8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): December 3, 2015

MARKWEST ENERGY PARTNERS, L.P.

(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization) 001-31239
(Commission File Number) 27-0005456
(I.R.S. Employer
Identification Number)

1515 Arapahoe Street, Tower 1, Suite 1600, Denver CO 80202

(Address of principal executive offices)

Registrant’s telephone number, including area code: 303-925-9200

Not Applicable.

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

oWritten Communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-Commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-Commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 1.01.    Entry into a Material Definitive Agreement.

On December 3, 2015, MarkWest Energy Partners, L.P. (the “Partnership”), MarkWest Energy Finance Corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), certain subsidiary guarantors, and Wells Fargo Bank, National Association, as trustee (the “Trustee”), entered into Supplemental Indentures (the “Supplemental Indentures”) respecting amendments to the Indentures governing the Issuers’ outstanding 5.5% Senior Notes due 2023, 4.5% Senior Notes due 2023, 4.875% Senior Notes due 2024 and 4.875% Senior Notes due 2025 (collectively, the “Notes”) following the Issuers’ receipt of requisite consents of the holders of the Notes pursuant to consent solicitations in respect of the Notes that commenced on November 19, 2015 (the “Consent Solicitations”). The Supplemental Indentures eliminate most of the restrictive covenants and certain default provisions respecting the Notes. The Supplemental Indentures are effective upon execution but will only become operative upon consummation of the Consent Solicitations.

Copies of the Supplemental Indentures are filed as Exhibits 4.1, 4.2, 4.3 and 4.4 to this Form 8-K and are incorporated herein by reference. The description of the Supplemental Indentures is qualified in its entirety by the terms of the respective Indentures and the Supplemental Indentures.

ITEM 7.01.    Regulation FD Disclosure.

On December 4, 2015 the Partnership issued a press release announcing the successful completion of the Consent Solicitations.  A copy of the press release is furnished herewith as Exhibit 99.1.

The information contained in this Item 7.01 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended or incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing.

ITEM 9.01.    Financial Statements and Exhibits.

(d)Exhibits.

Exhibit No.	Description of Exhibit
4.1	Sixteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.2	Seventeenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.3	Eighteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.4	Nineteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
99.1	Press release dated December 4, 2015.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	MARKWEST ENERGY PARTNERS, L.P.
			(Registrant)
	By:	MarkWest Energy GP, L.L.C.,
		Its General Partner
Date: December 4, 2015	By:	/s/ NANCY K. BUESE
		Nancy K. Buese
		Executive Vice President and Chief Financial Officer

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EXHIBIT INDEX

Exhibit No.	Description of Exhibit
4.1	Sixteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.2	Seventeenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.3	Eighteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
4.4	Nineteenth Supplemental Indenture, dated as of December 3, 2015, to Indenture dated as of November 2, 2010, by and among the Issuers, certain subsidiary guarantors named therein, and Wells Fargo Bank, National Association, as trustee.
99.1	Press release dated December 4, 2015.

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EX-4.1

Exhibit 4.1

MARKWEST ENERGY PARTNERS, L.P.

AND

MARKWEST ENERGY FINANCE CORPORATION

AND

THE SUBSIDIARY GUARANTORS NAMED HEREIN,

AND

WELLS FARGO BANK, NATIONAL ASSOCIATION,

as Trustee

SIXTEENTH SUPPLEMENTAL INDENTURE

Dated as of December 3, 2015

to

Indenture

Dated as of November 2, 2010

 5.5% Senior Notes due 2023

THIS SIXTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of December 3, 2015, 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 November 2, 2010, as supplemented by the Eighth Supplemental Indenture dated as of August 10, 2012 creating the Issuers’ 5.5% Senior Notes due 2023 (the “Notes”) and as further amended and supplemented in relation to the Notes (the “Indenture”);

WHEREAS, $750,000,000 aggregate principal amount of the Notes is currently outstanding;

WHEREAS, Section 10.02 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 an exchange offer for the 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 10.02 of the Indenture;

