Exhibit 99.1

NI 43-101 Technical Report

Prefeasibility Study for the Soto Norte

Project, Santander, Colombia

 

 

Prepared by:

Kate Kitchen, MAIG

Peter Lock, FAusIMM

Jan Eklund, P.Eng.

Nicholas Sianta, P.E.

Rolf Schmitt, P.Geo.

Prepared for:

Aris Mining Corporation

1021 West Hastings Street

Suite 2400

Vancouver BC V6E 0C3

Canada

Effective Date: August 18, 2025

Report Date: September 3, 2025

NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

Forward looking information

This technical report may contain or incorporate by reference information that constitutes “forward-looking information” or “forward-looking statements” (collectively, forward-looking information) within the meaning of the applicable securities legislation. All statements, other than statements of historical fact, contained or incorporated by reference in this technical report including, but not limited to, statements related to those items listed below, constitute forward-looking information. Forward-looking information involves known and unknown risks, uncertainties, and other factors that may cause the actual results, performance or achievements of Aris Mining to be materially different from the forward-looking information contained herein. When used in this technical report, such information uses words such as “aims”, “anticipates”, “assumes”, “believes”, “budget”, “committed”, “continue”, “plans”, “project”, “endeavors”, “ensures”, “estimates”, “expects”, “focus”, “forecasts”, “forward”, “guidance”, “intends”, “likely”, “opportunity”, “outlook”, “pending”, “possible”, “potentially”, “predicts”, “proposed”, “scheduled”, “seeks”, “strives”, “targets” or variations of such words and phrases or statements that certain actions, events or results “can”, “could”, “generally”, “may”, “might”, “should”, “will” or “would” occur or be achieved and any other similar terminology.

The forward-looking information contained herein reflects current expectations regarding future events and operating performance and speaks only as of the date of this technical report. Generally, forward-looking information involves significant risks and uncertainties; therefore, it should not be read as a guarantee of future performance or results and will not necessarily be an accurate indication of whether or not such results will be achieved. Undue reliance should not be placed on such statements. A number of factors could cause the actual results to differ materially from the results discussed in the forward-looking information. Although the forward-looking information is based on what management of Aris Mining believes are reasonable assumptions, Aris Mining cannot assure readers that actual results will be consistent with the forward-looking information.

This technical report includes forward-looking information pertaining to, among other factors, the following: the projections, assumptions and estimates related to the Project, including, without limitation, those relating to development, capital and operating costs, production, grade, recoveries, metal prices, life of mine, mine sequencing, economic assumptions such as capital expenditures, cash flow and revenue, mine design, permitting and licensing, mining techniques and processes, timing of estimated production, equipment, staffing, emissions, use of land, estimates of mineral resources, use of energy storage technologies, the timing and expectations for other future studies, the operation of Aris Mining, the development and future operation of the Project, and the ability to secure state and local permits for the Soto Norte Project. 

Forward-looking information is based upon a number of estimates and assumptions that, while considered reasonable by Aris Mining as of the date of such statements, are inherently subject to significant business, economic and competitive uncertainties and contingencies. With respect to forward-looking information contained herein, the assumptions made by Aris Mining include but are not limited to:

 

•

the environmental liabilities to which Project is subject;

•

political developments in any jurisdiction in which Aris Mining operates being consistent with Aris Mining’s current expectations;

•

the validity of its existing title to property and mineral claims;

•

Aris Mining’s ability to maintain surface rights and legal access to property and mineral claims;

•

experts retained by Aris Mining, technical and otherwise, being appropriately reputable and qualified;

•

the viability, economically and otherwise, of developing the Project;

•

Aris Mining’s ability to obtain qualified staff and equipment in a timely and cost-efficient manner to meet Aris Mining’s demand; and

•

the impact of acquisitions, dispositions, suspensions or delays on Aris Mining’s business.

Forward-looking information is based on current expectations, estimates and projections that involve a number of risks which could cause the actual results to vary and, in some instances, to differ materially from those described in the forward- looking information contained in this technical report. These material risks include, but are not limited to:

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

•

local environmental and regulatory requirements and delays in obtaining required environmental and other licenses, including delays associated with local communities and indigenous peoples;

•

changes in national and local government legislation, taxation, controls, regulations and political or economic developments in Canada or Colombia, including with respect to the TRA and Order 044;

•

uncertainties and hazards associated with gold exploration, development and mining, including but not limited to, environmental hazards, industrial accidents, unusual or unexpected formations, pressures, cave-ins, flooding, polymetallic concentrate losses, and blockades and operational stoppages;

•

risks associated with costs, supply chain disruptions, and financial risks due to changes in tariffs, trade policies, international trade disputes, or regulatory shifts;

•

economic and political risks associated with operating in foreign jurisdictions, including emerging country risks, exchange controls, expropriation risks, political instability and corruption;

•

risks associated with capital and operating cost estimates;

•

dependence of operations on construction and maintenance of adequate infrastructure;

•

fluctuations in foreign exchange or interest rates and stock market volatility;

•

operational and technical problems;

•

Aris Mining’s ability to maintain good relations with employees and contract mining partners;

•

reliance on key personnel;

•

competition for, among other things, capital, and the acquisition of mining properties and undeveloped lands;

•

uncertainties relating to title to property and mineral resource and mineral reserve estimates;

•

risks associated with acquisitions and integration;

•

risks associated with Aris Mining’s ability to meet its financial obligations as they fall due;

•

volatility in the price of salable metal or certain other commodities relevant to Aris Mining’s operations, such as diesel fuel and electricity;

•

risks that Aris Mining’s actual production may be less than is currently estimated;

•

risks associated with servicing Aris Mining’s indebtedness and additional funding requirements for exploration, operational programs or expansion properties, as well as to complete any large scale development projects;

•

risks associated with general economic factors, including ongoing economic conditions, investor sentiment, market accessibility and market perception;

•

changes in the accessibility and availability of insurance for mining operations and property;

•

environmental, sustainability and governance practices and performance;

•

risks associated with climate change;

•

risks associated with the reliance on experts outside of Canada;

•

costs associated with the decommissioning of Aris Mining’s mines and exploration properties;

•

potential conflicts of interest among the directors of Aris Mining;

•

uncertainties relating to the enforcement of civil labilities and service of process outside of Canada;

•

risks associated with keeping adequate cyber-security measures;

•

risks associated with operating a joint venture; and

•

other factors further discussed in the section entitled “Risk Factors” in Aris Mining’s Annual Information Form for the year ended December 31, 2024 which is available on Aris Mining’s website at www.aris-mining.com, on SEDAR+ at www.sedarplus.ca and included as part of Aris Mining’s Annual Report on Form 40-F, filed with the SEC at www.sec.gov.

Readers are cautioned that the foregoing lists of factors are not exhaustive. There can be no assurance that forward-looking information will prove to be accurate. Forward-looking information is provided for the purpose of providing information about management’s expectations and plans relating to the future. The forward-looking information included in this technical report is qualified by these cautionary statements and those made in Aris Mining’s other filings with the securities regulators of Canada including, but not limited to, the cautionary statements made in the “Risks and Uncertainties” section of Aris Mining’s Management’s Discussion and Analysis for the three and six months ended June 30, 2025 which is available on Aris Mining’s website at www.aris-mining.com, on SEDAR+ at www.sedarplus.ca and on Aris Mining’s profile with the SEC at www.sec.gov.

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

The forward-looking information contained herein is made as of the date of this technical report and Aris Mining assumes no obligations to update or revise it to reflect new events or circumstances, other than as required by applicable securities laws.

Non-GAAP financial measures

This technical report refers to a number of non-GAAP financial measures, which are not measures recognized under International Financial Reporting Standards (IFRS) and do not have a standardized meaning prescribed by IFRS. These non-GAA financial measures described below do not have standardized meanings under IFRS, may differ from those used by other issuers, and may not be comparable to similar financial measures reported by other issuers. Accordingly, these 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.

Cash costs – Cash cost and cash cost per ounce ($ per oz) are a common financial performance measure and ratio in the mining industry; however, they have no standard meaning under IFRS. Cash cost $ per oz is calculated by dividing total cash costs by volume of gold ounces projected to be produced on a payable basis.

All-in sustaining costs (AISC) – AISC and AISC $ per oz sold are a common financial performance measure and ratio in the mining industry; however, they have no standard meaning under IFRS. AISC is calculated by dividing AISC by volume of gold ounces projected to be produced on a payable basis.

Earnings before interest, taxes, depreciation and amortization (EBITDA) – EBITDA is a common financial performance measure in the mining industry; however, it has no standard meaning under IFRS. EBITDA represents earnings before interest, income taxes and depreciation, depletion and amortization.

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

Contents

 

Figures and tables			14
1 Summary			16
1.1 Introduction			16
1.2 Property description, location, and access			18
1.2.1 Location and access			18
1.2.2 Mineral tenure, Aris Mining’s interest, surface rights, and obligations			18
1.2.3 Royalties, agreements, and encumbrances			18
1.2.4 Significant factors and risks			18
1.3 History			19
1.4 Geological setting, mineralization, and deposit types			20
1.4.1 Regional, local, and property geology			20
1.4.2 Mineralization			20
1.4.3 Deposit types			21
1.5 Exploration			21
1.6 Drilling			22
1.7 Sampling, analysis, and data verification			22
1.7.1 Sample preparation			22
1.7.2 Quality assurance and quality control			22
1.7.3 Security measures			23
1.7.4 Analytical procedures			23
1.7.5 Data verification			23
1.8 Mineral processing and metallurgical testing			24
1.8.1 Testwork history			24
1.8.2 Mineralogical testwork			25
1.8.3 Comminution testwork			25
1.8.4 Gravity separation and flotation testwork			25
1.8.5 Deleterious elements			26
1.8.6 Metallurgical recovery			26
1.9 Mineral resource and mineral reserve estimates			26

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

1.9.1 Mineral resource estimate			26
1.9.2 Mineral reserve estimate			27
1.10 Mining operations			27
1.11 Processing and recovery operations			28
1.12 Infrastructure, permitting, and compliance activities			29
1.12.1 Mine infrastructure			29
1.12.2 Rope conveyor system			29
1.12.3 Process support facilities			29
1.12.4 Filtered tailings storage facilities			30
1.12.5 Water sources and management			31
1.12.6 Power			32
1.12.7 Environmental factors			32
1.12.8 Permitting factors			33
1.12.9 Social or community factors			34
1.13 Capital and operating costs			36
1.13.1 Capital cost estimates			36
1.13.2 Operating cost estimates			37
1.14 Economic analysis			38
1.15 Exploration, development, and production			41
1.16 Conclusions			41
1.17 Recommendations			41
2 Introduction			44
2.1 Issuer and purpose of the technical report			44
2.2 Source information			44
2.3 Qualified persons and personal inspections			44
2.4 Currencies, units, and coordinate system			45
3 Reliance on other experts			46
4 Property description and location			47
4.1 Property location			47
4.2 Mineral tenure and Aris Mining’s interest			47
4.3 Surface rights and legal access			50

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

4.4 Royalties, agreements, and encumbrances			50
4.5 Environmental liabilities			51
4.6 Permits			51
4.7 Significant factors and risks			52
5 Accessibility, climate, local resources, infrastructure, and physiography			53
5.1 Property access, transport, population centres, and mining personnel			53
5.2 Topography, elevation, vegetation, and climate			54
5.3 Surface rights and surface area			54
5.4 Power and water			54
6 History			56
6.1 Early history and historical production			56
6.2 Ownership history			56
6.3 Exploration and development work			56
6.3.1 Ventana			56
6.3.2 AUX Colombia			56
6.3.3 Minesa and Aris Mining			57
6.4 Historical mineral resource and mineral reserve estimates			57
7 Geological setting and mineralization			58
7.1 Regional geology			58
7.2 Local geology			59
7.3 Property geology			60
7.4 Mineralization and alteration			61
8 Deposit types			62
9 Exploration			63
9.1 2006 to 2011 Ventana			63
9.2 2011 to 2013 AUX Colombia			63
9.3 2015 to 2018 Minesa			63
9.4 Recommendations			63
10 Drilling			65
10.1 Drilling summary			65
10.2 Drilling methods			65

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

10.2.1 Drillhole collar and downhole surveys			66
10.3 Drilling, sampling, and recovery factors			66
11 Sample preparation, analysis, and security			67
11.1 Introduction			67
11.2 Channel sampling and security			67
11.2.1 Ventana			67
11.2.2 AUX Colombia			67
11.2.3 Minesa			67
11.3 Soil sampling and security			67
11.3.1 Ventana			67
11.3.2 AUX Colombia			67
11.3.3 Minesa			67
11.4 Drillhole sampling, QAQC, and security			68
11.4.1 Overview			68
11.4.2 Ventana			68
11.4.3 AUX Colombia			69
11.4.4 Minesa			69
11.5 Laboratory sample preparation and analytical methods			69
11.5.1 Ventana			69
11.5.2 AUX Colombia			70
11.5.3 Minesa			70
11.6 Bulk density measurements			70
11.7 Adequacy of the sample preparation, security, and analytical procedures			70
12 Data verification			72
12.1 Geology data reviews			72
12.2 Mine engineering data reviews			72
12.3 Metallurgy and processing data reviews			73
12.4 Filtered tailings storage facility data reviews			73
13 Mineral processing and metallurgical testing			74
13.1 Introduction			74
13.2 Samples			74

