Abstract The fire gas behaviour involving multiple fires in a mine drift with longitudinal ventilation was analysed, focusing on the phenomena occurring upstream of the fires. The analysis was based upon experimental data from model-scale fire experiments. Multiple fire source scenarios will for identical heat release rates result in higher upstream fire gas temperatures at the ceiling level and longer backlayering distances compared to a single fire source scenario. The explanation of the higher upstream fire gas temperatures can likely be found in the changed flame behaviour downstream of the multiple fire sources. Correlations for the upstream ceiling fire gas temperature - accounting for the conditions in a mine drift with multiple burning objects - were proposed. The results of the analysis will improve the understanding of, and the mitigation measures taken when facing multiple fire sources in a mine drift.
Abstract This paper presents an integrated analysis of the structural durability of an excavator boom, a critical component subjected to extreme cyclic loads in the harsh mining environment of Roșia Poieni quarry. The study combines a numerical approach based on the Finite Element Method (FEM) with the theoretical principles of fatigue analysis to evaluate the stress state, estimate the remaining service life, and determine the safety factor. The FEM analysis, applied to a hybrid shell-beam model of the Hitachi EX1000 excavator boom, revealed critical stress concentrations in connection and welding zones, confirming these points’ vulnerability to fatigue failure. Based on the stress values extracted from the simulation, Wöhler curve (S-N curve), adjusted with specific environmental (corrosion) and reliability factors, was used to estimate the service life. The results indicated a number of cycles to failure of approximately 3.98×10 4 and an estimated mean time to failure of 4457.14 hours, which signals a high risk of premature failure. A supplementary evaluation using the Goodman diagram confirmed this risk, calculating a safety factor of 1.49, a value below the recommended standards for dynamic applications. The study concludes that the boom operates in a potentially unsafe regime and proposes a series of practical recommendations to improve its reliability. These include implementing Condition-Based Monitoring (CBM) systems, optimizing the structural design in critical areas, and intensifying anti-corrosion protection programs.
Abstract Goal. To reduce the level of adverse factors in the air at quarry working benches by using localized ventilation systems powered by alternative energy sources. Research methods. Theoretical substantiation of the system configuration and approximate parameters of the components of a localized ventilation system for quarries. Scientific novelty. For the first time, a system is proposed that extracts polluted air from the quarry recirculation zone, partially cleans it, and subsequently disperses it outside the quarry, using solar energy to generate airflow in a ventilation duct. Practical significance. The results can be applied in the design and modernization of localized ventilation systems in deep quarries to reduce gas and dust concentrations in working areas, which will lower energy costs, reduce greenhouse-gas emissions, improve occupational safety, and decrease anthropogenic impacts on the environment. The results. A mobile localized ventilation system for deep quarries based on solar-induced buoyancy-driven draft is developed and theoretically substantiated. Analytical relationships are obtained to estimate airflow velocity and pressure depression in the ventilation duct, and the effectiveness of reducing gas and dust concentrations in working areas is demonstrated. The proposed solution shows potential to improve environmental and occupational safety while reducing energy consumption.
Abstract On July 21 st 2025, a flow of rocks mixed with water took place in Coștiui (Maramureș), from the surface, in the underground excavations of Ferdinand mine (which operated between 1828-1934), at the limit of its southern shaft, which generated on the surface, in the southern vicinity of the county road DJ 186A, a collapse cone of approx. 1500m 3 . The article develops the geo-mechanical phenomenon and the causes that led to the occurrence of this spontaneous phenomenon, the rehabilitation measures and the safety of the affected area.
Abstract Mining activities in the Jiu Valley coal basin have generated substantial volumes of waste materials, and Ramura 1, 2, 3 and 4 tailings dump in the Petrila area represents a continuously evolving geochemical system. This study examines the temporal trends of heavy metals (Cr(total), Cu, Ni, Zn, Co, Pb) and associated geochemical parameters (pH, Eh, moisture, organic matter, electrical conductivity) over the 2022–2024 period, using standardised determinations and year-to-year comparative analysis. The results indicate progressive increases in Cr (total), Cu and Ni (3–7% annually), while Zn remains consistently elevated but relatively stable. Geochemical parameters reveal gradual acidification (pH 6.72 → 6.31) and increasingly oxidising conditions (Eh 312 → 342 mV), both favouring the mobilisation of redox-sensitive metals. Comparison with Romanian Regulation Order 756/1997 shows no exceedance of intervention thresholds; however, several metals surpass normal values or approach alert thresholds. Overall, the findings confirm the dynamic nature of Ramura 1–4 tailings dump and highlight the need for continued long-term monitoring to assess environmental risks and to support informed post-mining management strategies.
