St. Augustine Announces Positive Results of the Kingking Copper-Gold Project Updated Preliminary Feasibility Study NPV7% of $4.18 Billion After-tax IRR of 34.2% at $4.30/lb Copper / $2,150 Gold 1.9 year Payback of Initial Capital Costs

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July 31, 2025

St. Augustine Announces Positive Results of the

Kingking Copper-Gold Project Updated Preliminary

Feasibility Study

NPV7% of $4.18 Billion

After-tax IRR of 34.2% at $4.30/lb Copper / $2,150 Gold

1.9 year Payback of Initial Capital Costs

Initial Capital Estimate of $2.37 Billion

After-tax Benefit Cost Ratio of 1.8

Reserve Estimate of 960 million Tonnes

849 million Tonnes of Proven and Probable Milling Reserves

and 111 million Tonnes of Proven and Probable Leaching

Reserves

Material Regulatory Approvals in Place

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Equivalent Mill Copper Grade of 0.83% for the First Five

Years of Milling and 0.58% for the First Twenty Years of

Milling

Payable Copper and Gold Production is Estimated to be 4.4

billion Pounds (2.0 million tonnes) and 6.9 million ounces

(214,000 kilograms) over a 38-Year Mine/Process Life, with

Cash Costs of $2.06 per Equivalent Pound of Copper and C1

Cash Costs of $0.32 per Pound of Copper Net of Gold Credits

Annual Production Average in the first 5 years will be 284

million Pounds (129,000 tonnes) of Payable Copper in cathode

and concentrate and 333,000 Ounces (10,340 kilograms) of

Payable Gold in Concentrate and Doré metal.

Total MPSA Tenement and Land Area St. Augustine Controls

for Development has been increased from 1,656 Hectares to

Greater than 2,976 Hectares.

Planned Tradeoff and Optimization Studies Focus on Chloride

Leach to support Low Grade Sulfide Stockpile Copper

production at the beginning of mine life / Improved Mill

Recoveries / Improved Crushing and Grinding Circuit

efficiency for levelized mill throughput at total plant capacity

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St. Augustine plans to move the large scale open pit Kingking

project through Definitive Feasibility and into production on

an optimized schedule.

Manila, Philippines, July 31, 2025 – St. Augustine Gold and Copper Limited (TSX:SAU) (“St.

Augustine” or the “Company”) is pleased to announce the results of the updated Preliminary

Feasibility Study (“PFS”) of the Kingking Copper-Gold Project located in Pantukan, Davao de Oro,

Philippines. The updated Pre-Feasibility Study allows the Company to initiate work on the Definitive

Feasibility Study and expedite the start of construction. The results of the PFS demonstrate extremely

robust economics, generating an estimated post-tax net present value ("NPV") of $4.18 billion and

internal rate of return ("IRR") of 34.2%. The benefit-cost ratio (BCR) is 1.81

The Company’s senior management team led by Mr. Michael G. Regino, Chief Operating

Officer, Mr. Andrew J. Russell, Project Director, and Mr. Nico Paraskevas, Executive Director,

completed the effort over the last 14 months.

Mr. Regino commented: “The update to the Pre-Feasibility Study for Kingking is a long-awaited

milestone for our shareholders, especially in the context of recent changes to the Philippine

mining regulatory structure which have paved the way for a world class project development.

The benefit of the project to the Philippine economy as well as the local communities cannot be

overstated. The location in Southeast Asia is enviable with direct ship access to the largest

copper market on earth. We look forward to participating in these critical metals supply

chains.”

Mr. Regino further stated: “The first 5 years of Kingking gold production will make it one of

the top 25 worldwide gold producers at more than 333,000 oz per year, excluding its substantial

copper production. The combined copper and gold production brings Kingking into the top 10

copper producing mines on a copper equivalent basis at more than 204,000 equivalent tonnes

per year.”

The Company believes that following completion of the update to the PFS, the opportunity to

move the Kingking project through the Definitive Feasibility process and into production can

soon be realized. Mr. Russell noted “This project will produce copper net of by-product credits

at one of the lowest rates of any operation worldwide. The tradeoff studies and recommendations

provide a clear path to improved efficiencies, levelized production, and operational excellence.

