the Issue Date or (ii) substantially 

42

 

concurrent
issuance and sale (other than to a Restricted Subsidiary of the Partnership) made after the Issue Date of Equity Interests (other than Disqualified Equity) of the Partnership or from the
issuance or sale (other than to a Restricted Subsidiary of the Partnership) made after the Issue Date of convertible or exchangeable Disqualified Equity or convertible or exchangeable debt securities
of the Partnership that have been converted into or exchanged for such Equity Interests (other than Disqualified Equity), and (2) the fair market value of any Permitted Business or
long-term tangible assets that are useful in a Permitted Business to the extent acquired in consideration of Equity Interests of the Partnership (other than Disqualified Equity) since the
Issue Date, plus 

        (iii)  to
the extent that any Restricted Investment that was made after the Issue Date is sold for cash or Cash Equivalents or otherwise liquidated or repaid for cash or Cash
Equivalents, the lesser of the refund of capital or similar payment made in cash or Cash Equivalents with respect to such Restricted Investment (less the cost of such disposition, if any) and the
initial amount of such Restricted Investment (other than to a Restricted Subsidiary of the Partnership), plus 

        (iv)  the
net reduction in Restricted Investments resulting from dividends, repayments of loans or advances, or other transfers of assets in each case to the Partnership or
any of its Restricted Subsidiaries from any Person (including, without limitation, Unrestricted Subsidiaries) or from redesignations of Unrestricted Subsidiaries as Restricted Subsidiaries, to the
extent such amounts have not been included in Available Cash from Operating Surplus for any period commencing on or after the Issue Date (items (ii), (iii) and (iv) of this
clause (A) being referred to as "Incremental Funds"), minus 

        (v)   the
aggregate amount of Incremental Funds previously expended pursuant to this clause (A) or clause (B) below; or 

        (B)  if
the Fixed Charge Coverage Ratio for the Partnership's four most recent fiscal quarters for which internal financial statements are available is less than 1.75 to 1.0,
such Restricted Payment, together with the aggregate amount of all other Restricted Payments made by the Partnership and its Restricted Subsidiaries during the quarter in which such Restricted Payment
is made (such Restricted Payments for purposes of this clause (B) meaning only distributions on common units of the Partnership, plus the related distribution on the general partner
interest), is less than the sum, without duplication, of: 

        (i)    $25.0 million
less the aggregate amount of all Restricted Payments made by the Partnership and its Restricted Subsidiaries pursuant to this
clause (B)(i) during the period ending on the last day of the
fiscal quarter of the Partnership immediately preceding the date of such Restricted Payment and beginning on the Issue Date, plus 

        (ii)   Incremental
Funds to the extent not previously expended pursuant to this clause (B) or clause (A) above. 

For
purposes of clauses (A) and (B) above, the term "substantially concurrent" means that either (x) the offering was consummated within 120 days of the date of
determination or (y) the offering was consummated within 24 months of the date of determination and the proceeds therefrom were used for the purposes expressly stated in the documents
related thereto and may be traced to such use by segregating, separating or otherwise specifically identifying the movement of such proceeds. 

43

 

        (b)   So
long as no Default has occurred and is continuing or would be caused thereby (except with respect to clause (i) below under which the payment of a
distribution or dividend is permitted), the preceding provisions of this Section 4.08 shall not prohibit: 

        (i)    the
payment by the Partnership or any of its Restricted Subsidiaries of any distribution or dividend within 60 days after the date of declaration thereof, if at
said date of declaration such payment would have complied with the provisions of this Indenture; 

        (ii)   the
redemption, repurchase, retirement, defeasance or other acquisition of any subordinated Indebtedness of the Partnership or any Subsidiary Guarantor or of any Equity
Interests of the Partnership in exchange for, or out of the net cash proceeds of, a substantially concurrent (a) capital contribution to the Partnership from any Person (other than a Restricted
Subsidiary of the Partnership) or (b) sale (other than to a Restricted Subsidiary of the Partnership) of Equity Interests (other than Disqualified Equity) of the Partnership (a sale will be
deemed substantially concurrent if such redemption, repurchase, retirement, defeasance or other acquisition occurs not more than 120 days after such sale); provided that the amount of any such
net cash proceeds that are utilized for any such redemption, repurchase, retirement, defeasance or other acquisition shall be excluded or deducted from the calculation of Available Cash from Operating
Surplus and Incremental Funds; 

        (iii)  the
defeasance, redemption, repurchase or other acquisition of any Subordinated Obligation or Guarantor Subordinated Obligation with the net cash proceeds from an
incurrence of, or in exchange for, Permitted Refinancing Indebtedness; 

        (iv)  the
payment of any distribution or dividend by a Restricted Subsidiary to the Partnership or to the holders of the Equity Interests (other than Disqualified Equity) of
such Restricted Subsidiary on a pro rata basis; and 

        (v)   the
repurchase, redemption or other acquisition or retirement for value of any Equity Interests of the Partnership or of any of its Restricted Subsidiaries pursuant to
any management equity subscription agreement or equity option agreement or other employee benefit plan or to satisfy obligations under any Equity Interests appreciation rights or option plan or
similar arrangement; provided that the aggregate price paid for all such repurchased, redeemed, acquired or retired Equity Interests shall not exceed $3.0 million in any calendar year. 

        In
computing the amount of Restricted Payments previously made for purposes of Section 4.08(a), Restricted Payments made under clauses (i) (but only if the declaration of
such dividend or other distribution has not been counted in a prior period) and, to the extent of amounts paid to holders other than the Partnership or any of its Restricted Subsidiaries,
(iv) of this Section 4.08(b) shall be included, and Restricted Payments made under clauses (ii), (iii) and (v) and, except to the extent noted above, (iv) of this
Section 4.08(b) shall not be included. The amount of all Restricted Payments (other than cash) shall be the fair market value on the date of the Restricted Payment of the asset(s) or securities
proposed to be transferred or issued by the Partnership or such Restricted Subsidiary, as the case may be, pursuant to the Restricted Payment. The fair market value of any assets or securities that
are required to be valued by this Section 4.08 shall be determined, in the case of amounts under $5.0 million, by an officer of the General Partner and, in the case of amounts over
$5.0 million, by the Board of Directors of the General Partner whose resolution with respect thereto shall be delivered to the Trustee. 

Section 4.09.
Incurrence of Indebtedness and Issuance of Disqualified Equity. 

        (a)   The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, directly or indirectly, create, incur, issue, assume, guarantee or otherwise
become directly or indirectly liable, contingently or otherwise, with respect to (collectively, "incur") any Indebtedness (including Acquired Debt), and the Partnership will not issue any Disqualified
Equity and will not permit any of its 

44

 

Restricted
Subsidiaries to issue any Disqualified Equity; provided, however, that the Partnership and any Restricted Subsidiary may incur Indebtedness (including Acquired Debt), and the Partnership
and the Restricted Subsidiaries may issue Disqualified Equity, if the Fixed Charge Coverage Ratio for the Partnership's most recently ended four full fiscal quarters for which internal financial
statements are available immediately preceding the date on which such additional Indebtedness is incurred or such Disqualified Equity is issued would have been at least 2.0 to 1.0, determined on a pro
forma basis (including a pro forma application of the net proceeds therefrom), as if the additional Indebtedness had been incurred, or the Disqualified Equity had been issued, as the case may be, at
the beginning of such four-quarter period. 

        (b)   Notwithstanding
the prohibitions of Section 4.09(a), so long as no Default or Event of Default shall have occurred and be continuing or would be caused thereby,
the Partnership and its Restricted Subsidiaries may incur any of the following items of Indebtedness (collectively, "Permitted Debt"): 

        (i)    the
incurrence by the Partnership and any Restricted Subsidiary of Indebtedness under Credit Facilities and the guarantees thereof; provided that the aggregate principal
amount of all Indebtedness of the Partnership and the Restricted Subsidiaries incurred pursuant to this clause (i) and outstanding under all Credit Facilities after giving effect to such
incurrence does not exceed the greater of (A) $200.0 million or (B) 15% of the Consolidated Net Tangible Assets of the Partnership, in each case less the aggregate amount of all
repayments of Indebtedness under any Credit Facility that have been made by the Partnership or any of its Restricted Subsidiaries with Net Proceeds from Asset Sales to the extent such repayments
constitute a permanent reduction of commitments under such Credit Facility; 

        (ii)   the
incurrence by the Partnership and its Restricted Subsidiaries of Existing Indebtedness (other than under the Credit Facilities); 

        (iii)  the
incurrence by the Partnership and the Subsidiary Guarantors of Indebtedness represented by the Notes issued and sold in the Offering, any Exchange Notes and the
Guarantees and the related Obligations; 

        (iv)  the
incurrence by the Partnership or any of its Restricted Subsidiaries of Indebtedness represented by Capital Lease Obligations, mortgage financings or purchase money
obligations, in each case, incurred for the purpose of financing all or any part of the purchase price or cost of construction or improvement of property, plant or equipment used in the business of
the Partnership or such Restricted Subsidiary, in an aggregate principal amount including all Permitted Refinancing Indebtedness incurred to refund, refinance or replace any Indebtedness incurred
pursuant to this clause (iv) not to exceed $10.0 million at any time outstanding; 

        (v)   the
incurrence by the Partnership or any of its Restricted Subsidiaries of Permitted Refinancing Indebtedness in exchange for, or the net proceeds of which are used to
refund, refinance or replace, Indebtedness that was permitted by this Indenture to be incurred under Section 4.09(a) or clause (ii) or (iii) of this
Section 4.09(b) or this clause (v); 

        (vi)  the
incurrence by the Partnership or any of its Restricted Subsidiaries of intercompany Indebtedness between or among the Partnership and any of its Restricted
Subsidiaries; provided, however, that: 

        (A)  if
the Partnership is the obligor on such Indebtedness and a Subsidiary Guarantor is not the obligee, such Indebtedness must be expressly subordinated to the prior
payment in full in cash of all Obligations with respect to the Notes, or if a Subsidiary Guarantor is the obligor on such Indebtedness and neither the Partnership nor another Subsidiary Guarantor is
the obligee, such Indebtedness must be expressly subordinated to the prior payment in full in cash of all Obligations with respect to the Guarantee of such Subsidiary Guarantor; and 

45

 

        (B)  (i) any
subsequent issuance or transfer of Equity Interests that results in any such Indebtedness being held by a Person other than the Partnership or a
Restricted Subsidiary thereof and (ii) any sale or other transfer of any such Indebtedness to a Person that is not either the Partnership or a Restricted Subsidiary thereof, shall be deemed, in
each case, to constitute an incurrence of such Indebtedness by the Partnership or such Restricted Subsidiary, as the case may be, that was not permitted by this clause (vi); 

        (vii) the
incurrence by the Partnership or any of its Restricted Subsidiaries of Hedging Obligations that are incurred for the purpose of fixing or hedging (but not for
speculative purposes) (A) foreign currency exchange rate risks of the Partnership or any Restricted Subsidiary, (B) interest rate risks with respect to any floating rate Indebtedness of
the Partnership or any Restricted Subsidiary that is permitted by the terms of this Indenture to be outstanding or (C) commodities pricing risks of the Partnership or any Restricted Subsidiary
in respect of Hydrocarbons used, produced, processed or sold by the Partnership or any of its Restricted Subsidiaries; 

        (viii)   the
guarantee by the Partnership or any of its Restricted Subsidiaries of Indebtedness of the Partnership or any of its Restricted Subsidiaries that was
permitted to be incurred by another provision of this Section 4.09; provided, that in the event such Indebtedness that is being guaranteed is a Subordinated Obligation or a Guarantor
Subordinated Obligation, then the guarantee shall be subordinated in right of payment to the Notes or the Guarantee, as the case may be; 

        (ix)  bid,
performance, surety and appeal bonds incurred in the ordinary course of business, including guarantees and obligations respecting standby letters of credit
supporting such obligations, to the extent not drawn (in each case other than an obligation for money borrowed); and 

        (x)   the
incurrence by the Partnership or any of its Restricted Subsidiaries of additional Indebtedness in an aggregate principal amount at any time outstanding not to exceed
$25.0 million. 

        (c)   For
purposes of determining compliance with this Section 4.09, in the event that an item of proposed Indebtedness meets the criteria of more than one of the
categories of Permitted Debt described in paragraphs (b)(i) through (b)(x) above, or is entitled to be incurred pursuant to Section 4.09(a), the Partnership shall be permitted to
classify (or later reclassify in whole or in part) such item of Indebtedness on the date of its incurrence in any manner that complies with this Section 4.09. An item of Indebtedness may be
divided and classified in one or more of the types of Permitted Indebtedness. Any Indebtedness under Credit Facilities on the Issue Date shall be considered incurred under Section 4.09(a). 

        (d)   The
accrual of interest, the accretion or amortization of original issue discount, the payment of interest on any Indebtedness in the form of additional Indebtedness
with the same terms, and the payment of dividends on Disqualified Equity in the form of additional shares of the same class of Disqualified Equity shall not be deemed to be an incurrence of
Indebtedness or an issuance of Disqualified Equity for purposes of this Section 4.09; provided, in each such case, that the amount thereof is included in Fixed Charges of the Partnership as
accrued. 

Section 4.10.
Liens. 

        The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, directly or indirectly, create, incur, assume or suffer to exist any Lien of any kind securing
Indebtedness upon any asset now owned or hereafter acquired, except Permitted Liens, without making effective provision whereby all Obligations due under the Notes and this Indenture or any Guarantee,
as applicable, will be secured by a Lien equally and ratably with (or prior to in the case of Liens with respect to 

46

 

Subordinated
Obligations or Guarantor Subordinated Obligations, as the case may be) any and all Obligations thereby secured for so long as any such Obligations shall be so secured. 

Section 4.11.
Dividend and Other Payment Restrictions Affecting Subsidiaries. 

        (a)   The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, directly or indirectly, create or permit to exist or become effective any
encumbrance or restriction on the ability of any Restricted Subsidiary to: 

        (i)    pay
dividends or make any other distributions on its Equity Interests to the Partnership or any of the Partnership's Restricted Subsidiaries, or pay any indebtedness or
other obligations owed to the Partnership or any of the other Restricted Subsidiaries; 

        (ii)   make
loans or advances to or make other Investments in the Partnership or any of the other Restricted Subsidiaries; or 

        (iii)  transfer
any of its properties or assets to the Partnership or any of the other Restricted Subsidiaries. 

        (b)   The
restrictions contained in Section 4.11(a) shall not apply to encumbrances or restrictions existing under or by reason of: 

        (i)    agreements
as in effect on the Issue Date and any amendments, modifications, restatements, renewals, increases, supplements, refundings, replacements or refinancings of
any such agreements or any Existing Indebtedness to which such agreement relates, provided that such amendments, modifications, restatements, renewals, increases, supplements, refundings, replacements
or refinancings are no more restrictive, taken as a whole, with respect to such distribution, dividend and other payment restrictions and loan or investment restrictions than those contained in such
agreement, as in effect on the Issue Date; 

        (ii)   this
Indenture, the Notes and the Guarantees; 

        (iii)  applicable
law; 

        (iv)  any
instrument governing Indebtedness or Equity Interests of a Person acquired by the Partnership or any of its Restricted Subsidiaries as in effect at the time of such
acquisition (except to the extent such Indebtedness was incurred in connection with or in contemplation of such acquisition), which encumbrance or restriction is not applicable to any Person, or the
property or assets of any Person, other than such Person, or the property or assets of such Person, so acquired, provided that, in the case of Indebtedness, such Indebtedness was permitted by the
terms of this Indenture to be incurred; 

        (v)   customary
non-assignment provisions in Hydrocarbon purchase and sale or exchange agreements or similar operational agreements or in licenses and leases
entered in the ordinary course of business and consistent with past practices; 

        (vi)  Capital
Lease Obligations, mortgage financings or purchase money obligations, in each case for property acquired in the ordinary course of business that impose
restrictions on the property so acquired of the nature described in clause (iii) of Section 4.11(a); 

        (vii) any
agreement for the sale or other disposition of a Restricted Subsidiary that restricts distributions by that Restricted Subsidiary pending its sale or other
disposition, provided that such sale or disposition is consummated, or such restrictions are canceled or terminated or lapse, within 90 days; 

        (viii)   Permitted
Refinancing Indebtedness, provided that the restrictions contained in the agreements governing such Permitted Refinancing Indebtedness are no
more restrictive, taken as a whole, than those contained in the agreements governing the Indebtedness being refinanced; 

47

  

        (ix)  Liens
securing Indebtedness otherwise permitted to be incurred pursuant to the provisions of Section 4.10 that limit the right of the Partnership or any of its
Restricted Subsidiaries to dispose of the assets subject to such Lien; 

        (x)   provisions
with respect to the disposition or distribution of assets or property in joint venture agreements, asset sale agreements, stock sale agreements and other
similar agreements entered into in the ordinary course of business; 

        (xi)  any
agreement or instrument relating to any property or assets acquired after the Issue Date, so long as such encumbrance or restriction relates only to the property or
assets so acquired and is not and was not created in anticipation of such acquisitions; and 

        (xii) restrictions
on cash or other deposits or net worth imposed by customers under contracts entered into in the ordinary course of business. 

Section 4.12.
Transactions With Affiliates. 

        (a)   The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, make any payment to, or sell, lease, transfer or otherwise dispose of any of its
properties or assets to, or purchase any property or assets from, or enter into or make or amend any transaction, contract, agreement, understanding, loan, advance or guarantee with, or for the
benefit of, any Affiliate (each, an "Affiliate Transaction"), unless: 

        (i)    such
Affiliate Transaction is on terms that are no less favorable to the Partnership or the relevant Restricted Subsidiary than those that would have been obtained in a
comparable transaction by the Partnership or such Restricted Subsidiary with an unrelated Person; and 

        (ii)   the
Partnership delivers to the Trustee: 

        (A)  with
respect to any Affiliate Transaction or series of related Affiliate Transactions involving aggregate consideration in excess of $5.0 million but less than or
equal to $25.0 million, an Officers' Certificate certifying that such Affiliate Transaction complies with this Section 4.12 and that such Affiliate Transaction has been approved by a
majority of the disinterested members of the Board of Directors of the General Partner; and 

        (B)  with
respect to any Affiliate Transaction or series of related Affiliate Transactions involving aggregate consideration in excess of $25.0 million, (i) a
resolution of the Board of Directors of the General Partner set forth in an Officers' Certificate certifying that such Affiliate Transaction complies with this Section 4.12 and that such
Affiliate Transaction has been approved by a majority of the disinterested members of the Board of Directors of the General Partner and (ii) an opinion as to the fairness to the Partnership of
such Affiliate Transaction from a financial point of view issued by an accounting, appraisal or investment banking firm of national standing recognized as an expert in rendering fairness opinions on
transactions such as those proposed, provided that the opinion in clause (ii) shall not be required in the case of any Affiliate Transaction or series of related Affiliate Transactions
(1) involving aggregate consideration of less than or equal to $50.0 million and (2) between the Partnership or any of its Restricted Subsidiaries and any Affiliate thereof in
which the Partnership beneficially owns 50% or less of the Voting Stock and one or more Persons not Affiliated with the Partnership beneficially own (together) a percentage of Voting Stock at least
equal to the interest in Voting Stock of such Affiliate beneficially owned by the Partnership. 

48

 

        (b)   The
following items shall not be deemed to be Affiliate Transactions and, therefore, shall not be subject to the provisions of Section 4.11(a): 

        (i)    any
employment, equity option or equity appreciation agreement or plan entered into by the Partnership or any of its Restricted Subsidiaries in the ordinary course of
business; 

        (ii)   transactions
between or among the Partnership and/or its Restricted Subsidiaries; 

        (iii)  Restricted
Payments that are permitted by Section 4.08; 

        (iv)  transactions
effected in accordance with the terms of (A) corporate sharing agreements that are with the Partnership and its Subsidiaries with respect to general
overhead and other administrative matters and (B) other agreements that are identified in Schedule B to this Indenture, in each case as such agreements are in effect on the Issue Date,
and any amendment or replacement of any of such agreements so long as such amendment or replacement agreement is no less advantageous to the Partnership in any material respect than the agreement so
amended or replaced; 

        (v)   customary
compensation, indemnification and other benefits made available to officers, directors or employees of the Partnership or a Restricted Subsidiary, including
reimbursement or advancement of out-of-pocket expenses and provisions of officers' and directors' liability insurance; and 

        (vi)  sales
of Equity Interests (other than Disqualified Equity) to Affiliates of the Partnership. 

Section 4.13.
Additional Subsidiary Guarantees. 

        If,
after the Issue Date, any Restricted Subsidiary of the Partnership that is not already a Subsidiary Guarantor guarantees any other Indebtedness of either of the Issuers or any
Indebtedness of the Operating Company, or if the Operating Company, if not then a Subsidiary Guarantor, guarantees any other Indebtedness of either of the Issuers or incurs any Indebtedness under any
Credit Facility, then in either case such Subsidiary must become a Subsidiary Guarantor by executing a supplemental indenture substantially in the form of Annex A hereto and delivering an Opinion of
Counsel and Officers' Certificate to the Trustee pursuant to Section 9.06 within 10 Business Days of the date on which it guaranteed or incurred such Indebtedness. Notwithstanding the
preceding, any Guarantee of a Restricted Subsidiary that was incurred pursuant to this Section 4.13 shall provide by its terms that it shall be automatically and unconditionally released upon
the release or discharge of the guarantee which resulted in the creation of such Restricted Subsidiary's Guarantee, except a discharge or release by, or as a result of payment under, such guarantee. 

Section 4.14.
Designation of Restricted and Unrestricted Subsidiaries. 

        (a)   The
Board of Directors of the General Partner may designate any Restricted Subsidiary of the Partnership to be an Unrestricted Subsidiary if that designation would not
cause a Default or Event of Default. If a Restricted Subsidiary is designated as an Unrestricted Subsidiary, all outstanding Investments owned by the Partnership and its Restricted Subsidiaries in the
Subsidiary so designated will be deemed to be an Investment made as of the time of such designation and will reduce the amount available for Restricted Payments under Section 4.08(a), or
represent Permitted Investments or Permitted Business Investments, as applicable. All such outstanding Investments will be valued at their fair market value at the time of such designation. That
designation will only be permitted if such Restricted Payment, Permitted Investments or Permitted Business Investments would be permitted under this Indenture at that time and such Restricted
Subsidiary otherwise complies with the definition of an Unrestricted Subsidiary. All Subsidiaries of an Unrestricted Subsidiary shall also be Unrestricted Subsidiaries. Upon the designation of a
Restricted Subsidiary that is a Subsidiary Guarantor as an Unrestricted Subsidiary, the Guarantee of such entity shall be released and the Trustee shall be authorized to take such actions as may be
appropriate to reflect such release. 

49

 

        (b)   The
Board of Directors of the General Partner may at any time designate any Unrestricted Subsidiary to be a Restricted Subsidiary; provided that such designation shall
be deemed to be an incurrence of Indebtedness by a Restricted Subsidiary of the Partnership of any outstanding Indebtedness of such Unrestricted Subsidiary and such designation shall only be permitted
if (1) such Indebtedness is permitted under Section 4.09, calculated on a pro forma basis as if such designation had occurred at the beginning of the four-quarter reference
period; and (2) no Default or Event of Default would be in existence following such designation. 

Section 4.15.
Business Activities. 

        The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, engage in any business other than Permitted Businesses. 

        MarkWest
Finance shall not incur Indebtedness unless (a) the Partnership is a co-obligor or guarantor of such Indebtedness or (b) the net proceeds of such
Indebtedness are loaned to the Partnership, used to acquire outstanding debt securities issued by the Partnership or used to repay Indebtedness of the Partnership as permitted under
Section 4.09. MarkWest Finance shall not engage in any business not related directly or indirectly to obtaining money or arranging financing for the Partnership or its Restricted Subsidiaries. 

Section 4.16.
Sale and Leaseback Transactions. 

        The
Partnership shall not, and shall not permit any of its Restricted Subsidiaries to, enter into any sale and leaseback transaction; provided that the Partnership or any Restricted
Subsidiary that is a Subsidiary Guarantor may enter into a sale and leaseback transaction if: 

        (a)   the
Partnership or that Subsidiary Guarantor, as applicable, could have (i) incurred Indebtedness in an amount equal to the Attributable Debt relating to such
sale and leaseback transaction under Section 4.09(a), and (ii) incurred a Lien to secure such Indebtedness pursuant to Section 4.10; provided, however, that
clause (i) of this clause (a) shall be suspended during any period in which the Partnership and its Restricted Subsidiaries are not subject to the Suspended Covenants; 

        (b)   the
gross cash proceeds of that sale and leaseback transaction are at least equal to the fair market value, as determined in good faith by the Board of Directors of the
General Partner, of the property that is the subject of such sale and leaseback transaction; and 

        (c)   the
transfer of assets in that sale and leaseback transaction is permitted by, and the Partnership applies the proceeds of such transaction in compliance with, the
provisions set forth under Sections 3.09 and 4.07. 

Section 4.17.
Payments for Consent. 

        The
Partnership shall not, and shall not permit any of its Subsidiaries to, directly or indirectly, pay or cause to be paid any consideration to or for the benefit of any Holder of Notes
for or as an inducement to any consent, waiver or amendment of any of the terms or provisions of this Indenture or the Notes unless such consideration is offered to be paid and is paid to all Holders
of the Notes that consent, waive or agree to amend in the time frame set forth in the solicitation documents relating to such consent, waiver or agreement. 

Section 4.18.
Reports. 

        (a)   Whether
or not required by the SEC, so long as any Notes are outstanding, the Partnership will file with the SEC (unless the SEC will not accept such a filing) within
the time periods specified in 

50

 

the
SEC's rules and regulations, and upon request, the Partnership will furnish (without exhibits) to the Trustee for delivery to the Holders of Notes: 

        (i)    all
quarterly and annual financial information that would be required to be contained in a filing with the SEC on Forms 10-Q and 10-K if the
Partnership were required to file such forms, including a "Management's discussion and analysis of financial condition and results of operations" and, with respect to the annual information only, a
report on the annual financial statements by the Partnership's certified independent accountants; and 

        (ii)   all
current reports that would be required to be filed with the SEC on Form 8-K if the Partnership were required to file such reports. 

