sc13da5.htm

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No.5)1

Patriot Coal Corporation

(Name of Issuer)

Common Stock, $0.01 par value per share

(Title of Class of Securities)

70336T 10 4

(CUSIP Number)

John A. Tisdale, Esq.

General Counsel

ArcLight Capital Holdings, LLC

200 Clarendon Street, 55th Floor

Boston, MA 02117

Telephone: (617) 531−6300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

March 9, 2010

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 13d-1(f) or 240.13d-1(g), check the following box [ ].

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

1 The remainder of this cover page shall be filled out for a reporting person’s initial filling on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934, as amended (the "Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 2 of 18 Pages

1	NAME OF REPORTING PERSON ArcLight Energy Partners Fund I, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 6,165,049
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 6,165,049
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,165,049
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.8%
14	TYPE OF REPORTING PERSON (See Instructions) PN

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 3 of 18 Pages

1	NAME OF REPORTING PERSON ArcLight Energy Partners Fund II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 4,936,778
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 4,936,778
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,936,778
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.4%
14	TYPE OF REPORTING PERSON (See Instructions) PN

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 4 of 18 Pages

1	NAME OF REPORTING PERSON ArcLight PEF GP, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 6,165,049*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 6,165,049
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 6,165,049
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.8%
14	TYPE OF REPORTING PERSON (See Instructions) CO

* Solely in its capacity as the general partner of ArcLight Energy Partners Fund I, L.P.

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 5 of 18 Pages

1	NAME OF REPORTING PERSON ArcLight PEF GP II, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 4,936,778*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 4,936,778
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,936,778
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.4%
14	TYPE OF REPORTING PERSON (See Instructions) CO

* Solely in its capacity as the general partner of ArcLight Energy Partners Fund II, L.P.

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 6 of 18 Pages

1	NAME OF REPORTING PERSON ArcLight Capital Holdings, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 11,101,827*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 11,101,827
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 11,101,827
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.2%
14	TYPE OF REPORTING PERSON (See Instructions) CO

* Solely in its capacity as the manager of ArcLight PEF GP, LLC, the general partner of ArcLight Energy Partners Fund I, L.P. and ArcLight PEF GP II, LLC, the general partner of ArcLight Energy Partners Fund II, L.P.

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 7 of 18 Pages

1	NAME OF REPORTING PERSON Daniel R. Revers*
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 11,101,827*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 11,101,827
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 11,101,827
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.2%
14	TYPE OF REPORTING PERSON (See Instructions) IN

* Solely in his capacity as the manager of ArcLight Capital Holdings, LLC, the manager of ArcLight PEF GP, LLC which is the general partner of ArcLight Energy Partners Fund I, L.P. and ArcLight PEF GP II, LLC, the general partner of ArcLight Energy Partners Fund II, L.P. Mr. Revers disclaims beneficial ownership of the shares of Common Stock held by the ArcLight Funds, except to the extent of his pecuniary interest in such funds.

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 8 of 18 Pages

1	NAME OF REPORTING PERSON Robb E. Turner*
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 11,101,827*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 11,101,827
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 11,101,827
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.2%
14	TYPE OF REPORTING PERSON (See Instructions) IN

* Solely in his capacity as the manager of ArcLight Capital Holdings, LLC, the manager of ArcLight PEF GP, LLC which is the general partner of ArcLight Energy Partners Fund I, L.P. and ArcLight Energy Partners Fund II, L.P. Mr. Turner disclaims beneficial ownership of the shares of Common Stock held by the ArcLight Funds, except to the extent of his pecuniary interest in such funds.

SCHEDULE 13D

CUSIP No. 70336T 10 4				Page 9 of 18 Pages

1	NAME OF REPORTING PERSON John F. Erhard*
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)				(a) o (b) S
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions) OO
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)				o
6	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES		7	SOLE VOTING POWER
BENEFICIALLY OWNED BY		8	SHARED VOTING POWER 11,101,827*
EACH REPORTING		9	SOLE DISPOSITIVE POWER
PERSON WITH		10	SHARED DISPOSITIVE POWER 11,101,827
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 11,101,827
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)				T
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.2%
14	TYPE OF REPORTING PERSON (See Instructions) IN

* Solely in his capacity as a principal of ArcLight Capital Holdings, LLC, the manager of ArcLight PEF GP, LLC which is the general partner of ArcLight Energy Partners Fund I, L.P. and ArcLight Energy Partners Fund II, L.P. Mr. Erhard disclaims beneficial ownership of the shares of Common Stock held by the ArcLight Funds, except to the extent of his pecuniary interest in such funds.

