Petrohawk Amends Tender Offer for 9 7/8% Senior Notes Due 2011

Petrohawk Energy Corporation (NASDAQ: HAWK) has amended the cash tender offer it commenced on June 8, 2006 to purchase any and all of the outstanding $124,490,000 aggregate principal amount of its 9 7/8% Senior Notes due 2011 (collectively referred to as the "Notes"). The amendment reduces the fixed spread component of the formula used to determine the total consideration payable for the Notes in the tender offer from 50 basis points to zero and extends by one business day the Consent Date, the Price Determination Date and the Expiration Date, each as defined in Petrohawk's Offer to Purchase and Consent Solicitation Statement dated June 8, 2006.

Giving effect to these amendments, the total consideration for each $1,000 principal amount of Notes tendered by the Consent Date and accepted for purchase pursuant to the tender offer will be determined on the basis of a yield to April 1, 2008 equal to the sum of (1) the yield (based on the bid sale price) of the 4 5/8% U.S. Treasury Security due March 31, 2008, as calculated by Credit Suisse Securities (USA) LLC in accordance with standard market practice as of the Price Determination Date, which is now 10:00 a.m. EDT on June 23, 2006, plus (2) a fixed spread of 0 basis points. As extended, the Consent Date is now 5:00 p.m. EDT on June 22, 2006. Holders who tender their Notes following the Consent Date but prior to the Expiration Date, which is now 5:00 p.m. EDT on July 10, 2006 will be eligible to receive the total consideration less the $30 consent payment. Petrohawk will pay accrued interest on all Notes to the date of purchase.

The other terms of the tender offer and the related consent solicitation remain unchanged. Both the tender offer and the consent solicitation are subject to the completion of Petrohawk's pending merger with KCS Energy, Inc.

Earlier today Petrohawk reached an agreement with a financial institution that purports to be the investment manager for beneficial owners of $66,484,000, or 53.4%, of the aggregate principal amount of the outstanding Notes. The agreement provides for the tender of all of these Notes to Petrohawk prior to the new Consent Date.

As previously announced, Petrohawk has retained Credit Suisse Securities (USA) LLC to serve as the Dealer Manager for the tender offer and the Solicitation Agent for the related consent solicitation. Computershare Trust Company, N.A. serves as depositary for the tender offer, and Georgeson Shareholder Communications, Inc. serves as Information Agent for the tender offer. Requests for documents, including today's amendment to the Offer to Purchase and Consent Solicitation Statement, may be directed to Georgeson Shareholder Communications, Inc. by telephone at 800-279-7074 or 212-440-9800, or in writing at 17 State Street, 10th Floor, New York, NY 10004. Questions regarding the tender offer or consent solicitation also may be directed to Credit Suisse Securities (USA) LLC by telephone at 800-820-1653 or 212-538-0652, or in writing at Eleven Madison Avenue, New York, NY 10010.

This press release does not constitute an offer to purchase or a solicitation of acceptance of the tender offer, which may be made only pursuant to the terms of the amended Offer to Purchase and Consent Solicitation Statement and related Consent and Letter of Transmittal. In any jurisdiction where the laws require the tender offer to be made by a licensed broker or dealer, the tender offer will be deemed made on behalf of Petrohawk by Credit Suisse or one or more registered brokers or dealers under the laws of such jurisdiction.