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Exhibit 10.4
 SHARE PURCHASE AGREEMENT
 This Share Purchase Agreement Agreement th Effective Date Willbros Acquisition Canada
Limited Purchaser AMEC
Inc. AMEC AMEC Americas Sellers Seller
 RECITALS
 Midwest Business
  Parties
  ARTICLE I
DEFINITIONS
 Defined Terms.
 Accounts Payable
 Adjustment Statement
 Affiliate control controlled by under
common control with
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Agreement
 AMEC
 AMEC Americas
 Applicable Privacy Laws
 Bureau
 Business
 Centra Gas Project
 Claim
 Closing
 Closing Balance Sheet
 Closing Date
 Closing Date Adjusting Payments
 Closing Purchase Price
 Company Contracts
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Company Employee Benefit Plans
 Company Permits
 Competition Act Approval
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Commissioner
 Current Assets
 Current Liabilities
 Debt Load Adjustment
 Deposit
 Disclosed Personal Information
 Disclosure Schedule Disclosure Schedule Disclosure Schedule
 Dollars $
 Effective Date
 Ellis Drive Property
 Environmental Law
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Environmental Reports
 Estimated Closing Balance Sheet
 FCPA
 GAAP
 Golder Associates Work Plan
 Golder Phase I
 Golder Phase II
 Governmental Authority
 Hazardous Material
 Indemnified Person
 Indemnifying Party
 Independent Accounting Firm
 Intellectual Property Rights
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Inventory
 Knowledge
 Lien
 Material Adverse Effect
 Material Claims
 MGCL Shares
 Midwest
 Midwest Group
  -6-




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Midwest Group Financial Statements
 MPRI Shares
 Northern Territories
 Organizational Documents
 Other Liabilities Adjustment
 Parties
 Person
 Personal Information
 Post Closing Date Adjusting Payments
 Prohibited Property
 Purchase Price
 Purchaser
 Purchaser Representative
 Related persons
 Resolution Period
  -7-




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Responsible Officer
 Sellers Seller
 Seller Representative
 Shares
 Subsidiaries MGCL MPRI
 Tangible Personal Property
 Target Working Capital
 Target Working Capital Adjustment
 Tax Act Income Tax Act th
 Tax Returns
 Taxes
 Third-Party Consent
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Threshold Amount
 Western Canada
 Working Capital
 Other Definitional Provisions.
   this Agreement herein hereby hereunder hereof this Article this Section this
subsection or including
  ARTICLE II
PURCHASE AND SALE
 Purchase and Sale.
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Deposit.
 Deposit
  Purchase Price; Adjustment; Dispute.
 Closing Purchase
Price
  Closing Date Adjusting Payments Estimated Closing Balance Sheet Closing Date Adjusting Payments
 Debt Load Adjustment
 Target Working Capital Adjustment
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Other Liabilities Adjustment
 Closing Balance Sheet Closing
Balance Sheet
 Dispute Resolution. Resolution
Period Independent Accounting Firm
  -11-