        (b)   If
as of the end of any such quarterly or annual period referred to in Section 4.18(a), the Partnership has designated any of its Subsidiaries as Unrestricted
Subsidiaries, then the Partnership shall deliver (promptly after such SEC filing referred to in Section 4.18(a)) to the Trustee for delivery to the Holders of the Notes quarterly and annual
financial information required by Section 4.18(a) as revised to include a reasonably detailed presentation, either on the face of the financial statements or in the footnotes thereto, and in
"Management's discussion and analysis of financial condition and results of operations," of the financial condition and results of operations of the Partnership and its Restricted Subsidiaries
separate from the financial condition and results of operations of the Unrestricted Subsidiaries of the Partnership. 

        (c)   In
addition, whether or not required by the SEC, the Partnership will make such information available to securities analysts, investors and prospective investors upon
request. In addition, upon request the Partnership shall furnish the Trustee such other non-confidential information, documents and other reports which the Partnership is required to file
with the SEC pursuant to Section 13 or Section 15(d) of the Exchange Act. 

        (d)   For
so long as any Series A Notes remain outstanding (unless the Partnership is subject to the reporting requirements of the Exchange Act), the Partnership and
the Subsidiary Guarantors shall furnish to the Holders, upon their request, the information required to be delivered pursuant to Rule 144A(d)(4) under the Securities Act to the extent
such information is not provided pursuant to Sections 4.18(a) and 4.18(b). 

        (e)   Delivery
of reports, information and documents to the Trustee pursuant to this Section 4.18 is for informational purposes only and the Trustee's receipt of such
shall not constitute constructive notice of any information contained therein or determinable from information contained therein, including the Partnership's compliance with any of its covenants
hereunder (as to which the Trustee is entitled to rely exclusively on Officers' Certificates). 

Section 4.19.
Suspension of Covenants. 

        During
any period when the Notes have an Investment Grade Rating from both Rating Agencies and no Default has occurred and is continuing, the Partnership and its Restricted Subsidiaries
shall not be subject to Sections 4.08, 4.09, 4.11, 4.12, 4.16(a)(i) and 5.01(a)(iv) (collectively, the "Suspended Covenants"); provided, however, that the provisions set forth in
Sections 4.06, 4.10, 4.13, 4.14, 4.15, 4.17 and 4.18 shall not be so suspended; and provided, further, that if the Partnership and its Restricted Subsidiaries are not subject to the Suspended
Covenants for any period of time as a result of the preceding portion of this sentence and, subsequently, either of the Rating Agencies withdraws its ratings or downgrades the ratings assigned to the
Notes below the Investment Grade Ratings so that the Notes do not have an Investment Grade Rating from both Rating Agencies, or a Default (other than with respect to the Suspended Covenants) occurs
and is continuing, the Partnership and its Restricted Subsidiaries shall thereafter again be subject to the Suspended Covenants, subject to the terms, conditions and obligations set forth in this
Indenture (each such date of reinstatement being the "Reinstatement Date"). Compliance with the Suspended Covenants with respect to Restricted Payments 

51

 

made
after the Reinstatement Date shall be calculated in accordance with the terms of Section 4.08 as though such covenants had been in effect during the entire period of time from which the
Notes are issued. 

ARTICLE 5

SUCCESSORS  

Section 5.01.
Merger, Consolidation, or Sale of Assets. 

        (a)   Neither
of the Issuers may, directly or indirectly: (x) consolidate or merge with or into another Person (whether or not such Issuer is the survivor); or
(y) sell, assign, transfer, lease, convey or otherwise dispose of all or substantially all of its properties or assets, in one or more related transactions, to another Person; unless: 

        (i)    either:
(A) such Issuer is the surviving entity of such transaction; or (B) the Person formed by or surviving any such consolidation or merger (if other
than such Issuer) or to which such sale, assignment, transfer, lease, conveyance or other disposition shall have been made is an entity organized or existing under the laws of the United States, any
state thereof or the District of Columbia, provided that MarkWest Finance may not consolidate or merge with or into any entity other than a corporation satisfying such requirement for so long as the
Partnership remains a partnership; 

        (ii)   the
Person formed by or surviving any such consolidation or merger (if other than such Issuer) or the Person to which such sale, assignment, transfer, lease, conveyance
or other disposition shall have been made expressly assumes all the obligations of such Issuer under the Notes and this Indenture pursuant to agreements reasonably satisfactory to the Trustee; 

        (iii)  immediately
after such transaction no Default or Event of Default exists; 

        (iv)  in
the case of a transaction involving the Partnership and not MarkWest Finance, the Partnership or the Person formed by or surviving any such consolidation or merger
(if other than the Partnership) shall, on the date of such transaction after giving pro forma effect thereto and any related financing transactions as if the same had occurred at the beginning of the
applicable four-quarter period, be permitted to incur at least $1.00 of additional Indebtedness pursuant to the Fixed Charge Coverage Ratio test set forth in Section 4.09(a);
provided, however, that this clause (iv) shall be suspended during any period in which the Partnership and its Restricted Subsidiaries are not subject to the Suspended Covenants; and 

        (v)   such
Issuer has delivered to the Trustee an Officers' Certificate and an Opinion of Counsel, each stating that such consolidation, merger or disposition and, if a
supplemental indenture is required, such supplemental indenture comply with this Indenture and all conditions precedent therein relating to such transaction have been satisfied. 

        (b)   Notwithstanding
Section 5.01(a), the Partnership is permitted to reorganize as any other form of entity in accordance with the procedures established in this
Indenture; provided that: 

        (i)    the
reorganization involves the conversion (by merger, sale, contribution or exchange of assets or otherwise) of the Partnership into a form of entity other than a
limited partnership formed under Delaware law; 

        (ii)   the
entity so formed by or resulting from such reorganization is an entity organized or existing under the laws of the United States, any state thereof or the District
of Columbia; 

        (iii)  the
entity so formed by or resulting from such reorganization assumes all of the obligations of the Partnership under the Notes and this Indenture pursuant to
agreements reasonably satisfactory to the Trustee; 

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        (iv)  immediately
after such reorganization no Default or Event of Default exists; and 

        (v)   such
reorganization is not adverse to the Holders of the Notes (for purposes of this clause (v) it is stipulated that such reorganization shall not be
considered adverse to the Holders of the Notes solely because the successor or survivor of such reorganization (A) is subject to federal or state income taxation as an entity or (B) is
considered to be an "includible corporation" of an affiliated group of corporations within the meaning of Section 1504(b)(i) of the Code or any similar state or local law). 

        (c)   No
Subsidiary Guarantor may consolidate with or merge with or into (whether or not such Subsidiary Guarantor is the surviving Person) another Person, except the
Partnership or another Subsidiary Guarantor, unless (i) immediately after giving effect to such transaction, no Default or Event of Default exists, and (ii) the Person formed by or
surviving any such consolidation or merger assumes all the obligations of such Subsidiary Guarantor pursuant to the Subsidiary Guarantor's Guarantee of the Notes and this Indenture pursuant to a
supplemental indenture substantially in the form of Annex A hereto, except that no such assumption or supplemental indenture shall be required in those circumstances described in clauses
(i) and (ii) of Section 10.05 hereof. In case of any such consolidation or merger and upon the assumption by the successor Person by supplemental indenture, executed and delivered
to the Trustee substantially in the form of Annex A hereto, of the Guarantees contained herein and the due and punctual performance of all of the covenants of this Indenture to be performed by the
Subsidiary Guarantor, such successor shall succeed to and be substituted for the Subsidiary Guarantor with the same effect as if it had been named herein as a Subsidiary Guarantor. Such successor
thereupon may cause to be signed any or all of the notations of the Guarantees to be endorsed upon all of the Notes issuable hereunder which theretofore shall not have been signed by the Issuers and
delivered to the Trustee. All the Guarantees so issued shall in all respects have the same legal rank and benefit under this Indenture as the Guarantees theretofore and thereafter issued in accordance
with the terms of this Indenture as though all of such Guarantees had been issued at the date of the execution hereof. 

Section 5.02.
Successor Entity Substituted. 

        (a)   Upon
any consolidation or merger, or any sale, assignment, transfer, lease, conveyance or other disposition of all or substantially all of the properties or assets of an
Issuer in accordance with Section 5.01 hereof, the surviving entity formed by such consolidation or into or with which such Issuer is merged or to which such sale, assignment, transfer, lease,
conveyance or other disposition is made shall succeed to, and be substituted for (so that from and after the date of such consolidation, merger, sale, assignment, transfer, lease, conveyance or other
disposition, the provisions of this Indenture referring to the "Partnership" or "MarkWest Finance," as the case may be, shall refer instead to the surviving entity and not to the Partnership or
MarkWest Finance, as the case may be), and may exercise every right and power of the Partnership or MarkWest Finance, as the case may be, under this Indenture with the same effect as if such successor
Person had been named as an Issuer herein; and thereafter, if an Issuer is dissolved following a disposition of all or substantially all of its properties or assets in accordance with this Indenture,
it shall be discharged and released from all obligations and covenants under this Indenture and the Notes; provided, however, that the predecessor shall not be relieved from the obligation to pay the
principal of and interest on the Notes in the case of a lease of all or substantially all of its properties or assets. 

        (b)   If
the surviving entity shall have succeeded to and been substituted for an Issuer, such surviving entity may cause to be signed, and may issue either in its own name or
in the name of the applicable Issuer prior to such succession any or all of the Notes issuable hereunder which theretofore shall not have been signed by such Issuer and delivered to the Trustee; and,
upon the order of such surviving entity, instead of such Issuer, and subject to all the terms, conditions and limitations in this Indenture prescribed, the Trustee shall authenticate and shall deliver
any Notes which previously shall 

53

 

have
been signed and delivered by the Officers of such Issuer to the Trustee for authentication, and any Notes which such surviving entity thereafter shall cause to be signed and delivered to the
Trustee for that purpose (in each instance with notations of Guarantees thereon by the Subsidiary Guarantors). All of the Notes so issued and so endorsed shall in all respects have the same legal rank
and benefit under this Indenture as the Notes theretofore or thereafter issued and endorsed in accordance with the terms of this Indenture and the Guarantees as though all such Notes had been issued
and endorsed at the date of the execution hereof. 

        (c)   In
case of any such consolidation, merger, sale, assignment, transfer, lease, conveyance or other disposition, such changes in phraseology and form (but not in
substance) may be made in the Notes thereafter to be issued or the Guarantees to be endorsed thereon as may be appropriate. 

        (d)   For
all purposes of this Indenture and the Notes, Subsidiaries of any surviving entity (other than an Issuer) will, upon such transaction or series of transactions,
become Restricted Subsidiaries or Unrestricted Subsidiaries as provided pursuant to this Indenture and all Indebtedness, and all Liens on property or assets, of such surviving entity and its
Restricted Subsidiaries immediately prior to such transaction or series of transactions shall be deemed to have been incurred upon such transaction or series of transactions. 

ARTICLE 6

DEFAULTS AND REMEDIES  

Section 6.01.
Events of Default. 

        Each
of the following is an "Event of Default": 

        (a)   default
for 30 days in the payment when due of interest on, including Additional Interest with respect to, the Notes; 

        (b)   default
in payment when due of the principal of or premium, if any, on the Notes; 

        (c)   failure
by the Partnership to comply with the provisions described under Section 5.01 hereof; 

        (d)   failure
by the Partnership to comply with the provisions described under Section 3.09, 4.06, 4.07, 4.08, 4.09, 4.10, 4.11. 4.12, 4.13, 4.14, 4.15, 4.16, 4.17 or
4.18 hereof for 30 days after notice to the Issuers by the Trustee or to the Issuers and Trustee by Holders of at least 25% in aggregate principal amount of the Notes then outstanding (provided
that no such notice need be given, and an Event of Default shall occur, 30 days after a failure to comply with the covenants in Section 4.08 or 4.09 hereof, unless theretofore cured), in
each case other than a failure to purchase Notes which will constitute an Event of Default under clause (b) of this Section 6.01; 

        (e)   failure
by the Partnership to comply with any of its other agreements in this Indenture for 60 days after notice to the Issuers by the Trustee or to the Issuers
and Trustee by Holders of at least 25% in aggregate principal amount of the Notes then outstanding; 

        (f)    default
under any mortgage, indenture or instrument under which there may be issued or by which there may be secured or evidenced any Indebtedness for money borrowed by
either Issuer or any of the Restricted Subsidiaries of the Partnership (or the payment of which is guaranteed by either Issuer or any of such Restricted Subsidiaries), whether such Indebtedness or
guarantee now exists or is created after the date of this Indenture, if that default: 

        (i)    is
caused by a failure to pay principal of or premium, if any, or interest on such Indebtedness prior to the expiration of the grace period provided in such Indebtedness
on the date of such default (a "Payment Default"), or 

        (ii)   results
in the acceleration of such Indebtedness prior to its express maturity, 

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and,
in each case, the principal amount of any such Indebtedness, together with the principal amount of any other such Indebtedness under which there has been a Payment Default or the maturity of
which has been so accelerated, aggregates $10.0 million or more; 

        (g)   failure
by an Issuer or any Restricted Subsidiary of the Partnership to pay final judgments aggregating in excess of $10.0 million, which judgments are not paid,
discharged or stayed for a period of 60 days; 

        (h)   except
as permitted by this Indenture, any Guarantee shall be held in any judicial proceeding to be unenforceable or invalid or shall cease for any reason to be in full
force and effect or any Subsidiary Guarantor, or any Person acting on behalf of any Subsidiary Guarantor, shall deny or disaffirm its obligations under its Guarantee; 

        (i)    either
Issuer or any Restricted Subsidiary of the Partnership that is a Significant Subsidiary or any group of Restricted Subsidiaries of the Partnership that, taken as
a whole, would constitute a Significant Subsidiary, pursuant to or within the meaning of Bankruptcy Law: 

        (i)    commences
a voluntary case, 

        (ii)   consents
to the entry of an order for relief against it in an involuntary case, 

        (iii)  consents
to the appointment of a custodian of it or for all or substantially all of its property, 

        (iv)  makes
a general assignment for the benefit of its creditors, or 

        (v)   generally
is not paying its debts as they become due; and 

        (j)    a
court of competent jurisdiction enters an order or decree under any Bankruptcy Law that: 

        (i)    is
for relief against an Issuer or any Restricted Subsidiary of the Partnership that is a Significant Subsidiary or any group of Restricted Subsidiaries of the
Partnership that, taken as a whole, would constitute a Significant Subsidiary in an involuntary case; 

        (ii)   appoints
a custodian of an Issuer or any Restricted Subsidiary of the Partnership that is a Significant Subsidiary or any group of Restricted Subsidiaries of the
Partnership that, taken as a whole, would constitute a Significant Subsidiary or for all or substantially all of the property of an Issuer or any Restricted Subsidiary of the Partnership that is a
Significant Subsidiary or any group of Restricted Subsidiaries of the Partnership that, taken as a whole, would constitute a Significant Subsidiary; or 

        (iii)  orders
the liquidation of an Issuer or any Restricted Subsidiary of the Partnership that is a Significant Subsidiary or any group of Restricted Subsidiaries of the
Partnership that, taken as a whole, would constitute a Significant Subsidiary; 

and
the order or decree remains unstayed and in effect for 60 consecutive days. 

Section 6.02.
Acceleration. 

        If
any Event of Default (other than an Event of Default specified in clause (i) or (j) of Section 6.01 hereof) occurs and is continuing, the Trustee may, and upon
written request of the Holders of at least 25% in aggregate principal amount of the then outstanding Notes shall declare all the Notes to be due and payable immediately. Upon any such declaration, the
Notes shall become due and payable immediately. Notwithstanding the foregoing, if an Event of Default specified in clause (i) or (j) of Section 6.01 hereof occurs with
respect to an Issuer, all outstanding Notes shall be due and payable immediately without further action or notice. The Holders of a majority in aggregate principal amount of the then outstanding Notes
by written notice to the Trustee may on behalf of the Holders of all of the Notes rescind an acceleration and its consequences if the rescission would not 

55

 

conflict
with any judgment or decree and if all existing Events of Default (except nonpayment of principal, interest or premium that has become due solely because of the acceleration) have been cured
or waived. 

Section 6.03.
Other Remedies. 

        If
an Event of Default occurs and is continuing, the Trustee may pursue any available remedy to collect the payment of principal, premium, if any, and interest (including Additional
Interest, if any) on the Notes or to enforce the performance of any provision of the Notes or this Indenture. 

        The
Trustee may maintain a proceeding even if it does not possess any of the Notes or does not produce any of them in the proceeding. A delay or omission by the Trustee or any Holder of
a Note in exercising any right or remedy accruing upon an Event of Default shall not impair the right or remedy or constitute a waiver of or acquiescence in the Event of Default. All remedies
are cumulative to the extent permitted by law. 

Section 6.04.
Waiver of Past Defaults. 

        Holders
of not less than a majority in aggregate principal amount of the then outstanding Notes by notice to the Trustee may on behalf of the Holders of all of the Notes waive an
existing Default or Event of Default and its consequences hereunder, except a continuing Default or Event of Default in the payment of the principal of, premium and/or interest (including Additional
Interest, if any) on, the Notes (including in connection with an offer to purchase) (provided, however, that the Holders of a majority in aggregate principal amount of the then outstanding Notes may
rescind an acceleration and its consequences, including any related payment default that resulted from such acceleration). Upon any such waiver, such Default shall cease to exist, and any Event of
Default arising therefrom shall be deemed to have been cured for every purpose of this Indenture; but no such waiver shall extend to any subsequent or other Default or impair any right consequent
thereon. 

Section 6.05.
Control by Majority. 

        Holders
of a majority in aggregate principal amount of the then outstanding Notes may direct the time, method and place of conducting any proceeding for exercising any remedy available
to the Trustee or exercising any trust or power conferred on it. However, the Trustee may refuse to follow any direction that conflicts with law or this Indenture or that the Trustee determines may be
unduly prejudicial to the rights of other Holders of Notes or that may involve the Trustee in personal liability. 

Section 6.06.
Limitation on Suits. 

        A
Holder of a Note may pursue a remedy with respect to this Indenture or the Notes only if: 

        (a)   the
Holder of a Note gives to the Trustee written notice of a continuing Event of Default; 

        (b)   the
Holders of at least 25% in principal amount of the then outstanding Notes make a written request to the Trustee to pursue the remedy; 

        (c)   such
Holder of a Note or Holders of Notes offer and, if requested, provide to the Trustee indemnity or security satisfactory to the Trustee against any loss,
liability or expense; 

        (d)   the
Trustee does not comply with the request within 60 days after receipt of the request and the offer and, if requested, the provision of indemnity; and 

        (e)   during
such 60-day period the Holders of a majority in principal amount of the then outstanding Notes do not give the Trustee a direction inconsistent with
the request. 

        A
Holder of a Note may not use this Indenture to prejudice the rights of another Holder of a Note or to obtain a preference or priority over another Holder of a Note. 

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Section 6.07.
Rights of Holders of Notes to Receive Payment. 

        Notwithstanding
any other provision of this Indenture, the right of any Holder of a Note to receive payment of principal, premium and interest (including Additional Interest, if
any) on the Note, on or after the respective due dates expressed in the Note (including in connection with an offer to purchase), or to bring suit for the enforcement of any such payment on or
after such respective dates, shall not be impaired or affected without the consent of such Holder. 

Section 6.08.
Collection Suit by Trustee. 

        If
an Event of Default specified in Section 6.01(a) or (b) occurs and is continuing, the Trustee is authorized to recover a judgment in its own name and as trustee
of an express trust against the Issuers for the whole amount of principal of, premium and interest (including Additional Interest, if any) remaining unpaid on the Notes and interest on overdue
principal and, to the extent lawful, interest (including Additional Interest, if any) and such further amount as shall be sufficient to cover the costs and expenses of collection, including the
reasonable compensation, expenses, disbursements and advances of the Trustee, its agents and counsel. 

Section 6.09.
Trustee May File Proofs of Claim. 

        The
Trustee is authorized to file such proofs of claim and other papers or documents as may be necessary or advisable in order to have the claims of the Trustee (including any claim for
the reasonable compensation, expenses, disbursements and advances of the Trustee, its agents and counsel) and the Holders of the Notes allowed in any judicial proceedings relative to an Issuer or any
of the Subsidiary Guarantors (or any other obligor upon the Notes), its creditors or its property and shall be entitled and empowered to collect, receive and distribute any money or other property
payable or deliverable on any such claims and any custodian in any such judicial proceeding is hereby authorized by each Holder to make such payments to the Trustee, and in the event that the Trustee
shall consent to the making of such payments directly to the Holders, to pay to the Trustee any amount due to it for the reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel, and any other amounts due the Trustee under Section 7.07 hereof. To the extent that the payment of any such compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, and any other amounts due the Trustee under Section 7.07 hereof out of the estate in any such proceeding, shall be denied for any reason, payment of the same
shall be secured by a Lien on, and shall be paid out of, any and all distributions, dividends, money, securities and other properties that the Holders may be entitled to receive in such proceeding
whether in liquidation or under any plan of reorganization or arrangement or otherwise. Nothing herein contained shall be deemed to authorize the Trustee to authorize or consent to or accept or adopt
on behalf of any Holder any plan of reorganization, arrangement, adjustment or composition affecting the Notes or the rights of any Holder, or to authorize the Trustee to vote in respect of the claim
of any Holder in any such proceeding. 

Section 6.10.
Priorities. 

        If
the Trustee collects any money pursuant to this Article, it shall pay out the money in the following order: 

        First:
to the Trustee, its agents and attorneys for amounts due under Section 7.07 hereof, including payment of all compensation, expense and liabilities incurred, and all
advances made, by the Trustee and the costs and expenses of collection; 

        Second:
to Holders of Notes for amounts due and unpaid on the Notes for principal, premium and interest (including Additional Interest, if any), ratably, without preference or priority
of any kind, according to the amounts due and payable on the Notes for principal, premium and interest (including Additional Interest, if any), respectively; and 

57

 

        Third:
to the Issuers or the Subsidiary Guarantors or to such other party as a court of competent jurisdiction shall direct. 

        The
Trustee may fix a record date and payment date for any payment to Holders of Notes pursuant to this Section 6.10. 

Section 6.11.
Undertaking for Costs. 

        In
any suit for the enforcement of any right or remedy under this Indenture or in any suit against the Trustee for any action taken or omitted by it as a Trustee, a court in its
discretion may require the filing by any party litigant in the suit of an undertaking to pay the costs of the suit, and the court in its discretion may assess reasonable costs, including reasonable
attorneys' fees and expenses against any party litigant in the suit, having due regard to the merits and good faith of the claims or defenses made by the party litigant. This Section 6.11 does
not apply to a suit by the Trustee, a suit by a Holder of a Note pursuant to Section 6.07 hereof, or a suit by Holders of more than 10% in principal amount of the then outstanding Notes. 

ARTICLE 7

TRUSTEE  

Section 7.01.
Duties of Trustee. 

        (a)   If
an Event of Default has occurred and is continuing, the Trustee shall exercise such of the rights and powers vested in it by this Indenture, and use the same degree
of care and skill in its exercise, as a prudent man would exercise or use under the circumstances in the conduct of his own affairs. 

        (b)   Except
during the continuance of an Event of Default: 

        (i)    the
duties of the Trustee shall be determined solely by the express provisions of this Indenture and the Trustee need perform only those duties that are specifically set
forth in this Indenture and no others, and no implied covenants or obligations shall be read into this Indenture against the Trustee; and 

        (ii)   in
the absence of bad faith on its part, the Trustee may conclusively rely, as to the truth of the statements and the correctness of the opinions expressed therein,
upon certificates or opinions furnished to the Trustee and conforming to the requirements of this Indenture. However, in the case of any such certificates or opinions which by any provision hereof are
specifically required to be furnished to the Trustee, the Trustee shall be under a duty to examine the same to determine whether or not they conform to the requirements of this Indenture (but need not
confirm or investigate the accuracy of mathematical calculations or other facts stated therein). 

        (c)   The
Trustee may not be relieved from liabilities for its own negligent action, its own negligent failure to act, or its own willful misconduct, except that: 

        (i)    this
paragraph does not limit the effect of paragraph (b) of this Section; 

        (ii)   the
Trustee shall not be liable for any error of judgment made in good faith by a Responsible Officer, unless it is proved that the Trustee was negligent in
ascertaining the pertinent facts; and 

        (iii)  the
Trustee shall not be liable with respect to any action it takes or omits to take in good faith in accordance with a direction received by it pursuant to any
provision of this Indenture relating to the time, method and place of conducting any proceeding or remedy available to the Trustee, or exercising any trust or power conferred upon the Trustee under
this Indenture. 

58

   
        (d)   Whether or not therein expressly so provided, every provision of this Indenture that in any way relates to the Trustee is subject to paragraphs (a), (b), and
(c) of this Section. 

        (e)   No
provision of this Indenture shall require the Trustee to expend or risk its own funds or otherwise incur any financial liability. The Trustee shall be under no
obligation to exercise any of its rights and powers under this Indenture at the request of any Holders, unless such Holder shall have offered to the Trustee security or indemnity satisfactory to it
against any claim, loss, liability or expense. 

        (f)    The
Trustee shall not be liable for interest on any money received by it except as the Trustee may agree in writing with the Partnership or MarkWest Finance. Money held
in trust by the Trustee need not be segregated from other funds except to the extent required by law. 

Section 7.02.
Rights of Trustee. 

        (a)   Subject
to the provisions of Section 7.01(a) hereof, the Trustee may conclusively rely upon any document believed by it to be genuine and to have been
signed or presented by the proper Person. The Trustee need not investigate any fact or matter stated in the document, but may accept the same as conclusive evidence of the truth and accuracy of such
statement or the correctness of such opinion. 

        (b)   Before
the Trustee acts or refrains from acting in the administration of this Indenture, it may require an Officers' Certificate or an Opinion of Counsel or both. The
Trustee shall not be liable for any action it takes or omits to take in good faith in reliance on such Officers' Certificate or Opinion of Counsel. The Trustee may consult with counsel of its
selection and the advice of such counsel or any Opinion of Counsel shall be full and complete authorization and protection from liability in respect of any action taken, suffered or omitted by it
hereunder in good faith and in reliance thereon. 

        (c)   The
Trustee may execute any of its trusts or powers or perform any duties under this Indenture either directly by or through agents or attorneys, and may in all cases
pay, subject to reimbursement as provided herein, such reasonable compensation as it deems proper to all such agents and attorneys employed or retained by it, and the Trustee shall not be responsible
for any misconduct or negligence of any agent or attorney appointed with due care. 

        (d)   The
Trustee shall not be liable for any action it takes or omits to take in good faith that it believes to be authorized or within the rights or powers conferred upon it
by this Indenture. 

