Exhibit 2.1

Execution Version

CONTRIBUTION AGREEMENT

by and among

ANADARKO UINTAH MIDSTREAM, LLC
WESTERN GAS RESOURCES, INC.
WGR HOLDINGS, LLC
WGR ASSET HOLDING COMPANY LLC
WESTERN GAS HOLDINGS, LLC
WES GP, INC.

as Contributing Parties

and

WESTERN GAS PARTNERS, LP
WESTERN GAS HOLDINGS, LLC
WESTERN GAS OPERATING, LLC
WGR OPERATING, LP

as Recipient Parties

and, for certain limited purposes,
ANADARKO PETROLEUM CORPORATION

Covering the Contribution of

a 51% membership interest in Chipeta Processing LLC;
the 15-mile, 8” AUM NGL pipeline; and
certain other related rights and assets

Dated as of July 10, 2009

TABLE OF CONTENTS

Disclosure Schedules

Exhibits

CONTRIBUTION AGREEMENT

     THIS CONTRIBUTION AGREEMENT, dated as of July 10, 2009 (the “ Agreement ”), is made and entered into by and among Western Gas Resources, Inc., a Delaware corporation (“ WGR ”), WGR Asset Holding Company LLC, a Delaware limited liability company (“ WGRAH ”), Anadarko Uintah Midstream, LLC, a Delaware limited liability company (“ AUM ”), WGR Holdings, LLC, a Delaware limited liability company (“ WGR Holdings ”), Western Gas Holdings, LLC, a Delaware limited liability company (the “ General Partner ”), WES GP, Inc. (“ WES GP ” and, together with the General Partner, WGR, WGRAH, WGR Holdings and AUM, the “ Contributing Parties ”), and Western Gas Partners, LP, a Delaware limited partnership (the “ Partnership ”), Western Gas Operating, LLC, a Delaware limited liability company (“ Western Gas Operating ”), and WGR Operating, LP, a Delaware limited partnership (the “ Operating Partnership ”, and, together with the Partnership, the General Partner and Western Gas Operating, the “ Recipient Parties ”). The Contributing Parties and Recipient Parties are sometimes referred to in this Agreement each as a “ Party ” and collectively as the “ Parties .” In addition, Anadarko Petroleum Corporation, a Delaware corporation (“ Anadarko ”), is a party to this Agreement for the limited purposes set forth in Article II , Article IV , Section 6.6 , Article VIII and Article IX , and is a “Party” under this Agreement solely to that extent.

RECITALS

     WHEREAS, WGR owns all of the equity interests in WGRAH and WGR Holdings, each of which is a disregarded entity for U.S. federal income tax purposes;

     WHEREAS, WGRAH owns all of the equity interests in AUM;

     WHEREAS, WGR Holdings owns 99% of the equity interests in the General Partner, which is a partnership for U.S. federal income tax purposes;

     WHEREAS, WGR Holdings owns all of the equity interests in WES GP, which is a corporation for federal income tax purposes;

     WHEREAS, WES GP owns 1% of the equity interests in the General Partner;

     WHEREAS, WGR Holdings is a limited partner of the Partnership;

     WHEREAS, the General Partner is the sole general partner of the Partnership;

     WHEREAS, the Partnership owns all of the equity interests in Western Gas Operating, which is a disregarded entity for U.S. federal income tax purposes;

     WHEREAS, the Partnership is the sole limited partner and Western Gas Operating is the sole general partner of the Operating Partnership;

     WHEREAS, AUM owns the AUM NGL Line (defined herein) and the related System Assets (defined herein);

     WHEREAS, AUM will acquire the Stagecoach Extension (defined herein) and the related System Assets (defined herein) prior to Closing;

     WHEREAS, AUM also owns the Chipeta Interest (defined herein);

     WHEREAS, AUM desires to distribute the System Assets and the Chipeta Interest to WGRAH and WGRAH desires to acquire the same;

     WHEREAS, WGRAH desires to distribute the System Assets and the Chipeta Interest to WGR and WGR desires to acquire the same;

