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  <xsd:element name="RoyaltyEarnedOnTonsShippedOrDeemedShippedPercentage" id="msb_RoyaltyEarnedOnTonsShippedOrDeemedShippedPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BonusRoyaltyPercentage" id="msb_BonusRoyaltyPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RoyaltyBonusesPriceAboveAdjustedThresholdPricePerTon" id="msb_RoyaltyBonusesPriceAboveAdjustedThresholdPricePerTon" type="srt-types:perUnitItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BonusRoyaltyGrossProceedsPercentage" id="msb_BonusRoyaltyGrossProceedsPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RoyaltyBonusesAdjustedThresholdPricePerTon" id="msb_RoyaltyBonusesAdjustedThresholdPricePerTon" type="srt-types:perUnitItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="Rule10b51ArrModifiedFlag" id="msb_Rule10b51ArrModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NonRule10b51ArrModifiedFlag" id="msb_NonRule10b51ArrModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
</xsd:schema>
