Sec Form 4 Filing - LEER STEVEN F @ ARCH COAL INC - 2012-02-23

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person LEER STEVEN F 2. Issuer Name and Ticker or Trading Symbol ARCH COAL INC [ ACI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chairman and CEO (Last) (First) (Middle) ONECITYPLACE DRIVE 3. Date of Earliest Transaction (MM/DD/YY) 02/23/2012 (Street) ST. LOUIS, MO63141 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 02/23/2012 M( 1 ) 218,900 A $ 9.08 241,320 D Common Stock 02/23/2012 S( 1 ) 145,933 D $ 13.83 95,387 D Common Stock 02/23/2012 S( 1 ) 72,967 D $ 13.84 22,420 D Common Stock 63,797 I By 401(k) plan

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Employee Stock Options $ 13.93 02/23/2012 A 206,700 ( 2 ) 02/23/2022 Common Stock 206,700 $ 0 206,700 D Restricted Stock Units $ 13.93 02/23/2012 A 81,850 ( 3 ) ( 4 ) Common Stock 81,850 $ 0 81,850 D Employee Stock Options $ 9.08 02/23/2012 M( 1 ) 218,900 ( 5 ) 02/29/2012 Common Stock 218,900 $ 0 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other LEER STEVEN F ONECITYPLACE DRIVE ST. LOUIS, MO63141 X Chairman and CEO Signatures /s/ Jon S. Ploetz, Attorney-in-Fact 02/27/2012 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The transactions were made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. ( 2 )The options vest ratably over 3 years as follows: 68,900 shares vest on February 23, 2013; 68,900 shares vest on February 23, 2014; and 68,900 shares vest on February 23, 2015. ( 3 )On February 23, 2012, the reporting person received 81,850 restricted stock units. All of these restricted stock units vest on February 23, 2015. ( 4 )The restricted stock units do not expire. ( 5 )The reporting person received 218,900 stock options on February 28, 2002. The stock options vested as follows: 54,725 stock options vested on February 28, 2003; 54,725 stock options vested on February 29, 2004; 54,724 stock options vested on February 28, 2005; and 54,726 stock options vested on February 28, 2006.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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