Markwest Energy Partners L P Sample Contracts

Markwest Energy Partners L P – MPLX LP and MarkWest Energy Partners, L.P. Announce Successful Early Note Exchange Tender Period (December 4th, 2015)

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 M

Markwest Energy Partners L P – 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 (December 4th, 2015)

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”).

Markwest Energy Partners L P – 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 (December 4th, 2015)

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”).

Markwest Energy Partners L P – 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 (December 4th, 2015)

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”).

Markwest Energy Partners L P – 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 (December 4th, 2015)

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”).

Markwest Energy Partners L P – AMENDMENT NUMBER 2 TO AGREEMENT AND PLAN OF MERGER (November 17th, 2015)

THIS AMENDMENT NUMBER 2 TO AGREEMENT AND PLAN OF MERGER, dated as of November 16, 2015 (this “Amendment”), is made by and among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), solely for purposes of Section 5.15 of the Merger Agreement (defined below), Marathon Petroleum Corporation, a Delaware corporation and the ultimate parent of Parent GP (“MPC”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned Subsidiary of Parent (“Merger Sub” and, with MPC, Parent and Parent GP, the “Parent Entities”).

Markwest Energy Partners L P – VOTING AGREEMENT (November 17th, 2015)

This VOTING AGREEMENT (this “Agreement”), dated as of November 16, 2015, is entered into by and among MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned subsidiary of Parent (“Merger Sub” and, with Parent and Parent GP, the “Parent Entities”), and each of the Persons set forth on Schedule A hereto (each, a “Unitholder”), as investment adviser, manager or general partner on behalf of various record and beneficial owners. All terms used but not otherwise defined in this Agreement shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

Markwest Energy Partners L P – VOTING AGREEMENT (November 17th, 2015)

This VOTING AGREEMENT (this “Agreement”), dated as of November 16, 2015, is entered into by and among MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned subsidiary of Parent (“Merger Sub” and, with Parent and Parent GP, the “Parent Entities”), and each of the Persons set forth on Schedule A hereto (each, a “Unitholder”), as investment adviser, manager or general partner on behalf of various record and beneficial owners. All terms used but not otherwise defined in this Agreement shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

Markwest Energy Partners L P – Investor presentation November 12, 2015 Non-Gaap financial measures / Forward- Looking Statements 2 MarkWest Energy Partners, L.P. is a master limited partnership that owns and operates midstream services related 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 where it provides midstream services to its producer customers. Cautionary Statement Regarding Forward-Looking Statements This communication includes “forward-looking statements.” All s (November 12th, 2015)
Markwest Energy Partners L P – AMENDMENT TO AGREEMENT AND PLAN OF MERGER (November 10th, 2015)

THIS AMENDMENT TO AGREEMENT AND PLAN OF MERGER, dated as of November 10, 2015  (this “Amendment”), is made by and among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), solely for purposes of Section 5.15 of the Merger Agreement (defined below), Marathon Petroleum Corporation, a Delaware corporation and the ultimate parent of Parent GP (“MPC”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned Subsidiary of Parent (“Merger Sub” and, with MPC, Parent and Parent GP, the “Parent Entities”).

Markwest Energy Partners L P – MarkWest Energy Partners, L.P. Contact: Frank Semple, Chairman, President & CEO (November 4th, 2015)

·                  Received the first place ranking for Total Customer Satisfaction and five other categories in EnergyPoint Research’s 2015 Oil & Gas Midstream Services Customer Satisfaction Survey

Markwest Energy Partners L P – MarkWest Energy Partners Announces Filing of Definitive Proxy Statement Special Meeting of Unitholders to be Held on December 1, 2015 (October 30th, 2015)

DENVER—October 30, 2015—MarkWest Energy Partners, L.P. (the “Partnership”) (NYSE: MWE) today announced that it has filed a definitive proxy statement and prospectus with the U.S. Securities and Exchange Commission regarding the pending merger pursuant to which the Partnership would become a wholly owned subsidiary of MPLX LP (“MPLX”) (NYSE: MPLX). A special meeting of the common unitholders has been set to approve the previously announced Agreement and Plan of Merger, dated as of July 11, 2015, by and among the Partnership, MPLX, MPLX GP LLC, the general partner of MPLX, Sapphire Holdco LLC, a wholly owned subsidiary of MPLX, and, for certain limited purposes, Marathon Petroleum Corporation.

