BUCYRUS INTERNATIONAL, INC. SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

                                                                    Exhibit 10.6

                           BUCYRUS INTERNATIONAL, INC.
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

                           Effective October 20, 2006

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                           BUCYRUS INTERNATIONAL, INC.
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN
                           Effective October 20, 2006

I.    PURPOSE AND EFFECTIVE DATE.

      1.1.  Purpose.  The Bucyrus  International,  Inc.  Supplemental  Executive
            Retirement  Plan  (the  "Plan")  has  been  established  by  Bucyrus
            International,  Inc. to attract and retain  certain key employees by
            supplementing such key employees'  retirement income available under
            the Bucyrus International,  Inc. Salaried Employees' Retirement Plan
            (the "Qualified Plan"), which retirement income is otherwise limited
            by Sections 415 and 401(a)(17) of the Internal Revenue Code of 1986,
            as amended, and the regulations issued thereunder.

      1.2.  Effective  Date.  The Plan shall be  effective  October 20, 2006 and
            shall remain in effect until  terminated in accordance  with Section
            7.5.

II.   DEFINITIONS.

      When used in the Plan and initially  capitalized,  the following words and
      phrases shall have the meanings indicated:

      2.1.  "Account" means the bookkeeping  account established for purposes of
            accounting for the amount of a Participant's  Supplemental  Benefits
            Amount  determined  and credited in accordance  with Article IV each
            year, if any, as adjusted  periodically to reflect interest earnings
            on such amounts in accordance with Article V.

      2.2.  "Administrator"  means  the  Bucyrus  International,  Inc.  Benefits
            Committee  or  such  other  committee  as  may be  appointed  by the
            Committee to administer the Plan.

      2.3.  "Affiliate"  means  any  corporation,  partnership,  joint  venture,
            trust, association or other business enterprise which is a member of
            the same controlled group of  corporations,  trades or businesses as
            the Company, within the meaning of Code Section 414(b) or (c).

      2.4.  "Beneficiary"   means  the  person  or  entity   designated  by  the
            Participant to receive a Participant's Supplemental Benefits Amounts
            in the event of the Participant's death. If the Participant does not
            designate  a  Beneficiary,   or  if  the  Participant's   designated
            Beneficiary   predeceases   the   Participant,   the   Participant's
            beneficiary under the Qualified Plan shall be the Beneficiary.

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

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      2.6.  "Cash  Balance  Account"  shall  have the  meaning  set forth in the
            Qualified Plan.

      2.7.  "Cash Balance  Participant"  shall have the meaning set forth in the
            Qualified Plan.

      2.8.  "Code" means the  Internal  Revenue  Code of 1986,  as amended.  Any
            reference  to a  specific  provision  of the Code shall be deemed to
            include reference to any successor provision thereto.

      2.9.  "Committee" means the Compensation Committee of the Board.

      2.10. "Company"  means  Bucyrus  International,  Inc.  and  any  successor
            thereto.

      2.11. "Compensation"  shall have the  meaning  set forth in the  Qualified
            Plan.

      2.12. "Eligible  Employee" means a common-law U.S. employee of an Employer
            who (i) is a Cash Balance  Participant,  and (ii) who is employed in
            the position of a General  Manager,  Vice  President or above on the
            date the  allocation  described  in Section 4.1 is to be made to the
            individual's Account.

      2.13. "Employer"  means the  Company  and each  Affiliate  that,  with the
            consent of the Company, has elected to participate in the Plan.

      2.14. "ERISA" means the Employee  Retirement  Income Security Act of 1974,
            as amended.  Any reference to a specific provision of ERISA shall be
            deemed to include reference to any successor provision thereto.

      2.15. "Participant"   means  an  Eligible   Employee   who  has  become  a
            participant in the Plan in accordance with Section 3.1.

      2.16. "Plan" means the Bucyrus International,  Inc. Supplemental Executive
            Retirement  Plan,  as set forth  herein and as amended  from time to
            time.

      2.17. "Plan Year" means the  calendar  year.  The initial  Plan Year shall
            begin January 1, 2006.

      2.18. "Qualified  Plan" means the  Bucyrus  International,  Inc.  Salaried
            Employees' Retirement Plan, or any successor plan thereto.

      2.19. "Separation  from  Service"  means  the date on which a  Participant
            terminates  employment  with the Company and all of its  Affiliates,
            within the  meaning of Code  Section  409A.  A  Participant  has not
            incurred a Separation from Service if the Participant is absent from
            active  employment due to military  leave,  sick leave or other bona
            fide  leave of  absence  if the period of such leave does not exceed
            the greater of (1) six (6) months or (2) the period during which the
            Participant's  right to  reemployment by the Company or an Affiliate
            is provided either by statute or by contract.