        (e)   Unless
otherwise specifically provided in this Indenture, any demand, request, direction or notice from an Issuer or any Subsidiary Guarantor shall be sufficient if
signed by an Officer of the Partnership or the General Partner (in the case of the Partnership), by an Officer of the General Partner (in the case of the General Partner) or by an Officer of MarkWest
Finance or any Subsidiary Guarantor (in the case of MarkWest Finance or such Subsidiary Guarantor). 

        (f)    The
Trustee shall be under no obligation to exercise any of the rights or powers vested in it by this Indenture at the request or direction of any of the Holders unless
such Holders shall have offered to the Trustee reasonable security or indemnity against the claims, costs, expenses and liabilities that might be incurred by it in compliance with such request or
direction. 

        (g)   The
Trustee is not required to make any inquiry or investigation into facts or matters stated in any document but the Trustee, in its discretion, may make such further
inquiry or investigation into such facts or matters as it may see fit and, if the Trustee determines to make such further inquiry or investigation, it shall be entitled to examine the books, records
and premises of the Issuers. 

        (h)   The
Trustee is not required to take notice or shall not be deemed to have notice of any Default or Event of Default hereunder except Defaults or Events of Default under
Sections 6.01(a) and 6.01(b) hereof, unless a Responsible Officer of the Trustee has actual knowledge thereof or has received notice in writing of such Default or Event of Default
from the Issuers or the Holders of at 

59

 

least
25% in aggregate principal amount of the Notes then outstanding, and in the absence of any such notice, the Trustee may conclusively assume that no such Default or Event of Default exists. 

        (i)    The
Trustee is not required to give any bond or surety with respect to the performance of its duties or the exercise of its powers under this Indenture. 

        (j)    Under
no circumstances shall the Trustee be liable in its individual capacity for the obligations evidenced by the Notes. 

        (k)   In
the event the Trustee receives inconsistent or conflicting requests and indemnity from two or more groups of Holders of Notes, each representing less than the
aggregate principal amount of Notes outstanding required to take any action hereunder, the Trustee, in its sole discretion may determine what action, if any, shall be taken. 

        (l)    The
Trustee's immunities and protections from liability and its right to indemnification in connection with the performance of its duties under this Indenture shall
extend to the Trustee's officers, directors, agents, attorneys and employees. Such immunities and protections and right to indemnification, together with the Trustee's right to compensation, shall
survive the Trustee's resignation of removal, the discharge of this Indenture and final payments of the Notes. 

        (m)  The
permissive right of the Trustee to take actions permitted by this Indenture shall not be construed as an obligation or duty to do so. 

        (n)   Except
for information provided by the Trustee concerning the Trustee, the Trustee shall have no responsibility for any information and any offering memorandum,
disclosure material or prospectus distributed with respect to the Notes. 

        (o)   The
Trustee shall not be liable for any action taken or omitted by it in good faith at the direction of the Holders of not less than a majority in aggregate principal
amount of the Notes as to the time, method, and place of conducting any proceedings for any remedy available to the Trustee or the exercising of any power conferred by this Indenture. 

        (p)   Subject
to Section 7.01(d), whether or not therein expressly so provided, every provision of this Indenture relating to the conduct of, or affecting the liability
of, or affording protection to the Trustee shall be subject to the provisions of this Section 7.02. 

        (q)   Any
action taken, or omitted to be taken, by the Trustee in good faith, pursuant to this Indenture upon the request or authority or consent of any Person who, at the
time of making such request or giving such authority or consent, is the Holder of any Note shall be conclusive and binding upon all future Holders of that Note and upon securities
executed and delivered in exchange therefore or in place thereof. 

Section 7.03.
Individual Rights of Trustee. 

        The
Trustee in its commercial banking or any other capacity may become the owner or pledgee of Notes and may otherwise deal with the Issuers, any Subsidiary Guarantors or any Affiliate
of the Partnership with the same rights it would have if it were not Trustee. Any Affiliate of the Trustee or
Agent may do the same with like rights and duties. However, in the event that the Trustee acquires any conflicting interest (as defined in the TIA) after a Default has occurred and is continuing it
must eliminate such conflict within 90 days, apply to the SEC for permission to continue as trustee or resign. The Trustee is also subject to Sections 7.10 and 7.11 hereof. 

Section 7.04.
Trustee's Disclaimer. 

        The
Trustee shall not be responsible for and makes no representation as to the validity or adequacy of this Indenture, the Notes or the Guarantees, it shall not be accountable for the
Issuers' use of the proceeds from the Notes or any money paid to an Issuer or upon an Issuer's direction under 

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any
provision of this Indenture, it shall not be responsible for the use or application of any money received by any Paying Agent other than the Trustee, and it shall not be responsible for any
statement or recital herein or any statement in the Notes or any other document in connection with the sale of the Notes or pursuant to this Indenture other than its certificate of authentication. 

Section 7.05.
Notice of Defaults. 

        If
a Default or Event of Default known to the Trustee occurs, the Trustee shall mail to Holders of Notes a notice of the Default or Event of Default within 90 days after it
occurs. Except in the case of a Default or Event of Default in payment of principal of, premium, if any, or interest (including Additional Interest, if any) on any Note, the Trustee may withhold the
notice if and so long as a committee of its Responsible Officers in good faith determines that withholding the notice is in the interests of the Holders of the Notes. 

Section 7.06.
Reports by Trustee to Holders of the Notes. 

        Within
60 days after each May 15 beginning with the May 15 following the date of this Indenture, and for so long as Notes remain outstanding, the Trustee shall mail
to the Holders of the Notes a brief report dated as of such reporting date that complies with TIA Section 313(a) (but if no event described in TIA Section 313(a) has
occurred within the twelve months preceding the reporting date, no report need be transmitted). The Trustee also shall comply with TIA Section 313(b)(2). The Trustee shall also transmit
by mail all reports as required by TIA Section 313(c). 

        A
copy of each report at the time of its mailing to the Holders of Notes shall be mailed to the Partnership and filed with the SEC and each stock exchange on which the Notes are listed
in
accordance with TIA Section 313(d). The Issuers shall promptly notify the Trustee when the Notes are listed on any stock exchange. 

Section 7.07.
Compensation and Indemnity. 

        The
Issuers and the Subsidiary Guarantors shall pay to the Trustee from time to time such compensation as shall be agreed upon in writing between the Issuers and the Trustee for its
acceptance of this Indenture and services hereunder. The Trustee's compensation shall not be limited by any law on compensation of a trustee of an express trust. The Issuers and the Subsidiary
Guarantors shall reimburse the Trustee promptly upon request for all reasonable disbursements, advances and expenses incurred or made by it in addition to the compensation for its services. Such
expenses shall include the reasonable compensation, disbursements and expenses of the Trustee's agents and counsel. 

        The
Issuers and the Subsidiary Guarantors shall indemnify each of the Trustee or any successor Trustee against any and all losses, damages, claims, liabilities or expenses (including
reasonable attorneys' fees and expenses) incurred by it arising out of or in connection with the acceptance or administration of its duties under this Indenture, including the costs and expenses of
enforcing this Indenture against either of the Issuers or any Subsidiary Guarantor (including this Section 7.07) and defending itself against any claim (whether asserted by an Issuer, any
Subsidiary Guarantor, or any Holder or any other Person) or liability in connection with the exercise or performance of any of its powers or duties hereunder, except to the extent any such loss,
liability or expense may be attributable to its negligence or bad faith. The Trustee shall notify the Issuers promptly of any claim for which it may seek indemnity. Failure by the Trustee to so notify
the Issuers shall not relieve the Issuers and the Subsidiary Guarantors of their obligations hereunder. The Issuers and the Subsidiary Guarantors shall defend the claim and the Trustee shall cooperate
in the defense. The Trustee may have separate counsel and the Issuers and the Subsidiary Guarantors shall pay the reasonable fees and expenses of such separate counsel; provided that the Issuers and
the Subsidiary Guarantors will not be required to pay such fees and expenses if they assume the Trustee's defense with counsel acceptable to and approved by the Trustee (such approval not to be
unreasonably withheld) and there is no conflict of interest between the Issuers and the Trustee in connection with such defense. The Issuers and the 

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Subsidiary
Guarantors need not pay for any settlement made without their consent, which consent shall not be unreasonably withheld. Neither the Issuers nor the Subsidiary Guarantors need reimburse the
Trustee for any expense or indemnity against any liability or loss of the Trustee to the extent such expense, liability or loss is attributable to the negligence or bad faith of the Trustee. 

        The
obligations of the Issuers and the Subsidiary Guarantors under this Section 7.07 shall survive the satisfaction and discharge of this Indenture. 

        To
secure the Issuers' and the Subsidiary Guarantors' payment obligations in this Section, the Trustee shall have a Lien (which it may exercise through right of set-off)
prior to the Notes on all money or property held or collected by the Trustee, except that held in trust to pay principal, premium, if any, and interest (including Additional Interest, if any) on
particular Notes. Such Lien shall survive the satisfaction and discharge of this Indenture. When the Trustee incurs expenses or renders services after an Event of Default specified in
Section 6.01(i) or (j) hereof occurs, the expenses and the compensation for the services (including the fees and expenses of its agents and counsel) are intended to constitute
expenses of administration under any Bankruptcy Law. 

        The
Trustee shall comply with the provisions of TIA Section 313(b)(2) to the extent applicable. 

Section 7.08.
Replacement of Trustee. 

        A
resignation or removal of the Trustee and appointment of a successor Trustee shall become effective only upon the successor Trustee's acceptance of appointment as provided in this
Section. The Trustee may resign in writing at any time and be discharged from the trust hereby created by so notifying the Issuers. The Holders of Notes of a majority in principal amount of the then
outstanding Notes may remove the Trustee by so notifying the Trustee and the Issuers in writing. The Issuers may remove the Trustee if: 

        (a)   the
Trustee fails to comply with Section 7.10 hereof; 

        (b)   the
Trustee is adjudged a bankrupt or an insolvent or an order for relief is entered with respect to the Trustee under any Bankruptcy Law; 

        (c)   a
custodian or public officer takes charge of the Trustee or its property; or 

        (d)   the
Trustee becomes incapable of acting. 

        If
the Trustee resigns or is removed or if a vacancy exists in the office of Trustee for any reason, the Issuers shall promptly appoint a successor Trustee. Within one year after the
successor Trustee takes office, the Holders of a majority in aggregate principal amount of the then outstanding Notes may appoint a successor Trustee to replace the successor Trustee appointed by the
Issuers. 

        If
a successor Trustee does not take office within 60 days after the retiring Trustee resigns or is removed, the retiring Trustee, the Issuers, any Subsidiary Guarantor or the
Holders of Notes of at least
10% in aggregate principal amount of the then outstanding Notes may petition any court of competent jurisdiction for the appointment of a successor Trustee. 

        If
the Trustee, after written request by any Holder of a Note who has been a Holder of a Note for at least six months, fails to comply with Section 7.10, such
Holder of a Note may petition any court of competent jurisdiction for the removal of the Trustee and the appointment of a successor Trustee. 

        A
successor Trustee shall deliver a written acceptance of its appointment to the retiring Trustee and to the Issuers. Thereupon, the resignation or removal of the retiring Trustee shall
become effective, and the successor Trustee shall have all the rights, powers and duties of the Trustee under this Indenture. The successor Trustee shall mail a notice of its succession to Holders of
the Notes. The retiring Trustee shall promptly transfer all property held by it as Trustee to the successor Trustee, provided all sums owing to the Trustee hereunder have been paid and subject to the
Lien provided for 

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in
Section 7.07 hereof. Notwithstanding replacement of the Trustee pursuant to this Section 7.08, the Issuers' and the Subsidiary Guarantors' obligations under Section 7.07 hereof
shall continue for the benefit of the retiring Trustee. 

Section 7.09.
Successor Trustee by Merger, Etc. 

        If
the Trustee consolidates, merges or converts into, or transfers all or substantially all of its corporate trust business to, another corporation, the successor corporation without any
further act shall be the successor Trustee. As soon as practicable, the successor Trustee shall mail a notice of its succession to the Issuers and the Holders of the Notes. 

Section 7.10.
Eligibility; Disqualification. 

        There
shall at all times be a Trustee hereunder that is a corporation organized and doing business under the laws of the United States of America or of any state thereof that is
authorized under such laws to exercise corporate trust powers, that is subject to supervision or examination by federal or state authorities and that has a combined capital and surplus of at least
$50 million as set forth in its most recent published annual report of condition. 

        This
Indenture shall always have a Trustee who satisfies the requirements of TIA Section 310(a)(1), (2) and (5). The Trustee is subject to TIA Section 310(b),
provided, however, that there shall be excluded from the operation of TIA Section 310(b)(l) any indenture or indentures under which other
securities or certificates of interest or participation in other securities of the Issuers are outstanding if the requirements of such exclusion set forth in TIA Section 310(b)(l) are met. For
purposes of the preceding sentence, the optional provision permitted by the second sentence of Section 310(b)(9) of the Trust Indenture Act shall be applicable. 

Section 7.11.
Preferential Collection of Claims Against Issuers. 

        The
Trustee is subject to TIA Section 311(a), excluding any creditor relationship listed in TIA Section 311(b). A Trustee who has resigned or been removed shall be subject
to TIA Section 311(a) to the extent indicated therein. 

ARTICLE 8

LEGAL DEFEASANCE AND COVENANT DEFEASANCE  

Section 8.01.
Option to Effect Legal Defeasance or Covenant Defeasance. 

        The
Issuers may, at the option of the Board of Directors of the General Partner (in the case of the Partnership) or of the Board of Directors of MarkWest Finance (in the case of MarkWest
Finance) evidenced by a resolution set forth in an Officers' Certificate, at any time, elect to have either Section 8.02 or 8.03 hereof be applied to all outstanding Notes upon compliance with
the conditions set forth below in this Article 8. 

Section 8.02.
Legal Defeasance and Discharge. 

        Upon
the Issuers' exercise under Section 8.01 hereof of the option applicable to this Section 8.02, the Issuers and the Subsidiary Guarantors shall, subject to the
satisfaction of the conditions set forth in Section 8.04 hereof, be deemed to have been discharged from their respective Obligations and certain other obligations with respect to all
outstanding Notes and Guarantees, as applicable, on the date the conditions set forth below are satisfied (hereinafter, "Legal Defeasance"). For this purpose, Legal Defeasance means that the Issuers
and the Subsidiary Guarantors shall be deemed to have paid and discharged the entire Indebtedness represented by the outstanding Notes, which shall thereafter be deemed to be "outstanding" only for
the purposes of Section 8.05 hereof and the other Sections of this Indenture referred to in clauses (a) and (b) of this sentence below, and to have satisfied all its other
obligations under such Notes and this Indenture (and the Trustee, on demand of and at the expense of 

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the
Issuers, shall execute proper instruments acknowledging the same), except for the following provisions which shall survive until otherwise terminated or discharged hereunder: (a) the rights
of Holders of outstanding Notes to receive solely from the trust fund described in Section 8.04 hereof, and as more fully set forth in such Section, payments in respect of the principal of,
premium, if any, and interest (including Additional Interest, if any) on, such Notes when such payments are due, (b) the Issuers' obligations with respect to such Notes under
Sections 2.03, 2.04, 2.06, 2.07, 2.10 and 4.02 hereof, (c) the rights, powers, trusts, duties and immunities of the Trustee hereunder and the Issuers' and the Subsidiary Guarantors'
obligations in connection therewith and (d) this Article 8. Subject to compliance with this Article 8, the Issuers may exercise the option under this Section 8.02
notwithstanding the prior exercise of its option under Section 8.03 hereof. 

Section 8.03.
Covenant Defeasance. 

        Upon
the Issuers' exercise under Section 8.01 hereof of the option applicable to this Section 8.03, the Issuers and the Subsidiary Guarantors shall, subject to the
satisfaction of the conditions set forth in Section 8.04 hereof, be released from their obligations under the covenants contained in Sections 3.09, 4.04, 4.06, 4.07, 4.08, 4.09, 4.10, 4.11,
4.12, 4.13, 4.14, 4.15, 4.16, 4.18 and 5.01(a)(iv) hereof and any covenant added to this Indenture subsequent to the Issue Date pursuant to Section 9.01 hereof with respect to the
outstanding Notes on and after the date the conditions set forth below are satisfied (hereinafter, "Covenant Defeasance"), and the Notes shall thereafter be deemed not "outstanding" for the purposes
of any direction, waiver, consent or declaration or act of Holders (and the consequences of any thereof) in connection with such covenants, but shall continue to be deemed "outstanding" for all other
purposes hereunder (it being understood that such Notes shall not be deemed outstanding for accounting purposes). For this purpose, Covenant Defeasance means that, with respect to the outstanding
Notes, the Issuers may omit to comply with and shall have no liability in respect of any term, condition or limitation set forth in any such covenant, whether directly or indirectly, by reason of any
reference elsewhere herein to any such covenant or by reason of any reference in any such covenant to any other provision herein or in any other document and such omission to comply shall not
constitute a Default or an Event of Default under Section 6.01 hereof, but, except as specified above, the remainder of this Indenture and such Notes shall be unaffected thereby. In addition,
upon the Issuers' exercise under Section 8.01 hereof of the option applicable to this Section 8.03 hereof, subject to the satisfaction of the conditions set forth in Section 8.04
hereof, Sections 6.01(d) through 6.01(h) hereof shall not constitute Events of Default. 

Section 8.04.
Conditions to Legal Defeasance or Covenant Defeasance. 

        The
following shall be the conditions to the application of either Section 8.02 or 8.03 hereof to the outstanding Notes: 

        In
order to exercise either Legal Defeasance or Covenant Defeasance: 

        (a)   the
Issuers must irrevocably deposit with the Trustee, in trust, for the benefit of the Holders, cash in United States dollars, U.S. Government Obligations, or a
combination thereof, in such amounts as shall be sufficient, in the opinion of a nationally recognized firm of independent public accountants, to pay the principal of, premium, if any, and interest,
on the outstanding Notes at the Stated Maturity thereof or on the applicable redemption date, as the case may be, and the Issuers must specify whether the Notes are being defeased to Stated Maturity
or to a particular redemption date; 

        (b)   in
the case of an election under Section 8.02 hereof, the Issuers shall have delivered to the Trustee an Opinion of Counsel reasonably acceptable to the Trustee
confirming that (i) the Partnership has received from, or there has been published by, the Internal Revenue Service a ruling or (ii) since the Issue Date, there has been a change in the
applicable federal income tax law, in either case to the effect that, and based thereon such Opinion of Counsel shall confirm that, the Holders of the outstanding Notes will not recognize income, gain
or loss for federal income tax purposes as a result of 

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such
Legal Defeasance and will be subject to federal income tax on the same amounts, in the same manner and at the same times as would have been the case if such Legal Defeasance had not occurred; 

        (c)   in
the case of an election under Section 8.03 hereof, the Issuers shall have delivered to the Trustee an Opinion of Counsel reasonably acceptable to the Trustee
confirming that the Holders of the outstanding Notes will not recognize income, gain or loss for federal income tax purposes as a result of such Covenant Defeasance and will be subject to federal
income tax on the same amounts, in the same manner and at the same times as would have been the case if such Covenant Defeasance had not occurred; 

        (d)   no
Default or Event of Default shall have occurred and be continuing either (i) on the date of such deposit (other than a Default or Event of Default resulting
from the incurrence of Indebtedness all or a portion of the proceeds of which shall be applied to such deposit) or (ii) insofar as Sections 6.01(i) and 6.01(j) hereof are
concerned, at any time in the period ending on the 91st day after the date of deposit; 

        (e)   such
Legal Defeasance or Covenant Defeasance shall not result in a breach or violation of, or constitute a default under, any material agreement or instrument (other
than this Indenture) to which the Partnership or any of its Subsidiaries is a party or by which the Partnership or any of its Subsidiaries is bound; 

        (f)    the
Issuers shall have delivered to the Trustee an Opinion of Counsel to the effect that after the 91st day following the deposit, the trust funds will not be subject to
the effect of any applicable bankruptcy, insolvency, reorganization or similar laws affecting creditors' rights generally; 

        (g)   the
Issuers shall have delivered to the Trustee an Officers' Certificate stating that the deposit was not made by the Issuers with the intent of preferring the Holders
over any other creditors of the Issuers or the Subsidiary Guarantors or with the intent of defeating, hindering, delaying or defrauding other creditors of the Issuers; and 

        (h)   the
Issuers shall have delivered to the Trustee an Officers' Certificate and an Opinion of Counsel, each stating that all conditions precedent provided for or relating
to the Legal Defeasance or the Covenant Defeasance have been complied with. 

Section 8.05.
Deposited Money and Government Securities to be Held in Trust, Other Miscellaneous Provisions. 

        Subject
to Section 11.03 hereof, all money and U.S. Government Obligations (including the proceeds thereof) deposited with the Trustee (or other qualifying trustee, collectively
for purposes of this Section 8.05, the "Trustee") pursuant to Section 8.04 hereof in respect of the outstanding Notes shall be held in trust and applied by the Trustee, in accordance
with the provisions of such Notes and this Indenture, to the payment, either directly or through any Paying Agent (including either Issuer acting as a Paying Agent) as the Trustee may determine, to
the Holders of such Notes of all sums due and to become due thereon in respect of principal, premium, if any, and interest (including Additional Interest, if any), but such money need not be
segregated from other funds except to the extent required by law. 

        The
Issuers and the Subsidiary Guarantors shall pay and indemnify the Trustee against any tax, fee or other charge imposed on or assessed against the cash or non-callable
U.S. Government Obligations deposited pursuant to Section 8.04 hereof or the principal and interest received in respect thereof other than any such tax, fee or other charge which by law is for
the account of the Holders of the outstanding Notes. 

        Anything
in this Article 8 to the contrary notwithstanding, the Trustee shall deliver or pay to the Issuers from time to time upon the request of the Issuers any money or
non-callable U.S. Government Obligations held by it as provided in Section 8.04 hereof which, in the opinion of a nationally 

65

 

recognized
firm of independent public accountants expressed in a written certification thereof delivered to the Trustee (which may be the opinion delivered under Section 8.04(a) hereof),
are in excess of the amount thereof that would then be required to be deposited to effect an equivalent Legal Defeasance or Covenant Defeasance. 

        If
the Issuers exercise either their Legal Defeasance or Covenant Defeasance option, each Subsidiary Guarantor shall be released and relieved of any obligations under its Guarantee and
any security for the Notes (other than the trust fund described in Section 8.04 hereof) shall be released. 

Section 8.06.
[Intentionally omitted]. 

Section 8.07.
Reinstatement. 

        If
the Trustee or Paying Agent is unable to apply any United States dollars or U.S. Government Obligations in accordance with Section 8.02 or 8.03 hereof, as the case may be, by
reason of any legal proceeding or by reason of any order or judgment of any court or governmental authority enjoining, restraining or otherwise prohibiting such application, then the Issuers' and the
Subsidiary Guarantors' Obligations under this Indenture, the Notes and the Guarantees, as applicable, shall be revived and reinstated as though no deposit had occurred pursuant to Section 8.02
or 8.03 hereof until such time as the Trustee or Paying Agent is permitted to apply all such money or U.S. Government Obligations in accordance with Section 8.02 or 8.03 hereof, as the case may
be; provided, however, that, if the Issuers or the Subsidiary Guarantors make any payment of principal of, premium, if any, or interest (including any Additional Interest, if any) on any
Note following the reinstatement of its Obligations, the Issuers and the Subsidiary Guarantors shall be subrogated to the rights of the Holders of such Notes to receive such payment from the
money or U.S. Government Obligations held by the Trustee or Paying Agent. 

ARTICLE 9

AMENDMENT, SUPPLEMENT AND WAIVER  

Section 9.01.
Without Consent of Holders of Notes. 

        Notwithstanding
Section 9.02 of this Indenture, the Issuers and the Subsidiary Guarantors and the Trustee may amend or supplement this Indenture, the Guarantees, or the Notes
without the consent of any Holder of a Note: 

        (a)   to
cure any ambiguity, defect or inconsistency; 

        (b)   to
provide for uncertificated Notes in addition to or in place of certificated Notes; 

        (c)   to
provide for the assumption of an Issuer's or a Subsidiary Guarantor's obligations to the Holders of the Notes in the case of a merger or consolidation or sale of all
or substantially all of such Issuer's assets pursuant to Article 5 hereof; 

        (d)   to
add or release Subsidiary Guarantors pursuant to the terms of this Indenture; 

        (e)   to
make any change that would provide any additional rights or benefits to the Holders of the Notes or surrender any right or power conferred upon the Issuers or the
Subsidiary Guarantors by this Indenture that does not adversely affect the rights hereunder of any Holder of the Notes, provided that any change to conform this Indenture to the Offering Memorandum
shall not be deemed to adversely affect such rights; 

        (f)    to
provide for the issuance of additional Notes in accordance with the limitations set forth in this Indenture; 

        (g)   to
comply with requirements of the SEC in order to effect or maintain the qualification of this Indenture under the TIA; 

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        (h)   to
evidence or provide for the acceptance of appointment under this Indenture of a successor Trustee; 

        (i)    to
add any additional Events of Default; or 

        (j)    to
secure the Notes and/or the Guarantees. 

        Upon
the request of the Issuers accompanied by a resolution of the Board of Directors of the General Partner (in the case of the Partnership), and of the Board of Directors of MarkWest
Finance and each of the Subsidiary Guarantors (in the case of MarkWest Finance and the Subsidiary Guarantors), authorizing the execution of any such amended or supplemental Indenture, and upon receipt
by the Trustee of the documents described in Section 9.06 hereof, the Trustee shall join with the Issuers and each of the Subsidiary Guarantors in the execution of any amended or supplemental
indenture authorized or permitted by the terms of this Indenture and to make any further appropriate agreements and stipulations that may be therein contained, but the Trustee shall not be obligated
to enter into such amended or supplemental indenture that affects its own rights, duties or immunities under this Indenture or otherwise. 

Section 9.02.
With Consent of Holders of Notes. 

        Except
as provided below in this Section 9.02, the Issuers, the Subsidiary Guarantors and the Trustee may amend or supplement this Indenture (including Sections 3.09, 4.06
and 4.07 hereof), the Guarantees, and the Notes with the consent of the Holders of at least a majority in principal amount of the Notes then outstanding (including, without limitation, consents
obtained in connection with a purchase of, or tender offer or exchange offer for, the Notes), and, subject to Sections 6.04 and 6.07 hereof, any existing Default or Event of Default or
compliance with any provision of this Indenture, the Guarantees or the Notes may be waived with the consent of the Holders of a majority in principal amount of the then outstanding Notes (including
consents obtained in connection with a tender offer or exchange offer for the Notes). 