WHEREAS, the Issuers have been soliciting consents to this Supplemental Indenture upon the terms and subject to the conditions set forth in the Offering Memorandum and Consent Solicitation Statement (herein so called) of MPLX LP and the Company dated November 19, 2015 and the related Letter of Transmittal and Consent (which together, including any amendments, modifications or supplements thereto, govern the “Consent Solicitation” for the Notes); and

WHEREAS, (1) the Issuers have 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 10.06 of the Indenture and (3) the Issuers and the Subsidiary Guarantors have satisfied all other conditions required under Article X 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:

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ARTICLE I

AMENDMENTS TO INDENTURE AND NOTES

Section 1.1 Amendments to Articles 4, 5, 6 and 7. 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 4.09 (Offer to Purchase by Application of Net Proceeds);

Section 5.06 (Change of Control);

Section 5.07 (Asset Sales);

Section 5.08 ( Restricted Payments);

Section 5.09 (Incurrence of Indebtedness and Issuance of Disqualified Equity);

Section 5.11 (Dividend and Other Payment Restrictions Affecting Subsidiaries);

Section 5.12 (Transactions with Affiliates);

Section 5.13 (Additional Subsidiary Guarantees);

Section 5.15 (Business Activities of MarkWest Finance);

Section 5.16 (Sale and Leaseback Transactions);

Section 5.17 (Reports);

Clause (a)(iv) of Section 6.01 (Merger, Consolidation or Sale of Assets); and

Clauses (d) — (h) of Section 7.01 (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 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.

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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 closing of the Consent Solicitation and the related Exchange Offer (as defined in the Offering Memorandum and Consent Solicitation Statement), 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 closing shall not occur. The Company shall notify the Trustee promptly after the occurrence of such closing or promptly after the Company shall determine that such closing 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:

“Effective as of December 3, 2015, certain restrictive covenants of the Company and certain Events of Default have been eliminated or limited, as provided in the Sixteenth Supplemental Indenture, dated as of December 3, 2015. Reference is hereby made to such Sixteenth Supplemental Indenture, copies of which are on file with the Trustee, for a description of the amendments made therein.”

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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]

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

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C.

MARKWEST ENERGY APPALACHIA, L.L.C.

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

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

MARKWEST ENERGY WEST 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 MICHIGAN PIPELINE COMPANY, L.L.C.

MARKWEST MOUNTAINEER PIPELINE COMPANY, L.L.C.

MARKWEST NEW MEXICO, L.L.C.

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

MARKWEST TEXAS PNG UTILITY, L.L.C.

MARKWEST UTICA OPERATING COMPANY, L.L.C.

WEST SHORE PROCESSING COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

MARKWEST MCALESTER, L.L.C.
MARKWEST BUFFALO CREEK GAS COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Sixteenth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ John Stohlmann
Name:	John Stohlmann
Title:	Vice President

Signature Page to Sixteenth Supplemental Indenture

EX-4.2

Exhibit 4.2

MARKWEST ENERGY PARTNERS, L.P.

AND

MARKWEST ENERGY FINANCE CORPORATION

AND

THE SUBSIDIARY GUARANTORS NAMED HEREIN,

AND

WELLS FARGO BANK, NATIONAL ASSOCIATION,

as Trustee

SEVENTEENTH SUPPLEMENTAL INDENTURE

Dated as of December 3, 2015

to

Indenture

Dated as of November 2, 2010

4.5 % Senior Notes due 2023

THIS SEVENTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of December 3, 2015, 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 November 2, 2010, as supplemented by the Tenth Supplemental Indenture dated as of January 10, 2013 creating the Issuers’ 4.5% Senior Notes due 2023 (the “Notes”) and as further amended and supplemented in relation to the Notes (the “Indenture”);

WHEREAS, $1,000,000,000 aggregate principal amount of the Notes is currently outstanding;

WHEREAS, Section 10.02 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 an exchange offer for the 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 10.02 of the Indenture;

WHEREAS, the Issuers have been soliciting consents to this Supplemental Indenture upon the terms and subject to the conditions set forth in the Offering Memorandum and Consent Solicitation Statement (herein so called) of MPLX LP and the Company dated November 19, 2015 and the related Letter of Transmittal and Consent (which together, including any amendments, modifications or supplements thereto, govern the “Consent Solicitation” for the Notes); and

