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        <link:definition>0039 - Disclosure - SHARE CAPITAL (Narrative) (Details)</link:definition>
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        <link:definition>0041 - Disclosure - SUPPLEMENTAL DISCLOSURE WITH RESPECT TO CASH FLOWS (Narrative) (Details)</link:definition>
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        <link:definition>0044 - Disclosure - ACCOUNTS RECEIVABLE - Schedule of detailed information about accounts receivable (Details)</link:definition>
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        <link:definition>0045 - Disclosure - ROYALTY, STREAM, AND OTHER INTERESTS - Schedule of detailed information about royalty interests and deferred acquisition costs (Details)</link:definition>
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        <link:definition>0046 - Disclosure - ROYALTY, STREAM, AND OTHER INTERESTS - Schedule of detailed information about purchase price allocation for acquisition (Details)</link:definition>
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  <element name="DisclosureOfContractualCapitalCommitmentsTableTextBlock" id="mtaff_DisclosureOfContractualCapitalCommitmentsTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutNetChangeInNonCashWorkingCapitalItemsExplanantoryTextBlock" id="mtaff_DisclosureOfDetailedInformationAboutNetChangeInNonCashWorkingCapitalItemsExplanantoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutPurchasePriceAllocationForAcquisitionExplanatoryTextBlock" id="mtaff_DisclosureOfDetailedInformationAboutPurchasePriceAllocationForAcquisitionExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutRoyaltyInterestsAndDeferredAcquisitionCostsExplanatoryTextBlock" id="mtaff_DisclosureOfDetailedInformationAboutRoyaltyInterestsAndDeferredAcquisitionCostsExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutTradeAndOtherPayablesTableTextBlock" id="mtaff_DisclosureOfDetailedInformationAboutTradeAndOtherPayablesTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutTradeAndOtherReceivablesExplanatoryTextBlock" id="mtaff_DisclosureOfDetailedInformationAboutTradeAndOtherReceivablesExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfDetailedInformationAboutTradeAndOthersPayableAbstract" id="mtaff_DisclosureOfDetailedInformationAboutTradeAndOthersPayableAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfIncomeTaxExpenseReconciliationExplanatory" id="mtaff_DisclosureOfIncomeTaxExpenseReconciliationExplanatory" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfLoansPayableLineItems" id="mtaff_DisclosureOfLoansPayableLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfLoansPayableTable" id="mtaff_DisclosureOfLoansPayableTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="DisclosureOfNatureOfOperationsExplanatoryTextBlock" id="mtaff_DisclosureOfNatureOfOperationsExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfNumberAndWeightedAverageExercisePricesOfOtherEquityInstrumentsRestrictedShareUnitsExplanatory" id="mtaff_DisclosureOfNumberAndWeightedAverageExercisePricesOfOtherEquityInstrumentsRestrictedShareUnitsExplanatory" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfRangeOfExercisePricesOfOutstandingWarrantsExplanatoryTableTextBlock" id="mtaff_DisclosureOfRangeOfExercisePricesOfOutstandingWarrantsExplanatoryTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsExplanatoryTextBlock" id="mtaff_DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsLineItems" id="mtaff_DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsTable" id="mtaff_DisclosureOfRoyaltyInterestsAndDeferredAcquisitionCostsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="DisclosureOfSignificantAccountingPoliciesAbstract" id="mtaff_DisclosureOfSignificantAccountingPoliciesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DisclosureOfWarrantsActivityExplanatoryTextBlock" id="mtaff_DisclosureOfWarrantsActivityExplanatoryTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DocumentAndEntityInformationAbstract" id="mtaff_DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="DufferinEastAcquisitionMember" id="mtaff_DufferinEastAcquisitionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="EffectiveInterestRateOnLiability" id="mtaff_EffectiveInterestRateOnLiability" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="EitherHoylePondMineOrWestTimminsMineMember" id="mtaff_EitherHoylePondMineOrWestTimminsMineMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ElRealitoNsrMember" id="mtaff_ElRealitoNsrMