- Winston Tailings Assays Confirm Gold, Gallium, Silver, Zinc, Copper & Cobalt
- Tailings Sample Assay Results Exceed Expectations
July 31, 2025 (Source) — Panther Metals Plc (LSE: PALM), the exploration company focused on mineral projects in Canada, is very pleased to announce the receipt of assay results for the recent mine tailings sampling programme undertaken at the Winston Project, located on the historic Winston Lake Mine tailings storage facility (“TSF”) in Ontario, Canada.
The tailings assay results exceed Panther’s expectations returning high grade gold (Au), gallium (Ga), silver (Ag), zinc (Zn), copper (Cu) and cobalt (Co), strongly supporting further sampling and metallurgical testwork to determine the most economic and environmentally sensitive route for extracting the precious metals and other critical minerals from the TSF.
In addition, a rock sample from a historical massive sulphide dump at the Pick Lake deposit located circa 1.4km west of the TSF yielded 25.3% Zn, 3.0% Cu, 0.55g/t Au. 119 g/t Ag, 388 ppm Co and 26.2 ppm Ga which points to the future potential offered by the strong exploration targets in the Pick Lake area.
Highlights
- Tailings samples return assay results of up to:
- 0.814 g/t Au
- 21.9 g/t Ag
- 2.20% Zn
- 0.20 % Cu
- 496 ppm Co
- 122 ppm Ga
- Winston Lake Mine was operational from 1988 to 1998, producing approximately 3.3 million tonnes of ore and yielding zinc, copper, silver, and gold.
- Based on historic processing recoveries it is believed that a significant quantity of valuable material was not captured and remains in the tailing storage facility. These assay results confirm that is the case.
- Massive-sulphide rock sample taken from dump at the Pick Lake deposit yielded 25.3% Zn, 3.0% Cu, 0.55g/t Au. 119 g/t Ag, 388 ppm Co and 26.2 ppm Ga.
- Existing infrastructure including grid power, water treatment and storage facilities support fast-track of tailings reprocessing opportunity.
Darren Hazelwood, Chief Executive Officer, commented:
“These exciting assay results confirm our best hopes for the considerable value potential of precious metals and critical minerals stored within the Winston tailings pond.
The historical production records, summarised in the 2021 Feasibility Study and documented in mining production reports, pointed to a significant proportion of gold passing through the processing plant and into the tailings. As the processing plant was only optimised to produce high-grade zinc and copper concentrates and gold prices were considerably lower than today.
The tailings assay results confirm this belief and strongly point to the tailings containing considerable in-situ value at today’s commodity prices. Whilst we will now have to do the detailed metallurgical studies and recovery plant design, we see the potential for near-term cashflow and profits in the many millions.
As an actively maintained brownfield site much of the needed infrastructure is already in place for the tailings reprocessing, including high-voltage grid power, active water treatment facilities, and the pond in a topographic location that could allow for the tailings to be removed, treated and placed back. This is a dream scenario for a junior exploration company.
We are now aggressively pursuing this opportunity to generate significant returns and have already engaged with internationally renowned mineral processing experts and had conversations with our drilling contractor to plan a comprehensive metallurgical sampling programme.
We believe revenue from the tailings has the potential to both fund the Winston resource growth drilling and mine redevelopment, to fund exploration across our portfolio and to supplement our Bitcoin Treasury. The cashflow will provide Panther the opportunity to develop any discoveries on our own terms not beholden to the market, and will underpin our ability to attract non-dilutive finance.
It is very early in this exciting journey and we now have to do the necessary technical studies to prove up our vision. That said, should the economics of the tailings project be as robust as we currently envisage, we would ideally seek debt finance, rather than use the equity markets, in order to protect our shareholder’s value and avoid dilution as much as possible. Thus, rewarding current and new investors to participate in Panther’s future.”
