Petrohawk 2012 Annual Report

Petrohawk Energy Corporation (Petrohawk) provides periodic reports to holders of Petrohawks senior notes as required in accordance with the reporting covenants under the applicable indentures. A copy of Petrohawks 2012 Annual Report will be provided to the holders of Petrohawks outstanding senior notes today. Petrohawks financial statements are prepared in accordance with United States accounting standards whereas BHP Billiton Group financial statements are prepared in accordance with International Financial Reporting Standards and include the impact of the purchase price paid for Petrohawk. In addition, the consolidated financial statements contained in Annual Report are based on Petrohawks historical accounting activities and do not reflect the acquisition of Petrohawk by BHP Billiton or any of the fair value calculations that were performed in conjunction with the business combination accounting performed by BHP Billiton. For the avoidance of doubt, the results of operations, financial position, cash flows and disclosures included in the Petrohawk 2012 Annual Report are not indicative of the contribution of Petrohawk to the potential results of BHP Billiton. BHP Billiton purchased Petrohawk on 20 August 2011 and therefore only consolidates Petrohawks results in its financial statements from that date. Visit www.bhpbilliton.com/home/investors/news/Pages/Articles/Petrohawk-2012-Annual-Report.aspx for a copy of the report