FIRST SUPPLEMENTAL INDENTURE DATED AS OF AUGUST 29, 2012 to INDENTURE dated as of August 20, 2012 among TRONOX FINANCE LLC, as Issuer TRONOX LIMITED as Parent THE GUARANTORS NAMED THEREIN as Guarantors and WILMINGTON TRUST, NATIONAL ASSOCIATION as Trustee

Exhibit 4.3

FIRST SUPPLEMENTAL INDENTURE

DATED AS OF AUGUST 29, 2012

to

INDENTURE

dated as of August 20, 2012

among

TRONOX FINANCE LLC,

as Issuer

TRONOX LIMITED

as Parent

THE GUARANTORS NAMED THEREIN

as Guarantors

and

WILMINGTON TRUST, NATIONAL ASSOCIATION

as Trustee

THIS FIRST SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of August 29, 2012 Tronox Limited, a public limited company organized under the laws of Western Australia, Australia (the “Parent”), Tronox Finance LLC, a Delaware limited liability company (the “Issuer”), the Parent, the Guarantors (as defined in the Indenture referred to herein) and Wilmington Trust, National Association, as trustee under the Indenture referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Issuer, the Parent and the Guarantors have heretofore executed and delivered to the Trustee an indenture (the “Indenture”), dated as of August 20, 2012 providing for the issuance of 6.375% Senior Notes due 2020 (the “Notes”);

WHEREAS, the Section 9.01(1) of the Indenture provides that the Indenture can be amended without the consent of Holders “to cure any ambiguity, omission, mistake, defect or inconsistency;” and

WHEREAS, pursuant to Sections 9.01 and 9.06 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture, without the consent of Holders.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Issuer, Parent, the Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1. CAPITALIZED TERMS. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2. AMENDMENT TO SECTION. The definition of Permitted Refinancing Indebtedness is hereby amended by the addition of the following prior to the period at the end of paragraph (5): “or (b) the Issuer or a Guarantor”.

3. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

4. COUNTERPARTS. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

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5. EFFECT OF HEADINGS. The Section headings herein are for convenience only and shall not affect the construction hereof.

6. THE TRUSTEE. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Parent, Guarantors and the Issuer.

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

Signature Page to First Supplemental Indenture

Signature Page to Reserve Certificate

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture

Signature Page to First Supplemental Indenture