SUPPLEMENTAL INDENTURE No. 2 dated as of December 29, 2005 among CENTURY ALUMINUM COMPANY, as Issuer NSA GENERAL PARTNERSHIP, as a Guarantor and WILMINGTON TRUST COMPANY, as Trustee 71/2% SENIOR NOTES DUE 2014

Exhibit 4.6

SUPPLEMENTAL INDENTURE No. 2

dated as of December 29, 2005

among

CENTURY ALUMINUM COMPANY,
as Issuer

NSA GENERAL PARTNERSHIP,
as a Guarantor

and

WILMINGTON TRUST COMPANY,
as Trustee

7¹/₂% SENIOR NOTES DUE 2014

     THIS SUPPLEMENTAL INDENTURE NO. 2 (this “Supplemental Indenture”), entered into as of December 29, 2005, and effective from and after December 20, 2005, among Century Aluminum Company, a Delaware corporation (the “Company”), NSA General Partnership, a Kentucky general partnership, as a Guarantor (the “Undersigned”) and Wilmington Trust Company, as trustee (the “Trustee”).

RECITALS

     WHEREAS, the Company, the Guarantors party thereto and the Trustee entered into the Indenture, dated as of August 26, 2004 (the “Indenture”), relating to the Company’s 7¹/2% Senior Notes due 2014 (the “Notes”), as amended by Supplemental Indenture No. 1, dated as of July 25, 2005, among the Company, Century Aluminum of Kentucky LLC and the Trustee; and

     WHEREAS, as a condition to the Trustee entering into the Indenture and the purchase of the Notes by the Holders, the Company agreed pursuant to the Indenture to cause any newly acquired or created Domestic Restricted Subsidiaries (other than Foreign-Owned Parent Holding Companies) to provide Guaranties.

AGREEMENT

     NOW, THEREFORE, in consideration of the premises and mutual covenants herein contained and intending to be legally bound, the parties to this Supplemental Indenture, effective from and after December 20, 2005, hereby agree as follows:

     Section 1. Capitalized terms used herein and not otherwise defined herein are used as defined in the Indenture.

     Section 2. The Undersigned, by its execution of this Supplemental Indenture, agrees to be a Guarantor under the Indenture and to be bound by the terms of the Indenture applicable to Guarantors, including, but not limited to, Article 10 thereof.

     Section 3. This Supplemental Indenture shall be governed by and construed in accordance with the laws of the State of New York.

     Section 4. This Supplemental Indenture may be signed in various counterparts which together will constitute one and the same instrument.

     Section 5. This Supplemental Indenture is an amendment supplemental to the Indenture and the Indenture and this Supplemental Indenture will henceforth be read together.

     Section 6. The Trustee makes no representation as to the validity or adequacy of this Supplemental Indenture or the recitals contained herein.

     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written.

		CENTURY ALUMINUM COMPANY,      as Issuer
		By:		/s/ Daniel J. Krofcheck
				Name:		Daniel J. Krofcheck
				Title:		Vice President and Treasurer
		NSA GENERAL PARTNERSHIP,      as a Guarantor
		By:		CENTURY KENTUCKY, INC., its general partner
				By:		/s/ Daniel J. Krofcheck
						Name:		Daniel J. Krofcheck
						Title:		Vice President and Treasurer
		By:		SKYLINER, LLC, its general partner
				By:		/s/ Daniel J. Krofcheck
						Name:		Daniel J. Krofcheck
						Title:		Vice President and Treasurer
		WILMINGTON TRUST COMPANY,      as Trustee
		By:		/s/ Kristin L Moore
				Name:		Kristin L. Moore
				Title:		Financial Services Officer