Document:

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                                                                    EXHIBIT 4.12

                                                                  EXECUTION COPY

                       FIFTH AMENDMENT TO CREDIT AGREEMENT

         This Fifth Amendment to Credit Agreement (this "Fifth Amendment") is
made as of this 27th day of February, 2004 by and among SEMCO ENERGY, INC., a
Michigan corporation (the "Company"), STANDARD FEDERAL BANK N.A. ("Standard
Federal") and the other banks signatory hereto and Standard Federal, as agent
for the Banks (in such capacity, "Agent").

                                    RECITALS

         A.       Company, Agent and the Banks entered into that certain Credit
Agreement dated as of June 25, 2002 under which the Banks extended (or committed
to extend) credit to the Company, as set forth therein, as amended by that
certain First Amendment to Credit Agreement (the "First Amendment") dated May
21, 2003, that certain Second Amendment to Credit Agreement (the "Second
Amendment") dated September 30, 2003, that certain Third Amendment to Credit
Agreement (the "Third Amendment") dated October 15, 2003, and that certain
Fourth Amendment dated December 12, 2003 (as so amended, the "Credit Agreement";
capitalized terms not otherwise defined herein shall have the meanings ascribed
thereto in the Credit Agreement).

         B.       Company has requested that Agent and the requisite Banks
increase the Letter of Credit Commitment Amount from Five Million Dollars
($5,000,000) to Ten Million Dollars ($10,000,000), and amend certain terms and
provisions of the Credit Agreement and Agent and the requisite Banks are willing
to do so, but only on the terms and conditions set forth in this Fifth
Amendment.

         NOW, THEREFORE, Company, Agent and Banks agree:

1.       Section 1.1 of the Credit Agreement shall be amended by deleting the
         definition of "Letter of Credit Commitment Amount" and inserting the
         following in its place:

                  "Letter of Credit Commitment Amount shall mean $10,000,000."

2.       Section 2.2.3 of the Credit Agreement shall be amended by deleting
         subsection (b)(i) thereof and inserting the following in its place:

                  "(i) the aggregate Stated Amount of all Letters of Credit
                  issued hereunder shall not at any time exceed the Letter of
                  Credit Commitment Amount and"

3        Section 10.10 is deleted in its entirety and the following is inserted
         in its place:

                  "10.10 Restricted Payments. Not, and not permit any Subsidiary
                  to, (a) make any distribution to any of its shareholders, (b)
                  purchase or redeem any of its capital stock or other equity
                  interests or any warrants, options or other rights in respect
                  thereof, (c) issue any Disqualified Stock, or (d) set aside
                  funds for any of the foregoing. Notwithstanding the foregoing,
                  (i) any Subsidiary may

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                  pay dividends or make other distributions to the Company or to
                  a Wholly-Owned Subsidiary; (ii) so long as no Event of Default
                  or Unmatured Event of Default exists or would result
                  therefrom, the Company may make, pay, declare or authorize any
                  dividend, payment or other distribution in respect of any
                  class of its capital stock or any dividend, payment or
                  distribution in connection with the redemption, purchase,
                  retirement or other acquisition, directly or indirectly, of
                  any shares of its capital stock, to the extent in each case
                  payable solely in shares of capital stock of the Company, and
                  (iii) the Company may make, pay, declare or authorize any
                  dividend, payment or other distribution in respect of any
                  class of its capital stock or any dividend, payment or
                  distribution in connection with the redemption, purchase,
                  retirement or other acquisition, directly or indirectly, of
                  any shares of its capital stock, subject to the satisfaction
                  of each of the following conditions: (x) the aggregate amount
                  of such dividends, payments or other distributions covered by
                  this clause (iii) made during the period from and after March
                  31, 2002 to and including the date of the making of the
                  dividend, payment or other distribution in question, shall not
                  exceed the sum of $17,693,000 plus 100% of Consolidated Net
                  Income for such period, such Consolidated Net Income to be
                  calculated for this purpose by adding back an amount equal to
                  65% of the Refinancing Premium to the extent deducted from the
                  Consolidated Net Income and to be computed on a cumulative
                  basis for said entire period (or if such Consolidated Net
                  Income is a deficit figure, then minus 100% of such deficit)
                  and (y) immediately before and after giving effect to such
                  dividend, payment or other distribution, no Event of Default
                  or Unmatured Event of Default shall exist or shall have
                  occurred and be continuing and the representations and
                  warranties contained in Section 9 and in the other Loan
                  Documents shall be true and correct on and as of the date
                  thereof (both before and after giving effect to such dividend,
                  payment or other distribution) as if made on the date of such
                  dividend, payment or other distribution. Upon the occurrence
                  of the Reclassification Event, dividend payments on the Junior
                  Capital shall remain subject to the provisions of this Section
                  10.10."

