The Žune Ba-F epithermal deposit: Geophysical characterization and exploration perspective

The Žune barite-fluorite ore body in northwestern Bosnia and Herzegovina has been explored using geophysical methods to determine the spatial distribution of the mineralization. The mineralization occurs in a 50 m long ESE-WNW fault zone in the form of a subvertical barite-fluorite vein, transforming to strings of tiny barite veins and impregnations at the immediate contact with the host dolostone. The geophysical research included 2D electrical resistivity tomography (ERT) measured along four profiles. In addition to resistivity inversion results, forward modelling has been performed along two profiles transecting the mining cut. Prior to surface geophysical measurements, detailed geological field mapping of the ore body and host rocks was undertaken. The main faults defined by geological field mapping, have been confirmed with geophysical results as well as the contact of the host dolostone with Lower to Middle Triassic sandstones. The contact is defined to the south of the deposit. However, based on the resistivity model, the position of the contact is about ten metres further south. The forward modelling results revealed that the barite-fluorite vein in the area of the mining cut is limited to a depth of about 10 m and the length is about 70 m. The vein is up to 5 m thick and almost 10 m wide. There is no indication for barite-fluorite mineralization in the area south of the studied mining cut with predominant Triassic sandstones, while anomalies that may be associated with ore bodies are present in the northern and northeastern parts, composed of Carboniferous dolostone

Žune Ba-F epithermal deposit Part 1: Mineralogical and geochemical characteristics

The Žune Ba-F epithermal deposit is situated in the Ljubija ore field (NW Bosnia and Herzegovina), within Upper Palaeozoic dolostone. A typical ESE-WNW Variscan vergency fault zone separates the dolostone from Lower Triassic schists and sandstones. External and internal pseudo-bedding, with massive, homogenous structure and partial limonitization characterizes the dolostone. Its geochemical composition exhibits low SiO2 (1.33 – 2.06 mass. %), Al2O3 (0.27 –0.38 mass. %), BaO (0.02 – 0.83 mass. %), ƩREE (5.7 – 9.4 ppm), Sr (61.7 – 120.4 ppm), Sm (0.3 – 2.2 ppm) and Eu (0.1 – 0.6 ppm), while having high CaO (30.24 – 32.38 mass. %), MgO (16.47 – 17.35 mass. %) and LOI (44.6 – 45.58 mass. %). The dolostone-mineralization contact zone consists of metasomatically recrystallised host dolostone with quartz and pyrite, where the presence of accessory tremolite, magnesiochloritoid and pyknite indicates peak formation conditions in the pre-mineralization phase with temperatures above 300°C. Two ore types are described: (i) Ba-F vein-type mineralization composed of barite – fluorite ± quartz, and (ii) hydrothermal breccia composed of coarse-grained fluorite and barite, surrounding fragments of dolostone, and occupying ≈20 % of the deposit. Mineralized samples show slightly elevated SiO2 (2.20 – 5.53 mass. %) and Al2O3 (0.24 – 0.74 mass. %), low MgO (below 0.02 mass. %) and LOI (0.3 – 3.1 %), with high BaO (up to 50.74 mass. %), CaO (up to 66.03 mass. %), ƩREE (20 – 166 ppm), Sr (exceeding 1 mass. %), Sm (up to 118 ppm) and Eu (up to 44 ppm). Elevated Sr can be correlated to other barite epigenetic hydrothermal deposits in the Dinarides, interpreted as BaSr substitution in the barite crystal lattice. Fluorite-rich samples are characterized by Y (0.6 –49.2 ppm) and HREE enrichment, accompanied by depletion of LREE. The Ba-F deposit Žune, having variable REE concentration and a negative cerium and ytterbium anomaly corresponds geochemically to world-class fluorite deposits associated with carbonate sedimentary rocks

Geological potential of antimony, bauxite, fluorite, and magnesite of the Central Dinarides (Bosnia and Herzegovina): exploration and exploitation perspective