        Upon
the request of the Issuers accompanied by a resolution of the Board of Directors of the General Partner (in the case of the Partnership) and of the Board of Directors of MarkWest
Finance and each of the Subsidiary Guarantors (in the case of MarkWest Finance and each of the Subsidiary Guarantors) authorizing the execution of any such amended or supplemental indenture, and upon
the filing with the Trustee of evidence satisfactory to the Trustee of the consent of the Holders of Notes as aforesaid, and upon receipt by the Trustee of the documents described in
Section 9.06 hereof, the Trustee shall join with the Issuers and each of the Subsidiary Guarantors in the execution of such amended or supplemental indenture unless such amended or supplemental
Indenture affects the Trustee's own rights, duties or immunities under this Indenture or otherwise, in which case the Trustee may in its discretion, but shall not be obligated to, enter into such
amended or supplemental indenture. 

        It
shall not be necessary for the consent of the Holders of Notes under this Section 9.02 to approve the particular form of any proposed amendment, supplement or waiver, but it
shall be sufficient if such consent approves the substance thereof. 

        After
an amendment, supplement or waiver under this Section becomes effective, the Issuers shall mail to the Holders of Notes affected thereby a notice briefly describing the
amendment, supplement or waiver. Any failure of the Issuers to mail such notice, or any defect therein, shall not, however, in any way impair or affect the validity of any such amended or supplemental
Indenture or waiver. Subject to Sections 6.04 and 6.07 hereof, the Holders of a majority in aggregate principal amount of the Notes then outstanding may waive compliance in a particular
instance by the Issuers with any provision of this 

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Indenture
or the Notes. However, without the consent of each Holder affected, an amendment, supplement or waiver may not (with respect to any Notes held by a non-consenting Holder): 

        (a)   reduce
the principal amount of Notes whose Holders must consent to an amendment, supplement or waiver; 

        (b)   reduce
the principal of or change the fixed maturity of any Note or alter or waive any of the provisions with respect to the redemption or repurchase of the
Notes, except as provided above with respect to Sections 3.09, 4.06 and 4.07 hereof; 

        (c)   reduce
the rate of or change the time for payment of interest, including default interest, on any Note; 

        (d)   waive
a Default or Event of Default in the payment of principal of or premium, if any, or interest (including Additional Interest, if any) on the Notes (except a
rescission of acceleration of the Notes by the Holders of at least a majority in aggregate principal amount of the then outstanding Notes and a waiver of the payment default that resulted from such
acceleration); 

        (e)   make
any Note payable in money other than that stated in the Notes; 

        (f)    make
any change in the provisions of this Indenture relating to waivers of past Defaults or the rights of Holders of Notes to receive payments of principal of or
premium, if any, or interest on the Notes (other than as permitted by clause (g) below); 

        (g)   waive
a redemption or repurchase payment with respect to any Note (other than a payment required by the covenants contained in Sections 3.09, 4.06 and 4.07
hereof); 

        (h)   except
as otherwise permitted by this Indenture, release any Subsidiary Guarantor from any of its Obligations under its Guarantee or this Indenture, or change any
Guarantee in any manner that would adversely affect the right of Holders; or 

        (i)    make
any change in Section 6.04 or 6.07 hereof or in the foregoing amendment, supplement and waiver provisions (except to increase any percentage set forth
therein). 

Section 9.03.
Compliance with Trust Indenture Act. 

        Every
amendment or supplement to this Indenture, the Guarantees, or the Notes shall be set forth in an amended or supplemental Indenture that complies with the TIA as then in effect. 

Section 9.04.
Revocation and Effect of Consents. 

        Until
an amendment, supplement or waiver becomes effective, a consent to it by a Holder of a Note is a continuing consent by the Holder of a Note and every subsequent
Holder of a Note or portion of a Note that evidences the same debt as the consenting Holder's Note, even if notation of the consent is not made on any Note. However, any such Holder of a
Note or subsequent Holder of a Note may revoke the consent as to its Note if the Trustee receives written notice of revocation before the date the waiver, supplement or amendment
becomes effective. An amendment, supplement or waiver becomes effective in accordance with its terms and thereafter binds every Holder. 

        The
Issuers may, but shall not be obligated to, fix a record date for the purpose of determining the Holders entitled to consent to any amendment, supplement or waiver. If a record date
is fixed, then notwithstanding the last sentence of the immediately preceding paragraph, those Persons who were Holders at such record date (or their duly designated proxies), and only those Persons,
shall be entitled to consent to such amendment, supplement or waiver or revoke any consent previously given, whether or not such Persons continue to be Holders after such record date. No consent shall
be valid or effective for more than 90 days after such record date except to the extent that the requisite number of consents to the amendment, supplement or waiver have been obtained within
such 90-day period or as set forth in the next paragraph of this Section 9.04. 

68

 

        After
an amendment, supplement or waiver becomes effective, it shall bind every Holder, unless it makes a change described in any of clauses (a) through (i) of
Section 9.02, in which case, the amendment, supplement or waiver shall bind only each Holder of a Note who has consented to it and every subsequent Holder of a Note or portion of
a Note that evidences the same indebtedness as the consenting Holder's Note. 

Section 9.05.
Notation or Exchange of Notes. 

        The
Trustee may place an appropriate notation about an amendment, supplement or waiver on any Note thereafter authenticated. The Issuers in exchange for all Notes may issue and
the Trustee shall authenticate new Notes (accompanied by a notation of the Guarantees duly endorsed by the Subsidiary Guarantors) that reflect the amendment, supplement or waiver. Failure to make the
appropriate notation or issue a new Note shall not affect the validity and effect of such amendment, supplement or waiver. 

Section 9.06.
Trustee to Sign Amendments, Etc. 

        The
Trustee shall sign any amended or supplemental Indenture authorized pursuant to this Article 9 if the amendment or supplement does not adversely affect the rights, duties,
liabilities or immunities of the Trustee. In executing any amended or supplemental indenture, the Trustee shall be entitled to receive and (subject to Section 7.01) shall be fully protected in
relying upon, an Officers' Certificate of the Partnership and an Opinion of Counsel stating that the execution of such amended or supplemental indenture is authorized or permitted by this Indenture. 

Section 9.07.
Effect of Supplemental Indentures. 

        Upon
the execution of any supplemental indenture under this Article 9, this Indenture shall be modified in accordance therewith, and such supplemental indenture shall
form a part of this Indenture for all purposes; and every Holder of Notes theretofore or thereafter authenticated and delivered hereunder shall be bound thereby. After a supplemental indenture
becomes effective, the Issuers shall mail to Holders a notice briefly describing such amendment. The failure to give such notice to all Holders, or any defect therein, shall not impair or affect the
validity of an amendment under this Section. 

ARTICLE 10

GUARANTEES  

Section 10.01.
Guarantees. 

        Subject
to the provisions of this Article 10, each of the Subsidiary Guarantors hereby, jointly and severally, unconditionally guarantees to each Holder of a
Note authenticated and delivered by the Trustee and to the Trustee and its successors and assigns, irrespective of the validity and enforceability of this Indenture, the Notes or the other
Obligations of the Issuers hereunder or thereunder, that: (a) the principal of, premium and interest (including Additional Interest, if any) on the Notes shall be promptly paid in full when
due, whether at the maturity or interest payment or mandatory redemption date, by acceleration, redemption or otherwise, and interest on the overdue principal of, premium and interest (including
Additional Interest, if any) on the Notes, if any, to the extent lawful, and all other Obligations of the Issuers to the Holders or the Trustee under this Indenture and the Notes shall be promptly
paid in full or performed, all in accordance with the terms of this Indenture and the Notes; and (b) in case of any extension of time of payment or renewal of any Notes or any of such other
Obligations, that same shall be promptly paid in full when due or performed in accordance with the terms of the extension or renewal, subject to any applicable grace period, whether at Stated
Maturity, by acceleration or otherwise. Failing payment when so due of any amount so guaranteed or any performance so guaranteed for whatever reason, the Subsidiary Guarantors shall be jointly and
severally obligated to pay the same immediately. The Subsidiary Guarantors hereby agree that to the 

69

 

fullest
extent permitted by applicable law, their obligations hereunder shall be unconditional, irrespective of the validity, regularity or enforceability of the Notes or this Indenture, the absence
of any action to enforce the same, any waiver or consent by any Holder of the Notes with respect to any provisions of this Indenture and the Notes, the recovery of any judgment against the Issuers,
any action to enforce the same or any other circumstance (other than complete performance) which might otherwise constitute a legal or equitable discharge or defense of a Subsidiary Guarantor. To the
fullest extent permitted by applicable law, each Subsidiary Guarantor hereby waives diligence, presentment, demand of payment, filing of claims with a court in the event of insolvency or bankruptcy of
the Issuers, any right to require a proceeding first against the Issuers, protest, notice and all demands whatsoever and covenants that its Guarantee shall not be discharged except by complete
performance of the obligations contained in the Notes and this Indenture. 

        If
any Holder or the Trustee is required by any court or otherwise to return to the Issuers or Subsidiary Guarantors, or any custodian, trustee, liquidator or other similar official
acting in relation to either the Issuers or Subsidiary Guarantors, any amount paid by any of them to the Trustee or such Holder, these Guarantees, to the extent theretofore discharged, shall be
reinstated in full force and effect. Each Subsidiary Guarantor agrees that it shall not be entitled to any right of subrogation in relation to the Holders in respect of any Obligations guaranteed
hereby until payment in full of all Obligations guaranteed hereby. 

        Each
Subsidiary Guarantor further agrees that, as between the Subsidiary Guarantors, on the one hand, and the Holders and the Trustee, on the other hand, (x) the maturity of the
Obligations guaranteed hereby may be accelerated as provided in Article 6 hereof for the purposes of these Guarantees, notwithstanding any stay, injunction or other prohibition preventing such
acceleration in respect of the Obligations guaranteed hereby, and (y) in the event of any declaration of acceleration of such Obligations as provided in Article 6 hereof, such
Obligations (whether or not due and payable) shall forthwith become due and payable by the Subsidiary Guarantors for the purpose of these Guarantees. The Subsidiary Guarantors shall have the right to
seek contribution from any non-paying Subsidiary Guarantor so long as the exercise of such right does not impair the rights of the Holders under these Guarantees. 

Section 10.02.
Limitation of Guarantor's Liability. 

        Each
Subsidiary Guarantor and, by its acceptance hereof, each Holder hereby confirms that it is its intention that the Guarantee by such Subsidiary Guarantor not constitute a fraudulent
transfer or conveyance for purposes of the Bankruptcy Law, the Uniform Fraudulent Conveyance Act, the Uniform Fraudulent Transfer Act or any similar federal or state law to the extent applicable to
the Guarantees. To effectuate the foregoing intention, each such Person hereby irrevocably agrees that the Obligation of such Subsidiary Guarantor under its Guarantee under this Article 10
shall be limited to the maximum amount as shall, after giving effect to such maximum amount and all other (contingent or otherwise) liabilities of such Subsidiary Guarantor that are relevant under
such laws, and after giving effect to any rights to contribution of such Subsidiary Guarantor pursuant to any agreement providing for an equitable contribution among such Subsidiary Guarantor and
other Affiliates of the Issuers of payments made by guarantees by such parties, result in the Obligations of such Subsidiary Guarantor in respect of such maximum amount not constituting a fraudulent
conveyance. Each Holder, by accepting the benefits hereof, confirms its intention that, in the event of bankruptcy, reorganization or other similar proceeding of either of the Issuers or any
Subsidiary Guarantor in which concurrent claims are made upon such Subsidiary Guarantor hereunder, to the extent such claims shall not be fully satisfied, each such claimant with a valid claim against
such Issuer shall be entitled to a ratable share of all payments by such Subsidiary Guarantor in respect of such concurrent claims. 

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Section 10.03.
Execution and Delivery of Notations of Guarantees. 

        To
evidence the Guarantees set forth in Section 10.01 hereof, each Subsidiary Guarantor hereby agrees that a notation of the Guarantees substantially in the form of
Exhibit D shall be endorsed on each Note authenticated and delivered by the Trustee and that this Indenture shall be executed on behalf of such Subsidiary Guarantor by one of its
Officers. 

        Each
Subsidiary Guarantor hereby agrees that the Guarantees set forth in Section 10.01 shall remain in full force and effect notwithstanding any failure to endorse on each
Note a notation of the Guarantees. If an Officer whose signature is on this Indenture or on the notation of Guarantees no longer holds that office at the time the Trustee authenticates the
Note on which the notation of the Guarantees is endorsed, the Guarantees shall be valid nevertheless. 

        The
delivery of any Note by the Trustee, after the authentication thereof hereunder, shall constitute due delivery of the Guarantees set forth in this Indenture on behalf of the
Subsidiary Guarantors. 

Section 10.04.
[Intentionally omitted]. 

Section 10.05.
Releases. 

        Concurrently
with any sale of assets (including, if applicable, all of the Equity Interests of any Subsidiary Guarantor), any Liens in favor of the Trustee in the assets sold thereby
shall be released; provided that in the event of an Asset Sale, the Net Proceeds from such sale or other disposition are treated in accordance with the provisions of Section 4.07 hereof. The
Guarantee and all other obligations under this Indenture of a Subsidiary Guarantor will be released: (i) in connection with any sale or other disposition of all or substantially all of the
assets of such Subsidiary Guarantor (including by way of merger or consolidation) to a Person that is not (either before or after giving effect to such transaction) a Restricted Subsidiary, if the
Partnership applies the Net Proceeds of that sale or other disposition in accordance with Section 4.07 hereof; or (ii) in connection with any sale or other disposition of all of the
Equity Interests of a Subsidiary Guarantor to a Person that is not (either before or after giving effect to such transaction) a Restricted Subsidiary, if the Partnership applies the Net Proceeds of
that sale in accordance with Section 4.07 hereof; or (iii) if the Partnership designates any Restricted Subsidiary that is a Subsidiary Guarantor as an Unrestricted Subsidiary; or
(iv) upon Legal Defeasance or Covenant Defeasance pursuant to Article 8 hereof or upon satisfaction and discharge of this Indenture pursuant to Article 11 hereof; or (v) in
the case of any Subsidiary Guarantor other than the Operating Company, at such time as such Subsidiary Guarantor ceases to guarantee any other Indebtedness of either of the Issuers and any
Indebtedness of the Operating Company; or (vi) in the case of the Operating Company, at such time as the Operating Company ceases to guarantee any other Indebtedness of either of the Issuers,
provided that it is then no longer an obligor with respect to any Indebtedness under any Credit Facility. Upon delivery by the Partnership to the Trustee of an Officers' Certificate to the effect that
such sale or other disposition was made by the Partnership in accordance with the provisions of this Indenture, including without limitation Section 4.07 hereof or such Guarantee is to be
released pursuant to the provisions of the immediately preceding sentence, the Trustee shall execute any documents reasonably required in order to evidence the release of any Subsidiary Guarantor from
all of its obligations under its Guarantee and this Indenture. Any Subsidiary Guarantor not released from its obligations under its Guarantee shall remain liable for the full amount of principal of
and interest on the Notes and for the other obligations of any Subsidiary Guarantor under this Indenture as provided in this Article 10. 

Section 10.06.
"Trustee" to Include Paying Agent. 

        In
case at any time any Paying Agent other than the Trustee shall have been appointed by the Issuers and be then acting hereunder, the term "Trustee" as used in this Article 10
shall in such case (unless the context shall otherwise require) be construed as extending to and including such Paying 

71

 

Agent
within its meaning as fully and for all intents and purposes as if such Paying Agent were named in this Article 10 in place of the Trustee. 

ARTICLE 11

SATISFACTION AND DISCHARGE  

Section 11.01.
Satisfaction and Discharge. 

        This
Indenture shall upon the request of the Issuers cease to be of further effect (except as to surviving rights of registration of transfer or exchange of Notes herein expressly
provided for, the Issuers' obligations under Section 7.07 hereof, the Issuers' rights of optional redemption under Article 3 hereof, and the Trustee's and the Paying Agent's obligations
under Section 11.02 and 11.03 hereof) and the Trustee, at the expense of the Issuers, shall execute proper instruments acknowledging satisfaction and discharge of this Indenture when 

        (a)   either

        (i)    all
Notes theretofore authenticated and delivered (other than (A) Notes which have been destroyed, lost or stolen and which have been replaced or paid as provided
in Section 2.07 and (B) Notes for whose payment money has been deposited in trust with the Trustee or any Paying Agent and thereafter paid to the Issuers or discharged from such trust)
have been delivered to the Trustee for cancellation; or 

        (ii)   all
such Notes not theretofore delivered to the Trustee for cancellation 

        (A)  have
become due and payable; or 

        (B)  shall
become due and payable at their Stated Maturity within one year by reason of the mailing of a notice of redemption or otherwise, or 

        (C)  are
to be called for redemption within one year under arrangements satisfactory to the Trustee for the giving of notice of redemption by the Trustee in the name, and at
the expense, of the Issuers, 

and
the Issuers or any Subsidiary Guarantor, in the case of clause (A), (B) or (C) above, has irrevocably deposited or caused to be deposited with the Trustee as trust funds in
trust for the benefit of the Holders, cash in U.S. dollars, U.S. Government Obligations or a combination of cash in U.S. dollars and U.S. Government Obligations, in amounts as will be sufficient
without consideration of any reinvestment of interest, to pay and discharge the entire indebtedness on the Notes not delivered to the Trustee for cancellation for principal, premium, if any, and
accrued interest to the date of fixed maturity or redemption; 

        (b)   no
Default or Event of Default shall have occurred and be continuing on the date of such deposit or will occur as a result of such deposit and such deposit will not
result in a breach or violation of, or constitute a default under, any material agreement or instrument (other than this Indenture) to which the Partnership or any of its Subsidiaries is a party or by
which the Partnership or any of its Subsidiaries is bound; and 

        (c)   the
Issuers or any Subsidiary Guarantor has paid or caused to be paid all sums then due and payable hereunder by the Issuers; 

        (d)   the
Issuers have delivered irrevocable instructions to the Trustee to apply the deposited money toward the payment of the Notes at fixed maturity or the redemption date,
as the case may be; and 

72

   
        (e)   the Issuers have delivered to the Trustee an Officers' Certificate and an Opinion of Counsel, each stating that all conditions precedent herein provided for relating to
the satisfaction and discharge of this Indenture have been satisfied. 

        Notwithstanding
the satisfaction and discharge of this Indenture, the Issuers' obligations in Sections 2.03, 2.04, 2.06, 2.07, 2.11, 7.07, 7.08, 11.02, 11.03 and 11.04, and the
Trustee's and Paying Agent's obligations in Section 11.03 shall survive until the Notes are no longer outstanding. Thereafter, only the Issuers' obligations in Section 11.03 shall
survive. 

        In
order to have money available on a payment date to pay principal (and premium, if any, on) or interest on the Notes, the U.S. Government Obligations shall be payable as to principal
(and premium, if any) or interest at least one Business Day before such payment date in such amounts as shall provide the necessary money. The U.S. Government Obligations shall not be callable at the
issuer's option. 

Section 11.02.
Application of Trust. 

        All
money deposited with the Trustee pursuant to Section 11.01 shall be held in trust and, at the written direction of the Issuers, be invested prior to maturity in U.S.
Government Obligations, and applied by the Trustee in accordance with the provisions of the Notes and this Indenture, to the payment, either directly or through any Paying Agent as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if any) and interest for the payment of which money has been deposited with the Trustee; but such money need not be
segregated from other funds except to the extent required by law. 

Section 11.03.
Repayment of the Issuers. 

        The
Trustee and the Paying Agent shall promptly pay to the Issuers upon written request any excess money or securities held by them at any time. 

        Subject
to applicable escheat laws, the Trustee and the Paying Agent shall notify the Issuers of, and pay to the Issuers upon written request, any money held by them for the payment of
principal or interest that remains unclaimed for two years after the date upon which such payment shall have become due;
provided that the Issuers shall have either caused notice of such payment to be mailed to each Holder of the Notes entitled thereto no less than 30 days prior to such repayment or within such
period shall have published such notice in a financial newspaper of widespread circulation published in The City of New York, including, without limitation, The Wall Street
Journal (national edition). After payment to the Issuers, Holders entitled to the money must look to the Issuers for payment as general creditors unless an applicable abandoned
property law designates another Person, and all liability of the Trustee and such Paying Agent with respect to such money shall cease. In the absence of a written request from the Issuers to return
unclaimed funds to the Issuers, the Trustee shall from time to time deliver all unclaimed funds to or as directed by applicable escheat authorities, as determined by the Trustee in its sole
discretion, in accordance with the customary practices and procedures of the Trustee. 

Section 11.04.
Reinstatement. 

        If
the Trustee or Paying Agent is unable to apply any money or U.S. Government Obligations in accordance with Section 11.01 by reason of any legal proceeding or by reason of any
order or judgment of any court of governmental authority enjoining, restraining or otherwise prohibiting such application, the Issuers' and Subsidiary Guarantors' Obligations under this Indenture, the
Notes and the Guarantees, as applicable, shall be revived and reinstated as though no deposit has occurred pursuant to Section 11.01 until such time as the Trustee or Paying Agent is permitted
to apply all such money or U.S. Government Obligations in accordance with Section 11.02, provided, however, that if the Issuers or the Subsidiary Guarantors have made any payment of interest or
premium, if any, on or principal of any Notes because of the reinstatement of their Obligations, the Issuers or such Subsidiary Guarantors 

73

 

shall
be subrogated to the rights of the Holders of such Notes to receive such payment from the money or U.S. Government Obligations held by the Trustee or Paying Agent. 

ARTICLE 12

MISCELLANEOUS  

Section 12.01.
Trust Indenture Act Controls. 

        If
any provision of this Indenture limits, qualifies or conflicts with the duties imposed by TIA Section 318(c), the imposed duties shall control. 

Section 12.02.
Notices. 

        Any
notice or communication by the Issuers or the Trustee to the others is duly given if in writing (in the English language) and delivered in person or mailed by first class mail
(registered or certified, return receipt requested), telecopier or overnight air courier guaranteeing next day delivery, to the others' address: 

        If
to the Issuers or any Subsidiary Guarantor: 

MarkWest
Energy Partners, L.P.

155 Inverness Drive West, Suite 200

Englewood, Colorado 80112

Telecopier No.: (303) 925-9307

Attention: Chief Financial Officer 

        With
a copy to: 

Vinson &
Elkins L.L.P.

2300 First City Tower

1001 Fannin St.

Houston, Texas 77002

Telecopier No.: (713) 615-5861

Attention: David P. Oelman, Esq. 

        If
to the Trustee or Paying Agent: 

Wells
Fargo Bank, National Association

505 Main Street, Suite 301

Fort Worth, Texas 76102

Attention: Corporate Trust Department

Telecopier No.: (817) 885-8650 

        The
Issuers, any Subsidiary Guarantor or the Trustee, by notice to the others may designate additional or different addresses for subsequent notices or communications. 

        All
notices and communications (other than those sent to Holders) shall be deemed to have been duly given: at the time delivered by hand, if personally delivered; five Business Days
after being deposited in the mail, postage prepaid, if mailed; when receipt is acknowledged, if sent by facsimile transmission; and the next Business Day after timely delivery to the courier, if sent
by overnight air courier guaranteeing next day delivery. 

        Any
notice or communication to a Holder shall be mailed by first class mail, certified or registered, return receipt requested, or by overnight air courier guaranteeing next day delivery
to its address shown on the register kept by the Registrar. Any notice or communication shall also be so mailed to any Person described in TIA Section 313(c), to the extent required by the TIA.
Failure to 

74

 

mail
a notice or communication to a Holder or any defect in it shall not affect its sufficiency with respect to other Holders. 

        If
a notice or communication is mailed in the manner provided above within the time prescribed, it is duly given, whether or not the addressee receives it. 

        If
either of the Issuers mails a notice or communication to Holders, it shall mail a copy to the Trustee and each Agent at the same time. 

Section 12.03.
Communication by Holders of Notes with Other Holders of Notes. 

        The
Trustee is subject to TIA Section 312(b), and Holders may communicate pursuant thereto with other Holders with respect to their rights under this Indenture or the Notes. The
Issuers, the Subsidiary Guarantors, the Trustee, the Registrar and anyone else shall have the protection of TIA Section 312(c). 

Section 12.04.
Certificate and Opinion as to Conditions Precedent. 

        Upon
any request or application by the Issuers or any Subsidiary Guarantor to the Trustee to take any action under this Indenture, the Issuers or such Subsidiary Guarantors shall furnish
to the Trustee: 

        (a)   an
Officers' Certificate in form and substance reasonably satisfactory to the Trustee (which shall include the statements set forth in Section 12.05 hereof)
stating that, in the opinion of the signers, all conditions precedent and covenants, if any, provided for in this Indenture relating to the proposed action have been satisfied; and 

        (b)   an
Opinion of Counsel in form and substance reasonably satisfactory to the Trustee (which shall include the statements set forth in Section 12.05 hereof) stating
that, in the opinion of such counsel, all such conditions precedent and covenants have been satisfied. 

        In
any case where several matters are required to be certified by, or covered by an opinion of, any specified Person, it is not necessary that all such matters be certified by, or
covered by the opinion of, only one such Person, or that they be so certified or covered by only one document, but one such Person may certify or give an opinion with respect to some matters and one
or more such Persons as to other matters, and any such Person may certify or give an opinion as to such matters in one or several documents. 

        Any
certificate or opinion of an Officer of the General Partner, an Issuer or any Subsidiary Guarantor may be based, insofar as it relates to legal matters, upon a certificate or opinion
of, or representations by, counsel, unless such Officer knows, or in the exercise of reasonable care should know, that the certificate or opinion or representations with respect to the matters upon
which his certificate or opinion is based are erroneous. Any such certificate or Opinion of Counsel may be based, and may state that it is so based, insofar as it relates to factual matters, upon a
certificate or opinion of, or representations by, an Officer or Officers of the General Partner, an Issuer or such Subsidiary Guarantor stating that the information with respect to such factual
matters is in possession of the General Partner, an Issuer or such Subsidiary Guarantor, unless such counsel knows, or in the exercise of reasonable care should know, that the certificate of opinion
or representations with respect to such matters are erroneous. 

        Where
any Person is required to make, give or execute two or more applications, requests, consents, certificates, statements, opinions or other instruments under this Indenture, they
may, but need not, be consolidated and form one instrument. 