4.       This Fifth Amendment shall become effective according to the terms
         hereof and as of such date (the "Fifth Amendment Effective Date") that
         the Company shall have satisfied the following conditions:

                  (a)      Agent shall have received:

                           (i)      counterpart originals of this Fifth
                  Amendment, in each case duly executed and delivered by Company
                  and the requisite Banks, in form satisfactory to Agent and the
                  Banks; and

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                           (ii)     such other documents as Agent may reasonably
                  request.

                  (b)      No Unmatured Event of Default or Event of Default
         shall have occurred and be continuing or shall result from the
         execution and delivery of this Fifth Amendment.

                  (c)      If the Fifth Amendment Effective Date shall not have
         occurred on or before February 27, 2004, this Fifth Amendment shall not
         become effective and the offer by the Agent and the Banks to amend the
         Credit Agreement on the terms set forth herein shall be deemed
         withdrawn.

5.       The Company for itself and each of the Subsidiaries hereby represents
         and warrants that, after giving effect to the amendments contained
         herein, (a) execution and delivery of this Fifth Amendment, and the
         performance by the Company of its obligations under the Credit
         Agreement as amended hereby are within such undersigned's corporate
         powers, have been duly authorized, are not in contravention of law or
         the terms of its articles of incorporation, bylaws or any other
         organizational documents of the parties thereto, as applicable, and
         except as have been previously obtained, do not require the consent or
         approval, material to the amendments contemplated in this Fifth
         Amendment or Credit Agreement, as amended hereby, of any governmental
         body, agency or authority, and this Fifth Amendment and the Credit
         Agreement, as amended hereby, will constitute the valid and binding
         obligations of such undersigned parties, enforceable in accordance with
         their respective terms, except as enforcement thereof may be limited by
         applicable bankruptcy, reorganization, insolvency, moratorium, ERISA or
         similar laws affecting the enforcement of creditors' rights generally
         and by general principles of equity (whether enforcement is sought in a
         proceeding in equity or at law), and (b) the representations and
         warranties contained in Section 9 of the Credit Agreement are true and
         correct on and as of the date hereof, except to the extent such
         representations and warranties speak only as of another date certain.

6.       Except as specifically set forth herein, this Fifth Amendment shall not
         be deemed to amend or alter in any respect the terms and conditions of
         the Credit Agreement, any of the Notes issued thereunder or any of the
         Loan Documents, or to constitute a waiver by the Banks or Agent of any
         right or remedy under or a consent to any transaction not meeting the
         terms and conditions of the Credit Agreement, any of the Notes issued
         thereunder or any of the other Loan Documents.

7.       Unless otherwise defined to the contrary herein, all capitalized terms
         used in this Fifth Amendment shall have the meaning set forth in the
         Credit Agreement, as amended.

8.       This Fifth Amendment shall be construed in accordance with and governed
         by the laws of the State of Michigan.

9.       Any references in the Loan Documents to the Credit Agreement shall be
         deemed a reference to the Credit Agreement as amended by the First
         Amendment and this Fifth Amendment.

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                    [SIGNATURES FOLLOW ON SUCCEEDING PAGES]

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         WITNESS the due execution hereof as of the day and year first above
written.

                                    SEMCO ENERGY, INC.