WHEREAS, (1) the Issuers have 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 10.06 of the Indenture and (3) the Issuers and the Subsidiary Guarantors have satisfied all other conditions required under Article X 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:

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ARTICLE I

AMENDMENTS TO INDENTURE AND NOTES

Section 1.1 Amendments to Articles 4, 5, 6 and 7. 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 4.09 (Offer to Purchase by Application of Net Proceeds);
Section 5.06 (Change of Control);
Section 5.07 (Asset Sales);
Section 5.08 ( Restricted Payments);
Section 5.09 (Incurrence of Indebtedness and Issuance of Disqualified Equity);
Section 5.11 (Dividend and Other Payment Restrictions Affecting Subsidiaries);
Section 5.12 (Transactions with Affiliates);
Section 5.13 (Additional Subsidiary Guarantees);
Section 5.15 (Business Activities of MarkWest Finance);
Section 5.16 (Sale and Leaseback Transactions);
Section 5.17 (Reports);

Clause (a)(iv) of Section 6.01 (Merger, Consolidation or Sale of Assets); and
Clauses (d) — (h) of Section 7.01 (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 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.

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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 closing of the Consent Solicitation and the related Exchange Offer (as defined in the Offering Memorandum and Consent Solicitation Statement), 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 closing shall not occur. The Company shall notify the Trustee promptly after the occurrence of such closing or promptly after the Company shall determine that such closing 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:

“Effective as of December 3, 2015, certain restrictive covenants of the Company and certain Events of Default have been eliminated or limited, as provided in the Seventeenth Supplemental Indenture, dated as of December 3, 2015. Reference is hereby made to such Seventeenth Supplemental Indenture, copies of which are on file with the Trustee, for a description of the amendments made therein.”

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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]

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

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C.
MARKWEST ENERGY APPALACHIA, L.L.C.
MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY SOUTH TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY WEST 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 MICHIGAN PIPELINE COMPANY, L.L.C.
MARKWEST MOUNTAINEER PIPELINE COMPANY, L.L.C.
MARKWEST NEW MEXICO, L.L.C.
MARKWEST OKLAHOMA GAS COMPANY, 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 LPG PIPELINE, L.L.C.
MARKWEST TEXAS PNG UTILITY, L.L.C.
MARKWEST UTICA OPERATING
COMPANY, L.L.C.
WEST SHORE PROCESSING COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

MARKWEST MCALESTER, L.L.C. MARKWEST BUFFALO CREEK GAS COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Seventeenth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ John Stohlmann
Name:	John Stohlmann
Title:	Vice President

Signature Page to Seventeenth Supplemental Indenture

EX-4.3

Exhibit 4.3

MARKWEST ENERGY PARTNERS, L.P.

AND

MARKWEST ENERGY FINANCE CORPORATION

AND

THE SUBSIDIARY GUARANTORS NAMED HEREIN,

AND

WELLS FARGO BANK, NATIONAL ASSOCIATION,

as Trustee

EIGHTEENTH SUPPLEMENTAL INDENTURE

Dated as of December 3, 2015

to

Indenture

Dated as of November 2, 2010

4.875% Senior Notes due 2024

THIS EIGHTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of December 3, 2015, 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 November 2, 2010, as supplemented by the Thirteenth Supplemental Indenture dated as of November 21, 2014 creating the Issuers’ 4.875% Senior Notes due 2024 (the “Notes”) and as further amended and supplemented in relation to the Notes (the “Indenture”);

WHEREAS, $1,150,000,000 aggregate principal amount of the Notes is currently outstanding;

WHEREAS, Section 10.02 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 an exchange offer for the 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 10.02 of the Indenture;

WHEREAS, the Issuers have been soliciting consents to this Supplemental Indenture upon the terms and subject to the conditions set forth in the Offering Memorandum and Consent Solicitation Statement (herein so called) of MPLX LP and the Company dated November 19, 2015 and the related Letter of Transmittal and Consent (which together, including any amendments, modifications or supplements thereto, govern the “Consent Solicitation” for the Notes); and

