Polymetals Resources Confirms High-Grade Drilling at Endeavor Mine Upper Main Lode

Drilling Confirms Consistency at Endeavor Mine as Polymetals Advances Upper Main Lode Resource Work

Polymetals Resources Ltd (ASX: POL) has reported another set of broad, high-grade silver-lead-zinc drill intersections from the upper Main Lode at the Endeavor Mine in Cobar, New South Wales, with the latest underground diamond drilling results continuing to support work toward an initial Mineral Resource estimate later in 2026. According to the ASX release, the newest sulphide assays include up to 39.0 metres at 676 AgEq g/t in hole POL025 and 42.8 metres at 550 AgEq g/t in POL022A.

In the update, the company said the drilling is not only defining the geometry and continuity of the underlying sulphide mineralisation, but also improving understanding of the weathered, oxidised and supergene zone above it. For investors, that matters because a more reliable three-dimensional geological model is a necessary step before an initial Mineral Resource estimate can be completed.

What the Latest Endeavor Drilling Results Show

The latest results continue a pattern established in Polymetals' earlier June and July 2026 updates. According to the announcement, the upper Main Lode drilling is returning substantial widths of high-grade mineralisation rather than isolated narrow intervals.

The most prominent sulphide intersections reported in this release are set out below.

These results are accompanied by another sulphide intersection in POL021 of 20.70 metres at 221 g/t Ag, 5.7% Zn, 4.8% Pb and 0.38 g/t Au, which was also included in the ASX release. The combination of width and grade is central to the company's current geological interpretation.

For investors assessing drilling updates, width is often as important as grade. Broad mineralised intervals can support more flexible mining scenarios than narrow vein-style intercepts, although any economic implications would still depend on future mine planning, engineering and resource classification.

Executive Director Jess Oram said: "The latest drilling continues the remarkable consistency we have seen across the upper Main Lode, while giving us a much clearer understanding of the mineralised system. We are now defining the geometry and continuity of the high-grade sulphide mineralisation, together with the metal zonation through the oxidised and supergene zone above it. This growing geological understanding is reducing uncertainty and strengthening the model that will underpin the initial Mineral Resource estimate for the upper Main Lode later this year."

Why the Oxidised and Supergene Zone Matters

The August 2026 update was not limited to the main sulphide body. Drillholes POL027 to POL030 were designed to test the upper projection of the Main Lode, where mineralisation has been altered by weathering.

In the report, these holes returned generally lower grades than the underlying sulphide zone. However, the geological information appears to be important for modelling the upper part of the system.

According to Polymetals, this upper zone shows pronounced changes in metal distribution, particularly stronger lead enrichment, zinc depletion and generally lower silver grades. In simple terms, the weathering process appears to have changed where metals are concentrated within the upper part of the lode.

That distinction can be important when geologists build a resource model. Different mineral zones may behave differently in terms of continuity, processing response and mining selectivity. Furthermore, the current drilling is helping the company separate mineralisation near the 1996 subsidence zone from remnant material associated with historical Pasminco mining.

How the Programme Has Progressed in 2026

The current drilling campaign has moved through several clear stages in a relatively short period. Each announcement has added more confidence to the geological interpretation rather than changing the overall thesis.

According to the previous and current ASX releases:

1. On 24 June 2026, initial drilling suggested the area affected by the 1996 subsidence event was materially smaller than previously interpreted.
2. On 22 July 2026, further drilling indicated the intersected mineralisation was continuous across multiple holes, allowing Mineral Resource modelling to begin.
3. On 12 August 2026, the company said drilling is now resolving both the sulphide geometry and the upward continuation into the oxidised and supergene zone.

That progression matters because underground remnant mineralisation can be difficult to define with confidence. Historical mining, local collapse zones and incomplete records can all complicate interpretation. In this case, Polymetals is using current drilling together with historical mining, survey and geological information to refine the upper Main Lode model.

Understanding Silver Equivalent and Why Investors Track AgEq

Because Endeavor is a polymetallic deposit containing silver, zinc, lead, copper and gold, single-metal grades only tell part of the story. That is why the company reports many intersections using silver equivalent, or AgEq.

What Is AgEq?