75

 

Section 12.05.
Statements Required in Certificate or Opinion. 

        Each
certificate or opinion with respect to compliance with a condition or covenant provided for in this Indenture (other than a certificate provided pursuant to TIA
Section 314(a)(4)) shall comply with the provisions of TIA Section 314(e) and shall include: 

        (a)   a
statement that the person making such certificate or opinion has read such covenant or condition; 

        (b)   a
brief statement as to the nature and scope of the examination or investigation upon which the statements or opinions contained in such certificate or opinion are
based; 

        (c)   a
statement that, in the opinion of such person, he or she has made such examination or investigation as is necessary to enable him or her to express an informed opinion
as to whether or not such covenant or condition has been satisfied; and 

        (d)   a
statement as to whether or not, in the opinion of such person, such condition or covenant has been complied with. 

Section 12.06.
Rules by Trustee and Agents. 

        The
Trustee may make reasonable rules for action by or at a meeting of Holders. The Registrar or Paying Agent may make reasonable rules and set reasonable requirements for its functions. 

Section 12.07.
No Personal Liability of Directors, Officers, Employees and Unitholders and No Recourse Against General Partner. 

        Neither
the General Partner nor any past, present or future director, officer, partner, employee, incorporator, manager or unitholder or other owner of Equity Interests of the Issuers,
the General Partner or any Subsidiary Guarantor, as such, shall have any liability for any Obligations of the Issuers or the Subsidiary Guarantors under the Notes, this Indenture or the Guarantees or
for any claim based on, in respect of, or by reason of, such Obligations or their creation. Each Holder by accepting a Note waives and releases all such liability. The waiver and release are
part of the consideration for issuance of the Notes. 

Section 12.08.
Governing Law. 

        THE
LAWS OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS INDENTURE, THE NOTES AND THE GUARANTEES. 

Section 12.09.
No Adverse Interpretation of Other Agreements. 

        This
Indenture may not be used to interpret any other indenture, loan or debt agreement of either of the Issuers or any Subsidiary of the Partnership or of any other Person. Any such
indenture, loan or debt agreement may not be used to interpret this Indenture or the Guarantees. 

Section 12.10.
Successors. 

        All
agreements of the Issuers and the Subsidiary Guarantors in this Indenture, the Notes and the Guarantees shall bind their respective successors. All agreements of the Trustee in this
Indenture shall bind its successors. 

Section 12.11.
Severability. 

        In
case any provision in this Indenture, the Notes or the Guarantees shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions
shall not in any way be affected or impaired thereby. 

76

 

Section 12.12.
Counterpart Originals. 

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

Section 12.13.
Table of Contents, Headings, Etc. 

        The
Table of Contents, Cross-Reference Table and headings of the Articles and Sections of this Indenture have been inserted for convenience of reference only, are not to be
considered a part of this Indenture and shall in no way modify or restrict any of the terms or provisions hereof. 

[Signatures
on following pages] 

77

 

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

	

Issuers:	
 	

 
	

MARKWEST ENERGY PARTNERS, L.P.	
 	

 
	

By:	

 	

MARKWEST ENERGY GP, L.L.C., its general partner	

 	

 
	

 	
 	

By:	
 	

/s/  ANDREW L. SCHROEDER      
	
 	

 
	 	 	Name:	 	Andrew L. Schroeder	 	 
	 	 	Title:	 	Vice President	 	 
	

MARKWEST ENERGY FINANCE CORPORATION	
 	

 
	

By:	
 	

/s/  ANDREW L. SCHROEDER      
	
 	

 
	Name:	 	Andrew L. Schroeder	 	 
	Title:	 	Vice President	 	 

	

 	
 	

Subsidiary Guarantors:
	

 	
 	

MARKWEST ENERGY OPERATING COMPANY, L.L.C.

BASIN PIPELINE L.L.C.

WEST SHORE PROCESSING COMPANY, L.L.C.

MARKWEST ENERGY APPALACHIA, L.L.C.

MARKWEST TEXAS GP, L.L.C.

MW TEXAS LIMITED, L.L.C.

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C.

MARKWEST WESTERN OKLAHOMA GAS COMPANY, L.L.C.
	

 	
 	

By:	
 	

/s/  ANDREW L. SCHROEDER      

	 	 	Name:	 	Andrew L. Schroeder
	 	 	Title:	 	Vice President
	 	 	 	 	 	 	 

78

 

	

 	
 	

MARKWEST POWER TEX L.P.

MARKWEST PINNACLE L.P.

MARKWEST PNG UTILITY L.P.

MARKWEST TEXAS PNG UTILITY L.P.

MARKWEST BLACKHAWK L.P.

MARKWEST NEW MEXICO L.P.

MARKWEST ENERGY EAST TEXAS GAS COMPANY L.P.
	

 	
 	

By:	
 	

MARKWEST TEXAS GP, L.L.C., its general partner
	

 	
 	

 	
 	

By:	
 	

/s/  ANDREW L. SCHROEDER      

	 	 	 	 	Name:	 	Andrew L. Schroeder
	 	 	 	 	Title:	 	Vice President
	

 	
 	

Trustee:
	

 	
 	

WELLS FARGO BANK, NATIONAL ASSOCIATION, as Trustee
	

 	
 	

By:	
 	

/s/  MELISSA A. SCOTT      

	 	 	Name:	 	Melissa A. Scott
	 	 	Title:	 	Vice President

79

   SCHEDULE A  

 Schedule of Subsidiary Guarantors  

MarkWest
Energy Operating Company, L.L.C.

Basin Pipeline L.L.C.

West Shore Processing Company, L.L.C.

MarkWest Energy Appalachia, L.L.C.

MarkWest Texas GP, L.L.C.

MW Texas Limited, L.L.C.

MarkWest Michigan Pipeline Company, L.L.C.

MarkWest Western Oklahoma Gas Company, L.L.C.

MarkWest Power Tex L.P.

MarkWest Pinnacle L.P.

MarkWest PNG Utility L.P.

MarkWest Texas PNG Utility L.P.

MarkWest Blackhawk L.P.

MarkWest New Mexico L.P.

MarkWest Energy East Texas Gas Company L.P. 

80

   SCHEDULE B  

 Certain Agreements  

	1.
	Omnibus
Agreement dated as of May 24, 2002, between MarkWest Hydrocarbon, Inc., MarkWest Energy Partners, L.P., MarkWest Energy GP, L.L.C. and MarkWest Energy Operating
Company, L.L.C.

	2.
	Fractionation,
Storage and Loading Agreement dated as of May 24, 2002, between MarkWest Energy Appalachia, L.L.C. and MarkWest Hydrocarbon, Inc.

	3.
	Gas
Processing Agreement dated as of May 24, 2002, between MarkWest Energy Appalachia, L.L.C. and MarkWest Hydrocarbon, Inc.

	4.
	Pipeline
Liquids Transportation Agreement dated as of May 24, 2002, between MarkWest Energy Appalachia, L.L.C. and MarkWest Hydrocarbon, Inc.

	5.
	Natural
Gas Liquids Purchase Agreement dated as of May 24, 2002, between MarkWest Energy Appalachia, L.L.C. and MarkWest Hydrocarbon, Inc.

	6.
	Gas
Processing Agreement (Maytown) dated as of May 28, 2002, between Equitable Production Company and MarkWest Hydrocarbon, Inc

	7.
	Amendment
to Gas Processing Agreement (Maytown) dated as of March 26, 2002, between Equitable Production Company and MarkWest Hydrocarbon, Inc.

	8.
	Services
Agreement dated as of January 1, 2004, by and between MarkWest Energy GP, L.L.C. and MarkWest Hydrocarbon, Inc.

	9.
	Agreement
for Construction and Removal dated as of October 10, 2003, between MarkWest Hydrocarbon, Inc. and MarkWest Energy Appalachia, L.L.C. 

81

   EXHIBIT A  

(Face
of Note) 

THIS
GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE INDENTURE GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF THE BENEFICIAL OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY
PERSON UNDER ANY CIRCUMSTANCES EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED PURSUANT TO SECTION 2.06 OF THE INDENTURE, (II) THIS GLOBAL
NOTE MAY BE EXCHANGED PURSUANT TO SECTION 2.06(a) OF THE INDENTURE, (III) THIS GLOBAL NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT TO SECTION 2.11 OF THE
INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO A SUCCESSOR DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF THE ISSUERS.(1) 

UNLESS
AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES IN DEFINITIVE FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A
NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY. UNLESS
THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK) ("DTC"), TO THE ISSUERS OR THEIR AGENT FOR REGISTRATION OF TRANSFER,
EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS MAY BE REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS
MADE TO CEDE & CO. OR SUCH OTHER ENTITY AS MAY BE REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON
IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.(1) 

	(1)
	This
is included in Global Notes only. 

THIS
SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. NEITHER THIS SECURITY NOR ANY
INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS SUCH TRANSACTION IS EXEMPT
FROM, OR NOT SUBJECT TO, SUCH REGISTRATION. THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES ON ITS OWN BEHALF AND ON BEHALF OF ANY INVESTOR ACCOUNT FOR WHICH IT HAS PURCHASED SECURITIES,
TO OFFER, SELL OR OTHERWISE TRANSFER SUCH SECURITY, PRIOR TO THE DATE (THE "RESALE RESTRICTION TERMINATION DATE") THAT IS [IN THE CASE OF NOTES SOLD IN RELIANCE ON
RULE 144A UNDER THE SECURITIES ACT: TWO YEARS] [IN THE CASE OF NOTES SOLD IN RELIANCE ON REGULATION S UNDER THE SECURITIES ACT:
40 DAYS] AFTER THE LATER OF THE ORIGINAL ISSUE DATE HEREOF AND THE LAST DATE ON WHICH EITHER ISSUER OR ANY AFFILIATE OF EITHER ISSUER WAS THE OWNER OF THIS SECURITY
(OR ANY PREDECESSOR OF SUCH SECURITY), ONLY (A) TO AN ISSUER OR ITS SUBSIDIARY, (B) PURSUANT TO A REGISTRATION STATEMENT THAT HAS BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT,
(C) FOR SO LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A UNDER THE 

Exhibit A, Page 1

 

SECURITIES
ACT, TO A PERSON IT REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A
QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) PURSUANT TO OFFERS AND SALES THAT OCCUR OUTSIDE THE UNITED STATES WITHIN THE
MEANING OF REGULATION S UNDER THE SECURITIES ACT, (E) TO AN INSTITUTIONAL "ACCREDITED INVESTOR" WITHIN THE MEANING OF RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT THAT
IS AN INSTITUTIONAL ACCREDITED INVESTOR ACQUIRING THE SECURITY FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL ACCREDITED INVESTOR, IN EACH CASE IN A MINIMUM PRINCIPAL AMOUNT OF THE
SECURITIES OF $250,000, FOR INVESTMENT PURPOSES AND NOT WITH A VIEW TO OR FOR OFFER OR SALE IN CONNECTION WITH ANY DISTRIBUTION IN VIOLATION OF THE SECURITIES ACT, OR (F) PURSUANT TO ANOTHER
AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT, SUBJECT TO THE ISSUERS' AND THE TRUSTEE'S RIGHT PRIOR TO ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSES (C), (D),
(E) OR (F) TO REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION SATISFACTORY TO EACH OF THEM. THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF THE
HOLDER AFTER THE RESALE RESTRICTION TERMINATION DATE.(2) 

	(2)
	Legend
appears only on the Series A Notes 

        CUSIP:                        

6.875%
[Series A] [Series B] Senior Notes due 2014 

	No. 	 	$                  

MARKWEST
ENERGY PARTNERS, L.P.

and

MARKWEST ENERGY FINANCE CORPORATION 

promise
to pay to                        or registered assigns, the principal sum
of                        Dollars of the United States of America [or such greater or lesser amount as may from time to
time be endorsed on the Schedule of Exchanges of Interests in the Global Note](3) on November 1, 2014. 

	(3)
	This
is included in Global Notes only. 

Interest
Payment Dates: May 1 and November 1 of each year 

Record
Dates: April 15 and October 15 

        Reference
is hereby made to the further provisions of this Note set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set
forth at this place. 

Exhibit A, Page 2

 

        Unless
the certificate of authorization hereon has been duly executed by the Trustee referred to on the reverse hereof by manual signature, this Note shall not be entitled to any
benefit of this Indenture or be valid or obligatory for any purpose. 

	

MARKWEST ENERGY FINANCE CORPORATION	
 	

MARKWEST ENERGY PARTNERS, L.P.
	

 	
 	

 	
 	

By:	
 	

MarkWest Energy GP, L.L.C., its General Partner
	

By:	
 	

	
 	

By:	
 	

	Name:	 	 	 	Name:	 	 
	 	 	
	 	 	 	

	Title:	 	 	 	Title:	 	 
	 	 	
	 	 	 	

Certificate
of Authentication: 

This
is one of the Notes referred to in the within-mentioned Indenture. 

WELLS
FARGO BANK, NATIONAL ASSOCIATION, as Trustee 

	

By:	
 	

 Authorized Signatory	
 	

 

Date
of Authentication:                        ,        

Exhibit A, Page 3

 
[Back
of Note] 

6.875%
[Series A] [Series B] Senior Note due 2014 

        Capitalized
terms used herein shall have the meanings assigned to them in the Indenture referred to below unless otherwise indicated. 

        1.     Interest.
MarkWest Energy Partners, L.P., a Delaware limited partnership (the "Partnership"), and MarkWest Energy Finance Corporation, a Delaware corporation ("MarkWest
Finance" and, together with the Partnership, the "Issuers"), promise to pay interest on the principal amount of this Note at 6.875% per annum and shall pay any Additional Interest payable
pursuant to Section     of the Registration Rights Agreement referred to below. The Issuers will pay interest (including Additional Interest, if any) semi-annually on
May 1 and October 1 of each year, or if any such day is not a Business Day, on the next succeeding Business Day (each an "Interest Payment Date"). Interest on the Notes will accrue from
the most recent date to which interest has been paid or, if no interest has been paid,
from                                    ,
            ; provided that if there is no existing Default in the
payment of interest, and if this Note is authenticated between a record date referred to on the face hereof and the next succeeding Interest Payment Date, interest shall accrue from such next
succeeding Interest Payment Date; provided, further, that the first Interest Payment Date shall be May 1, 2005. The Issuers shall pay interest (including post-petition interest in
any proceeding under any Bankruptcy Law) on overdue principal and premium, if any, from time to time on demand at the rate then in effect; the Issuers shall pay interest (including
post-petition interest in any proceeding under any Bankruptcy Law) on overdue installments of interest (including Additional Interest, if any), without regard to any applicable grace
periods, from time to time on demand at the same rate to the extent lawful. Interest will be computed on the basis of a 360-day year comprised of twelve 30-day months. 

        2.     Method
of Payment. The Issuers will pay interest (including Additional Interest, if any) on the Notes (except defaulted interest) to the Persons who are registered
Holders of Notes at the close of business on the April 15 or October 15 next preceding the Interest Payment Date, even if such Notes are cancelled after such record date and on or before
such Interest Payment Date, except as provided in Section 2.12 of the Indenture with respect to defaulted interest. The Notes will be payable as to principal, premium and interest (including
Additional Interest, if any) at the office or agency of the Paying Agent maintained for such purpose within the City and State of New York, or, at the option of the Issuers, payment of interest
(including Additional Interest, if any) may be made by check mailed to the Holders at their addresses set forth in the register of Holders, and provided that payment by wire transfer of immediately
available funds will be required with respect to principal of, interest (including Additional Interest, if any) and premium on, all Global Notes and all other Notes the Holders of which shall have
provided wire transfer instructions to the Issuers or the Paying Agent. Such payment shall be in such coin or currency of the United States of America as at the time of payment is legal tender for
payment of public and private debts. 

        3.     Paying
Agent and Registrar. Initially, Wells Fargo Bank, National Association, the Trustee under the Indenture, will act as Paying Agent and Registrar. The Issuers may
change any Paying Agent or Registrar without prior notice to any Holder. The Issuers or any of their Subsidiaries may act in any such capacity. 

        4.     Indenture.
The Issuers issued the Notes under an Indenture dated as of October 25, 2004 ("Indenture") among the Issuers, the Subsidiary Guarantors and the Trustee.
The terms of the Notes include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (15 U.S. Code
Sections 77aaa-77bbbb). The Notes are subject to all such terms, and Holders are referred to the Indenture and such Act for a statement of such terms. To the extent any provision of
this Note conflicts with the express provisions of the Indenture, the provisions of the Indenture shall govern and be controlling to the extent permitted by law. The Notes are unsecured general
obligations of the Issuers. 

Exhibit A, Page 4

 

        5.     Optional
Redemption. Subject to the additional terms and conditions set forth in the Indenture: 

        (a)   On
and after November 1, 2009, the Issuers shall have the option to redeem the Notes, in whole or in part from time to time, on at least 30 but not more than
60 days' prior notice mailed to the registered address of each Holder of Notes to be so redeemed, at the redemption prices (expressed as percentages of principal amount) set forth below, plus
accrued and unpaid interest (including Additional Interest, if any), if any, to the applicable redemption date (subject to the rights of Holders of record on the relevant record date to receive
interest due on an Interest Payment Date that is on or prior to the redemption date), if redeemed during the twelve-month period beginning on November 1 of the years indicated below: 

	Year
 
	 	Percentage
	 
	2009	 	103.438	%
	2010	 	102.292	%
	2011	 	101.146	%
	2012 and thereafter	 	100.000	%

        (b)   On
or before November 1, 2009, the Issuers may redeem all or, from time to time, a part of the Notes upon not less than 30 nor more than 60 days' notice,
at a redemption price equal to: 

        (i)    100%
of the aggregate principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to the applicable redemption date (subject to the right of
Holders of record on the relevant record date to receive interest due on an Interest Payment Date that is on or prior to the redemption date), plus 

        (ii)   the
Make Whole Amount. 

        (c)   On
or before November 1, 2007, the Issuers may on any one or more occasions redeem in the aggregate up to 35% of the aggregate principal amount of Notes issued
under the Indenture with the net cash proceeds of one or more Equity Offerings at a redemption price equal to 106.875% of the principal amount of the Notes to be redeemed, plus accrued and unpaid
interest, if any, to the redemption date (subject to the right of Holders of record on a record date to receive interest due on the relevant Interest Payment Date that is on or prior to the redemption
date); provided that 

        (i)    at
least 65% of the aggregate principal amount of Notes issued under the Indenture remains outstanding after each such redemption; and 

        (ii)   any
redemption occurs within 60 days after the closing of such Equity Offering (without regard to any over-allotment option). 

        6.     Mandatory
Redemption. Except as set forth in paragraph 7 below, the Issuers shall not be required to make mandatory redemption payments with respect to the Notes. 

        7.     Repurchase
at Option of Holder. Subject to the additional terms and conditions set forth in the Indenture: 

        (a)   If
there is a Change of Control, each Holder of Notes will have the right to require the Issuers to repurchase all or any part (equal to $1,000 or an integral multiple
thereof) of such Holder's Notes (the "Change of Control Offer") at a purchase price equal to 101% of the aggregate principal amount of the Notes repurchased plus accrued and unpaid interest (including
Additional Interest, if any) thereon, if any, to the date of purchase. Within 30 days following any Change of Control, the Issuers shall mail a notice to each Holder setting forth the
procedures governing the Change of Control Offer as required by the Indenture and information regarding such other matters as is required under Section 4.06 of the Indenture. The Holder of this
Note may elect to have this Note or a portion hereof 

Exhibit A, Page 5

 

in
an authorized denomination purchased by completing the form entitled "Option of Holder to Elect Purchase" appearing below and tendering this Note pursuant to the Change of Control Offer. 

        (b)   If
the Issuers or any Restricted Subsidiary of the Partnership consummates an Asset Sale, in certain circumstances specified in Section 4.07 of the Indenture the
Issuers shall commence a pro rata offer to all Holders of Notes and all holders of other Indebtedness that is pari passu in right of payment with the
Notes containing provisions similar to those set forth in the Indenture with respect to offers to purchase or redeem with the proceeds of sales of assets (an "Asset Sale Offer") pursuant to
Section 3.09 of the Indenture to purchase the maximum principal amount of Notes and such other pari passu Indebtedness that may be purchased out
of the Excess Proceeds at an offer price in cash in an amount equal to 100% of the principal amount thereof plus accrued and unpaid interest (including Additional Interest, if any, in the case of the
Notes) thereon, if any, to the date of purchase in accordance with the procedures set forth in the Indenture. If the aggregate principal amount of Notes surrendered by Holders thereof exceeds the
amount of Excess Proceeds allocated for repurchase of Notes, the Trustee shall select the Notes to be purchased on a pro rata basis. Holders of Notes that are the subject of an Asset Sale Offer will
receive an offer to purchase from the Issuers prior to any related purchase date and may elect to have such Notes purchased by completing the form entitled "Option of Holder to Elect Purchase" on the
reverse of the Notes. 

        8.     Notice
of Redemption. Notice of redemption will be mailed at least 30 days but not more than 60 days before the redemption date to each Holder whose Notes
are to be redeemed at its registered address. Notes in denominations larger than $1,000 may be redeemed in part but only in whole multiples of $1,000, unless all of the Notes held by a Holder are to
be redeemed. On and after the redemption date interest (including Additional Interest, if any) ceases to accrue on Notes or portions thereof called for redemption unless the Issuers defaults in making
such redemption payment. 

        9.     Denominations,
Transfer, Exchange. The Notes are in registered form without coupons in denominations of $1,000 and integral multiples of $1,000. The transfer of Notes may
be registered and Notes may be exchanged as provided in the Indenture. The Registrar and the Trustee may require a Holder, among other things, to furnish appropriate endorsements and transfer
documents and the Issuers may require a Holder to pay any taxes and fees required by law or permitted by the Indenture. The Issuers need not exchange or register the transfer of any Note or portion of
a Note selected for redemption, except for the portion of any Note being redeemed in part that is not being redeemed. Also, the Issuers need not exchange or register the transfer of any
Notes for a period of 15 days before the mailing of a notice of redemption or during the period between a record date and the corresponding Interest Payment Date. 

        10.   Persons
Deemed Owners. The registered Holder of a Note may be treated as its owner for all purposes. 

        11.   Amendment,
Supplement and Waiver. Subject to certain exceptions, the Indenture, the Guarantees or the Notes may be amended or supplemented with the consent of the
Holders of at least a majority in aggregate principal amount of the then outstanding Notes, and any existing default or compliance with any provision of the Indenture, the Guarantees or the Notes may
be waived with the consent of the Holders of a majority in aggregate principal amount of the then outstanding Notes. Without the consent of any Holder of a Note, the Indenture, the Guarantees or the
Notes may be amended or supplemented to cure any ambiguity, defect or inconsistency, to provide for uncertificated Notes in addition to or in place of certificated Notes, to provide for the assumption
of an Issuer's or a Subsidiary Guarantor's obligations to Holders of the Notes in case of a merger or consolidation or sale of all or substantially all of such Issuer's assets, to add or release
Subsidiary Guarantors pursuant to the terms of the Indenture, to make any change that would provide any additional rights or benefits to the Holders of the Notes or surrender any right or power
conferred upon the Issuers or the Subsidiary Guarantors by the Indenture that does not adversely affect the rights under the Indenture of any such 

Exhibit A, Page 6

 

Holder,
to provide for the issuance of additional Notes in accordance with the limitations set forth in the Indenture, to comply with the requirements of the SEC in order to effect or maintain the
qualification of the Indenture under the Trust Indenture Act, to evidence or provide for the acceptance of appointment under the Indenture of a successor Trustee, to add additional Events of Default
or to secure the Notes and/or the Guarantees. 

        12.   Defaults
and Remedies. Events of Default include in summary form: (i) default for 30 days in the payment when due of interest on, including Additional
Interest, if any, with respect to, the Notes; (ii) default in payment when due of the principal of or premium, if any, on the Notes; (iii) failure by the Partnership or any of its
Restricted Subsidiaries to comply with Section 5.01 of the Indenture; (iv) failure by the Partnership to comply with the provisions described under Section 3.09, 4.06, 4.07, 4.08,
4.09, 4.10, 4.11. 4.12, 4.13, 4.14, 4.15, 4.16, 4.17 or 4.18 of the Indenture for 30 days after notice to the Issuers by the Trustee or to the Issuers and Trustee by Holders of at least 25% in
aggregate principal amount of the Notes then outstanding (provided that no such notice need be given, and an Event of Default shall occur, 30 days after a failure to comply with the covenants
in Section 4.08 or 4.09 of the Indenture, unless theretofore cured), in each case other than a failure to purchase Notes which will constitute an Event of Default under
clause (ii) above; (v) failure by the Partnership to comply with any of its other agreements in the Indenture for 60 days after notice to the Issuers by the Trustee or to
the Issuers and Trustee by Holders of at least 25% in aggregate principal amount of the Notes then outstanding; (vi) default under any mortgage, indenture or instrument under which there may be
issued or by which there may be secured or evidenced any Indebtedness for money borrowed by an Issuer or any Restricted Subsidiary of the Partnership (or the payment of which is guaranteed by an
Issuer or any Restricted Subsidiary of the Partnership), whether such Indebtedness or guarantee now exists, or is created after the date of the Indenture, if that default (a) is caused by a
failure to pay principal of or premium, if any, or interest on such Indebtedness prior to the expiration of the grace period provided in such Indebtedness on the date of such default (a "Payment
Default") or (b) results in the acceleration of such Indebtedness prior to its express maturity and, in each case, the principal amount of any such Indebtedness, together with the principal
amount of any other such Indebtedness under which there has been a Payment Default or the maturity of which has been so accelerated, aggregates $10.0 million or more; (vii) the failure
by an Issuer or any Restricted Subsidiary of the Partnership to pay final judgments by courts of competent jurisdiction aggregating in excess of $10.0 million, which judgments are not paid,
discharged or stayed for a period of 60 days; (viii) except as permitted by the Indenture, any Guarantee of a Subsidiary Guarantor shall be held in any judicial proceeding to be
unenforceable or invalid or shall cease for any reason to be in full force and effect or any Subsidiary Guarantor, or any Person acting on behalf of any Subsidiary Guarantor, shall deny or disaffirm
its obligations under its Guarantee; and (ix) certain events of bankruptcy or insolvency with respect to an Issuer or any Restricted Subsidiary of the Partnership that is a Significant
Subsidiary or any group of Restricted Subsidiaries that, taken as a whole, would constitute a Significant Subsidiary. If any Event of Default occurs and is continuing, the Trustee may or at the
request of the Holders of at least 25% in aggregate principal amount of the then outstanding Notes shall declare all the Notes to be due and payable. Notwithstanding the foregoing, in the case of an
Event of Default arising from certain events of bankruptcy or insolvency, with respect to an Issuer, all outstanding Notes will become due and payable without further action or notice. Holders may not
enforce the Indenture or the Notes except as provided in the Indenture. Subject to certain limitations, Holders of a majority in aggregate principal amount of the then outstanding Notes may direct the
Trustee in its exercise of any trust or power. The Trustee may withhold from Holders of the Notes notice of any continuing Default or Event of Default (except a Default or Event of Default relating to
the payment of principal or interest) if it determines that withholding notice is in their interest. 