WHEREAS, (1) the Issuers have 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 10.06 of the Indenture and (3) the Issuers and the Subsidiary Guarantors have satisfied all other conditions required under Article X 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 4, 5, 6 and 7. 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 4.09 (Offer to Purchase by Application of Net Proceeds);
Section 5.06 (Change of Control);
Section 5.07 (Asset Sales);
Section 5.08 ( Restricted Payments);
Section 5.09 (Incurrence of Indebtedness and Issuance of Disqualified Equity);
Section 5.11 (Dividend and Other Payment Restrictions Affecting Subsidiaries);
Section 5.12 (Transactions with Affiliates);
Section 5.13 (Additional Subsidiary Guarantees);
Section 5.15 (Business Activities of MarkWest Finance);
Section 5.16 (Reports);

Clause (a)(iv) of Section 6.01 (Merger, Consolidation or Sale of Assets); and
Clauses (d) — (h) of Section 7.01 (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 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.

3

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 closing of the Consent Solicitation and the related Exchange Offer (as defined in the Offering Memorandum and Consent Solicitation Statement), 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 closing shall not occur. The Company shall notify the Trustee promptly after the occurrence of such closing or promptly after the Company shall determine that such closing 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:

“Effective as of December 3, 2015, certain restrictive covenants of the Company and certain Events of Default have been eliminated or limited, as provided in the Eighteenth Supplemental Indenture, dated as of December 3, 2015. Reference is hereby made to such Eighteenth 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]

4

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

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C.
MARKWEST ENERGY APPALACHIA, L.L.C.
MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY SOUTH TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY WEST 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 MICHIGAN PIPELINE COMPANY, L.L.C.
MARKWEST MOUNTAINEER PIPELINE COMPANY, L.L.C.
MARKWEST NEW MEXICO, L.L.C.
MARKWEST OKLAHOMA GAS COMPANY, 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 LPG PIPELINE, L.L.C.
MARKWEST TEXAS PNG UTILITY, L.L.C.
MARKWEST UTICA OPERATING
COMPANY, L.L.C.
WEST SHORE PROCESSING COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

MARKWEST MCALESTER, L.L.C. MARKWEST BUFFALO CREEK GAS COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Eighteenth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ John Stohlmann
Name:	John Stohlmann
Title:	Vice President

Signature Page to Eighteenth Supplemental Indenture

EX-4.4

Exhibit 4.4

MARKWEST ENERGY PARTNERS, L.P.

AND

MARKWEST ENERGY FINANCE CORPORATION

AND

THE SUBSIDIARY GUARANTORS NAMED HEREIN,

AND

WELLS FARGO BANK, NATIONAL ASSOCIATION,

as Trustee

NINETEENTH SUPPLEMENTAL INDENTURE

Dated as of December 3, 2015

to

Indenture

Dated as of November 2, 2010

4.875% Senior Notes due 2025

THIS NINETEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of December 3, 2015, 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 November 2, 2010, as supplemented by the Fifteenth Supplemental Indenture dated as of June 2, 2015 creating the Issuers’ 4.875% Senior Notes due 2025 (the “Notes”) as further amended and supplemented in relation to the Notes (the “Indenture”);

WHEREAS, $1,200,000,000 aggregate principal amount of the Notes is currently outstanding;

WHEREAS, Section 10.02 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 an exchange offer for the 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 10.02 of the Indenture;

WHEREAS, the Issuers have been soliciting consents to this Supplemental Indenture upon the terms and subject to the conditions set forth in the Offering Memorandum and Consent Solicitation Statement (herein so called) of MPLX LP and the Company dated November 19, 2015 and the related Letter of Transmittal and Consent (which together, including any amendments, modifications or supplements thereto, govern the “Consent Solicitation” for the Notes); and

WHEREAS, (1) the Issuers have 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 10.06 of the Indenture and (3) the Issuers and the Subsidiary Guarantors have satisfied all other conditions required under Article X 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 4, 5, 6 and 7. 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 4.09 (Offer to Purchase by Application of Net Proceeds);
Section 5.06 (Change of Control);
Section 5.07 (Asset Sales);
Section 5.08 ( Restricted Payments);
Section 5.09 (Incurrence of Indebtedness and Issuance of Disqualified Equity);
Section 5.11 (Dividend and Other Payment Restrictions Affecting Subsidiaries);
Section 5.12 (Transactions with Affiliates);
Section 5.13 (Additional Subsidiary Guarantees);
Section 5.15 (Business Activities of MarkWest Finance);
Section 5.16 (Reports);

Clause (a)(iv) of Section 6.01 (Merger, Consolidation or Sale of Assets); and
Clauses (d) — (h) of Section 7.01 (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 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.

