Components of equity [axis] Issued capital [member] Contributed Surplus [Member] Reserve of share-based payments [member] Reserve For Warrants [member] Accumulated deficit [member] Shareholders' equity [member] Non-controlling interests [member] Classes of other provisions [axis] Tanzanian V A T [Member] TRA [Member] Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Gross carrying amount [member] Classes of property, plant and equipment [axis] Exploration And Evaluation Expenditures [Member] Mining property [member] Processing Plant And Related Infrastructure [Member] Machinery [member] Rightofuse Asset [Member] Other [Member] Accumulated depreciation and amortisation [member] Total [Member] Buckreefs [Member] Value Added Tax [Member] Range [axis] Bottom of range [member] Top of range [member] Classes of share capital [axis] Derivative Warrant Liabilities [Member] Funding arrangements of defined benefit plans [axis] Omnibus Equity Incentive Plan [Member] Types of share-based payment arrangements [axis] Stock Options [Member] Restricted Stock Unit [Member] Canadian Dollars Denominated Stock Options [Member] Ranges of exercise prices for outstanding share options [axis] Range 1 [Member] Range 2 [Member] Range 3 [Member] Stock Options 1 [Member] Range 4 [Member] Range 5 [Member] Segments [axis] Buckreef [Member] Directors [Member] Common Share [Member] Tanzania [Member] Major customers [axis] One Customer [Member] Canada [Member] Mineral Property Plant And Equipment [Member] Cover [Abstract] Document Type Amendment Flag Amendment Description Document Registration Statement Document Annual Report Document Quarterly Report Document Transition Report Document Shell Company Report Document Shell Company Event Date Document Period Start Date Document Period End Date Document Fiscal Period Focus Document Fiscal Year Focus Current Fiscal Year End Date Entity File Number Entity Registrant Name Entity Central Index Key Entity Primary SIC Number Entity Tax Identification Number Entity Incorporation, State or Country Code Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Three Entity Address, City or Town Entity Address, State or Province Entity Address, Country Entity Address, Postal Zip Code Country Region City Area Code Local Phone Number Extension Written Communications Soliciting Material Pre-commencement Tender Offer Pre-commencement Issuer Tender Offer Title of 12(b) Security No Trading Symbol Flag Trading Symbol Security Exchange Name Title of 12(g) Security Security Reporting Obligation Annual Information Form Audited Annual Financial Statements Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Elected Not To Use the Extended Transition Period Document Accounting Standard Other Reporting Standard Item Number Entity Shell Company Entity Public Float Entity Bankruptcy Proceedings, Reporting Current Entity Common Stock, Shares Outstanding Documents Incorporated by Reference [Text Block] Statement of financial position [abstract] Assets Current assets Cash Amounts receivable Prepayments and other assets Inventories Total current assets Other long-term receivables Mineral property, plant and equipment Total assets Liabilities Current liabilities Amounts payable and accrued liabilities Income tax payable Current portion of deferred revenue Current portion of lease liabilities Current portion of borrowings Derivative financial instrument liabilities Total current liabilities Lease liabilities Deferred income tax liability Borrowings Provision for reclamation Total liabilities Equity Share capital Contributed surplus Share-based payments reserve Warrants reserve Accumulated deficit Equity attributable to shareholders Non-controlling interest Total equity Total equity and liabilities Profit or loss [abstract] Revenue Cost of sales Production costs Royalty Depreciation Total cost of sales Gross profit General and administrative expenses Change in fair value of derivative financial instruments Foreign exchange gains (losses) Interest and other expenses Income before tax Income tax expense Net income (loss) and comprehensive income (loss) Net income (loss) and comprehensive income (loss) attributable to: Shareholders Non-controlling interest Basic (loss) earnings per share Diluted (loss) earnings per share Statement of changes in equity [table] IfrsStatementLineItems [Line Items] Beginning balance, value Beginning balance, shares Shares issued for share-based payments (Note 15) Shares issued for share-based payments, shares Share-based compensation expense (Note 15) Shares issued for cash (Notes 14 and 15) Shares issued for cash, shares Stock options exercised (Notes 14 and 15) Stock options exercised, shares Warrants exercised (Notes 14 and 15) Warrants exercised, shares Transfer from warrants reserves (Note 16) Transfer from stock option reserves (Note 15) Fees paid to brokers (Notes 14 and 15) Witholding tax impact on share-based payments Net (loss) income for the period Ending balance, value Ending balance, shares Statement of cash flows [abstract] Operating Net income (loss) Adjustments for items not involving cash: Non-cash items Changes in non-cash working capital: Increase in amounts receivable Increase in inventories Decrease (increase) in prepaid and other assets (Decrease) increase in amounts payable and accrued liabilities Increase (decrease) in income tax payable Decrease (increase) in other long-term receivables Cash provided by operating activities Investing Exploration and evaluation assets and expenditures Purchase of mineral property, plant and equipment Cash used in investing activities Financing Borrowings Financing costs paid Proceeds from warrants exercised net of fees Proceeds from stock options exercised Proceeds from shares issued for cash Withholding taxes on settlement