Document:

Exhibit 10.1

 

Date

 

Georgia Gulf Corporation

115 Perimeter Center Place

Atlanta, GA 30346

 

Re:  Forfeiture of Stock Options

 

Dear
                        ,

 

This letter is to advise you
that I voluntarily forfeit
             stock
options granted to me on February 28, 2005 with a grant price of $53.38.
The purpose is to return these to the Company so that the Company may make
further grants to other employees. I acknowledge that the Company has made no
commitment to grant any new equity awards to replace the forfeited options and
I understand that the options I have forfeited will not be used to make a
future equity grant to me.

 

Sincerely,

 

 

OfficerExhibit 4.1

 

Execution Version

 

 

 

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 May 26, 2009

 

 

 

 

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

  	
  5

  
	
  Section 1.01.

  	
  Definitions

  	
  5

  
	
  Section 1.02.

  	
  Other Definitions

  	
  32

  
	
  Section 1.03.

  	
  Incorporation by Reference
  of Trust Indenture Act

  	
  32

  
	
  Section 1.04.

  	
  Rules of Construction

  	
  33

  
	
   

  	
   

  	
   

  
	
  ARTICLE 2 THE NOTES

  	
  33

  
	
  Section 2.01.

  	
  Form and Dating

  	
  33

  
	
  Section 2.02.

  	
  Execution and
  Authentication

  	
  34

  
	
  Section 2.03.

  	
  Registrar and Paying Agent

  	
  35

  
	
  Section 2.04.

  	
  Paying Agent to Hold Money
  in Trust

  	
  35

  
	
  Section 2.05.

  	
  Holder Lists

  	
  36

  
	
  Section 2.06.

  	
  Transfer and Exchange

  	
  36

  
	
  Section 2.07.

  	
  Replacement Notes

  	
  46

  
	
  Section 2.08.

  	
  Outstanding Notes

  	
  46

  
	
  Section 2.09.

  	
  Treasury Notes

  	
  47

  
	
  Section 2.10.

  	
  Temporary Notes

  	
  47

  
	
  Section 2.11.

  	
  Cancellation

  	
  47

  
	
  Section 2.12.

  	
  Defaulted Interest

  	
  47

  
	
  Section 2.13.

  	
  CUSIP Numbers

  	
  48

  
	
   

  	
   

  	
   

  
	
  ARTICLE 3 REDEMPTION AND PREPAYMENT

  	
  48

  
	
  Section 3.01.

  	
  Notices to Trustee

  	
  48

  
	
  Section 3.02.

  	
  Selection of Notes to Be
  Redeemed

  	
  48

  
	
  Section 3.03.

  	
  Notice of Redemption

  	
  49

  
	
  Section 3.04.

  	
  Effect of Notice of
  Redemption

  	
  50

  
	
  Section 3.05.

  	
  Deposit of Redemption
  Price

  	
  50

  
	
  Section 3.06.

  	
  Notes Redeemed in Part

  	
  50

  
	
  Section 3.07.

  	
  Optional Redemption

  	
  51

  
	
  Section 3.08.

  	
  Mandatory Redemption

  	
  51

  
	
  Section 3.09.

  	
  Offer to Purchase by
  Application of Net Proceeds

  	
  51

  
	
   

  	
   

  	
   

  
	
  ARTICLE 4 COVENANTS

  	
  53

  
	
  Section 4.01.

  	
  Payment of Notes

  	
  53

  
	
  Section 4.02.

  	
  Maintenance of Office or
  Agency

  	
  54

  
	
  Section 4.03.

  	
  Compliance Certificate

  	
  54

  
	
  Section 4.04.

  	
  Taxes

  	
  55

  
	
  Section 4.05.

  	
  Stay, Extension and Usury
  Laws

  	
  55

  
	
  Section 4.06.

  	
  Change of Control

  	
  55

  
	
  Section 4.07.

  	
  Asset Sales

  	
  58

  
	
  Section 4.08.

  	
  Restricted Payments

  	
  60

  
	
  Section 4.09.

  	
  Incurrence of Indebtedness
  and Issuance of Disqualified Equity

  	
  63

  
	
  Section 4.10.

  	
  Liens

  	
  66

  
	
  Section 4.11.

  	
  Dividend and Other Payment
  Restrictions Affecting Subsidiaries

  	
  66

  

 

i

 

TABLE OF
CONTENTS

 

	
   

  	
   

  	
  Page

  
	
   

  	
   

  	
   

  
	
  Section 4.12.

