Exhibit  10.1


 


UNIT PURCHASE AGREEMENT


 


by and among


 


MARKWEST ENERGY PARTNERS,
L.P.,


 


MARKWEST ENERGY GP, L.L.C.


 


AND


 


THE PURCHASERS PARTY HERETO


 





















 


UNIT PURCHASE AGREEMENT


 


UNIT PURCHASE AGREEMENT, dated as of December 18,
2007 (this “Agreement”), by and among MARKWEST ENERGY PARTNERS, L.P. (“MarkWest”),
MARKWEST ENERGY GP, L.L.C. (“MarkWest GP”) (solely for purposes of Section 6.12)
and each of the purchasers set forth on Schedule 2.02 hereof (each a “Purchaser”
and collectively, the “Purchasers”).


 


In consideration of the mutual covenants and
agreements set forth herein and for good and valuable consideration, the
receipt of which is hereby acknowledged, the parties hereby agree as follows:


 


ARTICLE I

DEFINITIONS


 


Section 1.01           Definitions.  As used in this Agreement, and unless the
context requires a different meaning, the following terms have the meanings
indicated:


 


“Action” against a Person means any lawsuit,
action, proceeding, investigation or complaint before any Governmental
Authority, mediator or arbitrator.


 


“Affiliate” means, with respect to a specified
Person, any other Person, directly or indirectly controlling, controlled by or
under direct or indirect common control with such specified Person.  For purposes of this definition, “control”
(including, with correlative meanings, “controlling,” “controlled by,” and “under
common control with”) means the power to direct or cause the direction of the
management and policies of such Person, directly or indirectly, whether through
the ownership of voting securities, by contract or otherwise.


 


“Agreement” has the meaning set forth in the
introductory paragraph.


 


“Basic Documents” means, collectively, this
Agreement, the Registration Rights Agreement, and any and all other agreements
or instruments executed and delivered to the Purchasers by MarkWest or any
Subsidiary of MarkWest hereunder or thereunder.


 


“Business Day” means any day other than a
Saturday, Sunday, or a legal holiday for commercial banks in New York, New
York.


 


“Closing” shall have the meaning specified in Section 2.02.


 


“Closing Date” shall have the meaning specified
in Section 2.02.


 


“Commission” means the United States Securities
and Exchange Commission.


 


“Common Units” means the common units of
MarkWest.


 


“Confidential Information” means all oral or
written information, documents, records and data that MarkWest or its
Representatives furnishes or otherwise discloses to a Purchaser or any of its
Representatives, together with all copies, extracts, analyses, compilations,
studies, 


 





















 


memoranda, notes or other
documents, records or data (in whatever form maintained, whether documentary,
computer or other electronic storage or otherwise) prepared by any Person that
contain or otherwise reflect or are generated from such information, documents,
records, or data.  The term “Confidential
Information” does not include any information that (a) at the time of
disclosure or thereafter is generally available to the public (other than as a
result of a disclosure by such Purchaser or its Representatives), (b) is
developed by such Purchaser or any of its Representatives, independent of, and
without reliance in whole or in part on, any Confidential Information or any
knowledge of Confidential Information, (c) becomes available to such
Purchaser or its Representatives on a non-confidential basis from a source
other than MarkWest or its Representatives who, insofar as is known to the
recipient after reasonable inquiry, is not prohibited from transmitting the
information to the recipient by a contractual, legal, fiduciary or other
obligation to MarkWest or (d) was available to such Purchaser or its
Representatives on a non-confidential basis prior to its disclosure to such
Purchaser or its Representatives by MarkWest or its Representatives.


 


“Exchange Act” means the Securities Exchange
Act of 1934, as amended from time to time, and the rules and regulations
of the Commission promulgated thereunder.


 


“Form 8-A” shall have the meaning set
forth in Section 3.02(a).


 


“GAAP” means generally accepted accounting principles
in the United States of America in effect from time to time.


 


“Governmental Authority” means, with respect to
a particular Person, the country, state, county, city and political
subdivisions in which such Person or such Person’s Property is located or which
exercises valid jurisdiction over any such Person or such Person’s Property,
and any court, agency, department, commission, board, bureau or instrumentality
of any of them and any monetary authority which exercises valid jurisdiction
over any such Person or such Person’s Property. 
Unless otherwise specified, all references to Governmental Authority
herein with respect to MarkWest means a Governmental Authority having
jurisdiction over MarkWest, its Subsidiaries or any of their respective
Properties.


 


“Hydrocarbon Acquisition” means the
transactions contemplated by the Hydrocarbon Purchase Agreement.


 


“Hydrocarbon Purchase Agreement” means the
Agreement and Plan of Redemption and Merger, dated as of September 5, 2007
by and among MarkWest Hydrocarbon, Inc., MarkWest and MWEP, L.L.C.


 


“Indemnified Party” shall have the meaning
specified in Section 6.02(c).


 


“Indemnifying Party” shall have the meaning
specified in Section 6.02(c).


 


“Knowledge” means the actual knowledge of the
individuals listed on Schedule 1.01 hereto after reasonable
inquiry.


 


“Law” means any federal, state, local or
foreign order, writ, injunction, judgment, settlement, award, decree, statute,
law, rule or regulation.


 


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“Lien” means any lien, encumbrance, security
interest, charge or other interest in Property securing an obligation owed to,
or a claim by, a Person other than the owner of the Property, whether such
interest is based on the common law, statute or contract, and whether such
obligation or claim is fixed or contingent, and including but not limited to
the lien or security interest arising from a mortgage, encumbrance, pledge,
security agreement, conditional sale or trust receipt or a lease, consignment
or bailment for security purposes. For the purpose of this Agreement, a Person
shall be deemed to be the owner of any Property which it has acquired or holds
subject to a conditional sale agreement, or leases under a financing lease or
other arrangement pursuant to which title to the Property has been retained by
or vested in some other Person in a transaction intended to create a financing.


 


“MarkWest” has the meaning set forth in the
introductory paragraph.


 


“MarkWest Financial Statements” means the
financial statement or statements described or referred to in Section 3.03.


 


“MarkWest GP” has the meaning set forth in the
introductory paragraph.


 


“MarkWest Material Adverse Effect” means any
material and adverse effect on (a) the assets, liabilities, financial
condition, business, operations or affairs of MarkWest and its Subsidiaries
taken as a whole measured against those assets, liabilities, financial
condition, business, operations or affairs reflected in the MarkWest SEC
Documents filed with the Commission prior to the date hereof or from the facts
represented or warranted in any Basic Document, or (b) the ability of
MarkWest to fulfill any of its obligations under or consummate any of the
transactions contemplated by the Basic Documents.


 


“MarkWest Related Parties” shall have the
meaning specified in Section 6.02(b).


 


“MarkWest SEC Documents” shall have the meaning
specified in Section 3.03.


 


“Partnership Agreement” means the Second
Amended and Restated Agreement of Limited Partnership of MarkWest, dated as of February 28,
2007.


 


“Partnership Securities” means any class or
series of equity interest in MarkWest (but excluding any options, rights,
warrants and appreciation rights relating to an equity interest in MarkWest),
including without limitation Common Units and Incentive Distribution Rights (as
defined in the Partnership Agreement).


 


“Permits” means, with respect to MarkWest or
any of its Subsidiaries, any licenses, permits, variances, consents,
authorizations, waivers, grants, franchises, concessions, exemptions, orders,
registrations and approvals of Governmental Authorities or other Persons
necessary for the ownership, leasing, operation, occupancy and use of its
Properties and the conduct of its businesses as currently conducted.


 


“Person” means any individual, corporation,
company, voluntary association, partnership, joint venture, trust, limited
liability company, unincorporated organization or government or any agency,
instrumentality or political subdivision thereof, or any other form of entity.


 


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“Property” means any interest in any kind of
property or asset, whether real, personal or mixed, or tangible or intangible.


 


“Purchase Price” means, with respect to a
particular Purchaser, the monetary purchase amount set forth opposite such
Purchaser’s name under the column entitled “Total Purchase Price” on Schedule
2.02 hereto.


 


“Purchased Units” means, with respect to a
particular Purchaser, the number of Common Units set forth opposite such
Purchaser’s name under the column entitled “Units Purchased” set forth on Schedule
2.02 hereto.


 


“Purchaser” and “Purchasers” each has
the meaning set forth in the introductory paragraph.