3

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 closing of the Consent Solicitation and the related Exchange Offer (as defined in the Offering Memorandum and Consent Solicitation Statement), 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 closing shall not occur. The Company shall notify the Trustee promptly after the occurrence of such closing or promptly after the Company shall determine that such closing 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:

“Effective as of December 3, 2015, certain restrictive covenants of the Company and certain Events of Default have been eliminated or limited, as provided in the Nineteenth Supplemental Indenture, dated as of December 3, 2015. Reference is hereby made to such Nineteenth 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]

4

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

MARKWEST ENERGY FINANCE CORPORATION
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY PARTNERS, L.P.
	By:	MarkWest Energy GP, L.L.C.,
		its General Partner
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST HYDROCARBON, INC.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
MARKWEST ENERGY GP, L.L.C.
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

MASON PIPELINE LIMITED LIABILITY COMPANY
	By:	MarkWest Hydrocarbon, Inc.,
		its Sole Member
By:	/s/ Nancy Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer
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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

MARKWEST BLACKHAWK, L.L.C.
MARKWEST ENERGY APPALACHIA, L.L.C.
MARKWEST ENERGY EAST TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY SOUTH TEXAS GAS COMPANY, L.L.C.
MARKWEST ENERGY WEST 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 MICHIGAN PIPELINE COMPANY, L.L.C.
MARKWEST MOUNTAINEER PIPELINE COMPANY, L.L.C.
MARKWEST NEW MEXICO, L.L.C.
MARKWEST OKLAHOMA GAS COMPANY, 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 LPG PIPELINE, L.L.C.
MARKWEST TEXAS PNG UTILITY, L.L.C.
MARKWEST UTICA OPERATING
COMPANY, L.L.C.
WEST SHORE PROCESSING COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

MARKWEST MCALESTER, L.L.C. MARKWEST BUFFALO CREEK GAS COMPANY, 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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

MARKWEST RANGER PIPELINE COMPANY, L.L.C
	By:	MarkWest Energy Appalachia, L.L.C.,
		its Sole Member
	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 Buese
Name:	Nancy Buese
Title:	Executive Vice President and Chief Financial Officer

Signature Page to Nineteenth Supplemental Indenture

WELLS FARGO BANK, NATIONAL ASSOCIATION, AS TRUSTEE
By:	/s/ John Stohlmann
Name:	John Stohlmann
Title:	Vice President

Signature Page to Nineteenth Supplemental Indenture

EX-99.1

Exhibit 99.1

MPLX LP and MarkWest Energy Partners, L.P. Announce Successful Early Note Exchange Tender Period

FINDLAY, Ohio, and DENVER, Dec. 4, 2015 — MPLX LP (NYSE: MPLX) and MarkWest Energy Partners, L.P. (NYSE: MWE) (MarkWest) today announced that, in connection with the previously announced offers to exchange (the “Exchange Offers”) any and all of the $4.1 billion in aggregate principal amount of outstanding senior notes issued by MarkWest and MarkWest Energy Finance Corporation (the “Existing MarkWest Notes”) for (1) new senior notes issued by MPLX (the “New MPLX Notes”) and (2) cash, and related consent solicitations (the “Consent Solicitations”) to adopt certain amendments to the indentures governing the Existing MarkWest Notes (the “Indenture Amendments”), MarkWest has received the requisite number of consents to adopt the Indenture Amendments with respect to each of the four outstanding series of Existing MarkWest Notes that are subject to the Exchange Offers and Consent Solicitations. MarkWest intends to promptly enter into supplemental indentures with the trustee for the Existing MarkWest Notes (the “Supplemental Indentures”) to effect the Indenture Amendments.

