The fatigue characteristics of rock materials significantly impact the economy and safety of underground structures during construction. Hence, it is essential to conduct further investigation into the progressive damage processes of rocks under cyclic loading conditions. This research utilised both laboratory experiments and discrete element simulations to investigate how confining pressure and fatigue

Gas content serves as a critical indicator for assessing the resource potential of deep coal mines and forecasting coal mine gas outburst risks. However, existing sampling technologies face challenges in maintaining the integrity of gas content within samples and are often constrained by estimation errors inherent in empirical formulas, which results in inaccurate gas content measurements. This study

As coal mining depth increases, the combined effects of high stress, mining stress, and fault structures make dynamic impact hazards more frequent. The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms. Physical simulation test represents an efficacious methodology. However, there is currently a lack of simulation devices that can effectively

The permeability of rocks is of utmost importance in the exploitation of deep geological resources. Current characterizations of rock permeability typically consider the influence of either pores or fractures alone. However, deep reservoir rock formations are subjected to complex environments with coupling of high temperature and stress. As a result, deep reservoir rocks possess a complex structure

Physical analog modeling is an effective approach for studying the hazards of coal bursts in coal similarity criteria for physical and mechanical parameters of the actual and similar materials are crucial to yield realistic results. The derivation of similarity criteria is predominantly based on dimensional analysis, while a systematic methodology has yet to be developed. This paper attempts to fill

With the widespread adoption of hydraulic fracturing technology in oil and gas resource development, improving the accuracy and efficiency of fracturing simulations has become a critical research focus. This paper proposes an improved fluid flow algorithm, aiming to enhance the computational efficiency of hydraulic fracturing simulations while ensuring computational accuracy. The algorithm optimizes

Multistage fracturing technology has been used to enhance tight hydrocarbon resource recovery. Determining the proper well spacing and fracturing strategy is crucial for generating a complex fracture network that facilitates oil and gas flow in reservoirs. The stress-shadow effect that occurs between multiple wells significantly affects the development of fracture networks in reservoirs. However, the

The global reliance on phosphate rock for agriculture and other industries, coupled with chemical regulations in developed countries, has driven the search for green alternatives in apatite flotation. This review investigates eco-friendly collectors’ effectiveness in promoting sustainable mineral processing, guiding future alternatives to traditional reagents. The manuscript discussed the surface properties

Through a case analysis, this study examines the spatiotemporal evolution of microseismic (MS) events, energy characteristics, volumetric features, and fracture network development in surface well hydraulic fracturing. A total of 349 MS events were analyzed across different fracturing sections, revealing significant heterogeneity in fracture propagation. Energy scanning results showed that cumulative

The hydraulic fractures induced in soft coal composite reservoirs have complex extension and energy evolution characteristics. In this study, the mechanism whereby gas outbursts can be eliminated by hydraulic fracturing was revealed. The combined fracturing process of a coal seam and its roof under different in situ stress and fracture spacing conditions was analysed through true triaxial physical

The models constructed by particle flow simulation method can effectively simulate the heterogeneous substance characteristics and failure behaviors of rocks. However, existing contact models overlook the rock cracks, and the various simulation methods that do consider cracks still exhibit certain limitations. In this paper, based on Flat-Joint model and Linear Parallel Bond model, a crack contact

Methane in-situ explosive fracturing technology produces shale debris particles within fracture channels, enabling a self-propping effect that enhances the fracture network conductivity and long-term stability. This study employs X-ray computed tomography (CT) and digital volume correlation (DVC) to investigate the microstructural evolution and hydromechanical responses of shale self-propped fracture

Accurate acquisition of the rock stress is crucial for various rock engineering applications. The hollow inclusion (HI) technique is widely used for measuring in-situ rock stress. This technique calculates the stress tensor by measuring strain using an HI strain cell. However, existing analytical solutions for stress calculation based on an HI strain cell in a double-layer medium are not applicable

Lunar core samples are the key materials for accurately assessing and developing lunar resources. However, the difficulty of maintaining borehole stability in the lunar coring process limits the depth of lunar coring. Here, a strategy of using a reinforcement fluid that undergoes a phase transition spontaneously in a vacuum environment to reinforce the borehole is proposed. Based on this strategy,

In the application of high-pressure water jet assisted breaking of deep underground rock engineering, the influence mechanism of rock temperature on the rock fragmentation process under jet action is still unclear. Therefore, the fluid evolution characteristics and rock fracture behavior during jet impingement were studied. The results indicate that the breaking process of high-temperature rock by

