Exhibit
4.1


 


Execution Version


 


MARKWEST ENERGY PARTNERS, L.P.


 


AND


 


MARKWEST ENERGY FINANCE
CORPORATION


 


AND


 


THE SUBSIDIARY GUARANTORS NAMED
HEREIN,


 


AND


 


WELLS FARGO BANK, NATIONAL
ASSOCIATION,


 


as Trustee


 


 


SEVENTH SUPPLEMENTAL INDENTURE


 


Dated
as of November 2, 2010


 


to


 


Indenture


 


Dated as of October 25,
2004


 


6.875% Senior Notes due 2014


 

















 


THIS SEVENTH SUPPLEMENTAL
INDENTURE (this “Supplemental Indenture”), dated as of  November 2, 2010, is by and among
MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Company”), MarkWest Energy Finance Corporation, a Delaware
corporation (“Finance Corp.” and, together with the Company, the “Issuers”),
the Subsidiary Guarantors (as defined in the Indenture referred to herein), and
Wells Fargo Bank, National Association, as trustee (the “Trustee”).


 


WHEREAS, the Issuers, the Subsidiary
Guarantors and the Trustee are parties to that certain Indenture dated as of October 25,
2004 (the “Original Indenture”), relating to the
Company’s 6.875% Senior Notes due 2014 (the “Notes”),
and the Original Indenture has been amended and supplemented by six
Supplemental Indentures (the Original Indenture, as so amended and
supplemented, being referred to herein as the “Indenture”);


 


WHEREAS, $225,000,000 aggregate principal
amount of Notes are currently outstanding;


 


WHEREAS, Section 9.02 of the
Indenture provides that, 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 tender offer for Notes), the
Issuers, the Subsidiary Guarantors and the Trustee may enter into an indenture
supplemental to the Indenture for the purpose of amending or supplementing the
Indenture or the Notes (subject to certain exceptions);


 


WHEREAS, the Issuers desire and have
requested the Trustee to join with them and the Subsidiary Guarantors in
entering into this Supplemental Indenture for the purpose of amending the
Indenture and the Notes in certain respects as permitted by Section 9.02
of the Indenture;


 


WHEREAS, the Company has been
soliciting consents to this Supplemental Indenture upon the terms and subject
to the conditions set forth in its Offer to Purchase and Consent Solicitations
Statement dated October 18, 2010 and the related Consent and Letter of
Transmittal (which together, including any amendments, modifications or
supplements thereto, constitute the “Tender Offer”);


 


WHEREAS, (1) the Company has
received the consent of the Holders of at least a majority in principal amount
of the outstanding Notes (excluding any Notes owned by the Company or any of
its Affiliates), all as certified by an Officers’ Certificate delivered to the
Trustee simultaneously with the execution and delivery of this Supplemental
Indenture, (2) the Company has delivered to the Trustee simultaneously
with the execution and delivery of this Supplemental Indenture an Opinion of
Counsel relating to this Supplemental Indenture as contemplated by Section 9.06
of the Indenture and (3) the Issuers and the Subsidiary Guarantors have
satisfied all other conditions required under Article 9 of the Indenture
to enable the Issuers, the Subsidiary Guarantors and the Trustee to enter into
this Supplemental Indenture.


 


NOW, THEREFORE, in consideration of
the above premises, each party hereby agrees, for the benefit of the others and
for the equal and ratable benefit of the Holders of the Notes, as follows:


 


2

















 


ARTICLE I


 


AMENDMENTS TO INDENTURE AND NOTES


 


Section 1.1 Amendments to Articles 3, 4, 5 and 6.
The Indenture is hereby amended by deleting the following Sections or clauses
of the Indenture and all references and definitions related thereto in their
entirety:


 


Section 3.09 (Offer to Purchase
by Application of Net Proceeds); Section 4.03(c) (Compliance
Certificate);


Section 4.04 (Taxes);


Section 4.05 (Stay, Extension
and Usury Laws);


Section 4.06 (Change of
Control);


Section 4.07 (Asset Sales);


 


Section 4.08 (Restricted
Payments);