MPLX also announced that the previous deadline for eligible holders to tender their Existing MarkWest Notes (and thereby give their consents to the Indenture Amendments) and be eligible to receive the New MPLX Notes in the same principal amount as the Existing MarkWest Notes tendered therefor plus a consent payment of $1.00 per $1,000 principal amount of Existing MarkWest Notes tendered (the “Total Exchange Consideration”) has been extended to 12:01 a.m., New York City time, on Dec. 18, 2015 (as extended, the “Exchange Consideration Deadline”). Currently, this is the same time and date as the Expiration Date (as defined below) for the Exchange Offers and Consent Solicitations.

If the Expiration Date is extended and the Exchange Consideration Deadline is not further extended, eligible holders who validly tender their Existing MarkWest Notes after the Exchange Consideration Deadline but before the Expiration Date will be eligible to receive, subject to the terms and conditions set forth in the Offering Memorandum and Consent Solicitation Statement, New MPLX Notes in a principal amount equal to $970 plus a consent payment of $1.00 per $1,000 principal amount of Existing MarkWest Notes tendered therefor, and will not be entitled to the Total Exchange Consideration.

Withdrawal rights for the Exchange Offers and Consent Solicitations have expired as of Dec. 3, 2015 (the “Withdrawal Deadline”). Because the Withdrawal Deadline is not being extended, holders may not withdraw Existing MarkWest Notes, or revoke consents, previously tendered or tendered after the date of this press release, except as may be required by law.

As of the Withdrawal Deadline, the following principal amounts of each series of Existing MarkWest Notes have been validly tendered and not validly withdrawn (and consents thereby validly given and not validly revoked):

Title of Series/CUSIP Number of Existing	Aggregate Principal Amount		Existing MarkWest Notes Tendered at Withdrawal Deadline
MarkWest Notes	Outstanding		Principal Amount		Percentage
5.5% Senior Notes due 2023 / 570506 AQ8	$	750,000,000	$	693,704,000	92.49	%
4.5% Senior Notes due 2023 / 570506 AR6	$	1,000,000,000	$	982,455,000	98.25	%
4.875% Senior Notes due 2024 / 570506 AS4	$	1,150,000,000	$	1,146,345,000	99.68	%
4.875% Senior Notes due 2025 / 570506 AT2	$	1,200,000,000	$	1,179,195,000	98.27	%

The Exchange Offers and Consent Solicitations are being made pursuant to the terms and subject to the conditions set forth in the Offering Memorandum and Consent Solicitation Statement, dated Nov. 19, 2015 (the “Offering Memorandum and Consent Solicitation Statement”), and related Letter of Transmittal and Consent. Except as described in this press release with respect to the extension of the Exchange Consideration Deadline, the terms of the Exchange Offers and Consent Solicitations remain as set forth in the Offering Memorandum and Consent Solicitation Statement and related Letter of Transmittal and Consent.

The Exchange Offers and Consent Solicitations are conditioned upon, and the Supplemental Indentures will only become operative upon, the closing of the acquisition of MarkWest by MPLX pursuant to the Agreement and Plan of Merger, dated as of July 11, 2015, as amended as of Nov. 10, 2015 and as further amended as of Nov. 16, 2015 (the “Merger Agreement”), by and among MPLX, MPLX GP LLC, the general partner of MPLX, Sapphire Holdco LLC, a wholly owned subsidiary of MPLX, for certain limited purposes, Marathon Petroleum Corporation, and MarkWest, pursuant to which MarkWest has agreed to become a wholly-owned subsidiary of MPLX. On Dec. 1, 2015, the MarkWest unitholders approved the Merger Agreement and the transactions contemplated by the Merger Agreement are expected to close on Dec. 4, 2015.

The Exchange Offers and Consent Solicitations will expire at 12:01 a.m., New York City time, on Dec. 18, 2015, unless such date is extended (the “Expiration Date”). MPLX currently expects settlement of the Exchange Offers to occur on Dec. 21, 2015, unless the Expiration Date is extended. MPLX and MarkWest reserve the right to terminate, withdraw, amend or extend the Exchange Offers and Consent Solicitations in their discretion.