        The
Holders of a majority in aggregate principal amount of the Notes then outstanding by notice to the Trustee may on behalf of the Holders of all of the Notes waive any existing Default
or Event of Default and its consequences under the Indenture except a continuing Default or Event of Default in 

Exhibit A, Page 7

 

the
payment of interest (including Additional Interest, if any) on, or the principal or premium, if any, of the Notes. The Issuers and the Subsidiary Guarantors are required to deliver to the Trustee
annually a statement regarding compliance with the Indenture, and the Issuers are required upon becoming aware of any Default or Event of Default, to deliver to the Trustee a statement specifying such
Default or Event of Default. 

        13.   Trustee
Dealings with Partnership. The Trustee, in its commercial banking or any other capacity, may make loans to, accept deposits from, and perform services for the
Partnership or its Affiliates, and may otherwise deal with the Partnership or its Affiliates, as if it were not the Trustee. 

        14.   No
personal liability of directors, officers, employees and unitholders and no recourse against General Partner. Neither the General Partner nor any past, present or
future director, officer, partner, employee, incorporator, manager or unitholder or other owner of Equity Interests of the Issuers, the General Partner or any Subsidiary Guarantor, as such, shall have
any liability for any Obligations of the Issuers or the Subsidiary Guarantors under the Notes, the Indenture or the Guarantees or for any claim based on, in respect of, or by reason of, such
Obligations or their creation. Each Holder by accepting a Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes. 

        15.   Authentication.
This Note shall not be valid until authenticated by the manual signature of the Trustee or an authenticating agent. 

        16.   Abbreviations.
Customary abbreviations may be used in the name of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the entireties),
JT TEN (= joint tenants with right of survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts to Minors Act). 

        17.   Additional
Rights and Obligations of Holders of Restricted Global Notes and Restricted Certificated Notes. In addition to the rights provided to Holders of Notes under
the Indenture, Holders of Restricted Global Notes and Restricted Certificated Notes shall have all the rights and obligations set forth in the Registration Rights Agreement dated as
of                             ,
            , among the Issuers, the Subsidiary Guarantors and the parties named on the signature pages thereof (the
"Registration Rights Agreement"). 

        18.   CUSIP
Numbers. Pursuant to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Issuers have caused CUSIP numbers to be
printed on the Notes and the Trustee may use CUSIP numbers in notices of redemption as a convenience to Holders. No representation is made as to the accuracy of such numbers either as printed on the
Notes or as contained in any notice of redemption and reliance may be placed only on the other identification numbers placed thereon. The Issuers will furnish to any Holder upon written request and
without charge a copy of the Indenture and/or the Registration Rights Agreement. 

        Requests
may be made to: 

MarkWest
Energy Partners, L.P.

155 Inverness Drive West, Suite 200

Englewood, Colorado 80112

Attention: Chief Financial Officer 

Exhibit A, Page 8

 

[FORM
OF ASSIGNMENT] 

        To
assign this Note, fill in the form below: (I) or (we) assign and transfer this Note to: 

(Insert assignee's soc. sec. or tax I.D. no.) 

(Print or type name, address and zip code of assignee) 

	and irrevocably appoint	 	 
	 	 	

to
transfer this Note on the books of the Issuers. The agent may substitute another to act for him. 

	

Date:	
 	

 	
 	

Your Signature:	
 	

 (Sign exactly as name appears on the other side of this Note)

Signature
Guarantee* 

	*
	NOTICE:
The Signature must be guaranteed by an Institution which is a member of one of the following recognized signature Guarantee Programs:

	(i)
	The
Securities Transfer Agent Medallion Program (STAMP); (ii) The New York Stock Exchange Medallion Program (MNSP); (iii) The Stock Exchange Medallion Program (SEMP); or
(iv) in such other guarantee program acceptable to the Trustee. 

Exhibit A, Page 9

 

OPTION OF HOLDER TO ELECT PURCHASE  

        If you want to elect to have this Note purchased by the Issuers pursuant to Sections 3.09 and 4.07 or Section 4.06 of the Indenture, check the box
below: 

	o    Sections 3.09 and 4.07	 	o    Section 4.06

        If
you want to elect to have only part of the Note purchased by the Issuers pursuant to Sections 3.09 and 4.07 or Section 4.06 of the Indenture, state the amount you
elect to have purchased (must be an integral multiple of $1,000): 

$

	

Date:	
 	

 	
 	

Your Signature:	
 	

	

Date:	
 	

 	
 	

Your Signature:	
 	

 (Sign exactly as name appears on the other side of this Note)

Signature
Guarantee* 

	*
	NOTICE:
The Signature must be guaranteed by an Institution which is a member of one of the following recognized signature Guarantee Programs:

	(i)
	The
Securities Transfer Agent Medallion Program (STAMP); (ii) The New York Stock Exchange Medallion Program (MNSP); (iii) The Stock Exchange Medallion Program (SEMP); or
(iv) in such other guarantee program acceptable to the Trustee. 

Exhibit A, Page 10

 

SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE*  

        The following exchanges of a part of this Global Note for an interest in another Global Note or for a Certificated Note, or exchanges of a part of
another Global Note or Certificated Note for an interest in this Global Note, have been made: 

	Date of Exchange
 
	 	Signature of authorized signatory of Trustee or Note Custodian
	 	Amount of decrease in Principal amount of this Global Note
	 	Amount of increase in Principal amount of this Global Note
	 	Principal amount of this Global Note following such decrease or increase

	*
	This
schedule should only be included if the Note is issued in global form. 

Exhibit A, Page 11

   EXHIBIT B  

FORM OF CERTIFICATE OF TRANSFER  

Wells
Fargo Bank, National Association

505 Main Street, Suite 301

Fort Worth, Texas 76102

Attention: Corporate Trust Department 

	Re:
	6.875%
Senior Notes due 2014 of MarkWest Energy Partners, L.P. and MarkWest Energy Finance Corporation 

        Reference
is hereby made to the Indenture, dated as of October 25, 2004 (the "Indenture"), among MarkWest Energy Partners, L.P. and MarkWest Energy Finance Corporation, as issuers
(the "Issuers"), the Persons acting as guarantors and named therein (the "Subsidiary Guarantors") and Wells Fargo Bank, National Association, as trustee. Capitalized terms used but not defined herein
shall have the meanings given to them in the Indenture. 

                                ,
(the "Transferor") owns and proposes to transfer the Note[s] or interest in such Note[s] specified in Annex A hereto, in
the principal amount of $                        in such Note[s] or interests (the "Transfer"),
to                        (the "Transferee"), as further specified in Annex A hereto. In
connection with the Transfer, the Transferor hereby certifies that: 

[CHECK
ALL THAT APPLY] 

        1.     o    Check
if Transferee will take delivery of a beneficial interest in the 144A Global Note or a
Certificated Note Pursuant to Rule 144A. The Transfer is being effected pursuant to and in accordance with Rule 144A under the United States Securities Act of 1933, as amended
(the "Securities Act"), and, accordingly, the Transferor hereby further certifies that the beneficial interest or Certificated Note is being transferred to a Person that the Transferor
reasonably believed and believes is purchasing the beneficial interest or Certificated Note for its own account, or for one or more accounts with respect to which such Person exercises sole
investment discretion, and such Person and each such account is a "qualified institutional buyer" within the meaning of Rule 144A in a transaction meeting the requirements of Rule 144A
and such Transfer is in compliance with any applicable blue sky securities laws of any state of the United States. Upon consummation of the proposed Transfer in accordance with the terms of the
Indenture, the transferred beneficial interest or Certificated Note will be subject to the restrictions on transfer enumerated in the Private Placement Legend printed on the 144A Global
Note and/or the Certificated Note and in the Indenture and the Securities Act. 

        2.     o    Check
if Transferee will take delivery of a beneficial interest in the Regulation S Global
Note or a Certificated Note pursuant to Regulation S. The Transfer is being effected pursuant to and in accordance with Rule 903 or Rule 904 under the Securities Act and,
accordingly, the Transferor hereby further certifies that (i) the Transfer is not being made to a person in the United States and (x) at the time the buy order was originated, the
Transferee was outside the United States or such Transferor and any Person acting on its behalf reasonably believed and believes that the Transferee was outside the United States or (y) the
transaction was executed in, on or through the facilities of a designated offshore securities market and neither such Transferor nor any Person acting on its behalf knows that the transaction was
prearranged with a buyer in the United States, (ii) no directed selling efforts have been made in contravention of the requirements of Rule 903(b) or Rule 904(b) of
Regulation S under the Securities Act, (iii) the transaction is not part of a plan or scheme to evade the registration requirements of the Securities Act, and (iv) if the proposed
transfer is being made prior to the expiration of the Distribution Compliance Period, the transfer is not being made to a U.S. Person or for the account or benefit of a U.S. Person (other than an
Initial Purchaser). Upon consummation 

Exhibit B, Page 1

 

of
the proposed transfer in accordance with the terms of the Indenture, the transferred beneficial interest or Certificated Note will be subject to the restrictions on Transfer enumerated in
the Private Placement Legend printed on the Regulation S Global Note and/or the Certificated Note and in the Indenture and the Securities Act. 

        3.     o    Check
and complete if Transferee will take delivery of a beneficial interest in the Restricted Global
Note or a Certificated Note pursuant to any provision of the Securities Act other than Rule 144A or Regulation S. The Transfer is being effected in compliance with the
transfer restrictions applicable to beneficial interests in Restricted Global Notes and Restricted Certificated Notes and pursuant to and in accordance with the Securities Act and any applicable blue
sky securities laws of any state of the United States, and accordingly the Transferor hereby further certifies that (check one): 

        (a)   o    such
Transfer is being effected pursuant to and in accordance with Rule 144 under the Securities Act;
or 

        (b)   o    such
Transfer is being effected to the Partnership, MarkWest Finance or a Subsidiary of the Partnership; or 

        (c)   o    such
Transfer is being effected to an Institutional Accredited Investor and pursuant to an exemption from
the registration requirements of the Securities Act other than Rule 144A, Rule 144 or Rule 904, and the Transferor hereby further certifies that the Transfer complies with the
transfer restrictions applicable to beneficial interests in a Restricted Global Note or Restricted Certificated Notes and the requirements of the exemption claimed, which certification is
supported by (1) a certificate executed by the Transferee in the form of Exhibit E to the Indenture and (2) an Opinion of Counsel provided by the Transferor or the Transferee (a
copy of which the Transferor has attached to this certification), to the effect that such Transfer is in compliance with the Securities Act. Upon consummation of the proposed transfer in accordance
with the terms of the Indenture, the transferred beneficial interest or Certificated Note will be subject to the restrictions on transfer enumerated in the Private Placement Legend printed on
the Restricted Global Note and/or the Certificated Notes and in the Indenture and the Securities Act. 

        4.     o    Check
if Transferee will take delivery of a beneficial interest in an Unrestricted Global Note or of
an Unrestricted Certificated Note. 

        (a)   o    Check
if Transfer is pursuant to Rule 144. (i) The Transfer is being effected pursuant to and
in accordance with Rule 144 under the Securities Act and in compliance with the transfer restrictions contained in the Indenture and any applicable blue sky securities laws of any state of the
United States and (ii) the restrictions on transfer contained in the Indenture and the Private Placement Legend are not required in order to maintain compliance with the Securities Act. Upon
consummation of the proposed Transfer in accordance with the terms of the Indenture, the transferred beneficial interest or Certificated Note will no longer be subject to the restrictions on
transfer enumerated in the Private Placement Legend printed on the Restricted Global Notes, on Restricted Certificated Notes and in the Indenture. 

        (b)   o    Check
if Transfer is Pursuant to Regulation S. (i) The Transfer is being effected pursuant to
and in accordance with Rule 903 or Rule 904 under the Securities Act and in compliance with the transfer restrictions contained in the Indenture and any applicable blue sky securities
laws of any state of the United States and (ii) the restrictions on transfer contained in the Indenture and the Private Placement Legend are not required in order to maintain compliance with
the Securities Act. Upon consummation of the proposed Transfer in accordance with the terms of the Indenture, the transferred beneficial interest or Certificated Note will no longer be subject
to the restrictions on transfer enumerated in the Private Placement Legend printed on the Restricted Global Notes, on Restricted Certificated Notes and in the Indenture. 

Exhibit B, Page 2

 

        (c)   o    Check
if Transfer is Pursuant to Other Exemption. (i) The Transfer is being effected pursuant to and
in compliance with an exemption from the registration requirements of the Securities Act other than Rule 144, Rule 903 or Rule 904 and in compliance with the transfer restrictions
contained in the Indenture and any applicable blue sky securities laws of any state of the United States and (ii) the restrictions on transfer contained in the Indenture and the Private
Placement Legend are not required in order to maintain compliance with the Securities Act. Upon consummation of the proposed Transfer in accordance with the terms of the Indenture, the transferred
beneficial interest or Certificated Note will not be subject to the restrictions on transfer enumerated in the Private Placement Legend printed on the Restricted Global Notes or Restricted
Certificated Notes and in the Indenture. 

        (d)   o    Check
if Transfer is Pursuant to an Effective Registration Statement. The transfer is being effected
pursuant to an effective registration statement under the Securities Act and in compliance with the prospectus delivery requirements of the Securities Act. Upon consummation of the proposed Transfer
in accordance with the terms of the Indenture, the transferred beneficial interest or Certificated Note will not be subject to the restrictions on transfer enumerated in the Private Placement
Legend printed on the Restricted Global Notes or Restricted Certificated Notes and in the Indenture. 

        This certificate and the statements contained herein are made for your benefit and for the benefit of the Issuers, the Subsidiary Guarantors and [J.P.
Morgan Securities Inc., RBC Capital Markets Corporation, Fortis Securities LLC, Jefferies & Company, Inc., Lehman Brothers Inc., Piper Jaffray & Co., SG Americas
Securities, LLC and Wachovia Capital Markets, LLC] (collectively, the "Initial Purchasers"), the Initial Purchasers of such Notes being transferred. We acknowledge that you, the Issuers,
the Subsidiary Guarantors and the Initial Purchasers will rely upon our confirmations, acknowledgments and agreements set forth herein, and we agree to notify you promptly in writing if any of our
representations or warranties herein ceases to be accurate and complete. 

	

[Insert Name of Transferor]	
 	

 
	

By:	
 	

	
 	

 
	Name:	 	 	 	 
	 	 	
	 	 
	Title:	 	 	 	 
	 	 	
	 	 

Dated:                        ,        

	cc:
	Issuers

Initial
Purchasers 

Exhibit B, Page 3

 
ANNEX A TO CERTIFICATE OF TRANSFER  

	1.
	The
Transferor owns and proposes to transfer the following: 

[CHECK
ONE OF (a) OR (b)] 

	(a)
	o    a
beneficial interest in the:

	(i)
	o    144A
Global Note (CUSIP            ), or

	(ii)
	o    Regulation S
Global Note (CUSIP            ), or

	(iii)
	o    IAI
Global Note (CUSIP            ); or

	(b)
	o    a
Restricted Certificated Note.

	2.
	After
the Transfer the Transferee will hold: 

[CHECK ONE] 

	(a)
	o    a
beneficial interest in the:

	(i)
	o    144A
Global Note (CUSIP            ), or

	(ii)
	o    Regulation S
Global Note (CUSIP            ), or

	(iii)
	o    IAI
Global Note (CUSIP            ), or

	(iv)
	o    Unrestricted
Global Note (CUSIP            ); or

	(b)
	o    a
Restricted Certificated Note; or

	(c)
	o    an
Unrestricted Certificated Note, in accordance with the terms of the Indenture. 

Exhibit B, Page 4

   EXHIBIT C  

FORM OF CERTIFICATE OF EXCHANGE  

Wells
Fargo Bank, National Association

505 Main Street, Suite 301

Fort Worth, Texas 76102

Attention: Corporate Trust Department 

	Re:
	6.875%
Senior Notes due 2014 of MarkWest Energy Partners, L.P. and MarkWest Energy Finance Corporation 

(CUSIP                        )

        Reference
is hereby made to the Indenture, dated as of October 25, 2004 (the "Indenture"), among MarkWest Energy Partners, L.P. and MarkWest Energy Finance Corporation, as issuers
(the "Issuers"), the Persons acting as guarantors and named therein (the "Subsidiary Guarantors") and Wells Fargo Bank, National Association, as trustee. Capitalized terms used but not defined herein
shall have the meanings given to them in the Indenture. 

                                (the
"Owner") owns and proposes to exchange the Note[s] or interest in such Note[s] specified herein, in the principal
amount of $                        in such Note[s] or interests (the "Exchange"). In connection with the Exchange, the Owner
hereby certifies that: 

        1.     Exchange
of Restricted Certificated Notes or Beneficial Interests in a Restricted Global Note for Unrestricted Certificated Notes or Beneficial Interests in an
Unrestricted Global Note 

        (a)   o    Check
if Exchange is from beneficial interest in a Restricted Global Note to beneficial interest in
an Unrestricted Global Note. In connection with the Exchange of the Owner's beneficial interest in a Restricted Global Note for a beneficial interest in an Unrestricted Global Note in an
equal principal amount, the Owner hereby certifies (i) the beneficial interest is being acquired for the Owner's own account without transfer, (ii) such Exchange has been effected in
compliance with the transfer restrictions applicable to the Global Notes and pursuant to and in accordance with the United States Securities Act of 1933, as amended (the "Securities Act"),
(iii) the restrictions on transfer contained in the Indenture and the Private Placement Legend are not required in order to maintain compliance with the Securities Act and (iv) the
beneficial interest in an Unrestricted Global Note is being acquired in compliance with any applicable blue sky securities laws of any state of the United States. 

        (b)   o    Check
if Exchange is from Restricted Certificated Note to Unrestricted Certificated Note. In
connection with the Owner's Exchange of a Restricted Certificated Note for an Unrestricted Certificated Note, the Owner hereby certifies (i) the Unrestricted Certificated Note is being
acquired for the Owner's own account without transfer, (ii) such Exchange has been effected in compliance with the transfer restrictions applicable to Restricted Certificated Notes and pursuant
to and in accordance with the Securities Act, (iii) the restrictions on transfer contained in the Indenture and the Private Placement Legend are not required in order to maintain compliance
with the Securities Act and (iv) the Unrestricted Certificated Note is being acquired in compliance with any applicable blue sky securities laws of any state of the United States. 

        This certificate and the statements contained herein are made for your benefit and the benefit of the Issuers, the Subsidiary Guarantors and J.P. Morgan
Securities Inc., RBC Capital Markets Corporation, Fortis Securities LLC, Jefferies & Company, Inc., Lehman Brothers Inc., Piper Jaffray & Co., SG Americas
Securities, LLC and Wachovia Capital Markets, LLC (collectively, the "Initial Purchasers"), the Initial Purchasers of such Notes being transferred. We acknowledge that you, the 

Exhibit C, Page 1

 

Issuers,
the Subsidiary Guarantors and the Initial Purchasers will rely upon our confirmations, acknowledgments and agreements set forth herein, and we agree to notify you promptly in writing if any
of our representations or warranties herein ceases to be accurate and complete. 

	

[Insert Name of Owner]	
 	

 
	

By:	
 	

	
 	

 
	Name:	 	 	 	 
	 	 	
	 	 
	Title:	 	 	 	 
	 	 	
	 	 

Dated:                        ,        

	cc:
	Issuers

Initial
Purchasers 

Exhibit C, Page 2

   EXHIBIT D  

FORM OF GUARANTEE NOTATION  

        Subject to the limitations set forth in the Indenture (the "Indenture") referred to in the Note upon which this notation is endorsed, each of the entities
listed on Schedule A thereto (hereinafter referred to as the "Subsidiary Guarantors," which term includes any successor or additional Subsidiary Guarantor under the Indenture) (i) has
unconditionally guaranteed: (a) the due and punctual payment of the principal of, premium and interest (including Additional Interest, if any) on the Notes, whether at maturity or interest
payment date, by acceleration, call for redemption or otherwise, (b) the due and punctual payment of interest on the overdue principal of, premium and interest (including Additional Interest,
if any) if lawful, on the Notes, (c) the due and punctual payment or performance of all other Obligations of the Issuers to the Holders or the Trustee, all in accordance with the terms set
forth in the Indenture, and (d) in case of any extension of time of payment or renewal of any Notes or any of such other Obligations, the prompt payment in full thereof when due or performance
thereof in accordance with the terms of the extension or renewal, whether at Stated Maturity, by acceleration or otherwise and (ii) has agreed to pay any and all costs and expenses (including
reasonable attorneys' fees) incurred by the Trustee or any Holder in enforcing any rights under this Guarantee. 

        This
Guarantee Notation is subject to the limitations set forth in the Indenture, including Article 10 thereof. 

        No
member, manager, stockholder, partner, officer, employee, director or incorporator, as such, past, present or future, of the Subsidiary Guarantors shall have any personal liability
under this Guarantee by reason of his or its status as such member, manager, partner, stockholder, officer, employee, director or incorporator. 

        The
Guarantee shall be binding upon each Subsidiary Guarantor and its successors and assigns and shall inure to the benefit of the successors and assigns of the Trustee and the Holders
and, in the event of any transfer or assignment of rights by any Holder or the Trustee, the rights and privileges herein conferred upon that party shall automatically extend to and be vested in such
transferee or assignee, all subject to the terms and conditions hereof. 

        Each
Guarantee shall not be valid or obligatory for any purpose until the certificate of authentication on the Note upon which this notation of Guarantee is noted shall have been
executed by the Trustee under the Indenture by the manual signature of one of its authorized officers. 

        The
Subsidiary Guarantors may be released from their Guarantees upon the terms and subject to the conditions provided in the Indenture. 

Exhibit D, Page 1

 

	

 	
 	

Subsidiary Guarantors:
	

 	
 	

MARKWEST ENERGY OPERATING COMPANY, L.L.C.

BASIN PIPELINE L.L.C.

WEST SHORE PROCESSING COMPANY, L.L.C.

MARKWEST ENERGY APPALACHIA, L.L.C.

MARKWEST TEXAS GP, L.L.C.

MW TEXAS LIMITED, L.L.C.

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C.

MARKWEST WESTERN OKLAHOMA GAS COMPANY, L.L.C.
	

 	
 	

By:	
 	

	 	 	Name:	 	 
	 	 	Title:	 	 
	

 	
 	

MARKWEST POWER TEX L.P.

MARKWEST PINNACLE L.P.

MARKWEST PNG UTILITY L.P.

MARKWEST TEXAS PNG UTILITY L.P.

MARKWEST BLACKHAWK L.P.

MARKWEST NEW MEXICO L.P.

MARKWEST ENERGY EAST TEXAS GAS COMPANY L.P.
	

 	
 	

By:	
 	

MARKWEST TEXAS GP, L.L.C., its general partner
	

 	
 	

 	
 	

By:	
 	

	 	 	 	 	Name:	 	 
	 	 	 	 	Title:	 	 

Exhibit D, Page 2

   EXHIBIT E  

FORM OF CERTIFICATE FROM

ACQUIRING INSTITUTIONAL ACCREDITED INVESTOR  

MarkWest
Energy Partners, L.P.

MarkWest Energy Finance Corporation

155 Inverness Drive West, Suite 200

Englewood, Colorado 80112 

Wells
Fargo Bank, National Association

505 Main Street, Suite 301

Fort Worth, Texas 76102

Attention: Corporate Trust Department 

	Re:
	6.875%
Senior Notes due 2014 issued by MarkWest Energy Partners, L.P. and MarkWest Energy Finance Corporation 

        Reference
is hereby made to the Indenture, dated as of October 25, 2004 (the "Indenture"), among MarkWest Energy Partners, L.P. (the "Partnership") and MarkWest Energy Finance
Corporation ("MarkWest Finance"), as issuers (the "Issuers"), the Subsidiaries named therein, as Subsidiary
Guarantors, and Wells Fargo Bank, National Association, as trustee. Capitalized terms used but not defined herein shall have the meanings given to them in the Indenture. 

        In
connection with our proposed purchase of $                        aggregate principal amount of: 

	(a)
	o    a
beneficial interest in a Global Note, or

	(b)
	o    a
Certificated Note, 

        we
confirm that: 

        1.     We
understand that any subsequent transfer of the Series A Notes or any interest therein is subject to certain restrictions and conditions set forth in the
Indenture and the undersigned agrees to be bound by, and not to resell, pledge or otherwise transfer the Series A Notes or any interest therein except in compliance with, such restrictions and
conditions and the United States Securities Act of 1933, as amended (the "Securities Act"). 

        2.     We
understand that the offer and sale of the Series A Notes have not been registered under the Securities Act, and that the Series A Notes and any interest
therein may not be offered or sold except as permitted in the following sentence. We agree, on our own behalf and on behalf of any accounts for which we are acting as hereinafter stated, that if we
should sell the Series A Notes or any interest therein, we will do so only (A) to the Partnership, MarkWest Finance, or any subsidiary of the Partnership, (B) in the United States
to a person who the seller reasonably believes is a "qualified institutional buyer" (as defined in Rule 144A under the Securities Act) in a transaction meeting the requirements of
Rule 144A, (C) outside the United States in an offshore transaction in accordance with Rule 904 under the Securities Act, (D) pursuant to an exemption from registration
under the Securities Act provided by Rule 144 thereunder (if available), (E) to an institutional "accredited investor" within the meaning of Rule 501(A)(1), (2), (3) or
(7) under the Securities Act that is an institutional accredited investor acquiring the security for its own account or for the account of such institutional accredited investor, in each case
in a minimum principal amount of the securities of $250,000, for investment purposes and not with a view to or for offer or sale in connection with any distribution in violation of the Securities Act
or (F) pursuant to an effective registration statement under the Securities Act, in each of cases (A) through (E) in accordance with any applicable securities laws of any state of
the United States, and we further agree to provide to any person purchasing a Certificated 

Exhibit E, Page 1

 

Note or
beneficial interest in a Global Note from us in a transaction meeting the requirements of clauses (B) through (E) of this paragraph a notice advising such
purchaser that resales thereof are restricted as stated herein. 

