Polymetals Hits 45m of High-Grade Silver-Zinc in Zone Written Off Since 1996
Underground drilling confirms high-grade silver-lead-zinc mineralisation at Endeavor Mine
Polymetals Resources has confirmed broad zones of high-grade mineralisation remain intact in the Upper Main Lode at Endeavor Mine, adjacent to existing mine infrastructure. Results are from the first 12 holes (713.6 m) of a 34-hole, 3,100 m underground diamond drilling campaign. The company’s reinterpretation suggests the 1996 ground collapse affected a materially smaller area than previously assumed, creating potential to add high-grade tonnes to Endeavor’s mining inventory.
The drilling programme targets the Upper Main Lode at Endeavor Mine in the Cobar Basin, New South Wales. Polymetals’ reassessment of historical mine records and new drilling data indicate that substantial volumes of high-grade silver-lead-zinc mineralisation persist adjacent to the interpreted collapse boundaries and remain accessible from existing underground development.
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Standout assay results from the drilling programme
Eleven of the first 12 holes intersected significant mineralisation. Assay results demonstrate grade and width comparable to the existing Endeavor resource base, with silver equivalent (AgEq) figures conveying total metal value across the polymetallic system.
| Hole ID | Interval (m) | Silver Equivalent (g/t AgEq) | Silver (g/t) | Zinc + Lead (%) |
|---|---|---|---|---|
| POL009 | 45.2 | 436 | 197 | 19.9% |
| POL002 | 33.0 | 439 | 209 | 18.0% |
| POL010 | 33.0 | 408 | 205 | 15.1% |
| POL007 | 24.5 | 473 | 207 | 19.0% |
| POL011 | 26.7 | 439 | 227 | 16.4% |
| POL008 | 14.9 | 494 | 304 | 14.4% |
These intercepts represent substantial widths at grades comparable to the existing Endeavor resource (average 8.0% Zn, 4.5% Pb, 84 g/t Ag), suggesting potential for economic extraction. The polymetallic nature of the deposit delivers value across silver, lead, and zinc, with copper and gold credits.
What is a stope collapse and why does this matter?
A stope is an underground cavity created during ore extraction. In 1996, a stope collapse at Endeavor’s Upper Main Lode led operators to assume the surrounding mineralisation was inaccessible or destroyed. Polymetals’ geological review of historical records and underground inspections suggests the collapse zone is smaller than the previous interpretation.
Mineralisation adjacent to the collapse boundaries appears to remain intact and accessible from existing underground development. If the company can demonstrate the collapse-affected area is materially smaller, significant high-grade tonnes could be rehabilitated into the mining inventory without major new infrastructure expenditure. This represents a lower-risk, lower-capital pathway to mining inventory growth compared to greenfields extensions.
Executive Director commentary
Jess Oram, Executive Director
“What makes these results particularly important is their location. The mineralisation occurs within an established mining environment, close to existing infrastructure and immediately adjacent to the high-grade Upper North Lode.”
Oram emphasised that the reassessment of the 1996 stope collapse has opened the opportunity to define substantial volumes of in-situ mineralisation which remain intact. The proximity to the Upper North Lode, a high-grade zone already in the mine plan, enhances the strategic value of the Upper Main Lode drilling.
Strategic location within the Endeavor Mine complex
The Upper Main Lode sits within an established mining environment, adjacent to existing development and the high-grade Upper North Lode. Drilling was conducted from underground drill sites using NQ diamond core methods, with contractor DRC Drilling Pty Ltd completing the programme under Polymetals’ supervision.
The company employed NQ3 triple-tube diamond core drilling to maximise sample recovery. Core was oriented using a Reflex back-end integrated core orientation tool, though limited success was achieved in running out the orientation line due to core presentation. Proximity to existing infrastructure could streamline any future mining activities, reducing both capital intensity and project execution risk.
Mining inventory additions in well-developed areas typically carry lower capital intensity than greenfields extensions. The Upper Main Lode’s location within the established Endeavor Mine complex positions it as a near-mine opportunity with potential to deliver early cash flow.
Next steps for the drilling campaign
Assay results to date have provided sufficient encouragement to continue the full 34-hole programme. The programme is designed to improve geological confidence, assess mineralisation continuity, and support evaluation of potential mining opportunities within the Upper Main Lode area.
- Total programme: 34 holes for approximately 3,100 m
- Completed to date: 12 holes for 713.6 m
- Remaining: 22 holes for approximately 2,400 m
- Gold assays pending for some intervals
Continued drilling success could support a meaningful resource update and potential mine plan revision. The remaining holes will focus on defining the scale and continuity of mineralisation adjacent to the collapse zone boundary, with results expected progressively as assays are received.
Endeavor Mine resource base and production context
Endeavor Mine is located in the Cobar Basin, one of Australia’s premier polymetallic provinces. The deposit is characterised by polymetallic massive sulphide mineralisation dominated by silver, lead, and zinc, with copper and gold credits. The existing underground Mineral Resource and Ore Reserve provide context for the Upper Main Lode drilling.
| Category | Tonnes (Mt) | Zinc (%) | Lead (%) | Silver (g/t) |
|---|---|---|---|---|
| Underground Mineral Resource | ||||
| Measured | 4.4 | 8.3% | 5.1% | 93 |
| Indicated | 8.8 | 7.9% | 4.6% | 82 |
| Inferred | 3.1 | 7.7% | 3.7% | 78 |
| Total | 16.3 | 8.0% | 4.5% | 84 |
| Stage 1 Ore Reserve (includes 3.4 Mt tailings) | ||||
| Proved (UG) | 0.9 | 6.17% | 3.82% | 92 |
| Probable (UG) | 2.3 | 6.80% | 2.07% | 55 |
| Probable (Tailings) | 3.4 | 2.14% | 1.56% | 80 |
| Total Reserve | 6.6 | 4.32% | 2.04% | 73 |
The Upper Main Lode drilling has potential to add high-grade tonnes to an already sizeable resource inventory, strengthening Endeavor’s mine life. The existing resource base demonstrates the scale of the Endeavor system, with the Upper Main Lode representing a near-mine opportunity to expand that base.
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Investment implications
Polymetals is demonstrating that areas previously written off may contain mineable mineralisation. Success in the remaining 22 holes could support near-term resource growth, though further work is required to fully define the collapse zone boundary and confirm geotechnical conditions.
- High-grade intercepts confirm mineralisation persists adjacent to the 1996 collapse zone
- Proximity to existing infrastructure reduces potential capital requirements
- Full 34-hole programme continues with results expected progressively
- Potential to add meaningful tonnes to Endeavor’s mining inventory
The drilling programme represents a systematic approach to rehabilitating a previously sterilised area into the mining inventory. If successful, this could extend Endeavor’s mine life and improve project economics without the capital intensity associated with greenfields exploration.
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