     WHEREAS, WGR desires to contribute the System Assets and the Chipeta Interest to WGR Holdings and WGR Holdings desires to acquire the same;

     WHEREAS, WGR Holdings desires to contribute an undivided interest in the System Assets and the Chipeta Interest to WES GP, and WES GP desires to acquire such undivided interest;

     WHEREAS, WES GP desires to contribute such undivided interest in the System Assets and the Chipeta Interest to the General Partner, and the General Partner desires to acquire such undivided interest;

     WHEREAS, WGR Holdings desires to contribute an undivided interest in the System Assets and the Chipeta Interest to the General Partner, and the General Partner desires to acquire such undivided interest;

     WHEREAS WGR Holdings and the General Partner desire to contribute all of the undivided interests in the System Assets and the Chipeta Interest to the Partnership for the consideration described herein, and the Partnership desires to acquire such undivided interests for such consideration;

     WHEREAS, the Partnership desires to contribute an undivided interest in the System Assets and the Chipeta Interest to Western Gas Operating, and Western Gas Operating desires to acquire such undivided interest;

     WHEREAS, the Partnership and Western Gas Operating desire to transfer all of the undivided interests in the System Assets and the Chipeta Interest to the Operating Partnership and the Operating Partnership desires to acquire such undivided interests; and

     WHEREAS, in order to avoid multiple conveyances of the System Assets and the Chipeta Interest, each of the Parties entitled to receive an interest in the System Assets and the Chipeta Interest agrees that AUM will be instructed to convey such interest to any Party to which it is required to make such a conveyance, with the result that AUM will execute and deliver a document to convey legal title to the System Assets and the Chipeta Interest directly to the Operating Partnership.

     NOW, THEREFORE, in consideration of the premises and mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties agree as follows:

ARTICLE I
DEFINITIONS AND RULES OF CONSTRUCTION

     Section 1.1 Definitions .

     “ Accounting Time ” has the meaning set forth in Section 3.4(a) .

     “ Affiliate ” means, with respect to any Person, any other Person that, directly or indirectly, Controls, is Controlled by or is under common Control with, such specified Person through one or more intermediaries or otherwise; provided , however , that (i) with respect to each of the Anadarko Entities and the Contributing Parties, the term “Affiliate” shall exclude the Partnership Entities, (ii) with respect to each of the Partnership Entities and the Recipient Parties, the term “Affiliate” shall exclude the Anadarko Entities, and (iii) Chipeta shall be deemed to be an Affiliate of the Anadarko Entities before the Closing Date and an Affiliate of the Partnership Entities on and after the Closing Date.

     “ Aggregate Consideration ” has the meaning set forth in Section 9.8(a) .

     “ Agreement ” has the meaning set forth in the preamble.

     “ Anadarko ” has the meaning set forth in the preamble.

     “ Anadarko Entities ” means Anadarko and any other Person Controlled by Anadarko other than the Partnership Entities.

     “ Anadarko Indemnified Parties ” has the meaning set forth in Section 9.2 .

     “ Ancillary Documents ” means, collectively, the Recipient Party Ancillary Documents and the Contributing Party Ancillary Documents.

     “ Annual Financial Statements ” has the meaning set forth in Section 4.15 .

     “ AUM ” has the meaning set forth in the preamble.

     “ AUM NGL Line ” means the approximately 15-mile, 8-inch NGL pipeline (including all appurtenances thereto) connecting the Chipeta Plant to the pipeline known as the “Mid-America Pipeline,” which NGL pipeline is more specifically described on Exhibit B .

     “ Business Day ” means any day that is not a Saturday, Sunday or legal holiday in the State of Texas or a federal holiday in the United States.

     “ Cash Consideration ” means (i) $101,450,500 minus (ii) an amount equal to the aggregate amount of all distributions (if any) made by Chipeta to AUM with respect to the Chipeta Interest (but not the Remaining Interest) between the date of this Agreement and the

Closing Date, except to the extent that such distributions were regular quarterly distributions required by Section 4.2 of the Chipeta LLC Agreement for quarters ended prior to the Effective Time.

