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    <link:label id="lab_mtrx_LineOfCreditBasisSpreadOnAlternateBaseRateMaximum_71D0333E1298EBBE8148F3D43385543A_documentation_en-US" xlink:label="lab_mtrx_LineOfCreditBasisSpreadOnAlternateBaseRateMaximum_71D0333E1298EBBE8148F3D43385543A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of credit basis spread on alternate base rate maximum.</link:label>
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    <link:label id="lab_mtrx_SublimitonAustralianDollarCanadianDollarEuroandPoundsSterling_BB659D77BA4DC6ECF5F1F3D4338560CA_documentation_en-US" xlink:label="lab_mtrx_SublimitonAustralianDollarCanadianDollarEuroandPoundsSterling_BB659D77BA4DC6ECF5F1F3D4338560CA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Sublimit on Australian Dollar, Canadian Dollar, Euro and Pounds Sterling</link:label>
    <link:loc xlink:href="mtrx-20170331.xsd#mtrx_SublimitonAustralianDollarCanadianDollarEuroandPoundsSterling" xlink:label="loc_mtrx_SublimitonAustralianDollarCanadianDollarEuroandPoundsSterling_BB659D77BA4DC6ECF5F1F3D4338560CA" xlink:type="locator" />
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    <link:label id="lab_mtrx_Sublimitonlettersofcreditunderthecreditfacility_B14CE01AFA7D86BDEB02F3D43385E2F4_terseLabel_en-US" xlink:label="lab_mtrx_Sublimitonlettersofcreditunderthecreditfacility_B14CE01AFA7D86BDEB02F3D43385E2F4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sub-limit on letters of credit under the credit facility</link:label>
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    <link:loc xlink:href="mtrx-20170331.xsd#mtrx_Sublimitonlettersofcreditunderthecreditfacility" xlink:label="loc_mtrx_Sublimitonlettersofcreditunderthecreditfacility_B14CE01AFA7D86BDEB02F3D43385E2F4" xlink:type="locator" />
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    <link:label id="lab_mtrx_LineOfCreditBasisSpreadOnAdjustedLIBOEURIBOandCDORMinimum_90222F2E474549C85F4FF3D4338528D4_documentation_en-US" xlink:label="lab_mtrx_LineOfCreditBasisSpreadOnAdjustedLIBOEURIBOandCDORMinimum_90222F2E474549C85F4FF3D4338528D4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Line of credit basis spread on Adjusted LIBO, EURIBO and CDOR loans rate minimum.</link:label>
    <link:loc xlink:href="mtrx-20170331.xsd#mtrx_LineOfCreditBasisSpreadOnAdjustedLIBOEURIBOandCDORMinimum" xlink:label="loc_mtrx_LineOfCreditBasisSpreadOnAdjustedLIBOEURIBOandCDORMinimum_90222F2E474549C85F4FF3D4338528D4" xlink:type="locator" />
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    <link:loc xlink:href="mtrx-20170331.xsd#mtrx_LineOfCreditBasisSpreadOnCanadianPrimeRateMinimum" xlink:label="loc_mtrx_LineOfCreditBasisSpreadOnCanadianPrimeRateMinimum_063D20F949006AB81313F3D433858B3F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_FurnitureAndFixturesGross_3AE55341FAA48849347DEE45107C4260_label_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesGross_3AE55341FAA48849347DEE45107C4260" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Furniture and Fixtures, Gross</link:label>
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    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_A06D69AE61B9E6787E2DF344BAA1FCF6_terseLabel_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts_A06D69AE61B9E6787E2DF344BAA1FCF6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Provision for uncollectible accounts</link:label>
    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_A06D69AE61B9E6787E2DF344BAA1FCF6_label_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts_A06D69AE61B9E6787E2DF344BAA1FCF6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Provision for Doubtful Accounts</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensation_60D6183FE6C0E000B667F344BAA179D0_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_60D6183FE6C0E000B667F344BAA179D0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensation_60D6183FE6C0E000B667F344BAA179D0_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_60D6183FE6C0E000B667F344BAA179D0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation</link:label>