  	
  Transactions With
  Affiliates

  	
  68

  
	
  Section 4.13.

  	
  Additional Subsidiary
  Guarantees

  	
  69

  
	
  Section 4.14.

  	
  Designation of Restricted
  and Unrestricted Subsidiaries

  	
  70

  
	
  Section 4.15.

  	
  Business Activities

  	
  70

  
	
  Section 4.16.

  	
  Sale and Leaseback
  Transactions

  	
  70

  
	
  Section 4.17.

  	
  Payments for Consent

  	
  71

  
	
  Section 4.18.

  	
  Reports

  	
  71

  
	
  Section 4.19.

  	
  Suspension of Covenants

  	
  72

  
	
  Section 4.20.

  	
  Calculation of Original
  Issue Discount

  	
  73

  
	
   

  	
   

  	
   

  
	
  ARTICLE 5 SUCCESSORS

  	
  73

  
	
  Section 5.01.

  	
  Merger, Consolidation, or
  Sale of Assets

  	
  73

  
	
  Section 5.02.

  	
  Successor Entity
  Substituted

  	
  75

  
	
   

  	
   

  	
   

  
	
  ARTICLE 6 DEFAULTS AND REMEDIES

  	
  76

  
	
  Section 6.01.

  	
  Events of Default

  	
  76

  
	
  Section 6.02.

  	
  Acceleration

  	
  78

  
	
  Section 6.03.

  	
  Other Remedies

  	
  78

  
	
  Section 6.04.

  	
  Waiver of Past Defaults

  	
  79

  
	
  Section 6.05.

  	
  Control by Majority

  	
  79

  
	
  Section 6.06.

  	
  Limitation on Suits

  	
  79

  
	
  Section 6.07.

  	
  Rights of Holders of Notes
  to Receive Payment

  	
  80

  
	
  Section 6.08.

  	
  Collection Suit by Trustee

  	
  80

  
	
  Section 6.09.

  	
  Trustee May File
  Proofs of Claim

  	
  80

  
	
  Section 6.10.

  	
  Priorities

  	
  81

  
	
  Section 6.11.

  	
  Undertaking for Costs

  	
  81

  
	
   

  	
   

  	
   

  
	
  ARTICLE 7 TRUSTEE

  	
  81

  
	
  Section 7.01.

  	
  Duties of Trustee

  	
  81

  
	
  Section 7.02.

  	
  Rights of Trustee

  	
  83

  
	
  Section 7.03.

  	
  Individual Rights of
  Trustee

  	
  85

  
	
  Section 7.04.

  	
  Trustee’s Disclaimer

  	
  85

  
	
  Section 7.05.

  	
  Notice of Defaults

  	
  85

  
	
  Section 7.06.

  	
  Reports by Trustee to
  Holders of the Notes

  	
  85

  
	
  Section 7.07.

  	
  Compensation and Indemnity

  	
  86

  
	
  Section 7.08.

  	
  Replacement of Trustee

  	
  87

  
	
  Section 7.09.

  	
  Successor Trustee by
  Merger, Etc.

  	
  88

  
	
  Section 7.10.

  	
  Eligibility;
  Disqualification

  	
  88

  
	
  Section 7.11.

  	
  Preferential Collection of
  Claims Against Issuers

  	
  88

  
	
   

  	
   

  	
   

  
	
  ARTICLE 8 LEGAL DEFEASANCE AND COVENANT DEFEASANCE

  	
  88

  
	
  Section 8.01.

  	
  Option to Effect Legal
  Defeasance or Covenant Defeasance

  	
  88

  
	
  Section 8.02.

  	
  Legal Defeasance and
  Discharge

  	
  89

  
	
  Section 8.03.

  	
  Covenant Defeasance

  	
  89

  
	
  Section 8.04.

  	
  Conditions to Legal
  Defeasance or Covenant Defeasance

  	
  90

  

 

ii

 

TABLE OF
CONTENTS

 

	
   

  	
   

  	
  Page

  
	
   

  	
   

  	
   

  
	
  Section 8.05.

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

  	
  91

  
	
  Section 8.06.

  	
  [Intentionally omitted]

  	
  92

  
	
  Section 8.07.

