Factors and indicators of the geological and economic assessment of the coal resources in the Republic of Srpska as the starting basis for a deposit evaluation as a function of the national and commercial profitability

The geological-economic evaluation of coal deposits in the Republic of Srpska includes two ways of evaluation the deposits: evaluation of coal deposits without taking the time factor into account (analysis the parameters of the static evaluation methods: economy and profit rate) and evaluation the three largest coal deposits (Gacko, Ugljevik and Stanari) with taking the time factor into account, evaluation the economic profitability (commercial and national). The following dynamic methods are used to assess the commercial profitability: Net present value, internal rate of return and cash flow discounting method for determining the return period of investments. The analysis of the economic effects of the investment project (assessment of deposit) is performed using a "cost-benefit" analysis. This analysis was performed using the following methods: NPV, IRR and DCFROI. As a part of the economic analysis, the analysis of the conditions of uncertainty is processed, i.e., sensitivity analysis of coal deposits, namely: static sensitivity analysis (determining the breaking point of profitability and critical price of a unit of mineral raw material) and dynamic sensitivity analysis, directed at the results of changes in parameters (income, costs, investments and legal obligations) to the changes in the calculated internal rate of return [2]. For the assessment of national profitability, the basic criterion of national profitability, net added value - NVA, is applied. In addition to the direct effects of coal production in the Republic of Srpska, on the national economy (financial income and expenses), the additional criteria were also analyzed: effects on employment, foreign currency inflow and international competitiveness, i.e., applying a "cost-benefit" analysis, an analysis of indirect effects is also performed (effects) of coal production on the national economy of the Republic of Srpska

Potentiality of the raw material coal base from the Gacko deposit in a function of providing the energy fuel for strategic planning of the TPP Gacko 2

Coal resources, in addition to oil, gas and uranium as a non-renewable and hydropotential as a renewable energy source, represent the most significant part of energy potential and an energy source of strategic importance on the Republic of Srpska. The modern pace of technological and industrial development causes a permanent increase in coal exploitation and consumption. The use of this resource must be planned and extremely rational. Coal deposits in the Republc Srpska are differed in the structure and quantities of reserves, geological and technical-economic conditions of exploitation and quality. Geological reserves of the Gacko coal deposit amount to 330 Mt. According to the current geological documentation, the balance reserves are ≈182 Mt, with an energy potential of 545 TWh. According to the processed performance indicators, the balance and mineable reserves of coal enable a long-term supply of fuel for the current and future thermal power plant under the favorable economic conditions. In order to provide the required amount of energy for operation the existing and "new" thermal power plant in Gacko, it is necessary to carry out the geological explorations in order to reproduce the mineral and raw material base. The duty of every company engaged in exploitation the coal energy resources is a continuous performance of geological explorations in order to find the new ones or transfer the existing reserves into a higher category. The future development and level of coal production from the Gacko deposit will mostly depend on the electricity production in the Gacko Thermal Power Plant. It would certainly strive for fulfillment the basic conditions, i.e. the cost of coal heat utilization, as in many other countries, be at least approximately competitive with the cost of heat from the other primary energy sources (hydro sources, imported energy, etc.).In order that the Gacko non-renewable energy resource would survive and evolve in a particular environment, it must have a clearly defined purpose of existence. This purpose of existence is primarily reduced to a multiphase process of providing and using a non-renewable energy resource in accordance with the realistic natural, economic and ecological opportunities, in relation to which there are the expressed needs in a wider or narrower environment

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

Formation analysis of Maglajci-Moštanica ophiolytic zones in the North of Kozara for the use of rocks in construction

Based on the field work and laboratory research, the basic geological characteristics of the ophiolitic melange of northern Kozara are presented, with an emphasis on the Maglajci ophiolitic block. Criteria for separations of formations were established and then applied in the analysis, especially those geologically directly recognizable in the field and outcrops, so one ore formation with two ore subformations was separated in the Maglajci block. In the central zone of block, the basalt outflows and diabase are dominant, while in the south of the block it is an outflow basaltic sequence of the ocean floor with the acidic differences of rhyolites and keratophyres. The second subformation also includes the Moštanica and Vojkova Bloc as a whole. The ore bearing formation is evaluated as a medium to low perspective formation, while parts of the Maglajci block with a massive to brecciated outflow are highly perspective terrain. There are rocks of good physical-mechanical characteristics and they meet the most requesting standards for road building. The results of formation analysis have denied a prior prognosis of ore bearing characteristics of this area, because it was thought that the ophiolitic blocks was built almost exclusively of diabase, and that the fields with those blocks are equally and good perspective for researching the deposits of construction stone