     “ Chipeta ” means Chipeta Processing LLC, a Delaware limited liability company.

     “ Chipeta Assets ” means the Chipeta Plant and the other assets owned, held, used or held for use by Chipeta, which other assets are more specifically described on Exhibit D .

     “ Chipeta Asset Required Consents ” means any consent, approval, authorization or permit of, or filing with or notification to, any Person which was required to be obtained, made or complied with for or in connection with any sale, assignment or transfer to Chipeta of any Chipeta Asset or any Chipeta Surface Contract (or any interest in any of them), and such required consent, approval, authorization, permit, filing or notificiation has not been obtained, made or complied with prior to Closing.

     “ Chipeta LLC Agreement ” means the limited liability company agreement of Chipeta, dated May 22, 2008, as such agreement is amended and in effect on the date of this Agreement.

     “ Chipeta Contracts ” means all contracts, agreements, instruments, undertakings or commitments (including intercompany contracts, agreements, instruments, undertakings or commitments), written or oral, by which Chipeta or any of its properties or assets are bound, or that relate to or are otherwise applicable to Chipeta or the Chipeta Assets (including exchange agreements, transportation or gathering agreements, construction agreements, operating agreements, environmental compliance agreements, processing agreements, work orders, purchase orders, service agreements, rental agreements, compression agreements, utility services agreements, non-disturbance agreements for the benefit of the Chipeta, fractionation agreements, and agreements for the sale and purchase of oil, gas, casinghead gas or other Hydrocarbons or processing agreements to the extent applicable to Chipeta or any of its properties or assets).

     “ Chipeta Interest ” means a 51% membership interest in Chipeta.

     “ Chipeta Interest Contribution Agreement ” means a conveyance, substantially in the form attached hereto as Exhibit F , reflecting the contribution of the Chipeta Interest to the Operating Partnership.

     “ Chipeta Permits ” has the meaning set forth in Section 4.11(c).

     “ Chipeta Plant ” means the Chipeta natural gas processing plant (including all appurtenances thereto), which plant is more specifically described on Exhibit A .

     “ Chipeta Surface Contracts ” means all easements, Chipeta Permits, licenses, servitudes, rights-of-way, surface leases, fee interests in real property and other surface rights appurtenant to, and used or held for use in connection with Chipeta or the Chipeta Assets, including those identified on Schedule 4.6(d) .

     “ CIG ” means Colorado Interstate Gas Company.

     “ CIG Purchase Agreement ” means that certain Purchase and Sale Agreement dated November 21, 2008 between CIG and Chipeta.

     “ Closing ” has the meaning set forth in Section 3.1 .

     “ Closing Date ” has the meaning set forth in Section 3.1 .

     “ Code ” means the Internal Revenue Code of 1986, as amended and as interpreted by the applicable Treasury Regulations thereunder.

     “ Consent Decree ” has the meaning set forth in Section 9.3 .

     “ Contracts ” has the meaning set forth in Section 2.1(b) .

     “ Contributed Assets ” has the meaning set forth in Section 2.7(a) .

     “ Contributing Party Ancillary Documents ” means each agreement, document, instrument or certificate to be delivered by any Contributing Party, or any Affiliate thereof, at the Closing pursuant to Section 3.2 and each other document or contract entered into by any Contributing Party, or any Affiliate thereof, in connection with this Agreement or the Closing.

     “ Contributing Parties ” has the meaning set forth in the preamble.

     “ Contributing Party Closing Certificate ” has the meaning set forth in Section 7.2(c) .

     “ Control ” means, where used with respect to any Person, the possession, directly or indirectly, of the power to direct or cause the direction of the management and policies of such Person, whether through the ownership of voting securities, by contract or otherwise, and the terms “ Controlling ” and “ Controlled ” have correlative meanings.

     “ Deductible ” has the meaning set forth in Section 9.8(a) .

     “ Effective Time ” has the meaning set forth in Section 3.1 .

