The geological potential of antimony, bauxite, fluorite, and magnesite of the Central Dinarides (Bosnia and Herzegovina): an 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 geologi cal 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 tem -plates, (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 fluor spar is rather rare. Our methodology described herein led to the selection of the following four teen deposits for further geological prospection and investment: the polymetallic antimony de posits 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 pro ducers of these commodities in Europe.


INTRODUCTION
Since 2011, one of the major concerns of the European Commission has been a sustainable supply of the critical materials to maintain and develop the European industries (European Commission, 2011). The European Commission Communication listed 27 critical raw materials in 2017 (European Commission, 2017). The ADRIA region hosts significant primary geological potential for six of these critical materials, namely antimony, barite, bauxite, borate, lithium and Mg (magnesite). With the exception of borates and lithium, these primary commodities were exploited prior to the conflicts in the region during the 1990s when the ADRIA region generated 11% of the world's magnesite, 5% of the bauxite, 5% of the antimony, and 3% of world's barite production (REICHL & SCHATZ, 2021). Due to a complex geopolitical situation, geological data from the ADRIA region are outdated, segmented, and limited, and largely not included in the pan-European mineral deposits databases: Minerals4EU and ProMine. The EU commission review of the list of critical raw materials (European Commission, 2017) has not taken into consideration the CRM potential of the ADRIA region, even though non-EU ADRIA countries, including Bosnia and Herzegovina, are following the European path of Slovenia and Croatia, and initiating access negotiations with significant funding
The geodynamic evolution of the Dinarides began with the Early Permian rifting of the Palaeozoic basement rocks (BOROJEVIĆ ŠOŠTARIĆ et al., 2009;BOROJEVIĆ ŠOŠTARIĆ et al., 2012), followed by the opening of the Tethyan ocean in the Late Triassic and the Late Jurassic-Early Cretaceous subduction and emplacement of the Dinaric ophiolites (PAMIĆ et al., 1998). Parts of the Sava-Vardar zone remained open until the Early Palaeogene (SCHMID et al., 2008).

(c) Oligocene post-collisional deposits of the Sava-Vardar zone
The polymetallic (Pb, Zn, Sb, Ag) vein and metasomatic type hydrothermal deposits of the Srebrenice field (Lisac, Vitlovac, Čumavić) are related to the Oligocene dacite, andesite, and associated volcanoclastic formations that intruded into Palaeozoic schists. The typical mineralogy of galena, sphalerite, siderite, chalcopyrite, stibnite, and pyrrhotite is accompanied by various sulfosalts containing Pb, Sb, Cu, Bi, Ag (ZARIĆ et al., 2000). Small-scale greisen-type Sn-bearing mineralization developed at the magmatic-schists contact zone.  DANGIĆ, 2015). The bauxites are brown-red, hard boehmite-haematite in composition (+anatas, brucite) with oolitic-pisolitic structure and appear in beds, lenses, and pocket fillings, sometimes over 40 m thick. The deposits vary in size from a few tens of thousands to over 10 million tons of bauxite (Braćan). Secondary kaolinitization is common, as well as the formation of diaspore.

(a) Early Palaeozoic continental rift-related deposits
i. As-polymetallic deposits with fluorite The arsenic-polymetallic (As, Sb, Hg, Ba, F) hydrothermal deposit Hrmza is located near Kreševo in the Mid-Bosnian Schist Mts. The ore-bearing rocks are Permo-Carboniferous phyllites, sandstones, and breccias. The mineralized zone is 0,5 to 3,0 m wide and consists of veins, impregnations, and nests. The main minerals are realgar and orpiment, followed by accessory fluorite, pyrite, bravoite, barite, muscovite, sphalerite, tourmaline, rutile, and antimonite. The fluorite has a dark purple color, and forms hexahedron crystals up to 1 cm in size. The tourmaline occurs regularly in veins alongside rutile and less commonly with fluorite. The quartz is mostly idiomorphically developed. The mineralogy points to a transition from a pneumatolytic to a hydrothermal phase, with fluorite precipitating late (JELIĆ, 1979

