With the increasing scarcity of Earth’s resources and the development of space science and technology, the exploration, development, and utilization of deep space-specific material resources (minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases.

Two critical factors, namely intense precipitation and intricate excavation, can trigger rock mass disasters in mining operations. In this study, an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation. A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep

Users of the digital image correlation method are faced with the problem of poor operability, low repeatability, and lack of standardized specifications for spraying speckles. To solve the problem, the research proposed a rock deformation measurement method that obviates the need to spray speckles. A local binary model was established by using the local binary pattern (LBP) operator based on deep texture

An important index to evaluate the process efficiency of coal preparation is the mineral liberation degree of pulverized coal, which is greatly influenced by the particle size and shape distribution acquired by image segmentation. However, the agglomeration effect of fine powders and the edge effect of granular images caused by scanning electron microscopy greatly affect the precision of particle image

The review covers the development and the state of the art in deep-sea mining rock mechanics, equipment and challenges. It begins by introducing the significance of deep-sea mining, the types and geographical distribution of deep-sea resources. Section 2 reviews the mechanical properties and fracture mechanism of seabed and related continental rocks, which contributes to the advancement of relevant

Abstract not available

Rock mass dynamics disasters caused by excavations and mining occur frequently in deep mines. In order to establish a theoretical system and control technologies for such disasters, we first classify and define dynamic disasters, such as rock bursts, coal bursts, mine pressure bumps, and mine earthquakes. According to the occurrence mechanism of different types of dynamic disasters, we establish a

The significant difference between the mechanical properties of soft rock and hard rock results in the complexity of the failure mode of the anti-dip layered slope with soft and hard rock interbedding. In order to reveal the landslide mechanism, taking the north slope of Fushun West Open-pit as an example, this paper analyzed the failure mechanism of different landslides with monitoring and field surveys

Deep in-situ rock mechanics considers the influence of the in-situ environment on mechanical properties, differentiating it from traditional rock mechanics. To investigate the effect of in-situ stress, pore pressure preserved environment on the mechanical difference of sandstone, four tests are numerically modeled by COMSOL: conventional triaxial test, conventional pore pressure test, in-situ stress

To enhance gas drainage in the soft and hard interbedded (SHI) coal seam, it’s necessary to unload the in-situ stress and improve its gas migration performance. In this research, a directional hydraulic flushing (DHF) technology was carried out. The stress-unloading and gas migration improvement mechanism was analyzed though numerical simulation, and systematic engineering tests were conducted to verify

To investigate the dynamic damage evolution characteristics of bank slopes with serrated structural planes, the shaking table model test and the numerical simulation were utilized. The main findings indicate that under continuous seismic loads, the deformation of the bank slope increased, particularly around the hydro-fluctuation belt, accompanying by the pore water pressure rising. The soil pressure

With the increasing depth of coal mining, the requirements for coring devices that maintain pressure are increasing. To adapt to the special environment in deep coal seams and improve the accuracy of testing gas content, a low-disturbance pressure-preserving corer was developed. The measurement of gas content using this corer was analyzed. The coring test platform was used to complete a coring function

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone (RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters (DDP) and the c-φ

In underground coal mines, fibre reinforced polymer (FRP) bolt is ideal for mined rib reinforcements as it can prevent gas explosions caused by shearer frictional spark. With increasing mining depth, small diameter FRP bolts used in shallow underground mining cannot fulfil the rib support requirements. Under the engineering background of deep underground shortwall mining in Wudong coal mine, this paper

This paper investigates mechanical behaviours of sandstone during post-peak cyclic loading and unloading subjected to hydromechanical coupling effect, confirming the peak and residual strengths reduction laws of sandstone with water pressure, and revealing the influence of water pressure on the upper limit stress and deformation characteristics of sandstone during post-peak cyclic loading and unloading

