Dotted Lake: Phase 1 – 38% Magnesium Recovery
Panther Metals Plc (LON: PALM), the exploration company focused on mineral projects in Canada, is pleased to announce the encouraging results of the Phase 1 Magnesium Recovery Investigation testwork undertaken on magnesium (Mg) bearing drill core samples obtained from the Company’s Dotted Lake Project (“Dotted Lake” or the “Project”) located in Ontario, Canada.
As announced on 23 February 2026, Panther is evaluating opportunities to recover magnesium from the Mg bearing serpentinised peridotite (serpentinite) constituting the Dotted Lake ultramafic magmatic intrusive. The Company is particularly interested in environmentally neutral alternative extraction technologies capable of improving upon conventional leaching recoveries.1
Test Design Implement Solutions LLC (“TDI”) has completed a preliminary (Phase 1) metallurgical investigation on serpentine-rich ultramafic material supplied by Panther to evaluate the applicability of the Extrakt Process Solutions LLC (“Extrakt”) Extrakt™ leaching technology for magnesium extraction and to identify operating conditions capable of supporting future process development.
As well as magnesium, which is included on Canada’s official critical minerals list, Panther is targeting magmatic intrusive hosted nickel-cobalt-chromium (Ni-Co-Cr) and platinum group elements (“PGE”) at Dotted Lake. The Ni-Co-Cr and PGE were not part of the Phase 1 Mg recovery testwork. The Project is located close to trans-continental rail and road transport infrastructure on the north shore of Lake Superior in Ontario Canada and approximately 16 kilometres from the Hemlo Gold Mine which has approximately 25 Moz of historic gold production.2
Highlights
· Phase 1 recovery testwork has successfully confirmed the Dotted Lake ultramafic intrusive as a magnesium-rich serpentine feedstock with elevated concentrations of chromium, nickel, cobalt, and other critical elements that will warrant further evaluation as potential by-products in future studies.
· Phase 1 recovery tests reached approximately 38 weight % (wt.%) magnesium, significantly exceeding the silica passivation related recovery ceiling of 19-25 wt.% observed during conventional single-stage leaching. The cumulative recovery achieved in tests Exp-27A and Exp-27B reached approximately 38 wt.%, substantially exceeding the recovery limit observed during single-stage leaching.
· The work has successfully generated a baseline metal recovery and process performance data that will inform and support the design and optimisation of subsequent test phases including a Reagent Management System (“RMS”).
· Recent Test Design Implement Solutions LLC RMS testwork conducted on similar material demonstrated a magnesium concentration factor of at least 2×, providing an indication of the potential reduction in downstream processing requirements.
· The Extrakt™ leaching process demonstrated the potential to significantly increase cumulative magnesium recovery while simultaneously improving reagent efficiency and reducing operating costs.
· Although the results are highly encouraging, they remain preliminary and require confirmation through additional metallurgical testing, mass balance verification, reproducibility studies, and techno-economic evaluation, including reagent management system optimisation, before advancing to pilot-scale testing or commercial process design.
Darren Hazelwood, Chief Executive Officer commented:
“When we commissioned the Phase 1 testwork, our objective was to answer one fundamental question: ‘Can we recover the magnesium from Dotted Lake?’
The answer is ‘Yes!’. We now know that we can.
Achieving a 38 wt.% magnesium recovery at this first stage of work is an extremely exciting result for Panther. We started with a geological opportunity; we now have the initial technical validation and the experimental baseline, that the magnesium can be recovered.
Importantly, this is only Phase 1, we have successfully generated a baseline metal recovery and process performance data that will inform and support the design and optimisation of subsequent test phases.
For us, this result changes the conversation around Dotted Lake. Our focus can now begin to expand beyond simply demonstrating Mg recovery, towards understanding the potentially strategic and commercial opportunity offered by the Project.