Markwest Energy Partners L P – MarkWest Energy Partners, L.P. Contact: Frank Semple, Chairman, President & CEO (August 5th, 2015)

·                  Placed into service 1.0 Bcf/d of new processing capacity, with the addition of Majorsville VI, Houston IV, and Sherwood VI in the Marcellus; and Cadiz III and Seneca IV in the Utica

Markwest Energy Partners L P – FOURTEENTH SUPPLEMENTAL INDENTURE (August 5th, 2015)

This FOURTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of June 3, 2015, is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“Finance Corporation” and, together with the Partnership, the “Issuers”), each of the other parties identified on the signature page hereto (the “Subsidiary Guarantors”) and Wells Fargo Bank, National Association, a national banking association, as trustee (the “Trustee”).

Markwest Energy Partners L P – MPLX and MarkWest Strategic Combination As Revised July 20, 2015 Forward‐Looking Statements This presentation 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 MPC, MPLX and MWE. You can identify forward-looking statements by words such as “anticipate,” “believe,” “commit,” “ imply,” “estimate,” "objective," (July 20th, 2015)
Markwest Energy Partners L P – AGREEMENT AND PLAN OF MERGER Dated as of July 11, 2015 among MPLX LP, MPLX GP LLC, Marathon Petroleum Corporation, Sapphire Holdco LLC, and MarkWest Energy Partners, L.P. (July 13th, 2015)

This AGREEMENT AND PLAN OF MERGER, dated as of July 11, 2015 (this “Agreement”), is by and among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), solely for purposes of Section 5.15, Marathon Petroleum Corporation, a Delaware corporation and the ultimate parent of Parent GP (“MPC”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned Subsidiary of Parent (“Merger Sub” and, with MPC, Parent and Parent GP, the “Parent Entities”).  Certain terms used in this Agreement are defined in Section 8.11.

Markwest Energy Partners L P – MPLX and MarkWest Strategic Combination July 13, 2015 Forward-Looking Statements 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 MPC, MPLX and MWE. You can identify forward-looking statements by words such as “anticipate,” “believe,” “estimate,” "objective," “expect,” “forecast,” "plan," (July 13th, 2015)
Markwest Energy Partners L P – VOTING AGREEMENT (July 13th, 2015)

This VOTING AGREEMENT (this “Agreement”), dated as of July 11, 2015, is entered into by and among MPLX LP, a Delaware limited partnership (“Parent”), MPLX GP LLC, a Delaware limited liability company and the general partner of Parent (“Parent GP”), and Sapphire Holdco LLC, a Delaware limited liability company and a wholly owned subsidiary of Parent (“Merger Sub” and, with Parent and Parent GP, the “Parent Entities”), and each of the Persons set forth on Schedule A hereto (each, a “Unitholder”).  All terms used but not otherwise defined in this Agreement shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

Markwest Energy Partners L P – MARKWEST ENERGY PARTNERS, L.P. MARKWEST ENERGY FINANCE CORPORATION 4.875% Senior Notes due 2025 Underwriting Agreement (June 2nd, 2015)

MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), and MarkWest Energy Finance Corporation, a Delaware corporation (“Finance Corp” and, together with the Partnership, the “Issuers”), propose to issue and sell to the several underwriters listed in Schedule III hereto (the “Underwriters”), for whom you are acting as representative (the “Representative”), $1,200,000,000 aggregate principal amount of their 4.875% Senior Notes due 2025 (the “Notes”).  The Notes will be issued pursuant to the Indenture (the “Base Indenture”) dated as of November 2, 2010 among the Issuers, the Guarantors (as defined below) and Wells Fargo Bank, National Association, as trustee (the “Trustee”), and will be guaranteed on an unsecured senior basis by each of the Guarantors (the “Guarantees” and, together with the Notes, the “Securities”).  The term “Indenture,” as used herein means the Base Indenture, as amended and supplemented by the Fifteenth Supplemental Indenture (the “Fifte

Markwest Energy Partners L P – MarkWest Energy Partners Announces Public Offering of $1.2 Billion of Senior Notes Due 2025 (June 2nd, 2015)

DENVER—May 28, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (together with the Partnership, the “Issuers”) announced today that, subject to market conditions, they intend to commence a public offering (the “offering”) of $1,200,000,000 in aggregate principal amount of senior unsecured notes due 2025 (the “2025 Notes”).

