Price per share or per unit of warrants or rights outstanding.

No definition available.

Name:	mtal_ClassOfWarrantOrRightPriceOfWarrantsOrRights
Namespace Prefix:	mtal_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The period of time which must elapse after completion of a business combination before the Sponsor can transfer, assign or sell any Founder Shares unless other specified conditions are met.

+ References

No definition available.

+ Details

Name:	mtal_ThresholdPeriodForNotToTransferAssignOrSellAnySharesOrWarrantsAfterCompletionOfInitialBusinessCombination
Namespace Prefix:	mtal_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfWarrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsidiarySaleOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=mtal_PrivatePlacementWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Private Placement (Details) - USD ($)			3 Months Ended
Private Placement (Details) - USD ($)	Sep. 03, 2021	Aug. 02, 2021	Mar. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Number of shares per warrant			0.361
Exercise price of warrant	$ 11.50	$ 11.50
Class A Ordinary Shares
Subsidiary, Sale of Stock [Line Items]
Number of warrants to purchase shares issued	14,373,564	14,373,564
Class A Ordinary Shares \| Private Placement Warrants
Subsidiary, Sale of Stock [Line Items]
Price of warrants		$ 11.50
Number of shares per warrant		1
Private Placement.
Subsidiary, Sale of Stock [Line Items]
Number of warrants to purchase shares issued	201,971
Price of warrants	$ 1.50
Aggregate purchase price	$ 302,956
Number of shares per warrant	1
Exercise price of warrant	$ 11.50
Private Placement. \| Private Placement Warrants
Subsidiary, Sale of Stock [Line Items]
Number of warrants to purchase shares issued		5,333,333
Price of warrants		$ 1.50
Aggregate purchase price		$ 8,000,000
Private Placement. \| Class A Ordinary Shares \| Private Placement Warrants
Subsidiary, Sale of Stock [Line Items]
Threshold Period For Not To Transfer, Assign Or Sell Any Shares Or Warrants After Completion Of Initial Business Combination			30 days