Magnesite deposits of the Central Dinaride ophiolitic zone
The Bosnian magnesite deposits and occurrences are genetically linked with serpentinized peridotite and dunite rocks of the Central Dinaric Ophiolite zone of Jurassic age (Appendix 2, Table 4). The quality and quantity of the magnesite increase from the northwestern Kozara-Pastirevo region towards the southeastern Krivaja-Konjuh region and the Zlatibor region. The Bosnian deposits are of the Kraubath-type and appear as several hundredmetre long veins, veinlets, and impregnations of various thicknesses, containing micro-crystalline magnesite with variable primary carbonates (dolomite, calcite), and quartz JURKOVIĆ et al., 2012). The vein-type ore varies between massive, banded, and brecciate and is up to 7-8 metres thick. About 25% of the reviewed magnesite deposits contain more than 40% MgO (Appendix 2, Table 4). The previous exploitation was mainly underground. Brecciated fine-grained magnesite deposits are often cemented with coarse-grained neomagnesite or silica (quartz, opal, chalcedony), and contain remnants of the host-serpentinite, magnetite, or chromite. In the upper part of the deposits, silica veins and veinlets are very abundant, crosscutting and prevailing over primary magnesite. Fe-hydroxide and Mn-oxide occur as a weak coating over the magnesite. As a rule, the orientation of the majority of the micro-crystalline Bosnian magnesite veins follows the major Alpine tectonic structure oriented in a NW-SE direction. The oldest veins are of Early Cretaceous age, coeval with the onset of lateritization in the Dinarides. Their vicinity close to the Oligocene-Miocene volcanic/plutonic rocks (Moševac, and Vlasenica-Srebrenica fields), as well as the observed tectonic setting and textural sub-types (breccia-type) lead to the conclusion that their origin lies near the surface epithermal processes related to post-collisional magmatism in the Dinarides (ILIĆ & JELIĆ, 1979).

InvestRM methodology
The development of the methodology within the InvestRM project is divided into several complementary phases (Fig. 2). Through constant feedback from project partners and from public presentations at project info days, the methodology was continuously improved, resulting in the selection of high-potential deposits for exploration or reinstating abandoned or ongoing mining activities.
1 st phase: Geological data template Geological templates gather available non-confidential geological data and tailor them to be aligned with: transferability to existing comparable international raw materials databases (EGDI-European Geological Data Infrastructure: http://www.europe-geology.eu/) Figure 2. Invest RM methodology divided into complementing phases.
-InvestRM standardization for antimony, bauxite, fluorite, and magnesite occurrence types in the Dinarides -Terminology aligned with INSPIRE -Presenting essential data for evaluation of exploration and mining potential The geological template contains information on the geological characteristics of each of the 126 deposits (basic deposit information, deposit characteristics), supplemented with information on raw materials, reserve, processing, waste/environmental characteristics, additional info and references, thus enabling data harvesting and linking to the existing international raw materials deposits databases such as EGDI (EuroGeoSurveys' European Geological Data Infrastructure; http://www.europe-geology.eu), and comparison with deposits worldwide. This is essential considering that the addressed critical raw materials in Bosnia and Herzegovina are currently only partly presented in worldwide databases. Geological datasets have been extracted from available elaborates, technical documentation, reports, scientific papers, and geological maps. Between the 1960s and the late 1980s, a mapping campaign supported by the government of the former Yugoslavia responsible for the economic growth and planning resulted in geological maps at a scale of 1:100.000 for the entire territory of the former state. Following the mapping campaign, ČIČIĆ and co-authors (1979) provided a comprehensive overview of the targeted raw materials in a book covering ferrous, non-ferrous, and industrial commodities, as well as the energy generating materials in Bosnia and Herzegovina, which was used as a starting point for geological data extraction and supplemented with recent publications on the selected deposits.
2 nd phase: Evaluation and verification of geological data. For each of the 126 deposits/occurrences, the investment potential was estimated. The selection criteria were extracted from the World Risk Report (2017), whereas setting and adjusting the specific parameters for the selection criteria was done by the In-vestRM consortia and consists of: (a) geological criteria (a level of current geological knowledge, i.e., data quality and quantity), and (b) non-geological criteria (social licensing, environmental management, project permits, skills availability). Specific parameters for the geological criteria were set up separately for individual raw materials and are described in Appendix 1. These include quality and quantity criteria summarizing reserves, exploration level, and favourable geological characteristics. Reserves are aligned with the law governing geological exploration (Official Gazette of the FBiH No. 9/10) and the rulebook on classification, categorization, and calculation of solid mineral raw material reserves and keeping records on them (Official Gazette of the FBiH No. 36/12).
Reserves encompass A, B and C₁ categories (proven and measured), whereas resources are used for C₂, D₁ and D₂ categories (indicated and inferred) in line with the Official Gazette of the FBiH No. 36/12. Used literature sources for Appendix 2 do not contain subdivided economical and non-economical reserves.

