Shengli Yang

• D11 Xueyuan Road Beijing 100083， PRChina at China University Mining Technology，Beijing

Coal wall spalling characteristics and stability control mechanisms in steeply inclined coal seam (SICS) mining are more complex and dynamic due to the imbalanced mechanical constraint environment of the coal wall. This study investigates the characteristics of coal wall spalling in SICS mining using field measurements, theoretical analysis, and nu...

Longwall top coal caving (LTCC) mining technique is widely used in thick and extra-thick coal seams in China, India and Türkiye. Considering that the depth of coal seam varies widely (from 188 to 988 m in China), the different overburden pressure has great influence on the failure and drawing process of top coal in LTCC. In this paper, the top coal...

Considering the challenge posed by formidable mining pressure in the exploitation of island working faces, this study focuses on the control difficulties encountered in mining roadways. With the island working face 15,102 serving as the engineering context, the research delves into the lateral roof structure of the island working face. It scrutiniz...

The stability of the roof in coal mining plays a crucial role in ensuring safe excavation. After coal extraction, the roof experiences complex and unbalanced stress conditions, leading to diverse roof failure behaviors, particularly in the case of thick roofs. This study examines the failure behaviors of roofs with different thicknesses through a c...

Discrete element method (DEM) has been widely used in studying fracture development of rock due to its ability to accurately depict particle interactions. In order to more intuitively describe the fracture characteristics of the main roof during coal seam mining using DEM, a novel numerical model for generating irregular particles roof (IPRM) in PF...

Top coal is difficult to break and then flow out of the support opening at the end area of longwall top coal caving (LTCC) panels, which is an important source of the top coal loss and seriously restricts the further improvement of the top coal recovery. The end area of LTCC panels includes the arrangement area of roadway support and transition sup...

The recovery ratio of longwall top coal caving (LTCC) technology is an important measure of its effectiveness. However, the recovery ratio of single-opening sequential caving technology in thick and extra-thick coal seams needs improvement. To address this, an independent cluster-group caving technology is proposed in this study. Four numerical sim...

In order to achieve effective early warning of coal sample failure under uniaxial compression, the digital speckle technology is used to analyze the evolution process of the crack field and strain field of the specimen from the global and local aspects, and the development laws of the crack and the characteristics of the strain evolution are clarif...

This paper uses PFC2D software to carry out DEM numerical simulations of coal caving, calculates the top coal recovery under the same coal seam thickness and different rock layer thicknesses, analyzes the influence of the rock layer thickness on the top coal caving law in two different stages, and explains the necessity of a thick rock layer and th...

Using longwall top coal caving (LTCC) in an extra-thick seam, many problems appear, such as large broken top coal blocks, frequent arch formation in the drawing process, poor balance of drawing top coal and low top coal recovery, which seriously affect safe, efficient and green mining. In this study, the size distribution of top coal blocks was mea...

To study the response characteristics of coal samples to impact load under different surrounding pressures, the self-developed magnetic drop hammer impact device was used to measure the change of ultrasonic wave velocity before and after drop hammer impact, the internal damage of coal samples was quantitatively characterized, and then, the damage f...

Using a cluster of pebbles to generate clumps is a common procedure to explore granular particles' micro- or macro-scale mechanical responses in DEM simulations. The struggle is to balance the number of pebbles and the shape accuracy of generated clumps compared to the original particles. A low-cost multi-image-based method is adopted in this paper...

The longwall panel of the Jiulishan coal mine is affected by floor-confined water, while the roof rock weighting makes the production management of some longwall panels difficult. This has caused engineering methods of roof cutting and pressure release to be considered. To explore the dynamic effects of roof cutting and pressure release method, the...

With the increasing depth and intensity of coal mining, there is an increasing risk to the working face due to high static load and periodic breakage of the roof. The relation between the support and the surrounding rock under static–dynamic coupling loading disturbance is an important factor affecting the stability of the working face. In this stu...

Intelligent coal mining is an inevitable course for the high-quality development of the coal industry. The intellectualization development of longwall top coal caving (LTCC) face lags behind the fully mechanized face or heading face. The intelligent top coal caving is the core technology of achieving an intelligent top coal caving mining. However,...

