Bornite

Bornite is a high-grade copper deposit with significant exploration potential, located in a safe, mining-friendly jurisdiction.

The Bornite deposit (“Bornite”) is a carbonate hosted copper-cobalt deposit located near Kobuk, Alaska, and is approximately 25 kilometers southwest of the Company’s Arctic Project.

Key Facts
Location	Alaska, USA
Deposit Type	Carbonate-Hosted Copper-Cobalt
Host	Bornite Carbonate Sequence
Age	Lower Devonian to Upper Silurian
Main Economic Elements	Copper

The project has the potential to further enhance the long-term economics of the Ambler mining district. Trilogy Metals announced the results of the Bornite Preliminary Economic Assessment (“PEA”) on January 15, 2025.

The Bornite PEA describes the technical and economic viability of establishing an underground mining operation for a 6,000 tonne-per-day operation with a 17-year mine life. The PEA assumes re-purposing the infrastructure described in Trilogy’s 2023 Feasibility Study for the Arctic Project for use with the Bornite Project once the Arctic deposit has been depleted. The PEA was prepared on a 100% ownership basis and all amounts are in US dollars.

2025 PEA

1.9 billion pounds of copper over 17-year mine life.
Potential to extend mine activity for the Upper Kobuk Mineral Projects to over 30 years.
Pre-tax Net Present Value (“NPV”)_8% of $552.1 million and an Internal Rate of Return (“IRR”) of 23.6%.
After-tax NPV_8% of $393.9 million and after-tax IRR of 20.0%.

Metal Production and Assumed Metal Prices

Annual Payable Metals Production
Copper (‘000 lb)	109,061
Metal Price
Copper ($/lb)	4.20

Operating and Capital Costs

Operating Costs
Underground Mining ($/t milled)	37.74
OTR Haulage ($/t milled)	5.35
Processing ($/t milled)	24.82
AAP Road ($/t milled)	14.33
G&A ($/t milled)	13.42
Water Management ($/t milled)	2.87
Surface Operations Cost ($/t milled)	0.44
Total Operating Cost ($/t milled)	98.97

Notes:

G&A = general & administrative
Figures may not sum due to rounding

Capital Expenditures
Initial Capital ($ million)	503.4
Sustaining Capital ($ million)	363.1
Total Capex ($ million)	866.5
Mine Closure & Reclamation ($ million)	81.2

Financial Results

Financial Summary
Pre-tax Cash Flow ($ million)	1,582.5
After-tax Cash Flow ($ million)	1,218.8
Pre-tax NPV8% ($ million)	552.1
After-tax NPV8% ($ million)	393.9
Cash Cost ($/lb Cu payable)	2.76
All-in Cost ($/lb Cu payable)	3.35
Pre-tax IRR (%)	23.6
Pre-tax Payback Period (years)	4.0
Post-tax IRR (%)	20.0
Post-tax Payback Period (years)	4.4

Geology and Mineralization

Mineralization is hosted within the Devonian aged Bornite carbonate sequence.
Widespread hydrothermal dolomitization is a characteristic of the belt and locally hosts the associated copper and cobalt mineralization.
Bornite has characteristics similar to a series of districts and deposits including the Mount Isa district in Australia, the Tynagh deposit in Ireland, the Kipushi deposit in the DRC and the Tsumeb deposit in Namibia.
All of these deposits show early epigenetic characteristics; emplacement in carbonate stratigraphy; and early pyrite-dolomite alteration followed by copper-dominant sulphide mineralization.
Copper mineralization at Bornite is comprised of chalcopyrite, bornite, and chalcocite as stringers, veinlets, and breccia fillings distributed in stacked, stratabound zones exploiting favourable stratigraphy. Stringer and massive pyrite and locally significant sphalerite occur above and around the copper zones, while locally massive pyrite and sparse pyrrhotite occur in association with siderite alteration below and adjacent to copper mineralization.
Cobalt mineralization at Bornite is composed of cobaltiferous pyrite within and enveloping the copper mineralized zones and cobalt sulphides including carrollite and cobaltite directly associated with copper bearing minerals.
Mineralization occurs, in order of increasing grade, as disseminations, irregular and discontinuous stringer-style veining, breccia matrix replacement, and stratiform massive sulphides.
From 1957 to 2019, a total of 273 holes targeted the Bornite deposit during 24 different campaigns. 222 surface core holes and 51 underground core holes were drilled, totalling 106,406 meters.

