The article presents the results of phase transition studies in which the following substances and their mixtures were tested: 100% palm oil, 100% paraffin, 100% hydrogenated palm oil, 50% palm oil + 50% paraffin, 50% hydrogenated palm oil + 50% palm oil, 33% hydrogenated palm oil + 33% palm oil + 33% soft paraffin, 20% hydrogenated palm oil + 30% palm oil + 50% soft paraffin, 50% hydrogenated palm oil + 50% palm oil + copper, and 50% hydrogenated palm oil + 50% palm oil + iron. The measurements were carried out on a station for testing phase-change materials (PCMs) designed specifically for the analysis of phase changes. Viscosity values were also determined for the tested materials, and their potential impact on heat accumulation was assessed. The primary goal of the experiment was to determine some key thermodynamic parameters, including transition time, transition heat, specific heat, and dynamic viscosity at 58 °C. A one-way ANOVA test confirmed the statistical significance of minimum transition temperature, maximum transition temperature, and phase transition time, validating the reliability and utility of the results. The melting point, crucial for applications involving phase changes, was identified as an important factor. The careful selection of components allows for the customization of properties tailored to specific applications. A significant result is that the analyzed substances with higher specific heat values tend to have a higher average dynamic viscosity. The Pearson correlation coefficient of 0.82 indicated a strong positive association between the average dynamic viscosity and the heat of fusion of the substances examined. This suggests that changes in the heat of fusion significantly influence alterations in dynamic viscosity. Substances with higher specific heat values tend to exhibit higher average dynamic viscosity, emphasizing the direct impact of composition on viscosity.

This article addresses the issue of the durability of mining shaft equipment elements. Shafts as a transport route are one of the most exploited parts of a mine. Consequently, their components are exposed to high mechanical stresses, which cause the deterioration of their mechanical properties. In the case of shafts with timber components, elements such as the shaft guides are evaluated on a purely macroscopic basis and are often unnecessarily replaced. This paper presents the possibilities for the application of non-destructive methods (ultrasound and laser scanning) and semi-destructive methods (sclerometric and drill resistance tests). The experimental results suggest that it was possible to derive correlations between penetration depth and drill resistance tests with bulk density. However, these tests were not directly correlated with flexural strength. The ultrasound studies did not indicate a significant relationship with the physical or mechanical properties. In contrast, the method of comparing the variation (wear) in the tested guides using 3D laser scanning demonstrated a high accuracy; moreover, this method is independent of factors that may affect the results of penetration depth or drill resistance measurements. The application of non-destructive and semi-destructive tests for the determination of the physical and mechanical properties of timber elements of mine shafts’ equipment may enable the detection of a defect earlier or extend the service life of elements, hence limiting the downtime of shaft operation related to the replacement of elements.

This paper combines empirical observations, kinematic analysis, and numerical simulation to investigate slope failure susceptibility, with practical implications for regional infrastructure projects. Six slopes along the R37 road were analyzed to assess the impact of strata orientation and water presence on slope stability. The results indicate that various factors interact to destabilize the mechanical integrity of both rock and soil materials. Dry slopes were found to be less vulnerable to failure, although geological conditions remained influential. Numerical modeling using FLACSlope (version 8.1) revealed that the factor of safety (FoS) decreases as the water presence increases, highlighting the critical need for effective drainage solutions. Kinematic analysis, incorporating DIPS modeling and toppling charts, identified toppling as the most likely failure mode, with a 90% susceptibility rate, followed by planar and wedge failures at 6% and less than 5%, respectively. These findings are validated by the observed slope conditions and empirical data. Planar failures were often remnants of both sliding and toppling failures. Given the significant risk posed to road infrastructure, particularly where FoS hovers just above the stability threshold, this study emphasizes the importance of proactive, long-term slope monitoring and early mitigation strategies to prevent catastrophic failures. The results can guide infrastructure design and maintenance, ensuring safer and more resilient roadways in regions prone to slope instability. Nonetheless, the use of sophisticated slope stability modeling techniques is recommended for a thorough understanding of the mechanical dynamics of the slope material, and for catering to the shortfalls of the techniques applied in this paper.