 


“Purchaser Material Adverse Effect” means, with
respect to a particular Purchaser, any material and adverse effect on (a) the
assets, liabilities, financial condition, business, operations or affairs of
such Purchaser, (b) the ability of such Purchaser to carry out its
business as of the date hereof or to meet its obligations under the Basic Documents
on a timely basis or (c) the ability of such Purchaser to consummate the
transactions under any Basic Document.


 


“Purchaser Related Parties” shall have the
meaning specified in Section 6.02(a).


 


“Registration Rights Agreement” means the
Registration Rights Agreement, to be entered into at the Closing, among
MarkWest and the Purchasers in the form attached hereto as Exhibit A.


 


“Representatives” of any Person means the
officers, directors, employees, agents, counsel, investment bankers and other
representatives of such Person.


 


“Securities Act” means the Securities Act of
1933, as amended from time to time, and the rules and regulations of the
Commission promulgated thereunder.


 


“Short Sales” means, without limitation, all “short
sales” as defined in Rule 200 promulgated under Regulation SHO under the
Exchange Act, whether or not against the box, and forward sale contracts,
options, puts, calls, short sales, “put equivalent positions” (as defined in Rule 16a-1(h) under
the Exchange Act) and similar arrangements, and sales and other transactions
through non-U.S. broker dealers or foreign regulated brokers.


 


“Subsidiary” means, as to any Person, any
corporation or other entity of which: (i) such Person or a Subsidiary of
such Person is a general partner or manager; or (ii) at least a majority
of the outstanding equity interest having by the terms thereof ordinary voting
power to elect a majority of the board of directors or similar governing body
of such corporation or other entity (irrespective of whether or not at the time
any equity interest of any other class or classes of such corporation or other
entity shall have or might have voting power by reason of the happening of any
contingency) is at the time directly or indirectly owned or controlled by such Person
or one or more of its Subsidiaries.


 


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“Tax” means any tax, charge, fee, levy, penalty
or other assessment imposed by any U.S. federal, state, local or foreign taxing
authority, including any excise, property, income, sales, transfer, franchise,
payroll, withholding, social security or other tax, including any interest,
penalties or additions attributable thereto.


 


“Tax Return” means any return, report,
information return, declaration, claim for refund or other document (including
any related or supporting information) supplied or required to be supplied to
any authority with respect to Taxes and including any supplement or amendment
thereof.


 


“Unit Price” shall have the meaning set forth
in Section 2.04.


 


Section 1.02           Accounting
Procedures and Interpretation. 
Unless otherwise specified herein, all accounting terms used herein
shall be interpreted, all determinations with respect to accounting matters
hereunder shall be made, and all MarkWest Financial Statements and certificates
and reports as to financial matters required to be furnished to the Purchasers
hereunder shall be prepared, in accordance with GAAP applied on a consistent
basis during the periods involved (except, in the case of unaudited statements,
as permitted by Form 10-Q promulgated by the Commission) and in compliance
as to form in all material respects with applicable accounting requirements and
with the published rules and regulations of the Commission with respect
thereto.


 


ARTICLE II

AGREEMENT TO SELL AND PURCHASE


 


Section 2.01           Sale
and Purchase.  Subject to the terms
and conditions hereof, at the Closing (as defined in Section 2.02)
MarkWest hereby agrees to issue and sell to each Purchaser, and each Purchaser
hereby agrees to purchase from MarkWest, such Purchaser’s Purchased Units, and
each Purchaser agrees to pay MarkWest such Purchaser’s Purchase Price. The
obligation of each Purchaser hereunder is several and not joint and is
independent of the obligation of each other Purchaser, and the failure of, or
MarkWest’s waiver of, performance by any Purchaser does not excuse performance
by any other Purchaser or MarkWest.


 


Section 2.02           Closing.  Subject to the terms and conditions hereof,
the consummation of the purchase and sale of the Purchased Units hereunder (the
“Closing”) shall take place on December 18, 2007 (such date, the “Closing
Date”) at the offices of Vinson & Elkins, L.L.P., 1001 Fannin
Street, Suite 2500, Houston, Texas 77002. 
Each of the items to be delivered, as set forth in Section 2.03,
shall be delivered by the responsible party on the Closing Date.


 


Section 2.03           Deliveries.


 


(a)           At the Closing, subject to the terms
and conditions hereof, MarkWest will deliver, or cause to be delivered, to each
Purchaser:


 


(i)                    The Purchased Units to be
purchased by such Purchaser by delivery of certificates evidencing such
Purchased Units at the Closing meeting the requirements of the Partnership
Agreement, all free and clear of any Liens, encumbrances or interests of any
other Person;


 


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(ii)                   A certificate of the
Secretary of State of the State of Delaware, dated as of a recent date, that
each of MarkWest, MarkWest GP and MarkWest Energy Operating Company, L.L.C. is
in good standing;


 


(iii)                  An opinion addressed to the
Purchasers from Vinson & Elkins L.L.P., dated as of the Closing Date,
in the form and substance attached hereto as Exhibit C;


 


(iv)                  The Registration Rights
Agreement, which shall have been duly executed by MarkWest.


 


(b)           At the Closing, subject to the terms
and conditions hereof, each Purchaser will deliver, or cause to be delivered to
MarkWest.


 


(i)                    The Registration Rights
Agreement, which shall have been duly executed by each such Purchaser; and


 


(ii)                   Such Purchaser’s Purchase Price
by wire transfer of immediately available funds to an account designated by
MarkWest in writing prior to the Closing.


 


Section 2.04           Consideration.  The amount per Common Units each Purchaser
will pay to MarkWest to purchase the Common Units comprising the Purchased
Units shall be $31.50 per Common Unit (the “Unit Price”).


 


Section 2.05           Independent
Nature of Purchasers’ Obligations and Rights.  The obligations
of each Purchaser under any Basic Document are several and not joint with the
obligations of any other Purchaser, and no Purchaser shall be responsible in
any way for the performance of the obligations of any other Purchaser under any
Basic Document.  Nothing contained herein
or in any Basic Document, and no action taken by any Purchaser pursuant thereto,
shall be deemed to constitute the Purchasers as a partnership, an association,
a joint venture or any other kind of entity, or create a presumption that the
Purchasers are in any way acting in concert or as a group with respect to such
obligations or the transactions contemplated by the Basic Document.  Each Purchaser shall be entitled to
independently protect and enforce its rights, including without limitation, the
rights arising out of this Agreement or out of the other Basic Documents, and
it shall not be necessary for any other Purchaser to be joined as an additional
party in any proceeding for such purpose. 
Each Purchaser has been represented by its own separate legal counsel in
their review and negotiation of the Basic Documents.   MarkWest has elected to provide all
Purchasers with the same material terms and Basic Documents for the convenience
of MarkWest and not because it was required or requested to do so by the
Purchasers.


 


Section 2.06           Lock-up.


 


(a)           MarkWest agrees that from and after Closing,
other than (i) in connection with the Hydrocarbon Acquisition or (ii) pursuant
to MarkWest’s Long-Term Incentive Plan and MarkWest’s other equity compensation
plans, as described in MarkWest’s Annual Report on Form 10-K for the
period ended December 31, 2006, it will not sell, 


 


6





















 


nor will it permit any of
its Affiliates to offer, sell, contract to sell, pledge or otherwise dispose
of, or enter into any transaction which is designed to, or might reasonably be
expected to, result in the disposition of any Common Units prior to the date
which is 90 days from the Closing Date.


 


(b)           Each Purchaser agrees that from and
after Closing it will not offer, sell, contract to sell, pledge or otherwise
dispose of, or enter into any transaction which is designed to, or might
reasonably be expected to, result in the disposition of any of the Purchased
Units prior to the date which is 90 days from the Closing Date; provided,
however, that any Purchaser may (i) pledge its Purchased Units in
connection with a bona fide margin account or other loan or financing
arrangement secured by such Purchaser’s Purchased Units or (ii) enter into
a cash settled derivative, total return swap or similar transaction, in each
case, with respect to the Purchased Units purchased by it.


