Winston: Gold & Critical Mineral Update

Evaluation and Permitting Workstreams Commencing

Panther Metals Plc (LSE: PALM), the exploration company focused on mineral projects in Canada, is delighted to provide an update outlining the commencement of a series of workstreams to quantify and evaluate the contained high-grade gold (Au), gallium (Ga), silver (Ag), zinc (Zn), copper (Cu) and cobalt (Co) and other recoverable minerals located within the historic Winston Lake Mine tailings storage facility ("TSF") in Ontario, Canada.

As announced 31 July 2025, the assay results from the recent initial sampling programme, comprising a 680m longitudinal transept across the 1 km long TSF (Figures 1 & 2), returned high grade gold up to 0.814 g/t Au, with up to 21.9 g/t Ag, 2.20% Zn, 0.20 % Cu, 496 ppm Co and 122 ppm Ga as outlined in Table 1. These results strongly support 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.1, 2

Panther is pleased to announce an exciting programme which includes the following workstreams:

1. Historical Assessment: A review of historical mine tailings production reconciliation and volumetric accounting records has commenced. First Quantum Minerals has provided the Company with access to the Winston Lake Mine historical reports outlining processing feed head grade, grades recovered to the zinc and copper concentrates and the grades of materials reporting to the tailings. This data is supplemented by access to First Quantum personnel involved with maintaining and monitoring the TSF and who were involved with production when the mine was active. In addition, further hardcopy records, plans and maps are available in the archives onsite. The review of this documentation and calculations, together with the historical density records, will help establish a baseline for the development of a working economic assessment model and will feed into the Technical Studies and Permitting workstreams outlined below.

2. Technical Studies - Appointment of Specialists: The Company has undertaken a streamlined procurement process and is now agreeing the relevant scope of works with the preferred drilling and geological contractors, tailings and mineral processing specialists ahead of formal appointment. The contractors and specialists will be involved with the design and execution of a number of key studies including the metallurgical sampling programme, metallurgical characterisation and deportment studies, resource calculations, and work to determine optimal reprocessing, commodity capture and tailings retreatment routes as well as the associated bench testwork and environmental planning. Further details will be announced in due course.

3. Permitting Process: In conjunction with the technical studies, in order optimise the timeline to potential production, the Company has commenced the necessary engagement with the Ontario Ministry of Energy and Mines with the Ministry of Northern Development, Mines, Natural Resources and Forestry to map out the permitting path-way to reprocess the tailings from the Winston brownfield mine site. The permitting workstream centres around the new Recovery of Minerals regulation (Ontario Regulation 463/24 under the Mining Act) which came into effect on 1 July 2025. A Mineral Recovery Permit authorises the extraction of residual minerals from tailings and other mine wastes on existing or abandoned mine sites where previous mining activities have taken place. The regulation provides a streamlined permitting process that will allow recovery of minerals activities to occur faster without requiring a closure plan. 3

• Ancillary Critical Minerals: Whilst Panther currently views gold, silver, zinc and copper as the primary target commodities for the envisaged tailings reprocessing, as an integral part of the above workstreams the Company will be undertaking a review of the potential value attributable to other recoverable critical mineral components in the tailings such as the gallium (Ga), germanium (Ge), indium (In) and manganese (Mn) which are all linked to the zinc mineral sphalerite, and which are sought by the electronics and renewable energy industries.

Darren Hazelwood, Chief Executive Officer, commented:

"Since announcing the exciting sample assay results from the Winston Lake Mine tailings storage facility, we have been very busy setting out and commencing a series of workstreams which are designed to fast-track the assessment and build a robust economic case to reprocess and extract value from the tailings.

The assay results strongly supported the initiation of the metallurgical sampling and resource determination work which will feed into the mineral processing studies required to determine the most economic and environmentally sensitive route for extracting the precious metals and critical minerals from the tailings.

Last month the Government of Ontario instated a new regulatory regime designed to streamline the tailing reprocessing permitting process that will allow recovery of minerals activities to occur faster without requiring a closure plan. Panther have embarked on the permitting process which will be run in tandem with the technical studies, in order to shorten our timeline to projected cashflow.

In layperson's terms the planned workstreams are designed to provide the necessary numbers to quantify the economic value recoverable from the tailings and to constrain the costs involved with bringing the tailing re-processing into production and generating significant cashflow to advance the business.

We look forward to providing further updates in due course."

Background

As announced 15 July 2025 and 31 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, 2

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

Table Notes: UTM Zone 16N NAD83 Datum. AGAT Laboratories analytical package method 202-552 for gold, method 201-071 for other metals.

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

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
• Indicated Resource 2.07 Million Tonnes @ 18% Zn
• Volcanogenic Massive Sulphide mineralisation well understood by Panther.
• Positive First Nation engagement.
• Strong Institutional and Governmental support for future financing options.

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

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

Technical References:

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