rd phase: Deposit ranking
The principal parameters influencing ranking are the geological data quality (complete and relevant datasets from the geological data template) and data quantity (reserves, available past exploration data), as well as social licensing, environmental management, and project permits. Parameters were weighed and assigned to ranks A, B or C, respectively, whereby A denoted excellent data with defined and up to date characteristics, B encompasses good-sufficient geological data, and C means no or minimal geological data with poorly estimated reserves and resources. The deposits considered to be the most potentially viable among the A rank deposits, namely those meeting all established criteria, were defined as A+ deposits with highly lucrative investment opportunities. The evaluated deposits were ranked and presented in detail in Appendix 2 (Tables 1-4). 4 th phase: Recognized 10+ perspective deposits Deposits ranked A+ were described as highly lucrative investment opportunities, while A ranked deposits also present investment opportunities but do not meet all the predefined criteria. A number of A ranked deposits could be upgraded to A+ deposits by providing additional datasets as part of the geological prospection.

Indicators to evaluate exploration and mining potential
The exploration potential was estimated based on the geological setting of the wider area around an occurrence and the available data from previous exploration campaigns regarding the level of uncertainty. The type of exploration method and targeted raw material (in polymetallic deposits) was also important in defining the exploration potential. Reserves are a further important indicator (aligned with a valid classification and categorization method -Appendix 2 (Tables 1-4).
To calculate the mining potential based on the geological data and economic information using the InvestRM tool, three indicators -world producer ranking, self-sustainability, and economic contribution -are introduced (Fig. 3).
The first indicator, 'world producer ranking', compares the theoretically mineable tons to the world production and helps to position Bosnia-Herzegovina on the global ranking list. The second indicator, 'self-sustainability', relates produced and imported tons, thus showing the ratio of materials derived from within BiH and is thus an indicator of self-sustainability. The last indicator, 'economic contribution', evaluates the contribution of the country's mines to Bosnia-Herzegovina's economy in terms of taxed profits. A very simplified dynamic calculation method is applied to determine this value, as the input factors are based on assumptions. The calculation results based on current reserve tonnages are compared to numbers gained after upgrading C 1 and C 2 resources to A or B reserves.

