Tannenberg Copper Project

In December 2025, GreenX completed the acquisition of 90% of Group 11 Exploration GmbH, the company that holds the Tannenberg exploration licences. Tannenberg is a brownfield project targeting sediment-hosted (Kupferschiefer-type) copper-silver deposits. The style of mineralisation is directly comparable to the Kupferschiefer deposits of Poland, where KGHM operates one of the world’s largest copper-silver mining districts, producing approximately 730,000 tonnes of copper and 43 million ounces of silver in 2024.

The Tannenberg Copper Project, covering 1,900 km² in the State of Hesse, central Germany, is emerging as a strategically timed opportunity. Located within a historically productive mining region, Tannenberg offers scale, geological pedigree, and a low sovereign risk profile. GreenX views the project as well aligned with EU and German policy priorities and intends to position Tannenberg as a future contributor to Europe’s critical mineral resilience.

Prior to closure in the 1950s, the Richelsdorf mines produced approximately 416,500 t of copper and 33.7 Moz of silver from Kupferschiefer-type deposits. These shallow underground workings were accessed from surface outcrops.

The Project area also hosts multiple historic drill intercepts over the 14 km-long Richelsdorf Dome target, including:

• 2.1 m @ 2.7% Cu and 48 g/t Ag from 365.48 m
• 1.5 m @ 3.7% Cu and 33 g/t Ag from 209.50 m
• 2.5 m @ 1.8% Cu and 19 g/t Ag from 339.5 m (south-west of licence)
• 2.0 m @ 1.6% Cu and 19 g/t Ag from 268 m (north-east of licence)

Kupferschiefer-style deposits are a prolific subtype of sediment-hosted copper deposit, forming the second most important source of global copper production and reserves. They have been mined historically in Germany and activity continues in Poland, where KGHM produced 730 kt of copper and 43 Moz of silver in 2024, ranking as the world’s 9th-largest copper and 2nd-largest silver producer. Lumina Metals (TSE: LMCU) is advancing the Nowa Sól copper-silver project within the same Kupferschiefer belt in Poland.

Germany has a long mining tradition and remains a significant jurisdiction, with K+S operating close to the Tannenberg licence area in the State of Hesse.

During 2025, GreenX recovered a major historical database comprising 95 drillholes from 1930s exploration (Figure 3) and 47 post-1970s drill cores (Figure 4), representing over €25 million in exploration value and more than a decade of work.

The 95-hole drilling campaign, completed between 1935 and 1938, formed the geological basis for three Kupferschiefer copper mines within the Tannenberg licence area: Reichenberg, Wolfsberg and Schnepfenbusch. GreenX has digitised and integrated this drillhole database into its geological models.

The 1940 historical estimate, produced by Mansfeldsche Kupferschieferbergbau AG, is based on a spatially relevant subset of 18 holes from the 95-hole database and established 728,000 tonnes of contained copper at an average grade of 2.6% copper (in the narrow Kupferschiefer shale only) between the Wolfsberg and Schnepfenbusch mines in the north and the Ronshausen area in the south (Figure 5). A later historical estimate from 1984 was produced by St Joe Explorations GmbH, based on limited drilling between 1980 and 1984. The St Joe historical work estimated 169,000 tonnes of contained copper and 6.5 million ounces of contained silver. St Joe assayed wider intersections and found that the mineralisation was up to 3.45 m thick.

GreenX logged, sampled and assayed a total of 4,389 m of archived core and took 2,368 new samples, as part of a modern, quality-assured programme that also included hyperspectral scanning and petrophysical analysis. Historical sampling was generally limited to a narrow 5 m interval around the Kupferschiefer shale; however, copper mineralisation can extend up to 30 m above and 60 m below this horizon within the surrounding limestone and sandstone units, leaving substantial areas untested.

Initial assay results from the first six archived holes confirm this broader mineralisation model, with widths of 1.0 to 3.7 m that significantly exceed those used in the 1940 historical estimate. Intercepts include 1.5 m at 2.7% Cu and 55 g/t Ag (Ro23) and 3.7 m at 1.2% Cu and 17 g/t Ag (Ro15). These outcomes validate the historical grades, demonstrate the presence of thicker mineralised intervals, and reinforce GreenX’s exploration model that mineralisation extends well beyond the shale, consistent with KGHM’s Kupferschiefer operations in Poland.