Coal and gangue (black-gray solid wastes in coal) recognition is vital to avoid waste of resources and pollution of the environment during the coal production. Considering their color/temperature is very close to each other, the traditional visible image and infrared image analyzing method is hard to obtain satisfied recognition efficiency. Therefo...

Illuminance is a key factor in optical sorting in underground coal mining, since it affects the image grayscale and texture features, especially for objects that are sensitive to light, such as bright coal. Appropriate illuminance is beneficial for improving the accuracy of image-based rock mixing ratio estimation, which is essential for optical so...

This review details the state of the art in research on top coal drawing mechanisms in Longwall top coal caving (LTCC) by examining the relevant literature over the last two decades. It starts with an introduction of the brief history and basic procedures of LTCC. The framework of research on the drawing mechanism, basic concepts, and some theoreti...

Illuminance management of halogen lamp (HL) affects energy consumption and lighting effect. A smart control methodology of illuminance for light sources based on HL was described in this study. Based on the illuminance analysis model and experimental works, the relationship between power, illuminance and depth of light sources, i.e. single HL and c...

Discrete element method Voro noi tessella tion Ro ck fr acturing behavior UCS-toTS ra tio Strength envelo pe ABSTRACT Particle-based model (PBM) has be en extensively used to investigate progressive failure process of rock du e to its advantage in modeling fracture developme nt. In order to ma ke the PBM reprodu ce rock failure be havior more reali...

Intelligent lighting is responsible for providing an appropriate illuminance and balancing the environment and resources. An appropriate illuminance can improve visual effect of machine recognition, while it is always difficult to be measured and controlled. An illuminance measurement method by using depth measurement technology of binocular stereo...

The dynamic hazards in the open face area caused by the impact load of the massive strong roof become increasingly severe with the increase in the cutting height of the longwall face and its depth of cover. Understanding the strata-shield interaction under the dynamic impact loading condition may relieve the dynamic hazards. In this paper, a 3D phy...

Due to the unbalanced top coal drawing process, the recovery ratio is low, and the equipment stability is poor in the longwall top coal caving mining (LTCC) with an inclined seam. Aimed at these problems, this paper proposes the dynamic group caving method (DGCM). The basic procedure is that when the drawn volume of top coal from a support reaches...

Mechanical behavior of the rock in tensile stress environment remains an unresolved problem in the underground mining, where surrounding rocks commonly experience tensile failure. In the present study, tensile failure behavior of three types of sedimentary rocks is investigated experimentally and numerically. The deformation response, fracture prop...

The broken positions of the overlying strata might lead to different geometric configurations of the caving overburden and also have an impact on the coal mine pressure behaviors and dynamic mine hazards in the open face area. This paper has developed a roof failure analytical model combining the beam on the elastic foundation theory and the cantil...

To reveal the disaster-causing mechanism of roof collapse in horizontal sublevel top-coal caving faces for steeply inclined thick seams, a mechanical model is proposed based on the engineering background of the Jiangcang #1 coal mine in China. It is indicated that there is a “toppling–slumping” roof failure mode in horizontal sublevel top-coal cavi...

Longwall face fall in the open face area is one of the most difficult ground control problems in mining thick coal seams in China especially under difficult geological conditions. This paper has proposed a new flexible bolting and grouting technology for face support. The flexible support method includes face support using flexible coir ropes and f...

Fully grouted rock bolts are widely used in civil engineering and mining engineering, playing a significant role in keeping the stability and safety of excavations. In this paper, the load transfer mechanism of fully grouted rock bolts was studied with an analytical model. A trilinear model was used to depict the bond-slip behaviour of the bolt/gro...

In the present study, mechanical behaviour of three types of rocks has been investigated under uniaxial compression. The stress–strain responses of the tested rocks are composed of four regions: the compaction stage; elastic stage; strain hardening stage and strain softening stage. The elastic modulus and uniaxial compressive strength increase in o...

The coupling effect of freeze-thaw (F-T) temperature and dynamic load on the dynamic mechanical properties and fracture mechanism of saturated yellow sandstone was experimentally investigated in this research. The dynamic compression tests on the specimen after different F-T temperatures (i.e., −5°С, −10°С, −15°С, −20°С, −30°С, and 20°С) have been...