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

13.3 Mineralogy and characterization			76
13.4 Comminution			77
13.5 Gravity separation and flotation			78
13.6 Thickening and filtration			80
13.7 Deleterious elements			80
13.8 Environmental characterization			80
13.9 Conclusions and recommendations			81
14 Mineral resource estimates			83
14.1 Disclosure			83
14.2 Available data			83
14.3 Geological interpretation			83
14.4 Statistics, sample compositing, and treatment of extreme grades			83
14.5 Block model construction and depletion for mining			84
14.6 Composite search and interpolation parameters			84
14.7 Estimation validation			84
14.8 Mineral resource classification			87
14.9 Cut-off grade and mineral resource constraint			87
14.10 Mineral resource tabulation			87
14.11 Mineral resource sensitivity to cut-off grade			88
14.12 Recommendations			89
15 Mineral reserve estimates			90
15.1 Disclosure			90
15.2 Method			90
15.2.1 Cut-off grade			90
15.2.2 Stope optimization			90
15.3 Mineral reserve tabulation			91
16 Mining methods			92
16.1 Introduction			92
16.2 Mine access and general layout			92
16.3 Underground infrastructure			93
16.4 Material handling			93

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

16.5 Hydrology and hydrogeology			94
16.5.1 Introduction			94
16.5.2 Hydrology			94
16.5.3 Hydrogeology			94
16.6 Mine water management			95
16.7 Mine ventilation			95
16.8 Mine geotechnical parameters			96
16.9 Mining method			97
16.10 Backfill			98
16.11 Mine planning and schedule			99
16.12 Mine equipment			101
16.13 Mine personnel			103
16.14 Recommendations			105
17 Recovery methods			106
17.1 Introduction			106
17.2 Process description			107
17.2.1 Feed preparation and transfer to surface			107
17.2.2 Grinding and gravity concentration			107
17.2.3 Sequential copper and pyrite flotation and regrind			107
17.2.4 Concentrate dewatering			108
17.2.5 Thickened tailings dewatering and storage			108
17.3 Reagents and consumables			109
17.4 Power, water, and air			109
17.5 Conclusions			110
18 Project infrastructure			112
18.1 Introduction			112
18.2 Surface mine infrastructure			112
18.3 Rope conveyor system			113
18.3.1 Introduction			113
18.3.2 Capacity			114
18.3.3 Design			116

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

18.3.4 Operation			116
18.3.5 Closure			116
18.3.6 Conclusions			116
18.4 Process support facilities			116
18.5 Filtered tailings storage facilities			117
18.5.1 Site description			117
18.5.2 Site investigations and engineering analyses			118
18.5.3 Design			118
18.5.4 Water management			119
18.5.5 Tailings placement			120
18.5.6 Closure			120
18.5.7 Post closure monitoring			121
18.5.8 Recommendations			122
18.6 Stormwater management			123
18.6.1 Introduction			123
18.6.2 Stormwater management plan			123
18.6.3 Stormwater management infrastructure			123
18.6.4 Recommendations			123
18.7 Utilities			124
18.7.1 Water sources and water treatment facilities			124
18.7.2 Power			124
18.7.3 Fuel			125
18.8 Terracing			125
18.9 On site roads			125
18.10 Off site logistics			125
19 Market studies and contracts			127
19.1 Market studies			127
19.1.1 Indicative commercial terms for the copper concentrates			127
19.1.2 Indicative commercial terms for the pyrite concentrates			127
19.1.3 Indicative commercial terms for the gravity recovered gold concentrates			127
19.2 Contracts			128

 

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NI 43-101 Technical Report   Prefeasibility Study for the Soto Norte Project, Santander, Colombia

 

19.3 Review and confirmation by the qualified person			128
20 Environmental studies, permitting, and social or community impact			129
20.1 Environmental setting, studies, and issues			129
20.1.1 Environmental setting			129
20.1.2 Environmental studies			129
20.1.3 Environmental management approach			129
20.1.4 Historical environmental liabilities			130
20.2 Social setting and community requirements			130
20.2.1 Social setting			130
20.2.2 Community engagement			130
20.2.3 Community employment, diversity, and socioeconomic opportunities			131
20.2.4 Contract mining partners			131
20.2.5 Land acquisition and resettlement			132
20.3 Filtered tailings facility and waste rock management			132
20.4 Site monitoring			132
20.5 Water management			132
20.5.1 Groundwater management			133
20.5.2 Extractive wastewater management			133
20.5.3 Water supply management			134
20.6 Permitting requirements			134
20.7 Mine closure requirements			135
20.8 Recommendations			136
21 Capital and operating costs			137
21.1 Capital cost estimate methodology			137
21.1.1 Processing facilities and surface infrastructure capital costs			137
21.1.2 Underground mining infrastructure capital costs			138
21.1.3 Capital cost summary			138
21.2 Operating cost estimate			139
21.2.1 Estimate methodology for processing and rope conveyor operating costs			139
21.2.2 Estimate methodology for underground mining operating costs			140
21.2.3 Estimate methodology for G&A operating costs			140

 

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21.2.4 Operating cost summary			140
22 Economic analysis			143
22.1 Estimate methodology			143
22.2 Project schedule			143
22.3 Taxes and royalties			146
22.4 Marketing assumptions			146
22.5 Commodity prices and gross revenue			146
22.6 Economic analysis results			148
22.7 Sensitivity analysis			151
22.8 Conclusions			152
23 Adjacent properties			153
24 Other relevant data and information			154
25 Interpretation and conclusions			155
26 Recommendations			156
27 References			158
28 Date, signatures, and certificates of Qualified Persons			159

 

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Figures and tables

 

Table 1-1		Soto Norte mineral resources effective August 18, 2025			27
Table 1-2		Soto Norte mineral reserves effective August 18, 2025			27
Table 1-3		Estimated initial capital costs			36
Table 1-4		Estimated deferred and sustaining capital costs			37
Table 1-5		Estimated operating costs			37
Table 1-6		Estimated life of mine unit operating costs			38
Table 1-7		Total life of mine production			39
Table 1-8		Total life of mine concentrate production			39
Table 1-9		Soto Norte economic evaluation results			39
Table 1-10		Sensitivity of NPV to discount rate			40
Table 1-11		Sensitivity of key economic indicators to gold price			40
Table 2-1		Responsibilities of each qualified person			45
Table 4-1		Property mineral title summary			48
Table 10-1		Drilling summary			65
Table 14-1		Composite statistics			84
Table 14-2		Mineral resource cut-off grade			87
Table 14-3		Soto Norte mineral resources effective August 18, 2025			88
Table 15-1		Mineral reserve cut-off grade			90
Table 15-2		Soto Norte mineral reserves effective August 18, 2025			91
Table 16-1		Annual mine development schedule			101
Table 16-2		Annual mine production schedule			101
Table 16-3		Mine equipment fleet			101
Table 16-4		Annual mine equipment schedule			102
Table 16-5		Annual mine personnel requirements			103
Table 21-1		Estimated initial capital costs			138
Table 21-2		Estimated deferred and sustaining capital costs			139
Table 21-3		Estimated annual capital expenditure schedule			139
Table 21-4		Estimated capital expenditure per depreciation class			139
Table 21-5		Estimated operating costs			141
Table 21-6		Estimated life of mine unit operating costs			141
Table 21-7		Estimated annual life of mine operating cost schedule			142
Table 22-1		Total life of mine production			143
Table 22-2		Total life of mine concentrate production			144
Table 22-3		Annual mining and processing schedule			145
Table 22-4		Life of mine average concentrate marketing terms			146
Table 22-5		Annual payable metals, gold revenue, by-product credits, and treatment and refining
charges, penalties, and shipping costs					147

 

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Table 22-6		Economic evaluation results			148
Table 22-7		Sensitivity of NPV to discount rate			148
Table 22-8		Annual after tax cash flow schedule			149
Table 22-9		Sensitivity of key economic indicators to gold price			151
Table 22-10		Sensitivity of NPV5% to operating and capital costs and gold price			151
Figure 4-1		Property location map - source Aris Mining 2025			47
Figure 4-2		Property mineral title plan – source Aris Mining 2025			49
Figure 5-1		Property access map - source Google 2025			53
Figure 7-1		Map of the regional geology – adapted from the Colombian Geological Service 2025			58
Figure 7-2		Map of the local geology – source Aris Mining 2025			59
Figure 7-3		Plan of the Property mineralized vein systems – source Aris Mining 2025			60
Figure 7-4		Long section of the Property mineralized vein systems – source Aris Mining 2025			61
Figure 13-1		Long sections of metallurgical testwork sample locations – source Aris Mining, 2025			75
Figure 14-1		Cross sections of estimated and input composite gold grades – Source Aris Mining 2025			85
Figure 14-2		Mineral resource sensitivity to cut-off grade - Source Mining Plus 2025			88
Figure 16-1		Plan view of mine design - Source Aris Mining 2025			92
Figure 16-2		Long section of mine design - Source Aris Mining 2025			93
Figure 16-3		Long sections of stope widths – Source Aris Mining 2025			97
Figure 16-4		Long sections of stope gold grades – Source Aris Mining 2025			99
Figure 17-1		Soto Norte processing flow sheet – Source LogiProc 2025			106
Figure 18-1		Project infrastructure plan – Source Aris Mining 2025			112
Figure 18-2		Mine area surface infrastructure plan – Source Aris Mining 2025			113
Figure 18-3		Example of a rope conveyor system on similar terrain – source Doppelmayr 2025			114
Figure 18-4		Plan of the rope conveyor system route – source Aris Mining 2025			115
Figure 18-5		Long section of the rope conveyor system route – adapted from Doppelmayr 2025			115
Figure 18-6		Plan of process support facilities – Source Aris Mining 2025			117
Figure 18-7		Plan of filtered tailings storage facilities – Source Aris Mining 2025			119
Figure 22-1		Annual tonnes mined over the life of mine – Source Mining Plus 2025			144
Figure 22-2		Annual processed grade and gold produced in concentrates – Source Mining Plus 2025			144
Figure 22-3		Sensitivity of NPV5% to operating and capital costs and gold price – Source Mining Plus 2025			151

 

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1 Summary

1.1 Introduction

This technical report has been prepared for Aris Mining Corporation (Aris Mining) in compliance with the disclosure requirements of National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101) to disclose material updates to the Soto Norte Project (Soto Norte, the Project, or the Property) resulting from updated mineral resource and mineral reserve estimates and the results of a prefeasibility study of a smaller, more efficient development plan for the Project than was previously considered in a feasibility study titled NI 43-101 Feasibility Study of the Soto Norte Gold Project, Santander, Colombia prepared by SRK Consulting (UK) Limited, Sociedad Minera de Santander S.A.S. and SNC-Lavalin Inc. with an effective date of January 1, 2021 (the 2021 feasibility study). Soto Norte is an undeveloped, prefeasibility study stage underground gold-copper project where environmental permitting activities are underway.

This prefeasibility study outlines a long life underground gold mine with robust economics, low operating costs, and a design that reflects industry best practices in environmental protection and community partnership. The Soto Norte development plan has been specifically designed to balance scale and sustainability, and engineered to avoid impacts on the Santurbán páramo and regional watercourses. The Project will also generate significant long term benefits for Colombia, the department of Santander, and the municipalities of California, Suratá, and Matanza.

Two parallel zones of gold, silver, and copper mineralization known as Gigante and Mascota have been defined by 904 diamond drillholes for a total of over 375,000 metres (m) over a strike length of 2.6 kilometres (km) each down to a depth of approximately 800 m below surface. The mine will be developed over a strike length of 1.8 km at Gigante and 1.6 km at Mascota over a vertical range of 700 m.

The underground mine has been designed to produce ore using longitudinal open stoping with backfill, a safe, modern mining method, at a rate of 2,750 tonnes per day (tpd). Nearly half of the process tailings will be filtered and reused in paste backfill for underground mining, which both supports ground stability and reduces the volume of process tailings stored on the surface. The process water will be reclaimed from the tailings and reused in the processing plant, lowering water needs. The mined material will be transferred from the mine portal to the processing plant via an aerial rope conveyor, minimizing truck traffic, road dust, and the risk of material spillage into waterways.

As part of the Project’s commitment to local stakeholders, the process plant has been designed to produce at a rate of 3,500 tpd, of which 750 tpd is dedicated to processing mill feed purchased from contract mining partners from the local communities. This initiative provides a safe, regulated alternative to traditional artisanal processing and helps to reduce existing impacts in a region that suffers from untreated tailings releases into rivers. The designed throughput of 3,500 tpd, including the 750 tpd dedicated for the local community, supports strong investment returns, and is purposefully smaller than previous designs to reflect community input.