                                    By /s/ John E. Schneider
                                       -----------------------------
                                    Title Senior Vice President and
                                          Chief Financial Officer

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                                    STANDARD FEDERAL BANK N.A., A NATIONAL
                                    BANKING ASSOCIATION, as Agent

                                       /s/ Gregory E. Castle
                                    By Gregory E. Castle
                                    Title First Vice President

                                    STANDARD FEDERAL BANK N.A., A NATIONAL
                                    BANKING ASSOCIATION, as Issuing Bank, as
                                    Swing Line Bank and as a Bank

                                       /s/ Gregory E. Castle
                                    By Gregory E. Castle
                                    Title First Vice President

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                                    KEYBANK NATIONAL ASSOCIATION, as
                                    Syndication Agent and as a Bank

                                    By /s/ Sherrie I. Manson
                                       -----------------------------
                                       Sherrie I. Manson
                                    Title Vice President

                    SIGNATURE PAGE TO SEMCO FIFTH AMENDMENT
                                    (528954)

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                                    U.S. BANK, N.A., as Documentation Agent and
                                    as a Bank

                                    By /s/ Jeffrey J. Janza
                                       -----------------------------
                                    Title VICE PRESIDENT

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                                    NATIONAL CITY BANK OF MICHIGAN /
                                    ILLINOIS, as Documentation Agent and as
                                    a Bank

                                    By /s/ Kenneth R. Ehrhardt
                                       -----------------------------
                                    Title Senior Vice President

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                                    THE HUNTINGTON NATIONAL BANK, as a
                                    Bank

                                    By /s/ Kevin D. Szachta
                                       -----------------------------
                                       Kevin D. Szachta
                                    Title Vice President

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                                    FIFTH THIRD BANK, EASTERN MICHIGAN,
                                    as a Bank

                                    By /s/ ANDRE A. NAZARETH
                                       -----------------------------
                                       ANDRE A. NAZARETH
                                    Title VICE PRESIDENT

                                       11<PAGE>
                                                                    Exhibit 10.5

                            NATURAL RESOURCE PARTNERS
                            LONG-TERM INCENTIVE PLAN
                            (AS AMENDED AND RESTATED)

SECTION 1. Purpose of the Plan.

         The Natural Resource Partners Long-Term Incentive Plan (the "Plan") is
intended to promote the interests of Natural Resource Partners L.P., a Delaware
limited partnership (the "Partnership"), by providing to employees and directors
of GP Natural Resource Partners LLC (the "Company") and its Affiliates who
perform services for the Partnership incentive compensation cash awards for
superior performance that are based on Units. The Plan is also contemplated to
enhance the ability of the Company and its Affiliates to attract and retain the
services of individuals who are essential for the growth and profitability of
the Partnership and to encourage them to devote their best efforts to the
business of the Partnership, thereby advancing the interests of the Partnership
and its partners.

SECTION 2. Definitions.

         As used in the Plan, the following terms shall have the meanings set
forth below:

         "Affiliate" means, with respect to any Person, any other Person that
directly or indirectly through one or more intermediaries controls, is
controlled by or is under common control with, the Person in question. As used
herein, the term "control" means the possession, direct or indirect, of the
power to direct or cause the direction of the management and policies of a
Person, whether through ownership of voting securities, by contract or
otherwise.

         "Award" means a Phantom Unit granted under the Plan.

         "Board" means the Board of Directors of the Company.

         "Change in Control" shall be deemed to have occurred upon the
occurrence of one or more of the following events: (i) any sale, lease, exchange
or other transfer (in one or a series of related transactions) of all or
substantially all of the assets of the Partnership, NRP (GP) LP or the Company
to any Person, other than the Partnership, NRP (GP) LP, the Company or any of
their Affiliates, or (ii) any merger, reorganization, consolidation or other
transaction pursuant to which more than 50% of the combined voting power of the
outstanding equity interests in either NRP (GP) LP or the Company ceases to be
owned by the Persons who own such interests, respectively, as of the effective
date of the initial public offering of Units.

         "Committee" means the Compensation Committee of the Board or such other
committee of the Board appointed by the Board to administer the Plan.