Chalcopyrite is a common copper-bearing mineral with antiferromagnetic properties. However, this property has rarely been considered in previous studies for detailed adsorption behaviors of molecules on chalcopyrite. Based on density functional theory (DFT), new adsorption pathways by H2O and O2 on the chalcopyrite metal terminated (112) surface ((112)-M) is found in this work. First, through simulating

Abstract not available

Surfactants were proposed to be added into magnesium sulfate solution to improve the leaching process of weathered crust elution-deposited rare earth ores (WREOs). Effects of surfactants and their concentration on the seepage of leaching solutions and the leaching efficiency of rare earth (RE) and aluminum (Al) were investigated, and the leaching kinetics, the mass transfer process, the adhesion work

Twenty-seven specimens were tested to investigate the uniaxial compression behaviour of an innovative standing support for underground space applications. The innovative standing support consisted of an external fibre reinforced polymer (FRP) jacket and the infill column made of cementitious grout, tailings and coal wash rejects. Effects of the FRP layers number and water to the cementitious grout

This paper aims to determine the load bearing capacity of pre-stressed expandable props with different geometries and load eccentricities for flexible support in underground mining or excavation. It is deduced that the expandable device could have much higher strength (>89 MPa) by laboratory tests, and the load bearing capacity of the expandable prop may depend on the stability of the supporting steel

This study investigated the correlations between mechanical properties and mineralogy of granite using the digital image processing (DIP) and discrete element method (DEM). The results showed that the X-ray diffraction (XRD)-based DIP method effectively analyzed the mineral composition contents and spatial distributions of granite. During the particle flow code (PFC2D) model calibration phase, the

The face stability problem is a major concern for tunnels excavated in rock masses governed by the Hoek-Brown strength criterion. To provide an accurate prediction for the theoretical solution of the critical face pressure, this study adopts the piecewise linear method (PLM) to account for the nonlinearity of the strength envelope and proposes a new multi-horn rotational mechanism based on the Hoek-Brown

The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents. An outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test system. We investigated the release characteristics of main energy sources in coal seam, and obtained

Hard rock pillar is one of the important structures in engineering design and excavation in underground mines. Accurate and convenient prediction of pillar stability is of great significance for underground space safety. This paper aims to develop hybrid support vector machine (SVM) models improved by three metaheuristic algorithms known as grey wolf optimizer (GWO), whale optimization algorithm (WOA)

Abstract not available

Chalcopyrite is the main Cu-containing mineral and cannot be separated well from pyrite using traditional xanthate collectors with large amounts of lime depressant, resulting in difficulties of the tailing treatment and associated precious metals recovery. Therefore, in this study, the green and odourless ethylenediamine tetramethylenephosphonic acid (EDTMPA) was introduced as a novel chalcopyrite

Microwave heating contributes to coal fracturing and gas desorption. However, problems of low penetration depth, local overheating and fracture closure exist. Coal demineralisation by acids has advantages in coal unblocking and permeability improvement, while it is difficult for acid to enter microcracks. Microwave-asisted acidification may offer an alternative. In this work, XRD, 1H-NMR, and SEM were

As the poor dispersion of oily collectors and the inferior hydrophobicity of the mineral surface, the low-rank coal has an unsatisfactory flotation performance when using traditional collectors. In this paper, an ionic liquid microemulsion was used as a collector to enhance its floatability. Flotation test results demonstrated the microemulsion collector exhibited a superior collecting ability. A satisfactory

Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only

To improve the rock breaking ability, cavitating waterjet and abrasive waterjet are combined by using a coaxial low-speed waterjet generated around the periphery of a high-speed abrasive waterjet, and a new type of waterjet called unsubmerged cavitating abrasive waterjet (UCAWJ) is thus produced. The rock breaking performance of UCAWJ was compared with submerged cavitating abrasive waterjet (SCAWJ)

In this study, an orthogonal array experiment is conducted by using a transparent fracture network replica. Image processing and theoretical analysis are performed to investigate the model sealing efficiency (SE), factors influencing SE, and the effect of flowing water on propagation. The results show that grout propagation can be classified into three patterns in the fracture network: sealing off