The processing plant will produce three saleable concentrate products including gold rich copper concentrates, pyrite concentrates, and gravity gold concentrates. No cyanide or mercury is required or will be used in the process, eliminating two of the most harmful pollutants in gold processing. By purchasing and processing material from contract mining partners, the Project will eliminate the need for the use of mercury in the neighbouring community, improve the quality of water, provide an efficient use of energy, and help ensure all tailings are managed in a safe, controlled manner in the local area.

The gold rich concentrates will be produced in a mechanically contained system, minimizing the risk of fine particles or process water entering local streams. No on site smelting or refining will take place, avoiding activities that generate harmful emissions or chemical residues. The concentrates are a stable, high grade semi-solid product, and will be securely stored, containerized, and shipped to international buyers.

The Project footprint is located 600 m horizontally outside of the current delimitation of the Santurbán páramo, where mining is prohibited, and approximately 350 m in elevation below it. While the Colombian government is in the process of redefining the Santurbán páramo boundaries, and these distances may change, the Project is outside of the Santurbán páramo boundaries. Comprehensive water studies have demonstrated that the underground mine will not affect the ecologically sensitive environment of the Santurbán páramo, as the shallow water at the páramo is not connected to the deeper groundwater at the mine.

 

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The Project has been designed with robust water management and protection as guiding principles. There is sufficient and readily available water within the Project area for all aspects of the operation including mining, processing, the camp, and other activities. Construction water will be sourced under permits from the La Baja Creek and Suratá River, which both have abundant water supply. During operation, the main source of water for the underground mine and its associated infrastructure will be from groundwater and the main source of water for processing will be from the adjacent Suratá River.

The Project plans to reuse, recycle, and return approximately 96.5% of the Project’s total water requirements back to the environment, resulting in a net water use estimated at 3.5%. The majority of the demand will be supplied by the Suratá River, which will supply approximately 2.8 litres per second of net make up water for the processing plant, representing 0.22% of the average flow of the Suratá River at the planned water access point near the village of Suratá, and 0.08% of the average flow of the Suratá River at Bucaramanga, the nearest city located 55 km downstream from the Project.

The Project includes a comprehensive water management plan that incorporates plans and programs tailored to each water application or activity with significant interaction with water to ensure that both the quality and quantity of local water resources are preserved throughout the life of the operation, and all potential impacts related to water use have been thoroughly identified, assessed, and addressed through prevention, mitigation, and compensation measures. The underground mine has been designed to minimize groundwater flows into the underground workings through advanced cover drilling and grouting ahead of mine development to identify and seal any water bearing structures before mining reaches them, greatly reducing potential inflow, and to manage, treat, and if required, safely return any captured water to the environment in compliance with the environmental standards and discharge permits. The process plant has been designed to minimize the use of water and to recycle both process water and the water obtained from the dewatering of the process tailings. The filtered tailings storage facility has been designed to divert rainwater runoff away from the facility and to drain and manage any subsequent dewatering of the tailings and any rainwater falling onto the facility. Continuous monitoring of water flow and quality will be undertaken with defined measures planned if any changes are detected. These strategies will help ensure that the current water flow rates within the ecosystem are maintained.

The peak workforce during Project construction is estimated at 2,292, plus 90 administrative staff and management. During operations, the workforce is estimated at 676 company personnel. The Project is targeting 60% of the workforce to be hired from the local community, 20% from the department of Santander, and 18% from other departments in Colombia.

The Project’s expected mine life of 22 years is based on the current mineral reserve estimate, and there are opportunities for future mine extension if additional mineral reserves are defined through continued exploration. There are numerous areas of high grade inferred material located adjacent to stopes designed around indicated material that could be targeted for exploration. An initial exploration drilling program of 35 drillholes for approximately 12,500 m is recommended to target the highest grade areas of inferred mineral resources, and those located in the upper areas of the mine, comprising 1.2 Mt at 12.50 grams per tonne (g/t) Au for 482,000 ounces, to potentially convert those volumes to indicated mineral resources.

Over its life, the Project is estimated to produce 4.3 million ounces (Moz) of gold, 18.8 Moz of silver, and 84.0 million pounds (Mlb) of copper in concentrates. The average annual gold production is estimated at 263 thousand ounces (koz) between years 2 and 10, with an average annual gold production of 203 koz between years 1 and 21.

The total estimated upfront capital expenditure is $625 million. The cumulative after tax net cash flow is estimated at $5.0 billion, including all initial capital costs, pre-production costs, sustaining capital costs, closure costs, value added tax (VAT), and contingency. At the base case assumption of $2,600 per ounce of gold, the life of mine average cash costs per ounce of gold are estimated at $345 and all in sustaining costs (AISC) per ounce of gold are estimated at $534. The Project has an after tax net present value at a 5% discount rate (NPV_5%) of $2.7 billion, an internal rate of return (IRR) of 35.4%, and a pay back period of 2.3 years.

The Project is estimated to contribute $2.6 billion in income taxes and $393 million in royalty payments to the Colombian government.

All dollar amounts presented in this technical report are expressed in U.S. dollars, unless otherwise indicated.

 

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1.2 Property description, location, and access

1.2.1 Location and access

The Project is located in the historic California – Vetas mining district, approximately 350 km north of Bogotá, the capital city of Colombia, 55 km northeast of the city of Bucaramanga, and 9 km northeast of the town of California. The Project is readily accessed year round by vehicle from Bucaramanga via 54 km of paved and unpaved roads to California and then by 9 km of unpaved road that passes through the centre of the Project. Smaller roads and foot trails provide further access throughout the Property, including 13 km of road connecting the processing plant and the underground mine access area.

Bucaramanga is readily accessible from Bogotá by 397 km of paved road, and connected to the city of Barrancabermeja, a city with a river port that is the preferred option for transporting concentrates to overseas buyers, via 115 km of paved road. Barrancabermeja is located 650 km on the Magdalena River from the seaport at Cartagena, one of the largest in South America. Bucaramanga is also connected to the city of Santa Marta on the Caribbean coast by 539 km of paved road, which is another potential concentrate transport route.

There are several daily domestic flights from Bogotá and Medellín, where Aris Mining maintains its executive and shared services office, to Bucaramanga, which also offers direct international flights to Panama City and Fort Lauderdale.

1.2.2 Mineral tenure, Aris Mining’s interest, surface rights, and obligations

There are 20 titles with a total area of 3,225.22 hectares (ha) associated with the Property, all of which are 100% owned by Proyecto Soto Norte S.A.S. (PSN), with the exception of title 14947, of which PSN owns an option for 80% of the title. PSN is a company existing under the laws of Colombia, of which Aris Mining is the Project operator and holds an indirect 51% joint venture interest with MDC Industry Holdings LLC (MDCIH), a wholly owned subsidiary of the investment company Mubadala Investment Company PJSC holding the remaining 49% joint venture interest.

The mining titles at the Project do not provide property or rights over the land, but the right exists to expropriate or impose an easement over the land through administrative and/or judicial proceedings if it is required to develop the Project. The preferred method for acquiring land at Soto Norte for project development will be to reach agreements with landowners following receipt of the environmental permits.

PSN owns land with a total area of 192 ha, of which 10 ha are shared with third parties, and leases a further 1 ha of land to support the activities at the Property.

Title 095-68 is the key title containing the Property’s mineral resources and mineral reserves, the planned underground mining infrastructure, and the surface infrastructure at the mine area. It has an area of 379.4 ha and the title expiry date is June 8, 2028. PSN will request an extension of the title in accordance with the terms of the contract.

Additional land purchases will be required for Project development and operation.

The work required to maintain the titles is dependent on the stage of the contract, such as performing exploration activities during the exploration stage. The title owner is required to comply with the environmental regulations and obtain all the necessary permits during the exploration stage, and the environmental license must be obtained for the construction and mining stages. Economic requirements include paying a surface fee during the exploration and construction stages and paying the royalty and obtaining an environmental mining insurance policy during the mining stage.

1.2.3 Royalties, agreements, and encumbrances

Royalties due to the Colombian state include a 4% royalty on 80% of the gold and silver produced and a 5% royalty for copper on 100% of the copper produced.

1.2.4 Significant factors and risks

On January 30, 2024, the Colombian Ministry of Environment issued Decree 044 which allows the Ministry to declare

 

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temporary reserve areas in certain parts of Colombia. To establish a temporary reserve area, a resolution must be issued by the Ministry detailing the area that is to be temporarily reserved. The Ministry issued Resolution 221 of 2025, amended by Resolution 239 of 2025, by means of which it declared a Temporary Reserve Area (TRA) in the Soto Norte region. The TRA will be in effect for two years, with a possible two year extension. While the TRA is in force, no new concessions or environmental permits may be granted by the mining or environmental regulators. During this period, the Ministry of Environment and Sustainable Development of Colombia must conduct environmental studies to determine whether to make the reserve area permanent. Notwithstanding the TRA, the Soto Norte Project may continue environmental studies, provided no environmental permit is required. Decree 044 and the TRA may delay licencing of the Soto Norte Project.

Decree 044 and the TRA resolutions are presently being challenged in administrative courts, with actions led by the Colombian Disciplinary Office, artisanal and small mining units, the Colombian Mining Trade Association, and the National trade association.

Additionally, the Administrative Tribunal of Santander issued a ruling in July 2025 in a class action proceeding recognizing the Santurbán páramo as a subject of personal rights and designating the Ministry of Environment as its legal guardian. While there is no direct impact on the Soto Norte Project, environmental licensing proceedings for the Soto Norte Project may be delayed or hindered because the Tribunal ordered that: (i) the Ministry of Environment must actively participate and protect the páramo in any licensing process, including through the use of administrative injunctions, (ii) all relevant environmental authorities must identify critical transition areas to the páramo in the Soto Norte region for water protection, and (iii) zoning regulations must exclude mining activities in “buffer zones” in alignment with the 2014 delimitation process. The ruling was appealed.

The Soto Norte Project remains several years away from development. With the completion of this technical report, PSN intends to present a fully redesigned project to the Colombian regulators following the conclusion of the environmental and technical studies currently underway.

Environmental effects have arisen from historical workings and ongoing informal mining activities and processing plants within the Project titles. Monitoring data show impacts on the La Baja Creek, which runs through the Project area. These include discharges from informal mining affected by acid rock drainage and/or metal leaching, and there is erosion and mobilization of sediments near the informal mine workings and processing areas. None of the environmental liabilities resulting from these informal operations conducted after the Project acquired the titles are the legal responsibility of the Project. PSN is responsible for managing environmental effects related to its own activities and for the effects of the previous titleholder activities. PSN is and will continue to keep working with the regulatory authorities to remediate damage wherever possible.

Except for the risks mentioned herein and in Section 4.7, there are no other known significant factors or risks that may affect access, title, or the right or ability to perform ongoing work programs on the Property, including permitting and addressing environmental liabilities, aside from the requirement to obtain future environmental licenses and approvals.

1.3 History

Artisanal miners holding small tenements within the Property mined on a small scale in the past. No production records exist, but an estimated 50,000 to 75,000 tonnes are believed to have been mined from the Property. Between 2010 and 2012, small scale production was reported at a rate of between 10 and 30 tpd. There has been no formal production at the Property.

In December 2005, Ventana Gold Corporation (Ventana) acquired small scale tenements from the artisanal miners and formed the La Bodega project. In December 2005, Ventana began the first modern exploration program comprising geochemical sampling, geophysical surveys, and exploration diamond drilling. Ventana disclosed a historical scoping study in November 2010, and by March 2011, a total of 378 diamond drillholes for 134,078 m had been completed.

In March 2009, EBX Group (EBX) began purchasing shares of Ventana, and on May 25, 2011, AUX Canada Acquisition Inc. (AUX Canada), an affiliate of EBX, acquired Ventana and changed the Project name from La Bodega to El Gigante. In October 2012, AUX Canada’s local subsidiary merged with Sociedad Bodega Ventana Baja, consolidating the Project under AUX Colombia S.A.S. (AUX Colombia). AUX Colombia drilled 431 diamond drillholes for 198,660 m between 2011 and 2013. AUX Colombia excavated an exploration tunnel between July and October 2012, as well as four drives into the Gigante and

 

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Mascota veins. AUX Colombia disclosed a historical mineral resource estimate in January 2013. In July 2013 AUX Colombia terminated all exploration activities, and the Project was placed on care and maintenance from mid-2013 to the first quarter of 2015.

In January 2012, MDCIH formed a strategic partnership with EBX through a preferred equity investment. In 2013, following the financial difficulties of EBX, MDCIH took ownership of the Project as a redemption on the original investment. In February 2015, MDCIH took ownership of AUX Colombia and on November 6, 2015, changed the subsidiary name to Sociedad Minera de Santander S.A.S. (Minesa), and changed the Project name to Soto Norte.

Between 2015 and 2018 Minesa undertook geochemical and channel sampling, and drilled 95 diamond drillholes totalling 42,498 m. No further exploration specific activities have taken place since 2018. Technical studies have been undertaken as required to support ongoing Project design studies.

