Limited Liability Company Agreement Dated June 29, 2006

Exhibit 10.6

LIMITED LIABILITY COMPANY AGREEMENT

of

ATLAS ENERGY OPERATING COMPANY, LLC

THIS LIMITED LIABILITY COMPANY AGREEMENT made as of June 29, 2006 by and between ATLAS ENERGY OPERATING COMPANY, LLC, a Delaware limited liability company (the " Company" ) and ATLAS ENERGY RESOURCES, LLC, a Delaware limited liability company (the " Member" ).

1. FORMATION AND PURPOSE

1.1 Formation . In accordance with the Act, the Member hereby organizes a limited liability company for the purposes hereinafter expressed. 1.2 Purpose . The Company' s purpose shall be to engage in all lawful businesses for which limited liability companies may be organized under the Act. The Company shall have the authority to do all things necessary or advisable in order to accomplish such purposes.

2. MANAGEMENT & MEETINGS

2.1 Management . The management of the business and affairs of the Company shall be vested in the Member who shall have the power to do any and all acts necessary or convenient to, or for the furtherance of, the business and affairs of the Company and who shall have the power and authority to bind the Company. 2.2 Meetings . No meetings of the Members need be held. However, if there is ever more than one member of the Company, meetings of the members (the " Members" ) may be called by a Member, or a combination of Members.

2.3 Action by Written Consent . Any action by the Member may be taken in the form of a written consent rather than at a Member' s meeting. The Company shall maintain a permanent record of all actions taken by the Member 3. RIGHTS AND DUTIES OF THE MEMBER

3.1. Powers of the Member . The Member shall have the power to do any and all acts necessary or convenient to or for the furtherance of the purposes described herein, including all powers, statutory or otherwise, possessed by the Member under the laws of the State of Delaware. Notwithstanding the foregoing, the Member' s powers shall be limited by any limitations imposed by the Certificate of Formation of the Company. 3.2. Indemnification . The Member shall, and any employee or agent of the Company or employee or agent of the Member in connection with services to the Company may, in the Member' s absolute discretion, be indemnified by the Company to the fullest extent permitted by the Act and as may be otherwise permitted by applicable law.

4. TITLE TO COMPANY PROPERTY.

4.1. Title in Company Name. All real and personal property shall be acquired in the name of the Company and title to any property so acquired shall vest in the Company itself rather than in the Member.

5. CAPITAL CONTRIBUTIONS

5.1. Required Contributions . Member shall contribute to the capital of the Company the amount specified on Schedule " A."

5.2. Limitation of Liability of Member . The Member shall not have any liability or obligation for any debts, liabilities or obligations of the Company, or of any agent or employee of the Company, beyond the Member' s capital contribution.

5.3. Loans . If the Member makes any loans to the Company, or advances money on its behalf, the amount of any such loan or advance shall not be deemed an increase in, or contribution to, the capital co ...