Detour Lake Operation

Ontario, Canada
NI 43-101 Technical Report

CERTIFICATE OF QUALIFIED PERSON

I, Steven Gray, P. Geo. am employed as Exploration Superintendent with Kirkland Lake Gold Ltd, with an street address at Royal Bank Plaza, South Tower 200 Bay Street, Suite 2800 Toronto, Ontario, M5J 2J1 Canada.

I am a Professional Geologist with the Professional Geoscientists of Ontario, APGO Membership #1580.  I graduated from Carleton University (Canada) in 1992 with a bachelor's degree in Geology.

I have practiced my profession for 29 years. I have been directly involved in the planning, execution, and management of the Exploration Program at Detour Lake Mine.  My mining and exploration experience includes senior positions with Placer Dome Canada Inc, Hudson Bay Mining and Smelting Inc., Chief Geologist positions with Kirkland Lake Gold Inc, Richmont Mines Inc, and Primero Mining Ltd and Vice President of Exploration for Northern Sphere Mining.  I have consulted for numerous exploration and mining companies assisting with projects in Canada and abroad.  I have exploration and drill data experience, including supervision, design and execution of drill programs, assay programs and quality assurance and quality control checks on drill and assay data, construction of geological models, and database verification.  My mining expertise includes serving as Mine Manager for URSA Major Minerals Inc. and Industrial Minerals Inc., managing the development and extraction of base metal, precious metal, and industrial minerals.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

My most recent site visit was on August 26, 2021.

I am responsible for Sections 1.1, 1.2, 1.5 to 1.8, 1.25; Section 2; Section 6; Section 7; Section 8; Section 9; Section 10; Section 11; Section 12; Sections 25.1, 25.3, 25.4; and Section 27 of the technical report.

I have been involved with the Detour Lake Mine for one year and four months in my role as Exploration Superintendent working out of the Timmins/Kirkland Lake Offices, spending time at site monthly.  I also worked onsite for five years, from 1992-1996, serving as an underground mine geologist for Placer Dome Canada.

I have read NI 43-101, and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated:  19 October, 2021

"Signed" 

Steven Gray, P.Geo.

CERTIFICATE OF QUALIFIED PERSON

I, Andre Leite, P. Eng. am employed as Vice President Technical Services with Kirkland Lake Gold Ltd, with an address at Royal Bank Plaza, South Tower 200 Bay Street, Suite 2800 Toronto, Ontario, M5J 2J1 Canada.

This certificate applies to the technical report titled “Detour Lake Operation, Ontario, Canada, NI 43-101 Technical Report” that has an effective date of 26 July, 2021, and an amended and restated date of 19 October, 2021 (the “technical report”).

I am a Professional Engineer with Professional Engineers Ontario, license number 100153687; a chartered professional member of the Australasian Institute of Mining and Metallurgy (MAusIMM(CP)), member number 301888.  I graduated from McGill University (Canada) in 2008 with a Master's Degree in Mining Engineering and from Universidade Federal de Minas Gerais in 2004 with a Bachelor's Degree in Mining Engineering.

I have practiced my profession for 17 years.  I have been directly involved in the mineral resource modelling for the Detour Main Pit and have reviewed in detail the mineral resource modelling for the North pit, West Detour and 58N deposits. I have also participated in life of mine planning. I have two years of experience as the Detour Lake Mine Technical Service Manager. Prior to that I held the positions of Technical Service Manager Vale Base Metals Asia Pacific, responsible for mineral resource and mineral reserve estimates for Vale Base Metal operations in the region; Principal Mine Engineer Vale Base Metals Global, leading the initiatives associated with corporate governance, technical services and technology and innovation for the Base Metals business with a major focus on their open pit operations; as mineral resource and mineral reserve specialist with the Inco (later Vale) Mineral Resources and Mineral Reserves team supporting all operations globally with mineral resource modelling, mine design, mine production planning and mineral reserve definition.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

My most recent site visit was on September 13, 2021.

I am responsible for  Sections 1.1 to 1.4, 1.8, 1.10.1, 1.10.3, 1.11 to 1.14, 1.16, 1.18, 1.23 to 1.25; Section 2; Section 3; Section 4; Section 5; Section 12; Sections 14.1, 14.2, 14.4 to 14.7; Section 15; Section 16; Section 18; Section 19; Section 23; Section 24; Sections 25.1, 25.2, 25.6 to 25.8. 25.10, 25.12, 25.16, 25.17; Sections 26.1, 26.2, Section 27, and Appendix A of the technical report.

I am not independent of Kirkland Lake Gold as independence is described in Section 1.5 of NI 43-101.

I have been involved with the Detour Lake Mine for two years in my role as a Technical Service Manager working at site.  I have previously co-authored a technical report on the Detour Lake Operation:

• Leite, A., Dupont, J.F., Raizman, V., and Fournier, P.A., 2020:  Detour Lake Operations, Ontario, Canada, NI 43-101 Technical Report:  technical report prepared for Kirkland Lake Gold, effective date 30 December, 2020.

I have read NI 43-101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated:  19 October, 2021

"Signed" 

Andre Leite, P.Eng.

CERTIFICATE OF QUALIFIED PERSON

I, Juan Figueroa, P.Geo., am employed as the Manager, Mineral Resource with Kirkland Lake Gold Ltd, with a street address at 115 Jubilee Ave., East, Timmins, Ontario, P4N 5W4, Canada.

This certificate applies to the technical report titled “Detour Lake Operation, Ontario, Canada, NI 43-101 Technical Report” that has an effective date of 26 July, 2021 and an amended and restated date of 19 October, 2021 (the “technical report”).

I am a member in good standing of the Professional Geoscientists of Ontario (PGO licence No. 2200).  I graduated from Laurentian University (Canada) in 1995 with a Master's Degree in Science and from Universidad Central del Ecuador in 1988 with a Bachelor's Degree in Engineering Geology.

I have practiced my profession continuously as a geologist for 32 years and I have worked as a Resource Geologist for 12 years being employed as a Senior Resource Geologist by Lake Shore Gold, Primero Mining, Tahoe Resources, and Pan American Silver.  I have experience with various mineral deposit types, Mineral Resource estimation techniques, and the preparation of technical reports.  I have been directly involved with the modeling of geology and mineral resource domains for the Saddle and West Detour Areas and have reviewed in detail the mineral resource estimation for the Saddle and West Detour deposits.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43- 101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

My most recent site visit was from July 21-23, 2020.

I am responsible for Sections 1.1, 1.2, 1.8, 1.10.2, 1.10.3, 1.11, 1.25; Sections 2.1 to 2.6; Sections 14.1, 14.3 to 14.7; and Sections 25.1, 25.6, 25.16; and Section 27 of the technical report.

I am not independent of Kirkland Lake Gold as independence is described in Section 1.5 of NI 43-101.

I have been directly involved with Detour Lake Mine for 16 months in my role as Manager of Mineral Resources.

I have read NI 43-101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated: 19 October, 2021

"Signed"

Juan Figueroa, P.Geo.

CERTIFICATE OF QUALIFIED PERSON

I, Jean-Francois Dupont (P. Eng., OIQ) am employed as the Detour Lake Mine Chief Metallurgist with Kirkland Lake Gold Ltd, with an address at 1B First Avenue, Cochrane, Ontario.

This certificate applies to the technical report titled “Detour Lake Operation, Ontario, Canada, NI 43-101 Technical Report” that has an effective date of 26 July, 2021 and an amended and restated date of 19 October, 2021 (the “technical report”).

I am a Professional Engineer, member of L'Ordre Des Ingénieurs du Québec, license number 117145.  I graduated from Laval University (Canada) in 1996 with a Bachelor's Degree in Mining Engineering, majoring in mineral processing.

I have practiced my profession for 24 years.  I joined Detour Gold Corporation, a predecessor company to Kirkland Lake Gold Ltd. in 2011 and was directly involved in the engineering, construction and commissioning of the Detour Lake Mine processing plant.  I have worked in the Detour Lake Mine processing plant for eight years.  I have also participated in the elaboration of life-of-mine plans.  Prior to that, I held various positions with Barrick Gold for 14 years including five years at the Corporate office as Comminution Metallurgist.  This position gave me exposure to the 19 processing plants Barrick Gold had at the time. 

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

I am directly employed at the Detour Operation, and have been since 2011.  This familiarity with the operations serves as my personal inspection for the purposes of the technical report.

I am responsible for Sections 1.1, 1.2, 1.9, 1.15; Sections 2.1 to 2.4, 2.6; Section 13; Section 17; Sections 25.1, 25.5, 25.9; and Section 27 of the technical report.

I am not independent of Kirkland Lake Gold Ltd, as independence is described by Section 1.5 of NI 43-101.

I have been involved with the Detour Operation since 2011 during engineering, construction, commissioning, and operations of the process plant.  I have previously co-authored a technical report on the Detour Lake Operation:

• Leite, A., Dupont, J.F., Raizman, V., and Fournier, P.A., 2020:  Detour Lake Operations, Ontario, Canada, NI 43-101 Technical Report:  technical report prepared for Kirkland Lake Gold, effective date 30 December, 2020.

I have read NI 43-101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated:  19 October, 2021

"Signed"

J-F Dupont, P. Eng (OIQ)

CERTIFICATE OF QUALIFIED PERSON

I, Veronika Raizman, P. Geo. am employed as a Manager for Reclamation and Geochemistry, with Kirkland Lake Gold Inc., with an address at Royal Bank Plaza, South Tower 200 Bay Street, Suite 2800 Toronto, Ontario, M5J 2J1 Canada.

This certificate applies to the technical report titled “Detour Lake Operation, Ontario, Canada, NI 43-101 Technical Report” that has an effective date of 26 July,  2021, and an amended and restated date of 19 October, 2021 (the “technical report”).

I am a Professional Geoscientist registered with the Professional Geoscientists of Ontario (Membership #2563). I graduated from the University of Toronto with a Ph.D. in Earth Sciences (2015), a M.Sc. in Geology (2011), and a H.B.Sc. in Environmental and Physical Geography (2010).

I have practiced my profession for 10 years. Prior to joining the Detour Lake Mine in 2016, I served as a geochemist with SRK Consulting Ltd., where I gained experience in the prediction and management of acid rock drainage and metal leaching during all phases of the mining cycle, as well as mine waste characterization using static, kinetic, and field testing programs. At the Detour Lake Mine, I have previously served in multiple roles, including Environmental Specialist; Geochemistry, Research and Closure Coordinator; and Senior Advisor for Mine Closure Planning and Geochemistry. My duties have supported, but not been limited to, 1) environmental permitting, reporting and compliance, including Indigenous consultation; 2) management of geochemical monitoring programs, including water quality (i.e. effluent and receiving environment) and mine wastes (i.e. waste rock and tailings); and 3) planning and execution of progressive reclamation and mine closure activities.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

I have worked at Detour Lake mine site, and this familiarity with the operation serves as my personal inspection.

I am responsible for Sections 1.1, 1.2, 1.17; Sections 2.1 to 2.4, 2.6; Section 20; Sections 25.1, 25.11; and Section 27 of the technical report.

I am not independent of Kirkland Lake Gold as independence is described in Section 1.5 of NI 43-101.

I was based at the Detour Lake Mine for four years and five months, followed by my current role as Manager for Reclamation and Geochemistry at the Kirkland Lake Gold Inc. Toronto corporate office, where I have served for a year.  I have previously co-authored a technical report on the Detour Lake Operation:

• Leite, A., Dupont, J.F., Raizman, V., and Fournier, P.A., 2020:  Detour Lake Operations, Ontario, Canada, NI 43-101 Technical Report:  technical report prepared for Kirkland Lake Gold, effective date 30 December, 2020.

I have read NI 43-101, and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated:  19 October, 2021

"Signed" 

Veronika Raizman, P.Geo.

CERTIFICATE OF QUALIFIED PERSON

I, Paul Andrew Fournier, P.Eng., am employed as a Manager, Cost Accounting at the Corporate Office of Kirkland Lake Gold Ltd, with an address at Royal Bank Plaza, South Tower 200 Bay Street, Suite 2800 Toronto, Ontario, M5J 2J1, Canada.

This certificate applies to the technical report titled “Detour Lake Operation NI 43-101 Technical Report” that has an effective date of 26 July, 2021 and an amended and restated date of 19 October, 2021 (the “technical report”).

I am a Professional Engineer with Professional Engineers Ontario, license number 100218548.  I graduated from McGill University (Canada) in 2011 with a Bachelor of Materials Engineering degree.  I passed the Level III Exam of the CFA® Program of the CFA Institute in 2021.

I have practiced my profession since graduation.  I have seven years of experience in process and metallurgical engineering in mining and metals, including four years with the processing plant at the Detour Lake Mine.  This experience includes five years of metals accounting, cost estimation, production and economic forecasting.  I have two years of experience in financial analysis specifically for the Detour Lake Mine.  As part of my role with Kirkland Lake Gold Ltd, I prepared the financial model for the Detour Lake Mine consolidated budget for 2020 and 2021.  I have intimate knowledge of the cost model for the Detour Lake Mine through experience in budgeting, forecasting, monthly reporting, and variance analysis.

As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101) for those sections of the technical report that I am responsible for preparing.

My latest personal inspection of the Detour Lake Mine property was a 14-day rotation from July 2-15, 2020.

I am responsible for Sections 1.1, 1.2, 1.19, 1.20, 1.21, 1.22, 1.23; Sections 2.1 to 2.6; Section 21, Section 22, Sections 25.1, 25.13, 25.14, 25.15, 25.17, and Section 27 of the technical report.

I am not independent of Kirkland Lake Gold Ltd as I am currently employed as Manager, Cost Accounting.

I have been involved with the Detour Gold Mine since 2014, first with the process plant, and then as a financial analyst.

I have read NI 43-101 and the sections of the technical report for which I am responsible have been prepared in compliance with that Instrument.

As of the effective date of the technical report, to the best of my knowledge, information and belief, the sections of the technical report for which I am responsible contain all scientific and technical information that is required to be disclosed to make the technical report not misleading.

Dated:  19 October, 2021

"Signed" 

Paul Andrew Fournier, P.Eng.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Cautionary Statements

Cautionary Notes

Forward-Looking Information

This Technical Report contains certain forward-looking information and forward-looking statements, as defined in applicable securities laws (collectively referred to herein as "forward-looking statements"). Forward-looking statements reflect current expectations or beliefs regarding future events or Kirkland Lake Gold Ltd.'s (Kirkland Lake Gold or the Company) future performance.  All statements other than statements of historical fact are forward-looking statements. Often, but not always, forward-looking statements can be identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "continues", "forecasts", "projects", "predicts", "intends", "anticipates", "targets", or "believes", or variations of, or the negatives of, such words and phrases or state that certain actions, events or results "may", "could", "would", "should", "might" or "will" be taken, occur or be achieved.

Forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause actual results, performance or achievements to be materially different from any of its future results, performance or achievements expressed or implied by forward-looking statements. These risks, uncertainties and other factors include, but are not limited to, assumptions and parameters underlying the life of mine update not being realized, a decrease in the future gold price, discrepancies between actual and estimated production, discrepancies related to the impact of various capital projects and the anticipated benefits therein, required capital investments; estimates of net present value and internal rate of returns; the accuracy of Mineral Reserve and Mineral Resource estimates, production estimates and capital and operating cost estimates and the assumptions on which such estimates are based; market competition; ongoing relations with employees and impacted communities changes in costs (including labour, supplies, fuel and equipment), changes to tax rates, environmental compliance and changes in environmental legislation and regulation, exchange rate fluctuations, general economic conditions and other risks involved in the gold exploration and development industry, as well as those risk factors discussed in the Technical Report. Such forward-looking statements are also based on a number of assumptions which may prove to be incorrect, including, but not limited to, assumptions about the following: the availability of financing for exploration and development activities; operating and capital costs; the Company's ability to attract and retain skilled staff; sensitivity to metal prices and other sensitivities; the supply and demand for, and the level and volatility of the price of gold; the supply and availability of consumables and services; the exchange rates of the Canadian dollar to the U.S. dollar; energy and fuel costs; the accuracy of reserve and resource estimates and the assumptions on which the reserve and resource estimates are based; market competition; ongoing relations with employees and impacted communities and general business and economic conditions. Accordingly, readers should not place undue reliance on forward-looking statements. The forward-looking statements contained herein are made as of the date hereof, or such other date or dates specified in such statements.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

All forward-looking statements in this Technical Report are necessarily based on opinions and estimates made as of the date such statements are made and are subject to important risk factors and uncertainties, many of which cannot be controlled or predicted. Kirkland Lake Gold and the Qualified Persons who authored the Technical Report undertake no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law.

Non-IFRS Financial Performance Measures

Kirkland Lake Gold has included certain non-IFRS measures in this document. The Company believes that these measures, in addition to conventional measures prepared in accordance with IFRS, provide investors an improved ability to evaluate the underlying performance of the Company. The non-IFRS measures are intended to provide additional information and should not be considered in isolation or as a substitute for measures of performance prepared in accordance with IFRS. These measures do not have any standardized meaning prescribed under IFRS, and therefore may not be comparable to other issuers.

Free Cash Flow Before & After Tax

In the gold mining industry, free cash flow is a common performance measure with no standardized meaning. Kirkland Lake Gold calculated free cash flow before taxes by deducting site operating costs, royalties and first nations payments, changes in inventory, capital expenditures, reclamation expenditures, and lease payments from net revenues and changes in working capital. Free cash flow after taxes is calculated by deducting tax expenses from free cash flow before taxes. 

Kirkland Lake Gold discloses free cash flow before and after tax as it believes the measure provides valuable assistance to investors and analysts in evaluating the Company's ability to generate cash flow after capital investments and build the cash resources of the Company. The most directly comparable measure prepared in accordance with IFRS is net cash provided by operating activities less net cash used in investing activities.

Operating Unit Costs

Kirkland Lake Gold reports the following operating unit costs:

• Mining operating unit cost (C$/t ex-pit): calculated as mining operating costs excluding adjustment for deferred stripping divided by total tonnes mined (ore + waste).

• Operating unit cost per tonne (C$/t milled): calculated as operating costs divided by total tonnes milled. This is calculated for the different components of operating cost. Operating costs include mite site operating costs such as mining, processing, and site administration, as well as adjustments for deferred stripping, royalties, and changes in inventory.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

• Operating unit cost per ounce (C$/t oz sold): calculated as operating costs per ounce on a gross gold sales basis, where gross gold sales represent gold production after adjustment for changes in gold-in-circuit and dore inventory.