As the reserves of these raw materials continue to dwindle, their extraction is becoming increasingly difficult, with shaft depth increasing and sometimes exceeding three kilometres. As shaft depths increase, the costs, as well as the risks of mining and other shaft operations, increase non-linearly. There is also a significant increase in the costs associated with condition assessment, which depend on the inspection and testing method used and increase with the lifetime of the facility. New technical and organisational solutions are emerging to meet these requirements. This paper addresses the operation of steel ropes. This article analyses the results of strength tests on two selected modern hoisting rope designs that have recently come into service. These structures are relatively unknown to users in terms of their wear. In their operation, significant problems of condition assessment and safety, as well as disqualification due to the level of wear reached, arise. Strength tests were performed using classic non-destructive methods (tensile test, torsion test, bending test) to assess the technical condition of ropes after their replacement. The tests on two rope structures carried out before and after they were put down by expert decision were analyzed. The results of these tests were statistically processed and presented graphically to determine similarities and differences. Statistical analyses were used to evaluate the results by examining the distribution of variable strength parameters. All results were commented on, and specific and general conclusions were drawn. The article presents the conclusions, the most important of which is that new and complex ropes exhibit varying degrees of wear across the layers. This is due to their compaction process. These should be useful to users of similar rope designs, personnel carrying out the obligatory tests imposed by the legislation, and those making strategic decisions regarding the operation of entire mining plants. The analyses may contribute to the subsequent assessment of the technical condition of new ropes, which in many cases have wear parameters (corrosion, strength loss, etc.) assessed in a subjective, not quantitative, manner.

Using biogas fuel in a modern internal combustion engine equipped with gas equipment of the fourth and fifth generations can create several difficulties. This is due to the low heat of combustion of untreated biogas, the presence of moisture, and the specifics of the injectors. The main problem of the studies we considered is that there are no data on the operating parameters of biogas fuel injectors. Studies on the parameters of the Matrix, Barracuda, Valtek, Hana, and Keihin injectors in relation to biogas fuel were carried out according to performance indicators, the linearity of operation, the resistance of the injectors, the ability to maintain factory parameters, and service life. According to the indicators of performance and linearity of work, Valtek injectors have the highest deviation in productivity and linearity of work, with an average of 38.8%, and the lowest deviation of Barracuda injectors is 7.5%. Keihin (15.3%) and Hana injectors (19.1%) also showed good performance indicators, and therefore can be used effectively for biogas fuel systems. As a result of research on the response time of the injectors, it was established that the best indicators were found for Hana (1.75 ms) and Keihin (1.99 ms) injectors. Valtek injectors showed good response rates (2.07 ms), as did Barracuda injectors (2.19 ms), but the highest response time was found in Matrix injectors, with 2.44 ms. Keihin injectors had the lowest average resistance value of 1.25 ohms, and Valtek injectors had the highest resistance value of 3 ohms. According to the research results, Keihin, Matrix, and Barracuda injectors provide the best ability to maintain factory performance when using biogas fuel at 2 to 5%, and Valtek had the worst performance up to 20%. Keihin, Barracuda, and Hana experimental injectors had the highest service life, which is from 200 to 250 thousand km of car mileage. The lowest indicators were found for Valtek and Matrix injectors, the service life of which varies from 70 to 100 thousand km of mileage.

This article describes a certain stage of work aimed at strength analysis of the structure of drive sheaves in mine shaft hoists. The work was initiated in connection with the emergence of cracks in those sheaves as a result of operation, and is an attempt to develop a new improved design of the drive sheave. The first stage involved several series of strain gauge measurements of stress in the drive sheaves of machines exposed to their rated load. Measurement technology and results are described in detail in (Rokita & Wójcik, 2013). The results of those measurements were the basis for FEM stress analysis and discussion of the changes in the structure of those sheaves. This article focuses on a description of the developed computational models for the currently used sheaves, and presents the results of strength calculations. As a result of those actions, a new drive sheave design was developed, for which a computational model was also prepared and FEM calculations were performed. Comparison of the results of calculations for both sheave models is, therefore, also an assessment of the impact of the proposed changes to the design of the drive sheave on its strength and durability. It was decided to adopt the results of strength analysis of the sheave assembly currently in service as the baseline for this assessment. This required not only the performance of a strength analysis on the basis of a specially developed drive sheave calculation model, but also identification and assessment of the allowable stress values for the analysed structure.