Horizon Minerals Limited has announced a significant update to its gold mineral resource, increasing contained ounces to 1.88 million by lowering cutoff grades and accounting for mining depletion. This comprehensive update spans multiple key deposits and sets the stage for upcoming development studies.
- Total gold mineral resources now 34.32Mt at 1.7 g/t Au for 1.88Moz
- Resource increase driven by lower cutoff grades and mining depletion
- Key deposits updated include Boorara, Phillips Find, Crake, Coote, Golden Ridge North, Kalpini, Jacques-Peyes, Gordons Dam
- Detailed geological and sampling methodologies underpin resource estimates
- Supports sustained production and upcoming Black Swan feasibility study
Overview of the Resource Update
Horizon Minerals Limited (ASX – HRZ) has released an updated gold mineral resource statement that reflects a robust 16% increase in tonnage and a 6.5% uplift in contained gold ounces, now totaling 1.88 million ounces. This update is underpinned by a strategic lowering of cutoff grades from 0.8 g/t to 0.5 g/t gold, reflecting the sustained rise in gold prices that have rendered previously marginal lower-grade tonnages economically viable.
The company’s cornerstone assets, notably Boorara and Phillips Find, have been adjusted for mining depletion through mid-2025, while other deposits such as Crake, Coote, Golden Ridge North, Kalpini, Jacques-Peyes, and Gordons Dam have been re-evaluated with the new cutoff parameters. This comprehensive resource base, totaling 34.32 million tonnes at an average grade of 1.7 g/t Au, forms a solid foundation for Horizon’s development plans and continuous cash flow generation.
Technical and Geological Insights
The resource update is supported by extensive drilling and sampling programs, employing a combination of Reverse Circulation (RC), Diamond Drilling (DD), and Grade Control RC methods. Horizon has applied rigorous quality assurance and control protocols, including duplicate sampling and certified reference materials, ensuring the reliability of assay data.
Geological interpretations have been refined across deposits, with detailed 3D modelling of mineralisation domains and structural controls. For example, at Boorara, mineralisation is hosted within the Boorara Shear Zone, with distinct lode systems such as Regal, Crown Jewel, and Royal, each exhibiting unique vein orientations and mineralisation styles. Similar detailed geological frameworks underpin other deposits, facilitating accurate resource estimation using advanced geostatistical techniques like Ordinary Kriging and dynamic anisotropy.
Implications for Development and Production
Managing Director and CEO Grant Haywood highlighted that the resource upgrade positions Horizon with a more robust platform for future development. The increased inventory is set to be incorporated into the Black Swan feasibility study, expected in the March 2026 quarter, which will further define the company’s production profile.
Mining depletion at Boorara and Phillips Find has been carefully accounted for, with detailed reconciliations planned post-mining completion in late 2025. The resource update also reflects ongoing technical studies and metallurgical test work, which indicate favourable processing characteristics across deposits, supporting the economic extraction assumptions.
Environmental and Regulatory Considerations
Horizon’s projects are located in established mining districts near Kalgoorlie-Boulder, Western Australia, with tenements in good standing and no known impediments to operations. Environmental assumptions are based on local experience with similar deposits, indicating low acid-forming potential and manageable waste disposal options. The company continues to monitor and assess environmental impacts as part of its development planning.
Looking Ahead
This resource update not only enhances Horizon’s gold inventory but also signals a strategic response to evolving market conditions, particularly the sustained gold price uplift. The detailed technical work and resource reclassification at lower cutoff grades demonstrate the company’s commitment to maximising asset value and operational flexibility.
Bottom Line?
With a strengthened resource base and upcoming feasibility studies, Horizon Minerals is poised to advance its gold production ambitions amid favourable market conditions.
Questions in the middle?
- How will the upcoming Black Swan feasibility study incorporate the updated resource figures?
- What are the potential impacts of further drilling on the classification of Inferred resources?
- How might fluctuations in gold prices affect the economic viability of lower-grade mineralisation?