We now have a solid platform to begin evaluating potential opportunities with relevant government bodies across North America, as well as potential end users and participants throughout the mining and critical minerals industry. Magnesium is a designated critical mineral for Canada and an important metal across automotive, aerospace, defence and advanced manufacturing. Establishing a secure North American supply chain for critical materials has become an increasingly important strategic priority for Western governments.
Dotted Lake is a substantial ultramafic system, and we are only beginning to understand its potential. Demonstrating 38 wt.% Mg recovery gives us a strong platform from which to continue those conversations whilst we advance the test work.
The Phase 1 result is a significant milestone for Dotted Lake, and for Panther, and I am incredibly excited about where we take this next.”
Background
The previously reported results of the Dotted Lake 2024 five hole exploration drill and soil geochemical sampling programme confirmed the Project hosts multiple styles of mineralisation, including ultramafic-hosted chromium, nickel, platinum group elements and magnesium, and structurally controlled gold, and zinc potential. The drilling confirmed the Dotted Lake ultramafic magmatic intrusive to be a magnesium (Mg) bearing serpentinised peridotite (serpentinite). 3,4,5
The Phase 1 recovery testwork is the first in a series of potential investigations to evaluate recovery of magnesium from the Dotted Lake serpentinite intrusive, with particular emphasis on the evaluation of alternative extraction technologies capable of improving upon conventional leaching recoveries, specifically by using Extrakt’s proprietary extraction technology. The Phase 1 work has successfully achieved the objective of generating baseline metal recovery and process performance data that will inform and support the design and optimisation of subsequent test phases.
Panther submitted 134kg of crushed serpentinite drill core, from the 2024 drilling programme, for the Phase 1 magnesium investigatory test work by Test Design Implement Solutions LLC (“TDI”). TDI is one of the approved laboratories for testing of the Extrakt™ leaching technologies.
The submitted material comprised 60 samples, selected from drillholes DL24-002 and DL24-004. The 60 samples were combined into three composite samples, with the compositing strategy designed to account for down-hole stratigraphy, ensuring that the resulting composites are representative of the vertical geological sequence encountered at each sampling location. This approach was adopted to support accurate geological interpretation and to ensure that any lithological or mineralogical variations with depth are appropriately captured in the test samples.
The assay data for the 60 samples indicated that the material is a chemically homogeneous, serpentine-dominated ultramafic rock enriched in critical minerals including magnesium (approximately 20 wt.% Mg), with elevated concentrations of iron (7-10 wt.% Fe), chromium (2,000 to >10,000 ppm), nickel (700-2,500 ppm), and cobalt (130-150 ppm). Calcium and aluminium contents were relatively low, suggesting limited carbonate and feldspathic gangue. Minor concentrations of scandium, zirconium, yttrium, rubidium, and rare earth elements may warrant further evaluation depending on the overall process economics.6
A video illustrating the size and morphology of the Dotted Lake ultramafic magmatic intrusive is available to view on the Panther Metals PLC YouTube channel7 at https://youtu.be/B90KUU6Kk98?si=4WhxNwzU8IKYF0bC
Dotted Lake Magnesium-Bearing Ultramafic Drill Intersections
Three drill holes from Panther’s 2024 diamond drilling programme, DL24-002, DL24-003 & DL24-004, intersected the serpentinite (Figure 1 & 2) showing distinct magnesium bearing ultramafic layering, with indications of strong potential to host massive sulphide mineralisation.
Drill core samples from DL24-002, DL24-003 & DL24-004 were submitted to TDI for the Phase 1 Mg recovery testwork. The serpentinite downhole drillhole intersections included:
· DL24-002 intersected a 214.7m wide open-ended zone of magnesium (Mg) peridotite derived serpentinite grading up to 21.7% Mg (36% MgO) with platinum (Pt) and palladium (Pd), nickel (Ni), and silver (Ag), and up to 5.47% chromium (Cr) between 113.3m downhole to end of hole at 328m, with
o 36.3m @ 18.8 % Mg (31.2% MgO), 0.13 % Ni, 0.01 g/t Pt, 0.02 g/t Pd & 0.43 % Cr from 216.0m;
o 7.5m @ 20.0 % Mg (33.1% MgO), 0.20 % Ni, 0.02 g/t Pt, 0.04 g/t Pd & 0.49 % Cr from 258.5m;
o 12.0m @ 19.7 % Mg (32.5% MgO), 0.18 % Ni, 0.01 g/t Pt, 0.02 g/t Pd & 0.63 % Cr from 304.0m.
