Middle Island Resources has significantly extended the polymetallic soil anomaly at its Bobija Project in Serbia, uncovering a major silver-lead-zinc-antimony system consistent with a carbonate replacement deposit. High-grade assays and visible stibnite mineralisation highlight the project's growing potential near an operating mine.
- Polymetallic soil anomalies expanded over ~6km strike
- High-grade assays up to 12.0g/t silver and 2.85% antimony
- Visible stibnite confirms robust antimony mineralisation
- System remains open with further soil sampling planned
- Located 20km from operating Veliki Majdan mine
Major Polymetallic System Emerges at Bobija
Middle Island Resources (ASX:MDI) has revealed a significant expansion of polymetallic mineralisation at its Bobija Project in Serbia, with follow-up soil sampling extending the footprint of the Tisovik target to cover multiple high-priority zones across a roughly 6-kilometre strike length. The latest assays report robust silver, lead, zinc, and antimony anomalism, with soil samples returning up to 7.1g/t silver, 4,685ppm lead, 969ppm zinc, and 1,049ppm antimony. Rock chip and grab samples have confirmed high-grade mineralisation, including assays up to 12.0g/t silver and 2.85% antimony, alongside visible stibnite crystals at the Red Rock prospect.
The polymetallic assemblage aligns with a carbonate replacement deposit (CRD) style, a globally significant mineral system known for hosting large, high-grade ore bodies. This discovery is particularly notable given the project's proximity, just 20 kilometres, to the operating Veliki Majdan silver-lead-zinc mine, suggesting strong regional potential.
Expanding Soil Anomalies and Confirmatory Rock Sampling
The expanded soil sampling program, comprising 82 samples on widely spaced north-south lines, has notably extended the Kozila anomaly by 300 metres to the north, now covering an area of approximately 2 square kilometres. Multiple target zones, including Tisovik, Red Rock, and Kozila, exhibit coherent silver-lead-zinc-antimony anomalism, underscoring the scale and continuity of the mineralised system. The soil anomalies remain open-ended, particularly to the north where prospective limestone units continue beyond current sampling limits.
Complementing the soil results, 20 rock chip and grab samples from Red Rock and Kozila returned highly anomalous assays, with some samples featuring coarse visible stibnite crystals, a key indicator of antimony mineralisation. At Kozila, rock chips confirmed outcropping silver, lead, and zinc mineralisation, including a standout 12.0g/t silver and 5,244ppm lead result. Field mapping also uncovered a previously undocumented exploration adit near Kozila, further evidencing the area's underexplored nature despite historic workings.
Strategic Importance of Antimony and Next Exploration Steps
Middle Island's CEO Peter Spiers highlighted the significance of the antimony findings, noting the growing strategic importance of this metal globally. The presence of stibnite mineralisation alongside silver, lead, and zinc strengthens the case for a substantial polymetallic CRD system at Bobija. The company plans to extend soil sampling northwards into an 8-square-kilometre untested area, aiming to delineate the full extent of the mineralised system. This will be followed by infill soil sampling, gravity surveys to identify dense sulphide bodies, trenching, and drill testing.
These soil programs are running in parallel with staged drilling campaigns at the Bobija Mine area, with assay results from the recently completed Phase 2 reverse circulation (RC) drilling eagerly awaited. The continuation of drilling and geochemical programs is expected to refine target zones and advance the understanding of this emerging polymetallic system.
Bobija Project's Place in a World-Class Mineral Province
The Bobija Project sits within the Western Tethyan Mineral Province, a world-class geological setting hosting giant copper, gold, and silver deposits such as Zijin Mining's Cukaru Peki and Rio Tinto's Jadar projects. Middle Island's Serbian portfolio spans 14 licences covering approximately 620 square kilometres, including the Bobija, Timok, and Priboj project areas. The recent expansion of polymetallic targets at Bobija builds on the company's earlier Phase 2 drilling completed at Bobija, which confirmed mineralisation continuity beneath the historic open pit.
Further, the company's accelerated exploration efforts in 2026, including new drilling and soil sampling campaigns, are designed to capitalise on the promising late 2025 results from Bobija and other targets. This momentum is complemented by discoveries at other Serbian projects, such as the gold system at Zabrnjica within the Priboj Project, which adds depth to Middle Island's growing portfolio of underexplored mineral systems in the region.
Bottom Line?
The expanded polymetallic anomalies and high-grade antimony at Bobija position Middle Island for a potentially significant discovery, but pending drilling assays will be critical to validate the system's scale and economic viability.
Questions in the middle?
- Will the pending Phase 2 drilling assays confirm the continuity and grade of the polymetallic system?
- How extensive is the antimony mineralisation, and could it become a strategic metal focus for the project?
- What impact will further soil sampling and geophysical surveys have on refining drill targets in the largely unexplored northern areas?