Download NI 43-101 Technical Report Download

Download SK-1300 Technical Report Download

Resource Estimate for Bornite Project

Class	Type/Area	Cut-off Cu (%)	Tonnes (Mt)	Average Grade Cu (%)	Contained Metal Cu (Mlb)
Inferred	In-Pit	0.50	170.4	1.15	4,303
	Outside-Pit South Reef	1.45	27.5	2.78	1,687
	Outside-Pit Ruby Zone	1.79	10.4	2.28	521
	Underground Development	0.70	0.7	0.98	16
Total Inferred – 100%			208.9	1.42	6,527
Total Inferred – 50% Attributable Interest			104.45	1.42	3263.50

1. Mineral Reources were reported in the S-K 1300 Bornite Report effective as of November 30, 2024 and the NI 43-101 Bornite Report with an effective date of November 30, 2024. A Qualified Person and an employee of Trilogy Metals has approved the mineral resources included in this Annual Report on Form 10-K as of November 30, 2025 and reviewed the resources and material assumptions in the S-K 1300 Bornite Report and confirmed that the resources and material assumptions remain current as of November 30, 2025.
2. Mineral Resources in the S-K 1300 Bornite Report were prepared in accordance with the standards and definitions of S-K 1300. Mineral Resources in the NI 43-101 Bornite Report were prepared in accordance with the CIM Mineral Resources and Mineral Reserves Definitions Standards. Mineral resources are exclusive of mineral reserves. There have been no mineral reserves estimated on the Bornite Property.
3. The assessment is preliminary in nature, it includes Inferred mineral resources that are considered too speculative geologically to have modifying factors applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that this economic assessment will be realized.
4. Mineral resources are reported in place (point of reference).
5. Mineral resources are constrained by: an open pit shell at a cut-off grade of 0.50% Cu, with an average pit slope of 43 degrees; and underground mining shapes assuming cut-and-fill mining method based on a 1.79% Cu grade shell for Ruby Zone and an optimized underground mineable stope shape assuming sublevel stoping mine method based on a break-even cut-off grade of 1.45% for South Reef. The cut-off grades assume a $4.60/lb Cu price over the expected 17-year LOM, process recovery of 90.47%, process cost of $21.00/t processed, treatment, refining, sales cost of $0.78/lb Cu in concentrate, road use cost of $8.04/t processed, and 2% NSR royalty. For the open pit, costs include mining costs of $3.34/t mined and G&A cost of $4.30/t processed. For mining at South Reef, costs include mining costs of $65.00/t mined and G&A cost of $14.50/t processed. For mining at Ruby Zone, costs include mining costs of $90.00/t mined and G&A cost of $14.50/t processed. The long-term metal price forecast used a combination of information derived from 22 financial institutions, from pricing used in technical reports filed with Canadian regulatory authorities over the previous 12-month period from the effective date of the mineral resource estimate, from pricing reported by major mining companies in public filings such as annual reports, historical average pricing.
6. Underground development material uses a marginal cut-off of 0.70% Cu where the mining costs are excluded.
7. Figures may not sum due to rounding.
8. The Mineral Resource estimates are shown on 100% and 50% basis. Trilogy’s attributable interest is 50%.

The South Reef includes a relatively high-grade mineralized zone that is amenable to underground mining methods. The table below illustrates the portions of the South Reef at a higher cut-off grade (sensitivity to cut-off grade), representing an opportunity that could be considered for mining of this material using only underground mining methods which is illustrated in the PEA.

Portions Of South Reef Mineral Resource Amenable To Underground Mining

Class	Type/Area	Cut-off Cu (%)	Tonnes (Mt)	Average Grade Cu (%)	Contained Metal Cu (Mlb)
Inferred	In-Pit South Reef¹	1.45	14.2	2.80	876
Inferred	Outside-Pit South Reef²	1.45	27.5	2.78	1,687
Total Inferred (South Reef)			41.7	2.79	2,563

Notes:

The 1.45% Cu break-even cut-off assumes sublevel stoping mine method. The cut-off grades assume a $4.60/lb Cu price, process recovery of 90.47%, process cost of $21.00/t processed, mining costs of $65.00/t mined and G&A cost of $14.50/t processed, treatment, refining, sales cost of $0.78/lb Cu in concentrate, road use cost of $8.04/t processed, and 2% NSR royalty.
Subset of the mineral resource using a higher cut-off to what was used in table above and is not additive to the in-pit mineral resource reported in table above.
Restatement of the mineral resources outside of the pit and is not additive to the mineral resource.

Subset of the Mineral Resources Included in the Underground Life-of-Mine Plan

Class	Tonnes (Mt)	Average Grade Cu (%)	Contained Metal Cu (Mlb)
Total Inferred	36.9	2.61	2,125

1. Mineral resources within the mine plan were estimated using sublevel stoping underground mining method and includes variable dilution and a mining recovery of 95%.
2. Mineral resources are not mineral reserves and do not have demonstrated economic viability.
3. Input assumptions used to determine mineable stope shapes include a Cu price of $4.20/lb, mine operating cost of $73.29/t, process operating cost of $19.84/t, G&A and surface costs of $9.64/t, haulage and road use costs of $28,78/t, closure and water treatment costs of $1.26/t, shipping, treatment, refining and selling costs of $0.78/lb Cu, process recovery of 90%, and NSR royalty of 2%.
4. Production stope cut-off of 1.6% Cu and development cut-off of 0.7% Cu. The production stope cut-off input assumptions include a copper price of $4.20/lb, mine operating cost of $44.08/t, process operating cost of $24.82/t, G&A and surface cost of $17.3/t, and sustaining costs of $8.52/t, road use costs of $14.4/t, shipping, treatment, refining and selling costs of $0.78/lb Cu, process recovery of 90.89%, and average NSR royalty of 2.25%.