         "Director" means a member of the Board or the Board of Directors or
Board of Managers of an Affiliate who is not an Employee.

         "Employee" means any employee of the Company or an Affiliate, as
determined by the Committee.

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         "Fair Market Value" means the closing sales price of a Unit on the
applicable date (or if there is no trading in the Units on such date, on the
next preceding date on which there was trading) as reported in The Wall Street
Journal (or other reporting service approved by the Committee). In the event (1)
there is no sale of Units on the New York Stock Exchange or any other national
securities exchange on which the Units are listed for more than 10 days
preceding such date or (2) the Units are not publicly traded at the time a
determination of fair market value is required to be made hereunder, the
determination of fair market value shall be made in good faith by the Committee.

          "Participant" means any Employee or Director granted an Award under
the Plan.

         "Partnership Agreement" means the Amended and Restated Agreement of
Limited Partnership of Natural Resource Partners L.P.

         "Person" means an individual or a corporation, limited liability
company, partnership, joint venture, trust, unincorporated organization,
association, government agency or political subdivision thereof or other entity.

         "Phantom Unit" means a phantom (notional) Unit granted under the Plan
which upon vesting entitles the Participant to receive an amount of cash equal
to the Fair Market Value of a Unit.

         "Restricted Period" means the period established by the Committee with
respect to an Award during which the Award remains subject to forfeiture (is not
vested) and is not payable to the Participant.

         "Unit" means a Common Unit of the Partnership.

SECTION 3. Administration.

         The Committee shall administer the Plan. A majority of the Committee
shall constitute a quorum, and the acts of the members of the Committee who are
present at any meeting thereof at which a quorum is present, or acts unanimously
approved by the members of the Committee in writing, shall be the acts of the
Committee. Subject to the following and any applicable law, the Committee, in
its sole discretion, may delegate any or all of its powers and duties under the
Plan (provided the Chief Executive Officer is a member of the Board), including
the power to grant Awards under the Plan, to the Chief Executive Officer of the
Company, subject to such limitations on such delegated powers and duties as the
Committee may impose, if any. Upon any such delegation all references in the
Plan to the "Committee", other than in Section 6, shall be deemed to include the
Chief Executive Officer; provided, however, that such delegation shall not limit
the Chief Executive Officer's right to receive Awards under the Plan.
Notwithstanding the foregoing, the Chief Executive Officer may not grant Awards
to, or take any action with respect to any Award previously granted to, a person
who is an executive officer or a member of the Board. Subject to the terms of
the Plan and applicable law, and in addition to other express powers and
authorizations conferred on the Committee by the Plan, the Committee shall have
full power and authority to: (i) designate Participants; (ii) determine the
number of Units to be covered by Awards; (iii) determine the terms and
conditions of any Award; (iv) determine whether, to what extent, and under what
circumstances Awards may be settled, exercised, canceled, or forfeited; (v)
interpret and administer the Plan and any instrument or agreement relating to an
Award made under the Plan; (vi) establish,

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amend, suspend, or waive such rules and regulations and appoint such agents as
it shall deem appropriate for the proper administration of the Plan; and (vii)
make any other determination and take any other action that the Committee deems
necessary or desirable for the administration of the Plan. Unless otherwise
expressly provided in the Plan, all designations, determinations,
interpretations, and other decisions under or with respect to the Plan or any
Award shall be within the sole discretion of the Committee, may be made at any
time and shall be final, conclusive, and binding upon all Persons, including the
Company, the Partnership, any Affiliate, any Participant, and any beneficiary of
any Award.

SECTION 4. Eligibility.

         Any Employee or Director who performs services for the Partnership
shall be eligible to be designated a Participant and receive an Award under the
Plan.

SECTION 5. Awards.

         (a)      Phantom Units. The Committee shall have the authority to
determine the Employees and Directors to whom Phantom Units shall be granted,
the number of Phantom Units to be granted to each such Participant, the
Restricted Period, the conditions under which the Phantom Units may become
vested or forfeited, which may include, without limitation, the accelerated
vesting upon the achievement of specified performance goals, and such other
terms and conditions as the Committee may establish with respect to such Awards.