In longwall top-coal caving (LTCC) mining, progressive failure process of top coal is closely related to the mining-induced stress. In order to achieve failure mechanisms of the top coal, stress distribution of the LTCC face adjacent to the gob is analysed in this study with field investigation and numerical simulation. The concentration and rotati...

Face falls of longwall are the most complex ground control problem in mining thick coal seams in China. In this study, the mechanism of face failure is assessed from the perspective of shield–strata interaction. The paper develops a better understanding of fundamental mechanism of face failure and shield–strata interaction through a theoretical coa...

The increase in the cover depth and length of longwall face leads to some drastic changes in mine pressure occurrence and spatial distribution.Such changes result in a great challenge in surrounding rock control.In order to realize an effective control of the abnormal mine pressure occurrences, happening frequently and difficult to be predicted in...

To reveal the law of roof failure and movement, the Face 11220 in Jiangcang 1# coal mine was investigated by a roof failure physical model, a UDEC numerical model and a roof failure mechanical model. It is revealed that the roof fails in two modes, i.e. toppling in the upper section and slumping in the lower section. Based on the theoretical model,...

Longwall top-coal caving (LTCC) is widely employed in the underground mining of thick coal seams. The technique divides a thick coal seam into a lower and an upper section. The bottom coal is sheared by a cutting head and transported by a conveyor in front of the support while the top coal fails and caves under mining pressure, transported by a con...

Face fall remains one of the most difficult ground control problems in single-pass thick seam longwall mining which affects the safety and production. The mechanism of face failure is analyzed using Ritz method,and the code formation characteristics of the " roof-support-face" system are revealed through the 3D physical modeling study. The results...

Face fall remains one of the most difficult ground control problems in single-pass thick seam longwall mining which affects the safety and production. The mechanism of face failure is analyzed using Ritz method, and the co-deformation characteristics of the "roof-support-face" system are revealed through the 3D physical modeling study. The results...

A deterministic approach is frequently used in engineering design. In this quantitative design methodology, a safety factor, which is typically a strength-to-stress ratio, is derived as an index for the stability assessment of the engineering design. In underground coal mining applications such as pillar design, however, the inputs of pillar design...

The support and surrounding rock relationship is affected by the loose top-coal in longwall top-coal caving mining (LTCC). The dynamic load tests under different particle types, particle sizes, particle packing thicknesses and impact forces were carried out by using the self-developed dynamic load impact test device, and revealed the influence of l...

A thorough understanding of the deformation behavior, damage accumulation, and progressive failure of heterogeneous coal is a prerequisite for effective control of the surrounding rock and efficient exploitation of resources in underground coal mines. Such understanding can be obtained by analyzing both the macro- and meso-responses of coal to load...

In response to the fact that rib spalling affects the normal production seriously in large-cutting-height panel, a method for the determination of support capacity based on coal face stability control has been proposed. Taking panel 8101 as a background, a “coal face-support-roof” mechanical model has been established to analyze the relationship be...

Taking the extremely inclined panel No.1201 in Dayuan coal mine, Fengfeng group, as the engineering background, the basic problems of the longwall top-coal caving mining technique in extremely inclined and soft thick coal seam were systematically studied.The results reveal that the rational design of shield supports is the first necessity for the s...

In this paper, an overlying strata breakage prediction experiment platform was developed and used to simulate the dynamic load impact in shallow working face with thin-bedrock.A breaking model of roof strata based on the elastic foundation beam model was proposed to calculate the relative position between main roof's breaking and coal wall and anal...

Anyang is known to be a high-incidence area of esophageal cancer (EC) in China. Among a long list of risk factors, the quality of drinking water was evaluated. We have selected 3806 individuals and collected 550 drinking water samples correspondent with this not-matched case-control survey. There are 531 EC patients included based on Population Can...

Purpose: Targeting the protein neddylation pathway has become an attractive anticancer strategy; however, the role of death receptor–mediated extrinsic apoptosis during treatment remained to be determined. Experimental Design: The activation of extrinsic apoptosis and its role in MLN4924 treatment of human esophageal squamous cell carcinoma (ESCC)...