Exploration potential
The exploration potential of a specific mineral commodity depends on the geological potential, the number and distribution of occurrences and deposits in an area. Out of the total of 126 deposits of antimony, bauxite, fluorite, and magnesite in Bosnia and Herzegovina, 106 (or 84% of the investigated sites) are magnesite and bauxite deposits containing millions of tons of reserves and resources and showing high exploration potential (Table 1). When comparing all the reserves and resources, bauxites have the greatest exploration potential, followed by magnesite, antimony, and fluorspar (Table 1). The following results were obtained by applying the InvestRM methodology to the 126 investigated deposits: 1. Three out of five fluorspar deposits were evaluated as A+ deposits. A field reconnaissance investigating the three deposits indicated that only the Žune locality met each of the predefined criteria for the A+ rank. 2. Four of thirteen antimony deposits were evaluated as A+ deposits. The Čemernica and Podhrusanj deposits are abandoned deposits, while the Rupice and Veovača deposits are currently under development with an exploration license. 3. Six of fifty-seven magnesite deposits were evaluated as A+ deposits, including the magnesite field Kladanj with the most prospective operating deposit Miljevica and the poorly explored occurrences at Zeničica and Drinjača, all part of the Kladanj magnesite region. Furthermore, the abandoned deposit of Ošve, which is part of the Novi Šeher magnesite field, was recognized as a highly prospective deposit. The magnesite regions of Teslić, with several abandoned deposits, and Snjegotina, with nine deposits currently not operating, were also highly ranked (A+). 4. Fourteen out of fifty-one bauxite deposits were evaluated as A+ deposits. Of these, we highlight three perspective regions, namely the Krnjeuša-Bravski vrh-Crni vrh and Pritoka-Tihotina-Trovrh fields, with exploration licenses, and Vlasenica-Srebrenica, with several operational deposits.
In the areas listed above, the geological potential indicates highly lucrative investment opportunities with some additional exploration required to prove the reserves and resources estimated during previous campaigns. The magnesite and bauxite areas show a high prospectivity for exploration -with regions evaluated as A+ or A representing several deposits/regions controlled by the regional geological setting. In cases of positively evaluated magnesite, only the operational deposits were studied in detail. The areas surrounding existing deposits can hold additional reserves and resources, but this study included only operational or abandoned sites. Abandoned deposits were categorized into the group of prospective sites when exploitation (or exploration) activities were undertaken there in the past, and the deposit was later abandoned for various reasons, such as feasibility, legislation, or environmental hazards resulting from inappropriate exploitation and processing techniques. Larger areas present huge investment opportunities especially for long-term projects.
Magnesite and bauxite occurrences are generally ranked based on the amount of available data on reserves and resources and the quality of the data because these two CRM represent the primary or sole RM mined in the chosen deposits. Antimony and fluorite usually occur as secondary minerals in economically more interesting, predominantly Pb-Zn-Fe, or barite deposits. Therefore, reserves and resources are usually estimated, and the geological settings of studied areas were used as a key criterion. Prospective fluorspar and antimony occurrences were studied in the InvestRM consortium to provide the possible geological potential for further exploration and feasibility studies.

Bauxite
Bauxite deposits and occurrences are related to the Adriatic Carbonate Platform and the internal Dinaride Cretaceous karst units. Several promising bauxite-bearing areas have a high exploration potential (Table 1): (1) The Internal Dinarides Cretaceous karst deposit of the Vlasenica-Srebrenica region in eastern Bosnia hosts 12.950.000 t (MITROVIĆ, 2011) of reserves, representing 25% of the total bauxite reserves in BiH. Active exploitation is operated by the company Bauxite a.d. from Milići.
(2) Grmeč mountain in the Una-Sana region has potential reserves (resources), with the bauxite-bearing potential estimated to be about 20.000.000 t , and has no active exploitation. (3) The External Dinarides bauxite of the South Bosnia region (Posušje to Trebinje), based on the number of registered bauxite deposits and occurrences, is an area with  (1978,1988,2015); GRUBIĆ (1975) , 1979). Further industrial-scale testing is necessary to determine the techno-economic factors and classify proven reserves. (4) The magnesite field of Novi Šeher contains the Ošve deposit with 215.000 t of resources (150.000 t C 1 + 65.000 t C 2 ). Chemical analysis  has shown that the raw material is largely suitable for the production of metallurgical sinter, but not for the production of high-refractory bricks due to the elevated SiO 2 and CaO contents. Semi-industrial flotation experiments  yielded promising results, similar to those for Teslić, and should be complemented with industrial-scale testing.