  	
  Reinstatement

  	
  92

  
	
   

  	
   

  	
   

  
	
  ARTICLE 9 AMENDMENT, SUPPLEMENT AND WAIVER

  	
  92

  
	
  Section 9.01.

  	
  Without Consent of Holders
  of Notes

  	
  92

  
	
  Section 9.02.

  	
  With Consent of Holders of
  Notes

  	
  93

  
	
  Section 9.03.

  	
  Compliance with Trust
  Indenture Act

  	
  95

  
	
  Section 9.04.

  	
  Revocation and Effect of
  Consents

  	
  95

  
	
  Section 9.05.

  	
  Notation or Exchange of
  Notes

  	
  95

  
	
  Section 9.06.

  	
  Trustee to Sign
  Amendments, Etc.

  	
  95

  
	
  Section 9.07.

  	
  Effect of Supplemental
  Indentures

  	
  96

  
	
   

  	
   

  	
   

  
	
  ARTICLE 10 GUARANTEES

  	
  96

  
	
  Section 10.01.

  	
  Guarantees

  	
  96

  
	
  Section 10.02.

  	
  Limitation of Guarantor’s
  Liability

  	
  97

  
	
  Section 10.03.

  	
  Execution and Delivery of
  Notations of Guarantees

  	
  98

  
	
  Section 10.04.

  	
  [Intentionally omitted]

  	
  98

  
	
  Section 10.05.

  	
  Releases

  	
  98

  
	
  Section 10.06.

  	
  “Trustee” to Include
  Paying Agent

  	
  99

  
	
   

  	
   

  	
   

  
	
  ARTICLE 11 SATISFACTION AND DISCHARGE

  	
  99

  
	
  Section 11.01.

  	
  Satisfaction and Discharge

  	
  99

  
	
  Section 11.02.

  	
  Application of Trust

  	
  101

  
	
  Section 11.03.

  	
  Repayment of the Issuers

  	
  101

  
	
  Section 11.04.

  	
  Reinstatement

  	
  101

  
	
   

  	
   

  	
   

  
	
  ARTICLE 12 MISCELLANEOUS

  	
  102

  
	
  Section 12.01.

  	
  Trust Indenture Act
  Controls

  	
  102

  
	
  Section 12.02.

  	
  Notices

  	
  102

  
	
  Section 12.03.

  	
  Communication by Holders
  of Notes with Other Holders of Notes

  	
  103

  
	
  Section 12.04.

  	
  Certificate and Opinion as
  to Conditions Precedent

  	
  103

  
	
  Section 12.05.

  	
  Statements Required in
  Certificate or Opinion

  	
  104

  
	
  Section 12.06.

  	
  Rules by Trustee and
  Agents

  	
  104

  
	
  Section 12.07.

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

  	
  105

  
	
  Section 12.08.

  	
  Governing Law

  	
  105

  
	
  Section 12.09.

  	
  No Adverse Interpretation
  of Other Agreements

  	
  105

  
	
  Section 12.10.

  	
  Successors

  	
  105

  
	
  Section 12.11.

  	
  Severability

  	
  105

  
	
  Section 12.12.

  	
  Counterpart Originals

  	
  105

  
	
  Section 12.13.

  	
  Table of Contents,
  Headings, Etc.

  	
  105

  

 

iii

 

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

  

 

iv

 

THIS
INDENTURE dated as of May 26, 2009 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.

 

“2004 Notes Issue Date” means October 19, 2004.

 

“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 

 

[Indenture]

 

 

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.

 

“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 or sale 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

 

(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 leaseback
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 leaseback 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 2004 Notes Issue Date.

 

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

 

“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.

 

7

 

“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 Thomson BankWatch 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 

 

8

 

phrase identified by footnote
3 thereto and shall not have the “Schedule of Exchanges of Interests in the
Global Note” attached thereto.

 

“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 the
Partnership, measured by voting power rather than number of shares, at a time
when the Partnership 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 Beneficially
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.

 

9

 

“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)           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.

 

10

 

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)           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

 

11

 

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 Credit Agreement, dated
February 20, 2008 and as amended on January 28, 2009, among the
Partnership, 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 

 

12

 

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.

 

“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).

 

“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.

 

13

 

“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).

 

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

 

14

 

(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.

 

“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.

 

15

 

“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 correlative 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.

