Big Springs Gold Project

The Big Springs Gold Project seamlessly complements Sentinel’s flagship Columbia Project in Montana, reducing single-asset risk while expanding overall portfolio optionality.

Encompassing approximately 93 km² of Carlin-style tenure on the Independence Trend, adjacent to the Jerritt Canyon mining complex and approximately 70 km from the Carlin Trend.

Driven by an experienced North American executive and technical team positioned to capture key operational efficiencies, Sentinel is breathing new life into the asset—building on historical high-grade intercepts such as 18.3 m @ 33.4 g/t Au from 129.5 m in SCC-1483 at North Sammy.³

VIEW MINERAL RESOURCE

³Historical result reported at a 1.0 g/t Au lower cut-off, length-weighted with no top cut. Refer to ASX announcement dated 2 July 2026.

KEY Highlights

1.01 MOZ MINERAL RESOURCE

55% Measured & Indicated (JORC 2012)

EXPLORATION UPSIDE

Shoots open at depth; only 29 holes deeper than 305 m

NEVADA, NEAR PROCESSING INFRASTRUCTURE

Jerritt Canyon roaster ~42 km by road

PAST-PRODUCING

386 koz produced 1987–93; approved 2017 Mine Plan of Operations (over part of the project area)

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Total Mineral Resource (all categories)*

1.01Moz Global Resource: 15.5Mt @ 2.0g/t Au containing 1,014,000 ounces of gold.
High Confidence Ounces: 555,000oz (55%) classified in Measured & Indicated categories.
Resource Breakdown: Measured: 129koz @ 4.7g/t Au; Indicated: 426koz @ 2.2g/t Au; Inferred: 459koz @ 1.7g/t Au.
Historical Production: 386koz Au extracted across seven open pits between 1987 and 1993.

Permitting & Fast-Track Advantage

2017 Mine Plan of Operations (USFS) in place over part of the project area. Sentinel is working with its permitting advisers to confirm the pathway for drilling, bulk sampling and a potential restart. Any restart is subject to studies, permitting and funding.
Sentinel is working with its permitting advisers to confirm the pathway for drilling, bulk sampling and a potential restart under the 2017 MPO. Any restart is subject to studies, permitting and funding.

Nearby Processing Infrastructure

Proximity to Roasters: third-party processing is a potential option; the nearest roaster is Jerritt Canyon, approximately 42 km by road
Nearest roaster: Jerritt Canyon (third-party owned), approximately 42 km by road. Sentinel is assessing third-party processing options in the region.

Exploration & High-Grade Upside

Minimal Deep Drilling: Highly under-explored at depth, with only 29 historical drill holes exceeding 305 m (1,000 ft) across the entire 93 km² land package.
Open High-Grade Shoots: At least seven northwest-oriented mineralised shoots remain open down-dip and along strike at North Sammy.
District-Scale Targets: Untested Jerritt Canyon-style carbonate-hosted targets located within 300m depth, alongside untested structural extensions beneath McAfee Quartzite (upper-plate) cover.

Development pathway

Historical mine planning identified the 601 pit and the 601 and 701 underground areas as potential initial mining areas. Any restart is subject to studies, permitting and funding.
Established Mine Design: Small Mine Development (SMD) completed an operational plan covering surface and underground mining areas.

*Figures may not sum due to rounding.