     “ Environmental Activity ” shall mean any investigation, study, assessment, evaluation, sampling, testing, monitoring, containment, removal, disposal, closure, corrective action, remediation (regardless of whether active or passive), natural attenuation, restoration, bioremediation, response, repair, corrective measure, cleanup, pollution control or abatement that is required or necessary under any applicable Environmental Law, including institutional or engineering controls or participation in a governmental voluntary cleanup program to conduct voluntary investigatory and remedial actions for the clean-up, removal or remediation of Hazardous Substances that exceed actionable levels established pursuant to Environmental Laws, or participation in a supplemental environmental project in partial or whole mitigation of a fine or penalty.

     “ Environmental Laws ” means all federal, state, and local laws, statutes, rules, regulations, orders, judgments, ordinances, codes, injunctions, decrees, Environmental Permits and other legally enforceable requirements and rules of common law relating to (i) pollution or

protection of the environment or natural resources, (ii) any Release or threatened Release of, or any exposure of any Person or property to, any Hazardous Substances or (iii) the generation, manufacture, processing, distribution, use, treatment, storage, transport, disposal or handling of any Hazardous Substances; including the federal Comprehensive Environmental Response, Compensation and Liability Act, the Superfund Amendments and Reauthorization Act, the Resource Conservation and Recovery Act, the Clean Air Act, the Clean Water Act, the Safe Drinking Water Act, the Toxic Substances Control Act, the Oil Pollution Act of 1990, the Federal Hazardous Materials Transportation Law, the Occupational Safety and Health Act, the Marine Mammal Protection Act, the Endangered Species Act, the National Environmental Policy Act and other environmental conservation and protection laws, each as amended through the Closing Date.

     “ Environmental Permit ” means any permit, approval, identification number, license, registration, certification, consent, exemption, variance or other authorization required under or issued pursuant to any applicable Environmental Law.

     “ Equipment ” has the meaning set forth in Section 2.1(d) .

     “ Equity Interest ” means any capital stock, partnership interest, membership interest or other unit of equity security, equity ownership or voting security (including any security convertible into or exchangeable or exercisable for any of the same).

     “ Excluded Assets ” has the meaning set forth in Section 2.2 .

     “ Final Settlement Statement ” has the meaning set forth in Section 2.6(b) .

     “ Financial Statements ” has the meaning set forth in Section 4.15 .

     “ GAAP ” means generally accepted accounting principles in the United States, consistently applied.

     “ General Partner ” has the meaning set forth in the preamble.

     “ Governmental Entity ” means any Federal, state, local, municipal or foreign court or governmental agency, authority or instrumentality or regulatory body having jurisdiction.

     “ GP Consideration ” means 7,172 general partner units of the Partnership.

     “ Hazardous Substance ” means (i) any substance that is designated, defined or classified under any Environmental Law as a hazardous waste, solid waste, hazardous material, pollutant, contaminant or toxic or hazardous substance, or terms of similar meaning, or that is otherwise regulated under any Environmental Law, including any hazardous substance as defined under the Comprehensive Environmental Response, Compensation, and Liability Act, as amended, (ii) oil as defined in the Oil Pollution Act of 1990, as amended, including oil, gasoline, natural gas, fuel oil, motor oil, waste oil, diesel fuel, jet fuel and other refined petroleum hydrocarbons and petroleum products and (iii) radioactive materials, asbestos containing materials or polychlorinated biphenyls.

     “ Hydrocarbons ” means oil, gas, condensate and other gaseous and liquid hydrocarbons or any combination thereof and sulphur extracted from hydrocarbons.

     “ Indemnified Party ” means any Person entitled to indemnification in accordance with Article IX .

     “ Indemnifying Party ” means any Person from whom indemnification is required in accordance with Article IX .

     “ Indemnity Claim ” has the meaning set forth in Section 9.4 .

     “ Independent Accountants ” has the meaning set forth in Section 2.6(c) .

     “ Interim Financial Statements ” has the meaning set forth in Section 4.15 .