Markwest Energy Partners L P – MARKWEST ENERGY PARTNERS, L.P., MARKWEST ENERGY FINANCE CORPORATION, as Issuers, THE SUBSIDIARIES NAMED HEREIN, as Subsidiary Guarantors and WELLS FARGO BANK, NATIONAL ASSOCIATION, as Trustee (June 2nd, 2015)

THIS FIFTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”) dated as of June 2, 2015 is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), the Subsidiary Guarantors (as defined herein) listed on Schedule A hereto, and Wells Fargo Bank, National Association, a national banking association, as Trustee under the Indenture, dated as of November 2, 2010, among the Issuers, the Subsidiary Guarantors named therein and the Trustee (the “Base Indenture” and, as amended and supplemented by this Supplemental Indenture, in respect of the 4.875% Senior Notes due 2025, the “Indenture”).

Markwest Energy Partners L P – MarkWest Energy Partners Closes Public Offering of $1.2 Billion of 4.875% Senior Notes Due 2025 (June 2nd, 2015)

DENVER—June 2, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (together with the Partnership, the “Issuers”) announced today the closing of a public offering of $1,200,000,000 in aggregate principal amount of 4.875% senior unsecured notes due 2025 (the “2025 Notes”).

Markwest Energy Partners L P – MarkWest Energy Partners Announces Pricing of an Offering of $1.2 Billion of 4.875% Senior Notes Due 2025 (June 2nd, 2015)

DENVER—May 28, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (together with the Partnership, the “Issuers”) announced today that they have priced at 99.026% of par an offering of $1,200,000,000 in aggregate principal amount of 4.875% senior unsecured notes due 2025 (the “2025 Notes”). The offering of the 2025 Notes is expected to settle on June 2, 2015, subject to customary closing conditions.

Markwest Energy Partners L P – EIGHTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT among MARKWEST ENERGY PARTNERS, L.P., as the Borrower, WELLS FARGO BANK, NATIONAL ASSOCIATION, as Administrative Agent, and The Agents and Lenders from Time to Time Parties Thereto, Dated as of May 28, 2015 WELLS FARGO SECURITIES, LLC and RBC CAPITAL MARKETS, as Joint Lead Arrangers and WELLS FARGO SECURITIES, LLC, and RBC CAPITAL MARKETS as Joint Bookrunners (May 28th, 2015)

THIS EIGHTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (herein called the “Amendment”) dated as of May 28, 2015 among MARKWEST ENERGY PARTNERS, L.P., a Delaware limited partnership (“Borrower”), WELLS FARGO BANK, NATIONAL ASSOCIATION, as Administrative Agent, Swingline Lender, and Issuing Bank, the several banks and other financial institutions or entities parties to the Credit Agreement defined below (“Lenders and individually, a “Lender”),

Markwest Energy Partners L P – MarkWest Energy Partners Announces Tender Offers for Its 6.75% Senior Notes due 2020, 6.5% Senior Notes due 2021 and 6.25% Senior Notes due 2022 (May 28th, 2015)

DENVER—May 28, 2015 (BUSINESS WIRE)—MarkWest Energy Partners, L.P. (NYSE: MWE) announced today that it has commenced three concurrent cash tender offers (the “offers”) to purchase any and all of the senior notes listed in the following table at the cash purchase prices shown in the column titled “Consideration per $1,000 of Notes.”

Markwest Energy Partners L P – MarkWest Energy Partners Reports First Quarter Financial Results (May 6th, 2015)

·                  Reported record total gas volumes of 5.4 Bcf/d for the first quarter 2015, an increase of 52 percent from the first quarter 2014. The Partnership is now the second largest gas processor in the U.S.

Markwest Energy Partners L P – MarkWest Energy Partners Closes Public Offering of Additional $650 Million of 4.875% Senior Notes Due 2024 (March 3rd, 2015)

DENVER—March 3, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (“Finance Corp.”) announced today the closing of a public offering of an additional $650 million of 4.875% senior unsecured notes due 2024 (the “Additional Notes”).

Markwest Energy Partners L P – MarkWest Energy Partners Announces Pricing of an Upsized Public Offering of Additional $650 Million of 4.875% Senior Notes Due 2024 (March 3rd, 2015)

DENVER—February 26, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (“Finance Corp.”) announced today that they have priced an upsized public offering of an additional $650 million of their outstanding 4.875% senior unsecured notes due 2024 (the “Additional Notes”). The Additional Notes will be issued at 101.625% of par plus accrued and unpaid interest from November 21, 2014, resulting in a yield to worst of 4.66%. The offering of the Additional Notes is expected to settle on March 3, 2015, subject to customary closing conditions.

Markwest Energy Partners L P – MarkWest Energy Partners Announces Public Offering of Additional $500 Million of 4.875% Senior Notes Due 2024 (March 3rd, 2015)

DENVER—February 26, 2015—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation (“Finance Corp.”) announced today that, subject to market conditions, they intend to commence a public offering of an additional $500 million of 4.875% senior unsecured notes due 2024 (the “Additional Notes”).