Kirkland Lake Gold discloses operating costs and operating unit cost per tonne and per ounce as it believes the measures provide valuable assistance to investors and analysts in evaluating the Company's operational performance and ability to generate cash flow. The most directly comparable measure prepared in accordance with IFRS is total production expenses. Operating cash costs and operating cash cost per ounce of gold should not be considered in isolation or as a substitute for measures prepared in accordance with IFRS.

Operating Margin

The operating margin represents net revenue after site operating costs, royalties and First Nations payments, and changes in inventory. Operating margin is an indicator of the Company's ability to generate liquidity by producing operating cash flow to fund working capital needs, service debt obligations, and fund capital expenditures.

Operating Cash Costs and Operating Cash Costs per Ounce Sold

Operating cash costs and operating cash cost per tonne and per ounce sold are non-IFRS measures. In the gold mining industry, these metrics are common performance measures but do not have any standardized meaning under IFRS. Operating cash costs include mine site operating costs such as mining, processing and administration, but exclude royalty expenses, depreciation and depletion and share based payment expenses and reclamation costs. Operating cash cost per ounce sold is based on ounces sold and is calculated by dividing operating cash costs by volume of gold ounces sold.

Kirkland Lake Gold discloses operating cash costs and operating cash cost per tonne and per ounce as it believes the measures provide valuable assistance to investors and analysts in evaluating the Company's operational performance and ability to generate cash flow. The most directly comparable measure prepared in accordance with IFRS is total production expenses. Operating cash costs and operating cash cost per ounce of gold should not be considered in isolation or as a substitute for measures prepared in accordance with IFRS.

AISC and AISC per Ounce Sold

All-in sustaining costs (AISC) and AISC per ounce are non-IFRS measures. These measures are intended to assist readers in evaluating the total costs of producing gold from current operations. While there is no standardized meaning across the industry for this measure, Kirkland Lake Gold's definition conforms to the definition of AISC as set out by the World Gold Council in its guidance note dated June 27, 2013.

The Company defines AISC as the sum of operating costs (as defined and calculated above), royalty expenses, sustaining capital, corporate expenses and reclamation cost accretion related to current operations. Corporate expenses include general and administrative expenses, net of transaction related costs, severance expenses for management changes and interest income. AISC excludes growth capital expenditures, growth exploration expenditures, reclamation cost accretion not related to current operations, interest expense, debt repayment and taxes.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Sustaining and Growth Capital

Sustaining capital and growth capital are non-IFRS measures. Sustaining capital is defined as capital required to maintain current operations at existing levels. Growth capital is defined as capital expenditures for major growth projects or enhancement capital for significant infrastructure improvements at existing operations. Both measurements are used by management to assess the effectiveness of investment programs.

Working Capital

Working capital is a non-IFRS measure. In the gold mining industry, working capital is a common measure of liquidity, but does not have any standardized meaning.

The most directly comparable measure prepared in accordance with IFRS is current assets and current liabilities. Working capital is calculated by deducting accounts payables from accounts receivables, supplies inventory, and gold inventory (ore stockpiles, gold-in-circuit, and dore inventory). Working capital should not be considered in isolation or as a substitute from measures prepared in accordance with IFRS. The measure is intended to assist readers in evaluating Kirkland Lake Gold's liquidity.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table of Contents

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table of Tables

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table of Figures

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table of Appendices

Appendix A:  Mineral Claims List and Mineral Claims Location Plans

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

1.0 Summary

1.1 Introduction

Mr. Steve Gray, Mr. Andre Leite, Mr. Juan Figueroa, Mr. Jean-Francois Dupont, Dr. Veronika Raizman, and Mr. Paul Andrew Fournier prepared a NI 43-101 Technical Report (the Report) on the Detour Lake Operations (the Detour Lake Operations, Detour Lake Mine, or the Project) for Kirkland Lake Gold Ltd (Kirkland Lake Gold).  The Detour Lake Operations are located in in northeastern Ontario.

The Detour Lake Operations consist of the operating Detour Lake Main Pit, and planned open pit operations at the West Detour and North Pits.  Mineral Resources are estimated for the Detour Lake, West Detour, North Pit and Zone 58N areas.  Mineral Reserves are estimated for the Detour Lake, West Detour and North Pit areas. 

1.2 Terms of Reference

The Report supports disclosure in the news release dated 2 September, 2021, entitled "Kirkland Lake Gold Announces 10.1 Million Ounce Increase in Measured and Indicated Mineral Resources at Detour Lake Mine".

The report was refiled to address a clerical/typographic error in the Mineral Resource tables in the Report that saw certain data inadvertently pasted into wrong cells within the tables.

Units used in the report are metric units unless otherwise noted.  Monetary units are in Canadian dollars (C$) unless otherwise stated.  All ounce units refer to troy ounces.  The Report uses Canadian English.  Mineral Resources are reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves (May 2014; the 2014 CIM Definition Standards).  The Detour Lake deposit and open pit can also be referred to as the Detour Main deposit and open pit.

1.3 Property Description and Location

The Project is situated approximately 300 km northeast of Timmins and 185 km by road northeast of Cochrane.  From the town of Cochrane (population of approximately 5,000 residents), the Project is easily accessible by the Detour Lake Mine road, the northern extension of Highway 652.  The first 151 km on Highway 652 is paved surface, followed by 34 km of well-maintained gravel surfaced road to the mine site.  Road access is available year-round.  The closest major airport to the site is at Timmins, Ontario, approximately 61 km to the southeast.

The climate in the Project area is characterized by cold winters and mild summers.  The average total annual precipitation is estimated at 862 mm with approximately 30% falling as snow, and the greatest precipitation contribution occurring as rain during June through October.  The predominant wind direction is from the west.  Mining and exploration activities are conducted year-round.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Site topography is subdued with maximum local relief of approximately 30 m.  The elevation ranges from approximately 260-288 metres above sea level.  Areas of higher relief are sparsely wooded with jack pine, black and white spruce, balsam fir, trembling aspen, and white birch.  Areas that are slightly lower in relief are poorly drained and characterized by muskeg.  There is very little bedrock outcrop and much of the Project area is overlain by thick accumulations of glacial material that includes till and glaciofluvial material (poorly sorted sand with lenses of gravel). 

Numerous small streams linking elliptical lakes and ponds, generally oriented parallel to the pattern of glacial fluting.  Many small and shallow lakes are found within the Project area, the largest being Sunday Lake.

1.4 Mineral Tenure, Surface Rights, Water Rights and Royalties

On January 31, 2020, Kirkland Lake Gold completed the acquisition of Detour Gold Corporation (Detour Gold) and Detour Gold became a wholly-owned subsidiary of Kirkland Lake Gold.  On January 2, 2021, Detour Gold was amalgamated with Kirkland Lake Gold Inc., a wholly-owned subsidiary of Kirkland Lake Gold, and the amalgamated entity was renamed Kirkland Lake Gold Inc.

The 646 km² Project area forms one contiguous group of mining patents, mining leases and cell mining claims in the District of Cochrane, Ontario, with a small group of cell claims in Massicotte Township, Québec.  The mineral tenure in Ontario consists of

• 2,213 cell mining claims:  39,714 ha;

• 44 lease documents:  23,712 ha;

• 6 patent documents:  602 ha.

There are an additional 20 claims covering 549 ha in Quebec.

The patented parcels of land are the most secure form of land tenure and are subject to an annual mining tax payable to the Crown.  The patented lands are described by the legal survey of individual mining claims and surveyed mining locations.  The leasehold mining lands consist of 21-year mining leases issued for mining claims that were legally surveyed as individual mining claims or defined by the perimeter survey of groups of mining claims.  The Mining Act (Ontario) contains provisions for the renewal of 21-year mining leases.  Applications for renewal are subject to review and consent by the Ministry of Energy, Northern Development and Mines (ENDM), now renamed to Ministry of Northern Development Mines, Natural Resources and Forestry (NDMNRF).  Upon registering cell mining claims (cells) in Ontario, Kirkland Lake Gold must perform and file exploration assessment work and apply on those cells assessment work credits to maintain them in good standing.  The first unit of assessment work of $400 per 20 ha is required by the second anniversary date of the recording of the cell and an additional unit is required to be performed and filed for each year thereafter.  A claim in Québec provides the stakeholder with a two-year right to explore within the claim holdings for any mineral substance with exceptions.  After the initial two-year period claims can be renewed for an additional two-year term on certain conditions including that sufficient assessment work is performed on the claims or payment is made in lieu.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Kirkland Lake Gold has 30 leases and 10 patents totaling 18,574.442 ha of surface rights on the Detour Lake Project.  The surface rights are sufficient for all surface infrastructure and mine operation.

Kirkland Lake Gold does not exclusively hold water rights in the region.  As part of the ongoing environmental compliance Kirkland Lake Gold is required to capture all site runoff from stockpiles and the open pits. Water taking from groundwater and freshwater sources is regulated by the Ontario Ministry of Environment, Conservation and Parks (MECP) via Permits to Take Water (PTTW). The Detour Lake Mine has a number of active PTTW, which are renewed at the required regulatory frequency in order to support activities over the life-of-mine (LOM).  Since this water is required to be captured it puts the site water balance in a surplus over the LOM, providing sufficient water to be used for processing in the mill, with the excess being discharged to the environment under the permitted discharge conditions for the operations.

Certain of the claims are subject to a 2% royalty payable to Franco-Nevada Corporation.  This royalty is included in the cash flow analysis.  Other claims are subject to royalties to third-parties but these claims do not fall within the area of the estimated Mineral Resources and Mineral Reserves.  Kirkland Lake Gold has certain payments to First Nations groups in the area of the estimated Mineral Resources and Mineral Reserves; these payments are included in the economic analysis.  The Detour Lake Operations are not subject to any other back-in rights payments, agreements or encumbrances.

Exploration activities require water-taking permits to be obtained to provide the necessary water for exploration drilling activities. To date, all such permits have been granted as required. 

Current exploration liabilities consist with respect to the environment primarily consist of the potential for fuel and lubricant spills and the risk of fire during the drier months resulting from heavy equipment.

1.5 Geology and Mineralization

The Detour Lake and West Detour deposits are considered to be examples of orogenic greenstone-hosted hydrothermal lode gold deposits.

The Project is located within the northwestern portion of the Abitibi Greenstone Belt that consists of east-west-trending synclines of felsic to ultramafic volcanic rocks.  Intervening domes are cored by syn-volcanic tonalite and gabbrodiorite rocks and alternate with east-west-trending bands of late tectonic turbiditic and conglomeratic sedimentary rocks.  Most of the volcanic and sedimentary strata dip vertically and are commonly bound by abrupt, east-west-trending faults with varied dips.

In the Project area, the greenstone-granite architecture is partially aligned and disrupted along a linear, east-west-trending belt that defines the position of the Sunday Lake Deformation Zone.  Supracrustal rocks within the Project area consist of a thick sequence of mafic to ultramafic lithologies, which are predominantly volcanic in origin, and are part of the Deloro assemblage.  They occur within regional synclinal-anticlinal fold structures traced for over 30 km across the Project and are in structural contact to the south with the younger sediments of the Caopatina assemblage.  These rocks are bounded to the north and west by the Opatica basement gneissic rocks.  To the east and south, the Deloro assemblage is intruded by several large, weakly foliated granodioritic to tonalitic intrusions which are intersected by numerous local felsic to mafic dykes, sills and younger regional Proterozoic diabase dykes.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

There are two recognized episodes of gold mineralization at the Detour Lake and West Detour deposits.

The first episode consists of a wide and generally auriferous sulphide-poor quartz vein stockwork formed in the hanging wall of the Sunday Lake Deformation Zone.  The sulphide-poor quartz vein stockworks observed in the hanging wall have sub-vertical north or south dips and are parallel to a series of east-west trending high strain zones.  These veins form a weak stockwork and are boudinaged and/or folded.

The second episode is a stage of gold mineralization overprinting the early auriferous stockwork, principally in the hanging wall of the Sunday Lake Deformation Zone, with a higher sulphide content.  The sulphide-rich gold mineralization predominantly fills structural sites in deformed quartz veins, fractures and veins crosscutting the foliation fabric but also in pillow breccias and selvages.  The distribution of sulphide-rich mineralization is strongly controlled by the geometry of kinematic orientation.

The major structural feature is the 30 km-long Sunday Lake Deformation Zone, an east-west-trending, steeply north-dipping deformation corridor.  A regional east-west trending structure, the Massicotte Deformation Zone is recognized several kilometres to the south of the Sunday Lake Deformation Zone and extends for over 30 km in strike length.  It marks the southern contact between the Caopatina assemblage sedimentary rocks and the underlying Deloro assemblage volcanic rocks.  The third major structure is the Lower Detour Deformation Zone, a 30 km long, east-west-trending, and steeply south-dipping one that separates Caopatina assemblage sedimentary rocks and the underlying Deloro assemblage volcanic rocks.  The youngest structures are a series of 120-145° trending faults, which are locally intruded by Proterozoic-age diabase dykes.  Two east-trending synform-antiform pairs are developed in the volcanic assemblage, the North Walter Lake Synform and the Airstrip Antiform.

Mineralization at Detour Lake has a strike extent of 3.75 km, a width of 1.35 km, and an approximate elevation range of 800 m.  Mineralization is hosted within a broad assemblage of mafic volcanic rocks with an overall east-west trend.  The bulk of the mineralization within this corridor is concentrated along a highly-strained corridor of a moderate to strong potassic alteration envelope at the contacts between pillowed and massive mafic flows.  Gold is associated with quartz-carbonate-pyrite-pyrrhotite ± tourmaline veins and/or disseminated to very local semi-massive sulphides in hydrothermally-altered wall rocks.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The West Detour deposit has a strike extent of 3.1 km, a width of 2.2 km, and an approximate elevation range of 1 km.  Generally, the gold zones occur in a variety of structural settings and several rock types including massive to pillowed tholeiitic basalt flows, variably deformed-altered basaltic to peridotitic komatiite units, cherty tuffs, gabbro and deformed felsic to intermediate dykes.  Mineralized lenses vary from 5-50 m in true width.  Gold is associated with pyrite, pyrrhotite, and rarely chalcopyrite.

The Zone 58N deposit has an east-west strike length of 450 m, extends from surface to a depth of 800 m, and the mineralized system remains open at depth.  Gold mineralization in Zone 58N is within the southern portion of a feldspar porphyry intrusion, and hosted by a swarm of plagioclase-phyric tonalitic dykes that intrude mafic rocks of the Deloro assemblage.  Gold is found within and at the margins of quartz ± tourmaline ± carbonate stockwork-type veins that infill areas of brittle deformation.  Visible gold occurs in nearly every drill hole that intersects mineralization and is also present as micro-inclusions within pyrite grains, or intergrown with bismuth-tellurides.

Exploration potential remains in the area where Mineral Resources are estimated.  The Main and Quartz Hangingwall Zones in the Detour Lake deposit remain open at depth.  The West Detour mineralization has potential be extended both to the west and at depth.  The North Pit also has potential for depth and along strike extension, as does the 58N Zone and Zone 75.

1.6 History

Companies who have had Project involvement prior to Kirkland Lake Gold's Project interest include Amoco Canada Petroleum Company Ltd. (Amoco), Campbell Red Lake Mines (Campbell), Dome Mines Ltd. (Dome), Placer Dome Inc. (Placer Dome), Pelangio-Larder Mines Limited (Pelangio-Larder), Franco-Nevada Mining Company Limited (Franco-Nevada), Marl Resources Corp. (Marl Resources), Pelangio Mines Inc. (Pelangio), Trade Winds Ventures Inc. (Trade Winds), Goldcorp Canada Ltd. (Goldcorp) and Detour Gold.  Work completed included geological mapping, geochemical surveys (rock chip, grab, channel, trench and soil sampling), airborne geophysical surveys, ground geophysical surveys (Crone electromagnetic, RADEM, magnetometer, Induced polarization (IP)) , core and reverse circulation (RC) drilling, metallurgical testwork, Mineral Resource and Mineral Reserve estimates, mining studies, environmental studies, and geotechnical and hydrological studies.  Campbell mined the Campbell open pit from 1983-1987.  Placer Dome conducted underground operations from 1987-1999 and briefly restarted open pit mining in 1998.  Detour Gold commenced operations at the Detour Lake Main Pit in 2013.

Since acquisition of the Detour Gold Operations, Kirkland Lake Gold has completed additional exploration drilling, Mineral Resource and Mineral Reserve estimates, updated the mining method and mine planning, migrated data to a new Fusion database, expanded or is in the process of constructing selected infrastructure (core storage, accommodations camp, an airfield and aerodrome, onsite assay laboratory, additional mobile maintenance offices and shops) and continued with permitting of the West Detour project.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

1.7 Drilling and Sampling

Core drilling completed on the Project (including 58N) within the database totals 8,384 drill holes (1,884,240.3 m)  including 17 wedge holes. 

Drilling and assaying that supports the Mineral Resource estimate for the Detour Lake deposit was completed by Placer Dome, Tradewinds, Pelangio, and Detour Gold from 1974-2016.  Within the immediate area of the Mineral Resource estimate, there are a total of 6,519 core drill holes (1,128,965.7). 

Drilling and assaying that supports the Mineral Resource estimate for the West Detour deposit was completed from 1996-2021 by Placer Dome, Tradewinds, Pelangio, Detour Gold and Kirkland Lake Gold.  Within the immediate area of the Mineral Resource estimate, there are a total of 1,049 core drill holes (381,403.7 m).

Drilling and assaying that supports the Mineral Resource estimate for the North Pit deposit was completed from 2004-2016 by Tradewinds, Pelangio Metals, and Detour Gold.  Placer Dome completed one drill hole in the area drilled in the 1990s. Within the immediate area of the Mineral Resource estimate, there are a total of 101 core drill holes (21,945.6 m).

Drilling and assaying that supports the Mineral Resource estimate for the Zone 58N deposit was completed by Detour Gold from 2012-2017. Within the immediate area of the Mineral Resource estimate, there are a total of 370 core drill holes (138,433 m).

Core drilling from surface included the following core size diameters:  AQ (27 mm), BQ (36.4 mm) and NQ (47.6 mm).  Core drilling from underground included the following core size diameters: EX (21 mm), AQ (27 mm), BQ (36.4 mm), BQTK (45 mm) and NQ (47.6 mm).