The results of the Project diamond drillhole samples have been utilized for historical as well as the current mineral resource and mineral reserve estimate. Historical mineral resources have been estimated with effective dates of November 2010, July 2012, January 2013, February 2016, January 2017, July 2017, May 2019, and January 2021.

In August 2017 the first historical mineral reserve was estimated as part of a prefeasibility study, based on the historical January 2017 mineral resource estimate. In January 2021 the second historical mineral reserve was estimated as part of the 2021 feasibility study, based on the historical May 2019 mineral resource estimate.

None of these historical mineral resource and mineral reserve estimates are current. They should not be relied on and have been superseded by the current mineral resource and mineral reserve estimates disclosed in this technical report.

On April 12, 2022, Aris Mining (formerly Aris Gold Corporation) acquired a 20% joint venture interest in Minesa and became the Project operator. On November 2, 2023, the Project was renamed to PSN. On June 27, 2024, Aris Mining acquired an additional 31% joint venture interest in the Project, increasing its total ownership to 51%, with MDCIH retaining the remaining 49%.

1.4 Geological setting, mineralization, and deposit types

1.4.1 Regional, local, and property geology

Regionally, the Property is located in the western branch of the Eastern Cordillera of the Colombian Andes, where the geology is characterized by the creation of subduction zones and associated magmatism, uplifted blocks, and compressional faulting. The north-northwest trending Santander Massif hosts the Soto Norte mineralization, bound by the Bucaramanga fault to the west and the Socota-Santander fault to the east. The Project geology is related to magmatic events and contact metamorphism between these two faults.

Locally, the Santander Massif at the Project comprises three major geological units, including the Bucaramanga Complex comprising paragneisses, migmatites, amphibolites, quartzite, marbles, and granulates; the Central Santander Plutonic Group comprising intrusive calc-alkaline rocks ranging from tonalites, granodiorites, and leucogranite; and sedimentary rocks.

District scale faulting forms topographic relief and the dominant northeast trending faults, which broadly control the shape of the intrusive complex. The principal faults include the La Baja, Mongora, and Cucutilla faults, which are interpreted to belong to a wider regional structural corridor that acts as one of the controls on mineralization throughout the California – Vetas mining district. Intrusive rock on the north side of the La Baja fault, and gneiss on the south side of the fault, is the host of the Soto Norte mineralization.

Mineralization at the Property is hosted in gneisses of the Bucaramanga Complex and leucogranites of the Santander Plutonic Group, and mostly occur within tectonic-hydrothermal breccia bodies emplaced in a dilatant structural setting.

1.4.2  Mineralization

The faults hosting the parallel Gigante and Mascota mineralization trends represent two linking structures between the

 

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principal faults, with the Mascota mineralization hosted by the La Rosa fault zone and the Gigante mineralization hosted by the La Baja fault zone. Mineralization took place during active faulting along these structures. The faults converge at depth and are indicated to join into a single structure. Numerous minor faults are present, some of which are mineralized and have been partially exploited at the surface by artisanal and small scale miners.

Mineralization at the Property comprises parallel anastomosing veins within the fault systems, with variable widths and characteristics. Veins at Mascota have open-space filling textures, with hydrothermal brecciation and brecciated fragments of wall rock. Veining in the Gigante structure is mostly characterized by more compact, less vuggy, and often banded textures and is characterized by more heavily altered wallrock and clay content. Aserradero is a smaller, lower grade deposit located to the southeast of Mascota and Gigante.

Gold and electrum have a strong relationship with fine, crystalline pyrite and occur either free with the gold, adhering to pyrite particles, or encapsulated within the pyrite crystal lattice. Copper sulphides appear to have a partial affinity for pyrite but have much less of an association with gold than pyrite. Silver occurs principally as silver sulphosalts, pyrargyrite, and proustite. Copper occurs principally as enargite and to a lesser extent as bornite, chalcopyrite, chalcocite, and tetrahedrite-tennantite.

The Mascota and Gigante vein trends cover a strike extent of 2.6 km and have been drilled to a depth of approximately 800 m below the surface. The width of the veins is variable and averages between 1 and 3 m. The mineralized structures extend to the surface and are open at depth and along strike, resulting in a high exploration potential for expansion from future underground drilling stations.

1.4.3 Deposit types

The Soto Norte deposit is considered a high-sulphidation epithermal deposit, with gold, silver, and copper occurring mainly in sulphides. The deposit is related to porphyry stocks and dikes that crosscut older sedimentary, igneous, and metamorphic rocks. The hydrothermal source fluids flowed through fault related pathways, generating background propylitic and phyllic alteration of the local rocks during mineralization, followed by silicification and argillic alteration in the centre of the main veins, zoning outward to intermediate argillic and propylitic alteration that formed during the principal stages of mineral deposition. This model has formed the basis of the past exploration plans that have followed the vein trends along strike and down dip.

1.5 Exploration

Ventana began surface and underground geochemical sampling in early 2006, accompanied by ground magnetic and induced polarization (IP) geophysical surveys in the area of Gigante, followed by a ground magnetic and pole-dipole IP resistivity survey. Surface diamond drilling started in August 2006, with 143,568 m completed by the end of March 2011.

Between 2011 and 2013, AUX Colombia completed a further 200,124 m of diamond drilling over a strike length of 2.5 km.

In February 2012, an airborne magnetics and radiometrics survey was completed over Gigante and the surrounding area. A ground magnetics and IP survey was completed in March 2012 in the Gigante area.

The combined ground magnetics data shows strong anomalies with a northeast-southwest trend that coincides with the general trend of the mineralization and geochemical sampling results. The combined IP results show similar trends and indicate that the anomalies continue to the southwest through the Galway and Calvista properties, also owned by Aris Mining, and onwards to the town of California.

AUX Colombia completed mapping and sampling during excavation of the mine portal exploration tunnel and the existing tunnels into Gigante and Mascota.

Between 2015 and 2018 Minesa collected mobile metal ion soil, rock, and channel samples taken from historical mine workings. The combined Project geochemical samples confirm the northeast-southwest trend of gold mineralization subparallel to the La Baja Creek, and higher grade zones on the northeast limits towards the La Bodega area.

95 diamond drillholes were completed, totalling 42,498 m. Twelve geotechnical drillholes were completed to provide

 

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geological and geotechnical information for a previously considered tunnel access.

No other exploration work has taken place since 2018.

1.6 Drilling

Diamond drilling was carried out by a range of different contractors during 2006 to 2018, for a total of 904 holes for 375,235 m. Drillholes were collared at HT diameter (71 millimetres (mm)) or HQ diameter (63.5 mm), then reduced as drilling conditions allowed to NT diameter (58.9 mm) or NQ diameter (47.6 mm). In a few cases the diameter was reduced to BT diameter (40.8 mm) or BQ diameter (36.5 mm).

No drilling for the purposes of mineral resource definition has been completed since 2018.

The drilling grid was first completed at 100 by 100 m spacing and later tightened to 50 by 50 m, with further tightening to 25 by 25 m on shallower areas above 150 m below the surface. At depth the drilling intersections remain relatively wide at 50 to 100 m, which is a function of the steep intersection angles required by the steep topography. Further infill drilling will be completed after underground development is in place to provide a better drilling intersection.

The mineralized structures are open at depth and along strike, with high exploration potential to target the deep structures from underground drilling stations.

As the drillhole intersections through the vein interpretations are used as an input into the mineral resource estimate, the relevancy of the raw drillhole sample assay results are superseded by the mineral resource estimate and are more meaningfully described in the context of the mineral resource estimate.

1.7 Sampling, analysis, and data verification

1.7.1 Sample preparation

The diamond drill core sampling process was similar across Project owners with minimal differences. Once logging was completed, the core was marked for cutting with a diamond bladed core saw, and the right hand side of the half core pieces were placed in plastic sample bags. For broken fragments, half the volume was selected by hand. Intervals with clay or unconsolidated material were split vertically with a knife while still saturated. The sampling intervals and assay results were recorded in the core logs. After cutting, the left hand side of the half core was placed back in the core box for storage. Although the standard sample length was 1.0 m, it was adjusted to align with geological contacts.

1.7.2 Quality assurance and quality control

The quality assurance, quality control (QAQC) submission rate increased over time as the Project owners prioritized data integrity and reliable assay results. QAQC samples from Ventana and AUX Colombia involved the laboratory selecting a pulp reject split of the original sample as directed by the Project’s geologists. Coarse blanks and commercial standard samples were also submitted.

Minesa implemented a rigorous QAQC system to ensure the validity, accuracy, and reliability of the sample assays. Analytical control measures included the use of certified reference materials, coarse and fine blanks, coarse and pulp reject duplicates split by the laboratory, and quarter core samples of the second half of the core sample.

Between 2006 and 2011, the QAQC insertion ratios were less than 10%, but increased to between 11 and 19% between 2012 and 2018, coinciding with Minesa’s ownership of the Project and their procedural improvements. Over the entire sampling history, 37 different standards were submitted with the results showing a low failure rate within acceptable parameters, with close to zero bias in some of the most representative standards. Less than 10% of the results exceeded three standard deviations of the certified value. The cause of these failures cannot be definitively determined but may be related to a mislabelling of the standard. No significant bias was observed. Blanks initially comprised coarse blanks until AUX Colombia began submitting fine blanks. The results of the fine blanks were satisfactory. Duplicate sample submissions increased over time and included coarse and pulp rejects and quarter core samples. Pulp duplicates showed high variability attributed to the presence of coarse gold. Variability was also noted to a lesser extent in the quarter core samples. The

 

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variability was not observed in the coarse duplicates, suggesting potential issues with the homogenization or splitting process during the selection of the pulp duplicates.

1.7.3 Security measures

Security measures for sample handling and chain of custody have been similar across Project operators. Ventana’s chain of custody was maintained and monitored throughout the process with half cores selected for analysis, bagged, sealed, and then placed in larger bags, which were also sealed. Storage on site was in a locked core shed with 24 hour security until the samples for the entire drillhole were shipped as a single batch for sample preparation. The laboratory verified the security seals and signed off on receipt of the samples.

AUX Colombia included a chain of custody protocol where the names of all persons handling drill core were recorded on forms. Upon receipt of the sample at the laboratory, the sample barcode was scanned.

The Minesa chain of custody security protocol included that a member of the geological staff always accompanied the sample during transportation before handing them over to the laboratory for sample preparation. The samples were then transported by DHL to the analytical laboratory.

1.7.4 Analytical procedures

All of the Project diamond drill core samples have been prepared and analyzed by independent commercial laboratories.

The details of Ventana’s drillhole sample preparation methods at the laboratory are unknown, but the samples were analyzed using fire assay for gold and silver as well as a 36 element ultra trace package using hot aqua regia digestion and inductively couple plasma – mass spectrometry (ICP-MS).

AUX Colombia’s drill core samples were crushed and pulverized at ALS Chemex Bucaramanga then shipped by air courier to ALS Chemex in Lima for analysis, which held ISO 9001 and 17025 accreditations. The entire sample was crushed, then a 500 g split was collected with a riffle splitter and pulverized. The samples were assayed for silver and gold using fire assay with atomic absorption (AA) finish. Any sample with a gold grade greater than 5 g/t and a silver grade greater than 100 g/t was re-assayed using fire assay with gravimetric finish. 51 trace elements were assayed using aqua regia and ICP-AES/ICP-MS.

Minesa’s drill core samples were prepared by drying, crushing, quartering with a Jones splitter, and pulverizing the subsample. The samples were assayed for gold using fire assay with AA finish and any gold assay greater than 100 g/t was re-assayed with gravimetric finish. Silver assays with grades greater than 100 g/t were re-assayed using aqua regia digestion with AAS finish, and samples greater than 1500 g/t were re-assayed using fire assay with gravimetric finish.

1.7.5 Data verification

In 2016, an independent consulting firm conducted a reanalysis of 922 quarter core samples and 1,148 pulp duplicates at an independent check laboratory, including standard controls in both sample types, and conducted a thorough review of the database data collected prior to 2014. The results indicated a low bias in the primary laboratory compared to the check laboratory, although silver assays showed higher variability. The results from the standard samples showed low bias and fell within acceptable limits.

For the current technical report, the qualified person responsible for geology verified the geological data supporting the mineral resource and mineral reserve estimates through the personal inspection and through collaboration with the Project team, including:

 

•

cross validation of the database entries with selected original laboratory certificates;

•

reviews of the geological and geographic environment of the Project;

•

reviews of the nature and extent of all exploratory work completed by the Project owners, including those relevant to the current mineral resource estimate;

•

reviews of mineralized and non-mineralized drill core intersections;

 

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•

reviews of standard operating procedures related to drilling, sampling, and analytical processes covering several stages in the sampling and assaying chain from raw samples to prepared assay pulps; logging, re-logging, core sampling processes, analytical QAQC controls, and chain of custody; and bulk density determination methods;

•

reviews of sample storage facilities for drill core, coarse rejects, and pulp rejects;

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reviews of database management processes; and

•

independent sample checks of drill core and pulp rejects.