 


ARTICLE III

REPRESENTATIONS AND WARRANTIES RELATED TO MARKWEST


 


MarkWest represents and warrants to each Purchaser as
follows:


 


Section 3.01           Corporate
Existence.  MarkWest: (a) is a
limited partnership duly organized, legally existing and in good standing under
the laws of the State of Delaware; and (b) has all requisite power and
authority, and has all governmental licenses, authorizations, consents and
approvals necessary, to own, lease, use and operate its Properties and carry on
its business as its business is now being conducted, except where the failure
to obtain such licenses, authorizations, consents and approvals would not be
reasonably likely to have a MarkWest Material Adverse Effect.  Each of MarkWest’s Subsidiaries that is a
corporation is a corporation duly incorporated, validly existing and in good
standing under the laws of the State or other jurisdiction of its incorporation
and has all requisite power and authority, and has all governmental licenses,
authorizations, consents and approvals necessary, to own, lease, use or operate
its respective Properties and carry on its business as now being conducted,
except where the failure to obtain such licenses, authorizations, consents and
approvals would not be reasonably likely to have a MarkWest Material Adverse
Effect.  Each Subsidiary of MarkWest that
is not a corporation has been duly formed, is validly existing and in good
standing under the laws of the State or other jurisdiction of its formation and
has all requisite power and authority, and has all governmental licenses,
authorizations, consents and approvals necessary, to own, lease, use or operate
its respective Properties and carry on its business as now being conducted,
except where the failure to obtain such licenses, authorizations, consents and
approvals would not be reasonably likely to have a MarkWest Material Adverse
Effect.  None of MarkWest or any of its
Subsidiaries are in default in the performance, observance or fulfillment of
any provision of, in the case of MarkWest, the Partnership Agreement or its
Certificate of Limited Partnership or, in the case of any Subsidiary of
MarkWest, its respective certificate of incorporation, bylaws or other similar
organizational documents.  Each of
MarkWest and its Subsidiaries is duly qualified or licensed and in good
standing as a foreign corporation or other entity, and is authorized to do
business, in each jurisdiction in which the ownership or leasing of its
respective Properties or the character of its respective operations makes such
qualification necessary, except where the failure to obtain such qualification,
license, authorization or good standing would not be reasonably likely to have
a MarkWest Material Adverse Effect.


 


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Section 3.02           Capitalization
and Valid Issuance of Purchased Units.


 


(a)           As of the date hereof, the issued and
outstanding limited partner interests of MarkWest consist of 36,500,445 Common
Units.  The only issued and outstanding general partner
interests of MarkWest are the interests of the General Partner described and as
defined in the Partnership Agreement.  All outstanding
Common Units and the limited partner interests represented thereby have been
duly authorized and validly issued in accordance with the Partnership Agreement
and are fully paid (to the extent required under the Partnership Agreement) and
nonassessable (except as such nonassessability may be affected by matters
described under the caption “The Partnership Agreement-Limited Liability” in
MarkWest’s registration statement on Form S-1 (No. 333-81780) which
is incorporated by reference into the Partnership’s Registration Statement on Form 8-A
(File No. 001-31239) (the “Form 8-A”)).


 


(b)           Other than MarkWest’s Long-Term
Incentive Plan and MarkWest’s other equity compensation plans, as described in
MarkWest’s Annual Report on Form 10-K for the period ended December 31,
2006, MarkWest has no equity compensation plans that contemplate the issuance
of Common Units (or securities convertible into or exchangeable for Common
Units).  No indebtedness having the right
to vote (or convertible into or exchangeable for securities having the right to
vote) on any matters on which MarkWest unitholders may vote is issued or outstanding.  Except as set forth in the first sentence of
this Section 3.02(b), as are contained in the Partnership Agreement or as
contemplated by the Hydrocarbon Purchase Agreement and disclosed in the joint
proxy statement/prospectus that is part of the Registration Statement on Form S-4
filed with the Commission on November 11, 2007 (File No. 333-147370),
there are no outstanding or authorized (i) options, warrants, preemptive
rights, subscriptions, calls, or other rights, convertible securities, agreements,
claims or commitments of any character obligating MarkWest or any of its
Subsidiaries to issue, transfer or sell any partnership interests or other
equity interest in, MarkWest or any of its Subsidiaries or securities
convertible into or exchangeable for such partnership interests or equity
interests, (ii) obligations of MarkWest or any of its Subsidiaries to
repurchase, redeem or otherwise acquire any partnership interests or equity
interests of MarkWest or any of its Subsidiaries or any such securities or
agreements listed in clause (i) of this sentence or (iii) voting
trusts or similar agreements to which MarkWest or any of its Subsidiaries is a
party with respect to the voting of the equity interests of MarkWest or any of
its Subsidiaries.  At the Closing, except
as described in this Section 3.02(b) and as contemplated by the
Hydrocarbon Purchase Agreement, there will not be any outstanding
subscriptions, options, warrants, calls, preemptive rights, subscriptions, or
other rights, convertible or exchangeable securities, agreements, claims or
commitments of any character by which MarkWest or any of its Subsidiaries will
be bound calling for the purchase or issuance of any partnership interests of
MarkWest or any equity interest of any of its Subsidiaries or securities
convertible into or exchangeable for such partnership or equity interests or
any other such securities or agreements. 
Neither the offering or sale of the Purchased Units nor registration of
the Purchased Units pursuant to the Registration Rights Agreement gives rise to
any rights for or relating to the registration of any Common Units or other
securities of MarkWest.


 


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(c)           (i) All of the issued and
outstanding equity interests of each of MarkWest’s Subsidiaries are owned,
directly or indirectly, by MarkWest free and clear of any Liens (except for
such restrictions as may exist under applicable Law and except for such Liens
as may be imposed under MarkWest’s or MarkWest’s Subsidiaries’ credit
facilities), and all such ownership interests have been duly authorized,
validly issued and are fully paid (to the extent required in the organizational
documents of MarkWest’s Subsidiaries, as applicable) and non-assessable (except
as nonassessability may be affected by Section 6.07 of the Texas Revised
Uniform Limited Partnership Act,  Section 18-607
of the Delaware Limited Liability Company Act, Section 17-607 of the
Delaware Revised Uniform Limited Partnership Act, Section 450.4307 of the
Michigan Limited Liability Company Act, Section 2030 of the Oklahoma
Limited Liability Company Act or the organizational documents of MarkWest’s
Subsidiaries, as applicable) and free of preemptive rights, with no personal
liability attaching to the ownership thereof, and (ii) as of the date
hereof, neither MarkWest nor any of its Subsidiaries owns any shares of capital
stock or other securities of, or interest in, any other Person, or is obligated
to make any capital contribution to or other investment in any other Person.  The material Subsidiaries of MarkWest are set
forth on Schedule 3.02 hereto.


 


(d)           The Common Units being purchased by
the Purchasers hereunder and the limited partner interests represented thereby,
are duly authorized by the Partnership Agreement and, when issued and delivered
to the Purchasers against payment therefor in accordance with the terms of this
Agreement, will be validly issued, fully paid (to the extent required by the
Partnership Agreement) and nonassessable (except as such nonassessability may
be affected by matters described under the caption “The Partnership
Agreement—Limited Liability” in MarkWest’s registration statement on Form S-1
(No. 333-81780) which is incorporated by reference into the Form 8-A)
and will be free of any and all Liens and restrictions on transfer, other than
restrictions on transfer under the Partnership Agreement and under applicable
state and federal securities laws and other than such Liens as are created by
the Purchaser.


 


(e)           The Common Units are listed on the New
York Stock Exchange.


 


(f)            Correct and complete copies of the
Partnership Agreement and MarkWest’s certificate of limited partnership are
attached hereto as Exhibit B.


