FIRST AMENDMENT TO FIRST AMENDED AND RESTATED NOTE PURCHASE AGREEMENT

                               FIRST AMENDMENT TO
               FIRST AMENDED AND RESTATED NOTE PURCHASE AGREEMENT

      This FIRST AMENDMENT TO FIRST AMENDED AND RESTATED NOTE PURCHASE
AGREEMENT, dated as of January 31, 2006 (this "Amendment"), is made by and among
by and among Aurora Antrim North, LLC, a Michigan limited liability company (the
"Issuer"); Aurora Energy, Ltd., a Nevada corporation ("Aurora"); TCW Energy Fund
X - NL, L.P., a California limited partnership ("Fund X - NL"); TCW Energy Fund
XB - NL, L.P., a California limited partnership ("Fund XB - NL"); TCW Energy
Fund XC - NL, L.P., a California limited partnership ("Fund XC - NL"); TCW
Energy Fund XD - NL, L.P., a California limited partnership ("Fund XD - NL");
TCW Asset Management Company ("Tamco"), a California corporation, as Investment
Manager under the Amended and Restated Investment Management and Custody
Agreement dated as of December 3, 2003 among Ensign Peak Advisors, Inc. and
others; Tamco as Investment Manager under the Amended and Restated Investment
Management and Custody Agreement dated as of March 18, 2004 among ING Life
Insurance and Annuity Company and others; Tamco as Investment Manager under the
Amended and Restated Investment Management and Custody Agreement dated as of
December 11, 2003, among Harry L. Bradley, Jr. Partition Trust and others;
Tamco, as Investment Manager under the Investment Management Agreement dated
June 13, 2005 among The Ford Foundation and others (Tamco in the capacities
designated above, Fund X - NL, Fund XB - NL, Fund XC - NL and Fund XD - NL are
hereinafter collectively referred to as the "Purchasers," each a "Purchaser");
Tamco as Administrative Agent (together with its successors in such capacity,
the "Administrative Agent"); and Tamco as Collateral Agent (together with its
successors in such capacity, the "Collateral Agent").

                                    RECITALS

      WHEREAS, the Issuer and Aurora have entered into that certain First
Amended and Restated Note Purchase Agreement (as amended, modified or
supplemented from time to time, the "First Amended and Restated Note Purchase
Agreement") with the Purchasers, Administrative Agent and Collateral Agent.

      WHEREAS, the Issuer desires to enter into that certain Senior Revolving
Credit Agreement, dated as of even date herewith, by and among the Issuer, BNP
Paribas, as Administrative Agent and the other Senior Revolving Lenders party
thereto.

      WHEREAS, the Issuer, Aurora, the Purchasers, Administrative Agent and
Collateral Agent desire to amend the First Amended and Restated Note Purchase
Agreement to the extent set forth herein.

      NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree to amend and modify the First
Amended and Restated Note Purchase Agreement, subject to the satisfaction of the
conditions precedent set forth in Section 3 hereof, as follows:

<PAGE>

      Section 1. Defined Terms. Capitalized terms used but not defined in this
Amendment shall have the meanings assigned to such terms in the First Amended
and Restated Note Purchase Agreement, as amended by this Amendment.

      Section 2. Amendments.

            2.01 Section 1.1 of the First Amended and Restated Note Purchase
Agreement is hereby amended by inserting the following definition:

            "Permitted Senior Bank Facility" means that certain Senior Revolving
      Credit Agreement, dated as of even date herewith, by and among the Issuer,
      BNP Paribas, as Administrative Agent and the financial institutions listed
      therein from time to time as Senior Revolving Lenders (as defined
      therein), as from time to time renewed, extended, amended, supplemented,
      or restated, and any agreements representing the refinancing, replacement,
      or substitution in whole or in part of the revolving credit loans and
      letter of credit liabilities made or incurred under such Revolving Credit
      Agreement."

            2.02 Section 1.1 of the First Amended and Restated Note Purchase
Agreement is hereby amended by deleting the definition of "Permitted
Encumbrances" in its entirety, and replacing it with the following paragraph:

            "Permitted Encumbrances" means

            (a) Liens imposed by law for taxes, assessments or other
governmental charges or levies that are not at the time delinquent or are being
contested in compliance with Section 5.1(i);

            (b) carriers', warehousemen's, mechanics', materialmen's,
repairmen's and other like Liens imposed by law, arising in the ordinary course
of business and securing obligations that are not overdue or are being contested
in compliance with Section 5.1(i);

            (c) pledges and deposits made in the ordinary course of business in
compliance with workers' compensation, unemployment insurance and other social
security laws or regulations;

            (d) deposits to secure the performance of tenders, bids, trade
contracts, leases, statutory obligations, surety and appeal bonds, performance
bonds and other obligations of a like nature, in each case in the ordinary
course of business;

            (e) irregularities in title, boundaries, or other survey defects,
easements, leases, restrictions, servitudes, permits, zoning restrictions,
rights-of-way, conditions, covenants, and rights of others in any property of
the Issuer and its Subsidiaries for streets, roads, bridges, pipes, pipelines,
railroads, electric transmission and distribution lines, telegraph and telephone
lines, flood control, water rights, rights of others with respect to navigable
waters, sewage and drainage rights existing as of the Closing Date or granted by
the Issuer or its Subsidiaries in the ordinary course of business and other
similar charges or encumbrances which do not secure the payment of money and
otherwise do not materially interfere with the occupation, use and enjoyment by
the Issuer or its Subsidiaries of any of the Property in the normal course of
business or materially impair the value thereof;


                                       2
<PAGE>

            (f) licenses granted in the ordinary course of business and leases
of Property of the Issuer and its Subsidiaries that is not material to the
business and operations of the Issuer and its Subsidiaries;

            (g) security interests arising by operation of law solely under
Article 2 of the UCC to the extent and so long as the "debtor" with respect to
such security interests does not have or does not lawfully obtain possession of
the goods subject thereto;

            (h) any Lien or privilege vested in any lessor, licensor or
permittor for rent to become due or for other obligations or acts to be
performed, the payment of which rent or the performance of which other
obligations or acts is required under leases, subleases, licenses or permits;

            (i) any obligations or duties affecting any of the Property to any
municipality or public authority with respect to any franchise, grant, license
or permit which do not materially impair the use of such Property for the
purposes for which it is held; and

            (j) Liens securing the Permitted Senior Bank Facility which do not
encumber any equity interest in the Issuer or any Overriding Royalty Interest.

            provided that other than as described in clause (j) above, the term
"Permitted Encumbrances" shall not include any Lien securing Funded
Indebtedness.

            2.03 Section 2.7 of the First Amended and Restated Note Purchase
Agreement is hereby amended and replaced in its entirety as follows:

                  "As additional consideration for the Notes, Issuer and Aurora
shall, pursuant to an ORRI Conveyance executed, delivered and recorded
concurrently with the later of the Closing or Issuer's or Aurora's acquisition
of title, assign to ORRI Assignee an overriding royalty interest (the
"Overriding Royalty Interest") in the Lands covered or included in the Initial
Engineering Report or any subsequent Engineering Report and all other properties
in the Project Area drilled or otherwise developed by Issuer or Aurora on or
before the later of the Maturity Date or the repayment in full of the Notes and
the Note Obligations (excluding those Note Obligations arising under the
Overriding Royalty Interest). The Overriding Royalty Interest will have a
royalty share of four percent (4%) proportionally reduced to Issuer's or
Aurora's (i) working interest if the burdened interest of Issuer or Au