Antimony
Economically interesting concentrations of antimony in BiH are spatially distributed across several areas, regions, or zones:  , 1982; 1995). Potential reserves of the C 2 category containing about 115,000 t with 1.1% of Sb were also reported. Based on the metallogenetic analysis, Kubat (KUBAT, 1982;1995) reported that the Podhrusanj region is very interesting for further exploration. The Podhrusanj deposit has only been partially explored. Mineralized limestones of 0.5 -1.5 m thickness appear in the wider area of the deposit containing 410,500 t of A + B + C 1 reserves with 3.4% Sb. Chemical analysis has shown that the ore does not contain As or Pb concentrations in heavy liquid analysis (classes -20 +2 mm), and the concentration by flow tables (classes -2 +0 mm) yielded a valuable antimony concentrate with a weight content of 13.9% and an Sb content of 43%, with a utilization degree of 81%.
(2) Oligocene post-collisional deposits of the Sava-Vardar zone a. The Srebrenica field in Eastern Bosnia (Čumavići) consists of a 1m thick and several hundred-metre long main vein containing 7% Sb, 2.8% Zn, 0.3% Pb, 0.05% Cu, 0.1% WO 3 , and 80 g/t Ag. Preliminary flotation extraction analyses have shown the possibility for concentrating Sb, Zn and Ag, while the Pb content is inadequate for economical extraction. The Čumavići deposit is only partially explored, showing D 2 reserves of 500,000 t (KUBAT, 1982;1995). About 100 ha of terrain around the village of Čumavići is considered promising due to the identified outcrops of antimony ore.
(3) Triassic advanced rift-related hydrothermal antimony deposits a. The Borovica-Vareš-Čevljanovići-Srednje ore zone (the Rupice, and Veovača deposits) consists of a complex polymetallic deposit of Ba-Zn-Pb ore with Sb and Hg. Significant geological research in combination with exploration drilling on the Rupice deposit was carried out in the second half of the 20 th century. Exploration results summarized by Kurtanović (KURTANOVIĆ, 1990) revealed reserves of 1,498,011 t with 3% Pb and 3,5% Zn. KUBAT (1982;1995) estimated reserves of Sb in the host dolostone of up to tens of thousands of tons with an average antimony content of 4,8%. The Veovača deposit, in comparison with the Rupice deposit, is characterized by a lower Sb content and a slightly higher Hg content. Ore reserves and resources of all categories are over 6.000.000 t with an average BaSO 4 content of 16,3%, Zn of 1,6%, Pb of 0,8%, Hg of 0,1%, and Sb of 0,1% (KUBAT, 1982;1995), and there is the possibility of discovering new ore resources in the northeast near the localities of Prijeljev and Orti. Although the Veovača location contains primarily Ba-Zn-Pb deposits, relatively low contents of Sb and Hg should not be neglected in the extraction of useful components from ore. Within the Borovica-Vareš-Čevljanovići-Srednje ore zone, the Rupice and Veovača deposits are classified as prospective deposits containing economic ore reserves (KUBAT, 1982;1995). Geological exploration is currently ongoing.

Fluorites
The occurrence of fluorite in BiH is small compared with the products of barite or arsenic mineralization. According to the scarce data, only five fluorite deposits were registered: Žune and Vidrenjak near Ljubija, Hrmza and Meovršje near Kreševo, and Pećine near Gornji Vakuf.
Based on the results of previous research (PALINKAŠ et al., 2016), as well as the conducted field research, the Žune deposit in the Ljubija ore area in the Republic of Srpska is the most promising. This deposit is Palaeozoic in age and hydrothermal in origin. It is represented by a single subvertical and partially depleted barite-fluorite vein that is several hundred metres long and has a maximum thickness of 10 m. The barite-fluorite vein is hosted by the Palaeozoic dolomites, near the contact with the Verfen shales and sandstones. The proportion of fluorite is usually about 20%, but it increases with depth, which presents an opportunity for further exploration. The inferred fluorite reserves in this deposit are estimated to be 1.500 t.

Mining potential
According to the World Mining Data (REICHL & SCHATZ, 2021), the contribution from Bosnia-Herzegovina to the mining of antimony, bauxite, fluorspar, and magnesite is comparatively low. Between 2015 and 2019, only bauxite (crude ore) and magnesite are listed, ranking Bosnia-Herzegovina in 18 th place out of the 28 bauxite producers and in 22 nd place of the 23 magnesite producers (REICHL & SCHATZ, 2021). Based on the geological potential identified for the four selected commodities, Bosnia-Herzegovina is capable of contributing much more. Following the methodology described in section 4.2, the three indicators for mining potential are discussed below, grouped by commodity.

Antimony
The world production of antimony was 125,478 metric tons in 2019, and at the same time, there was no production at the EU level. Looking at the two abandoned mines Čemernica and Podhursanj, a total of about 374 kt of reserves is estimated (A+B+C 1 reserves). Assuming a mining loss of 20% and a mine lifetime of 30 years, BiH could produce about 350 tons of Sb per year. This would make the country Europe's only producer of antimony and place it in 8th position in the world rankings (Fig. 4a).