Geological and geotechnical logging has evolved over the various exploration and mining campaigns.  Standard procedures for logging during the legacy (pre-Trade Winds) campaigns were not well documented and varied considerably between programs.  Trade Winds used the same pre-set terminology and codes as the Placer Dome programs.  Detour Gold developed a geological legend for the Project area incorporating advances in understanding of the regional and local geology, and the deposit-scale geology, structure, alteration and mineralization.  Kirkland Lake Gold generally uses the Detour Gold logging lithology legend and codes.

Surface collar surveys include a mix of measurements from cut grids, and differential global positioning system (DGPS) instruments.  The initial position and azimuth of most underground holes was typically determined using measurements from underground survey stations and reference points.

Down-hole surveys have used acid tests, and Tropari, Sperry Sun, Flexit SmartTool, Reflex EZ-Shot, Reflex Maxibor II, and Reflex Gyro Sprint-IQ instruments.  Depending on the campaign and instrumentation being used, survey data could be collected at 3-75 m intervals downhole.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

In general, core recovery exceeded 95% with losses generally occurring within overburden, the first few metres of bedrock, or when going through a fault zone.

Grade control drilling uses RC methods; these drill holes do not support Mineral Resource estimation. 

Core was typically split for sampling, with one half sent for assay and the other half retained as a reference.  A small percentage of the core drilled during Kirkland Lake Gold's ownership was not sawn and was shipped as whole core samples.  Sample intervals ranged from 0.3-1.5 m.

Bulk density determinations for the Detour Lake deposit initially used an average derived from the historical mining operations.  Kirkland Lake Gold reviewed available bulk density values, and for the current Mineral Resource estimate, a density value was determined for each assigned lithology code by constructing histograms and removing outliers and determining the average for each lithology.  The density value of 2.9 t/m³ is supported by 7,045 determinations completed by Detour Lake and Pelangio.  Lithologies without a bulk density were assigned an average density of 2.99 t/m³.  The resource estimate uses an average value of 2.90 t/m³ for the West Detour deposit, based on 2,742 determinations that were completed by Kirkland Lake Gold in 2021.  The Zone 58N estimate uses an average value of 2.8 t/m³, based on 2,644 measurements by Detour Gold.

A number of laboratories were used over the Project history.  Where known, the laboratories used during the legacy programs included Assayers Limited, in Rouyn, Quebec, (Assayers); the Dome Mine Laboratory in Timmins (Dome laboratory), Ontario; Swastika Laboratories Ltd, in Swastika, Ontario (Swastika); the Detour Lake Mine assay laboratory (Detour Lake laboratory); X-Ral Laboratories in Rouyn, Quebec (X-Ral); Bondar Clegg in Ottawa, Ontario (Bondar Clegg); Chemex Laboratories in Mississauga, Ontario (Chemex Mississauga); Chemex Laboratories in Rouyn, Quebec (Chemex Rouyn); Accurassay Laboratories in Thunder Bay, Ontario (Accurassay Thunder Bay); and Activation Laboratories Ltd in Timmins, Ontario (Actlabs).  Accreditations at the time the work was performed is not known.  All laboratories other than the Dome laboratory and the Detour Lake laboratory were independent of the operators at the time.  All laboratories were independent of Kirkland Lake Gold.  Trade Winds and Detour Gold used SGS Minerals in Garson, Ontario (SGS Garson), SGS Minerals in Don Mills, Ontario (SGS Don Mills), Accurassay in Timmins, Ontario (Accurassay Timmins), Accurassay in Thunder Bay, Ontario (Accurassay Thunder Bay), ALS Minerals in Sudbury, Ontario (ALS Sudbury), and ALS Minerals in Vancouver, B.C. (ALS Vancouver).  Where known, the laboratories held ISO17025 accreditation for selected analytical techniques.  The laboratories were independent of Trade Winds and Detour Gold and are independent of Kirkland Lake Gold.  In 2020-2021, Kirkland Lake Gold used ALS Minerals, with sample preparation completed at ALS Timmins and analysis at ALS Vancouver.  Exploration samples were also submitted to Actlabs, SGS Laboratories in Cochrane (SGS Cochrane), and AGAT Laboratories in Mississauga (AGAT).  These laboratories conducted both sample preparation and analysis.  The laboratories hold ISO17025 accreditation for selected analytical techniques.  The laboratories are independent of Kirkland Lake Gold.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Grade control samples are analysed at SGS Cochrane and Actlabs.  The laboratories currently hold ISO17025 accreditation for selected analytical techniques.  The laboratories were independent of Detour Gold and are independent of Kirkland Lake Gold.

Sample preparation and analysis protocols varied during the legacy programs.  Samples were typically crushed, ground or pulverized, and assayed using either fire assay of a one-assay-ton sub-sample, an aqua regia digestion and ketone extraction method, atomic absorption (AA) or a pulp and metallics procedure.  During the Detour Gold programs, samples were crushed, pulverized, and analyzed using either fire assaying with atomic absorption spectroscopy (AAS) finish, an inductively-coupled plasma-atomic emission spectroscopy (ICP-AES) finish, a gravimetric finish, metallic screen procedures, or an inductively-coupled plasma-optical emission spectrometry (ICP-OES) finish.  During the Kirkland Lake Gold programs, samples were crushed, pulverized, and analyzed using AAS and samples >10 g/t analyzed with a gravimetric finish. Selected high-grade samples are analyzed using a screen metallics procedure.

Grade control samples are crushed, pulverized and assayed using assay with an ICP-OES finish.  Sulphur and carbon analysis are done on 14 m composites (equivalent to one bench) using LECO.

Quality assurance and quality control (QA/QC) in the form of insertion of blanks, standard reference material (standards) and duplicates was not routinely practiced during legacy program submission of samples for analysis.  The QA/QC for the legacy programs typically relied on the laboratory's internal protocols.  After 1993, standards, blanks and duplicates were routinely inserted in the sample stream.  Review of the available QA/QC program results do not indicate any problems with the analytical programs, and the gold analytical data are acceptable to support Mineral Resource and Mineral Reserve estimation.

Kirkland Lake Gold migrated the Detour Gold Access databases to a Fusion database. Kirkland Lake Gold performed a major data verification exercise during the data migration process. Verification procedures included the review and modifications of coordinates, surveys, samples, lithologies, alteration, mineralization, deformation, structure, veining, and rock quality designation (RQD) data.  Currently, logging and geotechnical data are directly uploaded from the logging software.  Collar survey data are uploaded from a (DGPS) Topcon GR3 instrument with a Nikon total station instrument.  The Universal Transverse Mercator (UTM), 1983 North American Datum (NAD83) system was used to record position data.  Downhole survey data are uploaded from a REFLEX GYRO SPRINT-IQ™ The Universal Transverse Mercator (UTM), 1983 North American Datum (NAD83) system was used to record position data.  All data are checked using inbuilt software checking routines.

Sample security was managed by exploration staff from the drilling phase through to core processing and subsequent dispatching by contracted couriers directly to the analytical facilities.  Sample collection was systematically monitored from the drill rigs to the core facility and storage area which is turn is security monitored gated on-site preparation facility.  Chain-of-custody procedures consist of sample submittal forms to be sent to the laboratory with sample shipments to ensure that all samples are received by the laboratory.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

1.8 Data Verification

A number of data verification programs for Detour Lake and the West Detour project deposits were carried out by independent consultants and Detour Gold personnel over time. 

Kirkland Lake Gold personnel re-verified the entire database during migration of the data from the three Access databases used by Detour Gold to the current Fusion database. 

Verification programs completed by Kirkland Lake Gold include daily sample dispatch review and reporting, review and approval of drill logs prior to uploading into the Fusion database, and review and authorization of received assay data by the Senior Database Administrator and the QP prior to uploading into the Fusion database.  Other checks completed by the QP include site visits, review of geological data collection and checks that the QA/QC procedures used by Kirkland Lake Gold are consistent with standard industry practices.

A complete verification and validation of analytical, geological, and survey information was completed for the data supporting this Report from January 2020 to July 26, 2021.

Positive production reconciliation since the start of the mining operations at Detour Lake validates the assumptions of metal content and gold extraction.  The QP considers that a reasonable level of verification has been completed and that no material issues have been left unidentified from the programs undertaken.  The data are acceptable to be used in Mineral Resource and Mineral Reserve estimation.

1.9 Metallurgical Testwork

The Detour Lake Mine process plant was constructed in 2012, started operations in 2013, and has been operating since.  The plant design was based on metallurgical testwork completed during pre-feasibility and feasibility studies, conducted from 2009-2010.  Most of the metallurgical testing was completed at SGS Lakefield Research Limited in Ontario (SGS Lakefield) with follow-up testwork (lead nitrate and oxygen control) carried out on-site by site personnel.

Metallurgical testwork completed as part of the 2009 pre-feasibility study on Detour Lake included mineralogical examination; gravity recovery tests, including gravity recoverable gold (GRG) tests; cyanide leach tests on gravity tailings; grade variability testing; barren solution recycle testing; cyanide destruction tests; preparation of tailings for chemical and physical characterization and environmental testing; and environmental testwork.  During the 2010 Detour Lake feasibility study, tests focused on project optimization, and included evaluation of gold recovery versus grind size, use of oxygen in leach and crushing and grinding studies.

Since those studies, extensive plant testwork has proved the benefit of leaching with high oxygen rates and lead nitrate.  Three full grinding circuit surveys were completed by Detour Lake Operations personnel and modelled by third-party consultants BBA using JKSimMet to assist with grinding circuit optimizations and characterization.  Improvements are planned for the gravity circuit to increase gold recovery (feeding of cyclone underflow to the gravity circuit, operating the intensive leach reactor in leach mode for more time); are planned or underway for the leach circuit to increase gold recovery (addition of a sixth leach tank to the leach trains, improvements in oxygen diffusion, reduced leach densities, and lead nitrate addition); improving grind fineness (ball size optimization, process control improvement, increase ball-mill power; and expectation of reduced hardness of mineralization from Detour West); better cyanide control (limiting copper dissolution through temperature control); reducing carbon-in-pulp solution losses; and minimizing gold-in-carbon losses.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Work conducted on the Zone 58N area included head assaying, mineralogy, gravity concentration, cyanide leach tests.  The mineralization was evaluated to check if the current process plant flowsheet could be used.  Based on the results of the Zone 58N metallurgical testing, the existing Detour Lake process plant is capable of processing the Zone 58N mineralization.

Metallurgical recovery forecasts are based on equations developed during the Detour Lake pre-feasibility and feasibility studies, modified with information from ROM operations. As the West Detour deposit has similar mineralogy to that of the Detour Lake deposit, the same recovery assumptions are used for the West Detour mineralization.  The metallurgical recovery assumptions used in the 2020 Detour Lake Mine LOM plan average 91.9%.  Recoveries for Zone 58N are forecast at 98.1%.

The variability of the ore in the Detour Main Pit is related to the talc, copper and sulphur content.  The talc zone is mainly located on the southern end of the Main Pit.  Copper and sulphur are present throughout the pit in various quantities.  High-talc ores are soft and process faster.  High-talc ore used to impact recovery in the past and talc ores were limited to 15% of the plant feed.  However, the operations have that recovery can be maintained with very high lead nitrate dosage rates.  Processing of 40% talc ore in 2020 yielded similar recoveries as non-talc ore.  Sulphur content can impact recovery, and blending strategies to avoid feeding the plant with ores over 2% sulphur are in place and have worked successfully.

Copper is an element that impact cyanide and SO₂ consumption.  It is managed by blending if too high and controlling slurry temperature to leach feed.  To avoid the copper plating on the carbon, a control strategy on the cyanide/copper ratio is in place.

1.10 Mineral Resource Estimates

Mineral Resources are estimated for the Detour Lake, West Detour, North Pit and Zone 58N areas.  There are two separate geological models for the West Detour deposit. 

1.10.1 Models Supporting Mineral Reserve Estimates

The models that support the Mineral Reserve estimates have a boundary between the West Detour and Detour Lake models at section line 16,995 E.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The geological model for Detour Lake consists of 3D wireframes built by Kirkland Lake Gold in 2020.  The geological model for the West Detour deposit consists of 3D wireframes built in 2013 by Detour Gold and Thon Consulting. The geological model for the North Pit is based on interpreted mineralized zone (domain) established using an Indicator Kriging (IK) interpolation of gold grades using at an indicator cut-off grade of 0.2 g/t Au and a 0.4 cut-off probability to be above the grade cut-off built by P. Daigle Consulting Services in 2016. The geological model for 58N consists of 3D wireframes built in 2018 by G Mining Services Inc. 

Drill hole spacing across the Detour Lake deposit is generally on the order of 40 m in the north-south and east-west directions.  A block size of 10 x 10 x 7.5 m was selected to accommodate the drill hole spacing and width of the mineralization.  Drill hole spacing across the West Detour deposit is generally on the order of 40 m in the north-south and east-west directions.  A block size of 10 x 5 x 6 m was selected to accommodate the drill hole spacing and width of the mineralization.  The West Detour deposit has narrower mineralized zones and the model was built at 6 m heights, offering the possibility of regularizing (combining) two blocks into a 12-m bench, or selecting 6-m benches.  Mineral Resource reporting is done on the combined 12-m block size. A block size of 6 x 3 x 6 m was selected to model the North Pit deposit in order to capture the width of mineralization and planned higher mine selectivity. The Zone 58N model was created to encompass all the known mineralization drilled at Zone 58N, and block sizes were decided based on a typical underground mining scenario (3 m minimum width).  Due to the often narrow nature of mineralization, a percentage block model was adopted in Geovia GEMS, and subsequently converted to a sub-blocked model for mine planning purposes.

Three main broad mineralized domains (MZ1, spatially associated with the chert marker horizon; MZ2, associated with the historic Quartz Hangingwall mineralized zone; and MZ3, encompasses widespread disseminated mineralization to the north of MZ2) were defined, with a fourth zone (MX4) containing all data that were not part of the three mineralized domains.  Nine domains were constructed for West Detour, by interpreting limits of mineralization on sections that corresponded to broad mineralized zones with higher than usual concentration of samples with potentially economic gold grades.  Domain 1 at West Detour corresponds to the chert marker horizon geological unit.  All the other mineralized domains were built around Domain 1.  Three geological domains were created for the North Pit, together with a gold grade envelope that used a cut-off grade of 0.20 g/t Au.  Nine domains were modelled for Zone 58N, based on alteration intensities described as moderate or stronger, plus an additional zone of mineralization present in the hanging wall.

A 3D model of all prior mined areas in the Detour Lake area was created from available plans and sections.  Individual models were created for underground access, stopes, and the Campbell open pit.  Volume reconciliation versus prior mining records showed that the majority of underground openings are accounted for.  This model was used to deplete the block model. 

For Detour Lake, samples for grade estimation were first composited to 1 m, separated by mineral zones, capped, and then composited into 5 m down-hole intervals.  Composites for the West Detour deposit were created on 5 m capped grade down-hole intervals.  The North Pit dataset was composited on 3 m down-hole intervals. A composite length of 2 m was selected for Zone 58N, which resulted in a minimum of two composites per drill hole (applying a 4 m minimum downhole thickness rule) per domain.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Grade capping was applied based on a reconciliation study for Detour Lake, and on examination of probability plots for West Detour, North Pit and Zone 58N.

Spatial continuity of the composite grades within each deposit was assessed using variography and correlograms.

At Detour Lake, average length weighted densities were determined for these different lithologies.  The average density for each lithology was then assigned to the global drillhole database.  Intervals without a density value were assigned a value based on a similar lithology and indeterminate intervals were assigned an average density of 2.99 t/m³.  A density of 2.9 t/m³ in rock and 1.8 t/m³ in overburden and backfill was used for tonnage determination in the West Detour and North Pit models. The Zone 58N deposit used a density of 2.7 t/m³, derived from drill core measurements.

The interpolation of the Detour Lake resource model was completed using ordinary kriging (OK).  An inverse distance weighting to the second power (ID2) interpolation, an ID3, and nearest neighbour (NN) estimates were completed concurrent to the OK estimate for validation purposes.  Density was estimated using an ID3 method and used the gold search parameters.  The interpolation of the West Detour deposit resource model was completed using OK.  The North Pit deposit block model was estimated using OK interpolation method on 3 m capped composite gold grades.  ID2 and NN interpolations were also estimated for validation purposes.  Due to the highly erratic distribution of gold grades at Zone 58N, a five-pass interpolation strategy was adopted using a combination of NN and ID3.

Models were validated using a combination of visual inspection, global bias checks and swath plots.  Results were considered acceptable.

Mineral Resource confidence classifications were assigned based on a combination of distance to the nearest drill hole, a minimum number of drill holes, and geological and grade continuity.

1.10.2 Models Supporting Mineral Resource Estimates

The descriptions provided in Section 1.10.1 for the estimates for the Detour Lake, North Pit and Zone 58N remain the same for the resource model estimates.  The West Detour estimate has updated model limits.  The models that support the Mineral Resource estimates have a boundary between the West Detour and Detour Lake models at easting 590140.

The updated model is only used for Mineral Resource reporting, and does not support the Mineral Reserves.

The West Detour area was domained into 10 zones, based primarily on visual observation of gold grade, however, zones may coincide with geological features that can be identified over longer strike lengths.  A block size of 10 x 10 x 7.25 m was selected as an appropriate simulated mining unit.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Samples were initially composited to 1 m lengths for capping purposes, then re-composited to 5 m lengths.  Gold grade caps varied by domain, ranging from 7-70 g/t Au.  Variography was completed by modeled domain using the capped 5 m composites.  Variograms have a significant nugget with an average of 29%.

The estimation of gold grades for West Detour were completed using OK.  All but one domain had hard boundaries for estimation purposes.  Gold was estimated in six passes of expanding volumes.  The first two passes used a minimum of seven composites and a maximum of 16 composites to estimate a block, and the third to sixth passes included a minimum of four composites and maximum of 16.  In the multiple pass process, once a block was estimated, it was not re-estimated in subsequent passes.

Estimation validation included visual inspection, examination of swath plots, and comparison of the OK estimate with NN and ID2 estimates.  Results were considered acceptable.

Mineral Resource confidence classifications were assigned based on a combination of distance to the nearest drill hole, a minimum number of drill holes, and geological and grade continuity.  No Measured Mineral Resources were classified.