of share-based payments Lease payments Cash (used in) provided by financing activities Net increase (decrease) in cash Cash and cash equivalents at beginning of the period(1) Exchange gain on cash and cash equivalents Cash and cash equivalents at end of the period(1) Taxes paid in cash Interest paid on leases Nature Of Operations Nature of operations Notes and other explanatory information [abstract] Basis of preparation Material Accounting Policies Judgements And Estimates Material accounting policies, judgements and estimates Amounts Receivable Amounts receivable Prepayments and other assets Inventories Mineral Property Plant And Equipment Mineral property, plant and equipment Income Tax Income tax Disclosure of insurance contracts [text block] Deferred revenue Lease Liabilities Lease liabilities Borrowings Derivative Financial Instrument Liabilities Derivative financial instrument liabilities Earnings (loss) per share Disclosure of share capital, reserves and other equity interest [text block] Share Capital Share-based payments reserve Warrants Reserve Warrants reserve Non-controlling interest Related Party Transactions Related party transactions General and administrative expenses Interest And Other Expenses Interest and other expenses Financial instruments Disclosure of entity's operating segments [text block] Segmented information Commitments and contingencies Non-cash Items Non-cash items Schedule of amounts receivables Schedule of prepayments and other assets Schedule of inventory Schedule of property, plant and equipment Schedule of components of income tax expenses Schedule of deferred revenue liability Schedule of carrying amounts of lease liabilities Schedule of statement of income and comprehensive income Schedule of lease commitments Schedule of borrowings Schedule of derivative warrant liabilities Schedule of earnings (loss) per share Schedule of continuity of outstanding stock options Schedule of options to purchase common shares carry exercise prices and terms to maturity Schedule of outstanding stock options Schedule of options to purchase common shares exercise prices Schedule of restricted share units Schedule of warrants reserve Schedule of non controlling interest Schedule of changes to the non-controlling interest Schedule of summarized financial information Schedule of Statement of Cash Flows Schedule of related party transactions Schedule of general and administrative expenses Schedule of interest and other expenses Schedule of financial instruments Schedule of revenue Schedule of non current assets Schedule of non cash items Receivable from precious metal sales Sales tax receivable(1) Other  Other receivables Less: Long-term portion Total amounts receivable Disclosure of other provisions [table] VAT refunds Current tax expense (income) and adjustments for current tax of prior periods Prepaid expenses Deferred financing costs Other assets Total prepayments and other assets Ore stockpile Gold in circuit Gold doré Total precious metals inventories Supplies Total inventories Disclosure of reconciliation of changes in goodwill [table] Mineral property, plant and equipment Depreciation Mineral property, plant and equipment Current income tax expense Deferred tax expense Net income tax expense Corporate income tax payable Deferred revenue Drawdown Accretion of deferred revenue Revenue recognized Deferred revenue Aggregate amount Lease Liabilities Additions Accretion of lease liabilities Lease payments Foreign exchange gain Lease Liabilities Less long term portion Lease liabilities Depreciation expense for right-of-use assets (Note 7) Accretion of lease liabilities (Note 24) Total amount Not later than one month Later than one month and not later than three months Later than three months and not later than one year Later than one year and not later than five years Total undiscounted lease commitments Right-of-use assets Current portion of borrowings Total borrowings Disclosure of detailed information about borrowings [table] Secured debt Purchase of machinery Interest rate Overdraft facility Warrant liability Gains (losses) on change in fair value of derivatives [custom:GainsLossesOnWarrantsExpiredOfDerivatives] [custom:GainsLossesOnWarrantsExercisedOfDerivatives] Warrant liability Derivative warrant liabilities Outstanding derivative warrant liabilities Net earnings (loss) attributable to shareholders Weighted average number of common shares for basic EPS(1) Effect of dilutive stock options and restricted share units (“RSU”) Weighted average number of common shares for diluted EPS(1) Issued common shares Cash proceeds Shares outstanding Disclosure of terms and conditions of share-based payment arrangement [table] Number of shares outstanding, Beginning Weighted average exercise price, beginning balance Number of share options exercised in share-based payment arrangement Weighted average exercise price, options exercised Number of shares outstanding, Ending Weighted average exercise price, ending balance Disclosure of number and weighted average remaining contractual life of outstanding share options [table] Exercise price Number of options outstanding Number of options exercisable Expiry date Remaining contractual life Weighted average exercise price per share beginning Number of stock, Options Granted Weighted average exercise price per share, Options Granted Number of stock, Options forfeited Weighted average exercise price per share, Options forfeited Number of stock, Options Exercised Weighted average exercise price per share, OptionsExercised Weighted average exercise price per share ending Exercise price Number of options outstanding Number of options exercisable Expiry date Remaining contractual life Restricted Share Units Restricted Share Units Granted