UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

(Amendment No. 1)

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) March 7, 2012

PEABODY ENERGY CORPORATION

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (314) 342-3400

N/A

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

EXPLANATORY NOTE

This amendment to the Current Report on Form 8-K filed by Peabody Energy Corporation (the “Company”) on March 9, 2012 is being filed to provide disclosure regarding the Employment Agreement between the Company and Christopher J. Hagedorn that was entered into as of March 28, 2012.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(b) Information regarding changes in roles and responsibilities of Richard A. Navarre and Eric Ford is incorporated herein by reference from Item 8.01 below.

(c) Information regarding the appointment of Christopher J. Hagedorn is incorporated herein by reference from Item 8.01 below.

On March 28, 2012, the Company and Mr. Hagedorn entered into an employment agreement pursuant to which he accepted employment as President Asia and Trading, commencing as of March 15, 2012. The employment agreement provides for an initial three-year term which automatically renews for a one-year period at the end of the initial term and, if applicable, any renewal period, unless written notice is given by either party at least 90 days before the end of the applicable period.

The employment agreement describes the compensation arrangements applicable to Mr. Hagedorn during his employment with the Company, which includes:

Following a termination of employment for any reason during the term of employment or any renewal period, Mr. Hagedorn will be entitled to receive: (1) base salary accrued but unpaid prior to such termination; (2) any reimbursable business expenses not yet reimbursed; (3) any vacation time accrued but unused as of the date of such termination; and (4) any benefits accrued and vested under any of the Company’s employee benefit programs, plans and practices on or prior to the date of termination. In addition:

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The employment agreement provides for confidentiality obligations during and following Mr. Hagedorn’s employment and includes noncompetition provisions that are effective during, and for one year following, his employment, and nonsolicitation provisions that are effective during, and for two years following, his employment.

The foregoing description is only a summary of certain provisions of the employment agreement, and is qualified in its entirety by reference to the employment agreement itself, which is filed as Exhibit 10.1 hereto and which is incorporated by reference herein.

Item 8.01 Other Events.

On March 7, 2012, Peabody Energy Corporation (“Peabody” or the “Company”) announced a new global organizational structure, with the creation of geographic business units in the Americas, Australia and Asia to reflect the growing size and scope of Peabody’s global footprint. The new organization positions the Company for maximum success amid unique geographic market conditions and opportunities, by committing dedicated business unit teams to manage all aspects of the platform including safety, operations, marketing, project delivery and support functions.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

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