        3.     We
understand that, on any proposed resale of the Series A Notes or beneficial interest therein, we will be required to furnish to you such certifications, legal
opinions and other information as you may reasonably requires to confirm that the proposed sale complies with the foregoing restrictions. We further understand that the Series A Notes purchased
by us will bear a legend to the foregoing effect. 

        4.     We
are an institutional "accredited investor" (as defined in Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and
have such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of our investment in the Series A Notes, and we and any accounts for
which we are acting are each able to bear the economic risk of our or its investment. We are acquiring the Series A Notes for investment purposes and not with a view to, or for offer or sale in
connection with, any distribution in violation of the Securities Act. 

        5.     We
are acquiring the Series A Notes or beneficial interest therein purchased by us for our own account or for one or more accounts (each of which is an
institutional "accredited investor") as to each of which we exercise sole investment discretion. 

        You
are entitled to rely upon this letter and are irrevocably authorized to produce this letter or a copy hereof to any interested party in any administrative or legal proceedings or
official inquiry with respect to the matters covered hereby. 

	

 	
 	

[Insert Name of Institutional Accredited Investor]
	

 	
 	

By:	
 	

	 	 	Name:	 	 
	 	 	Title:	 	 

Dated:                        ,        

Exhibit E, Page 2

   ANNEX A  

MARKWEST ENERGY PARTNERS, L.P.  

 MARKWEST ENERGY FINANCE CORPORATION  

 and  

 the Subsidiary Guarantors named herein  

 6.875% SENIOR NOTES DUE 2014  

 FORM OF SUPPLEMENTAL INDENTURE  

 DATED AS OF                        ,        

 WELLS FARGO BANK, NATIONAL ASSOCIATION,  

 Trustee  

A-1

   
        This SUPPLEMENTAL INDENTURE, dated as
of                            ,            is
among MarkWest Energy Partners, L.P., a Delaware limited partnership (the "Partnership"),
MarkWest Energy Finance Corporation, a Delaware corporation ("MarkWest Finance" and, together with the Partnership, the "Issuers"), each of the parties identified under the caption "Subsidiary
Guarantors" on the signature page hereto (the "Subsidiary Guarantors") and Wells Fargo Bank, National Association, a national banking association, as Trustee. 

RECITALS  

        WHEREAS, the Issuers, the initial Subsidiary Guarantors and the Trustee entered into an Indenture, dated as of October 25, 2004 (the "Indenture"), pursuant
to which the Issuers have issued $                        in principal amount of 6.875% Senior Notes due 2014 (the "Notes");

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

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

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

ARTICLE 1  

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

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

ARTICLE 2  

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

ARTICLE 3  

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

        Section 3.02.
Except as otherwise expressly provided herein, no duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason
of this Supplemental Indenture. This Supplemental Indenture is executed and accepted by the Trustee subject to all the terms and conditions set forth in the Indenture with the same force and effect as
if those terms and conditions were repeated at length herein and made applicable to the Trustee with respect hereto. 

A-2

 

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

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

[NEXT
PAGE IS SIGNATURE PAGE] 

A-3

 

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

	

 	
 	
MARKWEST ENERGY PARTNERS, L.P.
	

 	
 	

BY:	
 	

MARKWEST ENERGY GP, L.L.C., ITS GENERAL PARTNER
	
 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
MARKWEST ENERGY FINANCE CORPORATION
	
 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
SUBSIDIARY GUARANTORS
	

 	
 	

[                                         
       ]
	
 	
 	

By:	
 	

 Name:

Title:
	

 	
 	
WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
	
 	
 	

By:	
 	

 Name:

Title:

A-4

   REGISTRATION RIGHTS AGREEMENT  

Exhibit E, Page 1

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Exhibit 4.3  

EXECUTION COPY  

October 25,
2004 

 
 

REGISTRATION RIGHTS AGREEMENT    
    

        This REGISTRATION RIGHTS AGREEMENT dated October 25, 2004 (the "Agreement") is entered into by and among MarkWest Energy Partners L.P., a limited
partnership organized under the laws of the State of Delaware (the "Partnership"), MarkWest Energy Finance Corporation, a corporation organized under the laws of the State of Delaware ("Finance Corp"
and, together with the Partnership, the "Issuers"), the guarantors listed in Schedule 1 hereto (the "Guarantors"), and J.P. Morgan Securities Inc. ("JPMorgan"), RBC Capital Markets
Corporation, Fortis Securities LLC, Jefferies & Company, Inc., Lehman Brothers Inc., Piper Jaffrey & Co., SG Americas Securities, LLC and Wachovia Capital Markets
(collectively, the "Initial Purchasers"). 

        The
Issuers, the Guarantors and the Initial Purchasers are parties to the Purchase Agreement dated October 19, 2004 (the "Purchase Agreement"), which provides for the sale by the
Issuers to the Initial Purchasers of $225,000,000 aggregate principal amount of the Issuers' 6.875% Senior Notes due 2014 (the "Securities") which will be guaranteed on an unsecured senior basis by
each of the Guarantors. As an inducement to the Initial Purchasers to enter into the Purchase Agreement, the Issuers and the Guarantors have agreed to provide to the Initial Purchasers and their
direct and indirect transferees the registration rights set forth in this Agreement. The execution and delivery of this Agreement is a condition to the closing under the Purchase Agreement. 

        In
consideration of the foregoing, the parties hereto agree as follows: 

        1.    Definitions.    As used in this Agreement, the following terms shall have the following meanings: 

        "Business
Day" shall have the meaning ascribed thereto in the Indenture. 

        "Closing
Date" shall mean the Closing Date as defined in the Purchase Agreement. 

        "DTC"
shall mean the Depository Trust Company. 

        "Exchange
Act" shall mean the Securities Exchange Act of 1934, as amended from time to time. 

        "Exchange
Dates" shall have the meaning set forth in Section 2(a)(ii) hereof. 

        "Exchange
Offer" shall mean the exchange offer by the Issuers and the Guarantors of Exchange Securities for Registrable Securities pursuant to Section 2(a) hereof. 

        "Exchange
Offer Registration" shall mean a registration under the Securities Act effected pursuant to Section 2(a) hereof. 

        "Exchange
Offer Registration Statement" shall mean an exchange offer registration statement on Form S-4 (or, if applicable, on another appropriate form) and all
amendments and supplements to such registration statement, in each case including the Prospectus contained therein, all exhibits thereto and any document incorporated by reference therein. 

        "Exchange
Securities" shall mean senior notes issued by the Issuers and guaranteed by the Guarantors under the Indenture containing terms identical to the Securities (except that the
Exchange Securities will not be subject to restrictions on transfer or to any increase in annual interest rate for failure to comply with this Agreement) and to be offered to Holders of Securities in
exchange for Securities pursuant to the Exchange Offer. 

        "Finance
Corp" shall have the meaning set forth in the preamble and shall also include Finance Corp's successors. 

 

        "Guarantors"
shall have the meaning set forth in the preamble and shall also include any Guarantor's successors. 

        "Holders"
shall mean the Initial Purchasers, for so long as they own any Registrable Securities, and each of their successors, assigns and direct and indirect transferees who become
owners of Registrable Securities under the Indenture; provided that for purposes of Sections 4 and 5 of this Agreement, the term "Holders" shall include Participating Broker-Dealers 

        "Indenture"
shall mean the Indenture relating to the Securities dated as of October 25, 2004 among the Issuers, the Guarantors and Wells Fargo Bank, National Association, as
trustee, and as the same may be amended from time to time in accordance with the terms thereof. 

        "Initial
Purchasers" shall have the meaning set forth in the preamble. 

        "Inspector"
shall have the meaning set forth in Section 3(a)(xiii) hereof. 

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

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

        "Majority
Holders" shall mean the Holders of a majority of the aggregate principal amount of the outstanding Registrable Securities; provided that whenever the consent or approval of
Holders of a specified percentage of Registrable Securities is required hereunder, any Registrable Securities owned directly or indirectly by the Issuers or any of their affiliates shall not be
counted in determining whether such consent or approval was given by the Holders of such required percentage or amount;
and provided, further, that if the Issuers shall issue any additional Securities under the Indenture prior to consummation of the Exchange Offer or, if applicable, the effectiveness of any Shelf
Registration Statement, such additional Securities and the Registrable Securities to which this Agreement relates shall be treated together as one class for purposes of determining whether the consent
or approval of Holders of a specified percentage of Registrable Securities has been obtained. 

        "Participating
Broker-Dealers" shall have the meaning set forth in Section 4(a) hereof. 

        "Partnership"
shall have the meaning set forth in the preamble and shall also include the Partnership's successors. 

        "Person"
shall mean an individual, partnership, limited liability company, corporation, trust or unincorporated organization, or a government or agency or political subdivision thereof. 

        "Prospectus"
shall mean the prospectus included in a Registration Statement, including any preliminary prospectus, and any such prospectus as amended or supplemented by any prospectus
supplement, including a prospectus supplement with respect to the terms of the offering of any portion of the Registrable Securities covered by a Shelf Registration Statement, and by all other
amendments and supplements to such prospectus, and in each case including any document incorporated by reference therein. 

        "Purchase
Agreement" shall have the meaning set forth in the preamble. 

        "Registrable
Securities" shall mean the Securities; provided that the Securities shall cease to be Registrable Securities (i) when a Registration Statement with respect to such
Securities has been declared effective under the Securities Act and such Securities have been exchanged or disposed of pursuant to such Registration Statement, (ii) when such Securities are
eligible to be sold pursuant to Rule 144(k) (or any similar provision then in force, but not Rule 144A) under the Securities Act or (iii) when such Securities cease to be
outstanding. 

        "Registration
Expenses" shall mean any and all expenses incident to performance of or compliance by the Issuers and the Guarantors with this Agreement, including without 

2

 

limitation:(i) all
SEC, stock exchange or National Association of Securities Dealers, Inc. registration and filing fees, (ii) all fees and expenses incurred in connection with
compliance with state securities or blue sky laws (including reasonable fees and disbursements of counsel for any Underwriters or Holders in connection with blue sky qualification of any Exchange
Securities or Registrable Securities), (iii) all expenses of any Persons in preparing or assisting in preparing, word processing, printing and distributing any Registration Statement, any
Prospectus and any amendments or supplements thereto, any underwriting agreements, securities sales agreements or other similar agreements and any other documents relating to the performance of and
compliance with this Agreement, (iv) all rating agency fees, (v) all fees and disbursements relating to the qualification of the Indenture under applicable securities laws,
(vi) the fees and disbursements of the Trustee and its counsel, (vii) the fees and disbursements of counsel for the Issuers and the Guarantors and, in the case of a Shelf Registration
Statement, the fees and disbursements of one counsel for the Holders (which counsel shall be selected by the Majority Holders and which counsel may also be counsel for the Initial Purchasers) and
(viii) the fees and disbursements of the independent public accountants of the Issuers and the Guarantors, including the expenses of any special audits or "comfort" letters required by or
incident to the performance of and compliance with this Agreement, but excluding fees and expenses of counsel to the Underwriters (other than fees and expenses set forth in
clause (ii) above) or the Holders and underwriting discounts and commissions, brokerage commissions and transfer taxes, if any, relating to the sale or disposition of Registrable
Securities by a Holder. 

        "Registration
Statement" shall mean any registration statement of the Issuers and the Guarantors that covers any of the Exchange Securities or Registrable Securities pursuant to the
provisions of this Agreement and all amendments and supplements to any such registration statement, including post-effective amendments, in each case including the Prospectus contained
therein, all exhibits thereto and any document incorporated by reference therein. 

        "SEC"
shall mean the United States Securities and Exchange Commission. 

        "Securities
Act" shall mean the Securities Act of 1933, as amended from time to time. 

        "Shelf
Effectiveness Period" shall have the meaning set forth in Section 2(b) hereof. 

        "Shelf
Registration" shall mean a registration effected pursuant to Section 2(b) hereof. 

        "Shelf
Registration Statement" shall mean a "shelf" registration statement of the Issuers and the Guarantors that covers all or a portion of the Registrable Securities (but no other
securities unless approved by the Holders of a majority of the Registrable Securities to be covered by such Shelf Registration Statement) on an appropriate form under Rule 415 under the
Securities Act, or any similar rule that may be adopted by the SEC, and all amendments and supplements to such registration statement, including post-effective amendments, in each case
including the Prospectus contained therein, all exhibits thereto and any document incorporated by reference therein. 

        "Staff"
shall mean the staff of the SEC. 

        "Target
Registration Date" shall have the meaning set for in Section 2(d) hereof. 

        "Trust
Indenture Act" shall mean the Trust Indenture Act of 1939, as amended from time to time. 

        "Trustee"
shall mean the trustee with respect to the Securities under the Indenture. 

        "Underwriter"
shall have the meaning set forth in Section 3(e) hereof. 

        "Underwritten
Offering" shall mean an offering in which Registrable Securities are sold to an Underwriter for reoffering to the public. 

3

 

        2.    Registration Under the Securities Act.    (a) To the extent not prohibited by any applicable law or
applicable interpretations of the Staff, the Issuers and the Guarantors shall use their reasonable best efforts to cause to be filed an Exchange Offer Registration Statement covering an offer to the
Holders to exchange all the Registrable Securities for Exchange Securities. The Issuers and the Guarantors shall commence the Exchange Offer promptly after the Exchange Offer Registration Statement is
declared effective by the SEC and use their reasonable best efforts to complete the Exchange Offer not later than 60 days after such effective date. 

        The
Issuers and the Guarantors shall commence the Exchange Offer by mailing the related Prospectus, appropriate letters of transmittal and other accompanying documents to each Holder
stating, in addition to such other disclosures as are required by applicable law, substantially the following: 

	(i)
	that
the Exchange Offer is being made pursuant to this Agreement and that all Registrable Securities validly tendered and not properly withdrawn will be accepted for exchange;

	(ii)
	the
dates of acceptance for exchange (which shall be a period of at least 20 Business Days from the date such notice is mailed) (the "Exchange Dates");

	(iii)
	that
any Registrable Security not tendered will remain outstanding and continue to accrue interest but will not retain any rights under this Agreement;

	(iv)
	that
any Holder electing to have a Registrable Security exchanged pursuant to the Exchange Offer will be required, (x) in the case a Holder electing to exchange a Registrable
Security in global form, to comply with the applicable procedures of DTC for book-entry tenders, and, (y) in the case of a Holder electing to exchange a Registrable Security in
certificated form, to surrender such Registrable Security, together with the appropriate letters of transmittal, to the institution and at the address (located in the Borough of Manhattan, The City of
New York) and in the manner specified in the notice, prior to the close of business on the last Exchange Date; and

	(v)
	that
any Holder will be entitled to withdraw its election, not later than the close of business on the last Exchange Date, by, (x) in the case of a Holder withdrawing its
election to exchange a Registrable Security in global form, complying with the applicable procedures of DTC for withdrawal of tenders, and, (y) in the case of a Holder withdrawing its election
to exchange a Registrable Security in certificated form, sending to the institution and at the address (located in the Borough of Manhattan, The City of New York) specified in the notice, a telegram,
facsimile transmission or letter setting forth the name of such Holder, the principal amount of Registrable Securities delivered for exchange and a statement that such Holder is withdrawing its
election to have such Securities exchanged. 

        As
a condition to participating in the Exchange Offer, a Holder will be required to represent to the Issuers and the Guarantors that (i) any Exchange Securities to be received by
it will be acquired in the ordinary course of its business, (ii) at the time of the commencement of the Exchange Offer it has no arrangement or understanding with any Person to participate in
the distribution (within the meaning of the Securities Act) of the Exchange Securities in violation of the provisions of the Securities Act, (iii) it is not an "affiliate" (within the meaning
of Rule 405 under the Securities Act) of either of the Issuers or any Guarantor and (iv) if such Holder is a broker-dealer that will receive Exchange Securities for its own account in
exchange for Registrable Securities that were acquired as a result of market-making or other trading activities, then such Holder will deliver a Prospectus in connection with any resale of such
Exchange Securities. 

4

 

        As
soon as practicable after the last Exchange Date, the Issuers and the Guarantors shall: 

	(i)
	accept
for exchange Registrable Securities or portions thereof validly tendered and not properly withdrawn pursuant to the Exchange Offer; and

	(ii)
	deliver,
or cause to be delivered, to the Trustee for cancellation all Registrable Securities or portions thereof so accepted for exchange by the Issuers and issue, and cause the
Trustee to promptly authenticate and deliver to each Holder, Exchange Securities equal in principal amount to the principal amount of the Registrable Securities surrendered by such Holder. 

        The
Issuers and the Guarantors shall use their reasonable best efforts to complete the Exchange Offer as provided above and shall comply with the applicable requirements of the
Securities Act, the Exchange Act and other applicable laws and regulations in connection with the Exchange Offer. The Exchange Offer shall not be subject to any conditions, other than that the
Exchange Offer does not violate any applicable law or applicable interpretations of the Staff. 

        (b)   In
the event that (i) the Issuers and the Guarantors determine that the Exchange Offer Registration provided for in Section 2(a) above is not
available or may not be completed as soon as practicable after the last Exchange Date because it would violate any applicable law or applicable interpretations of the Staff, (ii) the Exchange
Offer is not for any other reason completed by April 25, 2005 or (iii) any Initial Purchaser shall so request in connection with any offer or sale of Registrable Securities that are not
eligible to be exchanged for Exchange Securities, the Issuers and the Guarantors shall use their reasonable best efforts to cause to be filed as soon as practicable after such determination, date or
request, as the case may be, a Shelf Registration Statement providing for the sale of all the Registrable Securities by the Holders thereof and to have such Shelf Registration Statement declared
effective by the SEC. 

        In
the event that the Issuers and the Guarantors are required to file a Shelf Registration Statement pursuant to clause (iii) of the preceding sentence, the Issuers
and the Guarantors shall use their reasonable best efforts to file and have declared effective by the SEC both an Exchange Offer Registration Statement pursuant to Section 2(a) with
respect to all Registrable Securities and a Shelf Registration Statement (which may be a combined Registration Statement with the Exchange Offer Registration Statement) with respect to offers and
sales of Registrable Securities held by the Initial Purchasers after completion of the Exchange Offer. 

        The
Issuers and the Guarantors agree to use their reasonable best efforts to keep the Shelf Registration Statement continuously effective until the expiration of the period referred to
in Rule 144(k) (or any similar rule then in force, but not Rule 144A) under the Securities Act with respect to the Registrable Securities or such shorter period that will
terminate when all the Registrable Securities covered by the Shelf Registration Statement have been sold pursuant to the Shelf Registration Statement (the "Shelf Effectiveness Period"). The Issuers
and the Guarantors further agree to supplement or amend the Shelf Registration Statement and the related Prospectus if required by the rules, regulations or instructions applicable to the registration
form used by the Issuers for such Shelf Registration Statement or by the Securities Act or by any other rules and regulations thereunder for shelf registration or if reasonably requested by a Holder
of Registrable Securities with respect to information relating to such Holder, and to use their reasonable best efforts to cause any such amendment to become effective and such Shelf Registration
Statement and Prospectus to become usable as soon as thereafter practicable. The Issuers and the Guarantors agree to furnish to the Holders of Registrable Securities copies of any such supplement or
amendment promptly after its being used or filed with the SEC. 

        (c)   The
Issuers and the Guarantors shall pay all Registration Expenses in connection with any registration pursuant to Section 2(a) or Section 2(b)
hereof. Each Holder shall pay all underwriting 

5

 

discounts
and commissions, brokerage commissions and transfer taxes, if any, relating to the sale or disposition of such Holder's Registrable Securities pursuant to the Shelf Registration Statement. 

        (d)   An
Exchange Offer Registration Statement pursuant to Section 2(a) hereof or a Shelf Registration Statement pursuant to Section 2(b) hereof
will not be deemed to have become effective unless it has been declared effective by the SEC. 

        In
the event that either the Exchange Offer is not completed or the Shelf Registration Statement, if required hereby, is not declared effective on or prior to April 25, 2005 (the
"Target Registration Date"), the interest rate on the Registrable Securities will be increased by (i) 0.50% per annum for the first 90-day period immediately following the Target
Registration Date and (ii) an additional 0.25% per annum with respect to each subsequent 90-day period, in each case until the Exchange Offer is completed or the Shelf Registration
Statement, if required hereby, is declared effective by the SEC or the Securities become freely tradable under the Securities Act, up to a maximum of 1.00% per annum of additional interest;  provided
that if an obligation to file a Shelf Registration Statement arises pursuant to Section 2(b)(iii) and the applicable
Initial Purchaser does not make the request to file a Shelf Registration Statement by February 25, 2005, then the Target Registration Date shall be extended by the number of days
from and including February 25, 2005 to and including the date on which such request is made. 

        If
the Shelf Registration Statement, if required hereby, has been declared effective and thereafter either ceases to be effective or the Prospectus contained therein ceases to be usable
at any time during the Shelf Effectiveness Period, and such failure to remain effective or usable exists for more than 60 days (whether or not consecutive) in any 12-month period,
then the interest rate on the Registrable Securities will be increased by (i) 0.50% per annum commencing on the 61st day in such 12-month period and (ii) an additional 0.25%
per annum with respect to each subsequent 90-day period (whether or not consecutive) and ending on such date that the Shelf Registration Statement has again been declared effective or the
Prospectus again becomes usable, up to a maximum of 1.00% per annum of additional interest. 

        (e)   Without
limiting the remedies available to the Initial Purchasers and the Holders, the Issuers and the Guarantors acknowledge that any failure by the Issuers or the
Guarantors to comply with their obligations under Section 2(a) and Section 2(b) hereof may result in material irreparable injury to the Initial Purchasers or the Holders for which
there is no adequate remedy at law, that it will not be possible to measure damages for such injuries precisely and that, in the event of any such failure, the Initial Purchasers or any Holder may
obtain such relief as may be required to specifically enforce the Issuers' and the Guarantors' obligations under Section 2(a) and Section 2(b) hereof. 

        3.    Registration Procedures.    (a) In connection with their obligations pursuant to
Section 2(a) and Section 2(b) hereof, the Issuers and the Guarantors shall as expeditiously as possible: 

        (i)    prepare
and file with the SEC a Registration Statement on the appropriate form under the Securities Act, which form (x) shall be selected by the Issuers
and the Guarantors, (y) shall, in the case of a Shelf Registration, be available for the sale of the Registrable Securities by the Holders thereof and (z) shall comply as to form in all
material respects with the requirements of the applicable form and include all financial statements required by the SEC to be filed therewith; and use their reasonable best efforts to
cause such Registration Statement to become effective and remain effective for the applicable period in accordance with Section 2 hereof; 

        (ii)   prepare
and file with the SEC such amendments and post-effective amendments to each Registration Statement as may be necessary to keep such Registration
Statement effective for the applicable period in accordance with Section 2 hereof and cause each Prospectus to be supplemented by any required prospectus supplement and, as so supplemented, to
be filed pursuant to Rule 424 under the Securities Act; and keep each Prospectus current during the period 

6

 

described
in Section 4(3) of and Rule 174 under the Securities Act that is applicable to transactions by brokers or dealers with respect to the Registrable Securities or Exchange
Securities; 

        (iii)  in
the case of a Shelf Registration, furnish to each Holder of Registrable Securities, to counsel for the Initial Purchasers, to counsel for such Holders and to each
Underwriter of an Underwritten Offering of Registrable Securities, if any, without charge, as many copies of each Prospectus, including each preliminary Prospectus, and any amendment or supplement
thereto, in order to facilitate the sale or other disposition of the Registrable Securities thereunder; and the Issuers and the Guarantors consent to the use of such Prospectus and any amendment or
supplement thereto in accordance with applicable law by each of the Holders of Registrable Securities and any such Underwriters in connection with the offering and sale of the Registrable Securities
covered by and in the manner described in such Prospectus or any amendment or supplement thereto in accordance with applicable law; 

        (iv)  use
their reasonable best efforts to register or qualify the Registrable Securities under all applicable state securities or blue sky laws of such jurisdictions in the
United States as any Holder of Registrable Securities covered by a Registration Statement shall reasonably request in writing by the time the applicable Registration Statement is declared effective by
the SEC; cooperate with such Holders in connection with any filings required to be made with the National Association of Securities Dealers, Inc.; and do any and all other acts and things that
may be reasonably necessary or advisable to enable each Holder to complete the disposition in each such jurisdiction of the Registrable Securities owned by such Holder;  provided that none of the Issuers
or the Guarantors shall be required to (1) qualify as a foreign corporation or other entity or as a dealer in
securities in any such jurisdiction where it would not otherwise be required to so qualify, (2) file any general consent to service of process in any such jurisdiction or (3) subject
itself to taxation in any such jurisdiction if it is not so subject; 

        (v)   in
the case of a Shelf Registration, notify each Holder of Registrable Securities, counsel for such Holders and counsel for the Initial Purchasers promptly and, if
requested by any such Holder or counsel, confirm such advice in writing (1) when a Registration Statement has become effective and when any post-effective amendment thereto has been
filed and becomes effective, (2) of any request by the SEC or any state securities authority for amendments and supplements to a Registration Statement and Prospectus or for additional
information after the Registration Statement has become effective, (3) of the issuance by the SEC or any state securities authority of any stop order
suspending the effectiveness of a Registration Statement or the initiation of any proceedings for that purpose, (4) if, between the effective date of a Registration Statement and the closing of
any sale of Registrable Securities covered thereby, the representations and warranties of either of the Issuers or any Guarantor contained in any underwriting agreement, securities sales agreement or
other similar agreement, if any, relating to an offering of such Registrable Securities cease to be true and correct in all material respects or if either of the Issuers or any Guarantor receives any
notification with respect to the suspension of the qualification of the Registrable Securities for sale in any jurisdiction or the initiation of any proceeding for such purpose, (5) of the
happening of any event during the period a Shelf Registration Statement is effective that makes any statement made in such Registration Statement or the related Prospectus untrue in any material
respect or that requires the making of any changes in such Registration Statement or Prospectus in order to make the statements therein not misleading and (6) of any determination by either of
the Issuers or any Guarantor that a post-effective amendment to a Registration Statement would be appropriate; 

        (vi)  use
their reasonable best efforts to obtain the withdrawal of any order suspending the effectiveness of a Registration Statement at the earliest possible moment and
provide immediate notice to each Holder of the withdrawal of any such order; 