 


Section 3.03           MarkWest
SEC Documents.  MarkWest has filed
with the Commission all forms, registration statements, reports, schedules and
statements required to be filed by it under the Exchange Act or the Securities
Act (all such documents, collectively “MarkWest SEC Documents”) and,
since October 11, 2005, all such reports and statements have been timely
filed.  The MarkWest SEC Documents,
including, without limitation, any audited or unaudited financial statements
and any notes thereto or schedules included therein (the “MarkWest Financial
Statements”), at the time filed (in the case of registration statements,
solely on the dates of effectiveness) (except to the extent corrected by a
subsequently filed MarkWest SEC Document filed prior to the date hereof) (a) did
not contain any untrue statement of a material fact or omit to state a material
fact required to be stated therein or necessary in order to make the statements
therein, in light of the circumstances under which they were made, not
misleading, (b) 


 


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complied
in all material respects with the applicable requirements of the Exchange Act
and the Securities Act, as the case may be, (c) complied as to form in all
material respects with applicable accounting requirements and with the
published rules and regulations of the Commission with respect thereto, (d) were
prepared in accordance with GAAP applied on a consistent basis during the
periods involved (except as may be indicated in the notes thereto or, in the
case of unaudited statements, as permitted by Form 10-Q of the
Commission), and (e) fairly present (subject in the case of unaudited
statements to normal, recurring and year-end audit adjustments) in all material
respects the consolidated financial position and status of the business of
MarkWest as of the dates thereof and the consolidated results of its operations
and cash flows for the periods then ended. 
PricewaterhouseCoopers LLP, MarkWest’s former public accounting firm, is
an independent public accounting firm with respect to MarkWest and did not
resign and was not dismissed as independent public accountants of MarkWest as a
result of or in connection with any disagreement with MarkWest on a matter of
accounting principles or practices, financial statement disclosure or auditing
scope or procedure.  KPMG LLP, MarkWest’s
former public accounting firm, is an independent public accounting firm with
respect to MarkWest and did not resign and was not dismissed as independent
public accountants of MarkWest as a result of or in connection with any
disagreement with MarkWest on a matter of accounting principles or practices,
financial statement disclosure or auditing scope or procedure.  Deloitte & Touche LLP, MarkWest’s
current public accounting firm, is an independent public accounting firm with respect
to MarkWest and has not resigned or been dismissed as independent public
accountants of MarkWest as a result of or in connection with any disagreement
with MarkWest on a matter of accounting principles or practices, financial
statement disclosure or auditing scope or procedure.  To MarkWest’s Knowledge, the information
(considering all information in the aggregate and excluding all forecasts,
projections and forward looking information), if any, provided by MarkWest to
any Purchaser regarding any potential transaction with MarkWest Hydrocarbon, Inc.
was true and correct in all material respects and did not contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary in order to make the statements therein, in light
of the circumstances under which they were made, not misleading.


 


Section 3.04           No
Material Adverse Change.  Except as
set forth in or contemplated by the MarkWest SEC Documents filed with the
Commission on or prior to the date hereof, since December 31, 2006,
MarkWest and its Subsidiaries have conducted their respective businesses in the
ordinary course, consistent with past practice, and there has been no (a) change,
event, occurrence, effect, fact, circumstance or condition that has had or
would be reasonably likely to have a MarkWest Material Adverse Effect, other
than those occurring as a result of general economic or financial conditions or
other developments that are not unique to MarkWest and its Subsidiaries but
also affect other Persons who participate or are engaged in the lines of
business of which MarkWest and its Subsidiaries participate or are engaged,
except, in each case, to the extent such change, event, occurrence, effect,
fact, circumstance or condition affects MarkWest to a significantly greater
extent than other similarly situated companies generally, (b) acquisition
or disposition of any material asset by MarkWest or any of its Subsidiaries or
any contract or arrangement therefor, otherwise than for fair value in the
ordinary course of business, or (c) material change in MarkWest’s
accounting principles, practices or methods. 
Except as set forth in or contemplated by the MarkWest SEC Documents
filed with the Commission on or prior to the date hereof and MarkWest has
neither issued Partnership Securities (other than under its Long-Term Incentive
Plan and its other equity compensation plans, each as described in the 


 


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MarkWest
SEC Documents filed with the Commission on or prior to the date hereof) nor incurred
material indebtedness since December 31, 2006.


 


Section 3.05           Litigation.  Except as set forth in the MarkWest SEC
Documents filed with the Commission on or prior to the date hereof, there is no
Action pending or, to the knowledge of MarkWest, contemplated or threatened
against or affecting MarkWest, any of its Subsidiaries or any of their
respective officers, directors, properties or assets, which (individually or in
the aggregate) (a) questions the validity of any of the Basic Documents or
the right of MarkWest to enter into any of the Basic Documents or to consummate
the transactions contemplated hereby and thereby or (b) would be
reasonably likely to result in a MarkWest Material Adverse Effect.


 


Section 3.06           No
Breach.  The execution, delivery and
performance by MarkWest of the Basic Documents and all other agreements and
instruments to be executed and delivered by MarkWest pursuant hereto or thereto
or in connection with the transactions contemplated by the Basic Documents or
any such other agreements and instruments, and compliance by MarkWest with the
terms and provisions hereof and thereof and the issuance and sale by MarkWest
of the Purchased Units, do not and will not (a) violate any provision of
any Law or Permit having applicability to MarkWest or any of its Subsidiaries
or any of their respective Properties, (b) conflict with or result in a
violation of any provision of the Certificate of Limited Partnership or other
organizational documents of MarkWest, or the Partnership Agreement, or any
organizational documents of any of MarkWest’s Subsidiaries, (c) require
any consent, approval or notice under or result in a violation or breach of or
constitute (with or without due notice or lapse of time or both) a default (or
give rise to any right of termination, cancellation or acceleration) under any
contract, agreement, instrument, obligation, note, bond, mortgage, license,
loan or credit agreement to which MarkWest or any of its Subsidiaries is a
party or by which MarkWest or any of its Subsidiaries or any of their
respective Properties may be bound, or (d) result in or require the
creation or imposition of any Lien upon or with respect to any of the
Properties now owned or hereafter acquired by MarkWest or any of its
Subsidiaries; with the exception of the conflicts stated in clause (b) of
this Section 3.06, except where such conflict, violation, default, breach,
termination, cancellation, failure to receive consent or approval, or
acceleration with respect to the foregoing provisions of this Section 3.06
would not be, individually or in the aggregate, reasonably likely to have a
MarkWest Material Adverse Effect.


 


Section 3.07           Authority.  MarkWest has all necessary power and
authority to execute, deliver and perform its obligations under the Basic Documents
and the execution, delivery and performance by MarkWest of the Basic Documents;
and the Basic Documents constitute the legal, valid and binding obligations of
MarkWest, enforceable in accordance with their terms, except as such
enforceability may be limited by bankruptcy, insolvency, fraudulent transfer
and similar laws affecting creditors’ rights generally or by general principles
of equity. No approval from the holders of the Common Units is required in
connection with MarkWest’s issuance and sale of the Purchased Units to the
Purchasers.


 


Section 3.08           Approvals.  Except for the approvals required by the
Commission in connection with MarkWest’s obligations under the Registration
Rights Agreement, no authorization, consent, approval, waiver, license,
qualification or written exemption from, nor any filing, declaration,
qualification or registration with, any Governmental Authority or any 


 


11





















 


other
Person is required in connection with the execution, delivery or performance by
MarkWest of any of the Basic Documents, except those already obtained or where
the failure to receive such authorization, consent, approval, waiver, license,
qualification or written exemption from, or to make such filing, declaration,
qualification or registration would not, individually or in the aggregate, be
reasonably likely to have a MarkWest Material Adverse Effect.


 


Section 3.09           MLP
Status.  MarkWest has, for each
taxable year beginning after December 31, 2002 during which MarkWest was
in existence, met the gross income requirements of Section 7704(c)(2) of
the Internal Revenue Code of 1986, as amended.


 


Section 3.10           Offering.  Assuming the accuracy of the representations
and warranties of the Purchasers contained in this Agreement, the sale and
issuance of the Purchased Units to each of the Purchasers pursuant to this
Agreement is exempt from the registration requirements of the Securities Act,
and neither MarkWest nor any authorized agent acting on its behalf has taken or
will take any action hereafter that would cause the loss of such exemptions.


 


Section 3.11           Investment
Company Status.  MarkWest is not an “investment
company” within the meaning of the Investment Company Act of 1940, as amended.


 


Section 3.12           Certain
Fees.  Except for the expense
reimbursement contemplated by Section 6.11, no fees or commissions will be
payable by MarkWest to brokers, finders, or investment bankers with respect to
the sale of any of the Purchased Units or the consummation of the transaction
contemplated by this Agreement.


 


Section 3.13           No
Side Agreements.  Other than
confidentiality agreements entered into with the Purchasers and the
Registration Rights Agreement, there are no other agreements by, among or
between MarkWest or its Affiliates, on the one hand, and any of the Purchasers
or their Affiliates, on the other hand, with respect to the transactions
contemplated hereby nor promises or inducements for future transactions between
or among any of such parties.


 


Section 3.14           Material
Agreements.  MarkWest has provided
the Purchasers (if requested) with correct and complete copies of all material
agreements (as defined in Item 601(b)(10) of Regulation S-K
promulgated by the Commission), including amendments to or other modifications
of pre-existing material agreements, entered into by MarkWest since December 31,
2006.


 


Section 3.15           Form S-3
Eligibility and WKSI Status. 
MarkWest is eligible to register the Purchased Units for resale by the
Purchasers on a registration statement on Form S-3 under the Securities
Act. MarkWest qualifies as a “well-known seasoned issuer” under the Exchange
Act.