 

16

 

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

 

(1)           in respect of borrowed
money;

 

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

 

(3)           in respect of bankers’
acceptances;

 

(4)           representing Capital Lease
Obligations;

 

(5)           representing all
Attributable Debt of such Person in respect of any sale and leaseback
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.

 

17

 

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.

 

“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, Wachovia Capital Markets, LLC, Barclays Capital, Inc.,
Deutsche Bank Securities Inc. and U.S. Bancorp Investments, Inc.

 

“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 

 

18

 

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 May 26, 2009.

 

“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, Dallas, Texas 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.

 

“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) 

 

19

 

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, (3) the
Partnership and (4) each Person which is a direct or indirect Subsidiary
of the Partnership.

 

“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 

 

20

 

(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 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.

 

21

 

“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 May 20, 2009 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.

 

“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 2004 Notes 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 

 

22

 

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:

 

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

 

(2)           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);

 

(3)           any Investment in cash or Cash
Equivalents;

 

(4)           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 

 

23

 

to, or is liquidated into,
the Partnership or a Restricted Subsidiary of the Partnership;

 

(5)           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;

 

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

 

(7)           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;

 

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

 

(9)           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 2004 Notes 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 passu with 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;

 

24

 

(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 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;

 

25

 

(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” 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 

 

26

 

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 any agency or
political subdivision thereof or any 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.

 

“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.

 

27

 

“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.

 

28

 

“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.

 

“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)           Basin Pipeline L.L.C., MarkWest
Blackhawk, L.L.C., MarkWest Energy Appalachia, L.L.C., MarkWest Energy East
Texas Gas Company, L.L.C., MarkWest Energy GP, L.L.C.,  MarkWest Energy Operating Company, L.L.C.,
MarkWest Gas Marketing, L.L.C., MarkWest Gas Services, L.L.C., MarkWest
Hydrocarbon, Inc., MarkWest Javelina Company, L.L.C., MarkWest Javelina
Pipeline Company, L.L.C., MarkWest Liberty Gas Gathering, L.L.C., MarkWest
Marketing, L.L.C., MarkWest McAlester, L.L.C., MarkWest Michigan Pipeline
Company, L.L.C., MarkWest New Mexico, L.L.C., MarkWest Pinnacle, L.L.C.,
MarkWest Pipeline Company, L.L.C., MarkWest PNG Utility, L.L.C., MarkWest Power
Tex, L.L.C., MarkWest Texas PNG Utility, L.L.C., MarkWest Oklahoma Gas Company,
L.L.C., Mason Pipeline Limited Liability Company,  Matrex, L.L.C. and West Shore Processing
Company, L.L.C.; 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;

 

29

 

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.

 

“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.

 

30

 

“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 MarkWest Liberty Midstream & Resources, L.L.C., a Delaware
limited liability company, and any other 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.

 

“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 

 

31

 

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.

 

32

 

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;

 

“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 minimum denominations of $2,000 or integral
multiples of $1,000 in excess thereof.

 

33

 

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.

 

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) $150,000,000
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 

 

34

 

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 in the continental United
States 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 at the Corporate Trust Office of the Trustee.

 

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.

 

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 

 

35

 

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.

 

36

 

(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 

 

37

 

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.

 

(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

 

38

 

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.

 

(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 

 

39

 

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;

 

40

 

(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 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.

 

41

 

(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:  ONE YEAR] [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 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 

 

42

 

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 

 

43

 

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.”

 

(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).

 

44

 

(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 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 

 

45

 

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.

 

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).

 

46

 

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 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, the special record date 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 

 

47

 

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 $2,000 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.

 

48

 

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.

 

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 (if then determined and otherwise the basis for its determination);

 

(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.

 

49

 

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.

 

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.

 

50

 

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)                                 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.

 

The
Partnership shall calculate such redemption price and set it forth on an
Officers’ Certificate delivered to the Trustee prior to the redemption date.

 

(c)                                  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 

 

51

 

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;

 

(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 minimum denominations of $2,000 or integral multiples of $1,000 in
excess thereof, shall be purchased); and

 

52

 

(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 City
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 minimum principal amount of $2,000 or an integral multiple of
$1,000 in excess 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 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 

 

53

 

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 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 in the continental
United States 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 

 

54

 

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.

 

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 $2,000 or an integral multiple
of $1,000 in excess 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 due 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 

 

55

 

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, 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

 

56

 

(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 City 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 $2,000 or an integral multiple
of $1,000 in excess 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.