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="EndeavorStreamInterestAsOfAcquisitionDate" id="mtaff_EndeavorStreamInterestAsOfAcquisitionDate" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="EquityIssuancePricePerShare" id="mtaff_EquityIssuancePricePerShare" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="EstimatedDeliveryOfPayableSilver" id="mtaff_EstimatedDeliveryOfPayableSilver" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="EventsAfterReportingPeriodMember" id="mtaff_EventsAfterReportingPeriodMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExceedingSilverPricePerOunce" id="mtaff_ExceedingSilverPricePerOunce" type="srt-types:perUnitItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExemptionOnGoldProduced" id="mtaff_ExemptionOnGoldProduced" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExercisePriceOfWarrantsIssued" id="mtaff_ExercisePriceOfWarrantsIssued" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExercisePriceOfWarrantsIssuedWithinUnits" id="mtaff_ExercisePriceOfWarrantsIssuedWithinUnits" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpectedDividendAsPercentageWarrantsGranted" id="mtaff_ExpectedDividendAsPercentageWarrantsGranted" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpectedLifeOfLiability" id="mtaff_ExpectedLifeOfLiability" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpectedLifeOfWarrantsGranted" id="mtaff_ExpectedLifeOfWarrantsGranted" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpectedVolatilityWarrantsGranted" id="mtaff_ExpectedVolatilityWarrantsGranted" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateAugust112021Member" id="mtaff_ExpiryDateAugust112021Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateAugust302021Member" id="mtaff_ExpiryDateAugust302021Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateAxis" id="mtaff_ExpiryDateAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" nillable="true"/>
  <element name="ExpiryDateDecember052020Member" id="mtaff_ExpiryDateDecember052020Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateDecember212020Member" id="mtaff_ExpiryDateDecember212020Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateDecember212020OneMember" id="mtaff_ExpiryDateDecember212020OneMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateDomain" id="mtaff_ExpiryDateDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJan042024Member" id="mtaff_ExpiryDateJan042024Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJan152025Member" id="mtaff_ExpiryDateJan152025Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJanuary042021Member" id="mtaff_ExpiryDateJanuary042021Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJanuary042021OneMember" id="mtaff_ExpiryDateJanuary042021OneMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJul152021Member" id="mtaff_ExpiryDateJul152021Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateJul312022Member" id="mtaff_ExpiryDateJul312022Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateMar012023Member" id="mtaff_ExpiryDateMar012023Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateMar062022Member" id="mtaff_ExpiryDateMar062022Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
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  <element name="ExpiryDateNov302021Member" id="mtaff_ExpiryDateNov302021Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateNovember082020Member" id="mtaff_ExpiryDateNovember082020Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ExpiryDateOctober062019Member" id="mtaff_ExpiryDateOctober062019Member" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
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  <element name="FairValueAtMeasurementDateShareOptionsGranted" id="mtaff_FairValueAtMeasurementDateShareOptionsGranted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="FairValueOfRestrictedShareUnitsGranted" id="mtaff_FairValueOfRestrictedShareUnitsGranted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="FairValueOfWarrantsIssued" id="mtaff_FairValueOfWarrantsIssued" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="FifteenMileStreamAcquisitionsMember" id="mtaff_FifteenMileStreamAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="FiloAcquisitionsMember" id="mtaff_FiloAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="FinancingBonusReceived" id="mtaff_FinancingBonusReceived" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="FinderFeesPaid" id="mtaff_FinderFeesPaid" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="FindersShareIssueRelatedCosts" id="mtaff_FindersShareIssueRelatedCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="FindersWarrantsShareIssueRelatedCosts" id="mtaff_FindersWarrantsShareIssueRelatedCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="GarrisonProjectNsrMember" id="mtaff_GarrisonProjectNsrMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="HalfOfNetSmelterReturnAcquiredPercentage" id="mtaff_HalfOfNetSmelterReturnAcquiredPercentage" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="HighStreamCorpMember" id="mtaff_HighStreamCorpMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="HistoricalCostsRoyaltyAndStreamInterests" id="mtaff_HistoricalCostsRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="HolyePondExtensionPropertyMember" id="mtaff_HolyePondExtensionPropertyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IdahoResourcesCorpAcquisitionMember" id="mtaff_IdahoResourcesCorpAcquisitionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IepiAcquisitionsMember" id="mtaff_IepiAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncomeTaxesAbstract" id="mtaff_IncomeTaxesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseInDeferredAcquisitionCosts" id="mtaff_IncreaseDecreaseInDeferredAcquisitionCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseLoansPayableThroughIssuedOfWarrants" id="mtaff_IncreaseDecreaseLoansPayableThroughIssuedOfWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreasePrepaidExpensesAndOther" id="mtaff_IncreaseDecreasePrepaidExpensesAndOther" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="IncreaseDecreaseSharesThroughConversionOnLoanPayable" id="mtaff_IncreaseDecreaseSharesThroughConversionOnLoanPayable" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterest" id="mtaff_IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterest" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterests" id="mtaff_IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterestsInShares" id="mtaff_IncreaseDecreaseThroughAcquisitionOfRoyaltyAndStreamInterestsInShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughAcquisitionOfRoyaltyInterests" id="mtaff_IncreaseDecreaseThroughAcquisitionOfRoyaltyInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughAllocationOfConversionFeature" id="mtaff_IncreaseDecreaseThroughAllocationOfConversionFeature" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughExerciseOfOptionsShares" id="mtaff_IncreaseDecreaseThroughExerciseOfOptionsShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughExerciseOfWarrantsEquityInShares" id="mtaff_IncreaseDecreaseThroughExerciseOfWarrantsEquityInShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughPerformanceBasedPaymentTransactions" id="mtaff_IncreaseDecreaseThroughPerformanceBasedPaymentTransactions" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughPerformanceBasedPaymentTransactionsInShare" id="mtaff_IncreaseDecreaseThroughPerformanceBasedPaymentTransactionsInShare" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughPrivatePlacementsAndShareIssuances" id="mtaff_IncreaseDecreaseThroughPrivatePlacementsAndShareIssuances" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughPrivatePlacementsAndShareIssuancesShares" id="mtaff_IncreaseDecreaseThroughPrivatePlacementsAndShareIssuancesShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="IncreaseDecreaseThroughShareBasedPaymentTransactionsOffsettingCreditOfReserves" id="mtaff_IncreaseDecreaseThroughShareBasedPaymentTransactionsOffsettingCreditOfReserves" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughShareBasedPaymentTransactionsOffsettingCreditOfShareCapital" id="mtaff_IncreaseDecreaseThroughShareBasedPaymentTransactionsOffsettingCreditOfShareCapital" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="IncreaseDecreaseThroughShareBasedPaymentTransactionsVestingTermsOfRSUGranted" id="mtaff_IncreaseDecreaseThroughShareBasedPaymentTransactionsVestingTermsOfRSUGranted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="InducementsToLoanPayable" id="mtaff_InducementsToLoanPayable" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="InflectionCapitalIncMember" id="mtaff_InflectionCapitalIncMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="InitialAdvanceDrewDownAllocatedToConversionFeature" id="mtaff_InitialAdvanceDrewDownAllocatedToConversionFeature" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="InitialAdvanceDrewDownAllocatedToLiabilityPortion" id="mtaff_InitialAdvanceDrewDownAllocatedToLiabilityPortion" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