Metallogeny of the Ljubija ore region

The Ljubija ore region is a part of the Triassic, regional, internal metallogenetic zone of the Middle Dinarides. It is located approximately in the middle of this larger metallogenetic unit and has many characteristics in common with its other parts. After many wanderings in the interpretation of the genesis of iron ore in Ljubija, it was definitely determined that the metallogeny of iron is of the Triassic age, then, that it is associated with the deep rift dislocations, which allowed the circulation of hydrothermal solutions originating from the Upper mantle, that the primary economic concentrations of iron are found only in the Olistostromic member of the Javorik flysch formation and the secondary ones, redeposited in the Neogene-Quaternary lake sediments of the Prijedor-Omarska basin. Based on the distribution of mineralization in the Ljubija ore region, two ore subregions, one polymetallic ore zone and a group of ore fields with barite, were identified. All the above knowledge, along with the analysis of control factors of mineralization and the main prospective indications, enabled the division of entire region into areas with various categories of perspectives according to the justification of further research. Based on the results of many years of research, this work presents the results of metallogenetic analysis of the Ljubija ore region. All results of the future research should continuously supplement, correct and improve the metallogenetic and prognostic map and our metallogenetic knowledge about the region

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 in order to determine spatial distribution of the ore body. At the Žune site, barite mineralization occurs in the form of veins and is hosted by dolostone. A geophysical survey was carried out with the aim to detect anomalies associated with the barite-fluorite deposit and to characterize the abandoned old deposit. Therefore, 2D electrical resistivity tomography (ERT) was measured along four profiles. Prior to surface geophysical measurements, detailed geological field mapping of the ore body and host rocks was undertaken. The geometry of the abandoned mining cut with steep walls and complex structural setting with barite that incorporates coarse fragments of host rock and fluorite makes interpretation of the results challenging. The collected geological data were used to calibrate the geophysical models. Forward modelling in addition to inversion of the ERT data helped to reduce the ambiguity of geophysical data interpretation. The results revealed that the barite vein in the area of mining cut is limited to a depth of about 10 m and length is about 40 m. There is no indication for barite mineralization in the area south of the mining cut, while anomalies that may be associated with ore bodies are present in the northern and northeastern part

IMPORTANCE OF OLISTOSTROME MEMBER FOR METALLOGENY OF LJUBIJA IRON ORE DEPOSITS

Ljubija mining area is built of more formations that belong to the Carboniferous, Permian, Triassic andCenozoic. From all of these, only two are metalliferous to iron: Javorik formation with olistostromemember and Neogene-Quaternary of Prijedor basin. The first includes primary siderite and ankeritepartially limonitised ore and in the second only redeposited limonite (limonite pieces and dust, knownunder the commercial name "brand"). Appearance of iron is also in other members of Javorik formationand other formations, but these are just thin veins. They have no significance for the economicexploitation but are an important element in the interpretation of metallogeny in the region. Thesefindings came from many years of fieldwork and synthesis of all published and unpublished data relatedto iron ore in this area.Therefore, this work gives special importance to olistostrome member, its stratigraphic position andmetallogenic characteristics

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 AND ECONOMIC ASSESMENT OF THE PERSPECTIVE OF THE MINING IN LJUBIJA ORE REGION

The iron ore of the Ljubija ore region for decades has a very great impact on the overall socialreproduction in the area of the city of Prijedor, RS, BiH, which is clearly connected with theconstant renewal and intensification of the production process. We have systematic geologicalexplorations last over 135 years and exploitation with certain interruptions over 100 years.Existing resources/reserves should be optimally activated in order to achieve the commercial viability ofinvestment funds invested in them, but also those that have yet to be invested, and a certain expectednational benefit, and at the same time an intensive geological exploration of the potential space forfinding new reserves in terms of iron ore base.The paper attempts to assess the real justification of further geological exploration and exploitation inthis area and the strategy for further development of iron ore mining