Restricted Share Units Forfeited Restricted Share Units Exercised Restricted Share Units Disclosure of defined benefit plans [table] Share based compensation expense Common shares issued Share capital Number of shares issued for options Share-compensation reserves Number of warrants, beginning Weighted average exercise price per share, beginning Weighted average remaining contractual life (years) Number of warrants exercised Weighted average exercise price per share Warrants exercised Number of warrants Expired Weighted average exercise price per share, ending Number of warrants, ending Number of shares warrants exercised Weighted average exercise price Broker fees Warrants expired unexercised Warrants outstanding Balance at beginning of period Non-controlling interest’s 45% share of Buckreef’s comprehensive income Balance at end of period Depreciation Accretion expense Income tax expense Comprehensive income for the period Current assets Non-current assets Current liabilities Non-current liabilities Advances from parent, net Cash provided by operating activities Cash used in investing activities Cash used in financing activities Remuneration Share-based compensation expense Incremental withholding tax on share-based compensation paid Total directors and key management personnel Compensation expense Shares granted Directors’ fees (Note 18) Insurance Office and general Shareholder information Professional fees Salaries and benefits (Note 18) Consulting Share-based compensation expense (Notes 15 and 18) Incremental withholding tax on share-based compensation paid (Note 18) Travel and accommodation Depreciation Other Total general and administrative expenses Accretion of provision for reclamation (Note 24) Accretion of lease liabilities (Notes 10 and 24) Accretion of deferred revenue (Notes 9 and 24) Interest on borrowings Financing costs expensed Share issuance costs expensed VAT written-off Other Total interest and other expenses Financial Assets Measured at amortized cost Amounts receivable Measured at fair value through profit or loss Cash Financial Liabilities Measured at amortized cost Amounts payables and accrued liabilities Borrowings Measured at fair value through profit or loss Derivative financial instrument liabilities Disclosure of operating segments [table] Non-current assets Disclosure of major customers [table] Revenue percentage Revenue from customer Capital expenditures Depreciation Change in fair value of derivative financial instruments (Note 12) Share-based compensation expense (Note 15) Accretion of provision for reclamation Deferred income tax expense (Note 8) Accretion of lease liabilities (Note 10) Deferred revenue (Note 9) Accretion of deferred revenue (Note 9) Foreign exchange (gain)/losses Financing costs expensed (Note 5) VAT impaired Other Total non-cash items Disclosure of detailed information about property, plant and equipment [table] Amounts payable and accrued liabilities Current assets [Default Label] Assets [Default Label] Current liabilities [Default Label] Liabilities [Default Label] Equity attributable to owners of parent Equity [Default Label] Equity and liabilities Cost of sales [Default Label] Gross profit ForeignExchangesLoss Profit (loss) before tax Profit (loss), attributable to non-controlling interests Number of shares outstanding ExplorationAndEvaluationAssetsAndExpenditures Purchase of property, plant and equipment, classified as investing activities Borrowing WithholdingTaxesOnSettlementOfDividendsPaidClassifiedAsFinancingActivitiesRsus WithholdingTaxesOnSettlementOfRsus RepaymentOfLeases Increase (decrease) in cash and cash equivalents after effect of exchange rate changes Cash and cash equivalents DisclosureOfTradeAndOtherReceivableExplanatory Disclosure of prepayments and other assets [text block] Disclosure of inventories [text block] DisclosureOfMineralPropertiesAndDeferredExplorationExplanatory DisclosureOfLeaseLiabilitiesExplanatory Disclosure of borrowing costs [text block] DerivativeFinancialInstrumentLiabilitiesTextBlock Disclosure of share-based payment arrangements [text block] DescriptionOfWarrantsReserveExplanatory Disclosure of non-controlling interests [text block] DisclosureOfInterestAndOtherExpensesExplanatory NonCashItemsExplanatory TotalPreciousMetalsInventories TotalInventories PropertyPlantAndEquipments Additions other than through business combinations, property, plant and equipment DeferredRevenueNote Lease liabilities [Default Label] Other long-term employee benefits PaymentsOfLeaseLiabilities CurrentPortionOfBorrowings Warrant liability ShareOptionsWeightedAverageExericsePrice Number of share options exercised in share-based payment arrangement WeightedAverageExercisePricePerShare NumberOfOtherEquityInstrumentsGrantedInSharebasedPaymentArrangement Number of other equity instruments forfeited in share-based payment arrangement NumberOfOtherEquityInstrumentsExercisedInSharebasedPaymentArrangement NumberOfExercisePriceOutstanding NumberOfOptionsOutstanding NumberOfShareOptionsExercisablesInSharebasedPaymentArrangement NumberOfShareOptionsExpiryDateInSharebasedPaymentsArrangement WeightedAverageRemainingContractualLifeOfOutstandingsShareOptions1 NumberOfOutstandingRestrictedShareUnits ShareCapital WarrantsOutstandingAtNumberOfStockOptions WarrantsOutstandingWeightedAverageExercisePricePerShare DepreciationExpenses DepreciationsExpenses OthersGeneralAndAdministrativeExpense OtherInterestExpenses Financial assets available-for-sale Cash equivalents FinancialLiabilitiesBorrowings Derivative financial liabilities Non-current assets [Default Label] Depreciation expense ChangeInFairValueOfDerivativeFinancialInstrumentsNote9 SharebasedCompensationExpense Other [Default Label] IncreaseDecreaseInAccountsPayableAndAccruedLiabilitie