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Post Closing Date Adjusting Payments Post Closing Date Adjusting Payments
 ARTICLE III
CLOSING
 Closing. Closing Date
 Closing Obligations.
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ARTICLE IV
REPRESENTATIONS AND WARRANTIES
 Representations and Warranties of Sellers.
 Organization of Sellers.
   Authority.
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Validity and Binding Effect.
 Noncontravention. Disclosure Schedule
 Consents and Approvals. Disclosure Schedule
 Title to the Shares.
 Organization of Midwest and the Subsidiaries.
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Investments. Disclosure Schedule
 Assets. Disclosure Schedule
 Financial Statements. Midwest Group Financial Statements
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Disclosure Schedule
 Capital Structure.
  MGCL Shares
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MPRI Shares
 Indebtedness and Guarantees. Disclosure
Schedule Disclosure Schedule vice versa
 Absence of Certain Changes or Events. Disclosure Schedule
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Commitments.
 Compliance with Laws. Disclosure Schedule Disclosure Schedule
 Permits. Disclosure Schedule Disclosure Schedule
 Litigation. Disclosure Schedule
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No Restrictions. Disclosure Schedule
 Environmental Matters. Disclosure Schedule
       Intellectual Property. Disclosure Schedule Disclosure Schedule
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Insurance. Disclosure Schedule Disclosure Schedule
 Contracts and Agreements. Disclosure Schedule Disclosure Schedule
 Customers/Clients and Suppliers. Disclosure Schedule
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Real Property. Disclosure Schedule Disclosure Schedule
      Leases. Disclosure Schedule
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Disclosure Schedule
 Inventory.
 Employee Benefit Plans.
 Disclosure Schedule Disclosure Schedule
    Disclosure Schedule
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Disclosure Schedule
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Employment Contracts. Disclosure Schedule
   Labour Matters.
  Disclosure Schedule Disclosure Schedule Disclosure Schedule
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Accounts Receivable.
 Taxes. Disclosure Schedule
 Tax
Returns Employment Insurance Act
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Excise Tax Act
 Tangible Personal Property. Disclosure Schedule
 Absence of Certain Business Practices.
 Books and Records.
 Powers of Attorney; Authorized Signatories. Disclosure Schedule
 Agreements with Sellers. Disclosure
Schedule
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Bankruptcy and Insolvency Matters.
 Resident of Canada.
 Unanimous Shareholder Agreements
 Remuneration of Certain Persons.
 Delivery of Documents. Disclosure Schedule
 Disclosure.
 Representations and Warranties of Purchaser.
 Organization of Purchaser.
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Authority.
 Validity and Binding Effect.
 Noncontravention.
 Consents and Approvals.
 Litigation.
 Funding.
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Investment Intent.
 Disclosure.
 ARTICLE V
COVENANTS
 Conduct of Business by the Midwest Group Pending Closing.
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Disclosure Schedule
   Access to Assets, Personnel and Information.
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No Solicitation.
 Additional Arrangements.
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Payment of Expenses.
 Public Announcements.
 Tax Returns.
 Pre-Closing Transactions.
 Further Assurances.
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Taxes.
 Confidentiality.
   Noncompetition.
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Employees.
 Brokers Fees.
 Mutual Cooperation.
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Preservation of Files and Records.
 Compliance with Law and Rules. FCPA
 Privacy Matters.
 Disclosed Personal Information. Disclosed Personal Information
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No Unrelated Use.
 Necessary Disclosure.
 Applicable Measures.
 Duty to Keep Confidential. bona fide
 Duty to notify.
 Duty to Return or Destroy.
 Environmental Inspection.
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Golder Phase I Golder Phase II
 Environmental Remediation; Further Inspection.
     Inter-company Indebtedness.
 Competition Act.
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Prohibited Acquisitions.
   ARTICLE VI
CONDITIONS
 Conditions to Each Partys Obligation to Proceed with Closing.
 Approvals.
 No Injunctions or Restraints.
 6.2 Conditions to Obligations of Purchaser.
 Representations and Warranties.
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Performance of Covenants and Agreements by Seller.
 Conditions to Obligations of Seller.
 Representations and Warranties.
 Performance of Covenants and Agreements by Purchaser.
 ARTICLE VII
TERMINATION
 Termination Rights.
  Bureau
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Effect of Termination.
 ARTICLE VIII
INDEMNIFICATION AND THIRD PARTY CLAIMS
 Indemnification.
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Indemnifying Party related persons Indemnified Person Claim
 Defense of Third Party Claims.
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Disclosure Schedule
 Limit on Indemnity Obligations.
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Threshold
 Bonding.
 Other Indemnification Rights.
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Survival.
 ARTICLE IX
MISCELLANEOUS
 Governing Law.
 Counterparts.
 Assignment; Binding Effect.
 Entire Agreement.
 Notices.
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-46-




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Amendment.
 Severability.
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Waivers.
 Enforcement of Agreement.
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Purchaser
    
    
    
    SellersWillbros Acquisition Canada Limited
    
    
    
    AMEC Inc.By:
    
    /s/ Gay Stanley Mayeux
    
    
    
    By:
    
    /s/ Tarun BafnaGay Stanley Mayeux
    
    
    
    
    
    Tarun BafnaAttorney-in-Fact
    
    
    
    
    
    Authorized SignerAMEC Americas LimitedBy:
    
    /s/ Tarun BafnaTarun BafnaAuthorized Signer
 Guarantee
  By:
    
    /s/ Gay Stanley Mayeux
    
    
    
    By:
    
    /s/ William L. PardueGay Stanley Mayeux
    
    
    
    
    
    William L. PardueAttorney-in-Fact
    
    
    
    
    
    Deputy Corporate Secretary
 Disclosure Schedule *
 
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