At a time when the world is practicing energy conservation and emission reduction in order to achieve carbon neutrality, it is particularly important to enhance the extraction of valuable metals from low-grade resources. In the current process of extracting valuable metals from limonitic laterite, the characteristic that the laterite is a highly porous mineral is often overlooked. Inspired by our previous

Solids production is a complex physical process which is controlled by several factors including mechanical failure from in-situ stresses and hydrodynamic erosion from fluid flow. Hydrodynamic models for the prediction of sand production involve sanding criteria based on filtration theories. Such models contain a constitutive model parameter, the coefficient λ, with dimensions of inverse length which

Various fracture patterns may develop through hydraulic fracture propagation and interaction with natural fractures which may substantially enhance connectivity and connected fracture surface area in low-permeability formations. Key factors controlling this behavior are analyzed using the continuum simulator TOUGHREACT-FLAC3D that couples the evolution of stress and deformation (FLAC3D) with reactive

The materials with different elastic behavior under tension and compression are called bi-modulus materials, and this type of materials widely exists in nature, such as rock, concrete, and cohesive soil. However, due to the lack of a constitutive model that is suitable for bi-modulus materials, the bi-modulus property of materials was often ignored in previous studies. In this study, the uncoupled

The difficulty in the 3D analysis of a circular tunnel excavation lies in the selection of a reasonable softening equation for the out-of-plane stress (σz) in the plastic zone. This study developed and compared the semi-analytical solutions of a circular opening considering different approaches for obtaining σz, and the results were verified by the numerical results (1) The elastic approaches (e.g

The partition curve is an important tool to evaluate the separation performance of mineral separators like dense medium cyclones (DMCs). This curve is constructed by float-and-sink (FaS) analysis which involves the use of heavy liquids and suspensions. This traditional technique is hazardous to the environment, laborious, and time-consuming. Here, a new technique using X-ray computed tomography (XCT)

The mixed anionic/cationic collector sodium oleate/ N-lauryl-1, 3-propylene diamine (NaOL/ND13) was firstly used to separate spodumene from feldspar and exhibited high selectivity. The flotation experiments of single and artificial-mixed mineral showed that the mixed NaOL/ND13 (NaOL: ND13 = 5:1) exhibited excellent flotation separation performance for spodumene from feldspar at pH 8.0. The zeta potential

Understanding and predicting the propagation and disturbance of multiple fractures is the key to the successful implementation of hydraulic fracturing. In this study, the two-hole fracturing tests are carried out on granite samples by using soundless cracking demolition agent (SCDA). Combined with the extended finite element method (XFEM) simulation and the induced stress analysis, the interaction

In mountain areas, flexural buckling failure of layered rock slopes due to self-weight is common, and it frequently results in serious disasters. Previous research has focused on qualitatively evaluating slope buckling stability and rarely studied the whole process from deformation to failure. In this work, we intend to quantitatively analyze the progressive movement of buckling landslide by solving

A Split-Hopkinson pressure bar was used to carry out a series of impact tests on prefabricated granite specimens containing joints with different inclination angles and at different joint persistency values. The results were used to determine the degradation effect of the non-persistent joints on the specimens and investigate the failure mechanism of the granite subjected to impact load. The effect

Determining the rock mass structure of an excavation face is important for the safe construction of tunnels. Traditional artificial detection poses a threat to personnel and property; thus, it is necessary to develop unmanned detection technology. This paper innovatively develops an efficient method for detecting joints in rock tunnels based on laser scanning, and an intelligent robot is then designed

This paper addresses hydraulic fracture initiation from an initially notch-free wellbore situated in an anisotropic host rock, where the rock mass is subjected to an in-situ stress state that is also anisotropic in nature. In such conditions, hydraulic fracture initiation is fully characterized by three parameters, namely initiation pressure, initiation orientation, and initiation length. While a strength-based

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)

Rapid advances in electronics and telecommunications technologies have contributed significantly to making e-waste one of the largest and fastest-growing solid waste streams. India produces over 3.23 million tonnes of e-waste each year. Over 90% of the total e-waste generated in the country is processed by the informal waste management sector. Informal waste collectors in India are known as ‘kabadiwalas’

