Terrain Minerals Reports Maiden 54,000-Ounce Gold Resource at Lightning Prospect in Western Australia's Murchison Region

Lightning Prospect Achieves Maiden 54,000-Ounce Gold Resource with Dual Mining Scenarios

Independent geological consultancy Apex Geoscience, with competent persons Mr. Kevin Hon, P.Geo, and Mr. Steve Nicholls, M.AIG, completed the maiden Mineral Resource Estimate for Terrain Minerals' Lightning Prospect. The estimate complies with the 2012 JORC Code and includes 677,000 tonnes grading 2.5 grams per tonne gold, equivalent to 54,000 ounces of contained gold, plus 7.2 grams per tonne silver totaling 156,500 ounces across the resource.

The resource is divided into two mining scenarios based on mineralisation and economic viability: an open pit component of 157,000 tonnes at 3.5g/t gold (17,500 ounces) with 23,000 ounces of silver at 4.6g/t, and an underground component of 520,000 tonnes at 2.2g/t gold (36,500 ounces) with 133,500 ounces of silver at 8.0g/t. This dual approach highlights higher-grade mineralisation suitable for underground mining beneath the optimised open pit shell, supporting potential staged development.

Economic Assumptions and Pit Optimisation Underpin Resource Estimate

The resource estimate was constrained within an optimised pit shell based on economic assumptions reflecting realistic mining and processing parameters. The open pit optimisation used a gold price of AUD$6,000 per ounce with 93% recovery and a silver price of AUD$20 per ounce, treating silver as a by-product. Operating costs assumed were AUD$35 per tonne for combined open pit mining, AUD$25 per tonne for processing, and AUD$9 per tonne for general and administrative expenses.

Underground mining costs were set at AUD$100 per tonne to account for higher extraction expenses. The estimate was limited to material within a 0.5g/t gold mineralised envelope and reported at a 0.5g/t gold cut-off grade. Bulk density values were derived from diamond drilling data, with median densities of 2.60 g/cm³ for transitional material and 2.95 g/cm³ for fresh rock. Figures are rounded to the nearest 1,000 tonnes and 500 ounces to reflect estimate accuracy.

Inferred Resource Classification Sets Stage for Future Upgrades

The entire 54,000-ounce gold resource is classified as Inferred Mineral Resources, indicating uncertainty in quantity and grade and insufficient data to classify as Indicated or Measured Resources. The company notes these resources are not mineral reserves and lack demonstrated economic viability, with no reserves calculated for Lightning. There is no assurance any resources will convert to reserves.

However, Terrain Minerals anticipates that most Inferred Resources could be upgraded to Indicated status with ongoing exploration. This upgrade pathway is a strategic opportunity, as Indicated classification improves confidence and project development prospects. The company aims to accelerate exploration to upgrade the resource category and expand the inventory through further drilling.

Mineralisation Extends from Surface and Remains Open Along Strike and at Depth

Mineralisation at Lightning begins at surface and extends to significant depth, remaining open both along strike and at depth per current drilling. This suggests the 54,000-ounce resource is a base estimate rather than the deposit's full potential. Significant known mineralisation lies outside the current resource estimate, indicating strong expansion potential.

The resource is under-drilled north of the main orebody, presenting clear growth targets. Executive Director Justin Virgin highlighted that open mineralisation along strike and at depth positions Lightning for further resource expansion. Numerous analogous gold targets across the broader Smokebush Project will be advanced to build a substantial gold resource beyond Lightning.

Upcoming Infill and Expansion Drilling to Enhance Resource Confidence and Size

Terrain Minerals plans a drilling campaign combining infill and extensional drilling to upgrade and grow the resource. Infill drilling will target areas within and near the current resource to improve confidence and potentially elevate classifications to Indicated or Measured. Extensional drilling will test mineralisation outside the optimised pit shell and explore under-drilled northern extensions.

Simultaneously, the company will assess new priority targets across Lightning and the Smokebush Project to identify additional mineralisation. This balanced approach aims to enhance resource confidence and discover new resources over a multi-year program.

Metallurgical Testing Program Initiated with Stage One Results Expected in Q3 2026

Terrain Minerals has commenced metallurgical testing to evaluate processing characteristics of Lightning mineralisation. Stage one results are expected in Q3 2026, with further testing planned thereafter. Metallurgical data will inform recovery rates, processing flowsheets, and cost estimates critical for future economic assessments or feasibility studies.

This testing marks progress toward advanced development stages, moving beyond exploration into early engineering and process characterisation.

Strategic Location in Murchison Gold Region Near Major Mines

The Lightning Gold Prospect is located in the prolific Murchison Gold Region, approximately 350 kilometres north of Perth. It benefits from proximity to established mining operations, including Capricorn Metals' Gold Project surrounding Lightning to the north, east, and south, and Vault Minerals' Rothsay Gold Mine to the west. This regional context confirms the presence of gold mineralisation systems within the Smokebush Project area.

As part of Terrain Minerals' 100%-owned Smokebush Gold and Silver Project, Lightning enjoys access to established infrastructure, market expertise, and mining experience in the region. Nearby major mines underscore the economic viability and potential for gold and silver extraction in the Murchison area, supporting Lightning's development prospects.

Silver Potential Highlighted by Historic Drill Hole Reassessment at Monza Structure

The company identified additional silver exploration potential at the Monza structure within Lightning. Historical drilling shows only 28% of holes were assayed for multi-elements including silver, leaving 72% untested for silver grades and indicating a significant data gap.

Terrain Minerals plans to reassess existing samples for silver content to define additional silver ounces without new drilling. The current resource includes 156,500 ounces of silver, with the underground component showing high silver grades of 8.0g/t, highlighting strong silver mineralisation warranting focused evaluation.

Foundation Established for Growth with Significant Upside Potential

Executive Director Justin Virgin described the maiden Mineral Resource Estimate as a major milestone laying a solid foundation for future growth. He emphasized that known mineralisation beyond the current estimate suggests the 54,000-ounce figure is a starting point rather than the full resource potential.

Terrain Minerals’ strategy involves accelerating exploration to upgrade the Inferred resource to Indicated while expanding the resource base. The open mineralisation from surface, ongoing openness at depth and along strike, and multiple priority targets across Smokebush position Lightning as a dynamic growth platform. The integrated infill, extensional drilling, and new target testing reflect a comprehensive approach to maximize resource definition and discovery over coming years.