                  (i)      Forfeiture. Except as otherwise provided in the terms
         of the Phantom Units grant, upon termination of a Participant's
         employment with the Company and its Affiliates or membership on the
         Board, whichever is applicable, for any reason during the applicable
         Restricted Period, all Phantom Units shall be forfeited by the
         Participant unless otherwise provided in a written employment agreement
         between the Participant and the Company or its Affiliates. The
         Committee may, in its discretion, waive in whole or in part such
         forfeiture with respect to a Participant's Phantom Units.

                  (ii)     Lapse of Restrictions. Upon or as soon as reasonably
         practical following the vesting of each Phantom Unit, the Participant
         shall be entitled to receive from the Company an amount of cash equal
         to the Fair Market Value of a Unit.

         (b)      General.

                  (i)      Awards May Be Granted Separately or Together. Awards
         may, in the discretion of the Committee, be granted either alone or in
         addition to, in tandem with, or in substitution for any other Award
         granted under the Plan or any award granted under any other plan of the
         Company or any Affiliate. Awards granted in addition to or in tandem
         with other Awards or awards granted under any other plan of the Company
         or any Affiliate may be granted either at the same time as or at a
         different time from the grant of such other Awards or awards.

                  (ii)     Limits on Transfer of Awards.

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                           (A)      Except as provided in (B) below, no Award
                  and no right under any such Award may be assigned, alienated,
                  pledged, attached, sold or otherwise transferred or encumbered
                  by a Participant and any such purported assignment,
                  alienation, pledge, attachment, sale, transfer or encumbrance
                  shall be void and unenforceable against the Company or any
                  Affiliate.

                           (B)      Participants may transfer Awards by will and
                  the laws of descent and distribution.

                  (iii)    Term of Awards. The term of each Award shall be for
         such period as may be determined by the Committee.

                  (iv)     Consideration for Grants. Awards may be granted for
         such consideration, including services or such minimal consideration as
         may be required by law, as the Committee determines.

                  (v)      Change in Control. Upon a Change in Control or such
         period prior thereto as may be established by the Committee, all Awards
         shall automatically vest and become payable in full. In this regard,
         all Restricted Periods shall terminate and all performance criteria, if
         any, shall be deemed to have been achieved at the maximum level.

         (c)      Adjustments. In the event that the Committee determines that
any distribution (whether in the form of cash, Units, other securities, or other
property), recapitalization, split, reverse split, reorganization, merger,
consolidation, split-up, spin-off, combination, repurchase, or exchange of Units
or other securities of the Partnership, issuance of warrants or other rights to
purchase Units or other securities of the Partnership, or other similar
transaction or event affects the Units such that an adjustment is determined by
the Committee to be appropriate in order to prevent dilution or enlargement of
the benefits or potential benefits intended to be made available under the Plan,
then the Committee shall, in such manner as it may deem equitable, adjust any or
all of (i) the number and type of Units (or other securities or property) with
respect to which Awards may be granted, (ii) the number and type of Units (or
other securities or property) subject to outstanding Awards, and (iii) if deemed
appropriate, make provision for a cash payment to the holder of an outstanding
Award; provided, that the number of Units subject to any Award shall always be a
whole number.

SECTION 6. Amendment and Termination.

         Except to the extent prohibited by applicable law:

         (a)      Amendments to the Plan. Except as required by the rules of the
principal securities exchange on which the Units are traded and subject to
Section 6(b) below, the Board or the Committee may amend, alter, suspend,
discontinue, or terminate the Plan in any manner, including increasing the
number of Units available for Awards under the Plan, without the consent of any
partner, Participant, other holder or beneficiary of an Award, or other Person.

         (b)      Amendments to Awards. Subject to Section 6(a), the Committee
may waive any conditions or rights under, amend any terms of, or alter any Award
theretofore granted, provided no

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change, other than pursuant to Section 6(c), in any Award shall materially
reduce the benefit to a Participant without the consent of such Participant.