Understanding the anchorage performance of en-echelon joints under cyclic shear loading is crucial for optimizing support strategies in jointed rock masses. This study examines the anchorage effects on en-echelon joints with various orientations using laboratory cyclic shear tests. By comparing unbolted and bolted en-echelon joints, we analyze shear zone damage, shear properties, dilatancy, energy

The generalized rheological tests on sandstone were conducted under both dynamic stress and seepage fields. The results demonstrate that the rheological strain of the specimen under increased stress conditions is greater than that under creep conditions, indicating that the dynamic stress field significantly influences the rheological behaviours of sandstone. Following the rheological tests, the number

Cleat serves as the primary flow pathway for coalbed methane (CBM) and water. However, few studies consider the impact of local contact on two-phase flow within cleats. A visual generalized model of endogenous cleats was constructed based on microfluidics. A microscopic and mesoscopic observation technique was proposed to simultaneously capture gas–liquid interface morphology of pores and throat and

To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata, this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes. The tests involved loading the samples to 60%, 70%, and 80% of their uniaxial compressive strength, followed by unloading and reloading until failure. Key parameters such as the elastic

In the gas-coal integrated mining field, the conventional design method of pipeline coal pillars leads to a large amount of coal pillars being unrecovered and overlooks the pipeline’s safety requirements. Considering the coal pillar recovery rate and pipeline’s safety requirements, two new shaped coal pillar design approaches for subsurface pipelines were developed. Firstly, the deformation limitations

The storage of solid waste in Bayan Obo has resulted in significant resource wastage and environmental concerns. In this study, an efficient process was developed to recover iron and rare earth elements (REEs) from this waste by processes of hydrogen-based mineral phase transformation (HMPT), magnetic separation, and flotation. Under optimal HMPT conditions (525 °C, 12.5 min, and 30% H2 concentration)

Hydraulic fracture (HF) formed in rock significantly helps with the development of geo-energy and geo-resources. The HF formation condition was challenging to understand, with obscure rock micro-cracking mechanisms being a key factor. The rock micro-cracking mechanism under gradient pore water pressure was analyzed on the scale of mineral particles and it was combined with macroscopic boundary conditions

In this paper, the effect of vibration intensity on the spatial distribution of sulfur content in bed particles was studied. The effects of vibration and airflow on the mechanical characteristics of particles were studied, the collision behavior mode of particles was determined, the spatial saltation law of particles was investigated, the spatial functional axis of beds was determined, and the saltation

The attenuation of the acoustic activity in marble specimens under uniaxial compressive loading-unloading loops is quantified in juxtaposition to that of the electric activity. In parallel, the existence of “pre-failure indices” warning about entrance into a critical stage, that of impending fracture, is explored. The acoustic activity is quantified in terms of the normalized number of acoustic hits

The anchoring capacity of the anchor cable is closely related to the bonding length and radial pressure conditions. Through field pull-out tests, theoretical analysis, numerical simulation, and industrial tests, this study clarifies the relationship between radial pressure and bonding length for the ultimate pull-out force and reveals the microscopic failure process of the resin-rock interface in the

The combination of ultrasonic and acid fracturing fluid can strengthen the modification effect on the micropore structure of the coal matrix, thereby enhancing the efficiency of the acid fracturing process. In this research, acetic acid was utilized to formulate acid fracturing fluids with varying concentrations, and the evolutionary traits of both the acid fracturing fluids and ultrasonic waves in

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass. Based on digital speckle correlation (DSCM), acoustic emission (AE) and electromagnetic radiation (EMR), uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry, natural and saturated

The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture (CPF) with different joint roughness coefficients (JRCs). Based

Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets (SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets (AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break

The thermal effects of coal combustion considerably influence the physical and chemical properties, structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. In this study, the impacts of temperature on the physical and chemical characteristics (i.e., mineral phase, microstructure, and mechanical strength) of sandstone were investigated by

Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering

To more accurately describe the coal damage and fracture evolution law during liquid nitrogen (LN2) fracturing under true triaxial stress, a thermal–hydraulic-mechanical-damage (THMD) coupling model for LN2 fracturing coal was developed, considering the coal heterogeneity and thermophysical parameters of nitrogen. The accuracy and applicability of model were verified by comparing with LN2 injection