="InitialAdvanceOfConvertibleLoanFacility" id="mtaff_InitialAdvanceOfConvertibleLoanFacility" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="InterestRateOnStandbyFundsAvailable" id="mtaff_InterestRateOnStandbyFundsAvailable" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="JoaquinProjectMember" id="mtaff_JoaquinProjectMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="JoaquinRoyaltyMember" id="mtaff_JoaquinRoyaltyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="KirklandLakeGoldLtdMember" id="mtaff_KirklandLakeGoldLtdMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LaFortunaNsrOptionMember" id="mtaff_LaFortunaNsrOptionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LegalEntitiesAxis" id="mtaff_LegalEntitiesAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" nillable="true"/>
  <element name="LegalEntitiesDomain" id="mtaff_LegalEntitiesDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LoanAgreementSettled" id="mtaff_LoanAgreementSettled" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="LoanAgreementsForAggregateAmount" id="mtaff_LoanAgreementsForAggregateAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="LoanAgreementsWithLendersMember" id="mtaff_LoanAgreementsWithLendersMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LoanPayableAbstract" id="mtaff_LoanPayableAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LoanPayableAxis" id="mtaff_LoanPayableAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" nillable="true"/>
  <element name="LoanPayableDomain" id="mtaff_LoanPayableDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LoanPayableLineItems" id="mtaff_LoanPayableLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LoanPayableTable" id="mtaff_LoanPayableTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="LoansSettlement" id="mtaff_LoansSettlement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="LosPlatosProjectNsrMember" id="mtaff_LosPlatosProjectNsrMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="LossOnSettlementOfLoanAgreement" id="mtaff_LossOnSettlementOfLoanAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="MarketableSecurities" id="mtaff_MarketableSecurities" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="MarketableSecuritiesRecognisedAsOfAcquisitionDate" id="mtaff_MarketableSecuritiesRecognisedAsOfAcquisitionDate" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="MatamecAcquisitionsMember" id="mtaff_MatamecAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="MaximumCappingOfNetSmelterReturnNsr" id="mtaff_MaximumCappingOfNetSmelterReturnNsr" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="MaximumCappingOfUnsecuredNetSmelterReturnNsr" id="mtaff_MaximumCappingOfUnsecuredNetSmelterReturnNsr" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="MineralExpendituresAndCapitalAssetsMember" id="mtaff_MineralExpendituresAndCapitalAssetsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="MineraTritonArgentinaMember" id="mtaff_MineraTritonArgentinaMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="MinimumTranchesOfConvertibleLoanFacility" id="mtaff_MinimumTranchesOfConvertibleLoanFacility" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="MiradoMineProjectMember" id="mtaff_MiradoMineProjectMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="MontclergPropertyMember" id="mtaff_MontclergPropertyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NatureOfOperationsAbstract" id="mtaff_NatureOfOperationsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NetSmelterReturn" id="mtaff_NetSmelterReturn" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NetSmelterReturnAcquiredPercentage" id="mtaff_NetSmelterReturnAcquiredPercentage" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NetSmelterReturnAcquisitionRange" id="mtaff_NetSmelterReturnAcquisitionRange" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NonCapitalLossesAndOtherMember" id="mtaff_NonCapitalLossesAndOtherMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NuevaUnionAcquisitionMember" id="mtaff_NuevaUnionAcquisitionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfBulkTonnageModel" id="mtaff_NumberOfBulkTonnageModel" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesAcquisition" id="mtaff_NumberOfCommonSharesAcquisition" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesIssuedForAcquisitionsOfRoyaltyInterests" id="mtaff_NumberOfCommonSharesIssuedForAcquisitionsOfRoyaltyInterests" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesIssuedForNetAssetsAcquired" id="mtaff_NumberOfCommonSharesIssuedForNetAssetsAcquired" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesIssuedForVestingOfRestrictedStockUnits" id="mtaff_NumberOfCommonSharesIssuedForVestingOfRestrictedStockUnits" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesReceivedForExchangeRatio" id="mtaff_NumberOfCommonSharesReceivedForExchangeRatio" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfCommonSharesWarrantsIssuedAsDeferredAcquisitionCosts" id="mtaff_NumberOfCommonSharesWarrantsIssuedAsDeferredAcquisitionCosts" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfFindersWarrantsIssued" id="mtaff_NumberOfFindersWarrantsIssued" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfInferredResourceInOunces" id="mtaff_NumberOfInferredResourceInOunces" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfNsrInterestsAcquired" id="mtaff_NumberOfNsrInterestsAcquired" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfOutstandingWarrants" id="mtaff_NumberOfOutstandingWarrants" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfPostConsolidationCommonShares" id="mtaff_NumberOfPostConsolidationCommonShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfPreConsolidationCommonShares" id="mtaff_NumberOfPreConsolidationCommonShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfRoyaltyInterest" id="mtaff_NumberOfRoyaltyInterest" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharePurchaseWarrantsExercised" id="mtaff_NumberOfSharePurchaseWarrantsExercised" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharePurchaseWarrantsIssuedForAcquisitionsOfRoyaltyInterests" id="mtaff_NumberOfSharePurchaseWarrantsIssuedForAcquisitionsOfRoyaltyInterests" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharePurchaseWarrantsIssuedOnSettlementOfLoansPayable" id="mtaff_NumberOfSharePurchaseWarrantsIssuedOnSettlementOfLoansPayable" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesInPublicOfferingPreviouslyHeld" id="mtaff_NumberOfSharesInPublicOfferingPreviouslyHeld" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriod" id="mtaff_NumberOfSharesIssuedDuringPeriod" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriodForAcquisitionOfRoyaltyAndStreamInterests" id="mtaff_NumberOfSharesIssuedDuringPeriodForAcquisitionOfRoyaltyAndStreamInterests" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriodForConversionOfCoeurConvertibleDebenture" id="mtaff_NumberOfSharesIssuedDuringPeriodForConversionOfCoeurConvertibleDebenture" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriodForExerciseOfSharePurchaseWarrants" id="mtaff_NumberOfSharesIssuedDuringPeriodForExerciseOfSharePurchaseWarrants" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriodForVestingOfRSUAndExerciseOfStockOptions" id="mtaff_NumberOfSharesIssuedDuringPeriodForVestingOfRSUAndExerciseOfStockOptions" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfSharesIssuedDuringPeriodValue" id="mtaff_NumberOfSharesIssuedDuringPeriodValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="NumberOfSilverStreamInterests" id="mtaff_NumberOfSilverStreamInterests" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfUnderwritersWarrantsIssued" id="mtaff_NumberOfUnderwritersWarrantsIssued" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfWarrantsExercised" id="mtaff_NumberOfWarrantsExercised" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfWarrantsExpired" id="mtaff_NumberOfWarrantsExpired" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="NumberOfWarrantsIssued" id="mtaff_NumberOfWarrantsIssued" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OperatingCostContributionPricePerOunce" id="mtaff_OperatingCostContributionPricePerOunce" type="srt-types:perUnitItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OrefindersAcquisitionsMember" id="mtaff_OrefindersAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OrionNsrRoyaltyMember" id="mtaff_OrionNsrRoyaltyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OtherAcquisitionCostsOfRoyaltyAndStreamInterests" id="mtaff_OtherAcquisitionCostsOfRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="OtherAdditionsRoyaltyAndStreamInterests" id="mtaff_OtherAdditionsRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="OtherCommitmentMember" id="mtaff_OtherCommitmentMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OtherLoanPayableMember" id="mtaff_OtherLoanPayableMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="OtherRoyaltyInterestsMember" id="mtaff_OtherRoyaltyInterestsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageIncrementsOfExceededSilverPricePerOunce" id="mtaff_PercentageIncrementsOfExceededSilverPricePerOunce" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfAdditionalInterestAcquired" id="mtaff_PercentageOfAdditionalInterestAcquired" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfCashAndCommonSharesPay" id="mtaff_PercentageOfCashAndCommonSharesPay" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfEquityOwnershipOtherCompanyNeedsToMaintainInOrderForAutomaticConversionToApply" id="mtaff_PercentageOfEquityOwnershipOtherCompanyNeedsToMaintainInOrderForAutomaticConversionToApply" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfMaximumNumberOfRestrictedShareUnitsSharesReservedForIssuance" id="mtaff_PercentageOfMaximumNumberOfRestrictedShareUnitsSharesReservedForIssuance" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfMaximumNumberOfSharesReservedForIssuanceUnderStockOptionPlan" id="mtaff_PercentageOfMaximumNumberOfSharesReservedForIssuanceUnderStockOptionPlan" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageOfNetSmelterReturnRoyaltyAcquired" id="mtaff_PercentageOfNetSmelterReturnRoyaltyAcquired" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PercentageRightToBuySilverProduction" id="mtaff_PercentageRightToBuySilverProduction" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PresidentAndCeoMember" id="mtaff_PresidentAndCeoMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PricePerSharePurchaseWarrantOutstandingExercisableAcquisition" id="mtaff_PricePerSharePurchaseWarrantOutstandingExercisableAcquisition" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PrincipalPaymentDuePeriod" id="mtaff_PrincipalPaymentDuePeriod" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ProceedsFromExerciseOfSharePurchaseWarrants" id="mtaff_ProceedsFromExerciseOfSharePurchaseWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="ProceedsFromSaleOfProject" id="mtaff_ProceedsFromSaleOfProject" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="PuchuldizaProjectMember" id="mtaff_PuchuldizaProjectMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PurchaseAndSaleAgreementMember" id="mtaff_PurchaseAndSaleAgreementMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="PurchasePriceForAdditionalNetSmelterRoyalty" id="mtaff_PurchasePriceForAdditionalNetSmelterRoyalty" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="PurchasePriceOfAcquisitionPaidInCash" id="mtaff_PurchasePriceOfAcquisitionPaidInCash" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="PurchasePriceOfAgreement" id="mtaff_PurchasePriceOfAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="PurchasePriceOfAgreementPayableInShares" id="mtaff_PurchasePriceOfAgreementPayableInShares" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ReallocationFromReservesForSharePurchaseWarrantsExercised" id="mtaff_ReallocationFromReservesForSharePurchaseWarrantsExercised" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ReallocationFromReservesForStockOptionsExercised" id="mtaff_ReallocationFromReservesForStockOptionsExercised" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ReallocationOfDeferredAcquisitionCostsToRoyaltyAndStreamInterestsOnClosingOfAcquisition" id="mtaff_ReallocationOfDeferredAcquisitionCostsToRoyaltyAndStreamInterestsOnClosingOfAcquisition" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ReclassificationOfRoyaltyAndStreamInterests" id="mtaff_ReclassificationOfRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="RecoveriesFromRoyaltyAndStreamInterests" id="mtaff_RecoveriesFromRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RecoveriesOfRoyaltyAndStreamInterests" id="mtaff_RecoveriesOfRoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RedHillNsrMember" id="mtaff_RedHillNsrMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RepaymentOfThirdPartyLoans" id="mtaff_RepaymentOfThirdPartyLoans" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="RepaymentsOfFinanceChargesPaid" id="mtaff_RepaymentsOfFinanceChargesPaid" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ReserveForSharePurchaseWarrants" id="mtaff_ReserveForSharePurchaseWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="RestrictedStockUnitIssuedToDirectorsAndOfficers" id="mtaff_RestrictedStockUnitIssuedToDirectorsAndOfficers" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ResultOfIndependentMineralResourceEstimationReport" id="mtaff_ResultOfIndependentMineralResourceEstimationReport" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RevenueFromRoyaltyInterests" id="mtaff_RevenueFromRoyaltyInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="RevenueFromStreamInterest" id="mtaff_RevenueFromStreamInterest" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="RevenueLineItems" id="mtaff_RevenueLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RevenueTable" id="mtaff_RevenueTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="RevisedConversionPrice" id="mtaff_RevisedConversionPrice" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RightOfFirstRefusal" id="mtaff_RightOfFirstRefusal" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RightOfUseAssetOfLeaseLiability" id="mtaff_RightOfUseAssetOfLeaseLiability" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RightToBuyBackStreamAmount" id="mtaff_RightToBuyBackStreamAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RightToBuySilverProduction" id="mtaff_RightToBuySilverProduction" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RightToDeliverSilverProductionOuncesDelivered" id="mtaff_RightToDeliverSilverProductionOuncesDelivered" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RightToDeliverSilverProductionOuncesRemainingToBeDelivered" id="mtaff_RightToDeliverSilverProductionOuncesRemainingToBeDelivered" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RiskFreeInterestRateWarrantsGranted" id="mtaff_RiskFreeInterestRateWarrantsGranted" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="RoyaltyAndStreamInterests" id="mtaff_RoyaltyAndStreamInterests" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RoyaltyInterestsAndDeferredAcquisitionCosts" id="mtaff_RoyaltyInterestsAndDeferredAcquisitionCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="RoyaltyInterestsAndDeferredAcquisitionCostsAbstract" id="mtaff_RoyaltyInterestsAndDeferredAcquisitionCostsAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SaleOfAcquisitionToOriginalOwner" id="mtaff_SaleOfAcquisitionToOriginalOwner" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="SaleOfStocksAxis" id="mtaff_SaleOfStocksAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" nillable="true"/>
  <element name="SaleOfStocksDomain" id="mtaff_SaleOfStocksDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SantaGertrudisAcquisitionsMember" id="mtaff_SantaGertrudisAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SantaGertrudisAcquisitonsMember" id="mtaff_SantaGertrudisAcquisitonsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ScheduleOfDetailedInformationAboutTradeAndOthersPayableAbstract" id="mtaff_ScheduleOfDetailedInformationAboutTradeAndOthersPayableAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ScheduleOfWarrantLineItems" id="mtaff_ScheduleOfWarrantLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ScheduleOfWarrantTable" id="mtaff_ScheduleOfWarrantTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="SecondaryOfferingMember" id="mtaff_SecondaryOfferingMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SecuredLoanAgreementsAggregateAmount" id="mtaff_SecuredLoanAgreementsAggregateAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="SensitivityAnalysisVariancePrice" id="mtaff_SensitivityAnalysisVariancePrice" type="num:percentItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ShareIssueCostsMember" id="mtaff_ShareIssueCostsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ShareOptionForfeitureRate" id="mtaff_ShareOptionForfeitureRate" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SharePricePerShare" id="mtaff_SharePricePerShare" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SharePurchaseWarrantExercisePriceTerm" id="mtaff_SharePurchaseWarrantExercisePriceTerm" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SharePurchaseWarrantOutstandingExercisableAcquisition" id="mtaff_SharePurchaseWarrantOutstandingExercisableAcquisition" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SharePurchaseWarrantsIssued" id="mtaff_SharePurchaseWarrantsIssued" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="StockOptionsPlanExpense" id="mtaff_StockOptionsPlanExpense" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="SupplementalDisclosureOfCashFlowAbstract" id="mtaff_SupplementalDisclosureOfCashFlowAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SupplementalDisclosureOfCashFlowLineItems" id="mtaff_SupplementalDisclosureOfCashFlowLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="SupplementalDisclosureOfCashFlowTable" id="mtaff_SupplementalDisclosureOfCashFlowTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" nillable="true"/>