This paper presents the critical raw materials (CRM) potential of antimony, bauxite, fluorite, and magnesite deposits in Bosnia and Herzegovina, discusses their metallogeny and joint geological features, and explains the methodology of the InvestRM application and evaluation criteria for the selected commodities in the following steps: (1) preparation of the geological data templates, (2) evaluation and verification of the geological data, (3) ranking of deposits according to the geological data relating to quality and quantity, and (4) identification of the 10+ perspective deposits. Existing geological datasets show the existence of significant potential in primary CRM such as bauxite (56 Mt), magnesite (4 Mt), and antimony (0.2 Mt) in Bosnia and Herzegovina (BiH). The geological settings of BiH provide favourable metallogenetic conditions primarily for bauxite and magnesite deposits but also for antimony within polymetallic deposits, while fluorspar is rather rare. Our methodology described herein led to the selection of the following fourteen deposits for further geological prospection and investment: the polymetallic antimony deposits Čemernica and Podhrusanj, antimony fields Srebrenica and Rupice; magnesite fields Kladanj, Banja Luka, Teslić and Novi Šeher and bauxite regions Vlasenica-Srebrenica, Grmeč Mountain deposits in Una-Sana region and South Bosnia regions from Posušje to Trebinje. A basic economic calculation based on the world producer ranking and a self-sustainability and economic contribution assessment shows that further investments in geological exploration and mining of antimony, magnesite, and bauxite CRM could place BiH on the list of important producers of these commodities in Europe

The future of mining in the Adria region: current status, SWOT and Gap analysis of the mineral sector

The Adria region which includes the countries of: Albania, Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, and Serbia, and corresponds to the Dinarides, northwesternmost Hellenides, and the Vardar zone, has a long history of mining. Here, the main strengths and challenges of the mineral sector of the Adria region were assessed using the following methodology: (1) presentation of the current status of mineral exploration and exploitation, (2) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis on parameters including geological potential, economic environment, legal and regulatory framework, innovation and technology framework, environmental protection and land use planning, governmental and social potential, human resources and educational potential, (3) Gap analysis, and (4) integration of the results obtained in the development of a roadmap for the actions required to promote investments in the mineral sector in the Adria region. The main strengths of the regional mineral sector include the significant mineral potential due to a favourable geological setting, significant reserves, a long mining tradition, and active exploration areas, as well as a significant number of active and abundant mines and the availability of secondary raw materials. Nevertheless, there are many challenges that the mineral sector faces, such as difficulties in ensuring social acceptance, a lack of new exploration campaigns in many areas, estimation of resources or reserves that do not follow international codes and standards, regulations related to environmental issues in the mineral sector of Adria countries that do not comply with European legislation, and the limited availability of qualified technical, scientific and managerial personnel involved in the whole mineral cycle. Therefore, actions and measures such as awareness campaigns to highlight the significance of Raw Materials in the sustainable development of the region, further exploration, reserves calculation in alignment with internationally recognized codes, harmonization with spatial plans, and reforms to attract investors and capacity building programs should be taken for further development of the Adria region’s mineral sector in a sustainable manner

The contribution of geochemical and mineralogical characterization of iron slags in provenance studies in the Podravina region, NE Croatia

Archaeological excavations in the Podravina region led to discovery of sites with traces of bloomery iron production during Late Antiquity and the Early Middle Ages. Mineralogical analysis of the slags recognized fayalite as the main mineral phase, while geochemical analysis confirmed high Fe contents, typical for bloomery iron smelting. Based on the previously established occurrences of bog iron ores in the study area, provenance studies were carried out using trace and rare earth elements to create a geochemical signature. Similar shapes and patterns of bog iron ores and iron slag signatures imply a genetic connection between the ore and the slag, as well as variation related to the temporal and spatial context of both slags and ores