Section 4.09 (Incurrence of
Indebtedness and Issuance of Disqualified Equity); Section 4.10 (Liens);


Section 4.11 (Dividend and
Other Payment Restrictions Affecting Subsidiaries); Section 4.12
(Transactions With Affiliates);


Section 4.13 (Additional
Subsidiary Guarantees);


Section 4.14 (Designation of
Restricted and Unrestricted Subsidiaries);


Section 4.15 (Business
Activities);


Section 4.16 (Sale and
Leaseback Transactions);


Section 4.17 (Payments for
Consent);


Section 4.18 (Reports), except
as required by Section 314a of the TIA;


Clauses (iii) and (iv) of Section 5.01(a) (Merger,
Consolidation, or Sale of Assets); and Clauses (f) and (g) Section 6.01(a) (Events
of Default).


 


Section 1.2 Amendments to Notes. The
Notes are hereby amended to delete all provisions inconsistent with the
amendments to the Indenture effected by this Supplemental Indenture.


 


ARTICLE II


 


MISCELLANEOUS PROVISIONS


 


Section 2.1 Defined Terms. For all
purposes of this Supplemental Indenture, except as otherwise defined or unless
the context otherwise requires, terms used in capitalized form in this
Supplemental Indenture and defined in the Indenture have the meanings specified
in the Indenture.


 


Section 2.2 Indenture. Except as amended
hereby, the Indenture and the Notes are in all respects ratified and confirmed
and all the terms shall remain in full force and effect. This Supplemental
Indenture shall form a part of the Indenture for all purposes, and every Holder
of Notes heretofore or hereafter authenticated and delivered under the
Indenture shall be bound hereby and all terms and conditions of both shall be
read together as though they constitute a 


 


3

















 


single instrument, except that in
the case of conflict the provisions of this Supplemental Indenture shall control.


 


Section 2.3 Governing Law. THIS
SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.


 


Section 2.4 Successors. All agreements
of the Issuers and the Subsidiary Guarantors in this Supplemental Indenture and
the Notes shall bind their respective successors. All agreements of the Trustee
in this Supplemental Indenture shall bind its successors.


 


Section 2.5 Duplicate Originals. All
parties may sign any number of copies of this Supplemental Indenture. Each
signed copy shall be an original, but all of them together shall represent the
same agreement. It is the express intent of the parties to be bound by the
exchange of signatures on this Supplemental Indenture via telecopy or other
form of electronic transmission.


 


Section 2.6 Severability. In case any
one or more of the provisions in this Supplemental Indenture or in the Notes
shall be held invalid, illegal or unenforceable, in any respect for any reason,
the validity, legality and enforceability of any such provision in every other
respect and of the remaining provisions shall not in any way be affected or
impaired thereby, it being intended that all of the provisions hereof shall be
enforceable to the full extent permitted by law.


 


Section 2.7 Trustee Disclaimer. The
Trustee accepts the amendments of the Indenture effected by this Supplemental
Indenture and agrees to execute the trust created by the Indenture as hereby
amended, but on the terms and conditions set forth in the Indenture, including
the terms and provisions defining and limiting the liabilities and
responsibilities of the Trustee, which terms and provisions shall in like
manner define and limit its liabilities and responsibilities in the performance
of the trust created by the Indenture as hereby amended, and without limiting
the generality of the foregoing, the Trustee shall not be responsible in any
manner whatsoever for or with respect to any of the recitals or statements
contained herein, all of which recitals or statements are made solely by the
Issuers and the Subsidiary Guarantors, and the Trustee makes no representation
with respect to any such matters. Additionally, the Trustee makes no
representations as to the validity or sufficiency of this Supplemental
Indenture.


 


Section 2.8 Effectiveness. The
provisions of this Supplemental Indenture shall be effective only upon
execution and delivery of this instrument by the parties hereto.
Notwithstanding the foregoing sentence, the provisions of this Supplemental
Indenture shall become operative only upon the purchase by the Company,
pursuant to the Tender Offer, of at least a majority in principal amount of the
outstanding Notes (excluding any Notes owned by the Company or any of its
Affiliates), with the result that the amendments to the Indenture effected by
this Supplemental Indenture shall be deemed to be revoked retroactive to the
date hereof if such purchase shall not occur. The Company shall notify the
Trustee promptly after the occurrence of such purchase or promptly after the Company
shall determine that such purchase will not occur.