 


Section 3.16           Taxes.  MarkWest has filed all Tax Returns required
to be filed.  To the knowledge of
MarkWest, such Tax Returns are true, correct and complete in all material
respects.  MarkWest has paid in full all
Taxes shown to be due on such tax returns. 
MarkWest has not received any written notice of deficiency or assessment
from any taxing authority with respect to liabilities for material Taxes, which
have not been fully paid or finally settled, unless being contested in good
faith through appropriate proceedings and for which adequate reserves are
presented on the MarkWest Financial Statements.


 


12




















 


Section 3.17           Confidential
Information.  To the Knowledge of
MarkWest, none of its employees or executive officers has disclosed material
non-public information (other than the fact that MarkWest was contemplating a
private financing) to any prospective investor who has not entered into a
confidentiality agreement between such prospective investor and MarkWest
relating to such information.


 


ARTICLE IV

REPRESENTATIONS AND WARRANTIES OF EACH PURCHASER


 


Each Purchaser, severally and not jointly, represents
and warrants to MarkWest with respect to itself:


 


Section 4.01           Investment.  The Purchased Units are being acquired for
its own account, not as a nominee or agent, and with no intention of
distributing the Purchased Units or any part thereof, and that such Purchaser
has no present intention of selling or granting any participation in or
otherwise distributing the same in any transaction in violation of the
securities laws of the United States of America or any State, without
prejudice, however, to such Purchaser’s right at all times to sell or otherwise
dispose of all or any part of the Purchased Units under a registration
statement under the Securities Act and applicable state securities laws or
under an exemption from such registration available thereunder (including,
without limitation, if available, Rule 144 promulgated thereunder). If
such Purchaser should in the future decide to dispose of any of the Purchased
Units, such Purchaser understands and agrees (a) that it may do so only (i) in
compliance with the Securities Act and applicable state securities law, as then
in effect, or (ii) in the manner contemplated by any registration
statement pursuant to which such securities are being offered, and (b) that
stop-transfer instructions to that effect will be in effect with respect to
such securities until such time as the Purchased Units become eligible for
resale under Rule 144. 
Notwithstanding the foregoing, a Purchaser may enter into a derivative
transaction or one or more total return swaps with respect to its Purchased
Units with a third party provided that such transaction is exempt from
registration under the Securities Act.


 


Section 4.02           Nature
of Purchaser.  Such Purchaser
represents and warrants to, and covenants and agrees with, MarkWest that, (a) it
is an “accredited investor” within the meaning of Rule 501 of Regulation D
promulgated by the Commission pursuant to the Securities Act and (b) by
reason of its business and financial experience it has such knowledge,
sophistication and experience in making similar investments and in business and
financial matters generally so as to be capable of evaluating the merits and
risks of the prospective investment in the Purchased Units, is able to bear the
economic risk of such investment and, at the present time, would be able to
afford a complete loss of such investment.


 


Section 4.03           Receipt
of Information; Authorization.  Such
Purchaser acknowledges that it has had access to MarkWest’s periodic filings
with the Commission and the joint proxy statement/prospectus that is part of
the Registration Statement on Form S-4 filed with the Commission on November 11,
2007 (File No. 333-147370).


 


Section 4.04           Corporate
Existence.  Such Purchaser, if an
entity: (a) is duly incorporated or formed, legally existing and in good
standing under the laws of its respective jurisdiction of incorporation or
formation; and (b) has all requisite power and authority, and has all 


 


13

















 


governmental
licenses, authorizations, consents and approvals necessary, to own, lease, use
and operate its Properties and carry on its business as its business is now
being conducted, except where the failure to obtain such licenses,
authorizations, consents and approvals would not have or would not reasonably be expected to have a Purchaser Material
Adverse Effect. Each such Purchaser is not in default in the performance,
observance or fulfillment of any provision of its organizational documents,
except where such default would not have or would not be reasonably
likely to have a Purchaser Material Adverse Effect.


 


Section 4.05           No
Breach.  The execution, delivery and
performance by such Purchaser of this Agreement, the Registration Rights
Agreement and all other agreements and instruments to be executed and delivered
by such Purchaser pursuant hereto or thereto or in connection with the
transactions contemplated by this Agreement, the Registration Rights Agreement
or any such other agreements and instruments, and compliance by such Purchaser
with the terms and provisions hereof and thereof, and the purchase of such
Purchaser’s Purchased Units by such Purchaser do not and will not (a) violate
any provision of any Law or permit having applicability to such Purchaser or
any of its Properties, (b) conflict with or result in a violation of any
provision of the organizational documents of such Purchaser, (c) require
any consent or approval under or result in a violation or breach of or
constitute (with or without due notice or lapse of time or both) a default (or
give rise to any right of termination, cancellation or acceleration) under any
contract, agreement, instrument, obligation, note, bond, mortgage, license,
loan or credit agreement to which such Purchaser is a party or by which such
Purchaser or any of its Properties may be bound, or (d) result in or
require the creation or imposition of any Lien upon or with respect to any of
the Properties now owned or hereafter acquired by such Purchaser; with the
exception of the conflicts stated in clause (b) of this Section 4.05,
except where such conflict, violation, default, breach, termination,
cancellation, failure to receive consent or approval, or acceleration with
respect to the foregoing provisions of this Section 4.05 would not,
individually or in the aggregate, be reasonably likely to have a Purchaser
Material Adverse Effect.


 


Section 4.06           Restricted
Securities.  Such Purchaser
understands that the Purchased Units it is purchasing are characterized as “restricted
securities” under the federal securities laws inasmuch as they are being
acquired from MarkWest in a transaction not involving a public offering and
that under such laws and applicable regulations such securities may be re-sold
without registration under the Securities Act only in certain limited circumstances.
In this connection, Purchaser represents that it is knowledgeable with respect
to Rule 144 of the Commission promulgated under the Securities Act.


 


Section 4.07           Certain
Fees.  No fees or commissions will be
payable by such Purchaser to brokers, finders, or investment bankers with
respect to the purchase of any of the Purchased Units or the consummation of
the transaction contemplated by this Agreement.


 


Section 4.08           Legend.  It is understood that the certificates
evidencing the Purchased Units may bear the following legend:  “THIS SECURITY HAS NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE ‘SECURITIES ACT’),
AND MAY NOT BE OFFERED OR SOLD, UNLESS IT HAS BEEN REGISTERED UNDER THE
SECURITIES ACT OR UNLESS AN EXEMPTION FROM REGISTRATION IS AVAILABLE (AND, IN
SUCH CASE, AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE PARTNERSHIP
SHALL HAVE BEEN 


 


14

















 


DELIVERED
TO THE PARTNERSHIP TO THE EFFECT THAT SUCH OFFER OR SALE IS NOT REQUIRED TO BE
REGISTERED UNDER THE SECURITIES ACT).”


 


Section 4.09           No
Side Agreements.  Other than
confidentiality agreements entered into with MarkWest and the Registration
Rights Agreement, there are no other agreements by, among or between such
Purchaser and any of its Affiliates, on the one hand, and any of the other
Purchasers or their Affiliates, on the other hand, with respect to the
transactions contemplated hereby nor promises or inducements for future
transactions between or among any of such parties.


 


Section 4.10           Short
Selling.  Such Purchaser represents
that it has not entered into any Short Sales of the Common Units owned by it
between the time it first began discussions with MarkWest about the
transactions contemplated by this Agreement and the date hereof (it being
understood that the entering into of a total return swap should not be
considered a short sale of Common Units).


 


ARTICLE V

COVENANTS


 


Section 5.01           Certain
Special Allocations of Book and Taxable Income.  To the extent that the Unit Price is less
than the trading price of the Common Units on the New York Stock Exchange as of
the Closing Date, the General Partner intends to specially allocate items of
book and taxable income to the Purchasers so that their capital accounts in
their Units are consistent, on a per-Unit basis, with the capital accounts of
the other holders of Common Units (and thus to assure fungibility of all Common
Units).  Such special allocation will
occur upon the earlier to occur of any taxable period of MarkWest ending upon,
or after, (i) a book-up event or book-down event in accordance with
Treasury Regulation Section 1.704-1(b)(2)(iv)(f) or a sale of all or
substantially all of the assets of MarkWest occurring after the date of the
issuance of the Common Units or (ii) the transfer of the Common Units to a
Person that is not an Affiliate of the holder. 
A Purchaser holding a Common Unit shall be required to provide notice to
the General Partner of the transfer of a Common Unit to a Person that is not an
Affiliate of the Purchaser no later than the last Business Day of the calendar
year during which such transfer occurred, unless by virtue of the application
of clause (i) above, the General Partner has determined that the Common
Units are consistent, on a per-Unit basis, with the capital accounts of the
other holders of Common Units.