1.10.3 Reasonable Prospects of Eventual Economic Extraction

The Detour Lake, West Detour and North Pit resource models were combined in a common model.  A pit optimization exercise using Maptek Vulcan software was conducted based on the parameters listed in Table 1-1, which were based on mid-year 2021 cost estimates.  The exercise constrained the Measured, Indicated and Inferred Mineral Resource estimates.  A revenue factor of one was used to guide the pit design.  The conceptual pit encompassed both Detour Lake and West Detour within a single pit.  The North Pit remained as a separate pit.  For resource estimation reporting purposes, the common model was divided along section line 16,995 E to separate the Detour Lake estimate from the West Detour estimate. The combined model was adjusted for mining depletions as of end July, 2021.  Mineral Resources are reported at variable cut-off grades, ranging from 0.35-0.5 g/t Au.

The Zone 58N deposit estimate assumes that the deposit will be mined using underground mining methods, based on the use of transverse and longitudinal long-hole stopes.  The stoping geometry and stope heights are based on geological interpretation with dilution assumptions considered.  The mineralized domains were modelled with a minimum thickness of 4 m downhole (approximately 3 m true thickness), to ensure that minimum underground mining widths were addressed.  The estimate is reported above a cut-off grade of 2.2 g/t Au using the parameters listed in Table 1-2.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table 1-1: Conceptual Resource Pit Optimization Parameters

Table 1-2: Underground Cut-off Grade Input Parameters

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

1.11 Mineral Resource Statement

Mineral Resources are reported using the 2014 CIM Definition Standards and are reported exclusive of those Mineral Resources converted to Mineral Reserves.  Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.

Mineral Resources are reported in Table 1-3 and Table 1-4.  The Mineral Resources estimated for the North Pit and Zone 58N have an effective date of December 31, 2020. The Mineral Resources estimated for Detour Lake and West Detour have an effective date of 26 July, 2021.  The Qualified Person for the Detour Lake, North Pit, and Zone 58 N estimates is Mr. Andre Leite, P.Eng., a Kirkland Lake Gold employee.  The Qualified Person for the West Detour estimate is Mr. Juan Figueroa, P.Geo., a Kirkland Lake Gold employee.

Factors that may affect the Mineral Resource estimates include:  metal price and exchange rate assumptions; changes to the assumptions used to generate the estimation domains; changes in local interpretations of mineralization geometry and continuity of mineralized zones; changes to geological and mineralization shape and geological and grade continuity assumptions; changes in the treatment of high-grade gold values; density assignments; changes to geotechnical, mining and metallurgical recovery assumptions; changes to the input and design parameter assumptions that pertain to the assumptions for open pit and underground mining constraining the estimates; and assumptions as to the continued ability to access the site, retain mineral and surface rights titles, maintain environment and other regulatory permits, and maintain the social license to operate.

There is no material difference between the two West Detour resource models within the designed pit shapes that constrain the Mineral Reserve estimates.

The additional mineralization in the updated West Detour model represents potential Project upside.  There is potential to redesign the Detour Lake and Detour West open pits to convert some or all of those Indicated Mineral Resources to Mineral Reserves, and thus revise the mine plan and potentially increase the mine life.  However, mining studies such as assessment of tailings and waste rock storage capacities, optimized pit planning and consideration of any future permitting requirements will have to be considered in such a conversion.

1.12 Mineral Reserve Estimates

Mineral Reserves are reported as the diluted ore tonnage and grade scheduled to be fed to the mill over the life of the operation, based on open pit mining methods.  The associated production schedule considers an optimized mill and stockpile strategy to maximize discounted cash flows.  Measured and Indicated Mineral Resources within the Detour Lake, West Detour and North Pit final pits as discussed in Section 1.10.1 were converted to Proven and Probable Mineral Reserves respectively.  There is no material difference between the two West Detour resource models within the designed pit shapes that constrain the Mineral Reserve estimates.  Inferred Mineral Resources captured within the pit shells were set to waste.

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Table 1-3: Measured and Indicated Mineral Resource Statement

Table 1-4: Inferred Mineral Resource Statement

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Notes to accompany Mineral Resource tables:

1. The Mineral Resources estimated for the North Pit and Zone 58N have an effective date of December 31, 2020. The Mineral Resources estimated for Detour Lake and West Detour have an effective date of 26 July, 2021.  The Qualified Person for the Detour Lake, North Pit, and Zone 58 N estimates is Mr. Andre Leite, P.Eng., a Kirkland Lake Gold employee.  The Qualified Person for the West Detour estimate is Mr. Juan Figueroa, P.Geo., a Kirkland Lake Gold employee.

2. Mineral Resources are reported exclusive of those Mineral Resources converted to Mineral Reserves.  Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.  Mineral Resources are reported using the 2014 CIM Definition Standards.

3. Mineral Resources considered amenable to open pit mining methods were estimated using a gold price of US1,500/oz, variable metallurgical recovery assumptions based on formulae, refining and transport costs of C$5/oz Au, 2% royalty, mining costs of C$3.05/t mined, process costs of C$8.82/t milled, general and administrative costs of C$3.47/t milled, non-mining sustaining capital costs of $2.19/t milled, mining sustaining capital costs of C$0.56/t mined, incremental bench cost of $0.019/t/bench, and variable pit slope angles that range from 25-58º.  The estimate is reported above cut-off grades that vary from 0.35-0.5 g/t Au.

4. Mineral Resources considered amenable to underground pit mining methods were estimated assuming long-hole and transverse stoping methods.  The estimates used a gold price of US1,300/oz, metallurgical recovery assumption of 97%, refining and transport costs of C$5/oz Au, average mining cost of C$75/t mined, process and tailings costs of C$9/t milled, general and administrative costs of C$11.50/t, assumed dilution average of 12%.  The estimate is reported above a cut-off grade of 2.2 g/t Au.

5. Estimates have been rounded in accordance with reporting guidelines.  Totals may not sum due to rounding.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Each deposit was optimized independently to reflect the different bench height planned for that pit.  The parameters and respective values assumed in the pit optimization process are presented in Table 1-5.  Based on the costs and price assumptions presented in the table, a set of pit shells associated with a range of revenue factors was generated for each of the deposits.  The final pit selection was based on conventional best-worst case analysis of discounted cash-flows.  The selected shells guiding final pit design were associated with revenue-factors of 0.88 for Detour, 0.95 for West Detour and 0.90 for North Pit. 

The engineered pit designs were completed using the pit optimization shells as a guide in order to maximize the value and gold recovered inside the ultimate pits.  The resulting pit designs include practical geometry that is required in an operational mine, such as the haul road to access all the benches, recommended pit slopes with geotechnical berms, proper benching configuration and smoothed pit walls.

The cut-off evaluation incorporated considerations of mill and stockpile capacities, mine constraints and economic parameters when defining mill and stockpile cut-off grades over time in a yearly basis.  The marginal cut-off grade is 0.27 g/t Au but an elevated cut-off of 0.35 g/t Au is used as a minimum in the cut-off grade optimization process.  Mining will use the variable optimized cut-off grade strategy, because it moves forward ounce production and delays stripping as much as possible.

Mine dilution is accounted for by the use of mine panels that emulate variable degrees of dilution as a function of the continuity of the mineralization at different cut-off grades.  Different panels sizes and dimensions were tested against production reconciliation results for the past four years (2016-2019) at a cut-off grade of 0.5 g/t Au.  The average dilution factored in over the LOM represents a 7% increase in tonnage and 6% lower grade. 

1.13 Mineral Reserve Statement

Mineral Reserves are reported using the 2014 CIM Definition Standards.  The Qualified Person for the estimate is Mr. Andre Leite, P.Eng., a Kirkland Lake Gold employee.  Mineral Reserves have an effective date of December 31, 2020 and are summarized in Table 1-6.  Mineral Reserves are reported using a variable optimized cut-off strategy with a minimum cut-off grade of 0.35 g/t Au.

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Table 1-5: Pit Optimization Parameters

Note: = * includes First Nations agreements associated costs

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Table 1-6: Mineral Reserves Statement

Notes to accompany Mineral Reserves table:

1. The Mineral Reserves have an effective date of December 31^st 2020. The Qualified Person for the estimate is Mr. Andre Leite.

2. Mineral Reserves amenable to open pit mining methods were estimated using a gold price assumption of US$1,300/oz, an exchange rate of 1.31 C$/US$, a 2% net smelter return royalty, refining charge of 0.05%, variable metallurgical recoveries based on a formula, inter-ramp pit slope angles that range from 25.1-56.3º, mining cost of C$3.42/t mined, incremental haulage costs of C$0.019/7.25 m bench at Detour Lake and C$0.15/5 m bench at West Detour and North Pit, process costs of C$9.75/t milled, general and administrative costs of C$3.59/t milled, non-mining sustaining capital costs of C$3.42/t milled, and mining sustaining capital costs of C$0.35/t mined.  The estimate is reported above variable optimized cut-off and a minimum cut-off grade of 0.35 g/t Au.

3. Estimates were rounded in accordance with reporting guidelines.  Totals may not sum due to rounding.

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Factors that may affect the Mineral Reserve estimates include: changes to the gold price and exchange rate assumptions; changes to pit slope and geotechnical assumptions; changes to operating cost assumptions used in the constraining pit shell; changes to pit designs from those currently envisaged; unforeseen dilution; changes to hydrogeological and pit dewatering assumptions; changes to inputs to capital and operating cost estimates; ability to permit West Detour and North Pit pits and western extent of the ultimate Detour Lake pit; and changes to modifying factor assumptions, including environmental, permitting and social licence to operate.

1.14 Mining Methods

The geotechnical design parameters for Detour Lake Main Pit were reviewed by Golder in 2020.  The assessment accounts for a revised bench height of 14.5 m for the Main Pit implemented in 2020 and for information obtained as temporary and final walls are exposed.  The geotechnical parameters for the West Detour and North pit were also provided by Golder.  A process of ongoing geotechnical monitoring and documentation was implemented at the mine and additional risk mitigation techniques continue to be evaluated and employed as needed.

The mine water management plan is matched to the mine development strategy.  Water management infrastructure includes non-contact water diversion structures and water retention ponds, appropriately sized based on hydrological/hydrogeological modeling and the changes in mining activity and stockpiling over the LOM.

The Detour Lake pit design incorporates a double ramp access for most of the LOM.  The final ramp and principal access will be located in the north wall.  The West Detour and North Pit were designed using a single ramp access.  There are a total of nine phases designed for the LOM: five for the Detour Lake Main Pit, three for the West Detour Pit and one for North Pit. 

The mine operation also requires the management of old underground workings; in general, historical records of underground workings are very reliable.  Standard operational procedures regulate the mining activity in these affected areas to ensure a safe operation and risk management.

Both waste rock storage facility (WRSF) and stockpile strategies are in agreement with the permitting strategy for the West Detour pit; and respect related environmental constraints.  Currently the mine has two WRSFs (MRS1 and MRS2), one ore stockpile (ROMPAD) and one overburden/topsoil stockpile for mine reclamation purposes (OVB1). The mine plan accounts for three additional ore stockpiles (MRS4, MRS5 and a temporary stockpile within the MRS2 WRSF footprint), three new WRSFs (MRS3, MRS2-extension and Inpit) and one new overburden/topsoil stockpile (West Detour Overburden stock).

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The Detour Lake Mine uses conventional truck-shovel open pit mining.  The mine is operated using an Owner-operator mining equipment and labour strategy.  Excluding the muskeg and overburden/till top layer, all material must be blasted.  Pioneering drilling and blasting is required in the overburden/rock contact.  Additionally, during winter months free digging of overburden material is not possible due to frost. 

Mining at West Detour is planned to employ similar conventional mining methods with the initial use of smaller equipment for the pre-stripping phase, especially in overburden.  Given the smaller dimensions of the North Pit, a smaller fleet size will be used. 

The Detour Lake Mine operates 24-hr per day year-round on 12 hr shifts for all operational crews. Operational teams work on a 7-day in/7-day out rotation. The mine has implemented a successful hot-seating process for its main production equipment (shovel, trucks and drills).  Management/supervisory and support personnel work at site on different schedules.

The mine production schedule forecasts a total 1,725 Mt to be mined over a period of 18 years (2021-2038).  A total of 597 Mt of ore is planned to be milled over a period of 22 years (2021-2042); with the last four years of production supported by long-term stockpile reclaim.

The optimized and variable cut-off strategy combined with 158 Mt of stockpile capacity, results in an average LOM stripping ratio of 1.90. 

1.15 Recovery Methods

The process plant is based on a robust metallurgical flowsheet designed for optimum recovery with minimum operating costs.  The flowsheet is based upon unit operations that are well proven in industry.

The primary crushing system is a single stage, open circuit, primary gyratory crusher that feeds a secondary cone crusher operated in open circuit.  The gold recovery circuit selected was a leach circuit followed by a carbon-in-pulp (CIP) circuit.  The mineralization then proceeds to acid wash, stripping, electrowinning, and refining. 

The processing plant was designed to process ore at an average throughput of 55,000 t/d or 20 Mt/a, equivalent to milling rates of 2,500 tonnes per operating hour (tpoh) with operating time of 92% in a 24 hour day.  While operating time has lagged at around 89%, the milling has far exceeded the design rate averaging 2,952 t/hr in 2020 for 23.06 Mt milled.  On at least 70 occasions in 2020, a 74 kt milled per day rate was achieved. 

With the upturn of current performance of the processing plant, ongoing optimization efforts and some new capital initiatives, the LOM plan assumes that the plant throughput will increase from 23 Mt in 2020 to 28.0 Mt in 2025 and thereafter.  The annual plant throughput of 28.0 Mt is planned to be achieved by increasing the milling rate to 3,436 t/hr and improving operating time to 93%.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Various initiatives have been developed to bring the plant to the 28 Mt throughput rate.  Those initiatives are: improved fragmentation; improved primary crusher choke feeding; secondary crusher screens; curved pulp lifters; semi-autogenous grind (SAG) mill speed increase; permit to go over 75,000 t/d; re-feed system after the secondary crushers; pebble crusher variable speed drives; ore blending; and an increase in plant operating time to 93%.

Energy consumption is not expected to significantly increase as a result of the increased throughput rate.  A lot of the initiatives to increase plant throughput are related to increases in grinding efficiency with the same power.  The LOM assumes at 28.0 Mt to use 731,000 MWh per year, which the plant electrical system is adequately designed to supply.

A decant tower system is used to reclaim and pump water from the tailings management area (TMA) back to the process plant to satisfy process water requirements.  For Cell#2 a barge reclaim water system will be used.  Reclaim water is piped to the process plant.  Depending on the water balance in the TMA, water from the open pit and various collection ditches around the WRSFs can also be directed to the plant.  Make-up water for the reagent mixing is sourced from East Lake when required.

Consumables used in the plant include: steel balls; quicklime (CaO); sodium cyanide (NaCN) for gold dissolution and desorption; SO₂ and SMBS; anti-scalant; caustic; copper sulphate; carbon is used for gold collection; and ore anti-freeze conditioner.

1.16 Project Infrastructure

Surface infrastructure to support operations is primarily in place, and includes:

• Three open pits:  Detour Lake Main (in operation), West Detour and North Pit (to be constructed);

• Processing facilities:  grinding and leaching facilities, along with management and engineering offices, change house, workshop, warehouse, and assay laboratory facilities;

• Mine facilities:  management and engineering offices, change house, heavy mining vehicle and light vehicle workshops, wash bay, warehouse, explosives magazine, crusher, mine access gate house, return water pump house;

• Administration buildings:  facilities for overall site management, safety inductions, and general and administrative functions;

• Accommodation camp;

• Four stockpiles: ROM pad, MRS4, MRS5 and the temporary MRS2;

• Four WRSFs: MRS1, MRS2, MRS3 and Inpit ;

• Three tailings storage facilities: cell 1, 2 and 3;

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• Water management facilities:  stormwater and water storage dams, diversions, culverts;

• Landfill facility.

Projects were ongoing through 2020 which included construction of additional camp capacity, construction of an airfield and aerodrome, construction of an onsite assay laboratory, construction of additional mobile maintenance offices and shops, and construction of additional exploration facilities.

Facilities in Cochrane include administration offices, a bus terminal with employee parking lot and security check-ins, four houses and an eight-unit apartment block. Kirkland Lake Gold has a shared services centre in Timmins that services the Detour Lake Mine.  SGS Minerals operates a full-service analytical laboratory in Cochrane in support of the Detour Lake Mine.

Workers are accommodated in two camps.  The Little Hopper Lodge (previously referred to as the Permanent Camp) is located 7 km west of the mining operations in close proximity to Little Hopper Lake.  The Sagimeo Lodge is located just south of the mine services building.  Accommodations are in the process of being expanded, and will have a total capacity of 1,447 persons.

Potable water for the Little Hopper Lodge is obtained from Little Hopper Lake.  This is adequate for the Detour Lake's current and future needs.  Potable water for the Sagimeo Lodge, mine services facilities, site administration facility, and the processing plant is obtained from borehole wells close to the camp.  Fresh water is pumped from East Lake and is primarily used in the processing plant for reagent mixing but is also used as wash water in the truck wash facility and water make-up for the fire water tank.

The existing 180 km-long powerline runs from the processing facility to a tie in at Island Falls, and thence to the Pinard substation.  The 230 kV transmission line allows for the distribution of more than 85 MW of power, suitable to service the entire Detour Lake Operations.  In the event of a power failure, there is sufficient emergency power generation for the provision of basic services.

1.17 Environmental, Permitting and Social Considerations

1.17.1 Environmental and Supporting Studies

The Detour Lake Main Pit and West Detour areas were subject to extensive baseline, environmental monitoring, and technical studies, as per provincial and federal regulatory requirements.  The presence of Woodland Caribou is of particular note because it is a Species at Risk, designated as Threatened under the Provincial Endangered Species Act (ESA) and Federal Species at Risk Act. Potential impacts and mitigation measures are being addressed through the Endangered Species Act Overall Benefit Permit, for which approval is anticipated in late 2021.

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1.17.2 Monitoring

The mine is required to comply with air quality standards, point of impingement guidelines, and ambient air quality criteria specified in Ontario Reg. 419/05.  The installed operating monitoring systems demonstrate compliance with these standards, which confirms the predictions of no significant air quality or noise impacts.

Due to historical mining in the region, the geological materials (ore, waste rock, tailings, and overburden) at the Detour Lake Main Pit have undergone multiple metal leaching and acid rock drainage (ML/ARD) assessments by various investigators in compliance with best-practice, industry-standard methods.  To date, over 80% of waste rock has been classified as non-potentially acid generating (NAG). Analytical results continue to support that ARD risk is low based on low sulphide content.  To provide greater assurance in the event of ARD during operations and/or closure, PAG and NAG waste rock materials are segregated into separate stockpiles.  Production tailings are governed by the same classification criteria as waste rock and are subject to frequent confirmatory sampling.