Based on the personal inspection and geological database review, the qualified person has found that the drilling, logging, and sampling practices meet acceptable international standards, thus concluding that the sample preparation, safety protocols, and analytical procedures implemented for the Project provide an adequate current basis for the mineral resource estimate. The following were observed:

 

•

the geology and mineralization controls are well understood and appropriately considered during drilling and geological interpretation;

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no material issues were identified in the database;

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the translation of previous drillhole collar coordinates to the current coordinate system and the on site inspection verified their accuracy with no concerns regarding the transformation method;

•

survey review identified some anomalous measurements, which were examined and appear to be related to geological factors. Other anomalous measurements were not reviewed in detail but they do not appear to significantly impact the survey. These should be investigated further as the Project work progresses;

•

assay results compared with certificates show minimal inconsistencies;

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in the early years of drilling, the QAQC sample insertion rate was limited, but this has been progressively enhanced to meet industry standard protocols;

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although the early drilling campaigns included limited QAQC samples, the overall assessments show no contamination issues with coarse and fine blanks during crushing and pulverization. Standard samples exhibit acceptable accuracy, though a few extreme outliers may be attributed to coding errors. Quarter core and coarse reject duplicates demonstrate good precision while pulp duplicates show lower precision, likely due to issues with homogenization or splitting during the pulverization stage; and

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independent sample checks by the qualified person included the re-assay of 20 pulp samples, which confirm consistency with the original grades. Six quarter core and two coarse reject samples were also re-assayed, showing some differences, generally with lower values. These variations, though not entirely clear, are likely associated with natural gold variability, the smaller sample size of the quarter core compared to the half core original sample, and sampling processes. The mineralization evidence is strong, with no significant indications of bias or errors in sample handling.

In the opinion of Kate Kitchen, the qualified person responsible for this disclosure, the data used for the purpose of estimating the mineral resources and mineral reserves and the development of the economic analyses are sufficiently reliable.

1.8 Mineral processing and metallurgical testing

1.8.1 Testwork history

Several metallurgical testwork programs have been undertaken between 2009 and 2018 to support the metallurgical assumptions utilized for the progressive Project studies, utilizing samples that were representative of the growing mineral resource as it was known at the time of the studies. These studies included processing method trade off studies as well as refinements of the selected operating parameters, as the properties and response of the samples under the testwork conditions were increasingly better understood.

The first two testwork programs considered flowsheets utilizing cyanidation. Testwork was conducted to support a scoping study by Ventana in 2010 that proposed a flowsheet consisting of comminution, gravity separation, and flotation to produce separate copper and pyrite concentrates, intensive cyanide leaching of the gravity concentrate, cyanide leaching of the combined copper cleaning tailings and pyrite concentrates to recover copper and silver via sulphide precipitation and gold through an adsorption – desorption recovery circuit. Testwork was later undertaken to support a scoping study by AUX Colombia in 2012 that proposed a flowsheet consisting of comminution, gravity separation, and flotation to produce a bulk

 

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sulphide concentrate, with pressure oxidation of the concentrate followed by solvent extraction and electrowinning to produce copper cathode, and cyanidation for gold recovery.

The remaining testwork programs eliminated the use of cyanidation for environmental reasons. Testwork was conducted to support trade off studies and a prefeasibility study by Minesa in 2017. The initial trade off study selected flotation as the preferred process route, due to capital costs and environmental advantages over flotation followed by pressure oxidation and cyanide leaching. Further trade off studies directed the work towards the production of sequential copper and pyrite gold flotation concentrates.

Testwork was undertaken to refine and parameterize the flowsheet selected during the 2017 prefeasibility study, comprised of comminution and flotation to produce separate copper and pyrite concentrates, and to validate the key metallurgical assumptions, to support a feasibility study undertaken by Minesa in 2021. In 2024, a gravity gold circuit trade off study was conducted based on previous testwork undertaken in 2010, 2017, and 2018 to justify the inclusion of a gravity concentrator in the flowsheet proposed for the current prefeasibility study.

The metallurgical testwork to date has been conducted on a wide range of samples representative of the material expected to be processed over the life of mine. The studies have been conducted to a sufficient quality and extent to support the process flow sheet presented in this prefeasibility study and has been utilized to support the previous feasibility study. The results of this testwork has been estimated into the mineral resource and mineral reserve block model, with the estimated variable used to develop the production schedule and economic analyses.

The level of testwork conducted to date that supports the development of robust process design criteria which has resulted in a flowsheet that recovers the required amount of gold, silver, and copper at saleable grades meets the typical expectations for a prefeasibility level of study. The flowsheet developed to produce a separate copper and pyrite concentrate through sequential flotation is viewed as the most technical and economically viable solution while mitigating risk.

1.8.2 Mineralogical testwork

Mineralogical testwork indicates that the processed ore will have fine to very fine grained gold present as native gold, electrum, and tellurides, mostly locked in other minerals or at the grain boundaries of the minerals, predominantly sulphide minerals. Silver is present in native gold, electrum, and telluride, as well as sulphosalts with antimony, arsenic, and bismuth, and is more correlated with copper. Pyrite is the most abundant sulphide mineral and is significantly coarser than the other sulphides. Enargite is the most abundant copper bearing mineral with the remaining copper distributed between bornite, covellite, chalcocite, and chalcopyrite. With the majority of gold particles associated with sulphide minerals, high recoveries by flotation are expected, and free gold and some of the larger entrained gold can be recovered through gravity. Fully silica encapsulated gold, which accounts for an estimated less than 1% of the mill feed, cannot be recovered through flotation, but some may be caught in a gravity circuit. Roughly half of the gold is associated with copper sulphide minerals and will be captured in the copper concentrate while the remaining gold associated with pyrite and chalcopyrite will be recovered in the pyrite concentrate. Silver is expected to be recovered in greater quantities in the copper concentrate.

1.8.3 Comminution testwork

Comminution testwork shows that the ore is highly variable and moderately hard for semi-autogenous grinding (SAG) and relatively hard for ball milling, compared to other ores. The expectation is that the ore will become increasingly harder at greater depth. The Bond Work Index results indicate that the material becomes abnormally harder at finer sizes, resulting in a higher energy requirement and a coarser grind product from a SAG mill, resulting in reduced throughput. The addition of a pebble crusher to a SAG will increase throughput. The current process flowsheet has made allowance for a SAG mill in closed circuit with a pebble crusher and a ball mill in closed circuit with a cyclone cluster, which greatly mitigates identified risks.

1.8.4 Gravity separation and flotation testwork

Gravity separation and flotation testwork shows that both Mascota and Gigante material respond well to flotation.

 

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The findings of the gravity gold circuit trade off study were that there is gravity recoverable gold present in the Soto Norte ores and that the inclusion of a gravity circuit does not appear to have any adverse impact on the overall recovery of the economic minerals. The main concern is the lack of data from Gigante and the marketing effects for selling copper and pyrite concentrates with a reduced gold content. The benefits of a gravity circuit include the reduction of variability of gold in flotation, lowering the mass pull and producing a higher grade gold-silver concentrate while maintaining the overall recovery of the system, quicker and more pronounced process optimizations, and is unaffected by variations in clay content of the mill feed. The incorporation of a gravity concentrator in the processing flow sheet will not have any significant impact on the downstream circuit and will significantly mitigate the risk of losing coarser gold to the flotation tailings. This could potentially facilitate the recovery of approximately 15% of the gold either in the form of a gold-silver concentrate or as a doré, instead of recovering to the copper concentrate, which is economically more favourable. Other economic benefits include higher gold payabilities from a doré product compared to a concentrate product on the order of between 3.9 and 9.9%, minimal or no penalties, and quicker access to cash flow. The cost benefits, at a high level, outweigh the relatively low capital cost requirements for a gravity circuit and gold safe room, and negligible operating costs, and indicate an increase in revenue of approximately 4 to 10%.

1.8.5 Deleterious elements

Potential deleterious elements that can derive economic penalties include arsenic present in enargite/tetrahedrite that will be recovered reaching levels of up to approximately 3% into the copper concentrate; antimony present in tetrahedrite that may be present in the concentrate in amounts that may incur penalties; zinc mostly present in sphalerite that is present in higher quantities in certain parts of the deposit but has only a minor association with copper sulphides and pyrite; bismuth present in a wide range of minerals; cadmium, and mercury that are present in certain areas of the deposit. Grade control will be required to mitigate penalties.

Flotation testwork has been conducted of sufficient quality to parameterise the circuit including deriving the recoveries of minor elements, including deleterious elements, including the deportment of deleterious elements such as cadmium, mercury, zinc, bismuth, antimony, and arsenic, which may incur penalties although they are not deemed to pose a significant risk to the economic outcomes. There are no known processing factors or deleterious elements that could have a significant effect on the economic extraction of the ore that has not been considered and accounted for in the processing plan and economic model.

1.8.6 Metallurgical recovery

For design and economic analysis purposes, average metallurgical recoveries are estimated at 92.8% for gold, 88.8% for silver, and 92.8% for copper.

1.9 Mineral resource and mineral reserve estimates

1.9.1 Mineral resource estimate

The mineral resource estimate has been tabulated using a cut-off grade of 1.6 g/t Au, based on a gold price of $2,600 per ounce, an overall gold metallurgical recovery of 92.8%, a mining cost of $42 per tonne, a processing cost of $22 per tonne, a general and administration (G&A) cost of $20 per tonne, and an effective 3.7% gold royalty.

The mineral resource estimate is constrained within mineable stope optimizer shapes generated at a 1.6 g/t Au cut-off grade and using a 3.8 m minimum mining width, and is inclusive of material below 1.6 g/t Au within the shapes.

The Soto Norte mineral resource estimate effective August 18, 2025 is shown in Table 1-1.

 

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Table 1-1   Soto Norte mineral resources effective August 18, 2025

 

Classification		Tonnes (Mt)				Gold grade (g/t)				Silver grade (g/t)				Copper grade (%)				Contained gold (Moz)				Contained silver (Moz)				Contained copper (Mlb)
Measured			3.8				7.99				36.8				0.25				1.0				4.6				21.4
Indicated			35.2				5.29				27.3				0.18				6.0				30.9				137.8
Measured  + Indicated			39.0				5.55				28.2				0.19				7.0				35.5				159.2
Inferred			25.1				4.81				24.6				0.13				3.9				19.9				74.5

Notes: •  Totals may not add due to rounding. •  Mineral resources are inclusive of mineral reserves. •  Mineral resources are not mineral reserves and have no demonstrated economic viability. •  A gold price of $2,600 per ounce was used for the mineral resource estimate. •  The mineral resource estimate utilized a gold cut-off grade of 1.6 g/t. •  The mineral resource estimate was constrained within mineable optimizer shapes generated at a cut-off grade of 1.6 g/t Au and using a 3.8 m minimum mining width, and is inclusive of material below 1.6 g/t Au in the shapes. •  The mineral resource estimate was prepared by Kate Kitchen, MAIG of Mining Plus who is a qualified person as that term is defined by NI 43-101. •  There are no known environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or other relevant factors or risks that could materially affect the mineral resource estimate or the development of mineral resources.

1.9.2 Mineral reserve estimate

The mineral reserve estimate for the Soto Norte Project effective August 18, 2025 is shown in Table 1-2.

Table 1-2   Soto Norte mineral reserves effective August 18, 2025

 

Classification		Tonnes (Mt)				Gold grade (g/t)				Silver grade (g/t)				Copper grade (%)				Contained gold (Moz)				Contained silver (Moz)				Contained copper (Mlb)
Proven			2.6				8.78				37.1				0.25				0.7				3.0				14.2
Probable			17.7				6.72				31.4				0.19				3.8				17.9				75.0
Proven  + Probable			20.3				7.00				32.1				0.20				4.6				20.9				89.2

Notes: •  Totals may not add due to rounding. •  A gold price of $2,200 per ounce was used for the mineral reserve estimate. •  The mineral reserve estimate was constrained within mineable optimizer shapes and utilized a cut-off grade of 2.0 g/t Au. •  The mineral reserve estimate was prepared under the supervision of and reviewed by Peter Lock, FAusIMM, CP, of Mining Plus, who is a qualified person as that term is defined by NI 43-101. •  Other than as disclosed in this technical report, there are no known mining, metallurgical, infrastructure, permitting, or other relevant factors or risks that could materially affect the mineral reserve estimate or the potential development of the mineral reserves.

1.10 Mining operations

The planned mining method is longitudinal open stoping with waste rock fill, cemented rock fill, or paste fill to maximize reserve extraction while maintaining a safe, modern, and efficient mining environment, and is planned to have a production rate of 2,750 tpd, in line with the processing plant capacity dedicated to the underground mine. The paste fill will utilize

 

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10.2 Mt of process tailings, just under half of the total tailings generated at the process plant. The total annual material movement of ore and waste has been limited to a maximum of 2 million tonnes.

