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 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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1. Name and Address of Reporting Person * Glencore AG   2. Issuer Name and Ticker or Trading Symbol CENTURY ALUMINUM CO [CENX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) BAARERMATTSTRASSE 3, P.O. BOX 1301 3. Date of Earliest Transaction (Month/Day/Year) 03/31/2017 (Street) BAAR, V8 CH-6341 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 03/31/2017   C   4,795 A (1) (2) 37,448,210 D (3)

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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 (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

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 (Month/Day/Year)

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

Series A Convertible Preferred Stock

(2)

03/31/2017

C

47.95

(2)

(2)

Common Stock

4,795

(2)

75,577.37

D (3)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Glencore AG BAARERMATTSTRASSE 3 P.O. BOX 1301 BAAR, V8 CH-6341		X
GLENCORE INTERNATIONAL AG BAARERMATTSTRASSE 3 P.O. BOX 1301 BAAR, V8 CH-6341		X
Glencore plc BAARERMATTSTRASSE 3 P.O. BOX 1301 BAAR, V8 CH-6341		X

Signatures

GLENCORE AG By: /s/ David Streule, Officer		04/03/2017
**Signature of Reporting Person		Date
GLENCORE AG By: /s/ Stephan Huber, Officer		04/03/2017
**Signature of Reporting Person		Date
GLENCORE INTERNATIONAL AG By: /s/ Robin Scheiner, Officer		04/03/2017
**Signature of Reporting Person		Date
GLENCORE INTERNATIONAL AG By: /s/ Ian Sloman, Officer		04/03/2017
**Signature of Reporting Person		Date
GLENCORE PLC By: /s/ John Burton, Company Secretary		04/03/2017
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Represents shares of Common Stock acquired upon conversion of 47.95 shares of Series A Convertible Preferred Stock on March 31, 2017.
(2)	Each share of Series A Convertible Preferred Stock is convertible into 100 shares of 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)	The shares of Common Stock reported in Table I and the shares of Series A Convertible Preferred Stock reported in Table II are held directly by Glencore AG, a direct wholly-owned subsidiary of Glencore International AG, and indirectly by Glencore International AG and its parent, Glencore plc.

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