Polymetals Confirms High-Grade Silver Zones in Area Written Off Since 1996 Collapse

By William Hadrian -

Polymetals confirms high-grade silver-lead-zinc mineralisation at Endeavor Mine

Polymetals Resources has confirmed broad zones of high-grade silver-lead-zinc mineralisation in the Upper Main Lode at the Endeavor Mine in New South Wales’ Cobar Basin. Underground diamond drilling has returned significant intersections from 11 of the first 12 holes completed in a 34-hole campaign, with results demonstrating that substantial volumes of mineralisation remain intact in an area previously considered largely sterilised following a 1996 ground collapse.

The program has completed 12 holes for 713.6 m of a planned 34-hole, ~3,100 m drilling campaign. Reinterpretation of historical mine records, survey data and underground inspection suggests the collapse zone may be materially smaller than previously assumed, creating the opportunity to define high-grade tonnes adjacent to existing mine development and infrastructure.

The mineralisation occurs within an established mining environment, close to existing infrastructure and immediately adjacent to the high-grade Upper North Lode, enhancing the potential to convert this area into mining inventory with minimal additional development.

Drilling returns substantial silver, lead and zinc intercepts

The first 12 holes have returned thick, consistent intercepts of high-grade polymetallic mineralisation. The standout results demonstrate the scale and quality of mineralisation that persists in the Upper Main Lode target area.

Upper Main Lode Drilling Progress and Highlights

Hole ID Interval (m) Est. True Width (m) AgEq (g/t) Ag (g/t) Zn (%) Pb (%)
POL009 45.2 43 436 197 8.9 11.0
POL002 33.0 26 439 209 9.9 8.1
POL010 33.0 32 408 205 9.6 5.5
POL007 24.5 22 473 207 12.2 6.8
POL011 26.7 23 439 227 9.3 7.1
POL008 14.9 12 494 304 8.5 5.9

The grades and widths are substantial for a polymetallic deposit, particularly given the intercepts occur in an area with established mining infrastructure. The true widths range from 12 m to 43 m, with silver equivalent grades between 408 g/t and 494 g/t AgEq.

What is silver equivalent and why does it matter?

Silver equivalent (AgEq) is a standardised way to express the combined value of multiple metals in a single figure. Polymetals uses silver as the base metal because it is the dominant metal at Endeavor, allowing investors to compare intercepts and understand total contained value without calculating individual metal contributions.

The calculation incorporates metal price assumptions of US$62/oz silver, US$3,500/t zinc, US$13,600/t copper and US$1,950/t lead, along with expected metallurgical recoveries of 80% silver, 89% zinc, 85% copper and 85% lead. These inputs reflect current market conditions and processing performance at the operation.

Understanding AgEq helps investors assess the economic potential of polymetallic intercepts in a single metric, simplifying comparison across drill holes and deposit areas.

Reinterpretation of 1996 collapse zone creates new opportunity

A ground collapse during mining operations in 1996 led to this area being considered largely sterilised for nearly three decades. Recent review of historical mine records, survey data and underground inspection indicates the collapse zone may be materially smaller than previously interpreted.

This reinterpretation has created the opportunity to define substantial volumes of in-situ mineralisation that remain intact. The drilling program is designed to define the boundaries of the collapse zone and assess the continuity and scale of mineralisation adjacent to those boundaries, with potential to add high-grade tonnes to Endeavor’s mining inventory.

If the collapse zone is confirmed to be smaller than historically assumed, significant high-grade mineralisation may be recoverable from an area that was previously excluded from mine planning, potentially extending mine life and improving the production profile.

Executive Director outlines strategic importance

Executive Director Jess Oram emphasised the significance of the drilling results and the strategic value of the target area’s location within the existing mining environment.

Jess Oram, Executive Director

“The results from the first 12 holes provide strong support for that view. Every hole (bar one) has intersected significant mineralisation demonstrating that substantial volumes of high-grade silver-lead-zinc remain intact adjacent to the collapse boundaries.”

“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.”

The proximity to existing infrastructure and the high-grade Upper North Lode enhances the potential to convert this area into mining inventory.

Drilling program continues with 22 holes remaining

The remaining scope comprises 22 holes still to be completed from the 34-hole program (approximately 3,100 m total). The program is designed to improve geological confidence, assess continuity of mineralisation and support evaluation of potential future mining opportunities within the Upper Main Lode area.

Assay results to date have provided sufficient encouragement to continue the program, with the objective of defining the scale and continuity of mineralisation and supporting potential future mining additions to Endeavor’s inventory.

Program objectives

The ongoing drilling program has three key objectives:

  1. Define the scale and continuity of mineralisation within and around the reinterpreted collapse zone
  2. Improve geological confidence in the Upper Main Lode area
  3. Support evaluation of potential future mining additions to Endeavor’s inventory

Continued drilling success could support a meaningful addition to Endeavor’s future mining inventory, potentially extending mine life and improving the production profile with high-grade tonnes in close proximity to existing development.

Endeavor’s existing resource base

Endeavor’s current underground Mineral Resources total 16.3 Mt at 8.0% Zn, 4.5% Pb and 84 g/t Ag. The Stage 1 Ore Reserve totals 6.6 Mt at 4.32% Zn, 2.04% Pb and 73 g/t Ag, providing a substantial base for near-term production.

Category Tonnes (Mt) Zn (%) Pb (%) Ag (g/t)
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

The Upper Main Lode drilling has the potential to add incremental tonnes to an already substantial resource base at attractive grades, particularly given the high-grade nature of the intercepts returned to date.

What this means for Polymetals investors

The drilling has confirmed mineralisation persists in an area previously considered unmineable, with 11 of 12 holes intersecting significant polymetallic mineralisation. The proximity to existing infrastructure reduces potential development costs if mineralisation is converted to reserves, as the target area is adjacent to established mine development and the high-grade Upper North Lode.

Continued success in the remaining 22 holes could support a meaningful uplift to Endeavor’s mining inventory. Polymetals is focused on cost-efficient development and production of high-grade silver and zinc assets, and the Upper Main Lode represents a potential low-cost addition to Endeavor’s production profile given existing access and infrastructure.

The reinterpretation of the 1996 collapse zone has created an opportunity to define substantial volumes of high-grade mineralisation that may be recoverable from an area excluded from mine planning for nearly three decades, potentially extending mine life and improving the economic profile of the operation.

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Frequently Asked Questions

What are the Polymetals Endeavor Mine high-grade results from the latest drilling?

Polymetals has returned intercepts of up to 494 g/t silver equivalent across true widths of up to 43 metres from the Upper Main Lode at Endeavor Mine, with 11 of the first 12 holes hitting significant silver-lead-zinc mineralisation in an area previously considered unmineable.

What is silver equivalent (AgEq) and how does Polymetals calculate it?

Silver equivalent is a single figure that combines the value of multiple metals — silver, zinc, lead and copper — into one comparable metric. Polymetals calculates it using metal price assumptions of US$62/oz silver, US$3,500/t zinc, US$1,950/t lead and US$13,600/t copper, adjusted for expected metallurgical recoveries at the Endeavor operation.

Why was the Upper Main Lode at Endeavor Mine previously excluded from mine planning?

A ground collapse in 1996 led to the Upper Main Lode being considered largely sterilised for nearly three decades. Recent reinterpretation of historical mine records and underground inspection now suggests the collapse zone may be materially smaller than assumed, prompting the current 34-hole drilling program to test what remains intact.

How much of the Endeavor Mine drilling program has been completed?

Polymetals has completed 12 of a planned 34 holes, totalling 713.6 metres of an approximately 3,100-metre program, with 22 holes still to be drilled in the Upper Main Lode campaign.

What is Endeavor Mine's existing mineral resource base?

Endeavor's underground Mineral Resources total 16.3 million tonnes at 8.0% zinc, 4.5% lead and 84 g/t silver, with a Stage 1 Ore Reserve of 6.6 million tonnes at 4.32% zinc, 2.04% lead and 73 g/t silver underpinning near-term production.

William Hadrian
By William Hadrian
Partnerships Director
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