Podzemni radovi

TECHNICAL ANALYSIS OF THE POSSIBILITY OF EXPANDING THE QUARRY WITH DEEP BENCHES AT THE TREBAČKO BRDO

2026-07-01T12:21:13+00:00

This paper presents a comprehensive technical analysis of the potential expansion of the Trebačko Brdo quarry through the introduction of deep benches, with the aim of increasing extraction capacity while maintaining slope stability and ensuring compliance with environmental regulations. The geological, geomorphological, and engineering-geological characteristics of the site indicate favourable conditions for the continued exploitation of limestone. Laboratory testing confirms the high quality of the mineral resource, particularly in terms of its chemical composition (CaO > 50%) and physico-mechanical properties (compressive strength > 100 MPa).

The proposed expansion concept предусматри the successive development of benches down to an elevation of 470 m above sea level, increasing the total extraction height to 85 m. Slope stability has been verified through a calculated safety factor (F = 3.48), while the optimal working bench width (27.5 m) allows for the integration of spiral ramps, safety zones, and drainage systems. Special emphasis is placed on geotechnical challenges, including rock mass discontinuities, interaction with groundwater, and the need for adaptive planning.

The analysis also includes an assessment of environmental impacts, with particular focus on dust emissions, hydrogeological changes, and the necessity of technical reclamation. In conclusion, the proposed pit expansion model demonstrates high technical feasibility, safety, and compliance with contemporary mining practices, thereby enabling the sustainable exploitation of technical stone at the Trebačko Brdo site.

UPGRADE OF A CONVENTIONAL PUMPING UNIT WITH A COMPRESSOR FOR PRESSURE REDUCTION IN THE CASING, AIMED AT INCREASING OIL AND GAS PRODUCTION AND REDUCING CO2 EMISSIONS

2026-07-01T12:20:16+00:00

In the paper, the authors are conducing research into designing and upgrading the conventional system of oil production using a compressor for pressure reduction in the casing, aimed at increasing oil and gas production and reducing CO₂emissions. As oil exploitation progresses, the natural pressure of a reservoir decreases, which results in reduced production from the wells. Therefore, compressor design becomes essential for production optimisation. The paper analyses the methodology of designing a compressor which is integrated into the existing sucker rod pump systems, bearing in mind specific pumping unit dimensions, the annular pressure and the quantity of produced gas. The proposed approach includes precise flow dynamics measurement and analysis, as well as optimisation of the geometry of compressor installation in order to achieve maximum efficiency. Pilot projects at nine wells have shown a significant increase in fluid production and decrease in CO₂emissions by using a closed casing and directing gas into the production line. The research provides an insight into possible benefits of integrating a compressor with production systems, thus ensuring a more sustainable approach to oil and gas exploitation.

SPECIFICITIES OF GEOLOGICAL SAMPLING METHODS IN ALLUVIAL DEPOSITS

2026-07-01T12:09:24+00:00

Sampling alluvial deposits is important in geological research, providing data for understanding sediment composition, stratigraphy, and resource potential. The study including testing alluvial wells, conducting examinations during shallow shaft mining operations, and assessing deposits through floating dredgers. Across all methods, the key requirement is proper sampling and ensuring a sufficient quantity of material. Analyses of the collected samples, supported by calculations, reveal both the concentration of valuable minerals within the deposit and the spatial consistency of their distribution. In drilling testing methods, it is essential to precisely measure the volume of the drilled rock column and to determine the concentration of the useful component in the material recovered through washing. During mining operations, the sample comprises all material removed while deepening the shaft by 0.5 or 1.0 m. Testing of floating dredger fields is conducted during exploitation measurements as the dredger advances along the transverse profile from one end of the deposit to the other. The horizontal spacing between sampling points is typically 5 m. Samples are taken first at the greatest digging depth and then at every meter of sediment. Due to their mobility and precision, floating excavators are particularly suited for operations in remote or inaccessible regions.

IMPROVEMENT OF BUSINESS OPERATIONS THROUGH PHASES OF TECHNOLOGY DEVELOPMENT FOR MONITORING WELL PARAMETERS

2026-07-01T12:22:19+00:00

The subject of the paper is a comparative analysis of technologies for monitoring well parameters through three phases of development. The research is based on a case study conducted on an oil field with 152 wells in Serbia. The aim of the study is to determine the impact of digitalization and wireless data transmission on operational efficiency and reduction of production costs. The methodology includes analysis of operational data collected during years of field work, including parameters such as number of operators, response time, and logistics requirements. Results show that the transition from manual data recording to real-time systems reduces the number of required operators by 83 percent. Response time to changes in well operation was reduced from 48 hours to 30 seconds. Analysis of logistics parameters indicates a reduction in daily vehicle mileage from 230 to 14 kilometers, accompanied by a 94 percent decrease in CO2 emissions. The paper also identifies limitations regarding data resolution and the influence of human factors on the speed of implementation of new solutions. The findings confirm the economic and environmental justification of introducing modern measurement systems in the oil industry. Identified intermediate phases point to the need for gradual adaptation of work processes to new technologies. The obtained data serve as a basis for future research in predictive maintenance and application of artificial intelligence algorithms in oil exploitation.