Dynamic failure or even rock burst makes it difficult to keep surrounding rock stay in good control in high intensity mining face. Experimental, theoretical and numerical simulation methods are used in this study to analyze geotechnical material failure feature and strain energy distribution formation in the surrounding rock under intense mining ac...

Based on the failure control conditions of "intensity parameters-stress environment-weak planes of joints" in coal-rock mass, the failure characteristic of overlying strata in large mining height face was studied, the simulation of failure process was conducted in the laboratory, and the determination of support resistance was theoretically analyze...

Esophageal squamous cell carcinoma (ESCC) is the most common cancer in China, and multidrug resistance (MDR) remains one of the biggest problems in ESCC chemotherapy. In this study, we aimed to investigate the mechanism of Caveolin-1, an integral membrane protein, on regulating ESCC MDR. First, immunohistochemistry was used to check the protein exp...

The complex variable theory is employed to find the analytical solution for rock stress around square tunnels in a homogeneous, isotropic and elastic rock mass. The solution is more accurate than previous available solutions, because the first three terms of transformation function are taken in the early deduction. We find that in situ stress and c...

The stability control of longwall coalface is the key technology of large-cutting-height mining method. Therefore, a systematic study of the factors that affect coalface stability and its control technology is required in the development of large-cutting-height mining method in China. After the practical field observation and years of study, it was...

The development of techniques and equipment for single-pass high-seam longwall mining in China is reviewed. Some methods used to obtain the fractured zone height are discussed. The boundary between the caved and fractured zones is generally not clear, but one important difference that distinguishes the two zones is that horizontal compressional for...

The determination of the correct design support capacity of shield supports is the key to the safe control of strata within the vicinity of longwall coal panels. There are a number of design methods that have been developed, dependant on the prevalent geological and mining conditions. However, these methods have been found to be inappropriate to th...

In terms of the actual impact of rib spalling on production in large mining height coal face, a flexible reinforcement technique of rib spalling is put forwarded in this study. Based on the deformation characteristics of coal face and flexible reinforcement mechanism, the mechanic properties of manila is analyzed by using the drawing experiment. Th...

The spatial shape of coal-gangue draw body and 3-D distribution of top-coal recovery ratio were studied by 3-D similar simulation experiment and numerical simulation analysis based on the loose medium flow field theory. The results show that the drawing volume of top-coal caving face in near horizontal coal seam with multi-gangue increases from upp...

The coal wall grouting reinforcement technique is an effective measure to prevent and control rib spalling, and its key procedure is the selection of grouting quantity. To overcome the difficulty in choosing the reasonable grouting quantity, an experimental scheme "The fragmentized and broken coal molded again with mixed slurry" has been designed....

The top-coal caving mining method, developed steadily in the past two decades, has become the main method for thick seam coal mining in China. In recent years, the core research areas in the top-coal caving mining are the mechanisms of top-coal caving and the improvement of top-coal recovery ratio. In this paper, the mechanisms of the top-coal cavi...

In underground mining, floor failure depth accompanying mining phases usually results from changes in the advance abutment pressure in the coal mass, and changes in stress redistribution in the areas that have already been mined. Although a variety of techniques have been applied to determine the failure depth, and a number of studies have provided...

The movement features of overlying strata are different from that of mining by caving method since gob areas are occupied by fillingsand the processes of faces mining and gangue filling were simulated in laboratory by numerical calculations.Stress changes and movement features of overlying strata were simulated under different filling ratio conditi...

Caveolin-1 (Cav-1) isoforms, including Cav-1α and Cav-1β, were identified as integral membrane proteins and the major components of caveolae. Cav-1 proteins are highly conserved during evolution from {itCaenorhabditis elegans} to human and are capable of interacting with many signaling molecules through their caveolin scaffolding domains to regulat...

Taking Adaohai Coal Mine as the example, underground pressure appearance laws of fully mechanized top coal slice caving on high-dipping and thick coal seams. Through site visit, theoretical analysis and discrete element calculation, the research shows that, as the mining deepens, underground stress of lower sublevels is more obvious and higher than...

Objective. To investigate the exposure levels of Alternaria alternata toxins and evaluate the prevention effects for esophageal cancer in the high incident area of Linxian, China. Methods. Alternaria alternata toxins in grain and urine were measured using thin-layer chromatography. The current exposure levels were compared with the previous exposur...