     “ Knowledge ” and any variations thereof or words to the same effect means: (i) with respect to the Contributing Parties, the actual knowledge of: (a) the officers of the Contributing Parties and their respective Affiliates, (b) the employees of Contributing Parties who have responsibility for the System Assets and who have the title of Midstream General Manager or Midstream Commercial Development Regional Manager and (c) the employees of Contributing Parties who have responsibility for Chipeta and who have the title of Midstream General Manager or Midstream Commercial Development Regional Manager; and (ii) with respect to the Recipient Parties, the actual knowledge of the officers of Recipient Parties and their respective Affiliates.

     “ Laws ” means all statutes, laws, rules, regulations, Orders, ordinances, writs, injunctions, judgments and decrees of all Governmental Entities.

     “ Lien ” means any lien, security interest, mortgage, pledge, charge, encumbrance or right of others.

     “ Losses ” means any losses, damages, liabilities, claims, demands, causes of action, judgments, settlements, fines, penalties, sanctions, costs and expenses (including court costs and reasonable attorney’s and experts’ fees) of any and every kind or character.

     “ Material Adverse Effect ” means any effect that is material and adverse to the ownership, operation, value, properties, assets, liabilities, financial condition, results of operations, or business (as currently operated) of (a) Chipeta, the Chipeta Assets or the Chipeta Interest or (b) the Systems or the assets related thereto, or the Contributing Parties’ interest therein; provided , however , that “Material Adverse Effect” shall not include (i) any effect resulting from the announcement of entering into this Agreement or of the transactions contemplated by this Agreement; (ii) any effect resulting from changes in general market, economic or financial conditions or any outbreak of hostilities or war, (iii) any effect that affects the Hydrocarbon exploration, production, development, processing, gathering and/or transportation industry generally (including changes in commodity prices or general market prices in the Hydrocarbon exploration, production, development, processing, gathering and/or transportation industry generally) unless such effect disproportionately affects Chipeta, the

Chipeta Plant, the Chipeta Interest or the Systems, as applicable, relative to such industry, and (iv) any effect resulting from a change in Laws.

     “ NORM ” means naturally occurring radioactive material.

     “ Omnibus Agreement ” means the Omnibus Agreement dated as of May 14, 2008 among the Partnership, the General Partner and Anadarko, as amended through the date of this Agreement.

     “ Omnibus Agreement Amendment ” means an instrument substantially in the form set forth on Exhibit I .

     “ Operating Costs ” means all invoices, costs, expenses, disbursements and payables (as determined in accordance with GAAP consistent with past practices) attributable to the operation (but not the ownership) of the System Assets in the ordinary course of business and regularly invoiced to the Contributing Parties. For clarity, Operating Costs do not include, without limitation, all invoices, costs, expenses, disbursements, payables or Losses directly or indirectly arising out of, resulting from or attributable to: (i) actual or claimed personal injury, illness or death; property damage; environmental damage or contamination; negligence, misconduct or failure to operate properly; other torts; private rights of action given under any Law; violation of any Law; or breach or violation of contract, agreement or duty; (ii) obligations to abandon, dismantle, remediate or remove pipelines or facilities; (iii) calamity, natural disaster, casualty, fire, explosion, weather or condemnation; (iv) claims, investigations, administrative proceedings, arbitration or litigation directly or indirectly arising out of, resulting from or attributable to any of the foregoing; (v) any claims for any of the foregoing or for indemnification, contribution, reimbursement or similar matters with respect to invoices, costs, expenses, disbursements, payables or Losses of the type described in clauses (i) through (iv), whether such claims are made pursuant to contract or otherwise; (vi) matters similar to those described in clauses (i) through (v); and (vii) other matters outside the ordinary course of business or related to the ownership of the System Assets.

     “ Operating Partnership ” has the meaning set forth in the preamble.

     “ Order ” means any order, writ, injunction, decree, ruling, compliance or consent order or decree, settlement agreement, schedule and similar binding legal agreement issued by or entered into with a Governmental Entity.

     “ Partnership ” has the meaning set forth in the preamble.

     “ Partnership Agreement Amendment ” means an instrument substantially in the form set forth on Exhibit H .