 

57

 

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)                                     the Partnership
(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;

 

(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;

 

58

 

(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 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.

 

59

 

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 this clause (iv) and
clauses (i) through (iii) 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 

 

60

 

Partnership from any Person (other than to a
Restricted Subsidiary of the Partnership) made after the 2004 Notes Issue Date
or (ii) substantially concurrent issuance and sale (other than to a
Restricted Subsidiary of the Partnership) made after the 2004 Notes 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 2004 Notes 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 2004 Notes Issue
Date, plus

 

(iii)                               to the extent
that any Restricted Investment that was made after the 2004 Notes 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 2004 Notes 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 

 

61

 

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
2004 Notes 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.

 

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

 

62

 

(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 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.

 

63

 

(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 extend, refinance, renew, replace, defease
or refund 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 extend, refinance, renew, replace, defease or refund any
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 

 

64

 

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

 

(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 neither the Partnership nor 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 

 

65

 

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
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, 

 

66

 

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;

 

(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;

 

67

 

(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 

 

68

 

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.

 

(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)                              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;

 

(v)                                 sales
of Equity Interests (other than Disqualified Equity) to Affiliates of the
Partnership; and

 

(vi)                              transactions
effected in accordance with the terms of the agreements that are identified in
Schedule B to this Indenture, as each such agreement is in effect on the date
of this Indenture, and any amendment or extension of such agreement so long as
the terms of such amendment or extension, taken as a whole, are not less
advantageous the Partnership or the relevant Restricted Subsidiary (as
determined by the Board of  Directors of
the General Partner in its reasonable good faith judgment) in any material
respect than the agreement so amended or extended.

 

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 be released in accordance with the terms and
subject to the conditions of Section 10.05.

 

69

 

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.

 

(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 

 

70

 

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 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.

 

71

 

(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 

 

72

 

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 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.

 

Section 4.20.                             Calculation of Original
Issue Discount.

 

The Issuers shall file with the
Trustee within 30 days of the end of each calendar year specific information
relating to original issue discount as may be required under the Code. The
Issuer has determined that, for purposes of calculating original issue discount
and making any other determinations relating to original issue discount, each
accrual period shall end on the semi-annual interest date of May 1 and November 1
of each year, or if any such day is not a Business Day (as defined herein), on
the next succeeding Business Day.

 

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 

 

73

 

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;

 

(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 

 

74

 

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 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 

 

75

 

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;

 

76

 

(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,

 

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

 

77

 

(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 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 

 

78

 

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

 

79

 

(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.

 

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 

 

80

 

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

 

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 

 

81

 

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.

 

(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.  

 

82

 

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.

 

83

 

(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 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.

 

84

 

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 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.

 

85

 

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 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 

 

86

 

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 

 

87

 

Trustee hereunder have been paid and subject to the Lien provided for 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 or association, the successor
corporation or association 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 or association 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.

 

88

 

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 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

 

89

 

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
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;

 

90

 

(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 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.

 

91

 

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;

 

92

 

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

 

(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.

 

93

 

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 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).

 

94

 

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.

 

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

 

95

 

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
and that all conditions precedent have been satisfied.

 

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 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

 

96

 

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

 

97

 

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.

 

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

 

98

 

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 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

 

99

 

(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

 

(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

 

100

 

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,

 

101

 

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 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.

1515 Arapahoe St., Tower 2, Suite 700

Denver, Colorado  80202

Telecopier No.: (303) 662-8870

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

1445 Ross Avenue – Second Floor

Dallas, Texas 
75202-2812

Attention: 
Corporate Trust Department

Telecopier No.:  (214) 777-4086

 

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

 

102

 

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 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

 

103

 

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.

 

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.

 

104

 

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

 

No 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.

 

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]

 

105

 

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

 

Issuers:

 

	
  MARKWEST ENERGY FINANCE
  CORPORATION

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By: 

  	
  /s/ Nancy K. Buese

  	
   

  	
   

  
	
  Name: Nancy Buese

  	
   

  	
   

  
	
  Title: Senior Vice
  President and Chief Financial Officer

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  MARKWEST ENERGY PARTNERS,
  L.P.

