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

Upper Main Lode Drilling at Endeavor Mine Confirms Historic Subsidence Reinterpretation

Polymetals Resources has been advancing an underground diamond drilling program targeting the upper Main Lode at the Endeavor Mine in Cobar, New South Wales. The latest drilling phase continues to validate the company’s reinterpretation of a 1996 subsidence event, which has important implications for exploration strategy by indicating substantial high-grade mineralisation beyond the historically affected zone.

The drilling has evolved from an exploratory proof-of-concept to a focused effort defining mineralisation suitable for Mineral Resource estimation. Each drillhole completed in this phase has intersected significant silver-lead-zinc mineralisation, substantially increasing geological confidence. Rather than isolated ore remnants, the drilling is delineating the geometry and continuity of the mineralised system, suggesting the upper Main Lode could significantly augment the Endeavor mining inventory.

Outstanding Intercept Lengths and Grades Across Nine Drillholes

Recent assay results reveal impressive intercept widths paired with high silver, zinc, and lead grades. Drillhole POL015 intersected 96.6 metres at 604 AgEq (390 g/t silver, 8.8% zinc, 5.4% lead), marking one of the most notable intercepts. Drillhole POL016 returned 48.4 metres at 666 AgEq (451 g/t silver, 7.8% zinc, 6.1% lead), and POL013 intersected 68.1 metres at 429 AgEq (203 g/t silver, 9.5% zinc, 5.5% lead).

Additional significant results include POL014 with 45.7 metres at 571 AgEq (387 g/t silver, 7.2% zinc, 5.6% lead) and POL020, which yielded two intercepts—40.0 metres at 497 AgEq and 30.0 metres at 718 AgEq (428 g/t silver, 9.7% zinc, 12.9% lead). These consistent results across multiple drillholes and depths within the upper Main Lode highlight the robustness of the mineralisation. The company underscores that both the exceptional widths and grades, alongside the consistency across drillholes, are critical findings.

Geological Confidence Enables Start of Mineral Resource Modelling

Given the consistent mineralisation across nine completed drillholes, Polymetals Resources has deemed geological confidence sufficient to begin formal Mineral Resource modelling for the upper Main Lode. This marks a key advancement from exploration to defining geometry and continuity necessary for resource estimation. The drilling approach now reliably predicts mineralisation, indicating progression beyond validation toward systematic resource definition.

Executive Exploration Director Jess Oram highlighted this transition, stating, "the program is now transitioning from proving the concept to defining the geometry and continuity required for resource estimation." The company aims to release an updated Mineral Resource estimate for the upper Main Lode later in 2026, contingent on completing the remaining drilling and final geological interpretations. This sets the stage for a formal resource statement to guide future mine planning and development at Endeavor.

Remaining Drilling Targets Collapse Zone Boundaries and Resource Parameters

Polymetals Resources continues underground diamond drilling within the upper Main Lode area. Remaining drillholes are designed to achieve multiple goals: delineate the interpreted collapse zone limits from the 1996 event, enhance geological confidence and continuity of mineralisation, and support geological modelling and Mineral Resource estimation.

Moreover, the ongoing drilling seeks to identify additional high-grade tonnes for incorporation into future mine plans at Endeavor. This indicates the company’s dual focus on defining a resource and identifying economically recoverable mineralisation. The methodical drilling strategy and consistent results underscore a systematic approach to mapping the upper Main Lode and establishing its potential contribution to future mining operations.

Consistent Drillhole Results Confirm Continuity of High-Grade Mineralisation

A key highlight of the program is the uniformity of results across the nine new drillholes. Every hole intersected significant mineralisation within the target zone, confirming broad, continuous high-grade mineralisation adjacent to existing underground workings at Endeavor. This contrasts with sporadic mineralisation often encountered in exploration, suggesting the upper Main Lode forms a well-defined mineralised system.

The proximity of these high-grade zones to current underground development is particularly important, implying potential ease of access and lower development costs for future extraction. The drilling confirms continuity of mineralisation near existing infrastructure, which may facilitate integration of upper Main Lode material into mine planning. Although economic parameters and mining studies have not yet been disclosed, this proximity is relevant for future economic assessments and mine design.

Polymetals Resources’ Exploration and Mining at Cobar

Polymetals Resources Limited is an Australian minerals exploration and mining company focused on the Endeavor Mine near Cobar, New South Wales. The Endeavor Mine is a silver-lead-zinc deposit central to the company’s exploration and development activities. Cobar is a well-established mining district with a history of precious and base metal mining, and Endeavor represents a key asset in Polymetals’ portfolio.

The company’s operations focus on underground exploration and development of the Endeavor deposit, employing diamond drilling and geological interpretation to define and expand mineral resources. The emphasis on silver-lead-zinc reflects the commodity mix at Endeavor, with silver grades notably high in recent drilling. Polymetals’ head office is located at 627 Stafford Road, Stafford, Queensland. Further information is available via email at [email protected] or on the company website polymetals.com.

Technical Drilling Methodology and Parameters for Upper Main Lode Program

The drilling program uses underground diamond drilling (DDH) to target the upper Main Lode. Drillholes range from approximately 13.8 metres (POL018) to 128.0 metres (POL015) in depth, with varied dip angles and azimuths to intersect mineralisation from multiple orientations. Collar locations are precisely surveyed using GDA94 Zone 55 coordinates, with elevations recorded relative to mine grid and relative level (RL) measurements, ensuring spatial accuracy of intersections.

Assays report silver (Ag) in grams per tonne, zinc (Zn) and lead (Pb) as percentages, and copper (Cu) also as percentages. Estimated true widths (ETW) are provided separately from downhole intervals to reflect actual mineralised zone thickness. Silver equivalent (AgEq) values combine silver, zinc, lead, and copper into a single metric; gold assays remain pending and will be reported separately. This methodology aligns with industry standards for base and precious metal exploration.

Pending Assay Results and Upcoming Drilling Updates

Several drillholes remain pending assay results, including POL017, POL019, POL021, POL022, POL023, POL024, and POL025. Some gold assays are outstanding and will be released separately. Follow-up or re-drilling activities include POL022A and POL022B.

These forthcoming results will enhance geological interpretation and support Mineral Resource modelling. The phased release of assay data and targeted drill designs indicate a managed approach to refining understanding of the upper Main Lode’s mineralisation geometry and continuity. Additional results will further inform the Mineral Resource estimate planned for late 2026.

Mineral Resource Estimate Schedule and Investor Implications

Polymetals Resources plans to complete an updated Mineral Resource estimate for the upper Main Lode later in 2026, pending drilling completion and final geological interpretation. This milestone is significant for the company and investors tracking the Endeavor asset’s development. A formal Mineral Resource estimate, prepared under JORC Code standards, will provide an independent assessment of tonnage and grade defined at the upper Main Lode.

This resource estimate will underpin future feasibility studies, mine planning, and economic evaluations. Investors should monitor for its release alongside geological reports or technical presentations that clarify the upper Main Lode’s economic potential within Endeavor. The transition from exploration drilling to resource estimation reflects growing confidence, although formal economic viability and mining parameters remain to be disclosed.