  <element name="TaxEffectOfChangesInUnrecognizedDeferredTaxAssets" id="mtaff_TaxEffectOfChangesInUnrecognizedDeferredTaxAssets" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="TermOfConvertibleDebenturePayable" id="mtaff_TermOfConvertibleDebenturePayable" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TermOfExerciseOfOption" id="mtaff_TermOfExerciseOfOption" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TermOfWarrants" id="mtaff_TermOfWarrants" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TowerMountainAcquisitionMember" id="mtaff_TowerMountainAcquisitionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TowerMountainProjectMember" id="mtaff_TowerMountainProjectMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TradeAndOtherPayablesMember" id="mtaff_TradeAndOtherPayablesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="TypeOfArrangementsAxis" id="mtaff_TypeOfArrangementsAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" nillable="true"/>
  <element name="TypeOfArrangementsDomain" id="mtaff_TypeOfArrangementsDomain" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="UnitsIssuedInPeriod" id="mtaff_UnitsIssuedInPeriod" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="UnitsIssuedInPeriodPricePerUnit" id="mtaff_UnitsIssuedInPeriodPricePerUnit" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="UpfrontPaymentMadeUponExerciseOfOption" id="mtaff_UpfrontPaymentMadeUponExerciseOfOption" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ValgoldAcquisitionsMember" id="mtaff_ValgoldAcquisitionsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ValueOfCommonSharesAcquisition" id="mtaff_ValueOfCommonSharesAcquisition" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ValueOfRestrictedStockUnitIssuedToDirectorsAndOfficers" id="mtaff_ValueOfRestrictedStockUnitIssuedToDirectorsAndOfficers" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="ValueOfSharePurchaseWarrantsIssued" id="mtaff_ValueOfSharePurchaseWarrantsIssued" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="ValueOfSharesIssuedForVestingOfRestrictedStockUnits" id="mtaff_ValueOfSharesIssuedForVestingOfRestrictedStockUnits" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ValueOfUnderwritersWarrantsIssued" id="mtaff_ValueOfUnderwritersWarrantsIssued" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit"/>
  <element name="ValueOfUnderwriterWarrantsIssued" id="mtaff_ValueOfUnderwriterWarrantsIssued" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="ValueOfUnitsIssuedInPeriod" id="mtaff_ValueOfUnitsIssuedInPeriod" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="ValueOfWarrantsIssued" id="mtaff_ValueOfWarrantsIssued" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit"/>
  <element name="WarrantsExercisePrice" id="mtaff_WarrantsExercisePrice" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WarrantsForfeitureRate" id="mtaff_WarrantsForfeitureRate" type="num:percentItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WasamacNsrMember" id="mtaff_WasamacNsrMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageExercisePriceOfUnderwritersWarrantsIssued" id="mtaff_WeightedAverageExercisePriceOfUnderwritersWarrantsIssued" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageExercisePriceOfWarrantsExercised" id="mtaff_WeightedAverageExercisePriceOfWarrantsExercised" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageExercisePriceOfWarrantsExpired" id="mtaff_WeightedAverageExercisePriceOfWarrantsExpired" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageExercisePriceOfWarrantsIssued" id="mtaff_WeightedAverageExercisePriceOfWarrantsIssued" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageExercisePriceOfWarrantsOutstanding" id="mtaff_WeightedAverageExercisePriceOfWarrantsOutstanding" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageFairValueOfRestrictedShareUnitsGranted" id="mtaff_WeightedAverageFairValueOfRestrictedShareUnitsGranted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WeightedAverageFairValueOfWarrants" id="mtaff_WeightedAverageFairValueOfWarrants" type="num:perShareItemType" abstract="false" xbrli:periodType="instant" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WestTimminsExtensionPropertiesMember" id="mtaff_WestTimminsExtensionPropertiesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="WharfAcquisitionMember" id="mtaff_WharfAcquisitionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
  <element name="ZarumaGoldMineMember" id="mtaff_ZarumaGoldMineMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" nillable="true"/>
</schema>
