As the increasing demand for deep mineral resource extraction and the construction of deep vertical shafts by the artificial ground freezing method, the stability and safety of shaft that traverse thick alluvial depend significantly on their interaction with the surrounding deep frozen soil medium. Such interaction is directly conditioned by the mechanical properties of the deep frozen soil. To precisely capture these in-situ mechanical properties, the mechanical parameters tests using remodeled frozen specimens cannot ignore the disparities in consolidation history, stress environment and formation conditions between the deep and shallow soils. This study performs a series of long-term high-pressure K0 consolidation (where K0 represents the static earth pressure coefficient, describing the ratio of horizontal to vertical stress under zero lateral strain conditions), freezing under sustained load and unloading triaxial shear tests utilizing remodeled deep clay. This study presents the response of unloading strength and damage properties under varying consolidation stresses, durations, and freezing temperatures. The unloading strength increases sharply and then stabilizes with consolidation time. The unloading strength shows an approximate linear positive correlation with the consolidation stress, while a negative correlation with the freezing temperature. The strengthening rate of the unloading strength due to freezing temperature tends to decrease with increasing consolidation time. Additionally, an improved damage constitutive model was proposed and validated by incorporating the initial K0 stress state and a Weibull-based assumption for damage elements. Based on the back propagation (BP) neural network, a prediction method for the stress-strain curve was offered according to the consolidation stress level, initial stress state, and temperature. These results can provide references for improving the mechanical testing methods of deep frozen clay and revealing differences in mechanical properties between deep and shallow soils.

A significant amount of open-pit-mine broken sandstone (OMBS) is produced during open-pit mining. The mechanical strength of the loose sandstone is critical for ensuring dump slope stability and sustainable mine construction. This study investigates the modification of OMBS using artemisia sphaerocephala krasch (ASK) gum to enhance its engineering properties. Unconfined compressive strength, shear strength and permeability tests were conducted to quantitatively analyze the modification effect. And the stability was evaluated using FLAC3D simulation methods. The modification mechanism was characterized through SEM, FT-IR, XRD. The results demonstrated that the addition of 2 % ASK gum significantly improved OMBS mechanical performance and reduced permeability. Meanwhile, the failure mode of OMBS changed with the ASK gum content increasing. The simulation result indicated the stability of modified dump slope was better under the drying-wetting cycle. From the perspective of microstructure and chemical characteristics, the addition of ASK gum created new hydrogen bonds through intermolecular interactions with the hydrophilic groups between OMBS particles and formed a dense and stable structure through three reinforcement modes: surface encapsulation, pore filling, and bonding connection. This study provides a new idea for resource saving and environmentally friendly mining area development.

This study investigates the physicochemical properties of Soil-Like Material (SLM) recovered from aged Municipal Solid Waste (MSW) dumps in Anantapur, Andhra Pradesh, India, and assesses its potential for reuse. The SLM, which constitutes 68%-75% of the excavated waste, was analyzed for key parameters including total dissolved solids (TDS), chemical oxygen demand (COD), electrical conductivity (EC), and heavy metal concentrations. Results revealed that the organic content of SLM ranged from 6% to 20%, significantly higher than that of local soils (1.5%). The leachate produced from SLM showed elevated levels of TDS (500-1,200 mg l-1), COD (150-270 mg l-1), and heavy metals such as copper (Cu), lead (Pb), chromium (Cr), and zinc (Zn). Cu and Pb concentrations were found to be 27 and 26 times higher than those in local soil extracts, posing substantial risks to groundwater and soil quality. Other metals, including nickel (Ni), arsenic (As), and cadmium (Cd), also exceeded permissible limits. These findings suggest that while SLM has potential for reuse, its high contamination levels require treatment methods such as soil washing, heating, or stabilization with additives like lime or fly ash to reduce environmental risks. Without proper treatment, the direct use of SLM could result in substantial ecological damage. The study highlights the importance of sustainable landfill site rehabilitation and the development of safe strategies for the reuse of SLM to mitigate potential environmental impacts.