AgEq is a way of combining the value contribution of several payable metals into one comparable grade figure, using silver as the reference metal. This makes it easier to compare one drill intersection with another in a deposit where several metals contribute to potential revenue.

For instance, an interval with strong zinc and lead values may have greater total metal value than its silver grade alone suggests. AgEq is designed to reflect that combined contribution.

How Polymetals Calculates AgEq

According to the ASX announcement, the company uses the following assumptions:

• Metal prices: US$56.5/oz silver, US$3,537/t zinc, US$13,622/t copper, and US$1,887/t lead
• Metallurgical recoveries: 80% silver, 89% zinc, 85% copper, and 85% lead
• Gold is not included in the AgEq calculation

That final point is important. Several of the reported intersections also carry gold values, yet those gold grades are excluded from the silver equivalent number. As a result, the published AgEq figures are based on silver, zinc, lead and copper only.

Why AgEq Helps Investors

AgEq allows investors to compare polymetallic drill results on a more consistent basis. A headline interval such as 39.0 metres at 676 AgEq g/t in POL025 provides a clearer summary of combined metal content than separate metal grades viewed in isolation.

That said, AgEq is still a screening tool rather than a substitute for detailed project economics. Recoveries, concentrate quality, mining method, dilution and metal prices all influence real project value. Nevertheless, for exploration and resource-definition reporting, AgEq remains a useful benchmark.

What Comes Next in the Upper Main Lode Resource Definition Programme

In the August update, Polymetals outlined a series of immediate priorities for the Endeavor upper Main Lode programme. The company said the next phase of work is focused on integrating recent drill results with historical mine data.

The stated objectives are to:

• Define the geometry and limits of remnant mineralisation around the subsidence zone
• Delineate remaining mineralisation near areas of previous Pasminco mining
• Refine metal zonation in the oxidised and supergene zone
• Improve confidence in the continuity and geometry of the sulphide mineralisation
• Support completion of an initial Mineral Resource estimate for the upper Main Lode later in 2026

The progression can be summarised as follows:

Several holes remain pending. According to the release, POL024, POL029 and POL031 to POL036 were still awaiting results at the time of reporting, while Table 2 also includes later planned or completed holes through POL039. That gives the market further potential news flow as assays continue to be processed.

How the New Drilling Compares With the Existing Endeavor Resource Base

The investment relevance becomes clearer when the current upper Main Lode results are viewed against Endeavor's existing JORC 2012 Mineral Resource and Stage 1 Ore Reserve.

Existing Underground Mineral Resource

Stage 1 Ore Reserve

The contrast in silver grade is one of the more visible features. The current underground Mineral Resource averages 84 g/t silver, while the latest upper Main Lode sulphide intercepts reported in this programme range from 358 g/t to 502 g/t silver in the best holes, before considering zinc, lead and gold credits.

This does not mean the final upper Main Lode Mineral Resource estimate will replicate those headline grades across a large tonnage. Resource estimation always includes continuity, density, cut-off assumptions and classification. Even so, the current drilling indicates a grade profile materially above the existing average resource grade in this part of the mine.

Why Investors Are Watching the Endeavor Upper Main Lode

The current ASX update gives Polymetals a defined near-term catalyst path centred on the planned initial Mineral Resource estimate for the upper Main Lode later in 2026. The appeal for investors lies in a combination of grade, width, continuity and location.

Based on the company's announcements, the key investor considerations include:

• Repeated broad intercepts across multiple holes, rather than isolated single-hole results
• High reported AgEq grades, including several intersections above 550 AgEq g/t
• Mineralisation adjacent to existing underground development, which the company has highlighted in prior updates
• Additional pending assays that may add further data to the geological model
• A clear technical milestone, being the first upper Main Lode Mineral Resource estimate

The latest report also suggests that the drilling programme has moved from asking whether high-grade remnant mineralisation exists to defining how much may remain and how it is distributed. That is a different stage of project evaluation and, in addition, typically a more useful one for assessing future inventory potential.

For now, the market focus is likely to remain on two questions. First, whether pending assays continue the pattern of width and grade already reported. Second, whether the initial Mineral Resource estimate later in 2026 captures enough tonnage and continuity to represent a meaningful addition to Endeavor's existing mining inventory.

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