Tin is a critical metal for various industries, making its recovery from low-grade cassiterite ores crucial. This study aimed to optimize the flotation recovery of cassiterite using multi-component collector systems. Several collectors were initially selected through micro-flotation tests, leading to the identification of optimal proportions for a four-component collector system (SHA-OHA-SPA-DBIA in

The deformation energy (Wd) of soil-like tectonic coal is crucial for investigating the mechanism of coal and gas outbursts. Tectonic coal has a significant nonlinear constitutive relationship, which makes traditional elastic-based models for computing Wd unsuitable. Inspired by critical state soil mechanics, this study theoretically established a new calculation model of Wd suitable for the coal with

As mining activities expand deeper, deep high-temperature formations seriously threaten the future safe exploitation, while deep geothermal energy has great potential for development. Combining the formation cooling and geothermal mining in mines to establish a thermos-hydraulic coupling numerical model for fractured formation. The study investigates the formation heat transfer behaviour, heat recovery

In this study, to better decide the effect of coal seam dip angle upon the dynamic change of the cross-fusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam, a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture. The results demonstrated

To elucidate the yielding performance of compact yielding anchor cables in working state, a yielding mechanical model incorporating extrusion friction and fastening rotation under confining pressure is constructed. The yielding resistance enhancement effect (ω) caused by working environment constraints is evaluated through multi-layer composite sleeve hole expansion analysis, forming a theoretical

With resource exploitation and engineering construction gradually going deeper, the surrounding rock dynamic disaster becomes frequent and violent. The anchorage support is a common control method of surrounding rock in underground engineering. To study the dynamic damage characteristics of anchored rock and the energy absorption control mechanism of dynamic disasters, a new type of constant resistance

Salt cavern energy storage technology contributes to energy reserves and renewable energy scale-up. This study focuses on salt cavern gas storage in Jintan to assess the long-term stability of its surrounding rock under frequent operation. The fatigue test results indicate that stress holding significantly reduces fatigue life, with the magnitude of stress level outweighing the duration of holding

Herein, a first-principles investigation was innovatively conducted to research the surface oxidation of ZnS-like sphalerite in the absence and presence of H2O. The findings showed that single O2 was preferred to be dissociated adsorption on sphalerite surface by generating SO and ZnO bonds, and the S atom on the surface was the most energy-supported site for O2 adsorption, on which a ZnOSOZn structure

Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines. This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating (RMR). Considering a low-grade metal mine as an example, this study exploited geostatistical methods to obtain independent RMR for each block unit. A three-dimensional

With the rise of artificial intelligence (AI) in mineral processing, predicting the flotation indexes has attracted significant research attention. Nevertheless, current prediction models suffer from low accuracy and high prediction errors. Therefore, this paper utilizes a two-step procedure. First, the outliers are processed using the box chart method and filtering algorithm. Then, the decision tree

With the increase of underground engineering construction depth, the phenomenon of surrounding rock sudden failure caused by supporting structure failure occurs frequently. The conventional unloading confining pressure (CUCP) test cannot simulate the plastic yielding and instantaneous unloading process of supporting structure to rock. Thus, a high stress loading-instantaneous unloading confining pressure

The sublevel top coal caving (SLTCC) mining technology is extensively employed in steeply inclined thick coal seams. Because of the typical characteristics of the short coal face in this mining method, a significant portion of the top coal is lost at the face end. For reducing the coal loss, the partially reverse drawing technique (PRDT) is proposed as a novel top coal drawing technique. Meanwhile

The intricate interplay between rock mechanics and fracture-induced fluid flow during resource extraction exerts profound effects on groundwater systems, posing a pivotal challenge for promoting green and safe development in underground engineering. To address this, a novel numerical model with an explicit coupling simulation strategy is presented. This model integrates distinct modules for individual

The rapid advancement of gas sensitive properties in metal oxides is crucial for detecting hazardous gases in industrial and coal mining environments. However, the conventional experimental trial and error approach poses significant challenges and resource consumption for the high throughput screening of gas sensitive materials. Consequently, this paper introduced a novel screening approach that integrates

A series of flexible and self-standing coal-derived carbon fibers (CCFs) were fabricated through electrospinning coupled with carbonization using bituminous coal and polyacrylonitrile (PAN) as the carbon precursors. These CCFs were utilized as free-standing lithium-ion battery (LIB) anodes. Optimizing carbonization temperature reveals that the CCFs exhibit a one-dimensional solid linear structure with