A 5.5 m wide, 5.5 m high, 4 km long central decline from the surface utilizing the existing portal is planned for the main transportation route for personnel and equipment, and extends to the full depth of the mine design over a vertical range of 700 m. Ore and waste rock will be crushed underground then transferred to the surface by a service raise and then conveyed on the rope conveyor to the processing plant. The primary underground infrastructure, including ventilation shafts, material handling systems, and service facilities is strategically positioned along the central decline to support efficient operations.

The mine will be developed over a total strike length of 1.6 km at Mascota and 1.8 km at Gigante. From the central decline, access drives will extend to ore drives or footwall drives. Footwall drives in waste rock will be developed to establish ventilation circuits, for the transport of waste rock fill, and for access to lower grade stopes in the later stages of the mine. Where possible, a parallel ore drive will be developed in ore to access the stopes instead of a footwall drive in waste rock. This will allow access to lower grade stopes past the previously mined and backfilled higher grade stopes and reduce the overall development requirements. The use of parallel footwall or ore drives allows for multiple stoping fronts, ensuring a continuous and systematic extraction process with operational flexibility. Between 5 and 20 active stopes per month are required to sustain a processing rate of 2,750 tpd, depending on the contribution of development ore and the width of each stope. The stope dimensions have a 15 m length, with sub-level intervals ranging from 20 to 25 m in the upper areas of the mine and 30 m in the lower areas. A minimum stope width of 2.5 m was planned. 50% of the stopes are less than 5 m wide, 40% of the stopes are between 5 and 10 m wide, and 10% are greater than 10 m wide. The average stope comprises 6,000 tonnes. The stopes were divided into panels with vertical heights ranging between 90 and 100 m and scheduled using a bottom up mining plan within each panel.

The Project design has considered the requirement to avoid potential groundwater drawdown in the páramo and to protect the aquatic ecosystem of the La Baja Creek. To mitigate these risks, underground grouting is planned to minimize groundwater infiltration into the mine. Advanced cover drilling and grouting during mine development will be undertaken to enable early identification and pre-grouting to seal any water bearing structures to limit groundwater flows into the underground workings.

Any groundwater in the mine will be collected and managed in two separate systems, one for clean ground water and another for water that has come into contact with mining activities. Both streams will undergo water treatment before it is safely returned to the La Baja Creek, if required. During periods of low seasonal flow, treated water from the underground will be used to supplement the La Baja Creek, based on monitoring data.

1.11  Processing and recovery operations

The processing plant is designed to treat plant feed throughputs of a nominal 2,750 tpd and a maximum 3,500 tpd. The processing plant will receive 2,750 tpd of crushed run of mine ore from the Soto Norte underground mining operation, and can receive an additional 750 tpd of mill feed purchased from contract mining partners, to produce three saleable products and one waste product, including a gold concentrate from a gravity gold operation, a copper concentrate from a copper flotation operation, a pyrite concentrate from a pyrite flotation operation, and a tailings product for disposal in the filtered tailings facility and to create paste backfill for the underground mine. For design and economic analysis purposes, average metallurgical recoveries are estimated at 92.8% for gold, 88.8% for silver, and 92.8% for copper.

No cyanide or mercury will be used at the Soto Norte processing facilities. The processing circuit comprises primary ore crushing at the underground mine, ore transport from the mine portal to the process plant on the rope conveyor, receipt of mill feed purchased from contract miners at the process plant, primary grinding in a SAG mill with a supporting pebble crusher, secondary ball mill grinding, an upfront gold gravity recovery circuit to recover up to 15% of the coarse gold-silver particles and to produce a filter cake, and a two stage sequential flotation circuit to recover fine gold, silver, and copper in separate copper and pyrite concentrates.

A target grade of 16% for the copper concentrate has been set on the basis of testwork results as well as considerations for maximizing the gold content in the copper concentrate and reducing penalty element concentrations. Potential penalty elements considered in the economic analysis include arsenic, bismuth, cadmium, antimony, and likely zinc, with payments for contained copper and gold anticipated to be far in excess of any potential penalties. The non-sulphide waste content of the concentrates will be restricted to 10%.

 

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1.12 Infrastructure, permitting, and compliance activities

1.12.1 Mine infrastructure

The underground infrastructure will include:

 

•

a centrally positioned workshop strategically located off the decline and fully equipped for maintaining all underground equipment;

•

an explosives magazine strategically located adjacent to the workshop for the storage of ammonium nitrate and fuel oil (ANFO) and separate secure storage compartments for detonators to ensure the strict segregation from other explosives materials. A fully automated fire suppression system will be installed and configured to activate immediately upon detection of smoke. The explosives magazine will be designed, constructed, and operated in compliance with the Colombian explosives regulations;

•

a permanent fuel storage bay with the capacity to store 10,000 litres of diesel and 2,000 litres of hydraulic oil and temporary skid mounted fuel storage units positioned on active levels to facilitate efficient refuelling;

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chambers designed for servicing all underground equipment;

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a rock crusher chamber for reducing the ore and waste size;

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an underground rope conveyor system to transport crushed waste and ore rock to the surface;

•

a paste fill plant for backfill and ground support operations and a paste fill reticulation system to deliver the paste fill to the stopes;

•

wash bays for cleaning mobile equipment;

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lunchrooms and shift supervisor offices located on the primary intake ventilation circuit that can be used for safe firing areas and fresh air bases;

•

stores for the supply of spare parts and consumables;

•

ore and waste passes to streamline the handling of ore and waste material;

•

sumps and pump stations for effective water management and dewatering operations;

•

service holes to facilitate the routing of utilities and services; and

•

portable or fixed refuge chambers installed at intervals such that the workers are never more than 750 m away from the nearest refuge chamber to take refuge in the event of a mine emergency, and escape ladderways installed in a dedicated central escapeway, to provide a second means of egress in the event of a mine emergency.

1.12.2 Rope conveyor system

The rope conveyor system is a proven, efficient, low footprint, low impact, and state of the art solution for material and cargo transportation. Environmental and community impact benefits include its silent operation, the elimination of road construction and related traffic and dust and exhaust emission issues, and minimal land disturbance restricted to the tower bases. The covered conveyor minimizes dust generation as material remains stationary during transport, and the system allows for straightforward closure and site rehabilitation at the end of its life. Economic and operational benefits include low capital and operating cost requirements, and relatively simple construction logistics. The straightforward design has only a limited number of moving parts, reducing the potential for defects, minimizing inspections and maintenance, and increasing operational availability. The majority of the maintenance can be carried out in a safe environment at the station.

The planned Doppelmayr designed bi-directional rope conveyor system has a nominal capacity of 3,000 tpd and a maximum capacity of 5,500 tpd for transporting ore and waste rock from the mine portal to the processing plant, a nominal capacity of 1,080 tpd and a maximum capacity of 2,400 tpd for transporting tailings from the processing plant to the mine for use as backfill, and a capacity of 140 tpd for the transport of consumables from the processing plant to the mine. The system will be used to carry the high voltage power and fibre optic cables. The automated system will have a length of 7,100 m.

1.12.3 Process support facilities

The process support facilities will include a waste receiving area at the rope conveyor station, dedicated receiving areas for underground ore and mill feed purchased from contract mining partners, the milling circuit, the process plant, services, accommodation, storm water pond, roads, the main power supply, and an existing military base.

 

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The ore and waste from the underground mine will be transported from the mine portal to the processing facilities on the rope conveyor. Waste material will be diverted to a stockpile and then transported by truck for the construction of the filtered tailings storage facilities and for use as engineered fill in terraces.

The milling circuit facilities will include the ball and SAG mills, conveyors, pebble crushers, and space for a gold safe room. The process facilities will include the flotation circuits, reagent storage facilities, water treatment facilities, power supply, a weigh bridge, thickening and filtration facilities, roads, and a tailings pump line. A dedicated, approximately 6 km long route is planned for the tailings line with spillage risk mitigation features including a containment channel and access road for maintenance, and will also be used for an overhead line supplying power from the main substation to the water intake, filter plant, and ancillary equipment.

The service area will include workshop, warehouse, mobile equipment workshop, outdoor storage yard, fuel station, offices, wash bay, diesel storage, solid waste disposal yard, modular sewage treatment facility, access gate, and soccer field.

The accommodation area will include the accommodation blocks to house 170 people, mess hall, entertainment area, gym, clinic and emergency response building, and core sheds.

1.12.4 Filtered tailings storage facilities

Multiple potential tailings storage facility locations have been considered and engineered for the Project over time. Currently, the facility location has shifted from the 2021 feasibility study location and its development is now planned for one of the past alternative sites, in a valley surrounded by steeply sloped mountainous terrain, approximately 3.5 km to the south of the processing facility. The valley side slopes are moderately steep, while the slopes along the valley bottom are shallower. The location is primarily in a grassland area, with areas of dense shrubs and trees present along the upper reaches of the tailings basin.

The Project and the facility site are located in a high seismic region. A site-specific seismic hazard evaluation for the Project has been undertaken and the analyses were utilized for the current prefeasibility study engineering.

Knight Piésold developed a water balance model using climatic and hydrologic data to simulate water transfers and storages. The water balance simulations represent a range of possible flows and volumes over time. A sensitivity analysis was performed to estimate the variation of maximum volumes required to be stored in the contact water collection pond. Hydrologic analyses were undertaken by Knight Piésold to estimate peak flows for the design of hydraulic structures.

Deterministic, limit equilibrium slope stability analyses were also advanced by Knight Piésold on the facility embankment, tailings stack, and contact water collection pond dam under a variety of loading conditions. The findings from the stability assessment were incorporated into the facility design to confirm acceptable slope stability.

Knight Piésold conducted prefeasibility study engineering of the filtered tailings facility and associated contact water collection pond, haul road, and surface water management structures. The civil design components of the facility include the foundation and embankment abutment preparation, embankment, tailings stacking plan, geosynthetic liner system, drainage systems, contact water collection pond, and ancillary infrastructure including roads and surface water management channels. The facility design meets slope stability requirements as guided by the Canadian Dam Association and the International Committee on Large Dams, standards that are internationally recognized as best practice and provide detailed technical design and risk management criteria. The facility has a capacity of 11.8 million tonnes, sufficient to accommodate the current mineral reserve requirements of 10.3 Mt of combined process tails and waste rock. Additional storage capacity may be required in the future, depending on the amount of any future mineral reserves discovered through exploration drilling programs and on the volume of material purchased from contract mining partners.

The facility will comprise a tailings basin formed by natural topography, excavations into existing ground, placement of grading fills, and containment embankment at the downstream end of the tailings basin constructed of structural fill. The entire tailings basin and most of the upstream face of the containment embankment (all of the surfaces that will be in contact with tailings) will be lined with a composite liner comprising geomembrane overlying a layer of compacted low-permeability soil. A temporary tailings storage area is planned for the temporary placement of tailings when rainy field or upset plant conditions prevent the acceptable placement of tailings.

 

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A 2 km long haul road will extend from the existing public road to the facility embankment crest. The haul road is configured to provide containment and act as the downstream retaining embankment for the contact water collection pond. A 2.3 km long facility perimeter access road will run along the facility perimeter to allow access to the facility for operations and maintenance.

The surface water management strategy for the facility is to construct non-contact diversion channels to limit surface water runoff over the tailings and embankment surfaces during the operations and passive closure phases. The primary drainage systems will comprise underliner and overliner drainage systems.

The contact water collection pond will have a minimum storage capacity of 70,000 cubic metres and will be located downstream of the embankment. An emergency spillway is included in the design. The upstream face of the collection pond dam and its pond area will be lined with a composite liner comprising a low permeability subbase overlain by a geomembrane, which will extend to the average maximum monthly pond elevation. Above the maximum monthly pond elevation, the pond will be soil lined. All lined surfaces will be overlain by a protective soil layer and articulated concrete blocks. The water in the collection pond will be pumped to the water treatment plant.

Non-contact stormwater outside of the facility footprint will be routed around the outer perimeter of the facility via two non-contact diversion channels that will discharge downstream of the collection pond to the Suratá River in compliance with the discharge permits. The water diversion channels are designed to divert up-gradient runoff around the facility to limit water from running onto the tailings stack and embankment.

The facility will store filtered tailings from the processing plant and potentially acid generating waste rock from the underground mine. A system of portable conveyors known as grasshoppers will transport the filtered tailings from the filtration plant to the perimeter of the tailings facility, from where they will be loaded in trucks for hauling and deposition to the tailings basin. Truck hauling of the filtered tailings will be utilized when the conveyors are under maintenance.

To support with geotechnical stability and to limit long term settlement of the tailings, the filtered tailings will be placed and compacted. The in place moisture content will likely be less than approximately 14%. The tailings will be placed in horizontal lifts, starting at the upstream toe of the embankment and extending up the valley.

Potentially acid generating waste rock will be hauled to the facility by truck and placed in trenches excavated into the compacted tailings stack, then immediately covered with compacted filtered tailings.