Mine-contact water from all mine facilities, including stockpiles and tailings management area (TMA) cells, is captured by the water management system, a network of collection ditches, ponds, pipelines and pumping infrastructure to ensure environmental protection.  Discharge of surplus mine-contact water occurs only at select, specially permitted locations, provided that water quality meets federal, provincial, and site-specific permitted criteria. Water that has been in contact with processing reagents (i.e., water stored in the TMA) is not discharged, and is instead re-circulated through the process plant or locked in tailings void spaces. 

Kirkland Lake Gold notes the following:

• Water quality:  the monitoring network includes approximately 71 surface water stations and 141 groundwater stations.  Regular data collection, analysis, and interpretation on a monthly and quarterly basis allow for risk identification and adaptive management;

• Fisheries and other aquatic resources:  mitigation measures were implemented to limit potential effects related to mining of the Detour Lake Main Pit on aquatic resources.  In addition, a fish compensation plan was approved by the federal and provincial regulatory agencies, following full consultation with Indigenous communities, to address impacts related to the development of the TMA and mine rock stockpiles.  Additional mitigation measures and compensations plans have been proposed to address potential impacts to fisheries and other aquatic resources related to the development of the West Detour pit.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

• Groundwater:  no significant environmental impacts to groundwater are currently predicted to occur in conjunction with the mining of the Detour Lake Main Pit, West Detour Pit, or North Pit, or the development of mine rock stockpiles or the TMA, after the implementation of proposed mitigation measures;

• Vegetation and wildlife:  measures to minimize adverse effects to area plants and wildlife include but are not limited to:  optimizing the Project footprint; maintaining a minimum 120 m buffer around watercourses; avoidance of unnecessary disturbance to wetlands; and avoidance of tree clearing during the bird nesting period.  Recommendations for the protection of Woodland Caribou include as reasonable:  minimizing the overall project footprint; avoidance of critical over-wintering habitat; minimizing disturbance to mature upland black spruce-jack pine forests that support a high abundance of terrestrial and arboreal lichens (a preferred food source); and minimizing the potential for caribou/vehicular traffic interaction.  Kirkland Lake Gold has also implemented a caribou tracking and monitoring program.

• Cultural and heritage resources:  none of the studies completed identified archaeological sites that are proximal to the Detour Lake Mine site, including the West Detour area, that are likely to be affected by the mine in any foreseeable manner.  The overall potential for encountering unforeseen cultural heritage or archaeological sites that would conflict with the proposed development plan for the site is considered to be extremely low.

1.17.3 Tailings Management Area

Tailings are stored at surface in an engineered TMA located east of the process plant.  The TMA consists of three cells being developed in a planned, progressive manner: Cell 1 was built over a historic tailings storage facility from a previous mining operation; Cell 2 was developed to the north of Cell 1; and the Cell 3 area was cleared to the south of Cell 1.  Cells 1 and 2 are dominantly tailings storage cells, while the Cell 3 area will first be used for the mine water pond (a water management facility), until the Cell 3 tailing facility is constructed later in the mine life (2027).  The TMA is designed to function as three independent cells for tailings and water management.  Tailings deposition will generally occur in only one cell at any time with water recycle for process plant use occurring mainly from the active cells, but possibly also during some periods from the inactive deposition cell prior to final closure.

The initial design of the TMA was optimized during ongoing operations, as additional information became available through ongoing construction and in response to a requirement for additional capacity (and wish to stay within the same footprint).  In Q4 2020, tailings deposition was transitioned from Cell 1 to Cell 2. The construction of a thickened tails tails is planned with deposition of thickened tails starting in January 2025. Starting in 2037, tails are to be deposited in the Detour Main Pit (mine operation in the Detour Main Pit is forecast to be complete in 2036).  The TMA Cell 2 and Cell 3 facility will provide for storage of approximately 283 Mm³ (454 Mt) of tailings solids.  Capital investment is reflected in the cash flow model.

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Inspection and monitoring is performed during construction and operation of the tailings dams to assess their performance and safety; and to verify that actual conditions are consistent with the design assumptions and intentions.  Inspection and monitoring also optimizes maintenance and repair costs, provides warning of potential impending risks, and provides sufficient time to implement remedial measures, if required.  A dam safety review completed in 2020 confirmed that the TMA is performing as designed.

1.17.4 Water Management

Environmental protection is ensured through the water management network, which collects seepage and runoff from all mine waste facilities through a system of ditching, pumping, and pipeline infrastructure. The modular design allows for the addition of treatment facilities if required. In 2020, a mine water pond with a capacity of 3.5 Mm³ was completed. The mine water pond serves as a central water management facility (e.g., for open pit water and local runoff), and provides additional contingencies for storage and treatment, if needed.

Tailings, tailings slurry water, and water reclaimed for the operation of the process plant are managed through the TMA.

1.17.5 Permits

Most mining projects in Canada are reviewed under one or more Environmental Assessment (EA) processes.  The federal EA process for Canadian mines is detailed in the CEAA.  A federal EA was triggered for the Detour Lake project due to:

• The requirement for an Explosives Factory License under the Explosives Act for a project-dedicated explosives manufacturing factory; and

• The need for one or more Authorization(s) for Harmful Alteration Disruption or Destruction of Fish Habitat according to the Fisheries Act.

These licences/authorizations were granted.

Four provincial EAs were approved for the Detour Lake project:

• July 2010:  Ontario Ministry of Environment Class EA for Electricity Projects, for the diesel power generation required to support the construction phase (AMEC 2010a);

• November 2010:  Ontario MNR Class EA for Resource Stewardship and Facility Development Projects, for the construction of facilities off-lease, and for such aspects as on-lease aggregate operations or in-water works (AMEC 2010c);

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• December 2010:  Ontario individual EA for Electricity Projects, for construction of a 230 kV transmission line (AMEC 2010b);

• March 2012:  Ontario MOE individual EA for Electricity Projects of 10 MW, for allowing a diesel-generated contingency power supply to service the construction needs should the powerline not be operable by the third quarter of 2011.  With the successful energizing of the powerline in October 2011, these facilities were not installed.

In accordance with Section 143(2) of the Mining Act, R.S.O. 1990, Detour Gold submitted a Mine Closure Plan (for Production) in 2010, followed by Closure Plan Update Amendments in 2014 and 2019. ENDM filed these documents on October 28, 2010, February 18, 2015, and November 8, 2019, respectively.  In addition, a scoped closure plan amendment was submitted in early 2021 and filed during August 2021 specifically for the airstrip.

Subsequent permits, such as Permits to Take Water and Environmental Compliance Approvals, have been approved, renewed, and/or amended as needed in order to support ongoing development and operations.

Prior to development of the West Detour project, a number of Provincial and Federal environmental approvals, or amendments to existing approvals, will be required. In particular, the West Detour project is subject to a Class C Environmental Assessment pursuant to the Ontario Environmental Assessment Act as managed by NDMNRF.  The Environmental Study Report (ESR) was published in draft in January 2017, and a final ESR was submitted to NDMNRF in August 2019.  An ESR addendum was submitted in October 2020 to address additional comments from government and Indigenous communities.  The West Detour ESR was approved and a statement of completion was provided in March 2021.

The environmental approval applications will provide additional detail regarding the engineering design of the proposed West Detour project facilities, potential effects and proposed mitigations measures.  No changes were expected to the approvals list at the Report effective date.

1.17.6 Closure and Reclamation

Kirkland Lake Gold acknowledges that the company will be responsible for providing the full amount of the financial assurance for the closure and rehabilitation of the Detour Lake Mine and the West Detour project, subject to any required or approved changes to the Closure Plan.  There are six developmental phases that trigger the issuance of security bonding for the operation.  Financial assurance is submitted to theNDMNRF prior to the beginning of the associated activities of each phase, or as otherwise arranged with the NDMNRF. 

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As per the Detour Lake Mine Closure Plan Amendment 2, the total estimated closure cost for the Detour Lake Operations at peak development (i.e., all facilities constructed) is $149,811,737, exclusive of the West Detour project.  Security provided to the NDMNRF to date for the present stage of development totals $105,798,258.  Financial assurance for the West Detour project will be formalized with the filing of Closure Plan Amendment 3, anticipated for Q2 2022/Q3 2022.

1.17.7 Social Considerations

Kirkland Lake Gold has undertaken ongoing consultation with the public, government regulators and its Indigenous partners regarding the operations, environmental commitments and planned activities.  Kirkland Lake Gold has established the following consultation principles:

• Early notification;

• Open communication; 

• Accessible information;

• Flexible process;

• Capacity building;

• Mutual respect.

These principles continue to guide interactions within mine permitting, operations, and exploration.

Kirkland Lake Gold has agreements with First Nations who have treaty and Indigenous rights which they assert within the operations area of the Detour Lake mine. These agreements provides a framework for strengthened collaboration in the development and operations of the mine and outlines tangible benefits for the First Nations, including direct financial support, skills training and employment, opportunities for business development and contracting, and a framework for issues resolution, regulatory permitting and Kirkland Lake Gold's future financial contributions. In addition, Kirkland Lake Gold engages with Indigenous communities in connection with permitting applications and ongoing projects.

1.18 Markets and Contracts

No market studies are currently relevant as Detour Lake is an operating mine producing a readily-saleable commodity in the form of doré.  Doré is sent via secure transportation to a refinery for further refining.  Detour Gold sells its gold production into the market at spot prices or on a forward sales basis.  The proceeds from these sales are credited to Detour Gold's account upon delivery of the gold to the counterparty.  The estimated bullion transport costs, liability charges and refining costs used for the financial analysis are based on contract prices agreed with third-parties.

Commodity prices used in Mineral Resource and Mineral Reserve estimates are set by Kirkland Lake Gold at the corporate level.  The current gold price provided for Mineral Reserve estimation is US$1,300/oz, and US$ 1,500/oz for Mineral Resource estimation.  Both Mineral Resource and Mineral Reserve estimates use an exchange rate assumption of 1.31 C$/US$.

Kirkland Lake Gold has a number of contracts, agreement and/or purchase orders in place for supply and services that are material to the operation.  All contracts or agreements are negotiated with vendors and have a contractual scope, terms and conditions.  Contracts are negotiated and renewed as needed.  Contract terms are considered to be within industry norms, and typical of similar contracts in Canada with which Kirkland Lake Gold is familiar.

1.19 Capital Cost Estimates

Capital costs consist largely of mining equipment (replacements, additions, component replacements, capitalized maintenance), construction of tailings cells and dam raises, deferred stripping using a by-phase approach, and processing plant projects to increase plant capacity to 28 Mt/a.

Capital costs for the first three years of plan are based on budget cycle estimates with supplier quotes, engineered designs, maintenance strategies, production plans or preliminary estimates.  Estimates in later years are based on maintenance strategies, equipment replacement schedules, and long-term sustaining capital estimates are based on recent operating history and current asset value.  Tailings cells 2 and 3 are based on physical material movement requirements and recent unit cost history.

The LOM capital cost estimate is provided in Table 1-7.  The LOM plan estimated total capital cost is C$4,744 million. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

1.20 Operating Cost Estimates

Operating costs for are based on actual costs seen during operations at site and are projected through the LOM plan.

All operating costs were evaluated on an annual basis and include all costs related to:

• Mining ore and waste from the Detour Lake, West Detour and North pits;

• Processing of ore;

• All expenses associated with site administration;

• Adjustments for deferred stripping and changes in inventory; 

• Costs related to agreements with First Nations;

• Royalties to Franco Nevada and First Nations.

The consumables for the operation are based on current prices or contracts for future years.  In general, approximately 80% of operating costs are based in Canadian dollars and 20% have US dollar exposure.  The exchange rate used in the financial model is 1.31 C$/US$.

The LOM operating cost estimate is provided in Table 1-8 and Table 1-9.

The LOM plan estimated total operating cost is $12,538 million.  The LOM mining unit cost¹  is C$3.47/t mined.  The LOM operating unit cost in C$/t milled¹ is C$21.00/t milled.  The LOM operating unit cost in C$/oz sold¹ is C$864/oz sold.

1.21 Economic Analysis

The Project was valued using a discounted cash flow approach.  Estimates were prepared for all the individual elements of cash revenue and cash expenditures for ongoing operations.  Cash flows are assumed to occur in the middle of each period. 

Operating costs were prepared based on recent operating history and technical assumptions associated with the production profile.  Capital costs were prepared based on engineering estimates, vendor quotes, maintenance strategies, or estimated long-term requirements based on current asset value.

The currency used to calculate the cash flow is Canadian dollars.  A discount rate of 5% was assumed based on more than seven years of commercial production in a stable low-risk jurisdiction.

________________________________
¹Refer to Cautionary Statement on Non-IFRS Financial Performance Measures. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table 1-7: Capital Cost Summary by Area

Notes:  1.  Includes capital projects, equipment replacements/additions, planned component replacements, and capitalized portion of maintenance and repair contract of 795 haul trucks.  2. Includes infrastructure, water management, and camp.

Table 1-8: Operating Cost Summary

Notes:  1. Excludes adjustment for deferred stripping.  2.  Mining costs reduction reflect depletion of stockpiles late in mine life.  3.  Increase in Processing costs reflects increased electricity price starting in 2025.  4.  Includes First Nations costs.  5.  Reduction in the Site Administration charges late in the mine life reflects a reduction in mining activity.  6.  Includes adjustments for deferred stripping, royalties, and changes in inventory.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table 1-9: Operating Unit Cost Summary

Notes:  1.  Refer to Cautionary Statement on Non-IFRS Financial Performance Measures.  2.  Excludes adjustment for deferred stripping.  3.  Mining costs reduction reflect depletion of stockpiles late in mine life.  4.  Increase in Processing costs reflects increased electricity price starting in 2025.  5.  Includes First Nations costs.  6.  Reduction in Site Administration charges late in mine life reflects reduction in mining activity.  7.  Includes adjustments for deferred stripping, royalties, and changes in inventory.

Royalties included in the economic analysis are:

• Franco Nevada: 2% net smelter return;

• First Nations payments.

Taxes included in the economic evaluation are the Federal Income Tax (15%), Provincial Income Tax (10%), and the Ontario Mining Tax.  Depreciation schedules based on current depreciable balances and yearly capital additions were used to model tax depreciation for Processing and Transportation Assets as well as Mining Assets.  The tax model was completed at the Project level, which has the Detour Lake Mine as a stand-alone operating asset.

Closure costs are based on reclamation schedule extending through to the next century up to the year 2337. Progressive reclamation occurs throughout the operating period.  Reclamation activities are broken down into active closure, passive closure/flooding of the mine pit, final closure/ active discharge, and post closure/passive discharge.

The base case economic analysis assumes 100% equity financing and is reported on a 100% project ownership basis.  The base case economic analysis assumes constant prices with no inflationary adjustments.  Capital and operating costs are expressed in 2021 Canadian dollars.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The cumulative free cash flow before tax ²  is estimated at $11,141 M.  The cumulative free cash flow after tax² is $8,354 M.  At a 5% discount rate, the net present value of free cash flow before tax is $6,614 M and of free cash flows after tax is $4,968 M. Internal rate of return and payback period results are not relevant as the cumulative discounted after-tax free cash flows are never negative.  This reflects the fact that the Detour Lake Mine is already in operation and that operating cash flows are sufficient to cover sustaining and growth capital requirements.  Table 1-10 is a summary of the discounted cash flow analysis.

1.22 Sensitivity Analysis

A sensitivity analysis was performed considering variations in metal prices, exchange rates, operating costs and capital costs.  Flexing based on gold grade processed was excluded because it reflects the same sensitivity as gold price (given flat gold price assumption).  Results are shown in Figure 1-1.  Sensitivity of the Project to changes in gold price and  exchange rate are shown in Figure 1-2; the Project has positive after tax net present value under the Base Case (US$1,500/oz and 1.31 C$/US$) and under the assumptions of Mineral Reserve estimation (US$1,300/oz and 1.31 C$/US$).  The sensitivity to discount rate and the assumed discount rate range is shown in Figure 1-3.

The undiscounted free cash flow after tax³  is negative at a gold price of US$895/oz. The net present value of free cash flow after tax¹ is negative at a gold price of US$940/oz. The Project is most sensitive to changes in the gold price and exchange rate, less sensitive to operating cost changes, and least sensitive to changes in the capital cost assumptions.

1.23 Interpretation and Conclusions

Under the assumptions presented in this Report, the Project has a positive free cash flow after tax⁴ , and Mineral Reserve estimates can be supported.

1.24 Risks and Opportunities

The major risks to the Detour Lake Operations are associated with:

• Negative variations to the gold and diesel price assumptions;

• Significant additional dilution or ore losses;

• Significant delays in the assumed permitting timeline for the West Detour project;

• Changes in the geotechnical assumptions;

• Lower than planned plant production capacity.

________________________________
²Refer to Cautionary Statement on Non-IFRS Financial Performance Measures. 
³Refer to Cautionary Statement on Non-IFRS Financial Performance Measures. 
⁴Refer to Cautionary Statement on Non-IFRS Financial Performance Measures. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table 1-10: Summary of Discounted Free Cash Flow Analysis.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Note:  1.  Includes adjustment for deferred stripping.  2. Refer to Cautionary Statement on Non-IFRS Financial Performance Measures.  AISC = all-in sustaining costs.

Figure 1-1: Sensitivity of After-Tax Net Present Value to Gold Price, Exchange Rate, Operating Cost, and Capital Cost

Note:  Figure prepared by Kirkland Lake Gold, 2020.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 1-2: Sensitivity of After-Tax Net Present Value to Gold Price and Exchange Rate

Figure 1-3: Sensitivity of After-Tax Net Present Value to Discount Rate

Note:  Figure prepared by Kirkland Lake, 2020.

The major opportunities are:

• The additional mineralization in the updated West Detour model represents potential Project upside.  There is potential to redesign the Detour Lake and Detour West open pits to convert some or all of those Indicated Mineral Resources to Mineral Reserves, and thus revise the mine plan and potentially increase the mine life.  However, mining studies such as assessment of tailings and waste rock storage capacities, optimized pit planning and consideration of any future permitting requirements will have to be considered in such a conversion; 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

• Further improvements in the grade control processes with the installation of an assay laboraroty at the mine site;

• Increased level of automation in the mine operation (upgrade of the mine network to long-term evolution (LTE) enables higher level of automation);

• Use of alternative energy sources to diesel with the intent of improving business sustainability and competitiveness; 

1.25 Recommendations

A two-phase work program is proposed.  The two phases can be conducted concurrently. The total estimated budget is C$106.4 million.

