Study Finds Tannenberg Consistent with Polish Mine

NEWS RELEASE  17 JUNE 2026

MINERALOGY STUDY CONFIRMS TANNENBERG CONSISTENT WITH POLISH KUPFERSCHIEFER MINES

HIGHLIGHTS

·    Tannenberg mineralisation consistent with producing Polish Kupferschiefer copper-silver mines. Review by independent metallurgist from MSA Mining Consulting UK confirms potential suitability for a conventional flotation-based processing route, as used at KGHM's (WSE:KGH) long-running operations and planned for Lumina Metals' (TSE: LMCU) Nowa Sól project

·    Established Kupferschiefer flowsheet provides baseline processing route for Tannenberg. KGHM's operations process 30 Mtpa at 1.6% Cu and 45 g/t Ag, achieving 89% copper and 86% silver aggregate recovery from a blended feed of Kupferschiefer shale, sandstone and carbonate-hosted mineralisation using crushing, two-stage grinding, rougher flotation, fine regrinding and multi-stage cleaning

·    Modern processing technologies offer potential to enhance recoveries. Advances, including high-pressure grinding rolls (HPGR), fine-particle flotation systems and advanced reagent schemes, will be investigated, with potential to improve liberation and recovery of fine-grained copper sulphides relative to legacy flowsheets developed decades ago for KGHM

·    Mineralogy study completed by SGS Lakefield on ten drill core samples. This study shows that the copper is predominantly hosted in chalcocite with additional bornite, chalcopyrite and covellite, typical of Kupferschiefer deposits

·    Bi-modal copper sulphide grain size distribution identified, with both coarse (>25-30 µm) and very fine disseminated material (<5-10 µm), informing comminution and flotation circuit design

·    Historical extraction at the Tannenberg Project materially de-risks metallurgy. The Tannenberg mines produced 416,500 tonnes of copper and 33.7 Moz of silver predominantly during the 1930's - 50's, when mineral processing technology was not as advanced as it is in modern times 

·    Supports progression to scoping-level metallurgical testwork on representative samples of each lithology to seek to confirm initial mineralogical findings, assess comminution characteristics and evaluate flotation performance

GreenX Metals Limited (ASX:GRX, LSE:GRX, GPW:GRX, Germany-FSE:A3C9JR) (GreenX or the Company) is pleased to announce that it has completed an early-stage mineralogy and processing study for its Tannenberg Copper Project (Tannenberg or the Project) in Germany. The mineralogy study was completed by SGS Canada Inc. at its Lakefield Ontario facility (SGS Lakefield). It was followed by an independent metallurgical review undertaken by MSA Mining Consulting UK Ltd (MSA-UK) through Principal Associate Metallurgist, Mr Gordon Cunningham. The review has benchmarked Tannenberg against operating and development Kupferschiefer mines in Poland, confirming that copper mineralisation at Tannenberg is consistent with copper-silver deposits in the region and is considered amenable to conventional flotation-based processing methods.

GreenX's Chief Executive Officer, Mr Ben Stoikovich, commented: "This mineralogy study confirms that the copper is contained in the same size and style of minerals as the producing Polish Kupferschiefer mines. This independent review supports a potential conventional flotation processing route, which reduces technical risk at this early stage. This gives us confidence that Tannenberg appears to have the right ingredients to follow a proven development pathway, and we will advance metallurgical test work to unlock that potential."

TYPICAL PROCESSING METHODS - KUPFERSCHIEFER OPERATIONS (KGHM AND LUMINA METALS ANALOGUES)

The sediment-hosted (Kupferschiefer) copper-silver deposits in Poland provide a well-established processing analogue for GreenX's Tannenberg Project, with both long-running operations at KGHM and a recent Preliminary Economic Assessment (PEA) for Lumina Metals' Nowa Sól Project applying similar flotation-based processing routes with selective regrinding.

At KGHM's operations, approximately 30 Mtpa of ore is treated from the Kupferschiefer sequence at an average feed grade of around 1.6% copper and 45 g/t silver. The plant processes a blended feed comprising Kupferschiefer shale, sandstone and carbonate-hosted mineralisation. Processing is based on a conventional sulphide flotation flowsheet, starting with crushing followed by two-stage grinding (rod-ball or ball-ball milling) to a primary grind size of approximately 75 µm (Source: KGHM, Micon, 2013 (see Appendix 2)).

Following grinding, the slurry is treated through flotation circuits consisting of two stages of rougher flotation. The rougher concentrate is then reground to a much finer size, typically less than 20 µm, before passing through multi-stage cleaning circuits. This combination of initial grinding and subsequent fine regrinding is critical to liberate the fine-grained copper sulphide minerals characteristic of Kupferschiefer deposits. The process produces a copper concentrate grading approximately 23% Cu and containing significant silver, with typical metallurgical performance of around 89% copper recovery and 86% silver recovery. The final concentrate is then transported to smelting and refining facilities, where copper metal is produced and silver and other by-products are recovered.