Background
As announced 15 July 2025, Panther recently undertook a preliminary sampling programme as a first step in assessing the potential to reprocess historical mine tailings, aiming to unlock residual metal value, extend project life, improve overall returns, and contribute to the long-term environmental rehabilitation of the site.1
The Winston Lake Mine was operational from 1988 to 1998, producing approximately 3.3 million tonnes of ore and yielding zinc, copper, silver, and gold. Based on historic recoveries from mining activities in the 1980s and 1990s, it is believed that a significant quantity of valuable material remains in the tailing storage facility (Figure 1).
A total of 14 samples were collected at an overage spacing of 50m down the longitudinal axis of the tailings storage facility (“TSF”), see Figure 2. Each sample comprised an average of 0.8kg of material taken from the top circa 30cm of the submerged tailings below a water cover depth of between 1 to 5 metres. The samples were collected using a boat and extendable sampling auger.
The samples were submitted to accredited AGAT Laboratories in Thunder Bay for gold fire assay with ICP-OES finish and by multi-element four-acid digestion followed by an ICP-OES / ICP-MS finish (AGAT methods 202-552 and 201-071 respectively). Samples which returned silver, copper, zinc and/or sulphur above the upper detection limit were analysed by Overlimit analytical method 201-470. The assay results are summarised in Table 1.
Table 1: Winston Tailings Sample Assay Results
| Tailings Sample ID | UTM Easting | UTM Northing | Depth of Water above sample(m) | Au(g/t) | Ag(g/t) | Zn(%) | Cu(%) | Co (ppm) | Ga (ppm) |
| F212201 | 472983 | 5424622 | 5.0 | 0.143 | 7.72 | 1.18 | 0.10 | 151.00 | 49.40 |
| F212202 | 473209 | 5423993 | 1.0 | 0.102 | 5.35 | 1.23 | 0.10 | 95.10 | 33.30 |
| F212203 | 473195 | 5424052 | 1.0 | 0.554 | 13.60 | 1.27 | 0.15 | 279.00 | 93.60 |
| F212204 | 473191 | 5424096 | 1.5 | 0.538 | 20.60 | 1.48 | 0.19 | 496.00 | 104.00 |
| F212205 | 473163 | 5424154 | 1.5 | 0.272 | 21.20 | 1.49 | 0.19 | 448.00 | 121.00 |
| F212206 | 473154 | 5424214 | 1.5 | 0.333 | 10.70 | 1.14 | 0.12 | 292.00 | 80.50 |
| F212207 | 473123 | 5424272 | 1.5 | 0.298 | 8.20 | 1.43 | 0.13 | 201.00 | 74.20 |
| F212208 | 473101 | 5424328 | 1.5 | 0.399 | 10.80 | 1.19 | 0.14 | 286.00 | 77.20 |
| F212209 | 473066 | 5424391 | 1.5 | 0.452 | 10.50 | 2.20 | 0.20 | 237.00 | 55.40 |
| F212211 | 473007 | 5424434 | 1.5 | 0.814 | 21.90 | 1.14 | 0.16 | 470.00 | 106.00 |
| F212212 | 472975 | 5424491 | 1.5 | 0.790 | 16.20 | 1.23 | 0.13 | 466.00 | 122.00 |
| F212213 | 472938 | 5424552 | 5.0 | 0.305 | 10.30 | 1.13 | 0.12 | 330.00 | 99.70 |
| F212214 | 473054 | 5424603 | 2.5 | 0.151 | 8.36 | 1.02 | 0.10 | 142.00 | 46.10 |
| F212215 | 473085 | 5424562 | 2.5 | 0.112 | 7.39 | 1.16 | 0.09 | 165.00 | 57.90 |
Table Notes: UTM Zone 16N NAD83 Datum. AGAT Laboratories analytical package method 202-552 for gold, method 201-071 for other metals.
Source: NI 43-101 Technical Report Feasibility Study for the Superior Zinc and Copper Project, 2021. Site is connected to high-voltage grid power.