     “ Partnership Agreement ” means the First Amended and Restated Agreement of Limited Partnership of the Partnership, dated as of May 14, 2008, as such agreement is amended and in effect on the date of this Agreement.

     “ Partnership Debt ” has the meaning set forth in Section 2.5 .

     “ Partnership Entities ” means the General Partner and each member of the Partnership Group.

     “ Partnership Group ” means the Partnership and its Subsidiaries treated as a single consolidated entity.

     “ Partnership Indemnified Parties ” has the meaning set forth in Section 9.3 .

     “ Party ” and “ Parties ” have the meanings set forth in the preamble.

     “ Permits ” means all permits, licenses, variances, exemptions, Orders, franchises, consents, registrations, exemptions, authorizations, permissions and approvals of all Governmental Entities necessary for the lawful ownership, lease and operation of the System Assets.

     “ Permitted Liens ” means (i) liens for Taxes, impositions, assessments, fees, rents or other governmental charges levied or assessed or imposed not yet delinquent or being contested in good faith by appropriate proceedings, provided appropriate reserves have been established with respect to such contest, (ii) statutory liens (including materialmen’s, warehousemen’s, mechanics’, repairmen’s, landlord’s, and other similar liens) arising in the ordinary course of business securing payments not yet delinquent or being contested in good faith by appropriate proceedings, and (iii) utility easements, restrictive covenants and defects, imperfections or irregularities of title that do not and could not reasonably be expected to interfere materially with the ordinary conduct of the business of the System Assets or Chipeta.

     “ Person ” means any individual, firm, corporation, partnership (general or limited), limited liability company, trust, joint venture, Governmental Entity or other entity.

     “ Post Closing Consents ” means (i) any consent, approval or permit of, or filing with or notice to, any Governmental Entity, railroad company or public utility which has issued or granted any permit, license, right of way, lease or other authorizations permitting any part of any pipeline included in the System Assets to cross or be placed on land owned or controlled by such Governmental Entity, railroad company or public utility and (ii) any consent, approval or permit of, or filing with or notice to, any Governmental Entity or other third party with respect to any System Assets that, in the case of both clause (i) and (ii), is customarily obtained or made after closing in connection with transactions similar in nature to the transactions contemplated hereby.

     “ Preference Right ” means any right or agreement that enables any Person to purchase or acquire any System Asset, the Chipeta Interest or any properties or assets of Chipeta (or any interest in or portion of any of them) as a result of or in connection with (i) the sale, assignment or other transfer of any System Asset, the Chipeta Interest or any properties or assets of Chipeta (or any interest in or portion of any of them) or (ii) the execution or delivery of this Agreement or the consummation or performance of this Agreement or the transactions contemplated hereby.

     “ Preliminary Settlement Statement ” has the meaning set forth in Section 2.6(a) .

     “ Recipient Party Ancillary Documents ” means each agreement, document, instrument or certificate to be delivered by any Recipient Party, or any Affiliate thereof, at the Closing

pursuant to Section 3.3 and each other document or contract entered into by any Recipient Party, or any Affiliate thereof, in connection with this Agreement or the Closing.

     “ Recipient Parties ” has the meaning set forth in the preamble.

     “ Recipient Party Closing Certificate ” has the meaning set forth in Section 7.3(b) .

     “ Records ” has the meaning set forth in Section 2.1(i) .

     “ Release ” means any depositing, spilling, leaking, pumping, pouring, placing, emitting, discarding, abandoning, emptying, discharging, migrating, injecting, escaping, leaching, dumping or disposing into the environment.

     “ Remaining Interest ” means the 24% membership interest in Chipeta owned by AUM other than the Chipeta Interest.

     “ Securities Act ” means the Securities Act of 1933.

     “ Settlement Notice ” has the meaning set forth in Section 2.6(c) .

     “ Services and Secondment Agreement ” means the Services and Secondment Agreement dated as of May 14, 2008 by and between the General Partner and Anadarko, as such agreement is amended and in effect on the date of this Agreement.

     “ Special Committee ” has the meaning set forth in the Partnership Agreement.