Particle-bubble aggregates in flotation are characteristic of particle-laden bubbles and surfaces, but the available theories focus on the stability and detachment of single particle that resides lonely at the free surface. There is no modelling attempt to quantify the particle stability and detachment from the laden surfaces that can be relevant to flotation. Here, we developed a model that considers

Natural fractures have been often generated with rough morphologies as a result of complex geological processes. Joint surface undulation/roughness degree dominantly affects mechanical characteristics of jointed rock masses, hence should be considered in geometrical modeling of fracture networks. Considering the intrinsic geometric characteristic of natural fractures, this paper proposes a method to

Cave mining has inherent risks, which include rock bursts, collapses, subsidence, and inrushes. Among the inrush events that can occur are the inflows of water, mud, and dry-fine material. The latter type of inflow is one about which we have the least amount of information and little research, despite the fatal consequences that have occurred associated with this phenomenon. In this work, the inrush

To better understand the shear creep characteristics of joints under wetting-drying cycles, multi-stage shear creep experiments are firstly conducted on the joints subjected to different wetting-drying cycles. Then, the shear creep damage characteristics of joints are investigated from the microscopic and macroscopic perspectives through wave velocity tests, scanning electron microscope observations

This paper presents the results of tensile load tests performed with instrumented model of a tunnel-type anchorage (TTA) installed in a rock mass simulated model material in a rectangular chamber with digital image correlation (DIC) capability. Digital images of the model were captured during the test; the processing of these images using the DIC technique yielded the surrounding rock displacement

This study proposes a new two-dimensional finite-discrete element method (FDEM) using dynamically inserted cohesive elements. Unlike the conventional FDEM, which sets up cohesive elements between adjacent solid elements to simulate fracture and fragmentation in the geomaterials, the new FDEM adaptively inserts the cohesive elements when the stress exceeds a critical value. The new method is consistent

This paper presents a computational framework for modelling of fluid pressurised fracture propagation in saturated porous media. The framework rests on the principle of the variational phase-field theory to predict the fracture propagation pathway. The paper sets out the variational formulations and associated weak forms of the partial differential equations describing the pressure-deformation interplays

Rock fragmentation is vital in a sublevel caving operation. The oversize fragments are the most undesired fragmentation category because of their challenges; as such, they require special attention. This study carried out a field test in one of the LKAB’s iron ore mines in northern Sweden to analyse the occurrence of oversize fragments. The analysis involved correlation and regression tests and was

Estimating material properties is an essential part of any engineering field. In rock mechanics, obtaining an infinite number of samples and/or samples at desired orientations is often not possible. Thus, replica materials have been extensively used to serve in the laboratory as analogues of natural rock. In this note, a framework is established to assess the suitability of a replica material to replicate

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

Tensile and shear fracture behaviors of fiber-reinforced cemented paste backfill (FRCPB) play critical roles in the safe and cost-effective engineering design of underground mine backfill structures. Sulfate pore solution is a key factor affecting the time-dependent evolution of fracture behavior and properties of FRCPB. However, no studies have been carried out to systematically investigate its effects

Hot dry rock (HDR) is a kind of clean, renewable energy and has received widespread attention worldwide in recent years. It is significant to explore the dynamic tensile properties of thermal-treated granite using different cooling methods for mining HDR. In the current work, a series of tests were performed containing ultrasonic testing and Split Hopkinson Pressure Bar (SHPB) tests on granite at different

Compression testing schemes that induce failure in rock specimens primarily through a reduction in confining stress have become increasingly common in recent years. Despite this, the interpretation of the results from such studies are fraught with complications due to the large number of factors that can influence the outcome of such tests relative to standard compression tests that follow a loading

The rock drilling and blasting method is the most commonly adopted method for rock roadway excavation in China, where cutting efficiency is the key factor affecting the excavation speed. The conventional wedge-shaped cut blasting is not suitable for deep hole blasting since the method requires the explosives to be concentrated at the bottom of the borehole, resulting in uneven fragmentation of the