The first work phase consists of the mine plan update to incorporate the 2021 West Detour Mineral Resource estimation (expanded West Detour limits).  This will require review and consideration of, amongst other mining and technical parameters, WRSF and TSF capacities, pit optimization, geotechnical and hydrogeological parameters, supporting infrastructure requirements, and capital and operating costs.  This program is estimated to require a budget of approximately C$2 million to complete mainly related to additional geotechnical drilling in the area between the Detour Lake and the West Detour pits.

The second work phase consists of exploration drilling.  The program in the near-mine area should focus on mineralization below the 800 m Level, mineralization continuing along strike and downplunge to the west of the West Detour open pit, and the potential for mineralization further east and west of the pits along the Sunday Lake Deformation Zone.  Regional exploration should target the Lower Detour area along the Lower Detour and Massicotte Deformation Zones in the vicinity of the 58N zone.  The near-mine and regional exploration programs assume drilling of 430,000 m at an all-in cost of C$243/m, for a total program cost of C$104.4 million.

2.0 Introduction

2.1 Introduction

Mr. Steve Gray, Mr. Andre Leite, Mr. Juan Figueroa, Mr. Jean-Francois Dupont, Dr. Veronika Raizman, and Mr. Paul Andrew Fournier prepared prepared a NI 43-101 Technical Report (the Report) on the Detour Lake Operations (the Detour Lake Operations, Detour Lake Mine, or the Project) for Kirkland Lake Gold Ltd (Kirkland Lake Gold).  The Detour Lake Operations are located in in northeastern Ontario (Figure 2-1).

The Detour Lake Operations consist of the operating Detour Lake Main Pit, and planned open pit operations at the West Detour and North Pits.  Mineral Resources are estimated for the Detour Lake, West Detour, Saddle, and Zone 58N areas.  Mineral Reserves are estimated for the Detour Lake and West Detour areas.  The West Detour estimate is split into the West Detour and North Pit pits.

2.2 Terms of Reference

The Report supports disclosure in the news release dated 2 September, 2021, entitled "Kirkland Lake Gold Announces 10.1 Million Ounce Increase in Measured and Indicated Mineral Resources at Detour Lake Mine".

The report was refiled to address a clerical/typographic error in the Mineral Resource tables in the Report that saw certain data inadvertently pasted into wrong cells within the tables.

Units used in the report are metric units unless otherwise noted.  Monetary units are in Canadian dollars (C$) unless otherwise stated.  All ounce units refer to troy ounces.  The Report uses Canadian English.  Mineral Resources are reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Definition Standards for Mineral Resources and Mineral Reserves (May 2014; the 2014 CIM Definition Standards).

2.3 Qualified Persons

The following Kirkland Lake Gold employees serve as the qualified persons for this Technical Report as defined in National Instrument 43-101, Standards of Disclosure for Mineral Projects, and in compliance with Form 43-101F1:

• Mr. Steven Gray, P.Geo., Exploration Superintendent;

• Mr. Andre Leite, P.Eng, Vice President Technical Services;

• Mr. Juan Figueroa, P.Geo., Manager of Mineral Resources;

• Mr. Jean Francois Dupont, P.Eng, Detour Lake Manager Metallurgy;

• Dr. Veronika Raizman, P.Geo., Manager, Reclamation & Geochemistry;

• Mr. Paul Andrew Fournier, P.Eng, Manager, Cost Accounting.

Figure 2-1: Project Location Plan

Note:  Figure prepared by Kirkland Lake Gold, 2020.

2.4 Site Visits and Scope of Personal Inspection

Mr. Steven Gray has worked for Kirkland Lake Gold as Exploration Superintendent since May 2020.  He visited the mine site on a monthly basis. His most recent site visits included July 13-16, 2021 and again on August 26, 2021.  During his most recent site visits, he communicated core drilling planning and prioritization, reviewed geology and mineralization encountered from exploration activities, accessed core processing operations and sample dispatch methodology, and outlined future regional geological activities. During these visits to site also he also inspected core drill rigs, drill collar locations and site  remediations, reviewed infrastructure requirements, staffing levels, employee development and health and safety statistics

Mr. Andre Leite worked for the Detour Lake Mine as a Technical Service Manager from October 2018 to April 2021.  He is currently Vice President of Technical Service based at Kirkland Lake Gold's Timmins hub office and regularly visits the mine site.  His most recent site visit in 2021 was on September 13, 2021.  During that site visit, he participated in operational management meetings.  During earlier site visits, he reviewed weekly and daily mine plans, held discussions on grade control processes and results.

Mr. Juan Figueroa has worked for Kirkland Lake Gold as a Manager of Mineral Resources since June 2020.  His most recent site visit was from July 21-23, 2020.  During that site visit, he examined the drilling exploration advances impacting the Saddle and West Detour Mineral Resource estimates, the drilling plans for the remainder of 2020, and reviewed the grade control process implemented by the geology department in the Detour Lake pit.

Mr. Jean Francois Dupont has worked at the Detour Lake Mine from 2011 and has been based at the Detour Operation since that time to the Report effective date.  Mr Dupont was directly involved in the engineering, construction and commissioning of the Detour Lake Mine processing plant, and has been involved with plant operations since commissioning.

Dr. Veronika Raizman was based at the Detour Lake Mine from 2016 to 2020, and now works from Kirkland Lake Gold Inc.'s Toronto corporate office.  Her most recent site visit was from March 12 to 19, 2020.  During that site visit, Dr. Raizman performed her regular duties with respect to the management of the Detour Lake Mine's geochemical monitoring, reclamation programs, and regulatory permitting and compliance.

Mr. Paul Andrew Fournier's most recent site visit was from July 2-15, 2020.  During this visit, he viewed the mine services facility, the exterior of the processing plant, and Little Hopper Lodge.  He had discussions with site personnel for the preparation of the financial model for the quarterly (6+6) forecast.

2.5 Effective Dates

There are a number of effective dates pertinent to the Report, as follows:

• Most recent information on the ongoing drilling program:  September 30, 2021;

• Most recent information on mineral tenure and surface rights:  October 12, 2021;

• Geotechnical mine design parameters for Detour Lake pit: May 5, 2020;

• Geotechnical mine design parameters for West Detour and North Pit: September 26, 2019;

• Database close-out date for purposes of Mineral Resource estimation:

o Detour Lake: April 24, 2020;

o West Detour: July 26, 2021;

o North Pit:  November 24, 2016;

o Zone 58N:  February 2018;

• Effective date of the Mineral Resource estimate supporting Mineral Reserves:

o North Pit:  December 31, 2020;

o Detour Lake:  December 31, 2020;

o West Detour: December 31, 2020;

• Effective date of the Mineral Resource estimates:

o Zone 58N:  December 31, 2020;

o North Pit:  December 31, 2020;

o West Detour: July 26, 2021;

o Detour Lake:  July 26, 2021;

• Effective date of the Mineral Reserve estimates:  December 31, 2020;

• Effective date of the financial analysis that supports the Mineral Reserves: December 31, 2020.

The overall Report effective date is taken to be the date of the updated Mineral Resource estimate for Detour Lake and West Detour and is July 26, 2021. 

2.6 Information Sources and References

Reports and documents listed in Section 2.7, Section 3 and Section 27 of this Report were used to support preparation of the Report.  Additional information was provided by Kirkland Lake Gold personnel as required.

Information pertaining to surface rights, royalties, environmental, permitting and social considerations, marketing and taxation were sourced from Kirkland Lake Gold experts in those fields as required.

2.7 Previous Technical Reports

Kirkland Lake Gold has previously filed the following technical report on the Project:

• Leite, A., Dupont, J.F., Raizman, V., and Fournier, P.A., 2020:  Detour Lake Operations, Ontario, Canada, NI 43-101 Technical Report:  technical report prepared for Kirkland Lake Gold, effective date 30 December, 2020.

The following reports were filed by Detour Gold Corporation (Detour Gold):

• Kallio, E.A., 2006:  Technical Report for the Detour Lake Mine Option Property: technical report prepared for Detour Gold Corporation, effective date 21 September, 2006;

• Risto, R., Breede, K., el Rassi, D., and Kociumbas, M.W., 2008:  Technical Report and Mineral Resource Estimate for the Detour Lake Mine Option Property, Ontario:  technical report prepared for Detour Gold Corporation, effective date 25 January, 2008;

• Risto, R., Breede, K., Live, P., Castro, L., and Melis, L., 2008:  Technical Report and Mineral Resource Estimate Update for the Detour Lake Mine Option Property, Ontario:  technical report prepared for Detour Gold Corporation, effective date 18 August, 2008;

• Desautels, P., and Zurowski, G., 2009:  Technical Report and Mineral Resource Estimate on the Block A Property, Ontario, Canada: technical report prepared for Trade Winds Ventures Inc. and Detour Gold Corporation, effective date 9 July, 2009;

• Crépeau, R., Brimage, D., Allaire, A., Jacobs, C.A., Houde, D., Li, D., Nakai-Lajoie, P., Live, P., Dagbert, M., Melis, L.A., Saucier, G., Noack, G., and Daniel, S.E., 2009:  Technical Report, Pre-Feasibility Study of the Detour Lake Project, Ontario:  technical report prepared for Detour Gold Corporation, effective date 19 October, 2009;

• Allaire, A., Dagbert, M., Daniel, S.E., Laferrière, A., Li, D., and Live, P., 2010:  Technical Report, Feasibility Study of the Detour Lake Project, Ontario:  technical report prepared for Detour Gold Corporation, effective date 30 June, 2010;

• Allaire, A., Dagbert, M., Laferrière, A., and Live, P., 2011:  Technical Report, Mineral Resource and Mineral Reserve Update of the Detour Lake Project, Ontario:  technical report prepared for Detour Gold Corporation, effective date 15 March, 2011;

• Ritchie, D.G., Allaire, A., Live, P., Dagbert, M., and Dupéré, M., 2012:  Detour Lake Mine - NI 43-101 Technical Report:  Detour Lake Updated Mine Plan NI 43-101 Technical Report:  technical report prepared for Detour Gold Corporation, effective date 18 October, 2012;

• Allaire, A., Live, P., Dupéré, M., Camus, Y., and Ritchie, D.G., 2014:  technical report prepared for Detour Gold Corporation, effective date 4 February, 2014;

• Anwyll, D., Croal, A.G., McMullen, J., and Ritchie, D.G., 2016:  Detour Lake Mine - NI 43-101 Technical Report:  technical report prepared for Detour Gold Corporation, effective date 25 January, 2016;

• Anwyll, D., Bassotti, M., Daigle, P., Janusauskas, D., McMullen, J., Sirois, R., and Wallin, R., 2018:  Detour Lake Operation, Ontario, Canada, NI 43-101 Technical Report:  technical report prepared for Detour Gold Corporation, effective date 27 June, 2018.

The following reports were filed by Pelangio Mines Inc. (Pelangio):

• Kallio, E.A., 2005:  Technical Report for the Detour Lake Mine Option Property: technical report prepared for Pelangio Mines Inc., effective date 10 May, 2005;

• Kallio, E.A., 2006:  Technical Report for the Detour Lake Mine Option Property: technical report prepared for Pelangio Mines Inc., effective date 21 September, 2006;

• Risto, R., Breede, K., el Rassi, D., and Kociumbas, M.W., 2008:  Technical Report and Mineral Resource Estimate for the Detour Lake Mine Option Property, Ontario:  technical report prepared for Pelangio Mines Inc., effective date 25 January, 2008;

• Risto, R., Breede, K., Live, P., Castro, L., and Melis, L., 2008:  Technical Report and Mineral Resource Estimate Update for the Detour Lake Mine Option Property, Ontario:  technical report prepared for Pelangio Mines Inc., effective date 18 August, 2008.

The following reports were filed by Trade Winds Ventures Inc. (Trade Winds):

• Desautels, P., 2009:  Technical Report and Mineral Resource Estimate on the Gowest Property, Ontario, Canada:  technical report prepared for Trade Winds Ventures Inc., effective date 28 April, 2009.

• Desautels, P., and Zurowski, G., 2009:  Technical Report and Mineral Resource Estimate on the Block A Property, Ontario, Canada:  technical report prepared for Trade Winds Ventures Inc. and Detour Gold Corporation, effective date 9 July, 2009;

• Desautels, P., Zurowski, G., and Holloway, A., 2011:  Technical Report and Mineral Resource Update on the Block A Property, Ontario, Canada:  technical report prepared for Trade Winds Ventures Inc., effective date 14 February, 2011.

3.0 Reliance on Other Experts

This section is not relevant to this Report.

4.0 Property Description and Location

4.1 Introduction

The Project is situated approximately 300 km northeast of Timmins and 185 km by road northeast of Cochrane. 

The Project centroid is at approximately 590,000mE 5,540,000mN NAD 83 Datum, Zone 17 within NTS areas 32E13.

The Detour Lake open pit mine is centered at UTM 594000E, 5542000N (NAD 83 Zone 17).

4.2 Property and Title in Ontario

This section provides a general overview of mineral-related law and title in Ontario, sourced from public domain documentation, including Natural Resources Canada (2015), The Fraser Institute (2020), Norton Rose Fulbright, (2013), and the Ontario Mines Act (1990). 

4.2.1 Introduction

Until 1913, surface rights and mineral rights were acquired with land purchase.  At that time, the Ontario Government enacted legislation reserving land mineral rights to the Crown and granting leases to individuals or companies seeking to extract minerals.  Where mineral rights are privately owned due to granting prior to 1913, they can be sold independently of surface rights, so that surface and mineral rights on the same property can be held by different owners.

The Ministry of Energy, Northern Development and Mines (ENDM) and the Ontario Ministry of Natural Resources and Forestry (MNRF) act as the two main regulatory bodies that have combined into Ministry of Northern Development, Mines, Natural Resources and Forestry (NDMNRF).  The Canadian Federal Government may also be involved in the mining process where First Nations matters arise, or where the subject lands are federally regulated such as when the lands are classified as navigable bodies of water.

4.2.2 Mineral Tenure

Mining Claim

Historically, a mining claim was a square or rectangular area of open Crown land (land that belongs to the Province of Ontario) or Crown mineral rights that a licenced prospector marks out with a series of claim posts and blazed lines which could range in size from 16 ha (a one-unit claim) to 256 ha (a 16-unit claim). 

The mining claims in the Sudbury area are administered under Mining Act, R.S.O. 1990, c. M.14 as well as several regulations thereunder.

Mining Lease

A mining claim can be converted into a mining lease.  To convert a mining claim into a lease an application letter must be submitted to the Provincial Recording Office's Technical Services Unit any time after the fifth unit of assessment work has been performed (cash payment may be made in lieu of the second to fifth unit of assessment work) on the land and the work has been submitted and approved.  After submitting the application letter, the land covered by the mining claims must be surveyed. The applicant may also request that the surface rights be included in the Mining Lease where the surface rights are held by the Crown.  Where the surface rights are privately held, the lessee of the mineral rights may need to acquire the surface rights if required for development or production purposes.

A lease grants its owner title and ownership to the land, permits the extracting and sale of extracted resources and removes the requirement to perform yearly assessment work.

To maintain a lease, rent must be paid annually.  A lease expires after 21 years but can be renewed if the lease-holder can demonstrate continuous production of minerals for at least one year since the issuance or if the lease-holder can show that it has taken a reasonable effort to bring the property into production.  A mining lease can also be renewed on the basis of contiguity with other mining leases where production has occurred.

A mining lease cannot be transferred or mortgaged by the lessee without the prior consent of the NDMNRF.  Transfers require the lessee to submit various documentation and pay a fee.

Patented Claims

The owner of freehold lands in Ontario holds a fee-simple real property interest.  Historically, the holder of a mining claim interested in removing minerals from the ground could, instead of obtaining a mining lease, apply to the NDMNRF to acquire the freehold interest in the subject lands through the granting of a mining patent.

Such patents can include surface and mining rights, or may only comprise mining rights.  They give the patentee all of the Crown's title to the subject lands and to all mines and minerals relating to such lands, subject to any reservations set out in the patent.  Patented claims are subject to annual Ontario mining taxes and, where surface rights are held, Ontario mineral land taxes.

No regulatory consent is required for the patentee to transfer or mortgage those lands other than Planning Act approval where the transferred lands are adjacent to other lands held by the same party.

Mining Licence of Occupation

These mining licences of occupation allow the holder to use the land in the manner specified in each licence, including the right to dig, excavate and remove ores and minerals from and under the land.  The Province of Ontario has the right to revoke licences of occupation on 30 days prior notice. 

4.2.3 Ontario Modernizing the Mining Act Process

Information in this section was derived from the NDMNRF website, and the QP has not independently verified the information.

Ontario has fully implemented the third phase of the Ontario government's Modernizing the Mining Act (MAM) process.  This phase:

• Moves Ontario's mining lands administration systems from ground staking and paper map staking to online registration of mining claims

• Creates an online Mining Land Administration System (MLAS) that enhances client access to Ontario's mining lands data and improves their ability to manage their files online.

On April 10, 2018, Ontario converted Ontario's manual system of ground and paper staking, and maintaining unpatented mining claims to an online system.  All active, unpatented claims were converted from their legally defined location by claim posts on the ground or by township survey to a cell-based provincial grid.  Mining claims are now legally defined by their cell position on the grid and coordinate location in the MLAS Map Viewer.  These changes bring greater accuracy and certainty to the location of mining claims, greater certainty of rights and interests, as well as flexible management of land assets.

Annual assessment work requirements remain unchanged, despite new cell sizes being 11% to 50% larger than the size of traditional claim units.  Assessment work requirements are C$400 per cell claim and C$200 per boundary claim or any claim that is encumbered.  Where work has not been completed ahead of the due date, claims forfeit to the Crown.

Under the MLAS system, registering a mining claim is now completed by paying a single registration fee of $50 per cell. 

4.2.4 Surface Rights

Surface rights refer to any right in land that is not a mining right.  The process of acquiring surface rights for mining purposes depends on the owner of the rights:

• If the surface rights are owned by the claim holder, then no action is required

• If the surface rights are owned by the Crown, then the ownership of the surface rights will be granted to the claim holder during the lease application process as requested by the claim holder

• If the surface rights are privately owned by an individual or company, then an agreement to allow the claim holder to use the land must be made with the surface rights holder.  The agreement should outline the compensation given if the land covered by the surface rights sustains any damages. 

