Amount of aggregate warrants to purchase.

No definition available.

Name:	mtal_AggregateAmountOfWarrantsToPurchase
Namespace Prefix:	mtal_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Amount of maximum borrowing capacity of related party promissory note.

+ References

No definition available.

+ Details

Name:	mtal_MaximumBorrowingCapacityOfRelatedPartyPromissoryNote
Namespace Prefix:	mtal_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
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_BusinessAcquisitionAxis=mtal_ShareSaleAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=mtal_ConvertibleNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) - USD ($)	Apr. 13, 2022	Mar. 31, 2022	Mar. 17, 2022	Dec. 31, 2021
Class A Ordinary Shares
Subsequent Event [Line Items]
Common shares, par value, (per share)		$ 0.0001		$ 0.0001
Share Sale Agreement (the "SSA")
Subsequent Event [Line Items]
Common shares, par value, (per share)			$ 0.0001
Subsequent Event [Member] \| Class A Ordinary Shares
Subsequent Event [Line Items]
Common shares, par value, (per share)	$ 0.0001
Price of warrant	1.50
Share Price	$ 11.50
Subsequent Event [Member] \| Convertible Note [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity of related party promissory note	$ 1,200,000
Aggregate into warrants to purchase	$ 1,500,000