Grinding and flotation processes are often studied independently, despite the well-established grinding influence on flotation performance, which affects not only particle size and thus liberation but also shape and leads to complex changes in pulp chemistry affecting the particle surface properties relevant for selective bubble attachment. Yet, no study jointly investigated these possible causes and

Abstract not available

A plane mechanical model of rock breaking process by double disc cutter at the center of the cutterhead is established based on contact mechanics to analyze the stress evolution in the rock broken by cutters with different spacings. A continuous-discontinuous coupling numerical method based on zero-thickness cohesive elements is developed to simulate rock breaking using double cutters. The process

The lack of understanding of plastic hardening (softening) laws, especially under anisotropic stress conditions, results in inappropriate geotechnical management. Most of the yielding envelopes do not consider the effect of intermediate principal stress and the influence of Lode’s angle. In addition, the application of plastic flow rules regarding yielding surfaces compromises the softening of rock

Deep underground projects (e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient, which makes it difficult to meet the requirements of ground control under complex conditions. As a new support form with high strength and rigidity, the confined concrete arch plays an important

This study aims to investigate the effect of a cationic-anionic mixed collector (dodecyltrimethyl ammonium bromide/sodium oleate (DTAB/NaOL) on the selective separation of apatite, dolomite, and potassium feldspar. Herein, several experimental methods, including flotation experiments, zeta-potential detection, microcalorimetry detection, XPS analysis and FTIR measurements, were used. The flotation

Existing transversely isotropic poroelastodynamics solutions are limited to infinite domains and without experimental validation. Furthermore, there is a lack of analytical simulations for the elastic moduli dispersion of fluid-saturated porous cylinders. To address these three limitations and investigate the mechanisms of moduli dispersion, we present the analytical solutions of the poromechanical

Abstract not available

Sensor-based ore sorting is a technology used to classify high-grade mineralized rocks from low-grade waste rocks to reduce operation costs. Many ore-sorting algorithms using color images have been proposed in the past, but only some validate their results using mineral grades or optimize the algorithms to classify rocks in real-time. This paper presents an ore-sorting algorithm based on image processing

The concept of the carbon cycle in the old goaf of a coal mine based on CO2 utilization and storage was put forward adhering to the principle of low-carbon development, utilization of space resources in old goafs, and associated gas resources development. Firstly, the evolution characteristics of overburden fissures in the goaf of the case was studied using a two-dimensional physical similarity simulation

In this study, the innovative use of ethylenediamine tetramethylene phosphonic sodium (EDTMPS) as a calcite depressant in scheelite flotation was investigated by flotation experiments, and its selective depression mechanism was revealed by contact angle measurement, FTIR analysis, Zeta potential test and XPS analysis. The flotation experiment results showed that scheelite and calcite could be efficiently

Based on the underground powerhouse of Shuangjiangkou hydropower station, Octree theory is adopted to define the indices of the microseismic (MS) spatial aggregation degree and the deviation values of MS count and energy. The relationship between the MS multiple parameters and surrounding rock mass instability is established from three aspects: time, space, and strength. Supplemented by the center

The global energy transition is a widespread phenomenon that requires international exchange of experiences and mutual learning. Germany’s success in its first phase of energy transition can be attributed to its adoption of smart energy technology and implementation of electricity futures and spot marketization, which enabled the achievement of multiple energy spatial–temporal complementarities and

Investigations on the dynamic mechanical properties and failure mechanisms of coal under in-situ stress is essential for the prevention of dynamic disasters in deep coal mines. Thus, a modified true triaxial Hopkinson bar was employed to explore the dynamic mechanical behaviors of coal at different confining pressures (0–20 MPa) and strain rates (40–220 s−1). The results show that the dynamic peak

Permeability is a key parameter for coalbed methane development. Although the absolute permeability of coal has been extensively studied, wettability and pore structure properties continue to challenge the microscopic description of water-gas flow in coal. For this purpose, we reconstructed the microstructures of low-rank coal using micro-computed tomography (micro-CT) images. Pore geometry and pore-throat

Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two tunnels. However, the blasting load during excavation can sometimes damage the interlaid rock and threaten the stability of a tunnel’s structure. This paper presents a case study of the small clearance section of the Liantang highway tunnel project in Shenzhen, China

Abstract not available

A procedure to recognize individual discontinuities in rock mass from measurement while drilling (MWD) technology is developed, using the binary pattern of structural rock characteristics obtained from in-hole images for calibration. Data from two underground operations with different drilling technology and different rock mass characteristics are considered, which generalizes the application of the

Accurate knowledge of gas flow within the reservoir and related controlling factors will be important for enhancing the production of coal bed methane. At present, most studies focused on the permeability evolution of dry coal under gas adsorption equilibrium, gas flow and gas diffusion within wet coal under the generally non-equilibrium state are often ignored in the process of gas recovery. In this

Enargite is typically associated with chalcocite. Owing to the similarity in the flotation behaviors of these minerals, both minerals are reported to concentrate in the conventional flotation circuit. However, inorganic arsenic in enargite can decrease the copper concentrate quality and increase the operating cost of processing this concentrate. Separating these minerals is important for cleaner copper

Aiming at the problem of temperature-mechanics-chemical (T-M-C) action encountered by rocks in underground engineering, sandstone was selected as the sample for acid corrosion treatment at pH 1, 3, 5 and 7, the acid corrosion treated samples were then subjected to high-temperature experiments at 25, 300, 600, and 900 °C, and triaxial compression experiments were conducted in the laboratory. The experimental

Copper ions (Cu2+) are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology. The adsorption of Cu2+ and xanthate on the sulfidized surface was investigated in various systems, and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments

The unfrozen water content (UWC) of rocks at low temperature is an important index for evaluating the stability of the rock engineering in cold regions and artificial freezing engineering. This study addresses a new method to estimate the UWC of saturated sandstones at low temperature by using the ultrasonic velocity. Ultrasonic velocity variations can be divided into the normal temperature stage (20

A consecutive joint shear strength model for soft rock joints is proposed in this paper, which takes into account the degradation law of the actual contact three-dimensional (3D) roughness. The essence of the degradation of the maximum possible dilation angle is the degradation of the 3D average equivalent dip angle of the actual contact joint asperities. Firstly, models for calculating the maximum

The utilization of an appropriate collector or surfactant is crucial for the beneficiation of low-rank coal. However, in previous studies, the selection of surfactants was primarily based on flotation procedures, which hinders the understanding of the interaction mechanism between surfactant groups and oxygen-containing functional groups at the surface of low-rank coal. In this study, we investigate

The damage-fracture evolution of deep rock mass has obvious particularity, which is revealed in 2400-m-deep tunnels by field tests. The evolution of the excavation damaged zone depth is consistent with that of the fractured zone depth. The ratio of the excavation damaged zone depth to the excavation fractured zone depth is greater than 2.0 in a rock mass with both high strength and good integrity,

When the traditional drill and blast method is applied to rock crushing projects, it has strong vibration, loud noise and dust pollution, so it cannot be used in densely populated areas such as urban public works. We developed a supercritical CO2 true triaxial pneumatic rock-breaking experimental system, and conducted laboratory and field tests of dry ice powder pneumatic rock-breaking. The characteristics

The quantitative determination and evaluation of rock brittleness are crucial for the estimation of excavation efficiency and the improvement of hydraulic fracturing efficiency. Therefore, a “three-stage” triaxial loading and unloading stress path is designed and proposed. Subsequently, six brittleness indexes are selected. In addition, the evolution characteristics of the six brittleness indexes selected

A fractal model governing saw-tooth fractures was first introduced to replicate sandstone samples containing an inclined 3D penetrating rough fracture surface with various joint roughness coefficients (JRC). In conventional triaxial compression, the peak strength for fractured samples increased with both confining pressure and JRC. During the unloading confining pressure process, the normal stress