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    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_F9FB639C402FCC5F85BFF344BAA15812_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_F9FB639C402FCC5F85BFF344BAA15812" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_F9FB639C402FCC5F85BFF344BAA15812_label_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_F9FB639C402FCC5F85BFF344BAA15812" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Noncash Income (Expense)</link:label>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_F65A44E5F8FA6F68A0EAF344BAA17480_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_F65A44E5F8FA6F68A0EAF344BAA17480" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Receivable</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_F65A44E5F8FA6F68A0EAF344BAA17480" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract_81F7733150B5E297DD7DF344BAA156C5_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract_81F7733150B5E297DD7DF344BAA156C5" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Costs and estimated earnings in excess of billings on uncompleted contracts</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract" xlink:label="loc_us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract_81F7733150B5E297DD7DF344BAA156C5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract_81F7733150B5E297DD7DF344BAA156C5" xlink:to="lab_us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract_81F7733150B5E297DD7DF344BAA156C5" xlink:type="arc" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInInventories_D35DEA3B24BA84F5FC4CF344BAA15F2D_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInInventories_D35DEA3B24BA84F5FC4CF344BAA15F2D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Inventories</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_D35DEA3B24BA84F5FC4CF344BAA15F2D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_C004C32B885B4297AD73F344BAA15799_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_C004C32B885B4297AD73F344BAA15799" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other assets and liabilities</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_C004C32B885B4297AD73F344BAA15799" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_3138AF36FC607712035BF344BAA17EA4" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInBillingInExcessOfCostOfEarnings_0FE878A3EA1F578A027FF344BAA1DB8B_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInBillingInExcessOfCostOfEarnings_0FE878A3EA1F578A027FF344BAA1DB8B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Billings on uncompleted contracts in excess of costs and estimated earnings</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_CEF762C8384A4E89B28AF344BAA10866_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_CEF762C8384A4E89B28AF344BAA10866" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided (used) by operating activities</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLongTermLinesOfCredit_416D2F2AE0A2C3B15332F344BAA11DED" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_E5EDFACC86086856B4F3F344BAA1F390" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_A9F3D0A88C347BA0A3D4F344BAA106C0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_A9F3D0A88C347BA0A3D4F344BAA106C0" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Open market purchase of treasury shares</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_A9F3D0A88C347BA0A3D4F344BAA106C0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromStockPlans_6ACBAA4F03C12AAB8A1DF344BAA15310_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromStockPlans_6ACBAA4F03C12AAB8A1DF344BAA15310" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from issuance of common stock under employee stock purchase plan</link:label>
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    <link:label id="lab_us-gaap_GoodwillGross_149831A0C3FBCAFC9D29EE450FFBB614_label_en-US" xlink:label="lab_us-gaap_GoodwillGross_149831A0C3FBCAFC9D29EE450FFBB614" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_149831A0C3FBCAFC9D29EE450FFBB614" xlink:type="locator" />
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    <link:label id="lab_us-gaap_GoodwillRollForward_B56A4B8D779D45AB12BFEE450FFB415D_label_en-US" xlink:label="lab_us-gaap_GoodwillRollForward_B56A4B8D779D45AB12BFEE450FFB415D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill [Roll Forward]</link:label>
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    <link:label id="lab_us-gaap_Goodwill_9F4236E66458EA2D7F14EE450FFB2167_periodStartLabel_en-US" xlink:label="lab_us-gaap_Goodwill_9F4236E66458EA2D7F14EE450FFB2167" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xml:lang="en-US">Net balance at June 30, 2015</link:label>
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    <link:label id="lab_mtrx_PowerGenerationProjectUnapprovedChangeOrdersandClaimsTable_A7D5DAF26E9B61C07A4F3EF67589B952_terseLabel_en-US" xlink:label="lab_mtrx_PowerGenerationProjectUnapprovedChangeOrdersandClaimsTable_EBD175659FDC50C5AFF4BDB0258CFB03" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Power Generation Project Unapproved Change Orders and Claims [Table]</link:label>
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