FIRST AMENDMENT AND WAIVER TO AMENDED AND RESTATED CREDIT AGREEMENT

Exhibit 10.86

FIRST AMENDMENT AND WAIVER TO AMENDED AND RESTATED CREDIT

AGREEMENT

THIS FIRST AMENDMENT AND WAIVER, dated as of September 16, 2005 (the “Amendment and Waiver”), to AMENDED AND RESTATED CREDIT AGREEMENT, dated as of April 1, 2005 (the “ Credit Agreement ”; capitalized terms used but not defined herein shall have the meanings given them in the Credit Agreement) by and among CONSOL Energy Inc. (the “ Borrower ”), certain subsidiaries of the Borrower listed on the signature pages hereof (collectively the “ Guarantors ; the Borrower and the Guarantors are collectively referred to as the “ Loan Parties ”), PNC Bank, National Association and Citicorp North America, Inc., as co-administrative agents, and PNC Bank, National Association, as paying agent (the “ Paying Agent ”).

WITNESSETH

WHEREAS, in connection with the Permitted Gas Properties Transaction that closed in August of 2005, it is anticipated that the stock of CNX Gas Corporation (a portion of the stock of which is held by CONSOLIDATION COAL COMPANY, one of the Loan Parties) will be registered with the Securities and Exchange Commission and listed on the New York Stock Exchange;

WHEREAS, pursuant to Section 6.1.10.2 of the Credit Agreement, none of the Loan Parties is permitted to hold or intend to hold margin stock in such amounts so that more than 25% of the reasonable value of the assets of any Loan Party is margin stock;

WHEREAS, on September 2, 2005 Consol Sales Company officially changed its name to CONSOL Energy Sales Company (the “ Loan Party Name Change ”);

WHEREAS, pursuant to the terms of Section 8.2.14(a) of the Credit Agreement and the terms of various of the Loan Documents, the Loan Parties are required to provide to the Paying Agent and the Lenders, and as applicable, the Collateral Trustee, a written notice detailing any name change by any Loan Party, at least thirty (30) days before the effective date of any such change.

NOW, THEREFORE, the parties hereto, in consideration of the mutual covenants and agreements herein contained and intending to be legally bound hereby, covenant and agree as follows:

1. Recitals . The recitals set forth above are hereby incorporated herein by reference.

2. Amendment to Credit Agreement . Section 6.1.10.2 [Margin Stock] of the Credit Agreement is hereby amended and restated in its entirety as follows:

“None of the Loan Parties engages or intends to engage principally, or as one of its important activities, in the business of extending credit for the purpose, immediately, incidentally or ultimately, of purchasing or carrying margin stock (within the meaning of Regulation U). No part of the proceeds of any Loan has

been or will be used as a “Purpose Credit” (as defined in Regulation U) to purchase or carry any margin stock or to extend credit to others for the purpose of purchasing or carrying any margin stock or to refund Indebtedness originally incurred for such purpose, or for any purpose which entails a violation of or which is inconsistent with the provisions of the regulations of the Board of Governors of the Federal Reserve System.”

3. Waiver . The Lenders hereby authorize the Paying Agent, on their behalf, to waive, or cause to be waived, any and all violations of the Credit Agreement and any other Loan Document arising from any failure of any Loan Party to provide at least thirty (30) day’s written notice detailing the Loan Party Name Change and the effective date of the Loan Party Name Change and to take any and all other actions in furtherance thereof.

4. Condition Precedent . The effectiveness of Section 2 [Amendment of Credit Agreement] hereof is expressly conditioned upon satisfaction of the conditions set forth in items (a) and (b) below being satisfied to the satisfaction of the Paying Agent, and the effectiveness of Section 3 [Waiver] hereof is expressly conditioned upon satisfaction of the condition set forth in item (a) below being satisfied to the satisfaction of the Paying Agent:

(a) The Paying Agent shall have received from the Borrower, each Loan Party, and the Required Lenders an executed original of this Amendment and Waiver in form and substance satisfactory to the Paying Agent.

(b) The Loan Parties shall have delivered a completed and fully executed Federal Reserve Form U-1 [Statement of Purpose for an Extension of Credit Secured by Margin Stock] confirming that the Loans will not be used, in whole or in part, to purchase or carry margin stock

5. Incorporation into Agreements . The terms, provisions, representations, warranties and covenants set forth herein shall be incorporated into the Credit Agreement by this reference. All terms, provisions, representations, warranties and covenants set forth herein shall be a part of the Credit Agreement as if originally contained therein.

6. Full Force and Effect . Except as expressly modified by this Amendment, all of the terms, conditions, representations, warranties and covenants contained in the Credit Agreement shall continue in full force and effect, including without limitation, all liens and security interests securing the Borrower’s obligations under the Secured Debt.

7. Counterparts . This Amendment may be executed by different parties hereto in any number of separate counterparts, each of which, when so executed and delivered shall be an original and all such counterparts shall together constitute one and the same instrument.

8. Severability . If any term of this Amendment or any application thereof shall be held to be invalid, illegal or unenforceable, the validity of other terms of this Amendment or any other application of such term shall in no way be affected thereby.

9. Entire Agreement . This Amendment sets forth the entire agreement and understanding of the parties with respect to the amendment to the Credit Agreement

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contemplated hereby and supersedes all prior understandings and agreements, whether written or oral, between the parties hereto relating to such amendments. No representation, promise, inducement or statement of intention has been made by any party that is not embodied in this Amendment, and no party shall be bound by or liable for any alleged representation, promise, inducement or statement of intention not set forth herein.

10. Governing Law . This Amendment shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the internal laws of the State of Pennsylvania applicable to contracts made and to be performed in said State.

[SIGNATURES APPEAR ON FOLLOWING PAGES]

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[SIGNATURE PAGE TO FIRST AMENDMENT AND WAIVER TO

AMENDED AND RESTATED CREDIT AGREEMENT]

IN WITNESS WHEREOF, the parties hereto, by their officers thereunto duly authorized, have executed this First Amendment and Waiver to Amended and Restated Credit Agreement as of the day and year first above written with the intention that it constitute a sealed instrument.

[SIGNATURE PAGE TO FIRST AMENDMENT AND WAIVER TO

AMENDED AND RESTATED CREDIT AGREEMENT]

[SIGNATURE PAGE TO FIRST AMENDMENT AND WAIVER TO

AMENDED AND RESTATED CREDIT AGREEMENT]

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amended and restated CREDIT AGREEMENT]

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AMENDED AND RESTATED CREDIT AGREEMENT]

[SIGNATURE PAGE TO FIRST AMENDMENT AND WAIVER TO

AMENDED AND RESTATED CREDIT AGREEMENT]

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