DEVELOPMENT OF LiGe₂(PO₄)₃ CRYSTALLINE PHASE IN GLASS SUBJECTED TO NON ISOTHERMAL TREATMENT

2026-07-01T12:23:06+00:00

The nucleation behavior of germanium phosphate glass under non‑isothermal conditions was examined using differential thermal analysis (DTA). The study focused on how both the duration and temperature of pre‑DTA heat treatment affect the characteristic DTA peak temperature (Tp). A complex relationship between these parameters was observed. At constant temperatures, extending the annealing time during the pre‑DTA treatment led to a reduction in the Tp value. Furthermore, the effect of pre‑DTA treatment temperature on DTA parameters revealed that, for annealing times longer than tind, the inverse dependence of Tp on T mirrored the influence of temperature on nucleation rate (I), particularly in cases where the nucleation and crystallization regions partially overlapped. Differential thermal analysis (DTA), which we used in the manuscript, is one of the most reliable methods for monitoring phase transformations in glass systems. This method enables accurate detection of energy changes during heating. The application of this technique in non-isothermal conditions provides key data on the thermal stability of the samples and the kinetic parameters governing the crystallization process. Special importance is attached to the study of nucleation, which, as the initial phase of crystal growth, directly determines the final morphology and properties of the resulting glass-ceramic.

CORRELATION BETWEEN UNIAXIAL COMPRESSIVE STRENGTH AND WATER CONTENT OF BEOČIN MARLS

2026-07-01T12:23:48+00:00

The uniaxial compressive strength (UCS) is one of the most important strength parameters for evaluating the mechanical behavior of rocks and is widely used as a fundamental input in rock mass characterization systems, empirical classifications, strength criteria, and various engineering design and calculation methods. Weak rocks, such as marls, exhibit a pronounced sensitivity to water content, which can significantly influence their strength and deformation characteristics. This paper investigates the correlation between water content and the reduction in UCS of marl samples. A series of laboratory tests were conducted on specimens with varying water contents. The results show a clear inverse relationship between water content and UCS, with strength decreasing progressively as water content increases. This reduction is attributed to the weakening of interparticle bonds, softening of the clay matrix, and increased pore water effects within the rock structure. The experimental data were analyzed to establish empirical relationships between water content and UCS reduction, providing a basis for predicting strength degradation under different environmental conditions. The findings highlight the critical role of water content in controlling the mechanical behavior of marls and emphasize the need to account for water content in geotechnical design and stability assessments in marl formations.

OIL AND NATURAL GAS PRICE DYNAMICS IN THE 21st CENTURY: A REVIEW OF KEY FACTORS AND EVENTS

2026-07-01T12:24:31+00:00

This paper analyzes key factors and events in the 21st century that have determined the dynamics of crude oil and natural gas prices on the global market. Particular emphasis is placed on geopolitical and macroeconomic factors that have influenced shifts in supply-demand balance, as well as the emergence of increased volatility in energy markets. The study examines the Iraq War and the U.S. military intervention, the Arab Spring, the COVID-19 pandemic, the Russia-Ukraine war, and contemporary tensions between the United States, Israel, and Iran. These events, through disruptions in production, transportation, and global energy flows, have significantly affected price formation and market structures in both oil and natural gas markets. The results indicate that geopolitical and structural factors play a dominant role in shaping both short-term volatility and long-term trends in energy markets, with their effects directly reflected in global economic stability and energy security.

1D ADJUSTMENT OF THE GEODETIC NETWORK AT THE SCHOOL MINE “CRVENI BREG” ON AVALA

2026-07-01T12:24:56+00:00

The objective of this paper is to present the procedure for obtaining the most probable values of height differences through one-dimensional adjustment of the geodetic network of the school mine “Crveni Breg” on Avala. Since the terrain is not connected to the national levelling network, the first step involves determining adjusted height differences. Once the initial point is linked to a national benchmark, accurate elevations of all points within the school polygon will be established. The survey was conducted using the geometric levelling method from the middle ('forward-backward'), and the results were processed by conditional adjustment. Accuracy assessment indicated that the obtained standard deviation corresponds to technical levelling of increased precision, confirming the quality of the fieldwork and measurements.

ENERGY EFFICIENCY OF MODERN UNDERGROUND MINE VENTILATION CONTROL STRATEGIES: A CRITICAL REVIEW OF RESEARCH FINDINGS

2026-07-01T12:25:24+00:00

Underground mine ventilation serves both as a critical safety system and as one of the major consumers of electrical energy in underground mining operations. This paper presents a critical review of the energy performance of ventilation management strategies, focusing on ventilation network optimization, fan speed control, Ventilation-on-Demand (VoD), model-based control, computational fluid dynamics (CFD) applications, and sensor-based monitoring. The review is organized according to the level of intervention and validation, encompassing industrial measurements, pilot-scale and laboratory studies, as well as numerical simulations. The findings indicate that direct energy savings are most commonly achieved through the reduction of network resistance and pressure losses, fan speed adjustment, and the spatial and temporal alignment of airflow distribution with actual operational requirements. CFD analyses and monitoring systems do not constitute energy-saving measures by themselves; rather, they provide the basis for defining safe operating limits and enabling closed-loop control strategies. Reported energy savings are not directly comparable due to differences in baseline operating conditions, system boundaries, and validation methodologies. Reliable implementation requires the maintenance of minimum safety airflow rates, the provision of backup safety measures, and automatic transition to predefined safe operating modes in the event of sensor, communication, or actuator failures.