This Amendment No. 5 relates to shares of Common Stock of Patriot Coal Corporation (the "Issuer"). This Amendment to the Schedule 13D filed on August 1, 2008 (File No. 005-83427), as amended on August 18, 2008, January 21, 2009, February 11, 2010 and March 8, 2010, is being filed by the following persons to amend and supplement the Items set forth below: ArcLight Energy Partners Fund I, L.P. ("ArcLight Fund I"), ArcLight Energy Partners Fund II, L.P. ("ArcLight Fund II", and together with ArcLight Fund I, the "ArcLight Funds"), ArcLight PEF GP, LLC ("ArcLight PEF GP"), ArcLight PEF GP II, LLC ("ArcLight PEF GP II"), ArcLight Capital Holdings, LLC ("ArcLight Capital Holdings", and together with the ArcLight Funds, A rcLight PEF GP and ArcLight PEF GP II the "ArcLight Entities"), Daniel R. Revers ("Mr. Revers"), Robb E. Turner ("Mr. Turner") and John F. Erhard ("Mr. Erhard", and together with the ArcLight Entities, Mr. Revers and Mr. Turner the "ArcLight Related Parties"). Capitalized terms used herein and not otherwise defined shall have the meaning ascribed to them in the Reporting Persons' Schedule 13D, as amended.

Item 5. Interest in Securities of the Issuer

Item 5(a) and (b) of the Schedule 13D is hereby amended and supplemented as follows:

On March 9, 2010, ArcLight Fund I and ArcLight Fund II sold 1,110,637 and 889,363 shares of Common Stock, respectively, to Credit Suisse Securities (USA) LLC for $20.05 per share in a transaction effected pursuant to Rule 144 of the Securities Act of 1933, as amended (the "Sale").

Following the Sale, and as of March 11, 2010, (i) the ArcLight Related Parties collectively may be deemed to beneficially own 11,101,827 shares of Common Stock, representing approximately 12.2% of the outstanding shares of Common Stock (based on 90,870,249 shares of Common Stock reported by the Issuer as outstanding as of February 19, 2010) and (ii) the interests in the Common Stock of each of the ArcLight Related Parties is as follows:

ArcLight Fund I has the shared power to vote, direct the voting of, dispose of and direct the disposition of 6,165,049 shares of Common Stock, representing approximately 6.8% of the outstanding shares of Common Stock. Such shares may be deemed to be owned beneficially (solely for the purposes of Rule 13d-3 under the Act) by ArcLight PEF GP and ArcLight Capital Holdings.

ArcLight Fund II has the shared power to vote, direct the voting of, dispose of and direct the disposition of 4,936,778 shares of Common Stock, representing approximately 5.4% of the outstanding shares of Common Stock. Such shares may be deemed to be owned beneficially (solely for the purposes of Rule 13d-3 under the Act) by ArcLight PEF GP II and ArcLight Capital Holdings.

ArcLight PEF GP, as general partner of ArcLight Fund I, and ArcLight Capital Holdings as manager of ArcLight PEF GP, may be deemed to beneficially own the shares of Common Stock held by ArcLight Fund I. ArcLight PEF GP II, as general partner of ArcLight Fund II, and ArcLight Capital Holdings as manager of ArcLight PEF GP II, may be deemed to beneficially own the shares of Common Stock held by the ArcLight Funds. In addition, Messrs. Revers and Turner, as managers of ArcLight Capital Holdings may be deemed to beneficially own the shares of Common Stock held by the ArcLight Funds.

Item 5(c) is hereby amended and supplemented by adding the following:

Except as otherwise set forth in the Schedule 13D, there have been no transactions in the securities of the Issuer effected by the ArcLight Related Parties in the last 60 days

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

ARCLIGHT ENERGY PARTNERS FUND I, L.P.

By: ArcLight PEF GP, LLC, its

General Partner

By: ArcLight Capital Holdings,

LLC, its Manager

By: /s/ Daniel R. Revers

Name: Daniel R. Revers

Title: Manager

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

ARCLIGHT ENERGY PARTNERS FUND II, L.P.

By: ArcLight PEF GP II, LLC,

its General Partner

By: ArcLight Capital Holdings, LLC,

its Manager

By: /s/ Daniel R. Revers

Name: Daniel R. Revers

Title: Manager

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

ARCLIGHT PEF GP, LLC

By: ArcLight Capital Holdings, LLC,

its Manager

By: /s/ Daniel R. Revers

Name: Daniel R. Revers

Title: Manager

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

ARCLIGHT PEF GP II, LLC

By: ArcLight Capital Holdings, LLC,

its Manager

By: /s/ Daniel R. Revers

Name: Daniel R. Revers

Title: Manager

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

ARCLIGHT CAPITAL HOLDINGS, LLC

By: /s/ Daniel R. Revers

Name: Daniel R. Revers

Title: Manager

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

/s/ Daniel R. Revers

Daniel R. Revers

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

/s/ Robb E. Turner

Robb E. Turner

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 11, 2010

/s/ John F. Erhard

John F. Erhard