Seabridge Gold Provides Updated Mineral Resource Estimates for KSM Project

Press Release

Toronto, Ontario–( – March 31, 2026) – Seabridge Gold Inc. (TSX: SEA) (NYSE: SA) (“Seabridge”) announced today updated Mineral Resource Estimates for its KSM Project located in northwestern British Columbia using metal prices of US$2,000/oz Au, US$4.00/lb Cu, US$25/oz Ag, and US$ 22/lb Mo at a currency exchange rate of 0.746 US$ per 1.00 Cdn$. For the past 10 years, KSM resource disclosure used metal prices of US$1,300/oz Au, US$3.00/lb Cu, US$20/oz Ag, US$9.70/lb Mo at a currency exchange rate of 0.83 US$ per 1.00 Cdn$.

Measured and Indicated Mineral Resources increase by 6.8 million ounces of gold, 1.5 billion pounds of copper, 42.7 million ounces of silver and 93 million pounds of molybdenum compared to the last resource update in January 2024.

Inferred Mineral Resources increase by 12.9 million ounces of gold, 4.2 billion pounds of copper, 108.8 million ounces of silver and 140 million pounds of molybdenum compared to the last resource update in January 2024.

The mineral resource model has not changed, only the assumed metal prices and costs used to constrain the mineral resources and calculate cut-offs. The only difference is the tabulation of the resource blocks above updated cut-offs and inside updated constraining mining shapes. The updated mineral resource tabulation uses the same grade models used in the KSM Preliminary Feasibility Study and Preliminary Economic Assessment, NI 43-101 Technical Report”, with an effective date of August 8, 2022 (see 2022 KSM TECHNICAL REPORT).

Seabridge Chair and CEO Rudi Fronk said the resource restatements reflect gains from the application of updated metal price parameters and operating costs. “As we move towards a joint venture on KSM, our resource estimates’ price assumptions are now consistent with most Tier 1 mining company disclosure.”

The updated Mineral Resource Estimates for KSM are as follows:

