Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Lang Paul A
 2. Date of Event Requiring Statement (Month/Day/Year)
12/07/2006		 3. Issuer Name and Ticker or Trading Symbol
ARCH COAL INC [ACI]
(Last)
(First)
(Middle)
ONE CITY PLACE DRIVE, SUITE 300		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Senior VP - Operations
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

ST. LOUIS, MO 63141		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 20,000
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Restricted Stock Units   (1)   (2) Common Stock 2,500 $ (3) D  
Employee Stock Options (Right to Buy) 04/25/2006 04/25/2012 Common Stock 6,000 $ 11.3 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Lang Paul A
ONE CITY PLACE DRIVE
SUITE 300
ST. LOUIS, MO 63141		       Senior VP - Operations  

Signatures

/s/ Gregory A. Billhartz, Attorney-in-Fact 12/12/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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).
(1) The restricted stock units were granted on February 23, 2006 and vest ratably over a three-year period.
(2) The restricted stock units do not expire.
(3) Each restricted stock unit represents a right to receive one share of common stock unless otherwise deferred, at the reporting person's election, pursuant to the Arch Coal, Inc. Executive Deferred Compensation Plan.

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