Figure 1: Existing Infrastructure at Winston Tailings Storage Facility
Figure 2: Winston Tailings Sample Location Points with Gold Grade
Glossary
Fire Assay: Fire assay is a pyrometallurgical technique that uses heat and specific reagents to isolate precious metals from a sample in order to determine the precious metal content (like gold and silver) in ores and other materials.
ICP-MS: Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry that uses an inductively coupled plasma to ionize the sample. It atomizes the sample and creates atomic and small polyatomic ions, which are then detected. It is known and used for its ability to detect metals and several non-metals in liquid samples at very low concentrations.
ICP-OES: Inductively coupled plasma optical emission spectroscopy (ICP-OES), is an analytical technique used for the detection of chemical elements. It is a type of emission spectroscopy that uses the inductively coupled plasma to produce excited atoms and ions that emit electromagnetic radiation at wavelengths characteristic of a particular element.
References
1. Panther Metals PLC, announcement, Tailings Sampling Programme Underway at Winston Project, dated 15 July 2025 (https://polaris.brighterir.com/public/panther_metals/news/rns/story/w606ngw )
Competent Person Statement
Technical information in this announcement has been reviewed by Nicholas O’Reilly BSc (Hons) MSc DIC MIMMM QMR MAusIMM FGS, a director of the Company. Mr O’Reilly is principal geologist and a director of Mining Analyst Consulting Ltd. He has over 20 years’ experience in mining, exploration and development across all major commodities. As a qualified geologist, he can act as Competent Person for JORC Code and UK Listing Rules purposes.
Responsibility Statement
Darren Hazelwood, Chief Executive Officer of the Company is responsible for the release of this information.
For further information, please contact:
Panther Metals PLC:
Darren Hazelwood, Chief Executive Officer: +44(0) 1462 429 743
+44(0) 7971 957 685
Broker:
SI Capital Limited
Nick Emerson +44(0) 1438 416 500
Winston Project
The Panther Metals Winston Project, located 150km east of Thunder Bay, Ontario, Canada, is an advanced stage polymetallic zinc, copper and precious metal property comprising a high-grade critical mineral mine redevelopment and resource building opportunity. Based on a Feasibility Study published in 2021 the Project is expected to generate average life of mine (“LOM”) annual EBITDA of C$67.64 million (M) and have a pre-tax NPV8% of C$ 175.8 M and IRR of 26%, with further strong exploration potential for defining additional Mineral Resources and Mineral Reserves from the two main deposits as well as additional near-mine volcanogenic massive sulphide (“VMS”) exploration targets.
2021 Feasibility Study Headline Metrics
· NPV8%: C$175.8M pre-tax, assuming zinc priced at US$2,700/t, copper at US$7,300/t,
gold at US$1,635/oz & silver at US$21/oz. At a derisked 6% discount
Pre-tax NPV = C$213.2M.
· IRR: 26% pre-tax
· EBITDA : C$574.9M (gross), C$67.64M (annual). Gross revenue: C$983.3M
· CAPEX: C$145.1 M
· OPEX: C$65.17/t
· LOM: Initial 8.5 year life of mine, with 3.5 year pay-back period. Strong potential to
increase LOM.
· Producing an average 33.40ktpa contained zinc,1.3ktpa contained copper, 698oz recovered gold and 90.8koz recovered silver (after ramp-up), from an onsite processing facility with an annualised 326ktpa capacity.
· The unit pricing for copper, gold and silver, concentrate payable percentages and exchange rates, are positively different from 2021 in today’s dollars, providing scope for additional value uplift.
· Indicated Resource 2.07 Million Tonnes @ 18% Zn
· Volcanogenic Massive Sulphide mineralisation well understood by Panther.
· Panther plans to build value through extending the mine life utilising the Company’s strong local exploration network and leveraging institutional, governmental and critical mineral programme support.
· No name discussions in Canada have indicated strong support for this deal on an asset base previously supported by industry heavyweights, including Sprott.
· Strong prospects to increase Mineral Resources and Mineral Reserves through exploration down-dip and along strike of the current Resources.