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

Tensile strength is one of the important mechanical properties of rock and rock-like materials and its accurate estimation and understanding of its failure mechanism are crucial for efficient design of structures on or within the rock masses. Amongst various approaches developed for estimating this property, Brazilian testing has received considerable attention analytically, numerically and experimentally

Abstract not available

Hydraulic fracturing (HF) has been widely used in coal and rock dynamic disasters prevention and control and coalbed methane production in underground coal mines. However, how to effectively and accurately monitor and evaluate the hydraulic crack propagation process and impact range has not been resolved. We developed a novel experimental system for HF-direct current (DC) monitoring under true triaxial

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

The unique properties of certain metals have made them indispensable in manufacturing advanced technological devices and for use in the green economy. However, these metals are not infinite, and the average ore grades in mines have been decreasing in recent decades. This study examines energy consumption as a function of ore grade decline for Nickel, Cobalt, and platinum group metals (PGMs), using

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

The flotation separation of bastnaesite and monazite is challenging due to their similar physicochemical properties and floatability. In this work, an environmentally friendly depressant, dextrin hydrate (DH), was introduced for the flotation separation of bastnaesite from monazite using caprylhydroxamic acid (CHA) as the collector. The flotation behavior of bastnaesite and monazite in the absence

Developing a flotation benchmark to compare different flotation systems has been challenging due to the variation that exists in flotation cell types, geometry, and internal hydrodynamics. Parkes et al (2022) focused on the product flux passing through the upper surface as a Performance Measure, interpreting a batch mechanical cell as a steady-state plug flow device, equivalent to infinite steady-state

Stress-dependent hydraulic conductivity tensor is formulated in a closed form on the basis of Oda's permeability tensor and Bianchi & Snow's proposal for change of the crack aperture. Using a simple cracked model, a general equation is derived to obtain the hydraulic conductivity tensor as a function of depth and the coefficient of earth pressure at rest. The general trend of the equation is consistent

Technology, in addition to supply and demand, is driving current advances in mineral processing. Over the past three decades, demand for various minerals has continued to rise, while the mineral processing sector has faced challenges such as the need for more sophisticated ore treatment, lower plant feed quality, and poorer plant performance due to mixing of ores with varying characteristics. Gravity

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

The quaternary ammonium salt collectors display great application prospects in minerals flotation, and introducing the second polar group has been an effective method to enhance the performance of flotation reagents. In this study, the hydroxyl group was introduced into quaternary ammonium salt to design and synthesize a novel containing hydroxyl group quaternary ammonium salt collector dodecyl hydroxyethyl

In order to study the dynamic mechanics and failure behavior of jointed rock masses, impact tests were carried out on sandstone specimens with intersected jointed and unjointed intact sandstone specimens using a modified split Hopkinson pressure bar (SHPB) with confinement. The effects of intersected artificial joints on the dynamic properties and failure mechanism of sandstone samples were analyzed

A novel pseudo-Gemini collector (PGC) featuring pH-responsive collecting power and enhanced selectivity is developed for flotation recovery of fine copper oxides from silica. The switchable PGC is formed through ionic pairing between protonated triethylenetetramine (TETA) and deprotonated oleic acid (OA) and is referred to as T-OA. The formation of T-OA was characterized by determining its critical

Much of the remaining iron ore resources in Brazil consist of low-grade itabirite ores. Accordingly, a typical beneficiation circuit includes a four-staged crushing/screening plant, followed by grinding in a closed-circuit ball mill, desliming in hydrocyclones and final ore mineral concentration via multistage reverse flotation and thickening of the final product. With the need for decarbonisation

The shear process can significantly affect the hydro-mechanical properties of rock fractures. In the present study, a new approach is developed to predict the direct shear process of rock fractures under the constant normal load condition. This approach is validated by three sets of laboratory direct shear test data and it is then used to study the impact of rock mechanical properties on the shear

Grinding and a flash flotation cell are frequently installed to recover fast floatability coarse particles avoiding their regrinding. However, the ore textural characteristics, such as grain size, change during mine operation and consequently the recovery of valuable particles in the flash flotation cell decreases. This article proposes and validates an interesting method of solving the problem of