 


Section 5.02           Short
Selling Acknowledgement and Agreement. 
Each Purchaser understands and acknowledges, severally and not jointly
with any other Purchaser, that the Commission currently takes the position that
coverage of short sales of securities  “against
the box” prior to the effective date of a registration statement related
thereto is a violation of Section 5 of the Securities Act.  Each Purchaser agrees, severally and not
jointly, that it will not engage in any Short Sales that result in the
disposition of the Purchased Units acquired hereunder by the Purchaser until
such time as the Purchaser may freely sell such Purchased Units pursuant to Rule 144
under the Securities Act (it being understood that the entering into of a total
return swap should not be considered a Short Sale of Purchased Units).  No Purchaser makes any representation,
warranty or covenant hereby that it will not engage in Short Sales that result
in the disposition of securities of MarkWest, other than the Purchased Units,
owned by such 


 


15

















 


Purchaser
or borrowed from a broker after the date MarkWest issues a press release in
respect of this Agreement


 


Section 5.03           Non-Disclosure;
Interim Public Filings.  MarkWest
shall, on or before 8:30 a.m., New York time, on the second Business Day
following execution of this Agreement, issue a press release reasonably
acceptable to the Purchasers disclosing all material terms of the transactions
contemplated hereby and file a Current Report on Form 8-K with the
Commission describing the terms of the transactions contemplated by this
Agreement and the other Basic Documents and including as exhibits to such
Current Report on Form 8-K this Agreement and the Registration Rights
Agreement, in the form required by the Exchange Act.


 


ARTICLE VI

MISCELLANEOUS


 


Section 6.01           Interpretation
and Survival of Provisions.  Article,
Section, Schedule, and Exhibit references are to this Agreement, unless otherwise
specified.  All references to
instruments, documents, contracts, and agreements are references to such
instruments, documents, contracts, and agreements as the same may be amended,
supplemented, and otherwise modified from time to time, unless otherwise
specified.  All references to a party in
this Agreement shall include such party’s successors and permitted
assigns.  The word “including” shall mean
“including but not limited to.”  The
terms “will” and “shall” shall be interpreted to have the same meaning.  Words in the singular form will be construed
to include the plural and vice versa, unless the context otherwise
requires.  The section headings contained
in this Agreement are inserted for convenience only and will not affect in any
way the meaning or interpretation of this Agreement.  Whenever MarkWest has an obligation under the
Basic Documents, the expense of complying with that obligation shall be an
expense of MarkWest unless otherwise specified. Whenever any determination,
consent, or approval is to be made or given by a Purchaser, such action shall
be in such Purchaser’s sole discretion unless otherwise specified in this
Agreement.  If any provision in the Basic
Documents is held to be illegal, invalid, not binding, or unenforceable, such
provision shall be fully severable and the Basic Documents shall be construed
and enforced as if such illegal, invalid, not binding, or unenforceable
provision had never comprised a part of the Basic Documents, and the remaining
provisions shall remain in full force and effect.  The Basic Documents have been reviewed and
negotiated by sophisticated parties with access to legal counsel and shall not
be construed against the drafter.  The
representations and warranties set forth in Sections 3.01, 3.02, 3.06, 3.07,
3.08, 3.12, 3.13, 4.01, 4.02, 4.03, 4.04, 4.05, 4.06, 4.07 and 4.09 hereunder
shall survive the execution and delivery of this Agreement indefinitely, and
the other representations and warranties set forth herein shall survive for a
period of twelve (12) months following the Closing Date regardless of any
investigation made by or on behalf of MarkWest or each of the Purchasers.  The covenants made in this Agreement or any
other Basic Document shall survive the Closing of the transactions described
herein and remain operative and in full force and effect regardless of
acceptance of any of the Purchased Units and payment therefor and repayment or
repurchase thereof.  All indemnification
obligations of MarkWest and the provisions of Section 6.02 shall remain
operative and in full force and effect unless such obligations are expressly
terminated in a writing executed by all the parties to this Agreement
referencing that individual Section, regardless of any purported general
termination of this Agreement.


 


16

















 


Section 6.02           Indemnification,
Costs and Expenses.


 


(a)           Indemnification by MarkWest.  MarkWest agrees to indemnify each Purchaser
and its officers, directors, employees and agents (collectively, the “Purchaser
Related Parties”) from, and hold each of them harmless against any and all
actions, suits, proceedings (including any investigations, litigation or
inquiries), demands, and causes of action, and, in connection therewith, and
promptly upon demand, pay or reimburse each of them for all reasonable costs,
losses, liabilities, damages, or expenses of any kind or nature whatsoever,
including, without limitation, the reasonable fees and disbursements of counsel
and all other reasonable expenses incurred in connection with investigating,
defending or preparing to defend any such matter that may be incurred by them
or asserted against or involve any of them as a result of, arising out of, or
in any way related to (i) any actual or proposed use by MarkWest of the proceeds
of any sale of the Purchased Units or (ii) the breach of any of the
representations, warranties or covenants of MarkWest contained herein, provided
such claim for indemnification relating to a breach of a representation or
warranty is made prior to the expiration of such representation or warranty.


 


(b)           Indemnification by Purchasers.  Each Purchaser agrees, severally and not
jointly, to indemnify MarkWest, MarkWest GP and their officers, directors,
employees and agents (collectively, the “MarkWest Related Parties”)
from, and hold each of them harmless against any and all actions, suits,
proceedings (including any investigations, litigation, or inquiries), demands,
and causes of action, and, in connection therewith, and promptly upon demand,
pay or reimburse each of them for all reasonable costs, losses, liabilities,
damages, or expenses of any kind or nature whatsoever, including, without
limitation, the reasonable fees and disbursements of counsel and all other
reasonable expenses incurred in connection with investigating, defending or
preparing to defend any such matter that may be incurred by them or asserted
against or involve any of them as a result of, arising out of, or in any way
related to the breach of any of the representations, warranties or covenants of
such Purchaser contained herein, provided such claim for indemnification
relating to a breach of the representations and warranties is made prior to the
expiration of such representations and warranties.


 


(c)           Indemnification Procedure.  Promptly after any MarkWest Related Party or
Purchaser Related Party (hereinafter, the “Indemnified Party”) has
received notice of any indemnifiable claim hereunder, or the commencement of
any action or proceeding by a third person, which the Indemnified Party
believes in good faith is an indemnifiable claim under this Agreement, the
Indemnified Party shall give the indemnitor hereunder (the “Indemnifying
Party”) written notice of such claim or the commencement of such action or
proceeding, but failure to so notify the Indemnifying Party will not relieve
the Indemnifying Party from any liability it may have to such Indemnified Party
hereunder except to the extent that the Indemnifying Party is materially
prejudiced by such failure. Such notice shall state the nature and the basis of
such claim to the extent then known.  The
Indemnifying Party shall have the right to defend and settle, at its own
expense and by its own counsel, any such matter as long as the Indemnifying Party
pursues the same diligently and in good faith. If the Indemnifying Party
undertakes to defend or settle, it shall promptly notify the Indemnified Party
of its intention to do so, and the Indemnified 


 


17

















 


Party shall cooperate with
the Indemnifying Party and its counsel in all commercially reasonable respects
in the defense thereof and the settlement thereof. Such cooperation shall
include, but shall not be limited to, furnishing the Indemnifying Party with
any books, records and other information reasonably requested by the
Indemnifying Party and in the Indemnified Party’s possession or control.  Such cooperation of the Indemnified Party
shall be at the cost of the Indemnifying Party. 
After the Indemnifying Party has notified the Indemnified Party of its
intention to undertake to defend or settle any such asserted liability, and for
so long as the Indemnifying Party diligently pursues such defense, the
Indemnifying Party shall not be liable for any additional legal expenses
incurred by the Indemnified Party in connection with any defense or settlement
of such asserted liability; provided, however, that the
Indemnified Party shall be entitled (i) at its expense, to participate in
the defense of such asserted liability and the negotiations of the settlement
thereof and (ii) if (A) the Indemnifying Party has failed to assume
the defense and employ counsel or (B) if the defendants in any such action
include both the Indemnified Party and the Indemnifying Party and counsel to
the Indemnified Party shall have concluded that there may be reasonable
defenses available to the Indemnified Party that are different from or in
addition to those available to the Indemnifying Party or if the interests of
the Indemnified Party reasonably may be deemed to conflict with the interests
of the Indemnifying Party, then the Indemnified Party shall have the right to
select a separate counsel and to assume such legal defense and otherwise to
participate in the defense of such action, with the expenses and fees of such
separate counsel and other expenses related to such participation to be
reimbursed by the Indemnifying Party as incurred.  Notwithstanding any other provision of this
Agreement, the Indemnifying Party shall not settle any indemnified claim
without the consent of the Indemnified Party, unless the settlement thereof
imposes no liability or obligation on, and includes a complete release from
liability of, and does not include any admission of wrongdoing or illegal
conduct by the Indemnified Party.