Knight Piésold developed a closure plan to provide a long term solution for a safe, structurally stable, and non-erodible cover for environmental sustainability. The facility closure plan was guided by federal regulations and guidance by the Autoridad Nacional de Licencias Ambientales (National Authority of Environmental Licenses, ANLA), and wherever that guidance was inapplicable, local regulations and or international standards were considered. Chemical and physical stability of the facility will be maintained by careful consideration of directing and managing surface water runoff and by designing a cover system that will effectively control meteoric infiltration into the tailings facility and perform appropriately with little to no maintenance. The tailings basin will be closed by progressively placing a cover system over the tailings as operations proceed. The cover system will comprise an upper revegetated layer or growth media overlying a compacted clay zone which will help prevent wind or water from eroding the tailings and will reduce water infiltration into the tailings.

Knight Piésold developed a closure and post closure monitoring plan consistent with the facility’s current design, including the required geotechnical instrumentation, the installation locations, monitoring, and maintenance.

1.12.5 Water sources and management

The Project has been designed with robust water management and protection as guiding principles. There is sufficient and readily available water within the Project area for all aspects of the operation including mining, processing, the camp, and other activities. Construction water will be sourced under permits from the La Baja Creek and Suratá River, which both have abundant water supply. During operation, the main source of water for the underground mine and its associated infrastructure will be from groundwater and the main source of water for processing will be from the adjacent Suratá River.

The Project plans to reuse, recycle, and return approximately 96.5% of the Project’s total water requirements back to the environment, resulting in a net water use estimated at 3.5%. The majority of the demand will be supplied by the Suratá River, which will supply approximately 2.8 litres per second of net make up water for the processing plant, representing

 

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0.22% of the average flow of the Suratá River at the planned water access point near the village of Suratá, and 0.08% of the average flow of the Suratá River at Bucaramanga, the nearest city located 55 km downstream from the Project.

The Project includes a comprehensive water management plan that incorporates plans and programs tailored to each water application or activity with significant interaction with water to ensure that both the quality and quantity of local water resources are preserved throughout the life of the operation, and all potential impacts related to water use have been thoroughly identified, assessed, and addressed through prevention, mitigation, and compensation measures. The underground mine has been designed to minimize groundwater flows into the underground workings through advanced cover drilling and grouting ahead of mine development to identify and seal any water bearing structures before mining reaches them, greatly reducing potential inflow, and to manage, treat, and if required, safely return any captured water to the environment in compliance with the environmental standards and discharge permits. The process plant has been designed to minimize the use of water and to recycle both process water and the water obtained from the dewatering of the process tailings. The filtered tailings storage facility has been designed to divert rainwater runoff away from the facility and to drain and manage any subsequent dewatering of the tailings and any rainwater falling onto the facility. Continuous monitoring of water flow and quality will be undertaken with defined measures planned if any changes are detected. These strategies will help ensure that the current water flow rates within the ecosystem are maintained.

Water from mine dewatering, seepage collected from the filtered tailings facility, and process water streams will report to water treatment plants where each stream will be treated separately. Treated water from the domestic wastewater and industrial wastewater treatment plants located at the mine will discharge at La Baja Creek, in compliance with the discharge permits. Treated water from the other domestic and industrial wastewater treatment plants will be discharged to the Suratá River, all in compliance with the discharge permits.

Precipitation runoff from clean water areas will be either diverted to the surrounding environment or channeled to a designated location, where it converges with other catchment areas. The collected water will be directed towards the nearest river through controlled drainage pathways, in compliance with the water discharge permits. Grey water run off will be collected separately and diverted to a collection pond. A water treatment plant will then process the water which will then be either pumped to the process plant or safely discharged into the environment in compliance with the water discharge permits.

1.12.6 Power

The estimated power requirements are 13 MW at the process plant and 10 MW at the underground mine, for a total Project requirement of 23 MW. An existing 34.5 kV power line from Bucaramanga supplies a 5 MVA at 34.5 kV capacity substation at the underground mine, which can be used for construction power and as an alternative emergency power source, but is insufficient for operations.

Electrical power to the operations will be supplied from the Palos 115 kV substation in the Bucaramanga area via a 34 km long 115 kV, 45 MVA capacity overhead line leading to a new substation at the process plant, where the voltage will be stepped down to 13.8 kV for reception by the mine’s main distribution substation. The main distribution station will supply power via 13.8 kV cables to the process plant, by 13.8 kV overhead line to the filtered tailings facility and water intake plant, and by a 7 km long 13.8 kV cable installed on the rope conveyor to service the underground operation and the underground substation.

Standby and emergency power supply will be provided by a 3.125 MW diesel generator station at the process plant, a 630 kW diesel generator station at the filtered tailings facility, a 250 kW diesel generator at the water intake plant, a 250 kW diesel generator at the emergency ponds, and by a 2.5 MW diesel generator station at the underground mine.

1.12.7 Environmental factors

The Property is almost entirely located in a mountain ecosystem within a tropical humid climate zone, characterized by forests of medium sized trees of less than 20 m in height. Endemic and conservation status species identified in the Project area of influence include plant species of regional and/or national concern, and six native fish species in the Suratá River. The Project area of potential influence does not contain any sensitive or strategic ecosystems, but it does include priority conservation areas designated by the National Council for Economic and Social Policy. These areas show signs of vegetation degradation and transformation. The majority of the Project is located on land that shows pervasive anthropogenic

 

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alteration over time, and observations of wildlife and aviation fauna are almost non-existent. Upon closure, land reclamation and re-establishment of vegetation and soil profiles are not expected to be a challenge. Outside of the Project area, the most notable strategic ecosystem is the Santurbán páramo. Based on the current delimitation of the Santurbán páramo, the Project footprint is located 600 m horizontally from the Santurbán páramo and approximately 350 m in elevation below it. The Colombian government is still in the process of redefining the Santurbán páramo boundaries, and while these distances may change, the Project is outside of the Santurbán páramo boundaries.

The Project’s planned processing plant, filtered tailings facility, and associated water treatment facilities are located within the La Baja Creek catchment and adjacent minor tributaries of the Suratá River. Larger stream flows are sustained by groundwater discharge and are responsive to rainfall events. Groundwater in the area is complex and influenced by geology and structures.

Numerous environmental and social baseline studies and monitoring programs have been undertaken since 2013 and are ongoing as further information is required to support the Project development plans.

The Project’s attention to reducing the environmental effects of the proposed Project embodies local knowledge and the results of options analyses to find environmentally appropriate and cost-effective solutions to de-risking impacts of the Project. The Project has developed a detailed environmental and social management program to guide the Project’s activities during construction, operation, and closure, consistent with the environmental and social impact assessment (ESIA) process outcome. Each plan has a monitoring component and adaptive management process to evaluate the plan effectiveness and inform updates as required, and reporting requirements to regulators, communities, and stakeholders. The plan components are at various stages of development and will be validated by the community of the area of influence. The components cover topics including biotic and abiotic programs, socioeconomic programs, landscape management and control programs, and an emergency response and readiness plan. Community validation of the programs is ongoing, ensuring local input into final designs.

Colombian law requires that a value of not less than 1% of the value of the Project’s capital expenditure and associated development costs must be invested in environmental and/or sustainability related projects. Funds from the 1% investment plan will be managed by the Corporación Autónoma Regional para la Defensa de la Meseta de Bucaramanga (CDMB) based on the programs jointly identified with PSN. The total capital expenditure associated with the development plan includes expenditures that exceed the 1% requirement.

A mining concession holder is liable for environmental remediation and other penalties that may arise as a result of the concession holder’s actions or omissions occurring after the date the concession contract is awarded. Concession holders are not, however, responsible for environmental liabilities associated with historic artisanal or unauthorized workings. However, the CDMB has requested that the Project address the restoration of certain historic workings. PSN is and will continue to keep working with the regulatory authorities to remediate damage wherever possible.

Water quality within the titles is monitored at points that include areas of historical process plants and artisanal mining tunnels. Historic mines have been sealed off as part of a mine closure program, and there is an ongoing program of disassembling process plants and removing contaminants left behind due to past mining and processing activities. These remediation efforts will continue with the development of the Project.

1.12.8 Permitting factors

The Project holds a mining license granted by the ANM in 2018 and amended in 2021 for mining title 095-68 covering the mineral resources and reserves, the planned underground mining infrastructure, and the surface infrastructure at the mine area. The Project holds the licenses it requires for the current phase of the Project, which authorize occupancy of the land, the use of water for drilling, potable water usage, and water treatment and discharge.

The key permissions required to commence Project construction and operation are the approvals of the ESIA to obtain the environmental license, completion of the resettlement obligations as set forth in the environmental license, and the amendment and approval of the existing approved works and construction program (PTO, the Programa de Trabajo y Obras) to reflect the environmental license conditions.

 

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PSN will submit an updated ESIA to the CDMB, outlining the Project’s description as contemplated in the current prefeasibility study. These changes will require additional studies including a re-evaluation of environmental and social impacts, and restart of the environmental permitting process and timeframes.

Once approved, the environmental license is valid for the life of the Project, subject to compliance audits by the environmental authority. The license may be modified as the Project evolves.

On January 30, 2024, the Colombian Ministry of Environment issued Decree 044 which allows the Ministry to declare temporary reserve areas in certain parts of Colombia. To establish a temporary reserve area, a resolution must be issued by the Ministry detailing the area that is to be temporarily reserved. The Ministry issued Resolution 221 of 2025, amended by Resolution 239 of 2025, by means of which it declared a TRA in the Soto Norte region. The TRA will be in effect for two years, with a possible two year extension. While the TRA is in force, no new concessions or environmental permits may be granted by the mining or environmental regulators. During this period, the Ministry of Environment and Sustainable Development of Colombia must conduct environmental studies to determine whether to make the reserve area permanent. Notwithstanding the TRA, the Soto Norte Project may continue environmental studies, provided no environmental permit is required. Decree 044 and the TRA may delay licencing of the Soto Norte Project.

Decree 044 and the TRA resolutions are presently being challenged in administrative courts, with actions led by the Colombian Disciplinary Office, artisanal and small mining units, the Colombian Mining Trade Association, and the National trade association.

Additionally, the Administrative Tribunal of Santander issued a ruling in July 2025 in a class action proceeding recognizing the Santurbán páramo as a subject of personal rights and designating the Ministry of Environment as its legal guardian. While there is no direct impact on the Soto Norte Project, environmental licensing proceedings for the Soto Norte Project may be delayed or hindered because the Tribunal ordered that: (i) the Ministry of Environment must actively participate and protect the páramo in any licensing process, including through the use of administrative injunctions (ii) all relevant environmental authorities must identify critical transition areas to the páramo in the Soto Norte region for water protection, and (iii) zoning regulations must exclude mining activities in “buffer zones” in alignment with the 2014 delimitation process. The ruling was appealed.

The Soto Norte Project remains several years away from development. With the completion of this technical report, PSN intends to present a fully redesigned project to the Colombian regulators following the conclusion of the environmental and technical studies currently underway.

1.12.9 Social or community factors

Mining was undertaken by the indigenous Sura people in the California – Vetas mining district in Pre-Columbian times and later by the Spanish who produced gold for two and a half centuries, as well as by English and French companies in the early 1800s and 1900s. Colombia continues to have an active artisanal and small-scale mining sector, with traditional miners across the country engaging in small-scale gold extraction, often in remote regions. This sector plays a significant role in local economies and provides livelihoods for many communities.

The municipalities closest to the Project include California, Suratá, and Matanza, which have a combined population of approximately 11,500. The economy of the province of Soto Norte is based on agriculture, mining, and forestry related activities. The economy of California, located closest to the Project, is dominated by artisanal and small scale mining, and the economies of Suratá and Matanza are dominated by ranching, agriculture, and forestry.

The Project is proactively managing the intersection of communities and the Project elements through its community engagement model. In 2023, the Project launched a new strategy to implement best practices in community engagement across the Soto Norte region. The Project team and community leaders and authorities have collaborated to develop social agreements that enable the joint identification of needs and the evaluation of solutions in a coordinated and structured manner. This enables a shared understanding of the Project’s role in driving sustainable development in the region and empowers the communities to decide on resource allocation and to propose projects, initiatives, or services to improve their quality of life. Each shared initiative is designed to prevent and mitigate potential disruptions to the Project’s operations, facilitate the acquisition of the necessary permits for land access to ensure the completion of required studies,

 

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foster a favourable socio-political environment in the area of influence, supporting the Project’s milestones, streamlining the permitting process, and to effectively address environmental challenges.

The community widely regards the Project social agreement as a successful model, and is celebrated for its accomplishments in implementing projects and programs that have positively impacted local communities. The model has achieved community integration, effective collaboration between leaders and residents, community empowerment, and accountability for outcomes through collective efforts. The agreements play a vital role in strengthening relationships by encouraging their members to advocate for the Project within the broader community, and ensure a closer and more effective dialogue channel, enhance positive perceptions of the Project, and foster stakeholder trust, all of which are critical elements in de-risking social support for the Project and instilling confidence in the Project’s success.

The strategic engagement model includes the social agreement commissions, a sponsorship plan, social houses, information and socialization forums to deliver timely and transparent information about the Project’s operations and activities, and regional and national engagement beyond the area of influence. The sponsorship plan involves assigning Project social team members to specific villages and sectors within the communities of California and Suratá to maintain systematic engagement with families and local leaders, to foster a deeper understanding of the communities, address concerns, gather valuable ideas, and counter misinformation and mitigating factors that could impact social management and the Project’s reputation. The social houses in California, Suratá, and Matanza have become central hubs for activities and meeting points, and serve as the primary platform for receiving community requests.