· DL24-003 intersected serpentinite with:
o 129.0m @ 14.4 % Mg (23.9% MgO), 0.09 % Ni, 0.01 g/t Pt, 0.02 g/t Pd, 0.37 % Cr from 172.0m and up to 6.65% Cr.
· DL24-004 intersected serpentinite ranging up to 20.6% Mg (34% MgO) and up to 1.90% Cr with:
o 94.4m @ 17.7 % Mg (29% MgO), 0.12 % Ni, 0.01 g/t Pt, 0.02 g/t Pd, 0.46 % Cr & from 152.6m, including 4.6m @ 0.17 % Ni, 0.03 g/t Pt, 0.09 g/t Pd & 1.13 % Cr from 196.7m
Figure 1: Plan view of modelled Dotted Lake Ultramafic Intrusive Body showing location of Panther diamond drillholes (based on geophysical inversion model, core of intrusive shaded purple).
Figure 2: Oblique three-dimensional view of modelled Dotted Lake Ultramafic Intrusive Body showing location of Panther diamond drillholes (based on geophysical inversion model, core of intrusive shaded purple). For relative scale see Figure 1.
Qualified Person Statement
Technical information in this announcement has been prepared by Nicholas O’Reilly BSc (Hons) MSc DIC MIMMM (QMR) MAusIMM FGS, a director of the Company. He has over 20 years’ experience in mining, exploration and development across all major commodities and is a Qualified Person (“QP”) as defined in NI 43-101 and is the Competent Person for UK Listing Rules purposes.
References
1. Panther Metals PLC, announcement, Dotted Lake Project: Magnesium Recovery Testwork, dated 23 February 2026
( https://polaris.brighterir.com/public/panther_metals/news/rns/story/w0n278r )
2. Hemlo Mining Corp. website states the Hemlo Mine’s ‘consolidated property package covers more than 45,000 hectares and multiple mining leases, bringing together the historic David Bell, Golden Giant and Williams Lake mines within one world-class camp that has produced roughly 25 million ounces of gold to date’ ( https://www.hemlomining.com/#hemlo-gold-mine )
3. Panther Metals PLC, announcement, Dotted Lake Project: Update, dated 23 May 2025
(https://polaris.brighterir.com/public/panther_metals/news/rns/story/rgvg8vr )
4. Panther Metals PLC, announcement, Dotted Lake: Drilling Results, Assay Results Confirm Magnesium Rich Serpentinite, Wide Drill Intercepts Continue to Reinforce Ultramafic Intrusive Fertility, dated 21 March 2025
( https://polaris.brighterir.com/public/panther_metals/news/rns/story/x2pqjlw )
5. Panther Metals PLC, announcement, Dotted Lake: Drilling Results, Assay Results Confirm Magnesium Rich Serpentinite, Intrusive Layering Shows Grades Strengthening with Depth, dated 25 March 2025
( https://polaris.brighterir.com/public/panther_metals/news/rns/story/w0kqkpr )
6. Government of Canada website: Canada’s critical minerals.
( https://www.canada.ca/en/campaign/critical-minerals-in-canada/critical-minerals-an-opportunity-for-canada.html )
7. Panther Metals PLC, YouTube channel video: Dotted Lake Ultramafic Intrusion: Magnesium-Rich Serpentinised Peridotite
( https://www.youtube.com/watch?v=B90KUU6Kk98 )
For further information, please contact:
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Panther Metals PLC: Darren Hazelwood, Chief Executive Officer: |
+44 (0)1462 429 743 +44 (0)7971 957 685 |
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