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By: 

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

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  	
   

  	
   

  
	
   

  	
  Name: Nancy Buese

  	
   

  	
   

  
	
   

  	
  Title: Senior Vice
  President and Chief Financial Officer

  	
   

  	
   

  
						

 

[Indenture]

 

 

	
   

  	
   

  	
  Subsidiary Guarantors:

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  MARKWEST
  HYDROCARBON, INC.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  MARKWEST
  ENERGY GP, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  MASON
  PIPELINE LIMITED LIABILITY COMPANY

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Hydrocarbon, Inc.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Sole Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  

 

[Indenture]

 

 

	
   

  	
   

  	
  MARKWEST ENERGY OPERATING
  COMPANY, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and
  Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  BASIN PIPELINE L.L.C.

  
	
   

  	
   

  	
  WEST SHORE PROCESSING COMPANY, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Sole Member and Manager

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  

 

[Indenture]

 

 

	
   

  	
   

  	
  MARKWEST BLACKHAWK, L.L.C.

  MARKWEST ENERGY APPALACHIA, L.L.C.

  MARKWEST ENERGY EAST TEXAS GAS COMPANY,  L.L.C.

  MARKWEST GAS MARKETING, L.L.C.

  MARKWEST GAS SERVICES, L.L.C.

  MARKWEST JAVELINA COMPANY, L.L.C.

  MARKWEST JAVELINA PIPELINE COMPANY, L.L.C.

  MARKWEST LIBERTY GAS GATHERING, L.L.C.

  MARKWEST MARKETING, L.L.C.

  MARKWEST NEW MEXICO, L.L.C.

  MARKWEST PINNACLE, L.L.C.

  MARKWEST PIPELINE COMPANY, L.L.C.

  MARKWEST PNG UTILITY, L.L.C.

  MARKWEST POWER TEX, L.L.C.

  MARKWEST TEXAS PNG UTILITY, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Operating Company, L.L.C., its Sole Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  

 

[Indenture]

 

 

	
   

  	
   

  	
  MARKWEST MICHIGAN PIPELINE
  COMPANY, L.L.C.
  MARKWEST OKLAHOMA GAS COMPANY, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  

 

[Indenture]

 

 

	
   

  	
   

  	
  MATREX,
  L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  Basin Pipeline L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Sole Member and Manager

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Sole Member and Manager

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  MARKWEST
  MCALESTER, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

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

  
	
   

  	
   

  	
   

  	
   

  	
  its Sole Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  By:

  	
   MarkWest
  Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name: 

  	
  Nancy Buese

  
	
   

  	
   

  	
  Title: 

  	
  Senior Vice President and Chief Financial Officer

  

 

[Indenture]

 

 

	
   

  	
   

  	
  Trustee:

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  WELLS FARGO BANK, NATIONAL ASSOCIATION, as
  Trustee

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By: 

  	
  /s/ Patrick Giordano

  
	
   

  	
   

  	
  Name: Patrick Giordano

  
	
   

  	
   

  	
  Title: Vice President

  

 

[Indenture]

 

 

SCHEDULE A

 

Schedule of Subsidiary
Guarantors

 

MarkWest Energy Operating
Company, L.L.C.

MarkWest Hydrocarbon, Inc.

MarkWest Energy GP, L.L.C.

Basin Pipeline L.L.C.

MarkWest Blackhawk, L.L.C.

MarkWest Energy Appalachia,
L.L.C.

MarkWest Energy East Texas
Gas Company, L.L.C.

MarkWest Gas Marketing,
L.L.C.

MarkWest Gas Services,
L.L.C.

MarkWest Javelina Company,
L.L.C.

MarkWest Javelina Pipeline
Company, L.L.C.

MarkWest Michigan Pipeline
Company, L.L.C.

MarkWest New Mexico, L.L.C.

MarkWest Pinnacle, L.L.C.

MarkWest Pipeline Company,
L.L.C.

MarkWest PNG Utility, L.L.C.

MarkWest Power Tex, L.L.C.

MarkWest Texas PNG Utility,
L.L.C.

MarkWest Oklahoma Gas
Company, L.L.C.

Mason Pipeline Limited
Liability Company

Matrex, L.L.C.

MarkWest Liberty Gas
Gathering, L.L.C.

MarkWest Marketing, L.L.C.

MarkWest McAlester, L.L.C.

West Shore Processing
Company, L.L.C.

 

 

SCHEDULE B

 

Certain Agreements

 

1.                                       Contribution
Agremeent, dated as of January 22, 2009, among MarkWest Liberty Gas
Gathering, L.L.C., M&R MWE Liberty, LLC and MarkWest Liberty Midstream &
Resources, L.L.C.