     “ Stagecoach Agreement ” means the Interconnect Agreement dated July 21, 2008 between AUM and Questar Gas Management Company.

     “ Stagecoach Extension ” means the approximately 1.9-mile, 6-inch pipeline extension (including all appurtenances thereto) connecting the Chipeta Plant to the plant generally known as the “Stagecoach plant”, which pipeline extension is more specifically described on Exhibit C .

     “ Subsidiary ” means, with respect to any Person, (i) a corporation of which more than 50% of the voting power of shares entitled (without regard to the occurrence of any contingency) to vote in the election of directors or other governing body of such corporation is owned, directly or indirectly, at the date of determination, by such Person, by one or more Subsidiaries of such Person or a combination thereof, (ii) a partnership (whether general or limited) in which more than 50% of the partnership interests (considering all of the partnership interests of the partnership as a single class) is owned, directly or indirectly, at the date of determination, by such Person, by one or more Subsidiaries of such Person, or a combination thereof, or (iii) any other Person (other than a corporation or a partnership) in which such Person, one or more subsidiaries of such Person, or a combination thereof, directly or indirectly, at the date of determination, has (A) at least a majority ownership interest or (B) the power to elect or direct the election of a majority of the directors or other governing body of such Person.

     “ Surface Contracts ” has the meaning set forth in Section 2.1(c) .

     “ System Assets ” has the meaning set forth in Section 2.1 .

     “ System Asset Conveyances ” means instruments substantially in the forms attached hereto as Exhibit G .

     “ System Asset Required Consents ” means any consent, approval, authorization or permit of, or filing with or notification to, any Person which was required to be obtained, made or complied with for or in connection with any sale, assignment or transfer pursuant to this Agreement (or any interest in any of them), and such required consent, approval, authorization, permit, filing or notificiation has not been obtained, made or complied with prior to Closing.

     “ Systems ” means the AUM NGL Line and the Stagecoach Extension.

     “ Tax ” or “ Taxes ” means (a) all taxes, assessments, duties, levies, imposts or other similar charges imposed by a Governmental Entity, including all income, franchise, profits, capital gains, capital stock, transfer, gross receipts, margins, sales, use, transfer, service, occupation, ad valorem, property, excise, severance, windfall profits, premium, stamp, license, payroll, employment, social security, unemployment, disability, environmental (including taxes under Code Section 59A), alternative minimum, add-on, value-added, withholding (including backup withholding) and other taxes, assessments, duties, levies, imposts or other similar charges of any kind whatsoever (whether payable directly or by withholding and whether or not requiring the filing of a Tax Return), and all estimated taxes, deficiency assessments, additions to tax, additional amounts imposed by any Governmental Entity, penalties and interest, (b) any liability for the payment of any amounts of any of the foregoing types as a result of being a member of an affiliated, consolidated, combined or unitary group, or being a party to any agreement or arrangement whereby liability for payment of such amounts was determined or taken into account with reference to the liability of any other Person, and (c) any liability for the payment of any amounts as a result of being a party to any Tax-Sharing Agreement or with respect to the payment of any amounts of any of the foregoing types as a result of any express or implied obligation to indemnify any other Person.

     “ Tax Authority ” means any Governmental Entity having jurisdiction over the assessment, determination, collection or imposition of any Tax.

     “ Tax Returns ” means all reports, returns, statements (including estimated reports, returns or statements) and other similar filings relating to, or required to be filed in connection with, any Taxes.

     “ Tax-Sharing Agreements ” means all existing contracts or arrangements (whether or not written) regarding the sharing, allocation, or payment of Taxes or amounts in lieu of Taxes.

     “ Term Loan Agreement ” means a term loan agreement substantially in the form of Exhibit E

     “ Termination Date ” has the meaning set forth in Section 8.1(a)(ii) .

     “ TPH ” has the meaning set forth in Section 4.23 .

     “ Transfer Requirements ” means any consent, approval, authorization or permit of, or filing with or notification to, any Person which is required to be obtained, made or complied with for or in connection with any sale, assignment or transfer of any System Asset, other than Post Closing Consents, or the Chipeta Inter