7

  

        (vii) in
the case of a Shelf Registration, furnish to each Holder of Registrable Securities, without charge, at least one conformed copy of each Registration Statement and
any post-effective amendment thereto (without any documents incorporated therein by reference or exhibits thereto, unless requested); 

        (viii)   in
the case of a Shelf Registration, cooperate with the Holders of any Registrable Securities in certificated form to facilitate the timely preparation
and delivery of certificates representing Registrable Securities to be sold and not bearing any restrictive legends and enable such Registrable Securities to be issued in such denominations and
registered in such names (consistent with the provisions of the Indenture) as such Holders may reasonably request at least one Business Day prior to the closing of any sale of Registrable Securities
in certificated form; 

        (ix)  in
the case of a Shelf Registration, upon the occurrence of any event contemplated by Section 3(a)(v)(5) hereof, use their reasonable best efforts to prepare and
file with the SEC a supplement or post-effective amendment to such Shelf Registration Statement or the related Prospectus or any document incorporated therein by reference or file any
other required document so that, as thereafter delivered to purchasers of the Registrable Securities, such Prospectus will not contain any untrue statement of a material fact or omit to state a
material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and the Issuers and the Guarantors shall notify the Holders of
Registrable Securities to suspend use of the Prospectus as promptly as practicable after the occurrence of such an event, and such Holders hereby agree to suspend use of the Prospectus until the
Issuers and the Guarantors have amended or supplemented the Prospectus to correct such misstatement or omission; 

        (x)   a
reasonable time prior to the filing of any Registration Statement, any Prospectus, any amendment to a Registration Statement or amendment or supplement to a Prospectus
or of any document that is to be incorporated by reference into a Registration Statement or a Prospectus after initial filing of a Registration Statement, provide copies of such document to the
Initial Purchasers and their counsel (and, in the case of a Shelf Registration Statement, to the Holders of Registrable Securities and their counsel) and make such of the representatives of the
Issuers and the Guarantors as shall be reasonably requested by the Initial Purchasers or their counsel (and, in the case of a Shelf Registration Statement, the Holders of Registrable Securities or
their counsel) available for discussion of such document; and the Issuers and the Guarantors shall not, at any time after initial filing of a Registration Statement, file any Prospectus, any amendment
of or supplement to a Registration Statement or a Prospectus, or any document that is to be incorporated by reference into a Registration Statement or a Prospectus, of which the Initial Purchasers and
their counsel (and, in the case of a Shelf Registration Statement, the Holders of Registrable Securities and their counsel) shall not have previously been advised and furnished a copy or to which the
Initial Purchasers or their counsel (and, in the case of a Shelf Registration Statement, the Holders of Registrable Securities or their counsel) shall object;  provided, that this clause shall not apply
to any filing by the Partnership of any Annual Report on
Form 10-K, Quarterly Report on Form 10-Q or Current Report on Form 8-K with respect to matters unrelated to the Securities and the offering or
exchange therefor; 

        (xi)  obtain
a CUSIP number for all Exchange Securities or Registrable Securities, as the case may be, not later than the effective date of a Registration Statement; 

        (xii) cause
the Indenture to be qualified under the Trust Indenture Act in connection with the registration of the Exchange Securities or Registrable Securities, as the case
may be; cooperate with the Trustee and the Holders to effect such changes to the Indenture as may be required for the Indenture to be so qualified in accordance with the terms of the Trust Indenture
Act; and execute, and use their reasonable best efforts to cause the Trustee to execute, all documents as 

8

 

may
be required to effect such changes and all other forms and documents required to be filed with the SEC to enable the Indenture to be so qualified in a timely manner; 

        (xiii)   in
the case of a Shelf Registration, make available for inspection by a representative of the Holders of the Registrable Securities (an "Inspector"),
any Underwriter participating in any disposition pursuant to such Shelf Registration Statement, any attorneys and accountants designated by the Holders of Registrable Securities and any attorneys and
accountants designated by such Underwriter, at reasonable times and in a reasonable manner, all pertinent financial and other records, documents and properties of the Issuers and the Guarantors, and
cause the respective officers, directors and employees of the Issuers and the Guarantors to supply all information reasonably requested by any such Inspector, Underwriter, attorney or accountant in
connection with a Shelf Registration Statement; provided that if any such information is identified by either of the Issuers or any Guarantor as being
confidential or proprietary, each Person receiving such information shall take such actions as are reasonably necessary to protect the confidentiality of such information to the extent such action is
otherwise not inconsistent with, an impairment of or in derogation of the rights and interests of any Inspector, Holder or Underwriter); 

        (xiv)   in
the case of a Shelf Registration, use their reasonable best efforts to cause all Registrable Securities to be listed on any securities exchange or any
automated quotation system on which similar securities issued or guaranteed by either of the Issuers or any Guarantor are then listed if requested by the Majority Holders, to the extent such
Registrable Securities satisfy applicable listing requirements; 

        (xv) if
reasonably requested by any Holder of Registrable Securities covered by a Shelf Registration Statement, promptly include in a Prospectus supplement or
post-effective amendment such information with respect to such Holder as such Holder reasonably requests to be included therein and make all required filings of such Prospectus supplement
or such
post-effective amendment as soon as the Issuers have received notification of the matters to be so included in such filing; and 

        (xvi)   in
the case of a Shelf Registration, enter into such customary agreements and take all such other actions in connection therewith (including those
requested by the Holders of a majority in principal amount of the Registrable Securities being sold) in order to expedite or facilitate the disposition of such Registrable Securities including, but
not limited to, an Underwritten Offering and in such connection, (1) to the extent possible, make such representations and warranties to the Holders and any Underwriters of such Registrable
Securities with respect to the business of the Issuers and their subsidiaries and the Registration Statement, Prospectus and documents incorporated by reference or deemed incorporated by reference, if
any, in each case, in form, substance and scope as are customarily made by issuers to underwriters in underwritten offerings and confirm the same if and when requested, (2) obtain opinions of
counsel to the Issuers and the Guarantors (which counsel and opinions, in form, scope and substance, shall be reasonably satisfactory to the Holders and such Underwriters and their respective counsel)
addressed to each selling Holder and Underwriter of Registrable Securities, covering the matters customarily covered in opinions requested in underwritten offerings, (3) obtain "comfort"
letters from the independent certified public accountants of the Issuers and the Guarantors (and, if necessary, any other certified public accountant of any subsidiary of either of the Issuers or any
Guarantor, or of any business acquired by either of the Issuers or any Guarantor for which financial statements and financial data are or are required to be included in the Registration Statement)
addressed to each selling Holder and Underwriter of Registrable Securities, such letters to be in customary form and covering matters of the type customarily covered in "comfort" letters in connection
with underwritten offerings and (4) deliver such documents and certificates as may be reasonably requested by the Holders of a majority in principal amount of the Registrable Securities being
sold 

9

 

or
the Underwriters, and which are customarily delivered in underwritten offerings, to evidence the continued validity of the representations and warranties of the Issuers and the Guarantors made
pursuant to clause (1) above and to evidence compliance with any customary conditions contained in an underwriting agreement. 

        (b)   In
the case of a Shelf Registration Statement, the Issuers may require each Holder of Registrable Securities to furnish to the Issuers such information regarding such
Holder and the proposed disposition by such Holder of such Registrable Securities as the Issuers and the Guarantors may from time to time reasonably request in writing. 

        (c)   In
the case of a Shelf Registration Statement, each Holder of Registrable Securities agrees that, upon receipt of any notice from the Issuers and the Guarantors of the
happening of any event of the kind described in Section 3(a)(v)(3) or 3(a)(v)(5) hereof, such Holder will forthwith discontinue disposition of Registrable Securities pursuant to the
Shelf Registration Statement until such Holder's receipt of the copies of the supplemented or amended Prospectus contemplated by Section 3(a)(ix) hereof and, if so directed by the
Issuers and the Guarantors, such Holder will deliver to the Issuers and the Guarantors all copies in its possession, other than permanent file copies then in such Holder's possession, of the
Prospectus covering such Registrable Securities that is current at the time of receipt of such notice. 

        (d)   If
the Issuers and the Guarantors shall give any notice pursuant to Section 3(c) hereof to suspend the disposition of Registrable Securities pursuant to a Shelf
Registration Statement, the Issuers and the Guarantors shall extend the period during which such Shelf Registration Statement shall be maintained effective pursuant to this Agreement by the number
of days during the period from and including the date of the giving of such notice to and including the date when the Holders of such Registrable Securities shall have received copies of the
supplemented or amended Prospectus necessary to resume such dispositions. Any such suspensions shall not, in the aggregate, exceed 90 days during any 365-day period. 

        (e)   The
Holders of Registrable Securities covered by a Shelf Registration Statement who desire to do so may sell such Registrable Securities in an Underwritten Offering. In
any such Underwritten Offering, the investment bank or investment banks and manager or managers (each an "Underwriter") that will administer the offering will be selected by the Holders of a majority
in principal amount of the Registrable Securities included in such offering. 

        4.    Participation of Broker-Dealers in Exchange Offer.    (a) The Staff has taken the position that any
broker-dealer that receives Exchange Securities for its own account in the Exchange Offer in exchange for Securities that were acquired by such broker-dealer as a result of market-making or other
trading activities (a "Participating Broker-Dealer") may be deemed to be an "underwriter" within the meaning of the Securities Act and must deliver a prospectus meeting the requirements of the
Securities Act in connection with any resale of such Exchange Securities. 

        The
Issuers and the Guarantors understand that it is the Staff's position that if the Prospectus contained in the Exchange Offer Registration Statement includes a plan of distribution
containing a statement to the above effect and the means by which Participating Broker-Dealers may resell the Exchange Securities, without naming the Participating Broker-Dealers or specifying the
amount of Exchange Securities owned by them, such Prospectus may be delivered by Participating Broker-Dealers to satisfy their prospectus delivery obligation under the Securities Act in connection
with resales of Exchange Securities for their own accounts, so long as the Prospectus otherwise meets the requirements of the Securities Act. 

        (b)   In
light of the above, and notwithstanding the other provisions of this Agreement, the Issuers and the Guarantors agree to amend or supplement the Prospectus contained
in the Exchange Offer Registration Statement for a period of up to 180 days after the last Exchange Date (as such period may 

10

 

be
extended pursuant to Section 3(d) of this Agreement), if requested by the Initial Purchasers or by one or more Participating Broker-Dealers, in order to expedite or facilitate the
disposition of any Exchange Securities by Participating Broker-Dealers consistent with the positions of the Staff recited in Section 4(a) above. The Issuers and the Guarantors further agree
that Participating Broker-Dealers shall be authorized to deliver such Prospectus during such period in connection with the resales contemplated by this Section 4. 

        (c)   The
Initial Purchasers shall have no liability to either of the Issuers, any Guarantor or any Holder with respect to any request that they may make pursuant to
Section 4(b) above. 

        5.    Indemnification and Contribution.    (a) Each Issuer and each Guarantor, jointly and severally, agree to
indemnify and hold harmless each Initial Purchaser and each Holder, their respective affiliates, directors and officers and each Person, if any, who controls any Initial Purchaser or any Holder within
the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, from and against any and all losses, claims, damages and liabilities (including, without limitation,
legal fees and other expenses incurred in connection with any suit, action or proceeding or any claim asserted, as such fees and expenses are incurred), that arise out of, or are based upon, any
untrue statement or alleged untrue statement of a material fact contained in any Registration Statement or any Prospectus or any omission or alleged omission to state therein a material fact required
to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, except insofar as such losses, claims, damages
or liabilities arise out of, or are based upon, any untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any
Initial Purchaser or information relating to any Holder furnished to the Issuers in writing through JPMorgan or any selling Holder expressly for use therein. In connection with any Underwritten
Offering permitted by Section 3, the Issuers and the Guarantors, jointly and severally, will also indemnify the Underwriters, if any, selling brokers, dealers and similar securities industry
professionals participating in the distribution, their respective affiliates and each Person who controls such Persons (within the meaning of the Securities Act and the Exchange Act) to the same
extent as provided above with respect to the indemnification of the Holders, if requested in connection with any Registration Statement. 

        (b)   Each
Holder agrees, severally and not jointly, to indemnify and hold harmless the Issuers, the Guarantors, the Initial Purchasers and the other selling Holders, the
directors of the Issuers and the Guarantors, each officer of the Issuers and the Guarantors who signed the Registration Statement and each Person, if any, who controls the Issuers, the Guarantors, any
Initial Purchaser and any other selling Holder within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the indemnity set forth in
paragraph (a) above, but only with respect to any losses, claims, damages or liabilities that arise out of, or are based upon, any untrue statement or omission or alleged untrue
statement or omission made in reliance upon and in conformity with any information relating to such Holder furnished to the Issuers in writing by such Holder expressly for use in any Registration
Statement and any Prospectus. 

        (c)   If
any suit, action, proceeding (including any governmental or regulatory investigation), claim or demand shall be brought or asserted against any Person in respect of
which indemnification may be sought pursuant to either paragraph (a) or (b) above, such Person (the "Indemnified Person") shall promptly notify the Person against whom such
indemnification may be sought (the "Indemnifying Person") in writing; provided that the failure to notify the Indemnifying Person shall not relieve it
from any liability that it may have under this Section 5 except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure;
and provided, further, that the failure to notify the Indemnifying Person shall not relieve it from any
liability that it may have to an Indemnified Person otherwise than under this Section 5. If any such proceeding shall be brought or asserted against an Indemnified Person and it shall have
notified the Indemnifying Person thereof, the Indemnifying Person shall retain counsel reasonably satisfactory to the Indemnified 

11

 

Person
to represent the Indemnified Person and any others entitled to indemnification pursuant to this Section 5 that the Indemnifying Person may designate in such proceeding and shall pay the
fees and expenses of such counsel related to such proceeding, as incurred. In any such proceeding, any Indemnified Person shall have the right to retain its own counsel, but the fees and expenses of
such counsel shall be at the expense of such Indemnified Person unless (i) the Indemnifying Person and the Indemnified Person shall have mutually agreed to the contrary; (ii) the
Indemnifying Person has failed within a reasonable time to retain counsel reasonably satisfactory to the Indemnified Person; (iii) the Indemnified Person shall have reasonably concluded that
there may be legal defenses available to it that are different from or in addition to those available to the Indemnifying Person; or (iv) the named parties in any such proceeding (including any
impleaded parties) include both the Indemnifying Person and the Indemnified Person and representation of both parties by the same counsel would be inappropriate due to actual or potential differing
interests between them. It is understood and agreed that the Indemnifying Person shall not, in connection with any proceeding or related proceeding in the same jurisdiction, be liable for the fees and
expenses of more than one separate firm (in addition to any local counsel) for all Indemnified Persons, and that all such fees and expenses shall be reimbursed as they are incurred. Any such separate
firm (x) for any Initial Purchaser, its affiliates, directors and officers and any control Persons of such Initial Purchaser shall be designated in writing by JPMorgan, (y) for any
Holder, its directors and officers and any control Persons of such Holder shall be designated in writing by the Majority Holders and (z) in all other cases shall be designated in writing by the
Issuers. The Indemnifying Person shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the
plaintiff, the Indemnifying Person agrees to indemnify each Indemnified Person from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence,
if at any time an Indemnified Person shall have requested that an Indemnifying Person reimburse the Indemnified Person for fees and expenses of counsel as contemplated by this paragraph, the
Indemnifying Person shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by
the Indemnifying Person of such request and (ii) the Indemnifying Person shall not have reimbursed the Indemnified Person in accordance with such request prior to the date of such settlement.
No Indemnifying Person shall, without the written consent of the Indemnified Person, effect any settlement of any pending or threatened proceeding in respect of which any Indemnified Person is or
could have been a party and indemnification could have been sought hereunder by such Indemnified Person, unless such settlement (A) includes an unconditional release of such Indemnified Person,
in form and substance reasonably satisfactory to such Indemnified Person, from all liability on claims that are the subject matter of such proceeding and (B) does not include any statement as
to or any admission of fault, culpability or a failure to act by or on behalf of any Indemnified Person. 

        (d)   If
the indemnification provided for in paragraphs (a) and (b) above is unavailable to an Indemnified Person or insufficient in respect of any losses,
claims, damages or liabilities referred to therein, then each Indemnifying Person under such paragraph, in lieu of indemnifying such Indemnified Person thereunder, shall contribute to the amount paid
or payable by such Indemnified Person as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the
Issuers and the Guarantors from the offering of the Securities and the Exchange Securities, on the one hand, and by the Holders from receiving Securities or Exchange Securities registered under the
Securities Act, on the other hand, or (ii) if the allocation provided by clause (i) is not permitted by applicable law, in such proportion as is appropriate to reflect not only
the relative benefits referred to in clause (i) but also the relative fault of the Issuers and the Guarantors on the one hand and the Holders on the other in connection with the
statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative fault of the Issuers and the Guarantors on
the one hand and the Holders on the other shall be determined by reference to, among other things, whether the untrue or alleged 

12

 

untrue
statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Issuers and the Guarantors or by the Holders, and the parties'
relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. 

        (e)   The
Issuers, the Guarantors and the Holders agree that it would not be just and equitable if contribution pursuant to this Section 5 were determined by  pro rata allocation (even if the Holders were
treated as one entity for such purpose) or by any other method of allocation that does not take account of
the equitable considerations referred to in paragraph (d) above. The amount paid or payable by an Indemnified Person as a result of the losses, claims, damages and liabilities referred
to in paragraph (d) above shall be deemed to include, subject to the limitations set forth above, any legal or other expenses incurred by such Indemnified Person in connection with any
such action or claim. Notwithstanding the provisions of this Section 5, in no event shall a Holder be required to contribute any amount in excess of the amount by which the total price at which
the Securities or Exchange Securities sold by such Holder exceeds the amount of any damages that such Holder has otherwise been required to pay by reason of such untrue or alleged untrue statement or
omission or alleged omission. No Person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any
Person who was not guilty of such fraudulent misrepresentation. 

        (f)    The
remedies provided for in this Section 5 are not exclusive and shall not limit any rights or remedies that may otherwise be available to any Indemnified Person
at law or in equity. 

        (g)   The
indemnity and contribution provisions contained in this Section 5 shall remain operative and in full force and effect regardless of (i) any termination
of this Agreement, (ii) any investigation made by or on behalf of the Initial Purchasers or any Holder or any Person controlling any Initial Purchaser or any Holder, or by or on behalf of the
Issuers or the Guarantors or the officers or directors of or any Person controlling the Issuers or the Guarantors, (iii) acceptance of any of the Exchange Securities and (iv) any sale of
Registrable Securities pursuant to a Shelf Registration Statement. 

        6.    General.    

        (a)    No Inconsistent Agreements.    The Issuers and the Guarantors represent, warrant and agree that (i) the
rights granted to the Holders hereunder do not in any way conflict with and are not inconsistent with the rights granted to the holders of any other outstanding securities issued or guaranteed by
either of the Issuers or any Guarantor under any other agreement and (ii) neither the Issuers nor any Guarantor has entered into, or on or after the date of this Agreement will enter into, any
agreement that is inconsistent with the rights granted to the Holders of Registrable Securities in this Agreement or otherwise conflicts with the provisions hereof. 

        (b)    Amendments and Waivers.    The provisions of this Agreement, including the provisions of this sentence, may not
be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given unless the Issuers and the Guarantors have obtained the written consent of
Holders of at least a majority in aggregate principal amount of the outstanding Registrable Securities affected by such amendment, modification, supplement, waiver or consent;  provided that no amendment,
 modification, supplement, waiver or consent to any departure from the provisions of Section 5 hereof shall be
effective as against any Holder of Registrable Securities unless consented to in writing by such Holder. Any amendments, modifications, supplements, waivers or consents pursuant to this
Section 6(b) shall be by a writing executed by each of the parties hereto. 

        (c)    Notices.    All notices and other communications provided for or permitted hereunder shall be made in writing
by hand-delivery, registered first-class mail, telecopier, or any courier guaranteeing overnight delivery (i) if to a Holder, at the most current address given by such Holder to the
Issuers by 

13

 

means
of a notice given in accordance with the provisions of this Section 6(c), which address initially is, with respect to the Initial Purchasers, the address set forth in the Purchase
Agreement; (ii) if to the Issuers and the Guarantors, initially at the Issuers' address set forth in the Purchase Agreement and thereafter at such other address, notice of which is given in
accordance with the provisions of this Section 6(c); and (iii) to such other persons at their respective addresses as provided in the Purchase Agreement and thereafter at such other
address, notice of which is given in accordance with the provisions of this Section 6(c). All such notices and communications shall be deemed to have been duly given: at the time delivered by
hand, if personally delivered; five Business Days after being deposited in the mail, postage prepaid, if mailed; when receipt is acknowledged, if telecopied; and on the next Business Day if timely
delivered to an air courier guaranteeing overnight delivery. Copies of all such notices, demands or other communications shall be concurrently delivered by the Person giving the same to the Trustee,
at the address specified in the Indenture. 

        (d)    Successors and Assigns.    This Agreement shall inure to the benefit of and be binding upon the successors,
assigns and transferees of each of the parties, including, without limitation and without the need for an express assignment, subsequent Holders;  provided that nothing herein shall be deemed to permit
any assignment, transfer or other disposition of Registrable Securities in violation of the terms
of the Purchase Agreement or the Indenture. If any transferee of any Holder shall acquire Registrable Securities in any manner, whether by operation of law or otherwise, such Registrable Securities
shall be held subject to all the terms of this Agreement, and by taking and holding such Registrable Securities such Person shall be conclusively deemed to have agreed to be bound by and to perform
all of the terms and provisions of this Agreement and such Person shall be entitled to receive the benefits hereof. The Initial Purchasers (in their capacity as Initial Purchasers) shall have no
liability or obligation to the Issuers or the Guarantors with respect to any failure by a Holder to comply with, or any breach by any Holder of, any of the obligations of such Holder under this
Agreement. 

        (e)    Third Party Beneficiaries.    Each Holder shall be a third party beneficiary to the agreements made between the
Issuers and the Guarantors, on the one hand, and the Initial Purchasers, on the other hand, and shall have the right to enforce such agreements directly to the extent it deems such enforcement
necessary or advisable to protect its rights or the rights of other Holders hereunder. 

        (f)    Counterparts.    This Agreement may be executed in any number of counterparts and by the parties hereto in
separate counterparts, each of which when so executed shall be deemed to be an original and all of which taken together shall constitute one and the same agreement. 

        (g)    Headings.    The headings in this Agreement are for convenience of reference only, are not a part of this
Agreement and shall not limit or otherwise affect the meaning hereof. 

        (h)    Governing Law.    This Agreement shall be governed by and construed in accordance with the laws of the State of
New York. 

        (j)    Miscellaneous.    This Agreement contains the entire agreement between the parties relating to the subject
matter hereof and supersedes all oral statements and prior writings with respect thereto. If any term, provision, covenant or restriction contained in this Agreement is held by a court of competent
jurisdiction to be invalid, void or unenforceable or against public policy, the remainder of the terms, provisions, covenants and restrictions contained herein shall remain in full force and effect
and shall in no way be affected, impaired or invalidated. The Issuers, the Guarantors and the Initial Purchasers shall endeavor in good faith negotiations to replace the invalid, void or unenforceable
provisions with valid provisions the economic effect of which comes as close as possible to that of the invalid, void or unenforceable provisions. 

14

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

Issuers:

	MARKWEST ENERGY PARTNERS, L.P.	 
	
 By:	
 	

MARKWEST ENERGY GP, L.L.C., its general partner	

 
	

 	
 	

By:	

/s/  ANDREW L. SCHROEDER      
	

 
	 	 	Name: Andrew L. Schroeder	 
	 	 	Title: Vice President	 
	
MARKWEST ENERGY FINANCE CORPORATION	

 
	

 	
 	

BY:	

/S/  ANDREW L. SCHROEDER      
	

 
	 	 	Name: Andrew L. Schroeder	 
	 	 	Title: Vice President	 

15

 

	 	 	Guarantors:
	

 	
 	

MARKWEST ENERGY OPERATING COMPANY, L.L.C.

BASIN PIPELINE L.L.C.

WEST SHORE PROCESSING COMPANY, L.L.C.

MARKWEST ENERGY APPALACHIA, L.L.C.

MARKWEST TEXAS GP, L.L.C.

MW TEXAS LIMITED, L.L.C.

MARKWEST MICHIGAN PIPELINE COMPANY, L.L.C.

MARKWEST WESTERN OKLAHOMA GAS COMPANY, L.L.C.
	

 	
 	

By:	

/s/  ANDREW L. SCHROEDER      

	 	 	Name: Andrew L. Schroeder
	 	 	Title: Vice President

	

 	
 	

MARKWEST POWER TEX L.P.

MARKWEST PINNACLE L.P.

MARKWEST PNG UTILITY L.P.

MARKWEST TEXAS PNG UTILITY L.P.

MARKWEST BLACKHAWK L.P.

MARKWEST NEW MEXICO L.P.

MARKWEST ENERGY EAST TEXAS GAS COMPANY L.P.
	

 	
 	

By:	
 	

MARKWEST TEXAS GP, L.L.C., its general partner
	

 	
 	

 	
 	

By:	

/s/  ANDREW L. SCHROEDER      

	 	 	 	 	Name: Andrew L. Schroeder
	 	 	 	 	Title: Vice President

16

 

Confirmed
and accepted as of the date first above written: 

J.P.
MORGAN SECURITIES INC. 

For
itself and on behalf of the

several Initial Purchasers 

	

By	

/s/  DANIEL POMBO      
	

 
	Name: Daniel Pombo	 
	Title: Vice President	 

17

   Schedule 1  

Guarantors  

MarkWest
Energy Operating Company, L.L.C. 

Basin
Pipeline L.L.C. 

West
Shore Processing Company, L.L.C. 

MarkWest
Energy Appalachia, L.L.C. 

MarkWest
Texas GP, L.L.C. 

MW
Texas Limited, L.L.C. 

MarkWest
Michigan Pipeline Company, L.L.C. 

MarkWest
Western Oklahoma Gas Company, L.L.C. 

MarkWest
Power Tex, L.P. 

MarkWest
Pinnacle L.P. 

MarkWest
PNG Utility L.P. 

MarkWest
Texas PNG Utility L.P. 

MarkWest
Blackhawk L.P. 

MarkWest
New Mexico L.P. 

MarkWest
Energy East Texas Gas Company L.P. 

18

QuickLinks

REGISTRATION RIGHTS AGREEMENT

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