Mr. Randy Reichert reports

SKEENA INCREASES ESKAY CREEK RESOURCE TO 5.9 MOZ AUEQ IN MEASURED AND INDICATED CATEGORIES

Skeena Resources Ltd. has released an updated mineral resource estimate (MRE) for the 100-per-cent-owned Eskay Creek gold-silver project located in the Golden Triangle of British Columbia. Effective June 20, 2023, the updated MRE incorporates an additional 278 drill holes totalling 67,885 metres, enhancements to the resource estimation methods and updated metallurgical process recoveries.

2023 Eskay Creek MRE highlights:

• Total pit constrained measured and indicated resource of 5.6 million ounces (Moz) at 3.47 grams per tonne gold equivalent (AuEq), including 4.1 Moz at 2.57 g/t Au and 102.5 Moz Ag at 63.63 g/t Ag.
• The pit constrained measured and indicated resource has increased by 430,000 oz AuEq, representing a growth of 8 per cent.
• Measured category AuEq resource increased by 23 per cent and now accounts for 73 per cent of the total pit constrained MRE, up from 63 per cent in the previous estimate.
• MRE reported using conservative commodity prices of $1,700 (U.S.)/oz Au and $23 (U.S.)/oz Ag.
• Metallurgical process recoveries applied to resource are 84 per cent Au and 88 per cent Ag.

Skeena's senior vice-president of exploration and resource development, Paul Geddes, commented: "Considerable analysis was undertaken during this MRE, which includes a new methodology for restricting the influence of high-grade mineralization proximal to formerly mined areas, optimization of block sizes for mining selectivity and added conservatism with process recoveries derived from the 2022 FS. The exploratory and delineation drilling performed in 2022 surrounding the new 23 and 21A West zones has resulted in a positive return on investment."

Randy Reichert, Skeena's president and chief executive officer, goes on to comment: "With the outcome of an additional 432,000 gold equivalent ounces, we are very pleased with the continued resource growth at Eskay Creek. We successfully converted a significant amount of indicated resources to the measured category, increasing our confidence in the deposit. Given most of the resources included in this update are within the measured and indicated categories we expect a large percentage to convert to reserves, potentially adding a year or more of mine life to the Q4 2023 definitive feasibility study."

Pit constrained resource discussion

The 2023 MRE pit parameters used to determine resources with reasonable prospects for eventual economic extraction are analogous to those used for the 2022 MRE apart from the updated metallurgical process recoveries of 84 per cent gold and 88 per cent silver which informed the 2022 feasibility study. The differential in assumed process recoveries resulted in the shallowing of the resource reporting pit in certain areas relative to the 2022 MRE. Conversely, the 2022 drilling programs in the 23 and 21A West zones generated new resources which resulted in pit expansions.

Underground constrained resource

No material change has occurred in the reported underground resources. Variation in remnant tonnages relative to the 2022 MRE is largely due to the new 2023 pit geometry and the one-metre geotechnical buffer around the underground workings being removed due to the selective nature of the drift and fill mining method. The current MRE for underground resources is proximal to the planned pit. The company's 2022 drilling in the Eskay Deeps discovery has not yet affected the underground constrained resource due to the widely spaced nature of the two drill holes.

Modification to block size

The 2023 MRE now applies a regular block size of five by five by 2.5 metres (XYZ) to better inform future economic analyses that will contemplate more selective mining. This will also be incorporated into the definitive feasibility study (DFS) with 10-metre benches split with three dig flitches per bench and smaller backhoe excavators. The 2022 pit constrained MRE utilized 10-by-10-by-five-metre parent blocks with five-by-five-by-2.5-metre subblocks which are not as well suited for engineering the more selective mining.

High-grade restriction buffer surrounding historical stopes

In the 2022 MRE, a one-metre buffer enveloping the underground stopes was used to constrain and restrict the influence of the previously mined extremely high-grade drill hole samples. The 2023 model now applies 15 g/t AuEq cut-off grade shells modelled in the orientation of the contact mudstone to constrain and restrict the influence of the extremely high grades. This methodology forms a more geologically based domain, as opposed to only utilizing the historical underground excavations.

Application of dynamic anisotropy

The NEX and HW zones were estimated in Skeena's 2022 model using the single-search ellipsoid of the variogram. In the updated 2023 model, dynamic anisotropy, which adjusts for the folded orientation of the search ellipse on a block-by-block basis, was employed using the orientation of the contact mudstone as a guide. When compared with the 2022 MRE, the use of dynamic anisotropy results in a more robust estimation.

Resource model reconciliation

As a test to determine the accuracy of the new model, an internal reconciliation study of the historically mined portion of the 2023 MRE demonstrates that with the updated resource methodology, the grades more closely resemble the gold and silver grades of the reported historical mine production relative to the 2022 model. This improved reconciliation adds additional confidence to the methodologies and optimizations applied to the 2023 MRE.

Eskay Creek 2023 MRE notes

The mineral resources disclosed in this press release were estimated using the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) standards on mineral resources and reserves definitions, and guidelines prepared by the CIM standing committee on reserve definition and adopted by the CIM council.

About Skeena Resources Ltd.

Skeena Resources is a Canadian mining exploration and development company focused on revitalizing the past-producing Eskay Creek gold-silver mine located in Tahltan territory in the Golden Triangle of northwest British Columbia, Canada. The company released a feasibility study for Eskay Creek in September, 2022, which highlights an after-tax net present value (5 per cent) of $1.4-billion, 50-per-cent internal rate of return, and a one-year payback at $1,700 (U.S.)/oz Au and $19 (U.S.)/oz Ag.

Qualified persons

Terre Lane (MMSA, QP), principal mining engineer for Global Resource Engineering Ltd., is an independent qualified person as defined by National Instrument 43-101 and has reviewed and approved the contents of this news release. Ms. Lane is responsible for the 2023 mineral resource estimate for the Eskay Creek deposit. In accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects, Mr. Geddes, PGeo, senior vice-president, exploration and resource development, is the qualified person for the company and has validated and approved the technical and scientific content of this news release. The company strictly adheres to CIM best practices guidelines in conducting, documenting and reporting the exploration activities on its projects.

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