Measured Resources
Deposit	Tonnes (000)	Gold		Copper		Silver		Molybdenum
		Grade (g/t)	Ounces (millions)	Grade (%)	Pounds (millions)	Grade (g/t)	Ounces (millions)	Grade (ppm)	Pounds (millions)
Mitchell – OP	700,000	0.67	15.1	0.19	2,932	3.26	73.4	52	80
East Mitchell – OP	1,105,000	0.62	22.0	0.11	2,680	1.78	63.2	86	210
Total Measured	1,805,000	0.64	37.1	0.14	5,612	2.35	136.6	73	290
Indicated Resources
Deposit	Tonnes (000)	Gold		Copper		Silver		Molybdenum
		Grade (g/t)	Ounces (millions)	Grade (%)	Pounds (millions)	Grade (g/t)	Ounces (millions)	Grade (ppm)	Pounds (millions)
Mitchell – OP	1,922,000	0.46	28.4	0.13	5,508	2.7	166.8	65	274
East Mitchell – OP	1,069,000	0.36	12.4	0.08	1,885	1.5	52.9	73	172
Sulphurets – OP	477,000	0.53	8.1	0.20	2,103	1.0	15.3	50	53
Kerr – OP	396,000	0.21	2.7	0.38	3,318	1.1	14	4	4
Kerr – UG	31,000	0.21	0.2	0.40	273	1.5	1.5	12	1
Iron Cap – UG	555,000	0.37	6.6	0.20	2,447	4.1	72.8	35	43
Total Indicated	4,450,000	0.41	58.4	0.16	15,534	2.3	323.3	56	547
Measured plus Indicated Resources
Deposit	Tonnes (000)	Gold		Copper		Silver		Molybdenum
		Grade (g/t)	Ounces (millions)	Grade (%)	Pounds (millions)	Grade (g/t)	Ounces (millions)	Grade (ppm)	Pounds (millions)
Mitchell – OP	2,622,000	0.52	43.5	0.15	8,440	2.8	240.2	61	354
East Mitchell – OP	2,174,000	0.49	34.4	0.10	4,565	1.7	116.1	80	382
Sulphurets – OP	477,000	0.53	8.1	0.20	2,103	1.0	15.3	50	53
Kerr – OP	396,000	0.21	2.7	0.38	3,318	1.1	14.0	4	4
Kerr – UG	31,000	0.21	0.2	0.40	273	1.5	1.5	12	1
Iron Cap – UG	555,000	0.37	6.6	0.2	2,447	4.1	72.8	35	43
Total Measured + Indicated	6,255,000	0.48	95.5	0.15	21,146	2.3	459.9	61	837
Inferred Resources
Deposit	Tonnes (000)	Gold		Copper		Silver		Molybdenum
		Grade (g/t)	Ounces (millions)	Grade (%)	Pounds (millions)	Grade (g/t)	Ounces (millions)	Grade (ppm)	Pounds (millions)
Mitchell – OP	1,980,000	0.26	16.6	0.12	5,238	2.36	150.2	45.8	200
East Mitchell – OP	589,000	0.30	5.7	0.06	779	1.83	34.7	58.1	75
Sulphurets – OP	326,000	0.39	4.1	0.11	791	1.35	14.1	26.0	19
Kerr – OP	106,000	0.24	0.8	0.18	421	1.07	3.6	4.9	1
Kerr – UG	2,699,000	0.27	23.4	0.34	20,231	1.7	147.5	21.1	126
Iron Cap – UG	2,769,000	0.38	33.8	0.25	15,262	2.47	219.9	30.3	185
Total Inferred	8,469,000	0.31	84.4	0.23	42,722	2.1	570	32.5	606
Notes: The effective date for the Mineral Resource Estimate for KSM is March 30, 2026. The Mineral Resource Estimates have been verified and endorsed by Henry Kim P.Geo., an independent Qualified Person. Mineral Resources are reported inclusive of those Mineral Resources that were converted to Mineral Reserves. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Mineral Resources were prepared in accordance with CIM Definition Standards for Mineral Resources and Mineral Reserves (May 10, 2014) and CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines (Nov 29, 2019). Mineral Resources were constrained within mineable shapes depending on the assumed mining methods. Net Smelter Return (NSR) cut-off is $11.85/t for the Mitchell Pit, $12.35/t for the East Mitchell Pit, $9.90/t for the Sulphurets pit, $9.90/t for the Kerr open pit based on updated operating cost and using the following assumptions: metal prices of US$2,000/oz Au, US$4.00/lb Cu, US$25/oz Ag, and US$ 22/lb Mo at a currency exchange rate of 0.746 US$ per 1.00 Cdn$; Copper concentrate terms are 96% payable Cu; 97.8% payable Au; 90% payable Ag. Offsite costs (smelting, refining, transport, and insurance) are $222 per tonne of concentrate; doré terms are $2/oz Au offsite costs (refining, transport and insurance), 99.8% Au payable, and 90% Ag payable; metallurgical recovery projections vary depending on metallurgical domain and metal grades and are based on metallurgical test work. The Mineral Resources have been constrained by “reasonable prospects of eventual economic extraction” mining shapes using assumptions: metal prices of US$2800/oz Au, US$5.6/lb Cu, US$35/oz Ag, and US$ 30.8/lb Mo with a currency exchange rate of 0.746 US$ per 1.00 Cdn$; Pit slopes range between 32-51 degrees in the Mitchell area and 25-43 degrees in the East Mitchell area; with $2.50/t mining costs; $11.85/t process + G&A costs for Mitchell; $12.35/t process + G&A costs for East Mitchell; offsite terms and metallurgical recoveries are the same as Note 7; Pit slopes for Sulphurets range between 34-50 degrees; $2.50/t pit mining costs; $9.90/t process + G&A costs; offsite costs (smelting, refining, transport, and insurance) are $222 per tonne of concentrate; doré terms are $2/oz Au offsite costs (refining, transport and insurance), 99.8% Au payable, 90% Ag payable, 99% Mo payable; Recoveries vary depending on metallurgical domain and metal grades and are based on metallurgical test work as described in Section 13 of the 2022 NI 43-101 report. The block cave constraining shapes for Kerr and Iron Cap were developed by applying an NSR shut-off at the draw point of $18.50/t for Iron Cap and $20.00/t for Kerr. “Moly” = “Molybdenum” Numbers may not add due to rounding.

The mineral resource model has not changed, only the assumed metal prices and costs used to constrain the mineral resources and to calculate the cut-off grade. The updated mineral resource does not materially change the existing mineral reserves because the constraining mining shapes for the mineral reserves are interior to the mining surfaces used for the mineral resources. Also, the cut-offs applied to the Mineral Reserves are higher than those applied to the Mineral Resources.

The change to the Mineral Resources are not considered material to the KSM Project or to Seabridge.

Qualified Persons

Henry Kim P.Geo., the independent Qualified Person and Principal Resource Geologist with Wood Canada Limited, has reviewed and approved the scientific and technical information contained in this press release. Details of the data verification performed to support the Mineral Resource estimates, and identification of any known legal, political, environmental, or other risks that could materially affect the potential development of the mineral resources are provided in Technical Report dated August 8, 2022.

About Seabridge Gold

Seabridge holds a 100% interest in several North American gold projects. Seabridge’s principal asset, the KSM project, and its Iskut projects are located in Northwest British Columbia, Canada’s “Golden Triangle”, the Courageous Lake project is in Canada’s Northwest Territories, the Snowstorm project in the Getchell Gold Belt of Northern Nevada, and the 3 Aces project is in the Yukon Territory. For a full breakdown of Seabridge’s Mineral Reserves and Mineral Resources by category please visit Seabridge’s website at http://www.seabridgegold.com.

None of the Toronto Stock Exchange, the New York Stock Exchange, nor their Regulation Services Providers accepts responsibility for the adequacy or accuracy of this release.

For further information please contact:
Rudi P. Fronk, Chair and C.E.O.
Tel: (416) 367-9292 • Fax: (416) 367-2711
Email: info@seabridgegold.com

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