The axial direction of a roadway often forms a certain spatial angle with the in-situ stress field. Variations in the spatial angles can lead to differences in the stress environment in which the roadway is exposed. Different forms of failure characteristics occur in the roadway. In order to study the failure mechanism with different spatial characteristics, rock-like material specimens with holes

Cyclic impact induces ongoing fatigue damage and performance degradation in anchoring structures, serving as a critical factor leading to the instability of deep roadways. This paper takes the intrinsic spatiotemporal relationship of macro-microscopic cumulative damage in anchoring structures as the main thread, revealing the mechanism of bearing capacity degradation and progressive instability of

The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate, resulting in unsatisfactory flotation performance. To enhance the surface reactivity of hemimorphite with sulfidizing agents and xanthate, Cu/Pb binary metal ions were introduced into the sulfidization flotation system to enhance the sulfidization process and thereby promote hemimorphite flotation

The clay mineral flocculation encapsulation poses a major technical challenge in the field of fine mineral separation. Enhancing the ability to separate clay minerals from target mineral surfaces is key to addressing this issue. In the flotation process of ultrafine hematite, sodium polyacrylate (PAAS) was used as a selective flocculant for hematite, polyaluminum chloride (PAC) as a flocculant for

The complex and special mechanical properties of Xiyu conglomerate are of great significance to the construction of water conservancy and hydropower engineering. The crack characteristic stress, dilatancy behavior, and failure mechanism of Xiyu conglomerate collected from Momoke Water Control Project, southwestern China, were analyzed and discussed based on the experimental results of triaxial compression

The surface/interfacial reactivity of clay is a critical factor influencing the sedimentation of coal slurry water. To achieve efficient sedimentation of coal slurry water, this paper introduces a novel approach that regulates the hydrophobicity of defective active sites in clay minerals. Fe3+-doped kaolinite (Fe3+-Kao) was synthesized by hydrothermal methods. Subsequently, tests were conducted on

The electromagnetic radiation (EMR) monitoring and early warning technology has experienced decades of successful applications for worldwide coal and rock dynamic disasters, yet a fundamental model unifying physical mechanism and generation process for EMR is still lacking. The effective revealing of EMR’s mechanism is crucial for dynamic disaster control and management. With this motive, a multi-scale

Achieving low-carbon development in the mining sector is fundamental for global carbon emissions abatement, especially considering the growing demand for mineral resources. Currently, the energy footprint of mines emerges as the main carbon contributor. While cleaner energy sources have the potential for reducing emissions, transitioning to these sources remains challenging. This study presents a practical

Achieving efficient flotation separation of chalcopyrite and galena while maintaining environmental friendliness poses a challenge. This study utilized the environmentally friendly copolymer acrylic acid-2-acrylamide-2-methylpropanesulfonic acid (AA/AMPS) as a depressant to separate chalcopyrite and galena. Flotation tests revealed a significant reduction in galena recovery when AA/AMPS was employed

The fluidity of coal-water slurry (CWS) is crucial for various industrial applications such as long-distance transportation, gasification, and combustion. However, there is currently a lack of rapid and accurate detection methods for assessing CWS fluidity. This paper proposed a method for analyzing the fluidity using videos of CWS dripping processes. By integrating the temporal and spatial features

Cementitious gangue-fly ash backfill (CGB) is used as a green mining technology worldwide. However, under the coupled effects of geological stress and groundwater, the metal elements in the CGB tend to migrate into nearby strata, which can consequently result in pollution of the groundwater environment. In this paper, the influence of initial pH and stress damage on the migration behavior of metal

Rare earth elements have been widely applied in various sectors. Bastnaesite and monazite are crucial rare earth minerals, and flotation is a vital technique for recovering fine-grained rare earth minerals and separating them from associated gangue minerals such as fluorite and apatite. Flotation collectors play a key role in selectively adsorbing valuable minerals, enhancing their surface hydrophobicity

Both bulk stress (σii) and stress path (SP) significantly affect the transportation characteristics of deep gas during reservoir pressure depletion. Therefore, the experimental study of horizontal stress unloading on seepage behavior of gas-bearing coal under constant σii-constraints is performed. The results show that coal permeability is affected by horizontal stress anisotropy (σH≠σh), and the contribution