The paper presents a novel method for upscaling geological model grids of hydrocarbon reservoirs, particularly well-suited to highly heterogeneous formations. To determine the optimal number of layers in the upscaled model, the Lorenz coefficient was used. A rapid decline in its value was interpreted as a significant loss of geological information, providing a quantitative criterion for limiting vertical coarsening. Hydraulic Units (HU) were calculated based on the analysis of Reservoir Quality Index (RQI) and Flow Zone Indicator (FZI) parameters. These units served as the basis for transforming the reference model into a rock-type model. Advanced image comparison techniques based on deep artificial neural networks were used to compute the similarity between adjacent layers. This enabled the identification and merging of geologically similar layers while preserving the reliability of the upscaled model. The proposed method outperforms conventional upscaling approaches in terms of both accuracy and computational efficiency. Notably, it eliminates the need for time-consuming optimisation procedures, which are commonly required in standard workflows. Furthermore, the developed algorithm is grounded in robust theoretical principles related to reservoir rock classification and allows continuous improvement of results via retraining or replacement of the image analysis module.
Tunnel excavation by drill and blast requires creating an effective opening cut to provide a free surface for subsequent rock breakage. While numerous studies have examined blast design parameters, the exact shape and dimensions of the rock volume assigned to each blasthole have yet to be recognised as critical variables. This study introduces the angle of breakage as a measurable parameter and evaluates its influence on tunnel advance efficiency in blast rounds with parallel-hole cuts. More than 60 tunnel blast designs, as recorded in the Atlas of Blasting Rounds for Tunnel Driving, were analysed. The angles of breakage were determined from blast layouts by using CAD tools and following the delay sequence. Only holes with defined initiation timing were considered. Contour holes and simultaneous delays were excluded. For each blast, the average angle of breakage was calculated and correlated with advance efficiency, defined as the ratio between actual pull (PR) and designed pull (PD). Measured angles ranged from 35° to 140°, with typical industrial averages above 50°. The results show a clear inverse relationship between the average angle of breakage and advance efficiency. A threshold behaviour was identified at approximately 60°, above which efficiency decreases systematically. The highest efficiencies were observed for average angles near 65°. Statistical analysis indicates that the angle of breakage presents a stronger correlation with efficiency (R² up to 0.67 for homogeneous lithological sets) than conventional design parameters such as burden, spacing, powder factor, or hole diameter. Three lithological clusters were identified. A heterogeneous set shows scattered behaviour. A second set, representing the majority of cases across mixed lithologies, exhibits a consistent inverse trend. A third set, composed mainly of competent intrusive igneous rocks, displays a more defined correlation between increasing angle and decreasing efficiency. These results indicate that lithology modulates the sensitivity of efficiency to geometric design parameters. The findings demonstrate that the angle of breakage is a relevant design variable for tunnel blasting. Increasing the angular width of the rock prism assigned to each blasthole increases resistance to breakage and reduces advance efficiency. Blast designs based on narrower angles of breakage provide more favorable conditions for rock fragmentation and displacement. The results support the inclusion of this parameter in blast design methodologies and in the interpretation of tunnel excavation performance.
The article discusses the relationship between mineralogical and petrographic properties and the wear resistance (abrasiveness) and abrasive characteristics (abrasivity) of natural stones. Abrasiveness is critical for the durability and functionality of these materials in construction applications. In contrast, rock abrasivity is assessed in the context of tool wear during stone processing. The research focuses on the mineralogical and petrographic characteristics of various types of natural stones, such as sandstones, granites, dolomites, and limestones, and their impact on the mechanical properties of these rocks. The article presents the results of laboratory tests that determine the degree of rock abrasivity and abrasiveness of natural stones, which is essential for selecting appropriate materials for specific construction purposes. The Böhme Abrasion Wheel Tester was used to assess rock abrasiveness, while the proprietary AGH abrasivity test was employed to evaluate rock abrasivity. The type of minerals within the stone's structure and the nature of the mineral binder directly affect the strength and abrasive properties of natural stones. The article also highlights the importance of material homogeneity and porosity in wear resistance.
The present study investigates the potency of stabilising a problematic Black Cotton (BC) soil using a combination of coal tailings and calcium lignosulphonate to address the subgrade problems of a part of the Narsapur-Aswaraopeta major highway. The BC soil creates problems in the construction and maintenance of road pavements in this region. An exhaustive experimental programme was performed on treated BC soil to evaluate the impact of distinct Coal Tailings of 0-20% and Calcium Lignosulfonate of 0-5% dosage. The results revealed that the optimal combination of 12% Coal Tailings and 4% Calcium Lignosulfonate yielded a rise in Maximum Dry Density, California Bearing Ratio, and Unconfined Compressive Strength of the treated soil. These improvements are attributed to the development of Calcium Silicates and Calcite, as established through X-Ray Diffraction analysis and densification of the soil matrix observed through Field Emission Scanning Electron Microscopy. The Energy-Dispersive X-Ray Spectroscopy showed the alterations in primary composition, indicating the interaction between stabilisers and the BC soil. The analysis made on the optimum CBR value with corresponding pavement thicknesses revealed that the pavement thickness with the combinedly treated BC soil was greatly decreased to 290 mm. The combined stabilisers treatment proved significantly more effective than individual stabilisation methods, offering a promising approach for improving the geotechnical characteristics of challenging BC soil for subgrade construction and other geotechnical applications.
In most coal mines across Europe, mining operations have already ceased, and the previously exploited geological strata have become partially or fully flooded. The process of mine flooding is gradual, often spanning several years or even decades. During this time, the water table within the re-saturating rock mass slowly rises toward the surface. As groundwater infiltrates and saturates the rock, it induces geomechanical changes, including the movement of rock blocks within the geological strata and the redistribution of local gravitational stresses. These changes result in stress accumulation and alterations in the geodynamic equilibrium of the region. Ultimately, such processes can lead to large-scale ground movements, including land subsidence, uplift, or the sudden formation of sinkholes in near-surface areas. Understanding and monitoring these phenomena are critical for mitigating geohazards associated with post-mining environments and ensuring the long-term stability of former mining regions. To support this goal, a study was conducted to predict surface uplift at the flooded Kazimierz-Juliusz coal mine in Poland using numerical modelling with FLAC2D, a finite difference method-based software. Based on extensive Satellite Radar Interferometry (InSAR) monitoring data, a numerical model was developed and subsequently verified for predictive analysis. Occurrence of surface uplift has been observed at the studied site, with a maximum displacement of approximately 16 cm at the end of 2023. Long-term predictions indicate that surface uplift could reach up to 57 cm when the water level rises to ground level. This research is expected to provide a valuable reference for understanding uplift phenomena and to contribute to a deeper insight into water-mechanical interactions within the rock mass in regions affected by mine flooding.