Magnesite
A similar approach for magnesite shows a slightly different picture. The world production of magnesite in 2019 was 27 million metric tons, with about 11% being mined in Europe (EC) and Bosnia-Herzegovina contributing with 1400 tons. Looking at the deposits that have been identified as highly graded investment opportunities and only focusing on the abandoned and closed mines, Bosnia-Herzegovina is capable of producing an additional 36 kt of magnesite 1 . This would improve the country's position from 22 nd to 16 th in the rankings (Fig. 4b).
Similar thoughts would be applicable for the bauxite and fluorite deposits and occurrences, but these are not emphasized here as Bosnia-Herzegovina already mines more than 1 million metric tons of bauxite per year, and fluorite occurrences will not play a major role based on the currently available data.

Indicator 2: Self-sustainability
A vital topic is the importing of necessary commodities. Currently, Bosnia-Herzegovina does not import any antimony ores and concentrates but imports about 2 to 3 tons of antimony oxides per year. Assuming a working processing technique, the stibnite deposits could provide around 2 tons of antimony per year. Depending on the field of application, Bosnia-Herzegovina may reduce the required imports and could even start exporting antimony ores. The European Union imports roughly 4 kt of antimony ores and would benefit from a local provider (World Trade Organization, 2021).
Imports of magnesite vary, whereby it was 105 tons of sintered magnesite in 2019 (World Trade Organization, 2021). With the additional tonnage from the mines currently not operating, the magnesite mined in Bosnia-Herzegovina could reach selfsustainability and BiH could become an exporter.
Numbers on bauxite imports as crude ore are difficult to identify. Aluminum ore and concentrate imports amounted to 210 1 Taking the available resources upgraded to reserves (amount reduced by 25%) and assuming again a lifetime of 30 years for the underground mine operation, the deposits at Blatnica, Bukovični jarak and Milošev jarak from the Teslić and Jelovac fields and Pločni (from the Snjegotina -Banja Luka field) could provide 29 kt. With the open pit mine in Ošve reopened, there is a total amount of 36 kt. kt in 2019, whereas exports were in the range of 32 kt (World Trade Organization 2021). Both values have increased in recent years. It seems unlikely that additional bauxite deposits can dramatically change the import to export ratio but might be able to help maintain the balance.
Fluorspar imports into Bosnia-Herzegovina were in the range of 1.4 kt in 2019. The assigned value for this import is about 550.000 USD. Utilizing the country's own fluorite reserves would help to reduce these imports.

