Represents amount of cash and equity proceeds from sale of subsidiary.

No definition available.

Name:	thmg_CashAndEquityProceedsFromSaleOfSubsidiary
Namespace Prefix:	thmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents amount of equity proceeds from sale of subsidiary.

+ References

No definition available.

+ Details

Name:	thmg_EquityProceedsFromSaleOfSubsidiary
Namespace Prefix:	thmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents number of shares received.

+ References

No definition available.

+ Details

Name:	thmg_NumberOfSharesReceived
Namespace Prefix:	thmg_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

It represents number of stock options Included in diluted earning per share.

+ References

No definition available.

+ Details

Name:	thmg_NumberOfStockOptionsIncludedInDilutedEarningPerShare
Namespace Prefix:	thmg_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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:	thmg_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems
Namespace Prefix:	thmg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Current portion of reclamation reserve to restore a mining or drilling site to the condition agreed upon within the mining or drilling contract.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=124098289&loc=d3e6911-107765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccruedReclamationCostsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

+ Details

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow associated with the amount received from the sale of a business segment or subsidiary or sale of an entity that is related to it but not strictly controlled during the period (for example, an unconsolidated subsidiary, affiliate, joint venture or equity method investment).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3179-108585

+ Details

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

- Details

Name:	srt_OwnershipAxis=thmg_OwyheeGoldTrustLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=thmg_BemetalsOptionAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=thmg_SouthMountainMinesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=thmg_BemetalsUsaCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Summary of Significant Accounting Policies and Business Operations (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 27, 2019	Dec. 31, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Accrued reclamation costs		$ 65,000	$ 65,000
Number of stock options excluded in diluted earning per share		3,355,000
Number of stock options included in diluted earning per share			5,707,000
Owyhee Gold Trust, LLC [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of ownership interest		75.00%
Ownership percentage by noncontrolling owners		25.00%
BeMetals Option Agreement [Member] \| South Mountain Mines, Inc [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Percentage of ownership interest	100.00%
BeMetals Option Agreement [Member] \| BeMetals USA Corp [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares received	10,000,000
Cash and equity proceeds from sale of subsidiary	$ 1,350,000
Cash received	1,100,000
Shares exchanged for common stock	$ 250,000