· Zinc and Copper deemed Critical Minerals in Canada, eligible for enhanced tax-efficient flow-through funding.
· Positive First Nation engagement.
· Strong Institutional and Governmental support for future financing options.
· Existing historical tailings storage facility offers potential for near-term cash-flow subject to further studies.
Highly prospective near mine exploration targets include the Pick Lake Deposit which is not fully constrained and is considered to be open down-plunge; the Winston Lake Deposit where there are strong electromagnetic (“EM”) geophysics conductive bodies adjacent to the current Resource; and in the vicinity of historical Zenith deposit. The wider project area is relatively underexplored and there are several prospective surface zinc targets, including Anderson, Trial and Ciglen, and the VMS hosting horizons along strike strongly warranting geophysical investigation.
The 2021 Feasibility Study1 for the Winston Project detailed a strong economic case for mine redevelopment for a 1,000 tonnes per day underground operation with a net present value (NPV8%) of C$171.5M and pre-tax internal rate of return (IRR) of 26% based on an Ore Reserve of 1.96Mt @ 13.9% Zn, 0.6% Cu with significant gold and silver credits (Table 1) producing an expected 69.8 thousand tonnes per year (ktpa) of zinc concentrate and 5.3 ktpa of copper concentrate over an initial 8.5 year mine life. The Project boasts a high-grade CIM compliant Indicated Mineral Resource2 of 2.07Mt averaging 17.9% zinc, 0.8% copper, 0.4 g/t gold, and 34 g/t silver plus Inferred 0.27Mt @ 16.2% Zn, 1.0% Cu, 0.3g/t Au & 37.2g/t Ag (Table 2). Project is located only 20km from the trans-Canada highway and infrastructure including power, tailings storage facility, transport links and underground development are already in place. The previous mining operation closed in February 1999 due to very low zinc prices at the time. In total, 3.4 million tonnes grading 1.0% copper and 16% zinc was mined and processed. The total project area covers approximately 60.4km2 and comprises both patented freehold, leased and Crown-land mining claims.
Table 1: Winston Project Mineral Reserve
| Winston Project | Ore Reserve | MillionTonnes | ZincGrade | CopperGrade | GoldGrade | SilverGrade |
| Classification | (Mt) | (Zn %) | (Cu %) | (Au g/t) | (Ag g/t) | |
| Proven | – | – | – | – | – | |
| Probable | 1.96 | 13.9 | 0.6 | 0.2 | 26.2 | |
| Total | 1.96 | 13.9 | 0.6 | 0.2 | 26.2 |
Notes: JORC (2012) compliant Mineral Reserve effective date 5 July 2019. Ore Reserves are based solely on Indicated Mineral Resources and are reported above an average net smelter return (NSR) cut-off grade of US$98 /t equivalent to 5.2% Zn. 1
Table 2: Winston Project Mineral Resource Estimate at 3% Zn cut-off grade
| Resource Areas | Mineral Resource Classification | MillionTonnes | ZincGrade | CopperGrade | GoldGrade | SilverGrade |
| (Mt) | (Zn %) | (Cu %) | (Au g/t) | (Ag g/t) | ||
| PickLake | Indicated | 1.78 | 19.20 | 0.90 | 0.3 | 36.1 |
| Inferred | 0.27 | 16.40 | 1.00 | 0.3 | 38 | |
| WinstonLake | Indicated | 0.29 | 10.40 | 0.70 | 0.9 | 18.4 |
| Inferred | 0.01 | 8.90 | 0.60 | 0.5 | 11.9 | |
| Winston Project | Total Indicated | 2.07 | 17.90 | 0.80 | 0.4 | 33.6 |
| Total Inferred | 0.27 | 16.20 | 1.00 | 0.3 | 37.2 |
Notes: Effective date 15 October 2020. Stated at 3% zinc cut-off grade. Mineral Resource estimate is compliant with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”), CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions. Mineral resources which are not mineral reserves do not have demonstrated economic viability. There has been insufficient exploration to define the inferred resources tabulated above as an indicated or measured mineral resource, however, it is reasonably expected that the majority of the Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.