Indicator 3: Economic Contribution
This potential can also be expressed in monetary units. While the exact prices that could be obtained by selling the products cannot be forecast without proper feasibility studies, including market studies, the potential may be highlighted by simply assuming a perfect market and ideal conditions. Prices for antimony and raw magnesite are currently listed at 6586 USD/t and 89 USD/t, respectively (Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) 2021). All deposits examined here are underground mines, except the one in Ošve. To estimate the operating costs and capital costs for the mines, figures from an Estimator's Guide (Info-Mine USA, Inc. 2016) are extrapolated to account for the estimated production tonnage and updated to current values by assuming an inflation factor of 8.5%. For all subsurface mines, a mechanized cut and fill operation with adit access is assumed. This seems feasible, as all deposits in question are irregular veins or of vein-type. The open pit mine is assumed to have a waste to ore stripping ratio of 8:1. When combining these estimates with the production tonnages from the previous paragraph, the theoretically achievable prices and the estimated costs and, thus, a potential net profit value can be calculated ( Table 2). The calculation is based on currently stated reserves and compared to a theoretical tonnage after additional exploration. The reserves and resources upgraded to reserves are taken from the InvestRM reports are adjusted to account for mining losses. Costs are based on figures from InfoMine but adjusted to the production rates for an estimated lifetime of 30 years per deposit. Together with prices for antimony and magnesite, a simple NPV calculation is performed. Further assumptions: 12% discount rate and a LOM of 30 years, no price or cost increases over the years; re-occurring capital costs every 10 years (50%, 25%, 25%).
For Čemernica, a positive value can be achieved if additional metals (Zn and Ag) are mined and sold. The focus should be on processing to ensure the inclusion of Zn and Ag in the product portfolio. Looking at the overall economy of Bosnia and Herzegovina, mines could contribute ten percent of the profit as corporate income tax.
In Podhrusanj, the loss can be halved if additional exploration can prove 410 kt. Further engineering to reduce the capital costs and a market study on price development may produce a positive NPV.
The open pit mine in Ošve can achieve a significant improvement (factor 10) in the mineability if reserves can be upgraded from the C 1 and C 2 to the A and B categories. Additional improvements in mine design can reduce operating and capital costs.
For the Telić and Banja Luka fields, the calculation shows that currently calculated losses can be halved if the deposits per field could be combined. Using these synergies together with a reserve re-classification and a proper mine design, the operations may become very profitable. Additionally, attention should be paid to the inclusion of a refinement step to improve the final product and increase the achievable prices.
As described, antimony deposits also host Zn, Ag or, in the case of Rupice, BaSO 4 . A closer analysis of the processability of the extracted ore could enhance the product portfolio of the mining sites in Rupice, Čemernica, and Srebenica and thus boost their profitability.
Fluorspar deposits currently do not provide enough data for a similar calculation, and most bauxite mines highlighted in the FIPA brochure are already operational. Therefore, both commodities are not included in this subsection.
All costs and price figures in this chapter are based on profound assumptions but would require further market studies (true prices, real demand) and costs (re-opening the abandoned mines, processing, employees, and energy). Furthermore, more detailed mine plans are necessary to estimate mining losses and production figures. In some cases, e.g. Podhrusanj, additional exploration could improve the inferred reserves (see section 5.1 for comparison) but will generate some costs. For all mines, feasibility studies would deliver more realistic estimations about the profitability and might provide better profit values.
For all deposits described here, two different courses of action can be taken: starting exploitation or continuing extraction by renewing existing mining permits. Either way, a more profound financial calculation on a micro-economic level is necessary, as the most critical parameter for the exploitation is the financial feasibility of a mining project. A major decision driver for a company to start or continue mining of a particular deposit is the ability of the mine to create a profit. It is no easy task to answer the question about the true mineability of a mine or deposit. The general process of evaluating mine investment opportunities usually includes the assessment of four main, interrelated factors: the ore reserves, the cut-off grade (or quality), the mine size, and the production costs (GENTRY & O'NEIL, 1984).
For mining financial calculations, investors require a sound and reliable data base. This data needs to cover all the main factors of production, including the deposit and relevant geological data. Especially for foreign investors, it can be a very time consuming and exhausting task to find consistent data on economic and social figures or deal with information about concessions or local political strategies. The InvestRM decision making tool offers a quick, user-friendly, and easy way to access and gather all the necessary information in a comprehensive report (HAINDL, 2020).

CONCLUSION
A total of 126 deposits and occurrences of antimony, bauxite, fluorspar, and magnesite occurrences in Bosnia and Herzegovina have been validated using the developed InvestRM methodology to determine their exploration and exploitation potential. The developed InvestRM methodology consists of the following steps: (1) preparation of the geological data templates in line with international raw materials datasets (M4EU, EGDI) for 126 deposits/occurrences; (2) evaluation and verification of the geological data in order to estimate the investment potential using criteria extracted from the World Risk Report (2017) and specific InvestRM parameters; (3) ranking deposits according to the quality of the geological data (complete and relevant datasets from a geological data template) and data quantity (reserves, available past exploration data), as well as social licensing, environmental management, and project permitting, into ranks A, B or C, and (4) identification of the 10+ perspective deposits (barite-fluorite vein-type deposit Žune; 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; Appendix 3, Table 1-4) meeting all predefined criteria and parameters.
Analysis shows that a significant potential in primary critical raw materials such as bauxite (56 Mt Three indicators: the world producer ranking, self-sustainability, and economic contribution, are included in the analysis of the country's mining potential. Bosnia-Herzegovina could play a major role in Europe's strategy to become self-sustaining in the supply of critical raw materials. The brief economic discussion shows that there is a need for investments in geological prospection and engineering to transform the abandoned mines into operational sites and prepare feasibility studies. Antimony and fluorspar occurrences are part of the polymetallic deposits and can add value to low-feasibilty deposits. Large magnesite and bauxite regions provide opportunities for additional exploration and improvements in the exploitation process. Considering all the facts, investments in exploration and mining could boost BiH's economy and create value not only for the country itself, as it could be self-sustaining in antimony and magnesite, but also as a supplier for Europe.