Confirmation of an agreement with the surface rights owner is required for grant of a mining lease, or an order of the Mining Lands Commissioner indicating that surface rights compensation, if any, has been paid, secured or settled must be provided.

4.2.5 Environmental Considerations

The Ontario Environmental Assessment Act is the legislation most often applied to environmental aspects of mining projects in Ontario.  Mining project components may also be subject to the Federal Canadian Environmental Assessment Act. 

Projects that are directly undertaken by a public agency; are undertaken on their behalf to fulfill a public agency responsibility or involve a public agency resource (for example, use of Crown lands, funding from a government agency, or impact on resources under government jurisdiction such as water bodies, fish habitat, timber or Mineral Resources) are required to follow an environmental assessment (EA) process.  Both the Provincial and Federal EA acts generally apply.  Both EA acts provide opportunities for varying levels of effort for conducting an EA, with the most intensive and longer-term processes required either for those projects that have the greatest potential to cause significant adverse environmental effects, or which are relatively unique, with perhaps the scope of potential impacts unknown.

A minimum amount of six months should be anticipated for completion of an environmental assessment, with a likely need of one year or more from the start of the process through to receipt of approval from the relevant agency.

4.2.6 Closure Considerations

All land affected by mining development activity must be rehabilitated after the activity has finished.  A closure plan must be developed and acknowledged by the NDMNRF before mine development can begin.  The plan outlines how the affected land will be rehabilitated and the costs associated with doing so.  A financial guarantee equal to the estimated cost of the rehabilitation work is held in trust by the NDMNRF that is included with the submission of a closure plan.

4.2.7 First Nations Considerations

Section 35 of the Canadian Constitution Act, 1982, recognizes and protects Aboriginal and treaty rights in Canada.  The Crown has a legal duty to engage in meaningful consultation whenever it has reason to believe that its decisions or actions might infringe upon recognized aboriginal or treaty rights.

NDMNRF has the responsibility for coordinating the Crown's consultation efforts on decisions relating to mining and mineral exploration.  If the project requires approvals or decisions by other Ministries with mineral development regulatory authority, there will be a coordinated approach to the government's consultation with Aboriginal communities.

4.2.8 Fraser Institute Survey

Kirkland Lake Gold has used the Investment Attractiveness Index from the 2020 Fraser Institute Annual Survey of Mining Companies report (the Fraser Institute survey) as a credible source for the assessment of the overall political risk facing an exploration or mining project in Ontario. 

Kirkland Lake Gold used the Fraser Institute survey because it is globally regarded as an independent report-card style assessment to governments on how attractive their policies are from the point of view of an exploration manager or mining company, and forms a proxy for the assessment by industry of political risk in Ontario from the mining perspective.

Overall, Ontario ranked 20^th out of the 77 jurisdictions in the survey in 2020 for investment attractiveness, 31^st for policy perception, and 20^th for best practices mineral potential.

4.3 Project Ownership

4.3.1 Ownership History

The original ownership interest was held by Amoco Canada Petroleum Company Ltd. (Amoco).  In 1978, Amoco signed a joint venture (JV) agreement with Campbell Red Lake Mines (Campbell) and Dome Mines Ltd. (Dome).  In 1987, Campbell, Dome and Placer Development merged to become Placer Dome Inc. (Placer).  Placer acquired Amoco's interest in the JV. 

In December 1998, Pelangio-Larder Mines Limited (Pelangio-Larder) and Franco-Nevada Mining Company Limited (Franco-Nevada) formed the Detour Lake Joint Venture and acquired the Mine Property from Placer Dome (CLA) Ltd.  The Detour Lake Joint Venture also acquired certain parts of the Detour Exploration Lands surrounding the Mine Property pursuant to an assignment of the letter agreement dated as of September 28, 1998, between Pelangio-Larder and Placer.

Marl Resources Corp. (Marl Resources), the predecessor company to Pelangio Mines Inc. (Pelangio), acquired the majority of Pelangio-Larder's assets, including the Pelangio-Larder interest in the Detour Lake Joint Venture.  Franco-Nevada's Project interest, due to merger and acquisition activity, passed to Newmont Mining Corporation of Canada Limited (Newmont).

In May 2002, Pelangio completed the purchase of all of Newmont's interest in the Detour Lake Joint Venture, subject to the retention of a 2% net smelter return (NSR) royalty retained  by Newmont on the Mine Property and on certain claims staked by Pelangio (Blocks A to E).  Newmont subsequently assigned its 2% NSR royalty to Franco-Nevada.

In June 2002, Pelangio purchased the Purchased Claims from a prospector subject to the retention of a 2% NSR by the selling prospector. 

In September 2003, Pelangio granted Trade Winds Ventures Inc. (Trade Winds) an option to acquire a 50% interest in Block A, located immediately west of the Mine Property.  Trade Winds earned a 50% interest in Block A on December 31, 2006. 

Detour Gold was incorporated on July 19, 2006 to acquire the mineral tenures hosting the Detour Lake deposit, through a Purchase Agreement with Pelangio.  All conditions set out in the Purchase Agreement, including the completion of an initial public offering, were fulfilled on January 31, 2007, and the titles held by Pelangio were transferred to Detour Gold.  A JV agreement with Trade Winds was signed on April 8, 2009.

The option on the Mine Property was exercised on October 30, 2008, when Detour Gold became the sole owner of all related surface rights, titles, and permits that were transferred from Goldcorp Canada Ltd. (Goldcorp), as successor to Placer Dome.  In connection with the purchase of the Mine Property, Goldcorp held a 1% NSR on the Mine Property, which Detour Gold purchased for $1 million in November 2012.

In September 2010, Detour Gold acquired the Aurora claims blocks from Conquest Resources, and entered into an Option and Joint Venture Agreement to acquire a 50% interest in Conquest's Sunday Lake claim block.  The remaining interest in the Sunday Lake claims block was acquired in December 2014, giving Detour Gold a 100% interest in those claims.

In December 2011, Detour Gold acquired Trade Winds Ventures Inc., giving Detour Gold a 100% interest in the Block A and Gowest properties.  Detour Gold amalgamated with its wholly-owned subsidiary Trade Winds effective January 1, 2014.

On January 31, 2020, Kirkland Lake Gold completed the acquisition of Detour Gold and Detour Gold became a wholly-owned subsidiary of Kirkland Lake Gold.

On January 2, 2021, Detour Gold was amalgamated with Kirkland Lake Gold Inc., a wholly-owned subsidiary of Kirkland Lake Gold and the amalgamated entity was renamed Kirkland Lake Gold Inc.

4.3.2 Current Ownership

The Project is wholly-owned by Kirkland Lake Gold Inc., a subsidiary of Kirkland Lake Gold.

4.4 Mineral Tenure

The 646 km² Project area forms one contiguous group of mining patents, mining leases and cell mining claims in the District of Cochrane, Ontario, with a small group of cell claims in Massicotte Township, Québec.  The Detour Lake Operations are within the following mining leases and mining patents:  LEA-109295, LEA-107399, LEA-109361, LEA-109040, LEA-107400, LEA-107392, LEA-108893, LEA-107394, LEA-107174, LEA-108269, LEA-109382, LEA-107398, LEA-107395, LEA-107396, LEA-107397, LEA-107393, LEA-107402, LEA-107397, LEA-107401, LEA-107404, PAT-5479, PAT-5477, PAT-5478, PAT-5482, PAT-5485, PAT-5484, PAT-5483, PAT-5481, PAT-5476, and PAT-5480.

A summary of the mineral tenure is provided in Table 4-1 and shown in Figure 4-1 and Figure 4-2. 

Appendix A contains the details of the individual mineral tenures, including location, area, expiry date and any associated royalties.  More detailed location maps are provided with the claims tables in Appendix A.

Table 4-1: Mineral Tenure Summary Table

Figure 4-1: Mineral Tenure Summary Location Plan

Note:  Figure prepared by Kirkland Lake Gold, 2020.  Appendix A includes subset figures that more clearly show the individual claim numbers.

Figure 4-2: Detour Lake Operations Mining Lease and Mining Patent Location Plan

Note:  Figure prepared by Kirkland Lake Gold, 2020.  Appendix A has subset figures that explain the infrastructure shown.

4.4.1 Patented Documents

The patented parcels of land are the most secure form of land tenure and are subject to an annual mining tax payable to the Crown.  The patented lands are described by the legal survey of individual mining claims and surveyed mining locations.

4.4.2 Leasehold Documents

The leasehold mining lands consist of 21-year mining leases issued for mining claims that were legally surveyed as individual mining claims or defined by the perimeter survey of groups of mining claims.  Each perimeter survey is given a Certified Legal Manager (CLM) designation to describe the surveyed group of claims.  Leaseholders are subject to an annual rental payable to the Crown.  The Mining Act (Ontario) contains provisions for the renewal of 21-year mining leases.  Applications for renewal are subject to review and consent by the NDMNRF.

4.4.3 Cell Mining Claims

Mining claims are legally defined by their cell position on the grid and coordinate location in the Mining Lands Administration System (MLAS) map viewer.  The unpatented mining claims (cell mining claims) held by Kirkland Lake Gold do not confer any right, title, interest or claims in or to the mining claims other than the right to proceed as is in the Mining Act (Ontario). 

Upon registering cell mining claims (cells), Kirkland Lake Gold must perform and file exploration assessment work and apply on those cells assessment work credits to maintain them in good standing.  The first unit of assessment work of $400 per 20 ha is required by the second anniversary date of the recording of the cell and an additional unit is required to be performed and filed for each year thereafter.  Until a mining lease for the mining claims is issued, the Kirkland Lake Gold does not have the right to remove or otherwise dispose of any minerals found in, upon or under the mining claim.

4.4.4 Claims

A claim in Québec provides the stakeholder with a two-year right to explore within the claim holdings for any mineral substance with exceptions.  After the initial two-year period claims can be renewed for an additional two-year term on certain conditions including that sufficient assessment work is performed on the claims or payment is made in lieu.

4.5 Surface Rights

Kirkland Lake Gold has 30 leases and 10 patents totaling 18,574.442 ha of surface rights on the Detour Lake Project.  The patented lands are subject to a yearly annual mining tax payable to the Crown.  The 21-year mining leases are subject to an annual rental payable to the Crown and applications for renewal are subject to review and consent by the MNDM.  Fourteen leases totaling 4,679.946 ha will require renewal in 2023.

Kirkland Lake Gold's surface rights are sufficient for all the infrastructure and operation of the mine.  The infrastructure included the construction of a 230-kV transmission line, a processing plant facility, various mine site buildings (mine services facility, bulk explosives plant, wash bay, fuel and lube island, etc.), a permanent camp, and new roads to connect the infrastructure buildings. 

4.6 Water Rights

Kirkland Lake Gold does not exclusively hold water rights in the region.  As part of the ongoing environmental compliance Kirkland Lake Gold is required to capture all site runoff from stockpiles and the open pits. Water taking from groundwater and freshwater sources is regulated by the Ontario Ministry of Environment, Conservation and Parks (MECP) via Permits to Take Water (PTTW). The Detour Lake Mine has a number of active PTTW, which are renewed at the required regulatory frequency in order to support activities over the life-of-mine (LOM).  Since this water is required to be captured it puts the site water balance in a surplus over the LOM, providing sufficient water to be used for processing in the mill, with the excess being discharged to the environment under the permitted discharge conditions for the operations.

4.7 Royalties and Encumbrances

The Project is subject to the royalties listed in Table 4-2.  Claim blocks that are subject to royalties are provided in Appendix A and are shown in Figure 4-3.

Kirkland Lake Gold has an option to acquire 50% of the royalty on the Gowest property at any time up to the date that is one year from the date from which "commercial production" commences on the Gowest property.

Prism Resources Inc. (Prism) claims it is entitled to a 7.5% net profit interest on the Aurora and Sunday Lake properties (the NPI).  Kirkland Lake Gold disputes the claim made by Prism and has asserted that the NPI does not in fact exist.  Prism commenced proceedings against Detour Gold Corporation in British Columbia and in August 2018 the Supreme Court of British Columbia declined to exercise jurisdiction and the proceeding was stayed.  In April 2019, Prism filed a statement of claim against Detour Gold Corporation and applied for a summary judgement motion against Detour Gold Corporation.  In April 2021 the Ontario Superior Court of Justice ruled in favour of Prism, asserting that the NPI is enforceable against Detour Gold Corporation. In May 2021, Kirkland Lake Gold filed an appeal of the summary judgement ruling issued by the Superior Court to the Ontario Court of Appeal.  The appeal is scheduled for January 2022.

The Detour Lake Operations are not subject to any other back-in rights payments, agreements or encumbrances.

Table 4-2: Royalty Summary Table

Figure 4-3: Detour Lake Property Area Map Showing Areas with Royalty Payments

Note:  Figure prepared by Kirkland Lake Gold, 2020

4.8 Permitting Considerations

Permitting considerations for operations are discussed in Section 20.

Exploration activities require water-taking permits to be obtained to provide the necessary water for exploration drilling activities. To date, all such permits have been granted as required.

4.9 Environmental Considerations

Environmental considerations for operations are discussed in Section 20.

Current exploration liabilities consist with respect to the environment primarily consist of the potential for fuel and lubricant spills and the risk of fire during the drier months resulting from heavy equipment.

Liabilities and closure considerations associated with the current operations are provided in Section 20.

4.10 Social License Considerations

Social licence considerations for operations are discussed in Section 20.

4.11 Comment on Property Description and Location

To the extent known to the QP, there are no other significant factors and risks that may affect access, title, or the right or ability to perform work on the Project that have not been discussed in this Report.

5.0 Accessibility, Climate, Local Resources, Infrastructure, and Physiography

5.1 Accessibility

From the town of Cochrane (population of approximately 5,000 residents), the Project is easily accessible by the Detour Lake Mine road, the northern extension of Highway 652.  The first 151 km on Highway 652 is paved surface, followed by 34 km of well-maintained gravel surfaced road to the mine site.  Road access is available year-round.

The closest major airport to the site is at Timmins, Ontario, approximately 61 km to the southeast.

Site access is controlled by a 24 hour a day manned security gate to prevent the general public accidentally accessing the active mining areas.

5.2 Climate

The climate in the Project area is characterized by cold winters and mild summers. 

The mean annual temperature is estimated at 0.5°C, with average daily temperatures ranging from -18.7°C in January to 16.5°C in July. 

The average total annual precipitation is estimated at 862 mm with approximately 30% falling as snow, and the greatest precipitation contribution occurring as rain during June through October.

The predominant wind direction is from the west. 

Mining and exploration activities are conducted year-round.

5.3 Local Resources and Infrastructure

The closest settlement to the Project is the Town of Cochrane, Ontario. 

The region benefits from a strong contractor and supplier base to the mining industry.  Skilled labour and suppliers are readily available in Cochrane, Timmins, Kapuskasing, Iroquois Falls, and Kirkland Lake Gold.

Additional information on site infrastructure is provided in Section 18.

5.4 Physiography

Site topography is subdued with maximum local relief of approximately 30 m.  The elevation ranges from approximately 260-288 metres above sea level.  There is a pronounced north/south fluting of the landscape consistent with the general direction of the most recent glaciations in this area. 

Areas of higher relief are sparsely wooded with jack pine, black and white spruce, balsam fir, trembling aspen, and white birch.  Areas that are slightly lower in relief are poorly drained and characterized by muskeg. 

There is very little bedrock outcrop and much of the Project area is overlain by thick accumulations of glacial material that includes till and glaciofluvial material (poorly sorted sand with lenses of gravel). 

Numerous small streams linking elliptical lakes and ponds, generally oriented parallel to the pattern of glacial fluting.  Numerous small and shallow lakes are found within the Project area, the largest being Sunday Lake, with a surface area of approximately 2.8 km².

5.5 Sufficiency of Surface Rights

There is sufficient surface area for the open pits, waste rock storage facilities (WRSFs), plant, TMA; (cells one, two and three), associated infrastructure, and other operational requirements for the LOM and mine plan discussed in this Report.

6.0 History

6.1 Exploration History

The exploration history is summarized in Table 6-1.

6.2 Production History

During the initial 17-year mine life from 1987-1999, production is estimated at 1.7 Moz Au from about 14.3 Mt grading 3.82 g/t Au, with mill recovery averaging 93.1%.

Production during the Detour Gold ownership period (2013-30 January 2020) is estimated at 3.6 Moz Au from about 135.5 Mt grading 0.90 g/t Au, with mill recovery averaging 90.1%.

Production since Kirkland Gold became Project operator is provided in Table 6-2.

Table 6-1: Exploration History

Table 6-2: Production History, Kirkland Gold

7.0 Geological Setting and Mineralization

7.1 Regional Geology

The regional geology description is summarized from Oliver et al., (2011).

The Project is located within the northwestern portion of the Abitibi Greenstone Belt, which lies, in turn, within the eastern part of the Wawa-Abitibi sub-province, a Neoarchean granite-greenstone sub province in the southern Superior Province of the Canadian Shield craton.  The Abitibi Greenstone Belt consists of east-west-trending synclines of felsic to ultramafic volcanic rocks.  Intervening domes are cored by syn-volcanic tonalite and gabbrodiorite rocks and alternate with east-west-trending bands of late tectonic turbiditic and conglomeratic sedimentary rocks.  Most of the volcanic and sedimentary strata dip vertically and are commonly bound by abrupt, east-west-trending faults with varied dips.

The stratigraphy of the Abitibi Greenstone Belt is subdivided into earlier volcanic-dominated episodes that include the Pacaud assemblage (2770-2736 Ma), the Deloro assemblage (2730-2724 Ma), the Stoughton-Roquemaure assemblage (2723-2720 Ma), the Kidd-Munro assemblage (2719-2711 Ma), the Tisdale assemblage (2710-2704 Ma), and the Blake River assemblage (2704-2695 Ma).  These sequences are unconformably overlain by turbidites and calc-alkaline volcanic rocks of the Caopatina assemblage (ca. 2700 Ma) in the north and the Porcupine assemblage (2690-2685 Ma) in the south.  These units in turn are unconformably overlain by coarse clastic and alkaline volcanic rocks of the Opemisca assemblage (ca. 2692 Ma) in the north and the Timiskaming assemblage (2676-2670 Ma) in the south.  A regional geology figure is included as Figure 7-1.

7.2 Project Geology

In the Project area, the greenstone-granite architecture is partially aligned and disrupted along a linear, east-west-trending belt that defines the position of the Sunday Lake Deformation Zone. 