 


Section 6.03           No
Waiver; Modifications in Writing.


 


(a)           Delay.  No failure or delay on the part of any party
in exercising any right, power, or remedy hereunder shall operate as a waiver
thereof, nor shall any single or partial exercise of any such right, power, or
remedy preclude any other or further exercise thereof or the exercise of any
right, power, or remedy. The remedies provided for herein are cumulative and
are not exclusive of any remedies that may be available to a party at law or in
equity or otherwise.


 


(b)           Specific Waiver.  Except as otherwise provided herein, no
amendment, waiver, consent, modification, or termination of any provision of
this Agreement or any other Basic Document shall be effective unless signed by
each of the parties hereto or thereto affected by such amendment, waiver,
consent, modification, or termination. 
Any amendment, supplement or modification of or to any provision of this
Agreement or any other Basic Document, any waiver of any provision of this Agreement
or any other Basic Document, and any consent to any departure by MarkWest from
the terms of any provision of this Agreement or any other Basic Document shall
be effective only in the specific instance and for the specific purpose for
which made or given. Except where notice is specifically required by this
Agreement, no notice to or demand on MarkWest in 


 


18

















 


any case shall entitle
MarkWest to any other or further notice or demand in similar or other
circumstances.


 


Section 6.04                                Binding Effect;
Assignment.


 


(a)           Binding Effect.  This Agreement shall be binding upon
MarkWest, each Purchaser, and their respective successors and permitted
assigns. Except as expressly provided in this Agreement, this Agreement shall
not be construed so as to confer any right or benefit upon any Person other
than the parties to this Agreement, and their respective successors and
permitted assigns.


 


(b)           Assignment of Purchased Units.  All or any portion of a Purchaser’s Purchased
Units purchased pursuant to this Agreement may be sold, assigned or pledged by
such Purchaser, subject to compliance with applicable securities laws and Section 2.06(b).


 


(c)           Assignment of Rights.  Each Purchaser may assign all or any portion
of its rights and obligations under this Agreement without the consent of
MarkWest (i) to any Affiliate of such Purchaser, (ii) in connection
with a total return swap or similar transaction with respect to the Purchased
Units purchased by such Purchaser or (iii) in connection with a
foreclosure in respect of Purchased Units pledged by a Purchaser in connection
with a bona fide margin account or other loan or financing arrangement, and in
each case the assignee shall be deemed to be a Purchaser hereunder with respect
to such assigned rights or obligations and shall agree in writing to be bound
by the provisions of this Agreement. 
Except as expressly permitted by this Section 6.04(c), such rights
and obligations may not otherwise be transferred except with the prior written
consent of MarkWest (which consent shall not be unreasonably withheld), in
which case the assignee shall be deemed to be a Purchaser hereunder with
respect to such assigned rights or obligations and shall agree in writing to be
bound by the provisions of this Agreement.


 


Section 6.05           Confidentiality.  Notwithstanding anything herein to the
contrary, the confidentiality agreement executed by each Purchaser in favor of
MarkWest shall survive the Closing and each Purchaser shall continue to remain
bound by such confidentiality agreement. 
Disclosure of Confidential Information will not be deemed to be a breach
of this Section 6.05 if such disclosure is made with the consent of
MarkWest or pursuant to a subpoena or order issued by a court of competent
jurisdiction or by a judicial or administrative or legislative body or
committee; provided, however, that upon receipt by a Purchaser of
any subpoena or order covering Confidential Information of MarkWest, such
Purchaser will promptly notify MarkWest of such subpoena or order.


 


Section 6.06           Communications.  All notices and demands provided for
hereunder shall be in writing and shall be given by registered or certified
mail, return receipt requested, telecopy, regular mail, air courier
guaranteeing overnight delivery, electronic mail or personal delivery to the
following addresses:


 


19

















 


(a)                                  If to MarkWest:


 


1515 Arapahoe Street


Tower 2, Suite 700


Denver, CO  80202


Attention:  Nancy K. Buese


Facsimile:  (303) 925-9309


Email:  nbuese@markwest.com


 


with a copy (which shall not constitute
notice) to:


 


Vinson & Elkins L.L.P.


2500 First City Tower


1001 Fannin Street


Houston, Texas 77002


Attention: 
David P. Oelman, Esq.


Facsimile: 
(713) 615-5861


Email: 
doelman@velaw.com


 


(b)                                 If to Magnetar
Spectrum Fund:


 


Magnetar Spectrum Fund


c/o Magnetar Financial LLC


1603 Orrington Avenue, 13th Floor


Evanston, IL 60201


Facsimile:  847-905-5687


 


with a copy (which shall not constitute
notice) to:


 


Baker Botts L.L.P.


98 San Jacinto Boulevard


Suite 1500


Austin, Texas 78701


Attention: 
Laura L. Tyson, Esq.


Facsimile: (512) 322-8377


 


(c)                                  If to Kayne
Anderson Capital Income Partners (QP), LP, Kayne Anderson MLP Fund, LP, Kayne
Anderson Midstream Opportunity Fund, LP, ARBCO II, L.P. or Kayne Anderson
Energy Total Return Fund, Inc.:


 


Kayne
Anderson Capital Advisors, L.P.


Attn:
David Shladovsky, Esq.


1800
Avenue of the Stars, 2nd Floor


Los
Angeles, CA 90067


Facsimile:
(310) 284-6490


 


with a copy (which shall not constitute
notice) to:


 


20

















 


Kayne
Anderson Fund Advisors


Attn:
Kevin McCarthy


717
Texas Avenue, Suite 3100


Houston,
Texas 77002


Facsimile:
(713) 655-7359


 


(d)                                 If to Hartz
Capital Investments, LLC:


 


Hartz Capital Investments, LLC


c/o Hartz Capital, Inc.


Attn:  Noah
Lerner


400 Plaza Drive


Secaucus, NJ 
07094


Facsimile: (201) 866-6387


 


with a copy (which shall not constitute
notice) to:


 


Hartz
Capital Investments, LLC


c/o
Hartz Capital, Inc.


Attn:  Tim Terry


400
Plaza Drive


Secaucus,
NJ  07094


Facsimile: (201)
866-6387


 


(e)                                  If to Tortoise
Energy Capital Corporation:


 


Tortoise Energy Capital Corporation


10801 Mastin Blvd., Suite 222


Overland Park, KS  66210


Attention: Zach Hamel


 


or to such other address as
MarkWest or such Purchaser may designate in writing. All notices and communications
shall be deemed to have been duly given at the time delivered by hand, if
personally delivered; upon actual receipt if sent by registered or certified
mail, return receipt requested, or regular mail, if mailed; when receipt
acknowledged, if sent via facsimile or electronic mail; and upon actual receipt
when delivered by an air courier guaranteeing overnight delivery.


 


Section 6.07           Removal
of Legend.  MarkWest shall promptly
remove the legend described in Section 4.08 from the certificates
evidencing the Purchased Units at the request of a Purchaser submitting to
MarkWest such certificates, together with an opinion of counsel of such
Purchaser and other documentation, if required by MarkWest’s transfer agent, to
the effect that such legend is no longer required under the Securities Act or
applicable state securities Laws, as the case may be; provided that no
opinion of counsel shall be required by MarkWest in the event a Purchaser is
effecting a sale of such Purchased Units pursuant to and in accordance with Rule 144
under the Securities Act or an effective registration statement and (i) the
transfer agent does not require an opinion of counsel or (ii) the
Purchaser provides counsel to MarkWest with such 


 


21

















 


certificates
or other evidence reasonably requested in order for such counsel to render an
opinion to the transfer agent.  All costs
associated with any opinion required by the transfer agent pursuant to any such
removal shall be paid by MarkWest.


