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 *
  GLENCORE INTERNATIONAL PLC
2. Date of Event Requiring Statement (Month/Day/Year)
05/23/2011
3. Issuer Name and Ticker or Trading Symbol
CENTURY ALUMINUM CO [CENX]
(Last)
(First)
(Middle)
BAARERMATTSTRASSE 3, P.O. BOX 777
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BAAR, V8 CH-6341
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 36,374,058
I
See Footnote (1)

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
Series A Convertible Preferred Stock   (2)   (2) Common Stock 8,125,546 $ (2) I See Footnote (1)
Cash Settled Total Return Swap (obligation to buy) 09/17/2012 09/17/2012 Common Stock 4,729,302 (3) (4) (5) $ 9.7193 (3) (4) (5) I See Footnote (7)
Cash Settled Total Return Swap (obligation to buy) 03/11/2013 03/11/2013 Common Stock 4,400,000 (3) (5) (6) $ 16.6582 (3) (5) (6) I See Footnote (7)
Stock Options   (8)   (8) Common Stock 2,000 $ 15.87 I See Footnote (8)
Stock Options   (9)   (9) Common Stock 2,000 $ 15.17 I See Footnote (9)
Stock Options   (10)   (10) Common Stock 3,000 $ 7.34 I See Footnote (10)
Stock Options   (11)   (11) Common Stock 3,000 $ 24.1 I See Footnote (11)
Stock Options   (12)   (12) Common Stock 3,000 $ 26.7 I See Footnote (12)
Stock Options   (13)   (13) Common Stock 3,000 $ 35.9 I See Footnote (13)
Stock Options   (14)   (14) Common Stock 3,000 $ 55.06 I See Footnote (14)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GLENCORE INTERNATIONAL PLC
BAARERMATTSTRASSE 3
P.O. BOX 777
BAAR, V8 CH-6341
    X    

Signatures

GLENCORE INTERNATIONAL PLC, By: /s/ Steven Kalmin 06/01/2011
**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 shares of Common Stock reported on Table I and the shares of Series A Convertible Preferred Stock reported on Table II are owned directly by Glencore AG, a direct wholly-owned subsidiary of Glencore International AG, and indirectly by Glencore International plc, the parent company of Glencore International AG.
(2) Each share of Series A Convertible Preferred Stock is convertible into 100 shares of the Common Stock at the times and under the circumstances described in the Certificate of Designation for the Series A Convertible Preferred Stock. The Series A Convertible Preferred Stock has no expiration date.
(3) On July 2, 2010, Glencore International AG ("Glencore International") entered into a Master Terms and Conditions for Swap Transactions agreement (the "Swap Agreement") with Citigroup Global Markets Inc. ("Citi"), pursuant to which Glencore International and Citi may, from time to time, enter into cash-settled total return swaps (the "Swaps").
(4) Pursuant to the Swap Agreement, on September 15, 2010, Glencore International received economic exposure pursuant to a Swap entered into between Glencore International and Citi under which, upon expiration of a two-year term, (i) Glencore International will be obligated to make a cash payment to Citi with respect to any depreciation in the volume weighted average price of the 4,729,302 shares of common stock referenced by the Swap (the "Subject Shares") from the $9.719270 per share volume weighted average price calculated during the initial averaging period for the Swap (which ended on the transaction date) to the volume weighted average price of the Subject Shares during the final valuation period preceding the expiration of the term of the Swap, or (ii) Citi will be obligated to make a cash payment to Glencore International with respect to any appreciation in such volume weighted average price based on the above period.
(5) In addition, under the terms of the Swap Agreement, generally, Glencore International will be obligated to post cash collateral to Citi and pay to Citi certain fees and commissions and Citi will be obligated to pay to Glencore International an amount in cash equal to any dividends that would have been paid by the Company on the Subject Shares.
(6) Pursuant to the Swap Agreement, on March 11, 2011, Glencore International received economic exposure pursuant to a Swap entered into between Glencore International and Citi under which, upon expiration of a two year term, (i) Glencore International will be obligated to make a cash payment to Citi with respect to any depreciation in the volume weighted average price of the 4,400,000 shares of common stock referenced by the Swap (the "Subject Shares") from the $16.6582 per share volume weighted average price calculated during the initial averaging period for the Swap (which ended on the transaction date) to the volume weighted average price of the Subject Shares during the final valuation period preceding the expiration of the term of the Swap, or (ii) Citi will be obligated to make a cash payment to Glencore International with respect to any appreciation in such volume weighted average price based on the above period.
(7) The cash settled total return swap reported in Table II is held directly by Glencore International and may be deemed to be beneficially owned indirectly by its parent company, Glencore International plc. The cash settled total return swap does not give the reporting person or Glencore International direct or indirect voting, investment or dispositive control over any securities of the issuer, and accordingly, Glencore International and Glencore International plc disclaim any beneficial ownership in the Subject Shares.
(8) June 28, 2001 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(9) June 25, 2002 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(10) June 25, 2003 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(11) July 19, 2004 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(12) August 11, 2005 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(13) June 12, 2006 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.
(14) May 24, 2007 grant of stock options to Mr. Willy R. Strothotte, a director of the issuer, who holds such options as nominee for Glencore AG. Options vested and became exercisable in four equal installments ending on the first anniversary of the date of grant. The options will expire and cease to be exercisable on the tenth anniversary of the date of grant.

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