Polymetals Resources Reports Extensive High-Grade Silver-Lead-Zinc Mineralisation at Endeavor Mine Upper Main Lode

Polymetals’ Endeavor Mine Focuses on Upper Main Lode Silver-Lead-Zinc Mineralisation

Polymetals Resources Ltd operates the producing Endeavor Mine in Cobar, New South Wales, concentrating on silver, lead, and zinc mineralisation. The company’s mining and exploration efforts target maximising value from mineralised zones within this established operation. The upper Main Lode is a key exploration target within the mine’s footprint and central to Polymetals’ operational strategy.

Transitioning from exploratory drilling to resource definition, Polymetals is systematically delineating high-grade mineralisation for integration into future mine planning and resource estimates. The underground location of the upper Main Lode, adjacent to existing development infrastructure, offers operational benefits for potential future extraction.

Reevaluating the 1996 Subsidence Event Unlocks New Mineralisation Potential

Polymetals’ reinterpretation of a 1996 subsidence event underpins the current drilling program. Previously, this event raised doubts about the continuity and geometry of mineralisation in the upper Main Lode. Rather than assuming the subsidence destroyed or displaced mineralisation, the company’s geological team developed an alternative model suggesting significant high-grade mineralisation remains outside the affected zone.

This reinterpretation has guided exploration efforts and is being validated by consistent drilling results. The fact that all nine new drillholes intersected significant mineralisation confirms the geological model’s accuracy and enhances confidence in the mineralised system’s geometry. This validation supports the company’s progression toward formal resource estimation and bolsters investor confidence.

Outstanding Assay Results Highlight Broad, High-Grade Mineralised Zones

Recent assay results demonstrate exceptional widths and consistent high grades across multiple drillholes. Hole POL015 intersected 96.6 metres at 604 g/t silver equivalent (390 g/t silver, 8.8% zinc, 5.4% lead), while hole POL016 delivered 48.4 metres at 666 g/t AgEq (451 g/t silver, 7.8% zinc, 6.1% lead). Additional highlights include 68.1 metres at 429 g/t AgEq from POL013, 45.7 metres at 571 g/t AgEq from POL014, and a 30-metre interval at 718 g/t AgEq from POL020 featuring 12.9% lead.

The broad mineralised intervals, ranging from approximately 30 to nearly 100 metres true width, indicate substantial, continuous zones rather than isolated lenses. The consistent silver, zinc, and lead grades across drillholes demonstrate a coherent mineralised system with predictable characteristics, essential for robust resource estimation. The exceptional lead grade in POL020 highlights zones of elevated precious and base metal content within the system.

Advancing from Proof-of-Concept to Mineral Resource Definition and Modelling

Polymetals has confirmed the drilling program’s transition from proof-of-concept to resource definition. Initial drilling validated the geological model and confirmed substantial mineralisation. With consistent intersections across nine drillholes, the focus now shifts to defining the mineralised system’s limits, geometry, and tonnage for formal Mineral Resource estimation.

Geological confidence has reached a level allowing Mineral Resource modelling to commence. An updated Mineral Resource estimate for the upper Main Lode is targeted for release later in 2026, contingent on ongoing drilling completion and final geological interpretation. This milestone marks significant progress in the project’s development and reflects management’s confidence in the data quality and geological understanding.

Ongoing Drilling Program Targets Collapse Zone Limits and Resource Confidence

Underground diamond drilling continues at the upper Main Lode, with holes POL017, POL019, POL021, POL022, POL023, POL024, and POL025 pending assay results. The remaining drilling aims to delineate the interpreted collapse zone boundaries, reduce geological uncertainties, and enhance confidence in mineralisation continuity.

The program also supports geological modelling and resource estimation by collecting data from strategically selected locations. Polymetals is evaluating opportunities to incorporate additional high-grade tonnes into mine planning, indicating a forward-looking approach that integrates exploration with practical mining scenarios. The varied drillhole orientations reflect a systematic three-dimensional sampling strategy designed to produce a robust, well-constrained resource model.

Consistent Mineralisation Across Drillholes Supports Resource Estimation Confidence

The drilling results reveal strong geological continuity and consistency. Except for one hole (POL004) with no significant intersection, all completed holes have intersected mineralisation. Silver grades range from approximately 100 to 451 g/t, zinc from 7% to 15%, and lead from 5% to 13%, indicating a coherent mineralised system.

This consistency is crucial for resource estimation, confirming that mineralisation is not erratic or confined to narrow zones. It supports the assumption of grade continuity required for resource block modelling. Exploration Director Jess Oram emphasized the importance of both exceptional widths and grades and the consistency across drillholes, which reduces uncertainty and supports higher confidence resource classifications planned for 2026.

Upper Main Lode Could Significantly Enhance Endeavor Mine’s Inventory and Planning

Polymetals describes the upper Main Lode as having "the potential to become a meaningful addition to the Endeavor mining inventory," highlighting its strategic importance. Proximity to existing underground infrastructure offers operational and economic advantages by reducing mining development costs.

The company’s focus on integrating additional high-grade tonnes into future mine planning suggests potential acceleration of development and mining activities in this area. Incorporating new high-grade ore could extend mine life, increase production, and boost near-term cash flow, factors important to investors assessing the company’s outlook.

Pending Assays and Timeline for Updated Mineral Resource Estimate

Gold assay results remain outstanding and will be reported separately. Several drillholes, including POL017, POL019, POL021, POL022, POL023, POL024, and POL025, await assay results. While the total number of planned holes and drilling completion date have not been disclosed, the targeted Mineral Resource estimate release later in 2026 implies drilling will conclude within the coming months.

The Mineral Resource estimate timing depends on drilling completion and final geological interpretation, ensuring resource modelling is based on comprehensive and validated data. Investors will monitor updates on drilling progress, assay results, and any changes to the Mineral Resource estimate schedule. The forthcoming resource update will provide a code-compliant quantification of the mineralisation discovered.

High-Quality Drill Core and Methodical Approach Validate Geological Targeting

Polymetals notes that drilling has "progressed beyond proof-of-concept," with the methodology consistently predicting mineralisation. Underground diamond drilling in a producing mine requires precise hole placement and angle control, and the consistent results indicate effective execution.

Detailed collar survey data and varied hole orientations demonstrate a professional, systematic drilling program designed to sample the mineralised zone in three dimensions. This methodical approach, combined with consistent intersections, confirms the geological interpretation’s robustness and provides a solid foundation for forthcoming resource modelling based on high-quality data.