Documents relating to the Exchange Offers and Consent Solicitations will only be distributed to eligible holders of Existing MarkWest Notes who complete and return an eligibility form confirming that they are either a “qualified institutional buyer” under Rule 144A or not a “U.S. person” and outside the United States under Regulation S for purposes of applicable securities laws. Except as amended by this press release, the complete terms and conditions of the Exchange Offers and Consent Solicitations are described in the Offering Memorandum and Consent Solicitation Statement and related Letter of Transmittal, copies of which may be obtained by contacting Global Bondholder Services Corporation, the exchange agent and information agent in connection with the Exchange Offers and Consent Solicitations, at (866) 924-2200 (U.S. toll-free) or (212) 430-3774 (banks and brokers). The eligibility form is available electronically at: http://gbsc-usa.com/eligibility/mplx.

This press release does not constitute an offer to sell or purchase, or a solicitation of an offer to sell or purchase, or the solicitation of tenders or consents with respect to, any security. No offer, solicitation, purchase or sale will be made in any jurisdiction in which such an offer, solicitation, or sale would be unlawful. The Exchange Offers and Consent Solicitations are being made solely pursuant to the Offering Memorandum and Consent Solicitation Statement and related Letter of Transmittal, as amended by this press release, and only to such persons and in such jurisdictions as is permitted under applicable law.

The New MPLX Notes have not been and will not be registered under the Securities Act of 1933 or any state securities laws. Therefore, the New MPLX Notes may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements of the Securities Act of 1933 and any applicable state securities laws.

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About MPLX LP

MPLX is a fee-based, growth-oriented master limited partnership formed in 2012 by Marathon Petroleum Corporation to own, operate, develop and acquire pipelines and other midstream assets related to the transportation and storage of crude oil, refined products and other hydrocarbon-based products. Headquartered in Findlay, Ohio, MPLX’s assets consist of a 99.5 percent equity interest in a network of common carrier crude oil and products pipeline assets located in the Midwest and Gulf Coast regions of the United States and a 100 percent interest in a butane storage cavern located in West Virginia with approximately 1 million barrels of natural gas liquids storage capacity.

About MarkWest Energy Partners

MarkWest Energy Partners, L.P. is a master limited partnership that owns and operates midstream service businesses. MarkWest has a leading presence in many natural gas resource plays including the Marcellus Shale, Utica Shale, Huron/Berea Shale, Haynesville Shale, Woodford Shale and Granite Wash formation.

MPLX Investor Relations Contacts:
Geri Ewing (419) 421-2071

Teresa Homan (419) 421-2965

MPLX Media Contacts:
Chuck Rice (419) 421-2521

Jamal Kheiry (419) 421-3312

MarkWest Investor Relations and Media Contact:
Joshua Hallenbeck (866) 858-0482

This press release contains forward-looking statements within the meaning of federal securities laws regarding MPLX LP (“MPLX”), Marathon Petroleum Corporation (“MPC”), and MarkWest Energy Partners, L.P. (“MWE”). These forward-looking statements relate to, among other things, expectations, estimates and projections concerning the business and operations of MPLX, MPC, and MWE. You can identify forward-looking statements by words such as “anticipate,” “believe,” “estimate,” “objective,” “expect,” “forecast,” “guidance,” “imply,” “plan,” “project,” “potential,” “could,” “may,” “should,” “would,” “will” or other similar expressions that convey the uncertainty of future events or outcomes. Such forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and other factors, some of which are beyond the companies’ control and are difficult to predict. In addition to other factors described herein that could cause MPLX’s or MWE’s actual results to differ materially from those implied in these forward-looking statements, negative capital market conditions, including a persistence or increase of the current yield on common units, which is higher than historical yields, could adversely affect MPLX’s ability to meet its distribution growth guidance, particularly with respect to the later years of such guidance. Factors that could cause MPLX’s or MWE’s actual results to differ materially from those implied in the forward-looking statements include: the ability to satisfy conditions to the closing of the transaction contemplated by the merger agreement; risk that the synergies from the MPLX/MWE transaction may not be fully realized or may take longer to realize than expected; disruption from the MPLX/MWE transaction making it more difficult to maintain relationships with customers, employees or suppliers; risks relating to any unforeseen liabilities of MWE or MPLX, as applicable; the adequacy of MPLX’s and MWE’s respective capital resources and liquidity, including, but not limited to, availability of sufficient cash flow to pay distributions, and the ability to successfully execute their business plans and implement their growth strategies; the timing and extent of changes in commodity prices and demand for crude oil, refined products, feedstocks or other hydrocarbon-based products; volatility in and/or degradation of market and industry conditions; completion of pipeline capacity by competitors; disruptions due to equipment interruption or failure, including electrical shortages and power grid failures; the suspension, reduction or termination of MPC’s obligations under MPLX’s commercial agreements; each company’s ability to successfully implement its growth plan, whether through organic growth or acquisitions; modifications to earnings and distribution growth objectives; federal and state environmental, economic, health and safety, energy and other policies and regulations; changes to MPLX’s capital budget; other risk factors inherent to MPLX or MWE’s industry; and the factors set forth under the heading “Risk Factors” in MPLX’s Annual Report on Form 10-K for the year ended Dec. 31, 2014, filed with the