Markwest Energy Partners L P – MARKWEST ENERGY PARTNERS, L.P. MARKWEST ENERGY FINANCE CORPORATION 4.875% Senior Notes due 2024 Underwriting Agreement (March 3rd, 2015)
Markwest Energy Partners L P – MarkWest Energy Partners Reports Record 2014 Fourth Quarter and Full-Year Financial Results (February 25th, 2015)

·                  Reported record DCF of $201.0 million for the fourth quarter and $706.4 million for the full-year 2014, and record Adjusted EBITDA of $243.0 million for the fourth quarter and $874.3 million for the full-year 2014. Full-year 2014 DCF and Adjusted EBITDA increased by approximately 46 and 44 percent, respectively from the full-year 2013

Markwest Energy Partners L P – SEVENTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT among MARKWEST ENERGY PARTNERS, L.P., as the Borrower, WELLS FARGO BANK, NATIONAL ASSOCIATION, as Administrative Agent, and The Agents and Lenders from Time to Time Parties Thereto, Dated as of February 3, 2015 WELLS FARGO SECURITIES, LLC and RBC CAPITAL MARKETS, as Joint Lead Arrangers and WELLS FARGO SECURITIES, LLC, and RBC CAPITAL MARKETS as Joint Bookrunners (February 3rd, 2015)

THIS SEVENTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (herein called the “Amendment”) dated as of February 3, 2015 among MARKWEST ENERGY PARTNERS, L.P., a Delaware limited partnership (“Borrower”), WELLS FARGO BANK, NATIONAL ASSOCIATION, as Administrative Agent, Swingline Lender, and Issuing Bank, the several banks and other financial institutions or entities parties to the Credit Agreement defined below (“Lenders and individually, a “Lender”),

Markwest Energy Partners L P – MARKWEST ENERGY PARTNERS, L.P. MARKWEST ENERGY FINANCE CORPORATION 4.875% Senior Notes due 2024 Underwriting Agreement (November 21st, 2014)

MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), and MarkWest Energy Finance Corporation, a Delaware corporation (“Finance Corp” and, together with the Partnership, the “Issuers”), propose to issue and sell to the several underwriters listed in Schedule III hereto (the “Underwriters”), for whom you are acting as representative (the “Representative”), $500,000,000 aggregate principal amount of their 4.875% Senior Notes due 2024 (the “Notes”).  The Notes will be issued pursuant to an Indenture (the “Base Indenture”) dated as of November 2, 2010 among the Issuers, the Guarantors (as defined below) and Wells Fargo Bank, National Association, as trustee (the “Trustee”), and will be guaranteed on an unsecured senior basis by each of the Guarantors (the “Guarantees” and, together with the Notes, the “Securities”).  The term “Indenture,” as used herein includes the Base Indenture and the Thirteenth Supplemental Indenture (the “Thirteenth Supplemental Indentur

Markwest Energy Partners L P – MARKWEST ENERGY PARTNERS, L.P., MARKWEST ENERGY FINANCE CORPORATION, as Issuers, THE SUBSIDIARIES NAMED HEREIN, as Subsidiary Guarantors and WELLS FARGO BANK, NATIONAL ASSOCIATION, as Trustee (November 21st, 2014)

THIS THIRTEENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”) dated as of November 21, 2014 is among MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), MarkWest Energy Finance Corporation, a Delaware corporation (“MarkWest Finance” and, together with the Partnership, the “Issuers”), the Subsidiary Guarantors (as defined herein) listed on Schedule A hereto, and Wells Fargo Bank, National Association, a national banking association, as Trustee under the Indenture, dated as of November 2, 2010, among the Issuers, the Subsidiary Guarantors named therein and the Trustee (the “Base Indenture” and, as amended and supplemented by this Supplemental Indenture, in respect of the 4.875% Senior Notes due 2024, the “Indenture”).

Markwest Energy Partners L P – MarkWest Energy Partners Announces Pricing of an Offering of $500 Million of 4.875% Senior Notes Due 2024 (November 21st, 2014)

DENVER—November 18, 2014—MarkWest Energy Partners, L.P. (NYSE: MWE) (the “Partnership”) and its subsidiary MarkWest Energy Finance Corporation announced today that they have priced at par an offering of $500,000,000 in aggregate principal amount of 4.875% senior unsecured notes due 2024 (the “Notes”). The offering of the Notes is expected to settle on November 21, 2014, subject to customary closing conditions.