The southern regions of China are rich in ion-adsorbed rare earth mineral resources, primarily distributed in ecologically fragile red soil hilly areas. Recent decades of mining activities have caused severe environmental damage, exacerbating ecological security (ES) risks due to the inherent fragility of the red soil hilly terrain. However, the mechanisms through which multiple interacting factors influence the ES of rare earth mining areas (REMA) remain unclear, and an effective methodological framework to evaluate these interactions dynamically is still lacking. To address these challenges, this study develops an innovative dynamic ES evaluation and earlywarning simulation framework, integrating Variable Weight (VW) theory and the Bayesian Network (BN) model. This framework enhances cross-stage comparability and adapts to evolving ecological conditions while leveraging the BN model's diagnostic inference capabilities for precise ES predictions. A case study was conducted in the Lingbei REMA. The main findings of the study are as follows: (1) From 2000 to 2020, the overall ES of the mining area exhibited a dynamic trend of deterioration, followed by improvement, and ultimately stabilization. (2) Scenario S27 (high vegetation health status and high per capita green space coverage) significantly reduces the probability of the ES reaching the extreme warning level. (3) The evaluation and simulation framework developed in this study provides a more accurate representation of the ES level distribution and its variations, with probabilistic predictions of ES demonstrating high accuracy. This study is of great significance for improving regional ES, supporting the optimization of ecological restoration strategies under multi-objective scenarios, and promoting the coordinated development of nature and resource utilization.

Collapse pits are highly susceptible to secondary hazards such as underground debris flows and slope instability under mining disturbances. These hazards significantly damage the ecological environment of the mining area. To reduce the geological hazards of collapse pits, grouting is used for management. The diffusion pattern and curing mode of slurry under different grouting pressures were investigated through indoor grouting simulation tests, and industrial tests were carried out to assess grouting effects. The results indicate that the slurry is dominated by penetration diffusion and supplemented by splitting diffusion in the moraine. The penetration distance and diffusion radius of the slurry increase linearly with grouting pressure, while the splitting uplift distance and cured volume increase exponentially with grouting pressure. Splitting diffusion consists of three stages: bulging compaction, splitting flow, and passive uplift. Horizontal splitting has a vertical uplift effect on the formation. The slurry primarily consolidates individual moraine particles into a cohesive mass by filling fractures, binding soil particles, and reinforcing interfaces with the rock mass. For different moraine layer structures, full-hole, segmented, and point-based grouting methods were applied. A composite grouting technique, layered grouting with ring solidification, was also introduced, achieving excellent grouting results. This study provides technical support for managing geological hazards in collapse pits caused by block caving mining disturbances and for green mining practices.

Improving soil properties by adding stabilizing materials, such as cement, has garnered significant attention from researchers, particularly for enhancing soils often deemed poor geotechnical quality. This approach becomes even more advantageous when applied to increase the stability of mining tailings deposits and ensure environmental safety. This study investigates the effects of cement addition and dry density on the strength and durability of compacted bauxite tailings-cement blends. The porosity/cement index, widely used in soil-cement mixture research, was adopted to analyze the parameters that control the strength and durability of these blends. Results demonstrate that increasing cement content and dry density significantly improves unconfined compressive strength (qu) and reduces accumulated mass loss (ALM) during wet/dry cycles. The porosity/cement index effectively describes the variations in qu and ALM, as expressed by an empirical equation, which can be highly beneficial for the practical application of treated mining tailings as construction materials.

Currently, studies on the permeability evolution characteristics of overlying aquiclude protective layers caused by coal mining focus on single lithological protective layers and assume the permeability coefficient remains constant. However, these studies fail to consider the variation characteristics of the combination protective layer structure and permeability coefficient. Therefore, an analytical method is proposed to study coal seam leakage under mining conditions in the blown-sand beach region based on the structure and permeability coefficient of the combination protective layer. First, the stress path of the overlying combination aquiclude under coal mining disturbance is comprehensively considered. Based on this, triaxial loading and unloading seepage creep experiments are conducted with different proportions of overlying combination aquiclude. The analytical relationship between the permeability coefficient of the samples and loess proportion, stress level, and soil depth in the stress recovery stage is determined, leading to the establishment of a creep permeability coefficient evolution model for the overlying combination aquiclude of the coal seam under the stress path of coal mining. Second, the creep permeability coefficient evolution model is integrated with a fusion algorithm in COMSOL numerical simulation software. Numerical simulations are then performed to examine the evolution law of phreatic leakage during coal seam mining and recovery, revealing a relationship curve in which leakage gradually decreases over time before stabilizing in the post-mining recovery stage. Finally, based on mathematical and statistical methods, a phreatic leakage evolution model is developed for both mining and post-mining stages to provide a theoretical basis for environmental protection.