Supracrustal rocks within the Project area consist of a thick sequence of mafic to ultramafic lithologies, which are predominantly volcanic in origin, and are part of the Deloro assemblage.  They occur within regional synclinal-anticlinal fold structures traced for over 30 km across the Project and are in structural contact to the south with the younger sediments of the Caopatina assemblage.  These rocks are bounded to the north and west by the Opatica basement gneissic rocks.  To the east and south, the Deloro assemblage is intruded by several large, weakly foliated granodioritic to tonalitic intrusions which are intersected by numerous local felsic to mafic dykes, sills and younger regional Proterozoic diabase dykes.

7.2.1 Lithologies

The major lithologies in the Project area are summarized in Table 7-1.  A Project-scale geology plan is provided in Figure 7-2. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-1: Regional Geology Plan

Note:  Figure from Oliver et al., (2011).

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Table 7-1: Lithology Table

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-2: Project Geology Map

Note:  Figure prepared by Kirkland Lake Gold, 2020. SLDZ = Sunday Lake Deformation Zone; MDZ = Massicotte Deformation Zone; LDDZ = Lower Detour Deformation Zone.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The Deloro Assemblage, north of the SLDZ, is sub-divided into the Upper Detour Lake Formation, a volcanic assemblage dominated by tholeiitic basalt (mainly high-Mg massive and high-Fe pillowed flows); and the Lower Detour Lake Formation, an ultramafic-dominant komatiitic and high-Mg tholeiitic volcanic and intrusive assemblage. 

Where the komatiitic lithologies are in contact with the Sunday Lake Deformation Zone, they are highly deformed and altered into talc-chlorite schist.  The contact is highly mylonitized, mineralized and silicified and hosts a strongly deformed felsic to intermediate dyke-like body known locally as the "chert marker horizon". 

The chert marker horizon is not a chert unit, but rather a fine-grained felsic volcaniclastic unit and/or a series of intensely silicified and sulphidized volcanic rocks and intermediate sills and dykes.  It occurs between mafic-dominated volcanic rocks of the Upper Detour Formation (hosts hanging wall mineralization) and ultramafic volcanic rocks of the Lower Detour Formation (hosts footwall mineralization).

7.2.2 Structure

The major structural feature is the 30 km-long Sunday Lake Deformation Zone, an east-west-trending, steeply north-dipping deformation corridor.  The zone marks the northern contact between the Caopatina assemblage sedimentary rocks and the underlying Deloro assemblage volcanic rocks.  Mineralization at Detour Lake and West Detour is spatially related to Sunday Lake Deformation Zone structures.

Kinematic indicators confirm sinistral-reverse north over south motion along the Sunday Lake Deformation Zone. A regional east-west trending structure, the Massicotte Deformation Zone is recognized several kilometres to the south of the Sunday Lake Deformation Zone and extends for over 30 km in strike length.  It marks the southern contact between the Caopatina assemblage sedimentary rocks and the underlying Deloro assemblage volcanic rocks.

The third major structure is the Lower Detour Deformation Zone, a 30 km long, east-west-trending, and steeply south-dipping one that separates Caopatina assemblage sedimentary rocks and the underlying Deloro assemblage volcanic rocks.  The 58 North Zone (58N) occurs immediately south of the Lower Detour Deformation Zone.

The youngest structures are a series of 120-145° trending faults, which are locally intruded by Proterozoic-age diabase dykes.

Two east-trending synform-antiform pairs are developed in the volcanic assemblage, the North Walter Lake Synform and the Airstrip Antiform (Figure 7-3).  These folds are tight, upright, slightly overturned, and south-facing.  A later fold set consists of broad open folds that have axial traces striking at approximately 145°,and plunging 10-35° to the northwest.  The inter-limb distances of these folds are approximately 8-12 km.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-3: Local Structural Setting

Note:  Figure from Oliver et al., 2011.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

7.2.3 Metamorphism

All rock units have undergone upper greenschist to lower-grade amphibolite metamorphism.

7.2.4 Alteration

All lithological units are hydrothermally altered proximal to major deformation zones. 

Strong secondary biotite is developed in mafic rocks.  Talc-actinolite chlorite assemblages formed in ultramafic sills next to the chert marker horizon and across the northern edge of the Detour Lake deposit and through the West Detour deposit.  The footwall magnesium-rich komatiitic volcanic rocks show alteration to schistose rocks with a mineral assemblage of chlorite-talc-calcite-tremolite/actinolite-biotite.  Silicification may overprint the biotite alteration or occur as an intense pinkish halo with associated potassic feldspar flooding.

7.2.5 Mineralization

There are two recognized episodes of gold mineralization at the Detour Lake and West Detour deposits.

The first episode consists of a wide and generally auriferous sulphide-poor quartz vein stockwork formed in the hanging wall of the Sunday Lake Deformation Zone.  The sulphide-poor quartz vein stockworks observed in the hanging wall have sub-vertical north or south dips and are parallel to a series of east-west trending high strain zones.  These veins form a weak stockwork and are boudinaged and/or folded.

The second episode is a stage of gold mineralization overprinting the early auriferous stockwork, principally in the hanging wall of the Sunday Lake Deformation Zone, with a higher sulphide content.  The sulphide-rich gold mineralization predominantly fills structural sites in deformed quartz veins, fractures and veins crosscutting the foliation fabric but also in pillow breccias and selvages.  The distribution of sulphide-rich mineralization is strongly controlled by the geometry of kinematic orientation (i.e., pyrite and pyrrhotite concentrations have a shallow westerly plunge similar to the plunge of the main flexure zone in the Sunday Lake Deformation Zone at an angle of about 40° (in the area of the former Campbell pit), shallowing to approximately 10° further to the west).

7.3 Deposit Descriptions

7.3.1 Detour Lake

Dimensions

Mineralization at Detour Lake is hosted within a broad corridor.  In mine grid coordinates the mineralization extends from 16,900E to 20,650E, 19300N to 20,650N and 5,500 m elevation to 6,300 m elevation.  This corresponds to a strike extent of 3.75 km, a width of 1.35 km, and an approximate elevation range of 800 m.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Lithologies

Mineralization is hosted within a broad assemblage of mafic volcanic rocks with an overall east-west trend.  Detour Gold had drill tested this mineralized corridor for a distance of over 5 km, west from the former Campbell pit.  The bulk of the mineralization within this corridor is concentrated along a highly-strained corridor of a moderate to strong potassic alteration envelope at the contacts between pillowed and massive mafic flows.

At the eastern end of this corridor at the Detour Lake Mine is the Main Zone.  The Main Zone was the largest gold-bearing mineralized zone and consisted of gold mineralization occurring in the chert marker horizon or in quartz and quartz-carbonate vein systems splaying from the Sunday Lake Deformation Zone.  Historic quartz zones Q50, Q70, Q100, and Q120 zones were typical quartz veins arrays splaying off the Sunday Lake Deformation Zone into the hanging wall. 

The former Campbell open pit is located at the shallowest zone developed along the contact between massive Mg-rich tholeiitic and pillowed Fe-rich tholeiitic volcanic rocks. 

West of section 19,620E, the mineralization mainly straddles the lower massive flow-pillow flow contact and is commonly associated with increased biotite alteration.  Mineralization is generally well distributed within this sequence but lithological changes to coarser and massive facies may locally affect mineralization continuity.

From sections 16,160E to 17,160E, Placer Dome intersected the QK Zone along a massive flow-pillow flow contact between 600-750 m below surface. 

A geology plan is included as Figure 7-4, and geological cross-sections in Figure 7-5 to Figure 7-7.

The Main Zone mineralization, the focus of historical underground mining, strikes easterly to northeasterly, has an average dip of 70⁰N.  It has a plunge of 40⁰W near surface, flattening out to 0º below the 660 m level.  The hanging wall contact is irregular, resulting from diverging quartz vein structures.  The footwall contact is more regular and undulates with local dips varying from 30⁰ to near vertical.  The Quartz Hangingwall Zones strike at azimuth 080⁰ with a vertical to near vertical dip, and a plunge of 45⁰_W parallel to the Main Zone.

The Main Zone extends to a depth of 745 m, is open to the west along strike, and dips north at an average of 70⁰.  The Quartz Hangingwall Zones, also the subject of historical underground mining, are characterized by discrete groups of steeply- dipping (predominately north) quartz veins. Generally having widths of 3-5 m, these quartz zones appear to splay off the chert marker horizon, although it is difficult to trace these zones directly back to the chert.  Potassic alteration is locally associated with these zones.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-4: Deposit Geology Plan

Note:  Figure prepared by Kirkland Lake Gold, 2020.  In this figure, green = pillowed volcanic rocks; blue = ultramafic intrusive rocks; magenta = talc; khaki = volcaniclastic rocks and tan = granodiorite.  Red shapes are the outlines of the mineralized envelopes.

Figure 7-5: Geological Section, Detour Lake, 589690 E (looking east)

Note:  Figure prepared by Kirkland Lake Gold, 2020. In this figure, green = pillowed volcanic rocks; purple = ultramafic intrusive rocks; magenta = talc.  Red shapes are the outlines of the mineralized envelopes.  Blue lines are drill traces.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-6: Geological Section, Detour Lake, 590,740 E (looking east)

Note:  Figure prepared by Kirkland Lake Gold, 2020.  In this figure, green = pillowed volcanic rocks; magenta = talc.  Red shapes are the outlines of the mineralized envelopes.  Drill traces in blue. 

Figure 7-7: Geological Section, Detour Lake, 591,640 E (looking east)

Note:  Figure prepared by Kirkland Lake Gold, 2020. In this figure, green = pillowed volcanic rocks; magenta = talc; thick black line = chert marker horizon; pale yellow = volcaniclastic rocks.  Red shapes are the outlines of the mineralized envelopes.  Drill traces in blue.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The mineralization hosted in the Main and Quartz Hangingwall Zones was tested by underground core drilling to a vertical depth of 900 m from surface and approximately 100 m below historical mine workings.  The results from this drilling demonstrate that there may be potential to extend this mineralization at depth.

The footwall Talc Zone is principally located between sections 19,700E and 20,540E (eastern end of the Detour Lake Mine).  It is hosted in highly altered (i.e., serpentinized and talcose) ultramafic flows with mineralization concentrated at both the upper contact (chert marker horizon), and lower contact of the Sunday Lake Deformation Zone, next to barren volcaniclastics and mafic volcanic rocks.  Locally, the mineralization is cut by felsic to intermediate intrusive dykes, ranging in width from 0.3-25 m.  The footwall mineralization commonly contains boudins of quartz veins and felsic as well as intermediate dyke slivers.  It is generally intensely sheared, especially in the area adjacent to the contact with the volcaniclastic sediments.

Mineralization

Gold is associated with quartz-carbonate-pyrite-pyrrhotite ± tourmaline veins and/or disseminated to very local semi-massive sulphides in hydrothermally-altered wall rocks.

There are two main mineralized zones, defined as hanging wall mineralization and footwall mineralization.  Figure 7-8 is a plan view example showing the distribution of the two mineralized zones.  Figure 7-9 is a section view example.

Hanging Wall

The hanging wall gold mineralization occurs in several different rock units within broad sub-vertical mineralized envelopes and splits into several sub-vertical domains sub-parallel to the orientation of the Sunday Lake Deformation Zone. 

The Main Zone was the largest gold-bearing mineralized zone exploited in the period 1983-1987 and consists of gold mineralization occurring in the chert marker horizon or in quartz and quartz-carbonate vein systems splaying from the Sunday Lake Deformation Zone.

In the Campbell pit area, <1 m thick quartz veins, with a frequency of greater than one vein per metre, were part of a series of sub-vertically dipping east-west-trending highly-strained zones.  Gold generally occurred as free gold with these veins. 

West of section 19,620E, mineralization is commonly associated with increased biotite alteration, shearing, narrow quartz veining and minor pyrite or pyrrhotite.  Local zones of strong brecciation with sulphide infilling have also been recognized along with minor chalcopyrite, telluride minerals and visible gold.  Gold mineralization is associated with a series of sub-vertical to arcuate deformation zones characterized by enhanced strained fabrics, well defined open-space breccias, and to a lesser degree sheeted shear-hosted veins and extensional veins. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-8: Plan of Footwall and Hanging Wall Mineralization (60 m elevation)

Note:  Figure prepared by Kirkland Lake Gold, 2020.

Figure 7-9: Footwall and Hangingwall Mineralization Section 592040E (looking east)

Note:  Figure prepared by Kirkland Lake Gold, 2020.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

The QK Zone further to the west is open down plunge and has not been tested below 800 m.  This mineralization is associated with narrow parallel to sub-parallel quartz veins, quartz boudins and sulphide rich veins/breccias with adjacent silicification and potassic alteration envelopes. 

Footwall Mineralization

The Talc Zone varies in width from 4-15 m and tends to be less continuous along strike.  Gold in the Talc Zone is dominantly associated with pyrite, pyrrhotite, and minor chalcopyrite along foliation planes, narrow discrete shears or strain zones, and in irregular lenses.  The zones also contain short deformed lenses or boudinaged quartz veins.  In some cases, it appears that the mineralization is controlled by strong fault structures containing several centimetres of gouge material.

7.3.2 West Detour and North Pit Areas

Dimensions

The West Detour mineralization extends from mine grid sections 14,500E to 17,600E and 19,100N to 21,300N and between elevation 5,300 and 6,300 m.  This corresponds to a strike extent of 3.1 km, a width of 2.2 km, and an approximate elevation range of 1 km.

Lithologies

Generally, the gold zones occur in a variety of structural settings and several rock types including massive to pillowed tholeiitic basalt flows, variably deformed-altered basaltic to peridotitic komatiite units, cherty tuffs, gabbro and deformed felsic to intermediate dykes. Larger gold zones are subparallel to concordant with stratigraphy (contact related) and smaller quartz and potassic veins occur along splays.

Most of the West Detour mineralization is closely associated with talc/chlorite greenstone schist within an auriferous structural corridor referred to as the M Zone.  The QK Zone extends from 16,160E to 17,160E between 600-750 m below surface.

Approximately 200 m north of the M Zone, the North Walter Lake Zone is developed in a zone of high strain with deformed quartz veins within pillowed to massive mafic volcanic flows.  The North Walter Lake Zone gold mineralization is very similar to that found in the Detour Lake Mine hanging wall sequence.  It is hosted by a komatiitic tholeiite mafic volcanic unit and flanked by Fe-tholeiitic mafic rocks in the hanging wall and Mg-tholeiitic mafic rocks in the footwall.

Mineralization

The M Zone lies approximately 400-500 m north of the chert maker horizon and is a westerly-trending gold system that is spatially associated with the margins of the chlorite schist unit.  The chlorite schist stratigraphic horizon and associated gold mineralization was traced by drilling for approximately 5 km.  The footwall and hanging wall sequence of the chlorite schist in the M Zone is variably biotite altered with fairly abundant fractures and well-defined foliation (local veining) with associated pyrite, pyrrhotite, and rarely chalcopyrite.  The mineralized zones appear lensoidal and plunge 20° west.  Mineralized lenses vary from 5-50 m in true width.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Mineralization hosted in the QK zone is associated with narrow veins that are parallel to sub-parallel to stratigraphy, quartz boudins, and sulphide-rich veins/breccias within silicified and potassic alteration envelopes up to 25 m in true width.

Gold mineralization in the North Walter Lake Zone is within a relatively weak quartz vein stockwork with a low pyrite and pyrrhotite sulphide content.  Mineralization is associated with moderate to strong shearing, potassic alteration of the mafic volcanic units, narrow quartz veining and minor pyrite and pyrrhotite.

An example cross-section showing the geology and mineralized zones at West Detour is included as Figure 7-10.

7.3.3 Zone 58N

Dimensions

The Zone 58N mineralized system has been intersected over an east-west strike length of 450 m, from surface to a depth of 800 m, and the mineralized system remains open at depth. The mineralization extends from approximately 595,300E to 595,750E and 5,533,700N to 5,533,800N (UTM coordinates).  The width of the mineralization is variable, ranging from 4 m to >100 m at the centre of the deposit.  Infill drilling has demonstrated that the geology and mineralization dip subvertically at 75º to the south.

Lithologies

Gold mineralization in Zone 58N is within the southern portion of a feldspar porphyry intrusion, and characterized by intense brittle deformation and stockworks of quartz ± carbonate ± tourmaline veins with strong biotite-sericite-silica alteration.  The thickness of the feldspar porphyry host rock can be >100 m and on average, mineralized lenses are 30 m wide. The feldspar porphyry intrusion narrows to the east and west near surface.  Gold mineralization within Zone 58N is hosted by a swarm of plagioclase-phyric tonalitic dykes that intrude mafic rocks of the Deloro assemblage.

The geometry of host dykes is controlled by a large (~1,000 m in diameter) cylindrically-shaped intermediate equigranular intrusion, resulting in emplacement at a slightly oblique angle to the strike of regional stratigraphy. The dyke rocks, and associated mineralization, reach a maximum width of 150 m near the southwestern portion of the intermediate intrusion, and taper along strike.

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-10: Geological Section, West Detour, 16,340 E (looking west)

Note:  Figure prepared by Detour Gold, 2018.

Mineralization

Visible gold is often present and occurs within coarse pyrite or as free gold within quartz.  Sulphide mineralization associated with gold ranges from 0.5-5% pyrite with minor chalcopyrite, bismuth-tellurides, molybdenite and scheelite.  Gold is found within and at the margins of quartz ± tourmaline ± carbonate stockwork-type veins that infill areas of brittle deformation.  Visible gold occurs in nearly every drill hole that intersects mineralization and is also present as micro-inclusions within pyrite grains, or intergrown with bismuth-tellurides.

A simplified cross-section showing the mineralized zones is provided as Figure 7-11. 

Detour Lake Operations Ontario, Canada NI 43-101 Technical Report

Figure 7-11: Cross Section, Zone 58N, Zone 75, 595505 E (looking west)

Note:  Figure prepared by Detour Gold, 2018.

7.3.4 Zone 75

The surface expression of Zone 75 is located 20-50 m south of Zone 58N.

Dimensions

The Zone 75 mineralized system has been intersected over an east-west strike length of approximately 650 m, from surface to a depth of 600 m, and the mineralized system remains open at depth.  The mineralization extends from approximately 595,200E to 595,775E and 5,533,700N to 5,533,775N (UTM coordinates).  Mineralized intervals in the 75 Zone are 1-5 m wide and up to 9 m locally.