Australian-listed explorer Middle Island Resources says it has expanded its polymetallic discovery footprint at the Bobija Project in western Serbia following new soil and rock-chip sampling. The company reported results from the Tisovik target area that indicate a silver-lead-zinc-antimony mineralized system. It is described as extending across approximately six kilometers of strike length.
The sampling program also supports Middle Island’s interpretation that the project may host a carbonate replacement deposit (CRD)-style mineral system. CRD systems are associated with large polymetallic ore bodies, according to the company’s stated geological framework. The latest results were released alongside the broader update on the project’s exploration targets.
Tisovik sampling highlights silver, lead and antimony anomalies
Middle Island said the strongest antimony results came from rock-chip samples, including values up to 28,500 ppm antimony (2.85% Sb). The same rock-chip results included silver grades reaching 12 g/t Ag and lead values above 5,200 ppm Pb. Soil sampling returned elevated anomalies across silver, lead, zinc and antimony.
The company cited soil results including 7.1 g/t silver, 4,685 ppm lead, 969 ppm zinc and 1,049 ppm antimony. Middle Island did not describe any JORC-compliant resource estimate in the update. The focus remained on expanding the known footprint through additional sampling at the Tisovik area.
Mineralized system remains open; additional work planned
Middle Island stated that the mineralized system remains open in multiple directions, with particular emphasis on the northern extent. It said prospective limestone host rocks continue into largely unexplored terrain toward the north. The company plans further exploration over an untested area of approximately 8 km² within the broader Bobija license package.
The update places the Bobija Project within a historically productive mining district about 20 kilometers from the operating Veliki Majdan silver-lead-zinc mine. Middle Island’s geological model centers on carbonate replacement deposits formed by mineral-rich hydrothermal fluids replacing limestone or other carbonate host rocks. The company linked CRD systems to strong vertical continuity in global examples of silver, lead and zinc mineralization.
Interconnected targets include Tisovik, Red Rock and Kozila
Middle Island said multiple target zones now form part of a broader interconnected mineralized corridor rather than separate exploration targets. The zones named in the update include Tisovik, Red Rock and Kozila. It also reported visible stibnite mineralization at the Red Rock zone.
The company said this visible stibnite supports the presence of near-surface antimony-bearing sulfide systems. Middle Island CEO Peter Spiers described the expanding footprint as “highly encouraging.” He said the system remains open-ended and has been largely untested by modern exploration techniques.
Antimony’s criticality intersects with Serbia’s mining outlook
The update framed antimony as increasingly central to strategic minerals discussions in Europe. Middle Island said antimony has roles in defense applications, semiconductors, flame retardants, photovoltaic technologies and specialized alloys. It also noted that global production is heavily concentrated in China, raising supply-chain concerns for Europe and North America.
The company said this geopolitical backdrop is reshaping investor interest in Southeast Europe’s mining sector. It referenced Serbia and Bosnia and Herzegovina as well as the wider Western Tethyan metallogenic belt as potential future suppliers of strategic minerals closer to European industrial centers. It also described Europe’s demand for critical minerals tied to electrification, energy transition technologies and industrial security as a factor affecting Serbia’s positioning.
Permitting and ESG scrutiny remain key for any future development
Middle Island said environmental sensitivity around mining projects remains high in Serbia following political controversy over lithium extraction, land use and ecological impacts. It stated that any future development pathway at Bobija would likely face increasing scrutiny related to permitting, ESG compliance, water protection and community engagement. The company did not provide details on timelines or regulatory status for Bobija.
For now, Middle Island characterized Bobija results as early-stage exploration rather than a defined mineral resource. It said no JORC-compliant reserve has been established yet. The company added that substantial drilling, metallurgical studies, environmental assessment and infrastructure analysis would still be required before any economic development scenario could emerge.
The company also said the expanding scale of the silver-antimony-lead-zinc system is contributing to a reassessment of western Serbia’s geological potential. It linked this to efforts by Europe to secure non-Chinese supplies of strategic industrial and defense-related minerals.