Studying the rheological properties of deep-sea shallow sediments can provide basic mechanical characteristics for designing deep-sea mining vehicles driving on the soft seabed, providing anchoring stability of semi-submersible mining platforms, and assessing submarine landslide hazards. Shallow sediment column samples from the Western Pacific mining area were obtained, and their rheological properties were studied. A series of rheological tests was conducted under different conditions using an RST rheometer. In addition, conventional physical property, mineral composition, and microstructure analyses were conducted. The results showed that shallow sediments have a high liquid limit and plasticity, with flocculent and honeycomb-like flaky structures as the main microstructure types. The rheological properties exhibited typical non-Newtonian fluid characteristics with yield stress and shear-thinning phenomena during the shearing process. In contrast to previous studies on deep-sea soft soil sediments, a remarkable long-range shear-softening stage, called the thixotropic fluid stage, was discovered in the overall rheological curve. A four-stage model is proposed for the transition mechanism of deep-sea shallow sediments from the solid to liquid-solid, solid-liquid transition, thixotropic fluid, and stable fluid stages. The mechanism of the newly added thixotropic fluid stage was quantitatively analyzed using a modified Cross rheological model, and this stage was inferred from the perspective of mineralogy and microstructure. The results of this study can be useful for improving the operational safety and work efficiency of submarine operation equipment for deep-sea mining in the Western Pacific Ocean. (c) 2025 Japanese Geotechnical Society. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Tunnel lining structures, which are subjected to the combined effects of water and soil pressure as well as a water-rich erosion environment, undergo a corrosion-induced damage and degradation process in the reinforced concrete, gradually leading to structural failure and a significant decline in service performance. By introducing the Cohesive Zone Model (CZM) and the concrete damage plastic model (CDP), a three-dimensional numerical model of the tunnel lining structure in mining method tunnels was established. This model takes into account the multiple effects caused by steel reinforcement corrosion, including the degradation of the reinforcement's performance, the loss of an effective concrete cross section, and the deterioration of the bond between the steel reinforcement and the concrete. Through this model, the deformation, internal forces, damage evolution, and degradation characteristics of the structure under the effects of the surrounding rock water-soil pressure and steel reinforcement corrosion are identified. The simulation results reveal the following: (1) Corrosion leads to a reduction in the stiffness of the lining structure, exacerbating its deformation. For example, under high water pressure conditions, the displacement at the vault of the lining before and after corrosion is 4.31 mm and 7.14 mm, respectively, with an additional displacement increase of 65.7% due to corrosion. (2) The reinforced concrete lining structure, which is affected by the surrounding rock loads and expansion due to steel reinforcement corrosion, experiences progressive degradation, resulting in a redistribution of internal forces within the structure. The overall axial force in the lining slightly increases, while the bending moment at the vault, spandrel, and invert decreases and the bending moment at the hance and arch foot increases. (3) The damage range of the tunnel lining structure continuously increases as corrosion progresses, with significant differences between the surrounding rock side and the free face side. Among the various parts of the lining, the vault exhibits the greatest damage depth and the widest cracks. (4) Water pressure significantly impacts the internal forces and crack width of the lining structure. As the water level drops, both the bending moment and the axial force diminish, while the damage range and crack width increase, with crack width increasing by 15.1% under low water pressure conditions.

Mining leads to soil degradation and land subsidence, resulting in decreased soil quality. However, there are limited studies on the detailed effects of mining activities on soil properties, particularly in western aeolian sand. This study, therefore, quantitatively assessed the aeolian sandy soil disturbance induced by mining activities in the contiguous regions of Shanxi, Shaanxi, and Inner Mongolia. The following soil physical quality indices were measured in the pre (May 2015), mid (October 2015), and postmining period (April 2016), such as the soil water content (SWC), particle size (PS), soil penetration (SP), and soil saturated hydraulic conductivity (SSHC). The results showed that mining activities brought irreversible effects on soil structures. In the pre-mining period, land subsidence broke up large soil particles, destroying soil structure, leading to decreased PS (218.33 vs. 194.36 mu m), SP (4615.56 vs. 2631.95 kPa), and subsequently decreased SSHC (1.12 vs. 0.99 cm/min). Rainfall during the midmining period exacerbated this fragmentation. Thereafter, low temperatures and humidity caused the soil to freeze, allowing the small soil particles to merge into larger ones. Meanwhile, the natural re-sedimentation, subsidence, and heavy mechanical crushing in the post-mining period increased PS and SP. The SSHC hence increased to 1.21 cm/min. Furthermore, the evaluation of soil indices from different stress zones showed that the external pulling stress zone always had a higher SSHC than the neutral zone in any mining period, possibly due to the presence of large cracks and high SWC. This study contributes to the understanding of the impact of mining activities on soil physical qualities, providing a theoretical basis and quantitative guidance for the surface damage caused by coal mining in the aeolian sandy area in Western China.