The PEA stage Nowa Sól Cu-Ag Project, owned by Lumina Metals and located within the same Kupferschiefer belt as both Tannenberg and the KGHM mines, provides a modern comparison and follows a similar processing philosophy (Source: Lumina Metals, Micon, 2026 (see Appendix 2)). The proposed flowsheet incorporates semi-autogenous grinding (SAG) with ball milling and pebble crushing, targeting a primary grind size of approximately 60 µm, followed by flotation processing. As with KGHM, the flotation circuit includes two stages of rougher flotation, with the rougher concentrate subjected to fine regrinding (to approximately 11 µm) and multiple cleaning stages to improve concentrate grade and recovery.

The Nowa Sól flowsheet is designed to produce a copper concentrate grading greater than 26% Cu, with strong silver credits (in excess of 1,200 g/t Ag), and expected recoveries of more than 88% for copper and approximately 86% for silver. The final concentrate is planned to be thickened and filtered prior to sale.

Together, these operating and development analogues demonstrate that Kupferschiefer mineralisation can be successfully processed using conventional flotation circuits that incorporate fine grinding, concentrate regrinding and multi-stage cleaning. They also highlight the importance of achieving sufficient liberation of fine-grained copper minerals, a key factor in maximising recovery and concentrate quality in this style of deposit. In the cases of both KGHM and Lumina, there remains a strong opportunity to refine and optimise the flowsheets. In KGHM's case, the plant was built many decades ago, and the Lumina flowsheet used a limited amount of sample material.

COMPARISON OF TANNENBERG COPPER-SILVER MINERALISATION WITH POLISH ANALOGUES

The new mineralogical work was completed by SGS Lakefield on ten selected historical drill core samples distributed throughout the mineralised area (Figure 1). The analysis covered three types of mineralisation, including shale, sandstone and carbonate (Figure 2) and provided confirmation of the deportment of the Tannenberg mineralisation, allowing for an important comparison to the Polish deposits. The study utilised TESCAN Integrated Mineral Analyzer (TIMA) and Scanning Electron Microscopy (SEM) techniques to characterise mineral composition, grain size and liberation behaviour.

The results indicate that copper mineralisation is dominated by chalcocite, with additional contributions from bornite, chalcopyrite and covellite, together with minor pyrite, galena and sphalerite. Copper occurs across Kupferschiefer shale, sandstone and carbonate lithologies, with the shale generally hosting the highest grades.

Figure 1: Map showing location of drill holes, indicating those used in the mineralogy study.

A key outcome of the study is the identification of a distinctly bi-modal grain size distribution of copper sulphides, with both coarse particles (>25-30 µm) and very fine disseminated material (<5-10 µm) present within the host rocks. This fine-grained component is pervasive, with all analysed sections containing copper mineralisation below 5 µm. The presence of this bi-modal distribution is considered a critical factor influencing comminution requirements, flotation performance and overall metallurgical recovery.

When compared to Polish Kupferschiefer operations and development projects, the Tannenberg mineralisation shows strong similarities in grain-size distribution. The presence of fine and disseminated sulphide mineralisation is consistent with observations from these analogue deposits, where fine grinding and regrinding are required to achieve adequate liberation.

Figure 2: Copper sulphide gangue mineral association images for the ten samples which formed part of the study. The width of each image is 1.5mm.

Based on these similarities, conventional flotation processing is considered an appropriate baseline metallurgical approach for Tannenberg. The Polish analogues demonstrate that crushing, primary grinding, flotation, concentrate regrinding and multi-stage cleaning can achieve strong recoveries of copper and silver from Kupferschiefer ores. As with all such operations, the bi-modal grain size distribution identified at Tannenberg suggests that particular attention will need to be given to comminution strategy, including the potential requirement for finer grinding to effectively liberate ultra-fine copper minerals.

The mineralogical data also indicates the presence of organic carbon and minor deleterious elements, which may report to concentrate and influence product quality. As a result, future metallurgical testwork will evaluate additional processing steps, such as carbon pre-flotation or specialised reagent schemes, to optimise concentrate grade and marketability.

The Competent Person and independent metallurgical consultant, Mr Cunningham from MSA-UK, has concluded that the Tannenberg mineralisation is materially similar to Polish analogue ores. The Competent Person considers that the Tannenberg mineralisation is potentially well suited to a flotation-based processing flowsheet and that, subject to further test work, metallurgical recoveries are comparable to, or potentially better than the ~89% Cu and ~86% Ag recoveries reported from Polish mines may be achievable at Tannenberg. The Competent Person also considers that the Project may potentially produce a copper-silver concentrate of a type that could have strong market acceptance. The Competent Person has concluded, with reasonable confidence, that the following material factors support this assessment, subject to further test work:

·      This new mineralogy study includes TIMA and SEM analysis conducted on 10 samples from four drill holes, which are considered representative of the Tannenberg mineralisation. The selected drill holes provide good spatial coverage of the target mineralisation, as shown in Figure 1.

·      The Tannenberg mineralisation is interpreted to have formed through the same genetic process as the Polish analogue ores, with all projects existing on the same structure and mineral system, the Mid-European Crystalline Zone (please refer to GreenX's announcement dated 9 September 2025).