 


Section 6.08           Entire
Agreement.  This Agreement, the other
Basic Documents and the other agreements and documents referred to herein are
intended by the parties as a final expression of their agreement and intended
to be a complete and exclusive statement of the agreement and understanding of
the parties hereto in respect of the subject matter contained herein and
therein. There are no restrictions, promises, warranties or undertakings, other
than those set forth or referred to herein or therein with respect to the
rights granted by MarkWest or any of its Affiliates or each of the Purchasers
or any of their Affiliates set forth herein or therein.  This Agreement, the other Basic Documents and
the other agreements and documents referred to herein supersede all prior
agreements and understandings between the parties with respect to such subject
matter.


 


Section 6.09           Governing
Law.  This Agreement will be
construed in accordance with and governed by the laws of the State of Delaware
without regard to principles of conflicts of laws.


 


Section 6.10           Execution
in Counterparts.  This Agreement may
be executed in any number of counterparts and by different parties hereto in
separate counterparts, each of which counterparts, when so executed and
delivered, shall be deemed to be an original and all of which counterparts,
taken together, shall constitute but one and the same Agreement.


 


Section 6.11           Expenses.  MarkWest hereby covenants and agrees to
reimburse Magnetar Spectrum Fund or any of its Affiliates for the reasonable and
documented legal expenses of Baker Botts L.L.P. incurred in connection with the
negotiation, execution, delivery and performance of the Basic Documents and the
transactions contemplated hereby and thereby, up to $40,000.00.  Upon MarkWest’s request, any request for such
reimbursement by Purchasers shall be accompanied by a detailed invoice for such
amount.  If any action at law or equity
is necessary to enforce or interpret the terms of the Basic Documents, the prevailing
party shall be entitled to reasonable attorney’s fees, costs and necessary
disbursements in addition to any other relief to which such party may be
entitled.


 


Section 6.12           Waiver
of Preemptive Right.  Other than the
obligation of MarkWest GP to make contributions to MarkWest as required by Section 5.2
of the Partnership Agreement, MarkWest GP hereby waives (for itself and on
behalf of its Affiliates) its preemptive rights provided under Section 5.9
of the Partnership Agreement with respect to the issuances of Partnership
Securities pursuant to this Agreement.


 


[The remainder of this page is
intentionally left blank.]


 


22
















 


IN WITNESS WHEREOF, the parties hereto execute this
Agreement, effective as of the date first above written.


 


	
  MARKWEST ENERGY
  PARTNERS, L.P.

  
	
   

  	
   

  	
   

  
	
  By:

  	
  MarkWest Energy GP,
  L.L.C., 

  
	
   

  	
  its general partner

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ NANCY K. BUESE

  
	
   

  	
   

  	
  Nancy K. Buese

  
	
   

  	
   

  	
  Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  MARKWEST ENERGY GP,
  L.L.C.

  
	
  (solely for the purpose of
  Section  6.12)

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ NANCY K. BUESE

  
	
   

  	
   

  	
  Nancy K. Buese

  
	
   

  	
   

  	
  Chief Financial Officer

  
				



 

















 


	
  MAGNETAR SPECTRUM FUND

  
	
   

  	
   

  	
   

  
	
  By:

  	
  Magnetar
  Financial LLC,

  
	
   

  	
  its
  investment manager

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ PAUL SMITH

  
	
   

  	
  Name:

  	
  Paul Smith

  
	
   

  	
  Title:

  	
  General Counsel

  
				



 

















 


	
  KAYNE
  ANDERSON MLP FUND, LP

  
	
   

  	
   

  	
   

  	
   

  
	
  By:

  	
  Kayne
  Anderson Capital Advisors, L.P., 

  
	
   

  	
  its
  general partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ DAVID SHLADOVSKY

  
	
   

  	
   

  	
  David
  Shladovsky

  
	
   

  	
   

  	
  General Counsel

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  KAYNE
  ANDERSON CAPITAL INCOME PARTNERS (QP), LP

  
	
   

  	
   

  	
   

  	
   

  
	
  By:

  	
  Kayne
  Anderson Capital Advisors, L.P., 

  
	
   

  	
  its
  general partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ DAVID SHLADOVSKY

  
	
   

  	
   

  	
  David
  Shladovsky

  
	
   

  	
   

  	
  General Counsel

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  KAYNE
  ANDERSON MIDSTREAM OPPORTUNITY FUND, LP

  
	
   

  	
   

  	
   

  	
   

  
	
  By:

  	
  Kayne
  Anderson Capital Advisors, L.P., 

  
	
   

  	
  its
  general partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ DAVID SHLADOVSKY

  
	
   

  	
   

  	
  David
  Shladovsky

  
	
   

  	
   

  	
  General Counsel

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  ARBCO
  II, L.P.

  
	
   

  	
   

  	
   

  	
   

  
	
  By:

  	
  Kayne
  Anderson Capital Advisors, L.P.,

  
	
   

  	
  its
  general partner

  
	
   

  	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ DAVID SHLADOVSKY

  
	
   

  	
   

  	
  David
  Shladovsky

  
	
   

  	
   

  	
  General Counsel

  
					



 

















 


	
  KAYNE ANDERSON ENERGY TOTAL RETURN FUND, INC.

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ JAMES C. BAKER

  
	
   

  	
  James C. Baker

  
	
   

  	
  Vice President

  



 

















 


	
  TORTOISE ENERGY CAPITAL
  CORPORATION

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ DAVID J. SCHULTE

  
	
   

  	
  Name:

  	
  David J. Schulte

  
	
   

  	
  Title:

  	
  Chief Executive Officer

  
				



 

















 


	
  HARTZ
  CAPITAL INVESTMENTS, LLC

  
	
   

  	
   

  	
   

  
	
  By:

  	
  Hartz Capital, Inc.

  
	
   

  	
  its
  manager

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ RONALD J. BANGS

  
	
   

  	
   

  	
  Ronald J. Bangs

  
	
   

  	
  Title:

  	
  Chief Operating Officer

  
				



 

















 


Exhibit A — Form of Registration Rights Agreement


 


[Omitted]


 

















 


Exhibit B — Partnership Agreement and Certificate of Limited
Partnership


 


[Omitted]


 





















 


Exhibit C — Form of Opinion of MarkWest Counsel


 


[Omitted]


 

















 


Schedule 1.01


 


Cory Bromley


Nancy K. Buese


John Mollenkopf


Randy S. Nickerson


Andrew L. Schroeder


Frank M. Semple


 

















 


Schedule 2.02


 


	
  Purchaser

  	
   

  	
  Units Purchased

  	
   

  	
  Total Purchase

  Price

  	
   

  
	
  Magnetar Spectrum Fund

  	
   

  	
  1,904,762

  	
   

  	
  $

  	
  60,000,003.00

  	
   

  
	
  Kayne Anderson Capital
  Income Partners (QP), LP

  	
   

  	
  19,842

  	
   

  	
  625,023.00

  	
   

  
	
  Kayne Anderson MLP Fund,
  LP

  	
   

  	
  109,127

  	
   

  	
  3,437,500.50

  	
   

  
	
  Kayne Anderson Midstream
  Opportunity Fund, LP

  	
   

  	
  19,842

  	
   

  	
  625,023.00

  	
   

  
	
  ARBCO II, L.P.

  	
   

  	
  9,921

  	
   

  	
  312,511.50

  	
   

  
	
  Kayne Anderson Energy
  Total Return Fund, Inc.

  	
   

  	
  158,731

  	
   

  	
  5,000,026.50

  	
   

  
	
  Tortoise Energy Capital
  Corporation

  	
   

  	
  317,461

  	
   

  	
  10,000,021.50

  	
   

  
	
  Hartz Capital Investments,
  LLC

  	
   

  	
  317,461

  	
   

  	
  10,000,021.50

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Total

  	
   

  	
  2,857,147

  	
   

  	
  $

  	
  90,000,130.50

  	
   

  



 

















 


Schedule 3.02


 


MarkWest Energy Appalachia, L.L.C.


 


MarkWest Energy East Texas Gas Company, L.P.


 


MarkWest Energy Operating Company, L.L.C.


 


MarkWest Javelina Pipeline Holding, L.P.


 


MarkWest Javelina Holding
Company, L.P.


 


MarkWest Pinnacle L.P.


 


MarkWest Texas GP, L.L.C.


 


MW Texas Limited, L.L.C.


 


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