Development of the Project involving the municipalities of California, Suratá, and Matanza will provide a diversity of employment and socioeconomic opportunities to residents. The Project will require skilled mine workers, services, material suppliers, contractors, housing, health, education, and skills training. Collaboration with contract mining partners is an integral component of the Project development. The direct income benefits of the Project will result in opportunities for indirect benefits such as support to local business, career opportunities for young adults, investment in non-mining related enterprises, and traditional agricultural, cultural, and artisan pursuits.

The Project currently employs 53 people, of whom 40 are from local communities and 25 are female. The peak workforce during Project construction is estimated at 2,292, mainly comprised of contractors, plus 90 administrative staff and management. During operations the workforce is estimated at 676 company personnel. The Project is targeting 60% of the workforce to be hired from the local community, 20% from the department of Santander, and 18% from other departments in Colombia. Foreign technical and managerial specialists will eventually make up 2% of the workforce. The socioeconomic benefits of the Project will also affect the broader region including the city of Bucaramanga for employees, suppliers, and contractors.

Aris Mining collaborates with small-scale miners, known as contract mining partners, to create mutually beneficial partnerships that support the host communities. This partnership model includes the formation of formal companies that employ between 25 and 500 people as well as mill feed agreements such as those at Aris Mining’s Segovia and Marmato mines that comprise long term contracts to supply mill feed for Aris Mining’s processing plants, with payments based on gold content, grade, and the spot gold price. These agreements provide the contract mining partners with access to Aris Mining’s technical, operational, and safety expertise as well as working capital financing. Aris Mining provides training programs in health and safety, environmental stewardship, accounting, compliance, and business management. Other benefits for the contract mining partners include access to social security and legal protections, government benefits, financial services, and broader market opportunities.

A suitable area within the Project titles was identified for the contract mining partners and in 2021 PSN entered into a four year subcontract with a group of small scale miners known as Calimineros S.A.S. to perform small mining activities covering 0.51 ha within title 125-68, which is located on the eastern boundary of the main 095-68 title. The Calimineros project and its mining plan were approved by the National Mining Authority, and Calimineros submitted a request to obtain an environmental license, and the approval process is pending. An extension of the subcontract was submitted to the National Mining Authority in the second quarter of 2025.

Additional land acquisition required for the construction and operation of the Project will result in resettlement for some members of the surrounding communities. Based on the Project footprint, 108 properties have been identified that will require either acquisition or an easement, provisionally affecting 198 households. Relocation areas to enable continuity of livelihoods are under evaluation. Where easement cannot be agreed upon, they may be imposed by judicial order. If

 

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purchase agreements cannot be mutually agreed, expropriation authorization must be obtained from the National Mining Agency prior to starting the expropriation proceedings. The preferred method for acquiring land at Soto Norte for project development will be to reach agreements with landowners following receipt of the environmental permits

Resettlement has been identified as the most significant impact of the Project and therefore is a key focus of the management programs. A draft resettlement action plan (RAP) has been developed to guide the resettlement process. The RAP will be implemented in compliance with Colombian regulations, subject to approval by the environmental authority, will only commence following issuance of the Project’s environmental license.

To mitigate risks of delay to the construction schedule, the Project has developed strategies to work collaboratively with affected households during the land acquisition and resettlement process.

1.13 Capital and operating costs

1.13.1 Capital cost estimates

The capital cost estimates have an accuracy of +/-25%, suitable for the prefeasibility study level. A summary of the estimated initial capital expenditures, including any operating costs incurred during the pre-production period, is shown in Table 1-3 and a summary of the estimated deferred and sustaining capital costs are shown in Table 1-4.

Table 1-3   Estimated initial capital costs

 

Initial capital expenditure		Amount ($M)
Mining
Mobile equipment		24.2
Fixed equipment		10.3
Lateral development		10.4
Vertical development		0.8
Pre-production operating costs and first fills		9.8
Mining total		55.5
Surface
Infrastructure		172.4
Rope conveyor		74.8
Process plant		95.7
Owner’s, indirects, and first fills		21.5
Engineering, procurement, and construction management (EPCM)		35.4
Replacement capital		-
Surface total		399.8
Other costs
Resettlement and environmental monitoring		72.8
Electricity supply down payment		0.2
Other start-up costs		8.8
Capitalized VAT		34.2
Contingency		54.0
Other Costs Total		170.0
Total		625.2

 

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Table 1-4   Estimated deferred and sustaining capital costs

 

Deferred and sustaining capital expenditure		Amount ($M)
Mobile equipment			138.0
Fixed equipment			68.1
Lateral development			117.5
Vertical development			31.2
EPCM			3.6
Replacement costs			4.2
Other costs			1.1
Total			363.6

1.13.2 Operating cost estimates

The life of mine operating costs, excluding capitalized operating costs, were estimated for underground mining, surface including processing and the rope conveyor, G&A including other costs, realization, and royalties. Royalties due to the Colombian state include a 4% royalty on 80% of the gold and silver produced and a 5% royalty for copper on 100% of the copper produced. The summary of the estimated life of mine operating costs is shown Table 1-5 and the estimated life of mine unit operating cost estimate is shown in Table 1-6.

Table 1-5   Estimated operating costs

 

Item		Total life of mine ($M)				Pre-production ($M)				Production ($M)				Post-production ($M)
Mining
G&A			9.3				0.1				9.2				-
Contracts			21.6				0.4				21.1				-
Mine labour			62.8				0.4				62.4				-
Equipment maintenance and operation			236.2				1.4				234.8				-
Power			125.9				0.3				125.7				-
Diesel			36.5				0.2				36.2				-
Explosives			32.8				0.1				32.7				-
Ground support			266.6				1.4				265.2				-
Drilling consumables			48.0				0.3				47.6				-
Mine services			25.1				0.2				25.0				-
First fills			4.9				4.9				-				-
Mining total			869.6				9.8				859.8				-
Processing and surface
Labour			94.8				-				94.8				-
Reagents			47.3				-				47.3				-
Power			214.8				-				214.8				-
Plant maintenance			49.3				-				49.3				-
Rope conveyor			10.1				-				10.1				-
Plant consumables			8.3				-				8.3				-
Processing and surface total			424.7				-				424.7				-
Realization
Treatment charges			17.0				-				17.0				-
Refining charges			47.5				-				47.5				-
Penalties			81.8				-				81.8				-

 

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Item		Total life of mine ($M)				Pre-production ($M)				Production ($M)				Post-production ($M)
Freight			244.0				-				244.0				-
Realization total			390.3				-				390.3				-
Mine site G&A			395.1				8.8				386.3				-
Environmental management plan			69.8				18.1				42.2				9.6
Royalties			393.3				-				393.3				-
Total			2,542.8				36.7				2,496.5				9.6

Table 1-6  Estimated life of mine unit operating costs

 

Unit operating costs			Life of mine $/t ore
Mining			41.70
Processing			20.59
Other (G&A, environmental management plan, etc)			21.24
Treatment, refining, and shipping			18.93
Royalties			19.07
Total			121.54

1.14  Economic analysis

This economic analysis was undertaken to assess and confirm the current mineral reserve estimate disclosed in this technical report, utilizing the production schedule and the capital and operating cost estimates. The economic analysis has been conducted on a post-tax, 100% equity (i.e., no debt financing) basis, in constant dollar terms. Sunk costs, such as exploration and the cost of previous studies, were excluded from the analysis.

The economic viability of the mineral reserves has been evaluated using key economic indicators, including annual and cumulative cash flows, NPV, and IRR. The NPV presented in this technical report should not be interpreted as the definitive value of the Project and must be considered in conjunction with the accompanying sensitivity analysis.

The economic analysis incorporates a statutory corporate income tax rate of 35%. The key economic results are presented on a pre-tax basis to facilitate comparison with other projects in different jurisdictions by removing the effect of local tax regimes, and on an after-tax basis incorporating the applicable tax rates and fiscal terms for the Project, providing a more accurate reflection of the potential economic benefit to the Project owners.

The processing facility has been designed with a 3,500 tpd capacity, but the Project underground mining production schedule has been constrained to 2,750 tpd with the additional 750 tpd dedicated for potential mill feed purchases from contract mining partners. The financial projections in this technical report do not account for revenue, operating costs, or profit margins from the dedicated capacity.

The construction period is scheduled for 13 quarters (3.25 years). The first underground ore production from development activities is planned during the final six months of Project construction, with all material stockpiled until the process plant is commissioned. The pre-production stockpile is scheduled to supplement run of mine ore feed during the first six months of Year 1, supporting the production ramp up.

Plant throughput will ramp up progressively to the 2,750 tpd capacity, reaching steady state operations toward the end of Year 2. Based on the current mineral reserve estimate, the mine life extends to Year 22.

The total life of mine production is shown in Table 1-7 and the total life of mine concentrate production is shown in Table 1-8.

 

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Table 1-7  Total life of mine production

 

Mining		Units		Total
Waste		kt		5,380
Development ore		kt		3,501
Stope ore		kt		17,119
Total material mined		kt		26,000
Mined gold grade		g/t Au		6.98
Mined silver grade		g/t Ag		32.0
Mined copper grade		% Cu		0.20
Contained mined gold		koz		4,627
Contained mined silver		koz		21,216
Contained mined copper		Mlb		90.6

Table 1-8  Total life of mine concentrate production

 

Concentrates		Units		Copper concentrates		Pyrite concentrates		Gravity gold concentrates		Total
Mass		DMT1		169,184		1,441,402		615			1,611,201
Contained metal in concentrates
Gold		koz		2,092		2,103		105			4,299
Silver		koz		9,305		9,529		1			18,834
Copper		Mlb		67.4		16.6		Nil			84.0
Concentrate grade
Gold		g/t		385		45		5,307
Silver		g/t		1,711		206		32
Copper		%		18		0.52		Nil
Note 1. Dry metric tonnes

The financial analysis utilized the following metal price assumptions for the base case:

 

•

Gold: $2,600/oz

•

Silver: $29/oz

•

Copper: $4.30/lb

These metal prices were selected as being in line with the median of the long term forecasts of a group of banks and financial institutions, as at the end of August 2025.

The results of the economic analysis are summarized in Table 1-9. The economic analysis excludes any contribution from the 750 tpd processing capacity dedicated for contract mining partners, which is intended to support regional formalization initiatives and environmental improvements. The NPV at a range of discount rates is shown in Table 1-10.

Table 1-9  Soto Norte economic evaluation results

 

Key indicators		Units				Total
Total gold in concentrates life of mine			koz				4,299
Initial life of mine at an owner-mining rate of 2,750 tpd			Years				22
Average annual gold production (years 2 to 10)			koz				263
Average annual gold production (years 1 to 21)			koz				203
Life of mine average cash cost			$/oz Au				345
Life of mine average all in sustaining cost			$/oz Au				534

 

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Key indicators		Units				Total
Average EBITDA (years 2 to 10)			$M				547
Average annual EBITDA (years 1 to 21)			$M				410
Summary cash flow for the life of mine ($M) at $2,600/oz gold price
Revenue from payable gold sales							10,403
Less: royalties							393
Less: operating costs, net of by-product silver and copper							1,381
Less: sustaining capital							364
Operating margin							8,265
Less: income tax							2,630
After-tax cash flow							5,635
Less initial capital including pre-production costs, VAT, and contingency							625
Less: closure costs							25
Net cash flow							4,985
Pre-tax indicators at $2,600/oz gold price
NPV at 5% discount rate			$M				4,203
IRR			%				45.8
Payback period (from start of operations)			Years				1.9
After-tax indicators at $2,600 gold price
NPV at 5% discount rate			$M				2,680
IRR			%				35.4
Payback period (from start of operations)			Years				2.3
After-tax indicators at $3,200/oz gold price
NPV at 5% discount rate			$M				3,559
IRR			%				42.1
Payback period (from start of operations)			Years				2.0

Table 1-10  Sensitivity of NPV to discount rate

 

Discount rate		Units		Pre-tax NPV		After-tax NPV
0.0%		$M		7,615		4,985
5.0% (base case)		$M		4,203		2,680
10.0%		$M		2,481		1,519

The sensitivity of the after-tax NPV_5%, after-tax IRR, and after-tax payback period to a range of gold prices is shown in Table 1-11.

Table 1-11  Sensitivity of key economic indicators to gold price

 

Gold price		$2,000/oz				$2,200/oz				$2,400/oz				$2,600/oz Base case				$2,800/oz				$3,000/oz				$3,200/oz
Indicator
After-tax NPV5% ($M)			1,800				2,093				2,387				2,680				2,973				3,266				3,559
After-tax IRR (%)			27.7				30.4				33.0				35.4				37.8				40.0				42.1
Payback period (years)			2.8				2.6				2.5				2.3				2.2				2.1				2.0

 

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