 

2.                                       Fractionation
and Natural Gas Liquids Purchase Agreement, dated as of February 27, 2009,
between MarkWest Liberty Midstream & Resources, L.L.C. and MarkWest Hydrocarbon, Inc.

 

3.                                       Services
Agreement, dated as of February 27, 2009, among MarkWest Hydrocarbon, Inc.,
MarkWest Liberty Gas Gathering, L.L.C. and MarkWest Liberty Midstream &
Resources, L.L.C.

 

4.                                       Services
Agreement, dated as of May 1, 2009, between MarkWest Hydrocarbon, Inc.
and MarkWest Pioneer, L.L.C.

 

 

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)

 

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 

 

(1) This is included in Global Notes
only.

 

1

 

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:  ONE
YEAR] [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 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)

 

THIS NOTE IS BEING ISSUED WITH ORIGINAL ISSUE
DISCOUNT FOR UNITED STATES FEDERAL INCOME TAX PURPOSES. FOR PURPOSES OF ANY
CALCULATIONS RELATING TO ORIGINAL ISSUE DISCOUNT, EACH ACCRUAL PERIOD SHALL END
ON THE SEMI-ANNUAL INTEREST DATE OF MAY 1 AND NOVEMBER 1 OF EACH YEAR, OR
IF ANY SUCH DAY IS NOT A BUSINESS DAY (AS DEFINED IN THE INDENTURE), ON THE
NEXT SUCCEEDING BUSINESS DAY. FOR INFORMATION REGARDING THE ISSUE PRICE, THE
TOTAL AMOUNT OF ORIGINAL ISSUE DISCOUNT, THE ISSUE DATE, AND THE YIELD TO
MATURITY OF THIS SECURITY, PLEASE CONTACT THE CHIEF FINANCIAL OFFICER OF
MARKWEST ENERGY PARTNERS, L.P. AT 1515 ARAPAHOE ST., TOWER 2, SUITE 700,
DENVER, COLORADO 80202 (OR TELEPHONE HER AT (303) 925-9210).

 

(2) Legend appears only on the Series A
Notes

 

2

 

	
  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.

 

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.

 

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 

  	
   

  	
  MARKWEST
  ENERGY PARTNERS, L.P.

  
	
  CORPORATION

  	
   

  	
   

  
	
   

  	
   

  	
  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

 

(3) This is included in Global Notes
only.

 

3

 

	
  By:

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
  Authorized Signatory

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Date of Authentication:
                  
        ,

  	
   

  	
   

  	
   

  

 

4

 

[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 November 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 November 1, 2009. 
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 

 

5

 

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 May 26, 2009 (“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.

 

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)           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.

 

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 $2,000 or an
integral multiple of $1,000 in 

 

6

 

excess 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 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 $2,000 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 minimum denominations of $2,000 or integral multiples of $1,000 in
excess thereof.  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.

 

7

 

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 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 

 

8

 

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 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.

 

9

 

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.

1515 Arapahoe St., Tower 2, Suite 700

Denver, Colorado 80202

Attention: Chief Financial Officer

 

10

 

[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.

 

11

 

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 a minimum of $2,000 or an integral multiple of $1,000 in
excess thereof):

 

	
  $

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  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.

 

12

 

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.

 

13

 

EXHIBIT B

 

FORM OF CERTIFICATE OF TRANSFER

 

Wells Fargo Bank, National
Association

1445 Ross Avenue — Second Floor

Dallas, Texas  75202-2812

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 May 26, 2009 (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 

 

1

 

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 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 

 

2

 

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.

 

(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, Wachovia Capital Markets, LLC, Barclays Capital, Inc.,
Deutsche Bank Securities Inc. and U.S. Bancorp Investments, Inc.
(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.

 

3

 

	
  [Insert Name
  of Transferor]

  
	
   

  
	
  By:

  	
   

  	
   

  
	
  Name:

  	
   

  	
   

  
	
  Title:

  	
   

  	
   

  
	
   

  
	
  Dated:
                  
        ,

  
					

 

 

cc: Issuers

 

Initial Purchasers

 

4

 

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.