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Securities and Exchange Commission (SEC); and the factors set forth under the heading “Risk Factors” in MWE’s Annual Report on Form 10-K for the year ended Dec. 31, 2014, and Quarterly Report on Form 10-Q for the quarter ended Sept. 30, 2015, filed with the SEC. These risks, as well as other risks associated with MPLX, MWE and the proposed transaction, are also more fully discussed in the joint proxy statement and prospectus included in the registration statement on Form S-4 filed by MPLX and declared effective by the SEC on Oct. 29, 2015, as supplemented. Factors that could cause MPC’s actual results to differ materially from those implied in the forward-looking statements include: risks described above relating to the MPLX/MWE proposed merger; changes to the expected construction costs and timing of pipeline projects; volatility in and/or degradation of market and industry conditions; the availability and pricing of crude oil and other feedstocks; slower growth in domestic and Canadian crude supply; an easing or lifting of the U.S. crude oil export ban; completion of pipeline capacity to areas outside the U.S. Midwest; consumer demand for refined products; transportation logistics; the reliability of processing units and other equipment; MPC’s ability to successfully implement growth opportunities; modifications to MPLX earnings and distribution growth objectives; federal and state environmental, economic, health and safety, energy and other policies and regulations; other risk factors inherent to MPC’s industry; and the factors set forth under the heading “Risk Factors” in MPC’s Annual Report on Form 10-K for the year ended Dec. 31, 2014, filed with SEC. In addition, the forward-looking statements included herein could be affected by general domestic and international economic and political conditions. Unpredictable or unknown factors not discussed here, in MPLX’s Form 10-K, in MPC’s Form 10-K, or in MWE’s Form 10-K and Form 10-Qs could also have material adverse effects on forward-looking statements. Copies of MPLX’s Form 10-K are available on the SEC website, MPLX’s website at http://ir.mplx.com or by contacting MPLX’s Investor Relations office. Copies of MPC’s Form 10-K are available on the SEC website, MPC’s website at http://ir.marathonpetroleum.com or by contacting MPC’s Investor Relations office. Copies of MWE’s Form 10-K and Form 10-Qs are available on the SEC website, MWE’s website at http://investor.markwest.com or by contacting MWE’s Investor Relations office.

Additional Information and Where to Find It

In connection with the proposed acquisition, MPLX and MWE have filed relevant materials with the SEC, including MPLX’s registration statement on Form S-4 that includes a definitive joint proxy statement and a prospectus declared effective by the SEC on Oct. 29, 2015 and a supplement to the proxy statement/prospectus filed on Nov. 17, 2015. Investors and security holders are urged to read all relevant documents filed with the SEC, including the definitive joint proxy statement and prospectus, because they contain important information about the proposed transaction. Investors and security holders are able to obtain the documents free of charge at the SEC’s website, http://www.sec.gov, or for free from MPLX LP at its website, http://ir.mplx.com, or in writing at 200 E. Hardin Street, Findlay, Ohio 45840, Attention: Corporate Secretary, or for free from MWE by contacting Investor Relations by phone at 1-(866) 858-0482 or by email at investorrelations@markwest.com.

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