Technical References:
1 NI 43-101 Technical Report Feasibility Study for the Superior Zinc and Copper Project, dated 13 October 2021, prepared for Metallum Resources Inc by DRA Global (“DRA”).
2 NI 43-101 Technical Report on the Mineral Resource Estimation of the Pick Lake and Winston Lake Properties, Ontario, Canada, dated 15 October 2020, prepared for CROPS Inc. (renamed Metallum Resources Inc) by MASSA Geoservices.
Obonga Project – Expanding Canada’s Next VMS and Critical Minerals District
Panther Metals’ Obonga Project in Ontario continues to demonstrate significant potential as a leading exploration initiative targeting both base and critical minerals. Since acquiring the Obonga Greenstone Belt in July 2021, the Company has rapidly advanced five high-priority targets: Wishbone, Awkward, Survey, Ottertooth, and Silver Rim.
In June 2024, Panther secured a key Exploration Permit for the Wishbone Prospect, valid through 2027, authorizing extensive drilling and geophysical surveys. Previous campaigns confirmed compelling volcanogenic massive sulphide (VMS)-style mineralisation, highlighted by intercepts such as 27.3m of massive sulphide and 51m of sulphide-dominated mineralisation with multiple mineralised lenses. High-grade copper anomalies in lake sediment further enhance the prospectivity of this landmark target.
July 2024 saw Panther awarded an Exploration Permit for Awkward West, supporting an aggressive exploration program including up to 31 drill holes. Historic drilling here revealed notable graphite mineralisation-27.2m at 2.25% Total Graphitic Carbon (TGC) with zones exceeding 5% TGC-alongside promising signs of nickel, copper, and platinum group elements, aligning with Panther’s strategic focus on critical minerals.
Additional exploration efforts include high-resolution magnetic geophysical surveys across key prospects, optimizing drill targeting and advancing the geological model. Survey and Ottertooth remain highly prospective, with multiple magnetic and electromagnetic anomalies and historic intercepts of massive sulphides, many targets still largely untested.
Obonga’s combination of VMS-style base metals and critical mineral potential, situated in a stable and mining-friendly jurisdiction with strong infrastructure, positions Panther Metals to unlock a district-scale mineral system with significant commercial upside.
Dotted Lake Project – Hemlo-Adjacent Gold Opportunity with Growing Momentum
Panther Metals’ Dotted Lake Project, acquired in July 2020, lies just 16km from Barrick Gold’s renowned Hemlo Mine, in one of Canada’s premier gold-producing regions. The project offers a strategically located and scalable gold exploration play.
Initial soil sampling in 2021 identified numerous gold and base metal targets, and subsequent access improvements facilitated an initial drilling program that confirmed gold mineralisation with anomalous values extending along strike.
In early 2025, Panther completed a follow-up campaign featuring detailed geological mapping, trenching, and targeted diamond drilling. These efforts extended mineralisation both laterally and at depth, identified new structural controls, and reinforced the potential for a broader, high-grade gold system. Multiple zones have been prioritised for expanded drilling, underscoring Dotted Lake’s significant upside.
The project’s proximity to established infrastructure and Hemlo’s extensive mining operations, combined with robust recent results, makes Dotted Lake a key asset in Panther’s growth portfolio.
Commercial Strategy – Discovery-Driven Value Creation
Panther Metals is committed to creating substantial shareholder value through focused exploration and disciplined capital management. The Company combines deep geological expertise with an understanding of market and financing dynamics to advance high-potential projects efficiently.
With access to a global network of industry leaders and a rigorous operational focus on drilling, Panther prioritises activities that directly contribute to discovery and resource growth. The drill hole remains the ultimate validation in mineral exploration, and Panther’s strategy is to fast-track world-class targets into drill-ready assets – delivering tangible results that underpin long-term value creation for shareholders.
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