·      Copper and silver ore-mineral grain size, host mineral associations and other deportment characteristics at Tannenberg have been found to be materially similar to the published data from the Polish analogue ores. These fundamental technical characteristics are key to determining metallurgical recovery.

·      Both copper and silver were historically extracted at the Tannenberg Project through mining activities undertaken up to the 1950's.

·      The metallurgical recoveries referenced above are consistent with the 2013 Technical Report prepared by Micron International Limited, an independent consultant to KGHM (Refer to Appendix 2).

·      Modern developments in copper processing technologies may provide opportunities to improve overall metallurgical recoveries relative to the KGHM mines, which were constructed in the 1960s.

This initial mineralogical assessment at Tannenberg also highlights the importance of detailed metallurgical testwork to optimise grind size, concentrate quality and recovery for the Project. The shallow depth of the Tannenberg Project, with the existence of spoil heaps and potentially accessible old workings will facilitate metallurgical test work being conducted during early project study phases.

RECENT DEVELOPMENTS IN COPPER PROCESSING TECHNOLOGIES

While Kupferschiefer deposits in Poland have been processed for decades using conventional flotation circuits, more recent technological developments offer opportunities to enhance metallurgical performance.

Advances in comminution technologies, such as HPGR, can improve the liberation of fine-grained copper minerals by breaking ore along natural grain boundaries. This is particularly important for Kupferschiefer mineralisation, where a significant portion of copper occurs in very fine particles.

In addition, modern flotation technologies and specialised fine-particle recovery systems can improve recovery of ultra-fine sulphide minerals, while advanced reagent schemes and pre-treatment steps, such as carbon pre-flotation, may further enhance concentrate grade.

These developments indicate that modern flowsheets have the potential to achieve improved copper and silver recoveries compared to historic operations, particularly for fine-grained Kupferschiefer ores.

Upcoming Work Programs

In addition to the ongoing exploration activities, GreenX will advance the next stage of processing work and focus on scoping-level metallurgical test work using representative samples collected from the key mineralised lithologies. This program will be designed to confirm the initial mineralogical findings, assess comminution characteristics and evaluate flotation performance, including recovery, concentrate grade and reagent selection.

Results from this test work will be used to develop a preliminary metallurgical flowsheet for the Tannenberg Project. This flowsheet will provide the basis for subsequent, more advanced metallurgical programs, including variability testing, optimisation of grind size and flotation conditions, and detailed assessment of concentrate quality and processing performance.

ENQUIRIES

Competent Persons Statement (Exploration Results)

The information in this announcement that relates to Exploration Results is based on information compiled by Dr Matthew Jackson, a Competent Person who is a Member of the Australasian Institute of Mining and Metallurgy. Dr Jackson is a Technical Consultant for GreenX and is a holder of unlisted options in the Company. Dr Jackson has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken, to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Dr Jackson consents to the inclusion in this announcement of the matters based on his information in the form and context in which it appears.

Competent Persons Statement (metallurgy MINERALOGY STUDY)

The information in this announcement that relates to Exploration Results (metallurgy mineralogy study) is based on information compiled by Mr Gordon Cunningham, a Competent Person who is a Member of the Engineering Council of South Africa and a Fellow of the South African Institute of Mining and Metallurgy, a Recognised Professional Organisation included in a list promulgated by ASX from time to time. Mr Cunningham is a Technical Consultant for MSA Mining Consulting UK Ltd. Mr Cunningham has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Mr Cunningham consents to the inclusion in this announcement of the matters based on his information in the form and context in which it appears.

Forward Looking Statements

This release may include forward-looking statements, which may be identified by words such as "expects", "anticipates", "believes", "projects", "plans", and similar expressions. These forward-looking statements are based on GreenX's expectations and beliefs concerning future events. Forward looking statements are necessarily subject to risks, uncertainties and other factors, many of which are outside the control of GreenX, which could cause actual results to differ materially from such statements. There can be no assurance that forward-looking statements will prove to be correct. GreenX makes no undertaking to subsequently update or revise the forward-looking statements made in this release to reflect the circumstances or events after the date of that release.

The information contained within this announcement is deemed to constitute inside information as stipulated under the Regulation 2014/596/EU which is part of domestic law pursuant to the Market Abuse (Amendment) (EU Exit) Regulations (SI 2019/310) ("UK MAR"). By the publication of this announcement via a Regulatory Information Service, this inside information (as defined in UK MAR) is now considered to be in the public domain.

REFERENCES AND SOURCES

Please refer to Appendix 2 below.

Appendix 1: Exploration Results and JORC Tables

Table 1: Historical drill hole information (used for process mineralogy study)

Note: Coordinates are DHDN / 3-degree Gauss-Kruger zone 4.

JORC Code, 2012 Edition - Table 1 Report

Section 1 Sampling Techniques and Data

(Criteria in this section apply to all succeeding sections.)

Section 2 Reporting of Exploration Results

(Criteria in the preceding section also apply to this section.)

APPENDIX 2: Company Specific Sources