We have some of the world’s best engineering firms supporting us in this endeavor.”

Mr. Paraskevas further stated: “Open pit mining projects of the scale of Kingking are rare, and

1 The benefit cost ratio (BCR) is calculated by dividing the after-tax net present value (at 7% discount) of $4.18 billion by

the initial capital cost plus sustaining capital cost (at 7% discount) of $2.28 billion.

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even more so considering that the Kingking project has substantially completed applicable

permitting requirements and is essentially shovel ready. We are very pleased with the results of

the Preliminary Feasibility Study, which confirm the strong technical and economic potential of

our Kingking project. These results reinforce our confidence in delivering value to our

stakeholders and further demonstrate the significant opportunity that Kingking represents for

the region and our shareholders. We look forward to advancing the project towards a definitive

feasibility study and continuing our engagement with stakeholders and partners as we progress.”

Permitting Status

The Environmental Impact Statement (EIS) and Declaration of Mine Project Feasibility

(“DMPF”) were submitted to the Philippine Government in 2012. The Environmental

Compliance Certificate (ECC) was granted in February 2015 (EIS approval) and Declaration of

Mining Project Feasibility (DMPF) was approved in January 2016. The Company has

confirmed with the Mines and Geosciences Bureau (MGB) and Environmental Management

Bureau (EMB) that the DMPF and ECC are in good standing. Additionally, as required by the

EMB, the Company has secured ISO 14001: 2015 Certification for Environmental Management

System (EMS) in 2018, which remains valid. The Mineral Processing Permit (MPP) is currently

lapsed because of the Company’s inability to proceed to the development of the Kingking Project

due to a combination of regulatory restrictions, including the 2017 open pit mining ban which

was only lifted in late December 2021, and the operational disruptions caused by the COVID-19

pandemic. These unforeseen events significantly delayed the commencement of the Kingking

Project. The Company is now actively working to complete the requirements to secure the

renewal of its MPP.

Key Project Indicators for the First 23 years of Project Life are illustrated below: Mine

development and construction start in Year 1 and continues into Year 2 with some heap leach

ore stockpiled. Heap Leach and SX-EW construction complete in Year 2 and SX-EW cathode

is produced in Year 3. Mill construction is completed in Year 3, and copper-gold concentrate is

produced in Year 4. Gold Doré bars from gravity concentrate are produced starting in Year 4.

Average annual production during the first five years is projected at 284 million pounds (129,000

tonnes) of payable copper—produced as cathode and concentrate—and 333,000 ounces (10,340

kilograms) of payable gold in concentrate and doré. All cathode production is 100% payable, while

copper concentrate payability is subject to standard market smelter terms, typically ranging from

96.5% to 98%, which have already been factored into the project valuation.

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Figure 1 – Annual Mining of Ore and Waste, LOM W:O Ratio 0.87.2

2 The LOM waste to ore ratio is from the IMC mine schedule file dated December 23, 2023.

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Figure 2 – Annual Mill Equivalent Copper Ore Grade, 0.83% for First 5-Years3

3 The equivalent copper grade is the weighted average over the first five years of mill operations, accounting for copper in

concentrate, tailings leach cathode, and copper equivalent from gold in concentrate and bullion. It is calculated by dividing

the total equivalent copper (in tonnes) by the total ore treated.

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Figure 3 – Annual Equivalent Pounds of Payable Cu, Averages 436 million lbs. for Years 4-84

4 The figure represents the average equivalent payable copper produced over Years 3 to 8, including Heap Leach cathode

from Year 3, divided by 5. Excluding the Year 3 Heap Leach cathode results in a weighted average of 427,835 klb/year.

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Figure 4 – Annual C1 Costs, USD (2024 figures) per Pound of Equivalent Payable Copper5

Figure 5 – Cumulative, by year, Net Present Value at 7% Discount Rate, Shows Rapid Project

Payback

5 These costs include the following: concentrate shipping, smelting and refining; cathode shipping; gold shipping and

refining, mine site operating costs.