 

5

 

EXHIBIT C

 

FORM OF CERTIFICATE OF EXCHANGE

 

Wells Fargo Bank, National
Association

1445 Ross Avenue — Second Floor

Dallas, Texas  75202-2812

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 May 26, 2009 (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 

 

1

 

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, Wachovia Capital Markets, LLC, Barclays Capital, Inc.,
Deutsche Bank Securities Inc. and U.S. Bancorp Investments, Inc.
(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 Owner]

  
	
   

  
	
  By:

  	
   

  	
   

  
	
  Name:

  	
   

  	
   

  
	
  Title:

  	
   

  	
   

  
	
   

  
	
  Dated:
                  
        ,

  
					

 

cc:           Issuers

Initial Purchasers

 

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.

 

1

 

	
   

  	
  Subsidiary Guarantors:

  
	
   

  	
   

  
	
   

  	
  MARKWEST
  HYDROCARBON, INC.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  MARKWEST ENERGY GP, L.L.C.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  MASON PIPELINE LIMITED
  LIABILITY COMPANY

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Hydrocarbon, Inc.,

  
	
   

  	
   

  	
   

  	
  its Sole Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
					

 

2

 

	
   

  	
   

  	
  MARKWEST ENERGY OPERATING
  COMPANY, L.L.C.

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
  its 
  Managing Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  BASIN
  PIPELINE L.L.C.

  WEST SHORE PROCESSING COMPANY, L.L.C.

  
	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
  its Sole Member and Manager

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  

 

3

 

	 
	
   

  	
  MARKWEST BLACKHAWK, L.L.C.

  MARKWEST ENERGY APPALACHIA, L.L.C.

  MARKWEST ENERGY EAST TEXAS GAS COMPANY,  L.L.C.

  MARKWEST GAS MARKETING, L.L.C.

  MARKWEST GAS SERVICES, L.L.C.

  MARKWEST JAVELINA COMPANY, L.L.C.

  MARKWEST JAVELINA PIPELINE COMPANY, L.L.C.

  MARKWEST LIBERTY GAS GATHERING, L.L.C.

  MARKWEST MARKETING, L.L.C.

  MARKWEST NEW MEXICO, L.L.C.

  MARKWEST PINNACLE, L.L.C.

  MARKWEST PIPELINE COMPANY, L.L.C.

  MARKWEST PNG UTILITY, L.L.C.

  MARKWEST POWER TEX, L.L.C.

  MARKWEST TEXAS PNG UTILITY, L.L.C.

  	 

	 
	
   

  	
   

  	 

	
   

  	
  By:

  	
   

  
	
   

  	
   

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
  its Sole Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
						

 

4

 

	
   

  	
  MARKWEST MICHIGAN PIPELINE
  COMPANY, L.L.C.

  MARKWEST OKLAHOMA GAS COMPANY, L.L.C.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy Operating Company, L.L.C.,

  
	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy Partners, L.P.,

  
	
   

  	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  MarkWest Energy GP, L.L.C.,

  
	
   

  	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief Financial Officer

  
					

 

5

 

	
   

  	
  MATREX,
  L.L.C.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  Basin Pipeline L.L.C.,

  
	
   

  	
   

  	
  its Sole Member and
  Manager

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Operating
  Company, L.L.C.,

  
	
   

  	
   

  	
  its Sole Member and
  Manager

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Partners,
  L.P.,

  
	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy GP,
  L.L.C.,

  
	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and
  Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  MARKWEST
  MCALESTER, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

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

  
	
   

  	
   

  	
  its Sole Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Operating
  Company, L.L.C., 

  
	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Partners,
  L.P.,

  
	
   

  	
   

  	
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy GP,
  L.L.C., 

  
	
   

  	
   

  	
  its General Partner

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
   

  
	
   

  	
  Name:

  	
  Nancy Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and
  Chief Financial Officer

  

 

6

 

EXHIBIT E

 

FORM OF CERTIFICATE FROM

ACQUIRING INSTITUTIONAL ACCREDITED INVESTOR

 

MarkWest Energy Partners,
L.P.

MarkWest Energy Finance
Corporation

1515 Arapahoe St., Tower 2, Suite 700

Denver, Colorado 80202

 

Wells
Fargo Bank, National Association

1445
Ross Avenue — Second Floor

Dallas,
Texas 75202-2812

 

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 May 26, 2009 (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) [ ] a beneficial interest in a Global
Note, or

 

(b) [ ] 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) 

 

1

 

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 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:
                
      ,

 

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 May 26, 2009 (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 

 

A-2

 

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.

 

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

 

 

1

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