 


Section 2.9 Endorsement and Change of Form of Notes.
Any Notes authenticated and delivered after the close of business on the date
that this Supplemental Indenture becomes operative in substitution for Notes
then outstanding and all Notes presented or delivered to the Trustee on and
after that date for such purpose shall be stamped, imprinted or otherwise
legended by the Company, with a notation as follows:


 


4

















 


“Effective as of November 2,
2010, certain restrictive covenants of the Company and certain Events of
Default have been eliminated or limited, as provided in the Seventh
Supplemental Indenture, dated as of November 2, 2010. Reference is hereby
made to such Seventh Supplemental Indenture, copies of which are on file with
the Trustee, for a description of the amendments made therein.”


 


Section 2.10 Effect of Headings. The Section headings
herein are for convenience only and shall not affect the construction thereof.


 


[THE REMAINDER OF THIS PAGE
IS INTENTIONALLY LEFT BLANK]


 


5

















 


IN WITNESS
WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly
executed as of the day and year written above.


 


	
   

  	
  Issuers:

  
	
   

  	
   

  
	
   

  	
  MARKWEST ENERGY PARTNERS, L.P.

  
	
   

  	
   

  
	
   

  	
  By: MarkWest Energy GP, L.L.C.,
  its general partner

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  MARKWEST ENERGY FINANCE
  CORPORATION

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature Page to Seventh Supplemental Indenture


 

















 


	
   

  	
  Subsidiary Guarantors:

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  MARKWEST ENERGY GP, L.L.C.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  MARKWEST HYDROCARBON, INC.

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
  Name:

  	
  Nancy K. 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 K. Buese

  
	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature Page to Seventh Supplemental 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 K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  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 K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature Page to Seventh Supplemental Indenture


 

















 


	
   

  	
   

  	
  MARKWEST BLACKHAWK, L.L.C. 

  
	
   

  	
   

  	
  MARKWEST ENERGY APPALACHIA,
  L.L.C.

  
	
   

  	
   

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

  
	
   

  	
   

  	
  MARKWEST GAS MARKETING, L.L.C.x

  
	
   

  	
   

  	
  MARKWEST GAS SERVICES, L.L.C. 

  
	
   

  	
   

  	
  MARKWEST JAVELINA COMPANY,
  L.L.C.

  
	
   

  	
   

  	
  MARKWEST JAVELINA PIPLELINE COMPANY,
  L.L.C.

  
	
   

  	
   

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

  
	
   

  	
   

  	
  MARKWEST NEW MEXICO, L.L.C. 

  
	
   

  	
   

  	
  MARKWEST PIONEER, 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 K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature Page to Seventh Supplemental Indenture


 

















 


	
   

  	
   

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

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

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

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

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

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  MATREX, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  West Shore Processing Company
  L.L.C., its Sole Member and Manager

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

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

  
	
   

  	
   

  	
   

  
	
   

  	
  By: 

  	
  MarkWest Energy Partners, L.P.,
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

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

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature Page to Seventh Supplemental
Indenture


 

















 


	
   

  	
   

  	
  MARKWEST MCALESTER, L.L.C.

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Oklahoma Gas Company,
  L.L.C., its Sole Member

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

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

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  MarkWest Energy Partners, L.P.,
  its Managing Member

  
	
   

  	
   

  	
   

  
	
   

  	
   

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

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
  By:

  	
  /s/ Nancy K. Buese

  
	
   

  	
   

  	
  Name:

  	
  Nancy K. Buese

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President and Chief
  Financial Officer

  



 


Signature
Page to Seventh Supplemental Indenture


 

















 


	
   

  	
  WELLS FARGO BANK, NATIONAL
  ASSOCIATION, as
  Trustee

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Patrick T. Giodano

  
	
   

  	
  Name:

  	
  Patrick T. Giordano

  
	
   

  	
  Title:

  	
  Vice President

  



 


Signature
Page to Seventh Supplemental Indenture