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      2.20. "Supplemental  Benefit  Amounts"  means the amounts  credited to the
            Participant's Account in accordance with Article IV.

      2.21. "Valuation Date" means any date on which a Participant's  Account is
            valued,  which  shall be each  business  day of a Plan  Year  unless
            determined otherwise by the Administrator.

III.  PARTICIPATION.

      3.1.  Participation.  An employee shall automatically become a Participant
            in the  Plan on the date he or she is  hired  or  promoted  into the
            position of an Eligible Employee.  In addition,  any employee who is
            an  Eligible  Employee  on the  Effective  Date  of the  Plan  shall
            automatically  become  a  Participant  on  the  Effective  Date.  An
            Eligible  Employee  shall  cease  to  receive  Supplemental  Benefit
            Amounts,  although his or her Account  will  continue to be credited
            with interest  credits,  on the date the individual  ceases to be an
            Eligible Employee.

      3.2.  ERISA  Exemption.  It is the intent of the Company  that the Plan be
            exempt from Parts 2, 3 and 4 of  Subtitle B of Title I of ERISA,  as
            an unfunded plan that is maintained by the Company primarily for the
            purpose of  providing  deferred  compensation  for a select group of
            management and highly compensated employees (the "ERISA Exemption").
            Notwithstanding  anything  to the  contrary in Section 3.1 or in any
            other  provision  of the  Plan,  the  Committee  may,  in  its  sole
            discretion,  exclude any one or more employees  from  eligibility to
            participate  or  from   participation  in  the  Plan,   exclude  any
            Participant  from continued  participation in the Plan, and take any
            further action permissible under Code Section 409A that it considers
            necessary or appropriate if the Committee  reasonably  determines in
            good faith that such  exclusion  or further  action is  necessary in
            order for the Plan to qualify  for, or to  continue to qualify  for,
            the ERISA Exemption.

IV.   SUPPLEMENTAL BENEFIT AMOUNTS.

      4.1.  Computation of Supplemental  Benefit Amounts. A Participant shall be
            entitled to Supplemental  Benefit Amounts for each Plan Year that he
            or she is an Eligible  Employee.  Such  Supplemental  Benefit Amount
            shall be equal to the excess, if any, of:

                  (i)   the amount the Eligible  Employee  otherwise  would have
                        been  entitled  to  have  credited  to his  or her  Cash
                        Balance  Account as a pay credit for the Plan Year under
                        the  Qualified  Plan  if  such  benefit  was  calculated
                        without regard to Code Sections 401(a)(17) and 415, over

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                  (ii)  the amount which is credited to the Eligible  Employee's
                        Cash Balance  Account as a pay credit for such Plan Year
                        under the Qualified Plan.

      4.2.  Vesting.  A Participant's  Account shall vest in accordance with the
            same vesting schedule that applies to the Participants' Cash Balance
            Account  under the Qualified  Plan.  If a Participant  who Separates
            from Service is not vested in his or her Account, such Account shall
            be  forfeited  and the  Participant  shall  not be  entitled  to any
            payments hereunder.

      4.3.  Crediting of Supplemental  Benefit Amounts. The Supplemental Benefit
            Amount  computed  in  Section  4.1 above for each Plan Year shall be
            credited to the Participant's Account as of the last day of the Plan
            Year.  Notwithstanding the foregoing,  if the Participant  Separates
            from Service during the Plan Year, the  Supplemental  Benefit Amount
            shall be  credited  as of the last  day of the  month in which  such
            Separation from Service occurs.

V.    ACCOUNTS AND INVESTMENTS.

      5.1.  Valuation of Accounts.  The Administrator shall establish an Account
            for each  Participant  who has  been  credited  with a  Supplemental
            Benefit Amount.  Such Account shall be credited with a Participant's
            Supplemental Benefit Amount as set forth in Sections 4.3. As of each
            Valuation Date, the Participants'  Accounts shall be adjusted upward
            or downward to reflect:

            (a)   the interest earnings to be credited as of such Valuation Date
                  pursuant to Section 5.2 below, and

            (b)   the amount of distributions, if any, to be debited as of that
                  Valuation Date under Article VI.

      5.2.  Interest Credits. Accounts shall be credited with interest credits
            on the last day of each calendar month. Such interest credit shall