FORMATION MECHANISMS OF FE-MN CONCRETIONS IN THE VIJENAC QUARRY, DINARIC OPHIOLITE ZONE

Rudnik Vijenac, smješten u blizini Tuzle, Federacija Bosne i Hercegovine, sastoji se od karbonatnih stijena, koje su lokalno proslojene tektonski poremećenim naslagama siltita i pješčenjaka s Fe-Mn konkrecijama. Sam kamenolom nalazi se u zoni dinaridskoga navlačnog pojasa (Pogari serija naslaga) koje diskontinuirano leže na ofiolitnome melanžu i ofiolitnim navlačnim naslagama. Petrografske, kemijske i XRD analize pokazale su da se konkrecije mogu podijeliti u dva tipa: (i) Mn-obogaćene konkrecije s ≈ 17 wt.% udjela Mn s kompaktnom strukturom te (ii) Mn-osiromašene s ≈ 8 wt.% udjela Mn te poroznijom strukturom. Udjeli Ca, Mg, Fe i organske tvari obaju tipova konkrecija podjednaki su. Udio Ni pozitivno korelira s Mn, udio Cr pozitivno korelira s Fe. Prema petrografskim i XRD analizama konkrecije se sastoje od kalcita, dolomita, hematita, todorokita i takanelita. Todorokit je karakterističan mineral za konkrecije formirane dijagenetskim rastom. Petrografska istraživanja potvrdila su rast konkrecija u trima fazama s ukupno dvjema generacijama kalcita. Promatrane konkrecije nalaze se unutar konsolidiranih pješčenjaka te nasljeđuju njihove sedimentne strukture – stoga se pretpostavlja kasnodijagenetski proces rasta.Vijenac quarry, near Tuzla in Bosnia-Herzegovina, is composed of carbonate rocks locally embedding tectonically disturbed siltite and sandstone with Mn-Fe concretions. The quarry itself represent a part of Dinaric overstep sequences (Pogari series) unconformably overlying ophiolite mélange and ophiolite trust-scheets. Petrographic, chemical and XRD analyses had shown that the concretions may be divided into two types: (i) Mn-rich concretions with ≈17% of Mn and compact texture and (ii) Mn-poor (≈8% of Mn) and porous texture. The amount of Ca, Mg, Fe and organic matter, as well as analysed microelements (Ni, Cr) in both concretion types are similar. According to petrographic and XRD analyses, concretions are composed of calcite, dolomite, hematite, todorkite and takenelite. Todorokite is characteristic for concretions formed by diagenetic growth. Petrographic study confirmed the development of concretions within three stages including two generations of calcite. The studied concretions are formed within consolidated sandstones inheriting their sedimentary textures - therefore a late diagenetic process is assumed

Divergent drift of Adriatic-Dinaridic and Moesian carbonate platforms during the rifting phase witnessed by triassic MVT Pb-Zn and SEDEX deposits; a metallogenic approach

Early-intracontinental rifting of Pangea is result of thermal doming in Uppermost Permian time giving rise to the formation of horst-graben  structures, followed by slow subsidence, marine transgression and evaporate deposition. Consequence of incipient magmatism are numerous geothermal fields and subterrestrial hydrothermal siderite-barite-polysulfide deposits (PALINKAŠ et al, this issue). Advanced rifting magmatism as a successive stage in Middle Triassic brought intensive submarine volcanism, accompanied by coeval sedimentation of chert and siliciclastics, building up volcanogenic-sedimentary formations. Volcanic activity with explosive phases and generation of large volumes of pyroclastic rocks in the rifts produced concomitant mineralization with numerous SEDEX deposits of Fe-Mn-Ba-polysulfides. Passive continental margins flanked by the Adria-Dinaridic carbonate platform as passive continental margin of the northern Gondwanaland and Moesian carbonate platform, as a counterpart on the European passive continental margin, were divergently drifted in the coarse of the advanced rifting. A fast growing carbonate platforms, developing gradually, covered  evidences of the earlier intracontinental rifting and their ore formations. On the other hand, the carbonate platforms themselves host specific Pb-Zn deposit, well known as Mississippi valley type, (MVT) or Bleiberg-Mežica type according the traditional european terminology. Triassic MVT and SEDEX deposits are symmetrically situated on the both sides of the divergent passive margins in this early history of the Tethyan ocean.</p

Virtulab – Integrirani laboratorij za primarne i sekundarne sirovine

Cilj projekta Virtulab je poboljšati znanstveno-istraživačke i nastavne kapacitete pet sastavnica Sveučilišta u Zagrebu u sektoru primarnih i sekundarnih sirovina te dosegnuti europske i svjetske standarde praktične primjene znanja u gospodarstvu. Virtulab okuplja istraživačke kapacitete koji zadovoljavaju potrebe prospekcijskih istraživanja primarnih i sekundarnih sirovina, eksploatacije, oplemenjivanja, proizvodnih procesa, recikliranja i pronalaženja zamjenskih sirovina. Projekt doprinosi: 1) jačanju kvalitete znanstvenih istraživanja uvođenjem suvremene te povećanjem dostupnosti postojeće instrumentacije, 2) povećanju produktivnosti odnosno broja znanstveno-istraživačkih radova i broja prijava kompetitivnih znanstvenih i inovativnih projekata, 3) poboljšanju kvalitete nastave uz jačanje kompetencija studenata i time njihove konkurentnosti i zapošljivosti na tržištu rada i 4) transferu znanja i inovacija prema gospodarstvu. Implementacija projekta dugoročno će poboljšati dostupnost i iskorištenost primarnih i sekundarnih sirovina, pozitivno utjecati na okoliš i gospodarstvo i smanjniti uvoznu ovisnost Republike Hrvatske i Europske Unije u sektoru ne-energetskih mineralnih sirovina