Mission Resources Clarifies Press Release

Mission Resources Corporation (Nasdaq:MSSN) announced
yesterday in a press release that it had signed a definitive agreement
selling non-operated interests in the Goldsmith and Wasson oil fields,
located in Ector and Yoakum Counties, Texas, to XTO Energy Inc.
   The press release incorrectly stated that the joint proxy
statement/prospectus relating to the acquisition of Mission by
Petrohawk Energy Corporation was not yet final and would be amended.
The joint proxy statement/prospectus has been finalized, and as
previously announced, the proxy statements and related materials for
the respective companies were mailed June 28, 2005 to all stockholders
of Petrohawk and Mission as of June 13, 2005, the record date for each
company. Stockholders may also obtain a copy of these materials and
information on voting procedures by contacting Georgeson Shareholder
Communications, Inc. at 800-790-6795.
   About Mission Resources: Mission Resources Corporation is a
Houston-based independent exploration and production company that
drills for, acquires, develops and produces natural gas and crude oil
primarily in the Permian Basin (in West Texas and Southeastern New
Mexico), along the Texas and Louisiana Gulf Coast and in both the
state and federal waters of the Gulf of Mexico.

   This press release contains "forward-looking statements" within
the meaning of Section 27A of the Securities Act of 1933, as amended,
and Section 21E of the Securities Exchange Act of 1934, as amended.
These forward-looking statements are subject to certain risks, trends
and uncertainties that could cause actual results to differ materially
from those projected. Among those risks, trends and uncertainties are
our estimate of the sufficiency of our existing capital sources, our
ability to raise additional capital to fund cash requirements for
future operations, the uncertainties involved in estimating quantities
of proved oil and natural gas reserves, in prospect development and
property acquisitions and in projecting future rates of production,
the timing of development expenditures and drilling of wells, and the
operating hazards attendant to the oil and gas business. In
particular, careful consideration should be given to cautionary
statements made in the various reports the Company has filed with the
Securities and Exchange Commission. Mission undertakes no duty to
update or revise these forward-looking statements.
   As announced on April 4, 2005, Mission and Petrohawk Energy
Corporation (Nasdaq:HAWK) ("Petrohawk") have entered into a
definitive agreement whereby Petrohawk will acquire Mission for a
combination of Petrohawk stock, cash and the assumption of debt. The
acquisition is subject to customary conditions, including the approval
of the stockholders of both companies. The transaction is expected to
close in the third quarter of 2005.
   In connection with the acquisition, Petrohawk and Mission will
file materials relating to the acquisition with the SEC, including a
joint proxy statement/prospectus on Form S-4 that was filed with the
SEC by Petrohawk. The joint proxy statement/prospectus contains
important information about the acquisition. Investors and security
holders of Petrohawk and Mission are urged to read the joint proxy
statement/prospectus and any other relevant documents filed with the
SEC, as well as any amendments or supplements to those documents,
because they will contain important information about Petrohawk,
Mission and the acquisition. Investors and security holders may obtain
these documents free of charge at the SEC's website at www.sec.gov. In
addition, the documents filed with the SEC by Petrohawk may be
obtained free of charge from Petrohawk's website at www.petrohawk.com.
The documents filed with the SEC by Mission may be obtained free of
charge from Mission's website at www.mrcorp.com. Investors and
security holders are urged to read the joint proxy
statement/prospectus and the other relevant materials before making
any voting or investment decision with respect to the proposed
acquisition.
   Petrohawk, Mission and their respective executive officers and
directors may be deemed to be participants in the solicitation of
proxies from the stockholders of Petrohawk and Mission in favor of the
acquisition. Information about the executive officers and directors of
Petrohawk and their direct or indirect interests, by security holdings
or otherwise, in the acquisition is set forth in the joint proxy
statement/prospectus on Form S-4 as filed with the SEC by Petrohawk.
Information about the executive officers and directors of Mission and
their direct or indirect interests, by security holdings or otherwise,
in the acquisition is set forth in the proxy statement/prospectus
relating to the acquisition on Form S-4 as filed with the SEC by
Petrohawk. Information about the executive officers and directors of
Mission and their ownership of Mission common stock is set forth in
the Annual Report on Form 10 K/A that was filed by Mission with the
SEC on April 12, 2005.