         (c)      Adjustment of Awards Upon the Occurrence of Certain Unusual or
Nonrecurring Events. The Committee is hereby authorized to make adjustments in
the terms and conditions of, and the criteria included in, Awards in recognition
of unusual or nonrecurring events (including, without limitation, the events
described in Section 5(c) of the Plan) affecting the Partnership or the
financial statements of the Partnership, or of changes in applicable laws,
regulations, or accounting principles, whenever the Committee determines that
such adjustments are appropriate in order to prevent dilution or enlargement of
the benefits or potential benefits intended to be made available under the Plan.

SECTION 7. General Provisions.

         (a)      No Rights to Award. No Person shall have any claim to be
granted any Award under the Plan, and there is no obligation for uniformity of
treatment of Participants. The terms and conditions of Awards need not be the
same with respect to each recipient.

         (b)      Withholding. The Company or any Affiliate is authorized to
withhold from any Award, from any payment due under any Award or from any
compensation or other amount owing to a Participant the amount of any applicable
taxes payable in respect of the grant of an Award, the lapse of restrictions
thereon, or any payment under an Award or under the Plan and to take such other
action as may be necessary in the opinion of the Company to satisfy its
withholding obligations for the payment of such taxes.

         (c)      No Right to Employment. The grant of an Award shall not be
construed as giving a Participant the right to be retained in the employ of the
Company or any Affiliate or to remain on the Board, as applicable. Further, the
Company or an Affiliate may at any time dismiss a Participant from employment,
free from any liability or any claim under the Plan, unless otherwise expressly
provided in the Plan or in any Award agreement.

         (d)      Governing Law. The validity, construction, and effect of the
Plan and any rules and regulations relating to the Plan shall be determined in
accordance with the laws of the State of Delaware law without regard to its
conflict of laws principles.

         (e)      Severability. If any provision of the Plan or any award is or
becomes or is deemed to be invalid, illegal, or unenforceable in any
jurisdiction or as to any Person or Award, or would disqualify the Plan or any
award under any law deemed applicable by the Committee, such provision shall be
construed or deemed amended to conform to the applicable laws, or if it cannot
be construed or deemed amended without, in the determination of the Committee,
materially altering the intent of the Plan or the Award, such provision shall be
stricken as to such jurisdiction, person or award and the remainder of the Plan
and any such Award shall remain in full force and effect.

         (f)      Other Laws. The Committee may refuse to pay any cash under an
Award if, in its sole discretion, it determines that the payment might violate
any applicable law or regulation or the rules of the principal securities
exchange on which the Units are then traded.

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         (g)      No Trust or Fund Created. Neither the Plan nor any Award shall
create or be construed to create a trust or separate fund of any kind or a
fiduciary relationship between the Company or any participating Affiliate and a
Participant or any other Person. To the extent that any Person acquires a right
to receive payments from the Company or any participating Affiliate pursuant to
an award, such right shall be no greater than the right of any general unsecured
creditor of the Company or any participating Affiliate.

         (h)      Headings. Headings are given to the Sections and subsections
of the Plan solely as a convenience to facilitate reference. Such headings shall
not be deemed in any way material or relevant to the construction or
interpretation of the Plan or any provision thereof.

         (i)      Facility Payment. Any amounts payable hereunder to any person
under legal disability or who, in the judgment of the Committee, is unable to
properly manage his financial affairs, may be paid to the legal representative
of such person, or may be applied for the benefit of such person in any manner
which the Committee may select, and the Company shall be relieved of any further
liability for payment of such amounts.

         (j)      Gender and Number. Words in the masculine gender shall include
the feminine gender, the plural shall include the singular and the singular
shall include the plural.

SECTION 8. Term of the Plan.

         This Plan amendment and restatement shall be effective on the date of
its approval by the Board and shall continue until the date terminated by the
Board. However, unless otherwise expressly provided in the Plan or in an
applicable Award Agreement, any Award granted prior to such termination, and the
authority of the Board or the Committee to amend, alter, adjust, suspend,
discontinue, or terminate any such Award or to waive any conditions or rights
under such Award, shall extend beyond such termination date.

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